X .tk%
FR 1C
■ri''~v, Z.
"‘"'J.QP
DISSERTATION FIRST
EXHIBITING A GENERAL VIEW
OF THE
PROGRESS OF METAPHYSICAL AND ETHICAL PHILOSOPHY
SINCE THE REVIVAL OF LETTERS IN EUROPE.
By DUGALD STEWART, Esq. F.R.SS. Lond. and Edin.,
LATE PROFESSOR OF MORAL PHILOSOPHY IN THE UNIVERSITY
OF EDINBURGH.
■
.
PREFACE,
CONTAINING SOME CRITICAL REMARKS ON THE DISCOURSE PREFIXED TO THE
FRENCH ENCYCLOPEDIA
WHEN I ventured to undertake the task of
contributing a Preliminary Dissertation
to the Encyclopedia Britannica, my original in¬
tention was, after the example of D’Alembert,
to have begun with a general survey of the va¬
rious departments of human knowledge. The
outline of such a survey, sketched by the com¬
prehensive genius of Bacon, together with the
corrections and improvements suggested by his
illustrious disciple, would, I thought, have ren¬
dered it comparatively easy to adapt their intel¬
lectual map to the present advanced state of the
sciences; while the unrivalled authority which
their united work has long maintained in the
republic of letters, would, I flattered myself,
have softened those criticisms which might be
expected to he incurred by any similar attempt
of a more modern hand. On a closer examina¬
tion, however, of their labours, I found myself
under the necessity of abandoning this design.
Doubts immediately occurred to me with respect
to the justness of their logical views, and soon
terminated in a conviction that these views are
radically and essentially erroneous. Instead,
therefore, of endeavouring to give additional
currency to speculations which I conceived to
he fundamentally unsound, I resolved to avail
myself of the present opportunity to point out
their most important defects;—defects which, I
am nevertheless very ready to acknowledge, it
is much more easy to remark than to supply.
The critical strictures which, in the course of
this discussion, I shall have occasion to offer on
my predecessors, will, at the same time, account
for my forbearing to substitute a new map of
my own, instead of that to which the names of
Bacon and D’Alembert have lent so great and
so well-merited a celebrity; and may perhaps
suggest a doubt, whether the period be yet ar¬
rived for hazarding again, with any reasonable
prospect of success, a repetition of their bold
experiment. For the length to which these
strictures are likely to extend, the only apology
I have to offer is the peculiar importance of the
questions to which they relate, and the high au¬
thority of the writers whose opinions I presume
to controvert.
Before entering on his main subject, D’Alem¬
bert is at pains to explain a distinction—which he
represents as of considerable importance—^be¬
tween the Genealogy of the sciences, and the
Encyclopedical arrangement of the objects of
human knowledge.1 “ In examining the for¬
mer,” he observes, “ our aim is, by remounting
1 “ 11 ne faut pas confondre I’ordre Encyclopedlque des connoissances humaines avee la Gdneaiogie des Scieneeo.”
Avertissement, p. 7-
DISS. I. PART I. A
2
PRELIMINARY DISSERTATIONS.
to the origin and genesis of our ideas, to trace
the causes to which the sciences owe their birth;
and to mark the characteristics hy which they
are distinguished from each other. In order to
ascertain the latter, it is necessary to compre¬
hend, in one general scheme, all the various de¬
partments of study; to arrange them into pro¬
per classes; and to point out their mutual rela¬
tions and dependencies.” Such a scheme is some¬
times likened hy D’Alembert to a map or chart
of the intellectual world; sometimes to a Ge¬
nealogical1 or Encyclopedical Tree, indicating
the manifold and complicated affinities of those
studies, which, however apparently remote and
unconnected, are all the common offspring of
the human understanding. For executing suc¬
cessfully this chart or tree, a philosophical deli¬
neation of the natural progress of the mind may
(according to him) furnish very useful lights;
although he acknowledges that the results of the
two undertakings cannot fail to differ widely in
many instances,—the laws which regulate the
generation of our ideas often interfering with
that systematical order in the relative arrange¬
ment of scientific pursuits, which it is the pur¬
pose of the Encyclopedical Tree to exhibit.2
In treating of the first of these subjects, it can¬
not he denied that D’Alembert has displayed
much ingenuity and invention; hut the depth
and solidity of his general train of thought may
he questioned. On various occasions, he has
evidently suffered himself to he misled hy a spi¬
rit of false refinement; and on others, where
probably he was fully aware of his inability to
render the theoretical chain complete, he seems
to have aimed at concealing from his readers the
faulty links, hy availing himself of those epi¬
grammatic points, and other artifices of style,
with which the genius of the French language
enables a skilful writer to smooth and varnish
over his most illogical transitions.
The most essential imperfections, however, of
this historical sketch, may he fairly ascribed to
a certain vagueness and indecision in the au¬
thor’s idea, with regard to the scope of his in¬
quiries. What he has in general pointed at is
to trace, from the theory of the Mind, and from
the order followed by nature in the develope-
ment of its powers, the successive steps hy which
the curiosity may he conceived to have been
gradually conducted from one intellectual pur¬
suit to another; hut, in the execution of this
design (which in itself is highly philosophical
and interesting), he does not appear to have
paid due attention to the essential difference
between the history of the human species, and
that of the civilised and inquisitive individual.
The former was undoubtedly that which prin¬
cipally figured in his conceptions, and to which,
I apprehend, he ought to have confined himself
exclusively; whereas, in fact, he has so com¬
pletely blended the two subjects together, that
it is often impossible to say which of them was
uppermost in his thoughts. The consequence
is, that, instead of throwing upon either those
strong and steady lights, which might have been
expected from his powers, he has involved both
in additional obscurity. This indistinctness is
more peculiarly remarkable in the beginning of
his Discourse, where he represents men in the
earliest infancy of science, before they had time
to take any precautions for securing the means
of their subsistence, or of their safety,—as phi¬
losophising on their sensations, on the exist¬
ence of their own bodies, and on that of the
material world. His Discourse, accordingly,
sets out with a series of Meditations, precisely
analogous to those which form the introduction
1 It is to be regretted, that the epithet Genealogical should have been employed on this occasion, where the author s wish
was to contradistinguish the idea denoted by it, from that historical view of the sciences to which the word Genealogy had
been previously applied. . .
2 The true reason of this might perhaps have been assigned in simpler terms by remarking^ that the order of invention
is, in most cases, the reverse of that fitted for didactic communication. This observation applies not only to the analytical
and synthetical processes of the individual, but to the progressive improvements of the species, when compared with the
arrangements prescribed by logical method, for conveying a knowledge of them to students. In an enlightened age, the
sciences are justly considered as the basis of the arts ; and, in a course of liberal education, the former are always taught
prior to the latter. But, in the order of invention and discovery, the arts preceded the sciences. Men measured land
before they studied speculative geometry ; and governments were established before politics were studied^ as. a science. A
remark somewhat similar is made by Celsus, concerning the history of medicine : “ Non medicinam ration! esse posterio-
rem, sed post medicinam inventam, rationem esse qusesitam.”
PREFACE TO THE FIRST DISSERTATION.
3
to the philosophy of Descartes; meditations
which, in the order of time, have been uniform¬
ly posterior to the study of external nature;
and which, even in such an age as the present,
are confined to a comparatively small number
of recluse metaphysicians.
Of this sort of conjectural or theoretical his¬
tory, the most unexceptionable specimens which
have yet appeared, are indisputably the frag¬
ments in Mr Smith’s posthumous work on the
History of Astronomy, and on that of the An¬
cient Systems of Physics and Metaphysics.
That, in the latter of these, he may have occa¬
sionally accommodated his details to his own
peculiar opinions concerning the object of Phi¬
losophy, may perhaps, with some truth, be al¬
leged ; but he must at least be allowed the me¬
rit of completely avoiding the error by which
D’Alembert was misled; and, even in those in¬
stances where he himself seems to wander a
little from the right path, of furnishing his suc¬
cessors with a thread, leading by easy and al¬
most insensible steps, from the first gross per¬
ceptions of sense, to the most abstract refine¬
ments of the Grecian schools. Nor is this the
only praise to which these fragments are en¬
titled. By seizing on the different points of
view from which the same object was contem¬
plated by different sects, they often bestow a
certain degree of unity and of interest on what
before seemed calculated merely to bewilder
and to confound; and render the apparent aber¬
rations and caprices of the understanding, sub¬
servient to the study of its operations and laws.
To the foregoing strictures on D’Alembert’s
view of the origin of the sciences, it may be
added, that this introductory part of his Dis¬
course does not seem to have any immediate
connection with the sequel. We are led, in¬
deed, to expect, that it is to prepare the way
for the study of the Encyclopedical Tree after¬
wards to be exhibited; but in this expectation
we are completely disappointed,—no reference
to it whatever being made by the author in the
farther prosecution of his subject. It forms,
accordingly, a portion of his Discourse altoge¬
ther foreign to the general design; while, from
the metaphysical obscurity which pervades it,
the generality of readers are likely to receive an
impression, either unfavourable to the perspi¬
cuity of the writer, or to their own powers of
comprehension and of reasoning. It were to be
wished, therefore, that, instead of occupying the
first pages of the Encyclopedic, it had been re¬
served for a separate article in the body of that
work. There it might have been read by the
logical student, with no small interest and ad¬
vantage ; for, with all its imperfections, it bears
numerous and precious marks of its author’s
hand.
In delineating his Encyclopedical Tree, D’A¬
lembert has, in my opinion, been still more un¬
successful than in the speculations which have
been hitherto under our review. His venera¬
tion for Bacon seems, on this occasion, to have
prevented him from giving due scope to his own
powerful and fertile genius, and has engaged
him in the fruitless task of attempting, by means
of arbitrary definitions, to draw a veil over in¬
curable defects and blemishes. In this part of
Bacon’s logic, it must, at the same time, be
owned, that there is something peculiarly capti¬
vating to the fancy; and, accordingly, it has
united in its favour the suffrages of almost all
the succeeding authors who have treated of the
same subject. It will be necessary for me,
therefore, to explain fully the grounds of that
censure, which, in opposition to so many illus¬
trious names, I have presumed to bestow on it.
Of the leading ideas to which I more particu¬
larly object, the following statement is given by
D’Alembert. I quote it in preference to the
corresponding passage in Bacon, as it contains
various explanatory clauses and glosses, for
which we are indebted to the ingenuity of the
commentator.
“ The objects about which our minds are oc¬
cupied, are either spiritual or material, and the
media employed for this purpose are our ideas,
either directly received, or derived from reflec¬
tion. The system of our direct knowledge con¬
sists entirely in the passive and mechanical ac¬
cumulation of the particulars it comprehends;
an accumulation which belongs exclusively to
the province of Memory. Reflection is of two
kinds, according as it is employed in reasoning
on the objects of our direct ideas, or in study¬
ing them as models for imitation.
4
PRELIMINARY DISSERTATIONS.
“ Thus, Memory, Reason, strictly so called, of its successive operations on the subjects of
and Imagination, are the three modes in which thought, hy creating abstract and general ideas,
the mind operates on the subjects of its thoughts, remote from the perceptions of sense, leads to
By Imagination, however, is here to he under- the exercise of Imagination as the last step of
stood, not the faculty of conceiving or repre- the process. Thus metaphysics and geometry
senting to ourselves what we have formerly per- are, of all the sciences belonging to Reason,
ceived a faculty which differs in nothing from those in which Imagination has the greatest
the memory of these perceptions, and which, if it share. I ask pardon for this observation from
were not relieved hy the invention of signs, those men of taste, who, little aware of the near
would he in a state of continual exercise. The affinity of geometry to their own pursuits, and
power which we denote hy this name has a still less suspecting that the only intermediate
nobler province allotted to it, that of render- step between them is formed by metaphysics,
ine imitation subservient to the creations of are disposed to employ their wit in depreciating
genius its value. The truth is, that, to the geometer
“ These three faculties suggest a correspond- who invents, Imagination is not less essential
ing division of human knowledge into three than to the poet who creates. They operate,
branches, 1. History, which derives its materials indeed, differently on their object, the former
from Memory; 2. Philosophy, which is the pro- abstracting and analyzing, where the latter corn-
duct of Reason; and 3. Poetry (comprehending bines and adornstwo processes of the mind,
under this title all the Fine Arts), which is the it must at the same time he confessed, which
offspring of Imagination.1 If we place Reason seem from experience to he so little congenial,
before Imagination, it is because this order ap- that it may he doubted if the talents of a great
pears to us conformable to the natural progress geometer and of a great poet will ever he united
of our intellectual operations.2 The Imagina- in the same person. But whether these talents
tion is a creative faculty; and the mind, before he or he not mutually exclusive, certain it is,
it attempts to create, begins by reasoning upon that they who possess the one, have no right to
what it sees and knows. Nor is this all. In despise those who cultivate the other. Of all
the faculty of Imagination, both Reason and the great men of antiquity, Archimedes is per-
Memory are, to a certain extent, combined,— haps he who is the best entitled to he placed hy
the mind never imagining or creating objects the side of Homei.
hut such as are analogous to those whereof it D’Alembert afterwards proceeds to observe,
has had previous experience. Where this ana- that of these three geneial blanches of the En
logy is wanting, the combinations are extrava- cyclopedical Tree, a natural and convenient suh-
gant and displeasing; and consequently, in that division is afforded by the metaphysical distri-
agreeahle imitation of nature, at which the fine bution of things into Material and Spiritual,
arts aim in common, invention is necessarily “ With these two classes of existences, he ob-
suhjected to the control of rules which it is the serves farther, “ history and philosophy aie
business of the philosopher to investigate. equally conversant; hut as for Imagination,
i( In farther justification of this arrangement, her imitations are entirely confined to the mate-
it may he remarked, that reason, in the course rial world ;—a circumstance, he adds, “ which
1 The latitude given by D’Alembert to the meaning of the word Poetry is a real and very important improvement on
Bacon, who restricts it to Fictitious History or Fables. {De Aug- Scient. Lib. ii. cap. i.) D’Alembert, on the other nan ,
employs it in its natural signification, as synonymous with invention or creation. “ La Pemture, la Sculpture, 1 A.rc i ec-
ture, la Poesie, la Musique, et leurs differentes divisions, composent la troisieme distribution generate qui nait de I Imagi¬
nation, et dont les parties sont comprises sous le nom de Beaux-Arts. On peut les rapporter tons a la 1 oesie, en prenant
ce mot dans sa signification naturelle, qui n’est autre chose qu’invention ou creation.” ,
2 In placing Ileason before Imagination, D’Alembert departs from the order in which these faculties^ are arranged by
Bacon. “ Si nous n’avons pas placd, comme lui, la Raison apres ITmagination, c’est que nous avons suivi dans le systeme
Encyclopedique, 1’ordre metaphysique des operations de 1’esprit, plutot que Pordre historique de ses progres depms la re¬
naissance des lettres (Disc. Prelim.) How far the motive here assigned for the change is valid, the reader will be enabled
to judge from the sequel of the above quotation.
PREFACE TO THE FIRST DISSERTATION.
5
conspires with the other arguments above stated,
in justifying Bacon for assigning to her the last
place in his enumeration of our intellectual fa¬
culties.” 1 Upon this subdivision he enlarges at
some length, and with considerable ingenuity;
but on the present occasion it would be quite
superfluous to follow him any farther, as more
than enough has been already quoted to enable
my readers to judge, whether the objections
which I am now to state to the foregoing ex¬
tracts he as sound and decisive as I apprehend
them to he.
Of these objections a very obvious one is sug¬
gested by a consideration, of which D’Alembert
himself has taken notice,—that the three facul¬
ties to which he refers the whole operations of
the understanding are perpetually blended to¬
gether in their actual exercise, insomuch that
there is scarcely a branch of human knowledge
which does not, in a greater or less degree,
furnish employment to them all. It may be
said, indeed, that some pursuits exercise and in¬
vigorate particular faculties more than others;
that the study of History, for example, al¬
though it may occasionally require the aid both
of Reason and of Imagination, yet chiefly fur¬
nishes occupation to the Memory; and that this
is sufficient to justify the logical division of our
mental powers as the ground-work of a corre¬
sponding Encyclopedical classification.2 This,
however, will be found more specious than solid.
In what respects is the faculty of Memory more
essentially necessary to the student of history
than to the philosopher or to the poet; and, on
the other hand, of what value, in the circle of the
sciences, would be a collection of historical de¬
tails, accumulated without discrimination, with¬
out a scrupulous examination of evidence, or
without any attempt to compare and to genera¬
lize ? For the cultivation of that species of his¬
tory, in particular, which alone deserves a place
in the Encyclopedical Tree, it may be justly af¬
firmed, that the rarest and most comprehensive
combination of all our mental gifts is indispen¬
sably requisite.
Another, and a still more formidable objec¬
tion to Bacon’s classification, may be derived
from the very imperfect and partial analysis of
the mind which it assumes as its basis. Why
were the powers of Abstraction and Generaliza¬
tion passed over in silence ?—powers which, ac¬
cording as they ara cultivated or neglected, con¬
stitute the most e»seTitia/ of all distinctions be¬
tween the intellectual cnaracters of individuals.
A corresponding distinction, too, not less im¬
portant, may be remarked among the objects of
human study, according as our aim is to treasure
up particular facts, or to establish general con¬
clusions. Does not this distinction mark out,
with greater precision, the limits which separate
philosophy from mere historical narrative, than
that which turns upon the different provinces of
Reason and of Memory ?
I shall only add one other criticism on this
celebrated enumeration, and that is, its want of
distinctness, in confounding together the Sciences
and the Arts under the same general titles.
Hence a variety of those capricious arrange¬
ments, which must immediately strike every
reader who follows Bacon through his details;—
the reference, for instance, of the mechanical
arts to the department of History; and conse¬
quently, according to his own analysis of the
Mind, the ultimate reference of these arts to the
faculty of Memory ; while at the same time, in
his tripartite division of the whole field of hu-
1 In this exclusive limitation of the province of Imagination to things Material and Sensible, D’Alembert has followed
the definition given by Descartes in his second Meditation : “ Imaginary nihil aliud est quam rei corporeaz fignram sen imagr-
nem contemplari a power of the mind, which (as I have elsewhere observed) appears to me to be most precisely ex¬
pressed in our language by the word Conception. The province assigned to Imagination by D’Alembert is more extensive
than this, for he ascribes to her also a creative and combining power ; but still his definition agrees with that of Descartes,
inasmuch as it excludes entirely from her dominion both the intellectual and the moral worlds.
2 I allude here to the following apology for Bacon, suggested by a very learned and judicious writer:—“ On a tail
cependant a Bacon quelques reproches assez fonde's. On a observe que sa classification des sciences repose sur une
distinction qui n’est pas rigoureuse, puisque la memoire, la raison, et 1’imagination concourent necessairement dans
chaque art, comme dans chaque science. Mais on pent rdpondre, que 1’un ou 1’autre de ces trois facultes, quoique secondee
par les deux autres, peut cependant jouer le role principal. En prenant la distinction de Bacon dans ce sens, sa classifica¬
tion reste exacte, et devient tres utile.”—(Degeraxdo, Hist. Comp. Tome I. p. 298.)
6
PRELIMINARY DISSERTATIONS.
man knowledge, the art of Poetry has one en¬
tire province allotted to itself.
These objections apply in common to Bacon
and to D’Alembert. That which follows has a
particular reference to a passage already cited
from the latter, where, by some false refinements
concerning the nature and functions of Imagina¬
tion, he has rendered the classification of his pre¬
decessor incomparably more indistinct and illo¬
gical than it seemed to he before.
That all the creations or new combinations of
Imagination, imply the previous process of de¬
composition or analysis, is abundantly manifest;
and, therefore, without departing from the com¬
mon and popular use of language, it may un¬
doubtedly be said, that the faculty of abstraction
is not less essential to the Poet, than to the Geo¬
meter and the Metaphysician.1 But this is not
the doctrine of D’Alembert. On the contrary,
he affirms, that Metaphysics and Geometry are,
of all the sciences connected with reason, those
in which Imagination has the greatest share ;—
an assertion which, it will not be disputed, has at
first sight somewhat of the air of a paradox ; and
which, on closer examination, will, I apprehend,
be found altogether inconsistent with fact. If
indeed D’Alembert had, in this instance, used,
as some writers have done, the word Imagina¬
tion as synonymous with Invention, I should not
have thought it worth while (at least so far as the
geometer is concerned) to dispute his proposi¬
tion. But that this was not the meaning annex¬
ed to it by the author, appears from a subsequent
clause, where he tells us, that the most refined
operations of reason, consisting in the creation
of generals which do not fall under the cogniz¬
ance of our senses, naturally led to the exercise of
Imagination. His doctrine, therefore, goes to the
identification of Imagination with Abstraction ;
two faculties so very different in the direction
which they give to our thoughts, that, according
to his own acknowledgment, the man who is
habitually occupied in exerting the one, seldom
fails to impair both his capacity and his relish
for the exercise of the other.
This identification of two faculties, so strong¬
ly contrasted in their characteristical features,
was least of all to he expected from a logician,
who had previously limited the province of Ima¬
gination to the imitation of material objects; a
limitation, it may be remarked in passing, which
is neither sanctioned by common use, nor by
just views of the philosophy of the mind. Upon
what ground can it be alleged, that Milton’s
portrait of Satan’s intellectual and moral cha¬
racter was not the offspring of the same creative
faculty which gave birth to his Garden of Eden ?
After such a definition, however, it is difficult
to conceive, how so very acute a writer should
have referred to Imagination the abstractions
of the geometer and of the metaphysician; and
still more, that he should have attempted to
justify this reference, by observing, that these
abstractions do not fall under the cognisance of
the senses. My own opinion is, that, in the
composition of the whole passage, he had a
view to the unexpected parallel between Homer
and Archimedes, with which he meant, at the
close, to surprise his readers.
If the foregoing strictures be well-founded,
it seems to follow, not only that the attempt of
Bacon and of D’Alembert to classify the sciences
and arts according to a logical division of our
faculties, is altogether unsatisfactory; but that
every future attempt of the same kind may be
expected to be liable to similar objections. In
studying, indeed, the Theory of the Mind, it is
necessary to push our analysis as far as the
nature of the subject admits of; and, wherever
the thing is possible, to examine its constituent
principles separately and apart from each other:
but this consideration itself, when combined
with what was before stated on the endless
variety of forms in which they may be blended
1 This assertion must, however, be understood with some qualifications ; for, although the Poet, as well as the Geometer
and the Metaphysician, be perpetually called upon to decompose, by means of abstraction, the complicated objects of per¬
ception, it must not be concluded that the abstractions of all the three are exactly of the same kind. Those of the Poet
amount to nothing more than to a separation into parts of the realities presented to his senses ; which separation is only a
preliminary step to a subsequent recomposition into new and ideal forms of the things abstracted ; whereas the abstractions
of the Metaphysician and of the Geometer form the very objects of their respective sciences.
PREFACE TO THE FIRST DISSERTATION.
7
together in our various intellectual pursuits, is
sufficient to show how ill adapted such an ana¬
lysis must for ever remain to serve as the basis
of an Encyclopedical distribution.1
The circumstance to which this part of Ba¬
con’s philosophy is chiefly indebted for its po¬
pularity, is the specious simplicity and compre¬
hensiveness of the distribution itself;—not the
soundness of the logical views by which it was
suggested. That all our intellectual pursuits
may be referred to one or other of these three
heads, History, Philosophy, and Poetry, may
undoubtedly be said with considerable plausi¬
bility ;—the word History being understood to
comprehend all our knowledge of particular
facts and particular events; the word Philoso¬
phy, all the general conclusions or laws inferred
from these particulars by induction; and the
word Poetry, all the arts addressed to the ima¬
gination. Not that the enumeration, even with
the help of this comment, can be considered as
complete; for, to pass over entirely the other
objections already stated, under which of these
three heads shall we arrange the various branches
of pure mathematics ?
Are we therefore to conclude, that the magni¬
ficent design, conceived by Bacon, of enumerat¬
ing, defining, and classifying the multifarious
objects of human knowledge;—a design, on the
successful accomplishment of which he himself
believed that the advancement of the sciences
essentially depended;—Are we to conclude,
that this design was nothing more than the
abortive offspring of a warm imagination, un¬
susceptible of any useful application to enlight¬
en the mind, or to accelerate its progress ?
My own idea is widely different. The design
was, in every respect, worthy of the sublime
genius by which it was formed. Nor does it
follow, because the execution was imperfect?
that the attempt has been attended with no ad¬
vantage. At the period when Bacon wrote, it
was of much more consequence to exhibit to the
learned a comprehensive sketch, than an ac¬
curate survey of the intellectual world;—such
a sketch as, by pointing out to those whose
views had been hitherto confined within the
limits of particular regions, the relative positions
and bearings of their respective districts as
parts of one great whole, might invite them all,
for the common benefit, to a reciprocal exchange
of their local riches. The societies or acade¬
mies which, soon after, sprung up in different
countries of Europe, for the avowed purpose of
contributing to the general mass of information,
by the collection of insulated facts, conjectures,
and queries, afford sufficient proof, that the anti¬
cipations of Bacon were not, in this instance,
altogether chimerical.
In examining the details of Bacon’s survey, it
is impossible not to be struck (more especially
when we reflect on the state of learning two
hundred years ago) with the minuteness of his
information, as well as with the extent of his
views; or to forbear admiring his sagacity in
pointing out, to future adventurers, the unknown
tracks still left to be explored by human cu¬
riosity If his classifications be sometimes arti¬
ficial and arbitrary, they have at least the merit
of including, under one head or another, every
particular of importance; and of exhibiting these
particulars with a degree of method and of ap¬
parent connection, which, if it does not always
satisfy the judgment, never fails to interest the
fancy, and to lay hold of the memory. Nor
must it be forgotten, to the glory of his genius,
that what he failed to accomplish remains to
this day a desideratum in science ;—that the in¬
tellectual chart delineated by him is, Avith all its
imperfections, the only one of which modern
philosophy has yet to boast;—and that the
united talents of D’Alembert and of Diderot,
1 In justice to the authors of the Encyclopedical Tree prefixed to the French Dictionary, it ought to be observed, that
it is spoken of by D’Alembert, in his Preliminary Discourse, with the utmost modesty and diffidence ; and that he has ex-
pressed, not only his own conviction, but that of his colleague, of the impossibility of executing such a task in a manner
likely to satisfy the public. “ Nous sommes trop convaincus de I’arbitraire qui regnera toujours dans une pareille division,
pour croire que notre systeme soit 1’unique ou le meilleur ; il nous suffira que notre travail ne soit pas entierement desap-
prouve par les bons esprits.” And, some pages afterwards, “ Si le public eclaire donne son approbation a ces changemens,
elle sera la recompense de notre docilite ; et s’il ne les approuve pas, nous n’en serons que plus convaincus de 1’impossi-
bilitd de former un Arbre Encyclopedique qui soit au gre de tout le monde.”
8
PRELIMINARY DISSERTATIONS.
aided by all the lights of the eighteenth century,
have been able to add but little to what Bacon
performed.
After the foregoing observations, it will not
he expected that an attempt is to he made, in
the following Essay, to solve a problem which
has so recently baffled the powers of these
eminent writers, and which will probably long
continue to exercise the ingenuity of our suc¬
cessors. How much remains to he previously
done for the improvement of that part of Logic,
whose province it is to fix the limits by which
contiguous departments of study are defined
and separated! And how many unsuspected
affinities may he reasonably presumed to exist
among sciences, which, to our circumscribed
views, appear at present the most alien from
each other ! The abstract geometry of Apol¬
lonius and Archimedes was found, after an in¬
terval of two thousand years, to furnish a torch
to the physical inquiries of Newton; while, in
the further progress of knowledge, the Etymo¬
logy of Languages has been happily employed
to fill up the chasms of Ancient History; and
the conclusions of Comparative Anatomy, to il¬
lustrate the Theory of the Earth. For my own
part, even if the task were executed with the
most complete success, I should be strongly in¬
clined to think, that its appropriate place in an
Encyclopaedia would be as a branch of the article
on Logic;—certainly not as an exordium to the
Preliminary Discourse; the enlarged and re¬
fined views which it necessarily presupposes be¬
ing peculiarly unsuitable to that part of the work
which may be expected, in the first instance, to
attract the curiosity of every reader.
Before concluding this preface, I shall sub¬
join a few slight strictures on a very concise and
comprehensive division of the objects of Human
Knowledge, proposed by Mr Locke, as the ba¬
sis of a new classification of the sciences. Al¬
though I do not know that any attempt has ever
been made to follow out in detail the general
idea, yet the repeated approbation which has
been lately bestowed on a division essentially
the same, by several writers of the highest rank,
renders it in some measure necessary, on the
present occasion, to consider how far it is found¬
ed on just principles; more especially as it is
completely at variance not only with the lan¬
guage and arrangement adopted in these preli¬
minary essays, but with the whole of that plan on
which the original projectors, as well as the con-
tinuators, of the Encyclopcedia Britannica, ap¬
pear to have proceeded. These strictures will,
at the same time, afford an additional proof of
the difficulty, or rather of the impossibility, in
the actual state of logical science, of solving
this great problem, in a manner calculated to
unite the general suffrages of philosophers.
“ All that can fall,” says Mr Locke, <c with¬
in the compass of Human Understanding being
either, first, The nature of things as they are in
themselves, their relations, and their manner of
operation; or, secondly, That which man him¬
self ought to do as a rational and voluntary
agent, for the attainment of any end, especially
happiness; or, thirdly, The ways and means
whereby the knowledge of both the one and the
other of these is attained and communicated; I
think science may be divided properly into these
three sorts:
“ 1. Guff/xt], or Natural Philosophy. The end
of this is bare speculative truth ; and whatsoever
can afford the mind of man any such, falls under
this branch, whether it be God himself, angels,
spirits, bodies, or any of their affections, as num¬
ber and figure, &c.
“ 2. ITgaxmjj, The skill of right applying our
own powers and actions for the attainment of
things good and useful. The most considerable
under this head is Ethics^ which is the seeking
out those rules and measures of human actions
which lead to happiness, and the means to prac¬
tise them. The end of this is not bare specula¬
tion, but right, and a conduct suitable to it.1
“ 3. Sjj/As/wr/xj), or the doctrine of signs, the
most usual whereof being words, it is aptly
enough termed also Aoyari, Logic. The business
of this is to consider the nature of signs the
1 From this definition it appears, that as Locke included under the title of Physics, not only Natural Philosophy, pro¬
perly so called, but Natural Theology, and the Philosophy of the Human Mind, so he meant to refer to the head of Practics,
not only Ethics, but all the various Arts of life, both mechanical and liberal.
PREFACE TO THE FIRST DISSERTATION.
9
mind makes use of for the understanding of
things, or conveying its knowledge to others.
<c This seems to me,” continues Mr Locke,
“ the first and most general, as well as natural, di¬
vision of the ohjects of our understanding; for a
man can employ his thoughts about nothing hut
either the contemplation of things themselves,
for the discovery of truth; or about the things
in his own power, which are his own actions,
for the attainment of his own ends; or the
signs the mind makes use of, both in one and
the other, and the right ordering of them for
its clearer information. All which three, viz.
things as they are in themselves knowahle;
actions as they depend on us, in order to hap¬
piness ; and the right use of signs, in order to
knowledge; being toto ccelo different, they seem¬
ed to me to he the three great provinces of the
intellectual world, wholly separate and distinct
one from another.”1
From the manner in which Mr Locke ex¬
presses himself in the above quotation, he ap¬
pears evidently to have considered the division
proposed in it as an original idea of his own;
and yet the truth is, that it coincides exactly
with what was generally adopted by the philo¬
sophers of ancient Greece. “ The ancient
Greek Philosophy,” says Mr Smith, “ was divid¬
ed into three great branches, Physics, or Natural
Philosophy; Ethics, or Moral Philosophy; and
Logic. This general division,” he adds, “ seems
perfectly agreeable to the nature of things.” Mr
Smith afterwards observes, in strict conformity
to Locke’s definitions (of which, however, he
seems to have had no recollection when he
wrote this passage), “ That, as the human
mind and the Deity, in whatever their essence
may he supposed to consist, are parts of the
great system of the universe, and parts, too,
productive of the most important effects, what¬
ever was taught in the ancient schools of Greece,
concerning their nature, made a part of the sys¬
tem of physics.”2 *
Dr Campbell, in his Philosophy of Rhetoric
has borrowed from the Grecian schools the
same very extensive use of the words physics
and physiology, which he employs as synonymous
terms; comprehending under this title “ not
merely Natural History, Astronomy, Geography,
Mechanics, Optics, Hydrostatics, Meteorology,
Medicine, Chemistry, hut also Natural Theology
and Psychology, which,” he observes, “ have
been, in his opinion, most unnaturally disjoined
from Physiology by philosophers.” “ Spirit,” he
adds, “ which here comprises only the Supreme
Being and the human soul, is surely as much in¬
cluded under the notion of natural object as body
is; and is knowahle to the philosopher purely in
the same way, by observation and experience.”5
A similar train of thinking led the late cele¬
brated M. Turgot to comprehend under the
name of Physics, not only Natural Philosophy
(as that phrase is understood by the Newtonians),
but Metaphysics, Logic, and even History.4
Notwithstanding all this weight of authority,
it is difficult to reconcile one’s self to an arrange¬
ment which, while it classes with Astronomy,
with Mechanics, with Optics, and with Hy¬
drostatics, the strikingly contrasted studies of
Natural Theology and of the Philosophy of the
Human Mind, disunites from the two last the
far more congenial sciences of Ethics and of
Logic. The human mind, it is true, as well as
the material world which surrounds it, forms
a part of the great system of the Universe; hut
is it possible to conceive two parts of the same
whole more completely dissimilar, or rather
more diametrically opposite, in all their charac-
teristical attributes ? Is not the one the appro¬
priate field and province of observation,—a power
1 See the concluding chapter of the Essay on Human Understanding, entitled, “ Of the Division of the Sciences.”
J Wealth of Nations, Book v. chap. i.
* Philosophy of Rhetoric, Book i. chap. v. Part iii. § 1.
4 “ Sous le nom de sciences physiques je comprends la logique, qui est la connoissance des operations de notre esprit et
de la generation de nos idees; la metaphysique, qui s’occupe de la nature et de 1’origine des etres ; et enfin la physique, pro-
prement dite, qui observe Paction mutuelle des corps les uns sur les autres, et les causes et Penchainement des phe'nomenes
sensibles. On pourroit y ajouter Vhistoire."—(Qduvres de Turgot, Tome II. pp. 284, 285.)
In the year 1795, a quarto volume was published at Bath, entitled Intellectual Physics. It consists entirely of speculations
concerning the human mind, and is by no means destitute of merit. The publication was anonymous ; but I have reason
to believe that the author was the late well-known Governor Pownall.
DISS. I. PART I. B
10
PRELIMINARY DISSERTATIONS.
habitually awake to all the perceptions and im¬
pressions of the bodily organs ? And does not
the other fall exclusively under the cognisance
of reflectim ;—an operation which inverts all the
ordinary habits of the understanding, abstract¬
ing the thoughts from every sensible object,
and even striving to abstract them from every
sensible image ? What abuse of language can
be greater, than to apply a common name to
departments of knowledge which invite the
curiosity in directions precisely contrary, and
which tend to form intellectual talents, which,
if not altogether incompatible, are certainly not
often found united in the same individual?
The word Physics, in particular, which, in our
language, long and constant use has restricted
to the phenomena of Matter, cannot fail to strike
every ear as anomalously, and therefore illogical-
ly, applied, when extended to those of Thought
and of Consciousness.
Nor let it be imagined that these observations
assume any particular theory about the nature
or essence of Mind. Whether we adopt, on this
point, the language of the Materialists, or that
of their opponents, it is a proposition equally
certain and equally indisputable, that the phe¬
nomena of Mind and those of Matter, as far as
they come under the cognisance of our faculties,
appear to be more completely heterogeneous
than any other classes of facts within the circle
of our knowledge ; and that the sources of our
information concerning them are in every re¬
spect so radically different, that nothing is more
carefully to be avoided, in the study of either,
than an attempt to assimilate them, by means
of analogical or metaphorical terms, applied to
both in common. In those inquiries, above all,
where we have occasion to consider Matter and
Mind as conspiring to produce the same joint
effects (in the constitution, for example, of our
own compounded frame), it becomes more pe¬
culiarly necessary to keep constantly in view
the distinct province of each, and to remember,
that the business of philosophy is not to resolve
the phenomena of the one into those of the
other, but merely to ascertain the general laws
which regulate their mutual connection. Mat¬
ter and Mind, therefore, it should seem, are the
two most general heads which ought to form
the ground-work of an Encyclopedical classifi¬
cation of the sciences and arts. No branch of
human knowledge, no work of human skill, can
be mentioned, which does not obviously fall un¬
der the former head or the latter.
Agreeably to this twofold classification of the
sciences and arts, it is proposed, in the follow¬
ing introductory Essays, to exhibit a rapid
sketch of the progress made since the revival of
letters: First, in those branches of knowledge
which relate to Mind; and, secondly, in those
which relate to Matter. D’Alembert, in his
Preliminary Discourse, has boldly attempted to
embrace both subjects in one magnificent de¬
sign ; and never, certainly, was there a single
mind more equal to such an undertaking. The
historical outline which he has there traced
forms by far the most valuable portion of that
performance, and will for ever remain a proud
monument to the depth, to the comprehensive¬
ness, and to the singular versatility of his genius.
In the present state of science, however, it has
been apprehended, that, by dividing so great a
work among different hands, something might
perhaps be gained, if not in point of reputation
to the authors, at least in point of instruction
to their readers. This division of labour was,
indeed, in some measure, rendered necessary
(independently of all other considerations), by
the important accessions which mathematics
and physics have received since D’Alembert’s
time;—by the innumerable improvements which
the spirit of mercantile speculation, and the
rivalship of commercial nations, have introduced
into the mechanical arts;—and, above all, by
the rapid succession of chemical discoveries,
which commences with the researches of Black
and of Lavoisier. The part of this task which
has fallen to my share is certainly, upon the
whole, the least splendid in the results which it
has to record; but I am not without hopes, that
this disadvantage may be partly compensated
by its closer connection with (what ought to
be the ultimate end of all our pursuits) the in¬
tellectual and moral improvement of the spe¬
cies.
I am, at the same time, well aware that, in
proportion as this last consideration increases
the importance, it adds to the difficulty of my
PREFACE TO THE FIRST DISSERTATION.
11
undertaking. It is chiefly in judging of ques¬
tions “ coming home to their business and bo¬
soms,” that casual associations lead mankind
astray; and of such associations how incalcu¬
lable is the number arising from false systems of
religion, oppressive forms of government, and
absurd plans of education! The consequence
is, that while the physical and mathematical dis¬
coveries of former ages present themselves to
the hand of the historian, like masses of pure
and native gold, the truths which we are here
in quest of may he compared to iron, which, al¬
though at once the most necessary and the most
widely diffused of all the metals, commonly rer
quires a discriminating eye to detect its exist¬
ence, and a tedious, as well as nice process, to
extract it from the ore.
To the same circumstance it is owing, that
improvements in Moral and in Political Science
do not strike the imagination with nearly so
great force as the discoveries of the Mathemati¬
cian or of the Chemist. When an inveterate
prejudice is destroyed by extirpating the casual
associations on which it was grafted, how power¬
ful is the new impulse given to the intellectual
faculties of man ! Yet how slow and silent the
process by which the effect is accomplished!
Were it not, indeed, for a certain class of learned
authors, who, from time to time, heave the log
into the deep, we should hardly believe that the
reason of the species is progressive. In this re¬
spect, the religious and academical establish¬
ments in some parts of Europe are not without
their use to the Historian of the Human Mind.
Immoveahly moored to the same station by the
strength of their cables, and the weight of their
anchors, they enable him to measure the rapi¬
dity of the current by which the rest of the
world are borne along.
This, too, is remarkable in the history of our
prejudices; that, as soon as the film falls from
the intellectual eye, we are apt to lose all recol¬
lection of our former blindness. Like the fan¬
tastic and giant shapes which, in a thick fog, the
imagination lends to a block of stone, or to the
stump of a tree, they produce, while the illusion
lasts, the same effect with truths and realities;
hut the moment the eye has caught the exact
form and dimensions of its object, the spell is
broken for ever; nor can any effort of thought
again conjure up the spectres which have va¬
nished.
As to the subdivisions of which the sciences
of Matter and of Mind are susceptible, I have
already said, that this is not the proper place for
entering into any discussion concerning them.
The passages above quoted from D’Alembert,
from Locke, and from Smith, are sufficient to
show how little probability there is, in the actual
state of Logical Science, of uniting the opinions
of the learned in favour of any one scheme of
partition. To prefix, therefore, such a scheme
to a work which is professedly to he carried on
by a set of unconnected writers, would he equal¬
ly presumptuous and useless; and, on the most
favourable supposition, could tend only to fetter,
by means of dubious definitions, the subsequent
freedom of thought and of expression. The ex¬
ample of the French Encyclopedie cannot here he
justly alleged as a precedent. The preliminary
pages by which it is introduced were written by
the two persons who projected the whole plan,
and who considered themselves as responsible,
not only for their own admirable articles, hut
for the general conduct of the execution; where¬
as, on the present occasion, a porch was to he
adapted to an irregular edifice, reared, at differ¬
ent periods, by different architects. It seemed,
accordingly, most advisable to avoid, as much
as possible, in these Introductory Essays, all in¬
novations in language, and, in describing the
different arts and sciences, to follow scrupulous¬
ly the prevailing and most intelligible phrase-
ology. The task of defining them, with a greater
degree of precision, properly devolves upon those
to whose province it belongs, in the progress of
the work, to unfold in detail their elementary
principles.
The sciences to which I mean to confine my
observations are Metaphysics, Ethics, and Poli¬
tical Philosophy; understanding, by Metaphy¬
sics, not the Ontology and Pneumatology of the
schools, hut the inductive Philosophy of the
Human Mind; and limiting the phrase Political
Philosophy almost exclusively to the modern
science of Political Economy; or (to express
myself in terms at once more comprehensive
and more precise) to that branch of the theory
12
PRELIMINARY DISSERTATIONS.
of legislation which, according to Bacon’s defi¬
nition, aims to ascertain those “ Leges legum,
ex quibus informatio peti potest quid in singulis
legibus hene aut perperam positum aut constitu-
tum sit.” The close affinity between these three
departments of knowledge, and the easy transi¬
tions by which the curiosity is invited from the
study of any one of them to that of the other
two, wall sufficiently appear from the following
Historical Review.
DISSERTATION FIRST
PART FIRST.
In the following Historical and Critical
Sketches, it has been judged proper by the dif¬
ferent writers, to confine their views entirely to
the period which has elapsed since the revival of
letters. To have extended their retrospects to
the ancient world would have crowded too great
a multiplicity of objects into the limited canvas
on which they had to work. For my own part,
I might, perhaps with still greater propriety,
have confined myself exclusively to the two last
centuries; as the Sciences of which I am to
treat, present but little matter for useful remark,
prior to the time of Lord Bacon. I shall make
no apology, however, for devoting, in the first
place, a few pages to some observations of a more
general nature, and to some scanty gleanings of
literary detail, bearing more or less directly on
my principal design.
On this occasion, as well as in the sequel of
my Discourse, I shall avoid, as far as is consist¬
ent with distinctness and perspicuity, the mi¬
nuteness of the mere bibliographer; and, instead
of attempting to amuse my readers with a series
of critical epigrams, or to dazzle them with a
rapid succession of evanescent portraits, shall
study to fix their attention on those great lights
of the world by whom the torch of science has
been successively seized and transmitted.1 It
is, in fact, such leading characters alone which
furnish matter for philosophical history. To enu¬
merate the names or the labours of obscure or
even secondary authors, whatever amusement it
might afford to men of curious erudition, would
contribute but little to illustrate the origin and
filiation of consecutive systems, or the gradual
developement and progress of the human mind.
1 I have ventured here to combine a scriptural expression with an allusion of Plato’s to a Grecian game;—an allusion which,
in his writings, is finely and pathetically applied to the rapid succession of generations, through which the continuity of
human life is maintained from age to age; and which are perpetually transferring from hand to hand the concerns and du¬
ties of this fleeting scene, revvaim; T£ xa) ixrgsQovns ‘raT'Sas, xa.6a‘jrtt> tou [iiov oraga'didovrii aXXoi; aXXaiv.—(Plato, Leg.
lib. vi.)
Et quasi cursores vital lampada tradunt.—Lucret.
14
PRELIMINARY DISSERTATIONS.
CHAPTER I.
FROM THE REVIVAL OF LETTERS TO THE PUBLICATION OF BACON’S PHILOSOPHICAL
WORKS.
The long interval, commonly known by the
name of the middle ages, which immediately pre¬
ceded the revival of letters in the western part
of Europe, forms the most melancholy blank
which occurs, from the first dawn of recorded
civilisation, in the intellectual and moral his¬
tory of the human race. In one point of view
alone, the recollection of it is not altogether un¬
pleasing, inasmuch as, by the proof it exhibits
of the inseparable connection between ignorance
and prejudice on the one hand, and vice, mi¬
sery, and slavery on the other, it affords, in
conjunction with other causes, which will after¬
wards fall under our review, some security
against any future recurrence of a similar cala¬
mity.
It would furnish a very interesting and in¬
structive subject of speculation, to record and
to illustrate (with the spirit, however, rather of
a philosopher than of an antiquary), the various
abortive efforts, which, during this protracted
and seemingly hopeless period of a thousand
years, were made by enlightened individuals, to
impart to their contemporaries the fruits of their
own acquirements. For in no one age from its
commencement to its close, does the continuity of
knowledge (if I may borrow an expression of Mr
Harris), seem to have been entirely interrupted:
“ There was always a faint twilight, like that
auspicious gleam which, in a summer’s night,
fills up the interval between the setting and the
rising sun.”1 On the present occasion, I shall
content myself with remarking the important
effects produced by the numerous monastic esta¬
blishments all over the Christian world, in pre¬
serving, amidst the general wreck, the inesti¬
mable remains of Greek and Roman refinement,
and in keeping alive, during so many centuries,
those scattered sparks of truth and of science,
which were afterwards to kindle into so bright
a flame. I mention this particularly, because, in
our zeal against the vices and corruptions of the
Romish church, we are too apt to forget, how
deeply wre are indebted to its superstitious and
apparently useless foundations, for the most pre¬
cious advantages that we now enjoy.
The study of the Roman Law, which, from a
variety of causes, natural as well as accidental,
became, in the course of the twelfth century, an
object of general pursuit, shot a strong and aus¬
picious ray of intellectual light across the sur¬
rounding darkness. No study could then have
been presented to the curiosity of men, more
happily adapted to improve their taste, to enlarge
their views, or to invigorate their reasoning
powers; and although, in the first instance,
prosecuted merely as the object of a weak and
undistinguishing idolatry, it nevertheless con¬
ducted the student to the very confines of ethical
as well as of political speculation ; and served, in
the meantime, as a substitute of no inconsider¬
able value for both these sciences. According¬
ly we find that, while in its immediate effects it
powerfully contributed, wherever it struck its
roots, by ameliorating and systematizing the ad¬
ministration of justice, to accelerate the progress
of order and of civilization, it afterwards furnish¬
ed, in the further career of human advancement,
the parent stock on which were grafted the first
rudiments of pure ethics and of liberal politics
taught in modern times. I need scarcely add,
that I allude to the systems of natural jurispru-
Philological Inquiries, Part HI. chap. i.
i
DISSERTATION FIRST.
15
dence compiled by Grotius and bis successors;—
systems which, for a hundred and fifty years,
engrossed all the learned industry of the most
enlightened part of Europe; and which, how¬
ever unpromising in their first aspect, were des¬
tined, in the last result, to prepare the way for
that never to he forgotten change in the literary
taste of the eighteenth century, c< which has
everywhere turned the spirit of philosophical
inquiry from frivolous or abstruse speculations,
to the business and affairs of men.”1
The revival of letters may he considered as
coeval with the fall of the Eastern empire, to¬
wards the close of the fifteenth century. In con¬
sequence of this event, a number of learned
Greeks took refuge in Italy, where the taste for
literature already introduced by Dante, Petrarch,
and Boccacio, together with the liberal patro¬
nage of the illustrious House of Medicis, secu¬
red them a welcome reception. A knowledge of
the Greek tongue soon became fashionable; and
the learned, encouraged by the rapid diffusion
which the art of printing now gave to their
labours, vied with each other in rendering the
Greek authors accessible, by means of Latin
translations, to a still wider circle of readers.
For a long time, indeed, after the era just
mentioned, the progress of useful knowledge
was extremely slow. The passion for logical
disputation was succeeded by an unbounded ad¬
miration for the wisdom of antiquity; and in
proportion as the pedantry of the schools disap¬
peared in the universities, that of erudition and
philology occupied its place.
Meanwhile, an important advantage was gain¬
ed in the immense stock of materials which the
ancient authors supplied to the reflections of
speculative men; and which, although frequent¬
ly accumulated with little discrimination or pro¬
fit, were much more favourable to the develope-
ment of taste and of genius than the unsubstan¬
tial subtleties of ontology or of dialectics. By
such studies were formed Erasmus,2 Ludovicus
Vives,3 Sir Thomas More,4 and many other ac¬
complished scholars of a similar character, who,
if they do not rank in the same line with the
daring reformers by whom the errors of the
Catholic church were openly assailed, certainly
exhibit a very striking contrast to the barbarous
and unenlightened writers of the preceding age.
The Protestant Reformation, which followed
immediately after, was itself one of the natural
consequences of the revival of letters, and of the
invention of printing. But although, in one
1 Dr Robertson, from whom I quote these words, has mentioned this change as the glory of the present age, meaning, I
presume, the period which has elapsed since the time of Montesquieu. By what steps the philosophy to which he alludes
took its rise from the systems of jurisprudence previously in fashion, will appear in the sequel of this Discourse.
2 The writings of Erasmus probably contributed still more than those of Luther himself to the progress of the Reforma¬
tion among men of education and taste; but, without the co-operation of bolder and more decided characters than his, little
would to this day have been effected in Europe among the lower orders. “ Erasmus imagined,” as is observed by his bio¬
grapher, “ that at length, by training up youth in learning and useful knowledge, those religious improvements would
gradually be brought about, which the Princes, the Prelates, and the Divines of his days could not be persuaded to admit
or to tolerate.” (Jortin, p. 279.) In yielding, however, to this pleasing expectation, Erasmus must have flattered himself
with the hope, not only of a perfect freedom of literary discussion, but of such reforms in the prevailing modes of instruc¬
tion, as would give complete scope to the energies of the human mind ;—for, where books and teachers are subjected to the
censorship of those who are hostile to the dissemination of truth, they become the most powerful of all auxiliaries to the
authority of established errors.
It was long a proverbial saying among the ecclesiastics of the Romish church, that “ Erasmus laid the egg, and Luther
hatched itand there is more truth in the remark, than in most of their sarcasms on the same subject.
3 Ludovicus Vives was a learned Spaniard, intimately connected both with Erasmus and More ; with the former of
whom he lived for some time at Louvain, “ where they both promoted literature as much as they could, though not with¬
out great opposition from some of the divines.”—Jortin, p. 255.
“ He was invited into England by Wolsey, in 1523; and coming to Oxford, he read the Cardinal’s lecture of Humanity,
and also lectures of Civil Law, which Henry VIII. and his Queen, Catherine, did him the honour of attending—(Ibid. p.
207.) He died at Bruges in 1554.
In point of good sense and acuteness, wherever he treats of philosophical questions, he yields to none of his contempo¬
raries ; and in some of his anticipations of the future progress of science, he discovers a mind more comprehensive and
sagacious than any of them. Erasmus appears, from a letter of his to Budseus, dated in 1521, to have foreseen the bn -
liant career which Vives, then a very young man, was about to run. “ Vives in stadio literario, non minus feliciter quam
gnaviter decertat, et si satis ingenium hominis novi, non conquiescet, donee omnes a tergo reliquerit.”—I or this letter ( le
whole of which is peculiarly interesting, as it contains a character of Sir Thomas More, and an account of the extraordinary
accomplishments of his daughters), See Jortin’s Life of Erasmus, Vol. II. p. 366. et seq.
4 See Note A.
16
PRELIMINARY DISSERTATIONS.
point of view, only an effect, it is not, on the
present occasion, less entitled to notice than the
causes by which, it was produced.
The renunciation, in a great part of Europe,
of theological opinions so long consecrated by
time, and the adoption of a creed more pure in
its principles and more liberal in its spirit, could
not fail to encourage, on all other subjects, a
congenial freedom of inquiry. These circum¬
stances operated still more directly and power¬
fully, by their influence, in undermining the au¬
thority of Aristotle;—an authority which foi
many years was scarcely inferior in the schools
to that of the Scriptures; and which, in some
Universities, was supported by statutes, requir¬
ing the teachers to promise upon oath, that in
their public lectures, they would follow no other
guide.
Luther,1 who was perfectly aware of the cor¬
ruptions which the Romish church had contriv¬
ed to connect with their veneration for the Sta-
girite,2 not only threw off the yoke himself, but,
in various parts of his writings, speaks of Aris¬
totle with the most unbecoming asperity and
contempt.3 In one very remarkable passage,
he asserts, that the study of Aristotle was wholly
useless, not only in Theology, but in Natural
Philosophy. “ What does it contribute,” he
asks, “ to the knowledge of things, to trifle and
cavil in language conceived and prescribed by
Aristotle, concerning matter, form, motion, and
time?”4 The same freedom of thought on to¬
pics not strictly theological, formed a prominent
feature in the character of Calvin. A curious
instance of it occurs in one of his letters, where
he discusses an ethical question of no small mo¬
ment in the science of political economy;—
“ How far it is consistent with morality to ac¬
cept of interest for a pecuniary loan ?” On this
question, which, even in Protestant countries,
continued, till a very recent period, to divide the
opinions both of divines and lawyers, Calvin
treats the authority of Aristotle and that of the
church with equal disregard. To the former he
opposes a close and logical argument, not un¬
worthy of Mr Bentham. To the latter he replies,
by showing, that the Mosaic law on this point
was not a moral but a municipal prohibition;
a prohibition not to be judged of from any par¬
ticular text of Scripture, but upon the principles
of natural equity.5 The example of these two
Fathers of the Reformation would probably have
been followed by consequences still greater and
more immediate, if Melanchthon had not unfor¬
tunately given the sanction of his name to the
doctrines of the Peripatetic school:6 but still,
among the Reformers in general, the credit of
these doctrines gradually declined, and a spirit
of research and of improvement prevailed.
The invention of printing, which took place
1 Born 1483, died 1546. . . .
2 In one of his letters he writes thus : “ Ego simpliciter credo, quod impossihue sit ecclesiain reiormari, nisi tunnitus
canones, decretales, scholastica theologia, philosophia, logica, ut nunc habentur, eradicentur, etalia instituantur.”—Bruck-
Eri Hitt Crit. Phil. Tom. IV. p. 95.
3 For a specimen of Luther’s scurrilitj against Aristotle, see Bayle, Art. Luther, Note HH.
In Luther’s Colloquia Mensalia we are told, that “ he abhorred the Schoolmen, and called them sophistical locusts, cater¬
pillars, frogs, and lice.” From the same work we learn, that “ he hated Aristotle, but highly esteemed Cicero, as a wise
and a good man.”—See Jortin’s £,i/e of EmswMs, p. 121. _ ...
4 u Nihil adjumenti ex ipso haberi posse non solum ad theologiam seu sacras literas, verum etiam ad ipsam naturalem
philosophiam. Quid enim juvet ad rerum cognitionem, si de materia, forma, motu, tempore, nugari et cavillari queas ver¬
bis ab Aristotele conceptis et prsescriptis ?”—Bruck. Hist. Phil. Tom. IV. p. 101.
The following passage to the same purpose is quoted by Bayle: “ Non mihi persuadebitis, philosophiam esse garruhta-
tem illam de materia, motu, infinite, loco, vacuo, tempore, quae fere in Aristotele sola discimus, talia quae nec intellectum,
nec affectum, nec communes hominum mores quidquam juvent; tantum contentionibus serendis, seminandisque idonea.”—.
Bayle, Art. Luther, Note HH.
I borrow from Bayle another short extract from Luther: “ Nihil ita ardet animus, quam histrionem ilium (Aristotelem),
qui tarn vere Grseca larva ecclesiam lusit, multis revelare, ignominiamque ejus cunctis ostendere, si otium esset. Habeo
in manus commentariolos in 1. Physicorum, quibus fabulam Aristsei denuo agere statui in meum istum Protea (Aristotelem).
Pars crucis meae vel maxima est, quod videre cogor fratrum optima ingenia, bonis studiis nata, in istis coems vitam agere,
et operam perdere.”—Ibid.
That Luther was deeply skilled in the scholastic philosophy we learn from very high authority, that of Melanchthon;
who tells us farther, that he was a strenuous partizan of the sect of Nominalists, or, as they were then generally called,
Terminists Bruck. Tom. IV. pp. 93, 94, et seq.
* See Note B. .....
6 “ Et Melanchthoni quidem prsecipue debetur conservatio philosophise Aristotelicae in academiis protestantium. Scripsit
is compendia plerarumque disciplinarum philosophise Aristotelicse, quse in Academiis diu regnarunt.”—Heineccxi, Elem.
Hist. Phil. § ciii. See also Bayle’s Dictionary, Art. Melanchthon.
DISSERTATION FIRST.
17
very nearly at the same time with the fall of
the Eastern Empire, besides adding greatly to
the efficacy of the causes above-mentioned, must
have been attended with very important effects
of its own, on the progress of the human mind.
For us who have been accustomed, from our in¬
fancy, to the use of hooks, it is not easy to form
an adequate idea of the disadvantages which
those laboured under, who had to acquire the
whole of their knowledge through the medium
of universities and schools;—blindly devoted as
the generality of students must then have been
to the peculiar opinions of the teacher who first
unfolded to their curiosity the treasures of lite¬
rature and the wonders of science. Thus error
was perpetuated; and, instead of yielding to
time, acquired additional influence in each suc¬
cessive generation.* In modern times, this in¬
fluence of names is, comparatively speaking, at
an end. The object of a public teacher is no
longer to inculcate a particular system of dog¬
mas, but to prepare his pupils for exercising
their own judgments; to exhibit to them an
outline of the different sciences, and to suggest
subjects for their future examination. The few
attempts to establish schools and to found sects,
have all, after perhaps a temporary success,
proved abortive. Their effect, too, during their
short continuance, has been perfectly the reverse
of that of the schools of antiquity; for where¬
as these were instrumental, on many occasions,
in establishing and diffusing error in the world,
the founders of our modern sects, by mixing up
important truths with their own peculiar tenets,
and by disguising them under the garb of a tech¬
nical phraseology, have fostered such prejudices
against themselves, as have blinded the public
mind to all the lights they were able to commu¬
nicate. Of this remark a melancholy illustra¬
tion occurs, as M. Turgot long ago predicted,
in the case of the French Economists; and
many examples of a similar import might be pro¬
duced from the history of science in our coun¬
try; more particularly from the history of the va¬
rious medical and metaphysical schools which
successively rose and fell during the last century.
With the circumstances already suggested, as
conspiring to accelerate the progress of know¬
ledge, another has co-operated very extensively
and powerfully; the rise of the lower orders in
the different countries of Europe,—in conse¬
quence partly of the enlargement of commerce,
and partly of the efforts of the Sovereigns to re¬
duce the overgrown power of the feudal aristo¬
cracy.
Without this emancipation of the lower or¬
ders, and the gradual diffusion of wealth by
which it was accompanied, the advantages de¬
rived from the invention of printing would have
been extremely limited. A certain degree of
ease and independence is essentially requisite to
inspire men with the desire of knowledge, and
to afford the leisure necessary for acquiring it;
and it is only by the encouragement which such
a state of society presents to industry and ambi¬
tion, that the selfish passions of the multitude
can be interested in the intellectual improve¬
ment of their children. It is only, too, in such
a state of society, that education and books are
likely to increase the sum of human happiness;
for while these advantages are confined to one
privileged description of individuals, they but
furnish them with an additional engine for de¬
basing and misleading the minds of their infe¬
riors. To all which it may be added, that it is
chiefly by the shock and collision of different and
opposite prejudices, that truths are gradually
cleared from that admixture of error which they
have so strong a tendency to acquire, wherever
the course of public opinion is forcibly con-
1 It was in consequence of this mode of conducting education by means of oral instruction alone, that the different sects
of philosophy arose in ancient Greece; and it seems to have been with a view of counteracting the obvious inconveniences
resulting from them, that Socrates introduced his peculiar method of questioning, with an air of sceptical diffidence, those
whom he was anxious to instruct; so as to allow them, in forming their conclusions, the complete and unbiassed exercise
of their own reason. Such, at least, is the apology offered for the apparent indecision of the Academic school, by one of
its wisest as well as most eloquent adherents. “ As for other sects,” says Cicero, “ who are bound in fetters, before they
are able to form any judgment of what is right or true, and who have been led to yield themselves up, in their tender
years, to the guidance of some friend, or to the captivating eloquence of the teacher whom they have first heard, they as¬
sume to themselves the right of pronouncing upon questions of which they are completely ignorant; adhering to whatever
creed the wind of doctrine may have driven them, as if it were the only rock on which their safety depended.”—Cic.
Lucullus, 3.
DISS. I. PART I. C
18
PRELIMINARY DISSERTATIONS.
strained and guided within certain artificial
channels, marked out hy the narrow views of
human policy. The diffusion of knowledge,
therefore, occasioned hy the rise of the lower
orders, would necessarily contribute to the im¬
provement of useful science, not merely in pro¬
portion to the arithmetical number of cultivated
minds now combined in the pursuit of truth,
but in a proportion tending to accelerate that
important effect with a far greater rapidity.
Nor ought we here to overlook the influence
of the foregoing causes, in encouraging among
authors the practice of addressing the multitude
in their own vernacular tongues. The zeal of
the Reformers first gave birth to this invaluable
innovation, and imposed on their adversaries
the necessity of employing, in their own de¬
fence, the same weapons.1 2 From that moment
the prejudice began to vanish which had so
long confounded knowledge with erudition; and
a revolution commenced in the republic of let¬
ters, analogous to what the invention of gun¬
powder produced in the art of war. “ All the
splendid distinctions of mankind,” as the Cham¬
pion and Flower of Chivalry indignantly ex¬
claimed, <{ were thereby thrown down; and
the naked shepherd levelled with the knight
clad in steel.”
To all these considerations may he added the
gradual effects of time and experience in cor¬
recting the errors and prejudices which had
misled philosophers during so long a succession
of ages. To this cause, chiefly, must he ascrib¬
ed the ardour with which we find various inge¬
nious men, soon after the period in question,
employed in prosecuting experimental inquiries ;
a species of study to which nothing analogous
occurs in the history of ancient science.3 * The
boldest and most successful of this new school
was the celebrated Paracelsus, born in 1493,
and consequently only ten years younger than
Luther. “ It is impossible to doubt,” says Le
Clerc, in his History of Physic, “ that he pos¬
sessed an extensive knowledge of what is called
the Materia Medica, and that he had employed
much time in working on the animal, the vege¬
table, and the mineral substances of which it is
composed. He seems, besides, to have tried an
immense number of experiments in chemistry;
hut he has this great defect, that he studiously
conceals or disguises the results of his long ex¬
perience.” The same author quotes from Pa¬
racelsus a remarkable expression, in which he
calls the philosophy of Aristotle a wooden foun¬
dation. “ He ought to have attempted,” con¬
tinues Le Clerc, “ to have laid a better ; hut if
he has not done it, he has at least, hy discover¬
ing its weakness, invited his successors to look
out for a firmer basis.”5
Lord Bacon himself, while he censures the
moral frailties of Paracelsus, and the blind em¬
piricism of his followers, indirectly acknowledges
the extent of his experimental information:
“ The ancient sophists may he said to have hid,
hut Paracelsus extinguished the light of nature.
The sophists were only deserters of experience,
hut Paracelsus has betrayed it. At the same
time, he is so far from understanding the right
method of conducting experiments, or of record¬
ing their results, that he has added to the trouble
and tediousness of experimenting. By wander¬
ing through the wilds of experience, his disciples
sometimes stumble upon useful discoveries, not
hy reason, but by accident;—whence rashly
proceeding to form theories, they carry the
smoke and tarnish of their art along with them;
and, like childish operators at the furnace, at¬
tempt to raise a structure of philosophy with a
few experiments of distillation.”
Two other circumstances, of a nature widely
different from those hitherto enumerated, al¬
though, probably, in no small degree to be ac¬
counted for on the same principles, seconded,
with an incalculable accession of power, the sud-
1 “ The sacred books were, in almost all the kingdoms and states of Europe, translated into the language of each respec¬
tive people, particularly in Germany, Italy, France, and Britain.”—(Mosheim’s Eccles. IJist. Voh III. p. 205.) The effect
of this single circumstance in multiplying the number of readers and of thinkers, and in giving a certain stability to the
mutable forms of oral speech, may be easily imagined. The common translation of the Bible into English is pronounced by
Dr Lowth to be still the best standard of our language. . „
2 “ Hmc nostra (ut ssepe diximus) felicitatis cujusdam sunt potius quam facultatis, et potius temporis partus qua?n ingenn. —
Nov. Org. Lib. i. c. xxiii.
* Histoire de la Medecine (a la Haye, 1729), p. 819.
DISSERTATION FIRST.
19
den impulse which the human mind had just re¬
ceived. The same century which the invention
of printing and the revival of letters have made
for ever memorable, was also illustrated by the dis¬
covery of the New World, and of the passage to
India by the Cape of Good Hope;—events which
may be justly regarded as fixing a new era in
the political and moral history of mankind, and
which still continue to exert a growing influence
over the general condition of our species. “ It
is an era,” as Raynal observes, “ which gave
rise to a revolution, not only in the commerce
of nations, but in the manners, industry, and
government of the world. At this period new
connections were formed by the inhabitants of
the most distant regions, for the supply of wants
which they had never before experienced. The
productions of climates situated under the equa¬
tor, were consumed in countries bordering on
the pole; the industry of the north was trans¬
planted to the south; and the inhabitants of the
west were clothed with the manufactures of the
east; a general intercourse of opinions, laws and
customs, diseases and remedies, virtues and vices,
was established among men.”
<£ Every thing,” continues the same writer,
“ has changed, and must yet change more. But
it is a question, whether the revolutions that are
past, or those which must hereafter take place,
have been, or can he, of any utility to the hu¬
man race. Will they add to the tranquillity, to
the enjoyments, and to the happiness of man¬
kind ? Can they improve our present state, or
do they only change it ?”
I have introduced this quotation, not with the
design of attempting at present any reply to the
very interesting question with which it con¬
cludes, hut merely to convey some slight notion
of the political and moral importance of the
events in question. I cannot, however, forbear
to remark, in addition to Raynal’s eloquent and
impressive summary, the inestimable treasure of
new facts which these events have furnished for
illustrating the versatile nature of man, and the
history of civil society. In this respect (as Ba¬
con has well observed) they have fully verified
the Scripture prophecy, multi pertransibunt et au-
gebitur scientia ; or, in the still more emphatical
words of our English version, “ Many shall go
to and fro, and knowledge shall be increased.”1
The same prediction may be applied to the gra¬
dual renewal, (in proportion as modern govern¬
ments became effectual in securing order and
tranquillity) of that intercourse between the dif¬
ferent states of Europe, which had, in a great
measure, ceased during the anarchy and turbu¬
lence of the middle ages.
In consequence of these combined causes, aid¬
ed by some others of secondary importance,2 the
Genius of the human race seems, all at once,
to have awakened with renovated and giant
strength, from his long sleep. In less than a
1 “ Neque omittenda est pi'ophetia Danielis de ultimis mundi temporibus; multi pertraruilnint et augebitur scientia: Ma-
nifeste innuens et significans, esse in fatis, id est, in providentia, ut pertransitus mundi (qui per tot longinquas navigationes
impletur plane, aut jam in opere esse videtur) et augmenta scientiarum in eandem setatem incidant.”—Nov. Org. Lib. xciii.
2 Such as the accidental inventions of the telescope and of the microscope. The powerful influence of these inventions may
be easily conceived, not only in advancing the sciences of Astronomy and of Natural History, but in banishing many of
the scholastic prejudices then universally prevalent. The effects of the telescope, in this respect, have been often re¬
marked ; but less attention has been given to those of the microscope, which, however, it is probable, contributed not a
little to prepare the way for the modem revival of the Atomic or Corpuscular Philosophy, by Bacon, Gassendi, and New¬
ton. That, on the mind of Bacon, the wonders disclosed by the microscope produced a strong impression in favour of the
Epicurean physics, may be inferred from his own words. “ Perspicillum (microscopicum) si vidisset Democritus, exsilu-
isset forte; et modum videndi Atomum, quem ille invisibilem omnino affirmavit, inventum fuisse putasset.”—Nov. Org.
Lib. ii. § 39.
We are told in the life of Galileo, that when the telescope was invented, some individuals carried to so great a length
their devotion to Aristotle, that they positively refused to look through that instrument: so averse were they to open
their eyes to any truths inconsistent with their favourite creed—{Vita di Galileo, Yenezia, 1744). It is amusing to find
some other followers of the Stagirite, a very few years afterwards, when they found it impossible any longer to call in
question the evidence of sense, asserting that it was from a passage in Aristotle, where he attempts to explain why stars
become visible in the day-time when viewed from the bottom of a deep well, that the invention of the telescope was bor¬
rowed. The two facts, when combined, exhibit a truly characteristical portrait of one of the most fatal weaknesses
incident to humanity; and form a moral apologue, daily exemplified on subjects of still nearer and higher interest than
the phenomena of the heavens.
In ascribing to accident the inventions of the telescope and of the microscope, I have expressed myself in conformity to
common language; but it ought not to be overlooked, that an invention may be accidental with respect to the particular
author, and yet may be the natural result of the circumstances of society at the period when it took place. As to the in¬
struments in question, the combination of lenses employed in their structure is so simple, that it could scarcely escape the
notice of all the experimenters and mechanicians of that busy and inquisitive age. A similar remark has been made by
20
PRELIMINARY DISSERTATIONS.
century from the invention of printing, and the
fall of the Eastern empire, Copernicus discovered
the true theory of the planetary motions, and a
very few years afterwards, was succeeded by the
three great precursors of Newton,—Tycho Brahe,
Kepler, and Galileo.
The step made by Copernicus may he justly
regarded as one of the proudest triumphs of hu¬
man reason;—whether we consider the sagacity
which enabled the author to obviate, to his own
satisfaction, the many plausible objections which
must have presented themselves against his con¬
clusions, at a period when the theory of motion
was so imperfectly understood; or the hold spi¬
rit of inquiry which encouraged him to exercise
his private judgment, in opposition to the autho¬
rity of Aristotle,—to the decrees of the church
of Rome,—and to the universal belief of the
learned, during a long succession of ages. He
appears, indeed, to have well merited the enco¬
mium bestowed on him by Kepler, who calls
him “ a man of vast genius, and, what is of still
greater moment in these researches, a man of a
free mind.”
The establishment of the Copernican system,
beside the new field of study which it opened to
Astronomers, must have had great effects on
philosophy in all its branches, by inspiring those
sanguine prospects of future improvement, which
stimulate curiosity, and invigorate the inventive
powers. It afforded to the common sense, even
of the illiterate, a palpable and incontrovertible
proof, that the ancients had not exhausted the
stock of possible discoveries; and that, in mat¬
ters of science, the creed of the Romish church
was not infallible. In the conclusion of one of
Kepler’s works, we perceive the influence of
these prospects on his mind. “ Haec et cetera
hujusmodi latent in pandectis sevi sequentis, non
antea discenda, quam librum hunc Deus arbiter
saeculorum recluserit mortalihus.”1
I have hitherto taken no notice of the effects
of the revival of letters on Metaphysical, Moral,
or Political science. The truth is, that little de¬
serving of our attention occurs in any of these
departments prior to the seventeenth century;
and nothing which hears the most remote ana¬
logy to the rapid strides made, during the six¬
teenth, in mathematics, astronomy, and physics.
The influence, indeed, of the Reformation on
the practical doctrines of ethics appears to have
been great and immediate. We may judge of
this from a passage in Melanchthon, where he
combats the pernicious and impious tenets of
those theologians who maintained, that moral
distinctions are created entirely by the arbitrary
and revealed will of God. In opposition to this
heresy, he expresses himself in these memorable
words :—“ Wherefore our decision is this; that
those precepts which learned men have commit¬
ted to writing, transcribing them from the com¬
mon reason and common feelings of human na¬
ture, are to be accounted as not less divine, than
those contained in the tables given to Moses;
and that it could not be the intention of our
Maker to supersede, by a law graven upon stone,
that which is written with his own finger on the
table of the heart.”2—This language was, un¬
doubtedly, a most important step towards a just
system of Moral Philosophy; hut still, like the
other steps of the Reformers, it was only a return
to common sense, and to the genuine spirit of
Christianity, from the dogmas imposed on the
credulity of mankind by an ambitious priest¬
hood.5 Many years were yet to elapse, before
Condorcet concerning the invention of printing. “ L’invention de 1’Imprimerie a sans doute avance le progres de 1 espece
humaine ; mais cette invention dtoit elle-meme une suite de I’usagede la lecture repandu dans un grand nombre <*e pays.
Vie de Turgot.
1 Epit. Astron. Copernic. < . . , . ,
2 Proinde sic statuimus, nihilo minus divina praecepta esse ea, quae a sensu communi et naturae judicio mutuati docti ho¬
mines gentiles literis mandarunt, quam quae extant in ipsis saxeis Mosis tabulis. Neque ille ipse caelestis 1 ater pluns a
nobis fieri eas leges voluit, quas in saxo scripsit, quam quas in ipsos animorum nostrorum sensus impresserat.
Not having it in my power at present to consult Melanchthon’s works, I have transcribed the foregoing paragraph on the
authority of a learned German Professor, Christ. Meiners—See his Historia Doctrine de Ven Deo. . Lemgoviae, GoO, p. 12.
3 It is observed by Dr Cudworth, that the doctrine which refers the origin of moral distinctions to the arbitrary ap¬
pointment of the Deity, was strongly reprobated by the ancient fathers of the Christian church, and that “ it crept up
afterward in the scholastic ages; Occam being among the first that maintained that there is no act evil, hut as it is prohi¬
bited by God, and which cannot he made good, if it be commanded by him. In this doctrine he was quickly followed by
Petrus Alliacus, Andreas de Novo Castro, and others.”—See Treatise of Immutable Morality.
It is pleasing to remark, how very generally the heresy here ascribed to Occam is now reprobated by good men of ail
DISSERTATION FIRST.
21
any attempts were to be made to trace, with
analytical accuracy, the moral phenomena of
human life to their first principles in the consti¬
tution and condition of man, or even to disen¬
tangle the plain and practical lessons of ethics
from the speculative and controverted articles of
theological systems.1
A similar observation may be applied to the
powerful appeals, in the early Protestant wri¬
ters, to the moral judgment and moral feelings
of the human race, from those casuistical subtle¬
ties, with which the schoolmen and monks of
the middle ages had studied to obscure the light
of nature, and to stifle the voice of conscience.
These subtleties were precisely analogous in
their spirit to the pia et religiosa caUiditas, after¬
wards adopted in the casuistry of the Jesuits,
and so inimitably exposed by Pascal in the Pro¬
vincial Letters. The arguments against them
employed by the Reformers, cannot, in strict pro¬
priety, be considered as positive accession to the
stock of human knowledge; but what scientific
discoveries can be compared to them in value !8
From this period may be dated the decline5
of that worst of all heresies of the Romish
church, which, by opposing Revelation to Rea¬
son, endeavoured to extinguish the light of both ;
and the absurdity, so happily described by
Locke, became every day more manifest, of at¬
tempting “ to persuade men to put out their
eyes, that they might the better receive the re¬
mote light of an invisible star by a telescope.”
persuasions. The Catholics have even begun to recriminate on the Reformers as the first broachers of it; and it is to be
regretted, that in some of the writings of the latter, too near approaches to it are to be found. The truth is, as Burnet
long ago observed, that the effects of the Reformation have not been confined to the reformed churches;—to which it may
be added, that both Catholics and Protestants have, since that era, profited very largely by the general progress of the
sciences and of human reason.
I quote the following sentence from a highly respectable Catholic writer on the law of nature and nations:—“ Q,ui ra-
tionem exsulare jubent a moralibus praeceptis quae in sacris literis traduntur, et in absurdam enormemque Luthe-ri sen-
tentiam imprudentes incidunt (quam egregie et elegantissime refutavit Melchior Canus Loc. Theolog. Lib. ix; et x.), et ea
docent, quae si sectatores inveniant moralia omnia susque deque miscere, ac revelationem ipsam inutilem omnino et ineffi-
cacem redderepossent.”—(Lampredi Feorentini Juris Natures et Gentium Thcoremata, Tom. II. p. 195. Pisis, 1782). For
the continuation of the passage, which would do credit to the most liberal Protestant, I must refer to the original work. The.
zeal of Luther for the doctrine of the Nominalists had probably prepossessed him, in his early years, in favour of some of
the theological tenets of Occam, and afterwards prevented him from testifying his disapprobation of them so explicitly and
decidedly as Melanchthon and other reformers have done.
1 “ The theological system (says the learned and judicious Mosheim) that now prevails in the Lutheran academies, is not
of the same tenor or spirit with that which was adopted in the infancy of the Reformation. The glorious defenders of re¬
ligious liberty, to whom we owe the various blessings of the Reformation, could not, at once, behold the truth in all its
lustre, and in all its extent; but, as usually happens to persons that have been long accustomed to the darkness of igno¬
rance, their approaches towards knowledge were but slow, and their views of things but imperfect.”—(Maclaine’s Transl.
of Mosheim. London, 2d ed. Yol. IV. p. 19-) He afterwards mentions one of Luther’s early disciples (Amsdorff) “ who
was so far transported and infatuated by his excessive zeal for the supposed doctrine of his master, as to maintain, that
good works are an impediment to salvation”—Ibid. p. 39.
Mosheim, after remarking that “ there are more excellent rules of conduct in the few practical productions of Luther
and Melanchthon, than are to be found in the innumerable volumes of all the ancient casuists and moralisers,” candidly ac¬
knowledges, “ that the notions of these great men concerning the important science of morality were far from being suffi¬
ciently accurate or extensive. Melanchthon himself, whose exquisite judgment rendered him peculiarly capable of re¬
ducing into a compendious system the elements of every science, never seems to have thought of treating morals in this
manner ; but has inserted, on the contrary, all his practical rules and instructions, under the theological articles that relate
to the law, sin, free-will, faith, hope, and charity.”—Mosheim’s Eccles. Hist. Vol. IV. pp. 23. 24.
The same author elsewhere observes, that “ the progress of morality among the reformed was obstructed by the very
same means that retarded its improvement among the Lutherans ; and that it was left in a rude and imperfect state by
Calvin and his associates. It was neglected amidst the tumult of controversy ; and, while every pen was drawn to main¬
tain certain systems of doctrine, few were employed in cultivating that master-science which has virtue, life, and manners,
for its objects.”—Ibid. pp. 120. 121. _ _ .
2 “ Et tamen hi doctores angelici, cherubici, seraphici, non modo universam philosophiam ac theologian! erronbus quam-
plurimis inquinarunt: verum etiam in philosophiam moralem invexere sacerrima ista principia probabilismi, methodi dirigendi
intentionem, reservationis mentalis,peccati philosophici, quibus Jesuitse etiamnum mirifice delectantur.”—Heinecc. Elem. Histor.
Phil. § ci. See also the references.
With respect to the ethics of the Jesuits, which exhibit a very fair picture of the general state of that science, prior to
the Reformation, See the Provhicial Letters ; Mosheim’s Ecclesiastical History, Vol. IV. p. 354; Dornford’s Translation of
Putter's Historical Developcment of the present Political Constitution of the Germanic Empire, Vol. II. p. 6.; and the Appendix
to Penrose’s Hampton Lectures.
3 I have said, the decline of this heresy; for it was by no means immediately extirpated even in the reformed churches.
“ As late as the year 1598, Daniel Hofman, Professor of Divinity in the University of Helmstadt, laying hold of some
particular opinions of Luther, extravagantly maintained, that philosophy was the mortal enemy of religion ; that tiuth was
divisible into two branches, the one philosophical and the other theological; and that what was true in philosophy was fa.se in
theology.”—Mosheim, Vol. IV. p. 18.
22
PRELIMINARY DISSERTATIONS.
In the meantime, a powerful obstacle to the
progress of practical morality and of sound policy,
was superadded to those previously existing in
Catholic countries, by the rapid growth and ex¬
tensive influence of the Machiavelian school.
The founder of this new sect, or, to speak more
correctly, the systematizer and apostle of its
doctrines, was born as early as 1469, that is,
about ten years before Luther; and, like that
reformer, acquired, by the commanding superio¬
rity of his genius, an astonishing ascendant,
though of a very different nature, over the
minds of his followers. No writer, certainly,
either in ancient or in modern times, has ever
united, in a more remarkable degree, a greater
variety of the most dissimilar and seemingly
the most discordant gifts and attainments;—a
profound acquaintance with all those arts of dis¬
simulation and intrigue, which in the petty
cabinets of Italy, were then universally con¬
founded with political wisdom; an imagination
familiarized to the cool contemplation of what¬
ever is perfidious or atrocious in the history of
conspirators and of tyrants; combined with a
graphical skill in holding up to laughter the
comparatively harmless follies of ordinary life.
His dramatic humour has been often compared
to that of Moliere; but it resembles it rather in
comic force, than in benevolent gaiety or in
chastened morality. Such as it is, however, it
forms an extraordinary contrast to that strength
of intellectual character, which, in one page,
reminds us of the deep sense of Tacitus, and in
the next, of the dark and infernal policy of
Caesar Borgia. To all this must be supperadded
a purity of taste, which has enabled him, as an
historian, to rival the severe simplicity of the
Grecian masters; and a sagacity in combining
historical facts, which was afterwards to afford
lights to the school of Montesquieu.
Eminent, however, as the talents of Ma-
chiavel unquestionably were, he cannot be num¬
bered among the benefactors of mankind. In
none of his writings does he exhibit any marks
of that lively sympathy with the fortunes of the
human race, or of that warm zeal for the inte¬
rests of truth and justice, without the guidance
of which, the highest mental endowments, when
applied to moral or to political researches, are
in perpetual danger of mistaking their way.
What is still more remarkable, he seems to have
been altogether blind to the mighty changes in
human affairs, which, in consequence of the re¬
cent invention of printing, were about to result
from the progress of Reason and the diffusion
of Knowledge. Through the whole of his Prmce
(the most noted as well as one of the latest of
his publications) he proceeds on the supposition,
that the sovereign has no other object in go¬
verning, but his own advantage; the very cir¬
cumstance which, in the judgment of Aristotle,
constitutes the essence of the worst species of
tyranny.1 He assumes also the possibility of
retaining mankind in perpetual bondage by the
old policy of the double doctrine; or, in other
words, by enlightening the few, and hoodwink¬
ing the many;—a policy less or more practised
by statesmen in all ages and countries; but
which, wherever the freedom of the press is re¬
spected, cannot fail, by the insult it offers to
the discernment of the multitude, to increase
the insecurity of those who have the weakness
to employ it. It has been contended, indeed,
by some of Machiavel’s apologists, that his real
object in unfolding and systematising the mys¬
teries of King-Craft, was to point out indirectly
to the governed the means by which the en¬
croachments of their rulers might be most ef¬
fectually resisted; and, at the same time, to
satirize, under the ironical mask of loyal and
courtly admonition, the characteristical vices of
princes.2 But, although this hypothesis has
been sanctioned by several distinguished names,
and derives some verisimilitude from various in¬
cidents in the author’s life, it will be found, on
examination, quite untenable; and accordingly
it is now, I believe, very generally rejected.
One thing is certain, that if such were actually
1 “ There is a third kind of tyranny, which most properly deserves that odious name, and which stands in direct opposi¬
tion to royalty; it takes place when one man, the worst perhaps and basest in the country, governs a kingdom with no
other view than the advantage of himself and his family.”—Atustotle’s Politics, Book vi. chap. x. See Dr Gillies’#
Translation.
* See Note C.
DISSERTATION FIRST.
23
MacliiavePs views, they were much too refined
for the capacity of his royal pupils. By many
of these his hook has been adopted as a manual
for daily use; hut I have never heard of a single
instance, in which it has been regarded by this
class of students as a disguised panegyric upon
liberty and virtue. The question concerning the
motives of the author is surely of little moment,
when experience has enabled us to pronounce so
decidedly on the practical effects of his precepts.
“ About the period of the Reformation,” says
Condorcet, “ the principles of religious Machia-
velism had become the only creed of princes, of
ministers, and of pontiffs ; and the same opinions
had contributed to corrupt philosophy. What
code, indeed, of morals,” he adds, “ was to he
expected from a system, of which one of the
principles is,—that it is necessary to support the
morality of the people by false pretences, and
that men of enlightened minds have a right to
retain others in the chains from which they have
themselves contrived to escape !” The fact is
perhaps stated in terms somewhat too unquali¬
fied ; but there are the best reasons for believing
that the exceptions were few, when compared
with the general proposition.
The consequences of the prevalence of such a
creed among the rulers of mankind were such
as might he expected. “ Infamous crimes, as¬
sassinations, and poisonings (says a French his¬
torian), prevailed more than ever. They were
thought to he the growth of Italy, where the
rage and weakness of the opposite factions con¬
spired to multiply them. Morality gradually
disappeared, and with it all security in the inter¬
course of life. The first principles of duty
were obliterated by the joint influence of atheism
and of superstition.”1
And here, may I he permitted to caution my
readers against the common error of confound¬
ing the double doctrine of Machiavelian politi¬
cians, with the benevolent reverence for establish¬
ed opinions, manifested in the noted maxim of
Fontenelle,—“ that a wise man, even when his
hand was full of truths, would often content
himself with opening his little finger.” Of the
advocates for the former, it may he justly said,
that “ they love darkness rather than light,
because their deeds are evil;” well knowing, if I
may borrow the words of Bacon, “ that the
open day-light doth not show the masks and
mummeries, and triumphs of the world, half so
stately as candle-light.” The philosopher, on
the other hand, who is duly impressed with the
latter, may be compared to the oculist, who,
after removing the cataract of his patient, pre¬
pares the still irritable eye, by the glimmering
dawn of a darkened apartment, for enjoying in
safety the light of day.®
Machiavel is well known to have been, at
bottom, no friend to the priesthood; and his
character has been stigmatized by many of the
order with the most opprobrious epithets. It is
nevertheless certain, that to his maxims the
royal defenders of the Catholic faith have been
indebted for the spirit of that policy which they
have uniformly opposed to the innovations of the
Reformers. The Prince was a favourite book of
the Emperor Charles V.; and was called the
Bible of Catharine of Medicis. At the court of
the latter, while Regent of France, those who
approached her are said to have professed open-
1 Millot.
1 How strange is the following misrepresentation of Fontenelle’s fine and deep saying, by the comparatively coarse hand
of the Baron de Grimm ! “ II disoit, que s’il eut tenu la verite dans ses mains comme un oiseau, il 1’auroit etouffee, tant il
regardoit le plus beau present du ciel inutile et dangereux pour le genre humain.”—(Memoires Historiqnes, &c. par le
Baron de Grimm. Londres, 1814. Tome I. p. 340.) Of the complete inconsistency of this statement, not only with the
testimony of his most authentic biographers, hut with the general tenor both of his life and writings, a judgment may be
formed from an expression of B’Alembert, in his very ingenious and philosophical parallel between Fontenelle and La
Motte. “ Tous deux ont porte trop loin leur revolte ddcidee, quoique douce en apparence, contre les dieux et les lois du
Pamasse ; mais la libertd des opinions de la Motte semble tenir plus intimement a 1’interet personnel qu’il avoit de les
soutenir; et la liberte des opinions de Fontenelle a V inter et general, peut-ltre quelquefois mal entendu, qu'il prenoit au progres
de la raison dans tous les genres. What follows may be regarded in the light of a comment on the maxim above quoted :
“ La finesse de la Motte est plus developpee, celle de Fontenelle laisse plus a deviner a son lecteur. La Motte, sans
jamais en trop dire, n’oublie de ce que son sujet lui presente, met habilement tout en oeuvre, et semble craindre perdre
par des reticences trop subtiles quelqu’un de ses avantages ; Fontenelle, sans jamais etre obscur, excepte pour ceux qui
ne meritent pas meme qu’on soit clair, se manage a la fois et le plaisir de sous-entendre, et celui d’esperer qu’il sera pleine-
ment entendu par ceux qui en sont dignes.”—Eloge de la Motte.
24
PRELIMINARY DISSERTATIONS.
ly its most atrocious maxims ; particularly that
which recommends to sovereigns not to commit
crimes by halves. The Italian cardinals, who
are supposed to have been the secret instigators
of the massacre of St Bartholomew, were bred
in the same school.1
It is observed by Mr Hume, that <£ there is
scarcely any maxim in the Prince, which subse¬
quent experience has not entirely refuted.”
“ Machiavel,” says the same writer, 44 was cer¬
tainly a great genius ; but having confined his
study to the furious and tyrannical governments
of ancient times, or to the little disorderly prin¬
cipalities of Italy, his reasonings, especially upon
monarchical governments, have been found ex¬
tremely defective. The errors of this politician
proceeded, in a great measure, from his having
lived in too early an age of the world, to be a
good judge of political truth.”4
To these very judicious remarks, it may he
added, that the bent of Machiavel’s mind seems
to have disposed him much more strongly to
combine and to generalize his historical reading,
than to remount to the first principles of politi¬
cal science, in the constitution of human nature,
and in the immutable truths of morality. His
conclusions, accordingly, ingenious and refined
as they commonly are, amount to little more
(with a few very splendid exceptions) than em¬
pirical results from the events of past ages. To
the student of ancient history they may he often
both interesting and instructive; but, to the
modern politician, the most important lesson
they afford is, the danger, in the present circum¬
stances of the world, of trusting to such re¬
sults, as maxims of universal application, or of
permanent utility.
The progress of political philosophy, and along
with it of morality and good order, in every
part of Europe, since the period of which I am
now speaking, forms so pleasing a comment on
the profligate and short-sighted policy of Ma¬
chiavel, that I cannot help pausing for a mo¬
ment to remark the fact. In stating it, I shall
avail myself of the words of the same profound
writer, whose strictures on Machiavel’s Prince I
had already occasion to quote. 44 Though ad
kinds of government,” says Mr Hume, 44 he im¬
proved in modern times, yet monarchical govern¬
ment seems to have made the greatest advances
towards perfection. It may now he affirmed of
civilized monarchies, what was formerly said of
republics alone, that they are a government of
laws, not of men. They are found susceptible
of order, method, and constancy, to a surprising
degree. Property is there secure, industry en¬
couraged, the arts flourish, and the prince lives
secure among his subjects, like a father among
his children. There are, perhaps, and have been
for two centuries, near two hundred absolute
princes, great and small, in Europe; and allow¬
ing twenty years to each reign, we may suppose
that there have been in the whole two thousand
monarchs, or tyrants, as the Greeks would have
called them. Yet of these there has not been
one, not even Philip II. of Spain, so had as
Tiberius, Caligula, Nero, or Domitian, who were
four in twelve among the Roman Emperors.”5
For this very remarkable fact, it seems diffi¬
cult to assign any cause equal to the effect, but
the increased diffusion of knowledge (imperfect,
alas ! as this diffusion still is) by means of the
Press; which, while it has raised, in free states, a
growing bulwark against the oppression of rulers,
in the light and spirit of the people, has, even
under the most absolute governments, had a
powerful influence—by teaching princes to re¬
gard the wealth and prosperity and instruction of
their subjects as the firmest basis of their gran¬
deur—in directing their attention to objects of
national and permanent utility. How encoura¬
ging the prospect thus opened of the future his¬
tory of the world ! And what a motive to ani¬
mate the ambition of those, who, in the solitude
of the closet, aspire to bequeath their contribu¬
tions, how slender soever, to the progressive
mass of human improvement and happiness !
In the bright constellation of scholars, histo¬
rians, artists, and wits, who shed so strong a
lustre on Italy during that splendid period of its
history which commences with the revival of
1 Voltaire, Essay on Universal History.
2 Essay on Civil Liberty.
2 Ibid.
DISSERTATION FIRST.
25
letters, it is surprising how few names occur,
which it is possible to connect, by any palpable
link, with the philosophical or political specula¬
tions of the present times. As an original and
profound thinker, the genius of Machiavel com¬
pletely eclipses that of all his contemporaries.
Not that Italy was then destitute of writers who
pretended to the character of philosophers; hut
as their attempts were, in general, limited to the
exclusive illustration and defence of some one
or other of the ancient systems for which they
had conceived a predilection, they added but
little of their own to the stock of useful know¬
ledge, and are now remembered chiefly from
the occasional recurrence of their names in the
catalogues of the curious, or in the works of
philological erudition. The zeal of Cardinal
Bessarion, and of Marsilius Ficinus, for the re¬
vival of the Platonic philosophy, was more pe¬
culiarly remarkable, and, at one time, produced
so general an impression, as to alarm the follow¬
ers of Aristotle for the tottering authority of
their master. If we may credit Launoius, this
great revolution was on the point of being ac¬
tually accomplished, when Cardinal Bellarmine
warned Pope Clement VIII. of the peculiar dan¬
ger of showing any favour to a philosopher
whose opinions approached so nearly as those
of Plato to the truths revealed in the Gospel.
In what manner Bellarmine connected his con¬
clusions with his premises, we are not informed.
To those who are uninitiated in the mysteries of
the conclave, his inference would certainly ap¬
pear much less logical than that of the old Ro¬
man Pagans, who petitioned the Senate to con¬
demn the works of Cicero to the flames, as they
predisposed the minds of those who read them
for embracing the Christian faith.
By a small band of bolder innovators belong¬
ing to this golden age of Italian literature, the
Aristotelian doctrines were more directly and
powerfully assailed. Laurentius Valla, Marius
Nizolius, and Franciscus Patricius,1 2 have all of
them transmitted their names to posterity as
philosophical reformers, and, in particular, as
revolters against the authority of the Stagirite.
Of the individuals just mentioned, Nizolius is the
only one who seems entitled to maintain a per¬
manent place in the annals of modern science.
His principal work, entitled Antibarbarus^ is
not only a bold invective against the prevailing
ignorance and barbarism of the schools, but con¬
tains so able an argument against the then fashion¬
able doctrine of the Realists concerning general
ideas, that Leibnitz thought it worth while, a centu¬
ry afterwards, to republish it, with the addition of
a long and valuable preface written by himself.
At the same period with Franciscus Patricius,
flourished another learned Italian, Albericus
Gentilis, whose writings seem to have attracted
more notice in England and Germany than in
his own country. His attachment to the reform¬
ed faith having driven him from Italy, he sought
an asylum at Oxford, where, in 1587, he was ap¬
pointed professor of the Civil Law, an office
which he held till the period of his death in
1611.3 He was the author of a treatise De Jure
Belli, in three books, which appeared successively
in 1588 and 1589, and were first published to¬
gether at Hanau in 1598. His name, however,
has already sunk into almost total oblivion; and
I should certainly not have mentioned it on the
present occasion? were it not for his indisputable
merits as the precursor of Grotius, in a depart¬
ment of study which, forty years afterwards,
the celebrated treatise De Jure Belli et Pads was
1 His Discussion.es Peripateticoe were printed at Venice in 1571. Another work, entitled Novade Universis Philosophia, also
printed at Venice, appeared in 1593. I have never happened to meet with either; but from the account given of the au-
thor by Thuanus, he does not seem to have attracted that notice from his contemporaries, to which his learning and talents
entitled him (Thuan. Hist. Lib. cxix. xvii.). His Discussiones Peripateticce are mentioned by Brucker in the following
terms: “ Opus egregium, doctum, varium, luculentum, sed invidia odioque iti Aristotelem plenum satis superquc."—(Hist.
Phil. Tom. IV. p. 425). The same very laborious and candid writer acknowledges the assistance he had derived from Pa-
tricius in his account of the Peripatetic philosophy—“ In qua tractatione fatemur egregiam enitere Patricii dpctrinam, m-
genii elegantiam prorsus admirabilem, et quod primo loco ponendum est, insolitam veteris philosophise cognitionem, cujus
ope nos Peripatetics; discipline historie multoties lucem attulisse, grati suis locis professi sumus.”—Ibid. p. 426.^
2 Antibarbarus, sive de Verts Principiis et Vera Ratione Philosophandi contra Pseudo-philosophos. Parmae, 1553. “ Les taux
philosophes,” dit Fontenelle, “ dtoient tous les scholastiques passes et pre'sens; et Nizolius s’eleve avec la derniere hardi-
esse contre leurs ide'es monstrueuses et leur langage barbare. La longue et constante admiration qu’on avoit eu pour Ans-
tote, ne prouvoit, disoit-il, que la multitude des sots et la duree de la sottise.” The merits of this writer are much too
lightly estimated by Brucker—See Hist. Phil. Tom. IV. Pars I. pp. 91. 92.
3 Wood’s Athence Oxonienses, Vol. II. col. 90. Dr Bliss’s edition.
DISS. I. PART I. D
26
PRELIMINARY DISSERTATIONS.
to raise to so conspicuous a rank among the
branches of academical education. The avowed
aim of this new science, when combined with
the anxiety of Gentilis to counteract the effect
of Machiavel’s Prince, by representing it as a
warning to subjects rather than as a manual of
instruction for their rulers, may he regarded as
satisfactory evidence of the growing influence,
even at that era, of better ethical principles than
those commonly imputed to the Florentine Secre¬
tary. 1
The only other Italian of whom I shall take
notice at present, is Campanella;2 * a philoso¬
pher now remembered chiefly in consequence of
his eccentric character and eventful life, but of
whom Leibnitz has spoken in terms of such
high admiration, as to place him in the same
line with Bacon. After looking into several of
his works with some attention, I must confess
I am at a loss to conceive upon what grounds
the eulogy of Leibnitz proceeds; but as it is
difficult to suppose, that the praise of this great
man was, in any instance, the result of mere
caprice, I shall put it in the power of my read¬
ers to judge for themselves, by subjoining a
faithful translation of his words. I do this the
more willingly, as the passage itself (whatever
may be thought of the critical judgments pro¬
nounced in it), contains some general remarks
on intellectual character, which are in every re¬
spect worthy of the author.
“ Some men, in conducting operations where
an attention to minutiae is requisite, discover a
mind vigorous, subtile, and versatile, and seem
to be equal to any undertaking, how arduous
soever. But when they are called upon to act
on a greater scale, they hesitate and are lost in
their own meditations ; distrustful of their judg¬
ment, and conscious of their incompetency to
the scene in which they are placed: men, in a
word, possessed of a genius rather acute than
comprehensive. A similar difference may be
traced among authors. What can be more
acute than Descartes in Physics, or than Hohhes
in Morals ! And yet, if the one be compa¬
red with Bacon, and the other with Campa¬
nella, the former writers seem to grovel upon
the earth,—the latter to soar to the Heavens, by
the vastness of their conceptions, their plans,
and their enterprises, and to aim at objects be¬
yond the reach of the human powers. The
former, accordingly, are best fitted for deliver¬
ing the first elements of knowledge, the latter
for establishing conclusions of important and
general application.”5
The annals of France, during this period,
present very scanty materials for the History
of Philosophy. The name of the Chancellor
de 1’Hopital, however, must not be passed over
in silence. As an author, he does not rank
high; nor does he seem to have at all valued
himself on the careless effusions of his literary
hours; but, as an upright and virtuous magis¬
trate, he has left behind him a reputation un¬
rivalled to this day.4 His wise and indulgent
principles on the subject of religious liberty,
and the steadiness with which he adhered to
them, under circumstances of extraordinary dif¬
ficulty and danger, exhibit a splendid contrast
to the cruel intolerance, which, a few years be-
1 The claims of Albericus Gentilis to be regarded as the father of Natural Jurisprudence, are strongly asserted by his
countryman Lampredi, in his very judicious and elegant work, entitled, Juris Publici Theoremata, published at Pisa in
1782. “ Hie primus jus'aliquod Belli et esse et tradi posse excogitavit, et Belli et Pads regulas explanavit primus, et
fortasse in causa fuit cur Grotius opus suum conscribere aggrederetur: dignus sane qui prae ceteris memoretur, Italiae
enim, in qua ortus erat, et unde Juris Romani disciplinam hauserat, gloriam auxit, effecitque ut quae fuerat bonarum arti-
um omnium restitutrix et altrix, eadem esset et prima Jurisprudentiae Naturalis magistra.”
2 Born 1568, died 1639.
s Leibnit. Opera, Yol. VI. p. 303, ed. Dutens—It is probable that, in the above passage, Leibnitz alluded more to the
elevated tone of Campanella’s reasoning on moral and political subjects, when contrasted with that of Hobbes, than to the
intellectual superiority of the former writer above the latter. No philosopher, certainly, has spoken with more reverence
than Campanella has done, on various occasions, of the dignity of human nature. A remarkable instance of this occurs in
his eloquent comparison of the human hand with the organs of touch in other animals. (Vide Campan. Physiohg. cap. xx.
Art. 2.) Of his Political Aphorisms, which form the third part of his treatise on Morals, a sufficient idea for our purpose
is conveyed by the concluding corollary, “ Probitas custodit regem populosque; non autem indocta Machiavellistarum astu-
tia.” On the other hand, Campanella’s works abound with immoralities and extravagancies far exceeding those of
Hobbes. In his idea of a pei'fect commonwealth (to which he gives the name of Civitas Solis), the impurity of his imagi¬
nation, and the unsoundness of his judgment, are equally conspicuous. He recommends, under certain regulations, a com¬
munity of women ; and, in every thing connected with procreation, lays great stress on the opinions of astrologers.
4 Magistral au-dessus de tout eloge; et d’apres lequel on a jugd tous ceux qui ont ose s’asseoir sur ce meme tribunal
sans avoir son courage ni ses lumieres.”—Henault, Abrege, Chronologique.
DISSERTATION FIRST.
27
fore, had disgraced the character of an illustri¬
ous Chancellor of England. The same philo¬
sophical and truly catholic spirit distinguished
his friend, the President de Thou,1 2 and gives
the principal charm to the justly admired pre¬
face prefixed to his history. In tracing the pro¬
gress of the human mind during the sixteenth
century, such insulated and anomalous examples
of the triumph of reason over superstition and
bigotry, deserve attention, not less than what
is due, in a history of the experimental arts, to
Friar Bacon’s early anticipation of gunpowder,
and of the telescope.
Contemporary with these great men was Bo-
din (or Bodinus),8 an eminent French lawyer,
who appears to have been one of the first that
united a philosophical turn of thinking with an
extensive knowledge of jurisprudence and of
history. His learning is often ill digested, and
his conclusions still oftener rash and unsound;
yet it is hut justice to him to acknowledge, that,
in his views of the philosophy of law, he has
approached very nearly to some leading ideas
of Lord Bacon;3 while, in his refined combina¬
tions of historical facts, he has more than once
struck into a train of speculation, hearing a
strong resemblance to that afterwards pursued
by Montesquieu.4 Of this resemblance, so re¬
markable an instance occurs in his chapter on
the moral effects of Climate, and on the atten¬
tion due to this circumstance by the legislator,
that it has repeatedly subjected the author of
The Spirit of Laws (but in my opinion without
any good reason) to the imputation of plagia¬
rism.5 A resemblance to Montesquieu, still
more honourable to Bodinus, may be traced in
their common attachment to religious as well as
to civil liberty. To have caught, in the six¬
teenth century, somewhat of the philosophical
spirit of the eighteenth, reflects less credit on
the force of his mind, than to have imbibed, in
the midst of the theological controversies of his
age, those lessons of mutual forbearance and
charity, which a long and sad experience of the
fatal effects of persecution has to this day so im¬
perfectly taught to the most enlightened nations
of Europe.
As a specimen of the liberal and moderate
views of this philosophical politician, I shall
quote two short passages from his Treatise De
la Republique, which seem to me objects of con¬
siderable curiosity, when contrasted with the
general spirit of the age in which they were
written. The first relates to liberty of con¬
science, for which he was a strenuous and in¬
trepid advocate, not only in his publications, but
as a member of the Etals Generaux, assembled
at Blois in 1576. <£ The mightier that a man
is (says Bodin), the more justly and temperate¬
ly he ought to behave himself towards all men,
but especially towards his subjects. Wherefore
the senate and people of Basil did wisely, who,
having renounced the Bishop of Rome’s religion,
would not, upon the sudden, thrust the monks
and nuns, with the other religious persons, out
of their abbeys and monasteries, but only took
order, that, as they died they should die both for
themselves and their successors, expressly for¬
bidding any new to be chosen in their places, so
that, by that means, their colleges might, by
1 “ One cannot help admiring,” says Dr Jortin, “ the decent manner in which the illustrious Thuanus hath spoken ot
Calvin “ Acri vir ac vehementi ingenio, et admirabili facundia prseditus; turn inter protestantes magni nominis theolo-
gus.”—(Life of Erasmus, p. 555.) The same writer has remarked the great decency and moderation with which Thuanus
speaks of Luther—lUd. p. 113.
2 Born 1530, died 1596.
3 See, in particular, the preface to his book, entitled Methodus adfacilem Historiarum cognitionem.
* See the work De la Reyublique, passim. In this treatise there are two chapters singularly curious, considering the time
when they were written ; the second and third chapters of the sixth book. The first is entitled, Des Finances ; the second,
Le Moyen d'emptchcr que les Monnoyes soyent altere.es de Prix ou falsifies. The reasonings of the Author on various points
there treated of, will be apt to excite a smile among those w'ho have studied the Inquiry into the Wealth of Nations ; but it
reflects no small credit on a lawyer of the sixteenth century to have subjected such questions to philosophical examination,
and to have formed so just a conception as Bodin appears evidently to have done, not only of the object, but of the im¬
portance of the modern science of political economy.
Thuanus speaks highly of Bodin’s dissertations ~De Re Monetaria, which I have never seen. The same historian thus ex¬
presses himself with respect to the work De Republica: “ Opus in quo ut omni scientiarum genere non tincti sed imbuti in¬
genii fidem fecit, sic nonnullis, qui recte judicant, non omnino ab ostentationis innato genii vitio vacuum se probavit.—Hist.
Lib. cxvii. ix.
5 See Note D.
28
PRELIMINARY DISSERTATIONS.
little and little, by tbe death of the fellows, he
extinguished. Whereby it came to pass, that all
the rest of the Carthusians, of their own accord,
forsaking their cloisters, yet one of them all
alone for a long time remained therein, quietly
and without any disturbance, holding the right
of his convent, being never enforced to change
either his place, or habit, or old ceremonies, or
religion before by him received. The like older
was taken at Coire in the diet of the Giisons;
wherein it was decreed, that the ministers of
the reformed religion should he maintained of
the profits and revenues of the church, the reli¬
gious men nevertheless still remaining in their
cloisters and convents, to he by their death sup¬
pressed, they being now prohibited to choose any
new instead of them which died. By which
means, they which professed the new religion,
and they who professed the old, were both pro¬
vided for.”1 2 * *
The aim of the chapter from which I have
extracted the foregoing passage, is to show, that
“ it is a most dangerous thing, at one and the
same time, to change the form, laws, and cus¬
toms of a commonwealth.” The scope of the
author’s reasonings may be judged of from the
concluding paragraph.
“ We ought then in the government of a
well-ordered state and commonwealth, to imitate
and follow the great God of Nature, who in all
things proceedeth easily, and by little and little;
who of a little seed causeth to grow a tree for
height and greatness, right admirable, and yet
for all that insensibly; and still by means con¬
joining the extremities of nature, as by putting
the spring between winter and summer, and
autumn betwixt summer and winter, mode¬
rating the extremities of the terms and seasons,
with the self-same wisdom which it useth in all
other things also, and that in such sort, as that
no violent force or course therein appeareth. 8
Notwithstanding these wise and enlightened
maxims, it must be owned, on the other hand,
that Bodin has indulged himself in various spe¬
culations, which would expose a writer of the
present times to the imputation of insanity.
One of the most extraordinary of these, is his
elaborate argument to prove, that, in a w^ell con¬
stituted state, the father should possess the right
of life and death over his children ;—a paradox
which forms an unaccountable contrast to the
general tone of humanity which characterizes his
opinions. Of the extent of his credulity on the
subject of witchcraft, and of the deep horror
with which he regarded those who affected to be
sceptical about the reality of that crime, he has
left a lasting memorial in a learned and curious
volume entitled Demonomanie;5 * * while the ec-
1 Book iv. chap, iii The book from which this quotation is taken was published only twenty-three years after the mur¬
der of Servetus at Geneva ; an event which leaves so deep a stain on the memory not only of Calvin, but on that ot the
milder and more charitable Melanchthon. The epistle of the latter to Bullinger, where he applauds the conduct ot the
iudges who condemned to the flames this incorrigible heretic, affords the most decisive of all proofs, how remote the senti¬
ments of the most enlightened Fathers of the Reformation were from those Christian and philosophical principles ot tole-
ration, to which their noble exertions have gradually, and now almost universally, led the way. , .
2 IMd The substance of the above reflection has been compressed by Bacon into the following well-known aphorisms.
“ Time is the greatest innovator ; shall we then not imitate time ?
“ What innovator imitates time, which innovates so silently as to mock the sense ?”
The resemblance between the two passages is still more striking in the Latin versions of their respective authors. _
Deum igitur prsepotentem naturae parentem imitemur, qui omnia paulatim : namque semina perquam exigua m ar-
bores excelsas excrescere jubet, idque tarn occulte ut nemo sentiat.”—Bodinus.
“ Novator maximus tempus ; quidni igitur tempus imitemur ?”
“ Q,uis novator tempus imitatur, quod novationes ita insinuat, ut sensus fallant ?”—Bacon. _ . . ,
The Treatise of Bodin De la Republique (by far the most important of his works) was first printed at 1 aris in 7 , am
was reprinted seven times in the space of three years. It was translated into Latin by the author himsel ? '¥1 a view
chiefly (as is said) to the accommodation of the scholars of England, among whom it was so highly esteemed, t la ec uivs
upon it were given in the University of Cambridge, as early as 1580. In 1579, Bodin visited London in the sm e o le
Due d’Alencon ; a circumstance which probably contributed not a little to recommend his writings, so very £°on a er eir
publication,’to the attention of our countrymen. In 1606, the treatise of The Republic was done inlo English by Kichard
Knolles, who appears to have collated the French and Latin copies so carefully and judiciously, that his version is, in some
respects, superior to either of the originals. It is from this version, accordingly, that I have transenbed the passages above
quoted ; trusting, that it will not be unacceptable to my readers, while looking back to the intellectual attainments o our
forefathers, to have an opportunity, at the same time, of marking the progress which had been made in England, moie t tan
two centuries ago, in the arts of writing and of translation. _ _ „ at io'i
For Dr Johnson’s opinion of Knolles’s merits as an historian, and as an English writer, see the Rambler, ^o. i&s.
* De la Demonomanie des Sorciers. Par J. Bodin Angevin, a Paris, 1580. This book, which exhibits so melancholy
DISSERTATION FIRST.
20
cen tricity of his religious tenets was such, as to
incline the candid mind of Grotius to suspect
him of a secret leaning to the Jewish faith.1
In contemplating the characters of the eminent
persons who appeared about this era, nothing is
more interesting and instructive, than to remark
the astonishing combination, in the same minds,
of the highest intellectual endowments, with the
most deplorable aberrations of the understand¬
ing ; and even, in numberless instances, with the
most childish superstitions of the multitude.
Of this apparent inconsistency, Bodinus dues
not furnish a solitary example. The same re¬
mark may be extended, in a greater or less de¬
gree, to most of the other celebrated names
hitherto mentioned. Melanchthon, as appears
from his letters, was an interpreter of dreams,
and a caster of nativities; * and Luther not only
sanctioned, by his authority, the popular fables
about the sexual and prolific intercourse of Satan
with the human race, but seems to have serious¬
ly believed that he had himself frequently seen
the arch enemy face to face, and held arguments
with him on points of theology.5 Nor was the
study of the severer sciences, on all occasions,
an effectual remedy against such illusions of the
imagination. The sagacious Kepler was an as¬
trologer and a visionary ; and his friend Tycho
Brahe, the Prince of Astronomers, kept an idiot in
his service, to whose prophecies he listened as
revelations from above.4 During the long night
of Gothic barbarism, the intellectual world had
again become, like the primitive earth, “ with¬
out form and voidthe light had already ap¬
peared ; ii and God had seen the light that it was
goodbut the time was not yet come to “ di¬
vide it from the darkness.”5
In the midst of the disorders, both political
and moral, of that unfortunate age, it is pleasing
to observe the anticipations of brighter pro¬
spects, in the speculations of a few individuals.
Bodinus himself is one of the number;6 and to
his name may be added that of his countryman
and predecessor Budseus.7 But, of all the
writers of the sixteenth century, Ludovicus
Vives seems to have had the liveliest and the
a contrast to the mental powers displayed in the treatise De la Repullique, was dedicated by the author to his friend, the
President de Thou; and it is somewhat amusing to find, that it exposed Bodin himself to the imputation of being a nia-
o-ician. For this we have the testimony of the illustrious historian just mentioned—(Thuavus, Lib. cxvii- ix.)—Nor did it
recommend the author to the good opinion of the Catholic church, having been formally condemned and prohibited by the
Roman Inquisition. The Reflection of the Jesuit Martin del Rio on this occasion is worth transcribing. “ Adeo lubricum
et periculosum de his disserere, nisi Deum semper, et catholicam Jidem, ecclesiceqne Romance censuram tanquam cynosuram sequaris."—
Disquisitionum Magicarum, Libri Sex. Auctore Martino del Rio, Societatis Jesu Presbytero. Yenit. 1640, p. 8.
1 Epist. ad Cordesium (quoted by Bayle.)
2 Jortin’s Life of Erasmus, p. 156.
3 See Note E.
* See the Life of Tycho Brahe, by Gassendi. _ _
5 I have allotted to Bodin a larger space than may seem due to his literary importance; but the truth is, I know of no
political writer, of the same date, whose extensive and various and discriminating reading appears to me to have contri¬
buted more to facilitate and to guide the researches of his successors, or whose references to ancient learning have been
more frequently transcribed without acknowledgment. Of late his works have fallen into very general^ neglect; otherwise
it is impossible that so many gross mistakes should be current about the scope and spirit of his principles. By many he
has been mentioned as a zealot for republican forms of government, probably for no better reason than that he chose to call
his book a Treatise De Republica; whereas, in point of fact, he is uniformly a warm and able advocate for monarchy ; and,
although no friend to tyranny, has, on more than one occasion, carried his monarchical principles to a very blameable ex¬
cess JSee, in particular, chapters fourth and fifth of the Sixth Book.) On the other hand, Grouvelle, a writer of some
note, has classed Bodin with Aristotle, as an advocate for domestic slavery. “ The reasonings of both,” he says, “ are re¬
futed by Montesquieu.” (De VAutorite, de Montesquieu dans la Revolution presente. Paris, 1789.) _ Whoever has the
curiosity to compare Bodin and Montesquieu together, will be satisfied, that, on this point, their sentiments were exactly
the same; and that, so far from refuting Bodin, Montesquieu has borrowed from him more than one argument in support
of his general conclusion. ,.
The merits of Bodin have been, on the whole, very fairly estimated by Bayle, who pronounces lam one of the ablest
men-that appeared in France during the sixteenth century.” “ Si nous voulons disputer h Jean Bodin la qualitd d’ecnvain
exact et iudicieux, laissons lui sans controverse, un grand genie, un vaste savoir, une me'moire et une lecture prodigieuses.
* See, in particular, his Method of Studying History, chap. vii. entitled Confutatio eorum qui quatuor Monarchies Aureaquc
Scecula statuerunt. In this chapter, after enumerating some of the most important discoveries and inventions of the moderns,
he concludes with mentioning the art of printing, of the value of which he seems to have formed a very just estimate.
“ Una Typographia cum omnibus veterum inventis certare facile potest. Itaque non minus peccant, qui a vetenbus
aiunt omnia comprehensa, quam qui illos de veten multarum artium possessione deturbant. Habet Natura scientiarum
thesauros innumerabiles, qui nullis aetatibus exhauriri possunt.” In the same chapter Bodinus expresses himseil tnus :
“ Alt as ilia quam auream vocant, si ad nostram conferatur,/ermi videri possit.” _ . , .
i The works of Budseus were printed at Basle, in four volumes folio, 1557. My acquaintance^ with them is muen too
slight to enable me to speak of them from my own judgment. No scholar certainly stood higher in the estimation oi n s
age. “ Quo viro,” says Ludovicus Yives, “ Gallia acutiore ingenio, acriroe judicio, exaction? dihgentia, majore eruui-
tione nullum unquam produxit; hac vero setate nec Italia quidem.” The praise bestowed on him by o er con e p 3
writers of the highest eminence is equally lavish.
30
PRELIMINARY DISSERTATIONS.
most assured foresight of the new career on
which the human mind was about to enter.
The following passage from one of his works
would have done no discredit to the Novum Or¬
ganon :—“ The similitude which many have
fancied between the superiority of the moderns
to the ancients, and the elevation of a dwarf on
the back of a giant, is altogether false and puerile.
Neither were they giants, nor are we dwarfs, hut
all of us men of the same standard,—and we the
taller of the two, by adding their height to our
own : Provided always that we do not yield to
them in study, attention, vigilance, and love of
truth ; for, if these qualities he wanting, so far
from mounting on the giant’s shoulders, we throw
away the advantages of our own just stature, by
remaining prostrate on the ground.”1 2
I pass over, without any particular notice, the
names of some French logicians who flourished
about this period, because, however celebrated
among their contemporaries, they do not seem
to form essential links in the History of Science.
The hold and persevering spirit with which Ra¬
mus disputed, in the University of Paris, the
authority of Aristotle, and the persecutions he
incurred by this philosophical heresy, entitle
him to an honourable distinction from the rest
of his brethren. He was certainly a man of un¬
common acuteness as well as eloquence, and
placed in a very strong light some of the most
vulnerable parts of the Aristotelian logic; with¬
out, however, exhibiting any marks of that deep
sagacity which afterwards enabled Bacon, Des¬
cartes, and Locke, to strike at the very roots
of the system. His copious and not inelegant
style as a writer, recommended his innovations
to those who were disgusted with the barbarism
of the schools;8 while his avowed partiality for
the reformed faith (to which he fell a martyr in
the massacre of Paris), procured many prose¬
lytes to his opinions in all the Protestant coun¬
tries of Europe. In England his logic had the
honour, in an age of comparative light and re¬
finement, to find an expounder and methodiser
in the author of Paradise Lost; and in some of
our northern universities, where it was very
early introduced, it maintained its ground till it
was supplanted by the logic of Locke.
It has been justly said of Ramus, that, “ al¬
though he had genius sufficient to shake the
Aristotelian fabric, he was unable to substitute
any thing more solid in its placehut it ought
not to he forgotten, that even this praise, scanty
as it may now appear, involves a large tribute
to his merits as a philosophical reformer. Be¬
fore human reason was able to advance, it was
necessary that it should first he released from
the weight of its fetters.3 * * * *
1 Vives de Cans. Corrupt. Artium, Lib. i. Similar ideas occur in the works of Roger Bacon : “ Quanto juniores tanto
perspicaciores, quia juniores posteriores successione temporum ingrediuntur labores priorum.”—(Opus Majus, edit. Jebb.
p. 9.) Nor were they altogether overlooked by ancient waiters. “ Yeniet tempus, quo ista quae latent nunc in lucem
dies extrahet, et longioris aevi diligentia. Yeniet tempus, quo poster! nostri tam aperta nos ignorasse mirabuntur.”
(Seneca, Qucest. Nat. Lib. vii. c. 25.) This language coincides exactly with that of the Chancellor Bacon ; but it was re¬
served for the latter to illustrate the connection between the progress of human knowledge, and of human happiness ; or (to
borrow his own phraseology) the connection between the progress of knowledge, and the enlargement of man’s power over
the destiny of his own species. Among other passages to this purpose, See Nov. Org. Lib. i. cxxix.
2 To the accomplishments of Ramus as a writer, a very flattering testimony is given by an eminent English scholar, by
no means disposed to overrate his merits as a logician. “ Pulsa tandem barbarie, Petrus Ramus politioris literaturae vir,
ausus est Aristotelem acrius ubique et liberius incessere, universamque Peripateticam philosophiam exagitare. Ejus
Dialetica exiguo tempore fuit apud plurimos summo in pretio, maxime eloquentiae studiosos, idque idio scholasticorum,
quorum dictio et stylus ingrata fuerant auribus Ciceronianis.”—Logicce Artis Compendium, Auctore R. Sanderson, Episc.
Lincoln, pp. 250. 251. Edit. Decima. Oxon. The first edition was printed in 1618.
3 Dr Barrow, in one of his mathematical lectures, speaks of Ramus in terms far too contemptuous. “ Homo, ne quid
gravius dicam, argutulus et dicacnlus."—“ Sane vix indignationi meae tempero, quin ilium accipiam pro suo merito, regeram-
que validius in ejus caput, quae contra veteres jactat convicia.” Had Barrow confined this censure to the weak and arro¬
gant attacks made by Ramus upon Euclid (particularly upon Euclid’s definition of Proportion), it would not have been
more than Ramus deserved ; but it is evident he meant to extend it also to the more powerful attacks of the same reformer
upon the logic of Aristotle. Of these there are many which may be read with profit even in the present times. I select
one passage as a specimen, recommending it strongly to the consideration of those logicians who have lately stood forward
as advocates for Aristotle’s abecedarian demonstrations of the syllogistic rules. “ In Aristotelis arte, unius pnecepti uni-
cum exemplum est, ac ssepissime nullum : sed unico et singular! exemplo non potest artifex effici; pluribus opus est et
dissimilibus. Et quidem, ut Aristotelis exempla tantummodo non falsa sint, qualia tamen sunt ? Omne 6 est a : omne c est
b : ergo omne c est a. Exemplum Aristotelis est puero a grammaticis et oratoribus venienti, et istam mutorum Mathema-
ticorum linguam ignoranti, novum et durum: et in totis Analyticis ista non Attica, non lonica, non Dorica, non vEolica,
non communi, sed geometrica lingua usus est Aristoteles, odiosa pueris, ignota populo, a communi sensu remota, a rhetoricse
usu et ab humanitatis usu alienissima.”—(P. Rami pro Philosophica Parisiensis Academia; Disciplina Oratio, 1550). If these
strictures should be thought too loose and declamatory, the reader may consult the fourth chapter (De Conversionibus) of the
seventh Look of Ramus’s Dialectics, where the same charge is urged, in my opinion, with irresistible force of argument.
DISSERTATION FIRST.
31
It is observed with great truth, hy Condorcet,
that, in the times of which we are now speak-
ing, £< the science of political economy did not
exist. Princes estimated not the number of
men, hut of soldiers in the state;—finance was
merely the art of plundering the people, with¬
out driving them to the desperation that might
end in revolt;—and governments paid no other
attention to commerce hut that of loading it
with taxes, of restricting it hy privileges, or of
disputing for its monopoly.”
The internal disorders then agitating the
whole of Christendom, were still less favourable
to the growth of this science, considered as a
branch of speculative study. Religious con¬
troversies everywhere divided the opinions of
the multitude;—involving those collateral dis¬
cussions concerning the liberty of conscience,
and the relative claims of sovereigns and sub¬
jects, which, by threatening to resolve society
into its first elements, present to restless and
aspiring spirits the most inviting of all fields for
enterprise and ambition. Amidst the shock of
such discussions, the calm inquiries which medi¬
tate in silence the slow and gradual amelioration
of the social order, were not likely to possess
strong attractions, even to men of the most
sanguine benevolence; and, accordingly, the po¬
litical speculations of this period turn almost en¬
tirely on the comparative advantages and disad¬
vantages of different forms of government, or
on the still more alarming questions concerning
the limits of allegiance and the right of resist¬
ance.
The dialogue of our illustrious countryman
Buchanan, De Jure Regni apud Scotos, though
occasionally disfigured by the keen and indig¬
nant temper of the writer, and by a predilection
(pardonable in a scholar warm from the schools
of ancient Greece and Rome) for forms of policy
unsuitable to the circumstances of modern
Europe, bears, nevertheless, in its general spirit,
a closer resemblance to the political philosophy
of the eighteenth century, than any composition
which had previously appeared. The ethical
paradoxes afterwards inculcated by Hobbes as
the ground-work of his slavish theory of govern¬
ment, are anticipated and refuted, and a power¬
ful argument is urged against that doctrine of
Utility which has attracted so much notice in
our times. The political reflections, too, inci¬
dentally introduced by the same author in his
History of Scotland, bear marks of a mind
worthy of a better age than fell to his lot. Of
this kind are the remarks with which he closes
his narrative of the wanton cruelties exercised
in punishing the murderers of James the First.
In reading them, one would almost imagine, that
one is listening to the voice of Beccaria or of
Montesquieu. {£ After this manner,” says the
historian, u was the cruel death of James still
more cruelly avenged. For punishments so far
exceeding the measure of humanity, have less
effect in deterring the multitude from crimes,
than in rousing them to greater efforts, both as
actors and as sufferers. Nor do they tend so
much to intimidate by their severity, as by their
frequency to diminish the terrors of the specta¬
tors. The evil is more peculiarly great, when
the mind of the criminal is hardened against the
sense of pain; for in the judgment of the un¬
thinking vulgar, a stubborn confidence generally
obtains the praise of heroic constancy.”
After the publication of this great work, the
name of Scotland, so early distinguished over
Europe by the learning and by the fervid genius1
of her sons, disappears for more than a century
and a half from the History of Letters. But
from this subject, so pregnant with melancholy
and humiliating recollections, our attention is
forcibly drawn to a mighty and auspicious light
which, in a more fortunate part of the island,
was already beginning to rise on the philosophi¬
cal world.2
1 Praefervidum Scotorum ingenium.
. that, at the end of the sixteenth century, the Scottish nation were advancing not less rapidly than their neighbours,
in every species of mental cultivation, is sufficiently attested by their literary remains, both in the Latin language and in
then- own vernacular tongue. A remarkable testimony to the same purpose occurs in the dialogue above quoted, the author
of which had spent the best years of his life in the most polished society of the Continent. “ As often,” says Buchanan,
as I turn my eyes to the niceness and elegance of our own times, the ancient manners of our forefathers appear sober and
venerable, but withal rough and horrid.”—“ Quoties oculosad nostri temporis munditiaset elegantiam refero, antiquitas ilia
sancta et sobiia, sed horrida tamen, et nondum satis expolita fuisse videtur.”—(De Jure Regni apud Scotos.') One would think,
that he conceived the taste of his countrymen to have then arrived at the ne plus ultra of national refinement,
Aurea nunc, olim sylvestribus horrida dumis.
32
PRELIMINARY DISSERTATIONS.
CHAPTER II.
FROM THE PUBLICATION OF BACON’S PHILOSOPHICAL WORKS, TILL THAT OF THE ESSAY
ON HUMAN UNDERSTANDING-
SECTION I.
Progress of Philosophy in England during this period.
BACON.1
The state of science towards the close of the
sixteenth century, presented a field of observa¬
tion singularly calculated to attract the curio¬
sity, and to awaken the genius of Bacon; nor
was it the least of his personal advantages, that,
as the son of one of Queen Elizabeth’s ministers,
he had a ready access, wherever he went, to the
most enlightened society in Europe. While yet
only in the seventeenth year of his age, he was
removed by his father from Cambridge to Paris,
where it is not to be doubted, that the novelty
of the literary scene must have largely contri¬
buted to cherish the natural liberality and inde¬
pendence of his mind. Sir Joshua Reynolds
has remarked, in one of his academical Dis¬
courses, that “ every seminary of learning is
surrounded with an atmosphere of floating
knowledge, where every mind may imbibe some¬
what congenial to its own original concep¬
tions.” * He might have added, with still great¬
er truth, that it is an atmosphere, of which it is
more peculiarly salutary for those who have
been elsewhere reared to breathe the air. The
remark is applicable to higher pursuits than
were in the contemplation of this philosophical
artist; and it suggests a hint of no inconsider¬
able value for the education of youth.
The merits of Bacon, as the father of Experi¬
mental Philosophy, are so universally acknow¬
ledged, that it would be superfluous to touch
upon them here. The lights which he has struck
out m various branches of the Philosophy of
Mind, have been much less attended to; al¬
though the whole scope and tenor of his specu¬
lations show, that to this study his genius was
far more strongly and happily turned, than to
that of the Material World. It was not, as some
seem to have imagined, by sagacious anticipa¬
tions of particular discoveries afterwards to be
made in physics, that his writings have had so
powerful an influence in accelerating the ad¬
vancement of that science. In the extent and
accuracy of his physical knowledge, he was far
inferior to many of his predecessors; but he
surpassed them all in his knowledge of the laws,
the resources, and the limits of the human un¬
derstanding. The sanguine expectations with
which he looked forwards to the future, were
founded solely on his confidence in the untried
capacities of the mind, and on a conviction of
the possibility of invigorating and guiding, by
means of logical rules, those faculties which, in
all our researches after truth, are the organs or
instruments to be employed. “ Such rules,” as
he himself has observed, <c do in some sort equal
men’s wits, and leave no great advantage or pre¬
eminence to the perfect and excellent motions
of the spirit. To draw a straight line, or to de¬
scribe a circle, by aim of hand only, there must
be a great difference between an unsteady and
unpractised hand, and a steady and practised ;
but to do it by r ule or compass it is much alike.”
1 Born 1561, died 1626.
Discourse delivered at the opening of the Royal Academy, January 2, 1769.
DISSERTATION FIRST.
33
Nor is it merely as a logician that Bacon is
entitled to notice on the present occasion. It
would be difficult to name another writer prior
to Locke, whose works are enriched with so
many just observations on the intellectual phe¬
nomena. Among these, the most valuable re¬
late to the laws of Memory, and of Imagination;
the latter of which subjects he seems to have
studied with peculiar care. In one short hut
beautiful paragraph concerning Poetry (under
which title may be comprehended all the vari¬
ous creations of this faculty), he has exhausted
every thing that philosophy and good sense have
yet had to offer, on what has been since called
the Beau Ideal; a topic, which has furnished
occasion to so many over-refinements among
the French critics, and to so much extravagance
and mysticism in the cloud-clapt metaphysics of
the new German school.1 In considering ima¬
gination as connected with the nervous system,
more particularly as connected with that species
of sympathy to which medical writers have
given the mime of imitation^ he has suggested
some very important hints which none of his
successors have hitherto prosecuted; and has,
at the same time, left an example of cautious
inquiry, worthy to be studied by all who may
attempt to investigate the laws regulating the
union between Mind and Body.2 His illustra¬
tion of the different classes of prejudices inci¬
dent to human nature, is, in point of practical
utility, at least equal to any thing on that head
to be found in Locke, of whom it is impossible
to forbear remarking, as a circumstance not
easily explicable, that he should have resumed
this important discussion, without once mention¬
ing the name of his great predecessor. The
chief improvement made by Locke, in the far¬
ther prosecution of the argument, is the appli¬
cation of Hobbes’s theory of association, to ex¬
plain in what manner these prejudices are ori¬
ginally generated.
In Bacon’s scattered hints on topics connected
with the Philosophy of the Mind, strictly so
called, nothing is more remarkable than the pre¬
cise and just ideas they display of the proper
aim of this science. He had manifestly re¬
flected much and successfully on the operations
of his own understanding, and had studied with
uncommon sagacity the intellectual characters
of others. Of his reflections and observations
on both subjects, he has recorded many im¬
portant results, and has in general stated them
without the slightest reference to any physiolo¬
gical theory concerning their causes, or to any
analogical explanations founded on the caprices
of metaphorical language. If, on some occasions,
he assumes the existence of animal spirits, as the
medium of communication between Soul and
Body, it must be remembered, that this was
then the universal belief of the learned; and that
it was at a much later period not less confidently
avowed by Locke. Nor ought it to be over¬
looked (I mention it to thecredit of both authors),
1 “ Cum mumlus sensibilis sit anima rational! dignitate inferior, videtur Potsis haec humanae naturae largiri quae historia
denegat; atque animo umbris rerum utcunque satisfacere, cum solida haberi non possint. Si quis enim rem acutius in-
trospiciat, firmum ex Po'Csi sumitur argumentum, magnitudinem rerum magis illustrem, ordinem magis perfectum, et va-
rietatem magis pulchram, animae human® complacere, quam in natura ipsa, post lapsun^ reperiri ullo modo possit. Qua-
propter, cum res gest® et eventus, qui ver® histori® subjiciuntur, non sint ejus amplitudinis, in qua anima humana sibi
satisfaciat, pr®sto est PoUtis, qu® facta magis heroica confingat. Cum historia vera successus rerum, minime pro mentis
virtutum et seelerum narret, corrigit earn Po'eris, et exitus, et fortunas, secundum merita, et ex lege Nemeseos, exhibet.
Cum historia vera obvia rerum satietate et similitudine, anim® human® fastidio sit reficit earn Potsis, inexpectata, et
varia, et vicissitudinum plena canens. Adeo ut Potsis ista non solum ad delectationem, sed ad animi magnitudinem, et ad
mores conferat.”—t De Aug. Sclent. Lib. ii. cap. xiii.)
2 To this branch of the philosophy of mind, Bacon gives the title of Doctrina de feedere, sive de communi vinculo animae et
corporis CDe Aug. Sclent. Lib. iv. cap. i.) Under this article, he mentions, among other desiderata, an inquiry (which he
recommends to physicians) concerning the influence of imagination over the body. His own words are very remarkable ;
more particularly, the clause in which he remarks the effect of fixing and concentrating the attention, in giving to ideal
objects the power of realities over the belief. “ Ad aliud quippiam, quod hue pertinet, parce admodum, nec pro rei sub-
tilitate, vel utilitate, inquisitum est; quatenus scilieet ipsa imagimtio animae vel cogitatio perquam Jixa, et vcluti in Jidem
quondam cxaltata. valeat ad immutandum corpus imaginantis.”—(Ibid.) He suggests also, as a curious problem, to ascer¬
tain how far it is possible to fortify and exalt the imagination ; and by what means this may most effectually be done.
The class of facts here alluded to, are manifestly of the same description with those to which the attention of philosophers
has been lately called by the pretensions of Mesmer and of Perkins: “ Atque huic conjuncta est disquisitio, quomodo ima-
ginatio intend! et fortificari possit ? Quippe, si imaginatio fortis tantarum sit virium, oper® pretium fuerit nosse, quibus
modis earn exaltari, et se ipsa majorem fieri detur ? Atque hie oblique, nec minus periculose se msinuat palliatio qu®dam
et defensio maxim® partis Magicc Ceremonialis," &c. &c.—Dc Aug. Sclent. Lib. iv. cap. iii.
MSS. I. PART I. E
34
PRELIMINARY DISSERTATIONS.
that in such instances the fact is commonly so
stated, as to render it easy for the reader to de¬
tach it from the theory. As to the scholastic
questions concerning the nature and essence of
mind,—whether it he extended or unextended ?
whether it have any relation to space or to time ?
or whether (as was contended by others) it exist
in every ubi, but in no place ?—Bacon has uni¬
formly passed them over with silent contempt;
and has probably contributed not less effectually
to bring them into general discredit, by this in¬
direct intimation of his own opinion, than if he
had descended to the ungrateful task of exposing
their absurdity.1
While Bacon, however, so cautiously avoids
these unprofitable discussions about the nature
of Mind, he decidedly states his conviction, that
the faculties of Man differ not merely in degree,
but in kind, from the instincts of the brutes.
“ I do not, therefore,” he observes on one oc¬
casion, “ approve of that confused and promiscu¬
ous method in which philosophers are accustomed
to treat of pneumatology; as if the human Soul
ranked above those of brutes, merely like the
sun above the stars, or like gold above other
metals.”
Among the various topics started by Bacon
for the consideration of future logicians, he did
not overlook (what may be justly regarded, in
a practical view, as the most interesting of all
logical problems) the question concerning the
mutual influence of Thought and of Language
on each other. “ Men believe,” says he, “ that
their reason governs their words; but it often
happens, that words have power enough to re¬
act upon reason.” This aphorism may be con¬
sidered as the text of by far the most valuable
part of Locke’s Essay,—that which relates to
the imperfections and abuse of words; but it
was not until within the last twenty years that
its depth and importance were perceived in all
their extent. I need scarcely say, that I allude
to the excellent Memoirs of M. Prevost and of
M. Degerando, on “ Signs considered in their
connection with the Intellectual Operations.”
The anticipations formed by Bacon, of that branch
of modern logic which relates to Universal Gram¬
mar, do no less honour to his sagacity. “ Gram¬
mar,” he observes, “ is of two kinds, the one lite¬
rary, the other philosophical. The former has
for its object to trace the analogies running
through the structure of a particular tongue, so
as to facilitate its acquisition to a foreigner, or to
enable him to speak it with correctness and purity.
The latter directs the attention, not to the analogies
which words bear to words, but the analogies
which words bear to things;”2 or, as he after¬
wards explains himself more clearly, {{ to lan¬
guage considered as the sensible portraiture or
image of the mental process.” In farther illus¬
tration of these hints, he takes notice of the lights
which the different genius of different languages
reflect on the characters and habits of those by
whom they were respectively spoken. <c Thus,”
says he, “ it is easy to perceive, that the
Greeks were addicted to the culture of the arts,
the Romans engrossed with the conduct of af¬
fairs ; inasmuch as the technical distinctions
introduced in the progress of refinement require
the aid of compounded words; while the real
business of life stands in no need of so artificial
a phraseology.”3 Ideas of this sort have, in the
course of a very few years, already become com¬
mon, and almost tritical; but how different was
the case two centuries ago !
With these sound and enlarged views con¬
cerning the philosophy of the Mind, it will not
appear surprising to those who have attended to
the slow and irregular advances of human reason,
that Bacon should occasionally blend incidental
1 Notwithstanding the extravagance of Spinoza’s own philosophical creed, he is one of the very few among Bacon’s
successors, who seem to have been fully aware of the justness, importance, and originality of the method pointed out in
the Novum Organon for the study of the Mind. “ Ad hsec intelligenda, non est opus naturam mentis cognoscere, sed suf-
ficit, mentis sive perceptionum historiolam concinnare modo illo quo Verulamius docet.”—Spin. Epist. 42.
In order to comprehend the whole merit of this remark, it is necessary to know that, according to the Cartesian phrase¬
ology, which is here adopted by Spinoza, the word perception is a general term, equally applicable to all the intellectual
operations. The words of Descartes himself are these : “ Omnes modi cogitandi, quos in nobis experimur, ad duos gene-
rales referri possunt: quorum unus est, perceptio, sive operatio intellectus; alius vero, volitio, sive operatic voluntatis.
Nam sentiri, imaginari, et pure intelligere, sunt tantum diversi modi percipiendi; ut et cupere, aversari, affirmare, negare,
dubitare, sunt diversi modi volendi.”—Princip. Phil. Pars I. § 32.
* De Aug. Sclent. Lib. vi. can. i.
* Ibid.
DISSERTATION FIRST.
35
remarks, savouring of the habits of thinking
prevalent in his time. A curious example of
this occurs in the same chapter which contains
his excellent definition or description of uni¬
versal grammar. “ This too,” he observes, “ is
worthy of notice, that the ancient languages
were full of declensions, of cases, of conjugations,
of tenses, and of other similar inflections; while
the modern, almost entirely destitute of these,
indolently accomplish the same purpose by the
help of prepositions, and of auxiliary verbs.
Whence,” he continues, “ may be inferred,
(however we may flatter ourselves with the idea
of our own superiority), that the human intellect
was much more acute and subtile in ancient, than
it now is in modern times.”1 How very un¬
like is this last reflection to the usual strain of
Bacon’s writings ! It seems, indeed, much more
congenia* to tne pm.osopny of Mr Harris and of
Lord Monboddo; and it has accordingly been
sanctioned with the approbation of both these
earned authors. If my memory does not deceive
me, it is the omy passage in Bacon’s works,
which Lord Monboddo has anywhere conde¬
scended to quote.
These observations afford me a convenient
opportunity for remarking the progress and dif¬
fusion of the philosophical spirit, since the begin¬
ning of the seventeenth century. In the short
passage just cited from Bacon, there are involv¬
ed no less than two capital errors, which are
now almost universally ranked, by men of edu¬
cation, among the grossest prejudices of the
multitude. The one, that the declensions and
conjugations of the ancient languages, and the
modern substitution in their place of preposi¬
tions and auxiliary verbs, are, both of them, the
deliberate and systematical contrivances of spe¬
culative grammarians; the other (still less ana¬
logous to Bacon’s general style of reasoning),
that the faculties of man have declined, as the
world has grown older. Both of these errors
may be now said to have disappeared entirely.
The latter, more particularly, must, to the ris¬
ing generation, seem so absurd, that it almost
requires an apology to have mentioned it. That
the capacities of the human mind have been in
all ages the same; and that the diversity of
phenomena exhibited by our species, is the re¬
sult merely of the different circumstances in
which men are placed, has been long receiv¬
ed as an incontrovertible logical maxim. or ra¬
ther, such is the influence of early instruction,
that we are apt to regard it as one of the most
obvious suggestions of common sense. And
yet, till about the time of Montesquieu, it was
by no means so generally recognised by the
learned, as to have a sensible influence on the
fashionable tone of thinking over Europe. The
application of this fundamental and leading idea
to the natural theoi etical history of society in
all its various aspects ;—to the history of lan¬
guages, of the arts, of the sciences, of laws, of
government, of manners, and of religion,—is
the peculiar glory of the latter half of the eigh¬
teenth century, and forms a characteristica
feature in its philosophy, which even the ima¬
gination of Bacon was unable to foresee.
It would be endless to particularize the ori¬
ginal suggestions thrown out by Bacon on topics
connectea with the science of Mind. The few
passages of this sort already quoted, are produ¬
ced merely as a specimen of the rest. They are
by no means selected as the most important in
his writings; but as they happened to be those
which had left the strongest impression on my
memory, I thought them as likely as any other,
to invite the curiosity of my readers to a careful
examination of the rich mine from which they
are extracted.
The Ethical disquisitions of Bacon are almost
entirely of a practical nature. Of the two theo¬
retical questions so much agitated, in both parts
of this island, during the eighteenth century,
concerning the principle and the object of moral
approbation, he has said nothing; but he has
opened some new and interesting views with re¬
spect to the influence of custom and the forma¬
tion of habits ;—a most important article of mo¬
ral philosophy, on which he has enlarged more
ably and more usefully than any writer since
Aristotle.2 Under the same head of Ethics may
De Aug. Scient. Lib- vi. cap. i.
De Aug. Scient. Lib. vii. cap. iii.
36
PRELIMINARY DISSERTATIONS.
be mentioned the small volume to which he has
given the title of Essays ; the best known and
the most popular of all his works. It is also
one of those where the superiority of his genius
appears to the greatest advantage; the novelty
and depth of his reflections often receiving a
strong relief from the triteness of his subject.
It may be read from beginning to end in a few
hours,—and yet, after the twentieth perusal,
one seldom fails to remark in it something over¬
looked before. This, indeed, is a characteristic
of all Bacon’s writings, and is only to be ac¬
counted for by the inexhaustible aliment they
furnish to our own thoughts, and the sympa¬
thetic activity they impart to our torpid faculties.
The suggestions of Bacon for the improve¬
ment of Political Philosophy, exhibit as strong
a contrast to the narrow systems of contempo¬
rary statesmen, as the Inductive Logic to that
of the Schools. How profound and comprehen¬
sive are the views opened in the following pas¬
sages, when compared with the scope of the cele¬
brated treatise De Jure Belli et Pacts; a work
which was first published about a year before
Bacon’s death, and which continued, for a hun¬
dred and fifty years afterwards, to be regarded
in all the Protestant universities of Europe as
an inexhaustible treasure of moral and jurispru¬
dential wisdom !
“ The ultimate object which legislators ought
to have in view, and to which all their enact¬
ments and sanctions ought to be subservient, is,
that the citizens may live happily. For this pur¬
pose, it is necessary that they should receive a
religious and pious education; that they should
be trained to good morals; that they should be
secured from foreign enemies by proper mili¬
tary arrangements; that they should be guard¬
ed by an effectual police against seditions and
private injuries; that they should be loyal to
government, and obedient to magistrates; and,
finally, that they should abound in wealth, and
in other national resources.”1—“ The science
of such matters certainly belongs more parti¬
cularly to the province of men who, by habits
of public business, have been led to take a com¬
prehensive survey of the social order; of the in¬
terests of the community at large; of the rules
of natural equity; of the manners of nations;
of the different forms of government; and who
are thus prepared to reason concerning the wis¬
dom of laws, both from considerations of jus¬
tice and of policy. The great desideratum,
accordingly, is, by investigating the principles
of natural justice, and those of political expedi¬
ency, to exhibit a theoretical model of legisla¬
tion, which, while it serves as a standard for
estimating the comparative excellence of muni¬
cipal codes, may suggest hints for their correc¬
tion and improvement, to such as have at heart
the welfare of mankind.”2 3 *
How precise the notion was that Bacon had
formed of a philosophical system of jurispru¬
dence (with which as a standard the municipal
laws of different nations might be compared),
appears from a remarkable expression, in which
he mentions it as the proper business of those
who might .attempt to carry his plan into execu¬
tion, to investigate those “ leges legum, ex
quibus informatio peti possit, quid in singulis
legibus bene aut perperam positum aut consti-
tutum sit.”5 I do not know if, in Bacon’s
1 Exemphnn Tractatm de Fontibus Juris, Aphor. 5. This enumeration of the different objects of law approaches very
nearly to Mr Smith’s ideas on the same subject, as expressed by himself in the concluding sentence of his Theory of Moral
Sentiments. “ In another Discourse, I shall endeavour to give an account of the general principles of law and govern¬
ment, and of the different revolutions they have undergone in the different ages and periods of society; not only in what
concerns justice, but in what concerns police, revenue, and arms, and whatever else is the object of law.”
4 De Aug. Sclent. Lib. viii. cap. iii.
3 De Fontibus Juris, Aphor. 6.
From the preface to a small tract of Bacon’s entitled, The Elements of the Common Laws of England, written while he was
Solicitor-General to Queen Elizabeth, we learn, that the phrase legum leges had been previously used by some “ great
Civilian.” To what Civilian Bacon here alludes, I know not; but, whoever he was, I doubt much if he annexed to it the
comprehensive and philosophical meaning so precisely explained in the above definition. Bacon himself, when he wrote
his Tract on the Common Laws, does not seem to have yet risen to this vantage-ground of Universal Jurisprudence. His
great object (he tells us) was “ to collect the rules and grounds dispersed throughout the body of the same laws, in order
to see more profoundly into the reason of such judgments and ruled cases, and thereby to make more use of them for the
decision of other cases more doubtful; so that the uncertainty of'law, which is the principal and most just challenge that is
made to the laws of our nation at this time, will, by this new*strength laid to the foundation, be somewhat the more settled
and corrected.” In this passage, no reference whatever is made to the Universal Justice spoken of in the aphorisms De
Fontilus Juris ; but merely to the leading and governing rules which give to a municipal system whatever it possesses of
DISSERTATION FIRST.
37
prophetic anticipations of the future progress of
Physics, there he any thing more characteristi-
cal, both of the grandeur and of the justness of
his conceptions, than this short definition; more
particularly, when we consider how widely Gro-
tius, in a work professedly devoted to this very
inquiry, was soon after to wander from the
right path, in consequence of his vague and
wavering idea of the aim of his researches.
The sagacity, however, displayed in these, and
various other passages of a similar import, can
by no means be duly appreciated, without at¬
tending, at the same time, to the cautious and
temperate maxims so frequently inculcated by
the author, on the subject of political innova¬
tion. “ A stubborn retention of customs is a
turbulent thing, not less than the introduction
of new.”—“ Time is the greatest innovator;
shall we then not imitate time, which innovates
so silently as to mock the sense ?” Nearly con¬
nected with these aphorisms, are the profound
reflections in the first book De Augmentis Scien-
tiarum, on the necessity of accommodating every
new institution to the character and circum¬
stances of the people for whom it is intended;
and on the peculiar danger which literary men
run of overlooking this consideration, from the
familiar acquaintance they acquire, in the course
of their early studies, with the ideas and senti¬
ments of the ancient classics.
The remark of Bacon on the systematical
policy of Henry VII. was manifestly suggested
by the same train of thinking. “ His laws
(whoso marks them well) were deep and not
vulgar; not made on the spur of a particular
occasion for the present, but out of providence
for the future; to make the estate of his people
still more and more happy, after the manner of
the legislators in ancient and heroic times.”
How far this noble eulogy was merited, either
by the legislators of antiquity, or by the modern
Prince on whom Bacon has bestowed it, is a
question of little moment. I quote it merely on
account of the important philosophical distinc¬
tion which it indirectly marks, between “ deep
and vulgar laws;” the former invariably aiming
to accomplish their end, not by giving any sud¬
den shock to the feelings and interests of the
existing generation, but by allowing to natural
causes time and opportunity to operate; and
by removing those artificial obstacles which
check the progressive tendencies of society. It
is probable, that, on this occasion, Bacon had
an eye more particularly to the memorable sta¬
tute of alienation; to the effects of which (what¬
ever were the motives of its author) the above
description certainly applies in an eminent de¬
gree.
After all, however, it must be acknowledged,
that it is rather in his general views and maxims,
than in the details of his political theories, that
Bacon’s sagacity appears to advantage. His
notions with respect to commercial policy seem
to have been more peculiarly erroneous; origi¬
nating in an overweening opinion of the efficacy
of law, in matters where natural causes ought
to be allowed a free operation. It is observed
by Mr Hume, that the statutes of Henry VII. re¬
lating to the police of his kingdom, are generally
contrived with more judgment than his com¬
mercial regulations. The same writer adds, that
“ the more simple ideas of order and equity are
sufficient to guide a legislator in every thing that
regards the internal administration of justice;
but that the principles of commerce are much
more complicated, and require long experience
and deep reflection to be well understood in any
state. The real consequence is there often con¬
trary to first appearances. No wonder, that,
during the reign of Henry VII., these matters
were frequently mistaken ; and it may safely be
affirmed, that, even in the age of Lord Bacon,
very imperfect and erroneous ideas were formed
on that subject.”
The instances mentioned by Hume in con¬
firmation of these general remarks, are pe¬
culiarly gratifying to those who have a pleasure
in tracing the slow but certain progress of rea¬
son and liberality. “ During the reign,” says
he, “ of Henry VII. it was prohibited to ex¬
analogy and consistency. To these rules Bacon gives the title of leges legnm; but the meaning of the phrase, on this oc¬
casion, differs from that in which he afterwards employed it, not less widely than the rules of Latin or of Greek syntax
differ from the principles of universal grammar.
38
PRELIMINARY DISSERTATIONS.
port horses, as if that exportation did not en¬
courage the breed, and make them moie plen¬
tiful in the kingdom. Prices were also affixed
to woollen cloths,to caps and hats, and the wages
of labourers were regulated by law. It is evi¬
dent, that these matters ought always to he leftfree,
and he entrusted to the common course of business
and commerce.^“ For a like reason,’ the his¬
torian continues, the <£ law enacted against in¬
closures, and for the keeping up of farm-houses,
scarcely deserves the praises bestowed on it by
Lord Bacon. If husbandmen understand agri¬
culture, and have a ready vent for their com¬
modities, we need not dread a diminution of the
people employed in the country. During a cen¬
tury and a half after this period, there was a
frequent renewal of laws and edicts against de¬
population ; whence we may infer, that none of
them were ever executed. The natural course
of improvement at last provided a remedy.”
These acute and decisive strictures on the im¬
policy of some laws highly applauded by Bacon,
while they strongly illustrate the narrow and
mistaken views in political economy entertained
by the wisest statesmen and philosophers two
centuries ago, afford, at the same time, a proof
of the general diffusion which has since taken place
among the people of Great Britain, of juster and
more enlightened opinions on this important
branch of legislation. Wherever such doctrines
find their way into the page of history, it may
he safely inferred, that the public mind is not
indisposed to give them a welcome reception.
The ideas of Bacon concerning the education
of youth, were such as might he expected from
a philosophical statesman. On the conduct of
education in general, with a view to the de-
velopement and improvement of the intellectual
character, he has suggested various useful hints
in different parts of his works; hut what I wish
chiefly to remark at present is, the paramount
importance which he has attached to the education
of the people,—comparing, as he has repeatedly
done, the effects of early culture on the un¬
derstanding and the heart, to the abundant har¬
vest which rewards the diligent husbandman for
the toils of the spring. To this analogy he seems
to have been particularly anxious to attract the
attention of his readers, by bestowing on educa¬
tion the title of the Georgies of the Mind; iden¬
tifying, by a happy and impressive metaphor, the
two proudest functions entrusted to the legi¬
slator,—the encouragement of agricultural in¬
dustry, and the care of national instruction. In
both instances, the legislator exerts a power
which is literally productive or creative; com¬
pelling, in the one case, the unprofitable desert
to pour forth its latent riches; and in the other,
vivifying the dormant seeds of genius and virtue,
and redeeming from the neglected wastes of hu¬
man intellect, a new and unexpected accession
to the common inheritance of mankind.
When from such speculations as these we
descend to the treatise JDe Jure Belli et Pads, the
contrast is mortifying indeed. And yet, so
much better suited were the talents and accom¬
plishments of Grotius to the taste, not only of
his contemporaries, hut of their remote descend¬
ants, that, while the merits of Bacon failed, for
a century and a half, to command the general
admiration of Europe,1 Grotius continued, even
in our British universities, the acknowledged
Oracle of J urisprudence and of Ethics, till long
after the death of Montesquieu. Nor was Bacon
himself unapprised of the slow growth of his
posthumous fame. No writer seems ever to have
felt more deeply, that he properly belonged to a
later and more enlightened age;—a sentiment
which he has pathetically expressed in that clause
of his testament where he “ bequeaths his name
to posterity, after some generations shall he
past.”2
Unbounded, however, as the reputation of
Grotius was on the Continent, even before his
own death, it was not till many years after the
publication of the treatise De Jure Belli et Pacist
that the science of Natural Jurisprudence became,
in this island, an object of much attention, even
1 “ La celdbrit^ en France des ecrits du Chancelier Bacon n’a guere pour date que celle de I’Encyclopedie. —(Histoire
de.s Mathematiqties par Montucla, Preface, p. ix.) It is an extraordinary circumstance, that Bayle, who has so oitcn wasted
his erudition and acuteness on the most insignificant characters, and to whom Le Clerc has very justly asenbed the merit
of une exactitude etonnante dans des chases de neant, should have devoted to Bacon only twelve lines of his Dictionary.
B See* Note F.
DISSERTATION FIRST.
39
to the learned. In order, therefore, to give to
the sequel of this section some degree of con¬
tinuity, I shall reserve my observations on Gro-
tius and his successors, till I shall have finished
all that I think it necessary to mention further,
with respect to the literature of our own coun¬
try, prior to the appearance of Mr Locke’s
Essay.
The rapid advancement of intellectual culti¬
vation in England, between the years 1588 and
1640 (a period of almost uninterrupted peace),
has been remarked by Mr Fox. “ The general
improvement,” he observes, “ in all arts of civil
life, and, above all, the astonishing progress of
literature, are the most striking among the gene¬
ral features of that period; and are in themselves
causes sufficient to produce effects of the utmost
importance. A country whose language was en¬
riched by the works of Hooker, Raleigh, and Ba¬
con, could not but experience a sensible change
in its manners, and in its style of thinking; and
even to speak the same language in which Spen¬
cer and Shakspeare had written, seemed a suf¬
ficient plea to rescue the Commons of England
from the appellation of Brutes, with which Hend¬
ry the Eighth had addressed them.”—The re¬
mark is equally just and refined. It is by the
mediation of an improving language, that the
progress of the mind is chiefly continued from
one generation to another ; and that the acquire¬
ments of the enlightened few are insensibly im¬
parted to the many. Whatever tends to diminish
the ambiguities of speech, or to fix, with more
logical precision, the import of general terms ;—
above all, whatever tends to embody, in popular
forms of expression, the ideas and feelings of the
wise and good, augments the natural powers
of the human understanding, and enables the
succeeding race to start from a higher ground
than was occupied by their fathers. The remark
applies with peculiar force to the study of the
Mind itself; a study, where the chief source of
error is the imperfection of words; and where
every improvement on this great instrument of
thought may be justly regarded in the light of
a discovery.1
In the foregoing list of illustrious names, Mr
Fox has, with much propriety, connected those
of Bacon and Raleigh; two men, who, not¬
withstanding the diversity of their professional
pursuits, and the strong contrast of their cha¬
racters, exhibit, nevertheless, in their capacity
of authors, some striking features of resem¬
blance. Both of them owed to the force of their
own minds, their emancipation from the fetters
of the schools; both were eminently distinguish¬
ed above their contemporaries, by the originality
and enlargement of their philosophical views ;
and both divide, with the venerable Hooker,
the glory of exemplifying, to their yet unpolish¬
ed countrymen, the richness, variety, and grace,
which might be lent to the English idiom, by
the hand of a master.1'
It is not improbable that Mr Fox might have
included the name of Hobbes in the same enu¬
meration, had he not been prevented by an
aversion to his slavish principles of government,
and by his own disrelish for metaphysical theories.
As a writer, Hobbes unquestionably ranks high
among the older English classics, and is so pe¬
culiarly distinguished by the simplicity and ease
of his manner, that one would naturally have
expected from Mr Fox’s characteristical taste,
1 It is not so foreign as may at first be supposed to the object of this Discourse, to take notice here of the extraordinary
demand for books on Agriculture, under the government of James I. The fact is thus very strongly stated by Dr Johnson,
in his introduction to the Harleian Miscellany. “ It deserves to be remarked, because it is not generally known, that the
treatises on husbandry and agriculture, which were published during the reign of King James, are so numerous, that it can
scarcely be imagined by whom they were written, or to whom they were sold.” Nothing can illustrate more strongly the
effects of a pacific system of policy, in encouraging a general taste for reading, as well as an active spirit of national im¬
provement. At all times, and in every country, the extensive sale of looks on agriculture, may be regarded as one of the
most pleasing symptoms of mental cultivation in the great body of a people.
* To prevent being misunderstood, it is necessary for me to add, that I do not speak of the general style of these old au¬
thors ; but only of detached passages, which may be selected from all of them, as earnests or first fruits of a new and
brighter era in English literature. It may be safely affirmed, that in works, and in the prose compositions of Milton,
are to.be found some of the finest sentences of which our language has yet to boast. To propose them now as models for
imitation would be quite absurd. Dr I.owth certainly went much too far when he said, “ That in correctness, propriety,
&a& purity of English style, Hooker hath hardly been surpassed, or even equalled, by any of his successors.”—Preface to
Lowth’s English Grammar.
PRELIMINARY DISSERTATIONS.
40
that he would have relished his style still more
than that of Bacon1 or of Raleigh. It is with
the philosophical merits, however, of Hobbes,
that we are alone concerned at present; and, in
this point of view, what a space is filled in the
subsequent history of our domestic literature,
by his own works, and by those of his innume¬
rable opponents ! Little else, indeed, hut the
systems which he published, and the contro¬
versies which they provoked, occurs, during the
interval between Bacon and Locke, to mark the
progress of English Philosophy, either in the
study of the Mind, or in the kindred researches
of Ethical and Political Science.
Of the few and comparatively trifling excep¬
tions to this remark, furnished by the metaphy¬
sical tracts of Glanville, of Henry More, and
of John Smith, I must delay taking notice, till
some account shall be given of the Cartesian
Philosophy; to which their most interesting dis¬
cussions have a constant reference, either in the
way of comment or refutation.
HOBBES.*
« The philosopher of Malmesbury,” says Dr
Warburton, “ was the terror of the last age, as
Tindall and Collins are of this. The press
sweat with controversy; and every young
churchman militant, would try his arms in
thundering on Hobbes’s steel cap. 5 Nor was
the opposition to Hobbes confined to the clerical
order, or to the controversialists of his own
times. The most eminent moralists and politi¬
cians of the eighteenth century may be ranked
in the number of his antagonists; and even at
the present moment, scarcely does there appear
a new publication on Ethics or Jurisprudence,
where a refutation of Hobbism is not to be found.
The period when Hobbes began his literary
career, as well as the principal incidents of his
life, were, in a singular degree, favourable to a
mind like his; impatient of the yoke of autho¬
rity, and ambitious to attract attention, if not
by solid and useful discoveries, at least by an
ingenious defence of paradoxical tenets. After
a residence of five years at Oxford, and a very
extensive tour through France and Italy, he
had the good fortune, upon his return to Eng¬
land, to be admitted into the intimacy and con¬
fidence of Lord Bacon ; a circumstance which,
we may presume, contributed not a little to en¬
courage that bold spirit of inquiry, and that
aversion to scholastic learning, which character¬
ise his writings. Happy, if he had, at the same
time, imbibed some portion of that love of truth
and zeal for the advancement of knowledge,
which seem to have been Bacon s ruling pas¬
sions ! But such was the obstinacy of his tem¬
per, and his overweening self-conceit, that, in¬
stead of co-operating with Bacon in the execu¬
tion of his magnificent design, he resolved to
rear, on a foundation exclusively his own, a com¬
plete structure both of Moral and Physical
Science; disdaining to avail himself even of the
materials collected by his predecessors, and
treating the experimentarian philosophers as ob¬
jects only of contempt and ridicule !4
In the political writings of Hobbes, we may
perceive the influence also of other motives.
From his earliest years, he seems to have been
1 According to Dr Burnet (no contemptible judge of style), Bacon was„ the first t la | works of Sprat
The same learned prelate pronounces Bacon to be “ still our best author ; and this, at a ■ (];ppicuit to
and many of the prose compositions of Cowley and of Dryden, were already in the han » o , Pf ' t> ,g 'prans-
conceive on what grounds Burnet proceeded, in hazarding so extraordinary an opinion—See p
It is still more difficult, on the other hand, to account for the following very bold decision of Mr Hume.^1
it from an essay first published in 1742 ; but the same passage is to be found in the last edit Locke and
bv himself. “ The first polite prose we iiave, was writ by a man (Dr Swift) who is still aliv . -r JL.i ’ Harrington
even Temple, they knew too little of the rules of art to be esteemed elegant writers. The prose , g ’
and Milton, is altogether stiff and pedantic, though their sense be excellent.”   tnpvhmistible
How insignificant are the petty grammatical improvements proposed by Swift, whe11 ^ aUh the hi her qua_
riches imparted to the English tongue by the writers of the seventeenth century; and how inter , Addison '
lities and graces of style, are his prose compositions, to those of his immediate predecessors, Dryden, p ,
2 Born 1588, died 1679.
3 Divine Legation, Pref. to Vol. II. p. 9.
4 See Note G.
DISSERTATION FIRST.
41
decidedly hostile to all the forms of popular go¬
vernment ; and it is said to have been with the
design of impressing his countrymen with a just
sense of the disorders incident to democratical
establishments, that he published, in 1618, an
English translation of Thucydides. In these
opinions he was more and more confirmed by
the events he afterwards witnessed in England;
the fatal consequences of which he early foresaw
with so much alarm, that, in 1640, he withdrew
from the approaching storm, to enjoy the so¬
ciety of his philosophical friends at Paris. It
was there he wrote his book De Give, a few
copies of which were printed, and privately
circulated in 1642. The same work was after¬
wards given to the public, with material cor¬
rections and improvements, in 1647, when the
author’s attachment to the royal cause being
strengthened by his personal connection with the
exiled king, he thought it incumbent on him
to stand forth avowedly as an advocate for those
principles which he had long professed. The
great object of this performance was to strength¬
en the hands of sovereigns against the rising
spirit of democracy, by arming them with the
weapons of a new philosophy.
The fundamental doctrines inculcated in the
political works of Hobbes are contained in the
following propositions. I recapitulate them
here, not on their own account, but to prepare
the way for some remarks which I mean after¬
wards to offer on the coincidence between the
principles of Hobbes and those of Locke. In
their practical conclusions, indeed, with re¬
spect to the rights and duties of citizens, the
two writers differ widely; but it is curious to
observe how very nearly they set out from the
same hypothetical assumptions.
All men are by nature equal; and, prior to
government, they had all an equal right to en¬
joy the good things of this world. Man, too, is
(according to Hobbes) by nature a solitary and
purely selfish animal; the social union being en¬
tirely an interested league, suggested by pruden¬
tial views of personal advantage. The necessary
consequence is, that a state of nature must be a
state of perpetual warfare, in which no indivi¬
dual has any other means of safety than his own
strength or ingenuity ; and in which there is no
room for regular industry, because no secure en¬
joyment of its fruits. In confirmation of this
view of the origin of society, Hobbes appeals to
facts falling daily within the circle of our own
experience. “ Does not a man (he asks), when
taking a journey, arm himself, and seek to go
well accompanied ? When going to sleep, does
he not lock his doors ? Nay, even in his own
house, does he not lock his chests ? Does he
not there as much accuse mankind by his actions,
as I do by my words ?”1 An additional argu¬
ment to the same purpose may, according to
some later Hobhists, be derived from the in¬
stinctive aversion of infants for strangers; and
from the apprehension which, it is alleged,
every person feels, when he hears the tread of
an unknown foot in the dark.
For the sake of peace and security, it is ne¬
cessary that each individual should surrender a
part of his natural right, and be contented with
such a share of liberty as he is willing to allow
to others; or, to use Hobbes’s own language,
“ every man must divest himself of the right he
has to all things by nature ; the right of all men
to all things being in effect no better than if no
man had a right to any thing.”2 In conse¬
quence of this transference of natural rights to
an individual, or to a body of individuals, the
multitude become one person, under the name
of a State or Republic, by which person the
common will and power are exercised for the
common defence. The ruling power cannot be
withdrawn from those to whom it has been com¬
mitted ; nor can they be punished for misgovern-
ment. The interpretation of the laws is to be
sought, not from the comments of philosophers,
hut from the authority of the ruler ; otherwise
society would eA^ery moment be in danger of re¬
solving itself into the discordant elements of
which it was at first composed. The will of the
magistrate, therefore, is to be regarded as theulti-
1 Of Man, Part I. chap. xiii.
2 De Corpore Politico, Part I chap. i. § 10.
DISS. 1. PART I.
42
PRELIMINARY DISSERTATIONS.
mate standard of right and wrong, and his voice
to be listened to by every citizen as the voice of
conscience.
Not many years afterwards,1 Hobbes pushed
the argument for the absolute power of princes
still farther, in a work to which he gave the
name of Leviathan. Under this appellation he
means the body politic ; insinuating that man is
an untameable beast of prey, and that govern¬
ment is the strong chain by which he is kept
from mischief. The fundamental principles here
maintained are the same as in the hook De Give;
but as it inveighs more particularly against ec¬
clesiastical tyranny, with the view of subjecting
die consciences of men to the civil authority, it
lost the author the favour of some powerful pro¬
tectors he had hitherto enjoyed among the Eng¬
lish divines who attended Charles II. in France ;
and he even found it convenient to quit that
kingdom, and to return to England, where Crom¬
well (to whose government his political tenets
were now as favourable as they were meant to be
to the royal claims) suffered him to remain un¬
molested. The same circumstances operated to
his disadvantage after the Restoration, and
obliged the King, who always retained for him
a very strong attachment, to confer his marks
of favour on him with the utmost reserve and
circumspection.2
The details which I have entered into, with
respect to the history of Hobbes’s political writ¬
ings, will be found, by those who may peruse
them, to throw much light on the author’s reason¬
ings. Indeed, it is only by thus considering
them in their connection with the circumstances
of the times, and the fortunes of the writer,
that a just notion can be formed of their spirit
and tendency.
The ethical principles of Hobbes are so com¬
pletely interwoven with his political system,
that all which has been said of the one may be
applied to the other. It is very remarkable,
that Descartes should have thought so highly
of the former, as to pronounce Hobbes to be
“ a much greater master of morality than of
metaphysics;” a judgment which is of itself
sufficient to mark the very low state of ethical
science in France about the middle of the seven¬
teenth century. Mr Addison, on the other
hand, gives a decided preference (among all the
books written by Hobbes) to his Treatise on Hu¬
man Nature ; and to his opinion on this point I
most implicitly subscribe ; including, however,
in the same commendation, some of his other
philosophical essays on similiar topics. They
are the only part of his works which it is pos¬
sible now to read with any interest; and they
everywhere evince in their author, even when
he thinks most unsoundly himself, that power
of setting his reader a-thinking, which is one of
the most unequivocal marks of original genius.
They have plainly been studied with the utmost
care both by Locke and Hume. To the former
they have suggested some of his most important
observations on the Association of Ideas, as well
as much of the sophistry displayed in the first
book of his Essay, on the Origin of our Know¬
ledge, and on the factitious nature of our moral
principles; to the latter (among a variety of
hints of less consequence), his theory concern¬
ing the nature of those established connections
among physical events, which it is the business
of the natural philosopher to ascertain,3 and the
substance of his argument against the scho¬
lastic doctrine of general conceptions. It is from
the works of Hobbes, too, that our later Neces¬
sitarians have borrowed the most formidable of
those weapons with which they have combated
the doctrine of moral liberty; and from the
same source has been derived the leading idea
1 In 1651.
2 See Note H.
3 The same doctrine, concerning the proper object of natural philosophy (commonly ascribed to Mr Hume, both by his
followers and by his opponents), is to be found in various writers contemporary with Hobbes. It is stated, with uncom¬
mon precision and clearness, in a book entitled Scepsis Scientifica, or Confessed Ignorance the way to Science, by Joseph
Glanvill, (printed in 1665). The whole work is strongly marked with the features of an acute, an original, and, in matters
of science, a somewhat sceptical genius; and, when compared with the treatise on witchcraft, by the same author, adds
another proof to those already mentioned, of the possible union of the highest intellectual gifts with the most degrading
intellectual weaknesses.
With respect to the Scepsis Scientifica, it deserves to be noticed, that the doctrine maintained in it concerning physical
causes and effects does not occur in the form of a detached observation, of the value of which the author might not have
been fully aware, but is the very basis of the general argument running through all his discussions.
DISSERTATION FIRST.
43
which runs through the philological materialism
of Mr Horne Tooke. It is probable, indeed,
that this last author borrowed it, at second¬
hand, from a hint in Locke’s Essay; but it is
repeatedly stated by Hobbes, in the most ex¬
plicit and confident terms. Of this idea (than
which, in point of fact, nothing can be imagin¬
ed more puerile and unsound), Mr Tooke’s
etymologies, when he applies them to the solu¬
tion of metaphysical questions, are little more
than an ingenious expansion, adapted and level¬
led to the comprehension of the multitude.
The speculations of Hobbes, however, con¬
cerning the theory of the understanding, do not
seem to have been nearly so much attended to
during his own life, as some of his other doc¬
trines, which, having a more immediate refer¬
ence to human affairs, were better adapted to
the unsettled and revolutionary spirit of the
times. It is by these doctrines, chiefly, that his
name has since become so memorable in the an¬
nals of modern literature; and although they
now derive their whole interest from the extra¬
ordinary combination they exhibit of acuteness
and subtlety with a dead-palsy in the powers of
taste and of moral sensibility, yet they will be
found, on an attentive examination, to have had
a far more extensive influence on the subsequent
history, both of political and of ethical science,
than any other publication of the same period.
ANTAGONISTS OF HOBBES.
Cudworth1 was one of the first who success¬
fully combated this new philosophy. As Hobbes,
in the frenzy of his political zeal, had been led
to sacrifice wantonly all the principles of re¬
ligion and morality to the establishment of his
conclusions, his works not only gaATe offence to
the friends of liberty, but excited a general
alarm among all sound moralists. His doctrine,
in particular, that there is no natural distinction
between Right and Wrong, and that these are
dependent on the arbitrary will of the civil ma¬
gistrate, was so obviously subversive of all the
commonly received ideas concerning the moral
constitution of human nature, that it became in¬
dispensably necessary, either to expose the so¬
phistry of the attempt, or to admit, with Hobbes,
that man is a beast of prey, incapable of being
governed by any motives but fear, and the de¬
sire of self-preservation.
Between some of these tenets of the courtly
Hohbists, and those inculcated by the Cromwel¬
lian Antinomians, there was a very extraor¬
dinary and unfortunate coincidence; the latter
insisting, that, in expectation of Christ’s second
coming, “ the obligations of morality and natural
law were suspended; and that the elect, guided
by an internal principle, more perfect and divine,
were superior to the beggarly elements of justice
and humanity.”3 It was the object of Cudworth
to vindicate, against the assaults of both parties,
the immutability of moral distinctions.
In the prosecution of his very able argument
on this subject, Cudworth displays a rich store
of enlightened and choice erudition, penetrated
throughout with a peculiar vein of sobered and
subdued Platonism, from whence some German
systems, which have attracted no small notice
in our own times, will be found, when stripped
of their deep neological disguise, to have bor¬
rowed their most valuable materials.3
' Born 1617, died 1668.
5 Hume—For a more particular account of the English Antinomians, See Mosheim, Vol. IY. p. 534, et seq.
3 The mind, according to Cudworth, perceives, by occasion of outward objects, as much more than is represented to it
by sense, as a learned man does in the best written book, than an illiterate person or brute. “ To the eyes of both, the
same characters will appear; but the learned man, in those characters, will see heaven, earth, sun, and stars ; read pro¬
found theorems of philosophy or geometry; learn a great deal of new knowledge from them, and admire the wisdom of
the composer; while, to the other, nothing appears but black strokes drawn on white paper. The reason of which is,
that the mind of the one is furnished with certain previous inward anticipations, ideas, and instruction, that the other
wants.”—“ In the room of this book of human composition, let us now substitute the book of Nature, written all
over with the characters and impressions of divine wisdom and goodness, but legible only to an intellectual eye. To the
sense both of man and brute, there appears nothing else in it, but, as in the other, so many inky scrawls ; that is, nothing
but figures and colours. But the mind, which hath a participation of the divine wisdom that made it, upon occasion of
those sensible delineations, exerting its own inward activity, will have not only a wonderful scene, and large prospects of
44
PRELIMINARY DISSERTATIONS.
Another coincidence between the Hohbists
and the Antinomians, may he remarked in their
common zeal for the scheme of necessity ; which
both of them stated in such a way as to he
equally inconsistent with the moral agency of
man, and with the moral attributes of God.1
The strongest of all presumptions against this
scheme is afforded by the other tenets with
which it is almost universally combined; and ac¬
cordingly, it was very shrewdly observed by
Cudworth, that the licentious system which flou¬
rished in his time (under which title, I pre¬
sume, he comprehended the immoral tenets of
the fanatics as well as of the Hobbists), “ grew
up from the doctrine of the fatal necessity of all
actions and events, as from its proper root.”
The unsettled, and, at the same time, disputa¬
tious period during which Cudworth lived, af¬
forded him peculiarly favourable opportunities
of judging from experience, of the practical ten¬
dency of this metaphysical dogma; and the re¬
sult of his observations deserves the serious at¬
tention of those who may be disposed to regard
it in the light of a fair and harmless theme for
the display of controversial subtility. To argue,
in this manner, against a speculative principle
from its palpable effects, is not always so illogi¬
cal as some authors have supposed. “ You re¬
peat to me incessantly,” says Rousseau to one
of his correspondents, 4 4 that truth can never be
injurious to the world. I myself believe so as
firmly as you do; and it is for this very reason
I am satisfied that your proposition is false.”2
But the principal importance of Cudworth, as
an ethical writer, arises from the influence of
his argument concerning the immutability of
right and wrong on the various theories of mo¬
rals which appeared in the course of the eigh¬
teenth century. To this argument may, more
particularly, he traced the origin of the cele¬
brated question, Whether the principle of moral
approbation is to be ultimately resolved into
Reason, or into Sentiment ?—a question which
has furnished the chief ground of difference be¬
tween the Systems of Cudworth and of Clarke,
on the one hand; and those of Shaftesbury,
Hutcheson, Hume, and Smith, on the other.
The remarks which I have to offer on this con¬
troversy must evidently be delayed, till the writ¬
ings of these more modern authors shall fall un¬
der review.
The Intellectual System of Cudworth embraces
a field much wider than his treatise of Immu¬
table Morality. The latter is particularly direct¬
ed against the ethical doctrines of Hobbes, and
of the Antinomians; but the former aspires to
tear up by the roots all the principles, both phy¬
sical and metaphysical, of the Epicurean philo¬
sophy. It is a work, certainly, which reflects
much honour on the talents of the author, and
still more on the boundless extent of his learn¬
ing ; but it is so ill suited to the taste of the
present age, that, since the time of Mr Harris
and Dr Price, I scarcely recollect the slightest
reference to it in the writings of our British me¬
taphysicians. Of its faults (beside the general
disposition of the author to discuss questions
placed altogether beyond the reach of our facul¬
ties), the most prominent is the wild hypothesis
of a plastic nature ; or, in other words, 44 of a
vital and spiritual, but unintelligent and neces¬
sary agent, created by the Deity for the execu-
other thoughts laid open before it, and variety of knowledge, logical, mathematical, and moral, displayed ; but also clearly
read the divine wisdom and goodness in every page of this great volume, as it were written in large and legible characters.”
I do not pretend to be an adept in the philosophy of Kant; but I certainly think I pay it a very high compliment, when
I suppose, that, in the Critic of Pure Reason, the leading idea is somewhat analogous to what is so much better expressed in
the foregoing passage. To Kant it was probably suggested by the following very acute and decisive remark of Leibnitz on
Locke’s Essay : “ Nempe, nihil est in intellectu, quod non fuerit in sensu, nisi ipse intellectus.”
In justice to Aristotle, it may be here observed, that, although the general strain of his language is strictly conformable
to the scholastic maxim just quoted, he does not seem to have altogether overlooked the important exception to it pointed
out by Leibnitz. Indeed, this exception or limitation is very nearly a translation of Aristotle’s words. Ka) uLrog Ss Co vs)
vatiTOi Itrnv, wrong ra vonra' Ivri fiv yag rwv clviu ro abro hrn voovv, ku) to imoufiivtiv. “ And the mind itself is an object of
knowledge, as well as other things which are intelligible. For, in immaterial beings, that which understands is the same
with that which is understood.”—(De A?iima, Lib. iii. cap. iv.) I quote this very curious, and, I suspect, very little
known sentence, in order to vindicate Aristotle against the misrepresentations of some of his present idolaters, who, in
their anxiety to secure to him all the credit of Locke’s doctrine concerning the origin of our ideas, have overlooked the
occasional traces which occur in his works, of that higher and sounder philosophy in which he had been educated.
1 “ The doctrines of fate or destiny were deemed by the Independents essential to all religion. In these rigid opinions,
the whole sectaries, amidst all their other differences, unanimously concurred.”—Hume’s History, chap. Ivii.
2 “ Vous repdtez sans cesse que la verite ne peut jamais faire de mal aux hommes; je le crois, et e’est pour moi la
preuve que ce que vous dites n’est pas la vdritd.”
DISSERTATION FIRST.
45
tion of his purposes.” Notwithstanding, how¬
ever, these, and many other abatements of its
merits, the Intellectual System will for ever re¬
main a precious mine of information to those
whose curiosity may lead them to study the spi¬
rit of the ancient theories; and to it we may
justly apply what Leibnitz has somewhere said,
with far less reason, of the works of the school¬
men, “ Scholasticos agnosco abundare ineptiis;
sed aurum est in illo cano.”1
Before dismissing the doctrines of Hobbes, it
may be worth while to remark, that all his lead¬
ing principles are traced by Cudworth to the re¬
mains of the ancient sceptics, by some of whom,
as well as by Hobbes, they seem to have been
adopted from a wish to flatter the uncontrolled
passions of sovereigns. Not that I am disposed
to call in question the originality o! Hobbes;
for it appears, from the testimony of all his
friends, that he had much less pleasure in read¬
ing than in thinking. “ If I had read,” he was
accustomed to say, “ as much as some others, I
should have been as ignorant as they are.” But
similar political circumstances invariably repro¬
duce similar philosophical theories; and it is
one of the numerous disadvantages attending an
inventive mind, not properly furnished with ac¬
quired information, to be continually liable to a
waste of its powers on subjects previously ex¬
hausted.
The sudden tide of licentiousness, both in
principles and in practice, which burst into this
island at the moment of the Restoration, con¬
spired with the paradoxes of Hobbes, and with
the no less dangerous errors recently propagated
among the people by their religious instructors,
to turn the thoughts of sober and speculative
men towards ethical disquisitions. The esta¬
blished clergy assumed a higher tone than be¬
fore in their sermons; sometimes employing
them in combating that Epicurean and Machia-
velian philosophy which was then fashionable at
court, and which may be always suspected to
form the secret creed of the enemies of civil and
religious liberty;—on other occasions, to over¬
whelm, with the united force of argument and
learning, the extravagances by which the igno¬
rant enthusiasts of the preceding period had ex¬
posed Christianity itself to the scoffs of their li¬
bertine opponents. Among the divines who ap¬
peared at this era, it is impossible to pass over
in silence the name of Barrow, whose theological
works (adorned throughout by classical erudition,
and by a vigorous, though unpolished eloquence),
exhibit, in every page, marks of the same inven¬
tive genius which, in mathematics, has secured to
him a rank second alone to that of Newton. As
a writer, he is equally distinguished by the re¬
dundancy of his matter, and by the pregnant
brevity of his expression; but what more pecu¬
liarly characterises his manner, is a certain air
of powerful and of conscious facility in the exe¬
cution of whatever he undertakes. Whether
the subject be mathematical, metaphysical, or
theological, he seems always to bring to it a
mind which feels itself superior to the occasion ;
and which, in contending with the greatest dif¬
ficulties, “ puts forth but half its strength.”
He has somewhere spoken of his Lectiones Ma~
thematicce (which it may, in passing, be remarked,
display metaphysical talents of the highest order),
as extemporaneous effusions of his pen; and I
have no doubt that the same epithet is still more
literally applicable to his pulpit discourses. It
is, indeed, only thus we can account for the va¬
riety and extent of his voluminous remains,
when we recollect that the author died at the
age of forty-six.2
To the extreme rapidity with which Barrow
committed his thoughts to writing, I am inclined
to ascribe the hasty and not altogether consist-
1 The Intellectual System was published in 1678. The Treatise concerning Eternal and Immutable Morality did not appear
till a considerable number of years after the author’s death. _
* In a note annexed to an English translation of the Cardinal Maury’s Principles of Eloquence, it is stated, upon the au¬
thority of a manuscript of Dr Doddridge, that most of Barrow’s sermons were transcribed three times, and some muc i
oftener. They seem to me to contain verv strong intrinsic evidence of the incorrectness of this anecdote. Mr ja am
Hill, in his Account of the Life of Barrow, addressed to Dr Tillotson, contents himself with saying,_ that “ Some ot his ser¬
mons were written four or five times over;”—mentioning, at the same time, a circumstance which may accoun or is
fact, in perfect consistency with what I have stated above,—that Barrow was very ready to lend his sermons as o en
desired.”
46
PRELIMINARY DISSERTATIONS.
ent opinions which he has hazarded on some im¬
portant topics. I shall confine myself to a single
example, which I select in preference to others,
as it hears directly on the most interesting of all
questions connected with the theory of morals.
“ If we scan,” says he, “ the particular nature,
and search into the original causes of the seve¬
ral kinds of naughty dispositions in our souls,
and of miscarriages in our lives, we shall find
inordinate self-love to be a main ingredient, and
a common source of them all; so that a divine
of great name had some reason to affirm,—that
original sin (or that innate distemper from which
men generally become so very prone to evil, and
averse to good), doth consist in self-love, dispo¬
sing us to all kinds of irregularity and excess.”
In another passage, the same author expresses
himself thus:—“ Reason dictateth and pre-
scribeth to us, that we should have a sober re¬
gard to our true good and welfare ; to our best
interests and solid content; to that which (all
things being rightly stated, considered, and com¬
puted) will, in the final event, prove most bene¬
ficial and satisfactory to us: a self-love working
in prosecution of such things, common sense
cannot hut allow and approve.”
Of these two opposite and irreconcileable opi¬
nions, the latter is incomparably the least wide
of the truth; and accordingly Mr Locke, and
his innumerable followers, both in England and
on the Continent, have maintained, that virtue
and an enlightened self-love are one and the
same. I shall afterwards find a more conve¬
nient opportunity for stating some objections to
the latter doctrine, as well as to the former. I
have quoted the two passages here, merely to
show the very little attention that had been
paid, at the era in question, to ethical science,
by one of the most learned and profound divines
of his age. This is the more remarkable, as his
works everywhere inculcate the purest lessons
of practical morality, and evince a singular
acuteness and justness of eye in the observation
of human character. Whoever compares the
views of Barrow, when he touches on the theory
of morals, with those opened about fifty years
afterwards by Dr Butler, in his Discourses on
Human Nature, will be abundantly satisfied,
that, in this science, as well as in others, the
progress of the philosophical spirit during the
intervening period was not inconsiderable.
The name of Wilkins (although he too wrote
with some reputation against the Epicureans of
his day), is now remembered chiefly in conse¬
quence of his treatises concerning a universal lan¬
guage and a real character. Of these treatises, I
shall hereafter have occasion to take some notice,
under a different article. With all the ingenuity
displayed in them, they cannot be considered as
accessions of much value to science; and the
long period since elapsed, during which no at¬
tempt has been made to turn them to any prac¬
tical use, affords of itself no slight presumption
against the solidity of the project.
A few years before the death of Hobbes, Dr
Cumberland (afterwards Bishop of Peterbo¬
rough) published a book, entitled, De Legibus
Natures, Disquisitio Philosophical the principal
aim of which was to confirm and illustrate, in
opposition to Hobbes, the conclusions of Grotius,
concerning Natural Law. The work is executed
with ability, and discovers juster views of the
object of moral science, than any modern sys¬
tem that had yet appeared; the author resting
the strength of his argument, not, as Grotius
had done, on an accumulation of authorities, but
on the principles of the human frame, and the
mutual relations of the human race. The cir¬
cumstance, however, which chiefly entitles this
publication to our notice, is, that it seems to
have been the earliest on the subject which at¬
tracted, in any considerable degree, the attention
of English scholars. From this time, the writings
of Grotius and of Puffendorff began to be gene¬
rally studied, and soon after made their way
into the Universities. In Scotland, the im¬
pression produced by them was more peculiarly
remarkable. They were everywhere adopted as
the best manuals of ethical and of political in¬
struction that could be put into the hands of
students, and gradually contributed to form that
memorable school, from whence so many philo¬
sophers and philosophical historians were after¬
wards to proceed.
From the writings of Hobbes to those of
Locke, the transition is easy and obvious; but
before prosecuting farther the history of philo¬
sophy in England, it will be proper to turn our
DISSERTATION FIRST.
47
attention to its progress abroad, since the period
at which this section commences.1 2 In the first
place, however, I shall add a few miscellaneous
remarks on some important events which oc¬
curred in this country during the lifetime of
Hobbes, and of which his extraordinary longe¬
vity prevented me sooner from taking notice.
Among these events, that which is most im¬
mediately connected with our present subject,
is the establishment of the Royal Society of
London in 1662, which was followed a few years
afterwards by that of the Royal Academy of
Sciences at Paris. The professed object of both
institutions was the improvement of Experi¬
mental Knowledge, and of the auxiliary science
of Mathematics; but their influence on the
general progress of human reason has been far
greater than could possibly have been foreseen
at the moment of their foundation. On the
happy effects resulting from them in this re¬
spect, La Place has introduced some just reflec¬
tions in his System of the World, which, as they
discover more originality of thought than he com¬
monly displays, when he ventures to step beyond
the circumference of his own magic circle, I shall
quote, in a literal translation of his words.
“ The chief advantage of learned societies, is
the philosophical spirit to which they may be ex¬
pected to give birth, and which they cannot fail
to diffuse over all the various pursuits of the
nations among whom they are established. The
insulated scholar may without dread abandon
himself to the spirit of system; he hears the
voice of contradiction only from afar. But in
a learned society, the collision of systematic
opinions soon terminates in their common de¬
struction ; while the desire of mutual conviction
creates among the members a tacit compact, to
admit nothing but the results of observation, or
the conclusions of mathematical reasoning. Ac¬
cordingly, experience has shown, how much
these establishments have contributed, since
their origin, to the spread of true philosophy.
By setting the example of submitting every
thing to the examination of a severe logic, they
have dissipated the prejudices which had too
long reigned in the sciences, and which the
strongest minds of the preceding centuries had
not been able to resist. They have constantly
opposed to empiricism a mass of knowledge,
against which the errors adopted by the vulgar,
with an enthusiasm which, in former times,
would have perpetuated their empire, have spent
their force in vain. In a word, it has been in
their bosoms that those grand theories have been
conceived, which, although far exalted by their
generality above the reach of the multitude, are
for this very reason entitled to special encourage¬
ment, from their innumerable applications to
the phenonema of nature, and to the practice of
the arts.”®
In confirmation of these judicious remarks, it
1 Throughout the whole of this Discourse, I have avoided touching on the discussions which, on various occasions, have
arisen with regard to the theory of government, and the comparative advantages or disadvantages of different political
forms. Of the scope and spirit of these discussions it would be seldom possible to convey a just idea, without entering
into details of a local or temporary nature, inconsistent with my general design. In the present circumstances of the
world, besides, the theory of government (although, in one point of view, the most important of all studies) seems to possess
a very subordinate interest to inquiries connected with political economy, and with the fundamental principles of legisla¬
tion. What is it, indeed, that renders one form of government more favourable than another to human happiness, but
the superior security it provides for the enactment of wise laws, and for their impartial and vigorous execution ? These
considerations will sufficiently account for my passing over in silence, not only the names of Needham, of Sidney, and of
Milton, but that of Harrington, whose Oceana is justly regarded as one of the boasts of English literature, and is pronounced
by Hume to be “ the only valuable model of a commonwealth that has yet been offered to the public.”—Essays and Trea¬
tises, Yol. I. Essay xvi.
A remark which Hume has elsewhere made on the Oceana, appears to me so striking and so instructive, that I shall give
it a place in this note. “ Harrington,” he observes, “ thought himself so sure of his general principle, that the balance of
power depends on that of property, that he ventured to pronounce it impossible ever to re-establish monarchy in England :
But his book was scarcely published when the King was restored ; and we see that monarchy has ever since subsisted on
the same footing as before. So dangerous is it for a politician to venture to foretell the situation of public affairs a few
years hence.”—Ibid. Essay vii.
How much nearer the truth, even in the science of politics, is Bacon’s cardinal principle, that knowledge is power !—a
principle, which applies to Man not less in his corporate than in his individual capacity ; and which may be safely trusted
to as the most solid of all foundations for our reasonings concerning the future history of the world.
2 The Royal Society of London, though not incorporated by charter till 1662, may be considered as virtually existing,
at least as far back as 1638, when some of the most eminent of the original members began first to hold regular meetings
at Gresham College, for the purpose of philosophical discussion. Even these meetings were but a continuation of those
previously held by the same individuals, at the apartments of Dr Wilkins in Oxford.—See Sprat’s History of the Royal
Society.
48
PRELIMINARY DISSERTATIONS.
may be farther observed, that nothing could
have been more happily imagined than the esta¬
blishment of learned corporations for correcting
those prejudices which (under the significant
title of Idola Specus), Bacon has described as in¬
cident to the retired student. While these idols
of the den maintain their authority, the cultiva¬
tion of the philosophical spirit is impossible; or
rather, it is in a renunciation of this idolatry
that the philosophical spirit essentially consists.
It was accordingly in this great school of the
learned world, that the characters of Bacon,
Descartes, Leibnitz, and Locke were formed ;
the four individuals who have contributed the
most to diffuse the philosophical spirit over
Europe. The remark applies more peculiarly
to Bacon, who first pointed out the inconveni¬
ences to be apprehended from a minute and
mechanical subdivision of literary labour ; and
anticipated the advantages to be expected from
the institution of learned academies, in enlar¬
ging the field of scientific curiosity, and the cor¬
respondent grasp of the emancipated mind. For
accomplishing this object, what means so effec¬
tual as habits of daily intercourse with men
whose pursuits are different from our own; and
that expanded knowledge, both of man and of
nature, of which such an intercourse must ne¬
cessarily be productive !
Another event which operated still more for¬
cibly and universally on the intellectual cha¬
racter of our countrymen, was the civil war
which began in 1640, and which ultimately
terminated in the usurpation of Cromwell. It
is observed by Mr Hume, that “ the prevalence
of democratical principles, under the Common¬
wealth, engaged the country gentlemen to bind
their sons apprentices to merchants; and that
commerce has ever since been more honourable
in England, than in any other European king¬
dom.”1 “ The higher and the lower ranks (as
a later winter has remarked) were thus brought
closer together, and all of them inspired with
an activity and vigour that, in former ages, had
no example.”2
To this combination of the pursuits of trade,
with the advantages of a liberal education, may
be ascribed the great multitude of ingenious and
enlightened speculations on commerce, and on
the other branches of national industry, which
issued from the press, in the short interval be¬
tween the Restoration and the Revolution ; an
interval during which the sudden and immense
extension of the trade of England, and the cor¬
responding rise of the commercial interest, must
have presented a spectacle peculiarly calculated
to awaken the curiosity of inquisitive observers.
It is a very remarkable circumstance with re¬
spect to these economical researches, which now
engage so much of the attention both of states¬
men and of philosophers, that they are altogether
of modern origin. “ There is scarcely,” says
Mr Hume, 11 any ancient writer on politics who
has made mention of trade; nor was it ever con¬
sidered as an affair of state till the seventeenth
century.”3—The work of the celebrated John de
Witt, entitled, “ The true interest and political
maxims of the republic of Holland and W est Fries¬
land,” is the earliest publication of any note, in
which commerce is treated of as an object of na¬
tional and politicalconcern,in opposition to the par¬
tial interests of corporations and of monopolists.
Of the English publications to which I have
just alluded, the greater part consists of anony¬
mous pamphlets, now only to be met with in the
collections of the curious. A few bear the
names of eminent English merchants. I shall
have occasion to refer to them more particularly
afterwards, when I come to speak of the writings
of Smith, Quesnay, and Turgot. At present,
I shall only observe, that, in these fugitive and
now neglected tracts, are to be found the first
rudiments of that science of Political Economy,
which is justly considered as the boast of the
present age; and which, although the aid of
learning and philosophy was necessary to rear it
to maturity, may he justly said to have had its
cradle in the Royal Exchange of London.
Mr Locke was one of the first retired theorists
(and this singular feature in his history has not
1 History of England, chap. Ixii.
2 Chalmehs’s Political Estimate, &c. (London, 1804) p. 44.
a Essay of Civil Liberty.
DISSERTATION FIRST.
49
been sufficiently attended toby his biographers),
who condescended to treat of trade as an object
of liberal study. Notwithstanding the manifold
errors into which he fell in the course of his
reasonings concerning it, it may be fairly ques¬
tioned, if he has anywhere else given greater
proofs, either of the vigour or of the originality
of his genius. But the name of Locke reminds
me, that it is now time to interrupt these nation¬
al details, and to turn our attention to the pro¬
gress of science on the Continent, since the times
of Bodinus and of Campanella.
SECTION II.
Progress of Philosophy in Prance during the Seventeenth Century.
MONTAIGNE—CHARRON—LA ROCHEFOUCAULD.
At the head of the French writers who con¬
tributed, in the beginning of the seventeenth
century, to turn the thoughts of their country¬
men to subjects connected with the Philosophy
of Mind, Montaigne may, I apprehend, be justly
placed. Properly speaking, he belongs to a
period somewhat earlier; but his tone of think¬
ing and of writing classes him much more natu¬
rally with his successors, than with any French
author who had appeared before him.1
In assigning to Montaigne so distinguished a
rank in the history of modern philosophy, I need
scarcely say, that I leave entirely out of the ac¬
count what constitutes (and justly constitutes)
to the generality of readers the principal charm
of his Essays; the good nature, humanity, and
unaffected sensibility, which so irresistibly attach
us to his character,—lending, it must be owned,
but too often a fascination to his talk, when he
cannot be recommended as the safest of com¬
panions. Nor do I lay much stress on the in¬
viting frankness and vivacity with which he un¬
bosoms himself about all his domestic habits and
concerns^ and which render his book so ex¬
pressive a portrait, not only of the author, but
of the Gascon country gentleman, two hundred
years ago. I have in view chiefly the minute¬
ness and good faith of his details concerning his
own personal qualities, both intellectual and mo¬
ral. The only study which seems ever to have
engaged his attention was that of man ; and for
this he was singularly fitted, by a rare com¬
bination of that talent for observation which be¬
longs to men of the world, with those habits of
abstracted reflection, which men of the world
have commonly so little disposition to cultivate.
“ I study myself,” says he, “ more than any
other subject. This is my metaphysic; this my
natural philosophy.” 2 He has accordingly pro¬
duced a work, unique in its kind; valuable, in
an eminent degree, as an authentic record of
many interesting facts relative to human nature;
but more valuable by far, as holding up a mirror
in which every individual, if he does not see his
own image, will at least occasionally perceive
so many traits of resemblance to it, as can scarce¬
ly fail to invite his curiosity to a more careful
review of himself. In this respect, Montaigne’s
writings may be regarded in the light of what
painters call studies; in other words, of those
slight sketches which were originally designed
for the improvement or amusement of the artist,
but which, on that account, are the more likely
to be useful in developing the germs of similar
endowments in others.
Withouta union of these two powers (reflection
' Montaigne was born in 1533, and died in 1592.
DISS. I. PART I.
2 Essays, Book iii. chap. xiii.
Cr
50
PRELIMINARY DISSERTATIONS.
and observation), the study of Man can never
be successfully prosecuted. It is only by re¬
tiring within ourselves that we can obtain a key
to the characters of others; and it is only by
observing and comparing the characters of others
that we can thoroughly understand and appre¬
ciate our own.
After all, however, it maybe fairly questioned,
notwithstanding the scrupulous fidelity with
which Montaigne has endeavoured to delineate
his own portrait, if he has been always sufficient¬
ly aware of the secret folds and reduplications
of the human heart. That he was by no means
exempted from the common delusions of self-love
and self-deceit, has been fully evinced in a very
acute, though somewhat uncharitable, section of
the Port-Royal logic; but this consideration, so
far from diminishing the value of his Essays, is
one of the most instructive lessons they afford to
those who, after the example of the author, may
undertake the salutary but humiliating task of
self-examination.
As Montaigne’s scientific knowledge was, ac¬
cording to his own account, <£ very vague and
imperfect,”1 and his book-learning rather sen¬
tentious and gossiping, than comprehensive and
systematical, it would be unreasonable to expect,
in his philosophical arguments, much either of
depth or of solidity.2 The sentiments he hazards
are to be regarded but as the impressions of the
moment; consisting chiefly of the more obvious
doubts and difficulties which, on all metaphysical
and moral questions, are apt to present them¬
selves to a speculative mind, when it first at¬
tempts to dig below the surface of common
opinions. In reading Montaigne, accordingly,
what chiefly strikes us, is not the novelty or the
refinement of his ideas, but the liveliness and
felicity with which we see embodied in words
the previous wanderings of our own imaginations.
It is probably owing to this circumstance, rather
than to any direct plagiarism, that his Essays
appear to contain the germs of so many of the
paradoxical theories which, in later times, Hel-
vetius and others have laboured to systematise
and to support with the parade of metaphysical
discussion. In the mind of Montaigne, the same
paradoxes may be easily traced to those deceitful
appearances which, in order to stimulate our
faculties to their best exertions, nature seems
purposely to have thrown in our way, as stum¬
bling-blocks in the pursuit of truth; and it is
only to be regretted on such occasions, for the
sake of his own happiness, that his genius and
temper qualified and disposed him more to start
the problem than to investigate the solution.
When Montaigne touches on religion, he is,
in general, less pleasing than on other subjects.
His constitutional temper, it is probable, pre¬
disposed him to scepticism; but this original
bias could not fail to be mightily strengthened
by the disputes, both religious and political,
which, during his lifetime, convulsed Europe,
and more particularly his own country. On a
mind like his it may be safely presumed, that
the writings of the Reformers, and the instruc¬
tions of Buchanan, were not altogether without
effect; and hence, in all probability, the per¬
petual struggle, which he is at no pains to con¬
ceal, between the creed of his infancy, and the
lights of his mature understanding. He speaks,
indeed, of ££ reposing tranquilly on the pillow of
doubtbut this language is neither reconcileable
with the general complexion of his works, nor
with the most authentic accounts we have re¬
ceived of his dying moments. It is a maxim of
his own, that, ££ in forming a judgment of a
man’s life, particular regard should be paid to
his behaviour at the end of itto which he
pathetically adds, ££ that the chief study of his
own life was, that his latter end might be de¬
cent, calm, and silent.” The fact is (if we may
credit the testimony of his biographers), that,
in his declining years, he exchanged his boast¬
ed pillow of doubt for the more powerful opiates
prescribed by the infallible church; and that he
1 Book i. chap. xxv.
2 Montaigne s education, however, had not been neglected by his father. On the contrary, he tells us himself, that
George Buchanan, the great poet of Scotland, and Marcus Antonius Muretus, the best orator of his time, were among
the number of his domestic preceptors.”—“ Buchanan,” he adds, “ when I saw him afterwards in the retinue of the late
Mareschal de Brissac, told me, that he was about to write a treatise on the education of children, and that he would take
the model of it from mine.”—Book i. chap. xxv.
DISSERTATION FIRST.
51
expired in performing what his old preceptor
Buchanan would not have scrupled to describe
as an act of idolatry.1 2
The scepticism of Montaigne seems to have
been of a very peculiar cast, and to have had
little in common with that either of Bayle or of
Hume. The great aim of the two latter writers
evidently was, by exposing the uncertainty of
our reasonings whenever we pass the limit of
sensible objects, to inspire their readers with a
complete distrust of the human faculties on all
moral and metaphysical topics. Montaigne, on
the other hand, never thinks of forming a sect;
hut, yielding passively to the current of his re¬
flections and feelings, argues, at different times,
according to the varying state of his impressions
and temper, on opposite sides of the same ques¬
tion. On all occasions, he preserves an air of
the most perfect sincerity; and it was to this,
I presume, much more than to the superiority
of his reasoning powers, that Montesquieu al¬
luded, when he said, “ In the greater part of
authors I see the writer; in Montaigne I see
nothing hut the thinker.” The radical fault of
his understanding consisted in an incapacity of
forming, on disputable points, those decided and
fixed opinions which can alone impart either
force or consistency to intellectual character.
For remedying this weakness, the religious con¬
troversies, and the civil wars recently engender¬
ed by the Reformation, were but ill calculated.
The minds of the most serious men, all over
Christendom, must have been then unsettled in
an extraordinary degree; and where any pre¬
disposition to scepticism existed, every external
circumstance must have conspired to cherish and
confirm it. Of the extent to which it was car¬
ried, about the same period, in England, some
judgment may be formed from the following de¬
scription of a Sceptic by a winter not many years
posterior to Montaigne.
“ A sceptic in religion is one that hangs in
the balance with all sorts of opinions; whereof
not one but stirs him, and none sways him. A
man guiltier of credulity than he is taken to be;
for it is out of his belief of every thing that he
believes nothing. Each religion scares him
from its contrary, none persuades him to itself.
He would be wholly a Christian, but that he is
something of an Atheist; and wholly an Atheist,
but that he is partly a Christian; and a perfect
Heretic, but that there are so many to distract
him. He finds reason in all opinions, truth in
none; indeed, the least reason perplexes him,
and the best will not satisfy him. He finds
doubts and scruples better than resolves them,
and is ahvays too hard for himself”2 If this
portrait had been presented to Montaigne, I have
little doubt that he would have had the candour
to acknowledge, that he recognised in it some
of the most prominent and characteristical fea¬
tures of his own mind.3
The most elaborate, and seemingly the most
serious, of all Montaigne’s essays, is his long
and somewhat tedious Apology for Haimond de
Sebonde, contained in the twelfth chapter of his
second book. This author appears, from Mon¬
taigne’s account, to have been a Spaniard, who
professed physic at Thoulouse, towards the end
of the fourteentli century; and who published
a treatise, entitled, Theologia Naturalis, which
was put into the hands of Montaigne’s father by
a friend, as a useful antidote against the inno¬
vations with which Luther was then beginning
to disturb the ancient faith. That, in this parti¬
cular instance, the book answered the intended
purpose, may be presumed from the request of
old Montaigne to his son, a few days before his
1 “ Sentant sa fin approcher, il fit dire la messe dans sa chambre. A 1’eldvation de I’hostie, il se leva sur son lit pour
I’adorer; mais une foiblesse 1’enleva dans ce moment meme, le 15 Septembre 1592, a GO ans.”—Nouveau Diet. Histor. a.
Lyon, 1804, Art. Montaigne.
2 Micro-cosmography, or a Piece of the World Discovered, in Essays and Characters. For a short notice of the author of this
very curious book (Bishop Earle), See the edition published at London in 1811. The chapter containing the above passage
is entitled, A Sceptic in Religion ; and it has plainly suggested to Lord Clarendon some of the ideas, and even expressions,
which occur in his account of Chillingworth.
3 “ The writings of the best authors among the ancients,” Montaigne tells us on one occasion, “ being full and solid,
tempt and carry me which way almost they will. He that I am reading seems always to have the most force; and I find
that every one in turn has reason, though they contradict one another.”—Book ii. chap. xii.
52
PRELIMINARY DISSERTATIONS.
death, to translate it into French from the Spa¬
nish original. His request was accordingly-
complied with; and the translation is referred
to hy Montaigne in the first edition of his Essays,
printed at Bourdeaux in 1580; hut the execu¬
tion of this filial duty seems to have produced
on Montaigne’s own mind very different effects
from what his father had anticipated.1
The principal aim of Sehonde’s hook, accord¬
ing to Montaigne, is to show that “ Christians
are in the wrong to make human reasoning the
basis of their belief, since the object of it is only
conceived hy faith, and by a special inspiration
of the divine grace.” To this doctrine Mon¬
taigne professes to yield an implicit assent; and,
under the shelter of it, contrives to give free
vent to all the extravagances of scepticism. The
essential distinction between the reason of man,
and the instincts of the lower animals, is at
great length, and with no inconsiderable inge¬
nuity, disputed; the powers of the human un¬
derstanding, in all inquiries, whether physical
or moral, are held up to ridicule; an universal
Pyrrhonism is recommended; and we are again
and again reminded, that “ the senses are the be¬
ginning and the end of all our knowledge” Who¬
ever has the patience to peruse this chapter with
attention, will be surprised to find in it the ru¬
diments of a great part of the licentious philo¬
sophy of the eighteenth century; nor can he
fail to remark the address with which the author
avails himself of the language afterwards adopt¬
ed by Bayle, Helvetius, and Hume :—“ That,
to be a philosophical sceptic, is the first step to¬
wards becoming a sound believing Christian.”3
It is a melancholy fact in ecclesiastical history,
that this insidious maxim should have been
sanctioned, in our times, hy some theologians of
no common pretensions to orthodoxy; who, in
direct contradiction to the words of Scripture,
have ventured to assert, that “ he who comes
to God must first believe that he is not.” Is
it necessary to remind these grave retailers of
Bayle’s sly and ironical sophistry, that every
argument for Christianity, drawn from its in¬
ternal evidence, tacitly recognises the authority
of human reason; and assumes, as the ultimate
criteria of truth and of falsehood, of right and
of wrong, certain fundamental articles of belief,
discoverable hy the light of Nature ?5
Charron is well known as the chosen friend
of Montaigne’s latter years, and as the confi¬
dential depositary of his philosophical senti¬
ments. Endowed with talents far inferior in
force and originality to those of his master, he
possessed, nevertheless, a much sounder and
more regulated judgment; and as his reputation,
notwithstanding the liberality of some of his
peculiar tenets, was high among the most re¬
spectable and conscientious divines of his own
church, it is far from improbable, that Mon¬
taigne committed to him the guardianship of his
posthumous fame, from motives similar to those
which influenced Pope, in selecting Warburton
as his literary executor. The discharge of this
trust, however, seems to have done less good to
Montaigne than harm to Charron; for while the
unlimited scepticism, and the indecent levities
The very few particulars known with respect to Sebonde have been collected by Bayle.—See his Dictionary, Art.
Sebonde.
* This expression is Mr Hume’s ; but the same proposition, in substance, is frequently repeated by the two other
writers, and is very fully enlarged upon by Bayle in the Illustration upon the Sceptics, annexed to his Dictionary.
* “ I once asked Adrian Turnelus," says Montaigne, “ what he thought of Sebonde’s treatise. The answer he made to
me was, That he believed it to be some extract from Thomas Aquinas, for that none but a genius like his was capable of
such ideas.”
I must not, however, omit to mention, that a very learned Protestant, Hugo Grotius, has expressed himself to his friend
Bignon not unfavourably of Sebonde’s intentions, although the terms in which he speaks of him are somewhat equivocal,
and imply but little satisfaction with the execution of his design. “ Non ignoras quantum excoluerint istam materiam
(argumentum soil, pro Religione Christiana) philosophica sultilitate Raimundus Sebundus, dialogorum varietate Ludovicus
Vives, maxima autem turn eruditione turn facundia vestras Philippus Mornaeus.” The authors of the Nouveau Dictionnaire
Historique (Lyons, 1804) have entered much more completely into the spirit and drift of Sebonde’s reasoning, when they
observe, “ Ce livre offre des singularites hardies, qui plurent dans le temps aux philosophes de ce siecle, et qui ne deplairoicnt
pas a ceux du noire."
It is proper to add, that I am acquainted with Sebonde only through the medium of Montaigne’s version, which does not
lay claim to the merit of strict fidelity; the translator himself having acknowledged, that he had given to the Spanish phi¬
losopher tk un accoutrement k la Franchise, et qu’il 1’a devetu de son port farouche et maintien barbaresque, de maniere
qu’il a mes-hui assez de facjon pour se presenter en toute bonne compagnie.”
DISSERTATION FIRST.
53
of the former, were viewed by the zealots of
those days with a smile of tenderness and indul¬
gence, the slighter heresies of the latter were
marked with a severity the more rigorous and
unrelenting, that, in points of essential import¬
ance, they deviated so very little from the stand¬
ard of the Catholic faith. It is not easy to
guess the motives of this inconsistency; but
such we find from the fact to have been the
temper of religious bigotry, or, to speak more
correctly, of political religionism in all ages of
the world.1
As an example of Charron’s solicitude to pro¬
vide an antidote against the more pernicious er¬
rors of his friend, I shall only mention his inge¬
nious and philosophical attempt to reconcile,
with the moral constitution of human nature,
the apparent discordancy in the judgments of
different nations concerning right and wrong.
His argument on this point is in substance the
very same with that so well urged by Beattie,
in opposition to Locke’s reasonings against the
existence of innate practical principles. It is
difficult to say, whether, in this instance, the
coincidence between Montaigne and Locke, or
that between Charron and Beattie, be the more
remarkable.2 3
Although Charron has affected to give to his
work a systematical form, by dividing and sub¬
dividing it into books and chapters, it is in re¬
ality little more than an unconnected series of
essays on various topics, more or less distantly
related to the science of Ethics. On the powers
of the understanding he has touched but slight¬
ly ; nor has he imitated Montaigne, in anato¬
mizing, for the edification of the world, the pe¬
culiarities of his own moral character. It has
probably been owing to the desultory and po¬
pular style of composition common to both, that
so little attention has been paid to either by
those who have treated of the history of French
philosophy. To Montaigne’s merits, indeed, as
a lively and amusing essayist, ample justice has
been done; but his influence on the subsequent
habits of thinking among his countrymen re¬
mains still to be illustrated. He has done more,
perhaps, than any other author (I am inclined
to think with the most honest intentions), to in¬
troduce into men's houses (if I may borrow an
expression of Cicero) what is now called the
new philosophy,—a philosophy certainly very
different from that of Socrates. In the fashion¬
able world, he has, for more than two centuries,
maintained his place as the first of moralists; a
circumstance easily accounted for, when we at¬
tend to the singular combination, exhibited in
his writings, of a semblance of erudition, with
what Malebranche happily calls his air du
monde, and air cavalier.'5 As for the graver and
less attractive Charron, his name would pro¬
bably before now have sunk into oblivion, had
it not been so closely associated, by the acci¬
dental events of his life, with the more cele¬
brated name of Montaigne.4
1 Montaigne, cet auteur charmant,
Tour-a-tour profond et frivole,
Dans son chateau paisiblement,
Loin de tout frondeur malevole,
Doutoit de tout impunement,
Et se moquoit tres librement
Des bavards fourrds de 1’e'cole.
Mais quand son eleve Charron,
Plus retenu, plus mdthodique,
De sagesse donna le^on,
II fut pres de perir, dit-on,
Par la haine theologique.
Voltaire, Epitre au President Hinault. .
* See Beattie’s Essay on Fable and Romance ; and Charron de la Sagesse, Liv. ii. c. 8. It may amuse the curious reader
also to compare the theoretical reasonings of Charron with a memoir in'the Phil. Trans, for 1773, by Sir Roger Curtis,
containing some particulars with respect to the country of Labrador.
3 “ Ah I’aimable homme, qu'il est de bonne compagnie ! C’est mon ancien ami; mais, h force d’etre ancien, il m’est nou¬
veau.”—Madame de SEVI&^^E,.
* Montaigne himself seems, from the general strain of his writings, to have had but little expectation of the posthumous
fame which he has so long continued to enjoy. One of his reflections on this head is so characteristical of the author as a
man, and, at the same time, affords so fine a specimen of the graphical powers of his now antiquated style, that I am tempted
to transcribe it in his own words : “ J’ecris mon livre k peu d’hommes et a peu d’anne'es ; s’il q’eut ete une matiere de
duree, il 1’eut fallu commettre k un langage plus ferme. Selon la variation continuelle qui a suivi le notre jusqu’k cette
54
PRELIMINARY DISSERTATIONS.
The preceding remarks lead me, by a natural
connection of ideas (to which I am here much
more inclined to attend than to the order of
dates), to another writer of the seventeenth cen¬
tury, whose influence over the literary and phi¬
losophical taste of France has been far greater
than seems to be commonly imagined. I allude
to the Duke of La Rochefoucauld, author of the
Maxims and Moral Reflections.
Voltaire was, I believe, the first who ventur¬
ed to assign to La Rochefoucauld the pre-emi¬
nent rank which belongs to him among the French
classics. u One of the works,” says he, “ which
contributed most to form the taste of the nation
to a justness and precision of thought and ex¬
pression, was the small collection of maxims by
Francis Duke of La Rochefoucauld. Although
there he little more than one idea in the hook,
that self-love is the spring of all our actions, yet
this idea is presented in so great a variety of
forms, as to he always amusing. When it first
appeared, it was read with avidity; and it con¬
tributed, more than any other performance, since
the revival of letters, to improve the vivacity,
correctness, and delicacy of French composition.”
Another very eminent judge of literary merit
(the late Dr Johnson) was accustomed to say
of La Rochefoucauld’s Maxims, that it was al¬
most the only hook written by a man of fashion,
of which professed authors had reason to he jea¬
lous. Nor is this wonderful, when we consider
the unwearied industry of the very accomplish¬
ed writer, in giving to every part of it the high¬
est and most finished polish which his exquisite
taste could bestow. When he had committed a
maxim to paper, he was in use to circulate it
among his friends, that he might avail himself
of their critical animadversions; and, if we may
credit Segrais, altered some of them no less than
thirty times, before venturing to submit them to
the public eye.
That the tendency of these maxims is, upon
the whole, unfavourable to morality, and that
they always leave a disagreeable impression on
the mind, must, I think, he granted. At the
same time, it may he fairly questioned, if the
motives of the author have in general been well
understood, either by his admirers or his oppo¬
nents. In affirming that self-love is the spring
of all our actions, there is no good reason for
supposing that he meant to deny the reality of
moral distinctions as a philosophical truth;—a
supposition quite inconsistent with his own fine
and deep remark, that hypocrisy is itself an ho¬
mage which vice renders to virtue. He states it
merely as a position which, in the course of his
experience as a man of the world, he had found
very generally verified in the higher classes of
society, and which he was induced to announce
without any qualification or restriction, in order
to give more force and poignancy to his satire
In adopting this mode of writing, he has un¬
consciously conformed himself, like many other
French authors, who have since followed his
example, to a suggestion which Aristotle has
stated with admirable depth and acuteness in
his Rhetoric. “ Sentences or apophthegms lend
much aid to eloquence. One reason of this is,
that they flatter the pride of the hearers, who
are delighted when the speaker, making use of
general language, touches upon opinions which
they had before known to be true in part. Thus,
a person who had the misfortune to live in a bad
neighbourhood, or to have worthless children,
would easily assent to the speaker who should
affirm, that nothing is more vexatious than to
have any neighbours; nothing more irrational
than to bring children into the world.”1 This
observation of Aristotle, while it goes far to ac¬
count for the imposing and dazzling effect of
these rhetorical exaggerations, ought to guard us
against the common and popular error of mis-
heure, qux peut esperer que sa forme presente soit en usage d’ici a cinquante ans ? il ecoule tous les jours de nos mains, et
depuis que je vis s est altere de moitie. Nous disons qu’il est a cette heure parfait: Autant en dit du sien chaque siecle.
C est anx oons et utiles ecrits de le clouer a eux, et ira sa fortune selon le credit de notre etat."
How completely have both the predictions in the last sentence been verified by the subsequent history of the French
language!
, h (’yvupiai) ray; Xayay; fiorjuav fttya.Xnr, ftixy fuy om r»jv Qo^nKornra, rus ux^ouruv' %ulgt>vffi yaj, lav r/; Jta.Ho'kov Xiyuv,
Tf“ txetni Ttctra, tfcoviri. H fitv yap yvcofAV, llgnrui, xudoXov hrn' pstii^ovtri at xctHoXou Xtyofiivov,
a satr* ^a; ^ayaraXa^aavavrs; rvy^ovre cloh u r,s yi/rar; ry^fi aas^Wva; »j rl*va/; (puvXon, urohfar a* rev uVavra;, aySiv yurcyia,
■^uXitan^o))' ?), on ovoiv wXitJiangov riuvovoiu;.—Arist. Rhet. Lib. il. c. xxi.
The whole chapter is interesting and instructive, and shows how profoundly Aristotle had meditated the principles of
the rhetorical art. 1 1
DISSERTATION FIRST. 55
taking them for the serious and profound genera¬
lisations of science. As for La Rochefoucauld,
we know, from the best authorities, that, in pri¬
vate life, he was a conspicuous example of all
those moral qualities of which he seemed to deny
the existence; and that he exhibited, in this
respect, a striking contrast to the Cardinal de
Retz, who has presumed to censure him for his
want of faith in the reality of virtue.
In reading La Rochefoucauld, it should ne¬
ver be forgotten, that it was within the vortex
of a court he enjoyed his chief opportunities of
studying the world; and that the narrow and
exclusive circle in which he moved was not
likely to afford him the most favourable speci¬
mens of human nature in general. Of the
Court of Lewis XIV. in particular, we are told
by a very nice and reflecting observer (Madame
de la Fayette), that C£ ambition and gallantry
were the soul, actuating alike both men and wo¬
men. So many contending interests, so many
different cabals were constantly at work, and in
all of these, women bore so important a part,
that love was always mingled with business, and
business with love. Nobody was tranquil or in¬
different. Every one studied to advance him¬
self by pleasing, serving, or ruining others. Idle¬
ness and languor were unknown, and nothing
was thought of but intrigues or pleasures.”
In the passage already quoted from Voltaire,
he takes notice of the effect of La Rochefou¬
cauld’s Maxims, in improving the style of French
composition. We may add to this remark, that
their effect has not been less sensible in vitiating
the tone and character of French philosophy, by
bringing into vogue those false and degrading
representations of human nature and of human
life, which have prevailed in that country, more
or less, for a century past. Mr Addison, in
one of the papers of the Taller, expresses his in¬
dignation at this general bias among the French
writers of his age. “ It is impossible,” he ob¬
serves, “ to read a passage in Plato or Tully,
and a thousand other ancient moralists, without
being a greater and better man for it. On the
contrary, I could never read any of our modish
French authors, or those of our own country,
who are the imitators and admirers of that nation,
without being, for some time, out of humour
with myself, and at everything about me. Their
business is to depreciate human nature, and to
consider it under the worst appearances; they
give mean interpretations and base motives to
the worthiest actions. In short, they endeavour
to make no distinction between man and man,
or between the species of man and that of the
brutes.”1
It is very remarkable, that the censure here
bestowed by Addison on the fashionable French
wits of his time should be so strictly applicable
to Helvetius, and to many others of the most
admired authors whom France has produced in
our own day. It is still more remarkable to find
the same depressing spirit shedding its malig¬
nant influence on French literature, as early as
the time of La Rochefoucauld, and even of Mon¬
taigne ; and to observe how very little has been
done by the successors of these old writers, but
to expand into grave philosophical systems their
loose and lively paradoxes; disguising and for¬
tifying them by the aid of those logical princi¬
ples, to which the name and authority of Locke
have given so wide a circulation in Europe.
In tracing the origin of that false philosophy
on which the excesses of the French revolu¬
tionists have entailed such merited disgrace, it is
usual to remount no higher than to the profli¬
gate period of the Regency; but the seeds of its
most exceptionable doctrines had been sown in
that country at an earlier era, and were indebt¬
ed for the luxuriancy of their harvest, much
more to the political and religious soil where
they struck their roots, than to the skill or fore¬
sight of the individuals by whose hands they
were scattered.
I have united the names of Montaigne and of
La Rochefoucauld, because I consider their
writings as rather addressed to the world at
large, than to the small and select class of spe¬
culative students. Neither of them can be said
to have enriched the stock of human knowledge
by the addition of any one important general
1 Tatler, No. 103. The last paper of the Tatler was published in 1711 ; and, consequently, the above passage must be
understood as referring to the modish tone of French philosophy prior to the death of Louis XIV.
56
PRELIMINARY DISSERTATIONS.
conclusion; but the maxims of both have oper
rated very extensively and powerfully on the
taste and principles of the higher orders all over
Europe, and predisposed them to give a welcome
reception to the same ideas, when afterwards
reproduced with the imposing appendage of lo¬
gical method, and of a technical phraseology.
The foregoing reflections, therefore, are not so
foreign as might at first be apprehended, to the
subsequent history of ethical and of metaphysi¬
cal speculation. It is time, however, now to
turn our attention to a subject far more inti¬
mately connected with the general progress of
human reason,—the philosophy of Descartes,
DESCARTES—GASSENDI—MALEBRANGHE.
According to a late writer,1 whose literary
decisions (excepting where he touches on reli¬
gion or politics) are justly entitled to the high¬
est deference, Descartes has a better claim than
any other individual, to be regarded as the fa¬
ther of that spirit of free inquiry, which in mo¬
dern Europe has so remarkably displayed itself
in all the various departments of knowledge.
Of Bacon, he observes, “ that though he pos¬
sessed, in a most eminent degree, the genius of
philosophy, he did not unite with it the genius
of the sciences; and that the methods proposed
by him for the investigation of truth, consisting
entirely of precepts which he was unable to ex¬
emplify, had little or no effect in accelerating
the rate of discovery.” As for Galileo, he re¬
marks, on the other hand, ii that his exclu¬
sive taste for mathematical and physical re¬
searches, disqualified him for communicating to
the general mind that impulse of which it stood
in need.”
“ This honour,” he adds, “ was reserved for
Descartes, who combined in himself the cha-
racteristical endowments of both his predecessors.
If, in the physical sciences, his march be less
sure than that of Galileo—if his logic be less
cautious than that of Bacon—yet the very te¬
merity of his errors was instrumental to the
progress of the human race. He gave activity
to minds which the circumspection of his rivals
could not awake from their lethargy. He call¬
ed upon men to throw off the yoke of authority,
acknowledging no influence but what reason
should avow: And his call was obeyed by a
multitude of followers, encouraged by the bold¬
ness, and fascinated by the enthusiasm of their
leader.”
In these observations, the ingenious author has
rashly generalised a conclusion deduced from
the literary history of his own country. That
the works of Bacon were but little read there till
after the publication of D’Alembert’s Preliminary
Discourse, is, I believe, an unquestionable fact;8
not that it necessarily follows from this, that, even
in France, no previous effect had been produced
by the labours of Boyle, of Newton, and of the
other English experimentalists, trained in Bacon’s
school. With respect to England, it is a fact not
less certain, that at no period did the philosophy of
Descartes produce such an impression on public
opinion, either in Physics or in Ethics, as to
give the slightest colour to the supposition, that it
contributed, in the most distant degree, to the
subsequent advances made by our countrymen
in these sciences. In Logic and Metaphysics,
indeed, the case was different. Here the writings
of Descartes did much; and if they had been
studied with proper attention, they might have
done much more. But of this part of their me¬
rits, Condorcet seems to have had no idea. His
eulogy, therefore, is rather misplaced than ex¬
cessive. He has extolled Descartes as the father
of Experimental Physics: He would have been
nearer the truth, if he had pointed him out as
the father of the Experimental Philosophy of
the Human Mind.
In bestowing this title on Descartes, I am far
from being inclined to compare him, in the nura-
4 ^onaorceu ^ f i
2 One reason for this is well pointed out by D’Alembert. 44II n’y a que les chefs de secte en tout genre, dont e?s
ouvrages puissent avoir un certain eclat; Bacon n’a pas dte du nombre, et la forme de sa philosophie s’y opposoit: el e
dtoit trop sage pour e'tonner personne.”—Disc- Prd.
DISSERTATION FIRST.
57
ber or importance of the facts which he has re¬
marked concerning our intellectual powers, to
various other writers of an earlier date. I al¬
lude merely to his clear and precise conception
of that operation of the understanding (distin¬
guished afterwards in Locke’s Essay by the name
of Reflection), through the medium of which all
our knowledge of Mind is exclusively to be ob¬
tained. Of the essential subserviency of this
power to every satisfactory conclusion that can
be formed with respect to the mental phenome¬
na, and of the futility of every theory which
would attempt to explain them by metaphors
borrowed from the material world, no other phi¬
losopher prior to Locke seems to have been ful¬
ly aware ; and from the moment that these truths
were recognised as logical principles in the study
of mind, a new era commences in the history of
that branch of science. It will be necessary,
therefore, to allot to the illustration of this part
of the Cartesian philosophy a larger space than
the limits of my undertaking will permit me
to afford to the researches of some succeeding
inquirers, who may, at first sight, appear more
worthy of attention in the present times.
It has been repeatedly asserted by the Ma¬
terialists of the last ^entury, that Descartes was
the first Metaphysician by whom the pure im¬
materiality of the human soul was taught; and
that the ancient philosophers, as well as the
schoolmen, went no farther than to consider
mind as the result of a material organisation, in
which the constituent elements approached to
evanescence in point of subtlety. Both of
these propositions I conceive to be totally un¬
founded. That many of the schoolmen, and
that the wisest of the ancient philosophers, when
they described the mind as a spirit, or as a spark
of celestial fire, employed these expressions, not
with any intention to materialise its essence, but
merely from want of more unexceptionable lan¬
guage, might be shown with demonstrative evi¬
dence, if this were the proper place for entering
into the discussion. But what is of more im¬
portance to be attended to, on the present oc¬
casion, is the effect of Descartes’ writings in dis¬
entangling the logical principle above mentioned,
from the scholastic question about the nature of
mind, as contradistinguished from matter. It
were indeed to be wished, that he had perceiv¬
ed still more clearly and steadily the essential
importance of keeping this distinction constant¬
ly in view ; but he had at least the merit of il¬
lustrating, by his own example, in a far greater
degree than any of his predecessors, the possi¬
bility of studying the mental phenomena, with¬
out reference to any facts but those Avhich rest
on the evidence of consciousness. The meta¬
physical question about the nature of mind he
seems to have considered as a problem, the so¬
lution of which was an easy corollary from these
facts, if distinctly apprehended; but still as a
problem, whereof it was possible that different
views might be taken by those who agreed in
opinion, as far as facts alone were concerned.
Of this a very remarkable example has since oc¬
curred in the case of Mr Locke, who, although
he has been at great pains to show, that the
power of refection bears the same relation to the
study of the mental phenomena, which the power
of observation bears to the study of the material
world, appears, nevertheless, to have been far
less decided than Descartes with respect to the
essential distinction between Mind and Matter ;
and has even gone so far as to hazard the un¬
guarded proposition, that there is no absurdity
in supposing the Deity to have superadded to
the other qualities of matter the power of thinking.
His scepticism, however, on this point, did not
prevent his good sense from perceiving, with the
most complete conviction, the indispensable ne¬
cessity of abstracting from the analogy of mat¬
ter, in studying the laws of our intellectual frame.
The question about the nature or essence of
the soul, has been, in all ages, a favourite sub¬
ject of discussion among Metaphysicians, from
its supposed connection with the argument in
proof of its immortality. In this light it has
plainly been considered by both parties in the
dispute; the one conceiving, that if Mind could
be shown to have no quality in common with
Matter, its dissolution was physically impossible;
the other, that if this assumption could be dis¬
proved, it would necessarily follow, that the whole
man must perish at death. For the last of these
opinions Dr Priestley and many other specula¬
tive theologians have of late very zealously con¬
tended ; flattering themselves, no doubt, with
H
DISS. I. PART i.
58
PRELIMINARY DISSERTATIONS.
the idea, that they were thus preparing a triumph
for their own peculiar schemes of Christianity.
Neglecting, accordingly, all the presumptions
for a future state, afforded by a comparison of
the course of human affairs with the moral judg¬
ments and moral feelings of the human heart;
and overlooking, with the same disdain, the
presumptions arising from the narrow sphere of
human knowledge, when compared with the in¬
definite improvement of which our intellectual
powers seem to be susceptible, this acute but
superficial writer attached himself exclusively
to the old and hackneyed pneumatological argu¬
ment ; tacitly assuming as a principle, that the
future prospects of man depend entirely on the
determination of a physical problem, analogous
to that which was then dividing chemists about
the existence or non-existence of Phlogiston.
In the actual state of science, these speculations
might well have been spared. Where is the
sober metaphysician to be found, who now
speaks of the immortality of the soul as a logi¬
cal consequence of its immateriality; instead of
considering it as depending on the will of that
Being by whom it was at first called into exist¬
ence ? And, on the other hand, is it not uni¬
versally admitted by the best philosophers, that
whatever hopes the light of nature encourages
beyond the present scene, rest solely (like all
our other anticipations of future events) on the
general tenor and analogy of the laws by which
we perceive the universe to he governed ? The
proper use of the argument concerning the im¬
materiality of mind, is not to establish any posi¬
tive conclusion as to its destiny hereafter ; hut
to repel the reasonings alleged by materialists,
as proofs that its annihilation must he the ob¬
vious and necessary effect of the dissolution of
the body.1
I thought it proper to state this consideration
pretty fully, lest it should be supposed that the
logical method recommended by Descartes for
studying the phenomena of mind, has any ne¬
cessary dependence on his metaphysical opinion
concerning its being and properties, as a separate
substance.2 3 Between these two parts of his
system, however, there is, if not a demonstrative
connection, at least a natural and manifest af¬
finity ; inasmuch as a steady adherence to his
logical method (or, in other words, the habitual
exercise of patient refection), by accustoming
us to break asunder the obstinate associations
to which materialism is indebted for the early
hold it is apt to take of the fancy, gradually and
insensibly predisposes us in favour of his me¬
taphysical conclusion. It is to be regretted,
that, in stating this conclusion, his commentators
should so frequently make use of the word spiri¬
tuality ; for which I do not recollect that his
own works afford any authority. The proper
expression is immateriality, conveying merely a
negative idea; and, of consequence, implying
nothing more than a rejection of that hypothesis
concerning the nature of M(pd, which the scheme
of materialism so gratuitously, yet so dogmati¬
cally assumes.5
The power of Reflection, it is well known, is
the last of our intellectual faculties that unfolds
itself; and, in by far the greater number of in¬
dividuals, it never unfolds itself in any consider¬
able degree. It is a fact equally certain, that,
long before the period of life when this power
begins to exercise its appropriate functions, the
understanding is already preoccupied with a
1 “ We shall here be content,” says the learned John Smith of Cambridge, “with that sober thesis of Plato, in his
Timasus, who attributes the perpetuation of all substances to the benignity and liberality of the Creator; whom he there¬
fore brings in thus speaking, vpik; ix. a6a.va.roi ovSi uXuroi, x. r. X. You are not of yourselves immortal nor indissoluble, but would
relapse and slide back from that being which I have given you, should I withdraw the influence of my own power from you ;
but yet you shall hold your immortality by a patent from myself." (Select Discourses, Cambridge, 1660.) I quote this pas¬
sage from one of the oldest partisans of Descartes among the English philosophers.
Descartes himself is said to have been of a different opinion. " “ On a e'te etonne,” says Thomas, “ que dans ses Medi¬
tations Metaphysiques, Descartes n’ait point parle de 1’immortalite de fame. Mais il nous apprend lui-memepar une de ses
lettres, qu’ayant e'tabli clairement, dans cet ouvrage, la distinction de fame et de la matiere, il suivoit ne'cessairement de
cette distinction, que fame par sa nature ne pouvoit perir avec le corps.”—Eloge de Descartes. Note 21.
2 I employ the scholastic word substance, in conformity to the phraseology of Descartes; but I am fully aware of the
strong objections to which it is liable, not only as a wide deviation from popular use, which has appropriated it to things
material and tangible, but as implying a greater degree of positive knowledge concerning the nature of mind, than our fa¬
culties are fitted to attain—For some further remarks on this point, See Note I.
3 See Note K.
DISSERTATION FIRST.
59
chaos of opinions, notions, impressions, and as¬
sociations, bearing on the most important ob¬
jects of human inquiry; not to mention the in¬
numerable sources of illusion and error con¬
nected with the use of a vernacular language,
learned in infancy by rote, and identified with
the first processes of thought and perception.
The consequence is, that when man begins to
reflect, he finds himself (if I may borrow an
allusion of M. Turgot’s) lost in a labyrinth, in¬
to which he had been led blindfold.1 2 3 To the
same purpose, it was long ago complained of by
Bacon, <{ that no one has yet been found of so
constant and severe a mind, as to have de¬
termined and tasked himself utterly to abolish
theories and common notions, and to apply his
intellect, altogether smooth and even, to par¬
ticulars anew. Accordingly, that human reason
which we have, is a kind of medley and unsorted
collection, from much trust and much accident,
and the childish notions which we first drank
in. Whereas, if one of ripe age and sound
senses, and a mind thoroughly cleared, should
apply himself freshly to experiment and par¬
ticulars, of him were better things to he hoped.”
What Bacon has here recommended, Des¬
cartes attempted to execute; and so exact is the
coincidence of his views on this fundamental
point with those of his predecessor, that it is with
difficulty I can persuade myself that he had
never read Bacon’s works. * In the prosecution
of this undertaking, the first steps of Descartes
are peculiarly interesting and instructive; and
it is these alone which merit our attention at
present. As for the details of his system, they
are now curious only as exhibiting an amusing
contrast to the extreme rigour of the principle
from which the author sets out; a contrast so
very striking, as fully to justify the epigram¬
matic saying of D’Alembert, that “ Descartes
began with doubting of every thing, and ended
in believing that he had left nothing unexplained.”
Among the various articles of common belief
which Descartes proposed t#subject to a severe
scrutiny, he enumerates particularly, the con¬
clusiveness of mathematical demonstration; the
existence of God; the existence of the material
world; and even the existence of his own body.
The only thing that appeared to him certain and
incontrovertible, was his own existence; by
which he repeatedly reminds us, we are to un¬
derstand merely the existence of his mind, ab¬
stracted from all consideration of the material
organs connected with it. About every other
proposition, he conceived, that doubts might
reasonably be entertained; but to suppose the
non-existence of that which thinks, at the very
moment it is conscious of thinking, appeared to
him a contradiction in terms. From this single
postulatum, accordingly, he took his departure ;
resolved to admit nothing as a philosophical
truth, which could not be deduced from it by a
chain of logical reasoning.5
Having first satisfied himself of his own ex¬
istence, his next step was to inquire, how far
his perceptive and intellectual faculties were en¬
titled to credit. For this purpose, he begins
with offering a proof of the existence and at¬
tributes of God;—truths which he conceived to
be necessarily involved in the idea he was able
to form of a perfect, self-existent, and eternal
being. His reasonings on this point it would
be useless to state. It is sufficient to observe,
that they led him to conclude, that God cannot
possibly be supposed to deceive his creatures ;
and therefore, that the intimations of our senses,
and the decisions of our reason, are to be trusted
to with entire confidence, wherever they afford
us clear and distinct ideas of their respective ob¬
jects.4
1 “ Quand rhomme a voulu se replier sur lui-meme, il s’est trouve dans un labyrinthe, oii il dtoit entrd les yeux
bandds.”—CEuvres ds Turgot, Tom. II. p. 261.
2 See Note L.
3 “ Sic autem rejicientes ilia omnia, de quibus aliquo modo possumus dubitare, ac etiam falsa esse fingentes, facile quidem
supponimus nullum esse Deum, nullum ccelum, nulla corpora; nosque etiam ipsos, non habere manus, nec pedes, nec
denique ullum corpus : non autem ideo nos qui talia cogitamus nihil esse: repugnat enim, ut putemus id quod cogitat, eo
ipso tempore quo cogitat, non existere. Ac proinde baec cognitio, ego cogito, ergo sum, est omnium prima et certissima,
qute cuilibet ordine philosophanti occurrat.”—Princip. Philos. Pars I. § 7-
* The substance of Descartes’ argument on these fundamental points, is thus briefly recapitulated by himself in the
conclusion of his third Meditation:—“ Dum in meipsum mentis aciem converto, non modo intelligo me esse rem in-
completam, et ab alio dependentem, remque ad majora et meliora indefinite aspirantem, sed simul etiam intelligo ilium, a
60
PRELIMINARY DISSERTATIONS.
As Descartes conceived the existence of God
(next to the existence of his own mind) to he
the most indisputable of all truths, and rested
his confidence in the conclusions of human rea¬
son entirely on his faith in the divine veracity,
it is not surprising that he should have rejected
the argument from final causes, as superfluous
and unsatisfactory. To have availed himself of
its assistance would not only have betrayed a
want of confidence in what he professed to re¬
gard as much more certain than any mathema¬
tical theorem; hut would obviously have ex¬
posed him to the charge of first appealing to
the divine attributes in proof of the authority
of his faculties; and afterwards, of appealing
to these faculties, in proof of the existence of
God.
It is wonderful that it should have escaped
the penetration of this most acute thinker, that
a vicious circle of the same description is involved
in every appeal to the intellectual powers, in
proof of their own credibility ; and that unless
this credibility he assumed as unquestionable, the
farther exercise of human reason is altogether
nugatory. The evidence for the existence of
God seems to have appeared to Descartes too
irresistible and overwhelming, to be subjected
to those logical canons which apply to all the
other conclusions of the understanding.1
Extravagant and hopeless as these prelimi¬
nary steps must now appear, they had never¬
theless an obvious tendency to direct the atten¬
tion of the author, in a singular degree, to the
phenomena of thought; and to train him to
those habits of abstraction from external objects,
which, to the hulk of mankind, are next to im¬
possible. In this way he was led to perceive,
with the evidence of consciousness, that the at¬
tributes of Mind were still more clearly and
distinctly knowahle than those of Matter; and
that, in studying the former, so far from at¬
tempting to explain them by analogies borrowed
from the latter, our chief aim ought to he, to
banish as much as possible from the fancy every
analogy, and even every analogical expression,
which, by inviting the attention abroad, might
divert it from its proper business at home. In
one word, that the only right method of philo¬
sophising on this subject was comprised in the
old stoical precept (understood in a sense some¬
what different from that originally annexed to
it) nec te qucesiveris extra. A just conception of
this rule, and a steady adherence to its spirit,
constitutes the ground-work of what is properly
called the Experimental Philosophy of the Hu¬
man Mind. It is thus that all our facts relating
to Mind must he ascertained; and it is only
upon facts thus attested by our own conscious¬
ness, that any just theory of Mind can he •
reared.
Agreeably to these views, Descartes was, I
think, the first who clearly saw that our idea of
Mind is not direct, hut relative;—relative to the
various operations of which we are conscious.
What am I ? he asks, in his second Meditation :
A thinking being,—that is, a being doubting,
quo pendeo, majora ista omnia non indefinite et potentia tantum, sed reipsa infinite in se habere, atque ita Deum esse;
totaque vis argumenti in eo est, quod agnoscam fieri non posse ut existam talis naturae qualis sum, nempe ideam Dei in
me habens, nisi revera Deus etiam existeret, Deus, inquam, file idem cujus idea in me est, hoc est, habens omnes illas
perfectiones quas ego non comprehendere, sed quocunque modo attingere cogitatione possum, et nullis plane defectibus
obnoxius. Ex his satis patet, ilium fallacem esse non posse : omnem enim fraudem et deceptionem a defectu aliquo pen-
dere lumine natural! manifestum est.”
The above argument for the existence of God (very improperly called by some foreigners an argument a priori), was
long considered by the most eminent men m Europe as quite demonstrative. For my own part, although I do not think
that it is by any means so level to the apprehension of common inquirers, as the argument from the marks of design every¬
where manifested in the universe, I am still less inclined to reject it as altogether unworthy of attention. It is far from
being so metaphysically abstruse as the reasonings of Newton and Clarke, founded on our conceptions of space and of time;
nor would it appear, perhaps, less logical and conclusive than that celebrated demonstration, if it were properly unfolded,
and stated in more simple and popular terms. The two arguments, however, are in no respect exclusive of each other;
and I have always thought, that, by combining them together, a proof of the point in question might be formed, more im¬
pressive and luminous than is to be obtained from either, when stated apart.
1 How painful is it to recollect, that the philosopher who had represented his faith in the veracity of God, as the sole
foundation of his confidence in the demonstrations of mathematics, was accused and persecuted by his contemporaries as an
atheist; and that, too, in the same country (Holland), where, for more than half a century after his death, his doctrines
were to be taught in all the universities with a blind idolatry ! A zeal without knowledge, and the influence of those earth¬
ly passions, from which even Protestant divines are not always exempted, may, it is to be hoped, go far to account for this
inconsistency and injustice, without adopting the uncharitable insinuation of D’Alembert: “ Malgre toute la sagacite qu’il
avoit employee pour nrouver 1’existence de Dieu, il fut accuse de la nier par des mimstres, qui peut-ctre ne la croyoient pas."
DISSERTATION FIRST.
61
knowing, affirming, denying, consenting, refu¬
sing, susceptible of pleasure and of pain.1 Of
all these things I might have had complete ex¬
perience, without any previous acquaintance
with the qualities and laws of matter; and
therefore it is impossible that the study of mat¬
ter can avail me aught in the study of my¬
self. This, accordingly, Descartes laid down
as a first principle, that nothing comprehensible
by the imagination can be at all subservient to the
knowledge of Mind ; and that the sensible images
involved in all our common forms of speaking
concerning its operations, are to he guarded
against with the most anxious care, as tending
to confound, in our apprehensions, two classes
of phenomena, which it is of the last importance
to distinguish accurately from each other.2
To those who are familiarly acquainted with
the writings of Locke, and of the very few
among his successors who have thoroughly en¬
tered into the spirit of his philosophy, the fore¬
going observations may not appear to possess
much either of originality or of importance; hut
when first given to the world, they formed the
greatest step ever made in the science of Mind, by
a single individual. What a contrast do they ex¬
hibit, not only to the discussions of the school¬
men, but to the analogical theories of Hobbes
at the very same periotf! and how often have
they been since lost sight of, notwithstanding
the clearest speculative conviction of their truth
and importance, by Locke himself, and by the
greatest part of his professed followers ! Had
they been duly studied and understood by Mr
Horne Tooke, they would have furnished him
with a key for solving those etymological riddles,
which, although mistaken by many of his con¬
temporaries for profound philosophical discove¬
ries, derive, in fact, the whole of their mystery,
from the strong bias of shallow reasoners to re¬
lapse into the same scholastic errors, from which
Descartes, Locke, Berkeley, Hume, and Reid,
have so successfully laboured to emancipate the
mind.
If any thing can add to our admiration of a
train of thought manifesting in its author so un¬
exampled a triumph over the strongest prejudices
of sense, it is the extraordinary circumstance of
its having first occurred to a young man, who
had spent the years commonly devoted to aca¬
demical study, amid the dissipation and tumult
of camps.3 Nothing could make this conceiv¬
able, but the very liberal education which he
had previously received under the Jesuits, at the
college of La I'leche f where, we are told, that
while yet a hoy, he was so distinguished by
.U j^°n sum comPages membrorum, quae corpus humanum appellatur; non sum etiam tenuis aliquis aer istis mem-
bns inrusus ; non ventus, non ignis, non vapor, non halitus Quid igitur sum ? res cogitans ; quid est hoc ? nempe du-
bitans, intelligens, affirmans, negans, volens, nolens,” &c Med. Sec.
“ Itaque cognosco, nihil eorum quae possum Imaginatione comprehendere, ad hanc quam de me habeo notitiam perti-
nere ; mentemque ab illis diligentissime esse avocandam, ut suam ipsa naturam quam distinctissime percipiat.—Ibid. A
tew sentences before, Descartes explains with precision in what sense Imagination is here to be understood. “ Nihil aliud
est imaginari quam rei corporeae figuram seu imaginem contemplari.”
following extracts from a book published at Cambridge in 1660 (precisely ten years after the death of Descartes),
while they furnish a useful comment on some of the above remarks, may serve to show, how completely the spirit of the
Cartesian philosophy of Mind had been seized even then, by some of the members of that university.
1 he souls of men exercising themselves first of all xivtnru Tgefianxip, as the Greek philosopher expresseth himself, merely
by a progressive kind of motion, spending themselves about bodily and material acts, and conversing only with sensible things;
they are apt to acquire such deep stamps of material phantasms to themselves, that they cannot imagine their own Being
to be any other than material and divisible, though of a fine ethereal nature. It is not possible for us well to know what our
souls are, but only by their xlvwru; xvxXixat, their circular or reflex motions, and converse with themselves, which can only
steal from them their own secrets.”—Smith's Select Discourses, p. 65, 66.
If we reflect but upon our own souls, how manifestly do the notions of reason, freedom, perception, and the like, offer
themselves to us, whereby we may know a thousand times more distinctly what our souls are than what our bodies are. For
the former, we know by an immediate converse with ourselves, and a distinct sense of their operations ; whereas all our
knowledge of the body is little better than merely historical, which we gather up by scraps and piecemeal, from more
doubtful and uncertain experiments which we make of them ; but the notions which we have of a mind, i. e. something
within us that thinks, apprehends, reasons, and discourses, are so clear and distinct from all those notions which we can
fasten upon a body, that we can easily conceive that if all body-being in the world were destroyed, yet we might then as
well subsist as now we do.”—Ibid. p. 98.
3 « Descartes porta les armes, d’abord en Hollande, sous le celebre Maurice de Nassau ; de-la en Allemagne, sous Maxi-
milien de Baviere, au commencement de la guerre de trente ans. II passa ensuite au service de I’Empereur Ferdinand II.
pour voir de plus pres les troubles de la Hongrie. On croit aussi, qu’au siege de la Rochelle, il combattit, comme volon-
taire, dans une bataille centre la flotte Angloise.”—Thomas, Eloge de Descartes, Note 8.
When Descartes quitted the profession of arms, he had arrived at the age of twenty-five.
4 It is a curious coincidence, that it was in the same village of La Fleche that Mr Hume fixed his residence, while com-
62
PRELIMINARY DISSERTATIONS.
habits of deep meditation, that he went among
his companions by the name ot the Philosopher.
Indeed, it is only at that early age, that such
habits are to be cultivated with complete suc¬
cess.
The glory, however, of having pointed out to
his successors the true method of studying the
theory of Mind, is almost all that can he claimed
by Descartes in logical and metaphysical science.
Many important hints, indeed, may be gleaned
from his works ; but, on the whole, he has added
very little to our knowledge of human nature.
Nor will this appear surprising, when it is re¬
collected, that he aspired to accomplish a simi¬
lar revolution in all the various departments of
physical knowledge;—not to mention the time
and thought he must have employed in those
mathematical researches, which, however lightly
esteemed by himself, have been long regarded
as the most solid basis of his fame.1
Among the principal articles of the Cartesian
philosophy, which are now incorporated with
our prevailing and most accredited doctrines,
the following seem to me to he chiefly entitled
to notice :
1. His luminous exposition of the common
logical error of attempting to define words
which express notions too simple to admit of
analysis. Mr Locke claims this improvement
as entirely his own; hut the merit of it un¬
questionably belongs to Descartes, although it
must he owned that he has not always sufficient¬
ly attended to it in his own researches.2
2. His observations on the different classes of
our prejudices—particularly on the errors to
which we are liable in consequence of a careless
use of language as the instrument of thought.
The greater part of these observations, if not
the whole, had been previously hinted at by
Bacon ; but they are expressed by Descartes
with greater precision and simplicity, and in a
style better adapted to the taste of the present
age.
3. The paramount and indisputable authority
which, in all our reasonings concerning the hu¬
man mind, he ascribes to the evidence of con¬
sciousness. Of this logical principle he has
availed himself, with irresistible force, in refu¬
ting the scholastic sophisms against the liberty
of human actions, drawn from the prescience of
the Deity, and other considerations of a theolo¬
gical nature.
4. The most important, however, of all his
improvements in metaphysics, is the distinction
which he has so clearly and so strongly drawn
between the primary and the secondary qualities
of matter. This distinction was not unknown
to some of the ancient schools of philosophy in
Greece ; but it was afterwards rejected by Aris¬
totle, and by the schoolmen; and it was reserv¬
ed for Descartes to place it in such a light, as
(with the exception of a very few sceptical or
rather paradoxical theorists) to unite the opi¬
nions of all succeeding inquirers. For this step,
so apparently easy, but so momentous in its con¬
sequences, Descartes was not indebted to any
long or difficult processes of reasoning; but to
those habits of accurate and patient attention to
the operations of his own mind, which, from his
early years, it was the great business of his life
to cultivate. It may be proper to add, that the
epithets primary and secondary, now universally
employed to mark the distinction in question,
were first introduced by Locke ; a circumstance
posing his Treatise of Human Nature. Is it not probable, that be was partly attracted to it, by associations similar to
those which presented themselves to the fancy of Cicero, when he visited the walks of the Academy ?
In the beginning of Descartes’ dissertation upon Method, he has given a very interesting account of the pursuits which
occupied his youth, and of the considerations which suggested to him the bold undertaking of reforming philosophy.
1 Such too is the judgment pronounced by D’Alembert. “ Les Mathematiques, dont Descartes semble avoir fait assez
peu de cas, font neanmoins aujourd’hui la partie la plus solide et la moins conteste'e de sa gloire.” To this he adds a very in¬
genious reflection on the comparative merits of Descartes, considered as a geometer and as a philosopher. “ Comme philo-
sophe, il a peut-etre dte aussi grand, mais il n’a pas dte si heureux. La Geometrie, qui par la nature de son objet doit
toujours gagner sans perdre, ne pouvoit manquer, etant manide par un aussi grand genie de faire des progres tres-sensibles
et apparens pour tout le monde. La Philosophie se trouvoit dans un etat bien different, tout y etoit a commencer;
et que ne content point les premiers pas en tout genre ! le m'erite de les faire dispense de cclui d'en faire de grands."—Disc. Prelim.
2 “ The names of simple ideas are not capable of any definitions; the names of all complex ideas are. It has not, that I
know, been yet observed by any body, what words are, and what are not capable of being defined.”—(Locke’s Essay,
Book iii. chap. iv. § iv.)—Compare this with the Principia of Descartes, 1.10.; and with Lord Stair’s Philologia Nova Expe~
rimentalis, pp. 9 and 79, printed at Leyden in 1686.
DISSERTATION FIRST.
63
which may have contributed to throw into the
shade the merits of those inquirers who had pre¬
viously struck into the same path.
As this last article of the Cartesian system
has a close connection with several of the most
refined conclusions yet formed concerning the
intellectual phenomena, I feel it due to the me¬
mory of the author, to pause for a few moments,
in order to vindicate his claim to some leading
ideas, commonly supposed hy the present race
of metaphysicians to be of much later origin. In
doing so, I shall have an opportunity, at the
same time, of introducing one or two remarks,
which, I trust, will he useful in clearing up the
obscurity, which is allowed by some of the ablest
followers of Descartes and Locke, still to hang
over this curious discussion.
I have elsewhere observed, that Descartes has
been very generally charged by the writers of
the last century, with a sophistical play upon
words in his doctrine concerning the non-exist¬
ence of secondary qualities; while, in fact, he
was the first person by whom the fallacy of this
scholastic paralogism was exposed to the world.1
In proof of this, it might be sufficient to refer to
his own statement, in the first part of the Prin-
cipia ;2 hut, for a reason which will immediate¬
ly appear, I think it more advisable, on this occa¬
sion, to borrow the words of one of his earliest and
ablest commentators. <{ It is only (says Father
Malehranche) since the time of Descartes, that
to those confused and indeterminate questions,
whether fire is hot, grass green, and sugar sweet,
philosophers are in use to reply, hy distinguish¬
ing the equivocal meaning of the words express¬
ing sensible qualities. If hy heat, cold, and
savour, you understand such and such a dispo¬
sition of parts, or some unknown motion of
sensible qualities, then fire is hot, grass green,
and sugar sweet. But if by heat and other
qualities you understand what I feel hy fire,
what I see in grass, &c. fire is not hot, nor grass
green ; for the heat I feel, and the colours I see,
are only in the soul.”5 It is surprising how this,
and other passages to the same purpose in Male¬
hranche, should have escaped the notice of Dr
Reid; for nothing more precise on the ambigui¬
ty in the names of secondary qualities is to be
found in his own works. It is still more sur¬
prising that Buffier, who might have been ex¬
pected to have studied with care the speculations
of his illustrious countryman, should have di¬
rectly charged, not only Descartes, but Male¬
hranche, with maintaining a paradox, whicx
they were at so much pains to banish from the
schools of philosophy.4
The important observations of Descartes upon
this subject, made their way into England very
soon after his death. They are illustrated at
considerable length, and with great ingenuity,
hy Glanville, in his Scepsis Scientifica, published
“Descartes, Malebranche, and Locke, revived the distinction between primary and secondary qualities. But thev
made the secondary qualities mere sensations, and the primary ones resemblances of our sensations. They maintained
that colour, sound, and heat, are not any thing in bodies, but sensations of the mind. The paradoxes of these philo¬
sophers were only an abuse of words. For when they maintain, as an important modern discovery, that there is no heat in
the fire, they mean no more than that the fire does not feel heat, which every one knew before.”—Reid’s Inquiry, chan,
v. sect. viii.
2 See sections Ixix. Ixx. Ixxi. The whole of these three paragraphs is highly interesting; but I shall only quote two
sentences, which are fully sufficient to show, that, in the above observations, I have done Descartes no more than strict
justice.
“ Patet itaque in re idem esse, cum dicimus nos percipere colores in objectis, ac si diceremus nos percipere aliquid in
objectis, quod quidem quid sit ignoramus, sed a quo efficitur in nobis ipsis sensus quidam valde manifestus et perspicuus,
qui vocatur sensus cobrum. Cum vero putamus nos percipere colores in objectis, etsi revera nesciamus quidnam
sit quod tunc nomine colons appellamus, nec ullam similitudinem intelligere possimus, inter colorem quem supponimus
esse in objectis, et ilium quem experimur esse in sensu, quia tamen hoc ipsum non advertimus, et multa alia sunt, ut mag¬
nitude, figura, numerus, &c. quae clare percipimus not aliter a nobis sentiri vel intelligi, quam ut sunt, aut saltern esse
possunt in objectis, facile, m eum errorem delabimur, ut judicemus id, quod in objectis vocamus colorem, esse quid omnino
simile colon quem sentimus, atque ita ut id quod nullo modo percipimus, a nobis clare percipi arbitraremur.”
3 Recherche de la Verite, Livre vi. chap. ii.
J ai admire souvent que d’aussi grands hommes que Descartes et Malebranche, avec leurs sectateurs, fissent valoir,
comme une rare decouverte de leur philosophie, que la chaleur etoit dans nous-mtmes et nullement dans le feu ; au lieu que le
commun des hommes trouvoient que la chaleur etoit dans le feu aussi lien que dans nous Mais en ce fameux debat, de
quoi s’agit-il ? Uniquement de 1’imperfection du langage, qui causoit une idee confuse par le mot de chaleur, ce mot expri-
mant egalement deux choses, qui a la verite ont quelque rapport ou analogie, et pourtant qui sont tres diff'erentes; savoir,
1. le sentiment de chaleur qui nous eprouvons en nous ; 2. la disposition qui est dans le feu a produire en nous ce senti¬
ment de chaleur.”—Cours de Sciences, par le Pere Buffier, p. 819. A Paris, 1732.
64
PRELIMINARY DISSERTATIONS.
about thirteen years before Malebranche’s Search
after Truth. So slow, however, is the progiess
of good sense, when it has to struggle against
the prejudices of the learned, that, as lately as
1713, the paradox so clearly explained and re¬
futed by Descartes, appears to have kept some
footing in the English universities. In a papei
of the Guardian, giving an account of a visit
paid by Jack Lizard to his mother and sisters,
after a year and half s residence at Oxford, the
following precis is given of his logical attain¬
ments. “ For the first week (it is said) Jack
dealt wholly in paradoxes. It was a common
jest with him to pinch one of his sister s lap
dogs, and afterwards prove he could not feel it.
When the girls were sorting a set of knots, he
would demonstrate to them that all the ribbons
were of the same colour ; or rather, says Jack,
of no colour at all. My Lady Lizard herself,
though she was not a little pleased with her son’s
improvements, was one day almost angry with
him ; for having accidentally burnt her fingers
as she was lighting the lamp for her tea-pot, in
the midst of her anguish, Jack laid hold of the
opportunity to instruct her, that there was no
such thing as heat in the fire.”
This miserable quibble about the non-exist¬
ence of secondary qualities, never could have
attracted the notice of so many profound think¬
ers, had it not been for a peculiar difficulty con¬
nected with our notions of colour, of which I do
not know anyone English philosopher who seems
to have been sufficiently aware. That this qua¬
lity belongs to the same class with sounds, smells,
tastes, heat and cold, is equally admitted by the
partisans of Descartes and of Locke ; and must,
indeed, appear an indisputable fact to all who
are capable of reflecting accurately on the sub¬
ject. But still, between colour and the other
qualities now mentioned, a very important dis¬
tinction must be allowed to exist. In the case
of smells, tastes, sounds, heat and cold, every
person must immediately perceive, that his senses
give him only a relative idea of the external
quality; in other words, that they only convey
to him the knowledge of the existence of cer¬
tain properties or powers in external objects,
which fit them to produce certain sensations in
his mind; and, accordingly, nobody ever hesitat¬
ed a moment about the truth of this part of the
Cartesian philosophy, in so far as these qualities
alone are concerned. But, in the application of
the same doctrine to colour, I have conversed
with many, with whom I found it quite in vain
to argue; and this, not from any defect in their
reasoning powers, but from their incapacity to
reflect steadily on the subjects of their conscious¬
ness ; or rather, perhaps, from their incapacity
to separate, as objects of the understanding, two
things indissolubly combined by early and con¬
stant habit, as objects of the imagination. The
silence of modern metaphysicians on this head
is the more surprising, as D’Alembert long ago
invited their attention to it as one of the most
wonderful phenomena in the history of the hu¬
man mind. “ The bias we acquire,” I quote
his own words, c< in consequence of habits con¬
tracted in infancy, to refer to a substance ma¬
terial and divisible, what really belongs to a sub¬
stance spiritual and simple, is a thing well
worthy of the attention of metaphysicians. No¬
thing,” he adds, “ is perhaps more extraordi¬
nary, in the operations of the mind, than to see
it transport its sensations out of itself, and to
spread them, as it were, over a substance to
which they cannot possibly belong.”—It would
be difficult to state the fact in question in terms
more brief, precise, and perspicuous.
That the illusion, so well described in the
above quotation, was not overlooked by Des¬
cartes and Malebranche, appears unquestionable,
from their extreme solicitude to reconcile it with
that implicit faith, which, from religious con¬
siderations, they conceived to be due to the testi¬
mony of those faculties with which our Maker
has endowed us. Malebranche, in particular, is
at pains to distinguish between the sensation, and
the judgment combined with it. “ The sensa¬
tion never deceives us; it differs in no respect
from what we conceive it to be. The judgment,
too, is natural, or rather (says Malebranche),
it is only a sort of compound sensation ;x but this
1 He would have expressed himself more accurately, if he had said, that the judgment is indissolubly combined with the
sensation ; but his meaning is sufficiently obvious.
DISSERTATION FIRST.
65
judgment leads us into no error with respect to
philosophical truth. The moment we exercise
our reason, we see the fact in its true light, and
can account completely for that illusive appear¬
ance which it presents to the imagination.”
Not satisfied, however, with this solution of
the difficulty, or rather perhaps apprehensive
that it might not appear quite satisfactory to
some others, he has called in to his assistance
the doctrine of original sin; asserting, that all
the mistaken judgments which our constitution
leads us to form concerning external objects^and
their qualities, are the consequences of the fall
of our first parents ; since which adventure (as it
is somewhat irreverently called by Dr Beattie),
it requires the constant vigilance of reason to
guard against the numberless tricks and im¬
postures practised upon us by our external
senses.1 In another passage, Malebranche ob¬
serves very beautifully (though not very con¬
sistently with his theological argument on the
same point), that our senses being given us for
the preservation of our bodies, it was requisite
for our well-being, that we should judge as we
do of sensible qualities. “ In the case of the
sensations of pain and of heat, it was much
more advantageous that we should seem to feel
them in those parts of the body which are im¬
mediately affected by them, than that we should
associate them with the external objects by which
they are occasioned; because pain and heat,
having the power to injure our members, it was
necessary that we should be warned in what
place to apply the remedy; whereas colours not
being likely, in ordinary cases, to hurt the eye,
it would have been superfluous for us to know
that they are painted on the retina. On the
contrary, as they are only useful to us, from the
information they convey with respect to things
external, it was essential that we should be so
formed as to attach them to the corresponding
objects on which they depend.”2
The two following remarks, which I shall state
with all possible brevity, appear to me to go far
towards a solution of the problem proposed by
D’Alembert.
1. According to the new theory of vision com¬
monly (but, as I shall afterwards show, not alto¬
gether9% ) ascribed to Dr Berkeley, lineal dis¬
tance from the eye is not an original perception of
sight. In the meantime, from the first moment
that the eye opens, the most intimate connection
must necessarily be established between the notion
of colour and those of visible extension and figure.
At first, it is not improbable that all of them
may be conceived to be merely modifications of
the mind; but, however this may be, the mani¬
fest consequence is, that when a comparison
between the senses of Sight and of Touch has
taught us to refer to a distance the objects of
the one, the indissolubly associated sensations
of the other must of course accompany them,
how far soever that distance may extend.3
2. It is well known to be a general law of our
constitution, when one thing is destined, either
by nature or by convention, to be the sign of
another, that the mind has a disposition to pass
on, as rapidly as possible, to the thing signified,
without dwelling on the sign as an object worthy
of its attention. The most remarkable of all ex-
1 “ We are informed by Father Malebranche, that the senses were at first as honest faculties as one could desire to be
endued with, till after they were debauched by original sin ; an adventure from which they contracted such an invincible
propensity to cheating, that they are now continually lying in wait to deceive us.”—Essay on Truth, p. 241, second edition.
2 Recherche de la Verite, Liv. i. chap. xiii. § 5. In Dr Iteid’s strictures on Descartes and Locke there are two remarks
which I am at a loss how to reconcile. “ Colour,” says he, “ differs from other secondary qualities in this, that whereas
the name of the quality is sometimes given to the sensation which indicates it, and is occasioned by it, we never, as far as
I can judge, give the name of colour to the sensation, but to the quality only.” A few sentences before, lie had observed,
“ That when we think or speak of any particular colour, however simple the notion may seem to be which is presented to
the imagination, it is really in some sort compounded. It involves an unknown cause, and a known effect. The name of
colour belongs indeed to the cause only, and not to the effect. But as the cause is unknown, we can form no distinct con¬
ception of it, but by its relation to the known effect. And, therefore, both go together in the imagination, and are so close¬
ly united, that they are mistaken for one simple object of thought.”—Inquiry, chap. vi. sect. 4.
These two passages seem quite inconsistent with each other. If in the perception of colour, the sensation and the qua¬
lity “ be so closely united as to be mistaken for one single object of thought,” does it not obviously follow, that it is to
this compounded notion the name of colour must, in general, be given ? On the other hand, when it is said that the name of
colour is never given to the sensation, hut to the quality only, does not this imply, that every time the word is pronounced, the
quality is separated from the sensation, even in the imaginations of the vulgar,?
3 See Note M.
DISS. I. PATIT I. I
66
PRELIMINARY DISSERTATIONS.
amples of this occurs in the acquired perceptions
of sight, where our estimates of distance are
frequently the result of an intellectual process,
comparing a variety of different signs together,
without a possibility on our part, the moment
afterwards, of recalling one single step of the
process to our recollection. Our inattention to
the sensations of colour, consiclered as affections
of the Mind, or as modifications of our own
being, appears to me to he a fact of precisely
the same description; for all these sensations
were plainly intended by nature to perform the
office of signs, indicating to us the figures and
distances of things external. Of their essential
importance in this point of view, an idea may
be formed, by supposing for a moment the whole
face of nature to exhibit only one uniform colour,
without the slightest variety even of light and
shade. Is it not self-evident that, on this sup¬
position, the organ of sight would be entirely
useless, inasmuch as it is by the varieties of
colour alone that the outlines or visible figures
of bodies are so defined, as to be distinguishable
one from another ? Nor could the eye, in this
case, give us any information concerning diver¬
sities of distance ; for all the various signs of it,
enumerated by optical writers, pre-suppose the
antecedent recognition of the bodies around us,
as separate objects of perception. It is not there¬
fore surprising, that signs so indispensably sub¬
servient to the exercise of our noblest sense,
should cease, in early infancy, to attract notice
as the subjects of our consciousness; and that
afterwards they should present themselves to the
imagination rather as qualities of Matter, than
as attributes of Mind.1
To this reference of the sensation of colour
to the external object, I can think of nothing so
analogous as the feelings we experience in sur¬
veying a library of books. We speak of the
volumes piled up on its shelves, as treasures or
magazines of the knowledge of past ages; and
contemplate them with gratitude and reverence,
as inexhaustible sources of instruction and delight
to the mind. Even in looking at a page of print
or of manuscript, we are apt to say, that the ideas
we acquire are received by the sense of sight;
and we are scarcely conscious of a metaphor,
when we employ this language. On such oc¬
casions we seldom recollect, that nothing is per¬
ceived by the eye but a multitude of black strokes
drawn upon white paper, and that it is our own
acquired habits which communicate to these
strokes the whole of that significancy whereby
they are distinguished from the unmeaning
scrawling of an infant or a changeling. The
knowledge which we conceive to be preserved in
books, like the fragrance of a rose, or the gild¬
ing of the clouds, depends, for its existence, on
the relation between the object and the percipient
mind; and the only difference between the two
cases is, that in the one, this relation is the local
and temporary effect of conventional habits; in
the other, it is the universal and the unchange¬
able work of nature. The art of printing, it is
to be hoped, will in future render the former
relation, as well as the latter, coeval with our
species; but, in the past history of mankind, it
is impossible to say how often it may have been
dissolved. What vestiges can now be traced of
those scientific attainments which, in early times,
drew to Egypt, from every part of the civilised
world, all those who were anxious to be initia¬
ted in the mysteries of philosophy ? The sym¬
bols which still remain in that celebrated coun¬
try, inscribed on eternal monuments, have long
lost the correspondent which reflected upon
them their own intellectual attributes. To us
' In Dr Iteid’s Inquiry, he has introduced a discussion concerning the perception of visible figure, which has puzzled me
since the first time (more than forty years ago) that I read his work. The discussion relates to this question, “ Whether
there be any sensation proper to visible figure, by which it is suggested in vision ?” The result of the argument is, that
“ our eye might have been so framed as to suggest the figure of the object, without suggesting colour, or any other quality ;
and, of consequence, there seems to be no sensation appropriated to visible figure; this quality being suggested immediately
by the material impression upon the organ, of which impression we are not conscious.”—Inquiry, chap. vi. sect. 8. To
my apprehension, nothing can appear more manifest than this, that, if there had been no variety in our sensations of colour,
and still more, if we had had no sensation of colour whatsoever, the organ of sight could have given us no information,
either with respect to figures or to distances ; and, of consequence, would have been as useless to us, as if we had been af¬
flicted, from the moment of our birth, with a gutta serena.
DISSERTATION FIRST.
67
they are useless and silent, and serve only to at¬
test the existence of arts, of which it is impos¬
sible to unriddle the nature and the objects.
 Variis nunc sculpta figuris
Marmora, trunca tamen visuntur mutaque nobis;
Signa repertorum tuimur, cecidere reperta.
What has now been remarked with respect to
written characters, may be extended very nearly
to oral language. WTien we listen to the dis¬
course of a public speaker, eloquence and per¬
suasion seem to issue from his lips; and we are
little aware, that we ourselves infuse the soul
into every word that he utters. The case is
exactly the same when we enjoy the conversa¬
tion of a friend. We ascribe the charm entirely
to his voice and accents; but without our co¬
operation, its potency would vanish. How very
small the comparative proportion is, which, in
such cases, the words spoken contribute to the
intellectual and moral effect, I have elsewhere
endeavoured to show.
I have enlarged on this part of the Cartesian
system, not certainly on account of its intrinsic
value, as connected with the theory of our ex¬
ternal perceptions (although even in this respect
of the deepest interest to every philosophical in¬
quirer), but because it affords the most palpable
and striking example I know of, to illustrate the
indissoluble associations established during the
period of infancy between the intellectual and
the material worlds. It was plainly the inten¬
tion of nature, that our thoughts should be ha¬
bitually directed to things external; and accord¬
ingly the bulk of mankind are not only indis-
posed to study the intellectual phenomena, but
are incapable of that degree of reflection which
is necessary for their examination. Hence it is,
that when we begin to analyse our own internal
constitution, we find the facts it presents to us
so very intimately combined in our conceptions
with the qualities of matter, that it is impossible
for us to draw distinctly and steadily the line
between them ; and that, when Mind and Mat¬
ter are concerned in the same result, the former
is either entirely overlooked, or is regarded only
as an accessary principle, dependent for its ex¬
istence on the latter. To the same cause it is
owing, that we find it so difficult (if it be at all
practicable) to form an idea of any of our intel¬
lectual operations, abstracted from the images
suggested by their metaphorical names. It was
objected to Descartes by some of his contempo¬
raries, that the impossibility of accomplishing
the abstractions which he recommended, fur¬
nished of itself a strong argument against the
soundness of his doctrines.1 The proper an¬
swer to this objection does not seem to have oc¬
curred to him, nor, so far as I know, to any
of his successors;—that the abstractions of the
understanding are totally different from the ab¬
stractions of the imagination i and that we may
reason with most logical correctness about things
considered apart, which it is impossible, even in
thought, to conceive as separated from each
other. His own speculations concerning the
indissolubility of the union established in the
mind between the sensations of colour and the
primary qualities of extension and figure, might
have furnished him, on this occasion, with a tri¬
umphant reply to his adversaries; not to men¬
tion that the variety of metaphors, equally fitted
to denote the same intellectual powers and ope¬
rations, might have been urged as a demonstra¬
tive proof, that none of these metaphors have
any connection with the general laws to which
it is the business of the philosopher to trace the
mental phenomena.
When Descartes established it as a general
principle, that nothing conceivable by the power of
imagination could throw any light on the operations
of thought (a principle which I consider as ex¬
clusively his own), he laid the foundation-stone
of the Experimental Philosophy of the Human
Mind. That the same truth had been previous¬
ly perceived, more or less distinctly, by Bacon
and others, appears probable from the general
complexion of their speculations; but which of
them has expressed it with equal precision, or
laid it down as a fundamental maxim in their
logic ? It is for this reason, that I am disposed
to date the origin of the true Philosophy of
Mind from the Principia of Descartes rather
1 See, in particular, Gassendi Opera, Tom. III. pp. 300, 301 Lugduni, 1058.
68
preliminary dissertations.
than from the Organon of Bacon, or the Essay
of Locke ; without, however, meaning to com¬
pare the French author with our two countiy-
men, either as a contributor to our stock of facts
relating to the intellectual phenomena, or as the
author of any important conclusion concerning
the general laws to which they may he referred.
It is mortifying to reflect on the inconceivably
small number of subsequent inquirers by whom
the spirit of this cardinal maxim has been fully
seized; and that, even in our own times, the
old and inveterate prejudice to which it is op¬
posed, should not only have been revived with
success, but should have been very generally re¬
garded as an original and profound discovery
in metaphysical science. These circumstances
must plead my apology for the space I have as¬
signed to the Cartesian Metaphysics in the
crowded historical picture which I am at present
attempting to sketch. The fulness of illustra¬
tion which I have bestowed on the works of the
master, Avill enable me to pass over those of his
disciples, and even of his antagonists, with a
correspondent brevity.1
After having said so much of the singular
merits of Descartes as the father of genuine me¬
taphysics, it is incumbent on me to add, that his
errors in this science were on a scale ol propor¬
tionate magnitude. Of these the most promi¬
nent (for I must content myself with barely
mentioning a few of essential importance) were
his obstinate rejection of all speculations about
final causes;2 his hypothesis concerning the
lower animals, which he considered as mere ma¬
chines;3 4 his doctrine of innate ideas, as under¬
stood and expounded by himself;* his noted para¬
dox of placing the essence of mind in thinking,
and of matter in extension ;5 and his new modi¬
fication of the ideal theory of perception, adopt¬
ed afterwards, with some very slight changes,
by Malebranche, Locke, Berkeley, and Hume.0
To some of these errors I shall have occasion to
refer in the sequel of this Discourse. The fore¬
going slight enumeration is sufficient for my
present purpose.
In what I have hitherto said of Descartes, I
have taken no notice of his metaphysico-physio-
logical theories relative to the connection be¬
tween soul and body. Of these theories, how¬
ever, groundless and puerile as they are, it is
necessary for me, before I proceed farther, to
say a few words, on account of their extensive
and lasting influence on the subsequent history
of the science of Mind, not only upon the Con¬
tinent, but in our own island.
The hypothesis of Descartes, which assigns to
the soul for its principal seat the pineal gland or
conarion, is known to every one who has perused
1 The Cartesian doctrine concerning the secondary qualities of matter, is susceptible of various other important applica¬
tions. Might it not be employed, at least as an argumcnlum ad homincm against Mr Hume and others, who, admitting this
part of the Cartesian system, seem nevertheless to have a secret leaning to the scheme of materialism ? Mr Hume has
somewhere spoken of that little agitation of the brain xve call thought. If it be unphilosophical to confound our sensations of co-
lour, of heat, and of cold, with such qualities as extension, figure, and solidity, is it not, if possible, still moie so, to con¬
found with these qualities the phenomena of thought, of volition, and of moral emotion ? ,
2 It is not unworthy of notice, that, in spite of his own logical rules, Descartes sometimes seems insensibly to adopt,
on this subject, the common ideas and feelings of mankind. Several instances ot this occur in his treatise on the Passions,
where he offers various conjectures concerning the uses to which they are subservient. Ihe following sentence is more
peculiarly remarkable : “ Mihi persuadere nequeo, naturam indedisse hominibus ullum affectum qui semper vitiosuo sit,
nullumque usum bonuni et laudabilem habeat.”—Art. clxxv. ,
3 This hypothesis never gained much ground in England ; and yet a late writer of distinguished eminence m some
branches of science, has plainly intimated that, in his opinion, the balance of probabilities inclined in its favour. ‘ I omit
mentioning other animals here,” says Mr Kirwan in his Metaphysical Essays, “ as it is at least doubtful whether they are not
mere automatons."—-Met. Essays, p. 41. Eond. 1809. _ _
4 I have added the clause in Italics, because, in Descartes’ reasonings on this question, there is no inconsiderable portion
of most important truth, debased by a large and manifest alloy of error. _
5 To this paradox may be traced many of the conclusions of the author, both on physical and on metaphysical subjects.
One of the most characteristical features, indeed, of his genius, is the mathematical concatenation of his opinions, even on
questions which, at first sight, seem the most remote from each other; a circumstance which, when combined with the ex¬
traordinary perspicuity of Ins style, completely accounts for the strong hold his philosophy took of every mind, thoroughly
initiated, at an early period of life, in its principles and doctrines. In consequence of conceiving the essence ot matter to
consist in extension, he was necessarily obliged to maintain the doctrine of a universal plenum; upon which doctrine the
theory of the Vortices came to be grafted by a very short and easy process. The same idea forced him, at the very outset
of his Metaphysical Meditations, to assert, much more dogmatically than his premises seem to warrant, the non-extension of
Mind; and led him on many occasions to blend, very illogically, this comparatively disputable dogma, with the facts he has to
state concerning the mental phenomena.
4 See Note N.
DISSERTATION FIRST.
f,9
the Alma of Prior. It is not, perhaps, equally
known, that the circumstance which determined
him to fix on this particular spot, was the very
plausible consideration, that, among the different
parts of the brain, this was the only one he
could find, which, being single and central,
was fitted for the habitation of a being, of which
he conceived unity and indivisibility to be essen¬
tial and obvious attributes.1 In what manner
the animal spirits, by their motions forwards and
backwards in the nervous tubes, keep up the
communication between this gland and the dif¬
ferent parts of the body, so as to produce the
phenomena of perception, memory, imagination,
and muscular motion, he has attempted parti¬
cularly to explain; describing the processes by
which these various effects are accomplished,
with as decisive a tone of authority, as if he had
been demonstrating experimentally the circula¬
tion of the blood. How curious to meet with
such speculations in the works of the same phi¬
losopher, who had so clearly perceived the ne¬
cessity, in studying the laws of Mind, of ab¬
stracting entirely from the analogies of Matter;
and who, at the outset of his inquiries, had car¬
ried his scepticism so far, as to require a proof
even of the existence of his own body ! To
those, however, who reflect with attention on
the method adopted by Descartes, this inconsist¬
ency will not appear so inexplicable as at first
sight may be imagined; inasmuch as the same
scepticism which led him to suspend his faith in
his intellectual faculties till he had once proved
to his satisfaction, from the necessary veracity
of God, that these faculties were to be regarded
as divine oracles, prepared him, in all the sub¬
sequent steps of his progress, to listen to the
suggestions of his own fallible judgment, with
more than common credulity and confidence.
The ideas of Descartes, respecting the com¬
munication between soul and body, are now so
universally rejected, that I should not have al¬
luded to them here, had it not been for their
manifest influence in producing, at the distance
of a century, the rival hypothesis of Dr Hartley.
The first traces of this hypothesis occur in some
queries of Sir Isaac Newton, which he was pro¬
bably induced to propose, less from the convic¬
tion of his own mind, than from a wish to turn
the attention of philosophers to an examination
of the correspondent part of the Cartesian sys¬
tem. Not that I would be understood to deny
that this great man seems, on more than one oc¬
casion, to have been so far misled by the ex¬
ample of his predecessor, as to indulge himself
in speculating on questions altogether unsuscep¬
tible of solution. In the present instance, how¬
ever, there cannot, I apprehend, be a doubt,
that it was the application made by Descartes of
the old theory of animal spirits, to explain the
mental phenomena, which led Newton into that
train of thinking which served as the ground¬
work of Hartley’s Theory of Vibrations.2
It would be useless to dwell longer on the re-
1 See in particular, the treatise De Passionibus, Art. 31. 32. See also Note O.
2 The physiological theory of Descartes, concerning the connection between soul and body, was adopted, together with
some of his sounder opinions, by a contemporary English philosopher, Mr Smith of Cambridge, whom I had occasion to
mention in a former note ; and that, for some time after the beginning of the eighteenth century, it continued to afford
one of the chief subjects of controvers}r between the two English universities, the Alma of Prior affords incontestable evi¬
dence. From the same poem it appears, how much the reveries of Descartes about the seat of the soul, contributed to wean
the wits of Cambridge from their former attachment to the still more incomprehensible pneumatology of the schoolmen.
 Here Matthew said,
Alma in verse, in prose the mmd
By Aristotle’s pen defin’d,
Throughout the body squat or tall,
Is, bona fide, all in all,
And yet, slap-dash, is all again
In every sinew, nerve, and vein ;
Buns here and there like Hamlet’s Ghost,
While everywhere she rules the roast.
This system, Bichard, we are told,
The men of Oxford firmly hold ;
The Cambridge wits, you know, deny
With ipse dixit to comply.
They say, (for in good truth they speak
With small respect of that old Greek)
That putting all his words together,
* ’Tis three blue beans in one blue bladder.
70
PRELIMINARY DISSERTATIONS.
veries of a philosopher, much better known to
the learned of the present age by the boldness
of his exploded errors, than by the profound and
important truths contained in his works. At
the period when he appeared, it may perhaps be
questioned, whether the truths which he taught,
or the errors into which he fell, were most in¬
structive to the world. The controversies pro¬
voked by the latter had certainly a more imme¬
diate and palpable effect in awakening a general
spirit of free inquiry. To this consideration
may be added an ingenious and not altogether
unsound remark of D’Alembert, that “ when
absurd opinions are become inveterate, it is
sometimes necessary to replace them by other
errors, if nothing better can be done. Such (he
continues) are the uncertainty and the vanity of
the human mind, that it has always need of an
opinion on which it may lean; it is a child to
whom a play-thing must occasionally be present¬
ed, in order to get out of its hands a mischie¬
vous weapon; the play-thing will soon be aban¬
doned, when the light of reason begins to dawn.1
Among the opponents of Descartes, Gassendi
was one of the earliest, and by far the most for¬
midable. No two philosophers were ever more
strongly contrasted, both in point of talents and
of temper; the former as far superior to the
latter in originality of genius—in powers of con¬
centrated attention to the phenomena of the in¬
ternal world—in classical taste—in moral sensi¬
bility, and in all the rarer gifts of the mind, as
he fell short of him in erudition—in industry as
a book-maker—in the justness of his logical
views, so far as the phenomena of the material
universe are concerned—and, in general, in
those literary qualities and attainments, of which
the bulk of mankind either are, or think them¬
selves best qualified to form an estimate. The
reputation of Gassendi, accordingly, seems to
have been at its height in his own lifetime ; that
of Descartes made but little progress, till a con¬
siderable time after his death.
The comparative justness of Gassendi’s views
in natural philosophy may be partly, perhaps
chiefly, ascribed to his diligent study of Bacon’s
works ; which Descartes (if he ever read them),
has nowhere alluded to in his writings. This
extraordinary circumstance in the character of
Descartes is the more unaccountable, that not
only Gassendi, but some of his other corre¬
spondents, repeatedly speak of Bacon in terms
which one should think could scarcely have fail¬
ed to induce him to satisfy his own mind whe¬
ther their encomiums were well or ill founded.
One of these, while he contents himself, from
very obvious feelings of delicacy, with mention¬
ing the Chancellor of England as the person
who, before the time of Descartes, had entertained
the justest notions about the method of prose¬
cuting physical inquiries, takes occasion, in the
same letter, to present him, in the form of a
friendly admonition from himself, with the fol¬
lowing admirable summary of the instauratio
magna. <c To all this it must be added, that no
architect, however skilful, can raise an edifice,
unless he be provided with proper materials. In
like manner, your method, supposing it to be
perfect, can never advance you a single step in
the explanation of natural causes, unless you are
in possession of the facts necessary for determin¬
ing their effects. They who, without stirring
from their libraries, attempt to discourse con¬
cerning the works of nature, may indeed tell us
what sort of world they would have made, if
God had committed that task to their ingenuity ;
but, without a wisdom truly divine, it is impos¬
sible for them to form an idea of the universe,
at all approaching to that in the mind of its
Creator. And, although your method promises
everything that can be expected from human
Alma they strenuously maintain,
Sits cock-horse on her throne the brain,
And from that seat of thought dispenses
Her sovereign pleasure to the senses, &c. &c.
The whole poem, from beginning to end, is one continued piece of ridicule upon the various hypotheses of physiologists
concerning the nature or the communication between soul and body. The amusing contrast between the solemn absurdity
or these disputes, and the light pleasantry of the excursions to which they lead the fancy of the poet, constitutes the prin«
cipal charm of this performance; by far the most original and characteristical of all Prior’s Works.
1 See Note P. *
DISSERTATION FIRST.
71
genius, it does not, therefore, lay any claim to
the art of divination; hut only boasts of dedu¬
cing from the assumed data, all the truths
which follow from them as legitimate conse¬
quences ; which data can, in physics, he nothing
else but principles previously established by ex¬
periment.”1 In Gassendi’s controversies with
Descartes, the name of Bacon seems to be studi¬
ously introduced on various occasions, in a man¬
ner still better calculated to excite the curiosity
of his antagonist; and in his historical review
of logical systems, the heretical attempt which
gave birth to the Novum Organon is made the sub¬
ject of a separate chapter, immediately preced¬
ing that which relates to the Metaphysical Medi¬
tations of Descartes.
The partiality of Gassendi for the Epicurean
physics, if not originally imbibed from Bacon,
must have been powerfully encouraged by the
favourable terms in which he always mentions
the Atomic or Corpuscular theory. In its con¬
formity to that luminous simplicity which every¬
where characterises the operations of nature,
this theory certainly possesses a decided superio¬
rity over all the other conjectures of the ancient
philosophers concerning the material universe ;
and it reflects no small honour on the sagacity
both of Bacon and of Gassendi, to have perceiv¬
ed so clearly the strong analogical presumption
which this conformity afforded in its favour,
prior to the unexpected lustre thrown upon it by
the researches of the Newtonian school. With
all his admiration, however, of the Epicurean
physics, Bacon nowhere shows the slightest
leaning towards the metaphysical or ethical doc¬
trines of the same sect; hut, on the contrary,
considered (and, I apprehend, rightly consider¬
ed) the atomic theory as incomparably more hos¬
tile to atheism, than the hypothesis of four
mutable elements, and of one immutable fifth
essence. In this last opinion, there is every
reason to believe that Gassendi fully concurred;
more especially, as he was a zealous advocate for
the investigation offinal causes, even in inquiries
strictly physical. At the same time, it cannot be
denied, that, on many questions, both of Metaphy¬
sics and of Ethics, this very learned theologian
(one of the most orthodox, professedly, of whom
the Catholic church has to boast), carried his
veneration for the authority of Epicurus to a de¬
gree bordering on weakness and servility; and
although, on such occasions, he is at the utmost
pains to guard his readers against the dangerous
conclusions commonly ascribed to his master, he
has nevertheless retained more than enough of
his system, to give a plausible colour to a very
general suspicion, that he secretly adopted more
of it than he chose to avow.
As Gassendi’s attachment to the physical doc¬
trines of Epicurus, predisposed him to give an
easier reception than he might otherwise have
done to his opinions in Metaphysics and in
Ethics, so his unqualified contempt for the hy¬
pothesis of the Vortices seems to have created
in his mind an undue prejudice against the spe¬
culations of Descartes on all other subjects. His
objections to the argument by which Descartes
has so triumphantly established the distinction
between Mind and Matter, as separate and he¬
terogeneous objects of human knowledge, must
now appear, to every person capable of forming
a judgment upon the question, altogether frivo¬
lous and puerile; amounting to nothing more
than this, that all our knowledge is received by
the channel of the external senses,—insomuch,
that there is not a single object of the under¬
standing which may not he ultimately analysed
into sensible images; and, of consequence, that
when Descartes proposed to abstract from these
images in studying the mind, he rejected the
only materials out of which it is possible for our
faculties to rear any superstructure. The sum
of the whole matter is (to use his own language),
that c{ there is no real distinction between ima¬
gination and intellection ; meaning, by the former
of these words, the power which the mind pos¬
sesses of representing to itself the material ob¬
jects and qualities it has previously perceived.
It is evident, that this conclusion coincides ex¬
actly with the tenets inculcated in England at
the same period by his friend Hobbes,2 as well
as with those revived at a later period by Dide-
1 See the first Epistle to Descartes, prefixed to his Treatise on the Passions. Amstel. 1664.
* The affection of Gassendi for Hobbes, and his esteem for his writings, are mentioned in very strong terms by oor-
PRELIMINARY DISSERTATIONS.
rot, Horne Tooke, and many other writers, "both
French and English, who, while they were only
repeating the exploded dogmas of Epicurus,
fancied they were pursuing, with miraculous
success, the new path struck out by the genius
of Locke.
It is worthy of remark, that the argument em¬
ployed by Gassendi against Descartes, is copied
almost verbatim from his own version of the ac¬
count given by Diogenes Laertius of the sources
of our knowledge, according to the principles of
the Epicurean philosophy:1—so very little is
there of novelty in the consequences deduced
by modern materialists from the scholastic pro¬
position, JLihil est in intellectu quod nonfuitprius
in sensu. The same doctrine is very concisely
and explicitly stated in a maxim formerly quot¬
ed from Montaigne, that cc the senses are the
beginning and end of all our knowledge—a
maxim which Montaigne learned from his oracle
Raymond de Sebonde; which, by the present
race of French philosophers, is almost univer¬
sally supposed to be sanctioned by the authority
of Locke; and which, if true, would at once
cut up by the roots, not only all metaphysics,
but all ethics, and all religion, both natural and
revealed. It is accordingly with this very maxim
that Madame du Deffand (in a letter which ri¬
vals anything that the fancy of Moliere has con¬
ceived in his JFemmes Savantes) assails Voltaire
for his imbecility in attempting a reply to an
atheistical book then recently published. In
justice to this celebrated lady, I shall transcribe
part of it in her own words, as a precious and
authentic document of the philosophical tone af¬
fected by the higher orders in France, during
the reign of Louis XV.
“ J’entends parler d’une refutation d’un cer¬
tain livre f Systeme de la Nature). Je voudrois
TaVoir. Je m’en tiens a connoitre ce livre par
vous. Toutes refutations de systeme doivent
etre bonnes, surtout quand c’est vous qui les
faites. Mais, mon cher Voltaire, ne vous en-
nuyez-vous pas de tons les raisonnemens meta-
physiques sur les matieres inintelligibles. Peut-
on donner des idees, ou peut-on en admettre d'autres
que cedes que nous recevons par nos sens ?”—If
the Senses be the beginning and end of all our
knowledge, the inference here pointed at is
quite irresistible.2
A learned and profound writer has lately
complained of the injustice done by the present
age to Gassendi; in whose works, he asserts,
may he found the whole of the doctrine com¬
monly ascribed to Locke concerning the origin
of our knowledge.5 The remark is certainly
just, if restricted to Locke’s doctrine as inter¬
preted by the greater part of philosophers on
the Continent; hut it is very wide of the truth,
if applied to it as now explained and modified
by the most intelligent of his disciples in this
country. The main scope, indeed, of Gassendi’s
argument against Descartes, is to materialise
that class of our ideas which the Lockists as
well as the Cartesians consider as the exclusive
objects of the power of reflection ; and to show
that these ideas are all ultimately resolvable into
images or conceptions borrowed from things ex¬
ternal. It is not, therefore, what is sound and
valuable in this part of Locke’s system, hut the
errors grafted on it in the comments of some of
his followers, that can justly he said to have
been borrowed from Gassendi. Nor has Gassendi
the merit of originality, even in these errors ;
for scarcely a remark on the subject occurs in
his works, hut what is copied from the accounts
biere. “ Thomas Hobbius Gassendo charissimus, cujus libellum 'De Corpore paucis ante obitum mensibus accipiens, oscu-
latus est, subjungens, mole quidem parvus est iste liber, verum lotus, ut opinor, medulla scatet!"—(Sorberii Prep.) Gassendi’s
admiration of Hobbes’ Treatise De Give, was equally warm ; as we learn from a letter of his to Sorbiere, prefixed to that
work.
1 Compare Gassendi Opera, Tom. III. p. 300, 301; and Tom. Y. p. 12-
2 Notwithstanding the evidence (according to my judgment) of this conclusion, I trust it will not be supposed that I im¬
pute the slightest bias in its favour to the generality of those who have adopted the premises. If an author is to be held
chargeable with all the consequences logically deducible from his opinions, who can hope to escape censure ? And, in the
present instance, how few are there among Montaigne’s disciples, who have ever reflected for a moment on the real mean¬
ing and import of the proverbial maxim in question !
* Gassendi fut le premier auteur de la nouvelle philosophie de I’esprit humain ; car il est terns de lui rendre, h cet egard,
une justice qu’il n’a presque jamais obtenue de ses propres compatriotes. II est tres singulier en effet, qu’en parlant de
la nouvelle philosophie de I’esprit humain, nous disions toujours, la philosophie de Locke. D’Alembert et Condillac out au-
tonse cette expression, en rapportant 1’un et 1’autre a Locke exclusivement la gloire de cette invention, &c. &c.—Dege-
kando, Hist. Comp, des Systemes, Tome I. p. 30L
DISSERTATION FIRST.
73
transmitted to us of the Epicurean metaphy¬
sics.
Unfortunately for Descartes, while he so clear¬
ly perceived that the origin of those ideas which
are the most interesting to human happiness,
could not he traced to our external senses, he
had the weakness, instead of stating this funda¬
mental proposition in plain and precise terms,
to attempt an explanation of it by the extrava¬
gant hypothesis of innate ideas. This hypothesis
gave Gassendi great advantages over him, in the
management of their controversy; while the
subsequent adoption of Gassendi’s reasonings
against it by Locke, has led to a very general
but ill-founded belief, that the latter, as well as
the former, rejected, along with the doctrine of
innate ideas, the various important and well-
ascertained truths combined with it in the Car¬
tesian system.1
The hypothetical language afterwards intro¬
duced by Leibnitz concerning the human soul
(which he sometimes calls a living mirror of the
universe, and sometimes supposes to contain
within itself the seeds of that knowledge which
is gradually unfolded in the progressive exercise
of its faculties), is another impotent attempt to
explain a mystery unfathomable by human rea¬
son. The same remark may be extended to
some of Plato’s reveries on this question, more
particularly to his supposition, that those ideas
which cannot be traced to any of our external
senses, were acquired by the soul in its state of
pre-existence. In all of these theories, as well
as in that of Descartes, the cardinal truth is as¬
sumed as indisputable, that the Senses are not
the only sources of human knowledge; nor is
any thing wanting to render them correctly lo¬
gical, but the statement of this truth as an ulti¬
mate fact {or at least as a fact hitherto unex¬
plained) in our intellectual frame.
It is very justly observed by Mr Hume, with
respect to Sir Isaac Newton, that “ while he
seemed to draw off the veil from some of the
mysteries of nature, he showed, at the same
time, the imperfections of the mechanical philo¬
sophy, and thereby restored her ultimate secrets
to that obscurity in which they ever did, and
ever will remain.”* When the justness of this
remark shall be as universally acknowledged in
the science of Mind as it now is in Natural Phi¬
losophy, we may reasonably expect that an end
will be put to those idle controversies which
have so long diverted the attention of metaphy¬
sicians from the proper objects of their studies.
The text of Scripture, prefixed by Dr Reid as
a motto to his Inquiry, conveys, in a few words,
the result of his own modest and truly philoso¬
phical speculations on the origin of our know¬
ledge, and expresses this result in terms strictly
analogous to those in which Newton speaks of
the law of gravitation :—“ The inspiration of the
Almighty hath given them under standing.Let
our researches concerning the developement
of Mind, and the occasions on which its various
notions are first formed, be carried back ever so
far towards the commencement of its history, in
this humble confession of human ignorance they
must terminate at last.
I have dwelt thus long on the writings of
Gassendi, much less from my own idea of their
merits, than out of respect to an author, in
whose footsteps Locke has frequently conde¬
scended to tread. The epigrammatic encomium
bestowed on him by Gibbon, who calls him,
“ le meilleur philosophe des litterateurs, et le
meilleur litterateur des philosophes,” appears to
me quite extravagant.3 His learning, indeed,
was at once vast and accurate; and, as a philo¬
sopher he is justly entitled to the praise of being
one of the first who entered thoroughly into the
spirit of the Baconian logic. But his inventive
powers, which were probably not of the highest
order, seem to have been either dissipated amidst
the multiplicity of his literary pursuits, or laid
asleep by his indefatigable labours as a com¬
mentator and a compiler. From a writer of
this class, new lights were not to be expected
in the study of the human Mind; and accord¬
ingly, here he has done little or nothing, but to
revive and to repeat' over the doctrines of the
old Epicureans. His works amount to six
large volumes in folio; but the substance of
* Essai sur VEtude de (a Litterature.
a
1 See Note Q.
DISS. I. PART I.
2 Iflstory of Great Britain, chap. Ixxi.
74
PRELIMINARY DISSERTATIONS.
them might he compressed into a much smaller
compass, without any diminution of their value.
In me respect Gassendi had certainly a great
advantage over his antagonist,—the good humour
which never forsook him in the heat of a philoso¬
phical argument. The comparative indifference
with which he regarded most of the points at
issue between them, was perhaps the chief cause
of that command of temper so uniformly dis¬
played in all his controversies, and so remarkably
contrasted with the constitutional irritability of
Descartes. Even the faith of Gassendi in his
own favourite master, Epicurus, does not seem
to have been very strong or dogmatical, if it be
true that he was accustomed to allege, as the
chief ground of his preferring the Epicurean
physics to the theory of the Vortices, “ that
chimera for chimera, he could not help feeling
some partiality for that which was two thousand
years older than the other.”1
About twenty years after the death of Gassendi
(who did not long survive Descartes), Male-
branche entered upon his philosophical career.
The earlier part of his life had, by the advice of
some of his preceptors, been devoted to the
study of ecclesiastical history, and of the learn¬
ed languages ; for neither of which pursuits does
he seem to have felt that marked predilection
which afforded any promise of future eminence.
At length, in the twenty-fifth year of his age,
he accidentally met with Descartes’ Tfeatise on
Man, which opened to him at once a new world,
and awakened him to a consciousness of powers,
till then unsuspected either by himself or by
others. Fontenelle has given a lively picture of
the enthusiastic ardour with which Malebranche
first read this performance; and describes its
effects on his nervous system as sometimes so
great, that he was forced to lay aside the book
till the palpitation of his heart had subsided.
It was only ten years after this occurrence
when he published The Search after Truth; a
work which, whatever judgment may now be
passed on its philosophical merits, will always
form an interesting study to readers of taste, and
a useful one to students of human nature. Few
books can be mentioned, combining, in so great
a degree, the utmost depth and abstraction of
thought, with the most pleasing sallies of imagi¬
nation and eloquence; and none, where they
who delight in the observation of intellectual
character may find more ample illustrations,
both of the strength and weakness of the human
understanding. It is a singular feature in the
history of Malebranche, that, notwithstanding the
poetical colouring which adds so much animation
and grace to his style, he never could read,
without disgust, a page of the finest verses;2 3 *
and that, although Imagination was manifestly
the predominant ingredient in the composition
of his own genius, the most elaborate passages
in his works are those where he inveighs against
this treacherous faculty, as the prolific parent ot
our most fatal delusions.5
In addition to the errors, more or less incident
to all men, from the unresisted sway of imagina¬
tion during the infancy of reason, Malebranche
had, in his own case, to struggle with all the
prejudices connected with the peculiar dogmas
of the Roman Catholic faith. - Unfortunately,
too, he everywhere discovers a strong disposi¬
tion to blend his theology and his metaphysics
together ; availing himself of the one as an auxi¬
liary to the other, wherever in either science
his ingenuity fails him in establishing a favourite
conclusion. To this cause is chiefly to be as¬
cribed the little attention now paid to a writer
formerly so universally admired, and, in point
of fact, the indisputable author of some of the
most refined speculations claimed by the theo¬
rists of the eighteenth century. As for those
mystical controversies about Grace with An¬
thony Arnauld, on which he wasted so much of
1 See Note R.
2 Bayle—Fontenelle—D’Alembert.
3 In one of his arguments on this head, Malebranche refers to the remarks previously made on the same subject by an
English philosopher, who, like himself, has more than once taken occasion, while warning his readers against the undue in-
fluence of imagination over the judgment, to exemplify the boundless fertility and originality of his own. The following
allusion of Bacon’s, quoted by Malebranche, is eminently apposite and happy:—“ Omnes perceptiones tam sensus quam
mentis sunt ex analogia hominis, non ex analogia universi: Estque intellectus humanus instar speculi inaequalis ad radios
rerum, qui suam naturam naturae rerum immiscet, eamque distorquet et inficit.
DISSERTATION FIRST.
75
his genius, they have long sunk into utter obli¬
vion ; nor should I have here revived the recol¬
lection of them, were it not for the authentic
record they furnish of the passive bondage in
which, little more than a hundred years ago,
two of the most powerful minds of that memor¬
able period were held by a creed, renounced at
the Reformation by all the Protestant countries
of Europe, and the fruitful source, wherever it
has been retained, of other prejudices, not less
to be lamented, of an opposite description.1
When Malebranche touches on questions not
positively decided by the church, he exhibits a
remarkable boldness and freedom of inquiry;
setting at nought those human authorities which
have so much weight with men of unenlighten¬
ed erudition; and sturdily opposing his own
reason to the most inveterate prejudices of his
age. His disbelief in the reality of sorcery,
which, although cautiously expressed, seems to
have been complete, affords a decisive proof of
the soundness of his judgment, where he con¬
ceived himself to have any latitude in exercising
it. The following sentences contain more good
sense on the subject, than I recollect in any
contemporary author. I shall quote them, as
well as the other passages I may afterwards ex¬
tract from his writings, in his own words, to
which it is seldom possible to do justice in an
English version.
“ Les hommes meme les plus sages se con-
duisent plutot par rimagination des autres, je
veux dire par I’opinion et par la coutume, que
par les regies de la raison. Ainsi dans les lieux
ou 1’on brule les sorciers, on ne voit autre chose,
parce que dans les lieux ou 1’on les condamne au
feu, on croit veritablement qu’ils le sont, et cette
croyance se fortifie par les discours qu’on en
tient. Que Ton cesse de les punir, et qu’on les
traite comme des fous, et 1’on verra qu’avec le
terns ils ne seront plus sorciers; parce que ceux
qui ne le sont que par imagination, qui font
certainement le plus grand nombre, deviendront
comme les autres hommes.
“ C’est done avec raison que plusieurs Parle-
mens ne punissent point les sorciers: ils s’en
trouve beaucoup moins dans les terres de leur
ressort: Et 1’envie, et la malice des medians ne
peuvent se servir de ce pretexte pour accabler
les innocens.”
How strikingly has the sagacity of these an¬
ticipations and reflections been verified, by the
subsequent history of this popular superstition
in our own country, and indeed in every other
instance where the experiment recommended by
Malebranche has been tried ! Of this sagacity
much must, no doubt, be ascribed to the native
vigour of a mind struggling against and control¬
ling early prejudices; but it must not be for¬
gotten, that, notwithstanding his retired and
monastic life, Malebranche had breathed the
same air with the associates and friends of Des¬
cartes and of Gassendi ; and that no philosopher
seems ever to have been more deeply impressed
with the truth of that golden maxim of Mon¬
taigne—“ II est bon de frotter et limer notre
cervelle contre eelle d’autrui.”
Another feature in the intellectual character
of Malebranche, presenting an unexpected con¬
trast to his powers of abstract meditation, is the
attentive and discriminating eye with which he
appears to have surveyed the habits and man¬
ners of the comparatively little circlcr around
him; and the delicate yet expressive touches
with which he has marked and defined some of
the nicest shades and varieties of genius.2 To
this branch of the Philosophy of Mind, not cer¬
tainly the least important and interesting, he
i • !a!1S ^lsPosl.tlon to blend theological dogmas with philosophical discussions, Malebranche was so little conscious m
mmselt, that he senously warned his readers against it, by quoting an aphorism of Bacon’s, peculiarly applicable to his own
n mgs. x divinorum et humanorum malesana admixtione non solum educitur philosophiaphantastica, sed etiam reli-
gxo hseretica. Itaque salutare admodum est si mente sobria fidei tantum dentur quse fidei sunt.” In transcribing these
words, it is amusing to observe, that Malebranche has slily suppressed the name of the author from whom they are bor¬
rowed ; manifestly from an unwillingness to weaken their effect, by the suspicious authority of a philosopher not in com-
munion with the Church of Home.—Recherche de la Verite, Liv. ii. chap. ix.
Dr Reid, proceeding on the supposition that Malebranche was a Jesuit, has ascribed to the antipathy between this order
and the Jansemsts, the warmth displayed on both sides, in his disputes with Arnauld (Essays on the Intell. Powers,?. 124.):
u e act is, that Malebranche belonged to the Congregation of the Oratory; a society much more nearly allied to the
--than to the Jesuits; and honourably distinguished, since its first origin, by the moderation as well as learning
See, among other passages, Recherche de la Verite, Liv. ii. chap, ix
76
PRELIMINARY DISSERTATIONS.
has contributed a greater number of original re¬
marks than Locke himself;1 since whose time,
with the single exception of Helvetius, hardly
any attention has been paid to it, either by
French or English metaphysicians. The same
practical knowledge of the human understand¬
ing, modified and diversified, as we everywhere
see it, by education and external circumstances,
is occasionally discovered by his very able anta¬
gonist Arnauld; affording, in both cases, a sa¬
tisfactory proof, that the narrowest field of ex¬
perience may disclose to a superior mind those
refined and comprehensive results, which com¬
mon observers are forced to collect from an ex¬
tensive and varied commerce with the world.
In some of Malebranche’s incidental strictures
on men and manners, there is a lightness of
style and fineness of tact, which one would
scarcely have expected from the mystical divine,
who believed that he saw all things in God.
Who would suppose that the following para¬
graph forms part of a profound argument on
the influence of the external senses over the hu¬
man intellect ?
“ Si, par exemple, celui qui parle s’enonce
avec facilite, s’il garde une mesure agreable dans
ses periodes, s’il a 1’air d’un honnete homme et
d’un homme d’esprit, si c’est une personne de
qualite, s’il est suivi d’un grand train, s’il parle
avec autorite et avec gravite, si les autres
1’ecoutent avec respect et in silence, s’il a
quelque reputation, et quelque commerce avec
les esprits du premier ordre, enfin, s’il est assez
heureux pour plaire, ou pour etre estime, il aura
raison dans tout ce qu’il avancera; et il n’y
aura pas jusqu’a son collet et a ses manchettes,
qui ne prouvent quelque chose.”2
In his philosophical capacity, Malebranche is
i In one of Locke’s most noted remarks of this sort, he has been anticipated by Malebranche, on whose clear
vet concise statement he does not seem to have thrown much new light by his very diffuse and wordy commentary.
esprits7 Les autres Saginent et supposent de la ressemblance entr’elles, et ce sont les esprits superficielsrfe /a
^At\ ^till1 earlier^ period,^ Bacon ^had pointed out the same cardinal distinction in the intellectual characters of
int‘VMax!mUm et velut radicale discrimen ingeniorura, quoad philosophiam et scientias, illud est; quod alia ingema suit
fortiora et aptiora ad notandas rerum differentias ; alia, ad notandas rerum similitudmes. Ingenia emm constantia et acuta,
cSSones, e? morari, et terete it, onrni subtilitate P—itm tasteS
cursiva, etiam tenuissimas et catholicas rerum similitndmes et cognoscunt, et componunt. Utrumque autem ge
facile labitur in excessum, prensando aut gradus rerum, aut umbtas. ;n u<5 most o-eneral form the very
mat strain I heard was of a higher mood ! It is evident, that Bacon has here se^d, in
important truth perceived by his two ingenious successors in pai ticular cas . , indeed a talent very "subor-
is only one of the various talents connected with what Bacon calls the discursive genius, and indeed, a talent very
Maldwandie*
extract it contains from an English publication long since forgotten in this countiy , I y P
ed and pious father was not altogether insensible to the ludicrous. ,. . , I’TTnhrm-^f-d d’Oxford *
“ Un illustre entre les SSavans, quia fonde des chaires de GeWtrie et d’Astronomie dans 1 Umvers td ^
commence un livre, qu’il s’est avise de faire sur les huit premieres propositions d Euc i e’ Pa J . „ Jovositiones vrimi libri
auditores, si vires et valetudo suffecerint, cxplicare dejinitioncs, petitiones, communes senten tas, p r-
Elementorum, ccetera post me venientibus relinquere: et il lefinit par celles-ci: Exsolvi per Dei
missum, liberavi fidem meant, explicavi pro modulo meo dejinitioncs, petitiones, communes sen ’ P ^ corpore et vivido
mentorum Euclidis. Hie annis fessus cyclos artemque repono. Succedent m hoc munus aln f g ^ , Ti .-t <
Zgmio. Il ne faut pas une heure 1, ,4 esprit mediocre, pour apprendre par lui-m me, ou pr e secours du
metrie qu’il y ait, les definitions, demandes, axiomes, et les huit premieres propositions d Eu • .
parle de cette entrepnse, comme de quelque chose de fort grand et de fort difficile. Il a peur que les forces lui ^anquent:
Si vires et valetudo suffecerint. Il laisse a ses successeurs a pousser ce_s choses : coeteraposi me venientibus , elinquere. Jliemerce
Dieu de ce que, par une grace particuliere, il a execute ce qu’il avoit promis : exsolvi per Dei gratiampronussinn, ^ ,
mZi exZicav*pro modulo meo} Quoi P la’quadrature ducercle? la duplication du cube ? Ce grande homme a exphqud
Z fes definitions, les demandes^les axiomes, et les huit premieres propositions du premier livie des
« Sir Henry Savile. The work here referred to is a 4to volume, entitled, Prelectiones xiii. in Principium Elementorum
Euclidis, Oxonice habitce, anno 1620.
DISSERTATION FIRST.
to be considered in two points of view: 1. As a
commentator on Descartes; and, 2. As the
author of some conclusions from the Cartesian
principles, not perceived or not avowed by his
predecessors of the same school.
1. I have already taken notice of Malebranche’s
comments on the Cartesian doctrine concerning
the sensible, or, as they are now more commonly
called, the secondary qualities of matter. The
same fulness and happiness of illustration are
everywhere else to he found in his elucidations
of his master’s system ; to the popularity of which
he certainly contributed greatly by the liveliness
of his fancy, and the charms of his composition.
Even in this part of his writings, he always pre¬
serves the air of an original thinker; and, while
pursuing the same path with Descartes, seems
rather to have accidentally struck into it from
his own casual choice, than to have selected it
out of any deference for the judgment of another.
Perhaps it may he doubted, if it is not on such
occasions that the inventive powers of his genius,
by being somewhat restrained and guided in
their aim, are most vigorously and most useful¬
ly displayed.
In confirmation of this last remark, I shall
77
only mention, by way of examples, his com¬
ments on the Cartesian theory of Vision,—more
especially on that part of it which relates to our
experimental estimates of the distances and
magnitudes of objects; and his admirable illus¬
tration of the errors to which we are liable from
the illusions of sense, of imagination, and of the
passions. In his physiological reveries on the
union of soul and body, he wanders, like his
master, in the dark, from the total want of facts
as a foundation for his reasonings; hut even
here his genius has had no inconsiderable in¬
fluence on the inquiries of later writers. The
fundamental principle of Hartley is most expli¬
citly stated in The Search after Truth ;1 as well
as a hypothesis concerning the nature of habits,
which, rash and unwarranted as it must now
appear to every novice in science, was not
thought unworthy of adoption in The Essay on
Human Understanding.2
2. Among the opinions which chiefly charac¬
terise the system of Malehranche, the leading
one is, that the causes which it is the aim of
philosophy to investigate are only occasional
causes; and that the Deity is himself the effi¬
cient and immediate cause of every effect in the
d’Euclide. Peut-ctre qu’entre ceux qui lui succederont, il s’en trouvera qui auront plus de santd, et plus de force que lui
pour continuer ce bel ouvrage: Succedent in hoc munus alii fortasse magis vegeto corpore et vivido ingenio. Mais pour lui
il est terns qu’il se repose; hie annis fessus cyclos artemque repono."
After reading the above passage, it is impossible to avoid reflecting, with satisfaction, on the effect which the progress of
philosophy has since had, in removing those obstacles to the acquisition of useful knowledge, which were created by the
pedantic taste prevalent two centuries ago. What a contrast to a quarto commentary on the definitions, postulates, axioms,
and first eight propositions of Euclid’s First Book, is presented by Condorcet’s estimate of the time now sufficient to con¬
duct a student to the highest branches of Mathematics ! “ Dans le siecle dernier, il suffisoit de quelques anndes d’e'tude
pour savoir tout ce qu’Archimede et Hipparque avoient pu connoitre ; et aujourd’hui deux annees de I’enseignement
d’un professeur vont au dela de ce que savoient Leibnitz ou Newton.”—(Sur l'Instruction Publique.) In this particular
science, I am aware that much is to be ascribed to the subsequent invention of new and more general methods; but,
I apprehend, not a little also to the improvements gradually suggested by experience, in what Bacon calls the traditive part
of logic.
1 “ Toutes nos differentes perceptions sont attachees aux differens changemens qui arrivent dans les fibres de la partie
principale du cerveau dans laquelle Tame reside plus particulierement.”—(Rech. de la Verite, Liv, ii. chap, v.) These
changes in the fibres of the brain are commonly called by Malebranche ebranlemens;—a word which is frequently rendered
by his old English translator (Taylor) vibrations. “ La seconde chose,” says Malebranche, “ qui se trouve dans chacune
des sensations, est Vebranlement des fibres de nos nerfs, qui se communique jusqu’au cerveau thus translated by Taylor:
“ The second thing that occurs in every sensation is the vibration of the fibres of our nerves, which is communicated to the
brain.”—Liv. i. chap, xii.) Nor was the theory of association overlooked by Malebranche. See, in particular, the third
chapter of his second book, entitled, De la liaison mutuelle des idecs de Vesprit, et des traces du cerveau ; et de la, liaison mutuelle
des traces avec les traces, et des idles avec les idles.
- “ Mais afin de suivre notre explication, il faut reniarquer que les esprits ne trouvent pas toujours les chemins, par ou
ils doivent passer assez ouverts et assez fibres : et que cela fait qui nous avons de la difficulte a remuer, par exemple, les
doigts avec la vitesse qui est ndeessaire pour jouer des instrumens de musique, ou les muscles qui servent a la prononciation,
pour prononcer les mots d’une langue etrangere : Mais que peu-a-peu les esprits animaux par leur cours continuel ouvrent et
applanissent ces chemins, eh sortequ’avec le terns ils n’y trouvent plus de resistance. Car e’est dans cette facility que les
esprits animaux ont de passer dans les membres de riotre corps que consistent les habitudes.”—Rech. de la Verite, Liv. ii.
chap. v.
“ Habits seem to be but trains of motion in the animal spirits, which, once set a-going, continue in the same steps they
have been used to, which, by often treading, are worn into a smooth path."—Locke, Book ii. chap, xxxiii. §• C.
78
PRELIMINARY DISSERTATIONS.
universe.1 From this single principle, the greater
part of his distinguishing doctrines may he easily
deduced, as obvious corollaries.
That we are completely ignorant of the man¬
ner in which physical causes and effects are con¬
nected, and that all our knowledge concerning
them amounts merely to a perception of constant
conjunction, had been before remarked by Hobbes,
and more fully shown by Glanville in his Scepsis
Scientijica. Malebranche, however, has treated
the same argument much more profoundly and
ably than any of his predecessors, and has, in¬
deed, anticipated Hume in some of the most in¬
genious reasonings contained in his Essay on
Necessary Connexion. From these data, it was
not unnatural for his pious mind to conclude,
that what are commonly called second causes have
no existence; and that the Divine power, inces¬
santly and universally exerted, is, in truth, the
connecting link of all the phenomena of nature.
It is obvious that, in this conclusion, he went
farther than his premises warranted; for, al¬
though no necessary connections among physical
events can be traced by our faculties, it does not
therefore follow that such connections are im¬
possible. The only sound inference was, that
the laws of nature are to he discovered, not, as
the ancients supposed, by a priori reasonings
from causes to effects, but by experience and ob¬
servation. It is but justice to Malebranche to
own, that he was one of the first who placed in
a just and strong light this fundamental prin¬
ciple of the inductive logic.
On the other hand, the objections to the
theory of occasional causes, chiefly insisted on by
Malehranche’s opponents, were far from satis¬
factory. By some it was alleged, that it ascribed
every event to a miraculous interposition of the
Deity; as if this objection were not directly met
by the general and constant laws everywhere
manifested to our senses,—in a departure from
which laws, the very essence of a miracle con¬
sists. Nor was it more to the purpose to con¬
tend, that the beauty and perfection of the uni¬
verse were degraded by excluding the idea of
mechanism ; the whole of this argument turning,
as is manifest, upon an application to Omnipo¬
tence of ideas borrowed from the limited sphere
of human power.2 As to the study of natural
philosophy, it is plainly not at all affected by the
hypothesis in question • as the investigation and
generalisation of the laws of nature, which are
its only proper objects, present exactly the same
field to our curiosity, whether we suppose these
laws to he the immediate effects of the Divine
agency, or the effects of second causes, placed
beyond the reach of our faculties.3
Such, however, were the chief reasonings op¬
posed to Malebranche by Leibnitz, in order to
prepare the way for the system of Pre-established
Harmony; a system more nearly allied to that
of occasional causes than its author seems to have
suspected, and encumbered with every solid dif¬
ficulty connected with the other.
From the theory of occasional causes, it is easy
to trace the process which led Malebranche to
1 “ Afin qu’on ne puisse plus douter de la faussetd de cette miserable philosophie, il est necessaire de prouver qu’il n’y a
qu’un vrai Dieu, parce qu’il n’y a qu’une vraie cause; que la nature ou la force de chaque chose n’est que la volonte de
Dieu: que toutes les causes naturelles ne sont point des veritables causes, mais seulement des causes occasionelles—Be la
Vtrite, Livre vi. 2de Partie, chap. iii.
2 This objection, frivolous as it is, was strongly urged by Mr Boyle (Inquiry into the Vulgar Idea concerning Nature), and
has been copied from him by Mr Hume, Lord Kaimes, and many other writers. Mr Hume’s words are these:—“ It ar¬
gues more wisdom to contrive at first the fabric of the world with such perfect foresight, that, of itself, and by its proper
operation, it may serve all the purposes of Providence, than if the great Creator were obliged every moment to adjust its
parts, and animate by his breath all the wheels of that stupendous machine.''—Essay on the Idea of Necessary Connection.) An
observation somewhat similar occurs in the Treatise De Mundo, commonly ascribed to Aristotle.
3 In speaking of the theory of occasional causes, Mr Hume has committed a historical mistake, which it may be proper to
rectify. “ Malebranche,” he observes, and other Cartesians, made the doctrine of the universal and sole efficacy of the
Deity, the foundation of all their philosophy. It had, however, no authority in England. Locke, Clarke, and Cudworth,
never so much as take notice of it, but suppose all along that matter has a real, though subordinate and derived power.”—
Hume's Essays, Vol. II. p. 475. Edit, of 1784.
Mr Hume was probably led to connect, in this last sentence, the name of Clarke with those of Locke and Cudworth, by
taking for granted that his metaphysical opinions agreed exactly with those commonly ascribed to Sir Isaac Newton. In
fact, on the point now in question, his creed was the same with that of Malebranche. The following sentence is very
nearly a translation of a passage already quoted from the latter. “ The course of nature, truly and properly speaking, is
nothing but the will of God producing certain effects in a continued, regular, constant, and uniform manner.”—Clarke’s
Works Vol. II. p. 698. Fob Ed.
DISSERTATION FIRST.
79
conclude, that we see all things in God. The
same arguments which convinced him, that the
Deity carries into execution every volition of the
mind, in the movements of the body, could not
fail to suggest, as a farther consequence, that
every perception of the mind is the immediate
effect of the divine illumination. As to the
manner in which this illumination is accom¬
plished, the extraordinary hypothesis adopted
by Malebranche was forced upon him, by the
opinion then universally held, that the imme¬
diate objects of our perceptions are not things
external, but their ideas or images. The only
possible expedient for reconciling these two ar¬
ticles of his creed, was to transfer the seat of
our ideas from our own minds to that of the
Creator.1
In this theory of Malebranche, there is un¬
doubtedly, as Bayle has remarked,2 an approach
to some speculations of the latter Platonists;
but there is a much closer coincidence between
it and the system of those Hindoo philosophers,
who, according to Sir William Jones, “ believed
that the whole creation was rather an energy
than a work; by which the Infinite Mind, who
is present at all times, and in all places, exhibits
to his creatures a set of perceptions, like a won¬
derful picture, or piece of music, always varied,
yet always uniform.”3
In some of Malebranche’s reasonings upon this
subject, he has struck into the same train of
thought which was afterwards pursued by Berke-
ley, an author to whom he bore a very strong
resemblance in some of the most characteristical
features of his genius; and, had he not been
restrained by religious scruples, he would, in all
probability, have asserted, not less confidently
than his successor, that the existence of matter
was demonstrably inconsistent with the prin¬
ciples then universally admitted by philosophers.
But this conclusion Malebranche rejects, as not
reconcileable with the words of Scripture, that
“ in the beginning God created the heavens and
the earth.” “ La foi m’apprend que Dieu a
cree le ciel et la terre. Elle m’apprend que
1 Ecriture est un livre divin. Et ce livre ou son
apparence me dit nettement et positive men t,
qu il y a mille et mille creatures. Done voila
toutes mes apparences changees en realites. II
y a des corps; cela est demontr6 en toute ri-
gueur la foy supposee.”4
In reflecting on the repeated reproduction of
these, and other ancient paradoxes, by modern
authors, whom it would be highly unjust to ac¬
cuse of plagiarism;—-still more, in reflecting on
the affinity of some of our most refined theories
to the popular belief in a remote quarter of the
globe, one is almost tempted to suppose, that
human invention is limited, like a barrel-organ,
t° a specific number of tunes. But is it not a
fairer inference, that the province of pure Ima¬
gination, unbounded as it may at first appear, is
narrow, when compared with the regions open¬
ed by truth and nature to our powers of observa¬
tion and reasoning?5 Prior to the time of Bacon,
the physical systems of the learned performed
their periodical revolutions in orbits as small as
the metaphysical hypotheses of their successors;
and yet, who would now set any bounds to our
curiosity in the study of the material universe ?
Is it reasonable to tbink, that the phenomena of
the intellectual world are less various, or less
marke^with the signatures of Divine wisdom ?
It forms an interesting circumstance in the
history of the two memorable persons who have
suggested these remarks, that they had once,
on tfS^eTe^attjhvDo^is11^^?1’ ^ P^f v,ation «f an, epigrammatic line (un vers fort plaisant, as he justly calls it),
“ un fou qui avcdt^b^uicmip8 d’esprit.*” *“* ™ ^ ^ MpaS *U'il estfou -'-C’etoit au moinsLa Harpe adds,
4 See his Dictionary, article Amelins.
Introduction to a Translation of some Hindoo verses.
* Entretiens sur la Metaphysique, p. 207.
nP^o^Celeb?vted °f Descartes concerning all truths but the existence of his own mind fit cannot be too often re
L^ afte^rds1 sterteTbv Rerice?17 °f^ W inconsi„s,tenc3[ of Malebranche on this head, but of the chief metaphysical
prindnle to other Sntbf wL f ^ 7 The J loglcal transition by which he attempted to pass from this first
man^anhavefulfas^nranVrof !1n^fih,renifrtCeci.b^ S°m-e ^ °wn .folloWers’ who were accordingly led to conclude, that no
ted as reason ab Ip tbp prmnl • U °}vniI1<?iy'1^ua^exi®teince.> If the fundamental doubt of Descartes be admit-
5 The limited numhpr nf /hf1 ° f P ll osoPhers (who were distinguished by the name of Egoists), is unavoidable.
face of the s-lohe imVlu np if eSi of hunlorous tales, mid even of jests, which, it should seem, are in circulation over the
race or the globe, might perhaps be alleged as an additional confirmation of this idea.
80
PRELIMINARY DISSERTATIONS.
and only o/ice, the pleasure of a short interview.
“ The conversation,” we are told, “ turned on
the non-existence of matter. Malebianche,
who had an inflammation in his lungs, and whom
Berkeley found preparing a medicine in his cell,
and cooking it in a small pipkin, exerted his
voice so violently in the heat of their dispute,
that he increased his disorder, which carried
him off a few days after.”1 It is impossible not
to regret, that of this interview there is no other
recordor rather, that Berkeley had not made
it the groundwork of one of his own dialogues.
Fine as his imagination was, it could scarcely
have added to the picturesque effect of the real
scene.2
Anthony Arnauld, whom I have already men¬
tioned as one of the theological antagonists of
Malehranche, is also entitled to a distinguished
rank among the French philosophers of this
period. In his book on true and false ideas, writ¬
ten in opposition to Malebranche’s scheme of
our seeing all things in God, he is acknowledg¬
ed by Dr Reid to have struck the first mortal
blow at the ideal theory ; and to have appioxi-
mated very nearly to his own refutation of this
ancient and inveterate prejudice.3 A step so
important would, of itself, be sufficient to esta¬
blish his claim to a place in literary history ; but
what chiefly induces me again to bring forward
his name, is the reputation he has so justly ac¬
quired by his treatise, entitled, The Art of
Thinking ;4 a treatise written by Arnauld, in
conjunction with his friend Nicole, and of which
(considering the time when it appeared) it is
hardly possible to estimate the merits too highly.
No publication, certainly, prior to Locke’s Essay,
can be named, containing so much good sense,
and so little nonsense on the science of Logic ;
and very few have since appeared on the same
subject, which can be justly preferred to it, in
point of practical utility. If the author had
lived in the present age, or had been less fetter¬
ed by a prudent regard to existing prejudices,
the technical part would probably have been re¬
duced within a still narrower compass ; but even
there, he has contrived to substitute for the
puerile and contemptible examples of common
logicians, several interesting illustrations from
the physical discoveries of his immediate pre-
^ Thfs interview happenedin 1715, when Berkeley was in the thirty-first, and Malebranche in the seventy-seventh
year of his age. What a change in the state of the philosophical world (whether for the better or worse is a difteren
Question') has taken place in the course of the intervening century ! •*. r* 4.r.* i • .£»
q Dr Warburton, who, even when he thinks the most unsoundly, always possesses the rare merit of thinking for himself,
is one of the ver^ few English authors who have spoken of Malebranche with the respect due to his extraordinary talents
“ AlWousayof Malebranche,” he observes in a letter to Dr Hurd, “ is strictly true ; he is an admirable writer. There
is somethin/very different in the fortune of Malebranche and Locke. When Malebranche first appeared, it was with a
general apnLse and admiration ; when Locke first published his Essay, he had hardly a single^ approver. Now Locke
fsSersTrd Malebranche silnk into obscurity. All this maybe easily accounted for. The intrinsic merit of either
was out of the question. But Malebranche supported his first appearance on a philosophy in the highest vogue , that phi-
losophy has been^verturned by the Newtonian, and Malebranche has fallen with his master. It was to no purpose to
tell the world, that Malebranche could stand without him. The public never examines so narrowly. Not but that
there was another cause sufficient to do the business ; and that is, his debasing Ins noble work with his ^stein °^seei^^
things in God. When this happens to a great author, one half of his readers out of folly, the other out of malice, d veil
only on the unsound part, and forget the other, or use all their arts to have it forgotten. , , ri-0v,riTlfllir n^mself bv
“But the sage Locke supported himself by no system on the one hand; nor, on the other, did he dishonour himself by
any whimsies. The consequence of which was, that, neither following the fashion, nor str^mg the imagination, he, at
first, had neither followers nor admirers; but being everywhere clear, and everywhere solid, he at length worked his way
and afterwards was subject to no reverses. He was not affected by the new fashions in philosophy, who leaned upon none
of the old ; nor did he afford ground for the after-attacks of envy and folly by any fanciful hypotheses, which, when grown
stale, are the most nauseous of all things.” ,
The foregoing reflections on the opposite fates of these two philosophers, do honour on the who «
tration ; but the unqualified panegyric on Locke will be now very generally allowed to furnish an additional example of
“ that national spirit? which,” according to Hume, “ forms the great happiness of the English, and pleads them to bestow
on all their eminent writers such praises and acclamations, as may often appear partial and exceasive. u
3 The following very concise and accurate summary of Arnauld’s doctrine concerning ideas, is given by rue -er.
tonius Arnaldus, ut argumenta Malebranchii eo fortius everteret, peculiarem sententiam detendit, asseruitque, ideas earum-
nue nerceptiones esse unum idemque, et non nisi relationibus differre. Ideam scilicet esse, quatenus ad objectum refertur
quod mens considerat; perceptionem vero, quatenus ad ipsam mentem quae percipit; dupheem tamen illam relatione
unam pertinere mentis modificationem.”-^. Phil, de Jdeis, pp. 247. 248. Anthony Arnauld farther held that “ Mate¬
rial things are perceived immediately by the mind, without the intervention of ideas. —{Hist, de Ideis, p. 26.) In Hus e.
spect his°doctrine coincided exactly with that of Reid.
-1 More commonly known by the name of the Port-Royal Logic.
*
DISSERTATION FIRST.
81
dceessors: and has indulged himself in some
short excursions, which excite a lively regret
that he had not, more frequently and freely,
given scope to his original reflections. Among
these excursions, the most valuable, in my opi¬
nion, is the twentieth chapter of the third part,
which deserves the attention of every logical
student, as an important and instructive supple¬
ment to the enumeration of sophisms given by
Aristotle.1 2
The soundness of judgment, so eminently
displayed in the Art of Thinking, forms a curi¬
ous contrast to that passion for theological con¬
troversy, and that zeal for what he conceived
to be the purity of the Faith, which seems to
have been the ruling passions of the author’s
mind. He lived to the age of eighty-three, con¬
tinuing to write against Malebranche’s opinions
concerning Nature and Grace, to his last hour.
“ He died,” says his biographer, <{ in an obscure
retreat at Brussels, in 1692, without fortune,
and even without the comfort of a servant.; he,
whose nephew had been a Minister of State,
and who might himself have been a Cardinal.
The pleasure of being able to publish his senti¬
ments, was to him a sufficient recompense.”
Nicole, his friend and companion in arms, worn
out at length with these incessant disputes, ex¬
pressed a wish to retire from the field, and to
enjoy repose. {£ Repose /” replied Arnauld;
“ won’t you have the whole of eternity to re¬
pose in ?”
An anecdote which is told of his infancy,
when considered in connection with his subse¬
quent life, affords a good illustration of the force
of impressions received in the first dawn of
reason. He was amusing himself one day with
some childish sport, in the library of the Cardi¬
nal du Perron, when he requested of the Cardi¬
nal to give him a pen :—C{ And for what pur¬
pose ?” said the Cardinal.—<c To write books, like
you, against the Huguenots.” The Cardinal, it
is added, who was then old and infirm, could not
conceal his joy at the prospect of so hopeful a
successor; and, as he was putting the pen into
his hand, said, <c I give it to you, as the dying
shepherd Damoetas bequeathed his pipe to the
little Corydon.”
The name of Pascal (that prodigy of parts, as
Locke calls him) is more familiar to modern ears
than that of any of the other learned and polish¬
ed anchorites, who have rendered the sanctuary
of Port-Royal so illustrious; but his writings
furnish few materials for philosophical history.
Abstracting from his great merits in mathema¬
tics and in physics, his reputation rests chiefly
on the Provincial Letters; a work from which
Voltaire, notwithstanding his strong prejudices
against the author, dates the fixation of the
French language; and of which the same ex¬
cellent judge has said, that “ Moliere’s best
comedies do not excel them in wit, nor the com¬
positions of Bossuet in sublimity.” The enthu¬
siastic admiration of Gibbon for this book, which
he was accustomed from his youth to read once
a year, is well known, and is sufficient to ac¬
count for the rapture with which it never fails
to be spoken of by the erudite vulgar* in this
country. I cannot help, however, suspecting,
1 According to Crousaz, The Art of Thinking contributed more than either the Organon of Bacon, or the Method of Des¬
cartes, to improve the established modes of academical education on the Continent—(See the Preface to his Logic,
printed at Geneva, 1724.) Leibnitz himself has mentioned it in the most flattering terms; coupling the name of the
author with that of Pascal, a still more illustrious ornament of the Port-Royal Society“ Ingeniosissimus Pascalius in
prseclara dissertatione de ingemo Geometrico, cujus fragmentum extat in egregio hbro celeberrimi viri Antonii Ar-
naldi de Arte bene Cogitandi,” &c..; but lest this encomium from so high an authority should excite a curiosity somewhat
out of proportion to the real value of the two works here mentioned, I think it right to add, that the praises bestowed by
Leibnitz, whether on living or dead authors, are not always to be strictly and literally interpreted. “ No one,” says
Hume, “ is so liable to an excess of admiration as a truly great genius.” Wherever Leibnitz has occasion to refer to any
work of solid merit, this remark applies to him with peculiar force ; partly, it is probable, from his quick and sympathetic
perception of congenial excellence, and partly from a generous anxiety to point it out to the notice of the world. It af¬
fords, on the other hand, a remarkable illustration of the force of prejudice, that Buffler, a learned and most able Jesuit,
should have been so far influenced by the hatred of his order to the Jansenists, as to distinguish the Port-Royal Logic with
the cold approbation of being “ a judicious compilation fiom former works on the same subject,—particularly from a trea¬
tise by a Spanish Jesuit, Fonstca."—Cours de Sciences, p. 873. Paris, 1732. Gibbon also has remarked how much “ the
learned Society of Port-Royal contributed to establish in France a taste for just reasoning, simplicity of style, and philoso¬
phical method.”—Misc. Works, Yol. II. p. 70.
2 Eruditum Vulgus—Plin. Nat. Hist. Lib. ii.
DISS. I. PART 1. L
82
PRELIMINARY DISSERTATIONS.
that it is now more praised than read in Great
Britain; so completely have those disputes, to
which it owed its first celebrity, lost their in¬
terest. Many passages in it, indeed, will al¬
ways he perused with delight; hut it may he
questioned, if Gibhon himself would have read
it so often from beginning to end, had it not
been for the strong hold which ecclesiastical con¬
troversies, and the Roman Catholic faith, had
early taken of his mind.
In one respect, the Provincial Letters are well
entitled to the attention of philosophers; inas¬
much as they present so faithful and lively a
picture of the influence of false religious views
in perverting the moral sentiments of mankind.
The overwhelming ridicule lavished by Pascal on
the whole system of Jesuitical casuistry, and the
happy effects of his pleasantry in preparing,
from a distance, the fall of that formidable
order, might be quoted as proofs, that there are
at least some truths, in whose defence this weapon
may be safely employed;—perhaps with more
advantage than the commanding voice of Reason
herself. The mischievous absurdities which it
was his aim to correct, scarcely admitted of the
gravity of logical discussion; requiring only the
extirpation or the prevention of those early pre¬
judices which choke the growth of common
sense and of conscience : And for this purpose,
what so likely to succeed with the open and ge¬
nerous minds of youth, as Ridicule, managed
with decency and taste; more especially when
seconded, as in the Provincial Letters, by acute¬
ness of argument, and by the powerful eloquence
of the heart ? In this point of view, few practi¬
cal moralists can boast of having rendered a
more important service than Pascal to the gene¬
ral interests of humanity. Were it not, indeed,
for his exquisite satire, we should already be
tempted to doubt, if, at so recent a date, it were
possible for such extravagances to have main¬
tained a dangerous ascendant over the human
understanding.
The unconnected fragment of Pascal, entitled
Thoughts on Religion, contains various reflec¬
tions which are equally just and ingenious;
some which are truly sublime; and not a few
which are false and puerile: the whole, how¬
ever, deeply tinctured with that ascetic and mor¬
bid melancholy, which seems to have at last
produced a partial eclipse of his faculties. Vol¬
taire has animadverted on this fragment with
much levity and petulance; mingling, at the
same time, with many very exceptionable stric¬
tures, several of which it is impossible to dispute
the justness. The following reflection is worthy
of Addison, and bears a strong resemblance in
its spirit to the amiable lessons inculcated in his
papers on Cheerfulness;1 “To consider the
world as a dungeon, and the whole human race
as so many criminals doomed to execution, is
the idea of an enthusiast; to suppose the world
to be a seat of delight, where we are to expect
nothing but pleasure, is the dream of a Sybarite ;
but to conclude that the Earth, Man, and the
lower Animals, are, all of them, subservient to
the purposes of an unerring Providence, is, in
my opinion, the system of a wise and good
man.”
From the sad history of this great and excel¬
lent person (on whose deep superstitious gloom
it is the more painful to dwell, that, by an un¬
accountable, though not singular coincidence,
it was occasionally brightened by the inoffen¬
sive play of a lively and sportive fancy) the eye
turns with pleasure to repose on the mitts sa-
pientta, and the Elysian imagination of Fenelon.
The interval between the deaths of these two
writers is indeed considerable ; but that between
their births does not amount to thirty years;
and, in point of education, both enjoyed nearly
the same advantages.
The reputation of Fenelon as a philosopher
would probably have been higher and more uni¬
versal than it is, if he had not added to the
depth, comprehension, and soundness of his
judgment, so rich a variety of those more pleas¬
ing and attractive qualities, which are common¬
ly regarded rather as the flowers than the fruits
of study. The same remark may be extended
to the Fenelon of England, whose ingenious and
original essays on the Pleasures of Imagination
would have been much more valued by modern
1 Spectator, No. 381 and 387.
DISSERTATION FIRST.
S3
metaphysicians, had they been less beautifully
and happily written. The characteristical ex¬
cellence, however, of the Archbishop of Cam-
bray is, that moral wisdom, which (as Shaftes¬
bury has well observed), <{ comes more from
the heart than from the headand which seems
to depend less on the reach of our reasoning
powers, than on the absence of those narrow
and malignant passions, which, on all questions
of ethics and politics (perhaps I might add of
religion also), are the chief source of our specu¬
lative errors.
The Adventures of Telemachus, when consider¬
ed as a production of the seventeenth centmy,
and still more as the work of a Roman Catholic
Bishop, is a sort of prodigy; and it may, to this
day, be confidently recommended, as the best
manual extant, for impressing on the minds of
youth the leading truths, both of practical mo¬
rals and of political economy. Nor ought it to be
concluded, because these truths appear to lie so
near the surface, and command so immediately
the cordial assent of the understanding, that
they are therefore obvious or trite; for the case
is the same with all the truths most essential to
human happiness. The importance of agricul¬
ture and of religious toleration to the prosperity
of states; the criminal impolicy of thwarting
the kind arrangements of Providence, by re¬
straints upon commerce; and the duty of legis¬
lators to study the laws of the moral world as
the groundwork and standard of their own, ap¬
pear, to minds unsophisticated by inveterate
prejudices, as approaching nearly to the class of
axioms;—yet, how much ingenious and refined
discussion has been employed, even in our own
times, to combat the prejudices which every¬
where continue to struggle against them; and
how remote does the period yet seem, when
there is any probability that these prejudices
shall be completely abandoned !
{C But how,” said Telemachus to Narbal,
“ can such a commerce as this of Tyre be es¬
tablished at Ithaca ?” “ By the same means,”
said Narbal, “ that have established it here.
Receive all strangers with readiness and hospi¬
tality ; let them find convenience and liberty in
your ports; and be careful never to disgust
them by avarice or pride : above all, never re¬
strain the freedom of commerce, by rendering
it subservient to your own immediate gain. The
pecuniary advantages of commerce should be
left wholly to those by whose labour it subsists ;
lest this labour, for want of a sufficient motive,
should cease. There are more than equivalent
advantages of another kind, which must neces¬
sarily result to the Prince from the wealth
which a free commerce will bring into his state;
and commerce is a kind of spring, which to di¬
vert from its natural channel is to lose.”1 Had
the same question been put to Smith or to
Franklin in the present age, what sounder ad¬
vice could they have offered ?
In one of Fenelon’s Dialogues of the Dead, the
following remarkable words are put into the
mouth of Socrates: “ It is necessary that a
people should have written laws, always the
same, and consecrated by the whole nation;
that these laws should be paramount to every
thing else; that those who govern should derive
their authority from them alone; possessing an
unbounded power to do all the good which the
laws prescribe, and restrained from every act of
injustice which the laws prohibit.”
But it is chiefly in a work which did not ap¬
pear till many years after his death, that we
have an opportunity of tracing the enlargement
of Fenelon’s political views, and the extent of
his Christian charity. It is entitled, Direction
pour la Conscience d’un Roi; and abounds with
as liberal and enlightened maxims of govern¬
ment as, under the freest constitutions, have
ever been offered by a subject to a sovereign.
Where the variety of excellence renders selec¬
tion so difficult, I must not venture upon any
extracts; nor, indeed, would I willingly injure
the effect of the whole by quoting detached pas¬
sages. A few sentences on liberty of conscience
(which I will not presume to translate) may
suffice to convey an idea of the general spirit
with which it is animated. <c Sur toute chose,
ne forcez jamais vos sujets a changer de religion.
1 Hawkesworth’s Translation.
84
PRELIMINARY DISSERTATIONS.
Nulle puissance humaine ne pent forcer le re-
tranchement impenetrable de la liberte du coeur.
La force ne pent jamais persuader les hommes;
elle ne fait que des hypocrites. Quand les rois
se melent de religion, au lieu de la proteger, ils
la mettent en servitude. Accordez a tous la to¬
lerance civile, non en approuvant tout comme
indifferent, mais en souffrant avec patience tout
ce que Dieu souffre, et en tachant de ramener
les bommes par une douce persuasion.”
And so much for the French philosophy of
the seventeenth century. The extracts last
quoted forewarn us, that we ar e fast approaching
to a new era in the history of the Human
Mind. The glow-worm ’gins to pale his ineffectual
Jire ; and we scent the morning air of the coming
day. This era I propose to date from the pub¬
lications of Locke and of Leibnitz: but the re¬
marks which I have to offer on their writings,
and on those of their most distinguished suc¬
cessors, I reserve for the Second Part of this
Discourse, confining myself, at present, to a
very short retrospect of the state of philosophy,
during the preceding period, in some other
countries of Europe.1
SECTION HI.
Progress of Philosophy during the Seventeenth Century, in some patls of Europe, not included in the
preceding Review.
During the first half of the seventeenth cen¬
tury, the philosophical spirit which had arisen
with such happy auspices in England and in
France, has left behind it few or no traces of its
existence in the rest of Europe. On all ques¬
tions connected with the science of mind (a phrase
which I here use in its largest acceptation), au¬
thority continued to be everywhere mistaken for
argument; nor can a single work be named,
bearing, in its character, the most distant resem¬
blance to the Organon of Bacon; to the Medita¬
tions of Descartes ; or to the bold theories of
that sublime genius, who, soon after, was to shed
so dazzling a lustre on the north of Germany.
Kepler and Galileo still lived;—the former lan¬
guishing in poverty at Prague; the latter op¬
pressed with blindness, and with ecclesiastical
persecution, at Florence: but their pursuits
were of a nature altogether foreign to our pre¬
sent subject.
One celebrated Work alone, the treatise of
Grotius De Jure Belli et Pads (first printed in
1625), arrests our attention among the crowd
of useless and forgotten volumes, which were
then issuing from the presses of Holland, Ger¬
many, and Italy. The influence of this treatise,
in giving a new direction to the studies of the
learned, was so remarkable, and continued so
long to operate with undiminished effect, that it
is necessary to allot to the author, and to his
successors, a space considerably larger than may,
at first sight, seem due to their merits. Not¬
withstanding the just neglect into which they
have lately fallen in our universities, it will be
found, on a close examination, that they form
an important link in the history of modern lite¬
rature. It was from their school that most of
dur best writers on Ethics have proceeded, and
many of our most original inquirers into the
Human Mind; and it is to the same school (as
1 I have classed Ttltmaque and the Direction pour la Conscience d'un Rot with the philosophy of the seventeenth century,
although the publication of the former was not permitted till after the death of Louis XIV. nor that of the latter till 1748.
The tardy appearance of both only shows how far the author had shot a-head of the orthodox religion and politics of his
times.
DISSERTATION FIRST.
85
I shall endeavour to show in the Second Part of
this Discourse), that we are chiefly indebted for
the modern science of Political Economy.1
For the information of those who have not
read the treatise De Jure Belli et Pads, it may
be proper to observe, that, under this title, Gro-
tius has aimed at a complete system of Natural
Law. Condillac says, that he chose the title, in
order to excite a more general curiosity; add¬
ing (and, I believe, very justly), that many of
the most prominent defects of his works may be
fairly ascribed to a compliance with the taste
of his age. {< The author,” says Condillac,
“ was able to think for himself; but he con¬
stantly labours to support his conclusions by the
authority of others; producing, on many oc¬
casions, in support of the most obvious and in¬
disputable propositions, a long string of quota¬
tions from the Mosaic law; from the Gospels;
from the Fathers of the Church; from the Ca¬
suists; and, not unfrequently, in the very same
paragraph, from Ovid and Aristophanes.” In
consequence of this cloud of witnesses, always
at hand to attest the truth of his axioms, not
only is the attention perpetually interrupted and
distracted; but the author’s reasonings, even
when perfectly solid and satisfactory, fail in
making a due impression on the reader’s mind;
while the very little that there probably was of
systematical arrangement in the general plan of
the hook, is totally kept out of view.
In spite of these defects, or rather, perhaps,
in consequence of some of them, the impression
produced by the treatise in question, on its first
publication, was singularly great. The stores
of erudition displayed in it recommended it to
the classical scholar; while the happy applica¬
tion of the author’s reading to the affairs of hu¬
man life, drew the attention of such men as
Gustavus Adolphus; of his Prime Minister, the
Chancellor Oxenstiern; and of the Elector Pa¬
latine, Charles Lewis. The last of these was so
struck with it, that he founded at Heidelberg a
Professorship for the express purpose of teach¬
ing the Law of Nature and Nations;—an office
which he bestowed on Puffendorff, the most
noted, and, on the whole, the most eminent of
those who have aspired to tread in the footsteps
of Grotius.
The fundamental principles of Puffendorff
possess little merit in point of originality, being
a sort of medley of the doctrines of Grotius,
with some opinions of Hobbes; but his hook is
entitled to the praise of comparative conciseness,
order, and perspicuity; and accordingly came
very generally to supplant the treatise of Gro¬
tius, as a manual or institute for students, not¬
withstanding its immense inferiority in genius,
in learning, and in classical composition.
The authors who, in different parts of the
Continent, have since employed themselves in
commenting on Grotius and Puffendorff; or in
abridging their systems; or in altering their ar¬
rangements, are innumerable: but notwithstand¬
ing all their industry and learning, it would be
very difficult to name any class of writers whose
labours have been of less utility to the world.
The same ideas are constantly recurring in an
eternal circle; the opinions of Grotius and of
Puffendorff, where they are at all equivocal, are
anxiously investigated, and sometimes involved
in additional obscurity; while, in the meantime,
the science of Natural Jurisprudence never ad¬
vances one single step; hut, notwithstanding its
recent birth, seems already sunk into a state of
dotage.2
In perusing the systems now referred to, it is
impossible not to feel a very painful dissatisfac¬
tion, from the difficulty of ascertaining the pre¬
cise object aimed at by the authors. So vague
1 From a letter of Grotius, quoted by Gassendi, we learn, that the treatise De Jure Belli et Pads was undertaken at the
request of his learned friend Peireskius. “ Non otior, sed in illo de jure gentium opere pergo, quod si tale futurum est,^ut
lectores demereri possit, habebit quod tibi debeat posteritas, qui me ad hunc laborem et auxilio et hortatu tuo excitasti.
Gassendi Opera, Tom. Y. p. 294. . ,
2 I have borrowed, in this last paragraph, some expressions from Lampredi. “ Grotii et Puffendorfii interpretes, yin
quidem diligentissimi, sed qui vix fructum aliquem tot commentariis, adnotationibus, compendiis, tabulis, caeterisque ejus-
modi aridissimis laboribus attulerunt: perpetuo circulo eadem res circumagitur, quid uterque senserit quaeritur, internum
etiam utriusque sententiae obscurantur; disciplina nostra tamen ne latum quidem unguem progreditur, et dum aliorum
sententiae disquiruntur et explanantur, Rerum Natura quasi senio confecta squalescit, neglectaque jacet et inobservata
omnino.—(Juris Publici Thcoremata, p. 34.)
86
PRELIMINARY DISSERTATIONS.
and indeterminate is the general scope ot their
researches, that not only are different views of
the subject taken hy different writers, hut even
by the same writer in different parts of his
work;—a circumstance which, of itself, suffi¬
ciently accounts for the slender additions they
have made to the stock of useful knowledge;
and which is the real source of that chaos of
heterogeneous discussions, through which the
reader is perpetually forced to fight his way. A
distinct conception of these different views will
be found to throw more light than might at first
be expected on the subsequent history of Moral
and of Political Science; and I shall therefore
endeavour, as accurately as I can, to disen¬
tangle and separate them from each other, at
the risk perhaps of incurring, from some read¬
ers, the charge of prolixity. The most import¬
ant of them may, I apprehend, be referred to
one or other of the following heads :
1. Among the different ideas which have
been formed of Natural Jurisprudence, one of
the most common (particularly in the earlier
systems) supposes its object to he—to lay down
those rules of justice which would he binding on
men living in a social state, without any posi¬
tive institutions; or (as it is frequently called
by writers on this subject), living together in a
state of nature. This idea of the province of
Jurisprudence seems to have been uppermost in
the mind of Grotius, in various parts of his
treatise.
To this speculation about the state of nature,
Grotius was manifestly led by his laudable anxi¬
ety to counteract the attempts then recently
made to undermine the foundations of morality.
That moral distinctions are created entirely by
the arbitrary and revealed will of God, had, be¬
fore his time, been zealously maintained by some
theologians even of the reformed church; while,
among the political theorists of the same period,
it was not unusual to refer these distinctions (as
was afterwards done hy Hobbes) to the positive
institutions of the civil magistrate. In opposi¬
tion to both, it was contended hy Grotius, that
there is a natural law coeval with the human
constitution, from which positive institutions
derive all their force; a truth which, how ob¬
vious and trite soever it may now appear, was
so opposite in its spirit to the illiberal systems
taught in the monkish establishments, that he
thought it necessary to exhaust in its support
all his stores of ancient learning. The older
waiters on Jurisprudence must, I think, he al¬
lowed to have had great merit in dwelling so
much on this fundamental principle; a principle
which renders “ Man a Law to himself;” and
which, if it be once admitted, reduces the meta¬
physical question concerning the nature of the
moral faculty, to an object merely of speculative
curiosity.1 2 To this faculty the ancients fre¬
quently give the name of reason; as in that
noted passage of Cicero, where he observes, that
“ right reason is itself a law ; congenial to the
feelings of nature; diffused among all men;
uniform ; eternal; calling us imperiously to our
duty, and peremptorily prohibiting every viola¬
tion of it. Nor does it speak,” continues the
same author, “ one language at Rome and ano¬
ther at Athens, varying from place to place, or
time to time; hut it addresses itself to all na¬
tions and to all ages; deriving its authority
from the common sovereign of the universe, and
carrying home its sanctions to every breast, hy
the inevitable punishment which it inflicts on
transgressors.”3
The habit of considering morality under the
similitude of a law (a law engraved on the hu¬
man heart), led not unnaturally to an applica¬
tion to ethical subjects of the technical language
and arrangements of the Roman jurisprudence,
and this innovation was at once facilitated and
1 “ Upon whatever we suppose that our moral faculties are founded, whether upon a certain modification of reason, upon
an original instinct, called a moral sense, or upon some other principle of our nature, it cannot be doubted that they were
given us for the direction of our conduct in this life. They carry along with them the most evident badges of this autho¬
rity, which denote that they were set up within us to be the supreme arbiters of all our actions, to superintend all our
senses, passions, and appetites, and to judge how far each of them was either to be indulged or restrained. The rules,
therefore, which they prescribe, are to be regarded as the commands and laws of the Deity, promulgated by those vicege¬
rents which he has set up within us.”—Smith’s Theory of Moral Sentiments, Part in. chap, v.)—See also Dr Butler’s very
original and philosophical Discourses on Human Nature.
2 Frag. Lib. iii. de Hep.
DISSERTATION FIRST.
87
encouraged, by certain peculiarities in the nature
of the most important of all the virtues,—that
of justice; peculiarities which, although first
explained fully by Hume and Smith, were too
prominent to escape altogether the notice of pre¬
ceding moralists.
The circumstances which distinguish justice
from the other virtues, are chiefly two. In the
first place, its rules may be laid down with a
degree of accuracy, whereof moral precepts do
not, in any other instance, admit. Secondly,
its rules may he enforced, inasmuch as every
transgression of them implies a violation of the
rights of others. For the illustration of both
propositions, I must refer to the eminent au¬
thors just mentioned.
As, in the case of justice, there is always a
right, on the one hand, corresponding to an obliga¬
tion on the other, the various rules enjoined hy
it may be stated in two different forms; either
as a system of duties, or as a system of rights.
The former view of the subject belongs properly
to the moralist—the latter to the lawyer. It is
this last view that the writers on Natural Juris¬
prudence (most of whom were lawyers hy pro¬
fession) have in general chosen to adopt; al¬
though, in the same works, both views will he
found to be not unfrequently blended together.
To some indistinct conception among the earlier
writers on Natural Law, of these peculiarities
in the nature of justice, we may probably ascribe
the remarkable contrast pointed out by Mr
Smith, between the ethical systems of ancient
and of modern times. “ In none of the ancient
moralists,” he observes, “ do we find any at¬
tempt towards a particular enumeration of the
rules of justice. On the contrary, Cicero in his
Offices, and Aristotle in his Ethics, treat of jus¬
tice in the same general manner in which they
treat of generosity or of charity.”1
But although the rules of justice are in every
case precise and indispensable; and although
their authority is altogether independent of that
of the civil magistrate, it would obviously be
absurd to spend much time in speculating about
the principles of this natural law, as applicable
to men, before the establishment of government.
The same state of society which diversifies the
condition of individuals to so great a degree as
to suggest problematical questions with respect
to their rights and their duties, necessarily gives
birth to certain conventional laws or customs,
by which the conduct of the different members
of the association is to be guided; and agreeably
to which the disputes that may arise among them
are to be adj usted. The imaginary state refer¬
red to under the title of the State of Nature,
though it certainly does not exclude the idea of
a moral right of property arising from labour, yet
excludes all that variety of cases concerning its
alienation and transmission, and the mutual co¬
venants of parties, which the political union
alone could create;—an order of things, indeed,
winch is virtually supposed in almost all the spe¬
culations about which the law of nature is com¬
monly employed.
2. It was probably in consequence of the very
narrow field of study which Jurisprudence, con¬
sidered in this light, was found to open, that its
province was gradually enlarged, so as to com¬
prehend, not merely the rules of justice, but the
rules enjoining all our other moral duties. Nor
was it only the province of Jurisprudence which
was thus enlarged. A corresponding extension
was also given, by the help of arbitrary defini¬
tions, to its technical phraseology, till at length
the whole doctrines of practical ethics came to
he moulded into an artificial form, originally
copied from the Roman code. Although justice
is the only branch of virtue in which every mo¬
ral Obligation implies a corresponding Right,
the writers on Natural Law have contrived, hy
fictions of imperfect rights, and of external rights,
to treat indirectly of all our various duties, by
pointing out the rights which are supposed to be
their correlates:—in other words, they have con¬
trived to exhibit, in the form of a system of
rights, a connected view of the whole duty of
man. This idea of Jurisprudence, which iden¬
tifies its object with that of Moral Philosophy,
seems to coincide nearly with that of Puffen-
dorff; and some vague notion of the same sort
1 Theory of Moral Sentimentt, Part vii. sect. iy.
PRELIMINARY DISSERTATIONS.
has manifestly given birth to many of the di¬
gressions of Grotius.
Whatever judgment may now be pronounced
on the effects of this innovation, it is certain
that they were considered, not only at the time,
but for many years afterwards, as highly fa’s our-
able. A very learned and respectable writer,
Mr Carmichael of Glasgow, compares them to
the improvements made in Natural Philosophy
by the followers of Lord Bacon. No person,
he observes, “ liberally educated, can be igno¬
rant, that, within the recollection of ourselves
and of our fathers, philosophy has advanced to
a state of progressive improvement hitherto un¬
exampled ; in consequence partly of the rejection
of scholastic absurdities, and partly of the ac¬
cession of new discoveries. Nor does this re¬
mark apply solely to Natural Philosophy, in
which the improvements accomplished by the
united labours of the learned have forced them¬
selves on the notice even of the vulgar, by their
palpable influence on the mechanical arts. The
other branches of philosophy also have been pro¬
secuted during the last century with no less suc¬
cess ; and none of them in a more remarkable
degree than the science of Morals.
u This science, so much esteemed, and so as¬
siduously cultivated by the sages of antiquity,
lay, for a length of time, in common with all the
other useful arts, buried in the rubbish of the
dark ages, till (soon after the commencement of
the seventeenth century), the incomparable
treatise of Grotius de Jure Belli et Pads restored
to more than its ancient splendour that part of
it which defines the relative duties of individu¬
als ; and which, in consequence of the immense
variety of cases comprehended under it, is by
far the most extensive of any. Since that period,
the most learned and polite scholars of Europe,
as if suddenly roused by the alarm of a trumpet,
have vied with each other in the prosecution of
this study,—so strongly recommended to their
attention, not merely by its novelty, but by the
importance of its conclusions, and the dignity
of its object.”1
I have selected this passage, in preference to
many others that might be quoted to the same
purpose from writers of higher name; because,
in the sequel of this historical sketch, it appears
to me peculiarly interesting to mark the progress
of Ethical and Political speculation in that seat
of learning, which, not many years afterwards,
was to give birth to the Theory of Moral Senti¬
ments, and to the Inquiry into the Nature and Causes
of the Wealth of Nations. The powerful effect
which the last of these works has produced on
the political opinions of the whole civilised world,
renders it unnecessary, in a Discourse destined
to form part of a Scotish Encyclopedia, to offer
any apology for attempting to trace, with some
1 The last sentence is thus expressed in the original. “ Ex illo tempore, quasi classico dato, ah eruditissirms Passim et
politissimis viris excoli certatim coepit, utilissima hsec nohilissimaque doctrina.”—See the edition ot i utiendortt, De (JJicio
Hominis et Civis, by Professor Gerschom Carmichael of Glasgow, 1724; an author whom Dr Hutchison pronounces to^be
“ by far the best commentator on PuffendorfF; and “ whose notes," he adds, “ are of much more value than the text.
See his short Introduction to Moral Philosophy. _ • ., .
PuffendorfPs principal work, entitled De Jure Naturae et Gentium, was first printed in 1672, and was aiterwards abridge
by the author into the small volume referred to in the foregoing paragraph. The idea of Fuffendorff s "y™? rormed by rlr
Carmichael, coincides exactly with the account of it given in the text: “ Hoc demum tractatu edito, iacile intellexerunt
sequiores harum rerum arbitri, non aliam esse genuinam Morum Philosophiam, quam quae ex evidentibus prmcipus, m ipsa
rerum natura fundatis, hominis atque civis officia, in singulis vitae humanae circumstantiis debita, eruit ac demonstrat,
atque adeo Juris Naturalis scientiam, quantumvis diversam ab Ethica quae in scholis dudum obtinuerat, prae se lerret
faciem, non esse, quod ad scopum et rem tractandam, vere aliam disciplinam, sed eandem rectius duntaxat et sohdius tra-
ditam, ita ut, ad quam prius male collineaverit, tandem reipsa feriret scopum.”—See Carmichael s edition ot the treatise
De Officio Hominis et Civis, p. 7- _ . .
To so late a period did this admiration of the treatise De Officio Hominis et Civis, continue in our Scotch Universities,
that the very learned and respectable Sir John Pringle (afterwards President of the lloyal Society of London), adopted it
as the text-bcok for his lectures, while he held the Professorship of Moral Philosophy at Edinburgh. Nor does the case
seem to have been different in England. “ I am going,” says Gray, in a letter written while a student at Cambridge, “ to
attend a lecture on one Puffendorff” And, much in the same spirit, Voltaire thus expresses himself with respect to the
schools of the Continent:—“ On est partage, dans les dcoles, entre Grotius et Puffendorff. Croyez-moi, hsez les Offices
de Ciceron.” From the contemptuous tone of these two writers, it should seem that the old systems of Natural Jurispru¬
dence had entirely lost their credit among men of taste and of enlarged views, long before they ceased to form an essential
part of academical instruction; thus affording an additional confirmation of Mr Smith’s complaint, that the greater part ot
universities have not been very forward to adopt improvements after they were made; and that several of those learned
societies have chosen to remain, for a long time, the sanctuaries in which exploded systems found shelter and protection,
after they had been hunted out of every other corner of the world.” Considering his own successful exertions in his aca¬
demical capacity, to remedy this evil, it is more than probable that Mr Smith had Grotius and Puffendorff in his view
when he wrote the foregoing sentence.
DISSERTATION FIRST.
89
minuteness, the train of thought by which an
undertaking, so highly honourable to the lite¬
rary character of our country, seems to have
been suggested to the author.
The extravagance of the praise lavished on
Grotius and Puffendorff, in the above citation
from Carmichael, can he accounted for only by
the degraded state into which Ethics had fallen
in the hands of those who were led to the study
of it, either as a preparation for the casuistical
discussions subservient to the practice ofauricular
confession, or to justify a scheme of morality
which recommended the useless austerities of an
ascetic retirement, in preference to the manly
duties of social life. The practical doctrines
inculcated by the writers on Natural Law, were
all of them favourable to active virtue; and, how
reprehensible soever in point of form, were not
only harmless, but highly beneficial in their
tendency. They were at the same time so di¬
versified (particularly in the work of Grotius)
with beautiful quotations from the Greek and
Roman classics, that they could not fail to pre¬
sent a striking contrast to the absurd and illibe¬
ral systems which they supplanted; and per¬
haps to these passages, to which they thus gave
a sort of systematical connection, the progress
which the science made in the course of the
eighteenth century may, in no inconsiderable
degree, be ascribed. Even now, when so very
different a taste prevails, the treatise de Jure
Belli et Pads possesses many charms to a classi¬
cal reader; who, although he may not always
set a very high value on the author’s reasonings,
must at least be dazzled and delighted with the
splendid profusion of his learning.
The field of Natural Jurisprudence, however,
was not long to remain circumscribed within the
narrow limits commonly assigned to the province
of Ethics. The contrast between natural law
and positive institution, which it constantly pre¬
sents to the mind, gradually and insensibly
suggested the idea of comprehending under it
every question concerning right and wrong, on
which positive law is silent. Hence the origin
of two different departments of Jurisprudence,
little attended to by some of the first authors
who treated of it, but afterwards, from their
practical importance, gradually encroaching
DISS. I. PART. I.
more and more on those ethical disquisitions by
which they were suggested. Of these depart¬
ments, the one refers to the conduct of indivi¬
duals in those violent and critical moments when
the bonds of political society are torn asunder;
the other, to the mutual relations of independ¬
ent communities. The questions connected with
the former article, lie indeed within a compara¬
tively narrow compass; but on the latter so
much has been written, that what was formerly
called Natural Jurisprudence, has been, in later
times, not unfrequently distinguished by the
title of the Law of Nature and Nations. The
train of thought by which both subjects came to
be connected with the systems now under con¬
sideration, consists of a few very simple and
obvious steps.
As an individual who is a member of a politi¬
cal body necessarily gives up his will to that of
the governors who are entrusted by the people
with the supreme power, it is his duty to sub¬
mit to those inconveniences which, in conse¬
quence of the imperfection of all human esta¬
blishments, may incidentally fall to his own lot.
This duty is founded on the Law of Nature,
from which, indeed, (as must appear evident on
the slightest reflection) conventional law derives
all its moral force and obligation. The great
end, however, of the political union being a
sense of general utility, if this end should be
manifestly frustrated, either by the injustice of
laws, or the tyranny of rulers, individuals must
have recourse to the principles of Natural Law,
in order to determine how far it is competent
for them to withdraw themselves from their
country, or to resist its governors by force. To
Jurisprudence, therefore, considered in this light,
came with great propriety to be referred all
those practical discussions which relate to the
limits of allegiance, and the right of resistance.
By a step equally simple, the province of the
science was still farther extended. As inde¬
pendent states acknowledge no superior, the
obvious inference was, that the disputes arising
among them must be determined by an appeal
to the Law of Nature ; and accordingly, this law,
when applied to states, forms a separate part of
Jurisprudence, under the title of the Law of Na¬
tions. By some writers we are told, that the
M
90
PRELIMINARY DISSERTATIONS.
general principles of the Law of Nature, and of
the Law of Nations, are one and the same, and
that the distinction between them is merely ver¬
bal. To this opinion, which is very confidently
stated by Hobbes,1 PuffendorfF has given his
sanction ; and in conformity to it, contents him¬
self with laying down the general principles of
Natural Law, leaving it to the reader to apply it
as he may find necessary, to individuals or to
societies.
The later writers on Jurisprudence have
thought it expedient to separate the law of na¬
tions from that part of the science which treats
of the duties of individuals;8 but without being
at sufficient pains to form to themselves a definite
idea of the object of their studies. Whoever
takes the trouble to look into their systems, will
immediately perceive, that their leading aim is
not, as might have been expected, to ascertain
the great principles of morality binding on all
nations in their intercourse with each other; or
to point out with what limitations the ethical
rules recognised among individuals must be
understood, when extended to political and un¬
connected bodies; but to exhibit a digest of
those laws and usages, which, partly from con¬
siderations of utility, partly from accidental cir¬
cumstances, and partly from positive conven¬
tions, have gradually arisen among those states
of Christendom, which, from their mutual con¬
nections, may be considered as forming one great
republic. It is evident, that such a digest has
no more connection with the Law of Nature,
properly so called, than it has with the rules of
the Roman Law, or of any other municipal code.
The details contained in it are highly interesting
and useful in themselves ; but they belong to a
science altogether different; a science, in which
the ultimate appeal is made, not to abstract
maxims of right and wrong, but to precedents,
to established customs, and to the authority of
the learned.
The intimate alliance, however, thus establish¬
ed between the Law of Nature and the conven¬
tional Law of Nations, has been on the whole
attended with fortunate effects. In consequence
of the discussions concerning questions of justice
and of expediency which came to be blended
with the details of public law, more enlarged
and philosophical views have gradually present¬
ed themselves to the minds of speculative states¬
men ; and, in the last result, have led, by easy
steps, to those liberal doctrines concerning com¬
mercial policy, and the other mutual relations
of separate and independent states, which, if they
should ever become the creed of the rulers of
mankind, promise so large an accession to hu¬
man happiness.
* “ Lex Naturalis dividi potest in naturalem hominum quae sola obtinuit did Lex Naturae, et naturalem dvitatum
quae did potest Lex Gentium, vulgo autem Jus Gentium appellatur. Praecepta utriusque eadem sunt; sed quia dvitates
semel institutae induunt proprietates hominum personales, lex quam loquentes de hominum singulorum officio naturalem
dicimus, applicata totis civitatibus, nationibus, sive gentibus, vocatur Jus Gentium.”—De Give, cap. xiv. § 4.
In a late publication, from the title of which some attention to dates might have been expected, we are told, that
“ Hobbes’s book De Give appeared but a little time before the treatise of Grotius whereas, in point of fact, Hobbes’s book
did not appear till twenty-two years after it. A few copies were indeed printed at Paris, and privately circulated by Hobbes,
as early as 1642, but the book was not published till 1647-—(See “ An Inquiry into the Foundation and History of the Law of
Nations in Europe” &c. by Robert Ward of the Inner Temple, Esq. London, 1795). This inaccuracy, however, is trifling,
when compared with those committed in the same work, in stating the distinguishing doctrines of the two systems.
As a writer on the Law of Nations, Hobbes is now altogether unworthy of notice. I shall therefore only remark on this
part of his philosophy, that its aim is precisely the reverse of that of Grotius; the latter labouring, through the whole of
his treatise, to extend, as far as possible, among independent states, the same laws of justice and of humanity which are
universally recognised among individuals ; while Hobbes, by inverting the argument, exerts his ingenuity to shew, that
the moral repulsion which commonly exists between independent and neighbouring communities, is an exact picture of that
which existed among individuals prior to the origin of government. The inference, indeed, was most illogical, inasmuch
as it is the social attraction among individuals which is the source of the mutual repulsion among nations, and as this at¬
traction invariably operates with the greatest force where the individual is the most completely independent of his
species, and where the advantages of the political union are the least sensibly felt. If, in any state of human nature, it be
in danger of becoming quite evanescent, it is in large and civilised empires, where man becomes indispensably necessary to
man, depending for the gratification of his artificial wants on the co-operation of thousands of his fellow citizens.
Let me add, that the theory so fashionable at present, which resolves the whole of morality into the principle of utility*
is more nearly akin to Hobbism, than some of its partisans arc aware of.
I he credit of Uiis improvement is ascribed by Vattel (one of the most esteemed writers on the subject), to the cele¬
brated German philosopher \Y oliius, whose labours in this department of study he estimates very highly (Questions de
Droit Nature! Berne, 1762.) Of this great work I know nothing but the title, which is not calculated to excite much
curiosity in the present times : “ Christiani Wolfii Jus Naturae methodo scientijica pertractatum, in 9 Tomos distributum.”
(brancof. 1740.) “Nonest,” says Lampredi, himself a professor of public law, “ qui non deterreatur tanta librorum
farragine, quasi vero Herculeo labore opus esset ut quis honestatem et justitiam addiscat.”
DISSERTATION FIRST.
91
3. Another idea of Natural Jurisprudence,
essentially distinct from those hitherto mention¬
ed, remains to he considered. According to
this, its object is to ascertain the general prin¬
ciples of justice which ought to he recognised in
every municipal code; and to which it ought to
be the aim of e^ery legislator to accommodate
his institutions. It is to this idea of Jurispru¬
dence that Mr Smith has given his sanction in
the conclusion of his Theory of Moral Senti¬
ments ; and this he seems to have conceived to
have been likewise the idea of Grotius, in the
treatise de Jure Belli et Pacts.
£t It might have been expected,” says Mr
Smith, {C that the reasonings of lawyers upon
the different imperfections and improvements
of the laws of different countries, should have
given occasion to an inquiry into what were
the natural rules of justice, independent of all
positive institution. It might have been ex¬
pected, that these reasonings should have led
them to aim at establishing a system of what
might properly be called Natural Jurisprudence,
or a theory of the principles which ought to run
through^ and to he the foundation of the laws of all
nations. But, though the reasonings of lawyers
did produce something of this kind, and though
no man has treated systematically of the laws of
any particular country, without intermixing in
his work many observations of this sort, it was
very late in the world before any such general
system was thought of, or before the philosophy
of laws was treated of by itself, and without
regard to the particular institutions of any na¬
tion. Grotius seems to have been the first who
attempted to give the world any thing like a
system of those principles which ought to run
through, and be the foundation of the laws of
all nations; and his Treatise of the Laws of
Peace and War, with all its imperfections, is per¬
haps, at this day, the most complete work that
has yet been given on the subject.”
Whether this was, or was not, the leading
object of Grotius, it is not material to decide;
but if this was his object, it will not be disputed
that he has executed his design in a very desul¬
tory manner, and that he often seems to have
lost sight of it altogether, in the midst of those
miscellaneous speculations on political, ethical,
and historical subjects, which form so large a
portion of his Treatise, and which so frequently
succeed each other without any apparent con¬
nection or common aim.1
Nor do the views of Grotius appear always
enlarged or just, even when he is pointing at
the object described by Mr Smith. The Roman
system of Jurisprudence seems to have warped,
in no inconsiderable degree, his notions on all
questions connected with the theory of legisla¬
tion, and to have diverted his attention from
that philosophical idea of law, so well expressed
by Cicero,—“ Non a prsetoris edicto, neque a
duodecim tabulis, sed penitus ex intima philo-
sophia, hauriendam juris disciplinam.” In this
idolatry, indeed, of the Roman law, he has not
gone so far as some of his commentators, who
have affirmed, that it is only a different name
for the Law of Nature; but that his partiality
for his professional pursuits has often led him to
overlook the immense difference between the
state of society in ancient and modern Europe,
will not, I believe, be now disputed. It must,
at the same time, be mentioned to his praise,
that no writer appears to have been, in theory)
more completely aware of the essential distinc¬
tion between Natural and Municipal laws. In
one of the paragraphs of his Prolegomena) he
mentions it as a part of his general plan, to illus¬
trate the Roman code, and to systematise those
parts of it which have their origin in the Law
of Nature. <£ The task,” says he, ££ of mould¬
ing it into the form of a system, has been pro¬
jected by many, but hitherto accomplished by
none. Nor indeed was the thing possible, while
so little attention was paid to the distinction
between natural and positive institutions; for
the former being everywhere the same, may be
easily traced to a few general principles, while
the latter, exhibiting different appearances at
different times, and in different places, elude
1 “ Of what stamp,” says a most ingenious and original thinker, “ are the works of Grotius, Puffendorff, and Ilurla-
maqui? Are they political or ethical, historical or juridical, expository or censorial?—Sometimes one thing, sometimes
another: they seem hardly to have settled the matter with themselves.”—Bentham’s Introduction to the Principles of Mo.
rals and Legislation, p. 327.
92
PRELIMINARY DISSERTATIONS.
every attempt towards methodical arrangement,
no less than the insulated facts which indi¬
vidual objects present to our external senses.”
This passage of Grotius has given great of¬
fence to two of the most eminent of his com¬
mentators, Henry and Samuel de Cocceii, who
have laboured much to vindicate the Roman le¬
gislators against that indirect censure which the
words of Grotius appear to convey. “ My chief
object,” says the latter of those writers, “ was,
by deducing the Roman Law from its source in
the nature of things, to reconcile Natural Juris¬
prudence with the civil code; and, at the same
time, to correct the supposition implied in the
foregoing passage of Grotius, which is indeed one
of the most exceptionable to he found in his work.
The remarks on this subject, scattered over the
following commentary, the reader will find ar¬
ranged in due order in my twelfth Preliminary
Dissertation, the chief design of which is to sys¬
tematise the whole Roman Law, and to demon¬
strate its beautiful coincidence with the Law of
Nature.” In the execution of this design, Coc¬
ceii must, I think, he allowed to have contri¬
buted a very useful supplement to the jurispru¬
dential labours of Grotius, the Dissertation in
question being eminently distinguished by that
distinct and luminous method, the want of
which renders the study of the treatise de Jure
Belli et Pads so peculiarly irksome and unsatis¬
factory.
The superstitious veneration for the Roman
code expressed by such writers as the Cocceii,
will appear less wonderful, when we attend to
the influence of the same prejudice on the libe¬
ral and philosophical mind of Leibnitz; an au¬
thor who has not only gone so far as to com¬
pare the civil law (considered as a monument
of human genius) with the remains of the an¬
cient Greek geometry; but has strongly inti¬
mated his dissent from the opinions of those who
have Represented its principles as being fre¬
quently at variance with the Law of Nature.
In one very powerful paragraph, he expresses
himself thus t—“ I have often said, that, after
the writings of geometricians, there exists no¬
thing which, in point of strength, subtlety, and
depth, can be compared to the works of the Ro¬
man lawyers. And as it would be scarcely pos¬
sible, from mere intrinsic evidence, to distin¬
guish a demonstration of Euclid’s from one of
Archimedes or of Appollonius (the style of all
of them appearing no less uniform than if rea¬
son herself were speaking through their organs),
so also the Roman lawyers all resemble each
other like twin-brothers; inasmuch that, from
the style alone of any particular opinion or ar¬
gument, hardly any conjecture could be formed
about its author. Nor are the traces of a re¬
fined and deeply meditated system of Natural Ju¬
risprudence anywhere to be found more visible,
or in greater abundance. And even in those
cases where its principles are departed from,
either in compliance with the language conse¬
crated by technical forms, or in consequence of
new statutes, or of ancient traditions, the con¬
clusions which the assumed hypothesis renders
it necessary to incorporate with the eternal dic¬
tates of right reason, are deduced with the
soundest logic, and with an ingenuity that ex¬
cites admiration. Nor are these deviations from
the Law of Nature so frequent as is commonly
apprehended.”
In the last sentence of this passage, Leibnitz
had probably an eye to the works of Grotius and
his followers; which, however narrow and ti¬
mid in their views they may now appear, were,
for a long time, regarded among civilians as
savouring somewhat of theoretical innovation,
and of political heresy.
To all this may be added, as a defect still
more important and radical in the systems of
Natural Jurisprudence considered as models of
universal legislation, that their authors reason
concerning laws too abstractedly, without spe¬
cifying the particular circumstances of the so¬
ciety to which they mean that their conclusions
should be applied. It is very justly observed
by Mr Bentham, that “ if there are any books
of universal Jurisprudence, they must be look¬
ed for within very narrow limits.” He cer¬
tainly, however, carries this idea too far, when
he asserts, that 44 to be susceptible of an uni¬
versal application, all that a book of the expo¬
sitory kind can have to treat of is the import
of words; and that, to be strictly speaking
universal, it must confine itself to terminology;
that is, to an explanation of such words con-
DISSERTATION FIRST.
93
nected with law, as power, right, obligation, li¬
berty, to which are words pretty exactly cor¬
respondent in all languages.”1 His expres¬
sions, too, are somewhat unguarded, when he
calls the Law of Nature “ an obscure phantom,
which in the imaginations of those who go in
chase of it, points sometimes to manners, some¬
times to laws, sometimes to what law is, some¬
times to what it ought to be.”q Nothing, indeed,
can he more exact and judicious than this de¬
scription, when restricted to the Law of Nature,
as commonly treated of hy writers on Jurispru¬
dence ; hut if extended to the Law of Nature, as
originally understood among ethical writers, it
is impossible to assent to it, without abandon¬
ing all the principles on which the science of
morals ultimately rests. With these obvious,
hut, in my opinion, very essential limitations, I
perfectly agree with Mr Bentham, in consider¬
ing an abstract code of laws as a thing equally
unphilosophical in the design, and useless in the
execution.
In stating these observations, I would not be
understood to dispute the utility of turning the
attention of students to a comparative view of
the municipal institutions of different nations;
hut only to express my doubts whether this can
be done with advantage, hy referring these in¬
stitutions to that abstract theory called the Law
of Nature, as to a common standard. The code
of some particular country must he fixed on as
a groundwork for our speculations; and its laws
studied, not as consequences of any abstract
principles of justice, hut in their connection
with the circumstances of the people among
whom they originated. A comparison of these
laws with the corresponding laws of other na¬
tions, considered also in their connection with
the circumstances whence they arose, would
form a branch of study equally interesting and
useful, not merely to those who have in view
the profession of law, hut to all who receive the
advantages of a liberal education. In fixing on
such a standard, the preference must undoubt¬
edly he given to the Roman Law, if for no other
reason than this, that its technical language is
more or less incorporated with all our munici¬
pal regulations in this part of the world: and
the study of this language, as well as of the
other technical parts of Jurisprudence (so re¬
volting to the taste when considered as the ar¬
bitrary jargon of a philosophical theory), would
possess sufficient attractions to excite the curio¬
sity, when considered as a necessary passport to
a knowledge of that system which so long de¬
termined the rights of the greatest and most
celebrated of nations.
<£ Universal grammar,” says Hr Lowth,
“ cannot he taught abstractedly; it must be
done with reference to some language already
known, in which the terms are to he explained
and the rules exemplified.”3 The same obser¬
vation may he applied (and for reasons strik¬
ingly analogous) to the science of Natural or
Universal Jurisprudence.
Of the truth of this last proposition Bacon
seems to have been fully aware; and it was
manifestly some ideas of the same kind which
gave birth to Montesquieu’s historical specula¬
tions with respect to the origin of laws, and the
reference which they may he expected to hear,
in different parts of the world, to the physical
and moral circumstances of the nations among
whom they have sprung up. During this long
interval, it would he difficult to name any in¬
termediate writer, by whom the important con¬
siderations just stated were duly attended to.
In touching formerly on some of Bacon’s
ideas concerning the philosophy of law, I quoted
a few of the most prominent of those fortunate
anticipations, so profusely scattered over his
works, which, outstripping the ordinary march
of human reason, associate his mind with the
luminaries of the eighteenth century, rather
than with his own contemporaries. These an¬
ticipations, as well as many others of a similar
description, hazarded by his hold yet prophetic
imagination, have often struck me as resembling
the pierres d’attente j utting out from the corners
of an ancient building, and inviting the fancy
to complete what was left unfinished of the
architect’s design;—or the slight and broken
sketches traced on the skirts of an American
1 Introduction to the Principles of Morals and Legislation, p. 323.
Ibid. p. 327. 3 Preface to his English Grammar.
94
PRELIMINARY DISSERTATIONS.
map, to connect its chains of hills and branches
of rivers with some future survey of the con¬
tiguous wilderness. Yielding to such impres¬
sions, and eager to pursue the rapid flight of
his genius, let me abandon for a moment the
order of time, while I pass from the Fontes Ju¬
ris to the Spirit of Laws. To have a just con¬
ception of the comparatively limited views of
Grotius, it is necessary to attend to what was
planned by his immediate predecessor, and first
executed (or rather first begun to he executed)
by one of his remote successors.
The main object of the Spirit of Laws (it is
necessary here to premise) is to show, not, as
has been frequently supposed, what laws ought
to be, but how the diversities in the physical
and moral circumstances of the human race
have contributed to produce diversities in their
political establishments, and in their municipal
regulations.1 On this point, indeed, an appeal
may he made to the author himself. “ I write
not,” says he, “ to censure any thing establish¬
ed in any country whatsoever; every nation
will here find the reasons on which its maxims
are founded.” This plan, however, which,
when understood with proper limitations, is
highly philosophical, and which raises Juris¬
prudence, from the uninteresting and useless
state in which we find it in Grotius and Puffen-
dorff, to be one of the most agreeable and im¬
portant branches of useful knowledge (although
the execution of it occupies by far the greater
part of his work), is prosecuted by Montesquieu
in so very desultory a manner, that I am in¬
clined to think he rather fell into it insensibly,
in consequence of the occasional impulse of ac¬
cidental curiosity, than from any regular de¬
sign he had formed to himself when he began
to collect materials for that celebrated perform¬
ance. He seems, indeed, to confess this in the
following passage of his preface : “ Often have
I begun, and as often laid aside, this undertak¬
ing. I have followed my observations without
any fixed plan, and without thinking either of
rules or exceptions. I have found the truth
only to lose it again.”
But whatever opinion we may form on this
point, Montesquieu enjoys an unquestionable
claim to the grand idea of connecting Juris¬
prudence with History and Philosophy, in such
a manner as to render them all subservient to
their mutual illustration. Some occasional dis¬
quisitions of the same kind may, it is true, he
traced in earlier writers, particularly in the
works of Bodinus; hut they are of a nature too
trifling to detract from the glory of Montesquieu.
When we compare the jurisprudential researches
of the latter with the systems previously in pos¬
session of the schools, the step which he made
appears to have been so vast as almost to justify
the somewhat too ostentatious motto prefixed to
them by the author; Prolem sine Matre creatam.
Instead of confining himself, after the example of
his predecessors, to an interpretation of one part
of the Roman code by another, he studied the
Spirit of these laws in the political views of
their authors, and in the peculiar circumstances
of that extraordinary race. He combined the
science of law with the history of political
society, employing the latter to account for the
varying aims of the legislator; and the former,
in its turn, to explain the nature of the govern¬
ment, and the manners of the people. Nor did
he limit his inquiries to the Roman Law, and to
Roman History; but, convinced that the general
principles of human nature are everywhere the
same, he searched for new lights among the sub¬
jects of every government, and the inhabitants
of every climate; and, while he thus opened
inexhaustible and unthought of resources to the
student of Jurisprudence, he indirectly marked
out to the legislator the extent and the limits of
his power, and recalled the attention of the
philosopher from abstract and useless theories,
to the only authentic monuments of the history
of mankind.2
is, t ough somewhat ambiguously expressed, must, I think, have been the idea of D’Alembert in the following sen-
,eJJ,ce * ®uvraSe’ de Montesquieu s’occupe moins des loix qu’on a faites, que de celles qu’on a du faire.” 
, ?gc e •. e ontesqmeu.) According to the most obvious interpretation of his words, they convey a meaning
which I conceive to be the very reverse of the truth.
, . * exa-™ples ot Montesquieu s peculiar and characteristical style of thinking in The Spirit of Laws, may be mentioned
is serva ions on tie Origin and Revolutions of the Roman Laws on Successions ; and what he has written on the History of the
ivi aws in his own Country ; above all, his Theory of the Feudal Laws among the Franks, considered in relation to the re-
DISSERTATION FIRST.
95
This view of law, which unites History and
Philosophy with Jurisprudence, has been follow¬
ed out with remarkable success by various au¬
thors since Montesquieu’s time; and for a con¬
siderable number of years after the publication
of the Spirit of Laws, became so very fashionable,
particularly in this country, that many seem
to have considered it, not as a step towards a
farther end, but as exhausting the whole science
of Jurisprudence. For such a conclusion there
is undoubtedly some foundation, so long as we
confine our attention to the ruder periods of so¬
ciety, in which governments and laws may be
universally regarded as the gradual result of
time and experience, of circumstances and emer¬
gencies. In enlightened ages, however, there
cannot be a doubt, that political wisdom comes
in for its share in the administration of human
affairs; and there is reasonable ground for hop¬
ing, that its influence will continue to increase,
in proportion as the principles of legislation are
more generally studied and understood. To
suppose the contrary, would reduce us to he
mere spectators of the progress and decline of so¬
ciety, and put an end to every species of pa¬
triotic exertion.
Montesquieu’s own aim in his historical dis¬
quisitions, was obviously much more deep and
refined. In various instances, one would almost
think he had in his mind the very shrewd
aphorism of Lord Coke, that, ££ to trace an
error to its fountain-head, is to refute it—a
species of refutation, which, as Mr Bentham
has well remarked, is, with many understand¬
ings, the only one that has any weight.1 To
men prepossessed with a blind veneration for the
wisdom of antiquity, and strongly impressed
with a conviction that every thing they see
around them is the result of the legislative wis¬
dom of their ancestors, the very existence of a
legal principle, or of an established custom, be¬
comes an argument in its favour; and an argu¬
ment to which no reply can be made, but by
tracing it to some acknowledged prejudice, or to
a form of society so different from that existing
at present, that the same considerations which
serve to account for its first origin, demonstrate
indirectly the expediency of now accommodating
it to the actual circumstances offmankind.
According to this view of the subject, the
speculations of Montesquieu were ultimately
directed to the same practical conclusion with
that pointed out in the prophetic suggestions of
Bacon; aiming, however, at this object, by a
process more circuitous; and, perhaps, on that
account, the more likely to be effectual. The
plans of both have been since combined with
extraordinary sagacity, by some of the later
writers on Political Economy;2 but with their
systems we have no concern in the present sec¬
tion. I shall therefore only remark, in addition
to the foregoing observations, the peculiar utility
of these researches concerning the history of laws,
in repressing the folly of sudden and violent in¬
novation, by illustrating the reference which
laws must necessarily have to the actual circum¬
stances of a people,—and the tendency which
natural causes have to improve gradually and
progressively the condition of mankind, under
every government which allows them to enjoy
the blessings of peace and of liberty.
The well-merited popularity of the Spirit of
Laws, gave the first fatal blow to the study of
Natural Jurisprudence; partly by the proofs
volutions of their monarchy. On many points connected with these researches, his conclusions have been since controverted ;
but all his successors have agreed in acknowledging him as their common master and guide.
1 u Ifour ancestors have been all along mider a mistake, hota came they to have fallen into it ? is a question that naturally
occurs upon all such occasions. The case is, that, in matters of law more especially, such is the dominion of authority over our
minds, and such the prejudice it creates in favour of whatever institution it has taken under its wing, that,” after all
manner of reasons that can be thought of in favour of the institution have been shewn to be insufficient, we still can¬
not forbear looking to some unassignable and latent reason for its efficient cause. But if, instead of any such reason, we
can find a cause for it in some notion, of the erroneousness of which we are already satisfied, then at last we are content
to give it up without farther struggle ; and then, and not till then, our satisfaction is complete.”—Defence of Usury, pp. 94, 95.
2 Above all, by Mr Smith; who, in his Wealth of Nations, has judiciously and skilfully combined with the investigation
of general principles, the most luminous sketches of theoretical history relative to that form of political society which has
given birth to so many of the institutions and customs peculiar to modern Europe.—u The strong ray of philosophic light
on this interesting subject,” which, according to Gibbon, “ broke from Scotland in our times,” was but a reflection, though
with a far steadier and more concentrated force, from the scattered but brilliant sparks kindled by the genius of Montesquieu.
I shall afterwards have occasion to take notice of the mighty influence which his writings have had on the subsequent
history of Scottish literature.
96
PRELIMINARY DISSERTATIONS.
which, in every page, the work afforded, of the
absurdity of all schemes of Universal Legisla¬
tion ; and partly by the attractions which it
possessed, in point of eloquence and taste, when
contrasted with the insupportable dulness of the
systems then in possession of the schools. It is
remarkable, that Montesquieu has never once
mentioned the name of Grotius; in this, pro¬
bably, as in numberless other instances, con¬
ceiving it to he less expedient to attack esta¬
blished prejudices openly and in front, than
gradually to undermine the unsuspected errors
upon which they rest.
If the foregoing details should appear tedious
to some of my readers, I must request them to
recollect, that they relate to a science which,
for much more than a hundred years, constitu¬
ted the whole of philosophy, both ethical and
political, of the largest portion of civilised Eu¬
rope. With respect to Germany, in particu¬
lar, it appears from the Count de Hertzherg,
that this science continued to maintain its un¬
disputed ground, till it was supplanted by that
growing passion for Statistical details, which,
of late, has given a direction so different, and
in some respects so opposite, to the studies of
his countrymen.1
When from Germany we turn our eyes to
the south of Europe, the prospect seems not
merely sterile, hut afflicting and almost hope¬
less. Of Spanish literature I know nothing hut
through the medium of Translations; a very
imperfect one, undoubtedly, when a judgment
is to he passed on compositions addressed to
the powers of imagination and taste; yet fully
sufficient to enable us to form an estimate of
works which treat of science and philosophy.
On such subjects, it may be safely concluded,
that whatever is unfit to stand the test of a literal
version, is not worth the trouble of being studied
in the original. The progress of the Mind in
Spain during the seventeenth century, we may
therefore confidently pronounce, if not entirely
suspended, to have been too inconsiderable to
merit attention.
<c The only good book,” says Montesquieu,
“ which the Spaniards have to boast of, is that
which exposes the absurdity of all the rest.” In
this remark, I have little doubt that there is a
considerable sacrifice of truth to the pointed
effect of an antithesis. The unqualified censure,
at the same time, of this great man, is not un¬
worthy of notice, as a strong expression of his
feelings with respect to the general insignificance
of the Spanish writers.2
The inimitable work here referred to by
Montesquieu, is itself entitled to a place in this
Discourse, not only as one of the happiest and
most wonderful creations of human fancy, but
as the record of a force of character, and an en¬
largement of mind, which, when contrasted with
the prejudices of the author’s age and nation,
seem almost miraculous. It is not merely
against Books of Chivalry that the satire of Cer¬
vantes is directed. Many other follies and ab¬
surdities of a less local and temporary nature
have their share in his ridicule; while not a
single expression escapes his pen that can give
offence to the most fastidious moralist. Hence
those amusing and interesting contrasts by
which Cervantes so powerfully attaches us to
the hero of his story; chastising the wildest
freaks of a disordered imagination, by a stateli¬
ness yet courtesy of virtue, and (on all subjects
but one) by a superiority of good sense and of
philosophical refinement, which, even under the
most ludicrous circumstances, never cease to
   ; |
1 “ La connoissance des dtats qu’on se plait aujourd’hui d’appeller Statistiqiie, est une de ces sciences qui sent devenues
k la mode, et qui ont pris une vogue generale depuis quelques anndes ; elle a presque depossdde celle du Droit Public,
qui regnoit au commencement et jusques vers le milieu du siecle present.”—Reflexions sur la Force des Flats. Par M. le
Comte de Hertzberg. Berlin, 1782.
2 “ Lord Bolingbroke told Mr Spence, as he informs us in his Anecdotes, that Dryden assured him, he was more in¬
debted to the Spanish critics, than to the writers of any other nation.”—(Malone, in a Note on Dryden's Essay on
Dramatic Poesy.
The same anecdote is told, though with a considerable difference in the circumstances, by Warton, in his Essay on
the writings of Pope. “ Lord Bolingbroke assured Pope, that Dryden often declared to him, that he got more from the
Spanish critics, than from the Italian, French, and all other critics put together.”
I suspect that there is some mistake in this story. A Spanish gentleman, equally well acquainted with the literature
of his own country and with that of England, assures me, that he cannot recollect a single Spanish critic from whom
Dryden can reasonably be supposed to have derived any important lights.
DISSERTATION FIRST.
97
command our respect, and to keep alive our
sympathy.
In Italy, notwithstanding the persecution
undergone by Galileo, Physics and Astronomy
continued to be cultivated with success by Tor¬
ricelli, Borelli, Cassini, and others ; and in pure
Geometry, Viviani rose to the very first emi¬
nence, as the Restorer, or rather as the Diviner
of ancient discoveries , but, in all those studies
which require the animating spirit of civil and
religious liberty, this once renowned country
exhibited the most melancholy symptoms of
mental decrepitude. 44 Rome,” says a French
historian, 44 was too much interested in main¬
taining her principles, not to raise every ima¬
ginable barrier against what might destroy them.
Hence that Index of prohibited books, into which
were put the history of the President de Thou ;
the works on the liberties of the Gallican church;
and (who could have believed it?) the transla¬
tions of the Holy Scriptures. Meanwhile, this
tribunal, though always ready to condemn ju¬
dicious authors upon frivolous suspicions of
heresy, approved those seditious and fanatical
theologists, whose writings tended to the en¬
couragement of regicide, and the destruction of
government. The approbation and censure of
books (it is justly added) deserves a place in the
history of the human mind.”
The great glory of the Continent towards the
end of the seventeenth century (I except only the
philosophers of France) was Leibnitz. He was
born as early as 1646, and distinguished him¬
self, while still a very young man, by a display
of those talents which were afterwards to con¬
tend with the united powers of Clarke and of
Newton. I have already introduced his name
among the writers on Natural Law; but, in
every other respect, he ranks more fitly with
the contemporaries of his old age than with
those of his youth. My reasons for thinking so
will appear in the sequel. In the meantime, it
may suffice to remark, that Leibnitz, the Jurist,
belongs to one century, and Leibnitz, the Phi¬
losopher, to another.
In this, and other analogous distributions of
my materials, as well as in the order I have fol¬
lowed in the arrangement of particular facts, it
may be proper, once for all, to observe, that
much must necessarily be left to the discretion¬
ary, though not to the arbitrary decision of the
author’s judgment;—that the dates which sepa¬
rate from each other the different stages in the
progress of Human Reason, do not, like those
which occur in the history of the exact sciences,
admit of being fixed with chronological and in¬
disputable precision; while, in adjusting the
perplexed rights of the innumerable claimants
in this intellectual and shadowy region, a task
is imposed on the writer, resembling not unfre-
quently the labour of him, who should have
attempted to circumscribe, by mathematical
lines, the melting and intermingling colours of
Arachne’s web;
In quo diversi niteant cum mille colores,
Transitus ipse tamen spectantia lumina fallit;
Usque adeo quod tangit idem est, tamen ultima distant.
But I will not add to the number (already
too great) of the foregoing pages, by anticipat¬
ing, and attempting to obviate, the criticisms to
which they may be liable. Nor will I dissem¬
ble the confidence with which, amid a variety
of doubts and misgivings, I look forward to the
candid indulgence of those who are best fitted
to appreciate the difficulties of my undertaking.
I am certainly not prepared to say with John¬
son, that 44 I dismiss my work with frigid in¬
difference, and that to me success and miscar¬
riage are empty sounds.” My feelings are more
in unison with those expressed by the same
writer in the conclusion of the admirable pre¬
face to his edition of Shakspeare. One of his
reflections, more particularly, falls in so com¬
pletely with the train of my own thoughts, that
I cannot forbear, before laying down the pen,
to offer it to the consideration of my readers.
44 Perhaps I may not be more censured for
doing wrong, than for doing little; for raising
in the public, expectations which at last I have
not answered. The expectation of ignorance is
indefinite, and that of knowledge is often tyran¬
nical. It is hard to satisfy those who know not
what to demand, or those who demand by de¬
sign what they think impossible to be done/
]*
DISS. I. PART I.
DISSERTATION FIRST
PART SECOND.
In the farther prosecution of the plan of
which I traced the outline in the Preface to the
First Part of this Dissertation, I find it neces¬
sary to depart considerably from the arrange¬
ment which I adopted in treating of the Phi¬
losophy of the seventeenth century. During
that period, the literary intercourse between the
different nations of Europe was comparatively
so slight, that it seemed advisable to consider,
separately and successively, the progress of the
mind in England, in France, and in Germany.
But from the era at which we are now arrived,
the Republic of Letters may he justly understood
to comprehend, not only these and other coun¬
tries in their neighbourhood, but every region
of the civilised earth. Disregarding, according¬
ly, all diversities of language and of geographi¬
cal situation, I shall direct my attention to the
intellectual progress of the species in general;
enlarging, however, chiefly on the Philosophy
of those parts of Europe, from whence the rays
of science have, in modern times, diverged to
the other quarters of the globe. I propose also,
in consequence of the thickening crowd of useful
authors, keeping pace in their numbers with the
diffusion of knowledge and of liberality, to allot
separate discourses to the history of Metaphysics,
of Ethics, and of Politics; a distribution which,
while it promises a more distinct and connected
view of these different subjects, will furnish con¬
venient resting-places, both to the writer and
to the reader, and can scarcely fail to place, in
a stronger and more concentrated light, what¬
ever general conclusions may occur in the course
of this survey.
The foregoing considerations, combined with
the narrow limits assigned to the sequel of my
work, will sufficiently account for the contract¬
ed scale of some of the following sketches, when
compared with the magnitude of the questions
to which they relate, and the peculiar interest
which they derive from their immediate influ¬
ence on the opinions of our own times.
In the case of Locke and Leibnitz, with whom
the metaphysical history of the eighteenth cen¬
tury opens, I mean to allow myself a greater de¬
gree of latitude. The rank which I have as¬
signed to both in my general plan seems to re¬
quire, of course, a more ample space for their
leading doctrines, as well as for those of some
of their contemporaries and immediate succes¬
sors, than I can spare for metaphysical systems
of a more modern date; and as the rudiments
of the most important of these are to be found
in the speculations either of one or of the other,
I shall endeavour, by connecting with my re¬
view of their works, those longer and more ab¬
stract discussions which are necessary for the
illustration of fundamental principles, to avoid,
as far as possible, in the remaining part of my
discourse, any tedious digressions into the thorny
paths of scholastic controversy. The critical
remarks, accordingly, which I am now to offer
on their philosophical writings, will, I trust.
100
PRELIMINARY DISSERTATIONS.
enable me to execute the very slight sketches
which are to follow, in a manner at once more
easy to myself, and more satisfactory to the hulk
of my readers.
But what I have chiefly in view in these pre¬
liminary observations, is to correct certain mis¬
apprehensions concerning the opinions of Locke
and of Leibnitz, which have misled (with very
few exceptions) all the later historians who
have treated of the literature of the eighteenth
century. I have felt a more particular solici¬
tude to vindicate the fame of Locke, not only
against the censures of his opponents, but against
the mistaken comments and eulogies of his ad¬
mirers, both in England and on the Continent.
Appeals to his authority are so frequent in the
reasonings of all who have since canvassed the
same subjects, that, without a precise idea of
his distinguishing tenets, it is impossible to form
a just estimate, either of the merits or demerits
of his successors. In order to assist my readers
in this previous study, I shall endeavour, as far
as I can, to make Locke his own commentator;
earnestly entreating them, before they proceed
to the sequel of this dissertation, to collate care¬
fully those scattered extracts from his works,
which, in the following section, they will find
brought into contact with each other, with a
view to their mutual illustration. My own con¬
viction, I confess, is, that the Essay on Human
Understanding has been much more generally
applauded than read ; and if I could only flatter
myself with the hope of drawing the atten¬
tion of the public from the glosses of commen¬
tators to the author’s text, I should think that
I had made a considerable step towards the
correction of some radical and prevailing
errors, which the supposed sanction of his
name has hitherto sheltered from a free exami¬
nation.
PROGRESS OF METAPHYSICS DURING THE EIGHTEENTH CENTURY.
SECTION I.
Historical and Critical Review of the Philosophical Works of Locke and Leibnitz.
LOCKE.
Before entering on the subject of this sec¬
tion, it is proper to premise, that, although my
design is to treat separately of Metaphysics,
Ethics, and Politics, it will he impossible to
keep these sciences wholly unmixed in the course
of my reflections. They all run into each other
by insensible gradations; and they have all been
happily united in the comprehensive speculations
of some of the most distinguished writers of the
eighteenth century. The connection between
Metaphysics and Ethics is more peculiarly close ;
the theory of Morals having furnished, ever
since the time of Cud worth, several of the most
abstruse questions which have been agitated
concerning the general principles, both intel¬
lectual and active, of the human frame. The
inseparable affinity, however, between the dif¬
ferent branches of the Philosophy of the Mind,
does not afford any argument against the arrange¬
ment which I have adopted. It only shows,
that it cannot, in every instance, be rigorously
adhered to. It shall be my aim to deviate from
it as seldom, and as slightly, as the miscellaneous
nature of my materials will permit.
John Locke, from the publication of whose
Essay on Human Understanding a new era is to
be dated in the History of Philosophy, was born
at Wrington in Somersetshire, in 1632. Of
DISSERTATION FIRST.
101
his father nothing remarkable is recorded, hut
that he was a captain in the Parliament’s army
during the civil wars; a circumstance which, it
may he presumed from the son’s political opi¬
nions, would not he regarded by him as a stain
on the memory of his parent.
In the earlier part of Mr Locke’s life, he pro¬
secuted for some years, with great ardour, the
study of medicine; an art, however, which he
never actually exercised as a profession. Ac¬
cording to his friend Le Clerc, the delicacy of
his constitution rendered this impossible. But,
that his proficiency in the study was not in¬
considerable, we have good evidence in the de¬
dication prefixed to Dr Sydenham’s Observations
on the History and Cure of Acute Diseases ;x where
he boasts of the approbation bestowed on his
Method by Mr John Locke, who (to borrow
Sydenham’s own words) “ examined it to the
bottom; and who, if we consider his genius and
penetrating and exact judgment, has scarce any
superior, and few equals, now living.” The
merit of this Method, therefore, which still
continues to he regarded as a model by the most
competent judges, may be presumed to have be¬
longed in part to Mr Locke,8—a circumstance
which deserves to be noticed, as an additional
confirmation of what Bacon has so sagaciously
taught, concerning the dependence of all the
sciences relating to the phenomena, either of
Matter or of Mind, on principles and rules de¬
rived from the resources of a higher philosophy.
On the other hand, no science could have been
chosen, more happily calculated than Medicine,
to prepare such a mind as that of Locke for the
prosecution of those speculations which have
immortalised his name; the complicated, and
fugitive, and often equivocal phenomena of dis¬
ease, requiring in the observer a far greater
portion of discriminating sagacity, than those
V1 2 3 of Physics, strictly so called; resembling, in
this respect, much more nearly, the phenomena
about which Metaphysics, Ethics, and Politics,
are conversant.
I have said, that the study of Medicine forms
one of the best preparations for the study of
Mind, to such an understanding as Locke's. To
an understanding less comprehensive, and less
cultivated by a liberal education, the effect of
this study is likely to he similar to what we
may trace in the works of Hartley, Darwin, and
Cabanis; to all of whom we may more or less
apply the sarcasm of Cicero on Aristoxcnus, the
Musician, who attempted to explain the nature
of the soul by comparing it to a Harmony; Hie
AB ARTIFICIO SUO NON RECESSIT.5 In Locke’s
Essay, not a single passage occurs, savouring of
the Anatomical Theatre, or of the Chemical
Laboratory.
In 1666, Mr Locke, then in his thirty-fifth
year, formed an intimate acquaintance with
Lord Ashley, afterwards Earl of Shaftesbury;
from which period a complete change took place,
both in the direction of his studies, and in his
habits of life. His attention appears to have been
then turned, for the first time, to political subj ects:
and his place of residence transferred from the
university to the metropolis. From London (a
scene which gave him access to a society very
different from what he had previously lived in)4
he occasionally passed over to the Continent,
where he had an opportunity of profiting by the
conversation of some of the most distinguished
persons of his age. In the course of his fo¬
reign excursions, he visited France, Germany,
and Holland; but the last of these countries
seems to have been his favourite place of resi¬
dence ; the blessings which the people there en¬
joyed, under a government peculiarly favourable
to civil and religious liberty, amply compensat-
1 Published in the year 1676.
2 It is remarked of Sydenham, by the late Dr John Gregory, “ That though full of hypothetical reasoning, it had not the
usual effect of making him less attentive to observation ; and that his hypotheses seem to have sat so loosely about him,
that either they did not influence his practice at all, or he could easily abandon them, whenever they would not bend to
his experience.” f
This is precisely the idea of Locke concerning the true use of hypotheses. “ Hypotheses, if they are well made, are at
least great helps to the memory, and often direct us to new discoveries.”—Locke’s Works, Vol. III. p. 81- See also some
remarks on the same subject in one of his letters to Mr Molyneux. (The edition of Locke to which I uniformly refer, is
that printed at London in 1812, in Ten Volumes 8vo.)
3 Tusc. Qnaest. Lib. 1. . , , . ,
4 Villiers Duke of Buckingham, and the Lord Halifax, are particularly mentioned among those who were delighted with
his conversation. // r ^7T
102
PRELIMINARY DISSERTATIONS.
mg, in his view, for what their uninviting ter- >
ritory wanted in point of scenery and of climate.
In this respect, the coincidence between the taste
of Locke and that of Descartes throws a pleasing
light on the characters of both.
The plan of the Essay on Human Understanding
is said to have been formed as early as 1670;
bat the various employments and avocations of
the Author prevented him from finishing it till
1687, when he fortunately availed himself of the
leisure which his exile in Holland afforded him,
to complete his long meditated design. He re¬
turned to England soon after the Revolution,
and published the first edition of his work in
1690; the busy and diversified scenes through
which he had passed during its progress, having
probably contributed, not less than the acade¬
mical retirement in which he had spent his
youth, to enhance its peculiar and characte-
ristical merits.
Of the circumstances which gave occasion to
this great and memorable undertaking, the fol¬
lowing interesting account is given in the Pre¬
fatory Epistle to the Reader. “ Five or six
friends, meeting at my chamber, and discoursing
on a subject very remote from this, found them¬
selves quickly at a stand, by the difficulties
that rose on every side. After we had a while
puzzled ourselves, without coming any nearer a
resolution of those doubts which perplexed us,
it came into my thoughts that we took a wrong
course, and that, before we set ourselves upon
inquiries of that nature, it was necessary to ex¬
amine our own abilities, and see what objects
our understandings were, or were not, fitted to
deal with. This I proposed to the company,
who all readily assented, and thereupon it was
agreed, that this should be our first inquiry.
Some hasty and undigested thoughts on a sub¬
ject I had never before considered, which I set
down against our next meeting, gave the first
entrance into this discourse, which having been
thus begun by chance, was continued by en¬
treaty; written by incoherent parcels, and, after
long intervals of neglect, resumed again as my
humour or occasions permitted; and at last in
retirement, where an attendance on my health
gave me leisure, it was brought into that order
thou now seest it.”
Mr Locke afterwards informs us, that “ when
he first put pen to paper, he thought all he
should have to say on this matter would have
been contained in one sheet, but that the far¬
ther he went the larger prospect he had ;—new
discoveries still leading him on, till his book
grew insensibly to the bulk it now appears in.”
On comparing the Essay on Human Under¬
standing with the foregoing account of its origin
and progress, it is curious to observe, that it is
the fourth and last book alone which bears di¬
rectly on the author’s principal object. In this
book, it is further remarkable, that there are
few, if any references to the preceding parts of
the Essay; insomuch that it might have been
published separately, without being less intel¬
ligible than it is. Hence, it seems not unreason¬
able to conjecture, that it was the first part
of the work in the order of composition, and
that it contains those leading and fundamental
thoughts which offered themselves to the au¬
thor’s mind, when he first began to reflect on
the friendly conversation which gave rise to his
philosophical researches. The inquiries in the
first and second books, which are of a much
more abstract, as well as scholastic nature, than
the sequel of the work, probably opened gradu¬
ally on the author’s mind in proportion as he
studied his subject with a closer and more con¬
tinued attention. They relate chiefly to the
origin and to the technical classification of our
ideas, frequently branching out into collateral,
and sometimes into digressive discussions, with¬
out much regard to method or connection. The
third book (by far the most important of the
whole), where the nature, the use, and the abuse
of language are so clearly and happily illustrated,
seems, from Locke’s own account, to have been
a sort of after-thought; and the two excellent
chapters on the Association of Ideas and on En¬
thusiasm (the former of which has contributed,
as much as any thing else in Locke’s writings,
to the subsequent progress of Metaphysical Phi¬
losophy, were printed, for the first time, in the
fourth edition of the Essay.
I would not be understood, by these remarks,
to undervalue the two first books. All that I
have said amounts to this, that the subjects which
they treat of are seldom susceptible of any prac-
DISSERTATION FIRST.
103
tical application to the conduct of the under¬
standing ; and that the author has adopted a new
phraseology of his own, where, in some in¬
stances, he might have much more clearly con¬
veyed his meaning without any departure from
the ordinary forms of speech. But although
these considerations render the two first hooks
inferior in point of general utility to the two
last, they do not materially detract from their
merit, as a precious accession to the theory of
the Human Mind. On the contrary, 1 do not
hesitate to consider them as the richest con¬
tribution of well-observed and well-described
facts, which was ever bequeathed to this branch
of science by a single individual, and as the
indisputable, though not always acknowledged,
source of some of the most refined conclusions,
with respect to the intellectual phenomena, which
have been since brought to light by succeeding
inquirers.
After the details given by Locke himself, of
the circumstances in which his Essay was be¬
gun and completed; more especially, after what
he has stated of the cc discontinued way of writ¬
ing,” imposed on him by the avocations of a
busy and unsettled life, it cannot be thought
surprising, that so very little of method should
appear in the disposition of his materials; or that
the opinions which, on different occasions, he
has pronounced on the same subject, should not
always seem perfectly steady and consistent.
In these last cases, however, I am inclined to
think that the inconsistencies, if duly reflected
on, would be found rather apparent than real.
It is but seldom that a writer possessed of the
powerful and upright mind of Locke, can rea¬
sonably be suspected of stating propositions in
direct contradiction to each other. The pre¬
sumption is, that, in each of these propositions,
there is a mixture of truth, and that the error
lies chiefly in the unqualified manner in which
the truth is stated; proper allowances not being
made, during the fervour of composition, for
the partial survey taken of the objects from a
particular point of view. Perhaps it would not
be going too far to assert, that most of the seem¬
ing contradictions which occur in authors ani¬
mated with a sincere love of truth, might be
fairly accounted for by the different aspects
Avhich the same object presented to them upon
different occasions. In reading such authors,
accordingly, when we meet with discordant ex¬
pressions, instead of indulging ourselves in the
captiousness of verbal criticism, it w ould better
become us carefully and candidly to collate the
questionable passages; and to study so to re¬
concile them by judicious modifications and cor¬
rections, as to render the oversights and mis¬
takes of our illustrious guides subservient to the
precision and soundness of our own conclusions.
In the case of Locke, it must be owned, that this
is not always an easy task, as the limitations of
some of his most exceptionable propositions are
to be collected, not from the context, but from
different and widely separated parts of his
Essay.1 2
In a work thus composed by snatches (to bor¬
row a phrase of the author’s), it was not to be
expected, that he should be able accurately to
draw the line between his own ideas, and the
hints for which he was indebted to others. To
those who are well acquainted with his specula¬
tions, it must appear evident, that he had studied
diligently the metaphysical writings both of
Hobbes and of Gassendi; and that he was no
stranger to the Essays of Montaigne, to the phi¬
losophical works of Bacon, or to Malebranche’s
Inquiry after Truth.9, That he was familiarly
conversant with the Cartesian system may be
presumed from what we are told by his bio-
1 That Locke himself was sensible that some of his expressions required explanation, and was anxious that his opi¬
nions should be judged of rather from the general tone and spirit of his work, than from detached and isolated proposi¬
tions, may be inferred from a passage in one of his notes, where he replies to the animadversions of one of his antagonists
(the Reverend Mr Lowde), who had accused him of calling in question the immutability of moral distinctions. “ But
(says Locke) the good man does well, and as becomes his calling, to be watchful in such points, and to take the alarm, even
at expressions which, standing alone by themselves, might sound ill, and be suspected.”—(Locke’s Works, Vol. II. p. 93.
Note.) . .
2 Mr Addison has remarked, that Malebranche had the start of Locke, by several years, in his notions on the subject of
Duration (Spectator, No. 94.) Some other coincidences, not less remarkable, might be easily pointed out in the opinions
of the English and of the French philosopher.
104
PRELIMINARY DISSERTATIONS.
graplier, that it was this which first inspired him
with a disgust at the jargon of the schools, and
led him into that train of thinking which he after¬
wards prosecuted so successfully. I do not,
however, recollect that he has anywhere in his
Essay mentioned the name of any one of these
authors.1 It is probable, that, when he sat
down to write, he found the result of his youth¬
ful reading so completely identified with the
fruits of his subsequent reflections, that it was
impossible for him to attempt a separation of
the one from the other ; and that he was thus
occasionally led to mistake the treasures of me¬
mory for those of invention. That this was
really the case, may be farther presumed from
the peculiar and original cast of his phraseo-
logy, which, though in general careless and un¬
polished, has always the merit of that charac-
teristical unity and raciness of style, which de¬
monstrate, that, while he was writing, he con¬
ceived himself to be drawing only from his own
resources.
With respect to his style, it may be further ob¬
served, that it resembles that of a well educated
and well informed man of the world, rather than
of a recluse student who had made an object of
the art of composition. It everywhere abounds
with colloquial expressions, which he had pro¬
bably caught by the ear from those whom he
considered as models of good conversation; and
hence, though it now seems somewhat antiqua¬
ted, and not altogether suited to the dignity of
the subject, it may be presumed to have contri¬
buted its share towards his great object of turn¬
ing the thoughts of his contemporaries to logi¬
cal and metaphysical inquiries. The author of
the Characteristics, who will not be accused of
an undue partiality for Locke, acknowledges, in
strong terms, the favourable reception which his
book had met with among the higher classes.
“ I am not sorry, however,” says Shaftesbury,
to one of his correspondents, “ that I lent you
Locke’s Essay, a book that may as well qualify
men for business and the world, as for the sciences
and a university. No one has done more to¬
wards the recalling of philosophy from barbarity,
into use and practice of the world, and into the
company of the better and politer sort, who
might well be ashamed of it in its other dress.
No one has opened a better and clearer way to
reasoning.”2
In a passage of one of Warburton’s letters to
Hurd, which I had occasion to quote in the first
part of this Dissertation, it is stated as a fact,
that, £C when Locke first published his Essay, he
had neither followers nor admirers, and hardly a
single approver.” I cannot help suspecting very
strongly the correctness of this assertion, not
only from the flattering terms in which the Essay
is mentioned by Shaftesbury in the foregoing
quotation, and from the frequent allusions to its
doctrines by Addison and other popular writers
of the same period, but from the unexampled
sale of the book, during the fourteen years
which elapsed between its publication and Locke’s
death. Four editions were printed in the space
of ten years, and three others must have ap¬
peared in the space of the next four; a refer¬
ence being made to the sixth edition by the au¬
thor himself, in the epistle to the reader, prefix¬
ed to all the subsequent impressions. A copy
of the thirteenth edition, printed as early as
1748, is now lying before me. So rapid and so
extensive a circulation of a work, on a subject
so little within the reach of common readers, is
the best proof of the established popularity of
the author’s name, and of the respect generally
entertained for his talents and his opinions.
That the Essay on Human Understanding should
have excited some alarm in the University of
Oxford, was no more than the author had rea¬
son to expect from his boldness as a philosophi¬
cal reformer; from his avowed zeal in the cause
of liberty, both civil and religious; from the
suspected orthodoxy of his Theological Creed;
and (it is but candid to add) from the apparent
1 The name of Hobbes occurs in Mr Locke’s Reply to the Bishop of Worcester. See the Notes on his Essay, B. iv. c. 3.
It is curious that he classes Hobbes and Spinoza together, as writers of the same stamp ; and that he disclaims any intimate
acquaintance with the works of'bither. “ I am not so well read in Hobbes and Spinoza as to be able to say what were their
opinions in this matter, but possibly there be those who will think your Lordship’s authority of more use than those just¬
ly decried names,” &c. &c.
’ See Shaftesbury’s First Letter to a Student at the University.
DISSERTATION FIRST.
105
coincidence of his ethical doctrines with those of
Hobbes.1 It is more difficult to account for the
long continuance, in that illustrious seat of learn¬
ing, of the prejudice against the logic of Locke
(by far the most valuable part of his work), and
of that partiality for the logic of Aristotle, of
which Locke has so fully exposed the futility.
In the University of Cambridge, on the other
hand, the Essay on Human Understanding was,
for many years, regarded with a reverence ap¬
proaching to idolatry; and to the authority of
some distinguished persons connected with that
learned body may be traced (as will afterwards
appear) the origin of the greater part of the ex¬
travagancies which, towards the close of the last
century, were grafted on Locke’s errors, by the
disciples of Hartley, of Law, of Priestley, of
Tooke, and of Darwin.2
To a person who now reads with attention
and candour the work in question, it is much more
easy to enter into the prejudices which at first
opposed themselves to its complete success, than
to conceive how it should so soon have acquired
its just celebrity. Something, I suspect, must
be ascribed to the political importance which Mr
Locke had previously acquired as the champion
of religious toleration; as the great apostle of
the Revolution ; and as the intrepid opposer of
a tyranny which had been recently overthrown.
In Scotland, where the liberal constitution of
the universities has been always peculiarly fa¬
vourable to the diffusion of a free and eclectic
spirit of inquiry, the philosophy of Locke seems
very early to have struck its roots, deeply and
permanently, into a kindly and congenial soil.
Nor were the errors of this great man implicit¬
ly adopted from a blind reverence for his name.
The works of Descartes still continued to be
studied and admired; and the combined systems
of the English and the French metaphysicians
served, in many respects, to correct what was
faulty, and to supply what was deficient, in
each. As to the ethical principles of Locke,
where they appear to lean towards Hobbism,
a powerful antidote against them was already
prepared in the Treatise De Jure Belli et Pads,
which was then universally and deservedly re¬
garded in this country as the best introduction
that had yet appeared to the study of moral
science. If Scotland, at this period, produced
no eminent authors in these branches of learn¬
ing, it was not from want of erudition or of ta¬
lents ; nor yet from the narrowness of mind in¬
cident to the inhabitants of remote and insula¬
ted regions; but from the almost insuperable
difficulty of writing in a dialect, which imposed
upon an author the double task of at once ac¬
quiring a new language, and of unlearning his
own.3 4
The success of Locke’s Essay, in some parts
of the Continent, was equally remarkable;
owing, no doubt, in the first instance, to the
very accurate translation of it into the French
language by Coste, and to the eagerness with
which every thing proceeding from the author of
the Letters m Toleration^ may be presumed to
1 “ It was proposed at a meeting of the heads of houses of the University of Oxford, to censure and discourage the
reading of Locke’s Essay; and, after various debates among themselves, it was concluded, that each head of a house
should endeavour to prevent its being read in his college, without coming to any public censure.”—(See Des Maizeaux’s
note on a letter from Locke to Collins—Locke’s Works, Vol. X. p. 284.
* I have taken notice, with due praise, in the former part of this discourse, of the metaphysical speculations of John
Smith, Henry More, and Ralph Cudworth ; all of them members and ornaments of the University of Cambridge about
the middle of the seventeeth century. They were deeply conversant in the Platonic Philosophy, and applied it with great
success in combating the Materialists and Necessitarians of their times. They carried, indeed, some of their Platonic no¬
tions to an excess bordering on mysticism, and may, perhaps, have contributed to give a bias to some of their academical
successors towards the opposite extreme. A very pleasing and interesting account of the characters of these amiable and
ingenious men, and of the spirit of their philosophy, is given by Burnet in the History of his Own Times.
To the credit of Smith and of More it may be added, that they were among the first in England to perceive and to
acknowledge the merits of the Cartesian Metaphysics.
3 Note S.
4 The principle of religious toleration was at that time very imperfectly admitted, even by those philosophers who
were the most zealously attached to the cause of civil liberty. The great Scottish lawyer and statesman, Lord Stair,
himself no mean philosopher, and, like Locke, a warm partizan of the Revolution, seems evidently to have regretted the
impunity which Spinoza had experienced in Holland, and Hobbes in England. “ Execrabilis ille Atheus Spinosa adeo
impudens est, ut affirmet omnia esse absolute necessaria, et nihil quod est, fuit, aut erit, aliter fieri potuisse, in quo omnes
superiores Atheos excessit, aperte negans omnem Deitatem, nihilque pneter potentias natune agnoscens.
“ Vaninus Deitatem non aperte negavit, sed causam illius prodidit, in tractatu quem edidit, argumenta pro Dei existen-
tia tanquam futilia et vana rejiciens, adferendo contrarias omnes rationes per modum objectionum, easque prosequendo ut
DISS. I. PART II. O
106
PRELIMINARY DISSERTATIONS.
have been read by the multitude of learned and
enlightened refugees, whom the revocation of
the edict of Nantz forced to seek an asylum in
Protestant countries. In Holland, where Locke
was personally known to the most distinguish¬
ed characters, both literary and political, his
work was read and praised by a discerning few,
with all the partiality of friendship;1 but it does
not seem to have made its way into the schools
till a period considerably later. The doctrines
of Descartes, at first so vehemently opposed in
that country, were now so completely triumph¬
ant, both among philosophers and divines,2 that
it was difficult for a new reformer to obtain a
hearing. The case was very nearly similar in
Germany, where Leibnitz (who always speaks
coldly of Locke’s Essay)5 was then looked up
to as the great oracle in every branch of learn¬
ing and of science. If I am not mistaken, it
was in Switzerland, where (as Gibbon observes)
“ the intermixture of sects had rendered the
clergy acute and learned on controversial topics,”
that Locke’s real merits were first appreciated
on the Continent with a discriminating impartia¬
lity. In Crousaz’s Treatise of Logic (a book
which, if not distinguished by originality of ge¬
nius, is at least strongly marked with the sound
and unprejudiced judgment of the author), we
everywhere trace the influence of Locke’s doc¬
trines ; and, at the same time, the effects of the
Cartesian Metaphysics, in limiting those hasty
expressions of Locke, which have been so often
misinterpreted by his followers.4 Nor do Crou¬
saz’s academical labours appear to have been less
indissolubiles videantur; postea tamen larvam exult, et atheismum clare professus est, et justissime in inclyta urbe
ThOEOSA DAMNATUS E8T ET CREMATES.
“ Horrendus Hobbesius tertius erat atheismi promotor, qui omnia principia moralia et politica subvertit, eorumque
ioco naturaiem vim et humana pacta, ut prima principia moralitatis, societatis, et politic! regiminis substituit: nec ta¬
mer Spirosa aut Hobbies, cieamvis ir regioribes reeormatis vixerirt et mortei sirt, redem exempla
FACTI SERT IR ATHEOREM TERROREM, ET RE VEL EEEAM P-®RAM SERSERIRT.” (Physiol. Nova ExperimentallS. Lugd.
Batav. 16G6, pp. 16, 17-)
1 Among those whose society Locke chiefly cultivated while in Holland, was the celebrated Le Clerc, the author of the
BiUiotheque Universelle, and the BiUiutheque Choisie, besides many other learned and ingenious publications. He appears to
have been warmly attached to Locke, and embraced the fundamental doctrines of his Essay without any slavish deference
for his authority. Though he fixed his residence at Amsterdam, where he taught Philosophy and the Belles Lettres, he
was a native of Geneva, where he also received his academical education. He is, therefore, to be numbered with Locke’s
Swiss disciples. I shall have occasion to speak of him more at length afterwards, when I come to mention his controversy
with Bayle. At present, I shall only observe, that his Eloge on Locke was published in the Biblioth&que Choisie (Anne'e
1705,) Tom. VI.; and that some important remarks on the Essay on Human Understanding, particularly on the chapter on
Power, are to be found in the 12th Vol. of the same work (Anne'e 1707-)
2 Quamvis huic sec tie (Cartesiame) initio acriter se opponerent Theologi et Philosophi Belgse, in Academiis tamen
eorum hodie (1727,) vix alia, quam Cartesiana principia inculcantur—(Heireccii Elem. Hist. Philosoph.) In Gravesande’s
Introductio ad Philosophiam. published in 1736, the name of Locke is not once mentioned. It is probable that this last au¬
thor was partly influenced by his admiration for Leibnitz, whom he servilely followed even in his physical errors.
s In Lockio sunt qusedam particularia non male exposita, sed in summa longe aberravit a janua, nec naturam mentis
veritatisque intellexit—(Leibritz. Op. Tom. V. p. 355. ed. Dutens.)
M. Locke avoit de la subtilite et de Paddresse, et quelque espece de metaphysique superficielle qu’il savoit relever—
{Hid. pp. 11, 12.)
Heineccius, a native of Saxony, in a Sketch of the History of Philosophy, printed in 1728, omits altogether the name of
Locke in his enumeration of the logical and metaphysical writers of modern Europe. In a passage of his logic, where
the same author treats of clear and obscure, adequate and inadequate ideas (a subject on which little or nothing of any value
had been advanced before Locke), he observes, in a note, “ Debemus hanc Doctrinam Leibnitio, eamque deinde sequutus
est illust. Wolfius.”
4 Of the Essay on Human Understanding Crousaz speaks m the following terms : “ Clarissimi, et merito celebratissimi
Lockii de Intellectu Humano eximium opus, et auctore suo dignissimum, logicis utilissimis semper annumerabitur.”—
{Prcefat.) If Pope had ever looked into this Treatise, he could not have committed so gross a mistake, as to introduce
the author into the Dunciad, among Locke’s Aristotelian opponents; a distinction for which Crousaz was probably indebted
to his acute strictures on those passages in the Essay on Man, which seem favourable to fatalism.
Prompt at the call, around the goddess roll
Broad hats, and hoods, and caps, a sable shoal;
Thick and more thick the black blockade extends,
A hundred head of Aristotle’s friends.
Nor wert thou, Isis ! wanting to the day
(Though Christ-church long kept prudishly away).
Each staunch Polemic, stubborn as a rock,
Each fierce Logician, still expelling Locke,
Came whip and spur, and dash’d through thm and thick
On German Crousaz, and Dutch Burgersdyck.
Warburton, with his usual scurrility towards all Pope’s adversaries as well as his own, has called Crousaz a blundering
Swiss ; but a very different estimate of his merits has been formed by Gibbon, who seems to have studied his works much
more carefully than the Right Reverend Commentator on the Dunciad.
“ M. de Crousaz, the adversary of Bayle and Pope, is not distinguished by lively fancy or profound reflection ; and
DISSERTATION FIRST.
107
useful than his writings; if a judgment on this
point may be formed from the sound philosophi¬
cal principles which he diffused among a nume¬
rous race of pupils. One of these (M. Alla-
mand), the friend and correspondent of Gibbon,
deserves particularly to be noticed here, on ac¬
count of two letters published in the posthumous
works of that historian, containing a criticism
on Locke’s argument against innate ideas, so very
able and judicious, that it may still be read with
advantage by many logicians of no small note
in the learned world. Had these letters hap¬
pened to have sooner attracted my attention, I
should not have delayed so long to do this tardy
j ustice to their merits.1
I am not able to speak with confidence of the
period at which Locke’s Essay began to attract
public notice in France. Voltaire, in a letter to
Horace Walpole, asserts, that he was the first
person who made the name of Locke known to
his countrymen ;2 but I suspect that this asser¬
tion must be received with considerable quali¬
fications. The striking coincidence between
some of Locke’s most celebrated doctrines and
those of Gassendi, can scarcely be supposed to
have been altogether overlooked by the followers
and admirers of the latter ; considering the im¬
mediate and very general circulation given on the
Continent to the Essay on Human Understanding,
by Coste’s French version. The Gassendists, too,
it must be remembered, formed, even before
the death of their master, a party formidable in
talents as well as in numbers; including, among
other distinguished names, those of Moliere,5
even in his own country, at the end of a few years, his name and writings are almost obliterated. But his Philosophy had
been formed in the school of Locke, his Divinity in that of Limborch and Le Clerc; in a long and laborious life, several
generations of pupils were taught to think, and even to write ; his lessons rescued the Academy of Lausanne from Cal-
vinistic prejudices ; and he had the rare merit of diffusing a more liberal spirit among the people of the Pays de Vaud."—
(Gibbon’s Memoirs^)
In a subsequent passage Gibbon says, “ the logic of Crousaz had prepared me to engage with his master Locke, and his
antagonist Bayle ; of whom the former may be used as a bridle, and the latter applied as a spur to the curiosity of a young
philosopher.”—(IUd.)
The following details, independently of their reference to Crousaz, are so interesting in themselves, and afford so strong
a testimony to the utility of logical studies, when rationally conducted, that I am tempted to transcribe them.
“ December 1755. In finishing this year, I must remark how favourable it was to my studies. In the space of eight
months, I learned the principles of drawing; made myself completely master of the French and Latin languages, with
which I was very superficially acquainted before, and wrote and translated a great deal in both ; read Cicero’s Epistles ad
Familiares, his Brutus, all his Orations, his Dialogues de Amicitia et de Senectute; Terence twice, and Pliny’s Epistles.
In French, Giannoni’s History of Naples, 1’Abbe Barrier’s Mythology, and M. Iloehat’s Memoires sur la Suisse, and wrote
a very ample relation of my tour. I likewise began to study Greek, and went through the grammar. I began to make
very large collections of what I read. But what I esteem most of all,—from the perusal and meditation of De Crousaz’s
logic, I not only understood the principles of that science, but formed my mind to a habit of thinking and reasoning, I had
no idea of before.”
After all, I very readily grant, that Crousaz’s logic is chiefly to be regarded as the work of a sagacious and enlightened
compiler; but even this (due allowance being made for the state of philosophy when it appeared) is no mean praise.
“ Good sense (as Gibbon has very truly observed) is a quality of mind hardly less rare than genius.”
1 For some remarks of M. Allamand, which approach very near to Reid’s Objections to the Ideal Theory, See Note T.
Of this extraordinary man Gibbon gives the following account in his Journal; “ C’est un ministre dans le Pays de Vaud,
et un des plus beaux genies que je connoisse. II a voulu embrasser tous les genres ; mais c’est la. Philosophic qu’il a le
plus approfondi. Sur toutes les questions il s’est fait des systemes, ou du moins des argumens toujours originaux et tou-
jours ingenieux. Ses idees sont fines et lumineuses, son expression heureuse et facile. On lui reproche avec raison
trop de rafinement et de subtilitd dans 1’esprit; trop de fierte, trop d’ambition, et trop de violence dans le caractere. Cet
homme, qui auroit pu eclairer ou troubler une nation, vit et mourra dans 1’obscurite'.”
It is of the same person that Gibbon sneeringly says, in the words of Vossius, “ Est sacrificulus in pago, et rusticos
decipit.”
2 “ Je peux vous assurer qu’avant moi personne en France ne connoissoit la poesie Angloise; h peine avoit on entendu
parler de Locke. J’ai e'te' persecute' pendant trente ans par une nude de fanatiques pour avoir dit que Locke est 1’Her-
cule de la Metaphysique, qui a pose les bornes de I’Esprit Humain.”—(Ferney, 1768.)
In the following passage of the Age of Louis XIV. the same celebrated writer is so lavish and undistinguishing in his
praise of Locke, as almost to justify a doubt whether he had ever read the book which he extols so highly. “ Locke seul
a developpd Ventendement humain, dans un livre oil il n’y a que des veritds; et ce qui rend 1’ouvrage parfait, toutes ces
verites sont claires.”
3 Moliere was in his youth so strongly attached to the Epicurean theories, that he had projected a translation of Lu¬
cretius into French. He is even said to have made some progress in executing his design, when a trifling accident de¬
termined him, in a moment of ill humour, to throw his manuscript into the fire. The plan on which he was to proceed in
this bold undertaking does honour to his good sense and good taste, and seems to me the only one on.which a successful
version of Lucretius can ever be executed. The didactic passages of the poem were to be translated into prose, and. the
descriptive passages into verse. Both paxts would have gained greatly by this compromise; for, where Lucretius wishes
to unfold the philosophy of his master, he is not less admirable for the perspicuity and precision of his expressions, than
he is on other occasions, where his object is to detain and delight the imaginations of his readers, for the charms of his
figurative diction, and for the bold relief of his images. In instances of the former kind, no modern language can give
108
PRELIMINARY DISSERTATIONS.
Chapelle,1 and Bernier;* all of them eminent¬
ly calculated to give the tone, on disputed ques¬
tions of Metaphysics, to that numerous class of
Parisians of both sexes, with whom the practical
lessons, vulgarly imputed to Epicurus, were not
likely to operate to the prejudice of his specu¬
lative principles. Of the three persons just men¬
tioned, the two last died only a few years before
Locke’s Essay was published; and may be pre¬
sumed to have left behind them many younger
pupils of the same school. One thing is certain,
that, long before the middle of the last century,
the Essay on Human Understanding was not only
read by the learned, but had made its way into
the circles of fashion at Paris.3 In what man¬
ner this is to be accounted for, it is not easy
to say; but the fact will not be disputed by
those who are at all acquainted with the his¬
tory of French literature.
In consequence of this rapid and extensive
circulation of the work in question, and the
strong impression that it everywhere produced,
by the new and striking contrast which it ex¬
hibited to the doctrines of the schools, a very re¬
markable change soon manifested itself in the
prevailing habits of thinking on philosophical
subjects. Not that it is to be supposed that the
opinions of men, on particular articles of their
former creed, underwent a sudden alteration. I
speak only of the general effect of Locke’s dis¬
cussions, in preparing the thinking part of his
readers, to a degree till then unknown, for the
unshackled use of their own reason. This has
always appeared to me the most characteristical
feature of Locke’s Essay; and that to which it is
chiefly indebted for its immense influence on the
philosophy of the eighteenth century. Few books
can be named, from which it is possible to ex¬
tract more exceptionable passages; but, such is
the liberal tone of the author; such the man¬
liness with which he constantly appeals to reason,
as the paramount authority which, even in re¬
ligious controversy, every candid disputant is
bound to acknowledge; and such the sincerity
and simplicity with which, on all occasions, he
appears to inquire after truth, that the general
effect of the whole work may be regarded as the
best of all antidotes against the errors involved in
some of its particular conclusions.4
To attempt any general review of the doctrines
even the semblance of poetry to the theories of Epicurus ; while, at the same time, in the vain attempt to conquer this dif¬
ficulty, the rigorous precision and simplicity of the original are inevitably lost.
The influence of Gassendi’s instructions may be traced in several of Moliere’s comedies; particularly in the Femmes
Savantes, and in a little piece Le Mariage Force, where an Aristotelian and a Cartesian doctor are both held up to the same
sort of ridicule, which, in some other of his performances, he has so lavishly bestowed on the medical professors of his time.
1 The joint author, with Bachaumont, of the Voyage en Provence, which is still regarded as the most perfect model of
that light, easy, and graceful badinage which seems to belong exclusively to French poetry. Gassendi, who was an in¬
timate friend of his father, was so charmed with his vivacity while a boy, that he condescended to be his instructor in phi¬
losophy; admitting, at the same time, to his lessons, two other illustrious pupils, Moliere and Bernier. I he life of Cha¬
pelle, according to all his biographers, exhibited a complete contrast to the simple and ascetic manners of his master; but,
if the following account is to be credited, he missed no opportunity of propagating, as widely as he could, the speculative
principles in which he had been educated. “ II dtoit fort eloquent dans 1’ivresse. II restoit ordinairement le dernier a
table, et se mettoit a expliquer aux valets la philosophie d’Epicure.”—(Biographic Universelle, article Chapelle, Paris,
1813.) He died in 1686.
2 The well known author of one of our most interesting and instructive books of travels. After his return from the
East, where he resided twelve years at the court of the Great Mogul, he published at Lyons, an excellent Abridgment of
the Philosophy of Gassendi, in 8 vols. 12mo; a second edition of which, corrected by himself, afterwards appeared, in seven
volumes. To this second edition (which I have never met with) is annexed a Supplement, entitled Doutes de M. Bernier
sur quelques uns des principaux Chapitres de son Abrege de la Philosophie de Gassendi. It is to this work, I presume, that
Leibnitz alludes in the following passage of a letter to John Bernouilli; and, from the manner in which he speaks of its
contents, it would seem to be an object of some curiosity. “ Frustra qusesivi apud typographos librum cui titulus ;
Doutes de M. Bernier sur la Philosophie, in Gallia ante annos aliquot editum et mihi visum, sed nunc non repertum. Vel-
lem autem ideo iterupi legere, quia ille Gassendistorum fuit Princeps; sed paullo ante mortem, libello hoc edito ingenue
professus est, in quibus necGassendus nee Cartesius satisfaciant.”—(Leibnitii et Jo. Bernouilli Commerc. Epist. 2 voL
4to. Laussanse et Genevas, 1745.)
Bernier died in 1688.
3 A decisive proof of this is afforded by the allusions to Locke’s doctrines in the dramatic pieces then in possession of
the French stage. See Note U.
4 The maxim which he constantly inculcates is, that “ Reason must be our last judge and guide in every thing.”—
(Locke’s Works, Vol. III. p. 145.) To the same purpose, he eisew'here observes, that “ he who makes use of the light
and faculties God has given him, and seeks sincerely to discover truth by those helps and abilities he has, may have this
satisfaction in doing his duty as a rational creature; that, though he should miss truth, he will not miss the reward of it-
For he governs his assent right, and places it as he should, wrho in any case or matter whatsoever, believes or disbelieves,
according as reason directs him. He that does otherwise, transgresses against his own light, and misuses those faculties
which were given him to no other end, but to search and follow the clearer evidence and greater probability.”—-(Ibid. p. 125.)
DISSERTATION FIRST.
109
sanctioned, or supposed to be sanctioned, by the
name of Locke, would be obviously incompatible
with the design of this Discourse; but, among
these doctrines, there are two, of fundamental
importance, which have misled so many of his
successors, that a few remarks on each form a
necessary preparation for some historical details
which will afterwards occur. The first of these
doctrines relates to the origin of our ideas;
the second to the power of moral perception,
AND THE IMMUTABILITY OF MORAL DISTINC¬
TIONS. On both questions, the real opinion of
Locke has, if I am not widely mistaken, been
very grossly misapprehended or misrepresented,
by a large portion of his professed followers, as
well as of his avowed antagonists.
1. The objections to which Locke’s doctrine
concerning the origin of our ideas, or, in other
words, concerning the sources of our knowledge,
are, in my judgment, liable, I have stated so
fully in a former work,1 that I shall not touch
on them here. It is quite sufficient, on the pre¬
sent occasion, to remark, how very unjustly this
doctrine (imperfect, on the most favourable con¬
struction, as it undoubtedly is) has been con¬
founded with those of Gassendi, of Condillac, of
Diderot, and of Horne Tooke. The substance
of all that is common in the conclusions of these
last writers, cannot be better expressed than in
the words of their Master, Gassendi. “ All our
knowledge (he observes in a letter to Descartes)
appears plainly to derive its origin from the
senses; and although you deny the maxim,
6 Quicquid est in intellectu praeesse debere in
sensu,’ yet this maxim appears, nevertheless, to
be true; since our knowledge is all ultimately
obtained by an influx or incursion from things
external; which knowledge afterwards under¬
goes various modifications by means of analogy,
composition, division, amplification, extenuation,
and other similar processes, which it is un¬
necessary to enumerate.”*
This doctrine of Gassendi’s coincides exactly
with that ascribed to Locke by Diderot and by
Horne Tooke; and it differs only verbally from
the more concise statement of Condillac, that
“ our ideas are nothing more than transformed
sensations.” “ Every idea,” says the first of
these writers, “ must necessarily, when brought
to its state of ultimate decomposition, resolve it¬
self into a sensible representation or picture; and
since every thing in our understanding has been
introduced there by the channel of sensation,
whatever proceeds out of the understanding is
either chimerical, or must be able, in returning
by the same road, to re-attach itself to its sensible
archetype. Hence an important rule in phi¬
losophy,—that every expression which cannot
find an external and a sensible object, to which
1 Philosophical Essays.
2 “ Deinde oinnis nostra notitia videtur plane ducere originem asensibus ; et quamvis tu neges quicquid est in intellectu
praeesse debere in sensu, videtur id esse nihilominus vermn, cum nisi sola incursione vigiTTramv, ut loquuntur, fiat; per-
ficiatur tamen analogia, compositione, divisione, ampliatione, extenuatione, aliisque similibus modis, quos commemorare nihil
est necesse.”—( Objectiones in Meditationem Sccundam.)
This doctrine of Gassendi’s is thus very clearly stated and illustrated, by the judicious authors of the Port Royal Logic:
“ Un philosophe qui est estime dans le monde commence sa logique par cette proposition : Omnis idea orsum ducit a sensibus.
Toute idee tire son origine des sens. II avoue neanmoins que toutes nos iddes n’ont pas e'te dans nos sens telles qu’elles sont
dans notre esprit: mais il pretend qu’elles ont au moins etd formdes de celles qui ont passe par nos sens, ou par composition,
comme lorsque des images separees de 1’or et d’une montagne, on s’en fait une montagne d’or; ou par ampliation et diminu¬
tion, comme lorsque de i’image d’un homme d’une grandeur ordinaire on s’en forme un geant ou un pigmde; ou par ac¬
commodation et proportion, comme lorsque de Tidee d’une maison qu’on a vue, on s’en forme I’image d’une maison qu’on n’a
pas vue. Et ainsi, dit il, nous concevons Dieu aui ne peut tomber sous i.es sens, sous l’xmage d’un vene¬
rable vieillard.” “ Selon cette pensee, quoique toutes nos idees ne fussent semblables a quelque corps particulier que
nous ayons vu, ou qui ait frappe nos sens, elles seroient neanmoins toutes corporelles, et ne vous representeroient rien qui
ne fut entre dans nos sens, au moins par parties. Et ainsi nous ne concevons rien que par des images, semblables a celles
qui se forment dans les cerveau quand nous voyons, ou nous nous imaginons des corps.”—{L'Art de Penser, 1 Partie. c. 1.)
The reference made, in the foregoing quotation, to Gassendi’s illustration drawn from the idea of God, affords me an
opportunity, of which I gladly avail myself, to contrast it with Locke’s opinion on the same subject. “ How many amongst
us will be found, upon inquiry, to fancy God, in the shape of a man, sitting in heaven, and to have many other absurd and
unfit conceptions of him ? Christians, as well as Turks, have had whole sects owning, or contending earnestly for it, that
the Deity was corporeal and of human shape : And although we find few amongst us, who profess themselves Anthropomor-
phites (though some I have met with that own it), yet, I believe, he that will make it his business, may find amongst the
ignorant and uninstructed Christians, many of that opinion.” ^—(Vol. I. p. 67.)
* In the judgment of a very learned and pious divine, the bias towards Anthropomorphism, which Mr Locke has here so
severely reprehended, is not confined to “ ignorant and uninstructed Christians.” “ If Anthropomorphism (says Dr Maclaine)
was banished from theology, orthodoxy would be deprived of some of its most precious phrases, and our confessions of faith
110
PRELIMINARY DISSERTATIONS.
it can thus establish its affinity, is destitute of
signification.”—{Oeuvres de Diderot, Tom. VI.)
Such is the exposition given by Diderot, of
what is regarded in France as Locke’s great
and capital discovery ; and precisely to the same
purpose we are told by Condorcet, that “ Locke
was the first who proved that ad our ideas are
compounded of sensations.,,—{Esquisse Historique,
&c.)
If this were to be admitted as a fair account
of Locke’s opinion, it would follow, that he has
not advanced a single step beyond Gassendi and
Hobbes; both of whom have repeatedly expressed
themselves in nearly the same words with Di¬
derot and Condorcet. But although it must be
granted, in favour of their interpretation of his
language, that various detached passages may
be quoted from his work, which seem, on a
superficial view, to justify their comments, yet
of what weight, it may be asked, are these pas¬
sages, when compared with the stress laid by
the author on Reflection, as an original source of
our ideas, altogether different from Sensation ?
“ The other fountain,” says Locke, “ from which
experience furnisheth the understanding with
ideas, is the perception of the operations of our
own minds within us, as it is employed about
the ideas it has got; which operations, when the
soul comes to reflect on and consider, do furnish
the understanding with another set of ideas,
which could not be had from things without;
and such are Perception, Thinking, Doubting, Be-
“ Let the ideas of being and matter be strongly joined either by education or much thought, whilst these are still com¬
bined in the mind, what notions, what reasonings will there be about separate spirits ? Let custom, from the very childhood,
have joined figure and shape to the idea of God, and what absurdities will that mind be liable to about the Deity ?”—(Yol.
II. p. 144.)
The authors of the Port Royal Logic have expressed themselves on this point to the very same purpose with Locke; and
have enlarged upon it still more fully and forcibly. (See the sequel of the passage above quoted.) Some of their remarks on
the subject, which are more particularly directed against Gassendi, have led Brucker to rank them among the advocates for
innate ideas (Brucker, Historia de I dels, p. 271), although these remarks coincide exactly in substance with the foregoing quo¬
tation from Locke. Like many other modern metaphysicians, this learned and laborious, but not very acute historian,
could imagine no intermediate opinion between the theory of innate ideas, as taught by the Cartesians, and the Epicurean
account of our knowledge, as revived by Gassendi and Hobbes ; and accordingly thought himself entitled to conclude, that
whoever rejected the one must necessarily have adopted the other. The doctrines of Locke and of his predecessor Arnauld
will be found, on examination, essentially different from both.
Persons little acquainted with the metaphysical speculations of the two last centuries are apt to imagine, that when “ all
knowledge is said to have its origin in the senses,” nothing more is to be understood than this, that it is by the impressions
of external objects on our organs of perception, that the dormant powers of the understanding are at first awakened. The
foregoing quotation from Gassendi, together with those which I am about to produce from Diderot and Condorcet, may, I
trust, be useful in correcting this very common mistake; allot* these quotations explicitly asserting, that the external senses
furnish not only the occasions by which our intellectual powers are excited and developed, but all the materials dbout which
our thoughts are conversant; or, in other words, that it is impossible for us to think of anything, which is not either a
sensible image, or the result of sensible images combined together, and transmuted into new forms by a sort of logical che¬
mistry. That the powers of the understanding would for ever continue dormant, were it not for the action of things ex¬
ternal on the bodily frame, is a proposition now universally admitted by philosophers. Even Mr Harris and Lord Mon-
boddo, the two most zealous, as well as most learned of Mr Locke’s adversaries in England, have, in the most explicit man¬
ner, expressed their assent to the common doctrine. “ The first class of ideas (says Monboddo) is produced from ideas fur¬
nished by the senses ; the second arises from the operations of the mind upon these materials: for I do not deny, that in
this our present state of existence, all our ideas, and all our knowledge, are ultimately to be derived from sense and matter.”
(Vol. I. p. 44. 2d Ed.) Mr Harris, while he holds the same language, points out, with greater precision, the essential dif¬
ference between his philosophy and that of the Hobbists. “ Though sensible objects may be the destined medium to awa¬
ken the dormant energies of man’s understanding, yet are those energies themselves no more contained in sense, than the
explosion of a cannon in the spark which gave it fire.”—(Hermes.) On this subject see Elements of the Philosophy of the
Human Mind, Vol. I. chap. i. sect. 4.
To this doctrine I have little doubt that Descartes himself would have assented, although the contrary opinion has been
generally supposed by his adversaries to be virtually involved in his Theory of Innate Ideas. My reasons for thinking so,
the reader will find stated in Note X.
and systems of doctrine would be reduced within much narrower bounds.”—(Note on Mosheim’s Church History, Vol. IV.
p. 550.)
On this point I do not presume to offer any opinion ; but one thing I consider as indisputable, that it is by means of
Anthropomorphism, and other idolatrous pictures of the invisible world, that superstition lays hold of the infant mind.
Such pictures operate not upon Reason, but upon the Imagination; producing that temporary belief with which I conceive
all the illusions of imagination to be accompanied.
In point of fact, the bias of which Locke speaks extends in a greater or less degree to all men of strong imaginations,
whose education has not been very carefully superintended in early infancy.
I have applied to Anthropomorphism the epithet idolatrous, as it seems to be essentially the same thing to bow down and
worship a graven image of the Supreme Being, and to worship a supposed h’keness of Him conceived by the Imagination.
In Bernier’s Abridgment of Gassendi's Philosophy (Tom. III. p. 13 el seq.) an attempt is made to reconcile with the Epi¬
curean account of the origin of our knowledge, that more pure and exalted idea of God to which the mind is gradually led
by the exercise of its reasoning powers : But I am very doubtful, if Gassendi would have subscribed, in this instance, to
the comments of his ingenious disciple.
DISSERTATION FIRST.
Ill
lleving, Reasoning, Knowing, Willing, and all the
different actings of our own minds, which, we
being conscious of, and observing in ourselves,
do from these receive into our understandings
ideas as distinct as we do from bodies affecting
our senses. This source of ideas every man has
wholly in himself: And though it be not sense,
as having nothing to do with external objects, yet it
is very like it, and might properly enough be
called internal sense. But as I call the other
Sensation, so I call this Reflection ; the ideas
it affords being such only as the mind gets by
rejlecting on its own operations within itself.”1 2
—(Locke’s Works, Vol. I. p. 78.)
“ The understanding seems to me not to have
the least glimmering of any ideas which it doth
not receive from one of these two. External
objects furnish the mind with the ideas of sensible
qualities ; and the mind furnishes the understand¬
ing with ideas of its own operations.,,—(Ibid.
p. 79.)
In another part of the same chapter, Locke
expresses himself thus : “ Men come to he fur¬
nished with fewer or more simple ideas from
without, according as the objects they converse
with afford greater or less variety; and from the
operations of their minds within, according as
they more or less reflect on them. For,
though he that contemplates the operations of
his mind, cannot but have plain and clear ideas
of them; yet, unless he turn his thoughts that
way, and consider them attentively, he will no
more have clear and distinct ideas of all the ope¬
rations of his mind, and all that may be ob¬
served therein, than he will have all the parti¬
cular ideas of any landscape, or of the parts and
motions of a clock, who will not turn his eyes
to it, and with attention heed all the parts of it.
The picture, or clock, may be so placed, that
they may come in his way every day; hut yet
he will have but a confused idea of all the parts
they are made up of, till he applies himself with
attention to consider them in each particular.
“ And hence we see the reason why it is
pretty late before most children get ideas of the
operations of their own minds; and some have
not any very clear or perfect ideas of the great¬
est part of them all their lives Children,
when they first come into it, are surrounded
with a world of new things, which, by a con¬
stant solicitation of their senses, draw the mind
constantly to them,—forward to take notice of
new, and apt to he delighted with the variety of
changing objects. Thus, the first years are
usually employed and directed in looking abroad.
Men’s business in them is to acquaint themselves
with what is to he found without; and so grow¬
ing up in a constant attention to outward sensa¬
tions, seldom make any considerable reflection on
what passes within them, till they come to be
of riper years; and some scarce ever at all.”—
(Ibid. pp. 80. 81.)
I beg leave to request more particularly the
attention of my readers to the following pa¬
ragraphs :
<c If it be demanded, when a man begins to have
any ideas ? I think the true answer is, when
he first has any sensation I conceive that
ideas in the understanding are coeval with sen¬
sation ; which is such an impression or motion,
made in some part of the body, as produces some
perception in the understanding. It is about
these impressions made on our senses by out¬
ward objects, that the mind seems first to em¬
ploy itself in such operations as we call Percep¬
tion, Remembering, Consideration, Reasoning, &c.
<c In time, the mind comes to reflect on its
own operations, and about the ideas got by sen¬
sation, and thereby stores itself with a new set
of ideas, which I call ideas of refection. These
impressions that are made on our senses by ob¬
jects extrinsical to the mind; and its own opera¬
tions, proceeding from powers intrinsical and pro¬
per io itself (which, when reflected on by itself,
become also objects of its contemplation), are,
as I have said, the original of all knowledge.”*—
(Ibid. pp. 91. 92.)
A few other scattered sentences, collected
1 Note Y.
2 The idea attached by Locke in the above passages to the word Reflection is clear and precise. But in the course of his
subsequent speculations, he does not always rigidly adhere to it, frequently employing it in that more extensive and popu¬
lar sense in which it denotes the attentive and deliberate consideration of any object of thought, whether relating to the ex-
112
PRELIMINARY DISSERTATIONS.
from different parts of Locke’s Essay, may throw
additional light on the point in question.
“ I know that people, whose thoughts are im¬
mersed in matter, and have so subjected their
minds to their senses, that they seldom reflect on
anything beyond them, are apt to say, they can¬
not comprehend a thinking thing, which perhaps
is true: But I affirm, when they consider it
well, they can no more comprehend an extended
thing.
“ If any one say, he knows not what ’tis
thinks in him; he means he knows not what
the substance is of that thinking thing: No more,
say I, knows he what the substance is of that
solid thing. Farther, if he says, he knows not
how he thinks ; I answer, Neither knows he how
he is extended; how the solid parts of body are
united, or cohere together to make extension.”
—(Yol. II. p. 22.)
“ I think we have as many and as clear ideas
belonging to mind, as we have belonging to body,
the substance of each being equally unknown to
us ; and the idea of thinking in mind as clear as
of extension in body; and the communication of
motion by thought which we attribute to mind,
is as evident as that by impulse, which we
ascribe to body. Constant experience makes us
sensible of both of these, though our narrow un¬
derstanding can comprehend neither.1
“To conclude; Sensation convinces us, that
there are solid extended substances; and Re¬
flection, that there are thinking ones : Expe¬
rience assures us of the existence of such beings;
and that the one hath a power to move body by
impulse, the other by thought; this we cannot
doubt of. But beyond these ideas, as received
from their proper sources, our faculties will not
reach. If we would inquire farther into their
nature, causes, and manner, we perceive not the
nature of Extension clearer than we do of Think¬
ing. If we would explain them any farther, one
is as easy as the other; and there is no more
difficulty to conceive how a substance we know
not should by thought set body into motion, than
how a substance we know not should, by im¬
pulse, set body into motion.”—[Ibid. pp. 26. 27.)
The passage in Locke which, on a superficial
view, appears the most favourable to the misin¬
terpretation put on his account of the Sources of
our Knowledge, by so many of his professed
followers, is, in my opinion, the following :
“ It may also lead us a little towards the ori¬
ginal of all our notions and knowledge, if we re¬
mark, how great a dependence our words have
on common sensible ideas; and how those which
are made use of to stand for actions and notions
quite removed from sense, have their rise from
thence, and from obvious sensible ideas are
transferred to more abstruse significations, and
made to stand for ideas that come not under the
cognizance of our senses ; v. g. to imagine, appre¬
hend, comprehend, adhere, conceive, instil, disgust.
ternal or to the internal world. It is in this sense he uses it when he refers to Reflection our ideas of Cause and Effect,
of Identity and Diversity, and of all other relations. “ All of these (he observes) terminate in, and are concerned about, those
simple ideas, either of Sensation or Reflection, which I think to be the whole materials of all our knowledge.”—(Book II.
c. xxv. sect. 9.) From this explanation it would appear that Locke conceived it sufficient to justify his account of the ori¬
gin of our knowledge, if it could be shown that all our ideas terminate in, and are concerned about, ideas derived either from
Sensation or Reflection, according to which comment it will not be a difficult task to obviate every objection to which his
fundamental principle concerning the two sources of our ideas may appear to be liable. _ .
In this lax interpretation of a principle so completely interwoven with the whole of his philosophy, there is undoubtedly
a departure from logical accuracy ; and the same remark may be extended to the vague and indefinite use which he occasion¬
ally makes of the word Reflection; a word which expresses the peculiar and characteristical doctrine, by which his system is
distinguished from that of the Gassendists and Hobbists. All this, however, serves only to prove still more clearly, how
widely remote his real opinion on this subject was from that commonly ascribed to him by the f rench ami German com¬
mentators. For my own part, I do not think, notwithstanding some casual expressions which may seem to favour the con¬
trary supposition, that Locke would have hesitated for a moment to admit, with Cud worth and Price, that the Understand¬
ing is itself a source of new ideas. That it is by Reflection (which, according to his own definition, means merely the exercise
of the Understanding on the internal phenomena) that we get our ideas of memory, imagination, reasoning, and of all other
intellectual powers, Mr Locke has again and again told us; and from this principle it is so obvious an inference, that all the
simple ideas which are necessarily implied in our intellectual operations, are ultimately to be referred to the same source,
that we cannot reasonably suppose a philosopher of Locke’s sagacity to admit the former proposition, and to withhold his
assent to the latter. . .
1 In transcribing this paragraph, I have taken the liberty to substitute the word Mind instead of Spirit. 1 he two words
were plainly considered by Locke, on the present occasion, as quite synonymous; and the latter (which seems to involve a
theory concerning the nature of the thinking principle) is now almost universally rejected by English metaphysicians
from their Philosophical Vocabulary.
DISSERTATION FIRST.
113
disturbance, tranquillity, &c. are all words taken
from the operations of sensible things, and ap¬
plied to certain inodes of thinking. Spirit, in
its primary signification, is breath; angel, a mes¬
senger : and I doubt not, but if we could trace them
to their sources, we should find, in all languages,
the names which stand for things that fall not under
our senses, to have had their first rise from sensible
ideas. By which we may give some kind of
guess what kind of notions they were, and
whence derived, which filled their minds, who
were the first beginners of languages; and how
nature, even in the naming of things, unawares
suggested to men the originals and principles of
all their knowledge.”
So far the words of Locke coincide very near-
y, if not exactly, with the doctrines of Hobbes
and of Gassendi; and I have not a doubt, that
a mistaken interpretation of the clause which I
have distinguished by italics, furnished the germ
of all the mighty discoveries contained in the
E-rsa Ungosvra,. If Mr Tooke, however, had studied
with due attention the import of what immediate¬
ly follows, he must have instantly perceived how
essentially different Locke’s real opinion on the
subject was from what he conceived it to he.—
“ Whilst to give names, that might make known
to others any operations they felt in themselves,
or any other ideas that came not under their
senses, they were fain to borrow words from
ordinary known ideas of sensation, by that means
to make others the more easily to conceive those
operations they experienced in themselves, which
made no outward sensible appearances; and
then, when they had got known and agreed
names, to signify those internal operations of
their own minds, they were sufficiently furnish¬
ed to make known by words all their other ideas;
since they could consist of nothing but either of
outward sensible perceptions, or of the inward
operations of their minds about them.”—(Vol.
II. pp. 147, 148.)
From the sentences last quoted it is manifest,
that when Locke remarked the material etymo¬
logy of all our language about mind, he had not
the most distant intention to draw from it any
inference which might tend to identify the
sensible images which this language presents to
the fancy, with the metaphysical notions which
DISS. I. PART II.
it figuratively expresses. Through the whole of
his Essay, he uniformly represents sensation and
reflection as radically distinct sources of know¬
ledge ; and, of consequence, he must have con¬
ceived it to be not less unphilosophical to attempt
an explanation of the phenomena of mind by
the analogy of matter, than to think of explain¬
ing the phenomena of matter by the analogy of
mind. To this fundamental principle concern¬
ing the origin of our ideas, he has added, in the
passage now before us, That, as our knowledge
of mind is posterior in the order of time to that
of matter (the first years of our existence being
necessarily occupied about objects of sense), it
is not surprising, that “ when men wished to
give names that might make known to others any
operations they felt in themselves, or any other
ideas that came not under their senses, they
should have been fain to borrow words from
ordinary known ideas of sensation, by that means
to make others the more easily to conceive those
operations which make no outward sensible ap¬
pearances.” According to this statement, the
purpose of these “borrowed” or metaphorical
words is not (as Mr Tooke concluded) to explain
the nature of the operations, but to direct the
attention of the hearer to that internal world,
the phenomena of which he can only learn to
comprehend by the exercise of his own power
of reflection. If Locke has nowhere affirmed
so explicitly as his predecessor Descartes, that
“ nothing conceivable by the power of imagina¬
tion can throw any light on the operations of
thought,” it may be presumed that he consider¬
ed this as unnecessary, after having dwelt so
much on reflection as the exclusive source of all
our ideas relating to mind; and on the peculiar
difficulties attending the exercise of this power,
in consequence of the effect of early associations
in confounding together our notions of mind and
of matter.
The misapprehensions so prevalent on the
Continent, with respect to Locke’s doctrine on
this most important of all metaphysical questions,
began during his own life time, and were coun¬
tenanced by the authority of no less a writer than
Leibnitz, who always represents Locke as a par-
tizan of the scholastic maxim, Nihil est in intel-
lectu quod non fuerit in sensu.—“ Nempe (says
114
PRELIMINARY DISSERTATIONS.
Leibnitz, in reply to this maxim) nihil est in in-
tellectu quod non fuerit in sensu, nisi ipse intel-
lectus”1 The remark is excellent, and does
honour to the acuteness of the critic; but it is
not easy to conceive on what grounds it should
have been urged as an objection to a writer, who
1 Opera, Tom. V. pp. 358, 359.
That the same mistake still keeps its ground among many foreign writers of the highest class, the following passage affords
a sufficient proof: “ Leibnitz a combattu avec une force de dialectique admirable le Systeme de Locke, qui attribue toutes
nos idees a nos sensations. On avoit mis en avant cet axiome si connu, qu’il n’y avoit rien dans I’intelligence qui n’eut dtd
d’abord dans les sensations, et Leibnitz y ajouta cette sublime restriction, si ce n'est Vintelligence elle-meme. De ce principe
derive toute la philosophie nouvelle qui exerce tant d’influence sur les esprits en Allemagne.”—(Mad. de Stael de VAlle-
magne, Tom. III. p. 65.)
I observed in the First Part of this Dissertation (page 67), that this sublime restriction on which so much stress has been
laid by the partizans of the German school, is little more than a translation of the following words of Aristotle: Kal abroi
vovs vonro; iffnv, cStrvritJ ra. votira." it/ /u.lv ya/) rwv uvtii vXris, to avrb Itt/ to vaovv xa) to voou^msvov.—(De Anima, Lib. III. cap. V.)
As to Locke, the same injustice which he received from Leibnitz was very early done to him in his own country. In a
tract printed in 1697, by a mathematician of some note, the author of the Essay on Human Understanding is represented as
holding the same opinion with Gassendi concerning the origin of our ideas. “ Ideas nomine sensu utor; earum originem an
a sensibus solum, ut Gassendo et Lockio nostrati, cseterisque plurimis visum est, an aliunde, hujus loci non est inquirere.”—
(Z)e Spatio Reali, sen Ente Infinito Conamen Mathematico-Metaphysicum. Auctore Josepho Haphson, Reg. Soc. Socio. This
tract is annexed to the second edition of a work entitled Analysis JEquationum Universalis. Lond. 1702.)
In order to enable my readers more easily to form a judgment on the argument in the text, I must beg leave once more
to remind them of the distinction already pointed out between the Gassendists and the Cartesians; the former asserting,
that, as all our ideas are derived from the external senses, the intellectual phenomena can admit of no other explanation
than what is furnished by analogies drawn from the material world; the latter rejecting these analogies altogether, as de¬
lusive and treacherous lights in the study of mind; and contending, that the exercise of the power of reflection is the only
medium through which any knowledge of its operations is to be obtained. To the one or the other of these two classes, all
the metaphysicians of the last century may be referred; and even at the present day, the fundamental question which
formed the chief ground of controversy between Gassendi and Descartes (I mean the question concerning the proper logical
method of studying the mind) still continues the hinge on which the most important disputes relating to the internal world
will be found ultimately to turn.
According to this distinction, Locke, notwithstanding some occasional slips of his pen, belongs indisputably to the class
of Cartesians; as well as the very small number of his followers who have entered thoroughly into the spirit of his philo¬
sophy. To the class of Gassendists, on the other hand, belong all those French metaphysicians, who professing to tread
in Locke’s footsteps, have derived all their knowledge of the Essay on Human Understanding from the works of Condillac;
together with most of the commentators on Locke who have proceeded from the school of Bishop Law. To these may be
added (among the writers of later times) Priestley, Darwin, Beddoes, and, above all, Horne Tooke with his numerous
disciples.
The doctrine of Hobbes on this cardinal question coincided entirely with that of Gassendi, and, accordingly, it is not
unusual in the present times, among Hobbes’s disciples, to ascribe to him the whole merit of that account of the origin of
our knowledge, which, from a strange misconception, has been supposed to have been claimed by Locke as his own dis¬
covery. But where, it may be asked, has Hobbes said anything about the origin of those ideas which Locke refers to the
power of reflection ? and may not the numerous observations which Locke has made on this power as a source of ideas peculiar
to itself, be regarded as an indirect refutation of that theory which would resolve all the objects of our knowledge into
sensations, as their ultimate elements ? This was not merely a step beyond Hobbes; but the correction of an error which lies
at the very root of Hobbes’s system ;—an error under which (it may be added) the greater part of Hobbes’s eulogists
have the misfortune still to labour.
It is with much regret I add, that a very large proportion of the English writers, who call themselves LocJdsts, and
who, I have no doubt, believe themselves to be so in reality, are at bottom (at least in their metaphysical opinions)
Gassendists or Hobbists. In what respect do the following observations differ from the Epicurean theory concerning the
origin of our knowledge, as expounded by Gassendi ? “ The ideas conveyed by sight, and by our other senses, having
entered the mind, intermingle, unite, separate, throw themselves into various combinations and postures, and thereby
generate new ideas of reflection, strictly so called; such as those of comparing, dividing, distinguishing,—of abstraction,
relation, with many others; all which remain with us as stock for our further use on future occasions.” I do not recollect
any passage, either in Helvetius or Diderot, which contains a more explicit and decided avowal of that Epicurean system
of Metaphysics, which it was the great aim both of Descartes and of Locke to overthrow.
In the following conjectures concerning the nature of our ideas, the same author has far exceeded in extravagance any of
the Metaphysicians of the French school. “ What those substances are, whereof our ideas are the modifications, •whether parts
of the mind as the members are of our body, or contained in it like wafers in a box, or enveloped by it likefish in water, whether of a spiri¬
tual, corporeal, or middle nature between both, 1 need not now ascertain. All I mean to lay down at present is this, that,
in every exercise of the understanding, that which discerns is numerically and substantially distinct from that which is dis¬
cerned ; and that an act of the understanding is not so much our own proper act, as the act of something else operating
upon us.”
I should scarcely have thought it worth while to take notice of these passages, had not the doctrines contained in the
work from which they are taken, been sanctioned in the most unqualified terms by the high authority of Dr Paley. “There
is one work (he observes) to which I owe so much, that it would be ungrateful not to confess the obligation : I mean the
writings of the late Abraham Tucker, Esq. part of which were published by himself, and the remainder since his death,
under the title of the Light of Nature Pursued, by Edward Search, Esq.” “ / have found, in this writer, more original thinking
and observation upon the several subjects that he has taken in hand, than in any other, not to say than in all others put together. His talent
also for illustration is unrivalled. But his thoughts are diffused through a long, various, and irregular work. I shall account
DISSERTATION FIRST.
115
has insisted so explicitly and so frequently onre-
flection as the source of a class of ideas essential¬
ly different from those which are derived from
sensation. To myself it appears, that the words
of Leibnitz only convey, in a more concise and
epigrammatic form, the substance of Locke’s
doctrine. Is any thing implied in them which
Locke has not more fully and clearly stated in
the following sentence ? cc External objects
furnish the mind with the ideas of sensible
qualities; and the mind furnishes the under¬
standing with ideas of its own operations.”
(Locke’s Works, Yol. I. p. 79.)
The extraordinary zeal displayed by Locke,
at the very outset of his work, against the hy¬
pothesis of innate ideas, goes far to account for
the mistakes committed by his commentators, in
interpreting his account of the origin of our
knowledge. It ought, however, to be always
kept in view, in reading his argument on the
subject, that it is the Cartesian theory of innate
ideas which he is here combating; according to
which theory (as understood by Locke), an in¬
nate idea signifies something coeval in its existence
with the mind to which it belongs, and illuminat¬
ing the understanding before the external senses
begin to operate. The very close affinity be¬
tween this theory, and some of the doctrines of
the Platonic school, prevented Leibnitz, it is
probable, from judging of Locke’s argument
against it, with his usual candour ; and disposed
him hastily to conclude, that the opposition of
Locke to Descartes proceeded from views essen¬
tially the same with those of Gassendi, and of
his other Epicurean antagonists. How very
widely he was mistaken in this conclusion, the
numerous passages which I have quoted in
Locke’s own words sufficiently demonstrate.
In what respects Locke’s account of the origin
of our ideas falls short of the truth, will appear,
when the metaphysical discussions of later times
come under our review. Enough has been al¬
ready said to show, how completely this account
has been misapprehended, not only by his oppo¬
nents, but by the most devoted of his admirers ;—
a misapprehension so very general, and at the
same time so obviously at variance with the
whole spirit of his Essay, as to prove to a de¬
monstration that, in point of numbers, the in¬
telligent readers of this celebrated work have
hitherto borne but a small proportion to its
purchasers and panegyrists. What an illustra¬
tion of the folly of trusting, in matters of lite¬
rary history, to the traditionary judgments copied
by one commentator or critic from another, when
recourse may so easily be had to the original
sources of information I1
II. Another misapprehension, not less pre¬
valent than the former, with respect to Locke’s
philosophical creed, relates to the power of mo¬
ral perception, and the immutability of moral
distinctions. The consideration of such ques-
1 In justice to Dr Hartley, I must here observe, that, although his account of the origin of our ideas is precisely the
same with that of Gassendi, Hobbes, and Condillac—one of his fundamental principles being, that the ideas of sensation are
the elements of which all the rest are compounded—(Hartley on Man, 4th Ed. p. 2. of the Introduction)—he has not availed
himself, like the other Gassendists of later times, of the name of Locke to recommend this theory to the favour of his
readers. On the contrary, he has very clearly and candidly pointed out the wide and essential distinction between the
two opinions. “ It may not be amiss here to take notice how far the theory of these papers has led me to differ, in respect
of logic, from Mr Locke’s excellent Essay on the Human Understanding, to which the world is so much indebted for re¬
moving prejudices and encumbrances, and advancing real and useful knowledge.
“ First, then, it appears to me, that all the most complex ideas arise from sensation, and that reflection is not a distinct
source, as Mr Locke makes it.”—(Hartley on Man, 4th Ed. p. 360 of the Introduction.)
This last proposition Hartley seems to have considered as an important and original improvement of his own on Locke’s
it no mean praise, if I have been sometimes able to dispose into method, to collect into heads and articles, or to exhibit in
more compact and tangible masses, what, in that excellent performance, is spread over too much surface.”—(Principles of
Moral and Political Philosophy, Preface, pp. 25, 26.)
Of an author whom Dr Paley has honoured with so very warm an eulogy, it would be equally absurd and presumptuous
to dispute the merits. Nor have I any wish to detract from the praise here bestowed on him as an original thinker and ob¬
server. I readily admit, also, his talent for illustration, although it sometimes leads him to soar into bombast, and more
frequently to sink into buffoonery. As an honest inquirer after moral and religious truth, he is entitled to the most un¬
qualified approbation. But, I must be permitted to add, that, as a metaphysician, he seems to me much more fanciful than
solid ; and, at the same time, to be so rambling, verbose, and excursive, as to be more likely to unsettle than to fix the
principles of his readers.
116
PRELIMINARY DISSERTATIONS.
tions, it may at first sight be thought, belongs
rather to the history of Ethics than of Meta¬
physics ; hut it must he recollected, that, in in¬
troducing them here, I follow the example of
Locke himself, who has enlarged upon them at
considerable length, in his Argument against
the Theory of Innate Ideas. An Ethical disqui¬
sition of this sort formed, it must he owned, an
aukward introduction to a work on the Human
Understanding; hut the conclusion on which it
is meant to bear is purely of a Metaphysical
nature; and when combined with the premises
from which it is deduced, affords a good illus¬
tration of the impossibility, in tracing the pro¬
gress of these two sciences, of separating com¬
pletely the history of the one from that of the
other.
In what sense Locke’s reasonings against In¬
nate Ideas have been commonly understood, may
he collected from the following passage of an
author, who had certainly no wish to do injus¬
tice to Locke’s opinions.
logic ; whereas, in fact, it is only a relapse into the old Epicurean hypothesis, which it was one of the main objects of Locke’s
Essay to explode.
I would not have enlarged so fully on Locke’s account of the origin of our ideas, had not a mistaken view of his argument
on this head, served as a ground-work for the whole Metaphysical Philosophy of the French Encyclopedic. That all our
knowledge is derived from our external senses, is everywhere assumed by the conductors of that work as a demonstrated
principle ; and the credit of this demonstration is uniformly ascribed to Locke, who, we are told, was the first that fully un¬
folded and established a truth, of which his predecessors had only an imperfect glimpse. La Harpe, in his Lycee, has, on
this account, justly censured the metaphysical phraseology of the Encyclopedic, as tending to degrade the intellectual nature
of man ; while, with a strange inconsistency, he bestows the most unqualified praise on the writings of Condillac. Little
did he suspect, when he wrote the following sentences, how much the reasonings of his favourite logician had contributed to
pave the way for those conclusions which he reprobates with so much asperity in Diderot and D’Alembert.
“ La gloire de Condillac est d’avoir dte le premier disciple de Locke ; mais si Condillac eut un maitre, il merita d’en ser-
vir a tous les autres ; il repandit meme une plus grande lumiere sur les decouvertes du philosophe Anglois; il les rendit
pour ainsi dire sensibles, et c’est grace a lui qu’elles sent devenues communes et familieres. En un mot, la saine Me'ta-
physique ne date en France, que des ouvrages de Condillac, et a ce titre il doit etre comptd dans le petit nombre d’hommes
qui ont avance la science qu’ils ont cultivee.”—(Lyric, Tome XY. pp. 136. 137.
La Harpe proceeds in the same panegyrical strain through more than seventy pages, and concludes his eulogy of Con¬
dillac with these words : “ Le style de Condillac est clair et pur comme ses conceptions; c’est en general 1’esprit le plus
juste et le plus lumineux qui ait contribue, dans ce siecle, aux progres de la bonne philosophic.”.—(Ibid. p. 214.)
La Harpe’s account of the power of Refiection wrill form an appropriate supplement to his comments on Condillac. “ L’im-
pression sentie des objets se nomme perception; Paction de 1’ame qui les considere, se nomme reflexion. Ce mot, il est vrai,
exprime un mouvement physique, celui de se replier sur soi-meme ou sur quelque chose ; mais Unites nos idees venant des sens,
nous sommes souvent obliges de nous servir de termes physiques pour exprimer les operations de Pame.”—(Ibid. p. 158.)
In another passage, he defines Reflection as follows : “ La facultd de reflexion, e’est-a-dire, le pouvoir qu’a notre ame, de
comparer, d’assembler, de combiner les perceptions.”—(Ibid. p. 183.) How widely do these definitions of reflection differ
from that given by Locke; and how exactly do they accord with the Philosophy of Gassendi, of Hobbes, and of Diderot!
In a lately published sketch Of the State of French Literature during the Eighteenth Century (a work, to which the Author’s
taste and powers as a writer have attracted a degree of public attention something beyond what was due to his philosophi¬
cal depth and discernment), there are some shrewd, and, in my opinion, sound remarks, on the moral tendency of that me¬
taphysical system to which Condillac gave so much circulation and celebrity. I shall quote some of his strictures which
bear more particularly on the foregoing argument.
“ Autrefois, negligeant d’exatniner tout ce mecanisme des sens, tous ces rapports directs du corps avec les objets, les phi-
losophes ne s’occupoient que de ce qui se passe au-dedans de 1’homme. La science de Fame, telle a ete la noble dtude de
Descartes, de Pascal, de Malebranche, de Leibnitz. (Why omit in this list the name of Locke ?) Peut-etre se per-
doient-ils quelquefois dans les nuages des hautes regions oil ils avoient pris leur vol; peut-etre leurs travaux etoient-ils
sans application directe ; mais du moins ils suivoient une direction elevee, leur doctrine etoit en rapport avec les pensees
qui nous agitent quand nous reflechissbns profondement sur nous-memes. Cette route conduisoit ndeessairement au plus
nobles des sciences, a la religion, et a la morale. Elle supposoit dans ceux qui la cultivoient un gdnie dlevd et de vastes
meditations.
“ On se lassa de les suivre; on traita de vaines subtilites, on fletrit du titre de reveries scholastiques les travaux de ces
grandes esprits. On se jeta dans la science des sensations, esperant qu’elle seroit plus a la portee de 1’intelligence humaine.
On s’occupa de plus en plus des rapports mecaniques de 1’homme avec les objets, et de I’influence de son organisation phy¬
sique. De eette sorte, la mdtaphysique alia toujours se rabaissant, au point que maintenant, pour quelques personnes, elle
se confond presque avec la physiologie. . . . Le dix-huitieme siecle a voulu faire de cette maniere d’envisager 1’homme un de
ses principaux litres de gloire 
“ Condillac est le chef de cette ecole. C’est dans ses ouvrages que cette metaphysique exerce toutes les seductions de la
methode, et de la lucidite; d’autant plus claire, qu’elle est moins profonde. Peu d’ecrivains ont obtenu plus de succes. Il
reduisit k la portee du yulgaire la science de la pensde, en retranchant tout ce qu’elle avoit d’e'leve. Chacun fut surpris et
glorieux de pouvoir philosophey si facilement; et 1’on eut une grande reconnoissance pour celui a qui 1’on devoit ce bienfait.
On ne s’apperqut pas qu’il avoit rabaisse la science, au lieu de rendre ses disciples capable d’y atteindre.”—(Tableau de la
Litterature Franchise pendant le dix-huitieme Siecle, pp. 87. 88. 89. 92.)
DISSERTATION FIRST.
117
“ The First Book (says Dr Beattie) of the
Essay on Human Understanding, which, with sub¬
mission, I think the worst, tends to establish
this dangerous doctrine, that the human mind,
previous to education and habit, is as suscep¬
tible of any one impression as of any other:—a
doctrine which, if true, would go near to prove,
that truth and virtue are no better than human
contrivances ; or at least, that they have nothing
permanent in their nature, but may be as
changeable as the inclinations and capacities of
men.” Dr Beattie, however, candidly and judi¬
ciously adds, C{ Surely this is not the doctrine
that Locke meant to establish; but his zeal
against innate ideas, and innate principles, put
him off his guard, and made him allow too little
to instinct, for fear of allowing too much.”
In this last remark, I perfectly agree with Dr
Beattie; although I am well aware, that a con¬
siderable number of Locke’s English disciples
have not only chosen to interpret the first book
of his Essay in that very sense in which it ap¬
peared to Dr Beattie to be of so mischievous a
tendency, but have avowed Locke’s doctrine,
when thus interpreted, as their own ethical creed.
In this number, I am sorry to say, the respec¬
table name of Paley must be included.1
It is fortunate for Locke’s reputation, that, in
other parts of his Essay, he has disavowed, in
the most unequivocal terms, those dangerous
conclusions which, it must be owned, the gene¬
ral strain of his first book has too much the ap¬
pearance of favouring. “ He that hath the idea
(he observes on one occasion) of an intelligent,
but frail and weak being, made by and depend¬
ing on another, who is omnipotent, perfectly
wise, and good, will as certainly know, that man
is to honour, fear, and obey God, as that the sun
shines when he sees it; nor can he be surer, in
a clear morning, that the sun is risen, if he will
but open his eyes, and turn them that way.
But yet these truths being never so certain, never
so clear, he may be ignorant of either, or all of
them, who will never take the pains to employ
his faculties as he should to inform himself about
them.” To the same purpose, he has elsewhere
said, that “ there is a Law of Nature, as intel¬
ligible to a rational creature and studier of that
law, as the positive laws of commonwealths.”
Nay, he has himself, in the most explicit terms,
anticipated and disclaimed those dangerous con¬
sequences which, it has been so often supposed,
it was the chief scope of this introductory chap¬
ter to establish. ii I would not be mistaken,
as if, because I deny an innate law, I thought
there were none but positive laws. There is a
great deal of difference between an innate law
and a law of nature; between something im¬
printed on our minds in their very original, and
something that we, being ignorant of, may at¬
tain to the knowledge of, by the use and due
application of our natural faculties. And I
think they equally forsake the truth, who, run-,
ning into the contrary extremes, either affirm
an innate law, or deny that there is a law know-
able by the light of nature, without the help of
a positive revelation.” (Vol. I. p. 44.) Nor
was Locke unaware of the influence on men’s
lives of their speculative tenets concerning these
metaphysical and etliical questions. On this
point, which can alone render such discussions
interesting to human happiness, he has express¬
ed himself thus: “ Let that principle of some
of the philosophers, that all is matter, and that
there is nothing else, be received for certain and
indubitable, and it will be easy to be seen, by
the writings of some that have revived it again
in our days, what consequences it will lead in¬
to....Nothing can be so dangerous as principles
thus taken up without due questioning or exami¬
nation ; especially if they be such as influence
men’s lives, and give a bias to all their actions.
He that with Archelaus shall lay it down as a
principle, that right and wrong, honest and dis¬
honest, are defined only by laws, and not by
nature, will have other measures of moral recti¬
tude and pravity, than those who take it for
granted, that we are under obligations antece¬
dent to all human constitutions.”—(Yol. III. p.
75.) Is not the whole of this passage evidently
1 See Principles of Moral and Political Philosophy, Book I. Chap. 5, where the author discusses the question concerning
A moral sente.
*
118
PRELIMINARY DISSERTATIONS.
pointed at the Epicurean maxims of Hobbes and
of Gassendi?1
Lord Shaftesbury was one of the first who
sounded the alarm against what he conceived to
be the drift of that philosophy which denies the
existence of innate principles. Various strictures
on this subject occur in the Characteristics ; par¬
ticularly in the treatise entitled Advice to an Au¬
thor ; but the most direct of all his attacks upon
Locke is to be found in his 8th Letter, address¬
ed to a Student at the University. In this let¬
ter he observes, that “ all those called free wri¬
ters now-a-days have espoused those principles
which Mr Hobbes set a foot in this last age.”—
“ Mr Locke (he continues), as much as I ho¬
nour him on account of other writings (on Go¬
vernment, Policy, Trade, Coin, Education, To¬
leration, &c.) and as well as I knew him, and
can answer for his sincerity as a most zealous
Christian and believer, did however go in the
self-same tract; and is followed by the Tindals,
and all the other free authors of our times !
“ ’Twas Mr Locke that struck the home blow:
for Mr Hobbes’s character, and base slavish
principles of government, took off the poison of
his philosophy. ’Twas Mr Locke that struck
at all fundamentals, threw all order and virtue
out of the world, and made the very ideas of
these (which are the same with those of God)
unnatural, and without foundation in our minds.
Innate is a word he poorly plays upon : the right
word, though less used, is connatural. For what
has birth or progress of the foetus out of the
womb to do in this case ?—the question is not
about the time the ideas entered, or the moment
that one body came out of the other; but whe¬
ther the constitution of man be such, that, being
adult and grown up, “ at such a time, sooner or
later (no matter when,) the idea and sense of
order, administration, and a God, will not infal¬
libly, inevitably, necessarily spring up in him.”
In this last remark Shaftesbury appears to me
to place the question about innate ideas upon the
right and only philosophical footing; and to af¬
ford a key to all the confusion running through
Locke’s argument against their existence. The
sequel of the above quotation is not less just and
valuable—but I must not indulge myself in any
farther extracts. It is sufficient to mention the
perfect coincidence between the opinion of
Shaftesbury, as here stated by himself, and that
formerly quoted in the words of Locke; and, of
consequence, the injustice of concluding, from
some unguarded expressions of the latter, that
there was, at bottom, any essential difference
between their real sentiments.5
Under the title of Locke’s Metaphysical (or,
to speak with more strict precision, his Logical)
writings, may also be classed his tracts on Edu¬
cation, and on the Conduct of the Understand-
1 To the above quotations from Locke, the following deserves to be added: “ Whilst the parties of men cram their
tenets down all men’s throats, whom they can get into their power, without permitting them to examine their truth or
falsehood, and will not let truth have fair play in the world, nor men the liberty to search after it; what improvements
can be expected of this kind ? What greater light can be hoped for in the moral sciences ? The subject part of mankind
in most places might, instead thereof, with Egyptian bondage expect Egyptian darkness, ■were not the candle of the Lord set
np by himself in men's minds, which it is impossible for the breath or power of man wholly to extinguish."—Vol. II. pp. 343,
344.
* Lord Shaftesbury should have said, “ grown up to the possession and exercise of his reasoning powers.”
3 I must, at the same time, again repeat, that the facts and reasonings contained in the introduction to Locke’s Essay
go very far to account for the severity of Shaftesbury’s censures on this part of his work. Sir Isaac Newton himself, an in¬
timate friend of Locke’s, appears, from a letter of his which I have read in his own handwriting, to have felt precisely in
the same manner with the author of the Characteristics. Such, at least, were his first impressions ; although he afterwards
requested, with a humility and candour worthy of himself, the forgiveness of Locke, for this injustice done to his character.
“ I beg your pardon (says he) for representing that you struck at the root of morality in a principle you laid down in your
book of ideas, and designed to pursue in another book ; and that I took you for a Hobbist.” In the same letter Newton
alludes to certain unfounded suspicions which he had been led to entertain of the propriety of Locke’s conduct in some of
their private concerns; adding, with an ingenuous and almost infantine simplicity, ‘ I was so much affected with this, that
when one told me you was sickly and would not live> I answered, ’twere better if you were dead. I desire you to forgive
me this uncharitableness.” The letter is subscribed, your most humble and most unfortunate servant. Is. Newton.*
The rough draft of Mr Locke’s reply to these afflicting acknowledgments was kindly communicated to me by a friend
some years ago. It is written with the magnanimity of a philosopher, and with the good-humoured forbearance of a man
of the world; and it breathes throughout so tender and so unaffected a veneration for the good as well as great qualities of
the excellent person to whom it is addressed, as demonstrates at once the conscious integrity of the writer, and the supe¬
riority of his mind to the irritation of little passions. I know of nothing from Locke’s pen which does more honour to his
* It is dated at the Bull in Shoreditch, London, September 1093 ; and is addressed, For John Locke, Esq. at Sir Fra. Masham't,
Bart, at Oates, in Essex.
DISSERTATION FIRST.
119
ing. These tracts are entirely of a practical
nature, and were plainly intended for a wider
circle of readers than his Essay ; hut they every¬
where bear the strongest marks of the same zeal
for extending the empire of Truth and of Reason,
and may he justly regarded as parts of the same
great design.1 It has been often remarked, that
they display less originality than might have
been expected from so bold and powerful a think¬
er; and, accordingly, both of them have long
fallen into very general neglect. It ought, how¬
ever, to be remembered, that, on the most im¬
portant points discussed in them, new suggestions
are not now to be looked for; and that the great
object of the reader should be, not to learn some¬
thing which he never heard of before, but to
learn, among the multiplicity of discordant pre¬
cepts current in the world, which of them were
sanctioned, and which reprobatedby the judgment
of Locke. The candid and unreserved thoughts
of such a writer upon such subjects as Education,
and the culture of the intellectual powers, possess
an intrinsic value, which is not diminished by
the consideration of their triteness. They not
only serve to illustrate the peculiarities of the
author’s own character and views, but, con¬
sidered in a practical light, come recommended
to us by all the additional weight of his dis¬
criminating experience. In this point of view,
the two tracts in question, but more especially
that on the Conduct of the Understanding, will
always continue to be interesting manuals to
such as are qualified to appreciate the mind from
which they proceeded.*
It must not, however, be concluded from the
apparent triteness of some of Locke’s remarks, to
the present generation of readers, that they were
viewed in the same light by his own contempo-
temper and character; and I introduce it with peculiar satisfaction, in connection with those strictures which truth has ex¬
torted from me on that part of his system which to the moralist stands most in need of explanation and apology.
MR LOCKE TO MR NEWTON.
“ Sir, Oates, 5th October 93.
“ I have been ever since I first knew you so kindly and sincerely your friend, and thought you so much
mine, that I could not have believed what you tell me of yourself, had I had it from any body else. And though I cannot
but be mightily troubled that you should have had so many wrong and unjust thoughts of me, yet, next to the return of
good offices, such as from a sincere good will I have ever done you, I receive your acknowledgment of the contrary as the
kindest thing you could have done me, since it gives me hopes I have not lost a friend I so much valued. After what your
letter expresses, I shall not need to say anything to justify myself to you : I shall always think your own reflection on my
carriage both to you and all mankind will sufficiently do that. Instead of that, give me leave to assure you, that I am more
ready to forgive you than you can be to desire it; and I do it so freely and fully that I wish for nothing more than the op¬
portunity to convince you that I truly love and esteem you; and that I have still the same good will for you as if nothing
of this had happened. To confirm this to you more fully, I should be glad to meet you anywhere, and the rather, because the
conclusion of your letter makes me apprehend it would not be wholly useless to you. I shall always be ready to serve you
to my utmost, in any way you shall like, and shall only need your commands or permission to do it.
“ My book is going to press for a second edition; and, though I can answer for the design with which I writ it, yet,
since you have so opportunely given me notice of what you have said of it, I should take it as a favour if you would point
out to me ttye places that gave occasion to that censure, that, by explaining myself better, I may avoid being mistaken by
others, or unwillingly doing the least prejudice to truth or virtue. I am sure you are so much a friend to both, that, were
you none to me, I could expect this from you. But I cannot doubt but you would do a great deal more than this for my
sake, who, after all, have all the concern of a friend for you, wish you extremely well, and am, without compliment,” &c. &c.
(For the preservation of this precious memorial of Mr Locke, the public is indebted to the descendants of his friend and
relation the Lord Chancellor King, to whom his papers and library were bequeathed. The original is still in the posses¬
sion of the present representative of that noble family ; for whose flattering permission to enrich my Dissertation with the
above extracts, I feel the more grateful, as I have not the honour of being personally known to his Lordship.)
1 Mr Locke, it would appear, had once intended to publish his thoughts on the Conduct of the Understanding, as an ad¬
ditional chapter to his Essay. “ I have lately,” says he, in a Letter to Mr Molyneux, “ got a little leisure to think of
some additions to my book against the next edition, and within these few days have fallen upon a subject that I know not
how far it will lead me. I have written several pages on it, but the matter, the farther I go, opens the more upon me,
and I cannot get sight of any end of it. The title of the chapter will be, Of the Conduct of the Understanding, which, if I
shall pursue as far as I imagine it will reach, and as it deserves, will, 1 conclude, make the largest chapter of my Essay.”
(Locke’s JFbrfo, Yol. IX. p. 407.)
2 A similar remark may be extended to a letter from Locke to his friend Mr Samuel Bold, who had complained to him
of the disadvantages he laboured under from a weakness of memory. It contains nothing but what might have come from
the pen of one of Newberry’s authors ; but with what additional interest do we read it, when considered as a comment by
Locke on a suggestion of Bacon’s !—(Locke’s Works, Yol. X. p. 317-)
It is a judicious reflection of Shenstone’s, that “ every single observation published by a man of genius, be it ever so tri¬
vial, should be esteemed of importance, because he speaks from his own impressions ; whereas common men publish common
things, which they have perhaps gleaned from frivolous writers. I know of few authors to whom this observation applies
more forcibly and happily than to Locke, when he touches on the culture of the intellectual powers. His precepts, indeed,
are not all equally sound ; but they, in general, contain a large proportion of truth, and may always furnish to a specula¬
tive mind matter of useful meditation.
120
preliminary dissertations.
raries. On the contrary, Leibnitz speaks of the
Treatise on Education as a work of still greater
merit than the Essay on Human Understanding.1 2 *
Nor will this judgment be wondered at by those
who, abstracting from the habits of thinking in
which they have been reared, transport them¬
selves in imagination to the state of Europe a
hundred years ago. How flat and nugatory
seem now the cautions to parents about watching
over those associations on which the dread of
spirits in the dark is founded ! But how different
was the case (even in Protestant countiies) till
a very recent period of the last century !
I have, on a former occasion, taken notice of
the slow hut (since the invention of printing) cer¬
tain steps by which Truth makes its way in the
world; “ the discoveries, which, in one age, are
confined to the studious and enlightened few, be¬
coming, in the next, the established, creed of the
learned; and, in the third, forming part of the
elementary principles of education.” The har¬
mony, in the meantime, which exists among truths
of all descriptions, tends perpetually, by blending
them into one common mass, to increase the
joint influence of the whole; the contributions
of individuals to this mass (to borrow the fine
allusion of Middleton) 44 resembling the drops of
rain, which, falling separately into the water,
mingle at once with the stream, and strengthen
the general current.” Hence the ambition, so
natural to weak minds, to distinguish themselves
by paradoxical and extravagant opinions; for
these, having no chance to incorporate themselves
with the progressive reason of the species, are
the more likely to immortalise the eccentricity
of their authors, and to furnish subjects of won¬
der to the common compilers of literary history.
This ambition is the more general, as so little
expence of genius is necessary for its gratification.
*4 Truth (as Mr Hume has well observed) is owe
thing, but errors are numberless;” and hence
(he might have added) the difficulty of seizing
the former, and the facility of swelling the num¬
ber of the latter.®
Having said so much in illustration of Locke s
philosophical merits, and in reply to the common
charge against his metaphysical and ethical prin¬
ciples, it now only remains for me to take notice
of one or two defects in his intellectual character,
which exhibit a strong contrast to the general
vigour of his mental powers.
Among these defects, the most prominent is,
the facility with which he listens to historical
evidence, when it happens to favour his own con¬
clusions. Many remarkable instances of this
occur in his long and rambling argument (some¬
what in the style of Montaigne) against the ex¬
istence of innate practical principles; to which
may be added, the degree of credit he appears
to have given to the popular tales about mer¬
maids, and to Sir William Temple’s idle story
of Prince Maurice’s 44 rational and intelligent
parrot.” Strange ! that the same person who,
in matters of reasoning, had divested himself,
almost to a fault, of all reverence for the opinions
of others, should have failed to perceive, that, of
all the various sources of error, one of the most
copious and fatal is an unreflecting faith in hu¬
man testimony !
The disrespect of Locke for the wisdom of
antiquity, is another prejudice which has fre¬
quently given a wrong bias to Ids judgment.
The idolatry in which the Greek and Roman
writers were held by his immediate predecessors,
although it may help to account for this weak¬
ness, cannot altogether excuse it in a man of so
strong and enlarged an understanding. Locke
(as we are told by Dr Warton) 44 affected to de¬
preciate the ancients; which circumstance (he
adds), as I am informed from undoubted autho¬
rity, was the source of perpetual discontent and
dispute betwixt him and his pupil, Lord Shaftes-
1 Leib. Op. Tom. VI. p. 226. , , .. ,
2 Descartes has struck into nearly the same train of thinking with the above, but his remarks apply much be ter o
writings of Locke than to his own. * a-(P' i a l
“ L’experience m’apprit, que quoique mes opinions surprennent d’abord, parce qu’elles sont tort uitlerentesyies \u -
eaires, cependant, apres qu’on les a comprises on les trouve si simples et si conformes au sens cornmun, qu on cesse
entierement de les admirer, et par la meme d’en faire cas: parceque tel est le naturel des. hommes qu ns n estimen
que les choses qui leur laissent d’admiration et qu’ils ne possedent pas tout-a-fait. C’est ainsi que quoique la sante sou
le plus grand de tous les biens qui concernent le corps, c’est pourtant celui auquel nous faisons le moms de reflexion,
et que nous goutons le moins. Or, la connoissance de la verite est comme la sante de Tame; lorsque on la possede on
u‘y pense plus.”—Lettres, Tome I. Lettre xliii.)
DISSERTATION FIRST.
121
bury ; who, in many parts of the Characteristics, has suggested some of the maxims in his Tract
has ridiculed Locke’s philosophy, and endea- on Education.3 He had been treated, himself,
voured to represent him as a disciple of Hobbes.” it would appear, with very little indulgence by
To those who are aware of the direct opposition his parents; and probably was led by that filial
between the principles of Hobbes, of Montaigne, veneration which he always expressed for their
of Gassendi, and of the other minute philosophers memory, to ascribe to the early habits of self-
with whom Locke sometimes seems unconsci- denial imposed on him by their ascetic system
ously to unite his strength,—and the principles of ethics, the existence of those moral qualities
of Socrates, of Plato, of Cicero, and of all the which he owed to the regulating influence of his
soundest moralists, both of ancient and of mo- own reason in fostering his natural dispositions;
dern times, the foregoing anecdote will serve at and which, under a gentler and more skilful cul-
once to explain and to palliate the acrimony of ture, might have assumed a still more engaging
some of Shaftesbury’s strictures on Locke’s and amiable form. His father, who had served
Ethical paradoxes.1 in the Parliament’s army, seems to have retain-
With this disposition of Locke to depreciate ed through life that austerity of manners which
the ancients, was intimately connected that con- characterised his puritanical associates; and,
tempt which he everywhere expresses for the notwithstanding the comparative enlargement
study of Eloquence, and that perversion of taste and cultivation of Mr Locke’s mind, something
which led him to consider Blackmore as one of of this hereditary leaven, if I am not mistaken,
the first of our English poets.2 That his own continued to operate upon many of his opinions
imagination was neither sterile nor torpid, ap- and habits of thinking. If, in the Conduct of
pears sufficiently from the agreeable colouring the Understanding, he trusted (as many have
and animation which it has not unfrequently thought) too much to nature, and laid too little
imparted to his style : but this power of the mind stress on logical rules, he certainly fell into the
he seems to have regarded with a peculiarly jea- opposite extreme in everything connected with
lous and unfriendly eye ; confining his view ex- the culture of the heart; distrusting nature al-
clusively to its occasional effects in misleading together, and placing his sole confidence in the
the judgment, and overlooking altogether the effects of a systematical and vigilant discipline,
important purposes to which it is subservient, That the great object of education is not to
both in our intellectual and moral frame. Hence, thwart and disturb, but to study the aim, and to
in all his writings, an inattention to those more facilitate the accomplishment of her beneficial
attractive aspects of the mind, the study of which arrangements, is a maxim, one should think,
(as Burke has well observed) <c while it com- obvious to common sense; and yet it is only of
municates to the taste a sort of philosophical late years that it has begun to gain ground even
solidity, may be expected to reflect back on the among philosophers. It is but justice to Rous-
severer sciences some of those graces and ele- seau to acknowledge, that the zeal and ele¬
gancies, without which the greatest proficiency quence with which he has enforced it, go far
in these sciences will always have the appear- to compensate the mischievous tendency of some
ance of something illiberal.” of his other doctrines.
To a certain hardness of character, not unfre- To the same causes it was probably owing,
quently united with an insensibility to the charms that Locke has availed himself so little in his
of poetry and of eloquence, may partly be as- Conduct of the Understanding, of his own favou-
crihed the severe and forbidding spirit which rite doctrine of the Association of Ideas. He
1 Plebeii Philosophi (says Cicero) qui a Platone et Socrate, et ab ea familia dissident.
2 “ All our English poets, except Milton,” says Molyneux in a letter to Locke, “ have been mere ballad-makers in
comparison to Sir Richard Blackmore.” In reply to which Locke says, “ There is, I with pleasure find, a strange har¬
mony throughout between your thoughts and mine.”—(Locke’s Works, Vol. IX. pp. 423, 426.)
3 Such, for example, as this, that “ a child should never be suffered to have what he craves, or so much as speaks for,
much less if he cries for it!” A maxim (as his correspondent Molyneux observes) “ which seems to bear hard on the
tender spirits of children, and the natural affections of parents.”—(Locke’s Works, Vol. IX. p. 319.)
DISS. I. PART II. Q
122
PRELIMINARY DISSERTATIONS.
has been, indeed, at sufficient pains to warn pa¬
rents and guardians of the mischievous conse¬
quences to he apprehended from this part of our
constitution, if not diligently watched over in
our infant years. But he seems to have alto¬
gether overlooked the positive and immense re¬
sources which might he derived from it, in the
culture and amelioration, both of our intellec¬
tual and moral powers;—in strengthening (for
instance), by early habits of right thinking, the
authority of reason and of conscience ;—in blend¬
ing with our best feelings the congenial and
ennobling sympathies of taste and of fancy;—
and in identifying, with the first workings of
the imagination, those pleasing views of the
order of the universe, which are so essentially
necessary to human happiness. A law of our
nature, so mighty and so extensive in its influ¬
ence, was surely not given to man in vain; and
the fatal ■purchase which it has, in all ages, af¬
forded to Machiavellian statesmen, and to poli¬
tical religionists, in carrying into effect their
joint conspiracy against the improvement and
welfare of our species, is the most decisive proof
of the manifold uses to which it might he turn¬
ed in the hands of instructors, well disposed and
well qualified humbly to co-operate with the ob¬
vious and unerring purposes of Divine Wisdom.
A more convenient opportunity will after¬
wards occur for taking some notice of Locke’s
writings on Money and Trade, and on the Prin¬
ciples of Government. They appear to me to
connect less naturally and closely with the li¬
terary history of the times when they appeared,
than with the systematical views which were
opened on the same subjects about fifty years
afterwards, by some speculative politicians in
France and in England. I shall, therefore, de¬
lay any remarks on them which I have to offer
till we arrive at the period when the questions
to which they relate began everywhere to at¬
tract the attention of the learned world, and to
be discussed on those general principles of ex¬
pediency and equity, which form the basis of
the modern science of Political Economy. With
respect to his merits as a logical and metaphysi¬
cal reformer, enough has been already said for
this introductory section : but I shall have oc¬
casion, more than once, to recur to them in the
following pages, when I come to review those
later theories, of which the germs or rudiments
may be distinctly traced in his works; and of
which he is, therefore, entitled to divide the
praise with such of his successors as have rear¬
ed to maturity the prolific seeds scattered by
his hand.1
SECTION II.
Continuation of the Review of Locke and Leibnitz.
LEIBNITZ.
Independently of the pre-eminent rank,
which the versatile talents and the universal
learning of Leibnitz entitle him to hold among
the illustrious men who adorned the Continent
of Europe during the eighteenth century? there
are other considerations which have determin¬
ed me to unite his name with that of Locke, in
fixing the commencement of the period, on the
history of which I am now to enter. The
school of which he was the founder was strong¬
ly discriminated from that of Locke, by the ge¬
neral spirit of its doctrines; and to this school
a large proportion of the metaphysicians, and
also of the mathematicians of Germany, Hol-
1 And yet with what modesty does Locke speak of his own pretensions as a Philosopher! “ In an age that produces such
masters as the great Huygenius and the incomparable Mr Newton, it is ambition enough to be employed as an under¬
labourer in clearing the ground a little, and removing some of the rubbish that lies in the way to knowledge.”—(Estay on
Human Understanding. Epistle to the Reader.) See Note Z.
DISSERTATION FIRST.
123
land, France, and Italy, have ever since his
time had a decided leaning. On the funda¬
mental question, indeed, concerning the Origin
of our Knowledge, the philosophers of the Con¬
tinent (with the exception of the Germans, and
a few eminent individuals in other countries)
have, in general, sided with Locke, or rather
with Gassendi; hut, in most other instances, a
partiality for the opinions, and a deference for
the authority of Leibnitz, may be traced in their
speculations, both on metaphysical and physical
subjects. Hence a striking contrast between
the characteristical features of the continental
philosophy, and those of the contemporary sys¬
tems which have succeeded each other in our
own island; the great proportion of our most
noted writers, notwithstanding the opposition
of their sentiments on particular points, having
either attached themselves, or professed to attach
themselves, to the method of inquiry recom¬
mended and exemplified by Locke.
But the circumstance which chiefly induced
me to assign to Leibnitz so prominent a place
in this historical sketch, is the extraordinary
influence of his industry and zeal, in uniting,
by a mutual communication of intellectual lights
and of moral sympathies, the most powerful
and leading minds scattered over Christendom.
Some preliminary steps towards such an union
had been already taken by Wallis in England,
and by Mersenne in France; but the literary
commerce, of which they were the centres, was
confined almost exclusively to Mathematics and
to Physics; while the comprehensive corre¬
spondence of Leibnitz extended alike to every
pursuit interesting to man, either as a specu¬
lative or as an active being. From this time
forward, accordingly, the history of philosophy
involves, in a far greater degree than at any
former period, the general history of the human
mind; and we shall find, in our attempts to
trace its farther progress, our attention more
and more irresistibly withdrawn from local de¬
tails to more enlarged views of the globe which
we inhabit. A striking change in this literary
commerce among nations took place, at least in
the western parts of Europe, before the death
of Leibnitz; hut, during the remainder of the
last century, it continued to proceed with an
accelerated rapidity over the whole face of the
civilised world. A multitude of causes, un¬
doubtedly, conspired to produce it; hut I know
of no individual whose name is better entitled
than that of Leibnitz, to mark the era of its
commencement.1
I have already, in treating of the philosophy
of Locke, said enough, and perhaps more than
enough, of the opinion of Leibnitz concerning
the origin of our knowledge. Although expressed
in a different phraseology, it agrees in the most
essential points with the innate ideas of the Car¬
tesians ; hut it approaches still more nearly to
some of the mystical speculations of Plato. The
very exact coincidence between the language of
Leibnitz on this question, and that of his con¬
temporary Cudworth, whose mind, like his own,
was deeply tinctured with the Platonic Meta¬
physics, is not unworthy of notice here, as an
historical fact; and it is the only remark on this
part of his system which I mean to add at pre¬
sent to those in the preceding history.
“ The seeds of our acquired knowledge,” says
Leibnitz, “ or, in other words, our ideas, and
the eternal truths which are derived from them,
are contained in the mind itself; nor is this won¬
derful, since we know by our own consciousness,
that we possess within ourselves the ideas of ex¬
istence, of unity, of substance, of action, and other
ideas of a similar nature.” To the same purpose,
we are told by Cudworth, that “ the mind con¬
tains in itself virtually (as the future plant or
tree is contained in the seed) general notions of
all things v/hich unfold and discover themselves
as occasions invite, and proper circumstances
occur.”
The metaphysical theories, to the establish-
1 The following maxims of Leibnitz deserve the serious attention of all who have at heart the improvement of mankind:
“ On trouve dans le monde plusieurs personnes bien intentionnees; mais le mal est, qu’elles ne s’entendent point, et ne
travaillent point de concert. S’il y avoit moyen de trouver une espe'ce de glu pour les reunir, on feroit quelque chpse.
Le mal est souvent que les gens de bien ont quelques caprices ou opinions particulieres, qui font qu’ils sont contraires
entr’eux L’esprit sectaire consiste proprement dans cette pretention de vouloir que les autres se reglent sur noa
maximes, au lieu qu’on se devroit contenter de voir qu’on aille au but principal.”.—(Leib. Op. Tom. I. p. TiO)
124
PRELIMINARY DISSERTATIONS.
ment of which Leibnitz chiefly directed the force
of his genius, are the doctrine of Pre-established
Harmony; and the scheme of Optimism, as new mo¬
delled by himself. On neither of these heads will
it be necessary for me long to detain my readers.
1. According to the system of Pre-established
Harmony, the human mind and human body
are two independent but constantly correspond¬
ent machines ;—adjusted to each other like two
unconnected clocks, so constructed, that, at the
same instant, the one should point the hour, and
the other strike it. Of this system the follow¬
ing summary and illustration are given by Leib¬
nitz himself, in his Essay entitled Theodiccea :
“ I cannot help coming into this notion, that
God created the soul in such manner at first,
that it should represent within itself all the
simultaneous changes in the body; and that he
has made the body also in such manner, as that
it must of itself do what the soul wills :—So that
the laws which make the thoughts of the soul
follow each other in regular succession, must
produce images which shall he coincident with
the impressions made by external objects upon
our organs of sense; while the laws by which
the motions of the body follow each other, are
likewise so coincident with the thoughts of the
soul, as to give to our volitions and actions the very
same appearance, as if the latter were really the
natural and the necessary consequences of the
former.”—(Leib. Op. I. p. 163.) Upon another
occasion he observes, that {£ every thing goes on
in the soul as if it had no body, and that every
thing goes on in the body as if it had no soul.”
{Ibid. II. p. 44.)
To convey his meaning still more fully, Leib¬
nitz borrows from Mr Jaquelot1 a comparison,
which, whatever may he thought of its justness,
must he at least allowed some merit in point of
ingenuity. “ Suppose that an intelligent and
powerful being, who knew, beforehand, every
particular thing that I should order my footman
to do to-morrow, should make a machine to re¬
semble my footman exactly, and punctually to
perform, all day, whatever I directed. On this
supposition, would not my will in issuing all the
details of my orders, remain, in every respect,
in the same circumstances as before? And would
not my machine-footman, in performing his dif¬
ferent movements, have the appearance of acting
only in obedience to my commands ?” The in¬
ference to he drawn from this comparison is,
that the movements of my body have no direct
dependence whatever on the volitions of my
mind, any more than the actions of my machine-
footman would have on the words issuing from
my lips. The same inference is to he extended
to the relation which the impressions made on my
different senses hear to the co-existent percep¬
tions arising in my mind. The impressions and
perceptions have no mutual connection, resembling
that of physical causes with their effects; hut
the one series of events is made to correspond
invariably with the other, in consequence of an
eternal harmony between them pre-established by
their common Creator.
From this outline of the scheme of Pre-establish¬
ed Harmony, it is manifest, that it took its rise
from the very same train of thinking which
produced Malehranche’s doctrine of Occasional
Causes. The authors of both theories saw clearly
the impossibility of tracing the mode in which
mind acts on body, or body on mind; and hence
were led rashly to conclude, that the connection or
union which seems to exist between them is not
real, but apparent. The inferences, however,
which they drew from this common principle
were directly opposite; Malebranche maintain¬
ing, that the communication between mind and
body was carried on by the immediate and in¬
cessant agency of the Deity; while Leibnitz con¬
ceived, that the agency of God was employed
only in the original contrivance and mutual ad¬
justment of the two machines;—all the subsequent
phenomena of each being the necessary results
of its own independent mechanism, and, at the
same time, the progressive evolutions of a com¬
prehensive design, harmonising the laws of the
one with those of the other.
Of these two opposite hypotheses, that of Leib¬
nitz is by far the more unphilosophical and un¬
tenable. The chief objection to the doctrine of
Author of a Book entitled Conformity de la Foi cevec la Raison.
DISSERTATION FIRST.
125
occasional causes is, that it presumes to decide
upon a question of which human reason is alto¬
gether incompetent to judge;—our ignorance of
the mode in which matter acts upon mind, or
mind upon matter, furnishing not the shadow of
a proof that the one may not act directly and
immediately on the other, in some way incom¬
prehensible by our faculties.1 But the doctrine
of Pre-established Harmony, besides being equally
liable to this objection, labours under the ad¬
ditional disadvantage of involving a perplexed
and totally inconsistent conception of the nature
of Mechanism;—an inconsistency, by the way,
with which all those philosophers are j ustly charge¬
able, who imagine that, by likening the universe
to a machine, they get rid of the necessity of
admitting the constant agency of powers essen¬
tially different from the known qualities of mat¬
ter. The word Mechanism properly expresses a
combination of natural powers to produce a cer¬
tain effect. When such a combination is success¬
ful, a machine, once set a-going, will sometimes
continue to perform its office for a considerable
time, without requiring the interposition of the
artist: And hence we are led to conclude, that
the case may perhaps he similiar with respect to
the universe, when once put into motion by the
Deity. This idea Leibnitz carried so far as to
exclude the supposition of any subsequent agency
in the first contriver and mover, excepting in
the case of a miracle. But the falseness of the
analogy appears from this, that the moving force
in every machine is some natural power, such
as gravity or elasticity; and, consequently, the
very idea of mechanism assumes the existence of
those active powers, of which it is the professed
object of a mechanical theory of the universe to
give an explanation. Whether, therefore, with
Malebranche, we resolve every effect into the
immediate agency of God, or suppose, with the
great majority of Newtonians, that he employs
the instrumentality of second causes to accom¬
plish his purposes, we are equally forced to ad¬
mit with Bacon, the necessity not only of a first
contriver and mover, hut of his constant and effi¬
cient concurrence (either immediately or me¬
diately) in carrying his design into execution :—
“ Opus (says Bacon) quod operatur Deus a pri-
mordio usque adJinem.”
In what I have now said I have confined my¬
self to the idea of Mechanism as it applies to the
material universe; for, as to this word, when
1 The mutual action, or (as it was called in the schools) the mutual influence (hfluxus) of soul and body, was, till the
time of Descartes, the prevailing hypothesis, both among the learned and the vulgar. The reality of this influx, if not
positively denied by Descartes, was at least mentioned by him as a subject of doubt; but by Malebranche and Leibnitz it
was confidently rejected as absurd and impossible. (See their works passim.) Gravesande, who had a very strong leaning
towards the doctrines of Leibnitz, had yet the good sense to perceive the inconclusiveness of his reasoning in this particu¬
lar instance, and states in opposition to it the following sound and decisive remarks: “Non concipio, quomodo mens in
corpus agere possit; non etiam video, quomodo ex motu nervi perceptio sequatur; non tamen inde sequi mihi apparet,
omnem influxum esse rejiciendum.
“ Substantim incognitse sunt. Jam videmus naturam mentis nos latere ; scimus hanc esse aliquid, quod ideas habet, has
confert, &c. sed ignoramus quid sit subjeCtum, cui hae proprietates conveniant.
“ Hoc idem de corpore dicimus ; est extensum, impenetrabile, &c. sed quid est quod habet hasce proprietates ? Nulla
nobis via aperta est, qua ad hanc cognitionem pervenire possimus.
“ Inde concludimus, multa nos latere, quae prop^istates mentis et corporis spectant.
“ Invicta demonstratione constat, non mentem in corpus, neque hoc in illam agere, ut corpus in corpus agit; sed mihi
non videtur inde concludi posse, omnem mfluxum esse impossibilem.
“ Motu suo corpus non agit in aliud corpus, sine resistente; sed an non actio, omnino diversa, et cujus ideam non habemus,
m aliam substantiam dari possit, et ita tamen, ut causa effectui respondeat, in re adeo obscura, determinare non ausim.
Difficile certe est influxum negare, quando exacte perpendimus, quomodo in minimis quae mens percipit, relatio detur cum
agitationibus in corpore, et quomodo hujus motus cum mentis determinationibus conveniant. Attendo ad ilia quae medici,
et anatomic!, nos de his docent.
“ Nihil, ergo, de systemate influxus determine, praster hoc, mihi nondum hujus impossibilitatem satis clare demonstratam
esse videri.”—(Introductio ad Philosophiam.) See Note A A.
With respect to the manner in which the intercourse between Mind and Matter is carried on, a very rash assertion escaped
Mr Locke in the first edition of his Essay. “ The next thing to be considered is, how bodies produce ideas in us, and that
is manifestly by impulse, the only way which we can conceive bodies operate in.”—(Essay, B. II. ch. viii. § 11.)
In the course of Locke’s controversial discussions with the Bishop of Worcester, he afterwards became fully sensible of
this important oversight; and he had the candour to acknowledge his error in the following terms : “ ’lis true, I have
said, that bodies operate by impulse, and nothing else. And so I thought when I writ it, and can yet conceive no other
way of their operations. But I am since convinced, by the judicious Mr Newton’s incomparable book^ that it is too bold a
presumption to limit God’s power in this point by my narrow conceptions. *•*»*« And, therefore, in the next edi¬
tion of my book, I will take care to have that passage rectified.” . . .
It is a circumstance that can only be accounted for by the variety of Mr Locke’s other pursuits, that in all the later eoi-
tions of the Essay which have fallen in my way, the proposition in question has been allowed to remain as it originally stood.
126
PRELIMINARY DISSERTATIONS.
applied by Leibnitz to the mind, which he calls
a Spiritual Automaton, I confess myself quite un¬
able to annex a meaning to it: I shall not, there¬
fore, offer any remarks on this part of his sys¬
tem.1
To these visionary speculations of Leibnitz,
a strong and instructive contrast is exhibited in
the philosophy of Locke ; a philosophy, the main
object of which is less to enlarge our knowledge,
than to make us sensible of our ignorance; or
(as the author himself expresses it) “ to prevail
with the busy mind of man to be cautious in
meddling with things exceeding its comprehen¬
sion ; to stop when it is at the utmost extent of
its tether; and to sit down in a quiet ignorance
of those things, which, upon examination, are
found to be beyond the reach of our capacities.”
 <c My right hand writes,” says Locke, in
another part of his Essay, C{ whilst my left hand
is still. What causes rest in one, and motion in
the other ? Nothing but my will, a thought of
my mind; my thought only changing, my right
hand rests, and the left hand moves. This is
matter of fact which cannot he denied. Explain
this and make it intelligible, and then the next
step will be to understand Creation In the
meantime, it is an overvaluing ourselves, to re¬
duce all to the narrow measure of our capaci¬
ties ; and to conclude all things impossible to be
done, whose manner of doing exceeds our com¬
prehension If you do not understand the
operations of your own finite Mind, that think¬
ing thing within you, do not deem it strange
that you cannot comprehend the operations of
that eternal infinite Mind, who made and governs
all things, and whom the heaven of heavens can¬
not contain.”2 3 *—(Yol. II. pp. 249, 250.)
This contrast between the philosophical cha¬
racters of Locke and of Leibnitz is the more de¬
serving of notice, as something of the same sort
has ever since continued to mark and to discri¬
minate the metaphysical researches of the Eng¬
lish and of the German schools. Various ex¬
ceptions to this remark may, no doubt, be men¬
tioned ; but these exceptions will be found of
trifling moment, when compared with the indis¬
putable extent of its general application.
The theory of pre-established harmony led,
by a natural and obvious transition, to the scheme
of Optimism. As it represented all events, both
in the physical and moral worlds, as the neces¬
sary effects of a mechanism originally contrived
and set a-going by the Deity, it reduced its au¬
thor to the alternative of either calling in ques¬
tion the Divine power, wisdom, and goodness,
or of asserting that the universe which he had
called into being was the best of all possible
systems. This last opinion, accordingly, was
eagerly embraced by Leibnitz; and forms the
subject of a work entitled Theodiccea, in which
are combined together, in an extraordinary de¬
gree, the acuteness of the logician, the imagina¬
tion of the poet, and the impenetrable, yet sub¬
lime darkness, of the metaphysical theologian.5
The modification of Optimism, however, adopt¬
ed by Leibnitz, was, in some essential respects,
peculiar to himself. It differed from that of
Plato, and of some other sages of antiquity, in
considering the human mind in the light of a
spiritual machine, and, of consequence, in posi-
1 Absurd as the hypothesis of a Pre-established Harmony may now appear, not many years have elapsed since it was the pre
vailing, or rather universal creed, among the philosophers of Germany. “II fut un temps” (says the celebrated Euler/
“ ou le systeme de Pharmonie pre-etablie etoit tellement en vogue dans toute PAllemagne, que ceux qui en doutoient, pas-
soient pour des ignorans, ou des esprits bornes.”—(Letires de M. Euler d une Princesse d'Allemagne, 83e Lettre.) It would
be amusing to reckon up the succession of metaphysical creeds which have been since swallowed with the same implicit faith
by this learned and speculative, and (in all those branches of knowledge where imagination has no influence over the judg¬
ment) profound and inventive nation.
2 That this is a fair representation of the scope of Locke’s philosophy, according to the author’s own view of it, is demon¬
strated by the two mottos prefixed to the Essay on Human Understanding. The one is a passage of the book of Ecclesiastes,
which, from the place it occupies in the front of his work, may be presumed to express what he himself regarded as the most
important moral to be drawn from his speculations. “ As thou knowest not what is the way of the spirit, nor how the bones
do grow in the womb of her that is with child; even so, thou knowest not the works of God, who maketh all things.” The
other motto (from Cicero) strongly expresses a sentiment which every competent judge must feel on comparing the above quo¬
tations from Locke, with the monads and the pre-established harmony of Leibnitz. “ Qnam bellum est velle confiteri potius
nescire quod nescias, quam ista effutientem nauseare, atque ipsum sibi displicere !” See Note B B.
3 “ La Theodicee seule (says Fontenelle) sufliroit pour representer M. Leibnitz. Une lecture immense, des anecdotes
curieuses sur les livres ou les personnes, beaucoup d’equite et meme de faveur pour tous les auteurs cite's, fut ce en les
combattant; des vues sublimes et lumineuses, des raisonnemens aufond desquelson sent toujours 1’esprit geometrique, un
style ou la force domine, et oil cependant sontadmisles agremens d’une imagination heureuse.”—Eloge de Leibnitz.
DISSERTATION FIRST.
lively denying the freedom of human actions.
According to Plato, every thing is right, so far
as it is the work of God;—the creation of beings
endowed with free will, and consequently liable
to moral delinquency—and the government of
the world by general laws, from which oc¬
casional evils must result,—furnishing no ob¬
jection to the perfection of the universe, to which
a satisfactory reply may not he found in the
partial and narrow views of it, to which our fa¬
culties are at present confined. But he held at
the same time, that, although the permission of
moral evil does not detract from the goodness of
God, it is nevertheless imputable to man as a
fault, and renders him justly obnoxious to
punishment. This system (under a variety of
forms) has been in all ages maintained by the
wisest and best philosophers, who, while they
were anxious to vindicate the perfections of God,
saw the importance of stating their doctrine in
a manner not inconsistent with man’s free will
and moral agency.
The scheme of Optimism, on the contrary, as
127
proposed by Leibnitz, is completely subversive
of these cardinal truths. It was, indeed, view¬
ed by the great and excellent author in a very
different light; hut in the judgment of the most
impartial and profound inquirers, it leads, by a
short and demonstrative process, to the annihi¬
lation of all moral distinctions.1
It is of great importance to attend to the dis¬
tinction between these two systems; because it
has, of late, become customary among sceptical
writers, to confound them studiously together,
in order to extend to both that ridicule to which
the latter is justly entitled. This, in particu¬
lar, was the case with Voltaire, who, in many
parts of his later works, and more especially in
his Candide, has, under the pretence of expos¬
ing the extravagancies of Leibnitz, indulged his
satirical raillery against the order of the uni¬
verse. The success of his attempt was much
aided by the confused and inaccurate manner
in which the scheme of optimism had been re¬
cently stated by various writers, who, in their
zeal to 44 vindicate the ways of God,” had been
1 It is observed by Dr Akenside, that “ the Theory of Optimism has been delivered of late, especially abroad, in a man¬
ner which subverts the freedom of human actions; whereas Plato appears very careful to preserve it, and has been in that re¬
spect imitated by the best of his followers.”—(Notes on the 2d Book of the Pleasures of the Imagination.)
I am perfectly aware, at the same time, that different opinions have been entertained of Plato’s real sentiments on this sub¬
ject ; and I readily grant that passages with respect to Fate and Necessity may be collected from his works, which it would be
very difficult to reconcile with any one consistent scheme—(See the Notes of Mosheimon his Latin Version of Cudworth’s
Intellectual System, Tome. I. pp. 10. 310, et seq. Lugd. Batav. 1773.)
Without entering at all into this question, I may be permitted here to avail myself, for the sake of conciseness, of Plato’s
name, to distinguish that modification of optimism which I have opposed in the text to the optimism of Leibnitz. The follow¬
ing sentence, in the 10th Book De Repuhlica, seems sufficient of itself to authorise this liberty:—'Aeirri Si d.'Sira-oTov, %v riftwv xa)
cc'riy.K^wv, vrAiov xou iAccrrov otvrrts ixaixTos &%u. alrla. iAo[/.tvu. ©sc? avuiTiog. Virtus inviolabilis ac libera quam prout honerabit quis aut
negliget, ita plus aut minus ex eapossidebit. Eligentis quidem culpa est omnis. Deus vero eoctra culpam.
A short abstract of the allegory with which Leibnitz concludes his Theodiccea, will convey a clearer idea of the scope of that
work, than I could hope to do by any metaphysical comment. The groundwork of this allegory is taken from a dialogue
on Free-Will, written by Laurentius Valla, in opposition to Boethius ;—in which dialogue, Sextus, the son of Tarquin
the Proud, is introduced as consulting Apollo about his destiny. Apollo predicts to him that he is to violate Lucretia, and
afterwards, with his family, to be expelled from Home. (Exul inopsque cades irata pulsus ub urbe.J Sextus complains of the
prediction. Apollo replies, that the fault is not his; that he has only the gift of seeing into futurity ; * that all things are
regulated by Jupiter; and that it is to him his complaint should be addressed. (Here finishes the allegory of Valla, which
Leibnitz thus continues, agreeably to his own principles.) In consequence of the advice of the Oracle, Sextus goes to Dodona to
complain to Jupiter of the crime which he is destined to perpetrate. “ Why (says he), oh Jupiter! have you made me
wicked and miserable ? Either change my lot and my will, or admit that the fault is yours, not mine.” Jupiter replies to
him : “ Renounce all thoughts of Rome and of the crown ; be wise, and you shall be happy. If you return to Rome you
are undone.” Sextus, unwilling to submit to such a sacrifice, quits the Temple, and abandons himself to his fate.
After his departure, the high priest, Theodorus, asks Jupiter why he had not given another Will to Sextus.' Jupiter
sends Theodorus to Athens to consult Minerva. The goddess shows him the Palace of the Destinies, where are represen¬
tations of all possible worlds, each of them containing a Sextus Tarquinius with a different Will, leading to a catastrophe
more or less happy. In the last and best of these worlds, forming the summit of the pyramid composed by the others, the
high priest sees Sextus go to Rome, throw every thing into confusion, and violate the wife of his friend. “ You see” (says
the Goddess of Wisdom) “it was not my father that made Sextus wicked. He was wicked from all eternity, and he was
always so in consequence of his own will.J Jupiter has only bestowed on him that existence which he could not refuse him
in the best of all possible worlds. He only transferred him from the region of possible to that of actual beings. What great
* “ Futura novi, non facio.”
-j- World (it must be remembered) is here synonymous with Universe.
$ “ Vides Sextum a Patre meo non fuisse factum improbum, talis quippe ab omni aeternitate fuit, et quidem semper h-
bere; existere tantum ei concessit'Jupiter, quod ipsum profecto ejus sapientia mundo, in quo file continebatur, denegare
non poterat: ergo Sextum e regione possibilium ad rerum existentium classem transtulit.”
128
PRELIMINARY DISSERTATIONS.
led to hazard principles more dangerous in their
consequences, than the prejudices and errors
which it was their aim to correct.1
The zeal of Leibnitz in propagating the dogma
of Necessity is not easily reconcileable with the
hostility which, as I have already remarked, he
uniformly displays against the congenial doctrine
of Materialism. Such, however, is the fact, and
I believe it to be quite unprecedented in the pre¬
vious history of philosophy. Spinoza himself has
not pushed the argument for necessity further
than Leibnitz,—the reasonings of both conclud¬
ing not less forcibly against the free-will of God
than against the free-will of man, and, of con¬
sequence, terminating ultimately in this pro¬
position, that no event in the universe could
possibly have been different from what has actu¬
ally taken place.3 The distinguishing feature of
this article of theLeibnitzian creed is, that, while
the Hobbists and Spinozists were employing their
ingenuity in connecting together Materialism
and Necessity, as branches springing from one
common root, Leibnitz always speaks of the soul
as a machine purely spiritual,5—a machine, how¬
ever, as necessarily regulated by pre-ordained
and immutable laws, as the movements of a clock
or the revolutions of the planets. In consequence
of holding this language, he seemed to represent
Man in a less degrading light than other neces¬
sitarians ; but, in as far as such speculative te-
events does the crime of Sextus draw after it ? The liberty of Rome—the rise of a government fertile in civil and mili¬
tary virtues, and of an empire destined to conquer and to civilise the earth.” Theodorus returns thanks to the goddess,
and acknowledges the justice of Jupiter.
1 Among this number must be included the author of the Essay on Man, who, from a want of precision in his metaphy¬
sical ideas, has unconsciously fallen into various expressions, equally inconsistent with each other and with his own avowed
opinions:
If plagues and earthquakes break not Heaven’s design,
Why then a Borgia or a Catiline ?—
Who knows but He whose hand the lightning forms,
Who heaves old Ocean, and who wings the storms,
Pours fierce ambition on a Caesar’s mind.
Or turns young Ammon loose to scourge mankind ?—.
«***;»*
—The general order since the whole began,
Is kept in Nature, and is kept in Man.
This approaches very nearly to the optimism of Leibnitz, and has certainly nothing in common with the optimism of Plato.
Nor is it possible to reconcile it with the sentiments inculcated by Pope in other parts of the same poem.
What makes all physical and moral ill ?
There deviates Nature, and here wanders Will.
In this last couplet he £eems to admit, not only that Will may wander, but that Nature herself may deviate from the general
order; whereas the doctrine of his universal prayer is, that, while the material world is subjected to established laws, man
is left to be the arbiter of his own destiny :
Yet gav’st me in this dark estate
To know the good from ill,
And, binding Nature fast in fate,
Left free the human will.
In the Dunciad, too, the scheme of Necessity is coupled with that of Materialism, as one of the favourite doctrines of the sect
of free-thinkers.
Of nought so certain as our Reason still,
Of nought so doubtful as of Soul and Will.
“ Two things” (says Warburton, who professes to speak Pope’s sentiments) “ the most self-evident, the existence of our
souls and the freedom of our will!”
2 So completely, indeed, and so mathematically linked, did Leibnitz conceive all truths, both physical and moral, to be
with each other, that he represents the eternal geometrician as incessantly occupied in the solution of this problem,— The
State of one Monad (or elementary atom) being given, to determine the state, past, present, and future, of the whole universe.
3 “ Cuncta itaque in homine certa sunt, et in antecessum determinata, uti in caeteris rebus omnibus, et anima humana
est spiriluale quoddam automatum."—Leib. Op. Tom. I. p. 156.
In a note on this sentence, the editor quotes a passage from Bilfinger, a learned German, in which an attempt is made to
vindicate the propriety of the phrase, by a reference to the etymology of the word automaton. This word, it is observed, when
traced to its source, literally expresses something which contains within itself its principle of motion, and, consequently, it ap¬
plies still more literally to Mind than to a machine. The remark, considered in a philological point of view, is indisputably
just; but is it not evident, that it leads to a conclusion precisely contrary to what this author would deduce from it ? What¬
ever may have been the primitive meaning of the word, its common, or rather its universal meaning, even among scientific
writers, is, a material machine, moving without any foreign impulse; and, that this was the idea annexed to it by Leibnitz,
appears from his distinguishing it by the epithet spirituale, an epithet which would have been altogether superfluous had he
intended to convey the opinion ascribed to him by Bilfinger. In applying, therefore, this language to the mind, we may
conclude, with confidence, that Leibnitz had no intention to contrast together mind and body, in respect of their moving or
actuating principles, but only to contrast them in respect of the substances of which they are composed. In a word, he con¬
ceived both of them to be equally machines, made and wound up by the Supreme Being; but the machinery in the one case to
be material, and in the other spiritual.
s
DISSERTATION FIRST.
129
nets may be supposed to have any practical ef¬
fect on human conduct, the tendency of his doc¬
trines is not less dangerous than that of the most
obnoxious systems avowed by his predecessors.1
The scheme of necessity was still farther adorn¬
ed and sublimed in the Theodiccea of Leibnitz,
by an imagination nurtured and trained in the
school of Plato. “ May there not exist,” he asks
on one occasion, t£an immense space beyond the
region of the stars ? and may not this empyreal
heaven be filled with happiness and glory ? It
may be conceived to resemble an ocean, where
the rivers of all those created beings that are des¬
tined for bliss shall finish their course, when
arrived in the starry system, at the perfection of
their respective natures.”—(Leib. Op. Tom. I.
p. 135.)*
In various other instances, he rises from the
deep and seemingly hopeless abyss of Fatalism,
to the same lofty conceptions of the universe;
and has thus invested the most humiliating article
of the atheistic creed, with an air of Platonic
mysticism. The influence of his example appears
to me to have contributed much to corrupt the
taste and to bewilder the speculations of his coun¬
trymen ; giving birth, in the last result, to that
heterogeneous combination of all that is pernicious
in Spinozism, with the transcendental eccentrici¬
ties of a heated and exalted fancy, which, for
many years past, has so deeply tinctured both
their philosophy and their works of fiction.5
In other parts of Europe, the effects of the Theo-
diccBa have not been equally unfavourable. In
France, more particularly, it has furnished to
the few who have cultivated with success the
Philosophy of Mind, new weapons for combat¬
ing the materialism of the Gassendists and Hob-
bists; and, in England, we are indebted to it for
the irresistible reasonings by which Clarke sub¬
verted the foundations on which the whole su¬
perstructure of Fatalism rests.4
It may be justly regarded as a proof of the
i The following remark in Madame de Stael’s interesting and eloquent review of German philosophy bears marks of e
haste and preeipitatmn wuh which her criticisms are seldom chargeable: “ Les opinions de Leibnitz tendent surtout ac
l°n.nement nu^a1’ 8 11 ^ vra1’ comme les philosophes Allemands ont tache de le prouver, que le libre arbitre repos
du vouloir ” 11111 affianchlt 1 ame des obJets exteneures, et que la vertu ne puisse exister sans la parfaite independanc
fnllmvint Charles B™net' V? his work entitled, Contemplation de la Nature, has indulged his imagination so far, in
o ing out the above conjecture of Leibnitz, as to rival some of the wildest flights of Jacob Behmen. “ Mais I’e'chelle
it npnfn10!1'116 i? t®r“ine.Point,au P*us elevds des mondes planetaires. La commence un autre univers, dont 1’etendue
est peut-etre a celle de 1 univers des Fixes, ce qu’est I’espace du syste'me solaire a la capacite d’une noix.
IjR, comme des Astres resplendissans, brillent les Hierarchies Celestes.
d? t0£tes parts les ArGL;>’ les Auciianoes’ les Serafhins, les Chehtjb!ns, les Tuones, les Verttjs,
les Brincipautes, les Dominations, les Puissances.
“Au centre de ces Augustes Spheres, delate le Soleie de Justice, l’Orient d’Enhaut, dont tous les Astres
empruntent leur lumiere et leur splendeur.”
“ La Theodicte de Leibnitz,” the same author tells us m another passage, “ est un de mes livres de devotion : J’ai intitule
mon Exemplaire, Manuel de Philosophic Chretienne." muuuc
gr.oss appetHe of Love (says Gibbon) becomes most dangerous when it is elevated, or rather disguised, by sen¬
timental passion. The remark is strikingly applicable to some of the most popular novels and dramas of Germany; and
something very similar to it will be found to hold with respect to those speculative extravagancies which, in the German
systems ot philosophy, are elevated or disguised by the imposing cant of moral enthusiasm.
, .on0 ot Leibnitz’s controversial discussions with Dr Clarke, there is a passage which throws some light on his taste, not
only m matters of science, but in judging of works of imagination. “ Du temps de M. Boyle, et d’autres excellens homines
qui lleurissoient en Angleterre sous Charles II. on n’auroit pas ose nous debiter des notions si crenses. (The notions here al¬
luded to are those of Newton concerning the law of gravitation.) J’espcre que le beautemps reviendra sous un aussi bon enu-
vernement que celui d a present. Le capital de M. Boyle etoit d’inculquer que tout se faisoit mechaniquement dans la phy¬
sique. Mais c est un malheur des hommes, de se degouter enfin de la raison meme, et de s’ennuyer de la lumiere. Les
clnmeres commencent a revenir, et plaisent parce' qu’elles ont quelque chose de merveilleux. II arrive dans le pays philo-
sophique ce qui est arrive dans le pays poetique. On s’est lasse' des romans raisonnables, tel que la Clelie Francoise ou
l Aramene Allemande; et on est revenu depuis quelque temps aux Contes des Fles."—(Cinquieme Ecrit de M. Leibnitz p. 260.)
b rom this passage it would seem, that Leibnitz looked forward to the period, when the dreams of the Newtonian philo¬
sophy would give way to some of the exploded mechanical theories of the universe ; and when the Fairy-tales then in fa¬
shion (among which number must have been included those of Count Anthony Hamilton) would be supplanted by the re¬
vival ot such reasonable Romancesfs the Grand Clelia. In neither of these instances does there seem to be much probability,
at present, that his prediction will be ever verified. 1
i lbej<^.ri?a? wl'!ter‘Vvho, of late years> have made the greatest noise among the sciolists of this country, will be found
m ^‘Zni l0r 1 ,r. fai”e t0 the new which they have struck out, than to the unexpected and grotesque forms in
Hinch they have combined together the materials supplied by the invention of former ages, and of other nations. It is this
'° ^ru ,an(^ error their philosophical systems, and of right and wrong in their works of fiction, which has
enabled them to perplex the understandings, and to unsettle the principles of so many, both in Metaphysics and Ethics,
n pom o proiound and extensive erudition, the scholars of Germany still continue to maintain their long established su¬
periority over the rest of Europe. s
A very inteiesting account is given by Leibnitz, of the circumstances which gave occasion to his Theodiccea. in a letter
DISS. I. PART II. I:
130
PRELIMINARY DISSERTATIONS.
progress of reason and good sense among
the Metaphysicians of this country since the
time of Leibnitz, that the two theories of which
I have been speaking, and which, not more than
a century ago, were honoured by the opposition
of such an antagonist as Clarke, are now re¬
membered only as subjects of literary history.
In the arguments, however, alleged in support of
these theories, there are some logical principles
involved, which still continue to have an ex¬
tensive influence over the reasonings of the
learned, on questions seemingly the most remote
from all metaphysical conclusions. The two
most prominent of these are, the principle of
the Sufficient Reason, and the Law of Continuity ;
both of them so intimately connected with some
of the most celebrated disputes of the last cen¬
tury, as to require a more particular notice than
may, at first sight, seem due to their importance.
I. Of the principle of the Sufficient Reason,
the following succinct account is given by Leib¬
nitz himself, in his controversial correspondence
with Dr Clarke: “ The great foundation of
Mathematics is the principle of contradiction or
identity; that is, that a proposition cannot be
true and false at the same time. But, in order
to proceed from Mathematics to Natural Philo¬
sophy, another principle is requisite (as I have
observed in my Theodiccea); I mean, the prin¬
ciple of the Sufficient Reason ; or, in other words,
that nothing happens without a reason why it
should be so, rather than otherwise : And, ac¬
cordingly, Archimedes was obliged, in his book
De JEquilibrio, to take for granted, that if there
be a balance, in which every thing is alike on
both sides, and if equal weights are hung on the
two ends of that balance, the whole will be at
rest. It is because no reason can be given why
one side should weigh down rather than the
other. Now, by this single principle of the
Sufficient Reason, may be demonstrated the being
of a God, and all the other parts of Metaphysics
or Natural Theology; and even, in some measure,
those physical truths that are independent of
Mathematics, such as the Dynamical Principles,
or the Principles of Forces.”
to a Scotch gentleman, Mr Burnet of Kemney ; to whom he seems to have unbosomed himself on all subjects without any
reserve: “ Mon livre intitule' Essais de Theodicee, sur la bonte de Dieu, la liberte de I’homme, et 1’origine de mal, sera
bientot acheve. La plus grande partie de cet ouvrage avoit ete' faite par lambeaux, quand je me trouvois chez la feue Heine
de Prusse, oil ces matieres dtoient souvent agite'es a 1’occasion du Dictionnaire et des autres ouvrages de M. Bayle, qu’on
y lisoit beaucoup. Apres la mort de cette grande Princesse, j’ai rassemble' et augments ces pie'ces sur Pexhortation des
amis qui en e'toient informes, et j’en ai fait Pouvrage dont je viens de parler. Comme j’ai medite' sur cette matiere depuis
ma jeunesse, je pretends de Pavoir discutee a fond.”—(Leibnitz, Opera, Tom. VI. p. 284.)
In another letter to the same correspondent, he expresses himself thus: /
“ La plupart de mes sentimens ont e'te' enfin arrete's apres une deliberation de 20 ans: car j’ai commence bien jeune a
mediter, et je n’avois pas encore 15 ans, nuand je me promenois des journees entieres dans un bois, pour prendre parti entre
Aristote et Lemocrite. Cependant j’ai change et rechange sur des nouvelles lumieres, et ce n’est que depuis environ 12 ans
que je me trouve satisfait, et que je suis arrive a des demonstrations sur ces matieres qui n en paroissent point capables :
Cependant de la maniere que je m’y prends, ces demonstrations peuvent etre sensibles comme cedes des nombres, quoique
le sujet passe 1’imagination.”—(Ibid. p. 253.)
The letter from which this last paragraph is taken is dated in the year 1697>
My chief reason for introducing these extracts, was to do away an absurd suspicion, which has been countenanced by
some respectable writers (among others bv Le Clerc), that the opinions maintained in the Theodicee of Leibnitz were not
his real sentiments, and that his own creed, on the most important questions there discussed, was not very different from
that of Bayle. Gibbon has even gone so far as to say, that “ in his defence of the attributes and providence of the Deity,
he was suspected of a secret correspondence with his adversary.”—(Antiquities of the House of Brunswick.) In support of
this very improbable charge, I do not know that any evidence has ever been produced, except the following passage, in a letter
of his, addressed to a Professor of Theology in the University of Tubingen (Pfaffius):—“ Ita prorsus est, vir summe re-
verende, uti scribis, de Theodicaea mea. Item acu tetigisti; et miror, neminem hactenus fuisse, qui sensum hunc meum
senserit. Neque enim Philosophorum est rem serio semper agere ; qui in fingendis hypothesibus, uti bene mones, ingenii
sui vires experiuntur. Tu, qui Theologus, in refutandis erroribus Theologum agis.” In reply to this it is observed, by
the learned editor of Leibnitz’s works, that it is much more probable that Leibnitz should have expressed himself on this
particular occasion in jocular and ironical terms, than that he should have wasted so much ingenuity and learning in sup¬
port of an hypothesis to which he attached no faith whatever; an hypothesis, he might have added, with which the whole
principles of his philosophy are systematically, and, as he conceived, mathematically connected. It is difficult to believe,
that among the innumerable correspondents of Leibnitz, he should have selected a Professor of Theology at Tubingen, as
the sole depository of a secret which he was anxious to conceal from all the rest of the world.
Surely a solitary document such as this weighs less than nothing, when opposed to the details quoted in the beginning of
this note; not to mention its complete inconsistency with the character of Leibnitz, and with the whole tenor of his
writings.
For my own part, I cannot help thinking, that the passage in question has far more the air of persiflage provoked by
the vanity of Pfaffius, than of a serious compliment to his sagacity and penetration. No injunction to secrecy, it is to
be observed, is here given by Leibnitz to his correspondent.
DISSERTATION FIRST.
131
¥
\
Some of the inferences deduced by Leibnitz
from this almost gratuitous assumption are so
paradoxical, that one cannot help wondering he
was not a little staggered about its certainty.
Not only was he led to conclude, that the mind
is necessarily determined in all its elections by
the influence of motives, insomuch that it would
be impossible for it to make a choice between two
things perfectly alike; but he had the boldness
to extend this conclusion to the Deity, and to
assert, that two things perfectly alike could not
have been produced even by Divine Power. It
was upon this ground that he rejected a vacuum^
because all the parts of it would be perfectly
like to each other; and that he also rejected the
supposition of atoms, or similar particles of mat¬
ter, and ascribed to each particle a monad, or
active principle, by which it is discriminated
from every other particle.1 The application of
his principle, however, on which he evidently
valued himself the most, was that to which I
have already alluded; the demonstrative evidence
with which he conceived it to establish the
impossibility of free-agency, not only in man,
but in any other intelligent being :8 a conclusion
which, under whatever form of words it may he
disguised, is liable to every objection which can
be urged against the system of Spinoza.
With respect to the principle from which these
important consequences were deduced, it is ob¬
servable, that it is stated by Leibnitz in terms
so general and vague, as to extend to all the
different departments of our knowledge; for he
tells us, that there must be a sufficient reason for
every existence, for every event, and for every
truth. This use of the word reason is so extreme¬
ly equivocal, that it is quite impossible to annex
any precise idea to the proposition. Of this it
is unnecessary to produce any other proof than
the application which is here made of it to things
so very different as existences, events, and truths;
in all of which cases, it must of necessity have
different meanings. It would be a vain attempt,
therefore, to combat the maxim in the form in
which it is commonly appealed to: Nor, indeed,
can we either adopt or reject it, without con¬
sidering particularly how far it holds in the va¬
rious instances to which it may be applied.
The multifarious discussions, however, of a phy¬
sical, a metaphysical, and a theological nature,3
necessarily involved in so detailed an examina¬
tion, would, in the present times (even if this
were a proper place for introducing them), be
equally useless and uninteresting; the peculiar
opinions of Leibnitz on most questions connect¬
ed with these sciences having already fallen into
complete neglect. But as the maxim still con¬
tinues to be quoted by the latest advocates for
the scheme of necessity, it may not be altogether
superfluous to observe, that, when understood
to refer to the changes that take place in the
material universe, it coincides entirely with the
common maxim, that “ every change implies
the operation of a cause and that it is in con¬
sequence of its intuitive evidence in this particu¬
lar case, that so many have been led to acquiesce
in it, in the unlimited terms in which Leibnitz
has announced it. One thing will be readily
• See Note CC.
2 The following comment on this part of the Leibnitzian system is from the pen of one of his greatest admirers, Charles
Bonnet: “ Cette Metaphysique transcendante deviendra un peu plus intelligible, si Ton fait attention, qu’en vertu du
principe de la raison suffisante, tout est necessairement lid dans I’univers. Toutes les Actions des Etres Simples sont har-
moniques, ou subordonnees les unes aux autres. L’exercice actuel de 1’activite d’une monade donnee, est determine par
1’exercice actuel de 1’activite des monades auxquelles elle correspond immediatement. Cette correspondance continue d’un
point quelconque de Punivers jusqu’a ses extremitds. Representez-vouz les ordres circulaires et concentriques qu’une
pierre excite dans une eau dormante : Elies vont toujours en s’dlargissant et en s’affoiblissant.
“ Mais, Petat actuel d’une monade est necessairement determine par son dtat antecedent: Celui-ci par un etat qui a
precedd, et ainsi en remontant jusqu’a Pinstant de la creation. ******
“ Ainsi le passe, le prdsent, et le futur ne forment dans la meme monade qu’une seul chaine. Notre philosophe disoit
ingdnieusement, que le present est toujours gros de Vavenir.
“ II disoit encore que PEternel Gedmetre resolvoit sans cesse ce Probleme; Pdtat d’une monade dtant donnd, en ddter-
miner Pdtat passd, prdsent, et futur de tout Punivers.”—Bonnet, Tom. VIII. p. 303, 304, 305.)
3 Since the time of Leibnitz, the principle of the sufficient reason has been adopted by some mathematicians as a legiti¬
mate mode of reasoning in plane geometry ; in which case, the application made of it has been in general just and logical,
notwithstanding the vague and loose manner in which it is expressed. In this science, however, the use of it can never be
attended with much advantage; except perhaps in demonstrating a few elementary truths (such as the 5th and 6th propo¬
sitions of Euclid’s first book), which are commonly established by a more circuitous process : and, even in these instances,
the spirit of the reasoning might easily be preserved under a different form, much less exceptionable in point of phraseology.
132
PRELIMINARY DISSERTATIONS.
granted, that the maxim, when applied to the
determinations of intelligent and moral agents^
is not quite so obvious and indisputable, as when
applied to the changes that take place in things
altogether inanimate and passive.
What then, it may he asked, induced Leibnitz,
in the enunciation of his maxim, to depart from
the form in which it has generally been stated,
and to substitute, instead of the word cause, the
word reason, which is certainly not only the more
unusual, but the more ambiguous expression of
the two ? Was it not evidently a perception of
the impropriety of calling the motives from
which we act the causes of our actions; or, at
least of the inconsistency of this language with
the common ideas and feelings oi mankind ?
The word reason is here much less suspicious,
and much more likely to pass current without
examination. It was therefore with no small
dexterity, that Leibnitz contrived to express his
general principle in such a manner, that the
impropriety of his language should he most ap¬
parent in that case in which the proposition is
instantaneously admitted by every reader as self-
evident ; and to adapt it, in its most precise and
definite shape, to the case in which it was in the
greatest danger of undergoing a severe scrutiny.
In this respect, he has managed his argument
with more address than Collins, or Edwards, or
Hume, all of whom have applied the maxim to
mind, in the very same words in which it is
usually applied to inanimate matter.
But on this article of Leibnitz’s philosophy,
which gave occasion to his celebrated controversy
with Clarke, I shall have a more convenient op¬
portunity to offer some strictures, when I come to
take notice of another antagonist, more formi¬
dable still, whom Clarke had soon after to contend
with on the same ground. The person I allude to
is Anthony Collins, a writer certainly not once
to be compared with Leibnitz, in the grasp of
his intellectual powers ; but who seems to have
studied this particular question with greater at¬
tention and accuracy, and who is universally al¬
lowed to have defended his opinions concerning
it in a manner far more likely to mislead the opi¬
nions of the multitude.
II. The same remark which has been already
made on the principle of the Sufficient Reason
may he extended to that of the Law of Continui¬
ty. In both instances the phraseology is so in¬
determinate, that it may he interpreted in vari¬
ous senses essentially different from each other ;
and, accordingly, it would he idle to argue
against either principle as a general theorem,
without attending separately to the specialties of
the manifold cases which it may he understood
to comprehend. Where such a latitude is taken
in the enunciation of a proposition, which, so
far as it is true, must have been inferred from
an induction of particulars, it is at least possible
that, while it holds in some of its applications, it
may yet he far from possessing any claim to that
universality which seems necessarily to belong
to it, when considered in the light of a metaphy¬
sical axiom, resting on its own intrinsic evi¬
dence.
Whether this vagueness of language was the
effect of artifice, or of a real vagueness in the
author’s notions, may perhaps he doubted; but
that it has contributed greatly to extend his re¬
putation among a very numerous class of readers,
may be confidently asserted. The possession
of a general maxim, sanctioned by the authori¬
ty of an illustrious name, and in which, as in
those of the schoolmen, more seems to he meant
than meets the ear, affords of itself no slight
gratification to the vanity of many; nor is it
inconvenient for a disputant, that the maxims to
which he is to appeal should he stated in so du¬
bious a shape, as to enable him, when pressed
in an argument, to shift his ground at pleasure,
from one interpretation to another. The extra¬
ordinary popularity which, in our own times,
the philosophy of Kant enjoyed, for a few years,
among the countrymen of Leibnitz, may, in like
manner, be in a great degree ascribed to the
imposing aspect of his enigmatical oracles, and
to the consequent facility of arguing without end,
in defence of a system so transmutable and so
elusive in its forms.
The extension, however, given to the Law of
Continuity, in the later publications of Leibnitz,
and still more by some of his successors, has
been far greater than there is any reason to
think was originally in the author’s contempla¬
tion. It first occurred to him in the course of one
of his physical controversies, and was probably
DISSERTATION FIRST.
133
suggested by the beautiful exemplifications of it
which occur in pure geometry. At that time it
does not appear that he had the slightest idea of its
being susceptible of any application to the ob¬
jects of natural history; far less to the succes¬
sion of events in the intellectual and moral
worlds. The supposition of bodies perfectly
hard, having been shown to be inconsistent with
two of his leading doctrines, that of the constant
maintenance of the same quantity of force in
the Universe, and that of the proportionality of
forces to the squares of the velocities,—he found
himself reduced to the necessity of asserting,
that all changes are produced by insensible gra¬
dations, so as to render it impossible for a body
to have its state changed from motion to rest, or
from rest to motion, without passing through all
the intermediate states of velocity. From this
assumption he argued, with much ingenuity,
that the existence of atoms, or of perfectly hard
bodies, is impossible; because, if two of them
should meet with equal and opposite motions,
they would necessarily stop at once, in violation
of the law of continuity. It would, perhaps,
have been still more logical, had he argued
against the universality of a law so gratuitously
assumed, from its incompatibility with an hypo¬
thesis, which, whether true or false, certainly
involves nothing either contradictory or impro¬
bable : but as this inversion of the argument
would have undermined some of the fundamental
principles of his physical system, he chose ra¬
ther to adopt the other alternative, and to an¬
nounce the law of continuity as a metaphysical
truth, which admitted of no exception whatever.
The facility with which this law has been adopt¬
ed by subsequent philosophers is not easily ex¬
plicable ; more especially, as it has been main¬
tained by many who reject those physical errors,
in defence of which Leibnitz was first led to
advance it.
One of the earliest, and certainly the most
illustrious, of all the partizans and defenders of
this principle, was John Bernouilli, whose dis¬
course on motion first appeared at Paris in 1727,
having been previously communicated to the
Royal Academy of Sciences, in 1724 and 1726.1
It was from this period it began to attract the
general attention of the learned; although many
years were yet to elapse, before it was to ac¬
quire that authority which it now possesses
among our most eminent mathematicians.
Mr Maclaurin, whose Memoir on the Percus¬
sion of Bodies gained the prize from the Royal
Academy of Sciences, in 1724, continued from
that time, till his death, the steady opposer of
this new lawt. In his Treatise of Fluxions, pub¬
lished in 1742, he observes, that “ the existence
of hard bodies void of elasticity has been reject¬
ed for the sake of what is called the Law of
Continuity ; a law which has been supposed to be
general, without sufficient ground.” 2 And still
more explicitly, in his Posthumous Account of
Newton's Philosophical Discoveries, he complains
of those who “ have rejected hard bodies as im¬
possible, from far-fetched and metaphysical con¬
siderationsproposing to his adversaries this
unanswerable question, “ Upon what grounds
is the law of continuity assumed as an universal
law of nature ?”s
1 “ En effet (says Bernouilli), un pareil principe de duretd (the supposition to wit of bodies perfectly hard) ne scauroit
exister ; c’est une chimere qui repugne a cette loi generale que la nature observe constarament dans toutes ses operations ;
je parle de cet ordre immuable et perpe'tuel etabli depuis la creation de Punivers, qu'on pent appeller nor de continuite,
en vertu de laquelle tout ce qui s’execute, s’execute par des degres infiniment petits. II semble que le bon sens dicte,
qu’aucun changement ne peut se faire par saut; natura non opcratur per saltum; rien ne peut passer d’une extremite a
Pautre, sans passer par tous les degres du milieu,” &c. The continuation of this passage (which I have not room to quote)
is curious, as it suggests an argument, in proof of the law of continuity, from the principle of the sufficient reason.
It may be worth while to observe here, that though, in the above quotation, Bemouilli speaks of the law of continuity as
an arbitrary arrangement of the Creator, he represents, in the preceding paragraph, the idea of perfectly hard bodies, as in¬
volving a manifest contradiction.
2 Maclaurin’s Fluxions, Vol. II. p. 438.
s Nearly to the same purpose Mr llobms, a mathematician and philosopher of the highest eminence, expresses himself
thus : “ M. Bernouilli (in his Discours sur les Lois de la Communication du Mouvement), in order to prove that there are no
bodies perfectly hard and inflexible, lays it down as an immutable law of nature, that no body can pass from motion to rest
instantaneously, or without having its velocity gradually diminished. That this is a law of nature, M. Bernouilli thinks is
evident from that principle, Natura non operatur per saltum, and from good sense. But how good sense can, of itself,
WITHOUT EXPERIMENT, DETERMINE ANY OF THE LAWS OF NATURE, IS TO ME VERY ASTONISHING. Indeed, from any
thing M. Bernouilli has said, it would have been altogether as conclusive to have begun at the other end, and have disput.
134
PRELIMINARY DISSERTATIONS.
In the speculations hitherto mentioned, the
law of continuity is applied merely to such suc¬
cessive events in the material world as are con¬
nected together hy the relation of cause and
effect; and, indeed, chiefly to the changes which
take place in the state of bodies with respect
to motion and rest. But in the philosophy of
Leihnitz, we find the same law appealed to as
an indisputable principle in all his various re¬
searches, physical, metaphysical, and theologi¬
cal. He extends it with the same confidence to
mind as to matter, urging it as a demonstrative
proof, in opposition to Locke, that the soul never
ceases to think even in sleep or in deliquium ;1 nay,
inferring from it the impossibility that, in the
case of any animated being, there should he
such a thing as death, in the literal sense of
that word.2 It is hy no means probable that
the author was at all aware, when he first intro¬
duced this principle into the theory of motion,
how far it was to lead him in his researches con¬
cerning other questions of greater moment; nor
does it appear that it attracted much notice from
the learned, but as a new mechanical axiom, till
a considerable time after his death.
Charles Bonnet of Geneva, a man of unques¬
tionable talents and of most exemplary worth,
was, as far as I know, the first who entered
fully into the views of Leihnitz on this point;
perceiving how inseparably the law of con¬
tinuity (as well as the principle of the suffi¬
cient reason) was interwoven with his scheme of
universal concatenation and mechanism; and
inferring from thence not only all the paradoxi¬
cal corollaries deduced from it hy its author,
hut some equally hold conclusions of his own,
which Leihnitz either did not foresee in their full
extent, or to which the course of his inquiries
did not particularly attract his attention. The
most remarkable of these conclusions was, that
all the various beings which compose the uni¬
verse, form a scale descending downwards with¬
out any chasm or saltus, from the Deity to the
simplest forms of unorganised matter;3 a pro¬
position not altogether new in the history of
philosophy, hut which I do not know that any
writer before Bonnet had ventured to assert as
a metaphysical and necessary truth. With what
important limitations and exceptions it must
he received, even when confined to the compa-
ed, that no body can pass instantaneously from motion to rest; because it is an immutable law of nature that all bodies
shall be flexible.”—(Robins, Vol. II. p. 174. 175-)
In quoting these passages, I would not wish to be understood as calling in question the universality of the Law of Con¬
tinuity in the phenomena of moving bodies; a point on which I am not led by the subject of this discourse to offer any
opinion; but on which I intend to hazard some remarks in a Note at the end of it—See Note LD. All that I would here
assert is, that it is a law, the truth of which can be inferred only by an induction from the phenomena; and to which, ac¬
cordingly, we are not entitled to say that there cannot possibly exist any exceptions.
1 “ Je tiens que 1’ame, et mcme le corps, n’est jamais sans action, et que Fame n’est jamais sans quelque perception ;
meme en dormant on a quelque sentiment confus et sombre du lieu oil Ton est, et d’autres choses. Mais quand l'experience
ne le confirmeroit pas, je crois qu'il y en a demonstration. C’est a peu pres comme on ne scauroit prouver absolument par les
experiences, s’il n’y a point de vuide dans I’espace, et s’il n’y a point de repos dans la matiere. Et cependant ces questions
me paroissent decidees demonstrativement, aussi bien qu’k M. Locke.”—(Leib. Op. Tome II. p. 220.)
2 See Note EE.
3 “ Leibnitz admettoit comme un principe fondamental de sa sublime philosophie, qu’il n’y a jamais de sauts dans la
nature, et que tout est continu ou nuancd dans le physique et dans le moral. C’etoit sa fameuse Loi de Continuity,
qu’il croyoit retrouver encore dans les mathematiques, et q’avoit ete cette loi qui lui avoit inspird la singuliere pre¬
diction dont je parlois.”* “ Tous les etres, disoit il, ne forment qu’une seule chaine, dans laquelle les differentes classes,
comme autant d’anneaux, tiennent si dtroitement les unes aux autres, qu’il est impossible aux sens et a rimagination de
fixer preaisdment le point oil quelqu’un commence ou finit: toutes les especes qui bordent ou qui occupent, pour ainsi
dire, les regions d’inflection, et de rebroussement, devoit etre Equivoques et doudes de caracteres qui peuvent se rapporter
aux especes voisins dgalement. Ainsi, 1’existence des zoophytes ou Plant-Animaux n’a rien de monstrueux ; mais il est
meme convenable a 1’ordre de la nature qu’il y en ait. Et telle est la force du principe de continuitd chez moi, que non
seulement je ne serois point dtonnd d’apprendre, qu’on eut trouvd des etres, qui par rapport a plusieurs propridtds, par
exemple, celle de se nourrir ou de se multiplier, puissent passer pour des vegdtaux a aussi bon droit que pour des
animaux, . . . J’en serois si peu dtonnd, dis-je, que meme je suis convaincu qu’il doit y en avoir de tels, que 1’Histoire
Naturelle parviendra peut-efre a connoitre un jour,” &c. &c (Contemplation de la Nature, pp. 341. 342.)
Bonnet, in the sequel of this passage, speaks of the words of Leibnitz, as a prediction of the discovery of the Polypus,
deduced from the Metaphysical principle of the Law of Continuity. But would it not be more philosophical to regard
it as a query founded on the analogy of nature, as made known to us by experience and observation ?j-
* I,a prediction de la ddcouverte des Polypes.
+ Ad eum modum summus opifex rerum seriem concatenavit a planta ad hominem, ut quasi sine ullo cohoereant
intervallo ; sic ZuoQvra cum plantis bruta conjungunt; sic cum homine simia quadrupedes. Itaque in hominis quaque
specie invenimus divinos, humanos, feros—Scaliger, (prefixed as a motto to Mr White’s Essay on the regular gradation
in Man- London, 1799-)
DISSERTATION FIRST.
135
rative anatomy of animals, has been fully de¬
monstrated by Cuvier;1 and it is of material
consequence to remark, that these exceptions,
how few soever, to a metaphysical principle, are
not less fatal to its truth than if they exceeded in
number the instances which are quoted in sup¬
port of the general rule.*
At a period somewhat later, an attempt has
been made to connect the same law of continuity
with the history of human improvement, and
more particularly with the progress of invention
in the sciences and arts. Helvetius is the most
noted writer in whom I have observed this last
extension of the Leibnitzian principle; and I
have little doubt, from his known opinions, that,
when it occurred to him, he conceived it to af¬
ford a new illustration of the scheme of necessi¬
ty, and of the mechanical concatenation of all
the phenomena of human life. Arguing in sup¬
port of his favourite paradox concerning the ori¬
ginal equality of all men in point of mental capa¬
city, he represents the successive advances made
by different individuals in the career of discovery,
as so many imperceptible or infinitesimal steps,
each individual surpassing his predecessor by a
trifle, till at length nothing is wanting but an
additional mind, not superior to the others in
natural powers, to combine together, and to
turn to its own account, their accumulated la¬
bours. <c It is upon this mind,” he observes,
il that the world is always ready to bestow the
attribute of genius. From the tragedies of The
Passion, to the poets Hardy and Rotrou, and to
the Mariamne of Tristan, the French theatre
was always acquiring successively an infinite
number of inconsiderable improvements. Cor¬
neille was horn at a moment, when the addition
he made to the art could not fail to form an
epoch; and accordingly Corneille is universally
regarded as a Genius. I am far from wishing,”
Helvetius adds, “ to detract from the glory of
this great poet. I wish only to prove, that Na¬
ture never proceeds per saltum, and that the Law
of Continuity is always excwtly observed. The re¬
marks, therefore, now made on the dramatic
art, may also be applied to the sciences which
rest on observation.”5—(De VEsprit, His. IV.
Chap. I.)
With this last extension of the Law of Con¬
tinuity, as well as with that of Bonnet, a care¬
less reader is the more apt to he dazzled, as there
is a large mixture in both of unquestionable
truth. The mistake of the ingenious writers
lay in pushing to extreme cases a doctrine, which,
1 Lemons d'Anatomic Comparte.
2 While Bonnet was thus employing his ingenuity in generalising, still farther than his predecessors had done, the law
of continuity, one of the most distinguished of his fellow citizens, with whom he appears to have been connected in the
closest and most confidential friendship (the very ingenious M. Le Sage), was led, in the course ol his researches concerning^
the physical cause of gravitation, to deny the existence of the law, even in the descent of heavy bodies. “ The action ot
gravity (according to him) is not continuous.” In other words, “ each of its impressions is finite; and the interval or time
which separates it from the following impression is of a finite duration.” Of this proposition he offers a proof, which he
considers as demonstrative; and thence deduces the following very paradoxical corollary, That “ Projectiles do not move
in curvilinear paths, but in rectilinear polygons.” *—“ C’est ainsi (he adds) qu’un prds, qui yu de pres, se trouve couvert
de parties vertes reellement separees, offre cependant aux personnes qui le regardent de loin, la sensation dune verdure
continue : Et qu’un corps poli, auquel le microscope decouvre mille solutions de continuite, paroit a I’oeil nu, posseder une
continuity parfaite.” . ' ,
“ Ge'ndralement, le simple bons sens, qui veut, qu’on suspende son jugement sur ce qu’on ignore, et que 1 on ne tranche
pas hardiment sur la non-existence de ce qui echappe a nos sens, auroit du empecher des gens qui s’appelloient phxlosophes
de decider si dogmatiquement, la continuite reelle, de ce qui avoit une continuity apparente ; et la non-existenar des. m-
tervalles qu’ils n’apercevoient pas.”—fEssai de Chymie Mecanique. Couronne en 1758, par 1’Academic de Rouen : Impnme
a Geneve, 1761. pp. 94. 95. 96.) . , , i c r r i
3 It may, perhaps, be alleged, that the above allusion to the Law of Continuity was introduced merely for the sake or il¬
lustration, and that the author did not mean his words to be strictly interpreted; but this remark will not be made by those
who are acquainted with the philosophy of Helvetius. . ,
' Let me add, that, in selecting Corneille as the only exemplification of this theory, Helvetius has been singularly unlor-
tunate. It would have been difficult to have named any other modern poet, in whose works, when compared with those ol
his immediate predecessors, the Law of Continuity has been more remarkably violated. “Corneille (says a most judicious
French critic) est, pour ainsi dire, de notre terns; mais ses contemporains n’en sont pas. Le Cid, les Horaces, Cinna, o-
lieucte, forment le commencement de cette chaine brillante qui reunit notre litterature actuelle de celle du regne e ic e-
lieu et de la minority de Louis XIV.; mais autour de ces points lumineux regne encore une nuit profonde ; leur eclat les
rapproche en apparence de nos yeux; le reste, repousse dans Pobscurity, semble bien loin de nous. Pour nous ornei w
est moderne, et Rotrou ancien,” &c. (For detailed illustrations and proofs of these positions, see a slight but masterly His¬
torical sketch of the French Theatre, by M. Suard.)
* “ Ullas vero curvas in rerum natura esse negavere multi. Nominabo tantum, qui nunc occurrunt. Lubmurn, Bassonem.
Regium, Bonartem, et quern parum abest, quin addam Hobbesium."—(Leibnitz, Op. Tom. II. p. 47.)
136
PRELIMINARY DISSERTATIONS.
when kept within certain limits, is not only so¬
lid but important; a mode of reasoning', which,
although it may be always safely followed out in
pure Mathematics (where the principles on
which we proceed are mere definitions), is a
never-failing source of error in all the other
sciences; and which, when practically applied
to the concerns of life, may be regarded as an
infallible symptom of an understanding better
fitted for the subtle contentions of the schools,
than for those average estimates of what is ex¬
pedient and practicable in the conduct of affairs,
which form the chief elements of political saga¬
city and of moral wisdom.1
If on these two celebrated principles of Leib¬
nitz, I have enlarged at greater length than may
appear to some of my readers to be necessary,
I must remind them, ls£, Of the illustration
they afford of what Locke has so forcibly urged
with respect to the danger of adopting, upon the
faith of reasonings a priori, metaphysical conclu¬
sions concerning the laws by which the universe
is governed: 2dly, Of the proof they exhibit of
the strong bias of the human mind, even in the
present advanced stage of experimental know¬
ledge, to grasp at general maxims, without a
careful examination of the grounds on which
they rest; and of that less frequent, but not less
unfortunate bias, which has led some of our
most eminent mathematicians to transfer to
sciences, resting ultimately on an appeal to facts,
those habits of thinking which have been formed
amidst the hypothetical abstractions of pure
geometry : Lastly, Of the light they throw on
the mighty influence which the name and autho¬
rity of Leibnitz have, for more than a century
past, exercised over the strongest and acutest
understandings in the most enlightened coun¬
tries of Europe.
It would be improper to close these reflections
on the philosophical speculations of Leibnitz,
without taking some notice of his very ingenious
and original thoughts on the etymological study
of languages, considered as a guide to our con¬
clusions concerning the origin and migrations of
different tribes of our species. These thoughts
were published in 1710, in the Memoirs of the
Berlin Academy; and form the first article of
the first volume of that justly celebrated collec¬
tion. I do not recollect any author of an ear¬
lier date, who seems to have been completely
aware of the important consequences to which
the prosecution of this inquiry is likely to lead ;
nor, indeed, was much progress made in it by
any of Leibnitz’s successors, till towards the end
of the last century; when it became a favourite
object of pursuit to some very learned and inge¬
nious men, both in France, Germany, and Eng¬
land. Now, however, when our knowledge of
the globe, and of its inhabitants, is so wonder¬
fully enlarged by commerce, and by conquest;
and when so great advances have been made in
the acquisition of languages, the names of which,
till very lately, were unheard of in this quarter
of the world;—there is every reason to hope for
a series of farther discoveries, strengthening pro¬
gressively, by the multiplication of their mutual
points of contact, the common evidence of their
joint results; and tending more and more to
dissipate the darkness in which the primeval
history of our race is involved. It is a field, of
which only detached corners have hitherto been
explored; and in which, it may be confidently
presumed, that unthought of treasures still lie
hid, to reward sooner or later the researches of
our posterity.2
My present subject does not lead me to speak
of the mathematical and physical researches,
1 Locke has fallen into a train of thought very similar to that of Bonnet, concerning the Scale of Beings; but has ex¬
pressed himself with far greater caution ;—stating it modestly as an inference deduced from an induction of particulars, not
as the result of any abstract or metaphysical principle.—(See Locke’s Works, Vol. III. p. 101.) In one instance, indeed, he
avails himself of an allusion, which, at first sight, may appear to favour the extension of the mathematical Law of Continuity
to the works of creation ; but it is evident, from the context, that he meant this allusion merely as a popular illustration of
a fact in Natural History ; not as the rigorous enunciation of a theorem applicable alike to all truths, mathematical, physi¬
cal, and moral. “ It is a hard matter to say where sensible and rational begin, and where insensible and irrational end ;
and who is there quick-sighted enough to determine precisely, which is the lowest species of living things, and which is the
first of those who have no life ? Things, as far as we can observe, lessen and augment, as the quantity does in a regular
cone, where, though there be a manifest odds betwixt the bigness of the diameter at a remote distance, yet the difference
between the upper and under, where they touch one another, is hardly discernible.” {Ibid.)
See some Reflections on this speculation of Locke’s in the Spectator, No. 5IP.
a bee Note F F.
DISSERTATION FIRST.
wltichhave associated so closely tlie name of Leib¬
nitz with that of Newton, in the history of modern
science; of the inexhaustible treasures of his
erudition, both classical and scholastic ; of his
vast and manifold contributions towards the
elucidation of German antiquities and of Roman
jurisprudence ; or of those theological controver¬
sies, in which, while he combated with one hand
the enemies of revelation, he defended, with the
other, the orthodoxy of his own dogmas against
the profoundest and most learned divines of Eu¬
rope. Nor would I have digressed so far as to
allude here to these particulars, were it not for
the unparalleled example they display, of what
a vigorous and versatile genius, seconded by
habits of persevering industry, may accomplish,
within the short span of human life. Even the
relaxations with which he was accustomed to fill
up his moments of leisure, partook of the general
character of his more serious engagements. By
early and long habit, he had acquired a singular
facility in the composition of Latin verses; and
he seems to have delighted in loading his muse
with new fetters of his own contrivance, in ad¬
dition to those imposed by the laws of classical
prosody.1 The number, besides, of his literary
correspondents was immense ; including all that
was most illustrious in Europe : and the rich
materials everywhere scattered over his letters
are sufficient of themselves to show, that his
amusements consisted rather in a change of ob¬
jects, than in a suspension of his mental activi¬
ty. Yet while we admire these stupendous mo¬
numents of his intellectual'energy, we must not
forget (if I may borrow the language of Gibbon)
that “ even the powers of Leibnitz were dissipat¬
ed by the multiplicity of his pursuits. He at¬
tempted more than he could finish; he designed
more than he could execute; his imagination
was too easily satisfied with a bold and rapid
glance on the subject which he was impatient to
leave ; and he may be compared to those heroes
L37
whose empire has been lost in the ambition of
universal conquest.”*
From some expressions which Leibnitz has
occasionally dropped, I think it probable, that
he himself became sensible, as he advanced in
life, that his time might have been more pro¬
fitably employed, had his studies been more con¬
fined in their aim. “ If the whole earth (he has
observed on one occasion) had continued to be
of one language and of one speech, human life
might be considered as extended beyond its pre¬
sent term, by the addition of all that part of it
which is devoted to the acquisition of dead and
foreign tongues. Many other branches of know¬
ledge, too, may, in this respect, be classed with
the languages; such as Positive Laws, Cere¬
monies, the Styles of Courts, and a great pro¬
portion of what is called critical erudition. The
utility of all these arises merely from opinion;
nor is there to be^found, in the innumerable
volumes that have been written to illustrate
them, a hundredth part, which contains any¬
thing subservient to the happiness or improve¬
ment of mankind.”
The most instructive lesson, however, to be
drawn from the history of Leibnitz, is the in¬
competency of the most splendid gifts of the un¬
derstanding, to advance essentially the interests
either of Metaphysical or of Ethical Science, un¬
less accompanied with that rare devotion to truth,
which maybe regarded, if not as the basis, at least
as one of the most indispensable elements, of mo¬
ral genius. The chief attraction to the study
of philosophy, in his mind, seems to have been
(what many French critics have considered as a
chief source of the charms of the imitative arts)
the pride of conquering difficulties: a feature of
his character which he had probably in his own
eye, when he remarked (not without some de¬
gree of conscious vanity), as a peculiarity in the
turn or cast of his intellect, that to him “ all
difficult things were easy, and all easy things
1 A remarkable instance of this is mentioned by himself in one of his letters. “ Annos natus tredecim una die trecentos
versus hexametros effudi, sine elisione omnes, quod hoc fieri facile posse forte affirmassem.” (Leib. Op. Tom. V. p. 304.)
He also amused himself occasionally with writing verses in German and in French.
s May I presume to remark farther, that the native powers of Leibnitz’s mind, astonishing and preternatural as they
certainly were, seem sometimes oppressed and overlaid under the weight of his still more astonishing erudition ? The in¬
fluence of his scholastic reading is more peculiarly apparent in warping his judgment, and clouding his reason, on all ques¬
tions connected with Metaphysical Theology.
DISS. I. PART II. s
138
PRELIMINARY DISSERTATIONS.
difficult.”1 Hence the disregard manifested in
his writings to the simple and obvious conclu¬
sions of experience and common sense; and the
perpetual effort to unriddle mysteries over which
an impenetrable veil is drawn. “ Scilicet su¬
blime et erectum ingenium, pulehritudinem ac
speciem excelsse magnseque gloria? vehementius
quam caute appetebat.” It is to he regretted,
that the sequel of this fine eulogy does not equal¬
ly apply to him. “ Mox mitigavit ratio et eetas;
retinuitque, quod est difficillimum, et in sapientia
modum.” 2 How happily does this last expression
characterise the temperate wisdom of Locke,
when contrasted with that towering, but impo¬
tent ambition, which, in the Theories of Opti¬
mism and of Pre-established Harmony, seemed
to realize the fabled revolt of the giants against
the sovereignty of the gods !
After all, a similarity may be traced between
these two great men in one intellectual weakness
common to both; a facility^n the admission of
facts, stamped sufficiently (as we should now
think) by their own intrinsic evidence, with the
marks of incredibility. The observation has
been often made with respect to Locke; hut it
would be difficult to find in Locke’s writings,
any thing so absurd as an account gravely trans¬
mitted by Leibnitz to the Abbe de St Pierre,
and by him communicated to the Royal Acade¬
my of Sciences at Paris, of a dog who spoke.5
No person liberally educated could, I believe,
be found at present in any Protestant country of
Christendom, capable of such credulity. By
what causes so extraordinary a revolution in the
minds of men has been effected, within the short
space of a hundred years, I must not here stop to
inquire. Much, I apprehend, must be ascribed
to our enlarged knowledge of nature, and more
particularly to those scientific voyages and tra¬
vels which have annihilated so many of the
prodigies which exercised the wonder and sub¬
dued the reason of our ancestors. But, in what¬
ever manner the revolution is to he explained,
there can be no doubt that this growing dispo¬
sition to weigh scrupulously the probability of
alleged facts against the faith due to the testi¬
monies brought to attest them, and, even in
some cases, against the apparent evidence of our
own senses, enters largely and essentially into
the composition of that philosophical spirit or
temper, which so strongly distinguishes the
eighteenth century from all those which preced¬
ed it.4 It is no small consolation to reflect,
that some important maxims of good sense have
been thus familiarised to the most ordinary un¬
derstandings, which, at so very recent a period,
failed in producing their due effect on two of
the most powerful minds in Europe.
On reviewing the foregoing paragraphs, I am
almost tempted to retract part of what I have
written, when I reflect on the benefits which the
world has derived even from the errors of Leib¬
nitz. It has been well and justly said, that
“ every desideratum is an imperfect discovery
to which it may be added, that every new pro¬
blem which is started, and still more every at¬
tempt, however abortive, towards its solution,
strikes out a new path, which must sooner or
later lead to the truth. If the problem be sol-
vible, a solution will in due time be obtained :
if insolvible, it will soon be abandoned as hope¬
less by general consent; and the legitimate field
of scientific research will become more fertile,
in proportion as a more accurate survey of its
boundaries adapts it better to the limited re¬
sources of the cultivators.
In this point of view, what individual in mo¬
dern times can be compared to Leibnitz ! To
how many of those researches, which still use¬
fully employ the talents and industry of the
learned, did he not point out and open the
way ! From how many more did he not warn
the wise to withhold their curiosity, by his hold
and fruitless attempts to burst the barriers of
the invisible world!
The best eloge of Leibnitz is furnished by the
literary history of the eighteenth century ;—a
history which, whoever takes the pains to com¬
pare with his works, and with his epistolary
correspondence, will find reason to doubt
1 “ Sentio paucos esse mei characteris, et omnia faciiia mihi difficilia, omnia contra difficilia mihi facilia esse.”—Leib.
Oja. Tom. VI. p. 302.
* Tacitus, Agric.
See Note G G.
* See Note H H.
DISSERTATION FIRST.
139
whether, at the singular era when he appeared,
he could have more accelerated the advancement
of knowledge hy the concentration of his studies,
than he has actually done by the universality
of his aims; and whether he does not afford one
of the few instances to which the words of the
poet may literally be applied :
“ Si non errasset, fecerat ille minus.”
SECTION III.
Of the Metaphysical Speculations of Newton and Clarke. Digression with respect to the System of
Spinoza.—Collins and Jonathan Edwards.—Anxiety of both to reconcile the Scheme of Necessity
with Man's Moral Agency.—Departure of some later Necessitarians from their views A
The foregoing review of the philosophical
writings of Locke and of Leibnitz naturally
leads our attention, in the next place, to those of
our illustrious countrymen Newton and Clarke;
the former of whom has exhibited, in his Prin-
cipia and Optics, the most perfect exemplifica¬
tions which have yet appeared, of the cautious
logic recommended by Bacon and Locke; while
the other, in defending against the assaults of
Leibnitz the metaphysical principles on which
the Newtonian philosophy proceeds, has been
led, at the same time, to vindicate the authority
of various other truths, of still higher impor¬
tance, and more general interest.
The chief subjects of dispute between Leibnitz
and Clarke, so far as the principles of the New¬
tonian philosophy are concerned, have been long
ago settled, to the entire satisfaction of the learn¬
ed world. The monads, and the plenum, and the
pre-established harmony of Leibnitz, already rank,
in the public estimation, with the vortices of
Descartes, and the plastic nature of Cudworth;
while the theory of gravitation prevails every¬
where over all opposition; and (as Mr Smith
remarks) “ has advanced to the acquisition of
the most universal empire that was ever esta¬
blished in philosophy.” On these points, there¬
fore, I have only to refer my readers to the col¬
lection published by Dr Clarke, in 1717, of
the controversial papers which passed between
him and Leibnitz during the two preceding
years;—a correspondence equally curious and
instructive; and which, it is to be lamented,
that the death of Leibnitz in 1716 prevented
from being longer continued.5
Although Newton does not appear to have de-
1 See Note 11.
2 In conformity to the plan announced in the preface to this Dissertation, I confine myself to those authors whose opinions
have had a marked and general influence on the subsequent history of philosophy; passing over a multitude of other names
well worthy to be recorded in the annals of metaphysical science. Among these, I shall only mention the name of Boyle,
to whom the world is indebted, beside some very acute remarks and many fine illustrations of his own upon metaphysical
questions of the highest moment, for the philosophical arguments in defence of religion, which have added so much lustre
to the names of Derham and Bentley ; and, far above both, to that of Clarke.* The remarks and illustrations, which I here
refer to, are to be found in his Inquiry into the Vulgar Notion of Nature, and in his Essay, inquiring whether, and how, a Natu¬
ralist should consider Final Causes. Both of these tracts display powers which might have placed their author on a level with
Descartes and Locke, had not his taste and inclination determined him more strongly to other pursuits. I am inclined to
think, that neither of them is so well known as were to be wished. I do not even recollect to have seen it anywhere no¬
ticed, that some of the most striking and beautiful instances of design in the order of the material world, which occur in the
Sermons preached at Boyle’s Lecture, are borrowed from the works of the founder, -f-
Notwichstanoing, however, these great merits, he has written too little on such abstract subjects to entitle him to a place
among English metaphysicians; nor has he, like Newton, started any leading thoughts which have since given a new direc¬
tion to the studies of metaphysical inquirers. From the slight specimens he has left, there is reason to conclude, that his
mind was still more happily turned than that of Newton, for the prosecution of that branch of science to which their con¬
temporary Locke was then beginning to invite the attention of the public.
3 From a letter of Leibnitz to M. Remond de Montmort, it appears that he considered Newton, and not Clarke, as his
* To the English reader it is unnecessary to observe, that I allude to the Sermons preached at the Lecture founded by
the Honourable Robert Boyle.
j' 1 hose instances, more especially, which are drawn from the anatomical structure of animals, and the adaptation of their
perceptive organs to the habits of life for which they are destined.
140
PRELIMINARY DISSERTATIONS.
voted much of his time to Metaphysical re¬
searches, yet the general spirit of his physical
investigations has had a great, though indiiect,
influence on the metaphysical studies of his suc¬
cessors. It is justly and profoundly remarked
hy Mr Hume, that “ while Newton seemed to
draw off the veil from some of the mysteries of
nature, he showed, at the same time, the impel-
fections of the mechanical philosophy, and there¬
by restored her ultimate secrets to that obscurity
in which they ever did, and ever will remain.
In this way, his discoveries have co-operated
powerfully with the reasonings of Locke in pro¬
ducing a general conviction of the inadequacy of
our faculties to unriddle those sublime enigmas
on which Descartes, Malebranche, and Leib¬
nitz, had so recently wasted their strength, and
which, in the ancient world, were regarded as
the only fit objects of philosophical curiosity.
It is chiefly too since the time of Newton, that
the ontology and pneumatology of the dark ages
have been abandoned for inquiries resting on the
solid basis of experience and analogy; and that
philosophers have felt themselves emboldened
by his astonishing discoveries concerning the
more distant parts of the material universe, to
argue from the known to the unknown parts of
the moral world. So completely has the pre¬
diction been verified which he himself hazarded,
in the form of a query, at the end of his Optics,
that “ if natural philosophy should continue to
be improved in its various branches, the hounds
of moral philosophy would he enlarged also.”
How far the peculiar cast of Newton’s genius
qualified him for prosecuting successfully the
study of Mind, he has not afforded us sufficient
data for judging; but such was the admiration
with which his transcendent powers as a Mathe¬
matician and Natural Philosopher were univer¬
sally regarded, that the slightest of his hints on
other subjects have been eagerly seized upon as
indisputable axioms, though sometimes with
little other evidence in their favour hut the sup¬
posed sanction of his authority.1 The part of
his works, however, which chiefly led me to con¬
nect his name with that of Clarke, is a passage
in the Scholium annexed to his Principal,2 which
may he considered as the germ of the celebrated
real antagonist in this controversy. “ M. Clarke, ou plut6t M. Newton, dont M. Clarke soutient les dogmes, est en dispute
avec moi sur la philosophie”_(LEiB. Op. Tom. Y. p. 33.) From another letter to the same correspondent we learn that
Leibnitz aimed at nothing less than the complete overthrow of the Newtonian philosophy; and that it was chieHy to his
trrand nrincinle of the sufficient reason that he trusted for the accomplishment of this object. Jai reduit 1 etat de notre
disnute a ce grand axiome, que Hen n'existe ou n'arrive sans qu'il y ait une raison suffisante, pourquoi il en est plutot ainst qiiau-
trement. S’il continue a me le nier, oil en sera sa sincerite ? S’il me 1’accorde, adieu le yuide, les atonies, rfyowte la philoso-
vhie de M Newton.”—(Hid.) See also a letter from Leibnitz to M des Maizeaux m the same volume of Ins works p. 39.
‘ Witness Hartley’s Physiological Theory of the Mind, founded on a query in Newton’s Optics; and a long list of theories
in medicine, grafted on a hint thrown out in the same query, in the form of a modest conjecture. . , . . „ .
2 This Scholium, it is to be observed, first appeared at the end of the second edition of the Pnncipta, printed at Cambridge
in 1713. The'former edition, published at London in 1687, has no Scholium annexed to it. From a passage, however, in a
letter of Newton’s to Dr Bentley (dated 1692), it seems probable, that as far back, at least, as that period, he had tnoughts
of attempting a proof a priori of the existence of God. After some new illustrations, drawn from his own discoveries, of the
common argument from final causes, he thus concludes : “ There is yet another argument for a Deity, which I take to be a
very strong one; but, till the principles on which it is grounded are better received, I think it more advisable to let it
sleep.” (l'our Letters from Sir I. Newton to Dr Bentley, p. 11. London, Dodsley, 1756.)
It appears from this passage, that Newton had no intention, like his predecessor Ilescartes, to supersede, by any new ar¬
gument of his own for the existence of God, the common one drawn from the consideration of final causes;^, therefore,
nothing could be more uncandid than the following sarcasm pointed by Pope at the laudable attempts of his two country¬
men to add to the evidence of this conclusion, by deducing it from other principles:
“ Let others creep by timid steps and slow,
On plain experience lay foundations low,
By common sense to common knowledge bred.
And last to Nature’s cause thro’ Nature led-'
We nobly take the high priori-road,
And reason downwards till we doubt of God.”
That Pope had Clarke in his eye when he wrote these lines, will not be doubted by those who recollect the \anous other
occasions in which he has stepped out of his way, to vent an impotent spleen against this excellent person.
“ Let Clarke live half his life the poor’s support,
But let him live the other half at court.”
And again :
“ Even in an ornament its place remark;
Nor in a hermitage set Dr Clarke
in which last couplet there is a manifest allusion to the bust of Clarke, placed in a hermitage by Queen Caroline, together
with those of Newton, Boyle, Locke, and Wollaston. See some fine verses on these busts in a poem called the Grotto, by
Matthew Green.
DISSERTATION FIRST.
141
argument a priori for the existence of God, which
is commonly, though, I apprehend, not justly,
regarded as the most important of all Clarke’s
contributions to Metaphysical Philosophy. I
shall quote the passage in Newton’s own words,
to the oracular conciseness of which no English
version can do j ustice.
44 iEternus est et infinitus, omnipotens et om-
nisciens; id est, durat ah aeterno in aeternum, et
adest ah infinito in infinitum Non est
aeternitas et infinitas, sed aeternus et infinitus ;
non est duratio et spatium, sed durat et adest.
Durat semper et adest ubique, et existendo sem¬
per et ubique durationem et spatium constituit.”1
Proceeding on these principles, Dr Clarke argued,
that, as immensity and eternity (which force
themselves irresistibly on our belief as necessary
existences, or, in other words, as existences of
which the annihilation is impossible) are not
substances^ but attributes^ the immense and eter¬
nal Being, whose attributes they are, must exist
of necessity also. The existence of God, there¬
fore, according to Clarke, is a truth that follows
with demonstrative evidence from those concep¬
tions of space and time which are inseparable
from the human mind 44 These (says Dr
Reid) are the speculations of men of superior
genius; but whether they be as solid as they are
sublime, or whether they be the wanderings of
imagination in a region beyond the limits of the
human understanding, I am at a loss to deter¬
mine.” After this candid acknowledgment from
Dr Reid, I need not he ashamed to confess my
own doubts and difficulties on the same ques¬
tion.2
But although the argument, as stated by
Clarke, does not carry complete satisfaction to
my mind, I think it must be granted that there
is something peculiarly wonderful and over¬
whelming in those conceptions of immensity and
eternity, which it is not less impossible to banish
from our thoughts, than the consciousness of our
own existence. Nay, further, I think that these
conceptions are very intimately connected with
the fundamental principles of Natural Religion.
For when once we have established, from the
evidences of design everywhere manifested
around us, the existence of an intelligent and
powerful cause, we are unavoidably led to apply
to this cause our conceptions of immensity and
eternity, and to conceive Him as filling the infi¬
nite extent of both with his presence and with
his power. Hence we associate with the idea of
God those awful impressions which are naturally
produced by the idea of infinite space, and per¬
haps still more by the idea of endless duration.
Nor is this all. It is from the immensity of
space that the notion of infinity is originally de¬
rived ; and it is hence that we transfer the ex¬
pression, by a sort of metaphor, to other subjects.
When we speak, therefore, of infinite power, wis¬
dom, and goodness, our notions, if not wholly
borrowed from space, are at least greatly aided
by this analogy; so that the conceptions of Im¬
mensity and Eternity, if they do not of them¬
selves demonstrate the existence of God, yet ne¬
cessarily enter into the ideas we form of his na¬
ture and attributes.
To these various considerations it may be
added that the notion of necessary existence which
we derive from the contemplation of Space and
of Time, renders the same notion, when applied
to the Supreme Being, much more easy to be
apprehended than it would otherwise be.
It is not, therefore, surprising, that Newton
and Clarke should have fallen into that train of
thought which encouraged them to attempt a
demonstration of the being of God from our
conceptions of Immensity and Eternity; and
still less is it to be wondered at, that, in pursu¬
ing this lofty argument, they should have soar¬
ed into regions where they were lost in the
clouds.
I have said above, that Clarke’s demonstra¬
tion seems to have been suggested to him by a
passage in Newton’s Scholium. It is, however,
1 Thus translated by Dr Clarke: “ God is eternal and infinite, omnipotent and omniscient; that is, he endures from
everlasting to everlasting, and is present from infinity to infinity. He is not eternity or infinity, but eternal and infinite,
lie is not duration or space, but he endures and is present. He endures always, and is present everywhere, and by exist¬
ing always and everywhere, constitutes duration and space.”—(See Clarke’s Fourth Reply to Leibnitz.)
2 An argument substantially the same with this for the existence of God, is hinted at very distinctly by Cudworth,
Intellect. System, Chap. Y. sect. 3. 4. Also by Dr Henry More, Enchir. Metaph. Cap. 8. sect. 8. See Mosheim’s TransU of
Cudworth, Tom. II. p. 356.
142
PRELIMINARY DISSERTATIONS.
more than probable that be bad himself struck
into a path very nearly approaching to it, at a
much earlier period of his life. The following
anecdote of his childhood, related, upon his own
authority, by his learned and authentic, though,
in many respects, weak and visionary biogra-
gher (Whiston), exhibits an interesting example
of an anomalous development of the powers of
reflection and abstraction, at an age when, in
ordinary cases, the attention is wholly engross¬
ed with sensible objects. Such an inversion of
the common process of nature in unfolding our
different faculties, is perhaps one of the rarest
phenomena in the intellectual world; and,
wherever it occurs, may be regarded as strongly
symptomatic of something peculiar and decided
in the philosophical character of the individual.
“ One of his parents,” says Whiston, “ ask¬
ed him when he was very young, Whether God
could do every thing ? He answered, Yes ! He
was asked again, Whether God could tell a lie ?
He answered, No ! And he understood the ques¬
tion to suppose, that this was the only thing
that God could not do; nor durst he say, so
young was he then, that he thought there was
any thing else which God could not do; while
yet, well he remembered, that he had, even then,
a clear conviction in his own mind, that there was
one thing which God could not do ;—that he could
not annihilate that space which was in the room
where they were.”x
With this early and deep impression on his
mind, it is easy to conceive how Newton’s
Scholium should have encouraged him to resume
the musings of his boyish days, concerning the
necessary existence of space; and to trace, as
far as he could, its connection with the prin¬
ciples of Natural Theology. But the above anec¬
dote affords a proof how strongly his habits of
thought had long before predisposed him for the
prosecution of a metaphysical idea, precisely the
same with that on which this Scholium proceeds.
It would be superfluous to dwell longer on
the history of these speculations, which, what¬
ever value they may possess in the opinion of
persons accustomed to deep and abstract rea¬
soning, are certainly not well adapted to ordi¬
nary or to uncultivated understandings. This
consideration furnishes, of itself, no slight pre¬
sumption, that they were not intended to be the
media by which the bulk of mankind were to be
led to the knowledge of truths so essential to
human happiness; and, accordingly, it was on
this very ground, that Bishop Butler, and Dr
Francis Hutcheson, were induced to strike into
a different and more popular path for establish-
1 The question concerning the necessary existence of Space and of Time formed one of the principal subjects of discus¬
sion between Clarke and Leibnitz. According to the former, space and time are, both of them, infinite, immutable, and
indestructible. According to his antagonist, “ space is nothing but the order of things co-existing,” and “ time nothing
but the order of things successive !” The notion of real absolute Space, in particular, he pronounces to be a mere chimera
and superficial imagination ; classing it with those prejudices which Bacon called idola tribus—(See his 4th Paper, § 14.)
It has always appeared to me a thing quite inexplicable, that the great majority of philosophers, both in Germany and
in France, have, on the above question, decided in favour of Leibnitz. Even D’Alembert himself, who, on most metaphy¬
sical points, reasons so justly and so profoundly, has, in this instance, been carried^along by the prevailing opinion (or, per¬
haps, it would be more correct to say, by the fashionable phraseology) among his countrymen. “ Y auroit-il un espace,
s’il n’y avoit point de corps, et une duree s’il n’y avoit rien ? Ces questions viennent, ce me semble, de ce qu’on suppose au
temps et a 1’espace plus de re'alitd qu’ils n’en ont Les enfants, qui disent que le vuide n’est rien, ont raison parce
qu’ils s’en tiennent au simples notions du sens commun:* et les philosophes qui veulent realiser le vuide se perdent
dans leurs speculation's : le vuide a ete enfante par les abstractions, et voila I’abus d’une methode si utile a bien des egards.
S'il n'y avoit point de corps et de succession, Vespace ct le temps seroient possibles, mais its n'existeroient pas."—(Melanges, &c.
T. V. § xvi.) Bailly, a writer by no means partial to D’Alembert, quotes, with entire approbation, the foregoing observa¬
tions; subjoining to them, in the following terms, his own judgment on the merits of this branch of the controversy be¬
tween Clarke and Leibnitz. “ La notion du temps et de 1’espace, est un des points sur lesquels Leibnitz a combattu cen¬
tre Clarke ; mais il nous semble que 1’Anglois n’a rien oppose de satisfaisant aux raisons de Leibnitz.”—(Eloge de Leibnitz. )
As for the point here in dispute, I must own, that it does not seem to me a fit subject for argument; inasmuch as I can¬
not even form a conception of the proposition contended for by Leibnitz. The light in which the question struck Clarke
in his childhood, is the same in which I am still disposed to view it; or rather, I should say, is the light in which I must
ever view it, while the frame of my understanding continues unaltered. Of what data is human reason possessed, from
which it is entitled to argue in opposition to truths, the contrary of which it is impossible not only to prove, but to express
in terms comprehensible by our faculties ?
For some remarks on the scholastic controversies concerning space and time, see the First Part of this Dissertation, Note I.
See also Locke’s Essay, Book ii. Chap. 13. §§ 16, 17, 18.
* I quote the sequel of this passage on the authority of Bailly (see his Eloyc on Leibnitz'), for it is not to be found in the
copy of the Melanges before me printed at Amsterdam in 1767.
DISSERTATION FIRST.
143
mg the fundamental principles of religion and
morality. Both of these writers appear to have
communicated, in very early youth, their doubts
and objections to Dr Clarke; and to have had,
even then, a glimpse of those inquiries by which
they were afterwards to give so new and so for¬
tunate a direction to the ethical studies of their
countrymen. It is sufficient here to remark
this circumstance as an important step in the
progress of Moral Philosophy. The farther il¬
lustration of it properly belongs to another part
of this discourse.
The chief glory of Clarke, as a metaphysical
author, is due to the boldness and ability with
which he placed himself in the breach against
the Necessitarians and Fatalists of his times.
With a mind far inferior to that of Locke, in
comprehensiveness, in originality, and in ferti¬
lity of invention, he was nevertheless the more
wary and skilful disputant of the two, possess¬
ing, in a singular degree, that reach of thought
in grasping remote consequences, which effec¬
tually saved him from those rash concessions
into which Locke was frequently betrayed by
the greater warmth of his temperament, and vi¬
vacity of his fancy. This logical foresight (the
natural result of his habits of mathematical
study) rendered him peculiarly fit to contend
with adversaries, eager and qualified to take ad¬
vantage of every vulnerable point in his doc¬
trines; but it gave, at the same time, to his
style a tameness, and monotony, and want of
colouring, which never appear in the easy and
spirited, though often unfinished and unequal,
sketches of Locke. Voltaire has somewhere
said of him, that he was a mere reasoning ma¬
chine (un moulin a raisonnementJ, and the ex¬
pression (though doubtless much too unquali¬
fied) possesses a merit, in point of just discri¬
mination, of which Voltaire was probably not
fully aware.1
I have already taken notice of Clarke’s de¬
fence of moral liberty in opposition to Leibnitz ;
but soon after this controversy was brought to a
1 In the extent of his learning, the correctness of his taste, and the depth of his scientific acquirements, Clarke possess¬
ed indisputable advantages over Locke; with which advantages he combined another not less important, the systematical
steadiness with which his easy fortune and unbroken leisure enabled him to pursue his favourite speculations through the
whole course of his life.
On the subject of Free-will, Locke is more indistinct, undecided, and inconsistent, than might have been expected from
his powerful mind, when directed to so important a question. This was probably owing to his own strong feelings in fa¬
vour of man’s moral liberty, struggling with the deep impression left on his philosophical creed by the writings of
Hobbes, and with his deference for the talents of his own intimate friend, Anthony Collins.® That Locke conceived him¬
self to be an advocate for free-will, appears indisputably from many expressions in his Chapter on Power; and yet, in that
very chapter, he has made various concessions to his adversaries, in which he seems to yield all that was contended for by
Hobbes and Collins : And, accordingly, he is ranked, with some appearance of truth, by Priestley, with those who, while
they opposed verbally the scheme of necessity, have adopted it substantially, without being aware of their mistake.
In one of Locke’s letters to Mr Molyneux, he has stated, in the strongest possible terms, his conviction of man’s free
agency ; resting this conviction entirely on our indisputable consciousness of the fact. This declaration of Locke I consi¬
der as well worthy of attention in the argument about Free Will; for, although in questions of pure speculation, the au¬
thority of great names is entitled to no weight, excepting in so far as it is supported by solid reasonings, the case is other¬
wise with, facts relating to the phenomena of the human mind. The patient attention with which Mr Locke had studied
these very nice phenomena during the course of a long life, gives to the results of his metaplrysical experience a value of
the same sort, but much greater in degree, with that which we attach to a delicate experiment in chemistry, when vouched
by a Black or a Davy. The ultimate appeal, after all, must be made by every person to his own consciousness ; but
when we have the experience of Locke on the one hand, and that of Priestley and Belsham on the other, the contrast is
surely sufficient to induce every cautious inquirer to re-examine his feelings before he allows himself to listen to the
statements of the latter in preference to that of the former.
For the information of some of my readers, it may be proper to mention that it has of late become fashionable among a
certain class of metaphysicians, boldly to assert, that the evidence of their consciousness is decidedly in favour of the scheme
of necessity.
But to return to Mr Locke. The only consideration on this subject which seems to have staggered him, was the difficul¬
ty of reconciling this opinion with the prescience of God. As to this theological difficulty, I have nothing to say at present.
The only question which I consider as of any consequence, is the matter of fact; and, on this point, nothing can be more
explicit and satisfactory than the words of Locke. In examining these, the attentive reader will be satisfied, that Locke’s
declaration is not (as Priestley asserts) in favour of the Liberty of Spontaneity, but in favour of the Liberty of Indifference ;
for as to the former, there seems to be no difficulty in reconciling it with the prescience of God. “ I own (says Mr Locke)
freely to you the weakness of my understanding, that though it be unquestionable that there is omnipotence and omnisci¬
ence in God our Maker, and though I cannot have a clearer perception of anything than that I am free; yet I cannot make free¬
dom in man consistent with omnipotence and omniscience in God, though I am as fully persuaded of both as of any truth
I most firmly assent to ; and therefore I have long since given off the consideration of that question ; resolving all into
this short conclusion, that, if it be possible for God to make a free agent, then man is free, though J see not the way of it."
See Note K K.
144
PRELIMINARY DISSERTATIONS.
conclusion by the death of his antagonist, he
had to resume the same argument, in reply to
his countryman, Anthony Collins ; who, follow¬
ing the footsteps of Hobbes, with logical talents
not inferior to those of his master, and with a
weight of personal character in his favour, to
which his master had no pretensions,1 gave to
the cause which he so warmly espoused, a de¬
gree of credit among sober and serious inquir¬
ers, which it had never before possessed in Eng¬
land. I have reserved, therefore, for this place,
the few general reflections which I have to offer
on this endless subject of controversy. In stat¬
ing these, I shall be the less anxious to con¬
dense my thoughts, as I do not mean to return
to the discussion in the sequel of this historical
sketch. Indeed, I do not know of anything
that has been advanced by later writers, in
support of the scheme of necessity, of which
the fferm is not to be found in the inquiry of
Collins.
In order to enter completely into the motives
which induced Clarke to take so zealous and so
prominent a part in the dispute about Free
Will, it is necessary to look back to the sys¬
tem of Spinoza; an author, with whose pecu¬
liar opinions I have hitherto avoided to dis¬
tract my readers’ attention. At the time when
he wrote, he does not appear to have made
many proselytes; the extravagant and alarming
consequences in which his system terminated,
serving with most persons as a sufficient anti¬
dote against it. Clarke was probably the first
who perceived distinctly the logical accuracy of
his reasoning; and that, if the principles were
admitted, it was impossible to resist the conclu¬
sions deduced from them.2 * It seems to have
been the object both of Leihnitz and of Collins,
to obviate the force of this indirect argument
against the scheme of necessity, by attempting
to reconcile it with the moral agency of man ;
a task which, I think, it must be allowed, was
much less ably and plausibly executed by the
former than by the latter. Convinced, on the
other hand, that Spinoza had reasoned from his
premises much more rigorously than either Col¬
lins or Leibnitz, Clarke bent the whole force of
his mind to demonstrate that these premises
were false; and, at the same time, to put in¬
cautious reasoners on their guard against the
seducing sophistry of his antagonists, by show¬
ing, that there was no medium between admit¬
ting the free-agency of man, and of acquiescing
in all the monstrous absurdities which the creed
of Spinoza involves.
Spinoza,5 it may be proper to mention, was an
Amsterdam Jew of Portuguese extraction, who
(with a view probably to gain a more favourable
reception to his philosophical dogmas) withdrew
himself from the sect in which he had been edu¬
cated, and afterwards appears to have lived
chiefly in the society of Christians;4 without,
however, making any public profession of the
Christian faith, or even submitting to the cere¬
mony of baptism. In his philosophical creed,
he at first embraced the system of Descartes,
1 In speaking disrespectfully of the personal character of Hobbes, I allude to the base servility of his political principles,
and to the suppleness with which he adapted them to the opposite interests of the three successive governments under which
his literary life was spent. To his private virtues the most honourable testimony has been borne, both by his friends and
by his enemies.
2 Dr Reid’s opinion on this point coincides exactly with that of Clarke. See his Essays on the Active Powers o] Man,
(p. 289, 4to. Edition), where he pronounces the system of Spinoza to be “ the genuine, and the most tenable system of ne¬
cessity.”
5 Born 1632, died 1677- It is observed by Bayle, that “ although Spinoza was the first who reduced Atheism to a sys¬
tem, and formed it into a body of doctrine, connected according to the method of geometricians, yet, in other respects, his
opinion is not new, the substance of it being the same with that of several other philosophers, both ancient and modern,
European and Eastern.”—See his Diet. art. Spinoza, and the authorities in Note S.
It is asserted by a late German writer, that “ Spinoza has been little heard of in England, and not at all in France, and
that he has been zealously defended and attacked by Germans alone.” The same writer informs us, that “ the philosophy
of Leibnitz has been little studied in France, and not at all in England.”—(Lectures on the History of Literature, by Fred
Schlegel. English Transl. published at Fdin. 1818. Vob II. p. 243.)
Is it possible that an author who pronounces so dogmatically upon the philosophy of England, should never have heard
the name of Dr Clarke ?
4 The Synagogue were so indignant at his apostacy, that they pronounced against him their highest sentence of excom-
munication called Schammata. The form of the sentence may be found in the Treatise of Selden, De Jure Naturae et Gentium,
Lib. IV. c. 7. It is a document of some curiosity, and will scarcely suffer by a comparison with the Popish form of ex-
communication recorded by Sterne. For some farther particulars with respect to Spinoza see Note LL.
DISSERTATION FIRST.
145
and began his literary career with a work en¬
titled, Renati Descartes Principiorum Philoso¬
phic, Pars Prima et Secunda, More Geometrico
Demonstrate, 1663. It was, however, in little
else than his physical principles that he agreed
with Descartes; for no two philosophers ever
differed more widely in their metaphysical and
theological tenets. Fontenelle characterises his
system as a {< Cartesianism pushed to extra¬
vagance” (une Cartesianisme outree) ; an expres¬
sion which, although far from conveying a just
or adequate idea of the whole spirit of his
doctrines, applies very happily to his boldness
and pertinacity in following out his avowed
principles to the most paradoxical consequences
which he conceived them to involve. The re¬
putation of his writings, accordingly, has fallen
entirely (excepting perhaps in Germany and in
Holland) with the philosophy on which they
were grafted; although some of the most ob¬
noxious opinions contained in them are still,
from time to time, obtruded on the world, un¬
der the disguise of a new form, and of a phra¬
seology less revolting to modern taste.1 2 3 *
In no part of Spinoza’s works has he avowed
himself an atheist; hut it will not be disputed,
by those who comprehend the drift of his rea¬
sonings, that, in point of practical tendency,
Atheism and Spinozism are one and the same.
In this respect, we may apply to Spinoza (and
I may add to Yanini also) what Cicero has said
of Epicurus, Verbis reliquit Deos, re sustulit;—
a remark which coincides exactly with an ex¬
pression of Newton’s in the Scholium at the end
of the Principia: “ Deus sine dominio, provi-
dentia, et causis finalibus, nihil aliud est quam
Fatum et Natura.”*
Among other doctrines of natural and reveal¬
ed religion, which Spinoza affected to embrace,
was that of the Divine Omnipresence; a doc¬
trine which, combined with the Plenum of Des¬
cartes, led him, by a short and plausible process
of reasoning, to the revival of the old theory
which represented God as the sold of the world;
or rather to that identification of God and of
the material universe, which I take to be still
more agreeable to the idea of Spinoza.5 I am
particularly anxious to direct the attention of
my readers to this part of his system, as I con¬
ceive it to be at present very genei'ally misrepre-
1 “ On vient de proposer a 1’Academie de Berlin, pour sujet de concours: “ Quels sont les points de contact du Car-
tdsianisme et du systeme de Spinoza ?”—(Recherches Philosophiques, par M. de Ronald, 1818.)
2 One of the most elaborate and acute refutations of Spinozism which has yet appeared is to be found in Bayle’s Dic¬
tionary, where it is described as “ the most monstrous scheme imaginable, and the most diametrically opposite to the
clearest notions of the mind.”—The same author affirms, that ^ it has been fully overthrown even by the weakest of its
adversaries.”—“ It does not, indeed, appear possible” (as Mr Maclaurin has observed) “ to invent another system equally
absurd; amounting (as it does in fact) to this proposition, that there is but one substance in the universe, endowed with
infinite attributes (particularly infinite extension and cogitation), which produces all other things necessarily as its own
modifications, and which alone is, in all events, both physical and moral, at once cause and effect, agent and patient—View
of Newton's Discoveries, Book I. Chap. 4.
3 Spinoza supposes that there are in God two eternal properties, thought and extension; and as he held, with Descartes,
that extension is the essence of matter, he must necessarily have conceived materiality to be an essential attribute of God.
“ Per Corpus intelligo modum, qui Dei essentiam quatenus ut res extensa consideratur, certo et determinate modo expri-
mit.” CEthica ordine Geometrico Demonstrate, Pars 2. Defin. I. See also Ethic. Pars 1. Prop. 14.) With respect to the other
attributes of God, he held, that God is the cause of all things ; but that he acts, not from choice, but from necessity; and of
consequence, that he is the involuntary author of all the good and evil, virtue and vice, which are exhibited in human life.
“ Res nullo alio modo, neque alio ordine a Deo produci potuerunt, quam productse sunt.”—Ibid. Pars 1. Prop. 33.) In one
of his letters to Mr Oldenburgh (Letter 21), he acknowledges, that his ideas of God and of nature were very different
from those entertained by modern Christians; adding by way of explanation, “ Deum rerum omnium causam immanentem,
non vero transeuntem statuo;”—an expression to which I can annex no other meaning but this, that God is inseparably
and essentially united with his works, and that they form together but one being.
The diversity of opinions entertained concerning the nature of Spinozism has been chiefly owing to this, that some have
formed their notions of it from the books which Spinoza published during his life, and others from his posthumous re¬
mains. It is in the last alone (particularly in his Ethics) that his system is to be seen completely unveiled and undisguis¬
ed. In the former, and also in the letters’ addressed to his friends, he occasionally accommodates himself, with a very tem¬
porising spirit, to what he considered as the prejudices of the world. In proof of this, see his Tractatus rheologico-Politicus,
and his epistolary correspondence, passim; above all, his letter to a young friend who had apostatised from Protestantism
to the Catholic Church. The letter is addressed, “ Nobilissimo Juveni, Alberto Burgh."—(Spin. Op. T. II. p. 095.)
The edition of Spinoza’s works to which mv references are made, is the complete and very accurate one published at
Jena in 1802, by Henr. Eberh. Gottlob Paulus, who styles himself Doctor and Professor of Theology.
This learned divine is at no pains to conceal his admiration of the character as well as talents of his author; noi does he
seem to have much to object to the system of Spinozism, as explained in his posthumous work upon Ethics ; a work which,
the editor admits, contains the only genuine exposition of Spinoza’s creed. “ Sedes systematis quod sibi cqndidit in ethica
est.”—(Prcef. Iteratce Editionis, p. ix.) In what manner all this was reconciled in his theological lectures with the doctrines
either of natural or of revealed religion, it is not verv easy to imagine. Perhaps he only affords a new example of what
DISS. I. PART II. T
146
PRELIMINARY DISSERTATIONS.
sented, or, at least, very generally misunder¬
stood ; a thing not to he wondered at, consider¬
ing the total neglect into which his works have
long fallen. It is only in this way I can ac¬
count for the frequent use which has most un¬
fairly been made of the term Spinozism to stig¬
matise and discredit some doctrines, or rather
some modes of speaking, which have been sanc¬
tioned, not only by the wisest of the ancients,
hut by the highest names in English philosophy
and literature; and which, whether right or
wrong, will he found, on a careful examina¬
tion and comparison, not to have the most dis¬
tant affinity to the absurd creed with which
they have been confounded. I am afraid that
Pope, in the following lines of the Dunciad,
suffered himself so far to be misled by the ma¬
lignity of Warhurton, as to aim a secret stab
at Newton and Clarke, by associating their figu¬
rative, and not altogether unexceptionable lan¬
guage, concerning space (when they called it
the sensorium of the Deity), with the opinion of
Spinoza, as I have just explained it.1
“ Thrust some Mechanic Cause into His place,
Or bind in matter, or diffuse in space."
Dr Clarke long ago remarked, that “ Believing too much and too little have commonly the luck to meet together, like two
things moving contrary ways in the same circle.”—(Third Letter to Dodwell.)
A late German writer, who, in his own opinions, has certainly no leaning towards Spinozism, has yet spoken of the mo¬
ral tendency of Spinoza’s writings, in terms of the warmest praise. “ The morality of Spinoza (says M. b red. Schlegel)
is not indeed that of the Bible, for he himself was no Christian, but it is still a pure and noble morality, resembling that of
the ancient Stoics, perhaps possessing considerable advantages over that system. That which makes him strong when op¬
posed to adversaries who do not understand or feel his depth, or who unconsciously have fallen into errors not much diffe¬
rent from his, is not merely the scientific clearness and decision of his intellect, but in a much higher degree the openhearted¬
ness, strong feeling, and conviction, with which all that he says seems to gush from his heart and soul.’ —(Led. of Fred.
Schlegel, Eng. Transl. Yol. II. p. 244.) The rest of the passage, which contains a sort of apology for the system of Spinoza,
is still more curious.
Although it is with the metaphysical tenets of Spinoza alone that we are immediately concerned^ at present, it is not al¬
together foreign to my purpose to observe, that he had also speculated much about the principles of government; and that
the coincidence of his opinions with those of Hobbes, on this last subject, was not less remarkable than the similarity of
their views on the most important questions of metaphysics and ethics. Unconnected as these different branches of know¬
ledge may at first appear, the theories of Spinoza and of Hobbes concerning all of them, formed parts of one and the same
system; the whole terminating ultimately in the maxim with which, according to Plutarch, Anaxarchus consoled Alex¬
ander after the murder of Clytus: riav ro avo rob xodrouroe hxalov inai. Even in discussing the question about Liber¬
ty and Necessity, Hobbes cannot help glancing at this political corollary. “ The power of God alone is a sufficient justifica¬
tion of any action he doth.” “ That which he doth is made just by his doing it.” “ Power irresistible justifies
all actions really and properly, in whomsoever it be found.”—(Of Liberty and Necessity, addressed to the Lord Marquis of
Newcastle.) Spinoza has expressed himself exactly to the same purpose—(See his Tractatus Politicus, Cap. 2. §§ 3, 4.) So
steadily, indeed, is this practical application of their abstract principles kept in view by both these writers, that not one
generous feeling is ever suffered to escape the pen of either in favour of the rights, the liberties, or the improvement of
their species.
The close affinity between those abstract thories which tend to degrade human nature, and that accommodating morality
which prepares the minds of men for receiving passively the yoke of slavery, although too little attended to by the writers
of literary history, has not been overlooked by those deeper politicians who are disposed (as has been alleged of the first of
the Cajsars) to consider their fellow-creatures “ but as rubbish in the way of their ambition, or tools to be employed in re¬
moving it.” This practical tendency of the Epicurean philosophy is remarked by one of the wisest of the Homan states¬
men ; and we learn from the same high authority, how fashionable this philosophy was in the higher circles of his country¬
men, at that disastrous period which immediately preceded the ruin of the Republic. “ Nunquam audivi in Epicuri schola,
Lycurgum, Solonem, Miltiadem, Themistoclem, Epaminondam, nominari; qui in ore sunt cseterorum omnium philoso-
phorum.”—(Be Fin. Lib. ii. c. 21.) “ Nec tamen Epicuri licet oblivisci, si cupiam ; cujus imaginem non modo in tabulis
nostri familiares, sed etiam in poculis, et annulis habent ”—(Ibid. Lib- v. c. 1.)
The prevalence of Hobbism at the court of Charles II. (a fact acknowledged by Clarendon himself) is but one of the
many instances which might be quoted from modern times in confirmation of these remarks.
The practical tendency of such doctrines as would pave the way to universal scepticism, by holding up to ridicule the
extravagancies and inconsistencies of the learned, is precisely similar. We are told by Tacitus (Jlwwa/. Lib. 14), that
Nero was accustomed, at the close of a banquet, to summon a party of philosophers, that he might amuse himself with lis¬
tening to the endless diversity and discordancy of their respective systems: nor were there wanting philosophers at
Rome, the same historian adds, who were flattered to be thus exhibited as a spectacle at the table of the Emperor. What a
deep and instructive moral is conveyed by this anecdote ! and what a contrast does it afford to the sentiment of one of
Nero’s successors, who was himself a philosopher in the best sense of the word, and whose reign furnishes some of the
fairest pages in the annals of the human race ! “ I search for truth (says Marcus Antoninus), by whi#h no person has
ever been injured.” yao riiv ukrihiav, Us ibiis oruvroli sSxaliti.
1 Warburton, indeed, always^rq/mes great respect for Newton ; but of his hostility to Clarke it is unnecessary to produce
any other proof than his note on the following line of the Dunciad:
“ Where Tindal dictates, and Silenus snores.”—B. iv. 1. 492.
May I venture to add, that the noted line of the Essay on Man,
“ And showed a Newton as we show an ape,”
could not possibly have been written by any person impressed with a due veneration for this glory of his species ?
DISSERTATION FIRST.
147
How little was it suspected by the poet, when
this sarcasm escaped him, that the charge of
Spinozism and Pantheism was afterwards to be
brought against himself, for the sublimest pas¬
sage to be found in his writings !
“ All are but parts of one stupendous whole,
Whose body Nature is, and God the soul.
* * - * *
Lives through all Life, extends through all extent,
Spreads undivided, operates unspent.”1
Bayle was, I think, the writer who first led the
way to this misapplication of the term Spinozism ;
and his object in doing so was plainly to destroy
the effect of the most refined and philosophical
conceptions of the Deity which were ever formed
by the unassisted power of human reason.
“ Estne Dei sedes nisi terra, et pontus, et aer,
Et coelum, et virtus ? Superos quid quserimus ultra ?
Jupiter est quodcumque vides, quocumque moveris.”
“ Is there a place that <3ed would choose to love
Beyond this earth, the seas, yon Heaven above.
And virtuous minds, the noblest throne for Jove;
Why seek we farther then ? Behold around,
How all thou seest does with the God abound,
Jove is alike to all, and always to be found.”
Rowe’s Lucan.
Who but Bayle, could have thought of extract¬
ing anything like Spinozism from such verses as
these !
On a subject so infinitely disproportioned to
our faculties, it is vain to expect language which
will bear a logical and captious examination.
Even the Sacred Writers themselves are forced
to adapt their phraseology to the comprehension
of those to whom it is addressed, and frequently
borrow the figurative diction of poetry to convey
ideas which must be interpreted, not according
to the letter, but the spirit of the passage. It is
thus that thunder is called the voice of God;
the wind, His breath; and the tempest, the blast
of His nostrils. Not attending to this circum¬
stance, or rather not choosing to direct to it the
attention of his readers, Spinoza has laid hold
of the well known expression of St Paul, that
“ in God we live, and move, and have our being,”
as a proof that the ideas of the apostle, concern¬
ing the Divine Nature, were pretty much the
same with his own; a consideration which, if
duly weighed, might have protected some of the
passages above quoted from the uncharitable cri¬
ticisms to which they have frequently been ex¬
posed.2
To return, however, to Collins, from whose
controversy with Clarke I was insensibly led
aside into this short digression about Spinoza:
1 This passage, as War ton has remarked, bears a very striking analogy to a noble one in the old Orphic verses quoted in
the treatise Ko<rgs, ascribed to Aristotle; and it is not a little curious, that the same ideas occur in some specimens ot
Hindoo poetry, translated by Sir W. Jones; more particularly in the Hymn to Narrayna, or the Spirit of God, taken, as
he informs us, from the writings of their ancient authors :
Omniscient Spirit, whose all-ruling power
Bids from each sense bright emanations beam;
Glows in the rainbow, sparkles in the stream,
&c. &c.
* Mr Gibbon, in commenting upon the celebrated lines of Virgil,
“ Spiritus intus alit, totamque infusa per artus,
“ Mens agitat molem, et magno se corpore miscet,”
observes, that “ the mind which is infused into the different parts of matter, and which mingles itself with the mighty
mass, scarcely retains any property of a spiritual substance, and bears too near an affinity to the principles which the im¬
pious Spinoza revived rather than invented.” He adds, however, that “ the poverty of human language, and the obscu¬
rity of human ideas, make it difficult to speak worthily of the great first cause ; and that our most religious, poets
(particularly Pope and Thomson), in striving to express the presence and energy of the Deity in every part of the universe,
deviate unwarily into images which require a favourable construction. But these writers (he candidly remarks) deserve that
favour, by the sublime manner in which they celebrate the Great Father of the universe, and by those effusions of love
and gratitude which are inconsistent with the materialist’s system.”—{Misc. Works, Vol. II. pp. 509,. 510.)
May I be permitted here to remark, that it is not only difficult but impossible to speak of the omnipresence and omnipo¬
tence of God, without deviating into such images ?
With the doctrine of the Anima Mundi, some philosophers, both ancient and modern, have connected another theory,
according to which the souls of men are portions of the Supreme Being, wdth whom they are re-united at death, and in
whom they are finally absorbed and lost. To assist the imagination in conceiving this theory, death has been, compared to
the breaking of a phial of water, immersed in the ocean. It is needless to say, that this incomprehensible jargon has no
necessary connection with the doctrine which represents God as the soul of the world, and that it would have been
loudly disclaimed, not only by Pope and Thomson, but by Epictetus, Antoninus, and all the wisest and soberest of the
Stoical school. Whatever objections, therefore, may be made to this doctrine, let not its supposed consequences be cnxigea
upon any but those who may expressly avow them. On such a subject, as Gibbon has well remarked, “ we should be slow
to suspect, and still slower to condemn.”—(/6id. p. 510.)
Sir William Jones mentions a very curious modification of this theory of absorption, as one ot the doctrines of the Vedanta
school. “ The Vedanta school represent Elysian happiness as a total absorption, though not such as to destroy consciousness,
in the Divine Essence.”—(Dissertation on the Gods of Greece, Italy, and India.)
148
PRELIMINARY DISSERTATIONS.
I have already said, that it seems to have heen
the aim of Collins to vindicate the doctrine of
Necessity from the reproach brought on it by its
supposed alliance with Spinozism ; and to retort
upon the partizans of free-will the charges of
favouring atheism and immorality. In proof of
this I have only to quote the account given by
the author himself, of the plan of his work:
t( Too much care cannot he taken to prevent
being misunderstood and prejudged, in handling
questions of such nice speculation as those of
Liberty and Necessity; and, therefore, though I
might in justice expect to he read before any
judgment he passed on me, I think it proper to
premise the following observations :
“1. First, Though I deny liberty in a certain
meaning of that word, yet I contend for liberty,
as it signifies a power in man to do as he wills or
pleases.
“ 2. Secondly, When I affirm necessity, I con¬
tend only for moral necessity ; meaning thereby,
that man, who is an intelligent and sensible
being, is determined by his reason and his senses;
and I deny man to he subject to such necessity
as is in clocks, watches, and such other beings,
which, for want of sensation and intelligence,
are subject to an absolute, physical, or mecha¬
nical necessity.
“ 3. Thirdly, I have undertaken to show, that
the notions I advance are so far from being in¬
consistent with, that they are the sole founda¬
tions of morality and laws, and of rewards and
punishments in society; and that the notions I
explode are subversive of them.”1 *
In the prosecution of his argument on this
question, Collins endeavours to show, that man
is a necessary agent, 1. From our experience.
(By experience he means our own consciousness
that we are necessary agents.) 2. From the
impossibility of liberty.* 8. From the conside¬
ration of the Divine prescience. 4. From the
nature and use of rewards and punishments;
and 5. From the nature of morality.3
In this view of the subject, and, indeed, in the
very selection of his premises, it is remarkable
how completely Collins has anticipated Dr Jona¬
than Edwards, the most celebrated and indis¬
putably the ablest champion of the scheme of
Necessity who has since appeared. The coinci¬
dence is so perfect, that the outline given by the
former, of the plan of his work, might have
served with equal propriety as a preface to that
of the latter.
From the above summary, and still more from
the whole tenor of the Philosophical Inquiry, it is
evident, that Collins (one of the most obnoxious
writers of his day to divines of all denomina¬
tions) was not less solicitous than his successor
Edwards to reconcile his metaphysical notions
with man’s accountableness and moral agency.
The remarks, accordingly, of Clarke upon Col¬
lins’s work, are equally applicable to that of Ed¬
wards. It is to be regretted that they seem
never to have fallen into the hands of this very
acute and honest reasoner. As for Collins, it is
a remarkable circumstance, that he attempted
no reply to this tract of Clarke’s, although he
lived twelve years after its publication. The
reasonings contained in it, together with those
on the same subject in his correspondence with
Leibnitz, and in his Demonstration of the Being
and Attributes of God, form, in my humble opi¬
nion, the most important as well as powerful
of all his metaphysical arguments.4 The ad¬
versaries with whom he had to contend were,
both of them, eminently distinguished by inge¬
nuity and subtlety, and he seems to have put
forth to the utmost his logical strength, in con¬
tending with such antagonists. “ The liber¬
ty or moral agency of man (says his friend
Bishop Hoadly) was a darling point to him. He
excelled always, and showed a superiority to all,
whenever it came into private discourse or pub¬
lic debate. But he never more excelled than
when he was pressed with the strength Leibnitz
was master of; which made him exert all his
1 A Philosophical Inquiry concerning Human Liberty, 3d edit. Lend. 1735.
* See Note MM.
* See Note N N.
4 \ oltaire, who, in all probability, never read either Clarke or Collins, has said that the former replied to the latter only
by Theological reasonings: “ Clarke n'a repondu a Collins qu'en Theologien."—(Quest, sur 1'Encyclopedic, Art. Liberte.) Nothing
can be more remote from the truth. The argument of Clarke is wholly Metaphysical; whereas, his antagonist, in various
instances, has attempted to wrest to his own purposes the words of Scripture.
DISSERTATION FIRST.
149
talents to set it once again in a clear light, to
guard it against the evil of metaphysical obscu¬
rities, and to give the finishing stroke to a sub¬
ject which must ever he the foundation of mo¬
rality in man, and is the ground of the account¬
ableness of intelligent creatures for all their
actions.”1 2 *
It is needless to say, that neither Leibnitz nor
Collins admitted the fairness of the inferences
which Clarke conceived to follow from the
scheme of necessity : But almost every page in
the subsequent history of this controversy may
be regarded as an additional illustration of the
soundness of Clarke’s reasonings, and of the sa¬
gacity with which he anticipated the fatal er¬
rors likely to issue from the system which he
opposed.
c< Thus (says a very learned disciple of Leib¬
nitz, who made his first appearance as an author
about thirty years after the death of his mas¬
ter)*—thus, the same chain embraces the phy¬
sical and moral worlds, binds the past to the
present, the present to the future, the future to
eternity.”
“ That wisdom which has ordained the ex¬
istence of this chain, has doubtless willed that
of every link of which it is composed. A Ca¬
ligula is one of those links, and this link is
of iron : A Marcus Aurelius is another link,
and this link is of gold. Both are necessary
parts of one whole, which could not but exist.
Shall God then be angry at the sight of the iron
link ? What absurdity ! God esteems this
link at its proper value: He sees it in its cause,
and he approves this cause, for it is good. God
beholds moral monsters as he beholds physical
monsters. Happy is the link of gold ! Still more
happy if he know that he is only fortunate* He
has attained the highest degree of moral perfec¬
tion, and is nevertheless without pride, knowing
that what he is, is the necessary result of the
place which he must occupy in the chain.”
“ The gospel is the allegorical exposition of
this system ; the simile of the potter is its sum¬
mary.”4 (Bonnet, T. VIII. pp. 237, 238.)
In what essential respect does this system
differ from that of Spinoza? Is it not even
more dangerous in its practical tendency, in
consequence of the high strain of mystical devo¬
tion by which it is exalted ?*
This objection, however, does not apply to
the quotations which follow. They exhibit,
without any colourings of imagination or of en¬
thusiasm, the scheme of necessity pushed, to the
remotest and most alarming conclusions which
it appeared to Clarke to involve; and as they
express the serious and avowed creed of two of
our contemporaries (both of them men of dis¬
tinguished talents), may be regarded as a proof,
that the zeal displayed by Clarke against the
1 Preface to the folio ed. of Clarke’s Works.—The vital importance which Clarke attached to this question, has given
to the concluding paragraphs of his remarks on Collins, an earnestness and a solemnity of which there are not many instances
in his writings. These paragraphs cannot be too strongly recommended to the attention of those well-meaning persons,
who, in our own times, have come forward as the apostles of Dr Priestley’s “ great and glorious Doctrine of Philosophical
Necessity.”
2 Charles Bonnet, born 1720, died 1793.
5 The words in the original are, “ Heureux le chainon d’or ! plus heureux encore, s’il sait qu’il n’est qu’ heureux." The
double meaning of heureux, if it render the expression less logically precise, gives it at least an epigrammatic turn, which
cannot be preserved in our language.
4 See Note O O.
8 Among the various forms which religious enthusiasm assumes, there is a certain prostration of the mind, which, under
the specious disguise of a deep humility, aims at exalting the Divine perfections, by annihilating all the powers which
belong to Human Nature. “ Nothing is more usual for fervent devotion (says Sir James Mackintosh, in speaking of
some theories current among the Hindoos), than to dwell so long and so warmly on the meanness and worthlessness of
created things, and on the all-sufficiency of the Supreme Being, that it slides insensibly from comparative to absolute lan¬
guage, and in the eagerness of its zeal to magnify the Deity seems to annihilate everything else.”—(See Philosophy oj
the Human Mind, Vol. II. p. 529, 2d ed.)
This excellent observation may serve to account for the zeal displayed by Bonnet, and many other devout men, in fa¬
vour of the Scheme of Necessity. “ We have nothing (they frequently and justly remind us) but what we have re¬
ceived.”—But the question here is simply a matter of fact, whether we have or have not received from God the gift of
Free Will; and the only argument, it must be remembered, which they have yet been able to advance for the nega¬
tive proposition, is, that this gift was impossible, even for the power of God ; nay, the same argument which annihi¬
lates the power of Man, annihilates that of God also, and subjects him, as well as all his creatures, to the control of
causes which he is unable toOresist. So completely does this scheme defeat the pious views in which it has sometimes
originated.—I say sometimes; for the very same argument against the liberty of the Will is employed by Spinoza, ac¬
cording to whom the free-agency of man* involves the absurd supposition of an imperium in imperio in the universe—
(Tructat. Polit. Cap. II. § 6.)
150
PRELIMINARY DISSERTATIONS.
metaphysical principles which led ultimately to
such results, was not so unfounded as some
worthy and able inquirers have supposed.
May I he permitted to observe farther on
this head, that, as one of these writers spent his
life in the pay of a German prince, and as the
other was the favourite philosopher of another
sovereign, still more illustrious, the sentiments
which they were so anxious to proclaim to the
world, may he presumed to have been not very
offensive, in their judgments, to the ears of their
protectors ?
“ All that is must be (says the Baron de
Grimm, addressing himself to the Duke of Saxe-
Gotha)—all that is must be, even because it
is ; this is the only sound philosophy; as long
as we do not know this universe a 'priori (as
they sav in the schools), all is necessity.1
Liberty is a word without meaning, as you
shall see in the letter of M. Diderot.”
The following passage is extracted from Di¬
derot’s letter here referred to :
“ I am now, my dear friend, going to quit
the tone of a preacher, to take, if I can, that of
a philosopher. Examine it narrowly, and you
will see that the word Liberty is a word devoid
of meaning;* that there are not, and that there
cannot he free beings; that we are only what
accords with the general order, with our organi¬
zation, our education, and the chain of events.
These dispose of us invincibly. We can no
more conceive a being acting without a motive,
than we can one of the arms of a balance acting
without a weight. The motive is always exte¬
rior and foreign, fastened upon us by some
cause distinct from ourselves. What deceives
us, is the prodigious variety of our actions,
joined to the habit which we catch at our birth,
of confounding the voluntary and the free. We
have been so often praised and blamed, and
have so often praised and blamed others, that
we contract an inveterate prejudice of believing
that we and they will and act freely. But if there
is no liberty, there is no action that merits either
praise or blame; neither vice nor virtue, no¬
thing that ought either to he rewarded or punish¬
ed. What then is the distinction among men ?
The doing of good and the doing of ill! The
doer of ill is one who must be destroyed, not
punished. The doer of good is lucky, not vir¬
tuous. But though neither the doer of good or
of ill he free, man is nevertheless a being to
he modified ; it is for this reason the doer of ill
should be destroyed upon the scaffold. From
thence the good effects of education, of plea¬
sure, of grief, of grandeur, of poverty, &c.;
from thence a philosophy full of pity, strongly
attached to the good, nor more angry with the
wicked, than with the whirlwind which fills
one’s eyes with dust. Strictly speaking, there
is hut one sort of causes, that is, physical
causes. There is hut one sort of necessity,
which is the same for all beings. This is what
reconciles me to h umankind: it is for this rea¬
son I exhorted you to philanthropy. Adopt
these principles if you think them good, or show
me that they are bad. If you adopt them,
they will reconcile you too with others and
with yourself: you will neither be pleased nor
angry with yourself for being what you are.
Reproach others for nothing, and repent of
nothing; this is the first step to wisdom. Be¬
sides this, all is prejudice and false philosophy.” 3
The prevalence of the principles here so earnest¬
ly inculcated among the higher orders in France,
at a period somewhat later in the history of the
monarchy, may he judged of from the occasion¬
al allusions to them in the dramatic pieces then
chiefly in request at Paris. In the Manage de
Figaro (the popularity of which was quite un-
1 The logical inference ought undoubtedly to have been, “ as long as we know nothing of the universe a prion, we
are not entitled to say of anything that it either is, or is not, necessary.”
2 Does not this remark of Diderot apply with infinitely greater force to the word necessity, as employed in tins oon-
3 Nearly to the same purpose, we are told by Mr Belsham, that “ the fallacious feeling o? remorse is superseded by the doc¬
trine of necessity.” {Elem. p. 284.) And again, “ Remorse supposes free will. It is of little or no use in moral disci¬
pline. In a degree, it is even pernicious.”—fj&wZ. p. 406.) . ^
Nor does the opinion of Hartley seem to have been different. “ The doctrine of Necessity has a tendency to abate all
resentment against men. Since all they do against us is by the appointment of God, it is rebellion against him to be offend¬
ed with them.”
j?or the originals of the quotations from Grimm and Diderot, see Note P P.
DISSERTATION FIRST.
151
exampled), the hero of the piece, an intriguing
valet in the service of a Spanish courtier, is in¬
troduced as thus moralising, in a soliloquy on
his own free-agency and personal identity. Such
an exhibition upon the English stage would have
been universally censured as out of character and
extravagant, or rather, would have been com¬
pletely unintelligible to the crowds by which our
theatres are filled.
“ Oh bisarre suite d’evenemens ! Comment
cela m’a-t-il arrive ? Pourquoi ces choses et non
pas d’autres ? Qui les a fixees sur ma tete ?
Force de parcourir la route ou je suis entre sans
le savoir, comme j’en sortirai sans le vouloir, je
Tai jonchee d’autant de fleurs que ma gaiete me
la permit: encore je dis ma gaiete, sans savoir
si elle est a moi plus que le reste, ni meme qui
est ce moi dont je m’occupe.”
That this soliloquy, though put into the mouth
of Figaro, was meant as a picture of the philo¬
sophical jargon at that time affected by courtiers
and men of the world, will not be doubted by
those who have attended to the importance of
the rolles commonly assigned to confidential valets
in French comedies, and to the habits of fami¬
liarity in which they are always represented as
living with their masters. The sentiments which
they are made to utter may, accordingly, be
safely considered as but an echo of the lessons
which they have learned from their superiors.1 *
My anxiety to state, without any interruption,
my remarks on some of the most important
questions to which the attention of the public
was called by the speculations of Locke, of
Leibnitz, of Newton, and of Clarke, has led me,
in various instances, to depart from the strict
order of Chronology. It is time for me, how¬
ever, now to pause, and, before I proceed far¬
ther, to supply a few chasms in the foregoing
sketch.
SECTION IV.
Of some Authors who have contributed, by their Critical or Historical Writings, to diffuse a Taste for
Metaphysical Studies.—Bayle—Fontenelle—Addison. Metaphysical Works of Berkeley.
Among the many eminent persons who were
either driven from France, or who went into
voluntary exile, in consequence of the revoca¬
tion of the edict of Nantz, the most illustrious by
far was Bayle;8 who, fixing his residence in
Holland, and availing himself, to the utmost ex¬
tent, of the religious toleration then enjoyed in
that country, diffused from thence, over Europe,
a greater mass of accurate and curious informa¬
tion, accompanied by a more splendid display of
acute and lively criticism, than had ever before
come from the pen of a single individual.3 * * * *
Happy ! if he had been able to restrain within
due bounds his passion for sceptical and licenti¬
ous discussion, and to respect the feelings of tfie
wise and good, on topics connected with religion
1 A reflection of Voltaire’s on the writings of Spinoza may, I think, be here quoted without impropriety. “ Vous etes
tres confus, Baruc Spinoza, mais etes vous aussi dangereux qu’on le dit ? Je soutiens que non, et ma raison c’est que vous
etes confus, que vous avez dcrit en mauvais Latin, et qu’il n'y a pas dix personnes en Europe qui vous hsent d un bout a
I’autre. Quel est 1’auteur dangereux ? C’est celui qui est lu par les Oisifs de la Cour, et par les Dames. —f Quest, sur
1 ^Had Voltaie^epVthis last remark steadily in view in his own writings, how many of those pages would he have cancel¬
led which he has given to the world !
3 The1 erudition of Bayle is greatly undervalued by his antagonist Le Clerc. “ Toutes les lumieres philosoplnques.de
M. Bayle consistoient en quelque peu de Pdripatdtisme, qu’il avoit appris des Je'suites de Toulouse, et un peu de Gartesia-
nisme, qu’il n’avoit iamais approfondi.”—(Bib. Choisie, Tom. XII. p. 100.) _ , c „
In the judgment of Gibbon, “ Bavle’s learning was chiefly confined to the Latin authors ; and he had more of a certain
multifarious reading than of real erudition. Le Clerc, his great antagonist, was as superior to him in that respect as in^rmr
in every other.”—[Extraits Raisonnts de rnes Lectures, p. 62.)
152
PRELIMINARY DISSERTATIONS.
and morality. But, in the peculiar circum¬
stances in which he was educated, combined
with the seducing profession of a literary ad¬
venturer, to which his hard fortune condemned
him, such a spirit of moderation was rather to
be wished than expected.
When Bayle first appeared as an author, the
opinions of the learned still continued to be di¬
vided between Aristotle and Descartes. A con¬
siderable number leaned, in secret, to the meta¬
physical creed of Spinoza and of Hobbes; while
the clergy of the Roman Catholic and the Pro¬
testant churches, instead of uniting their efforts
in defence of those truths which they professed
in common, wasted their strength against each
other in fruitless disputes and recriminations.
In the midst of these controversies, Bayle,
keeping aloof as far as possible from all the
parties, indulged his sceptical and ironical hu¬
mour at the common expence of the various
combatants. Unattached himself to any sys¬
tem, or, to speak more correctly, unfixed in his
opinions on the most fundamental questions, he
did not prosecute any particular study with
sufficient perseverance to add materially to the
stock of useful knowledge. The influence, how¬
ever, of his writings on the taste and views of
speculative men of all persuasions, has been so
great, as to mark him, out as one of the most
conspicuous characters of his age; and I shall
accordingly devote to him a larger space than
may, at first sight, appear due to an author who
has distinguished himseif only by the extent of
his historical researches, and by the sagacity and
subtlety of his critical disquisitions.
We are informed by Bayle himself, that his
favourite authors, during his youth, were Plu¬
tarch and Montaigne; and from them, it has
been alleged by some ot his biographers, he im¬
bibed his first lessons of scepticism. In what
manner the first of these writers should have
contributed to inspire him with this temper of
mind, is not very obvious. There is certainly
no heathen philosopher or historian whose mo¬
rality is more pure or elevated; and none who
has drawn the line between superstition and re¬
ligion with a nicer hand.1 Pope has with per¬
fect truth said of him, that “ he abounds more
in strokes of good nature than any other au¬
thor;” to which it may be added, that he abounds
also in touches of simple and exquisite pathos,
seldom to be met with among the greatest paint¬
ers of antiquity. In all these respects what a
contrast does Bayle present to Plutarch !
Considering the share which Bayle ascribes
to Montaigne’s Essays in forming his literary
taste, it is curious, that there is no separate
article allotted to Montaigne in the Historical
and Critical Dictionary. What is still more
curious, there is more than one reference to
this article, as if it actually existed; without
any explanation of the omission (as far as I recol¬
lect) from the author or the publisher of the work.
Some very interesting particulars, however, con¬
cerning Montaigne’s life and writings, are scat¬
tered over the Dictionary, in the notices of other
persons, with whom his name appeared to Bayle
to have a sufficient connection to furnish an
apology for a short episode.
It does not seem to me a very improbable
conjecture, that Bayle had intended, and per¬
haps attempted, to write an account of Mon¬
taigne ; and that he had experienced greater
difficulties than he was aware of, in the execu¬
tion of his design. Notwithstanding their com¬
mon tendency to scepticism, no two characters
were ever more strongly discriminated in their
most prominent features; the doubts of the one
resulting from the singular coldness of his mo¬
ral temperament, combined with a subtlety and
over-refinement in his habits of thinking, which
rendered his ingenuity, acuteness, and erudition,
more than a match for his good sense and sa¬
gacity;—the indecision of the other partaking
1 See, in particular, his account of the effects produced on the character of Pericles by the sublime lessons of Anaxagoras.
Plutarch, it is true, had said before Bayle, that atheism is less pernicious than superstition; but low wide the difference
between this paradox, as explained and qualified by the Greek philosopher, and as interpreted and applied in the Reflectiom
on the Comet! Mr Addison himself seems to give his sanction to Plutarch’s maxim in one of his papers on Cheerfulness.
“ An eminent Pagan writer has made a discourse to show, that the atheist, who denies a God, does him less dishonour than
the man who owns his being, but, at the same time, believes him to be cruel, hard to please, and terrible to human nature.
For my own part, says he, I would rather it should be said of me, that there was never any such man as Plutarch, than
that Plutarch was ill-natured, capricious, and inhuman.”—(^Spectator, No. 494.)
DISSERTATION FIRST.
153
more of the shrewd and soldier-like etourderie of
Henry IV. when he exclaimed, after hearing
two lawyers plead on opposite sides of the same
question, “ Ventre St Gris ! il me sembk que tons
les deux ont raison.”
Independently of Bayle’s constitutional bias
towards scepticism, some other motives, it is
probable, conspired to induce him, in the com¬
position of his Dictionary, to copy the spirit and
tone of the old Academic school. On these col¬
lateral motives a strong and not very favourable
light is thrown by his own candid avowal in
one of his letters. “ In truth (says he to his
correspondent Minutoli), it ought not to be
thought strange, that so many persons should
have inclined to Pyrrhonism; for of all things
in the world it is the most convenient. You
may dispute with impunity against every body
you meet, without any dread of that vexatious
argument which is addressed ad hominem. You
are never afraid of a retort; for as you announce
no opinion of your own, you are always ready
to abandon those of others to the attacks of so¬
phists of every description. In a word, you
may dispute and jest on all subjects without in¬
curring any danger from the lex talionis.”1 It is
amusing to think, that the Pyrrhonism which
Bayle himself has here so ingeniously accounted
for, from motives of conveniency and of literary
cowardice, should have been mistaken by so
many of his disciples for the sportive triumph
of a superior intellect over the weaknesses and
errors of human reason.1 2 3 *
The profession of Bayle, which made it an
object to him to turn to account even the sweep¬
ings of his study, affords an additional explana¬
tion of the indigested mass of heterogeneous and
inconsistent materials contained in his Dictio¬
nary. Had he adopted any one system exclusive¬
ly, his work would have shrunk in its dimen¬
sions into a comparatively narrow compass.5
When these different considerations are ma¬
turely weighed, the omission by Bayle of the
article Montaigne will not be much regretted by
the admirers of the Essays. It is extremely
doubtful if Bayle would have been able to seize
the true spirit of Montaigne’s character; and,
at any rate, it is not in the delineation of charac¬
ter that Bayle excels. His critical acumen,
indeed, in the examination of opinions and
1 “ En verite, il ne faut pas trouver etrange que tant des gens aient donnd dans le Pyrrhonisme. Car c’est la chose du
monde le plus commode. Vous pouvez impunement disputer centre tous venans, et sans craindre ces argumens ad hominem,
qui font quelquefois tant de peine. Vous ne craignez point la retorsion; puisque ne soutenant rien, vous abandonnez de
bon coeur a tous les sophismes et a tous les raisonnemens de la terre quelque opinion quece soit. Vous n’etes jamais obligd
den venu a la defensive. En un mot, vous contestez et vous daubez sur toutes choses tout votre saoul, sans craindre la
peine du talion.”—(Oeuv. Div. de Bayle, IV. p. 537.)
“ The estimate formed by Warburton of Bayle’s character, both intellectual and moral, is candid and temperate. “ A
writer whose strength and clearness of reasoningcan only be equalled by the gaiety, easiness, and delicacy, of his wit; who,
pervading human nature with a glance, struck into the province of paradox, as an exercise for the restless vigour of his
mind: who, with a soul superior to the sharpest attacks ol fortune, and a heart practised to the best philosophy, had not
yet enough of real greatness, to overcome that last foible of superior geniuses, the temptation of honour, which the acade¬
mical exercise of wit is supposed to bring to its professors.—Legation.)
If there be anything objectionable in this panegyric, it is the unqualified praise bestowed on Bayle’s wit, which,
though it seldom fails in copiousness, in poignancy, or in that grave argumentative irony, by which it is still more characte¬
ristically marked, is commonly as deficient in gaiety and delicacy as that of Warburton himself.
Leibnitz seems perfectly to have entered into the peculiar temper of his adversary Bayle, when he said of him, that
“ the only way to make Bayle write usefully, would be to attack him when he advances propositions that are sound and
true; and to abstain from attacking him, when he says anything false or pernicious.”
“ Le vrai fnoyen de faire dcrire utilement M. Bayle, ce seroit de 1’attaquer, lorsqu’il dcrit des bonnes choses et vraies,
car ce seroit le moyen de le piquer pour continuer. Au lieu qu’il ne faudroit point 1’attaquer quand il en dit de mauvaises,
car cela 1’engagera a en dire d’autres aussi mauvaises pour soutenir les premieres.”.—(Tom. VI. p. 273.)
Leibnitz elsewhere says of him : Ubi bene, nemo melius.—(Tom. I. p. 257-)
3 “ The inequality of Bayle’s voluminous works (says Gibbon) is explained by his alternately writing for himself, for
the bookseller, and for posterity; and if a severe critic would reduce him to a single folio, that relic, like the books of the
Sybils, would become still more valuable.”—(Gibbon’s Mem. p. 50.)
Mr Gibbon observes in another place, that, “ if Bayle wrote his Dictionary to empty the various collections he had made,
without any particular design, he could not have chosen a better plan. It permitted him everything, and obliged him to
nothing. By the double freedom of a Dictionary and of Notes, he could pitch on what articles he pleased, and say what
he pleased on those articles.’-’—(Extraits Raisonnes de mes Lectures, p. G4.)
“ How could such a genius as Bayle,” says the same author, “ employ three or four pages, and a great apparatus of
learning, to examine whether Achilles was fed with marrow only; whether it was the max-row of lions and stags, or that
of lions only?” &c—(Ibid. p. CG.)
lor a long and interesting passage with respect to Bavle’s history and character, see Gibbon’s Memoirs, &c. Vol. I.
pp. 49, 50, 51.
DISS. I. PART II. U
154
PRELIMINARY DISSERTATIONS.
arguments, is unrivalled; but his portraits of
persons commonly exhibit only the coarser linea¬
ments which obtrude themselves on the senses
of ordinary observers; and seldom, if ever,
evince that discriminating and divining eye, or
that sympathetic penetration into the retire¬
ments of the heart, which lend to every touch
of a master artist, the never-to-be-mistaken ex¬
pression of truth and nature.
It furnishes some apology for the unsettled
state of Bayle’s opinions, that his habits of
thinking were formed prior to the discoveries of
the Newtonian School. Neither the vortices of
Descartes, nor the monads and pre-established
harmony of Leibnitz, were well calculated to
inspire him with confidence in the powers of the
human understanding; nor does he seem to have
been led, either by taste or by genius, to the study
of those exacter sciences in which Kepler, Galileo,
and others, had, in the preceding age, made such
splendid advances. In Geometry he never pro¬
ceeded beyond a few of the elementary proposi¬
tions ; and it is even said (although I apprehend
with little probability) that his farther progress
was stopped by some defect in his intellectual
powers, which disqualified him for the successful
prosecution of the study.
It is not unworthy of notice, that Bayle was
the son of a Calvinist minister, and was destin¬
ed by his father for his own profession; that
during the course of his education in a college
of Jesuits he was converted to the Roman Ca¬
tholic persuasion;1 and that finally he went to
Geneva, where, if he was not recalled to the
Protestant faith, he was at least most thorough¬
ly reclaimed from the errors of Popery.2
To these early fluctuations in his religious
creed, may be ascribed his singularly accurate
knowledge of controversial theology, and of the
lives and tenets of the most distinguished divines
of both churches;—a knowledge much more
minute than a person of his talents could well be
supposed to accumulate from the mere impulse
of literary curiosity. In these respects he ex¬
hibits a striking resemblance to the historian of
the Decline and Fall of the Boman Empire: Nor
is the parallel between them less exact in the
similar effects produced on their minds, by the
polemical cast of their juvenile studies. Their
common propensity to indulge in indecency is
not so easily explicable. In neither does it seem
to have originated in the habits of a dissolute
youth; but in the wantonness of a polluted and
distempered imagination. Bayle, it is well
known, led the life of an anchoret ;3 and the li¬
centiousness of his pen is, on that very account,
the more reprehensible. But, everything con¬
sidered, the grossness of Gibbon is certainly the
more unaccountable, and perhaps the more un¬
pardonable of the two.4
1 “ For the benefit of education, the Protestants were tempted to risk their children in the Catholic Universities ; and
in the 22d year of his age young Bayle was seduced by the arts and arguments of the Jesuits of Ihoulouse. Pie remained
about seventeen months in their hands a voluntary captive.”—(Gibbon’s Misc. Works, Yol. I. p. 49.) .
2 According to Gibbon, “ the piety of Bayle was offended by the excessive worship of creatures ; and the study of physics
convinced him of the impossibility of transubstantiation, which is abundantly refuted by the testimony of our senses.
The^same author, speaking of his own conversion from Popery, observes (after allowing to his Preceptor Mr Pavillard
“ a handsome share” of the honour), “ that it was principally effected by his private reflectionsadding the following
very curious acknowledgment: “ I still remember my solitary transport at the discovery of a philosophical argument against
the doctrine of Transubstantiation; that the text of Scripture, which sesms to inculcate the real presence, is attested only
by a single sense—our sight; while the real presence itself is disproved by three of our senses—the sight, the touch, and
the taste.”—(Ibid. p. 58.) That this '■'■philosophical argument” should have had any influence on the mind or Gibbon, even
at the early period of life when he made “ the discovery,” would appear highly improbable, if the fact were not attested
by himself; but as for Bayle, whose logical acumen was of a far harder and keener edge, it seems quite impossible to con¬
ceive, “ that the study of physics” was at all necessary to open his eyes to the absurdity of the real presence^; or that he
would not at once have perceived the futility of appealing to our senses or to our reason, against an article of faith which
professedly disclaims the authority of both. ' _ v .
3 “ Chaste dans ses discours, grave dans ses discours, sobre dans ses alimens, austere dans son genre de vie. (1 ortrait
de Bayle par M. Saurin, dans son Sermop sur Paccord de la Religion avec la Politique.) _ ....
4 In justice to Bayle, and also to Gibbon, it should be remembered, that over the most offensive passages in their works
they have drawn the veil of the learned languages. It was reserved for the translators of the Historical and Critical Dic¬
tionary to tear this veil asunder, and to expose the indelicacy of their author to every curious eye. It is impossible to ob¬
serve the patient industry and fidelity with which they have executed this part of their task without feelings of indignation
and disgust. For such an outrage on taste and decorum, their tedious and feeble attacks on the Manicheism of Bayle offer
but a poor compensation. Of all Bayle’s suspected heresies, it was perhaps that which stood the least in need of a serious
refutation; and, if the case had been otherwise, their incompetency to contend with such an adversary would have only
injured the cause which they professed to defend.
DISSERTATION FIRST.
155
On the mischievous tendency of Bayle’s work
to unsettle the principles of superficial readers,
and, what is worse, to damp the moral enthusi¬
asm of youth, by shaking their faith in the re¬
ality of virtue, it would be superfluous to enlarge.
The fact is indisputable, and is admitted even by
his most partial admirers. It may not he equally
useless to remark the benefits which (whether
foreseen or not by the author, is of little conse¬
quence) have actually resulted to literature from
his indefatigable labours. One thing will, I ap¬
prehend, be very generally granted in his favour,
that, if he has taught men to suspend their judg¬
ment, he has taught them also to think and to
reason for themselves; a lesson which appeared
to a late philosophical divine of so great impor¬
tance, as to suggest to him a doubt, whether it
would not be better for authors to state nothing
but premises, and to leave to tbeir readers the
task of forming their own conclusions.1 Nor
can Bayle be candidly accused of often discover¬
ing a partiality for any particular sect of philo¬
sophers. He opposes Spinoza and Hobbes with
the same spirit and ability, and apparently with
the same good faith, with which he controverts
the doctrines of Anaxagoras and of Plato.
Even the ancient sceptics, for whose mode of
philosophising he might be supposed to have felt
some degree of tenderness, are treated with as
little ceremony as the most extravagant of the
dogmatists. He has been often accused of a
leaning to the most absurd of all systems, that
of the Manicheans; and it must be owned, that
there is none in defence of which he has so often
and so ably2 * exerted his talents; but it is easy
to perceive, that, when he does so, it is not from
any serious faith which he attaches to it (per¬
haps the contrary supposition would be nearer
the truth), but from the peculiarly ample field
which it opened for the display of his contro¬
versial subtlety, and of his inexhaustible stores
of miscellaneous information.5 In one passage
he has pronounced with a tone of decision which
he seldom assumes, that “it is absurd, indefen¬
sible, and inconsistent with the regularity and
order of the universe; that the arguments in
favour of it are liable to be retorted; and that,
granting it to be true, it would afford no solu¬
tion of the difficulties in question.”4 The ap¬
parent zeal with which, on various occasions, he
has taken up its defence, may, I think, be reason¬
ably accounted for, by the favourable opportu¬
nity it afforded him of measuring his logical
powers with those of Leibnitz.5
To these considerations it may be added, that,
in consequence of the progress of the sciences
since Bayle’s time, the unlimited scepticism
commonly, and perhaps justly imputed to him,
is much less likely to mislead than it was a cen¬
tury ago; while the value of his researches, and
of his critical reflections, becomes every day
more conspicuous, in proportion as more en¬
larged views of nature, and of human affairs,
enable us to combine together that mass of
rich but indigested materials, in the compilation
of which his own opinions and principles seem
to have been totally lost. Neither comprehen¬
sion, indeed, nor generalisation, nor metaphysical
1 See the preface to Bishop Butler’s Sermons.
* Particularly in the article entitled Paulicians.
* One of the earliest as well as the ablest of those who undertook a reply to the passages in Bayle which seem to favour
Manicheism, candidly acquits him of any serious design to recommend that system to his readers. “ En repondant aux
objections Manicheennes, je ne pretends faire aucun tort k M. Bayle : que je ne soup^onne nullement de les favoriser. Je
suis persuade qu’il n’a pris la liberte philosophique de dire, en bien des rencontres, le pour et le contre, sans ritn dissimu-
ler, que pour donner de I’exercice a ceux qui entendent les matieres qu’il traite, et non pour favoriser ceux dont il explique
les raisons.”—(Parrhasiana, ou Pense.es inverses, p. 302, par M. Le Ci.eiic. Amsterdam, 1699.)
4 See the illustration upon the Sceptics at the end of the Dictionary.
‘ This supposition may be thought inconsistent with the well known fact, that the Theodicee of Leibnitz was not pub¬
lished till after the death of Bayle. But it must be recollected, that Bayle had previously entered the lists with Leibnitz
in the article Rorarius, where he had urged some very acute and forcible objections against the scheme nipre-estabVished har¬
mony; a scheme which leads so naturally and obviously to that of optimism, that.it was not difficult to foresee what ground
Leibnitz was likely to take in defending his principles. The great aim of Bayle seems to have been to provoke Leibnitz
to unfold the whole of his system and of its necessary consequences ; well knowing what advantages in the management of
such a controversy would be on the side of the assailant.
The tribute paid by Leibnitz to the memory of his illustrious antagonist deserves to be quoted. “ Sperandum est,
Bcelium luminibus illis nunc circumdari, quod terris negatum est: cum credibile sit, bonam voluntatem ei nequaquam
defuisse.”
“ Candidus insuetum miratur limen CLympi,
Sub pedibusque videt nubes et sidera Daphnis. ”
156
PRELIMINARY DISSERTATIONS.
depth,1 are to be numbered among the charac-
teristical attributes of his genius. Far less does
he ever anticipate, by the moral lights of the
soul, the slow and hesitating decisions of the un¬
derstanding; or touch with a privileged hand
those mysterious chords to which all the social
sympathies of our frame are responsive. Had
his ambition, however, been more exalted, or his
philanthropy more warm and diffusive, he would
probably have attempted less than he actually
accomplished ; nor would he have stooped to en¬
joy that undisputed pre-eminence which the
public voice has now unanimously assigned him,
among those inestimable though often ill requit¬
ed authors, whom Johnson has called “ the
pioneers of literature.”
The suspense of judgment which Bayle’s
Dictionary inspires with respect to facts, is, per¬
haps, still more useful than that which it en¬
courages in matters of abstract reasoning. Fon-
tenelle certainly went much too far, when he
said of history, that it was only a collection of
Fables Convenues ;—a most significant and happy
phrase, to which I am sorry that I cannot do
justice in an English version. But though Fon-
tenelle pushed his maxim to an extreme, there
is yet a great deal of important truth in the re¬
mark ; and of this I believe every person’s con¬
viction will he stronger, in proportion as his
knowledge of men and of books is profound and
extensive.2
Of the various lessons of historical scepticism
to be learned from Bayle, there is none more
practically valuable (more especially in such
revolutionary times as we have witnessed) than
that which relates to the biographical portraits
of distinguished persons, when drawn by their
theological and political opponents. In illustra¬
tion of this, I have only to refer to the copious
and instructive extracts which he has produced
from Roman Catholic writers, concerning the
lives, and still more concerning the deaths, of
Luther, Knox,5 Buchanan, and various other
leaders or partizans of the Reformation. It
would be impossible for any well-informed Pro¬
testant to read these extracts, without indulging
a smile at their incredible absurdity, if every
feeling of levity were not lost in a sentiment of
deep indignation at the effrontery and falsehood
of their authors. In stating this observation, I
have taken my examples from Roman Catholic
libellers, without any illiberal prejudices against
the members of that church. The injustice done
by Protestants to some of the conscientious de¬
fenders of the old faith has been, in all probabi¬
lity, equally great; but this we have no oppor¬
tunity of ascertaining here, by the same direct
evidence to which we can fortunately appeal, in
vindication of the three characters mentioned
above. With the history of two of them every
person in this country is fully acquainted; and
I have purposely selected them in preference to
others, as their names alone are sufficient to cover
with disgrace the memory of their calumniators.4
A few years before the death of Bayle, Fon-
tenelle began to attract the notice of Europe.5
I class them together on account of the mighty
influence of both on the literary taste of their
contemporaries; an influence in neither case
founded on any claims to original genius, or to
important improvements; but on the attractions
which they possessed in common, though in
very different ways, as popular writers; and on
the easy and agreeable access which their works
opened to the opinions and speculations of the
* I speak of that metaphysical depth which is the exclusive result of what Newton called patient thinking. In logical
quickness, and .metaphysical subtlety, Bayle has never been surpassed.
2 M°nfes(luieu has expressed himself on this subject, in nearly as strong terms as Fontenelle. “ Les Histoires sent
des faits faux composes sur des fails vrais, ou bien al’occasion des vrais.”—(Pensees Diverses de Montesquieu, Tom. Y.
de ses CEuvres. Ed. de Paris, 1818.)
3 See Note Q.Q.
4 Of all Bayle’s works, “ the most useful and the least sceptical,” according to Gibbon, “ is his Commentaire Philoso-
phique on these words of the Gospel, Compel them to come in.”
The great object of this commentary is to establish the general principles of Toleration, and to remonstrate with the
members of Protestant churches on the inconsistency of their refusing to those they esteem heretics, the same indulgence
which they claim for themselves in Catholic countries. The work is diffuse and rambling, like all Bayle’s compositions •
but the matter is excellent, and well deserves the praise which Gibbon has bestowed on it.
£ Bayle died in 1708. .1 ontenelle’s first work in prose (the Dialogues of the Dead) was published as early as 1683 and
was quickly followed by his Conversations on the Plurality of Worlds.
i
DISSERTATION FIRST.
157
learned. Nor do I depart so far as might at
first he supposed, from the order of chronology,
in passing from the one to the other. For though
Fontenelle survived almost to our own times
(having very nearly completed a century at the
time of his death), the interval between his
birth and that of Bayle was only ten years, and
he had actually published several volumes, both
in prose and verse, before the Dictionary of Bayle
appeared.
But my chief reason for connecting Fonte¬
nelle rather with the contemporaries of his youth
than with those of his old age is, that, during
the latter part of his life, he was left far behind
in his philosophical creed (for he never renoun¬
ced his faith as a Cartesian)1 2 * * * by those very
pupils to whose minds he had given so power¬
ful an impulse, and whom he had so long taught
by his example, the art (till then unknown in
modern times) of blending the truths of the
severer sciences with the lights and graces of
eloquence. Even this eloquence^ once so much
admired, had ceased, before his death, to be re¬
garded as a model, and was fast giving way to
the purer and more manly taste in writing, re¬
commended by the precepts, and exemplified in
the historical compositions of Voltaire.
Fontenelle was a nephew of the great Cor¬
neille ; but his genius was, in many respects,
very strongly contrasted with that of the author
of the Cid. Of this he has himself enabled us
to judge by the feeble and unsuccessful attempts
in dramatic poetry, by which he was first known
to the world. In these, indeed, as in all his
productions, there is an abundance of ingenu¬
ity, of elegance, and of courtly refinement; but
not the faintest vestige of the mens divinior, or
of that sympathy with the higher and nobler
passions which enabled Corneille to re-animate
and to reproduce on the stage the heroes of an¬
cient Rome. The circumstance, however, which
more peculiarly marks and distinguishes his
writings, is the French mould in which education
and habit seem to have recast all the original
features of his mind;—identifying, at the same
time, so perfectly the impressions of art with the
workmanship of nature, that one would think
the Parisian, as well as the man, had started
fresh and finished from her creative hand. Even
in his Conversations on the Plurality of Worlds,
the dry discussions with the Marchioness about
the now forgotten vortices of Descartes, are en¬
livened throughout by a never-failing spirit of
light and national gallantry, which will for ever
render them an amusing picture of the manners of
the times, and of the character of the author. The
gallantry, it must be owned, is often strained
and affected; but the affectation sits so well on
Fontenelle, that he would appear less easy and
graceful without it.
The only other production of Fontenelle’s
youth which deserves to be noticed is his History
of Oracles; a work of which the aim was, to
combat the popular belief that the oracles of an¬
tiquity were uttered by evil spirits, and that all
these spirits became dumb at the moment of the
Christian eera. To this work Fontenelle con¬
tributed little more than the agreeable and live¬
ly form in which he gave it to the world; the
chief materials being derived from a dull and
prolix dissertation on the same subject, by a
learned Dutchman. The publication excited a
keen opposition among divines, both Catholic
and Protestant; and, in particular, gave occa¬
sion to a very angry, and, it is said, not con¬
temptible criticism, from a member of the So¬
ciety of Jesuits.8 It is mentioned by La Harpe,
as an illustration of the rapid change in men’s
1 Excepting on a few metaphysical points. The chief of these were, the question concerning the origin of our ideas,
and that relating to the nature of the lower animals. On the former of these subjects he has said explicitly: “ L An-
cienne Philosophic n’a pas toujours eu tort. Elle a soutenu que tout ce qui etoit dans Pesprit avoit passe, par les sens, et
nous n’aurions pas mal fait de conserver cela d’elle.”—(Fragment of an intended Treatise on the Human Mind.) On another
occasion, he states his own opinion on this point, in language coinciding exactly with that of Gassendi. . “ A force d operer
sur les premieres idees formees par les sens, d’y ajouter, d’en retrancher, de les rendre de particulieresuniverselles, d univer-
selles plus universelles encore, 1’esprit les rend si differentesde ce qu’elles dtoient d’abord qu’on a quelquefois peine a recon¬
noitre leur origine. Cependant qui voudra prendre le fil et le suivre exactement, retournera toujours de 1 idee la plus
sublime et la plus dlevee, a quelque ide'e sensible et grossiere.” >
2 To this criticism, the only reply made by Eontenelle was a single sentence, which he addressed to a Journalist who
had urged him to take up arms in his own defence. “ Je laisserai mon censeur jouir en paix de son triomphe; je consens
que le diable ait dtd prophete, puisque le Jesuite le veut, et qu’il croit cela plus orthodoxe.”—(D’A i. e m n e ux, Eloge tle^ la
Matte. J We are told by D’Alembert, that the silence of Fontenelle, on this occasion, was owing to the advice ot Da
158
PRELIMINARY DISSERTATIONS.
opinions which took place during Fontenelle’s
life, that a book which, in his youth, was cen¬
sured for its impiety, was regarded before his
death as a proof of his respect for religion.
The most solid basis of Fontenelle’s fame is
his History of the Academy of Sciences, and his
Eloges of the Academicians. Both of these works,
but more especially the latter, possess, in an
eminent degree, all the charms of his former
publications, and are written in a much simpler
and better taste than any of the others. The
materials, besides, are of inestimable value, as
succinct and authentic records of one of the most
memorable periods in the history of the human
mind; and are distinguished by a rare imparti¬
ality towards the illustrious dead, of all coun¬
tries, and of all persuasions. The philosophi¬
cal reflections, too, which the author has most
skilfully interwoven with his literary details,
discover a depth and justness of understanding
far beyond the promise of his juvenile Essays;
and afford many proofs of the soundness of his
logical views,1 as well as of his acute and fine
discrimination of the varieties and shades of
character, both intellectual and moral.
The chief and distinguishing merit of Fonte-
nelle, as the historian of the Academy, is the
happy facility with which he adapts the most
abstruse and refined speculations to the compre¬
hension of ordinary readers. Nor is this excel¬
lence purchased by any sacrifice of scientific
precision. What he aims at is nothing more
than an outline; but this outline is always exe¬
cuted with the firm and exact hand of a master.
“ When employed in composition (he has some¬
where said) my first concern is to be certain
that I myself understand what I am about to
writeand on the utility of this practice every
page of his Historical Memoirs may serve as a
comment.2
As a writer of Eloges, he has not been equal¬
led (if I may be allowed to hazard my own opi¬
nion) by any of his countrymen. Some of those,
indeed, by D’Alembert and by Condorcet, ma¬
nifest powers of a far higher order than belonged
to Fontenelle; but neither of these writers pos¬
sessed Fontenelle’s incommunicable art of in¬
teresting the curiosity and the feelings of his
readers in the fortunes of every individual whom
he honoured by his notice. In this art it is not
improbable that they might have succeeded bet¬
ter had they imitated Fontenelle’s self-denial in
sacrificing the fleeting praise of brilliant colour¬
ing, to the fidelity and lasting effect of their
portraits; a self-denial which in him was the
more meritorious, as his great ambition plainly
was to unite the reputation of a hel-esprit with
that of a philosopher. A justly celebrated aca¬
demician of the present times (M. Cuvier), who
has evidently adopted Fontenelle as his model,
has accordingly given an interest and truth to
his Eloges, which the public had long ceased to
expect in that species of composition.3
But the principal charm of Fontenelle’s Eloges
Motte. “ Fontenelle bien tente de terrasser son adversaire par la facilite qu’il y trouvoit, fut retenu par les avis prudens
de La Motte; cet ami lui fit craindre de s’alie'ner par sa reponse une societe qui s’appeloit Legion, quand on avoit affaire au
dernier de ses membres.” The advice merits the attention of philosophers in all countries, for the spirit of Jesuitism is not
confined to the Church of Home.
1 An instance of this which happens at present to recur to my memory, may serve to illustrate and to confirm the above
remark. It is unnecessar}' to point out its coincidence with the views which gave birth to the new nomenclature in
chemistry.
“ If languages had been the work of philosophers, they might certainly be more easily learned. Philosophers would
have established everywhere a systematical uniformity, which would have proved a safe and infallible guide ; and the man-
ner of forming a derivative word, would, as a necessary consequence, have suggested its signification. The uncivilised
nations, who are the first authors of languages, fell naturally into that notion with respect to certain terminaiions, all of
which have some common property or virtue; but that advantage, unknown to those who had it in their hands, was not
carried to a sufficient extent.”
* From this praise, however, must be excepted, the mysterious jargon in which (after the example of some of his con¬
temporaries) he has indulged himself in speaking of the geometry and calculus of infinites. “ Nous le disons avec peine
(says D’Alembert), et sans vouloir outrager les manes d’un homme cdlebre qui n’est plus, il n’y a peut-etre point d’ouvrage
oil Ton trouye des preuves plus frdquentes de Tabus de la metaphysique, que dans Touvrage tres connu de M. Fontenelle,
qui a pour litre Elemens de la Geometric de Vlnfini ; ouvrage dont la lecture est d’autant plus dangereuse aux jeunes geo¬
metres que Tauteur y prdsente les sophismes avec une sorte d’dlegance et de grace, dont le sujet ne paroissoit pas suscep¬
tible.”—{Melanges, &c. Tom. Y. p. 264.)
a D’Alembert, in his ingenious parallel of Fontenelle and La Motte, has made a remark on Fontenelle’s style when he
aims at simplicity, of the justness of which French critics alone are competent judges. “ L’un et Tautre ont dcrit en prose
avec beaucoup de clarte, d’dlegance, de simplicitd meme ; mais La Motte avec une simplicite plus naturelle, et Fontenelle
DISSERTATION FIRST.
159
aiises rrom the pleasing pictures which they
everywhere present of genius and learning in
the scenes of domestic life. In this respect, it
has been justly said of them by M. Suard,1 that
“ they form the noblest monument ever raised
to the glory of the sciences and of letters.” Fon-
tenelle himself, in his Eloge of Vorignon, after
remarking, that in him the simplicity of his cha¬
racter was only equalled by the superiority of
his talents, finely adds, “ I have already be¬
stowed so often the same praise on other mem¬
bers of this academy, that it may be doubted
whether it is not less due to the indi viduals, than
to the sciences which they cultivated in com¬
mon.” What a proud reply does this reflection
afford to the Machiavellian calumniators of phi¬
losophy ! **
The influence of these twm works of Fon-
tenelle on the studies of the rising generation all
over Europe, can be conceived by those alone
who have compared them with similar produc¬
tions of an earlier date. Sciences which had
long been immured in colleges and cloisters,
began at length to breathe the ventilated and
wholesome air of social life. The union of phi¬
losophy and the fine arts, so much boasted of in
the schools of ancient Greece, seemed to promise
a speedy and invigorated revival. Geometry,
Mechanics, Physics, Metaphysics, and Morals,
became objects of pursuit in courts and in camps ;
the accomplishments of a scholar grew more and
more into repute among the other characteristics
of a gentleman : and (what was of still greater
importance to the world) the learned discovered
the secret of cultivating the graces of writing,
as a necessary passport to truth, in a refined but
dissipated age.
Nor was this change of manners confined to
one of the sexes. The other sex, to whom na¬
ture has entrusted the first development of our
intellectual and moral powers, and who may,
therefore, be regarded as the chief medium
through which the progress of the mind is con¬
tinued from generation to generation, shared also
largely in the general improvement. Fontenelle
aspired above all things to be the philosopher of
the Parisian circles; and certainly contributed
not a little to diffuse a taste for useful know¬
ledge among women of all conditions in France,
by bringing it into vogue among the higher
classes. A reformation so great and so sudden
could not possibly take place, without giving
birth to much affectation, extravagance, and
folly; but the whole analogy of human affairs
encourages us to hope, that the inconveniencies
and evils connected with it will be partial and
temporary, and its beneficial results permanent
and progressive.2
Among the various moral defects imputed to
Fontenelle, that of a complete apathy and in-
avec une simplicity plus ytudi^e: car la simplicity peut Petre, et des lors elle devient maniere, et cesse d’etre modele.”
An idea very similar to this is happily expressed by Congreve, in his portrait of Amoret:
Coquet and Coy at once her air,
Both studied, though both seem neglected:
Careless she is with artful care.
Affecting to seem unaffected.
1 Notice sur la Vie et les Ecrits du Docteur Robertson. (Paris, lb 17-)
! Among the various other respects in which Fontenelle contributed to the intellectual improvement of his countrymen,
it ought to be mentioned, that he was one of the first writers in France who diverted the at tention of metaphysicians from
the old topics of scholastic discussion, to a philosophical investigation of the principles of the fine arts. Various original
hints upon these subjects are scattered over his works: but the most favourable specimens of his talents for this very delicate
species of analysis are to be found in his Dissertation on Pastorals, and in his Theory concerning the Delight we derive from
Tragedy.* His speculations, indeed, are not always just and satisfactory; but they are seldom deficient in novelty or re¬
finement. Their principal fault, perhaps, arises from the author’s disposition to carry his refinements too far; in con¬
sequence of which, his theories become chargeable with that sort of sublimated ingenuity which the French epithet Alambique
expresses more precisely and forcibly than any word in our language.
Something of the same philosophical spirit may be traced in Fenelon’s Dialogues on Eloquence, and in his Letter on
Rhetoric and Poetry. The former of these treatises, besides its merits as a speculative discussion, contains various prac¬
tical hints, well entitled to the attention of those who aspire to eminence as public speakers; and of which the most
apparently trifling claim some regard, as the results of the author’s reflections upon an art which few ever practised with
greater success.
Let me add, that both of these eminent men (who may be regarded as the fathers of philosophical criticism in France)
were zealous partizans and admirers of the Cartesian metaphysics. It is this critical branch of metaphysical science which,
* In the judgment of Mr Hume, “ there is not a finer piece of criticism than Fontenelle’s Dissertation on Pastorals; in
which, by a number of reflections and philosophical reasonings, he endeavours to fix the just medium between simplicity
and refinement, which is suitable to that species of poetry.”
160
PRELIMINARY DISSERTATIONS.
sensibility to all concerns but his own is by far
the most prominent. A letter of the Baron de
Grimm, written immediately after Fontenelle s
death, but not published till lately, has given a
new circulation in this country to some anec¬
dotes injurious to bis memory, which had long
ago fallen into oblivion or contempt in France.
The authority, however, of this adventurer, who
earned his subsistence by collecting and retail¬
ing, for the amusement of a German Prince,
the literary scandal of Paris, is not much to be
relied on in estimating a character with which
he does not appear to have had any opportunity of
becoming personally acquainted; more especially
as, during Fontenelle’s long decline, the great
majority of men of letters in France were dis¬
posed to throw his merits into the shade, as
an acceptable homage to the rising and more
dazzling glories of Voltaire.1 It is in the Aca¬
demical Memoirs of D’Alembert and Condorcet
(neither of whom can be suspected of any un¬
just prejudice against Voltaire, but who were
both too candid to sacrifice truth to party feel¬
ings) that we ought to search for Fontenelle’s
real portrait:8 Or rather (if it be true, as
Dr Hutcheson has somewhere remarked, that
“ men have commonly the good or bad quali¬
ties which they ascribe to mankind”) the most
faithful Eloge on Fontenelle himself is to be
found in those which he has pronounced upon
others.
That the character of Fontenellc would have
been more amiable and interesting, had his vir¬
tues been less the result of cold and prudent
calculation, it is impossible to dispute. But his
conduct through life was pure and blameless;
and the happy serenity of his temper, which
prolonged his life till he had almost completed
his hundredth year, served as the best comment
on the spirit of that mild and benevolent philo¬
sophy, of which he had laboured so long to ex¬
tend the empire.
It is a circumstance almost singular in his
history, that since the period of Ijlis death, his
reputation, both as a man and as an author,
has been gradually rising. The fact has been
as remarkably the reverse with most of those
who have calumniated his memory.
While the circle of mental cultivation was
thus rapidly widening in France, a similar pro¬
gress was taking place! upon a larger scale, and
under still more favourable circumstances, in
England. To this progress nothing contributed
in my opinion, has been most successfully cultivated by French writers; although too many of them have been infected
(after the example of Fontenelle) with the disease of sickly and of hyper-metaphysical subtlety.
From this censure, however, must be excepted the Abbe Dubos, whose Critical Reflections on Poetry and Painting is one
of the most agreeable and instructive works that can b@ put into the hands of youth. Few books are better calculated for
leading their minds gradually from literature to philosophy. The author’s theories, if not alway s profound or just, are in
general marked with good sense as well as with ingenuity; and the subjects to which they relate are so peculiarly^ attrac¬
tive, as to fix the attention even of those readers who have but little relish for speculative discussions. “ Ce qui fait la
bontdde cet ouvrage (says Voltaire) c’est qu’il n’y a que pen d’erreurs, et beaucoup de re'flexions vraies, nouvelles, et pro-
fondes. 11 manque cependant d’ordre et sur-tout de pre'cision ; il auroit pu etre e'crit avec plus de feu, de grace, et d’el£-
gance ; mats Vecrivain pense et fait penser."—(Siecle de Louis XIV.)
1 As to Voltaire himself, it must be mentioned, to his honour, that though there seems never to have been much cordia¬
lity between him and Fontenelle, he had yet the magnanimity to give a place to this Nestor of French literature in his
catalogue of the eminent persons who adorned the reign of Louis XIV.: a tribute of respect the more flattering, as it is
the single instance in which he has departed from his general rule of excluding from his list the names of all his living con¬
temporaries. Even Fontenelle’s most devoted admirers ought to be satisfied with the liberality of Voltaire’s eulogy, in
which, after pronouncing Fontenelle “ the most universal genius which the age of Louis XIV. had produced,” he thus sums
up his merits as an author. “ Enfin on 1’a regarde; comme le premier des hommes dans 1’art nouveau de repandre de la
lumiere et des graces sur les sciences abstraites, et il a eu du merite dans tous les autres genres qu’il a traites. 'iantde
talens ont ete soutenus par la connoissance des langues et de 1’histoire, et il a tie sans contredit au-dessus de tous les sgavans qui
n'ont pas eu le don de Vinvention."
* Condorcet has said expressly, that his apathy was confined entirely to what regarded himself; and that he was always
an active, though frequently a concealed friend, where his good offices could be useful to those who deserved them. “ On a
cru Fontenelle insensible, parce que sachant miiitriser les mouvemens de son ame il se conduisoit d’apres son esprit, toujours
juste et toujours sage. D’ailleurs, il avoit consenti sans peine a conserver cette reputation d’insensibilite; il avoit souffert
les plaisanteries de ses societe's sur sa froideur, sans chercher a les de'tromper, parce que, bien sur que les vraies amis n’en
seroit pas la dupe, il voyoit dans cette reputation un moyen commode de se delivrer des indifferens sans blesser leur amour-
propre.” (Eloge de Fontenelle, par Condorcet.)
Many of Fontenelle’s sayings, the import of which must have depended entirely on circumstances of time and place un¬
known to us, have been absurdly quoted to his disadvantage, in their literal and most obvious acceptation. “ I hate war
(said he), for it spoils conversation.” Can any just inference be drawn from the levity of this convivial sally, against the
humanity of the person who uttered it? Or rather, when connected with the characteristical finesse of Fontenelle’s wit,
does it not lead to a conclusion precisely opposite ?
DISSERTATION FIRST.
161
more powerfully than the periodical papers pub¬
lished under various titles by Addison1 and his
associates. The effect of these in reclaiming
the public taste from the licentiousness and
grossness introduced into England at the period
of the Restoration ; in recommending the most
serious and important truths by the united at¬
tractions of wit, humour, imagination, and elo¬
quence ; and, above all, in counteracting those
superstitious terrors which the weak and igno¬
rant are so apt to mistake for religious and moral
impressions—has been remarked by numberless
critics, and is acknowledged even by those who
felt no undue partiality in favour of the authors.8
Some of the papers of Addison, however, are of
an order still higher, and bear marks of a mind
which, if early and steadily turned to philoso¬
phical pursuits, might have accomplished much
more than it ventured to undertake. His fre¬
quent references to the Essay on Human Under¬
standing, and the high encomiums with which
they are always accompanied, show how suc¬
cessfully he had entered into the spirit of that
work, and how completely he was aware of the
importance of its object. The popular nature
of his publications, indeed, which rendered it
necessary for him to avoid everything that
might savour of scholastic or of metaphysical
discussion, has left us no means of estimating
his philosophical depth, but what are afforded
by the results of his thoughts on the particular
topics which he has occasion to allude to, and
by some of his incidental comments on the
scientific merits of preceding authors. But
these means are sufficiently ample to justify a
very high opinion of his sound and unprejudiced
judgment, as well as of the extent and correct¬
ness of his literary information. Of his powers
as a logical reasoner he has not enabled us to
form an estimate; but none of his contempo¬
raries seem to have been more completely tinc¬
tured with all that is most valuable in the me¬
taphysical and ethical systems of his time.3
But what chiefly entitles the name of Addi¬
son to a place in this Discourse, is his Essays on
the Pleasures of Imagination ; the first attempt
in England to investigate the principles of the
fine arts ; and an attempt which, notwithstand¬
ing many defects in the execution, is entitled to
the praise of having struck out a new avenue to
the study of the human mind, more alluring
than any which had been opened before. In
this respect, it forms a most important supple¬
ment to Locke's Survey of the Intellectual Powers ;
and it has, accordingly, served as a text, on
which the greater part of Locke’s disciples have
been eager to offer their comments and their
corrections. The progress made by some of
these in exploring this interesting region has
been great; but let not Addison be defrauded of
his claims as a discoverer.
Similar remarks may be extended to the hints
suggested by Addison on Wit, on Humour, and
on the causes of Laughter. It cannot, indeed,
be said of him, that he exhausted any one of
these subjects; but he had at least the merit of
starting them as problems for the consideration
of philosophers ; nor would it be easy to name
among his successors, a single writer who has
made so important a step towards their solution,
as the original proposer.
The philosophy of the papers to which the fore¬
going observations refer, has been pronounced
to be slight and superficial, by a crowd of modern
metaphysicians, who were but ill entitled to erect
themselves into judges on such a question.4 The
singular simplicity and perspicuity of Addison’s
style have contributed much to the prevalence
1 Born in 1672, died in 1719- _ , „ c „
2 See Pope’s Imitations of Horace, Book II. Epistle I. “ Unhappy Dryden, &c. &c. f f .
3 I quote the following passage from Addison, not as a specimen of his metaphysical acumen, hut as a proof of his good
sense in divining and obviating a difficulty which I believe most persons will acknowledge occurred to themselves when
they first entered on metaphysical studies:— ... . , ;+ ;s
“ Although we divide the soul into several powers and faculties, there is no such division in the soul^; sincedf “
the whole soul that remembers, understands, wills, or imagines. Our manner of considering the ^Xt^rdsubiects of
will, imagination, and the like faculties, is for the better enabling us to express ourselves in^ch f st^2on obJirves;
speculation, not that there is any such division in the soul itself. In another part of the same p p , herself.”—
that “ what we call the faculties of the soul are only the different ways or modes in which the soul can exert
^ "For some important remarks on the words Powers and Faculties, as applied to the Mind, see Locke, B. II. Ch. xxi. § 20.
* See Note R It. x
DISS. I. PART II.
162
PRELIMINARY DISSERTATIONS.
of this prejudice. Eager for the instruction,
and unambitious of the admiration of the multi¬
tude, he everywhere studies to bring himself
down to their level; and even when he thinks
with the greatest originality, and writes with
the most inimitable felicity, so easily do we en¬
ter into the train of his ideas, that we can hard¬
ly persuade ourselves that we could not have
thought and written in the same manner. He
has somewhere said of “ fine writing,” that it
“ consists of sentiments which are natural, with¬
out being obvious and his definition has been
applauded by Hume, as at once concise and just.
Of the thing defined, his own periodical essays
exhibit the most perfect examples.
To this simplicity and perspicuity, the wide
circulation which his works have so long main¬
tained among all classes of readers, is in a great
measure to he ascribed. His periods are not
constructed, like those of Johnson, to cc elevate
and surprise,” by filling the ear and dazzling
the fancy; but we close his volumes with greater
reluctance, and return to the perusal of them with
far greater alacrity. Franklin, whose fugitive
publications on political topics have had so extra¬
ordinary an influence on public opinion, both in
the Old and New Worlds, tells us that his style in
writing was formed upon the model of Addison:
Nor do I know anything in the history of his
life which does more honour to his shrewdness
and sagacity. The copyist, indeed, did not pos¬
sess the gifted hand of his master,—Museo con-
tingens cuncta lepore ; hut such is the effect of
his plain and seemingly artless manner, that the
most profound conclusions of political economy
assume, in his hands, the appearance of indis¬
putable truths; and some of them, which had
been formerly confined to the speculative few,
are already current in every country of Europe,
as proverbial maxims.1
To touch, however slightly, on Addison’s
other merits, as a critic, as a wit, as a specula¬
tive politician, and, above all, as a moralist,
would lead me completely astray from my pre¬
sent object. It will not he equally foreign to it
to quote the two following short passages,
which, though not strictly metaphysical, are, both
of them, the result of metaphysical habits of
thinking, and hear a stronger resemblance than
anything I recollect among the wits of Queen
Anne’s reign, to the best philosophy of the pre¬
sent age. They approach, indeed, very nearly to
the philosophy of Turgot and of Smith.
“ Among other excellent arguments for the
immortality of the soul, there is one drawn from
the perpetual progress of the soul to its perfec¬
tion, without a possibility of ever arriving at it;
which is a hint that I do not remember to have
seen opened and improved by others who have
written on this subject, though it seems to me
to carry a great weight with it. A brute arrives
at a point of perfection that he can never pass.
In a few years he has all the endowments he is
capable of; and were he to live ten thousand
more, would he the same thing he is at present.
Were a human soul thus at a stand in her ac¬
complishments, were her faculties to be full¬
blown, and incapable of further enlargement, I
would imagine it might fall away insensibly,
and drop at once into a state of annihilation.
But can we believe a thinking being, that is in
a perpetual progress of improvement, and tra¬
velling on from perfection to perfection, after
having just looked abroad into the works of its
Creator, and made a few discoveries of his in¬
finite goodness, wisdom, and power, must perish
at her first setting out, and in the very begin¬
ning of her inquiries ?”2
The philosophy of the other passage is not
unworthy of the author of the Wealth of Nations.
The thought may he traced to earlier writers, hut
certainly it was never before presented with the
same fulness and liveliness of illustration; nor
do I know, in all Addison’s works, a finer in¬
stance of his solicitude for the improvement of
his fair readers, than the address with which he
1 The expressions “ Laisscz^ nous fair e'' and pas trap gouvernerf which comprise, in a few words, two of the most im¬
portant lessons of Political Wisdom, are indebted chiefly for their extensive circulation to the short and luminous comments
of Franklin—(See his Political Fragments, § 4.)
2 This argument has been prosecuted with great ingenuity and force of reasoning (blended, however, with some of the
peculiarities of his Berkeleian metaphysics) by the late Dr James Hutton (See his Investigation of the Principles of Know.
ledge, Yol. III. p. 195, et seq. Edin. 1794.)
DISSERTATION FIRST.
163
nere insinuates one of the sublimest moral les¬
sons, while apparently aiming only to amuse
them with the geographical history of the muff
and the tippet.
“ Nature seems to have taken a particular
care to disseminate her blessings among the dif¬
ferent regions of the world, with an eye to the
mutual intercourse and traffic among mankind;
that the natives of the several parts of the globe
might have a kind of dependance upon one
another, and he united together by their com¬
mon interest. Almost every degree produces
something peculiar to it. The food often grows
in one country, and the sauce in another. The
fruits of Portugal are corrected by the products
of Barhadoes; the infusion of a China plant,
sweetened with the pith of an Indian cane. The
Philippine Islands give a flavour to our Euro¬
pean bowls. The single dress of a woman of
quality is often the product of a hundred cli¬
mates. The muff and the fan come together from
the opposite ends of the earth. The scarf is
sent from the torrid zone, and the tippet from
beneath the pole. The brocade petticoat rises
out of the mines of Peru, and the diamond neck¬
lace out of the bowels of Indostan.”
But I must not dwell longer on the fascinat¬
ing pages of Addison. Allow me only, before
I close them, to contrast the last extract with a
remark of Voltaire, which, shallow and con¬
temptible as it is, occurs more than once, both
in verse and in prose, in his voluminous writings.
II muril, k Moka, dans le sable Arabique,
Ce Caffe' ne'cessaire aux pays des frimats ;
II met la Fievre en nos climats,
Et le remede en Amerique.
(Epitre au Hoi du Prusse, 1750.)
And yet Voltaire is admired as a philosopher
by many who will smile to hear this title bestow¬
ed upon Addison !
It is observed by Akenside, in one of the notes
to the Pleasures of Imagination, that c< Philoso¬
phy and the Fine Arts can hardly be conceiv¬
ed at a greater distance from each other than at
the Revolution, when Locke stood at the head
of one party, and Dryden of the other.” He
observes, also, that “ a very great progress to¬
wards their re-union had been made within these
few years.” To this progress the chief impxdse was
undoubtedly given by Addison and Shaftesbury.
Notwithstanding, however, my strong parti¬
ality for the former of these writers, I should
be truly sorry to think, with Mr Hume, that
{C Addison will be read with pleasure when
Locke shall be entirely forgotten.”—(Essay on
the Differ'ent Species of Philosophy.)
A few years before the commencement of
these periodical works, a memorable accession
was made to metaphysical science, by the pub¬
lication of Berkeley’s New Theory of Vision, and
of his Principles of Human Knowledge. Possess¬
ed of a mind which, however inferior to that
of Locke in depth of reflection and in soundness
of judgment, was fully its equal in logical acute¬
ness and invention, and in learning, fancy, and
taste, far its superior,—Berkeley was singularly
fitted to promote that re-union of Philosophy and
of the Fine Arts which is so essential to the
prosperity of both. Locke, we are told, despis¬
ed poetry; and we know from one of his own
letters, that, among our English poets, his fa¬
vourite author was Sir Richard Blackmore.
Berkeley, on the other hand, courted the society
of all, from whose conversation and manners
he could hope to add to the embellishments of
his genius; and although himself a decided and
High Church Tory,1 lived in habits of friend¬
ship with Steele and Addison, as well as with
Pope and Swift. Pope’s admiration of him
seems to have risen to a sort of enthusiasm. He
yielded to Berkeley’s decision on a very delicate
question relating to the exordium of the Essay
on Man; and on his moral qualities he has be¬
stowed the highest and most unqualified eulogy
to be found in his writings.
, 1 See a volume of Sermons, preached in the chapel of Trinity College, Dublin. See also a Discourse addressed to Ma¬
gistrates, &c. printed in 1736. In both of these publications, the author carries his Tory principles so far, as to represent
the doctrine of passive obedience and non-resistance as an essential article of the Christian faith. “ The Christian religion
makes every legal constitution sacred, by commanding our submission thereto. Let every soul be subject to the higher powers,
saith St Paul, for the powers that be are ordained of God."
164
PRELIMINARY DISSERTATIONS.
“ Even in a Bishop I can spy desert;
Seeker is decent; Bundle has a heart;
Manners with candour are to Benson given;
To Berkeley every virtue under Heaven.”
With these intellectual and moral endow¬
ments, admired and blazoned as they were by
the most distinguished wits of his age, it is not
surprising that Berkeley should have given a
popularity and fashion to metaphysical pursuits,
which they had never before acquired in Eng¬
land. Nor was this popularity diminished by
the boldness of some of his paradoxes : on the
contrary, it was in no small degree the effect of
them; the great bulk of mankind being always
prone to mistake a singularity or eccentricity of
thinking, for the originality of a creative genius.
The solid additions, however, made by Berke¬
ley to the stock of human knowledge were im¬
portant and brilliant. Among these, the first
place is unquestionably due to his New Theory
of Vision ; a work abounding with ideas so dif¬
ferent from those commonly received, and, at
the same time, so profound and refined, that it
was regarded by all hut a few accustomed to deep
metaphysical reflection, rather in the light of a
philosophical romance, than of a sober inquiry
after truth. Such, however, has been since the
progress and diffusion of this sort of knowledge,
that the leading and most abstracted doctrines
contained in it, form now an essential part of
every elementary treatise of optics, and are
adopted by the most superficial smatterers in
science as fundamental articles of their faith.
Of a theory, the outlines of which cannot fail
to be familiar to a great majority of my readers,
it would he wholly superfluous to attempt any
explanation here, even if it were consistent with
the limits within which I am circumscribed.
Suffice it to observe, that its chief aim is to dis¬
tinguish the immediate and natural objects of
sight from the seemingly instantaneous conclu¬
sions which experience and habit teach us to
draw from them in our earliest infancy; or, in
the more concise metaphysical language of a
later period, to draw the line between the ori¬
ginal and the acquired perceptions of the eye.
They who wish to study it in detail, will find
ample satisfaction, and, if they have any relish
for such studies, an inexhaustible fund of enter¬
tainment, in Berkeley’s own short hut masterly
exposition of his principles, and in the excellent
comments upon it by Smith of Cambridge; by
Porterfield; by Beid; and, still more lately, by
the author of the Wealth of Nations.1
That this doctrine, with respect to the acquir¬
ed perceptions of sight, was quite unknown to
the best metaphysicians of antiquity, we have
direct evidence in a passage of Aristotle’s Nico-
machian Ethics, where he states the distinction
between those endowments which are the imme¬
diate gift of nature, and those which are the
fruit of custom and habit. In the former class,
he ranks the perceptions of sense, mentioning
particularly the senses of seeing and of hearing.
The passage (which I have transcribed in a
Note) is curious, and seems to me decisive on
the subject.2
The misapprehensions of the ancients on this
very obscure question will not appear surprising,
when it is considered, that forty years after the
publication of Berkeley’s Theory of Vision, and
sixty years after the date of Locke’s Essay, the
subject was so imperfectly understood in France,
that Condillac (who is, to this day, very gene¬
rally regarded by his countrymen as the father
of genuine logic and metaphysics) combated at
great length the conclusions of the English phi¬
losophers concerning the acquired perceptions of
sight; affirming that “ the eye judges naturally
of figures, of magnitudes, of situations, and of
1 By this excellent judge, Berkeley’s New Theory of Vision is pronounced to be “ one of the finest examples of Philoso¬
phical Analysis that is to be found in our own, or any other language.”—(Essays on Philosophical Subjects. Lond. 1795,
p. 215.)
2 Ob ya.Q \k rS •ttoXXockis r troXkdzis dasvirai ra; aurO'/urei; iXalioy.it, aXX’ ataTtaXit, i%ovris a %gn/raf/,itoi i%optv.
(Ethic. Nicomach. Lib. ii. cap. 1.)
“ For it is not from seeing often, or from hearing often, that we get these senses; but, on the contrary, instead of get¬
ting them by using them, we use them because we have got them.”
Had Aristotle been at all aware of the distinction so finely illustrated by Berkeley, instead of appealing to the percep¬
tions of these two senses, as instances of endowments coeval with our birth, he would have quoted them as the most
striking of all examples of the effects of custom in apparently identifying our acquired powers with our original faculties.
DISSERTATION FIRST.
165
distances.” His argument in support of this
opinion is to be found in the sixth section of
his Essay on the Origin of Human Knowledge.
It is difficult to suppose, that a person of
mature years, who had read and studied Locke
and Berkeley with as much care and attention
as Condillac appears to have bestowed on them,
should have reverted to this ancient and vulgar
prejudice; without suspecting that his metaphy¬
sical depth has been somewhat overrated by the
world.1 It is but justice, however, to Condillac
to add, that, in a subsequent work, he had the
candour to acknowledge and to retract his er¬
ror ;—a rare example of that disinterested love
of truth, which is so becoming in a philosopher.
I quote the passage (in a literal, though some¬
what abridged version), not only to show, that,
in the above statement, I have not misrepre¬
sented his opinion, hut because I consider this
remarkable circumstance in his literary history
as a peculiarly amiable and honourable trait in
his character.
“ We cannot recall to our memory the igno¬
rance in which we were born : It is a state
which leaves no trace behind it. We only re¬
collect our ignorance of those things, the know¬
ledge of which we recollect to have acquired;
and to remark what we acquire, some previous
knowledge is necessary. That memory which
now renders us so sensible of the step from one
acquisition to another, cannot remount to the
first steps of the progress; on the contrary, it
supposes them already made; and hence the
origin of our disposition to believe them‘connate
with ourselves. To say that we have learnt to
see, to hear, to taste, to smell, to touch, appears
a most extraordinary paradox. It seems to us
that nature gave us the complete use of our
senses the moment she formed them, and that
we have always made use of them without study,
because we are no longer obliged to study in
order to use them. I retained these prejudices
at the time I published my Essay on the Origin
of Human Knowledge ; the reasonings of Locke
on a man horn blind, to whom the sense of sight
was afterwards given, did not undeceive me :
and I maintained against this philosopher that the
eye judges naturally of figures, of sizes, of situa¬
tions, and of distances^—Nothing short of his
own explicit avowal could have convinced me,
that a writer of so high pretensions and of such
unquestionable ingenuity as Condillac, had real¬
ly commenced his metaphysical career under so
gross and unaccountable a delusion.
In bestowing the praise of originality on
Berkeley’s Theory of Vision, I do not mean to
say, that the whole merit of this Theory is ex¬
clusively his own. In this, as in most other
cases, it may be presumed, that the progress of
the human mind has been gradual : And, in
point of fact, it will, on examination, be found,
that Berkeley only took up the inquiry where
Locke dropped it; following out his principles
to their remoter consequences, and placing them
in so great a variety of strong and happy lights,
as to bring a doctrine till then understood but by
a few, within the reach of every intelligent and
attentive reader. For my own part, on com¬
paring these two philosophers together, I am at
a loss whether most to admire the powerful and
penetrating sagacity of the one, or the fertility
of invention displayed in the illustrations of the
other. What can be more clear and forcible
than the statement of Locke quoted in the Note
below; and what an idea does it convey of his
superiority to Condillac, when it is considered,
that he anticipated d priori the same doctrine
which was afterwards confirmed by the fine
analysis of Berkeley, and demonstrated by the
judicious experiments of Cheselden; while the
1 Voltaire, at an earlier period, had seized completely the scope of Berkeley’s theory ; and had explained it with equal
brevity and precision, in the following passage of his Elements of the Newtonian Philosophy:—
“ II faut absolument conclure, que les distances, les grandeurs, les situations ne sont pas, a proprement parler, des choses
visibles, c’est a dire, ne sont pas les objets propres et immediats de la vue. L’objet propre et immediat de la vue n’esi
autre chose que la lumiere coloree: tout le reste, nous ne le sentons qu’a la longue et par experience. Nous apprenons a
voir, precisement comme nous apprenons h parler et a lire. La difference est, que 1’art de voir est plus facile, et que la
nature est egalement h tous notre maitre.
“ Les jugemens soudains, presque uniformes, que toutes nos ames a un certain age portent des distances, des grandeurs,
des situations, nous font penser, qu’il n’y a qu’h. ouvrir les yeux pour voir la maniere dont nous voyons. On se trompe, il
y faut le secours des autres sens. Si les hommes n’avoient que le sens de la vue, ils n’auroient aucun moyen pour con-
noitre 1’etendue en longeur, largeur et profondeur, et un pur esprit ne la connoitroit peut-etre, a moins que Dieu ne la lui
rdve'lat.”—Phys. Newton, Chap. 7.
166
PRELIMINARY DISSERTATIONS.
French metaphysician, with all this accumula¬
tion of evidence before him, relapsed into a pre¬
judice transmitted to modern times, from the
very infancy of optical science !1
I believe it would he difficult to produce from
any writer prior to Locke, an equal number of im¬
portant facts relating to the intellectual phenome¬
na, as well observed, and as unexceptionahly de¬
scribed, as those which I have here brought under
my reader’s eye. It must appear evident, besides,
to all who have studied the subject, that Locke
has, in this passage, enunciated, in terms the
most precise and decided, the same general con¬
clusion concerning the effect of constant and
early habits, which it was the great object of
Berkeley’s Theory of Vision to establish, and
which, indeed, gives to that work its chief value,
when considered in connection with the Philo¬
sophy of the Human Mind.
Berkeley himself, it is to he observed, by no
means lays claim to that complete novelty in
his Theory of Vision, which has been ascribed
to it by many who, in all probability, derived
their whole information concerning it from the
traditional and inexact transcripts of book-mak¬
ing historians. In the introductory sentences
of his Essay, he states very clearly and candid¬
ly the conclusions of his immediate predecessors
on this class of our perceptions; and explains,
with the greatest precision, in what particulars
his own opinion differs from theirs. “ It is, I
think, agreed by all, that distance, of itself, can¬
not be seen. For distance being a line directed
end-wise to the eye, it projects only one point
in the fund of the eye, which point remains in¬
variably the same, whether the distance be
longer or shorter
“ I find it also acknowledged, that the esti¬
mate we make of the distance of objects consi¬
derably remote, is rather an act of judgment
grounded on experience, than of sense. For ex¬
ample, when I perceive a great number of inter¬
mediate objects, sucli as houses, fields, rivers,
and the like, which I have experienced to take
i “ We are farther to consider,” says Locke, “ concerning perception, that the ideas we receive by sensation are often in
grown people altered by the judgment, without our taking notice of it. When we set before our eyes a round globe, of any
uniform colour, v. g. gold, alabaster, or jet, it is certain that the idea thereby imprinted in our mind is of a flat circle, va¬
riously shadowed, with several degrees of light and brightness coming to our eyes. But we having by use been accustomed
to perceive what kind of appearance convex bodies are wont to make in us, what alterations are made in the reflections of
light by the difference of the sensible figure of bodies; the judgment presently, by an habitual custom, alters the appear¬
ances into their causes, so that, from what truly is variety of shadow or colour, collecting the figure it makes it pass for a
mark of figure, and frames to itself the perception of a convex figure, and an uniform colour ; when the idea we receive
from thence is only a plane variously coloured, as is evident in painting. * * * *
“ But this is not, I think, usual in any of our ideas, but those received by sight ;* because sight, the most comprehensive
of all our senses, conveying to our minds the ideas of lights and colours, which are peculiar only to that sense ; and also
the far different ideas of space, figure, or motion, the several varieties whereof change the appearances of its proper objects,
viz. light and colours, we bring ourselves by use to judge of the one by the other. This, in many cases, by a settled habit
in things whereof we have frequent experience, is performed so constantly and so quick, that we take that for the perception
of our sensation, which is an idea formed by our judgment; so that one, viz. that of sensation, serves only to excite the
other, and is scarce taken notice of itself: as a man who reads or hears with attention or understanding, takes little notice
of the characters or sounds, but of the ideas that are excited in him by them.
“Nor need we wonder that it is done with so little notice, if we consider how very quick the actions of the mind are pei-
formed; for as itself is thought to take up no space, to have no extension, so its actions seem to require no time, but many
of them seem to be crowded into an instant. I speak this in comparison to the actions of the body. Any one may easily
observe this in his own thoughts, who will take the pains to reflect on them. How, as it were in an instant, do our minds
with one glance see all the parts of a demonstration, which may very well be called a long one, if we consider the time it
will require to put it into words, and step by step show it to another ? Secondly, we shall not be so much surprised
that this is done in us with so little notice, if we consider how the facility which we get of doing things by a custom of doing
makes them often pass in us without our notice. Habits, especially such as are begun very early, come at last to produce
actions in us, which often escape our observations. How frequently do we in a day cover our eyes with our eye-lids, with
out perceiving that we are at all in the dark ? Men that have by custom got the use of a bye-word, do almost in every
sentence pronounce sounds, which, though taken notice of by others, they themselves neither hear nor observe; and, then?
fore, it is not so strange, that our mind should often change the idea of its sensation into that of its judgment, and make one
serve only to excite the other, without our taking notice of it.”—(Locke’s Works, Yol. I. p. 123, et seq.)
* Mr Locke might, however, have remarked something very similar to it in the perceptions of the ear; a very large pro¬
portion of its appropriate objects being rather judged of than actually perceived. In the rapidity (for example) of common
conversation, how many syllables, and even words, escape the notice of the most attentive hearer; which syllables and
words are so quickly supplied from the relation which they bear to the rest of the sentence, that it is quite impossible to dis¬
tinguish between the audible and the inaudible sounds ! A very palpable instance of this occurs in the difficulty expe¬
rienced by the most acute ear in catching proper names or arithmetical sums, or words borrowed from unknown tongues, the
first time they are pronounced.
DISSERTATION FIRST.
167
up a considerable space; I thence form a judg¬
ment or conclusion, that the object I see beyond
them is at a great distance. Again, when an
object appears faint and small, which, at a near
distance, I have experienced to make a vigorous
and large appearance, I instantly conclude it to
be far off. And this, ’tis evident, is the result
of experience, without which, from the faintness
and littleness, I should not have inferred any¬
thing concerning the distance of objects.
“ But when an object is placed at so near a
distance, as that the interval between the eyes
bears any sensible proportion to it, it is the re¬
ceived opinion that the two optic axes, concur¬
ring at the object, do there make an angle, by
means of which, according as it is greater or
less, the object is perceived to be nearer or far¬
ther off.
“ There is another way mentioned by the
optic writers, whereby they will have us judge
of those distances, in respect of which the
breadth of the pupil hath any sensible bigness;
and that is, the greater or less divergency of
the rays, which, issuing from the visible point,
do fall on the pupil; that point being judged
nearest, which is seen by most diverging rays,
and that remoter, which is seen by less diver¬
ging rays.”
These (according to Berkeley) are the “ com¬
mon and current accounts” given by mathema¬
ticians of our perceiving near distances by sight.
He then proceeds to show, that they are unsa¬
tisfactory ; and that it is necessary, for the so¬
lution of this problem, to avail ourselves of prin¬
ciples borrowed from a higher philosophy : Af¬
ter which, he explains, in detail, his own theory
concerning the ideas (sensations) which, by ex¬
perience, become signs of distance;1 2 * or (to use
his own phraseology) “ by which distance is
suggested* to the mind.” The result of the
whole is, that, “ a man boi-n blind, being made
to see, would not at first have any idea of dis¬
tance by sight. The sun and stars, the remotest
objects as well as the nearest, would all seem to be
in his Eye, or rather in his Mind.”*
From this quotation it appears, that, before
Berkeley’s time, philosophers had advanced
greatly beyond the point at which Aristotle
stopped, and towards which Condillac, in his first
publication, made a retrograde movement. Of
this progress some of the chief steps may be
traced as early as the twelfth century in the
Optics of Alhazen ;4 and they may be perceived
still more clearly and distinctly in various op¬
tical writers since the revival of letters; parti¬
cularly in the Optica Promota of James Gre¬
gory. 5 Father Malebranche went still farther,
and even anticipated some of the metaphysical
i \ Tn°r assi?ting persons unaccustomed to metaphysical studies to enter into the spirit and scope of Berkeley’s Theory, the
best illustration I know of is furnished by the phenomena of the Phantasmagoria. It is sufficient to hint at this application
ot these phenomena, to those who know anything of the subject. r
2 The word suggest is much used by Berkeley, in this appropriate and technical sense, not only in his Theory of Visioti,
but m his Principles of Human Knowledge, and in his Minute Philosopher. It expresses, indeed, the cardinal principle on
which his Theory o/1 Vision hinges; and is now so incorporated with some of our best metaphysical speculations, that one
cannot easily conceive how the use of it was so long dispensed with. Locke (in the passage quoted in the Note, p. 107.)
uses the word excite for the same purpose; but it seems to imply an hypothesis concerning the mechanism of the mind, and
by no means expresses the fact in question with the same force and precision.
It is remarkable, that Dr lleid should have thought it incumbent on him to apologise for introducing into philosophy a
word so familiar to every person conversant with Berkeley’s works. “ I beg leave to make use of the word suggestion be¬
cause I know not one more proper to express a power of the mind, which seems entirely to have escaped the notice of'phi¬
losophers, and to which we owe many of our simple notions which are neither impressions nor ideas, as well as many origi¬
nal principles of belief. I shall endeavour to explain, by an example, what I understand by this word. We all know that
a certain kind of sound suggests immediately to the mind a coach passing in the street; and not only produces the imagina¬
tion, but the belief, that a coach is passing. Yet there is no comparing of ideas, no perception of agreements or disagree¬
ments to produce this belief; nor is there the least similitude between the sound we hear, and the coach we imagine and
believe to be passing.” 8
So far Dr Reid’s use of the word coincides exactly with that of Berkeley ; but the former will be found to annex to it a
meaning more extensive than the latter, by employing it to comprehend not only those intimations which are the result of
experience and habit; but another class of intimations (quite overlooked by Berkeley), those which result from the original
trame or the human mind.—(See Reid’s Inquiry, chap. ii. sect. 7*)
I request the attention of my readers to this last sentence, as I have little doubt that the fact here stated gave rise to
tne theory which Berkeley afterwards adopted, concerning the non-existence of the material world. It is not, indeed, sur¬
prising that a conclusion, so very curious with respect to the objects of sight, should have been, in the first ardour of dis¬
covery, too hastily extended to those qualities also which are the appropriate obiects of touch.
4 Alhazen, Lib. ii. N N. 10. 12. 39.
4 See the end of Prop. 28.
168
PRELIMINARY DISSERTATIONS.
reasonings of Berkeley concerning tlie means by
which experience enables us to judge of the dis¬
tances of near objects. In proof of this, it is
sufficient to mention the explanation he gives of
the manner in which a comparison ot the percep¬
tions of sight and of touch teaches us giadually
to estimate by the eye the distances of all those
objects which are within reach of our hands, or
of which we are accustomed to measure the dis¬
tance, by walking over the intermediate ground.
In rendering this justice to earlier writers, I
have no wish to detract from the originality of
Berkeley. With the single exception, indeed,
of the passage in Malehranche which I have
just referred to, and which it is more than pro¬
bable was unknown to Berkeley when his theory
first occurred to him,1 I have ascribed to his
predecessors nothing more than what he has
himself explicitly acknowledged to belong to
them. All that I wished to do was, to supply
some links in the historical chain, which he has
omitted.
The influence which this justly celebrated
work has had, not only in perfecting the theory
of optics, but in illustrating the astonishing ef¬
fects of early habit on the mental phenomena in
general, will sufficiently account to my intelli¬
gent readers for the length to which the fore¬
going observations upon it have extended.
Next in point of importance to Berkeley’s New
Theory of Vision, which I regard as by far the
most solid basis of his philosophical fame, may be
ranked his speculations concerning the Objects
of General Terms, and his celebrated argument
against the existence of the Material World.
On both of these questions I have elsewhere ex¬
plained my own ideas so fully, that it would be
quite superfluous for me to resume the consi¬
deration of them here.2 3 In neither instance are
his reasonings so entirely original as has been
commonly supposed. In the former, they co¬
incide in substance, although with immense im¬
provements in the form, with those of the scho¬
lastic nominalists, as revived and modified by
Hobbes and Leibnitz. In the latter instance,
they amount to little more than an ingenious
and elegant development of some principles of
Malebranche, pushed to certain paradoxical but
obvious consequences, of which Malebranche,
though unwilling to avow them, appears to have
been fully aware. These consequences, too,
had been previously pointed out by Mr Norris,
a very learned divine of the church of England,
whose name has unaccountably failed in obtain¬
ing that distinction to which his acuteness as a
logician, and his boldness as a theorist, justly
entitled him!5
The great object of Berkeley, in maintaining
his system of idealism, it may be proper to re¬
mark in passing, was to cut up by the roots the
scheme of materialism. “ Matter (he tells us
himself) being once expelled out qf nature, drags
with it so many sceptical and impious notions.
* * * * Without it your Epicureans, Hobbists,
and the like, have not even the shadow of a
pretence, but become the most cheap and easy
triumph in the world.”
Not satisfied with addressing these abstract
speculations to the learned, Berkeley conceived
them to be of such moment to human happiness,
that he resolved to bring them, if possible, with¬
in the reach of a wider circle of readers, by
throwing them into the more popular and amu¬
sing form of dialogues.4 The skill with which
1 Berkeley’s Theory was published when he was only twenty-five ; an age when it can scarcely be supposed that his me¬
taphysical reading had been very extensive.
2 See Philosophical Essays. „ „ . .
3 Another very acute metaphysician of the same church (Arthur Collier, author of a Demonstration of t ic Non-cxis ence
and Impossibility of an External World) has met with still greater injustice. His name is not to be found in any ot our Bio¬
graphical Dictionaries. In point of date, his publication is some years posterior to that of A orris, and there oie i oes no
possess the same claims to originality ; but it is far superior to it in logical closeness and precision, and is not obscured o
the same degree with the mystical theology which Norris (after the example ol Malebranche) connected wit le sc erne
of Idealism. Indeed, when compared with the writings of Berkeley himself, it yields to them less m force o argumen ,
than in composition and variety of illustration. The title of Collier’s book is “ Clavis Universalis, or a New Inquiry a er
Truth, being a Demonstration, &c. &c. By Arthur Collier, Hector of Langford Magna, near Sarum. (Lond. printed or
Robert Gosling, at the Mitre and Crown, against St Dunstan’s Church, Fleet Street, 1713.)” The motto prefixed by Co -
lier to his work is from Malebranche, and is strongly characteristical both of the English and l rench Inquirer afier Tru i.
“ Vulgi assensus et approbatio circa materiam difficilem est certum argumentum falsitatis istius opmionis cui assenti ur.
—(Maleb. De Inquir. Verit. Lib. iii. p. 194.) See Note S S. rT i a
4 I allude here chiefly to Alciphron, or the Minute Philosopher; for as to the dialogues between Hylas and Philonous, t
aspire to no higher merit than that of the common dialogues between A and B ; being merely a compendious way ot s a -
ing and of obviating the principal objections which the author anticipated to his opinions.
DISSERTATION FIRST.
169
he has executed this very difficult and unpro¬
mising task cannot be too much admired. The
characters of his speakers are strongly marked
and happily contrasted; the illustrations exhibit
a singular combination of logical subtlety and of
poetical invention; and the style, while it every¬
where abounds with the rich, yet sober colour¬
ings of the author’s fancy, is perhaps superior,
in point of purity and of grammatical correct¬
ness, to any English composition of an earlier
date.1
The impression produced in England by
Berkeley’s Idealism was not so great as might
have been expected; but the novelty of his pa¬
radoxes attracted very powerfully the attention
of a set of young men who were then prose¬
cuting their studies at Edinburgh, and who
formed themselves into a society for the express
purpose of soliciting from the author an expla¬
nation of some parts of his theory which seemed
to them obscurely or equivocally expressed. To
this correspondence the amiable and excellent
prelate appears to have given every encourage¬
ment ; and I have been told by the best autho¬
rity, that he was accustomed to say, that his
reasonings had been nowhere better understood
than by this club of young Scotsmen.2 The in¬
genious Dr Wallace, author of the Discourse on
the Numbers of Mankind, was one of the leading
members; and with him were associated several
other individuals whose names are now well
known and honourably distinguished in the
learned world. Mr Hume’s Treatise of Human
Nature, which was published in 1739, affords
sufficient evidence of the deep impression which
Berkeley’s writings had left upon his mind; and
to this juvenile essay of Mr Hume’s may be
traced the origin of the most important meta¬
physical works which Scotland has since pro¬
duced.
It is not, however, my intention to prosecute
farther, at present, the history of Scottish phi¬
losophy. The subject may be more convenient¬
ly, and I hope advantageously resumed, after a
slight review of the speculations of some Eng¬
lish and French writers, who, while they pro¬
fessed a general acquiescence in the doctrines of
Locke, have attempted to modify his funda¬
mental principles in a manner totally incon¬
sistent with the views of their master. The re¬
marks which I mean to offer on the modern
French school will afford me, at the same time,
a convenient opportunity of introducing some
strictures on the metaphysical systems which
have of late prevailed in other parts of the Con¬
tinent.
SECTION V.
Hartleian School.
The English writers to whom I have alluded
in the last paragraph, I shall distinguish by the
title of Dr Hartley’s School; for although I by
no means consider this person as the first author
of any of the theories commonly ascribed to him
(the seeds of all of them having been previously
sown in the university where he was educated),
it was nevertheless reserved for him to combine
them together, and to exhibit them to the world
in the imposing form of a system.
Among the immediate predecessors of Hart¬
ley, Dr Law, afterwards Bishop of Carlisle,
1 Dr Warton, after bestowing high praise on the Minute Philosopher, excepts from his encomium “ those passages in the
iourth dialogue, where the author has introduced his fanciful and whimsical opinions about vision.” (Essay on the Writings
and Genius of Pope, Vol. II. p. 264.)—If I were called on to point out the most ingenious and original part of the whole
work, it would be the argument contained in the passages here so contemptuously alluded to by this learned and (on all
questions of taste) most respectable critic.
2 The authority I here allude to is that of my old friend and preceptor, Dr John Stevenson, who was himself a member
of the Rankenian Club, and who was accustomed for many years to mention this fact in his Academical Prelections.
DISS. I. PART II. * \
170
PRELIMINARY DISSERTATIONS.
seems to have been chiefly instrumental in pre¬
paring the way for a schism among Locke s dis¬
ciples. The name of Law was first known to
the public by an excellent translation, accom¬
panied by many learned, and some very judi¬
cious notes, of Archbishop King s work on the
Origin of Evil", a work of which the great ob¬
ject was to combat the Optimism of Leibnitz,
and the Manicheism imputed to Bayle. In
making this work more generally known, the
translator certainly rendered a most acceptable
and important service to the world, and, indeed,
it is upon this ground that his best claim to li¬
terary distinction is still founded.1 In his own
original speculations, he is weak, paradoxical,
and oracular;2 affecting, on all occasions, the
most profound veneration for the opinions of
Locke, but much more apt to attach himself to
the errors and oversights of that great man,
than to enter into the general spirit of his meta¬
physical philosophy.
To this translation, Dr Law prefixed a Dis¬
sertation concerning the Fundamental Principle
of Virtue, by the Reverend Mr Gay: a per¬
formance of considerable ingenuity, but which
would now be entitled to little notice, were it
not for the influence it appears to have had in
suggesting to Dr Hartley the possibility of ac¬
counting for all our intellectual pleasures and
pains, by the single principle of the Association
of Ideas. We are informed by Dr Hartley
himself, that it was in consequence of hearing
some account of the contents of this dissertation,
be was first led to engage in those inquiries
which produced his celebrated Theory of Human
Nature.
The other principle on which this theory pro¬
ceeds (that of the vibrations and vibratiuncles
in the medullary substance of the brain) is also
of Cambridge origin. It occurs in the form of
a query in Sir Isaac Newton’s Optics; and a
distinct allusion to it, as a principle likely to
throw new light on the phenomena of mind, is
to be found in the concluding sentence of Smith’s
Harmonies.
Very nearly about the time when Hartley’s
Theory appeared, Charles Bonnet of Geneva
published some speculations of his own, pro¬
ceeding almost exactly on the same assumptions.
Both writers speak of vibrations (ebranlemens)
in the nerves; and both of them have recourse
to a subtle and elastic ether, co-operating with
the nerves in carrying on the communication
between soul and body.3 This fluid Bonnet
conceived to be contained in the nerves, in a
manner analogous to that in which the electric
fluid is contained in the solid bodies which con¬
duct it; differing in this respect from the Car¬
tesians as well as from the ancient physiologists,
who considered the nerves as hollow tubes or
pipes, within which the animal spirits were in¬
cluded. It is to this elastic ether that Bonnet
ascribes the vibrations of which he supposes the
nerves to be susceptible; for the nerves them¬
selves (he justly observes) have no resemblance
to the stretched cords of a musical instrument.4 * * * 8
1 King’s argument in proof of the prevalence in this world, both of Natural and Moral Good, over the corresponding
Evils, has been much and deservedly admired ; nor are Law’s Notes upon this head entitled to less praise. Indeed, it is
in this part of the work that both the author and his commentator appear, in my opinion, to the greatest advantage.
2 As instances of this I need only refer to the first and third, of his Notes on King; the former of which relates to the
word substance; and the latter to the dispute between Clarke and Leibnitz concerning space. His reasonings on both sub¬
jects are obscured by an affected use of hard and unmeaning words, ill becoming so devoted an admirer of Locke. The
same remark may be extended to an Inquiry into the Ideas of Space and Time, published by Dr Law in 1734.
The result of Law’s speculations on Space and Time is thus stated by himself: “ That our ideas of them do not imply
any external ideatum or objective reality; that these ideas (as well as those of infinity and number) are universal or abstract
ideas, existing under that formality no where but in the mind ; nor affording a proof of any thing, but of the power which
the mind has to form them.”—(Law’s Trans, of King, p. 7- 4th edit.) This language, as we shall afterwards see, approaches
very nearly to that lately introduced by Kant. Dr Law’s favourite author might have cautioned him against such jargon.
(See Essay on the Human Understanding, Book II. Chap, xiii- § 17, 18.)
The absurd application of the schoiastie word substance to empty space; an absurdity in which the powerful mind of
Gravesande acquiesced many years after the publication of the Essay on Human Understanding, has probably contributed
not a little to force some authors into the opposite extreme of maintaining, with Leibnitz and Dr Law, that, our idea of
space does not imply any external ideatum or objective reality. Gravesande’s words are these : “ Substantiae, sunt aut
cogitantes, aut non cogitantes; cogitantes duas novimus, Deum et Mentem nostram : praeter has et alias dari in dubium
non revocamus. Duae etiam substantiae, quae non cogitant, nobis notae sunt Spatium et Corpus.”—Gravesande, Introd.
ad Philosophiam, § 19.
8 Essai Andlytique de I'Ame, Chap. v. See also the additional notes on the first chapter of the seventh part of the Con.
temptation de la Nature. _ • • •, j
* Mais les nerfs sont mous, ils ne sont point tendus comme les cordes d’un instrument; les objets y exciteroient-ils done
DISSERTATION FIRST.
171
Hartley’s Theory differs in one respect from
this, as he speaks of vibrations and vibratiuncles
in the medullary substance of the brain and
nerves. He agrees, however, with Bonnet, in
thinking, that to these vibrations in the nerves
the co-operation of the ether is essentially ne¬
cessary; and, therefore, at bottom the two hy¬
potheses may be regarded as in substance the
same. As to the trifling shade of difference be¬
tween them, the advantage seems to me to be
in favour of Bonnet.
Nor was it only in their Physiological Theo¬
ries concerning the nature of the union between
soul and body, that these two philosophers
agreed. On all the great articles of metaphy¬
sical theology, the coincidence between their
conclusions is truly astonishing. Both held the
doctrine of Necessity in its fullest extent; and
both combined with it a vein of mystical devo¬
tion, setting at defiance the creeds of all esta¬
blished churches. The intentions of both are
allowed, by those who best knew them, to have
been eminently pure and worthy; but it cannot
be said of either, that his metaphysical writings
have contributed much to the instruction or to
the improvement of the public. On the con¬
trary, they have been instrumental in spreading
a set of speculative tenets very nearly allied to
that sentimental and fanatical modification of
Spinozism, which, for many years past, has pre¬
vailed so much, and produced such mischievous
effects in some parts of Germany.1
But it is chiefly by his application of the asso¬
ciating principle to account for all the mental
phenomena, that Hartley is known to the world;
and upon this I have nothing to add to what I
have already stated in another work.—(Phil.
Essays, Essay IV.)—His Theory seems to be al¬
ready fast passing into oblivion; the temporary
popularity which it enjoyed in this country
having, in a great measure, ceased with the
life of its zealous and indefatigable apostle Hr
Priestley. *
It would be unfair, however, to the translator
of Archbishop King, to identify his opinions
with those of Hartley and Priestley. The zeal
with which he contends for man’s free agency
is sufficient, of itself, to draw a strong line of
distinction between his Ethical System and
theirs.—(See his Notes on King, passim.)—But
I must be allowed to say of him, that the gene¬
ral scope of his writings tends, in common with
that of the two other metaphysicians, to depre¬
ciate the evidences of Natural Religion, and
more especially to depreciate the evidences which
the light of nature affords of a life to come ;—
les vibrations analogues a celle d’une corde pincee ? Ces vibrations se communiqueroient-elles a Tinstant au siege de Tame ?
La chose paroit difficile k conqevoir. Mais si Ton admet dans les nerfs un fluide dont la subtilitd et 1’dlasticite approche de
celle de la lumiere ou de Tether, on expliquera facilement par le secours de ce fluide, et lacdleritd avec laquelle les impres¬
sions se communiquent a Tame, et celle avec laquelle Tame Execute tant d’operations differentes.”—(Essai Anal. Chap, v.)
“ Au reste, les physiologistes qui avoient cru que les filets nerveux etoient solides, avoient cede a des apparences trom-
peuses. Ils vouloient d’ailleurs faire osciller les nerfs pour rendre raison des sensations, et les nerfs ne peuvent osciller.
Ils sont mous, et nullement dlastiques. Un nerf coupe ne se retire point. C’est le fluide invisible que les nerfs renfer-
ment, qui est doud de cette dlasticite qu’on leur attribuoit, et d’une plus grande elasticitdencore.”—( Contcmp. de la Nature.
VII. Partie, Chap. i. Note at the end of the chapter.)
M. Quesnai, the celebrated author of the Economical System, has expressed himselt to the same purpose concerning the
supposed vibrations of the nerves: “ Plusieurs physiciens ont pense que le seul ebranlement des nerfs, causd par les objets
qui touchent les organes des corps, suffit pour occasioner le mouvement et le sentiment dans les parties oh les nerfs sont
dbranles. Ils se representent les nerfs comme des cordes fort tendus, qu’un leger contact met en vibration dans toute leur
dtendue. Des philosophes, peu instruits en anatomie, ont pu se former un telle idee ...... Mais cette tension qu on sup¬
pose dans les nerfs, et qui les rend si susceptibles d’dbranlement et de vibration, est si grossierement imaginee qu il seroit
ridicule de s’occuper serieusement a la refuter.” (Econ. Animate, sect. 3. c. 13.) _ _ _ .....
As this passage from Quesnai is quoted by Condillac, and sanctioned by his authority (Traite des Animaux, Chap, m.), it
would appear that the hypothesis which supposes the nerves to perform their functions by means of vibrations was going
fast into discredit, both among the metaphysicians and the physiologists of F ranee, at the very time when it was beginning
to attract notice in England, in consequence of the visionary speculations of Hartley.
1 In a letter which I received from Dr Parr, he mentions a treatise of Dr Hartley’s which appeared about a year before
the publication of his great work ; to which it was meant by the author to serve as a precursor. Of this rare treatise I liad
never before heard. “You will be astonished to hear,” says Dr Parr, “that in this book,, instead of the doctrine of ne¬
cessity, Hartley openly declares for the indifference of the will, as maintained by Archbishop King. ’ We are told by
Hartley himself that his notions upon necessity grew upon him while he was writing his observations upon man; but it
is curious (as Dr Parr remarks), that in the course of a year, his opinions on so very essential a point should have undei-
gone a complete change. '
a Dr Priestley’s opinion of the merits of Hartley’s work is thus stated by himselfSomething was done in this held ot
knowledge by Descartes, very much by Mr Locke, but most of all by Dr Hartley, who has thrown more useiuJ ig i upon
the theory of the mind, than Newton did upon the theorv of the natural world.”—(Remarks on Reid, Beattie, and Uswa ,
p. 2. London, 1774.)
172
PRELIMINARY DISSERTATIONS.
“ a doctrine equally necessary to comfort the
weakness, and to support our lofty ideas of the
grandeur of human nature;”1 and of which it
seems hard to confine exclusively the knowledge
to that portion of mankind who have been fa¬
voured with the light of Revelation. The in¬
fluence of the same fundamental error, arising,
too, from the same mistaken idea, of thus
strengthening the cause of Christianity, may be
traced in various passages of the posthumous
work of the late Bishop of LlandafF. It is won¬
derful that the reasonings of Clarke and of But¬
ler did not teach these eminent men a sounder
and more consistent logic; or, at least, open
their eyes to the inevitable consequences of the
rash concessions which they made to their ad¬
versaries. *
Among the disciples of Law, one illustrious
exception to these remarks occurs in Dr Paley,
whose treatise on Natural Theology is unques¬
tionably the most instructive as well as inte¬
resting publication on that subject which has
appeared in our times. As the hook was in¬
tended for popular use, the author has wisely
avoided, as much as possible, all metaphysical
discussions; hut I do not know that there exists
any other work where the argument from final
causes is placed in so great a variety of pleasing
and striking points of view.
SECTION YI.
Condillac, and other French Metaphysicians of a later date.
While Hartley and Bonnet were indulging
their imagination in theorising concerning the
nature of the union between soul and body,
Condillac was attempting to draw the attention
of his countrymen to the method of studying
the phenomena of Mind recommended and ex¬
emplified by Locke.3 Of the vanity of expect¬
ing to illustrate, by physiological conjectures.
J Smith’s Theory of Moral Sentiments, 6th ed. Yol. I. pp. 325, 326.
Dr Law’s doctrine of the sleep of the soul, to which his high station in the church could not fail to add much weight in
the judgment of many, is, I believe, now universally adopted by the followers of Hartley and Priestley ; the theory of vi¬
brations being evidently inconsistent with the supposition of the soul’s being able to exercise her powers in a separate state
from the body.
2 Without entering at all into the argument with Dr Law or his followers, it is sufficient here to mention, as an histori¬
cal fact, their wide departure from the older lights of the English church, from Hooker downwards. “ All religion,” says
Archbishop Tillotson, whom I select as an unexceptionable organ of their common sentiments, “ is founded on right no¬
tions of God and his perfections, insomuch that Divine Revelation itself does suppose these for its foundations; and can
signify nothing to us unless they be first known and believed; so that the principles of natural religion are the foundation
of that which is revealed.”—(Sermon 41.) “ There is an intrinsical good and evil in things, and the reasons and respects of
moral good and evil are fixed and immutable, eternal and indispensable. Nor do they speak safely who make the Divine
will the rule of moral good and evil, as if there were nothing good or evil in its own nature antecedently to the will of God;
but, that all things are therefore good and evil because God wills them to be so.”—(Sermon 88.) “Natural religion is obe¬
dience to the natural law, and the performance of such duties as natural light, without any express and supernatural reve¬
lation, doth dictate to men. These lie at the bottom of all religion, and are the great fundamental duties which God re¬
quires of all mankind. These are the surest and most sacred of all other laws ; those which God hath rivetted in our souls
and written upon our hearts ; and these are what we call moral duties, and most valued by God, which are of eternal and
perpetual obligation, because they do naturally oblige, without any particular and express revelation from God ; and these
are the foundation of revealed and instituted religion; and all revealed religion does suppose them and build upon them.”—
Sermons 48. 49.
3 It may appear to some unaccountable, that no notice should have been taken, in this Dissertation, of any French me¬
taphysician during the long interval between Malebranche and Condillac. As an apology for this apparent omission, I beg
leave to quote the words of an author intimately acquainted with the history of French literature and philosophy, and emi¬
nently qualified to appreciate the merits of those who have contributed to their progress. “ If we except,” says Mr Adam
Smith, in a Memoir published in 1755, “the Meditations of Descartes, I know of nothing in the works of French writers
which aspires at originality in morals or metaphysics; for the philosophy of Regius and that of Malebranche are nothing
more than the meditations of Descartes unfolded with more art and refinement. But Hobbes, Locke, Dr Mandeville,
Lord Shaftesbury, Dr Butler, Dr Clarke, and Mr Hutcheson, each in his own system, all different and all incompatible,
have tried to be original, at least in some points. They have attempted to add something to the fund of observations cel.
DISSERTATION FIRST.
173
the manner in which the intercourse between
the thinking principle and the external world is
carried on, no philosopher seems ever to have
been more completely aware; and, accordingly,
he confines himself strictly, in all his researches
concerning this intercourse, to an examination
of the general laws by which it is regulated.
There is, at the same time, a remarkable coin¬
cidence between some of his views and those of
the other two writers. All of the three, while
they profess the highest veneration for Locke,
have abandoned his account of the origin of our
ideas for that of Gassendi; and, by doing so,
have, with the best intentions, furnished arms
against those principles which it was their com¬
mon aim to establish in the world.1 It is much
to he regretted, that by far the greater part of
those French writers who have since speculated
about the human mind, have acquired the whole
of their knowledge of Locke’s philosophy through
this mistaken comment upon its fundamental
principle. On this subject I have already ex¬
hausted all that I have to offer on the effect of
Condillac’s writings; and I flatter myself have
sufficiently shown how widely his commentary
differs from the text of his author. It is this
commentary, however, which is now almost
universally received on the Continent as the
doctrine of Locke, and which may justly he re¬
garded as the sheet-anchor of those systems
which are commonly stigmatised in England
with the appellation of French philosophy. Had
Condillac been sufficiently aware of the conse¬
quences which have been deduced (and I must
add logically deduced) from his account of the
origin of our knowledge, I am persuaded, from
his known candour and love of truth, that he
would have been eager to acknowledge and to
retract his error.
In this apparent simplification and generali¬
sation of Locke’s doctrine, there is, it must he
acknowledged, something, at first sight, ex¬
tremely seducing. It relieves the mind from
the painful exercise of abstracted reflection, and
amuses it with analogy and metaphor when it
looked only for the severity of logical discus¬
sion. The clearness and simplicity of Condil¬
lac’s style add to the force of this illusion, and
flatter the reader with an agreeable idea of the
powers of his own understanding, when he finds
himself so easily conducted through the darkest
labyrinths of metaphysical science. It is to this
cause I would chiefly ascribe the great popula¬
rity of his works. They may he read with as
little exertion of thought as a history or a novel;
and it is only when we shut the hook, and at¬
tempt to express in our own words the sub¬
stance of what we have gained, that we have the
mortification to see our supposed acquisitions
vanish into air.
The philosophy of Condillac was, in a more
peculiar manner, suited to the taste of his own
country, where (according to Mad. de Stael)
“ few read a hook but with a view to talk of
it.” s Among such a people, speculations which
are addressed to the power of reflection can
never expect to acquire the same popularity
with theories expressed in a metaphorical lan-
lected by their predecessors, and already the common property of mankind. This branch of science, which the English
themselves neglect at present, appears to have been recently transported into France. I discover some traces of it not only
in the Encycloptdic, but in the Theory of Agreeable Sensations, by M. de Pouilly; and much more in the late discourse of M.
Rousseau, On the Origin and Foundation of the Inequality of Ranks among Men."
Although I perfectly agree with Mr Smith in his general remark on the sterility of invention among the French meta¬
physicians posterior to Descartes, when compared to those of England, I cannot pass over the foregoing quotation with¬
out expressing my surprise, lif, To find the name of Malebranche (one of the highest in modern philosophy) degraded to
a level with that of Regius; and, 2dly, To observe Mr Smith’s silence with respect to Buffier and Condillac, while he men¬
tions the author of the Theory of Agreeable Sensations as a metaphysician of original genius. Of the merits of Condillac,
whose most important works were published several years before this paper of Mr Smith’s, I am about to speak in the text;
and those of Buffier I shall have occasion to mention in a subsequent part of this discourse. In the mean time, I shall only
say of him, that I regard him as one of the most original as well as sound philosophers of whom the eighteenth century has
to boast.
1 Condillac’s earliest work appeared three years before the publication of Hartley’s Theory. It is entitled, “ Essai sur
l Origine des Connoissances Humaines. Ouvrage ou Von reduit a un seul principe tout ce qui concerne Ventendement humain." This
seul principe is the association of ideas. The account which both authors give of the transformation of sensations into ideas
is substantially the same.
* “ En France, on ne lit guere un ouvrage que pour en parler.”—(Allcmagne, Tom. I. p. 292.) The same remark, I am
much afraid, is becoming daily more and more applicable to our own island.
174
PRELIMINARY DISSERTATIONS.
guage, and constantly recalling to the fancy the
impressions of the external senses. The state
of society in France, accordingly, is singularly
unfavourable to the inductive philosophy of the
human mind; and of this truth no proof more
decisive can he produced, than the admiration
with which the metaphysical writings of Con¬
dillac have been so long regarded.
On the other hand, it cannot be denied that
Condillac has, in many instances, been eminent¬
ly successful, both in observing and describing
the mental phenomena; but, in such cases, he
commonly follows Locke as his guide; and,
wherever he trusts to his own judgment, he
seldom fails to wander from his way. The best
part of his works relates to the action and re¬
action of thought and language on each other, a
subject which had been previously very pro¬
foundly treated by Locke, but which Condillac
has had the merit of placing in many new and
happy points of view. In various cases, his
conclusions are pushed too far, and in others
are expressed without due precision; but, on
the whole, they form a most valuable accession
to this important branch of logic; and (what
not a little enhances their value) they have been
instrumental in recommending the subject to
the attention of other inquirers, still better qua¬
lified than their author to do it justice.
In the speculation, too, concerning the origin
and the theoretical history of language, Condil¬
lac was one of the first who made any consider¬
able advances; nor does it reflect any discredit
on his ingenuity, that he has left some of the
principal difficulties connected with the inquiry
very imperfectly explained. The same subject
was soon after taken up by Mr Smith, who, I
think, it must be owned, has rather slurred over
these difficulties, than attempted to remove
them; an omission on his part the more re¬
markable, as a very specious and puzzling ob¬
jection had been recently stated by Rousseau,
not only to the theory of Condillac, but to all
speculations which have for their object the so¬
lution of the same problem. “ If language”
(says Rousseau) “ be the result of human con¬
vention, and if words be essential to the exer¬
cise of thought, language would appear to be
necessary for the invention of language.”1 —
“ But” (continues the same author) “ when, by
means which I cannot conceive, our new gram¬
marians began to extend their ideas, and to
generalise their words, their ignorance must
have confined them within very narrow bounds.
 How, for example, could they ima¬
gine or comprehend such words as matter, mind,
substance, mode, figure, motion, since our phi¬
losophers, who have so long made use of them,
scarcely understand them, and since the ideas
attached to them, being purely metaphysical,
can have no model in nature ?”
“ I stop at these first steps” (continues Rous¬
seau), “ and intreat my judges to pause, and
consider the distance between the easiest part of
language, the invention of physical substantives,
and the power of expressing all the thoughts of
man, so as to speak in public, and influence so¬
ciety. I entreat them to reflect upon the time
and knowledge it must have required to dis¬
cover numbers, abstract words, aorists, and all
the tenses of verbs, particles, syntax, the art of
connecting propositions and arguments, and
how to form the whole logic of discourse. As
for myself, alarmed at these multiplying diffi¬
culties, and convinced of the almost demon¬
strable impossibility of language having been
formed and established by means merely human,
I leave to others the discussion of the problem,
i Whether a society already formed was more
necessary for the institution of language, or a
language already invented for the establishment
of society ?’ ”*
Of the various difficulties here enumerated,
that mentioned by Rousseau, in the last sentence,
was plainly considered by him as the greatest
of all; or rather as comprehending under it all
1 That men never could have invented an artificial language, if they had not possessed a natural language, is an observa¬
tion of Dr Iteid’s; and it is this indisputable and self-evident truth which gives to Rousseau’s remark that imposing plau¬
sibility, which, at first sight, dazzles and perplexes the judgment. I by no means say, that the former proposition affords
a key to all the difficulties suggested by the latter ; but it advances us at least one important step towards their solution.
* Discours sur VOrigine et les Fondemens de I'Inegalite parmi les Hommes
DISSERTATION FIRST.
175
the rest. But this difficulty arises merely from
his own peculiar and paradoxical theory about
the artificial origin of society; a theory which
needs no refutation, but the short and luminous
aphorism of Montesquieu, that “ man is born in
society, and there he remains.” The other dif¬
ficulties touched upon by Rousseau, in the for¬
mer part of this quotation, are much more se¬
rious, and have never yet been removed in a
manner completely satisfactory: And hence
some very ingenious writers have been led to
conclude, that language could not possibly have
been the work of human invention. This ar¬
gument has been lately urged with much acute¬
ness and plausibility by Dr Magee of Dublin,
and by M. de Bonald of Paris.1 It may, how¬
ever, be reasonably questioned, if these philoso¬
phers would not have reasoned more logically,
had they contented themselves with merely af¬
firming, that the problem has not yet been solv¬
ed, without going so far as to pronounce it to
n be absolutely insolvable. For my own part,
when I consider its extreme difficulty, and the
short space of time during which it has engaged
the attention of the learned, I am more dispos¬
ed to wonder at the steps which have been al¬
ready gained in the research, than at the num¬
ber of desiderata which remain to employ the
ingenuity of our successors. It is justly re¬
marked by Dr Ferguson, that, “ when language
has attained to that perfection to which it ar¬
rives in the progress of society, the speculative
mind, in comparing the first and the last stages
of the progress, feels the same sort of amaze¬
ment with a traveller, who, after rising insen¬
sibly on the slope of a hill, comes to look down
from a precipice, to the summit of which he
scarcely believes he could have ascended with¬
out supernatural aid.”2
With respect to some of the difficulties point¬
ed out by Rousseau and his commentators, it
may be here remarked in passing (and the ob¬
servation is equally applicable to various pas¬
sages in Mr Smith’s dissertation on the same
subject), that the difficulty of explaining the
theory of any of our intellectual operations af¬
fords no proof of any difficulty in applying that
operation to its proper practical purpose; nor
is the difficulty of explaining the metaphysical
nature of any part of speech a proof, that, in its
first origin, it implied any extraordinary effort
of intellectual capacity. How many metaphy¬
sical difficulties might be raised about the ma¬
thematical notion of a line ? And yet this notion
is perfectly comprehended by every peasant,
when he speaks of the distance between two
places; or of the length, breadth, or height of
his cottage. In like manner, although it may
be difficult to give a satisfactory account of the
origin and import of such words as of or by, we
ought not to conclude, that the invention of
them implied any metaphysical knowledge in
1 The same theory has been extended to the art of writing; but if this art was first taught to man by an express reve¬
lation from Heaven, what account can be given of its present state in the great empire of China ? Is the mode of writing
practised there of divine or of human origin ?
s Principles of Moral and Political Science, Vol- I. p. 43. Edin. 1792. To this observation may be added, by way of com¬
ment, the following reflections of one of the most learned prelates of the English church :—“ Man, we are told, had a lan¬
guage from the beginning; for he conversed with God, and gave to every animal its particular name. But how came man
by language ? He must either have had it from inspiration, ready formed from his Creator, or have derived it by the exer¬
tion of those faculties of the mind, which were implanted in him as a rational creature, from natural and external objects
with which he was surrounded. Scripture is silent on the means by which it was acquired. We are not, therefore, war¬
ranted to affirm, that it was received by inspiration, and there is no internal evidence in language to lead us to such a sup¬
position. On this side, then, of the question, we have nothing but uncertainty; but on a subject, the causes of which are
so remote, nothing is more convenient than to refer them to inspiration, and to recur to that easy and comprehensive argu¬
ment,
Ails irsXusro (houXn'
that is, man enjoyed the great privilege of speech, which distinguished him at first, and still continues to distinguish him
as a rational creature, so eminently from the brute creation, without exerting those reasoning faculties, by which he was in
other respects enabled to raise himself so much above their level. Inspiration, then, seems to have been an argument
adopted and made necessary by the difficulty of accounting for it otherwise; and the name of inspiration carries with it an
awfulness, which forbids the unhallowed approach of inquisitive discussion.”—(Essay on the Study of Antiquities, by Dr Bur¬
gess, 2d edit. Oxford, 1732. Pp. 85, 86.)
It is farther remarked very sagaciously, and I think very decisively, by the same author, that “ the supposition of man
having received a language ready formed from his Creator, is actually inconsistent with the evidence of the origin of our
ideas, which exists in language For, as the origin of our ideas is to be traced in the words through which the ideas are
conveyed, so the origin oflanguage is referable to the source from whence our (first) ideas are derived, namely, nature1 and
external objects.”—(Ibid. pp. 83, 84.)
176
PRELIMINARY DISSERTATIONS.
the individual who first employed them.1 Their
import, we see, is fully understood by children
of three or four years of age.
In this view of the History of Language I
have been anticipated by Dr Ferguson. “ Parts
of speech” (says this profound and original
writer), which, in speculation, cost the gram¬
marian so much study, are, in practice, familiar
to the vulgar. The rudest tribes, even the idiot
and the insane, are possessed of them. They
are soonest learned in childhood, insomuch that
we must suppose human nature, in its lowest
state, competent to the use of them; and, with¬
out the intervention of uncommon genius, man¬
kind, in a succession of ages, qualified to ac¬
complish in detail this amazing fabric of lan¬
guage, which, when raised to its height, appears
so much above what could be ascribed to any
simultaneous effort of the most sublime and
comprehensive abilities.”2
It is, however, less in tracing the first rudi¬
ments of speech, than in some collateral inqui¬
ries concerning the genius of different languages,
that Condillac’s ingenuity appears to advantage.
Some of his observations, in particular, on the
connection of natural signs with the growth of
a systematical prosody, and on the imitative arts
of the Greeks and Romans, as distinguished
from those of the moderns, are new and cu¬
rious ; and are enlivened with a mixture of his¬
torical illustration, and of critical discussion,
seldom to he met with among metaphysical
writers.
But through all his researches, the radical
error may, more or less, be traced, which lies
at the bottom of his system ;3 and hence it is,
1 In this remark I had an eye to the following passage in Mr Smith’s dissertation“ It is worth while to observe, that
those prepositions, which, in modern languages, hold the place of the ancient cases, are, of all others, the most general, and
abstract, and metaphysical; and, of consequence, would prolably be the last invented. Ask any man of common acuteness, what
relation is expressed by the preposition above? He will readily answer, that of superiority. 15y the preposition below ? He *
will as quickly reply, that of inferiority. But ask him what relation is expressed by the preposition off and, if he has not
beforehand employed his thoughts a good deal upon these subjects, you may safely allow him a week to consider of his
answ'er.”
5 The following judicious reflections, with which M Baynouard concludes the introduction to his Elemens de la Langur.
Romane, may serve to illustrate some of the above observations. The modification of an existing language is, I acknow¬
ledge, a thing much less wonderful than the formation of a language entirely new ; but the processes of thought, it is rea¬
sonable to think, are, in both cases, of the same kind; and the consideration of the one is at least a step gained towards the
elucidation of the other.
“ La langue Ilomane est peut-etre la seule a la formation de laquelle il soit permis de remonter ainsi, pour dexouvrir et
expliquer le secret de son industrieux mecanisme. . . . J’ose dire que 1’esprit philosophique, consult^ sur le choix des
moyens qui devraient dpargner a 1’ignorance beaucoup d’dtudes penibles et fastidieux, n’eut pas dtd aussi heureux quel’ig-
norance elle-meme ; il est vrai qu’elle avoit deux grands maitres ; la Necessite et le Tems.
“ En considerant a quelle epoque d’ignorance et de barbarie s’est forme et perfectionne ce nouvel idiome, d’apres des
principes indiquds seulement par 1’analogie et 1’euphonie, on se dira peut-etre comme je me le suis dit; 1’homme porte en
soi-meme les principes d’une logique naturelle, d’un instinct regulateur, que nous admirons quelquefois dans les enfans.
Oui, la Providence nous a dote' de la faculte indestructible et des moyens ingenieux d’exprimer, de communiquer, d’dterni-
ser par la parole, et par les signes permanens ou elle se reproduit, cette pensee qui est Pun de nos plus beaux attributs, et
qui nous distingue si eminemment et si avantageusement dans Pordre de la creation.”—(Elemens de la Grammaire de la Langue
Romane avant VAn. 1000. Pp. 104, 105. A Paris, 1810.)
In the theoretical history of language, it is more than probable, that some steps will remain to exercise the ingenuity of
our latest posterity. Nor will this appear surprising, when we consider how impossible it is for us to judge, from our own
experience, of the intellectual processes which pass in the minds of savages. Some instincts, we know, possessed both by them
and by infants (that ot imitation, for example, and the use of natural signs), disappear in by far the greater number of in¬
dividuals, almost entirely in the maturity of their reason. It does not seem at all improbable, that other instincts connect¬
ed with the invention ot speech, may be confined to that state of the intellectual powers which requires their guidance:
nor is it quite impossible, that some latent capacities of the understanding may be evolved by the pressure of necessity.
The facility with which infants surmount so many grammatical and metaphysical difficulties, seems to me to add much
weight to these conjectures.
In tracing the first steps of the invention of language, it ought never to be forgotten, that ive undertake a task more si¬
milar than might at first be supposed, to that of tracing the first operations of the infant mind. In both cases, we are apt
to attempt an explanation from reason alone, of what requires the co-operation of very different principles. To trace the
theoretical history of geometry, in which we know for certain, that all the transitions have depended on reasoning alone, is
a problem which has not yet been completely solved. Nor has even any satisfactory account been hitherto given of the
experimental steps by which men were gradually led to the use of iron. And yet how simple are these problems, when
compared with that relating to the origin and progress of language!
3 A remarkable instance of this occurs in that part of Condillac’s Cours d'Etude, where he treats of the art of writing :
“ Vous savez, Monseigneur, comment les memes noms ont etd transporte's des objets qui tombent sous ks sens a ceux qui fes
echappent. Vous avez remarque, qu’il y en a qui sont encore en usage dans 1’un et 1’autre acceptation, et qu’il y en a qui
sont devenus les noms propres des choses, dont ils avoient d’abord dtd les signes figures.
“ Les premiers, tel que le mouvement de 1’ame, son penchant, sa reflexion, donnent un corps a des choses qui n’en ont pas.
Les seconds, tels que la pensee, la volonte, le desir, ne peignent plus rien, et laissent aux idees abstraites cette spiritualite
qui les de'robe aux sens. Mais si le langage doit etre I’image de nos pensees, on a perdu beaucoup, lorsqu’ oubliant la pre-
DISSERTATION FIRST.
177
that, with all his skill as a writer, he never ele¬
vates the imagination, or touches the heart.
That he wrote with the best intentions, we have
satisfactory evidence; and yet hardly a philo¬
sopher can be named, whose theories have had
more influence in misleading the opinions of his
contemporaries.1 In France, he very early
attained to a rank and authority not inferior to
those which have been so long and so deserved¬
ly assigned to Locke in England; and even in
this country, his works have been more gene¬
rally read and admired, than those of any fo¬
reign metaphysician of an equally recent date.
The very general sketches to which I am here
obliged to confine myself, do not allow me to
take notice of various contributions to metaphy¬
sical science, which are to he collected from
writers professedly intent upon other subjects.
I must not, however, pass over in silence the
name of Buflbn, who, in the midst of those
magnificent views of external nature, which
the peculiar character of his eloquence fitted
him so admirably to delineate, has frequently
indulged himself in ingenious discussions con¬
cerning the faculties both of men and of brutes.
His subject, indeed, led his attention chiefly to
man, considered as an animal; hut the pecu¬
liarities which the human race exhibit in their
physical condition, and the manifest reference
which these bear to their superior rank in the
creation, unavoidably engaged him in specula¬
tions of a higher aim, and of a deeper interest.
In prosecuting these, he has been accused (and
perhaps with some justice) of ascribing too
much to the effects of bodily organisation on
the intellectual powers; hut he leads his reader
in so pleasing a manner from matter to mind,
that I have no doubt he has attracted the curio¬
sity of many to metaphysical inquiries, who
would never otherwise have thought of them.
In his theories concerning the nature of the
brutes, he has been commonly considered as
leaning to the opinion of Descartes; but I can¬
not help thinking, without any good reason.
Some of his ideas on the complicated operations
of insects appear to me just and satisfactory;
and while they account for the phenomena,
without ascribing to the animal any deep or
comprehensive knowledge, are far from de¬
grading him to an insentient and unconscious
machine.
In his account of the process by which the
use of our external senses (particularly that of
sight) is acquired, Buffon has in general foliow-
iniere signification des mots, on a dff'ace jusqu’au traits qu’ils donnoient aux idees. Toutes les langues sont en cela plusou
moins defectueuses, toutes aussi ont des tableaux plus ou moins conserves.”—(Cours d'Etude, Tome II. p. 212. a Parme,
1775.) ... . , .
Condillac enlarges on this point at considerable length ; endeavouring to show, that whenever we lose sight of the ana¬
logical origin of a figurative word, we become insensible to one of the chief beauties of language. “ In the word examen,
for example, a Frenchman perceives only the proper name of one of our mental operations. A Roman attached to it the
same idea, and received over and above the image of weighing and balancing. The case is the same with the words awe and
anima ; pensee and cogitatio.
In this view of the subject, Condillac plainly proceeded on his favourite principle, that all our notions of our mental ope.
rations are compounded of sensible images. Whereas the fact is, that the only just notions we can form of the powers of
the mind are obtained by abstracting from the qualities and laws of the material world. In proportion, therefore, as the
analogical origin of a figurative word disappears, it becomes a fitter instrument of metaphysical thought and reasoning—
(See Philosophical Essays, Part I. Essay V. Chap, iii.)
1 A late writer (M. de Bonald), whose philosophical opinions, in general, agree nearly with those of La Harpe, has, how¬
ever, appreciated very differently, and, in my judgment, much more sagaciously, the merits, of Condillac : “ Condillac a eu
sur I’esprit philosophique du dernier siecle, Pinfluence que Voltaire a prise sur 1’esprit religieux, et J. J. Rousseau sur les
opinions politiques. Condillac a mis de la sdcheresse et de la minutie dans les esprits; Voltaire du penchant it la raillerie
et k la frivolite ; Rousseau les a rendus chagrins et mecontens Condillac a encore plus fausse I’esprit de la
nation, parce que sa doctrine etoit enseignee dans les premieres etudes a des jeunes gens qui n’avoient encore lu ni Rous¬
seau ni Voltaire, et que la maniere de raisonner et la direction philosophique de I’esprit s’etdndent a tout.”—(Recherchcs
Phil. Tome I. pp. 187, 188.)
The following criticism on the supposed perspicuity of Condillac’s style is so just and philosophical, that I cannot refrain
from giving it a place here : Condillac est, ou paroit etre, clair et methodique ; mais il faut prendre garde, que la clarte
des pensdes, comme la transparence des objets physiques, peut tenir d’un de'faut de profondeur, et que la methode dans les
dcrits, qui suppose la patience de I’esprit, n’en prouve pas toujours la justesse ; et moins encore la fecondite. II y a aussi
une clarte de style en quelque sorte toute materielle, qui n’est pas incompatible avec 1’obscuritd dans les idees. Rien de
plus facile a entendre que les mots de sensations transformies dont Condillac s’est servi, parce que ces mots ne parlent qu a
1’imagination, qui se figure a volontd des transformations et des changemens. Mais cette transformation, appliquee aux
operations de I’esprit, n’est qu’un mot vide de sens; et Condillac lui-meme auroit ete bien embarrasse d’en dormer une
explication satisfaisante. Ce philosophe me paroit plus heureux dans ses apper^us que dans ses demonstrations: La route
de la verite semble quelquefois s’ouvrir devant lui, mais retenu par la circonspection naturelle a un esprit sans chaleur, et
intimidd par la faiblesse de son propre systeme, il n’ose s’v engager.”—(Ibid. Tome I. pp. 33. 34.)
DISS. I. PART II. Z
178
preliminary dissertations.
ed the principles of Berkeley; and, notwith¬
standing some important mistakes which have
escaped him in his applications of these prin¬
ciples, I do not know that there is anywhere to
be found so pleasing or so popular an exposition
of the theory of vision. Nothing certainly was
ever more finely imagined, than the recital
which he puts into the mouth of our first pa¬
rent, of the gradual steps by which he learned
the use of his perceptive organs ; and although
there are various parts of it which will not hear
the test of a rigorous examination, it is impos¬
sible to read it without sharing in that admira¬
tion, with which we are told the author himself
always regarded this favourite effusion of his
eloquence.
Nor are these the only instances in which
Buffon has discovered the powers of a metaphy¬
sician. His thoughts on probabilities (a sub¬
ject widely removed from his favourite studies)
afford a proof how strongly some metaphysical
questions had laid hold of his curiosity, and
what new lights he was qualified to throw on
them, if he had allowed them to occupy more
of his attention.1 * 3 * In his observations, too, on
the peculiar nature of mathematical evidence,
he has struck into a train of the soundest think¬
ing, in which he has been very generally fol¬
lowed by our later logicians.9 Some particular
expressions in the passage I refer to are excep¬
tionable; but his remarks on what he calls
Verites de Definition are just and important;
nor do I remember any modern writer, of an
earlier date, who has touched on the same argu¬
ment. Plato, indeed, and after him Proclus,
had called the definitions of geometry Hypothe¬
ses ; an expression which may be considered as
involving the doctrine which Buffon and his
successors have more fully unfolded.
What the opinions of Buffon were on those
essential questions, which were then in dispute
among the French philosophers, his writings do
not furnish the means of judging with certainty.
In his theory of Organic Molecules, and of In¬
ternal Moulds, he has been accused of entertain¬
ing views not very different from those of the
ancient atomists; nor would it perhaps be easy
to repel the charge, if we were not able to op¬
pose to this wild and unintelligible hypothesis
the noble and elevating strain, which in general
so peculiarly characterises his descriptions of
natqre. The eloquence of some of the finest
passages in his works has manifestly been in¬
spired by the same sentiment which dictated to
one of his favourite authors the following just
and pathetic reflection:—“ Le spectacle de la
nature, si vivant, si anime pour ceux qui recon-
noissent un Dieu, est mort aux yeux de Tath^e,
et dans cette grande harmonic des etres ou tout
parle de Dieu d’une voix si douce, il n’aper^oit
qu’un silence eternel.”5 * * *
I have already mentioned the strong bias to¬
wards materialism which the authors of the En¬
cyclopedic derived from Condillac’s comments
upon Locke. These comments they seem to
have received entirely upon credit, without ever
being at pains to compare them with the origi¬
nal. Had D’Alembert exercised freely his own
judgment, no person was more likely to have
perceived their complete futility; and, in fact,
he has thrown out various observations which
strike at their very root. Notwithstanding,
however, these occasional glimpses of light, he
invariably reverts to the same error, and has
once and again repeated it in terms as strong as
Condillac or Gassendi.
The author who pushed this account of the
origin of our knowledge to the most extraordi¬
nary and offensive consequences, was Helvetius.
His book, De VEsprit, is said to have been com-
1 See his Essai cT Arithmctlque Morale.
3 See the First Discourse prefixed to his Natural History, towards the end.
3 Rousseau—In a work by Hdrault de Sechelles (entitled Voyages a Montbar, contemnt des details trh interessans sur le
caractere, la persunne, et les ecrits de Buffon, Paris, 1801), a very different idea of his religious creed is given from that which
I have ascribed to him ; but, in direct opposition to this statement, we have a letter, dictated by Buffon, on his death-bed,
to Madame Necker, in return for a present of her husband’s book, On the Importance of Religious Opinions. The letter (we
are told) is in the hand-writing of Buffon’s son, who describes his father as then too weak to hold the pen.—(Melanges ex¬
traits des Manuscrits de Madame Necker. 3 Vols. Paris, 1788.)
The sublime address to the Supreme Being, with which Buffon closes his reflections on the calamities of war, seems to
breathe the very soul of Fenelon. “ Grand Dieu ! dont la seule presence soutient la nature et maintient 1’harmonie des
loix de I’univers,” &c. &c. &,c
DISSERTATION FIRST.
179
posed of materials collected from the conversa¬
tions of the society in which he habitually lived;
and it has accordingly heen quoted as an au¬
thentic record of the ideas then in fashion among
the wits of Paris. The unconnected and desul¬
tory composition of the work certainly furnishes
some intrinsic evidence of the truth of this
anecdote.
According to Helvetius, as all our ideas are
derived from the external senses,1 the causes of
the inferiority of the souls of brutes to those of
men, are to he sought for in the difference be¬
tween them with respect to bodily organisation.
In illustration of this remark he reasons as fol¬
lows :—
“1. The feet of all quadrupeds terminate ei¬
ther in horn, as those of the ox and the deer;
or in nails, as those of the dog and the wolf; or
in claws, as those of the lion and the cat. This
peculiar organisation of the feet of these animals
deprives them not only of the sense of touch,
considered as a channel of information with re¬
spect to external objects, hut also of the dexte¬
rity requisite for the practice of the mechanical
arts.
“ 2. The life of animals, in general, being of
a shorter duration than that of man, does not
permit them to make so many observations, or
to acquire so many ideas.
“ 3. Animals being better armed and better
clothed by nature than the human species, have
fewer wants, and consequently fewer motives to
stimulate or to exercise their invention. If the
voracious animals are more cunning than others,
it is because hunger, ever inventive, inspires
them with the art of stratagems to surprise their
prey.
“ 4). The lower animals compose a society
that flies from man, who, by the assistance of
weapons made by himself, is become formidable
to the strongest amongst them.
“ 5. Man is the most prolific and versatile
animal upon earth. He is horn and lives in
every climate; while many of the other animals,
as the lion, the elephant, and the rhinoceros, are
found only in a certain latitude. And the more
any species of animals capable of making obser¬
vations is multiplied, the more ideas and the
greater ingenuity is it likely to possess.
“ But some may ask (continues Helvetius),
why monkeys, whose paws are nearly as dexte¬
rous as our hands, do not make a progress equal
to that of man ? A variety of causes (he ob¬
serves) conspire to fix them in that state of in¬
feriority in which we find them:—1. Men are
more multiplied upon the earth. 2. Among the
different species of monkeys, there are few
whose strength can be compared with that of
man; and, accordingly, they form only a fugi¬
tive society before the human race. 3. Monkeys
being frugiverous, have fewer wants, and, there¬
fore, less invention than man. 4. Their life is
shorter. And, finally, the organical structure
of their bodies keeping them, like children, in
perpetual motion, even after their desires are sa¬
tisfied, they are not susceptible of lassitude
{ennuiJ, which ought to be considered (as I
shall prove afterwards) as one of the principles
1 In combating the philosophy of Helvetius, La Harpe (whose philosophical opinions seem, on many occasions, to have
been not a little influenced by his private partialities and dislikes) exclaims loudly against the same principles to which he
had tacitly given his unqualified approbation in speaking of Condillac. On this occasion he is at pains to distinguish between
the doctrines of the two writers; asserting that Condillac considered our senses as only the occasional causes of our ideas,
while Helvetius represented the former as the productive causes of the latter—f Cours de Litterat. Tome XV. pp. 348, 349.)
But that this is by no means reconcileable with the general spirit of Condillac’s works (although perhaps some detached expres¬
sions may be selected from them admitting of such an interpretation), appears sufficiently from the passages formerly quot¬
ed. In addition to these, I beg leave to transcribe the following : “ Dans le systeme que toutes nos connoisances viennent
des sens, rien n’est plus aise que de se faire une notion exacte des iddes. Car elles ne sont que des sensations ou des por¬
tions extraites de quelque sensation pour etre considerees a part; ce qui produit deux sortes d’idees, les sensible^ et les
abstraites.”—(Traitc des Systemes, Chap, vi.) “ Puisque nous avons vu que le souvenir n’est qu’une maniere de sentir, c’est
une consequence, que les idees intellectuelles ne different pas essentiellement des sensations memes.”—(Traite des Sensa¬
tions, Chap. viii. § 33.) Is not this precisely the doctrine and even the language of Helvetius ?
In the same passage of the Lycie, from which the above quotation is taken from La Harpe, there is a sweeping judgment
pronounced on the merits of Locke, which may serve as a specimen of the author’s competency to decide on metaphysical
questions : “ Locke a prouvd autant qu’il est possible a 1’homme, que I’ame est une substance simple et indivisible, et par
consequent immaterielle. Cependant, il ajoute, qu’il n’oseroit affirmer que Dieu ne puisse douer la matiere de pensee.
Condillac est de son avis sur le premier article, et le combat sur le second. Je suis entierement de 1’avis de Condillac, et
tons les bons mttaphysiciens conviennent que c'est la seule inexactitude qu'on puisse relever dans I'ouvrage de Locke."—(Cours de LitteraU
Tome XV. p. 149.)
180
PRELIMINARY DISSERTATIONS.
to which the human mind owes its improve¬
ment.
“ By combining (he adds) all these differences
between the nature of man and of beast, we may
understand why sensibility and memory, though
faculties common to man and to the lower ani¬
mals, are in the latter only sterile qualities.”1
The foregoing passage is translated literally
from a note on one of the first paragraphs of the
book De VEsprit; and in the sentence of the
text to which the note refers, the author trium¬
phantly asks, £C Who can doubt, that if the wrist
of a man had been terminated by the hoof of a
horse, the species would still have been wander¬
ing in the forest ?”
Without attempting any examination of this
shallow and miserable theory, I shall content
myself with observing, that it is not peculiar to
the philosophers of modern France. From the
Memorabilia of Xenophon it appears, that it was
current among the sophists of Greece; and the
answer given it by Socrates is as philosophical
and satisfactory as any thing that could possibly
be advanced in the present state of the sciences.
“ And canst thou doubt, Aristodemus, if the
gods take care of man ? Hath not the privilege
of an erect form been bestowed on him alone ?
Other animals they have provided with feet, by
which they may he removed from one place to
another; hut to man they have also given the
use of the hand. A tongue hath been bestowed
on every other animal; but what animal, except
man, hath the power of making his thoughts in¬
telligible to others ?
“ Nor is it with respect to the body alone that
the gods have shown themselves bountiful to
man. WTio seeth not that he is as it were a
god in the midst of this visible creation ? So
far doth he surpass all animals whatever in the
endowments of his body and his mind. For if
the body of the ox had been joined to the mind
of man, the invention of the latter would have
been of little avail, while unable to execute his
purposes with facility. Nor would the human
form have been of more use to the brute, so long
as he remained destitute of understanding. But
in thee, Aristodemus, hath been joined to a
wonderful soul, a body no less wonderful; and
sayst thou, after this, the gods take no care of
me ? What wouldst thou then more to con¬
vince thee of their care ?” 2
A very remarkable passage to the same pur¬
pose occurs in Galen’s treatise, De Usu Partium.
“But as of all animals man is the wisest, so
hands are well fitted for the purposes of a wise
animal. For it is not because he had hands
that he is therefore wiser than the rest, as An¬
axagoras alleged; hut because he was wiser than
the rest that he had therefore hands, as Aris¬
totle has most wisely judged. Neither was it
his hands, hut his reason, which instructed man
in the arts. The hands are only the organs by
which the arts are practised.” 3
The contrast, in point of elevation, between
the tone of French philosophy, and that of the
best heathen moralists, was long ago remarked
by Addison; and of this contrast it would be
difficult to find a better illustration than the
passages which have just been quoted.
The disposition of ingenious men to pass sud¬
denly from one extreme to another in matters of
controversy, has, in no instance, been more
strikingly exemplified than in the opposite theo¬
ries concerning the nature of the brutes, which
successively became fashionable in France du¬
ring the last century. While the prevailing
creed of French materialists leads to the rejec¬
tion of every theory which professes to discri¬
minate the rational mind from the animal prin¬
ciple of action, it is well known that, hut a few
years before, the disciples of Descartes allowed
no one faculty to belong to man and brutes in
common; and even went so far as to consider
the latter in the light of mere machines. To
this paradox the author was probably led, partly
by his anxiety to elude the objection which the
1 It is not a little surprising that, in the above enumeration, Helvetius takes no notice of the want of language in the
lower animals ; a faculty without which, the multiplication of individuals could contribute nothing to the improvement of
the species. Nor is this want of language in the brutes owing to any defect in the organs of speech ; as sufficiently appears
from those tribes which are possessed of the power of articulation in no inconsiderable degree. It plainly indicates, there¬
fore, some defect in those higher principles which are connected with the use of artificial signs-
a Mrs Sarah Fielding’s Translation.
* Galen, De Us. Part. 1. 1. e. 3.
DISSERTATION FIRST.
181
faculties of the lower animals have been sup¬
posed to present to the doctrine of the immorta¬
lity of the soul, and partly by the difficulty of
reconciling their sufferings with the Divine
Goodness.
Absurd as this idea may now appear, none of
the tenets of Descartes were once adopted with
more implicit faith by some of the profoundest
thinkers in Europe. The great Pascal admired
it as the finest and most valuable article of the
Cartesian system ; and of the deep impression it
made on the mind of Malebranche, a most de¬
cisive proof was exhibited by himself in the pre¬
sence of Fontenelle. “ M. de Fontenelle con-
toit,” says one of his intimate friends,1 “ qu’un
jour etant alle voir Malehranche aux PP. de
TOratoire de la Rue St Honore, une grosse
chienne de la maison, et qui etoit pleine, entra
dans la salle ou ils se promenoient, vint caresser
le P. Malebranche, et se rouler a ses pieds.
Apres quelques mouvemens inutiles pour la
chasser, le philosophe lui donna un grand coup
de pied, qui fit jetter a la chienne un cri de dou-
leur, et a M. de Fontehelle un cri de compas¬
sion. Eh quoi (lui dit froidement le P. Male¬
branche) ne s^avez vous pas bien que cela ne se
sent point ?”
On this point Fontenelle, though a zealous
Cartesian, had the good sense to dissent openly
from his master, and eA en to express his appro¬
bation of the sarcastic remark of La Motte, que
cette opinion sur lesanimaux etoit une debauche de
raisonnement. Is not the same expression equally
applicable to the opposite theory quoted from
Helvetius ? 2
From those representations of human nature
which tend to assimilate to each other the facul¬
ties of man and of the brutes, the transition to
atheism is not very wide. In the present in¬
stance, both conclusions seem to be the neces¬
sary corollaries of the same fundamental maxim.
For if all the sources of our knowledge are to he
found in the external senses, how is it possible
for the human mind to rise to a conception of
the Supreme Being, or to that of any other truth
either of natural or of revealed religion ?
To this question Gassendi and Condillac, it
cannot be doubted, were both able to return an
answer, which seemed to themselves abundantly
satisfactory. But how few of the multitude are
competent to enter into these refined explana¬
tions ? And how much is it to be dreaded, that
the majority will embrace, with the general prin¬
ciple, all the more obvious consequences which
to their own gross conceptions it seems neces¬
sarily to involve ? Something of the same sort
may be remarked in the controversy about the
freedom of the human will. Among the multi¬
tudes whom Leibnitz and Edwards have made
converts to the scheme of necessity, how com¬
paratively inconsiderable is the number who
have acquiesced in their subtle and ingenious
attempts to reconcile this scheme with man’s ac¬
countableness and moral agency ?
Of the prevalence of atheism at Paris, among
the higher classes, at the period of which we are
now speaking, the Memoires and Correspondance
of the Baron de Grimm afford the most unques¬
tionable proofs.3 His friend Diderot seems to
have been one of its most zealous abettors; who,
1 The Abb^ Trublet in the Mercure de Juillet, 1757 (See CEuvres de Fontenelle, Tome II. p. 137. Amsterdam, 17b‘4.)
2 In La Fontaine’s Discours d Madame de la Sabliere (Liv. X. Fable I.), the good sense with which he points out the ex¬
travagance of both these extremes is truly admirable. His argument (in spite of the fetters of rhyme) is stated, not only
with his usual grace, but with singular clearness and precision ; and considering the period when he wrote, reflects much
honour on his philosophical sagacity.
8 The Systeme de la Nature (the boldest, if not the ablest, publication of the Parisian atheists) appeared in 1770. It bore
on the title-page the name of Mirabaud, a respectable but not very eminent writer, who, after long filling the office of per¬
petual secretary to the French Academy, died at a very advanced age in 1760. (He was chiefly known as the author of
very indifferent translations of Tasso and Ariosto.) It is now, however, universally admitted that Mirabaud had no share
whatever in the composition of the Systeme de la Nature. It has been ascribed to various authors; nor am I quite certain,
that, among those who are most competent to form a judgment upon this point, there is yet a perfect unanimity. In
one of the latest works which has reached this country from France (the Correspondance inidite de Galiani, 1818), it seems to
be assumed by the editors, as an acknowledged fact, that it proceeded from the pen of the Baron d’Holbach. The Abbe
Galiani having remarked, in one of his letters to Madame Epinay, that it appeared to him to come from the same hand with
the Christianisme Devoile and the Militaire Philosophe, the editors remark in a note, “ On peut rendre homage a la sagacitd
de I’Abbe Galiani. Le Christianisme Devoile est en effet le premier ouvrage philosophique du Baron d’Holbach. C’est en
vain que la Biographic Universelle nous assure, d’apres le temoignage de Voltaire, que cet ouvrage est de Damilaville.”
Having mentioned the name of Damilaville, I am tempted to add, that the article relating to him in the Biographic Uni-
verselle, notwithstanding the incorrectness with which it is charged in the foregoing passage, is not unworthy of the reader’s
182
PRELIMINARY DISSERTATIONS.
it appears from various accounts, contributed to
render it fashionable, still more by the extraor¬
dinary powers of his conversation, than by the
odd combination of eloquence and of obscurity
displayed in all bis metaphysical productions.1
In order, however, to prevent misapprehen¬
sion of my meaning, it is proper for me to cau¬
tion my readers against supposing that all the
eminent French philosophers of this period were
of the same school with Grimm and Diderot.
On this subject many of our English writers
have been misled by taking for granted that to
speak lightly of final causes is, of itself, sufficient
proof of atheism. That this is a very rash as
well as uncharitable conclusion, no other proof
is necessary than the manner in which final
causes are spoken of by Descartes himself, the
great object of whose metaphysical writings
plainly was, to establish by demonstration the
existence of God. The following vindication of
this part of the Cartesian philosophy has been
lately offered by a French divine, and it may be
extended with equal justice to Buffon and many
others of Descartes’s successors : “ Quelques au¬
teurs, et particulierement Leibnitz, ont critique
cette partie de la doctrine de Descartes; mais
nous la croyons irreprochable, si on veut bien
1’entendre, et remarquer que Descartes ne parle
que des Fins totales de Dieu. Sans doute, le
soleil par exemple, et les etoiles, ont ete faits
pour 1’homme, dans ce sens, que Dieu, en les
creant, a eu en vue Futilite de I’homme ; et cette
utility a ete sa fin. Mais cette utilite a-t-elle
ete 1’unique fin de Dieu ? Croit-on qu’en lui
attribuant d’autres fins, on affoibliroit la re-
connoissance de I’homme, et 1’obligation ou il
est de louer et de benir Dieu dans toutes ses
oeuvres ? Les auteurs de la vie spirituelle, les
plus mystiques meme, et les plus accr^dites, ne
1’ont pas cru.”—(M. 1’Abbe Emery, Editor of
the Thoughts of Descartes upon Religion and Mo¬
rals, Paris, 1811, p. TO.)
As to the unqualified charge of atheism, which
has been brought by some French ecclesiastics
against all of their countrymen that have pre¬
sumed to differ from the tenets of the Catholic
church, it will be admitted, with large allow¬
ances, by every candid Presbyterian, when it is
recollected that something of the same illiberali-
ty formerly existed under the comparatively
enlightened establishment of England. In the
present times, the following anecdote would ap¬
pear incredible, if it did not rest on the unques¬
tionable testimony of Dr Jortin: “ I heard Dr
B. say in a sermon, if any one denies the unin¬
terrupted succession of bishops, I shall not
scruple to call him a downright atheist. This,
when I was young (Jortin adds), was sound,
orthodox, and fashionable doctrine.”—(Tracts,
Yol. I. p. 486.)2
How far the effects of that false philosophy of
which Grimm’s correspondence exhibits so dark
and so authentic a picture, were connected with
the awful revolution which soon after followed,
it is not easy to say. That they contributed
greatly to blacken its atrocities, as well as to re¬
volt against it the feelings of the whole Chris¬
tian world, cannot be disputed. The experi¬
ment was indeed tremendous, to set loose the
passions of all classes of men from the restraints
attention, as it contains some very remarkable marginal notes on the Christianisme Devoile, copied from Voltaire’s own
handwriting.
Since writing the above note, I have seen the Memoirs of M. Suard, by M. Garat (Paris, 1820), in which the biographer,
whose authority on this point is perfectly decisive, ascribes with confidence to Baron d’Holbach the Systeme de la Nature,
and also a work entitled La Morale et La Legislation Universelle (Yol. I. pp. 210, 211.)
According to the same author, the Baron d’Holbach was one of Diderot’s proselytes—(LUd. p. 208.) His former creed,
it would appear, had been very different.
1 And yet Diderot, in some of his lucid intervals, seems to have thought and felt very differently. See Note TT.
2 See Note U U.
Of the levity and extravagance with which such charges have sometimes been brought forward, we have a remarkable
instance in a tract entitled Athei Detecti, by a very learned Jesuit Father Hardouin ; (see his Opera Varia Posthuma, Amsterdam,
1733, in fob) where, among a number of other names, are to be found those of Jansenius, Descartes, Malebranche, Arnauld,
Nicole, and Pascal. Large additions on grounds equally frivolous, have been made in later times, to this list, by authors,
who having themselves made profession of Atheism, were anxious, out of vanity, to swell the number of their sect. Of
this kind was a book published at Paris, under some of the revolutionary governments, by Pierre Sylvain Marechal, en¬
titled Dictionnaire des Athecs. Here we meet with the names of St Chrysostom, St Augustin, Pascal, Bossuet, Fenelon,
Bellarmin, Labruyere, Leibnitz, and many others not less unexpected. This book he is said to have published at the
suggestion of the celebrated astronomer Lalande, who afterwards published a supplement to the Dictionary, supplying the
omissions of the author. See the Biographic Universelle, articles Marechal, Lalande.
DISSERTATION FIRST.
183
imposed by religious principles; and the result
exceeded, if possible, what could have been an¬
ticipated in theory. The lesson it has afforded
has been dearly purchased; hut let us indulge
the hope that it will not he thrown away on the
generations which are to come.
A prediction, which Bishop Butler hazarded
many years before, does honour to his political
sagacity, as well as to his knowledge of human
nature; that the spirit of irreligion would pro¬
duce, some time or other, political disorders, si¬
milar to those which arose from religious fana¬
ticism in the seventeenth century.1 * *
Nearly about the time that the Encyclopedie
was undertaken, another set of philosophers,
since known by the name of Economists, formed
themselves into an association for the purpose of
enlightening the public on questions of political
economy. The object of their studies seemed
widely removed from all abstract discussion;
but they had, nevertheless, a metaphysical sys¬
tem of their own, which, if it had been brought
forward with less enthusiasm and exaggeration,
might have been useful in counteracting the
gloomy ideas then so generally prevalent about
the order of the universe. The whole of their
theory proceeds on the supposition that the ar¬
rangements of nature are wise and benevolent,
and that it is the business of the legislator to
study and co-operate with her plans in all his
own regulations. With this principle, another
was combined, that of the indefinite improve¬
ment of which the human mind and character
are susceptible; an improvement which was re¬
presented as a natural and necessary consequence
of wise laws, and which was pointed out to le¬
gislators as the most important advantage to he
gained from their institutions.
These speculations, whatever opinion may he
formed of their solidity, are certainly as remote
as possible from any tendency to atheism, and
still less do they partake of the spirit of that
philosophy which would level man with the
brute creation. With their practical tendency
in a political view we are not at present concern¬
ed; hut it would he an unpardonable omission,
after what has been just said of the metaphysi¬
cal theories of the same period, not to mention
the abstract principles involved in the Economi¬
cal System, as a remarkable exception to the ge¬
neral observation. It may he questioned, too,
if the authors of this system, by incorporating
their ethical views with their political disquisi¬
tions, did not take a more effectual step towards
discountenancing the opinions to which they were
opposed, than if they had attacked them in the
way of direct argument.8
On the metaphysical theories which issued from
the French press during the latter half of the
last century, I do not think it necessary for me
to enlarge, after what I have so fully stated in
some of my former publications. To enter into
details with respect to particular works would
be superfluous, as the remarks made upon any
one of them are nearly applicable to them all.
The excellent writings of M. Prevost, and of
M. Begerando, will, it is to he hoped, gradually
introduce into France a sounder taste in this
branch of philosophy.5 At present, so far as I
am acquainted with the state of what is called
! “ Is there no danger that all this may raise somewhat like that levelling spirit, upon atheistical principles, which in
the last age, prevailed upon enthusiastic ones ? Not to speak of the possibility, that different sorts of people may unite in
it upon these contrary principles.”—(Sermon preached before the House of Lords, January 30, 1741.)
As the fatal effects of both these extremes have, in the course of the two last centuries, been exemplified on so gigantic
a scale in the two most civilised countries of Europe, it is to be hoped that mankind may in future derive some salutary
admonitions from the experience of their predecessors. In the meantime, from that disposition common both to the higher
and lower orders to pass suddenly from one extreme to another, it is at least possible that the strong re-action produced by
the spirit of impiety during the French He volution may, in the first instance, impel the multitude to something approach¬
ing to the puritanical fanaticism and frenzy of the Cromwellian Commonwealth.
2 For some other observations on the Ethical principles assumed in the Economical System, see Elements of the Philosophy
of the Human Mind, Vol. II. Chap. iv. Sect. 6. § 1. towards the end.
3 Some symptoms of such a reformation are admitted already to exist, by an author decidedly hostile to all philosophical
systems. “ Bacon, Locke, Condillac, cherchoient dans nos sens I’origine de nos ide'es ; Helvetius y a trouve nos idees elles-
rnemes. Juger, selon ce philosophe, n'est autre chose que sentir.* Aujourd’hui les bons esprits, eclaire's par les e've'nemens
I was somewhat surprised, in looking over very lately the Principia of Descartes, to find (what had formerly escaped
me), that the mode of speaking objected to in the above paragraph may plead in its favour the authority of that philosopher:
“ Cogitationis nomine, intelligo ilia omnia, quae nobis consciis in nobis fiunt, quatenus eorum in nobis conscientia est: Atque
184
PRELIMINARY DISSERTATIONS.
Ideologic in that country, it does not appear to
me to furnish much matter either for the in¬
struction or amusement of my readers.
The works of Rousseau have, in general, too
slight a connection with metaphysical science, to
come under review in this part of my discourse.
But to his Emile, which has been regarded as a
supplement to Locke’s Tveotise on Education,
some attention is justly due, on account of vari¬
ous original and sound suggestions on the ma¬
nagement of the infant mind* which, among
many extravagancies, savouring strongly both
of intellectual and moral insanity, may he
gathered by a sober and discriminating inquirer.
The estimate of the merits of this work, formed
by Mr Gray, appears to me so just and impar¬
tial, that I shall adopt it here without a com¬
ment.
“ I doubt” (says he, in a letter to a friend)
“ you have not yet read Rousseau’s Emile.
Every body that has children should read it more
than once; for though it abounds with his usual
glorious absurdity, though his general scheme
of education he an impracticable chimera, yet
there are a thousand lights struck out, a thousand
important truths better expressed than ever they
were before, that may be of service to the wisest
men. Particularly, I think he has observed
children with more attention, knows their mean¬
ing, and the working of their little passions,
better than any other writer. As to his religi¬
ous discussions, which have alarmed the world,
and engaged their thoughts more than any other
parts of his book, I set them all at nought, and
wish they had been omitted.”—(Gray’s Works
by Mason, Letter 49.)
The most valuable additions made by French
writers to the Philosophy of the Human Mind
are to be found, not in their systematical trea¬
tises on metaphysics, but in those more popu¬
lar compositions, which, professing to paint
the prevailing manners of the times, touch
occasionally on the varieties of intellectual
character. In this most interesting and im¬
portant study, which has been hitherto almost
entirely neglected in Great Britain,1 France
must be allowed not only to have led the way,
but to remain still unrivalled. It would be
endless to enumerate names; hut I must not
pass over those of Vauvenargues2 and Du-
sur la secrete tendance de toutes ces opinions, lea ont soumises a un examen plus severe. La transformation des sensations
en idees ne paroit plus qu’un mot vide de sens. On trouve que Vhomme statue ressemble un peu trop a Vhomme machine, et
Condillac est modifie' ou meme combattu sur quelques points, par tous ceux qui s’en servent encore dans 1’enseignement
phiiosophique.”'—(Recherches Philosophiques, &[C. par M. de Bonald, Tome I. pp. 34. 3o.)
1 Manv precious hints connected with it may, however, be collected from the writings of Lord Bacon, and a few from
those of Mr Locke. It does not seem to have engaged the curiosity of Mr Hume in so great a degree as might have been
expected from his habits of observation and extensive intercourse with the world. The objects of Dr Reid’s inquiries led
him into a totallv different track. . , . . „ . ,
Among German writers, Leibnitz has occasionally glanced with a penetrating eye at the varieties of genius; and it were
to be wished that he had done so more frequently. How far his example has been followed by his countrymen in later
times, I am unable to judge, from my ignorance of their language. ^ t _ u
A work expressly on this subject was published by a Spanish physician (Huarte) in the seventeenth century. A T rench
translation of it, printed at Amsterdam in 1672, is now lying before me. It is entitled, Rramen des Esprits pour les Sciences.
Oil se montrent les differences des Esprits, qui se trouvent parmi les hommes, et d quel genre de Science chacun est propre en par-
ticulier. The execution of this work certainly falls far short of the expectations raised by the title; but, allowances being
made for the period when it was written, it is by no means destitute of merit, nor unworthy of the attention of those who
may speculate on the subject of Education. For some particulars about its contents, and also about the author, see Bayle s
Dictionary, Art. Hudrte; and The Spectator, No. 30. n .
2 The Marquis de Yauvenargues, author of a small volume, entitled Introduction d la Connoissance de l Esprit Humain.
He entered into the army at the age of eighteen, and continued to serve for nine years ; when, having lost his health irre¬
coverably, inconsequence of the fatigues he underwent in the memorable retreat from Prague, in December 1742, he re¬
solved to quit his profession, in the hope of obtaining some diplomatic employment better suited to his broken constitution.
Soon after, he was attacked by the small-pox, which unfortunately turned out of so malignant a kind, as to disfigure his
countenance, and deprive him almost totally of sight. He died in 1747, at the age of thirty-two. T he small volume above
mentioned was published the year before his death. It bears everywhere the marks of a powerful, original, and elevated
mind; and the imperfect education which the author appears to have received gives it an additional charm, as the genuine
result of his own unsophisticated reflections.
Marmontel has given a most interesting picture of his social character : “ En le lisant, je crois encore 1’entendre, et je ne
ita non modo intelligere, velle, imaginari, sed etiam sentire, idem est hie quod cogitare.”—(Princ. Phil. p. 2.) Dr Reid,
too, has said that “ the sensation of colour is a sort of thought” (Inquiry, Chap. vi. § 4.); but no names, how great soever,
can sanction so gross an abuse of language.
After all, there is some difference between saying, that sensation is a sort of thought, and that thought is a sort of sen¬
sation.
DISSERTATION FIRST.
185
clos.1 Nor can I forbear to remark, in justice
to an author whom I have already very
freely censured, that a variety of acute and
refined observations on the different modifi¬
cations of genius may be collected from the
writings of Helvetius. The soundness of some
of his distinctions may perhaps be question¬
ed ; but even his attempts at classification may
serve as useful guides to future observers, and
may supply them with a convenient nomencla¬
ture, to which it is not always easy to find cor¬
responding terms in other languages. As ex¬
amples of this, it is sufficient to mention the fol¬
lowing phrases: Esprit juste, Esprit borne, Es¬
prit etendu, Esprit fin, Esprit delie, Esprit de
lumiere. The peculiar richness of the French
tongue in such appropriate expressions (a cir¬
cumstance, by the way, which not unfrequently
leads foreigners to overrate the depth of a talka¬
tive Frenchman) is itself a proof of the degree
of attention which the ideas they are meant to
convey have attracted in that country among the
higher and more cultivated classes.
The influence, however, of the philosophical
spirit on the general habits of thinking among
men of letters in France, was in no instance dis¬
played to greater advantage, than in the nume¬
rous examples of theoretical or conjectural history,
which appeared about the middle of last century.
I have already mentioned the attempts of Con¬
dillac and others, to trace upon this plan the
first steps of the human mind in the invention
of language. The same sort of speculation has
been applied with greater success to the mecha¬
nical and other necessary arts of civilised life ;8
and still more ingeniously and happily to the
different branches of pure and mixed mathema¬
tics. To a philosophical mind, no study certain¬
ly can be more delightful than this species of
history; but as an organ of instruction, I am
not disposed to estimate its practical utility so
highly as D’Alembert. It does not seem to me
at all adapted to interest the curiosity of novices:
nor is it so well calculated to engage the atten¬
tion of those who wish to enlarge their scientific
knowledge, as of persons accustomed to reflect
on the phenomena and laws of the intellectual
world.
Of the application of theoretical history, to
account for the diversities of laws and modes
of government among men, I shall have occasion
afterwards to speak. At present I shall only
remark the common relation in which all such
researches stand to the Philosophy of the Hu¬
man Mind, and their common tendency to ex¬
pand and to liberalise the views of those who are
occupied in the more confined pursuits of the
subordinate sciences.
After what has been already said of tbe
general tone of French philosophy, it will not
appear surprising, that a system so mystical and
spiritual as that of Leibnitz never struck its
roots deeply in that country. A masterly out¬
line of its principles was published by Madame
du Chatelet, at a period of her life when she
was an enthusiastic admirer of the author; and
a work on such a subject, composed by a lady
of her rank and genius, could not fail to pro¬
duce at first a very strong sensation at Paris;
but not long after, she herself abandoned the
sais si sa conversation n’avait pas meme quelque chose de plus animd, de plus delicat que ses divins ecrits.” And, on a
different occasion, he speaks of him thus: “ Doux, sensible, compatissant, il tenait nos ames dans ses mains. Une serdnite
inalterable derobait ses douleurs aux yeux de I’amitid. Pour soutenir I’adversite, on n’avoit besoin que de son exemple ;
et temoin de Pegalite de son ame, on n’osait etre malheureux avec lui.” See also an eloquent and pathetic tribute to the
genius and worth of Vauvenargues, in Voltaire’s Eloge Funtbre de$ Officiers qui sont marts dans la Guerre de 1741.
If the space allotted to him in this note should be thought to exceed what is due to his literary eminence, the singular
circumstances of his short and unfortunate life, and the deep impression which his virtues, as well as his talents, appear to
have left on the minds of all who knew him, will, I trust, be a sufficient apology for my wish to add something to the cele¬
brity of a name, hitherto, I believe, very little known in this country.
1 The work of Duclos, here referred to, has for its title, Considerations sur les Mceurs de ce Siecle. Gibbon’s opinion of
this book is, I think, not beyond its merits : “ L’ouvrage en general est bon. Queiques chapitres (le rapport de I’esprit et
du caractere) me paroissent excellens.”—f Extrait du Journal.)
1 have said nothing of La Rochefoucauld and La Bruyere, as their attention was chiefly confined to manners, and to mo¬
ral qualities. Yet many of their remarks show, that they had not wholly overlooked the diversities among men in point of
intellect. An observer of sagacity equal to their’s might, I should think, find a rich field of study in this part of human
nature, as well as in the other.
2 Particularly by the President de Goguet, in his learned work, entitled, “ De I'Origine des Lois, des Arts, et des Sciences,
et de lews Progres chez les Anciens Peuplcs." Paris, ITHli.
DISS. I. PART II. 2 A
186
PRELIMINARY DISSERTATIONS.
German philosophy, and became a zealous
partizan of the Newtonian school. She even
translated into French, and enriched with a
commentary, the Principia of Newton ; and by
thus renouncing her first faith, contributed more
to discredit it, than she had previously done to
bring it into fashion. Since that time, Leibnitz
has had few, if any, disciples in France, al¬
though some of his peculiar tenets have oc¬
casionally found advocates there, among those
who have rejected the great and leading doc¬
trines, by which his system is more peculiarly
characterised. His opinions and reasonings in
particular, on the necessary concatenation of all
events, both physical and moral (which accord¬
ed hut too well with the philosophy professed
by Grimm and Diderot), have been long incor¬
porated with the doctrines of the French ma¬
terialists, and they have been lately adopted
and sanctioned, in all their extent, by an au¬
thor, the unrivalled splendour of whose ma¬
thematical genius may be justly suspected, in
the case of some of his admirers, to throw a
false lustre on the dark shades of his philosophi¬
cal creed.1
Notwithstanding, however, this important
and unfortunate coincidence, no two systems
can well be imagined more strongly contrasted
on the whole, than the lofty metaphysics of
Leibnitz, and that degrading theory concerning
the origin of our ideas, which has been fashion¬
able in France since the time of Condillac. In
proof of this, I have only to refer to the account
of both, which has been already given.
The same contrast, it would appear, still con¬
tinues to exist between the favourite doctrines
of the German and of the French schools. “ In
the French empiricism (says a most impartial,
as well as competent judge, M. Ancillon), the
faculty of feeling, and the faculty of knowing,
1 “ Les £;venemens actuels ont avec les precedens une liaison fondee sur le principe Evident, qu’une chose ne peat pas
commence!' d’etre, sans une cause qui la produise. Cet axiome, connu sous le nom de principe de la raison snffisante, s etend
aux actions meme que Ton juge indifFe'rentes. La volonte la plus libre ne peut, sans un motif determinant, leur donner
naissance; car si, toutes les circonstances de deux positions etant exactement semblables, elle agissoit dans Pune ey s’ab-
stenoit d’agir dans Pautre, son choix seroit un effet sans cause ;* elle seroit alors, dit Leibnitz, le hazard aveugle des Lpicu-
riens. L’opinion contraire est une illusion de Pesprit qui perdant de vue les raisons fugitives du choix de la volonte dans
les choses indifferentes, se persuade qu’elle s’est determine'e d’elle meme et sans motifs.
“ Nous devons done envisager Petat pre'sent de Punivers comme Peffet de son etat anterieure, et comme la cause de celui
qui va suivre. Une intelligence qui pour un instant donne connoitroit toutes les forces dont la nature est^ animee, et la
situation respective des etres qui la composent, si d’ailleurs elle etoit assez vaste pour soumettre ces donnees a 1 analyse,
embrasseroit dans la meme formule, les mouveinens des plus grands corps de Punivers et ceux de plus leger atome.
ne seroit incertain pour elle, et Pavenir comme le passe, seroit present a ses yeux.”—(Essai Philosophique sur les Probabilites,
par Laplace.) _ . .
Is not this the very spirit of the Theodiccea of Leibnitz, and, when combined with the other reasonings in the Essay on
Probabilities, the very essence of Spinozism? _ _ .
This, indeed, is studiously kept by the author out of the reader’s view ; and hence the facility with which some of his
propositions have been admitted by many of his mathematical disciples, who, it is highly probable, were not aware of the
consequences which they necessarily involve. _ _ ,
I cannot conclude this note without recurring to an observation ascribed in the above quotation from Laplace to Leib¬
nitz, “ that the blind chance of the Epicureans involves the supposition of an effect taking place without a cause. Phis, I
apprehend, is a very incorrect statement of the philosophy taught by Lucretius, which nowhere gives the slightest coun¬
tenance to such a supposition. The distinguishing tenet of this sect was, that the order of the universe does not imply the
existence of intelligent causes, but may be accounted for by the active powers belonging to the atoms of matter; which ac¬
tive powers, being exerted through an indefinitely long period of time, might produce, nay, must have, produced, exactly
such a combination of things, as that with which we are surrounded. This, it is evident, does not call in question the ne¬
cessity of a cause to produce every effect, but, on the contrary, virtually assumes the truth of that axiom. It only excludes
from these causes the attribute of intelligence. It is in the same way when I apply the words blind chance (hazard aveugle)
to the throw of a die, I do not mean to deny that I am ultimately the cause of the particular event that is to take place; but
only to intimate that I do not here act as a designing cause, in consequence of my ignorance of the various accidents to
which the die is subjected, while shaken in the box. If I am not mistaken, this Epicurean Theory approaches very nearly
to the scheme, which it is the main object of the Essay on Probabilities to inculcate; and, therefore,, it was not quite fair .in
Laplace to object to the supposition of man’s free agency, as favouring those principles which he himself was labouring in¬
directly to insinuate.
From a passage in Plato’s Sophist, it is very justly inferred by Mr Gray, that, according to the common opinion then en¬
tertained, “ the creation of things was the work of blind unintelligent matter ; whereas the contrary was the result of phi¬
losophical reflection and disquisition believed by a few people only.”—(Gray's Works by Matthias, Yol. II. p. 414.) On
the same subject, see Smith’s Posthumous Essays, p. 106.
* The impropriety of this language was long ago pointed out by Mr Hume. “ They are still more frivolous who say,
that every effect must have a cause, because it is implied in the very idea of effect. Every effect necessarily presupposes
a cause; effect being a relative term, of which cause is the co-relative. The true state of the question is, whether every
object, which begins to exist, must owe its existence to a cause?”—( Treatise of Human Nature, Vol. I. p. 1 47-)
DISSERTATION FIRST.
187
are one and the same. In the new philosophy
of Germany, there is no faculty of knowing,
but reason. In the former, taking our departure
from individuals, we rise by degrees to ideas, to
general notions, to principles. In the latter,
beginning with what is most general, or rather
with what is universal, we descend to individu¬
al existences, and to particular cases. In the
one, what we see, what we touch, what we feel,
are the only realities. In the other, nothing is
real but what is invisible and purely intellectual.”
“ Both these systems (continues M. Ancillon)
result from the exaggeration of a sound prin¬
ciple. They are both true and both false in
part; true in what they admit, false in what
they reject. All our knowledge begins, or ap¬
pears to begin, in sensation; but it does not fol¬
low from this that it is all derived from sensa¬
tion, or that sensation constitutes its whole
amount. The proper and innate activity of the
mind has a large share in the origin of our re¬
presentations, our sentiments, our ideas. Reason
involves principles which she does not borrow
from without, which she owes only to herself,
which the impressions of the senses call forth
from their obscurity, but which, far from owing
their origin to sensations, serve to appreciate
them, to judge of them, to employ them as instru¬
ments. It would be rash, however, to conclude
from hence, that there is no certainty but in reason,
that reason alone can seize the mystery of exist¬
ences, and the intimate nat ure of beings, and that
experience is nothing but a vain appearance,
destitute of every species of reality.”1
With this short and comprehensive estimate
of the new German philosophy, pronounced by
one of the most distinguished members of the
Berlin Academy, I might perhaps be pardoned
for dismissing a subject, with which I have, in
some of my former publications, acknowledged
myself (from my total ignorance of the German
language) to be very imperfectly acquainted;
but the impression which it produced for a few
years in England (more particularly while our
intercourse with the Continent was interrupted),
makes it proper for me to bestow on it a little
more notice in this Dissertation, than I should
otherwise have judged necessary or useful.
SECTION VII.
Kant and other Metaphysicians of the New German School.2
The long reign of the Leibnitzian Philosophy degree, to the zeal and ability with which it was
in Germany was owing, in no inconsiderable taught in that part of Europe, for nearly half a
1 Melanges de Litterature et de Philosophic, par F. Ancillon, Preface, (k Paris, 1809.) The intimacy of M. Ancillon’s
literary connections both with France and with Germany entitle his opinions on the respective merits of their philosophi¬
cal systems to peculiar weight. If he anywhere discovers a partiality for either, the modest account which he gives of
himself would lead us to expect his leaning to be in favour of his countrymen. “ Placd entre la France et PAllemagne,
appartenant a la premiere par la langue dans laquelle je hasarde d’dcrire, a la seconde par ma naissance, mes etudes, mes
principes, mes affections, et j’ose le dire, par la couleur de ma pensde, je desirerois pouvoir servir de mediateur litte'raire,
ou d’interprete philosophique entre les deux nations.”
In translating from M. Ancillon the passage quoted in the text, I have adhered as closely as possible to the words of
the original; although I cannot help imagining that I could have rendered it still more intelligible to the English reader
by laying aside some of the peculiarities of his German phraseology. My chief reason for retaining these, ivas to add
weight to the strictures which a critic, so deeply tinctured with the German habits of thinking and of writing, has offered,
on the most prominent faults of the systems in which he had been educated.
* My ignorance of German would have prevented me from saying anything of the philosophy of Kant, if the extraor¬
dinary pretensions with which it was at first brought forward in this island, contrasted with the total oblivion into which
it soon after very suddenly fell, had not seemed to demand some attention to so wonderful a phenomenon in the literary
history of the eighteenth century. My readers will perceive that I have taken some pains to atone for my inability to
read Kant’s works in the original, not only by availing myself of the Latin version of Born, but by consulting various com¬
ments on them which have appeared in the English, French, and Latin languages. As commentators, however, and even
translators, are not always to be trusted to as unexceptionable interpreters of their authors’ opinions, my chief reliance has
been placed on one of Kant’s own compositions in Latin ; his Dissertation De Mundi Sensibilis atque Intelligibilis Forma et
Prineipiis, which he printed as the subject of a public disputation, when he was candidate for a Professorship in the Uni-
188
PRELIMINARY DISSERTATIONS.
century, by his disciple Wolfius,1 a man of little
genius, originality, or taste, but whose exten¬
sive and various learning, seconded by a metho¬
dical head,* and by an incredible industry
and perseverance, seems to have heen peculiarly
fitted to command the admiration of his country¬
men. Wolfius, indeed, did not profess to follow
implicitly the opinions of his master, and, on
some points, laid claim to peculiar ideas of his
own; but the spirit of his philosophy is essen¬
tially the same with that of Leibnitz,5 and the
particulars in which he dissented from him are
too trifling to deserve any notice in the history
of literature.4
The high reputation so long maintained by
Wolfius in Germany suggested, at different times,
to the book-makers at Paris, the idea of intro¬
ducing into France the philosophy which he
taught. Hence a number of French abridg¬
ments of his logical and metaphysical writings.
But an attempt, which had failed in the hands
of Madame de Chatelet, was not likely to suc¬
ceed with the admirers and ahridgers of Wol¬
fius.5
versity of Koenigsberg. It is far from being improbable, after all, that I may, in some instances, have misapprehended his
meaning, but I hope I shall not be accused of wilfully misrepresenting it. Where my remarks are borrowed from other
writers,”l have been careful in referring to my authorities, that my reader may judge for himself of the fidelity of my
statements. If no other purpose, therefore, should be answered by this part of my work, it may at least be of use by call¬
ing forth some person properly qualified to correct any mistakes into which I may involuntarily have fallen ; and, in the
meantime, may serve to direct those who are strangers to German literature, to some of the comments on this philosophy
which have appeared in languages more generally understood in this country.
1 Born 1679. Died 1?54.
2 The display of method, however, so conspicuous in all the works of Wolfius, will often be found to amount to little
more than an aukward affectation of the phraseology and forms of mathematics, in sciences where they contribute nothing
to the clearness of our ideas, or the correctness of our reasonings. This affectation, which seems to have been well adapted
to the taste of Germany at the time when he wrote, is now one of the chief causes of the neglect into which his writings
have fallen. Some of them may still be usefully consulted as dictionaries, but to read them is impossible. They amount
to about forty quarto volumes, twenty-three of which are in Latin, the rest in German.
In his own country the reputation of Wolfius is not yet at an end. In the preface to Kant’s Critique of Pure Reason, he
is called “ Summus omnium dogmaticorum Philosophus.”—(Kantii Opera ad Philosophiarn Criticam, Yol. I. Praef. Auctoris
Posterior, p. xxxvi. Latine Yertit. I'red. Born. Lipsiae, 1796.) And by one of Kant’s best commentators his name is
advantageously contrasted with that of David Hume: “ Est autem scientifica methodus aut dogmatica, aut sceptica.
Primi generis autorem celeberrimum Wolfium, alterius Davidem Humium nominasse sat est.” (Expositio Philos. Criticoe.
Autore Conrado Friderico a Schmidt-Phiseldek. Hafniae, 1796.)
To the other merits of Wolfius it may be added, that he was one of the first who contributed to diffuse among his coun¬
trymen a taste for philosophical inquiries, by writing on scientific subjects in the German language. “ Were all Baron
Wolf’s other merits disputed, there is one (says Michaelis), which must incontestably be allowed him, his having added a
new degree of perfection to the German Tongue, by applying it to philosophy.”—(Dissertation on the Influence of Opinions on
Language, &c. English Translation, p. 27-)
3 On the great question of Free Will, Wolfius adopted implicitly the principles of the Theodicaea ; considering man
merely in the light of a machine; but (with the author of that work) dignifying this machine by the epithet spiritual. This
language, which is still very prevalent among German philosophers, may be regarded as a relic of the doctrines of Leibnitz
and of Wolfius ; and affords an additional proof of the difficulty of eradicating errors sanctioned by illustrious and popular
names.
When the system of Pre-established Harmony was first introduced by Wolfius into the University of Halle, it excited
an alarm which had very nearly been attended with fatal consequences to the professor. The following anecdote on the
subject is told by Euler: “ Lorsque du temps du feu Hoi de Prusse, M. Wolf enseignoit a Halle le systeme de 1’Har-
monie Pre-etablie, le Boi s’informa de cette doctrine, qui faisoit grand bruit alors ; et un courtisan repondit a sa Majeste,
que tous les soldats, selon cette doctrine, n’etoient que des machines; que quand il en desertoit, c’etoit une suite ndcessaire
de leur structure, et qu’on avoit tort par consequent de les punir, comme on 1’auroit si on punissoit une machine pour avoir
produit tel ou tel mouvement. Le Hoi se facha si fort sur ce rapport, qu’il donna ordre de chasser M. Wolf de Halle, sous
peine d’etre pendu s’il s’y trouvoit au bout de 24 heurs. Le philosophe se refugia alors a Marbourg, oil je lui ai parle peu
de temps apres (Lettres a une Princesse d'Allemagne, Lettre 84me.) We are informed by Condorcet, that some reparation
was afterwards made for this injustice by Frederic the Great—“ Le lloi de Prusse, qui necroit pas pourtant a 1’Harmonie
Pre-etablie, s’est empresse de rendre justice a Wolf des le premier jour de son regne.”
4 Among other novelties affected by Wolfius, was a new modification of the Theory of the Monads. A slight outline
of it, but quite sufficient, I should suppose, to gratify the curiosity of most readers, may be found in Euler’s Letters to a
German Princess.
5 To what was before remarked, of the opposition in matters of philosophy between the taste of the French and that of
the Germans, I shall here add a short passage from an author intimately acquainted with the literature of both nations.
“ L’ecole Allemande reconnoit Leibnitz pour chef. Son fameux disciple Wolf regna dans les universites pendant pres
d'un demi siecle avec une autorite non contestee. On connoit en France cette philosophic par un grand nombre d’abreges
dont quelque-uns sont faits par des auteurs qui seuls auroient suffi pour lui donner de la celebrite.
“ Malgre 1’appui de tous ces noms, jamais en France cette philosophic ne s'est soutenue mtme quelques instans. La profondeur
apparente des idees, Pair d’ensemble et de systeme, n’ont jamais pu y suppleer a ce qui a paru lui manquer pour en faire
une doctrine solide et digne d’etre accueillie. Outre quelque defaut de clarte, qui probablement en a ecarte des esprits pour
qui cette qualite de style et de la pensee est devenue un heureux besoin, la forme sous laquelle elle se presente a rebute
bien des lecteurs. Quoi qu’aient pu faire les interpretes, il a toujours perce quelque chose de 1’appareil incommode qui
Pentoure a son origine. Condillac tourne plus d’une fois en ridicule ces formes et ce jargon scientifique, et il s’applique a
DISSERTATION FIRST.
189
From the time of Wolfius till the philosophy
of Kant began to attract general notice, I know
of no German metaphysician whose speculations
seem to have acquired much celebrity in the
learned world.1 Lambert® is perhaps the most
illustrious name which occurs during this inter¬
val. As a mathematician and natural philoso¬
pher, his great merits are universally known
and acknowledged, but the language in which
his metaphysical and logical works were written,
has confined their reputation within a compa¬
ratively narrow circle. I am sorry that I can¬
not speak of these from my own knowledge;
but I have heard them mentioned in terms of
the highest praise, by some very competent
judges, to whose testimony I am disposed to
give the greater credit, from the singular vein
of originality which runs through all his mathe¬
matical and physical publications.3
The Critique of Pure Reason (the most cele¬
brated of Kant’s metaphysical works) appeared
in 1781.4 The idea annexed to the title by the
author, is thus explained by himself: “ Criti-
cam rationis purse non dico censuram librorum
et Systematum, sed facultatis rationalis in uni-
versum, respectu cognitionum omnium, ad quas,
ab omni experientia libera, possit anniti, proinde
dijudicationem possibilitatis aut impossibilitatis
metaphysices in genere, constitutionemque turn
fontium, turn ambitus atque compagis, turn vero
terminorum illius, sed cuncta haec ex princi-
piis.” ( Kantii, Opera ad Pkilosophiam Criticam.,
Vol. I. Prsefatio Auctoris Prior, pp. 11, 12.) To
render this somewhat more intelligible, I shall
subjoin the comment of one of his intimate
friends,5 whose work, we are informed by Dr
Willich, had received the sanction of Kant him¬
self. “ The aim of Kant’s Critique is no less
than to lead Reason to the true knowledge of it¬
self ; to examine the titles upon which it founds
the supposed possession of its metaphysical
knowledge ; and by means of this examination,
to mark the true limits, beyond which it cannot
venture to speculate, without wandering into the
empty region of pure fancy.” The same author
adds, “ The whole Critique of Pure Reason is es¬
tablished upon this principle, that there is a free
reason, independent of all experience and sensation.”
montrer qu’ils ne sont pas plus propres a satisfaire la raison que le gout. Ilest au moins certain, que le lecteur Frangais let re¬
pousse par instinct, et qu'il y trouve un obstacle tree difficile d surmonter."—(Reflexions sur les (Euvres Posthumes d'Ailani Smith,
par M. Prevost de Geneve, a Paris, 1794.)
1 Madame de Stael mentions Lessing, Hemsterhuis, and Jacobi, as precursors of Kant in his philosophical career. She
adds, however, that they had no school, since none of them attempted to found any system; but they began the war
against the doctrines of the Materialists—(Allemagne, Tome III. p. 98.) I am not acquainted with the metaphysical
works of any of the three. Those of Hemsterhuis, who wrote wholly in French, were, I understand, first published in a
collected form at Paris, in 1792. He was son of the celebrated Greek scholar and critic, Tiberius Hemsterhusius, Profes¬
sor of Latin Literature at Leyden.
2 Born at Mulhausen in Alsace in 1728. Hied at Berlin in 1777*
3 The following particulars, with respect to Lambert’s literary history, are extracted from a Memoir annexed by M.
Prevost to his translation of Mr Smith’s Posthumous Works:—“ Get ingenieux et puissant Lambert, dont les mathema-
tiques, qui lui doivent beaucoup, ne purent epuiser les forces, et qui ne toucha aucun sujet de physique ou de philosophic
rationelle, sans le couvrir de lumiere. Ses lettres cosmologiques, qu’il ecrivit par forme de delassement, sont pleines d’idees
sublimes, entees sur la philosophie la plus saine et la plus savante tout-a-la-fois. II avoit aussi dresse sous le titre d'Archi-
tectonique un tableau des principes sur lesquels se fondent les connoissances humaines. Get ouvrage au jugement des hommes
les plus verses dans 1’etude de leur langue, n’est pas exempt d’obscurite. File peut tenir en partie a la nature du sujet.
11 est a regretter que sa logique, intitule Organon, ne soil traduite ni en Latin, ni en Francais, ni je pense en aucune
langue. Un extrait bien fait de cet ouvrage, duquel on e'carteroit ce qui repugne au gout national, exciteroit 1’attention
des philosophes, et la porteroit sur une multitude d’obje'ts qu’ils se sont accoutumes a regardgr avec indifference.”—(Pre¬
vost, Tome II. pp. 267, 268.)
In the article Lambert, inserted in the twenty-third volume of the Biographic Universelle (Paris 1819), the following ac¬
count is given of Lambert’s logic :—“ Wolf, d’apres quelques indications de Leibnitz, avoit retire de 1’oubli la syllogistique
d’Aristote, science que les scholastiques avoient tellement avilie que ni Bacon ni Locke n’avoient ose lui accorder un regard
d’inte'ret. II e'toit reserve d Lambert de la montrer sous le plus beau jour et dans la plus riche parure. C’est ce qu’il a
fait dans son Novum Organon, ouvrage qui est un des principaux titres de gloire de son auteur.” From the writer of this
article (M. Servois) we farther learn, that the Novum Organon of Lambert was translated into Latin from the German ori¬
ginal by a person of the name of Pfleiderer, and that this translation was in the hands of an English nobleman (the late
Earl of Stanhope) as lately as 1782. I quote the words of M. Servois, in the hope that they may attract some attention
to the manuscript, if it be still in existence. The publication of it would certainly be a most acceptable present to the
learned world. “ D’apres le conseil de Le Sage de Geneve, 1’ouvrage fut traduit en Latin par Pfleiderer, aux frais d’un
savant Italien; cette traduction passa, on ne sait comment, entre les mains de Milord Mahon, qui la possedoit encore en
1782; on ignore quel est son sort ulterieur.”
4 Kant was born at Koenigsberg, in Prussia, in 1724. Pie died in 1804.
h Mr John Schulze, an eminent divine at Koenigsberg, author of the Synopsis of the Critical Philosophy, translated by Dr
Willich, and inserted in his Elementary View of Kant's Works—(See pp. 42, 48.)
190
PRELIMINARY DISSERTATIONS.
When the Critique of Pure Reason first came
out, it docs not seem to have attracted much
notice,1 hut sucli has been its subsequent suc¬
cess, that it may be regarded, according to
Madame de Stael,8 “ as having given the impulse
to all that has been since done in Germany,
both in literature and in philosophy.”—(AUe-
magne, Vol. III. pp. 68, 69.)
“ At the epoch when this work was publish¬
ed (continues the same writer), there existed
among thinking men only two systems concern¬
ing the human understanding: The one, that of
Locke, ascribed all our ideas to our sensations;5
the other, that of Descartes and of Leibnitz, had
for its chief objects to demonstrate the spiritua¬
lity and activity of the soul, the freedom of the
will,4 and, in short, the whole doctrines of the
idealists Between these extremes rea-
1 II se passa quelque terns apres la premiere publication de la Critique dc la Pure Raisoji, sans qu’on fitbeaucoup d’attention
a ce livre, et sans que la plupart de philosophes, passione's pour 1’eclectisme, soupc;onassent seulement la grande revolution
que cet ouvrage et les productions suivantes de son auteur devoient operer dans la science.”—(Buhle, Hist, de la Phil.
Mod. Tom. VI. p. 573. Paris, 181G.)
As early, however, as the year 1783, the Philosophy of Kant appears to have been adopted in sowe of the German schools.
The ingenious M. Trembley, in a memoir then read before the Academy of Berlin, thus speaks of it:—“ La philosophic
de Kant, qui, a la honte de Vesprit humain, paroit avoir acquis tant de faveur dans certaines ecoles.”—(Essai sur les Prtjugls.
Reprinted at Neufchatel in 1790.)
We are farther told by Buhle, that the attention of the public to Kant’s Critique of Pure Reason was first attracted by an
excellent analysis of the work, which appeared in the General Gazette of Literature, and by the Letters on Kant's Philosophy,
which Reinhold inserted in the German Mercury.—(Buhi.e, Tom. VI. p. 573.) Of this last philosopher, who appears, in
the first instance, to have entered with enthusiasm into Kant’s views, and who afterwards contributed much to open the
eyes of his countrymen to the radical defects of his system, I shall have occasion to speak hereafter. Degerando, as well
as Buhle, bestows high praise not only on his clearness, but on his eloquence, as a writer in his own language. “ II a tra-
duit les oracles Kantiens dans une langue elegante, harmonieuse, et pure * * * II a su exprimer avec un langage eloquent,
des hides jusqu’alors inintelligibles,” &c—(Histoire Comparte, &c. Tom. II. p. 271.) That this praise is not undeserved I
am very ready to believe, having lately had an opportunity (through the kindness of my learned and revered friend Dr
Parr) of reading, in the Latin version of Fredericus Gottolb Born, lleinhold’s principal work, entitled Periculum Novoc
Theoriae Facultatis Reprocsentativae Humana;. In point of perspicuity, he appears to me to be greatly superior to Kant; and of
this I conceive myself to be not altogether incompetent to judge, as the Latin versions of both authors are by the same
hand.
2 The following quotation, from the advertisement prefixed to Madame de Stael’s posthumous work (Considerations sur
la Revolution Fraiifaise), will at once account to my readers for the confidence with which I appeal to her historical state¬
ments on the subject of Germany philosophy. Her own knowledge of the language was probably not so critically exact, as
to enable her to enter into the more refined details of the different systems which she has described ; but her extraordinary
penetration, joined to the opportunities she enjoyed of conversing with all that was then most illustrious in Germany, qua¬
lified her in an eminent degree to seize and to delineate their great outlines. And if, in executing this task, any consider¬
able mistakes could have been supposed to escape her, we may be fully assured, that the very accomplished person, to whose
revision we learn that her literary labours at this period of her life were submitted, would prevent them from ever meeting
the public eye. I except, of course, those mistakes into which she was betrayed by her admiration of the German school.
Of some of the most important of these, I shall take notice as I proceed; a task which I feel incumbent on me, as it is
through the medium of her book that the great majority of Fmglish readers have acquired all their knowledge of the new
German philosophy, and as her name and talents have given it a temporary consequence in this country which it could not
otherwise have acquired.
“ Le travail des e'diteurs s’est borne uniquement a la re'vision des e'preuves, et a la correction de ces legeres inexactitudes
de style, qui echappent a la vue dans le manuscrit le plus soigne. Ce travail e’est fait sous les yeux de M. A. W. de Schle-
gel, dont la rare superiorite d'esprit et de savoir justifie la confance avec laquelle Madame de Stacl le consultoit dans tons ses travaux
litteraires, autant que son honorable caractere merite I’estime et 1’amitie qu’elle n’a pas cesse d’avoir pour lui pendant une
liaison dc treize annecs."
If any further apology be necessary for quoting a French lady as an authority on German metaphysics, an obvious one is
suggested by the extraordinary and well merited popularity of her Allemagne in this country. I do not know, if, in any
part of her works, her matchless powers have been displayed to greater advantage. Of this no stronger proof can be given
than the lively interest she inspires, even when discussing such systems as those of Kant and of Fichte.
3 That this is a very incorrect account of Locke’s philosophy, has been already shown at great length; but in this mistake
Madame de Stael has only followed Leibnitz, and a very large proportion of the German philosophers of the present day.
“ The philosophy of sensation,” says Frederick Schlegel, “ which was unconsciously bequeathed to the world by Bacon, and
reduced to a methodical shape by Locke, first displayed in France the true immorality and destructiveness of which it is
the parent, and assumed the appearance of a perfect system of Atheism.”—(Lectures on the History of Literature, from the
German ot Fred. Schlegel. F.din. 1818, Vol. II. p. 22.) It is evident, that the system of Locke is here confounded with
that ot Condillac. May not the former be called the philosophy of rejlection, with as great propriety as the philosophy of
sensation ?
4 In considering Leibnitz as a partizan of the freedom of the will, Madame de Stael has also followed the views of many
German writers, who make no distinction between Materialists and Necessitarians, imagining, that to assert the spiritua¬
lity of the soul, is to assert its free agency- On the inaccuracy of these conceptions it would be superfluous to enlarge,
after what was formerly said in treating of the metaphysical opinions of Leibnitz.
In consequence ol this misapprehension, Madame de Stael, and many other late writers on the Continent, have been led
to employ, with a very exceptionable latitude, the word Idealist, to comprehend not only the advocates for the immateriality
of the mind, but those also who maintain the Freedom of the Human Will. Between these two opinions, there is certainly
DISSERTATION FIRST.
191
sou continued to wander, till Kant undertook
to trace the limits of the two empires; of the
senses and of the soul; of the external and of
the internal worlds. The force of meditation
and of sagacity, with which he marked these
limits, had not perhaps any example among his
predecessors.”—(Allemagne, Yol. III. pp. 70, 72.)
The praise bestowed on this part of Kant’s
philosophy, by one of his own pupils, is not less
warm than that of Madame de Stael. I quote
the passage, as it enters into some historical de¬
tails which she has omitted, and describes more
explicitly than she has done one of the most im¬
portant steps, which Kant is supposed by his
disciples to have made beyond his predecessors.
In reading it, some allowances must be made for
the peculiar phraseology of the German school.
£t Kant discovered that the intuitive faculty of
man is a compound of very dissimilar ingre¬
dients ; or, in other words, that it consists of
parts very different in their nature, each of which
performs functions peculiar to itself; namely, the
sensitive faculty, and the understanding 
Leibnitz, indeed, had likewise remarked the
distinction subsisting between the sensitive facul¬
ty and the understanding; but he entirely over¬
looked the essential difference between their
functions, and was of opinion that the faculties
differed from one another only in degree 
In the works of the English and French philo¬
sophers, we find this essential distinction be¬
tween the sensitive and the intellectual facul¬
ties, and their combination towards producing
one synthetical intuition, scarcely mentioned.
Locke only alludes to the accidental limitations
of both faculties; but to inquire into the essen¬
tial difference between them does not at all oc¬
cur to him This distinction, then, be¬
tween the sensitive and the intellectual facul¬
ties, forms an essential feature in the philosophy
of Kant, and is, indeed, the basis upon which
most of his subsequent inquiries are establish¬
ed.”—(Elements of the Crit. Phil, by A. F. M.
Willich, M. D. pp. 68, 69, 70.)
It is a circumstance not easily explicable, that,
in the foregoing historical sketch, no mention is
made of the name of Cudworth, author of the
treatise on Eternal and Immutable Morality ; a
book which could scarcely fail to be known, be¬
fore the period in question, to every German
scholar, by the admirable Latin version of it
published by Dr Mosheim.1 In this treatise,
no necessary connection; Leibnitz, and many other German metaphysicians, denying the latter with no less confidence
than that with which they assert the former.
In England, the word Idealist is most commonly restricted to such as (with Berkeley) reject the existence of a material
world. Of late, its meaning has been sometimes extended (particularly since the publications of lleid) to all those who i-e-
tain the theory of Descartes and Locke, concerning the immediate objects of our perceptions and thoughts, whether they
admit or reject the consequences deduced from this theory by the Berkeleians. In the present state of the science, it
would contribute much to the distinctness of our reasonings were it to be used in this last sense exclusively.
There is another word to which Madame de Stael and other writers on the German philosophy annex an idea peculiar
to themselves ; I mean the word experimental or empirical. This epithet is often used by them to distinguish what thev
call the philosophy of Sensations, from that of Plato and of Leibnitz. It is accordingly generally, if not always, employed
by them in an unfavourable sense. In this country, on the contrary, the experimental or inductive philosophy of the hu¬
man mind denotes those speculations concerning mind, which, rejecting all hypothetical theories, rest solely on phenomena
for which we have the evidence of consciousness. It is applied to the philosophy of Reid, and to all that is truly valuable
in the metaphysical works of Descartes, Locke, Berkeley, and Hume.
Nor are the words, experimental and empirical, by any means synonymous in our language. The latter word is now al¬
most exclusively appropriated to the practice of Medicine ; and when so understood always implies a rash and unphiloso-
phical use of Experience. “ The appellation Empiric,” says the late Dr John Gregory, “is generally applied to one who,
from observing the effects of a remedy in one case of a disease, applies it to all the various cases of that distemper.” The
same remark may be extended to the word Empirique in the French language, which is very nearly synonymous with
Charlatan. In consequence of this abuse of terms, the epithet experimental, as well as empirical, is seldom applied by foreign
writers to the philosophy of Locke, without being intended to convey a censure.
1 The first edition of this translation was printed as early as 1732. From Buhle’s History of Modern Philosophy (a work
which did not fall into my hands till long after this section was written), I find that Cudworth’s Treatise of Immutable Mo¬
rality is now not only well known to the scholars of Germany, but that some of them have remarked the identity of the
doctrines contained in it with those of Kant. “ Meiners, dans son histoire generale de PEthique, nie que le systeme
morale de Cudworth soit identique avec celui de Platon, et pretend au contraire, ‘ que les principes considerds comme ap-
partenans de la mani'ere la plus speciale a la morale de Kant, etaient enseignes il y a deja plusieurs generations par I’ecole
du philosophe Anglais.”—{Hist, de la Phil. Moderne, Tom. III. p. 577-) In opposition to this, Buhle states his own decid¬
ed conviction, “ qu’ aucune des idees de Cudworth ne se rapproche de celles de Kant.”—{Ibid.) How far this conviction is
well founded, the passage from Cudworth, quoted in the text, will enable my readers to judge for themselves.
That Cudworth has blended with his principles a vein of Platonic mysticism, which is not to be found in Kant, is un¬
deniable ; but it does not follow from this, that none of Kant’s leading ideas are borrowed from the writings of Cudworth.
The assertion of Buhle, just mentioned, is the more surprising, as he himself acknowledges that “ la philosophic
192
PRELIMINARY DISSERTATIONS.
Cudworth is at much pains to illustrate the Pla¬
tonic doctrine concerning the difference between
sensation and intellection ; asserting that 44 some
ideas of the mind proceed not from outward
sensible objects, but arise from the inward ac¬
tivity of the mind itselfthat 44 even simple
corporeal things, passively perceived by sense,
are known and understood only by the active
power of the mind and that, besides A/cr^^ara
and lavras [Mara, there must he Novara or intel¬
ligible ideas, the source of which can be traced
to the understanding alone.1
In the course of his speculations on these sub¬
jects, Cudworth has blended, with some very
deep and valuable discussions, several opinions
to which I cannot assent, and not a few propo¬
sitions which I am unable to comprehend; hut
he seems to have advanced at least as far as
Kant, in drawing the line between the provin¬
ces of the senses and of the understanding; and
although not one of the most luminous of our
English writers, he must he allowed to he far
superior to the German metaphysician, both in
point of perspicuity and of precision. A later
writer, too, of our own country (Dr Price), a
zealous follower both of Plato and of Cudworth,
afterwards resumed the same argument, in a
work which appeared long before the Critique of
Pure Reason;2 and urged it with much force
against those modern metaphysicians, who con¬
sider the senses as the sources of all our know¬
ledge. At a period somewhat earlier, many
very interesting quotations of a similar import
had been produced by the learned Mr Harris,
from the later commentators of the Alexandrian
school on the philosophy of Aristotle; and had
been advantageously contrasted by him with the
account given of the origin of our ideas, not
only by Hobbes and Gassendi, hut by many of
the professed followers of Locke. If this part
of the Kantian system, therefore, was new in
Germany, it certainly could have no claim to
the praise of originality, in the estimation of
those at all acquainted with English literature.3
In order, however, to strike at the root of
what the Germans call the philosophy of sensa-
morale de Price pre'sente en effet une analogic frappante avec ceile de Kantand in another part of his work, he expresses
himself thus on the same subject: “ Le plus remarquable de tous les moralistes modernes de PAngleterre est, sans con-
tredit, Richard Price On remarque 1’analogie la plus frappante entre ses idees sur les bases de lamoralite, et celles que la
philosophie critique a fait naitre en Allemagne, quoique il ne soit cependant pas possible d’elever le plus petit doute sur
I’entiere originalite de ces dernieres.”—(Tom. V. p. 303.) Is there any thing of importance in the system of Price, which
is not borrowed from the Treatise of Immutable Morality ?■ The distinguishing merit of this learned and most respectable
writer is the good sense with which he has applied the doctrines of Cudworth to the sceptical theories of his own times.
In the sequel of Ruble’s reflections on Cudworth’s philosophy, we are told, that, according to him, “the will of God is
only a simple blind power, acting mechanically or accidentally.” (“ Chez Cudworth la volonte meme en Dieu, n’est qu’un
simple pouvoir aveugle, agissant me'chaniquement ou accidentellement.”) If this were true, Cudworth ought to be ranked
among the disciples, not of Plato, but of Spinoza.
1 In this instance, a striking resemblance is observable between the language of Cudworth and that of Kant; both of
them having followed the distinctions of the Socratic school, as explained in the Thecetetus of Plato. They who are at all
acquainted with Kant’s Critique, will immediately recognise his phraseology in the passage quoted above.
2 See a review of the Prmcipal Questions and Difficulties relating to Morals, by Richard Price, I). D. London, 1758.
3 I have mentioned here only those works of a modern date, which may be reasonably presumed to be still in general
circulation among the learned. But many very valuable illustrations of the Platonic distinction between the senses and the
understanding may be collected from the English writers of the seventeenth century. Among these it is sufficient to men¬
tion at present the names of John Smith and Henry More of Cambridge, and of Joseph Glanvile, the author of Scepsis
Scientifica.
Cudworth’s Treatise of Eternal and Immutable Morality, although it appears, from intrinsic evidence, to have been com¬
posed during the lifetime of Hobbes, was not published till 1731, when the author’s manuscript came into the hands of
his grandson, Francis Cudworth Masham, one of the Masters in Chancery. This work, therefore, could not have been
known to Leibnitz, who died seventeen years before ; a circumstance which may help to account for its having attracted
so much less attention in Germany than his Intellectual System, which is repeatedly mentioned by Leibnitz in terms of the
highest praise.
From an article in the Edinburgh Review (Vol. XXVII. p. 191), we learn, that large unpublished manuscripts of Dr
Cudworth are deposited in the British Museum. It is much to be regretted (as the author of the article observes), that
they should have been so long withheld from the public. “ The press of the two Universities (he adds) would be properly
employed in works, which a commercial publisher could not prudently undertake.” May we not indulge a hope, that this
suggestion will, sooner or later, have its due effect ?
in the preface of Mosheim to his Latin version of the Intellectual System, there is a catalogue of Cudworth’s unpublished
remains, communicated to Mosheim by Dr Chandler, then Bishop of Durham. Among these are two distinct works on
the Controversy concerning Liberty and Necessity, of each of which works Mosheim has given us the general contents.
One of the chapters is entitled, “ Answer to the Objection against Liberty, [x'/'b'o avuinov." It is not probable that it con¬
tains any thing very new or important; but it would certainly be worth while to know the reply made by Cudworth to an
objection which both Leibnitz and La Place have fixed upon as decisive of the point in dispute.
DISSERTATION FIRST.
193
lion, it was necessary to trace, with some degree
of systematica] detail, the origin of our most
important simple notions ; and for this purpose
it seemed reasonable to begin with an analytical
view of those faculties and powers, to the exer¬
cise of which the development of these notions
is necessarily subsequent. It is thus that the
simple notions of time and motion presuppose
the exercise of the faculty of memory; and that
the simple notions of truth, of belief, of doiibt,
and many others of the same kind, necessarily
presuppose the exercise of the power of reason¬
ing. I do not know, that, in this anatomy of
the mind, much progress has hitherto been made
by the German metaphysicians. A great deal
certainly has been accomplished by the late Dr
Reid; and something, perhaps, has been added
to his labours by those of his successors.
According to Kant himself, his metaphysical
doctrines first occurred to him while employed
in the examination of Mr Hume’s Theory of
Causation. The train of thought by which he
was led to them will he best stated in his own
words ; for it is in this way alone that I can
hope to escape the charge of misrepresentation
from his followers. Some of his details would
perhaps have been more intelligible to my read¬
ers, had my plan allowed me to prefix to them
a slight outline of Hume’s philosophy. But this
the general arrangement of my discourse ren¬
dered impossible; nor can any material incon¬
venience result, in this instance, from the order
which I have adopted, inasmuch as Hume’s
Theory of Causation, how new soever it may
have appeared to Kant, is fundamentally the
same with that of Malebranche, and of a variety
of other old writers, both French and English.
1 “ Since the Essays (says Kant) of Locke
and of Leibnitz, or rather since the origin of
metaphysics, as far as their history extends, no
circumstance has occurred, which might have
been more decisive of the fate of this science
than the attack made upon it by David Hume.1 2 3
He proceeded upon a single but important idea
in metaphysics, the connection of cause and
effect, and the concomitant notions of power
and action. He challenged reason to answer
him what title she had to imagine, that any
thing may be so constituted as that, if it be given,
something else is also thereby inferred; for the
idea of cause denotes this. He proved beyond
contradiction, that it is impossible for reason to
think of such a connection a priori, for it con¬
tains necessity ; but it is not possible to perceive
how, because something is, something else must
necessarily be; nor how the idea of such a con¬
nection can be introduced a priori.
“ Hence, he concluded, that reason entirely
deceives herself with this idea, and that she er¬
roneously considers it as her own child, when
it is only the spurious offspring of imagination,
impregnated by experience; a subjective neces¬
sity, arising from habit and the association of
ideas, being thus substituted for an objective one
derived from perception....However hasty and
unwarrantable Hume’s conclusion might appear,
yet it was founded upon investigation; and this
investigation well deserved, that some of the
philosophers of his time should have united to
solve, more happily if possible, the problem in
the sense in which he delivered it: A complete
reform of the science might have resulted from
this solution. But it is a mortifying reflection,
that his opponents, Reid, Beattie, Oswald, and,
lastly, Priestley himself, totally misunderstood
the tendency of his problem.3 The question was
not, whether the idea of cause be in itself proper
and indispensable to the illustration of all natu-
1 See the Preface of Kant to one of his Treatises, entitled Prolegomena ad Metaphysicam quamque futuram quce qua Scientia
poterit prodire. I have availed myself in the text of the English version of Dr Willich, from the German original, which
I have carefully compared with the Latin version of Born. A few sentences, omitted by Willich, I have thought it worth
while to quote, at the foot of the page, from the Latin translation—(Elem. of Critical Philosophy, by A. F. M. Wiljlich, M. D.
p. 10. et seq. London, 1798.)
2 “ Humius—Qui quidem nullam huic cognitionis parti lucem adfudit, sed tamen excitavit scintillam, de qua sane lumen
potuisset accendi, si ea incidisset in fomitem, facile accipientem, cujusque scintillatio diligenter alta fuerit et aucta.”
s “ Non potest sine certo qwodam molestiae sensu percipi, quantopere ejus adversarii, Reidius, Oswaldus, Bcattius, et tan¬
dem Priestleius, a scopo qusestionis aberrarent, et propterea quod ea semper acciperent pro concessis, quae ipse in dubium
yocaret, contra vero cum vehementia, et maximam partem cum ingenti immodestia ea probare gestirent, quae illi nunquam
in mentem venisset dubitare, nutum ejus ad emendationem ita negligerent, ut omnia in statu pristine maneret, quasi nihil
quidquam factum videretur.”
DISS. I. PART II. 2 B
194
PRELIMINARY DISSERTATIONS.
ral knowledge, for this Hume had never doubt¬
ed ; but whether this idea be an object of thought
through reasoning a priori; and whether, in
this manner, it possesses internal evidence, in¬
dependently of all experience; consequently,
whether its utility be not limited to objects of
sense alone. It was upon this point that Hume
expected an explanation.1
“ I freely own it was these suggestions of
Hume’s which first, many years ago, roused me
from my dogmatical slumber, and gave to my
inquiries quite a different direction in the field
of speculative philosophy. I was far from being
carried away by his conclusions, the fallacy of
which chiefly arose from his not forming to him¬
self an idea of the whole of his problem, but mere¬
ly investigating a part of it, the solution of
which was impossible without a comprehensive
view of the whole. When we proceed on a well
founded, though not thoroughly digested thought,
we may expect, by patient and continued re¬
flection, to prosecute it farther than the acute
genius had done to whom we are indebted for
the first spark of this light. I first inquired,
therefore, whether Hume’s objection might not
be a general one, and soon found, that the idea
of cause and effect is far from being the only
one by which the understanding a priori thinks
of the connection of things; but rather that the
science of metaphysics is altogether founded
upon these connections. I endeavoured to as¬
certain their number; and, having succeeded in
this attempt, I proceeded to the examination of
those general ideas, which, I was now convin¬
ced, are not, as Hume apprehended, derived
from experience, but arise out of the pure under¬
standing. This deduction, which seemed im¬
possible to my acute predecessor, and which
nobody besides him had ever conceived, al¬
though every one makes use of these ideas,
without asking himself upon what their objec¬
tive validity is founded; this deduction, I say,
was the most difficult which could have been
undertaken for the behoof of metaphysics ; and
what was still more embarrassing, metaphysics
could not here offer me the smallest assistance,
because that deduction ought first to establish
the possibility of a system of metaphysics. As
I had now succeeded in the explanation of
Hume’s problem, not merely in a particular in¬
stance, but with a view of the whole power of
pure reason, I could advance with sure though
tedious steps, to determine completely, and
upon general principles, the compass of Pure
Reason, both what is the sphere of its exertion,
and what are its limits ; which was all that was
required for erecting a system of metaphysics
upon a proper and solid foundation.”
It is difficult to discover any thing in the fore¬
going passage on which Kant could found a
claim to the slightest originality. A variety of
English writers had, long before this work ap¬
peared, replied to Mr Hume, by observing that
the understanding is itself a source of new ideas,
and that it is from this source that our notions
of cause and effect are derived. “ Our cer¬
tainty (says Dr Price) that every new event re¬
quires some cause, depends no more on experi¬
ence than our certainty of any other the most
obvious subject of intuition. In the idea of every
change, is included that of its being an effect.”*
In the works of Dr Reid, many remarks of the
same nature are to be found; but, instead of
quoting any of these, I shall produce a passage
from a much older author, whose mode of think¬
ing and writing may perhaps be more agreeble
to the taste of Kant’s countrymen than the sim¬
plicity and precision aimed at by the disciples
of Locke.
“ That there are some ideas of the mind (says
Dr Cudworth), which were not stamped or im¬
printed upon it from the sensible objects with¬
out, and therefore must needs arise from the in¬
nate vigour and activity of the mind itself, is
evident, in that there are, First, Ideas of such
things as are neither affections of bodies, nor
could be imprinted or conveyed by any local
motions, nor can be pictured at all by the fancy
! Although nothing can be more unjust than these remarks, in the unqualified form in which they are stated by Kant,
it, must, I think, be acknowledged, that some grounds for them have been furnished by occasional passages which dropped
from the pens of most of Mr Hume’s Scottish opponents.
2 Review of the Principal Questions and Difficulties in Morals, Chap. i. sect. 2. The first edition of this book was printed
in 1758.
DISSERTATION FIRST.
195
in any sensible colours; such as are the ideas of
wisdom, folly, prudence, imprudence, know¬
ledge, ignorance, verity, falsity, virtue, vice,
honesty, dishonesty, justice, injustice, volition,
cogitation, nay of sense itself, which is a species
of cogitation, and which is not perceptible by
any sense ; and many other such like notions as
include something of cogitation in them, or refer
to cogitative beings only ; which ideas must
needs spring from the active power and innate
fecundity of the mind itself,1 2 3 because the cor¬
poreal objects of sense can imprint no such
things upon it. Secondly, In that there are
many relative notions and ideas, attributed as
well to corporeal as incorporeal things, that pro¬
ceed wholly from the activity of the mind com¬
paring one thing with another. Such as are
Cause, Effect, means, end, order, proportion,
similitude, dissimilitude, equality, inequality,
aptitude, inaptitude, symmetry, asymmetry,
whole and part, genus and species, and the like.”
Immutable Morality, pp. 148, 149.
It is not my business at present to inquire
into the solidity of the doctrine here maintained.
I would only wish to be informed what additions
have been made by Kant to the reply given to
Mr Hume by our English philosophers, and to
direct the attention of my readers to the close
resemblance between this part of Kant’s system,
and the argument which Cud worth opposed to
Hobbes and Gassendi considerably more than a
century ago.*
The following passage, from the writer last
quoted, approaches so nearly to what Kant and
other Germans have so often repeated of the dis¬
tinction between subjective and objective truth,
that I am tempted to connect it with the fore¬
going extract, as an additional proof that there
are, at least, some metaphysical points, on which
we need not search for instruction beyond our
own island.
“ If there were no other perceptive power, or
faculty, distinct from external sense, all our
perceptions would be merely relative, seeming,
and fantastical, and not reach to the absolute
and certain truth of any thing; and every one
would but, as Protagoras expounds, ‘ think his
own private and relative thoughts truths,’ and
all our cogitations being nothing but appearan¬
ces, would be indifferently alike true phantasms,
and one as another.
“ But we have since also demonstrated, that
there is another perceptive power in the soul
superior to outward sense, and of a distinct na¬
ture from it, which is the power of knowing or
understanding, that is, an active exertion from
the mind itself. And, therefore, has this grand
eminence above sense, that it is no idiopathy, not
a mere private, relative, seeming, and fantasti¬
cal thing, but the comprehension of that which
absolutely is and is not.”5
After enlarging on the distinction between
the sensitive faculty and the understanding,
Kant proceeds to investigate certain essential
conditions, without which neither the sensitive
faculty nor its objects are conceivable. These
conditiens are time and space, which, in the lan¬
guage of Kant, are the forms of all phenomena.
What his peculiar ideas are concerning their
nature and attributes, my readers will find stat¬
ed in his own words at the end of this Discourse,
in an extract from one of his Latin publica¬
tions.4 From that extract, I cannot promise
them much instruction; but it will at least en¬
able them to judge for themselves of the pecu¬
liar character of Kant’s metaphysical phraseo¬
logy. In the mean time, it will be sufficient to
mention here, for the sake of connection, that
he denies the objective reality both of time and
of space. The former he considers merely as a
subjective condition, inseparably connected with
the frame of the human mind, in consequence
of which, it arranges sensible phenomena ac¬
cording to a certain law, in the order of succes¬
sion. As to the latter, he asserts, that it is
nothing objective or real, inasmuch as it is neither
1 This is precisely the language of the German school: “ Les veritds necessaires, “ says Leibnitz, “ sont le produit im-
mediat de Tactivite interieure.”—(Tome I. p. 686. Tome II. pp. 42, 325. See Degerando, Hist. Comp. Tome II. p. 96.)
2 In the attempt, indeed, which Kant has made to enumerate all the general ideas which are not derived from expe¬
rience, but arise out of the pure understanding, he may well lay claim to the praise of originality. On this object I shall
only refer my readers to Note X X at the end of this Dissertation.
3 Immutable Morality, p. 264, et seq.
4 See Note Y Y.
196
PRELIMINARY DISSERTATIONS.
a substance, nor an accident, nor a relation;
that its existence, therefore, is only subjective
and ideal, depending on a fixed law, inseparable
from the frame of the human mind. In conse¬
quence of this law, we are led to conceive all
external things as placed in space; or, as Kant
expresses it, we are led to consider space as the
fundamental form of every external sensation.
In selecting Kant’s speculations concerning
time and space, as a specimen of his mode of
writing, I was partly influenced by the consi¬
deration, that it furnishes, at the same time, a
remarkable example of the concatenation which
exists between the most remote and seemingly
the most unconnected parts of his system. Who
could suppose that his opinions on these sub¬
jects, the most abstract and the most contro¬
verted of any in the whole compass of metaphy¬
sics, bore on the great practical question of the
freedom of the Human Will ? The combina¬
tion appears, at first sight, so very extraordi¬
nary, that I have no doubt I shall gratify the
curiosity of some of my readers by mentioning a
few of the intermediate steps which, in this argu¬
ment, lead from the premises to the conclusion.
That Kant conceived the free agency of man
to he necessarily implied in his moral nature
(or, at least, that he was anxious to offer no
violence to the common language of the world
on this point), appears from his own explicit de¬
clarations in various parts of his works. “ Vo¬
luntas libera (says he in one instance) eadem
est cum voluntate legibus moralibus obnoxia.”1
In all the accounts of Kant’s philosophy,
which have yet appeared from the pens of his
admirers in this country, particular stress is
laid on the ingenuity with which he has unloos¬
ed this knot, which had baffled the wisdom of
all his predecessors. The following are the
words of one of his own pupils, to whom we are
indebted for the first, and, I think, not the least
intelligible, view of his principles, which has
been published in our language.2 3
“ Professor Kant is decidedly of opinion, that
although many strong and ingenious arguments
have been brought forward in favour of the
freedom of the will, they are yet very far from
being decisive. Nor have they refuted the ar¬
guments urged by the Necessitarians, hut by an
appeal to mere feeling, which, on such a ques¬
tion, is of no avail. For this purpose, it is in¬
dispensably necessary to call to our assistance
the principles of Kant.”
“ In treating this subject (continues the same
author), Kant begins with showing that the
notion of a Free Will is not contradictory. In
proof of this he observes, that, although every
human action, as an event in time, must have a
cause, and so on ad infinitum; yet it is certain,
that the laws of cause and effect can have a
place there only where time is, for the effect
must he consequent on the cause. But neither
time nor space are properties of things; they
are only the general forms under which man is
allowed to view himself and the world. It fol¬
lows, therefore, that man is not in time nor in
space, although the forms of his intuitive ideas
are time and space. But if man exist not in
time and space, he is not influenced by the laws
of time and space, among which those of cause
and effect hold a distinguished rank ; it is, there¬
fore, no contradiction to conceive, that, in such
an order of things, man may he free.”5
In this manner Kant establishes the possibili¬
ty of man’s freedom ; and, farther than this, he
does not conceive himself warranted to proceed
on the principles of the critical philosophy. The
first impression, certainly, which his argument
1 See Born’s Latin Translation of Kant’s Works, relating to the Critical Philosophy, Vol. II. p. 325, et seq. See also the
Preface to Vol. III.
2 A General and Introductory View of Professor Kant's Principles concerning Man, the World, and the Deity, submitted to the
consideration of the Learned, by F. A. Nitsch, late Lecturer on the Latin Language and Mathematics in the Royal Frederi-
cianum College at Kdnigsberg, and pupil of Professor Kant. London, 1796. Pp. 172, 173.
This small performance is spoken of in terms highly favourable, by the other writers who have attempted to introduce
Kant’s philosophy into England. It is called by Dr Willich an excellent publication (Elements of the Critical Philosophy,
p. 62.); and is pronounced by the author of the elaborate articles on that subject in the Encyclopaedia Londonemis to be a ster¬
ling work. “ Though at present very little known, I may venture,” says this writer, “ to predict, that, as time rolls on,
and prejudices moulder away, this work, like the Elements of Euclid, will stand forth as a lasting monument of pure truth.”
—See Note Z Z.
3 Nitsch, &c. pp. 17b 1/5-
DISSERTATION FIRST.
197
produces on the mind is, that his own opinion
was favourable to the scheme of necessity. For
if the reasonings of the Necessitarians he ad¬
mitted to he satisfactory, and if nothing can he
opposed to them hut the incomprehensible pro¬
position, that man neither exists in space nor in
time, the natural inference is, that this propo¬
sition was brought forward rather to save ap¬
pearances, than as a serious objection to the uni¬
versality of the conclusion.
Here, however, Kant calls to his aid the prin¬
ciples of what he calls 'practical reason. Deeply
impressed with a conviction that morality is the
chief concern of man, and that morality and the
freedom of the human will must stand or fall to¬
gether, he exerts his ingenuity to show, that the
metaphysical proof already brought of the pos¬
sibility of free agency, joined to our own con¬
sciousness of a liberty of choice, affords evidence
of the fact fully sufficient for the practical regu¬
lation of our conduct, although not amounting
to what is represented as demonstration in the
Critique of Pure Reason.1
It is impossible to combine together these two
parts of the Kantian system, without being
struck with the resemblance they hear to the
deceitful sense of liberty to which Lord Kames
had recourse (in the first edition of his Essays
on Morality and Natural Religion), in order to
reconcile our consciousness of free agency with
the conclusions of the Necessitarians. In both
cases, the reader is left in a state of most un¬
comfortable scepticism, not confined to this par¬
ticular question, but extending to every other
subject which can give employment to the hu¬
man faculties.2
In some respects, the functions ascribed by
Kant to his practical reason are analogous to
those ascribed to common sense in the writings
of Beattie and Oswald. But his view of the
subject is, on the whole, infinitely more excep¬
tionable than theirs, inasmuch as it sanctions
the supposition, that the conclusions of pure
reason are, in certain instances, at variance with
that modification of reason which was meant by
our Maker to be our guide in life ; whereas the
constant language of the other writers is, that
all the different parts of our intellectual frame
are in the most perfect harmony with each other.
The motto which Beattie has prefixed to his
book,
“ Nunquam aliud natura, aliud sapientia dicit,’
expresses, in a few significant words, the whole
substance of his philosophy.
1 The account of this part of Kant’s doctrine given by M. Buhle agrees in substance with that of Mr Nitsch : “ Toute
moralite des actions repose uniquement sur la disposition practique, en tant qu’elle est determinee par la loi morale seule.
Si 1’on considere cette disposition comme phenomena dans la conscience; e’est un evenement naturel, elle obeit a la loi de la
causalite', elle repose sur ce que I’homme a eprouve auparavant dans le terns, et elle fait partie du caractere empirique de
I’homme. Mais on peut aussi la considerer comme un acte de la liberte raisonnable: Alors elle n’est plus soumise a la loi
de la causalite ; elle est inde'pendante de la condition du temps, elle se rapporte a une cause intelligible, la liberte', et elle
fait partie du caractere intelligible de I’homme. On ne peut, a la verite, point acquerir la moindre connoissance des objets
intelligibles; mais la liberte n’est pas moins un fait de la conscience. Done les actions exterieures sont indifferentes pour
la moralite de I’homme. La bonte morale de I’liomme consiste uniquement dans sa volonte moralement bonne, et celle-ci
consiste en ce que la volonte soit determine'e par la loi morale seule.”—(Hist, de la Philosophic Moderne, par J. G. Buble,
Tom. YI. pp. 504, 505.)
Very nearly to the same purpose is the following statement by the ingenious author of the article Leibnitz in the Bio-
graphic Universelle:—“ Comment accorder le fatum et la liberte, I’imputation morale et la dependence des etres finies
Kant croit echapper a cet e'cueil en ne soumettant a la loi de causalite (au determinisme de Leibnitz) que le monde pheno-
menique, et en affranchissant de ce princijfe 1’ame comme noumcne ou chose en soi, envisageant ainsi chaqiie action comme
appartenant a un double serie a la fois; a 1’ordre physique ou elle est enchainde a ce qui precede et a ce qui suit par les
liens communs de la nature, et d Pordre morale, ou une determination produit un effet, sans que pour expliquer cette voli¬
tion et son resultat, on soit renvoye a un dtat antecedent.”
The author of the above passage is M. Staffer, to whom we are indebted for the article Kant in the same work. For
Kant’s own view of the subject consult his Critique of Pure Reason, passim, particularly p. 99. et seq. of Born’s Translation,
Vol. III.
2 The idea of Kant (according to his own explicit avowal) was, that every being, which conceives itself to be free, whe¬
ther it be in reality so or not, is rendered by its own belief a moral and accountable agent. “ Jam equidem dico: quteque
natura, quae non potest nisi sub idea libertatis agere, propter id ipsum, respectu practice, reipsa libera est; hoc est, ad earn
valent cunctae leges, cum libertate arctissime conjunctae perinde, ac voluntas ejus etiam per se ipsam, et in philosophia
theoretica probata, libera declaretur—(Kantii Opera, Vol. II. p. 926.)
This is also the creed professed by the Abbe Galiani, a much more dangerous moralist than Kant, because he is aivyays
intelligible, and often extremely lively and amusing. “ L’homme est done libre, puisqu’il est intimement persuade de
1’etre, et que cela vaut tout autant que la liberte. Voila done le mechanisme de Vunivers explique clair comme de Veau de roche."
The same author farther remarks, “ La persuasion de la liberte constitue 1’essence de I’homme. On pourroit meme dtTi-
nir I’homme un animal qui se croit libre, et ce seroit une definition complete.”—f Corrcspondance de VAbbe. Galiani, Tome l.
pp. 339, 340. A Paris, 1818.)
198
PRELIMINARY DISSERTATIONS.
It is to tlie same practical modification of
reason that Kant appeals in favour of the ex¬
istence of the Deity, and of a future state of re¬
tribution, both of which articles of belief he
thinks derive the whole of their evidence from
the moral nature of man. His system, there¬
fore, as far as I am able to comprehend it, tends
rather to represent these as useful credenda, than
as certain or even as probable truths. Indeed,
the whole of his moral superstructure will he
found to rest ultimately on no better basis than
the metaphysical conundrum^ that the human
mind (considered as a noumenon and not as a
phenomenon) neither exists in space nor in time.
That it was Kant’s original aim to establish a
system of scepticism, I am far from being dis¬
posed to think.1 The probability is, that be
began with a serious wish to refute the doctrines
of Hume; and that, in the progress of his in¬
quiries, he met with obstacles of which he was
not aware. It was to remove these obstacles
that he had recourse to practical reason ; an idea
which has every appearance of being an after¬
thought, very remote from his views when he
first undertook his work. This, too, would
seem, from the following passage (which I trans¬
late from Degerando), to have been the opinion
of one of Kant’s ablest German commentators,
M. Reinhold: “ Practical Reason (as Reinhold
ingeniously observes) is a wing which Kant has
prudently added to his edifice, from a sense of
the inadequacy of the original design to answer
the intended purpose. It bears a manifest re¬
semblance to what some philosophers call an ap¬
peal to sentiment, founding belief on the neces¬
sity of acting. Whatever contempt Kant may
affect for popular systems of philosophy, this
manner of considering the subject is not unlike
the disposition of those who, feeling their inabi¬
lity to obtain, by the exercise of their reason, a
direct conviction of their religious creed, cling
to it nevertheless with a blind eagerness, as a
support essential to their morals and their hap¬
piness.” [Hist. Comparee, Vol. II. pp. 243, 244.)
The extraordinary impression produced for a
considerable time in Germany, by the Critique
of Pure Reason, is very shrewdly, and I suspect
justly, accounted for by the writer last quoted:
“ The system of Kant was well adapted to flat¬
ter the weaknesses of the human mind. Curio¬
sity was excited, by seeing paths opened which
had never been trodden before. The love of
mystery found a secret charm in the obscui’ity
which enveloped the doctrine. The long and
troublesome period of initiation was calculated
to rouse the ambition of bold and adventurous
spirits. Their love of singularity was gratified
by the new nomenclature; while their vanity
exulted in the idea of being admitted into a privi¬
leged sect, exercising, and entitled to exercise,
the supreme censorship in philosophy. Even
men of the most ordinary parts, on finding
themselves called to so high functions, lost sight
of their real mediocrity, and conceived them¬
selves transformed into geniuses destined to
form a new era in the history of reason.
<c Another inevitable effect resulted from the
universal change operated by Kant in his terms,
in his classifications, in his methods, and in the
enunciation of his problems. The intellectual
powers of the greater part of the initiated were
too much exhausted in the course of their long
noviciate, to be qualified to judge soundly of the
doctrine itself. They felt themselves, after so
many windings, lost in a labyrinth, and were
unable to dispense with the assistance of the
guide who had conducted them so far. Others,
after so great a sacrifice, wanted the courage to
confess to the world, or to themselves, the dis¬
appointment they had met with. They attached
themselves to the doctrine in proportion to the
sacrifice they^had made, and estimated its value
by the labour it had cost them. As for more
superficial thinkers, they drew an inference from
the novelty of the form in favour of the novelty
of the matter, and from the novelty of the mat¬
ter in favour of its importance.
“ It is a great advantage for a sect to possess
1 On the contrary, he declares explicitly (and I give him full credit for the sincerity of his words), that he considered
his Critique of Pure Reason as the only effectual antidote against the opposite extremes of scepticism and of superstition, as
well as against various heretical doctrines which at present infect the schools of philosophy. “ Hac igitur sola (Philosophia
Critica) et materialismi, et fatalism!, et Atheismi, et diffid.entiae profanse, et fanatismi, et superstitionis, quorum virus ad
universos potest penetrare, tandemque etiam et idealism! et scepticismi, qui magis scholis sunt pestiferi, radices ipsse pos-
sunt praecidi.”—(Kant, Prcef. Posterior, p. 35.) I
DISSERTATION FIRST.
199
a distinguishing garb and livery. It was thus
that the Peripatetics extended their empire so
widely, and united their subjects in one common
obedience. Kant had, over and above all this,
the art of insisting, that his disciples should
belong exclusively to himself. He explicitly
announced, that he was not going to found a
school of Eclectics, but a school of his own;
a school not only independent, but in some
measure hostile to every other; that he could
admit of no compromise with any sect whatever;
that he was come to overturn everything which
existed in philosophy, and to erect a new edifice
on these immense ruins. The more decided and
arrogant the terms were in which he announced
his design, the more likely was it to succeed;
for the human mind submits more easily to an
unlimited than to a partial faith, and yields
itself up without reserve, rather than consent to
cavil about restrictions and conditions even in
favour of its own independence.”
With these causes of Kant’s success another
seems to have powerfully conspired; the indis-
soluble coherence and concatenation of all the
different parts of his philosophy. “ It is on this
concatenation (says M. Prevost) that the admi¬
ration of Kant’s followers is chiefly founded.”
Grant only (they boast) the first principles of the
Critical Philosophy, and you must grant the whole
system. The passage quoted on this occasion by
M. Prevost is so forcibly expressed, that I
cannot do it justice in an English version:
“ Ab bine enim capitibus fluere necesse est om-
nem philosophise criticse rationis pur® vim atque
virtutem; namque in ea contextus rerum pror-
sus mirabilis est, ita ut extrema primis, media
utrisque, omnia omnibus respondeant; si pi'ima
dederis danda sunt omnia.”1 No worse ac¬
count could well have been given of a philo¬
sophical Avork on such a subject; nor could any
of its characteristical features have been pointed
out more symptomatic of its ephemeral reputa¬
tion. Supposing the praise to be just, it repre¬
sented the system, however fair and imposing
in its first aspect, as vitally and mortally vulne¬
rable (if at all vulnerable) in every point; and,
accordingly, it was fast approaching to its dis¬
solution before the death of its author. In Ger¬
many, at present, we are told, that a pure Kan¬
tian is scarcely to be found.3 But there are
many Semi-Kantians and Anti-Kantians, as
well as partisans of other schemes built out of
the ruins of the Kantian philosophy.3 “ In
fine (says a late author), the Critique of Pure
Reason, announced with pomp, received with
fanaticism, disputed about with fury, after hav¬
ing accomplished the overthrow of the doctrines
taught by Leibnitz and Wolff, could no longer
support itself upon its own foundations, and has
produced no permanent result, but divisions and
enmities, and a general disgust at all systemati¬
cal creeds.”4 If this last effect has really re¬
sulted from it (of which some doubts may per¬
haps be entertained), it may be regarded as a
favourable symptom of a sounder taste in mat¬
ters of abstract science, than has ever yet pre¬
vailed in that country.5
To these details, I have only to add a re-
_1 See some very valuable strictures on Kant, in the learned and elegant sketch of the present state of philosophy, sub¬
joined to M. Prevost’s French translation of Mr Smith’s posthumous works. The Latin panegyric on the critical philoso¬
phy is quoted from a work with which I am unacquainted, Fred. Gottlob Bornn de Scientia et Conjeclura.
2 On this subject, see Degerando, Tom. II. p. 333.
a See Degerando and De Donald.
4 The words in the original are, “ LTn ddgout gdndrale de toute doctrine.” But as the same word doctrine is, in a former
part of the same sentence, applied to the systems of Leibnitz and of Wolff, I have little doubt, that, in substituting for
doctrine the phrase systematical creeds, I have faithfully rendered the meaning of my author.—(See Recherches Philosophiques.
par M. De Donald, Tom. I. pp. 43, 44.)
5 The passion of the Germans for systems is a striking feature in their literary taste, and is sufficient of itself to show,
that they have not yet passed their noviciate in philosophy. “ To all such (says Mr Maclaurin) as have just notions of
the Great Author of the Universe, and of his admirable workmanship, all complete and finished systems must appear very
suspicious.” At the time when he wrote, such systems had not wholly lost their partisans in England; and the name of
System continued to be a favourite title for a book even among writers of the highest reputation. Hence the System of
Moral Philosophy by Hutcheson, and the Complete System of Optics by Smith, titles which, when compared with the subse¬
quent progress of these two sciences, reflect some degree of ridicule upon their authors.
When this affectation of systematical method began, in consequence of the more enlarged views of philosophers, to give
way to that aphoristical style so strongly recommended and so happily exemplified by Lord Bacon, we find some writers
of the old school complaining of the innovation, in terms not unlike those in which the philosophy of the English has been
censured by some German critics. “ The best wav (says Dr Watts) to learn any science, is to begin with a regular sys-
200
PRELIMINARY DISSERTATIONS.
mark of Degeranclo’s, which I have found amply
confirmed within the circle of my own experi¬
ence. It might furnish matter for some useful
reflections, hut I shall leave my readers to draw
their own conclusions from it. 44 Another re¬
markable circumstance is, that the defence of
the Kantians turned, in general, not upon the
truth of the disputed proposition, but upon the
right interpretation of their master’s meaning,
and that their reply to all objections has con¬
stantly begun aud ended with these words, You
have not understood us.”
Among the various schools which have ema¬
nated from that of Kant, those of Fichte and
Schelling seem to have attracted among their
countrymen the greatest number of proselytes.
Of neither am I able to speak from my own
knowledge; nor can I annex any distinct idea
to the accounts which are given of their opinions
by others. Of Fichte’s speculations about the
philosophical import of the pronoun I (Qu’est-
ce que le moi ? as Degerando translates the ques¬
tion), I cannot make any thing. In some of
his remarks, he approaches to the language of
those Cartesians who, in the progress of their
doubts, ended in absolute egoism: but the ego1
of Fichte has a creative power. It creates ex¬
istence, and it creates science ; two tilings (by the
way) which, according to him, are one and the
same. Even my own existence, he tells me,
commences only with the reflex act, by which
I think of the pure and primitive ego. On this
identity of the intelligent ego and the existing
ego (which Fichte expresses by the formula ego
= ego) all science ultimately rests.—But on this
part of his metaphysics it would be idle to en¬
large, as the author acknowledges, that it is not
to be understood without the aid of a certain
transcendental sense, the want of which is wholly
irreparable; a singular admission enough (as
Degerando observes), on the part of those criti¬
cal philosophers who have treated with so much
contempt the appeal to Common Sense in the
writings of some of their predecessors.®
44 In the history of beings there are (according
to Fichte) three grand epochs; the first belongs
to the empire of chance ; the second is the reign
of nature; the third will he the epoch of the
existence of God. For God does not exist yet;
he only manifests himself as preparing to exist.
Nature tends to an apotheosis, and may be re¬
garded as a sort of divinity in the germ.”3
The account given by Madame de Stael of
this part of Fichte’s system is considerably dif¬
ferent : 44 He was heard to say, upon one oc¬
casion, that in his next lecture he 4 was going to
create God,’—an expression which, not without
reason, gave general offence. His meaning was,
that he intended to show how the idea of God
arose and unfolded itself in the mind of man.”4
How far this apology is well-founded, I am not
competent to judge.
The system of Schelling is, in the opinion of
Degerando, but an extension of that of Fichte;
connecting with it a sort of Spinozism grafted
on Idealism. In considering the primitive ego
tem. N ow (ne continues), we deal mucli m essays, and unreasonably despise systematical learning; whereas our fathers
had a just value for regularity and systems.” Had Dr Watts lived a few years later, I doubt not that his good sense
would have led him to retract these hasty and inconsiderate decisions.
1 In order to avoid the intolerable aukwardness of such a phrase as the /, I have substituted on this occasion the Latin
pronoun for the English one.
2 Hist. Comparee, &c. Tome II. pp. 300, 301. See also the article Fichte in this Encyclopaedia.
3 Hist. Comparee, See. Tome II. p. 314. The doctrine here ascribed to Fichte by Degerando, although its unparalleled
absurdity might well excite some doubts about the correctness of the historian, is not altogether a novelty in the history
of philosophy. It is in point of fact nothing more than a return to those gross conceptions of the mind in the infancy of
human reason, which Mr Smith has so well described in the following passage:—“ In the first ages of the world, the seem¬
ing incoherence of the appearances of nature so confounded mankind, that they despaired of discovering in her operations
any regular system Their gods, though they were apprehended to interpose upon some particular occasions, were
so far from being regarded as the creators of the world, that their origin was apprehended to be posterior to that of the
world. The earth (according to Hesiod) was the first production of the chaos. The heavens arose out of the earth, and
from both together, all the gods who afterwards inhabited them. Nor was this notion confined to the vulgar, and to those
poets who seem to have recorded the vulgar theology The same notion of the spontaneous origin of the world was
embraced (as Aristotle tells us) by the early Pythagoreans. . . Mind, and understanding, and consequently Deity, being the
most perfect, were necessarily, according to them, the last productions of nature. For, in all other things, what was most
perfect, they observed, always came last: As in plants and animals, it is not the seed that is most perfect, but the complete
animal, with all its members in the one ; and the complete plant, with all its branches, leaves, flowers, and fruits, in the
other.” (Smith’s Post. Essays on Philosophical Subjects, pp. 106, 1070
4 j)e VAllemagne. Tome III. p. 107- Londres, 1813.
DISSERTATION FIRS1.
201
as the source of all reality as well as of all science,
and in thus transporting the mind into an in¬
tellectual region, inaccessible to men possessed
only of the ordinary number of senses, both
agree ; and to this vein of transcendental mysti¬
cism may probably be ascribed the extraordinary
enthusiasm with which their doctrines appear to
have been received by the German youth. Since
the time when Degerando wrote, a new and
very unexpected revolution is said to have taken
place among Schelling’s disciples; many of them,
originally educated in the Protestant faith, hav¬
ing thrown themselves into the bosom of the
Catholic church1 2 “ The union of the faith¬
ful of this school forms an invisible church,
which has adopted for its symbol and watch¬
word, the Virgin Mary; and hence rosaries are
sometimes to be seen in the hands of those who
reckon Spinoza among the greatest prophets.”
It is added, however, with respect to this invi¬
sible church, that <c its members have embraced
the Catholic religion, not as the true religion,
but as the most poeticala thing not impro¬
bable among a people who have so strong a dis¬
position to mingle together poetry and meta¬
physics in the same compositions.3 But it is
painful to contemplate these sad aberrations of
human reason; nor would I have dwelt on them
so long as I have done, had I not been anxious
to convey to my readers a general, but I trust
not unfaithful, idea of the style and spirit of a
philosophy, which, within the short period of
our recollection, rose, flourished, and fell; and
which, in every stage of its history, furnished
employment to the talents of some of the most
learned and able of our contemporaries.3
The space which I have allotted to Kant has
so far exceeded what I intended he should oc¬
cupy, that I must pass over the names of many
of his countrymen much more worthy of public
attention. In the account given by Degerando
of the opponents of the Kantian system, some
remarks are quoted from different writers, which
convey a very favourable idea of the works from
which they are borrowed. Among these I would
more particularly distinguish those ascribed to
Jacobi and to Reinhold. In the Memoirs, too,
of the Berlin Academy, where, as Degerando
justly observes, the philosophy of Locke found
an asylum, while banished from the rest ot
Germany, there is a considerable number of
metaphysical articles of the highest merit.4
Nor must I omit to mention the contributions
to this science by the university of Goettingen ;
more especially on questions connected with the
philosophy of language. I have great pleasure,
also, in acknowledging the entertainment I have
received, and the lights I have borrowed from
the learned labours of Meiners and of Herder ;
but none of these are so closely connected with
the history of metaphysics as to justify me in
entering into particular details with respect to
them. I am ashamed to say that, in Great Bri¬
tain, the only one of these names which has
been much talked of is that of Kant; a circum¬
stance which, I trust, will apologise for the
length to which the foregoing observations have
extended.5
1 See a paper by M. G. Schweighauser in the London Monthly Magazine for 1804, p. 207-
2 “ Aussi les Allemands melent ils trop souvent la Metaphysique a la Poesie.”—Allemagne, Vol. III. p. 133. “ No¬
thing (says Mr Hume) is more dangerous to reason than the flights of imagination, and nothing has been the occasion of
more mistakes among philosophers. Men of bright fancies may, in this respect, be compared to those angels, whom the
scripture represents as covering their eyes with their wings.”—( Treatise of Human Nature, Vol. I. p. 464.) .
3 According to a French writer, who appears to have resided many years in Germany, and who has enlivened a short
Essay on the Elements of Philosophy with many curious historical details concerning Kant and his successors, both 1. ichte
and Schelling owed much of their reputation to the uncommon eloquence displayed in their academical lectures:—“ Cette
doctrine sortait de la bouche de Fichte, revetu de ces ornemens qui donnent la jeunesse, la beaute, et la force au discours.
On ne se lassait point en re'coutant.”
Of Schelling he expresses himself thus:—“ Schelling, appele a I’universite de Wirzbourg, y attira par sa reputation un
concours nombreux d’auditeurs, qu’il enchainait a ses lemons par la richesse de sa diction et par 1’etendue de ses connois-
sances. De Ik, il est venu k Munich, oiije le revis en 1813. On dit qu’il a embrasse la religion Catholique.”—(Essai sur
les Elemens de la Philosophic, par G. Gley, Principal au College d’Alenqon. Paris, 1817- pp. 152, 138.)
4 In a volume of this collection (for the year 1797)? which happens to be now lying before me, there are three protoun
and important Memoirs on Probabilities, by M. Prevost and M. 1’Huillier. Neither of these authors, I am aware, is or Ger¬
man origin, but as the Academy of Berlin has had the merit to bring their papers before the public, I could not omi ns
opportunity of recommending them to the attention of my readers. To a very important observation made by u • re*
vost and I’Huillier, which has been the suoject of some dispute, I am happy to avail myself of the same opportum y o ex¬
press my unqualified assent.—(See pp. 15. and 31. of the memoirs belonging to the Classe de Philosophic Speculative. J
* See Note AAA.
DISS. I. PART II. ^ C
202
PRELIMINARY DISSERTATIONS.
The only other country of Europe from which
any contributions to metaphysical philosophy
could be reasonably looked for, during the eigh¬
teenth century, is Italy; and to this particular
branch of science I do not know that any Italian
of much celebrity has, in these later times, turn¬
ed his attention. The metaphysical works of
Cardinal Gerdil (a native of Savoy) are extolled
by some French writers; but none of them have
ever happened to fall in my way.1 At a more
recent period, Genovesi, a Neapolitan philoso¬
pher* (best known as apolitical economist), has
attracted a good deal of notice by some meta¬
physical publications. Their chief object is said
to be to reconcile, as far as possible, the opinions
of Leibnitz with those of Locke. “ Pendant
que Condillac donnait inutilement des le9ons a
un Prince d’ltalie, Genovesi en donnait avec
plus de succes a ses eleves Napolitains: il com-
binait le mieux qu’il lui etoit possible les theories
de Leibnitz, pour lequel il eut toujours une pre¬
vention favorable, avec celle de Locke, qu’il
accredita le premier en Italic.”3 Various other
works of greater or less celebrity, from Italian
authors, seem to announce a growing taste in that
part ot Europe for these abstract researches. The
names of Francisco Soave, of Biagioli, and of
Mariano Gigli, are advantageously mentioned by
their countrymen; but none of their works, as
far as I can learn, have yet reached Scotland.
Indeed, with the single exception of Boscovich,
I recollect no writer on the other side of the
Alps, whose metaphysical speculations have been
heard of in this island. This is the more to be
regretted, as the specimens he has given, both
of originality and soundness in some of his ab¬
stract discussions, convey a very favourable idea
of the schools in which he received his education.
The authority to which he seems most inclined
to lean is that of Leibnitz; but, on all important
questions he exercises his own judgment, and
often combats Leibnitz with equal freedom and
success. Remarkable instances of this occur in
his strictures on the principle of the sufficient rea¬
son, and in the limitations with which he has ad¬
mitted the law of continuity.
The vigour, and, at the same time, the ver¬
satility of talents, displayed in the voluminous
works of this extraordinary man, reflect the
highest honour on the country which gave him
birth, and would almost tempt one to give credit
to the theory which ascribes to the genial cli¬
mates of the south a beneficial influence on the
intellectual frame. Italy is certainly the only
His two first; piiblienlions, which were directed against the philosophy of Locke (if we may judge from their titles)
are not likely, in the present times, to excite any curiosity. 1. The Immateriality of the Soul Demonstrated against Mr Locke
on the same Principles on which this Philosopher has Demonstrated the Existence and the Immateriality of God. Turin, I747!
2. Defence of the Opinion of Malehranche, on the Nature and Origin of our Ideas, against the examination of Mr Locke. Turin
yf5- The only other works of Gerdil which I have seen referred to are, A Dissertation on the Incompatibility of the Prin-
clPjf °f Pescartes with those of Spinoza ; and A Refutation of some Principles maintained in the Emile of Rousseau.
Of this last performance, Rousseau is reported to have said, “ Voila I unique icrit public contre moi que i'ai trouve diene
A tire lu en entier.,' (Nouveau Diet. Hist, article Gerdil.) In the same article, a reference is made to a public discourse of
the celebrated M. Mairan, of the Academy of Sciences, in which he pronounces the following judgment on Gerdil’s meta-
p lysical powers : Gerdilporte avec lui dans tous ces discours un esprit geometrique, qui manque trap souvent aux geometres
3 Born 1712, died 1769.
i E\\cycl°pzdique, ou Analyse Raisonnee des Productions les plus Remarquables dans la Litterature, les Sciences, et les Arts.
, ° ' '1’‘ue !iVra!SOn.’ P- ®.15: p.aris’ Mars 1819- (The writer of the article quoted in the text is M. Sarpi, an Italian bv
birth, who, alter having distinguished himself by various publications in his own country, has now (if I am not mistaken)
nxea ms residence at Pans. In his own philosophical opinions, he seems to be a follower of Condillac’s school, otherwise
SCa,rCe j hav<i sPoken so highly as he has done of the French Ideologists: “ L’Ideologie qui, d’apres sa denomi-
n-I r,^cen’teiip0unait e^e C,onsi(„ler,t“e comme specialement due aux Franqais, mais qui est aussi ancienne que la philoso-
Teiarp0ur 0bjet la gyration des iddes et I’analyse des facultes qui concourent a leur formation, n’est pas
etrangere aux Itahens, comme on pourrait le croire.”) F
. 18 cons.ldered> by an historian of high reputation, as the reformer of Italian philosophy. If the execution of
cannot fail at all to thf enlightened views with which the design seems to nave been conceived, it
, , much practical utility. “ Ma chi pub veramente dirsi il riformatore dell’ Italiana filosofia, chi
la fece tosto conoscere, e respettare da’ pui dotti filosofi delle altre nazioni, chi seppe arricchire di nuovi pregi la logica, la
Gen°VeSi- , T«ttoche molti fossero stati i fihSofi die cercarono con "sottili riflfsSn"
g H, pye?ettl d ajutare la mente a pensare ed a ragionare con esattezza e verita, e Bacone, Malebranche, Loke, Wolfio,
e molt alto sembrassero avere esaunto quanto v’era da scrivere su tale arte, seppe nondimeno il Genovesi trovare nuove
Sofir^eneralminWd^n-11^ dH-Prep0ri-« 6 ^ Una lo?ica Piu Piena e comPil>ta, e piu utile non solo alio studio della
losofia, e generalmente ad ogm studio scientifico, ma eziandfo alia condotta morale, edalla civile societa Oriyine,
de Proyressi, e dello Stato attuale d Ogm Lctteratura dell’ Abate D. Giovanni Andres. Tomo XV. pp. 260. 261. Ve-
neziu, loUU*)
DISSERTATION FIRST.
203
part of Europe where mathematicians and me¬
taphysicians of the highest rank have produced
such poetry as has proceeded from the pens of
Boscovich and Stay. It is in this rare balance
of imagination, and of the reasoning powers,
that the perfection of the human intellect will
be allowed to consist; and of this balance a far
greater number of instances may be quoted from
Italy (reckoning from Galileo1 downwards), than
in any other corner of the learned world.
The sciences of ethics, and of political eco¬
nomy, seem to be more suited to the taste of the
modern Italians, than logic or metaphysics, pro¬
perly so called. And in the two former bran¬
ches of knowledge, they have certainly con¬
tributed much to the instruction and improve¬
ment of the eighteenth century. But on these
subjects we are not yet prepared to enter.
In the New World, the state of society and of
manners has not hitherto been so favourable to
abstract science as to pursuits which come home
directly to the business of human life. There
is, however, one metaphysician of whom Ame¬
rica has to boast, who, in logical acuteness and
subtility, does not yield to any disputant bred
in the universities of Europe. I need not say,
that I allude to Jonathan Edwards. But, at the
time when he wrote, the state of America was
more favourable than it now is, or can for a
long period be expected to be, to such inquiries
as those which engaged his attention; inquiries,
by the way, to which his thoughts were evi¬
dently turned, less by the impulse of speculative
curiosity, than by his anxiety to defend the theo¬
logical system in which he had been educated,
and to which he was most conscientiously and
zealously attached. The effect of this anxiety in
sharpening his faculties, and in keeping his pole*
mical vigilance constantly on the alert, may be
traced in every step of his argument.2
In the mean time, a new and unexpected
mine of intellectual wealth has been opened to
the learned of Europe, in those regions of the
East, which, although in all probability the
cradle of civilisation and science, were, till very
lately, better known in the annals of commerce
than of philosophy. The metaphysical and
ethical remains of the Indian sages are, in a pe¬
culiar degree, interesting and instructive; inas¬
much as they seem to have furnished the germs
of the chief systems taught in the Grecian schools.
The favourite theories, however, of the Hindoos
will, all of them, be found, more or less, tinc¬
tured with those ascetic habits of abstract and
mystical meditation which seem to have been, in
all ages, congenial to their constitutional tem¬
perament. Of such habits, an Idealism, ap¬
proaching to that of Berkeley and Malebranche,
is as natural an offspring, as Materialism is of
the gay and dissipated manners, which, in great
and luxurious capitals, are constantly inviting
the thoughts abroad.
To these remains of ancient science in the
1 See a most interesting account of Galileo’s taste for poetry and polite literature in Ginguend, Histoire Litter air e
d'ltalie. Tome V. pp. 331, et seq. a Paris, 1812.
2 While this Dissertation was in the press, I received anew American publication, entitled, “ Transactions of the Histori¬
cal and Literary Committee of the American Philosophical Society, held at Philadelphia, for Promoting Useful Knowledge," Vol. [.
Philadelphia, 1819. From an advertisement prefixed to this volume, it appears that, at a meeting of this learned body
in 1815, it was resolved, “ That a new committee be added to those already established, to be denominated the Committee
of History, Moral Science, and General Literature.” It was with great pleasure I observed, that one of the first objects
to which the committee has directed its attention is to investigate and ascertain, as much as possible, the structure and
grammatical forms of the languages of the aboriginal nations of America. The Report of the corresponding secretary (M.
Duponceau), dated January 1819, with respect to the progress then made in this investigation, is highly curious and inte¬
resting, and displays not only enlarged and philosophical views, but an intimate acquaintance with the philological re¬
searches of Adelung, Vater, Humboldt, and other German scholars. All this evinces an enlightened curiosity, and an ex¬
tent of literary information, which could scarcely have been expected in these rising states for many years to come.
The rapid progress which the Americans have lately made in the art of writing has been remarked by various critics,
and it is certainly a very important fact in the history of their literature. Their state papers were, indeed, always distin¬
guished by a strain of animated and vigorous eloquence; but as most of them were composed on the spur of the occasion,
their authors had little time to bestow on the niceties, or even upon the purity of diction. An attention to these is the slow
offspring of learned leisure, and of the diligent study of the best models. This I presume was Gray’s meaning, when he
said, that “good writing not only required great parts, but the very best of those parts —a maxim which, if true, would
point out the state of the public taste with respect to style, as the surest test among any people of the general improve¬
ment which their intellectual powers have received ; and which, when applied to our Trans-atlantic brethren, would justify
sanguine expectations of the attainments of the rising generation.
* Note of Mason on a Letter of Gray’s to Dr Wharton, on the death of Dr Middleton.
204
PRELIMINARY DISSERTATIONS.
East, the attention of Europe was first called by
Bernier, a most intelligent and authentic tra¬
veller, of whom I formerly took notice as a fa¬
vourite pupil of Gassendi. But it is chiefly hy
our own countrymen that the field which he
opened has been subsequently explored; and of
their meritorious labours in the prosecution of
this task, during the reign of our late Sovereign, it
is scarcely possible to form too high an estimate.
Much more, however, may he yet expected,
if such a prodigy as Sir William Jones should
again appear, uniting, in as miraculous a degree,
the gift of tongues with the spirit of philosophy.
The structure of the Sanscrit, in itself, indepen¬
dently of the treasures locked up in it, affords
one of the most puzzling subjects of inquiry
that was ever presented to human ingenuity.
The affinities and filiations of different tongues,
as evinced in their corresponding roots and
other coincidences, are abundantly curious, hut
incomparably more easy in the explanation, than
the systematical analogy which is said to exist
between the Sanscrit and the Greek (and also
between the Sanscrit and the Latin, which is
considered as the most ancient dialect of the
Greek), in the conjugations and flexions of their
verbs, and in many other particulars of their
mechanism ; an analogy which is represented as
so complete, that, in the versions which have
been made from the one language into the other,
“ Sanscrit,” we are told, “ answers to Greek,
as face to face in a glass.”1 That the Sanscrit
did not grow up to the perfection which it now
exhibits, from popular and casual modes of
speech, the unexampled regularity of its forms
seems almost to demonstrate; and yet, should
tliis supposition he rejected, to what other hypo¬
thesis shall we have recourse, which does not
involve equal, if not greater improbabilities ?
The problem is well worthy of the attention of
philosophical grammarians; and the solution of
it, whatever it may be, can scarcely fail to throw
some new lights on the history of the human
race, as well as on that of the human mind.
SECTION VIII.
Metaphysical Philosophy of Scotland.
It now only remains for me to take a slight
survey of the rise and progress of the Meta¬
physical Philosophy of Scotland; and if, in
treating of this, I should be somewhat more
minute than in the former parts of this Histo¬
rical Sketch, I flatter myself that allowances will
be made for my anxiety to supply some chasms
in the literary history of my country, which
could not he so easily, nor perhaps so authenti¬
cally, filled up by a younger hand.
The Metaphysical Philosophy of Scotland, and,
indeed, the literary taste in general, which so
remarkably distinguished this country during
the last century, may he dated from the lectures
of Dr Francis Hutcheson, in the University of
Glasgow. Strong indications of the same spe¬
culative spirit may be traced in earlier writers;2
hut it was from this period that Scotland, after
a long slumber, began again to attract general
notice in the republic of letters.3
The writings of Dr Hutcheson, however, are
more closely connected with the history of
Ethical than of Metaphysical Science; and I
1 Letter from the Reverend David Brown, Provost of the College of Fort William, about the Smscrit Edition of the
Gospels (dated Calcutta, September 1806, and published in some of the Literary Journals of the day.)
4 See Note B B B.
3 An Italian writer of some note, in a work published in 1763, assigns the same date to the revival of letters in Scotland.
‘ Fra i tanti, e si chiari Scrittori che fiorirono nella Gran Bretagna a’ tempi della Regina Anna, noh se ne conta pur uno,
DISSERTATION FIRST.
205
shall, accordingly, delay any remarks which I
have to offer upon them till I enter upon that
part of my subject. There are, indeed, some
very original and important metaphysical hints
scattered over his works; but it is chiefly as
an ethical writer that he is known to the world,
and that he is entitled to a place among the
philosophers of the eighteenth century.1
Among the contemporaries of Dr Hutcheson,
there was one Scottish metaphysician (Andrew
Baxter, author of the Inquiry into the Nature of
the Human SoulJ, whose name it would be im¬
proper to pass over without some notice, after
the splendid eulogy bestowed on his work by
Warburton. “ He who would see the justest
and precisest notions of God and the soul may
read this book, one of the most finished of the
kind, in my humble opinion, that the present
times, greatly advanced in true philosophy, have
produced”2
To this unqualified praise, I must confess, I
do not think Baxter’s Inquiry altogether entitled,
although I readily acknowledge that it displays
considerable ingenuity, as well as learning.
Some of the remarks on Berkeley’s argument
against the existence of matter are acute and
just, and, at the time when they were published,
had the merit of novelty.
One of his distinguishing doctrines is, that
the Deity is the immediate agent in producing
the phenomena of the Material World ; but that,
in the Moral World, the case is different,—a
doctrine which, whatever may be thought of it
in other respects, is undoubtedly a great im¬
provement on that of Malebranche, which, by
representing God as the only agent in the uni¬
verse, was not less inconsistent than the scheme
of Spinoza with the moral nature of Man. “ The
Deity (says Baxter) is not only at the bead of
Nature, but in every part of it. A chain of
material causes betwixt the Deity and the effect
produced, and much more a series of them, is
such a supposition as would conceal the Deity
from the knowledge of mortals for ever. We
might search for matter above matter, till we
were lost in a labyrinth out of which no phi¬
losopher ever yet found his way.—This way of
bringing in second causes is borrowed from the
government of the moral world, where free
agents act a part; but it is very improperly ap-
che sia uscito di Scozia Francesco Hutcheson venuto in Iscozia, a professarvi la Filosofia, e gli studii di umanith,
nella Universita di Glasgow, v’insinuo per tutto il paese colie istruzione a viva voce, e con egregie opere date alle stampe,
un vivo genio per gli studii filosofici, e literarii, e sparse qui fecondissimi semi, d’onde vediamo nascere si felice frutti, e si
copiose.”—(Discorso sopra le Vicende della Litteratura, del Sig. Carlo Denina, p. 224, Glasgow edit. 1763.)
I was somewhat surprised to meet with the foregoing observations in the work of a foreigner ; but, wherever he acquired
his information, it evinces, in those from whom it was derived, a more intimate acquaintance with the traditionary history
of letters in this country than has fallen to the share of most of our own authors who have treated of that subject. I have
heard it conjectured, that the materials of his section on Scottish literature had been communicated to him by Mr Hume.
Another foreign writer, much better qualified than Denina to appreciate the merits of Hutcheson, has expressed him¬
self upon this subject with his usual precision. “ L’ecole Ecossaise a en quelque sorte pour fondateur Hutcheson, mailre
et predecesseur de Smith. C’est ce philosophe qui lui a imprimb son caractere, et qui a commence a lui donner de
Teclat.” In a note upon this passage, the author observes,—“ C’est en ce seal sens qu’on peut donner un chef a une
bcole de philosophic qui, comme on le verra, professe d’ailleurs la plus parfaite inddpendance de I’autoritb—(See the
excellent reflections upon the posthumous works of Adam Smith, annexed by M. Prevost to his translation of that
work.)
Dr Hutcheson’s first course of lectures at Glasgow was given in 1730. He was a native of Ireland, and is accord¬
ingly called by Denina “ un dotto Irlandesebut he was of Scotch extraction (his father or grandfather having been a
younger son of a respectable family in Ayrshire), and he was sent over when very young to receive his education in
Scotland.
1 One of the chief objects of Hutcheson’s writings was to oppose the licentious system of Mandeville; a system
which was the natural offspring of some of Locke’s reasonings against the existence of innate practical principles.
As a moralist, Hutcheson was a warm admirer of the ancients, and seems to have been particularly smitten with
that favourite doctrine of the Socratic school which identifies the good with the beautiful. Hence he was led to follow
much too closely the example of Shaftesbury, in considering moral distinctions as founded more on sentiment than
on reason, and to speak vaguely of virtue as a sort of noble enthusiasm; but he was led, at the same time, to connect
with his ethical speculations some collateral inquiries concerning Beauty and Harmony, in which he pursued, with con¬
siderable success, the path recently struck out by Addison in his Essays on the Pleasures of the Imagination. These in¬
quiries of Hutcheson, together with his Thoughts on Laughter, although they may not be very highly prized for their
depth, bear everywhere the marks of an enlarged and cultivated mind, and, whatever may have been their effects else¬
where, certainly contributed powerfully, in our Northern seats of learning, to introduce a taste for more liberal and
elegant pursuits than could have been expected so soon to succeed to the intolerance, bigotry, and barbarism of the
preceding century.
1 See Warburton’s Divine Legation of Moses demonstrated, p. 395 of the first edition.
206
PRELIMINARY DISSERTATIONS.
plied to the material universe, where matter and
motion only (or mechanism, as it is called) comes
in competition with the Deity.”1 2 3 * * * *
Notwithstanding, however, these and other
merits, Baxter has contributed so little to the
advancement of that philosophy which has since
been cultivated in Scotland, that I am afraid the
very slight notice I have now taken of him may
be considered as an unseasonable digression.
The great object of his studies plainly was, to
strengthen the old argument for the soul’s im¬
materiality, by the new lights furnished by New¬
ton’s discoveries. To the intellectual and moral
phenomena of Man, and to the laws by which
they are regulated, he seems to have paid hut
little attention.®
While Dr Hutcheson’s reputation as an au¬
thor, and still more as an eloquent teacher, was
at its zenith in Scotland, Mr Hume began his
literary career, by the publication of his Treatise
of Human Nature. It appeared in 1739, but
seems at that time to have attracted little or no
attention from the public. According to the
author himself, “ never literary attempt was
more unfortunate. It fell dead-born from the
press, without reaching such distinction as even
to excite a murmur among the zealots.” It
forms, however, a very important link in this
Historical Sketch, as it has contributed, either
directly or indirectly, more than any other single
work, to the subsequent progress of the Philo¬
sophy of the Human Mind. In order to adapt
his principles better to the public taste, the author
afterwards threw them into the more popular
form of Essays; but it is in the original work
that philosophical readers will always study his
system, and it is there alone that the relations
and bearings of its different parts, as well as its
connection with the speculations of his imme¬
diate predecessors, can be distinctly traced. It
is there, too, that his metaphysical talents ap¬
pear, in my opinion, to the greatest advantage;
nor am I certain that he has anywhere else dis¬
played more skill or a sounder taste in point of
composition.8
The great objects of Mr Hume’s Treatise of
1 Appendix to the first part of the Inquiry into the Nature of the Human Soul, pp. 109, 110.
2 Baxter was born at Old Aberdeen, in 1686 or 1687, and died at Whittingham, in East Lothian, in 1750. I have not
been able to discover the date of the first edition of his Inquiry into the Nature of the Human Soul, but the second edition ap¬
peared in 1737, two years before the publication of Mr Hume’s Treatise of Human Nature.
3 A gentleman, who lived in habits of great intimacy with Dr Held towards the close of his life, and on whose accuracy
I can fully depend, remembers to have heard him say repeatedly, that “ Mr Hume, in his Essays, appeared to hwe forgot¬
ten his Metaphysics.” Nor will this supposition be thought improbable, if, in addition to the subtle and fugitive nature of
the subjects canvassed in the Treatise of Human Nature, it be considered that long before the publication of his Essays, Mr
Hume had abandoned all his metaphysical researches. In proof of this, I shall quote a passage from a letter of his to Sir
Gilbert Elliot, which, though without a date, seems from its contents to have been written about 1750 or 1751. The pas¬
sage is interesting on another account, as it serves to show how much Mr Hume undervalued the utility of mathematical
learning, and consequently how little he was aware of its importance, as an organ of physical discovery, and as the founda¬
tion of some of the most necessary arts of civilised life. “ I am sorry that our correspondence should lead us into these ab¬
stract speculations. I have thought, and read, and composed very little on such questions of late. Morals, politics, and
literature, have employed all my time ; but still the other topics I must think more curious, important, entertaining, and
useful, than any geometry that is deeper than Euclid.”
I have said that it is in Mr Hume’s earliest work that his metaphysical talents appear, in my opinion, to the greatest
advantage. From the following advertisement, however, prefixed, in the latest editions of his works, to the second volume
of his Essays and Treatises, Mr Hume himself would appear to have thought differently. “Most of the principles and rea¬
sonings contained in this volume were published in a work in three volumes, called A Treatise of Human Nature ; a work
which the author had projected before he left College, and which he wrote and published not long after. But not finding
it successful, he was sensible of his error in going to the press too early, and he cast the whole anew in the following pieces,
where some negligencies in his former reasoning, and some in the expression, are, he hopes, corrected. Yet several wri¬
ters, who have honoured the author’s philosophy with answers, have taken care to direct all their batteries against that ju¬
venile work, which the author never acknowledged, and have affected to triumph in any advantage which they imagined
they had obtained over it; a practice very contrary to all rules of candour and fair dealing, and a strong instance of those
polemical artifices which a bigoted zeal thinks itself authorised to employ. Henceforth, the author desires, that the follow¬
ing pieces may alone be regarded as containing his philosophical sentiments and principles.”
After this declaration, it certainly would be highly uncandid to impute to Mr Hume any philosophical sentiments or
principles not to be found in his Philosophical Essays, as well as in his Treatise. But where is the unfairness of replying to any
plausible arguments in the latter work, even although Mr Hume may have omitted them in his subsequent publications ;
more especially where these arguments supply any useful lights for illustrating his more popular compositions ? The
Treatise of Human Nature will certainly be remembered as long as any of Mr Hume’s philosophical writings ; nor is any
person qualified either to approve or to reject his doctrines, who has not studied them in the systematical form in which
they were originally cast. That Mr Hume’s remonstrance may be just with respect to some of his adversaries, I believe
to be true ; but it is surely expressed in a tone more querulous and peevish than is justified by the occasion.
I shall take this opportunity of preserving another judgment of Mr Hume’s (still more fully stated) on the merits of this
DISSERTATION FIRST.
207
Human Nature will be best explained in his own
words.
“ ’Tis evident that all the sciences have a re¬
lation, greater or less, to human nature, and
that, however wide any of them may seem to
run from it, they still return back by one pas¬
sage or another. Even Mathematics, Natural
Philosophy, and Natural Religion, are in some
measure dependent on the science of Man, since
they lie under the cognisance of men, and are
judged of by their powers and faculties 
If, therefore, the sciences of Mathematics, Na¬
tural Philosophy, and Natural Religion, have
such a dependence on the knowledge of man,
what may be expected in the other sciences,
whose connection with human nature is more
close and intimate ? The sole end of logic is to
explain the principles and operations of our rea¬
soning faculty, and the nature of our ideas:
Morals and criticism regard our tastes and sen¬
timents, and politics consider men as united in
society, and dependent on each other 
Here, then, is the only expedient from which
we can hope for success in our philosophical re¬
searches, to leave the tedious lingering method
which we have hitherto followed, and, instead
of taking now and then a castle or village on
the frontier, to march up directly to the capital
or centre of these sciences, to human nature it¬
self; which, being once masters of, we may
everywhere else hope for an easy victory. From
this station we may extend our conquests over
all those sciences which more intimately concern
human life, and may afterwards proceed at lei¬
sure to discover more fully those which are the
objects of pure curiosity. There is no question
of importance whose decision is not comprised
in the Science of Man, and there is none which
can be decided with any certainty before we be¬
come acquainted with that science. In pre¬
tending, therefore, to explain the principles of
Human Nature, we, in effect, propose a com¬
plete system of the sciences, built on a foun¬
dation almost entirely new, and the only one
upon which they can stand with any security.
“ And, as the science of man is the only solid
foundation for the other sciences, so the only
solid foundation we can give to this science it¬
self must be laid on experience and observa¬
tion. ’Tis no astonishing reflection to consider,
that the application of experimental philosophy
to moral subjects should come after that to na¬
tural, at the distance of above a whole century;
since we find, in fact, that there was about the
same interval betwixt the origin of these sci¬
ences ; and that, reckoning from Thales to So¬
crates, the space of time is nearly equal to that
hetwixt my Lord Bacon and some late philoso¬
phers in England,1 who have begun to put the
science of man on a new footing, and have en¬
gaged the attention, and excited the curiosity of
the public.”
I am far from thinking, that the execution of
Mr Hume’s work corresponded with the mag¬
nificent design sketched out in these observa¬
tions ; nor does it appear to me that he had form¬
ed to himself a very correct idea of the manner
in which the experimental mode of reasoning
ought to be applied to moral subjects. He had,
however, very great merit in separating entire¬
ly his speculations concerning the philosophy of
the mind from all physiological hypotheses about
the nature of the union between soul and body;
and although, from some of his casual expres¬
sions, it may be suspected that he conceived our
intellectual operations to result from bodily or¬
ganisation, 2 he had yet much too large a share of
good sense and sagacity to suppose, that, by study-
juvenile work. I copy it from a private letter written by himself to Sir Gilbert Elliot, soon after the publication of his
Philosophical Essays. 1
“ I believe the Philosophical Essays contain every thing of consequence relating to the Understanding, which you would
meet with in the Treatise ; and I give you my advice against reading the latter. By shortening and simplifying the ques¬
tions, I really render them more complete. Addo dum minuo. The philosophical principles are the same in both; but I was
carried away by the heat of youth and invention to publish too precipitately. So vast an undertaking, planned before I was
one and twenty, and composed before twenty-five, must necessarily be very defective. I have repented my haste a hun¬
dred and a hundred times.” " v j
1 “Mr Locke, Lord Shaftesbury, Dr Mandeville, Mr Hutcheson, Dr Butler,” &c.
I he only expression in his works I can recollect at present, that can give any reasonable countenance to such a suspi¬
cion, occuis in his Posthumous Dialogues^ where he speaks of 44 that little agitation of the brain which we call thought”
(2d Edition, pp. G9, 61.) But no fair inference can be drawn from this, as the expression is put into the mouth of Philo
the Sceptic ; whereas the author intimates that Cleanthes speaks his own sentiments.
208
PRELIMINARY DISSERTATIONS.
ing the latter, it is possible for human ingenuity
to throw any light upon the former. His woiks,
accordingly, are perfectly free from those gia-
tuitous and wild conjectures, which a few years
afterwards were given to the world with so much
confidence by Hartley and Bonnet. And in this
respect his example has been of infinite use to
his successors in this northern part of the island.
Many absurd theories have, indeed, at different
times been produced by our countrymen 5 but I
know of no part of Europe where such systems
as those of Hartley and Bonnet have been so
uniformly treated with the contempt they de¬
serve as in Scotland.1
Nor was it in this respect alone, that Mr
Hume’s juvenile speculations contributed to for¬
ward the progress of our national literature.
Among the many very exceptionable doctrines
involved in them, there are various discussions,
equally refined and solid, in which he has hap¬
pily exemplified the application of metaphysical
analysis to questions connected with taste, with
the philosophy of jurisprudence, and with the
theory of government. Of these discussions
some afterwards appeared in a more popular
form in his philosophical and literary Essays,
and still retain a place in the latest editions of
his works; but others, not less curious, have
been suppressed by the author, probably from
an idea, that they were too abstruse to interest
the curiosity of ordinary readers. In some of
these practical applications of metaphysical
principles, we may perceive the germs of several
inquiries which have since been successfully
prosecuted by Mr Hume’s countrymen; and,
among others, of those which gave birth to Lord
Karnes’s Historical Law Tracts, and to his Ele¬
ments of Criticism.
The publication of Mr Hume’s Treatise was
attended with another important effect in Scot¬
land. He had cultivated the art of writing with
much greater success than any of his predeces¬
sors, and had formed his taste on the best models
of English composition. The influence of his
example appears to have been great and gene¬
ral ; and was in no instance more remarkable
than in the style of his principal antagonists, all
of whom, in studying his system, have caught,
in no inconsiderable degree,- the purity, polish,
and precision of his diction. Nobody, I believe,
will deny, that Locke himself, considered as an
English writer, is far surpassed, not only by
Hume, but by Reid, Campbell, Gerard, and
Beattie; and of this fact it will not be easy to
find a more satisfactory explanation, than in the
critical eye with which they were led to canvass
a work, equally distinguished by the depth of
its reasonings, and by the attractive form in
which they are exhibited.
The fundamental principles from which Mr
Hume sets out, differ more in words than in
substance from those of his immediate prede¬
cessors. According to him, all the objects of
our knowledge are divided into two classes, im¬
pressions and ideas : the former, comprehending
our sensations, properly so called, and also our
perceptions of sensible qualities (two things be¬
twixt which Mr Hume’s system does not lead
him to make any distinction); the latter, the
objects of our thoughts when we remember or
imagine, or in general exercise any of our intel¬
lectual powers on things which are past, ab¬
sent, or future. These ideas he considers as
copies of ouf impressions, and the words which
denote them as the only signs entitled to the at¬
tention of a philosopher ; every word professing
to denote an idea, of which the corresponding
impressions cannot be pointed out, being ipso
facto unmeaning and illusory. The obvious re¬
sult of these principles is, that what Mr Hume
calls impressions, furnish, either immediately or
mediately, the whole materials about which our
thoughts can be employed; a conclusion coin¬
ciding exactly with the account of the origin of
our ideas borrowed by Gassendi from the an¬
cient Epicureans.
With this fundamental principle of the Gas-
sendists, Mr Hume combined the logical method
recommended by their great antagonists the
Cartesians, and (what seemed still more remote
from his Epicurean starting ground) a strong
leaning to the idealism of Malebranche and of
1 In no part of Mr Hume’s metaphysical writings is there the slightest reference to either of these systems, although he
survived the date of their publication little less than thirty years.
DISSERTATION FIRST.
209
Berkeley. Like Descartes, he began with doubt¬
ing of every thing, but he was too quick-sighted
to be satisfied, like Descartes, with the solutions
given by that philosopher of his doubts. On
the contrary, he exposes the futility not only of
the solutions proposed by Descartes himself, but
of those suggested by Locke and others among
his successors ; ending at last where Descartes
beg^n, in considering no one proposition as more
certain, or even as more probable than another.
That the proofs alleged by Descartes of the ex¬
istence of the material world are quite incon¬
clusive, had been already remarked by many.
Nay, it had been shown by Berkeley and others,
that if the principles be admitted on which Des¬
cartes, in common with all philosophers, from
Aristotle downwards, proceeded, the existence
of the material world is impossible. A few bold
thinkers, distinguished by the name of Egoists,
had gone still farther than this, and had pushed
their scepticism to such a length, as to doubt
of everything but their own existence. Accord¬
ing to these) the proposition, eogito, ergo sum, is
the only truth which can be regarded as abso¬
lutely certain. It was reserved for Mr Hume
to call in question even this proposition, and to
admit only the existence of impressions and ideas.
To dispute against the existence of these he
conceived to be impossible, inasmuch as they
are the immediate subjects of consciousness.
But to admit the existence of the thinking and
percipient I, was to admit the existence of that
imaginary substance called Mind, which (ac¬
cording to him) is no more an object of human
knowledge, than the imaginary and exploded
substance called Matter.
From what has been already said, it may be
seen, that we are not to look in Mr Hume’s
Treatise for any regular or connected system.
It is neither a scheme of Materialism, nor a
scheme of Spiritualism; for his reasonings strike
equally at the root of both these theories. His
aim is to establish a universal scepticism, and
to produce in the reader a complete distrust in
his own faculties. For this purpose he avails
himself of the data assumed by the most op¬
posite sects, shifting his ground skilfully from
one position to another, as best suits the scope
of his present argument. With the single ex¬
ception of Bayle, he has carried this sceptical
mode of reasoning farther than any other mo¬
dern philosopher. Cicero, who himself belong¬
ed nominally to the same school, seems to have
thought, that the controversial habits imposed
on the Academical sect by their profession of
universal doubt, required a greater versatility of
talent and fertility of invention, than were ne¬
cessary for defending any particular system of
tenets;1 and it is not improbable, that Mr Hume,
in the pride of youthful genius, was misled by
this specious but very fallacious idea. On the
other hand, Bayle has the candour to acknow¬
ledge, that nothing is so easy as to dispute after
the manner of the sceptics;2 3 * and to this propo¬
sition every man of reflection will find himself
more and more disposed to assent, as he ad¬
vances in life. It is experience alone that can
convince us, how much more difficult it is to
make any real progress in the search after
truth, than to acquire a talent for plausible dis¬
putation.5
That this spirit of sceptical argument has been
1 “ Nam si singulas disciplinas percipere magnum est, quanto majus omnes ? quod facere iis necesse est, quibus proposi-
tum est, veri reperiendi causa, et contra omnes philosophos et pro omnibus dicere—Cujus rei tantse tamque dimcilis xacul-
tatem consecutum esse me non profiteer: Secutum esse prae me fero.”—(Cicero Be Nat. Dear. 1. i. v.)
2 See the passage quoted from Bayle, in page 86 of this Dissertation. _
3 In the very interesting account, given by Dr Holland, of Velara, a modern Greek physician, whom he met with at-La-
rissa in Thessaly, a few slight particulars are mentioned, which let us completely into the character of that ingenious per¬
son. “ It appeared,” says Dr Holland, “ that Velara had thought much on the various topics of Metaphysics and Morals,
and his conversation on these topics bore the same tone of satirical scepticism which was apparent as the general feature o
his opinions. We spoke of the questions of Materialism and Necessity, on both of which he declared an affirmative opi¬
nion.”—(Holland’s Travels in the Ionian Isles, See. p. 275.) “ I passed this evening with Velara at his own house, and sat
with him till a late hour. During part of the time our conversation turned upon metaphysical topics, and chiefly on the
old Pyrrhonic doctrine of the non-existence of Matter. Velara, as usual, took the sceptical side of the argument, in w ^ic
he showed much ingenuity and great knowledge of the more eminent controversialists on this and other collateral subjec s. -
CIbid. p. 370.) We see here a lively picture of a character daily to be met with in more polished and learned societies, dis¬
puting not for truth but for victory; in the first conversation professing himself a Materialist; and in the secon enyin0
the existence of Matter ; on both occasions, taking up that ground where he was most likely to provoke opposi ion.
inference is to be drawn from the conversation of such an individual, with respect to his real creed, it is m avour o ose
DISS. I. PART II. ^ U
210
PRELIMINARY DISSERTATIONS.
carried to a most pernicious excess in modern
Europe, as well as among the ancient Academics,
will, I presume, be now very generally allowed;
but in the form in which it appears in Mr Hume’s
Treatise.) its mischievous tendency has been more
than compensated by the importance of those re¬
sults for which it has prepared the way. The
principles which he assumes were sanctioned in
common by Gassendi, by Descartes, and by
Locke; and from these, in most instances, he
reasons with great logical accuracy and force.
The conclusions to which he is thus led are often
so extravagant and dangerous, that he ought to
have regarded them as a proof of the unsoundness
of his data; hut if he had not the merit of draw¬
ing this inference himself, he at least forced it
so irresistibly on the observation of his successors,
as to he entitled to share with them in the ho¬
nour of their discoveries. Perhaps, indeed, it
may he questioned if the errors which he adopted
from his predecessors would not have kept their
ground till this day, had not his sagacity display¬
ed so clearly the consequences which they ne¬
cessarily involve. It is in this sense that we
must understand a compliment paid to him by
the ablest of his adversaries, when he says, that
“ Mr Hume’s premises often do more than atone
for his conclusions.”1
The bias of Mr Hume’s mind to scepticism
seems to have been much encouraged, and the
success of his sceptical theories in the same pro¬
portion promoted, by the recent attempts of
Descartes and his followers to demonstrate Self-
evident Truths;—attempts which Mr Hume
clearly perceived to involve, in every instance,
that sort of paralogism which logicians call rea¬
soning in a circle. The weakness of these pre¬
tended demonstrations is triumphantly exposed
in the Treatise of Human Nature ; and it is not
very wonderful that the author, in the first en¬
thusiasm of his victory over his immediate pre-.
decessors, should have fancied that the incon¬
clusiveness of the proofs argued some unsound¬
ness in the propositions which they were em¬
ployed to support. It would, indeed, have done
still greater honour to his sagacity if he had as¬
cribed this to its true cause—the impossibility
of confirming, by a process of reasoning, the
fundamental laws of human belief; hut (as Bacon
remarks) it does not often happen to those who
labour in the field of science, that the same per¬
son who sows the seed should reap the harvest.
From that strong sceptical bias which led this
most acute reasoner, on many important ques¬
tions, to shift his controversial ground according
to the humour of the moment, one favourable
consequence has resulted—that we are indebted
to him for the most powerful antidotes we pos¬
sess against some of the most poisonous errors
of modern philosophy. I have already made a
similar remark in speaking of the elaborate re¬
futation of Spinozism by Bayle; but the argu¬
ment stated by Hume, in his Essay on the Idea
of Necessary Connection (though brought forward
by the author with a very different view), forms
a still more valuable accession to metaphysical
science, as it lays the axe to the very root from
which Spinozism springs. The cardinal prin¬
ciple on which the whole of that system turns
is, that all events, physical and moral, are ne¬
cessarily linked together as causes and effects;
from which principle all the most alarming con¬
clusions adopted by Spinoza follow as unavoid¬
able and manifest corollaries. But, if it be true,
as Mr Hume contends, and as most philosophers
now admit, that physical causes and effects are
known to us merely as antecedents and conse¬
quents ; still more, if it be true that the word ne¬
cessity, as employed in this discussion, is alto¬
gether unmeaning and insignificant, the whole
system of Spinoza is nothing better than a rope
of sand, and the very proposition which it pro¬
opinions which he controverts. These opinions, at least, we may confidently conclude to he agreeable to the general belief
of the country where he lives. ^ ^ ^ & &
1 Mr Hume himself (to whom Dr Reid’s Inquiry was communicated previous to its publication, by their common friend
Dr Blair) seems not to have been dissatisfied with this apology for some of his speculations. u I shall only say (he ob-
serves in a letter addressed to the author), that if you have been able to clear up these abstruse and important subjects,
instead of being mortified, I shall be so vain as to pretend to a share of the praise, and shall think that my errors, by hav¬
ing at least some coherence, had led you to make a more strict review of my principles, which were the common ones, and
to perceive their futility. —(For the whole of Mr Hume’s letter, see Biographical Memoirs of Smith, Robertson, and Reid,
by the author of this Dissertation, p. 417-)
DISSERTATION FIRST.
211
fesses to demonstrate is incomprehensible by our
faculties. Mr Hume’s doctrine, in the unquali¬
fied form in which he states it, may lead to other
consequences not less dangerous : but, if he had
not the good fortune to conduct metaphysicians
to the truth, he may at least be allowed the merit
of haying shut up for ever one of the most fre¬
quented and fatal paths which led them astray.
In what I have now said, I have supposed my
readers to possess that general acquaintance with
Mr Hume’s Theory of Causation which all well-
educated persons may he presumed to have ac¬
quired. But the close connection of this part of
his work with some of the historical details which
are immediately to follow, makes it necessary
for me, before I proceed farther, to recapitulate
a little more particularly some of his most im¬
portant conclusions.
It was, as far as I know, first shown in a sa¬
tisfactory manner by Mr Hume, that “ every de¬
monstration which has been produced for the ne¬
cessity of a cause to every new existence, is fal¬
lacious and sophistical.”1 In illustration of this
assertion, he examines three different arguments
which have been alleged as proofs of the propo¬
sition in question; the first by Mr Hobbes; the
second by Dr Clarke; and the third by Mr
Locke. And I think it will now be readily ac¬
knowledged by every competent judge, that his
objections to all these pretended demonstrations
are conclusive and unanswerable.
When Mr Hume, however, attempts to show
that the proposition in question is not intuitively
certain, his argument appears to me to amount
to nothing more than a logical quibble. Of this
one would almost imagine that he was not in¬
sensible himself, from the short and slight man¬
ner in which he hurries over the discussion.
££ All certainty (he observes) arises from the
comparison of ideas, and from the discovery of
such relations as are unalterable, so long as the
ideas continue the same. These relations are
resemblance, proportions in quantity and number,
degrees of any quality, and contrariety ; none of
which are implied in this proposition, whatever
has a beginning has also a cause of existence. That
proposition, therefore, is not intuitively certain.
At least, any one who would assert it to be in¬
tuitively certain, must deny these to be the only
infallible relations, and must find some other
relation of that kind to be implied in it, which
it will be then time enough to examine.”
Upon this passage, it is sufficient for me to
observe, that the whole force of the reasoning
hinges on two assumptions, which are not only
gratuitous, but false. 1st, That all certainty
arises from the comparison of ideas. 2dly, That
all the unalterable relations among our ideas are
comprehended in his own arbitrary enumeration;
Resemblance, proportions in quantity and number,
degrees of any quality, and contrariety. When
the correctness of these two premises shall be
fully established, it will be time enough (to bor¬
row Mr Hume’s own words) to examine the just¬
ness of his conclusion.
From this last reasoning, however, of Mr
Hume, it may be suspected, that he was aware
of the vulnerable point against which his adver¬
saries were most likely to direct their attacks.
From the weakness, too, of the entrenchments
which he has here thrown up for his own secu¬
rity, he seems to have been sensible, that it was
not capable of a long or vigorous resistance. In
the mean time, he betrays no want of confidence
in his original position; but repeating his as¬
sertion, that “ we derive the opinion of the ne¬
cessity of a cause to every new production,
neither from demonstration nor from intuition,”
he boldly concludes, that “ this opinion must
necessarily arise from observation and experi¬
ence.”—(Vol. I. p. 147.) Or, as he elsewhere
expresses himself, “ All our reasonings concern¬
ing causes and effects are derived from nothing
but custom; and, consequently, belief is more
Treatise of Human Nature, Vol. I. p. 144—Although Mr Hume, however, succeeded better than any of his predeces-
sors, m calling the attention of philosophers to this discussion, his opinion on the subject does not possess the merit, in
point of originality, which was supposed to belong to it either by himself or by his antagonists. See the passages which I
lave quoted in proof of this, in the first volume of the Philosophy of the Human Mind, p. 542. et seq. fourth edit, and also in
the second volume of the same work, p. 556. et seq. second edit. Among these, I request the attention of my readers more
particularly to a passage from a book entitled, The Procedure, Extent, and Limits of the Human Understanding, published two
years before the Treatise of Human Nature, and commonly ascribed to Dr Browne, Bishop of Cork. The coincidence is
ruly wonderful, as it can scarcely, by any possibility, be supposed that this book was ever heard of by Mr Hume.
212
PRELIMINARY DISSERTATIONS.
properly an act of the sensitive than of the cogi¬
tative part of our natures.”—[Ibid. p. 321.)
The distinction here alluded to between the
sensitive and the cogitative parts of our nature (it
may be proper to remind my readers) makes a
great figure in the works of Cudworth and of
Kant. By the former it was avowedly borrowed
from the philosophy of Plato. To the latter, it
is not improbable, that it may have been sug¬
gested by this passage in Hume. Without dis¬
puting its justness or its importance, I may be
permitted to express my doubts of the propriety
of stating, so strongly as has frequently been
done, the one of these parts of our nature in
contrast with the other. Would it not be more
philosophical, as well as more pleasing, to con¬
template the beautiful harmony between them,
and the gradual steps by which the mind is train¬
ed by the intimations of the former, for the de¬
liberate conclusions of the latter? If, for example,
our conviction of the permanence of the laws
of nature be not founded on any process of
reasoning (a proposition which Mr Hume seems
to have established with demonstrative evidence),
but be either the result of an instinctive principle
of belief, or of the association of ideas, opera¬
ting at a period when the light of reason has not
yet dawned, what can be more delightful than
to find this suggestion of our sensitive frame.)1
verified by every step which our reason afterwards
makes in the study of physical science ; and con¬
firmed with mathematical accuracy by the never-
failing accordance of the phenomena of the
heavens with the previous calculations of astro¬
nomers ! Does not this afford a satisfaction to
the mind, similar to what it experiences, when
we consider the adaptation of the instinct of suc¬
tion, and of the organs of respiration, to the
physical properties of the atmosphere ? So far
from encouraging scepticism, such a view of hu¬
man nature seems peculiarly calculated to silence
every doubt about the veracity of our faculties.2
It is not my business at present to inquire
into the soundness of Mr Hume’s doctrines on
this subject. The rashness of some of them has,
in my opinion, been sufficiently shown by more
than one of his antagonists. I wish only to re¬
mark the important step which he made, in ex¬
posing the futility of the reasonings by which
Hobbes, Clarke, and Locke, had attempted to
demonstrate the metaphysical axiom, that “every
thing which begins to exist must have a cause;”
and the essential service which he rendered to
true philosophy, by thus pointing out indirectly
1 Upon either of these suppositions, Mr Hume would, with equal propriety, have referred our anticipation of the future
event to the sensitive part of our nature; and, in point of fact, the one supposition would have answered his purpose as well
as the other.
2 It is but justice to Mr Hume to remark, that, in his later publications, he has himself suggested this very idea as the
best solution he could give of his own doubts. The following passage, which appears to me to be eminently philosophical
and beautiful, I beg leave to recommend to the particular attention of Kant’s disciples :—
“ Here, then, is a kind of pre-established harmony between the course of nature and the succession of our ideas ; and
though the powers and forces by which the former is governed be wholly unknown to us, yet our thoughts and conceptions
have still, we find, gone on in the same train with the other works of nature. Custom is that principle by which this cor¬
respondence has been effected ; so necessary to the subsistence of our species, and the regulation of our conduct in every
circumstance and occurrence of human life. Had not the presence of an object instantly excited the idea of those objects
commonly conjoined with it, all our knowledge must have been limited to the narrow sphere of our memory and senses; and
we should never have been able to adjust means to ends, or employ our natural powers, either to the producing of good, or
avoiding of evil. Those who delight in the discovery and contemplation of final causes have here ample subject to employ
their wonder and admiration.
“ I shall add, for a further confirmation of the foregoing theory, that, as this operation of the mind, by which we infer
like effects from like causes, and vice versa, is so essential to the subsistence of all human creatures, it is not probable that
it could be trusted to the fallacious deductions of our reason, which is slow in its operations, appears not in any degree
during the first years of infancy, and at best is, in every age and period of human life, extremely liable to error and mis¬
take. It is more conformable to the ordinary wisdom of nature to secure so necessary an act of the mind by some in¬
stinct or mechanical tendency which may be infallible in its operations, may discover itself at the first appearance of life
and thought, and may be independent of all the laboured deductions of the understanding. As nature has taught us the
use of our limbs, without giving us the knowledge of the muscles and nerves by which they are actuated, so has she im¬
planted in us an instinct which carries forward the thoughts in a correspondent course to that which she has established
among external objects; though we are ignorant of those powers and forces on which this regular course and succession of
objects totally depends.”—(See, in the last editions of Mr Hume’s Philosophical Essays, published during his own lifetime,
the two sections entitled Sceptical Doubts concerning the Operations of the Understanding ; and Sceptical Solution of these Doubts.
The title of the latter ot these sections has, not altogether without reason, incurred the ridicule of Dr Beattie, who
translates it, Doubtful Solution of Doubtful Doubts. But the essay contains much sound and important matter, and throws
a strong light on some of the chief difficulties which Mr Hume himself had started. Sufficient justice has not been done
to it by his antagonists.)
DISSERTATION FIRST.
213
to his successors the only solid ground on which
that principle is to be defended. It is to this
argument of Hume’s, according to Kant’s own
acknowledgment, that we owe the Critique of
Pure Reason; and to this we are also indebted
for the far more luminous refutations of scep¬
ticism by Mr Hume’s own countrymen.
In the course of Mr Hume’s very refined dis¬
cussions on this subject, he is led to apply them
to one of the most important principles of the
mind,—-our belief of the continuance of the laws
of nature; ur, in other words, our belief that
the future course of nature will resemble the
past. And here, too (as I already hinted), it is
very generally admitted, that he has succeeded
completely in overturning all the theories which
profess to account for this belief, by resolving it
into a process of reasoning.1 The only differ¬
ence which seems to remain among philosophers
is, whether it can be explained, as Mr Hume
imagined, by means of the association of ideas;
or, whether it must be considered as an original
and fundamental law of the human understand¬
ing ;—a question, undoubtedly abundantly curi¬
ous, as a problem connected with the Theory of the
Mind ; hut to which more practical importance
has sometimes been attached than I conceive
to be necessary.2
That Mr Hume himself conceived his refuta¬
tion of the theories which profess to assign a
reason for our faith in the permanence of the laws
of nature, to he closely connected with his scep¬
tical conclusions concerning causation, is quite
evident from the general strain of his argument;
and it is, therefore, not surprising that this re¬
futation should have been looked on with a sus¬
picious eye by his antagonists. Dr Reid was, I
believe, the first of these who had the sagacity
to perceive, not only that it is strictly and in-
controvertibly logical, but that it may he safely
admitted, without any injury to the doctrines
which it was brought forward to subvert.
Another of Mr Hume’s attacks on these doc¬
trines was still bolder and more direct. In con¬
ducting it he took his vantage ground from his
own account of the origin of our ideas. In this
way he was led to expunge from his Philosophi¬
cal Vocabulary every word of which the mean¬
ing cannot he explained by a reference to the
impression from which the corresponding idea was
originally copied. Nor was he startled in the
application of this rule, by the consideration,
that it would force him to condemn, as insigni¬
ficant, many words which are to he found in all
languages, and some of which express what are
commonly regarded as the most important ob¬
jects of human knowledge. Of this number
are the words cause and effect; at least, in the
sense in which they are commonly understood
both by the vulgar and by philosophers. “ One
1 The incidental reference made, by way of illustration, in the following passage, to our instinctive conviction of the per¬
manency of the laws of Nature, encourages me to hope, that, among candid and intelligent inquirers, it is now received as
an acknowledged fact in the Theory of the Human Mind.
“ The anxiety men have in all ages shown to obtain a fixed standard of value, and that remarkable agreement of nations,
dissimilar in all other customs, in the use of one medium, on account of its superior fitness for that purpose, is itself a con¬
vincing proof how essential it is to our social interests. The notion of its permanency, although it be conventional and ar¬
bitrary, and liable, in reality, to many causes of variation, yet had gained so firm a hold on the minds of men, as to re¬
semble, in its effects on their conduct, that instinctive conviction of the permanency of the laws of nature which is the foimdation
of all our reasoning."—(A Letter to the Right Hon. R. Peel, M. P. for the University of Oxford, by one of his Constituents.
Second edition, p. 23.)
2 The difference between the two opinions amounts to nothing more than this, whether our expectation of the conti¬
nuance of the laws of nature results from a principle coeval with the first exercise of the senses; or whether it arises gra¬
dually from the accommodation of the order of our thoughts to the established order of physical events. “ Nature (as Mr
Hume himself observes) may certainly produce whatever can arise from habit; nay, habit is nothing but one of the prin¬
ciples of nature, and derives all its force from that origin.—(Treatise of Human Nature, Vol. I. p. 313.) Whatever ideas,
therefore, and whatever principles we are unavoidably led to acquire by the circumstances in which we are placed, and by
the exercise of those faculties which are essential to our preservation, are to be considered as parts of human nature, no less
than those which are implanted in the mind at its first formation. Are not the acquired perceptions of sight and of hear¬
ing as much parts of human nature as the original perceptions of external objects which we obtain by the use of the hand ?
The passage quoted from Mr Hume, in Note 2. p. 212, if attentively considered, will be found, when combined with
these remarks, to throw a strong and pleasing light on his latest views with respect to this part of his philosophy.
In denying that our expectation of the continuance of the laws of nature is founded on reasoning, as y^ll as in asserting
our ignorance of any necessary connections among physical events, Mr Hume had been completely anticipated by some of
his predecessors (See the references mentioned in the Note, p. 211.) I do not, however, think that, before his time, phi¬
losophers were at all aware of the alarming consequences which, on a superficial view, seem to follow from this part of his
system. Indeed, these consequences would never have been apprehended, had it not been supposed to form an essential
link in his argument against the commonly received notion of Causation.
PRELIMINARY DISSERTATIONS.
^14
event (says he) follows another; but we never
observe any tie between them. They seem con¬
joined, hut never connected. And as we can have
no idea of any thing which never appeared to
our outward sense or inward sentiment, the ne¬
cessary conclusion seems to be, that we have no
idea of connection or power at all; and that
these words are absolutely without any meaning,
when employed either in philosophical reasonings
or common life.”—(Hume’s Essays, Yol. II.
p. 79. Ed. of Lond. 1784.)
When this doctrine was first proposed by Mr
Hume, he appears to have been very strongly
impressed with its repugnance to the common
apprehensions of mankind. c< I am sensible (he
observes) that of all the paradoxes which I have
had, or shall hereafter have occasion to advance
in the course of this treatise, the present one is
the most violent.”—(Treatise of Human Nature,
Vol. I. p. 291.) It was probably owing to this
impression that he did not fully unfold in that
work all the consequences which, in his subse¬
quent publications, he deduced from the same
paradox; nor did he even apply it to invalidate
the argument which infers the existence of an
intelligent cause from the order of the universe.
There cannot, however, be a doubt that he was
aware, at this period of his life, of the conclu¬
sions to which it unavoidably leads, and which
are indeed too obvious to escape the notice of a
far less acute inquirer.
In a private letter of Mr Hume’s, to one of
his most intimate friends,1 some light is thrown
on the circumstances which first led his mind
into this train of sceptical speculation. As his
narrative has every appearance of the most per¬
fect truth and candour, and contains several
passages which I doubt not will be very gene¬
rally interesting to my readers, I shall give it a
place, together with some extracts from the cor¬
respondence to which it gave rise, in the Notes
at the end of this Dissertation. Every thing
connected with the origin and composition of a
work which has had so powerful an influence on
the direction which metaphysical pursuits have
since taken, both in Scotland2 and in Germany,
will be allowed to form an important article of
philosophical history; and this history I need
not offer any apology for choosing to communi¬
cate to the public rather in Mr Hume’s words
than in my own.5
From the reply to this letter by Mr Hume’s
very ingenious and accomplished correspondent,
we learn that he had drawn from Mr Hume’s
metaphysical discussions the only sound and
philosophical inference : that the lameness of
the proofs offered by Descartes and his succes¬
sors, of some fundamental truths universally
1 Sir Gilbert Elliot, Bart, grandfather of the present Earl of Minto. The originals of the letters to which I refer are in
Lord Minto’s possession.
2 A foreign writer, of great name (M. Frederick Schlegel), seems to think that the influence of Mr Hume’s Treatise of
Human Nature on the Philosophy of England has been still more extensive than I had conceived it to be. His opinion on
this point I transcribe as a sort of literary curiosity :
“ Since the time of Hume, nothing more has been attempted in England, than to erect all sorts of bulwarks against the
practical influence of his destructive scepticism; and to maintain, by various substitutes and aids, the pile of moral prin¬
ciple uncorrupted and entire. Not only with Adam Smith, but with all their late philosophers, national welfare is the ruling and
central principle of thought;—a principle excellent and praiseworthy in its due situation, but quite unfitted for being the centre and
orach of all knowledge and science." From the connection in which this last sentence stands with the context, would not one
imagine that the writer conceived the Wealth of Nations to be a new moral or metaphysical system, devised by Mr Smith, for
the purpose of counteracting Mr Hume’s scepticism ?
I have read this translation of Mr Schlegel’s lectures with much curiosity and interest, and flatter myself that we shall
soon have English versions of the works of Kant, and of other German authors, from the pens of their English disciples.
Little more, I am fully persuaded, is necessary, in this country, to bring down the philosophy of Germany to its proper
In treating of literary and historical subjects, Mr Schlegel seems to be more in his element, than when he ventures to
pronounce on philosophical questions. But even in cases of the former description, some of his dashing judgments on Eng¬
lish writers can be accounted for only by haste, caprice, or prejudice. “ The English themselves (we are told) are now
pretty well convinced, that Robertson is a careless, superficial, and blundering historian: although they study his works,
and are right in doing so, as models of pure composition, extremely deserving of attention during the present declining state
of English style •••••• • • With all the abundance of his Italian elegance, what is the overloaded and affected Roscoe
when compared with Gibbon . Coxe, although master of a good and classical style, resembles Robertson in no respect so
much as in the superncialness of his researches; and the statesman Fox has nothing in common with Hume but the bigotry
of his party zeal.” Such criticisms may perhaps be applauded by a German auditory, but in this country they can injure
the reputation of none but their author. J J
• See Note CCC.
DISSERTATION FIRST.
215
acknowledged by mankind, proceeded, not from
any defect in the evidence of these truths, but,
on the contrary, from their being self-evident,
and consequently unsusceptible of demonstra¬
tion. We learn, farther, that the same conclu¬
sion had been adopted, at this early period, by
another of Mr Hume’s friends, Mr Henry
Home, who, under the name of Lord Karnes,
was afterwards so well known in the learned
world. Those who are acquainted with the
subsequent publications of this distinguished
and most respectable author, will immediately
recognise, in the account here given of the im¬
pression left on his mind by Mr Hume’s scepti¬
cism, the rudiments of a peculiar logic, which
runs more or less through all his later works ;
and which, it must be acknowledged, he has, in
various instances, carried to an unphilosophical
extreme.1 2
The light in which Mr Hume’s scepticism
appears from these extracts to have struck his
friends, Sir Gilbert Elliot and Lord Karnes, was
very nearly the same with that in which it was
afterwards viewed by Reid, Oswald, and Beat-
tie, all of whom have manifestly aimed, with
greater or less precision, at the same logical
doctrine which I have just alluded to. This,
too, was the very ground on which Father Buf-
fier had (even before the publication of the
Treatise of Human Nature) made his 4 stand
against similar theories, built by his predeces¬
sors on the Cartesian principles. The coinci¬
dence between his train of thinking, and that
into which our Scottish metaphysicians soon
after fell, is so very remarkable, that it has been
considered by many as amounting to a proof
that the plan of their works was, in some mea¬
sure, suggested by his; but it is infinitely more
probable, that the argument which runs, in
common, through the speculations of all of them,
was the natural result of the state of metaphy¬
sical science when they engaged in their philo¬
sophical inquiries.8
The answer which Mr Hume made to this
argument, when it was first proposed to him in
the easy intercourse of private correspondence,
seems to me an object of so much curiosity, as
to justify me for bringing it under the eye of
my readers in immediate connection with the
foregoing details. Opinions thus communicat¬
ed in the confidence of friendly discussion, pos¬
sess a value which seldom belongs to proposi¬
tions hazarded in those public controversies
where the love of victory is apt to mingle, more
or less, in the most candid minds, with the love
of truth.
“ Your notion of correcting subtlety by sen¬
timent is certainly very just with regard to mo¬
rals, which depend upon sentiment: And in
politics and natural philosophy, whatever con¬
clusion is contrary to certain matters of fact,
must certainly be wrong, and there must some
error lie somewhere in the argument, whether
we be able to show it or not. But, in metaphy¬
sics or theology, I cannot see how either of these
plain and obvious standards of truth can have
place. Nothing there can correct bad reason¬
ing but good reasoning; and sophistry must be
opposed by syllogism.3 About seventy or eighty
years ago,4 * * I observe a principle like that which
you advance prevailed very much in France,
amongst some philosophers and beaux esprits.
1 I allude particularly to the unnecessary multiplication, in his philosophical arguments, of internal senses and of in¬
stinctive principles.
2 Voltaire, in his catalogue of the illustrious writers who adorned the reign of Louis XIV. is one of the very few French
authors who have spoken of Buffier with due respect: “ II y a dans ses traite's de mdtaphysique des morceaux que Locke
n’aurait pas desavoues, et c’est le seul jesuite qui ait mis une philosophie raisonnahle dans ses ouvrages.” Another French
philosopher, too, of a very different school, and certainly not disposed to overrate the talents of Buffier, has, in a work
published as lately as 1805, candidly acknowledged the lights which he might have derived from the labours of his prede¬
cessor, if he had been acquainted with them at an earlier period of his studies. Condillac, he also observes, might have
profited greatly by the same lights, if he had availed himself of their guidance, in his inquiries concerning the human un¬
derstanding. “ Du moins est il certain que pour ma part, je suis fort fachd de ne connoitre que depuis tres peu de temps ces
opinions du Pere Buffier; si je les avais vues plutot enoncees quelque part, elles m’auraient dpargne beaucoup de peines
et d’hdsitations.”—“ Je regrette beaucoup que Condillac, dans ses profondes et sagaces meditations sur I’intelligence hu-
maine, n’ait pas fait plus d’attention aux idees du Pere Buffier,” &c. &c—Eltmens d'Ideologic, par M. Destutt-Tracy,
Tom. III. pp. 136, 137. (See Elements of the Philosophy of the Human Mind, Vol. II. pp. 88, 89, 2d edit.)
3 May not sophistry be also opposed, by appealing to the fundamental laws of human belief; and, in some cases, by appeal-
mg to facts for which we have the evidence of our own consciousness ? The word sentiment does not express, with sufficient
precision, the test which Mr Hume’s correspondent had manifestly in view.
* This letter is dated 1751.
216
PRELIMINARY DISSERTATIONS.
The occasion of it was this : The famous M.
Nicole of the Port Royal, in his Perpetuite de la
Foi, pushed the Protestants very hard upon
the impossibility of the people’s reaching a con¬
viction of their religion by the way of private
judgment, which required so many disquisi¬
tions, reasonings, researches, erudition, impar¬
tiality, and penetration, as not one of a hundred,
even among men of education, is capable of. M.
Claude and the Protestants answered him, not
by solving his difficulties (which seems impos¬
sible), but by retorting them (which is very
easy.) They showed, that to reach the way of
authority which the Catholics insist on, as long
a train of acute reasoning, and as great erudi¬
tion was requisite, as would be sufficient for a
Protestant. We must first piwe all the truths
of natural religion, the foundation of morals,
the divine authority of the Scripture, the de¬
ference which it commands to the church, the
tradition of the church, &c. &c. The compari¬
son of these controversial writings begat an idea
in some, that it was neither by reasoning nor
authority we learn our religion, but by senti¬
ment ; and this was certainly a vei*y convenient
way, and what a philosopher would be very
well pleased to comply with, if he could dis¬
tinguish sentiment from education. But, to
all appearance, the sentiment of Stockholm,
Geneva, Rome, ancient and modern Athens, and
Memphis, have not the same characters; and
no thinking man can implicitly assent to any of
them, but from the general principle, that, as
the truth on these subjects is beyond human
capacity, and that, as for one’s own ease, he
must adopt some tenets, there is more satisfac¬
tion and com enience in holding to the cate¬
chism we have been first taught. Now, this I
have nothing to say against. I would only
observe, that such a conduct is founded on the
most universal and determined scepticism. For
more curiosity and research give a direct oppo¬
site turn from the same principles.”
On this careless effusion of Mr Hume’s pen,
it would be unpardonable to offer any critical
strictures. It cannot, however, be considered
as improper to hint, that there is a wide and
essential difference between those articles of
faith which formed the subjects of dispute be¬
tween Nicole and Claude, and those laws of be-
lief, of which it is the great object of the Trea¬
tise of Human Nature to undermine the autho¬
rity. The reply of Mr Hume, therefore, is
evasive, and although strongly marked with the
writer’s ingenuity, does not bear upon the point
in question.
As to the distinction alleged by Mr Hume
between the criteria of truth in natural philo¬
sophy and in metaphysics, I trust it will now be
pretty generally granted, that however well
founded it may be when confined to the meta¬
physics of the schoolmen, it will by no means
hold when extended to the inductive philosophy
of the human mind. In this last science, no
less than in natural philosophy, Mr Hume’s
logical maxim may be laid down as a funda¬
mental principle, that “ whatever conclusion is
contrary to toiatter of fact must be wrong, and
there must some error lie somewhere in the ar¬
gument, whether we be able to show it or not.”
It is a remarkable circumstance in the history
of Mr Hume’s literary life, and a proof of the
sincerity with which he was then engaged in the
search of truth, that, previous to the publication
of his Treatise of Human Nature, he discovered
a stroiag anxiety to submit it to the examination
of the celebrated Hr Butler, author of the Ana-
logy of Religion, Natural and Revealed, to the
Constitution and Course of Nature. For this pur¬
pose he applied to Mr Henry Home, between
whom and Hr Butler some friendly letters ap¬
pear to have passed before this period. “ Your
thoughts and mine (says Mr Hume to his cor¬
respondent) agree with respect to Hr Butler,
and I would be glad to be introduced to him.
I am at present castrating my work, that is, cut¬
ting off its nobler parts; that is, endeavouring
it shall give as little offence as possible, before
which I could not pretend to put it into the doc¬
tor’s hands.”1 In another letter, he acknow¬
ledges Mr Home’s kindness in recommending
him to Hr Butler’s notice. “ I shall not trouble
1 For the rest of the letter, see Memoirs of the Life and Writings of Lord Karnes, by Lord Woodhouselee, Vol. 1. p. 84,
et seq.
DISSERTATION FIRST.
217
you with any formal compliments or thanks,
which would be but an ill return for the kind¬
ness you have done me in writing in my behalf,
to one you are so little acquainted with as Dr
Butler; and, I am afraid, stretching the truth
in favour of a friend. I have called on the doc¬
tor, with a design of delivering your letter, but
find he is at present in the country. I am a little
anxious to have the doctor’s opinion. My own
I dare not trust to; both because it concerns
myself, and because it is so variable, that I
know not how to fix it. Sometimes it elevates
me above the clouds ; at other times it depresses
me with doubts and fears; so that, whatever be
my success, I cannot be entirely disappointed.”
Whether Mr Hume ever enjoyed the satisfac¬
tion of a personal interview with Dr Butler, I
have not heard. From a letter of his to Mr
Home, dated London, 1739, we learn that if
any intercourse took place between them, it
must have been after the publication of the
Treatise of Human Nature. “ I have sent the
Bishop of Bristol a copy; but could not wait
upon him with your letter after he had arrived
at that dignity. At least, I thought it would be
to no purpose after I began the printing.”1 In
a subsequent letter to the same correspondent,
written in 1742, he expresses his satisfaction at
the favourable opinion which he understood Dr
Butler had formed of his volume of Essays, then
recently published, and augurs well from this
circumstance of the success of his book. “ I am
told that Dr Butler has everywhere recommend¬
ed them, so that I hope they will have some
success.”2 3 *
These particulars, trifling as they may ap¬
pear to some, seemed to me, for more reasons
than one, not unworthy of notice in this sketch.
Independently of the pleasing record they afford
of the mutual respect entertained by the eminent
men to whom they relate, for each other’s philo¬
sophical talents, they have a closer connection
with the history of metaphysical and moral in¬
quiry in this island, than might be suspected by
those who have not a very intimate acquaintance
with the writings of both. Dr Butler was, I
think, the first of Mr Locke’s successors who
clearly perceived the dangerous consequences
likely to be deduced from his account of the ori¬
gin of our ideas literally interpreted; and al¬
though he has touched on this subject but once,
and that with his usual brevity, he has yet said
enough to show, that his opinion with respect to
it was the same with that formerly contended
for by Cudworth, in opposition to Gassendi and
Hobbes, and which has since been revived in
different forms by the ablest of Mr Hume’s an¬
tagonists.5 With these views, it may be rea¬
sonably supposed, that he was not displeased to
see the consequences of Locke’s doctrine so very
logically and forcibly pushed to their utmost
limits, as the most effectual means of rousing
the attention of the learned to a re-examination
of this fundamental principle. That he was
perfectly aware, before the publication of Mr
Hume’s work, of the encouragement given to
scepticism by the logical maxims then in vogue,
is evident from the concluding paragraph of his
short Essay on Personal Identity. Had it been
published a few years later, nobody would have
doubted, that it had been directly pointed at the
general strain and spirit of Mr Hume’s philo¬
sophy.
“ But though we are thus certain, that we
are the same agents or living beings now, which
we were as far back as our remembrance reaches:
yet it is asked, Whether we may not possibly be
deceived in it ? And this question may be ask¬
ed at the end of any demonstration whatever,
because it is a question concerning the truth of
perception by memory. And he who can doubt,
whether perception by memory can in this case
be depended on, may doubt also whether per¬
ception by deduction and reasoning, which also
includes memory, or indeed whether intuitive
perception can. Here then we can go no far-
1 Memoirs of the Li fe and Writings o f Lord Kames, "Vol. I. p. 92.
2 Ibid. p. 404. The Essays here referred to were the first part of the Essays Moral, Political, and Literary, published
in 1742. The elegant author of these Memoirs has inadvertently confounded this volume with the second part of that
work, containing the Political Discourses (properly so called), which did not appear till ten years afterwards.
3 See the short Essay on Personal Identity, at the end of Butler’s Analogy ; and compare the second paragraph with the
remarks on this part of Locke’s Essay by Dr Price. (Review of the Principal Questions and Difficulties relating to Morals, pp.
49, 50. 3d ed. Lond. 1787-)
D1SS. T. PART II. 2 E
218
PRELIMINARY DISSERTATIONS.
ther. For it is ridiculous to attempt to prove
the truth of those perceptions whose truth we
can no otherwise prove than by other percep¬
tions of exactly the same kind with them, and
which there is just the same ground to suspect;
or to attempt to prove the truth of our facul¬
ties, which can no otherwise be proved, than by
the use or means of those very suspected facul¬
ties themselves.”1
It is, however, less as a speculative meta¬
physician, than as a philosophical inquirer into
the principles of morals, that I have been in¬
duced to associate the name of Butler with that
of Hume. And, on this account, it may be
thought that it would have been better to delay
what I have now said of him till I come to trace
the progress of Ethical Science during the eigh¬
teenth century. To myself it seemed more na¬
tural and interesting to connect this historical
or rather biographical digression, with the ear¬
liest notice I was to take of Mr Hume as an
author. The numerous and important hints on
metaphysical questions which are scattered over
Butler’s works, are sufficient of themselves to
account for the space I have allotted to him
among Locke’s successors; if, indeed, any apo¬
logy for this be necessary, after what I have al¬
ready mentioned, of Mr Hume’s ambition to
submit to his judgment the first fruits of his
metaphysical studies.
The remarks hitherto made on the Treatise of
Human Nature are confined entirely to the first
volume. The speculations contained in the two
others, on Morals, on the Nature and Founda¬
tions of Government, and on some other topics
connected with political philosophy, will fall
under our review afterwards.
Dr Reid’s Inquiry into the Human Mind (pub¬
lished in 1764) was the first direct attack which
appeared in Scotland upon the sceptical conclu¬
sions of Mr Hume’s philosophy. For my own
opinion of this work I must refer to one of my
former publications.2 It is enough to remark
here, that its great object is to refute the Ideal
Theory which was then in complete possession
of the schools, and upon which Dr Reid con¬
ceived that the whole of Mr Hume’s philosophy,
as well as the whole of Berkeley’s reasonings
against the existence of matter, was founded.
According to this theory we are taught, that
“ nothing is perceived but what is in the mind
which perceives it; that we do not really per¬
ceive things that are external, but only cer¬
tain images and pictures of them imprinted
upon the mind, which are called impressions and
ideas.”—cc This doctrine (says Dr Reid on ano¬
ther occasion) I once believed so firmly, as to
embrace the whole of Berkeley’s system along
with it; till finding other consequences to fol¬
low from it, which gave me more uneasiness than
the want of a material world, it came into my
mind, more than forty years ago, to put the
question, What evidence have I for this doc¬
trine, that all the objects of my knowledge are
ideas in my own mind ? From that time to
the present, I have been candidly and impartial¬
ly, as I think, seeking for the evidence of this
principle; but can find none, excepting the
authority of philosophers.”
On the refutation of the ideal theory, con¬
tained in this and his other works, Dr Reid
himself was disposed to rest his chief merit as
an author. “ The merit (says he in a letter
to Dr James Gregory) of what you are pleased
to call my Philosophy, lies, I think, chiefly in
having called in question the common theory of
ideas or images of things in the mind being the
only objects of thought; a theory founded on
natural prejudices, and so universally received as
to be interwoven with the structure of lan¬
guage. Yet were I to give you a detail of what
led me to call in question this theory, after I
had long held it as self-evident and unquestion¬
able, you would think, as I do, that there was
much of chance in the matter. The discovery
was the birth of time, not of genius; and Berke-
1 I must not, however, be understood as giving unqualified praise to this Essay. It is by no means free from the old
scholastic jargon, and contains some reasoning which, I may confidently assert, the author would not have employed, had it
been written fifty years later. Whoever takes the trouble to read the paragraph beginning with these words, “ Thirdly,
Every person is conscious,” &c. will immediately perceive the truth of this remark. I mention it as a proof of the change
to the better, which has taken place since Butler’s time, in the mode of thinking and writing on Metaphysical questions.
* See Biographical Memoirs, Edin. 1811.
DISSERTATION FIRST.
219
ley and Hume did more to bring it to light than
the man that hit upon it. I think there is hard¬
ly any thing that can be called mine in the phi¬
losophy of the mind, which does not follow with
ease from the detection of this prejudice.
“ I must, therefore, beg of you, most earnest¬
ly, to make no contrast in my favour to the dis¬
paragement of my predecessors in the same pur¬
suits. I can truly say of them, and shall al¬
ways avow, what you are pleased to say of me,
that, hut for the assistance I have received from
their writings, I never could have wrote or
thought what I have done.”1 2
When I reflect on the stress thus laid by Hr
Reid on this part of his writings, and his fre¬
quent recurrence to the same argument when¬
ever his subject affords him an opportunity of
forcing it upon the attention of his readers, I
cannot help expressing my wonder, that Kant
and other German philosophers, who appear to
have so carefully studied those passages in Reid,
which relate to Hume’s Theory of Causation,
should have overlooked entirely what he him¬
self considered as the most original and im¬
portant of all his discussions; more especially
as the conclusion to which it leads has been
long admitted, by the best judges in this island,
as one of the few propositions in metaphysical
science completely established beyond the reach
of controversy. Even those who affect to speak
the most lightly of Hr Reid’s contributions to
the philosophy of the human mind, have found
nothing to object to his reasonings against the
ideal theory, but that the absurdities involved
in it are too glaring to require a serious ex¬
amination.® Had these reasonings been consi¬
dered in the same light in Germany, it is quite
impossible that the analogical language of Leib¬
nitz, in which he speaks of the soul as a living
mirror of the universe^ could have been again re¬
vived ; a mode of speaking liable to every ob¬
jection which Reid has urged against the ideal
theory. Such, however, it would appear, is the
fact. The word Representation (VorstellungJ is
1 An ingenious and profound writer, who, though intimately connected with Mr Hume in habits of friendship, was not
blind to the vulnerable parts of his Metaphysical System, has bestowed, in the latest of his publications, the following en¬
comium on Dr Reid’s Philosophical Works.
“ The author of an Inquiry into the Mind, and of subsequent Essays on the Intellectual and Active Powers of Man, has great
merit in the effect to which he has pursued this history. But, considering the point at which the science stood when he
began his inquiries, he has, perhaps, no less merit in having removed the mist of hypothesis and metaphor, with which the
subject was enveloped; and, in having taught us to state the facts of which we are conscious, not in figurative language,
but in the terms which are proper to the subject. In this it will be our advantage to follow him ; the more that, in former
theories, so much attention had been paid to the introduction of ideas or images as the elements of knowledge, that the be¬
lief of any external existence or prototype has been left to be inferred from the mere idea or image; and this inference,
indeed, is so little founded, that many who have come to examine its evidence have thought themselves warranted to deny
it altogether. And hence the scepticism of ingenious men, who, not seeing a proper access to knowledge through the me¬
dium of ideas, without considering whether the road they had been directed to take was the true or a false one, denied the
possibility of arriving at the end.”—(Principles of Moral and Political Science, by Dr Adam Ferguson, Vol. I. pp. 7b, 76.)
The work from which this passage is taken contains various important observations connected with the Philosophy of the
Human Mind; but as the taste of the author led him much more strongly to moral and political speculations, than to re¬
searches concerning the intellectual powers of man, I have thought it right to reserve any remarks which I have to offer
on his philosophical merits for the last part of this Discourse.
2 I allude here more particularly to Dr Priestley, who, in a work published in 177b alleged, that when philosophers
called ideas the images of external things, they are only to be understood as speaking figuratively; and that Dr Reid has
gravely argued against this metaphorical language, as if it were meant to convey a theory of perception. The same remark
has been repeated over and over since Priestley’s time, by various writers. I have nothing to add in reply to it to what I
long ago stated in my Philosophical Essays (see Note H. at the end of that work), but the following short quotation
from Mr Hume:—
“ It seems evident, that, when men follow this blind and powerful instinct of nature, they always suppose the very
images, presented by the senses, to be the external objects, and never entertain any suspicion, that the one are nothing but
representations of the other. * * * * But this universal and primary opinion of all men is soon destroyed by the slightest phi¬
losophy, which teaches us, that nothing can ever be present to the mind but an image or perception, and that the senses are
only the inlets through which these images are conveyed, without being able to produce any immediate intercourse between
the mind and the object. The table which we see seems to diminish as we remove farther from it; but the real table,
which exists independent of us, suffers no alteration. It was, therefore, nothing but its image which was present to the
mind. These are the obvious dictates of reason.”—(Essay on the Academical Philosophy.)
Is not this analogical theory of perception the principle on which the whole of Berkeley’s reasonings against the existence
of the material world, and of Hume’s scepticism on the same subject, are founded ?
The same analogy still continues to be sanctioned by some English philosophers of no small note. Long after the publi¬
cation of Dr Reid’s Inquiry, Mr Horne Tooke quoted with approbation the following words of J. C. Scaliger : “ Sicut in
speculo ea quse videntur non sunt, sed eorum species ; ita quae intelligimus, ea sunt re ipsa extra nos, eorumque species in
nobis. Est enim quasi rerum speculum intellectus noster; cui, nisi per sensum represententur res,
nihil scit ipse.”—(J. C. Scaliqer, de Causis, L. I., cap. Ixvi.) Dfrmwnw of Parley, Vol. I. p. 35, 2d. Edition.
220
PRELIMINARY DISSERTATIONS,
now the German substitute for Idea ; nay, one
of the most able works which Germany has pro¬
duced since the commencement of its new phi¬
losophical era, is entitled Nova Theoria Facul-
tatis Representativce Humana;. In the same work,
the author has prefixed, as a motto to the second
book, in which he treats of <c the Representative
Faculty in general,” the following sentence from
Locke, which he seems to have thought himself
entitled to assume as a first principle : “ Since
the mind, in all its thoughts and reasonings,
hath no other immediate object but its own ideas
(representationsJ, which it alone does or can
contemplate, it is evident that our knowledge is
only conversant about them.”—(Locke’s Essay,
B. IV. ch. 1.) In a country where this meta¬
physical jargon still passes current among wri¬
ters of eminence, it is vain to expect that any
solid progress can be made in the inductive phi¬
losophy of the human mind. A similar remark
may be extended to another country, where
the title of Ideologie (a word which takes for
granted the truth of the hypothesis which it
was Reid’s great aim to explode) has been lately
given to the very science in which the theory
of Ideas has been so clearly shown to have been,
in all ages, the most fruitful source of error and
absurdity.1
Of the other works by Scottish metaphysi¬
cians, which appeared soon after the Inquiry into
the Human Mind, I have not left myself room
to speak. I know of none of them from which
something important may not be learned; while
several of them (particularly those of Dr Camp¬
bell) have struck out many new and interesting
views. To one encomium all of them are well
entitled, that of aiming steadily at the advance¬
ment of useful knowledge and of human happi¬
ness. But the principles on which they have
proceeded have so close an affinity to those of
Dr Reid, that I could not, without repeating
what I have already said, enter into any ex¬
planation concerning their characteristical doc¬
trines.
On comparing the opposition which Mr
Hume’s scepticism encountered from his own
countrymen, with the account formerly given
of the attempts of some German philosophers to
refute his Theory of Causation, it is impossible
not to be struck with the coincidence between
the leading views of his most eminent antago¬
nists. This coincidence one would have been
disposed to consider as purely accidental, if
Kant, by his petulant sneers at Reid, Beattie,
and Oswald, had not expressly acknowledged,
that he was not unacquainted with their writ¬
ings. As for the great discovery, which he
seems to claim as his own,—that the ideas of
Cause and Effect, as well as many others, are
derived from the pure understanding without any
aid from experience, it is nothing more than a
repetition, in very nearly the same terms, of
what was advanced a century before by Cud-
worth, in reply to Hobbes and Gassendi; and
borrowed avowedly by Cudworth from the rea¬
sonings of Socrates, as reported by Plato, in
answer to the scepticism of Protagoras. This
recurrence, under different forms, of the same
metaphysical controversies, which so often sur¬
prises and mortifies us in the history of litera¬
ture^ is an evil which will probably always con¬
tinue, more or less, even in the most prosperous
state of philosophy. But it affords no objection
to the utility of metaphysical pursuits. While
the sceptics keep the field, it must not be aban¬
doned by the friends of sounder principles; nor
ought they to be discouraged from their un¬
grateful task, by the reflection, that they have
probably been anticipated, in everything they
have to say, by more than one of their predeces¬
sors. If any thing is likely to check this perio¬
dical return of a mischief so unpropitious to the
progress of useful knowledge, it seems to be
the general diffusion of that historical informa¬
tion concerning the literature and science of
former times, of which it is the aim of these
Preliminary Dissertations to present an outline.
Should it fail in preventing the occasional re-
1 In censuring these metaphorical terms, lam far from supposing that the learned writers who have employed them
have been all misled by the theoretical opinions involved in their language. Reinhold has been more particufarly careM
in guarding against such a misapprehension. But it cannot, I think, be doubted that the prevalence of such a phraseologv
must have a tendency to divert the attention from a just view of the mental phenomena and to infuse into the mind^f
the young inquirer very false conceptions of the manner in which these phenomena ought to be studied.
DISSERTATION FIRST.
221
vival of obsolete paradoxes, it will, at least, di¬
minish the wonder and admiration with which
they are apt to he regarded by the multitude.
And here I cannot refrain from remarking
the injustice with which the advocates for truth
are apt to be treated; and by none more re¬
markably than by that class of writers who pro¬
fess the greatest zeal for its triumph. The im¬
portance of their labours is discredited by those
who are the loudest in their declamations and
invectives against the licentious philosophy of
the present age; insomuch that a careless ob¬
server would be inclined to imagine (if I may
borrow Mr Hume’s words on another occasion),
that the battle was fought “ not by the men at
arms, who manage the pike and the sword; but
by the trumpeters, drummers, and musicians,
of the army.”
These observations may serve, at the same
time, to account for the slow and (according to
some persons) imperceptible advances of the
philosophy of the human mind, since the publi¬
cation of Locke’s Essay. With those who still
attach themselves to that author, as an infallible
guide in metaphysics, it is in vain to argue;
but I would willingly appeal to any of Locke’s
rational and discriminating admirers, whether
much has not been done by his successors, and,
among others, by members of our northern uni¬
versities, towards the illustration and correction
of such of his principles as have furnished, both
to English and French sceptics, the foundation
of their theories.1 If this be granted, the way
has, at least, been cleared and prepared for the
labours of our posterity; and neither the cavils
of the sceptic, nor the refutation of them by the
sounder logician, can be pronounced to be use¬
less to mankind. Nothing can be juster or more
liberal than the following reflection of Reid :
“ I conceive the sceptical writers to be a set of
men, whose business it is to pick holes in the
fabric of knowledge wherever it is weak and
faulty ; and when those places are properly re¬
paired, the whole building becomes more firm
and solid than it was formerly.”—(Inquiry into
the Human Mind. Dedication.)
There is, indeed, one point of view, in which
it must be owned that Mr Hume’s Treatise has
had an unfavourable effect (and more especially
in Scotland) on the progress of Metaphysical
Science. Had it not been for the zeal of some
of his countrymen to oppose the sceptical con¬
clusions, which they conceived it to be his aim
to establish, much of that ingenuity which has
been wasted in the refutation of his sophistry
(or, to speak more correctly, in combating the
mistaken principles on which he proceeded)
would, in all probability, have been directed to
speculations more immediately applicable to the
business of life, or more agreeable to the taste
of the present age. What might not have been
expected from Mr Hume himself, had his power¬
ful and accomplished mind been more frequent¬
ly turned to the study of some parts of our na¬
ture (of those, for example, which are connected
with the principles of criticism), in examining
which, the sceptical bias of his disposition would
have had fewer opportunities of leading him
astray ! In some fragments of this sort, which
enliven and adorn his collection of Essays, one
is at a loss whether more to admire the subtlety
of his genius, or the solidity and good sense of
his critical judgments.
Nor have these elegant applications of meta¬
physical pursuits been altogether overlooked by
Mr Hume’s antagonists. The active and ad¬
venturous spirit of Lord Kames, here, as in
many other instances, led the way to his coun¬
trymen ; and, due allowances being made for
the novelty and magnitude of his undertaking,
with a success far greater than could have been
reasonably anticipated. The Elements of Criti¬
cism, considered as the first systematical attempt
to investigate the metaphysical principles of the
1 According to Dr Priestley, the labours of these commentators on Locke have done more harm than good. “ I think
Mr Locke has been hasty in concluding that there is some other source of our ideas besides the external senses ; but the rest
of his system appears to me and others to be the corner stone of all just and rational knowledge of ourselves.”
“ This solid foundation, however, has lately been attempted to be overturned by a set of pretended philosophers,^ of
whom the most conspicuous and assuming is Dr Iteid, Professor of Moral Philosophy in the University of Glasgow.’ —
(Exam, of Reid, Beattie, and Oswald, p. 5.)—As to Mr Hume, Dr Priestley says, “ In my opinion, he has been very ably
answered, again and again, upon more solid principles than those of this new common sense ; and I beg leave to refer to the
two first volumes of my Institutes of Natural and Revealed Religion."—(Examination of Reid, 8[C. Preface, p. xxvii.
222
PRELIMINARY DISSERTATIONS.
fine arts, possesses, in spite of its numerous de¬
fects both in point of taste and of philosophy,
infinite merits, and will ever be regarded as a
literary wonder by those who know how small
a portion of his time it was possible for the au¬
thor to allot to the composition of it, amidst the
imperious and multifarious duties of a most ac¬
tive and useful life. Campbell and Gerard, with
a sounder philosophy, and Beattie, with a much
more lively relish for the Sublime and the Beau¬
tiful, followed afterwards in the same path; and
have all contributed to create and to diffuse over
this island a taste for a higher and more en¬
lightened species of criticism than was known
to our forefathers. Among the many advan¬
tageous results with which this study has been
already attended, the most important, undoubt¬
edly, is the new and pleasing avenue which it
has opened to an analysis of the laws which re¬
gulate the intellectual phenomena; and the in¬
terest which it has thus lent, in the estimation
of men of the world, to inquiries which, not
many years before, were seldom heard of, but
within the walls of an university.
Dr Reid’s two volumes of Essays on the Intel¬
lectual and on the Active Powers of Man (the for¬
mer of which appeared in 1785, and the latter
in 1788) are the latest philosophical publications
from Scotland of which I shall at present take
notice. They are less highly finished, both in
matter and in form, than his Inquiry into the
Human Mind. They contain also some repeti¬
tions, to which, I am afraid, I must add a few
trifling inconsistencies of expression, for which
the advanced age of the author, who was then
approaching to fourscore, claims every indul¬
gence from a candid reader. Perhaps, too, it
may be questioned, whether, in one or two in¬
stances, his zeal for an important conclusion has
not led him to avail himself of some dubious
reasonings, which might have been omitted with¬
out any prejudice to his general argument.
“ The value of these volumes, however (as I
have elsewhere remarked), is inestimable to fu¬
ture adventurers in the same arduous inquiries,
not only in consequence of the aids they furnish
as a rough draught of the field to be examined,
but by the example they exhibit of a method of
investigation on such subjects, hitherto very im¬
perfectly understood, even by those philosophers
who call themselves the disciples of Locke. It
is by the logical rigour of this method, so syste¬
matically pursued in all his researches, still
more than by the importance of his particular
conclusions, that he stands so conspicuously dis¬
tinguished among those who have hitherto pro¬
secuted analytically the study of man.” 1
His acquaintance with the metaphysical doc¬
trines of his predecessors does not appear to have
been very extensive; with those of his own con¬
temporaries it was remarkably deficient. I do
not recollect that he has anywhere mentioned
the names either of Condillac or of D’Alembert.
It is impossible not to regret this, not only as it
has deprived us of his critical judgments on some
celebrated theories, but as it has prevented him
from enlivening his works with that variety of
historical discussion so peculiarly agreeable in
these abstract researches.
On the other hand, Dr Reid’s limited range
of metaphysical reading, by forcing him to draw
the materials of his philosophical speculations
almost entirely from his own reflections, has
given to his style, both of thinking and of writ¬
ing, a characteristical unity and simplicity sel¬
dom to be met with in so voluminous an author.
He sometimes, indeed, repeats, with an air of
originality, what had been previously said by
his predecessors; but on these, as on all other
occasions, he has at least the merit of thinking
for himself, and of sanctioning, by the weight
of his unbiassed judgment, the conclusions
which he adopts. It is this uniformity of thought
and design, which, according to Dr Butler, is
the best test of an author’s sincerity; and I am
apt to regard it also, in these abstruse disquisi¬
tions, as one of the surest marks of liberal and un¬
fettered inquiry.
In comparing Dr Reid’s publications at differ¬
ent periods of his life, it is interesting to observe
his growing partiality for the aphoristical style.
Some of his Essays on the Intellectual and Active
Biographical Account of Jleid.
DISSERTATION FIRST.
223
Powers of Man are little more than a series of
detached paragraphs, consisting of leading
thoughts, of which the reader is left to trace
the connection by his own sagacity. To this
aphoristical style it is not improbable that he
was partly led by the indolence incident to ad¬
vanced years, as it relieved him from what
Boileau justly considered as the most difficult
task of an author, the skilful management of
transitions.1 In consequence of this want of
continuity in his compositions, a good deal of
popular effect is unavoidably lost; but, on the
other hand, to the few who have a taste for such
inquiries, and who value hooks chiefly as they
furnish exercise to their own thoughts (a class
of readers who are alone competent to pronounce
a judgment on metaphysical questions), there is
a peculiar charm in a mode of writing, so ad¬
mirably calculated to give relief to the author’s
ideas, and to awaken, at every sentence, the re¬
flections of his readers.
When I review what I have now written on the
history of Metaphysics in Scotland, since the
publication of Mr Hume’s Treatise, and at the
same time recollect the laurels which, during the
same period, have been won by Scottish authors,
in every other department of literature and of
science, I must acknowledge that, instead of
being mortified at the slender amount of their
contributions to the philosophy of the human
mind, I am more disposed to wonder at their
successful perseverance in cultivating a field of
study, where the approbation of a few enlight¬
ened and candid judges is the only reward to
which their ambition could aspire. Small as
their progress may hitherto have been, it will at
least not suffer by a comparison with what has
been accomplished by their contemporaries in
any other part of Europe.
It may not be useless to add in this place, that,
if little has as yet been done, the more ample is
the field left for the industry of our successors.
The compilation of a Manual of Rational Logic,
adapted to the present state of science and of
society in Europe, is a desideratum which, it is
to be hoped, will at no distant period be sup¬
plied. It is a work, certainly, of which the exe¬
cution has been greatly facilitated by the philo¬
sophical labours of the last century. The varie¬
ties of intellectual character among men present
another very interesting object of study, which,
considering its practical utility, has not yet ex¬
cited, so much as might have been expected,
the curiosity of our countrymen. Much, too, is
still wanting to complete the theory of evidence.
Campbell has touched upon it with his usual
acuteness, hut he has attempted nothing more
than an illustration of a very few general prin¬
ciples. Nor has he turned his attention to the
various illusions of the imagination, and of the
passions, by which the judgment is liable to he
warped in the estimates it forms of moral evi¬
dence in the common affairs of life. This is a
most important inquiry, considering how often
the lives and fortunes of men are subjected to
the decisions of illiterate persons concerning cir¬
cumstantial proofs; and how much the success
or failure of every individual in the conduct of
his private concerns turns on the sagacity or
rashness with which he anticipates future con¬
tingencies. Since the time when Campbell wrote,
an attempt has been made by Condorcet2 and
some other French writers, to apply a mathema¬
tical calculus to moral and political truths; but
though much metaphysical ingenuity, as well as
mathematical skill, have been displayed in carry¬
ing it into execution, it has not yet led to any
useful practical results. Perhaps it may even
be questioned, whether, in investigating truths
of this sort, the intellectual powers can derive
much aid from the employment of such an organ.
To define accurately and distinctly the limits of
its legitimate province, still remains a desidera¬
tum in this abstruse part of logic.
Nearly connected with this subject are the
metaphysical principles assumed in the mathe¬
matical Calculation of Probabilities; in deliver¬
ing which principles, some foreign mathemati¬
cians, with the illustrious La Place at their
head, have blended, with many unquestionable
1 Boileau is said, by the younger Racine, to have made this remark in speaking of La Bruyere: “ II disoit que La
Bruyere s’etoit epargnd le plus difficile d'un ouvrage en s’epargnant les transitions.”—Mtmoire sur la Vie de Jean Racine.)
* Essai sur VApplication de VAnalyse a la Probability des Decisions rendues a lapluralite des Voix.
224
PRELIMINARY DISSERTATIONS.
and highly interesting' conclusions, various moral
paralogisms of the most pernicious tendency.
A critical examination of these paralogisms,
which are apt to escape the attention of the
reader amid the variety of original and luminous
discussions with which they are surrounded,
would, in my humble apprehension, be one of
the most essential services which could at pre¬
sent be rendered to true philosophy. In the
mind of La Place, their origin may be fairly
traced to an ambition, not altogether unnatural
in so transcendant a genius, to extend the empire
of his favourite science over the moral as well
as the material world.1 2 I have mentioned but a
few out of the innumerable topics which crowd
upon me as fit objects of inquiry for the rising
generation.® Nor have I been guided in my
selection of these by any other consideration,
than their peculiar adaptation to the actual cir¬
cumstances of the philosophical world.
Should such men as Hume, Smith, and Reid
again arise, their curiosity would, in all proba¬
bility, be turned to some applications of meta¬
physical principles of a more popular and prac¬
tical nature than those which chiefly engaged
their curiosity. At the same time, let us not
forget what a step they made beyond the scho¬
lastic philosophy of the preceding age; and
how necessary this step was as a preliminary
to other researches bearing more directly and
palpably on human affairs.
The most popular objection hitherto made to
our Scottish metaphysicians is, that, in treating
of human nature, they have overlooked altoge¬
ther the corporeal part of our frame. From the
contempt which they have uniformly expressed
for all physiological theories concerning the in¬
tellectual phenomena, it has been concluded,
that they were disposed to consider the human
mind as altogether independent of the influence
of physical causes. Mr Belsham has carried
this charge so far, as to sneer at Dr Reid’s in¬
consistency for having somewhere acknowledg¬
ed, <c in opposition to his systematical principles,
that a certain constitution or state of the brain is
necessary to memory.” In reply to this charge,
it may be confidently asserted, that no set of
philosophers, since the time of Lord Bacon, have
entertained juster views on this subject than
the school to which Dr Reid belonged. In proof
of this, I need only appeal to the Lectures on the
Duties and Qualifications of a Physician^ by the late
learned and ingenious Dr John Gregory. Among
the different articles connected with the natural
history of the human species, which he has there
recommended to the examination of the medical
student, he lays particular stress on “ the laws
of union between the mind and body, and the
mutual influence they have upon one another.”
“ This (he observes) is one of the most impor¬
tant inquiries that ever engaged the attention
of mankind, and almost equally necessary in
the sciences of morals and of medicine.” It
must be remarked, however, that it is only the
laws which regulate the union between mind
and body (the same class of facts which Bacon
called the doctrina de feedere), which are here
pointed out as proper objects of philosophical
curiosity; for as to any hypothesis concerning
the manner in which the union is carried on,
this most sagacious writer was well aware, that
they are not more unfavourable to the improve¬
ment of logic and of ethics, than to a skilful
and judicious exercise of the healing art.
I may perhaps form too high an estimate of
the progress of knowledge during the last fifty
years; but I think I can perceive, within the
period of my own recollection, not only a
change to the better in the Philosophy of the
Human Mind, but in the speculations of me¬
dical inquirers. Physiological theories concern¬
ing the functions of the nerves in producing
the intellectual phenomena have pretty gene¬
rally fallen into contempt: and, on the other
hand, a large accession has been made to our
stock of well authenticated facts, both with re-
1 The paralogisms to which I allude did not fall within the scope of the admirable criticism on this work in the Edin¬
burgh Review.
2 Among these, the most prominent is the Natural or Theoretical History of Language (including under this title writ¬
ten as well as oral language), a subject which will probably continue to furnish new pi'oblems to human ingenuity, in the
most improved state of human knowledge. It is not surprising that an art which lays the foundation of all the others, and
which is so intimately connected with the exercise of reason itself, should leave behind it such faint and obscure traces of
its origin and infancy.
DISSERTATION FIRST.
225
spect to the influence of body on mind, and of
mind upon body. As examples of this, it is
sufficient to mention the experimental inquiries
instituted, in consequence of the pretended cures
effected by means of Animal Magnetism and of
Tractors; to which may be added, the philo¬
sophical spirit evinced in some late publications
on Insanity.
Another objection, not so entirely ground¬
less, which has been made to the same school,
is, that their mode of philosophising has led to
an unnecessary multiplication of our internal
senses and instinctive determinations. For this
error, I have elsewhere attempted to account
and to apologise.1 * 3 * On the present occasion I
shall only remark, that it is at least a safer er¬
ror than the opposite extreme, so fashionable of
late among our southern neighbours, of endea¬
vouring to explain away, without any excep¬
tion, all our instinctive principles, both specula¬
tive and practical. A literal interpretation of
Locke’s comparison of the infant mind to a
sheet of white paper (a comparison which, if I
am rightly informed, has not yet wholly lost its
credit in all our universities), naturally predis¬
posed his followers to embrace this theory, and
enabled them to shelter it from a free examina¬
tion, under the sanction of his supposed autho¬
rity. Dr Paley himself, in his earliest philo¬
sophical publication, yielded so far to the preju¬
dices in which he had been educated, as to dis¬
pute the existence of the moral faculty;* al¬
though, in his more advanced years, he amply
atoned for this error of his youth, by the inge¬
nuity and acuteness with which he combated
the reasonings employed by some of his con¬
temporaries, to invalidate the proofs afforded
by the phenomena of instinct, of the existence of
a designing and provident cause. In this part
of his work, he has plainly in his eye the Zoo-
nomia of Dr Darwin,8 where the same prin¬
ciples, of which Paley and others had availed
themselves to disprove the existence of instinct
and instinctive propensities in man, are eagerly
laid hold of to disprove the existence of instinct
in the brutes. Without such an extension of
the argument, it was clearly perceived by Dar¬
win, that sufficient evidences of the existence of
a Designing Cause would be afforded by the
phenomena of the lower animals; and, accord¬
ingly, he has employed much ingenuity to show,
that all these phenomena may be accounted for
by experience, or by the influence of pleasurable
or painful sensations, operating at the moment
on the animal frame.
In opposition to this theory, it is maintained
by Paley, that it is by instinct, that is, accord¬
ing to his own definition, “ by a propensity
1 Biographical Memoirs, p. 472.
1 After relating, in the words of Valerius Maximus, the noted story of Caius Toranius, who betrayed his affectionate
and excellent father to the triumvirate, Dr Paley thus proceeds:—
“ Now, the question is, whether, if this story were related to the wild boy caught some years ago in the woods of Hano¬
ver, or to a savage without experience and without instruction, cut off in his infancy from all intercourse with his species,
and consequently under no possible influence of example, authority, education, sympathy, or habit; whether, I say, such a
one would feel, upon the relation, any degree of that sentiment of disapprobation of Toranius's conduct which we feel or not ?
“ They who maintain the existence of a moral sense, of innate maxims, of a natural conscience—that the love of virtue
and hatred of vice are instinctive, or the perception of right or wrong intuitive (all of which are only different ways of
expressing the same opinion), affirm that he would.
“ They who deny the existence of a moral sense, &c. affirm that he would not.
“ And upon this issue is joined”—(Principles of Moral and Political Philosophy, B. I. chap. 5.)
To those who are at all acquainted with the history of this dispute, it must appear evident that the question is here com¬
pletely mis-stated; and that, in the whole of Dr Paley’s subsequent argument on the subject, he combats a phantom of his
own imagination. The opinion which he ascribes to his antagonists has been loudly and repeatedly disavowed by all the
most eminent moralists who have disputed Locke’s reasonings against innate practical principles; and is, indeed, so very ob¬
viously absurd, that it never could have been for a moment entertained by any person in his senses.
Did it ever enter into the mind of the wildest theorist to imagine that the sense of seeing would enable a man brought
up, from the moment of his birth, in utter darkness, to form a conception of light and colours ? But would it not be
equally rash to conclude from the extravagance of such a supposition, that the sense of seeing is not an original part of the
human frame ?
The above quotation from Paley forces me to remark, farther, that, in combating the supposition of a moral sense, he has
confounded together, as only different ways of expressing the same opinion, a variety of systems, which are regarded by all our
best philosophers, not only as essentially distinct, but as in some measure standing in opposition to each other. The sys¬
tem of Hutcheson, for example, is identified with that of Cudworth. But although, in this instance, the author’s logical
discrimination does not appear to much advantage, the sweeping censure thus bestowed on so many of our most celebrated
ethical theories, has the merit of throwing a very strong light on that particular view of the subject which it is the aim of
his reasonings to establish, in contradiction to them all.
3 See the section on Instinct. Sect. XVI. of that work.
DISS. I. PART II. 2 F
226
preliminary dissertations.
prior to experience, and independent of instruc¬
tion,” “ that the sexes of animals seek each
other; that animals cherish their offspring1 2 3;
that the young quadruped is directed to the teat
of its dam; that birds build their nest, and
brood with so much patience upon their eggs;
that insects, which do not sit upon their eggs,
deposit them in those particular situations in
which the young, when hatched, find their ap¬
propriate food; that it is instinct which carries
the salmon, and some other fish, out of the sea
into rivers, for the purpose of shedding their
spawn in fresh water.”1
In Dr Paley’s very able and convincing rea¬
sonings on these various points, he has undoubt¬
edly approached nearer to the spirit of what has
been ironically called Scottish philosophy,4 than
any of Mr Locke’s English disciples, since the
time of Dr Butler; a circumstance which, when
compared with the metaphysical creed of his ear¬
lier years, reflects the greatest honour on the can¬
dour and fairness of his mind, and encourages the
hope, that this philosophy, where it is equally
sound, will gradually and silently work its way
among sincere inquirers after truth, in spite of
the strong prejudices which many of our south¬
ern neighbours still appear to entertain against
it. The extravagancies of Darwin, it is pro¬
bable, first opened Dr Paley’s eyes to the dan¬
gerous tendency of Locke’s argument against
innate principles, when inculcated without due
limitations.5
With this very faint outline of the specula¬
tions of Locke’s chief successors in Scotland,
prior to the close of Dr Reid’s literary labours,
i shall for the present finish my review of the
metaphysical pursuits of the eighteenth century.
The long period which has since elapsed has been
too much crowded with great political events to
favour the growth of abstract science in any of
its branches; and of the little which appears to
have been done, during this interval, in other
parts of Europe, towards the advancement of
true philosophy, the interrupted communication
between this island and the Continent left us for
many years in a state of almost total ignorance.
This chasm in our information concerning fo¬
reign literature, it may not be a difficult task
for younger men to supply. At my time of life
it would be folly to attempt it; nor, perhaps, is
any author who has himself been so frequently
before the public, the fittest person to form an
impartial estimate of the merits of his living
contemporaries. Now, however, when peace is
at length restored to the world, it may reason •
ably be hoped that the human mind will again
resume her former career with renovated ener¬
gy ; and that the nineteenth century will not
1 Paley’s Natural Theology, p. 324. „ ^ „ , , „ T
2 May I take the liberty of requesting the reader to compare a few pages of Dr Paley s Section on Instinct, beginning
“ i am not ignorant of the theory which resolves instinct into sensation," &c. with some remarks made by the author ot this Dis¬
sertation, in an Account of the Life and Writings of Dr Reid ? See the passage in section second, beginning thus, In a
very original work, on which I have already hazarded some criticisms," &c. As both publications appeared about the same time
(in the year 1802), the coincidence, in point of thought, must have been wholly accidental, and as such anords no slight
presumption in favour of its soundness. ,
3 When Dr Paley published his Principles of Moral and Political Philosophy, he seems to have attached himselt much too
slavishly to the opinions of Bishop Law, to whom that work is inscribed. Hence, probably, his anxiety to disprove the
existence of the moral faculty. Of the length to which Law was disposed to carry Locke’s argument against innate prin¬
ciples, he has enabled us to judge by his own explicit declaration : “ I take implanted senses, instincts, appetites, passions,
and affections, &c. to be a remnant of the old philosophy, which used to call every thing innate that it could not account tor;
and therefore heartily wish, that they were in one sense all eradicated, which was undoubtedly the aim ot that g;reat author
last mentioned (Mr Locke), as it was a natural consequence of his first book.”—(Law’s Translation ot Archbishop King
On the Origin of Evil, p. 79, note.) .
In justice, however, to Dr Law, it must be observed, that he appears to have been fully aware that the dispute about in¬
nate principles was in a great measure verbal. “ It will really,” says he, “ come to the same thing with regard to the mo¬
ral attributes of God and the nature of virtue and vice, whether the Deity has implanted these instincts and affections in
us or has framed and disposed us in such a manner, has given us such powers, and placed us in such circumstances, that
we must necessarily acquire them."—(Ibid.) But if Dr Law was aware of this, why should he and his followers have attach¬
ed such infinite importance to the controversy ?
DISSERTATION FIRST.
227
yield to the eighteenth in furnishing materials
to those who may hereafter delight to trace the
progressive improvement of their species. In
the meantime, instead of indulging myself in
looking forward to the future, I shall conclude
this section with a few general reflections sug¬
gested by the foregoing retrospect.
Among these reflections, what chiefly strikes
my own mind is the extraordinary change which
has gradually and insensibly taken place since
the publication of Locke’s Essay, in the mean¬
ing of the word Metaphysics; a word former¬
ly appropriated to the ontology and pneuma-
tology of the schools, but now understood as
equally applicable to all those inquiries, which
have for their object to trace the various bran¬
ches of human knowledge to their first principles
in the constitution of our nature.1 This change
can be accounted for only by a change in the
philosophical pursuits of Locke’s successors; a
change from the idle abstractions and subtleties
of the dark ages, to studies subservient to the
culture of the understanding; to the successful
exercise of its faculties and powers; and to a
knowledge of the great ends and purposes of our
being. It may he regarded, therefore, as a pal¬
pable and incontrovertible proof of a corres¬
ponding progress of reason in this part of the
world.
On comparing together the multifarious studies
now classed together under the title of Meta¬
physics, it will be found difficult to trace any
common circumstance but this, that they all re¬
quire the same sort of mental exertion for their
prosecution ; the exercise, I mean, of that power
(called by Locke Reflection) by which the mind
turns its attention inwards upon its own opera¬
tions, and the subjects of its own consciousness.
In researches concerning our intellectual and
active powers, the mind directs its attention to
the faculties which it exercises, or to the pro¬
pensities which put these faculties in motion.
In all the other inquiries which fall under the
province of the Metaphysician, the materials of
his reasoning are drawn chiefly from his own
internal resources. Nor is this observation less
applicable to speculations which relate to things
external, than to such as are confined to the
thinking and sentient principle within him. In
carrying on his researches (for example) con¬
cerning hardness, softness, figure, and motion,
he finds it not less necessary to retire within
himself, than in studying the laws of imagina¬
tion or memory. Indeed, in such cases, the
whole aim of his studies is to obtain a more pre¬
cise definition of his ideas, and to ascertain the
occasions on which they are formed.
From this account of the nature and object of
metaphysical science, it may he reasonably ex¬
pected, that those with whom it is a favourite
and habitual pursuit, should acquire a more than
ordinary capacity of retiring, at pleasure, from
the external to the internal world. They may
be expected also to acquire a disposition to ex¬
amine the origin of whatsoever combinations
they may find established in the fancy, and a
superiority to the casual associations which warp
common understandings. Hence an accuracy
and a subtlety in their distinctions on all sub¬
jects, and those peculiarities in their views which
are characteristical of unbiassed and original
thinking. But, perhaps, the most valuable fruit
of their researches, is that scrupulous precision
in the use of language, upon which, more than
upon any one circumstance whatever, the logi¬
cal accuracy of our reasonings, and the justness
of our conclusions, essentially depend. Accord¬
ingly it will he found, on a review of the history
of the moral sciences, that the most important
steps which have been made in some of those,
apparently the most remote from metaphysical
pursuits (in the science, for example, of politi¬
cal economy), have been made by men trained
to the exercise of their intellectual powers by
1 The following is the account of Metaphysics given by Hobbes :—u There is a certain Philosophia prima, on which all
other Philosophy ought to depend; and consisteth principally in right limiting of the significations of such appellations, or
names, as are of all others the most universal: which limitations serve to avoid ambiguity and equivocation in reasoning,
and are commonly called Definitions; such as are the Definitions of Body, Time, Place, Matter, Form, Essence, Sub¬
ject, Substance, Ac*, dent, Power, Act, Finite, Infinite, Quantity, Quality, Motion, Action, Passion, and divers others, ne¬
cessary to the explaining of a man’s conceptions concerning the nature and generation of bodies. The explication (that is,
the settling of the meaning) of which, and the like terms, is commonly in the schools called Metaphysics."—(Moral and Poli¬
tical Works. Folio Edit. London, 1750, p. 399.)
228
PRELIMINARY DISSERTATIONS.
early habits of abstract meditation. To this fact
Burke probably alluded, when he remarked, that
(i by turning the soul inward on itself, its forces
are concentered, and are fitted for stronger and
bolder flights of science; and that in such pur¬
suits, whether we take, or whether we lose the
game, the chase is certainly of service.” The
names of Locke, of Berkeley, of Hume, of
Quesnai, of Turgot, of Morellet, and above all,
of Adam Smith, will at once illustrate the truth
of these observations, and show, that, in com¬
bining together, in this Dissertation, the sciences
of Metaphysics, of Ethics, and of Politics, I have
not adopted an arrangement altogether capri¬
cious. 1
In farther justification of this arrangement, I
might appeal to the popular prejudices so in¬
dustriously fostered by many, against these
three branches of knowledge, as ramifications
from one common and most pernicious root.
How often have Mr Smith’s reasonings in fa¬
vour of the freedom of trade been ridiculed as
metaphysical and visionary ! Nay, but a few
years have elapsed, since this epithet (accom¬
panied with the still more opprobrious terms of
Atheistical and Democratical) was applied to
the argument then urged against the morality
and policy of the slave-trade; and, in general,
to every speculation in which any appeal was
made to the beneficent arrangements of nature,
or to the progressive improvement of the human
race. Absurd as this language was, it could
not, for a moment, have obtained any currency
with the multitude, had there not been an ob¬
vious connection between these liberal doc¬
trines, and the well known habits of logical
thinking, which so eminently distinguished their
authors and advocates. Whatever praise, there¬
fore, may be due to the fathers of the modern
science of political economy, belongs, at least in
part (according to the acknowledgment of their
most decided adversaries), to those abstract stu¬
dies by which they were prepared for an analy¬
tical investigation of its first and fundamental
principles.
Other connections and affinities between Poli¬
tical Economy and the Philosophy of the Hu¬
man Mind will present themselves afterwards.
At present I purposely confine myself to that
which is most obvious and indisputable.
The influence of metaphysical studies may be
also perceived in the philosophical spirit so large¬
ly infused into the best historical compositions
of the last century. This spirit has, indeed,
been often perverted to pernicious purposes; but
who can doubt, that, on the whole, both history
and philosophy have gained infinitely by the
alliance ?
How far a similar alliance has been advanta¬
geous to our poetry, may be more reasonably
questioned. But on the most unfavourable sup¬
position it must be admitted, that the number
of poetical readers has thereby been greatly in¬
creased, and the pleasures of imagination pro¬
portionally communicated to a wider circle.
The same remark may be extended to the study
of philosophical criticism. If it has not contri¬
buted to the encouragement of original genius
in the fine arts, it has been followed by a much
more beneficial result in diffusing a relish for the
beautiful and the elegant; not to mention its in¬
fluence in correcting and fixing the public taste,
by the precision and steadiness of the principles
to which it appeals.2
Another instance, still more important, of the
practical influence of metaphysical science, is
the improvement which, since the time of Locke,
has become general in the conduct of education,
1 It furnishes no objection to these remarks, that some of our best treatises on questions of political economy have pro¬
ceeded from men who were strangers to metaphysical studies. It is enough for my purpose if it be granted, that it was by
habits of metaphysical thinking that the minds of those authors were formed, by whom political economy was first exalted
to the dignity of a science. To a great proportion even of the learned, the rules of a sound logic are best taught by ex¬
amples ; and when a precise and well-defined phraseology is once introduced, the speculations of the most ordinary writers
assume an appearance (sometimes, it must be owned, a very fallacious one) of depth and consistency.
Fontenelle remarks, that a single great man is sufficient to accomplish a change in the taste of his age, and that the per¬
spicuity and method for which Descartes was indebted to his mathematical researches, were successfully copied by many of
his contemporaries who were ignorant of mathematics. A similar observation will he found to apply, with still greater
force, to the models of metaphysical analysis and of logical discussion, exhibited in the political works of Hume and of
Smith.
2 See some admirable remarks on this subject by Gray, in his comments on the Jo of Plato. (Edition of Gray, by
Mathias.)
DISSERTATION FIRST.
229
both private and public. In the former case,
the fact is universally acknowledged. But even
in our universities (notwithstanding the prover¬
bial aversion of most of them to everything
which savours of innovation) what a change has
been gradually accomplished since the beginning
of the eighteenth century ! The studies of On¬
tology, of Pneumatology, and of Dialectics,
have been supplanted by that of the Human
Mind, conducted with more or less success, on
the plan of Locke’s Essay ; and, in a few seats
of learning, by the studies of Bacon’s Method of
Inquiry, of the Principles of Philosophical Criti¬
cism, and of the Elements of Political Economy.
In all this an approach has been made or at¬
tempted, to what Locke so earnestly recommend¬
ed to parents, <e that their children’s time should
be spent in acquiring what may be useful to
them when they come to be men.” Many other
circumstances, no doubt, have contributed their
share in producing this revolution ; but what in¬
dividual can be compared to Locke in giving the
first impulse to that spirit of reform by which it
has been established ?x
In consequence of the operation of these
causes, a sensible change has taken place in the
style of English composition.9 The number of
idiomatical phrases has been abridged; and the
language has assumed a form more systematic,
precise, and luminous. The transitions, too, in
our best authors, have become more logical, and
less dependent on fanciful or verbal associations.
If by these means our native tongue has been
rendered more unfit for some of the lighter species
of writing, it has certainly gained immensely as
an instrument of thought, and as a vehicle of
1 Under this head of education may also be mentioned the practical improvements which, during the course of the last
century, have taken place in what Lord Bacon calls the traditive part of logic. I allude here not only to the new arrange¬
ments in the Lancasterian Schools, by which the diffusion of the art of reading among the poorer classes of the community
is so wonderfully facilitated and extended, but to those admirable elementary works which have opened a ready and speedy
access to the more recondite truths of the severer sciences. How much these have contributed to promote the progress of
mathematical knowledge in France may be judged of from an assertion of Condorcet, that two years spent under an able
teacher now carry the student beyond the conclusions which limited the researches of Leibnitz and of Newton. The Es¬
says lately published on this subject by M. Lacroix (Essais sur VEnseignement en General, et sur celui des Mathematiques en
particulier. Paris, 1805) contain many valuable suggestions ; and, beside their utility to those who are concerned in the
task of instruction, may justly be considered as an accession to the Philosophy of the Human Mind.
2 See some judicious remarks on this subject, in Mr Godwin’s Inquirer, p. 274. In the opinion of this author, “ the
English language is now written with more grammatical propriety than by the best of our ancestors ; and with a much
higher degree of energy and vigour. The spirit of philosophy has infused itself into the structure of our sentences.” He
remarks farther, in favour of the present style of English composition, “ that it at once satisfies the understanding and the
ear.” The union of these two excellencies certainly constitutes the perfection of writing. Johnson boasts, and with truth,
in the concluding paper of the Rambler, that he had “ added something to our language in the elegance of its construction,
and something in the harmony of its cadence;” but what a sacrifice did he make to these objects, of conciseness, of simpli¬
city, and of (what he has himself called) Genuine Anglicism. To accomplish the same ends, without any sacrifice of these
higher merits, has been one of the chief aims of the most eminent among his successors.
As an instrument of thought and a medium of scientific communication, the English language appears to me, in its pre¬
sent state, to be far superior to the French. Diderot, indeed (a very high authority), has, with much confidence, asserted
the contrary; and it is but fair to let him speak for himself: “ J’ajouterois volontiers que la marche didactique et reglee
a laquelle notre langue est assujettie la rend plus propre aux sciences; et que par les tours et les inversions que le Grec,
le Latin, ITtalien, 1’Anglois, se permettent, ces langues sont plus avantageuses pour les lettres: Que nous pouvons mieux
qu’ aucun autre peuple faire parler I’esprit; et que le bon sens choisiroit la langue Francoise; mais que ITmagination et
les passions donneroient la preference aux langues anciennes et a celles de nos voisins: Qu’il faut parler Francois dans la
societd et dans les dcoles de Philosophic; et Grec, Latin, Anglois, dans les chaires et sur le Theatre: Que notre langue
seroit celle de la verite, si jamais elle revient sur la terre; et que la Grecque, la Latine, et les autres seroient les langues
de la fable et du mensonge. Le Francois est fait pour instruire, edairer, et convaincre; le Grec, le Latin, ITtalien, 1’Ang¬
lois, pour persuader, emouvoir, et tromper; parlez Grec, Latin, Italien au peuple, mais parlez Francois au sage.”—
(CEuvres de Diderot, Tome II. pp. 70, 71- Amsterdam, 1772.)
These peculiar excellencies of the French language are ascribed, in part, by Diderot, to the study of the Aristotelian Phi¬
losophy (Ibid. p. 7.) I do not well see what advantage France should, in this respect, have enjoyed over England ; and
since that philosophy fell into disrepute, it will scarcely be alleged that the habits of thinking cultivated by Locke’s dis¬
ciples have been less favourable to a logical rigour of expression than those of any contemporary sect of French metaphy¬
sicians.
A later French writer has, with far greater justice, acknowledged the important services rendered to the French lan¬
guage, by the gentlemen of the Port Royal Society. “ L’Ecole de Port Royal, feconde en penseurs, illustre'e par les ^cri-
vains les plus purs, par les drudits les plus laborieux du siecle de Louis XIY. eut deja rendu parmi nous un assez grand
service k la philosophie par cela seul qu’elle a puissament concouru a fixer notre langue, h lui donner ce caractere de
precision, de clartd, d’exactitude, qui la rend si favorable aux operations de I’esprit.”—Hist. Comparee, &c. Tome II.
P- 45-)
Mr Gibbon also has remarked, how much “ the learned Society of Port Royal contributed to establish in France a taste
for just reasoning, simplicity of style, and philosophical method.” The improvement, in all these respects, of our English
writers, during the same period, is, in my opinion, much more remarkable.
230
PRELIMINARY DISSERTATIONS.
knowledge. May I not also add, that the study
of it has been greatly facilitated to foreigners;
and that in proportion to its rejection of colloqui¬
al anomalies, more durable materials are sup¬
plied to the present generation for transmitting
their intellectual acquisitions to posterity ?
But granting the truth of these reflections, it
may still he asked, what is the amount of the
discoveries brought to light by the metaphysical
speculations of the eighteenth century? Or
rather, where are the principles to be found, of
which it can he justly said, that they unite the
suffrages, not of the whole, but even of the ma¬
jority of our present philosophers ? The question
has been lately put and urged, with no common
ability, by a foreign academician.
“ The diversity of doctrines (says M. de
Bonald) has increased, from age to age, with the
number of masters, and with the progress of
knowledge ; and Europe, which at present pos¬
sesses libraries filled with philosophical works,
and which reckons up almost as many philoso¬
phers as writers; poor in the midst of so much
riches, and uncertain, with the aid of all its
guides, which road it should follow; Europe,
the centre and the focus of all the lights of the
world, has yet its philosophy only in expecta¬
tion.”1 2
In proof of this assertion, the author appeals
to the Comparative History of Philosophical Sys¬
tems relative to the Principles of Human Knowledge,
by M. Degerando ; and after a variety of acute
strictures on the contradictory systems there de ¬
scribed, sums up his argument in the following
words:
“ Thus, the Comparative History of Philosophi¬
cal Systems is nothing else than a History of the
Variations of philosophical schools, leaving no
other impression upon the reader than an in¬
surmountable disgust at all philosophical re¬
searches ; and a demonstrated conviction of the
impossibility of raising an edifice on a soil so
void of consistency, and so completely surrounded
by the most frightful precipices. About what then
are philosophers agreed ? What single point
have they placed beyond the reach of dispute ?
Plato and Aristotle inquired, What is science?
What is knowledge ? And we, so many ages after
these fathers of philosophy ; we, so proud of the
progress of human reason, still continue to re¬
peat the same questions; vainly pursuing the
same phantoms which the Greeks pursued two
thousand years ago.”®
In reply to this hold attack on the evidence of
the moral sciences, it may suffice to recal to our
recollection the state of physical science not more
than two centuries ago. The argument of M.
de Bonald against the former is, in fact, precisely
the same with that ascribed by Xenophon to So¬
crates against those studies which have immor¬
talised the names of Boyle and Newton; and
which, in our own times, have revealed to us all
the wonders of the modern chemistry. What¬
ever contradictions, therefore, may yet exist in
our metaphysical doctrines (and of these con¬
tradictions many more than is commonly sus¬
pected will be found to be merely verbal), why
should we despair of the success of future ages
in tracing the laws of the intellectual world,
which, though less obvious than those of the
material world, are not less the natural and le¬
gitimate objects of human curiosity?
Nor is it at all wonderful that the beneficial
effects of metaphysical habits of thinking should
have been first perceived in political economy,
and some other sciences to which, on a super¬
ficial view, they may seem to have a very remote
relation; and that the rise of the sap in the tree
of knowledge should be indicated by the germs
at the extremities of the branches, before any
1 Recherches Philosophiques, &c. p. 2. Paris, 1818.
2 Ibid. pp. 58, 59.
On the other hand, may it not be asked, if the number of philosophical systems be greater than that of the sects which
at present divide the Christian church ? The allusion here made to Bossuet’s celebrated History of the Variations, shows
plainly, that the similarity of the two cases had not been overlooked by the ingenious writer; and that the only effectual
remedy which, in his opinion, can be applied to either, is to subject once more the reason, both of philosophers and of di-
rines, to the paramount authority of an infallible guide. The conclusion is such as might have been expected from a good
Catholic; but I trust that, in this country, it is not likely to mislead many of my readers. Some recent conversions to
Popery, however, which, in consequence of views similar to those of M. de Bonald, have taken place among the philoso¬
phers of Germany, afford a proof that, in the present political state of Europe, the danger of a temporary relapse into the
suqerstitions of the Church of Borne, how slight soever, ought not to be regarded as altogether visionary. (See Lectures on
the History of Literature, by Frederick Schlegel, Vol. II. pp. 65, 88, 89, 175, 187. English Translation. Edinburgh.)
DISSERTATION FIRST.
231
visible change is discernible in the trunk. The
sciences, whose improvement during the last
century has been generally acknowledged, are
those which are most open to common observa¬
tion ; while the changes which have taken place
in the state of metaphysics, have attracted the
notice of the few alone who take a deep interest
in these abstract pursuits. The swelling of the
buds, however, affords a sufficient proof that the
roots are sound, and encourages the hope that
the growth of the trunk, though more slow, will,
in process of time, be equally conspicuous with
that of the leaves and blossoms.
I shall close this part of my Dissertation with
remarking, that the practical influence of such
speculations as those of Locke and of Bacon is
to be traced only by comparing, on a large scale,
the state of the human mind at distant pe¬
riods. Both these philosophers appear to have
been fully aware (and I know of no philosopher
before them of whom the same thing can be
said), that the progressive improvement of the
species is to be expected less from the culture of
the reasoning powers, strictly so called, than from
the prevention, in early life, of those artificia.
impressions and associations, by means of which,
when once rivetted by habit, the strongest rea¬
son may be held in perpetual bondage. These
impressions and associations may he likened to
the slender threads which fastened Gulliver to
the earth; and they are to be overcome, not by
a sudden exertion of intellectual force, but by
the gradual effect of good education, in break¬
ing them asunder one by one. Since the re¬
vival of letters, seconded by the invention of
printing, and by the Protestant Reformation,
this process has been incessantly going on, all
over the Christian world; but it is chiefly in
the course of the last century that the result has
become visible to common observers. How many
are the threads which, even in Catholic coun¬
tries, have been broken by the writings of Locke!
How many still remain to be broken, before the
mind of man can recover that moral liberty which,
at some future period, it seems destined to en¬
joy !
NOTES.
NOTES AND ILLUSTRATIONS.
Notes The chief purpose of these Notes and Illus-
^ trations, is to verify some of the more important
Illustrations. . . . • .i p • tt* a • i
views contained in the foregoing Historical
Sketch. The errors into which I have frequent¬
ly been led by trusting to the information of
writers, who, in describing philosophical sys¬
tems, profess to give merely the general results
of their researches, unauthenticated by particu¬
lar references to the original sources, have long
convinced me of the propriety, on such occa¬
sions, of bringing under the eye of the reader,
the specific authorities on which my statements
proceed. Without such a check, the most faith¬
ful historian is perpetually liable to the suspi¬
cion of accommodating facts to his favourite
theories; or of unconsciously blending with the
opinions he ascribes to others, the glosses of his
own imagination. The quotations in the fol- Notes
lowing pages, selected principally from books, and
. T, Illustrations,
not now in general circulation, may, I hope, at
the same time, be useful in facilitating the la¬
bours of those who shall hereafter resume the
same subject, on a scale more susceptible of the
minuteness of literary detail.
For a few short biographical digressions, with
which I have endeavoured to give somewhat of
interest and relief to the abstract and unattrac¬
tive topics which occupy so great a part of my
Discourse, I flatter myself that no apology is
necessary; more especially, as these digressions
will in general be found to throw some addi¬
tional light on the philosophical or the political
principles of the individuals to whom they re¬
late.
Note A, p. 15.
Sir Thomas More, though, towards the close of
his life, he became “ a persecutor even unto blood,
defiling with cruelties those hands which were
never polluted with bribes1 was, in his earlier
and better days, eminently distinguished by the
humanity of his temper, and the liberality of his
opinions. Abundant proofs of this may be col¬
lected from his Letters to Erasmus; and from the
sentiments, both religious and political, indirect¬
ly inculcated in his Utopia. In contempt for the
ignorance and profligacy of the monks, he was
not surpassed by his correspondent; and against
various superstitions of the Romish church, such
as the celibacy of priests, and the use of images
in worship, he has expressed himself more de¬
cidedly than could well have been expected from
a man placed in his circumstances. But these
were not the whole of his merits. His ideas on
Criminal Law are still quoted with respect by
the advocates for a milder code than has yet
been introduced into this country; and, on the
subject of toleration, no modern politician has
gone farther than his Utopian Legislators.
The disorders occasioned by the rapid pro¬
gress of the Reformation, having completely
shaken his faith in the sanguine speculations of
his youth, seem at length, by alarming his fears
as to the fate of existing establishments, to have
1 Burnet.
DISSERTATION FIRST.
233
Notes unhinged his understanding, and perverted his
Illustrations- moral feelings. The case was somewhat the
same with his friend Erasmus, who, as Jortin
remarks, t£ began in his old days to act the
zealot and the missionary with an ill grace, and
to maintain, that there were certain heretics who
might be put to death as blasphemers and riot¬
ers” (pp. 428, 481). In the mind of Erasmus,
other motives, it is not improbable, concurred;
his biographer and apologist being forced to ac¬
knowledge, that 44 he was afraid lest Francis,
and Charles, and Ferdinand, and George, and
Henry VIII., and other persecuting princes,
should suspect that he condemned their cruel
conduct.”—(Ibid. p. 481.)
Something, it must at the same time be ob¬
served, may be alleged in behalf of these two
illustrious persons: not, indeed, in extenuation
of their unpardonable defection from the cause
of religious liberty, but of their estrangement
from some of their old friends, who scrupled not
to consider as apostates and traitors, all those
who, while they acknowledged the expediency
of ecclesiastical reform, did not approve of the
violent measures employed for the accomplish¬
ment of that object. A very able and candid
argument on this point may be found in Bayle,
Article Castellan, Note Q.
Note B, p. 16.
The following short extract will serve to con¬
vey a general idea of Calvin’s argument upon
the subject of usury.
44 Pecunia non parit pecuniam. Quid mare ?
quid domus, ex cujus locatione pensionem per-
cipio ? an ex tectis et parietibus argentum pro-
prie nascitur ? Sed et terra producit, et mari
advehitur quod pecuniam deinde producat, et
habitationis commoditas cum certa pecunia pa-
rari commutarive solet. Quod si igitur plus ex
negotiatione lucri percipi possit, quam ex fundi
cujusvis proventu : an feretur qui fundum ste-
niem fortasse colono locaverit ex quo mercedem
vet proventum recipiat sibi, qui ex pecunia
fructum aliquem perceperit, non feretur ? et qui
pecunia fundum acquirit, annon pecunia ilia ge¬
neral alteram annuam pecuniam? Unde verc No*ea
mercatoris lucrum? Ex ipsius, inquies, dili-Illus“"ations<
gentia atque industria. Quis dubitat pecuniam
vacuam inutilem omnino esse ? neque qui a me
mutuam rogat, vacuam apud se habere a me
acceptam cogitat. Non ergo ex pecunia ilia
lucrum accedit, sed ex proventu. Mae igitur
rationes subtiles quidem sunt, et speciem quan-
dam habent, sed ubi propius expenduntur, reipsa
concidunt. Nunc igitur conclude, judicandum
de usuris esse, non ex particular! aliquo Scrip-
turse loco, sed tantum ex aequitatis regula.”—
(Calvini Epistolce.J
Note C, p. 22.
The prevailing idea among Machiavel’s con¬
temporaries and immediate successors certainly
was, that the design of the Prince was hostile to
the rights of mankind; and that the author was
either entirely unprincipled, or adapted his pro¬
fessed opinions to the varying circumstances of
his own eventful life. The following are the
words of Bodinus, born in 1530, the very year
when Machiavel died; an author whose judg¬
ment will have no small weight with those who
are acquainted with his political writings:
44 Machiavel s’est bien fort mesconte, de dire que
1’estat populaire est le meilleur:1 et neantmoins
ayant oublie sa premiere opinion, il a tenu en
un autre lieu,2 que pour restituer ITtalie en sa
liberte, il faut qu’il n’y ait qu’un Prince; et de
fait, il s’est efforce de former un estat le plus
tyrannique du monde; et en autre lieu* il con-
fesse, que 1’estat de Venice est le plus beau de
tous, lequel est une pure Aristocratic, s’il en fut
onques: tellement qu’il ne scait a quoi se tenir.”
—(De la mpublique, Liv. vi. chap. iv. Paris,
1576). In the Latin version of the above pas¬
sage, the author applies to Machiavel the phrase,
Homo levissimus ac nequissimus.
One of the earliest apologists for Machiavel
was Albericus Gentilis, an Italian author ot
whom some account will be given afterwards.
His words are these : 44 Machiavel, a warm pa-
negyrist and keen asserter of democracy; born,
educated, promoted under a republican govern-
1 Discourses upon Livy.
DISS. I. PART II.
2 Prince, Book i. c. ix.
Discourses upon Livy.
2 G
234
PRELIMINARY DISSERTATIONS.
Notes ment, was in the highest possible degree hostile
Illustrations-to tyranny. The scope of his work, according-
ly, is not to instruct tyrants; but, on the con¬
trary, by disclosing their secrets to their op¬
pressed subjects, to expose them to public view,
stripped of all their trappings.” He afterwards
adds, that “ Machiavel’s real design was, under
the mask of giving lessons to sovereigns, to open
the eyes of the people; and that he assumed
this mask in the hope of thereby securing a freer
circulation to his doctrines.”—(De Legationibus,
Lib. hi. c. ix. Lond. 1585). The same idea was
afterwards adopted and zealously contended for
by Wicquefort, the author of a noted hook en¬
titled the Ambassador ; and by many other wri¬
ters of a later date.1 Bayle, in his Dictionary,
has stated ably and impartially the arguments
on both sides of the question: evidently leaning,
however, very decidedly, in his own opinion, to
that of Machiavel’s apologists.
The following passage from the excellent work
of M. Simonde de Sismondi on the Literature of
the South, appears to me to approach very near
to the truth in the estimate it contains both of
the spirit of the Prince, and of the character of
the author. u The real object of Machiavel can¬
not have been to confirm upon the throne a ty¬
rant whom he detested, and against whom he
had already conspired; nor is it more probable
that he had a design to expose to the people the
maxims of tyranny, in order to render them
odious. Universal experience made them at
that time sufficiently known to all Italy; and
that infernal policy which Machiavel reduced to
principles, was, in the sixteenth century, prac¬
tised by every government. There is rather, in
his manner of treating it, a universal bitterness
against mankind; a contempt of the whole hu¬
man race; which makes him address them in
the language to which they had debased them¬
selves. He speaks to the interests of men, and to
their selfish calculations, as if he thought it use¬
less to appeal to their enthusiasm or to their
moral feelings.”
I agree perfectly with M. de Sismondi in con¬
sidering the two opposite hypotheses referred to Note*
in the above extract, as alike untenable; and have iuustra^ionii
only to add to his remarks, that, in writing the
Prince, the author seems to have been more un¬
der the influence of spleen, of ill-humour, and
of blasted hopes, than of any deliberate or sys¬
tematical purpose, either favourable or adverse
to human happiness. The prevailing sentiment
in his mind probably was, S* populus vult decipi,
decipiaiur.2
According to this view of the subject, Ma-
chiavel’s Prince, instead of being considered as
a new system of political morality, invented by
himself, ought to be regarded merely as a di¬
gest of the maxims of state policy then univer¬
sally acted upon in the Italian courts. If I he
not mistaken, it was in this light that the hook
was regarded by Lord Bacon, whose opinion
concerning it being, in one instance, somewhat
ambiguously expressed, has been supposed by
several writers of note (particularly Bayle and
Mr Roscoe) to have coincided with that quoted
above from Albericus Gentilis. To me it ap¬
pears, that the very turn of the sentence ap¬
pealed to on this occasion is rather disrespectful
than otherwise to Machiavel’s character. <( Est
itaque quod gratias agamus Machiavellio et hu-
jusmodi scriptoribus, qui aperte et indissimulanter
proferunt, quid homines facere soleant, non quid
deheant.”—(De Aug. Scient. Lib. vii. cap. ii.)
The best comment, however, on these words, is
to he found in another passage of Bacon, where
he has expressed his opinion of Machiavel’s mo¬
ral demerits in terms as strong and unequivocal
as language can furnish. “ Quod enim ad ma-
las artes attinet; si quis Machiavellio se dederit
in disciplinam; qui prsecipit,” &c. &c. &c. See
the rest of the paragraph (De Aug. Scient. Lib.
viii. cap. ii.) See also a passage in Book vii.
chap. viii. beginning thus : “ An non et hoc ve-
rum est, juvenes multo minus Politicce quam
Ethicce auditores idoneos esse, antequam reli-
gione et doctrina de morihus et officiis plane in>
buantur; ne forte judicio depravati et corrupti,
in earn opinionem veniant, non esse rerum dif-
1 See in particular Rousseau Du Contrat Social, Liv. iii. c. vi.
2 Many traces of this misanthropic disposition occur in the historical and even in the dramatic works of Machiavel. It
is very justly observed by M. de Sismondi, that “ the pleasantry of his comedies is almost always mingled with gall. His
laughter at the human race is but the laughter of contempt.”
DISSERTATION FIRST.
235
Notes ferentias morales veras et solidas, sed omnia ex
Illustrations, utilitate.-—Sic enim Machiavellio dicere placet,
Quod si contigisset Ccesarem hello super alum fuisse,
Catilina ipso fuisset odiosior,” &c. &c. After
these explicit and repeated declarations of his
sentiments on this point, it is hard that Bacon
should have been numbered among the apolo¬
gists of Machiavel, by such high authorities as
Bayle, and the excellent biographer of Lorenzo
de Medicis.
It has been objected to me, that in the fore¬
going observations on the design of the Prince, I
have taken no notice of the author’s vindication
of himself and his writings, in his letter to
Zenobius Buondelmontius, annexed to the
old English translation of Machiavel, printed
at London in 1675 and 1680. In the preface to
this translation, we are told, that the letter in
question “ had never before been published in
any language, but lurked for above eighty years in
the private cabinets of his own kindred, or the
descendants of his admirers in Florence, till, in
the Pontificate of Urban VIII., it was procured by
the Jesuits and other busy bodies, and brought
to Rome with an intention to divert that wise
Pope from his design of making one of Nicholas
Machiavel’s name and family cardinal, as (not¬
withstanding all their opposition) he did, not
long after. When it was gotten into that city,
it wanted not those who had the judgment and
curiosity to copy it, and so at length came to en¬
joy that privilege which all rare pieces (even
the sharpest libels and pasquins) challenge at
that court, which is to be sold to strangers, one
of which, being a gentleman of this country,
brought it over with him at his return from
thence in 1645, and having translated it into
English, did communicate it to divers of his
friends; and by means of some of them, it hath
been my good fortune to be capable of making
thee a present of it; and let it serve as an
apology for our author and his writings, if thou
th'nkest he need any.”
As the translation of Machiavel, from which Notes
this advertisement is copied, is still in the hands uiu *"adi(r.s
of many readers in this country, it may not be
improper to mention here, that the letter in
question is altogether of English fabrication;
and (as far as I can learn) is quite unknown on
the Continent. It is reprinted at the end of the
second volume of Farneworth’s Translation of
Machiavel’s works, 1762, with the following
statement prefixed to it.1
“ The following letter having been printed in
all the editions of the old translation, it is here
given to the reader, though it certainly was not
written by Machiavel. It bears date in 1537,
and his death is placed by all the best historians
in 1530. There are, besides, in it many internal
marks, which to the judicious will clearly prove
it to be the work of some other writer, vainly
endeavouring at the style and manner of our
excellent author. The letter is indeed a spirited
and judicious defence of Machiavel and his
writings; but it is written in a style too inflated,
and is utterly void of that elegance and precision
which so much distinguish the works of the
Florentine secretary.”
To the author of this last translation we are
farther indebted for a very curious letter of Dr
Warburton’s, which renders it probable that the
forgery was contrived and carried into execution
by the Marquis of Wharton. I shall transcribe
the letter in Warburton’s words.
“ There is at the end of the English transla¬
tion of Machiavel’s works, printed in folio, 1680,
a translation of a pretended letter of Machiavel
to Zenobius Buondelmontius, in vindication of
himself and his writings. I believe it has been
generally understood to be a feigned thing, and
has by some been given to Nevil, he who wrote,
if I do not mistake, the Plato lledivims. But
many years ago, a number of the famous Marquis
of Wharton’s papers (the father of the Duke)
were put into my hands. Amongst these was
the press copy (as appearedby the printer’s marks,
where any page of the printed letter began and
ended) of this remarkable letter in the Marquis’s
hand-writing, as I took it to be, compared with
1 In a book published 1816, this letter is referred to without any expression of doubt as to its authenticity. See
Milleb’s Lectures on the Philosophy of Modern History, Dublin, 1816, p. 17-
236
PRELIMINARY DISSERTATIONS.
Notes other papers of his. The person who intrusted
Illustrations me these papers, and who I understood had
given them to me, called them back out of my
hands. This anecdote I communicated to the
late Speaker; and, at his desire, wrote down the
substance of what I have told you, in his book
of the above edition.—W. Gloucester.”1
From a memoir read before the French Insti¬
tute in July 1814, by M. Daunou,2 it appears
that some new light has been lately thrown on
the writings and life of Machiavel by the dis¬
covery of some of his unpublished papers. The
following particulars cannot fail to be gratifying
to many of my readers.
« M. Ginguene continue son Histoire de la Lit-
terature Italienne. et vient de communiquer a
la classe Tun des articles qui vont composer le
septieme tome de cette histoire. C’est un tableau
de la vie et des ecrits de Nicolas Machiavel. La
vie de cet ecrivain celebre est le veritable com-
mentaire de ses livres ; et jusqu’ici ce commen-
taire etoit reste fort incomplet. Par exemple, on
se bornait k dire, que la republique de Florence,
dontil etoit le secretaire, Favoit charge de diverses
missions politiques a la cour de France, a la
cour de Rome, aupres du Due de Valentinois,
aupres de FEmpereur, au camp de Pise, &c. &c.
M. Ginguene le suit annee par annee dans toutes
ses legations, il en fait connditre Fobjet et les
principales circonstances. Cette vie de vient ainsi
une partie essentielle de Fhistoire de Florence,
et tient meme a celle des puissances qui etoient
alors en relation avec cette republique. On lit peu
dans la collection des CEuvres de Machiavel, ses
correspondances politiques, qui neanmoins offrent
tous ces details et jettent un grand jour sur
son caractere et sur ses intentions. Malheu-
reusement, ce jour lui est peu favorable, et ne
nous eclaire que trop sur le veritable sens dans
lequel doit etre pris son Traite du Prince si
diversement juge. L’une des pieces les plus
curieuses et les plus decisives est une lettre
qu’il ecrivit de la campagne ou il s’etoit retir^ Notes
apres la rentree des Medicis a Florence II inustratjons>
venoit d’etre destitue de ses emplois; implique
dans une conspiration contre ces princes, il
avoit ete incarcere, mis a la torture, et juge
innocent, soit qu’il le fut en effet, soit que les
tourmens n’eussent pu lui arracher Faveu de
sa faute. Il trace dans ce lettre le tableau de ses
occupations et de ses projets, des travaux et des
distractions qui remplissent ses journees. Pour
sortir d’une position voisine de la misere, il sent
la necessite de rentrer en grace avec les Medicis,
et n’en troupe pas de meilleur moyen que de
dedier le Traite du Prince qu’il vient d’achever
a Julien le Jeune, frere du Leon X., et a qui
ce Pape avoit confie le gouvernement de Flo¬
rence. Machiavel croit que son Traite ne peut
manquer d’etre agreable et utile a un prince,
et surtout a un nouveau prince. Quelque terns
apres, il fit en effet homage de ce livre, non a
Julien, mais a Laurent II. Cette lettre, qui
n’est connue en Italic, que depuis peu d’annees,
etoit encore ignoree en France. M. Ginguent
Fa traduite: il pense qu’elle ne laisse aucune
incertitude sur le but et les intentions de Fau-
teur du Traite du Prince.”—Some farther de¬
tails on this subject are to be found in a subse¬
quent memoir by the same author, read before
the French Institute in July 1815.
Soon after reading the above passage in M.
Daunou’s Report, I received nearly the same in¬
formation from the north of Italy. It cannot be so
well expressed as in the words of the writer :—
“ Pray tell Mr Stewart that there is a very
remarkable letter of Machiavel’s lately publish¬
ed, written to a private friend at the very time
he was engaged in the composition of the
Prince, and not only fixing the date of that
work, but explaining in a manner disgraceful
to the author, the use he made of it, in putting
it into the hands of the Medicis family. The
letter is besides full of character, and describes,
1 In a letter from Warburton to the Reverend Mr Birch, there is the following passage :—“ I told you, I think, I had
several of old Lord Wharton’s papers. Amongst the rest is a manuscript in his own handwriting, a pretended translation
of a manuscript apologetical epistle of Machiavel’s, to his friend Zenobio. It is a wonderful fine thing. There are the
nrinter’s marks on the manuscript, which makes me think it is printed. There is a postscript of Lord Wharton’s to it, by
which it appears this pretended translation was designed to prefix to an English edition of his works. As I know nothing of
the English edition of Machiavel, I wish you would make this out, and let me know.”—(Illustrations of the Literary
History of the 18f/i century, intended as a sequel to the Literary Anecdotes by John Nichols. Vol. II. p. 88.)
2 Rapport sur les Travaux de la Classe d'Histoire, &c. 1 Juillet, 1814.
DISSERTATION FIRST.
237
N«tes in a very lively manner, the life he was leading
illustrations. w^en driven away from Florence. This parti-
cular letter may be read at the end of the last
volume of Pignotti’s Storia della Toscana; a
book published here, but which was in all
the London shops before I came away. It is
to be found also with several others, which are
entertaining and curious, in a new collection
published at Florence in 1814, of Machiavel’s
public dispatches and familiar letters. By the
way, I must likewise tell Mr Stewart that my
late reading has suggested a slight criticism
upon one expression of his with regard to Ma¬
chiavel’s Prince^ where he calls it one of the
“ latest of his publications.” The fact is, that
the three great works were none of them pub¬
lished in his lifetime, nor for four years after
his death. They appear to have been all writ¬
ten at the same period of his life, during the
eight or ten years of leisure that were forced
upon him; and I believe it may he made out
from the works themselves, that the Prince was
composed and finished first of the three, then
the Discourses, and last of all the History. This
and the first having been written for the Medicis
family, the MSS. were in their hands, and they
published them; the Discourses were printed by
the care of some of his personal friends. If Mr
Stewart wishes to have the proof of all this in
detail, I can draw it out without any trouble.”
The foregoing passage will he read by many
with no common interest, when it is known
that it formed part of a letter from the late
Francis Horner, written a very few weeks be¬
fore his death. Independently of the satisfac¬
tion I feel in preserving a memorial of his kind
attention to his friends, at a period when he
was himself an object of such anxious solicitude
to his country, I was eager to record the opi¬
nion of so perfect and accomplished a judge on
a question which, for more than two centuries,
has divided the learned world; and which, his
profound admiration of Machiavel’s genius, com¬
bined with the most unqualified detestation of
Machiavel’s principles, had led him to study
with peculiar care. The letter is dated Pisa,
December 17. 1816.
- The united tribute of respect already paid by
Mr Horner’s political friends and his political
opponents, to his short but brilliant and spotless Notes
career in public life, renders all additional eulo- T„ and
. , . . Illustrations,
gies on his merits as a statesman, equally feeble
and superfluous. Of the extent and variety
of his learning, the depth and accuracy of his
scientific attainments, the classical (perhaps
somewhat severe) purity of his taste, and the
truly philosophical cast of his whole mind, none
had better opportunities than myself to form a
judgment, in the course of a friendship which
commenced before he left the University, and
which grew till the moment of his death. But
on these rare endowments of his understanding,
or the still rarer combination of virtues which
shed over all his mental gifts a characteristi-
cal grace and a moral harmony, this is not the
proper place to enlarge. Never certainly was
more completely realized the ideal portrait so
nobly imagined by the Roman poet: “ A calm
devotion to reason and justice, the sanctuary of
the heart undefiled, and a breast glowing with
inborn honour.”
Compositum jus fasque animo, sanctosque recessus
Mentis, et incoctum generoso pectus honesto.
Note D, p. 27.
The charge of plagiarism from Bodin has been
urged somewhat indelicately against Montes¬
quieu, by a very respectable writer, the Cheva¬
lier de Filangieri. “ On a cru, et 1’on croit
peut-etre encore, que Montesquieu a parle le
premier de I’influence du climat. Cette opinion
est une erreur. Avant lui, le delicat et inge-
nieux Fontenelle s’etoit exerce sur cet objet.
Machiavel, en plusieurs endroits de ses ouvrages,
parle aussi de cette influence du climat sur le
physique et sur le moral des peuples. Chardin,
un de ces voyageurs qui savent observer, a fai*
beaucoup de reflexions sur I’influence physique
et moral des climats. L’Abbe Dubos a soutenu
et developpe les pensees de Chardin ; et Bodin,
qui peut-etre avoit lu dans Polybe que In climat
determine les formes, la couleur, et les moeurs
des peuples, en avoit deja fait, cent cinquante
ans auparavant, la base de son systeme, dans
son livre de la Republique, et dans sa Methode
de 1’Histoire. Avant tous ces ecrivains, I’im-
mortel Hippocrate avoit traite fort au long cette
238
PRELIMINARY DISSERTATIONS.
Notes matiere dans son fameux ouvrage de Vair, des
®nd+. mux, et des lieux. L’auteur de 1’Esprit des Lois,
sans citer un seul de ces philosopnes, etablit a
son tour un systeme; mais il ne fit qu’alterer
les principes d’Hippocrate, et donner une plus
grande extension aux idees de Dubos, de Chardin,
et de Bodin. II voulut faire croire au public
qu’il avoit eu le premier quelques idees sur ce
sujet; et le public 1’en crut sur sa parole.”—La
Science de la Legislation, ouvrage traduit de Vita-
lien. Paris, 1786. Tom. I. pp. 225, 226.
The enumeration here given of writers whose
works are in every body’s hands, might have
satisfied Filangieri, that, in giving his sanction
to this old theory, Montesquieu had no wish to
claim to himself the praise of originality. It is
surprising, that, in the foregoing list, the name
of Plato should have been omitted, who concludes
his fifth book, De Legibus, with remarking, that
“ all countries are not equally susceptible of the
same sort of discipline; and that a wise legisla¬
tor will pay a due regard to the diversity of na¬
tional character, arising from the influence of
climate and of soil.” It is not less surprising,
that the name of Charron should have been over¬
looked, whose observations on the moral influ¬
ence of physical causes discover as much ori¬
ginality of thought as those of any of his succes¬
sors.—See De la Sagesse, Livre i. chap, xxxvii.
/
Note E, p. 29.
Innumerable instances of Luther’s credulity
and superstition are to be found in a book en¬
titled Martini Lutheri Colloquia Mensalia, fyc.
first published, according to Bayle, in 1571.
The only copy of it which I have seen, is a trans¬
lation from the German into the English tongue
by Captain Henrie Bell. (London 1652.) This
work, in which are <£ gathered up the fragments
of the divine discourses which Luther held at
his table with Philip Melanchthon, and divers
other learned men,” bears to have been origi¬
nally collected “ out of his holy mouth” by Dr
Anthony Lauterbach, and to have been after¬
wards c< digested into common-places” by Dr
Aurifaber. Although not sanctioned with Lu¬
ther’s name, I do not know that the slightest
doubts of its details have been suggested, even
by such of his followers as have regretted the Notes
indiscreet communication to the public, of his illusions
unreserved table-talk with his confidential com-
panions. The very accurate SeckendorfF has
not called in question its authenticity; but on
the contrary, gives it his indirect sanction, by
remarking, that it was collected with little pru¬
dence, and not less imprudently printed : “ Libro
Colloquiorum Mensalium minus quidem caute
composite et vulgato.” (Bayle, article Luther,
Note L.) It is very often quoted as an autho¬
rity by the candid and judicious Dr Jortin.
In confirmation of what I have said of Luther’s
credulity, I shall transcribe, in the words of the
English translator, the substance of one of
Luther’s Divine Discourses, “ concerning the
devil and his works.” “ The devil (said Lu¬
ther) can transform himself into the shape of a
man or a woman, and so deceiveth people; in¬
somuch that one thinketh he lieth by a right
woman, and yet is no such matter; for, as St
Paul saith, the devil is strong by the child of
unbelief. But inasmuch as children or devils
are conceived in such sort, the same are very
horrible and fearful examples. Like unto this
it is also with what they call the Nix in the wa¬
ter, who draweth people unto him as maids and
virgins, of whom he begetteth devils’ children.
The devil can also steal children away; as
sometimes children within the space of six weeks
after their birth are lost, and other children,
called supposititii, or changelings, laid in their
places. Of the Saxons they were called Kill-
crops.
“ Eight years since,” said Luther, {C at Des¬
sau, I did see and touch such a changed child,
which was twelve years of age; he had his eyes,
and all members, like another child; he did no¬
thing but feed, and would eat as much as two
clowns were able to eat. I told the Prince of
Anhalt, if I were prince of that country, I would
venture homicidium thereon, and would throw it
into the river Moldaw. I admonished the people
dwelling in that place devoutly to pray to God
to take away the devil. The same was done ac¬
cordingly, and the second year after the change ¬
ling died.
“ In Saxony, near unto Halberstad, was a
man that also had a killcrop, who sucked the
DISSERTATION FIRST.
239
Notes mother and five other women dry, and besides
illustrations, devoured very much. This man was advised
that he should, in his pilgrimage at Halberstad,
make a promise of the killcrop to the Virgin
Marie, and should cause him there to be rocked.
This advice the man followed, and carried the
changeling thither in a basket. But going over
a river, being upon the bridge, another devil
that was below in the river, called and said,
Killcrop ! killcrop ! Then the child in the bas¬
ket (which never before spoke one word), an¬
swered, Ho, ho. The devil in the water asked
further, Whither art thou going ? The child in
the basket said, I am going towards Hocklestad
to our loving mother, to he rocked. The man
being much affrighted thereat, threw the child,
with the basket, over the bridge into the water.
Whereupon the two devils flew away together,
and cried Ho, ho, ha, tumbling themselves over
one another, and so vanished.”—(pp. 386, 387.)
With respect to Luther’s Theological Disputes
with the Devil, see the passages quoted by Bayle,
Art. Luther, Note U.
Facts of this sort, so recent in their date, and
connected with the history of so great a charac¬
ter, are consolatory to those who, amid the fol¬
lies and extravagancies of their contemporaries,
are sometimes tempted to despair of the cause
of truth, and of the gradual progress of human
reason.
Note F, p. 38.
Ben Jonson is one of the few contemporary
writers by whom the transcendant genius of Ba¬
con appears to have been justly appreciated;
and the only one I know of, who has transmit¬
ted any idea of his forensic eloquence; a subject
on which, from his own professional pursuits,
combined with the reflecting and philosophical
cast of his mind, Jonson was peculiarly qualified
to form a competent judgment. cc There hap¬
pened,” says he, “ in my time, one noble speak¬
er, who was full of gravity in his speaking. No
man ever spoke more neatly, more pressly, more Notes
weightily, or suffered less emptiness, lest idle- *nd
ness in what he uttered. No member of his
speech hut consisted of its own graces. His
hearers could not cough, or look aside from him,
without loss. He commanded where he spoke,
and had his judges angry and pleased at his de¬
votion. The fear of every man that heard him
was, that he should make an end.” No finer
description of the perfection of this art is to be
found in any author, ancient or modern.
The admiration of Jonson for Bacon (whom
he appears to have known intimately1) seems
almost to have blinded him to those indelible
shades in his fame, to which, even at this dis¬
tance of time, it is impossible to turn the eye
without feelings of sorrow and humiliation.
Yet it is but candid to conclude, from the post¬
humous praise lavished on him by Jonson and
by Sir Kenelm Digby,2 3 that the servility of the
courtier, and the laxity of the judge, were, in
the relations of private life, redeemed by many
estimable and amiable qualities. That man
must surely have been marked by some rare fea¬
tures of moral as well as of intellectual great¬
ness, of whom, long after his death, Jonson
could write in the following words :
“ My conceit of his person was never increas¬
ed toward him by his place or honours; hut I
have and do reverence him, for the greatness
that was only proper to himself, in that he
seemed to me ever, by his works, one of the
greatest men, and most worthy of admiration,
that had been in many ages. In his adversity,
I ever prayed that God would give him strength,
for greatness he could not want. Neither could
I condole in a word or syllable for him, as know¬
ing no accident could do harm to virtue, but
rather help to make it manifest.”
In Aubrey’s anecdotes of Bacon,9 there are
several particulars not unworthy of the atten¬
tion of his future biographers. One expression
of this writer is more peculiarly striking: “ In
short, all that were great and good loved and
1 Jonson is said to have translated into Latin great part of the books De Augmentis Scientiarum. Dr Warton states
this (I do not know on what authority) as an undoubted fact. Essay on the Genius and Writings of Pope.
8 See his letters to M. de Fermat, printed at the end of Fermat’s Opera Mathematical Tolosae, 1679.
3 Lately published in the extracts from the Bodleian library.
240
PRELIMINARY DISSERTATIONS.
Notes honoured him.” When it is considered, that
Illustrations Aubrey’s knowledge of Bacon was derived chief-
ly through the medium of Hobbes, who had
lived in habits of the most intimate friendship
with both, and whose writings shew that he was
far from being an idolatrous admirer of Bacon’s
philosophy, it seems impossible for a candid
mind, after reading the foregoing short but com-
prehensive eulogy, not to feel a strong inclina¬
tion to dwell rather on the fair than on the dark
side of the Chancellor’s character, and, before
pronouncing an unqualified condemnation, care¬
fully to separate the faults of the age from those
of the individual.
An affecting allusion of his own, in one of his
greatest works, to the errors and misfortunes of
his public life, if it does not atone for his faults,
may, at least, have some effect in softening the
asperity of our censures. <c Ad literas potius
quam ad aliud quicquam natus, et ad res ge-
rendas nescio quo fato contra genium suum ab-
reptus.”—De Aug. Scient. L. viii. c. iii.
Even in Bacon’s professional line, it is now
admitted, by the best judges, that he was great¬
ly underrated by his contemporaries. “ The
Queen did acknowledge,” says the Earl of Es¬
sex, in a letter to Bacon himself, “ you had a
great wit, and an excellent gift of speech, and
much other good learning. But in law, she ra¬
ther thought you could make shew, to the utmost
of your knowledge, than that you were deep.”
“ If it be asked,” says Dr Hurd, “ how the
Queen came to form this conclusion, the answer
is plain. It was from Mr Bacon’s having a
great wit, an excellent gift of speech, and much
other good learning.”—(Hurd’s Dialogues.)
The following testimony to Bacon’s legal
knowledge (pointed out to me by a learned
friend) is of somewhat more weight than Queen
Elizabeth’s judgment against it: <£ What might
we not have expected,” says Mr Hargrave, af¬
ter a high encomium on the powers displayed
by Bacon in his ‘ Reading on the Statute of Uses ;’
“ what might we not have expected from the
hands of such a master, if his vast mind had not
so embraced within its compass the whole field
of science, as very much to detach him from
professional studies !?>
It was probably owing in part to his court-
disgrace, that so little notice was taken of Ba- Notes
con, for some time after his death, by those Eng- iiius^ad.ioni
lish writers who availed themselves, without
any scruple, of the lights struck out in his
works. A very remarkable example of this oc¬
curs in a curious, though now almost forgotten
hook (published in 1627), entitled, An Apology
or Declaration of the Power and Providence of
God in the Government of the World, by George
Hakewill, D. D. Archdeacon of Surrey. It is
plainly the production of an uncommonly liberal
and enlightened mind; well stored with various
and choice learning, collected both from ancient
and modern authors. Its general aim may he
guessed at from the text of Scripture prefixed to
it as a motto, “ Say not thou, what is the cause
that the former days are better than these, for
thou dost not inquire wisely concerning this
and from the words of Ovid, so happily applied
by Hakewill to the “ common error touching
the golden age,”
Prisca juvent alios, ego me nunc denique natum
Gratulor.
That the general design of the hook, as well
as many incidental observations contained in it,
was borrowed from Bacon, there cannot, I ap¬
prehend, be a doubt; and yet I do not recollect
more than one or two references (and these very
slight ones) to his writings, through the whole
volume. One would naturally have expected,
that, in the following passage of the epistle de¬
dicatory, the name of the late unfortunate Chan¬
cellor of England, who had died in the course
of the preceding year, might have found a place
along with the other great clerks there enume¬
rated : <£ I do not believe that all regions of the
world, or all ages in the same region, afford
wits always alike; but this I think (neither is
it my opinion alone, but of Scaliger, Yives, Bu-
dseus, Bodin, and other great clerks), that the
wits of these latter ages, being manured by in¬
dustry, directed by precepts, and regulated by
method, may be as capable of deep speculations,
and produce as masculine and lasting births, as
any of the ancienter times have done. But if
we conceive them to be giants, and ourselves
dwarfs; if we imagine all sciences already to
have received their utmost perfection, so as we
need not but translate and comment on what
DISSERTATION FIRST.
241
Notes they have done, surely there is little hope that
Illustrations.we should ever come near them, much less
match them. The first step to enable a man to
the achieving of great designs, is to be persuad¬
ed that he is able to achieve them ; the next
not to be persuaded, that whatsoever hath not
yet been done, cannot therefore be done. Not
any one man, or nation, or age, but rather
mankind is it, which, in latitude of capacity,
answers to the universality of things to be
known.” In another passage, Hakewill ob¬
serves, that, “ if we will speak properly and
punctually, antiquity rather consists in old age,
than in the infancy or youth of the world.” I
need scarcely add, that some of the foregoing
sentences are almost literal transcripts of Bacon’s
words.
The philosophical fame of Bacon in his own
country may be dated from the establishment of
the Royal Society of London; by the founders
of which, as appears from their colleague, Dr
Sprat, he was held in so high estimation, that
it was once proposed to prefix to the history of
their labours some of Bacon’s writings, as the
best comment on the views with which they
were undertaken. Sprat himself, and his illus¬
trious friend Cowley, were among the number
of Bacon’s earliest eulogists; the latter in an
Ode to the Royal Society, too well known to
require any notice here; the former in a very
splendid passage of his History, from which I
shall borrow a few sentences, as a conclusion
and ornament to this note.
“ For, is it not wonderful, that he who had
run through all the degrees of that profession,
which usually takes up men’s whole time; who
had studied, and practised, and governed the
common law; who had always lived in the
crowd, and borne the greatest burden of civil
business; should yet find leisure enough for
these retired studies, to excel all those men,
who separate themselves for this very purpose?
He was a man of strong, clear, and powerful
imaginations; his genius was searching and in¬
imitable ; and of this I need give no other proof
than his style itself; which as, for the most
part, it describes men’s minds, as well as pic- Notes
tures do their bodies, so it did his above all T„ and
i„ . Illustrations,
men living. 1 he course of it vigorous and ma-
jestical; the wit bold and familiar ; the compa¬
risons fetched out of the way, and yet the more
easy:1 In all expressing a soul equally skilled
in men and nature.”
Note G, p. 40.
The paradoxical bias of Hobbes’s understand¬
ing is never so conspicuous as when he engages
in physical or in mathematical discussions. On
such occasions, he expresses himself with even
more than his usual confidence and arrogance.
Of the Royal Society f the Virtuosi, as he calls
them, that meet at Gresham College) he writes
thus: “ Conveniant, studia conferant, experi-
menta faciant quantum volunt, nisi et principiis
utantur meis, nihil proficient.” And elsewhere:
“ Ad causas autem propter quas proficere ne
paullum quidem potuistis nec poteritis, acce-
dunt etiam alia, ut odium Hobbii, quia nimium
libere scripserat de academiis veritatem : Nam
ex eo tempore irati physici et mathematici veri¬
tatem ab eo venientem non recepturos se palam
professi sunt.” In bis English publications, he
indulges in a vein of coarse scurrility, of which
his own words alone can convey any idea.
“ So go your ways,” says he, addressing him¬
self to Dr Wallis and Dr Seth Ward, two of
the most eminent mathematicians then in Eng¬
land, “ you uncivil ecclesiastics, inhuman di¬
vines, de-doctors of morality, unasinous col¬
leagues, egregious pair of Issachars, most
wretched indices and vindices academiarum; and
remember Vespasian’s law, that it is unlawful to
give ill language first, but civil and lawful to re¬
turn it.”
Note H. p. 42.
With respect to the Leviathan, a very curious
anecdote is mentioned by Lord Clarendon.
“ When I returned,” says he, C{ from Spain by
Paris, Mr Hobbes frequently came to me, and
the word easy, I presume Sprat here means the native and spontaneous growth of Bacon’s own fancy, in opposi¬
tion to the traditionary similes borrowed by common-place writers from their predecessors.
DISS. I. PART II. 2 H
242
preliminary dissertations.
Notes told me that liis book, which he would call Le-
viathan, was then printing in England, and that
he received every week a sheet to correct; ana
thought it would he finished within a little more
than a month. He added, that he knew when I
read the hook I would not like it; and theie-
upon mentioned some conclusions; upon which I
asked him why he would publish such doctiines;
to which, after a discourse between jest and ear¬
nest, he said, ‘ The truth is, I have a mind to go
home.'’ ” In another passage, the same writer ex¬
presses himself thus:—“ The review and con¬
clusion of the Leviathan is, in truth, a sly ad¬
dress to Cromwell, that, being out of the king¬
dom, and so being neither conquered nor his
subject, he might, by his return, submit to his
government, and he bound to obey it. This re-
, view and conclusion he made short enough to
hope that Cromwell might read it; where he
should not only receive the pawn of his new
subject’s allegiance, by declaring his own obli¬
gations and obedience; but by publishing such
doctrines as, being diligently infused by such a
master in the art of government, might secure
the people of the kingdom (over whom he had
no right to command) to acquiesce and submit
to his brutal power.”
That there is no exaggeration or misrepresen¬
tation of facts in these passages, with the view
of injuring the character of Hobbes, may be
confidently presumed from the very honourable
testimony which Clarendon bears, in another
part of the same work, to his moral as well as
intellectual merits. “ Mr Hobbes,” he observes,
“ is a man of excellent parts; of great wit; of
some reading; and of somewhat more thinking;
one who has spent many years in foreign parts
and observations; understands the learned as
well as modern languages; hath long had the
reputation of a great philosopher and mathema¬
tician; and in his age hath had conversation
with many worthy and extraordinary men. In
a word, he is one of the most ancient acquain¬
tance I have in the world, and of whom I have Notes
always had a great esteem, as a man, who, be- i]i„strations<
sides his eminent learning and knowledge, hath
been always looked upon as a man of probity,
and of a life free from scandal.”
Note I, p. 58.
It is not easy to conceive how Descartes re¬
conciled, to his own satisfaction, his frequent
use of the word substance, as applied to the mind,
with his favourite doctrine, that the essence of
the mind consists in thought. Nothing can he
well imagined more unphilosophical than this
last doctrine, in whatever terms it is expressed;
but to designate by the name of substance, what
is also called thought, in the course of the same
argument, renders the absurdity still more gla¬
ring than it would otherwise have been.
I have alluded, in the text, to the difference
between the popular and the scholastic notion
of substance. According to the latter, the word
substance corresponds to the Greek word ouova, as
employed by Aristotle to denote the first of the
predicaments; in which technical sense it is
said, in the language of the schools, to signify
that which supports attributes, or which is sub¬
ject to accidents. At a period when every person
liberally educated was accustomed to this bar¬
barous jargon, it might not appear altogether
absurd to apply the term substance to the human
soul, or even to the Deity. But, in the present
times, a writer who so employs it may be as¬
sured, that, to a great majority of his readers, it
will be no less puzzling than it was to Crambe,
in Martinus Scriblerus, when he first heard it
thus defined by his master Cornelius.1 How
extraordinary does the following sentence now
sound even to a philosophical ear ? and yet it is
copied from a work published little more than
seventy years ago, by the learned and judicious
Gravesande: Substantiae sunt aut cogitantes,
aut non cogitantes; cogitantes duas novimus,
1 “ When he was told, a substance was that which was subject to accidents, then soldiers, quoth Cramhe, are the most sub¬
stantial people in the world.” Let me add, that, in the list of philosophical reformers, the authors of Martinus Scriblerus
ought not to be overlooked. Their happy ridicule of the scholastic Logic and Metaphysics is universally known ; but few
are aware of the acuteness and sagacity displayed in their allusions to some of the most vulnerable passages in Locke’s
Essav. In this part of the work it is commonly understood that Arbuthnot had the principal share.
DISSERTATION FIRST.
243
Notes Deum et mentem nostram. Duae etiam sub-
niustradons. stantise’ (lUOe 11011 cogitant> nobis notSB Slintj
spatium et corpus.”—Introd. ad Phil. § 19
The Greek word dxua (derived from the parti¬
ciple of e//w) is not liable to these objections. It
obtrudes no sensible image on the fancy; and,
in this respect, has a great advantage over the
Latin word substantia. The former, in its logical
acceptation, is an extension to Matter, of an idea
originally derived from Mind. The latter is an
extension to Mind of an idea originally derived
from Matter.
Instead of defining mind to he a thinking sub-
stance, it seems much more logically correct to
define it a thinking being. Perhaps it would he
better still, to avoid, by the use of the pronoun
that, any substantive whatever, Ci Mind is that
which thinks, wills,” &c.
The foregoing remarks afford me an opportu¬
nity of exemplifying what I have elsewhere
observed concerning the effects which the scho¬
lastic philosophy has left on the present habits of
thinking, even of those who never cultivated that
branch of learning. In consequence of the stress
laid on the predicaments, men became accustom¬
ed in their youth to imagine, that in order to
know the nature of any thing, it was sufficient
to know under what predicament or category it
ought to be arranged; and that, till this was
done, it remained to our faculties a subject mere¬
ly of ignorant wonder. Hence the impotent
attempt to comprehend under some common
name (such as that of substance) the heterogene¬
ous existences of matter, of mind, and even of
empty space ; and hence the endless disputes to
which the last of these words has given rise in
the Schools.
In our own times, Kant and his followers
seem to have thought, that they had thrown a
new and strong light on the nature of space and
also of time, when they introduced the word
form (forms of the intellect) as a common term
applicable to both. Is not this to revert to the
scholastic folly of verbal generalization ? And
is it not evident, that of things which are unique
(such as matter, mind, space, time) no classifica¬
tion is practicable ? Indeed to speak of classi¬
fying what has nothing in common with any
thing else, is a contradiction in terms. It was Notes
thus that St Augustine felt, when he said, “ Quid uiu^rnal|ions
sit tempus, si nemo quaerat a me, scio; si quis
interroget, nescio.” His idea evidently was,
that, although he annexed as clear and precise a
notion to the word time, as he could do to any ob¬
ject of human thought, he was unable to find
any term more general, under which it could be
comprehended; and, consequently, unable to
give any definition, by which it might be ex¬
plained.
Note K, p. 58.
“ Les Meditations de Descartes parurent en
1641. C’etoit, de tous ses ouvrages, celui qu’il
estimoit le plus. Ce qui characterise sur tout
cet ouvrage, c’est qu’il contient sa fameuse de¬
monstration de Dieu par 1’idee, demonstration si
repetee depuis, adoptee par les unes, et rejettee
par les autres; et qu’il est le premier ou la distinc¬
tion de Vesprit et de la matiere soil parfaitement
dheloppee, car avant Descartes on n’avoit encore
bien approfondi les preuves philosopbiques de la
spiritualite de Tame.”—Eloge de Descartes, par
M. Thomas. Note 20.
If the remarks in the text be correct, the cha-
racteristical merits of Descartes’ Meditations do
not consist in the novelty of the proofs contained
in them of the spirituality of the soul (on which
point Descartes has added little or nothing to
what had been advanced by his predecessors),
but in the clear and decisive arguments by which
they expose the absurdity of attempting to ex¬
plain the mental phenomena, by analogies bor¬
rowed from those of matter. Of this distinction,
neither Thomas, nor Turgot, nor D’Alembert,
nor Condorcet, seem to have been at all aware.
I quote from the last of these writers an ad¬
ditional proof of the confusion of ideas upon this
point, still prevalent among the most acute lo¬
gicians. “ Ainsi la spiritualite de Vdme, n’est
pas une opinion qui ait besoin de preuves, mais
le resultat simple et naturel d’un analyse exacte
de nos idees, et de nos facultes.”—(Vie de M.
Turgot.) Substitute for spirituality the word
immateriality, and the observation becomes equal¬
ly just and important.
244
PRELIMINARY DISSERTATIONS.
Notes
and
Illustrations.
Note L, p. 59.
The following extract from Descartes might
be easily mistaken for a passage in the Novum
Organon.
ce Quoniam infantes nati sumus, et varia de
rebus sensibilihus judicia prius tulimus, quam
integrum nostrse ratioms usum hahexemusj mul-
tis prsejudiciis a veri cognitione avertimur, qui-
bus non aliter videmur posse liberari, quam si
semel in vita, de iis omnibus studeamus dubitare,
in quibus vel minimamincertitudinis suspicionem
reperiemus.
“ Quin et ilia etiam, de quibus dubitabimus,
utile erit habere pro falsis, ut tanto clarius, quid-
nam certissimum et cognitu facillimum sit, in-
veniamus.
“ Itaque ad serio philosophandum, veritatem-
que omnium rerum cognoscibilium indagandam,
primo omnia prsejudicia sunt deponenda; sive
accurate est cavendum, ne ullis ex opinionibus
olim a nobis receptis fidem habeamus, nisi prius,
iis ad novum examen revocatis, veras esse com-
pcriamus.”—Princ. Phil Pars Prima, §§ lii. Ixxv.
Notwithstanding these and various other si¬
milar coincidences, it has been asserted with
some confidence, that Descartes had never read
the works of Bacon. “ Quelques auteurs as-
surent que Descartes n’avoit point lu les ouvrages
de Bacon ; et il nous dit lui-meme dans une de
ses letters, qu’il ne lut que fort tard les prin-
cipaux ouvrages de Galilee.”—[Ploge de Des¬
cartes, par Thomas.) Of the veracity of Des¬
cartes I have not the slightest doubt; and there¬
fore I consider this last fact (however extraor¬
dinary) as completely established by his own
testimony. But it would require more evidence
than the assertions of those nameless writers al-
1 uded to by Thomas, to convince me that he had
never looked into an author, so highly extolled
as Bacon is, in the letters addressed to himself
by his illustrious antagonist, Gassendi. At any
rate, if this was actually the case, I cannot sub¬
scribe to the reflection subjoined to the fore¬
going quotation by his eloquent eulogist: “Si
cela est, il faut convenir, que la gloire de Des¬
cartes en est bien plus grande.”
Note M, p. 65. ^otes
r and
Illustrations.
From the indissoluble union between the no-
tions of colour and extension, Dr Berkeley has
drawn a curious, and, in my opinion, most il¬
logical argument in favour of his scheme of ideal¬
ism ;—which, as it may throw some additional
light on the phenomena in question, I shan trans¬
cribe in his own words.
“ Perhaps, upon a strict inquiry, we shall
not find, that even those who, from their birth,
have grown up in a continued habit of seeing,
are still irrevocably prejudiced on the other side,
to wit, in thinking what they see to be at a dis¬
tance from them. For, at this time, it seems
agreed on all hands, that colours, which are the
proper and immediate objects of sight, are not
without the mind. But then, it will be said, by
sight we have also the ideas of extension, and
figure, and motion; all which may well be
thought without, and at some distance from the
mind, though colour should not. In answer to
this, I appeal to any man’s experience, whether
the visible extension of any object doth not ap¬
pear as near to him as the colour of that object;
nay, whether they do not both seem to be in the
same place. Is not the extension we see co¬
loured ; and is it possible for us, so much as
in thought, to separate and abstract colour from
extension ? Now, where the extension is, there
surely is the figure, and there the motion too.
I speak of those which are perceived by sight.”1
Among the multitude of arguments advanced
by Berkeley, in support of his favourite theory,
I do not recollect any that strikes me more with
the appearance of a wilful sophism than the
foregoing. It is difficult to conceive how so
very acute a reasoner should not have perceived
that his premises, in this instance, lead to a con¬
clusion directly opposite to what he has drawn
from them. Supposing all mankind to have an
irresistible conviction of the outness and distance
of extension and figure, it is very easy to explain,
from the association of ideas, and from our early
habits of inattention to the phenomena of con¬
sciousness, how the sensations of colour should
appear to the imagination to be transported
1 Essay toward a New Theory of Vision, p. 255.
DISSERTATION FIRST.
245
Notes out of the mind. But if, according to Berkeley’s
Illustrations, doctrines, the constitution of human nature
—leads men to believe that extension and figure,
and every other quality of the material universe,
exists only within themselves, whence the ideas
of external and of internal; of remote or of near ?
When Berkeley says, “ I appeal to any man’s
experience, whether the visible extension of any
object doth not appear as near to him as the
colour of that objecthow much more reason¬
able would it have been to have stated the in¬
disputable fact, that the colour of the object ap¬
pears as remote as its extension and figure ? No¬
thing, in my opinion, can afford a more conclu¬
sive proof, that the natural judgment of the
mind is against the inference just quoted from
Berkeley, than the problem of D’Alembert,
which has given occasion to this discussion.
Note N, p. 68.
It is observed by Dr Reid, that “ the system
which is now generally*received with regard to
the mind and its operations, derives not only its
spirit from Descartes, but its fundamental prin¬
ciples; and that, after all the improvements
made by Malebranche, Locke, Berkeley, and
Hume, it may still be called the Cartesian sys¬
tem.”—Conclusion of the Inquiry into the Human
Mind.
The part of the Cartesian system here alluded
to is the hypothesis, that the communication be¬
tween the mind and external objeets is carried
on by means of ideas or images;—not, indeed,
transmitted from without (as the Aristotelians
supposed) through the channel of the senses,
but nevertheless bearing a relation to the quali¬
ties perceived, analogous to that of an impres¬
sion on wax to the seal by which it was stamp¬
ed. In this last assumption, Aristotle and Des¬
cartes agreed perfectly; and the chief differ¬
ence between them was, that Descartes palliat¬
ed, or rather kept out of view, the more obvious
absurdities of the old theory, by rejecting the
unintelligible supposition of intentional species,
and by substituting, instead of the word image,
the more indefinite and ambiguous word idea.
But there was another and very important
step made by Descartes, in restricting the ideal
Theory to the primary qualities of matter; its Notes
secondary qualities (of colour, sound, smell, lllu^atinls.
taste, heat, and cold) having, according to him,
no more resemblance to the sensations by means
of which they are perceived, than arbitrary
sounds have to the things they denote, or the
edge of a sword to the pain it may occasion.
(Princ. Pars iv. §§ 197, 198.) To this doc¬
trine he frequently recurs in other parts of his
works.
In these modifications of the Aristotelian
Theory of Perception, Locke acquiesced entire¬
ly ; explicitly asserting, that “ the ideas of pri¬
mary qualities are resemblances of them, but
that the ideas of secondary qualities have no re¬
semblance to them at all.” —Essay, B. ii. c.
viii. § 15.
When pressed by Gassendi to explain how
images of extension and figure can exist in an
unextended mind, Descartes expresses himself
thus: 11 Quseris quomodo existimem in me sub-
jecto inextenso recipi posse speciem ideamve
corporis quod extensum est. Respondeo nullum
speciem corpoream in mente recipi, sed puram
intellectionem tarn rei corporeae quam incorpo-
rese fieri absque ulla specie corporese; ad ima-
ginationem vero, quae non nisi de rebus corpo-
reis esse potest, opus quidem esse specie quae
sit verum corpus, et ad quam mens se applied
sed non quae in mente recipiatur.” Besponsio
de Us quee in sextam Meditationem objecta
sunh § 4.
In this reply it is manifestly assumed as an
indisputable principle, that the immediate ob¬
jects of our thoughts, when we imagine or con¬
ceive the primary qualities of extension and
figure, are ideas or species of these qualities;
and, of consequence, are themselves extended
and figured. Had it only occurred to him to
apply (mutatis mutandis) to the perception of
primary qualities, his own account of the per¬
ception of secondary qualities (that it is obtain¬
ed, to wit, by the media of sensations more ana¬
logous to arbitrary signs, than to stamps or
pictures), he might have eluded the difficulty
started by Gassendi, without being reduced to
the disagreeable necessity of supposing his ideas
or images to exist in the brain, and not in the
mind. The language of Mr Locke, it is oh-
246
PRELIMINARY DISSERTATIONS.
Notes servable, sometimes implies the one of these
illustrations, hypotheses, and sometimes the other.
It was plainly with the view of escaping from
the dilemma proposed by Gassendi to Descartes,
that Newton and Clarke were led to adopt a
mode of speaking concerning perception, ap¬
proaching very nearly to the language of Des¬
cartes. “ Is not,” says Newton, “ the senso-
rium of animals the place where the sentient
substance is present; and to which the sensible
species of things are brought, through the nerves
and brain, that there they may be perceived by
the mind present in that place ?” And still more
confidently Dr Clarke: “ Without being pre¬
sent to the images of the things perceived, the
soul could not possibly perceive them. A liv¬
ing substance can only there perceive where it
is present. Nothing can any more act or be
acted upon where it is not present, than it can
when it is not.” The distinction between pri¬
mary and secondary qualities was afterwards re¬
jected by Berkeley, in the course of his argu¬
ment against the existence of matter; but he
continued to retain the language of Descartes
concerning ideas, and to consider them as the
immediate, or rather as the only objects of our
thoughts, wherever the external senses are con¬
cerned. Mr Hume’s notions and expressions
on the subject are very nearly the same.
I thought it necessary to enter into these
details, in order to show with what limitations
the remark quoted from Dr Reid in the be¬
ginning of this note ought to be received. It
is certainly true, that the Cartesian system may
be said to form the groundwork of Locke’s
Theory of Perception, as well as of the scepti¬
cal conclusions deduced from it by Berkeley
and Hume; but it is not the less true, that it
forms also the groundwork of all that has since
been done towards the substitution, in place of
his scepticism, of a more solid fabric of meta¬
physical science.
Note O, p. 69.
After the pains taken by Descartes to ascer¬
tain the seat of the soul, it is surprising to find
one of the most learned English divines of the
seventeenth century (Dr Henry More) accusing
him as an abettor of the dangerous heresy of
nullibism. Of this heresy Dr More represents
Descartes as the chief author; and, at the same
time, speaks of it as so completely extravagant,
that he is at a loss whether to treat it as the se¬
rious opinion of the philosopher, or as the jest of
a buffoon. “ The chief author and leader of
the Nullibists,” he tells us, “ seems to have
been that pleasant wit, Renatus Descartes, who,
by his jocular metaphysical meditations, has
luxated and distorted the rational faculties of
some otherwise sober and quick-witted persons/’
To those who are at all acquainted with the phi¬
losophy of Descartes, it is unnecessary to ob¬
serve, that, so far from being a Nullibist, he
valued himself not a little on having fixed the
precise uhi of the soul, with a degree of accu¬
racy unthought of by any of his predecessors.
As he held, however, that the soul was unextend¬
ed, and as More happened to conceive that no¬
thing which was unextended could have any re¬
ference to place, he seems to have thought him¬
self entitled to impute to Descartes, in direct
opposition to his own words, the latter of these
opinions as well as the former. “ The true no¬
tion of a spirit,” according to More, “ is that
of an extended penetrable substance, logically
and intellectually divisible, but not physically
discernible into parts.”
Whoever has the curiosity to look into the
works of this once admired, and, in truth, very
able logician, will easily discover that his alarm
at the philosophy of Descartes was really occa¬
sioned, not by the scheme of nullibism, but by
the Cartesian doctrine of the non-extension of
mind, which More thought inconsistent with a
fundamental article in his own creed—the ex¬
istence of witches and apparitions. To hint at
any doubt about either, or even to hold any
opinion that seemed to weaken their credibility,
appeared to this excellent person quite a suffi¬
cient proof of complete atheism.
The observations of More on “ the true no¬
tion of a spirit” (extracted from his Enchiridion
Ethicum) were afterwards republished in Glan-
ville’s book upon witchcraft;—a work (as I be¬
fore mentioned) proceeding from the same pen
Notes
and
Illustrations.
DISSERTATION FIRST.
247
Kotes
and
Fllustrations.
with the Scepsis Scientifica, one of the most
acute and original productions of which English
philosophy had then to boast.
If some of the foregoing particulars should, at
first sight, appear unworthy of attention in a
historical sketch of the progress of science, I
must beg leave to remind my readers, that they
belong to a history of still higher importance
and dignity—that of the progress of Reason,
and of the Human Mind.
Note P, p. 70.
and fancy, as well as of his classical taste. One Notes
of the most remarkable is a letter addressed to nius^lions.
Balzac, in which he gives his reasons for prefer-
ring Holland to all other countries, not only as
a tranquil, but as an agreeable residence for a
philosopher; and enters into some very enga¬
ging details concerning his own petty habits.
The praise bestowed on this letter by Thomas
is by no means extravagant, when he compares
it to the best of Balzac’s. “ Je ne s9ais s’il y a
rien dans tout Balzac ou il y ait autant d’esprit
et d’agrement.”
For an interesting sketch of the chief events
in the life of Descartes, see the Notes annexed
to his Eloge by Thomas; where also is to be
found a very pleasing and lively portrait of his
moral qualities. As for the distinguishing me¬
rits of the Cartesian philosophy, and more par¬
ticularly of the Cartesian metaphysics, it was a
subject peculiarly ill adapted to the pen of this
amiable and eloquent, but verbose and decla¬
matory academician.
I am doubtful, too, if Thomas has not gone
too far, in the following passage, on a subject
of which he was much more competent to judge
than of some others which he has ventured to
discuss. <c L’imagination brillante de Descartes
se decele partout dans ses ouvrages; et s’il
n’avoit voulu etre ni geometre ni philosophe, il
n’auroit tenu qu’a lui d’etre le plus bel esprit
de son temps.” Whatever opinion may be
formed on this last assertion, it will not be dis¬
puted by those who have studied Descartes, that
his philosophical style is remarkably dry, con¬
cise, and severe. Its great merit lies in its sin¬
gular precision and perspicuity;—a perspicuity,
however, which does not dispense with a mo¬
ment’s relaxation in the reader’s attention ; the
author seldom repeating his remarks, and hard¬
ly ever attempting to illustrate or to enforce
them either by reasoning or by examples. In
all these respects, his style forms a complete
contrast to that of Bacon’s.
In Descartes’ epistolary compositions, indeed,
ample evidences are to be found of his vivacity
Note Q, p. 73.
It is an error common to by far the greater
number of modern metaphysicians, to suppose
that there is no medium between the innate
ideas of Descartes, and the opposite theory of
Gassendi. In a very ingenious and learned es¬
say on Philosophical Prejudices, by M. Trem-
bley,1 I find the following sentence:—“ Mais
1’experience dement ce systeme des idees innees,
puisque la privation d’un sens emporte avec elle
la privation des idees attachees a ce sens, comme
l’a remarque I’illustre auteur de VEssai Analy-
tique sur les Facultes de V Ame.”
What are we to understand by the remark
here ascribed to Mr Bonnet? Does it mean
nothing more than this, that to a person born
blind, no instruction can convey an idea of co¬
lours, nor to a person born deaf, of sounds ? A
remark of this sort surely did not need to be
sanctioned by the united names of Bonnet and
of Trembley: Nor, indeed, does it bear in the
slightest degree on the point in dispute. The
question is not about our ideas of the material
world, but about those ideas on metaphysical and
moral subjects, which may be equally imparted to
the blind and to the deaf; enabling them to arrive
at the knowledge of the same truths, and exciting
in their minds the same moral emotions. The signs
employed in the reasonings of these two classes
of persons will of course excite by association,
in their respective fancies, very different mate¬
rial images; but whence the origin of the phy-
Essai sur les Prejuges, &c. Neuchatel, 1790.
248
PRELIMINARY DISSERTATIONS.
Notes sical and moral notions of which these signs are
Illustrations. t^ie vehicle, and for suggesting which, all sets
of signs seem to he equally fitted ? The asto¬
nishing scientific attainments of many persons,
blind from their birth, and the progress lately
made in the instruction of the deaf, furnish pal¬
pable and incontestible proofs of the flimsiness of
this article of the Epicurean philosophy;—so com¬
pletely verified is now the original and profound
conclusion long ago formed by Dalgarno, “ That
the soul can exert her powers by the ministry
of any of the senses: And, therefore, when she
is deprived of her principal secretaries, the eye
and the ear, then she must he contented with
the service of her lackeys and scullions, the
other senses; which are no less true and faithful
to their mistress than the eye and the ear; hut
not so quick for dispatch.”—(Didascalocophus,
&c. Oxford, 1680.)
I was once in hopes of being able to throw a
still stronger light on the subject of this note,
by attempting to ascertain experimentally the
possibility of awakening and cultivating the dor¬
mant powers of a boy destitute of the organs
both of sight and of hearing; hut unexpected
occurrences have disappointed my expectations.
I have just learned, that a case somewhat si¬
milar, though not quite so favourable in all its
circumstances, has recently occurred in the state
of Connecticut in New England; and I have the
satisfaction to add, there is some probability that
so rare an opportunity for philosophical observa¬
tions and experiments will not be overlooked in
that quarter of the world.
Note R, p. 74.
Of Gassendi’s orthodoxy as a Roman Catholic
divine, he has left a very curious memorial, in
an inaugural discourse pronounced in 1645, be¬
fore Cardinal Richelieu, when he entered on the
duties of his office as Regius Professor of Ma¬
thematics at Paris. The great object of the ora¬
tion is to apologise to his auditors for his having
abandoned his ecclesiastical functions, to teach
and cultivate the profane science of geometry.
, With this view, he proposes to explain and il¬
lustrate the saying of Plato, who, being ques¬
tioned about the emnloyment of the Supreme
Being, answered Ywnirguv rhv Qt-nv. In the prose- Notes
cution of this argument, he expresses himself
thus on the doctrine of the Trinity.
“ Anne proinde hoc adorandum Trinitatis
mysterium hahebimus rursus ut sphaeram, cujus
quasi centrum sit Pater iEternus, qui totius di-
vinitatis fons, origo, principium accommodate
dicitur; circumferentia Filius, in quo legitur
habitare plenitude Divinitatis; et radii centre
circumferentiseque intercedentes Spiritus Sanc-
tus, qui est Patris et Filii nexus, vinculumque
mutuum ? Anne potius dicendum est eminere
in hoc mysterio quicquid sublime magnificumque
humana geometria etiamnum requirit ? Perce-
lehre est latere earn adhuc, quam quadraturam
circuli vocant; atque idcirco in eo esse, ut de-
scrihat triangulum, cujus si basin ostenderit cir¬
culi amhitui sequalem, turn demum esse circulo
triangulum sequale demonstrat. At in hoc mys¬
terio augustissimo gloriosissima Personarum
Trias ita infinitse essentise, ipsiusque foecundi-
tati, tan quam circulo exequatur, seu, ut sic lo-
quar, et verius quidem, penitus identificatur;
ut cum sit omnium, et cuj usque una, atque
eadem essentia, una proinde ac eadem sit im-
mensitas, seternitas, et perfectionum plenitude.
“ Sic, cum nondum norit humana geometria
trisecare angulum, dividereve, etcitra accommo-
dationem mechanicam, ostendere divisum esse
in tria sequalia; hahemus in hocce mysterio unam
essentiam non tam trisectam, quam integram
communicatam in tria eequalia supposita, quae
cum simul, sigillatimque totam individuamque
possideant, sint inter se tamen realiter distincta.”
The rest of the oration is composed in exactly
the same taste.
The following interesting particulars of Gas¬
sendi’s death are recorded by Sorhiere.
“ Extremam tamen horam imminentem sen-
tiens, quod reliquum erat virium impendendum
existimavit praeparando ad mortem animo.
Itaque significavit, ut quamprimum vocaretur
Sacerdos, in cujus aurem, dum fari poterat,
peccata sua effunderet  Bein, ut
nihil perfectae Christian! militis armaturse deesset,
sacro inungi oleo efflagitavit. Ad quam csere-
moniam animo attendens, cum sacerdos aures
inungens pronuntiaret verba solennia, et lapsu
quodam memorise dixisset, Indulgeattibi Dominus
DISSERTATION FIRST.
249
Notes quidquid per odoratum peccasti, reposuit statim
[lustrations, ^mo Per auditum; adeo mtentus erat rei
gravissimse, et eluendarum sordium vel mini-
marum cupidum se et sitibundum gerebat.”
Sorberi Prcefatio.
Having mentioned in the text the avowed
partiality of Gassendi for the Epicurean ethics,
it is but justice to his memory to add, that his
own habits were, in every respect, the reverse of
those commonly imputed to this school. “ Ad
privatam Gassendi vitam ssepius attendens,”
says Sorhiere, “ anachoretam aliquem cernere
mihi videor, qui media in urhe vitam instituit
plane ad monachi severioris normam; adeo pau-
pertatem, castitatem et obedientiam coluit; quan-
quam sine ullo voto tria ista vota solvisse videa-
tur.——Abstemius erat sponte sua, ptisanam
tepidam bibens pulmoni refrigerando humectan-
doque. Carne raro, herbis seepius, ac macerata
offa mane et vespere utebatur.”—Ibid.
Note S, p. 105.
It deserves to be remarked, as a circumstance
which throws considerable light on the literary
history of Scotland during the latter half of the
eighteenth century, that, from time immemorial,
a continued intercourse had been kept up be¬
tween Scotland and the Continent. To all who
were destined for the profession of law, an edu¬
cation either at a Dutch or French university
was considered as almost essential. The case
was nearly the same in the profession of physic;
and, even among the Scottish clergy, I have
conversed, in my youth, with some old men who
had studied theology in Holland or in Germany.
Of our smaller country gentlemen, resident on
their own estates (an order of men which, from
various causes, has now, alas ! totally vanished),
there was scarcely one who had not enjoyed the Notes
benefit of a university education; and very fewestrationg
of those who could alford the expence of foreign
travel, who had not visited France and Italy.
Lord Monboddo somewhere mentions, to the
honour of his father, that he sold part of his
estate to enable himself (his eldest son) to pursue
his studies at the University of Groningen.
The constant influx of information and of libera¬
lity from abroad, which was thus kept up in
Scotland in consequence of the ancient habits
and manners of the people, may help to account
for the sudden burst of genius, which to a
foreigner must seem to have sprung up in this
country by a sort of enchantment, soon after the
Rebellion of 1745. The great step then made
was in the art of English composition. In the
mathematical sciences, where the graces of writ¬
ing have no place, Scotland, in proportion to the
number of its inhabitants, was never, from the
time of Neper, left behind by any country in
Europe; nor ought it to be forgotten, that the
philosophy of Newton was publicly taught by
David Gregory at Edinburgh, and by his brother
James Gregory at St Andrew’s, before it was able
to supplant the vortices of Descartes in that
very university of which Newton was a member.1
The case was similar in every other liberal pur¬
suit, where an ignorance of the delicacies of the
English tongue was not an insuperable bar to
distinction. Even in the study of eloquence, as
far as it was attainable in their own vernacular
idiom, some of the Scottish pleaders, about the
era when the two kingdoms were united, seem
ambitiously, and not altogether unsuccessfully,
to have formed themselves upon models, which,
in modern times, it has been commonly suppos¬
ed to be more safe to admire than to imitate.2
Of the progress made in this part of the island
1 For this we have the authority of Whiston, the immediate successor of Sir Isaac Newton in the Lucasian Professorship
at Cambridge; and of Dr Reid, who was a nephew of the two Gregorys. “ Mr Gregory had already caused several of his
scholars to keep Acts, as we call them, upon several branches of the Newtonian Philosophy ; while we at Cambridge, poor
wretches, were ignominiously studying the fictitious hypotheses of the Cartesians.”—(Whiston’s Memoirs of his own Life.)
“ I have by me,”says Dr Reid, “a Thesis printed at Edinburgh, 1690, by James Gregory, who was at that time Pro¬
fessor of Philosophy at St Andrew’s, containing twenty-five positions; the first three relating to logic, and the abuse of it in
the Aristotelian and Cartesian philosophy. The remaining twenty-two positions are a compend of Newton’s Principia.
This Thesis, as was the custom at that time in the Scottish Universities, was to be defended in a public disputation, by the
candidates, previous to their taking their degree.”—(Hutton’s Mathematical Dictionary—Supplement by Duto the
article Gregory.
* See a splendid eulogium in the Latin language, by Sir George Mackenzie, on the most distinguished pleaders of his
time at the Scottish bar. Every allowance being made for the flattering touches of a friendly hand, his portraits can
scarcely be supposed not to have borne a strong and characteristical resemblance to the originals from which they were copied.
D1SS. I. PART II. ^ I
250
PRELIMINARY DISSERTATIONS.
Notes in Metaphysical and Ethical Studies, at a period
illustrations long prior to that which is commonly considered
^ as the commencement of our literary history, I
shall afterwards have occasion to speak. At
present, I shall only observe, that it was in the
Scottish universities that the philosophy of
Locke, as well as that of Newton, was first
adopted as a branch of academical education.
Note T, p. 107.
Extract of a letter from M. Allamand to Mr
Gibbon.—(See Gibbon’s Miscellaneous Works.)
<c Yous avez sans doute raison de dire que les
propositions evidentes dont il s’agit, ne sont pas
de simples idees, mais des jugemens. Mais ayez
aussi la complaisance de reconnoitre que M.
Locke les alleguant en exemple d’idees qui
passent pour innees, et qui ne le sont pas selon
lui, s’il y a ici de la meprise, c’est lui qu’il faut
relever la-dessus, et non pas moi, qui n’avois
autre chose a faire qu’a refuter sa maniere de
raisonner contre 1’inneite de ces idees ou juge-
mens la. D’ailleurs, Monsieur, vous remarquerez,
s’il vous plait, que dans cette dispute il s’agit en
effet, de savoir si certaines verites 6videntes et
communes, et non pas seulement certaines idees
simples, sont innees ou non. Ceux qui affirment,
ne donnent guere pour exemple d’idees simples
qui le soyent, que celles de Dieu, de 1’unite, et
de 1’existence; les autres exemples sont pris de
propositions completes, que vous appellez j uge-
mens.
<£ Mais, dites vous, y aura-t-il done des juge-
mens innes? Le jugement est il autre chose
qu’un acte de nos facultes intellectuelles dans la
comparison des idees? Le jugement sur les
verites evidentes, n’est il pas une simple vue de
ces verites la, un simple coup d’oeil que 1’esprit
jette sur elles ? J’accorde tout cela. Et de grace,
qu!est ce qu' idee ? N’est cepas vue, ou coup d’oeil,
si vous voulez ? Ceux qui definissent 1’idee autre-
ment, ne s’eloignent-ils pas visiblement du sens
et de 1’intention du mot ? Dire que les idees
sont les especes des chosesimprimees dans 1’esprit,
comme 1’image de 1’objet sensible est tracee dans
I’ceil, n’est ce pas jargonner plutot que definir ?
Or c’est la faute, qu’ont fait tous les metaphy- Notes
siciens, et quoique M. Locke 1’ait bien sentie, il xnustjacJions
a mieux aime se facher contre eux, et tirer contre
les girouettes de la place, que s’appliquer a
demeler ce galimatias. Que n’a-t-il dit, non
seulement il n’y a point d’idees innees dans le
sens de ces Messieurs; mais il n’y a point (F idees
du tout dans ce sens Id ; toute idee est un acte, une
vue, un coup d’oeil de Vesprit. Des lors deman der
s’il y a des idees innees, c’est demander s’il y a
certaines v^rites si evidentes et si communes que
tout esprit non stupide puisse naturellement, sans
culture et sans maitre, sans discussion, sans
raisonnement, les reconnoitre d’un coup d’oeil,
et souvent meme sans s’apper^evoir qu’on jette
ce coup d’oeil. L’affirmative me paroit incon¬
testable, et selon moi, la question est vuidee par la.
<£ Main tenant prenez garde, Monsieur, que
cette maniere d’entendre 1’affaire, va au but des
partisans des idees innees, tout comme la leur ;
et par la meme contredit M. Locke dans le sien.
Car pourquoi voudroit on qu’il y a eu des idees
innees ? C’est pour en opposer la certitude et
1’evidence au doute universel des sceptiques, qui
est ruine d’un seul coup, s’il y a des verites dont
la vue soit necessaire et naturelle a 1’homme.
Or vous sentez, Monsieur, que je puis leur dire
cela dans ma facon d’expliquer la chose, tout
aussi bien que les partisans ordinaires des idees
innees dans la leur. Et voila ce que semble
incommoder un peu M. Locke, qui, sans se
declarer Pyrrhonien, laisse appercevoir un peu
trop de foible pour le Pyrrhonisme, et a beaucoup
contribue a le nourrir dans ce siecle. A force
de vouloir marquer les bornes de nos connois-
sances, ce qui etoit fort necessaire, il a quelque-
fois tout mis en bornes.”
Note U, p. 108.
££ A decisive proof of this is afforded by the
allusions to Locke’s doctrines in the dramatic
pieces then in possession of the French stage,” &c.
In a comedy of Destouches (entitled La Fausse
Agnes), which must have been written long be¬
fore the period in question,1 the heroine, a live¬
ly and accomplished girl, supposed to be just
1 This little piece was first published in 1757, three years after the author’s death, which took place in 1754, in the se¬
venty-fourth year of his age. But we are told by D’Alembert, that from the age of sixty, he had renounced, from senti-
DISSERTATION FIRST.
251
Notes arrived from Paris at her father’s house in Poi-
Ulustmtions. tou5 is introduced as first assuming the appear-
ance 0f imbecility, in order to get rid of a dis¬
agreeable lover; and, afterwards, as pleading
her own cause in a mock trial before an absurd
old president and two provincial ladies, to convince
them that she is in reality not out of her senses.
In the course of her argument on this subject,
she endeavours to astonish her judges by an
ironical display of her philosophical knowledge ;
warning them of the extreme difficulty and nicety
of the question upon which they were about to
pronounce. “ Yous voulez juger de moi! mais,
pour juger sainement, il faut une grande eten-
due de connoissances; encore est il hien dou-
teux qu’il y en ait de certaines Avant
done que vous entrepreniez de prononcer sur mon
sujet, je deman de prealablement que vous exa-
miniez avec moi nos connoissances en general,
les degres de ces connoissances, leur etendue,
leur realite; que nous convenions de ce que e’est
que la verite, et si la verite se trouve effective-
ment. Apres quoi nous traiterons des proposi¬
tions universelles, des maximes, des proposi¬
tions frivoles, et de la foiblesse, ou de la solidite
de nos lumieres Quelque personnes
tiennent pour verite, que 1’homme nait avec cer¬
tains principes inees, certaines notions primitives,
certains caracteres qui sont comme graves dans
son espi’it, des le premier instant de son exist¬
ence. Pour moi, j’ai longtemps examine ce
sentiment, et j’entreprends de la combattre, de
le refuter, de Taneantir, si vous avez la patience
de m’ecouter.” I have transcribed hut a part
of this curious pleading; but, I presume, more
than enough to show, that every sentence, and
almost every word of it, refers to Locke’s doc¬
trines. In the second and third sentences, the
titles of the principal chapters in the fourth book
of his Essay are exactly copied. It was impos¬
sible that such a scene should have produced the
slightest comic effect, unless the hook alluded
to had been in very general circulation among
the higher orders; I might perhaps add, in much
more general circulation than it ever obtained
among that class of readers in England. At no Note*
period, certainly? since it was first published 11iUSj"ac|ions
(such is the difference of national manners),
could similar allusions have been made to it, or
to any other work on so abstract a subject, with
the slightest hope of success on the London stage.
And yet D’Alembert pronounces La Fausse
Agnes to he apiece, pleine de mouvement et de gaiete.
Note X, p. 110.
“ Descartes asserted,” says a very zealous
Lockist, M. de Voltaire, 44 that the soul, at its
coming into the body, is informed with the
whole series of metaphysical notions; knowing
God, infinite space, possessing all abstract ideas;
in a word, completely endued with the most su¬
blime lights, which it unhappily forgets at its
issuing from the womb.
44 With regard to myself,” continues the same
writer, 441 am as little inclined as Locke could be,
to fancy that, some weeks after I was conceived,
I was a very learned soul; knowing at that time
a thousand things which I forgot at my birth ;
and possessing, when in the womb (though to no
manner of purpose), knowledge which I lost the
instant I had occasion for it; and which I have
never since been able to recover perfectly.”—
Letters concerning the English Nation. Letter 13.
Whatever inferences may he deducible from
some of Descartes’s expressions, or from the
comments on these expressions by some who as¬
sumed the title of Cartesians, I never can per¬
suade myself, that the system of innate ideas, as
conceived and adopted by him, was meant to
give any sanction to the absurdities here treated
by Voltaire with such just contempt. In no
part of Descartes’s works, as far as I have been
able to discover, is the slightest ground given
for this extraordinary account of his opinions.
Nor was Descartes the first person who intro¬
duced this language. Long before the date ol
his works, it was in common use in England;
and is to be found in a Poem of Sir John Davis,
published four years before Descartes was horn.
ments of piety, all thoughts of writing for the stage—(Eloge de Destouches.) This carries the date of all his dramatic
works, at least as far back as 1740. As for Destouches’s own familiarity with the writings of Locke, it is easily accounted
for by his residence in England from 1717 to 1723, where he remained, for some time alter the departure of Cardinal Du¬
bois, as Charge d'Affaires. Voltaire did not visit England till 1727*
252
PRELIMINARY DISSERTATIONS.
Notes (See Sect. XXYI. of The Immortality of the
and Soul.) The title of this Section expressly as-
serts, That there are innate ideas in the soul.
In one of Descartes’s letters, he enters into
some explanations with respect to this part of
his philosophy, which he complains had been
very grossly misunderstood or misrepresented.
To the following passage I have no doubt that
Locke himself would have subscribed. It strikes
myself as so very remarkable, that, in order to
attract to it the attention of my readers, I shall
submit it to their consideration in an English
translation.
“ When I said that the idea of God is innate
in us, I never meant more than this, that Na¬
ture has endowed us with a faculty by which we
may know Godbut I have never either said
or thought, that such ideas had an actual exist¬
ence, or even that they were species distinct from
the faculty of thinking. I will even go farther,
and assert that nobody has kept at a greater dis¬
tance than myself from all this trash of scholas¬
tic entities, insomuch that I could not help smil¬
ing when I read the numerous arguments which
Regius has so industriously collected to show
that infants have no actual knowledge of God
while they remain in the womb. Although the
idea of God is so imprinted on our minds, that
every person has within himself the faculty of
knowing him, it does not follow that there may
not have been various individuals who have
passed through life without ever making this
idea a distinct object of apprehension; and, in
truth, they who think they have an idea of a
plurality of Gods, have no idea of God what¬
soever.”—(Cartesii, Epist. Pars I. Epist.
xcix.)
After reading this passage from Descartes,
may I request of my readers to look back to the
extracts in the beginning of this note, from Vol¬
taire’s letters ? A remark of Montesquieu, oc¬
casioned by some strictures hazarded by this
lively but very superficial philosopher on the
Spirit of Laws, is more peculiarly applicable to
him when he ventures to pronounce judgment
on metaphysical writers : “ Quant a Voltaire,
il a trop d!esprit pour m’entendre ; tous les livres
qu’il lit, il les fait, apres quoi il approuve on
critique ce qu’il a fait.”—(Lettre d M. VAbbe de
Guasco.) The remark is applicable to other Notes
critics as well as to Voltaire. ^ and.
The prevailing misapprehensions with respect
to this, and some other principles of the Carte¬
sian metaphysics, can only be accounted for by
supposing, that the opinions of Descartes have
been more frequently j udged of from the glosses
of his followers, than from his own works. It
seems to have never been sufficiently known to
his adversaries, either in France or in England,
that, after his philosophy had become fashion¬
able in Holland, a number of Dutch divines,
whose opinions differed very widely from his,
found it convenient to shelter their own errors
under his established name; and that some of
them went so far as to avail themselves of his
authority in propagating tenets directly oppo¬
site to his declared sentiments. Hence a dis¬
tinction of the Cartesians into the genuine and
the josewcfo-Cartesians; and hence an inconsis¬
tency in their representations of the metaphysi¬
cal ideas of their master, which can only be
cleared up by a reference (seldom thought of)
to his own very concise and perspicuous text.
(Fabricii Bib. Gr. lib. iii. cap. vi. p. 183.
Heinecc. El. Hist. Phil. § cx.)
Many of the objections commonly urged against
the innate ideas of Descartes are much more ap¬
plicable to the innate ideas of Leibnitz, whose
language concerning them is infinitely more
hypothetical and unphilosophical; and some¬
times approaches nearly to the enthusiastic theo-
logy of Plato and of Cudworth. Nothing in
the works of Descartes bears any resemblance,
in point of extravagance, to what follows: “ Pul-
cherrima multa sunt Platonis dogmata, esse
in divina mente mundum intelligibilem, quern
ego quoque vocare soleo regionem idearum; ob-
jectum sapientise esse ru ovrwg ovm, substantias
nempe simplices, quse a me monades appellantur,
et semel existentes semper perstant, Kgura hixraa
rng fays, id est, Deum et Animas, et harum po-
tissimas mentes, producta a Deo simulacra divi-
nitatis Porro quae vis mens, ut recte Plotinus,
quendam in se mundum intelligibilem continet,
imo mea sententia et hunc ipsum sensibilem sibi
reprsesentat Sunt in nobis semina eorum, quae
discimus, ideae nempe, et quae inde nascuntur,
aeternae veritates Longe ergo praeferendae
DISSERTATION FIRST.
Notes sunt Pktonis rwtitice innata, quas reminiscentice
Illustrations.nomine velavit, tabula? rasa; Aristotelis et Lockii,
aliorumque recentiorum, qui philoso-
phantur.”—(Leib. Opera, Tom. II. p. 223.)
Wild and visionary, however, as the forego¬
ing propositions are, if the names of Gassendi
and of Hobbes had been substituted instead of
those of Aristotle and of Locke, I should have
been disposed to subscribe implicitly to the
judgment pronounced in the concluding sen¬
tence. The metaphysics of Plato, along with a
considerable alloy of poetical fiction, has at least
the merit of containing a large admixture of im¬
portant and of ennobling truth; while that of
Gassendi and of Hobbes, besides its inconsis¬
tency with facts attested, every moment, by our
own consciousness, tends directly to level the
rational faculties of man with the instincts of
the brutes.
In the Acta Eruditorum for the year 1684,
Leibnitz observes, that “ in the case of things
which we have never thought of, the innate ideas
in our minds may be compared to the figure of
Hercules in a block of marble.” This seems to
me to prove, that the difference between him
and Locke was rather in appearance than in
reality; and that, although he called those ideas
innate which Locke was at pains to trace to sen¬
sation or to reflection, he would have readily
granted, that our first knowledge of their exis¬
tence was coeval with the first impressions made
on our senses by external objects. That this
was also the opinion of Descartes is still more
evident, notwithstanding the ludicrous point of
view in which Voltaire has attempted to exhibit
this part of his system.
Note Y, p. 111.
Mr Locke seems to have considered this use
of the word reflection as peculiar to himself; but
it is perfectly analogous to the %ivr\(Siig xuxXhca/ of
the Greek philosophers, and to various expres¬
sions which occur in the works of John Smith
of Cambridge, and of Dr Cudworth. We find
it in a Poem on the Immortality of the Soul, by
Sir John Davis, Attorney-General to Queen
Elizabeth; and probably it is to be met with in Notes
English publications of a still earlier date. atl,i
Illustrations.
All things without which round about we see,
We seek to know, and have wherewith to do ;
But that whereby we reason, live, and be,
Within ourselves, we strangers are thereto.
Is it because the mind is like the eye,
Through which it gathers knowledge by degrees ;
Whose rays reflect not, but spread outwardly ;
Not seeing itself, when other things it sees ?
No, doubtless; for the mind can backward cast
Upon herself her understanding light;
But she is so corrupt, and so defac’d,
As her own image doth herself affright.
As is the fable of the Lady fair,
Which for her lust was turned into a cow >
When thirsty, to a stream she did repair,
And saw herself transform’d, she wist not how :
At first she startles, then she stands amaz’d ;
At last with terror she from hence doth fly,
And loathes the wat’ry glass wherein she gaz’d,
And shuns it still, although for thirst she die.
I’or even at first reflection she espies
Such strange chimeras, and such monsters there;
Such toys, such antics, and such vanities,
As she retires and shrinks for shame and fear.
I have quoted these verses, chiefly because I
think it not improbable that they may have
suggested to Gray the following very happy
allusion in his fine Fragment De Principiis Co-
gitandi:
Qualis Hamadryadum quondam si forte sororum
Una, novos peregrans saltus, et devia rura
(Atque illam in viridi suadet procumbere ripa
Fontis pura quies, et opaci frigoris umbra) ;
Dum prona in latices speculi de margine pendet,
Mirata est subitam venienti occurrere Nympham
Mox eosdem, quos ipsa, artus, eadem ora gerentem
Una inferre gradus, una succedere sylvie
Aspicit alludens; seseque agnoscit in undis :
Sic sensu interno rerum simulacra suarum
Mens ciet, et proprios observat conscia vultus.
Note Z, p. 122.
The chief attacks made in England on Locke’s
Essay, during his own lifetime, were by Edward
Stillingfleet, Bishop of Worcester; John Nor¬
ris, 1 Rector of Bemerton; Henry Lee, B. D. ;
Of this person, who was a most ingenious and original thinker. I shall have occasion afterwards to speak.
PRELIMINARY DISSERTATIONS.
Notes and the Reverend Mr Lowde (author of a JDis-
Illustrations.course Gonceming the Nature of Man). Of these
four writers, the first is the only one whose ob¬
jections to Locke are now at all remembered in
the learned world; and for this distinction, Stil-
lingfleet is solely indebted (I speak of him here
merely as a metaphysician, for in some other
departments of study, his merits are universally
admitted) to the particular notice which Locke
has condescended to take of him, in the Notes
incorporated with the later editions of his Essay.
The only circumstance which renders these
Notes worthy of preservation, is the record they
furnish of Locke’s forbearance and courtesy, in
managing a controversy carried on, upon the
other side, with so much captiousness and aspe¬
rity. An Irish bishop, in a letter on this sub¬
ject to Mr Molyneux, writes thus: “ I read Mr
Locke’s letter to the Bishop of Worcester with
great satisfaction, and am wholly of your opi¬
nion, that he has fairly laid the great bishop on
his back, but it is with so much gentleness, as
if he were afraid not only of hurting him, hut
even of spoiling or tumbling his clothes.”
The work of Lee is entitled “ Anti-scepticism,
or Notes upon each chapter of Mr Locke’s Es¬
say concerning Human Understanding, with an
explanation of all the particulars of which he
treats, and in the same order. By Henry Lee,
B. D. formerly Fellow of Emanuel College in
Cambridge, now Rector of Tichmarsh in North¬
amptonshire.”—London, 1702, in folio.
The strictures of this author, which are often
acute and sometimes just, are marked through¬
out with a fairness and candour rarely to be met
with in controversial writers. It will appear
remarkable to modern critics that he lays parti¬
cular stress upon the charms of Locke’s style,
among the other excellencies which had conspir¬
ed to recommend his work to public favour.
es The celebrated author of the Essay on Hu¬
man Understanding has all the advantages desir¬
able to recommend it to the inquisitive genius
of this age ; an avowed pretence to new methods
of discovering truth and improving learning; an
unusual coherence in the several parts of his
scheme; a singular clearness in his reasonings , Notes
and above all, a natural elegancy of style; an jiiusat"^tions
unaffected beauty in his expressions; a j ust pro-
portion and tuneable cadence in all his periods.”
—(See the Epistle Dedicatory.)
Note A A, p. 125.
For the information of some of my readers,
it may be proper to observe, that the word influx
came to be employed to denote the action of body
and soul on each other, in consequence of a pre¬
vailing theory which supposed that this action
was carried on by something intermediate (whe¬
ther material or immaterial was not positively
decided) flowing from the one substance to the
other. It is in this sense that the word is un¬
derstood by Leibnitz, when he states as an in¬
surmountable objection to the theory of influx,
that “ it is impossible to conceive either mate¬
rial particles or immaterial qualities to pass
from body to mind, or from mind to body.”
Instead of the term influx, that of influence
came gradually to be substituted by our English
writers; but the two words were originally
synonymous, and were used indiscriminately as
late as the time of Sir Matthew Hale.—(See his
Primitive Origination of Mankind.)
In Johnson’s Dictionary, the primitive and
radical meaning assigned to the word influence
(which he considers as of French extraction) is
“ the power of the celestial aspects operating
upon terrestrial bodies and affairsand in the
Encyclopaedia of Chambers, it is defined to be
“ a quality supposed to flow from the bodies
of the stars, either with their heat or light, to
which astrologers vainly attribute all the events
which happen on the earth.” To this astrolo¬
gical use of the word Milton had plainly a re¬
ference in that fine expression of his L’ Allegro,
“ Store of ladies whose bright eyes
“ Rain influence.1"1
It is a circumstance worthy of notice, that a
word thus originating in the dreams of astro-
r The explanation of the word influence, given in the Dictionary of the French Academy, accords perfectly with the tenor
of the above remarks. “ Yertu qui, suivant les Astrologues, decoule des Astres sur les corps sublunaires.”
DISSERTATION FIRST.
255
Notes logers and schoolmen, should now, in our lan-
iins^adti0tls. guage, be appropriated almost exclusively to
politics. “ Thus,” says Blackstone, <£ are the
electors of one branch of the legislature secured
from any undue influence from either of the other
two, and from all external violence and com¬
pulsion ; but the greatest danger is that in which
themselves co-operate by the infamous practice
of bribery and corruption.” And again, <£ The
crown has gradually and imperceptibly gained
almost as much in influence as it has lost in pre¬
rogative.”
In all these cases, there will be found at bot¬
tom one common idea, the existence of some se¬
cret and mysterious connection between two
things, of which connection it is conceived to be
impossible or unwise to trace what Bacon calls
the latens processus.
Note BB, p. 126.
After these quotations from Locke, added to
those which I have already produced from the
same work, the reader may judge of the injustice
done to him by Leibnitz, in the first sentence of
his correspondence with Clarke.
££ II semble que la religion naturelle meme
s’affoiblit extremement. Plusieurs font les ames
corporelles; d’autres font Dieu lui-meme cor-
porel.
££ M. Locke et ses sectateurs, doutent au moins,
si les ames ne sont materielles, et naturellement
perissables.”
Dr Clarke, in his reply to this charge, admits
that ££ some parts of Locke’s writings may justly
be suspected as intimating his doubts whether
the soul be immaterial or no; but herein (he adds)
he has been followed only by some Materialists,
enemies to the mathematical principles of philo¬
sophy, and Who approve little or nothing in Mr
Locke’s writings, but his errors.”
To those who have studied with care the whole
writings of Locke, the errors here alluded to will
appear in a very venial light when compared
with the general spirit of his philosophy. Nor
can I forbear to remark farther on this occasion,
that supposing Locke’s doubts concerning the
immateriality of the soul to have been as real as
Clarke seems to have suspected, this very cir¬
cumstance would only reflect the greater lustre Notes
on the soundness of his logical views concerning' and
n ® Illustrations
the proper method ot studying the mind;—in
the prosecution of which study, he has adhered
much more systematically than either Descartes
or Leibnitz to the exercise of reflection, as the
sole medium for ascertaining the internal phe¬
nomena; describing, at the same time, these
phenomena in the simplest and most rigorous
terms which our language affords, and avoiding,
in a far greater degree than any of his prede¬
cessors, any attempt to explain them by analogies
borrowed from the perceptions of the external
senses.
I before observed, that Leibnitz greatly under¬
rated Locke as a metaphysician. It is with re¬
gret I have now to mention, that Locke has by
no means done justice to the splendid talents
and matchless erudition of Leibnitz. In a letter
to his friend Mr Molyneux, dated in 1697, he
expresses himself thus : ££ I see you and I agree
pretty well concerning Mr Leibnitz; and this
sort of fiddling makes me hardly avoid thinking
that he is not that very great man as has been
talked of him.” And in another letter, written
in the same year to the same correspondent, after
referring to one of Leibnitz’s Memoirs in the
Acta Eruditorum (De Primae Philosophise Emen-
datione), he adds, ££ From whence I only draw
this inference, that even great parts will not master
any subject without great thinking, and that even
the largest minds have but narrow swallows.”
Let me add, that in my quotations from Eng¬
lish writers, I adhere scrupulously to their own
phraseology, in order to bring under the eye of
my readers, specimens of English composition
at different periods of our history. I must re¬
quest their attention to this circumstance, as
some expressions in the former part of this Dis¬
sertation, which have been censured as Scot¬
ticisms, occur in extracts from authors who, in
all probability, never visited this side of the
Tweed.
Note CC, p. 131.
After studying, with all possible diligence,
what Leibnitz has said of his monads in different
parts of his works, I find myself quite incom-
256
PRELIMINARY DISSERTATIONS.
Notes petent to annex any precise idea to the word as
an<1. he has employed it. I shall, therefore, aim at
nothing more in this note, but to collect, into as
small a compass as I can, some of his most
intelligible attempts to explain its meaning.
££ A substance is a thing capable of action.
It is simple or compounded. A simple substance
is that which has no parts. A compound sub¬
stance is an aggregate of simple substances or of
monads.
££ Compounded substances, or bodies, are mul¬
titudes. Simple substances, lives, souls, spirits,
are units.1 Such simple substances must exist
everywhere; for without simple substances
there could he no compounded ones. All nature
therefore is full of life.”—(Tom. II. p. 32.)
££ Monads, having no parts, are neither ex¬
tended, figured, nor divisible. They are the real
atoms of nature, or, in other words, the elements
of things.”—(Tom. II. p. 20.)
(It must not, however, he imagined, that the
monads of Leibnitz have any resemblance to
what are commonly called atoms by philoso¬
phers. On the contrary, he says expressly, that
££ monads are not atoms of matter, but atoms
of substances ;—real units, which are the first
principles in the composition of things, and the
last elements in the analysis of substances;—of
which principles or elements, what we call bo¬
dies are only the phenomena.',,)—(Tom. II. pp.
53. 325.)
In another passage we are told, that ££ a mo¬
nad is not a material but & formal atom, it being
impossible for a thing to he at once material,
and possessed of a real unity and indivisibility.
It is necessary, therefore,” says Leibnitz, ££ to
revive the obsolete doctrines of substantial forms
(the essence of which consists in force), separat¬
ing it, however, from the various abuses to which
it is liable.”—{Ibid. p. 50.)
££ Every monad is a living mirror, represent¬
ing the universe, according to its particular
point of view, and subject to as regular laws as
the universe itself.”
£‘ Every monad, with a particular body, makes
a living substance.”
££ The knowledge of every soul (dme) extends Notes
to infinity, and to all things; but this know- iiiustrna^ons
ledge is confused. As a person walking on the
margin of the sea, and listening to its roar,
hears the noise of each individual wave of
which the whole noise is made up, but without
being able to distinguish one sound from ano¬
ther, in like manner, our confused perceptions
are the result of the impressions made upon us
by the whole universe. The case (he adds) is
the same with each monad.,,
££ As for the reasonable soul or mind {Vesprit),
there is something in it more than in the monads,
or even than in those souls which are simple. It
is not only a mirror of the universe of created
things, but an image of the Deity. Such minds
are capable of reflected acts, and of conceiving
what is meant by the words I, substance, monad,
soul, mind; in a word, of conceiving things and
truths unconnected with matter; and it is this
which renders us capable of science and of de¬
monstrative reasoning.
££ What becomes of these souls, or forms, on
the death of the animal ? There is no alterna¬
tive (replies Leibnitz) hut to conclude, that not
only the soul is preserved, but that the animal
also with its organical machine continues to exist,
although the destruction of its grosser parts has
reduced it to a smallness as invisible to our eyes
as it was before the moment of conception.
Thus neither animals nor souls perish at death;
nor is there such a thing as death* if that word
he understood with rigorous and metaphysical
accuracy. The soul never quits completely the
body with which it is united, nor does it pass
from one body into another with which it had
no connection before; a metamorphosis takes
place, but there is no metempsychosis.—(Tom.
II. pp. 51, 52.)
On this part of the Leibnitzian system,
D’Alembert remarks, that it proves nothing
more than that the author had perceived better
than any of his predecessors, the impossibility of
forming a distinct idea of the nature of matter ;
a subject, however (D’Alembert adds), on which
the theory of the monads does not seem calcu-
1 “ Les substances simples, les vies, les ames, les esprits, sent des unitds.'
DISSERTATION FIRST.
257
Notes lated to throw much light. I would rather say
Illustrations, (without altogether denying the justness of
D’Alembert’s criticism), that this theory took its
rise from the author’s vain desire to explain the
nature of forces; in consequence of which he
suffers himself perpetually to be led astray from
those sensible effects which are exclusively the
proper objects of physics, into conjectures con¬
cerning their efficient causes, which are altoge¬
ther placed beyond tbe reach of our research.
Note D D, p. 134.
The metaphysical argument advanced by the
Leibnitzians in proof of tbe law of continuity has
never appeared to me to be satisfactory. “ If a
body at rest (it has been said) begins, per saltum,
to move with any finite velocity, then this body
must be at the same indivisible instant in two
different states, that of rest and of motion, which
is impossible.” 1
As this reasoning, though it relates to a phy¬
sical fact, is itself wholly of a metaphysical na¬
ture ; and as the inference deduced from it has
been generalised into a law, supposed to extend
to all the various branches of human knowledge,
it is not altogether foreign to our present sub¬
ject briefly to consider how far it is demonstra¬
tively conclusive, in this simplest of all its pos¬
sible applications.
On the above argument, then, I would re¬
mark, 1. That the ideas both of rest and of mo¬
tion, as well as the more general idea conveyed
by the word state, all of them necessarily involve
the idea of time or duration ; and, consequently,
a body cannot be said to be in a state either of
rest or of motion, at an indivisible instant. Whe¬
ther the body be supposed (as in the case of mo¬
tion) to change its place from one instant to an¬
other ; or to continue (as in that of rest) for an
instant in the same place, the idea of some finite Notes
portion of time will, on the slightest reflection, i]iustrations.
be found to enter as an essential element into
our conception of the physical fact.
2. Although it certainly would imply a con¬
tradiction to suppose a body to be in two differ¬
ent states at the same instant, there does not
appear to be any inconsistency in asserting that
an indivisible instant may form the limit between
a state of rest and a state of motion. Suppose
one half of this page to be painted white, and the
other black, it might, I apprehend, be said with
the most rigorous propriety? that the transition
from the one colour to the other was made per
saltum ; nor do I think it would be regarded as
a valid objection to this phraseology, to repre¬
sent it as one of its implied consequences, that
the mathematical line which forms their common
limit, must at once be both black and white.
It seems to me quite impossible to elude the
force of this reasoning, without having recourse
to the existence of something intermediate be¬
tween rest and motion, which does not partake of
the nature of either.
Is it conceivable that a body can exist in any
state which does not fall under one or other of
the two predicaments, rest or motion ? If this
question should be answered in the negative,
will it not follow that the transition from one
of these states to the other must, of necessity,
be made per saltum, and must consequently vio¬
late the supposed law of continuity ? Indeed,
if such a law existed, how could a body at rest
begin to move, or a body in motion come to a
state of rest ?
But farther, when it is said that “ it is im¬
possible for a body to have its state changed
from motion to rest, or from rest to motion,
without passing through all the intermediate de¬
grees of velocity,” what are we to understand by
1 “ Si toto tempore,” says Father Boscovich, speaking of the Law of Continuity in the Collision of Bodies, “ ante con-
tactum subsequentis corporis superficies antecedens habuit 12 gradus velocitatis, et sequenti 9, saltu facto momentaneo ipso
initio contactus; in ipso momento ea tempora dirimente debuissent habere et 12 et 9 simul, quod est absurdum. Duas
enim velocitates simul habere corpus non potest.”—Theoria Phil. Nat. &c.
Boscovich, however, it is to be observed, admits the existence of the Law of Continuity in the phenomena of Motion
alone (§ 143), and rejects it altogether in things co-existent with each other (§ 142). In other cases, he says, Nature does
not observe the Law of Continuity with mathematical accuracy, but only affects it; by which expression he seems to mean,
that, where she is guilty of a saltus, she aims at making it as moderate as possible. The expression is certainly deficient in
metaphysical precision; but it is not unworthy of attention, inasmuch as it affords a proof, that Boscovich did not (with
the Leibnitzians) conceive Nature, or the Author of Nature, as obeying an irresistihle necessity in observing or not observing
the Law of Continuity.
D1SS. I. PART II. 2 K.
258
PRELIMINARY DISSERTATIONS.
Notes the intermediate degrees of velocity between rest and
and. motion ? Is not every velocity, how small soever,
a finite velocity; and does it not diner as essen¬
tially trom a state of rest, as the velocity of
light ?
It is observed by Mr Playfair (Dissertation
on the Progress of Mathematical and Physical
Science, Part I. Sect, iii.), that Galileo was the
first who maintained the existence of the law of
continuity, and who made use of it as a principle
in his reasonings on the phenomena of motion.
Mr Playfair, however, with his usual discrimi¬
nation and correctness, ranks this among the
mechanical discoveries of Galileo. Indeed, it
does not appear that it was at all regarded by
Galileo (as it avowedly was by Leibnitz) in the
light of a metaphysical and necessary law, which
could not by any possibility be violated in any
of the phenomena of motion. It was probably
first suggested to him by the diagram which he
employed to demonstrate, or rather to illustrate,
the uniformly accelerated motion of falling bo¬
dies ;1 and the numberless and beautiful exem¬
plifications of the same law which occur in pure
geometry, sufficiently account for the disposition
which so many Mathematicians have shown to
extend it to all those branches of physics which
admit of a mathematical consideration.
My late illustrious friend, who, to his many
other great and amiable qualities, added the most
perfect fairness and candour in his inquiries after
truth, has (in the Second Part of his Disserta¬
tion) expressed himself with considerably great¬
er scepticism concerning the law of continuity,
than in his Outlines of Natural Philosophy. In
that work he pronounced the metaphysical ar¬
gument, employed by Leibnitz to prove its ne¬
cessity, “ to be conclusive.” (Sect. VI. § 99, b.)
In the Second Part of his Dissertation (Sect, ii.),
he writes thus on the same subject:
“ Leibnitz considered this principle as known
a priori, because, if any saltus were to take place,
that is, if any change were to happen without Note?
the intervention of time, the thing changed must iiiu^rationg
be in two different conditions at the same indi-
vidual instant, which is obviously impossible.
Whether this reasoning be quite satisfactory or
no, the conformity of the law to the facts gene¬
rally observed cannot but entitle it to great au¬
thority in judging of the explanations and theo¬
ries of natural phenomena.”
The phrase, Law of Continuity, occurs repeat¬
edly in the course of the correspondence be¬
tween Leibnitz and John Bernouilli, and ap¬
pears to have been first used by Leibnitz him¬
self. The following passage contains some in¬
teresting particulars concerning the history of
this law : “ Lex Continuitatis, cum usque adeo
sit rationi et naturae consentanea, et usum ha-
beat tarn late patentem, mirum tamen est earn a
nemine (quantum recorder) antea adhibitam
fuisse. Mentionem ejus aliquam feceram olim in
Novellis Reipublicse Literarise (Juillet, 1687, p.
744), occasione collatiunculse cum Malebranchio,
qui ideo meis considerationibus persuasus, suam
de legibus motus in Inquisitione Veritatis exposi-
tam doctrinam postea mutavit; quod brevi li-
bello edito testatus est, in quo ingenue occa-
sionem mutationis exponit. Sed tamen paullo
pr emptier, quam par erat, fuit in no vis legibus
constituendis in eodem libello, antequam mecum
communicasset; nec tantum in veritatem, sed
etiam in illam ipsam Legem Continuitatis, etsi
minus aperte, denuo tamen impegit; quod nolui
viro optimo objicere, ne viderer ejus existima-
tioni detrahere velle.”—Epist. Leibnit. ad Jo^
Bernouilli, 1697.
From one of John Bernouilli’s letters to Leib
nitz, it would appear that he had himself a con¬
viction of the truth of this law, before he had
any communication with Leibnitz upon the
subject.
“ Placet tuum criterium pro examinandis re-
1 Descartes seems, from his correspondence with Mersenne, to have been much puzzled with Galileo’s reasonings con¬
cerning the descent of falling bodies ; and in alluding to it, has, on different occasions, expressed himself with an indecision
and inconsistency of which few instances occur in his works. (Vide Cartesii Epist. Pars II. Epist. xxxiv. xxxv. xxxvii. xci.)
His doubts on this point will appear less surprising, if compared with a passage in the article Mtchanique in D’Alembert s
El'tmens de Philosophie. “ Tous les philosophes paroissent convenir, que la vitesse avec laquelle les corps qui tombent com-
mencent a se mouvoirest absolument nulle,” &c. &c—(See his Melanges, Tom. IV. p. 219, 2.20.)
DISSERTATION FIRST.
259
Notes
and
Illustrations.
gulis motuum, quod legem continuitatis vocas;
est enim per se evidens, et velut a natura nobis
inditum, quod evanescente insequalitate hypo-
thesium, evanescere quoque debeant insequali-
tates eventuum. Hinc multoties non satis mi-
rari potui, qui fieri potuerit, ut tam incongruas,
tam absonas, et tam raanifeste inter se pug-
nantes regulas, excepta sola prima, potuerit con-
dere Cartesius, vir alias summi ingenii. Mihi
videtur vel ab infante falsitatem illarum palpari
posse, eo quod ubique saltus ille, naturae adeo
inimicus, manifesto nimis elucet.”—Epist. Ber-
nouilli ad Leib. 1696. Vide Leibnitzii et Jo.
Bernouilli Comm. Epist. 2 vols. 4to. Lausannse
et Genevae, 1745.)
Note E E, p. 134.
Mais il restoit encore la plus grande question,
de ce que ces ames ou ces formes deviennent
par la mort de Panimal, ou par la destruction
de I’mdividu de la substance organise. Et
c’est ce qui embarrasse le plus; d’autant qu’il
paroit peu raisonnable que les ames restent
inutilement dans un chaos de matiere confuse.
Cela m’a fait juger enfin qu’il n’y avoit qu’un
seul parti raisonnable a prendre; et c’est celui
de la conservation non seulement de 1’ame,
mais encore de 1’animal meme, et de la ma¬
chine organique; quoique la destruction des
parties grossieres 1’ait reduit a une petitesse
qui n’echappe pas moins a nos sens que celle
ou il etoit avant que de naitre.—(Leib. Op.
Tom. II. p. 51.)
.... Des personnes fort exactes aux experi¬
ences se sont deja aper^ues de notre terns,1
qu’on peut douter, si jamais un animal tout a
fait nouveau est produit, et si les animaux tout
en vie ne sont deja en petit avant la conception
dans les semences aussi bien que les plantes.
Cette doctrine etant posee, il sera raisonnable de
juger, que ce qui ne commence pas de vivre ne
cesse pas de vivre non plus; et que la mort,
comme la generation, n’est que la transforma¬
tion du meme animal qui est tantot augment6,
et tantot diminue.—(Ibid. pp. 42, 43.)
. . . . Et puisqu’ ainsi il n’y a point de pre- Notes
miere naissance ni de generation entierement jii^adon'
nouvelle de 1’animal, il s’ensuit qu’il n’y en aura
point d’extinction finale, ni de mort entiere prise
a la rigueur metaphysique; et que, par conse¬
quent, au lieu de la transmigration des ames, il
n’y a qu’une transformation d’un meme animal,
selon que les organes sont plies differement, et
plus ou moins developpes.—(Ibid. p. 52.)
Quant a la Metempsycose, je crois que 1’ordre
ne I’admet point; il veut que tout soit expli¬
cable distinctement, et que rien ne se fasse par
saut. Mais le passage de Tame d’un corps dans
1’autre seroit un saut etrange et inexplicable.
Il se fait toujours dans 1’animal ce qui se fait pre-
sentement: C’est que le corps est dans un
changement continuel, comme un fleuve, et ce
que nous appellons generation ou mort, n’est
qu’un changement plus grand et plus prompt
qu’a 1’ordinaire, tel que seroit le saut ou la ca-
taracte d’line riviere. Mais ces sauts ne sont
pas absolus et tels que je desaprouve; comme
seroit celui d’un corps qui iroit d’un lieu a un
autre sans passer par le milieu. Et de tels sauts
ne sont pas seulement defendus dans les mouvemens,
mais encore dans tout ordre des choses ou des veri-
tes.—The sentences which follow afford a proof
of what I have elsewhere remarked, how much
the mind of Leibnitz was misled, in the whole
of this metaphysical theory, by habits of think¬
ing formed in early life, amidst the hypothetical
abstractions of pure geometry; a prejudice (or
idol of the mathematical den) to which the most
important errors of his philosophy might, with¬
out much difficulty, be traced.—Or comme dans
une ligne de geometric il y a certains points
distingues, qu’on appelle sommets, points d’in-
flexion, points de rebroussement, ou autrement;
et comme il y en a des lignes qui en ont une
infinite, c’est ainsi qu’il faut concevoir dans la
vie d’un animal ou d’une personne les terns
d’un changement extraordinaire, qui ne laissent
pas d’etre dans la regie generale; de meme que
les points distingues dans la courbe se peuvent
determiner par sa nature generale ou son equa¬
tion. On peut toujours dire d’un animal c’est
1 The experiments here referred to are the observations of Swammerdam, Malpighi, and Lewenhoeck.
260
PRELIMINARY DISSERTATIONS.
Notes
and
Illustrations.
tout comme ici, la difference n’est que
ou moms.”—(Tom. Y. p. IS.)
du plus
Note FF, p. 136.
The praise which I have bestowed on this
Memoir renders it necessary for me to take
some notice of a very exceptionable proposition
which is laid down in the first paragraph, as a
fundamental maxim,—that “ all proper names
were at first appellativesa proposition so
completely at variance with the commonly re¬
ceived opinions among later philosophers, that
it seems an object of some curiosity to inquire,
how far it is entitled to plead in its favour the
authority of Leibnitz. Since the writings of
Condillac and of Smith, it has, so far as I know,
been universally acknowledged, that, if there be
any one truth in the Theoretical History of Lan¬
guage, which we are entitled to assume as an
incontrovertible fact, it is the direct contrary of
the above proposition. Indeed, to assert that
all proper names were at first appellatives,
would appear to be nearly an absurdity of the
same kind as to maintain, that classes of objects
existed before individual objects had been
brought into being.
When Leibnitz, however, comes to explain
his idea more fully, we find it to be something
very different from what his words literally im¬
ply ; and to amount only to the trite and indis¬
putable observation, that, in simple and primi¬
tive languages, all proper names (such as the
names of persons, mountains, places of resi¬
dence, &c.) are descriptive or significant of cer¬
tain prominent and characteristical features,
distinguishing them from other objects of the
same class;—a fact, of which a large proportion
of the surnames still in use, all over Europe, as
well as the names of mountains, villages, and
rivers, when traced to their primitive roots,
afford numerous and well known exemplifica¬
tions.
Not that the proposition, even when thus ex¬
plained, can be assumed as a general maxim.
It holds, indeed, in many cases, as the Celtic
and the Saxon languages abundantly testify in
our own island; but it is true only under cer¬
tain limitations, and it is perfectly consistent
with the doctrine delivered on this subject by No“*
the greater part of philologers for the last fifty illustrations,
years.
In the history of language, nothing is more
remarkable, than the aversion of men to coin
words out of unmeaning and arbitrary sounds;
and their eagerness to avail themselves of the
stores already in their possession, in order to
give utterance to their thoughts on the new
topics which the gradual extension of their ex¬
perience is continually bringing within the circle
of their knowledge. Hence metaphors, and
other figures of speech; and hence the various
changes which words undergo, in the way of
amplification, diminution, composition, and the
other transformations of elementary terms which
fall under the notice of the etymologist. Were
it not, indeed, for this strong and universal bias
of our nature, the vocabulary of every language
would, in process of time, become so extensive
and unwieldy, as to render the acquisition of
one’s mother tongue a task of immense diffi¬
culty, and the acquisition of a dead or foreign
tongue next to impossible. It is needless to
observe, how immensely these tasks are facili¬
tated by that etymological system which runs,
more or less, through every language; and
which everywhere proceeds on certain analogi¬
cal principles, which it is the business of the
practical grammarian to reduce to general rules,
for the sake of those who wish to speak or to
write it with correctness.
In attempting thus to trace backwards the
steps of the mind towards the commencement
of its progress, it is evident, that we must at
last arrive at a set of elementary and primitive
roots, of which no account can be given, but
the arbitrary choice of those who first hap¬
pened to employ them. It is to this first stage
in the infancy of language that Mr Smith’s re¬
marks obviously relate; whereas the proposi¬
tion of Leibnitz, which gave occasion to this
note, as obviously relates to its subsequent
stages, when the language is beginning to as¬
sume somewhat of a regular form, by composi¬
tions and other modifications of the materials
previously collected.
From these slight hints it may be inferred,
l$f, That the proposition of Leibnitz, although
DISSERTATION FIRST.
201
Notes it may seem, from the very inaccurate and
atld. eauivocal terms in which it is expressed, to
Illustrations. U . . 1 .
stand in direct opposition to the doctrine or
Smith, was really meant by the author to state
a fact totally unconnected with the question
under Smith’s consideration. 2dly, That even
in the sense in which it was understood by the
author, it fails entirely, when extended to that
first stage in the infancy of language, to which
the introductory paragraphs in Mr Smith’s dis¬
course are exclusively confined.
Note GG, p. 138.
“ Je viens de recevoir une lettre d’un Prince
Regnant de I’Empire, ou S. A. me marque avoir
vu deux fois ce printems a la derniere foire de
Leipsig, et examine avec soin un chien qui
parle. Ce chien a prononce distinctement plus
de trente mots, repondant meme assez a propos
a son maitre : il a aussi prononce tout 1’alpha-
bet excepte les lettres m, n, x.”—(Leib. Opera,
Tom. V. p. 72.)
Thus far tire fact rests upon the authority of
the German prince alone. But from a passage
in the History of the Academy of Sciences, for the
year 1706, it appears that Leibnitz had himself
seen and heard the dog. What follows is trans¬
cribed from a report of the Academy upon a
letter from Leibnitz to the Abbe de St Pierre,
giving the details of this extraordinary occur¬
rence.
<c Sans un garant tel que M. Leibnitz, temoin
oculaire, nous n’aurions pas la hardiesse de rap-
porter, qu’aupres de Zeitz dans la Misnie, il y a
un chien qui parle. C’est un chien de Paysan,
d’une figure des plus communes, et de grandeur
mediocre. Un jeune enfant lui entendit pousser
quelques sons qu’il crut ressembler a des mots
Allemands, et sur cela se mit en tete de lui ap-
prendre a parler. Le maitre, qui n’avoit rien de
mieux a faire, n’y epargna pas le terns ni ses
peines, et heureusement le disciple avoit des dis¬
positions qu’il eut etc difficile de trouver dans un
autre. Enfin, au bout de quelques annees, le
chien s^ut prononcer environ une trentaine de
mots: de ce nombre sont The, Caffe, Chocolat,
Assemblee, mots Francois, qui ont passe dans
VAllemand tels qu’ils sont II est a remarquer,
que le chien avoit bien trois ans quand il fut mis Notes
a 1’ecole. Il ne parle que par echo, c’est a dire, I]lus^ion}.
apres que son maitre a prononce un mot; et il v
semble, qu’il ne repete que par force et malgre
lui, quoiqu’on ne le maltraite pas. Encore une
fois, M. Leibnitz 1’a vu et entendu.”
(Expose d’une lettre de M. Leibnitz a I’Abbe
de St Pierre sur un chien qui parle.) “ Get
expose de la lettre de M. Leibnitz se trouve dans
1’Histoire de 1’Academic des Sciences, annee
1706. Ce sont les Auteurs de 1’Histoire de
I’Academiequi parlent.”—(Leib. Opera,\o\. II.
p. 180. P. II.)
May not all the circumstances of the above
story be accounted for, by supposing the master
of the dog to have possessed that peculiar species
of imitative power which is called Ventriloquism ?
Mathews, I have no doubt, would find little
difficulty in managing such a deception, so as
to impose on the senses of any person who had
never before witnessed any exhibition of the same
kind.
Note H H, p. 138.
When I speak in favourable terms of the
Philosophical Spirit, I hope none of my readers
will confound it with the spirit of that false
philosophy, which, by unhinging every rational
principle of belief, seldom fails to unite in the
same characters the extremes of scepticism and
of credulity. It is a very remarkable fact, that
the same period of the eighteenth century, and
the same part of Europe which were most dis¬
tinguished by the triumphs of Atheism and
Materialism, were also distinguished by a greater
number of visionaries and impostors than had
ever appeared before, since the revival of letters.
Nor were these follies confined to persons of
little education. They extended to men of the
highest rank, and to many individuals of dis¬
tinguished talents. Of this the most satisfactory
proofs might be produced ; but I have room here
only for one short quotation. It is from the pen
of the Due de Levis, and relates to the celebrat¬
ed Marescbal de Richelieu, on whom Voltaire
lias lavished so much of his flattery. “ Ce dont
je suis positivement certain, c’est que cet homme
spirituel (Le Mareschal de Richelieu) etoit
262
PRELIMINARY DISSERTATIONS.
Notes superstitieux, et qu’il croyoit aux predictions
ustrations ^es astrologues et autres sottises de cet espece.
Je 1’ai vu refusant a Versailles d’aller faire sa
cour au fils aine de Louis XVI. en disant seri-
eusement, qu’il savoitque cet enfant n’etoit point
destine au trdne. Cette credulite superstitieuse,
general e pendant la ligue, etoit encore tres com¬
mune sous la regence lorsque le Due de Richelieu
entra dans le monde; par la plus bizarre des
inconsequences, elle s’allioit tres bien avec la
plus grande impiete, et la plupart des material-
istes croyoient aux esprits; aujourd’hui, ce genre
de folie est tres rare; mais beaucoup de gens,
qui se moquent des astrologues, croient a des
predictions d’une autre espece.”—[Souvenirs et
Portraits, par M. de Levis, a Paris, 1813.)
Some extraordinary facts of the same kind are
mentioned in the Memoirs of the Marquis de
BouiUe. According to him, Frederic the Great
himself was not free from this sort of superstition.
A similar remark is made by an ancient
historian, with respect to the manners of Rome
at the period of the Gothic invasion. 46 There
are many who do not presume either to bathe,
or to dine, or to appear in public, till they have
diligently consulted, according to the rules of
astrology, the situation of Mercury, and the
aspect of the Moon. It is singular enough that
this vain credulity may often be discovered
among the prophane sceptics, who impiously
doubt or deny the existence of a Celestial
Power.”—(Gibbon, from Ammianus Marcel-
linus, Decline and Fall of the Roman Empire,
Vol. V. p. 278.)
Note 11, p. 139
The following estimate of Leibnitz, considered
in comparison with his most distinguished con¬
temporaries, approaches, on the whole, very
nearly to the truth; although some doubts may
he entertained about the justness of the decision
in the last clause of the sentence. 44 Leibnitz,
aussi hardi que Descartes, aussi subtil que
Bayle, peut-etre moins profond que Newton, et
moins sage que Locke, mais seul universel entre Notes
to us ces grand hommes, paroit avoir embrasse i]iUSt^ions
le domaine de la raison dans toute son etendue,
et avoir contribue le plus a repandre cet esprit
philosophique que fait aujourd’hui la gloire de
notre siecle.”—(Bailey, Ebgede Leibnitz.)
I have mentioned in the text only a part of
the learned labours of Leibnitz. It remains to
he added, that he wrote also on various subjects
connected with chemistry, medicine, botany,
and natural history; on the philosophy and lan¬
guage of the Chinese; and on numberless other
topics of subordinate importance. The philolo¬
gical discussions and etymological collections,
which occupy so large a space among his works,
would (even if he had produced nothing else)
have been no inconsiderable memorials of the
activity and industry of his mind.
Manifold and heterogeneous as these pursuits
may at first appear, it is not difficult to trace the
thread by which his cariosity was led from one
of them to another. I have already remarked a
connection of the same sort between his different
metaphysical and theological researches; and it
may not be altogether uninteresting to extend
the observation to some of the subjects enume-
xated in the foregoing paragraph.
The studies by which he first distinguished
himself in the learned world (I pass over that
of jurisprudence,1 which was imposed on him
by the profession for which he was destined)
were directed to the antiquities of his own coun¬
try; and more particularly to those connected
with the history of the house of Brunswick.
With this view he ransacked, with an unex¬
ampled industry, the libraries, monasteries, and
other archives, both of Germany and of Italy;
employing in this ungrateful drudgery several
of the best and most precious years of his life.
Mortified, however, to find how narrow the li¬
mits are, within which the range of written re¬
cords is confined, he struck out for himself and
1 Bailly, in his Eloge on Leibnitz, speaks of him in terms of the most enthusiastic praise, as a philosophical jurist, and as
a man fitted to become the legislatoi of the human race* lo me, I must own, it appears, that there is no part of his
writings in which he discovers less of his characteristical originality, than where he professes to treat of the law of nature!
On these occasions, how inferior does he appear to Grotius, not to speak of Montesquieu and his disciples !
DISSERTATION FIRST.
263
Notes his successors a new and unexpected light, to
111 trations them through the seemingly hopeless
darkness of remote ages. This light was the
study of etymology, and of the affinities of dif¬
ferent tongues in their primitive roots;—a light
at first faint and glimmering, hut which, since
his time, has continued to increase in bright¬
ness, and is likely to do so more and more as
* the world grows older. It is pleasing to see his
curiosity on this subject expand, from the names
of the towns and rivers and mountains in his
neighbourhood, till it reached to China and other
regions in the east; leading him, in the last re¬
sult, to some general conclusions concerning the
origin of the different tribes of our species, ap¬
proximating very nearly to those which have
been since drawn from a much more extensive
range of data by Sir William Jones, and other
philologers of the same school.
As an additional light for illustrating the an¬
tiquities of Germany, he had recourse to natu¬
ral history; examining, with a scientific eye, the
shells and other marine bodies everywhere to be
found in Europe, and the impressions of plants
and fishes (some of them unknown in this part
of the world) which are distinctly legible, even
by the unlettered observer, on many of our fos¬
sils. In entering upon this research, as well as
on the former, he seems to have had a view to
Germany alone; on the state of which (he tells
us), prior to all historical documents, it was his
purpose to prefix a discourse to his History of
the House of Brunswick. But his imagination
soon took a bolder flight, and gave birth to his
Protogo&a ;—a dissertation which (to use his own
words) had for its object “ to ascertain the ori¬
ginal face of the earth, and to collect the ves¬
tiges of its earliest history from the monuments
which nature herself has left of her successive
operations on its surface.” It is a work which,
wild and extravagant as it may now he regard- Notes
ed, is spoken of by Buffon with much respect; IUu “adtiong>
and is considered hy Cuvier as the ground-work
of Buffon’s own system on the same subject.
In the connection which I have now pointed
out between the Historical, the Philological,
and the Geological speculations of Leibnitz,
Helvetius might have fancied that he saw a new
exemplification of the law of continuity ; but the
true light in which it ought to be viewed, is as
a faithful picture of a philosophical mind eman¬
cipating itself from the trammels of local and
conventional details, and gradually rising from
subject to subject, till it embraces in its survey
those nobler inquiries which, sooner or later,
will be equally interesting to every portion of
the human race.1
Note K K, p. 143.
Of Locke’s affectionate regard for Collins
notwithstanding the contrariety of their opinions
on some questions of the highest moment, there
exist many proofs in his letters, published by M
Des Maizeaux. In one of these, the following
passage is remarkable. It is dated from Oates
in Essex, 1703, about a year before Locke’s
death.
“ You complain of a great many defects; and
that very complaint is the highest recommenda¬
tion I could desire to make me love and esteem
you, and desire your friendship. And if I were
now setting out in the world, I should think it
my great happiness to have such a companion
as you, who had a true relish for truth ; would
in earnest seek it with me ; from whom I might
receive it undisguised; and to whom I might
communicate what I thought true freely. Be¬
lieve it, my good friend, to love truth for truth’s
sake, is the principal part of human perfection
1 In the above note, I have said nothing of Leibnitz’s project of a philosophical language, founded on an alphabet of
Human Thoughts, as he has nowhere given us any hint of the principles on which he intended to proceed in its formation,
although he has frequently alluded to "the practicability of such an invention in terms of extraordinary confidence. (For
some remarks on these passages in his works, see Philosophy of the Hitman Mind., Yol. II. pp. 143, ei seq.) In some of
Leibnitz’s expressions on this subject, there is a striking resemblance to those of Descartes in one of his letters.—(See the
preliminary discourse prefixed to the Abbe Emery’s Pensees de Descartes, p. xiv. et seq.)
In the ingenious essay of Michaelis On the Influence of Opinions on Language, and of Language on Opinions (which obtained
the prize from the Royal Society of Berlin in 1759, there are some very acute and judicious reflections on the impossibili¬
ty of carrying into effect, with any advantage, such a project as these philosophers had in view. The author’s argument
on this point seems to me decisive, in the present state of human knowledge; but who can pretend to fix a limit to the
possible attainments of our posterity !
264
PRELIMINARY DISSERTATIONS.
Notes in this world, and the seed-plot of all other vir-
Illimrations ^ues ’ an^:’ ^ mistake not, you have as much
of it as ever I met with in any body. What,
then, is there wanting to make you equal to the
best; a friend for any one to be proud of ? ’
 The whole of Locke’s letters to Col¬
lins are highly interesting and curious; more
particularly that which he desired to be deliver¬
ed to him after his own death. From the ge¬
neral tenor of these letters, it may be inferred,
that Collins had never let Locke fully into the
secret of those pernicious opinions which he was
afterwards at so much pains to disseminate.
Note L L, p. 144.
In addition to the account of Spinoza given in
Bayle, some interesting particulars of his his¬
tory may be learnt from a small volume, en¬
titled, La Vie de B. de Spinoza, tiree des ecrits
de ce Fameux Philosophe, et du temoignage de plu-
sieurs personnes dignes de foi, qui Vont connu par-
ticulierement: par Jean Colerus, Ministre de
VEglise Lutherienne de la Haye. 1706.1 The
book is evidently written by a man altogether
unfit to appi’eciate the merits or demerits of
Spinoza as an author; but it is not without
some value to those who delight in the study of
human character, as it supplies some chasms in
the narrative of Bayle, and has every appear¬
ance of the most perfect impartiality and can¬
dour.
According to this account, Spinoza was a per¬
son of the most quiet and inoffensive manners; of
singular temperance and moderation in his pas¬
sions; contented and happy with an income
which barely supplied him with the necessaries
of life; and of too independent a spirit to accept
of any addition to it, either from the favour of
princes, or the liberality of his friends. In con¬
formity to the law, and to the customs of his
ancestors (which he adhered to, when he thought
them not unreasonable, even when under the
sentence of excommunication), he resolved to
learn some mechanical trade; and fortunately
selected that of grinding optical glasses, in which
he acquired so much dexterity, that it furnished Notes
him with what he conceived to be a sufficient xiiustrat;on8
maintenance. He acquired also enough of the
art of designing, to produce good portraits in
chalk and china-ink, of some distinguished
persons.
For the last five years of his life he lodged in
the house of a respectable and religious family,
who were tenderly attached to him, and from
whom his biographer collected various interest¬
ing anecdotes. All of them are very credit¬
able to his private character, and more particu¬
larly show how courteous and amiable he must
have been in his intercourse with his inferiors.
In a bill presented for payment after his death,
he is styled by Abraham Keveling, his barber-
surgeon, Benedict Spinoza, of blessed memory;
and the same compliment is paid to him by
the tradesman who furnished gloves to the
mourners at his funeral.
These particulars are the more deserving of
notice, as they rest on the authority of a very
zealous member of the Lutheran communion,
and coincide exactly with the account given of
Spinoza by the learned and candid Mosheim.
“ This man (says he) observed, in his conduct,
the rules of wisdom and probity much better
than many who profess themselves Christians;
nor did he ever endeavour to pervert the senti¬
ments or to corrupt the morals of those with
whom he lived; or to inspire, in his discourse,
a contempt of religion or virtue.” [Eccles.
History, translated by Dr Maclaine, Vol. IV.
p. 252.)
Among the various circumstances connected
with Spinoza’s domestic habits, Colerus men¬
tions one very trifling singularity, which ap¬
pears to me to throw a strong light on his ge¬
neral character, and to furnish some apology
for his eccentricities as an author. The ex¬
treme feebleness of his constitution (for he was
consumptive from the age of 20) having unfitted
him for the enjoyment of convivial pleasures,
he spent the greater part of the day in his
chamber alone; but when fatigued'with study,
he would sometimes join the family party below,
1 The Life of Spinoza by Colerus, with some other curious pieces on the same subject, is reprinted in the complete edi¬
tion of Spinoza’s Works, published at Jena, in 1802.
DISSERTATION FIRST.
265
Notes and take a part in their conversation, however
. and. insignificant its suhiect might he. One of the
Illustrations. » °
amusements with which he was accustomed to
unbend his mind, was that of entangling flies
in a spider’s web, or of setting spiders a-fight-
ing with each other; on which occasions (it is
added) he would observe their combats with so
much interest, that it was not unusual for him
to he seized with immoderate fits of laughter.
Does not this slight trait indicate very decidedly
a tendency to insanity; a supposition by no
means incompatible (as will he readily admitted
by all who have paid any attention to the phe¬
nomena of madness) with that logical acumen
which is so conspicuous in some of his writ¬
ings ?
His irreligious principles he is supposed to
have adopted, in the first instance, from his
Latin preceptor Vander Ende, a physician and
classical scholar of some eminence; hut it is
much more probable, that his chief school of
atheism was the synagogue of Amsterdam;
where, without any breach of charity, a large
proportion of the more opulent class of the as¬
sembly may he reasonably presumed to belong
to the ancient sect of Sadducees. (This is, I
presume, the idea of Heineccius in the followr-
ing passage: “ Quamvis Spinoza Cartesii prin-
cipia methodo mathematica demon strata dede-
rit; Pantheismum tamen ille non ex Cartesio
didicit, sed domi habuit, quos sequeretur” In
proof of this, he refers to a book entitled Spi-
nozismus in Judaismo, by Waechterus.) The
blasphemous curses pronounced upon him in
the sentence of excommunication were not well
calculated to recal him to the faith of his ances¬
tors; and when combined with his early and
hereditary prejudices against Christianity, may
go far to account for the indiscriminate war
which he afterwards waged against priests of
all denominations.
The ruling passion of Spinoza seems to have
been the love of fame. “It is owned (says
Bayle) that he had an extreme desire to immor¬
talise his name, and would have sacrificed his
life to that glory, though he should have been Notes
torn to pieces by the mob.”—(Art. Spinoza.) iiius^jons
Note MM, p. 148.
In proof of the impossibility of Liberty, Col¬
lins argues thus:
“ A second reason to prove man a necessary
agent is, because all his actions have a begin¬
ning. For whatever has a beginning must have
a cause; and every cause is a necessary cause.
“ If anything can have a beginning, which
has no cause, then nothing can produce some¬
thing. And if nothing can produce something,
then the world might have had a beginning
without a cause; which is an absurdity not only
charged on atheists, but is a real absurdity in
itself.* * * * *Liberty, therefore, or a power to
act or not to act, to do this or another thing
under the same causes, is an impossibility and
atheistical.1
“ And as Liberty stands, and can only be
grounded on the absurd principles of Epicurean
atheism; so the Epicurean atheists, who were
the most popular and most numerous sect of the
atheists of antiquity, were the great assertors of
liberty; as, on the other side, the Stoics, who
were the most popular and numerous sect
among the religionaries of antiquity, were the
great assertors of fate and necessity.”—(Col¬
lins, p. 54.)
As to the above reasoning of Collins, it can¬
not he expected that I should, in the compass of
a Note, “ hoult this matter to the bran.” It is
sufficient here to remark, that it derives all its
plausibility from the unqualified terms in which
the maxim (/A^ev uminov) has frequently been
stated. “ In the idea of every change (says Dr
Price, a zealous advocate for the freedom of the
will) is included that of its being an effect.”
(Review, fyc. p. 30, 3d edition.) If this maxim
he literally admitted without any explanation or
restriction, it seems difficult to resist the con¬
clusions of the Necessitarians. The proper
statement of Price’s maxim evidently is, that
1 To the same purpose Edwards attempts to show, that “ the scheme of free-will (by affording an exception to that dic¬
tate of common sense which refers every event to a cause) would destroy the proof a posteriori for the being of God.”
DISS. I. PART II. 2 L
266
preliminary dissertations.
Notes “ in every change we perceive in inanimate mat-
... and. ter, the idea of its being an effect is necessarily
involvedand that he himself understood it
under this limitation appears clearly from the
application he makes of it to the point in dis¬
pute. As to intelligent and active beings, to
affirm that they possess the power of self-deter¬
mination, seems to me to he little more than an
identical proposition. Upon an accurate analysis
of the meaning of words, it will he found that
the idea of an efficient cause implies the idea
of Mind; and, consequently, that it is absurd
to ascribe the volitions of mind to the efficiency
of causes foreign to itself. To do so must un¬
avoidably involve us in the inconsistencies of
Spinozism; by forcing us to conclude that
everything is passive, and nothing active in the
universe; and, consequently, that the idea of a
First Cause involves an impossibility.—But upon
these hints I must not enlarge at present; and
shall, therefore, confine myself to what falls
more immediately within the scope of this Dis¬
course, Collins’s Historical Statement with re¬
spect to the tenets of the Epicureans and the
Stoics.
In confirmation of his assertion concerning
the former, he refers to the following well known
lines of Lucretius:
Denique si semper motus connectitur omnis,
&c. &c. (Lucret. Lib. 2. v. 251.;
On the obscurity of this passage, and the in¬
consistencies involved in it, much might be
said; but it is of more importance, on the pre¬
sent occasion, to remark its complete repug¬
nance to the whole strain and spirit of the Epi¬
curean Philosophy. This repugnance did not
escape the notice of Cicero, who justly consi¬
ders Epicurus as having contributed more to
establish, by this puerile subterfuge, the autho¬
rity of Fatalism, than if he had left the argu¬
ment altogether untouched. “ Nec vero quis-
qnam magis con firm are mild videtur non modo
fatum, verum etiam necessitatem et vim om¬
nium rerum, sustulisseque motus animi volun¬
taries, quam hie qui aliter obsistere fato fatetur
se non potuisse nisi ad has commenticias decli-
nationes confugisset.”—(Liber de Fato, cap. 20.)
On the noted expression of Lucretius (fatis Notes
avolsa voluntas) some acute remarks are made Illus^ldions
in a note on the French translation by M. de la
Grange. They are not improbably from the
pen of the Baron d’Holbach, who is said to have
contributed many notes to this translation.
Whoever the author was, he was evidently
strongly struck with the inconsistency of this
particular tenet with the general principles of
the Epicurean system.
“ On est surpris qu’ Epicure fonde la liberte
humaine sur la declinaison des atomes. On de-
mande si cette d6clinaison est necessaire, ou si
elle est simplement accidentelle. Necessaire,
comment la liberte peut elle en etre le resultat ?
Accidentelle, par quoi est elle determinee ?
Mais on devrait bien plutot etre surpris, qu’il
lui soit venu en idee de rendre 1’homme fibre
dans un systeme qui suppose un enchainement
necessaire de causes et d’effets. C’etoit une
recherche curieuse, que la raison qui a pu faire
d’Epicure 1’Apdtre de la Liberte.” For the
theory which follows on this point, I must refer
to the work in question.—(See Traduction Nou-
velle de Lucrece, avec des Notes, par M. de la
Grange, Vol. I. pp. 218, 219, 220, a Paris,
1768.)
But whatever may have been the doctrines of
some of the ancient Atheists about man’s free-
agency, it will not be denied, that in the History
of Modern Philosophy, the schemes of Atheism
and of Necessity have been hitherto always con¬
nected together. Not that I would by any
means be understood to say, that every Neces¬
sitarian must ipso facto he an Atheist, or even
that any presumption is afforded by a man’s at¬
tachment to the former sect, of his having the
slightest bias in favour of the latter; hut only
that every modern Atheist I have heard of has
been a Necessitarian. I cannot help adding,
that the most consistent Necessitarians who
have yet appeared, have been those who follow¬
ed out their principles till they ended in Spino¬
zism, a doctrine which differs from atheism more
in words than in reality.
In what Collins says of the Stoics in the above
quotation, he plainly proceeds on the supposi¬
tion that all Fatalists are of course Necessita-
DISSERTATION FIRST.
267
Notes rians;1 2 and I agree with him in thinking, that
Illustrations t^s wou^ ^,e case» ^ they reasoned logically.
It is certain, however, that a great proportion
of those who have belonged to the first sect have
disclaimed all connection with the second. The
Stoics themselves furnish one very remarkable
instance. I do not know any author by whom
the liberty of the will is stated in stronger and
more explicit terms, than it is by Epictetus in
the very first sentence of the Enchiridion. In¬
deed the Stoics seem, with their usual passion
for exaggeration, to have carried their ideas
about the freedom of the will to an unphiloso-
phical extreme.
If the belief of man’s free-agency has thus
maintained its ground among professed Fatalists,
it need not appear surprising, that it should have
withstood the strong arguments against it, which
the doctrine of the eternal decrees of God, and
even that of the Divine prescience, appear at
first sight to furnish. A remarkable instance of
this occurs in St Augustine (distinguished in ec¬
clesiastical history by the title of the Doctor of
Gracej, who has asserted the liberty of the will
in terms as explicit as those in which he has an¬
nounced the theological dogmas with which it is
most difficult to reconcile it. Nay, he has gone
so far as to acknowledge the essential import¬
ance of this belief, as a motive to virtuous con¬
duct. u Quocirca nullo modo cogimur, aut re-
tenta praescientia Dei, tollere voluntatis arbi-
trium, aut retento voluntatis arbitrio, Deum,
quod nefas est, negare praescium futurorum, sed
utrumque amplectimur, utrumque fideliter et
veraciter confitemur : illud, ut bene credamus ;
hoc ut bene vivamus.,,
Descartes has expressed himself on this point
nearly to the same purpose with St Augustine.
In one passage he asserts, in the most unquali¬
fied terms, that God is the cause of all the ac¬
tions which depend on the Free-will of Man ;
and yet, that the Will is really free, he consi- Notes
ders as a fact perfectly established by the evi-Illus^ati0ns
dence of consciousness. {t Sed quemadmodum
existentiae divinae cognitio non debet liberi nos-
tri arbitrii certitudinem tollere, quia illud in no-
bismet ipsis experimur et sentimus; ita neque
liberi nostri arbitrii cognitio existentiam Dei
apud nos dubiam facere debeb In depen den tia
enim ilia quam experimur, atque in nobis per-
sentiscimus, et quae actionibus nostris laude vel
vituperio dignis efficiendis sufficit, non pugnat
cum dependentia alterius generis, secundum
quam omnia Deo subjiciuntur.”—(Cartesii
Epistoloe, Epist. VIII. IX. Pars i.) These let¬
ters form part of his correspondence with the
Princess Elizabeth, daughter of Frederick, King
of Bohemia, and Elector Palatine.
We are told by Dr Priestley, in the very in¬
teresting Memoirs of his own Life, that he was
educated in the strict principles of Calvinism;
and yet it would appear, that while he remained
a Calvinist, he entertained no doubt of his being
a free-agent. “ The doctrine of Necessity,” he
also tells us, “ he first learned from Collins ; *
and was established in the belief of it by Hart¬
ley’s Observations on Man.”—(Ibid. p. 19.) He
farther mentions in another work, that 44 he was
not a ready convert to the doctrine of Necessity,
and that, like Dr Hartley himself, he gave up
his liberty with great reluctance.”—{Preface to
the Doctrine of Philosophical Necessity Illustrated,
2d edit. Birmingham, 1782, p. xxvii.)
These instances afford a proof, I do not say of
the compatibility of man’s free-agency with those
schemes with which it seems most at variance,
but of this compatibility in the opinion of some
of the profoundest thinkers who have turned
their attention to the argument. No conclusion,
therefore, can be drawn against a man’s belief
in his own free-agency, from his embracing other
metaphysical or theological tenets, with which
1 Collins states this more strongly in what he says of the Pharisees. “ The Pharisees, who were a religious sect, as¬
cribed all things to fate or to God’s appointment, and it was the first article of their creed, that Fate and God do all, and,
consequently, they could not assert a true liberty when they asserted a liberty together with this fatality and necessity of all
things.”—(Collins, p. 54.)
2 We are elsewhere informed by Priestley, that “it was in consequence of reading and studying the Inquiry of Collins,
he was first convinced of the truth of the doctrine of Necessity, and was enabled to see the fallacy of most of the arguments
m favour of Philosophical Liberty: though (he adds) I was much more confirmed in this principle by my acquaintance
with Hartley’s Theory of the Human Mind: a work to which I owe much more than I am able to express.”—(Preface, &c.
&c. p. xxvii.)
268
preliminary dissertations.
Notes it may appear to ourselves impossible to recon-
and •!
Illustrations. C1^e 1 '
power of the mind to obey without constraint Note*
the impulse of the motives which act upon it*”mustrati0ns.
This definition, which is obviously the same in
substance with that of Hobbes, is thus very just-
As for the notion of liberty, for which Collins ly, as well as acutely, animadverted on by Cuvier,
professes himself an advocate, it is precisely that “ N’admettant aucune action sans motif, comme
of his predecessor Hobbes, who defines a free- dit-il, il n’y a aucun effet sans cause, Bonnet
ao-ent to be, “ he that can do if he will, and for- definit la liberte imrale le pouvoir de Tame de
bear if he will.”—(Hobbes’s Works, p. 484, fob suivre sans contrainte les motifs dont elleeprouve
ed.) The same definition has been adopted by I’impulsion; et resout ainsi les objections que
Leibnitz, by Gravesande, by Edwards, by Bon- Ton tire de la provision de Dieu; mais peut-
net, and by all our later necessitarians. It can- etre aussi detournent-t-il 1’idee qu’on se fait
not" be better expressed than in the words of d’ordinaire de la liberte. Malgre ces opinions
Gravesande : “ JFacultas faciendi quod libuerit, que touch ent au Materialisme et au Fatalisme,
qucecunque fuerit voluntatis determination—(In- Bonnet fut tres religieux.” (Biographic Uni-
trod. ad Philosoph. § 115.) verselle, a Paris, 1812. Art. Bonnet)
Dr Priestley ascribes this peculiar notion of From this passage it appears, that the very
free-will to Hobbes as its author;1 but it is, in ingenious writer was as completely aware as
fact, of much older date even among modern Clarke or Reid, of the unsoundness of the defi-
metaphysicians ; coinciding exactly with the nition of nwral liberty given by Hobbes and his
doctrine of those scholastic divines who contend- followers; and that the ultimate tendency of the
ed for the Liberty of Spontaneity, in opposition doctrine which limits the free-agency of man to
to the Liberty of Indifference. It is, however, to (what has been called) the liberty of spontaneity,
Hobbes that the partizans of this opinion are in- was the same, though in a more disguised form,
debted for the happiest and most popular illus- with that of fatalism.
tration of it that has yet been given. “ I con- For a complete exposure of the futility of this
ceive,” says he, “ liberty to be rightly defined, definition of liberty, as the word is employed in
The absence of all the impediments to action that the controversy about man’s free-agency, I have
are not contained in the nature and intrinsical only to refer to Clarke’s remarks on Collins, and
quality of the agent. As, for example, the wa- to Dr Reid’s Essays on the Active Powers of Man.
ter is said to descend freely, or to have liberty In this last work, the various meanings of this
to descend by the channel of the river, because very ambiguous word are explained with great
there is no impediment that way: but not across, accuracy and clearness.
because the banks are impediments. And, The only two opinions which, in the actual
though water cannot ascend, yet men never say, state of metaphysical science, ought to be stated
it wants the liberty to ascend, but the faculty or in contrast, are that of Liberty (or free-will) on
power, because the impediment is in the nature the one side, and that of Necessity on the other,
of the water, and intrinsical. So also we say, As to the Liberty of Spontaneity (which expresses
he that is tied wants the liberty to go, because a fact altogether foreign to the point in question),
the impediment is not in him, but in his hands; I can conceive no motive for inventing such a
whereas we say not so of him who is sick or phrase, but a desire in some writers to veil the
lame, because the impediment is in himself.”— scheme of necessity from their readers, undei a
(Treatise of Liberty and Necessity.) language less revolting to the sentiments ot
According to Bonnet, “ moral liberty is the mankind ; and, in others, an anxiety to banish
DISSERTATION FIRST.
269
Notes it as far as possible from their own thoughts,
and. bv substituting: instead of the terms in which
Illustrations. J ° . . .
it is commonly expressed, a circumlocution
which seems, on a superficial view, to concede
something to the advocates for liberty.
If this phrase (the Liberty of Spontaneity)
should fall into disuse, the other phrase (the
Liberty of Indifference),1 which is commonly
stated in opposition to it, would become com¬
pletely useless; nor would there be occasion for
qualifying with any epithet, the older, simpler,
and much more intelligible word, Free-will.
The distinction between physical and moral
necessity I conceive to be not less frivolous than
those to which the foregoing animadversions
relate. Or this point I agree with Diderot,
that the word necessity (as it ought to be under¬
stood in this dispute) admits but of one interpre¬
tation.
Note N N, p. 148.
To the arguments of Collins, against man’s
free-agency, some of his successors have added,
the inconsistency of this doctrine with the known
effects of education (under which phrase they com¬
prehend the moral effects of all the external cir¬
cumstances in which men are involuntarily
placed) in forming the characters of individuals.
The plausibility of this argument (on which
much stress has been laid by Priestley and others)
arises entirely from the mixture of truth which
it involves; or, to express myself more correctly,
from the evidence and importance of ihefact on
which it proceeds, when that fact is stated with
due limitations.
That the influence of education, in this com¬
prehensive sense of the word, was greatly under¬
rated by our ancestors, is now universally ac¬
knowledged ; and it is to Locke’s writings,
more than to any other single cause, that the
change in public opinion on this head is to be
ascribed. On various occasions, he has ex¬
pressed himself very strongly with respect to
the extent of this influence ; and has more than
once intimated his belief, that the great majori¬
ty of men continue through life what early edu- Notes
cation had made them. In making use, how- Illusat"atic
ever, of this strong language, his object (as is
evident from the opinions which he has avowed
in other parts of his works) was only to arrest the
attention of his readers to the practical lessons
he was anxious to inculcate; and not to state a
metaphysical fact which was to be literally and
rigorously interpreted in the controversy about
liberty and necessity. The only sound and
useful moral to be drawn from the spirit of his
observations, is the duty of gratitude to Heaven
for all the blessings, in respect of education and
of external situation, which have fallen to ou<
own lot; the impossibility of ascertaining the
involuntary misfortunes by which the seeming
demerits of others may have been in part occa¬
sioned, and in the same proportion diminished;
and the consequent obligation upon ourselves,
to think as charitably as possible of their con¬
duct, under the most unfavourable appearances.
The truth of all this I conceive to be implied in
these words of Scripture, “ To whom much is
given, of him much will be required;” and, if
possible, still more explicitly and impressively,
in the parable of the Talents.
Is not the use which has been made by Ne¬
cessitarians of Locke’s Treatise on Education,
and other books of a similar tendency, only one
instance more of that disposition, so common
among metaphysical Sciolists, to appropriate to
themselves the conclusions of their wiser and
more sober predecessors, under the startling
and imposing disguise of universal maxims, ad¬
mitting neither of exception nor restriction ? It
is thus that Locke’s judicious and refined re¬
marks on the Association of Ideas have been ex¬
aggerated to such an extreme in the coarse cari¬
catures of Hartley and of Priestley, as to bring,
among cautious inquirers, some degree of dis¬
credit on one of the most important doctrines
of modern philosophy. Or, to take another
case still more in point; it is thus that Locke’s
reflections on the effects of education in modify¬
ing the intellectual faculties, and (where skil¬
fully conducted) in supplying their original
1 Both phrases are favourite expressions with Lord Karnes in his discussions on this subject. See in particular the Ap.
pendix to his Essay on Liberty and Necessity, in the last edition of his Essays on Morality and Natural Religion.
270
PRELIMINARY DISSERTATIONS.
Notes defects, have beeti distorted into the puerile
Illustrations. Para^ox of Helvetius, that the mental capacities
of the whole human race are the same at the
moment of hirth. It is sufficient for me here
to throw out these hints, which will he found
to apply equally to a large proportion of other
theories started hy modern metaphysicians.
Before I finish this note, I cannot refrain
from remarking, with respect to the argument
for Necessity drawn from the Divine prescience,
that, if it he conclusive, it only affords an addi¬
tional confirmation of what Clarke has said
concerning the identity of the creed of the Ne¬
cessitarians with that of the Spinozists. For, if
God certainly foresees all the future volitions
of his creatures, he must, for the same reason,
foresee all his own future volitions; and if this
knowledge infers a necessity of volition in the
one case, how is it possible to avoid the same
inference in the other ?
Note OO, p. 149.
A similar application of St Paul’s comparison
of the potter is to be found both in Hobbes and
in Collins. Also, in a note annexed hy Cowley
to his ode entitled Destiny; an ode written (as
we are informed hy the author) “ upon an ex¬
travagant supposition of two angels playing a
game at chess; which, if they did, the specta¬
tors would have reason as much to believe that
the pieces moved thpmselves, as we have for
thinking the same of mankind, when we see
them exercise so many and so different actions.
It was of old said by Plautus, Dii nos quasi pilas
homines habent, “ We are hut tennis-balls for
the gods to play withal,” which they strike
away at last, and still call for new ones; and
St Paul says, “ We are but the clay in the hand
of the potter”
For the comparison of the potter, alluded to
by these different writers, see the epistle to the
Romans, chap. ix. verses 18, 19, 20, 21. Upon
these verses the only comment which I have to
offer is a remark of the apostle Peter* that “ In
the epistles of our beloved brother Paul are
some things hard to he understood, which they
that are unlearned and unstable wrest unto their
own destruction.”
The same similitude of the potter makes a con- Notes
spicuous figure in the writings of Hobbes, who iiiust"adtiong
has availed himself of this, as of many other in-
sulated passages of Holy Writ, in support of
principles which are now universally allowed
to strike at the very root of religion and mora¬
lity. The veneration of Cowley for Hobbes is
well known, and is recorded hy himself in the
ode which immediately precedes that on Des¬
tiny. It cannot, however, he candidly supposed,
that Cowley understood the whole drift of
Hobbes’ doctrines. The contrary, indeed, in
the present instance, is obvious from the ode
before us; for while Cowley supposed the angels
to move, like chess-men, the inhabitants of this
globe, Hobbes (along with Spinoza) plainly
conceived that the angels themselves, and even
that Being to which he impiously gave the name
of God, were all of them moved, like knights
and pawns, by the invisible hand of fate or ne¬
cessity.
Were it not for the serious and pensive cast
of Cowley’s mind, and his solemn appeal to the
authority of the apostle, in support of the doc¬
trine of destiny, one would be tempted to con¬
sider the first stanzas of this ode in the light of
a jeu d’esprit, introductory to the very charac-
teristical and interesting picture of himself,
with which the poem concludes.
Note PP, p. 150.
“ Tout ce qui est doit etre, par cela meme
que cela est. Voila la seule bonne philosophic.
Aussi longtemps que nous ne connaitrons pas
cet univers, comme on dit dans 1’ecole, a priori,
tout est necessite. La liberte est un mot vide
de sens, comme vous allez voir dans la lettre de
M. Diderot.”—{Lettre de Grimm au Due de
Saxe-Gotha.)
<c C’est ici, mon cher, que je vais quitter le
ton de predicateur pour prendre, si je peux,
celui de philosophe. Regardez-y de pres, et
vous verrez que le mot liberte est un mot vide
de sens; qu’il n’y a point, et qu’il ne peut y
avoir d’etres fibres; que nous ne sommes que
ce qui convient a 1’ordre general, a 1’organisa¬
tion, a 1’education, et a la chaine des evenemens.
Voila ce qui dispose de nous invinciblement.
DISSERTATION FIRST.
271
Notes
and
On ne conceit non plus qu’un etre agisse sans
Illustrations qu’un des bras d’une balance agisse sans
Taction d’un poids, et le motif nous est toujours
exterieur, etranger, attache ou par une nature
ou par une cause quelconque, qui n’est pas nous.
Ce qui nous trompe, e’est la prodigieuse variete
de nos actions, jointe a Thabitude que nous
avons prise tout en naissant, de confondre le
volontaire avec le libre. Nous avons tant loue,
tant repris, nous Tavons ete tant de fois, que
e’est un prejuge bien vieux que celui de croire
que nous et les autres voulons, agissons libre-
ment. Mais s’il n’y a point de liberte, il n’y a
point d’action qui merite la louange ou le blame;
il n’y a ni vice, ni vertu, rien dont il faille re-
compenser ou chatier. Qu’est ce qui distingue
done les hommes ? La bienfaisance ou la mal-
faisance. Le malfaisant est un homme qu’il
faut detruire et non punir; la bienfaisance est
une bonne fortune, et non une vertu. Mais
quoique 1’homme bien ou malfaisant ne soit pas
libre, Thomme n’en est pas moins un etre qu’on
modifie; e’est par cette raison qu’il faut detruire
le malfaisant sur une place publique. De la les
bons effets de 1’exemple, des discours, de Tedu-
cation, du plaisir, de la douleur, des grandeurs,
de la misere, &c.; de la un sorte de philosophic
pleine de commiseration, qui attache fortement
aux hons, qui n’irrite non plus centre le mechant,
que centre un ouragan qui nous remplit les yeux
de poussiere. Il n’y a qu’une sorte de causes a
proprement parler; ce sont les causes physiques.
Il n’y a qu’une sorte de necessite, e’est la meme
pour tous les etres. Voila ce qui me reconcilie
avec le genre humain; e’est pour cette raison
que je vous exhortais a la philanthropie. Adop-
tez ces principes si vous les trouvez bons, ou
montrez-moi qu’ils sont mauvais. Si vous les
adoptez, ils vous reconcilieront aussi avec les
autres et avec vous-meme; vous ne vous saurez
ni bon ni mauvais gre d’etre ce qui vous etes.
Ne rien reprocher aux autres, ne se repentir de
rien; voila les premiers pas vers la sagesse. Ce
qui est hors de la est prejuge, fausse philo-
sophie.”—fCorrespmdance Litteraire, Philoso-
phique, et Critique, addressee au Due de Saxe-
Gotha, par le Baron De Grimm et par Dide- Note*
rot. Premiere Partie, Tom. I. pp. 300, 304, iiiUStrnations<
305, 306, Londres, 1814.)
Note Q Q, p. 156.
See in Bayle the three articles Luther, Knox,
and Buchanan. The following passage concern-.
ing Knox may serve as a specimen of the others.
It is quoted by Bayle from the Cosmographie
Universelle of The vet, a writer who has long
sunk into the contempt he merited, but whose
zeal for legitimacy and the Catholic faith raised
him to the dignity of almoner to Catherine de
Medicis, and of historiographer to the King of
France. I borrow the translation from the Eng¬
lish Historical Dictionary.
u During that time the Scots never left Eng¬
land in peace; it was when Henry VIII. played
his pranks with the chalices, relics, and other
ornaments of the English churches; which tra¬
gedies and plays have been acted in our time in
the kingdom of Scotland, by the exhortations of
Noptz,1 the first Scots minister of the bloody
Gospel. This firebrand of sedition could not be
content with barely following the steps of Lu¬
ther, or of his master, Calvin, who had not long
before delivered him from the gallies of the
Prior of Capua, where he had been three years
for his crimes, unlawful amours, and abominable
fornications; for he used to lead a dissolute life,
in shameful and odious places, and had been
also found guilty of the parricide and murder
committed on the body of the Archbishop of St
Andrew’s, by the contrivances of the Earl of
Rophol, of James Lescle, John Lescle, their
uncle, and William du Coy. This simonist, who
had been a priest of our church, being fattened
by the benefices he had enjoyed, sold them for
ready money; and finding that he could not
make his cause good, he gave himself up to the
most terrible blasphemies. He persuaded also
several devout wives and religious virgins to
abandon themselves to wicked adulterers. Nor
was this all. During two whole years, he never
ceased to rouse the people, encouraging them to
1 Thus Thevet (says Bayle) writes the name of Knox.
272
preliminary dissertations.
Notes take up arms against the Queen, and to drive
and. her out of the kingdom, which he said was
Illustrations, electee, ag it had been formerly in the time of
heathenism The Luthexans have
churches and oratories. Their ministers sing
psalms, and say mass; and though it be different
from ours, yet they add to it the Creed, and
• other prayers, as we do. And when their mi¬
nisters officiate, they wear the cope, the cha¬
suble, and the surplice, as ours do, being con¬
cerned for their salvation, and careful of what
relates to the public worship. Whereas the
Scots have lived these twelve years past without
laws, without religion, without ceremonies, con¬
stantly refusing to own a King or a Queen, as
so many brutes, suffering themselves to he im¬
posed upon by the stories told them by this
arch-hypocrite Noptz, a traitor to God and to
his country, rather than to follow the pure Gos¬
pel, the councils, and the doctrine of so many
holy doctors, both Greek and Latin, of the Ca¬
tholic church.”
If any of my readers be yet unacquainted with
the real character and history of this distin¬
guished person, it may amuse them to compare
the above passage with the very able, authentic,
and animated account of his life, lately pub¬
lished by the reverend and learned Dr M‘Crie.
Note R R, p. 161.
Dr Blair, whose estimate of the distinguishing
beauties and imperfections of Addison’s style
reflects honour on the justness and discernment
of his taste, has allowed himself to he carried
along much too easily, by the vulgar sneers at
Addison’s want of philosophical depth. In one
of his lectures on rhetoric he has even gone so
far as to accuse Addison of misapprehending,
or, at least, of mis-stating^ Locke’s doctrine con¬
cerning secondary qualities. But a comparison
of Dr Blair’s own statement with that which he
censures, will not turn out to the advantage of
the learned critic; and I willingly lay hold of
this example, as the point at issue turns on one
of the most refined questions of metaphysics.
The words of Addison are these:—
“ Things would make hut a poor appearance
to the eye, if we saw them only in their proper
figures and motions. And what reason can we Notes
assign for their exciting in us many of those Illus^ions
ideas which are different from anything that ex-
ists in the objects themselves (for such are light
and colours), were it not to add supernumerary
ornaments to the universe, and make it more
agreeable to the imagination?”
After quoting this sentence, Dr Blair proceeds
thus:—
“ Our author is now entering on a theory,
which he is about to illustrate, if not with much
philosophical accuracy, yet with great beauty of
fancy and glow of expression. A strong in¬
stance of his want of accuracy appears in the
manner in which he opens the subject. For
what meaning is there in things exciting in us
many of those ideas which are different from any¬
thing that exists in the objects ? No one, sure,
ever imagined that our ideas exist in the objects.
Ideas, it is agreed on all hands, can exist no¬
where hut in the mind. What Mr Locke’s phi¬
losophy teaches, and what our author should
have said, is, exciting in us many ideas of qualities
which are different from anything that exists in the
objects.”
Let us now attend to Locke’s theory, as
stated by himself:—
“ From whence I think it is easy to draw
this observation, That the ideas of primary qua¬
lities of bodies are resemblances of them, and
their patterns do really exist in the bodies them¬
selves, but the ideas produced in us by these
secondary qualities have no resemblance of them
at all. There is nothing like our ideas existing
in the bodies themselves. They are in the
bodies we denominate from them, only a power
to produce these sensations in us. And what
is sweet, blue, or warm in idea, is hut the cer¬
tain hulk, figure, and motion of the insensible
parts in the bodies themselves, which we call
so.”
The inaccuracy of Locke in conceiving that
our ideas of primary qualities are resemblances
of these qualities, and that the patterns of such
ideas exist in the bodies themselves, has been
fully exposed by Dr Reid. But the repetition of
Locke’s inaccuracy (supposing Addison to have
been really guilty of it) should not be charged
upon him as a deviation from his master’s doc-
DISSERTATION FIRST.
273
trine. To all, however, who understand the
subject, it must appear evident, that Addison
has, in this instance, improved greatly on Locke,
by keeping out of view what is most exception¬
able in his language, while he has retained all
that is solid in his doctrine. For my own part,
I do not see how Addison’s expressions could be
altered to the better, except, perhaps, by substi¬
tuting the words unlike to, instead of different
from. But in this last phrase, Addison has been
implicitly followed by Dr Blair, and certainly
would not have been disavowed as an interpre¬
ter by Locke himself. Let me add, that Dr
Blair’s proposed emendation (“ exciting in us
many ideas of qualities, which are different
from any thing that exists in the objects”), if
not wholly unintelligible, deviates much farther
from Locke’s meaning than the correspondent
clause in its original state. The additional
words of qualities throw an obscurity over the
whole proposition, which was before sufficiently
precise and perspicuous.1 * * * * * *
My principal reason for offering these remarks
in vindication of Addison’s account of secondary
qualities was, to prepare the way for the sequel
of the passage animadverted on by Dr Blair.
“We are everywhere entertained with pleas¬
ing shows and apparitions. We discover imagi¬
nary glories in the heavens and in the earth, and
see some of this visionary beauty poured out
upon the whole creation. But what a rough
unsightly sketch of nature should we be enter¬
tained with, did all her colouring disappear, and
the several distinctions of light and shade
vanish ?8 In short, our souls are delightfully
lost and bewildered in a pleasing delusion, and
vye walk about like the enchanted hero of a
romance, who sees beautiful castles, woods, and Notes
meadows, and, at the same time, hears the 1]lus^lions>
warbling of birds and the purling of streams;
but, upon the finishing of some secret spell, the
fantastic scene breaks up, and the disconsolate
knight finds himself on a barren heath, or in a
solitary desert.”
In this passage one is at a loss whether most
to admire the author’s depth and refinement of
thought, or the singular felicity of fancy dis¬
played in its illustration. The image of the
enchanted hero is so unexpected, and, at the same
time, so exquisitely appropriate, that it seems
itself to have been conj ured up by an enchanter’s
wand. Though introduced with the unpretend¬
ing simplicity of a poetical simile, it has the
effect of shedding the light of day on one of the
darkest corners of metaphysics. Nor is the
language in which it is conveyed unworthy of
the attention of the critic; abounding through¬
out with those natural and happy graces, which
appear artless and easy to all but to those who
have attempted to copy them.
The praise which I have bestowed on Addison
as a commentator on this part of Locke’s Essay
will not appear extravagant to those who may
take the trouble to compare the conciseness and
elegance of the foregoing extracts with the pro¬
lixity and homeliness of the author’s text. (See
Locke’s Essay, Book II. chap. viii. §§ 17, 18.)
It is sufficient to mention here, that his chief
illustration is taken from “ the effects of manna
on the stomach and guts.”
Note S S, p. 168.
For the following note I am indebted to my
1 Another passage, afterwards quoted by Dr Blair, might have satisfied him of the clearness and accuracy of Addison’s
ideas on the subject.
“ I have here supposed that my reader is acquainted with that great modern discovery, which is, at present, universally
acknowledged by all the inquirers into Natural Philosophy; namely, that light and colours, as apprehended by the imagination.
are only ideas in the mind, and not qualities that have any existence in matter. As this is a truth which has been proved
incontestibly by many modern philosophers, if the English reader would see the notion explained at large, he may find it
in the eighth book of Mr Locke’s Essay on Human Understanding."
I have already taken notice (Elements of the Philosophy of the Human Mind. Vol. I. Note P.) of the extraordinary precision
of the above statement, arising from the clause printed in Italics. By a strange slip of memory I ascribed the merit of this
very judicious qualification, not to Addison, but to Dr Akenside, who transcribed it from the Spectator.
The last quotation affords me also an opportunity of remarking the correctness of Addison’s information about the his¬
tory of this doctrine, which most English writers have conceived to be an original speculation of Locke?s. From some of
Addison’s expressions, it is more than probable, that he had derived his first knowledge of it from Malebranche.
* On the supposition made in this sentence, the face of Nature, instead of presenting a “ rough unsightly sketch,” would,
it is. evident, become wholly invisible. But I need scarcely say, this does not render Mr Addison’s allusion less pertinent.
DISS. I. PART II. 2 M
274
PRELIMINARY DISSERTATIONS.
Notes learned friend Sir William Hamilton, Professor
Illustrations. Universal History in the University of Edin-
burgh.
« The Clavis Universalis of Arthur Collier,
though little known in England, has been trans¬
lated into German. It is published in a work
entitled “ Samlung” &c. &c. literally, “ A Col¬
lection of the most distinguished Authors who
deny the existence of their own bodies, and of
the whole material world,—containing the
dialogues of Berkeley, between Hylas and Phi-
lonous, and Collier’s Universal Key translated,
with Illustrative Observations, and an Appendix,
wherein the existence of Body is demonstrated,
by John Christopher Eschenhach, Professor of
Philosophy in Rostock.” (Rostock, 1756, 8vo.)
The remarks are numerous, and show much
reading. The Appendix contains, 1. An ex¬
position of the opinion of the Idealists, with its
grounds and arguments 2. A proof of the
external existence of body. The argument on
which he chiefly dwells to show the existence of
matter is the same with that of Hr Reid, in so
far as he says, “ a direct proof must not here he
expected; in regard to the fundamental prin
ciples of human nature, this is seldom possible, or
rather is absolutely impossible.” He argues at
length, that the Idealist has no better proof of the
existence of his soul than of the existence of his
body; “ when an Idealist says, lama thinking being;
of this I am certain from internal conviction ;—I
would ask from whence he derives this certainty,
and why he excludes from this conviction the possi¬
bility of deception ? He has no other answer than
this, I feel it. It is impossible that I can have any
representation of self without the consciousness of
being a thinking being. In the same manner,
Eschenhach argues that the feeling applies to the
existence of body, and that the ground of belief
is equally strong and conclusive, in respect to
the reality of the objective^ as of the subjective,
in perception.”
Note TT, p. 182.
“And yet Diderot, in some of his lucid intervals,
seems to have thought and felt very differently.”
The following passage (extracted from his
Pensees Philosophiques) is pronounced by La
Harpe to he not only one of the most eloquent Notes
which Diderot has written, but to be one of the illustrations,
best comments which is any where to be found
on the Cartesian argument for the existence of
God. It has certainly great merit in point of
reasoning; but I cannot see with what propriety
it can be considered as a comment upon the ar¬
gument of Descartes; nor am I sure if, in point
of eloquence, it be as well suited to the English
as to the French taste.
“ Convenez qu’il y auroit de la folie a refuser
a vos semblables la faculte de penser. Sans
doute, mais que s’ensuit-il de la? 11 s’ensuit,
que si 1’univers, que dis-je 1’univers, si I’aile
d’un papillon m’offre des traces mille fois plus
distinctes d’une intelligence que vous n’avez
d’indices que votre semblable a la faculte de
penser, il est mille fois plus fou de nier qu’il
existe un Dieu, que de nier que votre semblable
pense. Or, que cela soit ainsi, c’est a vos lu-
mieres, c’est a votre conscience que j’en appelle.
Avez-vous jamais remarque dans les raisonne-
mens, les actions, et la conduite de quel que
homme que ce soit, plus d’intelligence, d’ordre,
de sagacite, de consequence, que dans le meca-
nisme d’un insecte ? La divinite n’est elle pas
aussi clairement empreinte dans I’ceil d’un ciron,
que la faculte de penser dans les Merits du grand
Newton ? Quoi ! le monde forme prouverait
moins d’intelligence, que le monde explique?
Quelle assertion! I’intelligence d’un premier
etre ne m’est pas mieux demontree par ses ou-
vrages, que la faculte de penser dans un philo-
sophe par ses ecrits? Songez done que je ne
vous objecte que I’aile d’un papillon, quand je
pourrais vous ecraser du poids de 1’univers.”
This, however, was certainly not the creed
which Diderot professed in his more advanced
years. The article, on the contrary, which im¬
mediately follows the foregoing quotation, there
is every reason to think, expresses his real sen¬
timents on the subject. I transcribe it at length,
as it states clearly and explicitly the same argu¬
ment which is indirectly hinted at in a late pub¬
lication by a far more illustrious author.
“ J’ouvre les cahiers d’un philosophe eelebre,
et je lis : 4 Athees, je vous accorde que le mouve-
ment est essentiel a la matiere ; qu’en concluez-
vous ? que le monde resulte du jet fortuit d’a-
DISSERTATION FIRST.
275
Notes tomes ? J’aimerois autant que vous me dissiez
and oue 1’Iliade d’Homere ou la Henriade de Vol-
Illustrations.
taire est un resultat de jets lortmts de carac-
teres ?’ Je me garderai bien de faire ce raisonne-
ment a un athee. Cette comparaison lui don-
neroit beau jeu. Selon les lois de I’analyse des
sorts, me diroit-il, je ne doit etre surpris qu’une
chose arrive, lorsqu’elle est possible, et que la
difficulte de revenement est compensee par la
quantite des jets. II y a tels nombre de coups
dans lesquels je gagerois avec avantage d’amener
cent mille six a la fois avec cent mille des.
Quelle que fut la somme finie de caracteres
avec laquelle on me proposeroit d’engendrer
fortuitement 1’Iliade, il y a telle somme finie
de jets qui me rendroit la proposition avanta-
geuse; mon avantage seroit meme infini, si la
quantite de jets accordee etoit infinie,” &c. &c.
—(Pensees Philosophiques, par Diderot, XXL)
My chief reason for considering this as the
genuine exposition of Diderot’s own creed is,
that he omits no opportunity of suggesting the
same train of thinking in his other works. It
may be distinctly traced in the following pas¬
sage of his Traite du Beau, the substance of
which he has also introduced in the article
Beau of the Encyclopedie.
“ Le beau n’est pas toujours 1’ouvrage d’une
cause intelligente; le mouvement etablit souvent,
soit dans un etre considere solitairement, soit
entre plusieurs etres compares entr’eux, une
multitude prodigieuse de rapports surprenans.
Les cabinets d’histoire naturelle en offrent un
grand nombre d’exemples. Les rapports sont
alors des resultats de combinaisons fortuites, du
moins par rapport a nous. La nature imite en
se jouant, dans cent occasions, les productions Notes
d’art; et Ton pourroit demander, je ne dis pasIlluSjrnadioi|S
si ce philosophe qui fut jete par une tempete
sur les bords d’une He inconnue, avoit raison
de se crier, a la vue de quelque figures de geo¬
metric ; e Courage, mes amis, void des pas
d’hommes ;’ mais combien il faudroit remarquer
de rapports dans un etre, pour avoir une certi¬
tude complete qu’il est 1’ouvrage d’un artiste1 2
(en quelle occasion, un seul defaut de symme¬
tric prouveroit plus que toute somme donnee de
rapports); comment sont entr’eux le temps de
faction de la cause fortuite, et les rapports ob¬
serves dans les effets produits ; et si (a 1’excep-
tion des oeuvres du Tout-Puissant)* il y a des
cas ou le nombre des rapports ne puisse jamais
etre compense par celui des jets.”
With respect to the passages here extracted
from Diderot, it is worthy of observation, that
if the atheistical argument from chances be con¬
clusive in its application to that order of things
which we behold, it is not less conclusive when
applied to every other possible combination of
atoms which imagination can conceive, and
affords a mathematical proof, that the fables of
Grecian mythology, the tales of the genii, and
the dreams of the Rosicrusians, may, or rather
must, all of them, be somewhere or other rea¬
lized in the infinite extent of the universe: a
proposition which, if true, would destroy every
argument for or against any given system of
opinions founded on the reasonableness or the
unreasonableness of the tenets involved in it;
and would, of consequence, lead to the subver¬
sion of the whole frame of the human under¬
standing. 3
1 Is not this precisely the sophistical mode of questioning known among Logicians by the name of Sorites or Acervus ?
“ Vitiosum sane,” says Cicero, “ et captiosum genus.”—(Acad. Qucest. Lib. IV. xvi.)
2 To those who enter fully into the spirit of the foregoing reasoning, it is unnecessary to observe, that this parenthetical
clause is nothing better than an ironical salvo. If the argument proves any thing, it leads to this general conclusion, that
the apparent order of the universe affords no evidence whatever of the existence of a designing cause.
* The atheistical argument here quoted from Diderot is, at least, as old as the time of Epicurus.
Nam certe neque consilio primordia rerum
Ordine se quaeque, atque sagaci mente locarunt
Nec quos quaeque darent motus pepigere profecto;
Sed quia multimodis, multis, mutata, per omne
Ex infinito vexantur percita plagis,
Omne genus motus, et coetus experiundo,
Tandem deveniunt in taleis disposituras,
Qualibus haec rebus consistit summa creata—(Ltjcret. Lib. I. 1. 1020.)
And still more explicitly in the following lines :
Nam cum respicias immensi temporis omne
Praeteritum spatium; turn motus materialis
Multimadi quam sint; facile hoc adcredere possis,
Semina saepe in eodem, ut nunc sunt, ordine posta.—(Ibid. Lib. III. 1. 867.)
276
preliminary dissertations.
Notes Mr Hume, in his Natural History of Religion
Illustrations. (Sect. XI.), has drawn an inference from the
internal evidence of the Heathen Mythology, in
favour of the supposition that it may not be al¬
together so fabulous as is commonly supposed.
« The whole mythological system is so natural,
that in the vast variety of planets and worlds
contained in this universe, it seems more than
probable, that somewhere or other it is really
carried into execution.” The argument of Di¬
derot goes much farther, and leads to an exten¬
sion of Mr Hume’s conclusion to all conceivable
systems, whether natural or not.
But further, since the human mind, and all
the numberless displays of wisdom and of power
which it has exhibited, are ultimately to he re¬
ferred to a fortuitous concourse of atoms, why
might not the Supreme Being, such as we are
commonly taught to regard him, have been
Himself (as well as the Gods of Epicurus)J the
result of the continued operation of the same
blind causes ? or rather, must not such a Being
have necessarily resulted from these causes ope¬
rating from all eternity, through the immensity
of space ?—a conclusion, by the way, which, ac¬
cording to Diderot’s own principles, would lead
us to refer the era of his origin to a period inde¬
finitely more remote than any given point of
time which imagination can assign; or, in other
words, to a period to which the epithet eternal
may with perfect propriety he applied. The
amount, therefore, of the whole matter is this,
that the atheistical reasoning, as stated by Di¬
derot, leaves the subject of natural, and, I may
add, of revealed religion, precisely on the same
footing as before, without invalidating, in the
very smallest degree, the evidence for any one
of the doctrines connected with either; nay
more, superadding to this evidence, a mathema¬
tical demonstration of the possible truth of all
those articles of belief which it was the ob¬
ject of Diderot to subvert from their founda¬
tion.
It might be easily shown, that these prin¬
ciples, if pushed to their legitimate consequences,
instead of establishing the just authority of rea¬
son in our constitution, would lead to the most Notes
unlimited credulity on all subjects whatever; illustrations,
or (what is only another name for the same
thing) to that state of mind, which, in the words
of Mr Hume, “ does not consider any one pro¬
position as more certain, or even as more pro¬
bable, than another.”
The following curious and (in my opinion)
instructive anecdote has a sufficient connection
with the subject of this note, to justify me in
subjoining it to the foregoing observations. I
transcribe it from the Notes annexed to the
Abbe de Lille’s poem entitled La Conversation.
(A Paris, 1812.)
“ Dans la societe du Baron d’Holbach, Dide¬
rot proposa un jour de nommer un avocat de
Dieu, et on choisit 1’Abbe Galiani. II s’assit et
debuta ainsi:
“ Un jour a Naples, un homme de la Basili-
cate prit devant nous, six des dans un cornet,
et paria d’amener rafle de six. Je dis cette
chance etoit possible. II I’amena sur le champ
une seconde fois; je dis la meme chose. 11 re¬
mit les des dans le cornet trois, quatre, cinq
fois, et toujours rafle de six. Sangue di Bacco,
m’ecriai-je, les des sontpipes ; et ils 1’etoient.
“ Philosophes, quand je considere Fordre
toujours renaissant de la nature, ses lois immu-
ables, ses revolutions toujours constantes dans
une variete infinie; cette chance unique et con-
servatrice d’un univers tel que nous le voyons,
qui revient sans cesse, malgre cent autres mil¬
lions de chances de perturbation et de destruc¬
tion possibles, je m’eerie: certes la nature est
pipee!”
The argument here stated strikes me as irre¬
sistible ; nor ought it at all to weaken its effect,
that it was spoken by the mouth of the Abbe
Galiani.
Whatever his own professed principles may
have been, this theory of the loaded die appears
evidently, from the repeated allusions to it in
his familiar correspondence, to have produced a
very deep impression on his mind.—(See Corre-
spondance inedite de 1’Abbe Galiani, &c. Vol. I.
pp. 18, 42, 141, 142, a Paris, 1818.)
1 Cic. de Nat. Dear. Lib. I. XXIV.
DISSERTATION FIRST.
As the old argument of the atomical atheists
is plainly that on which the school of Diderot
are still disposed to rest the strength of their
cause, I shall make no apology for the length of
this note. The sceptical suggestions on the same
subject which occur in Mr Hume’s Essay on the
Idea of Necessary Connection, and which have
given occasion to so much discussion in this
country, do not seem to me to have ever pro¬
duced any considerable impression on the French
philosophers.
Note U U, p. 182.
Among flie contemporaries of Diderot, the
author of the Spirit of Laws is entitled to parti¬
cular notice, for the respect with which he al¬
ways speaks of natural religion. A remarkable
instance of this occurs in a letter to Dr War-
burton, occasioned by the publication of his
View of Bolingbrokds Philosophy. The letter, it
must be owned, savours somewhat of the politi¬
cal religionist; but how fortunate would it have
been for France, if, during its late revolutionary
governments, such sentiments as those here ex¬
pressed by Montesquieu had been more gene¬
rally prevalent among his countrymen ! “ Celui
qui attaque la religion revelee n’attaque que la re¬
ligion re velee; mais celui qui attaque la religion
naturelleattaquetouteslesreligionsdumonde....
II n’est pas impossible d’attaquer une religion
revelee, parce qu’elle existe par des faits parti-
culiers, et que les faits par leur nature peuvent
etre une matiere de dispute; mais il n’en est
pas de meme de la religion naturelle; elle est
tiree de la nature de I’homme, dont on ne pent
pas disputer encore. J’ajoute a ceci, quel peut
etre le motif d’attaquer la religion revelee en
Angleterre ? On l’y a tellement purge de tout
prejuge destructeur qu’elle n’y peut faire de mal
et qu’elle y peut faire, au contraire, une infinite
de biens. Je sais, qu’un homme en Espagne ou
en Portugal que 1’on va bruler, ou qui craint
d’etre brule, parce qu’il ne croit point de cer¬
tains articles dependans ou non de la religion
revelee, a un juste sujet de 1’attaquer, parce
qu’il peut avoir quelque esperance de pourvoir a
sa defense naturelle: mais il n’en est pas de
meme en Angleterre, ou tout homme qui attaque
la religion revel^e 1’attaque sans interet, et ou
cet homme, quand il reussiroit, quand meme
il auroit raison dans le fond, ne feroit que de-
truire une infinite de biens pratiques, pour
6tablir une verite purement speculative.”—(For
the whole letter, see the 4to edit, of Montes¬
quieu’s Works. Paris, 1788. Tome V. p. 391.
Also Warburton’s Works by Hurd, Vol. VII. p.
553. London, 1758.)
In the foregoing passage, Montesquieu hints
more explicitly than could well have been ex¬
pected from a French magistrate, at a considera¬
tion which ought always to be taken into the
account, in judging of the works of his country¬
men, when they touch on the subject of reli¬
gion ; I mean, the corrupted and intolerant
spirit of that system of faith which is imme¬
diately before their eyes. The eulogy bestowed
on the church of England is particularly deserv¬
ing of notice, and should serve as a caution to
Protestant writers against making common
cause with the defenders of the church of Rome.
With respect to Voltaire, who, amidst all his
extravagancies and impieties, is well known to
have declared open war against the principles
maintained in the Systeme de la Nature, it is re¬
marked by Madame de Stael, that two different
epochs may be distinguished in his literary life ;
the one, while his mind was warm from the
philosophical lessons he had imbibed in Eng¬
land ; the other, after it became infected with
those extravagant principles which, soon after
his death, brought a temporary reproach on the
name of Philosophy. As the observation is ex¬
tended by the very ingenious writer to the
French nation ki general, and draws a line be¬
tween two classes of authors who are frequently
confounded together in this country, I shall
transcribe it in her own words.
“ Il me semble qu’on pourroit marquer dans
le dix-huitieme siecle, en France, deux epoques
parfaitement distinctes, celle dans laquelle 1’in-
fluence de 1’Angleterre s’est fait sentir, et celle
ou les esprits se sont precipites dans la destruc¬
tion : Alors les lumieres se sont changees en in-
cendie, et la philosophie, magicifinne irritee, a
consume le palais ou elle avoit etale ses pro-
diges.
M En politique, Montesquieu appartient a la
278
PRELIMINARY DISSERTATIONS.
Notes premiere epoque, Raynal a la seconde ; en reli-
and. trion, les ecrits de Voltaire, qui avoit la tolerance
pour but, sont inspires par 1 espnt ae la pie
miere moitie du siecle, mais sa miserable et
vaniteuse ireligion a fl6tri la seconde.”—
VAUemagne, Tome III. pp- 37, 38.)
Nothing, in truth, can be more striking than
the contrast between the spirit of Voltaire’s ear¬
ly and of his later productions. From the for¬
mer may he quoted some of the suhlimest sen¬
timents anywhere to he found, both of religion
and of morality. In some of the latter, he appears
irrecoverably sunk in the abyss of fatalism.
Examples of both are so numerous, that one is
at a loss in the selection. In making choice of
the following, I am guided chiefly by the com¬
parative shortness of the passages.
‘‘ Consulte Zoroastre et Minos, et Solon,
Et le sage Socrate, et le grand Ciceron :
Ils ont adore' tons un maitre, un juge, un pere;—
Ge systeme sublime a Thomme est ne'cessaire.
C’est le sacrd lien de la society,
Le premier fondement de la sainte e'quitd ;
Le frein du see'ldrat, 1’esperance du juste.
Si les cieux, depouillds de leur empreinte auguste,
Pouvoient cesser jamais de le manifester.
Si Dieu n’existoit pas, il faudroit I’inventer.”1
Nor is it only on this fundamental principle
of religion that Voltaire, in his better days, de¬
lighted to enlarge. The existence of a natural
law engraved on the human heart, and the li¬
berty of the human will, are subjects which he
has repeatedly enforced and adorned with all
his philosophical and poetical powers. What
can be more explicit, or more forcible, than the
following exposition of the inconsistencies of
fatalism ?
“ Yois de la liberty cet ennemi mutin,
Aveugle partisan d’un aveugle destin;
Entends comme il consulte, approuve, ou ddlibdre,
Entends de quel reproche il couvre un adversaire,
Yois comment d’un rival il cherche a se venger, Notes
Comme il punit son fils, et le veut corriger. and
Il le croyoit done fibre ?_Oui sans doute, et lui-meme ^®*rations.
Dement k chaque pas son funeste systeme.
Il mentoit a son coeur, en voulant expliquer
Ce dogme absurde a croire, absurde a pratiquer.
Il reconnoit en lui le sentiment qu’il brave,
Il agit comme fibre et parle comme esclave.”2
This very system, however, which Voltaire
has here so severely reprobated, he lived to avow
as the creed of his more advanced years. The
words, indeed, are put into the mouth of a fic¬
titious personage ; hut it is plain, that the writer
meant to he understood as speaking his own
sentiments. “ Je vois une chaine immense,
dont tout est chainon; elle embrasse, elle serre
aujourd’hui la nature,” &c. &c.
“ Je suis done ramene malgre moi a cette
ancienne id6e, que je vois etre la base de tous
les systemes, dans laquelle tous les philosophes
retomhent apres mille detours, et qui m est de-
montre par toutes les actions des hommes, par
les miennes, par tous les evenemens que j ai lus,
que j’ai vus, et aux-quelles j’ai eu part; c est le
Fatalisme, c’est la Necessity dont je vous ai deja
parle.”—(Lettres de Memmius d Ciceron. See
CEuvres de Voltaire, Melanges, Tome IV. p.
358. 4to. Edit. Geneve, 1771.)
“ En effet” (says Voltaire, in another of his
pieces), il seroit bien singulier que toute la na¬
ture, tous les astres, oheissent a des lois eter-
nelles, et qu’il y eut un petit animal haut de
cinq pieds, qui au mepris de ces lois put agir
toujours comme il lui plairoit au seul gre de son
caprice.”
.... .To this passage Voltaire adds the fol¬
lowing acknowledgment:—“ L’ignorant qui
pense ainsi n’a pas toujours pense de meme,5
mais il est enfin contraint de se rendre.”—(Le
Philosophe Ignorant.)
Notwithstanding, however, this change in
1 A thought approaching very nearly to this occurs in one of Tillotson’s Sermons. “ The being of God is so comfortable,
so convenient, so necessary to the felicity of mankind, that (as Tully admirably says) Dii immortales ad tisum hommum faln-
eati pene videantur If God were not a necessary being of himself, he might almost be saul to be made for the use a
benefit of Man.” For some ingenious remarks on this quotation from Cicero, see Jortin s Tracts., Voi. 1. p. .yl.
2 These verses form a part of a Discourse on the Liberty of Man; and the rest of the poem is in the same strain., e s.°
very imperfectly did Yoltaire even then understand the metaphysical argument on this subject, that he prefixed to is
Discourse the following advertisement. “ On entend par ce mot liberte, le pouvoir de faire ce qu’on veut. Il n y a, et ne
neut v avoir d’autre YihcrtL" It appears, therefore, that in maintaining the liberty of spontaneity, Voltaire conceived himselt
to be combating the scheme of Necessity; whereas this sort of liberty, no Necessitarian or Fatalist was ever hardy enoug
to dispute-Qf of this he refers t0 his Treatise 0f Metaphysics, written forty years before, for the use of Madame du Chatelet,
DISSERTATION FIRST.
279
Notes Voltaire’s philosophical opinions, he continued
and to the last his zealous opposition to atheism.1
But in what respects it is more pernicious than
fatalism, it is not easy to discover.
A reflection of La Harpe’s, occasioned by
some strictures of Voltaire’s upon Montesquieu,
applies with equal force to the numberless in¬
consistencies which occur in his metaphysical
speculations: “ Les ohjets de meditation etoient
trop etrangers a Texcessive vivacite de son esprit.
Saisir fortement par Timagination les ohjets
qu’elle ne doit montrer que d’un cote, c’est ce
qui est du Poete; les embrasser sous toutes les
faces, c’est ce qui est du Philosophe, et Vol¬
taire etoit trop exclusivement Tun pour etre
1’autre.”—(Cours de Litterat. Tome XV. pp.
46, 47.)
A late author2 has very justly reprobated
that spiritual deification of nature which has been
long fashionable among the French, and which,
according to his own account, is at present not
unfashionable in Germany. It is proper, how¬
ever, to observe, that this mode of speaking has
been used by two very ditferent classes of wri¬
ters ; by the one with an intention to keep as
much as possible the Deity out of their view,
while studying his works; by the other, as a
convenient and well understood metaphor, by
means of which the frequent and irreverent
mention of the name of God is avoided in philo¬
sophical arguments. It was with this last view,
undoubtedly, that it was so often employed by
Newton, and other English philosophers of the
same school. In general, when we find a wri¬
ter speaking of the wise or of the benevolent in¬
tentions of nature, we should be slow in imput¬
ing to him any leaning towards atheism. Many
of the finest instances of Final Causes, it is cer¬
tain, which the eighteenth century has brought
to light, have been first remarked by inquirers
who seem to have been fond of this phraseology;
and of these inquirers, it is possible that some
would have been less forward in bearing testi¬
mony to the truth, had they been forced to avail
themselves of the style of theologians. These
speculations, therefore, concerning the intentions Notes
or designs of Nature, how reprehensible soever illustrations,
and even absurd in point of strict logic the lan-
guage may be in which they are expressed, may
often be, nay, have often been, a step towards
something higher and better ; and, at any rate,
are of a character totally different from the blind
chance of the Epicureans, or the conflicting
principles of the Manicheans
Note X X, p. 195.
“ In the attempt, indeed, which Kant has made
to enumerate the general ideas which are not de¬
rived from experience, but arise out of the pure un¬
derstanding, Kant may well lay claim to the praise
of originalityy The object of this problem is
thus stated by his friend, Mr Schulze, the au¬
thor of the Synopsis formerly quoted. (The fol¬
lowing translation is by Dr Willich, Elements,
&c. p. 45.)
“ To investigate the whole store of original
notions discoverable in our understanding, and
which lie at the foundation of all our knowledge;
and at the same time to authenticate their true
descent, by showing that they are not derived
from experience, but are pure productions of the
understanding.
“ 1. The perceptions of objects contain, in¬
deed, the matter of knowledge, but are in them¬
selves blind and dead, and not knowledge; and
our soul is merely passive in regard to them.
« 2. If these perceptions are to furnish know¬
ledge, the understanding must think of them,
and this is possible only through notions (con¬
ceptions), which are the peculiar form of our
understanding, in the same manner as space and
time are the form of our sensitive faculty.
“ 3. These notions are active representations
of our understanding-faculty; and as they re¬
gard immediately the perceptions of objects, they
refer to the objects themselves only mediately.
“ 4. They lie in our understanding as pure
notions a priori, at the foundation of all our
knowledge. They are necessary forms, radical
1 See the Diet. Philosophique, Art. Atheisms. See also the Strictures on the Systems ds la Nature in the Questions sur VEn-
cyclopedie; the very work from which the above quotation is taken.
2 Frederick Schlegel. Lectures on the History of Literature. Vol. II. p. 169. Edinburgh, loo.
280
PRELIMINARY DISSERTATIONS.
Notes
and
Illustrations.
notions, categories (predicaments), of which all
our knowledge of them must be compounded:
And the table of them follows.
“ Quantity ; unity, plurality, totality.
“ Quality ; reality, negation, limitation.
“ Relation ; substance, cause, reciprocation.
“ Modality ; possibility, existence, necessity.
“ 5. Now, to think and to judge is the same
thing; consequently, every notion contains a
particular form of judgment concerning objects.
There are four principal genera of judgments :
They are derived from the above four possible
functions of the understanding, each of which
contains under it three species ; namely, with re¬
spect to
“ Quantity, they are universal, particular, sin¬
gular judgments.
“ Quality, they are affirmative, negative, in¬
finite judgments.
<c Relation, they are categorical, hypothetical,
disjunctive judgments.
44 Modality, they are problematical, assertory,
apodictical judgments.”
These tables speak for themselves without
any comment.
Note YY, p. 195.
Kant’s notions of Time are contained in the
following seven propositions : 1. Idea temporis
non oritur sed supponitur a sensibus. 2. Idea tem¬
poris est singular is, non generalis. Tempus enim
quodlibet non cogitatur, nisi tanquam pars unius
ejusdem temporis immensi. 3. Idea itaque tem¬
poris est intuitus, et quoniam ante omnem sensa-
tionem concipitur, tanquam conditio respectuum
in sensibilibus obviorum, est intuitus, non sen-
sualis, sed purus. 4. Tempus est quantum conti¬
nuum et legum continui in mutationibus universi
principium. 5. Tempus non est objectivum aliquid
etreale, nec substantia, necaccidens, necrelatio, sed
subjectiva conditio, per naturam mentis humanse
necessaria, quaelibet sensibilia, certa lege sibi co-
ordinandi, et intuitus purus. 6. Tempus est
conceptus verissimus, et, per omnia possibilia
sensuum objecta, in infinitum patens, intuitivee
repraesentationis conditio. 7. Tempus itaque est Notes
principium fonnale mundi sensibilis absolute pri- iuus^ion
mum.”
With respect to Space, Kant states a series of
similar propositions, ascribing to it very nearly
the same metaphysical attributes as to Time, and
running as far as possible a sort of parallel be¬
tween them. 44 A. Conceptus spatii non abstrahi-
tur a sensationibus externis. B. Conceptus spatii
est singularis reprcesentatio omnia in se compre-
hendens, non sub se continens notio abstracta et
communis. C. Conceptus spatii itaque est intuitus
purus; cum sit conceptus singularis; sensa¬
tionibus non conflatus, sed omnis sensationis ex-
ternae forma fundamentalis. D. Spatium non
est aliquid objectivi et realis, nec substantia,
nec accidens, nec relatio; sed subjectivum et
ideale, e natura mentis stabili lege proficiscens,
veluti schema, omnia omnino externe sensa sibi
co-ordinandi. E. Quanquam conceptus spatii,
ut objectivi alicujus et realis entis vel affectio-
nis, sit imaginarius, nihilo tamen secius respec¬
tive ad sensibilia qucecunque, non solum est ve¬
rissimus, sed et omnis veritatis in sensiuilitate
externa fundamentum.”
These propositions are extracted from a Dis¬
sertation written by Kant himself in the Latin
language.1 Their obscurity, therefore, eanno*
be ascribed to any misapprehension on the part
of a translator. It was on this account that I
thought it better to quote them in his own un¬
altered words, than to avail myself of the cor¬
responding passage in Born’s Latin version of
the Critique of Pure Reason.
To each of Kant’s propositions concerning
Time and Space I shall subjoin a short com¬
ment, following the same order in which these
propositions are arranged above.
1. That the idea of Time has no resemblance
to any of our sensations, and that it is, therefore,
not derived from sensation immediately and di¬
rectly, has been very often observed; and if
nobody had ever observed it, the fact is so very
obvious, that the enunciation of it could not en¬
title the author to the praise of much ingenuity.
Whether 44 this idea be supposed in all our sen-
1 De Mundi Sensibilis atque Intelligibilis forma et principiis. Dissertatio pro loco professionis Log. et Metaph. Ordinariae
rite sibi Yindicando ; quam exigentibus statutis Academicis publice tuebitur Immanuel Kant Itegiomonti, 1770-
DISSERTATION FIRST.
281
Notes ejations,” or (as Kant explains himself more
Illustrations. cleai'ly in *lis proposition) “ be conceived
by the mind prior to all sensation,” is a ques¬
tion which seems to me at least doubtful; nor
do I think the opinion we form concerning it a
matter of the smallest importance. One thing
is certain, that this idea is an inseparable con¬
comitant of every act of memory with respect
to past events; and that, in whatever way it is
acquired, we are irresistibly led to ascribe to
the thing itself an existence independent of the
will of any being whatever.
2. On the second proposition I have nothing
to remark. The following is the most intelli¬
gible translation of it that I can give. “ The
idea of Time is singular, not general; for any
particular length of Time can be conceived only
as a part of one and the same immense whole.”
3. From these premises (such as they are)
Kant concludes, that the idea of time is intui¬
tive ; and that this intuition, being prior to the
exercise of the senses, is not empirical but pure.
The conclusion here must necessarily partake
of the uncertainty of the premises from which
it is drawn; but the meaning of the author does
not seem to imply any very erroneous principle.
It amounts, indeed, to little more than an ex¬
planation of some of his peculiar terms.
4. That Time is a continued quantity is indis¬
putable. To the latter clause of the sentence I
can annex no meaning but this, that time enters
as an essential element into our conception of
the law of continuity, in all its various applica¬
tions to the changes that take place in Nature.
5. In this proposition Kant assumes the truth
of that much contested, and, to me, incompre¬
hensible doctrine, which denies the objective
reality of time. He seems to consider it merely
as a subjective condition, inseparably connected
with the frame of the Human Mind, in conse¬
quence of which it arranges sensible phenomena,
according to a certain law, in the order of suc¬
cession.
6. What is meant by calling Time a true con¬
ception, I do not profess to understand; nor am
I able to interpret the remainder of the sentence
in any way but this, that we can find no limits
to the range thus opened in our conceptions to
the succession of sensible events.
DISS. I. PART II.
7. The conclusion of the whole matter is, that Notes
Time is “ absolutely the first formal principle an‘1.
of the sensible world.” I can annex no mean-
ing to this ; but I have translated the original,
word for word, and shall leave my readers to
their own conjectures.
A. It appears from this, that, in the opinion
of Kant, the idea of Space is connate with the
mind, or at least, that it is prior to any infor¬
mation received from the senses. But this doc¬
trine seems to me not a little doubtful. Indeed,
I rather lean to the common theory, which sup¬
poses our first ideas of Space or Extension to be
formed by abstracting this attribute from the
other qualities of matter. The idea of Space,
howevei*, in whatever manner formed, is mani¬
festly accompanied with an irresistible convic¬
tion, that Space is necessarily existent, and that
its annihilation is impossible; nay, it appears to
me to be also accompanied with an irresistible
conviction, that Space cannot possibly be ex¬
tended in more than three dimensions. Call
either of these propositions in question, and you
open a door to universal scepticism.
B. I can extract no meaning from this, but
the nugatory proposition, that our conception of
Space leads us to consider it as the place in
which all things are comprehended.
C. “ The conception of Space, therefore, is a
pure intuition.” This follows as a necessary co¬
rollary (according to Kant’s own definition)
from Prop. A. What is to be understood by
the clause which asserts, that Space is the fun¬
damental form of every external sensation, it is
not easy to conjecture. Does it imply merely
that the conception of Space is necessarily in¬
volved in all our notions of things external ? In
this case, it only repeats over, in different and
most inaccurate terms, the last clause of Prop. B.
What can be more loose and illogical than the
phrase external sensation ?
D. That Space is neither a substance, nor an
accident, nor a relation, may be safely granted;
but does it follow from this that it is nothing
objective, or, in other words, that it is a mere
creature of the imagination ? This, however,
would seem to be the idea of Kant; and yet I
2 N
282
PRELIMINARY DISSERTATIONS.
Notes cannot reconcile it with what he says in Prop,
illustrations t^iat the conception of Space is the founda-
tion of all the truth we ascribe to our percep¬
tions of external objects. (The author’s own
words are—omnis veritatis in sensualitate ex¬
terna fundamentum I”)1 2
Upon the whole, it appears to me, that, among
these various propositions, there are some which
are quite unintelligible; that others assume, as
first principles, doctrines which have been dis¬
puted by many of our most eminent philoso¬
phers ; that others, again, seem to aim at in-
i volving plain and obvious truths in darkness
and mystery; and that not one is expressed
with simplicity and precision, which are the na¬
tural results of clear and accurate thinking. In
considering time and space as the forms of all
sensible phenomena, does Kant mean any thing
more but this,—that we necessarily refer every
sensible phenomenon to some point of space, or
to some instant of time ? If this was really his
meaning, he has only repeated over, in obscurer
language, the following propositions of Newton;
“ Ut or do partium temporis est immutabilis, sic
etiam ordo partium spatii. Moveantur hsec de
locis suis, et movebuntur (ut ita dicam) de
seipsis. Nam tempora et spatia sunt sui ipsorum
et rerum omnium quasi loca. In tempore, quoad
ordinem successionis; in spatio, quoad ordinem
situs locantur universa. De illorum essentia est
ut sint loca: et loca primaria mover! absur-
dum est.”
I have quoted this passage, not from any de¬
sire of displaying the superiority of Newton
over Kant, but chiefly to show how very nearly
the powers of the former sink to the same level
with those of the latter, when directed to inqui¬
ries unfathomable by the human faculties.
What abuse of words can be greater than to say,
That neither the parts of time nor the parts of Notes
space can be moved from their places In the iiius^‘licms_
Principia of Newton, however, this incidental
discussion is but a spot on the sun. In the
Critique of Pure Reason, it is a fair specimen of
the rest of the work, and forms one of the chief
pillars of the whole system, both metaphysical
and moral.
Note Z Z, p. 196.
The following quotation will account for the
references which I have made to Mr Nitsch
among the expounders of Kant’s Philosophy.
It will also serve to show that the Critique of
Pure Reason has still some admirers in England,
not less enthusiastic than those it had formerly
in Germany.
il In submitting this fourth Treatise on the
Philosophy of Kant to the reader” (says the
author of these articles in the Encyclopcedia
Londinensis), “ I cannot deny myself the satis¬
faction of publicly acknowledging the great as¬
sistance which I have derived in my literary pur¬
suits, from my excellent and highly valued friend
Mr Henry Richter. To him I am indebted for
the clearness and perspicuity with which the
thoughts of the immortal Kant have been con¬
veyed to the public. Indeed, his comprehensive
knowledge of the system, as well as his enthusi¬
astic admiration of its general truth, render him
a most able and desirable co-operator. Should,
therefore, any good result to mankind from our
joint labours in the display of this vast and pro¬
found system, he is justly entitled to his share
of the praise. It is with sincere pleasure that I
reflect upon that period, now two and twenty
years ago, when we first studied together under
the same master, Frederic Augustus Nitsch, who
1 Mr Nitsch has remarked this difficulty, and has attempted to remove it. “ The most essential objection (he observes)
to Kant’s system is, that it leads to scepticism; because it maintains, that the figures in which we see the external objects
clothed are not inherent in those objects, and that consequently space is something within, and not without the mind.”
(pp. 144, 145.) “ It may be further objected (he adds), that, if there be no external space, there is also no external world.
But this is concluding by far too much from these premises. If there be no external space, it will follow, that we are not
authorised to assign extension to external things, but there will follow no more.” (p. 149.) Mr Nitsch then proceeds to
obviate these objections ; but his reply is far from satisfactory, and is indeed not less applicable to the doctrine of Berkeley
than to that of Kant. This point, however, I do not mean to argue here. The concessions which Nitsch has made are
quite sufficient for my present purpose. They serve at least to satisfy my own mind, that I have not misrepresented
Kant’s-meaning _ . , , .
2 Was it not to avoid the palpable incongruity of this language that Kant was led to substitute the vtora forms instead ot
places ; the former word not seeming to be so obviously inapplicable as the latter to time and space in common ; or, to speak
more correctly, being, from its extreme vagueness, equally unmeaning when applied to both ?
DISSERTATION FIRST.
283
Notes originally imported the seeds of Transcenden-
Iiius'radons.TAL Philosophy from its native country, to
plant them in our soil; and though, as is usually
the case, many of those seeds were scattered by
the wind, I trust that a sufficient number have
taken root to maintain the growth of this vigo¬
rous and flourishing plant, till the time shall come,
when, by its general cultivation, England may
be enabled to enrich other nations with the most
perfect specimens of its produce. Professor
Nitsch, who thus bestowed upon our country her
first attainments in the department of Pure
Science, has paid the debt of nature. I confess
it is some reflection upon England, that she did
not foster and protect this immediate disciple of
the father of philosophy; but the necessities of
this learned and illustrious man unfortunately
compelled him to seek that subsistence else¬
where, which was withheld from him here. At
Rostock, about the year 1813, this valuable
member of society, and perfect master of the
philosophy he undertook to teach, entered upon
his immortal career as a reward for his earthly
services. It is with the most heartfelt satisfac¬
tion that I add my mite of praise to his revered
memory. But for him, I might ever have re¬
mained in the dark regions of sophistry and un¬
certainty.”
Note A A A, p. 201.
Among the secondary mischiefs resulting from
the temporary popularity of Kant, none is more
to be regretted than the influence of his works
on the habits, both of thinking and of writing,
of some very eminent men, who have since given
to the world histories of philosophy. That of
Tenneman in particular (a work said to possess
great merit) would appear to have been vitiated
by this unfortunate bias in the views of its
author. A very competent judge has said of it,
that <c it affords, as far as it is completed, the
most accurate, the most minute, and the most
rational view we yet possess of the different
systems of philosophy; but that the critical
philosophy being chosen as the vantage ground
from whence the survey of former systems is
taken, the continual reference in Kant’s own
language to his peculiar doctrines, renders it
frequently impossible for those who have not Notes
studied the dark works of this modern Heracli- iiius^alions
tus to understand the strictures of the historian
on the systems even of Aristotle or Plato.”
(See the article Brucker in the Encyclo-
pcedia Britannica, 7th Ed.) We are told by
the same writer, that “ among the learned of
Germany, Brucker has never enjoyed a very
distinguished reputation.” This I can very
easily credit; but I am more inclined to in¬
terpret it to the disadvantage of the German
taste, than to that of the historian. Brucker is
indeed not distinguished by any extraordinary
measure of depth or of acuteness; but in indus¬
try, fidelity, and sound judgment, he has few
superiors; qualities of infinitely greater value
in the undertaker of a historical work, than that
passion for systematical refinement, which is so
apt to betray the best-intentioned writers into
false glosses on the opinions they record.
When the above passage was written, I had
not seen the work of Buhle. I have since had
an opportunity of looking into the French trans¬
lation of it, published at Paris in 1816; and I
must frankly acknowledge, that I have seldom
met with a greater disappointment. The account
there given of the Kantian system, to which I
turned with peculiar eagerness, has, if possible,
involved to my apprehension, in additional ob¬
scurity, that mysterious doctrine. From this,
however, I did not feel myself entitled to form
an estimate of the author’s merits as a philo¬
sophical historian, till I had read some other
articles of which I considered myself better
qualified to j udge. The following short extract
will, without the aid of any comment, enable
such of my readers as know anything of the
literary history of Scotland, to form an opinion
upon this point for themselves.
“ Reid n’attaqua les systemes de ses predeces-
seurs et notamment celui de Hume, que parce
qu’il se croyait convaincu de leur defaut de
fon dement. Mais un autre antagoniste, non
moins celebre, du scepticisme de Hume, fut, en
outre, guide par la haine qu’il avoit vouee a son
illustre compatriote, lequel lux repondit avec beau-
coup d'aigreur et d’animosite. James Beattie,
284
PRELIMINARY DISSERTATIONS.
Notes professeur de morale d Edimbourg, puis ensuite, de
and. logique et de morale a TUniversite d Aberdeen,
nitrations. pr^Srerice sur Hume lorsqu'il fut question
de remplir la chaire vacante a Edimbourg. Cette
circonstancc devint sans doute la principale source
de I’inimitie que les deux savans concurent 1 un
pour 1’autre, et qui influa meme sux le ton qu ils
employerent dans les raisonnemens pax lesquels
ils se combattirent.”—(TomeV. p. 235.)
To this quotation may I be pardoned for
adding a few sentences relative to myself ?
k L’ouvi’age de Dugald Stewart, intitule. Ele¬
ments of the Philosophy of the Human Mind, est
un syncretisme des opinions de Hartley et de
Reid. Stewart borne absolument la connois-
sance, tant de fame que des choses extexieures,
a ce que le sens common nous en apprend, et
croit pouvoir ainsi mettre 1’etude de la meta¬
physique a I’abri du x’eproche de rouler sur des
choses qui depassent la sphere de notre intelli¬
gence, ou qui sont tout-a-fait inutiles dans la
pratique de la vie Les chapitres suivans
renferment le developpement du principe de
1’association des idees. Ils sont presqu entiere-
xnent eci'its d’apres Hax'tley. Stewai’t fait de-
river de ce pi’incipe toutes les facultes intellec-
tuelles et pratiques de 1’homme.”—(Tom. V.
pp. 330, 331.)
Of the discrimination displayed by Buhle in
the classification of systems and of authors, the
title prefixed to his 19th chapter may serve as
a specimen : <£ Philosophy of Condillac, of Helve-
tius, of Baron d’Holbach, of Robinet, of Bonnet,
of Montesquieu, of Burlemaqui, of Vattel, and of
Reid."
But the radical defect of Buhle’s work is, the
almost total want of references to original au¬
thors. We are presented only with the general
results of the authox*’s reading, without any
guide to assist us in confirming his conclusions
when right, or in correcting them when wrong.
This circumstance is of itself sufficient to anni¬
hilate the value of any historical composition.
Sismondi, in mentioning the history of mo¬
dern literature by Bouterwek, takes occasion to
pay a compliment (and, I have no doubt, a very
deserved one) to German scholars in general;
observing, that he has executed his task—“ avec
une etendue d’erudition, et une hyaute dans la
maniere ix en faire profiter ses lecteurs, qui Notes
semhlent propres aux savans Allemands.”— [iiUS(r'atjoni!
[He la Litt. du Midi de VEurope, Tom. I. p. 13,
a Paris, 1813.) I regret that my ignorance of
the German language has prevented me from
profiting by a woi’k of which Sismondi has ex¬
pressed so favourable an opinion ; and still
more, that the only history of philosophy from
the pen of a contemporary German scholar,
which I have had access to consult, should
form so remarkable an exception to Sismondi’s
observation.
The contents of the preceding note lay me
under the necessity, in justice to myself, of
taking some notice of the following remark, hy
an anonymous critic, on the first part of this
Dissertation, published in 1815.—(See Quarterly
Review, Vol. XVII. p. 42.)
“ In the plan which Mr Stewart has adopted,
if he has not consulted his strength, he has at
least consulted his ease ; for, supposing a per¬
son to have the requisite talent and information,
the task which our author has performed, is one
which, with the historical abstracts of Buhle or
Tenneman, cannot be supposed to have required
any very laborious meditation.”
On the insinuation contained in the foregoing
passage, I abstain from offering any comment.
I have only to say, that it was not till the
summer of 1820 that I saw the work of Buhle;
and that I have never yet had an opportunity
of seeing that of Tenneman. From what I
have found in the one, and from what I have
heard of the other, I am strongly inclined
to suspect, that when the anonymous critic
wrote the above sentence, he was not less igno¬
rant than myself of the works of these two his¬
torians. Nor can I refrain from adding (which
I do with perfect confidence), that no person
competent to judge on such a subject can read
with attention this Historical Sketch, without
perceiving that its merits and defects, whatever
they may be, are at least all my own.
Note B B B, p. 204.
Of the Scottish authors who turned their at¬
tention to metaphysical studies, pi’ior to the
DISSERTATION FIRST.
285
Note* union of the two Kingdoms, I know of none so
and. eminent as George Dal gar no of Aberdeen, au-
thor of two works, both of them strongly marked
with sound philosophy, as well as with original
genius. The one published at London, 1660,
is entitled, “ Ars signorum, vulgo character uni¬
versalis et lingua philosophica, qua poterunt ho¬
mines diversissimorum idiomatum^ spatio duarum
septimanarum, omnia animi sui sensa (in rebus
familiaribus) non minus intelligibiliter, sive scri-
bendo, sive loquendo, mutuo communicare, quam
Unguis propriis vernaculis. Prceterea, hinc etiam
poterunt juvenes, philosophice principia, et veram
logicce praxin, citius et facilius multo imbibere,
quam ex vulgaribus philosophorum scriptis.” The
other work of Dalgarno is entitled, “ Didascolo-
cophus, or the Deaf and Dumb Man’s Tutor.”
Printed at Oxford, 1680. I have given some
account of the former in the notes at the end of
the first volume of the Philosophy of the Human
Mind; and of the latter, in a Memoir, published
in Yol. VII. of the Transactions of the Royal
Society of Edinburgh. As they are now become
extremely rare, and would together form a very
small octavo volume, I cannot help thinking
that a bookseller, who should reprint them,
would be fully indemnified by the sale. The
fate of Dalgarno will be hard indeed, if, in
addition to the unjust neglect he experienced
from his contemporaries, the proofs he has left
of his philosophical talents shall be suffered to
sink into total oblivion.
Lord Stair’s Physiologia Nova Experimentalis
(published at Leyden in 1686) is also worthy of
notice in the literary history of Scotland. Al¬
though it bears few marks of the eminent ta¬
lents which distinguished the author, both as a
lawyer and as a statesman, it discovers a very
extensive acquaintance with the metaphysical
as well as with the physical doctrines, which
were chiefly in vogue at that period; more par¬
ticularly with the leading doctrines of Gassendi,
Descartes, and Malebranche. Many acute and
some important strictures are made on the
errors of all the three, and at the same time
complete j ustice is done to their merits; the
writer every where manifesting an indepen¬
dence of opinion and a spirit of free inquiry,
very uncommon among the philosophers of the
seventeenth century. The work is dedicated Notes
to the Royal Society of London, of the utility Illus®nadiong
of which institution, in promoting experimental
knowledge, he appears to have been fully
aware.
The limits of a note will not permit me to
enter into farther details concerning the state
of philosophy in Scotland, during the interval
between the union of the Crowns and that of
the Kingdoms. The circumstances of the coun¬
try were indeed peculiarly unfavourable to it.
But memorials still exist of a few individuals,
sufficient to show, that the philosophical taste,
which has so remarkably distinguished our
countrymen during the eighteenth century, was
in some measure an inheritance from their im¬
mediate predecessors. Leibnitz, I think, some¬
where mentions the number of learned Scotch¬
men by whom he was visited in the course of
their travels. To one of them (Mr Burnet of
Kemney) he has addressed a most interesting
letter, dated in 1697, on the general state of
learning and science in Europe; opening his
mind on the various topics which he introduces,
with a freedom and confidence highly honour¬
able to the attainments and character of his
correspondent. Dr Arbuthnot, who was born
about the time of the Restoration, may serve as
a fair specimen of the very liberal education
which was then to be had in some of the Scot¬
tish Universities. The large share which he is
allowed to have contributed to the Memoirs of
Martinus Scriblerus abundantly attests the va¬
riety of his learning, and the just estimate he
had formed of the philosophy of the schools ;
and in one or two passages, where he glances
at the errors of his contemporaries, an attentive
and intelligent reader will trace, amid all his
pleasantry, a metaphysical depth and soundness
which seem to belong to a later period.—Is
there no Arbuthnot now, to chastise the follies
of our craniologists ?
Note C C C, p. 214.
The letter which gives occasion to this note
was written twenty years after the publication
of the Treatise of Human Nature. As it relates,
however, to the history of Mr Hume’s studies
286
PRELIMINARY DISSERTATIONS.
Notes previous to that publication, I consider this as
iterations ^ie ProPer place for introducing it. The Dia-
logue to which the letter refers was plainly that
which appeared after Mr Hume’s death, under
the title of Dialogues on Natural Religion.
“ NineiuellS) March 19. 1751.
“ Dear Sir—You would perceive by the
sample I have given you, that I make Cleanthes
the hero of the dialogue. Whatever you can
think of to strengthen that side of the argument
will be most acceptable to me. Any propensity
you imagine I have to the other side crept in
upon me against my will; and it is not long ago
that I burned an old manuscript book, wrote
before I was twenty, which contained, page af¬
ter page, the gradual progress of my thoughts
on that head. It begun with an anxious search
after arguments to confirm the common opinion;
doubts stole in, dissipated, returned, were again
dissipated, returned again, and it was a per¬
petual struggle of a restless imagination against
inclination, perhaps against reason.
“ I have often thought that the best way of
composing a dialogue would be for two persons
that are of different opinions about any question
of importance, to write alternately the different
parts of the discourse, and reply to each other.
By this means that vulgar error would be avoid¬
ed of putting nothing but nonsense into the
mouth of the adversary; and, at the same time,
a variety of character and genius being upheld,
would make the whole look more natural and
unaffected. Had it been my good fortune to
live near you, I should have taken on me the
character of Philo in the dialogue, which you’ll
own I could have supported naturally enough;
and you would not have been averse to that of
Cleanthes. I believe, too, we could both of us
have kept our tempers very well; only you have
not reached an absolute philosophical indiffe¬
rence on these points. What danger can ever
come from ingenious reasoning and inquiry ?
The worst speculative sceptic ever I knew was
a much better man than the best superstitious
devotee and bigot. I must inform you too, that
this was the way of thinking of the ancients on
this subject. If a man made profession of phi¬
losophy, whatever his sect was, they always ex¬
pected to find more regularity in his life and Notes
manners than in those of the ignorant and illi- iuus^ations
terate. There is a remarkable passage of Ap-
pian to this purpose. That historian observes,
that, notwithstanding the established prepos¬
session in favour of learning, yet some philoso¬
phers who have been trusted with absolute
power have very much abused it; and he in¬
stances in Critias, the most violent of the
Thirty, and Aristion, who governed Athens in
the time of Sylla. But I find, upon inquiry,
that Critias was a professed Atheist, and Aris¬
tion an Epicurean, which is little or nothing
different; and yet Appian wonders at their cor¬
ruption as much as if they had been Stoics
or Platonists. A modern zealot would have
thought that corruption unavoidable.
“ I could wish that Cleanthes’s argument
could be so analysed as to be rendered quite
formal and regular. The propensity of the
mind towards it, unless that propensity were as
strong and universal as that to believe in our
senses and experience, will still, I am afraid, be
esteemed a suspicious foundation. ’Tis here I
wish for your assistance. We must endeavour
to prove that this propensity is somewhat diffe¬
rent from our inclination to find our own figures
in the clouds, our face in the moon, our passions
and sentiments even in inanimate matter. Such
an inclination may and ought to be controlled,
and can never be a legitimate ground of assent.
u The instances I have chosen for Cleanthes
are, I hope, tolerably happy; and the confusion
in which I represent the sceptic seems natural.
But, si quid novisti rectius, &c.
“You ask me, if the idea of cause and effect is
nothing hut vicinity ? (you should have said con¬
stant vicinity or regular conjunction)—I would
gladly know whence is that farther idea of causa¬
tion against which you argue ? The question is
pertinent; but I hope I have answered it. We
feel, after the constant conjunction, an easy
transition from one idea to the other, or a con¬
nection in the imagination; and, as it is usual
for us to transfer our own feelings to the ob¬
jects on which they are dependent, we attach
the internal sentiment to the external objects
If no single instances of cause and effect appear
to have any connection, but only repeated simi-
DISSERTATION FIRST.
287
Notes lar ones, you will find yourself obliged to have
and. recourse to this theory.
“ I am sorry our correspondence should lead
us into these abstract speculations. I have
thought, and read, and composed very little on
such questions of late. Morals, politics, and
literature, have employed all my time; but still
the other topics I must think more curious, im¬
portant, entertaining, and useful, than any geo¬
metry that is deeper than Euclid. If, in order
to answer the douhts started, new principles of
philosophy must be laid, are not these doubts
themselves very useful? Are they not prefer¬
able to blind and ignorant assent? I hope I
can answer my own doubts; but, if I could not,
is it to be wondered at? To give myself airs
and speak magnificently; might I not observe
that Columbus did not conquer empires and
plant colonies ?
“ If I have not unravelled the knot so well
in these last papers I sent you, as perhaps I did
in the former, it has not, I assure you, proceed¬
ed from want of good will. But some subjects
are easier than others; and sometimes one is
happier in one’s researches and inquiries than
at other times. Still I have recourse to the si
quid novisti rectius; not in order to pay you a
compliment, but from a real philosophical doubt
and curiosity.”1
An unfinished draught of the letter to which
the foregoing seems to have been the reply, has
been preserved among Sir Gilbert Elliot’s pa¬
pers. This careless fragment is in his own
handwriting, and exhibits an interesting speci¬
men of the progress made in Scotland among
the higher classes, seventy years ago, not only
in sound philosophy, but in purity of English
style.
“ Dear Sir—Inclosed I return your papers,
which, since my coming to town, I have again
read over with the greatest care. The thoughts
which this last perusal of them has suggested
I shall set down, merely in compliance with
your desire, for I pretend not to say any¬
thing new upon a question which has already
been examined so often and so accurately. I Notes
must freely own to you, that to me it appears T11 and.
J . . . rr Illustrations.
extremely doubtful, if the position which Cle-
anthes undertakes to maintain can be supported,
at least in any satisfactory manner, upon the
principles he establishes and the concessions he
makes. If it be only from effects exactly simi¬
lar that experience warrants us to infer a simi¬
lar cause, then I am afraid it must be granted,
that the works of Nature resemble not so nearly
the productions of man as to support the conclu¬
sion which Cleanthes admits can be built only on
that resemblance. The two instances he brings
to illustrate his argument are indeed ingenious
and elegant; the first, especially, which seem¬
ingly carries great weight along with it: the
other, I mean that of the Vegetating Library, as
it is of more difficult apprehension, so I think it
is not easy for the mind either to retain or to
apply it. But, if I mistake not, this strong
objection strikes equally against them both.
Cleanthes does no more than substitute two ar¬
tificial instances in the place of natural ones:
but if these bear no nearer a resemblance than
natural ones to the effects which we have expe¬
rienced to proceed from men, then nothing can
justly be inferred from them; and if this re¬
semblance be greater, then nothing farther ought
to be inferred from them. In one respect, how¬
ever, Cleanthes seems to limit his reasonings
more than is necessary even upon his own prin¬
ciples. Admitting, for once, that experience is
the only source of our knowledge, I cannot see
how it follows, that, to enable us to infer a si¬
milar cause, the effects must not only be similar,
but exactly and precisely so. Will not expe¬
rience authorise me to conclude, that a machine
or piece of mechanism was produced by human
art, unless I have happened previously to see a
machine or piece of mechanism exactly of the
same sort ? Point out, for instance, the contri¬
vance and end of a watch to a peasant, who had
never before seen any thing more curious than
the coarsest instruments of husbandry, will he
not immediately conclude, that this watch is an
effect produced by human art and design ? And
1 The original is in the possession of the Earl of Minto.
288
PRELIMINARY DISSERTATIONS.
Kotes
and
Illustrations.
I would still farther ask, does a spade or a plough contemplation of the universe, and the several Notes
much more resemble a watch than a watch does parts of it, produces upon a considering mind ? jilus5lons
an organised animal ? The result of our whole This is a question of fact; a popular question,
experience, if experience indeed he the only the discussion of which depends not upon refine-
principle, seems rather to amount to this : There ments and subtlety, but merely upon impartia-
are but two ways in which we have ever oh- lity and attention. I ask, then, what is the sen-
served the different parcels of matter to be timent which prevails in one’s mind, after hav-
thrown together ; either at random, or with de- ing considered not only the more familiar ob-
sign and purpose. By the first we have never jects that surround him, but also all the disco-
seen produced a regular complicated effect, cor- veries of Natural Philosophy and Natural His-
responding to a certain end; by the second, we tory; after having considered not only the ge-
uniformly have. If, then, the works of nature, neral economy of the universe, but also the most
and the productions of man, resemble each other minute parts of it, and the amazing adjustment
in this one general characteristic, will not even of means to ends with a precision unknown to
experience sufficiently warrant us to ascribe to human art, and in instances innumerable? Tell
both a similar though proportionable cause ? If me (to use the words of Cleanthes), does not
you answer, that abstracting from the experience the idea of a contriver flow in upon you with a
we acquire in this world, order and adjustment force like that of sensation ? Expressions how
of parts is no proof of design, my reply is, that just! (yet in the mouth of Cleanthes you must
no conclusions, drawn from the nature of so chi- allow me to doubt of their propriety.) Nor does
merical a being as man, considered abstracted this conviction only arise from the consideration
from experience, can at all be listened to. The of the inanimate parts of the creation, but still
principles of the human mind are clearly so con- more strongly from the contemplation of the fa-
trived as not to unfold themselves till the pro- culties of the understanding, the affections of
per objects and proper opportunity and occasion the heart, and the various instincts discoverable
be presented. There is no arguing upon the na- both in men and brutes; all so properly adapted
ture of man but by considering him as grown to to the circumstances and situation both of the
maturity, placed in society, and become ac- species and the individual. Yet this last obser-
quainted with surrounding objects. But if you vation, whatever may be in it, derives no force
should still farther urge, that, with regard to in- from experience. For who ever saw a mind
stances of which we have no experience, for produced ? If we are desirous to push our ex¬
aught we know, matter may contain the prin- periments still farther, and inquire, whether the
ciples of order, arrangement, and the adjust- survey of the universe has regularly and uni-
ment of final causes, I should only answer, that formly led to the belief of an intelligent cause ?
whoever can conceive this proposition to be true, Shall we not find, that, from the author of the
has exactlv the same idea of matter that I have book of Job to the preachers at Boyle’s Lecture,
of mind. I know not if I have reasoned justly the same language has been universally held ?
upon Cleanthes’s principles, nor is it indeed very No writer, who has ever treated this subject,
material. The purpose of my letter is barely to but has either applied himself to describe, in the
point out what to me appears the fair and phi- most emphatical language, the beauty and order
losophical method of proceeding in this inquiry, of the universe, or else to collect together and
That this universe is the effect of an intelligent place in the most striking light, the many in¬
designing cause, is a principle which has been stances of contrivance and design which have
most universally received in all ages and in all been discovered by observation and experiment,
nations; the proof uniformly appealed to is, the And when they have done this, they seem to
admirable order and adjustment of the works of have imagined that their task was finished, and
nature. To proceed, then, experimentally and their demonstration complete; and indeed no
philosophically, the first question in point of or- wonder,—for it seems to me, that we are scarce
der seems to be, what is the effect which the more assured of our own existence, than that.
DISSERTATION FIRST.
289
Notes this well-ordered universe is the effect of an in-
and. telligrent cause.
istrations. =•
<c This first question, then, which is indeed a
question of fact, being thus settled upon obser¬
vations which are obvious and unrefined, hut
not on that account the less satisfactory, it be¬
comes the business of the philosopher to inquire,
whether the conviction arising from these obser¬
vations be founded on the conclusions of reason,
the reports of experience, or the dictates of feel¬
ing, or possibly upon all these together; but if Notes
his principles shall not be laid so wide as to ac- m u
count for the fact already established upon prior
evidence, we may, I think, safely conclude, that
his principles are erroneous. Should a philoso¬
pher pretend to demonstrate to me, by a system
of optics, that I can only discern an object when
placed directly opposite to my eye, I should
certainly answer, your system must be defec¬
tive, for it is contradicted by matter of fact.”—
END OF THE FIRST DISSERTATION.
2
0
DISS. I. PART II.
DISSERTATION SECOND:
EXHIBITING A GENERAL VIEW
OF THE
PROGRESS OF ETHICAL PHILOSOPHY
CHIEFLY
DURING THE SEVENTEENTH AND EIGHTEENTH CENTURIES.
BY THE RIGHT HONOURABLE
SIR JAMES MACKINTOSH, LL.D, F.R.S., M.P.
A PREFACE
BY
WILLIAM WHEWELL, D.D.,
c
MASTER OF TRINITY COLLEGE, AND PROFESSOR OF MORAL PHILOSOPHY IN THE
UNIVERSITY OF CAMBRIDGE.
DISSERTATION SECOND.
ADVERTISEMENT.
In publishing a new edition of the Encyclopaedia Britannica, the Proprietors think
themselves fortunate in being able to accompany the following Dissertation with a
Preface which presents a succinct and comprehensive view of its leading objects and
doctrines. As allusion is there made to the “ irregular and interrupted manner’ in
which it was written, and to the want of any notice of the recent Ethical speculations
of the Continental Philosophers, it may be proper, injustice to the very eminent au¬
thor, to lay before the reader the following history of its composition, as given in the
interesting Memoirs of his Life, lately published by his Son.
“ The late Mr Dugald Stewart and Mr Playfair had agreed to furnish Dissertations,
the one on the history of Metaphysical, Ethical, and Political Philosophy, the other on
the history of Mathematical and Physical Science, to be prefixed to the Supplement to
the Encyclopaedia Britannica. The design was not completed by either of those illus¬
trious writers. Both died before their respective portions of it were finished. The
history of the mathematical and physical sciences, by the latter, was brought down to
the period marked by the discoveries of Newton and Leibnitz ; and the history of
metaphysical philosophy was, by the former, brought down to the close of the last cen¬
tury. In treating this great branch of his subject, Mr Stewart has occasionally ad¬
verted to the kindred branches of ethics and politics; but there was wanting to the
completion of his design a full view of the progress of opinion in those sciences, par¬
ticularly during the eighteenth century. In 1828, a new and improved edition of the
Encyclopaedia, being the seventh, was projected, and it was a part of the Editor’s plan
for the improvement of this edition, to continue the magnificent historical Disserta¬
tions that had been published with the Supplement, and to prefix the whole, in their
completed form, to this edition of the principal work. A proposal to write a Disserta¬
tion in continuation of that of Mr Stewart upon the Ethical and Political Philosophy
of the last century, was, in August 1828, accordingly made to Sir James, by the Editor,
294
PRELIMINARY DISSERTATIONS.
Mr Macvey Napier. Having already resolved to devote the remainder of his labours
to British history, he had considerable difficulty in acceding to the proposal. But his
love of the subject, his natural wish to preserve some of his early reading and reflec¬
tions, and the entreaties of Mr Napier, who had a few years before been introduced to
him by Mr Stewart, and with whom he was in the habit of corresponding, prevailed
over his scruples, and an agreement in consequence took place for the execution of an
historical Dissertation, embracing this object, and extending over the period that had
been left untouched by his predecessor. It had originally been agreed, as above stated,
that the Dissertation should include political as well as ethical philosophy, but the au¬
thor’s uncertain health, and the parliamentary duties of an interesting crisis, occasioned
the abandonment of this part of the plan, and even obliged him to omit the history of
the ethical philosophy of the Continent.
“ In a letter to Mr Napier, dated in January 1829, he says, 41 am now reconciled to
my labour by a new rising hope, that it may enable me to make some of the contribu¬
tions to Ethics which, in more ambitious days, I presumed to expect would have been
more extensive.’ And in another letter, written about the same time, he thus ex¬
presses himself: 4 You will see I have made some (I hope useful) additions to one of
the sections, and I would have made more, if I could have afforded the time. But
alas ! I have none to spare ; otherwise, I like this sort of work much better than any
other. Speaking of his progress, a little afterwards, he says, 41 begin to hope well
of my discourse, which I endeavour to make a development of ethical principles, as
they historically arose—a new attempt in our language.’
44 Again, he thus adverts to the section on Bishop Butler then just finished :—4 The
part in which I think I have done most service, is that in which I have endeavoured
to slip in a foundation under Butler’s doctrine of the supremacy of conscience, which
he left baseless.’—When he came, in April 1829, to fear that it would be necessary to
abandon all notice, not only of the progress of political philosophy, but also of the ethi¬
cal philosophy of the Continent, he expressed great regret at the probable omission of
this last section. 41 shall be quite sorry,’ he said, 4 if time should require the omission
of the continental part, which would be the newest of the whole.’
44 No one could be more thoroughly aware than himself of the imperfections that
must attach to a work on such a subject, written by snatches, and amidst such frequent
and sometimes distressing interruptions ; and he accordingly mentions that it was very
earnestly his wish 4 to leave an addition of it, with such improvements as time, criti¬
cism, conversation, and reflection might suggest.’ This very natural wish he unfortu¬
nately did not live long enough to have an opportunity afforded him of carrying into
execution.”
DISSERTATION SECOND
PREFACE BY WILLIAM WHEWELL, D.D.
A History of the Philosophy of Morals may,
for many purposes, be considered as forming a
large portion of the Philosophy itself; and pro¬
bably, to most readers, the portion which is by
far the most agreeable. The writer of such a
history, if it be worthy the name, must present
all that has been done by the moralists of pre¬
ceding times as steps in a progress; and must
thus be led to point out the ultimate position
which the subject has in his own day assumed.
The history of ethical speculations which the
following Dissertation contains, has, however, not
only the merit of exhibiting the present condi¬
tion of ethical philosophy, but has also a peculiar
advantage in the point of view from which the
subject is regarded ; since the author’s opinions
were, in the main, those to which the most mo¬
derate and popular writers of his own country
had generally been led, and which had therefore
most influenced general literature and common
reasonings. A view of Moral Philosophy written
in such a spirit, escapes, and may in some mea¬
sure correct, the exaggerations and paradoxes of
new and immature theories.
Some of Mackintosh’s views were peculiarly
his own, but much of his system of opinions was
adopted from the doctrines of the great philoso¬
phers whom he here reviews. Perhaps some
light may be thrown on the following Disserta¬
tion, by stating the main points of both kinds, as
they may be collected from the work itself; and
this will be in some measure done in the present
preface. Also, as the ethical system embraced by
Mackintosh included some tenets which have in
our own time been the subject of much contro¬
versy, and on which it appears to me that errors
have been widely prevalent, I have ventured to
make a few remarks, such as I thought most fitted
to put the doctrines in their proper point of view.
I may add, that as my author’s survey is in a
great measure restricted to British writers, I
have not thought myself called on to take note
of the direction which ethical speculations have
recently assumed in Prance and Germany, or of
the indications which have appeared in the litera¬
ture of our own country of the influence of these
foreign impulses.
The views which Mackintosh entertained, and
which were peculiarly the result of his own rea¬
sonings, are delivered in various parts of the Dis¬
sertation, but will perhaps become more intelli¬
gible by being stated as they are to be collected
296
PRELIMINARY DISSERTATIONS.
from the whole. The work was written in an
irregular and interrupted manner; a circum¬
stance which introduced many repetitions, and
a mixture of the didactic with the historical por¬
tions, which may have given rise to some con¬
fusion.
I. The first main point in Mackintosh’s view of
ethics,is his opinion, that those which aie usually
termed the benevolent affections (as, for example,
parental love and compassion) are properly de¬
scribed as disinterested. This doctrine he notices
as one of the valuable truths which Butler brought
clearly into view (p. 360); and he attaches to it
so much consequence, that, in concluding his Dis¬
sertation (p. 432), he declares himself ready to re¬
linquish his theory, if it be proved to be at vari¬
ance with the reality of the social affections, which
he there speaks of as the most indisputable and the
most important part of human nature.
Opinions opposite to this have been asserted in
various formssome, for instance, have said, that
the affections are all merely forms of self-love; or
that they are selfish ; or that they really regard
self; or have professed to deduce them from some
selfish principle, as Hobbes from the love of power.
A few remarks may here suffice on each of these
modifications of the selfish system.
(1.) Butler, and after him other writers, as well
as Mackintosh, wish, for the sake of clearness, to
confine the application of the term self-loveto that
cool and prudential regard to our own welfare
which weighs and estimates the chances and
means of happiness ; and which is thus distinct
from the passions and affections which impel us
to action immediately, without intervening reflec¬
tion or calculation of consequences. It will pro¬
bably be universally allowed, that gratitude or
pity, friendship or filial love, are clearly distinct
from self-love, in this sense. The term self-love
has been objected to altogether by some persons,
and Mackintosh himself appears to be dissatisfied
with it (p. 422). Yet it seems to be not unapt to
describe that state of mind in which we regard
ourselves as external and detached objects of soli¬
citude, and provide for our own wellbeing, as we
would do for that of a friend whose passions we
can resist, and whose future and permanent good
we try to secure, without losing our calmness
of feeling and clearness of view. The self-love
which aims at our own welfare in such a temper
may make us do kind actions ; but it is, in it¬
self, broadly distinguished from kindness and
love of other persons.
But further, it is argued by Butler and Mac¬
kintosh, that not only the benevolent affections,
but the appetites also, are clearly distinguish¬
able from this self-love. A man may, as Butler
says, eat from self-love, out of a regard to his
health ; he may also eat from the appetite of
hunger; but the grounds of action are plainly
different in the two cases. The gratification
which results from the act does not make it an
act of self-love. And just as little, they urge,
does the gratification which accompanies the ex¬
ercise of the domestic, or any other benevolent
affections, justify us in ascribing them to such
self-love as we have described.
(2.) As the object of the appetites is some¬
thing different from ourselves and our own feel¬
ings, the object of the benevolent desires is so
too. As food is the object of hunger, the grati¬
fication or the wellbeing of the child is the ob¬
ject of parental affection. The pleasure which
results when the object is attained is not the
aim of the agent, for it does not enter into his
contemplation; nor could we derive pleasure
from the attainment of such objects except the
desire had previously existed (pp. 360, 364). In
conformity with this view, it is maintained by
the writers of this school, that neither the appe¬
tites nor the desires can properly be called selfish.
{Stewart, Outlines of Moral Philosophy, p. 86.)
The term selfish, which is, I think, not used by
Butler in the part of his works now referred to,
is, however, that about which the controversy
on this subject has generally raged most hotly.
In opposition to the opinion just stated, it has
often been said, that the desire of power, of
wealth, of superiority, of esteem, are selfish prin¬
ciples.
If it be contended that these desires (and the
benevolent affections for the same reason) are
selfish because they are felt by self, Mackintosh
answers (p. 360), that acts of the understanding,
and processes of reasoning, might be called selfish
PREFACE TO THE SECOND DISSERTATION.
297
on the same ground. But it is easily seen that
something different from this is usually meant by
the assertion. When it is popularly contended
that the love of fame, for instance, is a selfish
principle of action, it is generally implied that
this affection is more selfish than to common eyes
it appears. The assertor gives himself credit for
having analysed the motive in question into ele¬
ments not immediately obvious;—for discerning
that a feeling, which at first appears to have an
elevated and exterior aim, has, in fact, latently,
a reflex view and a lower object. The dispo¬
sition which men have to be pleased with such
attempts at the dissection of motives into baser
elements, is widely prevalent: it is this dispo¬
sition, for instance, which has given to the Max¬
ims of La Rochefoucauld their charm and their
popularity.
But the flashes of the epigrammatist, what¬
ever applause they may excite, are not likely to
be of much use as a light to the philosophical
reasoner ; and the question, What motives can
properly be called selfish, as a point of moral
philosophy, must be decided in a very different
spirit. Now, the popular disposition to detect
selfishness in human motives is obviously ac¬
companied by a depreciating estimate of the feel¬
ings in which this taint is perceived. But this
disapproval, in spite of the conceit and ill-nature
in which it may originate, manifestly implies a
belief that men’s feelings may be, and ought to
be, other than selfish ; for how can we contemn
a person for having selfish feelings only, if human
nature admits of no others ? The common ap¬
plication of the term selfish, implies a moral dis¬
approbation as well as a metaphysical analysis.
We endeavour in vain to dissolve this associa¬
tion ; and yet, so long as it subsists, it is plain
that the condemnation which we pronounce in
some cases, implies the possibility of cases in
which it is not deserved. If we despise the love
of fame as a selfish motive, we reserve our ad¬
miration for motives of a different class. The
emphasis with which we apply the term, implies
that it is not universally applicable. But when
we assert, as a universal philosophical truth, that
all our affections are selfish, we employ the word
in a technical manner, distinct from its common
MSS. II.
use. Now, where is the advantage to philoso¬
phy of telling us that our love of parents and
friends, that our gratitude and compassion, are
selfish feelings, if the assertion be true only when
the word is used in a sense different from the
common one ? The paradox startles us ; when
explained, it ceases to shock ; but why incur
the necessity of such an explanation ? It must
be allowed that such affections as I have just
mentioned deserve and attract our love and
approbation as much as any feelings can do 1
why, then, use terms which seem fitted only
to direct towards them our disapproval and
aversion ?
We may add, with Brown (Lectures, vol. iv.,
p. 63), that if the benevolent and virtuous affec¬
tions are to be called selfish, it will be necessary
to form two divisions of selfish actions;—one
containing those selfish actions in which self
is the direct object; the other containing those
very different selfish actions which are usually
called disinterested. Till it is seen what advan¬
tage would be gained by this new nomenclature,
it is surely better to use terms in their usual
sense.
It is not easy to fix precise limits to the use
of the term selfish, which thus denotes, not a
positive philosophical attribute, but a compara¬
tive quality, to which some blame inevitably
clings. Mackintosh says well (p. 360), “ The
weakness of the social affections, and the'strength
of the private desires, properly constitute selfish¬
ness.” And Stewart {Outlines, p. 114) gives
nearly the same account of this word, which he
illustrates by saying, “ Though we apply the
epithet selfish to avarice, and to low and private
sensuality, we never apply it to the desire of
knowledge, or to the pursuits of virtue, which
are certainly sources of more exquisite pleasures
than riches or sensuality can bestow.”
(3.) That the benevolent affections, in their
usual form, have not self for their immediate ob¬
ject, is so evident that it needs hardly to be in¬
sisted on. In what sense can the mother who
unhesitatingly exposes her life to save that of
her child, be said to regard herself, of whom she
never once thinks 1 In what way does Desde-
mona act from self-regard, when, in the very
2 p
298
PRELIMINARY DISSERTATIONS.
article of death, she endeavours to shelter the
reputation of the husband who murders her 1
To speak of self as the object of the regard or
contemplation of the person acting in such in¬
stances, or in any instances in which the action
proceeds directly from the benevolent affections,
is to deprive words and phrases of all distinct
and intelligible meaning and use.
(4.) When any particular theory is propounded,
by which the results of the benevolent affections
are traced to some remote interested principle, a
refutation of the theory is readily suggested by a
consideration of the common characteristic cir¬
cumstances of the affections. Thus, with regard
to Hobbes’ system—that the affections have
their origin in the love of power—Butler answers
briefly, but satisfactorily, that such an hypothe¬
sis does not lead us to anything at all resembling
the known state of the case ;—that we wish
good to others quite independently of our being
ourselves the authors of it;—that we make.dis¬
tinctions among the objects of our good-will,
where the love of power would make no differ¬
ence ;—that the love of power would be gratified
by doing harm as well as good, and that thus
cruelty and benevolence would be the same affec¬
tion. (Sermon I, Note ; and the following Dis¬
sertation, p. 337.) And if it were proposed to
reduce the benevolent affections to any other
system of original principles and associations of
thought, it might be answered, that if these sup¬
posed original principles involve the desire of
any besides physical pleasures (as the desire of
wealth, power, dignity), they themselves require
analysis, at least as much as the affections. It
is at least, as possible to love a father, as it is to
desire his estate; and the greatest good that the
estate can procure us, can hardly consist of any¬
thing more intelligible than filial love. Nor
would such an hypothesis avail us ; for the affec¬
tions are, in the greater number of cases, far
stronger than any aggregation of such supposed
elements would make them. To what purpose
do we associate ideas with the desire of wealth,
power, and dignity, in order to form the family
affections, if we are compelled to allow that the
whole feeling thus produced is greater than the
sum of all its parts 1 To claim philosophical
merit for such an analysis of the disinterested
emotions into the effects of association of ideas,
is to deprive the terms Association and Analysis
of all meaning. Or how are our benevolent affec¬
tions accounted for by the need we have of our
friends as means, if this regard to the means be
both much stronger and much more distinctly in¬
telligible than the regard to the ends can ever
become ? Does not this shew that, in fact, the
hypothetical end is not our end \
On such grounds, Mackintosh and other wri¬
ters appear to do well in arranging the benevo¬
lent affections as a class of principles of action
distinct from the desire of power, superiority,
and the like. Those are not capable of being
analysed into these, and we are sensible of an
insurmountable incongruity when the two classes
are brought into comparison. If the love of a
parent be a compound of love, of power, and
similar ingredients, will it not follow, that if we
expect to gain power by sacrificing a parent rather
than by serving him, it is consistent with the na¬
ture of our best affections that we should do so ?
And is not this a conclusion too monstrous to be
accepted by any moralist ? The benevolent and
family affections, and the desire of power, appear,
then, to differ in some other way than in being
modifications of the same elements ; and, even
if we choose (unphilosophically as it has ap¬
peared) to call the latter class of principles self¬
ish, the former must be arranged in a different
group, which we cannot designate better than by
calling them disinterested.
II. The next leading principles of Mackin¬
tosh’s philosophy are, the independent existence
and the supremacy of the conscience or moral
faculty. Here also he ascribes to Butler the
merit of having first brought these doctrines into
a clear light (p. 361); though Hutcheson, who
1 Desdemona. A guiltless death I die.
Emilie. 0 who hath done
This deed ?
JDesderriona. Nobody ; I myself; farewell;
Commend me to my kind lord; 0 farewell—(Dies.')
PREFACE TO THE SECOND DISSERTATION.
299
had somewhat of a steadier view of this faculty,
gave it the name of the moral sense.
The question of the moral sense has been much
discussed since Butler’s time. It is not neces¬
sary here to go fully into this controversy, but I
may be allowed to make a few remarks on some
of the arguments connected with the following
Dissertation.
(1.) In the first place, as to the existence of
the moral faculty. It is allowed on all sides that
we have a conception of moral obligation ; and
the question is, Whether this conception can be
resolved into some operation of the intellectual
faculties, as the perception of general utility ; or
whether, on the contrary, it is incapable of being
thus resolved, and must properly be ascribed to
a separate faculty.
It will readilyappear that the discussion of this
question must be attended by great difficulties,
for we cannot easily find a test to determine, or
terms to express, the identity or the difference of
our perceptions of the useful and the right. These
internal perceptions can only be described by
means of analogical and metaphorical language ;
and this must discharge its office very imperfectly •
Even with respect to external senses, where the
meaning of our terms is naturally much more
clear and palpable, an exact treatment of such
questions is far from easy. We cannot, by mere
language, convey a conception of the difference
of sights and sounds. Is the perception of form
a different faculty from the perception of colour 1
This question has been found extremely perplex¬
ing ; we may therefore be certain that the ques¬
tion of the distinct existence of the moral faculty
will require great clearness and steadiness of
thought for its solution.
But still the question does not seem to be in¬
capable of answer. Do we mean the same thing
when we say that an action is right, and when
we say that it is, on the whole, and taken in all its
consequences, useful 1 It must be observed, that
the question is not, Whether right actions are,
on the whole, useful; for that we will suppose to
be granted; but it is, Whether, by describing
them as right, we mean nothing more than that
we believe them to be useful ? If by right, and
by equivalent words, we intend some quality
and attribute which useful and similar terms do
not express, we must have the faculty of con¬
ceiving such a quality; and this faculty is the
moral sense. Such a faculty Butler, and after him
many modern writers, including Mackintosh, hold
to be part of human nature. The following are
some of the grounds for his opinion :
(2.) The words which express what is morally
right, and the related ideas, cannot be replaced
by any different set of terms. Bight, duty, what
we ought to do, are not expressed to the satis¬
faction of any one by any phraseology borrowed
from the consideration of consequences. They
are as untranslatable into the language which
contemplates utility alone, as the names of co¬
lours are incapable of being expressed by those
denoting the properties of space. When I say
that an act is my duty, that it is right, I give an
entire assent to the rule which commands me to
do it, whatever be the consequences.1 It may
be true that all acts of duty are, taken in all
their consequences, useful; but assuredly this is
not what we mean, this is not the quality we
ascribe to them, by the use of such terms.
Perhaps the most distinctive of these terms is
the word ought, and the corresponding words
which occur in all languages. It is universally
felt that when we say, in a moral sense, that we
ought to do any action, we mean something dif¬
ferent from saying it is advantageous in its con¬
sequences. This word ought, which, as Mackin¬
tosh says “ most perfectly denotes duty,” appears
to be the simplest and most universal expression
of the moral sense.
(3.) The impossibility of wresting this word,
ought, to the side of the utilitarian theory, may,
I think, be inferred from the amusing vehe¬
mence with which Mr Bentham endeavours to
expel it from his territory. “ The talisman of
arrogance, indolence, and ignorance, is to be
found in a single word, an authoritative impos¬
ture, which in these pages it will be frequently
necessary to unveil. It is the word ‘ ought,’
4 ought or ought not,’ as circumstances may be.
1 Whewell’s Elements of Morality, Art. 73. (2d Edition.)
300
PRELIMINARY DISSERTATIONS.
In deciding you ought to do this, you ought not
to do it, is not every question of morals set at
rest ?
“ If the use of the word be admissible at all,
it ‘ought’ to be banished from the vocabulary of
morals.” (Deontology, vol. i., p. 32.)1
Till this is done, he proposes to neutralise this
obnoxious term by the use of another potent
word—‘whyT
It is clear that the reason why the word so
frequently occurs to excite Mr Bentham’s dis¬
pleasure is, that it refers to a universal and un¬
avoidable aspect of actions, which men constant¬
ly recognise, and cannot help expressing in the
words they familiarly employ. And Mr Ben¬
tham’s “why” involves an assumption no less
dogmatical than that of which he complains; for
by it he intends to prescribe that the answer
shall be in no other language than that of the
utilitarian theory.
(4.) The unavoidable occurrence of the con¬
ception implied in the word ought, notwith¬
standing that it resists the attempt at analysis
of which we have just spoken, may be inferred
from its use by those whose theoretical views
would lead them to reject it; as, for example,
Mr Bentham himself. He supposes a contro¬
versy between an ancient and a modern moral¬
ist. (Deont., vol. i., p. 72.) “ The modern, as
probably he will keep neither his principles nor
his temper, says to the ancient, ‘ Your moral
sense is nothing to the purpose; yours is cor¬
rupt, abominable, detestable; all nations cry out
against you.’ ‘ No such thing,’ replies the an¬
cient ; ‘ and if they did, it would be nothing to
the purpose : our business was to inquire, not
what people think, but what they ought to
think.'" And this “ought” of the ancients is
supposed to terminate the controversy, so far as
dialogue is concerned.2
(5.) It is, indeed, expressly allowed by Mr
Bentham himself, that the word utility, and its
conjugates, do not express our judgment in cases
of moral conduct. “ The mind Avill not be satis¬
fied,” he says (vol. i., p. 35), “ with such phrases
as—‘it is useless to commit murder,’ or ‘it
would be useful to prevent it.”’ Surely we
may be allowed to say that the reason why men
are not satisfied with such phrases is, that they
do not express their meaning. The repugnance
and indignation with which we regard crimes
and vices is something distinct from the percep¬
tion of their results ; and no word which expres¬
ses the transgression of utility satisfies us, except
it also express the transgression of rectitude.
Murder is harmful to society, but it is also
wicked. The former expression states the view
of our understanding as to the consequences of
the act; the latter expression conveys the feel¬
ing of our moral nature as to its moral quality:
the utilitarian scheme of Mr Bentham appears
to aim at confounding these assertions.
(6.) But the same recognition of the difference
of duty and usefulness in common apprehension,
which Mr Bentham has made in the passage just
quoted, appears also in other circumstances ; as,
for instance, in the title of the work already quoted,
Deontology, and in the reasons assigned for coin¬
ing such a name. This term is professedly chosen
because “ utilitarianism offers too vague and un¬
defined an impression to the mind.” (Vol. i., p.
34.) If the word from which Deontology is de¬
rived had borrowed its meaning from the notion
of utility alone, it is not likely that it would have
become more intelligible by being translated out
of Latin into Greek. But the term Deontology
expresses Moral Science (and expresses it well),
precisely because it signifies the Science of Duty,
and contains no reference to utility. It is a term
well chosen, to describe a system of ethics founded
on any other than Mr Bentham’s principle. Mac¬
kintosh, who held that ro d'eov,—what men ought
to do,—was the fundamental notion of morality,
might very properly have termed the science
Deontology. The system of which Mr Bentham
is the representative—that of those who make
1 The title of this hook is “Deontology, &c., from the MSS. of Jeremy Bentham;” but recently I have been blamed in a
Review for citing it as his. (1852.)
2 Perhaps the reader may be amused by Mr Bentham’s mode of winding up the scene :—“Thereupon the modern kicks
the ancient, or spits in his face ; or, if he is strong enough, throws him behind the fire. One can think of] no other method
that is at once natural and consistent, of continuing the debate.” It is satisfactory to see that Mr Bentham does not seem
to have thought the use of the word ought by the one party, though very provoking, justified the extreme measures which
he describes on the other side.
PREFACE TO THE SECOND DISSERTATION.
301
morality dependent on the production of happi¬
ness, has long been designated in Germany by the
term Eudemonism, derived from the Greek word
for happiness (ivbcufiovia). If we were to adopt this
term we should have to oppose the Deontological
to the Eudemonist school; and we must necessa¬
rily place those who hold a peculiar moral faculty,
—Butler, Stewart, Brown, Mackintosh,—in the
former, and those who are usually called utilita¬
rian philosophers in the latter class.
(7.) The irrelevancy of Paley’s mode of treating
the question of the moral sense is so generally al¬
lowed at present that we need not dwell on it here.
But we may observe, that other mistakes, flowing
from a like misapprehension, effect his analysis of
virtue. He endeavours to make an advance in
this inquiry by the question, “Why am I obliged
to keep my word, or to do any other moral act V'
And by his answer to this question, he reduces
moral obligation to two elements—external con¬
straint, and the command of a superior. This
attempt at an analysis of morality is singularly
futile : for, of the two supposed elements, external
constraint annihilates the morality of the act, and
the reference to a superior presupposes moral ob¬
ligation, since a superior is one whom it is our
duty to obey. If Paley had stated his question
in the simpler form, “ Why ought I to keep my
word ?” he would have had before him a problem
more to the purpose of moral philosophy, and one
to which his answer would have been palpably
inapplicable.
(8.) The argument hitherto urged has been,
that the impossibility of resolving the ideas of
moral right and duty into other ideas, borrowed
from utility, is implied in the common use of
language ; and virtually acknowledged by utili¬
tarian writers themselves. Other arguments may
be drawn from the nature of the feelings with
which we contemplate actions, and which, it has
been truly said, are quite irreconcileable with the
supposition that our moral estimate of actions
arises from their bearing on happiness, and that
our moral estimate of men looks only to their
having calculated such consequences well or ill.
Our admiration of the higher virtues, our indig¬
nation and scorn of the baser vices, are entirely
different from an assent to, or dissent from,
the agent’s estimate of consequences. We can
conceive a remorse for sins committed, which is
something very distinct from a regret at having
mistaken the road to happiness. A bad man, in
a moral sense, is not merely a man who has had
a bad head for calculating consequences, as he
would be if morality resided in the intellect alone.
But this argument has been sufficiently insisted
upon by others.
(9.) Thus, as we separate the affections from
the desires, we distinguish the moral sense, or
conscience, from both. Butler, and Mackintosh
with him, express the relation of conscience to
the other principles of action, by ascribing to it
a supremacy,1 or a right of command. This lan¬
guage is metaphorical, but in that respect it does
not differ from all the rest of the language which
we use concerning mental operations and rela¬
tions ; and the material question is, whether, in
this case, the language is intelligible. It is lan¬
guage which has been familiarly used from the
time of Aristotle and Plato to our own ; and I
think it will be seen by any one who reads with
attention the pages of good writers who employ
this language, as for instance Butler, that they
have a distinct meaning in their minds, and that
their expressions are fitted to convey it. Butler
shews that prudential self-love is a principle dif¬
fering from the desires and passions in other ways
than in mere strength ; and thus establishes that
there is a difference of kind and order, as well as
of degree and power, among our active principles.
He reminds us that we can conform our acts to
rules, and that this differs from acting as we
please, or obeying the strongest impulse ; that
man is intelligibly said to contain in his own mind
a law of right action ; that under the influence of
such a principle he approves and condemns, and
thus passes judgment on acts and dispositions ;
that this is the proper office of such a principle ;
1 The use of the term Supremacy, as ascribed to the conscience, is liable to convey an erroneous and dangerous doctrine,
that every one’s conscience is for him the supreme rule of right and wrong. The word Authority, which is all that Butler
and Mackintosh’s argument requires, avoids this inconvenience.
See the Preface to Whewell’s edition of Butler’s Three Sermons on Human Nature, and Whewell’s Elements of Morality,
art. 271, 2d edit. (Note added 1852.)
302
PRELIMINARY DISSERTATIONS.
and that right and authority are implied in this
office. When we have distinguished the moral
sense from the other faculties of our nature, such
language appears to convey, as well as language
can convey, the relation of that faculty to the
others. “ To declare what ought and ought not
to be done,” it has been said, “ is the essence of
command, that is, of moral command or rightful
authority.” And thus such authority belongs to
the faculty which determines that some of our
actions and emotions are, and others are not, what
they ought to be.
We shall have to speak farther of this supre¬
macy of conscience in treating of Mackintosh’s
explanation of it. But we may, in the first place,
say a few words on the application of this doc¬
trine to questions of ethics.
(10.) Mackintosh has, with great propriety,
insisted upon the importance of a distinction of
two parts of Moral Philosophy, which are often
confounded ;—the Theory of Moral Sentiments,
and the Criterion of Morality, (p. 313.) The
question of the independent existence and cha¬
racter of the moral faculty belongs to the former
division of the subject; the construction of our
system of ethics flows from the latter. There is
no necessary collision between doctrines on these
two points. We may hold that morality is an
original quality of actions, and may still form our
rules of morality by tracing the consequences of
actions.
This distinction has often been neglected.
Those who hold that utility constitutes morality,
often call upon the advocates of a moral sense, to
shew how the assertion of such a faculty leads us
to distinguish right from wrong, or how it can su¬
persede the criterion of general utility. To this
it may be replied ;—that the existence of a moral
conscience in man is an important truth, but that
this truth alone cannot be expected to replace all
the principles and deductions by which a sound
system of philosophical ethics is to be produced ;
that the construction of such a system is un¬
doubtedly a difficult problem ;—but that we shall
inevitably obtain an erroneous solution of the
problem, if we do not take into our account the
operation of the moral faculty. The criterion of
utility cannot safely be applied without acknow¬
ledging the independent value of morality, any
more than the moral faculty can always decide
well without the consideration of consequences.
For among the most important results of actions,
we must include their effect upon the moral
habits and feelings of men; and must consider
these effects as claiming attention for their own
sake. The promotion of human virtue must be
our aim, as well as the augmentation of human
happiness. We cannot by any analysis exclude
the former of these ends ; happiness depends on
the exercise of the virtuous affections, far more
clearly than virtue depends on the pursuit of
happiness. The most wise and moderate of the
utilitarian moralists do, accordingly, apply their
method in this manner. Thus Paley, (B. III., p.
ill., C. ill.) in estimating the guilt of corrupting
a person to the commission of one offence, states
it as one ground of condemnation, that such se¬
duction is the destruction of the person’s moral
principle. And it appears, at present, to be ge¬
nerally allowed, that the utilitarian doctrine can¬
not be applied without considering the effect on
the moral feelings of men as among the important
consequences of action. “ It often happens,” it
is said, “ that an essential part of the morality or
immorality of an action, or a rule of action, con¬
sists in its influence on the agent’s own mind.”
“Manyactions moreover, produce effects on the
characters of other persons besides the agent.”
The effects here spoken of are, in fact, effects on
the moral habits of thought; and thus the ex¬
istence of the moral attributes of the mind, as
original and independent objects of the attention
of the ethical philosopher, is presupposed in this
mode of applying the utilitarian scheme.
If, indeed, we take such good and bad conse¬
quences into the account;—if among the useful
effects of actions, we conceive the most useful to
be the improvement of man’s moral character ;—
if we frame our rules so that they shall conduce
as much as possible to virtuous feeling, as well
as to beneficial action,—to purity of heart, as
well as to rectitude of conduct;—if we aim at
man’s general well-being, and not merely at his
gratification ;—I know not what moralist would
object to a criterion of morality so drawn tram
consequences, or would deny that the promotion
of human happiness, and of human virtue, require
the same practical rules. Mackintosh would un-
PREFACE TO THE SECOND DISSERTATION.
BOB
doubtedly have assented to this ; for he not only
allows the universal coincidence of virtue with
utility in the largest sense (p. 417), hut founds
his recommendation of the highest forms of vir¬
tue on the advantage of virtuous habits and feel¬
ings, both to the possessor and to the community;
as when he speaks of the trite example of Regu-
lus (p. 355), of the character of Andrew Fletcher
(p. 399), and of the virtue of courage (p. 397).
If we could take into due account the whole
value of right principles, and the whole happiness
produced by virtuous feelings, we could commit no
practical error in making the advantageous conse¬
quences of actions the measure of their morality.
But this can happen only by considering mo¬
ral good as a primary object, valuable for its own
sake; not by supposing that virtue is aimed at,
as subservient to some other purpose of more
genuine utility: and no sagacity or fairness in
estimating useful consequences can stand as a
substitute for the love of right itself. It is true,
that honesty is the best policy; but he who is
honest only out of policy, does not come up even
to the vulgar notion of a virtuous man. If a
man were tempted by the opportunity of gaining
a large estate through a safe but fraudulent pro¬
ceeding, the utilitarian doctrine would seem to
recommend him to Aveigh both sides well, though
it would direct him in conclusion to decide in fa¬
vour of probity; but the common judgment of
mankind would hardly deem him honest if he
hesitated at all. And in like manner in regard
to other temptations, the safety of virtue appears
to consist so little in tracing all possible conse¬
quences, that it has been held, that to deliberate
is to be lost, and that the only secure protection
is that purity of mind which will not look at the
prospect of sensual pleasure when it forms one
side of the account. We cannot help saying
with Cicero, “ Ilaec nonne est turpe dubitare
philosophos, quse ne rustici quidem dubitent \ ”
{Off. m. 19.)
Indeed, it appears to be acknowledged by the
advocates of the rule of utility, that it is not safe
to apply the principle separately in each parti¬
cular case. Mr Bentham has urged with great
beauty of expression {Deontology, vol. ii., ch. i.),
the propriety of framing general rules, and con¬
forming our practice invariably to these, so as to
avoid the temptations of our frailty and passion
in particular instances. If a reverence for gene¬
ral maxims of morality, and a constant reference
to the common precepts of virtue, take the place,
in the utilitarian’s mind, of the direct applica¬
tion of his principle, there will remain little dif¬
ference between him and the believer in original
moral distinctions ; for the practical rules of the
two will rarely differ, and in both systems the
rules will be the moral guides of thought and
conduct.
(11.) But though the two schools agree so far,
there still will be found a deficiency on the part
of the consistent utilitarian. A persuasion that
moral good is something different from, and su¬
perior to, mere pleasure, is requisite to give our
preference of it that tone of enthusiasm and af¬
fection which belongs to virtuous feeling. To
approve a rule as right, is different from liking
it as profitable; to admire an act of virtuous
self-devotion as we are capable of admiring, is a
feeling so different from the apprehension of any
usefulness the act may have, that the comparison
of the two things is altogether incongruous. The
moral faculty converts our perception of the qua¬
lity of actions into an affection of the strongest
ki id; nor can we be satisfied with any account
of our moral sentiments which excludes this fea¬
ture in the process. Thus, as we hold the affec¬
tions to be motives of an order superior to the
desires which have reference to ourselves only,
we maintain the moral faculty, the conscience,
the affection towards duty, to be a principle of
action of an order superior both to the desires
and to the other affections. Without the ac¬
knowledgement of this subordination, the lan¬
guage and feelings of men when they compare
the claims of personal pleasure, of social affec¬
tion, and of duty, are altogether unintelligible
and absurd.
(12.) Of those who have held the doctrine op¬
posite of this, namely, that all these sentiments
are composed of elements the same in kind,
Paley has expressed the opinion in perhaps
the most offensive form, being carried on part¬
ly by his love of clearness, and partly by his
indifference to mere speculation. “ In this in¬
quiry,” he says, “ I will omit much declama¬
tion on the dignity and capacity of our nature,
304
PRELIMINARY DISSERTATIONS.
the superiority of the soul to the body, the ra¬
tional to the animal part of our constitution :
upon the worthiness, refinement, and delicacy of
some satisfactions, and the meanness, grossness,
and sensuality of others ; because I hold that
pleasures differ in nothing hut in continuance
and in intensity”
If we could use such a term without an unbe¬
coming disrespect towards a virtuous and useful
writer, this opinion might properly be called bru¬
tish, since it recognises no difference between the
pleasures of man and those of the lowest animals.
If we are to promote human happiness in this
sense, I do not see how the same obligation does
not lie upon us to promote the happiness of brutes
with the same care. And if the pleasures of sense
differ only in intensity and duration from the
pleasures of filial and parental affection, we ought
to know how many days of luxurious living are
equivalent to the pleasure of saving a father’s life,
that we may decide rightly when these claims hap¬
pen to come in competition. If utilitarian moral
obligation consists in being regulated by such cal¬
culations, we cannot be surprised at the disgust
with which so many persons speak of the scheme
which refers us to “ the calculations of utility.”
(13.) I shall not pretend to determine whe¬
ther Mr Bentham, and those who agree with him,
have sometimes overlooked the conditions under
which alone their principle can be safely applied;
or whether, at any period, they were justly liable
to Mackintosh’s censure (p. 392) of “ clinging to
opinions because they are obnoxious; of wantonly
wounding the most respectable feelings of man¬
kind.” In more recent times this cannot, I think,
be said of them ; for extreme opinions on the poli¬
tical questions of the day, however unfavourable
may be their influence on the moral speculations
with which they are combined, are not appro¬
priately spoken of in such terms. At present I
think we may discern in utilitarian writers a wish
to conciliate rather than to shock the moral sym¬
pathies of their countrymen ; and perhaps the
opposite schools of moralists may thus be brought
nearer to each other. If those who profess to
make the utility of our actions the measure of
their morality, include in utility the effect upon
the moral habits of ourselves and others;—if they
repel with indignation the charge that they lose
sight of virtuous feeling, and of the beneficial in¬
fluence of good actions on the frame of mind ;—
if they claim to have their estimate of good inter¬
preted in the same way as Plato’s ; and speak of
“ that generous and inspiring tone which gives so
much of their usefulness as well as of their charm”
to writings such as his;—if they even become dis¬
contented with the name of utility, and wish to
have their science called deontology ;—the ques¬
tion at issue between them and their opponents
ceases to be a difference of moral rule, and, almost,
to be a discordance of moral feeling; and becomes
rather a point of metaphysical analysis. They
do not indeed become a deontological school, but
they shew how near a eudemonist school may
approach to being so.
Whether such an approximation would gratify
the writers to whom I refer, I have no means of
knowing; and if I am told that I am mistaken
in my interpretation of the indications to which
I have alluded, I shall not attempt to maintain
the opinion. It would be nothing new or strange
if persons honestly seeking truth from different
quarters, should be led towards the same point;
but if they bring with them an angry and hostile
spirit, they may approach only to quarrel more
bitterly. It is, however, possible to seek truth
of all kinds in a calm and charitable temper ; and
it would be very strange if moral truths were
held to be an exception to the desirableness of
doing this. Captiousness and petulance, fierce¬
ness and menace, personal contumely and angry
buffoonery, may be used in this as in other dis¬
cussions ; but I conceive that no writer on morals,
duly feeling the dignity and obligations of his
office, will, by any act of his, recognise those who
have recourse to such modes of treating the sub¬
ject, as moral philosophers.1
III. I now proceed to notice a third principle
which enters into Mackintosh’s philosophy, and
1 Perhaps we have now reached a period, when I may remark, without reviving any angry feelings, that these expressions
were intended to refer to Criticisms of this Dissertation of Mackintosh which had been published, and especially to a Frag¬
ment on Mackintosh, the title of which was, I suppose, suggested by Bentham’s Fragment on Government, the latter being a
severe criticism on a portion of Blackstone’s Commentaries. (Note added 1852.)
PREFACE TO THE SECOND DISSERTATION.
305
which, in the way in which he holds it, is more
peculiar to him than the two hitherto stated.
He assents, in a great measure, to the explana¬
tion suggested by Hume and Smith (p. 376), but
more fully developed by Hartley (p. 382), of the
formation of our passions and affections, and even
of our sentiments of virtue and duty, by means
of “ the association of ideas.” He further urges
this theory more at length in his general remarks
(p. 421).
(1.) But into this view, as usually understood,
he introduces several modifications ; and, in par¬
ticular, he asserts that the effect of such “ asso¬
ciation” may be something very different from the
mere juxtaposition of the component elements.
Thus he says that the result may be so entirely a
single sentiment, that “ the originally separate
feelings can no longer be disjoined” (p. 384);
and, moreover, that 1 11 the compound may have
properties not to be found in any of its compon¬
ent parts as constantly happens, he observes,
in material compounds.
It is clear that this view of the effect of the “as¬
sociation of ideas,” may give results very differ¬
ent from those often founded upon that doctrine.
If we say that gratitude, or compassion, or pa¬
triotism, are only certain trains of pleasurable
associations, we are generally understood to assert
that we can again resolve those feelings into the
constituent and associated elements ; and that by
so doing we may hope to reason upon them most
philosophically and exactly. But Mackintosh’s
mode of considering these and other emotions
would allow of neither of these inferences. He
supposes “ association” to be employed in the edu¬
cation rather than in the creation of our moral
sentiments ; in awakening affections rather than
in connecting notions.
(2.) The ideas or the feelings which are con¬
cerned in this process, are said to be associated ;
but this is, he declares, a very inadequate word to
express the “ complete combination and fusion”
which occur (p. 381). This association presup¬
poses laws and powers of the mind itself, accord¬
ing to which the conjunction produces its results.
The celebrated comparison of the mind to a sheet
of white paper is not just, except we consider
that there may be in the paper itself many cir¬
cumstances which affect the nature of the writing
(p. 380). A recent writer, however, appears to
me to have supplied us with a much more apt
and beautiful comparison. Man’s soul at first,
says Professor Sedgwick, is one unvaried blank,
till it has received the impressions of external
experience. “ Yet has this blank,” he adds,
“ been already touched by a celestial hand ; and,
when plunged in the colours which surround it,
it takes not its tinge from accident but design,
and comes out covered with a glorious pattern.”
—{Discourse on the Studies of the University,
p. 54.) This modern image of the mind as a
prepared blank, is well adapted to occupy a per¬
manent place in opposition to the ancient sheet
of white paper.
(3.) Not only the word association, but also
the word ideas, in the Lockian expression, ap¬
pears to Mackintosh to be unsuited to its pur¬
pose : since an association takes place “ of
thoughts with emotions, as well as with each
other” (p. 382). Our author has indeed shewn
great solicitude to bring into clear view that part
of our nature which he here distinguishes from
thought;—“ that other part of it, hitherto with¬
out any adequate name, which feels, and desires,
and loves, and hopes, and wills” (p. 336). After
balancing the various terms which may be used
to express the aggregate of such feelings, he in¬
clines finally to call it the emotive ox pathematicx
part of man (p. 380).
Thus the “ association of ideas,” according to
Mackintosh, would more properly be termed the
composition of ideas and emotions. In his view
of the composite, as losing all trace of apparent
composition, the author was, in some measure,
following Hartley (p. 385), though he justly
claims the credit (p. 384) of seeing more distinctly
than his predecessors the important truth, that
the compound may have properties not found in
any of its component parts.
(4.) Mackintosh maintains that this is by no
means a modification of the selfish system (p.
407) ; for the “ affections and the moral senti-
1 These terms have not had much “ luck” (to use Mackintosh’s own phraseology in this passage). In common language, this
part of our nature is often called the heart, as distinguished from the head. We may perhaps best describe it by the compound
phrase used in the Dissertation itself; the desires and affections. Some recent writers have spoken of the emotional part of
our nature. (1852.)
DlSS. II. 2 Q,
306
PRELIMINARY DISSERTATIONS.
ments, though educed by association, only be¬
come what they are when they lose all trace of
self-regard.” “ If the affections be acquired,
they are justly called natural; and if their origin
be personal, their nature may and does become
disinterested."
IV. But we must now consider another pecu¬
liarity of Mackintosh’s system ; I speak of what
he names his Theory of Conscience.
(1.) Being persuaded, as we have seen, that
the moral faculty exists and exercises a rightful
supremacy over the active principles, he has at¬
tempted to explain and account for this relation
of our emotions. His view is given in his re¬
marks on Butler (p. 362), and again in his con¬
cluding remarks (p. 425). According to this
theory, the moral faculty consists of a class of de¬
sires and affections which have dispositions and
volitions for their sole object. This description
of our moral sentiments will, he conceives, ex¬
plain their peculiar character and attributes. He
expresses the relation which he wishes to describe,
by saying that the moral sentiments are in con¬
tact with the will (p. 362); or, as he further elu¬
cidates this, “ they may and do stand between
any other practical principle and its object, while
it is absolutely impossible that any other shall
intercept their connection with the will.” The
conscience requires virtuous acts and dispositions
to action; and by such requisition it can check
and control any desires of external objects; but
no desire of any outward gratification can pi event
the conscience from demanding a virtuous direc¬
tion of the will; and this mental relation explains
and justifies, Mackintosh conceives, that attribu¬
tion of supremacy and command to the conscience
on which moral writers have often insisted (p.
362).
(2.) Thus conscience consists in, or rather re¬
sults from, the composition of all those senti¬
ments, of which the final object is a state of the
will, intimately and inseparably blended, and
held in a perfect state of solution (p. 424); and
the conscience being thus represented as analo¬
gous to the desires, it implies, in the same way
as other desires, a sense of what is grateful, and
a faculty of dwelling, in thought, on the gratifica¬
tion so obtained.
(3.) But if, in order further to develop this
theory, it be asked what states of the will are thus
agreeable to the conscience; or, in other words,
what, according to this system, is the general
character of the dispositions and actions which
we consider good and right; Mackintosh’s an¬
swer would be, that the conscience, being edu¬
cated and awakened by certain processes of asso¬
ciation, is thus composed of various elements, and
finds good under various forms ;—that (p. 423)
the beneficial volitions are delightful, and that,
therefore, they strongly attract those affections
which regard the will, and thus give rise to some
of the elements of conscience ;—that our anger
against those who disappoint our wish for the
happiness of others, when in like manner de¬
tached from persons and transferred to disposi¬
tions, becomes a sense of justice, another element
of conscience ;—that courage, energy, decision,
when tamed by the society of the affections, and
considered as dispositions only, become magna¬
nimity, and gratify the moral sense ;—and that
even those habits which mainly affect our own
good, as temperance, prudence, when they be¬
come disposition and not calculation, are for like
reasons, added to the constituents of conscience
(p. 424).
(4.) Thus the view of the nature of conscience
here presented, explains how it is that the private
desires and the social affections alike fall under
the authority of the moral faculty. The expla¬
nation of this community of rule in sentiments
of so widely different nature, Mackintosh con¬
siders a strong confirmation of the justice of his
opinion (p. 425).
Without pronouncing a judgment on the truth
of this theory, I hope I have faithfully represent¬
ed the author’s meaning. But he draws from
the theory certain inferences, of which I may say
a few words.
V. Mackintosh, as we have seen, maintains
that though the moral faculty is formed or educed
by intercourse with the external world, it is a
law of our nature; yet he allows that what this
law prescribes, agrees with the rule, rightly un¬
derstood, of bringing forth the greatest happiness.
He was, therefore, naturally called upon to ac¬
count for this coincidence. If moral approval be
PREFACE TO THE SECOND DISSERTATION.
307
a different sentiment from the estimation of gene¬
ral happiness, why does the moral sense of man
invariably approve that which increases the
happiness of his species'? If this theory ac¬
count for this phenomenon, such a circumstance
will, he conceives, be a strong argument in its fa¬
vour.
(1.) He replies to this inquiry (p. 426), that
all the separate objects which conscience ap¬
proves, the social affections, the decisions of jus¬
tice, the maxims of enlightened prudence, tend
to the happiness of some part of the species, and
and that thus the general rules of conscience must
agree with the rules of the general happiness.
All the acts which the moral faculty sanctions
promote the welfare of some part of mankind,
and all that reason has to do is to add up the items
of the account. All the principles of which con¬
science is composed, converge towards the hap¬
piness of man ; and therefore this may be taken
as its central point. And thus the coincidence
just noticed is not accidental, but is a necessary
consequence of the theory.
(2.) I will add, as a corollary to what Mackin¬
tosh has said, that a system of ethics, rightly con¬
structed on the principle of promoting, in the
greatest degree, the happiness of mankind, will
coincide, in most of its rules of action, with a
system founded on the supreme authority of con¬
science ; but that, in order to apply safely and
well the eudemonist principle, we must recollect
that happiness consists rather in habits of the
mind than in outward gratifications ; and is to be
sought rather by forming moral dispositions than
by prescribing acts. In Paley’s “ Moral Philo¬
sophy,” we have a work framed on the endemo-
nist basis, which has for some time possessed
considerable authority in this country, and has
probably in no small degree influenced men’s rea¬
sonings on such subjects in recent times. With¬
out examining here how far Paley has always
applied his principle under due conditions, and
traced his consequences with a sufficiently en¬
larged survey, we may observe that there prevails
through the work a tone of practical sagacity,
good sense, and good feeling, which neutralizes
most of its theoretical defects.
VI. Some other bearings of Mackintosh’s theo¬
ry may be noticed, and especially the view it of¬
fers of the relation of religion and morality. This
agrees nearly with the doctrine of Butler, and
many English divines, that conscience is one of
the ways in which the commands of God are con¬
veyed to us (p. 427). “ The completeness and
rigour acquired by conscience when all its dic¬
tates are revered as the commands of a perfectly
good and wise Being, are so obvious, that they
cannot be questioned by any reasonable man,
however wide his incredulity may be. It is thus
that conscience can add the warmth of an affec¬
tion to the inflexibility of principle and habit.”
Not only are we bound to accept all the precepts
for the moral government of the will, disclosed
either by Revelation or by reason, as undeniable
rules for our feelings and actions ; but the rela¬
tions between man and his Maker, which reli¬
gion teaches us, tend to make this a work of love,
no less than of duty; and bestow on that im¬
provement of our inward nature to which con¬
science is constantly urging us, an aspect of hope
and joy, which human morality, without such aid,
can hardly assume, and seldom long retain.
VII. I will only refer to one other consequence
of this theory of conscience of Mackintosh;—the
view it appears to him to supply of the celebrated
question of Pree-will (p. 430). Since conscience
contemplates those dispositions only which de¬
pend on the will, it excludes all consideration of
the cause in which the will originated : hence
the voluntary dispositions appear as the first link
of the chain; and, in the eye of conscience, will
is the independent cause of action. Reason, on
the other hand, must consider occurrences as
bound together by the connection of cause and ef¬
fect, and thus sees only the strength of the neces¬
sitarian system. Thus, while speculation appears
to shew that our actions are necessary, practice
convinces us that they are free. The advocates of
necessity and of free-will look at the question from
different points of view;—that of the understand¬
ing and that of the conscience. But the conscien¬
tious view being strengthened by the moral sym¬
pathy of mankind, is by far the most generally
and strongly entertained.
I shall here close my remarks on the Disserta¬
tion which the followmgpages contain. The theo-
308
PRELIMINARY DISSERTATIONS.
retical view of the nature, formation, and opera¬
tion of our moral sentiments, which is given by
the author, must be left to the consideration of
those who pursue such speculations in a philoso¬
phical spirit and temper. His historical sketch
of the progress of the subject has in it much to
please and instruct, to interest and improve the
ethical student. There will be found several in¬
stances in which the phraseology is defective in
clearness and simplicity; and in this, as in any
work, if we pay no attention to the writer’s aim,
if we insist upon confounding what he has dis¬
tinguished, and upon interpreting his language
by an analysis which he did not acknowledge, we
shall not obtain his sense, or any sense. But the
reader who candidly seeks for the author’s mean¬
ing will, I think, not fail to find it: and I am per¬
suaded that most readers will derive pleasure from
the comprehensive views, the tolerant temper,
and the love of virtuous feeling and literary beau¬
ty which they will find pervading the work. His
unfavourable judgments, in those cases in which
he expresses such, are less severe than those of
other philosophers, both in our own and in other
countries, who look at the progress of moral phi¬
losophy from a like point of view; and he always
appears to rejoice to give credit to any writers in
whom he discovers the early gleams of those doc¬
trines which he held to be important truths.
In the conclusion of his survey, he speaks of the
spirit of speculation on this subject, as all but ex¬
tinct in this country. I would willingly believe
that this is too desponding a view of the fortunes
of moral philosophy among us ;—that the youth
of England are far from indifferent to the ques¬
tions which concern the nature and laws of man’s
highest faculties, and which excite a vigorous and
generous love of speculation in other parts of
Europe. To such a result I look forward the more
gladly, because I do not doubt that the reigning
philosophy of any age, even when it excites little
direct attention, influences powerfully men’s con¬
victions and habits of thought; and I am persuad¬
ed that we cannot make the prevalent views of
morals sounder, purer, and more philosophical,
without improving the general intellectual and
moral character of the educated classes of the na¬
tion.
W. W.
DISSERTATION SECOND
INTRODUCTION.
The inadequacy of the words of ordinary lan¬
guage for the purposes of Philosophy, is an an¬
cient and frequent complaint; of which the just¬
ness will he felt by all who consider the state to
which some of the most important arts would
be reduced, if the coarse tools of the common
labourer were the only instruments to be em¬
ployed in the most delicate operations of ma¬
nual expertness. The watchmaker, the opti¬
cian, and the surgeon, are provided with instru¬
ments which are fitted, by careful ingenuity, to
second their skill; the philosopher alone is
doomed to use the rudest tools for the most re¬
fined purposes. He must reason in words of
which the looseness and vagueness are suitable,
and even agreeable, in the usual intercourse of
life, but which are almost as remote from the
extreme exactness and precision required, not
only in the conveyance, but in the search of
truth, as the hammer and the axe would be un¬
fit for the finest exertions of skilful handiwork;
for it is not to be forgotten, that he must him¬
self think in these gross words as unavoidably
as he uses them in speaking to others. He is
in this respect in a worse condition than an as¬
tronomer who looked at the heavens only with
the naked eye, whose limited and partial obser¬
vation, however it might lead to error, might
not directly, and would not necessarily deceive.
He might, be more justly compared to an arith¬
metician compelled to employ numerals not only
cumbrous, but used so irregularly to denote dif¬
ferent quantities, that they not only often de¬
ceived others, but himself.
The Natural Philosopher and Mathematician
have in some degree the privilege of framing
their own terms of art; though that liberty is
daily narrowed by the happy diffusion of these
great branches of knowledge, which daily mixes
their language with the general vocabulary of
educated men. The cultivator of Mental and
Moral Philosophy can seldom do more than
mend the faults of his words by definition; a
necessary but very inadequate expedient, in a
great measure defeated in practice by the un¬
avoidably more frequent recurrence of the terms
in their vague than in their definite acceptation;
in consequence of which the mind, to which the
310
PRELIMINARY DISSERTATIONS.
definition is faintly and but occasionally present,
naturally suffers, in the ordinary state of atten¬
tion, the scientific meaning to disappear from
remembrance, and insensibly ascribes to the
word a great part, if not the whole, of that po¬
pular sense which is so very much more familiar
even to the most veteran speculator. The ob¬
stacles which stood in the way of Lucretius and
Cicero, when they began to translate the subtile
philosophy of Greece into their narrow and bar¬
ren tongue, are always felt by the philosopher
when he struggles to express, with the neces¬
sary discrimination, his abstruse reasonings in
words which, though those of his own language,
be must take from the mouths of those to whom
his distinctions would be without meaning.
The Moral Philosopher is in this respect sub¬
ject to peculiar difficulties. His statements and
reasonings often call for nicer discriminations
of language than those which are necessary in
describing or discussing the purely intellectual
part of human nature; but his freedom in the
choice of words is more circumscribed. As he
treats of matters on which all men are disposed
to form a judgment, he can as rarely hazard
glaring innovations in diction, at least in an
adult and mature language like ours, as the ora¬
tor or the poet. If he deviates from common
use, he must atone for his deviation by hiding
it, and can only give a new sense to an old word
by so skilful a position of it as to render the
new meaning so quickly understood that its no¬
velty is scarcely perceived. Add to this, that
in those most difficult inquiries for which the
utmost coolness is not more than sufficient, he
is often forced to use terms commonly connect¬
ed with warm feeling, with high praise, with
severe reproach; which excite the passions of his
readers when he most needs their calm atten¬
tion and the undisturbed exercise of their im¬
partial judgment. There is scarcely a neutral
term left in Ethics ; so quickly are such expres¬
sions enlisted on the side of Praise or Blame,
by the address of contending passions. A true
philosopher must not even desire that men
should less love virtue or hate vice, in order to
fit them for a more unprejudiced judgment on
his speculations.
There are perhaps not many occasions where
the penury and laxity of language are more felt
than in entering on the history of sciences where
the first measure must be to mark out the boun¬
dary of the whole subject with some distinct¬
ness. But no exactness in these important ope¬
rations can be approached without a new divi¬
sion of human knowledge, adapted to the pre¬
sent stage of its progress, and a reformation of
all those barbarous, pedantic, unmeaning, and
(what is worse) wrong-meaning names which
continue to be applied to the greater part of its
branches. Instances are needless where nearly
all the appellations are faulty. The term Me¬
taphysics affords a specimen of all the faults
which the name of a science can combine. To
those who know only their own language, it
must, at their entrance on the study, convey no
meaning. It points their attention to nothing.
If they examine the language in which its parts
are significant, they will be misled into the per¬
nicious error of believing that it seeks some¬
thing more than the interpretation of nature.
It is only by examining the history of ancient
Philosophy that the probable origin of this name
will be found, in the application of it, as the
running title of several essays of Aristotle,
which were placed in a collection of the manu¬
scripts of that great philosopher, after his trea¬
tise on Physics. It has the greater fault of an
unsteady and fluctuating signification ; denoting
one class of objects in the seventeenth century,
and another in the eighteenth—even in the
nineteenth not quite of the same import in the
mouth of a German, as in that of a French or
English philosopher; to say nothing of the far¬
ther objection that it continues to be a badge of
undue pretension among some of the followers
of the science, while it has become a name
of reproach and derision among those who alto¬
gether decry it.
The modern name of the very modern science
called Political Economy, though deliberately
bestowed on it by its most eminent teachers, is
perhaps a still more notable sample of the like
faults. It might lead the ignorant to confine it
to retrenchment in national expenditure ; and a
consideration of its etymology alone would lead
into the more mischievous error of believing it
to teach, that national wealth is best promoted by
DISSERTATION SECOND.
311
the contrivance and interference of lawgivers,
in opposition to its surest doctrine, which it
most justly boasts of having discovered and en¬
forced.
It is easy to conceive an exhaustive analysis
of Human Knowledge, and a consequent division
of it into parts corresponding to all the classes
of objects to which it relates:—a representation
of that vast edifice, containing a picture of what
is finished, a sketch of what is building, and
even a conjectural outline of what, though re¬
quired by completeness and convenience, as well
as symmetry, is yet altogether untouched. A
system of names might also be imagined derived
from a few roots, indicating the objects of each
part, and showing the relation of the parts to
each other. An order and a language somewhat
resembling those by which the objects of the
sciences of Botany and Chemistry have, in the
eighteenth century, been arranged and denoted,
are doubtless capable of application to the sciences
generally, when considered as parts of the system
of knowledge. The attempts, however, which
have hitherto been made to accomplish the ana¬
lytical division of knowledge which must neces¬
sarily precede a new nomenclature ot the sciences,
have required so prodigious a superiority of ge¬
nius in the single instance of approach to success
by Bacon, as to discourage rivalship nearly as
much as the frequent examples of failure in sub¬
sequent times. The nomenclature itself is at¬
tended with great difficulties, not indeed in its
conception, but in its adoption and usefulness.
In the Continental languages to the south of
the Rhine, the practice of deriving the names of
science from Greek must be continued; which
would render the new names for a while unin¬
telligible to the majority of men. Even in Ger¬
many, where a flexible and fertile language
affords unbounded liberty of derivation and com¬
position from native roots or elements, and where
the newly derived and compounded words would
thus be as clear to the mind, and almost as
little startling to the ear of every man, as the
oldest terms in the language, yet the whole no¬
menclature would be unintelligible to other na¬
tions. The intercommunity of the technical
terms of science in Europe has been so far broken
down by the Germans, and the influence of their
literature and philosophy is so rapidly increasing
in the greater part of the Continent, that though
a revolution in scientific nomenclature be pro¬
bably yet far distant, tbe foundation of it may
be considered as already prepared.
But although so great an undertaking must
be reserved for a second Bacon and a future
generation, it is necessary for the historian of
any branch of knowledge to introduce his work
by some account of the limits and contents of
the sciences of which he is about to trace the
progress; and though it will be found impos¬
sible to trace throughout the treatise a distinct
line of demarcation, yet a general and imperfect
sketch of the boundaries of the whole, and of
the parts of our present subject, may be a con¬
siderable help to the reader, as it has been a
useful guide to the writer.
There is no distribution of the parts of know¬
ledge more ancient than that of the Physical
and Moral Sciences, which seems liable to no
other objection, than that it does not exhaust
the subject. Even this division, however, can¬
not be safely employed, without warning the
reader, that no science is entirely insulated,
and that the principles of one are often only the
conclusions and results of another. Every
branch of knowledge has its root in the theory
of the Understanding, from which even the ma¬
thematician must learn what can be known of
his magnitude and his numbers; and Moral
Science is founded on that other hitherto un¬
named part of the philosophy of human nature
(to be constantly and vigilantly distinguished
from Intellectual Philosophy), which contem¬
plates the laws of sensibility, of emotion, of
desire and aversion, of pleasure and pain, of
happiness and misery; and on which arise the
august and sacred landmarks that stand con¬
spicuous along the frontier between Right and
Wrong.
But however multiplied the connections of
the Moral and Physical Sciences are, it is not
difficult to draw a general distinction between
them. The purpose of the Physical Sciences
throughout all their provinces, is to answer the
question What is ? They consist only of facts
arranged according to their likeness, and ex¬
pressed by general names given to every class
312
PRELIMINARY DISSERTATIONS.
of similar facts. The purpose of the Moral
Sciences is to answer the question What ought
to be ? They aim at ascertaining the rules
which ought to govern voluntary action, and to
which those habitual dispositions of mind which
are the source of voluntary actions ought to be
adapted.
It is obvious that Will, Action, Habit, Disposi¬
tion, are terms denoting facts in human nature,
and that an explanation of them must he sought
in Mental Philosophy; which, if knowledge he
divided into Physical and Moral, must he placed
among physical sciences; though it essentially
differs from them all in having for its chief ob-
lect those laws of thought which alone render
any other sort of knowledge possible. But it is
equally certain that the word Ought introduces
the mind into a new region, to which nothing
physical corresponds. However philosophers
may deal with this most important of words, it
is instantly understood by all who do not at¬
tempt to define it. No civilized speech, perhaps
no human language, is without correspondent
terms. It would he as reasonable to deny that
Space and Greenness are significant words, as to
affirm that Ought, Right, Duty, Virtue, are sounds
without meaning. It would he fatal to an Ethi¬
cal Theory that it did not explain them, and
that it did not comprehend all the conceptions
and emotions which they call up. There never
yet was a theory which did not attempt such an
explanation.
SECTION I.
Preliminary Observations.
There is no man who, in a case where he
was a calm hy-stander, would not look with
more satisfaction on acts of kindness than on
acts of cruelty. No man, after the first excite¬
ment of his mind has subsided, ever whispered
to himself with self-approbation and secret joy
that he had been guilty of cruelty or baseness.
Every criminal is strongly impelled to hide these
qualities of his actions from himself, as he would
do from others, by clothing his conduct in some
disguise of duty or of necessity. There is no
tribe so rude as to he without a faint perception
of a difference between right and wrong. There
is no subject on which men of all ages and na¬
tions coincide in so many points as in the gene¬
ral rules of conduct, and in the qualities of the
human character which deserve esteem. Even
the grossest deviations from the general consent
will appear, on close examination, to he not so
much corruptions of moral feeling, as either ig¬
norance of facts; or errors with respect to the
consequences of action; or cases in which the
dissentient party is inconsistent with other parts
of his own principles, which destroys the value
of his dissent; or where each dissident is con¬
demned by all the other dissidents, which im¬
measurably augments the majority against him.
In the first three cases he may he convinced by
argument, that his moral judgment should he
changed on principles which he recognises as
just; and he can seldom, if ever, be condemned
at the same time by the body of mankind who
agree in their moral systems, and by those who
on some other points dissent from that general
code, without being also convicted of error by
inconsistency with himself. The tribes who ex¬
pose new-horn infants, condemn those who
abandon their decrepit parents to destruction.
Those who betray and murder strangers, are
condemned by the rules of faith and humanity
which they acknowledge in their intercourse
with their countrymen. Mr Hume, in a dia¬
logue in which he ingeniously magnifies the
moral heresies of two nations so polished as the
Athenians and the French, has very satisfactorily
resolved his own difficulties. “ In how many cir¬
cumstances would an Athenian and a Frenchman
of merit certainly resemble each other?—Human-
DISSERTATION SECOND.
313
ity, fidelity, truth, justice, courage, temperance,
constancy, dignity of mind The principles
upon which men reason in morals are always the
same, though their conclusions are often very dif¬
ferent.” 1 He might have added, that almost every
deviation which he imputes to each nation is at
variance with some of the virtues justly esteemed
by both; and that the reciprocal condemnation
of each other’s errors which appears in his
statement entitles us on these points to strike
out the suffrages of both, when collecting the
general judgment of mankind. If we hear in
mind that the question relates to the coincidence
of all men in considering the same qualities as
virtues, and not to the preference of one class
of virtues by some, and of a different class by
others, the exceptions from the agreement of
mankind, in their system of practical morality,
will he reduced to absolute insignificance; and
we shall learn to view them as no more affecting
the harmony of our moral faculties, than the re¬
semblance of the limbs and features is affected
by monstrous conformations, or by the unfortu¬
nate effects of accident and disease in a very
few individuals.*
It is very remarkable, however, that though
all men agree that there are acts which ought
to be done, and acts which ought not to be done ;
though the far greater part of mankind agree in
their list of virtues and duties, of vices and
crimes; and though the whole race, as it advances
in other improvements, is as evidently tending
towards the moral system of the most civilized
nations, as children in their growth tend to the
opinions as much as to the experience and
strength of adults; yet there are no questions
in the circle of inquiry to which answers more
various have been given than—How men have
thus come to agree in the rule of life; Whence
arises their general reverence for it; and What
is meant by affirming that it ought to be in¬
violably observed ? It is singular, that where
we are most nearly agreed respecting rules, we
should perhaps most differ as to the causes of
our agreement, and as to the reasons which
justify us for adhering to it. The discussion of
these subjects composes what is usually called
the Theory of Morals, in a sense not in all
respects coincident with what is usually con¬
sidered as Theory in other sciences. When we
investigate the causes of our moral agreement,
the term Theory retains its ordinary scientific
sense; but when we endeavour to ascertain the
reasons of it, we rather employ the term as im¬
porting the theory of the rules of an art. In
the first case, Theory denotes, as usual, the
most general laws to which certain facts can be
reduced; whereas in the second, it points out
the efficacy of the observance, in practice, of
certain rules, for producing the effects intended
to be produced in the art. These reasons also
may be reduced under the general sense by stat¬
ing the question relating to them thus What
are the causes why the observance of certain
rules enables us to execute certain purposes ?
An account of the various answers attempted to
be made to these inquiries, properly forms the
History of Ethics.
The attentive reader may already perceive,
that these momentous inquiries relate to at least
two perfectly distinct subjects : 1. The nature
of the distinction between right and wrong in
human conduct, and 2. The nature of those feel¬
ings with which right and wrong are contem¬
plated by human beings. The latter consti¬
tutes what has been called the Theory of Mo¬
ral Sentiments; the former consists in an in¬
vestigation into the Criterion of Morality in
action. Other most important questions arise
in this province. But the two problems which
have been just stated, and the essential distinc¬
tion between them, must he clearly apprehended
1 Philosophical Works, vol. IV. p. 420, 422. Edinb. 1826. , . ,
* u On convient le plus souvent de ces instincts de la conscience. La plus grande et la plus same partie du genre u-
main leur rend temoignage. Les Orientaux, et les Grecs, et les Romains conviennent en cela; et il faudroit etre aussi
abruti que les sauvages Americains pour approuver leurs coutumes, pleines d une cruaute qui passe menie celle des be es.
Cependant ces memes sauvages sentent Men ce que c'est que la justice en d'autres occasions ; et quoique il n y ait point de mauyaise
pratique peut-etre qui ne soit autorisee quelque part, il y en a peu pourtant qui ne soient condamnees le plus souvent, e par
la plus grande partie des hommes.” (Leibnitz, CEuvres Philosophiques, p. 49. Amst. et Leipz. 17b5, 4to.)
There are some admirable observations on this subject in Hartley, especially in the development of the 49th 1 roPosl;
tion. “ The rule of life drawn from the practice and opinions of mankind corrects and improves itself perpetually, till at lust it
determines entirely for virtue, and excludes all kinds and degrees of vice." (Obserxmtions on Man, I. 207-)
314
PRELIMINARY DISSERTATIONS.
by all who are desirous of understanding the
controversies which have prevailed on ethical
subjects. The discrimination has seldom been
made by Moral Philosophers; the difference
between the two problems has never been uni¬
formly observed by any of them: and it will
appear, in the sequel, that they have been not
rarely altogether confounded by very eminent
men, to the destruction of all just conception
and of all correct reasoning in this most import¬
ant, and perhaps most difficult of sciences.
It may therefore be allowable to deviate so
far from lustorical order, as to illustrate the
nature and to prove the importance of the dis¬
tinction, by an example of the effects of ne¬
glecting it, taken from the recent works of
justly celebrated writers; in which they discuss
questions much agitated in the present age, and
therefore probably now familiar to most readers
of this Dissertation.
Dr Paley represents the principle of a moral
sense as being opposed to that of utility.1 Now,
it is evident that this representation is founded
on a confusion of the two questions which have
heen stated above. That we are endued with a
moral sense, or, in other words, a faculty which
immediately approves what is right and con¬
demns what is wrong, is only a statement of
the feelings with which we contemplate actions.
But to affirm that right actions are those which
conduce to the wellbeing of mankind, is a pro¬
position concerning the outward effects by
which right actions themselves may be recog¬
nised. As these affirmations relate to different
subjects, they cannot be opposed to each other,
any more than the solidity of earth is inconsist¬
ent with the fluidity of water; and a very little
reflection will show it to be easily conceivable
that they may be both true. Man may be so
constituted as instantaneously to approve cer¬
tain actions without any reference to their con¬
sequences ; and yet reason may nevertheless
discover, that a tendency to produce general
happiness is the essential characteristic of such
actions. Mr Bentham also contrasts the prin¬
ciple of utility with that of sympathy, of which
he considers the moral sense as being one of the
forms.2 3 It is needless to repeat, that proposi¬
tions which affirm or deny anything of different
subjects, cannot contradict each other. As
these celebrated persons have thus inferred or
implied the non-existence of a moral sense,
from their opinion that the morality of actions
depends upon their usefulness, so other philoso¬
phers of equal name have concluded, that the
utility of actions cannot be the criterion of
their morality, because a perception of that
utility appears to them to form a faint and in¬
considerable part of our moral sentiments, if
indeed it be at all discoverable in them.2 These
errors are the more remarkable, because the
like confusion of perceptions with their objects,
of emotions with their causes, or even the omis¬
sion to mark the distinctions, would, in every
other subject, be felt to be a most serious fault
in philosophizing. If, for instance, an element
were discovered to be common to all bodies
which our taste perceives to be sweet, and to be
found in no other bodies, it is apparent that this
discovery, perhaps important in other respects,
would neither affect our perception of sweet¬
ness, nor the pleasure which attends it. Both
would continue to be what they have been since
the existence of mankind. Every proposition
concerning that element would relate to sweet
bodies, and belong to the science of Chemistry;
while every proposition respecting the percep¬
tion or pleasure of sweetness would relate either
to the body or mind of man, and accordingly
belong either to the science of Physiology, or
to that of Mental Philosophy. During the
many ages which passed before the analysis of
the sun’s beams had proved them to be com¬
pounded of different colours, white objects were
seen, and their whiteness was sometimes felt to
be beautiful, in the very same manner as since
that discovery. The qualities of light are the
object of Optics; the nature of beauty can be as-
1 Principles of Moral and Political Philosophy. Compare book i. chap. v. with book ii. chap. vi.
2 Introduction to the Principles of Morality and Legislation, chap. ii.
3 Smith’s Theory of Moral Sentiments, Part iv. Even Hume, in the third book of his Treatise of Human Nature, the
most precise, perhaps, of his philosophical writings, uses the following as the title of one of the sections: “ Moral Dis¬
tinctions derived from a Moral Sense.''’
DISSERTATION SECOND.
315
certained only by each man’s observation of his
own mind; the changes in the living frame
which succeed the refraction of light in the eye,
and precede mental operation, will, if they are
ever to he known by man, constitute a part of
Physiology. But no proposition relating to
one of these orders of phenomena can contra¬
dict or support a proposition concerning another
order.
The analogy of this latter case will justify
another preliminary observation. In the case
of the pleasure derived from beauty, the ques¬
tion whether that pleasure be original or deriv¬
ed is of secondary importance. It has been
often observed that the same properties which
are admired as beautiful in the horse, contribute
also to his safety and speed; and they who in¬
fer that the admiration of beauty was originally
founded on the convenience of fleetness and
firmness, if they at the same time hold that the
usefulness is gradually effaced, and that the ad¬
miration of a certain shape at length rises in¬
stantaneously without reference to any purpose,
may, with perfect consistency, regard a sense of
beauty as an independent and universal prin¬
ciple of human nature. The laws of such a
feeling of beauty are discoverable only by self¬
observation. Those of the qualities which call
it forth are ascertained by examination of the
outward things which are called beautiful. But
it is of the utmost importance to bear in mind,
that he who contemplates the beautiful propor¬
tions of a horse, as the signs and proofs of secu¬
rity or quickness, and has in view these conve¬
nient qualities, is properly said to prefer the
horse for his usefulness, not for his beauty;
though he may choose him from the same out¬
ward appearance which pleases the admirer of
the beautiful animal. He alone who derives
immediate pleasure from the appearance itself,
without reflection on any advantages which it
may promise, is truly said to feel the beauty.
The distinction, however, manifestly depends,
not on the origin of the emotion, but on its ob¬
ject and nature when completely formed. Many
of our most important perceptions through the
eye are universally acknowledged to be acquired.
But they are as general as the original percep¬
tions of that organ ; they arise as independently
of our will, and human nature would be quite
as imperfect without them. An adult who did
not immediately see the different distances of
objects from his eye, would be thought by every
one to be as great a deviation from the ordinary
state of man as if he were incapable of distin¬
guishing the brightest sunshine from the dark¬
est midnight. Acquired perceptions and senti¬
ments may therefore be termed natural, as much
as those which are more commonly so called,
if they be as rarely found wanting. Ethical
theories can never be satisfactorily discussed by
those who do not constantly bear in mind, that
the question concerning the existence of a moral
faculty in man which immediately approves or
disapproves without reference to any further ob¬
ject, is perfectly distinct, on the one hand, from
that which inquires into the qualities thus ap¬
proved or disapproved; and on the other, from
an inquiry whether that faculty be derived from
other parts of our mental frame, or be itself one
of the ultimate constituent principles of human
nature.
SECTION II.
Retrospect of Ancient Ethics.
Inquiries concerning the nature of mind, ed the understanding of civilized men. Frag-
the first principles of knowledge, the origin ments of such speculation are handed down
and government of the world, appear to have from the legendary age of Greek philosophy,
been among the earliest objects which employ- In the remaining monuments of that more an-
316
preliminary dissertations.
cient form of civilisation wliich sprung up in
Asia, we see clearly that the Braminical philo¬
sophers, in times perhaps before the dawn of
western history, had run round that dark and
little circle of systems which an unquenchable
thirst of knowledge has since urged both the
speculators of ancient Greece and those of Chris¬
tendom to retrace. The wall of adamant which
bounds human inquiry has scarcely ever been
discovered by nny adventurer, until he was
roused by the shock which drove him back. It
is otherwise with the theory of morals. No
controversy seems to have arisen regarding it in
Greece, till the rise and conflict of the Stoical
and Epicurean schools; and the ethical disputes
of the modern world originated with the writings
of Hobbes about the middle of the seventeenth
century. Perhaps the longer abstinence from
debate on this subject may have sprung from
reverence for morality. Perhaps also, wheie
the world were unanimous in their practical
opinions, little need Avas felt of exact theoi y.
The teachers of morals were content with par¬
tial or secondary principles, with the combina¬
tion of principles not always reconcilable, even
with vague but specious phrases which in any
degree explained or seemed to explain the rules
of the art of life—which seemed at once too
evident to need investigation, and too venerable
to be approached by controversy.
Perhaps the subtile genius of Greece was in
part withheld from indulging itself in ethical
controversy by the influence of Socrates, who
was much more a teacher of virtue than even a
searcher after truth—
Whom, well inspired, the oracle pronounced
Wisest of men.
It was doubtless because he chose that better
part that he was thus spoken of by the man
whose commendation is glory, and who, from
the loftiest eminence of moral genius ever
reached by a mortal, was perhaps alone worthy
to place a new crown on the brow of the mar¬
tyr of virtue.
Aristippus indeed, a wit and a worldling, bor¬
1 Diog. Laert. vi. jElian. ix. 35.
2 Heusde, Initia Philosoph. Plat. 1827 ; a hitherto h
excuse the partiality which belongs to a labour of love.
rowed nothing from the conversations of So¬
crates but a few maxims for husbanding the
enjoyments of sense. Antisthenes also, a hearer
but not a follower, founded a school of parade
and exaggeration, which caused his master to
disown him by the ingenious rebuke, “ I see
your vanity through your threadbare cloak.”1
The modest doubts of the most sober of moralists,
and his indisposition to fruitless abstractions,
were in process of time employed as the foun¬
dation of systematic scepticism; the most pre¬
sumptuous, inapplicable, and inconsistent of all
the results of human meditation. But though
his lessons were thus distorted by the perverse
ingenuity of some who heard him, the authority
of his practical sense may be traced in the mo¬
ral writings of those most celebrated philosophers
who were directly or indirectly his disciples.
Plato, the most famous of his scholars, the most
eloquent of Grecian writers, and the earliest
moral philosopher whose writings have come
down to us, employed his genius in the compo¬
sition of dialogues, in which his master per¬
formed the principal part. These beautiful
conversations would have lost their charm of
verisimilitude, of dramatic vivacity, of pictu¬
resque representation of character, if they had
been subjected to the constraint of method.
They necessarily presuppose much oral instruc¬
tion. They frequently quote, and doubtless
oftener allude to the opinions of predecessors
and contemporaries whose works have perished,
and of whose doctrines only some fragments are
preserved.
In these circumstances, it must be difficult
for the most learned and philosophical of his
commentators to give a just representation of
his doctrines, if he really framed or adopted a
system. The moral part of his works is more
accessible.2 The vein of thought which runs
through them is always visible. The object is
to inspire the love of truth, of wisdom, of beauty,
especially of goodness the highest beauty, and
of that supreme and eternal mind, which con¬
tains all truth and wisdom, all beauty and good-
work of great perspicuity and elegance, in which we must
DISSERTATION SECOND.
317
ness. By tlie love or delightful contemplation
and pursuit of these transcendent aims for their
own sake only, he represented the mind of man
as raised from low and perishable objects, and
prepared for those high destinies which are ap¬
pointed for all those who are capable of them.
The application to moral qualities of terms
which denote outward beauty, though by him
perhaps carried to excess, is an illustrative me¬
taphor, as well warranted by the poverty of lan¬
guage as any other employed to signify the acts
or attributes of mind.1 The beautiful in his
language denoted all that of which the mere
contemplation is in itself delightful, without any
admixture of organic pleasure, and without being
regarded as the means of attaining any farther
end. The feeling which belongs to it he called
love; a word which, as comprehending compla¬
cency, benevolence, and affection, and reaching
from the neighbourhood of the senses to the most
sublime of human thoughts, is foreign from the
colder and more exg.ct language of our philoso¬
phy ; but which perhaps then happily served to
lure both the lovers of poetry and the votaries
of superstition to the school of truth and good¬
ness in the groves of the Academy. He enforced
.these lessons by an inexhaustible variety of just
and beautiful illustrations,—sometimes striking
from their familiarity, sometimes subduing by
their grandeur; and his works are the store¬
house from which moralists have from age to
age borrowed the means of rendering moral in¬
struction easier and more delightful. Virtue he
represented as the harmony of the whole soul;—
as a peace between all its principles and desires,
assigning to each as much space as they can oc¬
cupy, without encroaching on each other;—as a
state of perfect health, in which every function
was performed with ease, pleasure, and vigour ;
—as a well-ordered commonwealth, where the
obedient passions executed with energy the laws
and commands of reason. The vicious mind
presented the odious character, sometimes of dis¬
cord, of war;—sometimes of disease;—always of
passions warring with each other in eternal
anarchy. Consistent with himself, and at peace
with his fellows, the good man felt in the quiet
of his conscience a foretaste of the approbation
of God. “ Oh what ardent love would virtue
inspire if s|ie could be seen.” “ If the heart of
a tyrant could be laid bare, we should see how
it was cut and torn by its own evil passions and
by an avenging conscience.” 2 * * * * *
Perhaps in every one of these illustrations, an
eye trained in the history of Ethics may discover
the germ of the whole or of a part of some sub¬
sequent theory. But to examine it thus would
not be to look at it with the eye of Plato. His
aim was as practical as that of Socrates. He
employed every topic, without regard to its
place in a system, or even always to its force as
argument, which could attract the small portion
of the community then accessible to cultivation;
who, it should not be forgotten, had no moral
instructor but the philosopher, unaided, if not
thwarted, by the reigning superstition: for reli¬
gion had not then, besides her own discoveries,
brought down the most awful and the most
beautiful forms of moral truth to the humblest
station in human society.8
Ethics retained her sober spirit in the hands
of his great scholar and rival Aristotle, who,
1 The most probable etymology of seems to be from to burn. What burns commonly shines. Schon, in Ger¬
man, which means beautiful, is derived from scheinen, to shine. The word was used for right, so early as the Home¬
ric Poems. II. xvii. 19. In the philosophical age it became a technical term, with little other remains of the metaphorical
sense than what the genius and art of a fine writer might sometimes rekindle. Honestum, the term by which Cicero
translates the *«Xav, being derived from outward honours, is a less happy metaphor. In our language, the terms being from
foreign roots, contribute nothing to illustrate the progress of thought. _ ., , , t>i . ™ \ • u ^
2 Let it not be forgotten, that for this terrible description, Socrates, to whom it is ascribed by Plato (Z)e Rep. ix.) is called
“ Prcestantissimus sapiential,” by a writer of the most masculine understanding, the least subject to be transported by en¬
thusiasm. (Tac. Ann. vi. 6.) “ Quae vulnera ! ” says Cicero, in alluding to the same passage. (Z)e Officus, m. 21.)
1 There can hardly be a finer example of Plato’s practical morals than his observations on the treatment of slaves.
Genuine humanity and real probity, says he, are brought to the test, by the behaviour of a man to slaves, w om e may
wrong with impunity. i part, pn ™ p.,<ru» h ovru; to tv tovtoh tv as
U'Siov admin. (Pi.ato de Legibus, lib. vi. edit. Bipont. VIII. 303.) . . tt -r.
That Plato was considered as the fountain of ancient morals, would be sufficiently evident from icero a one.
igitur Platonis, quasi quodam sancto augustoque fonte, nostra omnis manabit oratio.’ _ (Tusc. v* v j .
sober Quintilian meant to mingle some censure with the highest praise : “ Plato, qui eloquendi fiiculta. e q
et Homerica, multum supra prosam orationem surgit.” {Inst. Orat. x. I.)
318
PRELIMINARY DISSERTATIONS.
though he certainly surpassed all men in acute
distinction, in suhtile argument, in severe me¬
thod, in the power of analyzing what is most
compounded, and of reducing to simple prin¬
ciples the most various and unlike appearances,
yet appears to be still more raised above his fel¬
lows by the prodigious faculty of laying aside
these extraordinary endowments whenever his
present purpose required it; as in his History of
Animals, in his Treatises on Philosophical Cri¬
ticism, and in his Practical Writings, political
as well as moral. Contrasted as his genius was
to that of Plato, not only by its logical and me¬
taphysical attributes, hut by the regard to ex¬
perience and observation of nature which, in
him perhaps alone, accompanied them;—though
they may be considered as the original represen¬
tatives of the two antagonist tendencies of Phi¬
losophy—that which would ennoble man, and
that which seeks rather to explain nature; yet
opposite as they are in other respects, the mas¬
ter and the scholar combine to guard the Rule
of Life against the licentious irruptions of the
Sophists.
In Ethics alone their systems differed more in
words than in things.1 That happiness con¬
sisted in virtuous pleasure, chiefly dependent on
the state of mind, but not unaffected by outward
agents, was the doctrine of both. Both would
with Socrates have called Happiness “ unre¬
pented Pleasure.” Neither distinguished the
two elements which they represented as consti¬
tuting the supreme good from each other; part¬
ly, perhaps, from a fear of appearing to separate
them. Plato more habitually considered happi¬
ness as the natural fruit of virtue; Aristotle
oftener viewed virtue as the means of attaining
happiness. The celebrated doctrine of the Peri¬
patetics, which placed all virtues in a medium
between opposite vices, was probably suggested
by the Platonic representation of its necessity
to keep up harmony between the different parts
of our nature. The perfection of a compound
machine is attained where all its parts have the
fullest scope for action. Where one is so far
exerted as to repress others, there is a vice of
excess. When any one has less activity than it
might exert without disturbing others, there is
a vice of defect. The point which all reach
without collision against each other, is the me¬
diocrity in which the Peripatetics placed virtue.
It was not till near a century after the death
of Plato that Ethics became the scene of philo¬
sophical contest between the adverse schools of
Epicurus and Zeno; whose errors afford an in¬
structive example, that in the formation of the¬
ory, partial truth is equivalent to absolute
falsehood. As the astronomer who left either
the centripetal or the centrifugal force of the
planets out of his view, would err as completely
as he who excluded both, so the Epicureans and
Stoics, who each confined themselves to real but
not exclusive principles in morals, departed as
widely from the truth as if they had adopted no
part of it. Every partial theory is indeed di¬
rectly false, inasmuch as it ascribes to one or
few causes what is produced by more. As the
extreme opinions of one if not both of these
schools have been often revived with variations
and refinements in modern times, and are still
not without influence on ethical systems, it may
be allowable to make some observations on this
earliest of moral controversies.
“ All other virtues,” said Epicurus, “ grow
from prudence, which teaches that we cannot live
pleasurably without living justly and virtuously,
nor live justly and virtuously without living plea¬
surably.”2 The illustration of this sentence
formed the whole moral discipline of Epicurus.
To him we owe the general concurrence of reflect¬
ing men in succeeding times, in the important
truth, that men cannot he happy without a vir¬
tuous frame of mind and course of life; a truth
of inestimable value, not peculiar to the Epicu¬
reans, but placed by their exaggerations in a
stronger light;—a truth, it must be added, of
1 “ Una et consentiens duobus vocabulis philosophise forma instituta est, Academicorum et Peripateticorum ; qui rebus
congruentes, nominibus differebant. (ClC. Acad. Qucest. i. 4 ) RovXtrm (AoirrranXrii) 'iirrav uioli rov Kctrx QiAeffotyixt XoyW rot
fitv or/iaZTixov, rov os heo^nrixov. xai rou ot^ocxtikov, tov rs ythxov Xai voXiTixof <rou Is HeupnTixov, rev ri 0emxov »«/ Xeytxev. fDlOG
Laert. V. 28.) ^ > r / v •
* Eric. Epist. ad Menccc. apud Diog. Laert. lib. x. edit. Meibom. I. 658, 656.
DISSERTATION SECOND.
319
less importance as a motive to right conduct
than to the completeness of Moral Theory,
which, however, it is very far from solely con¬
stituting. With that truth the Epicureans
blended another position, which indeed is con¬
tained in the first words of the above statement;
namely, that because virtue promotes happi¬
ness, every act of virtue must be done in order
to promote the happiness of the agent. They
and their modern followers tacitly assume, that
the latter position is the consequence of the for¬
mer; as if it were an inference from the necessity
of food to life, that the fear of death should he
substituted for the appetite of hunger as a mo¬
tive for eating. “ Friendship,” says Epicurus,
“ is to be pursued by the wise man only for its
usefulness, hut he will begin as he sows the
field in order to reap.”1 It is obvious, that if
these words he confined to outward benefits,
they may be sometimes true, but never can be
pertinent; for outward acts sometimes show
kindness, but never compose it. If they be ap¬
plied to kind feeling they would indeed be per¬
tinent, but they would be evidently and totally
false; for it is most certain that no man ac¬
quires an affection merely from his belief that
it would be agreeable or advantageous to feel it.
Kindness cannot indeed be pursued on account
of the pleasure which belongs to it; for man
can no more know the pleasure till he has felt
the affection, than he can form an idea of colour
without the sense of sight. The moral charac¬
ter of Epicurus was excellent; no man more
enjoyed the pleasure or better performed the
duties of friendship. The letter of his system
was no more indulgent to vice than that of any
other moralist.2 Although, therefore, he has
the merit of having more strongly inculcated
the connection of virtue with happiness, perhaps
by the faulty excess of treating it as an exclu¬
sive principle; yet his doctrine was justly
charged with indisposing the mind to those
exalted and generous sentiments, without which
no pure, elevated, bold, generous, or tender
virtues can exist.5
As Epicurus represented the tendency of vir¬
tue, which is a most important truth in ethical
theory, as the sole inducement to virtuous
practice; so Zeno, in his disposition towards
the opposite extreme, was inclined to consider
the moral sentiments which are the motives
of right conduct, as being the sole principles
of moral science. The confusion was equally
great in a philosophical view; but that of Epi¬
curus was more fatal to interests of higher im¬
portance than those of philosophy. Had the
Stoics been content with affirming that virtue
is the source of all that part of our happiness
which depends on ourselves, they would have
taken a position from which it would have been
impossible to drive them; they would have laid
down a principle of as great comprehension in
practice as their wider pretensions; a simple
and incontrovertible truth, beyond which every
thing is an object of mere curiosity to man.
Our information, however, about the opinions
of the more celebrated Stoics is very scanty.
None of their own writings are preserved. We
know little of them but from Cicero, the trans¬
lator of Grecian philosophy, and from the Greek
compilers of a later age; authorities which
would be imperfect in the history of facts, but
which are of far less value in the history of
opinions, where a right conception often depends
upon the minutest distinctions between words.
We know that Zeno was more simple, and that
Chrysippus, who was accounted the prop of the
Stoic Porch, abounded more in subtile distinc¬
tion and systematic spirit.4 His power was at¬
tested as much by the antagonists whom he call¬
ed forth, as by the scholars whom he formed.
“ Had there been no Chrysippus, there would
T„v ha ms (Diog. Laert. ibid.) “ Hie est locus,” Gassendi confesses, “ ob quern Epicurus non
parum yexatur, quando nemo non reprehendit, parari amicitiam non sui, sed utilitatis gratia.”
2 It is due to him to observe, that he treated humanity towards slaves, as one of the characteristics of a wise man.
uts xoXaffuv oiKirx;, iXttieruv fttv >roi, xxi mi’yyviu/xnv rm rm traroubaiwv. (DlOG. LiAERT. ibid. 653.) It is not unworthy of
remark, that neither Plato nor Epicurus thought it necessary to abstain from these topics in a city full of slaves, many of
whom were men not destitute of knowledge.
3 “ Nil generosum, nil magnificum sapit.” Cicero.
. . . Chrysippus, qui fulcire putatur porticum Stoicorum.” Cicero. Elsewhere, “ Acutissimus, sed in scribendo exilis
jejunus, senpsit rhetoricam seu potius obmutescendi artem;” nearly as we should speak of a Schoolman.
320
preliminary dissertations.
have been no Carneades,” was the saying of the
latter philosopher himself; as it might have been
said in the eighteenth century, 44 Had there been
no Hume, there would have been no Kant and
no Reid.” Cleanthes, when one of his followers
would pay court to him by laying vices to the
charge of his most formidable opponent, Arcesi-
laus the academic, answered with a justice and
candour unhappily too rare, 44 Silence, do not
malign him 5—though he attacks "virtue by his
arguments, he confirms its authority by his life.
Arcesilaus, whether modestly or churlishly, re¬
plied, I do not choose to be flattered.” Cleanthes,
with a superiority of repartee, as well as chari¬
ty, replied, 44 Is it flattery to say that you speak
one thing and do another ?” It would be vain
to expect that the fragments of the Professors
who lectured in the Stoic School for five hundred
years, should be capable of being moulded into
one consistent system ; and we see that in Epic¬
tetus at least, the exaggeration of the sect was
lowered to the level of reason, by confining the
sufficiency of virtue to those cases only where
happiness is attainable by our voluntary acts.
It ought to be added, in extenuation of a noble
error, that the power of habit and character to
struggle against outward evils has been proved
by experience to be in some instances so prodi¬
gious, that no man can presume to fix the ut¬
most limit of its possible increase.
The attempt, however, of the Stoics to stretch
the bounds of their system beyond the limits of
nature, produced the inevitable inconvenience
of dooming them to fluctuate between a wild
fanaticism on the one hand, and, on the other,
concessions which left their differences from
other philosophers pure ly verbal. Many of their
doctrines appear to be modifications of their
original opinions, introduced as opposition be¬
came more formidable. In this manner they
were driven to the necessity of admitting that
the objects of our desires and appetites are
worthy of preference, though they are denied
to be constituents of happiness. It was thus
that they were obliged to invent a double mo¬
rality; one for mankind at large, from whom
was expected no more than the mOrixov,—which
seems principally to have denoted acts of duty
done from inferior or mixed motives; and the
other, which they appear to have hoped from
their ideal wise man, is xarogOupa, or perfect
observance of rectitude,—which consisted only
in moral acts done from mere reverence for
morality, unaided by any feelings; all which
(without the exception of pity) they classed
among the enemies of reason and the disturbers
of the human soul. Thus did they shrink from
their proudest paradoxes into verbal evasions.
It is remarkable that men so acute did not per¬
ceive and acknowledge, that if pain were not
an evil, cruelty would not be a vice; and that if
patience were of power to render torture in¬
different, virtue must expire in the moment of
victory. There can be no more triumph when
there is no enemy left to conquer.1
The influence of men’s opinions on the con¬
duct of their lives is checked and modified by
so many causes—it so much depends on the
strength of conviction, on its habitual combina¬
tion with feelings, on the concurrence or resist¬
ance of interest, passion, example, and sympa¬
thy—that a wise man is not the most forward in
attempting to determine the power of its single
operation over human actions. In the case of
an individual it becomes altogether uncertain.
But when the experiment is made on a large
scale, when it is long continued and varied in
its circumstances, and especially when great
bodies of men are for ages the subject of it, we
cannot reasonably reject the consideration of
the inferences to which it appears to lead. The
Roman Patriciate, trained in the conquest and
government of the civilized world, in spite of
the tyrannical vices which sprung from that
training, were raised by the greatness of their
objects to an elevation of genius and character
unmatched by any other aristocracy; at the mo¬
ment when, after preserving their power by a
long course of wise compromise with the people,
they were betrayed by the army and the popu¬
lace into the hands of a single tyrant of their
own order—the most accomplished of usurpers,
1 “ Patience, sovereign o’er transmuted ill.” But as soon as the ill was really “ transmuted” into good, it is evident that
there was no longer any scope left for the exercise of patience.
DISSERTATION SECOND.
321
and, if humanity and justice could for a moment
be silenced, one of the most illustrious of men.
There is no scene in history so memorable as
that in which Caesar mastered a nobility of
which Lucullus and Hortensius, Sulpicius and
Catulus, Pompey and Cicero, Brutus and Cato,
were members. This renowned body had from
the time of Scipio sought the Greek philosophy
as an amusement or an ornament. Some few,
<c in thought more elevate,” caught the love of
truth, and were ambitious of discovering a solid
foundation for the Rule of Life. The influence
of the Grecian systems was tried by their effect
on a body of men of the utmost originality,
energy, and variety of character, during the five
centuries between Carneades and Constantine, in
their successive positions of rulers of the world,
and of slaves under the best and under the worst
of uncontrolled masters. If we had found this in¬
fluence perfectly uniform, we should have justly
suspected our own love of system of having in part
bestowed that appearance on it. Had there been
no trace of such an influence discoverable in so
great an experiment, we must have acquiesced
in the paradox, that opinion does not at all affect
conduct. The result is the more satisfactory,
because it appears to illustrate general tendency
without excluding very remarkable exceptions.
Though Cassius was an Epicurean, the true re¬
presentative of that school was the accomplished,
prudent, friendly, good-natured timeserver At-
ticus, the pliant slave of every tyrant, who could
kiss the hand of Antony, imbrued as it was in
the blood of Cicero. The pure school of Plato
sent forth Marcus Brutus, the signal humanity
of whose life was both necessary and sufficient
to prove that his daring breach of venerable
rules flowed only from that dire necessity which
left no other means of upholding the most sacred
principles. The Roman orator, though in spe¬
culative questions ho embraced that mitigated
doubt which allowed most ease and freedom to
his genius, yet in those moral writings where
his heart was most deeply interested, followed
the severest sect of philosophy, and became al¬
most a Stoic. If any conclusion may he ha¬
zarded from this trial of systems, the greatest
which history has recorded, we must not refuse
our decided though not undistinguishing pre¬
ference to that noble school which preserved
great souls untainted at the court of dissolute
and ferocious tyrants; which exalted the slave
of one of Nero’s courtiers to he a moral teacher
of aftertimes; which for the first, and hitherto
for the only time, breathed philosophy and jus¬
tice into those rules of law which govern the
ordinary concerns of every man; and which,
above all, has contributed, by the examples of
Marcus Porcius Cato and of Marcus Aurelius
Antoninus, to raise the dignity of our species,
to keep alive a more ardent love of virtue, and
a more awful sense of duty, throughout all ge¬
nerations. 1
4
The result of this short review of the practi¬
cal philosophy of Greece seems to be, that though
it was rich in rules for the conduct of life, and
in exhibitions of the beauty of virtue, and though
it contains glimpses of j ust theory and fragments
of perhaps every moral truth, yet it did not leave
behind any precise and coherent system; un¬
less we except that of Epicurus, who purchased
consistency, method, and perspicuity too dearly
by the sacrifice of truth, and by narrowing and
lowering his views of human nature, so as to
enfeeble, if not extinguish, all the vigorous mo¬
tives to arduous virtue. It is remarkable, that
while of the eight Professors who taught in the
Porch, from Zeno to Posidonius, everyone either
softened or exaggerated the doctrines of his pre¬
decessor ; and while the beautiful and reverend
philosophy of Plato had, in his own Academy,
degenerated into a scepticism which did not
spare morality itself, the system of Epicurus re¬
mained without change; and his disciples con¬
tinued for ages to show personal honours to his
memory, in a manner which may seem unac¬
countable among those who were taught to
measure propriety by a calculation of palpable
_1 Of all testimonies to the character of the Stoics, perhaps the most decisive is the speech of the vile sycophant Ca-
pito, in the mock impeachment of Thrasea Paetus, before a senate of slaves: “ Ut quondam C. Caesarem et M. Catonem,
ita nunc te, Nero, et Thraseam, avida discordiarum civitas loquitur...Ista secta Tuberones et Favonios, veteri quoque m-
publicae ingrata nomina, genuit.” (Tacit. Ann. xvi. 22.)
See Notes and Illustrations, note A.
DISS. II. 2 S
322 PRELIMINARY DISSERTATIONS.
and outward usefulness. This steady adhe¬
rence is in part doubtless attributable to the por¬
tion of truth which the doctrine contains; in
some degree perhaps to the amiable and unboast¬
ful character of Epicurus; not a little, it may
be, to the dishonour of deserting an unpopular
cause 5 but probably most of all to that mental
indolence which disposes the mind to rest in a
simple system, comprehended at a glance, and
easily falling in, both with ordinary maxims of
discretion, and with the vulgar commonplaces
of satire on human nature.1 When all instruc¬
tion was conveyed by lectures, and when one
master taught the whole circle of the sciences
in one school, it was natural that the attachment
of pupils to a Professor should be more devoted
than when, as in our times, he can teach only a
small portion of a knowledge spreading towards
infinity, and even in his own little province
finds a rival in every good writer who has treat¬
ed the same subject. The superior attachment
of the Epicureans to their master is not without
some parallel among the followers of similar
principles in our own age, who have also re¬
vived some part of that indifference to eloquence
and poetry which may be imputed to the habit
of contemplating all things in relation to happi¬
ness, and to (what seems its uniform effect) the
egregious miscalculation which leaves a multi¬
tude of mental pleasures out of the account. It
may be said, indeed, that the Epicurean doctrine
has continued with little change to the present
day ; at least it is certain that no other ancient
doctrine has proved so capable of being restored
in the same form among the moderns; and it
may be added, that Hobbes and Gassendi, as
well as some of our own contemporaries, are as
confident in their opinions, and as intolerant of
scepticism, as the old Epicureans. The resem¬
blance of modern to ancient opinions, concern¬
ing some of those questions upon which ethical
controversy must always hinge, may be a suf¬
ficient excuse for a retrospect of the Greek mo¬
rals ; which it is hoped will simplify and shorten
subsequent observation on those more recent
disputes which form the proper subject of this
discourse.
The genius of Greece fell with liberty. The
Grecian philosophy received its mortal wound
in the contests between scepticism and dogma¬
tism which occupied the schools in the age of
Cicero. The Sceptics could only perplex, and
confute, and destroy. Their occupation was
gone as soon as they succeeded. They had
nothing to substitute for what they overthrew;
and they rendered their own art of no further
use. They were no more than venomous ani¬
mals, who stung their victims to death, but also
breathed their last into the wound. A third
age of Grecian literature indeed arose at Alex¬
andria, under the Macedonian kings of Egypt;
laudably distinguished by exposition, criticism,
and imitation, sometimes abused for the pur¬
poses of literary forgery, still more honoured by
some learned and highly-cultivated poets, as
well as by diligent cultivators of history and
science; among whom some began about the
first preaching of Christianity to turn their
minds once more to that high philosophy which
seeks for the fundamental principles of human
knowledge. Philo, a learned and philosophical
Hebrew, one of the flourishing colony of his na¬
tion established in that city, endeavoured to re¬
concile the Platonic Philosophy with the Mosaic
Law and the Sacred Books of the Old Testa¬
ment. About the end of the second century,
when the Christians, Hebrews, Pagans, and va¬
rious other sects of semi or Pseudo-Christian
Gnostics appear to have studied in the same
schools, the almost inevitable tendency of doc¬
trines, however discordant, in such circum¬
stances to amalgamate, produced its full effect
under Ammonius Saccas; a celebrated Professor,
who, by selection from the Greek systems, the
Hebrew books, the oriental religions, and by some
of that concession to the rising spirit of Christi¬
anity, of which the Gnostics had set the example,
composed a very mixed system, commonly de-
1 The progress of commonplace satire on sexes or professions, and (he might have added) on nations, has been exquisitely
touched by Gray in his Remarks on Lydgate ; a fragment containing passages as finely thought and written as any in Eng¬
lish prose. (Ghay’s Works, Matthias’s edition, vol. I. p. 55.) General satire on mankind is still more absurd; for no in¬
vective can be so unreasonable as that which is founded on falling short of an ideal standard.
DISSERTATION SECOND.
323
signaled as the Eclectic Philosophy. The con¬
troversies between his contemporaries and fol¬
lowers, especially those of Clement and Ori-
gen, the victorious champions of Christianity,
with Plotinus and Porphyry, who endeavoured
to preserve Paganism by clothing it in a dis¬
guise of philosophical Theism, are, from the
effects towards which they contributed, the most
memorable in the history of human opinion.1 2 3 *
But their connection with modern ethics is too
faint to warrant any observation in this place,
on the imperfect and partial memorials of them
which have reached us. The death of Boethius
in the west, and the closing of the Athenian
schools by Justinian, may be considered as the
last events in the history of ancient philosophy.a
SECTION III.
Retrospect of Scholastic Ethics.
An interval of a thousand years elapsed be¬
tween the close of ancient and the rise of modern
philosophy; the most unexplored, yet not the
least instructive portion of the history of Euro¬
pean opinion. In that period the sources of the
institutions, the manners, the characteristic dis¬
tinctions of modern nations, have been traced
by a series of philosophical inquirers from Mon¬
tesquieu to Hal lam; and there also, it may be
added, more than among the ancients, are the
wellsprings of our speculative doctrines and
controversies. Far from being inactive, the hu¬
man mind, during that period of exaggerated
darkness, produced discoveries in science, in¬
ventions in art, and contrivances in government,
some of which, perhaps, were rather favoured
than hindered by the disorders of society, and
by the twilight in which men and things were
seen. Had Boethius, the last of the ancients,
foreseen, that within two centuries of his death,
in the province of Britain, then a prey to all
the horrors of barbaric invasion, a chief of one
of the fiercest tribes of barbarians should trans¬
late into the jargon of his freebooters the work
on The Consolations of Philosophy, of which the
composition had soothed the cruel imprisonment
of the philosophic Roman himself, he must, even
amidst his sufferings, have derived some grati¬
fication from such an assurance of the recovery
of mankind from ferocity and ignorance. But
had he been allowed to revisit the earth in the
middle of the sixteenth century, with what
wonder and delight might he have contemplated
the new and fairer order which was beginning
to disclose its beauty, and to promise more than
it revealed. He would have seen personal sla¬
very nearly extinguished, and women, first re¬
leased from oriental imprisonment by the Greeks,
and raised to a higher dignity among the Ro¬
mans,5 at length fast approaching to due equa¬
lity ; two revolutions the most signal and be¬
neficial since the dawn of civilisation. He
1 The change attempted by Julian, Porphyry, and their friends, by which Theism would have become the popular reli¬
gion, may be estimated by the memorable passage of Tacitus on the Theism of the Jews. In the midst of all the obloquy
and opprobrium with which he loads that people, his tone suddenly rises when he comes to contemplate them as the only
nation who paid religious honours to the supreme and eternal mind alone, and his style swells at the sight of so sublime and
wonderful a scene. “ Summum Ulud atque seternum, neque mutabile neque interiturum.”
2 The punishment of death was inflicted on Pagans by a law of Constantius. “ Volumus cunctos sacrificiis abstinere.
Si aliquid hujusmodi perpetraverint, gladio ultore sternantur.” (Cod. I. tit. xi. de Paganis, A. I). 343 or 346.) From the
authorities cited by Gibbon, (note, chap, xi.) as well as from some research, it should seem that the edict for the suppression
of the Athenian schools was not admitted into the vast collection of laws enacted or systematized by Justinian.
3 The steps of this important progress, as far as relates to Athens and Rome, are well remarked by one of the finest of
the Roman writers. “ Quern enim Romanorum pudet uxorem ducere in convivium ? aut cujus materfamilias non primum
locum tenet sedium, atque in celebritate versatur ? quod multo fit aliter in Graecia; nam neque in convivium adhibetur,
nisi propinquorum, neque sedet nisi in interiore parte aedium, quse Gynaeconitis appellatur, quo nemo accedit, nisi propinqua
cognatione conjunctus.” (Cornel. Nepos in Proefat.')
324
PRELIMINARY DISSERTATIONS.
would have seen the discovery of gunpowder,
which for ever guarded civilized society against
barbarians, while it transferred military strength
from the few to the many; of paper and print¬
ing, which rendered a second destruction of the
repositories of knowledge impossible, as well as
opened a way by which it was to he finally ac¬
cessible to all mankind; of the compass, by
means of which navigation had ascertained the
form of the planet, and laid open a new con¬
tinent more extensive than his world. If he
had turned to civil institutions, he might have
learned that some nations had preserved an
ancient, simple, and seemingly rude mode of
legal proceeding, which threw into the hands
of the majority of men a far larger share of
judicial power than was enjoyed by them in
any ancient democracy. He would have seen
everywhere the remains of that principle of
representation, the glory of the Teutonic race,
by which popular government, anciently im¬
prisoned in cities, became capable of being
strengthened by its extension over vast coun¬
tries, to which experience cannot even now
assign any limits; and which, in times still dis¬
tant, was to exhibit, in the newly-discovered
continent, a republican confederacy, likely to
surpass the Macedonian and Roman empires in
extent, greatness, and duration, but gloriously
founded on the equal rights, not like them on
the universal subjection, of mankind. In one
respect, indeed, he might have lamented that
the race of man had made a really retrograde
movement; that they had lost the liberty of
philosophizing; that the open exercise of their
highest faculties was interdicted. But he might
also have perceived that this giant evil had re¬
ceived a mortal wound from Luther, who in his
warfare against Rome had struck a blow against
all human authority, and unconsciously dis¬
closed to mankind that they were entitled, or
rather bound, to form and utter their own opin¬
ions, and most of all on the most deeply in¬
teresting subjects: for although this most fruit¬
ful of moral truths was not yet so released from
its combination with the wars and passions of
the age as to assume a distinct and visible form,
its action was already discoverable in the divisions
among the Reformers, and in the fears and
struggles of civil and ecclesiastical oppressors.
The Council of Trent, and the Courts of Paris,
Madrid, and Rome, had before that time fore¬
boded the emancipation of reason.
Though the middle age be chiefly memorable
as that in which the foundations of a new order
of society were laid, uniting the stability of the
oriental system, without its inflexibility, to the
activity of the Hellenic civilisation, without its
disorder and inconstancy, yet it is not unworthy
of notice, on account of the subterranean cur¬
rent which flows through it, from the speculations
of ancient to those of modern times. That dark
stream must be uncovered before the history of
the European understanding can be thoroughly
comprehended. It was lawful for the emancipa¬
tors of reason in their first struggles to carry on
mortal war against the Schoolmen. The neces¬
sity has long ceased; they are no longer danger¬
ous ; and it is now felt by philosophers that it is
time to explore and estimate that vast portion of
the history of philosophy from which we have
scornfully turned our eyes.1 A few sentences
only can be allotted to the subject in this place.
In the first moiety of the middle age, the dark¬
ness of Christendom was faintly broken by a few
thinly-scattered lights. Even then, Moses Ben
Maimon taught philosophy among the persecut¬
ed Hebrews, whose ancient schools had never
perhaps been wholly interrupted; and a series of
distinguished Mahometans, among whom two are
known to us by the names of Avicenna and
Averroes, translated the Peripatetic writings
into their own language, expounded their doc¬
trines in no servile spirit to their followers, and
1 Tenneman, Geschichte dcr Philosophies VIII. Band. 1811. Cousin, Cours de VHutoire dc la Philos, p. 20. Paris, 1828.
My esteem for this admirable writer encourages me to say, that the beauty of his diction has sometimes the same effect
on his thoughts that a sunny haze produces on outward objects; and to submit to his serious consideration, whether the
allurements of Schelling’s system have not betrayed him into a too frequent forgetfulness that principles, equally adapted
to all phenomena, furnish in speculation no possible test of their truth, and lead, in practice, to total indifference and inac¬
tivity respecting human affairs. I quote with pleasure an excellent observation from this work. “ Le moyen age n’est
pas autre chose que la formation penible, lente et sanglante, de tous les Siemens de la civilisation moderne; je dis la forma¬
tion, et non leur ddveloppement’' (P. 27.)
DISSERTATION SECOND.
325
enabled the European Christians to make those
versions of them from Arabic into Latin, which
in the eleventh and; twelfth centuries gave birth
to the scholastic philosophy.
The schoolmen were properly theologians, who
employed philosophy only to define and support
that system of Christian belief which they and
their contemporaries had embraced. The founder
of that theological system was Aurelius Augusti¬
nus, 1 (called by us Augustin) bishop of Hippo, in
the province of Africa; a man of great genius and
ardent character, who adopted at different periods
of his life the most various, but at all times the
most decisive and systematic, as well as daring
and extreme opinions. This extraordinary man
became, after some struggles, the chief Doctor,
and for ages almost the sole oracle of the Latin
church. It happened by a singular accident,
that the schoolmen of the twelfth century, who
adopted his theology, instead of borrowing their
defensive weapons from Plato, the favourite of
their master, had recourse for the exposition and
maintenance of their doctrines to the writings of
Aristotle, the least pious of philosophical theists.
The Augustinian doctrines of original sin, pre¬
destination, and grace, little known to the ear¬
lier Christian writers, who appear indeed to
have adopted opposite and milder opinions, were
espoused by Augustin himself in his old age;
when by a violent swing from his youthful
Mauicheism, which divided the sovereignty of
the world between two adverse beings, he did
not shrink, in his pious solicitude for tracing
the power of God in all events, from presenting
the most mysterious parts of the moral govern¬
ment of the universe, in their darkest colours
and their sternest shape, as articles of faith, the
objects of the habitual meditation and practical
assent of mankind. The principles of his rigor¬
ous system, though not with all their legitimate
consequences, were taught in the schools; re¬
spectfully promulgated rather than much incul¬
cated by the western church (for in the East
these opinions seem to have been unknown);
scarcely perhaps distinctly assented to by the
majority of the clergy; and seldom heard of by
laymen till the systematic genius and fervid
eloquence of Calvin rendered them a popular
creed in the most devout and moral portion of
the Christian world. Anselm,2 the Piedmontese
archbishop of Canterbury, was the earliest re¬
viver of the Augustinian opinions. Aquinas3
was their most redoubted champion. To them,
however, the latter joined others of a different
spirit. Faith, according to him, was a virtue,
not in the sense in which it denotes the things
believed, but in that in which it signifies the
state of mind which leads to right belief. Good¬
ness he regarded as the moving principle of the
Divine government; justice, as a modification
of goodness; and, with all his zeal to magnify
the sovereignty of God, he yet taught, that
though God always wills what is just, nothing
is j ust solely because he wills it. Scotus,4 the
most subtile of doctors, recoils from the Augus¬
tinian rigour, though he rather intimates than
avows his doubts. He was assailed for his ten¬
dency towards the Pelagian or Anti-Augusti-
nian doctrines by many opponents, of whom
the most famous in his time was Thomas Brad-
wardine,5 archbishop of Canterbury, formerly
confessor of Edward III., whose defence of pre¬
destination was among the most noted works of
that age. He revived the principles of the an¬
cient philosophers, who, from Plato to Marcus
Aurelius, taught that error of judgment, being
involuntary, is not the proper subject of moral
disapprobation; which indeed is implied in
Aquinas’s account of faith.6 But he appears to
have been the first whose language inclined to-
1 Notes and Illustrations, note B.
3 Died in 1109.
3 Born in 1224; died in 1279. Notes and Illustrations, note C.
4 Born about 1265 ; died at Cologne (where his grave is still shown) in 1308. Whether he was a native of Dunston
in Northumberland, or of Dunse in Berwickshire, or of Down in Ireland, was a question long and warmly contested, but
which seems to be settled by his biographer, Luke Wadding, who quotes a passage of Scotus’s Commentary on Aris¬
totle’s Metaphysics, where he illustrates his author thus : “ As in the definition of St Francis, or St Patrick, man is ne¬
cessarily presupposed.” (Scoti Opera, I. 3.) As Scotus was a Franciscan, the mention of St Patrick seems to show that
he was an Irishman. Notes and Illustrations, note D.
5 Born about 1290; died in 1349; the contemporary of Chaucer, and probably a fellow-student of Wicliffe and
Roger Bacon. His principal work was entitled, De Causa Dei contra Pelagium, et de Virtute Cans arum, Libri III-
e Notes and Illustrations, note £.
326
PRELIMINARY DISSERTATIONS.
wards that most pernicious of moral heresies,
which represents morality to be founded on will.1 2 3
William of Ockham, the most justly celebrated
of English schoolmen, went so far beyond this
inclination of his master, as to affirm, that “ if
God had commanded his creatures to hate him¬
self, the hatred of God would ever he the duty
of mana monstrous hyperbole, into which
he was perhaps betrayed by his denial of the
doctrine of general ideas, the pre-existence of
which in the Eternal intellect was commonly
regarded as the foundation of the immutable
nature of morality. The doctrine of Ockham,
which by necessary implication refuses moral
attributes to the Deity, and contradicts the ex¬
istence of a moral government, is practically
equivalent to atheism.8 As all devotional feel¬
ings have moral qualities for their sole object;
as no being can inspire love or reverence other¬
wise than by those qualities which are naturally
amiable or venerable, this doctrine would, if
men were consistent, extinguish piety, or, in
other words, annihilate religion. Yet so asto¬
nishing are the contradictions of human nature,
that this most impious of all opinions probably
originated in a pious solicitude to magnify the
sovereignty of God, and to exalt his authority
even above his own goodness. Hence we may
understand its adoption by John Gerson, the
oracle of ffie Council of Constance, and the
great opponent of the spiritual monarchy of the
Pope; a pious mystic, who placed religion in
devout feeling.5 In further explanation, it
may be added, that Gerson was of the sect
of the Nominalists, of which Ockham was the
founder; and that he was the more ready to fol¬
low his master, because they both courageously
maintained the independence of the state on the
church, and the authority of the church over
the Pope. The general opinion of the schools
was, however, that of Aquinas, who, from the
native soundness of his own understanding, as
well as from the excellent example of Aristotle,
was averse from all rash and extreme dogmas
on questions which had any relation, however
distant, to the duties of life.
It is very remarkable, though hitherto unob¬
served, that Aquinas anticipated those contro¬
versies respecting perfect disinterestedness in
the religious affections which occupied the most
illustrious members of his communion4 four
hundred years after his death; and that he dis¬
cussed the like question respecting the other
affections of human nature with a fulness and
clearness, an exactness of distinction, and a
justness of determination, scarcely surpassed
by the most acute of modern philosophers.5 It
ought to be added, that, according to the most
natural and reasonable construction of his words,
he allowed to the church a control only over
spiritual concerns, and recognised the supremacy
of the civil powers in all temporal affairs.6
It has already been stated that the scholastic
system was a collection of dialectical subtilties,
contrived for the support of the corrupted Chris¬
tianity of that age, by a succession of divines,
whose extraordinary powers of distinction and
reasoning were morbidly enlarged in the long
meditation of the cloister, by the exclusion of
every other pursuit, and the consequent palsy
of every other faculty; who were cut off from
all the materials on which the mind can operate,
and doomed for ever to toil in defence of what they
must never dare to examine ; to whom their age
and their condition denied the means of acquiring
literature, of observing nature, or of studying
mankind. The few in whom any portion of ima¬
gination and sensibility survived this discipline,
retired from the noise of debate, to the contem¬
plation of pure and beautiful visions. They
1 Notes and Illustrations, note F.
2 A passage to this effect, from Ockham, with nearly the same remark, has, since the text was written, been discovered
on a re-perusal of Cudworth’s Immutable Morality. See p. 10.
3 “ Ilemitto ad quod Occam de hac materia in Lib. Sentent. dicit, in qua explicatione si rudis judicetur, nescio quia ao-
pellabitur subtilitas.” (Gerson de Vita Spirit. Op. III. 14. Hag. Com. 1728.)
* Bossuet and Fenelon.
* See Aquinas, Comm, in Hi. Lib. Sentent. distinctio xxix. quaest. i. art. 3. “ Utrum Deus sit super omnia diligendus
ex charitate.” Art. 4. “ Utrum in dilectione Dei possit haberi respectus ad aliquam mercedem.” (Opera. IX. 322, 325.)
Some illustrations of this memorable anticipation, which has escaped the research even of the industrious Tenneman. will
be found in the Notes and Illustrations, note G.
6 Notes and Illustrations, note H.
DISSERTATION SECOND.
327
were called Mystics. The greater part, driven
back on themselves, had no better employment
than to weave cobwebs out of the terms of art
which they had vainly, though ingeniously, mul¬
tiplied. The institution of clerical celibacy,
originating in an enthusiastic pursuit of purity,
promoted by a mistake in moral prudence, which
aimed at raising religious teachers in the esteem
of their fellows, and at concentrating their whole
minds on professional duties, at last, encouraged
by the ambitious policy of the see of Rome, de¬
sirous of detaching them from all ties but her
own, had the effect of shutting up all the avenues
which Providence has opened for the entrance
of social affection and virtuous feeling into the
human heart. Though this institution perhaps
prevented knowledge from becoming once more
the exclusive inheritance of a sacerdotal caste;
though the rise of innumerable laymen, of the
lowest condition, to the highest dignities of the
church, was the grand democratical principle of
the middle age, and one of the most powerful
agents in impelling mankind towards a better
order; yet celibacy must be considered as one of
the peculiar infelicities of these secluded philo¬
sophers; not only as it abridged their happiness,
nor even solely, though chiefly, as it excluded
them from the school in which the heart is hu¬
manized, but also (an inferior consideration, but
more pertinent to our present purpose) because
the extinction of these moral feelings was as
much a subtraction from the moralist’s store of
facts and means of knowledge, as the loss of
sight or of touch could prove to those of the
naturalist.
Neither let it be thought that to have been
destitute of letters was to them no more than a
want of ornament and a curtailment of gratifi¬
cation. Every poem, every history, every ora¬
tion, every picture, every statue, is an experi¬
ment on human feeling, the grand object of
investigation by the moralist. Every work of
genius in every department of ingenious art and
polite literature, in proportion to the extent and
duration of its sway over the spirits of men, is
a repository of ethical facts, of which the moral
philosopher cannot be deprived by his own in¬
sensibility or by the iniquity of the times, with¬
out being robbed of the most precious instru¬
ments and invaluable materials of his science.
Moreover, letters, which are closer to human
feeling than science can ever be, have another
influence on the sentiments with which the
sciences are viewed, on the activity with which
they are pursued, on the safety with which they
are preserved, and even on the mode and spirit
in which they are cultivated: they are the
channels by which ethical science has a constant
intercourse with general feeling. As the arts
called useful maintain the popular honour of
physical knowledge, so polite letters allure the
world into the neighbourhood of the sciences of
mind and of morals. Whenever the agreeable
vehicles of literature do not convey their doc¬
trines to the public, they are liable to be inter¬
rupted by the dispersion of a handful of recluse
doctors, and the overthrow of their barren and
unlamented seminaries. Nor is this all: these
sciences themselves suffer as much when they
are thus released from the curb of common
sense and natural feeling, as the public loses by
the want of those aids to right practice which
moral knowledge in its sound state is qualified
to afford. The necessity of being intelligible at
least to all persons who join superior under¬
standing to habits of reflection, who are them¬
selves in constant communication with the far
wider circle of intelligent and judicious men,
which slowly but surely forms general opinion,
is the only effectual check on the natural prone¬
ness of metaphysical speculations to degenerate
into gaudy dreams or a mere war of words.
The disputants who are set free from the whole¬
some check of sense and feeling, generally carry
their dogmatism so far as to rouse the sceptic,
who from time to time is provoked to look into
the flimsiness of their cobwebs, and rushes in
with his besom to sweep them and their systems
into oblivion. It is true that literature, which
thus draws forth moral science from the schools
into the world, and recalls her from thorny dis¬
tinctions to her natural alliance with the intel¬
lect and sentiments of mankind, may, in ages
and nations otherwise situated, produce the
contrary evil of rendering Ethics shallow, decla¬
matory, and inconsistent. Europe at this mo¬
ment affords, in different countries, specimens
of these opposite and alike-mischievous extremes.
328
PRELIMINARY DISSERTATIONS
But we are now concerned only with the temp¬
tations and errors of the scholastic age.
We ought not so much to wonder at the mis¬
takes of men so situated, as that they, without
the restraints of the general understanding, and
with the clogs of system and establishment,
should in so many instances have opened ques¬
tions untouched by the more unfettered ancients,
and veins of speculation since mistakenly sup¬
posed to have been first explored in more mo¬
dern times. Scarcely any metaphysical contro¬
versy agitated among recent philosophers was
unknown to the schoolmen, unless we except
that which relates to liberty and necessity, which
would be an exception of doubtful propriety ;
for the disposition to it is clearly discoverable in
the disputes of the Thomists and Scotists re¬
specting the Augustinian and Pelagian doc¬
trines, 1 although restrained from the avowal of
legitimate consequences on either side by the
theological authority which both parties acknow¬
ledged. The Scotists steadily affirmed the blame¬
lessness of erroneous opinion; a principle which
is the only effectual security for conscientious
inquiry, for mutual kindness, and for public
quiet. The controversy between the Nominal¬
ists and Realists, treated by some modern wri¬
ters as an example of barbarous wrangling, was
in truth an anticipation of that modern dispute
which still divides metaphysicians, whether the
human mind can form general ideas, and whe¬
ther the words which are supposed to convey
such ideas he not general terms, representing
only a number of particular perceptions?—ques¬
tions so far from frivolous, that they deeply con¬
cern both the nature of reasoning and the struc¬
ture of language;—on which Hobbes, Berkeley,
Hume, Stewart, and Tooke, have followed the
Nominalists; and Descartes, Locke, Reid, and
Kant, have, with various modifications and some
inconsistencies, adopted the doctrine of the
Realists.2 3 With the schoolmen appears to have
originated the form, though not the substance,
of the celebrated maxim, which, whether true
or false, is pregnant with systems, <c There is
nothing in the understanding which was not be¬
fore in the senses.”5 Ockham4 the Nominalist
first denied the Peripatetic doctrine of the exist¬
ence of certain species (since the time of Des¬
cartes called ideas) as the direct objects of per¬
ception and thought, interposed between the
mind and outward objects; the modern oppo¬
sition to which by Dr Reid has been supposed
to justify the allotment of so high a station to
that respectable philosopher. He taught also
that we know nothing of mind hut its acts,
of which we are conscious. More inclination
towards an independent philosophy is to be
traced among the schoolmen than might he ex¬
pected from their circumstances. Those who
follow two guides will sometimes choose for
themselves, and may prefer the subordinate on
some occasions. Aristotle rivalled the church;
and the church herself safely allowed consider¬
able latitude to the philosophical reasonings of
those who were only heard or read in colleges
or cloisters, on condition that they neither im¬
pugned her authority, nor dissented from her
worship, nor departed from the language of her
creeds. The Nominalists were a freethinking
sect, who, notwithstanding their defence of
kings against the court of Rome, were perse¬
cuted by the civil power. It should not he for¬
gotten that Luther was a Nominalist.5
If not more remarkable, it is more pertinent
to our purpose, that the ethical system of the
schoolmen, or, to speak more properly, of Aqui¬
nas, as the moral master of Christendom for
three centuries, was in its practical part so ex¬
cellent as to leave little need of extensive change,
1 Notes and Illustrations, note I.
2 Locke speaks on this subject inconsistently ; Keid calls himself a Conceptualist; Kant uses terms so different that he
ought perhaps to be considered as of neither party. Leibnitz, varying in some measure from the general spirit of his specu¬
lations, warmly panegyrizes the Nominalists : “ Secta NominaUum, omnium inter scholasticos profundissima, et kodi-
ernse reformats philosophandi ration! congruentissima.” (Leibj*. Ojp. IY. Pars i. p. 59.)
3 Nil est in intellectu quod non prim fuit in sensu.
* “ Maximi vir ingenii, et eruditionis pro illo sevo summae, Wilhelmus Occam, Anglus.” (Leibn. ibid. p. 60.) The
writings of Ockham, which are very rare, I have never seen. I owe my knowledge of them to Tenneman, who however
quotes the words of Ockham, and of his disciple Biel.
5 “ In Martini Lutheri scriptis prioribus amor Nominalium satis elucet, donee in omnes monachos aequaliter affectus
esse ccepit.” (Leibx. IV. Pars i. p. 60.)
DISSERTATION SECOND.
329
with the inevitable exception of the connection
of his religious opinions with his precepts and
counsels. His rule of life is neither lax nor im¬
practicable. His grounds of duty are solely laid
in the nature of man, and in the wellbeing of
society. Such an intruder as subtilty seldom
strays into his moral instructions. With a most
imperfect knowledge of the Peripatetic writings,
he came near the great master, by abstaining,
in practical philosophy, from the unsuitable ex¬
ercise of that faculty of distinction, in which he
would probably have shown that he was little
inferior to Aristotle if he had been equally un¬
restrained. His very frequent coincidence with
modern moralists is doubtless to be ascribed
chiefly to the nature of the subject; but in part
also to that unbroken succession of teachers and
writers, which preserved the observations con¬
tained in what had been long the text-book of
the European schools, after the books themselves
had been for ages banished and forgotten. The
praises bestowed on Aquinas by every one of the
few great men who appear to have examined
his writings since the downfall of his power,
among whom may be mentioned Erasmus, Gro-
tius and Leibnitz, are chiefly, though not sole¬
ly, referable to his ethical works.1
Though the schoolmen had thus anticipated
many modern controversies of a properly meta¬
physical sort, they left untouched most of those
questions of ethical theory which were unknown
to, or neglected by the ancients. They do not
appear to have discriminated between the nature
of moral sentiments, and the criterion of moral
acts; to have considered to what faculty of our
mind moral approbation is referable; or to have
inquired whether our moral faculty, whatever it
may be, is implanted or acquired. Those who
measure only by palpable results, have very
consistently regarded the metaphysical and theo¬
logical controversies of the schools as a mere
waste of intellectual power. '■But the contem¬
plation of the athletic vigour and versatile skill
manifested by the European understanding, at
the moment when it emerged from this tedious
and rugged discipline, leads, if not to approba¬
tion, yet to more qualified censure. What
might have been the result of a different combi¬
nation of circumstances, is an inquiry which,
on a large scale, is beyond human power. We
may however venture to say, that no abstract
science, unconnected with religion, was likely
to be respected in a barbarous age ; and we may
be allowed to doubt whether any knowledge,
dependent directly on experience, and appli¬
cable to immediate practice, would have so
trained the European mind as to qualify it for
that series of inventions, and discoveries, and
institutions, which begins with the sixteenth
century, and of which no end can now be fore¬
seen but the extinction of the race of man.
The fifteenth century was occupied by the
disputes of the Realists with the Nominalists,
in which the scholastic doctrine expired. After
its close no schoolman of note appeared. The
sixteenth may be considered as the age of tran¬
sition from the scholastic to the modern philo¬
sophy. The former, indeed, retained posses¬
sion of the Universities, and was long after dis¬
tinguished by all the ensigns of authority. But
the mines were already prepared. The revolu¬
tion in opinion had commenced. The moral
writings of the preceding times had generally
been commentaries on that part of the Summa
Theologies of Aquinas which relates to Ethics.
Though these still continued to be published,
yet the most remarkable moralists of the six¬
teenth century indicated the approach of other
modes of thinking, by the adoption of the more
independent titles of Treatises on Justice and
Law. These titles were suggested, and the
spirit, contents, and style of the writings them¬
selves, were materially affected by the improved
cultivation of the Roman law, by the renewed
study of ancient literature, and by the revival
of various systems of Greek philosophy, now
studied in the original, which at once mitigated
and rivalled the scholastic doctors, and while
they rendered philosophy more free, re-opened its
communications with society and affairs. The
speculative theology which had arisen under
the French governments of Paris and London
2 T
DISS. II.
1 See especially the excellent Preface of Leibnitz to Nizolius, sect. 37.
330
PRELIMINARY DISSERTATIONS.
in the twelfth century, which flourished in the
thirteenth in Italy in the hands of Aquinas,
which was advanced in the British islands by
Scotus and Ockham in the fourteenth, was, in
the sixteenth, with unabated acuteness, hut with
a clearness and elegance unknown before the
restoration of letters, cultivated hy Spain, in
that age the most powerful and magnificent of
the European nations.
Many of these writers treated the law of war
and the practice of hostilities in a juridical form.1
Francis Victoria, who began to teach at Valla¬
dolid in 1525, is said to have first expounded
the doctrines of the schools in the language of
the age of Leo the Tenth. Dominic Soto,2 * a Do¬
minican, the confessor of Charles V., and the
oracle of the Council of Trent, to whom that
assembly were indebted for much of the preci¬
sion and even elegance for which their doctrinal
decrees are not unjustly commended, dedicated
his treatise on Justice and Law to Don Car¬
los ; in terms of praise which, used hy a writer
who is said to have declined the high dignities
of the church, lead us to hope that he was un¬
acquainted with the brutish vices of that wretch¬
ed prince. It is a concise and not inelegant
compound of the scholastic Ethics, which con¬
tinued to be of considerable authority for more
than a century.5 Both he and his master Vic¬
toria deserve to be had in everlasting remem-
tyance, for the part which they took on behalt
of the natives of America and of Africa, against
the rapacity and cruelty of the Spaniards. Vic¬
toria pronounced war against the Americans for
their vices or for their paganism to be unjust.4
Soto was the authority chiefly consulted by
Charles V., on occasion of the conference held
before him at Valladolid, in 1542, between Se¬
pulveda, an advocate of the Spanish colonists,
and Las Casas, the champion of the unhappy
Americans ; of which the result was a very im¬
perfect edict of reformation in 1543, which,
though it contained little more than a recogni¬
tion of the principle of justice, almost excited a
rebellion in Mexico. Sepulveda, a scholar and
a reasoner, advanced many maxims which were
specious, and in themselves reasonable, but
which practically tended to defeat even the
scanty and almost illusive reform which en¬
sued. Las Casas was a passionate missionary,
whose zeal, kindled by the long and near con¬
templation of cruelty, prompted him to exagge¬
rations of fact and argument;5 yet, with all its
errors, it afforded the only hope of preserving the
natives of America from extirpation. The opin¬
ion of Soto could not fail to be conformable to
his excellent principle, that “ there can be no
difference between Christians and Pagans, for
the law of nations is equal to all nations.”6 To
Soto belongs the signal honour of being the first
writer who condemned the African slave-trade.
“ It is affirmed,” says he, “ that the unhappy
Ethiopians are by fraud or force carried away
and sold as slaves. If this is true, neither those
who have taken them, nor those who purchased
them, nor those who hold them in bondage, can
ever have a quiet conscience till they emancipate
them, even if no compensation should be ob¬
tained.”7 As the work which contains this
memorable condemnation of man-stealing and
slavery was the substance of lectures many years
delivered at Salamanca, philosophy and religion
1 Many of the separate dissertations, on points of this nature, are contained in the immense collection entitled Trac/afia
Tractatuum, published at Venice in 1584, under the patronage of the Roman see. There are three de Bello; one by Lupus
of Segovia when Francis I. was prisoner in Spain ; another, more celebrated, by b rancis Arias, who, on the 11th June 1532,
discussed before the College of Cardinals the legitimacy of a war by the Emperor against the Pope. There are two e
Pace; and others de Potestate Regia, de Poena Mortis, &c. The most ancient and scholastic is that ol J. de Eignano ot Milan cte
Bello. The above writers are mentioned in the Prolegomena to Grotius de Jure Belli. Pietro Belloni (Counsellor of the
Duke of Savoy) de Re Militari, treats his subject with the minuteness of a Judge-Advocate, and has more modern examples,
chiefly Italian, than Grotius. . . „ ^ , , , , ,
2 Born in 1494; died in 1560. (Aniown Bibliotheca Hispana Nova.) The opinion of Sotos knowledge entertameri
by his contemporaries is expressed in a jingle, Qni scit Sotumscit totum.
' * Notes and Illustrations, note K. _ „ xu j c
4 “ Indis non debere auferri imperium, ideo quia sunt peccatores, vel ideo quia non sunt Christiani, were the words ot
Victoria.
5 Notes and Illustrations, note L. »
6 “ Neque discrepantia (ut reor) est inter Christianos et infideles, quoniam ius gentium cunctis gentibus aequa.e est-
2 Soto de Justitia et Jure, lib. iv. quaest. ii. art. 2.
DISSERTATION SECOND.
331
appear, by the hand of their faithful minister,
to have thus smitten the monsters in their earliest
infancy. It is hard for any man of the present
age to conceive the praise which is due to the
excellent monks who courageously asserted the
rights of those whom they never saw, against
the prejudices of their order, the supposed inte¬
rest of their religion, the ambition of their go¬
vernment, the avarice and pride of their coun¬
trymen, and the prevalent opinions of their time.
Francis Suarez,1 2 3 a Jesuit, whose voluminous
works amount to twenty-four volumes in folio,
closes the list of writers of his class. His
work on Laws, and on God the Lawgiver, may
be added to the above treatise of Soto, as ex¬
hibiting the most accessible and perspicuous
abridgement of the theological philosophy in its
latest form.
Grotius, who, though he was the most upright
and candid of men, could not have praised a
Spanish Jesuit beyond his deserts, calls Suarez
the most acute of philosophers and divines.*
On a practical matter, which may be naturally
mentioned here, though in strict method it
belongs to another subject, the merit of Suarez
is conspicuous. He first saw that interna¬
tional law was composed not only of the simple
principles of justice applied to the intercourse
between states, but of those usages, long ob¬
served in that intercourse by the European
race, which have since been more exactly dis¬
tinguished as the consuetudinary law acknow¬
ledged by the Christian nations of Europe and
America.5 On this important point his views
are more clear than those of his contemporary
Alberico Gentili.4 It must even be owned,
that the succeeding intimation of the same
general doctrine by Grotius is somewhat more
dark, perhaps from his excessive pursuit of con¬
cise diction.5
SECTION IV.
Modern Ethics.
The introduction to the great work of Gro¬
tius, 6 composed in the first years of his exile, and
published at Paris in 1625, contains the most
clear and authentic statement of the general
principles of morals prevalent in Christendom
after the close of the schools, and before the
writings of Hobbes had given rise to those ethi¬
cal controversies which more peculiarly belong
to modern times. That he may lay down the
fundamental principles of Ethics, he introduces
Carneades on the stage as denying altogether
the reality of moral distinctions; teaching that
law and morality are contrived by powerful men
for their own interest; that they vary in differ¬
ent countries, and change in successive ages;
that there can be no natural law, since nature
leads men as well as other animals to prefer
their own interest to every other object; that
therefore there is either no justice, or if there
be, it is another name for the height of folly,
1 Born in 1538; died in 1617-
2 “ Tantse subtilitatis philosophum et theologum, ut vix quemquam habeat parent.” (Grotii Epist. apud Anton. Bibl.
Hup. Nova.)
3 “ Nunquam enim civitates sunt sibi tam sufficientes quin indigeant niutuo juvamine et societate, interdum ad majo-
rem utilitatem, interdum ob necessitatem moralem. Hac igitur ratione indigent aliquo jure quo dirigantur et recte ordi-
nentur in hoc genere societatis. Et quamvis magua ex parte hoc fiat per rationem naturalem, non tamen sufficienter et
immediate quoad omnia, ideoque specialia jura poterant usu earundem gentium introduci." (Suarez de Legibus, lib. ii. cap. ii.
9. et seq.)
* Born in the March of Ancona in 1550; died at London in 1608.
5 Grotius de Jure Belli, lib. i. cap. i. sect. 14.
6 Prolegomena. His letter to Vossius, of 1st August 1625, determines the exact period of the publication of this famous
work. Grotii Epist. 74.
332
preliminary dissertations.
inasmuch as it is a fond attempt to persuade a
human being to injure himself for the unnatural
purpose of benefiting his fellow-men.1 2 3
To this Grotius answered, that even inferior
animals, under the powerful though transient
impulse of parental love, prefer their young to
their own safety or life; that gleams of com¬
passion, and, he might have added, of gratitude
and indignation, appear in the human infant
long before the age of moral discipline; that
man at the period of maturity is a social animal,
who delights in the society of his fellow-crea¬
tures for its own sake, independently of the help
and accommodation which it yields ; that he is
a reasonable being, capable of framing and pur¬
suing general rules of conduct, of which he
discerns that the observance contributes to a
regular, quiet, and happy intercourse between
all the members of the community; and that
from these considerations all the precepts of mo¬
rality, and all the commands and prohibitions of
just law, may be derived by impartial reason.
“ And these principles,” says the pious philoso¬
pher, “ would have their weight, even if it were
to he granted (which could not he conceded
without the highest impiety) that there is no
God, or that he exercises no moral government
over human affairs.” * “ Natural law is the dic¬
tate of right reason, pronouncing that there is in
some actions a moral obligation, and in oth ex¬
actions a moral deformity, arising from their re¬
spective suitableness or repugnance to the reason¬
able and social nature; and that consequently
such acts are either forbidden or enjoined by God,
the author of nature. Actions which are the
subject of this exertion of reason, are in them¬
selves lawful or unlawful, and are therefore as
such necessarily commanded or prohibited by
God.”
Such was the state of opinion respecting the
first principles of the moral sciences, when, after
an imprisonment of a thousand years in the
cloister, they began once more to hold inter¬
course with the general understanding of man¬
kind. It will be seen in the laxity and confu¬
sion, as well as in the prudence and pui'ity of
this exposition, that some part of the method
and pi-ecision of the schools was lost with their
endless subtilties and their barbarous language.
It is manifest that the latter paragraph is a pro¬
position, not what it affects to be, a definition;
that as a proposition it contains too many terms
very necessary to be defined; that the purpose
of the excellent writer is not so much to lay
down a first principle of morals, as to exert his
unmatched power of saying much in few words,
in order to assemble within the smallest compass
the most weighty inducements, and the most
effectual persuasions to welldoing.
This was the condition in which ethical theory
was found by Hobbes, with whom the present
Dissertation should have commenced, if it had
been possible to state modem controversies in a
satisfactory manner, without a retrospect of
the revolutions in opinion from which they in
some measure flowed.
HOBBES.5
Thomas Hobbes of Malmesbury may be num- a new character to European philosophy in the
bered among those eminent persons born in the succeeding age.4 He was one of the late wi’i-
latter half of the sixteenth century, who gave ters and late learners. It was not till he was
1 The same commonplace paradoxes were retailed by the Sophists, whom Socrates is introduced as chastising in the Dia¬
logues of Plato. They were common enough to be put by the historian into the mouth of an ambassador in a public speech.
AvS«/ rvpawif n a'uXs/ ot^riv i%ov<ry oahtv a.Xo'yov o 71 (THUCYD. vi. 85.)
2 “ Et nsec quidem locum aliquem haberent, etiamsi daretur (quod sine summo scelere dari nequit) non esse Deum, aut
non curari ab eo negotia humana.” {Proleg. 11.) And in another place, “ Jus naturaleest dictatum rectse rationis, indicans
actui alicui, ex ejus convenientia aut disconvenientia cum ipsa natura rational! et social!, inesse moralem turpitudinem aut
necessitatem moralem, ac eonsequenter ab auctore naturae Deo talem actum aut vetari aut praecipi. Actus de quibus tale exstat
dictatum, debit! sunt aut illiciti per se, atque ideo a Deo necessario praecepti aut vetiti intelliguntur.” (lab. i. cap. i. sect. 10.)
3 Born in 1588; died in 1670.
4 Bacon, Descartes, Hobbes, and Grotius. The writings of the first are still as delightful and wonderful as they ever
were, and his authority will have no end. Descartes forms an era in the history of Metaphysics, of Physics, of Mathema¬
tics. The controversies excited by Grotius have long ceased, but the powerful influence of his works will be doubted by
those only who are unacquainted with the disputes of the seventeenth century.
DISSERTATION SECOND.
333
nearly thirty that he supplied the defects of his
early education, by classical studies so successfully
prosecuted, that he wrote well in the Latin then
used by his scientific contemporaries; and made
such proficiency in Greek as, in his earliest work,
the Translation of Thucydides, published when
he was forty, to afford a specimen of a version still
valued for its remarkable fidelity; though written
with a stiffness and constraint very opposite to
the masterly facility of his original compositions.
It was after forty that he learned the first rudi¬
ments of geometry (so miserably defective was
his education); but yielding to the paradoxical
disposition apt to infect those who begin to learn
after the natural age of commencement, he ex¬
posed himself, by absurd controversies with the
masters of a science which looks down with
scorn on the Sophist. A considerable portion
of his mature age was passed on the Continent,
where he travelled as tutor to two successive
Earls of Devonshire; a family with whom he
seems to have passed near half a century of his
long life. In France his reputation, founded at
that time solely on personal intercourse, became
so great, that his observations on the Meditations
of Descartes were published in the works of that
philosopher, together with those of Gassendi
and Arnauld.1 It was about his sixtieth year
that he began to publish those philosophical
writings which contain his peculiar opinions;—
which set the understanding of Europe into ge¬
neral motion, and stirred up controversies among
metaphysicians and moralists, not even yet de¬
termined. At the age of eighty-seven he had
the boldness to publish metrical versions of the
Iliad and Odyssey, which the greatness of his
name, and the singularity of the undertaking,
still render objects of curiosity, if not of criti¬
cism. He owed his influence to various causes;
at the head of which may be placed that genius
for system, which, though it cramps the growth
of knowledge,2 perhaps finally atones for that
mischief, by the zeal and activity which it rouses
among followers and opponents, who discover
truth by accident, when in pursuit of weapons
for their warfare. A system which attempts a
task so hard as that of subjecting vast provinces
of human knowledge to one or two principles,
if it presents some striking instances of con¬
formity to superficial appearances, is sure to
delight the framer; and, for a time, to subdue
and captivate the student too entirely for sober
reflection and rigorous examination. The evil
does not indeed very frequently recur. Perhaps
Aristotle, Hobbes, and Kant, are the only per¬
sons who united in the highest degree the great
faculties of comprehension and discrimination
which compose the Genius of System. Of the
three, Aristotle alone could throw it off where
it was glaringly unsuitable ; and it is deserving
of observation, that the reign of system seems,
from these examples, progressively to shorten in
proportion as reason is cultivated and knowledge
advances. But, in the first instance, consist¬
ency passes for truth. When principles in some
instances have proved sufficient to give an un¬
expected explanation of facts, the delighted
reader is content to accept as true all other de¬
ductions from the principles. Specious pre¬
mises being assumed to be true, nothing more
can be required than logical inference. Mathe¬
matical forms pass current as the equivalent of
mathematical certainty. The unwary admirer
is satisfied with the completeness and symmetry
of the plan of his house—unmindful of the need
of examining the firmness of the foundation and
the soundness of the materials. The system-
maker, like the conqueror, long dazzles and
overawes the world; but when their sway is past,
the vulgar herd, unable to measure their aston¬
ishing faculties, take revenge by trampling on
fallen greatness.
The dogmatism of Hobbes was, however un¬
justly, one of the sources of his fame. The
founders of systems deliver their novelties with
the undoubting spirit of discoverers; and their
1 The prevalence of freethinking under Louis XIII., to a far greater degree than it was avowed, appears not on v rom
the complaints of Mersenne and of Grotius, but from the disclosures of Guy Patin; who, in his Letters, describes is ow
conversations with Gassendi and Naude, so as to leave no doubt of their opinions. _
2 “ Another error,” says the Master of Wisdom, “ is the over-early and peremptory reduction or knowle ge ^ 0
and methods, from which time commonly receives small augmentation.” (Bacon’s Advancement of Learning,^ °5’ , v
u Method,” says he, “ carrying a show of total and perfect knowledge, has a tendency to generate acquiescence,
pregnant words!
334
preliminary dissertations.
followers are apt to be dogmatical, because they
can see nothing beyond their own ground. It
might seem incredible, if it were not established
by the experience of all ages, that those who
differ most from the opinions of their fellow-
men are most confident of the truth of their
own. But it commonly requires an overween¬
ing conceit of the superiority of a man’s own
judgment, to make him espouse very singular
notions; and when he has once embraced them,
they are endeared to him by the hostility of
those whom he contemns as the prejudiced vul¬
gar. The temper of Hobbes must have been
originally haughty. The advanced age at which
he published his obnoxious opinions, rendered
him more impatient of the acrimonious opposi¬
tion which they necessarily provoked; until at
length a strong sense of the injustice of the
punishment impending over his head, for the
publication of what he believed to be truth, co¬
operated with the peevishness and timidity of
his years, to render him the most imperious and
morose of dogmatists. His dogmatism has in¬
deed one quality more offensive than that of
most others. Propositions the most adverse
to the opinions of mankind, and the most ab¬
horrent from their feelings, are introduced into
the course of his argument with mathematical
coldness. He presents them as demonstrated
conclusions, without deigning to explain to his
fellow-creatures how they all happened to be¬
lieve the opposite absurdities; without even the
compliment of once observing how widely his
discoveries were at variance with the most an¬
cient and universal judgments of the human
understanding. The same quality in Spinoza
indicates a recluse’s ignorance of the world.
In Hobbes it is the arrogance of a man who
knows mankind and despises them.
A permanent foundation of his fame consists in
his admirable style, which seems to be the very
perfection of didactic language. Short, clear, pre¬
cise, pithy, his language never has more than one
meaning, which never requires a second thought
to find. By the help of his exact method, it
takes so firm a hold on the mind, that it will
not allow attention to slacken. His little tract
on Human Nature has scarcely an ambiguous or
a needless word. He has so great a power of
always choosing the most significant term, that
he never is reduced to the poor expedient of
using many in its stead. He had so thoroughly
studied the genius of the language, and knew
so well to steer between pedantry and vulgarity,
that two centuries have not superannuated prob¬
ably more than a dozen of his words. His ex¬
pressions are so luminous, that he is clear with¬
out the help of illustration. Perhaps no writer
of any age or nation, on subjects so abstruse,
has manifested an equal power of engraving his
thoughts on the mind of his readers. He seems
never to have taken a word for ornament or
pleasure; and he deals with eloquence and
poetry as the natural philosopher who explains
the mechanism of children’s toys, or deigns to
contrive them. Yet his style so stimulates at¬
tention, that it never tires; and, to those who
are acquainted with the subject, appears to have
as much spirit as can be safely blended with
reason. He compresses his thoughts so un¬
affectedly, and yet so tersely, as to produce oc¬
casionally maxims which excite the same agree¬
able surprise with wit, and have become a sort
of philosophical proverbs; the success of which
he partly owed to the suitableness of such forms
of expression to his dictatorial nature. His
words have such an appearance of springing
from his thoughts, as to impress on the reader
a strong opinion of his originality, and indeed
to prove that he was not conscious of borrow¬
ing; though conversation with Gassendi must
have influenced his mind; and it is hard to be¬
lieve that his coincidence with Ockham should
have been purely accidental, on points so im¬
portant as the denial of general ideas, the refer¬
ence of moral distinctions to superior power,
and the absolute thraldom of religion under the
civil power, which he seems to have thought ne¬
cessary, to maintain that independence of the
state on the church with which Ockham had
been contented.
His philosophical writings might be read with¬
out reminding any one that the author was more
than an intellectual machine. They never be¬
tray a feeling except that insupportable arro¬
gance which looks down on men as a lower
species of beings; whose almost unanimous hos¬
tility is so far from shaking the firmness of his
DISSERTATION SECOND.
335
conviction, or even ruffling the calmness of his
contempt, that it appears too petty a circum¬
stance to require explanation, or even to merit
notice. Let it not he forgotten, that part of his
renown depends on the application of his ad¬
mirable powers to expound truth when he meets
it. This great merit is conspicuous in that part
of his treatise of Human Nature which relates
to the percipient and reasoning faculties. It is
also very remarkable in many of his secondary
principles on the subject of government and law,
which, while the first principles are false and
dangerous, are as admirable for truth as for his
accustomed and unrivalled propriety of expres¬
sion.1 2 3 In many of these observations he even
shows a disposition to soften his paradoxes, and
to conform to the common sense of mankind.®
It was with perfect truth observed by my
excellent friend Mr Stewart, that “ the ethical
principles of Hobbes are completely interwoven
with his political system.”* He might have
said, that the whole of Hobbes’s system, moral,
religious, and in part philosophical, depended on
his political scheme; not indeed logically, as con¬
clusions depend on premises, but (if the word
may be excused) psychologically, as the formation
of one opinion may be influenced by a disposi¬
tion to adapt it to previously cherished opinions.
The Translation of Thucydides, as he himself
boasts, was published to show the evils of popu¬
lar government.4 Men he represented as being
originally equal, and having an equal right to all
things, but as being taught by reason to sacri¬
fice this right for the advantages of peace, and
to submit to a common authority, which can
preserve quiet, only by being the sole depositary
of force, and must therefore be absolute and un¬
limited. The supreme authority cannot he suf¬
ficient for its purpose, unless it he wielded by a
single hand ; nor even then, unless his absolute
power extends over religion, which may prompt
men to discord by the fear of an evil greater
than death. The perfect state of a community,
according to him, is where law prescribes the
religion and morality of the people, and where
the will of an absolute sovereign is the sole foun¬
tain of law. Hooker had inculcated the simple
truth, that <c to live by one man’s will is the
cause of many men’s misery.” Hobbes em¬
braced the daring paradox, that to live by one
man’s will is the only means of all men’s happi¬
ness. Having thus rendered religion the slave
of every human tyrant, it was an unavoidable
consequence, that he should he disposed to lower
her character, and lessen her power over men ;
that he should regard atheism as the most effec¬
tual instrument of preventing rebellion; at least
that species of rebellion which prevailed in his
time, and had excited his alarms. The formi¬
dable alliance of religion with liberty haunted
his mind, and urged him to the bold attempt of
rooting out both these mighty principles; which,
when combined with interests and passions,
when debased by impure support, and provoked
by unjust resistance, have indeed the power of
fearfully agitating society; but which are, never¬
theless, in their own nature, and as far as they
are unmixed and undisturbed, the fountains of
justice, of order, of peace, as well as of those
moral hopes, and of those glorious aspirations
after higher excellence, which encourage and
exalt the soul in its passage through misery and
depravity. A Hohbist is the only consistent
persecutor; for he alone considers himself as
bound, by whatever conscience he has remain¬
ing, to conform to the religion of the sovereign.
1 See Be Corpore Politico, Part i. chap. ii. iii. iv. and Leviathan, Part i. chap. xiv. xv. for remarks of this sort, full of
sagacity.
2 “ The laws of nature are immutable and eternal; for injustice, ingratitude, arrogance, pride, iniquity, acception of per¬
sons, and the rest, can never be made lawful. For it can never be that war shall preserve life, and peace destroy it.”
{Leviathan, Part i. chap. xv. See also Part ii. chap. xxvi. xxviii. on Laws, and on Punishments.)
3 See Dissertation First, p. 42. The political state of England is indeed said by himself to have occasioned his first
philosophical publication.
Nascitur interea scelus execrabile belli.
 Horreo spectans,
Meque ad dilectam confero Lutetiam,
Postque duos annos edo De Give Libellum. {Vita Hobbesii.)
4 The speech of Euphemus in the 6th book of that historian, and the conference between the ministers from Athens and
the Melean chiefs, in the 5th book, exhibit an undisguised HobUsm, which was very dramatically put into the mouth of
Athenian statesmen at a time when, as we learn from Plato and Aristophanes, it was preached by the Sophists.
336
PRELIMINARY DISSERTATIONS.
He claims from others no more than he is him¬
self ready to yield to any master;1 while the
religionist who persecutes a member of another
communion, exacts the sacrifice of conscience
and sincerity, though professing that, rather than
make it himself, he is prepared to die.
REMARKS.
The fundamental errors on which the ethical
system of Hobbes is built are not peculiar to
him; though he has stated them with a holder
precision, and placed them in a more conspicu¬
ous station in the van of his main force, than
any other of those who have either frankly
avowed or tacitly assumed them, from the be¬
ginning of speculation to the present moment.
They may be shortly stated as follows.
1. The first and most inveterate of these er¬
rors is, that he does not distinguish thought from
feeling, or rather that he in express words con¬
founds them. The mere perception of an object,
according to him, differs from the pleasure or
pain which that perception may occasion, no
otherwise than as they affect different organs of
the bodily frame. The action of the mind in
perceiving or conceiving an object is precisely
the same with that of feeling the agreeable or
disagreeable.2 The necessary result of this ori¬
ginal confusion is, to extend the laws of the in¬
tellectual part of our nature over that other part
of it, hitherto without any adequate name, which
feels, and desires, and loves, and hopes, and
wills. In consequence of this long confusion,
or want of distinction, it has happened that,
while the simplest act of the merely intellectual
part has many names, (such as sensation, per¬
ception, impression, &c.) the correspondent act
of the other not less important portion of man
is not denoted by a technical term in philoso¬
phical systems; nor by a convenient word in
common language. Sensation has another more
common sense. Emotion is too warm for a ge¬
neric term. Feeling has some degree of the same
fault, besides its liability to confusion with the
sense of touch. Pleasure and pain represent only
two properties of this act, which render its re¬
petition the object of desire or aversion; which
last states of mind presuppose the act. Of these
words, emotion seems to be the least objec¬
tionable, since it has no absolute double mean¬
ing, and does not require so much vigilance in
the choice of the accompanying words as would
be necessary if we were to prefer feeling;
which, however, being a more familiar word,
may, with due caution, be also sometimes em¬
ployed. Every man who attends to the state
of his own mind will acknowledge, that these
words, emotion and feeling, thus used, are perfect¬
ly simple, and as incapable of further explana¬
tion by words as sight or hearing; which may
indeed be rendered into synonymous words, but
never can be defined by any more simple or
more clear. Reflection will in like manner teach
that perception, reasoning, and judgment may
be conceived to exist without being followed by
emotion. Some men hear music without gratifi¬
cation : one may distinguish a taste without being
pleased or displeased by it; or at least the relish
or disrelish is often so slight, without lessening
the distinctness of the sapid qualities, that the
distinction of it from the perception cannot be
doubted.
1 Spinoza adopted precisely the same first principle with Hobbes, that all men have a natural right, t,o all things.
(Tractatus Politicus, cap. ii. sect. 3.) He even avows the absurd and detestable maxim, that states are not bound to observe
their treaties longer than the interest or danger which first formed the treaties continues. But on the internal constitu¬
tion of states he embraces opposite opinions. Servitutis enim non pads interest omnem potestatem ad unum ti ansferre. (Ibid.
cap. vi. sect. 4.) Limited monarchy he considers as the only tolerable example of that species of government. An aristo¬
cracy nearly approaching to the Dutch system during the suspension of the Stadtholdership, he seems to prefer. He speaks
favourably of democracy, but the chapter on that subject is left unfinished. ‘‘ Nulla plane templa urbium sumptibus sedin-
canda, nec jura de opinionibus statuenda.” He was the first republican atheist of modern times, and probably the earhest
irreligious opponent of an ecclesiastical establishment. _ _ .
* This doctrine is explained in his tract on Human Nature, c. vii.—x. “ Conception is a motion in some internal substance
of the head, which proceeding to the heart, when it helpeth the motion there, it is caW.e&. pleasure ; when it weakeneth or
hindereth the motion, it is called pain." The same matter is handled more cursorily, agreeably to the practical purpose
of the work, in Leviathan, Part i. chap. vi. These passages are here referred to as proofs of the statement in the text.
With the materialism of it we have here no concern. If the multiplied suppositions were granted, we should not advance
one step towards understanding what they profess to explain. The first four words are as unmeaning as if one were to
say that greenness is very loud. It is obvious that many motions which promote the motion of the heart are extremely
painful.
DISSERTATION SECOND.
337
The multiplicity of errors which have flowed
into Moral Science from this original confusion
is very great. They have spread over many
schools of philosophy; and many of them are
prevalent to this daj. Hence the laws of the
understanding have been applied to the affec¬
tions; virtuous feelings have been considered
as just reasonings; evil passions represented as
mistaken judgments; and it has been laid down
as a principle, that the will always follows the
last decision of the practical intellect.1
2. By this great error, Hobbes was led to re¬
present all the variety of the desires of men, as
being only so many instances of objects delibe¬
rately and solely pursued; because they were the
means, and at the time perceived to be so, of
directly or indirectly procuring organic gratifi¬
cation to the individual.2 The human passions
are described as if they reasoned accurately, de¬
liberated coolly, and calculated exactly. It is
assumed that, in performing these operations,
there is and can be no act of life in which a man
does not bring distinctly before his eyes the
pleasure which is to accrue to himself from the
act. From this single and simple principle, all
human conduct may, according to him, be ex¬
plained and even foretold.
The true laws of this part of our nature (so
totally different from those of the percipient
part) were, by this grand mistake, entirely with¬
drawn from notice. Simple as the observation
is, it seems to have escaped not only Hobbes,
but many, perhaps most philosophers, that our
desires seek a great diversity of objects; that
the attainment of these objects is indeed follow¬
ed by, or rather called Pleasure; but that it
could not be so, if the objects had not been pre¬
viously desired. Many besides him have really
represented self as the ultimate object of every
action; but none ever so hardily thrust forward
the selfish system in its harshest and coarsest
shape. The mastery which he shows over other
metaphysical subjects, forsakes him on this. He
does not scruple, for the sake of this system, to
distort facts of which all men are conscious;
and to do violence to the language in which the
result of their uniform experience is conveyed.
“ Acknowledgment of power is called Honour.”3
His explanations are frequently sufficient con¬
futations of the doctrine which required them.
“ Pity is the imagination of future calamity to
ourselves, proceeding from the sense (observa¬
tion) of another man’s calamity.” “ Laughter
is occasioned by sudden glory in our eminence,
or in comparison with the infirmity of others.”
Every man who ever wept or laughed, may de¬
termine whether this be a true account of the
state of his mind on either occasion. “ Love is
a conception of his need of the one person de¬
sired;” a definition of love, which, as it ex¬
cludes kindness, might perfectly well compre¬
hend the hunger of a cannibal, provided that
it were not too ravenous to exclude choice.
“ Good-will, or charity, which containeth the na¬
tural affection of parents to their children, consists
in a man’s conception that he is able not only to
accomplish his own desires, but to assist other
men in theirsfrom which it follows, as the
pride of power is felt in destroying as well as in
saving men, that cruelty and kindness are the
same passion.4
Such were the expedients to which a man of
the highest class of understanding was driven,
in order to evade the admission of the simple
and evident truth, that there are in our nature
perfectly disinterested passions, which seek the
wellbeing of others as their object and end,
without looking beyond it to self, or pleasure,
or happiness. A proposition, from which such
a man could attempt to escape only by such
means, may be strongly presumed to be true.
3. Hobbes having thus struck the affections
out of his map of human nature, and having to¬
tally misunderstood (as will appear in a suc¬
ceeding part of this Dissertation) the nature even
of the appetites, it is no wonder that we should
1 “ Voluntas semper sequitur ultimum indicium intellectus practici.”
2 See the passages before quoted.
3 Human Nature, chap. viii. The ridiculous explanation of the admiration of personal beauty, “ as a sign of power ge¬
nerative,” shows the difficulties to which this extraordinary man was reduced by a false system. _ ?
4 Ibid. chap. ix. I forbear to quote the passage on Platonic love, which immediately follows. But, considering Hobbes s
blameless and honourable character, that passage is perhaps the most remarkable instance of the shifts to which his selfish
system reduced him.
DISS. II. 2 U
338
PRELIMINARY DISSERTATIONS.
find in it not a trace of the moral sentiments.
Moral good1 he considers merely as consisting
in the signs of a power to produce pleasure;
and repentance is no more than regret at haying
missed the way : so that, according to this sys¬
tem, a disinterested approbation of, and rever¬
ence for virtue, are no more possible than dis¬
interested affections towards our fellow-crea¬
tures. There is no sense of duty, no compunc¬
tion for our own offences, no indignation against
the crimes of others, unless they affect our own
safety; no secret cheerfulness shed over the
heart by the practice of welldoing. From his
philosophical writings it would be impossible to
conclude that there are in man a set of emotions,
desires, and aversions, of which the sole and final
objects are the voluntary actions and habitual
dispositions of himself and of all other voluntary
agents; which are properly called Moral Senti¬
ments ; and which, though they vary more in
degree, and depend more on cultivation, than
some other parts of human nature, are as seldom
as most of them found to be entirely wanting.
4. A theory of man which comprehends in its
explanations neither the social affections, nor the
moral sentiments, must be owned to be suffi¬
ciently defective. It is a consequence, or ra¬
ther a modification of it, that Hobbes should
constantly represent the deliberate regard to
personal advantage, as the only possible motive
of human action; and that he should altogether
disdain to avail himself of those refinements of
the selfish scheme which allow the pleasures of
benevolence and of morality, themselves, to be a
most important part of that interest which rea¬
sonable beings pursue.
5. Lastly, though Hobbes does in effect ac¬
knowledge the necessity of morals to society,
and the general coincidence of individual with
public interest—truths so palpable that they
never have been excluded from any ethical sys¬
tem—he betrays his utter want of moral sensibil¬
ity by the coarse and odious form in which he has
presented the first of these great principles ; and
his view of both leads him most strongly to sup¬
port that common and pernicious error of moral
reasoners, that a perception of the tendency of
good actions to preserve the being and promote
the wellbeing of the community, and a sense of
the dependence of our own happiness upon the
general security, either are essential constituents
of our moral feelings, or are ordinarily mingled
with the most effectual motives to right conduct.
The court of Charles II. were equally pleased
with Hobbes’s poignant brevity, and his low esti¬
mate of human motives. His ethical epigrams
became the current coin of profligate wits.
Sheffield, Duke of Buckinghamshire, who re¬
presented the class still more perfectly in his
morals than in his faculties, has expressed their
opinion in verses, of which one line is g6od
enough to be quoted :
Fame bears no fruit till the vain planter dies.
Dryden speaks of “ the philosopher and poet
(for such is the condescending term employed)
of Malmesbury,” as resembling Lucretius in
haughtiness. But Lucretius, though he held
many of the opinions of Hobbes, had the sensi¬
bility as well as genius of a poet. His dogma¬
tism is full of enthusiasm; and his philosophical
theory of society discovers occasionally as much
tenderness as can be shown without reference
to individuals. He was a Hobbist in only half
his nature.
The moral and political system of Hobbes was
a palace of ice, transparent, exactly proportioned,
majestic, admired by the unwary as a delight¬
ful dwelling; but gradually undermined by the
central warmth of human feeling, before it was
thawed into muddy water by the sunshine of
true philosophy.
When Leibnitz, in the beginning of the
eighteenth century, reviewed the moral writers
of modern times, his penetrating eye saw only
two who were capable of reducing morals and
jurisprudence to a science. (( So great an enter¬
prise,” says he, “ might have been executed by
the deep-searching genius of Hobbes, if he had
not set out from evil principles; or by the judg¬
ment and learning of the incomparable Grotius,
if his powers had not been scattered over many
1 Which he calls the pulchrum, for want, as he says, of an English word to express it. [Leviathan, Part i. c. vi.)
DISSERTATION SECOND.
339
subjects, and his mind distracted by the cares of
an agitated life.”1 Perhaps in this estimate,
admiration of the various and excellent quali¬
ties of Grotius may have overrated his purely
philosophical powers, great as they unquestion¬
ably were. Certainly the failure of Hobbes was
owing to no inferiority in strength of intellect.
Probably his fundamental errors may be im¬
puted, in part, to the faintness of his moral sen¬
sibilities, insufficient to make him familiar with
those sentiments and affections which can be
known only by being felt;—a faintness perfectly
compatible with his irreproachable life, but
which obstructed, and at last obliterated, the
only channel through which the most important
materials of ethical science enter into the mind.
Against Hobbes, says Warburton, the whole
church militant took up arms. The answers to
the Leviathan would form a library. But the
far greater part have followed the fate of all
controversial pamphlets. Sir Robert Filmer
was jealous of any rival theory of servitude.
Harrington defended liberty, and Clarendon the
church, against a common enemy. His philo¬
sophical antagonists were, Cumberland, Cud-
worth, Shaftesbury, Clarke, Butler, and Hutche¬
son. Though the last four writers cannot be
considered as properly polemics, their labours
were excited, and their doctrines modified, by
the stroke from a vigorous arm which seemed
to shake Ethics to its foundation. They lead us
far into the eighteenth century; and their works,
occasioned by the doctrines of Hobbes, sowed
the seed of the ethical writings of Hume, Smith,
Price, Kant, and Stewart; in a less degree, also,
of those of Tucker and Paley: not to mention
Mandeville, the buffoon and sophister of the
ale-house; or Helvetius, an ingenious but flimsy
writer, the low and loose moralist of the vain,
the selfish, and the sensual.
SECTION y.
Controversies concerning the Moral Faculties and the Social Affections.
CUMBERLAND—CUDWORTH—CLAltKE—SHAFTESBURY—BOSSUET—FENELON—LEIBNITZ—
MALEBRANCHE—EDWARDS—BUFFIER.
Dr Richard Cumberland,2 raised to the
see of Peterborough after the revolution of 1688,
was the only professed answerer of Hobbes. His
work on the Law of Nature still retains a place
on the shelf, though not often on the desk. The
philosophical epigrams of Hobbes form a con¬
trast to the verbose, prolix, and languid diction
of his answerer. The forms of scholastic argu¬
ment serve more to encumber his style than to
insure his exactness. But he has substantial
merits. He justly observes, that all men can
only be said to have had originally a right to all
things, in a sense in which right has the same
meaning with power. He shows that Hobbes is
at variance with himself; inasmuch as the dic¬
tates of right reason, which, by his own state¬
ment, teach men for their own safety to forego
the exercise of that right, and which he calls
Laws of Nature, are coeval with it; and that
mankind perceive the moral limits of their power
as clearly and as soon as they are conscious of
its existence. He enlarges the intimations of
Grotius on the social feelings, which prompt
men to the pleasures of pacific intercourse, as
certainly as the apprehension of danger and de¬
struction urges them to avoid hostility. The
1 “ Et tale aliquid potuisset vel ab incomparabilis Grotii judicio et doctrina, vel a profundo Hobbii ingenio prcestari ;
nisi ilium multa distraxissent; hie vero prava constituisset principia.” (Leibnitii Epist. ad Molanum ; IV. Pars iii. p. 276.)
' Born in 1632 ; died in 1718.
340
PRELIMINARY DISSERTATIONS.
fundamental principle of his Ethics is, that
•• the greatest benevolence of every rational
agent to all others is the happiest state of each
individual, as well as of the whole. 1 2 The
happiness accruing to each man from the obser¬
vance and cultivation of benevolence, he con¬
siders as appended to it by the supreme Ruler;
through which he sanctions it as his law, and
reveals it to the mind of every reasonable creature.
From this principle he deduces the rules of mo¬
rality, which he calls the Laws of Nature. The
surest, or rather only mark that they are the
commandments of God, is, that their observance
promotes the happiness of man : for that reason
alone could they he imposed by that Being whose
essence is love. As our moral faculties must to
us be the measure of all moral excellence, he
infers that the moral attributes of the Divinity
must in theirnatureheonly a transcendent degree
of those qualities which we most approve, love,
and revere, in those moral agents with whom we
are familiar. * He had a momentary glimpse of
the possibility that some human actions might
he performed with a view to the happiness of
others, without any consideration of the pleasure
reflected back on ourselves.3 But it is too faint
and transient to he worthy of observation, other¬
wise than as a new proof how often great truths
must flit before the understanding, before they
can be firmly and finally held in its grasp. His
only attempt to explain the nature of the moral
faculty, is the substitution of practical reason (a
phrase of the schoolmen, since become celebrat¬
ed from its renewal by Kant) for right reason ;4
and his definition of the first, as that which points
out the ends and means of action. Throughout
his whole reasoning, he adheres to the accustom¬
ed confusion of the quality which renders actions
virtuous, with the sentiments excited in us by the
contemplation of them. His language on the
identity of general and individual interest is ex¬
tremely vague; though it be, as he says, the
foundation-stone of the Temple of Concord
among men.
It is little wonder that Cumberland should not
have disembroiled this ancient and established
confusion, since Leibnitz himself, in a passage
where he reviews the theories of morals which
had gone before him, has done his utmost to
perpetuate it. “It is a question,” says he,
“ whether the preservation of human society be
the first principle of the law of nature. This
our author denies, in opposition to Grotius, who
laid down sociability to be so; to Hobbes, who
ascribed that character to mutual fear; and to
Cumberland, who held that it was mutual bene¬
volence ; which are all three only different names
for the safety and welfare of society.”5 Here
the great philosopher considered benevolence or
fear, two feelings of the human mind, to be the
first principles of the law of nature; in the same
sense in which the tendency of certain actions
to the wellbeing of the community may he so
regarded. The confusion, however, was then
common to him with many, as it even now is
with most. The comprehensive view was his
own. He perceives the close resemblance of
these various and even conflicting opinions, in
that important point of view in which they re¬
late to the effects of moral and immoral actions
on the general interest. The tendency of virtue
to preserve amicable intercourse was enforced
by Grotius; its tendency to prevent injury was
dwelt on by Hobbes; its tendency to promote
an interchange of benefits was inculcated by
Cumberland.
1 Cumberland de Lcgibus Naturae, cap. i. sect. 12. first published in London, 1672, and then so popular as to be reprint¬
ed at Lubeck in 1683.
2 Ibid. cap. v. sect. 19.
3 Ibid. cap. ii. sect. 20.
* “ Whoever determines his judgment and his will by right reason, must agree with all others who judge according to
right reason in the same matter.” {Ibid. cap. ii. sect. 8.) This is in one sense only a particular instance of the identical proposi¬
tion, that two things which agree with a third thing must agree with each other in that in which they agree with the third.
But the difficulty entirely consists in the particular third thing here introduced, namely, “ right reason,” the nature of
which not one step is made to explain. The position is curious, as coinciding with “ the universal catego^cal imperative,”
adopted as a first principle by Kant.
5 Leibn. IV. Pars iii. p. 271. The unnamed work which occasioned these remarks (perhaps one of Thomasius) appeared
m 1699. How long after this Leibnitz’s Dissertation was written, does not appear.
DISSERTATION SECOND.
341
CUD WORTH.1 *
Cudworth, one of the eminent men educated
or promoted in the English Universities during
the Puritan rule, was one of the most distinguish¬
ed of the Latitudinarian or Arminian party who
came forth at the Restoration, with a love of liber¬
ty imbibed from their Calvinistic masters, as well
as from the writings of antiquity, yet tempered
by the experience of their own agitated age; and
with a spirit of religious toleration more impar¬
tial and mature, though less systematic and
professedly comprehensive, than that of the In¬
dependents, the first sect who preached that
doctrine. Taught by the errors of their time,
they considered religion as consisting, not in
vain efforts to explain unsearchable mysteries,
but in purity of heart exalted by pious feelings,
and manifested by virtuous conduct.3 The go¬
vernment of the church was placed in their
hands by the revolution, and their influence
was long felt among its rulers and luminaries.
The first generation of their scholars turned
their attention too much from the cultivation of
the heart to the mere government of outward
action; and in succeeding times the tolerant
spirit, not natural to an establishment, was with
difficulty kept up by a government whose ex¬
istence depended on discouraging intolerant pre¬
tensions. No sooner had the first sketch of the
Hobbian phildsophy5 been privately circulated at
Paris, than Cudworth seized the earliest oppor¬
tunity of sounding the alarm against the most
justly odious of the modes of thinking which it
cultivates, or forms of expression which it would
introduce;4 the prelude to a war which occu¬
pied the remaining forty years of his life. The
Intellectual System, his great production, is di¬
rected against the atheistical opinions of Hobbes:
it touches ethical questions but occasionally and
incidentally. It is a work of stupendous ei u-
dition, of much more acuteness than at first
appears, of frequent mastery over diction and
illustration on subjects where it is most rare;
and it is distinguished, perhaps beyond any
other volume of controversy, by that best proof
of the deepest conviction of the truth of a man s
principles, a fearless statement of the most for¬
midable objections to them; a fairness rarely
practised but by him who is conscious of his
power to answer them. In all his writings, it
must be owned, that his learning obscures his
reasonings, and seems even to oppress his pow¬
erful intellect. It is an unfortunate effect of
the redundant fulness of his mind, that it over¬
flows in endless digressions, which break the
chain of argument, and turn aside the thoughts
of the reader from the main object. He was edu¬
cated before usage had limited the naturaliza¬
tion of new words from the learned languages;
before the failure of those great men, from Bacon
to Milton, who laboured to follow a Latin order
in their sentences,—and the success of those men
of inferior powers, from Cowley to Addison, who
were content with the order, as well as the
words, of pure and elegant conversation,—had,
as it were, by a double series of experiments,
ascertained that the involutions and inversions
of the ancient languages are seldom reconcil¬
able with the genius of ours; and, unless skil¬
fully, as well as sparingly introduced, are at
variance with the natural beauties of our prose
composition. His mind was more that of an an¬
cient than of a modern philosopher. He often
l SeTthe Sifulfccounfof them by Burnet, {Hist. I. 321, Oxford edit. 1823) who was himself one of the most dis¬
tinguished ofthis excellent body; with whom may be classed notwithstanding some of doctnnal difference^ early
master Leiehton bishon of Dunblane, a beautiful writer, and one of the best of men. the earliest account ot t ■
a curious contemporary pamphlet, entitled, An Account of the new Sect of
the coUection of tracts entitled, Phcmix Britannicus. Jeremy Taylor deserves the,^ ^ar ot
place among them. But Cudworth’s excellent sermon before the House of Commons (31st March 11 7) tyliberai
the publication of Taylor’s Liberty of Prophesying, may be compared even to Taylor m charity, piety, and the most
toleration.
4 Dantur boni et mali rationes ceternoe et indispensabiles. Thesis for the degree of B.D. at Cambridge in 1644. (Lircu a
Life of Cudworth, prefixed to his edition of the Intellectual System, p. vin Lond. 1743. 2 vols. 4to.)
342
PRELIMINARY DISSERTATIONS.
indulged in that sort of amalgamation of fancy
with speculation, the delight of the Alexandrian
doctors, with whom he was most familiarly con¬
versant ; and the Intellectual System, both in
thought and expression, has an old and foreign
air, not unlike a translation from the work of a
later Platonist. Large ethical works of this
eminent writer are extant in manuscript in the
British Museum.1 * 3 One posthumous volume
on morals was published by Dr Chandler, bishop
of Durham, entitled, A Treatise concerning Eter¬
nal and Immutable Morality. “ But there is the
more reason to regret (as far as relates to the
history of opinion) that the larger treatises are
still unpublished, because the above volume is
not so much an ethical treatise as an introduc¬
tion to one. Protagoras of old, and Hobbes then
alive, having concluded that right and wrong
were unreal, because they were not perceived
by the senses, and because all human knowledge
consists only in such perception, Cudworth en¬
deavours to refute them, by disproving that part
of their premises which forms the last-stated
proposition. The mind has many conceptions
(vwj/xara) which are not cognizable by the senses;
and though they are occasioned by sensible ob¬
jects, yet could not be formed but by a faculty
superior to sense. The conceptions of justice
and duty he places among them. The distinction
of right from wrong is discerned by reason;
and as soon as these words are defined, it be¬
comes evident that it would be a contradiction
in terms to affirm that any power, human or
divine, could change their nature; or, in other
words, make the same act to be just and unjust
at the same time. They had existed eternally,
in the only mode in which truths can he said to
be eternal, in the Eternal Mind; and they were
indestructible and unchangeable like that Su¬
preme Intelligence.5
Whatever judgment may he formed of this
reasoning, it is manifest that it relates merely
to the philosophy of the understanding, and does
not attempt any explanation of what constitutes
the very essence of morality, its relation to the
will. That we perceive a distinction between
right and wrong as much as between a triangle
and a square, is indeed true; and may possibly
lead to an explanation of the reason why men
should adhere to the one and avoid the other.
But it is not that reason. A command or a
precept is not a proposition. It cannot he said
that either is true or false. Cudworth, as well
as many who succeeded him, confounded the
mere apprehension by the understanding that
right is different from wrong, with the practical
authority of these important conceptions, exer¬
cised over voluntary actions, in a totally distinct
province of the human soul.
Though his life was devoted to the assertion
of divine Providence, and though his philosophy
was imbued with the religious spirit of Plato¬
nism, 4 yet he had placed Christianity too purely
in the love of God and man to be considered as
having much regard for those controversies about
rites and opinions with which zealots disturb
the world. They represented him as having
fallen into the same heresy with Milton and
with Clarke;5 and some of them even charged
him with atheism, for no other reason than that
he was not afraid to state the atheistic difficul¬
ties in their fullest force. As blind anger heaps
inconsistent accusations on each other, they call¬
ed him at least 4 4 an Arian, a Socinian, or a
Deist.”6 The courtiers of Charles II., who were
delighted with every part of Hobbes hut his in-
1 A curious account of the history of these MSS. by Dr Kippis, is to be found in the Biographia Britannica, IY. 549.
* London, 1731, 8vo.
3 “ There are many objects of our mind which we can neither see, hear, feel, smell, nor taste, and which did never en¬
ter into it by any sense; and therefore we can have no sensible pictures or ideas of them, drawn by the pencil of that
inward limner or painter which borrows all his colours from sense, which we call Fancy: and if we reflect on our own
cogitations of these things, we shall sensibly perceive that they are not phantastical, but noematical: as, for example, justice,
equity, duty and obligation, cogitation, opinion, intellection, volition, memory, verity, falsity, cause, effect, genus, species,
nullity, contingency, possibility, impossibility, and innumerable others.” {Eternal and Immutable Morality, p. 140.) We
have here an anticipation of Kant.
4 Evcnliu, a tsxvsv, o tutri/iiav ax^us x^Krrtavigti. Be pious, my son, for piety is the sum of Christianity. (Motto affixed
to the sermon above mentioned.)
s The following doctrine is ascribed to Cudworth by Nelson, a man of good understanding and great worth: “ Dr Cud¬
worth maintained that the Father, absolutely speaking, is the only supreme God ; the Son and Spirit being God only by
his concurrence with them, and their subordination and subjection to him.” (Nelson’s Life of Bull, p. 339.)
s Turner’s Discourse on the Messiah, p. 335.
DISSERTATION SECOND.
343
tegrity, did their utmost to decry his antagonist.
They turned the railing of the bigots into a
sarcasm against religion; as we learn from him
who represented them with unfortunate fidelity.
“ He has raised,” says Dryden, “ such strong
objections against the being of God, that many
think he has not answered them—“ the com¬
mon fate,” as Lord Shaftesbury tells us, “of those
who dare to appear fair authors.”1 He had, in¬
deed, earned the hatred of some theologians,
better than they could know from the writings
published during his life; for in his posthumous
work he classes with the ancient atheists those of
his contemporaries, whom he forbears to name,
who held “ that God may command what is con¬
trary to moral rules; that he has no inclination to
the good of his creatures; that he may justly doom
an innocent being to eternal torments; and that
whatever God does will, for that reason is just,
because he wills it.”2 It is an interesting inci¬
dent in the life of a philosopher, that Cudworth’s
daughter, Lady Masham, had the honour to nurse
the infirmities and to watch the last breath of Mr
Locke, who was opposed to her father in specu¬
lative philosophy, but who heartily agreed with
him in the love of truth, liberty, and virtue.
CLARKE.3
Connected with Cud worth by principle, tho ugh
separated by some interval of time, was Dr
Samuel Clarke, a man eminent at once as a di¬
vine, a mathematician, a metaphysical philoso¬
pher, and a philologer; who, as the interpreter of
Homer and Caesar, the scholar of Newton, and
the antagonist of Leibnitz, approved himself not
unworthy of correspondence with the highest
order of human spirits. Roused by the preva¬
lence of the doctrines of Spinoza and Hobbes, he
endeavoured to demonstrate the being and attri¬
butes of God, from a few axioms and definitions,
in the manner of geometry; an attempt in which,
with all his powers of argument, it must be
owned that he is compelled sometimes tacitly
to assume what the laws of reasoning required
him to prove; and that, on the whole, his failure
may be regarded as a proof that such a mode
of argument is beyond the faculties of man.4
Justly considering the moral attributes of the
Deity as what alone renders him the object of
religion, and to us constitutes the difference be¬
tween theism and atheism, he laboured with
the utmost zeal to place the distinctions of right
and wrong on a more solid foundation ; and to
explain the conformity of morality to reason, in
a manner calculated to give a precise and scien¬
tific signification to that phraseology which all
philosophers had, for so many ages, been content
to employ, without thinking themselves obliged
to define.
It is one of the most rarely successful efforts
of the human mind, to place the understanding
at the point from which a philosopher takes the
views that compose his system, to recollect con¬
stantly his purposes, to adopt for a moment his
previous opinions and prepossessions, to think
in his words and to see with his eyes; especially
when the writer widely dissents from the sys¬
tem which he attempts to describe, and after a
general change in the modes of thinking and in
the use of terms. Every part of the present
Dissertation requires such an excuse; but perhaps
it may be more necessary in a case like that of
Clarke, where the alterations in both respects
have been so insensible, and in some respects
appear so limited, that they may escape atten¬
tion, than after those total revolutions in doc-
1 Moralists, Part ii. sect. 3.
2 Eternal and Immutable Morality, p. 11. He names only one book published at Franeker. He quotes Ockham as having
formerly maintained the same monstrous positions. To many, if not to most of these opinions or expressions, ancient and
modern, reservations are adjoined, which render them literally reconcilable with practical morals. But the dangerous abuse
to which the incautious language of ethical theories is liable, is well illustrated by an anecdote related in Plutarch’s Life
of Alexander. A sycophant named Anaxarchas consoled that monarch for the murder of Clitus, by assuring him that
every act of a ruler must be just. Uav to Toaxfav uvro too xparouvros Itxxiov. (Plut. Over. I. 639. Franc. 1599.)
4 Born m 1675 ; died in 1729.
4 This admirable person had so much candour as in effect to own his failure, and to recur to those other arguments in
support of this great truth, which have in all ages satisfied the most elevated minds. In Proposition viii. {Being and Attri¬
butes of God, p. 47) which affirms that the first cause must be “ intelligent,” (where, as he truly states, “ lies the main question
between us and the atheists”) he owns, that the proposition cannot be demonstrated strictly and properly a priori.
See Notes and Illustrations, note M.
344
PRELIMINARY DISSERTATIONS.
trine, where the necessity of not measuring
other times by our own standard must be ap¬
parent to the most undistinguishing.
The sum of his moral doctrine may he stated
as follows. Man can conceive nothing without
at the same time conceiving its relations to other
things. He must ascribe the same law of per¬
ception to every being to whom he ascribes
thought. He cannot therefore doubt that all
the relations of all things to all must have al¬
ways been present to the Eternal Mind. The re¬
lations in this sense are eternal, however recent
the things may be between whom they subsist.
The whole of these relations constitute truth.
The knowledge of them is omniscience. These
eternal different relations of things involve a
consequent eternal fitness or unfitness in the ap¬
plication of things one to another; with a re¬
gard to which, the will of God always chooses,
and which ought likewise to determine the wills
of all subordinate rational beings. These eter¬
nal differences make it fit and reasonable for the
creatures so to act; they cause it to be their
duty, or lay an obligation on them so to do, se¬
parate from the will of God,1 * and antecedent to
any prospect of advantage or reward.3 Nay,
wilful wickedness is the same absurdity and
insolence in morals, as it would he in natural
things to pretend to alter the relations of num¬
bers, or to take away the properties of ma¬
thematical figures.3 “Morality,” says one of
his most ingenious scholars, “ is the practice of
reason.”4
Clarke, like Cudworth, considered such a
scheme as the only security against Hobbism,
and probably against the Calvinistic theology,
from which they were almost as averse. Not
content, with Cumberland, to attack Hobbes on
ground which was in part his own, they thought
it necessary to build on entirely new founda¬
tions. Clarke more especially, instead of sub¬
stituting social and generous feeling for the self¬
ish appetites, endeavoured to bestow on morality
the highest dignity, by thus deriving it from
reason. He made it more than disinterested ;
for he placed its seat in a region where interest
never enters, and passion never disturbs. By
ranking her principles with the first truths of
science, he seemed to render them pure and im¬
partial, infallible and unchangeable. It might
be excusable to regret the failure of so noble an
attempt, if the indulgence of such regrets did
not betray an unworthy apprehension that the
same excellent ends could only be attained by
such frail means; and that the dictates of the
most severe reason would not finally prove re¬
concilable with the majesty of virtue.
REMARKS.
The adoption of mathematical forms and
terms was, inEngland, a prevalent fashion among
writers on moral subjects during a large part of
the eighteenth century. The ambition of mathe¬
matical certainty, on matters concerning which
it is not given to man to reach it, is a frailty
from which the disciple of Newton ought in
reason to have been withheld, but to which he
was naturally tempted by the example of his
master. Nothing but the extreme difficulty of
detaching assent from forms of expression to
which it has been long wedded, can explain the
fact, that the incautious expressions above cited,
into which Clarke was hurried by his moral
sensibility, did not awaken him to a sense of the
error into which he had fall en. As soon as he had
said that “ a wicked act was as absurd as an
attempt to take away the properties of a figure,”
he ought to have seen, that principles which led
logically to such a conclusion were untrue. As
it is an impossibility to make three and three
cease to be six, it ought, on his principles, to be
impossible to do a wicked act. To act without
regard to the relations of things, as if a man were
to choose fire for cooling, or ice for heating, would
be the part either of a lunatic or an idiot. The
murderer who poisons by arsenic, acts agreeably
to his knowledge of the power of that substance
to kill, which is a relation between two things ;
1 “ Those who found all moral obligation on the will of God must recur to the same thing, only they do not explain
how the nature and will of God is good and just.” (Being and Attributes of God, Proposition xii.)
1 Evidence of Natural and Revealed Religion, p. 4, 6th edit. Lond. 1724.
3 Ibid. p. 42.
* Low MAN on the Unity and Perfections of God, p. 29. Lond. 1737*
DISSERTATION SECOND.
345
as much as the physician who employs an emetic
after the poison, acts upon his belief of the ten¬
dency of that remedy to preserve life, which is
another relation between two things. All men
who seek a good or had end by good or bad means,
must alike conform their conduct to some rela¬
tion between their actions as means and their
object as an end. All the relations of inanimate
things to each other are undoubtedly observed
as much by the criminal as by the man of virtue.
It is therefore singular that Dr Clarke suffer¬
ed himself to be misled into the representation,
that virtue is a conformity with the relations of
things universally, vice a universal disregard
of them, by the certain, but here insufficient truth,
that the former necessarily implied a regard to
certain particular relations, which were always
disregarded by those who chose the latter. The
distinction between right and wrong can, there¬
fore, no longer depend on relations as such, but
on a particular class of relations. And it seems
evident that no relations are to be considered, ex¬
cept those in which a living, intelligent, and
voluntary agent is one of the beings related.
His acts may relate to a law, as either observing
or infringing it; they may relate to his own mo¬
ral sentiments and those of his fellows, as they
are the objects of approbation or disapprobation;
they may relate to his own welfare, by increas¬
ing or abating it; they may relate to the well¬
being of other sentient beings, by contributing
to promote or obstruct it: but in all these, and
in all supposable cases, the inquiry of the moral
philosopher must be, not whether there be a re¬
lation, but what the relation is; whether it be
that of obedience of law, or agreeableness to
moral feeling, or suitableness to prudence, or
coincidence with benevolence. The term rela¬
tion itself, on which Dr Clarke’s system rests,
being common to right and wrong, must be
struck out of the reasoning. He himself inci¬
dentally drops intimations which are at variance
with his system. “ The Deity,” he tells us,
“ acts according to the eternal relations of things,
in order to the welfare of the whole universe
and subordinate moral agents ought to be go¬
verned by the same rules, “ for the good of the
public.”1 No one can fail to observe that a new
element is here introduced—the wellbeing of
communities of men, and the general happiness
of the world—which supersedes the consideration
of abstract relations and fitnesses.
There are other views of this system, how¬
ever, of a more general nature, and of much
more importance, because they extend in a con¬
siderable degree to all systems which found
moral distinctions or sentiments, solely or ulti¬
mately, upon reason. A little reflection will
discover an extraordinary vacuity in this sys¬
tem. Supposing it were allowed that it satis¬
factorily accounts for moral judgments, there is
still an important part of our moral sentiments
which it passes by without an attempt to ex¬
plain them. Whence, on this scheme, the plea¬
sure or pain with which we review our own ac¬
tions, or survey those of others ? What is tho
nature of remorse ? Why do we feel shame ?
Whence is indignation against injustice ? These
are surely no exercise of reason. Nor is the as¬
sent of reason to any other class of propositions
followed or accompanied by emotions of this na¬
ture, by any approaching them, or indeed neces¬
sarily by any emotion at all. It is a fatal objec¬
tion to a moral theory, that it contains no means
of explaining the most conspicuous, if not the
most essential, parts of moral approbation and
disapprobation.
But to rise to a more general consideration :
Perception and emotion are states of mind per¬
fectly distinct; and an emotion of pleasure or
pain differs much more from a mere perception,
than the perceptions of one sense do from those
of another. The perceptions of all the senses
have some qualities in common. But an emo¬
tion has not necessarily anything in common
with a perception, but that they are both states
of mind. We perceive exactly the same quali¬
ties in coffee when we may dislike it, as after¬
wards when we come to like it. In other words,
the perception remains the same when the sen¬
sation of pain is changed into the opposite sen¬
sation of pleasure. The like change may oc¬
cur in every case where pleasure or pain (in
such instances called sensations) enter the mind
2 X
DISS. II.
1 Evidence of Natural and Revealed Religion, p. 4.
346
PRELIMINARY DISSERTATIONS.
with perceptions through the eye or the ear.
The prospect or the sound which was disagree¬
able may become agreeable, without any altera¬
tion in our idea ot the objects. We can easily
imagine a percipient and thinking being without
a capacity of receiving pleasure or pain. Such
a being might perceive what we do 5 if we could
conceive him to reason, he might reason justly ;
and if he were to judge at all, there seems no
reason why he should not judge truly. But
what could induce such a being to will or to act ?
It seems evident that his existence could only
be a state of passive contemplation. Reason, as
reason, can never be a motive to action. It is
only when we superadd to such a being sensi¬
bility, or the capacity of emotion or sentiment,
(or what in corporeal cases is called sensation)
of desire and aversion, that we introduce him
into the world of action. We then clearly dis¬
cern, that when the conclusion of a process of
reasoning presents to his mind an object of de¬
sire, or the means of obtaining it, a motive of
action begins to operate; and reason may then,
but not till then, have a powerful though indi¬
rect influence on conduct. Let any argument
to dissuade a man from immorality be employ¬
ed, and the issue of it will always appear to be
an appeal to a feeling. You prove that drunk¬
enness will probably ruin health. No position
founded on experience is more certain. Most
persons with whom you reason must he as much
convinced of it as you are. But your hope of
success depends on the drunkard’s fear of ill
health; and he may always silence your argu¬
ment by telling you that he loves wine more
than he dreads sickness. You speak in vain
of the infamy of an act to one who disre¬
gards the opinion of others; or of its impru¬
dence to a man of little feeling for his own fu¬
ture condition. You may truly, but vainly, tell
of the pleasures of friendship to one who has
little affection. If you display the delights ot
liberality to a miser, he may always shut your
mouth by answering, “ The spendthrift may pre¬
fer such pleasures; I love money more.” If
you even appeal to a man’s conscience, he may
answer you, that you have clearly proved the im¬
morality of the act, and that he himself knew it
before; but that now when you had renewed and
freshened his conviction, he was obliged to own,
that his love of virtue, even aided by the fear ot
dishonour, remorse, and punishment, was not so
powerful as the desire which hurried him into vice.
Nor is it otherwise, however confusion of ideas
may cause it to be so deemed, with that calm re¬
gard to the welfare of the agent, to which philo¬
sophers have so grossly misapplied the hardly in¬
telligible appellation of self-love. The general
tendency of right conduct to permanent wellbeing
is indeed one of the most evident of all truths.
But the success of persuasives or dissuasives ad¬
dressed to it, must always be directly propor¬
tioned, not to the clearness with which the truth
is discerned, hut to the strength of the principle
addressed, in the mind of the individual; and to
the degree in which he is accustomed to keep an
eye on its dictates. A strange prejudice pre¬
vails, which ascribes to what is called self-love
an invariable superiority over all the other mo¬
tives of human action. If it were to be called
by a more fit name, such as foresight, prudence,
or, what seems most exactly to describe its na¬
ture, a sympathy with the future feelings of the
agent, it would appear to every observer to he,
very often, too languid and inactive, always of
late appearance, and, sometimes, so faint as to
be scarcely perceptible. Almost every human
passion in its turn prevails over self-love.
It is thus apparent that the influence of reason
on the will is indirect, and arises only from its
being one of the channels by which the objects
of desire or aversion are brought near to these
springs of voluntary action. It is only one of
these channels. There are many other modes
of presenting to the mind the proper objects of
the emotions which it is intended to excite,
whether of a calmer or of a more active nature;
so that they may influence conduct more power¬
fully than when they reach the will through the
channel of conviction. The distinction between
conviction and persuasion would indeed be other¬
wise without a meaning: to teach the mind would
be the same thing as to move it; and eloquence
would he nothing hut logic, although the greater
part of the power of the former is displayed in
the direct excitement of feeling;—on condition,
indeed, (for reasons foreign to our present pur¬
pose) that the orator shall never appear to give
DISSERTATION SECOND.
347
counsel inconsistent with the duty or the lasting
welfare of those whom he would persuade. In
like manner it is to he observed, that though
reasoning be one of the instruments of education,
yet education is not a proof of reasoning, hut a
wise disposal of all the circumstances which in¬
fluence character, and of the means of producing
those habitual dispositions which insure well¬
doing, of which reasoning is hut one. Very
similar observations are applicable to the great
arts of legislation and government; which are
here only alluded to as forming a strong illustra¬
tion of the present argument.
The abusive extension of the term Beason to
the moral faculties, one of the predominant
errors of ancient and modern times, has arisen
from causes which it is not difficult to discover.
Reason does in truth perform a great part in
every case of moral sentiment. To reason often
belong the preliminaries of the act; to reason
altogether belongs the choice of the means of
execution. The operations of reason, in both
cases, are comparatively slow and lasting; they
are capable of being distinctly recalled by mem¬
ory. The emotion which intervenes between
the previous and the succeeding exertions of
reason is often faint, generally transient, and
scarcely ever capable of being reproduced by an
effort of the mind. Hence the name of reason
is applied to this mixed state of mind; more
especially when the feeling, being of a cold and
general nature, and scarcely ruffling the sur¬
face of the soul, such as those of prudence and
of ordinary kindness and propriety, almost passes
unnoticed, and is irretrievably forgotten. Hence
the mind is, in such conditions, said by moralists
to actfrom reason, in contradistinction to its more
excited and disturbed state, when it is said to
act from passion. The calmness of reason gives
to the whole compound the appearance of un-
mixed reason. The illusion is further promoted
by a mode of expression used in most languages.
A man is said to act reasonably, when his con¬
duct is such as may he reasonably expected.
Amidst the disorders of a vicious mind, it is
difficult to form a reasonable conjecture con¬
cerning future conduct; but the quiet and well-
ordered state of virtue renders the probable acts
of her fortunate votaries the object of very ra¬
tional expectation.
As far as it is not presumptuous to attempt a
distinction between modes of thinking foreign
to the mind which makes the attempt, and modes
of expression scarcely translatable into the only
technical language in which that mind is wont
to think, it seems that the systems of Cudworth
and Clarke, though they appear very similar,
are in reality different in some important points
of view. The former, a Platonist, sets out from
those Ideas, (a word, in this acceptation of it,
which has no corresponding term in English)
the eternal models of created things, which, as
the Athenian master taught, pre-existed in the
everlasting intellect, and, of right, rule the will
of every inferior mind. The illustrious scholar
of Newton, with a manner of thinking more
natural to his age and school, considered pri¬
marily the very relations of things themselves ;
conceived indeed by the Eternal Mind, but
which, if such inadequate language maybe par¬
doned, are the law of its will, as well as the
model of its works.1
EARL OF SHAFTESBURY.*
Lord Shaftesbury, the author of the CAarac- vices, the bitter fruits of the insecurity of a
teristics, was the grandson of Sir Antony Ashley troublous time, succeeded by the corrupting ha-
Cooper, created Earl of Shaftesbury, one of bits of an inconstant, venal, and profligate court,
the master spirits of the English nation, whose have led an ungrateful posterity to overlook his
1 Mr Wollaston’s system, that morality consisted in acting according to truth, seems to coincide with that of Dr Clarke.
The murder of Cicero by Popilius Lenas, was, according to him, a practical falsehood ; for Cicero had been his benefactor,
but Popilius acted as if that were untrue. If the truth spoken of be, that gratitude is due for benefits, the reasoning is
evidently a circle. If any truth be meant, indifferently, it is plain that the assassin acted in perfect conformity to several
certain truths; such as the malignity of Antony, the ingratitude and venality of Popilius, and the probable impunity of his
crime, when law was suspended, and good men without power.
* Born in 1671; died in 1713.
348
PRELIMINARY DISSERTATIONS.
wisdom, and disinterested perseverance, in ob¬
taining for the English nation the unspeakable
benefits of the Habeas Corpus act. The for¬
tune of the Characteristics has been singular.
For a time the work was admired more undis-
tinguishingly than its literary character war¬
rants. In the succeeding period it was justly
criticised, hut too severely condemned. Of
late, more unjustly than in either of the former
cases, it has been generally neglected. It seemed
to have the power of changing the temper of its
critics. It provoked the amiable Berkeley to a
harshness equally unwonted and unwarranted;1 2
while it softened the rugged Warburton so far
as to dispose the fierce yet not altogether un¬
generous polemic to praise an enemy in the
very heat of conflict.8
Leibnitz, the most celebrated of Continental
philosophers, warmly applauded the Character¬
istics, and, (what was a more certain proof of
admiration) though at an advanced age, cri¬
ticised that work minutely.3 * * * * Le Cl ere, who
had assisted the studies of the author, contri¬
buted to spread its reputation by his Journal,
then the most popular in Europe. Locke is
said to have aided in his education, probably
rather by counsel than by tuition. The author
had indeed been driven from the regular stu¬
dies of his country by the insults with which he
was loaded at Winchester school, when he was
only twelve years old, immediately after the
death of his grandfather; a choice of time which
seemed not so much to indicate anger against
the faults of a great man, as triumph over
the principles of liberty, which seemed at that
time to have fallen for ever. He gave a gen¬
uine proof of respect for freedom of thought,
by preventing the expulsion, from Holland, of
Bayle, (with whom he differs in every moral,
political, and, it may be truly added, religious
opinion) when, it must be owned, the right of
asylum was, in strict justice, forfeited by the se¬
cret services which the philosopher had rendered
to the enemy of Holland and of Europe. In
the small part of his short life which premature
infirmities allowed him to apply to public affairs,
he co-operated zealously with the friends of
freedom; but, as became a moral philosopher,
he supported, even against them, a law to allow
those who were accused of treason to make their
defence by counsel, although the parties first to
benefit from this act of imperfect justice were
conspirators to assassinate King William, and
to re-enslave their country. On that occasion
it is well known with what admirable quickness
he took advantage of the embarrassment which
seized him, when he rose to address the House
of Commons. “ If I,” said he, “ who rise only
to give my opinion on this bill, am so confound¬
ed that I cannot say what I intended, what
must the condition of that man be, who, with¬
out assistance, is pleading for his own life !” He
was the friend of Lord Somers; and the tribute
paid to his personal character by Warburton,
who knew many of his contemporaries and some
of his friends, may be considered as evidence of
its excellence.
His fine genius and generous spirit shine
through his writings; but their lustre is often
dimmed by peculiarities, and, it must be said,
by affectations, which, originating in local, tem¬
porary, or even personal circumstances, are
particularly fatal to the permanence of fame.
There is often a charm in the egotism of an art¬
less writer, or of an actor in great scenes. But
other laws are imposed on the literary artist.
Lord Shaftesbury, instead of hiding himself be¬
hind his work, stands forward with too frequent
marks of self-complacency, as a nobleman of
polished manners, with a mind adorned by the
1 Berkeley’s Minute Philosopher, Dialogue iii.; but especially his Theory of Vision Vindicated, Loud. 1733, (not re¬
published in the quarto edition of his works) where this most excellent man sinks for a moment to the level of a railing
polemic.
2 It is remarkable that the most impure passages of Warburton’s composition are those in which he lets loose his contro¬
versial zeal, and that he is a fine writer principally where he writes from generous feeling. “ Of all the virtues which were
so much in this noble writer’s heart and in his writings, there was not one he more revered than the love of public liberty.
...The noble author of the Characteristics had many excellent qualities, both as a man and a writer. He was temperate,
chaste, honest, and a lover of his country. In his writings he has shown how much he has imbibed the deep sense, and how
naturally he could copy the gracious manner, of Plato.” (Dedication to the Freethinkers, prefixed to the Divine Legation.)
Warburton, however, soon relapses, but not without excuse; for he thought himself vindicating the memory of Locke.
* Opera, tom. III. p. 39-56.
DISSERTATION SECOND.
349
fine arts, and instructed by ancient philosophy;
shrinking with a somewhat effeminate fastid¬
iousness from the clamour and prejudices of
the multitude, whom he neither deigns to con¬
ciliate nor puts forth his strength to subdue.
The enmity of the majority of churchmen to the
government established at the Revolution, was
calculated to fill his mind with angry feelings;
which overflow too often, if not upon Christian¬
ity itself, yet upon representations of it, closely
intertwined with those religious feelings to which,
in other forms, his own philosophy ascribes sur¬
passing worth. His small, and occasional writ¬
ings, of which the main fault is the want of an
object or a plan, have many passages remark¬
able for the utmost beauty and harmony of lan¬
guage. Had he imbibed the simplicity, as well
as copied the expression and cadence of the
greater ancients, he would have done more jus¬
tice to his genius; and his works, like theirs,
would have been preserved by that quality, with¬
out which but a very few writings, of whatever
mental power, have long survived their writers.
Grace belongs only to natural movements; and
Lord Shaftesbury, notwithstanding the frequent
beauty of his thoughts and language, has rarely
attained it. He is unfortunately prone to plea¬
santry, which is obstinately averse from con¬
straint, and which he had no interest in raising to
be the test of truth. His affectation of liveliness
as a man of the world, tempts him sometimes to
overstep the indistinct boundaries which sepa¬
rate familiarity from vulgarity. Of his two
more considerable writings, the Moralists, on
which he evidently most valued himself, and
which is spoken of by Leibnitz with enthusiasm,
is by no means the happiest. Yet perhaps there
is scarcely any composition in our language
more lofty in its moral and religious sentiments,
and more exquisitely elegant and musical in
its diction, than the Platonic representation of
the scale of beauty and love, in the speech to
Palemon, near the close of the first part.1 *
Many passages might be quoted, which in some
measure justify the enthusiasm of the septuage¬
narian geometer. Yet it is not to be concealed
that, as a whole, it is heavy and languid. It is
a modern antique. The dialogues of Plato are
often very lively representations of conversations
which might take place daily at a great univer¬
sity, full, like Athens, of rival professors and eager
disciples,—^between men of various character,
and great fame as well as ability. Socrates runs
through them all. His great abilities, his still
more venerable virtues, his cruel fate, especially
when joined to his very characteristic pecu¬
liarities,—to his grave humour, to his homely
sense, to his assumed humility, to the honest
sliness with which he ensnared the Sophists,
and to the intrepidity with which he dragged
them to justice, gave unity and dramatic inter¬
est to these dialogues as a whole. But Lord
Shaftesbury’s dialogue is between fictitious per¬
sonages, and in a tone at utter variance with
English conversation. He had great power of
thought and command over words. But he had
no talent for inventing character and bestowing
life on it. The Inquiry concerning Virtue* is
nearly exempt from the faulty peculiarities of the
author; the method is perfect, the reasoning just,
the style precise and clear. The writer has no
purpose but that of honestly proving his prin¬
ciples; he himself altogether disappears; and
he is intent only on earnestly enforcing what he
truly, conscientiously, and reasonably believes.
Hence the charm of simplicity is revived in this
production, which is unquestionably entitled to
a place in the first rank of English tracts on
Moral Philosophy.
The point in which it becomes especially per¬
tinent to the subject of this Dissertation is, that it
contains more intimations of an original and
important nature on the Theory of Ethics than
perhaps any preceding work of modern times.3
It is true that they are often but intimations,
cursory, and appearing almost to be casual; so
that many of them have escaped the notice of
most readers, and even writers on these subjects.
1 Characteristics, Treatise v. The Moralists, Part i. sect. 3.
* Ibid. Treatise iv.
* I am not without suspicion that I have overlooked the claims of Dr Henry More, who, notwithstanding
couthness of language, seems to have given the first intimations of a distinct moral faculty, which he calls the _ om orm
Facultya phrase against which an outcry would now be raised as German. Happiness, according to him, consis s m a
constant satisfaction, tv uyaDoidu rns ■4'vzks- {Enchiridion Ethicum, lib. i. cap. ii.)
350
PRELIMINARY DISSERTATIONS.
That the consequences of some of them are even
yet not unfolded, must he owned to he a proof
that they are inadequately stated; and may he
regarded as a presumption that the author did
not closely examine the hearings of his own po¬
sitions. Among the most important of these
suggestions is, the existence of dispositions in
man, hy which he takes pleasure in the wellbeing
of others, without any further view; a doctrine,
however, to all the consequences of which he
has not been faithful in his other writings.1
Another is, that goodness consists in the preva¬
lence of love for the system of which we are a
part, over the passions, pointing to our indi¬
vidual welfare; a proposition which somewhat
confounds the motives of right acts with their
tendency, and seems to favour the melting of all
particular affections into general benevolence,
because the tendency of these affections is to
general good. The next, and certainly the most
original, as well as important, is, that there are
certain affections of the mind which, being con¬
templated by the mind itself through what he
calls a reflex sense, become the objects of love,
or the contrary, according to their nature.
So approved and loved, they constitute virtue
or merit, as distinguished from mere goodness,
of which there are traces in animals who do
not appear to reflect on the state of their own
minds, and who seem, therefore, destitute of
what he elsewhere calls a moral sense. These
statements are, it is true, far too short and
vague. He nowhere inquires into the origin of
the reflex sense. What is a much more material
defect, he makes no attempt to ascertain in what
state of mind it consists. We discover only by
implication, and by the use of the term sense,
that he searches for the fountain of moral senti¬
ments, not in mere reason, where Cudworth
and Clarke had vainly sought for it, but in the
heart, whence the main branch of them assu¬
redly flows. It should never be forgotten, that
we owe to these hints the reception, into ethical
theory, of a moral sense; which, whatever maybe
thought of its origin, or in whatever words it may
be described, must always retain its place in such
theory as a main principle of our moral nature.
His demonstration of the utility of virtue
to the individual, far surpasses all attempts
of the same nature; being founded, not on
a calculation of outward advantages or incon¬
veniences, alike uncertain, precarious, and de¬
grading, but on the unshaken foundation of
the delight, which is of the very essence of so¬
cial affection and virtuous sentiment; on the
dreadful agony inflicted by all malevolent pas¬
sions, upon every soul that harbours the hellish
inmates ; on the all-important truth, that to love
is to be happy, and to hate is to be miserable,—
that affection is its own reward, and ill-will its
own punishment; or, as it has been more simply
and more affectingly, as well as with more sa¬
cred authority, taught, that to give is more
blessed than to receive, and that to love one
another is the sum of all human virtue.
The relation of religion to morality, as far as
it can be discovered by human reason, was never
more justly or more beautifully stated.2 If
he represented the mere hope of reward and
dread of punishment as selfish, and therefore
inferior motives to virtue and piety, he distinct¬
ly owns their efficacy in reclaiming from vice,
in rousing from lethargy, and in guarding a
feeble penitence ; in all which he coincides with
illustrious and zealous Christian writers. “ If
by the hope of reward be understood the love
and desire of virtuous enjoyment, or of the very
practice and exercise of virtue in another life;
an expectation or hope of this kind is so far
from being derogatory from virtue, that it is an
evidence of our loving it the more sincerely and
for its own sake.”*
1 “ It is the height of wisdom no doubt to be rightly selfish.” (Charac. I. 121.) The observation seems to be taken
from what Aristotle says of <P/Xaumz: Tov ^sv aya^av QiXuurov tw/xi. (Arist. Ethic, ix. c. viii.) The chapter is admirable, and
the assertion of Aristotle is very capable of a good sense.
2 Characteristics, Inquiry concerning Virtue.
* Ibid.
So Jeremy Taylor : “ He that is grown in grace pursues virtue purely and simply for its own interest. When persons
come to that height of grace, and love God for himself, that is but heaven in another sense.” {Sermon on Growth in Grace.)
So before him the once celebrated Mr John Smith of Cambridge : “The happiness which good men shall partake is not
distinct from their godlike nature. Happiness and holiness are but two several notions of one thing. Hell is rather a
DISSERTATION SECOND.
351
FENEI.ON"
As the last question, though strictly speak¬
ing theological, is yet in truth dependent on
the more general question, which relates to the
reality of disinterested affections in human na¬
ture, it seems not foreign from the present pur¬
pose to give a short account of a dispute on the
subject in France, between two of the most emi¬
nent persons of their time ; namely, the contro¬
versy between Fenelon and JBossuet, concerning
the possibility of men being influenced by the
pure and disinterested love of God. Never were
two great men more unlike. Fenelon in his
writings exhibits more of the qualities which pre¬
dispose to religious feelings, than any other
equally conspicuous person;—a mind so pure as
steadily to contemplate supreme excellence; a
heart capable of being touched and affected by
the contemplation; a gentle and modest spirit,
not elated by the privilege, but seeing its own
want of worth as it came nearer to such bright¬
ness, and disposed to treat with compassionate
forbearance those errors in others, of which it
felt a humbling consciousness. Bossuet was ra¬
ther a great minister in the ecclesiastical com¬
monwealth; employing knowledge, eloquence,
argument, the energy of his character, the in¬
fluence, and even the authority of his station, to
vanquish opponents, to extirpate revolters, and,
sometimes with a patrician firmness, to with¬
stand the dictatorial encroachment of the Roman
Pontiff on the spiritual aristocracy of France.
Fenelon had been appointed tutor to the Duke
of Burgundy. He had all the qualities which
fit a man to be the preceptor of a prince, and
-BOSSUET.*
which most disable him to get or to keep the
office. Even birth, and urbanity, and accom¬
plishment, and vivacity, were an insufficient
atonement for his genius and virtue. Louis
XIV. distrusted so fine a spirit, and appears to
have early suspected, that a fancy moved by
such benevolence might imagine examples for
his grandson which the world would consider as
a satire on his own reign. Madame de Main-
tenon, indeed, favoured him; but he was gene¬
rally believed to have forfeited her good graces
by discouraging her projects for at least a near¬
er approach to a seat on the throne. He offend¬
ed her by obeying her commands, in laying be¬
fore her an account of her faults, and some of
those of her royal husband, which was probably
the more painfully felt for its mildness, justice,
and refined observation.5 An opportunity for
driving such an intruder from a court presented
itself somewhat strangely, in the form of a subtile
controversy on one of the most abstruse ques¬
tions of metaphysical theology. Molinos, a Spa¬
nish priest, reviving and perhaps exaggerating
the maxims of the ancient Mystics, had recently
taught, that Christian perfection consisted in the
pure love of God, without hope of reward or fear
of punishment. This offence he expiated by
seven years’ imprisonment in the dungeons of
the Roman Inquisition. His opinions were em¬
braced by Madame Guyon, a pious French lady
of strong feeling and active imagination, who
appears to have expressed them in a hyperboli¬
cal language, not infrequent in devotional exer¬
cises, especially in those of otherwise amiable
nature than a place, and heaven canrfot be so well defined by anything without us, as by something within us.” (Select
Discourses, 2d edit. Cambridge, 1673.) v
In accordance with these old authorities is the recent language of a most ingenious as well as benevolent and pious wri-
ter. “ ihe holiness of heaven is still more attractive to the Christian than its happiness. The desire of doing that which
is right for its own sake is a part of his desire after heaven.” (Unconditional Freeness of the Gospel, by T. Erskive Esq.
p. 32, 33. Edinb. 1828.) j r ■> j , r
See also the Appendix to Ward’s o///ran/.More, 247-271. This account of that ingenious and amiable philoso¬
pher (Bond. 1710) contains an interesting view of his opinions, and many beautiful passages of his writings, but un-
rortunately very few particulars of the man. His letters on Disinterested Piety, (see the Appendix to Mr Ward’s work)
ms boundless charity, his zeal for the utmost toleration, and his hope of general improvement from “ a pacific and per¬
spicacious posterity,” place him high in the small number of true philosophers who, in their estimate of men, value dis¬
positions more than opinions, and in their search for good, more often look forward than backward.
1 Born in 1651; died in 1715.
2 Born in 1627 ; died in 1704.
* Bausset, Histoire de Fenelon, I. 252.
352
preliminary dissertations.
persons of her sex and character. In the fer¬
vour of her zeal, she disregarded the usages of
the world and the decorums imposed on females.
She left her family, took a part in public con¬
ferences, and assumed an independence scarcely
reconcilable with the more ordinary and more
pleasing virtues of women. Her pious effusions
were examined with the rigour which might he
exercised on theological propositions. She was
falsely charged by Harlay, the dissolute arch¬
bishop of Paris, with personal licentiousness.
For these crimes she was dragged from convent
to convent, imprisoned for years in the Bastile,
and, as an act of mercy, confined during the lat¬
ter years of her life to a provincial town, as a
prison at large. A piety thus pure and disin¬
terested could not fail to please Fenelon. He
published a work in justification of Madame
Guyon’s character, and in explanation of the
degree in which he agreed with her. Bossuet,
the oracle and champion of the church, took up
arms against him. It would he painful to sup¬
pose that a man of so great powers was actuated
by mean jealousy, and it is needless. The union
of zeal for opinion with the pride of author¬
ity, is apt to give sternness to the administra¬
tion of controversial bishops; to say nothing of
the haughty and inflexible character of Bossuet
himself. He could not brook the independence
of him who was hitherto so docile a scholar and
so gentle a friend. He was jealous of novelties,
and dreaded a fervour of piety likely to he un¬
governable, and perhaps to excite movements ot
which no man could foresee the issue. It must
be allowed that he had reason to he displeased
with the indiscretion and turbulence of the in¬
novators, and might apprehend that, in preach¬
ing motives to virtue and religion which he
thought, unattainable, the coarser hut surer
foundations of common morality might be
loosened. A controversy ensued, in which he
employed the utmost violence of polemical or
factious contest. Fenelon replied with brilliant
guccess, and submitted his hook to the judg¬
ment of Rome. After a long examination, the
commission of ten Cardinals appointed to ex¬
amine it were equally divided, and he seemed
in consequence about to he acquitted. But
Bossuet had in the mean time easily gained
Louis XIV. Madame de Maintenon betrayed
Fenelon’s confidential correspondence; and he
was banished to his diocese, and deprived of his
pensions and official apartments in the palace.
Louis XIV. regarded the slightest differences
from the authorities of the French church as re¬
bellion against himself. Though endowed with
much natural good sense, he was too grossly
ignorant to be made to comprehend one of the
terms of the question in dispute. He did not,
however, scruple to urge the Pope to the con¬
demnation of Fenelon. Innocent XII. (Pigna-
telli) an aged and pacific Pontiff, was desirous
of avoiding such harsh measures. He said that
“ the archbishop of Cambray might have erred
from excess in the love of God, but the bishop
of Meaux had sinned by a defect of the love of
his neighbour.”1 But he was compelled to con¬
demn a series of propositions, of which the first
was, “ there is an habitual state of love to God,
which is pure from every motive of personal
interest, and in which neither the fear of punish¬
ment nor the hope of reward has any part.”2
Fenelon read the bull which condemned him in
his own cathedral, and professed as humble a
submission as the lowest of his flock. In some
of the writings of his advanced years, which have
been recently published, we observe with regret
that, when wearied out by his exile, ambitious to
regain a place at court through the Jesuits, or
prejudiced against the Calvinising doctrines of
the Jansenists, the strongest anti-papal party
among Catholics, or somewhat detached from a
cause of which his great antagonist had been the
victorious leader, he made concessions to the abso¬
lute monarchy of Rome, which did not become
a luminary of the Galilean church.3
Bossuet, in his writings on this occasion, be¬
sides tradition and authorities, relied mainly on
the supposed principle of philosophy, that man
must desire his own happiness, and cannot de-
1 Bausset, Histoire de Fenelon, II. 220, note.
» CEuvres de Bossuet, VIII. 308. Liege, 1767, 8vo.
* De Summi Pontificis Auctoritate Dissertatio: (Euvres de Fenelon, tome ii.
Versailles, 1820.
DISSERTATION SECOND.
353
sire anything else, otherwise than as a means to¬
wards it; which renders the controversy an inci¬
dent in the history of Ethics. It is immediately
connected with the preceding part of this Dis¬
sertation, by the almost literal coincidence be¬
tween Bossuet’s foremost objection to the dis¬
interested piety contended for by Fenelon, and
the fundamental position of a very ingenious
and once noted divine of the English church,
in his attack on the disinterested affections,
believed by Shaftesbury to be a part of human
nature.1 2
LEIBNITZ.
There is a singular contrast between the form
of Leibnitz’s writings and the character of his
mind. The latter was systematical, even to ex¬
cess. It was the vice of his prodigious intellect,
on every subject of science where it was not
bound by geometrical chains, to confine his view
to those most general principles, so well called
by Bacon “ merely notionalwhich render it,
indeed, easy to build a system, but, only because
they may be alike adapted to every state of ap¬
pearances, and become thereby really inappli¬
cable to any. Though his genius was thus
naturally turned to system, his writings were,
generally, occasional and miscellaneous. The
fragments of his doctrines are scattered in Re¬
views ; or over a voluminous Literary Correspond¬
ence; or in the Prefaces and Introductions to
those compilations to which this great philoso¬
pher was obliged by his situation to descend.
This defective and disorderly mode of publica¬
tion arose partly from the jars between business
and study, inevitable in his course of life; but
probably yet more from the nature of his system,
which, while it widely deviates from the most
general principles of former philosophers, is
ready to embrace their particular doctrines under
its own generalities, and thus to reconcile them
to each other, as well as to accommodate itself
to popular or established opinions, and compro¬
mise with them, according to his favourite and
oft-repeated maxim, “ that most received doc¬
trines are capable of a good sense ;”3 by which last
words our philosopher meant a sense reconcil¬
able with his own principles. Partial and oc¬
casional exhibitions of these principles suited
better that constant negotiation with opinions,
establishments, and prejudices, to which extreme
generalities are well adapted, than a full and
methodical statement of the whole at once. It
is the lot of every philosopher who attempts to
make his principles extremely flexible, that they
become like those tools which bend so easily as
to penetrate nothing. Yet his manner of publi¬
cation perhaps led him to those wide intuitions,
as comprehensive as those of Bacon, of which he
expressed the result as briefly and pithily as
Hobbes. The fragment which contains his ethi¬
cal principles is the Preface to a collection of
documents illustrative of international law, pub¬
lished at Hanover in 1693 ;4 to which he often
referred as his standard afterwards, especially
when he speaks of Lord Shaftesbury, or of the
controversy between the two great theologi¬
ans of France. “ Right,” says he, “ is moral
power; obligation moral necessity. By moral,
I understand what with a good man prevails as
much as if it were physical. A good man is he
who loves all men as far as reason allows. Justice
1 “ Haec est natura voluntatis humanae, ut et beatitudinem, et ea quorum necessaria connexio cum beatitudine clare
intelligitur, necessario appetat Nullus est actus ad quern revera non impellimur motivo beatitudinis, explicite vel
implicates" meaning by the latter that it may be concealed from ourselves, as he says, for a short time, by a nearer object.
(CEuvres de Bossuet, VIII. 80.) “ The only motive by which individuals can be induced to the practice of virtue, must be
the feeling or the prospect of private happiness.” (Brown’s Essays on the Characteristics, p. 159. Lond. 1752.) It must,
however, be owned, that the selfishness of the Warburtonian is more rigid; making no provision for the object of one’s
own happiness slipping out of view for a moment. It is due to the vejy ingenious author of this forgotten book to add,
that it is full of praise of his adversary, which, though just, was in the answerer generous ; and that it contains an assertion
of the unbounded right of public discussion, unusual even at the tolerant period of its appearance.
2 Born in 1648 ; died in 1716.
* Nouveaux Essais sur VEntendement Humain, liv. i. chap. ii. p. 57- These Essays, which form the greater part of the
publication entitled CEuvres Philosophxques, edited by Raspe, Amst. et Leipz. 1765, are not included in Dutens’s edition of
Leibnitz’s works.
4 Codex Juris Gentium Diplomaticus. Hanov. 1695.
DISS. II. 2 Y
354 preliminary dissertations.
is the benevolence of a wise man. To love is to
be pleased with the happiness of another ; or, in
other words, to convert the happiness of another into
a part of one's own. Hence is explained the
possibility of a disinterested love. When we are
pleased with the happiness of any being, his
happiness becomes one of our enjoyments. Wis¬
dom is the science of happiness.’ 1
REMARKS.
It is apparent from the above passage, that
Leibnitz had touched the truth on the subject of
disinterested affection ; and that he was more
near clinging to it than any modern philosopher,
except Lord Shaftesbury. It is evident, how¬
ever, from the latter part of it, that, like Shaftes¬
bury, he shrunk from his own just conception ;
under the influence of that most ancient and far-
spread prejudice of the schools, which assumed
that such an abstraction as Happiness could be
the object of love, and that the desire of so faint,
distant, and refined an object, was the first
principle of all moral nature, of which every
other desire was only a modification or a fruit.
Both he and Shaftesbury, however, when they
relapsed into the selfish system, embraced it in
its most refined form; considering the benevo¬
lent affections as valuable parts of our own hap¬
piness, not in consequence of any of their effects
or extrinsic advantages, but of that intrinsic de¬
lightfulness which was inherent in their very
essence. But Leibnitz considered this refined
pleasure as the object in the view of the bene¬
volent man; an absurdity, or rather a contra¬
diction, which, at least in the Inquiry concerning
Virtue, Shaftesbury avoids. It will be seen from
Leibnitz’s limitation, taken together with his
definition of Wisdom, that he regarded the dis¬
tinction of the moral sentiments from the social
affections, and the just subordination of the
latter, as entirely founded on the tendency of
general happiness to increase that of the agent,
not merely as being real, but as being present
to the agent’s mind when he acts. In a subse¬
quent passage he lowers his tone not a little.
' As for the sacrifice of life, or the endurance
of the greatest pain for others, these things are
rather generously enjoined than solidly demon¬
strated by philosophers. For honour, glory, and
self-congratulation, to which they appeal under
the name of Virtue, are indeed mental plea¬
sures, and of a high degree, but not to all, nor
outweighing every bitterness of suffering; since
all cannot imagine them with equal vivacity,
and that power is little possessed by those whom
neither education, nor situation, nor the doc¬
trines of religion or philosophy, have taught to
value mental gratifications.” 8 He concludes very
truly, that morality is completed by a belief of
moral government. But the Inquiry concerning
Virtue had reached that conclusion by a better
road. It entirely escaped his sagacity, as it has
that of nearly all other moralists, that the co¬
incidence of morality with well-understood in¬
terest in our outward actions, is very far from
being the most important part of the question;
for these actions flow from habitual dispositions,
from affections and sensibilities, which deter¬
mine their nature. There may be, and there
are many immoral acts, which, in the sense
in which words are commonly used, are advan¬
tageous to the actor. But the whole sagacity
and ingenuity of the world may be safely chal¬
lenged to point out a case in which virtuous
dispositions, habits, and feelings, are not con¬
ducive in the highest degree to the happiness of
the individual; or to maintain that he is not the
happiest, whose moral sentiments and affections
are such as to prevent the possibility of the
prospect of advantage through unlawful means
from presenting itself to his mind. It would
indeed have been impossible to prove to Rega¬
ins that it was his interest to return to a death
of torture in Africa. But what if the proof
had been easy ? The most thorough conviction
on such a point would not have enabled him to
set this example, if he had not been supported
by his own integrity and generosity, by love of
his country, and reverence for his pledged faith.
What could the conviction add to that greatness
of soul, and to these glorious attributes ? With
such virtues he could not act otherwise than he
1 See Notes and Illustrations, note N.
* Ibid, note N.
DISSERTATION SECOND.
355
did. Would a father affectionately interested
in a son’s happiness, of very lukewarm feel¬
ings of morality, but of good sense enough to
weigh gratifications and sufferings exactly, he
really desirous that his son should have these
virtues in a less degree than Regulus, merely
because they might expose him to the fate which
Regulus chose ? On the coldest calculation he
would surely perceive, that the high and glow¬
ing feelings of such a mind during life, altogether
throw into shade a few hours of agony in leaving
it. And, if he himself were so unfortunate that
no more generous sentiment arose in his mind to
silence such calculations, would it not be a re¬
proach to his understanding not to discover,
that though in one case out of millions such a
character might lead a Regulus to torture, yet, in
the common course of nature, it is the source
not only of happiness in life, hut of quiet and
honour in death. A case so extreme as that of
Regulus will not perplex, if we hear in mind,
that though we cannot prove the act of heroic
virtue to be conducive to the interest of the
hero, yet we may perceive at once, that nothing
is so conducive to his interest as to have a mind
so formed that it could not shrink from it, hut
must rather embrace it with gladness and tri¬
umph. Men of vigorous health are said some¬
times to suffer most in a pestilence. No man
was ever so absurd as for that reason to wisli
that he were more infirm. The distemper might
return once in a century. If he were then alive,
he might escape it; and even if he fell, the
balance of advantage would he in most cases
greatly on the side of robust health. In esti¬
mating beforehand the value of a strong bodily
frame, a man of sense would throw the small
chance of a rare and short evil entirely out of
the account. So must the coldest and most self¬
ish moral calculator, who, if he he sagacious and
exact, must pronounce, that the inconveniences
to which a man may he sometimes exposed by a
pure and sound mind, are no reasons for regret¬
ting that we do not escape them by possessing
minds more enfeebled and distempered. Other
occasions will call our attention, in the sequel, to
this important part of the subject. But the great
name of Leibnitz seemed to require that his de¬
grading statement should not be cited without
warning the reader against its egregious fallacy.
MALEBRANCHE.1 * * *
This ingenious philosopher and beautiful
writer is the only celebrated Cartesian who has
professedly handled the Theory of Morals.8 His
theory has in some points of view a conformity
to the doctrine of Clarke; while in others it has
given occasion to his English follower Norris5
to say, that if the Quakers understood their
own opinion of the illumination of all men, they
would explain it on the principles of Malehranche.
“ There is,” says he, “ one parent virtue, the
universal virtue, the virtue which renders us
just and perfect, the virtue which will one day
render us happy. It is the only virtue. It is
the love of the universal order, as it eternally
existed in the Divine reason, where every creat¬
ed reason contemplates it. This order is com¬
posed of practical as well as speculative truth.
Reason perceives the moral superiority of one
being over another, as immediately as the equal¬
ity of the radii of the same circle. The rela¬
tive perfection of beings is that part of the im¬
movable order to which men must conform
their minds and their conduct. The love of
order is the whole of virtue, and conformity to
order constitutes the morality of actions.” It
is not difficult to discover, that in spite of the
singular skill employed in weaving this web, it
answers no other purpose than that of hiding
the whole difficulty. The love of universal or¬
der, says Malehranche, requires that we should
value an animal more than a stone, because it
is more valuable ; and love God infinitely more
than man, because he is infinitely better. But
without presupposing the reality of moral dis-
1 Born in 1638 ; died in 1715.
* Traite de Morale. Rotterdam, 1684.
J Author of the Theory of the Ideal World, who well copied, though he did not equal the clearness and choice of expres¬
sion which belonged to his master.
356
PRELIMINARY DISSERTATIONS.
tinctions, and the power of moral feelings, the
two points to he proved, how can either of
these propositions he evident, or even intel¬
ligible? To say that a love of the eternal
order will produce the love and practice of
every virtue, is an assertion untenable unless
we take morality for granted, and useless if
we do.
In his work on Morals, all the incidental
and secondary remarks are equally well consid¬
ered and well expressed. The manner in which
he applied his principle to the particulars of
human duty, is excellent. He is perhaps the
first philosopher who has precisely laid down
and rigidly adhered to the great principle, that
virtue consists in pure intentions and dispositions
of mind, without which, actions, however con-
JONATHAN
This remarkable man, the metaphysician of
America, was formed among the Calvinists of
New England, when their stern doctrine retained
its rigorous authority.1 2 * 4 His power of subtile ar¬
gument, perhaps unmatched, certainly unsur¬
passed among men, was joined, as in some of
the ancient Mystics, with a character which
raised his piety to fervour. He embraced their
doctrine, probably without knowing it to he
theirs. “ True religion,” says he, “ in a great
measure consists in holy affections. A love
of divine things, for the beauty and sweetness
of their moral excellency, is the spring of all
holy affections.”3 Had he suffered this noble
principle to take the right road to all its fair
consequences, he would have entirely concurred
with Plato, with Shaftesbury, and Malebranche,
in devotion to “ the first good, first perfect, and
first fair.” But he thought it necessary after¬
wards to limit his doctrine to his own persua¬
sion, by denying that such moral excellence
could he discovered in divine things by those
formable to rules, are not truly moral; a truth
of the highest importance, which, in the theolo¬
gical form, may he said to have been the main
principle of the first Protestant Reformers. The
ground of piety, according to him, is the con¬
formity of the attributes of God to those moral
qualities which we irresistibly love and revere.1
“ Sovereign princes,” says he, “ have no right
to use their authority without reason. Even
God has no such miserable right.”8 His dis¬
tinction between a religious society and an
established church, and his assertion of the
right of the temporal power alone to employ
coercion, are worthy of notice, as instances in
which a Catholic, at once philosophical and or¬
thodox, could thus speak, not only of the na¬
ture of God, hut of the rights of the church.
EDWARDS.*
Christians who did not take the same view with
him of their religion. All others, and some who
hold his doctrines with a more enlarged spirit,
may adopt his principle without any limitation.
His ethical theory is contained in his Disser¬
tation on the Nature of True Virtue; and in
another, On God's Chief End in the Creation,
published in London thirty years after his death.
True virtue, according to him, consists in be¬
nevolence, or love to being “ in general,”
which he afterwards limits to {t intelligent
being,” though sentient would have involved
a more reasonable limitation. This good-will
is felt towards a particular being, first in pro¬
portion to his degree of existence (for, says he,
“ that which is great has more existence, and is
farther from nothing, than that which is little”);
and secondly, in proportion to the degree in
which that particular being feels benevolence to
others. Thus God, having infinitely more ex¬
istence and benevolence than man, ought to he
infinitely more loved; and for the same rea-
1 “ 11 faut aimer 1’Etre infiniment parfait, et non pas un fantome e'pouvantable, un Dieu injuste, absolu, puissant, mais
sans bonte et sans sagesse. S’il y avoit un tel Dieu, le vrai Dieu nous defendroit de 1’adorer et de I’aimer. II y a peut-etre
plus de danger d’offenser Dieu lorsqu’on lui donne une forme si horrible, que de mepriser ce fantome.” (Traite de Morale,
chap, viii.)
2 Ibid. chap. xxii.
* Born in 1703, at Windsor in Connecticut; died in 1758, at Princeton in New Jersey.
* Notes and Illustrations, note O.
* Edwards on Religious Affections, p. 4, 187. Lond. 1796.
DISSERTATION SECOND.
357
son, God must love himself infinitely more
than he does all other beings.1 2 * He can act
only from regard to himself, and his end in
creation can only he to manifest his whole
nature, which is called acting for his own
glory.
As far as Edwards confines himself to creat¬
ed beings, and while his theory is perfectly in¬
telligible, it coincides with that of universal
benevolence, hereafter to he considered. The
term being is a mere encumbrance, which serves
indeed to give it a mysterious outside, hut
brings with it from the schools nothing ex¬
cept their obscurity. He was betrayed into it
by the cloak which it threw over his really un¬
meaning assertion or assumption, that there are
degrees of existence ; without which that part of
his system which relates to the Deity would have
appeared to he as baseless as it really is. When
we try such a phrase by applying it to matters
within the sphere of our experience, we see that
it means nothing hut degrees of certain faculties
and powers. But the very application of the
term being to all things, shows that the least
perfect has as much being as the most perfect;
or rather that there can he no difference, so far
as that word is concerned, between two things
to which it is alike applicable. The justness of
the compound proportion on which human vir¬
tue is made to depend, is capable of being tried
by an easy test. If we suppose the greatest of
evil spirits to have a hundred times the had
passions of Marcus Aurelius, and at the same
time a hundred times his faculties, or, in Ed¬
wards’s language, a hundred times his quantity
of being, it follows from this moral theory, that
we ought to esteem and love the devil exactly
in the same degree as we esteem and love Mar¬
cus Aurelius.
The chief circumstance which justifies so
much being said on the last two writers, is their
concurrence in a point towards which Ethical
Philosophy had been slowly approaching, from
the time of the controversies raised up by Hobbes.
They both indicate the increase of this tendency,
by introducing an element into their theory, for¬
eign from those cold systems of ethical abstrac¬
tion, with which they continued in other respects
to have much in common. Malebranche makes
virtue consist in the love of order, Edwards in
the love of being. In this language we perceive
a step beyond the representation of Clarke, which
made it a conformity to the relations of things;
hut a step which cannot he made without pass¬
ing into a new province;—without confessing,
by the use of the word love, that not only per¬
ception and reason, hut emotion and sentiment,
are among the fundamental principles of morals.
They still, however, were so wedded to scholas¬
tic prejudice, as to choose two of the most aerial
abstractions which can he introduced into argu¬
ment,—being and order,—to he the objects of
those strong active feelings which were to govern
the human mind.
BUFFIER.*
The same strange disposition to fix on ab¬
stractions as the objects of our primitive feelings,
and the end sought by our warmest desires,
manifests itself in the ingenious writer with
whom this part of the Dissertation closes, under
a form of less dignity than that which it assumes
in the hands of Malebranche and Clarke. Buf-
fier, the only Jesuit whose name has a place in
the history of Abstract Philosophy, has no pecu¬
liar opinions which would have required any
mention of him as a moralist, were it not for the
just reputation of his treatise on First Truths,
with which Dr Reid so remarkably, though un¬
aware of its existence, coincides, even in the
misapplication of so practical a term as com¬
mon sense to denote the faculty which recog¬
nises the truth of First Principles. His phi¬
losophical writings5 are remarkable for that
1 The coincidence of Malebranche with this part of Edwards, is remarkable. Speaking of the Supreme Being, he says,
“ II s'aime invinciblement.” He adds another more startling expression, “ Certainement Dieu ne pent agir que pour lui-
meme: il n’a point d’autre motif que son amour propre.” (Traite de Morale, chap, xvii )
2 Born in 1661; died in 1737-
* Cours de Sciences. Paris, 1732, folio.
358
PRELIMINARY DISSERTATIONS.
perfect clearness of expression, which, since the
great examples of Descartes and Pascal, has
been so generally diffused as to have become
one of the enviable peculiarities of French philo¬
sophical style, and almost of the French lan¬
guage. His ethical doctrine is that most common¬
ly received among philosophers, from Aristotle
to Paley and Bentham : “ I desire to be happy;
but as I live with other men, I cannot be happy
without consulting their happinessa propo¬
sition perfectly true indeed, but far too narrow,
as inferring, that in the most benevolent acts
a man must pursue only his own interest, from
the fact that the practice of benevolence does
increase his happiness, and that because a vir¬
tuous mind is likely to be the happiest, our ob¬
servation of that property of virtue is the cause
of our love and reverence for it.
SECTION VI.
Foundations of a more just Theory of Ethics.
BUTLER—HUTCHESON—BERKELEY—HUME—SMITH—PRICE—HARTLEY—TUCKER—
PALEY—BENTHAM—STEWART—BROWN.
From the beginning of ethical controversy to
the eighteenth century, it thus appears, that the
care of the individual for himself, and his re¬
gard for the things which preserve self, were
thought to form the first, and, in the opinion of
most, the earliest of all the principles which
prompt men and other animals to activity; that
nearly all philosophers regarded the appetites
and desires, which look only to self-gratification,
as modifications of this primary principle of self-
love; and that a very numerous body consid¬
ered even the social affections themselves as
nothing more than the produce of a more la¬
tent and subtile operation of the desire of in¬
terest, and of the pursuit of pleasure. It is
true, they often spoke otherwise; but it was
rather from the looseness and fluctuation of
their language, than from distrust in their doc¬
trine. It is true, also, that perhaps all repre¬
sented the gratifications of virtue as more un¬
mingled, more secure, more frequent, and more
lasting, than other pleasures; without which
they could neither have retained a hold on the
assent of mankind, nor reconciled the principles
of their systems with the testimony of their
hearts. We have seen how some began to be
roused from a lazy acquiescence in this an¬
cient hypothesis, by the monstrous consequences
which Hobbes had legitimately deduced from
it. A few, of pure minds and great intellect,
laboured to render morality disinterested, by
tracing it to reason as its source; without con¬
sidering that reason, elevated indeed far above
interest, is also separated by an impassable
gulf, from feeling, affection, and passion. At
length it was perceived by more th,un one, that
through whatever length of reasoning the mind
may pass in its advances towards action, there
is placed at the end of any avenue through
which it can advance, some principle wholly
unlike mere reason,—some emotion or sentiment
which must be touched, before the springs of
will and action can be set in motion. Had Lord
Shaftesbury steadily, adhered to his own prin¬
ciples—had Leibnitz not recoiled from his state¬
ment—the truth might have been regarded as
promulged, though not unfolded. The writings of
both prove, atleast to us, enlightened as we are by
what followed, that they were skilful in sound¬
ing, and that their lead had touched the bottom.
But it was reserved for another moral philosopher
to determine this hitherto unfathomed depth.1
1 The doctrine of the Stoics is thus put by Cicero into the mouth of Cato: “ Placet his, inquit, quorum ratio mihi
probatur, simul atque natum sit animal, (hinc enim est ordiendum) ipsum sibi conciliari et commendari ad se conservandum.
DISSERTATION SECOND.
359
BUTLER.1
Butler, who was the son of a Presbyterian
trader, early gave such promise, as to induce his
father to fit him, by a proper education, for being
a minister of that persuasion. He was edu¬
cated at one of their seminaries under Mr Jones
of Gloucester, where Seeker, afterwards arch¬
bishop of Canterbury, was his fellow-student.
Though many of the dissenters had then begun
to relinquish Calvinism, the uniform effect of
that doctrine, in disposing its adherents to meta¬
physical speculation, long survived the opinions
which caused it, and cannot be doubted to have
influenced the mind of Butler. When a student
at the academy of Gloucester, he wrote private
letters to Hr Clarke on his celebrated Demonstra¬
tion, suggesting objections which were really in¬
superable, and which are marked by an acute¬
ness which neither himself nor any other ever
surpassed. Clarke, whose heart was as well
schooled as his head, published the letters, with
his own answers, in the next edition of his work;
and, by his good offices with his friend and
follower, Sir Joseph Jekyll, obtained for the
young philosopher an early opportunity of mak¬
ing his abilities and opinions known, by the ap¬
pointment of preacher at the Chapel of the
Master of the Rolls. He was afterwards raised
to one of the highest seats on the Episcopal
bench, through the philosophical taste of Queen
Caroline, and her influence over the mind of her
husband, which continued long after her death.
“ He was wafted,” says Horace Walpole, “ to
the see of Durham, on a cloud of Metaphy¬
sics.”2 Even in the fourteenth year of his
widowhood, George II. was desirous of inserting
the name of the Queen’s metaphysical favourite
in the Regency Bill of seventeen hundred and
fifty-one.
His great work on the Analogy of Religion to
the Course of Nature, though only a commentary
on the singularly original and pregnant passage
of Origen, which is so honestly prefixed to it as
a motto, is, notwithstanding, the most original
and profound work extant in any language on
the Philosophy of Religion. It is entirely beyond
our present scope. His ethical discussions are
contained in those deep and sometimes dark Dis¬
sertations which he preached at the Chapel of
the Rolls, and afterwards published under the
.name of Sermons, while he was yet fresh from
the schools, and full of that courage with which
youth often delights to exercise its strength in
abstract reasoning, and to push its faculties into
the recesses of abstruse speculation. But his
youth was that of a sober and mature mind,
early taught by nature to discern the boundaries
of knowledge, and to abstain from fruitless ef¬
forts to reach inaccessible ground. In these
sermons,5 he has taught truths more capable of
being exactly distinguished from the doctrines
of his predecessors, more satisfactorily establish¬
ed by him, more comprehensively applied to par¬
ticulars, more rationally connected with each
other, and therefore more worthy of the name
of discovery, than any with which we are ac¬
quainted; if we ought not, with some hesita¬
tion, to except the first steps of the Grecian phi¬
losophers towards a Theory of Morals. It is a
peculiar hardship, that the extreme ambiguity of
language, an obstacle which it is one of the
chief merits of an ethical philosopher to vanquish,
is one of the circumstances which prevent men
et ad suum statum, et ad ea quae conservantia sunt ejus status diligenda; alienari autem ab interitu, iisque rebus quae in-
teritum videantur afFerre. Id ita esse sic probant, quod, antequam voluptas aut dolor attigerit, salutaria appetant parvi,
aspernenturque contraria. Quod non fieret, nisi statum suum diligerent, interitum timerent. Fieri autem non posset ut ap-
peterent aliquid, nisi sensum haberent sui, eoque se et sua diligerent. Ex Quo inteljligi debet, principium ductum esse a
se diligendi.” (De Finibus, lib. iii. cap. v.) We are told that diligendo is the reading of an ancient MS. Perhaps the
omission of ‘ a’ would be the easiest and most reasonable emendation.
The above passage is perhaps the fullest and plainest statement of the doctrines prevalent till the time of Butler.
1 Born in 1692; died in 1752.
2 Walpole’s Memoirs.
* See Sermons i. ii. and iii. On Human Nature; v. On Compassion ; viii. On Resentment; ix. On Forgiveness; xi. and
xii. On the Love of our Neighbour; and xiii. On the Love of God; together with the excellent Preface.
360
PRELIMINARY DISSERTATIONS.
from seeing the justice of applying to him so
ambitious a term as discovery. Butler owed
more to Lord Shaftesbury than to all other wri¬
ters besides. He is just and generous towards
that philosopher; yet, whoever carefully com¬
pares their writings, will without difficulty dis ¬
tinguish the two builders, and the larger as well
as more regular and laboured part of the edifice,
which is due to Butler.
Mankind have various principles of action;
some leading directly to the private good, some
immediately to the good of the community.
But the private desires are not self-love, or any
form of it; for self-love is the desire of a man’s
own happiness, whereas the object of an appe¬
tite or passion is some outward thing. Self-love
seeks things as means of happiness; the private
appetites seek things, not as means, but as ends.
A man eats from hunger, and drinks from
thirst; and though he knows that these acts
are necessary to life, that knowledge is not the
motive of his conduct. No gratification can in¬
deed he imagined without a previous desire.
If all the particular desires did not exist inde¬
pendently, self-love would have no object to
employ itself about; for there would he no
happiness, which, by the very supposition of
the opponents, is made up of the gratifications
of various desires. No pursuit could be selfish
or interested, if there were not satisfactions first
gained by appetites which seek their own out¬
ward objects without regard to self; which sa¬
tisfactions compose the mass which is called a
man’s interest.
In contending, therefore, that the benevolent
affections are disinterested, no more is claimed
for them than must he granted to mere animal
appetites and to malevolent passions. Each of
these principles alike seeks its own object, for
the sake simply of obtaining it. Pleasure is
the result of the attainment, hut no separate
part of the aim of the agent. The desire that
another person may he gratified, seeks that out¬
ward object alone, according to the general
course of human desire. Resentment is as dis¬
interested as gratitude or pity, hut not more so.
Hunger or thirst may be, as much as the purest
benevolence, at variance with self-love. A re¬
gard to our own general happiness is not a vice,
hut in itself an excellent quality. It were well
if it prevailed more generally over craving and
short-sighted appetites. The weakness of the
social affections, and the strength of the private
desires, properly constitute selfishness; a vice
utterly at variance with the happiness of him
who harbours it, and as such, condemned by
self-love. There are as few who attain the
greatest satisfaction to themselves, as who do
the greatest good to others. It is absurd to say
with some, that the pleasure of benevolence is
selfish because it is felt by self. Understand¬
ing and reasoning are acts of self, for no man
can think by proxy; hut no one ever called
them selfish. Why? Evidently because they
do not regard self. Precisely the same reason
applies to benevolence. Such an argument is a
gross confusion of self, as it is a subject of feel¬
ing or thought, with self considered as the object
of either. It is no more just to refer the private
appetites to self-love because they commonly
promote happiness, than it would he to refer
them to self-hatred in those frequent cases
where their gratification obstructs it.
But, besides the private or public desires, and
besides the calm regard to our own general wel¬
fare, there is a principle in man, in its nature
supreme over all others. This natural supre¬
macy belongs to the faculty which surveys, ap¬
proves, or disapproves the several affections of
our minds and actions of our lives. As self-
love is superior to the private passions, so con¬
science is superior to the whole of man. Pas¬
sion implies nothing hut an inclination to follow
it; and in that respect passions differ only in
force. But no notion can be formed of the
principle of reflection, or conscience, which does
not comprehend judgment, direction, superin¬
tendency. Authority over all other principles
of action is a constituent part of the idea of con¬
science, and cannot he separated from it. Had
it strength as it has right, it would govern the
world. The passions would have their power
hut according to their nature, which is to he
subject to conscience. Hence we may under¬
stand the purpose at which the ancients, perhaps
confusedly, aimed, when they laid it down,
that virtue consisted in following nature. It is
neither easy, nor, for the main object of the
DISSERTATION SECOND.
361
moralist, important, to render the doctrines of
the ancients by modern language. If Butler re¬
turns to this phrase too often, it was rather from
the remains of undistinguishing reverence for
antiquity, than because he could deem its em¬
ployment important to his own opinions.
The tie which holds together Religion and
Morality, is, in the system of Butler, somewhat
different from the common representations, but
not less close. Conscience, or the faculty of ap¬
proving or disapproving, necessarily constitutes
the bond of union. Setting out from the belief
of Theism, and combining it, as he had entitled
himself to do, with the reality of conscience, he
could not avoid discovering, that the being who
possessed the highest moral qualities, is the ob¬
ject of the highest moral affections. He con¬
templates the Deity through the moral nature
of man. In the case of a being who is to be
perfectly loved, “ goodness must be the simple
actuating principle within him; this being the
moral quality which is the immediate object of
love.” “ The highest, the adequate object of
this affection, is perfect goodness; which, there¬
fore, we are to love with all our heart, with all
our soul, and with all our strength.” “ We
should refer ourselves implicitly to him, and
cast ourselves entirely upon him. The whole at¬
tention of life should be to obey his commands.”1
Moral distinctions are thus presupposed before
a step can be made towards religion: virtue
leads to piety; God is to be loved, because good¬
ness is the object of love; and it is only after
the mind rises through human morality to di¬
vine perfection, that all the virtues and duties
are seen to hang from the throne of God.
REMARKS.
There do not appear to be any errors in the
ethical principles of Butler. The following
remarks are intended to point out some defects
in his scheme; and even that attempt is made
with the unfeigned humility of one who rejoices
in an opportunity of doing justice to that part of
the writings of a great philosopher which has
not been so clearly understood, nor so justly
estimated by the generality, as his other works.
1. It is a considerable defect, though perhaps
unavoidable in a sermon, that he omits all in¬
quiry into the nature and origin of the private
appetites, which first appear in human nature.
It is implied, but it is not expressed in his rea¬
sonings, that there is a time before the child can
be called selfish, any more than social, when
these appetites seem as it were separately to
pursue their distinct objects, long antecedent to
the state of mind in which all their gratifica¬
tions are regarded as forming the mass called
happiness. It is hence that they are likened to
instincts, in contradiction to their subsequent
distinction, which requires reason and experi¬
ence.2
2. Butler shows admirably well, that unless
there were principles of action independent of
self, there could be no pleasures and no happi¬
ness for self-love to watch over. A step farther
would have led him to perceive, that self-love is
altogether a secondary formation; the result of
the joint operation of reason and habit upon the
primary principles. It could not have existed
without presupposing original appetites and or¬
ganic gratifications. Had he considered this
part of the subject, he would have strengthened
his case by showing that self-love is as truly a
derived principle, not only as any of the social
affections, but as any of the most confessedly ac¬
quired passions. It would appear clear, that as
self-love is not divested of its self-regarding
character by considering it as acquired, so the
social affections do not lose any part of their dis¬
interested character, if they be considered as
formed from simpler elements. Nothing would
more tend to root out the old prejudice which
treats a regard to self as analogous to a self-evi¬
dent principle, than the proof, that self-love is
itself formed from certain original elements, and
that a living being long subsists before its ap¬
pearance. 3
1 Sermon xiii. On the Love of God.
* The very able work ascribed to Mr Hazlitt, entitled Essay on the Principles of Human Action, Lond. 1805, contains
original views on this subject.
* Compare this statement with the Stoical doctrine explained by Cicero in the book de Finihus, quoted above, of which it
is the direct opposite.
DISS. II. 2 z
362
PRELIMINARY DISSERTATIONS.
3. It must be owned that those parts of Butler’s themselves the end, or last object in view, of any
discour ses which relate to the social affections other desire or aversion. Nothing stands between
are more satisfactory than those which handle the moral sentiments and their object. They
the question concerning the moral sentiments, are, as it were, in contact with the will. It is
It is not that the real existence of the latter is this sort of mental position, if the expression may
not as well made out as that of the former. In he pardoned, that explains, or seems to explain
both cases he occupies the unassailable ground those characteristic properties which true plnlo-
of an appeal to consciousness. All men (even sophers ascribe to them, and which all reflecting
the worst) feel that they have a conscience and men feel to belong to them. Being the only de-
disinterested affections. But he betrays a sense sires, aversions, sentiments, or emotions, which
of the greater vagueness of his notions on this regard dispositions and actions, they neces-
suhject. He falters as he approaches it. He sarily extend to the whole character and conduct.
makes no attempt to determine in what state of Among motives to action, they alone are just-
mind the action of conscience consists. He does ly considered as universal. They may and do
not venture steadily to denote it by a name. He stand between any other practical principle
fluctuates between different appellations, and and its object; while it is absolutely impos-
multiplies the metaphors of authority and com- sible that another shall intercept their con-
mand, without a simple exposition of that mental nection with the will. Be it observed, that
operation which these metaphors should only though many passions prevail over them, no
have illustrated. It commands other principles, other can act beyond its own appointed and li-
But the question recurs, why, or how ? mited sphere; and that the prevalence itself,
Some of his own hints, and some fainter inti- leaving the natural order undisturbed in any
mations of Shaftesbury, might have led him to other part of the mind, is perceived to he a dis-
what appears to he the true solution; which, order, when seen in another man, and felt to he
perhaps from its extreme simplicity, has escaped so by the mind disordered, when the disorder
him and his successors. The truth seems to he, subsides. Conscience may forbid the will to
that the moral sentiments in their mature state, contribute to the gratification of a desire. No
are a class of feelings which have no other object hut desire ever forbids will to obey conscience.
the mental dispositions leading to voluntary action. This result of the peculiar relation of con-
and the voluntary actions which flow from these dis- science to the will, justifies those metaphorical
positions. We are pleased with some disposi- expressions which ascribe to it authority and the
tions and actions, and displeased with others, in right of universal command. It is immutable ; for,
ourselves and our fellows. We desire to culti- by the law which regulates all feelings, it must
vate the dispositions, and to perform the actions, rest on action, which is its object, and beyond
which we contemplate with satisfaction. These which it cannot look; and as it employs no
objects, like all those of human appetite or de- means, it never can he transferred to nearer ob-
sire, are sought for their own sake. The peculi- jects, in the way in which he who first desires
arity of these desires is, that their gratification an object as a means of gratification, may come
requires the use of no means. Nothing (unless it to seek it as his end. Another lemarkahle pecu-
he a volition) is interposed between the desire liarity is bestowed on the moral feelings by the
and the voluntary act. It is impossible, therefore, nature of their object. As the objects of all
that these passions should undergo any change other desires are outward, the satisfaction of
by transfer from the end to the means, as is the them may he frustrated by outward causes,
case with other practical principles. On the other The moral sentiments may always he gratified,
hand, as soon as they are fixed on these ends, because voluntary actions and moral dispositions
they cannot regard any further object. When spring from within. No external circumstance
another passion prevails over them, the end of affects them. Hence their independence. As
the moral faculty is converted into a means of the moral sentiment needs no means, and the de¬
gratification. But volitions and actions are not sire is instantaneously followed by the volition,
DISSERTATION SECOND.
363
it seems to be either that which first suggests
the relation between command and obedience, or
at least that which affords the simplest instance
of it. It is therefore with the most rigorous
precision that authority and universality are
ascribed to them. Their only unfortunate pro¬
perty is their too frequent weakness; but it
is apparent that it is from that circumstance
alone that their failure arises. Thus considered,
the language of Butler concerning conscience,
that, “ had it strength as it has right it would
govern the world,” which may seem to be only
an effusion of generous feeling, proves to be a
just statement of the nature and action of the
highest of human faculties. The union of uni¬
versality, immutability, and independence, with
direct action on the will, which distinguishes
the moral sense from every other part of our
practical nature, renders it scarcely metaphori¬
cal language to ascribe to it unbounded sove¬
reignty and awful authority over the whole of
the world within;—shows that attributes, well
denoted by terms significant of command and
control, are, in fact, inseparable from it, or ra¬
ther constitute its very essence;—justifies those
ancient moralists who represent it as alone se¬
curing, if not forming the moral liberty of man ;
and finally, when religion rises from its roots in
virtuous feeling, it clothes conscience with the
sublime character of representing the divine pu¬
rity and majesty in the human soul. Its title
is not impaired by any number of defeats; for
every defeat necessarily disposes the disinterest¬
ed and dispassionate by-stander to wish that its
force were strengthened: and though it may be
doubted whether, consistently with the present
constitution of human nature, it could he so in¬
vigorated as to be the only motive to action,
yet every such by-stander rejoices at all acces¬
sions to its force; and would own, that man be¬
comes happier, more excellent, more estimable,
more venerable, in proportion as conscience ac¬
quires a power of banishing malevolent passions,
of strongly curbing all the private appetites, of
influencing and guiding the benevolent affections
themselves.
Let it be carefully considered whether the
same observations could be made with truth,
or with plausibility, on any other part or ele¬
ment of the nature of man. They are entirely
independent of the question, whether conscience
be an inherent or an acquired principle. If it
he inherent, that circumstance is, according to
the common modes of thinking, a sufficient
proof of its title to veneration. But if pro¬
vision be made in the constitution and circum¬
stances of all men, for uniformly producing it,
by processes similar to those which produce
other acquired sentiments, may not our rever¬
ence be augmented by admiration of that su¬
preme wisdom which, in such mental contri¬
vances, yet more brightly than in the lower
world of matter, accomplishes mighty purposes
by instruments so simple ? Should these specu¬
lations be thought to have any solidity by those
who are accustomed to such subjects, it would
be easy to unfold and apply them so fully, that
they may be thoroughly apprehended by every
intelligent person.
4. The most palpable defect of Butler’s scheme
is, that it affords no answer to the question,
“ What is the distinguishing quality common to
all right actions ?” If it were answered, “ Their
criterion is, that they are approved and com¬
manded by conscience,” the answerer would
find that he was involved in a vicious circle;
for conscience itself could be no otherwise de¬
fined than as the faculty which approves and
commands right actions.
There are few circumstances more remarkable
than the small number of Butler’s followers in
Ethics; and it is perhaps still more observable,
that his opinions were not so much rejected as
overlooked. It is an instance of the importance
of style. No thinker so great was ever so bad
a writer. Indeed, the ingenious apologies which
have been lately attempted for this defect, amount
to no more than that his power of thought was
too much for his skill in language. How gene¬
ral must the reception have been of truths so cer¬
tain and momentous as those contained in But¬
ler’s Discourses,—with how much more clear
ness must they have appeared to his own great
understanding, if he had possessed the strength
and distinctness with which Hobbes enforces
odious falsehood, or the unspeakable charm of
that transparent diction which clothed the un¬
fruitful paradoxes of Berkeley !
364
PRELIMINARY DISSERTATIONS.
HUTCHESON.*
This ingenious writer began to try bis own
strength by private Letters, written in his early
youth to Dr Clarke, the metaphysical patriarch
of his time; on whom young philosophers seem to
have considered themselves as possessing a claim,
which he had too much goodness to reject. His
correspondence with Hutcheson is lost; but we
may judge of its spirit by his answers to Butler,
and by one to Mr Henry Home,1 2 * afterwards
Lord Kames, then a young adventurer in the
prevalent speculations. Nearly at the same
period with Butler’s first publication,5 the writ¬
ings of Hutcheson began to show coincidences
with him, indicative of the tendency of moral
theory to a new form, to which an impulse had
been given by Shaftesbury, and which was roused
to activity by the adverse system of Clarke. Lord
Moles worth, the friend of Shaftesbury, patron¬
ised Hutcheson, and even criticised his manu¬
script. Though a Presbyterian, he was be¬
friended by King, archbishop of Dublin, him¬
self a metaphysician ; and he was aided by Mr
Synge, afterwards a bishop, to whom specula¬
tions somewhat similar to his own had occurred.
Butler and Hutcheson coincided in the two
important positions, that disinterested affections,
and a distinct moral faculty, are essential parts
of human nature. Hutcheson is a chaste and
simple writer, who imbibed the opinions, with¬
out the literary faults of his master, Shaftesbury.
He has a clearness of expression, and fulness of
illustration, which are wanting in Butler. But
he is inferior to both these writers in the
appearance at least of originality, and to Butler
especially in that philosophical courage which,
when it discovers the fountains of truth and
falsehood, leaves others to follow the streams.
He states as strongly as Butler, that “ the same
cause which determines us to pursue happiness
for ourselves, determines us both to esteem and
benevolence on their proper occasions—even
the very frame of our nature.”4 It is vain, as
he justly observes, for the patrons of a refined
selfishness to pretend that we pursue the happi¬
ness of others for the sake of the pleasure which
we derive from it; since it is apparent that there
could be no such pleasure if there had been no
previous affection. “ Had we no affection dis¬
tinct from self-love, nothing could raise a desire
of the happiness of others, but when viewed as
a mean of our own.”4 He seems to have been
the first who entertained just notions of the
formation of the secondary desires, which had
been overlooked by Butler. “ There must arise,
in consequence of our original desires, secondary
desires of every thing useful to gratify the pri¬
mary desire. Thus, as soon as we apprehend the
use of wealth or power to gratify our original de¬
sires, we also desire them. From their univer¬
sality as means arises the general prevalence of
these desires of wealth and power.”8 Proceed¬
ing farther in his zeal against the selfish system
than Lord Shaftesbury, who seems ultimately to
rest the reasonableness of benevolence on its
subserviency to the happiness of the individual,
he represents the moral faculty to be, as well as
self-love and benevolence, a calm general im¬
pulse, which may and does impel a good man to
sacrifice not only happiness, but even life itself,
to virtue.
As Mr Locke had spoken of an internal
sensation,—Lord Shaftesbury once or twice of
a reflex sense, and once of a moral sense,—
Hutcheson, who had a steadier, if not a clear¬
er view of the nature of conscience than But¬
ler, calls it a Moral Sense; a name which
quickly became popular, and continues to he
a part of philosophical language. By sense,
he understood a capacity of receiving ideas, to¬
gether with pleasures and pains, from a class of
1 Born in Ireland in 1694; died at Glasgow in 1747-
* Woodhouselee’s Life of Lord Karnes, vol. I. Append. No. 3. ,
* The first edition of Butler’s Sermons was published in 1726, in which year also appeared the second edition or Hutcne-
son’s Inquiry into Beauty and Virtue. The Sermons had been preached some years before, though there is no likelihood that
the contents could have reached a young teacher at Dublin. The place of Hutcheson’s birth is not mentioned ni any ac¬
count known to me. Ireland may be truly said to be “ incuriosa suornm."
4 Inquiry, p. 152. & Essay on the Passions, p. 17. * Ibid- P- 8.
DISSERTATION SECOND.
365
objects. The term moral was used to describe
the particular class in question. It implied
only that conscience was a separate element in
our nature, and that it was not a state or act of
the understanding. According to him, it also
implied that it was an original and implanted
principle; but every other part of his theory
might be embraced by those who hold it to be
derivative.
The object of moral approbation, according
to him, is general benevolence ; and he carries
this generous error so far as to deny that pru¬
dence, as long as it regards ourselves, can be
morally approved;—an assertion contradicted by
every man’s feelings, and to which we owe the
Dissertation on the Nature of Virtue which But¬
ler annexed to his Analogy. By proving that all
virtuous actions produce general good, he fancied
that he had proved the necessity of regarding
the general good in every act of virtue;—an in¬
stance of that confusion of the theory of moral
sentiments with the criterion of moral actions,
against which the reader was warned at the open¬
ing of this Dissertation, as fatal to Ethical Philo¬
sophy. He is chargeable, like Butler, with a
vicious circle, in describing virtuous acts as those
which are approved by the moral sense, while he
at the same time describes the moral sense as the
faculty which perceives and feels the morality
of actions.
He was the father of speculative philosophy in
Scotland, at least in modern times; for though
in the beginning of the sixteenth century the
Scotch are said to have been known through¬
out Europe by their unmeasured passion for
dialectical subtilties,1 and though this metaphy¬
sical taste was nourished by the controversies
which followed the Reformation, yet it languish¬
ed, with every other intellectual taste and talent,
from the Restoration, first silenced by civil dis
orders, and afterwards repressed by an exem¬
plary but unlettered clergy, till the philosophy
of Shaftesbury was brought by Hutcheson from
Ireland. We are told by the writer of his Life,
(a fine piece of philosophical biography) that “ he
had a remarkable degree of rational enthusiasm
for learning, liberty, religion, virtue, and human
happiness2 that he taught in public with per¬
suasive eloquence; that his instructive conversa¬
tion was at once lively and modest; that he unit¬
ed pure manners with a kind disposition. What
wonder that such a man should have spread the
love of knowledge and virtue around him, and
should have rekindled in his adopted country a
relish for the sciences which he cultivated ! To
him may also be ascribed that proneness to mul¬
tiply ultimate and original principles in human
nature, which characterized the Scottish School
till the second extinction of a passion for meta¬
physical speculation in Scotland. A careful
perusal of the writings of this now little studied
philosopher will satisfy the well-qualified reader,
that Dr Adam Smith’s ethical speculations are
not so unsuggested as they are beautiful.
BERKELEY.*
This great metaphysician was so little a mo- as a touchstone of metaphysical sagacity ; show-
ralist, that it requires the attraction of his name ing those to be altogether without it, who, like
to excuse its introduction here. His Theory of Johnson and Beattie, believed that his specula-
Vision contains a great discovery in mental phi- tions were sceptical, that they implied any dis-
losophy. His immaterialism is chiefly valuable trust in the senses, or that they had the smallest
1 The character given of the Scotch by the famous and unfortunate Servetus, in his edition of Ptolemy, (1533) is in
many respects curious. “ Gallis amicissimi, Anglorumque regi maxime infesti. Subita ingema et in ultionem prona, fero-
ciaque. In bello fortes, inedke, vigiliae, algoris patientissimi, decenti forma sed cultu neghgention; invidi natura et
caeterorum mortalium contemptores i ostentant plus nimio nobilitatem suam, et in summa etiam egcstate suum genus ad regiam
stirpem referunt, nec non dialecticis argutiis sim blandiuntur.”—Subita ingenia is an expression equivalen o le
“ Praefervidum Scotorum ingenium” of Buchanan. Churchill almost agrees in words with Seivetus.
Whose lineage springs
From great and glorious, though forgotten kings.
And the strong antipathy of the late King George III. to what he called “ Scotch Metaphysics, proves t ie permanency
of the last part of the national character.
2 Life by Dr Leechman, prefixed to Hutcheson’s System of Moral Philosophy, 1755.
* Born near Thomastown in Ireland, in 1684 ; died at Oxford in 1753.
366
PRELIMINARY DISSERTATIONS.
tendency to disturb reasoning or alter conduct.
Ancient learning, exact science, polished socie¬
ty, modern literature, and the fine arts, contrib¬
uted to adorn and enrich the mind of this ac¬
complished man. All his contemporaries agreed
with the satirist in ascribing
I
To Berkeley every virtue under heaven.
Adverse factions and hostile wits concurred
only in loving, admiring, and contributing to
advance him. The severe sense of Swift endur¬
ed his visions; the modest Addison endeavour¬
ed to reconcile Clarke to his ambitious specula¬
tions. His character converted the satire of
Pope into fervid praise. Even the discerning,
fastidious, and turbulent Atterbury said, after
an interview with him, “ So much understand¬
ing, so much knowledge, so much innocence,
and such humility, I did not think had been the
portion of any but angels, till I saw this gentle¬
man.”1 “ Lord Bathurst told me, that the
Members of the Scriblerus Club being met at
his house at dinner, they agreed to rally Berke¬
ley, who was also his guest, on his scheme at
Bermudas. Berkeley, having listened to the
many lively things they had to say, begged to
be heard in his turn, and displayed his plan
with such an astonishing and animating force of
eloquence and enthusiasm, that they were struck
dumb, and after some pause, rose all up together,
with earnestness exclaiming, c Let us set out
with him immediately.’”2 It was when thus
beloved and celebrated that he conceived, at the
age of forty-five, the design of devoting his life
to reclaim and convert the natives of North
America; and he employed as much influence
and solicitation as common men do for their
most prized objects, in obtaining leave to resign
his dignities arid revenues, to quit his accom¬
plished and affectionate friends, and to bury
himself in what must have seemed an intellec¬
tual desert. After four years’ residence at New¬
port in Rhode Island, he was compelled, by the
refusal of Government to furnish him with
funds for his College, to forego his work of he¬
roic, or rather godlike benevolence; though not
without some consoling forethought of the for¬
tune of the country where he had sojourned.
Westward the course of empire takes its way.
The first four acts already past,
A fifth shall close the drama with the day,
Time’s noblest offspring is its last.
Thus disappointed in his ambition of keeping a
School for Savage children, at a salary of a hun¬
dred pounds by the year, he was received, on
his return, with open arms by the philosophical
queen, at whose metaphysical parties he made
one with Sherlock, who, as well as Smalridge,
was his supporter, and with Hoadley, who, fol¬
lowing Clarke, was his antagonist. By her in¬
fluence, he was made bishop of Cloyne. It is
one of his highest boasts, that though of Eng¬
lish extraction, he was a true Irishman, and
the first eminent Protestant, after the unhappy
contest at the Revolution, who avowed his love
for all his countrymen. He asked, <{ Whether
their habitations and furniture were not more
sordid than those of the savage Americans?”3
“ Whether a scheme for the welfare of this nation
should not take in the whole inhabitants ?” and,
“ Whether it was a vain attempt^ to project the
flourishing of our Protestant gentry^ exclusive of
the bulk of the natives ?”4 He proceeds to pro¬
mote the reformation suggested in this pregnant
question by a series of Queries, intimating, with
the utmost skill and address, every reason that
proves the necessity, and the safety, and the
wisest mode of adopting his suggestion. He
contributed, by a truly Christian address to the
Roman Catholics of his diocese, to their perfect
quiet during the rebellion of 1745; and soon
after published a letter to the clergy of that per¬
suasion, beseeching them to inculcate indus¬
try among their flocks, for which he received
their thanks. He tells them, that it was a say¬
ing among the negro slaves, “ if negro were not
negro, Irishman would be negro.” It is difficult
to read these proofs of benevolence and fore¬
sight without emotion, at the moment when,5
after a lapse of near a century, his suggestions
have been at length, at the close of a struggle
of twenty-five years, adopted, by the admis-
* See his Querist, 358; published in 1735.
4 Ibid. 255. 4 April 1829.
1 Duncombe’s Letters, 106, 107.
* Warton on Pope.
DISSERTATION SECOND.
367
si on of the whole Irish nation to the privileges
of the British Constitution. The patriotism of
Berkeley was not, like that of Swift, tainted
by disappointed ambition; nor was it, like
Swift’s, confined to a colony of English Pro¬
testants. Perhaps the Querist contains more
hints, then original, still unapplied in legislation
and political economy, than are to be found
in any equal space. From the writings of his
advanced years, when he chose a medical Tract1 * 3
to be the vehicle of his philosophical reflections,
though it cannot be said that he relinquished
his early opinions, it is at least apparent that
his mind had received a new bent, and was
habitually turned from reasoning towards con¬
templation. His immaterialism indeed modest¬
ly appears, but only to purify and elevate our
thoughts, and to fix them on Mind, the para¬
mount and primeval principle of all things.
“ Perhaps,” says he, “ the truth about innate
ideas may be, that there are properly no ideas
or passive objects in the mind but what are de¬
rived from sense, but that there are also, be¬
sides these, her own acts and operations—such
are notionsa statement which seems once
more to admit general conceptions, and which
might have served, as well as the parallel pass¬
age of Leibnitz, as the basis of the modern phi¬
losophy of Germany. From these compositions
of his old age, he appears then to have recurred
with fondness to Plato and the later Platonists;
writers from whose mere reasonings an intellect
so acute could hardly hope for an argumentative
satisfaction of all its difficulties, and whom he
probably rather studied as a means of inuring
his mind to objects beyond the visible diurnal
sphere, and of attaching it, through frequent
meditation, to that perfect and transcendent
goodness to which his moral feelings always
pointed, and which they incessantly strove to
grasp. His mind, enlarging as it rose, at length
receives every theist, however imperfect his be¬
lief, to a communion in its philosophic piety.
“ Truth,” he beautifully concludes, “ is the cry
of all, but the game of a few. Certainly, where
it is the chief passion, it does not give way to
vulgar cares, nor is it contented with a little
ardour in the early time of life ; active perhaps
to pursue, but not so fit to weigh and revise.
He that would make a real progress in know¬
ledge, must dedicate his age as well as youth,
the later growth as well as first fruits, at the
altar of Truth.” So did Berkeley, and such were
almost his latest words.
His general principles of Ethics may be shortly
stated in his own words :—“ As God is a being
of infinite goodness, his end is the good of his
creatures. The general wellbeing of all men of
all nations, of all ages of the world, is that which
he designs should be procured by the concur¬
ring actions of each individual.” Having stated
that this end can be pursued only in one of two
ways—either by computing the consequences of
each action, or by obeying rules which generally
tend to happiness—and having shown the first
to be impossible, he rightly infers, “ that the
end to which God requires the concurrence of
human actions, must be carried on by the ob¬
servation of certain determinate and universal
rules or moral precepts, which in their own na¬
ture have a necessary tendency to promote the
wellbeing of mankind, taking in all nations and
ages, from the beginning to the end of the
world.”8 A romance, of which a journey to
an Utopia, in the centre of Africa, forms the
chief part, called The Adventures of Signor Gau-
dentio di Lucca, has been commonly ascribed to
him; probably on no other ground than its union
of pleasing invention with benevolence and ele¬
gance.5 Of the exquisite grace and beauty of
his diction, no man accustomed to English com¬
position can need to be informed. His works
are, beyond dispute, the finest models of phi¬
losophical style since Cicero. Perhaps they
surpass those of the orator, in the wonderful
art by which the fullest light is thrown on
the most minute and evanescent parts of the
most subtile of human conceptions. Perhaps
he also surpassed Cicero in the charm of sim¬
plicity, a quality eminently found in Irish wri¬
ters before the end of the eighteenth century;
conspicuous in the masculine severity of Swift,
1 Siris, or Reflections on Tar Water.
* Sermon in Trinity College Chapel, on Passive Obedience, 1712.
3 Gentleman's Magazine, January 1777*
368
PRELIMINARY DISSERTATIONS.
in the Platonic fancy of Berkeley, in the native
tenderness and elegance of Goldsmith, and not
withholding its attractions from Hutcheson and
Leland, writers of classical taste, though of
inferior power. The two Irish philosophers
of the eighteenth century may be said to have
co-operated in calling forth the metaphysical
genius of Scotland; for, though Hutcheson
spread the taste, and furnished the principles,
yet Berkeley undoubtedly produced the scep¬
ticism of Hume, which stimulated the instinc¬
tive school to activity, and was thought incap¬
able of confutation, otherwise than by their
doctrines.
DAVID HUME.1
The Life of Mr Hume, written by himself, is
remarkable above most, if not all writings of that
sort, for hitting the degree of interest between
coldness and egotism which becomes a modest
man in speaking of his private history. Few
writers, whose opinions were so obnoxious, have
more perfectly escaped every personal imputa¬
tion. Very few men of so calm a character have
been so warmly beloved. That he approached
to the character of a perfectly good and wise
man, is an affectionate exaggeration, for which
his friend Dr Smith, in the first moments of
his sorrow, may well he excused.2 * But such a
praise can never be earned without passing
through either of the extremes of fortune; with¬
out standing the test of temptations, dangers,
and sacrifices. It may he said with truth, that
the private character of Mr Hume exhibited all
the virtues which a man of reputable station,
under a mild government, in the quiet times of
a civilized country, has often the opportunity to
practise. He showed no want of the qualities
which fit men for more severe trials. Though
others had warmer affections, no man was a
kinder relation, a more unwearied friend, or
more free from meanness and malice. His cha¬
racter was so simple, that he did not even affect
modesty; hut neither his friendships nor his de¬
portment were changed by a fame which filled
all Europe. His good nature, his plain manners,
and his active kindness, procured him at Paris
the enviable name of the good David, from a
society not so alive to goodness, as without
reason to place it at the head of the qualities of
a celebrated man.s His whole character is faith¬
fully and touchingly represented in the story of
La Roche,4 where Mr Mackenzie, without con¬
cealing Mr HumeV opinions, brings him into
contact with scenes of tender piety, and yet pre¬
serves the interest inspired by genuine and un¬
alloyed, though moderated feelings and affec¬
tions. The amiable and venerable patriarch of
Scottish Literature was averse from the opinions
of the philosopher on whom he has composed
this best panegyric. He tells us that he read the
manuscript to Dr Smith, “ who declared he did
not find a syllable to object to, hut added, with
his characteristic absence of mind, that he was
surprised he had never heard of the anecdote be¬
fore.”5 So lively was the delineation thus sanc¬
tioned by the most natural of all testimonies.
Mr Mackenzie indulges his own religious feel¬
ings by modestly intimating, that Dr Smith’s
answer seemed to justify the last words of the
tale, “ that there were moments when the phi¬
losopher recalled to his mind the venerable fi¬
gure of the good La Roche, and wished that he
had never doubted.” To those who are strangers
to the seductions of paradox, to the intoxication
of fame, and to the bewitchment of prohibited
opinions, it must be unaccountable, that he who
revered benevolence should, without apparent
regret, cease to see it on the Throne of the Uni¬
verse. It is a matter of wonder that his habitual
esteem for every fragment and shadow of moral
excellence should not lead him to envy those
who contemplated its perfection in that living
and paternal character which gives it a power
over the human heart.
On the other hand, if we had no experience
1 Born at Edinburgh in 1711; died there in 1776-
2 Dr Smith’s Letter to Mr Strahan. annexed to the Life of Hume.
* See Notes and Illustrations, note P.
4 Mirror, Nos. 42, 43, 44.
6 Mackenzie’s Life of John Home, p. 21.
DISSERTATION SECOND.
369
of the power of. opposite opinions in producing
irreconcilable animosities, we might have hoped
that those who retained such high privileges
would have looked with more compassion than
dislike on a virtuous man who had lost them.
In such cases it is too little remembered, that
repugnance to hypocrisy, and impatience of
long concealment, are the qualities of the best
formed minds; and that, if the publication of
some doctrines proves often painful and mis¬
chievous, the habitual suppression of opinion is
injurious to reason, and very dangerous to sin¬
cerity. Practical questions thus arise, so diffi¬
cult and perplexing, that their determination
generally depends on the boldness or timidity of
the individual,—on his tenderness for the feel¬
ings of the good, or his greater reverence for the
free exercise of reason. The time is not yet
come when the noble maxim of Plato, “ that
every soul is unwillingly deprived of truth,” will
be practically and heartily applied by men to
the honest opponents who differ from them most
widely.
In his twenty-seventh year he published at
London the Treatise of Human Nature, the first
systematic attack on all the principles of know¬
ledge and belief, and the most formidable, if
universal scepticism could ever be more than a
mere exercise of ingenuity.1 This memorable
work was reviewed in a Journal of that time,2
in a criticism not distinguished by ability, which
affects to represent the style of a very clear
writer as unintelligible—sometimes from a pur¬
pose to insult, but oftener from sheer dulness—
which is unaccountably silent respecting the
consequences of a sceptical system; and which
concludes with a prophecy so much at variance
with the general tone of the article, that it
would seem to be added by a different hand.
“ It bears incontestable marks of a great capa¬
city, of a soaring genius, but young, and Rot
yet thoroughly practised. Time and use may
ripen these qualities in the author, and we shall
probably have reason to consider this, com¬
pared with his later productions, in the same
light as we view the juvenile works of Milton,
or the first manner of Raphael.”
The great speculator did not, in this work,
amuse himself, like Bayle, with dialectical ex¬
ercises, which only inspire a disposition towards
doubt, by showing in detail the uncertainty of
most opinions. He aimed at proving, not that
nothing was known, but that nothing could
be known;—from the structure of the under¬
standing to demonstrate, that we are doomed
for ever to dwell in absolute and universal ig¬
norance. It is true that such a system of uni¬
versal scepticism never can be more than an in¬
tellectual amusement, an exercise of subtilty;
of which the only use is to check dogmatism,
but which perhaps oftener provokes and pro¬
duces that much more common evil. As those
dictates of experience which regulate conduct
must be the objects of belief, all objections
which attack them in common with the prin¬
ciples of reasoning must be utterly ineffectual.
Whatever attacks every principle of belief can
destroy none. As long as the foundations of
knowledge are allowed to remain on the same
level (be it called of certainty or uncertainty) with
the maxims of life, the whole system of human
conviction must continue undisturbed. When
the sceptic boasts of having involved the results
of experience and the elements of geometry in
the same ruin with the doctrines of religion and
the principles of philosophy, he may be answered.
That no dogmatist ever claimed more than the
same degree of certainty for these various con¬
victions and opinions; and that his scepticism,
therefore, leaves them in the relative condition
in which it found them. No man knew better,
or owned more frankly than Mr Hume, that to
1 Sextus, a physician of the empirical, i. e. anti-theoretical school, who lived at Alexandria in the reign of Antoninus f
Pius, has preserved the reasonings of the ancient Sceptics as they were to be found in their most improved state, in the
writings of /Enesidemus, a Cretan, who was a Professor in the same city, soon after the reduction of Egypt into a Homan
province. The greater part of the grounds of doubt are very shallow and popular. There are, among them, intimations
of the argument against a necessary connection of causes with effects, afterwards better presented by Glanville in his Scepsis
Sdentifica. See Notes and Illustrations, note Q,.
• History of the Works of the Learned, November and December 1739? p. 353—404. This Heview is attributed by some
(Chalmers, Biographical Dictionary) to Warburton, but certainly without foundation.
DISS. II 3 A
370
PRELIMINARY DISSERTATIONS.
this answer there is no serious reply. Univer¬
sal scepticism involves a contradiction in terms.
It is a belief that there can be no belief. It is an
attempt of the mind to act without its structure,
and by other laws than those to which its nature
has subjected its operations. To reason without
assenting to the principles on which reasoning is
founded, is not unlike an effort to feel without
nerves, or to move without muscles. No man
can be allowed to be an opponent in reasoning, who
does not set out with admitting all the principles,
without the admission of which it is impossible to
reason.1 It is indeed a puerile, nay, in the eye
of wisdom, a childish play, to attempt either to
establish or to confute principles by argument,
which every step of that argument must pre¬
suppose. The only difference between the two
cases is, that he who tries to prove them can
do so only by first taking them for granted; and
that he who attempts to impugn them falls at
the very first step into a contradiction, from
which he never can rise.
It must, however, be allowed, that universal
scepticism has practical consequences of a very
mischievous nature. This is because its univer¬
sality is not steadily kept in view, and con¬
stantly borne in mind. If it were, the above
short and plain remark would be an effectual
antidote to the poison. But in practice, it is
an armoury from which weapons are taken
to be employed against some opinions, while
it is hidden from notice that the same weapon
would equally cut down every other conviction.
It is thus that Mr Hume’s theory of causation is
used as an answer to arguments for the exist¬
ence of the Deity, without warning the reader
that it would equally lead him not to expect
that the sun will rise to-morrow. It must also
he added, that those who are early accustomed
to dispute first principles are never likely to
acquire, in a sufficient degree, that earnestness
and that sincerity, that strong love of truth, and
that conscientious solicitude for the formation of
just opinions, which are not the least virtues
of men, hut of which the cultivation is the more
especial duty of all who call themselves philo¬
sophers. 8
It is not an uninteresting fact, that Mr Hume
having been introduced by Lord Kames (then
Mr Henry Home) to Dr Butler, sent a copy of
his Treatise to that philosopher at the moment
of his preferment to the bishopric of Durham;
and that the perusal of it did not deter the
philosophic prelate from “ everywhere recom¬
mending Mr Hume’s Moral and Political Es¬
says,”1 * 3 published two years afterwards;—Essays
which it would indeed have been unworthy of
such a man not to have liberally commended,
for they, and those which followed them, what¬
ever may he thought of the contents of some of
them, must be ever regarded as the best models
in any language, of the short hut full, of the
clear and agreeable, though deep discussion of
difficult questions.
Mr Hume considered his Enquiry concerning
the Principles of Morals as the best of his wri¬
tings. It is very creditable to his character,
that he should have looked hack with most
complacency on a Tract the least distinguished
by originality, and the least tainted with para¬
dox, among his philosophical works; hut deserv¬
ing of all commendation for the elegant perspi¬
cuity of the style, and the novelty of illustration
and inference with which he unfolded to general
readers a doctrine too simple, too certain, and
too important, to remain till his time undis¬
covered among philosophers. His diction has,
indeed, neither the grace of Berkeley nor the
strength of Hobbes; hut it is without the verbo¬
sity of the former, or the rugged sternness of
the latter. His manner is more lively, more
easy, more ingratiating, and, if the word may
1 This maxim, which contains a sufficient answer to all universal scepticism, or, in other words, to all scepticism properly
so called, is significantly conveyed in the quaint title of an old and rare book, entitled, Sciti, sivc Sceptices et Scepticorum a
Jure Disputationis Exclusio, by Thomas White, the metaphysician of the English Catholics in modern times—“Fortu¬
nately,” says the illustrious sceptic himself, “ since Reason is incapable of dispelling these clouds. Nature herself suffices for that
purpose, and cures me of this philosophical delirium" (Treatise of Human Nature, I. 467); almost in the sublime and immor¬
tal words of Pascal: La Raison confond les Dogmatistes, et la Nature les Sceptiques.
* It would be an act of injustice to those readers who are not acquainted with that valuable volume entitled, Essays
on the Formation of Opinions, not to refer them to it as enforcing that neglected part of morality. To it may be added, a
masterly article in the Westminster Review, occasioned by the Essays.
* Woodhouselee’s Life of Kames, I. 86, 104.
DISSERTATION SECOND.
371
be so applied, more amusing, than that of any
other metaphysical writer.1 2 He knew himself
too well to be, as Dr Johnson asserted, an imi¬
tator of Voltaire; who, as it were, embodied in
his own person all the wit and quickness and
versatile ingenuity of a people which surpasses
other nations in these brilliant qualities. If he
must be supposed to have had an eye on any
French writer, it would be a more plausible
guess, that he sometimes copied, with a tem¬
perate hand, the unexpected thoughts and famil¬
iar expressions of Fontenelle. Though he care¬
fully weeded his writings in their successive
editions, yet they still contain Scotticisms and
Gallicisms enough to employ the successors of
such critics as those who exulted over the Pata-
vinity of the Roman Historian. His own great
and modest mind would have been satisfied with
the praise which cannot be withheld from him,
that there is no writer in our language who,
through long works, is more agreeable; and it
is no derogation from him, that, as a Scots¬
man, he did not reach those native and secret
beauties, characteristical of a language, which
are never attained, in elaborate composition,
but by a very small number of those who famil¬
iarly converse in it from infancy.
The Enquiry affords perhaps the best speci¬
men of his style. In substance, its chief merit
is the proof, from an abundant enumeration of
particulars, that all the qualities and actions of
the mind which are generally approved by man¬
kind agree in the circumstance of being useful
to society. In the proof, (scarcely necessary)
that benevolent affections and actions have that
tendency, he asserts the real existence of these
affections with unusual warmth; and he well
abridges some of the most forcible arguments of
Butler, * whom it is remarkable that he does not
mention. To show the importance of his prin¬
ciple, he very unnecessarily distinguishes the
comprehensive duty of justice, from other parts
of morality, as an artificial virtue, for which our
respect is solely derived from notions of utility.
If all things were in such plenty that there could
never be a want, or if men were so benevolent
as to provide for the wants of others as much as
for their own, there would, says he, in neither
case be any justice, because there would be no
need for it. But it is evident that the same
reasoning is applicable to every good affection
and right action. None of them could exist if
there were no scope for their exercise. If there
were no suffering, there could be no pity and no
relief. If there were no offences, there could be
no placability. If there were no crimes, there
could be no mercy. Temperance, prudence, pa¬
tience, magnanimity, are qualities of which the
value depends on the evils by which they are
respectively exercised.3 4
On purity of manners, it must be owned that
Mr Hume, though he controverts no rule, yet
treats vice with too much indulgence. It was
his general disposition to distrust virtues which
are liable to exaggeration, and may be easily
counterfeited. The ascetic pursuit of purity,
and hypocritical pretences to patriotism, had too
much withdrawn the respect of his equally calm
and sincere nature from these excellent virtues;
more especially as severity in both these respects
was often at apparent variance with affection,
which can neither be long assumed, nor ever
overvalued. Yet it was singular that he who,
in his Essay on Polygamy and Divorce,* had so
1 These commendations are so far from being at variance with the remarks of the late most ingenious Dr Thomas Brown,
on Mr Hume’s “ mode of writing,” (Enquiry into the Relation of Cause and Effect, 3d ed. 327) that they may rather be re¬
garded as descriptive of those excellencies of which the excess produced the faults of Mr Hume as a mere searcher and
teacher; justly, though perhaps severely, animadverted on by Dr Brown.
2 Enquiry, sect. ii. part i., especially the concluding paragraphs; those which precede being more his own.
3 “ Si nobis, cum ex hac vita migraverimus, in beatorum insulis, ut fabulae ferunt, immortale sevum degere liceret, quid
opus esset eloquentia, cum judicia nulla fierent ? aut ipsis etiam virtutibus ? Nec enim fortitudine indigeremus, nullo pro-
posito aut laboreaut periculo; nec justitia, cum esset nihil quod appeteretur alieni; nec temperantia, quae regeret eas quae nullae
essent libidines: ne prudentia quidem egeremus, nullo proposito delectu bonorum et malorum. Una igitur essemus beati
cogmtioneyerum et scientia.” (Cicero. Fragm. ap. Augustin, de Trinit. iv. 2.) Cicero is more extensive, and therefore
more consistent, than Hume ; but his enumeration errs both by excess and defect. He supposes knowledge to render
beings happy in this imaginary state, without stooping to inquire how. He omits a virtue which might well exist in it,
though we cannot conceive its formation in such a state—the delight in each other’s wellbeing ; and he omits a conceivable
though unknown vice, that of unmixed ill-will, which would render such a state a hell to the wretch who harboured the
malevolence.
4 Essays and Treatises, vol I.
372
PRELIMINARY DISSERTATIONS.
well shown the connection of domestic ties with
the outward order of society, should not have
perceived their deeper and closer relation to all
the social feelings of human nature. It cannot
he enough regretted, that, in an Enquiry wiit-
ten with a very moral purpose, his habit of ma¬
king truth attractive, by throwing over her the
dress of paradox, should have given him for a
moment the appearance of weighing the mere
amusements of society and conversation against
domestic fidelity, which is the preserver of do¬
mestic affection, the source of parental fondness
and filial regard, and, indirectly, of all the kind¬
ness which exists between human beings. That
families are schools where the infant heart learns
to love, and that pure manners are the ce¬
ment which alone holds these schools together,
are truths so certain, that it is wonderful he
should not have betrayed a stronger sense of
their importance. No one could so well have
proved that all the virtues of that class, in their
various orders and degrees, minister to the be¬
nevolent affections; and that every act which
separates the senses from the affections tends, in
some degree, to deprive kindness of its natural
auxiliary, and to lessen its prevalence in the
world. It did not require his sagacity to discover
that the gentlest and tenderest feelings flourish
only under the stern guardianship of these severe
virtues. Perhaps his philosophy was loosened,
though his life was untainted, by that universal
and undistinguishing profligacy which prevailed
on the Continent, from the regency of the Duke
of Orleans to the French revolution; the most
dissolute period of European history, at least
since the Roman emperors.1 At Rome, indeed,
the connection of licentiousness with cruelty,
which, though scarcely traceable in individuals,
is generally very observable in large masses,
bore a fearful testimony to the value of austere
purity. The alliance of these remote vices
seemed to be broken in the time of Mr Hume.
Pleasure, in a more improved state of society,
seemed to return to her more natural union with
kindness and tenderness, as well as with refine¬
ment and politeness. Had he lived fourteen
years longer, however, he would have seen, that
the virtues which guard the natural seminaries
of the affections are their only true and lasting
friends. The demand of all well-informed men
for the improvement of civil institutions—the
demand of classes of men growing in intelligence,
to be delivered from a degrading inferiority, and
admitted to a share of political power propor¬
tioned to their new importance, being feebly yet
violently resisted by those ruling Castes who
neither knew howto yield nor how to withstand—
being also attended by very erroneous principles
of legislation, having suddenly broken down the
barriers (imperfect as these were) of law and
government, led to popular excesses, desolat¬
ing wars, and a military dictatorship, which for
a long time threatened to defeat the reforma¬
tion, and to disappoint the hopes of mankind.
This tremendous convulsion threw a fearful light
on the ferocity which lies hid under the arts and
pleasures of corrupted nations; as earthquakes
and volcanoes disclose the layers which compose
the deeper parts of our planet, beneath a fertile
and flowery surface. A part of this dreadful re¬
sult may be ascribed, not improbably, to that
relaxation of domestic ties, unhappily natural to
the populace of vast capitals, and at that time
countenanced and aggravated by the example of
their superiors. Another part doubtless arose
from the barbarizing power of absolute govern¬
ment, or, in other words, of injustice in high
places. A very large portion attests, as strongly
as Roman history, though in a somewhat differ¬
ent manner, the humanizing efficacy of the family
virtues, by the consequences of the want of them
in the higher classes, whose profuse and ostenta¬
tious sensuality inspired the laborious and suffer¬
ing portion of mankind with contempt, disgust,
envy, and hatred.
The Enquiry is disfigured by another speck of
more frivolous paradox. It consists in the at¬
tempt to give the name of virtue to qualities of
the understanding; and it would not have de¬
served the single remark about to be made on
it, had it been the paradox of an inferior man.
He has altogether omitted the circumstance on
which depends the difference of our sentiments
regarding moral and intellectual qualities. We
1 See Notes and Illustrations, note It.
DISSERTATION SECOND.
373
admire intellectual excellence, but we bestow no
moral approbation on it. Such approbation has
no tendency directly to increase it, because it is
not voluntary. We cultivate our natural dis¬
position to esteem and love benevolence and
justice, because these moral sentiments, and the
expression of them, directly and materially dis¬
pose others, as well as ourselves, to cultivate
these two virtues. We cultivate a natural
anger against oppression, which guards our¬
selves against the practice of that vice, and be¬
cause the manifestation of it deters others from
its exercise. The first rude resentment of a
child is against every instrument of hurt. We
confine it to intentional hurt, when we are
taught by experience that it prevents only that
species of hurt; and at last it is still further li¬
mited to wrong done to ourselves or others, and
in that case becomes a purely moral sentiment.
We morally approve industry, desire of know¬
ledge, love of truth, and all the habits by which
the understanding is strengthened and rectified,
because their formation is subject to the will.1
But we do not feel a moral anger against folly
or ignorance, because they are involuntary. No
one but the religious persecutor, a mischievous
and overgrown child, wreaks his vengeance on
involuntary, inevitable, compulsory acts or states
of the understanding, which are no more affected
by blame than the stone which the foolish child
beats for hurting him. Reasonable men apply
to every thing which they wish to move, the
agent which is capable of moving it;—force to
outward substances, arguments to the under¬
standing, and blame, together with all other
motives, whether moral or personal, to the will
alone. It is as absurd to entertain an abhor¬
rence of intellectual inferiority or error, however
extensive or mischievous, as it would be to
cherish a warm indignation against earthquakes
or hurricanes. It is singular that a philosopher
who needed the most liberal toleration should,
by representing states of the understanding as
moral or immoral, have offered the most philo¬
sophical apology for persecution.
That general utility constitutes a uniform
ground of moral distinctions, is a part of Mr
Hume’s ethical theory which never can be im¬
pugned, until some example can be produced of
a virtue generally pernicious, or of a vice gene¬
rally beneficial. The religious philosopher who,
with Butler, holds that benevolence must be the
actuating principle of the Divine mind, will,
with Berkeley, maintain that pure benevolence
can prescribe no rules of human conduct but
such as are beneficial to men; thus bestowing
on the theory of Moral Distinctions the certainty
of demonstration in the eyes of all who believe
in God.
The other question of moral philosophy which
relates to the theory of Moral Approbation, has
been by no means so distinctly and satisfactorily
handled by Mr Hume. His general doctrine is,
that an interest in the wellbeing of others, im¬
planted by nature, which he calls Sympathy in
his Treatise of Human Nature, and much less
happily Benevolence in his subsequent Enquiry,*
prompts us to be pleased with all generally be¬
neficial actions. In this respect his doctrine
nearly resembles that of Hutcheson. He does
not trace his principle through the variety of
forms which our moral sentiments assume.
There are very important parts of them, of
which it affords no solution. For example,
though he truly represents our approbation, in
others, of qualities useful to the individual, as a
proof of benevolence, he makes no attempt to
explain our moral approbation of such virtues
as temperance and fortitude in ourselves. He
entirely overlooks that consciousness of the
rightful supremacy of the moral faculty over every
other principle of human action, without an ex¬
planation of which, ethical theory is wanting in
one of its vital organs.
Notwithstanding these considerable defects,
his proof from induction of the beneficial tend¬
ency of virtue, his conclusive arguments for
human disinterestedness, and his decisive ob¬
servations on the respective provinces of reason
and sentiment in morals, concur in ranking the
i “ In liac qusestione primas tenet Voluntas, qua, ut ait Augustinus, peccatur, et recte vivitur." (Hyperaspistes, DiatnU
advcrsus Servum Arbitrium Martini Lutheri, per Desiderium Erasmum Itotterdamensem.)
'* Essays and Treatises, vol. II.
374
PRELIMINARY DISSERTATIONS.
Enquiry with the ethical treatises of the highest quiry concerning Virtue, Butler’s Sermons, and
merit in our language,—with Shaftesbury’s En- Smith’s Theory of Moral Sentiments.
ADAM SMITH.1
The great name of Adam Smith rests upon
the Enquiry into the Nature and Causes of the
Wealth of Nations ; perhaps the only hook which
produced an immediate, general, and irrevoc¬
able change in some of the most important parts
of the legislation of all civilized states. The
works of Grotius, of Locke, and of Montesquieu,
which bear a resemblance to it in character, and
had no inconsiderable analogy to it in the ex¬
tent of their popular influence, were productive
only of a general amendment, not so conspicuous
in particular instances, as discoverable, after a
time, in the improved condition of human af¬
fairs. 2 3 * The work of Smith, as it touched those
matters which may he numbered, and measured,
and weighed, bore more visible and palpable
fruit. In a few years it began to alter laws and
treaties, and has made its way, throughout the
convulsions of revolution and conquest, to a due
ascendant over the minds of men, with far less
than the average obstructions of prejudice and
clamour, which choakthe channels through which
truth flows into practice. The most eminent of
those who have since cultivated and improved
the science will be the foremost to address their
immortal master, .
  Tenebris tantis tam clarum extollere lumen
Qui primus potuisti, inlustrans commoda vit^e,
Te sequor! (Lucret. lib. iii.)
In a science more difficult, because both ascend¬
ing to more simple general principles, and run¬
ning down through more minute applications,
though the success of Smith has been less com¬
plete, his genius is not less conspicuous. Per¬
haps there is no ethical work since Cicero’s Of¬
fices, of which an abridgement enables the reader
so inadequately to estimate the merit, as the
Theory of Moral Sentiments. This is not chiefly
owing to the beauty of diction, as in the case of
Cicero; but to the variety of explanations of life
and manners which embellish the book often
more than they illuminate the theory. Yet, on
the other hand, it must be owned that, for pure¬
ly philosophical purposes, few hooks more need
abridgement: for the most careful reader fre¬
quently loses sight of principles buried under
illustrations. The naturally copious and flow¬
ing style of the author is generally redundant,
and the repetition of certain formularies of the
system is, in the later editions, so frequent as to
be wearisome, and sometimes ludicrous. Per¬
haps Smith and Hobbes may be considered as
forming the two extremes of good style in our
philosophy; the first of graceful fulness falling
•into flaccidity; while the masterly concision of
the second is oftener tainted by dictatorial dry¬
ness. Hume and Berkeley, though they are
nearer the extreme of abundance,5 are probably
the least distant from perfection.
That mankind are so constituted as to sympa¬
thize with each other’s feelings, and to feel
pleasure in the accordance of these feelings, are
the only facts required by Hr Smith, and they
certainly must be granted to him. To adopt the
feelings of another, is to approve them. When
the sentiments of another are such as would be
excited in us by the same objects, we approve
them as morally proper. To obtain this accord,
it becomes necessary for him who enjoys or suf¬
fers, to lower his expression of feeling to the
point to which the by-stander can raise his fel¬
low-feelings ; on which are founded all the higli
virtues of self-denial and self-command; and it
is equally necessary for the by-stander to raise
his sympathy as near as he can to the level of
the original feeling. In all unsocial passions,
such as anger, we have a divided sympathy be¬
tween him who feels them and those who are the
1 Born in 1723 ; died in 1790.
* Notes and Illustrations, note S.
3 This remark is chiefly applicable to Hume’s Essays. His Treatise of Human Nature is more Hobbian in its general
tenor, though it has Ciceronian passages.
DISSERTATION SECOND.
375
objects of them. Hence the propriety of ex¬
tremely moderating them. Pure malice is al¬
ways to he concealed or disguised, because all
sympathy is arrayed against it. In the private
passions, where there is only a simple sympathy—
that with the original passion—the expression has
more liberty. The benevolent affections, where
there is a double sympathy—with those who feel
them, and those who are their objects—are the
most agreeable, and may he indulged with the
least apprehension of finding no echo in other
breasts. Sympathy with the gratitude of those
who are benefited by good actions, prompts us
to consider them as deserving of reward, and
forms the sense of merit; as fellow-feeling with the
resentment of those who are injured by crimes
leads us to look on them as worthy of punishment,
and constitutes the seme of demerit. These senti¬
ments require not only beneficial actions, hut be¬
nevolent motives for them; being compounded,
in the case of merit, of a direct sympathy with the
good disposition of the benefactor, and an indirect
sympathy with the persons benefited; in the op¬
posite case, with precisely opposite sympathies.
He who does an act of wrong to another to gratify
his own passions, must not expect that the spec¬
tators, who have none of his undue partiality to
his own interest, will enter into his feelings. In
such a case, he knows that they will pity the
person wronged, and he full of indignation
against him. When he is cooled, he adopts the
sentiments of others on his own crime, feels
shame at the impropriety of his former passion,
pity for those who have suffered by him, and a
dread of punishment from general and just re¬
sentment. Such are the constituent parts of
remorse.
Our moral sentiments respecting ourselves
arise from those which others feel concerning
us. We feel a self-approbation whenever we
believe that the general feeling of mankind co¬
incides with that state of mind in which we our¬
selves were at a given time. “ We suppose
ourselves the spectators of our own behaviour,
and endeavour to imagine what effect it would
in this light produce in us.” We must view our
own conduct with the eyes of others before we
can judge it. The sense of duty arises from
putting ourselves in the place of others, and
adopting their sentiments respecting our own
conduct. In utter solitude there could have
been no self-approbation. The rules of morality
are a summary of those sentiments; and often
beneficially stand in their stead when the self-
delusions of passion would otherwise hide from
us the non-conformity of our state of mind
with that which, in the circumstances, can be
entered into and approved by impartial by¬
standers. It is hence that we learn to raise our
mind above local or temporary clamour, and to
fix our eyes on the surest indications of the ge¬
neral and lasting sentiments of human nature.
“ When we approve of any character or action,
our sentiments are derived from four sources:
first, we sympathize with the motives of the
agent; secondly, we enter into the gratitude of
those who have been benefited by his actions;
thirdly, we observe that his conduct has been
agreeable to the general rules by which those
two sympathies generally act; and, last of all,
when we consider such actions as forming part
of a system of behaviour which tends to promote
the happiness either of the individual or of so¬
ciety, they appear to derive a beauty from this
utility, not unlike that which we ascribe to any
well-contrived machine.”1
REMARKS.
That Smith is the first who has drawn the at¬
tention of philosophers to one of the most cu¬
rious and important parts of human nature—
who has looked closely and steadily into the
workings of Sympathy, its sudden action and re¬
action, its instantaneous conflicts and its emo¬
tions, its minute play and varied illusions—is
sufficient to place him high among the culti¬
vators of mental philosophy.
He is very original in applications and expla¬
nations; though, for his principle, he is some¬
what indebted to Butler, more to Hutcheson,
and most of all to Hume. These writers, except
Hume in his original work, had derived sym-
1 Theory of Moral Sentiments, II. 304. Edinb. 1801.
376
PRELIMINARY DISSERTATIONS.
pathy, or great part of it, from benevolence.1 2
Smith, with deeper insight, inverted the order.
The great part performed by various sympathies
in moral approbation was first unfolded by him;
and besides its intrinsic importance, it strength¬
ened the proofs against those theories which
ascribe that great function to Reason. Anothei
great merit of the theory of sympathy is, that it
brings into the strongest light that most import¬
ant characteristic of the moral sentiments which
consists in their being the only principles lead¬
ing to action, and dependent on emotion or sen¬
sibility, with respect to the objects of which,
it is not only possible but natural for all man¬
kind to agree.3
The main defects of this theory seem to be the
following.
L Though it is not to be condemned for de¬
clining inquiry into the origin of our fellow-
feeling, which, being one of the most certain of
all facts, might well be assumed as ultimate in
speculations of this nature, it is evident that the
circumstances to which some speculators ascribe
the formation of sympathy at least contribute to
strengthen or impair, to contract or expand it.
It will appear, more conveniently, in the next
article, that the theory of sympathy has suffered
from the omission of these circumstances. For
the present, it is enough to observe how much
our compassion for various sorts of animals, and
our fellow-feeling with various races of men, are
proportioned to the resemblance which they bear
to ourselves, to the frequency of our intercourse
with them, and to other causes which, in the
opinion of some, afford evidence that sympathy
itself is dependent on a more general law.
2. Had Smith extended his view beyond the
mere play of sympathy itself, and taken into ac¬
count all its preliminaries, and accompaniments,
and consequences, it seems improbable that he
should have fallen into the great error of repre¬
senting the sympathies in their primitive state,
without undergoing any transformation, as con¬
tinuing exclusively to constitute the moral sen¬
timents. He is not content with teaching that
they are the roots out of which these sentiments
grow, the stocks on which they are grafted, the
elements of which they are compounded;—doc¬
trines to which nothing could be objected but
their unlimited extent. He tacitly assumes,
that if a sympathy in the beginning caused or
formed a moral approbation, so it must ever
continue to do. He proceeds like a geologist
who should tell us that the layers of this planet
had always been in the same state, shutting his
eyes to transition states and secondary forma¬
tions ; or like a chemist who should inform us
that no compound substance can possess new
qualities entirely different from those which be¬
long to its materials. His acquiescence in this
old and still general error is the more remark¬
able, because Mr Hume’s beautiful Dissertation
on the Passions3 had just before opened a strik¬
ing view of some of the compositions and de¬
compositions which render the mind of a formed
man as different from its original state, as the
organization of a complete animal is from the
condition of the first dim speck of vitality. It
is from this oversight (ill supplied by moral
rules, a loose stone in his building) that he has
exposed himself to objections founded on expe¬
rience, to which it is impossible to attempt any
answer. For it is certain that in many, nay in
most cases of moral approbation, the adult man
approves the action or disposition merely as
right, and with a distinct consciousness that no
process of sympathy intervenes between the
approval and its object. It is certain that an
unbiassed person would call it moral approbation,
only as far as it excluded the interposition of
any reflection between the conscience and the
mental state approved. Upon the supposition
of an unchanged state of our active principles,
it would follow that sympathy never had any
share in the greater part of them. Had he ad¬
mitted the sympathies to be only elements enter¬
ing into the formation of Conscience, their dis¬
appearance, or their appearance only as auxili-
1 There is some confusion regarding this point in Butler’s first sermon on Compassion. ^
2 The feelings of beauty, grandeur, and whatever else is comprehended under the name of Taste, form no exception, or
they do not lead to action, but terminate in delightful contemplation ; which constitutes the essential distinction between
them and the moral sentiments, to which, in some points of view, they may doubtless be likened.
* Essays and Treatises, vol. II.
DISSERTATION SECOND.
377
aries, after the mind is mature, would have
been no more an objection to his system, than
the conversion of a substance from a transi¬
tional to a permanent state is a perplexity to
the geologist. It would perfectly resemble the
destruction of qualities, which is the ordinary
effect of chemical composition.
3. The same error has involved him in an¬
other difficulty perhaps still more fatal. The
sympathies have nothing more of an imperative
character than any other emotions. They
attract or repel like other feelings, according to
their intensity. If, then, the sympathies con¬
tinue in mature minds to constitute the whole
of conscience, it becomes utterly impossible to
explain the character of command and suprem¬
acy, which is attested by the unanimous voice
of mankind to belong to that faculty, and to
form its essential distinction. Had he adopted
the other representation, it would be possible to
conceive, perhaps easy to explain, that con¬
science should possess a quality which belonged
to none of its elements.
4. It is to this representation that Smith’s
theory owes that unhappy appearance of ren¬
dering the rule of our conduct dependent on
the notions and passions of those who surround
us, of which the utmost efforts of the most re¬
fined ingenuity have not been able to divest it.
This objection or topic is often ignorantly urged;
the answers are frequently solid; hut to most
men they must always appear to be an ingeni¬
ous and intricate contrivance of cycles and epi¬
cycles, which perplex the mind too much to
satisfy it, and seem devised to evade difficulties
which cannot be solved. All theories which
treat conscience as built up by circumstances
inevitably acting on all human minds, are, in¬
deed, liable to somewhat of the same miscon¬
ception ; unless they place in the strongest light
(what Smith’s theory excludes) the total de¬
struction of the scaffolding which was neces¬
sary only to the erection of the building, after
the mind is adult and mature, and warn the
hastiest reader, that it then rests on its own
foundation alone.
5. The constant reference of our own dispo¬
sitions and actions to the point of view from
which they are estimated by others, seems to
he rather an excellent expedient for preserving
our impartiality, than a fundamental principle
of Ethics. But impartiality, which is no more
than a removal of some hinderance to right judg¬
ment, supplies no materials for its exercise, and
no ride, or even principle, for its guidance. It
nearly coincides with the Christian precept of
doing unto others as we would they should do
unto us; an admirable practical maxim, but, as
Leibnitz has said truly, intended only as a cor¬
rection of self-partiality.
6. Lastly, this ingenious system renders all
morality relative,—by referring it to the plea¬
sure of an agreement of our feelings with those
of others, by confining itself entirely to the
question of moral approbation, and by provid¬
ing no place for the consideration of that quality
which distinguishes all good from all bad ac¬
tions ;—a defect which will appear in the sequel
to be more immediately fatal to a theorist of the
sentimental, than to one of the intellectual school.
Smith shrinks from considering utility in that
light as soon as it presents itself, or very strange¬
ly ascribes its power over our moral feelings to
admiration of the mere adaptation of means
to ends,—which might surely be as well felt for
the production of wide-spread misery, by a con¬
sistent system of wicked conduct,—instead of
ascribing it to benevolence, with Hutcheson and
Hume, or to an extension of that very sympathy
which is his own first principle.
RICHARD PRICE.1
About the same time with the celebrated and eminent non-conformist minister, published
work of Smith, but with a popular reception A Beview of the principal Questions in Morals ;a—
very different, Dr Richard Price, an excellent an attempt to revive the intellectual theory of
1 Born in 1723; died in 1791. * The third edition was published at London in 1787-
O B
DiSS. II.
378
PRELIMINARY DISSERTATIONS.
moral obligation, which seemed to have fallen
under the attacks of Butler, Hutcheson, and
Hume, even before Smith. It attracted little
observation at first; but being afterwards coun¬
tenanced by the Scottish School, may seem to
deserve some notice, at a moment when the
kindred speculations of the German metaphysi¬
cians have effected an establishment in France,
and are no longer unknown in England.
The understanding itself is, according to
Price, an independent source of simple ideas.
“ The various kinds of agreement and disagree¬
ment between our ideas, spoken of by Locke,
are so many new simple ideas.” “ This is true
of our ideas of proportion, of our ideas of iden¬
tity and diversity, existence, connection, cause
and effect, power, possibility, and of our ideas
of right and wrong.” “ The first relates to
quantity, the last to actions, the rest to all
things.” “ Like all other simple ideas, they are
undefineable.”
It is needless to pursue this theory farther,
till an answer shall be given to the observation
made before, that as no perception or judgment,
or other unmixed act of understanding, merely
as such, and without the agency of some inter¬
mediate emotion, can affect the will, the account
given by Hr Price of perceptions or judgments
respecting moral subjects, does not advance one
step towards the explanation of the authority of
conscience over the will, which is the matter to
be explained. Indeed, this respectable writer
felt the difficulty so much as to allow, “ that in
contemplating the acts of moral agents, we have
both a perception of the understanding and a
feeling of the heart.” He even admits, that it
would have been highly pernicious to us if our
reason had been left without such support. But
he has not shown how, on such a supposition,
we could have acted on a mere opinion; nor
has he given any proof that what he calls sup¬
port is not, in truth, the whole of what directly
produces the conformity of voluntary acts to
morality.1 *
DAVID HARTLEY.*
The work of Dr Hartley, entitled Observations
on Man,3 is distinguished by an uncommon
union of originality with modesty, in unfolding
a simple and fruitful principle of human nature.
It is disfigured by the absurd affectation of ma¬
thematical forms then prevalent; and it is en¬
cumbered and deformed by a mass of physiolo¬
gical speculations, groundless, or at best uncer¬
tain, wholly foreign from its proper purpose,
which repel the inquirer into mental philosophy
from its perusal, and lessen the respect of the
physiologist for the author’s judgment. It is an
unfortunate example of the disposition predomi¬
nant among undistinguishing theorists to class
together all the appearances which are observed
at the same time, and in the immediate neigh¬
bourhood of each other. At that period, chemi¬
cal phenomena were referred to mechanical prin¬
ciples ; vegetable and animal life were subjected
to mechanical or chemical laws; and while some
physiologists4 ascribed the vital functions to the
understanding, the greater part of metaphysi¬
cians were disposed, with a grosser confusion,
to derive the intellectual operations from bodily
causes. The error in the latter case, though less
immediately perceptible, is deeper and more
fundamental than in any other; since it over¬
looks the primordial and perpetual distinction
between the being which thinks and the thing
which is thought of;—not to be lost sight of, by
the mind’s eye, even for a twinkling, without
involving all nature in darkness and confusion.
1 The following sentences will illustrate the text, and are in truth applicable to all moral theories on merely intellectual
principles :—“ Reason alone, did we possess it in a higher degree, would answer all the ends of the passions. Thus there
would he no need of parental affection, were all parents sufficiently acquainted with the reasons for taking upon them the
guidance and support of those whom nature has placed under their care, and -were they virtuous enough to be always determined
ly those reasons." (Price’s Review, 121.) A very slight consideration will show, that without the last words the preceding
part would be utterly false, and with them it is utterly insignificant.
* Born in 1705 ; died in 1757-
3 London, 1749.
4 G. E. Stahl, born in 1660; died in 1734; a German physician and chemist of deserved eminence.
DISSERTATION SECOND.
379
Hartley and Condillac,1 who, much about the
same time, hut seemingly without any know¬
ledge of each other’s speculations,2 * began in a
very similar mode to simplify, hut also to muti¬
late the system of Locke, stopped short of what
is called Materialism, which consummates the
confusion, hut touched its threshold. Thither,
it must be owned, their philosophy pointed, and
thither their followers proceeded. Hartley and
Bonnet,5 still more than Condillac, suffered them¬
selves, like most of their contemporaries, to
overlook the important truth, that all the changes
in the organs which can he likened to other
material phenomena, are nothing more than an¬
tecedents and prerequisites of perception, hearing
not the faintest likeness to it; as much outward
in relation to the thinking principle, as if they
occurred in any other part of matter; and of
which the entire comprehension, if it were at¬
tained, would not bring us a step nearer to the
nature of thought. They who would have been
the first to exclaim against the mistake of a
sound for a colour, fell into the more unspeak¬
able error of confounding the perception of ob¬
jects, as outward, with the consciousness of our
own mental operations. Locke’s doctrine, that
Reflection was a separate source of ideas, left
room for this greatest of all distinctions,—
though with much unhappiness of expression,
and with no little variance from the course of
his own speculations. Hartley, Condillac, and
Bonnet, in hewing away this seeming deformity
from the system of their master, unwittingly
struck off the part of the building which, how¬
ever unsightly, gave it the power of yielding
some shelter and guard to truths, of which the
exclusion rendered it utterly untenable. They
became consistent Nominalists; a controversy
on which Locke expresses himself with confu¬
sion and contradiction; but on this subject they
added nothing to what had been taught by
Hobbes and Berkeley. Both Hartley and Con¬
dillac4 have the merit of having been unseduced
by the temptations either of scepticism or of
useless idealism; which, even if Berkeley and
Hume could have been unknown to them, must
have been within sight. Both agree in referring
all the intellectual operations to the association
of ideas, and in representing that association as
reducible to the single law, that ideas which en¬
ter the mind at the same time, acquire a ten¬
dency to call up each other, which is in direct
proportion to the frequency of their having en¬
tered together. In this important part of their
doctrine they seem, whether unconsciously or
otherwise, to have only repeated, and very much
expanded, the opinion of Hobbes.5 In its sim¬
plicity it is more agreeable than the system of
Mr Hume, who admitted five independent laws
of association; and it is in comprehension far
superior to the views of the same subject by Mr
Locke, whose ill-chosen name still retains its
place in our nomenclature, but who only appeals
to the principle as explaining some fancies and
whimsies of the human mind. The capital fault
of Hartley is that of a rash generalization, which
may prove imperfect, and which is at least pre¬
mature. All attempts to explain instinct by this
principle have hitherto been unavailing. Many
of the most important processes of reasoning have
not hitherto been accounted for by it.6 It would
appear by a close examination, that even this
theory, simple as it appears, presupposes many
facts relating to the mind, of which its authors
1 Born in 1715 ; died in 1780.
2 Trait'z sur VOrigine des Connoissances Humames, 1746 ; Traite des Systemes, 1749 ; Traite des Sensations, 1754. Foreign
books were then little and slowly known in England. Hartley’s reading, except on theology, seems confined to the physi¬
cal and mathematical sciences; and his whole manner of thinking and writing is so different from that of Condillac, that
there is not the least reason to suppose the work of the one to have been known to the other.
The work of Hartley, as we learn from the sketch of his life by his son, prefixed to the edition of 1791, was begun in
1730, and finished in 1746.
* Born in 1720; died in 1793.
4 The following note of Condillac will show how much he differed from Hartley in his mode of considering the Newton¬
ian hypothesis of vibrations, and how far he was in that respect superior to him. “ Je suppose ici et ailleurs que les per¬
ceptions de Tame ont pour cause physique I’ebranlement des fibres du cerveau; non que je regarde cette hypothese comme de-
montrte, maxs parcequ' elle est la plus commode pour expliquer ma pcnsee.” {CEuvres de Condillac, I. 60. Paris, 1798.)
5 Human Nature, chap. iv. v. vi. For more ancient statements, see Notes and Illustrations, note T.
* “ Ce que les logiciens ont dit des raisonnements dans bien des volumes, me paroit entierement superflu, et de nul
usage” (Condillac, I. 115); an assertion of which the gross absurdity will be apparent to the readers of Dr Whately’s
Treatise on Logic, one of the most important works of the present age.
380
PRELIMINARY DISSERTATIONS.
do not seem to have suspected the existence.
How many ultimate facts of that nature, for ex¬
ample, are contained and involved in Aristotle s
celebrated comparison of the mind in its first
state to a sheet of unwritten paper!1 The tex¬
ture of the paper, even its colour, the sort of in¬
strument fit to act on it, its capacity to receive
and to retain impressions, all its differences,
from steel on the one hand to water on the
other, certainly presuppose some facts, and may
imply many, without a distinct statement of
which, the nature of writing could not be ex¬
plained to a person wholly ignorant of it. How
many more, as well as greater laws, may he ne¬
cessary to enable mind to perceive outward ob¬
jects ! If the power of perception may be thus
dependent, why may not what is called the asso¬
ciation of ideas, the attraction between thoughts,
the power of one to suggest another, he affected
by mental laws hitherto unexplored, perhaps un¬
observed ?
But to return from digression into the intel¬
lectual part of man : It becomes proper to say,
that the difference between Hartley and Con¬
dillac, and the immeasurable superiority of the
former, are chiefly to be found in the applica¬
tion which Hartley first made of the law of as¬
sociation to that other unnamed portion of our
nature with which morality more immediately
deals; that which feels pain and pleasure, is
influenced by appetites and loathings, by desires
and aversions, by affections and repugnances.
Condillac’s Treatise an Sensation, published five
years after the work of Hartley, reproduces the
doctrine of Hobbes with its root, namely, that
love and hope are but transformed sensations,2 3 4
by which he means perceptions of the senses;
and its wide-spread branches, consisting in de¬
sires and passions, which are only modifications
of self-love. 44 The words goodness and beauty,”
says he, almost in the very words of Hobbes,
44 express those qualities of things by which they
contribute to our pleasures.”5 In the whole of
his philosophical works, we find no trace of any
desire produced by association, of any disinter¬
ested principle, or indeed of any distinction be¬
tween the percipient and what, perhaps, we may
now venture to call the emotive or the pathematic
part of human nature, until some more conve¬
nient and agreeable name shall be hit on by
some luckier or more skilful adventurer, in such
new terms as seem to be absolutely necessary.
To the ingenuous, humble, and anxiously con¬
scientious character of Hartley, we owe the know¬
ledge that, about the year 1730, he was inform¬
ed that the Rev. Mr Gay of Sidney College,
Cambridge, then living in the west of England,
asserted the possibility of deducing all our intel¬
lectual pleasures and pains from association;
that this led him (Hartley) to consider the power
of association; and that about that time Mr Gay
published his sentiments on this matter in a dis¬
sertation prefixed to Bishop Law’s Translation of
King’s Origin of Evil.* No writer deserves more
the praise of abundant fairness than Hartley in
this avowal. The dissertation of which he speaks
is mentioned by no philosopher but himself. It
suggested nothing apparently to any other read¬
er. The general texture of it is that of home-
spun selfishness. The writer had the merit to
see and to own that Hutcheson had established
as a fact the reality of moral sentiments and dis¬
interested affections. He blames, perhaps just¬
ly, that most ingenious man,5 for assuming that
these sentiments and affections are implanted,
and partake of the nature of instincts. The ob¬
ject of his dissertation is to reconcile the mental
appearances described by Hutcheson with the
1 See Notes and Illustrations, note U.
2 Condillac, III. 21 ; more especially Traitc dcs Sensations, part ii. chap. vi. “ Its love for outward objects is only an
effect of love for itself.”
3 Traite des Sensations, part iv. chap. iii.
4 Hartley’s Preface to the Observations on Man. The word intellectual is too narrow. Even mental would be of very
doubtful propriety. The theory in its full extent requires a word such as inorganic, (if no better can be discovered) extend¬
ing to all gratification, not distinctly referred to some specific organ, or at least to some assignable part of the bodily frame.
5 It has not been mentioned in its proper place, that Hutcheson appears nowhere to greater advantage than in Letters
on the Fable of the Bees, published when he was very young, at Dublin, in a publication called Hibernicus. “ Private vices
public benefits,” says he, “ may signify any one of these five distinct propositions : 1. They are in themselves public be¬
nefits ; or, 2. They naturally produce public happiness ; or, 3. They may be made to produce it; or, 4, They may natu¬
rally flow from it; or, 5. At least they may probably flow from it in our infirm nature.” (See a small volume containing
Thoughts on Laughter, and Observations on the Fable of the Bees, Glasgow, 1758, in which these letters are republished.)
DISSERTATION SECOND.
381
first principle of the selfish system, that “ the
true principle of all our actions is our own hap¬
piness.” Moral feelings and social affections
are, according to him, “ resolvable into reason,
pointing out our private happiness; and when¬
ever this end is not perceived, they are to he ac¬
counted for from the association of ideas.” Even
in the single passage in which he shows a glimpse
of the truth, he begins with confusion, advances
with hesitation, and after holding in his grasp
for an instant the principle which sheds so
strong a light around it, suddenly drops it from
his hand. Instead of receiving the statements
of Hutcheson (his silence relating to Butler is
unaccountable) as enlargements of the science
of man, he deals with them merely as difficulties
to be reconciled with the received system of
universal selfishness. In the conclusion of his
fourth section, he well exemplifies the power of
association in forming the love of money, of
fame, of power, &c.; hut he still treats these
effects of association as aberrations and infirmi¬
ties, the fruits of our forgetfulness and short¬
sightedness, and not at all as the great process
employed to sow and rear the most important
principles of a social and moral nature.
This precious mine may therefore he truly
said to have been opened by Hartley; for he
who did such superabundant justice to the hints
of Gay, would assuredly not have withheld the
like tribute from Hutcheson, had he observ¬
ed the happy expression of “ secondary pas¬
sions,” which ought to have led that philoso¬
pher himself farther than he ventured to ad¬
vance. The extraordinary value of this part of
Hartley’s system has been hidden by various
causes, which have also enabled writers who
borrow from it to decry it. The influence of
his medical habits renders many of his examples
displeasing, and sometimes disgusting. He has
none of that knowledge of the world, of that fa¬
miliarity with literature, of that delicate percep¬
tion of the beauties of nature and art, which not
only supply the most agreeable illustrations of
mental philosophy, but afford the most obvious
and striking instances of its happy application to
subjects generally interesting. His particular
applications of the general law are often mis¬
taken, and seldom more than brief notes and
hasty suggestions; the germs of theories which,
while some might adopt them without detec¬
tion, others might discover without being aware
that they were anticipated. To which it may
he added, that in spite of the imposing forms of
geometry, the work is not really distinguished
by good method, or even uniform adherence to
that which had been chosen. His style is en¬
titled to no praise but that of clearness, and a
simplicity of diction, through which is visible a
singular simplicity of mind. No book perhaps
exists which, with so few of the common allure¬
ments, comes at last so much to please by the
picture it presents of the writer’s character,—a
character which kept him pure from the pursuit,
often from the consciousness of novelty, and ren¬
dered him a discoverer in spite of his own modes¬
ty. In those singular passages in which, amidst
the profound internal tranquillity of all the Euro¬
pean nations, he foretells approaching convul¬
sions, to he followed by the overthrow of states
and churches, his quiet and gentle spirit, else¬
where almost ready to inculcate passive obe¬
dience for the sake of peace, is supported under
its awful forebodings by the hope of that general
progress in virtue and happiness which he saw
through the preparatory confusion. A meek piety,
inclining towards mysticism, and sometimes in¬
dulging in visions which borrow a lustre from his
fervid benevolence, was beautifully, and perhaps
singularly, blended in him with zeal for the most
unbounded freedom of inquiry, flowing both
from his own conscientious belief and his un¬
mingled love of truth. Whoever can so far
subdue his repugnance to petty or secondary
faults as to bestow a careful perusal on the
work, must be unfortunate if he does not see,
feel, and own, that the writer was a great phi¬
losopher and a good man.
To those who thus study the work, it will be
apparent that Hartley, like other philosophers,
either overlooked, or failed explicitly to an¬
nounce, that distinction between perception and
emotion, without which no system of mental
philosophy is complete. Hence arose the partial
and incomplete view of truth conveyed by the
use of the phrase “ association of ideas.” If
the word association, which rather indicates the
connection between separate things, than th.e
382
PRELIMINARY DISSERTATIONS.
perfect combination and fusion which occur in
many operations of the mind, must, notwith¬
standing its inadequacy, still he retained, the
phrase ought at least tohe “association of thoughts
with emotions, as well as with each other.
With that enlargement an objection to the Hart-
leian doctrine would have been avoided, and its
originality, as well as superiority over that of
Condillac, would have appeared indisputable.
The examples of avarice and other factitious
passions are very well chosen; first, because few
will be found to suppose that they are original
principles of human nature ;1 secondly, because
the process by which they are generated, being
subsequent to the age of attention and recollec¬
tion, may be brought home to the understanding
of all men ; and, thirdly, because they afford the
most striking instance of secondary passions,
which not only become independent of the pri¬
mary principles from which they are derived,
but hostile to them, and so superior in strength
as to be capable of overpowering their parents.
As soon as the mind becomes familiar with the
frequent case of the man who first pursued money
to purchase pleasure, but at last, when he be¬
comes a miser, loves his hoard better than all
that it could purchase, and sacrifices all pleasures
for its increase, we are prepared to admit that,
by a like process, the affections, when they are
fixed on the happiness of others as their ultimate
object, without any reflection on self, may not
only be perfectly detached from self-regard or
private desires, but may subdue these, and every
other antagonist passion which can stand in
their way. As the miser loves money for its
own sake, so may the benevolent man delight in
the wellbeing of his fellows. His good-will be¬
comes as disinterested as if it had been implant¬
ed and underived. The like process applied to
what is called self-love, or the desire of perma¬
nent wellbeing, clearly explains the mode in
which that principle is gradually formed from
the separate appetites, without whose previous
existence no notion of wellbeing could be ob¬
tained. In like manner, sympathy, perhaps it¬
self the result of a transfer of our own personal
feelings by association to other sentient beings,
and of a subsequent transfer of their feelings to
our own minds, engenders the various social af¬
fections, which at last generate in most minds
some regard to the wellbeing of our country, of
mankind, of all creatures capable of pleasure.
Rational self-love controls and guides those far
keener self-regarding passions of which it is the
child, in the same manner as general benevo¬
lence balances and governs the variety of much
warmer social affections from which it springs.
It is an ancient and obstinate error of philoso¬
phers to represent these two calm principles as
being the source of the impelling passions and
affections, instead of being among the last re¬
sults of them. Each of them exercises a sort
of authority in its sphere, but the dominion of
neither is co-existent with the whole nature of
man. Though they have the power to quicken
and check, they are both too feeble to impel;
and if the primary principles were extinguished,
they would both perish from want of nourish¬
ment. If indeed all appetites and desires were
destroyed, no subject would exist on which either
of these general principles could act.
The affections, desires, and emotions, having for
their ultimate object the dispositions and actions
of voluntary agents, which alone, from the nature
of their object, are co-extensive with the whole
of our active nature, are, according to the same
philosophy, necessarily formed in every human
mind by the transfer of feeling which is effected
by the principle of association. Gratitude, pity,
resentment, and shame, seem to be the simplest,
the most active, and the most uniform elements
in their composition.
It is easy to perceive how the complacency
inspired by a benefit may be transferred to a
benefactor, thence to all beneficent beings and
acts. The well-chosen instance of the nurse
familiarly exemplifies the manner in which the
child transfers his complacency from the grati¬
fication of his senses to the cause of it, and thus
learns an affection for her who is the source of
1 A very ingenious man, Lord Kames, whose works had a great effect in rousing the mind of his contemporaries and
countrymen, has indeed fancied that there is “ a hoarding instinct” in man and other animals. But such conclusions are
not so much objects of confutation, as ludicrous proofs of the absurdity of the premises which lead to them.
DISSERTATION SECOND.
383
his enjoyment. With this simple process con¬
cur, in the case of a tender nurse, and far more
of a mother, a thousand acts of relief and en¬
dearment, of which the complacency is fixed on
the person from whom they flow, and in some
degree extended by association to all who re¬
semble that person. So much of the pleasure
of early life depends on others, that the like pro¬
cess is almost constantly repeated. Hence the
origin of benevolence may be understood, and
the disposition to approve all benevolent, and
disapprove all malevolent acts. Hence also the
same approbation and disapprobation are ex¬
tended to all acts which we clearly perceive to
promote or obstruct the happiness of men.
When the complacency is extended to action,
benevolence may be said to be transformed into
a part of conscience. The rise of sympathy
may probably be explained by the process of
association, which transfers the feelings of others
to ourselves, and ascribes our own feelings to
others;—at first, and in some degree, always
in proportion as the resemblance of ourselves to
others is complete. The likeness in the outward
signs of emotion is one of the widest channels
in this commerce of hearts. Pity thereby be¬
comes one of the grand sources of benevolence,
and perhaps contributes more largely than gra¬
titude. It is indeed one of the first motives to
the conferring of those benefits which inspire
grateful affection. Sympathy with the sufferer,
therefore, is also transformed into a real senti¬
ment, directly approving benevolent actions and
dispositions, and more remotely all actions that
promote happiness. The anger of the sufferer,
first against all causes of pain, afterwards against
all intentional agents who produce it, and final¬
ly against all those in whom the infliction of
pain proceeds from a mischievous disposition,
when it is communicated to others by sympathy,
and is so far purified by gradual separation from
selfish and individual interest as to be equally
felt against all wrong-doers, whether the wrong
be done against ourselves, our friends, or our
enemies, is the root out of which springs that
which is commonly and well called a Sense of
Justice—the most indispensable, perhaps, of all
the component parts of the moral faculties. It
is the main guard against wrong. It relates to
that portion of morality where many of the out¬
ward acts are capable of being reduced under
certain rules, of which the violations, wherever
the rule is sufficiently precise, and the mischief
sufficiently great, may be guarded against by
the terror of punishment. In the observation
of the rules of justice consists duty ; breaches of
them we denominate crimes. An abhorrence of
crimes, especially of those which indicate the
absence of benevolence, as well as of regard to
justice, is peculiarly strong; because well-framed
penal laws, being the lasting declaration of the
moral indignation of many generations of man¬
kind, exceedingly strengthen the same feeling
in every individual, as long as they remain in
unison with the sentiments of the age and coun¬
try for which they are destined, and, indeed,
wherever the laws do not so much deviate
from the habitual feelings as to produce a
struggle between law and sentiment, in which
it is hard to say on which side success is most
deplorable. A man who performs his duties
may be esteemed, but is not admired; because
it requires no more than ordinary virtue to act
well where it is shameful and dangerous to do
otherwise. The righteousness of those who act
solely from such inferior motives, is little better
than that “of the Scribes and Pharisees.” Those
only are just in the eye of the moralist who act
justly from a constant disposition to render to
every man his own.1 Acts of kindness, of gene¬
rosity, of pity, of placability, of humanity, when
they are long continued, can hardly fail mainly
to flow from the pure fountain of an excellent
nature. They are not reducible to rules; and
the attempt to enforce them by punishment
would destroy them. They are virtues of which
the essence consists in a good disposition of
mind. As we gradually transfer our desire from
praise to praiseworthiness, this principle also is
adopted into consciousness. On the other hand,
1 “ Justitia est constans et perpetua voluntas suum cuique tribuendi;” an excellent definition in the mouth of the Stoical
moralists, from whom it is borrowed, but altogether misplaced by the Roman Jurists in a body of laws which deal only with
outward acts in their relation to the order and interest of society.
384
PRELIMINARY DISSERTATIONS.
when we are led by association to feel a painful
contempt for those feelings and actions of our
past self which we despise in others, there is
developed in our hearts another element of that
moral sense. It is a remarkable instance of the
power of the law of association, that the con¬
tempt or abhorrence which we feel for the bad
actions of others may he transferred by it, in any
degree of strength, to our own past actions of the
like kind. And as the hatred of had actions is
transferred to the agent, the same transfer may
occur in our own case in a manner perfectly
similar to that of which we are conscious in our
feelings towards our fellow-creatures. There are
many causes which render it generally feebler;
but it is perfectly evident that it requires no more
than a sufficient strength of moral feeling to
make it equal; and that the most apparently
hyperbolical language used by penitents, in de¬
scribing their remorse, may be justified by the
principle of association.
At this step in our progress, it is proper to ob¬
serve, that a most important consideiation has
escaped Hartley, as well as every other philoso¬
pher. 1 The language of all mankind implies that
the moral faculty, whatever it may be, and from
what origin soever it may spring, is intelligibly
and properly spoken of as One. It is as com¬
mon in mind as in matter for a compound to
have properties not to be found in any of its con¬
stituent parts. The truth of this proposition is
as certain in the human feelings as in any ma¬
terial combination. It is therefore easily under¬
stood, that originally separate feelings may be so
perfectly blended by a process performed in every
mind, that they can no longer be disjoined from
each other, but must always co-operate, and thus
reach the only union which we can conceive.
The sentiment of Moral Approbation, formed by
association out of antecedent affections, may be¬
come so perfectly independent of them, that we
are no longer conscious of the means by which
it was formed, and never can in practice repeat,
though we may in theory perceive, the process
by which it was generated. It is in that mature
and sound state of our nature that our emotions
at the view of Right and Wrong are ascribed to
Conscience. But why, it may be asked, do these
feelings, rather than others, run into each other,
and constitute Conscience ? The answer seems
to be what has already been intimated in the ob¬
servations on Butler. The affinity between these
feelings consists in this, that while all other
feelings relate to outward objects, they alone
contemplate exclusively the dispositions and
actions of voluntary agents. When they are
completely transferred from objects, and even
persons, to dispositions and actions, they are
fitted, by the perfect coincidence of their aim, for
combining to form that one faculty which is di¬
rected only to that aim.
The words Duty and Virtue, and the word
Ought, which most perfectly denotes Duty, but is
also connected with Virtue, in every well-consti¬
tuted mind, in this state become the fit language
of the acquired, perhaps, but universally and ne¬
cessarily acquired, faculty of Conscience. Some
account of its peculiar nature has been attempted
in the remarks on Butler;—for others a fitter oc¬
casion will occur hereafter. Some light may how¬
ever now he thrown on the subject by a short state¬
ment of the hitherto unobserved distinction be¬
tween the moral sentiments and another class of
feelings with which they have some qualities in
common. The pleasures (so called) of Imagina¬
tion appear, at least in most cases, to originate in
association. But it is not till the original cause of
the gratification is obliterated from the mind, that
they acquire their proper character. Order and
proportion may be at first chosen for their con¬
venience : it is not until they are admired for
their own sake that they become objects of taste.
Though all the proportions for which a horse
is valued may be indications of speed, safety,
strength, and health, it is not the less true that
they only can be said to admire the animal for
his beauty, who leave such considerations out of
the account while they admire. The pleasure of
contemplation in these particulars of nature and
art becomes universal and immediate, being
entirely detached from all regard to individual
beings. It contemplates neither use nor interest.
1 See tujpra, section on Butler.
DISSERTATION SECOND.
385
In this important particular the pleasures of
imagination agree with the moral sentiments.
Hence the application of the same language to
both in ancient and modern times. Hence also
it arises that they may contemplate the very
same qualities and objects. There is certainly
much beauty in the softer virtues—much gran¬
deur in the soul of a Hero or a Martyr. But
the essential distinction still remains. The
purest moral taste contemplates these qualities
only with quiescent delight or reverence. It has
no further view;—it points towards no action.
Conscience, on the contrary, containing in it a
pleasure in the prospect of doing right, and an
ardent desire to act well, having for its sole
object the dispositions and acts of voluntary
agents, is not, like moral taste, satisfied with
passive contemplation, but constantly tends to
act on the will and conduct of the man. Moral
taste may aid it, may be absorbed into it, and
usually contributes its part to the formation of
the moral faculty; but it is distinct from that
faculty, and may be disproportioned to it. Con¬
science, being by its nature confined to mental
dispositions and voluntary acts, is of necessity
excluded from the ordinary consideration of all
things antecedent to these dispositions. The
circumstances from which such states of mind
may arise, are most important objects of con¬
sideration for the understanding; but they are
without the sphere of conscience, which never
ascends beyond the heart of the man. It is thus
that in the eye of conscience man becomes ame¬
nable to its authority for all his inclinations as
well as deeds; that some of them are approved,
loved, and revered; and that all the outward
effects of disesteem, contempt, or moral anger,
are felt to be the just lot of others.
But, to return to Hartley, from this perhaps
intrusive statement of what does not properly
belong to him: He represents all the social af¬
fections of gratitude, veneration, and love, in¬
spired by the virtues of our fellow-men, as ca¬
pable of being transferred by association to the
transcendent and unmingled goodness of the
Ruler of the world, and thus to give rise to
piety, to which he gives the name of the theopa-
thetic affection. This principle, like all the for¬
mer in the mental series, is gradually detached
mss. ii.
from the trunk on which it grew: it takes sepa¬
rate root, and may altogether overshadow the
parent stock. As such a being cannot be con¬
ceived without the most perfect and constant re¬
ference to his goodness, so piety may not only
become a part of conscience, but its governing
and animating principle, which, after long lend¬
ing its own energy and authority to every other,
is at last described by our philosopher as swal¬
lowing up all of them in order to perform the
same functions more infallibly.
In every stage of this progress we are taught
by Dr Hartley that a new product appears,
which becomes perfectly distinct from the ele¬
ments which formed it, which may be utterly
dissimilar to them, and may attain any degree
of vigour, however superior to theirs. Thus the
objects of the private desires disappear when we
are employed in the pursuit of our lasting wel¬
fare; that which was first sought only as a means,
may come to be pursued as an end, and prefer¬
red to the original end; the good opinion of our
fellows becomes more valued than the benefits
for which it was at first courted ; a man is ready
to sacrifice his life for him who has shown ge¬
nerosity, even to others ; and persons otherwise
of common character are capable of cheerfully
marching in a forlorn hope, or of almost instinc¬
tively leaping into the sea to save the life of an
entire stranger. These last acts, often of almost
unconscious virtue, so familiar to the soldier and
the sailor, so unaccountable on certain systems
of philosophy, often occur without a thought of
applause and reward; too quickly for the thought
of the latter, too obscurely for the hope of the
former; and they are of such a nature that no
man could be impelled to them by the mere ex¬
pectation of either.
The gratitude, sympathy, resentment, and
shame, which are the principal constituent parts
of the Moral Sense, thus lose their separate
agency, and constitute an entirely new faculty,
co-extensive with all the dispositions and actions
of voluntary agents; though some of them are
more predominant in particular cases of moral
sentiment than others, and though the aid of all
continues to be necessary in their original cha¬
racter, as subordinate but distinct motives of ac¬
tion. Nothing more evidently points out the
3 0
386
PRELIMINARY DISSERTATIONS.
distinction of the Hartleian system from all sys¬
tems called selfish, not to say its superiority in
respect to disinterestedness over all moral sys¬
tems before Butler and Hutcheson, than that
excellent part of it which relates to the Rule of
Life. The various principles of human action
rise in value according to the order in which
they spring up after each other. We can then
only be in a state of as much enjoyment as we
are evidently capable of attaining, when we
prefer interest to the original gratifications—
honour to interest—the pleasures of imagination
to those of sense—the dictates of conscience to
pleasure, interest, and reputation—the well¬
being of fellow-creatures to our own indulgences;
in a word, when we pursue moral good and
social happiness chiefly and for their own sake.
“ With self-interest,” says Hartley, somewhat
inaccurately in language, “ man must begin.
He may end in self-annihilation. Theopathy, or
piety, although the last result of the purified and
exalted sentiments, may at length swallow up
every other principle, and absorb the whole
man.” Even if this last doctrine should he
an exaggeration unsuited to our present con¬
dition, it will the more strongly illustrate the
compatibility, or rather the necessary connec¬
tion, of this theory with the existence and power
of perfectly disinterested principles of human
action.
It is needless to remark on the secondary and
auxiliary causes which contribute to the forma¬
tion of moral sentiment; education, imitation,
general opinion, laws and government. They
all presuppose the moral faculty: in an improved
state of society they contribute powerfully to
strengthen it, and on some occasions they en¬
feeble, distort, and maim it; but in all cases
they must themselves be tried by the test of an
ethical standard.
The value of this doctrine will not he essen¬
tially affected by supposing a greater number
of original principles than those assumed by Dr
Hartley. The principle of association applies as
much to a greater as to a smaller number. It
is a quality common to it with all theories, that
the more simplicity it reaches consistently with
truth, the more perfect it becomes. Causes are
not to be multiplied without necessity. If by a
considerable multiplication of primary desires
the law of association were lowered nearly to
the level of an auxiliary agent, the philosophy
of human nature would still be under indelible
obligations to the philosopher who, by his for¬
tunate error, rendered the importance of that
great principle obvious and conspicuous.
ABRAHAM TUCKER.1 2 * * * *
It has been the remarkable fortune of this
writer to have been more prized by the culti¬
vators of the same subjects, and more disregard¬
ed by the generality even of those who read
books on such matters, than perhaps any other
philosopher.8 He had many of the qualities
which might he expected in an affluent country
gentleman, living in a privacy undisturbed by
political zeal, and with a leisure unbroken by
the calls of a profession, at a time when Eng¬
land had not entirely renounced her old taste
for metaphysical speculation. He was naturally
endowed, not indeed with more than ordinary
acuteness or sensibility, nor with a high degree
of reach and range of mind, hut with a singular
capacity for careful observation and original re¬
flection, and with a fancy perhaps unmatched in
producing various and happy illustration. The
most observable of his moral qualities appear to
have been prudence and cheerfulness, good-na¬
ture and easy temper. The influence of his si¬
tuation and character is visible in his writings.
Indulging his own tastes and fancies, like most
English squires of his time, he became, like
1 Born in 1705; died in 1774.
2 “ I have found in this writer more original thinking and observation upon the several subjects that he has taken in
hand than in any other, not to say than in all others put together. His talent also for illustration is unrivalled.” (Paley,
Preface to Moral and Political Philosophy.) See the excellent preface to an abridgement, by Mr Hazlitt, of Tucker’s work,
published in London in 1807. May I venture to refer also to my own discourse on the Law of Nature and Nations, London,
1799. Mr Stewart treats Tucker and Hartley with unwonted harshness.
DISSERTATION SECOND.
387
many of them, a sort of humourist. Hence
much of his originality and independence; hence
the boldness with which he openly employs il¬
lustrations from homely objects. He wrote to
please himself more than the public. He had
too little regard for readers, either to sacrifice
his sincerity to them, or to curb his own pro¬
lixity, repetition, and egotism, from the fear of
fatiguing them. Hence he became as loose, as
rambling, and as much an egotist as Montaigne;
but not so agreeably so, notwithstanding a con¬
siderable resemblance of genius; because he
wrote on subjects where disorder and egotism
are unseasonable, and for readers whom they
disturb instead of amusing. His prolixity at
last increased itself, when his work became so
long, that repetition in the latter parts partly
arose from forgetfulness of the former; and
though his freedom from slavish deference to
general opinion is very commendable, it must be
owned, that his want of a wholesome fear of the
public renders the perusal of a work which is
extremely interesting, and even amusing in most
of its parts, on the whole a laborious task. He
was by early education a believer in Chi’istian-
ity, if not by natural character religious. His
calm good sense and accommodating temper led
him rather to explain established doctrines in a
manner agreeable to his philosophy, than to as¬
sail them. Hence he was represented as a time¬
server by free-thinkers, and as a heretic by the
orthodox.1 Living in a country where the se¬
cure tranquillity flowing from the Revolution
was gradually drawing forth all mental activity
towards practical pursuits and outward objects,
he hastened from the rudiments of mental and
moral philosophy, to those branches of it which
touch the business of men.2 Had he recast
without changing his thoughts,—had he de¬
tached those ethical observations for which he
had so peculiar a vocation, from the disputes of
his country and his day,—he might have thrown
many of his chapters into their proper form of
essays, which might have been compared, though
not likened, to those of Hume. But the coun¬
try gentleman, philosophic as he was, had too
much fondness for his own humours to engage
in a course of drudgery and deference. It may,
however, be confidently added, on the authority
of all those who have fairly made the experi¬
ment, that whoever, unfettered by a previous
system, undertakes the labour necessary to dis¬
cover and relish the high excellencies of this
metaphysical Montaigne, will find his toil light¬
ened as he proceeds, by a growing indulgence,
if not partiality, for the foibles of the humourist;
and at last rewarded, in a greater degree per¬
haps than by any other writer on mixed and
applied philosophy, by being led to commanding
stations and new points of view, whence the
mind of a moralist can hardly fail to catch some
fresh prospects of nature and duty.
It is in mixed, not in pure philosophy, that
his superiority consists. In the part of his
work which relates to the intellect, he has
adopted much from Hartley, hiding but ag¬
gravating the offence by a change of technical
terms; and he was ungrateful enough to coun¬
tenance the vulgar sneer which involves the
mental analysis of that philosopher in the ridi¬
cule to which his physiological hypothesis is
liable.3 Thus, for the Hartleian term Associa¬
tion he substitutes that of Translation, when he
adopts the same theory of the principles which
move the mind to action. In the practical and
applicable part of that inquiry he indeed far
surpasses Hartley; and it is little to add, that
he unspeakably exceeds that bare and naked
thinker in the useful as well as admirable facul¬
ty of illustration. In the strictly theoretical
1 This disposition to compromise and accommodation, which is discoverable in Paley, was carried to its utmost length by
Mr Hey, a man of much acuteness, Professor of Divinity at Cambridge.
2 Perhaps no philosopher ever stated more justly, more naturally, or more modestly than Tucker, the ruling maxim of
his life. “ My thoughts,” says he, “ have taken a turn from my earliest youth towards searching into the foundations and
measures of right and wrong; my love for retirement has furnished me with continual leisure; and the exercise of my
reason has been my daily employment.”
3 Light of Nature, I. c. xviii. of which the conclusion may be pointed out as a specimen of perhaps unmatched fruitfulness,
vivacity, and felicity of illustration. The admirable sense of the conclusion of chap. xxv. seems to have suggested Paley s
good chapter on Happiness. The alteration of Plato’s comparison of reason to a charioteer, and the passions to the horses,
in chap. xxvi. is of characteristic and transcendent excellence.
388
PRELIMINARY DISSERTATIONS.
part his exposition is considerably fuller; but
the defect of his genius becomes conspicuous
when he handles a very general principle. The
very term Translation ought to have kept up in
his mind a steady conviction that the secondary
motives to action become as independent, and
seek their own objects as exclusively, as the
primary principles. His own examples are rich
in proofs of this important truth. But there is
a slippery descent in the Theory of Human Na¬
ture, by which he, like most of his forerunners,
slid unawares into selfishness. He was not pre¬
served from this fall by seeing that all the deli¬
berate principles which have self for their object
are themselves of secondary formation; and he
was led to the general error by the notion that
Pleasure, or, as he calls it, Satisfaction, was the
original and sole object of all appetites and de¬
sires ; confounding this with the true but very
different proposition, that the attainment of all
the objects of appetite and desire is productive
of pleasure. He did not see that, without pre¬
supposing Desires, the word Pleasure would
have no signification ; and that the representa.
tions by which he was seduced would leave only
one appetite or desire in human nature. He had
no adequate and constant conception, that the
translation of Desire from the end to the means
occasioned the formation of a new passion,
which is perfectly distinct from, and altogether
independent of, the original desire. Too fre¬
quently (for he was neither obstinate nor uni¬
form in error) he considered these translations
as accidental defects in human nature, not as
the appointed means of supplying it with its
variety of active principles. He was too apt
to speak as if the selfish elements were not de¬
stroyed in the new combination, but remain¬
ed still capable of being recalled, when conve¬
nient, like the links in a chain of reasoning,
which we pass over from forgetfulness, or for
brevity. Take him all in all, however, the
neglect of his writings is the strongest proof
of the disinclination of the English nation,
for the last half century, to Metaphysical Phi¬
losophy. 1
WILLIAM PALEY.2
This excellent writer, who, after Clarke and
Butler, ought to be ranked among the brightest
ornaments of the English church in the eigh¬
teenth century, is, in the history of philosophy,
naturally placed after Tucker, to whom, with
praiseworthy liberality, he owns his extensive
obligations. It is a mistake to suppose that he
owed his system to Hume, a thinker too refined,
and a writer perhaps too elegant, to have natu¬
rally attracted him. A coincidence in the prin¬
ciple of utility, common to both with so many
other philosophers, affords no sufficient ground
for the supposition. Had he been habitually in¬
fluenced by Mr Hume, who has translated so
many of the dark and crabbed passages of But¬
ler into his own transparent as well as beautiful
language, it is not possible to suppose that such
a mind as that of Paley should have fallen into
those principles of gross selfishness of which Mr
Hume is a uniform and zealous antagonist.
The natural frame of Paley’s understanding
fitted it more for business and the world than
for philosophy; and he accordingly enjoyed
with considerable relish the few opportunities
which the latter part of his life afforded of tak¬
ing a part in the affairs of his county as a ma¬
gistrate. Penetration and shrewdness, firm¬
ness and coolness, a vein of pleasantry, fruitful
though somewhat unrefined, with an original
homeliness and significancy of expression, were
1 Much of Tucker’s chapter on Pleasure, and of Paley’s on Happiness (both of which are invaluable), is contained in the
passage of The Traveller, of which the following couplet expresses the main object:
“ Unknown to them when sensual pleasures cloy,
“ To fill the languid pause with finer joy.” . . „
“ An honest man,” says Mr Hume, “ has the frequent satisfaction of seeing knaves betrayed by their own maxims.
(Enquiry into Morals.) ,
“ I used often to laugh at your honest simple neighbour Flamborough, and one way or another generally cheated him once
a year. Yet still the honest man went forward without suspicion, and grew rich, while I still continued tricksy and cun¬
ning, and was poor, without the consolation of being honest.” (Vicar of Wakefield, chap, xxvi.)
*”llorn in 1743 ; died in 1805.
DISSERTATION SECOND.
389
perhaps more remarkable in his conversation
than the restraints of authorship and profession
allowed them to be in his writings. Grateful
remembrance brings this assemblage of qualities
with unfaded colours before the mind at the
present moment, after the long interval of twen¬
ty-eight years. His taste for the common busi¬
ness and ordinary amusements of life fortunate¬
ly gave a zest to the company which his neigh¬
bourhood chanced to yield, without rendering
him insensible to the pleasures of intercourse
with more enlightened society. The practical
bent of his nature is visible in the language of
his writings, which, on practical matters, is as
precise as the nature of the subject requires,
but, in his rare and reluctant efforts to rise to
first principles, becomes indeterminate and un¬
satisfactory ; though no man’s composition was
more free from the impediments which hinder a
writer’s meaning from being quickly and clearly
seen. He seldom distinguishes more exactly
than is required for palpable and direct useful¬
ness. He possessed that chastised acuteness of
discrimination, exercised on the affairs of men,
and habitually looking to a purpose beyond the
mere increase of knowledge, which forms the
character of a lawyer’s understanding, and
which is apt to render a mere lawyer too subtile
for the management of affairs, and yet too gross
for the pursuit of general truth. His style is as
near perfection in its kind as any in our lan¬
guage. Perhaps no words were ever more ex¬
pressive and illustrative than those in which he
represents the art of life to be that of rightly
“ setting our habits.”
The most original and ingenious of his writ¬
ings is the Horce Paulina. The Evidences of
Christianity are formed out of an admirable
translation of Butler’s Analogy^ and a most skil¬
ful abridgement of Lardner’s Credibility of the
Gospel History. He may be said to have thus
given value to two works, of which the first was
scarcely intelligible to most of those who were
most desirous of profiting by it; and the second
soon wearies out the greater part of readers,
though the few who are more patient have al¬
most always been gradually won over to feel
pleasure in a display of knowledge, probity,
charity, and meekness, unmatched by an avow¬
ed advocate in a case deeply interesting his
warmest feelings. His Natural Theology is the
wonderful work of a man who, after sixty, had
studied anatomy in order to write it; and it
could only have been surpassed by a man who,
to great originality of conception and clearness
of exposition, added the advantage of a high
place in the first class of physiologists.1
It would be unreasonable here to say much of
a work which is in the hands of so many as his
Moral and Political Philosophy. A very few re¬
marks on one or two parts of it may be suffi¬
cient to estimate his value as a moralist, and to
show his defects as a metaphysician. His ge¬
neral account of virtue may indeed be chosen
for both purposes. The manner in which he
deduces the necessary tendency of all virtuous
actions to the general happiness, from the good¬
ness of the Divine Lawgiver, though the prin¬
ciple be not, as has already more than once ap¬
peared, peculiar to him, but rather common to
most religious philosophers, is characterized by
a clearness and vigour which have never been
surpassed. It is indeed nearly, if not entirely,
an identical proposition, that a Being of unmixed
benevolence will prescribe those laws only to his
creatures which contribute to their wellbeing.
When we are convinced that a course of conduct
is generally beneficial to all men, we cannot
help considering it as acceptable to a benevo¬
lent Deity. The usefulness of actions is the
mark set on them by the Supreme Legislator,
by which reasonable beings discover it to be His
will that such actions should be done. In this
apparently unanswerable deduction it is partly
admitted, and universally implied, that the prin¬
ciples of right and wrong may be treated apart
from the manifestation of them in the Scriptures.
If it were otherwise, how could men of perfectly
different religions deal or reason with each other
on moral subjects? How could they regard
rights and duties as subsisting between them ?
To what common principles could they appeal
1 See Animal Mechanics, by Mr Charles Bell, published by the Society for Useful Knowledge.
390
PRELIMINARY DISSERTATIONS.
in their differences ? Even the Polytheists them¬
selves, those worshippers of
Gods partial, changeful, passionate, unjust,
Whose attributes are rage, revenge, or lust,
by a happy inconsistency are compelled, how¬
ever irregularly and imperfectly, to ascribe
some general enforcement of the moral code to
their divinities. If there were no foundation
for morality antecedent to revealed religion, we
should want that important test of the conformi¬
ty of a revelation to pure morality, by which its
claim to a divine origin is to be tried. The in¬
ternal evidence of religion necessarily presup¬
poses such a standard. The Christian contrasts
the precepts of the Koran with the pure and
benevolent morality of the Gospel. The Maho¬
metan claims, with justice, a superiority over
the Hindoo, inasmuch as the Mussulman reli¬
gion inculcates the moral perfection of one Su¬
preme Ruler of the world. The ceremonial and
exclusive character of Judaism has ever been
regarded as an indication that it was intend¬
ed to pave the way for a universal religion,—a
morality seated in the heart, and a worship of
sublime simplicity. These discussions would
be impossible, unless morality were previously
proved or granted to exist. Though the science
of Ethics is thus far independent, it by no means
follows that there is any equality, or that
there may not be the utmost inequality, in the
moral tendency of religious systems. The most
ample scope is still left for the zeal and activity
of those who seek to spread important truth.
But it is absolutely essential to ethical science
that it should contain principles, the authority
of which must be recognised by men of every
conceivable variety of religious opinion.
The peculiarities of Paley’s mind are dis¬
coverable in the comparison, or rather contrast,
between the practical chapter on Happiness, and
the philosophical portion of the chapter on Vir¬
tue. “ Virtue is the doing good to mankind, in
obedience to the will of God, and for the sake
of everlasting happiness.”1 It is not perhaps
very important to observe, that these words,
which he offers as “ a definition,” ought in pro¬
priety to have been called a proposition; but
it is much more necessary to say that they con¬
tain a false account of virtue. According to
this doctrine, every action not done for the sake
of the agent’s happiness is vicious. Now, it is
plain that an act cannot be said to be done for
the sake of any thing which is not present to
the mind of the agent at the moment of action.
It is a contradiction in terms to affirm that a
man acts for the sake of any object, of which,
however it may be the necessary consequence of
his act, he is not at the time fully aware. The
unfelt consequences of his act can no more in¬
fluence his will than its unknown consequences.
Nay, further, a man is only with any propriety
said to act for the sake of his chief object; nor
can he with entire correctness be said to act for
the sake of any thing but his sole object. So
that it is a necessary consequence of Paley’s
proposition, that every act which flows from
generosity or benevolence is a vice. So also of
every act of obedience to the will of God, if it
arises from any motive but a desire of the re¬
ward which he will bestow. Any act of obe¬
dience influenced by gratitude, and affection,
and veneration towards supreme benevolence
and perfection, is so far imperfect; and if it
arises solely from these motives it becomes a
vice. It must be owned, that this excellent and
most enlightened man has laid the foundations
of religion and virtue in a more intense and ex¬
clusive selfishness than was avowed by the Ca¬
tholic enemies of Fenelon, when they persecuted
him for his doctrine of a pure and disinterested
love of God.
In another province, of a very subordinate
kind, the disposition of Paley to limit his princi¬
ples to his own time and country, and to look at
them merely as far as they are calculated to
amend prevalent vices and errors, betrayed him
into narrow and false views. His chapter on
what he calls the Law of Honour is unjust, even
in its own small sphere, because it supposes ho¬
nour to allow what it does not forbid; though the
truth be, that the vices enumerated by him are
only not forbidden by honour, because they are
1 Paley, book i. chap. vii.
DISSERTATION SECOND.
391
not within its jurisdiction. He considers it as
“ a system of rules constructed by people of
fashion—a confused and transient mode of
expression, which may he understood with diffi¬
culty by our posterity, and which cannot now be
exactly rendered perhaps in any other language.
The subject, however, thus narrowed and low¬
ered, is neither unimportant in practice, nor un¬
worthy of the consideration of the moral philo¬
sopher. Though all mankind honour virtue and
despise vice, the degree of respect or contempt is
often far from being proportioned to the place
which virtues and vices occupy in a just system
of Ethics. Wherever higher honour is bestowed
on one moral quality than on others of equal or
greater moral value, what is called a point of ho¬
nour may he said to exist. It is singular that so
shrewd an observer as Paley should not have
observed a law of honour far more permanent
than that which attracted his notice, in the feel¬
ings of Europe respecting the conduct of men
and women. Cowardice is not so immoral as
cruelty, nor indeed so detestable, hut it is more
despicable and disgraceful. The female point of
honour forbids indeed a great vice, but one not
so great as many others by which it is not vio¬
lated. It is easy enough to see, that where we
are strongly prompted to a virtue by a natural
impulse, we love the man who is constantly ac¬
tuated by the amiable sentiment, but we do not
consider that which is done without difficulty as
requiring or deserving admiration and distinc¬
tion. The kind affections are their own rich re¬
ward, and they are the object of affection to
others. To encourage kindness by praise would
be to insult it, besides its effect in producing
counterfeits. It is for the conquest of fear, it
would be still more for the conquest of resent¬
ment, if that were not, wherever it is real, the
cessation of a state of mental agony, that the
applause of mankind is reserved. Observations
of a similar nature will easily occur to every
reader respecting the point of honour in the
other sex. The conquest of natural frailties, es¬
pecially in a case of far more importance to
mankind than is at first sight obvious, is well dis¬
tinguished as an object of honour, and the con¬
trary vice is punished by shame. Honour is not
wasted on those who abstain from acts which are
punished by the law. These acts may be avoided
without a pure motive. Wherever a virtue is
easily performed by good men—wherever it is
its nature to be attended by delight—wherever
its outward observance is so necessary to society
as to be enforced by punishment—it is not the
proper object of honour. Honour and shame,
therefore, may be reasonably dispensed, without
being strictly proportioned to the intrinsic mo¬
rality of actions, if the inequality of their distri¬
bution contributes to the general equipoise of
the whole moral system.
A wide disproportion, however, or indeed any
disproportion not justifiable on moral grounds,
would be a depravation of the moral principle.
Duelling is among us a disputed case, though
the improvement of manners has rendered it so
much more infrequent, that it is likely in time
to lose its support from opinion. Those who
excuse individuals for yielding to a false point of
honour, as in the suicides of the Greeks and
Romans, may consistently blame the faulty prin¬
ciple, and rejoice in its destruction. The shame
fixed on a Hindoo widow of rank who volun¬
tarily survives her husband, is regarded by all
other nations with horror.
There is room for great praise and some blame
in other parts of Paley’s works. His political
opinions were those generally adopted by mode¬
rate whigs in his own age. His language on the
Revolution of 1688 may be very advantageously
compared, both in precision and in generous bold¬
ness,1 to that of Blackstone, a great master of
classical and harmonious composition, but a fee¬
ble reasoner and a confused thinker, whose
writings are not exempt from the taint of sla¬
vishness.
It cannot be denied that Paley was sometimes
rather a lax moralist, especially on public duties.
» “ Government may be too secure. The greatest tyrants have been those whose titles were the most, un<l^est^^-
Whenever, therefore, the opinion of right becomes too predominant and superstitious, it is abated by breaking the custom.
Thus the Revolution broke the custom of succession, and thereby moderated, both in the prince and in e pe p ’
lofty notions of hereditary right, which in the one were become a continual incentive to tyranny, and disposed tne ouier to
invite servitude, by undue compliances and dangerous concessions.” (Pai ey, book vi. chap, u.)
392
PRELIMINARY DISSERTATIONS.
It is a sin which easily besets men of strong good
sense, little enthusiasm, and much experience.
They are naturally led to lower their precepts to
the level of their expectations. They see that
higher pretensions often produce less good, to
say nothing of the hypocrisy, extravagance, and
turbulence, to which they lend some colour. As
those who claim more from men often gain less,
it is natural for more sober and milder casuists
to present a more accessible virtue to their fol¬
lowers. It was thus that the Jesuits began, till,
strongly tempted by their perilous station as
the moral guides of the powerful, some of them
by degrees fell into that absolute licentiousness
for which all, not without injustice, have been
cruelly immortalized by Pascal. Indulgence,
which is a great virtue in judgment concerning
the actions of others, is too apt, when blended
in the same system with the precepts of mora¬
lity, to be received as a licence for our own of¬
fences. Accommodation, without which society
would be painful, and arduous affairs would be¬
come impracticable, is more safely imbibed from
temper and experience, than taught in early and
systematic instruction. The middle region be¬
tween laxity and rigour is hard to be fixed, and
it is still harder steadily to remain within its
boundaries. Whatever may be thought of Pa-
ley’s observations on political influence and ec¬
clesiastical subscription, as temperaments and
mitigations which may preserve us from harsh
judgment, they are assuredly not well qualified
to form a part of that discipline which ought to
breathe into the opening souls of youth, at the
critical period of the formation of character,
those inestimable virtues of sincerity, of inte¬
grity, of independence, which will even guide
them more safely through life than mere pru¬
dence, while they provide an inward, fountain of
pure delight, immeasurably more abundant than
all the outward sources of precarious and perish¬
able pleasure.
JEREMY BENTHAM.
The general scheme of this Dissertation would
be a sufficient reason for omitting the name of
a living writer. The devoted attachment and
invincible repugnance which an impartial esti¬
mate of Mr Bentham has to encounter on either
side, are a strong inducement not to deviate
from that scheme in his case. But the most
brief sketch of ethical controversy in England
would be imperfect without it; and perhaps the
utter hopelessness of any expedient for satisfy¬
ing his followers, or softening his opponents,
may enable a writer to look steadily and solely
at what he believes to be the dictates of truth
and justice. He who has spoken of former phi¬
losophers with unreserved freedom, ought per¬
haps to subject his courage and honesty to the
severest test by an attempt to characterize such
a contemporary. Should the very few who are
at once enlightened and unbiassed be of opinion
that his firmness and equity have stood this
trial, they will be the more disposed to trust his
fairness where the exercise of that quality is
more easy.
The disciples of Mr Bentham are more like
the hearers of an Athenian philosopher than the
pupils of a modern professor, or the cool prose¬
lytes of a modern writer. They are in general
men of competent age, of superior understand¬
ing, who voluntarily embrace the laborious study
of useful and noble sciences; who derive their
opinions not so much from the cold perusal of
his writings, as from familiar converse with a
master from whose lips these opinions are re¬
commended by simplicity, disinterestedness, ori¬
ginality, and vivacity; aided rather than im¬
peded by foibles not unamiable, enforced of late
by the growing authority of years and of fame,
and at all times strengthened by that undoubt¬
ing reliance on his own judgment which mightily
increases the ascendant of such a man over those
who approach him. As he and they deserve
the credit of braving vulgar prejudices, so they
must be content to incur the imputation of fall¬
ing into the neighbouring vices of seeking dis¬
tinction by singularity; of clinging to opinions
because they are obnoxious; of wantonly wound¬
ing the most respectable feelings of mankind;
of regarding an immense display of method and
nomenclature as a sure token of a corresponding
increase of knowledge; and of considering them-
DISSERTATION SECOND.
393
selves as a chosen few, whom an initiation into
the most secret mysteries of philosophy entitles
to look down with pity, if not contempt, on the
profane multitude. Viewed with aversion or
dread by the public, they become more bound
to each other and to their master; while they
are provoked into the use of language which
more and more exasperates opposition to them.
A hermit in the greatest of cities, seeing only
his disciples, and indignant that systems of go¬
vernment and law which he believes to be per¬
fect are disregarded at once by the many and
the powerful, Mr Bentham has at length been
betrayed into the most unphilosophical hypothe¬
sis, that all the ruling bodies who guide the
community have conspired to stifle and defeat
his discoveries. He is too little acquainted with
doubts to believe the honest doubts of others,
and he is too angry to make allowance for their
prejudices and habits. He has embraced the
most extreme party in practical politics ; mani¬
festing more dislike and contempt towards those
who are more moderate supporters of popular
principles than towards their most inflexible op¬
ponents. To the unpopularity of his philoso¬
phical and political doctrines he has added the
more general and lasting obloquy which arises
from an unseemly treatment of doctrines and
principles which, if there were no other motives
for reverential deference, even a regard to the
feelings of the best men requires to be approach¬
ed with decorum and respect.
Fifty-three years have passed since the publi¬
cation of Mr Bentham’s first work, A Fragment
on Government,-—a considerable octavo volume,
employed in the examination of a short para¬
graph of Blackstone,—unmatched in acute hy¬
percriticism, but conducted with a severity
which leads to an unjust estimate of the writer
criticised, till the like experiment be repeated on
other writings. It was a waste of extraordinary
power to employ it in pointing out flaws and
patches in the robe occasionally stolen from the
philosophical schools, which hung loosely and
unbecomingly on the elegant commentator. This
volume, and especially the preface, abounds in
fine, original, and just observation; it contains
the germs of most of his subsequent productions,
and it is an early example of that disregard for
the method, proportions, and occasion of a writ¬
ing which, with all common readers, deeply af¬
fects its power of interesting or instructing.
Two years after, he published a most excellent
tract on The Hard Labour Bill, which, concur¬
ring with the spirit excited by Howard’s inqui¬
ries, laid the foundation of just reasoning on Re¬
formatory Punishment. The Letters on Usury'
are perhaps the best specimen of the exhaustive
discussion of a moral or political question, leav¬
ing no objection, however feeble, unanswered,
and no difficulty, however small, unexplained;
remarkable also for the clearness and spirit of
the style, for the full exposition which suits them
to all intelligent readers, for the tender and skilful
hand with which prejudice is touched, and for the
urbanity of his admirable apology for projectors,
addressed to Dr Smith, whose temper and manner
he seems for a time to have imbibed. The Intro¬
duction to the Principles of Morals and Politics,
printed before the Letters, but published after
them, was the first sketch of his system, and is
still the only account of it by himself.
The great merit of this work, and of his other
writings in relation to Jurisprudence properly so
called, is not within our present scope. To the
Roman jurists belongs the praise of having al¬
lotted a separate portion of their Digest to the
signification of the words of most frequent use
1 They were addressed to Mr George Wilson, who retired from the English bar to his native country, and died at Edin¬
burgh in 1816; an early friend of Mr Bentham, and afterwards an intimate friend of Lord Ellenborough, Sir Vicary Gibbs,
and of all the most eminent of his professional contemporaries. The rectitude of judgment purity of heart, elevation of ho¬
nour, the sternness only in integrity, the scorn of baseness, and indulgence towards weakness, which were joined m him
with a gravity exclusive neither of feeling nor of pleasantry, contributed still more than his abilities and attainments of va-
rious sorts, to a moral authority with his friends, and in his profession, which few men more amply possesse , or more use-
fully exercised. The same character, somewhat softened, and the same influence, distinguished his closest rien , ie a e
Mr Lens. Both were inflexible and incorruptible friends of civil and religious liberty, and both knew how 0 ^conc* ,
warmest zeal for that sacred cause, with a charity towards their opponents, which partisans, often more vio en aIJ s - ’
treated as lukewarm. The present writer hopes that the good-natured reader will excuse him for having t ms, P®r
seasonably, bestowed heartfelt commendation on those who were above the pursuit of praise, and the remem iance
good opinion and good-will help to support him under a deep sense of faults and vices.
DISS. II. ** D
394
PRELIMINARY DISSERTATIONS.
in law and legal discussion.1 Bentham not only
first perceived and taught the great value of an
introductory section, composed of definitions of
general terms, as subservient to brevity and pre¬
cision in every part of a code, but he also dis¬
covered the unspeakable importance of natural
arrangement in jurisprudence, by rendering the
mere place of a proposed law in such an arrange¬
ment a short and easy test of the fitness of the
proposal.® But here he does not distinguish be¬
tween the value of arrangement as scaffolding,
and the inferior convenience of its being the very
frame-work of the structure. Mr Bentham, in¬
deed, is much more remarkable for laying down
desirable rules for the determination of rights,
and the punishment of wrongs, in general, than
for weighing the various circumstances which
require them to be modified in different countries
and times in order to render them either more
useful, more easily introduced, more generally
respected, or more certainly executed. The art
of legislation consists in thus applying the prin¬
ciples of jurisprudence to the situation, wants,
interests, feelings, opinions, and habits, of each
distinct community at any given time. It bears
the same relation to jurisprudence which the
mechanical arts bear to pure Mathematics.
Many of these considerations serve to show, that
the sudden establishment of new codes can sel¬
dom be practicable or effectual for their purpose;
and that reformations, though founded on the
principles of jurisprudence, ought to be not
only adapted to the peculiar interests of a people,
but engrafted on their previous usages, and
brought into harmony with those national dis¬
positions on which the execution of laws de¬
pends.® The Romans, under Justinian, adopted
at least the true principle, if they did not apply
it with sufficient freedom and boldness. They
considered the multitude of occasional laws, and
the still greater mass of usages, opinions, and
determinations, as the materials of legislation,
not precluding, but demanding a systematic ar¬
rangement of the whole by the supreme autho¬
rity. Had the arrangement been more scienti¬
fic, had there been a bolder examination and a
more free reform of many particular branches, a
model would have been offered for liberal imi¬
tation by modern lawgivers. It cannot be de¬
nied, without injustice and ingratitude, that Mr
Bentham has done more than any other wri¬
ter to rouse the spirit of juridical reforma¬
tion, which is now gradually examining every
part of law, and, when further progress is fa¬
cilitated by digesting the present laws, will
doubtless proceed to the improvement of all.
Greater praise it is given to few to earn. It
ought to satisfy Mr Bentham, for the disappoint¬
ment of hopes wnich were not reasonable, that
Russia should receive a code from him, or that
North America could be brought to renounce the
variety of her laws and institutions, on the single
authority of a foreign philosopher, whose opinions
had not worked their way either into legislation
or into general reception in his own country.
It ought also to dispose his followers to do fuller
justice to the Romillys and Broughams, with¬
out whose prudence and energy, as well as rea¬
son and eloquence, the best plans of reformation
must have continued a dead letter,—for whose
sake it might have been fit to reconsider the ob¬
loquy heaped on their profession, and to show
more general indulgence to all those whose chief
offence seems to consist in their doubts whether
sudden changes, almost always imposed by vio¬
lence on a community, be the surest road to
lasting improvement.
It is unfortunate that Ethical Theory, with
Digest, lib. 1. tit. 16. De Verborum Significatione.
tW ^Odific1ation’ in the Edinburgh Review, vol. XXIX. p. 217- It need no longer be concealed
° d b7 ^ir Sam,uei R°milly. The steadiness with which he held the balance in weighing the merits of
defects, is an example of his union of the most commanding moral principle with a sensi-
had be£n rele,ased from that stern authority, it would not so long have endured the coarseness and
oughness of human concerns.^ From the tenderness of his feelings, and from an anger never roused but by cruelty and base-
thraffli^ed^wSn^b SfmUS “Z t*8 pure taste’ sPrungthat original and characteristic eloquence, which was the hope of
vea^o TJun b. w ^ "PP1” Ifhis oratory had not flowed so largely from this moral source, which
in polish, ta vigour, ta spleudS^ the 0nly eXample °f “ °m°r "rh°’ “““ ‘he Sge °f S“ty’daily increaSed
“edl^m bfej;We7L1 those wh.0 absolutely require new codes, and those who obstinately adhere to ancient
usages, has been pointed out by M. Meyer, in his most justly celebrated work, Institutions Judiciaires dcs PHncipaux Pays de
l Europe, tome I. Introduction, p. 8, 9. La Haye et Amst. 1819-23, 6 vols. 8vo.
DISSERTATION SECOND.
395
which we are now chiefly concerned, is not the
province in which Mr Bentham has reached the
most desirable distinction. It may be remarked,
both in ancient and in modern times, that what¬
ever modifications prudent followers may intro¬
duce into the system of an innovator, the prin¬
ciples of the Master continue to mould the ha¬
bitual dispositions, and to influence the practical
tendency of the School. Mr Bentham preaches
the principle of utility with the zeal of a disco¬
verer. Occupied more in reflection than in
reading, he knew not, or forgot, how often it
had been the basis, and how generally an essen¬
tial part, of moral systems.1 That in which
he really differs from others, is in the necessity
which he teaches, and the example which he sets,
of constantly bringing that principle before us.
This peculiarity appears to us to be his radical
error. In an attempt, of which the constitution
of human nature forbids the success, he seems
to us to have been led into fundamental errors
in moral theory, and to have given to his practi¬
cal doctrine a dangerous taint.
The confusion of moral approbation with the
moral qualities which are its objects, common to
Mr Bentham with many other philosophers, is
much more uniform and prominent in him than
in most others. This general error, already
mentioned at the opening of this Dissertation,
has led him more than others to assume, that be¬
cause the principle of utility forms a necessary
part of every moral theory, it ought therefore to
be the chief motive of human conduct. Now it
is evident that this assumption, rather tacitly
than avowedly made, is wholly gratuitous. No
practical conclusion can be deduced from the
principle, but that we ought to cultivate those
habitual dispositions which are the most effectual
motives to useful actions. But before a regard
to our own interest, or a desire to promote the wel¬
fare of men in general, be allowed to be the ex¬
clusive, or even the chief regulators of human
conduct, it must be shown that they are the most
effectual motives to such useful actions. It is
demonstrated by experience that they are not.
It is even owned by the most ingenious writers
of Mr Bentham’s school, that desires which are
pointed to general and distant objects, although
they have their proper place and their due value,
are commonly very faint and ineffectual induce¬
ments to action. A theory founded on utility,
therefore, requires that we should cultivate, as
excitements to practice, those other habitual dis¬
positions which we know by experience to be
generally the source of actions beneficial to our¬
selves and our fellows; habits of feeling produc¬
tive of habits of virtuous conduct, and in their
turn strengthened by the re-action of these last.
What is the result of experience on the choice of
the objects of moral culture ? Beyond all dispute,
that we should labour to attain that state of mind
in which all the social affections are felt with the
utmost warmth, giving birth to more compre¬
hensive benevolence, but not supplanted by it;
when the moral sentiments most strongly ap¬
prove what is right and good, without being
perplexed by a calculation of consequences,
though not incapable of being gradually rectifi¬
ed by reason, whenever they are decisively prov¬
ed by experience not to correspond in some of
their parts to the universal and perpetual effects
of conduct. It is a false representation of hu¬
man nature to affirm that “ courage” is only
“ prudence.”2 They coincide in their effects,
and it is always prudent to be courageous. But
a man who fights because he thinks it more haz¬
ardous to yield, is not brave. He does not be¬
come brave till he feels cowardice to be base and
painful, and till he is no longer in need of any
aid from prudence. Even if it were the interest
of every man to be bold, it is clear that so cold
a consideration cannot prevail over the fear of
danger. Where it seems to do so, it must be
by the unseen power either of the fear of shame,
or of some other powerful passion, to which it
lends its name. It was long ago with striking
1 See Notes and Illustrations, note V.
2 Mr Mill’s Analysis of the Human Mind, vol. II. p. 237- It would be unjust not to say that this book, partly perhaps
from a larger adoption of the principles of Hartley, holds out fairer opportunities of negotiation with natural feelings and
the doctrines of former philosophers, than any other production of the same school. But this very assertion about courage
clearly shows at least a forgetfulness that courage, even if it were the offspring of prudence, would not for that reason be a
species of it.
396
PRELIMINARY DISSERTATIONS.
justice observed by Aristotle, that he who ab¬
stains from present gratification, under a dis¬
tinct apprehension of its painful consequences,
is only prudent, and that he must acquire a dis¬
relish for excess on its own account, before he
deserves the name of a temperate man. It is
only when the means are firmly and unalterably
converted into ends, that the process of forming
the mind is completed. Courage may then seek,
instead of avoiding danger. Temperance may
prefer abstemiousness to indulgence. Prudence
itself may choose an orderly government of con¬
duct, according to certain rules, without regard
to the degree in which it promotes welfare.
Benevolence must desire the happiness of others,
to the exclusion of the consideration how far it
is connected with that of the benevolent agent;
and those alone can he accounted just who obey
the dictates of justice from having thoroughly
learned an habitual veneration for its strict rules
and for its larger precepts. In that complete
state the mind possesses no power of dissolving
the combinations of thought and feeling which
impel it to action. Nothing in this argument
turns on the difference between implanted and
acquired principles. As no man can cease, by
any act of his, to see distance, though the power
of seeing it be universally acknowledged to be
an acquisition, so no man has the power to ex¬
tinguish the affections and the moral sentiments,
however much they may he thought to he ac¬
quired, any more than that of eradicating the
bodily appetites. The best writers of Mr Ben-
tham’s school overlook the indissolubility of
these associations, and appear not to bear in
mind that their strength and rapid action con¬
stitute the perfect state of a moral agent.
The pursuit of our own general welfare, or of
that of mankind at large, though from their
vagueness and coldness they are unfit habitual
motives and unsafe ordinary guides of conduct,
yet perform functions of essential importance
in the moral system. The former, which we
call self-love, preserves the balance of all the
active principles which regard ourselves ulti¬
mately, and contributes to subject them to the
authority of the moral principles.1 The latter,
which is general benevolence, regulates in like
manner the equipoise of the narrower affections;
quickens the languid, and checks the encroach¬
ing ; borrows strength from pity, and even from
indignation; receives some compensation, as it
enlarges, in the addition of beauty and grandeur,
for the weakness which arises from dispersion;
enables us to look on all men as brethren, and
overflows on every sentient being. The general
interest of mankind, in truth, almost solely af¬
fects us through the affections of benevolence
and sympathy; for the coincidence of general
with individual interest, even where it is certain,
is too dimly seen to produce any emotion which
can impel to, or restrain from action. As a gen¬
eral truth, its value consists in its completing
the triumph of morality, by demonstrating the
absolute impossibility of forming any theory of
human nature which does not preserve the su¬
periority of virtue over vice; a great, though
not a directly practical advantage.
The followers of Mr Bentham have carried to
an unusual extent the prevalent fault of the more
modern advocates of utility, who have dwelt so
exclusively on the outward advantages of virtue
as to have lost sight of the delight which is a part
of virtuous feeling, and of the beneficial influence
of good actions upon the frame of the mind.
Benevolence towards others,” says Mr Mill,
<£ produces a return of benevolence from them.”2
The fact is true, and ought to he stated. But how
unimportant is it in comparison with that which
is passed over in silence, the pleasure of the affec¬
tion itself, which, if it could become lasting and
intense, would convert the heart into a heaven !
No one who has ever felt kindness, if he could
accurately recall his feelings, could hesitate about
their infinite superiority. The cause of the
general neglect of this consideration is, that it is
only when a gratification is something distinct
from a state of mind, that we can easily learn to
consider it as a pleasure. Hence the great error
respecting the affections, where the inherent de¬
light is not duly estimated, on account of that
very peculiarity of being a part of a state of mind,
1 See Notes and Illustrations, note W.
* Analysis of the Human Mind, vol. II-
DISSERTATION SECOND.
397
which renders it unspeakably more valuable as
independent of every thing without. The social
affections are the only principles of human nature
which have no direct pains. To have any of
these desires is to be in a state of happiness.
The malevolent passions have properly no
pleasures; for that attainment of their purpose
which is improperly so called, consists only in
healing or assuaging the torture which envy,
jealousy, and malice, inflict on the malignant
mind. It might with as much propriety he said
that the toothache and the stone have pleasures,
because their removal is followed by an agree¬
able feeling. These bodily disorders, indeed, are
often cured by the process which removes the
suffering, but the mental distempers of envy
and revenge are nourished by every act of odious
indulgence which for a moment suspends their
pain.
The same observation is applicable to every
virtuous disposition, though not so obviously as
to the benevolent affections. That a brave man
is, on the whole, far less exposed to danger than
a coward, is not the chief advantage of a courage¬
ous temper. Great dangers are rare; hut the
constant absence of such painful and mortifying
sensations as those of fear, and the steady con¬
sciousness of superiority to what subdues ordi¬
nary men, are a perpetual source of inward en¬
joyment. No man who has ever been visited by
a gleam of magnanimity can place any outward
advantage of fortitude in comparison with the
feeling of being always able fearlessly to defend
a righteous cause.1 2 Even Humility, in spite of
first appearances, is a remarkable example. It
has of late been unwarrantably used to signify
that painful consciousness of inferiority which
is the first stage of envy.8 It is a term conse¬
crated in Christian ethics to denote that disposi¬
tion which, by inclining towards a modest esti¬
mate of our qualities, corrects the prevalent
tendency of human nature to overvalue our
merits and to overrate our claims. What can
be a less doubtful or a much more considerable
blessing than this constant sedative, which soothes
and composes the irritable passions of vanity and
pride ? What is more conducive to lasting peace
of mind than the consciousness of proficiency in
that most delicate species of equity which, in the
secret tribunal of conscience, labours to be im¬
partial in the comparison of ourselves with others?
What can so perfectly assure us of the purity of
our moral sense, as the habit of contemplating,
not that excellence which we have reached, but
that which is still to be pursued;3 of not con¬
sidering how far we may outrun others, but how
far we are from the goal ?
Virtue has often outward advantages, and
always inward delights; but the second, though
constant, strong, inaccessible, and inviolable, are
not easily considered by the common observer as
apart from the virtue with which they are blend¬
ed. They are so subtile and evanescent as to
escape the distinct contemplation of all but the
very few who meditate on the acts of mind.
The outward advantages, on the other hand,
cold, uncertain, dependent, and precarious as
they are, yet stand out to the sense and to the
memory, may be handled and counted, and are
perfectly on a level with the general apprehen¬
sion. Hence they have become the almost ex¬
clusive theme of all moralists who profess to fol¬
low reason. There is room for suspecting that
a very general illusion prevails on this subject.
Probably the smallest part of the pleasure of
virtue, because it is the most palpable, has be¬
come the sign and mental representative of the
whole. The outward and visible sign suggests
insensibly the inward and mental delight. Those
who display the external benefits of magnani¬
mity and kindness, would speak with far less
fervour, and perhaps less confidence, if their feel¬
ings were not unconsciously aflected by the
mental state which they overlook in their state¬
ments, though they feel some part of it when
they write or speak on it. When they speak of
1 According to Cicero’s definition of fortitude, “ Virtus pugnans pro aequitate." The remains of the original sense of
Virtus, Manhood, give a beauty and force to these expressions, which cannot be preserved in our language, the Creek
Aoirn, and the German Tugend, originally denoted Strength, afterwards Courage, and at last Virtue. But the happy ( enya-
tion of Virtus from Vir gives an energy to the phrase of Cicero, which illustrates the use of etymology in t e am s o
skilful writer.
2 Mr Mm’s Analysis of the Human Mind, vol. II. p. 222.
* For a description of vanity, by a great orator, see the Rev. R. Hall’s Sermon on Modern Infidelity.
398
PRELIMINARY DISSERTATIONS.
what is without, they feel what was within, and
their words excite the same feeling in others.
Is it not probable that much of our love of
praise may be thus ascribed to humane and
sociable pleasure in the sympathy of others with
us ? Praise is the symbol which represents sym¬
pathy, and which the mind insensibly substitutes
for it in recollection and in language. Does not
the desire of posthumous fame, in like manner,
manifest an ambition for the fellow-feeling of our
race, when it is perfectly unproductive of any
advantage to ourselves ? In this point of view,
it may be considered as the passion of which the
very existence proves the mighty power of dis¬
interested desire. Every other pleasure from
sympathy is confined to the men who are now
alive. The love of fame alone seeks the sym¬
pathy of unborn generations, and stretches the
chain which hinds the race of man together, to
an extent to which hope sets no bounds. There
is a noble, even if unconscious, union of morality
with genius in the mind of him who sympathizes
with the masters who lived twenty centuries
before him, in order that he may learn to com¬
mand the sympathies of the countless genera¬
tions who are to come.
In the most familiar, as well as in the highest
instances, it would seem, that the inmost thoughts
and sentiments of men are more pure than their
language. Those who speak of “ a regard to
character,” if they he serious, generally infuse
into that word, unawares, a large portion of that
sense in which it denotes the frame of the mind.
Those who speak of “ honour” very often mean
a more refined and delicate sort of conscience,
which ought to render the more educated classes
of society alive to such smaller wrongs as the la¬
borious and the ignorant can scarcely feel. What
heart does not warm at the noble exclamation of
the ancient poet: <c Who is pleased by false
honour, or frightened by lying infamy, but he
who is false and depraved!” Every uncorrupted
mind feels unmerited praise as a bitter reproach,
and regards a consciousness of demerit as a drop
ot poison in the cup of honour. How different
is the applause which truly delights us all, a
proof that the consciences of others are in har¬
mony with our own ! “ What,” says Cicero,
“ is glory hut the concurring praise of the good,
the unhought approbation of those who judge
aright of excellent virtue !” A far greater than
Cicero rises from the purest praise of man, to
more sublime contemplations.
Fame is no plant that grows on mortal soil,
But lives and spreads aloft, by those pure eyes
And perfect witness of all-judging Jove.
Those who have most inculcated the doctrine
of utility have given another notable example of
the very vulgar prejudice which treats the un¬
seen as insignificant. Tucker is the only one of
them who occasionally considers that most im¬
portant effect of human conduct which consists
in its action on the frame of the mind, by fitting
its faculties and sensibilities for their appointed
purpose. A razor or a penknife would well
enough cut cloth or meat; hut if they were often
so used, they would he entirely spoiled. The
same sort of observation is much more strongly
applicable to habitual dispositions, which, if they
he spoiled, we have no certain means of repla¬
cing or mending. Whatever act, therefore, dis¬
composes the moral machinery of mind, is more
injurious to the welfare of the agent than most
disasters from without can he; for the latter are
commonly limited and temporary; the evil of
the former spreads through the whole of life.
Health of mind, as well as of body, is not only
productive in itself of a greater sum of enjoy¬
ment than arises from other sources, hut is the
only condition of our frame in which we are ca¬
pable of receiving pleasure from without. Hence
it appears how incredibly absurd it is to prefer,
on grounds of calculation, a present interest to
the preservation of those mental habits on wrhich
our wellbeing depends. When they are most
moral, they may often prevent us from obtaining
advantages. It would he as absurd to desire to
lower them for that reason, as it would be to
weaken the body, lest its strength should render
it more liable to contagious disorders of rare
occurrence.
It is, on the other hand, impossible to com¬
bine the benefit of the general habit with the
advantages of occasional deviation; for every
such deviation either produces remorse, or weak¬
ens the habit, and prepares the way for its gra¬
dual destruction. He who obtains a fortune by
the undetected forgery of a will, may indeed he
DISSERTATION SECOND.
399
honest in his other acts; but if he had such a
scorn of fraud before as he must himself allow
to be generally useful, he must suffer a severe
punishment from contrition; and he will be
haunted with the fears of one who has lost his
own security for his good conduct. In all cases,
if they be well examined, bis loss by the distem¬
per of his mental frame will outweigh the profits
of his vice.
By repeating the like observation on similar
occasions, it will be manifest that the infirmity
of recollection, aggravated by the defects of lan¬
guage, gives an appearance of more selfishness
to man than truly belongs to his nature; and
that the effect of active agents upon the habitual
state of mind, one of the considerations to which
the epithet t£ sentimental” has of late been ap¬
plied in derision, is really among the most se¬
rious and reasonable objects of moral philosophy.
When the internal pleasures and pains which
accompany good and bad feelings, or rather form
a part of them, and the internal advantages and
disadvantages which follow good and bad actions,
are sufficiently considered, the comparative im¬
portance of outward consequences will be more
and more narrowed; so that the Stoical philoso¬
pher may be thought almost excusable for re¬
jecting it altogether, were it not an indispensably
necessary consideration for those in whom right
habits of feeling are not sufficiently strong.
They alone are happy, or even truly virtuous,
who have little need of it.
The later moralists who adopt the principle
of utility, have so misplaced it, that in their
hands it has as great a tendency as any theore¬
tical error can have, to lessen the intrinsic plea¬
sure of virtue, and to unfit our habitual feelings
for being the most effectual inducements to good
conduct. This is the natural tendency of a dis¬
cipline which brings utility too closely and fre¬
quently into contact with action. By this ha¬
bit, in its best state, an essentially weaker mo¬
tive is gradually substituted for others which
must always be of more force. The frequent
appeal to utility as the standard of action tends
to introduce an uncertainty with respect to the
conduct of other men, which would render all
intercourse insupportable. It affords also so
fair a disguise for selfish and malignant passions,
as often to hide their nature from him who is
their prey. Some taint of these mean and evil
principles will at least creep in, and by their
venom give an animation not its own to the cold
desire of utility. The moralists who take an
active part in those affairs which often call out
unamiable passions, ought to guard with peculiar
watchfulness against such self-delusions. The
sin that must most easily beset them, is that of
sliding from general to particular consequences,
—that of trying single actions, instead of dis¬
positions, habits, and rules, by the standard of
utility,—that of authorizing too great a latitude
for discretion and policy in moral conduct,—
that of readily allowing exceptions to the most
important rules,—that of too lenient a censure
of the use of doubtful means when the end seems
to them good,—and that of believing unphiloso-
phically, as well as dangerously, that there can
be any measure or scheme so useful to the world
as the existence of men who would not do a base
thing for any public advantage. It was said of
Andrew Fletcher, “ he would lose his life to
serve his country, but would not do a base thing
to save it.” Let those preachers of utility who
suppose that such a man sacrifices ends to means,
consider whether the scorn of baseness be not
akin to the contempt of danger, and whether a
nation composed of such men would not be in¬
vincible. But theoretical principles are coun¬
teracted by a thousand causes, which confine
their mischief as well as circumscribe their be¬
nefits. Men are never so good or so bad as
their opinions. All that can be with reason ap¬
prehended is, that they may always produce
some part of their natural evil, and that the
mischief will be greatest among the many who
seek excuses for these passions. Aristippus
found in the Socratic representation of the union
of virtue and happiness a pretext for sensuality;
and many Epicureans became voluptuaries in
spite of the example of their master; easily drop¬
ping by degrees the limitations by which he
guarded his doctrines. In proportion as a man
accustoms himself to be influenced by the utility
of particular acts, without regard to rules, he
approaches to the casuistry of the Jesuits, and
to the practical maxims of Coesar Borgia.
Injury on this as on other occasions has been
400
PRELIMINARY DISSERTATIONS.
suffered by Ethics, from its close affinity to Ju¬
risprudence. The true and eminent merit of Mr
Bentham is that of a reformer of jurisprudence.
He is only a moralist with a view to being a
jurist; and he sometimes becomes for a few
hurried moments a metaphysician with a view to
laying the foundation of both the moral sciences.
Both he and his followers have treated Ethics
too juridically. They do not seem to be aware,
or at least they do not bear constantly in mind,
that there is an essential difference in the sub¬
jects of these two sciences.
The object of law is the prevention of actions
injurious to the community. It considers the
dispositions from which they flow only indirect¬
ly, to ascertain the likelihood of their recur¬
rence, and thus to determine the necessity and
the means of preventing them. The direct ob¬
ject of Ethics is only mental disposition. It
considers actions indirectly as the signs by which
such dispositions are manifested. If it were
possible for the mere moralist to see that a moral
and amiable temper was the mental source of a
bad action, he could not cease to approve and
love the temper, as we sometimes presume to
suppose may be true of the judgments of the
Searcher of Hearts. Religion necessarily coin¬
cides with morality in this respect; and it is the
peculiar distinction of Christianity that it places
the seat of virtue in the heart. Law and Ethics
are necessarily so much blended, that in many
intricate combinations the distinction becomes
obscure. But in all strong cases the difference is
evident. Thus, law punishes the most sincerely
repentant; but wherever the soul of the penitent
can be thought to be thoroughly purified, reli¬
gion and morality receive him with open arms.
It is needless, after these remarks, to observe,
that those whose habitual contemplation is di¬
rected to the rules of action, are likely to under¬
rate the importance of feeling and disposition;
an error of very unfortunate consequences, since
the far greater part of human actions flow from
these neglected sources; while the law inter¬
poses only in cases which may be called excep¬
tions, which are now rare, and ought to be less
frequent.
The coincidence of Mr Bentham’s school with
the ancient Epicureans in the disregard of the
pleasures of taste and of the arts dependent on
imagination, is a proof both of the inevitable
adherence of much of the popular sense of the
words “ interest” and “ pleasure,” to the same
words in their philosophical acceptation, and of
the pernicious influence of narrowing (i utility”
to mere visible and tangible objects, to the ex¬
clusion of those which form the larger part of
human enjoyment.
The mechanical philosophers who, under Des¬
cartes and Gassendi, began to reform Physics in
the seventeenth century, attempted to explain
all the appearances of nature by an immediate
reference to the figure of particles of matter im¬
pelling each other in various directions, and with
unequal force, but in all other points alike. The
communication of motion by impulse they con¬
ceived to be perfectly simple and intelligible. It
never occurred to them, that the movement of
one ball when another is driven against it, is
a fact of which no explanation can be given
which will amount to more than a statement of
its constant occurrence. That no body can act
where it is not, appeared to them as self-evident
as that the whole is equal to all the parts. By
this axiom they understood that no body moves
another without touching it. They did not per¬
ceive, that it was only self-evident where it
means that no body can act where it has not the
power of acting ; and that if it be understood
more largely, it is a mere assumption of the pro¬
position on which their whole system rested.
Sir Isaac Newton reformed Physics, not by
simplifying that science, but by rendering it
much more complicated. He introduced into it
the force of attraction, of which he ascertained
many laws, but which even he did not dare to
represent as being as intelligible and as con¬
ceivably ultimate as impulsion itself. It was
necessary for Laplace to introduce intermediate
laws, and to calculate disturbing forces, before
the phenomena of the heavenly bodies could be
reconciled even to Newton’s more complex theory.
In the present state of physical and chemical
knowledge, a man who should attempt to refer
all the immense variety of facts to the simple
impulse of the Cartesians, would have no chance
of serious confutation. The number of laws
augments with the progress of knowledge. The
DISSERTATION SECOND.
401
■
speculations of the followers of Mr Bentham are
not unlike the unsuccessful attempt of the Car¬
tesians. Mr Mill, for example, derives the whole
theory of Government1 from the single fact, that
every man pursues his interest when he knows
it; which he assumes to he a sort of self-evident
practical principle, if such a phrase be not con¬
tradictory. That a man’s pursuing the interest
of another, or indeed any other object in nature,
is just as conceivable as that he should pursue his
own interest, is a proposition which seems never
to have occurred to this acute and ingenious
writer. Nothing, however, can he more certain
than its truth, if the term “ interest” he em¬
ployed in its proper sense of general wellbeing,
which is the only acceptation in which it can
serve the purpose of his arguments. If, indeed,
the term be employed to denote the gratification
of a predominant desire, his proposition is self-
evident, but wholly unserviceable in his argu¬
ment; for it is clear that individuals and multi¬
tudes often desire what they know to be most
inconsistent with their general welfare. A na¬
tion, as much as an individual, and sometimes
more, may not only mistake its interest, hut, per¬
ceiving it clearly, may prefer the gratification of
a strong passion to it.2 3 The whole fabric of his
political reasoning seems to be overthrown by
this single observation; and instead of attempt¬
ing to explain the immense variety of political
facts by the simple principle of a contest of in¬
terests, we are reduced to the necessity of once
more referring them to that variety of passions?
habits, opinions, and prejudices, which we dis¬
cover only by experience. Mr Mill’s Essay on
Education* atfords another example of the incon¬
venience of leaping at once from the most gene¬
ral laws, to a multiplicity of minute appearances.
Having assumed, or at least inferred from insuf¬
ficient premises, that the intellectual and moral
character is entirely formed by circumstances, he
proceeds, in the latter part of the essay, as if it
were a necessary consequence of that doctrine
that we might easily acquire the power of com¬
bining and directing circumstances in such a
manner as to produce the best possible character.
Without disputing for the present the theoreti¬
cal proposition, let us consider what would be
the reasonableness of similar expectations in a
more easily intelligible case. The general theory
of the winds is pretty well understood; we
know that they proceed from the rushing of air
from those portions of the atmosphere which are
more condensed, into those which are more rare¬
fied ; hut how great a chasm is there between
that simple law and the great variety of facts
which experience teaches us respecting winds!
The constant winds between the tropics are
large and regular enough to be in some measure
capable of explanation; but who can tell why,
in variable climates, the wind blows to-day from
the east, to-morrow from the west ? Who can
foretell what its shiftings and variations are to
he ? Who can account for a tempest on one
day, and a calm on another ? Even if we could
foretell the irregular and infinite variations, how
far might we not still be from the power of com¬
bining and guiding their causes ? No man but
the lunatic in the story of Rasselas ever dreamt
that he could command the weather. The diffi¬
culty plainly consists in the multiplicity and
minuteness of the circumstances which act on
the atmosphere. Are those which influence the
formation of the human character likely to be
less minute and multiplied ?
The style of Mr Bentham underwent a more
remarkable revolution than perhaps he-fell that
of any other celebrated writer. In his early
works, it was clear, free, spirited, often and sea¬
sonably eloquent. Many passages of his later
writings retain the inimitable stamp of genius;
but he seems to have been oppressed by the vast¬
ness of his projected works,—to have thought
that he had no longer more than leisure to pre¬
serve the heads of them,—to have been impelled
by a fruitful mind to new plans before he had
completed the old. In this state of things, he
1 Essay on Government, originally printed m the Supplement to the fourth, fifth, and sixth editions of the Encyclopaxlia
Britannica.
2 The same mode of reasoning has been adopted by the writer of a late criticism on Mr Minn’s Essay. See Edinburgh
Review, No. 97, March 1829.
3 In the Supplement to the Encyclopaedia Britannica.
DISS. II. 3 E
402
PRELIMINARY DISSERTATIONS.
gradually ceased to use words for conveying his
thoughts to others, hut merely employed them
as a short-hand to preserve his meaning for his
own purpose. It was no wonder that his lan¬
guage should thus become obscure and repulsive.
Though many of his technical terms are in them¬
selves exact and pithy, yet the overflow of his
vast nomenclature was enough to darken his
whole diction.
It was at this critical period that the arrange¬
ment and translation of his manuscripts were
undertaken by M. Dumont, a generous disciple,
who devoted a genius formed for original and
lasting works, to diffuse the principles and pro¬
mote the fame of his master. He whose pen
Miraheau did not disdain to borrow,—who, in
the same school with Romilly, had studiously
pursued the grace as well as the force of com¬
position,—was perfectly qualified to strip of its
DUGALD
Manifold are the discouragements rising up
at every step in that part of this Dissertation
which extends to very recent times. No sooner
does the writer escape from the angry disputes
of the living, than he may feel his mind clouded
by the name of a departed friend. But there
are happily men whose fame is brightened by
free discussion, and to whose memory an ap¬
pearance of belief that they needed tender treat¬
ment would be a grosser injury than it could
suffer from a respectable antagonist.
Dugatd Stewart was the son of Dr Matthew
Stewart, Professor of Mathematics in the Uni¬
versity of Edinburgh; a station immediately
before filled by Maclaurin, on the recommenda¬
tion of Newton. Hence the poet spoke of “ the
philosophic sire and son.”8 He was educated
at Edinburgh, and he heard the lectures of Reid
at Glasgow. He was early associated with his
father in the duties of the Mathematical Profes¬
sorship ; and during the absence of Dr Adam
Ferguson as Secretary to the Commissioners
sent to conclude a peace with North America,
he occupied the chair of Moral Philosophy. He
uncouthness a philosophy which he understood
and admired. As he wrote in a general lan¬
guage, he propagated its doctrines throughout
Europe, where they were beneficial to jurispru¬
dence, hut perhaps injurious to the cause of re¬
formation in government. That they became
more popular abroad than at home, is partly to
be ascribed to the taste and skill of M. Dumont;
partly to that tendency towards free specula¬
tion and bold reform which was more prevalent
among nations newly freed, or impatiently aspir¬
ing to freedom, than in a people long satisfied
with the possession of a system of government
like that which others were struggling to ob¬
tain, and not yet aware of the imperfections
and abuses in their laws, to the amendment of
which a cautious consideration of Mr Bentham’s
works will undoubtedly most materially con¬
tribute.
STEWART.1
was appointed to the Professorship on the resig¬
nation of Ferguson, not the least distinguished
among the modern moralists inclined to the
Stoical school.
This office, filled in immediate succession by
Ferguson, Stewart, and Brown, received a
lustre from their names, which it owed in no
degree to its modest exterior or its limited ad¬
vantages ; and was rendered by them the highest
dignity, in the humble, but not obscure, esta¬
blishments of Scottish literature. The lectures of
Mr Stewart, for a quarter of a century, render¬
ed it famous through every country where the
light of reason was allowed to penetrate. Per¬
haps few men ever lived, who poured into the
breasts of youth a more fervid and yet reason¬
able love of liberty, of truth, and of virtue.
How many are still alive, in different countries,
and in every rank to which education reaches,
who, if they accurately examined their own
minds and lives, would not ascribe much of
whatever goodness and happiness they possess,
to the early impressions of his gentle and per¬
suasive eloquence ! He lived to see his disciples
1 Born in 1753; died in 1828.
s Burns.
DISSERTATION SECOND.
403
distinguished among the lights and ornaments
of the council and the senate.1 He had the
consolation to he sure that no words of his pro¬
moted the growth of an impure taste, of an ex¬
clusive prejudice, of a malevolent passion. With¬
out derogation from his writings, it may be said
that his disciples were among his best works.
He, indeed, who may justly he said to have cul¬
tivated an extent of mind which would other¬
wise have lain barren, and to have contributed
to raise virtuous dispositions where the natural
growth might have been useless or noxious, is
not less a benefactor of mankind, and may indi¬
rectly he a larger contributor to knowledge, than
the author of great works, or even the discoverer
of important truths. The system of conveying
scientific instruction to a large audience by
lectures, from which the English universities
have in a great measure departed, renders his
qualities as a lecturer a most important part oi
his merit in a Scottish university which still ad¬
heres to the general method of European educa¬
tion. Probably no modern ever exceeded him
in that species of eloquence which springs from
sensibility to literary beauty and moral excel¬
lence ; which neither obscures science by pro¬
digal ornament, nor disturbs the serenity of pa¬
tient attention ; hut though it rather calms and
soothes the feelings, yet exalts the genius, and
insensibly inspires a reasonable enthusiasm for
whatever is good and fair.
He embraced the philosophy of Dr Reid, a
patient, modest, and deep thinker,2 who, in his
first work {Enquiry into the Human Mind), de¬
serves a commendation more descriptive of a
philosopher than that bestowed by Professor
Cousin—of having made “ a vigorous protest
against scepticism on behalf of common sense.
His observations on suggestion, on natural signs,
on the connection between what he calls sensa¬
tion and perception, though perhaps occasioned
by Berkeley, whose idealism Reid had once
adopted, are marked by the genuine spirit of
original observation. As there are too many
who seem more wise than they are, so it was the
more uncommon fault of Reid to appear less
a philosopher than he really was. Indeed his
temporary adoption of Berkeleianism is a proof
of an unprejudiced and acute mind. Perhaps no
man ever rose finally above the seductions of
that simple and ingenious system, who had not
sometimes tried their full effect by surrendering
his whole mind to them.
But it is never with entire impunity that
philosophers borrow vague and inappropriate
terms from vulgar use. Never did man afford
a stronger instance of the danger than Reid, in
his two most unfortunate terms, Common Sense
and Instinct. Common Sense is that average
portion of understanding, possessed by most men,
which, as it is nearly always applied to conduct,
has acquired an almost exclusively practical
1 As an example of Mr Stewart’s school may be mentioned Francis Horner, a favourite pupil, and, till his last moment,
an affectionate friend. The short life of this excellent person is worthy of serious contemplation, by those more especia y,
wUt“— like his, enter on the slippery path oVU^^du^SeU^Sa^^
sembly where aristocratical propensities prevail,—by his understanding n 1 _ •> P ’ f unbending integrity, and
more bv modest independence, by steadiness and sincerity, joined to moderatmn —by the stamp of ^b^d g 7
by the conscientious considerateness which breathed through his well-chosen a g g ’ r of reasoning could'have
of thirty-six, to a moral authority which, without these qualities no brilha"f. Lr Hi?s h”lh place was
acquired. No eminent speaker in Parliament owed so touchi„| unanimity
therefore honourable to his audience and to his country. Regre , . from theatrical display, and whose
from every part of a divided assembly, unused to manifatatrons of ^ thosel„
tribute on such an occasion derived its peculiar value e bv whom he w;Lf- praised, wept, and honoured,-
whom he was unknown were shed over him; and at the head of r ^ f ATr Tjornpr v,v his discernment and veracity,
was one, whose commendation would have been more enhanced in ic e , . , afforded bv the name of Howard.
t*lan-Tn ^ siplal Pr C-On*,Ur^^^u^descriotiml wiU^o welftcMveigh'the'wordsof the'mos’ cmn^tent of judges,
2 Those who may doubt the justice of this descnption will cl ^ - certainly verv rare that a piece so deeply philo-
who, though candid and even indulgent, was not prodigal of pra _ rpn(ipr Whenever l enter into your ideas,
sophical is wrote with so much spirit, and affords so much enter ^nmc-r^ ^ ^ correct and so good English, that I found
no man appears to express himself with greater perspicuity. frje^idlv adversaries Dr Campbell and Dr Gerard, and
publication) sufficiently shows, that Mr Hume felt no displeasure iq? amiable man an elegant and tender poet,
midable antagonists, however he might resent the language o . ’ Truth an unfair appeal to the multitude
and a good writer cm miscellaneous literature in prose, but who, in his ^ namnhfeteen
on philosophical questions-indulged himself in the personalities and invectives of a popular pamphleteer.
404
PRELIMINARY DISSERTATIONS.
sense. Instinct is the habitual power of pro¬
ducing effects like contrivances ot reason, yet
so far beyond the intelligence and experience of
the agent, as to be utterly inexplicable by refer¬
ence to them. No man, if he had been in search
of improper words, could have discovered any
more unfit than these two, for denoting that
law, or state, or faculty of mind, which compels
us to acknowledge certain simple and very ab¬
stract truths, not being identical propositions,
to lie at the foundation of all reasoning, and to
be the necessary ground of all belief.
Long after the death of Dr Reid, his philoso¬
phy was taught at Paris by M. Royer Collard,1
who, on the restoration of free debate, became
the most philosophical orator of his nation, and
now fills, with impartiality and dignity, the
chair of the Chamber of Deputies. His inge¬
nious and eloquent scholar, Professor Cousin,
dissatisfied with what he calls <c the sage and
timid” doctrines of Edinburgh, which he con¬
sidered as only a vigorous protest, on behalf of
common sense, against the scepticism of Hume,
sought in Germany for a philosophy of “ such
a masculine and brilliant character as might
command the attention of Europe, and be able
to struggle with success on a great theatre,
against the genius of the adverse school.”* It
may be questioned whether he found in Kant
more than the same vigorous protest, under a
more systematic form, with an immense nomen¬
clature, and constituting a philosophical edifice
of equal symmetry and vastness. The prefer¬
ence of the more boastful system, over a philo¬
sophy thus chiefly blamed for its modest preten¬
sions, does not seem to be entirely justified by
its permanent authority in the country which
gave it birth; where, however powerful its in¬
fluence still continues to be, its doctrines do not
appear to have now many supporters : and, in¬
deed, the accomplished Professor himself rapid¬
ly shot through Kantianism, and now appears
to rest or to stop at the doctrines of Schelling
and Hegel, at a point so high, that it is hard to
descry from it any distinction between objects,
—even that indispensable distinction between
Reality and Illusion. As the works of Reid,
and those of Kant, otherwise so different, ap¬
pear to be simultaneous efforts of the conserva¬
tive power of philosophy to expel the mortal
poison of scepticism, so the exertions of M.
Royer Collard and M. Cousin, however at va¬
riance in metaphysical principles, seem to have
been chiefly roused by the desire of delivering
Ethics from that fatal taint of personal, and,
indeed, gross interest, which that science had
received in France from the followers of Con¬
dillac, especially Helvetius, St Lambert, and
Cabanis. The success of these attempts to ren¬
der Speculative Philosophy once more popular
in the country of Descartes, has already been
considerable. The French youth, whose desire
of knowledge and love of liberty afford an aus¬
picious promise of the succeeding age, have
eagerly received doctrines, of which the moral
part is so much more agreeable to their liberal
spirit, than the selfish theory, generated in the
stagnation of a corrupt, cruel, and dissolute
tyranny.
These agreeable prospects bring us easily back
to our subject; for though the restoration of
Speculative Philosophy in the country of Des¬
cartes is due to the precise statement and vi¬
gorous logic of M. Royer Collard, the modifica¬
tions introduced by him into the doctrine of
Reid coincide with those of Mr Stewart, and
would have appeared to agree more exactly, if
the forms of the French philosopher had not been
more dialectical, and the composition of Mr
Stewart had retained less of that oratorical cha¬
racter, which belonged to a justly celebrated
speaker. Amidst excellencies of the highest
order, his writings, it must be confessed, leave
some room for criticism. He took precautions
against offence to the feelings of his contempo¬
raries, more anxious and frequent than the im¬
patient searcher for truth may deem necessary.
For the sake of promoting the favourable re-
* Fragments of his lectures have been recently published in a French translation of Dr Reid, by M. Jonffroy: CEuvres
■Completes de Thomas Reid, vol. IV. Paris, 1828.
* Court de Philosophic, par M. Cousin, letjon xii. Paris, 1828.
DISSERTATION SECOND.
405
ception of philosophy itself, he studies perhaps
too visibly to avoid whatever might raise up
prejudices against it. His gratitude and native
modesty dictated a superabundant care in sof¬
tening and excusing his dissent from those who
had been his own instructors, or who were the
objects of general reverence. Exposed by his
station, both to the assaults of political preju¬
dice, and to the religious animosities of a coun¬
try where a few sceptics attacked the slumber¬
ing zeal of a Calvinistic people, it would have
been wonderful if he had not betrayed more
wariness than would have been necessary or be¬
coming in a very different position. The ful¬
ness of his literature seduced him too much into
multiplied illustrations. Too many of the ex¬
pedients happily used to allure the young may
unnecessarily swell his volumes. Perhaps a
successive publication in separate parts made
him more voluminous than he would have been
if the whole had been at once before his eyes.
A peculiar susceptibility and delicacy of taste
produced forms of expression, in themselves ex¬
tremely beautiful, hut of which the habitual use
is not easily reconcilable with the condensation
desirable in works necessarily so extensive. If,
however, it must be owned that the caution in¬
cident to his temper, his feelings, his philosophy,
and his station, has somewhat lengthened his
composition, it is not less true, that some of the
same circumstances have contributed towards
those peculiar beauties which place him at the
head of the most adorned writers on philosophy
in our language.
Few writers rise with more grace from a
plain groundwork, to the passages which require
greater animation or embellishment. He gives
to narrative, according to the precept of Bacon,
the colour of the time, by a selection of happy
expressions from original writers. Among the
secret arts by which he diffuses elegance over
his diction, may be remarked the skill which,
by deepening or brightening a shade in a se¬
condary term, by opening partial or prepara¬
tory glimpses of a thought to he afterwards un¬
folded, unobservedly heightens the import of a
word, and gives it a new meaning, without any
offence against old use. It is in this manner
that philosophical originality may he reconciled
to purity and stability of speech,—that we may
avoid new terms, which are the easy resource of
the unskilful or the indolent, and often a cha¬
racteristic mark of writers who love their lan¬
guage too little to feel its peculiar excellencies,
or to study the art of calling forth its powers.
He reminds us not unfrequently of the cha¬
racter given by Cicero to one of his contempo¬
raries, “ who expressed refined and abstruse
thought in soft and transparent diction.” His
writings are a proof that the mild sentiments
have their eloquence as well as the vehement
passions. It would be difficult to name works
in which so much refined philosophy is joined
with so fine a fancy,—so much elegant litera¬
ture, with such a delicate perception of the
distinguishing excellencies of great writers, and
with an estimate in general so just of the ser¬
vices rendered to knowledge by a succession of
philosophers. They are pervaded by a philoso¬
phical benevolence, which keeps up the ardour
of his genius, without disturbing the serenity of
his mind,—which is felt in his reverence for
knowledge, in the generosity of his praise, and
in the tenderness of his censure. It is still more
sensible in the general tone with which he re¬
lates the successful progress of the human un¬
derstanding, among many formidable enemies.
Those readers are not to he envied who limit
their admiration to particular parts, or to excel¬
lencies merely literary, without being warmed
by the glow of that honest triumph in the ad¬
vancement of knowledge, and of that assured
faith in the final prevalence of truth and justice,
which breathe through every page of them, and
give the unity and dignity of a moral purpose
to the whole of these classical works.
He has often quoted poetical passages, of which
some throw much light on our mental opera¬
tions. If he sometimes prized the moral com¬
mon-places of Thomson and the speculative
fancy of Akenside more highly than the higher
poetry of their betters, it was not to be wonder¬
ed at that the metaphysician and the moralist
should sometimes prevail over the lover of poetry.
His natural sensibility was perhaps occasionally
cramped by the cold criticism of an unpoetical
age; and some of his remarks may be thought
to indicate a more constant and exclusive regard
406
PRELIMINARY DISSERTATIONS.
to diction than is agreeable to the men of a ge¬
neration who have been trained by tremendous
events to a passion for daring inventions, and to
an irregular enthusiasm, impatient of minute
elegancies and refinement. Many of those beau¬
ties which his generous criticism delighted to
magnify in the works of his contemporaries,
have already faded under the scorching rays of
a fiercer sun.
Mr Stewart employed more skill in contriving,
and more care in concealing, his very important
reforms of Reid’s doctrines, than others exert to
maintain their claims to originality. Had his
well-chosen language of “ laws of human thought
or belief” been at first adopted in that school,
instead of “ instinct” and “ common sense,” it
would have escaped much of the reproach (which
Dr Reid himself did not merit) of shallowness
and popularity. Expressions so exact, employed
in the opening, could not have failed to influence
the whole system, and to have given it, not only
in the general estimation, hut in the minds of its
framers, a more scientific complexion. In those
parts of Mr Stewart’s speculations in which he
most departed from his general principles, he
seems sometimes, as it were, to he suddenly
driven back by what he unconsciously shrinks
from as ungrateful apostasy; and to he desirous
of making amends to his master, by more harsh¬
ness, than is otherwise natural to him, towards
the writers whom he has insensibly approached.
Hence perhaps the unwonted severity of his lan¬
guage towards Tucker and Hartley. It is thus
at the very time when he largely adopts the
Principle of Association in his excellent Essay
on the Beautiful,1 that he treats most rigidly
the latter of these writers, to whom, though nei¬
ther the discoverer nor the sole advocate of that
principle, it surely owes the greatest illustration
and support.
In matters of far other importance, causes
perhaps somewhat similar may have led to the
like mistake. When he absolutely contra¬
dicts Dr Reid, by truly stating that “ it is
more philosophical to resolve the power of
habit into the association of ideas, than to re¬
solve the association of ideas into habit,”2 * he,
in the sequel of the same volume,5 refuses to go
farther than to own, that “ the theory of Hart¬
ley concerning the origin of our affections, and
of the moral sense, is a most ingenious refinement
on the selfish system, and that by means of it the
force of many of the common reasonings against
that system is eluded;” though he somewhat
inconsistently allows, that <c active principles
which, arising from circumstances in which all
the situations of mankind must agree, are there¬
fore common to the whole species, at whatever
period of life they may appear, are to be regard¬
ed as a part of human nature, no less than the
instinct of suction; in the same manner as the
acquired perception of distance, by the eye, is
to be ranked among the perceptive powers of
man, no less than the original perceptions of the
other senses.”4 In another place also he makes
a remark on mere beauty, which might have led
him to a more just conclusion respecting the the¬
ory of the origin of the affections and the moral
sense: “ It is scarcely necessary forme to observe,
that, in those instances where association operates
in heightening (or he might have said creates) the
pleasures we receive from sight, the pleasing emo¬
tion continues still to appear, to our conscious¬
ness, simple and uncompounded.”* To this re¬
mark he might have added, that until all the
separate pleasures he melted into one,—as long
as any of them are discerned and felt as distinct
from each other,—the associations are incom¬
plete, and the qualities which gratify are not
called by the name of beauty. In like manner,
as has been repeatedly observed, it is only when
all the separate feelings, pleasurable and pain¬
ful, excited by the contemplation of voluntary
action, are lost in the general sentiments of ap-
1 Stewart’s Philosophical Essays, part ii. essay i. especially chap. vi. The condensation, if not omission, of the discussion
of the theories of Huffier, Reynolds, Burke, and Price, in this essay, would have lessened that temporary appearance which
is unsuitable to a scientific work.
1 Elements of the Philosophy of the Human Mind, vol. I. p. 281, edit. 1792, 4to.
’ Ibid. p. 383.
♦ Ibid. p. 385.
* Philosophical Essays, part ii. essay i. chap. vi.
DISSERTATION SECOND.
407
probation or disapprobation,—when these gene¬
ral feelings retain no trace of the various emo¬
tions which originally attended different actions,
—when they are held in a state of perfect fusion
by the habitual use of the words used in every
language to denote them,—that conscience can
be said to exist, or that we can be considered
as endowed with a moral nature. The theory
which thus ascribes the uniform formation of
the moral faculty to universal and paramount
laws, is not a refinement of the selfish system,
nor is it any modification of that hypothesis.
The partisans of selfishness maintain, that in
acts of will the agent must have a view to the
pleasure or happiness which he hopes to reap
from it. The philosophers who regard the social
affections and the moral sentiments as formed by
a process of association, on the other hand, con¬
tend that these affections and sentiments must
work themselves clear from every particle of
self-regard, before they deserve the names of
benevolence and of conscience. In the actual
state of human motives, the two systems are not
to be likened, but to be contrasted to each other.
It is remarkable that Mr Stewart, who admits
the “ question respecting the origin of the affec¬
tions to be rather curious than important,”1
should have held a directly contrary opinion
respecting the moral sense;2 * * to which these
words, in his sense of them, seem to be equally
applicable. His meaning in the former affirma¬
tion is, that if the affections be acquired, yet they
are justly called natural; and if their origin be
personal, yet tbeir nature may and does become
disinterested. What circumstance distinguishes
the former from the latter case ? With respect
to the origin of the affections, it must not be
overlooked that his language is somewhat con¬
tradictory. For if the theory on that subject
from which he dissents were merely “ a refine¬
ment on the selfish system,” its truth or false¬
hood could not be represented as subordinate,
since the controversy would continue to relate
to the existence of disinterested motives of hu¬
man conduct.5 It may also be observed, that
he uniformly represents his opponents as de¬
riving the affections from self-love, which, in its
proper sense, is not the source to which they
refer even avarice; and which is itself derived
from other antecedent principles, some of which
are inherent, and some acquired. If the object
of this theory of the rise of the most important
feelings of human nature were, as our philoso¬
pher supposes, “ to elude objections against the
selfish system,” it would be at best worthless. Its
positive merits are several. It affirms the actual
disinterestedness of human motives, as strongly
as Butler himself. The explanation of the men¬
tal law, of Avhich benevolence and conscience
are formed habitually, when it is contemplated
deeply, impresses on the mind the truth that
they not only are but must be disinterested. It
confirms, as it were, the testimony of conscious¬
ness, by exhibiting to the understanding the
means employed to insure the production of dis¬
interestedness. It affords the only effectual an¬
swer to the prejudice against the disinterested
theory, from the multiplication of ultimate facts
and implanted principles, which, under all its
other forms, it seems to require. No room is
left for this prejudice by a representation of dis¬
interestedness, which ultimately traces its forma¬
tion to principles almost as simple as those of
Hobbes himself. Lastly, every step in just ge¬
neralization is an advance in philosophy. No
one has yet shown, either that man is not ac¬
tually disinterested, or that he may not have
been destined to become so by such a process
as has been described:—the cause to which the
eftects are ascribed is a real agent, which seems
adequate to the appearance; and if future obser¬
vation should be found to require that the theory
shall be confined within narrower limits, such a
limitation will not destroy its value.
The acquiescence of Mr Stewart in Dr Reid’s
general representation of our mental constitu-
1 Outlines of Moral Philosophy, p. 93. M
* Outlines, 'p. 117. “ This is the most important question that can he stated with respect to the Theory of Morals.
5 In the Philosophy of the Active and Moral Powers of Man (vol. I. p. 164) Mr Stewart has done more manifest injustice
to the Hartleian theory, by calling it “ a doctrine fundamentally the. same" with the selfish system, and especially by represent¬
ing Hartley, who ought to be rather classed with Butler and Hume, as agreeing with Gay, Tucker, and 1’aley.
408
PRELIMINARY DISSERTATIONS.
tion, led him to indulge more freely the natural
bent of his understanding, by applying it to theo¬
ries of character and manners, of life and litera¬
ture, of taste and the arts, more than to the con¬
sideration of those more simple principles which
rule over human nature under every form. His
chief work, as he frankly owns, is indeed rather
a collection of such theories, pointing toward the
common end of throwing light on the structure
and functions of the mind, than a systematic
treatise, such as might be expected from the title
of “ Elements.” It is in essays of this kind
that he has most surpassed other cultivators of
mental philosophy. His remarks on the effects
of casual associations may be quoted as a speci¬
men of the most original and just thoughts, con¬
veyed in the best manner.1 In this beautiful
passage, he proceeds from their power of con¬
fusing speculation, to that of disturbing expe¬
rience and of misleading practice; and ends with
their extraordinary effect in bestowing on trivial,
and even ludicrous circumstances, some portion
of the dignity and sanctity of those sublime prin¬
ciples with which they are associated. The
style, at first only clear, afterwards admitting
the ornaments of a calm and grave elegance, at
last rising to as high a strain as philosophy will
endure, and of which all the parts (various as
their nature is) are held together by an invisible
thread of gentle transition, affords a specimen
of adaptation of manner to matter which it will
be hard to match in any philosophical writer.
Another very fine remark, which seems to be as
original as it is just, may be quoted as a sample
of those beauties with which his writings abound.
“ The apparent coldness and selfishness of man¬
kind may be traced, in a great measure, to a
want of attention and a want of imagination. In
the case of those misfortunes which happen to
ourselves or our near connections, neither of
these powers is necessary to make us acquainted
with our situation. But without an uncommon
degree of both, it is impossible for any man
to comprehend completely the situation of his
neighbour, or to have an idea of the greater part
of the distress which exists in the world. If
we feel more for ourselves than for others,
in the former case the facts are more fully be¬
fore us than they can be in the latter.”8 Yet
several parts of his writings afford the most
satisfactory proof, that his abstinence from w hat
is commonly called metaphysical speculation,
arose from no inability to pursue it with sig¬
nal success. As examples, his observations on
General Terms, and on Causation, may be ap¬
pealed to with perfect confidence. In the first
two Dissertations of the volume bearing the title
of Philosophical Essays, he with equal boldness
and acuteness grapples with the most extensive
and abstruse questions of mental philosophy, and
points out both the sources and the uttermost
boundaries of human knowledge with a Verula-
mean hand. In another part of his writings, he
calls what are denominated first principles of
experience, “fundamental laws of human belief,
or primary elements of human reason;”5 which
last form of expression has so close a resemblance
to the language of Kant, that it should have pro¬
tected the latter from the imputation of writing
jargon.
Mr Stewart’s excellent volume entitled Out¬
lines of Moral Philosophy,4 though composed only
as a text-book for the use of his hearers, is one
of the most decisive proofs that he was perfectly
qualified to unite precision with ease, to be brief
with the utmost clearness, and to write with be¬
coming elegance in a style where the meaning
is not overladen by ornaments. This volume
contains his properly Ethical Theory,5 which is
much expanded, but not substantially altered, in
his Philosophy of the Active and Moral Powers,5—
a work almost posthumous, and composed under
circumstances which give it a deeper interest than
can be inspired by any desert in science. Though,
with his usual modesty, he manifests an anxiety
to fasten his ethical theory to the kindred specu¬
lations of other philosophers of the Intellectual
School, especially to those of Cudworth, recent¬
ly clothed in more modern phraseology by Price,
yet he still shows that independence and origin-
* Elements of the Philosophy of the Human Mind, vol. I. p. 340-352.
* Ibid- vol. I. p. 502.
* Ibid. vol. II. p. 57-
4 Edinburgh, 1794, 8vo.
s P. 76-148.
5 Two vols. 8vo. Edinburgh, 1828.
DISSERTATION SECOND.
409
ality which all his aversion from parade could
not entirely conceal. Right, duty, virtue, moved
obligation, and the like or the opposite forms of
expression, represent, according to him, certain
thoughts, which arise necessarily and instantane¬
ously in the mind (or in the reason, if we take
that word in the large sense in which it denotes
all that is not emotive) at the contemplation of
actions, and which are utterly incapable of all
resolution, consequently of all explanation, and
which can be known only by being experienced.
These thoughts or ideas, or by whatever other
name they may be called, are followed as inex¬
plicably, but as inevitably, by pleasurable and
painful emotions, which suggest the conception
of moral beauty ; a quality of human actions dis¬
tinct from their adherence to or deviation from rec¬
titude, though generally coinciding with it. The
question which a reflecting reader will here put
is, whether any purpose is served by the intro¬
duction of the intermediate mental process be¬
tween the particular thoughts and the moral
emotions. How would the view be darkened or
confused, or indeed in any degree changed, by
withdrawing that process, or erasing the words
which attempt to express it? No advocate of
the intellectual origin of the moral faculty has yet
stated a case in which a mere operation of reason
or judgment, unattended by emotion, could, con¬
sistently with the universal opinion of mankind,
as it is exhibited by the structure of language,
be said to have the nature or to produce the
effects of Conscience. Such an example would
be equivalent to an experimentum crucis on the
side of that celebrated theory. The failure to
produce it, after long challenge, is at least
a presumption against it, nearly approach¬
ing to that sort of decisively discriminative
experiment. It would be vain to restate what
has already been too often repeated, that all
the objections to the selfish philosophy turn upon
the actual nature, not upon the original source
of our principles of action; and that it is by a
confusion of these very distinct questions alone
that the confutation of Hobbes can be made ap¬
parently to involve Hartley. Mr Stewart ap¬
pears, like most other metaphysicians, to have
blended the inquiry into the nature of our moral
sentiments with that other which only seeks a
mss. ii.
criterion to distinguish moral from immoral
habits of feeling and action; for he considers
the appearance of moral sentiment at an early
age, before the general tendency of actions could
be ascertained, as a decisive objection to the
origin of these sentiments in association,—an
objection which assumes that, if utility be the
criterion of morality, associations with utility
must be the mode by which the moral sentiments
are formed, which no skilful advocate of the
theory of association will ever allow. That the
main, if not sole object of conscience is to go¬
vern our voluntary exertions, is manifest. But
how could it perform this great function if it
did not impel the will ? and how could it have
the latter effect as a mere act of reason, or in¬
deed in any respect otherwise than as it is made
up of emotions, by which alone its grand aim
could in any degree be attained ? Judgment and
reason are therefore preparatory to conscience,
not properly a part of it. That the exclusion of
reason reduces virtue to be a relative quality,
is another instance of the confusion of the two
questions in moral theory; for though a fitness
to excite approbation may be only a relation of
objects to our susceptibility, yet the proposition
that all virtuous actions are beneficial, is a pro¬
position as absolute as any other within the
range of our understanding.
A delicate state of health, and an ardent de¬
sire to devote himself exclusively to study and
composition, induced Mr Stewart, while in the
full blaze of his reputation as a lecturer, to re¬
tire, in 1810, from the labour of public instruc¬
tion. This retirement, as he himself describes
it, was that of a quiet but active life. Three
quarto and two octavo volumes, besides the
magnificent Dissertations prefixed to this En¬
cyclopaedia, were among its happy fruits. These
Dissertations are, perhaps, the most profusely
ornamented of any of his compositions ; a pecu¬
liarity which must in part have arisen from a
principle of taste, which regarded decoration as
more suitable to the history of philosophy than
to philosophy itself. But the memorable in¬
stances of Cicero, of Milton, and still more those
of Dryden and Burke, seem to show that there
is some natural tendency in the fire of genius to
burn more brightly or to blaze more fiercely in
3 F
410
PRELIMINARY DISSERTATIONS.
the evening than in the morning of human life.
Probably the materials which long experience
supplies to the imagination, the boldness with
which a more established reputation arms the
mind, and the silence of the low but formidable
rivals of the higher principles, may concur in pro¬
ducing this unexpected and little observed effect.
It was in the last years of his life, when suf¬
fering under the effects of a severe attack of
palsy, with which he had been afflicted in 1822,
that Mr Stewart most plentifully reaped the
fruits of long virtue and a well-ordered mind.
THOMAS
A writer, as he advances in life, ought to
speak with diffidence of systems which he had
only begun to consider with care after the age in
which it becomes hard for his thoughts to flow
into new channels. A reader cannot be said
practically to understand a theory, till he has
acquired the power of thinking, at least for a
short time, with the theorist. Even a hearer,
with all the helps of voice in the instructor, of
countenance from him and from fellow-hearers,
finds it difficult to perform this necessary process
without either being betrayed into hasty and un¬
distinguishing assent, or falling, while he is in
pursuit of an impartial estimate of opinions, in¬
to an indifference about their truth. I have felt
this difficulty in reconsidering ancient opinions:
but it is perhaps more needful to own its power,
and to warn the reader against its effects, in the
case of a philosopher well known to me, and
with whom common friendships stood in the
stead of much personal intercourse, as a cement
of kindness.
I very early read Brown’s Observations on
Happily for him, his own cultivation and exer¬
cise of every kindly affection had laid up for
him a store of that domestic consolation which
none who deserve it ever want, and for the
loss of which, nothing beyond the threshold can
make amends. The same philosophy which he
had cultivated from his youth upward employed
his dying hand. Aspirations after higher and
brighter scenes of excellence, always blended
with his elevated morality, became more earnest
and deeper as worldly passions died away, and
earthly objects vanished from his sight.
BROWN.1
the Zoonomia of Dr Darwin, the perhaps un¬
matched work of a boy in the eighteenth year
of his age.2 His first tract on Causation ap¬
peared to me the finest model of discussion in
mental philosophy since Berkeley and Hume;
with this superiority over the latter, that its aim
is that of a philosopher who seeks to enlarge
knowledge, not that of a sceptic, the most illus¬
trious of whom have no better end than that of
displaying their powers in confounding and dark¬
ening every truth; so that their very happiest
efforts cannot be more leniently described than
as brilliant fits of mental debauchery.3 From a
diligent perusal of his succeeding works at the
time of their publication, I was prevented by
pursuits and duties of a very different nature.
These causes, together with ill health and grow¬
ing occupation, hindered me from reading his
Lectures with due attention, till it has now be¬
come a duty to consider with care that part of
them which relates to Ethics.
Dr Brown was born in one of those families
of ministers in the Scottish church who, after a
1 Born in 1778 ; died in 1820.
2 Welsk’8 Life of Brown, p. 43 ; a pleasingly affectionate work, full of analytical spirit and metaphysical reading,—of
such merit, in short, that I could wish to have found in it no phrenology. Objections a priori in a case dependent on facts
are indeed inadmissible. Even the allowance of presumptions of that nature would open so wide a door for prejudices, that
at most they can be considered only as maxims of logical prudence, which fortify the watchfulness of the individual. The
tatal objection to phrenology seems to me to be, that what is new in it, or peculiar to it, has no approach to an adequate
tounnation in experience. rx- ^
“ a Writ,erwh°’ Pervading human nature at his ease, struck into the province of paradox as an exercise for the
unwearied vigour ot his mind ; who, with a soul superior to the sharpest attacks of fortune, and a heart practised to the
P~r os°phy, had not enough of real greatness to overcome that last foible of superior minds, the temptation of honour
w'hich the academic exercise ot wit is conceived to bring to its professor.” So Warburton (Divine Legation, booki. sect. 4),
speaking ot Bayle, but perhaps m part excusing himself—in a noble strain, of which it would have been more agreeable to
tind the repetition than the contrast in his language towards Hume.
DISSERTATION SECOND.
411
generation or two of a humble life spent in
piety and usefulness, with no more than needful
knowledge, have more than once sent forth a
man of genius from their cool and quiet shade,
to make his fellows wiser or better by tongue or
pen, by head or hand. Even the scanty endow¬
ments and constant residence of that church, by
keeping her ministers far from the objects which
awaken turbulent passions and disperse the un¬
derstanding on many pursuits, afforded some of
the leisure and calm of monastic life, without
the exclusion of the charities of family and kin¬
dred. It may be well doubted whether this un¬
dissipated retirement, which during the eigh¬
teenth century was very general in Scotland, did
not make full amends for the loss of curious and
ornamental knowledge, by its tendency to quali¬
fy men for professional duty, by the cultivation
of reason among a considerable number, and by
those opportunities for high meditation, and for
the unchangeable concentration of mind on wor¬
thy objects, to the few who had the natural capa¬
city for such exertions.1
An authentic account of the early exercises of
Brown’s mind is preserved by his biographer.2
At the age of nineteen he took a part with others,
some of whom became the most memorable men
of their time, in the foundation of a private so¬
ciety in Edinburgh, under the name of “ the
Academy of Physics.”3
The character of Dr Brown is very attractive,
as an example of one in whom the utmost ten¬
derness of affection, and the indulgence of a
flowery fancy, were not repressed by the high¬
est cultivation, and by a perhaps excessive re¬
finement of intellect. His mind soared and
roamed through every region of philosophy and
poetry; but his untravelled heart clung to the
hearth of his father, to the children who shared it
with him, and after them, first to the other part¬
ners of his childish sports, and then almost solely
to those companions of his youthful studies who
continued to be the friends of his life. Specula¬
tion seemed to keep his kindness at home. It is
observable, that though sparkling with fancy, he
does not seem to have been deeply or durably
touched by those affections which are lighted at
its torch, or at least tinged with its colours. His
heart sought little abroad, but contentedly dwelt
in his family and in his study. He was one of
those men of genius who repaid the tender care
of a mother by rocking the cradle of her repos¬
ing age. He ended a life spent in searching foi
truth, and exercising love, by desiring that he
should be buried in his native parish, with his
<£ dear father and mother.” Some of these
delightful qualities were perhaps hidden from
the casual observer in general society, by the
want of that perfect simplicity of manner which
is doubtless their natural representative. Man¬
ner is a better mark of the state of a mind, than
those large and deliberate actions which form
what is called conduct. It is the constant and
insensible transpiration of character. In serious
acts a man may display himself. In the thou¬
sand nameless acts which compose manner, the
mind betrays its habitual bent. But manner is
then only an index of disposition, when it is that
of men who live at ease in the intimate famili¬
arity of friends and equals. It may be diverted
from simplicity by causes which do not reach so
deep as the character; by bad models, or by a
restless and wearisome anxiety to shine, arising
from many circumstances, none of which are pro¬
bably more common than the unseasonable ex¬
ertions of a recluse student in society, and the
1 See Sib H. Moncreiff’s Life of the Reverend Dr Ershine.
* Welsh’s Life of Brown, p. 77. and App. p. 498.
3 A part of the first day’s minutes is here borrowed from Mr Welsh:—“ 7th January 1797—Present, Mr Erskine, Pre¬
sident,—Mr Brougham, Mr Reddie, Mr Brown, Mr Birbeck, Mr Leyden,” &c. who were afterwards joined by Lord Webb
Seymour, Messrs Horner, Jeffrey, Smyth, &c. Mr Erskine, who thus appears at the head of so remarkable an association,
and whom diffidence and untoward circumstances have hitherto withheld from the full manifestation of his powers, conti¬
nued to be the bosom friend of Brown to the last, and showed the constancy of his friendship for others by converting all his
invaluable preparations for a translation of Sultan Baber’s Commentaries (perhaps the best, certainly the most European
work of modern eastern prose) into the means of completing the imperfect attempt of Leyden ; with a regard equally ge¬
nerous to the fame of his early friend, and to the comfort of that friend’s surviving relations. The review of Baber’s Com~
mentaries, by M. Silvestre de Sacy, in the Journal des Savans for May and June 1829, is perhaps one of the best specimens ex¬
tant of the value of literary commendation when it is bestowed with conscientious calmness, and without a suspicion of bias,
by one of the greatest orientalists, in a case where he pronounces every thing to have been done by Mr Erskine “ which
could have been performed by the most learned and the most scrupulously conscientious of editors and translators.”
412
preliminary dissertations.
unfortunate attempts of some others, to take by
violence the admiration of those with whom
they do not associate with ease. The association
with unlike or superior companions which least
distorts manners, is that which takes place with
those classes whose secure dignity generally
renders their own manners easy; with whom
the art of pleasing or of not displeasing each
other in society is a serious concern; who have
leisure enough to discover the positive and ne¬
gative parts of the smaller moralities; and who,
being trained to a watchful eye on what is ludi¬
crous, apply the lash of ridicule to alfectation,
the most ridiculous of faults. The busy in
every department of life are too respectably oc¬
cupied to form these manners or to bestow them.
They are the frivolous work of polished idleness ;
and perhaps their most serious value consists in
the war which they wage against affectation;
though even there they betray their nature in
punishing it, not as a deviation from nature, but
as a badge of vulgarity.
The prose of Dr Brown is brilliant to excess.
‘ It must not be denied that its beauty is some¬
times womanly; that it too often melts down
precision into elegance ; that it buries the main
idea under a load of illustration, of which every
part is expanded and adorned with such a visi¬
ble labour, as to withdraw the mind from atten¬
tion to the thoughts which it professes to intro¬
duce more easily into the understanding. It is
darkened by excessive brightness ; it loses ease
and liveliness by over-dress; and, in the midst
of its luscious sweetness, we wish for the strik¬
ing and homely illustrations of Tucker, and for
the pithy and sinewy sense of Paley, either of
whom, by a single short metaphor from a fami¬
liar, perhaps a low object, could at one blow set
the two worlds of reason and fancy in move¬
ment.
It would he unjust to censure severely the de¬
clamatory parts of his Lectures; they are excus¬
able in the first warmth of composition. They
might even be justifiable allurements in attracting
young hearers to abstruse speculations. Had he
lived, he would probably have taken his thoughts
out of the declamatory forms of spoken address,
and given to them the appearance, as well as
the reality, of deep and subtile discussion. The
habits indeed of so successful a lecturer, and the
natural luxuriancy of his mind, could not fail to
have somewhat tinctured all his compositions;
hut though he might still have fallen short of
simplicity, he certainly would have avoided
much of the diffusion, and even common-place,
which hang heavily on original and brilliant
thoughts; for it must be owned, that though, as
a thinker, he is unusually original, yet when he
falls among the declaimers, he is infected by
their common-places.
In like manner, he would assuredly have
shortened or left out many of the poetical quo¬
tations which he loved to recite, and which
hearers even beyond youth hear with delight.
There are two very different sorts of passages of
poetry to be found in works on philosophy,
which are as far asunder from each other in
value as in matter. A philosopher will admit
some of those wonderful lines or words which
bring to light the infinite varieties of character,
the furious bursts or wily workings of passion,
the winding approaches of temptation, the slip¬
pery path to depravity, the beauty of tender¬
ness, the grandeur of what is awful and holy in
man. In every such quotation, the moral phi¬
losopher, if he be successful, uses the best mate¬
rials of his science; for what are they hut the
results of experiment and observation on the hu¬
man heart, performed by artists of far other skill
and power than his ? They are facts which could
have only been ascertained by Homer, by Dante,
by Shakspeare, by Cervantes, by Milton. Every
year of admiration since the unknown period
when the Iliad first gave delight, has extorted
new proofs of the justness of the picture of hu¬
man nature, from the responding hearts of the
admirers. Every strong feeling which these
masters have excited is a successful repetition
of their original experiment, and a continually
growing evidence of the greatness of their dis¬
coveries. Quotations of this nature may he the
most satisfactory, as well as the most delightful,
proofs of philosophical positions. Others of in¬
ferior merit are not to be interdicted : a pointed
maxim, especially when familiar, pleases, and is
recollected. I cannot entirely conquer my pas¬
sion for the Roman and Stoical declamation ol
some passages in Lucan and Akenside. But
DISSERTATION SECOND.
413
quotations from those who have written on phi¬
losophy in verse, or, in other words, from those
who generally are inferior philosophers, and vo¬
luntarily deliver their doctrines in the most dis¬
advantageous form, seem to be unreasonable. It
is agreeable, no doubt, to the philosopher, still
more to the youthful student, to meet his abstruse
ideas clothed in the sonorous verse of Akenside.
The surprise of the unexpected union of verse
with science is a very lawful enjoyment. But
such slight and momentary pleasures, though
they may tempt the writer to display them, do not
excuse a vain effort to obtrude them on the sym¬
pathy of the searcher after truth in after-times.
It is peculiarly unlucky that Dr Brown should
have sought supposed ornament from the moral
common-places of Thomson, rather than from
that illustration of philosophy which is really to
he found in his picturesque strokes.
Much more need not he said of Dr Brown’s
own poetry, somewhat voluminous as it is, than
that it indicates fancy and feeling, and rose
at least to the rank of an elegant accomplish¬
ment. It may seem a paradox, hut it appears
to me that he is really most poetical in those
poems and passages which have the most pro¬
perly metaphysical character. For every various
form of life and nature, when it is habitually
contemplated, may inspire feeling; and the just
representation of these feelings may he poe¬
tical. Dr Brown observed man, and his wider
world, with the eye of a metaphysician; and
the dark results of such contemplations, when
he reviewed them, often filled his soul with
feelings which, being both grand and melan¬
choly, were truly poetical. Unfortunately, how¬
ever, few readers can he touched with fellow-
feeling. He sings to few, and must be content
with sometimes moving a string in the soul of
the lonely visionary, who, in the day-dreams of
youth, has felt as well as meditated on the mys¬
teries of nature. His heart has produced charm¬
ing passages in all his poems; hut, generally
speaking, they are only beautiful works of art
and imitation. The choice of Akenside as a fa¬
vourite and a model may, without derogation
from that writer, he considered as no proof of a
poetically formed mind.1 There is more poetry
in many single lines of Cowper than in volumes
of sonorous verses such as Akenside’s. Philoso¬
phical poetry is very different from versified
philosophy. The former is the highest exertion
of genius, the latter cannot he ranked above the
slighter amusements of ingenuity. Dr Brown’s
poetry was, it must he owned, composed either
of imitations, which, with some exceptions, may
he produced and read without feeling, or of effu
sions of such feelings only as meet a rare and
faint echo in the human breast.
A few words only can here be bestowed on the
intellectual part of his philosophy. It is an open
revolt against the authority of Reid; and, by a
curious concurrence, he began to lecture nearly
at the moment when the doctrines of that phi¬
losopher came to be taught with applause in
France. Mr Stewart had dissented from the
language of Reid, and had widely departed from
his opinions on several secondary theories. Dr
Brown rejected them entirely. He very justly
considered the claim of Reid to the merit of de¬
tecting the universal delusion which had be¬
trayed philosophers into the belief that ideas
which were the sole objects of knowledge had a
separate existence, as a proof of his having mis¬
taken their illustrative language for a metaphy¬
sical opinion ;2 hut he does not do justice to the
service which Reid really rendered to mental
science, by keeping the attention of all future
speculators in a state of more constant watchful¬
ness against the transient influence of such an
illusion. His choice of the term feeling* to de¬
note the operations which we usually refer to
the understanding, is evidently too wide a do
parture from its ordinary use, to have any pro¬
bability of general adoption. No definition can
strip so familiar a word of the thoughts and
emotions which have so long accompanied it, so
as to fit it for a technical term of the highest
i His accomplished friend Mr Erskine confesses that Brown’s poems ‘are not written in the language plain and gro^
emotion. The string touched is too delicate for general sympathy. They are in an unknown tongue to one halt (tie
might have said nineteen twentieths) “ of the reading part of the community.” (Welsh s L*fe°fBr™n’ P’ ^
* Brown’s Lectures, vol. II. p. 1-49. 3 voL .L P- 220’ &C’
414
PRELIMINARY DISSERTATIONS.
abstraction. If we can be said to have a feeling
<£ of the equality of the angle of forty-five degrees
to half the angle of ninety degrees,”1 we may call
Geometry and Arithmetic sciences of feeling. He
has very forcibly stated the necessity of assum¬
ing “ the primary universal intuitions of direct be¬
lief” which, in their nature, are incapable of all
proof. They seem to be accurately described as
notions which cannot be conceived separately,
but without which nothing can be conceived.
They are not only necessary to reasoning and to
belief, but to thought itself. It is equally im¬
possible to prove or to disprove them. He has
very justly blamed the school of Reid for “ an
extravagant and ridiculous” multiplication of
those principles which he truly represents as
inconsistent with sound philosophy. To philo¬
sophize is indeed nothing more than to simplify
securely.2
The substitution of suggestion for the former
phrase, association of ideas, would hardly deserve
notice in so cursory a view, if it had not led him
to a serious misconception of the doctrines and
deserts of other philosophers. The fault of the
latter phrase is rather in the narrowness of the
last, than in the inadequacy of the first word.
Association presents the fact in the light of a re¬
lation between two mental acts. Suggestion de¬
notes rather the power of the one to call up the
other. But whether we say that the sight of
ashes suggests fire, or that the ideas of fire and
ashes are associated, we mean to convey the
same fact; and, in both cases, an exact thinker
means to accompany the fact with no hypothe¬
sis. Dr Brown has supposed the word associa¬
tion as intended to affirm that there was some
“ intermediate process”3 between the original
succession of the mental acts, and the power
which they acquired therefrom of calling up
each other. This is quite as much to raise up
imaginary antagonists for the honour of con¬
quering them, as he justly reprehends Dr Reid
for doing in the treatment of preceding philoso¬
phers. He falls into another more important
and unaccountable error, in representing his own
reduction of Mr Hume’s principles of association
(resemblance, contrariety, causation, contiguity
in time or place) to the one principle of conti¬
guity, as a discovery of his own, by which his
theory is distinguished from “ the universal
opinion of philosophers.”4 Nothing but too ex¬
clusive a consideration of the doctrines of the
Scottish school could have led him to speak thus
of what was hinted by Aristotle, distinctly laid
down by Hobbes, and fully unfolded both by
Hartley and Condillac. He has, however, ex¬
tremely enlarged the proof and the illustration
of this law of mind, by the exercise of cc a more
subtile analysis,” and the disclosure of “ a finer
species of proximity.”5 As he has thus aided
and confirmed, though he did not discover the
general law, so he has rendered a new and very
important service to mental science, by what he
properly calls “ secondary laws of suggestion”6
or association,—circumstances which modify the
action of the general law, and must be distinct¬
ly considered, in order to explain its connection
with the phenomena. The enumeration and
exposition are instructive, and the example is
worthy of commendation. For it is in this lower
region of science that most remains to be dis¬
covered ; it is that which rests most on observa¬
tion, and least tempts to controversy; it is by
improvements in that part of knowledge that the
foundations are secured, and the whole building
so repaired as to rest steadily on them. The
distinction of common language between the
head and the heart, which, as we have seen, is
so often overlooked or misapplied by metaphy¬
sicians, is, in the system of Brown, signified by
the terms {C mental states” and 4C emotions.” It
is unlucky that no single word could be found
for the former, and that the use of “ feeling,”
as the generic term, should disturb its easy
1 Brown’s Lectures, vol. I. p. 222.
* Dr Brown always expresses himself best where he is short and familiar. “ An hypothesis is nothing more than a rea¬
son for making one experiment or observation rather than another.” {Lectures, vol. I. p. 170.) In 1812, as the present
writer observed to him that Reid and Hume differed more in words than in opinion, he answered, “ Yes. Reid bawled out,
we must believe an outward world ; but added in a whisper, we can give no reason for our belief. Hume cries out, we can
give no reason for such a notion; and whispers, I own we cannot get rid of itd’
* Lectures, vol. II. p. 335-347- 4 Ibid. vol. II. p. 349. 5 Ibid. vol. II. p. 218, &c. * ' Ibid. vol. II. p. 270.
DISSERTATION SECOND.
415
comprehension when it is applied more natu¬
rally.
In our more proper province he has followed
Butler, who appears to have been chiefly known
to him through Mr Stewart, in the theory of the
social affections. Their disinterestedness is en¬
forced by the arguments of both these philoso¬
phers, as well as of Hutcheson.1 It is observ¬
able, however, that he applies the principle of
suggestion or association boldly to this part of
human nature, and seems inclined to refer to it
even sympathy itself.2 It is hard to understand
how, with such a disposition on the subject of a
principle so generally thought ultimate as Sym¬
pathy, he should, inconsistently with himself, fol¬
low Mr Stewart in representing the theory which
derives the affections from association as “ a
Modification of the Selfish System.”3 He mistakes
that theory by stating, that it derives the affec¬
tions from our experience that our own interest
was connected with that of others; while in
truth it considers our regard to our own interest
as formed from the same original pleasures by
association, which, by the like process, may and
do directly generate affections towards others,
without passing through the channel of regard
to our general happiness. But, says he, this is
only an hypothesis, since the formation of thfese
affections is acknowledged to belong to a time
of which there is no remembrance;4—an objec¬
tion fatal to every theory of any mental function,
—s ub versive, for exampl e, of Berkel ey’s discovery
of acquired visual perception, and most strange¬
ly inconsistent in the mouth of a philosopher
whose numerous simplifications of mental theory
are and must be founded on occurrences which
precede experience. It is in all other cases, and
it must be in this, sufficient that the principle of
the theory is really existing, that it explains the
appearances, that its supposed action resembles
what we know to be its action in those similar
cases of which we have direct experience. Last¬
ly, he in express words admits that, according
to the theory to which he objects, wTe have af¬
fections which are at present disinterested.5 Is
it not a direct contradiction in terms to call
such a theory “ a modification of the selfish
system?” His language in the sequel clearly
indicates a distrust of his own statement, and a
suspicion that he is not only inconsistent, but
altogether mistaken.6
As we enter more deeply into the territory of
Ethics, we at length discover in Brown a distinc¬
tion, the neglect of which by preceding specula¬
tors we have more than once lamented as pro¬
ductive of obscurity and confusion :—“ The
moral affections,” says he, “ which I consider at
present, I consider rather physiologically” (or,
as he elsewhere better expresses it, C{ psycholo¬
gically”) “ than ethically, as parts of our mental
constitution, not as involving the f ulfilment or vio¬
lation of duties.”1 He immediately, however,
loses sight of this distinction, and reasons incon¬
sistently with it, instead of following it to its
proper consequences in his explanation of con¬
science. Perhaps, indeed, (for the words are
capable of more than one sense,) he meant to
distinguish the virtuous affections from those
sentiments which have morality exclusively in
view, rather than to distinguish the theory of
moral sentiment from the attempt to ascertain
the characteristic quality of right action. Friend¬
ship is conformable in its dictates to morality;
but it may, and does exist, without any view to
it. He who feels the affections, and performs
the duties of friendship, is the object of that
distinct emotion which is called moral appro¬
bation.
It is on the subject of conscience that, in imi¬
tation of Mr Stewart, and with no other argu¬
ments than his, he makes his chief stand against
the theory which considers the formation of that
master faculty itself as probably referable to tbe
necessary and universal operation of those laws
of human nature to which he himself ascribes
almost every other state of mind. On both sides
of this question the supremacy of conscience is
alike held to be venerable and absolute. Once
' Brown’s Lectures, vol. III. p. 248.
2 Ibid. vol. III. p. 282.
3 Ibid. vol. IV. p. 82, et seq.
* Ibid. vol. IV. p. 87*
1 Ibid. vol. IV. p. 87-
6 Ibid. vol. IV. p. 94-97*
7 Ibid. vol. III. p. 231.
416
PRELIMINARY DISSERTATIONS.
more, be it remembered, that the question is
purely philosophical, and is only whether, from
the impossibility of explaining its formation by
more general laws, we are reduced to the neces¬
sity of considering it as an original fact in hu¬
man nature, of which no further account can he
given. Let it, however, be also remembered,
that we are not driven to this supposition by
the mere circumstance, that no satisfactory ex¬
planation has yet appeared; for there are many
analogies in an unexplained state of mind to
states already explained, which may justify us
in believing that the explanation requires only
more accurate observation, and more patient
meditation, to he brought to that completeness
which it probably will attain.
SECTION VII.
GENERAL REMARKS.
Having thus again premised an already often
repeated warning, it remains that we should
offer a few observations on the questions so
understood, which naturally occur on the con¬
sideration of Dr Brown’s argument in sup¬
port of the proposition, that moral approbation
is not only in its mature state independent of
and superior to any other principle of human
nature, regarding which there is no dispute, but
that its origin is altogether inexplicable, and
that its existence is an ultimate fact in mental
science. Though these observations are imme¬
diately occasioned by the perusal of Brown, they
are yet, in the main, of a general nature, and
might have been made without reference to any
particular writer.
The term Suggestion, which might be inof¬
fensive in describing merely intellectual asso¬
ciations, becomes peculiarly unsuitable when it
is applied to those combinations of thought with
emotion, and to those unions of feeling, which
compose the emotive nature of man. Its com¬
mon sense of a sign recalling the thing signified,
always embroils the new sense vainly forced
upon it. No one can help owning, that if it
were consistently pursued, so as that we were to
speak of suggesting a feeling or passion, the lan¬
guage would be universally thought absurd. To
suggest love or hatred is a mode of expression so
manifestly incongruous, that most readers would
choose to understand it as suggesting reflections
on the subject of these passages. Suggest would
not be understood by any common reason as sy¬
nonymous with revive or rekindle. Defects of
the same sort may indeed be found in the pa¬
rallel phrases of most if not all philosophers,
and all of them proceed from the same source,—
namely, the erroneous but prevalent notion, that
the law of association produces only such a close
union of a thought and a feeling, as gives one
the power of reviving the other; instead of the
truth, that it forms them into a new compound,
in *vdiich the properties of the component parts
are no longer discoverable, and which may itself
become a substantive principle of human nature.
They supposed the condition, produced by its
power, to resemble that of material substances
in a state of mechanical diffusion; whereas in
reality it may be better likened to a chemical
combination of the same substances, from which
a totally new product arises. The language in¬
volves a confusion of the question which relates
to the origin of the principles of human activity,
with the other and far more important question
which relates to their nature; and as soon as
this distinction is hidden, the theorist is either
betrayed into the selfish system by a desire of
clearness and simplicity, or tempted to the need¬
less multiplication of ultimate facts by mistaken
anxiety for what he supposes to be the guards of
our social and moral nature. The defect is com¬
mon to Brown with his predecessors, but in him
less excusable; for he saw the truth and recoil¬
ed from it. .
DISSERTATION SECOND.
417
It is the main defect of the term association
itself, that it does not, without long habit, convey
the notion of a perfect union, but rather leads
to that of a combination which may be dissolved,
if not at pleasure, at least with the help of care
and exertion ; which is utterly and dangerously
false in the important cases where such unions
are considered as constituting the most essential
principles of human nature. Men can no more
dissolve these unions than they can disuse their
habit of judging of distance by the eye, and
often by the ear. But suggestion implies, that
what suggests is separate from what is suggest¬
ed, and consequently negatives that unity in an
active principle which the whole analogy of na¬
ture, as well as our own direct consciousness,
shows to be perfectly compatible with its origin
in composition.
Large concessions are, in the first place, to be
remarked, which must be stated, because they
very much narrow the matter in dispute. Those
who, before Brown, contended against beneficial
tendency as the standard of morality, have
either shut their eyes on the connection of vir¬
tue with general utility; or carelessly and ob¬
scurely allowed, without further remark, a con¬
nection which is at least one of the most re¬
markable and important of ethical facts. He
acts more boldly, and avowedly discusses “ the
relation of virtue to utility.” He was compell¬
ed by that discussion to make those concessions
which so much abridge this controversy. <c Uti¬
lity and virtue are so related, that there is per¬
haps no action generally felt to be virtuous,
which it would not be beneficial that all men in
similar circumstances should imitate.”1 “ In
every case of benefit or injury willingly done,
there arise certain emotions of moral appro¬
bation or disapprobation.” 2 * * “ The intentional
produce of evil, as pure evil, is always hated;
and that of good, as pure good, always loved.”5
All virtuous acts are thus admitted to be uni¬
versally beneficial; morality and the general
benefit are acknowledged always to coincide. It
is hard to say, then, why they should not be re¬
ciprocally tests of each other, though in a very
different way;—the virtuous feelings, fitted as
they are by immediate appearance, by quick and
powerful action, being sufficient tests of mora¬
lity in the moment of action, and for all prac¬
tical purposes; while the consideration of ten¬
dency to general happiness, a more obscure and
slowly discoverable quality, should be applied
in general reasoning, as a test of the sentiments
and dispositions themselves. It has been thus
employed, and no proof has been attempted, that
it has ever deceived those who used it in the pro¬
per place. It has uniformly served to justify our
moral constitution, and to show how reasonable
it is for us to be guided in action by our higher
feelings. At all events it should be, but has not
been considered, that from these concessions alone
it follows, that beneficial tendency is at least one
constant property of virtue. Is not this, in effect,
an admission that beneficial tendency does dis¬
tinguish virtuous acts and dispositions from those
which we call vicious ? If the criterion be in¬
complete or delusive, let its faults be specified,
and let some other quality be pointed out, which,
either singly or in combination with beneficial
tendency, may more perfectly indicate the dis¬
tinction.
But let us not be assailed by arguments which
leave untouched its value as a test, and are in
truth directed only against its fitness as an im¬
mediate incentive and guide to right action. To
those who contend for its use in the latter cha¬
racter, it must be left to defend, if they can, so
untenable a position. But all others must re¬
gard as pure sophistry the use of arguments
against it as a test, which really show nothing
more than its acknowledged unfitness to be a
motive.
When voluntary benefit and voluntary injury
are pointed out as the main, if not the sole ob¬
jects of moral approbation and disapprobation,—
when we are told truly, that the production of
good, as good, is always loved, and that of evil,
1 Lectures, vol. IV. p. 45. The unphilosophical word “ perhaps” must be struck out of the proposition, unless the
whole be considered as a mere conjecture. It limits no affirmation, but destroys it, by converting it into a guess. See the
like concession, vol. IV. p. 33, with some words interlarded, which betray a sort of reluctance and fluctuation, indicative of
the difficulty with which Brown struggled to withhold his assent from truths which he unreasonably dreaded.
* Hid, vol. III. p. 567-
1 Hid. vol. III. p, 621.
DISS. II. 3 G
418
PRELIMINARY DISSERTATIONS.
as such, always hated,—can we require a more
clear, short, and unanswerable proof, that bene¬
ficial tendency is an essential quality of virtue ?
It is indeed an evidently necessary consequence
of this statement, that if benevolence he amiable
in itself, our affection for it must increase with
its extent; and that no man can he in a per¬
fectly right state of mind, who, if he consider
general happiness at all, is not ready to acknow¬
ledge that a good man must regard it as being
in its own nature the most desirable of all objects,
however the constitution and circumstances of
human nature may render it unfit or impossible
to pursue it directly as the object of life. It is
at the same time apparent that no such man
can consider any habitual disposition, clearly
discerned to be in its whole result at variance
with general happiness, as not unworthy of being
cultivated, or as not fit to be rooted out. It is
manifest that, if it were otherwise, he would
cease to be benevolent. As soon as we conceive
the sublime idea of a Being who not only fore¬
sees, but commands, all the consequences of the
actions of all voluntary agents, this scheme of
reasoning appears far more clear. In such a
case, if our moral sentiments remain the same,
they compel us to attribute his whole govern¬
ment of the world to benevolence. The conse¬
quence is as necessary as in any process of rea¬
son ; for if our moral nature be supposed, it
will appear self-evident, that it is as much im¬
possible for us to love and revere such a Being,
if we ascribe to him a mixed or imperfect bene¬
volence, as to believe the most positive contra¬
diction in terms. Now, as religion consists in
that love and reverence, it is evident that it can¬
not subsist without a belief in benevolence as
the sole principle of divine government. It is
nothing to tell us that this is not a process of
icasoning, or, to speak more exactly, that the
first propositions are assumed. The first propo¬
sitions in every discussion relating to intellectual
operations must likewise be assumed. Con¬
science is not reason, but it is not less an es¬
sential part of human nature than reason. Prin¬
ciples which are essential to all its operations
are as much entitled to immediate and implicit
assent, as those principles which stand in the
same relation to the reasoning faculties. The
laws prescribed by a benevolent Being to his
creatures must necessarily be founded on the
principle of promoting their happiness. It would
be singular indeed, if the proofs of the goodness
of God, legible in every part of nature, should
not, above all others, be most discoverable and
conspicuous in the beneficial tendency of his
moral laws.
But we are asked, if tendency to general wel¬
fare be the standard of virtue, why is it not al¬
ways present to the contemplation of every man
who does or prefers a virtuous action ? Must
not utility be in that case cc the felt essence of
virtue ?”1 Why are other ends, besides general
happiness, fit to be morally pursued ?
These questions, which are all founded on
that confusion of the theory of actions with the
theory of sentiments, against which the reader
was so early warned,2 might be dismissed with
no more than a reference to that distinction from
the forgetfulness of which they have arisen. By
those advocates of utility, indeed, who hold it to
be a necessary part of their system, that some
glimpse at least of tendency to personal or ge¬
neral wellbeing is an essential part of the mo¬
tives which render an action virtuous, these
questions cannot be satisfactorily answered.
Against such they are arguments of irresistible
force; but against the doctrine itself, rightly
understood and justly bounded, they are alto¬
gether powerless. The reason why there may,
and must be, many ends morally more fit to be
pursued in practice than general happiness, is
plainly to be found in the limited capacity of
man. A perfectly good Being, who foresees and
commands all the consequences of action, can¬
not indeed be conceived by us to have any other
end in view than general wellbeing Why evil
exists under that perfect government, is a ques¬
tion towards the solution of which the human
understanding can scarcely advance a single step.
But all who hold the evil to exist only for good,
and own their inability to explain why or how,
1 Lectures, vol. IY. p. 38.
s See supra, p. 313-315.
DISSERTATION SECOND.
419
are perfectly exempt from any charge of incon¬
sistency in their obedience to the dictates of their
moral nature. The measure of the faculties of
man renders it absolutely necessary for him to
have many other practical ends; the pursuit of
all of which is moral, when it actually tends to
general happiness, though that last end never
entered into the contemplation of the agent. It
is impossible for us to calculate the effects of a
single action, any more than the chances of a
single life. But let it not be hastily concluded,
that the calculation of consequences is impossible
in moral subjects. To calculate the general
tendency of every sort of human action, is a
possible, easy, and common operation. The ge¬
neral good effects of temperance, prudence, for¬
titude, justice, benevolence, gratitude, veracity,
fidelity,—of the affections of kindred, and of love
for our country,—are the subjects of calculations
which, taken as generalities, are absolutely un¬
erring. They are founded on a larger and firmer
basis of more uniform experience, than any of
those ordinary calculations which govern pru¬
dent men in the whole business of life. An
appeal to these daily and familiar transactions
furnishes at once a decisive answer, both to
those advocates of utility who represent the con¬
sideration of it as a necessary ingredient in vir¬
tuous motives, as well as moral approbation,
and to those opponents who turn the unwar¬
rantable inferences of unskilful advocates into
proofs of the absurdity into which the doctrine
leads.
The cultivation of all the habitual sentiments
from which the various classes of virtuous actions
flow—the constant practice of such actions—
the strict observance of rules in all that province
of Ethics which can be subjected to rules—the
watchful care of all the outworks of every part
of duty, of that descending series of useful ha¬
bits which, being securities to virtue, become
themselves virtues,—are so many ends which
it is absolutely necessary for man to pursue and
to seek for their own sake.
“ I saw D’Alembert,” says a very late writer,
“ congratulate a young man very coldly, who
brought him a solution of a problem. The young
man said, ‘ I have done this in order to have a
seat in the Academy.’ ‘ Sir,’ answered D’Alem¬
bert, ‘ with such dispositions you never will earn
one. Science must be loved for its own sake,
and not for the advantage to be derived. No
other principle will enable a man to make pro¬
gress in the sciences.’ ”1 It is singular that
D’Alembert should not perceive the extensive
application of this truth to the whole nature of
man. No man can make progress in a virtue
who does not seek it for its own sake. No man
is a friend, a lover of his country, a kind father,
a dutiful son, who does not consider the culti¬
vation of affection and the performance of duty
in all these cases respectively as incumbent on
him for their own sake, and not for the advan¬
tage to be derived from them. Whoever serves
another with a view of advantage to himself is
universally acknowledged not to act from affec¬
tion. But the more immediate application of
this truth to our purpose is, that in the case of
those virtues which are the means of cultivating
and preserving other virtues, it is necessary to
acquire love and reverence for the secondary
virtues for their own sake, without which they
never will be effectual means of sheltering and
strengthening those intrinsically higher qualities
to which they are appointed to minister. Every
moral act must be considered as an end, and men
must banish from their practice the regard to
the most naturally subordinate duty as a means.
Those who are perplexed by the supposition
that secondary virtues, making up by the extent
of their beneficial tendency for what in each
particular instance they may want in magnitude,
may become of as great importance as the pri¬
mary virtues themselves, would do well to con¬
sider a parallel though very homely case. A
house is useful for many purposes: many of
these purposes are in themselves, for the time,
more important than shelter. The destruction
of the house may, nevertheless, become a greater
evil than the defeat of several of these purposes,
because it is permanently convenient, and indeed
necessary to the execution of most of them. A
1 Memoires de Montlosier, vol. I. p. 50.
420
PRELIMINARY DISSERTATIONS.
floor is made for warmth, for dryness—to sup¬
port tables, chairs, beds, and all the household
implements which contribute to accommodation
and to pleasure. The floor is valuable only as
a means; hut, as the only means by which many
ends are attained, it maybe much more valuable
than some of them. The table might be, and
generally is, of more valuable timber than the
floor; hut the workman who should for that rea¬
son take more pains in making the table strong
than the floor secure would not long he employ¬
ed by customers of common sense. The connec¬
tion of that part of morality which regulates the
intercourse of the sexes with benevolence, affords
the most striking instance of the very great im¬
portance which may belong to a virtue, in itself
secondary, hut on which the general cultivation
of the highest virtues permanently depends.
Delicacy and modesty may he thought chiefly
worthy of cultivation, because they guard purity;
hut they must he loved for their own sake, with¬
out which they cannot flourish. Purity is the
sole school of domestic fidelity, and domestic
fidelity is the only nursery of the affections be¬
tween parents and children, from children to¬
wards each other, and, through these affections,
of all the kindness which renders the world habit¬
able. At each step in the progress, the appropriate
end must he loved for its own sake; and it is easy
to see how the only means of sowing the seeds
of benevolence, in all its forms, may become of
far greater importance than many of the modi¬
fications and exertions even of benevolence it¬
self. To those who will consider this subject,
it will not long seem strange that the sweetest
and most gentle affections grow up only under
the apparently cold and dark shadow of stern
duty. The obligation is strengthened, not weak¬
ened, by the consideration that it arises from
human imperfection; which only proves it to
be founded on the nature of man. It is enough
that the pursuit of all these separate ends leads
to general wellbeing, the promotion of which is
the final purpose of the creation.
The last and most specious argument against
beneficial tendency, even as a test, is conveyed in
the question, why moral approbation is not be¬
stowed on every thing beneficial, instead of be¬
ing confined, as it confessedly is, to voluntary
acts. It may plausibly be said, that the esta¬
blishment of the beneficial tendency of all those
voluntary acts which are the objects of moral
approbation is not sufficient, since, if such ten¬
dency be the standard, it ought to follow, that
whatever is useful should also be morally ap¬
proved. To answer, as has before been done,1
that experience gradually limits moral approba¬
tion and disapprobation to voluntary acts, by
teaching us that they influence the will, but are
wholly wasted if they he applied to any other
object,—though the fact be true, and contributes
somewhat to the result, is certainly not enough.
It is at best a partial solution. Perhaps, on re¬
consideration, it is entitled only to a secondary
place. To seek a foundation for universal, ar¬
dent, early, and immediate feelings, in processes
of an intellectual nature, has, since the origin of
philosophy, been the grand error of ethical in¬
quirers into human nature. To seek for such a
foundation in association, an early and insen¬
sible process, which confessedly mingles itself
with the composition of our first and simplest
feelings, and which is common to both parts
of our nature, is not liable to the same ani¬
madversion. If conscience he uniformly pro¬
duced by the regular and harmonious co-opera¬
tion of many processes of association, the ob¬
jection is in reality a challenge to produce a
complete theory of it, founded on that princi¬
ple, by exhibiting such a full account of all
these processes as may satisfactorily explain why
it proceeds thus far and no farther. This
would he a very arduous attempt, and perhaps
it may be premature. But something may be
more modestly tried towards an outline^ which,
though it might leave many particulars unex¬
plained, may justify a reasonable expectation
that they are not incapable of explanation; and
may even now assign such reasons for the limi¬
tation of approbation to voluntary acts, as may
convert the objection derived from that fact into
a corroboration of the doctrines to which it has
1 See supra, p. 372, 373.
DISSERTATION SECOND,
i
421
been opposed as an insurmountable difficulty.
Such an attempt will naturally lead to the close
of the present Dissertation. The attempt has
indeed been already made,1 hut not without
great apprehensions on the part of the author
that he has not been clear enough, especially in
those parts which appeared to himself to owe
most to his own reflection. He will now en¬
deavour, at the expense of some repetition, to he
more satisfactory.
There must be primary pleasures, pains, and
even appetites, which arise from no prior state
of mind, and which, if explained at all, can he
derived only from bodily organization; for if
there were not, there could he no secondary de¬
sires. What the number of the underived prin¬
ciples may be, is a question to which the an¬
swers of philosophers have been extremely va¬
rious, and of which the consideration is not
necessary to our present purpose. The rules
of philosophizing, however, require that causes
should not he multiplied without necessity. Of
two explanations, therefore, which give an
equally satisfactory account of appearances, that
theory is manifestly to be preferred which sup¬
poses the smaller number of ultimate and inex¬
plicable principles. This maxim, it is true, is
subject to three indispensable conditions. 1.
That the principles employed in the explanation
should he known really to exist: in which con¬
sists the main distinction between hypothesis and
theory. Gravity is a principle universally known
to exist; ether and a nervous fluid are mere
suppositions. 2. That these principles should
be known to produce effects like those which
are ascribed to them in the theory. This is
a further distinction between hypothesis and
theory; for there are an infinite number of de¬
grees of likeness, from the faint resemblances
which have led some to fancy that the functions
of the nerves depend on electricity, to the re¬
markable coincidences between the appearances
of projectiles on earth, and the movements of
the heavenly bodies, which constitutes the New¬
tonian system; a theory now perfect, though
exclusively founded on analogy, and in which
one of the classes of phenomena brought toge¬
ther by it is not the subject of direct experience.
3. That it should correspond, if not with all the
facts to he explained, at least with so great a
majority of them as to render it highly proba¬
ble that means will in time he found of reconcil¬
ing it to all. It is only on this ground that the
Newtonian system justly claimed the title of a
legitimate theory during that long period when
it was unable to explain many celestial appear¬
ances, before the labours of a century, and the
genius of Laplace, at length completed the
theory, by adapting it to all the phenomena. A
theory may he just before it is complete.
In the application of these canons to the
theory which derives most of the principles of
human action from the transfer of a small num¬
ber of pleasures, perhaps organic, by the law of
association to a vast variety of new objects, it
cannot he denied, 1st, That it satisfies the first of
the above conditions, inasmuch as association is
really one of the laws of human nature; 2dly,
That it also satisfies the second, for association
certainly produces effects like those which are
referred to it by this theory, otherwise there
would be no secondary desires, no acquired re¬
lishes and dislikes;—facts universally acknow¬
ledged, which are and can he explained only by
the principle called by Hobbes mental discourse;
—by Locke, Hume, Hartley, Condillac, and the
majority of speculators, as well as in common
speech, association;—by Tucker, translation ;—
and by Brown, suggestion. The facts generally
referred to the principle resemble those which
are claimed for it by the theory in this important
particular, that in both cases equally, pleasure
becomes attached to perfectly new things, so
that the derivative desires become perfectly in¬
dependent on the primary. The great dissimi¬
larity of these two classes of passions has been
supposed to consist in this, that the former al¬
ways regards the interest of the individual, while
the latter regards the welfare of others. The
philosophical world has been almost entirely di¬
vided into two sects; the partisans of selfishness,
comprising mostly all the predecessors of Butler,
1 See supra, p. 362-3, 381-5-.
422
PRELIMINARY DISSERTATIONS.
and the greater part of his successors; and the
advocates of benevolence, who have generally
contended that the reality of disinterestedness de¬
pends on its being a primary principle. Enough
has been said by Butler against the more fa¬
tal heresy of selfishness. Something has al¬
ready been said against the error of the ad¬
vocates of disinterestedness, in the progress of
this attempt to develope ethical truths histo¬
rically, in the order in which inquiry and con¬
troversy brought them out with increasing
brightness. The analogy of the material world
is indeed faint, and often delusive; yet we
dare not utterly reject that on which the whole
technical language of mental and moral science
is necessarily grounded. The whole creation
teems with instances where the most powerful
agents and the most lasting bodies are the ac¬
knowledged results of the composition, some¬
times of a few, often of many elements. These
compounds often in their turn become the ele¬
ments of other substances ; and it is with them
that we are conversant chiefly in the pursuits of
knowledge, solely in the concerns of life. No
man ever fancied, that because they were com¬
pounds, they were therefore less real. It is
impossible to confound them with any of the
separate elements which contribute towards
their formation. But a much more close resem¬
blance presents itself. Every secondary desire,
or acquired relish, involves in it a transfer of
pleasure to something which was before indiffer¬
ent or disagreeable. Is the new pleasure the
less real for being acquired ? Is it not often pre¬
ferred to the original enjoyment ? Are not many
of these secondary pleasures indestructible ? Do
not many of them survive primary appetites ?
Lastly, the important principle of regard to
our own general welfare, which disposes us to
prefer it to immediate pleasure, unfortunately
called self-love (as if, in any intelligible sense of
the term love, it were possible for a man to love
himself), is perfectly intelligible if its origin he
ascribed to association, hut utterly incompre¬
hensible if it he considered as prior to the appe¬
tites and desires, which alone furnish it with
materials. As happiness consists of satisfactions,
self-love presupposes appetites and desires which
are to be satisfied. If the order of time were
important, the affections are formed at an earlier
period than many self-regarding passions, and
they always precede the formation of self-love.
Many of the later advocates of the disinterest¬
ed system, though recoiling from an apparent
approach to the selfishness into which the purest
of their antagonists had occasionally fallen,
were gradually obliged to make concessions to
the derivative system, though clogged with the
contradictory assertion, that it was only a refine¬
ment of selfishness: and we have seen that
Brown, the last and not the least in genius of
them, has nearly abandoned the greater, though
not indeed the most important part of the terri¬
tory in dispute, and scarcely contends for any
underived principle hut the moral faculty.
In this state of opinion among the very small
number in Great Britain who still preserve some
remains of a taste for such speculations, it is
needless here to trace the application of the law
of association to the formation of the secondary
desires, whether private or social. For our pre¬
sent purposes, the explanation of their origin
may be assumed to he satisfactory. In what
follows, it must, however, he steadily borne in
mind, that this concession involves an admission
that the pleasure derived from low objects may
be transferred to the most pure; that from a
part of a self-regarding appetite such a pleasure
may become a portion of a perfectly disinterest¬
ed desire; and that the disinterested nature and
absolute independence of the latter are not in
the slightest degree impaired by the considera¬
tion, that it is formed by one of those grand
mental processes to which the formation of the
other habitual states of the human mind have
been, with great probability, ascribed.
When the social affections are thus formed,
they are naturally followed in every instance by
the will to do whatever can promote their object.
Compassion excites a voluntary determination
to do whatever relieves the person pitied. The
like process must occur in every case of grati¬
tude, generosity, and affection. Nothing so
uniformly follows the kind disposition as the act
of will, because it is the only means by which
the benevolent desire can be gratified. The re¬
sult of what Brown justly calls “afiner analysis,”
shows a mental contiguity of the affection to the
DISSERTATION SECOND.
423
volition to be much closer than appears on a
coarser examination of this part of our nature.
No wonder, then, that the strongest association,
the most active power of reciprocal suggestion,
should subsist between them. As all the affec¬
tions are delightful, so the volitions, voluntary
acts which are the only means of their gratifica¬
tion, become agreeable objects of contemplation
to the mind. The habitual disposition to per¬
form them is felt in ourselves, and observed in
others, with satisfaction. As these feelings be¬
come more lively, the absence of them may be
viewed in ourselves with a pain, in others with
an alienation capable of indefinite increase. They
become entirely independent sentiments; still,
however, receiving constant supplies of nourish¬
ment from their parent affections, which, in
well-balanced minds, reciprocally strengthen
each other; unlike the unkind passions, which
are constantly engaged in the most angry con¬
flicts of civil war. In this state we desire to
experience these beneficent volitions, to cultivate
a disposition towards them, and to do every cor¬
respondent voluntary act. They are for their own
sake the objects of desire. They thus constitute
a large portion of those emotions, desires, and
affections, which regard certain dispositions of
the mind and determinations of the will as their
sole and ultimate end. These are what are called
the moral sense, the moral sentiments, or best
though most simply, by the ancient name of Con¬
science; which has the merit, in our language, of
being applied to no other purpose, which pecu¬
liarly marks the strong working of these feelings
on conduct, and which, from its solemn and sacred
character, is well adapted to denote the vener¬
able authority of the highest principle of human
nature.
Nor is this all: It has already been seen that
not only sympathy with the sufferer, hut indig¬
nation against the wrong-doer, contributes a
large and important share towards the moral
feelings. We are angry at those who disappoint
our wish for the happiness of others. We make
the resentment of the innocent person wronged
our own. Our moderate anger approves all
well-proportioned punishment of the wrong-doer.
We hence approve those dispositions and actions
of voluntary agents which promote such suitable
punishment, and disapprove those which hinder
its infliction or destroy its effect; at the head
of which may he placed that excess of punish¬
ment beyond the average feelings of good men
which turns the indignation of the calm by¬
stander against the culprit into pity. In this
state, when anger is duly moderated,—when
it is proportioned to the wrong,—when it is
detached from personal considerations,—when
dispositions and actions are its ultimate objects,—it
becomes a sense of justice, and is so purified as
to he fitted to be a new element of conscience.
There is no part of morality which is so directly
aided by a conviction of the necessity of its ob¬
servance to the general interest, as justice. The
connection between them is discoverable by the
most common understanding. All public deli¬
berations profess the public welfare to he their
object; all laws propose it as their end. This
calm principle of public utility serves to me¬
diate between the sometimes repugnant feelings
which arise in the punishment of criminals,
by repressing undue pity on one hand, and re¬
ducing resentment to its proper level on the
other. Hence the unspeakable importance of
criminal laws as a part of the moral education
of mankind. Whenever they carefully conform
to the moral sentiments of the age and country,
—when they are withheld from approaching the
limits within which the disapprobation of good
men would confine punishment, they contribute
in the highest degree to increase the ignominy
of crimes, to make men recoil from the first sug¬
gestions of criminality, and to nourish and ma¬
ture the sense of justice, which lends new vigour
to the conscience with which it has been united.
Other contrihutary streams present them¬
selves. Qualities which are necessary to virtue,
but may he subservient to vice, may, independ¬
ently of that excellence or of that defect, he in
themselves admirable. Courage, energy, deci¬
sion, are of this nature. In their wild state
they are often savage and destructive. When
they are tamed by the society of the affections,
and trained up in obedience to the moral facul¬
ty, they become virtues of the highest order,
and, by their name of magnanimity, proclaim
the general sense of mankind that they are the
characteristic qualities of a great soul. They
424
PRELIMINARY DISSERTATIONS.
retain whatever was admirable in their unre¬
claimed state, together with all that they borrow
from their new associate and their high ruler.
Their nature, it must be owned, is prone to
evil; but this propensity does not hinder them
from being rendered capable of being ministers
of good, in a state where the gentler virtues re¬
quire to be vigorously guarded against the attacks
of daring depravity. It is thus that the strength
of the well-educated elephant is sometimes em¬
ployed in vanquishing the fierceness of the tiger,
and sometimes used as a means of defence against
the shock of his brethren of the same species.
The delightful contemplation, however, of these
qualities, when purely applied, becomes one of the
sentiments of which the dispositions and actions
of voluntary agents are the direct and final object.
By this resemblance they are associated with
the other moral principles, and with them con¬
tribute to form Conscience, which, as the master
faculty of the soul, levies such large contribu¬
tions on every province of human nature.
It is important, in this point of view, to con¬
sider also the moral approbation which is un¬
doubtedly bestowed on those dispositions and ac¬
tions of voluntary agents which terminate in their
own satisfaction, security, and wellbeing. They
have been called duties to ourselves, as absurd¬
ly as a regard to our own greatest happiness is
called self-love. But it cannot be reasonably
doubted, that intemperance, improvidence, ti¬
midity, even when considered only in relation
to the individual, are not only regretted as im¬
prudent, but blamed as morally wrong. It was
excellently observed by Aristotle, that a man is
not commended as temperate, so long as it costs
him efforts of self-denial to persevere in the
practice of temperance, but only when he pre¬
fers that virtue for its own sake. He is not meek,
nor brave, as long as the most vigorous self-
command is necessary to bridle his anger or his
fear. On the same principle, he may be judi¬
cious or prudent; but he is not benevolent if he
confers benefits with a view to his own greatest
happiness. In like manner, it is ascertained by
experience, that all the masters of science and
of art—that all those who have successfully
pursued truth and knowledge—love them for
their own sake, without regard to the gene¬
rally imaginary dower of interest, or even to
the dazzling crown which fame may place on
their heads.1 But it may still be reasonably
asked, why these useful qualities are morally im¬
proved, and how they become capable of being
combined with those public and disinterested
sentiments which principally constitute con¬
science ? The answer is, because they are en¬
tirely conversant with volitions and voluntary
actions, and in that respect resemble the other
constituents of conscience, with which they are
thereby fitted to mingle and coalesce. Like
those other principles, they may be detached
from what is personal and outward, and fixed on
the dispositions and actions, which are the only
means of promoting their ends. The sequence
of these principles and acts of will becomes so fre¬
quent, that the association between both may be
as firm as in the former cases. All those senti¬
ments of which the final object is astate of the will,
become thus intimately and inseparably blended;
and of that perfect state of solution (if such
words may be allowed) the result is Conscience
—the judge and arbiter of human conduct ;
which, though it does not supersede ordinary mo¬
tives of virtuous feelings and habits, which are
the ordinary motives of good actions, yet exer¬
cises a lawful authority even over them, and
ought to blend with them. Whatsoever actions
and dispositions are approved by conscience
acquire the name of virtues or duties : they are
pronounced to deserve commendation; and we
are justly considered as under amoral obligation to
practise the actions and cultivate the dispositions.
The coalition of the private and public feel-
1 See the Pursuit of Knowledge under Difficulties, a discourse forming the first part of the third volume of the Lilrary of
Entertaining Knowledge, London, 1829. The author of this Essay, for it can be no other than Mr Brougham, will by others
be placed at the head of those who, in the midst of arduous employments, and surrounded by all the allurements of society,
yet find leisure for exeiting the unwearied vigour of their minds in every mode of rendering permanent service to the hu¬
man species ; more especially in spreading a love of knowledge, and diffusing useful truth among all classes of men. These
voluntary occupations deserve our attention still less as examples of prodigious power than as proofs of an intimate con¬
viction, which hinds them by unity of purpose with his public duties, that (to use the almost dying words of an excellent
person) “ man can neither be happy without virtue, nor actively virtuous without liberty, nor securely free without rational
knowledge.” (Close of Sir W. Jones’s last Discourse to th£ Asiatic Society of Calcutta^)
DISSERTATION SECOND.
425
ings is very remarkable in two points of view,
from which it seems hitherto to have been scarce¬
ly observed. First, It illustrates very forcibly
all that has been here offered to prove, that the
peculiar character of the moral sentiments con¬
sists in their exclusive reference to states of will,
and that every feeling which has that quality,
when it is purified from all admixture with dif¬
ferent objects, becomes capable of being absorb¬
ed into Conscience, and of being assimilated to
it, so as to become a part of it. For no feelings
can be more unlike each other in their object
than the private and the social; and yet, as both
employ voluntary actions as their sole immedi¬
ate means, both may be transferred by associa¬
tion to states of the will, in which case they are
transmuted into moral sentiments. No exam¬
ple of the coalition of feelings in their general
nature less widely asunder, could afford so much
support to this position. Secondly, By raising
qualities useful to ourselves to the rank of virtues,
it throws a strong light on the relation of virtue
to individual interest; very much as justice illus¬
trates the relation of morality to general interest.
The coincidence of morality with individual inte¬
rest is an important truth in Ethics. It is most
manifest in that part of Ethics which we are
now considering. A calm regard to our general
interest is indeed a faint and infrequent motive
of action. Its chief advantage is, that it is re¬
gular, and that its movements may be calculat¬
ed. In deliberate conduct it may often be relied
on, though perhaps never safely without know¬
ledge of the whole temper and character. But
in moral reasoning at least, the coincidence is
of unspeakable advantage. If there be a miser¬
able man who has cold affections, a weak sense
of justice, dim perceptions of right and wrong,
and faint feelings of them;—if, still more wretch¬
ed, his heart be constantly torn and devoured by
malevolent passions—the vultures of the soul;
—we have one resource still left, even in cases
so dreadful. Even he still retains a human
principle, to which we can speak. He must
own that he has some wish for his own lasting
welfare. We can prove to him that his state of
mind is inconsistent with it. It may be impos¬
sible indeed to show, that while his disposition
continues the same, he can derive any enjoy¬
ment from the practice of virtue. But it may
be most clearly shown, that every advance in the
amendment of that disposition is a step towards
even temporal happiness. If he do not amend
his character, we may compel him to own that
he is at variance with himself, and offends against
a principle of which even he must recognise the
reasonableness.
The formation of Conscience from so many
elements, and especially the combination of ele¬
ments so unlike as the private desires and the
social affections, early contributes to give it the
appearance of that simplicity and independence
which in its mature state really distinguish it.
It becomes, from these circumstances, more dif¬
ficult to distinguish its separate principles ; and
it is impossible to exhibit them in separate ac¬
tion. The affinity of these various passions to
each other, which consists in their having no ob¬
ject but states of the will, is the only common pro¬
perty which strikes the mind. Hence the faci¬
lity with which the general terms, first probably
limited to the relations between ourselves and
others, are gradually extended to all voluntary
acts and dispositions. Prudence and temper¬
ance become the objects of moral approbation.
When imprudence is immediately disapproved
by the by-stander, without deliberate considera¬
tion of its consequences, it is not only displeas¬
ing, as being pernicious, but it is blamed as
wrong, though with a censure so much inferior
to that bestowed on inhumanity and injustice, as
may justify those writers who ilse the milder
term improper. At length, when the general
words come to signify the objects of moral ap¬
probation, and the reverse, they denote merely
the power to excite feelings which are as inde¬
pendent as if they were underived, and which
coalesce the more perfectly, because they are de¬
tached from objects so various and unlike as to
render their return to their primitive state very
difficult.
The question,1 why we do not morally approve
the useful qualities of actions which are altogether
involuntary, may now be shortly and satisfacto-
3 H
DISS. II.
1 See supra, p. 363.
426
preliminary dissertations.
rily answered: because conscience is in perpe¬
tual contact, as it were, with all the dispositions
and actions of voluntary agents, and is hy that
means indissolubly associated with them exclu¬
sively. It has a direct action on the will, and a
constant mental contiguity to it. It has no such
mental contiguity to involuntary changes. It
has never perhaps been observed, that an opera¬
tion of the conscience precedes all acts deliber¬
ate enough to he in the highest sense voluntary,
and does so as much when it is defeated as when
it prevails. In either case the association is re¬
peated. It extends to the whole of the active
man. All passions have a definite outward ob¬
ject to which they tend, and a limited sphere
within which they act. But conscience has no
object but a state of will; and as an act of will
is the sole means of gratifying any passion,
conscience is co-extensive with the whole man,
and without encroachment curbs or aids every
feeling, even within the peculiar province of that
feeling itself. As will is the universal means,
conscience, which regards will, must he a uni¬
versal principle. As nothing is interposed be¬
tween conscience and the will when the mind is
in its healthy state, the dictate of conscience is
followed by the determination of the will, with a
promptitude and exactness which very naturally
is likened to the obedience of an inferior to the
lawful commands of those whom he deems to he
rightfully placed over him. It therefore seems
clear, that on the theory which has been attempt¬
ed, moral approbation must he limited to volun¬
tary operations, and conscience must he universal,
independent, and commanding.
One remaining difficulty may perhaps he ob¬
jected to the general doctrines of this Disserta¬
tion, though it does not appear at any time to
have been urged against other modifications of
the same principle. “If moral approbation,” it
may he said, “ involve no perception of beneficial
tendency, whence arises the coincidence between
that principle and the moral sentiments ?” It
may seem at first sight, that such a theory rests
the foundation of morals upon a coincidence al¬
together mysterious, and apparently capricious
and fantastic. Waiving all other answers, let
us at once proceed to that which seems conclusive.
It is true that conscience rarelj contemplates so
distant an object as the welfare of all sentient
beings. But to what point is every one of its
elements directed ? What, for instance, is the
aim of all the social affections? Nothing hut the
production of larger or smaller masses of happi¬
ness among those of our fellow-creatures who
are the objects of these affections. In every case
these affections promote happiness, as far as their
foresight and their power extend. What can he
more conducive, or even necessary, to the being
and wellbeing of society, than the rules of justice ?
Are not the angry passions themselves, as far as
they are ministers of morality, employed in re¬
moving hinderances to the welfare of ourselves
and others, which is indirectly promoting it?
The private passions terminate indeed in the
happiness of the individual, which, however, is
a part of general happiness, and the part over
which we have most power. Every principle of
which conscience is composed has some portion
of happiness for its object. To that point they
all converge. General happiness is not indeed
one of the natural objects of conscience, because
our voluntary acts are not felt and perceived to
affect it. But how small a step is left for rea¬
son. It only casts up the items of the account.
It has only to discover that the acts of those who
labour to promote separate portions of happiness
must increase the amount of the whole. It may
he truly said, that if observation and experience
did not clearly ascertain that beneficial tendency
is the constant attendant and mark of all virtu¬
ous dispositions and actions, the same great
truth would he revealed to us hy the voice of
conscience. The coincidence, instead of being
arbitrary, arises necessarily from the laws of
human nature, and the circumstances in which
mankind are placed. We perform and approve
virtuous actions, partly because conscience re¬
gards them as right, partly because we are
prompted to them hy good affections. All these
affections contribute towards general wellbeing,
though it were not necessary, nor would it he
fit, that the agent should be distracted hy the
contemplation of that vast and remote object.
The various relations of conscience to religion
we have already been led to consider on the
principles of Butler, of Berkeley, of Paley, and
especially of Hartley, who was led hy his own
DISSERTATION SECOND.
427
piety to contemplate as the last and highest
stage of virtue and happiness, a sort of self-
annihilation, which, however unsuitable to the
present condition of mankind, yet places in the
strongest light the disinterested character of the
system, of which it is a conceivable though
perhaps not attainable result. The complete¬
ness and rigour acquired by conscience, when all
its dictates are revered as the commands of a
perfectly wise and good Being, are so obvious,
that they cannot he questioned by any reason¬
able man, however extensive his incredulity may
be. It is thus that conscience can add the
warmth of an affection to the inflexibility of
principle and habit. It is true that, in exa¬
mining the evidence of the divine original of a
religious system, in estimating an imperfect re¬
ligion, or in comparing the demerits of religions
of human origin, conscience must he the stand¬
ard chiefly applied. But it follows with equal
clearness, that those who have the happiness to
find satisfaction and repose in divine revela¬
tion, are bound to consider all those precepts
for the government of the will, delivered by
it, which are manifestly universal, as the rules
to which all their feelings and actions should
conform. The true distinction between con¬
science and a taste for moral beauty has already
been pointed out;1 a distinction which, not¬
withstanding its simplicity, has been unobserved
by philosophers, perhaps on account of the fre¬
quent co-o-peration and intermixture of the two
feelings. Most speculators have either denied
the existence of the taste, or kept it out of view
in their theory, or exalted it to the place which
is rightfully filled only by conscience. Yet it
is perfectly obvious that, like all the other feel¬
ings called pleasures of imagination, it termi¬
nates in delightful contemplation, while the
moral faculty always aims exclusively at volun¬
tary action. Nothing can more clearly show
that this last quality is the characteristic of con¬
science, than its being thus found to distinguish
that faculty from the sentiments which most
nearly resemble it, most frequently attend it,
and are most easily blended with it.
Some attempt has now been made to develope
the fundamental principles of ethical theory, in
that historical order in which meditation and
discussion brought them successively into a
clearer light. That attempt, as far as it re¬
gards Great Britain, is at least chronologically
complete. The spirit of bold speculation, con¬
spicuous among the English of the seventeenth
century, languished after the earlier part of
the eighteenth, and seems, from the time of
Hutcheson, to have passed into Scotland, where
it produced Hume, the greatest of sceptics,
and Smith, the most eloquent of modern mo¬
ralists; besides giving rise to that sober, mo¬
dest, perhaps timid Philosophy, which is com¬
monly called Scotch,—which has the singular
merit of having first strongly and largely in¬
culcated the absolute necessity of admitting
certain principles as the foundation of all rea¬
soning, and as being the indispensable con¬
ditions of thought itself. In the eye of the
moralist, all the philosophers of Scotland, Hume
and Smith as much as Reid, Campbell, and
Stewart, have also the merit of having avoid¬
ed the selfish system; and of having, under
whatever variety of representation, alike main¬
tained the disinterested nature of the social af¬
fections and the supreme authority of the moral
sentiments. Brown reared the standard of re¬
volt against the masters of the Scottish School,
and in reality, still more than in words, adopt¬
ed those very doctrines against which his pre¬
decessors, after their war against scepticism,
uniformly combated. The law of association,
though expressed in other language, became
the nearly universal principle of his system;
and perhaps it would have been absolutely
universal if he had not been restrained rather
by respectful feelings than by cogent reasons.
With him the love of speculative philosophy,
as a pursuit, appears to have expired in Scot¬
land. There are some symptoms, yet how¬
ever very faint, of the revival of a taste for it
among the English youth. It was received with
approbation in France from M. Royer Collard,
the scholar of Stewart more than of Reid, and
1 See supra, p. 384, 385.
428
PRELIMINARY DISSERTATIONS.
with enthusiasm from his pupil and successor
M. Cousin, who has clothed the doctrines of the
Schools of Germany in an unwonted eloquence,
which always adorns, hut sometimes disguises
them.
The history of Political Philosophy, even if
its extent and subdivisions were better defined,
would, it is manifest, have occupied another Dis¬
sertation, at least equal in length to the present.
The most valuable parts of it belong to Civil
History. It is too often tainted by a turbulent
and factious spirit to he easily combined with
the calmer history of the progress of science, or
even of the revolutions of speculation. In no
age of the world were its principles so inter¬
woven with political events, and so deeply im¬
bued with the passions and divisions excited by
them, as in the eighteenth century.
It was at one time the purpose, or rather per¬
haps hope, of the writer, to close this discourse
by an account of the ethical systems which have
prevailed in Germany during the last half cen¬
tury; which, maintaining the same spirit amidst
great changes of technical language, and even
of speculative principle, have now exclusive pos¬
session of Europe to the north of the Rhine,
have been welcomed by the French youth with
open arms, have roused in some measure the
languishing genius of Italy, but are still little
known and unjustly estimated by the mere
English reader. He found himself, however,
soon reduced to the necessity of either being su¬
perficial, and by consequence uninstructive; or
of devoting to that subject a far longer time than
he can now spare, and a much larger space than
the limits of this work would probably allow.
The majority of readers will indeed he more
disposed to require an excuse for the extent of
what has been done, than for the relinquishment
of projected additions. All readers must agree
that this is peculiarly a subject on which it is
better to he silent than to say too little.
A very few observations, however, on the Ger¬
man Philosophy, as far as relates to its ethical
hearings and influence, may perhaps he pardoned.
These remarks are not so much intended to he
applied to the moral doctrines of that school,
considered in themselves, as to those apparent de¬
fects in the prevailing systems of Ethics through¬
out Europe, which seem to have suggested the
necessity of their adoption. Kant has himself
acknowledged that his whole theory of the per¬
cipient and intellectual faculty was intended to
protect the first principles of human knowledge
against the assaults of Hume. In like manner,
his ethical system is evidently framed for the
purpose of guarding certain principles, either
directly governing, or powerfully affecting prac¬
tice, which seemed to him to have been placed
on unsafe foundations by their advocates, and
which were involved in perplexity and con¬
fusion, especially by those who adapted the re¬
sults of various and sometimes contradictory
systems to the taste of multitudes, more eager
to know than prepared to be taught. To the
theoretical reason he superadded the practical
reason, which had peculiar laws and prin¬
ciples of its own, from which all the rules of
morals may be deduced. The practical reason
cannot be conceived without these laws; there¬
fore they are inherent. It perceives them to he
necessary and universal. Hence, by a process
not altogether dissimilar, at least in its gross re¬
sults, to that which was employed for the like
purpose by Cudworth and Clarke, by Price, and
in some degree by Stewart, he raises the social
affections, and still more the moral sentiments,
above the sphere of enjoyment, and beyond that
series of enjoyments which is called happiness.
The performance of duty, not the pursuit of
happiness, is in this system the chief end of man.
By the same intuition we discover that virtue
deserves happiness; and as this desert is not
uniformly so requited in the present state of
existence, it compels us to believe a moral go¬
vernment of the world, and a future state of ex¬
istence, in which all the conditions of the prac¬
tical reason will be realized;-—truths, of which,
in the opinion of Kant, the argumentative proofs
were at least very defective, but of which the
revelations of the practical reason afforded a
more conclusive demonstration than any process
of reasoning could supply. The understanding,
he owned, saw nothing in the connection of mo¬
tive with volition different from what it discover¬
ed in every other uniform sequence of a cause
and an effect. But as the moral law delivered
by the practical reason issues peremptory and
DISSERTATION SECOND.
429
inflexible commands, the power of always obey¬
ing them is implied in their very nature. All in¬
dividual objects, all outward things, must indeed
be viewed in the relation of cause and effect.
They are necessary conditions of all reasoning.
But the acts of the faculty which wills^ of which
we are immediately conscious, belong to another
province of mind, and are not subject to these
laws of the theoretical reason. The mere intellect
must still regard them as necessarily connected;
but the practical reason distinguishes its own
liberty from the necessity of nature, conceives
volition without at the same time conceiving
an antecedent to it, and regards all moral beings
as the original authors of their own actions.
Even those who are unacquainted with this
complicated and comprehensive system, will at
once see the slightness of the above sketch.
Those who understand it, will own that so brief
an outline could not be otherwise than slight.
It will, however, he sufficient for the present
purpose, if it render what follows intelligible.
With respect to what is called the practical
reason, the Kantian system varies from ours, in
treating it as having more resemblance to the
intellectual powers than to sentiment and emo¬
tion. Enough has already been said on that
question. At the next step, however, the dif¬
ference seems to resolve itself into a misunder¬
standing. The character and dignity of the
human race surely depend, not on the state in
which they are horn, but on that which they are
all destined to attain or to approach. No man
would hesitate in assenting to this observation,
when applied to the intellectual faculties. Thus,
the human infant comes into the world imbecile
and ignorant; hut a vast majority acquire some
vigour of reason and extent of knowledge.
Strictly, the human infant is horn neither self¬
ish nor social; hut the far greater part acquire
some provident regard to their own welfare, and
a number, probably not much smaller, feel some
sparks of affection towards others. On our
principles, therefore, as much as on those of
Kant, human nature is capable of disinterested
sentiments. For we too allow and contend that
our moral faculty is a necessary part of human
nature,—that it universally exists in human
beings,—that we cannot conceive any moral
agents without qualities which are either like,
or produce the like effects. It is necessarily re¬
garded by us as co-extensive with human, and
even with moral nature. In what other sense
can universality he predicated of any proposition
not identical ? Why should it be tacitly assumed
that all these great characteristics of conscience
should necessarily presuppose its being unformed
and underived? What contradiction is there
between them and the theory of regular and
uniform formation ?
In this instance it should seem that a general
assent to truth is chiefly if not solely obstructed
by an inveterate prejudice, arising from the
mode in which the questions relating to the af¬
fections and the moral faculty have been dis¬
cussed among ethical philosophers. Generally
speaking, those who contend that these parts of
the mind are acquired, have also held that they
are, in their perfect state, no more than modi¬
fications of self-love. On the other hand, philo¬
sophers “ of purer fire,” who felt that conscience
is sovereign, and that affection is disinterested,
have too hastily fancied that their ground was
untenable, without contending that these quali¬
ties were inherent or innate, and absolutely un¬
derived from any other properties of mind. If a
choice were necessary between these two systems
as masses of opinion, without any freedom of dis¬
crimination and selection, I should unquestion¬
ably embrace that doctrine which places in the
clearest light the reality of benevolence and the
authority of the moral faculty. But it is surely
easy to apply a test which may he applied to our
conceptions as effectually as a decisive experiment
is applied to material substances. Does not he
who, whatever he may think of the origin of
these parts of human nature, believes that actually
conscience is supreme, and affection terminates
in its direct object, retain all that for which the
partisans of the underived principles value and
cling to their system ? “ But they are made,”
these philosophers may say, “ by this class of
our antagonists, to rest on insecure foundations.
Unless they are underived, we can see no reason
for regarding them as independent.” In answer,
it may be asked, bow is the connection between
these two qualities established ? It is really as¬
sumed. It finds its way easily into the mind
430
PRELIMINARY DISSERTATIONS.
under the protection of another coincidence,
which is of a totally different nature. The great
majority of those speculators who have repre¬
sented the moral and social feelings as acquired,
have also considered them as being mere modi¬
fications of self-love, and sometimes as being
casually formed and easily eradicated, like local
and temporary prejudices. But when the na¬
ture of our feelings is thoroughly explored, is it
not evident that this coincidence is the result of
superficial confusion ? The better moralists ob¬
served accurately, and reasoned justly, on the
province of the moral sense and the feelings in
the formed and mature man. They reasoned
mistakenly on the origin of these principles.
But the Epicureans were by no means right,
even on the latter question; and they were total¬
ly wrong on the other and far more momentous
part of the subject. Their error is more exten¬
sive, and infinitely more injurious. But what
should now hinder an inquirer after truth from
embracing but amending their doctrine where it
is partially true, and adopting without any change
the just description of the most important prin¬
ciples of human nature which we owe to their
more enlightened as well as more generous an¬
tagonists ?
Though unwilling to abandon the arguments
by which, from the earliest times, the existence
of the supreme and eternal mind has been esta¬
blished, avc, as well as the German philosophers,
are entitled to call in the help of our moral na¬
ture to lighten the burden of those tremendous
difficulties which cloud his moral government.
The moral nature is an actual part of man, as
much on our scheme as on theirs.
Even the celebrated question of Liberty and
Necessity may perhaps be rendered somewhat
less perplexing, if avc firmly bear in mind that
peculiar relation of conscience to will Avhich avc
have attempted to illustrate. It is impossible
for reason to consider occurrences otherAvise
than as bound together by the connection of
cause and effect; and in this circumstance con¬
sists the strength of the necessitarian system.
But conscience, which is equally a constituent
part of the mind, has other Iuavs. It is composed
of emotions and desires, which contemplate only
those dispositions which depend on the will. Now,
it is the nature of an emotion to withdraw the
mind from the contemplation of eA7ery idea but
that of the object which e>: :ites it. Every desire
exclusively looks at the object which it seeks.
EATery attempt to enlarge the mental vision al¬
ters the state of mind, weakens the emotion or
dissipates the desire, and tends to extinguish
both. If a man, while he was pleased with the
smell of a rose, were to reflect on the chemical
combinations from Avhich it arose, the condition
of his mind would be changed from an enjoy¬
ment of the senses to an exertion of the under¬
standing. If, in the ATiew of a beautiful scene,
a man were suddenly to turn his thoughts to
the disposition of Avater, vegetables, and earths,
on which its appearance depended, he might en¬
large his knoAvledge of geology, but he must
lose the pleasure of the prospect. The anatomy
and analysis of the flesh and blood of a beauti¬
ful Avoman necessarily suspend admiration and
affection. Many analogies here present them¬
selves. When life is in danger either in a storm
or a battle, it is certain that less fear is felt by
the commander or the pilot, and even by the
private soldier actively engaged, or the common
seaman laboriously occupied, than by those who
are exposed to the peril, but not employed in
the means of guarding against it. The reason is
not that the one class believe the danger to be
less. They are likely in many instances to per¬
ceive it more clearly. But having acquired a
habit of instantly turning their thoughts to the
means of counteracting the danger, their minds
are fhroAvn into a state AA7hich excludes the as¬
cendency of fear. Mental fortitude entirely
depends on this habit. The timid horseman is
haunted by the horrors of a fall. The bold and
skilful thinks only about the best way of curb¬
ing or supporting his horse. E\ren when all
means are equally unavailable, and his condition
appears desperate to the by-stander, he still owes
to his fortunate habit that he does not suffer
the agony of the coward. Many cases have
been known Avhere fortitude has reached such
strength that the faculties, instead of being con¬
founded by danger, are never raised to their
highest activity by a less violent stimulant. The
distinction between such men and the coward
does not depend on difference of opinion about
DISSERTATION SECOND.
431
the reality or extent of the clanger, hut on a
state of mind which renders it more or less ac¬
cessible to fear. Though it must be owned that
the moral sentiments are very different from any
other human faculty, yet the above observations
seem to be in a great measure applicable to every
state of mind. The emotions and desires which
compose conscience, while they occupy the mind,
must exclude all contemplation of the cause in
which the object of these feelings may have ori¬
ginated. To their eye the voluntary dispositions
and actions, their sole object, must appear to be
the first link of a chain. In the view of con¬
science they have no foreign original. The con¬
science being so constantly associated with all
volitions, its view becomes habitual:—being al¬
ways possessed of some, and capable of intense
warmth, it predominates over the habits of
thinking of those few who are employed in the
analyses of mental occupations. The reader
who has in any degree been inclined to adopt
the explanations attempted above, of the im¬
perative character of conscience, may be dis¬
posed also to believe that they afford some foun¬
dation for that conviction of the existence of
a power to obey its commands, which (it ought
to be granted to the German philosophers) is
irresistibly suggested by the commanding tone
of all its dictates. If such an explanation should
be thought worthy of consideration, it must be
very carefully distinguished from that illusive
sense by which some writers have laboured to
reconcile the feeling of liberty with the reality
of necessity.1 In this case there is no illusion;
—nothing is required but the admission, that
every faculty observes its own laws, and that
when the action of the one fills the mind, that
of every other is suspended. The ear cannot
see, nor can the eye hear. Why then should
not the greater powers of reason and conscience
have different habitual modes of contemplating
voluntary actions ? How strongly do experience
and analogy seem to require the arrangement of
motive and volition under the class of causes
and effects ! With what irresistible power, on
the other hand, do all our moral sentiments re¬
move extrinsic agency from view, and concen¬
trate all feeling in the agent himself! The
one manner of thinking may predominate among
the speculative few in their short moments of
abstraction; the other will be that of all other
men, and of the speculator himself when he is
called upon to act, or when his feelings are
powerfully excited by the amiable or odious
dispositions of his fellow-men. In these work¬
ings of various faculties there is nothing that
can be accurately described as contrariety of
opinion. An intellectual state, and a feeling,
never can be contrary to each other. They
are too utterly incapable of comparison to be
the subject of contrast. They are agents of a
perfectly different nature, acting in different
spheres. A feeling can no more be called
true or false, than a demonstration, considered
simply in itself, can be said to be agreeable or
disagreeable. It is true, indeed, that in conse¬
quence of the association of all mental acts with
each other, emotions and desires may occasion
habitual errors of judgment;—but liability to
error belongs to every exercise of human reason;
it arises from a multitude of causes; it con¬
stitutes, therefore, no difficulty peculiar to the
case before us. Neither truth nor falsehood can
be predicated of the perceptions of the senses,
but they lead to false opinions. An object seen
through different mediums may by the inex¬
perienced be thought to be no longer the same.
All men long concluded falsely, from what they
saw, that the earth was stationary, and the sun
in perpetual motion around it. The greater part
of mankind still adopt the same error. Newton
and Laplace used the same language with the
ignorant, and conformed (if we may not say to
their opinion) at least to their habits of thinking
on all ordinary occasions, and during the far
greater part of their lives. Nor is this all:
The language which represents various states of
mind is very vague. The word which denotes
a compound state is often taken from its princi¬
pal fact, from that which is most conspicuous,
most easily called to mind, most warmly felt, or
most frequently recurring. It is sometimes bor-
1 Loud Kames, in his Essays on Morality and Natural Religion, and in his Sketches of the History of Man.
432
PRELIMINARY DISSERTATIONS.
rowed from a separate, but, as it were, neigh¬
bouring condition of mind. The grand distinc¬
tion between thought and feeling is so little ob¬
served, that we are peculiarly liable to confusion
on this subject. Perhaps when we use language
which indicates an opinion concerning the acts
of the will, we may mean little more than to ex¬
press strongly and warmly the moral sentiments
which voluntary acts alone call up. It would
argue disrespect for the human understanding,
vainly employed for so many centuries in recon¬
ciling contradictory opinions, to propose such
suggestions without peculiar diffidence ; but be¬
fore they are altogether rejected, it may be well
to consider, whether the constant success of the
advocates of necessity on one ground, and of the
partisans of free-will on another, does not seem
to indicate that the two parties contemplate the
subject from different points of view, that nei¬
ther habitually sees more than one side of it, and
that they look at it through the medium of dif¬
ferent states of mind.
It should be remembered that these hints of a
possible reconciliation between seemingly re¬
pugnant opinions are proposed, not as perfect
analogies, but to lead men’s minds into the in¬
quiry, whether that which certainly befalls the
mind, in many cases on a small scale, may not,
under circumstances favourable to its develop¬
ment, occur with greater magnitude, and more
important consequences. The coward and brave,
as has been stated, act differently at the approach
of danger, because it produces exertion in the
one and fear in the other. But very brave men
must, by the terms, be few. They have little
aid in their highest acts, therefore, from fellow-
feeling. They are often too obscure for the
hope of praise, and they have seldom been train¬
ed to cultivate courage as a virtue. The very
reverse occurs in the different view taken by under¬
standing and by conscience^ of the nature of volun¬
tary actions. The conscientious view must, in
some degree, present itself to all mankind. It
is therefore unspeakably strengthened by gene¬
ral sympathy. All men respect themselves for
being habitually guided by it. It is the object of
general commendation : and moral discipline has
no other aim but its cultivation. Whoever does
not feel more pain from his crimes than from his
misfortunes, is looked on with general aversion.
And when it is considered that a Being of per¬
fect wisdom and goodness estimates us accord¬
ing to the degree in which conscience governs
our voluntary acts, it is surely no wonder that,
in this most important discrepancy between the
great faculties of our nature, we should con¬
sider the best habitual disposition to be that
which the coldest reason shows us to be most
conducive to welldoing and wellbeing.
On every other point, at least, it should seem
that, without the multiplied suppositions and
immense apparatus of the German School, the
authority of morality may be vindicated, the
disinterestedness of human nature asserted, the
first principles of knowledge secured, and the
hopes and consolations of mankind preserved.
Ages may yet be necessary to give to ethical
theory all the forms and language of science, and
to apply it to the multiplied and complicated facts
and rules which are within its province. In the
mean time, if any statement of the opinions here
unfolded or intimated shall be proved to be at
variance with the reality of social affections, and
with the feeling of moral distinction, the author
of this Dissertation will be the first to relinquish
a theory which will then show itself inadequate
to explain the most indisputable, as well as by
far the most important, parts of human nature.
If it shall be shown to lower the character of
man, to cloud his hopes, or to impair the sense
of duty, he will be grateful to those who may
point out his error, and deliver him from the
poignant regret of adopting opinions which lead
to consequences so pernicious.
NOTES AND ILLUSTRATIONS.
Kotes
and
Illustrations.
Note A, p. 321.
The remarks of Cicero on the Stoicism of Cato
are perhaps the most perfect specimen of that
refined raillery which attains the object of the
orator without general injustice to the person
whose authority is for the moment to he abated.
£C Accessit his doctrina non moderata, nec
mitis, sed, ut mihi videtur, paulo asperior et
durior quam aut veritas aut natura patiatur.”
After an enumeration of the Stoical paradoxes,
he adds: ct Hsec homo ingeniosissimus M. Cato
arripuit, neque disputandi causa, ut magna pars,
sed ita vivendi. Nostri autem illi (fatebor enim
me quoque in adolescentia diffisum ingenio meo
qusesisse adjumenta doctrinse) nostri, inquam, illi
a Platone atque Aristotele moderati homines et
temperati aiunt apud sapientem valere aliquando
gratiam; viri boni esse misereri; omnes
virtutes mediocritate quadam moderatas. Hos
ad magistros si qua te fortuna, Cato, cum ista na¬
tura detulisset, non tu quidem vir melior esses,
nec fortior, nec temperantior, nec justior (neque
enim esse posses), sed paulo ad lenitatem pro-
pensior.” (Giceuopro Murena.)
Note B, p. 325.
The greater part of the following extract from
Grotius’s History of the Netherlands is inserted
as the best abridgement of the ancient history of
these still subsisting controversies known in our
time. I extract also the introduction as a mo¬
del of the manner in which an historian may
state a religious dispute which has influenced
political affairs; but far more because it is an
unparalleled example of equity and forbearance
in the narrative of a contest of which the histo¬
rian was himself a victim.
“ Habuit hie annus (1608) baud spernendi
DISS. II.
quoque mali semina, vix ut arma desierant, ex- Notes
orto publicae religionis dissidio, latentibus initiis, . and
...... Illustrations.
sed ut paulatim in majus erumperet. Lugduni
sacras literas docehant viri eruditione prsestan-
tes Gomarus et Arminius, quorum ille seterna
Dei lege fixum memorabat, cui hominum salus
destinaretur, quis in exitium tenderet; inde
alios ad pietatem train, et tractos custodiri ne
elahantur; relinqui alios communi humanitatis
vitio et suis criminibus involutes: hie vero
contra integrum judicem, sed eundem optimum
patrem, id reorum fecisse discrimen, ut peccandi
pertsesis fiduciamque in Christum reponentibus
veniam ac vitam daret, contumacibus poenam ;
Deoque gratum, ut omnes resipiscant, ac meliora
edocti retineant; sed cogi neminem. Accusa-
bantque invicem; Arminius Gomarum, quod
peccandi causas Deo ascriberet, ac fati persua-
sione teneret immohiles animos; Gomarus Ar-
minium, quod longius ipsis Romanensium scitis
hominem arrogantia impleret, nec pateretur soli
Deo acceptam ferric rem maximam, bonam men-
tem. Constat his queis cura legere veterum
libros, antiques Christianorum tribuisse homi¬
num voluntati vim liberam, tarn in acceptanda,
quam in retinenda disciplina; unde sua praemiis
ac suppliciis sequitas. Neque iidem tamen
omisere cuncta divinam ad bonitatem referre,
cujus munere salutare semen ad nos pervenisset,
ac cujus singular! auxilio pericula nostra indi-
gerent. Primus omnium Augustinus, ex quo
ipsi cum Pelagio et eum secutis certamen (iiam
ante aliter et ipse senserat), acer disputandi, ita
libertatis vocem relinquere, ut ei decreta quaedam
Dei praeponeret, quae vim ipsam destruere vide-
rentur. At per Graeciam quidem Asiamque re-
tenta vetus ilia ac simplicior sententia. Per oc-
cidentem magnum Augustini nomen multos
traxit in consensum, repertis tamen per Galliam
et alibi qui se opponerent. Posterioribus saecu-
3 I
434
preliminary dissertations.
Notes lis, cum schola non alio magis quam Augnstino
strations ^octore uteretur, quis ipsi sensus, quis dexter
pugnare visa conciliandi modus, diu inter Fran-
cisci et Dominici familiam disputato, doctissimi
Jesuitarum, cum exactiori subtilitate nodum sol¬
vere laborassent, Rom re accusati regre damna-
tionem effugere. At Protestant! um princeps,
Luther us, egressus monasterio quod Augustini
ut nomen, ita sensus sequebatur, parte Augustini
arrepta, id quod is reliquerat, libertatis nomen,
ccepit exscindere; quod tarn grave Erasmo vi¬
sum, ut cum cretera ipsius aut probaret aut si-
lentio transmitteret, hie objiciat sese: cujus ar¬
guments motus Philippus Melanchthon, Lutheri
adjutor, quse prius scripserat immutavit, auctor-
que fuit Luthero, quod multi volunt, certe quod
constat Lutheranis, deserendi decreta rigida et
conditionem respuentia; sic tamen ut libertatis
vocabulum quam rem magis perhorrescerent. At
in altera Protestantium parte dux Calvinus,
primis Lutheri dictis in hac controversia inhre-
rescens, novis ea fulsit prresidiis, addiditque in-
tactum Augustino, veram ac salutarem jidem rem
esse perpetuam et amitti nesciam: cujus proinde
qui sibi essent conscii, eos seternre felicitatis jam
nunc certos esse, quos interim in crimina, quan-
tumvis gravia, prolabi posse non diffitebatur.
Auxit sententire rigorem Genevre Beza, per Ger-
maniam Zanchius, Ursinus, Piscator, srepe eo
usque provecti, ut, quod alii anxie vitaverant,
apertius nonnunquam traderent, etiam peccandi
necessitatem a prima causa pendere: quse ampla
Lutheranis criminandi materia.” (H. Grotii
Hist. lib. xvii. p. 552.)
Note C, p. 325.
The Calvinism, or rather Augustinianism, of
Aquinas, is placed beyond all doubt by the fol¬
lowing passages :—“ Prredestinatio est causa
gratire et glorise.” [Opera, VII. 356, edit. Paris.
1664.)
<£ Numerus prredestinatorum certus est.” [Ibid.
363.)
“ Prrescientia meritorum nullo modo est
causa prredestinationis divinre.” [Ibid. 370.)
<c Liberum arbitrium est facultas qua bonum
eligitur, gratia assistente, vel malum, eadem de-
sistente.” [Ibid. VIII. 222.)
“ Deus inclinat ad bonum administrando vir- Notes
tutem agendi et monendo ad bonum. Sed ad illustrations
malum dicitur inclinare in quantum gratiam
non prsebet, per quam aliquis a malo retrahere-
tur.” [Ibid. 364.)
On the other side:
“ Accipitur fides pro eo quo creditur, et est
virtus, et pro eo quod creditur, et non est virtus.
Fides qua creditur, si cum caritate sit, virtus est.”
[Ibid. IX. 236.)
“ Divina bonitas est primum principium com-
municationis totius quam Deus creaturis largi-
tur.”
ce Quamvis omne quod Deus vult justum sit,
non tamen ex hoc justum dicitur quod Deus illud
vult.” [Ibid. 697.)
Note D, p. 325.
The Augustinian doctrine is, with some hesi¬
tation and reluctance, acquiesced in by Scotus,
in that milder form which ascribes election to an
express decree, and considers the rest of mankind
as only left to the deserved penalties of their
transgressions. {S In hujus qusestionis solutione
mallemalios audire quamdocere.” (Scoti Opera,
V. 1329. Lugd. 1639.) This modesty and pru¬
dence is foreign from the dogmatical genius of a
Schoolman; and these qualities are still more ap¬
parent in the very remarkable language which
he applies to the tremendous doctrine of repro¬
bation. “ Eorum autem non miseretur (scil.
Deus) quibus gratiam non preebendam esse eequitate
occultissima et ab humanis sensibus remotissima ju-
dicatA [Ibid. 1329.) In the commentary on
Scotus which follows, it appears that his acute
disciple Ockham disputed very freely against the
opinions of his master. ££ Mala fieri bonum est”
is a startling paradox, quoted by Scotus from
Augustin. [Ibid. 1381.) It appears that Ock¬
ham saw no difference between election and re¬
probation, and considered those who embraced
only the former as at variance with themselves.
[Ibid. 1313.)
Scotus, at great length, contends that our
thoughts (consequently our opinions) are not
subject to the will. (VI. 1054—1056.) One step
more would have led him to acknowledge that
all erroneous judgment is involuntary,and there-
DISSERTATION SECOND.
435
Notes fore inculpable and unpunishable, however per-
*nd. nicious.
Illustrations. mo
His attempt to reconcile foreknowledge with
contingency (V. 1300-1327), is a remarkable
example of the power of human subtlety to keep
up the appearance of a struggle where it is im¬
possible to make one real effort.
But the most dangerous of all the deviations
of Scotus from the system of Aquinas is, that he
opened the way to the opinion that the dis¬
tinction of right and wrong depends on the mere
will of the Eternal Mind. The absolute power
of the Deity, according to him, extends to all
but contradictions. His regular power [prdi-
nata) is exercised conformably to an order es¬
tablished by himself; “ si placet voluntati,
sub qua libera est, recta est lex.” (Scot. V.
1368, et seq.)
Note E, p. 325.
AXXa tM7]v ■^uyjiv yi axouffav KaGuv pav ayvoovGav.
(Plat. Soph. edit. Bip. II. 224.)
Ilafl'cci' axovffiov afx,a6iav uvai. {Ibid. 227.)
Plato is quoted on this subject by Marcus
Aurelius, in a manner which shows, if there
had been any doubt, the meaning to be, that all
error is involuntary.
Hada -^vyri axoittia, (pridiv (TLharojv), Stsobtui cckriduag.
Every mind is unwillingly led from truth.
(Epict. lib. i. cap. xxviii.)
Augustin closes the long line of ancient tes¬
timony to the involuntary character of error :
“ Quis est qui velit decipi ? Fallere nolunt bo-
ni; falli autem nec boni volunt nec mali.”
(Aug. Serm. de Verbo.)
«
Note F, p. 326.
From a long, able, and instructive disserta¬
tion by the commentator on Scotus, it appears
that this immoral dogma was propounded in
terms more bold and startling by Ockham,
who openly affirmed, that “ moral evil was
only evil because it was prohibited.” “ Oc-
hamus, qui putat quod nihil posset esse malum
sine voluntate prohibitiva Dei, haneque volun-
tatem esse liberam; sic ut posset earn non
habere, et consequenter ut posset fieri quod nul¬
la prorsus essent mala.” (Scot. VII. p. 859.) Notes
But, says the commentator, “ Dico primo legem tl]us^adtionj
naturalem non consistere in jussione ulla quae
sit actus voluntatis Dei. Haec est communissima
theologorum sententia.” (Scot. VII. p. 858.)
And indeed the reason urged against Ockham
completely justifies this approach to unanimity.
“ For,” he asks, “ why is it right to obey the
will of God ? Is it because our moral faculties
perceive it to be right ? But they equally per¬
ceive and feel the authority of all the primary
principles of morality; and if this answer be
made, it is obvious that those who make it do in
effect admit the independence of moral distinc¬
tions on the will of God.”
“ If God,” said Ockham, “ had commanded
his creatures to hate himself, hatred of God
would have been praiseworthy.” (Domin. Soto
de Justitia et Jure, lib. ii. qusest. 3, “ Utrum pree-
cepta Decalogi sint dispensabiliaa book dedi¬
cated to Don Carlos, the son of Philip II.) Suarez,
the last scholastic philosopher, rejected the Ock-
hamical doctrine, but allowed will to be a part
of the foundation of morality. “ Voluntas Dei non
est tota ratio bonitatis aut malitise.” (Suarez
de Legibus, lib. ii. 66, p. 71. edit. Lond. 1679.)
As the great majority of the Schoolmen sup¬
ported their opinion of this subject by the con¬
sideration of eternal and immutable ideas of
right and wrong in the divine intellect, it was
natural that the Nominalists, of whom Ockham
was the founder, who rejected all general ideas,
should also have rejected those moral distinc¬
tions which were then supposed to originate in
such ideas. Gerson was a celebrated Nominal¬
ist ; and he was the more disposed to follow the
opinions of his master, because they agreed in
maintaining the independence of the State on
the Church, and the superiority of the Church
over the Pope.
Note G, p. 326.
It must be premised that Charitas among the
ancient divines corresponded with of the
Platonists, and with the of later philoso¬
phers, as comprehending the love of all that is
loveworthy in the Creator or his creatures. It
is the theological virtue of charity, and corre-
436
PRELIMINARY DISSERTATIONS.
Notes sponds with no term in use among modern mo-
istrations ra^sts- “Cum ohjectumamoris sit bonum, dupli-
citer potest aliquis tendere in bonum alicujus rei;
uno modo, quod bonum illiusvei cul alteTum TefcTcit^
sicut amat quis vinum in quantum dulcedinem
vini peroptat 5 et hie amor vocatur a quibusdam
amor concupiscentioe. Amor autem iste non ter-
minatur ad rem qua dicitur amari, sed rejlectitur
ad rem Mam cui optatur bonum Mius rei. Alio
modo amor fortior in bonum alicujus rei, ita quod
ad rem ipsam terminatur ; et hie est amor
benevolentise. Qua bonum nostrum in Deo per-
fectum est, sicut in causa universal! bonorum;
ideo bonum in ipso esse magis naturaliter complacet
quam in nobis ipsis : et ideo etiam amore ami-
citise naturaliter Deus ab homine plus seipso dili-
gitur.”
The above quotations from Aquinas will pro¬
bably be sufficient for those who are acquainted
with these questions, and they will certainly be
thought too large by those who are not. In the
next question he inquires, whether in the love of
God there can be any view to reward. He ap¬
pears to consider himself as bound by authority
to answer in the affirmative; and he employs
much ingenuity in reconciling a certain expecta¬
tion of reward with the disinterested character
ascribed by him to piety in common with all
the affections which terminate in other beings.
“ Nihil aliud est merces nostra quam perfrui Deo.
Ergo charitas non solum non excludit, sed etiam
facit habere oculum ad mercedem.” In this
answer he seems to have anticipated the re¬
presentations of Jeremy Taylor [Sermon on
Growth in Grace); of Lord Shaftesbury [Inquiry
concerning Virtue, book i. part iii. sect. 3); of
Mr T. Erskine [Freeness of the Gospel, Edinb.
1828); and more especially of Mr John Smith
[Discourses, Lond. 1660). No extracts could
convey a just conception of the observations
which follow, unless they were accompanied
by a longer examination of the technical lan¬
guage of the Schoolmen than would be war¬
ranted on this occasion. It is clear that he
distinguishes well the affection of piety from the
happy fruits, which, as he cautiously expresses
it, “ are in the nature of a reward,” just as the
consideration of the pleasures and advantages
of friendship may enter into the affection and
strengthen it, though they are not its objects, Notei
and never could inspire such a feeling. It seems iiiustratjonSt
to me also that he had a dimmer view of another
doctrine, by which we are taught, that though
our own happiness be not the end which we
pursue in loving others, yet it may be the iijial
cause of the insertion of disinterested affections
into the nature of man. “ Ponere mercedem
aliquam finem amoris ex parte amati, est contra
rationem amicitise. Sed ponere mercedem esse
finem amoris ex parte amantis, non tamen ulti-
mum, prout scilicet ipse amor est qusedam ope¬
ratic amantis, non est contra rationem amicitise.
Possum operationem amoris amare propter ali-
quid aliud, salva amicitia. Potest habeas chari-
tatem habere oculum ad mercedem, uti ponat beati-
tudinem creatam finem amoris, non autem finem
amati.” Upon the last words my interpretation
chiefly depends. The immediately preceding
sentence must be owned to have been founded
on a distinction between viewing the good fruits
of our own affections as enhancing their intrin¬
sic pleasures, and feeling love for another on
account of the advantage to be derived from
him; which last is inconceivable.
Note H, p. 326.
“ Potestas spiritualis et secularis utraque
deducitur a potestate divina; ideo in tantum
secularis est sub spirituali, in quantum est a
Deo supposita; scilicet, in his quae ad salutem
animae pertinent. In his autem quae ad bonum
civile spectant, est magis obediendum potestati
secular!; sicut illud Matthaei, ‘ Reddite quae
sunt Caesaris Caesari.’ ” What follows is more
doubtful. “ Nisi forte potestati spirituali etiam
potestas secularis conjungatur, ut in Papa, qui
utriusque potestatis apicem tenet.” (VIII. 435.)
Here, says the French editor, it may be doubt¬
ed whether Aquinas means the Pope’s temporal
power in his own dominions, or a secular autho¬
rity indirectly extending over all for the sake of
religion. My reasons for adopting the more ra¬
tional construction are shortly these:—1. The
text of Matthew is so plain an assertion of the
independence of both powers, that it would be
the height of extravagance to quote it as an au¬
thority for the dependence of the state. At
DISSERTATION SECOND.
437
Notes most it could only be represented as recon-
lustrations c^a^e with such a dependence in one case.
2. The word forte seems manifestly to refer
to the territorial sovereignty acquired by the
Popes. If they have a general power in secu¬
lar affairs, it must be because it is necessary to
their spiritual authority; and in that case to
call it fortuitous would be to ascribe to it an ad¬
junct destructive of its nature. 3. His former
reasoning on the same question seems to be de¬
cisive. The power of the Pope over bishops,
he says, is not founded merely in his supe¬
rior nature, but in their authority being alto¬
gether derived from his, as the proconsular
power from the imperial. Therefore he infers
that this case is not analogous to the relation
between the civil and spiritual power, which are
alike derived from God. 4. Had an Italian
monk of the twelfth century really intended to
affirm the Pope’s temporal authority, he proba¬
bly would have laid it down in terms more ex¬
plicit and more acceptable at Rome. Hesitation
and ambiguity are here indications of unbelief.
Mere veneration for the apostolical see might
present a more precise determination against it,
as it caused the quotation which follows, respect¬
ing the primacy of Peter. (AguiN. Opera, VIII.
434, 435.)
A mere abridgement of these very curious pas¬
sages might excite a suspicion that I had tinc¬
tured Aquinas unconsciously with a colour of
my own opinions. Extracts are very difficult,
from the scholastic method of stating objections
and answers, as well as from the mixture of
theological authorities with philosophical rea¬
sons.
Note I, p. 328.
The debates in the first assembly of the Council
of Trent (1546), between the Dominicans who
adhered to Aquinas, and the Franciscans who
followed Scotus on original sin, justification, and
grace, are to be found in Fra Paolo, Istoria del
Concilia Tridentino, lib. ii. They show how much
metaphysical controversy is hid in a theological
form, how many disputes of our times are of no
very ancient origin, and how strongly the whole
western church, through all the divisions into
which it has been separated, has manifested the Notes
same unwillingness to avow the Augustinian and.
® ... Illustrations.
system, and the same fear of contradicting it. To
his admirably clear and short statement of these
abstruse controversies, must be added that of
his accomplished opponent Cardinal Pallavicino
(lib. vii. and viii.), who shows still moi'e evidently
the strength of the Augustinian party, and the
disposition of the Council to tolerate opinions
almost Lutheran, if not accompanied by revolt
from the Church. A little more compromising
disposition in the Reformers might have be¬
trayed reason to a prolonged thraldom. We
must esteem Erasmus and Melanchthon, but we
should reserve our gratitude for Luther and
Calvin. The Scotists maintained their doctrine
of merit of congruity, waived by the Council,
and soon after condemned by the Church of
England; by which they meant that they who
had good dispositions always received the divine
grace, not indeed as a reward of which they
were worthy, but as aid which they were fit and
willing to receive. The Franciscans denied
that belief was in the power of man. “ I Fran-
cescani lo negavano seguendo Scoto, qual vuole
die siccome dalle dimostrazioni per necessita
nasce la scienza, cosi dalle persuasioni nasca la
fede; e ch’essa 6 nelP intelletto, il quale e agente
naturale, e mosso naturalmente dall’oggetto. Al-
legavano Pesperienza, che nessuno pub credere
che vuole, ma quello che gli par vero.” (Fra
Paolo, Istoria del Concilia Trideniino, I. 193.
edit. Helmstadt, 1763, 4to.)
Cardinal Sforza Pallavicino, a learned and
very able Jesuit, was appointed, according to
his own account, in 1651, many years after the
death of Fra Paolo, to write a true history of
the Council of Trent, as a corrective of the
misrepresentations of the celebrated Venetian.
Algernon Sidney, who knew this court historian
at Rome, and who may be believed when he
speaks well of a Jesuit and a Cardinal, com¬
mends the work in a letter to his father, Lord
Leicester. At the end of Pallavicino’s work is
a list of three hundred and sixty errors in mat¬
ters of fact, which the Papal party pretend to
have detected in the independent historian, whom
they charge with heresy or infidelity, and, in
either case, with hypocrisy.
438
PRELIMINARY DISSERTATIONS.
Notes Note K, p. 330.
and
Illustrations.
<< Hoc tempore, Ferdinando et Isabella regnan-
tibus, in academia Salmantina jacta sunt ro-
bustioris theologise semina; ingentis enim famse
vir Franciscos de Victoria, non tam lucubrati-
onibus editis, quamvis hsec non magnse molis at
magni pretii sint, sed doctissimorum theologo-
rum educatione, quamdiu faerit sacrae scientiae
honos inter mortales, vehementer laudabitur.”
(Antonii Bibl. Hisp. Nova, Praef. iv. Madrid,
1783.) ‘4 Si ad morum instructores respicias,
Sotus iterum nominabitur.” [Ibid.)
Note L, p. 330.
The title of the published account of the con¬
ference at Valladolid is, <£ The controversy be¬
tween the Bishop of Chiapa and Dr Sepulveda;
in which the Doctor contended that the con¬
quest of the Indies from the natives was lawful,
and the Bishop maintained that it was unlaw¬
ful, tyrannical, and unjust, in the presence of
many theologians, lawyers, and other learned
men assembled by his Majesty.” (Antonii
Bibl. Hisp. Nova, tom. i. p. 192.)
Las Casas died in 1566, in the 92d year of
his age; Sepulveda died in 1571, in his 82d
year.
Sepulveda was the scholar of Pomponatius,
and a friend of Erasmus, Cardinal Pole, Aldus
Manutius, &c. In his hook De Justis Belli
Causis contra Indos suscepti, he contended only
that the king might justly {C ad ditionem Indos,
non herilem sed regiam et civilem, lege belli re-
digere.” (Antonies in voce Sepulveda: Bibl.
Hisp. Nova, tom. i. p. 703.)
But this smooth and specious language covered
a poison. Had it entirely prevailed, the cruel
consequence of the defeat of the advocate of
the oppressed would alone have remained; the
limitations and softenings employed by their
opponent to obtain success would have been
speedily disregarded and forgotten.
Covarruvias, another eminent Jurist, was sent
by Philip II. to the Council of Trent, at its re¬
newal in 1560, and, with Cardinal Buoncam-
pagni, drew up the decrees of reformation.
Francis Sanchez, the father of philosophical
grammar, published his Minerva at Salamanca Notes
in 1587 ; so active was the cultivation of philo- niug^miu
sophy in Spain in the age of Cervantes.
Note M, p. 343.
<c Alors en repassant dans mon esprit les di-
verses opinions qui m’avoient tour-a-tour en-
traine depuis ma naissance, je vis que bien
qu’aucune d’elles ne fut assez evidente pour pro-
duire immediatement la conviction, elles avoient
divers degres de vraisemhlance, et que Tassenti-
ment interieur s’y pretoit ou s’y refusoit a diffe-
rentes mesures. Sur cette premiere observation,
comparant entr’ elles toutes ces differentes idees
dans le silence des prejuges, je trouvai que la
premiere, et la plus commune, etoit aussi la plus
simple et la plus raisonnable; et qu’il ne lui
man quoit, pour reunir tous les suffrages, que
d’avoir ete proposee la derniere. Imaginez tous
vos philosophes anciens et modernes, ayant d’a™
bord epuise leur bizarres systemes de forces, de
chances, de fatalite, de necessite, d’atomes, de
monde anime, de matiere vivante, de materia-
lisme de toute espece; et apres eux tous Pillustre
Clarke, eclairant le monde, annoncant enfinl’Etre
des etres, et le dispensateur des choses. Avec
quelle universelle admiration, avec quel applau-
dissement unanime n’eut point ete recu ce nou¬
veau systeme si grand, si consolant, si sublime,
si propre a clever Tame, a donner une base a la
vertu, et en meme terns si frappant, si lumineux,
si simple, et, ce me semhle, offrant moins de
choses incomprehensibles al’esprit humain, qu’il
n’en trouve d’absurdes en tout autre systeme!
Je me disois, les objections insolubles sont com¬
munes a tous, pareeque I’esprit de 1’homme est
trop borne pour les resoudre: elles ne prouvent
done rien contre aucun par preference, mais
quelle difference entre les preuves directes.”—
{Emile, tome III. livre iv. p. 25.)
Note N, p. 353.
44 Est autemjMs quaedam potentia moralis, et
obligatio necessitas moralis. Moralem autem
intelligo, quae apud virum bonum aequipollet
naturali: Nam ut praeclare jurisconsultus Ro-
manus ait, quoe contra bonos mores sunt, ea nec
DISSERTATION SECOND.
439
Notes facere nos posse credendwn est. Vir bonus autem
Illustrations. est> <lui amat omnes, quantum ratio permittit.
Justitiam igitur, quae virtus est hujus affect us
rectrix, qaem <I>/Aav^wr;ay Grseci vocant, commo-
dissime, ni fallor, definiemus caritatem sapientis,
hoc est, sequentem sapientiae dictata. Itaque,
quod Carneades dixisse fertur, justitiam esse
summam stultitiam, quiaalienis utilitatibus con-
suli jubeat, neglectis propriis, ex ignorata ejus
definitione natum est. Caritas est benevolentia
universalis, et benevolentia amandi sive diligendi
habitus. Amare autem sive diligere est felici¬
tate alterius delectari, vel, quod eodem redit, fe-
licitatem alienam adsciscere in suam. Unde
difficilis nodus solvitur, magni etiam in Theolo-
gia momenti, quomodo amor non mercenarius
detur, qui sit a spe metuque et omni utilitatis
respectu separatus: scilicet, quorum utilitas de-
lectat, eorum felicitas nostrum ingreditur, nam
quse delectant, per se expetuntur. Et uti pul-
chrorum contemplatio ipsa jucunda est, pictaque
tabula Haphaelis intelligentem afficit, etsi nullos
census ferat, adeo ut in oculis deliciisque feratur,
quodam simulacro amoris; ita quumres pulchra
simul etiam felicitatis est capax, transit affect us
in verum amorem. Superat autem divinus amor
alios amores, quos Deus cum maximo successu
amare potest, quando Deo simul et felicius nihil
est, et nihil pulchrius felicitateque dignius intel-
ligi potest. Et quum idem sit potentiee sapien-
tiseque summae, felicitas ejus non tantum ingre¬
ditur nostrum (si sapimus, id est, ipsum ama-
mus), sed et facit. Quia autem sapientia carita¬
tem dirigere debet, hujus quoque definitione
opus erit. Arbitror autem notion! hominum op¬
time satisfieri, si sapientiam nihil aliud esse
dicamus, quam ipsam scientiam felicitatis.”
(Leibnitii Opera, tom. IV. pars iii. p. 294.)
“ Et jus quidem merum sive strictum nascitur
ex principio servandae pacis ; aequitas sive caritas
ad majus aliquid contendit, ut, dum quisque
alter! prodest quantum potest, felicitatem suam
augeat in alien a; et, ut verbo dicam, jus stric¬
tum miseriam vitat, jus superius ad felicitatem
tendit, sed qualis in banc mortalitatem cadit.
Quod vero ipsam vitam, et quicquid hanc vitam
expetendam facit, magno commodo alieno post-
habere debeamus, ita ut maximos etiam dolores in
aliorum gratiam perferre oporteat; magis pulchre
praecipitur a philosophis quam solide demonstra- Notes
tur. Nam decus et gloriam, et animi sui virtute j]]ust"ations
gaudentis sensum, ad quae sub honestatis nomine
provocant, cogitationis sive mentis bona esse
constat, magna quidem, sed non omnibus nec
omni malorum acerbitati praevalitura, quando non
omnes aeque imaginando afficiuntur; praesertim
quos neque educatio liberalis, neque consuetudo
vivendi ingenua, vel vitae sectaeve disciplina ad
honoris aestimationem, vel animi bona sentienda
assuefecit. Ut vero universal! demonstratione
conficiatur, omne honestum esse utile, et omne
turpe damnosum, assumenda est immortalitas
animae, et rector universi Deus. Ita fit, ut omnes
in civitate perfectissima vivere intelligamur, sub
monarcha, qui nec ob sapientiam falli, nec ob
potentiam vitari potest; idemque tarn amabilis
est, ut felicitas sit tali domino servire. Huic
igitur qui animam impendit, Christo docente, earn
lucratur. Hujus potentia providentiaque effici-
tur, ut omne jus in factum transeat, ut nemo
laedatur nisi a se ipso, ut nihil recte gestum sine
prsemio sit, nullum peccatum sine poena.” [Ibid.
p. 296.)
Note O, p. 356.
The writer of this Discourse was led, on a
former occasion, by a generally prevalent no¬
tion, too nearly to confound the theological doc¬
trine of predestination with the philosophical
opinion which supposed the determination of
the will to be, like other events, produced by
adequate causes. (See a criticism on Mr Stewart’s
Dissertation, Edinb. Review, XXXVI. 255.)
More careful reflection has corrected a confusion
common to him with most writers on the sub¬
ject. What is called Sublapsarian Calvinism,
which was the doctrine of the most eminent
men, including Augustin and Calvin himself,
* ascribed to God, and to man before the fall, what
is called free-will, which they even own still to
exist in all the ordinary acts of life, though it
be lost with respect to religious morality. The
•decree of election, on this scheme, arises from
God’s foreknowledge that man was to fall, and
that all men became thereby with justice liable
to eternal punishment. The election of some to
salvation was an act of divine goodness, and the
PRELIMINARY DISSERTATIONS.
preterition of the rest was an exercise of holiness
and justice.
This sublapsarian predestination is evidently
irreconcilable with the doctrine of necessity,
which considers free-will, or volitions not caused
by motives, as absolutely inconsistent with the
definition of an intelligent being, which is, that
he acts from a motive, or, in other words, with
a purpose.
The supralapsarian scheme, which represents
the fall itself as fore-ordained, may indeed be
built on necessitarian principles. But on that
scheme original sin seems wholly to lose that
importance which the former system gives it as
a revolution in the state of the world, requiring
an interposition of divine power to remedy a
part of its fatal effects. It becomes no more
than the first link in the chain of predestined
offences. Yet both Catholic and Protestant
predestinarians have borrowed the arguments
and distinctions of philosophical necessitarians.
One of the propositions of Jansenius, condemned
by the bull of Innocent X. in 1653, is, that “ to
merit or demerit in a state of lapsed nature, it
is not necessary that there should be in man a
liberty free from necessity; it is sufficient that
there be a liberty free from constraint.” (Dupin,
Histoire de VEglise en abrege, siecle xvii. livre iv.
chap.viii. p. 193.) Luther, in his once famous
treatise de Servo Arbitrio against Erasmus (print¬
ed in 1526), expresses himself as follows : “ Hie
est fidei summus gradus, credere ilium esse cle-
mentem qui tam paucos salvat, tam multos dam-
nat; credere justum qui sua voluntate nos ne~
cessario damnabiles facit, ut videatur, ut Eras¬
mus refert, delectari cruciatibus miserorum, et
odio potius quam amore dignus.” My copy of
this stern and abusive book is not paged. In
another passage, he states the distinction be¬
tween co-action and necessity as familiar a hun¬
dred and thirty years before it was proposed by
Hobbes, or condemned in the Jansenists. “ Ne-
cessario dico,non coacte, sed, ut illi dicunt, neces¬
sitate immiftahilitatis, non coactionis; hoc est,
homo, cum vocat Spiritus Dei, non quidem vio-
lentia, velut raptus obtorto collo, nolens facit ma¬
lum, quemadmodum fur aut latro nolens ad poe-
nam ducitur, sed sponte et libera voluntate
facit.” He uses also the illustration of Hobbes,
from the difference between a stream forced Notes
out of its course and freely flowing in its chan- i1Ius^tiot s
Note P, p. 368.
Though some parts of the substance of the
following letter have already appeared in various
forms, perhaps the account of Mr Hume’s ill¬
ness, in the words of his friend and physician
Dr Cullen, will be acceptable to many readers.
I owe it to the kindness of Mrs Baillie, who had
the goodness to copy it from the original, in the
collection of her late learned and excellent hus¬
band, Dr Baillie. Some portion of what has
been formerly published I do not think it ne¬
cessary to reprint.
From Dr Cullen to Dr Hunter.
“ My Dear Friend,—I was favoured with
yours by Mr Halket on Sunday, and have an¬
swered some part of it by a gentleman whom I
was otherwise obliged to write by; but as I was
not certain how soon that might come to your
hand, I did not answer your postscript; in do¬
ing which, if I can oblige you, a part of the me¬
rit must he that of the information being early,
and I therefore give it you as soon as I possibly
could. You desire an account of Mr Hume’s
last days, and I give it you with some pleasure;
for though I could not look upon him in his ill¬
ness without much concern, yet the tranquillity
and pleasantry which he constantly discovered
did even then give me satisfaction, and, now
that the curtain is dropped, allows me to indulge
the less allayed reflection. He was truly an ex¬
ample des grands hommes qui sont marts en
plaisantant. ...For many weeks before his death
he was very sensible of his gradual decay; and
his answer to inquiries after his health was, seve¬
ral times, that he was going as fast as his ene¬
mies could wish, and as easily as his friends
could desire. He was not, however, without a
frequent recurrence of pain and uneasiness ; hut
he passed most part of the day in his drawing¬
room, admitted the visits of his friends, and, with
his usual spirit, conversed with them upon lite¬
rature, politics, or whatever else was accidental¬
ly started. In conversation he seemed to be per-
DISSERTATION SECOND.
441
Notes fectly at ease, and to the last abounded with
and that pleasantry, and those curious and enter-
lllustrations. , . r ‘
taming anecdotes, which ever distinguished him.
This, however, I always considered rather as an
effort to he agreeable; and he at length acknow¬
ledged that it became too much for his strength.
For a few days before his death, he became more
averse to receive visits; speaking became more
and more difficult for him, and for twelve hours
before his death his speech failed altogether.
His senses and judgment did not fail till the last
hour of his life. He constantly discovered a
strong sensibility to the attention and care of his
friends; and, amidst great uneasiness and lan¬
guor, never betrayed any peevishness or impa¬
tience. This is a general account of his last
days; hut a particular fact or two may perhaps
convey to you a still better idea of them.
# * * # #
‘ About a fortnight before his death, he added
a codicil to his will, in which he fully discover¬
ed his attention to his friends, as well as his own
pleasantry. What little wine he himself drank
was generally port, a wine for which his friend the
poet [John Home] had ever declared the strongest
aversion. David bequeaths to his friend John one
bottle of port; and, upon condition of his drink¬
ing this even at two down-sittings, bestows upon
him twelve dozen of his best claret. He plea¬
santly adds, that this subject of wine was the
only one upon which they had ever differed. In
the codicil there are several other strokes of
raillery and pleasantry, highly expressive of the
cheerfulness which he then enjoyed. He even
turned his attention to some of the simple amuse¬
ments with which he had been formerly pleased.
In the neighbourhood of his brother’s house in
Berwickshire is a brook, by which the access in
time of floods is frequently interrupted. Mr
Hume bequeaths L.100 for building a bridge
over this brook, hut upon the express condition
that none of the stones for that purpose shall be
taken from a quarry in the neighbourhood,
which forms part of a romantic scene in which,
in his earlier days, Mr Hume took particular de¬
light. Otherwise the money to go to the poor
of the parish.
“ These are a few particulars which may per-
mss. ii.
haps appear trifling; hut to me no particulars
seem trifling that relate to so great a man. It
is perhaps from trifles that we can best distin¬
guish the tranquillity and cheerfulness of the
philosopher, at a time when the most part of
mankind are under disquiet, anxiety, and some¬
times even horror....! had gone so far when I
was called to the country; and I have returned
only so long before the post as to say, that I am
most affectionately yours,
Notes
and
Illustrations.
“ William Cullen.
“ Edinburgh, \7th September 1776.”
Note Q, p. 369.
Pyrrho was charged with carrying his scepti¬
cism so far as not to avoid a carriage if it was
driven against him. iEnesidemus, the most
famous of ancient sceptics, with great probabi¬
lity vindicates the more ancient doubter from
such lunacy, of which indeed his having lived to
the age of ninety seems sufficient to acquit him.
Aivi6ibrtimg 8s <f>r\(Si <pi\o6o<psiv fisv olutov Tiara rov rrig
Xo'yov, fjjTi fjjsvroi ys angcogarug sxatSra <ffgarruv. (Diog.
Laert. lib. ix. sect. 62.)
Brief and imperfect as our accounts of ancient
scepticism are, it does appear that their reason¬
ing on the subject of causation had some resem¬
blance to that of Mr Hume. Ava/fouc/ 8s ro amov
uds’ ro ainov rm v^og n s'n, rrgog yas ruj ainara s6n'
ra 8s vgog n srrmsirai fiovov vrra^ii 8s ov xat ro ainov oia
svmoiro av fLovov. [Ibid. ix. sect. QT.) It is perhaps
impossible to translate the important technical
expression ra rroog tv. It comprehends two or
more things as related to each other—both the
relative and correlative taken together as such.
Fire considered as having the power of burning
wood is ro ‘rgog n. The words of Laertius may
therefore be nearly rendered into the language
of modern philosophy as follows: “ Causation
they take away thus. A cause is so only in re¬
lation to an effect. What is relative is only con¬
ceived, but does not exist. Therefore cause is a
mere conception.”
The first attempt to prove the necessity of be¬
lief in a divine revelation, by demonstrating that
natural reason leads to universal scepticism,
was made by Algazel, a professor at Bagdad, in
3 K
442
PRELIMINARY DISSERTATIONS.
Notes the beginning of the twelfth century of our era;
T„ and. whose work entitled The Destruction of the
Philosopher is known to us only hy the answer
of Averroes, called Destruction of the Destruc¬
tion. He denied a necessary connection be¬
tween cause and effect; for of two separate
things, the affirmation of the existence of one
does not necessarily contain the affirmation of
the existence of the other; and the same may he
said of denial. It is curious enough that this
argument was more especially pointed against
those Arabian philosophers who, from the ne¬
cessary connection of causes and effects, reasoned
against the possibility of miracles; thus antici¬
pating one doctrine of Mr Hume, to impugn an¬
other. (Tenneman, Gesch. der Phil. VIII. 387.)
The same attempt was made by the learned
hut unphilosophical Huet, bishop of Avranches
(Qucestiones Alnetance, Caen, 1690, and Traite de
la Foiblesse de VEsprit Humain, Amsterdam,
1723). A similar motive urged Berkeley to his
attack on Fluxions. The attempt of Huet has
been lately renewed hy the Abbe Lamennais,
in his treatise on Religious Indifference ; a fine
writer, whose apparent reasonings amount to
little more than well-varied assertions, and well-
disguised assumptions of the points to he proved.
To build religion upon scepticism is the most
extravagant of all attempts; for it destroys the
proofs of a divine mission, and leaves no natural
means of distinguishing between revelation and
imposture. The Abbe Lamennais represents
authority as the sole ground of belief. Why ?
If any reason can he given, the proposition
must he false; if none, it is obviously a mere
groundless assertion.
Note R, p. 372.
Casanova, a Venetian doomed to solitary im¬
prisonment in the dungeons at Venice in 1755,
thus speaks of the only hooks which for a time
he was allowed to read. The title of the first
was La Cite Mystique de Sceur Marie de Jesus,
appellee d’Agrada.
<c J’y lus tout ce que peut enfanter I’imagina-
tion exaltee d’une vierge Espagnole extravagam-
ment devote, cloitree, melancholique, ayant des Notes
directeurs de conscience, ignorans, faux, et de- iiiusat^tj&nB
vots. Amoureuse et amie tres intime de la
Sainte Vierge, elle avait re9u ordre de Dieu
meme d’ecrire la vie de sa divine mere. Les in¬
structions necessaires lui avaient ete fournies par
le Saint Esprit. Elle commem^oit la vie de Marie,
non pas du jour de sanaissance, mais du moment
de son immaculee conception dans le sein de sa
mere Anne. Apres avoir narre en detail tout
ce que sa divine heroine fit les neuf mois qu’elle
a passe dans le sein maternel, elle nous apprend
qu’a 1’age de trois ans elle balayoit la maison,
aidee par neuf cents domestiques, tous anges,
commandes par leur propre Prince Michel. Ce
qui frappe dans ce livre est Tassurance que tout
est dit de bonne foi. Ce sent les visions d’un
esprit sublime, qui, sans aucune ombre d’orgueil,
ivre de Dieu, croit ne reveler que ce que 1’Esprit
Saint lui inspire.” (Memoires de Casanova, IV.
343. Leipsic, 1827.)
A week’s confinement to this volume produced
such an effect on the author, who, though an un¬
believer and a debauchee, was then enfeebled by
melancholy, bad air, and bad food, that his sleep
was haunted, and his waking hours disturbed by
its horrible visions. Many years after, passing
through Agrada in Old Castile, he charmed the
old priest of that village by speaking of the bio¬
grapher of the virgin. The priest showed him
all the spots which were consecrated by her pre¬
sence, and bitterly lamented that the Court of
Rome had refused to canonize her. It is the
natural reflection of the writer, that the book
was well qualified to turn a solitary prisoner
mad, or to make a man at large an atheist. It
ought not to be forgotten, that the inquisitors of
state at Venice, who proscribed this book, were
probably of the latter persuasion. It is a strik¬
ing instance of the infatuation of those who, in
their eagerness to rivet the bigotry of the igno¬
rant, use means which infallibly tend to spread
utter unbelief among the educated. The book
is a disgusting, but in its general outline seem¬
ingly faithful, picture of the dissolute manners
spread over the Continent of Europe in the
middle of the eighteenth century.
/
DISSERTATION SECOND.
443
Notes Note S, p. 374.
and
Illustrations.
“ The Treatise on the Law of War and Peace,
the Essay on Human Understanding, the Spirit
of Laws, and the Inquiry into the Causes of the
Wealth of Nations, are the works which have
most directly influenced the general opinion of
Europe during the two last centuries. They
are also the most conspicuous landmarks in the
progress of the sciences to which they relate.
It is remarkable that the defects of all these
great works are very similar. The leading no¬
tions of none of them can, in the strictest sense,
be said to be original, though Locke and Smith
in that respect surpass their illustrious rivals.
All of them employ great care in ascertaining
those laws which are immediately deduced from
experience, or directly applicable to practice;
but apply metaphysical and abstract principles
with considerable negligence. None pursues
the order of science, beginning with first ele¬
ments, and advancing to more and more com¬
plicated conclusions; though Locke is perhaps
less defective in method than the rest. All
admit digressions which, though often intrinsi¬
cally excellent, distract attention, and break the
chain of thought. None of them is happy in
the choice, or constant in the use, of technical
terms; and in none do we find much of that
rigorous precision which is the first beauty of
philosophical language. Grotius and Montes¬
quieu were imitators of Tacitus,—the first with
more gravity, the second with more vivacity;
but both were tempted to forsake the simple
diction of science, in pursuit of the poignant
brevity which that great historian has carried to
a vicious excess. Locke and Smith chose an
easy, clear, and free, but somewhat loose and
Arerbose style—more concise in Locke—more
elegant in Smith,—in both exempt from pedantry,
but not void of ambiguity and repetition. Per¬
haps all these apparent defects contributed in
some degree to the specific usefulness of these
great works; and, by rendering their contents
more accessible and acceptable to the majority
of readers, have more completely blended their
principles with the common opinions of mankind.”
(Edinburgh Review, vol. XXXVI. p. 244.)
Note T, p. 379. Notes
und
Illustrations.
Ae; 8 burug, wcTtis £v yga/ufiariiuj u> /xridsv v-ira^u
ivreXsyjicf, yiy&xmiwm' ovreg avfifiuivii eth rou vou. (AriST.
de Anima, lib. iii. cap. v. Opera, tom. II. p. 50.
Paris, 1689.)
A little before, in the same treatise, appears a
great part of the substance of the famous maxim,
Nil est in intellectu quod non prius fuit in sensn.
'Hfo tpavraGia. xivriaig rig cSoxo aval, xai oux am ai(rt)t]<ttwg
ytyvusQat. (Ibid. 47.)
In the tract on Memory and Reminiscence
we find his enumeration of the principles of as¬
sociation. A/o xat ro ap^rig Origsvofiiv, wr^avng am rou
vuv aXXou rmg, %ai u<p o/moiou tj tvuvnov, q rou Ovvsyyvg.
(Ibid. II. 86.) If the latter word be applied to
time as well as space, and considered as compre¬
hending causation, the enumeration will coincide
with that of Hume. The term is as signi¬
ficant as if it had been chosen by Hobbes. But
it is to be observed, that these principles are ap¬
plied only to explain memory.
Something has been said on the subject, and
something on the present writer, by Mr Cole¬
ridge, in his unfortunately unfinished work called
Biographia Literaria, chap, v., which seems to
justify, if not to require, a few remarks. That
learned gentleman seems to have been guilty of
an oversight in quoting as a distinct work the
Parva Naturalia, which is the collective name
given by the scholastic translators to those trea¬
tises of Aristotle which form the second volume
of Duval’s edition of his works, published at
Paris in 1639. I have already acknowledged
the striking resemblance of Mr Hume’s prin¬
ciples of association to those of Aristotle. In
answer, however, to a remark of Mr Coleridge,
I must add, that the manuscript of a part of
Aquinas which I bought many years ago (on the
faith of a bookseller’s catalogue) as being written
by Mr Hume, was not a copy of the Commentary
on the Parva Naturalia, but of Aquinas’s own
Secunda Secundce; and that, on examination, it
proves not to be the handwriting of Mr Hume,
and to contain nothing written by him. It is
certain that, in the passages immediately preced¬
ing the quotation, Aristotle explains recollection
as depending on a general law,—that the idea of
444
PRELIMINARY DISSERTATIONS.
Notes an object will remind us of the objects which
Illustrations immediately preceded or followed when origi-
nally perceived. But what Mr Coleridge has not
told us is, that the Stagyrite confines the appli¬
cation of this law exclusively to the phenomena of
recollection alone, without any glimpse of a more
general operation extending to all connections of
thought and feeling,—a wonderful proof, indeed,
even so limited, of the sagacity of the great phi¬
losopher, hut which for many ages continued
barren of further consequences. The illustra¬
tions of Aquinas throw light on the original doc¬
trine, and show that it was unenlarged in his
time. “ When we recollect Socrates, the thought
of Plato occurs ‘ as like him.’ When we re¬
member Hector, the thought of Achilles occurs
‘ as contrary.’ The idea of a father is followed
by that of a son c as near.’ ” (Agum. Opera, I.
pars ii. p. 62, et seq.) Those of Ludovicus
Vives, as quoted by Mr Coleridge, extend no
farther.
But if Mr Coleridge will compare the parts of
Hobbes on Human Nature which relate to this
subject, with those which explain general terms,
he will perceive that the philosopher of Malmes¬
bury builds on these two foundations a general
theory of the human understanding, of which
reasoning is only a particular case. In conse¬
quence of the assertion of Mr Coleridge, that
Hobbes was anticipated by Descartes in his ex¬
cellent and interesting discourse on Method, I
have twice reperused that work in quest of this
remarkable anticipation, though, as I thought,
well acquainted by my old studies with the writ¬
ings of that great philosopher. My labour has,
however, been vain. I have discovered no trace
of that or of any similar speculation. My edi¬
tion is in Latin by Elzevir, at Amsterdam, in
1650, the year of Descartes’s death. I am
obliged, therefore, to conjecture that Mr Cole¬
ridge, having mislaid his references, has, by
mistake, quoted the discourse on Method, instead
of another work; which would affect his in¬
ference from the priority of Descartes to Hobbes.
It is not to be denied, that the opinion of Aris¬
totle, repeated by so many commentators, may
have found its way into the mind of Hohbes,
and also of Hume; though neither might he
aware of its source, or even conscious that it Notes
was not originally his own. Yet the very ]llu“adt.ons
narrow view of association by Locke, his appa-
rently treating it as a noArelty, and the silence
of common books respecting it, afford a pre¬
sumption that the Peripatetic doctrine was so
little known, that it might have escaped the
notice of these philosophers, one of whom boast¬
ed that he was unread, and the other is not
liable to the suspicion of unacknowledged bor¬
rowing.
To Mr Coleridge, who distrusts his own power
of building a bridge by which his ideas may pass
into a mind so differently trained as mine, I
venture to suggest, with that sense of his genius
which no circumstance has hindered me from
seizing every fit occasion to manifest, that more
of my early years were employed in contempla¬
tions of an abstract nature, than of those of the
majority of his readers; that there are not, even
now, many of them less likely to be repelled from
doctrines by singularity or uncouthness; more
willing to allow that every system has caught an
advantageous glimpse of some side or corner of
the truth; more desirous of exhibiting this dis¬
persion of the fragments of wisdom by attempts
to translate the doctrine of one school into the
language of another;—who, when he cannot
discover a reason for an opinion, considers it as
important to discover the causes of its adoption
by the philosopher; believing, in the most un¬
favourable cases, that one of the most arduous
and useful researches of mental philosophy is to
explore the subtile illusions which enable great
minds to satisfy themselves by mere words, be¬
fore they deceive others by payment in the same
counterfeit coin. These habits, together with
the natural influence of my age and avocations,
lead me to suspect that in speculative philosophy
I am nearer to indifference than to an exclusive
spirit. I hope that it can neither be thought
presumptuous nor offensive in me to doubt,
whether the circumstance of its being found
difficult to convey a metaphysical doctrine to a
person who, at one part of his life, made such
studies his chief pursuit, may not imply either
error in the opinion, or defect in the mode of
communication.
DISSERTATION SECOND.
445
Notes Note V, p. 395.
and
Illustrations.
A very late writer, who seems to speak tor
Mr Bentham with authority, tells us that “ the
first time the phrase of 4 the principle of utility’
was brought decidedly into notice, was in the
4 Essays, hy David Hume,’ published about the
year 1742. In that work it is mentioned as the
name of a principle which might be made the
foundation of a system of morals, in opposition
to a system then in vogue, which was founded an
what was called the 4 moral sense' The ideas,
however, there attached to it, are vague, and de¬
fective in practical application.” (Westminster Re¬
view, No. xxi.) If these few sentences were scru¬
tinized with the severity and minuteness of Ben-
tham’s Fragment on Government, they would be
found to con tain almost as many misrememhrances
as assertions. Utility is not 44 mentioned,” but
fully discussed, in Mr Hume’s Discourse. It is sel¬
dom spoken of by 44 name.” Instead of charging
it with 44 vagueness,” it would be more just to ad¬
mire the precision which it combines with beau¬
ty. Instead of being 44 defective in practical ap¬
plication,” perhaps the desire of rendering it po¬
pular has crowded it with examples and illus¬
trations taken from life. To the assertion that
44 it was opposed to the moral sense,” no reply can
he needful but the following words extracted
from the Discourse itself: 44 I am apt to suspect
that reason and sentiment concur in almost all
moral determinations and conclusions. The
final sentence which pronounces characters and
actions amiable or odious, probably depends on some
internal sense or feeling, which nature has made
universal in the whole species.” (An Enquiry con¬
cerning the Principles of Morals, sect, i.) The
phrase 44 made universal,” which is here used
instead of the more obvious and common word
“ implanted,” shows the anxious and perfect
precision of language, by which a philosopher
avoids the needless decision of a controversy not Notes
at the moment before him. illustrations.
Note W, p. 396.
A writer of consummate ability, who has fail¬
ed in little but the respect due to the abilities
and character of his opponents, has given too
much countenance to the abuse and confusion of
language exemplified in the well-known verse of
Pope,
Modes of self-love the Passions we may call.
44 We know,” says he, 44 no universal proposi¬
tion respecting human nature which is true but
one—that men always act from self-interest.”
(Edinburgh Review, March 1829.) It is mani¬
fest from the sequel, that the writer is not the
dupe of the confusion ; but many of his readers
may be so. If, indeed, the word self-interest
could with propriety be used for the gratification
of every prevalent desire, he has clearly shown
that this change in the signification of terms
would be of no advantage to the doctrine which
he controverts. It would make as many sorts
of self-interest as there are appetites, and it is
irreconcilably at variance with the system of as¬
sociation embraced by Mr Mill. To the word
self-love Hartley properly assigns two signifi¬
cations: 1. Gross self-love, which consists in
the pursuit of the greatest pleasures, from all
those desires which look to individual gratifica¬
tion; or, 2. refined self-love, which seeks the
greatest pleasure which can arise from all the
desires of human nature,—the latter of which
is an invaluable, though inferior principle. The
admirable writer whose language has occasioned
this illustration, who at an early age has mastered
every species of composition, will doubtless hold
fast to simplicity, which survives all the fashions
of deviation from it, and which a man of a
genius so fertile has few temptations to forsake.
END OF THE SECOND DISSERTATION.
DISSERTATION THIRD:
EXHIBITING A GENERAL VIEW
OF THE
RISE, PROGRESS, AND CORRUPTIONS
OF
CHRISTIANITY.
BY THE
MOST REV. RICHARD WHATELY,
AUCHBISHOP OP DUBLIN.
DISSERTATION THIRD
$
INTRODUCTION.
K
A sketch, like the present, of the rise, progress,
and corruptions of Christianity, would be alto¬
gether defective without some notice of those re¬
ligious systems which it was designed to supplant
or to complete.
Not only will much light be thrown upon its
genuine character and excellence by a contrast
with their errors or deficiencies, but moreover, a
knowledge of these will often disclose to us the
sources of some of those corruptions which have
disfigured the simplicity of the Gospel.
The earliest history of mankind, by far, that we
possess, is that contained in the Book of Genesis.
It is extremely brief and scanty ; especially the
earliest portion of it. But it plainly represents
the first of the human race, when in the Garden
of Eden , as receiving direct communications from
God. We have no detailed account, however, of
the instruction they received; and even part of
what the history does record is but obscurely in¬
timated. For example, it is rather hinted than
expressly stated, that the use of language was im¬
parted to them by revelation. This, however, is
generally understood to be the meaning of the
Diss. in.
passage (Gen. ii. 20), in which it is said that God
brought unto Adam the beasts and birds, to see
what he would call them, and that Adam gave
them names.
But our first parents, or their children, must
have received direct from God a great deal of in¬
struction of which no particulars are related. For
besides being taught something of religious and
moral duty (Gen. ii. 16 ; iv. 7), it is evident that
they must have learned something of the arts of
life. The first generations of mankind were cer¬
tainly not left at all in the condition of mere
savages, subsisting on such wild fruits and ani¬
mals as they might chance to meet with. We
read concerning the first two sons of Adam, that
the one was occupied in tilling the ground, and
the other in keeping cattle.
And even independently of the Bible history,
we might draw the same conclusion from what is
matter of actual experience, and as it were before
our eyes at this day. For it appears that mere
savages, if left to themselves without any instruc¬
tion, never did, and never can, civilise themselves.
And, consequently, the first of the human race
that did acquire any degree of civilisation, since
450
PRELIMINARY DISSERTATIONS.
they could not have had instruction from other
men, must have had a superhuman instructor.
But for such an instructor, all mankind would
have been savages at this day. The mere fact that
civilised men do exist, is enough to prove, even to
a person who had never heard of the Bible, that,
at some time or other, men must have been taught
something by a superior Being: in other words,
that there must have been a revelation.
It has been indeed not unfrequently main¬
tained that savages can, and sometimes do, invent
for themselves, one by one, all the useful arts, and
thus raise themselves to a civilised state, with¬
out any assistance from men already civilised.
One may meet with tine descriptions—though al¬
together fanciful—of this supposed progress of
men towards civilisation. One man, it has been
conceived, wishing to save himself the trouble of
roaming through the woods in search of wild
fruits and roots, would bethink himself of col¬
lecting the seeds of these, and cultivating them
in a spot of ground cleared and broken up for the
purpose. And finding that he could thus raise
more than enough for himself, he might agree
with some of his neighbours to let them have a
part of the produce in exchange for some of the
game and fish they might have taken. Another
again, it has been imagined, would endeavour to
save himself the labour and uncertainty of hunt¬
ing, by catching some kind of wild animals alive,
and keeping them in an inclosure to breed, that
he might have a supply always at hand.
And again, another, it is supposed, might de¬
vote himself to the occupation of dressing skins
for clothing, or of building huts or canoes, or
making various kinds of tools; and might subsist
by exchanging these with his neighbours for food.
And by thus devoting his chief attention to some
one kind of manufacture, he would acquire in¬
creased skill in that, and would strike out useful
new inventions.
Thus these supposed savages having gradually
come to be divided into husbandmen, shepherds,
andartisans of various kinds, would begin to enjoy
the various advantages of a division of labour,
and would advance, step by step, in all the arts
of civilised life.
Now, all this description is likely to appear
plausible, at the first glance, to those wrho do not
inquire carefully, and reflect attentively. But, on
examination, it will be found to be contradicted
by all history, and to be quite inconsistent with
the real character of such beings as savages actu¬
ally are. In reality, such a process of inventions
and improvements as that just described, is what
never did, and never possibly can, take place in
any savage tribe left wholly to themselves.
All the nations of which we know anything,
that have risen from a savage to a civilised state,
appear to have had the advantage of the instruc¬
tion and example of civilised men living among
them. Every nation that has ever had any tradi¬
tion of a time when their ancestors were savages,
and of the first introduction of civilisation among
them, always represent some foreigner or some
Being from heaven as having first taught them
the arts of life.
Thus the ancient Greeks, we know, attributed
to Prometheus the introduction of the use of fire.
And agriculture and other arts were popularly-
supposed to have been first introduced into Greece
by Triptolemus and Cadmus, and others, strangers
from a distant country.
And the Peruvians have a like tradition con¬
cerning a person they call Manco Capac, whom
they represent as the offspring of the sun, and as
having taught useful arts to their ancestors.
On the other hand, there are a great number of
savage tribes, in various parts of the world, who
have had no regular intercourse with civilised
men, but who have been visited by several voya¬
gers, at different times, and in some instances at
very distant periods. And it appears from com¬
paring together the accounts of those voyagers,
that these tribes remain perfectly stationary ; not
making the smallest advance towards civilisa¬
tion.
For example, the people of the vast continent
of New Holland, and of the large island of Papua
(or New Guinea), who are among the rudest of
savages, appear to remain (in those parts not set¬
tled by Europeans), in exactly the same brutish
condition as when they were first discovered.
They roam about the forests in search of wild ani¬
mals. and of some few eatable roots, which they
laboriously dig up with sharpened sticks. But
though they are often half-starved, and though
they have to expend as much toil for three or four
INTRODUCTION TO THE THIRD DISSERTATION.
451
scanty meals as would suffice for breaking up and
planting a piece of ground that would supply them
for a year, it has never occurred to them to at¬
tempt cultivating these roots.
The inhabitants, again, of the islands of Anda¬
man, in the eastern ocean, appear to be in a more
degraded and wretched state than even the New
Hollanders.
And to add but one instance more, the New
Zealanders, in the interval of above one hundred
and twenty-five years between the first discovery
of their islands by Tasman, and the second dis¬
covery by Captain Cook, seem to have made no
advances whatever, but to have remained just in
the same condition. And yet they were in a far
less savage state than that of the New Hollanders,
being accustomed rudely to cultivate the ground,
and raise crops of sweet potatoes.
And such appears to be, from all accounts, the
condition of all savage, or nearly savage, tribes.
They seem never to invent anything, or to make
any effort to improve; so that what few arts
they do possess (and which, in general, are only
such as to enable them just to support life), must
be the remnant that they have retained from a
more civilised state, from which their ancestors
had degenerated.
When, indeed, men have arrived at a certain
stage in the advance towards civilisation (far short
of what exists in Europe), it is then possible for
them, if nothing occurs to keep them back, to ad¬
vance further and further towards a more civil¬
ised state.
And this it is that misleads some persons in
their notions respecting savages. For finding
that there is no one art which might not have
been invented by unassisted man, supposing him
to have a certain degree of civilisation to start
from, they hence conclude that unassisted man
might have invented all the arts, supposing him
left originally in a completely savage state.
But this is contradicted by all experience; which
shews that men, in the condition of the lowest
savages, never have made the first step towards
civilisation, without some assistance from without.
Human society may be compared to some com¬
bustible substances which will not take fire spon¬
taneously, but when once set on fire will burn with
continually increasing force. A community of
men requires, as it were, to be kindled, and re¬
quires no more.
What, perhaps, contributes most to the erro¬
neous views referred to above, is, that when one
tries to fancy himself in the situation of a savage,
it occurs to him that he would set his mind to
work to contrive means for bettering his condi¬
tion, and that he might perhaps hit upon such
and such useful inventions; and hence he may
be led to think it natural that savages should do
so, and that some tribes of them may have ad¬
vanced themselves, in the way above described,
without any external help. But nothing of the
kind appears to have ever really occurred; and
what leads some persons to fancy it, is, that they
themselves are not savages, but have some de¬
gree of mental cultivation, and some of the ha¬
bits of thought of civilised men; and, there¬
fore, they form to themselves an incorrect notion
of what a savage really is—just as a person who
possesses eyesight cannot understand correctly
the condition of one born blind.
But those who have seen a good deal of real
savages, have observed that they are not onlv
feeble in mental powers, but also sluggish in the
use of such powers as they have, except when
urged by pressing want. When not thus urged,
they pass their time either in perfect inactivity,
or else in dancing, or decorating their bodies with
paint, or with feathers and shells, or in various
childish sports. They are not only brutishly
stupid, but still more remarkable for childish
thoughtlessness and improvidence. So that it
never occurs to them to consider how they may
put themselves in a better condition a year or two
hence.
Now, such must have been the condition of all
mankind down to this day, if they had all been,
from the first, left without any instruction, and
in what is called a state of nature-—that is,
with the faculties man is born with, not at all
unfolded or exercised by education. For from
such a state, unassisted Man cannot, as all expe¬
rience shews, ever raise himself. And conse¬
quently, in that case, the whole world would have
been peopled with mere savages in the very low¬
est state of degradation. The very existence,
therefore, at this day, of civilised men, proves
that there must have been, at some time or other,
452
PRELIMINARY DISSERTATIONS.
some instruction given to Man in the arts of life,
by some Being superior to Man. For, since the
first beginnings of civilisation could not ha\e
come from any human instructor, they must
have come from one sw^erhuman.
It has been shewn, then, that the whole world
would now have been peopled with the very low¬
est savages, if men had never received any in¬
struction, and yet had been able to subsist at all.
But it is doubtful whether even this bare sub¬
sistence 'would have been possible. It is more
likely that the first generation would all have
perished for want of those few arts which even
savages possess, and which (as has been above re¬
marked) were probably not invented by savages,
but are remnants which they have retained from
a more civilised state. The knowledge, for in¬
stance, of wholesome and of poisonous roots and
fruits, the arts of making fish-hooks and nets,
bows and arrows, or darts, and snares for wild ani¬
mals, and of constructing rude huts and canoes,
and some other such simple arts, are possessed,
more or less, by all savages, and are necessary to
enable them to support their lives. And it is
doubtful whether men left completely in a state
of nature—that is wholly untaught—would not
all perish before they could invent them for
themselves..
For we should remember that Man, when left
in a state of nature, untaught, and with his ra¬
tional powers not unfolded, is far less fitted for
supporting and taking care of himself than the
brutes. They are much better provided both
with instincts, and with bodily organs for sup¬
plying their own wants. For example, those
animals that have occasion to dig, either for food
or to make burrows for shelter—such as the
swine, the hedgehog, the mole, and the rabbit,
have both an instinct for digging, and snouts or
paws far better adapted for that purpose than
man’s hands. Yet man is enabled to turn up
the ground much better than any brute; but then
this is by means of tools which man can be taught
to make and use, though brutes cannot. Again,
birds and bees have an instinct for building such
nests and habitations as answer their purpose as
well as the most commodious beds and houses
made by men; but Man has no instinct that
teaches him how to construct these. Brutes,
again, know by instinct their proper food, and
avoid what is unwholesome; but man has no
instinct for distinguishing the nightshade-berry
(with which children have been so often poison¬
ed), from wholesome fruits. And quadrupeds
swim by nature, because their swimming is the
same motion by which they advance when on
land; but a man, falling into deep water, is
drowned, unless he has learnt to swim.
It appears, then, very doubtful whether men
left wholly untaught, would be able to subsist at
all, even in the state of the lowest savages. But,
at any rate, it is plain they could never have
risen above that state. And, consequently, the
existence of civilisation at this day is a kind of
monument attesting the fact that some instruc¬
tion from above must, at some time or other,
have been supplied to mankind; And the most
probable conclusion is, that Man, when first cre¬
ated, or very shortly afterwards, was advanced
by the Creator Himself, to a state above that of a
mere savage.
Now this is exactly what is related in Scrip¬
ture. But it must be remembered that the proof
which has been just given of an original revela¬
tion to Man, is quite independent of the Bible
history; and, therefore, tends to confirm that his¬
tory. That Man could not have made himself,
is appealed to, as a proof of a divine Creator.
And that mankind could not, in the first instance,
have civilised themselves, is a proof exactly ot
the same kind, and equally strong, of a super¬
human Instructor.
And here the inquiry may perhaps be raised,
how it ever came about that various tribes of
men, from time to time, degenerated into the
savage state. We have no distinct records of the
progress of this degeneracy; nor, from the na¬
ture of the case, is it possible that we should. But,
no doubt, wars have always been the principal
cause of it. When men were continually harass¬
ed by a superior force of ferocious enemies, who
hunted them down like wild beasts, and burnt
their dwellings, and laid waste the country, they
would be driven to shelter themselves in forests,
and deserts, and mountains ; and would have no
opportunity of practising, or of teaching to their
children, most of the arts they might be acquaint¬
ed with. Agriculture, for instance, would neces-
INTRODUCTION TO THE THIRD DISSERTATION.
453
sarily be abandoned. And being entirely occu¬
pied in a struggle for bare subsistence, and in
providing for defence against their enemies, or
for escape, they would have neither leisure, nor
means, nor inclination, for keeping up the various
arts of civilised life. These, therefore^ would, in
two or three generations, be forgotten and irreco¬
verably lost among them; and the whole character
of the people would have degenerated.
We have said, that from the very nature of the
case, it is impossible we should have any distinct
accounts of the progress of this degradation, since
men so situated would not compose histories.
Rut it is remarkable that in several savage tribes,
there are some faint traditions of their ancestors
having formerly come from some distant and
better country; doubtless driven out by war.
It is likely that the instruction in the arts of
life that was originally bestowed on the human
race was merely sufficient to give them a begin¬
ning ; to advance them just so far towards civil¬
isation as to enable them, thenceforward, to ad¬
vance themselves, and to invent, one by one, by
the exercise of their own faculties, various arts,
according to their wants and opportunities.
The Bible history informs us of hardly any
particulars, either of what was originally taught
to mankind, or of their own inventions. We
have only a very brief and slight hint of the in¬
vention of the art of working metals, and of
musical instruments, and perhaps, also of tents.
(Gen. iv. 20.) But, doubtless, many other arts
were invented before the Flood.
Several of the most important arts, and of
those most generally known throughout the
world, must have been very ancient; and as their
first introduction is not mentioned in the Bible,
there is no record or tradition of it. And we
are so familiar with these that we are apt to re¬
gard them as more simple and obvious than they
are; though, on reflection, it will appear that
some of them were most likely invented gradu¬
ally, and by successive steps taken at long inter¬
vals.
And here it is worth observing how import¬
ant an advantage, in reference to the invention
of arts, would have been afforded to men in a
very early and rude state of society, by their pos¬
sessing (as Scripture informs us the earliest of
them did) a very long continuance of life. In the
present day, an ingenious and observant man
writes down, and generally prints and publishes
the experiments and observations he has made ;
and thus those who come after him are enabled
to follow up his inquiries and attempts, so that
each generation improves upon the last. But
before the use of printing and writing, the chief
part of each man’s experience would be lost to
those who came after him. In those early days,
therefore, it was of vast importance, with a view
to the invention of arts, that each man should
be enabled, by great length of life, to apply his
own experience, and to follow up himself the dis¬
coveries he might have made.
We have no direct information as to the imme¬
diate cause of the great longevity of the earliest
generations of men. But it seems likely that it
may have been produced by the influence of “ the
Tree of Life."1
That the produce of this tree (whether its
fruits or its leaves) was endued by the Creator
with some property of warding off death, we are
plainly taught, both by its name and by the ex¬
clusion of Adam from the Garden of Eden, “ lest
he should eat of the tree of life, and live for
ever.”
It is likely that it had the medicinal virtue,
when applied from time to time, of preventing or
curing the decays of old age; just as our ordinary
food preserves men from dying of exhaustion by
famine; and as several well-known medicines pre¬
vent or cure certain diseases. We know, indeed,
that there does not exist now any medicine that
has the virtue of keeping up or renewing youth¬
ful health or vigour. But such a medicine would
not be in itself at all more strange than many
things which we are familiar with, but whose
effects we cannot explain, and could never have
conjectured.
For example, that opium and some other drugs
1 It appears to be a vestige of an early tradition respecting the use of the Tree of Life, that Homer represents his gods as
Bupjmrting perpetual life and vigour by drinking nectar and eating Ambrosia, i. e. (immortality.)
454
PRELIMINARY DISSERTATIONS.
should produce sleep, and strong liquors a kind of
temporary madness, is what no one would ever
have thought of, if he had never heard of it, nor
seen the experiment tried, of swallowing those
substances. Nor, even if he were a skillul che¬
mist, would he be able, by analysing them, to con¬
jecture what their effects would be. If, then,
the Tree of Life were such a medicine as we have
supposed, a person who always continued the use
of it from time to time, would continue exempt
from decay and death.
But supposing some persons who had been in
the habit of using it (as our first parents doubtless
had, since there was nothing to prevent them)
should afterwards cease, to use it, their constitu¬
tion would probably have been so far fortified,
that though they would at length die, yet they
would live much longer than man’s natural term.
And they would even be likely to transmit to their
descendants such a constitution as would confer
on those also a great degree of longevity, which
would only wear out gradually in many successive
generations.
Now, it is remarkable that this exactly agrees
with what we do find recorded. If we look into
those parts of the Bible history which relate to
this subject, we shall find Man’s life in the ear¬
liest generations extending to eight or nine cen¬
turies, and upwards. And we shall find longe¬
vity gradually diminishing in each generation,
down to the times of Abraham, Isaac, and Jacob,
who lived rather less than two hundred years;
and again down to the time of Moses, who began
his mission, apparently in the full vigour of life, at
fourscore, and lived to one hundred and twenty.
Joshua, who succeeded him, lived one hundred
and ten years. And from thenceforward human
life appears -to have been brought down to about
its present limit.
The above seems to be the most clear, easy, and
natural interpretation of those parts of Scripture
we have been examining. There is not, however,
any such distinct revelation on the subject as to
authorise our pronouncing confidently that such
must be the right interpretation, and making
this an article of faith.
With respect to religious instruction, although,
as has been said, the Maker and Governor of all
things did certainly make Himself known to the
earliest generations of mankind, and accepted wor¬
ship from them; we are told very few particulars
of the revelations that were made. We find, in¬
deed, a prophecy made to Adam and Eve, just be¬
fore their expulsion from Paradise : that the seed
of the woman should bruise the serpent’s head.
But whether any explanation was given them, of
the reference this had to our Saviour’s triumph
over Satan and Death, we are not told. And it
is even a matter of doubt among the learned,
whether the sacrifices (Gen. iv. viii.) that were
offered up in the earliest times, and afterwards
by Noah, were of express divine appointment,
or were merely a mode of worship which men
devised of themselves, and which God thought
fit to approve and accept. And there is nothing
so distinctly said in Scripture on the subject, as
to authorise any one to decide confidently, one
way or the other. If it had been necessary that
we should have any certainty as to this point,
doubtless we should have had some plain decla¬
rations upon it.
Of Enoch we find it recorded, that he “ walked
with God,” that is, led a life of eminent holiness,
and was so far favoured, as to be withdrawn from
the earth without tasting of death. And he is
referred to, in the Epistle to the Hebrews, as an
example oifaith, inasmuch as “ without faith it
is impossible to please God.” But as to the sub¬
jects of his faith, the Apostle himself seems to
have had no distinct and particular knowledge,
except that he must have believed in the exist¬
ence and in the goodness of God,—“ For he
that cometh to God must believe that He is ; and
that He is a rewarder of them that diligently
seek Him.”
Of course what is meant in this passage by the
word “ God,” is—what we also understand by
it—the Creator of the world. We cannot doubt
that He must have made Himself known to the
earliest of mankind, as the Maker of themselves,
and of all things around them. And the account
given in Genesis, of the creation, and of some
other of the earliest events, is probably a tradi¬
tion of this most ancient revelation, and was very
likely committed to writing, long before the time
of Moses.
Some persons have imagined that we are bound
INTRODUCTION TO THE THIRD DISSERTATION.
455
to take our notions of Astronomy, and of all other
Physical Sciences, from the Bible. And accord¬
ingly, when astronomers discovered and proved
that the earth turns round on its axis, and that
the sun does not move round the earth, some cried
out against this as profane, because Scripture
speaks of the sun’s rising and setting. And this
probably led some astronomers to reject the Bible,
because they were taught that if they received
that as a divine revelation, they must disbelieve
truths which they had demonstrated.
So also, some have thought themselves bound
to believe, if they receive Scripture at all, that
the earth, and all the plants and animals that
ever existed on it, must have been created within
six days, of exactly the same length as our pre¬
sent days. And this, even before the sun, by
which we measure our days, is recorded to have
been created. Hence, the discoveries made by
geologists, which seem to prove that the earth
and various races of animals must have existed
a very long time before Man existed, have been
represented as completely inconsistent with any
belief in Scripture.
We may not stop to discuss the various objec¬
tions (some of them more or less plausible, and
others very weak), that have been brought—on
grounds of science, or supposed science—against
the Mosaic accounts of the creation, of the state
of the early world, and of the flood, and to bring
forward the several answers that have been given
to those objections. But it is important to lay
down the PRINCIPLE on which either the Bible
or any other writing or speech ought to be studied
and understood, viz., with a reference to the ob¬
ject proposed by the writer or speaker.
For example, if we bid any one proceed in a
straight line from one place to another, and to
take care to arrive before the sun goes down, he
will rightly and fully understand us, in reference
to the practical object which alone we had in
view. Now, we know that there cannot really
be a straight line on the surface of the earth ;
and that the sun does not really go down, only
our portion of the earth is turned away from it.
But whether the other party knows all this or not,
matters nothing to our present object; which
was not to teach him mathematics or astronomy,
but to make him conform to our directions, which
are equally intelligible to the learned and the un¬
learned.
Now, the object of the Scripture revelation is
to teach men, not astronomy or geology, or any
other physical science, but Religion. Its design
was to inform men, not in what manner the world
was made, but WHO made it; and to lead them
to worship Him, the Creator of the heavens and
the earth, insteadof worshippinghiscreatures, the
heavens and earth themselves, as gods ; which is
what the ancient heathen actually did.
Although, therefore, Scripture gives very scan¬
ty and imperfect information respecting the earth
and the heavenly bodies, and speaks of them in
the language and according to the notions of the
people of a rude age, still it fully effects the ob¬
ject for which it was given, when it teaches
that the heavens and the earth are not gods
to be worshipped, but that “ God created the
heavens and the earth” and that it is He who
made the various tribes of animals, and also
Man.
But as for astronomy and geology and other
sciences, men were left, when once sufficiently
civilised to be capable of improving themselves,
to make discoveries in them by the exercise of
their own faculties.
But whatever may have been the religious in¬
struction originally afforded to mankind, most of
them appear not to have made the proper use of
their advantages; but to have fallen, in very early
times, into idolatry and superstitions of various
kinds.
Whether false religion was introduced before
the flood, we are not expressly told ; but there is
every reason to think it must have been. For
we read that mankind had become excessively
wicked, and that this brought on them that ter¬
rible judgment. And all experience shews that
great moral depravity and gross religious corrup¬
tion accompany each other. Moral corruption
favours the introduction of corrupted and false
religious notions ; and a false religion, in turn,
favours immorality.
Moreover, there is a passage in Genesis (chap,
iv. 26), which, though it be but an obscure hint,
seems to relate to the first introduction of false
gods, in the times of Enos, grandson of Adam, and
456
PRELIMINARY DISSERTATIONS.
apparently about three or four centuries after the
creation. The passage is translated in the text of
our version, “ Then began men to call upon the
name of the Lord: nllY
(Gen. iv. 26.) But the translation in the margin is
“ Then began men to call themselves by the name
of the Lord.” And some learned men translate
it, “ Then began men to call the Lord by name.
The sense of the passage certainly cannot be
that divine worship was then introduced for the
first time ; which, we know, from the preceding
history (ch.iv. 3), was not the case. But it probably
means that, then, those who worshipped the true
God, began to apply to Him some distinct name
or title, such as Adonai or Jehovah, to distin¬
guish Him from the pretended gods worshipped
by others, and that they called themselves “ by
his name,” that is, described themselves as his
worshippers, to distinguish themselves from those
who served other gods. As long as one God only
was acknowledged in the world, there was no need
to apply to Him any distinguishing title. But
when the worship of other Beings was introduced,
it would be necessary for the true worshippers to
mark the distinction. It is probable, therefore,
that this was the time when such false worship
first became prevalent.
In later times, we know, false religions did
prevail very extensively, as indeed they still do,
among a large portion of mankind.
We shall next consider what wras the real cha¬
racter of the Pagan religions, and in what way it
Is likely they were introduced.
THE PAGAN
The worshippers of false gods, such as the
greater part of mankind formerly were, are usu¬
ally called Heathens or Pagans. The word
Heathen as well as the word Gentiles, which
had the same meaning, signified originally Na¬
tions. But since all, or nearly all, nations ex¬
cept the Jews (who called themselves the Lord’s
People) were worshippers of false gods, hence
the word “ Heathen”1 came to be used as it is
now. And the word “ Pagan” also, which ori¬
ginally signified a Villager, came to be used in
the same sense; because, in the early times of
Christianity, many of the inhabitants of retired
country villages retained their old superstitions,
after the inhabitants of the towns had been con¬
verted to the Gospel.
RELIGIONS.
There are some persons, who, though possess¬
ing a considerable knowledge of things connected
with Mythology, yet mistake altogether the real
character of the Pagan religions. They some¬
times imagine that all men, in every age and
country, had always designed to worship one Su¬
preme God, the maker of all things ;2 and that
the error of the Pagans consisted merely in the
false accounts they gave of Him, and in their
worshipping other inferior gods besides.
But this is altogether a mistake. Pew, if any,
of the ancient Pagans ever thought of worship¬
ping a Supreme Creator at all. Those who be¬
lieved, or suspected, that the world had been cie-
ated, never pretended that it was the work of any
of the gods they worshipped.3 Many held that the
1 This is the commonly received etymology, though some think it is derived from the German Heiden, inhabitant
“ heath” or wilderness.
3 See Pope’s Universal Prayer.
“ Father of all, in every age,
In every clime adored ;
By saint, by savage, and by sage,
Jehovah, Jove, or Lord.”
3 Sic ubi dispositam quisquis fuit ille Dcorum Congeriem secuit, sectamque in membra redegit, &c. kc.— Ovicl. Metam. 1.
DISSERTATION THIRD.
457
world was not created, but eternal; and others
maintained that though it had a beginning, it
was the production of what they called chance ;
that is, they fancied that the particles of matter
of which the world consists, moved about at ran¬
dom, and accidentally fell into the shape it now
bears.
These persons were what we should call Athe¬
ists. For by the word GOD, we understand an
Eternal Being, who made and who governs all
things. And if any one should deny that there
is any such Being, we should say that he was an
Atheist; even though he might believe that there
do exist Beings superior to man ;l such as the
Fairies and Genii in whom the uneducated in
many parts of Europe still believe.
Accordingly, the Apostle Paul (Eph. ii. 12)
expressly calls the ancient Pagans Atheists («&«/),
though he well knew that they worshipped cer¬
tain supposed superior Beings which they called
gods. But he says in the Epistle to the Romans,
that they “ worshipped the creature more than2
(*• e. instead of) the Creator.” And at Lystra
(Acts xiv. 15), when the people were going to do
sacrifice to him and Barnabas, mistaking them
for two of their gods, he told them to C! turn from
these vanities to serve the living God, who made
heaven and earth."
This is what is declared in the first sentence
of the Book of Genesis. And so far were the
ancient Pagans from believing that “ in the be¬
ginning God made the heavens and the earth,”
that, on the contrary, the heavens, and the earth,
and the sea, and many other natural objects, were
among the very gods they adored.
The heavens—that is the sky, the atmosphere
around us—they worshipped under the titles of
Zeus or Dis—of Jupiter or Jove—and (among
the Canaanites and Babylonians) of Baal, Bel, or
Belus.3 They worshipped the earth also under
the names of Demeter and Cybele ; called by
our Anglo-Saxon ancestors Hertha (whence our
words “ earth” and “ hearth”), and by them most
especially venerated.
The Pagans also worshipped the sea, under
the title of Neptune ; the sun, under that of Phoe¬
bus or Apollo; and the moon, under that of Diana.
These last they called the son and daughter of
Jove; meaning that the sun and moon were pro¬
duced by the heavens.
The Egyptians also worshipped the same kind
of gods, and, among others, the great river Nile,
on which the fertility of their country depends.
The plagues which the Lord sent on Egypt (Exod.
xii. 12) when he delivered the Israelites, seem to
have been partly designed to prove his superi¬
ority and dominion over these pretended gods, by
making them the very instruments of his judg¬
ments. Their river was turned into blood ; the
earth brought forth a plague of frogs ; the sky, or
atmosphere which they worshipped, sent forth
destructive hail and lightning; and the sun was
darkened. This was a useful lesson, both to the
Israelites and to the Egyptians themselves, as
many as w'ould learn from it.
The ancient Pagans seem to have supposed
that certain living spirits resided in, and ruled
over, the air, the sun, moon, earth, and sea. And
besides these, they also Avorshipped a number of
other supposed Beings who presided over the se¬
veral passions, and faculties, and actions of man.
Thus Minerva was the goddess of wisdom ; and
Mars the god of Avar : and they often used the
word Minerva to signify intelligence, and Mars
to signify valour. So Hermes (or Mercury) Avas
supposed to preside over traffic, and also over elo¬
quence. And thence it Avas that the Lystrans
“called Paul £ Mercurius,’ because he Avas the
chief speaker.” (Acts xiv. 12.)
None of the ancient Pagans considered any of
their gods as eternal. They generally supposed
them immortal—that is, exempt from death;
“ Now, suppose that any one in those ages had denied the existence of God and his angels, would not his impiety justly
ave deserved the appellation of Atheism, even though he had still allowed, by some odd capricious reasoning, that the
popular stories of elves and fairies were just and well-grounded. The difference, on the one hand, between such a person
and a genuine Theist, is infinitely greater than that on the other between him and one who absolutely excludes all invisible
intelligent power. And it is a fallacy merely from the casual resemblance of names, without any conformity of meaning,
to rank such opposite opinions under the same denomination. To any one who considers justly of the matter, it will appear
at the gods of all PoZytheists are no better than the elves or fairies of our ancestors, and merit as little any pious worship
or veneration. These pretended religionists are really a kind of superstitious Atheists, and acknowledge no Being that cor-
tesponds to our idea of a deity.”—Hume’s Natural History of Religion, sec. 4.
“ sW T»v xrlravrcc. 3 B„'XSi Herodotus.
D1SS. III. 3 M
458
PRELIMINARY DISSERTATIONS.
but, for the most part, they had some tradition
about the birth oi each of them. Indeed, several
of them were confessedly dead men, whom they
imagined to have been raised to the ranks of the
gods by their great deeds on earth. Thus Romu¬
lus, the founder of Rome, was worshipped by the
Romans under the title of Quirinus. And Her¬
cules, and many others, worshipped by the ancient
Pagans, were deified men, supposed to have gained
immortality, by their eminent virtues, and espe¬
cially by their feats of war.
The Northern nations, however, thought that
the gods they worshipped were not immortal, but
doomed finally to perish, after a very long life.1
These gods, nevertheless, are supposed, most of
them, to have answered to the Greek and Roman
gods, though with different names. Of these
names we have still a kind of record in the names
of the days of the week, which were dedicated
by our Pagan forefathers, each to one of their
gods.2 Many of the Jews, and of the early Chris¬
tians, seem not to have disbelieved the existence
of the heathen gods, but to have considered them
as evil demons whom it was impious to worship.
They did, indeed, often deride the Heathen for
worshipping images, “ the work of men’s hands,
wood and stone.” (Isa. xliv.) But it is plain
that any one who so worships, must believe that
there is some living spirit residing in the image,
or somehow connected with it. For no one could
pay adoration to a mere stone, believing it himself
to be nothing more than a mere stone. And it
appears that many of the Jews and early Chris-
tiansbelieved the Beings thatwererepresentedby
the heathen idols to be demons. Thus we find the
Jews calling Beelzebub the prince of the demons,
and blasphemously attributing to him the mira¬
cles of our Lord. Now Beelzebub was the Phi¬
listine god of Ekron. (2 Kings i.)
And certainly the character which the Pagans
attributed to their gods, was very much that of
evil demons. The very best of these gods were
represented by them as capricious and profligate
tyrants, whom they worshipped more from fear
than love. One, in particular, who was especially
dreaded, was Pan, the god of shepherds. In par¬
ticular, they attributed to him all sudden and
unaccountable terrors, such as sometimes seize
armies or other large bodies of men, and which
have thence received the name of Panic. Their
images represent him as partly in the human
form, and partly in that of a goat, with horns and
cloven hoofs. And hence it is, that by a kind of
tradition, we often see, even at this day, repre¬
sentations of Satan in this form. For, the early
Christians seem to have thought that it was he
whom the Pagans adored under the name of Pan.
This is certain, that several savage tribes at
this day profess to believe in a good god, and an
evil one ; and address all their worship, and
offer their sacrifices to the evil one. They sup¬
pose that the Good Being will, of his own accord,
without being asked, do all the good in his power;
and all their prayers and offerings are to the Evil
one—or to several evil Beings—whose malice
they hope to soften.3
The images and pictures of the gods of the
ancient Egyptians, and of the Hindoos at this
day, are usually strange monstrous figures, half
man and half brute. And such was the Philis¬
tine image of Hagon, which was half man and
half fish.4 The Greeks and Romans, on the con¬
trary, represented the greater part of their deities
as handsome men and women ; but the image of
Pan and some others were exceptions. And the
emblem5 of Diana at Ephesus, which they wor¬
shipped as having “ fallen down from Jupiter,”
is said to have been a rude, shapeless stone. It
was most likely an aerolite—one of those stones
which do really sometimes fall from the sky. So
1 “ Till Lok has burst his tenfold chain;
. . . . till substantial night
Has reassumed her ancient right.”—Gray.
3 The first day of the week was dedicated, as its name shews, to the sun, and the second to the moon ; Tuesday was sacre
to Tuisco, the same as the Roman Mars,- Wednesday to Woden, who is supposed to be the same with Mercury; Thursday to
Thor, that is Jupiter ; Friday to Friga, who was the Venus of the Romans; and Saturday to Saturn.
3 We have an amusing instance of this tendency of the human mind in the anecdote (a true one), of the schoolboy w o
was observed to bow in church whenever the name of Satan was mentioned; and being asked the reason, replied, “ I was
afraid he might do me some harm.”
4 The name does actually signify a fish. _
6 In our version (Acts xix.), it is called “ the image which fell down from Jupiter,” but the word “ image” is supplied y
the translators ; the original merely speaks of their being worshippers, tou Atomrovs, of “ that which fell down from Jupiter.
DISSERTATION THIRD.
459
probably, is also the black mass of stone at
Mecca, in the Caaba, venerated by the Maho¬
metans. For though Mahomet was opposed to
idolatry, he found the veneration of the Arabians
for this stone to be so great, that he did not ven¬
ture to oppose it.
As for the kind of worship which the Pagans
paid to their gods, it was very much what might
have been expected, considering what kind of
Beings these gods were, according to their own
accounts of them. When Moses is cautioning
the Israelites against being led away by the ex¬
ample of their idolatrous neighbours, he says,
“ Every abomination unto the Lord, which he
hateth, have these nations done unto their gods ;
for even their sons and their daughters, have they
burned in the fire unto their gods.” And the
inhabitants of the South Sea Islands, at this day,
offer human victims to their gods; as did also
the people of Mexico. The grossest profligacy,
and the most atrocious cruelties, were not only not
forbidden by the Pagan religions, but were even
a part of their religious worship ; especially at
the festivals of Bacchus.
And even the best of their gods were suppos¬
ed to be more gratified by costly offerings and
splendid temples, than by a pure and virtuous life
in their worshippers. This, indeed, was quite
natural; since these gods were described as not
only themselves committing the most abominable
actions, but as patrons of such actions. Mercury,
for instance, was reckoned the god, not only of
traffic, but of cheating; and the Romans had a
goddess of thieves, called Laverna,1 who was re¬
gularly worshipped, as well as the rest. Mars
and Bellona are described as delighting in human
carnage. And indeed, there are in modern lan¬
guages, words still in use, derived from the Pagan
religions, and generally signifying somethingemZ.
For instance, the words Martial, Panic, Bacchana¬
lian, Jovial, and many others that might be added.
As for the notions of the ancient Pagans re¬
specting a future state ; the Popular Mythology
of the Greeks and Romans did certainly contain
ample descriptions of a life after this, and of the
places prepared for the reward and punishment
respectively of the virtuous and the wicked. It
might indeed be urged with truth, that this My¬
thology, resting as it did on no other evidence
than that of vague, and incoherent, and contra¬
dictory traditions, could not afford any rational
assurance of a future state. And such, of course,
must be the case with the notions of Pagans of the
present day on the subject, as well as with those
of the barbarian nations of antiquity, of whose
Mythology we have no distinct and authentic ac¬
counts. How far the doctrine of a future state
did or does prevail as a matter of serious belief,
in those nations, it is by no means easy to deter¬
mine on sufficient evidence. In those of modern
times it is also difficult, if not impossible, to de¬
cide whether, and to what degree, some parts of
their religion may have been derived, through a
remote and corrupt tradition, from the Gospel.
The fairest mode of trying the question, therefore,
seems to be, by examining the opinions that pre¬
vailed before the promulgation of the Gospel.
And these afford, as we have said, no well-founded
assurance. Nor again, did the Pagan Mythology
inculcate the doctrine of a resurrection ; and it
was in many other points greatly at variance with
what Christians receive as the authentic and true
accounts. Still it must be admitted that a sys¬
tem so far correct in its outline, as to contain the
notion of a just judgment and a state of retribu¬
tion hereafter, to be influenced by our conduct
during the present life, would in some degree
supply the want of the Gospel revelation on these
points, provided it were (on whatever evidence)
fully and firmly and generally established among
the mass of the community. But that this was
not the case with respect to the accounts of a fu¬
ture state current among the ancients, is the con¬
clusion which will present itself to any one who
examines the question fully and candidly. We
say fully and candidly, because one whose re¬
searches are very limited, will not be unlikely to
have met with such passages only in ancient
writers as would, of themselves, lead to a con¬
trary conclusion; and one who is strongly pre-
1  “ Pulchra Laverna,
Da mihi fallere, da justo sanctoque videri;
Noctem peccatis, et fraudibus objice nubem.”—Horace.
460
PRELIMINARY DISSERTATIONS.
possessed in favour of that conclusion, will con¬
fine his attention to those passages, seeking only
to explain away all that militates against it.
The truth is, there are many passages to be
found (and that frequently in the same authors)
of each description; some that seem to imply the
general belief, and others the disbelief, of the ac¬
counts of a future life. And some have dwelt on
the numerical superiority of those passages that
favour the doctrine; as if a book were to be re¬
garded in the same light as a legislative assem¬
bly, in which we have only to count the votes
on each side, and consider the decision of the
majority as that of the whole. But it should be
remembered that, in such a case, the expressions
which negative the* belief, are entitled to far the
greater weight. For there can be no doubt that
the fables of Elysium and Tartarus were a part of
the popular religion, which it was usually thought
decorous to speak of with respect: and the doc¬
trine of a future state was regarded as especially
expedient to be inculcated on the vulgar, in or¬
der to restrain them in cases beyond the control
of human laws ; so that a good reason can be as¬
signed for a philosopher’s appearing to consider
the doctrine as indubitable, though he neither be¬
lieved it himself, nor could flatter himself that it
was so generally believed as he might think de¬
sirable : whereas, on the other hand, no reason
whatever can be assigned for any one’s treating
it as a fable, if he really did believe it.
When, then, we find Socrates and his disciples
represented by Plato as fully admitting, in their
discussion of the subject, that “Men in general
were highly incredulous as to the soul’s future
existence,” and as expecting that it would at the
moment of our natural “ death, be dispersed (as
he expresses.it) like ah* or smoke, and cease alto¬
gether to exist. So that it would require no lit¬
tle persuasion and argument to convince them
that the soul can exist after death, and can retain
anything of its powers and intelligence.” When
we find this asserted, or rather alluded to, as no¬
toriously the state of popular opinion, wre can
surely entertain but little doubt that the accounts
of Elysium and Tartarus were regarded as mere
poetical fables, calculated to amuse the imagina¬
tion, but unworthy of serious belief.
Again, the testimony of Thucydides, not as to
the professed belief, but as to the conduct, of the
Athenians, under those trying circumstances in
which the near approach of death impresses the
most forcibly the thought of a future state on the
minds of those who expect it—his testimony, we
say, as to their conduct on such an occasion, must
alone prove almost decisive of the question. For
it will hardly be denied, that those who firmly
believe in a future state, or even regard it as a
thing highly probable, however the pursuits and
occupations of this world may have drawn off*
their attention from it, will be likely, when death
evidently draws near,—death, not in the tumult¬
uous ardour of battle, but in the calm, yet resist¬
less progress of disease,—to think with lively and
anxious interest of the life of another world. If
they have any apprehensions at all of judgment
to come, they will usually wish to “ die the death
of the righteous,” even though they may not have
been willing to lead the life of the righteous.
Even those who have been in some doubt respect¬
ing this truth, or wTho have studied to keep it out
of sight, are often found to believe in it the most
firmly at that awful moment, when they would
be most glad to disbelieve it, and then to think
most of it, when the thought is most intolerable.
It is not necessary for the present purpose to
contend that what has been just said constitutes
a rule without exception ; let it be admitted
only as applying to the generality, or even to a
considerable portion merely, of mankind (and
thus far, at least, we are surely borne out, both by
reason and experience) ; and let any one, with
these principles before him, contemplate the
picture drawn of the pestilence which ravaged
Athens during the Peloponnesian war, by that
judicious historian who was an eye-witness, and
a partaker of the calamity. Whether the ancient
poets or philosophers be regarded as the better in¬
structors in the doctrine of a future state, Athens
had no deficiency in either ; and a plague so wide-
spreading, so irresistible, and which brought with
it to those whom it seized (as we are expressly
told), such an utter despair of recovery, may be
fairly expected to have had the effect, in some
minds at least, of awakening whatever belief, or
even suspicion, they might have entertained re¬
specting Tartarus and Elysium, and of calling
into action their fears and hopes on the subject.
DISSERTATION THIRD.
461
We might expect to find some of them, at least,
bewailing their sins, making reparation to those
they had injured, and in every way striving to pre¬
pare for the judgment that seemed impending.
The very reverse took place. The historian
tells us, that <f seeing death so near them, they
resolved to make the most of life while it lasted,
by setting at nought all laws, divine and human,
and eagerly plunging into every species of pro¬
fligacy.” 'Nor was this conduct by any means
confined to the most vile and worthless of the
community; for he complains of a general and
permanent depravation of morals, which dated
its origin from this calamity. Nor again, does
the description apply to such only as had been,
either openly or secretly, contemners of the
whole system of the national religion ;• for we are
told, that “ at first, many had recourse to the
offices of their religion, with a view to appease
the gods ; but that when they found their sacri¬
fices and ceremonies availed nothing against the
disease, and that the pious and the impious alike
fell victims to.it, they at once concluded that piety
and impiety were altogether indifferent, and cast
off all religious and moral obligations.” Is it not
evident from this, that those who did reverence
the gods, had been accustomed to look for none
but temporal rewards and punishments from
them 1 Can we conceive that men who expected
thatvirtue should be rewarded and vice punished,
in the other world, would, just at their entrance
into that world, begin to regard virtue and vice
as indifferent % It is but too true, indeed, that
men have been found in countries where Chris¬
tianity is professed, so hardened, as to manifest,
even at the approach of death, no regard to the
judgment which Christianity teaches is to suc¬
ceed it; who have availed themselves of present
impunity for the commission of crimes, or have
endeavoured to drown thought in sensual excess;
but instances of this kind rather go to prove that
such men do not, than that the heathen did, be¬
lieve in a future retribution ; if by belief is to be
understood, not a mere unthinking assent, or a
mere non-denial of the doctrine, but a deliberate,
firm, and habitual conviction.
Those who have been long hardened in habits
of extreme profligacy, may ultimately become as
blind to all ideas of a future state, as if they had
never heard of it; but experience, as well as rea¬
son, forbids us to believe that, where the Gospel
is assiduously preached and accepted, such a de¬
gree of ignorance, or of depravity, can ever be ge¬
neral, much less universal.
And accordingly, it appears that the great
plague which desolated London, produced, on the
whole, an effect exactly opposite to that at Athens.
Some abandoned wretches, no doubt, took the
same advantage as the Athenians did, of the ca¬
lamity ; but the generality seem plainly to have
shewn that their belief of a future state, however
it might have lain dormant during a time of ap¬
parent security, and however easily it might be
thrown off on a return to such a state, was real
and deep-rooted. No instances are recorded there
of pious men renouncing their piety when they
saw death approaching : on the contrary, serious
devotion seems, for the most part, to have pre¬
vailed ; and if not reformation, at least alarm and
contrition, to have been generally produced among
sinners. Many are said, when attacked by the
plague, to have even rushed into the public streets,
confessing aloud and bewailing crimes long ago
committed, and never before imputed to them,
and earnestly seeking to make reparation.
Can we, then, on comparing two such cases
together, come to the conclusion, that in each the
notions respecting a future state were the same,
or at all similar ? Is not the inference obvious,
that, at least, the Athenians of that age considered
the accounts of a future life as no more than
amusing fictions, of whose utter falsity there was
no reason even to doubt ? And accordingly, when
Pericles is represented by the same historian, as
exhausting every topic of consolation, in his ad¬
dress to the friends of those who had fallen in
battle,1 he speaks of their glorious memory, and
of the hope of other sons to be born, who may fill
their place, and emulate their worth, but adds
not one word of their future life and immortality.
And that the prevailing belief, at other times,
and in other states, Greek or Italian, was the
same as at Athens at the period just spoken of,
there is at least a strong presumption till evidence
1 Thucyd., lib. ii., c. 35, et seq.
462
PRELIMINARY DISSERTATIONS.
of the contrary is produced. The Athenians
were noted for their religious devotion; the popu¬
lar mythology which prevailed among the other
Grecian states, and, we may add, at Home, was
the same, or nearly the same, with theirs; and
therefore may be presumed, in the absence of all
proof to the contrary, to have had the same re¬
sults in respect of the belief of a future life. In¬
deed, we find the younger Pliny,1 in his account
of the eruption of Vesuvius, in which his uncle
perished, recording, among the striking events of
that scene, the excitement of a feeling not unlike
that of the Athenians in the plague—viz., a ge¬
neral distrust of divine aid, arising from the no¬
tion that the gods themselves were possibly in¬
volved in the impending ruin.
The belief, then, of a life to come, though no¬
minally professed, cannot be considered as prac¬
tically forming any part of the creed of those
ancient nations with whom we are best acquainted.
Cicero acknowledges that the epistle of Sul-
picius to him on the death of Tullia, compre¬
hended every argument for comfort which the
case admitted ; yet we find in it no allusion to
the one topic which would have been uppermost
in the mind of a believer. It is no wonder,
therefore, that when at Athens, Paul came to
speak of the resurrection of the dead, some of his
hearers mocked; and that when Festus heard
him declaring the same doctrine, he exclaimed,
“ Paul, thou art beside thyself.”
So far, indeed, were the promulgators of Chris¬
tianity from finding the belief of a future state al¬
ready well established, that they appear to have
had no small difficulty in convincing of this truth
even some of their converts. Some of those who
denied a resurrection, may, indeed, with good
reason, be supposed to have looked for some other
kind of future existence; but when Paul finds
it necessary to urge “ if in this life only we have
hope in Christ, we are of all men most miserable
—let us eat and drink, for to-morrow we die,”2
it is plain he must have been opposing such as
expected nothing beyond the grave. And when
he exhorts the Thessalonians not to sorrow for the
deceased, “ even as the restz (of mankind), who
have no hope” we have the testimony, if we will
receive it, of one who knew better than we can,
the real sentiments of the heathen on this point.
It maybe said, however (and this, perhaps, is the
most prevailing notion), that little as the vulgar
believed in the doctrine of a future state, it was
received and inculcated by many eminent philo¬
sophers. But, in reality, the doctrine never was
either generally admitted among the ancient phi¬
losophers, or satisfactorily proved by any of them,
even in the opinion of those who argued in fa¬
vour of it. On the one hand, not only the Epi¬
curean school openly contended against it, but
one of much greater weight than any of them,
and the founder of a far more illustrious sect,
Aristotle, without expressly combating the no¬
tion of a future state, does much more—he passes
it by as not worth considering, and takes for
granted the contrary supposition, as not needing
proof. He remarks incidentally in his treatise on
courage, that “ death is formidable beyond most
other evils, on account of its excluding hope;
since it is a complete termination, and there does
not appear to be anything either of good or evil
beyond it." And in the same work, in discuss¬
ing the question whether a man can justly be
pronounced happy before the end of his life, he
proceeds all along (as indeed is the case through¬
out), on the supposition, that after death a man
ceases altogether to exist. And it should be ob¬
served, that his incidental and oblique allusion
to this latter opinion, implies (as we have said)
much more than if he had expressly asserted and
maintained it. In that case he would have borne
testimony only to his own belief; but as it is, we
may collect from his mode of speaking, that such
was the prevailing and generally uncontradict¬
ed belief of the rest of the world.
Of those philosophers, again, who contended
for a future state, it is to be observed, not only
1 Epist., lib. ii., Ep. 20.
2 Thus Catullus :—
Soles occidere et redire possunt:
Nobis cum semel occidit brevis lux,
Nox est perpetua una dormienda.
s 6l Xo/TTO/, not as in our version, others.
DISSERTATION THIRD.
463
that, as Dr Paley remarks, they did not, properly
speaking, effect a discovery ; “ it was only one
guess among many: he only discovers who
provesbut also, that (as has been said above)
their arguments did not fully succeed in convin¬
cing even themselves. Those which at one time
they bring forward as decisive proof, they seem,
at another time, to regard as hardly possessing
that degree of probability, which, now that the
doctrine is established, most are ready to allow
them. Cicero, especially, who is frequently ap¬
pealed to on this question, we find distinctly ac¬
knowledging, at least in the person of one of his
disputants, that though, while he is reading the
Phaedo, he feels disposed to assent to the rea¬
sons urged in favour of a future state, his con¬
viction vanishes as soon as he lays down the book,
and revolves the matter in his own thoughts;
which was the feeling probably with which the
author himself had written it. Many, indeed,
of the deistical writers of modern times have
come to much more decisive conclusions on this,
and also on many other points, than the ancients
did, and, indeed, than are fairly warranted by
any arguments which unassisted reason can sup¬
ply ; but this only affords a presumption of the
powerful, though unacknowledged and perhaps
unperceived influence which the Gospel revela¬
tion has exercised even on the minds of those
who reject it. They have drunk at that stream of
knowledge, which they cannot or will not trace
to the real source from which it flows.
As, however, even the faintest conjecture of a
future existence, though it must not be confound¬
ed with a full assurance of it, is, as far as it goes,
an approximation towards the knowledge of
truth; so also, notions considerably incorrect re¬
specting that existence, if they are but such as to
involve the idea of enjoyment or suffering, cor¬
responding with men’s conduct in this life, have
so far something of a just foundation, and of a
tendency to practical utility. This, however, ap¬
pears by no means to have been the case with the
systems of any, as far as we can learn, of those
ancient philosophers who contended the most
strenuously for the immortality of the soul. For
not only do they seem to have agreed, that no
suffering could be expected by the wicked in
another life, on the ground that the gods were in¬
capable of anger, and therefore could not punish ;
but the very notion of the soul’s immortality, as
explained by them, involved the complete de¬
struction of distinct pcrsonaZ existence. Their
notion was, that is, when they spoke their real
sentiments (for in their exoteric or popular
works, they often inculcate, for the benefit of the
vulgar, the doctrine of future retribution, which
they elsewhere laugh at), that the soul of each
man is a portion of that spirit which pervades
the universe, to which it is reunited at death, and
becomes again an undistinguishable part of the
great Whole, just as the body is resolved into the
general mass of matter. S6 that their immor¬
tality, or rather eternity, of the soul, was anterior
as well as posterior ; as it was to have no end,
so it had no beginning; and the boasted con¬
tinuance of existence, which, according to this
system, we are to expect after death, consists in
returning to the state in which we were before
birth; which every one must perceive is the
same thing virtually with annihilation.
Such, then, were the views which prevailed
among the most enlightened nations of antiquity
on this subject. On the other hand, the Hindoos
of the present day do seem to believe in a future
state of existence. They hold the doctrine of
transmigration, i. e., that the souls of all men (ex¬
cept those of extraordinary holiness) are doomed
to migrate into the bodies of various brutes, and
at length, if found worthy, are admitted into
heaven.1 And the kind of holiness which they
expect will entitle men to future happiness, con¬
sists not in virtuous conduct, but in rich offer¬
ings, and the performance of various ceremonies,
many of them excessively cruel; such as hang¬
ing themselves up by iron hooks plunged into
their flesh, and other self-inflicted tortures. And
a woman who burns herself alive along with her
husband’s corpse, and any one who drowns him¬
self in the sacred river Ganges, or gives himself
to be devoured by certain sacred alligators, or to
be crushed under the wheels of the sacred car of
the idol Juggernauth, is supposed to gain the
special favour of their gods.
1 The heaven of the Buddhists, howeverj is man,ifestly annihilation circuitously described.
464
PRELIMINARY DISSERTATIONS.
The real character, then, of the Pagan reli¬
gions, being such as we have described, we are
naturally led to wonder that the Israelites should
so often have fallen into idolatry, after having
had the true God revealed to them. Although
He had so earnestly warned them not to worship
any other gods, we find them continually joining
the worship of Baal and other heathen gods with
that of Jehovah. This appears to some persons
so strange as to be hardly credible ; and yet the
very same thing is going on, almost before our
eyes, in Christian countries at this very day.
For in all parts of Europe the most uneducated
portion of the people in remote districts are found
to believe in, and fear various superhuman Beings,
which are in reality no other than the gods of
their Pagan forefathers. And though they do
not give them the title of gods, they often pay
them great reverence, and make some kind of
offerings to them.
In some parts of the British Islands, Fairies
are believed in and venerated. In Scotland, be¬
sides these, we hear of Bogles, Brownies, and
Kelpies, as names of certain superhuman Beings
dreaded by the superstitious. In Denmark and
Iceland, we hear of Trolls; in Germany of Nixes,
and many other such Beings, who are supposed
to have power in human affairs. In Norway, the
country-people are said to make an offering of a
cake once a year to a demon which they dread;
and also of the first cheese that is made each spring.
In some parts of our own country, a cottier’s wife
will not venture to bake bread or churn butter,
without offering a portion to the fairies. And
several other such acts of superstitious devotion
are practised in various parts of Europe.
Now, there is every reason to believe that all
these Beings who are thus reverenced, are, as we
have already said, the very heathen gods which
were formerly worshipped in each country. And
the persons who shew them this reverence, and
who seek their help, and dread to displease them,
and aim at obtaining their good-will, are doing
exactly the same as the Israelites of old, when
they worshipped Baal, and Astaroth, and other
gods of the heathen.
But what misleads people in their notions on
this subject, is, that the words we use are not
the same as the ancient Pagans used. What
were formerly called by some name answering
to “ gods,” are now called fairies, or “ kelpies,”
or genii, &c., and the reverence shewn them is not
called worship ; and the offerings made to them
are no longer called sacrifices. And thus it is that
professed Christians deceive themselves by means
of words, and fancy that they are not paying wor¬
ship to any gods besides the Lord, though they
are doing the same thing under other names.
With respect to the way in which false reli¬
gions were first introduced, there can be no doubt
that they must have crept in gradually. For men
would not all at once forsake the Avorship of the
Great Creator, and forget his very existence, and
serve other gods instead of Him. But it is likely
that, Avhen they had come to imagine certain in¬
ferior spirits to reside in the sun and moon, the
sea, rivers, groves, &c., they would next be led
to call upon these Beings, in the hope that, per¬
haps, such prayers might be heard. And when
once the practice has arisen of men’s adding on
to the worship of the Most High, some invoca¬
tions of other inferior Beings, this latter kind
of Avorship always tends to prevail over and drive
out the other. Men seem to think that an in¬
ferior Being Avho approaches more nearly to their
OAvn nature, is more likely to feel sympathy Avith
them, and perhaps is also more likely to be gra¬
tified by their adoration and their offerings, than
the Supreme God. And even at this day there
are some Pagan nations Avho are said to acknoAv-
ledge the existence of a Great Being, who is the
Supreme Ruler of all things, but Avhom they think
it Avould be presumptuous for them to address ;
so that all their worship is reserved for some
supposed gods of a loAver order.
This at least is certain, that the Apostle Paul
expressly informs us (Romans i.) that false Avor¬
ship did not first originate among men from their
knoAving nothing, and having no means of know¬
ing anything, of the true God, and being left en¬
tirely to their oavh conjectures. For he distinctly
declares, that some at least, “ Avhen they knew
God, glorified him not as God,” and “ did not like
to retain God in their knowledge, but changed the
truth of God into a lie, and Avorshipped the crea¬
ture more than the Creator.”
DISSERTATION THIRD.
465
It is very probable (and this seems to have
been the Apostle’s notion) that many of the more
intelligent portion of mankind, in the days when
false worship first arose, did not themselves par¬
take of the superstitions of the weaker and more
ignorant, but encouraged those superstitions for
the sake of gratifiying the vulgar, or keeping them
in subjection to themselves, by means of a reli¬
gion suited, as they thought, to unenlightened
and feeble minds. Certain it is, that some dis¬
honesty of this kind has often been practised in
various ages and countries, and under various re¬
ligious systems. Men of education and intelli¬
gence have often thought themselves justified in
disguising, or concealing, or altering some por¬
tion of what they believed to be religious truth,
and teaching or encouraging the vulgar to believe
something different from what they themselves
believed. And this dishonest system has always
led, in the end, to the grossest corruptions, both
of doctrine and of morals.
One great cause, probably, of the multiplica¬
tion of gods among the Pagans, was the use of
images or pictures. When men had introduced
the practice of making some kind of emblem, in¬
tended to represent either the Supreme God, or
any other Being they worshipped, they would
easily be led to pay more and more veneration to
the emblem itself, so as to become what is pro¬
perly called “ idolaters,” that is, worshippers of
an image or picture. And it would often happen
that one set of men would venerate one image,
and others another somewhat different, though
originally designed to represent the same being.
And there would also be some difference in the
kind of worship paid to each of these images,
and in the tales related concerning it; so that by
degrees some of them would come to be consi¬
dered as so many distinct gods.
Thus it seems to have been a matter of doubt
whether there were not two Jupiters ; whether
there were one, or two, or three Mercuries ; whe¬
ther the Moon, and Diana, and Hecate, Avere three
goddesses or one ; and the like in many other in¬
stances. And, probably, this was one reason Avhy
the Israelites were so strictly charged, in the laAV
of Moses, to Avorship, all of them at one place,
“ Avhich the Lord should chuse to set his name
there,” lest, from having several different tem¬
ples, that barbarian and gross-minded people
should come to imagine there were several gods.
It often happened that different tribes of men
worshipped either different gods, or the same un¬
der some different emblem, and with different
ceremonies. And there is reason to believe that
the confusion Avhich is recorded as having occurred
at Babel—aftenvards called Babylon—and which
caused the dispersion of mankind into various
countries, Avas in reality a dispute among them
as to their Avorship of some god or gods. This,
at least, is certain, that the scheme mentioned in
Gen. xi. Avas something displeasing to God, and
therefore could not have been merely the build¬
ing of a tower. And it is plain, also, from the
Bible history, that some ages after the Flood
mankind had very generally fallen into gross ido¬
latry, though Ave are not told expressly when
and hoAV it Avas introdueed.
As for the ToAver of Babel, it is said indeed in
our version that a number of persons joined to¬
gether to build “ a toAver whose top should reach
to heaven” (our translators meant an exceeding
high toAver), in order that they might not be
“ scattered over the face of the whole earth; ”
and that God sent on them a confusion of lan¬
guage, Avhich caused them to “ cease building the
toAver, and scattered them.” But it is to be ob¬
served that the Avord “ reach ” is supplied by our
translators, there being nothing answering to it
in the Original, which merely says, “ Avhose top
to the heaA^ens.”
And the meaning doubtless is, that the top of
the toAver should be dedicated to the Heavens 
that is, that a temple should be built on it to Bel,
Belus, Zeus, or Jupiter; under which titles the
ancient Pagans Avorshipped the heavens. For Ave
find the historian Herodotus,1 Avho many ages
after visited Babylon, expressly declaring that
there Avas there, in his time, a very high toAver,
on the top of Avhich Avas a temple to Belus ; Avho,
he says, Avas the same Avith the Zeus of the
Greeks.
CT*ht>0S xa.1 ifA r5ro tn io», Si/a a-raS/a/v, tccjtv, Vov Tirodyeatovlv /uitnuTi rS IgS vrv^yos irrs^os cixedouwTat,
KU-1 • 0 tvgos xat st/ tutm too Tv^yui aXXoi Tv^yos ST/lisfinxs xai sts^o; {/.aXa. scrl t&utco, /ASXg/S & oxru wu^ywv’ * ^
Ev ds tu rsXtWK/a Tufifcp vtioi stiuti ussya;. liEKODOTUS, Book L, clxxxi.
DISS. III. 3 ^
466
PRELIMINARY DISSERTATIONS.
The ancient Pagans, it is well known, were
accustomed to erect altars to the Heavens, or to
the Sun, on “high places” (Numb, xxxiii. 52),
on the loftiest mountains. And as the land of
Shinar is a very fertile plain of vast extent, and
quite level, it seems to have been designed to
make a sort of artificial mountain on it—that is,
a very high tower—and to build a temple, on the
top of this, to their god Belus, and so establish
a great empire consisting of people worshipping
at this temple.
The “confusion” which God sent among them,
and which caused the tower to be less lofty than
originally designed, and dispersed many of the
people into other lands, was most likely not a
confusion of language, but a dissension about re¬
ligious worship. The word in the original lite¬
rally signifies lip.y And it is more likely that
it was used to signify worship than language.
A dissension as to that which was the very ob¬
ject of the building, would much more effectually
defeat the scheme than a confusion of languages.
For, labourers engaged in any work, and speaking
different languages, would in a few days, learn, by
the help of signs, to understand one another suffi¬
ciently to enable them to go on with their work.
But if they disagreed as to the very object pro¬
posed, this would effectually break up the com¬
munity.
As for the different languages now spoken in
the world, there is no need of explaining that by
any miraculous interference. For, tribes who
have not the use of letters, and have but little
mutual intercourse, vary so much from each other
in their language, after even a few generations,
as not to be able at all to understand each other.
But while, as was remarked before, we have no
express accounts of the first origin of the Pagan
religions, this at least is certain, that it was
not even pretended that these religions rested on
any evidence worth listening to. A Pagan s rea¬
son for holding his religion is, and always was,
that it had been handed down from his ancestors.
They did indeed relate many miracles, said to
have been wrought through their gods; but almost
all of these they spoke of as having been wrought
among people who were already worshippers of
those gods, not as having been the means of ori¬
ginally bringing in the religion. And all the
Pagan miracles were believed merely because
these were a part of the religion which they had
learned from their fathers. In a word, the reli¬
gion did not rest on the miracles, but the mira¬
cles rested on the religion.
The Christian religion was distinguished from
these by its resting on evidence—by its offering
a reason, and requiring Christians to be able to
give a reason for believing it.
THE MOSAIC DISPENSATION.
It is plain from Scripture history, that both
before the Flood and afterwards, God did, from
time to time, hold communication in some way
or other, with mankind—that is, with such as
continued faithful worshippers of Him.
To Noah, in particular, we find Him giving
commandments both before the Flood and imme¬
diately after it, and accepting sacrifice from him.
In a later age we read of divine commands issued
to Abraham, and promises made to him of pecu¬
liar blessings to a nation which should descend
from him through Isaac; and also of an extension
of blessings to all mankind through them—that
“ in his seed should all the nations of the earth
be blessed.” (Gen. xii., xxii.)
And although idolatry and gross wickedness
seem, in Abraham’s time, and afterwards, to have
overspread most parts of the world, still there
were some besides him and his family, who
retained the worship of the true God. For, in
the history of Abraham, we find mention of
Melchizedek, a king, who held also the office
of “ a priest of the Most High God.” (Gen.
xiv.)
1 rs-b (Septuagint).
DISSERTATION THIRD.
467
Jethro, again, the father-in-law of Moses, ap¬
pears to have been a worshipper of the true God;
and the prophet Balaam, though a wicked man,
is spoken of as a real prophet of the Lord.
It is probable, also, that some of the Egyptians
were worshippers of the Lord, though so many of
that nation had fallen into idolatry. For we
read of Joseph’s marrying the daughter of an
Egyptian priest (Gen. xli.), and though possible,
it does not seem likely, that so eminently pious a
man would have married the daughter of an idola¬
trous priest. This, at least, is certain, that the
historian Plutarch speaks of a certain portion
of the land of Egypt which was exempted from
the tax levied on the rest for the support of ido¬
latrous worship. And this, he says, was on ac¬
count of their being worshippers only of ONE,
whom they called Cneph, “ the unbegotten God.”1
And the plagues inflicted on Egypt by the Lord
God of Israel,2 the complete dominion He dis¬
played over the Beings the idolaters worshipped,
must, no doubt, have brought some of the Egyp¬
tians to acknowledge and worship Him. (Exod.
ix.) But we are told very few particulars of the
faith or the worship3 of the servants of the true
God, till we come to the time when Moses, by
divine command, delivered to the “ chosen”
(elect) “ people of Israel” that system of religion
which is called “ The LAW.”
Of this—the Mosaic law—we find a full ac¬
count in the last four Books of Moses. And these
should be carefully studied by any one who would
gain as accurate an understanding as possible of
the system under which that most remarkable
nation, the Israelites, were placed.
For our present purpose, it will be sufficient to
mark out the most important points which dis¬
tinguished the Mosaic Dispensation—the religion
of the Israelites—from what came before it, and
from what followed it; on the one hand, from the
religion of those worshippers of the true God who
lived before the time of Moses, and on the other
hand, from the Gospel-Dispensation—the reli¬
gious system under which we are placed.
The Law was designed to prepare the way for
Christianity—a religion intended for all man¬
kind—according bo the promise made to Abra¬
ham, that some person or persons descended from
him should prove a blessing to all nations. Yet
the Law itself was given to one people alone.
And accordingly, when the Apostles of Jesus
Christ, who were themselves Jews, converted
vast multitudes of Gentiles to Christianity, teach¬
ing them, among other things, to acknowledge
the divine origin of the Mosaic Law, they yet
taught them that the ordinances of that law did
not extend to Gentiles.4 (Gal. v.)
It is to be remembered, however, that before
the Gospel revelation, a Gentile was allowed, if
he wished it, to become a proselyte ; and thence¬
forth he was not regarded as “ unclean” (Acts
x.), and an “ alien” (Eph. ii. 11, 12), but only as
ranking next below the Israelites by birth.
And, moreover, Gentiles who, though they had
renounced idolatry, yet did not conform to the
whole Law, but only to a certain small number of
regulations, were admitted to worship in the outer
court of the Temple (“ the court of the Gentiles,”
1 Kings viii. 41), and to attend divine service in
the synagogues. These Gentiles are often alluded
to in the Book of Acts ( Acts x. 2 ; xiii. 16,26, 43 ;
xvi. 14 ; xvii. 4, 17), under the title of “ the de¬
vout,’’5 or “ they who feared God”6 (that is, the
Lord Jehovah), such as was Cornelius the cen¬
turion. And after the time of the Captivity, there
were, in various countries, many Jews residing
dispersed among the Gentiles ;7 and these Gen¬
tiles had thus an opportunity of learning (as a
1 Ay'mnrov ivra xu.) They were the inhabitants of Thebais.—Plutarch, Be hide et Osiride.
2 “ On all the gods of Egypt will I execute judgment.”—(Exod. xii. 12.)
3 It is the opinion of many learned men that it was the practice of the servants of the true God, in the earliest times,
to keep holy the last day of the week [Saturday] in memory of the close of the work of creation. And this seems probable,
though no such practice is expressly recorded. But their mode of observing the day could hardly have been altogether
the same with what was enjoined to the Israelites. To these the Sabbath seems to have been, in the particulars of the oh-
servance, a new and a peculiar institution. And accordingly we find, in the Prophecy of Ezekiel, the Lord saying, “ I gav\
them [the Israelites] my Sabbaths, to be a sign between me and them.”
4 “ Let no man judge you” (says the Apostle Paul, when writing to the Gentiles), “ in meat or in drink, or in respect
of an holyday, or of the new moon, or of the sabbath-days, which are a shadow of things to come; but the body is of
Christ.”—(Col. ii. 16.) 6 oS irtfoplvoi. 6 ol (pofiovpivot rov 0s<n^ _ ^
7 These are called “ the Jews of the Dispersion” (see the beginning of the Epistle of James); or simply “ the Dispersion.
468
PRELIMINARY DISSERTATIONS.
considerable number of them did learn) to know
and to serve the true God. But those Gentiles
who had no Jews resident among them had no
such opportunity.
Why it was that the Most High thought fit
to make a revelation to this one people, and not
at once to all the world, we cannot explain, and
must not presume to decide. Indeed, we can¬
not explain why the Gospel was not preached to
the very first generation of mankind ; and why
Jesus Christ came into the world just when He
did ; nor yet why many nations, in various parts
of the world, have been left, even to this day, in
the darkness of idolatrous superstition ; or in¬
deed, why any such thing as EVIL should exist
at all.
All this, we must conclude, would have been
explained to us in Scripture, if it had been neces¬
sary for us to understand it. As it is, any attempt
to explain these things is fruitless and presump¬
tuous. It is our business to inquire, not what we
should have done, had the regulation of things
been left to us, but what God has actually done,
and what He requires us to do.
We have the most satisfactory reasons for be¬
lieving that the Lawr of Moses was given by di¬
vine command ; and also that it was given to the
one nation of Israel, and not designed for the rest
of mankind.
One of the many marks one may perceive of
this design is, that it was a local religion. The
Israelites were directed to offer sacrifices, and to
worship three times a-year, at the one “ place
which the Lord should chuse to set his name
there” (that is, to place there the manifestation
of his presence and power); and they were strictly
forbidden to sacrifice anywhere else. (Deut. xii.
13.) And, accordingly, when the Temple at Je¬
rusalem had been finally fixed on as the chosen
place, the destruction of that Temple made it
thenceforth impossible for an Israelite to keep up
the chief ordinances of his religion.
Hence the final destruction of that Temple
abolished, manifestly and totally, the Mosaic sys¬
tem of religion.
And it is very remarkable that that religion is
almost the only one that could have been abolish¬
ed against the will of the people themselves, and
while they resolved firmly to maintain it. Their
religion, and theirs only, could be, and has been,
thus abolished in spite of their firm attachment
to it, on account of its being dependent on a par¬
ticular place. The Christian religion, or again,
any of the Pagan religions, could not be abolished
by any force of enemies, if the persons professing
the religion were sincere and resolute in keeping
to it. To destroy a Christian place of worship,
or to turn it into a Mohammedan mosque (as
was done in many instances by the Turks), would
not prevent the exercise of the Christian religion.
And even if Christianity were forbidden by law,
and Christians persecuted (as has in times past
been so frequently done), still they might assem¬
ble secretly in woods or caves, or they might fly
to foreign countries to worship God, according to
their own faith; and Christianity, though it
might be driven out of one country, would still
exist in others.
And the same may be said of the Pagan reli¬
gions. If it happened that any temple of Jupiter,
or Diana, or Woden, were destroyed, this would
not hinder the worshippers of those gods from
continuing to worship them as before, and from
offering sacrifices to them elsewhere.
But it was not so with the Jews. Their religion
was so framed as to make the observance of its ordi¬
nances impossible, when their Temple was finally
destroyed. It seems to have been designed and
contrived by divine providence, that as their law
was to be brought to an end by the Gospel (for
which it was a preparation), so, all men were to
perceive that it did come to an end, notwithstand¬
ing the obstinate rejection of the Gospel by the
greater part of the Jews. It was not left to be
a question and a matter of opinion, whether the
sacrifices instituted by Moses were to be con¬
tinued or not; but things were so ordered as to
put it out of man’s power to continue them.
But, moreover, this local character of the reli¬
gion shewed, from the very first, that it could not
be designed for all mankind.
And the same thing is indicated by the way
in which all the laws are expressed. For it is
remarkable that even those duties which, from
their very nature, must be duties for all men, such
as to worship the one true God only, and to hon¬
our one’s parents,—even these are enjoined to the
Israelites in commandments which expressly re-
DISSERTATION THIRD.
469
fer to that one peculiar people. “ I am the Lord
thy God, who brought thee out of the land of
Egypt; thou shall have none other gods but Me :
and “ Honour thy father and thy mother; that thy
days may be long in the land which the Lord thy
God giveth theef—that is, the land of Canaan.
Of course Christians are bound to practise these
and all other moral duties. But that is because
they are in themselves moral duties; not because
they are enjoined in the Law of Moses ; which
was designed for the one people of Israel.
Other commandments there were, relating to
matters originally indifferent, but respecting
which God laid down certain rules ; and required
the Israelites to comply with those rules in sub¬
mission to his will.
Some of these commandments related to reli¬
gious ceremonies or observances, such as the keep¬
ing of the Feast of the Passover—coming up to
the Temple at Jerusalem three times a-year—
abstaining from certain meats, and wearing cer¬
tain peculiar garments ; with other things of that
kind. These are commonly called ceremonial
laws.
And, again, there were other commandments
called civil laws ; being such as relate to matters
which the civil governors of any country have a
right to regulate, from time to time, as they think
best; and to enforce by penalties, such as im¬
prisonment, banishment, or death.
For, the Lord was not only the God, but also the
King (or civil governor) of this peculiar people ;
and enacted all such laws for their good govern¬
ment as the rulers of any other nation are autbo-
rised to enact and enforce, and to annul or alter
whenever they see fit.
Of this kind was the law that no man should
part with his landed property finally, but that, if
sold, it should return to him, or his heirs, at the
jubilee; and thatwrhich directed thatamanshould
marry his brother’s widow if his brother died
childless (Deut. xxv. 5, and Luke xx. 29), with
many other such laws.
Now, the ceremonial and the civil laws being
such as relate to matters in themselves indiffer¬
ent, are what are commonly called “positive pre¬
cepts those relating to points of natural duty
being called “ moral precepts.” And it is very
important to keep in mind the distinction be¬
tween these two classes of laws. Any thing en¬
joined by a positive precept is right because it is
commanded : any thing enjoined by a moral pre¬
cept is commanded because it is right.
Thus it was, to the Israelites, a duty to keep the
Passover, as it is to Christians to celebrate the
Lord’s Supper ; because divine commands to do
so were given, and it is a moral duty to obey di¬
vine commands. But there was no such duty be¬
fore those express commands were given.
On the other hand, to honour one’s parents is,
from the nature of the case, a duty of all men ;
and the Israelites were commanded to do so, be¬
cause it is right in itself.
Again, to abstain from all worship of false gods,
or of images, and to reverence the true God, is a
natural duty, and was enjoined to the Israelites
because it is so. But no one would say that it
is a natural duty to keep holy one day in seven,
rather than one in six, or in eight; or to keep holy
the last day of the week, rather than the first, or
any other ; or to abstain from kindling a fire
(Exod. xxxv. 3) on that day. But all this became
a duty to the Israelites when they had received
a divine command to observe in that particular
manner that particular day ; and so with other
commandments.
Again, the Mosaic Law was distinguished from
every other revelation ever bestowed on man, by
the great number and minuteness of its regula¬
tions, and the multitude of its ceremonial obser¬
vances. It gives exact directions to the Israel¬
ites as to their diet, their dress, and their mode
of life in many particulars.
One purpose answered by these numerous or¬
dinances, was to keep them quite distinct from
other nations ; that they might be the better pre¬
served from falling into the idolatrous worship of
their neighbours, and might be marked out, both
to them and to themselves, as the Lord’s peculiar
people.
And moreover, it was needful for a half-bar-
barian and gross-minded people, such as the an¬
cient Israelites, to keep up in their minds the
thought of their religion, by a great number of
outward ceremonies and observances. These
served to remind an Israelite continually of the
God whose servant he was, by his being required
from day to day to observe certain rules, and to
470
PRELIMINARY DISSERTATIONS.
perform certain acts, as a sign of his obedience
to the Lord, and as a part of his religious duty.
And a great part of the ceremonies of this law
had also a typical meaning. In particular, the
Passover, and all the other sacrifices of animals,
were types representing the sacrifice of Christ on
the cross for man’s redemption. And, accordingly,
we find the Apostle Paul expressly calling Him
“ our Passover, who is sacrificed for us.” (1 Cor.
v. 7.) For as the blood of the first paschal-lamb
sprinkled on the door-posts of the Israelites in-
Egypt (Exod. xii. 7) was to preserve their first¬
born from the destroying angel which slew the
Egyptians, so the sacrifice of Jesus Christ brings
eternal deliverance and salvation to those who
will be truly his disciples. And He is thence
called in Scripture, “ The Lamb of God, who
taketh away the sin of the world.”
And throughout the New Testament, there are
numerous references to the sacrifices and other
ceremonial ordinances of the law, as types repre¬
senting the redemption by Christ, and foreshow¬
ing the Gospel dispensation.
But all this was not understood, nor designed
to be understood,by the Israelites to whom Moses
delivered the Law. They were only required to
observe strictlyand carefully the directions given,
without understanding the full meaning of all
that was ordained. The Law of Moses, there¬
fore, was like some important document written
in cypher, or in an unknown language; which a
man is directed to preserve very carefully till
such time as he shall be furnished with a key to
the cypher, or a translation. Just so, the Gos¬
pel, when it was revealed, furnished an interpre¬
tation of many things in the Mosaic Law, which
had been before unintelligible as to their inward
meaning.
And this is what the Apostles mean when they
speak of “ making known the mystery of the
Gospel.” For “ mystery” signifies, in their use
of the word, something that has been concealed,
and is afterwards revealed and explained. (Eph.
vi. 19.)
Another distinguishing character of the Mosaic
Law was, that it was enforced by a system of tem¬
poral rewards and judgments, administered ac¬
cording to an extraordinary providence.
The Israelites were promised, as the reward
of obedience, long life, and health, and plentiful
harvests, and victory over their enemies. And
the punishments threatened for disobedience,
were pestilence, famine, defeat, and all kinds of
temporal calamity. (Dent, xxviii.)
And the history of this most remarkable peo¬
ple is full of examples of the fulfilment of these
promises and threats.
In the Books of Moses himself, and the his¬
torical books that follow, we find abundant in¬
stances of both kinds recorded. The Lord (Je¬
hovah) was, as has been remarked above, not only
the God, but also the King (or civil governor) of
this peculiar people. And hence the word “Theo¬
cracy” is often applied to the system under which
the Israelites lived. Hence, too, it was, that
among them the worship of other gods was made
a capital crime; because, under such a system,
it amounted, in fact, to high treason. (Dent. xvii.
2.) For, it is to be remembered, thatthe Pagans re¬
garded their gods as their temporal rulers; looking
to them for victory and success of all kinds, con¬
sulting them, and acting on their supposed di¬
rections. The ideas of tutelar god, and king, were
so blended in the minds both of the Pagans and
the Israelites, that an Israelite could not worship
Baal or Moloch, without so far withdrawing his
allegiance from Jehovah his King. And even
when they were ruled by judges, or by kings,
they were under this theocracy; these rulers
being considered as merely agents or deputies of
the Lord their King, and appointed or removed
by Him. He issued direct commands, from time
to time, to the nation, or their governors, as to
various temporal concerns, such as are regulated
by the supreme rulers of each State. (1 Sam. xv.)
And as all rulers enforce their commands by
temporal penalties on the disobedient, such as
forfeiture of goods, bodily chastisement, or death,
so the Lord enforced on the Israelites obedience
to his commands by temporal rewards and punish¬
ments, distributed according to an extraordinary
providence.
It appears to have been designed in that dis¬
pensation to exhibit to mankind a sensible speci¬
men, or rather representation, by way of proof,
of that moral government of God, the system of
which is but imperfectly displayed in the world
DISSERTATION THIRD.
471
at large; and which is to be completed, and fully
realised, only in a future state.
It would be inconsistent with the present oc¬
casion to enter into a full explanation and defence
of this hypothesis : let it be allowed, however, to
adopt for the present, the supposition, merely as
a supposition, that the Mosaic dispensation was,
in part, designed for the purpose just mentioned;
that we may examine how far the peculiar cir¬
cumstances of that dispensation correspond with
and are explained by it. It would manifestly be
necessary, then, with a view to the object in ques¬
tion, that the Israelites should be exhibited as
uniformly and regularly rewarded or punished,
according to their obedience or disobedience to
the divine commands. And moreover, in order
that the correspondence of their situation with
their conduct might be more conspicuously dis¬
played, it was necessary that they should be na-
tionally as well as individually, prosperous or un¬
fortunate, in consequence of their good or ill con¬
duct; since the fate of individuals would have
been too obscure to engage general attention. It
was requisite, for the same reason, that the obedi¬
ence required of them should not consist in moral
rectitude alone ; because in that case the corres¬
pondence of their circumstances to their behaviour
would not have been sufficiently manifest. For
moral virtue consists, chiefly, in purity of motives,
and propriety of inward feelings ; concerning
which other men cannot with any certainty form
a judgment. It was requisite, therefore, that
their obedience should be tried in the practice of
external rites, and in a conformity to certain
positive ordinances. For these observances,
though originally matters of indifference, yet, as
we have before observed, assume a moral charac¬
ter, and become duties, when enjoined by divine
authority; and the obedience or disobedience of a
people on such points, is a matter open to general
observation, and on which no one would be liable
to mistake.
Lastly, with the same view, it was no less re¬
quisite that the rewards and punishments also,
which should be the sanction of such a law, should
be of a nature no less palpable and open to gene¬
ral observation; and should therefore not consist
in anything inward and invisible, as in peace of
mind, and in horrors of conscience; nor in the
hopes and fears of a future state; but in the im¬
mediate and conspicuous distribution of outward
worldly prosperity and adversity.
The close correspondence, in all points, of the
dispensation actually given, with the foregoing
description, is no slight presumption that the
object of that dispensation was, in part at least,
such as we have supposed,—viz., to exhibit to
mankind, (that is, to those who should be in early
times neighbours to the Israelites, or have any
intercourse with them, and subsequently to us,
and to all others who should read their history,
and view their present fate) ; to exhibit, we say,
a striking picture of God’s moral government,—
to convince all men of his superintending provi¬
dence,—and to instruct them in the principles of
justice, by which his dealings with them will be
regulated.
We must, however, carefully keep in mind the
distinction between an extraordinary providence,
such as that under which the Israelites were
placed, and the ordinary divine providence by
which the world generally is governed, and which
is sometimes called the “ course of Nature.”
God has appointed that, as a general rule,
though not an invariable one, good conduct shall
lead, on the whole, to temporal success and wel¬
fare, and ill conduct to misfortunes of various
kinds. Thus, the general tendency of industry
and frugality is to lead to prosperity; and of idle¬
ness, improvidence, and extravagance, to poverty
and distress. Temperance conduces, on the whole,
to health, and intemperance usually brings on dis¬
ease and death. The quarrelsome, the hard¬
hearted, and the unjust, are likely to be hated or
despised ; while gentleness and kindness tend, in
general, to procure a man the good-will of his
neighbours; and (according to the proverb) in the
long run, “ honesty is the best policy.”
Accordingly, in the ordinary course of events,
we are generally able to trace men’s good or ill
success in life, to their good or ill conduct. For
instance, when a man who has lived a life of sen¬
suality and extravagance is ruined in health and
in fortune, we can perceive the connection be¬
tween his misery and the vice and folly that have
naturally caused it. Or again, if an honest, in¬
dustrious, and prudent man becomes rich, we say
that this is according to the natural course of
472
PRELIMINARY DISSERTATIONS.
things. And so in other such cases. We do not
mean, when we speak thus, that the “ natural
course of things ” is not regulated by divine pro¬
vidence, but merely that such is the ordinary,
established, and regular course of God’s govern¬
ment of the universe.
On the other hand, when any occurrence is
spoken of as “ supernatural” (or “ miraculous”),
although the word “ providential ” is sometimes
applied in the same sense, any one who believes
that God is the supreme disposer of all events,
cannot mean that such an occurrence is more pro¬
vidential than others, but merely that it belongs
to God’s extraordinary providence.
And in any such case we can trace no connec¬
tion between the sin and the punishment, or be¬
tween the good conduct and the reward, except
so far as we learn it from express revelation. For
instance, when Korah (Numb, xvi.) and his com¬
pany were swallowed up by an earthquake, as a
punishment for having “ provoked the Lord,” we
know that this was a judgment on them for that
sin, solely because Moses, by divine command, ex¬
pressly declared the sin, and foretold the punish¬
ment.
And again, when the Israelites were defeated
before Ai, as a judgment for the transgression of
one of them (Josh, viu), and when the land of the
ten tribes was burnt up with drought, in the
days of Ahab, as a punishment for their idolatry
(1 Kings xvii.), we can trace no natural connec¬
tion between the sin and the consequences of it;
and we know this connection only because we are
expressly told it in Holy Scripture.
Would it not, then, be in the highest degree
presumptuous for any one of us, uninspired men,
to pronounce judgment on those who are cut off
by sudden death, or who are visited by such cala¬
mities as an earthquake, a famine, or a pestilence l
Shall we take upon ourselves to declare the coun¬
sels of the Most High, when He has not revealed
them 1 and, in defiance of our Master’s express
warning, proclaim that these men were sinners
above those who have escaped such a fate \
And yet some persons do occasionally presume,
without any commission from Heaven, to pass
judgment on their neighbours, and to declare that
such and such a calamity is a mark of divine dis¬
pleasure, and a punishment for such and such a sin.
Such men are like the false prophets of old—
their language is, “ Thus saith the Lord, when the
Lord hath not spoken.” Whatever high preten¬
sions they may make, it is not piety, but daring
impiety, thus to mimic the voice of God’s in¬
spired messengers, and to come forward, without
any divine commission, setting forth their own
fancies as revelations from Heaven. It is not
wisdom from above, but gross ignorance of both
the volumes which the same divine Author has
opened for our instruction—the volume of Nature,
and the volume of Revelation,—that leads men
thus to confound the ordinary and the extraordi¬
nary dispensations of his Providence. Some
design, no doubt, the Allwise Governor of the
world must have,in all his dispensations, whether
of sorrow or of joy. He sends want, and He
sends abundance,—He allots affliction, and tem¬
poral deliverance and prosperity, not at random,
but according to some fitness which He perceives
in the respective parties, to be the recipients of
these dispensations.
The hardships undergone by the Apostles, they
were exposed to, we may be assured, for some
good reason; and so also, health, plenty, and
every kind of temporal success, are doubtless be¬
stowed with some wise design on those who ob¬
tain such advantages. But when He has not
thought fit to reveal what his designs are, it is
not for us, shortsighted mortals, to pronounce
upon them, and presumptuously to usurp the of¬
fice of his prophets. “ Wherefore judge no¬
thing,” says the Apostle, “ before the time, until
the Lord come, who will bring to light the hid¬
den things of darkness, and will make manifest
the counsels of the hearts ! and then shall every
man have [his] praise1 of God.”
The notion, however, that calamity is necessa¬
rily a token of the divine displeasure, was one
Avhich the Jews very much clung to—and very
naturally; inasmuch as that particular nation had
been originally placed under such a system of
temporal rewards and punishments. They found
it hard to believe, therefore, in the change of that
system, when the Gospel was preached. And ac-
1 o mu-r/oi: viz., whatever he is justly entitled to. The Greek article has the force of our pronoun.
DISSERTATION THIRD. 473
cordingly, the sufferings and death undergone by
Jesus and many of his disciples, formed the chief
stumbling-block to the Jews (1 Cor. i. 23), most
of whom would not believe that He could be the
true Christ, or a favoured servant of God; because
they regarded His sufferings as a proof of the
divine disfavour.
And their objection to Him, on this very ground,
was accordingly foretold by the Prophet Isaiah
(Isa. liii.)- “ a man of sorrows and acquainted
with grief; and we hid, as it were, our faces from
Him“ we did esteem Him stricken, smitten
of God and afflicted,” &c. &c.
It seems strange to us that so many of the Jews
should refuse to be convinced by such prophecies
as this. But it is much more strange that there
should be some Christians, who, though professed
followers of a Master who was crucified, still per¬
sist in regarding temporal calamities as a proof of
the divine displeasure against those who are so
visited; and that there should be Christians who
presume, against their great Master’s express
prohibition, to declare what the sins are that
have called down on their neighbours such cala¬
mities.
Some persons, however there are, who care¬
lessly use the words “providential” and “miracu¬
lous,” merely to denote any thing unusual and
strange. They talk of a “miraculous” escape
from some danger, meaning merely a wonder¬
ful escape; and of a man’s being delivered “ pro¬
videntially,” when they mean only that the de¬
liverance was striking and remarkable.1 But
it is best to abstain from this loose kind of lan¬
guage, lest we should be understood to mean
either that other events are not providential, and
that God’s government does not extend to the
ordinary course of things ; or else, that we—un¬
inspired men—are permitted to decide (in cases
where there is no evident miracle) what are the
designs of the Most High, and what are the oc¬
currences that do, and that do not, belong to his
extraordinary dispensations.
The nation of Israel was, as we have said,
placed under an extraordinary providence, which
allotted to them victory or defeat,—plenty or fa¬
mine,—and other temporal blessings and punish¬
ments, according to their conduct. And these
were the rewards and punishments that formed
the sanction of the Mosaic Law. As for a future
state of retribution in another world, Moses said
nothing to the Israelites about that. Whatever
may at any time have been revealed to himself,
and to some other highly favoured individuals, on
that subject, it does not appear that he was com¬
missioned to deliver to the people any revelation
at all concerning a future state. This was reserv¬
ed for a GREATER than Moses, and for a more glo¬
rious dispensation than his Law'. For as we read
in the Epistle to the Hebrews “ the law made
nothing perfect; but the bringing in of a better
hope did” (Heb. x.)—namely, the promises given
through “ Jesus Christ, who brought life and im¬
mortality to light, through the GospeV
W hy Moses was not instructed to reveal this
momentous truth, is a question which will natu¬
rally occur to every one. It is a question which
we are not competent completely to answer; be¬
cause, as has been elsewhere observed, we cannot
presume to explain why the Gospel was reserved
for that precise period at which it was proclaim¬
ed. But that inquiry,—why a different and more
imperfect dispensation was needful to prepare the
way for the Gospel,—being waived, as one sur¬
passing man’s knowledge and pow'ers, it is easy
to perceive that the revelation of the doctrine in
the Mosaic Law would have been neither neces¬
sary nor proper. It was not necessary for the pur¬
pose of affording a sanction to the Law of Moses,
because the Israelites alone, of all the nations of
the world, were, as we have seen, under an ex¬
traordinary providence.
The reason some give for distinguishing some particular events as “ providential,” is in truth a reason on the opposite
side. An unexpected recovery from a disease which seemed hopeless, or a wonderful escape from a shipwreck, &c., is,
hey say, more striking to their minds, and impresses them more with a sense of the goodness of Providence than ordinary-
occurrences. O J
Now, for this very reason, they should labour the more carefully to bring themselves to reflect on the daily benefits they
receive from “ Him in whom we live and move and have our being.” The more prone we are to pass by with careless in-
i erence our being preserved from falling into a dangerous sickness, or from being shipwrecked at all, the more we
s on d study to bring our minds to dwell on such preservation ; which is, in truth, no less “providential” than a man’s being
delivered out of a sickness or a shipwreck.
DISS. III. 3 0
474
PRELIMINARY DISSERTATIONS.
The necessary foundation, therefore, of all reli¬
gion, “ that God is a rewarder of them that dili¬
gently seek him,” did not require, as it must in
all other nations, the belief in a future retribu¬
tion, to remedy all the irregularities of God’s
ordinary providence, which among this peculiar
people did not exist, at least in the same degree
and form, as among all others. Nor, again, would
it have been proper for Moses, commissioned as
he was to promulgate, not the Gospel, but the
Law, to proclaim that life and immortality which
the Gospel was destined to “bring to light;” much
less, to represent eternal happiness as attainable
otherwise than through the redemption by Christ,
which the Gospel holds out as the only efficacious
means of procuring it.
And accordingly it is observable that the slight
hints of this doctrine which the books of the pro¬
phets contain—the faint dawnings, as it were, of
a scheme which was to bring “ life and immor¬
tality to light,” and which appear more and more
bright as they approached the period of that more
perfect revelation, are in perfect consistency with
the rule we have supposed Moses to have ob¬
served ; since it is in proportion as they give more
and more clear notices of the Redeemer to come,
and in almost constant conjunction with their de¬
scriptions of his mission, that the immortal life,
to which He was to open the road and lead the
way, is alluded to by the prophets; and also in
proportion as the extraordinary and regular ad¬
ministration of divine government in this world,
by which the Law hadbeen originally sanctioned,
and under which the Jews had hitherto lived,
was gradually withdrawn. That it was in these
writings, and not in those of Moses, that the Jews
must have sought for indications of a future state,
is strongly confirmed by the opinion of that cele¬
brated and learned divine, Joseph Mede, who de¬
clares that he cannot tell on what Scripture autho¬
rity the Jewish Church could have founded their
belief in a future state, except the well-known
passage in Daniel; and even of that, it may be
observed, that it does not necessarily imply a re¬
surrection of all men. Doubtless it did not escape
Mede that there are in the other prophets many
allusions to a future state, which were so under¬
stood by the inspired authors themselves, as they
are by us Christian readers; but it does not fol¬
low that the great mass of the people—any be¬
sides the studious and discerning few—would be
able clearly to perceive such meaning, especially
when a different interpretation of those very pas¬
sages applicable to temporal deliverances, might,
without destroying their sense, be adopted. No¬
thing appears to us more evident than the descrip¬
tion in Isaiah, for instance, of a suffering Mes¬
siah ; yet we well know that a prosperous and
triumphant temporal prince was generally ex¬
pected by the Jews, and that the frustration of
this hope was the grand stumbling-block of the
unbelieving among them.
So also many passages of the prophets, which
convey to Christians, who have enjoyed the Gos¬
pel revelation, the intimation of a future state,
(at least in their secondary sense), might very
easily be otherwise understood; or, at least,
might appear not decisive, to those who lived
before Jesus Christ had “abolished death, and
brought life and immortality to light through the
Gospel.”
We are told, indeed, that even at a time long
antecedent to that of Moses, Abraham “ eagerly
desired1 to see the day of the Lord Jesus ; and he
saw it, and was glad.” In these words our Sa¬
viour is doubtless alludingto the sacrifice of Isaac,
and to Abraham’s being instructed on that occa¬
sion, that the transaction was a “figure" (Heb.
xi. 19); representing the death and resurrection
of Christ. But our Lord could not have meant
that the revelation then made to Abraham was im¬
parted by Moses to the whole nation of Israel.
It is highly probable, that both Moses himself,
and Abraham, and other eminent and highly fa¬
voured servants of God in those days, received,
more or less, revelations of several things which
they were not commissioned to impart to all the
people.2 And among other things, it is likely
they were taught something concerning the re¬
surrection, and concerning Him who was to pro-
1 This is the exact sense of the original, hy'j.’kXta.trv.T/i, John viii. 56 ; though our version renders it “ rejoiced;” but Abra¬
ham’s joy is what is mentioned afterwards.
2 The eminently pious king, Hezekiah, however, seems to have had no idea, at least at the time when he composed his
hymn, (2 Kings xx.), of any future state.
DISSERTATION THIRD.
cure it. And accordingly we find the very same
Apostle who speaks of the Gospel as “ bringing
in a better hope” than was in the Lavj, speak¬
ing also of some of the Patriarchs as “ looking
for a better country, that is, a heavenly.” (Heb.
xi. 16.)
But when we look to what Moses wrote, by
divine command, for the instruction and guid¬
ance of the Israelites, and as belonging to the
Law—the- dispensation committed to him—we
find him dwelling very fully, and minutely, and
earnestly, on the temporal rewards and temporal
punishments they were to look for ; saying no¬
thing at all about a resurrection and a day of
judgment in the next world.
Many persons however are accustomed, in
speaking of the present subject, to confound to¬
gether two very different questions : (1.) What
was the actual belief of the Jews—or of some
particular Jews—on this or that point? and,
(2.) What was revealed to them in the LAW ?
No unprejudiced reader of that, can think that
Moses designed to teach, therein, the doctrine of
a future state of rewards and punishments as the
sanction of his Law.
On the actual belief, indeed, of the great mass
of the Israelites, we have no means of deciding
positively; but if any one should suppose most of
them to have thought little or nothing, one way
or the other, about what should become of them
after death, nor, consequently, to have either be¬
lieved or disbelieved, properly speaking, the doc¬
trine in question, his conjecture certainly would
not be at variance with the representations Moses
gives of the grossness of ideas, and puerile short¬
sightedness of the nation; who, while fed by a
daily miracle, and promised the especial favour
of the Maker of the universe, had their minds set
on “the flesh-pots of Egypt, and the fish, and the
cucumbers, and the leeks.” Christians of these
days are not surely more gross-minded and un¬
thinking than those Israelites; yet a large propor¬
tion of them require to be incessantly reminded
that this life is not the whole of their existence ;
though the doctrine be one which is expressly
declared in their religion; and silence on that
subject is quite sufficient, if not to eradicate from
475
their minds all belief, at least to put an end to
all thought, about the matter.
There is no doubt, however, that some consi¬
derable time before our Lord’s advent, the belief
in a future state did become prevalent (though,
as the case of the Sadducees proves, not univer¬
sal) among the Jews. In the Second Book of
Maccabees, a work of small authority, indeed, as
a history, but affording sufficient evidence of the
opinions of the writer and his contemporaries, we
find not only unequivocal mention of the doctrine,
(though by the way not as an undisputed point),
but persons represented as actuated by the mo¬
tives which such a doctrine naturally suggests ;
which doubtless we should, sometimes at least,
have met with also in the historical books of the
Old Testament, had the same belief prevailed all
along.
And our Lord himself alludes to the prevail¬
ing opinion of the generality of those whom he
addresses: “Search” (or Ye search1) “the Scrip¬
tures, for in them ye think ye have eternal life,
and they are they that testify of me as much
as to say, the very prophets who allude to the
doctrine of eternal life, do likewise foretell the
coming and describe the character of me, the Be-
stower of it; these two parts of their inspired
word hang together ; he who is blind to the one,
can found no rational hope on the other ; since
“ I am the way, and the truth, and the life;” and
“ he that hath the Son hath life, and he that hath
not the Son, hath not life.” This passage, in¬
deed, as well as the others to the same purpose
in the New Testament, though they imply the
prevalence of this tenet among the Jews, and the
general sincerity and strength of their conviction,
do not at all imply either that this, their con¬
fident expectation, was well-founded on Scrip¬
tural evidence, or that their notions respecting a
future life were correct. Had these last two cir¬
cumstances been superadded (which is evidently
impossible) to the general sincere reception of
the doctrine, it could not have been said with any
propriety, that “ Christ brought life and immor¬
tality to light through the Gospel.”
The truth probably is, that as the indications
of a future state which are to be found in the
1 The word in the original, may hear either an imperative or an indicative sense.
476
PRELIMINARY DISSERTATIONS.
prophets, are mostly such as will admit of an in¬
terpretation referring them to a promise of tem¬
poral deliverance, those persons would most na¬
turally so understand them, in the first instance
at least, who were so “ slow of heart as to the
prophecies respecting the IMessiah, as to expect
in Him a glorious temporal prince only; while
those who were more intelligent, and took in the
spiritual sense of the prophecies relating to Him,
would be led to put the spiritual interpretation
on the other also. We say in the first instance;
because when the belief of a future state had been
introduced, from whatever quarter, and did pre¬
vail, all who held it would naturally interpret in
that sense whatever passages in their Scriptures
seemed to confirm it. But it does not follow that
such a belief was correct, even when supported
by an appeal to passages of Scripture which really
do relate to the doctrine in question; for if one
part of a scheme be understood literally and car¬
nally, and another part spiritually, the result will
be a most erroneous compound ; if eternal life be
understood to be promised, but the character and
kingdom of Christ, who was to bring it to light
and procure it, be misunderstood, the faith thus
formed will be essentially incorrect.
So far, then, as any of the Jews disjoined the
prophetic annunciations of immortality from
those relating to the spiritual kingdom of Christ,
and looked for eternal rewards as earned by obe¬
dience to the Mosaic Law, so far their expecta¬
tions were groundless, their faith erroneous ;
even though resting on the authority of such parts
of Scripture as, in a different sense, do relate to
the doctrine in question.
It is highly probable, however, that the belief
of a future state, as it prevailed among the Jews
in our Lord’s time, and for a considerable period
after, was not, properly speaking, drawn from
their Scriptures, in the first instance;—was not
founded on the few faint hints to be met with in
their prophets, though these were afterwards called
in to support it; but was the gradual result of a
combination of other causes with these imperfect
revelations. For otherwise, one would expect that
there would have been some notice in the Books
of Ezra and Nehemiah (written after all the most
important prophecies had been delivered) of so
mighty a revolution having taken place in the
minds of the Jews of their time, as a change from
ignorance to a full conviction, on so momentous
a point, by a supposed decisive revelation.
Respecting the details of the rise and preva¬
lence of the doctrine of a future state among the
great majority of the Jews, the scantiness of his¬
torical authority leaves us chiefly to our own con¬
jectures. Without entering at large into a dis¬
quisition which must, after all, be obscured by
much uncertainty, it may be allowable to suggest,
that the Jews were likely to be much influenced
by the probable arguments which their own rea¬
son partly supplied, and which they partly learn¬
ed from the neighbouring nations, with whom
(and with some of the more intelligent and en¬
lightened of them) they had much more, and much
more extensive, intercourse after the captivity
than before. Nor does such a supposition mili¬
tate, as might at first sight be suspected, against
what has been elsewhere advanced respecting the
prevailing disbelief, among the heathen, of the
popular fables of Elysium and Tartarus, and re¬
specting the emptiness of the pretended immor¬
tality of the soul, held by philosophers. For what¬
ever their belief might be, they would be likely,
in any discussion with their Jewish neighbours,
to set forth either such arguments as occurred to
them in favour of a future retribution, which un¬
doubtedly was a part of the religion they pro¬
fessed, or such pretended proofs of the natural
and necessary immortality of the soul, as their
schools supplied. And such discussions we can¬
not but suppose must have been frequent; since
the intercourse of the dispersed Jews with the
Gentiles was such as to lead to the disuse of their
own language, and the consequent necessity of a
translation of their Scriptures into Greek. Now
the Jews, who claimed to be favoured with an
authentic revelation of God’s will, and to be his
peculiar People, could not have been satisfied to
rest their pretensions to such superiority, and
their boast of its advantages, on the extraordi¬
nary providence under which their ancestors had
lived, but which seems to have been nearly, if not
entirely, withdrawn from themselves ; but would
be likely to set up a rival claim to that of the
Pagan religions, and to produce from their Scrip¬
tures every thing that might seem to favour the
hope of a future reward. And this, not insin-
DISSERTATION THIRD.
477
cerely; for the very circumstance of the with¬
drawing of that miraculous providence under
which their nation had formerly lived, would lead
them to the expectation of something beyond the
grave to compensate the loss. God’s moral go¬
vernment of their nation, at least, they were as¬
sured of from their own past history; and if He
had formerly been “ a re warder of them that dili¬
gently seek Him,” they would perceive an im¬
probability of his ceasing to be so; though in
this world the “ just recompense of reward” was
evidently no longer to be looked for. It was to be
expected, therefore, that they should be more in¬
clined to believe sincerely in a future retribution
than the Pagans, who had not the same experi¬
mental assurance that the Deity is indeed the
moral Governor and Judge of mankind.
Some, however, make a careless use of those
common words “ know ” and “ believe.” When
discussing questions as to what was “ believed”
by such and such persons, they sometimes speak
as if there were but these two states of mind,—
to believe a certain doctrine, or to disbelieve it;
forgetting, apparently, that belief admits of many
different degrees, from a mere presumption, up
to the most perfect confidence. Yet every one’s
own experience might teach him this. For we
commonly say, “ I believe so and so is the case, but
I am not quite sure'' Some,again, when they
speak of what was “known” to the Pagans, or
to the Jews, seem to forget that the word “know¬
ledge ” implies three things ;—(1.) Confident be¬
lief; (2.) of what is true ; (3.) on sufficient evi¬
dence. For no one could be said to know any
thing that was not true. And again, if any one
had before him one of Euclid’s demonstrations,
he would not be said to know the conclusion,
(though a truth in reality fully proved) if he him¬
self felt at all doubtful about it. And lastly, sup¬
pose two persons were quite positive, the one
that the moon is inhabited, and the other that
it is uninhabited, neither would be said to know
the truth of his opinion ; because, though one or
the other must be, in fact, true, there is no suf¬
ficient proof of either.
It would be unsuitable to our present purpose
—even if space admitted—to examine all the
passages in the Books of Moses which have been
interpreted as relating to a future state ; it may
be needful, however, to say a few words respect¬
ing that one which is cited by our Lord himself
against the Sadducees, in proof of the doctrine :
“ Now, that the dead are raised,” says He, “ even
Moses shewed at the bush, when he saith, £ I
am the God of Abraham, and the God of Isaac,
and the God of Jacob ; He is not the God of the
dead, but of the living; for all live unto Him.’ ”
(Luke xx. 37.)
Now this passage is sometimes misunderstood,
though the meaning of Jesus is sufficiently plain
to an attentive reader of common intelligence.
There was a dispute between two parties, whether
there were or were not to be a resurrection. They
had both of them heard of the doctrine, and had
been accustomed to debate the question. And
He refers them to a passage which, to men so
circumstanced, would afford an argument in fa¬
vour of the doctrine. But Jesus does not say
that Moses designed in this passage to reveal the
doctrine to the unreflecting and gross-minded
people he was instructing ; or that for that pur¬
pose those words were sufficient. No man of com¬
mon sense—much less an inspired lawgiver, such
as Moses—would have entrusted so important a
revelation to one, slight, obscure, and inciden¬
tal hint—so slight that the passage seems to have
quite escaped the notice of the Pharisees when
disputing with the Sadducees on this very point.
Had Moses been commissioned to teach the
Israelites that they were all to rise from the dead,
and to stand before God’s judgment-seat, and be
rewarded or punished in another world, accord¬
ing as they had obeyed or disobeyed the Law he
was delivering, he would not, we may be sure,
have thought it sufficient for this purpose, to re¬
cord the words, “ I am the God of Abraham,
Isaac, and Jacob.” He would, doubtless, have
dwelt on the rewards and punishments of a fu¬
ture state even more copiously and more strongly
than he does on the temporal rewards and punish¬
ments which he does set before them.
For, let it be considered, that as the condition
of the departed is unseen, and as the rewards
and punishments of a future life are not only
comparatively remote, but also must be consi¬
dered as of a nature very different from any
thing we can have experienced; from all these
causes, it is found necessary that the most re-
478
PRELIMINARY DISSERTATIONS.
peated assurances and admonitions should be em¬
ployed, even towards those who have received the
doctrine on the most satisfactory authority. A
Christian minister, accordingly, in these days,
finds that his hearers require to be perpetually
reminded of this truth, to which they have long
since given their assent; and that even, with all
the pains he takes to inculcate it, in every differ¬
ent mode, he is still but very partially successful
in drawing off men’s attention from the things of
this world, and fixing it on the “ unseen things
that are eternal.” Much more must this have
been the case with the Israelites whom Moses was
addressing, who were so dull and gross-minded,
so childishly shortsighted and sensual, that even
the immediate miraculous presence of God among
them, of whose judgments and deliverances they
had been eye-witnesses, was insufficient to keep
them steady in their allegiance to Him. Even
the temporal sanctions of the Law,—the plenty
and famine—the victory and defeat, and all the
other points of that alternative of worldly pros¬
perity and adversity which was set before them
—things in their nature so much more easily com¬
prehended by an unthinking and barbarous peo¬
ple, and so much more suited to their tastes—it
was found necessary to detail with the utmost
minuteness, and to repeat and remind them of in
the most impressive manner, in a vast number of
different passages. (See Exod. xv. 26 ; xx. 12;
xxiii. 20 ;—Lev. xxv. 17; xxvi. 3 ;—Numb. xiv.
20 ; xxxii. 10; xxxiii. 55;—Deut. i. 35 ; iv. 1;
v. 29; vi. 2 ; vii. 12 ; viii. 1; xi. 8 ; xv. 4 ; xvi.
20 ; xvii. 19; xxviii. 1; xxix. 22 ; xxx. 1; xxxi.
16 ; xxxii. 23-43.)
Is not, then, the conclusion inevitable, that if
to such a people the doctrine of future retribution
had been to be revealed, or any traditional
knowledge of it confirmed, we should have found
it still more explicitly stated, and still more fre¬
quently repeated \ And when, instead of any¬
thing like this, we have set before us a few scat¬
tered texts, which, it is contended, allude to or
imply this doctrine, can it be necessary even to
examine whether they are rightly so interpreted \
Surely it is a sufficient reply to say, that if Moses
had intended to inculcate such a doctrine, he
would have clearly stated and dwelt on it in al¬
most every page. Nor is it easy to conceive, how
any man of even ordinary intelligence, and not
blinded by devoted attachment to an hypothesis,
can attentively peruse the Books of the Law,
abounding as they do with such copious descrip¬
tions of the temporal rewards and punishments
(in their own nature so palpable), which sanc¬
tioned that Law, and with such earnest admoni¬
tions grounded on that sanction, and yet can
bring himself seriously to believe, that the doc¬
trine of a state of retribution after death (which,
it cannot be contended, is even mentioned, how¬
ever slightly, in more than a very few passages)
formed a part of the Mosaic revelation.
It deserves to be remarked here how strong
an internal evidence of the truth of what Moses
wrote, is afforded by the fact, that he thus repre¬
sented the sanction of his Law as consisting of
temporal rewards and punishments only.
For had he been a false pretender, he would
have known that he could not secure the constant
fulfilment of his promises and threats. And his
imposture would have been detected, when men
found that they were not regularly rewarded and
punished according as they obeyed or disobeyed
his law. We may be sure, therefore, that a crafty
impostor would not have trusted entirely to pro¬
mises and threats of temporal goods and evils
alone. He would, doubtless, have taught the
Israelites to look for a state of future retribution
also; which was done by the ancient heathen law¬
givers. Most of these, probably, did not them¬
selves believe in what they taught about Elysium
and Tartarus ; but they judged it wise to try to
make their people believe it, for the sake of keep¬
ing them in awe. And they knew that the falsity
of their promises and threats respecting another
world could not be detected by experience.
And Moses, no doubt, would have proceeded in
the same manner, had he been a pretender. But
he was fully convinced that the Israelites really
did live under that miraculous Providence which
he described. And their own experience taught
them that what he said was true. (Deut. iv. 3, 4.)
As for the particulars of all the various instruc¬
tions given to the Israelites, both by Moses and
by the other writers of what is called the Old
Testament, these are to be learned only from a
careful study of those books themselves. Our
DISSERTATION THIRD.
479
present design was merely to give a sketch of the
general character of what is called the Mosaic
Dispensation, especially as to the points wherein,
it differs from other religious systems.
It is to be borne in mind, then—1st, That
it was designed for one People alone, though it
was preparatory to a religion intended for all the
world; and its ordinances accordingly are not at
all binding on us; ‘Idly, It was full of very mi¬
nute directions and regulations, designed, partly
to keep the Israelites separate from the Gentiles,
and faithful to the true God, but partly, by their
hidden typical meaning, to foreshew and prepare
the way for the Gospel revelation; 3dly, It was
a theocracy; a system of direct, special, temporal
government by God’s extraordinary providence.
And accordingly, the sanction of the Mosaic Law
was not the rewards and punishments of a future
state, but temporal blessings and judgments.
These are the points which it is the most im¬
portant to keep clearly and constantly before the
mind; for this reason among others : That mis¬
taken notions on some of these points may en¬
danger a man’s Christian faith, by giving rise to
difficulties and objections much greater, than our
religion—such as it really is—can ever be ex¬
posed to.
Objections there are, indeed, to which no com¬
plete answer can be given, except by shewing
that there are much stronger objections on the
opposite side. But none of the objections to the
Christian revelation, such as it was really given,
are so strong as those brought against what it is
sometimes erroneously represented to be.
Suppose, for instance, any one is taught to be¬
lieve, as a part of his religion, that some portion
of the Mosaic Law is binding on Christians ; al¬
though the persons who teach this are far from
being all of them agreed as to which precepts
are binding, and which not; and although the
Apostle Paul speaks most clearly of the Gentiles
as not being at all “ under the Law ” (Rom. vi.
14), he would find in this a difficulty which is
caused entirely by a misapprehension of Scripture.
Again, suppose a man to have taken up the
notion that temporal blessings and calamities are
now a sign of the Divine favour or displeasure
towards individuals or nations, and that when¬
ever some great calamity occurs, we are at liberty
to declare that such and such a sin has called
down the divine vengeance, this leaves an open¬
ing for objections which can never be got over;
for he sees that bad men often escape such tem¬
poral calamities, while much better men are ex¬
posed to them ; and he knows also that Jesus
Christ and his apostles endured great affliction
in this world, and were rejected by the Jews on
that very ground. So that this doctrine would
make Scripture contradictory both to itself and
to daily experience.
And again, if he is taught that Moses was com¬
missioned to reveal to the Israelites the doctrine
of a resurrection, he will not be able to answer
an infidel who may point out to him how very
imperfectly (at best) the Books of Moses accom¬
plish this purpose; and also, how completely at
variance this is with the declaration that “ Jesus
Christ brought life and immortality to light.”
So that here, again, Scripture will be made to
contradict itself.
All these will be great stumbling-blocks to the
Christian. But when we look to the plain mean¬
ing of the Sacred Books, without attending to the
fanciful theories of uninspired men, all these dif¬
ficulties vanish.
As for the question, what will be the lot, in
another world, of those Jews or Pagans who never
heard of the Gospel, the only answer is, that the
Gospel revelation contains instructions designed
for those who have heard the Gospel, as to what
their duty is, in living according to it themselves,
and doing their best to impart it to others.
As for those whom Providence has shut out
from the knowledge of it, all inquiries respecting
them must be answered as our Lord answered
Peter’s inquiry what was to be the fate of the
Apostle John: “ What is that to thee \ follow
thou me.” (John xxi. 21, 22.)
480
PRELIMINARY DISSERTATIONS.
INTRODUCTION OF THE GOSPEL.
Although the Jews were in eager expectation
at the time when the Lord Jesus appeared, of an
ANOINTED Saviour (Messiah or CHRIST),1
whom the predictions of their prophets had
taught them to expect about that time, they did
not expect Him to introduce anything that could
be called a new religion; but rather to confirm
and extend through the world the Mosaic Law.
And this, it is well known, is what the uncon¬
verted Jews of this day expect.
Yet some of the prophecies relating to the
Christ’s kingdom, do contain allusions to the in¬
troduction of a new religion, distinct from that
taught by Moses. The most decisive of these
prophecies, in relation to this point, is that of
Jeremiah,—“ Behold the days come [are com¬
ing] saith the Lord, that I will make a NEW
COVENANT with the House of Israel * *
* * not according to the covenant that I
made with their fathers,'" &c.
Now the system of divine Laws under which
the Israelites lived, is, in the Books of Moses,
always called (in our version) the “ Covenant”
which the Lord made with them. And in the
Gospels and the Apostolic Epistles, the same word
(in the Greek) is always applied to the Christian
system.
This, however, is likely to escape the notice of
the mere English reader; because, in our ver¬
sion, the very same word Diatheke which, in re¬
ference to the Mosaic Law, is generally rendered
COVENANT, is translated—when it has re¬
ference to the Gospel—by the word TESTA¬
MENT.2 And even in the very passage of Ex¬
odus (xxiv. 8) which is cited in the ninth chap¬
ter of the Epistle to the Hebrews, the very word
which our translators had before rendered “ Co¬
venant f they have changed into “ Testament."
(Heb. ix. 20.) And yet the word is so far from
having different meanings in reference to the
Law and to the Gospel, that, on the contrary,
both the Lord Jesus Himself and his Apostles
most plainly draw a parallel between the two,
and point out the circumstances of the former
Covenants as types and shadows of the Gospel
Dispensation.
In particular, as it was anciently the universal
practice to ratify and sanction every kind of Cove¬
nant by the sacrifice of a victim, the shedding of
whose blood was a necessary ceremony, so this
took place in both cases.
Moses, on the occasion of the establishment of
the LAW, offered a sacrifice, and sprinkled the
blood of the victim on the people ; saying, “ Thi
1 These words signify in the Hebrew and the Greek “ The Anointed,” from the ancient practice of anointing a king, or a
priest, or a prophet, as a part of the ceremony of appointing him to his office.
2 Yet in Gal. iii. 15-19, it is translated Covenant, and what is more remarkable, the very same words in the original are
translated, Heb. viii. 6, “ Mediator of a Covenant,” and in Heb. ix. 15, “ Mediator of a Testament.”
It would be unsuitable in a work of this kind, to enter on the discussion of the interpretation of a disputed text, but it may
be remarked
I. That the passage in Exod. xxiv., which is cited in Heb. ix., ought to have been translated in both by the same English
words.
II. That though we are accustomed to connect the idea of a covenant [compact] with signing and sealing, and not with any
death of a sacrificed victim ; and again, are familiar with the idea of a man’s bequeathing his property by a will, which is to
take effect after his death,—with the Jews it was the reverse. They (as well as many other ancient nations, as may be seen
in many passages of Homer) were accustomed to see every covenant ratified by the blood of a victim. And, on the other
hand, Wills they had none; since the Mosaic Law disposed of a man’s property at his death. Accordingly, no one, in writing
to Hebrews (even though speaking of the Gospel alone), would have been likely to introduce a reference to Wills. But,—
III. The writer is evidently drawing a parallel between the Mosaic Law and the Gospel. Now the Law was not at all of
the nature of a Will [Testament], not being bequeathed by Moses at his death, but fully established forty years before. And
accordingly,
IV. We may observe, that, in the passage before us, the parallel drawn is not between Christ and Moses, but between
Christ and the victim slain by Moses as the ratifier of the Covenant.
To speak of the death of a “ Testator,” therefore, totally destroys the parallel which plainly was in the writer’s mind, and
makes the whole passage unmeaning. But when the death spoken of is understood of the death of the sacrificed victim
even Jesus Christ, who offered Himself to die in our stead, and for our deliverance, the parallel which the writer is dwelling
on becomes intelligible and striking.
DISSERTATION THIRD.
481
is the blood of the Covenant (Exod. xxiv. 8) dience to Him, He prepared them for suffering
[Testament] (Heb. ix. 20) which the Lord hath and death in his cause ; even such as He endured
made with you.” And the Lord Jesus, at the Himself; and pronounced them “ blessed when
Last Supper, when about to offer up Himself as men should hate and persecute” them for His
a sacrifice, says, on giving to the disciples the sake, saying, “ great is your reward in heaven.”
wine which represented his blood, that is, his For, the rewards and punishments which form-
life, This cup is the new Testament [Covenant] ed the sanction of this New Dispensation were
in my blood, which is shed for you.” those of the next world, and those only. Jesus
The word Testament, therefore, whenever it rebuked his disciples for proposing, in their zeal
occurs in Sciipture, is always to be understood for his honour, to call down fire from heaven on
in the sense of “ Covenant" [or “Dispensation”], a village which had rejected Him; as the Prophet
The Christian religion, then, though spring- Elias [Elijah] had been divinely commissioned
ing out of the Mosaic, of which it was the ful- to do, under the old dispensation. (Luke ix. 54.)
filment and completion,1 yet was in itself a new Jesus reproved them, as “not knowing what man-
Religion. It was t\iQ fruit, of which the Mosaic ner of spirit they were of,” He having “ come not
Dispensation was the blossom. And it was as to destroy men’s lives, but to save.”
distinct from it, and in many respects unlike it, But this was not from his regarding a rejection
as a fiuit compared with the blossom which pre- of Him as more pardonable the sins of those
cedes it and pioduces it. who had lived before the days of the Gospel. He
The chief points which distinguish the Chris- taught the reverse of this. For shortly after,
tian Dispensation from the Mosaic, are these when He sent out seventy disciples to preach the
three. 1. Spirituality; 2. Universality ; and, 3. Gospel, He denounced heavier judgments than
Unity. The new kingdom of God was to be “ not what had fallen on sinners of old, against such as
of this world,” but spiritual; it was to be open should reject that Gospel. “ It shall be more to-
to all mankind as its subjects; and it was to lerable," said He, “ for Sodom and Gomorrah”
admit all of them to equal privileges. (which did suffer destruction by fire from heaven)
The former kingdom of God was a kingdom “inthedayof judgment, than for that city.” And
of this world. The Lord was, as has already been while He forewarned his disciples that “ in the
pointed out, not only the God, but the temporal world they would have tribulation,” He promised
Ruler of the Israelites ; prescribing to them not to the faithful Christian “ to raise him up at the
only the religious rites with which He was to be last day,” and to “ prepare a place” for such, in
worshipped, but also the civil regulations under his “ Father’s house.”
which they were to live, and enforcing obedience Thus different was the New Dispensation from
by temporal rewards and penalties. the Old, in respect of the rewards and punish-
Jesus Christ, on the contrary, refused an earthly ments which formed the sanction of each,
kingdom, when attempts were made to force it The IForsAzp also that was required under the
on Him, and declared that “ his kingdom was not Gospel, was of a more spiritual character than
of this world.” He disclaimed all right to inter- that prescribed by the Law.
fere in temporal concerns; saying to one who It is true, the Israelites were commanded to
wished Him to decide between him and his bro- “love the Lord their God, with all their heart,
ther, “ Who made me a judge or a divider over and with all their soul, and with all their
you?” He bid his hearers submit to the civil strength.” But a great part of their service of
government of the Romans, saying, “ Render to Him consisted (as the Apostle Paul expresses it)
Csesar the things that are Caesar’s, and to God the “ in meats and drinks, and carnal ordinances”—
things that are God’s.” And, so far from pro- that is, outward bodily acts; most of which had
mising victory, and long life, and worldly pros- (as has been before observed) an inward hidden
perity, to his followers, as a reward of their obe- signification in reference to the Gospel.
1 “ I am not come,’' says our Lord, “ to destroy the Law and the Prophets, but to fulfil.”
3 p
DISS. III.
482
PRELIMINARY DISSERTATIONS.
Jesus, on the contrary, tells the woman of Sa- Under the Gospel, on the contrary, the reli-
maria, that the time is at hand “ when the true gious rites instituted by Christ himself were
worshippers shall,neither on Mount Gerizim, nor only the Sacraments of Baptism and the Lord’s
at Jerusalem, worship the Fatherbut that they Supper: the one for the admission of members
“shall worship Him in spirit and in truth/5 (John into his Church, and the other to commemorate
iv 23.) What He means by worshipping in truth, his death for man’s redemption, and to represent
and what the Apostle means by saying that “ the our partaking of his Spirit. The one Sacrament
law was given by Moses, but grace and truth came denotes the spiritual Birth of the Christian;
by Jesus Christ” (John i. 17), is, not that the Mo- the other, the continued support of his Spiritual
saic religion was not true, but that its ordinances Life.1
contained the shadow of that of which the Gos- And the signification of these two ordinances
pel contains the substance. The truth of the is much more clearly and fully explained to Chns-
Gospel is not (in reference to the Law) truth as tians in the New Testament Scriptures, than the
opposed to falsehood, but reality, as contrasted signification of the Mosaic ordinances was m the
with shadows and figurative representations. Law. And moreover, the directions given as to
Thus, we read in the Epistle to the Hebrews, the mode of observing these ordinances, are
“ If the blood of bulls and goats, &c., sanctify to much less minute and particular than those given
the purifying of the fie sir (that is, remove cere- by Moses. For instance, there is nothing said
monial impurity, so as to enable a man to attend in Scripture as to the use of leavened or un-
the assemblies of worshippers), “how much more leavened bread at the Lord’s Table or the
shall the blood of Christ purify your conscience posture of the communicants, or the words to be
from dead works.” used, &c. These particulars, and also all other
In the Mosaic religion, the number is very forms and ceremonies for religious worship,
great of what may be not improperly called “ Sa- Jesus left to be regulated in and by each Church
craments.” For a large portion of the very mime- from time to time, with merely the general di-
rous ordinances of the LAW—the various sa- rection from the Apostles, “ Let all things be
orifices, purifyings, and other ceremonial obser- done to edifying.
vances,—were of the nature of what we call Under the LAW, in short, the worship pre-
Sacraments—that is, outward visible signs scribed contained a great number of outward acts,
[figures], divinely appointed, and having an in- striking to the senses, and according to forms
ward meaning connected with religion. The which were precisely laid down; while the in-
worship, in short, of the Israelites, may be con- ward signification of those forms was obscure
sidered as almost made up of Sacraments. and partially hidden. Under the Gospel, on the
But a great part of the inward signification of contrary, the worship prescribed was more spiri-
these Sacraments was hidden from the worship- tual; the external acts (as far as enjoined by
pers; though they were taught that a divine Christ himself) being very few and simple, and
blessing would accompany their observance of without any precise directions as to the forms of
those rites, in pious obedience to the Lord. In them ; while the inward signification of them is
the Passover, for instance, all that they under- plainly made known.
stood as signified in that ordinance, was the And in what relates to moral conduct also,
commemoration of their deliverance from the the precepts given under the New Covenant, are
plague which slew the Egyptians. But the more much less numerous and less precise than those
important part of its signification, the sacrifice of of the LAW. Not that Christians were meant to
the true “ Lamb of God, who taketh away the be less scrupulously careful in leading a virtuous
sin of the world,” was not made known till the life than the Israelites ; but that they are left to
Gospel revelation appeared. regulate their conduct by the PRINCIPLES of
1 John vi. 48-63. See also 1 Cor. xii. 13, where the Apostle gives exactly the above view of the two Sacraments, saying,
“ By one Spirit ye are all baptized into one Body * * * and have been all made to drink into one Spirit.
DISSERTATION THIRD.
483
the Gospel, according to the best of their own
judgment, instead of having a multitude of pre¬
cise precepts laid down for their guidance.
Just as the Christian worship was left to be re¬
gulated as to its FORMS, from time to time, by
each Church, under the general principle of all
“ being done to edifying,” even so Christian
practice was left to be regulated by Christians
themselves, in conformity with GosgeXprinciples,
and the examples set before us by Christ and his
Apostles.
Thus not only does the Gospel require a mo¬
rality in many respects higher and more perfect
in itself than the Law, but it places morality
universally on higher grounds.
Gratitude for the redeeming love of God in
Christ, with mingled veneration and affection for
the person of our great Master, and an exalted
emulation, leading us to tread in his steps,—an
ardent longing to behold his glories and to enjoy
his presence in the world to come,—with an
earnest effort to prepare for that better world,—
love towards our brethren for His sake who died
for us and them,—and, above all, the thought that
the Christian is a part of “ the temple of the
Holy Ghost” who dwelleth in the Church,—even
the Spirit of Christ, “ without which we are none
of His,” a temple which we are bound to keep un¬
defiled ;—these, and such as these, are the sublime
principles of morality, into a conformity with
which the Christian is to fashion his heart and
his life ; and they are such principles as the Mo¬
saic dispensation could not furnish.
The Israelites, as not only living under a re¬
velation which had but a shadow of the good
things of the Gospel, but also as a dull and gross-
minded, and imperfectly civilised people, in a
condition corresponding to that of childhood, were
in few things left to their own moral discretion,
but were furnished with precise rules in most
points of conduct. These answered to the exact
regulations under which children are necessarily
placed, and which are gradually relaxed as they
advance towards maturity ; not by any means on
the ground that good conduct is less required of
men than children ; but that they are expected
to be more capable of regulating their own con¬
duct by their own discretion, and of acting upon
principle.
When, then, the Mosaic code was abolished,
we find no other system of rules substituted in its
place. Our Lord and His Apostles enforced such
duties as were the most liable to be neglected,—•
corrected some prevailing errors,—gave some
particular directions which particular occasions
called for,—but laid dowrn no set of rules for the
conduct of a Christian : they laid down Christian
principles instead; they sought to implant Chris¬
tian dispositions. And this is the more remark¬
able, inasmuch as we may be sure, from the na¬
ture of man, that precise regulations, even though
somewhat tedious to learn, and burdensome to ob¬
serve, would have been highly acceptable to their
converts. Hardly any restraint is so irksome to
man (i.e. to “the natural man”) as to be left to
his own discretion, yet still required to regulate
his conduct according to certain principles, and to
steer his course through the intricate channels of
life, with a constant vigilant exercise of his mo¬
ral judgment. It is much more agreeable to hu¬
man indolence (though at first sight the contrary
might be supposed) to have a complete system of
laws laid down, which are to be observed accord¬
ing to the letter, not to the spirit,—and which,
as long as a man adheres to them, afford both a
consolatory assurance of safety, and an unre¬
strained liberty as to every point not determined
by them,—than to be called upon for incessant
watchfulness,—careful and candid self-examina¬
tion,—and studious cultivation of certain moral
dispositions.
Accordingly, most, if not all systems of man’s
devising (whether corruptions of Christianity, or
built on any other foundation) will be found, even
in what appear their most rigid enactments, to
be accommodated to this tendency of the human
heart. When Mahomet, for instance, enjoined
on his disciples a strict fast during a certain pe¬
riod, and an entire abstinence from wine and
from games of chance, and the devotion of a pre¬
cise portion of their property to the poor, leaving
them at liberty, generally, to follow their own
sensual and worldly inclinations, he imposed a
far less severe task on them, than if he had re¬
quired them constantly to control their appetites
and passions, to repress covetousness, and to be
uniformly temperate, charitable, and heavenly-
minded. And had Paul been (as a false teacher
484
PRELIMINARY DISSERTATIONS.
always will be) disposed to comply with the ex¬
pectations and wishes which his disciples would
naturally form, he would doubtless have referred
them to some part of the Mosaic Law as their
standard of morality, or would have substituted
some other system of rules in its place. Indeed,
there is strong reason to think (especially from
what we find in 1st Corinthians), that something
of this nature had actually been desired of him.
He seems to have been applied to for more pre¬
cise rules than he was willing to give; particu¬
larly as to the lawfulness of going to idol-feasts,
and as to several points relative to marriage and
celibacy; concerning which and other matters,
he gives briefly such directions as the occasion
rendered indispensable, but breaks off into ex¬
hortations to “use this world as not abusing it;”
and speedily recurs to the general description of
the Christian character, and the inculcation of
Christian principles. He will not be induced to
enter into minute details of things forbidden and
permitted,— enjoined and dispensed with; and
even when most occupied in repelling the sus¬
picion that Gospel liberty exempts the Christian
from moral obligation, instead of retaining or
framing anew any system of prohibitions and in¬
junctions, he urges upon his hearers the very
consideration of their being exempt from any such
childish trammels, as a reason for their aiming at
a more perfect holiness of life, on purer and more
generous motives : “ Sin,” he says, “ shall not
have dominion over you ; for ye are not under
the law hut under grace: ” and he perpetually
incites them to walk worthy of their vocation,
on the ground of their being “ bought with a
price,” and bound to “ live unto Him who died
for them;”—“ as risen with Christ” to a new
life of holiness,—exhorted to “ set their affection
on things above, not on things on the earth;”—
as “ living sacrifices” to God;—as “ the temple of
the Holy Ghost,” called upon to keep God’sdwell-
ing-place undefiled, and to abound in all “ the
fruits of the Spirit,” and as “ being delivered
from the Law, that we should serve in newness
of the Spirit, and not in the oldness of the letter.”
He who seeks, then (as many are disposed to
do), either in the Old Testament, or in the New,
for a precise code of laws by which to regulate
his conduct, mistakes the character of our reli¬
gion. It is indeed an error, and a ruinous one,
to think that we may “ continue in sin, because
we are not under the law but under grace ; ” but
it is also an error, and a far commoner one, to
inquire of the Scriptures, in each case that may
occur, what we are strictly bound to do or to ab¬
stain from, and to feel secure as long as we trans¬
gress no distinct commandment. But he who
seeks with sincerity for Christian principles will
not fail to find them. If we endeavour, with the
aid of the Holy Spirit, to trace on our own heart
the delineation of the Christian character which
the Scriptures present, and to conform all our
actions, and words, and thoughts, to that charac¬
ter, our heavenly Teacher will enable us to have
a right judgment in all things, and we shall be
“ led by the Spirit” of Christ to follow his steps,
and to “ purify ourselves even as He is pure;”
that when He shall appear, we may be made like
unto Him, and may behold Him as He is.
Besides Spirituality, another striking feature
of the Christian Dispensation, as contrasted with
the Mosaic, is its UNIVERSALITY. It was to
be unlimited, both in time and in place.1 The
Mosaic Law being only a preparation for the Gos¬
pel, was to come to an end on the establishment
of the new Kingdom of Heaven, which is to con¬
tinue to the end of the world.
And again, the Old Dispensation was designed
for one nation ; the New for all nations. The
“ People of God” was, henceforth, to comprise,
not merely the “ seed of Abraham after the flesh,”
but all mankind, as many as would embrace the
Gospel. “As many as received Him (Jesus Christ),
“ to them gave He power to become the sons of
God.” (John i.) The language of Moses, and of
those who came after him under the Law, was,
“ What nation is there so great, that hath God
so nigh unto them, as the Lord our God is, in all
things that we call upon Him for I” and “ He
hath not dealt so with any nation; neither have
1 Hence the term Catholic (xutloXixri—universal) is applied to the Christian Church—specially in opposition to the Jewish.
It may he remarked, by the way, that the term Roman Catholic does, in strictness of speech, imply a contradiction,—Roman
suggesting a necessary connexion with one place, while Catholic denotes having no necessary connexion with any one place
more than another.
DISSERTATION THIRD.
485
the heathen knowledge of his laws.” The lan¬
guage of Jesus Christ and his Apostles was, “ Go
ye into all the world, and preach the Gospel to
every creature“ Go and teach (make disci¬
ples of) all nations“ There is neither Jew, nor
Greek, barbarian, Scythian, bond, or free.” And
in writing to Gentile believers, the Apostle calls
them (Gal. vi. 16) “the Israel of God;” and says,
“ if ye are Christ’s, then are ye Abraham’s seed,
and heirs according to the promise.” (Gal. iii.
29.)
Hence it was, no doubt, that the Apostles never
applied the term “ Christians”1 to the members
of any church. It was not, of course, that they
were ashamed of it: but they seem to have chosen
not to adopt any new title, but to confine them¬
selves to those which had been applied to God’s
People of old; in order to point out that He had
now admitted Gentiles into the number.
The Israelites had always been called “ breth¬
ren,” being of one race. They are also called a
“ holy” people (“ saints”), as being dedicated to
the Lord; and his “ chosen” [“ elect”] People.
And hence Christians are called “ the brethren,”
the “ elect,” and “ saints,” (ayhi) that is holy, as
being dedicated at baptism to the Lord Jesus.
One necessary circumstance in such a Dispen¬
sation, was, that it should not be like the Mosaic,
a local religion. The Jews, indeed, clung (and
still cling) to the notion that, even when all the
world should be brought to the knowledge of the
true God, still their nation should have a pre¬
eminence; and that the Temple of Jerusalem
should be the great centre of religious worship
for all mankind. And we know there are even
some Christians who expect that Jesus Christ is
to return to this earth in bodily person, and reign
at Jerusalem in great worldly splendour for a
thousand years. But such notions are quite at
variance with the whole character of the Gospel,
as described in our Sacred Books.
The Temple at Jerusalem—“ the place which
the Lord had chosen to cause his NAME to dwell
there,”2 that is, to manifest his presence—was to
be totally and finally destroyed. And Jesus de¬
clared, that “ wheresoever even two or three
should be gathered together in his name, He
would be there in the midst of them.” And
hence, a Christian congregation—not a literal
building—was to be henceforth a portion of the
temple of the MOST HIGH.
“ Know ye not,” says the Apostle Paul, “ that
your bodies are a temple of the Holy Ghost, which
dwelleth in you (1 Cor. vi. 19.)
And as the collective body of worshippers was
called a temple, so the individual Christians are
called “ living stones” of God’s temple. “ Ye
as living stones, are builded together into an holy
temple to the Lord ” (1 Peter ii. 6). Hence arose
the use of the word “ edify,” (oixodo^Tv) literally
“ to build up”—as applied to Christian instruc¬
tion and exhortation.
While Jesus Christ was on earth in bodily per¬
son, HE was the temple of the Lord ; inasmuch
as “ in Him dwelleth all the fulness of the God¬
head bodily” (Col. ii. 9). And accordingly, He
not only speaks expressly “ of the temple of his
body”3 (John ii. 21), but makes several allusions4
(which are often overlooked) to this character of
Himself.
And this, by the way, is a clear proof of his
claiming a divine character. For the Jews un¬
derstood (as He well knew) by “the temple of
the Lord,” not a synagogue,—a place of assembly
for worshippers, but “ the habitation where his
honour (glory) dwelleth.”
And it is worth remarking, that they also un¬
derstood his calling Himself the “ Son of God,”
1 The word Christian (X^artowos) occurs hut three times in the New Testament, Acts xi. 26, xxvi. 28 ; 1 Peter iv. 16 
In no one of these places do we find it applied by Christians themselves to one another. It is mentioned as a name first given
to the disciples at Antioch in Syria, doubtless by the Romans, as the word is of Latin formation. King Agrippa, again,
uses the word in speaking to Paul, and the Apostle Peter introduces it as denoting what was accounted a crime by the
heathen rulers. “ If any man suffer for being a Christian, let him not be ashamed.”
2 There are two words in the original which are both translated “ Temple,” 'isjav, that is, the “ sacred place,” which in¬
cluded the courts of the Temple; and Nao;, (from Nk;&>, “ to dwell,”) the “ House of God,” which was the building in which
sacrifices were offered. For this was the main purpose of a temple ; which was not (like the synagogues, and like our
churches and chapels) a place for religious assemblies.
Naaf is the word used by our Lord when he calls his body a temple, and by Paul, when he applies it to Christians.
iXiyi yri/i) rou vkov rou au/f/.ot.'Tt; uvrou.
4 So the Evangelist—“ The Word became flesh and tabernacled” (tirxiWirt) not merely dwelt, as in our version, “ among us.”
486
PRELIMINARY DISSERTATIONS.
and saying, “ that God was his own proper1
Father,” as a claim to be a divine person. His
words, indeed, might, in themselves, conceivably,
bear another meaning. But He must have known
that they so understood Him. And if they had
mistaken his meaning, He would not have failed
to correct their mistake : else He would have
been bearing false witness against Himself.
They rightly understood Him, therefore, to
be claiming a divine character. And thereupon
they pronounced him guilty of blasphemy (Matt,
xxvi. 65), and liable to death by their Law (Deut.
xviii. 20), as teaching men to worship another
besides the true God.
For they did not expect that the Christ was to
be a divine person; as is plain from their being
unable to solve the question which Jesus put to
them, about David’s calling him LORD (Mark
xii. 37). When therefore, they understood Him to
“make Himself God” (John x. 33), this was so far
from favouring their belief in him as the Christ,
that it convinced them of his being a false pre¬
tender and a blasphemer.
When Jesus departed from the earth, He sent
to his disciples the promised “ Comforter,” to
abide with them for ever ; ” even the Holy Spirit,
whose temple is the whole body of Christians
throughout the world. And every Christian con¬
gregation, as has been already observed, is a por¬
tion of this temple; each individual Christian
being called in Scripture a “ living stone ” of it.
But our Lord takes care to make his disciples
understand that it is not a different Being they
are to look for, and who is to be their new Mas¬
ter ; but a different manifestation of the same
God;—a return of their Master to them under a
new character. For He says expressly, “ I will
not leave you comfortless, I will come unto you:”
—“I will see you again ; and your heart shall re¬
joice ; and your joy no man taketh from you —
“ if any man love me, he will keep my saying, and
my Father will love him; and We will come
unto him, and make our abode with him” And
the like, in several other passages.
And the Apostles, accordingly, speak of “the
LORD (that is, Jesus Christ) being the Spirit
(2 Cor. iii. 17), and assure us that “ if any man
have not the Spirit of Christ, he is none of his.1’
(Rom. viii. 9.)
The same God, then, who to the Israelites, was
made known only as Creator and Governor (God
the Father), was afterwards manifested to Chris¬
tians as being also the Redeemer (God the Son),
and the Sanctifier (God theHoly Ghost): and He
is to be acknowledged by them in this threefold
manifestation, according to our Saviour’s injunc¬
tion to “ baptise in2 the Name of the Father, and
of the Son, and of the Holy Ghost.”
There have been, therefore, in all, three
Temples of the ONE GOD ; first, under the Old
Dispensation, the Temple at Jerusalem; second¬
ly, during the abode on earth of the Lord Jesus,
“ the Temple of his Body;” and, thirdly, (that
which is also often called Christ’s body,) (Eph.
iv. 12,16), the holy Catholic or Universal Church,
comprising all believers throughout the world.
This third and final manifestation of the ONE
GOD plainly belongs to a Dispensation charac¬
terised (as we have said) by UNIVERSALITY.
Another distinguishing feature of the New
Dispensation, was, as has been said, its UNITY
(or Oneness); by which we mean, that it not only
admits all mankind to Christian privileges, but all
of them to equal privileges. “ There is,” as the
Apostle expresses it, “ one Lord, one faith, one
baptism.” “ There is neither Greek, nor Jew,
barbarian, Scythian,bondman,or freeman.” (Eph.
iv. 5, and Col. iii. 11.)
This Christian unity (tvfaris) is often alluded to,
and earnestly dwelt on, by our Sacred writers.
But the passages relating to it are sometimes imr
perfectly understood, or entirely mistaken.
It does not mean agreement in doctrine, nor
yet concord ecndi mutual good-will; though these
are strongly insisted on by the Apostles. But
the unity which they speak of is something dis¬
tinct from these.
Nor, again, does it mean that all Christians
belong, or ought to belong, to some one society
on earth. For this is what the Apostles never
aimed at, and what never was actually the state
of things, from the time that the Christian reli¬
gion extended beyond the city of Jerusalem.
The teaching of Scripture upon this subject,
^ mn'iou. ’thiov. John v. 18.
More properly to or into the Name, tis ro IviftM.
DISSERTATION THIRD.
487
clearly is, that believers on earth are part of a
great society (church or congregation), of which
the Head is in heaven, and of which many of the
members only “ live unto God,” or exist in his
counsels,—some having long since departed, and
some being not yet born. Of such a community
the centre cannot possibly be on earth; and, ac¬
cordingly, the Apostle Paul expressly distin¬
guishes the Christian church [assembly or con¬
gregation] IxxXnria, from that of Israel:—“ Ye
[that is, ye Christians] are not come to the mount
that might be touched; [as the Israelites were
collected in a great assembly (those of them that
ivere alive that day) round Sinai, as a holy place
on earth] .... but ye are come to Mount
Sion, and unto the city of the living God, the hea¬
venly Jerusalem, and to an innumerable company
of angels, to the general assembly and church of
the first-born, which are written in heaven, and
to God the Judge of all, and to the spirits of just
men made perfect, and to Jesus the mediator of
the new covenant” (Heb. xii. 18-24). So, in
the Epistle to the Galatians,—“ Mount Sinai an-
swereth to Jerusalem which now is, and is in
bondage with her children ; but Jerusalem which
is above is free, which is the mother of us all.”
(Gal. iv. 25, 26.)
The Universal Church of Christ may therefore
be said to be ONE in reference to HIM, its su¬
preme Head in heaven ; but it is not one Com¬
munity on earth. And even so the Human race
is one, in respect of the one Creator and Gover¬
nor ; but this does not make it one Family, or
one State.
■ All men, again, ought to live in peace, and to
be kindly disposed towards every fellow-creature.
And all are bound to agree in thinking and do¬
ing whatever is right. But they are not at all
bound to live under one single government, ex¬
tending over the whole World. Nor, again, are all
nations bound to have the same form of govern¬
ment, regal or republican, &c. That is a matter
left to their discretion. But all are bound to do
their best to promote the great objects for which
all government is instituted ;—good order, secu¬
rity of person and property, justice, and public
prosperity.
And even so the Apostles founded Christian
communities, all based on the same principles,
and having the same object in view, but quite
independent of each other, and having no one
common Head on Earth.
The Apostles, indeed, exercised a general go¬
vernment over the various churches which they
founded; but it does not appear that they ap¬
pointed any persons to succeed them in that ge¬
neral government. We read of their appointing
“Elders in every city,” but we do not read of their
setting, or intending to set, any one over the
whole Church.
Any one who looks at the account of Paul’s
taking leave of the Elders of Ephesus and Miletus
(Acts xx.), whom he expected never to see again,
will plainly see that he could not possibly have
had any notion of any supreme central authority,
lodged either in the church of Jerusalem, or of
Rome, or in Peter and his successors, or in any
General Council. For he there directly foretells
that false teachers should arise out of their own
body [that is, from amongst the clergy], and anxi¬
ously impresses on them the best advice he could
think of for guarding against such a danger. Yet
that advice is only to watch, and remember what
he had taught them. This seems to imply that
each particular church was left sufficient means
within itself of ascertaining the true doctrine of
Christ, continuing, and preserving it; but that
the actual preservation of such doctrine depended
on the watchfulness of the churches themselves.
For the occasion was one on which he could not
have failed to bid them have recourse, in case of
any difficulties or disputes among themselves, (such
as he actually foresaw,) to some central Authority,
if any such had existed, or were to be set up.
Nor does the Apostle Peter (though writing his
Second Epistle in the near prospect of death
(2 Pet. i. 14,15), and anxious to provide a record
of his teaching that might last after his decease),
say a word to the disciples of the duty of sub¬
mitting to his successors ; but refers them back
for guidance to the words of the holy prophets,
and the commandments of the apostles, and to
his own letters, and to those of Paul.
In the beginning of the Revelation of John,
too, we find the Lord addressing each of the seven
churches of Asia as severally independent of any
earthly power, and responsible to Him alone for
their conduct as Christian churches.
488
PRELIMINARY DISSERTATIONS.
It is plain, therefore, that the Christian Unity
spoken of in Scripture did not consist in the
placing of all Christians in one Society under one
government on Earth.
It consisted (as we have said) in the admis¬
sion of all men to equal Christian privileges, in¬
stead of having two or more different kinds or
degrees of Christianity, for different classes of
persons.
Now, there did exist something of this kind
under the Mosaic Dispensation. The “ devout
Gentiles” (sometimes called “ Proselytes1 of the
Gate”), were admitted to worship in the outer
court of the Temple, and to frequent the Syna¬
gogues. Those who had embraced the whole
Mosaic Law (who were called “ Proselytes of
righteousness”) were accounted as ranking higher
than the others, and next in holiness to the Israel¬
ites by birth. Then, of the born Israelites, the
Levites were more especially dedicated to the
Lord than those of the other Tribes, and were em¬
ployed in his immediate Service about the Taber¬
nacle, or the Temple. Of the Levites themselves,
again, the family of Aaron were alone admissible
to the priesthood. And lastly, of the Priests
themselves, none except the high priest was per¬
mitted to enter the Holy of Holies,—where he
offered the yearly sacrifice on the great day of
atonement.
And these several gradations, it is to be ob¬
served, are something quite different from the
various degrees of moral worth and piety, or of
intelligence and knowledge, in individuals.
One Israelite (and the like maybe said of Chris¬
tians) might exceed another of the same Tribe and
Family, in pious obedience to the Lord; and a
third might surpass them both. But these dif¬
ferences would not be distinctions introduced by
the Mosaic Religion; but merely those of the in¬
dividual characters of those men. And again, a
pious Israelite, of superior understanding, and of
a reflecting turn of mind, and of more extensive
knowledge than the generality, would have a
clearer, and more intelligent, and more compre¬
hensive view of some parts of the Revelation given
him, and of God’s Providence generally, than an¬
other, equally pious, but of humbler powers and
attainments. And the like must be the case with
Christians also.
But these differences between one man and an¬
other, are such as we find to exist in reference to
all subjects, and do not particularly pertain to
the Mosaic system of Religion ; not being intro¬
duced and created by it.
Those distinctions, on the contrary, which were
noticed just above, are such as did specially belong
to the religion of Moses, and formed a part of the
Dispensation.
The Gospel, on the other hand, admitted of no
such gradations as those established under the
Law.
Various Officers, indeed, were appointed in the
Christian churches ; because no Society can sub¬
sist without them. But all persons, of whatever
Race or Family, were admissible, if properly qua¬
lified, to any Office.
And again, (as was said just above,) men of su¬
perior intelligence and mental cultivation, will
be able, by piously and humbly employing their
powers in the study (among other things) of the
Christian Scriptures, to take a clearer and more
intelligent view of the Gospel revelation, than
those of ordinary abilities and education; pro¬
vided they are careful not to indulge in rash con¬
jectures respecting things beyond human reason,
and which God has not thought fit to reveal.
Such men, if they do use this care, will find
that the more they advance in general cultivation
of mind, the more will the prospect of divine
wisdom and goodness spread around them ; the
horizon, as it were, extending itself in proportion
to their elevation.
But this (as was observed above) is a kind of
distinction between man and man, which was not
introduced by the Gospel, but takes place in all
subjects.
Nor does such a distinction make one man more
a Christian, properly speaking, than another.
In fact, a learned Philosopher would be a worse
Christian than pious men of ordinary ability and
education, if he were content to remain, in point
of religious knowledge, just on a level with these,
while in all other matters he was intellectually
superior to them. He would be like a person
1 tr^owXvrH, one who comes over to some religion or religious sect.
DISSERTATION THIRD.
489
offering as the tithe of an increased produce, the
same absolute amount as would be a fair propor¬
tion from a smaller or less fertile field.
And in respect of piety of sentiment, also, and
purity of conduct, one man may be a better Chris¬
tian than another, that is, he may make a better
use of his Christian privileges. But the Gospel
itself does not exclude any man from any Chris¬
tian privileges to which it admits others.
This is .one of the points wherein (as has been
said) it differs from the Mosaic Law.
And this feature of the Gospel was one which
proved a great stumbling-block to the Jews.
They could not easily reconcile themselves to the
thought of Gentiles being placed completely on
a level with them. And they clung to the idea
that the Jews by Race must continue to be in an
especial manner God’s peculiar People, even when
both they and the Gentiles should have become
subjects of Christ’s kingdom. And even among
the Gentile Christians themselves, there seems to
have been a tendency to consider the different
“ spiritual [miraculous] gifts” bestowed on differ¬
ent persons, as dividing Christians into so many
distinct Orders. This tendency we find the
Apostle Paul earnestly contending against in se¬
veral parts of his writings; especially in 1 Cor. xii.
The miraculous gifts were bestowed not for the
benefit of the possessor, but of the Church. And
they did not either prove the possessor to be pe¬
culiarly acceptable to God, or necessarily make
him so. For Judas Iscariot, who afterwards be¬
trayed his Master, had been endowed, along with
the other Apostles, with miraculous powers. And
our Lord declares that He will say, at the Day
of Judgment, to some who should boast of having,
in his Name, £: done many mighty works,” “ I
know you not; depart from me, all ye workers of
iniquity.”
Yet in all ages of the Church, there has been
a tendency, more or less, to draw some unwar¬
ranted distinctions between ordinary Christians,
and those to whom the name of Saints has been
confined, either from their having been inspired,
like the Evangelists and Apostles, or from their
being supposed to possess some extraordinary
personal holiness, beyond what is expected of
Christians generally.
The Apostles, on the contrary, (as was ob-
DISS. in.
served above,) call all Christians “ Saintsas
being all dedicated to Christ in Baptism, and all
admitted to be equal partakers (as far as relates
to their own holiness of character, and power of
becoming acceptable to God) of his sanctifying
Spirit. There is no hint given that a less degree
of personal holiness will suffice for us, than for
an Apostle; and Peter, or Paul, however supe¬
rior to us in their miraculous gifts, yet called
themselves Saints in reference not to any thing
peculiar to them, but to what was common to
them with us.
Nevertheless, one may find persons, even now,
who seem to regard Christianity as not, in reality,
one religion, but two; one, for persons of pre¬
eminent holiness, or who are admitted to certain
superior Christian privileges, beyond the gene¬
rality ; and the other for the multitude; who are
to believe implicitly whatever the most eminent
Saints think fit to impart, and to do whatever
they bid them.
But nothing can be more at variance than such
a notion is with the whole character of the Gos¬
pel Dispensation. For this was designed as a re¬
velation to men of all classes, in every tolerably-
civilised country. And the endeavour of the
Apostles was to “ make known the mystery of
the Gospel” to all, in proportion as they were
able and willing to receive it. And they la¬
boured, by assiduous instruction and exhortation,
to make men, more and more, thus able and will-
ing. They urged them to “ grow in grace and
in the knowledge of the Lord Jesus Christ.”
And they reckoned themselves to be ‘£ pure from
the blood of all men,” only inasmuch as they ££ had
not shunned to declare to them all the counsel
of God.”
When we look back to these distinguishing
points in the Gospel Dispensation which have
been here noticed—its Spirituality, Universali¬
ty, and Unity—as well as to several other re¬
markable features of it, we cannot but perceive
what a strong confirmation they afford of its di¬
vine origin.
It was altogether the most unlikely thing to
have occurred to the mind of any man, whether
dreaming enthusiast or crafty impostor. And of
all men, Jews were the most unlikely to have
3 Q
490
PRELIMINARY DISSERTATIONS.
imagined anything of the kind. Indeed, the great
stumbling-block to the Jews was its being so
utterly at variance (as has been remarked above)
with all their most deeply-rooted prejudices, and
all their long-cherished hopes.
But it was almost equally at variance with many
of the notions of the Heathen also. And these
latter had nearly as much difficulty in receiving
a religion from Jews—a people generally de¬
spised by them—as the J ews had, in acknow¬
ledging the “Gentiles” as fellow-heirs with them¬
selves. And both parties—Jews and Gentiles—
had never conceived an idea of such a thing as a
religion without any literal Temple, without an
A Itar, without Sacrifices, and without any Sacri¬
ficing Priest on earth.
Such a Religion could never have been in¬
vented, in those days, by any man, Jew or Gen¬
tile; and could never have been established
throughout the chief part of the civilised World,
except by the overpowering force of miraculous
proofs.
ESTABLISHMENT OE
When the bodily presence of our Divine Mas¬
ter was withdrawn from the earth, his Apostles
proceeded, according to his directions, to establish
“ the kingdom of heaven,” over which He had
placed them, saying, “ I appoint unto you a king¬
dom, as my Father hath appointed unto me.”
For, that Gospel which had been proclaimed
by Himself and his disciples, during his personal
ministry, was, that “ the kingdom of heaven was
at hand.” That kingdom was then only in prepa¬
ration. It was not completely begun, till the
Apostles, after the outpouring on them of the
Holy Spirit, on the day of Pentecost, founded at
Jerusalem the first Christian church, and bap¬
tized into the Name of the Lord Jesus about three
thousand persons, who were thus enrolled as sub¬
jects of that kingdom.
The number of these in Jerusalem increased
rapidly. Other churches were established in
Judea, in Galilee, in Samaria, and elsewhere.
And a few years after, the apostles having learnt
by an express revelation—quite contrary to their
own expectations—that Gentiles were to be ad¬
mitted, on equal terms, as subjects of Christ’s
kingdom, great numbers of churches, consisting
chiefly of these, arose in various parts of the
world.
Although, however, mention is made in Scrip¬
ture of several of these churches, we have only
incidental, slight, and scanty accounts of the way
CHRIST’S KINGDOM.
in which the Apostles proceeded in founding them.
Very few particulars are given of the regulations
established,—of the appointment of the several
Orders of Ministers,—of the Divine Service cele¬
brated,—or, in short, of any of the details of mat¬
ters pertaining to a Christian church.
One reason for this, probably, was, that a Jewish
Synagogue, or a collection of Synagogues in the
same neighbourhood, became at once a Christian
Church, as soon as the worshippers, or a consi¬
derable portion of them, had embraced the Gos¬
pel, and had separated themselves from unbe¬
lievers. They had only to make such additions to
their public Service, and such alterations, as were
required by their reception of the Gospel; leav¬
ing everything else as it was. For, the Apostles,
we know, acted on the rule of “becoming all
things to all men that is, of complying with
men’s habits, and avoiding all shock to their feel¬
ings, as far as this could be done without any
sacrifice of principle, or detriment to the great
objects proposed. It is incredible, therefore,
especially considering that for several years the
only converts were persons frequenting the syna¬
gogues,—Jews or devout Gentiles,—that they
should have utterly disregarded all the existing an d
long-reverenced Institutions and Offices, which
could so easily be accommodated to the New Dis¬
pensation. To have established everything on
a perfectly new system, through mere love of
DISSERTATION THIRD.
491
novelty,—to have erected, as it were, a fresh
building from the very ground, when there was
one standing which with small and easy altera¬
tions would answer all the same purposes, would
have been to raise up, wantonly, difficulties and
obstacles to their own success. They did not
indeed, no doubt, think themselves bound or au¬
thorised, to adhere blindly to existing institutions
in any points in which these were at variance
with the .spirit of the Gospel, or were capable of
being changed for the better : and doubtless they
introduced from time to time, (and designed that
their successors should do the same,) such altera¬
tions in the functions of the several officers, and
in all regulations respecting other non-essential
points, as circumstances of time and place might
require. But we cannot suppose that they aimed
at originality for its own sake, or altered for the
sake of altering. And the correspondence, ac¬
cordingly, which has been traced by learned men
between the Synagogue and the Church, is no
more than what we might antecedently have ex¬
pected.
The attempt to effect this conversion of a
Jewish synagogue into a Christian church, seems
always to have been made, in the first instance,
in every place where there was an opening for it.
Even after the call of the idolatrous Gentiles, it
appears plainly to have been the practice of the
Apostles Paul and Barnabas, when they came to
any city in which there was a synagogue, to go
thither first and deliver their sacred message to
the Jews, and “devout (or proselyte) Gentiles;”—
according to their own expression (Acts xiii. 16);
to the “ men of Israel,” and those “ that feared
God f—adding, that “it was necessary that the
word of God should first be preached to them.”
And when they founded a church in any of
those cities in which (and such were probably a
very large majority) there was no Jewish Syna¬
gogue that received the Gospel, it is likely they
would still conform in a great measure to the
same model.
Now, Jewish synagogues, and all things per*
taining to them, were so familiarly known in the
days of our sacred writers, that there was no need
to enter into any minute particulars respecting
the officers, regulations, and practices of a syna¬
gogue.
Nevertheless, it seems probable that we should
have found in Scripture something more than we
do find, of incidental notices of some of these par¬
ticulars, if there had not been some especial rea¬
son for omitting them.
The same may be said with respect to the
Creeds, Catechisms, and Forms of Prayer, and of
administering the Sacraments, which were in use
in the days of the Apostles. We have no record
in Scripture of any of these. And yet the more
we reflect on the subject, viewing not merely the
abstract probabilities of the case, but also what
has actually occurred in respect of other religions,
the more strongly we shall feel that the first foun¬
ders of a religion might naturally have been ex¬
pected to have transmitted to posterity some, more
or less systematic, compositions, such as we have
been speaking of.
For if we look, for instance, to the Koran, we
find Mahomet, in the midst of much extraneous
matter, fitted only to gratify the appetite for the
marvellous, inserting, however, also, not only a
precise description of the Mahometan Faith, but
likewise minute directions concerning Fasts,
Prayers, Ablutions,—the amount of Alms,—and
all other points of the Mussulman’s service of
God. The same is represented to be the character
of the Hindoo Shaster, and other Pagan books
professing to contain a divine revelation of any
system of religion.
And that there is nothing in the Christian reli¬
gion, considered in itself, that stands in the way
of such a procedure, is plain from the number of
works of this description which have appeared
from the earliest times, (after the age of inspira¬
tion^) 1 down to the present;—from the writings
entitled the “ Apostles’ Creed,” and the “ Apos-
1 A proof, it should be observed, is thus afforded, that the New Testament Books are no forgery of the early Christians,
since these would have been sure to insert what we do find in their own acknowledged writings, and which is altogether
wanting in the Sacred Books.
The same inference may be drawn from a fact which we have already spoken of, the entire absence in the New Testament
of the title of Christians, as applied by themselves to each other. It seems to have been adopted by Christians very early ;
probably soon after the destruction of Jerusalem; and if the Books of the New Testament had been forged or interpolated by
them, at that, or at any subsequent period, there can be no doubt we should have found it frequently so employed therein.
492
PRELIMINARY DISSERTATIONS.
tolical Constitutions,” &c. (compositions of uncer¬
tain authors, and amidst the variety of opinions
respecting them, never regarded as Scripture),
down to the modern Formularies and Confessions
of Faith.
Nor, again, can it be said that there was any¬
thing in the founders of the religion, any more
than in the religion itself, which, humanly speak¬
ing, should seem likely to preclude them from
transmitting to us such compositions. On the
contrary, the Apostles were brought up Jews;
accustomed, in their earliest notions of religion,
to refer to the Books of the Law, as containing
precise statements of their belief, and most mi¬
nute directions as to religious worship and cere¬
monies. So that, to give complete and regular
instructions as to the character and the requisi¬
tions of the new religion, as it would have been
natural for any one, was more especially to be
expected of these men.
And even supposing that the other avocations
of the Apostles would not allow any of them lei¬
sure for such compositions,—though we know that
some of them did find time for writing, two of
them not a little,—even this supposition does not
at all explain the difficulty; for the Acts and two
of the Gospels were written by men who were
only attendants on the Apostles. Nor would such
writings as we are speaking of have required an
inspired penman ; only one who had access to
persons thus gifted. We know with what care
the Apostolic Epistles were preserved, first by the
churches to which they were respectively sent, and
afterwards, by the others also, as soon as they re¬
ceived copies. How comes it, then, that no one of
the Elders (Presbyters) of any of these Churches
should have written down, and afterwards sub¬
mitted to the revision of an Apostle, that outline
of catechetical instruction—that elementary in¬
troduction to the Christian faith—which they
must have received at first from that Apostle’s
lips, and have afterwards employed in the instruc¬
tion of their own converts \ Why did none of them
record any of the prayers, of which they must
have heard so many, from an Apostle’s mouth,
both in the ordinary devotional assemblies, in the
administration of the Sacraments, and in the
“ laying on of hands,” by which they themselves
had been ordained.
Paul, after having given the most general ex¬
hortations to the Corinthians for the preservation
of decent regularity in their religious meetings,
adds, “the rest will I set in order when I come.”
And so, doubtless, he did; and so he must have
done, by verbaldirections, in all the other churches
also: is it not strange then, that these verbal di¬
rections should nowhere have been committed to
writing 1
This would have seemed a most obvious and
effectual mode of precluding all future disorders
and disputes; as also the drawing up of a com¬
pendious statement of Christian doctrines, would
have seemed a safeguard against the still more
important evil of heretical error. Yet if any such
statements and formularies had been drawn up,
with the sanction, and under the revision of an
Apostle, we may be sure they would have been
preserved and transmitted to posterity, with the
most scrupulous and reverential care. The con¬
clusion therefore seems inevitable, that either no
one of the numerous Elders and Catechists ever
thought of doing this, or else that they were for¬
bidden by the Apostles to execute any such de¬
sign : and each of these alternatives seems alike
inexplicable by natural causes.
For it should be remembered that, when other
points are equal, it is much more difficult to ex¬
plain a negative than & positive circumstance in
our Scriptures. There is something, suppose, in
the New Testament, which the first promulga¬
tors of Christianity—considered as mere unas¬
sisted men—were not likely to write ; and there
is something else which they were, we will sup¬
pose, equally unlikely to omit writing; now, these
two difficulties are far from equal. For with
respect to the former, if we can make out that
any one of these men might have been, by nature
or by circumstances, qualified and induced to un¬
dertake the work, the phenomenon is solved. To
point out even a single individual able and likely
to write it, would account for its being written.
But it is not so with respect to the other case,
that of omission. Here we have to prove a nega¬
tive ;—to show, not merely that this or that man
was likely not to write what we find omitted, but
that wo one was likely to write it. Suppose we
could make out the possibility or probability
of Paul’s having left no Creed, Catechism, or
DISSERTATION THIRD.
493
Canons, why have we none from the pen of Luke,
or of Mark ? Suppose this also explained, why did
not John or Peter supply the deficiency? And
why, again, did none of the numerous Bishops
and Presbyters whom they ordained, undertake
the work, under their direction ? The difficulty,
therefore, in this case exceeds the other, cceteris
paribus, more than a hundredfold.
Since, then, no one of the first promulgators
of Christianity did that which they must—some
of them at least—have been naturally led to do,
it follows that they must have been supernatu-
rally withheld from it; how little soever we may
be able even to conjecture the object of the prohi¬
bition. Form respect of this, and several other
(humanly speaking, unaccountable) circumstances
in our religion, it is important to observe, that
the argument thence derivable in favour of the
divine origin of Christianity, does not turn on the
supposed wisdom of this or that appointment,
which we conceive to be worthy of the Deity,
and thence infer that the religion must have pro¬
ceeded from Him; but on the utter improbabi¬
lity of its having proceeded from Man ; which
leaves its divine origin the only alternative. The
Christian Scriptures considered in this point
of view, present to us a standing Miracle ; at
least, a Monument of a Miracle; since they are in
several points such as we may be sure, accord¬
ing to all natural causes, they would not have
been. Even though the character which these
writings do in fact exhibit, be such as we can¬
not clearly account for on any hypothesis, still,
if they are such as we can clearly perceive no
false pretenders would have composed, the evi¬
dence is complete, though the difficulty may re¬
main unexplained.
Although, however, we cannot pretend, in every
case, to perceive the reasons for what God has ap¬
pointed, it is not in the present case difficult to
discern the superhuman wisdom of the course
adopted. If the Hymns1 and forms of Prayer,
—the Catechisms,—the Confessions of faith,—
and the Ecclesiastical regulations, which the
Apostles employed, had been recorded, these
would have all been regarded as parts of Scrip¬
ture : and even had they been accompanied by
the most express declarations of the lawfulness
of altering or laying aside any of them, we can¬
not doubt that they would have been in practice
most scrupulously retained, even when changes
of manners, tastes, and local and temporary cir¬
cumstances of every kind, rendered them no
longer the most suitable. The Jewish ritual, de¬
signed for one Nation and Country, and intended
to be of temporary duration, was fixed and accu¬
rately prescribed. The same Divine Wisdom from
which both dispensations proceeded, having de¬
signed Christianity for all Nations and Ages, left
Christians at large in respect of those points in
which variation might be desirable. But we think
no human wisdom would have foreseen and pro¬
vided for this. That a number of Jews, accus¬
tomed from their infancy to so strict a ritual,
should, in introducing Christianity as the second
part of the same Dispensation, have abstained not
only from accurately prescribing for the use of all
Christian Churches for ever, the mode of divine
worship, but even from recording what was ac¬
tually in use under their own directions, does
seem utterly incredible, unless we suppose them
to have been restrained from doing this by a
special admonition of the Divine Spirit.
And we may be sure, as we have said, that if
they had recorded the particulars of their own
worship, the very words they wrote would have
been invested in our minds with so much sanctity,
that it would have been thought presumptuous to
vary or to omit them, however inappropriate they
might have become. The Lord’s Prayer, the
only one of general application that is recorded
in the Scriptures, though so framed as to be suit¬
able in all Ages and Countries, has yet been sub¬
jected to much superstitious abuse. A supersti¬
tious Christian mutters his “ paternosters,” as a
kind of sacred charm, on all occasions, however
inappropriate.
In like manner, the Apostles’ Creed, from its
acknowledged antiquity, together with the title
it bears, and the tradition (probably, in part,
Pliny’s account of the early Christians, derived in part from those who had belonged to the Society, mentions that they
recited “ a hymn to Christ, as to a God.” This ancient hymn has not been transmitted to us, so as to be recognised. It is
not unlikely, however, that it, or some part of it, formed the basis of that which we call the Te Deum.
494
PRELIMINARY DISSERTATIONS.
true1) of its being the composition of the Apos¬
tles, is held by many Christians in a kind of
veneration which may justly be characterised as
superstitious. There are persons of the lower
orders, and some above the very lowest, who are
accustomed to recite it in their private devotions
as a prayer.
No doubt there must ever be danger of all prayer
degenerating into a superstitious formalism; but
this danger must evidently be increased in pro¬
portion as the words uttered are the less appro¬
priate to the occasion, and to the circumstances of
the petitioner; and this must inevitably have been
more likely to take place with a Liturgy trans¬
mitted to us from the times of the Apostles, as
a part of Scripture.
Withrespectto Catechisms again,—elementary
introductions to the Christian faith,—nearly the
same reasons will hold good. For though the
Christian religion is fundamentally “ the same
yesterday, and to-day, and for ever,” it is impos¬
sible that any one mode of introducing its truths
to the mind of the catechumen, can be the best
adapted for children andadults,—the civilized and
the barbarian,—and for all the other varieties of
station, sex, country, intellectual culture, and
natural capacity.
Each church, therefore, was left, through the
wise foresight of Him who alone “ knew what is
in Man,” to provide for its own wants as they
should arise;—to steer its own course by the Chart
and Compass which his holy Word supplies, regu¬
lating for itself the Sails and Rudder, according to
the winds and currents it may meet with.2 “ The
Apostles had begun and established precedents,
which, of course, would be naturally adopted by
their uninspired successors. But still, as these
were only the formal means of grace, and not
the blessing itself, it was equally to be expected
that the church should assume a discretionary
power, whenever the means established became
impracticable or clearlyunsuitable, and either sub¬
stitute others, or even altogether abolish such as
existed  It might seem at first that the
apostolical precedents were literally binding on
all Ages ; but this cannot have been intended;
and for this reason, that the greater portion of
the apostolical practices have been transmitted to
us, not on apostolical authority, but on the au¬
thority of the uninspired church ; which has
handed them down with an uncertain mixture of
its own appointments. How are we to know the
enactments of the inspired rulers from those of
the uninspired \ and if there be no certain clue,
we must either bring down the authority of apos¬
tolical usage to that of the uninspired church,
or raise that of the uninspired church to that of
the apostolical. Now, the former is, doubtless,
what was, to a certain extent, intended by the
Apostles themselves ; as will appear from a line
of distinction by which they have carefully par¬
titioned off such of their appointments as are de¬
signed to be perpetual, from such as are left to
share the possibility of change, with the institu¬
tions of uninspired wisdom.
If, then, wre look to the account of the Christian
usages contained in Scripture, nothing can be
more unquestionable than that, while some are
specified, others are passed over in silence. It
is not even left so as to make us imagine that
those mentioned may be all: but, while some are
noted specifically, the establishment of others is
implied, without the particular mode of obser¬
vance being given. Thus, we are all equally sure
from Scripture, that Christian ministers were or¬
dained by a certain form, and that Christians as¬
sembled in prayer ; but while the precise process
of laying on of hands is mentioned in the former
institution, no account is given of the precise
method of Church-Service, or even of any regular
forms of prayer, beyond the Lord’s Prayer. Even
the record of the Ordination Service itself admits
of the same distinction. It is quite as certain,
that, in it, some prayer was used, as that some
outward form accompanied the prayer ; but the
form is specified, the prayer left unrecorded.
What, now, is the obvious interpretation of the
holy Dispenser’s meaning in this mode of record 1
Clearly, it is, that the Apostles regulated, under
his guidance, the forms and practices of the
Mf, as there seems good reason for thinking, part of this creed was actually in use with the Apostles, this circumstance
fenders it the more remarkable that it should not have been recorded by them in their writings.—See King’s (afterwards
Lord King) History of the Apostles'1 Greed.
2 Bishop Hind’s History of the Rise and Progress of Christianity.
DISSERTATION THIRD.
495
Church, so as was best calculated to convey grace
to the Church at that time. Nevertheless, part of
its institutions were of a nature, which, although
formal, would never require a change ; and these,
therefore, were left recorded in the Scriptures, to
mark this distinction of character. The others
were not, indeed, to be capriciously abandoned,
nor except when there should be manifest cause
for so doing; but as such a case was supposable,
these were left to mingle with the uninspired pre¬
cedents, the claims of which as precedents would
be increased by this uncertain admixture, and the
authority of the whole rendered so far binding,
and so far subject to the discretion of the church.
They might not be altered, unless sufficient
grounds should appear ; but the settling of this
point, was left to the discretion of the church.”1
The Apostles themselves, however, and their
numerous fellow-labourers, would not, probably,
have been, if left to themselves, so far-sighted as
to perceive (all, and each of them, without a single
exception) the expediency of this procedure.
Most likely, many of them,—but according to all
human probability, some of them,—would have
left us, as parts of Scripture, compositions such as
we have been speaking of; and these, there can
be no doubt, would have been scrupulously re¬
tained for ever. They would have left us Cate¬
chisms, which would have been like precise direc¬
tions for the cultivation of some plant, admirably
adapted to a particular soil and climate, but inap¬
plicable to those of a contrary description. Their
Symbols would have stood like ancient sea-walls,
built to repel the encroachments of thewiwes, and
still scrupulously kept in repair, when perhaps the
sea had retired from them many miles, and was
encroaching on some different part of the coast.
There are multitudes, even as it is, who do not,
even now, perceive the expediency of the omis¬
sion ; there are not a few who even complain of
it as a defect, or even make it a ground of objec¬
tion. That, in that day, the reasons for the pro¬
cedure actually adopted, should have occurred,
and occurred to all the first Christians, supposing
them mere unassisted men, and men, too, brought
up in Judaism, is utterly incredible.
But besides the reason we have now been
speaking of, there is another, perhaps not less
important, against the providing in Scripture of
a regular systematic statement of Christian doc¬
trines. Supposing such a summary of Gospel
truths had been drawn up, and could have been
contrived with such exquisite skill as to be suffi¬
cient and well adapted for all, of every Age and
Country, what Avould have been the probable re¬
sult 1 It would have commanded the unhesitating
assent of all Christians; who would, with deep
veneration, have stored up the very words of it
in their memory, without any need of laboriously
searching the rest of the Scriptures, to ascertain
its agreement with them; which is what we do
(at least are evidently called on to do) with a
human exposition of the faith : and the absence
of this labour, together with the tranquil security
as to the correctness of their belief which would
have been thus generated, would have ended in
a careless and contented apathy. There would
have been no room for doubt,—no call for vigilant
attention in the investigation of truth,—none of
that effort of mind which is now requisite, in
comparing one passage with another, and collect¬
ing instruction from the scattered, oblique, and
incidental references to various doctrines in the
existing Scriptures; and in consequence none of
that excitement of the best feelings, and that im¬
provement of the heart, which are the natural,
and doubtless the designed result of an humble,
diligent, and sincere study of the Christian Scrip¬
tures.
In fact, all study, properly so called, of the rest
of Scripture,—all lively interest in its perusal,—
would have been nearly superseded by such an
inspired compendium of doctrine; to which alone,
as far the most convenient for that purpose, ha¬
bitual reference would have been made in any
questions that might arise. Both would have
been regarded, indeed, as of divine authority;
but the Compendium, as the fused and purified
metal: the other, as the mine containing the crude
ore. And the Compendium itself, being not like
the existing Scriptures, that from which the faith
is to be learned, but the very thing to he learned.
Bishop Hind’s History of the Rise and Progress of Christianity, vol. ii., p. 113-115.
49 G
PRELIMINARY DISSERTATIONS.
would have come to be regarded by most with an
indolent, unthinking veneration, which would
have exercised little or no influence on the cha¬
racter.
Their orthodoxy would have been, as it were,
petrified, like the bodies of those animals we read
of incrusted in the ice of the polar regions ; firm-
fixed, indeed, and preserved unchangeable, but
cold, motionless, lifeless.
It is only when our energies are roused, and
our faculties exercised, and our attention kept
awake, by an ardent pursuit of truth, and anxi¬
ous watchfulness against error,—when, in short,
we feel ourselves to be doing something towards
acquiring, or retaining, or improving our know¬
ledge,—it is then only, that that knowledge makes
the requisite practical impression on the heart
and on the conduct.
To the Church, then, has her all-wise Founder
left the office of teaching, to the Scriptures, that
oi proving, the Christian doctrines : to the Scrip¬
tures He has left the delineation of Christian prin¬
ciples ; to each Church, the application of those
principles, in their Symbols, or Articles of Reli¬
gion,—in their Forms of Worship,—and in their
Ecclesiastical regulations.
And there can be no doubt that every Chris¬
tian is bound, in duty to his divine Master, to
pay obedience to the enactments and ordinances
—not adverse to Scripture—of the Church he be¬
longs to, though consisting of uninspired men.
For such a measure of obedience is indispensably
necessary for the existence of any SOCIETY.
And it is certain that it is the will of the Lord
Jesus that his People should be members of
those Christian Societies called Churches 
The religion He introduced was manifestly de¬
signed by Him—and so understood by His im¬
mediate followers—to be a social religion. It
was not merely a revelation of certain truths to
be received, and of practical rules to be observed,
—it was not a mere system of doctrines and pre¬
cepts to be embraced by each individual, inde¬
pendently of others; and in which his agreement
or co-operation with any others would be acci¬
dental ; as when several men have come to the
same conclusion in some science, or have adopted
the same system of agriculture or of medicine ;
but it was to be a combination of men who should
be “ members of the body of Christ,”—“ living
stones” of one spiritual temple ; “ edifying” (i. e.
building up) “ one another in their faith,”—and
“ brethren” of one holy family.
Of this design to establish what should be em¬
phatically a social religion,—a “ fellowship” or
“ communion (i. e. community) of saints,” there
can be, we should think, no doubt in the mind
of any reflecting reader of our Sacred Books. Be¬
sides our Lord’s general promise of “ coming unto
and dwelling in any man who should love Him,
and keep his saying,” there is a distinct promise
also of an especial presence in any assembly—
even “ of two or three—gathered together in his
name.” Besides the general promises made to
prayer,—to the prayer of an individual “ in the
closet,”—there is a distinct promise also to those
who shall “ agree together, touching something
they shall ask.” And it is in conformity with his
own institutions that Christians have, ever since,
celebrated what they designate as, emphatically,
the Communion, by meeting together, “ to break
bread,” in commemoration of his redemption of
his people.
His design, in short, manifestly was to adapt
his religion to the social principles of man’s na¬
ture ; to bind his disciples, throughout all ages,
to each other, by those ties of mutual attachment,
sympathy, and co-operation, which in every hu¬
man community and association, of whatever
kind, are found so powerful.
And it is evident that whoever directs or sanc¬
tions tlm establishment of a Community, must be
understood as thereby sanctioning those institu¬
tions which belong to the essence of a Community.
Now there are three things which necessarily
pertain to every Community or Society, and are
implied by its existence; 1st, Officers; 2dly,
Rules; and, 3dly, the power of admitting or ex¬
cluding Members.
I. Whatever may be the character and objects
of any Society—whether it be a political Society
[or State,]—or a scientific,—or a mercantile,—or
a religious society, such as we call a Church,—in
all cases, it must have some kind of Government,
and consequently, certain Officers to administer
that Government; to manage the affairs of the
Body, and to exercise some control over the in¬
dividual members of it.
DISSERTATION THIRD.
497
II. There must also be, in every society, some
kind of Rules ; whether called Laws, or Statutes,
or Canons, or by whatever other name: and these
rules must be enforced by some kind of Penal¬
ties against violations of them.
III. And there must also exist, somewhere, a
power of determining who shall be members oi the
Society;—what persons shall be admitted or re¬
fused admittance into it, or expelled, or restored.
These three things are, as we have said, essen¬
tial to every kind of Society.
As for a Civil Community [or State,] that is not
a voluntary society; but must have, from the very
nature of the case, a coercive power: it is neces¬
sary that all persons residing in each Country,
should be compelled to submit to the government
of that country. And there is no limit, except
in the justice and wisdom of the rulers, to the
punishments denounced against those who dis¬
obey the laws.
But in a voluntary Society, (such as Christ de¬
signed a Church to be,) the ultimate penalty must
be expulsion, all others short of this being sub¬
mitted to as the alternative. “ If he refuse,” says
our Lord, “ to hear the Church; let him be unto
thee as a heathen man,”—that is, no longer a
member of that church.1
And even as a “heathen man,”—one who never
belonged to our Society,—has no claim to any of
its privileges, nor is subject to its government,
or liable .to its penalties ; so, if one who has been
a member of it, has renounced its authority, or
has been formally expelled from it, he is placed
on the same footing. It would be unfair, on the
one hand, for him to claim any of its advantages,
or, on the other hand, for us to attempt to subject
him to its laws and its penalties. He, and that
particular Society, have thenceforth nothing to
do with each other.2
And here it should be observed that it is ne¬
cessary not only that every Community should
have laws, enforced by certain penalties, but also
that it should have power to make laws, from
time to time, not in opposition to the fundamen¬
tal principles of the society, but for the carrying
out of those principles.
For it would be impossible to lay down rules,
once for all, so minute and precise as to meet
every possible case, and never to need any addi¬
tion. Even the Mosaic law, which was extremely
particular in its directions, was not sufficient
without some enactments, made by competent
authority, to decide, for instance, what was or was
not to be accounted work, and consequently pro¬
hibited on the Sabbath-day; and many other
such points of detail.
Our Lord does indeed censure the Jewish
rulers for having, in some points, made absurd
and frivolous regulations : and in some, having
“ made the word of God of none effect, through
their tradition.” In the one caser, they had made
an ill use of the power intrusted to them ; in the
other they had altogether exceeded their power.
Butnevertheless, He acknowledges that the power
did exist in the rulers of the Jewish Church, and
that obedience was due to it when their enact¬
ments were not at variance with God’s laws.
“ The scribes and Pharisees’1 said He, sit in
Moses’ seatthat is, they are his successors in
the office of making and enforcing regulations for
the Jewish church ; “ whatsoever they hid you
observe and do, so do ye ; but do ye not after
their works ; for they say, and do not.”
Now the rules laid down in Scripture for a
Christian Church, are (as was remarked above)
far less numerous and less precise than those of
the Law. So that it was even much more neces¬
sary that a Christian Church should have that
1 That is, of that particular church whose authority he has renounced. It does not follow that he may not be a member
of some other church.
Indeed, it has often happened, amidst the many unhappy dissensions among Christians, that all the members of a church
that is completely opposed to another, are shut out from Christian inter-communion with the other church.
But though we may be justified in saying, such and such a person is not, and cannot be, considered a member of this par¬
ticular church, we have no right to pronounce him thereupon excluded from the Universal Church of Christ.
2 Sometimes it has happened that some church, though claiming no power over a “ heathen man,” has yet called in what
is termed the “ secular arm,” to punish as heretics, persons who have renounced allegiance to that church, or whom it has ex¬
communicated. But this is in manifest opposition to what our Lord says in the passage above referred to, as well as to
his declaration that his “ kingdom is not of this world.”
Whether those persons were justly or unjustly excommunicated,—or whether they were right or wrong in seceding,—the
church which has renounced them, or which they have renounced, has clearly no more rights over them, according to our
Lord’s express declaration, than it has over a “ heathen man.”
DISS. III. ' 3 R
498
PRELIMINARY DISSERTATIONS.
power which, our Lord himself acknowledged to
have been possessed by the Scribes and Pharisees.
And since it was undoubtedly his design that
there should always be Christian churches “even
to the end of the world,” there can be no doubt
that He intended these churches to possess all
those three requisites above mentioned, without
which no community of any kind can subsist. And
hence, we may feel assured that the officers of
Christian churches, and the rules established in
them, (when not adverse to Gospel principles),
and the penalties which form the sanction of those
rules, and the power which every church exer¬
cises of admitting or excluding persons as mem¬
bers,—all these, must, we are sure, have the sanc¬
tion of our divine Master Himself.
All this we might infer, as has been said, from
the mere fact of his having sanctioned the for¬
mation of Christian communities. But, besides
this, He expressly conferred on his Apostles—•
the first founders and first rulers of Christian
churches—those very powers just mentioned.
The power of “ binding and loosing111—that is,
of making and annulling decisions and regula¬
tions—He distinctly conferred on the Apostles ;
declaring that their decisions should be bound
“ in heaven,” that is sanctioned by Himself.
(Matt. xvi. 19.)
This declaration He made first to Peter, as
being the person chosen to take the lead in lay¬
ing the first foundation of a Christian church ;
both among the Jews on the day of Pentecost,
and afterwards among the Gentiles. (Actsii.,x.)
But subsequently, a little before his departure,
He appoints a kingdom to the Apostles generally.
(Luke xxii. 29.) In addressing Peter, He men¬
tions the “ keys of the kingdom of heaven,” that
is the power of admitting members into the Chris¬
tian church, and of excluding them. But this is
in fact included in the appointment to the king¬
dom ; since the rulers of a church must be intrusted
with this power.
And He also expressly conferred on the Apostles
the power of inflicting and remitting church
penalties (John xx. 23), for offences against the
society,—what we call Ecclesiastical offences.
And it is likely, that, besides this, his words had
reference also to their office of preaching “ bap¬
tism for remission of sins,” and of administering
or refusing baptism, according as each person
might appear in their judgment fit or unfit: that
is, the qualifications for being admitted into
Christ’s kingdom, and for being allowed to con¬
tinue a subject of it, having been laid down by
Himself as the Supreme Head, his ministers were
left to decide in each case, who was, or was not,
thus qualified.
This, doubtless, was our Lord’s meaning when
He spoke of the “keys of the kingdom of heaven.11
And it is probably one part of what He meant to
include in the power of remitting and retaining
sins.
But this, at least, is quite certain, that no mere
man can have power to forgive sins as against
GOD; or to grant or refuse admission into the
realms of heavenly bliss; which is the office of
the Lord Jesus Himself at the Day of Judgment.
By Him his disciples were merely authorised to
admit men into his kingdom on earth,—that is,
his Church: and to pronounce not what particu¬
lar individuals, but what kind of persons should
have remission of sins against God, and should
attain eternal life,—namely, those whose peni¬
tence and faith are seen by Him to be sincere.
He might, had He seen fit, have gifted his
apostles and other ministers with the faculty of
reading any man’s heart, and foreseeing the fu¬
ture course of his life; and He might thus have
enabled them to pronounce positively of an indi¬
vidual, that his sins were pardoned by the MOST
High, and that he would inherit eternal life.
But this gift our Lord did not think fit to bestow
on his Apostles, or on any man. They were left,
to judge, as they could, of the sincerity of each
man’s professions, and of the steadfastness both
of his faith, and of his whole Christian character.
And in this they were liable to be deceived; as
is evident from the case (among others) of Simon
the sorcerer (Acts viii.) ; for he would not have
been admitted to baptism, if it had been per¬
ceived at the time that he was “ in the bond of
iniquity.”
1 This is the phrase which was and still continues in use among the Jews in that sense.
DISSERTATION THIRD.
499
But offences against a society, that society has
a right to pardon; just as an individual may for¬
give sins against himself. Indeed, our Lord, we
know, commanded us thus to forgive. But of
course He did not mean that we have power to
pardon sins as against God. For that belongs to
Him alone. If any one does some wrong to us,
or to a Society, he also, by doing this wrong, sins
against God. It rests with us, or with the so¬
ciety he has wronged, to pardon the wrong as
against his fellow-men. But God alone can par¬
don the sin against God.
All those three requisites, then, which we have
been speaking of as essential to every Society, our
Lord expressly established. He appointed offi¬
cers, and He conferred the power of enacting
rules, and of admitting and excluding members.
And it is plain that what He said to those par¬
ticular disciples He was addressing, could not be
meant as limited to them alone, but as having
reference to His Church “ even unto the end of
the world;” since it is certain He designed his
Church not to cease with the lives of its first
founders, but to continue permanently.
We may, perhaps, think that, if matters had
been left to our judgment and disposal, we should
have asked for a continuance of miracles for the
conversion of unbelievers, and a continued inspi¬
ration in the church, in order to be sure of an
infallible interpretation of Scripture. But as
there is no promise of anything of this kind, we
have no right either to conclude from our own
wishes, that it must exist; or again, to reject
Christianity for not completely answering our
wishes. It is quite otherwise, however, with
those things we have been speaking of as essen¬
tial requisitesfor a Society. Weinfer that achris-
tian church must have them, not because this is
advantageous and desirable, but because it is in¬
dispensable to every kind of Society. Without
Officers and Rules of some kind or other, and power
of enrolling and excluding Members, no society
could subsist at all. And since our Great Master
did sanction the existence of Christian societies,
we fairly conclude, that by so doing, He sanc¬
tioned whatever is essential to the existence of a
society, and implied thereby.
Such was manifestly the will of the divine
Founder of our religion. And it was also his will
that Christian communities, the several portions
of his kingdom, should continue to subsist un¬
der the government of uninspired fallible men,
having no miraculous powers, nor any infallible
guide on earth to appeal to, in case of any doubt
as to the right interpretation of Scripture, or the
right application of scripture principles.
This may seem to some persons very strange.
Not but that we can perceive plainly that there
is a difference between our case and that of those
who lived when the Gospel was first proclaimed.
For in order to introduce a revelation from Hea¬
ven, it was indispensably necessary that certain
persons should receive from Heaven a communi¬
cation of what that revelation was. And no one
could have been expected to listen to them, if
they had not proved, by the display of miraculous
powers, that they really had received such a com¬
munication. In after times, on the contrary,
the writings of those persons may be referred to
for a knowledge of what the religion is. And
the miracles by which they established it, and
without which it never could have been estab¬
lished, may be appealed to in proof of its divine
origin.
But still, if it were left to each Christian’s judg¬
ment and choice, whether he would or would not
have inspiration and other miraculous gifts be¬
stowed on the Church, for the conversion of un¬
believers, and for the satisfaction of the doubting,
and for the correction of such errors as arise from
time to time,—if each man were left to decide on
this according to his own judgment and wishes—
it is probable that very many would ask for a re¬
storation of those gifts. We should not at least
find all Christians agreeing to decline them as no
longer needed.
Many there are who would fain have—some¬
where at least on earth—an infallible guide, ac¬
cessible to all men, to decide, by evident divine
authority, on any questions that may arise. And
some there are who are even so bent on this, that
they resolve to find it, because they deem it need¬
ful, with, or without good reasons for believing
it to exist; and who will accept the Gospel on no
other condition.
The truth is, that there is in the human mind
a craving for infallibility, which predisposes men
towards the pretensions, either of a supposed un-
500
PRELIMINARY DISSERTATIONS.
erring church, or of those who claim or who pro¬
mise immediate inspiration. And accordingly,
we find persons sometimes waver for a time be¬
tween these two classes of pretensions, and ulti¬
mately give in totheone, or to theothe^and some¬
times thus changing more than once, yet still
always clinging to the confident expectation of
finding that infallibility we have been speaking of.
They are inquiring only after a way of exempting
themselves from all further inquiry. Their care
is only to relieve themselves ultimately from all
further need of vigilant care. They are navigat¬
ing in search of a perfectly safe haven, in which
the helm may be abandoned, and the vessel left
to ride securely, without any need of watching the
winds and currents, and of looking out for rocks
and shoals. They hope to obtain, in all ages of
the church, that exemption from all need of vigi¬
lant circumspection, which was not granted even
in the age of the Apostles; since we find that, even
when there. these infallible guides on earth,
Christians are perpetually warned of the danger
of mistaking “false apostles” for genuine.
And it may be added, that any one who is thus
induced to give himself up implicitly to the guid¬
ance of such a Supposed infallible authority, with¬
out presuming thenceforth to exercise his own
judgment on any point relative to religion, or to
think for himself at all on such matters,—such a
one will be likely to regard this procedure as the
very perfection of pious humility,—as a most
reverent observance of the rule of “ lean not to
thine own understandingthough, in reality, it
is the very error of leaning improperly to our own
understanding. For to resolve to believe that
God must have dealt with mankind just in the
way that we could wish as the most desirable,
and in the way that to us seems the most pro¬
bable ; this is in fact to set up ourselves as his
judges. It is to dictate to Him in the spirit of
Naaman, who thought that the prophet would re¬
cover him by a touch, and who chose to be healed
by the waters of Abana and Pharpar, the rivers
of Damascus, which he deemed better than all the
waters of Israel.
But any thing that falls in at once with men’s
wishes, and with their conjectures, and which also
presents itself to them in the guise of a virtuous
humility ; this, they are often found readily and
firmly to believe, not only without evidence, but
against all evidence. And thus it is in the pre¬
sent case. The principle of which we have been
speaking,—that every revelation from heaven ne-
cessarilyrequires, as an indispensable accompani¬
ment, an infallible interpreter always at hand,—
this principle clings so strongly to the minds of
many men, that they are even found still to main¬
tain it, after they have ceased to believe in any
revelation at all, or even in the existence of a
God.
There can be, we conceive, no doubt of the fact,
that very great numbers of men are to be found,—
they are much more numerous in some parts of
the Continent than among us;—men not deficient
in intelligence, nor altogether strangers to reflec¬
tion, who, while they for the most part conform
externally to the prevailing r'eligion, are inwardly
utter unbelievers in Christianity; yet still hold
to the principle,—which, in fact, has had the
chief share in making them unbelievers,—that
the idea of a Divine Revelation implies that
of a universally-accessible Infallible Inter-
PRETER ; and that the one, without the other, is
an absurdity and contradiction.
We have said that it is this principle that
has mainly contributed to make these men unbe¬
lievers. For when a tolerably intelligent and re¬
flective man has fully satisfied himself, that, in
point of fact, no such provision has been made,—
that no infallible and universally-accessible in¬
terpreter does exist on earth—yet still adheres
to the principle of its supposed necessity, the
consequence is inevitable, that he will at once
reject all belief of Christianity. The ideas of a
Revelation, and of an unerring Interpre¬
ter, being in his mind inseparably conjoined,
the overthrow of the one belief cannot but carry
the other along with it. Such a person, there¬
fore, will be apt to think it not worth Avhile to
examine the reasons in favour of any other sys¬
tem of Christianity not pretending to furnish an
infallible interpreter. This—which, he is fully
convinced, is essential to a revelation from Hea¬
ven—is by some churches claimed, but not esta¬
blished, while the rest do not even claim it. The
pretensions of the one he has listened to and de¬
liberately rejected ; those of the other he regards
as not even worth listening to.
DISSERTATION THIRD.
501
The system, then, of reasoning from our own
conjectures as to the necessity of the Most High
doing so and so, tends to lead a man to proceed
from the rejection of his own form of Christianity,
to a rejection of revelation altogether. But does
it stop here ? Does not the same system lead na¬
turally to Atheism also 1 Experience shows that
that consequence, which reason might have anti¬
cipated, does often actually take place. He who
gives the reins to his own conjectures as to what
is necessary, and thence draws his conclusions,
will be likely to find a necessity for such divine
interference in the affairs of the world as does not
in fact take place. He-will deem it no less than
necessary, that an omnipotent, and all-wise, and
beneficent Being should interfere to rescue the
oppressed from the oppressor,—the corrupted
from the. corrupter,1—to deliver men from such
temptations to evil as- it is morally impossible
they should withstand ;—and, in short, to banish
mZ.from the universe. And, since this is not
done, he draws the inference that there cannot
possibly be a God, and that to believe otherwise
is a gross absurdity. Such a belief he may, in¬
deed, consider as useful for keeping up a whole¬
some awe. in the minds of the vulgar; and for
their sakes he may outwardly profess Christianity
also ; even as the heathen philosophers of old en¬
deavoured to keep up the popular superstitions :
but a real belief he will regard as something im¬
possible to an intelligent and reflective mind.
We are very far from saying that all, or the
greater part, of those who maintain the principle
we are speaking of, are Atheists. We all know
how common it is for men to fail of carrying out
some principle (whether good or bad) which they
have adopted ;—how common, to maintain the
premises, and not perceive the conclusion to which
they lead. But the tendency of the principle it¬
self is what we are speaking of: and the danger
is anything but imaginary of its leading, in fact
as it does naturally and consistently, to Atheism
as its ultimate result.
But whatever our wishes or conjectures might
have been, no such choice,—no such offer of infal¬
lible guidance—has been set before us. What is
required of us is, thankfully to endeavour to make
the best use of the advantages we have, instead
of conjecturing or wondering why it is that we
have not more. We are not called on to ex¬
plain to the satisfaction of all men, or of ourselves,
the reasons, in each instance, for God’s having
dealt with us as He has. What we are to say, in
reference to any such inquiries, is, “ Even so,
Father ! for so it seemed good in Thy sight."
To Him, then, it seemed good, that after the
departure of the Apostles, no successors to them
in the Apostolic office should arise. As members
indeed, and as ministers and rulers of Christian
churches, they were succeeded by others, down to
this day. But as Apostles of Jesus Christ, they
have no successors. As personal attendants on
Him, and eye-witnesses of his resurrection—as
both possessors and dispensers of miraculous
gifts (Acts viii. 14), and as inspired oracles to
make known the divine will,—in all these points,
which were what constituted the apostolic office,
they left none to succeed them. In all that re¬
lates to Christian churches, and also in that for
the sake of which churches were instituted, the
conduct of individual Christians in all the con¬
cerns of life,—men are now, by the decree of Pro¬
vidence, left to act (according to their own best
discretion) in conformity with Gospel principles,
as recorded in Scripture.
The Holy Spirit, indeed, “ who helpeth our
infirmities,” is promised to those who earnestly
seek it, and who strive to profit by it. This aid
is needed by us, and is promised to us, both for
the establishment of our faith, and also for the
guidance of our judgment, and of our conduct,
whether in matters connected with the Church,
or in anything else. But how far any one is really
“ led by the Spirit” in each instance, there is no
authority on earth to decide. It is the office of
that Spirit to guard us both from error and from
sin. But we must not pretend to be either free
from sin, or exempt from error; since of that we
cannot be infallible judges. If it be right to say,
“ Who can tell how oft he offendeth ?” we ought
to add also, “Who can tell how oft he mistaketh'?”
A Christian church, then, being a Society, in¬
stituted under Christ’s sanction, for the purpose
of keeping up and extending the knowledge and
practice of his religion, and of thus making men
faithful and obedient subjects of his kingdom,
the rulers of such a Society are bound to act, ac¬
cording to the best of their power, with a view
502
PRELIMINARY DISSERTATIONS.
to this object. They are to keep in mind, that
is, that it is Christ's kingdom and not their own,
in which they hold office. “ We preach not our¬
selves,” says the Apostle, “but Christ Jesus our
Lord; and us, your servants for Christ’s sake.”
The powers, therefore, which He has entrusted
to a Church are to be exercised in strict confor¬
mity with the principles laid down by Him and
his inspired servants.
No Church has power to alter, or to add to, the
terms of gospel salvation as laid down in Scrip¬
ture ; or to keep back from its members anything
revealed in Scripture; or to encourage, or will¬
ingly leave them, in ignorance of it. For its very
office is, in the words of Christ Himself, to “teach
them to observe all things whatsoever I have
commanded.”
It is, indeed, allowable, and proper, that a
Church should employ, for the instruction of its
people, convenient Summaries and Expositions
of Scripture doctrine, such, for instance, as Cate¬
chisms. For this is to supply an omission, which
(as above observed) was purposely left in Scripture.
But then these Catechisms, &c., must contain
the very doctrines of Scripture, and none other.
And being the compositions of uninspired men, no
authority must be claimed for them, except from
their agreement with Scripture. And the same
rule applies to Forms of prayer and to Creeds.
Creeds, which have been sometimes called
“ Symbols,” sometimes “ Confessions of Faith,”
or “ Articles of Religion,” are statements of such
doctrines as must be acknowledged by any one
who would become, or remain, a member of the
Church which adopts that Creed. In different
Churches, in the earliest times, different Creeds
were in use ; and alterations were made in them
from time to time. Not that any Church had a
right to alter the Christian Faith ; but that it
was necessary to meet, and guard against the par¬
ticular religiouserrors which arose in various Ages
and Countries. But as none of these creeds is to
be found in Scripture, so, there is none that can
claim any authority, except from its conformity
to Scripture.
The doctrines, then, which a Christian Church
teaches, and is bound to teach, are to be those of
the Christian Scriptures; neither more nor less.
But on the other hand, Church ordinances and
regulations are only required to be not at vari¬
ance with Scripture. For it is indispensably ne¬
cessary for a Church to make enactments on many
points respecting which nothing is precisely laid
down in Scripture; but only the general princi¬
ple, “ let all things be done to edifying.”
For instance, assembling for public joint Wor¬
ship is enjoined in Scripture; but the times, places
and mode of conducting the worship are not spe¬
cified. The Sacraments, again, as instituted by
Christ, are to be celebrated; but the mode of cele¬
bration is not prescribed. It is not even ordered
that the Elders [Clergy] are to administer the Sa¬
craments ; though this, (very naturally and pro¬
perly,) has been the rule of every Church.
In these, and in several other points, a Church
is not only authorized, but compelled, to make
regulations ; because we are enjoined to do things
which must be done in some regular specified
mode, and the mode is not laid down in Scripture.
For instance, since Christians are commanded
(as has just been observed) to assemble (Heb.
x. 25) for divine worship, it is necessary that the
times for doing so should be fixed by authority.
And, accordingly, certain days have been in all
ages of Christianity, set apart by every Church,
for this purpose. Thus every one knows what is
called Christmas-day has been set apart to com¬
memorate the birth of Jesus Christ; the day
called Good Friday, for his crucifixion ; and Eas-
ter-day in each year, and also the first day in
each week (thence called “ the Lord’s Hay”), to
celebrate his resurrection.1
,, 1 H®nce> the Sunday, being (like the Jewish Sabbath) one day in every seven, is sometimes called the Christian Sabbath;
though kept on a different day of the week from the Jewish Sabbath, and in a different manner, and to commemorate a dif¬
ferent event.
Neither the fourth Commandment, nor any other law enjoining the observance of the seventh day of the week in memory
of the close of the creation, is regarded by Christians as binding on them. For if it were, they would be bound strictly to
obey it, as it was given. For the Apostles,—who, themselves, as Jews, kept the Sabbath-day, and also, as Christians, assembled
for worship on the Lord s Day,—never made a change of the Sabbath from the seventh day to the first. And no Church, con¬
sisting of uninspired men, has any right to change any divine ordinance designed for them. But the Mosaic Law having
come to an end, and, moreover, having never been binding on Gentiles, a Christian church is left to determine what days shall
be set apart, as above mentioned.
DISSERTATION THIRD. 503
And in the observance of “ the Lord’s Day,”
after the example of the Apostles, (though no
express command of theirs to that effect is re¬
corded), all Churches, from the earliest times,
have, very properly, agreed.
A Church that should act otherwise, would be
making an ill use of the powers bestowed on it;
but it would be presumptuously exceeding its
powers, if it should dare to enact anything at va¬
riance with Scripture. For instance, either, on
the one hand, to abolish the Sacraments ordained
by Christ, or, on the other hand, to depart from
that celebration of the Lord’s Supper which He
Himself appointed, and to administer the bread
without the cup, which He directed all the Dis¬
ciples to drink of, is Avhat no Church can have
any right to do.
And it would be equally against Scripture,
and that in a most important point, to attempt
to convert Christian Ministers into sacrificing
Priests: because Scripture plainly teaches that,
under the Gospel, this office belongs to Christ
alone.
But Christian Ministers for the performance of
such duties as are described in Paul’s Epistles
to Timothy and to Titus, and elsewhere, every
church clearly has a right to appoint, for the rea¬
sons already given. And there is no reason to
doubt that the Eldprs ordained in each Church
by Paul, or any other Apostle, did themselves, in
turn, ordain others to assist or to succeed them ;
and these again, others; and so on in perpe¬
tuity, doAvn to the present day.
But then, it is from the Church that Ministers
(as well as Church ordinances) derive all their
authority. Whether in sending fresh labourers
into the Lord’s vineyard, or in any of their other
functions, they must act as authorised by the
Society, and as representing it; not as possessing
independent powers, as individuals. For it is to
a Church as to a Society that those rights we have
been speaking of belong; and whatever is done
by the regular Officers of a Society, conformably
to its constitution, is to be considered as done by
the society.
When, therefore, Bishops, or any others, are
spoken of as ordaining persons to the Ministry,
it must be understood that, being empowered by
their Church so to do, according to the rules of
that Church, they are its representatives, and
their acts are its acts.
And if any Minister were regularly deprived
of his office, he would no longer have any power
either to ordain, or in any way to officiate; un¬
less he were admitted into some other Church,
and taken into its service as one of its Ministers.
The rights, then, conferred on Christian Com¬
munities by our divine Master Himself, being
such as we have described, no one need be dis¬
tressed by doubts and fears respecting some pos¬
sible irregularity in the ordination of some mini¬
ster, which may possibly have occurred at some
time or other, in the course of eighteen centuries.
Amidst the wars and tumults and general con¬
fusion which took place at various times during
that space, and especially during what are called
“ the dark ages,” when ignorance and barbarism,
as well as lawless violence, were so prevalent, it
may have happened, more than once, that some
person who had never been regularly ordained, or,
perhaps, even baptized, may have contrived to
intrude himself into the ministerial office; and
to have even attained the rank of a bishop ; and
may thus have been the ordainer of others, the
successors of whom may possibly be among our¬
selves at this day.
I here is no Christian Minister now existing
that can trace up, with complete certainty, his
own ordination, through perfectly regular steps, to
the times of the Apostles. And, accordingly, if
the reality of the ministerial Office were made to
depend, not on a man’s being an acknowledged
Minister of a Christian Church, but on a certain
mysterious sacramental virtue, transmitted from
hand to hand, in unbroken succession from the
Apostles, there would be a most distressing and
incurable uncertainty in each Christian’s mind,
whether he were really baptized, really ordained,
or really partaker of any Christian privileges.
But as it is, there is no ground for any such
perplexing doubts. A Christian Community,
formed on Gospel principles, confers on its recog¬
nised Officers the rights of Christian Ministers;
who are to be regarded as having Christ’s com¬
mission, and as successors of the Apostles in the
ministerial office. We are bound, indeed, to do
our very best to prevent irregularities of any
kind, in ordinations, and in every thing else con-
504
PRELIMINARY DISSERTATIONS.
nected with our religion. But we need not fear
that any accidental or unavoidable irregularity
that may ever have occurred, can have the effect
of shutting out whole Bodies of sincere disciples
from the Gospel covenant and Christian ordi¬
nances, or from any privilege granted by Christ
Himself to those who should be “ gathered to¬
gether in his name.”
It is to be observed, however, that although no
one individual Christian Minister can, with com¬
plete certainty, trace his own succession in an
unbroken chain from the Apostles, and prove that
there was no flaw in any link, the case is differ¬
ent when we look to the Clergy generally. For
there can be no reasonable doubt that such an
Order of men did always exist, from the times of
the Apostles, continuously, to this day. We may
be as sure of this as we are that great numbers
of the English nation are descendants of the
Saxons, who settled in Britain in the fifth and
sixth centuries, though there is probably no one
man who could trace his descent from any of
them. For, Christian Ministers held office in the
churches as immediate successors of others who
held the same office, and who in like manner pro¬
fessed to be the immediate successors of others,
&c., whose predecessors had been appointed by
the Apostles themselves.
Now if, a century ago, or ten centuries ago, or
at any other time, a number of men had arisen,
claiming to be the immediate successors (as above
described) of persons holding this office, when,
in fact, no such Order of men had ever heenheard
of, such an absurd pretension would have been
immediately exposed and derided.
There must always, therefore, have existed
such an Order of men, from the time of those
Apostles who professed to be eye-witnesses of the
Resurrection, and to work sensible public miracles
in proof of their divine commission. And, con¬
sequently, the Christian Ministry is a standing
monument to attest the public proclamation of
those miraculous events at the very time when
they are said to have occurred.
Now, at that time there must have been great
numbers of persons able and willing to expose
the imposture, had there been any.
And this argument for the truth of the Sacred
History is quite independent of any particular
mode of appointing Christian Ministers. If, for
instance, these had always been elected by the
People, and had at once entered on their office
without any ordination by other Ministers, still,
if they were but appointed (in whatever mode)
as immediate successors of persons holding the
same office, the argument would be the same.
That mode, indeed, of admitting men into the
Ministry which was practised by the Apostles
(1 Tim. iv. 14, and v. 22) has, in fact, been retained
in all ages of Christianity. But the argument we
have now Been considering is quite independent
of this. It turns entirely on the mere fact of
the constant existence of a certain Order of men.
And it is worth observing, that the Lord’s
Day is a monument of the same kind. It is kept
all over the world, by different and even hostile
Bodies of Christians, in memory of the Resurrec¬
tion of Jesus Christ. And not only so,—for this
alone would not be a decisive proof,—but it is
observed by them as a day which has been always
thus kept, from the very day when the Lord
Jesus is recorded to have risen, apd to have ap¬
peared to his Disciples. Now, if it had not been
thus constantly kept, from the first, but the ob¬
servance of it introduced in some later age, those
among whom it was thus introduced would have
been able to testify that they had never heard of
such a festival before.
DISSERTATION THIRD.
505
CORRUPTIONS OF CHRISTIANITY.
It was observed in the preceding Section, that
if all things relating to the Christian Church had
been ordered by Divine Providence in the way
that men would have been likely to conjecture as
the most probable, and to wish for as the most
desirable, there would have been some infallible
guide left on Earth, to decide all questions that
might arise, and to guard us against all possible
religious erroi*. There would have been a, per¬
petual inspiration lodged in some person or
persons, indued with such manifest miraculous
powers as could leave no doubt as to their inspi¬
ration. And these infallible interpreters would
have been universally and readily accessible.
But it is notorious, that such was not the de¬
sign of Providence : and that no such guide does
exist. Of all the persons who have claimed infal-
libity, there is none who has displayed (as Paul
did) “ the signs of an apostle,” that is, such
palpable and undeniable miraculous powers, as to
leave no doubt in any candid mind, of his being
really inspired. And since the very purpose for
which an infallible guide is supposed to be need¬
ed, is, the removal of all reasonable doubts, it is
plain that if God had thought fit to provide us
with such a guide, He would not have left it at
all doubtful where we were to look for that guide.
It seems to have been his design that part of
Man’s trial on Earth should consist in his being
required to “ prove (Aojc/^a^g/v), [that is, try and
examine] all things, and hold fast that which is
right.” We are called on to inquire carefully,
and humbly, and piously, after truth ; and to em¬
brace whatever appears, to the best of our judg¬
ment, to be the truth.
To complain of this,—to reject or undervalue
the revelation God has bestowed, urging that it
is no revelation to us, or an insufficient one, be¬
cause unerring certainty is not bestowed also,—
because we are required to exercise patient dili¬
gence and watchfulness, and candour, and hum¬
ble self-distrust,—this would be as unreasonable
as to disparage and neglect the bountiful gift of
eyesight, because men’s eyes have sometimes de-
DISS. III.
ceived them ; because men have mistaken a pic¬
ture for the object imitated, or a mirage of the
desert for a lake; and have fancied they had the
evidence of sight for the sun’s motion; and to
infer from all this that we ought to blindfold our¬
selves, and be led henceforth by some guide who
pretends to be himself not liable to such decep¬
tions.
The two great volumes,—that of Nature, and
that of Revelation, which God has opened before
us for our benefit, are in this respect analogous.
Both are in themselves exempt from error ; but
they do not confer complete exemption from all
possibility of error on the student of them. As
the laws of nature are in themselves invariable,
but yet are sometimes imperfectly known, and
sometimes mistaken, by natural philosophers, so
the Scriptures are intrinsically infallible, but do
not impart infallibility to the student of them.
Even by the most learned, they are in many parts
imperfectly understood ; by the “ unlearned and
unstable” they are liable to be “wrested to their
own destruction.”
But still, if no errors or dissensions had arisen
in the Church during the days of the Apostles,
and then, when these inspired teachers were re¬
moved, heresies and schisms {eyfaiLara, divisions)
had arisen for the first time, we might have felt
as if God had forsaken us, and as if Christians
were exposed to such trials as had not been ori¬
ginally designed. Or we might have imagined
(as indeed some persons have imagined) that God
would still grant us inspiration, attested by mi¬
raculous signs, if we were not wanting in faith,
and in earnest supplication for such gifts.
And accordingly, in almost every Age of Chris¬
tianity, there have been persons who have per¬
suaded themselves that miraculous powers and in¬
spiration actually are bestowed on themselves or
on their Church; and these pretensions are be¬
lieved by such as decide according to their own
wishes and conjectures, without any rational
proofs.
But when we come to examine Scripture His-
3 s
506
PRELIMINARY DISSERTATIONS.
tory, we find that, even in the times of the Apos¬
tles, false teachers did “ arise, speaking perverse
things, to draw away disciples after them,”1 and
that Christians were thus divided into rival sects.
And this, the Apostles teach us, is a part of the
appointed trial to which we are to be subjected
here on earth. “ There must needs be heresies,
that they which are approved may be made mani¬
fest” (1 Cor. xi. 19), that is, that men may have
to exercise their care and candour in chusing
between truth and error.
And since God did think fit that Christians
should have to encounter such trials, He merci¬
fully provided that they should be forewarned
“ to take heed to themselves.” The errors and
corruptions introduced, even in the days of the
Apostles, are recorded in our Sacred Books, on
purpose, no doubt, to put us on our guard ; to pre¬
pare us to be watchful against corruptions of
Christianity in all other Ages of the Church; and
also to prevent our being disheartened at finding
ourselves exposed to such a trial.
It is not the design of this Dissertation, nor
indeed would its limits permit, to give an histori¬
cal account of each of the various corruptions of
Christianity which have taken place in different
Ages and Countries. It will be sufficient to give
a sketch of the principal sources from which
they arose, and of the means by which, in many
instances, they were encouraged and kept up.
These two general rules, then, are to be kept
in mind :—
1st, That whatever opposed Christianity at
the outset, afterwards tended to mix itself up with
the Religion, and corrupt it.
2dly, That as far as any corruptions depended
on local and temporary circumstances, so far,
they would be likely soon to die away, without
spreading widely; but so far as they were con¬
nected with Human Nature, we may expect to
find them appearing again and again, in various
Countries.
I. First, then, we have said that the causes
which, at the beginning, led to open hostility
against the Gospel, aftenvards operated to cor¬
rupt it. All those human faults and follies—all
those prejudices, and infirmities, and vices—
which originally disposed men to reject the Chris¬
tian religion, found their way into it, in propor¬
tion as it prevailed.
At first, almost all those whose notions
and whose dispositions were wholly adverse to
Christianity, rejected it altogether, and endea¬
voured to put it down: though even from the very
first there were exceptions to this rule; as we see
in the instances of Iscariot, and of Simon the Sor¬
cerer. But as the Religion spread, and became less
and less unpopular, and the number of disciples
multiplied more and more, there was a continually
increasing number of persons who, though mem¬
bers of Christian churches, had not fully under¬
stood the character of the Gospel, nor imbibed
the spirit of it. And these introduced into the
Religion the same kind of errors and wrong prin¬
ciples as had originally been openly arrayed
against it.
The chief opposition to the Gospel arose from
(1.) Judaism; (2.) Pagan Superstitions; (3.) Hea¬
then Philosophy; (4.) Immorality of Character;
and, (5.) Worldly Policy.
And the spirit of Judaism, of Paganism, &c.,
afterwards found their way into Christianity,
and tended to corrupt it.
(1.) It has been pointed out in an earlier part
of this Dissertation, how much opposed the pre¬
vailing Jewish notions and prejudices were to the
religion of Jesus Christ.
And accordingly, one of the very earliest at¬
tempts to corrupt Christianity was made by the
Judaizing teachers, who were continually endea¬
vouring to bring the Gentile believers under the
yoke of the Mosaic Law. (Acts xv., Gal. ii.,
Phil, iii.)
(2.) Then, again, of the opposition of the Pa¬
gan worshippers to the Gospel, we find many in¬
stances mentioned in the Book of the Acts of the
Apostles; especially in chap. xvi. 20, 21; and
xix. 27.
And we find, from time to time, attempts
made to incorporate into Christianity supersti¬
tions borrowed from Paganism, or of a similar
nature.
1 Acts xx. 28, perverted doctrines, ^sa-rja^ba.
DISSERTATION THIRD.
507
The earliest, perhaps, of these corruptions of
Christianity, was that introduced by those very
ancient heretics the Gnostics, whom the Apostle
John was particularly occupied in opposing,
both in his Epistles and in the opening of his
Gospel.
These men, it is well known, blended with
Christian doctrines many of the notions of the
Pagans, of the Persian, and some other Eastern
Nations. The religious system of these nations
consisted in acknowledging and reverencing two
Beings of equal power,—a good and an evil god,
—whom they called Ormuzd and Ahriman. And
some of their descendants, in the same regions,
at this day, are said to retain this faith, and to
be worshippers principally of the evil god.
The Gnostics accordingly taught, among other
things, that the world was not created by the Su¬
preme God, but by an Evil Being, or by a certain
inferior god.1
But, as has been above said, various other Pa¬
gan errors, or errors resembling those of Pagan¬
ism, have from time to time, crept into the Chris¬
tian Church.
(3.) The ancient heathen philosophers again,
who believed little or nothing of the popular su¬
perstitions, were no less opposed to the Gospel,
which they derided as “ foolishness.” And many
of them, when they afterwards embraced Chris¬
tianity, endeavoured to reconcile it with their
philosophical speculations, and thus to be wise
above that which is written.
It is evidently to this danger that Paul is allud¬
ing, in many passages ; especially when he warns
the Colossians, “Beware lest any man spoil you
through philosophy and vain deceit, after the
rudiments of the world, and not after Christ.”
(Col. ii. 8. See also 1 Cor. i. 20-28.)
It appears, therefore, that even in the Aposto¬
lic Age, men had begun to introduce into Chris¬
tianity presumptuous speculations on matters not
revealed in Scripture, and to make the Gospel a
field for the exercise of their philosophical inge¬
nuity. But in later ages this evil prevailed to a
far greater degree.
(4.) As for moral depravity, no one can doubt
how much this must have led many persons to
shut their ears against the evidences for a reli¬
gion which required them to reform their lives.
The description given of Felix, the Governor,
would no doubt have suited a great number of
others : “ When Paul reasoned of righteousness,
temperance, and the judgment to come, Felix
trembled, and said, Go thy way for this time;
when I have a convenient season I will call for
thee.”
But when persons of this character did become
members of the Church, as it appears many did,
even in the time of the Apostles, they naturally
sought to accommodate the religion to their own
corrupt characters. This seems to have been
more particularly the case with those Gnostics
above mentioned. For they taught that men are
to be saved by what they called “ knowledge 2
of the Gospel,” while living the most immoral
life, and yet having no sin (that is nothing im¬
puted to them as sin) but being accounted right¬
eous without “doing righteousness.” (1 Johniii.)
And this it was that made the Apostle John so
vehement in his censure of them.
But there are many allusions in the Apostolic
Epistles, to others besides these Gnostics, who
sought to “ hold the truth in unrighteousness.”
(Romans i. 18.)
(5.) Lastly, worldly policy was evidently one
of the chief causes which in the outset, acted as
a hindrance to the reception of Christianity. It
is plain, from the very nature of the case, that all
views of worldly ambition,—all desire of worldly
profit or advantage of any kind,—all considera¬
tions of supposed political expediency,—must
have been, at first, arrayed in opposition to the
Gospel. And every part of the sacred narrative
confirms this. We find the Jewish rulers influ¬
enced by the fear that “ the Romans would come
and take away their place and nation.” (John
x. 48.) We find them urging before Pilate, that
“whosoever maketh himself a king, speaketh
against Cassar.” And wefind the same sort of plea
repeatedly used to the Roman governors, and
often with effect. (See Acts xvii. 7, and xix. 23.)
And again, the poverty, hardships, and perse-
Thence denominated t>y them ^rifAiov^yos.
2 Hence their title of “Gnostics;” that is, persons knowing the Gospel.
508
PRELIMINARY DISSERTATIONS.
cutions, which the early Christians had been so
earnestly forewarned of by our Lord (John xvi.
1, 2), and to which they were actually exposed,
must have operated very strongly in prejudicing
all men of a worldly character against the religion.
Of course, in proportion as Christianity became
less unpopular, and more generally received, this
cause would less and less operate in making men
reject the religion, and would be more and more
likely to corrupt it. In proportion as worldly-
minded men became members of the Church, they
would naturally endeavour to wrest the Religion
to their own views of ambition or of profit.
This could not be expected to take place to the
same extent in the earliest Ages as afterwards.
Yet we find that even in the days of the Apostles,
men had crept into the church who were tainted
with avarice or worldly ambition, and who cor¬
rupted the Christian doctrines so as to favour their
own views. For we find Paul cautioning Timo¬
thy against “ perverse disputings of men of cor¬
rupt minds and destitute of the truth, who regard
religion as a source of profit.”1
All the principal causes, then, which occa¬
sioned opposition to Christianity, at the outset,
led afterwards to the corruption of the Religion;
and accordingly, some of the principal corruptions
which have, at various times, been introduced, will
be noticed under the same five heads under which
we have, just above, treated of the sources of the
original opposition to the Gospel. Those causes,
which had begun to operate even in the days of
the Apostles, had, of course, more of this corrupt¬
ing influence in later times. In proportion as
the dangers to the Church from without were
diminished, by the increasing prevalence of the
Religion, the dangers from within naturally in¬
creased. For, the number must of course have
become greater, of members of the Church who
were such merely because they had been brought
up as children of Christian parents, or because
Christianity was the prevailing religion; and
who would have rejected it when first preached,
from their having an unconverted heart, and
being strangers to the true spirit of the Gospel.
And such persons will always be likely to aim at
bringing their religion into a conformity with
their own characters, instead of conforming their
own characters to the Religion.
II. The second general rule we laid down was,
that so far as any human fault or folly was pecu¬
liar to some particular time or Country, its ef¬
fects may be expected soon to have passed away
without spreading very far; but so far as it be¬
longed to human nature in general, we must ex¬
pect to find the evil effects of its reappearing
again and again, in various forms, in all Ages, and
in various regions.
And for the most part it will be found that the
prejudices and evil dispositions of men which
have introduced religious error, and accordingly
the religious errors themselves thence arising,
are different in their outward form according to
the peculiar circumstances of each time and
place ; but that in substance and at bottom, they
are nearly alike, always and everywhere.
For example, the prejudice of the Jews in
favour of their own nation and institutions, gave
rise to that very early heresy above noticed (see
Acts xv., and Gal. ii.), of those who taught that
all Christians were bound to keep the Mosaic
Law ; or at least, that such as did so had attained
a superior degree of sanctity. The violation of
the UNITY [Oneness] of Christ’s religion, by
thus dividing Christians into two classes, ad¬
mitted to different degrees of religious privilege,
has been already noticed. The sect of Judaizing
Christians, however, thus founded, seems not to
have lasted long. The destruction of Jerusalem
and its Temple appears to have soon put an end
to it. But the general tendency towards this
violation of Christian Unity, being not peculiar
to the Jews, but a part of human nature, has
shewn itself again and again, under various forms,
in various portions of the Church.
What are called the “ Monastic Orders,”
which have long existed in many Churches, are a
striking instance of this. Though the great
mass of Christians have been solemnly dedicated
to Christ at baptism, wherein they engage to be
his “ faithful soldiers and servants yet many
have thought fit to take on themselves a new and
1 1 Tim. vi. 5. ara^a-^av tivtu raja iutrijZiiw
DISSERTATION THIRD.
509
distinct engagement, not binding on Christians
generally, but only on such as have professed this
new and superior kind of Christianity. The
members of such Orders are often called the
“ religious and there is one well-known order
called the “ Society of Jesus as if the Church
itself were not the Society of Jesus, and all its
members bound to be religious. And the mem¬
bers of these Orders are supposed to possess a
certain extraordinary kind of holiness, from their
imposing on themselves certain restrictions, and
privations, and other sufferings, according to
rules laid down, not by Scripture for all men,
but by particular founders for their own Order.
Now this is clearly in violation of the ONENESS
of Christ’s religion.
Again, one may find persons dividing Chris¬
tians into “ Elect,” and not Elect—those who
are, and those who are not “ God’s peopleac¬
counting some Christians “ Saints,” and others
not; some “Evangelical” and others not. Though
“ Saints ” was the very term used by the apostles
to denote what we call “ Christians;” and though
it is plain that since Christianity is the religion
of the “ Gospel” [Evangelium], all doctrines and
all persons must be Evangelical or not, exactly
in the same sense, and in the same degree, that
they are, or are not Christian.1
Those, also, who regard Christian Ministers as
sacerdotal Priests, acting as a kind of mediators
between God and the People, are evidently going
very far towards such a distinction between
Clergy and Laity as is at variance with the Apos¬
tolical view of Christian-Unity.
And, it may be added, that there is a consider¬
able number of persons who make a division of
Christians into the two classes, of Communicants
and non-Communicants. For there are very
many of these latter, who, though far from dis¬
regarding Christian duty altogether, or absenting
themselves from public worship, yet consider
that, so far from being a duty, it would be a
wrong thing for them to attend the Lord’s Table,
unless they were determined to become Saints in
some peculiar manner, different from what is ex¬
pected of Christians generally. And this they
think it would be presumptuous for them to pre¬
tend to. They regard themselves, in short, as
an inferior class of Christians.
And, it is to be observed, that the division of
worshippers into different classes in respect of
religious privileges, belonged, even much more,
to the Pagan religions, than to the Jewish. For
among the Pagans, certain persons were “ ini¬
tiated ” into such “ Mysteries ” of their religion
as were carefully kept secret from the vulgar.
And this was not the case with the Mosaic re¬
ligion.2 The division, therefore, of Christians
into such classes, is what the heathen con¬
verts, no less than the Jewish, would be in¬
clined to. And it is, moreover, something so
natural to man, that, in one shape or another, it
has appeared in almost all parts and Ages of the
Church.
And so it is with most of the other corrup¬
tions of Christianity. The particular form in
which each has appeared, will have generally
been determined by local and temporary cir¬
cumstances; and, when these circumstances are
changed, that particular corruption will die away,
to reappear (so far as it pertains to the character
of the “ natural man,”) under some new shapes,
in various Countries.
It is to be observed, however, that those cor¬
ruptions of Christianity which arise from the
mixing up of Judaism with it, are, for one rea¬
son, likely to be more lasting than most others,
and to be oftener revived. Christians acknow¬
ledge that the Mosaic Dispensation came from
God. And that, and also the Christian Dispen¬
sation, are contained in the volume which we call
the Bible. Now, any one who regards the Bible
(which many Christians do) as one book, contain¬
ing divine instructions, without having formed
any clear notions of what does and does not be¬
long to each Dispensation, will, of course, fall into
1 There are, indeed, some persons who confine both the terms “ Christian” and “ Evangelical” to those who exactly agree
with them in all points, and belong to their Party ; regarding all others as excluded from the Gospel covenant. But there
are, again, some who make the distinction above alluded to.
2 Josephus remarks, as a distinction between the Pagan and the Jewish religions, that this latter made known to all the
People the mysteries of their religion, while the Pagans concealed from all but those specially “initiated” the mysteries of
theirs.
510
PRELIMINARY DISSERTATIONS.
the greatest confusion of thought. He will be
like a man who should have received from his
father, at various times, a great number of letters
containing directions as to his conduct, from the
time when he was a little child just able to read,
till he was a grown man ; and who should lay
by these letters with care and reverence, but in
a confused heap, and should take up any one of
them at random, and read it without any refer¬
ence to its date, whenever he needed his father’s
instructions how to act.
Accordingly, many erroneous notions, wholly
or partly drawn from Judaism, have again and
again found their way into the Christian Church.
For example, there have been in almost all
Ages of the Church, persons who have taught that
Jesus Christ is to come upon earth and reign in
great worldly splendour at Jerusalem for a thou¬
sand years; which period is thence called Mil¬
lenium. And superior privileges, as God’s pecu¬
liar People, are then to be restored (according to
this doctrine) to the Jews ; that is, to such Jews
as shall have continued unbelievers ; not, to the
descendants of those great multitudes of them
who embraced Christianity in the days of the
Apostles, and since, and who thereupon soon be¬
came blended with the Gentile Christians. But
the remnant of the Jews who shall have obsti¬
nately rejected the Gospel up to that time, are
then to be restored to their own land, and to have
a superiority in God’s sight over men of Gentile
race. And the Temple at Jerusalem is to be
restored, and to be again the place of peculiar
holiness, whither all men are to resort to wor¬
ship.
Now these expectations of a Christ, who is to
be a great and victorious temporal king, and of a
kingdom of earthly glory, and of the restoration
of the Temple, and of the exaltation of the Jews
above all other people, are precisely those which
the Jewish nation were so wedded to when our
Lord came, and which led most of them to reject
Him.
There are several other religious errors which
have arisen from the same cause,—the practice
of confusedly blending together the Law and the
Gospel. Thus, some persons, as we had before
occasion to remark, represent temporal rewards
and punishments as a part of the sanction of the
Christian Dispensation ; and again, future re¬
wards and punishments as a part of the sanction
of the Mosaic. And this, as we have already
said, destroys all clear notions of either system,
and leads to great and dangerous practical errors,
besides exposing our Scriptures to unanswer¬
able objections from infidels.
And again, the introduction into Christianity of
sacerdotal Priests,1 Altars, Sacrifices, and Temples,
which is so utterly repugnant to the whole cha¬
racter of the Gospel, may be traced both to Juda¬
ism and to Paganism. For all these things were
common to them both; though the J ewish Priests
offered sacrifices to the true God, and the Pagan
Priests to idols.
The Priests of the Israelites were appointed by
the Almighty Himself, for the express purpose
of offering sacrifices, in the name and on the be¬
half of the people ; they alone were allowed to
make oblations and burn incense before the Lord;
it was through them that the People were to ap¬
proach Him, that their service might be accept¬
able. A very great portion of the Jewish reli¬
gion consisted in the performance of certain cere¬
monial rites, most of which could only be duly
performed by the Priests, or through their me¬
diation and assistance; they were to make in¬
tercession and atonement for offenders ; they,
in short, were the mediators between God and
Man.
And among the Pagans, whose institutions ap¬
pear to have been, in great measure, corrupt imi¬
tations of those of the Patriarchal religion, we find,
1 Our word “ Priest” is formed from n^ar^ursons; which is, translated, an “ Elder,” in our version of the Bible. But the
word which our translators have rendered “ Priest” is, in the original Greek, 'Ugibs, in Latin, Sacerdos, and is always ap¬
plied to a sacrificing minister. And the word is never applied to any one under the Christian dispensation, except Jesus
Christ alone, our great and only High Priest, who offered up Himself a sacrifice for man’s redemption.
Now we may be sure that, if the Apostles had ordained any one to the office of a sacerdotal priest, or had designed that
there should be any such in the Christian Church, there would have been mention made of it in the Book of Acts, and in the
Apostolic Epistles.
Whenever the title of priest ['Is^sliy] is applied to any Christians, it is applied to all Christians (Rev. v. 10, and 1 Pet. ii. 9)
as offering up themselves to God.
DISSERTATION THIRD.
511
in like manner, Priests, who were principally,
if not exclusively, the offerers of sacrifices, in be¬
half of the State and of individuals,—intercessors,
supplicating and making atonement for others,—
mediators, as before, between Man and the object
of his worship.
The office of priest, then, in that sense of the
word which we are now considering, viz., as equi¬
valent to 'legsug, being such as has been described,
it follows that in our religion, the only Priest,
in that sense, is J esus Christ Himself; to whom
consequently, and to whom alone, under the Gos¬
pel, the title is applied by the inspired Writers.
He alone has offered up an atoning sacrifice for
us, even the sacrifice of his own blood ; He “ever
liveth to make intercession for usHe is the
“one Mediator between God and man“through
Him we have access to the Father; and no man
cometh unto the Father, but by Him.”
As for the Ministers whom He, and his Apostles,
and their successors, appointed, they are com¬
pletely distinct from Priests in the former sense,
in office, as well as in name. Of this office one
principal part is, that it belongs to them (not ex¬
clusively indeed, but principally and especially)
to preach the Gospel,—to instruct, exhort, ad¬
monish, and spiritually govern, Christ’s flock.
His command was to “ go and teach all nations
—to “ preach the Gospel to every creature and
these Christian Ministers are called in the Epistle
to the Hebrews, “ those that bear rule over them,
and watch for their souls, as they that must give
an account.” Now it is worthy of remark, that
the office we are at present speaking of made no
part of the especial duties of a Priest, in the other
sense, such as those of the Jews, and of the Pa¬
gans. Among the former, it was not so much
the family of Aaron, as the whole tribe of Levi,
that seem to have been set aside for the purpose
of teaching the Law; and even to these it was
so far from being in any degree confined, that
persons of any tribe might teach publicly in the
synagogues on the Sabbath-day ; as was done by
our Lord Himself, who was of the tribe of Judah,
and Paul, of the tribe of Benjamin, without any
objection being raised; whereas an intrusion into
the Priest’s office would have been vehemently
resented.
And as for the Pagan Priests, their business
was rather to conceal, than to explain, the mys¬
teries of their religion;—to keep the people in
darkness, than to enlighten them. Accordingly
the moral improvement of the people, among the
ancients seems to have been considered as the
proper care of the legislator; whose laws and
system of public education generally had this ob¬
ject in view. To these and to the public disputa¬
tions of philosophers, but not at all to the Priests
of their religion, they appear to have looked for
instruction in their duty.
That the Christian Ministry, on the contrary,
was appointed in great measure, if not principally,
for the purpose of giving religious instruction
and admonition, is clearly proved both by the
practice of the Apostles themselves, and by Paul’s
directions to Timothy and to Titus.
Another, and that a peculiar and exclusive
office of the Christian Ministers, is, the adminis¬
tration of the Sacraments of Baptism and of the
Lord’s Supper. But this administration does
not at all assimilate the Christian Priesthood to
the Pagan, or the Jewish. The former of these
rites is, in the first place, an admission into the
visible Church ; and therefore very suitably re¬
ceived at the hands of those whose especial busi¬
ness is to instruct and examine those who are
candidates for baptism, as adults, or who have
been baptised in their infancy ; and in the se¬
cond place, it is an admission to a participation
in the gifts of the Spirit, which constitute the
Church “the temple of the Holy Ghost.” The
treasury, as it were, of divine grace is then thrown
open, to which we may resort when a sufficient
maturity of years enables us to understand our
wants, and we are inclined to apply for their re¬
lief. It is not, let it be observed, through the
mediation of an earthly Priest that we are ad¬
mitted to offer our supplications before God’s
mercy-seat; we are authorised, by virtue of this
sacred rite, to appear as it were in his presence
ourselves ; needing no intercessor with the Fa¬
ther, but his Son Jesus Christ, both God and
man. “ Having therefore,” says Paul, “ boldness
to enter into the holiest by the blood of Jesus,
by a new and living way, which he hath con¬
secrated for us, and having an High Priest over
the house of God, let us draw near with a true
heart, in full assurance of faith, having our hearts
512
PRELIMINARY DISSERTATIONS.
sprinkled from an evil conscience, and our bodies
washed with pure water.”
The Sacrament of the Lord’s Supper, again, is
not, as the Romanists unwarrantably pretend, a
fresh sacrifice, but manifestly a celebration of
the one already made. And the rite seems
plainly to have been ordained for the express
purpose (among others) of fixing our minds on
the great and single oblation of Himself, made by
the only High Priest “ once for allthat great
High Priest who has no earthly successor. And
all the communicants are alike partakers, spirit¬
ually, of the Body and Blood of Christ (i. e. of
His Spirit), of which these are the emblems),
provided they themselves are in a sanctified and
right frame of mind. It is on the personal holi¬
ness of the Communicant, not of the Minister,
that the efficacy of the sacrament depends ; he,
so far from offering any sacrifice himself, .refers
them to the sacrifice already made by another.
Such being, then, the respective offices of these
two Orders of men (both now commonly called
in English, “ Priests,” but originally distinguish¬
ed by the names of Hiereus and Presbyteros), we
may assert that the word in question is ambi¬
guous ; denoting, when thus applied to both, two
things essentially distinct. It is not merely a
comprehensive term, embracing two species
under one class, but rather an equivocal term,
applied, in different senses, to two things of dif¬
ferent classes. At least, it must be admitted,
that what is most essential to each respectively,
is wanting in the other. The essential charac¬
teristic of the Jewish Priests, was (not their be¬
ing ministers of religion; for that, in a certain
sense, all the Levites were, but) their offering
sacrifices, and making atonement and interces¬
sion for the. people ; whereas, of the Christian
Minister, the especial office is religious instruc¬
tion, and the administration of rites altogether
different in their nature from the offering of
sacrifices ; totally precluding the idea of his
being himself the mediator between God and
Man.
And the contrast in this point, between the
Christian religion on the one hand, and all that
exist, or ever existed, besides it (including the
Jewish), on the other, will afford, if we rightly
consider when, and by whom, our faith was in¬
troduced, one of the most powerful evidences of
its truth.
The Apostles, though attentive to the regular
government of the churches they founded, or¬
daining, for various services, Elders, and other
Ministers, male and female, (the latter being
known by the title of “ Widows,”) yet appointed
no order of Priests in the sense of Hierews (familiar
as they must have been with the name), answer¬
ing to the sacrificing Priests of the Jewish and
of the Pagan religions. The same observation
will apply to the Temple. The term was fami¬
liar to the New Testament writers; but it is never
once applied by them to a Christian place of wor¬
ship ; always to the worshippers themselves col¬
lectively;—to the Christian congregation; as e.g.
“ Know ye not that ye are the temple of the Holy
Ghost, which dwelleth in you V' “ Your body is
the temple of the Holy Ghost.” “ Ye, as lively
stones, are budded together into an holy tem¬
ple,” &c.
All this is indeed perfectly intelligible to any
one who understands the character of our reli¬
gion. It is perfectly consistent with the Gospel
scheme; but it is utterly at variance wdth the
notions which would naturally have occurred to
the unassisted mind of Man.
A further proof of this, if further could be
needed, is furnished by the changes which were
introduced in after ages. The very institution
which Christianity in its pure state had abro¬
gated, was grafted into it, as it became corrupted
with human devices. An order of Priests in the
ancient sense, offering pretended sacrifices, on a
pretended altar, in behalf of the People, was in¬
troduced into the Christian scheme, in such utter
contradiction both to the spirit, and the very let¬
ter of it, that they were driven to declare the bread
and wine of the Eucharist miraculously changed
into literal flesh and blood offered up day by day
repeatedly: although the founders of our reli¬
gion had not only proclaimed the perfection of
the one oblation of our Lord by Himself, but
had even proved the imperfection of the Leviti-
cal sacrifices, from the very circumstance of their
being repeated “year by year continually;” in¬
asmuch as they would have ceased ” (says the
Apostle) “ to be offered,” if, like the sacrifice of
Christ, “ once for all,” they could “ have made
DISSERTATION THIRD.
513
the comers thereunto perfect.” Now, if when
the religion had actually been established ^u^th-
out Altar, without Sacrifice, without Priest on
earth, all these were introduced into it, in opposi¬
tion to its manifest character, through the strong
craving (if we may so speak) of “ the natural
man ” after them; how much more might we
expect—with what complete certainty—that men
brought up Jews, and having never seen or
heard of any religion, true or false, without
Priests, would have instituted, had they been left
to themselves, an order of sacrificing Priests in
their new religion? And how certain, that,
since they carefully abstained from this and pro¬
vided against it in the terms they employed ;—■
how certain—that they were not left to them¬
selves, but proceeded under the guidance of a
divine director ?
The corruptions then subsequently introduced
into Christian churches, in respect of the Priest¬
hood, do in reality, by shewing what the ten¬
dency of human nature is, go to prove the super¬
human origin of the original institution. These
have, however, afforded ground for cavil against
Christianity itself, to those who, ignorantly or
designedly, confound the religion itself with this
perversion of it.
The Greek and Romish, and some other
Churches have, in fact, in some great degree,
transformed the Preshyteros, the Priest of the
Gospel Dispensation, into the Afierews, or Levi-
tical Priest: thus derogating from the honour of
the ONE great High Priest, and altering some of
the most characteristic features of his religion,
into something more like Judaism or Paganism
than Christianity.
To enter into the detail of this perversion,
would lead to a discussion not only too long for
our present purpose, but which in fact must have
been forestalled by any one who is at all ac¬
quainted with the abuses formerly prevailing
among us.
Before the Reformation of our Church, the
Priest professed, like the Jewish, to offer sacrifice
(the sacrifice of the Mass) to propitiate God to¬
wards himself and his congregation : the efficacy
of that sacrifice was made to depend on sincerity
and rectitude of intention, not in the Communi¬
cants themselves, but in the Priest; he assuming
Diss. III.
the character of a mediator and intercessor, prayed
not with but for the people, in a tongue unknown
to them, and in an inaudible voice; the whole
style and character of the Service being evidently
far different from what the Apostle must have
intended, in commanding us to “ pray for one
another.” The Priest undertook to reconcile
transgressors with the Almighty, by prescribing
penances, to be performed by them, in order to
obtain his absolution; and, profanely copying our
only High Priest, pretended to transfer to them
his own merits, or those of the Saints. He,
like a Pagan, rather than a Jewish, Priest, kept
hidden from the people the volume of their faith,
that they might, with ignorant reverence, submit
to the dominion of error, instead of being “ made
free by the truth,” which he -was expressly com¬
missioned to make known; thus hiding the
“ candle under a bushel,” which was designed to
“ be a light to lighten the nations.”
In short, whoever will minutely examine, with
this view, the errors of our unreformed Church,
will find that a very large and important portion
of them may be comprehended under this one
general censure, that they destroyed the true cha¬
racter of the Christian Priesthood, substituting
for it, in great measure, what cannot be called a
Priesthood, except in a different sense of the word.
These errors, in short, go far towards changing
the office of Preshyteros into that of Hiereus.
There is another point in which superstitions,
very much like those of the Pagans, have cor¬
rupted the worship of many Christians. We had
occasion to remark, in an earlier part of this Dis¬
sertation, that many of the Pagan gods were de¬
ceased Men, whom they had deified on account
of some supposed extraordinary excellence of cha¬
racter, and eminent services to mankind, or to
their countrymen.
Some of these they worshipped as gods ; others
under the title of demi-gods, or heroes. Any man
whom his countrymen had been accustomed to
venerate very highly in his lifetime, they natu¬
rally first wished, and then hoped, and lastly be¬
lieved, might be elevated after death to such an
exalted state as to enable him to hear them, and
to do them services, either by himself, or by mak¬
ing applications on their behalf to some superior
god. And just as persons in humble life generally
3 T
514
PRELIMINARY DISSERTATIONS.
apply to a king or other great man, not directly,
but through his ministers and other attendants,
so, a large portion of the Pagan worship was ad¬
dressed to some whom they accounted inferior
gods.
But, moreover, they supposed each of these in¬
ferior deities to have a special regard for his own
country. Thus Romulus (Quirinus) was the tute¬
lar god of Rome, and Theseus of Athens, &c.
And even private families had gods of their own,
who among the Romans were called “ Lares,” and
“ Penates.” And the superior gods also were sup¬
posed to have partialities for particular regions or
races. Thus Minerva [Pallas] was tutelar goddess
of Athens ; and Diana [Artemis] of Ephesus ; and
Juno, of Argos and Samos, &c. The power also
of many of their gods was supposed to be limited
to particular places, or to particular offices. Thus,
we find the Syrians fancying that the God of Is¬
rael was the God of the hills (1 Kings xx. 23),
and would not be able to succour his People on
the plains. And Castor and Pollux were supposed
to protect sailors, &c.
And moreover, there were certain images and
temples, which were supposed to have a superior
sanctity above other images and temples of the
same god. And again, some particular temples
were resorted to by those who had need of some
particular kind of service. Thus, oracles were
supposed to be given by Apollo, not in every one
of his temples, but only in those at Delos, and
Delphi, and some others. And it was the like
with respect to various other benefits sought for
from several of the gods.
Such, then, being the natural tendency of man¬
kind, the consequence was that many Christians,
though they did not introduce into the Christian
Religion the worship of the very same gods which
were worshipped by their pagan forefathers, yet
fell into the same kind of superstitions.
Their deep reverence for the Blessed Virgin,
and for the Apostles and other eminent Chris¬
tians, led them to hope, and then to believe, that
these persons were able after their departure from
Earth, to hear any one who called on them, and
to make prayers of intercession for them. And
the evil of this practice of invoking departed
Saints, was,—and still is, to many Christians—
disguised by their overlooking the difference be¬
tween asking the prayers of the living and of the
departed. No doubt many persons entreated (as
Simon the Sorcerer did, Acts viii.) Peter or other
Apostles to pray for them. And James expressly
exhorts Christians to pray for one another (Jas.
i. 16). No Christian need scruple to ask any one
whom he considers to be a pious and worthy man
to pray for him. But when it came to be believed
that a holy person, when removed from the Earth,
can hear the addresses of thousands and millions
of his votaries calling on him in all parts of the
world, and know the secret dispositions of mind
in each several person that invokes him, this be¬
lief did in fact deify him.
Whatever subtle explanations may be attempted
of the way in which glorified “ saints ” are able
to hear, from various regions, and to repeat, more
prayers in the day than there are minutes in the
twenty-four hours, it is plain that at least the
great mass of their worshippers must regard them
no less as gods than the ancient pagans did the
Beings they worshipped.
The consequence was, that the chief part of the
worship which is due to the “ JEALOUS God”
came to be paid to the Virgin Mary, and those
other “ Saints” (amounting to several hundreds),
who were, from time to time, enrolled on the list.
And thus did Christians introduce into their
Religion, under new names, almost every one of
the ancient pagan superstitions just above no¬
ticed. They knelt before images and pictures of
the saint they invoked. They attributed peculiar
holiness to some particular image, or chapel, above
others dedicated to the same saint. They had
patron saints (answering to the tutelar gods of
the Pagans) presiding over particular nations,
or classes, or persons. One saint, again, was sup¬
posed to be peculiarly powerful in procuring some
particular kind of relief or benefit; and another,
in another kind. In short, we have only to look
back to what has been just said of the Pagan wor¬
ship, and we shall see how closely it corresponds
in every point (besides many more which might
have been added) with the worship which has
been, in some Churches, introduced into Chris¬
tianity.
And, on the other hand, if we look to the Scrip¬
tures, we shall plainly see that it is not thence
that the invocation of Saints could have been de-
DISSERTATION THIRD.
515
rived. They not only contain nothing to warrant
it, but they seem framed purposely to guard all
who are sincerely desirous of following Scripture,
against this very corruption. Though we find in
the Book of Acts narratives of the death (Acts
vii., xii.) of the two martyrs, Stephen, and James
the Apostle, the brother of John, there is no
mention of their being invoked after death. And
when God saw fit to convey his commands to Cor¬
nelius, and again to Paul (Acts x., xxvii.) by a
created Being, it is not either of these blessed
martyrs, but an Angel, that is sent.
The Virgin Mary, again, is hardly so much as
named throughout the Acts1 and Apostolic Epis¬
tles. Now this silence respecting her is utterly
inconceivable, supposing it had been the practice
of the early Christians to pray to her. In the
Gospels, again, she is but rarely mentioned.
Even John, her adopted son, though in all
likelihood he must have long outlived her, does
not record her death, nor give any particulars of
her life ; and yet he wrote, as is universally be¬
lieved, purposely to supply the omissions of the
other Evangelists. And it is remarkable that we
gather from him incidentally, and only inciden¬
tally, that Mary had usually resided with Jesus,
who, at his death, committed her to the care of the
beloved Disciple ; and “ from that time he took
her to his home.” Why this sparing and un¬
frequent mention of her whom “ all generations
should call blessed,” and who must have been
personally so well known to many of the most
eminent disciples 1
Humanly speaking, this seems to us impossible.
We are left,—we are driven, to suppose that the
divine Spirit which guided the sacred Writers,
led them, whether consciously or unconsciously,
to suppress what they would naturally have re¬
corded, in order to guard against that supersti¬
tious veneration for the Virgin Mary, to which,
as experience shews, there is naturally so strong
a tendency in the minds of Christians. And the
few passages which do allude to her, furnish a
strong confirmation of the soundness of this con¬
clusion. They are chiefly such as are calculated,
and apparently designed, to repress superstitious
veneration. One of them records that, when the
mother and other kindred of our Lord were an¬
nounced as desiring to speak with Him, He took
occasion to point out that these had no claim, on
that ground, to especial reverence ; He turned to
his disciples, and said, “ Behold my mother and
my brethren!” Upon another occasion, when a
woman exclaimed—“ Blessed is the womb that
bare Thee, and the paps that Thou has sucked”
—He replied, “ Yea, rather blessed are they that
hear the word of God and keep it.” One of
those who did so, was, we may be sure, his mo¬
ther herself; but the mere circumstance of her
being his mother, did not, as He declares, imply
a blessedness equal to that of the humblest of his
faithful hearers. Does not the record of these
allusions to one of whom so little is recorded,
seem expressly designed to guard against that
superstitious error to which the tendency is so
natural, and, as experience has shewn, so strong?
Once more, it is mentioned in the narrative
contained in the second chapter of St John’s
Gospel, that the mother of Jesus was invited, as
well as himself, and his disciples, to the marriage-
feast at Cana. She seems to have been apprised
of his design to perform the miracle ; for she ap¬
plied to him when the wine was deficient. His
answer has not that roughness, indeed, which
our English translation gives it, from the use of
the term “ woman.” The word in the original
is one which denotes no disrespect; being found
in the classical Greek writers applied even to a
queen. But He plainly forbids her interference,
telling her that the time is not yet come for the
display of his miraculous power. Now, why is
her application to him, and his reply,—why is
even her presence on this occasion at all,—men¬
tioned in this place ? Evidently, for the purpose
of shewing that he would do no miracle at her
bidding ; that his filial reverence did not extend
to his admitting her interference in anything
connected with his ministry. It is a warning to
all who will be warned by Scripture, that they
must not be led by their veneration for the
mother of Jesus, to look for her intercession for
them with her Son. “ There is one mediator
1 Once very slightly, in Acts i.
516
PRELIMINARY DISSERTATIONS.
between God and Man,” Jesus Christ—between
Him and Man—none. He is himself ever at
hand; and if any man will seek to do his will,
“ He will come unto him, and make his abode
in him by his Spirit.”
Any one, therefore, who carefully follows the
teaching of the Evangelists and Apostles, will be
preserved from such errors as we have been
speaking of. But it was the disposition of “ the
Natural Man ” that originally led the Pagans to
corrupt the Religion revealed to the earliest gene¬
rations, and to “ worship the creature more than
the Creator.” And that very same disposition
has led many of those Christians who neglect
the guidance of Scripture, to introduce like cor¬
ruptions into Christianity.
III. In addition to these sources of corrup¬
tion, the tendency already mentioned to intro¬
duce philosophical speculations into Christianity
has shewn itself again and again under various
forms, in all ages of the Church, and has given
rise to a multitude of heresies.
Philosophy is not at all opposed to true Reli¬
gion, as long as men confine their speculations
to matters which properly come within the pro¬
vince of Reason.1
But in what relates to Divine Revelations, Rea¬
son should be confined to these two points :—
1st, To judge of the grounds on which any pro¬
fessed revelation should be received or rejected,
as being “ from Heaven, or of menand, Sdly,
To determine what it is that we are enabled and
required to learn from the Revelation which God
has actually given.
The restless spirit of philosophising, however,
was not easy to be subdued, or to be confined
within these limits. Even during the times of
the Apostles, and still more, after their depar¬
ture, many philosophers, on embracing Chris¬
tianity, transgressed their proper limits, and
sought to exercise their ingenuity on that sub¬
ject—one of so much interest and importance—
in order to maintain their superiority over the
vulgar, even in the knowledge of divine mys¬
teries. They acknowledged, for the most part,
that the Christian revelation had made known
things pertaining to God, which could not other¬
wise have been known: but these things they
seem to have regarded as fresh materials for hu¬
man reason to work upon ; and when the illu¬
mination from heaven—the rays of revelation—
failed to shed full light on the Gospel dispensa¬
tion, they brought to the dial-plate the lamp of
human philosophy.2
Accordingly, we find in very early times, cu¬
rious questions raised concerning the incarnation,
and the nature and person of the Lord Jesus.
One system so ancient as to be alluded to by John
in his Epistle, represented Jesus Christ as not
really “ come in the flesh,” but as a man in ap¬
pearance only. Other systems made Jesus to have
been born a mere human being, on whom, at his
baptism, a certain emanation (which they called
Christ) from the divine fulness, descended and
dwelt in Him. And endless were the questions
raised, and the different hypotheses set up, as
to the manner in which the divine nature was
united with the human in Jesus Christ ; whether
He was properly to be called one person, or two;
whether the Virgin Mary were properly to be
styled the Mother of God; whether Christ should
be regarded as of one substance, or of like sub¬
stance with the Father; whether the Deity suf¬
fered at the crucifixion ; in what way the sacri¬
fice of Christ was accepted as a satisfaction for
sin; why this sacrifice was necessary; besides
(in later times) an infinite number of equally
subtle speculations as to the nature of the Trinity,
—the divine decrees,—and, in short, everything
pertaining to the intrinsic nature of the Supreme
Being, and the explanation of all his designs and
proceedings. And yet the motions of the earth,
and the circulation of the blood, were not dis¬
covered till many ages after. The cause of the
vital warmth in animals, philosophers are not
1 It is remarked by Locke, that those who are for laying aside the use of Reason in matters pertaining to Revelation, re¬
semble one who should put out his eyes in order to make use of a telescope.
2 Some persons have been so much struck with the resemblance between some of Plato’s speculations, and those of certain
ancient Theologians, respecting the Trinity, as even to imagine that he must have received some revelation from Heaven!
But instead of concluding that Plato had imparted to him by inspiration knowledge beyond what was communicated to
the Apostles—or at least beyond what they were commissioned to teach—we ought rather to infer that those Theologians
had corrupted the simnlicitv of the Gospel by mixing up with it Plato’s philosophy.
DISSERTATION THIRD.
517
even yet agreed on; nor is it decided whether
light, heat, and electricity, are substances, or qua¬
lities of bodies. But as to the substance of the
Supreme Being, and of the human soul, many men
were (and are still) confident in their opinions,
and dogmatical in maintaining them; the more,
inasmuch as in these subjects they could not be
refuted by an appeal to experiment.
All these various systems of philosophical theo¬
logy were discussed in language containing tech¬
nical terms more numerous than those of almost
any science ; some of them taken from the sacred
Writers (we may say, in every sense of the phrase,
“ taken from them,” since hardly any theologian
confined himself to their use of the terms), and
others not found in Scripture, but framed for each
occasion. These were introduced professedly for
the purpose of puttingdown heresiesastheyarose.
That they did not effect this object, we know by
experience; which, indeed, would lead us to con¬
clude, that heresies were by this means rather
multiplied. We are inclined to think, that if all
Christians had always studied the Scriptures
carefully and honestly, and relied on these more
than on their own philosophical systems of divi¬
nity, the Incarnation, for instance, and the Trinity,
would never have been doubted, nor ever named.
And this at least is certain, that as scientific theo¬
ries and technical phraseology gained ground,
party animosity raged the more violently. The
advocates of the several systems did not, like the
ancient heathen philosophers, carry on a calm and
friendly dispute, but (to the disgrace of the Chris¬
tian name) reviled, and (when opportunity offered)
persecuted each other, with the utmost bitterness.
For each of them having not only placed the es¬
sence of Christianity in faith, but the essence of
faith in the adoption of his own hypothesis, and
strict adherence to his own use of the technical
terms of his theology, was led hence to condemn
all departures from his system, as involving both
blasphemy against God, and danger to the souls
of men. And they employed, accordingly, that
violence in the cause of what they believed to be
divine truth, which Jesus Himself and his Apos¬
tles expressly forbade in the cause of what they
knew to be divine truth. “ The servant of the
Lord,” says Paul, “ must not strive, but be gentle
unto all men, in meekness instructing them that
oppose themselves, if God, peradventure, will
give them repentance, to the acknowledging of
the truth.” (2 Tim. ii. 24, 25.) But those
who lose sight of the real character and design
of the Christian revelation, generally lose also
the mild, patient, and forbearing spirit of the
Gospel.
There is no one of the numberless systems we
have alluded to that has not been opposed, and
strongly condemned, by the advocates of some
different one; but they have not usually been con¬
demned on what appears to us to be the right
ground.
The proper objection to the various philoso¬
phical systems of religion,—the different hypo¬
theses or theories that have been introduced to
explain the Christian Dispensation,—is, not the
difficulties that have been urged (often with good
reason) against each separately; but the fault that
belongs to all oi them equally. It is not that
the Arian theory of the incarnation, for instance,
is wrong for this reason, and the Nestorian for
that, and the Eutychian for another, and so on ;
but they are all wrong alike, because they are
theories, relative to matters on which it is vain,
and absurd, and irreverent, to attempt forming
any philosophical theories whatever.
And the same, we think, may be said of the
various schemes (devised either by those Divines
called the Schoolmen, or by others) on which it
has been attempted, from time to time, to explain
other religious mysteries also in the divine na¬
ture and dispensations. We would object, for
instance, to the Pelagian theory, and to the Cal-
vinistic theory, and the Arminian theory, and
others, not for reasons peculiar to each one, but
for such as apply in common to all.
Philosophical divines are continually prone to
forget that the subjects on which they speculate,
are, confessedly, and by their own account, be¬
yond the reach of the human faculties. This is
no reason, indeed, against our believing any thing
clearly revealed in Scripture ; but it is a reason
against going beyond Scripture with metaphysi¬
cal speculations of our own. One out of the many
evils resulting from this, is, that they thus lay
open Christianity to infidel objections, such as it
would otherwise have been safe from. It is too
late, when objections are alleged from the diffi-
518
PRELIMINARY DISSERTATIONS.
culties involved in some theory, to reply, that the
whole subject is mysterious and above reason, and
cannot be satisfactorily explained to our imperfect
faculties. The objector may answer, “ Then you
should have left it in the original mysterious in¬
distinctness of the Scriptures. Your own expla¬
nations of the doctrines of your Scriptures you
must not be suffered to make use of as far as they
are admitted, and then, when they are opposed,
to shelter them from attack, as sacred mysteries.
If we enter on the field of philosophical argu¬
ment, we cannot be allowed afterwards to shrink
back from fair discussion on philosophical prin¬
ciples.”
It is wiser and safer, as well as more pious and
humble, and more agreeable to Christian truth, to
confess, that, of the mysteries which have been so
boldly discussed by many who acknowledge them
to he unfathomable, we know nothing beyond
the faint and indistinct revelations of Scripture ;
and that if it had been possible, and proper, and
designed, that we should know more of such mat¬
ters, more would have been there revealed.
And we should rather point out to objectors
that what is revealed, is practical, and not specu¬
lative :—that what the Scriptures are concerned
with is, not the philosophy of the Human Mind
in itself, nor yet the philosophy of the Divine
Nature in itself, but (that which is properly
ligion) the relation and connection of the two
Beings;—what God is to us,—what He has done
and will do for us,—and what we are to be and to
do, in regard to Him.
How great must be the error sarising from men’s
overlooking, or not carefully attending to, this
circumstance, it is hardly necessary to point out.
The rustic, who persists in maintaining that the
sun itself actually moves, because he sees it rise
and set, i.e. sees that it is in different positions
relatively to himself; and the child, who, while he
is sailing in a ship, fancies that the land flies from
him, or advances towards him; are not more com¬
pletely mistaken in their notions, than those theo¬
logians who reason upon the accounts which the
Scriptures give us of the Deity, as if these were
intended to explain to us what He is, absolutely,
in Himself, and not merely what He is in rela¬
tion to ourselves.
And the liability to error is greatly increased
by this circumstance; that even the relations in
which God stands to his creaturesare so imperfectly
comprehensible by our understandings, that it is
necessary to explain them by analogical language,
and by the use of such types and comparisons, as
may furnish to our minds a kind of picture or
image of heavenly things, whose correspondence
with the original cannot of course be in all points
complete ; any more than a picture can, in all
respects, resemble the solid body which it is de¬
signed to imitate. If, therefore, we extend the
analogy further than was intended, and conclude,
that the things which are represented as corre¬
sponding in some points, must needs correspond
throughout,—or if, again, we conclude, that the
things must be alike, because they are analogous,
and bear similar relations to something else,—
we shall fall into the grossest absurdities; such
as we often see in children, when they interpret
literally the analogical explanations which are
given them.
If any one will be at the pains to collect in¬
stances for himself, from recollection of his own
infancy, and from what he has observed in other
children, of the mistakes which are in this way
continually committed by every child, and will
carefully reflect on these, not as a mere source
of amusement, but with a view to his own in¬
struction, they will serve as a mirror to shew
what sort of mistakes he himself also has to guard
against, in the notions he forms respecting the
Almighty.
To take one out of innumerable instances; how
many there are who speak and reason concern¬
ing the glory of God (that being a phrase which
occurs in Scripture), as if they supposed, that the
desire of glory did literally influence the divine
Mind, and as if God could really covet the admi¬
ration of his creatures: not considering that the
only intention of this expression is to signify
merely, that God’s works are contrived in the
same admirable manner, as if He had had this
object in view: and that we are bound to pay
Him the same reverent homage, and zealous obe¬
dience, as if He were really and literally capable
of being glorified by us. And yet it is chiefly
from a literal interpretation of this phrase of
“ the glory of God” that some Divines have un¬
dertaken to explain the whole system of divine
DISSERTATION THIRD.
519
Providence, and to establish some very revolting
and somewhat dangerous conclusions.
The difference between Religious knowledge
properly so called, and what may be more pro¬
perly styled theological Philosophy, may be thus
illustrated. Different theories, we know, have
prevailed at different times, to account for the
motions of the planets, and of the moon, and other
heavenly bodies,—the tides, and various other
subjects pertaining to natural philosophy. Seve¬
ral of these theories, which supplanted one an¬
other, have now become obsolete; and modern
discoveries have established, on good grounds,
explanations of most of these points. But the
great mass of mankind cannot be expected to
understand these explanations. There are, how¬
ever, many points of daily practical use, which
they can understand, and which it is needful for
them to be informed upon. Accordingly, there
are printed Tables, showing the times of the sun’s
rising and setting at each period of the year,—
the appearances of the moon,—the times of
eclipses,—the variations of the tides, in different
places, and the like. And all these are suffi¬
ciently intelligible, without any study of astrono¬
my, even to plain unlearned men. The practical
knowledge thus conveyed involves no astronomi¬
cal theory, but may be equally reconciled with
the Ptolemaic or the Copernican systems of the
universe. It is not the less possible, nor the less
useful, for any one to know the times when the
sun gives light to this earth, even though he
should not know Avhether it is the sun that moves,
or the earth.
Now it is just such practical knowledge as this
that the Scriptures give us of the Christian Dis¬
pensation. They afford practical directions, but
no theory. But there is this important differ¬
ence between the two cases. The human facul¬
ties could, and at length did, (though it is beyond
the great mass of mankind,) discover the true
theory of the appearances and motions of the
heavenly bodies. In matters pertaining to
divine Revelation, on the contrary, though there
must actually he a true theory, (since there must
he reasons, and those known to God Himself, even
if hidden from every creature, why He proceeded
in this way rather than in that,) this theory
never can be known to us; because the whole
subject is so far above the human powers, that
we must have remained, but for Revelation, in
the darkest ignorance concerning it. Many
curious and valuable truths has the world dis¬
covered by philosophy, (or as our translators ex¬
press it “wisdom;”) but “the world” (says Paul)
“ by wisdom knew not God:" of which assertion
the writings of the ancient heathen philosophers,
now extant, afford sufficient proofs.
And, we would further remark, that if it had
been possible and allowable for us to follow up
by metaphysical researches, the view opened to
us by Revelation, and thus to enlarge our know¬
ledge of God’s dealings with Man, Paul (as well
as the other Apostles) would not have censured,
but favoured, such researches, and would have
set us the example of so speculating. And if he
had done this, even in those discourses of his
which are not recorded in writing, we may be
sure that his Gospel would not have been con¬
sidered as “foolishness” by the Greeks, even
those of them who did not fully agree with him.
This, therefore, supplies a useful practical rule
in judging of anything we may read or hear :
whenever we meet with such a representation of
Christianity as would not have been a stumbling-
block to the Jews, or such as would not have
been foolishness to the Greeks, we may at once
conclude that this cannot he the Gospel which
Paul preached. For he would not have been
opposed as he was, had his doctrine favoured
either men’s pride and worldly ambition, or their
spirit of presumptuous speculation.
It may be remarked, as another reason for con¬
demning such presumptuous explanations, and
metaphysical theories of Christianity, as we have
alluded to,—all of them equally,—that if such
speculations be allowed, it is evident Christianity
must be, not one, but two religions;—that for
the few profound theologians, and that for ordi¬
nary men; such as the humble shepherds to whom
the holy Angels announced the birth of Jesus,—
the fishermen and publicans who associated with
Him,—and “the common people” who (we read)
“ heard Him gladly.” Nowthere isnothing more
characteristic of the Gospel Dispensation than
its oneness ;—one Lord,—one faith,—one hope,
—in short, one and the same religion proposed
to all who will heartily receive it.
520
PRELIMINARY DISSERTATIONS.
All such speculations, then, we should reject, if
we would (in the words of the Apostle Peter)
“desire,as newborn babes,the sincere (aboXov,un¬
adulterated) milk of the Word, that we may grow
thereby.” If we would learn the very gospel
which the Apostles taught, just as it was received
by their hearers, we must in heart and spirit ac¬
company the simple shepherds in their visit “ to
Bethlehem, to see” (not what human philosophy
has devised, but) “ what the LORD hath made
known to us.”
IV. Many corruptions, again, of Christianity
have been either introduced, or favoured and kept
up, by moral corruption in the members of Chris¬
tian Churches. For it belongs to the true Gospel
to purify and also to elevate the moral character.
Hence, there is a complete and constant opposi¬
tion between genuine Christianity and all the
evil and base propensities of man’s nature. This
is what Paul means when he says, “ Walk in the
Spirit, and ye shall not fulfil the lusts of the
flesh ; for the flesh lusteth against the Spirit, and
the Spirit against the flesh; and these are con¬
trary the one to the other, so that ye cannot do
the things that ye would:” that is, he who has
within him two contrary tendencies, cannot at
the same time yield to both.1
Every kind of depravity or moral defect, there¬
fore, predisposes men either to reject Christianity
altogether, or else to introduce, or to accept, some
erroneous views of it. And there is no kind
of religious corruption against which men are
usually less on their guard. They are well aware,
indeed, that there is a danger of men’s falling
into sin in violation of the precepts of religion.
And they are not ignorant that a religion which
is altogether/aZse may have a bad moral effect on
the worshippers. But they consider that a man
who has embraced a true Faith, and who is of a
religious disposition, wall necessarily be made, by
his religion, a good moral man; or at least such a
man as will be accepted as righteous by the God
he worships.
Now, this is true, only if we suppose him to
observe diligently the caution of Paul, “that they
who have believed in God should be careful to
maintain good works.” (Tit. ii. 14, and iii. 8 ;)
“ giving all diligence,” (2 Pet. 1. 5) (as Peter ex¬
horts us), to add to his faith, virtue, &c. But if he
takes no vigilant pains in the improvement of his
moral character, the result will be, that, instead
of his religion improving his character, his moral
deficiencies, on the contrary, will tend to corrupt
his religion. The rain itself, which falls pure from
the heavens, will not continue pure if it be re¬
ceived in an unclean vessel.
And this kind of corruption took place—as has
been above said—even in the days of Paul; who
speaks of some, “ who having cast away a good
conscience, concerning [the] Faith, have made
shipwreck.” (1 Tim. i. 19.)
It will be sufficient to mention some of the prin¬
cipal errors of this class, that have crept into the
Church, without entering into a full examination
of any of them.
ls£, The notion that a Priest has power to for¬
give sins as against God is evidently a doctrine
very acceptable to such persons as have a sense
of religion, combined with a great dislike to the
practice of Christian virtue ; and who, accord¬
ingly, are glad of any contrivance for being reli¬
gious without virtue.
‘Idly, The same may be said of the doctrine,
that fasting and other penances,—or pilgrimages
to certain holy places,—or prayers and sacrifices
offered up in behalf of the deceased,—or rich gifts
bestowed on the Church, can atone for sin, and
help to obtain for a man final salvation.2
3dly, Of a like nature is the doctrine, that if
a man who has led a thoroughly unchristian life
shall on his deathbed receive the Lord’s Supper,
or the rite of “Extreme Unction,” professing sor¬
row for his sins, and faith in Christ, we are au-
1 T«Ztol ss liXXriXoti fi»Tt»iiTou, "vet fx.b, oi av tfiXtin, naZrot. rowri. Gal. v. 17. More exactly translated—a these are so op
posed to each other as to be an obstacle to your doing what ye desire to do.” _
By the expressions which are rendered “ flesh,” and “ fleshly lusts,” and “ a carnal mind, which is enmity against God,
Paul does not mean merely sensuaZ excess, but all evil dispositions of the natural man. For he expressly charges the Corin¬
thians with being “ carnal” on account of their “ strifes and divisions.”
2 It is very remarkable that in all religions either devised by men, or corrupted by human inventions, there is a tendency
to set aside certain particular seasons, or particular persons, for what is called “ mortification,”—that is, self-torture, as a
kind of set-otf against the toleration of general licentiousness at other times, or in other persons.
DISSERTATION THIRD.
521
thorised to pronounce, that (supposing his profes¬
sions to be, at the moment, sincere) his salvation
is certain.
Now, the utmost that Scripture can warrant, in
such a case is, that we are not forbidden to hope.
But the Scripture-promises are all made to those
who “ bring forth fruits meet for repentance.”
And any one who presumes to hold out confident
promises where Scripture does not, is evidently
guilty of, preaching, not the true Gospel, but one
of man’s invention.
4:thly, The heresy of the ancient Gnostic An-
tinomians has been already alluded to, as being
held in such detestation by the Apostles. And
some Antinomian doctrines much like theirs have
been found in every Age of the Church.
For example, That because “ by grace we are
saved through faith, and that not of ourselves, but
by the gift of God,” (Eph. ii. 8,) and “ without
the works of the Law,” therefore, we may safely
“ continue in sin that grace may abound,” (Rom.
vi. 7;) that certain persons may know and feel
themselves set apart as “ God’s People,” and that
these are certain of salvation, though continuing
in the practice of known sins, because God will
not impute sin to them, do what they will; and
that they ought not to be at all uneasy at any sins
they may commit, because He purposely suffers
“ his own people to fall into very grievous sins,
in order to show them their own weakness, and
to humble them ! ” though in reality such a doc¬
trine is calculated to puff up a man with spiritual
pride, in addition to all his other vices; since
nothing is more flattering to a proud heart than
the notion of being privileged to do .without cen¬
sure, or without danger, what others would be
condemned for.
All these shocking absurdities, so utterly at va¬
riance with Scripture, have found their way into
Christianity through the depravity of Man. And
when we consider, that besides the mischief done
by such teachers to their own followers, they
bring a scandal on Christianity itself, we cannot
wonder at the abhorrence shown by the Apostles,
of the Antinomians of their own day. They
raised a prejudice against the Religion, as being
far worse than no religion at all; because the
doctrine they taught tends to silence the sug¬
gestions and the reproaches of natural con-
DISS. in.
science, and represents God as the encourager
of vice.
bthly, Besides these avowed Antinomian doc¬
trines, there are others which are liable to be so
understood as to lead practically to the same con¬
sequences ; though these consequences are not
designed or foreseen by those who incautiously
teach such doctrines. For example, there are
some good, well-meaning men who represent
Paul as describing, in his Epistle to the Romans,
(chap. vii. 9-25,) his own actual condition. If
they would read the whole chapter through, (es¬
pecially verse 9,) and then go on to the eighth
chapter, they would see that this is impossible;
and that the Apostle is evidently describing the
condition of a man under the Law, and not under
the Gospel — sensible of the requirements of
God’s Law, but not under the influence of the
Grace of the Gospel.
Now, any man who is living a life of gross
vice, while he approves and admires virtue, will
not be likely to be at all alarmed, or to consider
moral reformation as needful, or indeed as pos¬
sible, if he believes himself to be just in the same
condition with the Apostle Paul, and all the
other most eminent Christians that ever existed.
And he will be likely to regard all that is said
in Scripture about holiness of life, as a kind of
theory which no one is expected to bring into
practice.
Again, the doctrine that “ nothing a man can
do can forward his own salvation,” is indeed true,
in the sense that no good works of ours can
establish a claim of merit in God’s sight; and also
in this sense, that we cannot lead a life of true
Christian virtue, of ourselves, and without the aid
of the Holy Spirit, which “ helpeth our infir¬
mities.” But if the doctrine is earnestly and con¬
tinually taught without these explanations, the
greater part of the hearers will understand it in
a sense exactly opposed to Paul’s exhortation, to
“ work out our own salvation with fear and trem¬
bling;” and they will also conclude, that if to keep
God’s commandments carmot further a man’s sal¬
vation, to break them cannot hinder his salvation.
At least, the Christian is not incited to endeavour
to “ grow in grace,” and to “ go on unto perfec¬
tion.” And thus the doctrine becomes, in its
consequences, completely Antinomian.
3 U
526
PRELIMINARY DISSERTATIONS.
ready to consent to anything for the sake of peace
and unity.
(2.) And thus they are led to commit the second
of those mistakes above adverted to, and to re¬
sist all correction of abuses, for fear of unsettling
men’s minds, disturbing the peace of the Church,
and violating its Unity.
And this is especially the case when men have
adopted that view of Christian Unity which re¬
presents it as consisting in having one commu¬
nity on earth, to which all Christians belong, or
ought to belong, and to whose government all are
bound to submit.
It is true, the same kind of feeling may influ¬
ence the members of any Church, even one which
does not claim to be “ the universal church.”
For men are undoubtedly bound to be very care¬
ful not to “ cause divisions” hastily, or on slight
grounds. Whatever Christian Church they find
themselves belonging to, they are bound to give
no occasion of any schism—any unfriendly sepa¬
ration from it, unless they are fully convinced
on deliberate reflection that its doctrines or prac¬
tices are at variance, in essential points, with
Scripture, and that there is no reasonable hope
of reform. But, on the other hand, if the rulers
of any Church, force a part of its members to se¬
parate from it, by maintaining what is really thus
unscriptural, (and of this the All-Wise God alone
can be the infallible judge,) the guilt of the schism
lies with those rulers.
The questions, however, what is or is not Scrip¬
tural \ and what points are essential X are to be
very carefully and candidly considered, under a
sense of awful responsibility to God; and are
questions on which different men often come to
different conclusions.
And hence, while some are guilty of hastily
causing divisions on wrong grounds, or on insuf¬
ficient grounds, (as if each man were free to con¬
sult his own fancy or convenience in such mat¬
ters,) others sometimes fall into the opposite ex¬
treme. For there are persons who will bring
themselves to acquiesce in something which they
perceive to be fundamentally wrong, for fear of
being guilty of causing a schism.
Now this latter fault, men are much more liable
to, who consider “ the true Church” to be, ne¬
cessarily, one community under a single govern¬
ment on earth. For all Christ’s promises being
made to his Church, they feel that a separation
from that community which they regard as the
Catholic Church, would be to renounce the Gospel
Covenant. And thence they are led to infer,
either that Christ allows this Church to depart
in important points from the written Word, or
else that what plainly appear to he departures
from it, are somehow reconcilable with it. They
would, perhaps, be glad if the governors of their
Church could be prevailed on to remedy such
and such an abuse. But if these resolve, in com¬
pliance with the wish of the majority, to retain
it, such persons consider that they have only to
submit, rather than forfeit (as they imagine) all
their Christian hopes at once. To oppose or
question the decisions of the Church which they
regard as the divinely-appointed Authority and
Guide for all Christians in whatever pertains to
religion, they consider as a rebellion against
Christ. And thus they in time force themselves
to believe their Church infallible—to assent to
and uphold the grossest corruptions—and to re¬
sist all attempts at correction.
This mistake as to the nature of Christian unity
is one which could hardly arise in the days of the
Apostles. For they manifestly founded many dis¬
tinct Churches, agreeing indeed in Faith, but
quite independent of each other, and having no
common Head on Earth. And the Bishops which
they appointed for the government of most (if
not all) of these Churches, differed as much from
the Bishops of later times, as a Sovereign prince
does from a colonial governor. Each was the
Head Presbyter, to whom was intrusted the chief
power in an entire Church.
It was indeed allowable and desirable that de¬
legates from these several Churches should as¬
semble, from time to time, to hold a Council, (or,
as it is called in political affairs, a CWyrm,) for the
purpose of conferring together on religious ques¬
tions, and concerting measures for putting down
false doctrines and abuses. This did not neces¬
sarily destroy the independence of the Churches;
any more than Sovereign-States surrender their
independence when they send ambassadors to a
Congress to deliberate concerning a treaty. But
ambitious men, when they obtained a majority in
any of these Councils, naturally encouraged the
DISSERTATION THIRD.
527
notion that the minority were bound to submit
to their decisions, whether they would or no.
This, so far, tended to combine all these Churches
into one. And when the chief part of the Roman
Empire became Christian, the Emperors always
sought to favour this combination, in order that
they might the more easily and the more com¬
pletely control it.
And that this worldly policy of theirs had a
principal share in the uniting of the several dis¬
tinct Christian communities into one, is plain
from the circumstance that it was not Jerusalem
—the earliest Christian Church, and from which
all others were off-sets—but Rome, the political
Capital of the Empire, that came to be regarded
as the seat of government, and centre of the Uni¬
versal Church.
There is not, indeed, any rule laid down by di¬
vine authority, as to what is to be the greatest
extent of a single Church. It cannot, therefore,
be said that there is in Scripture any direct pro¬
hibition of Christians all over the world uniting
themselves into one single community. But the
example left us by the Apostles, in founding many
distinct Churches, independent of that of Jeru¬
salem, and of each other, shews that they did not
consider a very extensive Church, as either a ne¬
cessary or a desirable thing.1 And the incon¬
venience is so manifest and so great, of placing
under one Church-government men of different
nations, far distant from each other, and differing
in language and in customs, that we may be sure
no such thing would ever have been thought of,
except either for reasons of worldly policy, or
else from a misconception of the character of
Christ’s kingdom. The ruler of a great empire,
containing many provinces, may naturally wish
that all his subjects should be members of the
same Church ; and the supreme rulers of any
Church are likely to be tempted by ambition to
extend that Church as widely as possible. Those,
again, who make the mistake above alluded to, re¬
specting the true meaning of christian-unity, will
readily enter into these views. And some will
be likely to fancy that the governors of a single
Church comprehending all Christians, will be
likely to prevent such errors as might spring up in
some out of a multitude of independent Churches,
and thus preserve the purity of Gospel truth. But
this is to suppose that the governors of the uni¬
versal Church are to be infallible. Else, it is
plain that they may fall into error as easily as the
governors of a smaller Church, and may employ
their extensive power in maintaining and spread¬
ing such error. And, accordingly, all who con¬
tend for a Universal Church, in the sense of a
single community under one government on earth,
always lay claim,—more or less distinctly,—to
infallibility as belonging to that Church.
But as no such infallibility can be proved, or
does exist, the result has been that all attempts to
give universal dominion to a single Church have
increased the difficulty of checking and of cor¬
recting corruptions.
For example—one great abuse, and that the
parent of many others, the keeping of the Scrip¬
tures and of the public Service in a dead lan¬
guage, was doubtless much favoured by the great
extent of a single Church. The abuse was not
one that originated in very early times. For
it was not caused by men’s having from the first
a superstitious dread of any attempt to trans¬
late the Scriptures at all, and consequently leav¬
ing them in the original Hebrew and Greek. On
the contrary, they were translated into Latin,
when that was the prevailing language, on pur¬
pose that they might be accessible to the people.
And afterwards, when Latin gradually ceased to
be spoken in the Provinces, and at length, in
Rome itself, the Latin Bible and Prayer-Books
continued in use after they had ceased to be un¬
derstood by the mass of the people. No one could
point out the precise time when a new translation
first became necessary; because the change of
Latin into Italian, Spanish, &c., was gradual.
And men had a sort of superstitious veneration for
the language which they and their fathers had
been accustomed to hear employed in divine
Service.
And this is evidently an error which it served
the purpose of an ambitious Church to keep up.2
All over the world, as far as the dominion of that
1 Not only were there several distinct Churches in the one province of Macedonia, and in that of Achaia, hut the one
2 t 6 t0 the Galatians is addressed to “ the Churches" of Galatia.
, e^orcement of celibacy on the clergy, (for which there is no warrant in Scripture,) was also manifestly favourable
e am itious views of a supreme central government, as it tended to keep the clergy unconnected with the people.
524
PRELIMINARY DISSERTATIONS.
to dictate to the understanding, and to domineer
over the conscience, of all the rest. For, what¬
ever strong reasons a man may see for condemn¬
ing any corruptions which that Church may have
sanctioned, he will labour to stifle his convictions,
and to believe any absurdity, or approve of any
abuse, rather than exclude himself, as he sup¬
poses, from the true Church. So also, a mistake
as to the true limits of Church-authority is one
which tends to foster other mistakes. If a Church
assumes the right of setting aside the precepts of
Scripture, or of giving any interpretations what¬
ever of them to suit its own views, or of “ mak¬
ing the Word of God of none effect through their
tradition,” a man will be led to submit to all this
against his better judgment, if he is persuaded
that he is only submitting to the authority which
Christ has appointed for his guidance in all that
pertains to religion.
And lastly, the prevalence of this error leads
to the neglect of the study of the Scriptures, and
even to their being left untranslated, and inacces¬
sible to the People. For as no one need study
medical books, himself, if he is placed under the
care of a skilful physician, so there seems no need
for any one to study Scripture, if he has others
to do it for him, whose interpretations, after all,
he is bound to receive, and who are ready to tell
him what he is to believe and do.
And thus general ignorance will soon prevail;
which is the greatest encourager and supporter
of every kind of error and abuse. For when the
light of the Gospel which was given for the illu¬
mination of the World, is thus “put under a
bushel,” men are thenceforward left to grope in
darkness, without any means of distinguishing
truth from falsehood, or genuine Religion from
the grossest superstitions.
REFORMATIONS IN RELIGION.
We have seen that corruptions of Christianity
have existed, from the days of the Apostles,
downwards ; and that these inspired teachers
warned men to be on their guard against this
danger. They exhort us to “ take heed to
ourselves,” on account of “ deceitful teachers,”
and to “ prove all things, and hold fast that
which i£ right.” Christians, then, are evidently
bound to be carefully watchful against any cor¬
ruption of the “ simplicity of the Gospel.” And
whenever they shall find that any unscriptural
doctrines or practices have crept in, it is their
duty to exert themselves for the correction of
the evil. And, accordingly, it appears that al¬
most every one of the corruptions which have
prevailed in Christian Churches, was opposed,
more or less, at its first introduction. Yet, on
the whole, this opposition was, for many centuries,
so far ineffectual, that the religion of the greater
part of the Christian world degenerated more
and more from its original purity.
It is not our design to give an account of the
various attempts made (with or without success)
to resist the introduction of corruptions, or to
drive them out. It will be sufficient to point
out:
I. What are the principal hindrances that
have stood in the way of a successful opposition
to errors and abuses, and of needful reforma¬
tions.1
II. What are the faults that reformers are
chiefly liable to, and against which, consequently,
men ought to be especially on their guard.
[I.] There are three mistakes frequently com¬
mitted by Christians, each of which has contri¬
buted to prevent successful opposition to corrup¬
tion, and correction of them.
1 In modern language one sometimes hears of “ reforming abuses.” But this is an impropriety. It is an institution that
is reformed: abuses are to be remedied.
DISSERTATION THIRD.
525
(1.) Some have attached too much importance
to matters not essential, and have contended too
earnestly about them.
(2.) Others—and sometimes, indeed, even the
very same persons—have acquiesced in very seri¬
ous corruptions, through a mistaken anxiety for
what they consider Christian Unity and concord.
(3.) A third cause, tending to the same effects,
is a mistaken dread o innovations. Those who
are on their guard only against sudden corrup¬
tions, and overlook such as creep in silently and
gradually, wil be disposed to resist as innova¬
tions what are, in truth, restorations ; and to
maintain what are, in reality, very great and
mischievous innovations.
(1.) When men are once engaged in a contest
on any question, their eagerness is apt to increase
as the debate goes on; and they often come to re¬
gard some matter that is reallyof very small conse¬
quence, as if it were of the greatest. Thus, their
attention is often drawn off from things far more
important. For example, there have been fierce
controversies among Christians about the proper
time for celebrating the festival of Easter. And
this is one of the many cases in which the at¬
tempt to unite all Christians under the govern¬
ment of one single community on earth, has led
to discord instead of concord. For, it is necessary
that in any one Church, the times for celebrating
religious festivals, should be fixed by authority ;
however unimportant it may be what shall be
the time fixed. But two or more independent
Churches may differ in this, and in several other
non-essential points, without hostility and strife.
Such questions, however, immediately become a
source of strife, as soon as it is thought necessary
to unite these Churches into one. And the same
maybe said of that most bitter dissension which
arose between the Eastern and Western Churches
as to the use of leavened or unleavened bread at
the Lord’s Supper. And at the very time when
these controversies about such comparatively in¬
significant points were raging with the utmost
fury, the unscriptural practice of applying to the
Virgin and other saints as mediators, (besides
many other superstitions,) was spreading widely
among Christians.
So also, in later times, and even in our own
day, there have been vehement debates on the
question, whether a clergyman should preach in
a black dress or a white one. And the attention
of many persons has thus been called off from
the far more important question as to the sound¬
ness of the doctrine preached. While occupiec7
about the colour of a vestment, they have over
looked the serious corruptions of the faith intro
duced by such as were “ teaching for doctrines
the commandments of men.”
And, again, the schism of the Donatists, which
gave rise to one of the most furious contentions
that ever existed among Christians, originated
merely in a question as to the regularity of the
appointment of a certain bishop.1 These persons
having taken up that notion respecting “ aposto¬
lical succession” which has been noticed in a
former part of this Dissertation, they would not
allow that the ministers ordained by the bishop
whose succession they disputed, were ordained at
all; or that any whom these baptized were really
Christians, &c. And while this fierce contest
lasted, which was nearly two centuries, (from the
fourth to the sixth,) men’s attention was drawn
off by it from essential points ; and various cor¬
ruptions were allowed to spread, unchecked and
unnoticed. Moreover, one effect of such contests
is, that many men are apt to become, at length,
so weary of strife, as to be ready to purchase
peace at any price, and to acquiesce in various
abuses and errors in important points, rather than
run the risk of exciting any controversy.
Now we ought certainly to prefer peace and
Christian concord to everything except the essen¬
tials of Gospel-truth and pure worship. But
these must not be given up even for the sake of
peace.
For, religious agreement is not that Christian
concord which it is so important to aim at. un¬
less it be agreement in the Religion of the
Gospel. There may be an agreement in error as
well as in truth.
But, vehement and long-continued disputes
about matters of minor importance which are
not worth so much contention, will often drive
men into the opposite extreme, and make them
1 Csecilian, elected Bishop of Carthage, 311.
522
PRELIMINARY DISSERTATIONS.
Again, some teach that Christ’s obedience to
the divine law is imputed to believers in Him; so
that the good works He performed are reckoned
in God’s sight as performed by them. This doc¬
trine, though not warranted by Scripture,1 is
taught by some who are themselves striving to
lead a virtuous life. But their hearers will be
likely to conclude, “ if Christ’s suffering for us
and in our stead, is to exempt us from suffering
in our own persons, then, by parity of reasoning,
his performing in our stead good works which
are imputed to us, as if we had performed them,
must exempt us from all need of keeping God’s
commandments ourselves.” And though this
may not be an inevitable conclusion, and explana¬
tions may be given which will avoid it, still, we
may be sure that there vAll be a danger of men’s
drawing such an inference. And for this danger
those teachers will be responsible who set forth
a doctrine not clearly taught in Scripture.
And some there are who dwell exclusively on
the efficacy of faith; teaching (which is quite
true) that genuine Christian faith will not fail
to bring forth the fruit of a Christian life. But
if they do not at the same time teach, as our Lord
and his Apostles do, the necessity of “ running,"
—“striving,"—“ watching—being “careful"
(1 Cor. ix. 24; Luke xiii. 24 ; Mark xiii. 33-37,)
in their Christian course, their hearers will con¬
clude that they have only to take care of their
faith, and leave Christian virtue to follow of itself.
And being once convinced that they have em¬
braced the true faith, they will feel themselves
in the condition of a man who has embarked on
board a safe ship, bound to the right port, who
has nothing to do but sit still, and let himself be
carried thither. And the consequence of their
thus taking no pains or care in the moral culti¬
vation of their mind, will be, (as has been ob¬
served above,) that their religion, instead of im¬
proving their moral character, will be itself cor¬
rupted by it; and having “ cast away a good con¬
science, they will make shipwreck of the faith.”
(1 Tim. i. 19.)
The above are a part, and only a part, of the
religious corruptions which have been introduced
or fostered by moral corruption.
Y. Lastly, worldly policy has greatly helped
to promote some of the worst religious errors.
The same kind of men who would, most of them,
have opposed Christianity, from covetous or am¬
bitious views, when it was first preached, were
disposed, afterwards, to distort the religion so as
to suit those views.
Thus, any worldly men who found their way
into the Ministry, were tempted to favour any
kind of superstitious error that tended to bring
them profit and power. The People were often
disposed to fancy that the Priests could serve
God in their stead, and that there were mysteries
in Religion which the Priests understood, but
which the Laity need not know anything of, and
ought not to inquire into. And hence they were
ready to follow blindly the guidance of the
Priests in religious matters ; just as a man trusts,
in legal concerns, to his Lawyer, and in medical
concerns, to his Physician; doing what they
direct, and not considering it necessary himself
to study Law or Medicine.
All these, and many other such erroneous
notions, have been encouraged by worldly-minded
Priests for the increase of their own power and
wealth.
Again, ambitious and worldly-minded Rulers
are generally glad to make use of Religion as an
instrument for securing the submission of the
People to tyrannical oppression, and for aiding
their ambitious views when they seek to subdue
their neighbours, under the pretext of propagat¬
ing the true Faith. Such men are disposed, like
the Jews of old, to “ take Jesus by force to make
Him a King that is to make his a “ kingdom
of this world.”
Such men perceive a political advantage in
having the same religion professed by all their
subjects ; and they endeavour to secure this ob¬
ject by force. They make laws for the punish-
1 Our Lord seems to be expressly guarding against this notion in the parable of the Marriage-feast. The Wedding gar¬
ment (which represents the u righteousness of Christ,”—that is the moral character which his Spirit enables us to attain to)
was provided according to the Oriental custom—by the king. But the guest who had refused to put it on was cast out
without being allowed to plead—“ You are clad in the wedding garment; your wearing it may be imputed to me, and may
serve instead of my putting it on.”
DISSERTATION THIRD.
523
ment of heretics : or to exclude from civil rights
every one who is not a member of their Church ;
or they seek to compel every one to have his
children taught their Faith.
All these are so many different forms in which
the spirit of PERSECUTION shows itself, in vary¬
ing degrees of violence.
Now, it is of course most desirable that all men
should agree in true Christian faith and practice.
But then,- this profession of the Religion should
be sincere and voluntary. It is utterly contrary
to the spirit of Christ’s religion to attempt to
maintain or to propagate it by force. But it be¬
longs to the “ natural man” to feel jealousy and
dislike of those who differ from us in opinion on
important points ; and, when we fail to convince
them, to wish to force them to submission; or at
least to keep for ourselves what is called a “ poli¬
tical ascendancy” over them. And those who
have a zeal for what they consider true religion,
but who are strangers to the genuine spirit of the
Gospel, persuade themselves that they are seek¬
ing God’s glory and the good of mankind, in car¬
rying out their own intolerant principles. Since
Governments, they say, ought to seek the good,
—universally,—of the subjects, and true religion
is the greatest good, it must be the duty of the
Civil Magistrate to insist on his subjects adher¬
ing to a true religion.
But they overlook two circumstances: 1st,
that since the Magistrate must, by this rule, be
himself the judge what religion is true, it would
follow that the Jewish Rulers had a right to forbid
the Apostles to preach the Gospel; and that the
Apostles were bound to obey; and, 2dly, that
though the sincere acceptance of true religion be
the greatest good, an outward profession, in obe¬
dience to the laws, of what a man does not really
believe, is no good at all, but a great evil.
Yet all this is overlooked by those who “ have
a zeal towards God, but not according to know¬
ledge” of the true Gospel.
In addition, however, to mistaken religious
zeal, there can be no doubt that men’s minds are
often biassed towards this particular corruption
of Christianity, by worldly policy. The love of
power and worldly pre-eminence helps to give
their turn to their religious zeal. And thus they
so far mistake the real character of Christianity,
as to imagine it allowable, and even a sacred duty,
to put down religious errors by force, or to secure
a monopoly of civil rights in behalf of the mem¬
bers of their own Church.
The above, then, are the chief sources from
which corruptions of Christianity have sprung.
And they correspond to those from which, as we
have seen, originated the chief part of the early
opposition to the religion, viz.: mistaken adhe¬
rence to the Mosaic Law; superstition ; misap¬
plied philosophy; moral depravity; and worldly
policy.
As for the means by which various religious
errors have been kept up and spread, one of the
principal is that employment of coercion which
has been just noticed. As a general rule, a re¬
sort to restrictions, and to force of every kind,
must be, on the whole, more favourable to error
than to truth, in all subjects : because it tends to
take away the great advantage which truth has
over error. Truth being in itself stronger than
falsehood, may be expected to gain a superiority
when there is free discussion. But Laws and Pe¬
nalties may be on the wrong side as well as on the
right. Those, therefore, who resort to these, may,
not unfairly, be presumed to have themselves,
some distrust of the goodness of their cause, since
they remove the trial from a Court (that of Rea¬
son) in which truth has an advantage over false¬
hood, and appeal to brute-force, in which truth has
no such advantage. A fair and free trial is what,
generally speaking, the intelligent advocates of
truth, in all subjects, will be likely to call for,
and the advocates of error, to deprecate. More¬
over, in regard to religious questions, the resort
to coercion proves a person to have totally mis¬
taken the character of Christianity as to one most
important point; so that there is a probability
that he will have mistaken other points also.
That erroneous view, again, of Christian Unity,
which has been already noticed, has tended very
much to keep up and to extend other errors. For
if a man is once convinced that all Christians
are bound to belong to some one Community on
earth, he will dread nothing so much as-separa¬
tion from that Church, whatever it may be, which
he considers as having the best claim to be that
one community.
And thus, a majority will be enabled completely
528
PRELIMINARY DISSERTATIONS.
Church extended, the Priests had a language of
their own, not understood by the common people,
and in which alone the Sacred Books could be
studied. And thus the People could know little
or nothing of their Religion, except just what these
Priests chose to tell them.
Now it is true, indeed, that the same error
might find its way into each of several indepen¬
dent Churches, however small. It is conceivable,
for example, that independent Churches in vari¬
ous parts of the world might have retained, some,
an ancient Gothic translation of the Bible, some,
an Anglo-Saxon, &c., long after those languages
had ceased to be spoken. But then it is far less
likely that euert/ one of forty or fifty independent
Churches should persist in this error, than that
one should do so. And if some of those Churches,
or even any one of them, had made new transla¬
tions of the Bible to meet the wants of the People,
the others would have been shamed into follow¬
ing their example in a thing so evidently reason¬
able.
And this is proved by what has actually taken
place. It is well known that at the time of Lu¬
ther’s Reformation, and long before, the translat¬
ing of the Scriptures into modern languages was
most earnestly opposed by those who adhered to
the Church of Rome. The Scriptures, which were
originally addressed to Christians of all classes,
including slaves, were represented as unfit for
the perusal of the common people. But since
then, the Roman Catholics have in some measure
followed the example of those Churches which
they denounce as heretical.1 They have among
them now, (though not in perfectly free circula¬
tion,) translations of Scripture into English,
French, Italian, and other languages. And.some
of them have also Prayer-books, with the Latin
and their own language printed in parallel co¬
lumns, so as to enable them to understand the
Service that is going on.2 3 There can be little
doubt, therefore, that this would have been done
long before, if there had been all along numerous
independent Churches, such as the Apostles esta¬
blished.
It is true, indeed, that before the time of that
Reformation, and indeed, in a less degree, for a
good while after it, the prevailing ignorance was
such, that few besides the Clergy could read at
all. But then it should be remembered, first,
that to have the Church-Service—including the
reading of the Scriptures—in a language under¬
stood by the People, is a most important benefit
even to those who cannot themselves read ; and,
secondly, that this gross ignorance would not
have existed if the Clergy had all along done their
duty in presenting to the People the Scriptures
in their own language, and encouraging them to
learn to read, for the very purpose of studying
those Scriptures as they ought.
It is plain, therefore, that the abuse we have
been speaking of was left much the longer unre¬
medied in consequence of the dominion of one
Church of vast extent.
And the same may be said of many other
abuses. A reform that is evidently needed, is
more likely to be resisted by one community,
than by every one of many independent commu¬
nities. Any one out of several distinct Churches,
when it corrects something that is manifestly
w'rong, sets an example which others are not un¬
likely to follow. And this advantage is wanting,
when all or nearly all Christians are put under
one single government.
The causes above mentioned have proved, in
very many instances, great hindrances to need¬
ful reforms. Nevertheless, many attempts were
made, in the earlier Ages of the Church, to intro¬
duce errors and abuses, which were vigorously
and often successfully resisted. We have on re¬
cord many varieties of false doctrine and corrupt
worship, (most of them now nearly forgotten,)
1 This great and important change completely disproves what is maintained by the advocates, and by the bitterest enemies,
of the Church of Rome—the unchangeable character of that Church. But there is nothing so grossly and notoriously fa se
as not to gain credence, if maintained by both of two opposite parties.
3 As for the celebration of Divine Service in Latin, it has ever been made a matter of boast by the Roman Catholics, tha
in a foreign Country, a priest going thither ignorant of its language, can at once perform Service, as at home ; and that a tra¬
veller equally ignorant of the country, can attend the Service of his Church, winch is the same everywhere ; while a member
of any other communion would be at a loss. This is as if a blind man should make it a matter of boast that he is not incom¬
moded by the short days of winter, and has no occasion for candles. That day and night are alike to him, would indeed be
an advantage, if he could see in both; but not, when the case is that he can see in neither.
DISSERTATION THIRD.
529
which were generally condemned and expelled
as heretical.1
Unfortunately, indeed, it often happened that
the mode in which many of the ancient heresies
were opposed, was such as to have the effect of
giving rise to fresh heresies. But it was with
good reason that the majority of the early Chris¬
tians—and, indeed, of Christians in all ages—al¬
ways opposed (though not always wise in their
mode of proceeding) every innovation in doc¬
trine. They justly considered, that anything nevj
(in essential points) introduced into Christianity
must be wrong.
But then, they often committed the fault of
being on their guard only against sudden corrup¬
tions ;—against any innovation brought in openly
and all at once. They overlooked (as men are
apt to do in all subjects) the principle so well
laid down by Lord Bacon, that “ Time is the
greatest innovator;” that it “ introduces changes
so silently and gently as to escape notice and
that “ since things alter for the worse spon¬
taneously, hence, if they be not altered for the
better designedly, there will be no end of the
evil/’ To resolve that no changes shall take
place, is to talk idly. One might as well forbid
the winds to vary, or the tides to flow. But to
resolve that no changes shall take place except
such as are undesigned and accidental, is to de¬
termine that though a clock may gain or lose in¬
definitely, we will take care that it shall never
be regulated.
What is called “ the change of the style," is a
striking instance of a seeming innovation, which
Avas really a restoration, being a return to the
right course, by the sudden correction of a great
error that had resulted from the accumulation of
imperceptibly small ones.
In religious matters, a remarkable instance of
a gradual corruption, and a sudden reform, is
the point already noticed,—the keeping of the
Scriptures in a language unknown to the People.
This Avas a most enormous innovation; since the
Sacred Writers manifestly addressed themselves
to Christians of all ranks. But it Avas overlooked,
because it was no sudden innovation. The Latin
language Avent out of use gradually. No one
can fix the precise day or year on which a fresh
translation was first needed. But when men did
perceive the need, and translated the Bible into
modern languages, this was a great and palpable
novelty. And, as such, it was vehemently op¬
posed ; though, in reality, it was, in spirit, a re¬
storation of the original state of things ; the
placing of the Scriptures before the People in a
language which they understood.
So, also, there can be no doubt, that the change
of Christian Ministers into Sacerdotal Priests,
making offerings on an altar, and also the custom
of invoking saints, and most of the other corrup¬
tions already noticed, crept in gradually and in¬
sensibly.
The fond veneration for the memory of any
holy martyr led men to visit his tomb, and to
preserve carefully his garments, or other relics,
and also images or pictures of him. They natu¬
rally prayed to God, with these images before
them, for grace to follow the good example of
such a holy man. And thence they were gradu¬
ally led to beg for his intercession, and, in fact,
to worship him.
Then, when this had become a long-established
corruption, and when men were called on at once
to renounce it, and to pray to none but the all¬
present God, many were startled at the innova¬
tion, and resolved to keep to “the old religion,”
and to Avorship as their ancestors had done for
centuries, rejecting as heretical all new doctrines.
For, to them, the observance of the first and se¬
cond commandments was a novelty; though, in
reality, it Avas only a return to the primitive
Avorship.
And so it was, no doubt, with the greater part
of the corruptions that crept into Christianity.
1 It should be observed that a “ Heretic” properly signifies a person who maintains some false doctrine condemned by
the Church of which he is a member. Ho Church, therefore, can be, in strictness of speech, heretical, though it may be erro¬
neous. Accordingly, the Church of England, for example, pronounces the Church of Rome to have “ erred ;”bi}t does not
aPply the term u heresy” to its errors, because it acknowledges the Church of Rome to be a distinct, independent Church.
The Romanists, on the other hand, pronounce the Church of England ^ heretical,” because they reckon all Christians as
members—even though disobedient and rebellious members—-of their own Church. Those of them at least who do not, (for
there is a good deal of uncertainty on this point,) cannot maintain that their own Church is Universal [Catholic] in the
ordinary sense of the word, namely, as actually comprehending all Christians. They should rather call it “ the Church
which seeks to be Universal.”
DISS. m. 3 X
530
PKELIMINARY DISSERTATIONS.
Men were not sufficiently on tlieir guard against
them, because they came in by little and little.
And then, when correction was attempted, many
resisted it, and would not allow that these were
corruptions, because no one could point out the
precise time when they arose.
Butif welookto Scripture, and compare with
this the doctrine and practices of some Christian
Churches, it will be plainly seen that their re¬
ligion has been corrupted ; though we may not
be able to say exactly when, or by what means.
And this is the only safe course of proceeding.
For when a book, for instance, is often reprinted,
the only way to insure accuracy is to collate care¬
fully each edition with the original copy. Some¬
times this is neglected, and the second edition is
printed from the first, and the third from the se¬
cond ; and so on, down to perhaps twenty or
thirty editions. And the result has generally
been, that though each edition has but a very few
fresh misprints, and differs but very little from
the preceding, yet the twentieth or thirtieth
edition will be found, when compared with the
original, to be excessively incorrect, through the
accumulation of a multitude of small errors.
In like manner, if we would keep our Religion
pure, both from new and from old corruptions, we
must go straight to the very fountain-head itself,
and observe what is or is not agreeable to the in¬
spired Word.
[II.] From the causes, then, which we have been
speaking of, the correction of various abuses was
so much impeded and so long delayed, that
thorough Reformation (or as it might have been
more wisely called—a Restoration) became ne¬
cessary.
By the “reformation” of a Church is generally
understood & fundamental ehangevn doctrine and
worship, as distinguished from slight alterations.
And we use the word reformation in a corre¬
sponding sense, in reference to any other Insti¬
tution also. It is like the pulling down and re¬
building of a great part of a house, as distin¬
guished from the many small repairs which are
made every year by a prudent man, and the oc¬
casional small improvements he may see need for.
Those repairs and improvements he makes on
purpose that he may be saved from the far greater
cost and inconvenience of rebuilding, which is
an evil in itself, though a necessary evil when
timely repairs have been neglected.
So also, every reformation is an evil, on ac¬
count of the general disturbance and agitating
alarm it tends to produce. But this is a less evil
than the utter corruption of Christianity. And
there is no other alternative when errors and
abuses have been long suffered to accumulate, and
all timely remedies have been obstinately re¬
jected.
But many persons are led by their dread of the
evils and dangers of a reformation, to oppose it
as long as possible, and to endeavour to delay it;
not considering that the longer it is deferred, the
more violent and dangerous it is likely to be.
The principal dangers to which reformers are
liable, may be classed under these two heads :—
(1.) They are apt to feel too secure against
falling into the faults of the system they are re¬
forming. They often retain several of their for¬
mer wrong notions; and accordingly commit
some of the same errors, in substance, though in
some new shape—as those they undertook to
remedy.
(2.) And, secondly, they are apt not to be suf¬
ficiently on their guard against reactions. In
their abhorrence of what is wrong, they have often
rejected what is right along with it, and have
often rushed from one extreme to the other; not
considering that there may be two errors quite
opposite to each other, and that men in their
eagerness to avoid one fault, will often be blinded
to the danger of committing a contrary fault, that
is, perhaps, even worse than the first.
(I.) When men feel a very strong abhorrence
of any fault in the particular form in which they
have been used to see it, they are apt to feel, too
much self-confidence in reference to that fault;
and not to be on their guard against falling into
(substantially) the same fault in some other shape.
For example—the detestation felt by the early
Christians for the pagan worship of the images
of Jupiter and Juno, and other gods and goddesses,
made them feel secure against any danger of
idolatry, in a Christian Church. And this ab¬
sence of self-distrust contributed to their falling
into similar superstitions under different names,
by paying adoration to images of Beings whom
DISSERTATION THIRD.
531
they do not call gods and goddesses, but male
and female Saints.
So also, in the present case, reformers often re¬
tained some of the erroneous principles which had
led to the abuses they were correcting; and thus
they frequently themselves committed like errors,
though in a different shape.
For example, they were fully convinced that
the claims of the Church of Rome to infallibility
are unfounded. But many still clung to the no¬
tion that infallibility must be lodged somewhere
on Earth. They still thought a divine Revelation
necessarily implied an unerring guide for the right
interpretation of that Revelation.
Some of them, accordingly, fancied that there
must be somewhere, though not at Rome, an in¬
fallible Universal Church; though they sought in
vain to find any person or Body of men having
acknowledged power of any kind, over all Chris¬
tians, and entitled to represent and to dictate to
the whole Christian World.
And there are, even now, not a few persons,
members of reformed Churches, who suffer them¬
selves to be mystified by the vague and obscure
language of artful leaders, and to be deluded into
a belief in the infallibility of a certain Universal
Church, consisting of all the “ orthodox,” that
is, all those who agree in opinion with those lead¬
ers. And thus they fancy themselves bound to
receive as gospel truth whatever they are told by
those leaders, whom they regard as most pro¬
found theologians. For as muddy water is often
supposed to be deep, from one’s not being able to
see to the bottom of it, while that which is ex¬
ceedingly clear is thought shallower than it is, so,
weak men are apt to admire as very profound,
in Theology or in Philosophy, what they cannot
clearly understand, and to despise as shallow,
whatever is made very plainly intelligible.
Others, again, of those who cling to the notion
of an infallible interpreter of Scripture, have con¬
cluded that every sincere Christian, or that they
themselves, or that certain persons whom they
look up to as pre-eminently holy, do possess this
unerring guide, in the inspiration of the Holy
Spirit. Whatever is really dictated by that Spirit,
they justly concluded must be infallibly right.
And they found in Scripture promises of the aid
of that Spirit. They inferred, therefore, that
whatever occurred to their minds, after having
prayed for this spiritual aid, must be the true in¬
terpretation of Scripture; which, consequently,
all men are bound to acknowledge and submit to.
It is remarkable that most of the persons who
put forth such claims, do not pretend to exemption
from Sin, though they hold themselves to be ex¬
empt from the possibility of doctrinal error. To
suggest a doubt as to the truth of any doctrine
they maintain, they regard as questioning the
truth of God Himself. But for any man to ac¬
count himself impeccable, they consider as an im¬
pious presumption. And yet the office of the Holy
Spirit is to lead us, not only “ into all truth,"
but also into “ all righteousness for “ the fruit
of the Spirit is in all goodness, and righteousness,
and truth.” And though both are highly impor¬
tant, most persons would allow that this latter is
the more so. If a man were offered the choice,
—supposing he could not have both,—of being
completely secured, either from all mistakes in
doctrinal points, or from all sin, he would hardly
hesitate to acknowledge that the latter would be
the more valuable gift. Yet the very same per¬
sons who make no claim to unerring rectitude of
conduct, and exemption from sin, will hold them¬
selves to have attained unerring rectitude of
judgment, and exemption from error ; and will
regard any doubt on that point as a distrust of
God’s promises. And yet they are no more pro¬
mised infallibility than impeccability.
Some, however, there are who seem to think
that both in doctrinal questions and in moral
questions also, \Ro\x judgment is infallibly right;
and that though, in practice, they are liable to
go wrong, this can only be when they offend
against the dictates of their own conscience. This
is to claim a great superiority over the Apostle
Paul, and to reverse his procedure. For he says
“ I juc4?e n°f mine own self; for I know nothing
against myself;”1 (that is, I am not conscious of
any wrong ;) “ yet am I not hereby justified: but
He that judgeth me is the Lord.” He therefore
did not set up his own conscience as an infallible
standard of right and wrong.
1 Qv$tu ykg i/jiavrai rvvoiloc. 1 Cor. iv. 4.
532
PRELIMINARY DISSERTATIONS.
A circumstance, however, which is still more
remarkable, is this ; that many of those who thus
in reality lay claim to “ inspiration” and “ in¬
fallibility,” yet carefully keep clear of those
words. They do not call themselves inspired or
infallible. And yet it is plain that a man who
feels quite certain that his interpretations of
Scripture are suggested by the very Spirit which
dictated that Scripture, is, so far, claiming just
as real an inspiration as the Sacred Writers them¬
selves possessed. If he feels quite certain that
he is unerringly following an infallible guide,
he must in reality regard himself as infallible.
In this, as in many other cases, men are mis¬
led by names. They mistake for two different
doctrines what are in reality only two different
expressions of the very same.
When, however, a large portion of the Chris¬
tian World which had been under the dominion
of a single Church, had thrown off that yoke, the
danger of falling into the mistake of looking for
an infallible guide on earth was much dimin¬
ished. For those inclined to such a notion would
naturally, as long as they were under one Church,
look to that Church as the seat of the infalli¬
bility. But when they were separated into
several distinct communities, the error tended—
if one may so speak—to cure itself.
For then, several conflicting claims to infalli¬
bility were of course put forth, by persons teach¬
ing different doctrines, yet who each professed
(and doubtless often with truth) to have
earnestly prayed for inspiration ; and as it was
plain that all these claims could not be well-
founded, this naturally put men on inquiring
whether any of them were so. And then, all
sober-minded men perceived that the only proo/
of inspiration, and that which must necessarily
accompany it—the display of miraculous signs
■—was wanting in all the claimants ; and con¬
sequently, that no infallible guide on Earth has
been provided.
But the error, though greatly checked, is still
to be found among weak-minded enthusiasts,
who cannot, or will not think accurately.
It is kept up in them in great measure, by
their confounding together the infallibility of the
guide in itself, and our infallibility in following
that guide. For instance, if, on the one hand,
the mariner steers by a chart, then, even though
he conform to it quite exactly, yet if this chart
itself be at all incorrect, he may be misled by it.
If, on the other hand, he steers by a star, he is
sure that his guide cannot be wrong; but yet
he may be misled if he mistakes one star for
another. If, however, he is convinced that this
is totally impossible, and that he is infallibly fol¬
lowing an infallible guide, it is plain he reckons
himself infallible.
And even so, though the Scriptures and the
Spirit of God cannot themselves err, no one has
a right to pronounce confidently that he is ex¬
actly conforming to them, unless he is favoured
with some sensible miraculous signs from Heaven
to assure him of this. Without such a sign, “ if
we say that we have no sin”—or that we have
no error—“ we deceive ourselves.” For even if,
in some point, our judgment or our conduct be
in point of fact perfectly right, still, as we can¬
not with perfect certainty know this, during our
state of trial on Earth, we have no right confi¬
dently to claim it.
Another wrong principle which has been re¬
tained by many reformers, is that of persecution.
By the principle of persecution, we mean the
notion that it is allowable and right to use
secular coercion in religious matters, or to main¬
tain what is called the political “ ascendancy ”
of those who profess the true Faith; so that
they should monopolize civil rights and privi¬
leges.
The reason why we speak not of persecution
itself, but of the persecuting principle, is, that
where this principle is the most thoroughly car¬
ried out, there will be no actual persecution.
In any country where all who dissented from
the Established Faith have been either killed,
or banished, or compelled to conform, there is no
longer any one to be persecuted. No tree is
destroyed by the scorching drought of the African
Deserts, or by the intense frost of the Polar
regions, because no tree can grow there. And
in the most intolerant Countries on the Conti¬
nent, no heretics are burnt, because there perse¬
cution has finished its work.
And accordingly all persons agree in profess¬
ing (and generally, no doubt, with sincerity) to
be averse to persecution. Nebuchadnezzar, who
DISSERTATION THIRD.
533
condemned Shadrach, Meshech, andAbednegoto
the flames, and those Roman Emperors under
whom so many Christian Martyrs suffered, wished
them rather to save their lives by worshipping
the heathen gods. And it is the same with all,
down to this day, who hold the persecuting prin¬
ciple.
Now, that principle was not renounced by
most of the earliest Reformers. They complained,
indeed, of the persecutions they themselves were
exposed to. But this was not from any doubt
that heretics ought to be punished, but because
they denied that they were heretics. Persecu¬
tion they considered as consisting in penalties
inflicted on those who profess the true Faith,
which, of course, they held theirs to be. To put
to death such as are really heretics, was, in their
view, no persecution.
By degrees it came to be perceived, that this
principle leads to a war of extermination among
all persons of different persuasions. And men
began to adopt notions more humane, but not at
all consistent either with the Gospel, or in them¬
selves. They considered it as too severe to burn
heretics, or even to put them to a less cruel
death. But they thought it right to punish
them by fine and imprisonment, either for re¬
fusing to profess what they did not believe, or
for persisting in teaching doctrines which they
felt themselves bound to propagate. (See Acts
v. 28.)
And others, again, went further, and were for
inflicting no punishment on those who do not
hold the true Faith, but only excluding them
from the rights of citizens ; so as to secure
to the “true believers” a monopoly of civil
power.
But all these different classes of persons agreed
in the erroneous principle which goes to make
Christ’s, a “ kingdom of this world.”
Many persons imagine that there is a neces¬
sary connection between these views and a be¬
lief in the infallibility of a certain Church, and
of the impossibility of salvation out of it; as if
no one could think it right to persecute for reli¬
gious error unless he thought himself exempt
from all possibility of error; and again, as if
every one who does think this, must be a perse¬
cutor.
But this is quite a mistake. For, on the one
hand, a man may be confident that his is the only
saving Faith, and that his Church is infallible—
which was actually the case with the Churches
under the immediate care of the inspired Apostles
—and yet may be convinced, like those very
Apostles, that coercion in religious matters is
utterly unchristian.
And, on the other hand, a civil Ruler may so
far misconceive the true character of the Gospel
as to think it right to compel all his subjects to
profess what appears to him to be the best reli¬
gion ; yet without thinking his Church or him¬
self infallible in religious matters, any more than
he is infallible in secular matters. Now in secular
matters no Kings or Senates pretend to infalli¬
bility. They make such laws as they deem most
expedient, and alter them from time to time as they
see cause. But as long as those laws are unre¬
pealed, they consider themselves (and very right¬
ly) authorised to enforce them by penalties. If,
then, they regard Religion as coming under the
province of the civil Magistrate, they will of
course apply the same rule to that also. They
will feel themselves bound to take care, not only
of the persons and property, but also of the souls
of their subjects. They will prescribe what, in
their judgment, shall appear to be the best regu¬
lations for traffic, and for keeping the peace, &c.,
and also the best for Religion.
And perceiving the convenience of a uni¬
formity of Worship for all their subjects, they
will be likely to regard all who do not conform to
that which they have established, as enemies of
the State; and thence to expel or to degrade
them as politically dangerous. And thus, with¬
out making any claim to religious infallibility,
any more than to general legislative infallibility,
they will change Christ’s kingdom of Heaven
into an earthly kingdom.
It is, indeed, true that any persons whose no¬
tions in morals or in politics are such as to make
it impossible that they can be peaceable and loyal
citizens, may allowably be excluded, not only
from civil rights, but from the right of residing
at all in the Country. And if there be absolutely
no other way of fixing on such persons, but by
their professed religion, it is necessary (as long
as such continues to be the case) to submit to the
534
PRELIMINARY DISSERTATIONS,
very great evil of making their religion a test to
exclude them.1
If, for example, any one is fully convinced—
in opposition to all reason and to all experience—
that no Jews can possibly be good subjects, he
ought to urge (not that the most unprincipled of
them should be bribed by the hope of civil pri¬
vileges to profess Christianity, but) that none of
the Jewish Race should be allowed to reside in
the Country.
But to make the profession of a certain Faith
a necessary qualification for civil privileges, on
the ground that it is the true Faith, and that the
Magistrate is bound to uphold the true Faith,
and to make the Church and the State one com¬
munity, &c.; all this is evidently making Christ’s
a Kingdom of this World.
Gradually, juster views of the true character of
that Kingdom prevailed more and more both
among Protestants and Roman Catholics. But
even now, these views are far from being uni¬
versally acknowledged.
To the instances that have been noticed, others
might have been added, of the same class; that
is, instances of reformers retaining or reviving
some of their former wrong notions, or practices,
in some different shape. But what has been now
said is sufficient to shew how careful men ought
to be not to flatter themselves that when once
they have reformed a corrupt system, or re¬
nounced a corrupt Church, they are thencefor¬
ward safe from like corruptions. If the corrup¬
tions are such as have their origin in the nature
of Man, and (as is generally the case) are rather
the cause of the faulty system, than the effect of
it, it is against the infirmities of human nature
that we should the most watchfully guard.
(II.) The other class of errors formerly men¬
tioned as likely to be committed by reformers,
are those which arise from what we called the
tendency to reaction; to “ mistake reverse of
wrong for right,” and thus to rush from one
fault into another fault of the contrary extreme.
For example, many Christian doctrines having
been corrupted by “ philosophy and vain deceit,”
and mixed up with presumptuous and absurd
speculations, the result has been, that some have
been led to reject the doctrines themselves as
taught in Scripture.
Thus, the doctrines of our Lord’s divine Nature,
and of his Atonement, have been by some reckon¬
ed among the early corruptions of Christianity.
This was doubtless caused, in a great measure, by
men’s being disgusted with the rash metaphysi¬
cal explanations of those doctrines which have
been given by some who were accounted profound
theologians; and which others, equally rash, have
confounded with the doctrines themselves. And
some have even gone so far as to represent the
Apostles as having mistaken their Master’s mean¬
ing as to these points, or mixed up their own fan¬
cies with his revelations; so as to have preached
a different Gospel from what He designed, and
to have led their followers into idolatry. For, the
arrogant pretensions to a perpetual inspiration in
the Church, and its consequent infallibility, hav¬
ing been found utterly groundless, a reaction en¬
sued, which led some to deny the inspiration of
Paul himself, which he established by the mira¬
culous “ signs of an Apostle.”2
Some, again, have fallen into an extravagance
which prevails a good deal at the present day;
that of interpreting any part of Scripture they
please, allegorically, as being what they call a
“ Myth,” though stated by the Sacred Writers as
a simple fact. According to these persons, Scrip¬
ture is true indeed, but true only in the sense
which they chuse to put on it, and utterly untrue
1 See Paley’s Moral Philosophy.
2 The Religion of Mahomet may be reckoned as one of the corruptions of Christianity, and as owing, in some degree, its
origin, or at least some part of its wide diffusion, to a reaction against opposite corruptions. For the Mahometans, though
they account Mahomet a greater prophet than Jesus Christ, yet confess Jesus to be the Christ,—-to have been really sent
from God,—to have been superior to all who came before Him,—and to have established his claim by miracles. And the
chief part of the fables which they have mixed up with the Gospel-history, they borrowed from some of the earliest heretics.
This religion, in short, is evidently a corrupted offshoot of Christianity.
At the time when Mahomet arose, a great part of the Christian world had fallen into saint-worship, and the adoration of
pictures and images ; and had also corrupted the doctrine of the Trinity into something very nearly approaching to Tri¬
theism. Against these errors he vehemently protested, dwelling strongly on the Divine Unity, and on the duty of renoun¬
cing every kind of idolatry. But the principle of persecution—already admitted by most Christians,—he retained and
vigorously carried out. And along with the errors he rejected, he discarded also great part of the fundamentals of Chris¬
tianity, besides introducing much false doctrine of his own.
DISSERTATION THIRD.
535
in the sense in which it was understood for many
centuries, and in which the Writers knew it was
understood. To call this a Revelation is a mani¬
fest contradiction. But what such persons really
mean, or really believe, no one can decide. For,
by their own shewing, they have so low a moral
principle as to think it allowable for a man to
teach what he is conscious is false in the sense in
which he knows it will be understood; this being
the conduct they attribute to Writers whom they
regard as God’s messengers commissioned to in¬
struct mankind.1
Others, again, justly considering Holy Scrip¬
ture as the only sure foundation of Christian
doctrine, and perceiving that to set up the au¬
thority of Church-tradition as an infallible in¬
terpreter of Scripture, might make Scripture say
anything whatever, so as to render “ the Word
of God of none effect,—and perceiving also that
to shut out the People from the reading of Scrip¬
ture is a monstrous abuse,—were led into an op¬
posite extreme. They were for discarding all
catechisms, and other human statements of Chris¬
tian doctrine, and depriving every Church of the
office of teaching. They were for simply putting
the Bible into each person’s hands, and leaving
him to make out, by his own unassisted study of
it, whatever religion he could for himself. They
forgot that, of all the books of the New Testa¬
ment, there is not one that was written for the
purpose of making known the Christian Religion
to those who were quite strangers to it. On the
contrary, all those books were evidently written
for the use of such as were already Christians,
who had been carefully instructed [catechised]
(See Luke i. 4.), and examined in the Christian
Faith.
It is the office of a Church to teach, and of
Scripture to prove. We should study the Sacred
Books carefully, as alone possessing divine autho¬
rity in matters of faith. But we should study
them with the best helps we can obtain ; and
with care not to mistake the character of them,
and the purposes for which they were written.
In short, we should imitate the Bereans of old,
who did not refuse to hear the teachers that came
among them, but “ searched the Scriptures daily,
to see whether those things were so” which were
taught them, (Acts xvii. 11.)
Human teaching bears the same relation to
Scripture, that what is called “ paper currency”
does to the precious metals. Bank-notes and Bills
of Exchange, though of no intrinsic value, are
a very convenient circulating medium so long as
they really represent gold or silver, and are pay¬
able in coin on the demand of the holder. But
if these notes are made a legal tender, and are re¬
quired to be received in payment, by the decree
of the very government which issues them, and
on its bare word, without being convertible into
gold and silver, the result is, that those metals
soon disappear, and men are cheated of their
goods in exchange for worthless bits of paper.
Even so, as long as human teaching is really a
representative of Scripture, and Scripture proof
is always ready to be given, of whatever is taught,
then, and then only, we are secured against the
danger of having God’s Word superseded by
“ doctrines which are commandments of men.”
Then, again, some men’s horror of the doc¬
trine, that good works can claim merit in God’s
sight, and that pilgrimages to certain supposed
holy spots, and various kinds of self-torture, can
atone for sins, led them into the Antinomian error
of the ancient Gnostics. They taught the doc¬
trine of justification by faith, in such a sense as
to contradict the Apostle James, (ii. 17-26,) or at
least to leave their hearers utterly careless about
Christian holiness of life.
Other instances might be given of corrup¬
tions of Christian doctrine, arising in great mea¬
sure out of a reaction against opposite corrup¬
tions.
With respect to religious ordinances again, the
burdensome and often superstitious rites with
which Christian worship has been in some
Churches overlaid, have created such a reaction,
that some have even gone so far as to reject the
Sacraments distinctly appointed by Christ Him¬
self, and administered according to his direction
by his Apostles, (1 Cor. xi. 23-26.) And the per-
1 See Dr West’s “ Discourse on Reserve,” and Essay i. on the “ Kingdom of Christ.’
536
PRELIMINARY DISSERTATIONS.
version of the office of Christian Ministers by
those who have made them Sacerdotal Priests,
has driven some into a rejection of a regular
Christian Ministry altogether.
Others, again, not going quite so far, have yet
thought themselves bound to reject all institu¬
tions and ordinances that are not expressly en¬
joined in Scripture. There had been a manifest
abuse of Church-authority in introducing ordi¬
nances and customs that are contrary to Scrip¬
ture ; and again, in teaching doctrines that are
not contained in Scripture. And this produced a
reaction, which led men to confound these two
things together, and to deny the power which
manifestly belongs to a Church, of making bye¬
laws respecting matters intrinsically indifferent,
and in which Scripture gives no commands.
And some reformers seem to have been led by
their deep detestation of the corruptions they
have protested against, to endeavour to be as un¬
like as possible to the Church from which they
have revolted, even in matters indifferent: alter¬
ing for the sake of change. They ought to have
considered that t\iepresumption'is always against
a change ; that is, since change is not a good in
itself, none should be introduced unless it can be
shown to be needful, and to be a change for the
better.1
It is true, we may very rightly alter or reject
things, good or harmless in themselves, when
they are found to be very liable to abuse, or when
they cause unnecessary offence. Thus “ Heze-
kiah brake in pieces the brazen serpent which
Moses had made,” when he found that the Israel¬
ites burned incense before it. And the Apostle
Paul, though he decides that there was no harm
in eating meats offered to idols, yet forbids the
Corinthians to do so, when their eating it would
be misapprehended and,cause offence. So, also,
a statue or picture of Christ, or of any eminent
Christian, is not an evil in itself. But when it
is found that the vulgar pay adoration to images
or pictures, or that others apprehend them to be
doing so, then such images should be removed
from places of worship, as being a snare to weak
brethren.
This, however, is no exception to the above
rule, but an application of it. For in such a case,
there is a good reason for the change.
Lastly, the usurpation and extravagant claims
of a Church have driven some persons to set at
nought Church-government altogether, and to
overlook entirely the sanction which our Lord
Himself gave to Christian communities, and the
powers which He conferred on them. The erro¬
neous and over-strained notions of Church-unity
which have been above noticed as having contri¬
buted to maintain corruptions and to hinder re¬
forms, afterwards led to such a violent reaction, that
many thought nothing of the guilt of Schism, and
seemed even to forget that there was such a thing.
And this, in turn, has sometimes produced a con¬
trary reaction. The disgust and alarm caused
by those who revolt against all rules, and discard
the very notion of a Christian community, have
driven others to submit to the grossest abuses of
Church-authority, for the sake of good order and
peace. It is just so, that, in political affairs, also,
there is a constant reaction between tyranny
and anarchy; each in turn tending to produce
the other.
Many more instances might be adduced ; but
what have been noticed are sufficient as speci¬
mens, to shew how watchful reformers ought to
be against the tendency to reaction—against suf¬
fering incautious zeal to hurry them from one ex¬
treme into another.
We shall now proceed to treat somewhat more
fully of the questions relating to Church-
unity.
1 See Preface to the Book of Common Prayer.
DISSERTATION THIRD.
537
CHURCH ALLEGIANCE AND SEPARATIONS.
It has been pointed out that the correction of
abuses and corruptions in Religion has been, in
most instances, resisted and long delayed j partly
from an undue attention having been directed to
points of minor importance, which has drawn off
men’s thoughts from very serious errors; partly
from mistaken notions respecting Church-unity ;
and partly from a mistaken dread of innovation,
causing men to overlook what are in reality the
greatest innovations.
From these and other causes, various corrup¬
tions have often been allowed to go on unchecked
by timely remedies, and to increase, till a thorough
reformation was necessary; and indeed much
longer. And the longer a reformation is deferred,
the more difficult, and the more dangerous and
violent, it is likely to be.
In particular, a reformation very long delayed
is the more liable to those two classes of evils
mentioned above; [1.] the danger of retaining
some of the former wrong principles, so as to re¬
vive, under a new form, the faults which had been
corrected; and [II.] the danger of reactions, lead¬
ing men from one extreme into another.
[L] For, the longer any corruption has been al¬
lowed to prevail, the more it will have wrought
itself into men’s character, so as to have affected
their mind throughout, and become, as it were,
a part of themselves. And then, the same fault,
substantially, will be the more likely to reappear
in a different shape.
Thus, for instance, when the principle of per¬
secution, above adverted to, had been so very long
acted on, that men all over the world had been
familiarised to the putting down of heresies by
sword and fire, and the enforcement of the pro¬
fession of the true Faith bytheCivil Magistrate, as
an indispensable religious duty, the consequence
was, that reformers, even when exposed to perse¬
cution themselves, still clung to the faulty prin¬
ciple. They considered persecution, (as was be¬
fore observed,) as consisting in punishing those
who maintained the truth. And it was long be¬
fore they came to perceive,—what Scripture so
Diss. in.
very plainly points out,—the inconsistency with
Christ s Religion of all use of coercion in his
cause. And some remain blind to this, even down
to the present day.
And, again, when ignorance of the true cha¬
racter of Christianity, resulting from the non¬
translation of the Scriptures, had been very widely
spread and long continued, and then, persons who
had very little mental cultivation, and who had
been trained from childhood in most erroneous
religious notions, suddenly came to the perusal
of the Scriptures, (often without any assistance,)
it naturally happened that many of them fell into
gross mistakes as to the meaning of what they
read. In particular, they often mixed up together
confusedly the Law and the Gospel; and often
read detached passages, taken at random, with¬
out any reference to times, places, persons, and
occasions. And thus among many, ignorance of
the true character of Christianity continued, in a
great degree, to prevail, though in a new shape.
This has been often brought forward by the
opponents of the Reformation, as a proof of the
danger of putting the Scriptures into the hands
of the People. But if Christian Ministers had all
along done their duty in training the People to
an intelligent and profitable study of Scripture,
this evil would have been, for the most part pre¬
vented. Instead of this, they had kept them ig¬
norant and uneducated, generation after genera¬
tion. And mankind had been so long blindfolded
that they could not see clearly when the bandage
was removed.
[II.] And again, the longer and the more ob¬
stinately any needful reform has been resisted,
the more fierce in general will be the spirit in
which it is at length effected. Abuses which
have been maintained long after they have been
exposed and complained of, men are apt to cor¬
rect with an angry and indiscriminate violence,
which often leads them to rush into extremes, and
to reject what is true and right, along with what
is erroneous and faulty. Thus, one may some¬
times see long-continued tyranny succeeded by
3 v
538
PRELIMINARY DISSERTATIONS.
revolutionary anarchy; and a long reign of igno¬
rant superstition, even by avowed Atheism.
Many, also, of the evils which are apt to accom¬
pany any great religious reformation, have been
increased by the too great extent of a single
Church.
The Apostles appear to have founded a dis¬
tinct Church in each considerable city ; as at
Philippi, Thessalonica, and several other cities
in Macedonia, and elsewhere. Now, if some cor¬
ruption had found its way into these Churches,
and one of them—suppose Philippi—had re¬
formed itself, although it is likely that some de¬
gree of jealousy and disapprobation would have
at first arisen in the other Churches which were
as yet unreformed, and though the Philippians
might have been censured as having taken a rash
step, at least they could not have been denounced
as schismatical revolters. No one could have
complained that they had separated from a
Church of which they were subjects. They could
not have been viewed in the light of rebellious
children, throwing off the yoke of an authority
they had been subject to.
But when a multitude of Churches were united
into one vast Community, comprehending many
great Nations spread over extensive Regions, then
any reformation not embracing the whole oi this
great Church, necessarily implied revolt and
separation.
Any branch of that Church which resolved to
correct abuses that were obstinately retained by
the supreme central Authority, was compelled to
throw off submission to that Authority, and to
assert its independence. And then, those who
adhered to the Church which claimed to be the
Universal Church, naturally regarded the others
as not only erroneous, but Heretics and Schis¬
matics.
And such they undoubtedly would have been
had they separated on insufficient grounds. They
had done that which would have been sinful, if
it had not been justified by the corruptions in
essential points of Faith and Worship, which the
supreme central Authority had obstinately refused
to correct. This refusal transferred the sin of
causing the division, from the revolters. to those
who made the revolt necessary.
But of course a separation thus effected gave
rise to much more hostile feelings on both sides
than would have been likely to exist between
Churches that had been oi^ginally distinct, and
had always continued so; neither claiming any
control over the other. Such Churches might,
indeed, have been to a certain degree alienated
from each other by differences in Doctrine or
Discipline ; but there would not have been the
additional provocations of a revolt, and an un¬
friendly separation on the one side, and a claim
of supremacy on the other.
And, accordingly, it was on the very ground
of the Reformed being Heretics and Schismatics
that the secular power was called in to reduce
them by force to submission. Princes were not
called on to wage war against religious error,
merely as such ; but they were urged to reduce
to obedience those who had revolted against the
Church to which they were bound to be subject.
And thus religious wars, and fierce persecutions,
and mutual hatred were introduced, far beyond
what would have been likely to arise if the ori¬
ginal independence of numerous Churches had
always continued.
When several distinct Churches had been esta¬
blished in revolt—the members of them having
been compelled to secede from the Community
they had belonged to, on account of a disagree¬
ment as to the fundamentals of Christianity—the
result was, that the ideas of distinctness, and of
disagreement, often came to be, in some measure,
blended together in men’s minds. There was a
sort of presumption created, that any Churches
independent of each other may be expected to be
at variance. That mutual friendly feeling and
free inter-communion which prevailed in the
earliest ages—when an Ephesian Christian, for
instance, going to settle at Corinth, or at any
other place where there was a Christian Church,
and bringing proper testimonials, was at once
received as a member of that Church—were much
impaired, and sometimes forgotten.
And, moreover, when men had become fami¬
liarly accustomed to separation, from having been
forced into it, they were in danger of becoming
careless about it, and disposed to think lightly
of the sin of Schism.
Something similar takes place in many other
cases. For instance, those who have been placed
DISSERTATION THIRD.
539
in such circumstances as to make the shedding
of blood an unavoidable evil, are in danger of
gradually losing their original repugnance to it,
and becoming so far hardened, as to think little
of sacrificing human life, even without necessity.
It is the same in the matter now before us.
There is always a danger that necessary sepa¬
rations may lead to others not necessary, and
may have prepared men’s minds to make every
little difference, even on points of no vital im¬
portance, a ground for setting up new sects.
The colour of a Minister’s vestment,—the names
of the months,—and of the days of the week,—
the mode of conducting Church music,—the using
or not using of a ring in matrimony,—on these
and such like matters, differences of opinion have
been made a plea for separation.
Now, it is much less likely that this would have
occurred in Churches which had not broken off
from any other, but had been all along distinct
Communities. For though, in any such Church,
differences of opinion on minor points might
have arisen, it is likely that men would have
agreed to some compromise, rather than occasion
hostile divisions.
It is true, indeed, that in almost every ques¬
tion, however insignificant, there is a better and
a worse decision; and the decision of each man’s
own judgment will, of course, appear to himself
to be the better. But in matters not essential,
it is evidently a duty to yield, or to adopt a com¬
promise, rather than endanger Christian concord.
For if each person were to draw up what might
appear to himself the very best form of Church
Government, and the best possible mode of ex¬
pressing each Christian Doctrine, and the most
perfect Ritual for divine Worship, and should re¬
solve not to belong to any Church that did not
exactly adopt all these in every particular, it is
plain that there would be almost as many Sects
as families, and that no Christian community at
all could subsist for a single year.
But, as has been above said, when unfriendly
separations had been once begun, through a ne¬
cessity caused by the obstinate retaining of abuses,
causeless divisions often ensued from men’s hav¬
ing become familiarised to divisions, and almost
entirely regardless of Church-union.
And again, abhorrence of such divisions has
led some Christians to adopt the system of making
a State and a Church one Community, and as¬
signing to the Civil Magistrate the entire control
in spiritual matters, and the right of dictating to
the consciences of all the citizens. And thus under
the name of “ making the State religious” and
“ providing for the greatest good of its subjects,”
they make Christ’s a kingdom of this world.
With this fault, and with the endless divisions
which have contributed to cause it, Reformers
are often exultingly reproached by the advocates
of the system of having one great Church which
is to comprehend all Christians, and to dictate
to them their faith and practice. See, they say,
what are the consequences of once allowing any
separation from the Church on any grounds what¬
ever ! When you have once begun, you cannot
tell where to stop.
Now, in truth, that very Church from which
the Reformers revolted, Avas (as has been above
pointed out) the original cause of all these evils.
In the first place, by obstinately adhering to an
accumulated mass of gross corruptions, it made
a thorough reformation necessary. And secondly,
by having absorbed into one Community a mul¬
titude of distinct Churches, it made separation
a necessary part of reformation. And thus it
not only retarded needful reformations, and made
them more difficult, but also made them, when
they did come, much more hurtful, and more ex¬
posed to the dangers which are attendant on any
great reformation.
As for what are, and are not such essential
points as to AArarrant separation, it would of course
be unsuitable to our present purpose to enter on
the discussion of such a subject. But every one
should be warned, that in each question of the
kind that may arise, he is bound to inquire and
examine seriously, carefully, and dispassionately;
not as if it were merely a matter of taste, fancy,
or convenience. We are responsible to God for
the exercise of our best discretion in forming a
decision. And we are bound in duty to Him, to
take care neither to sacrifice the essentials of
Christianity for the sake of peace, nor again,
lightly and wantonly to cause divisions.
All separation, in short, and all resistance to
Church-authority, must be either a duty or a sin.
Which of the two it is, in each particular instance,
540
PRELIMINARY DISSERTATIONS.
each must decide according to the best of his judg¬
ment; which is, after all, fallible. And in no case
are we authorised to pronounce our neighbour
guilty of an unpardonable sin. But though Chris¬
tian charity requires us to make allowance for
those who appear to us blameable, it is no part
of charity to confound the distinctions of right
and wrong; nor indeed would there be any room
for the exercise of charity in judging of those
whom we do not consider to be acting wrongly .
On these and several other important questions
connected with religion, some persons are so dis¬
trustful of what they call “ private judgment,”—
that is, the judgment of the generality of men, and
of themselves,—that they resolve to renounce al¬
together the exercise of private judgment on all
religious questions, and to submit themselves in
every thing to the judgment of their Church.
They dwell much on the incompetency of most
men to decide rightly on difficult points; and
consider that there is a pious humility in deter¬
mining not to exercise their own judgment at all.
But they quite forget that, in the course they
adopt, they do decide on one most important and
difficult point. A man who resolves to place him¬
self under a certain guide to be implicitly follow¬
ed, and decides that such and such a Church is the
appointed infallible guide, does decide on his own
private judgment, that one most important point,
which includes in it all other decisions relative
to Religion. And if, by his own shewing, he is
unfit to judge at ail, he can have no ground for
confidence that he has decided it rightly. And
if, accordingly, he will not trust himself to judge
even on this point, but resolves to consult his
priest, or some other friends, and be led entirely
by their judgment thereupon, still he does, in thus
resolving, exercise his own judgment as to the
counsellors he so relies on.
There is no need, therefore, to dispute about
the right, or about the duty, of private judgment.
For there is plainly an unavoidable necessity of
private judgment, on anysubject wherein we take
any serious interest. The responsibility is one
which, however unfit we may deem ourselves to
bear it, we cannot possibly get rid of, in any mat¬
ter about which we really feel an anxious care. It
is in vain to discuss the questions whether we
may, or whether we ought, to exercise private
judgment, since we must do so, whether we will
or no.
That which often misleads men in this matter,
is that we can refrain from exercising private
judgment on this or that particular point, by
transferring our judgment to some other point.
For example—A sick man who is conscious of
his own want of knowledge of medicine, may re¬
frain from exercising any judgment as to the re¬
medies he should use, and may put himself
wholly in the hands of a physician ; that is, he
judges that a physician is needful, and that such
and such a practitioner is worthy of confidence.
Or, supposing he distrusts his own judgment on
this point also, then he consults some friend whom
judges to be trustworthy, as to what physician
he shall employ. In one way, or else in another,
he cannot but exercise private judgment. So,
also, if a man inherit a great fortune, and have
a strong sense of the great responsibility attend¬
ing it, and of his own unfitness to dispose of his
wealth, he may resolve to make it all over to
trustees, to distribute in charity at their discre¬
tion. He may have judged rightly in so doing;
but it is evident he does judge, and does exercise
an act of ownership once for all, in thus divest¬
ing himself of his property. And if he deem
himself incompetent even to the task of selecting
trustees, and relies on the judgment of some friend
as to what persons he shall appoint trustees, still
he is exercising his judgment in the selection of
that friend. The responsibility is one which he
cannot shake off, do what he will.
The man who in the course of God’s provi¬
dence comes into the possession of wealth, is by
that providence, entrusted with the stewardship
of that wealth, however ill-qualified he may seem,
to us, or to himself, for such a charge. And in¬
stead of murmuring or wondering at God’s dis¬
pensations, or trying in vain to shake off the re¬
sponsibility thus laid on him, he should set him¬
self to do the best he can towards the fulfilment
of the duty imposed on him.
And it is the same in all cases. We do and
must exercise our judgment, on one point or on
another, in all matters except those in which we
take no interest, and which do not occupy our
thoughts. In most of the causes, for instance,
which are tried in a court of justice, we do not
DISSERTATION THIRD.
541
trouble ourselves to exercise any judgment, if we
know or care nothing about either plaintiff or
defendant, and feel no interest in the decision.
Accordingly, if any one resolves that he will not
exercise any judgment on religious matters, and
really does consistently keep to that rule, not de¬
ceiving himself (as many do) in the way just above
noticed, by judging on one point instead of an¬
other, he will find that there is only one possible
way of complying with that rule—namely, by
withdrawing his attention as much as possible
from the whole subject, except as far as regards
outward forms and observances, and refraining
altogether from considering the questions, what
the Christian Religion is, and whether there is
any truth in it.
And there are not a few who really do, in this
way, abstain from exercising any judgment at all
in religious matters, and are content to do and
say just what they have been accustomed to, with¬
out any serious reflection on the subject. But
even so, they do not escape responsibility. For
we are responsible, not only for doing, but also
for leaving undone ; else, the servant who hid his
Lord’s talent in the earth would have escaped
condemnation.
Of course it is not meant that on any import¬
ant point a man ought to make up his mind, un¬
assisted, and without consulting those whom he
may consider to be intelligent, and well-informed,
and upright advisers. Only, let him not deceive
himself by imagining that he can forego all ex¬
ercise of his own judgment in any matter about
which he has a real and anxious care.
And on the other hand, we should guard against
the opposite mistake of supposing that whatever
is left to our owndiscretion is, therefore, left to our
caprice, and may be decided on at random. We
may have a right to do many things which we
should not be right in doing. For instance, when
any bill is brought into Parliament, each member
has an undoubted right to vote for it or against
it; but it would be absurd to say that he would
be equally right in doing either. It is in such
cases, and in such alone, that there is room for
the exercise of any such quality as good sense,
wisdom, discretion, &c. For, in matters quite
indifferent, there is clearly no exercise of judg¬
ment in deciding. Nor, again, is there any room
for it in matters that are already decided for us,
and in which we have no choice: as, for instance,
when a Judge has to declare what the law actu¬
ally is on such and such a point. But when a
Legislator is called on to decide what the law
ought to be, and, in short, in every case where
we have to decide, and where there may be a
better or a v/orse decision, it is then, and then
only, that there is room for the exercise of good
sense.
We should keep in mind, then, that as the ex¬
ercise of our own judgment (in matters in which
we feel a deep interest) is, on the one hand, un¬
avoidable, so it is, on the other hand, respon¬
sible. We are bound to use, to the best of our
power, such faculties and opportunities as God’s
providence may have bestowed onus, in judging
of any question pertaining to Religion; and
among others, in any question as to separation.
But though, as we have already said, much
blame attaches to those who hastily, and on slight
grounds, separate from their Church ; a Church,
on the other hand, is not exempted from a share
of blame, which narrows too much its terms of
communion. Some terms, of course, are indis¬
pensable; since persons differing as to the funda¬
mentals of Christian Doctrine and Worship cannot
possibly be members of the same Christian Com¬
munity. But care should be taken not to go be¬
yond what is necessary. If possible, none should
be excluded of those who can join in Christian
Worship together, and receive instruction toge¬
ther in the essential truths of the Gospel. To
multiply Articles of Faith and Ordinances, un¬
necessarily, manifestly tends to create divi¬
sions.
And it is not enough to say that these Articles
are, all, such as we are convinced are scriptural,
and that none of our Ordinances are contrary to
Scripture, and that the scruples of those who ob¬
ject to them are unfounded and frivolous. All
this may be true; and it may be true that those
are to blame who on such grounds separate from
the Church; yet this does not clear from blame
those who put a stumblingblock in the way of
weak brethren by insisting on points that are not
essential, and on which persons may differ who
are yet capable of worshipping together as Mem¬
bers of the same Christian Church. “ Him that
542
PRELIMINARY DISSERTATIONS.
is weak in the Faith, receive ye, but not to doubt¬
ful disputations.” (Rom. xiv. 1.)
It is to be observed, however, that when we
speak of points that are and that are not “ essen¬
tial,” we mean, in this place, essential as terms of
communion ; not, of salvation. For there are
some points of disagreement which would com¬
pletely prevent men from being Members of the
same Church, though hardly any, of either party,
would regard the other as under a fatal error.
For example, there are persons irreconcilably
opposed on the subject of Church-endowments.
Some of the advocates of what is called “ the
voluntary system” consider it as not only objec¬
tionable, but utterly unlawful, to attend what they
call a hired Ministry1—that is, one maintained by
endowments. And the other party, though not
holding it absolutely unlawful for a Minister to
be dependent on the voluntary contributions of
his People (since “ the labourer is worthy of his
hire,”) yet consider this so very undesirable, that
they would feel bound to support and promote
the system of endowments. Now these two
parties could hardly continue Members of the
same Church. And yet neither need regard the
other as having abandoned the fundamentals of
Christianity.
The same may be said of an irreconcilable dis¬
agreement as to the use of extemporary prayer,
and of stated/onns, in Public Worship. Some
consider the use of any form, even the Lord’s
Prayer, as not allowable. Others, again, believe
that a special promise is made to the “ common”
prayers of a Congregation who “ agree together
touching something they shall ask in Christ’s
nameand that, accordingly, they are bound to
pray together, (either audibly or mentally,) and
not merely to. listen to the prayers offered up by
another. And they hold it to be impossible, in
most cases, that a Congregation (at least, the w/ioZe
of it) can so constantly go along with all that is
said by an extemporary speaker, as to accompany
•—properly speaking—his prayers ; that is, so as
not only to understand and approve what he says,
but to make his prayers their own prayers also
at the moment. These prayers, accordingly, will
generally be, they conceive, rather of the charac¬
ter of exhortations addressed to the People by the
Minister, than of joint-prayers addressed by the
People to God.
Now persons strongly impressed with these
opposite notions could not be united in one
Church, though they may not regard each other
as fatally in error.
It has been above said, that a man is deeply
responsible for the sin of Schism, if he should,
without evident and strong necessity, separate
from his Church. But some have doubted what
Church it is that has this general claim to his al¬
legiance ; whether that which is established by
laiu; or that which his ancestors formerly be¬
longed to; or that in which he himself has been
brought up.
As for the first of these, the Religion esta¬
blished by law, has not, on that ground, any claim
on the conscience. A member, for example, of
the Church of England becomes a dissenter if he
settle in some part of the Empire where some
other form of religion is established. But if he
is conscientiously a member of his own original
Church, and sees no reason to consider it un-
scriptural, he has no right to forsake it on poli¬
tical grounds.
As for the Church to which one’s ancestors
may have belonged, no one should think himself
bound to investigate obscure and difficult ques¬
tions of history, and to judge of all the acts of
those who founded or reformed his Church, per¬
haps several centuries ago, in order to decide
whether he is permitted, or whether he is bound,
to continue in the Church in which he was
brought up. If those founders separated unrea¬
sonably, they indeed were chargeable with the
sin of Schism. But it would be to create a fresh
Schism, if he were to forsake the Church he was
brought up in, not from feeling any objection to
its Doctrines or Worship, but merely on the
ground that its original formation was not justi¬
fiable.
And a like principle is universally recognised
in all civil affairs. Else, indeed, the whole World
would be filled with perpetual rebellions and
1 More properly called wnhired; being supported, not like a labourer by the wages of his employer, but by endowments
similar to those of many Hospitals, Colleges, &c.
DISSERTATION THIRD.
543
civil wars. For example, every one knows that
Norway was formerly united, not to Sweden, but
to Denmark—that, in like manner, Normandy,
and other provinces of France, and also the North
American States, formerly belonged to England;
and that Ireland at one time consisted of several
independent Kingdoms. But if a Norman were
to hold that he owed no allegiance to the French
Government, or an American to that of the
United States, and so on, unless every such
separation and annexation could be proved ori¬
ginally justifiable, and if every man were to
think himself authorised on such grounds to raise
revolt, there would be hardly such a thing as a
peaceable Government on Earth.
Each man, therefore, owes allegiance, gene¬
rally, to the Church in which he has been brought
up, unless he find this incompatible with his
reverence for God’s Word, and his obedience to
the divine Will.
Independently, however, of any disagreement,
a separation may take place with the consent of
all parties, of one Branch of a Church from the
rest, merely from reasons of convenience, and
without any interruption of harmony and inter¬
communion, any more than among the several
distinct Churches originally founded by the
Apostles. For example, this took place with
the American Episcopalian Church, which for¬
merly was a portion of the Church of England.
When the American States became politically
independent, the inconvenience of having one
Church whose members were citizens of different
political Communities, was so plain to all parties,
that a friendly separation was agreed on. And
if this had been done long before, by mutual con¬
sent, merely on the ground of the inconvenient
distance between the two Countries, no one could
have had any right to find fault with the measure.
For, any union or separation that is made by mu¬
tual consent, is evidently a matter which the par¬
ties concerned have a full right to determine for
themselves.
But difficult questions may arise when both
parties do not thus agree ; those who desire to
form themselves into a distinct Church being
opposed by the rest. Suppose, for instance, that
on the occasion just alluded to, the English
Church had refused to consent to the independ¬
ence of the American, and had insisted on re¬
taining control over them. In any such case,
those desiring to secede should, in the first
place, satisfy themselves, on careful considera¬
tion, that the evils they seek to remedy are
not only real, but great, and likely to inter¬
fere with the objects for which Churches exist.
Next, they should respectfully, and in a spirit of
kindness, set forth their reasons, and listen
candidly to what may be urged on the opposite
side. And if they see no reason to alter their
opinion, they should still remonstrate earnestly
and perseveringly, before they take the extreme
step of seceding without the consent of their
brethren.
In these, however, and in all similar matters,
it is impossible to lay down rules such as will at
once apply to every case that may arise. There
must always be room for the exercise of sound
judgment and candour, in deciding on each par¬
ticular question.
There is one principle, however, which should
always be kept in mind, and which, obvious as
it is, men often lose sight of in practice; namely,
that a necessity imposed by external circum¬
stances, and for which we are not responsible,
will justify, and call for, such measures as would
be sinful if there were no such necessity. We
should be careful, therefore, not to commit either
the error of censuring men for doing what would,
in ordinary circumstances, be wrong; or the error
of supposing ourselves at liberty to do, at any
time and under any circumstances, whatever has,
in some particular case, been justifiably and
rightly done.
In the ordinary affairs of life, this principle is,
in general, well understood and acted on. For
example, for a number of men, citizens of any
State, to assemble, and by their own authority,
declare themselves a Senate, and proceed to elect
Magistrates, and enact Laws, and establish a Go¬
vernment, would justly be regarded as a most
heinous act of rebellion; and all their laws, (how¬
ever good in themselves,) would be evidently null
and void. But if a number of persons were to
find themselves wrecked on a desert island, or
the sole survivors of a pestilence, or in some other
way left to themselves, no one would contend
that they were bound thenceforward to live in a
544
PRELIMINARY DISSERTATIONS.
state of anarchy, because they had no legitimate
Rulers or Laws. They would be authorized, and
bound, to agree as well as they could, in establish¬
ing some sort of Government. And the Laws and
Magistrates thus appointed would have as good
a claim to obedience as those of any Country in
the World; because it is plainly necessary to hu¬
man welfare, and agreeable to the divine Will,
that men should live under a regular Government.
Yet this case would afford no precedent for any
persons who should take upon them to break up
an existing Community, and to revolt against
“ the Powers that be.”
So also, if the persons thus situated were to find
themselves without regularly ordained Clergy, or
without any except such as they were fully con¬
vinced had abandoned the genuine Doctrines of
the Gospel, it would be absurd to suppose it could
be the Will of their Heavenly Master, that they
should remain for ever destitute of a Christian
Ministry and Church-ordinances. They would
clearly be conforming to the spirit of his injunc¬
tions, in forming themselves into a Church, and
appointing various Orders of Ministers, selecting
the best qualified persons they could find, for each
office, and establishing Church-regulations ac¬
cording to the best of their judgment. And the
necessity under which they were placed, would
justify, and render valid, all their acts and ap¬
pointments ; supposing them always not to be in
themselves superstitious or unscriptural. But
such a case would afford no fair precedent for
persons differently circumstanced, who should
take upon themselves, wantonly and without ne¬
cessity, to ordain Ministers, and set up them¬
selves as a new Church.
So, also, there may be extreme cases of such
cruel and intolerable oppression as to justify sub¬
jects in revolting against an established Govern¬
ment. But extreme cases do not destroy the
authority of a general rule, though they may au¬
thorize an exceptional departure from it. And
it is undoubtedly true, as a general rule, that we
are in duty bound to submit to existing Govern¬
ments.
Again, if the loyal portion of a garrison were
to revolt from a general, who had turned traitor,
and was betraying the city into an enemy’s hands,
so far from being treasonable in thus revolting,
they would have been abettors of treason if they
had not. And yet the general rule is, that sol¬
diers are bound to obey their commander.
In like manner, submission to Church-autho¬
rity, and the preservation of Church-union, are
the rule; and resistance, or separation, the ex¬
ception. The burden of proof lies with those who
undertake to justify a departure from a rule. And
if they do thus justify themselves, their case af¬
fords no fair precedent for those who would in¬
troduce general discord and confusion.
It is to be observed, however, that when we
speak of the general claim to obedience, which the
Laws of any Community—civil or ecclesiastical—
have on its Members, this does not imply such a
blind veneration as should withhold us from seek¬
ing any needful amendment. Any one who scorns
the absurdity of attributing infallibility to human
Beings, would be himself guilty of a still greater
absurdity, if, while considering all men as fallible,
he should yet act as if they were in-fallible, by
insisting that all their institutions and regulations
should be like the Laws of theMedes and Persians,
which could never be changed; and that no one
should even inquire whether amendment in any
point be possible, and needful. All wanton and
hasty changes, indeed, should, in all subjects, be
avoided; the presumption being, as has been above
said, against every alteration. And a man’s vene¬
ration for any existing Constitution—whether in
Church or in State—may reasonably lead him to
deprecate any fundamental change. But the best
security against this,—in short, against revolu¬
tion,—is, the constant correction of abuses, and
the introduction of improvements as they are
needed. It is the neglect of timely repairs (as
was remarked above) that makes rebuilding ne¬
cessary.
And, moreover, the amendment of any Law
that is faulty, tends (beside the immediate bene¬
fit) to increase men’s confidence in those that are
left unchanged ; and in this way contributes to
the stability of the whole system. For it creates
a presumption that what is left unchanged, is so
left for some good and sufficient reasons, and not
from a mere blind determination against any
change, whether for the worse or for the better.
Some persons, however, there are, who are far
from thinking all existing laws (civil or eccle-
DISSERTATION THIRD.
545
siastical) faultless; and who, on that ground, hold
themselves at liberty to disobey or evade any that
they think objectionable. But if these very per¬
sons are called on to exert themselves to procure,
in a regular way, a remedy for the evil, they will
shrink from the trouble, or expense, or odium,
they might thus incur for the public good. There
are many, for example, who from their disappro¬
bation of the existing revenue laws, or game laws,
&c., will violate these without scruple, when they
can do so with impunity. But when urged to
exert themselves in perseveringly calling the at¬
tention of the Legislature to these laws, they
will plead that it is no concern of theirs, but only
of their Rulers.
And they act in the same way with respect to
Church-regulations; disregarding without scruple
any that they disapprove; but refusing to take
any pains for the regular correction of anything
they complain of.
But a truly conscientious and right-minded
man will pursue exactly the opposite course. As
long as a law exists, he will feel bound to obey
it, as far as he can with a safe conscience. But
if he consider it an unwise law, he will exert
himself to have it amended by competent au¬
thority ; or, if necessary, to have some competent
authority appointed for the purpose of rectifying
whatever may be amiss. These exertions may,
perhaps, cost him much more trouble and dis¬
comfort than he, individually, suffers from the
existing state of things. But he will not hesitate
to sacrifice his own immediate personal comfort
and ease, for the lasting benefit of his Country¬
men and fellow-Christians. For a true Christian
is most emphatically and pre-eminently public-
spirited. “ None op us,” says the Apostle Paul,
“ LIVETH UNTO HIMSELF.” (Rom. xiv. 7.) And
he who is the most sedulously occupied in working
out, on Gospel principles, his own salvation, will
always be found the most devotedly active in pro¬
moting the welfare of his brethren.
END OP DISSERTATION THIRD.
3 2
\
DISS. III.
DISSERTATION FOURTH:
EXHIBITING A GENERAL VIEW
OF THE
PROGRESS OF MATHEMATICAL AND PHYSICAL SCIENCE,
SINCE THE REVIVAL OF LETTERS IN EUROPE.
By JOHN PLAYFAIR,
PROFESSOR OF NATURAL PHILOSOPHY IN THE UNIVERSITY OF EDINBURGH,
FELLOW OF THE ROYAL SOCIETY OF LONDON,
AND SECRETARY OF THE ROYAL SOCIETY OF EDINBURGH.
DISSEKTATION FOURTH.
PART FIRST.
In conformity to the plan which has been
traced and executed with so much ability in the
First Dissertation, I am now to present the
reader with an historical sketch of the principal
discoveries made in Natural Philosophy, from
the revival of letters down to the present time.
In entering on this task, and on looking at the
instructive hut formidable model already set be¬
fore me, I should experience no small solicitude,
did I not trust that the subject of which I am to
speak, in order to he interesting, needs only to
he treated with clearness and precision. These
two requisites I will endeavour to keep steadily
in view.
In the order which I am to follow, I shall he
guided solely by a regard to the subserviency of
one science to the progress of another, and to
the consequent priority of the former in the or¬
der of regular study. For this reason, the his¬
tory of the pure Mathematics will be first consi¬
dered, as that science has been one of the two
principal instruments applied by the moderns to
the advancement of natural knowledge. The
other instrument is Experience ; and, therefore,
the principles of the inductive method, or of the
branch of Logic which teaches the application
of experiment and observation to the interpre¬
tation of nature, must he the second object of
inquiry; and in this article I shall give an ac¬
count of Bacon’s Philosophy, as applied to Phy¬
sical investigation. After these two sections,
which may in some measure be considered as
introductory, I am to treat of Natural Philo¬
sophy, under the divisions of Mechanics, Astro¬
nomy, and Optics. Under the general denomi¬
nation of Mechanics I include the theory of Mo¬
tion, as applied not only to solids, hut to fluids,
both incompressible and elastic. Optics I have
placed after Astronomy, because the discove¬
ries in Mechanics have much less affected the
progress of the former of these sciences than ot
the latter. To these will succeed a sixth divi¬
sion, containing the laws of the three unknown
substances, if, indeed, they may be called sub¬
stances,—Heat, Electricity, and Magnetism.
These, though very different, agree in some ge¬
neral characters. They permeate all substances,
though not with the same facility : and, if other
550
PRELIMINARY DISSERTATIONS.
bodies had been formed in the same manner
with them, the idea of impenetrability would
never have been suggested to the mind. They
seem to receive motion, without taking any away
from the body which communicates it; so that
they can hardly be considered as inert. Two of
them, Heat and Electricity, are perceived by the
sense of touch; but the impression which they
make does not convey an idea of resistance.
The third is not perceived by touch; and, there¬
fore, all the three might be denominated impal¬
pable substances. If they have any gravity, it
cannot be appreciated; and, for these reasons,
had it not too paradoxical an appearance, we
might class them together as material, but incor¬
poreal substances. We know, indeed, nothing
of them but as powers, transferable from one
body to another; and it is in consequence of this
last circumstance alone that they are entitled to
the name of substances.
Though the general design of this historical
sketch extends from the revival of letters to
the beginning of the nineteenth century, I
shall, in the present Part, confine myself en¬
tirely, as has been done in the first Disser¬
tation, to the period preceding the end of the
seventeenth century, or, more precisely, to
that preceding the invention of the fluxionary
calculus, and the discovery of the principle of
gravitation;—one of the most remarkable epo-
chas, without doubt, in the history of human
knowledge.
SECTION I.
MATHEMATICS.
1. GEOMETRY.
The great inheritance of mathematical know¬
ledge which the ancients bequeathed to poste¬
rity could not, on the revival of learning, be im¬
mediately taken possession of, nor could even its
existence be discovered, but by degrees. Though
the study of the Mathematics had never been
entirely abandoned, it had been reduced to mat¬
ters of very simple and easy comprehension,
such as were merely subservient to practice.
There had been men who could compute the
area of a triangle, draw a meridian line, or even
construct a sun-dial, in the worst of times; but
between such skill, and the capacity to under¬
stand or the taste to relish the demonstrations
of Euclid, Apollonius, or Archimedes, there was
a great interval, and many difficulties were to
be overcome, for which much time, and much
subsidiary knowledge, were necessary. The repo¬
sitories of the ancient treasures were to be open¬
ed, and made accessible; the knowledge of the
languages was to be acquired; the manuscripts
were to be deciphered; and the skill of the
grammarian and the critic were to precede, in
a certain degree, that of the geometrician or the
astronomer. The obligations which we have to
those who undertook this laborious and irksome
task, and who rescued the ancient books from
the prisons to which ignorance and barbarism
had condemned them, and from the final de¬
struction by which they must soon have been
overtaken, are such as we can never sufficiently
acknowledge; and indeed we shall never know
even the names of many of the benefactors to
whom our thanks are due. In the midst of the
wars, the confusion, and bloodshed, which over¬
whelmed Europe during the middle ages, the
religious houses and monasteries afforded to the
remains of ancient learning an asylum, which a
salutary prejudice forced even the most lawless
to respect; and the authors who have given the
best account of the revival of letters, agree that
it is in a great measure to those establishments
DISSERTATION' FOURTH.
551
that we owe the safety of the books which have
kept alive the scientific and literary attainments
of Greece and Rome.
The study of the remains of antiquity gradual¬
ly produced men of taste and intelligence, who
were able to correct the faults of the manu¬
scripts they copied, and to explain the difficul¬
ties of the authors they translated. Such were
Purbach, Regiomontanus, Commandine, Mau-
rolycus, and many others. By their means, the
writings of Euclid, Archimedes, Apollonius,
Ptolemy, and Pappus, became known and acces¬
sible to men of science. Arabia contributed its
share towards this great renovation, and from the
language of that country was derived the know¬
ledge of many Greek books, of the originals of
which, some were not found till long afterwards,
and others have never yet been discovered.
In nothing, perhaps, is the inventive and ele¬
gant genius of the Greeks better exemplified
than in their geometry. The elementary truths
of that science were connected by Euclid into
one great chain, beginning from the axioms,
and extending to the properties of the five regu¬
lar solids; the whole digested into such admir¬
able order, and explained with such clearness
and precision, that no similar wmrk of superior
excellence has appeared, even in the present ad¬
vanced state of mathematical science.
Archimedes had assailed the more difficult
problems of geometry, and, by means of the
method of Exhaustions, had demonstrated many
curious and important theorems with regard to
the lengths and areas of curves and the con¬
tents of solids. The same great geometer had
given a beginning to physico-mathematical sci¬
ence, by investigating several propositions, and
resolving several problems in Mechanics and
Hydrostatics.
Apollonius had treated of the Conic Sections,
—the curves which, after the circle, are the
most simple and important in geometry; and,
by his elaborate and profound researches, had
laid the foundation of discoveries which were
to illustrate very distant ages.
Another great invention, the Geometrical
Analysis, ascribed very generally to the Plato¬
nic school, but most successfully cultivated by
the geometer just named, is one of the most in¬
genious and beautiful contrivances in the Mathe¬
matics. It is a method of discovering truth by
reasoning concerning things unknown, or pro¬
positions merely supposed, as if the one were
given, or the other were really true. A quan¬
tity that is unknown, is only to be found from
the relations which it bears to quantities that
are known. By reasoning on these relations,
we come at last to some one so simple, that the
thing sought is thereby determined. By this
analytical process, therefore, the thing required
is discovered, and we are at the same time put
in possession of an instrument by which new
truths may be found out, and which, when skill
in using it has been acquired by practice, may
be applied to an unlimited extent.
A similar process enables us to discover the
demonstrations of propositions, supposed to be
true, or, if not true, to discover that they are
false.
This method, to the consideration of which
we shall again have an opportunity of return¬
ing, was perhaps the most valuable part of the
ancient Mathematics, inasmuch as a method of
discovering truth is more valuable than the
truths it has already discovered. Unfortunate¬
ly, however, the fragments containing this pre¬
cious remnant had suffered more from the in¬
juries of time than almost any other.
In the fifteenth century, Regiomontanus, al¬
ready mentioned, is the mathematician who
holds the highest rank. To him we owe many
translations and commentaries, together with
several original and valuable works of his own.
Trigonometry, which had never been known to
the Greeks as a separate science, and which
took that form in Arabia, advanced, in the
hands of Regiomontanus, to a great degree of
perfection, and approached very near to the
condition which it has attained at the present
day. He also introduced the use of decimal
fractions into arithmetic, and thereby gave to
that scale its full extent, and to numerical com¬
putation the utmost degree of simplicity and
enlargement which it seems capable of attain¬
ing. (oj
This eminent man was cut off in the prime
of life; and his untimely death, says Mr Smith,
amidst innumerable projects for the advance-
552
PRELIMINARY DISSERTATIONS.
ment of science, is even at this day a matter of
regret.1 He was buried in the Pantheon at
Rome; and the honours paid to him at his
death prove that science had now become a
distinction which the great were disposed to
recognise.
Werner, who lived in the end of this century,
is the first among the moderns who appears to
have been acquainted with the geometrical ana¬
lysis. His writings are very rare, and I have
never had an opportunity of examining them.
What I here assert is on the authority of Mon-
tucla, whose judgment in this matter may he
safely relied on, as he has shown, by many in¬
stances, that he was well acquainted with the
nature of the analysis referred to. It is not a
little remarkable that Werner should have under¬
stood this subject, when we find many eminent
mathematicians, long after his time, entiicly
unacquainted with it, and continually express¬
ing their astonishment how the ancient geo¬
meters found out those simple and elegant con¬
structions and demonstrations, of which they
have given so many examples. In the days of
Werner there was no ancient hook known, ex¬
cept the Data of Euclid, from which any infor¬
mation concerning the geometrical analysis could
he collected; and it is highly to his credit, that,
without any other help, he should have come to
the knowledge of a method not a little recondite
in its principles, and ampng the finest inventions
either of ancient or of modern science. Werner
resolved, by means of it, Archimedes’s problem
of cutting a sphere into two segments, having a
given ratio to one another. He proposed also to
translate, from the Arabic, the work of Apollo¬
nius, entitled Sectio Ratio?iis, rightly judging it
to he an elementary work in that analysis, and
to come next after the Data of Euclid.2
Benedetto, an Italian mathematician, appears
also to have been very early acquainted with the
principles of the same ingenious method, as he
published a hook on the geometrical analysis at
Turin in 1585.
Maurolycusof Messina flourished in the middle
of the sixteenth century, and is justly regarded
as the first geometer of that age. Beside fur¬
nishing many valuable translations and com¬
mentaries, he wrote a treatise on the Conic Sec¬
tions, which is highly esteemed. He endeavour¬
ed also to restore the fifth hook of the Conics of
Apollonius, in which that geometer treated of
the maxima and minima of the conic sections.
His writings all indicate a man of clear concep¬
tions, and of a strong understanding; though
he is taxed with having dealt in astrological pre¬
diction.
In the early part of the seventeenth century,
Cavalieri was particularly distinguished, and
made an advance in the higher geometry, which
occupies the middle place between the discoveries
of Archimedes and those of Newton.
For the purpose of determining the lengths
and areas of curves, and the contents of solids
contained within curve superficies, the ancients
had invented a method, to which the name of
Exhaustions has been given ; and in nothing,
perhaps, have they more displayed their powers
of mathematical invention.
Whenever it is required to measure the space
bounded by curve lines, the length of a curve,
or the solid contained within a curve superficies,
the investigation does not fall within the range
of elementary geometry. Rectilineal figures are
compared, on the principle of superposition, by
help of the notion of equality which is derived
from the coincidence of magnitudes both similar
and equal. Two rectangles of equal bases and
equal altitudes are held to be equal, because they
can perfectly coincide. A rectangle and an
oblique angled parallelogram, having equal bases
and altitudes, are shown to he equal, because
the same triangle, taken from the rectangle on
one side, and added to it on the other, converts
it into the parallelogram; and thus two magni¬
tudes which are not similar, are shown to have
equal areas. In like manner, if a triangle and
a parallelogram have the same base and altitude,
the triangle is shown to be half the parallelo¬
gram ; because, if to the triangle there be added
another, similar and equal to itself, hut in the
reverse position, the two together will compose
1 History of Astronomy, p. 90. Regiomontanus was born in 1436, and died in 1476.
* See Montucla, Hisloire des Mathtmaiiqucs, vol. I. p. 581.
DISSERTATION FOURTH.
553
a parallelogram, having the same base and alti¬
tude with the given triangle. The same is true
of the comparison of all other rectilineal figures;
and if the reasoning he carefully analyzed, it
will always he found to he reducible to the pri¬
mitive and original idea of equality, derived
from things that coincide or occupy the same
space; that is to say, the areas which are proved
equal are always such as, by the addition or
suhtractioR of equal and similar parts, may be
rendered capable of coinciding with one another.
This principle, which is quite general with re¬
spect to rectilineal figures, must fail, when we
would compare cumulineal and rectilineal spaces
with one another, and make the latter serve as
measures of the former; because no addition or
subtraction of rectilineal figures can ever pro¬
duce a figure which is curvilineal. It is possible,
indeed, to combine curvilineal figures, so as to
produce one that is rectilineal; but this principle
is of very limited extent; it led to the quadra¬
ture of the lunula of Hippocrates, but has hard¬
ly furnished any other result which can be con¬
sidered as valuable in science.
In the difficulty to which geometers were thus
reduced, it might occur, that by inscribing a
rectilineal figure within a curve, and circum¬
scribing another round it, two limits could be
obtained, one greater and the other less than the
area required. It was also evident, that by in¬
creasing the number, and diminishing, the sides
of those figures, the two limits might be brought
continually nearer to one another, and of course
noarer to the curvilineal area, which was always
intermediate between them. In prosecuting this
sort of approximation, a result was at length
found out, which must have occasioned no less
surprise than delight to the mathematician who
first encountered it. The result I mean is, that,
when the series of inscribed figures was con¬
tinually increased, by multiplying the number
of the sides, and diminishing their size, there
was an assignable rectilineal area, to which they
continually approached, so as to come nearer it
than any difference that could be supposed. The
same limit would also be observed to belong to
the circumscribed figures, and therefore it could
be no other than the curvilineal area required.
It appears to have been to Archimedes that a
DISS. IV^ PART I.
truth of this sort first occurred, when he found
that two-thirds of the rectangle, under the or¬
dinate and abscissa of a parabola, was a limit
always greater than the inscribed rectilineal
figure, and less than the circumscribed. In
some other curves, a similar conclusion was
found; and Archimedes contrived to show that
it was impossible to suppose that the area of
the curve could differ from the said limit, with¬
out admitting that the circumscribed figure
might become less, or the inscribed figure great¬
er than the curve itself. The method of Ex¬
haustions was the name given to the indirect
demonstrations thus formed. Though few things
more ingenious than this method have been de¬
vised, and though nothing could be more con¬
clusive than the demonstrations resulting from
it, yet it laboured under two very considerable
defects. In the first place, the process by which
the demonstration was obtained was long and
difficult; and, in the second place, it was indi¬
rect, giving no insight into the principle on
which the investigation was founded. Of con¬
sequence, it did not enable one to find out simi¬
lar demonstrations, nor increase one’s power of
making more discoveries of the same kind. It
was a demonstration purely synthetical, and re¬
quired, as all indirect reasoning must do, that
the conclusion should be known before the rea¬
soning is begun. A more compendious, and a
more analytical method, was therefore much to
be wished for, and was an improvement which,
at a moment when the field of mathematical
science was enlarging so fast, seemed particu¬
larly to be required.
Cavalleri, born at Milan in the year 1598, is
the person by whom this great improvement
was made. The principle on which he proceed¬
ed was, that areas may be considered as made
up of an infinite number of parallel lines; so¬
lids of an infinite number of parallel planes ;
and even lines themselves, whether curve or
straight, of an infinite number of points. The
cubature of a solid being thus reduced to the
summation of a series of planes, and the quad¬
rature of a curve to the summation of a series
of ordinates, each of the investigations was re¬
duced to something more simple. It added to
this simplicity not a little, that the sums of se-
4 A
554
PRELIMINARY DISSERTATIONS.
ries are often more easily found when the num¬
ber of terms is infinitely great, than when it is
finite, and actually assigned.
It appears that a tract on Stereometry, writ¬
ten by Kepler, whose name will hereafter he
often mentioned, first led Cavalleri to take
this view of geometrical magnitudes. In that
tract, which was published in 1615, the mea¬
surement of many solids was proposed, which
had not before fallen under the consideration of
mathematicians. Such, for example, was that
of the solids generated by the revolution of a
curve, not about its axis, but about any line
whatsoever. Solids of that kind, on account of
their affinity with the figure of casks, and ves¬
sels actually employed for containing liquids,
appeared to Kepler to offer both curious and
useful subjects of investigation. There were no
less than eighty-four such solids, which he pro¬
posed for the consideration of mathematicians.
He was, however, himself unequal to the task
of resolving any but a small number of the
simplest of these problems. In these solutions,
he was bold enough to introduce into geometry,
for the first time, the idea of infinitely great
and infinitely small quantities; and by this ap¬
parent departure from the rigour of the science,
he rendered it in fact a most essential service.
Kepler conceived a circle to he composed of an
infinite number of triangles, having their com¬
mon vertex in the centre of the circle, and their
infinitely small bases in the circumference. It
is to be remarked, that Galileo had also intro¬
duced the notion of infinitely small quantities,
in his first dialogue- De Mechanica, where he
treats of a cylinder cut out of a hemisphere;
and he has done the same in treating of the ac¬
celeration of falling bodies. Cavalleri was the
friend and disciple of Galileo, hut much more
profound in the Mathematics. In his hands the
idea took a more regular and systematic form,
and was explained in his work on Indivisibles,
published in 1635.
The rule for summing an infinite series of
terms in arithmetical progression had been long
known, and the application of it to find the area
of a triangle, according to the method of indi¬
visibles, was a matter of no difficulty. The
next step was, supposing a series of lines in
arithmetical progression, and squares to be de¬
scribed on each of them, to find what ratio the
sum of all these squares bears to the greatest
square, taken as often as there are terms in the
progression. Cavalleri showed, that when the
number of terms is infinitely great, the first of
these sums is just one-third of the second. This
evidently led to the cubature of many solids.
Proceeding one step farther, be sought for
the sum of the cubes of the same lines, and
found it to be one-fourth of the greatest, taken
as often as there are terms; and, continuing
this investigation, he was able to assign the sum
of the ^th powers of a series in arithmetical
progression, supposing always the difference of
the terms to be infinitely small, and their num¬
ber to be infinitely great. The number of cu¬
rious results obtained from these investigations
may be easily conceived. It gave, over geome¬
trical problems of the higher class, the same
power which the integral calculus, or the in¬
verse method of fluxions does, in the case when
the exponent of the variable quantity is an in¬
teger. The method of indivisibles, however,
was not without difficulties, and could not but
be liable to objection, with those accustomed to
the rigorous exactness of the ancient geometry.
In strictness, lines, however multiplied, can
never make an area, or any thing but a line;
nor can areas, however they may be added to¬
gether, compose a solid, or any thing but an area.
This is certainly true, and yet the conclusions
of Cavalleri, deduced on a contrary supposition,
are true also. This happened, because, though
the suppositions that a certain series of lines, in¬
finite in number, and contiguous to one another,
may compose a certain area, and that another
series may compose another area, are neither of
them true; yet is it strictly true, that the one
of these areas must have to the other the same
ratio which the sum of the one series of lines
has to the sum of the other series. Thus, it is
the ratios of the areas, and not the areas abso¬
lutely considered, which are determined by the
reasonings of Cavalleri; and that this determi¬
nation of their ratios is quite accurate, can very
readily be demonstrated by the method of ex¬
haustions.
The method of indivisibles, from the great
DISSERTATION FOURTH.
555
facility with which it could be managed, fur¬
nished a most ready method of ascertaining
the ratios of areas and solids to one another,
and, therefore, scarcely seems to deserve the
epithet which Newton himself bestows upon it,
of involving in its conceptions something harsh,
[durum) and not easy to be admitted. It was
the doctrine of infinitely small quantities carried
to the extreme, and gave at once the result of
an infinite, series of successive approximations.
Nothing, perhaps, more ingenious, and certainly
nothing more happy, ever was contrived, than
to arrive at the conclusion of all these approxi¬
mations, without going through the approxima¬
tions themselves. This is the purpose served
hy introducing into Mathematics the considera¬
tion of quantities infinitely small in size, and
infinitely great in number; ideas which, how¬
ever inaccurate they may seem, yet, when care¬
fully and analogically reasoned upon, have never
led into error.
Geometry owes to Cavulleri, not only the ge¬
neral method j ust described, but many particular
theorems, which that method was the instru¬
ment of discovering. Among these is the very
remarkable proposition, that as four right angles,
to the excess of the three angles of any spherical
triangle, above two right angles, so is the superficies
of the hemisphere to the area of the triangle. At
that time, however, science was advancing so
fast, and the human mind was everywhere ex¬
panding itself with so much energy, that the
same discovery was likely to be made by more
individuals than one at the same time. It was
not known in Italy in 1632, when this deter¬
mination of the area of a spherical triangle was
given by Cavalleri, that it had been published
three years before by Albert Girard, a mathe¬
matician of the Low Countries, of whose in¬
ventive powers we shall soon have more occa¬
sion to speak.
The Cycloid afforded a number of problems,
well calculated to exercise the proficients in the
geometry of indivisibles, or of infinites. It is
the curve described by a point in the circumfe¬
rence of a circle, while the circle itself rolls in
a straight line along a plane. It is not quite
certain when this curve, so remarkable for its
curious properties, and for the place which it
occupies in the history of geometry, first drew
the attention of mathematicians. In the year
1639, Galileo informed his friend Torricelli,
that, forty years before that time, he had thought
of this curve, on account of its shape, and the
graceful form it would give to arches in archi¬
tecture. The same philosopher had endeavoured
to find the area of the cycloid; but though he
was one of those who first introduced the con¬
sideration of infinites into geometry, he was not
expert enough in the use of that doctrine, to be
able to resolve this problem. It is still more
extraordinary, that the same problem proved
too difficult for Cavalleri, though he certainly
was in complete possession of the principles by
which it was to be resolved. It is, however, not
easy to determine whether it be to Torricelli,
the scholar of Cavalleri, and his successor in
genius and talents, or to Roberval, a French
mathematician of the same period, and a man
also of great originality and invention, that sci¬
ence is indebted for the first quadrature of the
cycloid, or the proof that its area is three times
that of its generating circle. Both these mathe¬
maticians laid claim to it. The French and
Italians each took the part of their own coun¬
tryman; and in their zeal have so perplexed the
question, that it is hard to say on which side
the truth is to be found. Torricelli, however,
was a man of a mild, amiable, and candid dis¬
position ; Roberval of a temper irritable, vio¬
lent, and envious; so that, in as far as the testi¬
mony of the individuals themselves is concerned,
there is no doubt which ought to preponderate.
They had both the skill and talent which fitted
them for this, or even for more difficult re¬
searches.
The other properties of this curve, those that
respect its tangents, its length, its curvature,
&c. exercised the ingenuity, not only of the
geometers just mentioned, but of Wren, Wallis,
Huygens, and, even after the invention of the
integral calculus, of Newton, Leibnitz, and Ber¬
noulli.
Roberval also improved the method of quad¬
ratures invented by Cavalleri, and extended his
solutions to the case, when the powers of the
terms in the arithmetical progression of which
the sum was to be found were fractional; and
556
PRELIMINARY DISSERTATIONS.
Wallis added the case when they were negative.
Fermat, who, in his inventive resources, as well
as in the correctness of his mathematical taste,1
yielded to none of his contemporaries, applied
the consideration of infinitely small quantities
to determine the wuxima and minimci of the or¬
dinates of curves, as also their tangents. Bar-
row, somewhat later, did the same in England.
Afterwards the geometry of infinites fell into
the hands of Leibnitz and Newton, and acquired
that new character which marks so distinguished
an era in the mathematical sciences.
2. ALGEBRA.
It was not from Greece alone that the light
proceeded which dispelled the darkness of the
middle ages; for, with the first dawn of that
light, a mathematical science, of a name and
character unknown to the geometers of antiqui¬
ty, was received in Europe from Arabia. As
early as the beginning of the thirteenth century,
Leonardo, a merchant of Pisa, having made fre¬
quent visits to the East, in the course of com¬
mercial adventure, returned to Italy enriched
by the traffic, and instructed by the science of
those countries. He brought with him the know¬
ledge of Algebra; and a late writer quotes a
manuscript of his, hearing the date of 1202, and
another that of 1228.2 The importation of al¬
gebra into Europe is thus carried hack nearly
200 year's farther than has generally been sup¬
posed; for Leonardo has been represented as
flourishing in the end of the fourteenth century,
instead of the very beginning of the thirteenth.
It appears, by an extract from his manuscript,
published by the above author, that his know¬
ledge of algebra extended as far as quadratic
equations. The language was very imperfect,
corresponding to the infancy of the science; the
quantities and the operations being expressed in
words, with the help only of a few abbreviations.
The rule for resolving quadratics by completing
the square, is demonstrated geometrically.
Though algebra was brought into Europe
from Arabia, it is by no means certain that this
last is its native country. There is, indeed,
reason to think that its invention must he
sought for much farther to the East, and pro¬
bably not nearer than Indostan. We are as¬
sured by the Arabian writers, that Mahomet
Ben Musa of Chorasan, distinguished for his
mathematical knowledge, travelled, about the
year 959, into India, for the purpose of receiving
further instruction in the science which he cul¬
tivated. It is likewise certain, that some hooks,
which have lately been brought from India into
this country, treat of algebra in a manner that
has every appearance of originality, or at least
of being derived from no source with which we
are at all acquainted.
Before the time of Leonardo of Pisa, an im¬
portant acquisition, also from the East, had
greatly improved the science of arithmetic.
This was the use of the Arabic notation, and
the contrivance of making the same character
change its signification, according to a fixed
rule, when it changed its position, being increased
tenfold for every place that it advanced towards
the left. The knowledge of this simple but re¬
fined artifice was learned from the Moors by
Gerhert, a monk of the Low Countries, in the
tenth century, and by him made known in Eu¬
rope. Gerhert was afterwards Pope, by the
name of Silvester the Second, hut from that
high dignity derived much less glory than from
having instructed his countrymen in the deci¬
mal notation.
The writings of Leonardo, above mentioned,
have remained in manuscript; and the first
printed hook in algebra is that of Lucas de
Burgo, a Franciscan, who, towards the end of
the fifteenth century, travelled, like Leonardo,
into the East, and was there instructed in the
principles of algebra. The characters employed
in his work, as in those of Leonardo, are mere
abbreviations of words. The letters p and m
1 He also was very skilful in the geometric analysis, and seems to have more thoroughly imbibed the spirit of that in¬
genious invention than any of the modems before Halley.
* M. Cossali of Pisa, in a tract on the Origin of Algebra, 1797-
DISSERTATION FOURTH.
557
denote plus and minus; and the rule is laid
down, that, in multiplication, plus into minus
gives minus, but minus into minus gives plus.
Thus the first appearance of algebra is merely
that of a system of short-hand writing, or an
abbreviation of common language, applied to
the solution of arithmetical problems. It was
a contrivance merely to save trouble; and yet
to this contrivance we are indebted tor the
most philosophical and refined art which men
have yet employed for the expression of their
thoughts. This scientific language, therefore,
like those in common use, has grown up slowly,
from a very weak and imperfect state, till it
has reached the condition in which it is now
found.
Though in all this the moderns received none
of their information from the Greeks, yet a work
in the Greek language, treating of arithmetical
questions, in a manner that may be accounted
algebraic, was discovered in the course of the
next century, and given to the world, in a Latin
translation, by Xylander, in 1575. This is the
work of Diophantus of Alexandria, who had
composed thirteen books of Arithmetical Ques¬
tions, and is supposed to have flourished about
150 years after the Christian era. The ques¬
tions he resolves are often of considerable diffi¬
culty ; and a great deal of address is displayed
in stating them, so as to bring out equations of
such a form as to involve only one power of the
unknown quantity. The expression is that of
common language, abbreviated and assisted by
a few symbols. The investigations do not ex¬
tend beyond quadratic equations; they are,
however, extremely ingenious, and prove the
author to have been a man of talent, though the
instrument he worked with was weak and im-
pei’fect.
The name of Cardan is famous in the history
of algebra. He was horn at Milan in 1501, and
was a man in whose character good and ill,
strength and weakness, were mixed up in sin¬
gular profusion. With great talents and indus¬
try, he was capricious, insincere, and vain-glo¬
rious to excess. Though a man of real science,
he professed divination, and was such a believer
in the influence of the stars, that he died to ac¬
complish an astrological nredmtiom He remains,
accordingly, a melancholy proof, that there is no
folly or weakness too great to he united to high
intellectual attainments.
Before his time very little advance had been
made in the solution of any equations higher
than the second degree; except that, as we are
told, about the year 1508, Scipio Ferrei, Profes¬
sor of Mathematics at Bologna, had found out a
rule for resolving one of the cases of cubic equa¬
tions, which, however, he concealed, or commu¬
nicated only to a few of his scholars. One of
these, Florido, on the strength of the secret he
possessed, agreeably to a practice then common
among mathematicians, challenged Tartalea of
Brescia, to contend with him in the solution of
algebraic problems. Florido had at first the ad¬
vantage ; but Tartalea, being a man of ingenuity,
soon discovered his rule, and also another much
more general, in consequence of which he came
off at last victorious. By the report of this vic¬
tory, the curiosity of Cardan was strongly ex¬
cited ; for, though he was himself much versed
in the Mathematics, he had not been able to dis¬
cover a method of resolving equations higher
than the second degree. By the most earnest
and importunate solicitation, he wrung from
Tartalea the secret of his rules, hut not till he
had hound himself, by promises and oaths, never
to divulge them. Tartalea did not communicate
the demonstrations, which, however, Cardan
soon found out, and extended, in a very inge¬
nious and systematic manner, to all cubic equa¬
tions whatsoever’. Thus possessed of an import¬
ant discovery, which was at least in a great part
his orvn, he soon forgot his promises to Tartalea,
and published the whole in 1545, not concealing,
however, what he owed to the latter. Though
a proceeding so directly contrary to an express
stipulation cannot be defended, one does not
much regret the disappointment of any man
who would make a mystery of knowledge, or
keep his discoveries a secret, for purposes mere¬
ly selfish.
Thus was first published the rule which still
hears the name of Cardan, and which, at this
day, marks a point in the progress of algebraic
investigation, which all the efforts of succeeding
analysts have hardly been able to go beyond.
As to the general doctrine of equations, it ap-
558
PRELIMINARY DISSERTATIONS.
pears that Cardan was acquainted both with
the negative and positive roots, the former of
which he called hy the name of false roots. He
also knew that the number of positive, or* as he
called them, true roots, is equal to the number
of the changes of the signs of the terms; and
that the coefficient of the second term is the dif¬
ference between the sum of the true and the
false roots. He also had perceived the difficulty
of that case of cubic equations, which cannot he
reduced to his own rule. He was not able to
overcome the difficulty, hut showed how, in all
cases, an approximation to the roots might he
obtained.
There is the more merit in these discoveries,
that the language of algebra still remained very
imperfect, and consisted merely of abbreviations
of words. Mathematicians were then in the prac¬
tice of putting their rules into verse. Cardan
has given his a poetical dress, in which, as may
be supposed, they are very awkward and ob¬
scure ; for whatever assistance in this way is
given to the memory, must he entirely at the
expense of the understanding. It is, at the same
time, a proof that the language of algebra was
very imperfect. Nobody now thinks of trans¬
lating an algebraic formula into verse; because,
if one has acquired any familiarity with the lan¬
guage of the science, the formula will be more
easily remembered than any thing that can he
substituted in its room.
Italy was not the only country into which the
algebraic analysis had hy this time found its
way : in Germany it had also made considerable
progress; and Stiphelius, in a hook of algebra,
published at Nuremberg in 1544, employed the
same numeral exponents of powers, both posi¬
tive and negative, which we now use, as far as
integer numbers are concerned; hut he did not
carry the solution of equations farther than the
second degree. He introduced the same charac¬
ters for plus and minus which are at present em¬
ployed.
Robert Recorde, an English mathematician,
published about this time, or a few years later,
the first English treatise on Algebra, and he
there introduced the same sign of equality which
is now in use.
The properties of algebraic equations were
discovered, however, very slowly. Pelitarius, a
French mathematician, in a treatise which hears
the date of 1558, is the first who observed that
the root of an equation is a divisor of the last
term; and he remarked also this curious pro¬
perty of numbers, that the sum of the cubes of
the natural numbers is the square of the sum of
the numbers themselves.
The knowledge of the solution of cubic equa¬
tions was still confined to Italy. Bombelli, a
mathematician of that country, gave a regular
treatise on Algebra, and considered, with very
particular attention, the irreducible case of Car¬
dan’s rule. He was the first who made the re¬
mark, that the problems belonging to that case can
always he resolved hy the trisection of an arch.1
Vieta was a very learned man, and an excel¬
lent mathematician, remarkable both for indus¬
try and invention. He was the first who em¬
ployed letters to denote the known as well as
the unknown quantities; so that it was with him
that the language of algebra first became capable
of expressing general truths, and attained to
that extension which has since rendered it such
a powerful instrument of investigation. He has
also given new demonstrations of the rule for
resolving cubic, and even biquadratic equations.
He also discovered the relation between the roots
of an equation of any degree, and the coefficients
of its terms, though only in the case where none
of the terms are wanting, and where all the roots
are real or positive. It is, indeed, extremely cu¬
rious to remark, how gradually the truths of this
1 A passage in Bombelli’s book, relative to the algebra of India, has become more interesting, from the information
concerning the science of that country, which has reached Europe within the last twenty years. He tells us, that he had
seen in the Vatican library, a manuscript of a certain Diophantus, a Greek author, which he admired so much, that he had
formed the design of translating it. He adds, that in this manuscript he had found the Indian authors often quoted; from
which it appeared that algebra was known to the Indians before it was known to the Arabians. Nothing, however, of all
this is to be found in the work of Diophantus, which was published about three years after the time when Bombelli wrote.
As it is, at the same time, impossible that he could be so much mistaken about a manuscript which he had particularly ex¬
amined, this passage remains a mystery, w'hich those who are curious about the ancient history of science would be very
glad to have unravelled. See Hutton’s History of Algebra.
DISSERTATION FOURTH.
559
sort came in sight. This proposition belonged
to a general truth, the greater part of which
remained yet to he discovered. Vieta’s treatises
were originally published about the year 1600,
and were afterwards collected into one volume
by Schooten, in 1646.
In speaking of this illustrious man, Vieta, we
must not omit his improvements in trigonome¬
try, and still less his treatise on Angular Sec¬
tions, which was a most important application
of algebra to investigate the theorems, and re¬
solve the problems of geometry. He also re¬
stored some of the books of Apollonius, in a
manner highly creditable to his own ingenuity,
but not perfectly in the taste of the Greek geo¬
metry; because, though the constructions are
elegant, the demonstrations are all synthetical.
About the same period, algebra became great¬
ly indebted to Albert Girard, a Flemish mathe¬
matician, whose principal work, Invention Nou-
velle en Algebre, was printed in 1669. This in¬
genious author perceived a greater extent, but
not yet the whole of the truth, partially discov¬
ered by Vieta, viz. the successive formation of
the coefficients of an equation from the sum of
the roots; the sum of their products taken two
and two; the same taken three and three, &c.
whether the roots be positive or negative. He
appears also to have been the first who under¬
stood the use of negative roots in the solution
of geometrical problems, and is the author of the
figurative expression, which gives to negative
quantities the name of quantities less than nothingi
a phrase that has been severely censured by those
who forget that there are correct ideas, which
correct language can hardly be made to express.
The same mathematician conceived the notion of
imaginary roots, and showed that the number of
the roots of an equation could not exceed the
exponent of the highest power of the unknown
quantity. He was also in possession of the very
refined and difficult rule, which forms the sums
of the powers of the roots of an equation from
the coefficients of its terms. This is the greatest
list of discoveries which the history of any alge¬
braist could yet furnish.
The person next in order, as an inventor in
algebra, is Thomas Harriot, an English mathe¬
matician, whose book, Artis Analyticee Praxis,
was published after his death, in 1631. This
book contains the genesis of all equations, by
the continued multiplication of simple equa¬
tions ; that is to say, it explains the truth in its
full extent, to which Vieta and Girard had been
approximating. By Harriot also, the method
of extracting the roots of equations was greatly
improved; the smaller letters of the alphabet,
instead of the capital letters employed by Vieta,
were introduced ; and by this improvement,
trifling, indeed, compared with the rest, the
form and exterior of algebraic expression were
brought nearer to those which are now in use.
I have been the more careful ta note very
particularly the degrees by which the properties
of equations were thus unfolded, because I think
it forms an instance hardly paralleled in science,
where a succession of able men, without going
wrong, advanced, nevertheless, so slowly in the
discovery of a truth which, when known, does
not seem to be of a very hidden and abstruse
nature. Their slow progress arose from this,
that they worked with an instrument, the use of
which they did not fully comprehend, and em¬
ployed a language which expressed more than
they were prepared to understand;—a language
which, under the notion, first of negative and
then of imaginary quantities, seemed to involve
such mysteries as the accuracy of mathematical
science must necessarily refuse to admit.
The distinguished author of whom I have
just been speaking was born at Oxford in 1560.
He was employed in the second expedition sent
out by Sir Walter Raleigh to Virginia, and on
his return published an account of that country.
He afterwards devoted himself entirely to the
study of the Mathematics; and it appears from
some of his manuscripts, lately discovered, that
he observed the spots of the sun as early as De¬
cember 1610, not more than a month later than
Galileo. He also made observations on Jupiter’s
satellites, and on the comets of 1607 and of
1618.1
1 The manuscripts which contain these observations, and probably many other things of great interest, are preserved in
the collection of the Earl of Egremont, having come into the possession of his family from Henry Percy, Earl of Northum¬
berland, a most liberal patron of science, with whom Harriot appears to have chiefly lived after his return from Virginia.
560
PRELIMINARY DISSERTATIONS.
The succession of discoveries above related
brought the algebraic analysis, abstractly con¬
sidered, into a state of perfection little short of
that which it has attained at the present mo¬
ment. It was thus prepared for the step which
was about to be taken by Descartes, and which
forms one of the most important epochas in the
history of the mathematical sciences. This was
the application of the algebraic analysis, to de¬
fine the nature, and investigate the properties,
of curve lines, and, consequently, to represent
the notion of variable quantity. It is often said
that Descartes was the first who applied algebra
to geometry; but this is inaccurate; for such
applications had been made before, particularly
by Vieta, in his treatise on Angular Sections.
The invention just mentioned is the undisputed
])roperty of Descartes, and opened up vast fields of
discovery for those who were to come after him.
The work in which this was contained is a
tract of no more than 106 quarto pages; and
there is probably no book of the same size which
has conferred so much and so just celebrity on
its author. It was first published in 1637.
In the first of the three books into which the
tract just mentioned is divided, the author begins
with the consideration of such geometrical pro¬
blems as may be resolved by circles and straight
lines; and explains the method of constructing
algebraic formulas, or of translating a truth from
the language of algebra into that of geometry.
He then proceeds to the consideration of the
problem, known among the ancients by the name
of the locus ad quatuor rectas, and treated of by
Apollonius and Pappus. The algebraic analysis
afforded a method of resolving this problem in
its full extent; and the consideration of it is
again resumed in the second book. The thing
required is, to find the locus of a point, from
which, if perpendiculars be drawn to four lines
given in position, a given function of these per¬
pendiculars, in which the variable quantities are
only of two dimensions, shall be always of the
same magnitude.1 Descartes shows the locus,
on this hypothesis, to be always a conic section;
and he distinguishes the cases in which it is a
circle, an ellipsis, a parabola, or a hyperbola.
It was an instance of the most extensive investi¬
gation which had yet been undertaken in geo¬
metry, though, to render it a complete solution
of the problem, much more detail was doubtless
necessary. The investigation is extended to the
cases where the function, which remains the
same, is of three, four, or five dimensions, and
where the locus is a line of a higher order,
though it may, in certain circumstances, become
a conic section. The lines given in position may
be more than four, or than any given number ;
and the lines drawn to them may either be per¬
pendiculars, or lines making given angles with
them. The same analysis applies to all the
cases; and this problem, therefore, afforded an
excellent example of the use of algebra in the
investigation of geometrical propositions. The
author takes notice of the unwillingness of the
ancients to transfer the language of arithmetic
into geometry, so that they were forced to have
recourse to very circuitous methods of expressing
those relations of quantity in which powers be¬
yond the third are introduced. Indeed, to de¬
liver investigation from those modes of expres¬
sion which involve the composition of ratios, and
to substitute in their room the multiplication of
the numerical measures, is of itself a very great
advantage, arising from the introduction of alge¬
bra into geometry.
In this book also, an ingenious method of
drawing tangents to curves is proposed by Des¬
cartes, as following from his general principles;
and it is an invention with which he appears to
have been particularly pleased. He says, “ Nec
verebor dicere, problema hoc non modo eorum
quae scio utilissimum et generalissimum esse,
sed etiam eorum quse in geometria scire unquam
desideraverim.”2 This passage is not a little
characteristic of Descartes, who was very much
disposed to think well of what he had done him¬
self, and even to suppose that it could not easily
1 It will easily be perceived, that the word function is not contained in the original enunciation of the problem. It is a
term but lately introduced into mathematical language, and affords here, as on many other occasions, a more general and
more concise expression than could be otherwise obtained.
2 Carte si i Geometria, p. 40.
DISSERTATION FOURTH.
561
be rendered more perfect. The truth, however,
is, that his method of drawing tangents is ex¬
tremely operose, and is one of those hasty views
which, though ingenious and even profound, re¬
quire to he vastly simplified, before they can he
reduced to practice. Fermat, the rival and
sometimes the superior of Descartes, was far
more fortunate with regard to this problem, and
his method of drawing tangents to curves is the
same in effect that has been followed by all the
geometers since his time; while that of Des¬
cartes, which could only be valued when the
other was unknown, has been long since entire¬
ly abandoned. The remainder of the second
book is occupied with the consideration of the
curves, which have been called the Ovals of Des¬
cartes, and with some investigations concerning
the centres of lenses; the whole indicating the
hand of a great master, and deserving the most
diligent study of those who would become ac¬
quainted with this great enlargement of mathe¬
matical science.
The third book of the geometry treats of the
construction of equations by geometric curves,
and it also contains a new method of resolving
biquadratic equations.
The leading principles of algebra were now
unfolded, and the notation was brought, from a
mere contrivance for abridging common lan¬
guage, to a system of symbolical writing, ad¬
mirably fitted to assist the mind in the exercise
of thought.
The happy idea, indeed, of expressing quanti¬
ty, and the operations on quantity, by conven¬
tional symbols, instead of representing the first
by real magnitudes, and enunciating the second
in words, could not but make a great change on
the nature of mathematical investigation. The
language of Mathematics, whatever may be its
form, must always consist of two parts; the one
denoting quantities simply, and the other denot¬
ing the manner in which the quantities are com¬
bined, or the operations understood to be per¬
formed on them. Geometry expresses the first
of these by real magnitudes, or by what may be
called natural signs; a line by a line, an angle
by an angle, an area by an area, &c.; and it de¬
scribes the latter by words. Algebra, on the
other hand, denotes both quantity, and the
DISS. IV., PART I.
operations on quantity, by the same system of
conventional symbols. Thus, in the expression
xz—a x2 bz — o, the letters a, b, x, denote
quantities, but the terms x3, a x2, &c. denote
certain operations performed on those quantities,
as well as the quantities themselves; x3 is the
quantity x raised to the cube; and ax2 the same
quantity x raised to the square, and then multi¬
plied into a, &c.; the combination, by addition
or subtraction, being also expressed by the signs
+ and —.
Now, it is when applied to this latter purpose
that the algebraic language possesses such ex¬
clusive excellence. The mere magnitudes them¬
selves might be represented by figures, as in
geometry, as well as in any way whatever ; but
the operations they are to be subjected to, if
described in words, must be set before the mind
slowly, and in succession, so that the impression
is weakened, and the clear apprehension ren¬
dered difficult. In the algebraic expression, on
the other hand, so much meaning is concentrat¬
ed into a narrow space, and the impression
made by all the parts is so simultaneous, that
nothing can be more favourable to the exertion
of the reasoning powers, to the continuance of
their action, and their security against error.
Another advantage resulting from the use of the
same notation, consists in the reduction of all
the different relations among quantities to the
simplest of those relations, that of equality, and
the expression of it by equations. This gives a
great facility of generalization, and of compar¬
ing quantities with one another. A third arises
from the substitution of the arithmetical opera¬
tions of multiplication and division, for the geo¬
metrical method of the composition and resolu¬
tion of ratios. Of the first of these, the idea is
so clear, and the work so simple ; of the second,
the idea is comparatively so obscure, and the
process so complex, that the substitution of toe
former for the latter could not but be accom¬
panied with great advantage. This is, in¬
deed, what constitutes the great difference in
practice between the algebraic and the geome¬
tric method of treating quantity. When the
quantities are of a complex nature, so as to go
beyond what in algebra is called the third
power, the geometrical expression is so circuit-
562
PRELIMINARY DISSERTATIONS.
ous and involved, that it renders the reasoning
most laborious and intricate. The great facili¬
ty of generalization in algebra, of deducing one
thing from another, and of adapting the analy¬
sis to every hind of research, whether the (quan¬
tities he constant or variable, finite or infinite,
depends on this principle more than any other.
Few of the early algebraists seem to have been
aware of these advantages.
The use of the signs plus and minus has given
rise to some dispute. These signs were at first
used, the one to denote addition, the other sub¬
traction, and for a long time were applied to no
other purpose. But as, in the multiplication of
a quantity, consisting of parts connected by
those signs, into another quantity similarly
composed, it was always found, and could be
universally demonstrated, that, in uniting the
particular products of which the total was made
up, those of which both the factors had the sign
minus before them, must be added into one sum
with those of which all the factors had the sign
plus, while those of which one of the factors
had the sign plus, and the other the sign minus,
must be subtracted from the same,—this gene¬
ral rule came to be more simply expressed by
saying, that in multiplication like signs gave
plus, and that unlike signs gave minus.
Hence the signs plus and minus were con¬
sidered, not as merely denoting the relation of
one quantity to another placed before it, but, by
a kind of fiction, they were considered as de¬
noting qualities inherent in the quantities to the
names of which they were prefixed. This fic¬
tion was found extremely useful, and it was
evident that no error could arise from it. It
was necessary to have a rule for determining
the sign belonging to a product, from the signs
of the factors composing that product, inde¬
pendently of every other consideration; and
this was precisely the purpose for which the
above fiction was introduced. So necessary is
this rule in the generalizations of algebra, that
we meet with it in Diophantus, notwithstanding
the imperfection of the language he employed;
for he states, that As/^/g into As/^/g gives
'IVagg/g, &c. The reduction, therefore, of the
operations on quantity to an arithmetical form,
necessarily involves this use of the signs plus or
minus ; that is, their application to denote some¬
thing like absolute qualities in the objects they
collect together. The attempts to free algebra
from this use of the signs have of course failed,
and must ever do so, if we would preserve to
that science the extent and facility of its opera¬
tions.
Even the most scrupulous purist in mathema¬
tical language must admit, that no real error is
ever introduced by employing the signs in this
most abstract sense. If the equation -j- px*
+ qx + r = o, be said to have one positive and
two negative roots, this is certainly as excep¬
tionable an application of the term negative as
any that can be proposed; yet, in reality, it
means nothing but this intelligible and simple
truth, that x* + px* + qx + r = (x — a)
(x + b) (a? + c); or that the former of these
quantities is produced by the multiplication of
the three binomial factors, x — a, x b, x c.
We might say the same nearly as to imaginary
roots : they show that the simple factors cannot
be found, but that the quadratic factors may be
found; and they also point out the means of
discovering them.
The aptitude of these same signs to denote
contrariety of position among geometric magni¬
tudes, makes the foregoing application of them
infinitely more extensive and more indispensable.
From the same source arises the great simpli¬
city introduced into many of the theorems and
rules of the mathematical sciences. Thus, the
rule for finding the latitude of a place from the
sun’s meridian altitude, if we employ the signs
plus and minus for indicating the position of the
sun and of the place relatively to the equator, is
enunciated in one simple proposition, which in¬
cludes every case, without any thing either com¬
plex or ambiguous. But if this is not done,—
if the signs plus and minus are not employed,
there must be at least two rules; one when the
sun and place are on the same side of the equa¬
tor, and another when they are on different
sides. In the more complicated calculations of
spherical trigonometry, this holds still more re¬
markably. When one would accommodate such
rules to those who are unacquainted with the
use of the algebraic signs, they are perhaps not
to be expressed in less than four, or even six
DISSERTATION FOURTH.
563
different propositions; whereas, if the use of
these signs is supposed, the whole is compre¬
hended in a single sentence. In such cases, it
is obvious that both the memory and under¬
standing derive great advantage from the use of
the signs, and profit by a simplification, which
is the work entirely of the algebraic language,
and cannot he imitated by any other.
That I might not interrupt the view of im¬
provements so closely connected with one ano¬
ther, I have passed over one of the discoveries,
which does the greatest honour to the seventeenth
century, and which took place near the beginning
of it.
As the accuracy of astronomical observation
had been continually advancing, it was necessary
that the correctness of trigonometrical calcula¬
tion, and of course its difficulty, should advance
in the same proportion. The signs and tangents
of angles could not be expressed with sufficient
correctness without decimal fractions, extending
to five or six places below unity; and when to
three such numbers a fourth proportional was to
he found, the work of multiplication and division
became extremely laborious. Accordingly, in
the end of the sixteenth century, the time and
labour consumed in such calculations had become
excessive, and were felt as extremely burdensome
by the mathematicians and astronomers all over
Europe. Napier of Merchiston, whose mind
seems to have been peculiarly turned to arithme¬
tical researches, and who was also devoted to
the study of astronomy, had early sought for the
means of relieving himself and others from this
difficulty. He had viewed the subject in a varie¬
ty of lights, and a number of ingenious devices
had occurred to him, by which the tediousness
of arithmetical operations might, more or less
completely, be avoided. In the course of these
attempts, he did not fail to observe, that when¬
ever the numbers to be multiplied or divided
were terms of a geometrical progression, the pro¬
duct or the quotient must also be a term of that
progression, and must occupy a place in it point¬
ed out by the places of the given numbers, so
that it might be found from mere inspection, if
the progression were far enough continued. If,
for instance, the third term of the progression
were to be multiplied by the seventh, the pro¬
duct must be the tenth; and if the twelfth were
to be divided by the fourth, the quotient must
be the eighth; so that the multiplication and
division of such terms was reduced to the addi¬
tion and subtraction of the numbers which in¬
dicated their places in the progression.
This observation, or one very similar to it,
was made by Archimedes, and was employed by
that great geometer to convey an idea of a num¬
ber too vast to be correctly expressed by the
arithmetical notation of the Greeks. Thus far,
however, there was no difficulty; and the dis¬
covery might certainly have been made by men
much inferior either to Napier or Archimedes.
What remained to be done, what Archimedes
did not attempt, and what Napier completely
performed, involved two great difficulties. It is
plain, that the resource of the geometrical pro¬
gression was sufficient, when the given numbers
were terms of that progression; but if they were
not, it did not seem that any advantage could
be derived from it. Napier, however, perceiv¬
ed, and it was by no means obvious, that all
numbers whatsoever might be inserted in the
progression, and have their places assigned in it.
After conceiving the possibility of this, the next
difficulty was, to discover the principle, and to
execute the arithmetical process, by which these
places were to be ascertained. It is in these two
points that the peculiar merit of his invention
consists; and at a period when the nature of
series, and when every other resource of which
he could avail himself, were so little known, his
success argues a depth and originality of thought
which, I am persuaded, have rarely been sur¬
passed.
The way in which he satisfied himself that
all numbers might be intercalated between the
terms of the given progression, and by which he
found the places they must occupy, was founded
on a most ingenious supposition; that of two
points describing two different lines, the one with
a constant velocity, and the other with a veloci¬
ty always increasing in the ratio of the space the
point had already gone over: the first of these
would generate magnitudes in arithmetical, and
the second magnitudes in geometrical progression.
It is plain, that all numbers whatsoever would
find their places among the magnitudes so gene-
564
preliminary dissertations.
rated; and, indeed, this view of the subject is as
simple and profound as any which, after two
hundred years, has yet presented itself to mathe¬
maticians. The mode of deducing the lesults
has been simplified; but it can hardly be said
that the principle has been more clearly deve¬
loped.
I need not observe, that the numbers which
indicate the places of the terms of the geome¬
trical progression are called by Napier the loga¬
rithms of those terms.
Various systems of logarithms, it is evident,
may be constructed according to the geometrical
progression assumed; and of these, that which
was first contrived by Napier, though the
simplest, and the foundation of the rest, was not
so convenient for the purposes of calculation, as
one which soon afterwards occurred, both to him¬
self and his friend Briggs, by whom the actual
calculation was performed. The new system of
logarithms was an improvement, practically
considered; but in as far as it was connected
with the principle of the invention, it is only of
secondary consideration. The original tables
had been also somewhat embarrassed by too
close a connection between them and trigono¬
metry. The new tables were free from this in¬
convenience.
It is probable, however, that the greatest in¬
ventor in science was never able to do more
than to accelerate the progress of discovery, and
to anticipate what time, “ the author of authors,”
would have gradually brought to light. Though
logarithms had not been invented by Napier,
they would have been discovered in the progress
of the algebraic analysis, when the arithmetic
of powers and exponents, both integral and frac¬
tional, came to be fully understood. The idea
of considering all numbers as powers of one
given number would then have readily occurred,
and the doctrine of series would have greatly
facilitated the calculations which it was neces¬
sary to undertake. Napier had none of these
advantages, and they were all supplied by the
resources of his own mind. Indeed, as there
never was any invention for which the state of
knowledge had less prepared the way, there
never was any where more merit fell to the
share of the inventor.
His good fortune, also, not less than his great
sagacity, may be remarked. Had the invention
of logarithms been delayed to the end of the
seventeenth century, it would have come about
without effort, and would not have conferred on
the author the high celebrity which Napier so
justly derives from it. In another respect he
has also been fortunate. Many inventions have
been eclipsed or obscured by new discoveries;
or they have been so altered by subsequent im¬
provements, that their original form can hardly
be recognised, and, in some instances, has been
entirely forgotten. This has almost always hap¬
pened to the discoveries made at an early period
in the progress of science, and before their prin¬
ciples were fully unfolded. It has been quite
otherwise with the invention of logarithms,
which came out of the hands of the author so
perfect, that it has never received but one ma¬
terial improvement,—that which it derived, as
has just been said, from the ingenuity of his
friend in conjunction with his own. Subsequent
improvements in science, instead of offering any
thing that could supplant this invention, have
only enlarged the circle to which its utility
extended. Logarithms have been applied to
numberless purposes, which were not thought
of at the time of their first construction. Even
the sagacity of their author did not see the
immense fertility of the principle he had dis¬
covered : he calculated his tables merely to
facilitate arithmetical, and chiefly trigonome¬
trical computation; and little imagined that
he was at the same time constructing a scale
whereon to measure the density of the strata
of the atmosphere, and the heights of moun¬
tains ; that he was actually computing the areas
and the lengths of innumerable curves, and
was preparing for a calculus which was yet
to be discovered, many of the most refined and
most valuable of its resources. Of Napier,
therefore, if of any man, it may safely be pro¬
nounced, that his name will never be eclipsed
by any one more conspicuous, or his invention
superseded by any thing more valuable.
As a geometrician, Napier has left behind him
a noble monument in the two trigonometrical
theorems, which are known by his name, and
which appear first to have been communicated
DISSERTATION FOURTH.
565
in writing to Cavalleri, who has mentioned them cularly adapted to logarithmic calculation. They
with great eulogy.1 2 They are theorems not a were published in the Canon Mirificus Logarith-
little difficult, and of much use, as being parti- morum, at Edinburgh, in 1614.*
SECTION II.
EXPERIMENTAL INVESTIGATION.
In this section I shall begin with a short view analysis of the Novum Organum ; and shall then
of the state of Physical Knowledge before the inquire how far the principles established in that
introduction of the Inductive Method; I shall work have actually contributed to the advance-
next endeavour to explain that method by an ment of Natural Philosophy.
1. ANCIENT PHYSICS.
Though the phenomena of the material world
could not but early excite the curiosity of a
being who, like man, receives his strongest im¬
pressions from without, yet an accurate know¬
ledge of those phenomena, and their laws, was
not to be speedily acquired. The mere extent
and variety of the objects were, indeed, such ob¬
stacles to that acquisition, as could not be sur¬
mounted but in the course of many ages. Man
could not at first perceive from what point he
must begin his inquiries, in what direction he
must carry them on, or by what rules he must
be guided. He was like a traveller going forth
to explore a vast and unknown wilderness, in
which a multitude of great and interesting ob¬
jects presented themselves on every side, while
there was no path for him to follow, no rule to
direct his survey, and where the art of observ¬
ing, and the instruments of observation, must
equally be the work of his own invention. In
these circumstances, the selection of the objects
to be studied was the effect of instinct rather than
of reason, or of the passions and emotions, more
than of the understanding. When things new,
and unlike those which occurred in the course
of every day’s experience, presented themselves,
they excited wonder or surprise, and created an
anxiety to discover some principle which might
connect them with the appearances commonly
observed. About these last, men felt no desire
to be further informed; but when the common
order of things was violated, and something new
or singular was produced, they began to exa¬
mine into the fact, and attempted to inquire into
the cause. Nobody sought to know why a
stone fell to the ground, why smoke ascended,
or why the stars revolved round the earth. But
if a fiery meteor shot across the heavens,—if
the flames of a volcano burst forth,—or if an
earthquake shook the foundations of the world,
terror and curiosity were both awakened; and
when the former emotion had subsided, the
latter was sure to become active. Thus, to
trace a resemblance between the events with
which the observer was most familiar, and
those to which he was less accustomed, and
which had excited his wonder, was the first ob¬
ject of inquiry, and produced the first advances
towards generalization and philosophy.*
This principle, which it were easy to trace,
1 Wallis, Opera Math. tom. II. p. 875.
2 A reprint of the Canon Mirificus, from the original edition, is given in the sixth volume of the great Thesaurus, m
which Baron Maseres, with his usual zeal and intelligence, has collected and illustrated every thing ol importance that has
been written on the subject of logarithms. See Scriptores Logarithmici, 4to. vol. VI. p. 475.
» La maraviglia
Dell’ ignoranza d la figlia,
E del sapere
La madre.
566
PRELIMINARY DISSERTATIONS.
from tribes the most rude and barbarous, to na¬
tions the most highly refined, was what yielded
the first attempts toward classification and ar¬
rangement, and enabled man, out of individuals
subject to perpetual change, to form certain
fixed and permanent objects of knowledge,—
the species, genera, orders, and classes, into
which he has distributed these individuals. By
this effort of mental abstraction, he has created
to himself a new and intellectual world, free
from those changes and vicissitudes to which
all material things are destined. This, too, is a
work not peculiar to the philosopher, but, in a
certain degree, is performed by every man who
compares one thing with another, and who em¬
ploys the terms of ordinary language.
Another great branch of knowledge is occu¬
pied, not about the mere arrangement and clas¬
sification of objects, but about events or changes,
the laws which those changes observe, and the
causes by which they are produced. In a sci¬
ence which treated of events and of change, the
nature and properties of motion came of course
to be studied, and the ancient philosophers na¬
turally enough began their inquiries with the
definition of motion, or the determination of
that in which it consists. Aristotle’s definition
is highly characteristical of the vagueness and
obscurity of his physical speculations. He calls
motion “ the act of a being in power, as far
as in powerwords to which it is impossi¬
ble that any distinct idea can ever have been
annexed.
The truth is, however, that the best defini¬
tion of motion can be of very little service in
Physics. Epicurus defined it to be the “ change
of place,” which is, no doubt, the simplest and
best definition that can be given; but it must,
at the same time, be confessed, that neither he,
nor the moderns who have retained his defini¬
tion, have derived the least advantage from it
in their subsequent researches. The properties,
or, as they are called, the laws of motion, can¬
not be derived from mere definition ; they must
be sought for in experience and observation, and
are not to be found without a diligent compari¬
son, and scrupulous examination of facts. Of
such an examination, neither Aristotle, nor any
other of the ancients, ever conceived the ne¬
cessity ; and hence those latvs remained quite
unknown throughout all antiquity.
When the laws of motion were unknown, the
other parts of Natural Philosophy could make no
great advances. Instead of conceiving that there
resides in body a natural and universal tendency
to persevere in the same state, whether of rest
or of motion, they believed that terrestrial bo¬
dies tended naturally either to fall to the ground,
or to ascend from it, till they attained their own
place; but that, if they were impelled by an ob¬
lique force, then their motion became unnatural
or violent, and tended continually to decay. With
the heavenly bodies, again, the natural motion
was circular and uniform, eternal in its course,
but perpetually varying in its direction. Thus,
by the distinction between natural and violent
motion among the bodies of the earth, and the
distinction between what we may call the laws
of motion in terrestrial and celestial bodies, the
ancients threw into all their reasonings upon this
fundamental subject a confusion and perplexi¬
ty, from which their philosophy never was de¬
livered.
There was, however, one part of physical
knowledge in which their endeavours were at¬
tended with much better success, and in which
they made important discoveries. This was in
the branch of mechanics which treats of the
action of forces in equilibria, and producing not
motion but rest; a subject which may be under¬
stood, though the laws of motion are unknown.
The first writer on this subject is Archimedes.
He treated of the lever, and of the centre of
gravity; and has shown that there will be an
equilibrium between two heavy bodies connect¬
ed by an inflexible rod or lever, when the point
in which the lever is supported is so placed be¬
tween the bodies, that their distances from it
are inversely as their weights. Great ingenuity
is displayed in this demonstration ; and it is re¬
markable, that the author borrows no principle
from experiment, but establishes his conclusion
entirely by reasoning a priori. He assumes, in¬
deed, that equal bodies, at the ends of the equal
arms of a lever, will balance one another; and
also, that a cylinder, or parallelopiped of homo¬
geneous matter, will be balanced about its centre
of magnitude. These, however, are not inferences
DISSERTATION FOURTH.
567
from experience; they are, properly speaking,
conclusions deduced from the principle of the
sufficient reason.
The same great geometer gave a beginning to
the science of hydrostatics, and discovered the
law which determines the loss of weight sustain¬
ed by a body on being immersed in water, or in
any other fluid. His demonstration rests on a
principle, which he lays down as a postulatum,
that, in water, the parts which are less pressed
are always ready to yield in any direction to
those that are more pressed; and from this, by
the application of mathematical reasoning, the
whole theory of floating bodies is derived. The
above is the same principle on which the mo¬
dern writers on hydrostatics proceed; they give
it, not as a postulatum, hut as constituting the
definition of a fluid.
Archimedes, therefore, is the person who first
made the application of Mathematics to Natural
Philosophy. No individual, perhaps, ever laid
the foundation of more great discoveries than that
geometer, of whom Wallis has said with so much
truth, “ Yir stupendse sagacitatis, qui prima
fundamenta posuit inventionum fere omnium, in
quibus promovendis setas nostra gloriatur.”
The mechanical inquiries, begun by the geo¬
meter of Syracuse, were extended by Ctesibius
and Hero; by Anthemius of Tralles ; and, last¬
ly, by Pappus Alexandrinus. Ctesibius and
Hero were the first who analyzed mechanical
engines, reducing them all to combinations of
five simple mechanical contrivances, to which
they gave the name of Awa/uiz, or Powers, the
same which they retain at the present moment.
Even in mechanics, however, the success of
these investigations was limited; and failed in
those cases where the resolution of forces is ne¬
cessary, that principle being then entirely un¬
known. Hence the force necessary to sustain a
body on an inclined plane, is incorrectly deter¬
mined by Pappus, and serves to mark a point
to which the mechanical theories of antiquity
did not extend.
In another department of physical knowledge,
astronomy, the endeavours of the ancients were
also accompanied with success. I do not here
speak of their astronomical theories, which were,
indeed, very defective, but of their discovery of
the apparent motions of the heavenly bodies,
from the observations begun by Hipparchus, and
continued by Ptolemy. In this their success
was great; and while the earth was supposed to
be at rest, and while the instruments of obser¬
vation had but a very limited degree of accuracy,
a nearer approach to the truth was probably not
within the power of human ingenuity. Mathe¬
matical reasoning was very skilfully applied;
and no men whatever, in the same circum¬
stances, are likely to have performed more than
the ancient astronomers. They succeeded, be¬
cause they were observers, and examined care¬
fully the motions which they treated of. The
philosophers, again, who studied the motion of
terrestrial bodies, either did not observe at all,
or observed so slightly, that they could obtain
no accurate knowledge; and in general they
knew just enough of the facts to be misled by
them.
The opposite ways which the ancients thus
took to study the Heavens and the Earth, obser¬
ving the one, and dreaming, as one may say,
over the other, though a striking inconsistency,
is not difficult to be explained.
No information at all could be obtained in as¬
tronomy, without regular and assiduous obser¬
vation, and without instruments capable of mea¬
suring angles, and of measuring time, either di¬
rectly or indirectly. The steadiness and regu¬
larity of the celestial motions seemed to invite
the most scrupulous attention. On the other
hand, as terrestrial objects were always at hand,
and spontaneously falling under men’s view, it
seemed unnecessary to take much trouble to be¬
come acquainted with them; and as for applying
measures, their irregularity appeared to render
every idea of such proceeding nugatory. The
Aristotelian philosophy particularly favoured
this prejudice, by representing the earth, and
all things on its surface, as full of irregularity
and confusion, while the principles of heat and
cold, dryness and moisture, were in a state of
perpetual warfare. The unfortunate division of
motion into natural and violent, and the dis¬
tinction, still more unfortunate, between the pro¬
perties of motion and of body, in the heavens and
on the earth, prevented all intercourse between
the astronomer and the naturalist, and all trans-
568
PRELIMINARY DISSERTATIONS.
ference of the maxims of the one to the specula¬
tions of the other.
Though, on account of this inattention to ex¬
periment, nothing like the true system of Natu¬
ral Philosophy was known to the ancients, there
are, nevertheless, to he found in their wiitings
many brilliant conceptions, several fortunate
conjectures, and gleams of the light which was
afterwards to be so generally diffused.
Anaxagoras and Empedocles, for example,
taught that the moon shines by light borrowed
from the sun, and were led to that opinion, not
only from the phases of the moon, hut from its
light being weak, and unaccompanied by heat.
That it was a habitable body, like the earth,
appears to be a doctrine as old as Orpheus;
some lines, ascribed to that poet, representing
the moon as an earth, with mountains and cities
on its surface.
Democritus supposed the spots on the face of
the moon to arise from the inequalities of the
surface, and from the shadows of the more ele¬
vated parts projected on the plains. Every one
knows how conformable this is to the discoveries
made by the telescope.
Plutarch considers the velocity of the moon’s
motion as the cause which prevents that body
from falling to the earth, just as the motion of
a stone in a sling prevents it from falling to the
ground. The comparison is, in a certain de¬
gree, just, and clearly implies the notion of
centrifugal force; and gravity may also he con¬
sidered as pointed at for the cause which gives
the moon a tendency to the earth. Here, there¬
fore, a foundation was laid for the true philo¬
sophy of the celestial motions; hut it was laid
without effect. It was merely the conjecture
of an ingenious mind, wandering through the
regions of possibility, guided by no evidence,
and having no principle which could give sta¬
bility to its opinions. Democritus, and the
authors of that physical system which Lucretius
has so beautifully illustrated, were still more
fortunate in some of their conjectures. They
taught that the Milky Way is the light of a great
number of small stars, very close to one another; a
magnificent conception, which the latest improve¬
ments of the telescope have fully verified. Yet, as
if to convince us that they derived this knowledge
from no pure or certain source, the same philo¬
sophers maintained, that the sun and the moon
are bodies no larger than they appear to us to he.
Very just notions concerning comets were
entertained by some of the ancients. The Chal¬
deans considered those bodies as belonging to
the same order with the planets; and this was
also the opinion of Anaxagoras, Pythagoras,
and Democritus. The remark of Seneca on
this subject is truly philosophical, and contains
a prediction which has been fully accomplished:
ii Why do we wonder that comets, which are
so rare a spectacle in the world, observe laws
which to us are yet unknown, and that the be¬
ginning and end of motions, so seldom observed,
are not yet fully understood?”—Veniet tempus,
quo ista quce nunc latent, in lucem dies extrahat, et
longioris cevi diligentia: ad inquisitionem tantorum
cetas una non sufficit. Veniet tempos, quo posteri
nostri tam aperta nos nescisse mirentur.1
It was, however, often the fate of such truths
to give way to error. The comets, which these
ancient philosophers had ranked so justly with
the stars, were degraded by Aristotle into me¬
teors floating in the earth’s atmosphere; and
this was the opinion concerning them which ul¬
timately prevailed.
But, notwithstanding the above, and a few
other splendid conceptions which shine through
the obscurity of the ancient Physics, the system,
taken on the whole, was full of error and in¬
consistency. Truth and falsehood met almost
on terms of equality; the former, separated from
its root, experience, found no preference above
the latter; to the latter, in fact, it was gene¬
rally forced to give way, and the dominion of
error was finally established.
One ought to listen, therefore, with caution
to the encomiums sometimes bestowed on the
philosophy of those early ages. If these enco¬
miums respected only the talents, the genius,
the taste of the great masters of antiquity, we
would subscribe to them without any apprehen-
1 Nat. Qucest. lib. vii. cap. xxv.
DISSERTATION FOURTH.
569
sion of going beyond the truth. But if they ex¬
tend to the methods of philosophizing, and the
discoveries actually made, we must he excused
for entering our dissent, and exchanging the
language of panegyric for that of apology. The
infancy of science could not he the time when
its attainments were the highest; and before
we suffer ourselves to be guided by the vene¬
ration of antiquity, we ought to consider in what
real antiquity consists. With regard to the pro¬
gress of knowledge and improvement, <{ we are
more ancient than those who went before us.”1
The human race has now more experience than
in the generations that are past, and of course
may be expected to have made higher attain¬
ments in science and philosophy. Compared
with Natural Philosophy, as it now exists, the
ancient Physics are rude and imperfect. The
speculations contained in them are vague and
unsatisfactory, and of little value, but as they
elucidate the history of the errors and illusions
to which the human mind is subject. Science
was not merely stationary, but often retrograde;
the earliest opinions were frequently the best;
2. NOVUM
The defects which have been ascribed to the
ancient Physics were not likely to be correct¬
ed in the course of the middle ages. It is
true, that during those ages a science of pure
experiment had made its appearance in the
world, and might have been expected to remedy
the greatest of these defects, by turning the at¬
tention of philosophers to experience and obser-
vation. This effect, however, was far from be¬
ing immediately produced; and none who pro¬
fessed to be in search of truth ever wandered
over the regions of fancy, in paths more devious
and eccentric, than the first experimenters in
Chemistry. They had become acquainted with a
series of facts so unlike to any thing already
known, that the ordinary principles of belief
were shaken or subverted, and the mind laid
open to a degree of credulity far beyond any
with which the philosophers of antiquity could
be reproached. An unlooked-for extension of
and the reasonings of Democritus and Anaxa¬
goras were in many instances more solid than
those of Plato and Aristotle. Extreme credu¬
lity disgraced the speculations of men who,
however ingenious, were little acquainted with
the laws of nature, and unprovided with the
great criterion by which the evidence of testi¬
mony can alone be examined. Though obser¬
vations were sometimes made, experiments were
never instituted; and philosophers who were
little attentive to the facts which spontaneously
offered, did not seek to increase their number
by artificial combinations. Experience, in those
ages, was a light which darted a few tremulous
and uncertain rays on some small portions of
the field of science; but men had not acquired
the power over that light which now enables
them to concentrate its beams, and to fix them
steadily on whatever object they wish to ex¬
amine. This power is what distinguishes the
modern Physics, and is the cause why later phi¬
losophers, without being more ingenious than
their predecessors, have been infinitely more
successful in the study of nature.
ORGANUM.
human power had taken place; its limits were
yet unknown; and the boundary between the
possible and the impossible was no longer to be
distinguished. The adventurers in an unexplor¬
ed country, given up to the guidance of imagi¬
nation, pursued objects which the kindness, no
less than the wisdom of nature, has rendered
unattainable by man ; and in their speculations
peopled the air, the earth, and all the elements,
with spirits and genii, the invisible agents des¬
tined to connect together all the facts which
they knew, and all those which they hoped to
discover. Chemistry, in this state, might be
said to have an elective attraction for all that
was most absurd and extravagant in the other
parts of knowledge; alchemy was its immediate
offspring, and it allied itself in succession with
the dreams of the Cabalists, the Rosicrucians,
and the Theosophers. Thus a science, founded
in experiment, and destined one day to afford
4 c
DISS IV., PART I.
1 Bacon.
570
PRELIMINARY DISSERTATIONS.
such noble examples of its use, exhibited for se¬
veral ages little else than a series of illusory
pursuits, or visionary speculations, while now
and then a fact was accidentally discovered.
Under the influence of these circumstances
arose Paracelsus, Van Helmont, Fludd, Cardan,
and several others, conspicuous no less for the
weakness than the force of their understand¬
ings ; men who united extreme credulity, the
most extravagant pretensions, and the most ex¬
cessive vanity, with considerable powers of in¬
vention, a complete contempt for authority, and
a desire to consult experience; but destitute of
the judgment, patience, and comprehensive views,
without which the responses of that oracle are
never to he understood. Though they appealed
to experience, and disclaimed subjection to the
old legislators of science, they were in too great
haste to become legislators themselves, and to
deduce an explanation of the whole phenomena
of nature from a few facts, observed without ac¬
curacy, arranged without skill, and never com¬
pared or confronted with one another. For¬
tunately, however, from the turn which their
inquiries had taken, the ill done by them has
passed away, and the good has become perma¬
nent. The reveries of Paracelsus have disap¬
peared, but his application of Chemistry to Phar¬
macy has conferred a lasting benefit on the
world. The Archceus of Van Helmont, and the
army of spiritual agents with which the disco¬
very of elastic fluids had filled the imagination
of that celebrated empiric, are laughed at, or
forgotten; but the fluids which he had the sa¬
gacity to distinguish, form, at the present mo¬
ment, the connecting principles of the new Che¬
mistry.
Earlier than any of the authors just named,
but in a great measure under the influence of
the same delusions, Roger Bacon appears to
have been more fully aware than any of them of
the use of experiment, and of mathematical rea¬
soning, in physical and mechanical inquiries.
But, in the thirteenth century, an appeal from
the authority of the schools, even to nature her¬
self, could not be made with impunity. Bacon,
accordingly, incurred the displeasure both of
the University and of the Church; and this forms
one of his claims to the respect of posterity, as
it is but fair to consider persecution inflicted by
the ignorant and bigoted as equivalent to praise
bestowed by the liberal and enlightened.
Much more recently, Gilbert, in his treatise
on the Magnet, had given an example of an ex¬
perimental inquiry, carried on with more cor¬
rectness, and more enlarged views, than had
been done by any of his predecessors. Never¬
theless, in the end of the sixteenth century, it
might still be affirmed, that the situation of the
great avenue to knowledge was fully understood
by none, and that its existence, to the bulk of
philosophers, was utterly unknown.
It was about this time that Francis Bacon
(Lord Verulam) began to turn his powerful and
creative mind to contemplate the state of human
knowledge, to mark its imperfections, and to
plan its improvement. One of the considera¬
tions which appears to have impressed his mind
most forcibly, was the vagueness and uncertain¬
ty of all the physical speculations then existing,
and the entire want of connection between the
sciences and the arts.
Though these two things are in their nature
so closely united, that the same truth which is a
principle in science becomes a rule in art, yet
there was at that time hardly any practical im¬
provement which had arisen from a theoretical
discovery. The natural alliance between the
knowledge and the power of man seemed entire¬
ly interrupted; nothing was to be seen of the
mutual support which they ought to afford to one
another; the improvement of art was left to the
slow and precarious operation of chance, and
that of science to the collision of opposite opin¬
ions.
cc But whence,” said Bacon, can arise such
vagueness and sterility in all the physical systems
which have hitherto existed in the world ? It is
not certainly from any thing in nature itself;
for the steadiness and regularity of the laws by
which it is governed, clearly mark them out as
objects of certain and precise knowledge. Nei¬
ther can it arise from any want of ability in
those who have pursued such inquiries, many of
whom have been men of the highest talent and
genius of the ages in which they lived; and it
can, therefore, arise from nothing else but the
perverseness and insufficiency of the methods
DISSERTATION FOURTH.
571
that have been pursued. Men have sought to
make a world from their own conceptions, and
to draw from their own minds all the materials
which they employed; but if, instead of doing
so, they had consulted experience and observa¬
tion, they would have had facts, and not opinions,
to reason about, and might have ultimately arriv¬
ed at the knowledge of the laws which govern
the material world.”
“ As things are at present conducted,” he
adds, “'a sudden transition is made from sensible
objects and particular facts to general proposi¬
tions, which are accounted principles, and round
which, as round so many fixed poles, disputation
and argument continually revolve. From the
propositions thus hastily assumed, all things are
derived, by a process compendious and precipi¬
tate, ill suited to discovery, but wonderfully ac¬
commodated to debate. The way that promises
success is the reverse of this. It requires that
we should generalize slowly, going from particu¬
lar things to those that are but one step more
general; from those to others of still greater ex¬
tent, and so on to such as are universal. By
such means, we may hope to arrive at principles,
not vague and obscure, but luminous and well
defined, such as nature herself will not refuse
to acknowledge.”
Before laying down the rules to be observed
in this inductive process, Bacon proceeds to
enumerate the causes of error,—the Idols, as he
terms them, in his figurative language, or false
divinities, to which the mind had so long been
accustomed to bow. He considered this enume¬
ration as the more necessary, that the same idols
were likely to return, even after the reformation
of science, and to avail themselves of the real
discoveries that might have been made, for giv¬
ing a colour to their deceptions.
These idols he divides into four classes, to
which he gives names, fantastical, no doubt,
but, at the same time, abundantly significant:
Idola Tribus, Idols of the Tribe ;
 Specus,  of the Den ;
 Fori,  of the Forum ;
 Theatri,  of the Theatre.
1. The Idols of the Tribe, or of the race, are the
causes of error founded on human nature in ge¬
neral, or on principles common to all mankind.
“ The mind,” he observes, “ is not like a plain
mirror, which reflects the images of things ex¬
actly as they are; it is like a mirror of an uneven
surface, which combines its own figure with the
figures of the object it represents.”1
Among the idols of this class, we may reckon
the propensity which there is in all men to find
in nature a greater degree of order, simplicity,
and regularity, than is actually indicated by ob¬
servation. Thus, as soon as men perceived the
orbits of the planets to return into themselves,
they immediately supposed them to be perfect
circles, and the motion in those circles to be uni¬
form ; and to these hypotheses, so rashly and
gratuitously assumed, the astronomers and ma¬
thematicians of all antiquity laboured incessantly
to reconcile their observations.
The propensity which Bacon has here charac¬
terized so well, is the same that has been, since
his time, known by the name of the spirit of sys¬
tem. The prediction, that the sources of error
would return, and were likely to infest science
in its most flourishing condition, has been fully
verified with respect to this illusion, and in the
case of sciences which had no existence at the
time when Bacon wrote. When it was ascer¬
tained, by observation, that a considerable part
of the earth’s surface consists of minerals, dis¬
posed in horizontal strata, it was immediately
concluded, that the whole exterior crust of the
earth is composed, or has been composed, of
such strata, continued all round without inter¬
ruption ; and on this, as on a certain and gene¬
ral fact, entire theories of the earth have been
constructed.
There is no greater enemy which science has
to struggle with than this propensity of the
mind; and it is a struggle from which science is
never likely to be entirely relieved; because,
unfortunately, the illusion is founded on the
same principle from which our love of know¬
ledge takes its rise.
2. The Idols of the Den are those that spring
1 Novum Organum, lib. i. aph. 41.
572
PRELIMINARY DISSERTATIONS.
from the peculiar character of the individual.
Besides the causes of error which are common
to all mankind, each individual, according to
Bacon, has his own dark cavern or den, into
which the light is imperfectly admitted, and in
the obscurity of which a tutelary idol lurks, at
whose shrine the truth is often sacrificed.
One great and radical distinction in the capa¬
cities of men is derived from this, that some
minds are best adapted to mark the differences,
others to catch the resemblances, of things.
Steady and profound understandings are dis¬
posed to attend carefully, to proceed slowly,
and to examine the most minute differences;
while those that are sublime and active are
ready to lay hold of the slightest resemblances.
Each of these easily runs into excess; the one
by catching continually at distinctions, the other
at affinities.
The studies, also, to which a man is addicted,
have a great effect in influencing his opinions.
Bacon complains, that the chemists of his time,
from a few experiments with the furnace and
the crucible, thought that they were furnished
with principles sufficient to explain the struc¬
ture of the universe ; and he censures Aristotle
for having depraved his Physics so much with
his Dialectics, as to render the former entirely a
science of words and controversy. In like man¬
ner, he blames a philosopher of his own age,
Gilbert, who had studied magnetism to good
purpose, for having proceeded to form out of it
a general system of philosophy. Such things
have occurred in every period of science. Thus,
electricity has been applied to explain the mo¬
tion of the heavenly bodies ; and, of late, galva¬
nism and electricity together have been held out
as explaining not only the affinities of Chemistry,
but the phenomena of gravitation, and the laws
of vegetable and animal life. It were a good
caution for a man who studies nature, to distrust
those things with which he is particularly con¬
versant, and which he is accustomed to contem¬
plate with pleasure.
3. The Idols of the Forum are those that arise
out of the commerce or intercourse of society,
and especially from language, or the means by
which men communicate their thoughts to one
another.
Men believe that their thoughts govern their
words; but it also happens, by a certain kind
of reaction, that their words frequently govern
their thoughts. This is the more pernicious,
that words, being generally the work of the
multitude, divide things according to the lines
most conspicuous to vulgar apprehensions.
Hence, when words are examined, few instances
are found in which, if at all abstract, they con¬
vey ideas tolerably precise and well defined.
For such imperfections there seems to be no re¬
medy, but by having recourse to particular in¬
stances, and diligently comparing the meanings
of words with the external archetypes from
which they are derived.
4. The Idols of the Theatre are the last, and are
the deceptions which have taken their rise from
the systems or dogmas of the different schools
of philosophy. In the opinion of Bacon, as
many of these systems as had been invented, so
many representations of imaginary worlds had
been brought upon the stage. Hence the name
of idola theatri. They do not enter the mind
imperceptibly, like the other three; a man must
labour to acquire them, and they are often the
result of great learning and study.
“ Philosophy,” said he, “ as hitherto pursued,
has taken much from a few things, or a little
from a great many; and, in both cases, has too
narrow a basis to be of much duration or uti¬
lity.” The Aristotelian philosophy is of the latter
kind; it has taken its principles from common
experience, but without due attention to the
evidence or the precise nature of the facts; the
philosopher is left to work out the rest from his
own invention. Of this kind, called by Bacon
the sophistical, were almost all the physical sys¬
tems of antiquity.
When philosophy takes all its principles from
a few facts, he calls it empirical,—such as was
that of Gilbert, and of the chemists.
It should be observed, that Bacon does not
charge the Physics of antiquity with being ab¬
solutely regardless of experiment. No system,
indeed, however fantastical, has ever existed, to
which that reproach could be applied in its full
extent; because, without some regard to fact,
no theory can ever become in the least degree
plausible. The fault lies not, therefore, in the
DISSERTATION FOURTH.
573
absolute rejection of experience, but in the un¬
skilful use of it; in taking up principles lightly
from an inaccurate and careless observation of
many things; or, if the observations have been
more accurate, from those made on a few facts,
unwarrantably generalized.
Bacon proceeds to point out the circumstances,
in the history of the world, which had hitherto
favoured these perverse modes of philosophizing.
He observes, that the periods during which sci¬
ence had been cultivated were not many, nor of
long duration. They might be reduced to three;
the first with the Greeks; the second with the
Romans; and the third with the western na¬
tions, after the revival of letters. In none of
all these periods had much attention been paid
to Natural Philosophy, the great parent of the
sciences.
With the Greeks, the time was very short
during which physical science flourished in any
degree. The seven Sages, with the exception
of Thales, applied themselves entirely to morals
and politics; and in later times, after Socrates
had brought down philosophy from the heavens
to the earth, the study of nature was generally
abandoned. In the Roman republic, the know¬
ledge most cultivated, as might be expected
among a martial and ambitious people, was
such as had a direct reference to war and poli¬
tics. During the empire, the introduction and
establishment of the Christian religion drew the
attention of men to theological studies, and the
important interests which were then at stake
left but a small share of talent and ability to be
occupied in inferior pursuits. The vast hie¬
rarchy which assumed the command both of
the sword and the sceptre, while it occupied
and enslaved the minds of men, looked with
suspicion on sciences which could not easily be
subjected to its control.
At the time, therefore, when Bacon wrote, it
might truly be said, that a small portion even
of the learned ages, and of the abilities of learned
men, had been dedicated to the study of Natural
Philosophy. This served, in his opinion, to ac¬
count for the imperfect state in which he found
human knowledge in general; for he thought it
certain, that no part of knowledge could attain
much excellence without having its foundation
laid in physical science.
He goes on to observe, that the end and ob¬
ject of knowledge had been very generally mis¬
taken ; that many, instead of seeking through
it to improve the condition of human life, by
new inventions and new resources, had aimed
only at popular applause, and had satisfied them¬
selves with the knowledge of words more than
of things; while others, who were exceptions
to this rule, had gone still farther wrong, by di¬
recting their pursuits to objects imaginary and
unattainable. The alchemists, for example, al¬
ternately the dupes of their own credulity and
of their own imposture, had amazed and tor¬
mented the world with hopes which were never
to be realized. Others, if possible more vision¬
ary, had promised to prolong life, to extinguish
disease and infirmity, and to give man a com¬
mand over the world of spirits, by means of
mystic incantations. £< All this,” says he, “ is
the mere boasting of ignorance; for, when the
knowledge of nature shall be rightly pursued, it
will lead to discoveries that will as far excel the
pretended powers of magic, as the real exploits
of Caesar and Alexander exceed the fabulous
adventures of Arthur of Britain, or Amadis of
Gaul.”1
Again, the reverence for antiquity, and the
authority of great names, have contributed much
to retard the progress of science. Indeed, the
notion of antiquity which men have taken up
seems to be erroneous and inconsistent. It is
the duration of the world, or of the human race,
as reckoned from the extremity that is past, and
not from the point of time which is present, that
constitutes the true antiquity to which the ad¬
vancement of science may be conceived to bear
some proportion; and just as we expect more
wisdom and experience in an old than in a
young man, we may expect more knowledge of
nature from the present than from any of the
ages that are past.
u It is not to be esteemed a small matter
in this estimate, that, by the voyages and travels
of these later times, so much more of nature has
1 Novum Organum, lib. i. aph. 87-
574
PRELIMINARY DISSERTATIONS.
\
been discovered than was known at any former
period. It would, indeed, be disgraceful to
mankind, if, after such tracts of the material
world have been laid open, which were unknown
in former times,—so many seas traversed,—so
many countries explored,—so many stars dis¬
covered,—philosophy, or the intelligible world,
should be circumscribed by the same boundaries
as before.”
Another cause has greatly obstructed the pro¬
gress of philosophy, viz. that men inquire only
into the causes of rare, extraordinary, and great
phenomena, without troubling themselves about
the explanation of such as are common, and
make a part of the general course of nature.1
It is, however, certain, that no judgment can be
formed concerning the extraordinary and singu¬
lar phenomena of nature, without comparing
them with those that are ordinary and frequent.
The laws which are every day in action, are
those which it is most important for us to un¬
derstand; and this is well illustrated by what
has happened in the scientific world since the
time when Bacon wrote. The simple falling of
a stone to the ground has been found to involve
principles which are the basis of all we know in
mechanical philosophy. Without accurate ex¬
periments on the descent of bodies at the sur¬
face of the earth, the objections against the
earth’s motion could not have been answered,
the inertia of body would have remained un¬
known, and the nature of the force which re¬
tains the planets in their orbits could never
have been investigated. Nothing, therefore,
can be more out of its place than the fastidious¬
ness of those philosophers who suppose things
to be unworthy of study, because, with respect
to ordinary life, they are trivial and unimpor¬
tant. It is an error of the same sort which
leads men to consider experiment, and the ac¬
tual application of the hands, as unworthy of
them, and unbecoming the dignity of science.
<£ There are some,” says Bacon, “ who, delight¬
ing in mere contemplation, are offended with
our frequent reference to experiments and ope¬
rations to be performed by the hand, things
which appear to them mean and mechanical;
but these men do in fact oppose the attainment
of the object they profess to pursue, since the
exercise of contemplation, and the construction
and invention of experiments, are supported on
the same principles, and perfected by the same
means.”2
After these preliminary discussions, the great
restorer of philosophy proceeds, in the second
book of the Novum Organum, to describe and
exemplify the nature of the Induction, which he
deems essential to the right interpretation of
nature.
The first object must be to prepare a history
of the phenomena to be explained, in all their
modifications and varieties. This history is to
comprehend not only all such facts as sponta¬
neously offer themselves, but all the experiments
instituted for the sake of discovery, or for any
of the purposes of the useful arts. It ought
to be composed with great care; the facts accu¬
rately related, and distinctly arranged; their
authenticity diligently examined; those that rest
on doubtful evidence, though not rejected, being
noted as uncertain, with the grounds of the
judgment so formed. This last is very neces¬
sary ; for facts often appear incredible, only be¬
cause we are ill informed, and cease to appear
marvellous, when our knowledge is farther ex¬
tended.
All such facts, however, as appear contrary
to the ordinary course of our experience, though
thus noted down and preserved, must have no
weight allowed them in the first steps of inves¬
tigation, and are to be used only when the ge¬
neral principle, as it emerges from the inductive
process, serves to increase their probability.
This record of facts is what Bacon calls Natu¬
ral History; and it is material to take notice of
the comprehensive sense in which that term is
understood through all his writings. Accord¬
ing to the arrangement of the sciences, which
he has explained in his treatise on the Advance¬
ment of Knowledge, all learning is classed rela¬
tively to the three intellectual faculties of Me¬
mory, Reason, and Imagination. Under the
1 Novum Organum, lib. i. aph. 119.
2 Impetus Philosophici: Opera, p. C81, Franc, ad Moen. 1665, folio-
DISSERTATION FOURTH.
575
first of these divisions is contained all that is
merely Narration, or History, of whatever kind
it may be. Under the second are contained the
different sciences, whether they respect the In¬
tellectual or the Material world. Under the
third are comprehended Poetry and the Fine
Arts. It is with the first of these classes only
that we are at present concerned. The first two
divisions of it are Sacred and Civil History, the
meaning of which is sufficiently understood.
The third division is Natural History, which
comprehends the description of the facts rela-r
tive to inanimate matter, and to all animals, ex¬
cept man. Natural History is again subdivided
into three parts: 1. The history of the pheno¬
mena of nature, which are uniform; 2. Of the
facts which are anomalous or extraordinary;
3. Of the processes in the different arts.
We are not to wonder at finding the processes
of the arts thus enrolled among the materials of
Natural History. The powers which act in the
processes of nature and in those of art are pre¬
cisely the same, and are only directed, in the
latter case, by the intention of man, toward par¬
ticular objects. In art, as Bacon elsewhere ob¬
serves, man does nothing more than bring things
nearer to one another, or carry them farther
off; the rest is performed by nature, and, on
most occasions, by means of which we are quite
ignorant.
Thus, when a man fires a pistol, he does no¬
thing but make a piece of flint approach a plate
of hardened steel, with a certain velocity. It is
nature that does the rest;—that makes the small
red-hot and fluid globules of steel, which the flint
had struck off, communicate their fire to the
gunpowder, and, by a process but little under¬
stood, set loose the elastic fluid contained in it;
so that an explosion is produced, and the ball
propelled with astonishing velocity. It is obvi¬
ous that, in this instance, art only gives certain
powers of nature a particular direction.
To the rules which have been given from
Bacon, for the composition of Natural History, I
may be permitted to add this other,—that theo¬
retical language should, as much as possible, be
avoided. Appearances ought to be described in
terms which involve no' opinion with respect to
their causes. These last are the objects of sepa¬
rate examination, and will be best understood
if the facts are given fairly, without any depen¬
dence on what should yet be considered as un¬
known. This rule is very essential where the
facts are in a certain degree complicated; for it
is then much easier to describe with a reference
to theory than without it. It is only from a
skilful physician that you can expect a descrip¬
tion of a disease which is not full of opinions con¬
cerning its cause. A similar observation might
be made with respect to agriculture; and with
respect to no science more than geology.
The natural history of any phenomenon, or
class of phenomena, being thus prepared, the
next object is, by a comparison of the different
facts, to find out the cause of the phenomenon,
its foi’m, in the language of Bacon, or its essence.
The form of any quality in body is something
convertible with that quality; that is, where it
exists, the quality is present, and where the qua¬
lity is present, the form must be so likewise.
Thus, if transparency in bodies be the thing in¬
quired after, the form of it is something in which,
wherever it is found, there is transparency; and,
vice versa, wherever there is transparency, that
which we have called the form is likewise
present.
The form, then, differs in nothing from the
cause ; only we apply the word cause where it is
event or change that is the effect. When the
effect or result is a permanent quality, we speak
of the form or essence.
Two other objects, subordinate to forms, but
often essential to the knowledge of them, are also
occasionally subjects of investigation. These
are the latent process, and the latent schema¬
tism ; latens processus, et latens schematismus.
The former is the secret and invisible progress
by which sensible changes are brought about,
and seems, in Bacon’s acceptation, to involve the
principle, since called the law of continuity, ac¬
cording to which, no change, however small,
can be effected but in time. To know the rela¬
tion between the time and the change effected in
it, would be to have a perfect knowledge of the
latent process. In the firing of a cannon, for
example, the succession of events during the
short interval between the application of the
match and the expulsion of the ball, constitutes
576
PRELIMINARY DISSERTATIONS.
a latent process of a very remarkable and com¬
plicated nature, which, however, we can now
trace with some degree of accuracy. In mecha¬
nical operations, we can often follow this pro¬
cess still more completely. When motion is
communicated from any body to another, it is
distributed through all the parts of that pthef,
by a law quite beyond the reach of sense to per¬
ceive directly, hut yet subject to investigation,
and determined by a principle which, though late
in being discovered, is now generally recognised.
The applications of this mechanical principle are
perhaps the instances in which a latent, and, in¬
deed, a very recondite process, has been most
completely analyzed.
The latent schematism is that invisible struc¬
ture of bodies, on which so many of their proper¬
ties depend. When we inquire into the consti¬
tution of crystals, or into the internal structure
of plants, &c. we are examining into the latent
schematism. We do the same when we attempt
to explain elasticity, magnetism, gravitation, &c.
hy any peculiar structure of bodies, or any ar¬
rangement of the particles of matter.1 *
In order to inquire into the form or cause of
any thing hy induction, having brought together
the facts, we are to begin with considering what
things are thereby excluded from the number of
possible forms. This exclusion is the first part
of the process of induction: it confines the field
of hypothesis, and brings the true explanation
within narrower limits. Thus, if we were in¬
quiring into the quality which is the cause of
transparency in bodies; from the fact that the
diamond is transparent,we immediately exclude
rarity or porosity, as well as fluidity, from those
causes, the diamond being a very solid and dense
body.
Negative instances, or those where the given
form is wanting, are also to he collected.
That glass, when pounded, is not transparent,
is a negative fact, and of considerable importance
when iheform of transparency is inquired into;
also, that collections of vapour, such as clouds
and fogs, have not transparency, are negative
facts of the same kind. The facts thus collect¬
ed, both affirmative and negative, may, for the
sake of reference, he reduced into tables.
Bacon exemplifies his method on the subject
of Heat; and, though his collection of facts he
imperfect, his method of treating them is ex¬
tremely judicious, and the whole disquisition
highly interesting. - He here proposes, as an
experiment, to try the reflection of the heat of
opaque bodies.3 He mentions also the vitrum
'calendared or thermometer, which was just then
coming into use. His reflections, after finish¬
ing his enumeration of facts, show how sensible
he was of the imperfect state of his own know¬
ledge.4
After a great number of exclusions have left
but a few principles, common to every case,
one of these is to be assumed as the cause; and,
by reasoning from it synthetically, we are to
try if it will account for the phenomena.
So necessary did this exclusive process appear
to Bacon, that he says, “ It may perhaps be
competent to angels, or superior intelligences,
to determine the form or essence directly, by
affirmations from the first consideration of the
subject. But it is certainly beyond the power
of man, to whom it is only given to proceed at
first by negatives, and, in the last place, to end
in an affirmative, after the exclusion of every
thing else.”6
The method of induction, as laid down here,
is to be considered as applicable to all investiga¬
tions where experience is the guide, whether in
the moral or natural world. “ Some may doubt
whether we propose to apply our method of in¬
vestigation to natural philosophy only, or to
other sciences, such as logic, ethics, politics.
We answer, that we mean it to be so applied.
And as the common logic, which proceeds by the
syllogism, belongs not only to natural philoso¬
phy, but to all the sciences, so our logic, which
proceeds by induction, embraces every thing.’ 6
Though this process had been pursued by a
person of much inferior penetration and sagaci¬
ty to Bacon, he could not but have discovered
that all facts, even supposing them truly and
accurately recorded, are not of equal value in
1 Novum Orgunum, lib. ii. aph. 5, G, &c.
* Ibid. aph. 11.
* Ibid. lib. ii. aph. 15.
2 Ibid. aph. 18, 20, &c.
4 Ibid. aph. 14.
e Ibid. iib. i. aph. 127.
DISSERTATION FOURTH. 577
the discovery of truth. Some of them show the
thing sought for in its highest degree, some in
its lowest; some exhibit it simple and uncom¬
bined, in others it appears confused with a va¬
riety of circumstances. Some facts are easily
interpreted, others are very obscure, and are
understood only in consequence of the light
thrown on them by the former. This led our
author to consider what he calls Pr&rogativce
Instantiarmi, the comparative value of facts as
means of discovery, or as instruments of inves¬
tigation. He enumerates twenty-seven differ¬
ent species, and enters at some length into the
peculiar properties of each. I must content
myself, in this sketch, with describing a few of
the most important, subjoining, as illustrations,
sometimes the examples which the author him¬
self has given, hut more frequently such as have
been furnished by later discoveries in science.
I. The first place in this classification is as¬
signed to what are called instantim solitaries,
which are either examples of the same quality
existing in two bodies which have nothing in
common but that quality, or of a quality differ¬
ing in two bodies which are in all other respects
the same. In the first instance, the bodies dif¬
fer in all things but one; in the second, they
agree in all but one. The hypotheses that in
either case can be entertained, concerning the
cause or form of the said quality, are reduced to
a small number; for, in the first, they can in¬
volve none of the things in which the bodies
differ; and, in the second, none of those in
which they agree.
Thus, of the cause or form of colour now in¬
quired into, instantice solitaries are found in crys¬
tals, prisms of glass, drops of dew, which occa¬
sionally exhibit colour, and yet have nothing in
common with the stones, flowers, and metals,
which possess colour permanently, except the
colour itself. Hence Bacon concludes, that co¬
lour is nothing else than a modification of the
rays of light, produced, in the first case, by the
different degrees of incidence; and, in the se¬
cond, by the texture or constitution of the sur¬
faces of bodies. He may be considered as very
lortunate in fixing on these examples ; for it was
by means of them that Newton afterwards found
out the composition of light.
Of the second kind of instanties solitaries. Ba¬
con mentions the white or coloured veins which
occur in limestone or marble, and yet hardly
differ in substance or in structure from the
ground of the stone. He concludes, very just¬
ly, from this, that colour has not much to do
with the essential properties of body.
II. The instanties migrantes exhibit some nature
or property of body, passing from one condition
to another, either from less to greater, or from
greater to less; arriving nearer perfection in the
first case, or verging towards extinction in the
second.
Suppose the thing inquired into were the
cause of whiteness in bodies; an instantia mi-
grans is found in glass, which, when entire, is
without colour, but, when pulverized, becomes
white. The same is the case with water un¬
broken, and water dashed into foam. In both
cases, the separation into particles produces
whiteness. So also the communication of flu¬
idity to metals by the application of heat, and
the destruction of that fluidity by the abstrac¬
tion of heat, are examples of both kinds of the
instantia migrans. Instances of this kind are
very powerful for reducing the cause inquired
after into a narrow space, and for removing
all the accidental circumstances. It is neces¬
sary, however, as Bacon very justly remarks,1
that we should consider not merely the case
when a certain quality is lost, and another pro¬
duced, but the gradual changes made in those
qualities during their migration, viz. the in¬
crease of the one, and the corresponding diminu¬
tion of the other. The quantity which changes
proportionally to another, is connected with it
either as cause and effect, or as a collateral ef¬
fect of the same cause. When, again, we find
two qualities which do not increase proportion-
ally, they afford a negative instance, and assure
us that the two are not connected simply as
cause and effect.
The mineral kingdom is the great theatre of
the instanties migrantes, where the same nature is
seen in all gradations, from the most perfect
4 D
DISS. IV., PART I.
1 Novum Organum, lib. ii. aph. 23.
578
PRELIMINARY DISSERTATIONS.
state, till it become entirely evanescent. Such
are the shells which we see so perfect in figure
and structure in limestone, and gradually losing
themselves in the finer marbles, till they can no
longer be distinguished. The use, also, of one
such fact to explain or interpret another, is no¬
where so well seen as in the history of the mi¬
neral kingdom.
III. In the third place are the instantice osten-
sivcb, which Bacon also calls elucescentice and
pradoininantes. They are the facts which show
some particular nature in its highest state of
power and energy, when it is either freed from the
impediments which usually counteract it, or is
itself of such force as entirely to repress those
impediments. For as every body is susceptible
of many different conditions, and has many dif¬
ferent forms combined in it, one of them often
confines, depresses, and hides another entirely,
so that it is not easily distinguished. There
are found, however, some subjects in which the
nature inquired into is completely displayed,
either by the absence of impediments, or by the
predominance of its own power.
Bacon instances the thermometer, or vitrum
calendared as exhibiting the expansive power of
heat, in a manner more distinct and measurable
than in common cases. To this example, which
is well chosen, the present state of science en¬
ables us to add many others.
If the weight of the air were inquired into,
the Torricellian experiment, or the barometer,
affords an ostensive instance, where the circum¬
stance which conceals the weight of the atmo¬
sphere in common cases, namely, the pressure of
it in all directions, being entirely removed, that
weight produces its full effect, and sustains the
whole column of mercury in the tube. The ba¬
rometer affords also an example of the instantia
migrans, when the change is not total, but only
partial or progressive. If it be the weight of
the air which supports the mercury in the tube
of the barometer, when that weight is diminish¬
ed, the mercury ought to stand lower. On go¬
ing to the top of a mountain, the weight of the
incumbent air is diminished, because a shorter
column of air is to be sustained; the mercury
in the barometer ought therefore to sink, and it
is found to do so accordingly.
These are instances in which the action of
certain principles is rendered visible by the re¬
moval of all the opposing forces. One may be
given where it is the distinct and decisive nature
of the fact which leads to the result.
Suppose it were inquired, whether the present
land had ever been covered by the sea. If we
look at the stratified form of so large a portion
of the earth’s surface, we cannot but conclude
it to be very probable that such land was form¬
ed at the bottom of the sea. But the decisive
proof is afforded by the shells and corals, or bo¬
dies having the perfect shape of shells and co¬
rals, and of other marine exuviae, which are
found imbedded in masses of the most solid
rock, and often on the tops of very high moun¬
tains. This leaves no doubt of the formation of
the land under the sea, though it does not de¬
termine whether the land, since its formation,
has been elevated to its present height, or the
sea depressed to its present level. The decision
of that question requires other facts to be con¬
sulted.
IV. The instantia clandestina, which is, as it
were, opposed to the preceding, and shows some
power or quality just as it is beginning to exist,
and in its weakest state, is often very useful in
the generalization of facts. Bacon also gave to
this the fanciful name of instantia crepusculi.
An example of this may be given from hy¬
drostatics. If the suspension of water in ca¬
pillary tubes be inquired into, it becomes very
useful to view that effect when it is least, or
when the tube ceases to be capillary, and be¬
comes a vessel of a large diameter. The column
is then reduced to a slender ring of water, which
goes all round the vessel; and this, though now
so inconsiderable, has the property of being in¬
dependent of the size of the vessel, so as to be
in all cases the same when the materials are the
same. As there can be no doubt that this ring
proceeds from the attraction of the sides, and of
the part immediately above the water, so there
can be no doubt that the capillary suspension,
in part at least, is derived from the same cause.
An effect of the opposite kind takes place when
a glass vessel is filled with mercury.
V. Next to these may be placed what are call¬
ed instantice manipulares, or collective instances,
DISSERTATION FOURTH.
579
that is, general facts, or such as comprehend a
great number of particular cases. As human
knowledge can but seldom reach the most gene¬
ral cause or form, such collective instances are
often the utmost extent to which our generali¬
zation can be carried. They have great value
on this account, as they likewise have on ac¬
count of the assistance which they give to fur¬
ther generalization.
Of this we have a remarkable instance in one
of the most important steps ever taken in any
part of human knowledge. The laws of Kepler
are facts of the kind now treated of, and consist
of three general truths, each belonging to the
whole planetary system; and it was by means
of them that Newton discovered the principle of
gravitation. The first is, that the planets all
move in elliptical orbits, having the sun for their
common focus; the next, that about this focus
the radius vector of each planet describes equal
areas in equal times; the third and last, that
the squares of the periodic times of the planets
are as the cubes of their mean distances from
the sun. The knowledge of each of these was
the result of much research, and of the compa¬
rison of a vast multitude of observations, inso¬
much that it may be doubted if ever three truths
in science were discovered at the expense of so
much labour and patience, or with the exertion
of more ingenuity and invention in imagining
and combining observations. These discoveries
were all made before Bacon wrote, but he is
silent concerning them ; for the want of mathe¬
matical knowledge concealed from his view some
of the most splendid and interesting parts of
science.
Astronomy is full of such collective instances,
and affords them, indeed, of the second and
third order, that is to say, two or three times
generalized. The astronomer observes nothing
but that a certain luminous disk, or perhaps
merely a luminous point, is in a certain position,
in respect of the planes of the meridian and the
horizon, at a certain moment of time. By com¬
paring a number of such observations, he finds
that this luminous point moves in a certain plane,
with a certain velocity, and performs a revolu¬
tion in a certain time. Thus, the periodic time
of a planet is itself a collective fact, or a single
fact expressing the result of many hundred ob¬
servations. This holds with respect to each
planet, and with respect to each element, as it is
called, of the planet’s orbit, every one of which
is a general fact, expressing the result of an in¬
definite number of particulars. This holds still
more remarkably of the inferences which extend
to the distances of the planet from the earth, or
from the sun. The laws of Kepler are therefore
collective facts of the second, or even a higher
order; or such as comprehend a great number of
general facts, each of which is itself a general
fact, including many particulars. It is much to
the credit of astronomy, that, in all this process,
no degree of truth or certainty is sacrificed; and
that the same demonstrative evidence is preserv¬
ed from the lowest to the highest point. No¬
thing but the use of mathematical reasoning
could secure this advantage to any of the sciences.
VI. In the next place may be ranked the in¬
stances which Bacon calls analogous, or parallel.
These consist of facts, between which an ana¬
logy or resemblance is visible in some particu¬
lars, notwithstanding great diversity in all the
rest. Such are the telescope and microscope, in
the works of art, compared with the eye in the
works of nature. This, indeed, is an analogy
which goes much beyond the mere exterior; it
extends to the internal structure, and to the
principle of action, which is the same in the eye
and in the telescope,—to the latent schematism,
in the language of Bacon, as far as material
substance is concerned. It was the experiment
of the camera ohscura which led to the discovery
of the formation of the images of external ob¬
jects in the bottom of the eye by the action of
the crystalline lens, and the other humours of
which the eye is formed.
Among the instances of conformity, those are
the most useful which enable us to compare pro*
ductions of an unknown formation, with similar
productions of which the formation is wrell under¬
stood. Such are basalt, and the other trap rocks,
compared with the lava thrown out from volca¬
noes. They have a structure so exactly similar,
that it is hardly possible to doubt that their ori¬
gin is the same, and that they are both produced
by the action of subterraneous fire. There are,
however, amid their similarity, some very re-
580
PRELIMINARY DISSERTATIONS.
markable differences in the substances which
they contain, the trap rocks containing calcare¬
ous spar, and the lava never containing any.
On the supposition that they are both of igneous
origin, is there any circumstance, in the condi¬
tions in which heat may have been applied to
them, which can account for this difference ?
Sir James Hall, in a train of most philosophical
and happily-contrived experiments, has explain¬
ed the nature of those conditions, and has shown
that the presence of calcareous spar, or the want
of it, may arise from the greater or less com¬
pression under which the fusion of the basalt
was performed. This has served to explain a
great difficulty in the history of the mineral
kingdom.
Comparative anatomy is full of analogies of
this kind, which are most instructive, and use¬
ful guides to discovery. It was by remarking
in the blood-vessels a contrivance similar to the
valves used in hydraulic engines, for preventing
the counter-current of a fluid, that Harvey was
led to the discovery of the circulation of the
blood. The analogies between natural and arti¬
ficial productions arc always highly deserving of
notice.
The facts of this class, however, unless the
analogy be very close, are apt to mislead, by re¬
presenting accidental regularity as if it were
constant. Of this we have an example in the
supposed analogy between the colours in the
prismatic spectrum and the divisions of the mo¬
nochord. The colours in the prismatic spectrum
do not occupy the same proportion of it in all
cases; the analogy depends on the particular kind
of glass, not on any thing that is common to all
refraction. The tendency of man to find more
order in things than there actually exists, is here
to be cautiously watched over.
VII. Monodic, or singular facts, are the next in
order. They comprehend the instances which are
particularly distinguished from all those of the
genus or species to which they belong. Such is
the sun among the stars, the magnet among stones,
mercury among metals, boiling fountains among
springs, the elephant among quadrupeds. So
also among the planets, Saturn is singular from
his ring; the new planets are so likewise from their
small size, from being extrazodiacal, &c.
Connected with these are the irregular and
deviating instances, in which nature seems to
depart from her ordinary course. Earthquakes,
extraordinary tempests, years of great scarcity,
winters of singular severity, &c. are of this num¬
ber. All such facts ought to be carefully col¬
lected ; and there should be added an account of
all monstrous productions, and of every thing re¬
markable for its novelty and its rareness. Here,
however, the most severe criticism must be ap¬
plied ; every thing connected with superstition is
suspicious, as well as whatever relates to alche¬
my or magic.
A set of facts, which belongs to this class,
consists of the instances in which stones have so
often of late years been observed to fall from the
heavens. Those stones are so unlike other at¬
mospherical productions, and their origin must
be so different from that of other minerals, that
it is scarcely possible to imagine any thing more
anomalous, and more inconsistent with the ordi¬
nary course of our experience. Yet the exist¬
ence of this phenomenon is so well authenticat¬
ed by testimony, and by the evidence arising
from certain physical considerations, that no
doubt with respect to it can be entertained, and
it must therefore be received, as making a part
of the natural history of meteors. But as every
fact, or class of facts, which is perfectly singu¬
lar, must be incapable of explanation, and can
only be understood when its resemblance to
other things has been discovered; so at present
we are unable to assign the cause of these pheno¬
mena, and have no right to offer any theory of
their origin.
VIII. Another class of facts is composed of
what Bacon calls instantice comitatus, or examples
of certain qualities which always accompany one
another. Such are flame and heat,—flame being
always accompanied by heat, and the same de¬
gree of heat in a given substance being always
accompanied with flame. So also heat and ex¬
pansion,—an increase of heat being accompanied
with an increase of volume, except in a very
few cases, and in circumstances very particular.
The most perfect instantia comitatus known,
as being without any negative, is that of body
and weight. Whatever is impenetrable and
inert, is also heavy in a degree proportional to
DISSERTATION FOURTH.
581
its inertia. To tins there is no exception, though
we do not perceive the connection as necessary.
Hostile instances, or those of perpetual sepa¬
ration, are the reverse of the former.
Examples of this are found in air, and the
other elastic fluids, which cannot have a solid
form induced on them by any known means,
when not combined with other substances. So
also in solids, transparency and malleability are
never jollied, and appear to be incompatible,
though it is not obvious for what reason.
IX. Passing over several classes which seem
of inferior importance, we come to the instantia
crucis, the division of this experimental logic
which is most frequently resorted to in the
practice of inductive investigation. When, in
such an investigation, the understanding is
placed in equilibrio, as it were, between two or
more causes, each of which accounts equally
well for the appearances, as far as they are
known, nothing remains to be done but to look
out for a fact which can be explained by the
one of these causes, and not by the other: if
such a one can be found, the uncertainty is re¬
moved, and the true cause is determined. Such
facts perform the office of a cross, erected at
the separation of two roads, to direct the tra->
veller which he is to take; and, on this account,
Bacon gave them the name of instantice crucis.
Suppose that the subject inquired into were
the motion of the planets, and that the pheno¬
mena which first present themselves, or the
motion of these bodies in longitude, could be ex^
plained equally on the Ptolemaic and the Coper-
nican system, that is, either on the system which
makes the earth, or that which makes the sun,
the centre of the planetary motions; a cautious
philosopher would hesitate about which of the
two he should adopt, and notwithstanding that
one of them was recommended by its superior
simplicity, he might not think himself autho¬
rized to give to it a decided preference above
the other. If, however, he consider the motion
of these bodies in latitude, that is to say, their
digressions from the plane of the ecliptic, he
will find a set of phenomena which cannot be
reconciled with the supposition that the earth
is the centre of the planetary motions, but which
receive the most simple and satisfactory expla¬
nation from supposing that the sun is at rest,
and is the centre of those motions. The latter
phenomena would therefore serve as instanticc
crucis, by which the superior credibility of the
Copernican system was fully evinced.
Another example which I shall give of an
instantia crucis is taken from Chemistry, and is,
indeed, one of the most remarkable experiments
which has been made in that science.
It is a general fact observed in Chemistry, that
metals are always rendered heavier by calcina¬
tion. When a mass of tin or lead, for instance,
is calcined in the fire, though every precaution
is taken to prevent any addition from the adhe¬
sion of ashes, coals, &c. the absolute weight of
the mass is always found to be increased. It
was long before the cause of this phenomenon
was understood. There might be some heavy
substance added, though what it was could not
easily be imagined; or some substance might
have escaped, which was in its nature light,
and possessed a tendency upwards. Other phe¬
nomena, into the nature of which it is at pre¬
sent unnecessary to inquire, induced chemists
to suppose, that in calcination a certain sub¬
stance actually escapes, being present in the
regulus, but not in the calx of the metal. This
substance, to which they gave the name of
phlogiston, was probably that which, by its
escape, rendered the metal heavier, and must,
therefore, be itself endued with absolute levity.
The instantia crucis which extricated philoso¬
phers from this difficulty, was furnished by an
experiment of the celebrated Lavoisier. That
excellent chemist included a quantity of tin in
a glass retort, hermetically sealed, and accurate¬
ly weighed together with its contents; he then
applied the necessary heat, and when the cal¬
cination of the tin was finished, he found the
weight of the whole precisely the same as before.
This proved that no substance, which was either
light or heavy, in a sensible degree, had made
its way through the glass. The experiment
went still farther. When the retort was cooled
and opened, the air rushed in; so that it was
evident that a part of the air had disappeared,
or had lost its elasticity. On weighing the
whole apparatus, it was now found that its
weight was increased by ten grains; so that ten
582
PRELIMINARY DISSERTATIONS.
grains of air had entered into the retort when
it was opened. The calx was next taken out,
and weighed separately, and it was found to
have become heavier by ten grains precisely.
The ten grains of air then which had disap¬
peared, and which had made way for the ten
grains that rushed into the retort, had combined
with the metal during the process of calcination.
The further prosecution of this very decisive ex¬
periment led to the knowledge of that species of
air which combines with metals when they are
calcined. The doctrine of phlogiston was of
course exploded, and a creature of the imagina¬
tion replaced by a real existence.
The principle which conducts to the contriv¬
ance of an experimentum crucis is not difficult to
be understood. Taking either of the hypotheses,
its consequences must he attempted to he traced,
supposing a different experiment to he made.
This must be done with respect to the other
hypothesis, and a case will probably at last oc¬
cur, where the two hypotheses would give dif¬
ferent results. The experiment made in those
circumstances will furnish an instantia crucis.
Thus, if the experiment of calcination he per¬
formed in a close vessel, and if phlogiston be the
cause of the increase of weight, it must either
escape through the vessel, or it must remain in
the vessel after separation from the calx. If the
former he the case, the apparatus will be in¬
creased in weight; if the latter, the phlogiston
must make its escape on opening the vessel. If
neither of these be the case, it is plain that the
theory of phlogiston is insufficient to explain the
facts.
The experimentum crucis is of such weight in
matters of induction, that in all those branches
of science where it cannot easily be resorted to,
(the circumstances of an experiment being out
of our power, and incapable of being varied at
pleasure) there is often a great want of con¬
clusive evidence. This holds of agriculture,
medicine, political economy, &c. To make one
experiment, similar to another in all respects
but one, is what the experimentum crucis, and, in
general, the process of induction, principally re¬
quires; but it is what, in the sciences just
named, can seldom be accomplished. Hence the
great difficulty of separating the causes, and al¬
lotting to each its due proportion of the effect.
Men deceive themselves in consequence of this
continually, and think they are reasoning from
fact and experience, when, in reality, they are
only reasoning from a mixture of truth and
falsehood. The only end answered by facts so
incorrectly apprehended, is that of making er¬
ror more incorrigible.
Of the twenty-seven classes into which in-
stantice are arranged by the author of the Novum
Organum, fifteen immediately address themselves
to the Understanding; five serve to correct or
to inform the Senses; and seven to direct the
hand in raising the superstructure of Art on the
foundation of Science. The examples given
above are from the first of these divisions, and
will suffice for a summary. To the five that
follow next, the general name of instantice lam-
padis is given, from their office of assisting or
informing the senses.
Of these the instantice januce assist the imme¬
diate action of the senses, and especially of sight.
The examples quoted by Bacon are the micro¬
scope and telescope, (which last he mentions as
the invention of Galileo) and he speaks of them
with great admiration, but with some doubt of
their reality.
The instantice citantes enable us to perceive
things which are in themselves insensible, or not
at all the objects of perception. They cite or
place things, as it were, before the bar of the
senses, and from this analogy to judicial pro¬
ceedings is derived the name of instantice citantes.
Such, to employ examples which the progress of
science has unfolded^since the'time of Bacon,
are the air-pump and the barometer for mani¬
festing the weight and elasticity of air; the
measurement of the velocity of light, by means
of the eclipses of the satellites of Jupiter, and
the aberration of the fixed stars; the experi¬
ments in electricity and galvanism, and in the
greater part of pneumatic chemistry. In all
these instances things are made known which
before had entirely escaped the senses.
The instantice vice are facts which manifest the
continuous progress of nature in her operations.
There is a propensity in men to view nature as
it were at intervals, or at the ends of fixed pe¬
riods, without regarding her gradual and un-
DISSERTATION FOURTH.
583
ceasing action.1 The desire of making obser¬
vation easy is the great source of this propensity.
Men wish for knowledge, but would obtain it at
the least expense of time and labour. As there
is no time, however, at which the hand of nature
ceases to work, there ought to be none at which
observation ceases to be made.
The instantia persecantes, or vellicantes, are
those which force us to attend to things which,
from their subtilty and minuteness, escape com¬
mon observation.
Some of Bacon’s remarks on this subtilty are
such as would do credit to the most advanced
state of science, and show how much his mind
was fitted for distinguishing and observing the
great and admirable in the works of nature.
The last division contains seven classes, of
which I mention only two. The experiments
of this division are those most immediately tend¬
ing to produce the improvement of art from the
extension of science. c< Now there are,” says
Bacon, “ two ways in which knowledge, even
when sound in itself, may fail of becoming a safe
guide to the artist; and these are either when it
is not sufficiently precise, or when it leads to
more complicated means of producing an effect
than can be employed in practice. There are
therefore two kinds of experiments which are
of great value in promoting the alliance between
knowledge and power;—those which tend to give
accurate and exact measures of objects, and
those which disencumber the processes deduced
from scientific principles, of all unnecessary ope¬
rations.”
In the instantia radii we measure objects by
lines and angles; in the instantm curriculi, by
time or by motion.
To the former of these classes are to be re¬
ferred a number of instruments which now con¬
stitute the greater part of the apparatus of Na¬
tural Philosophy. Though Bacon had a just
idea of their utility in general, he was unac¬
quainted with most of them. The most remark¬
able at present are those that follow..
1. Astronomical instruments, or, more gene-
rally, all instruments for measuring lines and
angles.
2. Instruments for measuring weight or force;
such are the common balance, the hydrostatic
balance, the barometer, the instruments used in
England by Cavendish, and in France by Cou¬
lomb, which measure small and almost insensi¬
ble actions by the force of torsion.
These last rather belong to the class of the
instantice luctce, where force is applied as the
measure of force, than to the instantice radii.
3. The thermometer, newly invented in the
time of Bacon, and mentioned by him under
the name ot Vitrum Calendared an instrument to
which we owe nearly all the knowledge we have
of one of the most powerful agents in nature,
viz. Heat.
4. The hygrometer, an instrument for mea¬
suring the quantity of humidity contained in the
air; and in the construction of which, after re¬
peated failures by the most skilful experimenters,
the invention of Professor Leslie now promises
success. Almost every one of these instruments,
to which several more might be added, has
brought in sight a new country, and has enriched
science not only with new facts, but with new
principles.
Among the remarks of Bacon on the experi-
menta radii, some are very remarkable for the
extent of view which they display even in the in¬
fancy of physical science. He mentions the
forces by which bodies act on one another at a
distance, and throws out some hints at the at¬
traction which the heavenly bodies exert on one
another.
“ Inquirendum est,” says he,^ si sit vis aliqua
magnetica quse operetur per consensum inter
globum terrse et ponderosa, aut inter globum
lunse et aquas maris, aut inter coelum stellatum
et planetas, per quam avocentur et attollantur ad
sua apogaea; haec omnia operantur ad distantias
admodum longinquas.”2
Under the head of the instantia curriculi, or
the measuring of things by time; after remark¬
ing that every change and every motion requires
time, and illustrating this by a variety of in¬
stances, he has the following very curious anti¬
cipation of facts, which appeared then doubtful,
but which subsequent discovery has ascertained:
1 Novum Organum, lib. ii. aph. 41.
2 Ibid. aph. 45.
PRELIMINARY DISSERTATIONS.
534
<c The consideration of those things produced
in me a doubt altogether astonishing, viz. M he-
ther the face of the serene and starry heavens be
seen at the instant it really exists, or not till some
time later ; and whether there be not, with re¬
spect to the heavenly bodies, a true time and an
apparent time, no less than a true place and an
apparent place, as astronomers say, on account
of parallax. For it seems incredible that the
species or rays of the celestial bodies can pass
through the immense interval between them
and us in an instant, or that they do not even
require some considerable portion of time.”1
The measurement of the velocity of light, and
the wonderful consequences arising from it, are
the best commentaries on this passage, and the
highest eulogy on its author.
Such were the speculations of Bacon, and the
rules he laid down for the conduct of experi¬
mental inquiries, before any such inquiries had
yet been instituted. The power and compass of
a mind which could form such a plan beforehand,
and trace not merely the outline, but many of
the most minute ramifications, of sciences which
did not yet exist, must be an object of admiration
to all succeeding ages. He is destined, if in¬
deed any thing in the world be so destined, to
remain an instantia singularis among men, and
as he has had no rival in the times which are
past, so is he likely to have none in those which
are to come. Before any parallel to him can be
found, not only must a man of the same talents
be produced, but he must be placed in the same
circumstances; the memory of his predecessor
must be effaced, and the light of science, after
being entirely extinguished, must be again be¬
ginning to revive. If a second Bacon is ever to
arise, he must be ignorant of the first.
Bacon is often compared with two great men
who lived nearly about the same time with him¬
self, and who were both eminent reformers of
philosophy, Descartes and Galileo.
Descartes flourished about forty years later
than Bacon, but does not seem to have been ac¬
quainted with his writings. Like him, however,
he was forcibly struck with the defects of the
ancient philosophy, and the total inaptitude of
the methods which it followed, for all the pur¬
poses of physical investigation. Like him, too,
lie felt himself strongly impelled to undertake
the reformation of this erroneous system; but
the resemblance between them goes no farther;
for it is impossible that two men could pursue
the same end by methods more diametrically
opposite.
Descartes never proposed to himself any thing
which had the least resemblance to induction.
He began with establishing principles, and from
the existence of the Deity and his perfections,
he proposed to deduce the explanation of all the
phenomena of the world, by reasoning a priori.
Instead of proceeding upward from the effect to
the cause, he proceeded continually downward
from the cause to the effect. It was in this man¬
ner that he sought to determine the laws of mo¬
tion, and of the collision of bodies, in which last
all his conclusions were erroneous. From the
same source he deduced the existence of a ple¬
num^ and the continual preservation of the same
quantity of motion in the universe; a proposi¬
tion which, in a certain sense, is true, but in the
sense in which he understood it, is altogether
false. Reasonings of the kind which he em¬
ployed may possibly suit, as Bacon observed,
with intelligences of a higher order than man,
but to his case they are quite inapplicable. Of
the fruit of this tree nature has forbidden him
to eat, and has ordained that, with the sweat of
his brow, and the labour of his hands, he should
earn his knowledge as well as his subsistence.
Descartes, however, did not reject experiment
altogether, though he assigned it a very subor¬
dinate place in his philosophy. By reasoning
down from first principles, he tells us that he
was always able to discover the effects; but the
number of different shapes which those effects
might assume was so great, that he could not
determine, without having recourse to experi¬
ment, which of them nature had preferred to the
rest. “ We employ experiment,” says he, “ not
as a reason by which any thing is proved, for
we wish to deduce effects from their causes, and
not conversely causes from their effects. We
1 Novum Orgatiutn, lib. ii. aph. 4G.
DISSERTATION EOUIiTH.
585
appeal to experience only, that out of innume¬
rable effects which may be produced from the
same cause, we may direct our attention to one
rather than another.” It is wonderful, that
Descartes did not see what a Severe censure he
was here passing on himself ; of how little value
the speculations must be that led to conclusions
so vague and indefinite; and how much more
philosophy is disgraced by affording an explana¬
tion of things which are not, than by not afford¬
ing an explanation of things which are.
As a system of philosophy and philosophic
investigation, the method of Descartes can,
therefore, stand in no comparison with that of
Bacon. Yet his Physics contributed to the ad¬
vancement of science, but did so, much more hy
that which they demolished, than by that which
they built up. In some particular branches the
French philosopher far excelled the English.
He greatly improved the science of optics, and
in the pure mathematics, as has been already
shown, he left behind him many marks of a
great and original genius. He will, therefore,
be always numbered among those who have
essentially contributed to the advancement of
knowledge, though nothing could be more per¬
verse than his method of philosophizing, and
nothing more likely to impede the progress of
science, had not an impulse been at that time
given to the human mind which nothing could
resist.
Galileo, the other rival and contemporary of
Bacon, is, in truth, one of those to whom hu¬
man knowledge is under the greatest obligations.
His discoveries in the theory of motion, in the
laws of the descent of heavy bodies, and in the
motion of projectiles, laid the foundation of all the
great improvements which have since been made
by the application of Mathematics to Natural
Philosophy. If to this we add the invention of
the telescppe, the discoveries made by that in¬
strument, the confirmations of the Copernican
system which these discoveries afforded, and,
lastly, the wit and argument with which he
combated and exposed the prejudice and pre¬
sumption of the schools, we must admit that the
history of human knowledge contains few greater
names than that of Galileo. On comparing him
with Bacon, however, I have no hesitation in
saying, that the latter has given indications of a
genius of a still higher order. In this I know
that I differ from a historian who was himself
a philosopher, and whose suffrage, of conse¬
quence, is here of more than ordinary weight.
“ The great glory of literature,” says Hume,
“ in this island, during the reign of James, was
Lord Bacon. If we consider the variety of ta¬
lents displayed by this man, as a public speaker,
a man of business, a wit, a courtier, a compan¬
ion, an author, a philosopher, he is justly en¬
titled to great admiration. If we consider him
merely as an author and a philosopher, the light
in which we view him at present, though very
estimable, he was yet inferior to his contempo¬
rary Galileo, perhaps even to Kepler. Bacon
pointed out, at a distance, the road to philoso¬
phy; Galileo both pointed it out to others, and
made himself considerable advances in it. The
Englishman was ignorant of geometry; the
Florentine revived that science, excelled in it,
and was the first who applied it, together with
experiment, to natural philosophy. The former
rejected, with the most positive disdain, the
system of Copernicus; the latter fortified it
with new proofs, derived both from reason and
the senses. Bacon’s style is stiff and rigid; his
wit, though often brilliant, is also often unnatu¬
ral and far-fetched. Galileo is a lively and
agreeable, though somewhat a prolix writer.”1
Though it cannot be denied that there is con¬
siderable truth in these remarks, yet it seems to
me that the comparison is not made with the
justness and discrimination which might have
been expected from Hume, who appears studi¬
ously to have contrasted what is most excellent
in Galileo with what is most defective in Bacon.
It is true that Galileo showed the way in the
application of mathematics and of geometry to
physical investigation, and that the immediate
utility of his performance was greater than that
of Bacon’s, as it impressed more movement on
the age in which he lived, example being always
so much more powerful than precept. Bacon,
indeed, wrote for an age more enlightened than
4 E
DISS. IV., PART I.
1 History of England, vol. VI. Appendix.
586
PRELIMINARY DISSERTATIONS.
his own, and it was long before the full merit
of his work was understood. But though Gali¬
leo was a geometer, and Bacon unacquainted
with the mathematics,—though Galileo added
new proofs to the system of the earth’s motion,
which Bacon rejected altogether,—yet is it cer¬
tain, I think, that the former has more fellows
or equals in the world of science than the latter,
and that his excellence, though so high, is less
unrivalled. The range which Bacon’s specula¬
tions embraced was altogether immense. He
cast a penetrating eye on the whole of science,
from its feeblest and most infantine state, to that
strength and perfection from which it was then
so remote, and which it is perhaps destined to
approach to continually, hut never to attain.
More substitutes might be found for Galileo than
for Bacon. More than one could he mentioned,
who, in the place of the former, would probably
have done what he did; hut the history of hu¬
man knowledge points out nobody of whom it
can he said, that, placed in the situation of
Bacon, he would have done what Bacon did;—
no man whose prophetic genius would have
enabled him to delineate a system of science
which had not yet begun to exist—-who could
have derived the knowledge of what ought to he
from what was not, and who could have become
so rich in wisdom, though he received from his
predecessors no inheritance but their errors. I
am inclined, therefore, to agree with D’Alem¬
bert, “ that when one considers the sound and
enlarged views of this great man, the multitude
of the objects to which his mind was turned,
and the boldness of his style, which unites the
most sublime images with the most rigorous
precision, one is disposed to regard him as the
greatest, the most universal, and the most elo¬
quent of philosophers.”1 2
3. REMARKS, &C.
It will hardly be doubted by any one who at¬
tentively considers the method explained in the
Novum Organum, which we have now attempted
to sketch, that it contains a most comprehensive
and rigorous plan of inductive investigation. A
question, however, may occur, How far has this
method been really carried into practice by those
who have made the great discoveries in Natural
Philosophy, and who have raised physical science
to its present height in the scale of human know¬
ledge ? Is the whole method necessary, or have
not circumstances occurred, which have render¬
ed experimental investigation easier in practice
than it appears to be in theory? To answer
these questions completely, would require more
discussion than is consistent with the limits of
this Dissertation : I shall, therefore, attempt no
more than to point out the principles on which
such an answer may be founded.
In a very extensive department of physical
science, it cannot be doubted that investigation
has been carried on, not perhaps more easily,
but with a less frequent appeal to experience,
than the rules of the Novum Organum would
seem to require. In all the physical inquiries
where mathematical reasoning has been employ¬
ed, after a few principles have been established
by experience, a vast multitude of truths, equally
certain with the principles themselves, have been
deduced from them by the mere application of
geometry and algebra.
In mechanics, for example, after the laws of
motion were discovered, which was done by ex¬
periment, the rest of the science, to a great ex¬
tent, was carried on by reasoning from those
laws, in the same manner that the geometer
makes his discoveries by reasoning on the defi¬
nitions, by help of a few axioms, or self-evident
propositions. The only difference is, that, in the
one case, the definitions and axioms are supplied
solely from the mind itself, Avhile, in the other,
all the definitions and axioms which are not
those of pure geometry, are furnished by ex¬
perience. c
Bacon certainly was not fully aware of the
advantages that were thus to accrue to the phy¬
sical sciences. He was not ignorant, that the
introduction of mathematical reasoning into
those sciences is not only possible, but that, un-
1 Discours Preliminaire de I’Encyclopddie.
2 The part of Mechanics which involves only statical considerations, or the equilibrium of forces, is capable of being
treated by reasoning a priori entirely, without any appeal to experience. This will appear, when the subject of Mechanics
is more particularly treated of.
DISSERTATION FOURTH.
587
der certain conditions, it may be attended with
the greatest advantage. He knew also in what
manner this application had been abused by the
Platonists, who had attempted, by means of geo¬
metry, to establish the first principles of Physics,
or had used them, in axiomalis constituendis, which
is exactly the province belonging exclusively to
experience. At the same time, he pointed out,
with great precision, the place which the Mathe¬
matics may legitimately occupy, as serving to
measure and compare the objects of physical in¬
quiry. He did not, however, perceive before¬
hand, nor was it possible that he should, the vast
extent to which the application of that science
was capable of being carried. In the book De
Augmentis, he has made many excellent remarks
on this subject, full of the sagacity which pene¬
trated so far into futurity, but, nevertheless,
could only perceive a small part of the scene
which the genius of Newton was afterwards to
unfold.
Hence, the route which leads to many of the
richest and most fertile fields of science, is not
precisely that which Bacon pointed out; it is
safer and easier; so that the voyager finds he
can trust to his chart and compass alone, with¬
out constantly looking out, or having the sound¬
ing-line perpetually in his hand.
Another remark I must make on Bacon’s me¬
thod is, that it does not give sufficient import¬
ance to the instantice radii, or those which fur¬
nish us with accurate measures of physical quan¬
tities. The experiments of this class are intro¬
duced as only subservient to practice ; they are,
however, of infinite value in the theoretical part
of induction, or for ascertaining the causes and
essences of the things inquired into. We have
an instance of this in the discovery of that im¬
portant truth in physical astronomy, that the
moon is retained in her orbit by the force of
gravity, or the same which, at the earth’s sur¬
face, makes a stone fall to the ground. This
proposition, however it might have been sus¬
pected to be true, could never have been demon¬
strated but by such observations and experiments
as assigned accurate geometrical measures to the
quantities compared. The semidiameter of the
earth; the velocity of falling bodies at the earth’s
surface; the distance of the moon, and her ve¬
locity in her orbit;—all these four elements must
have been determined with great precision, and
afterwards compared together by certain theo¬
rems deduced from the laws of motion, before the
relation between the force which retains the moon
in her orbit, and that which draws a stone to
the ground, could possibly be discovered. The
discovery also, when made, carried with it the
evidence of demonstration; so that here, as in
many other cases, the instantice radii are of the
utmost importance in the theoretical part of
Physics.
Another thing to be observed is, that, in many
cases, the result of a number of particular facts,
or the collective instance arising from them, can
only be found out by geometry, which, there¬
fore, becomes a necessary instrument in com¬
pleting the work of induction. An example,
which the science of optics furnishes, will make
this clearer than any general description. When
light passes from one transparent medium to
another, it is refracted, that is, it ceases to go on
in a straight line, and the angle which the inci¬
dent ray makes with the superficies which bounds
the two media, determines that which the refract¬
ed ray makes with the same superficies. Now,
if we would learn any thing about the relation
which these angles bear to one another, we must
have recourse to experiment; and all that experi¬
ment can do is, for any particular angle of inci¬
dence, to determine the corresponding angle of
refraction. This may be done in innumerable
cases; but, with respect to the general rule which,
in every possible case, determines the one of those
angles from the other, or expresses the constant
and invariable relation which subsists between
them,—with respect to it, experiment gives no
direct information. The methods of geometrv
must therefore be called in to our assistance,
which, when a constant though unknown relation
subsists between two angles, or two variable
quantities of any kind, and when an indefinite
number of values of those quantities are given,
furnishes infallible means of discovering that
unknown relation, either accurately, or at least
by approximation. In this way it has been
found, that, when the two media remain the
same, the cosines of the angles above mentioned
have a constant ratio to one another. Thus
588
preliminary dissertations.
it appears, that, after experiment lias done
its utmost, geometry must he applied before
the business of induction can be completed.
This can only happen when the experiments af¬
ford accurate measures of the quantities con¬
cerned, like the instccfitioz cuTTiculi^ &c.,
and this advantage of admitting generalization
with so much certainty is one of their proper¬
ties, of which it does not appear that even Ba¬
con himself was aware.
Again, from the intimate connection which
prevails among the principles of science, the suc¬
cess of one investigation must often contribute
to the success of another, in such a degree as to
make it unnecessary to employ the complete ap¬
paratus of induction from the beginning. When
certain leading principles have been once esta¬
blished, they serve, in new investigations, to
narrow the limits within which the thing sought
for is contained, and enable the inquirer to arrive
more speedily at the truth.
Thus, suppose that, after the nature of the
reflection and refraction of light, and particu¬
larly of the colours produced by the latter, had
been discovered by experiment, the cause of the
rainbow were to be inquired into. It would,
after a little consideration, appear probable, that
the phenomenon to be explained depends on the
reflection and refraction of light by the rain fall¬
ing from a cloud opposite to the sun. Now,
since the nature of reflection and refraction are
supposed known, we have the principles previ¬
ously ascertained which are likely to assist in
the explanation of the rainbow. We have no
occasion, therefore, to enter on the inquiry, as
if the powers to be investigated were wholly un¬
known. It is the combination of them only
which is unknown, and our business is to seek
so to combine them, that the result may corre¬
spond with the appearances. This last is precise¬
ly what Newton accomplished, when, by deduc¬
ing from the known laws of refraction and re¬
flection the breadth of the coloured arch, the dia¬
meter of the circle of which it is a part, and the
relation of the latter to the place of the specta¬
tor and of the sun, he found all these to come
out from his calculus, just as they are observed
in nature. Thus he proved the truth of his solu¬
tion by the most clear and irresistible evidence.
The strict method of Bacon is therefore oidy
necessary where the thing to be explained is new,
and where we have no knowledge, or next to
none, of the powers employed. This is but rare¬
ly the case, at least in some of the branches of
Physics; and, therefore, it occurs most common¬
ly in actual investigation, that the inquirer finds
himself limited, almost from the first outset, to
two or three hypotheses, all other suppositions
involving inconsistencies which cannot for a
moment be admitted. His business, therefore,
is to compare the results of these hypotheses, and
to consider what consequences may in any case
arise from the one that would not arise from
the other. If any such difference can be found,
and if the matter is a subject of experiment, we
have then an instantia crucis which must decide
the question.
Thus, the instantia crucis comes in real prac¬
tice to be the experiment most frequently ap¬
pealed to, and that from which the most valu¬
able information is derived.
In executing the method here referred to, the
application of much reasoning, and frequently
of much mathematical reasoning, is necessary,
before any appeal to the experiment can be made,
in order to deduce from each of the hypotheses
an exact estimate of the consequences to which
it leads. Suppose, for instance, that the law by
which the magnetic virtue decreases in its in¬
tensity, as we recede from its poles, were to be
inquired into. It is obvious tbat the number of
hypotheses is here indefinite; and that we have
hardly any choice but to begin with the simplest,
or with that which is most analogous to the law
of other forces propagated from a centre. What¬
ever law we assume, we must enter into a good
deal of geometric reasoning, before a conclusion
can be obtained, capable of being brought to the
test of experience. The force itself, like all other
forces, is not directly perceived, and its effects
are not the result of its mere intensity, but of
that intensity combined with the figure and mag¬
nitude of the body on which it acts; and, there¬
fore, the calculus must be employed to express
the measure of the effect, in terms of the inten¬
sity and the distance only. This being done, the
hypothesis which gives results most nearly cor¬
responding to the facts observed, when the mag-
DISSERTATION FOURTH.
539
net acts on the same body, at different distances,
must be taken as the nearest approximation to
the truth. We have here an instance of the use
of hypothesis in inductive investigation, and, in¬
deed, of the only legitimate use to which it can
ever be applied.
It also appears that Bacon placed the ultimate
object of philosophy too high, and too much out
of the reach of man, even when his exertions
are most skilfully conducted. He seems to have
thought, that, by giving a proper direction to
our researches, and carrying them on according
to the inductive method, we should arrive at the
knowledge of the essences of the powers and
qualities residing in bodies; that we should, for
instance, become acquainted with the essence of
heat, of cold, of colour, of transparency. The
fact however is, that, in as far as science has
yet advanced, no one essence has been dis¬
covered, either as to matter in general, or as to
any of its more extensive modifications. We
are yet in doubt, whether heat is a peculiar mo¬
tion of the minute parts of bodies, as Bacon him¬
self conceived it to be; or something emitted or
radiated from their surfaces; or lastly, the vi¬
brations of an elastic medium, by which they
are penetrated and surrounded. Yet whatever
be the form or essence of heat, we have disco¬
vered a great number of its properties and its
laws; and have done so, by pursuing with more
or less accuracy the method of induction. We
have also this consolation for the imperfection
of our theoretical knowledge, that, in as much
as art is concerned, or the possession of power-
over heat, we have perhaps all the advantages
that could be obtained from a complete know¬
ledge of its essence.
An equal degree of mystery hangs over the
other properties and modifications of body;
light, electricity, magnetism, elasticity, gravity,
are all in the same circumstances; and the only
advance that philosophy has made toward the
discovery of the essences of these qualities or
substances is, by exploding some theories, rather
than by establishing any,—so true is Bacon’s
maxim, that the first steps in philosophy neces¬
sarily consist in negative propositions. Besides
this, in all the above instances the laws of ac¬
tion have been ascertained; the phenomena
have been reduced to a few general facts, and
in some cases, as in that of gravity, to one
only; and for aught that yet appears, this is
the highest point which our science is destined
to reach.
In consequence of supposing a greater perfec¬
tion in knowledge than is ever likely to be at¬
tained, Bacon appears, in some respects, to have
misapprehended the way in which it is ultimate¬
ly to become applicable to art. He conceives
that, if the form of any quality were known, we
should be able, by inducing that form on any
body, to communicate to it the said quality. It
is not probable, however, that this would often
lead to a more easy and simple process than that
which art has already invented. In the case of
colour, for example, though ignorant of its form,
or of the construction of surface which enables
bodies to reflect only light of a particular spe¬
cies, yet we know how to communicate that
power from one body to another. Nor is it
likely, though this structure were known with
ever so great precision, that we should be able
to impart it to bodies by any means so simple
and easy, as by the common process of immersing
them in a liquid of a given colour.
In some instances, however, the theories of
Chemistry have led to improvements of art very
conformable to the anticipations of the Novum
Organum. A remarkable instance of this occurs
in the process for bleaching, invented by Ber-
thollet. It had been for some time known, that
the combination of the chemical principle of
oxygen with the colouring matter in bodies,
destroyed or discharged the colour; and that,
in the common process of bleaching, it was
chiefly by the union of the oxygen of the air
with the colouring matter in the cloth that this
effect was produced. The excellent chemist
just named conceived, therefore, that if the oxy¬
gen could be presented to the cloth in a dense
state, and, at the same time, feebly combined
with any other body, it might unite itself to the
colouring matter so readily, that the process of
bleaching would by that means be greatly acce¬
lerated. His skill in Chemistry suggested to him
a way in which this might easily be done, by
immersing the cloth in a liquid containing much
oxygen in a loose state, or one in which it was
590
PRELIMINARY DISSERTATIONS,
slightly combined with other substances; and
the effect followed so exactly, that he was able
to perform in a few hours what required weeks,
and even months, according to the common pro¬
cess. This improvement, therefore, was a real
gift from the sciences to the arts; and came
nearly, though not altogether, up to the ideas of
Bacon. I suspect not altogether, because the
manner in which oxygen destroys the colour of
bodies, or alters the structure of their surfaces,
remains quite unknown.
It was natural, however, that Bacon, who
studied these subjects theoretically, and saw
nowhere any practical result in which he could
confide, should listen to the inspirations of his
own genius, and ascribe to philosophy a perfec¬
tion which it may be destined never to attain.
He knew, that from what it had not yet done,
he could conclude nothing against what it might
hereafter accomplish. But after his method
has been followed, as it has now been, with
greater or less accuracy, for more than two hun¬
dred years, circumstances are greatly changed,
and the impediments which, during all that
time, have not yielded in the least to any effort,
are perhaps never likely to be removed. This
may, however, be a rash inference; Bacon, after
all, may be in the right; and we may be judg¬
ing under the influence of the vulgar prejudice,
which has convinced men in every age, that they
had nearly reached the farthest verge of human
knowledge. This must be left for the decision
of posterity; and we should rejoice to think,
that judgment will hereafter be given against
the opinion which at this moment appears most
probable.
SECTION III.
MECHANICS.
1. THEORY OF MOTION.
Before the end of the sixteenth century, me¬
chanical science had never gone beyond the
problems which treat of the equilibrium of bo¬
dies, and had been able to resolve these accu¬
rately, only in the cases which can be easily re¬
duced to the lever. Guido Ubaldi, an Italian
mathematician, was among the first who at¬
tempted to go farther than Archimedes and the
ancients had done in such inquiries. In a trea¬
tise which bears the date of 1577, he reduced
the pulley to the lever; but with respect to the
inclined plane, he continued in the same error
with Pappus Alexandrinus, supposing that a
certain force must be applied to sustain a body,
even on a plane which has no inclination.
Stevinus, an engineer of the Low Countries,
is the first who can he said to have passed be¬
yond the point at which the ancients had stopp¬
ed, by determining accurately the force neces¬
sary to sustain a body on a plane inclined at any
angle to the horizon. He resolved also a great
number of other problems connected with the
preceding, hut, nevertheless, did not discover
the general principle of the composition of forces,
though he became acquainted with this particu¬
lar case, immediately applicable to the inclined
plane.
The remark, that a chain laid on an inclined
plane, with a part of it hanging over at top, in
a perpendicular line, will be in equilibria, if the
two ends of the chain reach down exactly to the
same level, led him to the conclusion, that a
body may be supported on such a plane by a
force which draws in a direction parallel to it,
and has to the weight of the body the same ratio
that the height of the plane has to its length.
Though it was probably from experience that
Stevinus derived the knowledge of this propo¬
sition, he attempted to prove the truth of it by
reasoning a priori. He supposed the two ex-
DISSEKTATION FOURTH.
591
tremities of the chain, when disposed as above,
to be connected by a part similar to the rest,
which, therefore, must hang down, and form an
arch. If in this state, says he, the chain were
to move at all, it would continue to move for
ever, because its situation, on the whole, never
changing, if it were determined to move at one
instant, it must be so determined at every other
instant. Now, such perpetual motion, he adds,
is impossible; and therefore the chain, as here
supposed, with the arch hanging below, does
not move. But the force of the arch below
draws down the ends of the chain equally, be¬
cause the arch is divided in the middle or low¬
est point into two parts similar and equal. Take
away these two equal forces, and the remaining
forces will also be equal; that is, the tendency of
the chain to descend along the inclined plane, and
the opposite tendency of the part hanging per¬
pendicularly down, are equal, or are in equilibrio
with one another. Such is the reasoning of
Stevinus, which, whether perfectly satisfactory
or not, must be acknowledged to be extremely
ingenious, and highly deserving of attention, as
having furnished the first solution of a problem,
by which the progress of mechanical science had
been long arrested. The first appearance of Ins
solution is said to have had the date of 1585;
but his works, as we now see them, were col¬
lected after his death, by his countryman Albert
Girard, and published at Leyden in 1634.1 Some
discoveries of Stevinus in hydrostatics will be
hereafter mentioned.
The person who comes next in the history of
mechanics made a great revolution in the phy¬
sical sciences. Galileo was born at Pisa in the
year 1564. tie early applied himself to the
study of Mathematics and Natural Philosophy;
and it is from the period of his discoveries that
we are to date the joint application of experi¬
mental and geometrical reasoning to explain the
phenomena of nature.
As early as 1592 he published a treatise, della
Scienza Mechanica, in which he has given the
theory, not of the lever only, but of the inclined
plane and the screw; and has also laid down
this general proposition, that mechanical engines
make a small force equivalent to a great one,
by making the former move over a greater space
in the same time than the latter, just in propor¬
tion as it is less. No contrivance can make a
small weight put a great one in motion, but
such a one as gives to the small weight a velo¬
city which is as much greater than that of the
large weight, as this last weight is greater than
the first. These general propositions, and their
influence on the action of machinery, Galileo
proceeded to illustrate with that clearness, sim¬
plicity, and extent of view, in which he was
quite unrivalled; and hence, I think, it is fair
to consider him as the first person to whom the
mechanical principle, since denominated that of
the virtual velocities^ had occurred in its full ex¬
tent. The object of his consideration was the
action of machines in motion, and not merely of
machines in equilibrio, or at rest; and he show¬
ed, that if the effect of a force be estimated by
the weight it can raise to a given height in a
given time, this effect can never be increased by
any mechanical contrivance whatsoever.
In the same treatise, he lays it down as a pos¬
tulate, (supposizione) that the effect of one heavy
body to turn another round a centre of motion,
is proportional to the perpendicular drawn from
that centre to the vertical passing through the
body, or in general to the direction of the force.
This proposition he states without a demonstra¬
tion, and passes by means of it to the oblique
lever, and thence to the inclined plane. To
speak strictly, however, the demonstrations with
respect to both these last are incomplete, the
preceding proposition being assumed in them
without proof. It is probable that he satisfied
himself of the truth of it, on the principle, that
the distances of forces from the centre of motion
must always he measured by lines making the
same angles with their directions, and that of
such lines the simplest are the perpendiculars.
His demonstration is regarded by La Grange as
quite satisfactory.2
/ n6 e«1ftl°l1 °* ^lbert Girard is entitled (Euvres Mathematiques de Stevins, in folio. See livre i. De la Statique, tlid<
<^1 un A!* MevinVs .so wfot^ a treatise on Navigation, which was published in Flemish in 158G, and was afterwards honoui
. 1 j translation into Latin, by Grotius. The merit of Stevinus has been particularly noticed by La Grange. (Mt
canique Analytique, tom. I. sect. 1. § 5.) ' J J b v
■ Mtcanique Analytique, tom. I. sect. 1. § G.
592
preliminary dissertations.
\
Galileo extended the theory of motion still
farther. He had begun, while pursuing his stu¬
dies at the University of Pisa, to make expeii-
ments on the descent of falling bodies, and dis¬
covered the fact, that heavy and light bodies fall
to the ground from the same height in the same
time, or in times so nearly the same that the
difference can only be ascribed to the resistance
of the air. From observing the vibrations of
the lamps in the cathedral, he also arrived at
this very important conclusion in mechanics,
that the great and the small vibrations of the
same pendulum are performed in the same time,
and that this time depends only on the length of
the pendulum. The date of these observations
goes back as far as the year lo83.
These experiments drew upon him the dis¬
pleasure of his masters, who considered it as
unbecoming of their pupil to seek for truth in the
Book of Nature, rather than in the writings of
Aristotle, when elucidated by their commen¬
taries ; and from that moment began the perse¬
cutions with which the prejudice, the jealousy,
and bigotry of his contemporaries continued to
harass or afflict this great man throughout his
whole life.
That the acceleration of falling bodies is uni¬
form, or, that they receive equal increments of
velocity in equal times, he appears first to have
assumed as the law which they follow, merely
on account of its simplicity. Having once as¬
sumed this principle, he showed, by mathema¬
tical reasoning, that the spaces descended through
must be as the squares of the times, and that
the space fallen through in one second is just the
half of that which the body would have described
in the same time with the velocity last acquired.
The knowledge which he already had of the
properties of the inclined plane enabled him
very readily to perceive, that a body descending
on such a plane must be uniformly accelerated,
though more slowly than when it falls directly,
and is accelerated by its whole weight. By
means of the inclined plane, therefore, he was
able to bring the whole theory of falling bodies
to the test of experiment, and to prove the truth
of his original assumption, the uniformity of
their acceleration.
His next step was to determine the path of
a heavy body, when obliquely projected. He
showed this path to be a parabola; and here,
for the first time, occurs the use of a principle
which is the same with the composition of mo¬
tion in its full extent. Galileo, however, gave
no name to this principle; he did not enunciate
it generally, nor did he give any demonstration
of it, though he employed it in his reasonings.
The inertia of body was assumed in the same
manner ; it was, indeed, involved in the uniform
acceleration of falling bodies; for these bodies
did not lose in one minute the motion acquired
in the preceding, but, retaining it, went on con¬
tinually receiving more.
The theory of the inclined plane had led to the
knowledge of this proposition, that it a ciicle
be placed vertically, the chords of different arches
terminating in the lowest point of the ciicle,
are all descended through in the same space of
time. This seemed to explain why, in a circle,
the great and the small vibrations are of equal
duration. Here, however, Galileo was under a
mistake, as the motions in the choi d and in the
arch are very dissimilar. The accelerating force
in the chord remains the same from the begin¬
ning to the end, but in the arch it v aiics con¬
tinually, and becomes, at the lowest point, equal
to nothing. The times in the chords, and in the
arches, are therefore different, so that here we
have a point marking the greatest distance in
this quarter, to which the mechanical discoveries
of Galileo extended. The first person who in¬
vestigated the exact time of a vibration in an
arch of a circle was Huygens, a very profound
mathematician.
To this list of mechanical discoveries, already
so important and extensive, we must add, that
Galileo was the first who maintained the ex¬
istence of the laiv of continuity, and who made
use of it as a principle in his reasonings on the
phenomena of motion.1
The vibrations of the pendulum having sug¬
gested to Galileo the means of measuring time
1 Oi>ae di Galileo, tom. IV. dial. i. p. 32, Florence edition, and in many other parts.
DISSERTATION FOURTH.
593
accurately, it appears certain that the idea of
applying it to the clock had also occurred to
him, and of using the chronometer so formed for
finding the longitude, by means of observations
made on the eclipses of the satellites of Jupiter.
How far he had actually proceeded in an inven¬
tion which required great practical knowledge,
and which afterwards did so much credit to
Huygens, appears to be uncertain, and not now
easy to be ascertained. But, that the project
had occurred to him, and that he had taken
some steps towards realizing it, is sufficiently
established.
One forms, however, a very imperfect idea of
this philosopher, from considering the discove¬
ries and inventions, numerous and splendid as
they are, of which he was the undisputed au¬
thor. It is by following his reasonings, and by
pursuing the train of his thoughts in his own
elegant, though somewhat diffuse exposition of
them, that we become acquainted with the fer¬
tility of his genius, with the sagacity, penetra¬
tion, and comprehensiveness of his mind. The
service which he rendered to real knowledge is
to be estimated, not only from the truths which
he discovered, but from the errors which he de¬
tected,—not merely from the sound principles
which he established, but from the pernicious
idols which he overthrew. His acuteness was
strongly displayed in the address with which he
exposed the errors of his adversaries, and refuted
their opinions, by comparing one part of them
with another, and proving their extreme incon¬
sistency. Of all the writers who have lived in
an age which was yet only emerging from ig¬
norance and barbarism, Galileo has most entire¬
ly the tone of true philosophy, and is most free
from any contamination of the times, in taste,
sentiment, and opinion.
The discoveries of this great man concerning
motion drew the attention of philosophers more
readily, from the circumstance that the astro¬
nomical theories of Copernicus had directed their
attention to the same subject. It had become
evident, that the great point in dispute between
his system and the Ptolemaic must be finally
decided by an appeal to the nature of motion
and its laws. The great argument to which the
friends of the latter system naturally had re¬
course, was the impossibility, as it seemed to
them to be, of the swift motion of the earth be¬
ing able to exist, without the perception, nay,
even without the destruction of its inhabitants.
It was natural for the followers of Copernicus
to reply, that it was not certain that these two
things were incompatible ,* that there were many
cases in which it appeared, that the motion
common to a whole system of bodies did not
affect the motion of those bodies relatively to one
another; that the question must be more deeply
inquired into; and that, without this, the evi¬
dence on opposite sides could not be fairly and
accurately compared. Thus, it was at a very
fortunate moment that Galileo made his disco¬
veries in mechanics, as they were rendered
more interesting by those which, at that very
time, he himself was making in astronomy.
The system of Copernicus had, in this manner,
an influence on the theory of motion, and, of
course, on all the parts of Natural Philosophy.
The inertia of matter, or the tendency of body,
when put in motion, to preserve the quantity
and direction of that motion, after the cause
which impressed it has ceased to act, is a prin¬
ciple which might still have been unknown, if
it had not been forced upon us by the discovery
of the motion of the earth.
The first addition which was made to the me¬
chanical discoveries of Galileo was by Torricelli,
in a treatise De Motu Gravium naturaliter de-
scendentium et projectorum.1 To this ingenious
man we are indebted for the discovery of a re¬
markable property of the centre of gravity, and
a general principle with respect to the equi¬
librium of bodies. It is this: If there be any
number of heavy bodies connected together, and
so circumstanced, that by their motion their
centre of gravity can neither ascend nor descend,
these bodies will remain at rest. This proposi¬
tion often furnishes the means of resolving very
difficult questions in mechanics.
Descartes, whose name is so great in philoso¬
phy and mathematics, has also a place in the
history of mechanical discovery. With regard
4 V
DISS. IV., PART I.
Vitir Italorum Illustrium, vol. I. p. 347.
594
preliminary dissertations.
to the action of machines, he laid down the same
principle which Galileo had established,-that
an equal effort is necessary to give to a weight a
certain velocity, as to give to double the weight
the half of that velocity, and so on in proportion,
the effect being always measured by the weight
multiplied into the velocity which it receives.
He could hardly be ignorant that this proposi¬
tion had been already stated by Galileo, but he
has made no mention of it. He indeed always
affected a disrespect for the reasonings and opin¬
ions of the Italian philosopher, which has done
him no credit in the eyes of posterity.
The theory of motion, however, has in some
points been considerably indebted to Descartes.
Though the reasonings of Galileo certainly in¬
volve the knowledge of the disposition which
matter has to preserve its condition either of
rest or of rectilineal and uniform motion, the
first distinct enunciation of this law is found in
the writings of the French philosopher. It is,
however, there represented, not as mere inacti¬
vity, or indifference, but as a real force, which
bodies exert in order to preserve their state of
rest or of motion; and this inaccuracy affects
some of the reasonings concerning their action
on one another.
Descartes, however, argued very justly, that
all motion being naturally rectilineal, when a
body moves in a curve, this must arise from
some constraint, or some force urging it in a
direction different from that of the first impulse,
and that if this cause were removed at any time,
the motion would become rectilineal, and would
be in the direction of a tangent, to the curve at
the point where the deflecting force ceased to act.
Lastly, he taught that the quantity of motion
in the universe remains always the same.
The reasoning by which he supported the first
and second of these propositions is not very con¬
vincing; and though he might have appealed to
experience for the truth of both, it was not in
the spirit of his philosophy to take that method
of demonstrating its principles. His argument
was, that motion is a state of body, and that
body or matter cannot change its own state.
This was his demonstration of the first proposi¬
tion, from which the second followed necessarily.
The evidence produced for the third, or the
preservation of the same quantity of motion in
the universe, is founded on the immutability of
the Divine nature, and is an instance of the in¬
tolerable presumption which so often distinguish¬
ed the reasonings of this philosopher. Though
the immutability of the Divine nature will
readily be admitted, it remains to be shown, that
the continuance of the same quantity of motion
in the universe is a consequence of it. This, in¬
deed, cannot be shown ; for that quantity, in the
sense in which Descartes understood it, is so far
from being preserved uniform, that it varies con-
tinuallv from one instant to another. It is ne¬
vertheless true, that the quantity of motion in
the universe, when rightly estimated, is inva¬
riable, that is, when reduced to the direction of
three axes at right angles to one another, and
when opposite motions are supposed to have op¬
posite signs. This is a truth now perfectly un¬
derstood, and is a corollary to the equality of
action and reaction, in consequence of which,
whatever motion is communicated in one direc¬
tion, is either lost in that direction, or generated
in the opposite. This, however, is quite differ¬
ent from the proposition of Descartes, and if ex¬
pressed in his language, would assert, not that
the sum, but that the difference of the opposite
motions in the universe remains constantly the
same. When he proceeds, by help of the prin¬
ciple which he had thus mistaken, to determine
the laws of the collision of bodies, his conclu¬
sions are almost all false, and have indeed such
a want of consistency and analogy with one an¬
other as ought, in the eyes of a mathematician,
to have appeared the most decisive indications of
error. How this escaped the penetration of a
man well acquainted with the harmony of geo¬
metrical truths, and the gradual transitions by
which they always pass into one another, is not
easily explained, and perhaps, of all his errors,
is the least consistent with the powerful and sys¬
tematic genius which he is so well known to
have possessed.
Thus, the obligation which the theory of mo¬
tion has to this philosopher, consists in his hav¬
ing pointed out the nature of centrifugal force,
and ascribed that force to the true cause, the in¬
ertia of body, or its tendency to uniform and
rectilineal motion.
DISSERTATION FOURTH.
595
The laws which actually regulate the collision
of bodies remained unknown till some years later,
when they were recommended by the Royal So¬
ciety of London to the particular attention of its
members. Three papers soon appeared, in which
these laws were all correctly laid down, though
no one of the authors had any knowledge of the
conclusions obtained by the other two. The first
of these was read to the Society, in November
1668, by Dr Wallis of Oxford; the next by Sir
Christopher Wren in the month following; and
the third by Huygens in January 1669. The
equality of action and reaction, and the maxim,
that the same force communicates to different
bodies velocities which are inversely as their
masses, are the principles on which these inves¬
tigations are founded.
The ingenious and profound mathematician
last mentioned is also the first who explained
the true relation between the length of a pendu¬
lum and the time of its least vibrations, and
gave a rule by which the time of the rectilineal
descent, through a line equal in length to the
pendulum, might from thence be deduced. He
next applied the pendulum to regulate the mo¬
tion of a clock, and gave an account of his
construction, and the principles of it, in his
Horologium Oscillatorium, about the year 1670,
though the date of the invention goes as far
back as 1656.1 Lastly, he taught how to cor¬
rect the imperfection of a pendulum, by making
it vibrate between cycloidal cheeks, in conse¬
quence of which its vibrations, whether great or
small, became, not approximately, but precisely
of equal duration.
Robert Hooke, a very celebrated English me¬
chanician, laid claim to the same application of
the pendulum to the clock, and the same use of
the cycloidal cheeks. There is, however, no dis¬
pute as to the priority of Huygens’s claim, the
invention of Hooke being as late as 1670. Of
the cycloidal cheeks, he is not likely to have
been even the second inventor. Experiment
could hardly lead any one to this discovery, and
he was not sufficiently skilled in the Mathema¬
tics to have found it out by mere reasoning.
The fact is, that though very original and in¬
ventive, Hooke was jealous and illibeial in the
extreme; he appropriated to himself the inven¬
tions of all the world, and accused all the world
of appropriating his.
It has already been observed, that Galileo
conceived the application of the pendulum to
the clock earlier, by several years, than either
of the periods just referred to. The invention
did great honour to him and to his two rivals;
but that which argues the most profound think¬
er, and the most skilful mathematician of the
three, is the discovery of the relation between
the length of the pendulum and the time of
its vibration, and this discovery belongs ex¬
clusively to Huygens. The method which he
followed in his investigation, availing himself
of the properties of the cycloid, though it be
circuitous, is ingenious, and highly instruc¬
tive.
An invention, in which Hooke has certainly
the priority to any one, is the application of a
spiral spring to regulate the balance of a watch.
It is well known of what practical utility this
invention has been found, and how much it has
contributed to the solution of the problem of
finding the longitude at sea, to which not only
he, but Galileo and Huygens, appear all to have
had an eye.
In what respects the theory of motion, Huy¬
gens has still another strong claim to our notice.
This arises from his solution of the problem of
finding the centre of oscillation of a compound
pendulum, or the length of the simple pendulum
vibrating in the same time with it. Without
the solution of this problem, the conclusions re¬
specting the pendulum were inapplicable to the
construction of clocks, in which the pendulums
used are of necessity compound. The problem
was by no means easy, and Huygens was oblig¬
ed to introduce a principle which had not before
been recognised, that if the compound pendu¬
lum, after descending to its lowest point, were to
be separated into particles distinct and uncon¬
nected with one another, and each left at liberty
to continue its own vibration, the common centre
of gravity of all those detached weights would
ascend to the same height to which it would
1 Monthcla, tom. II. p. 418, 2d edit.
596
PRELIMINARY DISSERTATIONS.
have ascended had they continued to constitute given, does great credit to his ingenuity. This
one body. The above principle led him to the was the most difficult mechanical inquiry which
true solution; and his investigation, though less preceded the invention of the differential or
satisfactory than those which have been since fluxionary calculus.
2. HYDROSTATICS.
While the theory of motion, as applied to
solids, was thus extended, in what related to
fluids it was making equal progress. The laws
which determine the weight of bodies immersed
in fluids, and also the position of bodies floating
on them, had been discovered by Archimedes,
and were further illustrated by Galileo. It had
also been discovered by Stevinus, that the pres¬
sure of fluids is in proportion to their depth; and
thus the two leading principles of hydrostatics
were established. Hydraulics, or the motion of
fluids, was a matter of more difficulty; and here
the first step is to be ascribed to Torricelli, who,
though younger than Galileo, was for some time
his contemporary. He proved that water issues
from a hole in the side or bottom of a vessel,
with the velocity which a body would acquire by
falling from the level of the surface to the level
of the orifice. This proposition, now so well
known as the basis of the whole doctrine of hy¬
draulics, was first published by Torricelli at the
end of his book De Motu Gravium et Projecto-
rum ; but it is not the greatest discovery which
science owes to the friend and disciple of Galileo.
The latter had failed in assigning the reason
why water cannot be raised in pumps higher
than thirty-three feet; but he had remarked, that
if a pump is more than thirty-three feet in
length, a vacuum will be left in it. Torricelli,
reflecting on this, conceived, that if a heavier
fluid than water were used, a vacuum might be
produced, in a way far shorter and more com¬
pendious. He tried mercury, therefore, and
made use of a glass tube about three feet long,
open at one end, and close at the other, where
it terminated in a globe. He filled this tube,
shut it with his finger, and inverted it in a basin
of mercury. The result is well known: he
found that a column of mercury was suspended
in the tube, an effect which he immediately
ascribed to the pressure of the atmosphere. So
disinterested was this philosopher, however, that
he is said to have lamented that Galileo, when
inquiring into the cause why water does not
ascend in pumps above a certain height, had not
discovered the true cause of the phenomenon.
The generosity of Torricelli was perhaps rarer
than his genius. There are more who might
have discovered the suspension of mercury in
the barometer, than who would have been will¬
ing to part with the honour of the discovery to
a master or a friend.
This experiment opened the door to a multi¬
tude of new discoveries, and demolished a formi¬
dable idol, the horror of a vacuum, to which so
much power had been long attributed, and be¬
fore which even Galileo himself had condescend¬
ed to bow.
The objections which were made to the expla¬
nation of the suspension of the mercury in the
tube of the barometer, were overthrown by car¬
rying that instrument to the top of Puy de
Dome, an experiment suggested by Pascal. The
descent of the mercury showed, that the pressure
which supported it was less there than at the
bottom; and it was afterwards found, that the
fall of the mercury corresponded exactly to the
diminution of the length of the pressing column,
so that it afforded a measure of that diminution,
and, consequently, of the heights of mountains.
The invention of the air-pump by Otto Guericke,
burgomaster of Magdeburg, quickly followed
that of the barometer by Torricelli, though it
does not appear that the invention of the Italian
philosopher was known to the German. In
order to obtain a space entirely void of air, Otto
Guericke filled a barrel with water, and having
closed it exactly on all sides, began to draw out
the water by a sucking-pump applied to the
lower part of the vessel. He had proceeded but
a very little way, when the air burst into the bar¬
rel with a loud noise, and its weight was proved
by the failure of the experiment, as effectually
as it could have been by its success. After some
DISSERTATION FOURTH.
597
other trials, which also failed, he thought of em¬
ploying a sphere of glass, when the experiment
succeeded, and a vacuum was obtained. This
was about the year 1654.
The elasticity of the air, as well as its weight,
now became known; its necessity to combus¬
tion, and the absorption of a certain proportion
of it, during that process; its necessity for con¬
veying sound;—all these things were clearly de-
monstrateck The necessity of air to the respi¬
ration of animals required no proof from experi¬
ment; but the sudden extinction of life, by im¬
mersion in a vacuum, was a new illustration of
the fact.
The first considerable improvements made on
the air-pump are due to Mr Boyle. He substi¬
tuted to the glass globe of Otto Guericke a re¬
ceiver of a more commodious form, and con¬
structed his pump so as to be worked with much
more facility. His experiments were farther
extended,^—they placed the weight and elasti¬
city of the air in a variety of new lights,—they
made known the power of air to dissolve water,
&c. Boyle had great skill in contriving, and
great dexterity in performing experiments. He
had, indeed, very early applied himself to the
prosecution of experimental science, and was
one of the members of the small but distin¬
guished body who, during the civil wars, held
private meetings for cultivating natural know¬
ledge, on the plan of Bacon. They met first in
London, as early as 1645, afterwards at Oxford,
taking the name of the Philosophic College. Of
them, when Charles the Second ascended the
throne, was formed the Royal Society of Lon¬
don, incorporated by letters patent in 1662.
No one was more useful than Boyle in commu¬
nicating activity and vigour to the new institu¬
tion. A real lover of knowledge, he was most
zealous in the pursuit of it; and having tho¬
roughly imbibed the spirit of Bacon, was an
avowed enemy to the philosophy of Aristotle.
SECTION IV.
ASTRONOMY.
1. ANCIENT ASTRONOMY.
It has already been remarked, that the an¬
cients made more considerable advances in as¬
tronomy than in almost any other of the physi¬
cal sciences. They applied themselves diligently
to observe the heavens, and employed mathema¬
tical reasoning to connect together the insulated
facts, which are the only objects of direct ob¬
servation. The astronomer discovers nothing
by help of his instruments, but that, at a given
instant, a certain luminous point has a particu¬
lar position in the heavens. The application of
mathematics, and particularly of spherical trigo¬
nometry, enables him to trace out the precise
track of this luminous spot; to discover the rate
of its motion, whether varied or uniform; and
thus to resolve the first great problem which
the science of astronomy involves, viz. to ex¬
press the positions of the heavenly bodies, rela¬
tively to a given plane in functions of the time.
The problem, thus generally enunciated, com¬
prehends all that is usually called by the name
of descriptive or mathematical astronomy.
The explanation of the celestial motions, which
naturally occurred to those who began the study
of the heavens, was, that the stars are so many
luminous points fixed in the surface of a sphere,
having the earth in its centre, and revolving on
an axis passing through that centre in the space
of twenty-four hours. When it was observed
that all the stars did not partake of this diurnal
motion in the same degree, but that some were
carried slowly towards the east, and that their
paths estimated in that direction, after certain
intervals of time, returned into themselves, it
598
PRELIMINARY DISSERTATIONS.
was believed that they were fixed in the sur¬
faces of spheres, which revolved westward more
slowly than the sphere of the fixed stars. These
spheres must he transparent, or made of some
crystalline substance; and hence the name of the
crystalline spheres, by which they are distin¬
guished. This system, though it grew more
complicated in proportion to the number and
variety of the phenomena observed, was the
system of Aristotle and Eudoxus, and, with a few
exceptions, of all the philosophers of antiquity.
But when the business of observation came
to be regularly pursued,—when Timocharis and
Aristillus, and their successors in the Alexan¬
drian school, began to study the phenomena of
the heavens,—little was said of these orbs; and
astronomers seemed only desirous of ascertain¬
ing the laws or the general facts concerning the
planetary motions.
To do this, however, without the introduction
of hypothesis, was certainly difficult, and pro¬
bably was then impossible. The simplest and
most natural hypothesis was, that the planets
moved eastward in circles, and at a uniform
rate. But when it was found that, instead of
moving uniformly to the eastward, every one of
them was subject to great irregularity, the mo¬
tion eastward becoming at certain periods slower,
and at length vanishing altogether, so that the
planet became stationary, and afterwards ac¬
quiring a motion in the contrary direction, pro¬
ceeded for a time toward the west, it was far
from obvious how all these appearances could be
reconciled with the idea of a uniform circular
motion.
The solution of this difficulty is ascribed to
Apollonius Pergseus, one of the greatest geome¬
ters of antiquity. He conceived, that in the
circumference of a circle, having the earth for
its centre, there moved the centre of another
circle, in the circumference of which the planet
actually revolved. The first of these circles was
called the deferent, and the second the epicycle,
and the motion in the circumference of each
was supposed uniform. Lastly, it was conceived
that the motion of the centre of the epicycle in
the circumference of the deferent, and of the
planet in that of the epicycle, were in opposite
directions, the first being towards the east, and
the second towards the west. In this way, the
alterations from progressive to retrograde, with
the intermediate stationary points, were readily
explained; and Apollonius carried his investiga¬
tion so far as to determine the ratio between the
radius of the deferent and that of the epicycle,
from knowing the stations and retrogradations
of any particular planet.
An object, which was then considered as of
great importance to astronomy, was thus accom¬
plished, viz. the production of a variable motion,
or one which was continually changing hoth its
rate and its direction from two uniform circular
motions, each of which preserved always the
same quantity and the same direction.
It was not long before another application was
made of the method of epicycles. Hipparchus,
the greatest astronomer of antiquity, and one of
the inventors in science most justly entitled to
admiration, discovered the inequality of the sun’s
apparent motion round the earth. To explain
or to express this irregularity, the same observer
imagined an epicycle of a small radius with its
centre moving uniformly in the circumference
of a large circle, of which the earth was the
centre, while the sun revolved in the circumfer¬
ence of the small circle with the same angular
velocity as this last, hut in a contrary direction.
As other irregularities in the motions of the
moon and of the planets were observed, other
epicycles were introduced; and Ptolemy, in his
Almagest, enumerated all which then appeared
necessary, and assigned to them such dimensions
as enabled them to express the phenomena with
accuracy. It is not to be denied that the sys¬
tem of the heavens became in this way extreme¬
ly complicated ; though, when fairly examined,
it will appear to be a work of great ingenuity
and research. The ancients, indeed, may be re¬
garded as very fortunate in the contrivance ot
epicycles, because, by means of them, every in¬
equality which can exist in the angular motion
of a planet may be at least nearly represented.
This I call fortunate, because, at the time when
Apollonius introduced the epicycle, he had no
idea of the extent to which his contrivance would
go, as he could have none of the conclusions
which the author of the Mecanique Celeste was
to deduce from the principle of gravitation.
DISSERTATION FOURTH.
599
The same contrivance had another great ad¬
vantage; it subjected the motions of the sun, the
moon, and the planets, very readily to a geome¬
trical construction, or an arithmetical calcula¬
tion, neither of them difficult. By this means
the predictions of astronomical phenomena, the
calculation of tables, and the comparison of
those tables with observation, became matters
of great facility, on which facility, in a great
measure, the progress of the science depended.
It was on these circumstances, much more than
on the simplicity with which it amused or de¬
ceived the imagination, that the popularity of
this theory was founded,—the ascendant which
it gained over the minds of astronomers, and the
resistance which, in spite of facts and observa¬
tions, it was so long able to make to the true
system of the world.
It does not appear that the ancient astrono¬
mers ever considered the epicycles and deferents
which they employed in their system as having
a physical existence, or as serving to explain the
causes of the celestial motions. They seem to
have considered them merely as mathematical
diagrams, serving to express or to represent those
motions as geometrical expressions of certain
general facts, which readily furnished the rules
of astronomical calculation.
The language in which Ptolemy speaks of the
epicycles is not a little curious, and very con¬
formable to the notion, that he considered them
as merely the means of expressing a general law.
After laying down the hypothesis of certain epi¬
cycles, and their dimensions, it is usual with him
to add, “ these suppositions will save the pheno¬
mena.” Saxe is the literal translation of the
Greek word, which is always a part of the verb
Ss^e/i/, or some of its compounds. Thus, in treat¬
ing of certain phenomena in the moon’s motion,
he lays down two hypotheses, by either of which
they may be expressed; and he concludes, “ in
this way the similitude of the ratios, and the pro¬
portionality of the times, will be saved (biacutpim)
on both suppositions.” 1 It is plain, from these
words, that the astronomer did not here consi¬
der himself as describing any thing which ac¬
tually existed, but as explaining two artifices,
by either of which, certain irregularities in the
moon’s motion may be represented, in consist¬
ence with the principle of uniform velocity. The
hypothesis does not relate to the explanation,
but merely to the expression of the fact; it is
first assumed, and its merit is then judged of
synthetically, by its power to save, to reconcile,
or to represent appearances. At a time when
the mathematical sciences extended little beyond
the elements, and when problems which could
not be resolved by circles and straight lines
could hardly be resolved at all, such artifices as
the preceding were of the greatest value. They
were even more valuable than the truth itself
would have been in such circumstances; and
nothing is more certain than that the real
elliptical orbits of the planets, and the uni¬
form description of areas, would have been
very unseasonable discoveries at the period
we are now treating of. The hypotheses of epi¬
cycles and of centres of uniform motion were
well accommodated to the state of science,
and are instances of a false system which has
materially contributed to the establishment of
truth.
1 Mathematica Syntaxis, lib. iv. p. 223 of the Paris edition Milton, the extent and accuracy of whose erudition can
never be too much admired, had probably in view this phraseology of Ptolemy, when he wrote the following lines:
 He his fabric of the Heavens
Hath left to their disputes, perhaps to move
His laughter at their quaint opinions wide
Hereafter, when they come to model Heaven
And calculate the stars, how they will wield
The mighty frame, how build, unbuild, contrive
To save appearances, how gird the sphere
With centrick and eccentrick scribbled o’er,
Cycle and epicycle, orb in orb.
. The obsolete verb to salve is employed by Bacon, and many others of the old English writers, in the same sense with
in the work of Ptolemy here referred to. “ The schoolmen were like the astronomers, who, to salve phenomena, framed to
their conceit eccentricks and epicycles; so they, to salve the practice of the church, had devised a great number of strange
positions.” (Bacon.) 8 6
600
PRELIMINARY DISSERTATIONS.
2. COPERNICUS AND TYCHO.
On the revival of learning in Europe, astro¬
nomy was the first of the sciences which was le-
generated. Such, indeed, is the beauty and
usefulness of this branch of knowledge, that, in
the thickest darkness of the middle ages, the
study of it was never entirely abandoned. In
those times of ignorance, it also derived addi¬
tional credit from the assistance which it seem¬
ed to give to an imaginary and illusive science.
Astrology, which has exercised so durable and
extensive a dominion over the human mind, is
coeval with the first observations of astronomy.
In the middle ages, remarkable for the mixture
of a few fragments of knowledge and truth in a
vast mass of ignorance and error, it was assi¬
duously cultivated, and, in conjunction with
alchemy and magic, shared the favour of the
people, and the patronage of the great. During
the thirteenth and fourteenth centuries, it was
taught in the universities of Italy, and professors
were appointed, at Padua and Bologna, to in¬
struct their pupils in the influence of the stars.
Everywhere through Europe the greatest respect
was shown for this system of imposture; and
they who saw the deceit most clearly, could not
always avoid the disgrace of being the instru¬
ments of it. Astronomy, however, profited by
the illusion, and was protected for the great as¬
sistance which it seemed to afford to a science
more important than itself.
Of those who cultivated astronomy, many
were infected by this weakness, though some
were completely superior to it. Alphonso, the
King of Castile, was among the latter. He
flourished about the middle of the thirteenth
century, and was remarkable for such freedom
of thought, and such boldness of language, as it
required his royal dignity to protect. He ap¬
plied himself diligently to the study of astrono¬
my ; he perceived the inaccuracy of Ptolemy’s
tables, and endeavoured to correct their errors
by new tables of his own. These, in the course
of the next age, were found to have receded from
the heavens, and it became more and more evi¬
dent that astronomers had not yet discovered
the secret of the celestial motions.
Two of the men who, in the fifteenth century,
contributed the most to the advancement of as¬
tronomical science, Purbach and Regiomonta¬
nus, were distinguished also for their general
knowledge of the Mathematics. Purbach was
fixed at Vienna by the patronage of the Em¬
peror Frederick the Third, and devoted himself
to astronomical observation. He published a
new edition of the Almagest, and, though he
neither understood Greek nor Arabic, his know¬
ledge of the subject enabled him to make it
much more perfect than any of the former trans¬
lations. He is said to have been the first who
applied the plummet to astronomical instru¬
ments ; but this must not be understood strictly,
for some of Ptolemy’s instruments, the parallac¬
tic for instance, were placed perpendicularly by
the plumb-line.
Regiomontanus was the disciple of Purbach,
and is still more celebrated than his master. He
was a man of great learning and genius, most
ardent for the advancement of knowledge, and
particularly devoted to astronomy. To him we
owe the introduction of decimal fractions, which
completed our arithmetical notation, and form¬
ed the second of the three steps by which, in
modern times, the science of numbers has been
so greatly improved.
In the list of distinguished astronomers, the
name of Copernicus comes next, and stands at
the head of those men who, bursting the fetters
of prejudice and authority, have established
truth on the basis of experience and observation.
He was born at Thorn in Prussia, in 1473; he
studied at the University of Cracow, being in¬
tended at first for a physician, though he after¬
wards entered into the church. A decided taste
for astronomy led him early to the study of the
science in which he was destined to make such
an entire revolution; and as soon as he found him¬
self fixed and independent, he became a diligent
and careful observer.
It would be in the highest degree interesting
to know by what steps he was led to conceive
the bold system which removes the earth- from
the centre of the world, and ascribes to it a two-
DISSERTATION FOURTH.
601
fold motion. It is probable that the complica¬
tion of so many epicycles and deferents as were
necessary, merely to express the laws of the
planetary motions, had induced him to think of
all the possible suppositions which could be em¬
ployed for the same purpose, in order to discover
which of them was the simplest.
It appears extraordinary, that so natural a
thought should have occurred, at so late a period,
for the first, or nearly for the first time. We
are assured by Copernicus himself, that one of
the first considerations which offered itself to
his mind, was the effect produced by the motion
of a spectator, in transferring that motion to
the objects observed, but ascribing to it an op¬
posite direction.1 From this principle it imme¬
diately followed, that the rotation of the earth
on an axis, from west to east, would produce the
apparent motion of the heavens in the direction
from east to west.
In considering some of the objections which
might be made to the system of the earth’s mo¬
tion, Copernicus reasons with great soundness,
though he is not aware of the full force of his
own argument. Ptolemy had alleged, that if
the earth were to revolve on its axis, the violence
of the motion would be sufficient to tear it in
pieces, and to dissipate the parts. This argu¬
ment, it is evident, proceeds on a confused notion
of a centrifugal force, the effect of which the
Egyptian astronomer overrated, as much as he
undervalued the firmness and solidity of the
earth. Why, says Copernicus, was he not more
alarmed for the safety of the heavens, if the diur¬
nal revolution be ascribed to them, as their mo¬
tion must be more rapid, in proportion as their
magnitude is greater ? The argument here sug¬
gested, now that we know how to measure centri¬
fugal force, and to compare it with others, carries
demonstrative evidence with it; because that
force, if the diurnal revolution were really per¬
formed by the heavens, would be such as the
forces which hold together the frame of the ma¬
terial world would be wholly unable to resist.
There are, however, in the reasonings of Co¬
pernicus, some unsound parts, which show, that
the power of his genius was not able to dispel all
the clouds which in that age hung over the hu¬
man mind, and that the unfounded distinctions
of the Aristotelian Physics sometimes afforded
arguments equally fallacious to him and to his
adversaries. One of his most remarkable physi¬
cal mistakes was his misconception with respect
to the parallelism of the earth’s axis; to account
for which, he thought it necessary to assume, in
addition to the earth’s rotation on an axis, and
revolution round the sun, the existence of a third
motion altogether distinct from either of the
others. In this he was mistaken; the axis na¬
turally retains its parallelism, and it would re¬
quire the action of a force to make it do other¬
wise. This, as Kepler afterwards remarked, is
a consequence of the inertia of matter; and, for
that reason, he very justly accused Copernicus
of not being fully acquainted with his own
riches.
The first edition of the Aslronomia Instaurata,
the publication of which was solicited by Cardi¬
nal Schoenberg, and the book itself dedicated to
the Pope, appeared in 1543, a few days before
the death of the author. Throughout the whole
book, the new doctrine was advanced with great
caution, as if from a presentiment of the opposi¬
tion and injustice which it was one day to ex¬
perience. At first, however, the system attract¬
ed little notice, and was rejected by the greater
part even of astronomers. It lay fermenting in
secret with other new discoveries for more than
fifty years, till, by the exertions of Galileo, it
was kindled into so bright a flame as to consume
the philosophy of Aristotle, to alarm the hierar¬
chy of Rome, and to threaten the existence of
every opinion not founded on experience and
observation.
After Copernicus, Tycho Brahe was the most
distinguished astronomer of the sixteenth centu¬
ry. An eclipse of the sun which he witnessed
in 1560, when he was yet a very young man,
by the exactness with which it answered to the
prediction, impressed him with the greatest re¬
verence for a science which could see so far and
so distinctly into the future; and from that mo¬
ment he was seized with the strongest desire of
becoming acquainted with it. Here, indeed, was
4 a
DISS. IV., PART I.
1 Astronomia Instaurata, lib. i. cap. v.
602
PRELIMINARY DISSERTATIONS.
called into action a propensity nearly allied both
to the strength and the weakness of the mind of
this extraordinary man; the same that attached
him, on one hand, to the calculations of astrono¬
my, and, on the other, to the predictions of judi¬
cial astrology.
In yielding himself up, however, to his love
of astronomy, he found that he had several diffi¬
culties to overcome. He belonged to a class in
society elevated, in the opinion of that age, above
the pursuit of knowledge, and jealous of the pri¬
vilege of remaining ignorant with impunity.
Tycho was of a noble family in Denmark, so
that it required all the enthusiasm and firmness
inspired by the love of knowledge, to set him
above the prejudices of hereditary rank, and the
opposition of his relations. He succeeded, how¬
ever, in these objects, and also in obtaining the
patronage of the King of Denmark, by which he
was enabled to erect an observatory, and form an
establishment in the island of Huen, such as
had never yet been dedicated to astronomy.
The instruments were of far greater size, more
skilfully contrived, and more nicely divided,
than any that had yet been directed to the
heavens. By means of them, Tycho could mea¬
sure angles to ten seconds, which may be ac¬
counted sixty times the accuracy of the instru¬
ments of Ptolemy, or of any that had belonged
to the school of Alexandria.
Among the improvements which he made in
the art of astronomical observation, was that of
verifying the instruments, or determining their
errors by actual observation, instead of trusting,
as had been hitherto done, to the supposed infal¬
libility of the original construction.
One of the first objects to which the Danish
astronomer applied himself, was the formation
of a new catalogue of the fixed stars. That
which was begun by Hipparchus, and continued
by Ptolemy, did not give the places of the stars
with an accuracy nearly equal to that which the
new instruments were capable of reaching; and
it was, besides, desirable to know whether the
lapse of twelve centuries had produced any un¬
foreseen changes in the heavens.
The great difficulty in the execution of this
work arose from the want of a direct and easy
method of ascertaining the distance of one heav¬
enly body due east or west of another. The
distance north or south, either from one another
or from a fixed plane, that of the equator, was
easily determined by the common method of
meridian altitudes, the equator being a plane
which,, for any given place on the earth’s sur¬
face, retains always the same position. But no
plane extending from north to south, or passing
through the poles, retains a fixed position with
respect to an observer; and, therefore, the same
way of measuring distances from such a plane
cannot be applied. The natural substitute is
the measure of time; the interval between the
passage of two stars over the meridian, bear¬
ing the same proportion to twenty-four hours,
that the arch which measures their distance
perpendicular to the meridian, or their dif¬
ference of right ascension, does to four right
angles.
An accurate measure of time, therefore, would
answer the purpose; but such a measure no more
existed in the age of Tycho, than it had done in
the days of Hipparchus or Ptolemy. These an¬
cient astronomers determined the longitude of
the fixed stars by referring their places to those
of the moon, the longitude of which, for a given
time, was known from the theory of her motions.
Thus they were forced to depend on the most
irregular of all the bodies in the heavens, for
ascertaining the positions of the most fixed,
those which ought to have been the basis of the
former, and of so many other determinations.
Tycho made use of the planet Venus instead of
the moon; and his method, though more tedious,
was more accurate than that of the Greek astron¬
omers. His catalogue contained the places of
777 fixed stars.
The irregularities of the moon’s motions were
his next subjects of inquiry. The ancients had
discovered the inequality of that planet depend¬
ing on the eccentricity of the orbit, the same
which is now called the equation of the centre.1
Ptolemy had added the knowledge of another
1 The allowance made for any such equality, when the place of a planet is to be computed for a given time, is called an
equation in the language of astronomy.
DISSERTATION FOURTH. 603
inequality in the moon’s motion, to which the
name of the evection has been given, amounting
to an increase of the former equation at the
quarters, and a diminution of it at the times of
new and full moon. Tycho discovered another
inequality, which is greatest at the octants, and
depends on the difference between the longitude
of the moon and that of the sun. A fourth irre¬
gularity to which the moon’s motion is subject,
depending wholly on the sun’s place, was known
to Tycho, hut included among the sun’s equa¬
tions. Besides, these observations made him
acquainted with the changes in the inclination
of the plane of the moon’s orbit; and, lastly,
with the irregular motion of the nodes, which,
instead of being always retrograde at the same
rate, are subject to change that rate, and even
to become progressive according to their situa¬
tion in respect of the sun. These are the only
inequalities of the moon’s motion known before
the theory of Gravitation, and, except the first
two, are all the discoveries of Tycho.
The atmospherical refraction, by which the
heavenly bodies are made to appear more ele¬
vated above the horizon than they really are,
was suspected before the time of this astrono¬
mer, but not known with certainty to exist.
He first became acquainted with it by finding
that the latitude of his observatory, as deter¬
mined from observations at the solstices, and
from observations of the greatest and least alti¬
tudes of the circumpolar stars, always differed
about four minutes. The effect of refraction he
supposed to be 34' at the horizon, and to dimi¬
nish from thence upward, till at 45° it ceased
altogether. This last supposition is erroneous,
but at 45* the refraction is less than 1', and pro¬
bably was not sensible in the altitudes measured
with his instruments, or not distinguishable
from the errors of observation. An instrument
which he contrived on purpose to make the re¬
fraction distinctly visible, shows the scale on
which his observatory was furnished. It was
an equatorial circle of ten feet diameter, turn¬
ing on an axis parallel to that of the earth. With
the sights of this equatorial he followed the sun
on the day of the summer solstice, and found,
that as it descended towards the horizon, it rose
above the plane of the instrument. At its set¬
ting, the sun was raised above the horizon by
more than its own diameter.
The comet of 1570 was carefully observed by
Tycho, and gave rise to a new theory of those
bodies. He found the horizontal parallax to be
20', so that the comet was nearly three times as
far off as the moon. He considered comets,
therefore, as bodies placed far beyond the reach
of our atmosphere, and moving round the sun.
This was a severe blow to the Physics of Aris¬
totle, which regarded comets as meteors gener¬
ated in the atmosphere. His observation of the
new star in 1572 was no less hostile to the argu¬
ment of the same philosopher, which maintained,
that the heavens are a region in which there is
neither generation nor corruption, and in which
existence has neither a beginning nor an end.
Yet Tycho, with this knowledge of astronomy,
and after having made observations more nume¬
rous and accurate than all the astronomers who
went before him, continued to reject the system
of Copernicus, and to deny the motion of the
earth. He was, however, convinced that the
earth is not the centre about which the planets
revolve; for he had himself observed Mars,
when in opposition, to he nearer to the earth
than the earth was to the sun; so that, if the
planets were ranged as in the Ptolemaic system,
the orbit of Mars must have been within the
orbit of the sun. He therefore imagined the
system still known by his name, according to
which the sun moves round the earth, and is at
the same time the centre of the planetary mo¬
tions. It cannot he denied, that the phenomena
purely astronomical may he accounted for on
this hypothesis, and that the objections to it are
rather derived from physical and mechanical
considerations than from the appearances them¬
selves. It is simpler than the Ptolemaic sys¬
tem, and free from its inconsistencies; hut it is
more complex than the Copernican, and in no
respect affords a better explanation of the phe¬
nomena. The true place of the Tychonic sys¬
tem is between the two former; an advance be¬
yond the one, and a step short of the other; and
such, if the progress of discovery were always
perfectly regular, is the place which it would
have occupied in the history of the science. If
Tycho had lived before Copernicus, his system
604
PRELIMINARY DISSERTATIONS.
would have been a step in the advancement of
knowledge; coming after him, it was a step
backward.
It is not to his credit as a philosopher to have
made this retrograde movement, yet he is not
altogether without apology. The physical argu¬
ments in favour of the Copernican system,
founded on the incongruity of supposing the
greater body to move round the smaller, might
not he supposed to have much weight, in an age
when the equality of action and reaction was
unknown, and when it was not clearly under¬
stood that the sun and the planets act at all on
one another. The arguments which seem, in
the judgment of Tycho, to have balanced the
simplicity of the Copernican system, were found¬
ed on certain texts of Scripture, and on the
difficulty of reconciling the motion of the earth
with the sensations which we experience at its
surface, or the phenomena which we observe,
the same, in all respects, as if the earth were
at rest. The experiments and reasonings of
Galileo had not yet instructed men in the inertia
of matter, or in the composition of motion; and
the followers of Copernicus reasoned on prin¬
ciples which they held in common with their
adversaries. A hall, it was said hy the latter,
dropt from the mast-head of a ship under sail,
does not fall at the foot of the mast, hut some¬
what behind it; and in the same manner, a
stone dropt from a high tower would not fall,
on the supposition of the earth’s motion, at the
bottom of the tower, hut to the west of it, the
earth, during its fall, having gone eastward from
under it. The followers of Copernicus were
not yet provided with the true answer to this
objection, viz. that the hall does actually fall at
the bottom of the mast. It was admitted that
it must fall behind it, because the hall was no
part of the ship, and that the motion forward
was not natural, either to the ship or to the
hall. The stone, on the other hand, let fall
from the top of the tower, was a part of the
earth, and therefore the diurnal and annual
revolutions which were natural to the earth
were also natural to the stone; the stone would
therefore retain the same motion with the tower,
and strike the ground precisely at the bottom of it.
It must be confessed, that neither of these
logicians had yet thoroughly awakened from the
dreams of the Aristotelian metaphysics; hut
men were now in possession of the truth, which
was finally to break the spell, and set the mind
free from the fetters of prejudice and authority.
Another charge, against which it is more difficult
to defend Tycho, is his belief in the predictions of
astrology. He even wrote a treatise in defence of
this imaginary art, and regulated his conduct
continually hy its precepts. Credulity, so un¬
worthy of a man deeply versed in real science, is
certainly to he set down less to his own account
than to that of the age in which he lived.
3. KEPLER AND GALILEO.
Kepler followed Tycho, and in his hands
astronomy underwent a change only second to
that which it had undergone in the hands of
Copernicus. He was horn in 1571. He early
applied himself to study and observe the heavens,
and was soon distinguished as an inventor. He
began with taking a more accurate view of
astronomical refraction than had yet been done,
and he appears to have been the first who con¬
ceived that there must he a certain fixed law
which determined the quantity of it, correspond¬
ing to every altitude, from the horizon to the
zenith. The application of the principles of op¬
tics to astronomy, and the accurate distinction
between the optical and real inequalities of the
planets, are the work of the same astronomer.
It was by the views thus presented that he was
led to the method of constructing and calculating
eclipses hy means of projections, without taking
into consideration the diurnal parallax. These
are valuable improvements, but they were, how¬
ever, obscured by the greatness of his future
discoveries.
The planes of the orbits of the planets were
naturally, in the Ptolemaic system, supposed to
pass through the earth; and the reformation of
Copernicus did not go so far as to change the
notions on that subject which had generally been
adopted. Kepler observed that the orbits of the
planets are in planes passing through the sun,
DISSERTATION FOURTH.
605
and that, of consequence, the lines of their
nodes all intersect in the centre of that lumi¬
nary. This discovery contributed essentially to
those which followed.
The oppositions of the planets, or their places
when they pass the meridian at midnight, offer
the most favourable opportunities for observing
them, both because they are at that time nearest
to the earth, and because their places seen from
thence are the same as if they were seen from the
sun. The true time of the opposition had how¬
ever been, till now, mistaken by astronomers,
who held it to be at the moment when the appa¬
rent place of the planet was opposite to the mean
place of the sun. It ought, however, to have
been, when the apparent places of both were op¬
posed to one another. This reformation was
proposed by Kepler, and, though strenuously
resisted by Tycho, was finally received.
Having undertaken to examine the orbit of
Mars, in which the irregularities are most con¬
siderable, Kepler discovered, by comparing to¬
gether seven oppositions of that planet, that its
orbit is elliptical; that the sun is placed in one
of the foci; and that there is no point round
which the angular motion is uniform. In the
pursuit of this inquiry he found that the same
thing is true of the earth’s orbit round the sun :
hence by analogy it was reasonable to think,
that all the planetary orbits are elliptical, hav¬
ing the sun in their common focus.
The industry and patience of Kepler, in this
investigation, were not less remarkable than his
ingenuity and invention. Logarithms were not
yet known, so that arithmetical computation,
when pushed to great accuracy, was carried on
at a vast expense of time and labour. In the
calculation of every opposition of Mars, the
work filled ten folio pages, and Kepler repeated
each calculation ten times, so that the whole
work for each opposition extended to one hun¬
dred such pages: seven oppositions thus calcu¬
lated produced a large folio volume.
In these calculations the introduction of hy¬
potheses was unavoidable, and Kepler’s candour
in rejecting them, whenever they appeared er¬
roneous, without any other regret than for the
time which they had cost him, cannot be suffi¬
ciently admired. He began with hypothesis,
and ended with rejecting every thing hypotheti¬
cal. In this great astronomer we find genius,
industry, and candour, all uniting together as
instruments of investigation.
Though the angular motion of the planet was
not found to be uniform, it was discovered that
a very simple law connected that motion with
the rectilineal distance from the sun, the former
being everywhere inversely as the square of
the latter; and hence it was easy to prove, that
the area described by the line drawn from the
planet to the sun increased at a uniform rate,
and, therefore, that any two such areas were
proportional to the times in which they were
described. The picture presented of the heavens
was thus, for the first time, cleared of every
thing hypothetical.
The same astronomer was perhaps the first
person who conceived that there must be always
a law capable of being expressed by arithmetic
or geometry, which connects such phenomena
as have a physical dependence on one another.
His conviction of this truth, and the delight
which he appears to have experienced in the
contemplation of such laws, led him to seek,
with great eagerness, for the relation between
the periodical times of the planets and their
distances from the sun. He seems, indeed, to
have looked towards this object with such ear¬
nestness, that, while it was not attained, he re¬
garded all his other discoveries as incomplete.
He at last found, infinitely to his satisfaction,
that in any two planets the squares of the times
of the revolution are as the cubes of their mean
distances from the sun. This beautiful and
simple law had a value beyond what Kepler
could possibly conceive ; yet a sort of scientific
instinct instructed him in its great importance.
He has marked the year and the day when it
became known to him; it was on the 8th of
May 1618; and perhaps philosophers will agree
that there are few days in the scientific history
of the world which deserve so well to be remem¬
bered.
These great discoveries, however, were not
much attended to by the astronomers of that
period, or by those who immediately followed.
They were but little considered by Gassendi,—
they were undervalued by Riccioli,—and were
606
PRELIMINARY DISSERTATIONS.
never mentioned by Descartes. It was an ho¬
nour reserved for Newton to estimate them at
their true value.
Indeed the discoveries of Kepler were at first
so far from being duly appreciated, that they
were objected to, not for being false, but for of¬
fering to astronomers, in the calculation of the
place of a planet in its orbit, a problem too dif¬
ficult to be resolved by elementary geometry.
To cut the area of a semi-ellipsis in a given ratio
by a line drawn through the focus, is the geo¬
metrical problem into which he showed that the
above inquiry ultimately resolved. As if he had
been answerable for the proceedings of nature,
the difficulty of this question was considered as
an argument against his theory, and he himself
seems somewhat to have felt it as an objection,
especially when he found that the best solution
he could obtain was no more than an approxi¬
mation. With all his power of invention, Kep¬
ler was a mathematician inferior to many of
that period; and though he displayed great abi¬
lity in the management of this difficult investi¬
gation, his solution fell very far short of the
simplicity which it was afterwards found ca¬
pable of attaining.
In addition to all this, he rendered another
very important service to the science of astro¬
nomy and to the system of Copernicus. Coper¬
nicus, it has been already mentioned, had sup¬
posed that a force was necessary to enable the
earth to preserve the parallelism of its axis du¬
ring its revolution round the sun. He imagined,
therefore, that a third motion belonged to the
earth, and that, besides turning on its axis and
revolving round the sun, it had another move¬
ment by which its axis was preserved always
equally inclined to the ecliptic. Kepler was the
first to observe that this third motion was quite
superfluous, and that the parallelism of the
earth’s axis, in order to be preserved, required
nothing but the absence of all force, as it neces¬
sarily proceeded from the inertia of matter, and
its tendency to persevere in a state of uniform
motion. Kepler had a clear idea of the inertia
of body; he was the first who employed the
term; and, considering all motion as naturally
rectilineal, he concluded that when a body moves
in a curve, it is drawn or forced out of the
straight line by the action of some cause, not
residing in itself. Thus he prepared the way
for physical astronomy, and in these ideas he
was earlier than Descartes.
The discoveries of Kepler were secrets extort¬
ed from nature by the most profound and labo¬
rious research. The astronomical discoveries of
Galileo, more brilliant and imposing, were made
at a far less expense of intellectual labour. By
this it is not meant to say that Galileo did not
possess, and did not exert, intellectual powers of
the very highest order; but it was less in his
astronomical discoveries that he had occasion to
exert them, than in those which concerned the
theory of motion. The telescope, turned to the
heavens for the first time, in the hands of a man
far inferior to the Italian philosopher, must have
unfolded a series of wonders to astonish and
delight the world.
It was in the year 1609 that the news of a
discovery, made in Holland, reached Galileo,
viz. that two glasses had been so combined as
greatly to magnify the objects seen through them.
More was not told, and more was not necessary
to awaken a mind abundantly alive to all that
interested the progress either of science or of art.
Galileo applied himself to try various combina¬
tions of lenses, and he quickly fell on one which
made objects appear greater than when seen by
the naked eye, in the proportion of three to one.
He soon improved on this construction, and
found one which magnified thirty-two times,
nearly as much as the kind of telescope he used
is capable of. That telescope was formed of two
lenses; the lens next the object convex, the other
concave; the objects were presented upright,
and magnified in their lineal dimensions in the
proportion just assigned.
Having tried the effect of this combination on
terrestrial objects, he next directed it to the
moon. What the telescope discovers on the
ever-varying face of that luminary, is now well
known, and needs not to be described; but the
sensations which the view must have communi¬
cated to the philosopher who first beheld it, may
be conceived more easily than expressed. To
the immediate impression which they made upon
the sense, to the wonder they excited in all who
saw them, was added the proof, which, on re-
DISSERTATION FOURTH.
607
flection, they afforded, of the close resemblance
between the earth and the celestial bodies, whose
divine nature had been so long and so errone¬
ously contrasted with the ponderous and opaque
substance of our globe. The earth and the planets
were now proved to he bodies of the same kind,
and views were entertained of the universe,
more suitable to the simplicity and the magni¬
ficence of nature.
When the same philosopher directed his tele¬
scope to the' fixed stars, if he was disappointed
at finding their magnitudes not increased, he was
astonished and delighted to find them multiplied
in so great a degree, and such numbers brought
into view, which were invisible to the naked eye.
In Jupiter he perceived a large disk, approach¬
ing in size to the moon. Near it, as he saw it
for the first time, were three luminous points
ranged in a straight line, two of them on one
side of the planet, and one on the other. This
occasioned no surprise, for they might he small
stars not visible to the naked eye, such as he
had already discovered in great numbers. By
observing them, however, night after night, he
found these small stars to be four in number,
and to he moons or satellites, accompanying
Jupiter, and revolving round him, as the moon
revolves round the earth.
The eclipses of these satellites, their conjunc¬
tions with the planet, their disappearance behind
his disk, their periodical revolutions, and the
very problem of distinguishing them from one
another, offered, to an astronomer, a series of
new and interesting observations.
In Saturn he saw one large disk, with two
smaller ones very near it, and diametrically op¬
posite, and always seen in the same places; but
more powerful telescopes were required before
these appearances could he interpreted.
The horned figure of Venus, and the gibbosi¬
ty of Mars, added to the evidence of the Coper-
nican system, and verified the conjectures of its
author, who had ventured to say, that, if the
sense of sight were sufficiently powerful, we
should see Mercury and Venus exhibiting phases
similar to those of the moon.
The spots of the sun derived an interest from
their contrast with the luminous disk over which
they seemed to pass. They were found to have
such regular periods of return as could he de¬
rived only from the motion of the disk itself;
and thus the sun’s revolution on his axis, and
the time of that revolution, were clearly ascer¬
tained.
This succession of noble discoveries, the most
splendid, probably, which it ever fell to the lot
of one individual to make, in a better age would
have entitled its author to the admiration and
gratitude of the whole scientific world, hut was
now viewed from several quarters with suspicion
and jealousy. The ability and success with
which Galileo had laboured to overturn the doc¬
trines of Aristotle and the schoolmen, as well as
to establish the motion of the earth and the im¬
mobility of the sun, had excited many enemies.
There are always great numbers who, from
habit, indolence, or fear, are the determined sup¬
porters of what is established, whether in prac¬
tice-or in opinion. To these the constitution of
the universities of Europe, so entirely subjected
to the church, had added a numerous and learn¬
ed phalanx, interested to preserve the old sys¬
tems, and to resist all innovations which could
endanger their authority or their repose. The
church itself was roused to action, by reflecting
that it had staked the infallibility of its judg¬
ments on the truth of the very opinions which
were now in danger of being overthrown. Thus
was formed a vast combination of men, not very
scrupulous about the means which they used to
annoy their adversaries : the power was entirely
in their hands, and there was nothing hut truth
and reason to be opposed to it.
The system of Copernicus, however, while it
remained obscure, and known only to astrono¬
mers, created no alarm in the church. It had
even been ushered into the world at the solici¬
tation of a cardinal, and under the patronage of
the Pope; but when it became more popular,
when the ability and acuteness of Galileo were
enlisted on its side, the consequences became
alarming; and it was determined to silence by
force an adversary who could not he put down
by argument. His Dialogues contained a full
exposition of the evidence of the earth’s motion,
and set forth the errors of the old, as well as the
discoveries of the new philosophy, with great
force of reasoning, and with the charms of the
608
PRELIMINARY DISSERTATIONS.
most lively eloquence. They are written, in¬
deed, with such singular felicity, that one reads
them at the present day, when the truths con¬
tained in them are known and admitted, with
all the delight of novelty, and feels one’s self
carried hack to the period when the telescope
was first directed to the heavens, and when the
earth’s motion, with all its train of consequences,
was proved for the first time. The author of
such a work could not be forgiven. Galileo, ac¬
cordingly, was twice brought before the Inqui¬
sition. The first time a council of seven car¬
dinals pronounced a sentence which, for the
sake of those disposed to believe that power can
subdue truth, ought never to be forgotten:
“ That to maintain the sun to be immovable,
and without local motion, in the centre of the
world, is an absurd proposition, false in philo¬
sophy, heretical in religion, and contrary to the
testimony of Scripture. That it is equally ab¬
surd and false in philosophy to assert that the
earth is not immovable in the centre of the
world, and, considered theologically, equally er¬
roneous and heretical.”
These seven theologians might think them¬
selves officially entitled to decide on what was
heretical or orthodox in faith; but, that they
should determine what was true or false in phi¬
losophy,' was an insolent invasion of a territory
into which they had no right to enter, and is a
proof how ready men are to suppose themselves
wise, merely because they happen to be power¬
ful. At this time a promise was extorted from
Galileo, that he would not teach the doctrine of
the earth’s motion, either by speaking or by
writing. To this promise he did not conform.
His third dialogue, published, though not till long
afterwards, contained such a full display of the
beauty and simplicity of the new system, and such
an exposure of the inconsistencies of Ptolemy and
Tycho, as completed the triumph of Copernicus.
In the year 1633, Galileo, now seventy years
old, being brought before the Inquisition, was
forced solemnly to disavow his belief in the
earth’s motion; and condemned to perpetual
imprisonment, though the sentence was after¬
wards mitigated, and he was allowed to return
to Florence.1 The Court of Rome was very
careful to publish this second recantation all
over Europe, thinking, no doubt, that it was ad¬
ministering a complete antidote to the belief ot
the Copernican system. The sentence, indeed,
appears to have pressed very heavily on Galileo’s
mind, and he never afterwards either talked or
wrote on the subject of astronomy. Such was
the triumph of his enemies, on whom ample
vengeance would have long ago been executed,
if the indignation and contempt of posterity
could reach the mansions of the dead.
Conduct like this, in men professing to be the
ministers of religion and the guardians of truth,
can give rise to none but the most painful re¬
flections. That an aged philosopher should be
forced, laying his hand on the sacred Scriptures,
to disavow opinions which he could not cease to
hold without ceasing to think, was as much a
profanation of religion as a violation of truth
and justice. Was it the act of hypocrites, who
considered religion as a state engine, or of bigots,
long trained in the art of believing without evi¬
dence, or even in opposition to it ? These ques¬
tions it were unnecessary to resolve; but one
conclusion cannot be denied, that the indiscreet
defenders of religion have often proved its worst
enemies.
At length, however, by the improvements,
the discoveries, and the reasonings, first of Kep¬
ler, and then of Galileo, the evidence of the Co¬
pernican system was fully developed, and no¬
thing was wanting to its complete establishment
but time sufficient to allow opinion to come gra¬
dually round, and to give men an opportunity
of studying the arguments placed before them.
Of the adherents of the old system, many had
been too long habituated to it to change their
views; but as they disappeared from the scene,
they were replaced by young astronomers, not
under the influence of the same prejudices, and
eager to follow doctrines which seemed to offer
so many new subjects of investigation. In the
1 He was thrown into prison previously to his trial, and attempts were made to render him obnoxious to the people.
From the text of a priest who preached against him, we may judge of the wit and the sense with which this persecution was
conducted : Viri Ga/ilcei, quid statis in ccelum suspicientes f
DISSERTATION FOURTH.
609
next generation the systems of Ptolemy and
Tyclio had no followers.
It was not astronomy alone which was be¬
nefited by this revolution, and the discussions
to which it had given rise. A new light, as al¬
ready remarked, was thrown on the physical
world, and the curtain was drawn aside which
had so long concealed the great experiment, by
which nature herself manifests, at every in¬
stant, the inertia of body, and the composition
of forces. To reconcile the real motion of the
earth with its appearance of rest and with our
feeling of its immobility, required such an exa¬
mination of the nature of motion as discovered,
if not its essence, at least its most general and
fundamental properties. The whole science of
rational mechanics profited, therefore, essential¬
ly by the discovery of the earth’s motion.
A great harrier to philosophic improvement
had arisen from the separation so early made,
and so strenuously supported in the ancient
systems, between terrestrial and celestial sub¬
stances, and between the laws which regulate
motion on the earth and in the heavens. This
barrier was now entirely removed; the earth
was elevated to the rank of a planet; the planets
were reduced to the condition of earths; and by
this mutual approach, the same rules of inter¬
pretation became applicable to the phenomena
of both. Principles derived from experiments
on the earth, became guides for the analysis of
the heavens; and men were now in a situation
to undertake investigations, which the most
hardy adventurer in science could not before have
dared to imagine. Philosophers had ascended
to the knowledge of the affinities which pervade
all nature, and which mark so strongly both
the wisdom and unity of its author.
The light thus struck out darted its rays into
regions the most remote from physical inquiry.
When men saw opinions entirely disproved,
which were sanctioned by all antiquity, and by
the authority of the greatest names, they began
to have different notions of the rules of evi¬
dence, of the principles of philosophic inquiry,
and of the nature of the mind itself. It ap¬
peared that science was destined to be continu¬
ally progressive; provided it was taken for
an inviolable maxim, that all opinion must
be ultimately amenable to experience and obser¬
vation.
It Avas no slight addition to all these advan¬
tages, that, in consequence of the discussions
from which Galileo had unhappily been so great
a sufferer, the line Avas at length definitely drawn
which was to separate the provinces of faith and
philosophy from one another. It became a prin¬
ciple, recognised on all hands, that revelation,
not being intended to inform men of those
things which the unassisted powers of their own
understanding Avould in time be able to discover,
had, in speaking of such matters, employed the
language and adopted the opinions of the times;
and thus the magic circle, by which the priest
had endeavoured to circumscribe the inquiries
of the philosopher, entirely disappeared. The
reformation in religion which was taking place
about the same time, and giving such energy to
the human mind, contributed to render this
emancipation more complete, and to reduce the
exorbitant pretensions of the Romish church.
The prohibition against believing in the true
system of the world either ceased altogether, or
was reduced to an empty form, by which the
affectation of infallibility still preserves the me¬
mory of its errors.1
4. DESCARTES, HUYGENS, &c.
Descartes flourished about this period, and or who formed the great and philosophic con-
has the merit of being the first who undertook ception of reducing all the phenomena of the
to give an explanation of the celestial motions, universe to the same laAv. The time was now
tVi. jT^e fathe.rs Yil0 have’ lvith 80 much abilit^ commented on the Principia of Newton, have prefixed to the
t ira book this remarkable declaration: “ Newtonus in hoc tertio libro telluris motse hypothesin assumit. Auctoris pro-
positiones ahter explicari non poterant, nisi eadem facta hypothesi. Hinc alienam coacti sumus gerere personam. Ceterum
a ls a summ™ Pantifieibw erntro, tellnris motum Decretis nos olsequi prqfitemur.” There is an archness in the last sentence,
at looks as it the authors wanted to convey meanings that would differ according to the orthodoxy of the readers.
DISS. IV., PART I. 4 H
610
PRELIMINARY DISSERTATIONS,
arrived when, from the acknowledged assimila¬
tion of the planets to the earth, this might he
undertaken with some reasonable prospect of
success. No such attempt had hitherto been
made, unless the crystalline spheres or homo¬
centric orbs of the ancients are to he considered
in that light. The conjectures of Kepler about
a kind of animation, and of organic structure,
which pervaded the planetary regions, were too
vague and indefinite, and too little analogous to
any thing known on the earth, to he entitled to
the name of a theory. To Descartes, therefore,
belongs the honour of being the first who ven¬
tured on the solution of the most arduous pro¬
blem which the material world offers to the con¬
sideration of philosophy. For this solution he
sought no other data than matter and motion,
and with them alone proposed to explain the
structure and constitution of the universe. The
matter which he required, too, was of the
simplest kind, possessing no properties but ex¬
tension, impenetrability} and inertia. It was
matter in the abstract, without any of its pecu¬
liar or distinguishing characters. To explain
these characters was indeed a part of the task
which he proposed to himself; and thus, by the
simplicity of his assumptions, he added infinite¬
ly to the difficulty of the problem which he un¬
dertook to resolve.
The matter thus constituted was supposed to
fill all space, and its parts, both great and small,
to he endued with motion in an infinite variety
of directions. From the combination of these,
the rectilineal motion of the parts became im¬
possible ; the atoms or particles of matter were
continually diverted from the lines in which
they had begun to move; so that circular mo¬
tion and centrifugal force originated from their
action on one another. Thus matter came to
he formed into a multitude of vortices, differing
in extent, in velocity, and in density; the more
subtile parts constituting the real vortex, in which
the denser bodies float, and by which they are
pressed, though not equally, on all sides.
Thus the universe consists of a multitude of
vortices, which limit and circumscribe one ano¬
ther. The earth and the planets are bodies car¬
ried round in the great vortex of the solar sys¬
tem ; and by the pressure of the subtile matter.
which circulates with great rapidity and great
centrifugal force, the denser bodies, which have
less rapidity and less centrifugal force, are
forced down toward the sun, the centre of the
vortex. In like manner, each planet is itself
the centre of a smaller vortex, by the subtile
matter of which the phenomena of gravity are
produced, just as with us at the surface of the
earth.
The gradation of smaller vortices may be
continued in the same manner, to explain the
cohesion of the grosser bodies, and their other
sensible qualities. But I forbear to enter into
the detail of a system which is now entirely ex¬
ploded, and so inconsistent with the views of
nature which have become familiar to every one,
that such details can hardly be listened to with
patience. Indeed the theory of vortices did not
explain a single phenomenon in a satisfactory
manner, nor is there a truth of any kind which
has been brought to light by means of it. None
of the peculiar properties of the planetary orbits
were taken into the account; none of the laws
of Kepler were considered; nor was any expla¬
nation given of those laws, more than of any
other that might be imagined. The philosophy
of Descartes could explain all things equally
well, and might have been accommodated to
the systems of Ptolemy or Tycho, just as well
as to that of Copernicus. It forms, therefore,
no link in the chain of physical discovery; it
served the cause of truth only by exploding
errors more pernicious than its own; by ex¬
hausting a source of deception, which might
have misled other adventurers in science; and
by leaving a striking proof how little advance¬
ment can be made in philosophy by pursuing
any path but that of experiment and induction.
Descartes was, nevertheless, a man of great
genius, a deep thinker, of enlarged views, and
entirely superior to prejudice. Yet, in as far as
the explanation of astronomical phenomena is
concerned, (and it was his main object) he did
good only by showing in what quarter the at¬
tempt could not be made with success; he was
the forlorn hope of the new philosophy, and must
be sacrificed for the benefit of those who were
to follow.
Gassendi, the contemporary and countryman
DISSERTATION FOURTH.
611
of Descartes, possessed great learning, with a
very clear and sound understanding. He was
a good observer, and an enlightened advocate of
the Copernican system. He explained, in a very
satisfactory manner, the connection between the
laws of motion and the motion of the earth, and
made experiments to show, that a body carried
along by another acquires a motion which re¬
mains after it has ceased to be so carried. Gas¬
sendi first observed the transit of a planet over
the disk of the sun,—that of Mercury, in 1631.
Kepler had predicted this transit, hut did not
live to enjoy a spectacle which afforded so satis¬
factory a proof of the truth of his system, and
of the accuracy of his astronomical tables.
The first transit of Venus which was observed,
happened a few years later, in 1639, when it
was seen in England by Horrox and his friend
Crabtree, and by them only. Horrox, who was
a young man of great genius, had himself cal¬
culated the transit, and foretold the time very
accurately, though the astronomical tables of
that day gave different results; and those of
Kepler, in which he confided the most, Avere,
in this instance, considerably in error. Horrox
has also the merit of being among the first who
rightly appreciated the discoveries of the astron¬
omer just named. He had devoted much time
to astronomical observation, and, though he died
very young, he left behind him some prepara¬
tions for computing tables of the moon, on a
principle which was new, and which Newton
himself thought worthy of being adopted in his
theory of the inequalities of that planet.
The first complete system of astronomy in
which the elliptic orbits were introduced, was
the Astronomia Philolaica of Bullialdus, (Boul-
liau) published in 1645. They were intro¬
duced, however, with such hypothetical addi¬
tions, as show that the idea of a centre of uni¬
form motion had not yet entirely disappeared.
It is an idea, indeed, which gives considerable
relief to the imagination, and it besides leads to
methods of calculation more simple than the
true theory, and Bullialdus may have flattered
himself that they were sufficiently exact. He
conceives the elliptic orbit as a section of an
oblique cone, the axis of which passes through
the superior focus of the ellipse, while the planet
mo\res in its circumference in such a manner,
that a plane passing through it and through the
axis shall he carried round with a uniform an¬
gular velocity. It is plain that the cone and its
axis are mere fictions, arbitrarily assumed, and
not even possessing the advantage of simplicity.
The author himself departs from this hypothe¬
sis, and calculates the places of a planet, on the
supposition that it moves in the circumference
of an epicycle, and the epicycle in the circum¬
ference of an eccentric deferent, both angular
motions being uniform, that of the planet in the
epicycle being retrograde, and double the other.
The figure thus described may he shoAvn to he
an ellipse, hut the line drawn from the planet
to the focus does not cut off areas proportional
to the time.
An hypothesis advanced by Ward, bishop of
Salisbury, was simpler and more accurate than
that of the French astronomer. According to
it, the line drawn from a planet to the superior
focus of its elliptic orbit, turns with a uniform
angular Arelocity round that point. In orbits of
small eccentricity, this is nearly true, and al¬
most coincides in such cases with Kepler’s prin¬
ciple of the uniform description of areas. Dr
Ward, however, did not consider the matter in
that light; he assumed his hypothesis as true,
guided, it would seem, by nothing but the opin¬
ion, that a centre of uniform motion must some-
where exist, and pleased with the simplicity thus
introduced into astronomical calculation. It is
indeed remarkable, as Montucla has observed,
how little the most enlightened astronomers
of that time seem to have studied or under¬
stood the laws discovered by Kepler. Riccioli,
of whom we are just about to speak, enumerates
all the suppositions that had been laid down
concerning the velocities of the planets, but
makes no mention of their describing equal areas
in equal times round the sun. Even Cassini,
great as he was in astronomy, cannot he entire¬
ly exempted from this censure.
Riccioli, a good observer, and a learned and
diligent compiler, has collected all that was
known in astronomy about the middle of the
seventeenth century, in a voluminous work, the
New Almagest. Without much originality, he
was a very useful author, having had, as the
612
PRELIMINARY DISSERTATIONS.
historian of astronomy remarks, the courage and
the industry to read, to know, and to abridge
every thing. He was, nevertheless, an enemy
to the Copernican system, and has the discredit
of having measured the evidence for and against
that system, not by the weight, but by the num¬
ber of the arguments. The pains which he took
to prop the falling edifice of deferents and epi¬
cycles, added to his misapprehending and depre¬
ciating the discoveries of Kepler, subject him to
the reproach of having neither the genius to dis¬
cover truth, nor the good sense to distinguish it
when discovered. He was, however, a priest
and a Jesuit; he had seen the fate of Galileo;
and his errors may have arisen from want of
courage, more than from want of discernment.
Of the phenomena which the telescope in the
hands of Galileo had made known, the most pa¬
radoxical were those exhibited by Saturn; some¬
times attended by two globes, one on each side,
without any relative motion, but which would,
at stated times, disappear for a while, and leave
the planet single, like the other heavenly bodies.
Nearly forty years had elapsed, without any fur¬
ther insight into these mysterious appearances,
when Huygens began to examine the heavens
with telescopes of his own construction, better
and more powerful than any which had yet been
employed. The two globes that had appeared
insulated, were now seen connected by a circu¬
lar and luminous belt, going quite round the
planet. At last, it was found that all these ap¬
pearances resulted from a broad ring surround¬
ing Saturn, and seen obliquely from the earth.
The gradual manner in which this truth unfold¬
ed itself is very interesting, and has been given
with the detail that it deserves by Huygens, in
his Systema Saturnium.
The attention which Huygens had paid to the
ring of Saturn, led him to the discovery of a
satellite of the same planet. His telescopes
were not powerful enough to discover more of
them than one; he believed, indeed, that there
were no more, and that the number of the
planets now discovered was complete. The rea¬
soning by which he convinced himself, is a proof
how slowly men are cured of their prejudices,
even with the best talents and the best informa¬
tion. The planets, primary and secondary, thus
made up twelve, the double of six, the first of
the perfect numbers. In 1671, however, Cassini
discovered another satellite, and afterwards three
more, making five in all, which the more perfect
telescopes of Hr Herschell have lately augment¬
ed to seven.
To the genius of Huygens astronomy is in¬
debted for an addition to its apparatus, hardly
less essential than the quadrant and the tele¬
scope. An accurate measure of time is of use
even in the ordinary business of life, but to the
astronomer is infinitely valuable. The dates of
his observations, and an accurate estimate of the
time elapsed between them, are necessary, in or¬
der to make them lead to any useful conse¬
quences. Besides this, the only way of measur¬
ing with accuracy those arches in the heavens,
which extend from east to west, or which are
parallel to the equator, depends on the earth’s
rotation; because such an arch bears the same
proportion to the entire circumference of a cir¬
cle, that the time of its passage under the meri¬
dian bears to an entire day. The reckoning of
time thus furnishes the best measure of position,
as determined by arches parallel to the equator,
whether on the earth or in the heavens.
Though the pendulum afforded a measure of
time, in itself of the greatest exactness, the
means of continuing its motion, without disturb¬
ing the time of its vibrations, was yet requir¬
ed to be found; and this, by means of the clock,
Huygens contrived most ingeniously to effect.
Each vibration of the pendulum, by means of an
arm at right angles to it, allows the tooth of a
wheel to escape, the wheel being put in motion
by a weight. The wheel is so contrived, that
the force with which it acts is just sufficient to
restore to the pendulum the motion which it had
lost by the resistance of the air, and the friction
at the centre of motion. Thus the motion of
the clock is continued without any diminution
of its uniformity, for any length of time.
The telescope had not yet served astronomy
in all the capacities in which it could be useful.
Huygens, of whose inventive genius the history
of science has so much to record, applied it to
the measurement of small angles, forming it into
the instrument which has since been called a mi¬
crometer. By introducing into the focus of the
DISSERTATION FOURTH.
613
telescope a round aperture of a given size, he
contrived to measure the angle which that aper¬
ture subtended to the eye, by observing the time
that a star placed near the equator required to
traverse it. When the angle subtended by any
other object in the telescope was to he measured,
he introduced into the focus a thin piece of metal,
just sufficient to cover the object in the focus.
The proportion of the breadth of this plate to
the diametei; of the aperture formerly measured,
gave the angle subtended by the image in the
focus of the telescope. This contrivance is de¬
scribed in the Systema Saturnium, at the end.
The telescope has further contributed materi¬
ally to the accuracy of astronomical observation,
by its application to instruments used for measur¬
ing, not merely small angles, but angles of any
magnitude whatever. The telescope here comes
in place of the plain sights with which the index
or allidad of an instrument used to be directed
to an object, and this substitution has been ac¬
companied with two advantages. The disk of a
star is never so well defined to the naked eye as
it is in the telescope. Besides, in using plain
sights, the eye adapts itself to the farther off of
the two, in order that its aperture may be dis¬
tinctly seen. Whenever this adjustment is made,
the object seen through the aperture necessarily
appears indistinct to the eye, which is then adapt¬
ed to a near object. This circumstance pro¬
duces an uncertainty in all such observations,
which, by the use of the telescope, is entirely
removed.
But the greatest advantage arises from the
magnifying power of the telescope, from which
it follows, that what is a mere point to the naked
eye, is an extended line which can be divided
into a great number of parts when seen through
the former. The best eye, when not aided by
glasses, is not able to perceive an object which
subtends an angle less than half a minute, or
thirty seconds. When the index of a quadrant,
therefore, is directed by the naked eye to any
point in the heavens, we cannot be sure that it
is nearer than half a minute on either side of
that point. But when we direct the axis of a
telescope, which magnifies thirty times, to the
same object, we are sure that it is within the
thirtieth part of half a minute, that is, within
one second of the point aimed at. Thus the
accuracy, cceteris paribus, is proportional to the
magnifying power.
The application of the telescope, however, to
astronomical instruments, was not introduced
without opposition. Hevelius of Dantzic, the
greatest observer who had been since Tycho
Brahe, who had furnished his observatory with
the best and largest instruments, and who was
familiar with the use of the telescope, strenu¬
ously maintained the superiority of the plain
sights. His principal argument was founded
on this,—that, in plain sights, the line of colli-
mation is determined in its position by two fixed
points at a considerable distance from one an¬
other, viz. the centres of the two apertures of
the sights, so that it remains invariable with
respect to the index.
In the case of the telescope there was one fixed
point, the intersection of the wires in the focus
of the eye-glass; but Hevelius did not think
that the other point, viz. the optical centre of
the object-glass, was equally well defined. This
doubt, however, might have been removed by a
direct appeal to experiment, or to angles actually
measured on the ground, first by an instrument,
and then by trigonometrical operations. From
thence it would soon have been discovered, that
the centre of a lens is in fact a point defined
more accurately than can be done by any me¬
chanical construction.
This method of deciding the question was not
resorted to. Hevelius and Hooke had a very
serious controversy concerning it, in which the
advantage remained with the latter. It should
have been observed, that the French astronomer
Picard was the first who employed instruments
furnished with telescopic sights, about the year
1665. It appears, however, that Gascoigne, an
English gentleman who fell at the battle of
Marston-moor in 1644, had anticipated the
French astronomer in this invention, but that
it had remained entirely unknown. He had also
anticipated the invention of the micrometer.
The vast additional accuracy thus given to in¬
struments formed a new era in the history of
astronomical observations.
Though Galileo had discovered the satellites
of Jupiter, their times of revolution, and even
614
PRELIMINARY DISSERTATIONS.
some of their inequalities, it yet remained to de¬
fine their motions with precision, and to con¬
struct tables for calculating their places. This
task was performed by the elder Cassini, who
was invited from Italy, his native country, b\
Louis the Fourteenth, and settled in France in
1669. His tables of the satellites had been pub¬
lished at Bologna three years before, and he
continued to improve them, by a series of ob¬
servations made in the observatory at Paris,
with great diligence and accuracy.
The theory of the motions of these small bodies
is a research of great difficulty, and had been
attempted by many astronomers before Cassini,
with very little success. The planes of the
orbits, their inclinations to the orbit of Jupiter,
and the lines in which they intersected that
orbit, were all to be determined, as well as the
times of revolution, and the distances of each
from its primary. Add to this, that it is only
in a few points of their orbits that they can be
observed with advantage. The best are at the
times of immersion into the shadow of Jupiter,
and emersion from it. The same excellent
astronomer discovered four satellites of Saturn,
in addition to that already observed by Huy¬
gens. He also discovered the rotation of Jupi¬
ter and of Mars upon their axes.
The constant attention bestowed on the eclip¬
ses of the satellites of Jupiter, made an inequa¬
lity he remarked in the periods of their return,
which seemed to depend on the position of the
earth relatively to Jupiter and the sun, and not,
as the inequalities of that sort might have been
expected to do, on the place of Jupiter in his
orbit. From the opposition of Jupiter to the
sun, till the conjunction, it was found that the
observed emersion of the satellites from the
shadow fell more and more behind the comput¬
ed ; the differences amounting near the conjunc¬
tion to about fourteen minutes. When, after the
conjunction, the immersions were observed, an
acceleration was remarked, just equal to the for¬
mer retardation; so that, at the opposition, the
eclipse happened fourteen minutes sooner than
by the calculation.
The first person who offered an explanation
of these facts was Olaus Roemer, a Danish as¬
tronomer. He observed that the increase of the
retardation corresponded nearly to the increase of
the earth’s distance from Jupiter, and converse¬
ly, the acceleration to the diminution of that dis¬
tance. Hence it occurred to him, that it was
to the time which light requires to traverse
those distances that the whole series of pheno¬
mena was to he ascribed. This explanation was
so simple and satisfactory, that it was readily
received.
Though Roemer was the first who communi¬
cated this explanation to the world, yet it seems
certain that it had before occurred to Cassini,
and that he was prevented from making it known
by a consideration which does him great honour.
The explanation which the motion of light af¬
forded, seemed not to he consistent with two cir¬
cumstances involved in the phenomenon. If
such was the cause of the alternate acceleration
and retardation above described, why was it ob¬
served only in the eclipses of the first satellite,
and not in those of the other three ? This diffi¬
culty appeared so great to Cassini, that he sup¬
pressed the explanation which he would other¬
wise have given.
The other difficulty occurred to Maraldi.
Why did not an equation or allowance of the
same kind arise from the position of Jupiter,
with respect to his aphelion, for, all other things
being the same, his distance from the earth must
he greater, as he was nearer to that point of his
orbit ? Both these difficulties have since been
completely removed. If the aforesaid inequality
was not for some time observed in any satellite
but the first, it was only because the motions of
the first are the most regular, and were the
soonest understood; hut it now appears that the
same equation belongs to all the satellites. The
solution of Maraldi’s difficulty is similar; for
the quantity of what is called the equation of
the light, is now known to be affected by Jupi¬
ter’s place in his orbit.
Thus every thing conspires to prove the reality
of the motion of light, so singular on account of
the immensity of the velocity, and the smallness
of the bodies to which it is communicated.
DISSERTATION FOURTH.
615
5. ESTABLISHMENT OF ACADEMIES, &c.
About the middle of the seventeenth century
were formed those associations of scientific men,
which, under the appellation of Academies or
Philosophical Societies, have contributed so
much to the advancement of knowledge in Eu¬
rope. The Academia del Cimento of Florence,
founded in 1651, carried in its name the im¬
pression of the new philosophy. It was in the
country of Galileo where the first institution for
the prosecution of experimental knowledge might
he expected to arise; and the monuments which
it has left behind it, will ever create regret for
the shortness of its duration.
England soon after showed the same example.
It has been already remarked, that, during the
civil wars, a number of learned and scientific
men sought, in the retirement of Oxford, an
asylum from the troubles to which the country
was then a prey. They had met as early as
1645; most of them were attached to the royal
cause; and after the restoration of Charles the
Second, they were incorporated by a royal char¬
ter in 1662.
The first idea of this institution seems to have
been suggested by the writings of Bacon, who,
in recommending the use of experiment, had
severely censured the schools, colleges, and aca¬
demies of his own time, as adverse to the ad¬
vancement of knowledge;1 * * * and, in the Nova
Atlantis, had given a most interesting sketch of
the form of a society directed to scientific im¬
provement. In Germany, the Academia Natures
Curiosorum dates its commencement from 1652;
and the historian of that institution ascribes the
spirit which produced it to the writings of the
philosopher just named. These examples, and
a feeling that the union and co-operation of
numbers were necessary to the progress of expe¬
rimental philosophy, operated still more exten¬
sively. The Royal Academy of Sciences at
Paris was founded in 1666, in the reign of Louis
the Fourteenth, and during the administration
of Colbert. The Institute of Bologna in Italy
belongs nearly to the same period; but almost
all the other philosophical associations, of which
there are now so many, had their beginning in
the eighteenth century.
Frequent communication of ideas, and a regu¬
lar method of keeping up such communication,
are evidently essential to works in which great
labour and industry are to be employed, and to
which much time must necessarily be devoted;
when the philosopher must not always sit quiet¬
ly in his cabinet, but must examine nature with
his own eyes, and be present in the work-shop
of the mechanic, or the laboratory of tbe che¬
mist. These operations are facilitated by the
institutions now referred to, which, therefore,
are of more importance to the physical sciences
than to the other branches of knowledge. They
who cultivate the former are also fewer in num¬
ber, and being, of course, farther separated, are
less apt to meet together in the common inter¬
course of the world. The historian, the critic,
the poet, finds everywhere men who can enter
in some degree at least into his pursuits, who
can appreciate his merit, and derive pleasure
from his writings or his conversation. The ma-
1 “ In moribus et institutis scholarum, academiarum, collegiorum, et similium conventuum, quae doctorum hominum
sedibus et eruditionis culturae destinata sunt, omnia progressui scientiarum adversa inveniuntur. Lectiones enim et exerci-
tia ita sunt disposita, ut aliud a consuetis baud facile cuiquam in mentem veniat cogitare aut contemplari. Si vero unus
aut alter fortasse judicii libertate uti sustinuerit, is sibi soli banc operam imponere possit; ab aliorum autem consortio ni¬
hil capiet utilitatis. Sin et hoc toleraverit, tamen in capessenda fortuna industriam hanc et magnanimitatem sibi non levi
impedimento fore experietur. Studia enim hominum in ejusmodi locis in quorundam auctorum scripta, veluti in carceres,
conclusa sunt; a quibus si quis dissentiat, continuo ut homo turbidus, et rerum novarum cupidus, corripitur..../» arlibus
autem ct scientiis, tanquam in mctalli fodinis, omnia novis operibus et ulterioribus progressibus circumstrcpere debent." (Novum Ortra-
num, lib. i. cap. xc.) V
It would be gratifying to be able to observe, that the universities of Europe had contributed to the renovation of science.
The fact is otherwise; they were often the fastnesses from which prejudice and error were latest in being expelled. They
joined in persecuting the reformers of science. It has been seen, that the masters of the University of Paris were angry
with Galileo for the experiments on the descent of bodies. Even the University of Oxford brought on itself the indelible
disgrace of persecuting, in Friar Bacon, the first man who appears to have had a distinct view of the means by which
the knowledge of the laws of nature must be acquired
616
PRELIMINARY DISSERTATIONS.
thematician, the astronomer, the mechanician,
sees few men who have much sympathy with
his pursuits, or who do not look with indiffei-
ence on the objects which he puisues. The
world, to him, consists of a few individuals, by
the censures or approbation of whom the public
opinion must be finally determined, with them
it is material that he should have more frequent
intercourse than could be obtained by casual
rencounter j and he feels that the society of men
engaged in pursuits similar to his own is a ne¬
cessary stimulus to his exertions. Add to this,
that such societies become centres, in which in¬
formation concerning facts is collected from all
quarters. For all these reasons, the greatest
benefit has resulted from the scientific insti¬
tutions which, since the middle of the seven¬
teenth century, have become so numerous in
Europe.
The Royal Society of London is an associa¬
tion of men, who, without salaries or appoint¬
ment from Government, defray, by private con¬
tribution, the expense of their meetings, and
of their publications. This last is another im¬
portant service which a society so constituted
renders to science.
The demand of the public for memoirs in
Mathematics and Natural Philosophy, many of
them perhaps profound and difficult, is not suf¬
ficiently great to defray the expense of publica¬
tion, if they come forward separately and un¬
connected with one another. In a collective
state they are much more likely to draw the
attention of the public; the form in which they
appear is the most convenient both for the reader
and the author ; and if, after all, the sale of the
work is unequal to the expense, the deficiency
is made up from the funds of the society. An
institution of this kind, therefore, is a patriotic
and disinterested association of the lovers of
science, who engage not only to employ them¬
selves in discovery, but, by private contribu¬
tion, to defray the expense of scientific publica¬
tions.
The Academy of Sciences in Paris was not
exactly an institution of the same kind. It con¬
sisted of three classes of members, one of which,
the PensionnaireS) twenty in number, had sala¬
ries paid by Government, and were bound in
their turn to furnish the meetings with scien¬
tific memoirs; and each of them also, at the be¬
ginning of every year, was expected to give an
account of the work in which he was to he em¬
ployed. This institution has been of incredible
advantage to science. To detach a number of
ingenious men from every thing but scientific
pursuits; to deliver them alike from the embar¬
rassments of poverty or the temptations of
wealth; to give them a place and station in
society the most respectable and independent,
is to remove every impediment, and to add every
stimulus to exertion. To this institution, ac¬
cordingly, operating upon a people of great ge¬
nius and indefatigable activity of mind, we are
to ascribe that superiority in the mathematical
sciences which, for the last seventy years, has
been so conspicuous.
The establishment of astronomical observa¬
tories, as national or royal works, is connected
in Europe with the institution of scientific or
philosophical societies. The necessity of the
former was, indeed, even more apparent than
that of the latter. A science which has the
heavenly bodies for its object, ought, as far as
possible, to be exempted from the vicissitudes of
the earth. As it gains strength but slowly, and
requires ages to complete its discoveries, the
plan of observation must not be limited by the
life of the individual who pursues it, but must
be followed out in the same place, year after
year, to an unlimited extent. A perception of
this truth, however indistinct, seems, from the
earliest times, to have suggested the utility of
observatories, to those sovereigns who patronized
astronomy, whether they looked to that science
for real or imaginary instruction. The circle
of Osymandias is the subject of one of the most
ancient traditions in science, and has preserved
the name of a prince which otherwise would
have been entirely unknown. A building, dedi¬
cated to astronomy, made a conspicuous part of
the magnificent establishment of the school of
Alexandria. During the middle ages, in the
course of the migrations of science toward the
east, sumptuous buildings, furnished with astro¬
nomical instruments, rose successively in the
plains of Mesopotamia, and among the moun¬
tains of Tartary. An observatory in the gardens
DISSERTATION FOURTH.
617
of the Calipli of Bagdad contained a quadrant
of fifteen cubits1 in radius, and a sextant of
forty. ^ Instruments of a still larger size dis¬
tinguished the observatory of Samarcand; and
the accounts would seem incredible, if the ruins
of Benares did not, at this moment, attest the
reality of similar constructions.
On the revival of letters in Europe, establish¬
ments of the same kind were the first decisive
indications of a taste for science. We have seen
the magnificent observatory on which Tycho ex¬
pended his private fortune, and employed the
munificence of his patron, become a sad memo¬
rial (after the signal services which it had ren¬
dered to astronomy) of the instability of what¬
ever depends on individual greatness. The ob¬
servatories at Paris and London were secured
from a similar fate, by being made national es¬
tablishments, where a succession of astronomers
were to devote themselves to the study of the
heavens. The observatory at Paris was begun
in 1667, and that at Greenwich in 1675. In
the first of these, La Hire and Cassini, in the
second, Flamsteed and Halley, are at the head
of a series of successors who have done honour
to their respective nations. If there be in Britain
any establishment, in the success and conduct
of which the nation has reason to boast, it is
that of the Royal Observatory, which, in spite
of a climate which so continually tries the pa¬
tience, and so often disappoints the hopes of the
astronomer, has furnished a greater number of
observations to be completely relied on, than all
the rest of Europe put together, and afforded
the data for those tables in which the French
mathematicians have expressed, with such accu¬
racy, the past, the present, and the future con¬
dition of the heavens.
6. FIGURE AND MAGNITUDE OF THE EARTH.
The progress made during the seventeenth
century, in ascertaining the magnitude and figure
of the earth, is particularly connected with the
establishments which we have just been con¬
sidering. Concerning the figure of the earth,
no accurate information was derived from anti¬
quity, if we except that of the mathematical
principle on which it was to be determined.
The measurement of an arch of the meridian
was attempted by Eratosthenes of Alexandria,
in perfect conformity with that principle, but by
means very inadequate to the importance and
difficulty of the problem. By measuring the
sun’s distance from the zenith of Alexandria on
the solstitial day, and by knowing, as he thought
he did, that on the same day the sun was ex¬
actly in the zenith of Syene, he found the dis¬
tance in the heavens between the parallels of
those places to be 7° 12', or a 50th part of the
circumference of a great circle. Supposing, then,
that Alexandria and Syene were in the same
meridian, nothing more was required than to
find the distance between them, which, when
multiplied by 50, would give the circumference
of the globe. The manner in which this was
attempted by Eratosthenes, is quite characteris¬
tic of the infant state of the arts of experiment
and observation. He took no trouble to ascer¬
tain whether Alexandria and Syene were due
north and south of one another: the truth is,
that the latter is considerably east of the former;
so that, though their horizontal distance had
been accurately known, a considerable reduction
would have been necessary, on account of the
distance of the one from the meridian of the
other. It does not appear, however, that Era¬
tosthenes was at any more pains to ascertain the
distance than the bearing of the two places. He
assumed the former just as it was commonly es¬
timated ; and, indeed, it appears that the dis¬
tance was not measured till long afterwards,
when it was done by the command of Nero.
It was in this way that the ancients made ob¬
servations and experiments; the mathematical
principles might be perfectly understood, but
the method of obtaining accurate data for the
application of those principles was not a subject
of attention. The power of resolving the pro¬
blem was the main object; and the actual solu¬
tion was a matter of very inferior importance.
Twenty-two feet three inches.
DISS. IV., PART I.
2 Sixty feet five inches^
4 i
618
PRELIMINARY DISSERTATIONS.
The slowness with which the art of making ac¬
curate experiments and observations has been
matured, and tbe great distance it has kept be¬
hind theory, is a remarkable fact in the history
of the physical sciences. It has been remarked,
that mathematicians had found out the area of
the circle, and calculated its circumference to
more than a hundred places of decimals, before
artists had divided an arch into minutes of a de¬
gree ; and that many excellent treatises had been
written on the properties of curves, before a
straight line had been drawn of any considerable
length, or measured with any tolerable exact¬
ness, on the surface of the globe.1
The next measurement on record is that of the
astronomers of Almamon, in the plains of Me¬
sopotamia ; and the manner of conducting the
operation appears to have been far more accu¬
rate than that of the Greek philosophers; but,
from a want of knowledge of the measures em¬
ployed, it has conveyed no information to pos¬
terity.
The first arch of the meridian, measured in
modern times with an accuracy any way cor¬
responding to the difficulty of the problem, was
by Snellius, a Dutch mathematician, who has
given an account of it in a volume which he
calls Eratosthenes Batavus, published in 1617.
The arch was between Bergen-op-Zoom and Alk-
maar ; its amplitude was l* 11' 30", and the dis¬
tance was determined by a series of triangles,
depending on a base line carefully measured.
The length of the degree that resulted was 55,021
toises, which, as was afterwards found, is consi¬
derably too small. Certain errors were disco¬
vered, and when they were corrected, the degree
came out 57,033 toises, which is not far from
the truth. The corrections were made by Snel¬
lius himself, who measured his base over again,
and also the angles of the triangles. He died,
however, before he could publish the result.
Muschenbroek, who calculated the whole anew
from his papers, came to the conclusion just
mentioned, which, of course, was not known till
long after the time when the measure was exe¬
cuted. No advantage, accordingly, was derived
to the world from this measurement till its value
was lost in that of other measurements still
more accurately conducted.
A computation which, for the time, deserves
considerable praise, is that of Norwood, in 1635,
who measured the distance between London and
York, taking the bearings as he proceeded along
the road, and reducing all to the direction of the
meridian, and to the horizontal plane. The dif¬
ference of latitude he found, by observation of
tbe solstices, to be 2° 28'; and from that and his
measured distance, he concluded the degree to
be 367,176 feet English, or 57,800 toises. This
has been found to be a near approximation; yet
his method was not capable of great accuracy,
nor did he always execute it in the best manner.
“ Sometimes,” says he, “ I measured, sometimes
I paced ; and I believe I am within a scantling of
the truth.”
Fernel, a French physician, measured with a
wheel from Paris to Amiens, which are nearly
in the same meridian, and he determined the de¬
gree from thence to be 56,746 French toises ; a
result which falls short of the truth, though not
very considerably.
These investigations, it is plain, could not but
leave considerable uncertainty with respect to
the magnitude of the earth. The Academy of
Sciences became interested in the question, and the
measurement of an arch in the meridian was un¬
dertaken under its auspices, and executed by the
Abbe Picard, already known for his skill in the
operations of practical geometry. He followed a
method similar to that of Snellius, according to
which, the distance between Amiens and Mal-
voisine was found from a series of triangles, and
a base of 5663^ toises. He determined the dif¬
ference of latitude by means of a zenith sector of
ten feet radius, and found it to be 1° 22' 55". The
whole distance was 78,850 toises, whence the
degree came out 57,060 toises. This was the
first measurement of a degree of the meridian
on which perfect reliance could be placed.
Hitherto no doubt had been entertained of the
spherical figure of the earth, and, of consequence,
of the equality of all the degrees of the meridian,
so that if one was known, the whole circum¬
ference was determined. Men, with the preci-
1 Edinburgh Review, vol. Y. p. 391.
DISSERTATION FOURTH.
619
pitation which they so often manifest, of assum¬
ing, without sufficient evidence, the conclusion
which appears most simple, were no sooner sa¬
tisfied that the earth was round, than they sup¬
posed it to be truly spherical. An observation
soon occurred, which gave reason to suspect,
that much more must be done before its figure or
its magnitude could be completely ascertained.
With a view of observing the sun’s altitude in
the vicinity of the equator, where the distance
from the zenith being inconsiderable, the effects
of refraction must be of small account, it was
agreed, by the same academy, to send an astro¬
nomer, M. Richer, to make observations at the
island of Cayenne, in South America.
Richer observed the solstitial altitude of the
sun at that place in 1672, and found the dis¬
tance of the tropics to be 46° 57' 4", and there¬
fore the obliquity of the ecliptic 23° 28' 32";
agreeing almost precisely with the determination
of Cassini.
The most remarkable circumstance, however,
which occurred in the course of this voyage, was,
that the clock, though furnished with a pendu¬
lum of the same length which vibrated seconds
at Paris, was found, at Cayenne, to lose two
minutes and a half a-day nearly. This created
great astonishment in France, especially after
the accuracy of it was confirmed by the observa¬
tions of Varin and Deshayes, who, some years
afterwards, visited different places on the coasts
of Africa and America, near the line, and found
the necessity of shortening the pendulum, to
make it vibrate seconds in those latitudes. The
first explanation of this remarkable phenomenon
was given by Newton, in the third book of his
Principia, published in 1687, where it is de¬
duced as a necessary consequence of the earth’s
rotation on its axis, and of the centrifugal force
thence arising. That force changes both the di¬
rection and the intensity of gravity, giving to the
earth an oblate spheroidal figure, more elevated
at the equator than the poles, and making bodies
fall, and pendulums vibrate, more slowly in low
than in high latitudes.
This solution, however, did not, any more than
the book in which it was contained, make its
way very readily into France. The first expla¬
nation of the retardation of the pendulum, which
was received there, was given by Huygens in
1690. Huygens deduced it also from the cen¬
trifugal force, arising from the earth’s rotation,
and the view which he took was simpler, though
much less accurate than that of Newton. It had
indeed the simplicity which often arises from
neglecting one of the essential conditions of a
problem; but it was nevertheless ingenious, and
involved a very accurate knowledge of the nature
of centrifugal force.—I am thus brought to touch
on a subject which belongs properly to the
second part of this Dissertation, for which the
fuller discussion of it must of course be reserved.
SECTION V.
OPTICS.
1. OPTICAL KNOWLEDGE OF THE ANCIENTS.
On account of tbe rectilineal propagation of success, to explain the laws of vision, before a
light, the phenomena of optics are easily express- similar attempt had been made with respect to
ed in the form of mathematical propositions, and any other branch of terrestrial Physics, and at
seem, as it were, spontaneously to offer them- least fifty years before the researches of Archi-
selves to the study of geometers. Euclid, per- medes had placed mechanics among the number
cemng this affinity, began to apply the science of the mathematical sciences,
which he had already cultivated with so much In the treatise ascribed to Euclid, there are,
620
PRELIMINARY DISSERTATIONS.
however, only two physical principles which have
completely stood the test of subsequent impiove-
ment. The first of these is the proposition just
referred to, that a point in any object is seen in
the direction of a straight line drawn from the
eye to that point; and the second is, that when
a point in an object is seen by reflection from a
polished surface, the lines drawn from the eye
and from the object to the point whence the re¬
flection is made, are equally inclined to the re¬
flecting surface. These propositions are assum¬
ed as true: they were, no doubt, known before
the time of Euclid ; and it is supposed that the
discovery of them was the work of the Platonic
school. The first of them is the foundation of
Optics proper, or the theory of vision by direct
light; the second is the foundation of Catoptrics,
or the theory of vision by reflected light. Diop¬
trics, or vision by refracted light, had not yet
become an object of attention.
Two other principles which Euclid adopted
as postulates in his demonstrations, have not
met with the same entire confirmation from ex¬
periment, and are indeed true only in certain
cases, and not universally, as he supposed. The
first of these is, that we judge of the magnitude
of an object altogether by the magnitude of the
optical angle, or the angle which it subtends at
the eye. It is true that this angle is an import ¬
ant element in that judgment; and Euclid, by
discovering this, came into the possession of a
valuable truth; but by a species of sophistry, very
congenial to the human mind, he extended the
principle too far, and supposed it to be the only
circumstance which determines our judgment
of visible magnitude. It is, indeed, the only
measure which we are furnished with directly
by the eye itself; but there are few cases in
which we form our estimate without first appeal¬
ing to the commentary afforded by the sensations
of touch, or the corrections derived from our
own motion.
Another principle, laid down by the same geo¬
meter, is in circumstances nearly similar to the
preceding. According to it, the place of any
point of an object seen by reflection is always the
intersection of the reflected ray, with the per¬
pendicular drawn from that point to the reflect¬
ing surface. The proof offered is obscure and
defective; the proposition, however, is true, of
plain speculums always, and of spherical as far
as Euclid’s investigations extended, that is, while
the rays fall on the speculum with no great ob¬
liquity. His assumption, therefore, did not af¬
fect the truth of his conclusions, though it would
have been a very unsafe guide in more general
investigations. The book is in many other re¬
spects imperfect, the reasoning often unsound,
and the whole hardly worthy of the great geo¬
meter whose name it bears. There is, however,
no doubt that Euclid wrote on the subject of op¬
tics, and many have supposed that this treatise
is a careless extract, or an unskilful abridgement
of the original work.
Antiquity furnished another mathematical
treatise on optics, that of the astronomer Ptolemy.
This treatise, though known in the middle ages,
and quoted by Roger Bacon, had disappeared,
and was supposed to be entirely lost, till within
these few years, when a manuscript on optics,
professing to be the work of Ptolemy, and to be
translated from the Arabic, was found in the
King’s Library at Paris. The most valuable
part of this work is that which relates to refrac¬
tion, from whence it appears that many experi¬
ments had been made on that subject, and the
angles of incidence and refraction, for different
transparent substances, observed with so much
accuracy, that the same ratio, very nearly, of the
sines of these angles, from air into water or into
glass, is obtained from Ptolemy’s numbers, which
the repeated experiments of later times have
shown to be true. The work, however, in the
state in which it now appears, is very obscure,
the reasoning often deficient in accuracy, and the
mathematical part much less perfect than might
have been expected. Modern writers, presum¬
ing partly on the reputation of Ptolemy, and
partly guided by the authority of Roger Bacon,
had ascribed to this treatise more merit than it
appears to possess; and, of consequence, had
allowed less to the Arabian author Alhazen,
who comes next in the order of time, than of
right belongs to him. Montucla, on the autho¬
rity of Bacon, says, that Ptolemy ascribed the
increase of the apparent magnitude of the heaven¬
ly bodies near the horizon, to the greater dis¬
tance at which they are supposed to be, on ac-
DISSERTATION FOURTH.
621
count of tlie number of intervening objects across
which they are seen. Ptolemy’s explanation,
however, as stated by Delambre,1 from the manu¬
script just mentioned, is quite different from
this, and amounts to no more than the vague
and unsatisfactory remark, that an observer looks
at the bodies near the zenith in a constrained
posture, and in a situation to which the eye is
not accustomed. The former explanation, there¬
fore, given ,by Alhazen, but supposed to have
been borrowed from Ptolemy, must now be re¬
turned to its right owner. It is the best expla¬
nation yet known.
These are the only mathematical treatises on
optics of any consideration which the ancients
have transmitted to us ;2 but many metaphysical
speculations on light and vision are to be found
in the writings of the philosophers. Aristotle
defined light much as he had defined motion;
the act or energy of a transparent body, in as much
as it is transparent. The reason for calling light
an act of a transparent body is, that, though a
body may be transparent in power or capacity,
it does not become actually transparent but by
means of light. Light brings the transparency
into action; it is, therefore, the act of a trans¬
parent body. In such miserable puerilities did
the genius of this great man exhaust itself, owing
to the unfortunate direction in which his re¬
searches were carried on.
In his further speculations concerning light,
he denied it to be a substance; and his argu¬
ment contains a singular mixture of the ingeni¬
ous and the absurd. The time, he says, in which
light spreads from one place to another is infi¬
nitely small, so that light has a velocity which
is infinitely great. Now, bodies move with a
velocity inversely as the quantities of matter
which they contain; light, therefore, cannot
contain any matter, that is, it cannot be mate¬
rial.3 That the velocity of light was infinitely
great, seemed to him to follow from this, that
its progress, estimated either in the direction of
north and south or of east and west, appeared
to be instantaneous. In the opinion of the
Platonists, and of the greater part of the an¬
cients, vision was performed by means of certain
rays which proceeded from the eye to the object,
though they did not become the instruments of
conveying sensations to the mind, but in conse¬
quence of the presence of light. In this theory,
we can now see nothing but a rude and hasty
attempt to assimilate the sense of sight to that
of touch, without inquiring sufficiently into the
particular characters of either.
Epicurus, and the philosophers of his school,
as we learn from Lucretius, entertained more
correct notions of vision, though they were still
far from the truth. They conceived vision to
be performed in consequence of certain simu-
lacra, or images continually thrown off from the
surfaces of bodies, and entering the eye. This
was the substitute in their philosophy for rays
of light, and had at least the merit of represent¬
ing that which is the medium of vision, or which
forms the communication between the eye and
external objects, as something proceeding from
the latter. The idea of simulacra, or spectra,
flying off continually from the surfaces of bodies,
and entering the eye, was perhaps as near an
approach to the true theory of vision as could
be made before the structure of the eye was
understood.
In the arts connected with optics, the ancients
had made some progress. They were sufficiently
acquainted with the laws of reflection to con-
1 Connoissance. des Terns, 1816, p. 245, &c. The glimpses of truth, not destined to be fully discovered till many ages
afterwards, which are found in the writings of the ancients, are always interesting. Ptolemy distinguishes what has since been
called the virtualfoeus, which takes place in certain cases of reflection, from spherical specula. He remarks, that colours are
confounded by the rapidity of motion, and gives the instance of a wheel painted with different colours, and turned quickly
round.
2 Another Greek treatise on optics, that of Heliodorus of Larissa, has been preserved, and was first published by Eras¬
mus Bartholinus at Paris, in 1657- It is a superficial work, which, to a good deal of obscure and unsound metaphysics,
adds the demonstration of a few very obvious truths. The author holds the opinion, that vision is performed by the emission
of something from the eyes; and the reason which he assigns is, that the eyes are convex, and more adapted to emit than
to receive. His metaphysics may be judged of from this specimen. He has not been made mention of by any ancient
author, and the time when he wrote is unknown. As he quotes, however, the writings of Ptolemy and Hero, he must have
been later than the first century.
3 The truth of the mathematical proposition, that A = 0, was perceived by Aristotle. A strong intellect is always
visible in the midst of his greatest errors.
622
PRELIMINARY DISSERTATIONS*
struct mirrors both plane and spherical. They
made them also conical; and it appears from
Plutarch, that the fire of Vesta, when extin¬
guished, was not permitted to be rekindled hut
by the rays of the sun, which were condensed
by a conical speculum of copper. The minors
with which Archimedes set fire to the Roman
galleys have been subjects of much discussion,
and the fact was long disbelieved, on the ground
of being physically impossible. The experi¬
ments of Kircher and Buffon showed that this
impossibility was entirely imaginary, and that
the effect ascribed to the specula of the Greek
geometer might be produced without much dif¬
ficulty. There remains now no doubt of their
reality. A passage from Aristophanes1 gives
reason to believe that, in his time, lenses of
glass were used for burning, by collecting the
rays of the sun; but in a matter that concerns
the history of science, the authority of a comic
poet and a satirist would not deserve much at¬
tention, if it were not confirmed by more sober
testimony. Pliny, speaking of rock crystal,2 3
says that a globe or ball of that substance was
sometimes used by the physicians for collecting
the rays of the sun, in order to perform the
operation of cautery. In another passage, he
mentions the power of a glass globe filled with
water, to produce a strong heat when exposed
to the rays of the sunj and expresses his sur¬
prise that the water itself should all the while
remain quite cold.
With respect to the power of glasses to mag¬
nify objects seen through them, or to render
such objects more distinct, the ancients appear
to have observed ill, and to have reasoned worse.
“ Li terse, quamvis minutse et obscurse, per vi-
tream pilam aqua plenam majores clarioresque
cernuntur. Sidera ampliora per nubem adspi-
cienti videntur; quia acies nostra in humido labi-
tur, nec apprehendere quod vult jideliter potest”5
This passage, and the speculations concerning
the rainbow in the same place, when they are
considered as containing the opinions of some
of the most able and best-informed men of an¬
tiquity, must be admitted to mark, in a very
striking manner, the infancy of the physical
sciences.
2. FROM ALHAZEN TO KEPLER.
An interval of nearly a thousand years divid¬
ed Ptolemy from Alhazen, who, in the history
of optical discovery, appears as his immediate
successor. This ingenious Arabian lived in the
eleventh century, and his merit can be more
fairly, and will be more highly appreciated, now
that the work of his predecessor has become
known. The merit of his book on Optics was al¬
ways admitted; but he was supposed to have bor¬
rowed much from Ptolemy, without acknowledg¬
ing it; and the prejudices entertained in favour
of a Greek author, especially of one who had been
for so many years a legislator in science, gave
a false impression, both of the genius and the
integrity of his modern rival. The work of Al¬
hazen is, nevertheless, in many respects, supe¬
rior to that of Ptolemy, and in nothing more
than in the geometry which it employs. The
problem known by his name, to find the point
in a spherical speculum, at which a ray coming
from one given point shall be reflected to ano¬
ther given point, is very well resolved in his
book, though a problem of so much difficulty,
that Montucla hazards the opinion, that no Ara¬
bian geometer was ever equal to the solution of
it.4 It is now certain, however, that the solu¬
tion, from whatever quarter it came, was not
borrowed from Ptolemy, in whose work no men¬
tion is made of any such question; and it may
very well be doubted, whether, had this problem
1 Aristophanis Nubes, v. 766. edit. Brunck.
2 Hist. Nat. lib. xxxvii. cap. ii.
3 Seneca, Nat. Qucest. lib. i. cap. vi. .
* Barrow, in his 9th lecture, says of this problem, that it may truly be called as hardly any one more dimcult
had then been attempted by geometers. He adds, that, after trying the analysis in many different ways, he had found
nothing preferable to the solution of Alhazen, which he therefore gives, only freed from the prolixness and obscurity wit.
which the original is chargeable. (Lectiones Optica;, sect. 9, p. 65.) A very elegant solution of the same problem is given
by Simson, at the end of his Conic Sections.
*
DISSERTATION FOURTH.
623
been proposed to him, the Greek geometer would
have appeared to so much advantage as the
Arabian.
The account which the latter gives of the
augmentation of the diameters of the heavenly
bodies near the horizon, has been already men¬
tioned. He treated also of the refraction of
light by transparent bodies, and particularly of
the atmospheric refraction; but not with the
precision of Ptolemy, whose optical treatise De-
lambre seems to think it probable that he had
never seen. The anatomical structure of the
eye was known to him; concerning the uses of
the different parts he had only conjectures to
offer; hut on seeing single with two eyes, he
made this very important remark, that, when
corresponding parts of the retina are affected,
we perceive hut one image.
Prolixity and want of method are the faults
of Alhazen. Vitello,1 a learned Pole, comment¬
ed on his works, and has very much improved
their method and arrangement in a treatise pub¬
lished in 1270. He has also treated more fully
of the subject of refraction, and reduced the re¬
sults of his experiments into the form of a table,
exhibiting the angles of refraction corresponding
to the angles of incidence, which he had tried in
water and glass. It was not, however, till long
after this period that the law which connects
these angles was discovered. The cause of re¬
traction appeared to him to be the resistance
which the rays suffer in passing into the denser
medium of water or glass; and one can see in
his reasoning an obscure idea of the resolution
of forces. He also treats of the rainbow, and
remarks, that the altitude of the sun and bow
together always amount to 42 degrees. He next
considers the structure of the eye, of which he
has given a tolerably accurate description; and
proves, as Alhazen had before done,9 that vision
is not performed by the emission of rays from
the eye.
Roger Bacon, distinguished for pursuing the
path of true philosophy in the midst of an age
of ignorance and error, belongs to the same pe-
The name of this author is commonly written Vitellio.
nis own name.
* Alhazen, Opt. lib. i.
* Smith’s Optics, vol. II. Remarks, sect. 76.
riod, and applied to the study of optics with
peculiar diligence. It does not appear, however,
that he added much to the discoveries of Alha¬
zen and Ptolemy, with whose writings, particu¬
larly those of the former, he seems to have been
well acquainted. In some things he was much
behind the Arabian optician, as he supposed,
with the ancients, that vision is performed by
rays emitted from the eye. It must, however,
be allowed, that the arguments employed on both
sides of this question are so weak and inconclu¬
sive, as very much to diminish the merit of being
right, and the demerit of being wrong. What
is most to the credit of Bacon, is the near ap¬
proach he appears to have made to the know¬
ledge of lenses, and their use in assisting vision.
Alhazen had remarked, that small objects, let¬
ters, for instance, viewed through a segment of
a glass sphere, were seen magnified, and that it
is the larger segment which magnifies the most.
The spherical segment was supposed to be laid
with its base on the letters, or other minute ob¬
jects which were to be viewed. Bacon recom¬
mends the smaller segment, and observes, that
the greater, though it magnify more, places the
object farther off than its natural position, while
the other brings it nearer. This shows suffi¬
ciently, that he knew how to trace the progress
of the rays of light through a spherical transpa¬
rent body, and understood, what was the thing
least obvious, how to determine the place of the
image. Smith, in his Optics, endeavours to
show, that these conclusions were purely theo¬
retical, and that Roger Bacon had never made
any experiments with such glasses, notwith¬
standing that he speaks as if he had done so.5
This severe remark proceeds on some slight in¬
accuracy in Bacon’s description, which, how¬
ever, does not seem sufficient to authorize so
harsh a conclusion. The probability appears
rather to be, as Molineux supposed, that Bacon
had made experiments with such glasses, and
was both practically and theoretically acquainted
with their properties. At the same time, it must
be acknowledged, that his credulity on many
He may be supposed to have known best the orthography of
624
PRELIMINARY DISSERTATIONS.
points, and his fondness for the marvellous,
which, with every respect for his talents, it is
impossible to deny, take something away from
the force of his testimony, except when it is very
expressly given. However that may he in the
present case, it is probable that the knowledge
of the true properties of these glasses, whether
it was theoretical or practical, may have had a
share in introducing the use of lenses, and in
the invention of spectacles, which took place not
long after.
It would be desirable to ascertain the exact
period of an invention of such singular utility as
this last; one that diffuses its advantages so
widely, and that contributes so much to the so¬
lace and comfort of old age, by protecting the
most intellectual of the senses against the gene¬
ral progress of decay. In the obscurity of a
dark age, careless about recording discoveries of
which it knew not the principle or the value, a
few faint traces and imperfect indications serve
only to point out certain limits within which the
thing sought for is contained. Seeking for the
origin of a discovery, is like seeking for the
source of a river where innumerable streams
have claims to the honour, between which it is
impossible to decide, and where the only thing
that can be known with certainty is the boun¬
dary by which they are all circumscribed. The
reader will find the evidence concerning the in¬
vention of spectacles very fully discussed in
Smith’s Optics, from which the most probable
conclusion is, that the date goes back to the
year 1313, and cannot with any certainty be
traced farther.1 2
The lapse of more than two hundred years
brings us down to Maurolycus, and to an age
when men of science ceased to be so thinly scat¬
tered over the wastes of time. Maurolycus,
whose knowledge of the pure mathematics has
been already mentioned, was distinguished for
his skill in optics. He was acquainted with the
crystalline lens, and conceived that its office is
to transmit to the optic nerve the species of ex¬
ternal objects; and in this process he does not
consider the retina as any way concerned. This
theory, though so imperfect, led him neverthe¬
less to form a right judgment of the defects of
short-sighted and long-sighted eyes. In one of
his first works, Theoremata de Lumine et Umbra,
he also gives an accurate solution of a question
proposed by Aristotle, viz. why the light of the
sun, admitted through a small hole, and received
on a plane at a certain distance from it, always
illuminates a round space, whatever be the figure
of the hole itself; whereas, through a large aper¬
ture, the illuminated space has the figure of the
aperture. To conceive the reason of this, sup¬
pose that the figure of the hole is a triangle; it
is plain that at each angle the illuminated space
will be terminated by a circular arch, of which
the centre corresponds to the angular point, and
the radius to the angle subtended by the sun’s
semidiameter. Thus the illuminated space is
rounded off at the angles; and when the hole is
so small that the size of those roundings bears a
large proportion to the distance of their centres,
the figure comes near to a circle, and may be to
appearance quite round. This is the true solu¬
tion, and the same with that of Maurolycus.
The same author appears also to have observed
the caustic curve formed by reflection from a
concave speculum.
A considerable step in optical discovery was
made at this time by Baptista Porta, a Neapo¬
litan, who invented the Camera Obscara, about
the year 1560, and described it in a work en¬
titled Magia Naturalis. The light was admitted
through a small hole in the window-shutter of
a dark room, and gave an inverted picture of
the objects from which it proceeded, on the op¬
posite wall. A lens was not employed in the
first construction of this apparatus, but was af¬
terwards used; and Porta went so far as to
consider how the effect might be produced with¬
out inversion. He appears to have been a man
of great ingenuity; and though much of the
Magia Naturalis is directed to frivolous objects,
it indicates a great familiarity with experiment
and observation. It is remarkable, that we find
mention made in it of the reflection of cold by
a speculum,e an experiment which, of late, has
1 Smith’s Optics, vol. II. Remarks, sect. 75.
2 Magia Naturalis, lib. xvii. cap. iv. p. 583. Amsterdam edit. I6G4.
DISSERTATION FOURTH.
625
drawn so much attention, and has been supposed
to be so entirely new. The cold was perceived
by making the focus fall on the eye, which, in
the absence of the thermometer, was perhaps
the best measure of small variations of tempe¬
rature. Porta’s hook was extremely popular;
and when we find it quickly translated into Ita¬
lian, French, Spanish, and Arabic, we see how
much the love of science was now excited, and
what effects the art of printing was now begin¬
ning to produce. Baptista Porta was a man of
fortune, and his house was so much the resort
of the curious and learned at Naples, that it
awakened the jealousy with which the court of
Rome watched the progress of improvement.
How grievous it is to observe the head of the
Christian church in that and the succeeding age,
like the Anarch old in Milton, reigning in the
midst of darkness, and complaining of the en¬
croachments which the realm of light was con¬
tinually making on his ancient empire !
The constitution of the eye, and the functions
of the different parts of which it consists, were
not yet fully understood. Maurolycus had
nearly discovered the secret; and it was but a
thin, though to him an impenetrable veil, which
still concealed one important part of the truth.
This veil was drawn aside by the Neapolitan
philosopher; but the complete discovery of the
truth was left to Kepler, who, to the glory of
finding out the true laws of the planetary sys¬
tem, added that of first analyzing the whole
scheme of nature in the structure of the eye.
He perceived the exact resemblance of this or¬
gan to the dark chamber, the rays entering the
pupil being collected by the crystalline lens, and
the other humours of the eye, into foci, which
paint on the retina the inverted images of exter¬
nal objects. By another step of the process, to
which our analysis can never he expected to
extend, the mind perceives the images thus
formed, and refers them at the same time to
things without.
It seemed a great difficulty, that, though the
images he inverted, the objects are seen erect;
hut when it is considered that each point in the
object is seen in the direction of the line in
which the light passes from it to the retina,
through the centre of the eye, it will appear that
the upright position of the object is a necessary
consequence of this arrangement.
Kepler’s discovery is explained in his Para-
lipomena in VitelUonem,1 (Remarks on the Optics
of Vitello) a work of great genius, abounding
with new and enlarged views, though mixed occa¬
sionally with some unsound and visionary specu¬
lations. This book appeared in 1604. In the
next article we shall have occasion to return to
the consideration of other parts of Kepler’s op¬
tical discoveries.
3. FROM KEPLER TO THE COMMENCEMENT OF NEWTON’S OPTICAL DISCOVERIES.
The rainbow had, from the earliest times,
been an object of interest with those who be¬
stowed attention on optical appearances; but it
is much too complicated a phenomenon to be
easily explained. In general, however, it was
understood to arise from light reflected by the
drops of rain falling from a cloud opposite to
the sun. The difficulty seemed to be, how to
account for the colour, which is never produced
in white light, such as that of the sun, by mere
reflection. Maurolycus advanced a considerable
step when he supposed that the light enters the
drop, and acquires colour by refraction; but in
tracing the course of the ray he was quite be¬
wildered. Others supposed the refraction and
the colour to be the effect of one drop, and the
reflection of another; so that two refractions
and one reflection were employed, but in such
a manner as to be still very remote from the
truth.
Antonio de Dominis, archbishop of Spalatro,
had the good fortune to fall upon the true ex¬
planation. Having placed a bottle of water op¬
posite to the sun, and a little above his eye, he
saw a beam of light issue from the under side
of the bottle, which acquired different colours,
in the same order and with the same brilliancy
as in the rainbow, when the bottle was a little
4 K
DISS. IV., PART I.
1 Caput v. De Modo Visionis.
626
PRELIMINARY DISSERTATIONS.
raised or depressed. From comparing all the
circumstances, he perceived that the rays had
entered the bottle, and that, after two refractions
from the convex part, and a reflection from the
concave, they were returned to the eye tinged
with different colours, according to the angle at
which the ray had entered. The rays that gave
the same colour made the same angle with the
surface, and hence all the drops that gave the
same colour must he arranged in a circle, the
centre of which was the point in the cloud op¬
posite to the sun. This, though not a complete
theory of the rainbow, and though it left a great
deal to occupy the attention, first of Descartes,
and afterwards of Newton, was perfectly just,
and carried the explanation as far as the prin¬
ciples then understood allowed it to go. The
discovery itself may he considered as an ano¬
maly in science, as it is one of a very refined
and subtile nature, made by a man who has
given no other indication of much scientific sa¬
gacity or acuteness. In many things his writings
show great ignorance of principles of optics well
known in his own time; so that Boscovich, an
excellent judge in such matters, has said of
him, “ homo opticarum rerum, supra id quod
patiatur ea setas, imperitissimus.” The hook con¬
taining this discovery was published in 1611.1
A discovery of the same period, hut somewhat
earlier, will always he considered as among the
most remarkable in the whole circle of human
knowledge. It is the invention of the telescope,
the work in which (by following unconsciously
the plan of nature in the formation of the eye)
man has come the nearest to the construction of
a new organ of sense. For this great invention,
in its original form, we are indebted to accident,
or to the trials of men who had little knowledge
of the principles of the science on which they
were conferring so great a favour. A series of
scientific improvements, continued for more
than two hundred years, has continually added
to the perfection of this noble instrument, and
has almost entitled science to consider the tele¬
scope as its own production.
It will readily be believed, that the origin of
such an invention has been abundantly inquired
into. The result, however, as is usual in such
cases, has not been quite satisfactory; and all
that is known with certainty is, that the honour
belongs to the town of Middleburg in Zealand,
and that the date is between the last ten years
of the sixteenth century and the first ten of the
seventeenth. Two different workmen belonging
to that town, Zachariah Jans and John Lap-
prey, have testimonies in their favour, between
which it is difficult to decide: the former goes
back to 1590, the latter comes down to about
1610. It is not of much consequence to settle
the priority in a matter which is purely acci¬
dental; yet one would not wish to forget or
mistake the names of men whom even chance
had rendered so great benefactors to science.
What we know with certainty is, that the ac¬
count of the effect produced by this new combi¬
nation of glasses being carried to Galileo in
1610, led that great philosopher to the construc¬
tion of the telescope, and to the interesting dis¬
coveries already enumerated. By what prin¬
ciple he was guided to the combination, which
consists of one convex and one concave lens, he
has not explained, and we cannot now exactly
ascertain. He had no doubt observed, tbat a
convex lens, such as was common in spectacles,
formed images of objects, which were distinctly
seen when thrown on a wall or on a screen. He
might observe also, that if the image, instead of
falling on the screen, were made to fall on the
eye, the vision was confused and indistinct. In
the trials to remedy this indistinctness by means
of another glass, it would be found that a con¬
cave lens succeeded when placed before the eye,
the eye itself being also a little more advanced
than the screen had been.
This instrument, though very imperfect, com¬
pared with those which have been since con¬
structed, gave so much satisfaction, that it re¬
mained long without any material improvement.
Descartes, whose treatise on Optics was written
near thirty years after the invention of the tele¬
scope, makes no mention of any but such as is
composed of a convex object-glass and a con¬
cave eye-glass. The theory of it, indeed, was
given by Kepler in his Dioptrics, in 1611, when
1 De Radiis Lucis in Vitris pcrspectivis et Iride. Venetiis, 4to.
DISSERTATION FOURTH.
627
he also pointed out the astronomical telescope, posed to he produced, till it do so likewise. Now,
or that which is composed of two convex lenses, the general truth which Snellius found to hold,
and inveits the objects. He did not, however, whatever was the position of the incident ray,
construct a telescope of that kind, which appears is, that the segments of the refracted ray and of
to have heen first done by Scheiner, who has the incident ray, intercepted hy these parallels,
given an account of it in the Rosa Ursina, in had always the same ratio to one another. If
1650, quoted hy Montucla.1 either of the media were changed, that through
After the invention of the telescope, that of which the incident ray, or that through which
the mici oscope was easy; and it is also to Gali- the refracted ray passed, this ratio would he
leo that we.are indebted for this instrument, changed; hut while the media remained the same,
which discovers an immensity on the one side the ratio continued unalterable. It is seldom
of man, scarcely less wonderful than that which that a general truth is seen at first under the
the telescope discovers on the other. The ex- most simple aspect: this law admits of being
tension and divisibility of matter are thus ren- more simply expressed; for, in the triangle form-
dered to the natural philosopher almost as unli- ed hy the two segments of the rays, and by the
mited as the extension and the divisibility of parallel which they intersect, the said segments
space are to the geometer. have the same ratio with the sines of the oppo-
The theory of the telescope, now become the site angles, that is, with the sines of the angles
main object in optical science, required that the of incidence and refraction. The law, therefore,
law of refraction should, if possible, he accurate- comes to this, that, in the refraction of light hy
ly ascertained. This had not yet heen effected; the same medium, the sine of the angle of inci-
and Kepler, whose Dioptrics was the most per- dence has to the sine of the angle of refraction
feet treatise on refraction which had yet appear- always the same ratio. This last simplification
ed, had been unable to determine the general did not occur to Snellius; it is the work of Des-
principle which connects the angles of incidence cartes, and was first given in his Dioptrics, in
and refraction. In the case of glass, he had 1637, where no mention is made of Snellius, and
found by experiment, that those angles, when the law of refraction appears as the discovery of
small, are nearly in the ratio of three to two; the author. This naturally gave rise to heavy
and on this hypothesis he had found the focus of charges against the candour and integrity of the
a double convex lens, when the curvature of both French philosopher. The work of Snellius had
sides is equal, to be the centre of curvature of never been published, and the author himself
the side turned toward the object,—a proposition was dead; hut the proposition just referred to
which is known to coincide with experiment, had heen communicated to his friends, and had
From the same approximation he derived other been taught hy his countryman Professor Hor-
conclusions, which were found useful in prac- tensius, in his lectures. There is no doubt,
tice, in the cases where the angles just mention- therefore, that the discovery was first made by
ed were very small. Snellius; but whether Descartes derived it from
The discovery of the true law of refraction him, or was himself the second discoverer, re-
was the work of Snellius, the same mathemati- mains undecided. The question is one of those,
cian whose labours concerning the figure of the where a man’s conduct in a particular situation
earth were before mentioned. In order to ex- can only he rightly interpreted from his general
press this law, he supposed a perpendicular to character and behaviour. If Descartes had been
the refracting surface, at the point where the uniformly fair and candid in his intercourse with
refraction is made, and also another line paral- others, one would have rejected with disdain a
lei to this perpendicular at any given distance suspicion of the kind just mentioned. But the
from it. The refracted ray, as it proceeds, will truth is, that he appears throughout a jealous
meet this parallel, and the incident ray is sup- and suspicious man, always inclined to depress
1 Yol. II. p. 234. 2d edit.
628
preliminary dissertations.
and conceal the merit of others. In speaking of
the inventor of the telescope, he has told minute¬
ly all that is due to accident, hut has passed
carefully over all that proceeded from design,
and has incurred the reproach of relating the
origin of that instrument, without mentioning
the name of Galileo. In the same manner, he
omits to speak of the discoveries of Kepler, so
nearly connected with his own ; and in treating
of the rainbow, he has made no mention of An¬
tonio de Dominis. It is impossible that all this
should not produce an unfavourable impression;
and hence it is, that even the warmest admirers
of Descartes do not pretend that his conduct to¬
ward Snellius can he completely justified.
Descartes would have conceived his philoso¬
phy to he disgraced if it had borrowed any ge¬
neral principle from experience, and he therefore
derived, or affected to derive, the law of refrac¬
tion from reasoning or from theory. In this
reasoning there were so many arbitrary suppo¬
sitions concerning the nature of light, and the
action of transparent bodies, that no confidence
can he placed in the conclusions deduced from
it. It is indeed quite evident that, independent¬
ly of experiment, Descartes himself could have
put no trust in it; and it is impossible not to feel
how much more it would have been for the credit
of that philosopher to have fairly confessed that
the knowledge of the law was from experiment,
and that the business of theory was to deduce
from thence some inferences with respect to the
constitution of light and of transparent bodies.
This I conceive to be the true method of philo¬
sophizing, but it is the reverse of that which
Descartes pursued on all occasions.
The weakness of his reasoning was perceived
and attacked by Fermat, who, at the same time,
was not very fortunate in the theory which he
proposed to substitute for that of his rival. The
latter had laid it down as certain, that light, of
which he supposed the velocity infinite, or the
propagation instantaneous, meets with less ob¬
struction in dense than in rare bodies, for which
reason, it is refracted toward the perpendicular,
in passing from the latter into the former. This
seemed to Fermat a very improbable supposi¬
tion, and he conceived the contrary to be true,
viz. that light in rare bodies has less obstruc¬
tion, and moves with greater velocity, than I®
dense bodies. On this supposition, and appeal¬
ing, not to physical, but to final causes, Fermat
imagined to himself that he could deduce the
true law of refraction. He conceived it to be a
fact that light moves always between two points,
so as to go from the one to the other in the least
time possible. Hence, in order to pass from a
given point in a rarer medium where it moves
faster, to a given point in a denser medium
where it moves slower, so that the time may be
a minimum, it must continue longer in the for¬
mer medium than if it held a rectilineal course;
and the bending of its path, on entering the lat¬
ter, will therefore be toward the perpendicular.
On instituting the calculus, according to his own
doctrine of maxima and minima, Fermat found,
to his surprise, that the path of the ray must be
such, that the sines of the angles of incidence
and refraction have a constant ratio to one an¬
other. Thus did these philosophers, setting out
from suppositions entirely contrary, and follow¬
ing routes which only agreed in being quite un-
philosophical and arbitrary, arrive, by a very
unexpected coincidence, at the same conclusion.
Fermat could no longer deny the law of refrac¬
tion, as laid down by Descartes; but he was less
than ever disposed to admit the justness of his
reasoning.
Descartes proceeded from this to a problem
which, though suggested by optical considera¬
tions, was purely geometrical, and in which his
researches were completely successful. It was
well known that, in the ordinary cases of re¬
fraction by spherical and other surfaces, the rays
are not collected into one point, but have their
foci spread over a certain surface, the sections
of which are the curves called caustic curves;
and that the focus of opticians is only a point m
this surface, where the rays are more condensed,
and, of course, the illumination more intense,
than in other parts of it. It is plain, however,
that if refraction is to be employed, either for
the purpose of producing light or heat, it would
be a great advantage to have all the rays which
come from the same point of an object united
accurately, after refraction, in the same point of
the image. This gave rise to an inquiry into
the figure which the superficies, separating two
DISSERTATION FOURTH.
629
transparent media of different refracting powers,
must have, in order that all the rays diverging
from a given point might, by refraction at the
said superficies, he made to converge to another
given point.1 The problem was resolved by
Descartes in its full extent j and he proved that
the curves, proper for generating such super¬
ficies by their revolution, are all comprehended
under one general character, viz. that there are
always two given points, from which, if straight
lines be drawn to any point in the curve, the
one of these, 'plus or minus, that which has a
given ratio to the other, is equal to a given line.
It is evident, when the given ratio here men¬
tioned is a ratio of equality, that the curve is a
conic section, and the two given points its two
foci. The curves, in general, are of the fourth
or the second order, and have been distinguish¬
ed by the name of the ovals of Descartes.
From this very ingenious investigation, no
practical result of advantage in the construction
of lenses has been derived. The mechanical
difficulties of working a superficies into any
figure hut a spherical one are so great, that, not¬
withstanding all the efforts of Descartes himself
and of many of his followers, they have never
been overcome; so that the great improvements
in optical instruments have arisen in a quarter
entirely different.
Descartes gave also a full explanation of the
rainbow, • as far as colour was not concerned; a
part of the problem which remained for Newton
to resolve. The path of the ray was traced, and
the angles of the incident ray, with that which
emerges after two refractions and one reflec¬
tion, were accurately determined. Descartes paid
little attention to those who had gone before him,
and, as already remarked, never once mentioned
the archbishop of Spalatro. Like Aristotle, he
seems to have formed the design of cutting off
the memory of all his predecessors; but the in¬
vention of printing had made this a far more
hopeless undertaking than it was in the days of
the Greek philosopher.
After the publication of the Dioptrics of Des¬
cartes, in 1637, a considerable interval took
place, during which optics, and indeed science
in general, made hut little progress, till the Op¬
tica Promota of James Gregory, in 1663, seemed
to put them again in motion. The author of
this work, a profound and inventive geometer,
had applied diligently to the study of optics and
the improvement of optical instruments. The
Optica Promota embraced several new inquiries
concerning the illumination and distinctness of
the images formed in the foci of lenses, and
contained an account of the reflecting telescope,
still known by the name of its author. The
consideration which suggested this instrument
was the imperfection of the images formed by
spherical lenses, in consequence of which, they
are not in plane, hut in curved surfaces. The
desire of removing this imperfection led Gregory
to substitute reflection for refraction in the con¬
struction of telescopes; and by this means, while
he was seeking to remedy a small evil, he pro¬
vided the means of avoiding a much greater one,
with which he was not yet acquainted, viz. that
which arises from the unequal refrangibility of
light. The attention of Newton was about the
same time drawn to the same subject, hut with
a perfect knowledge of the defect which he
wanted to remove. Gregory thought it neces¬
sary that the specula should be of a parabolic
figure; and the execution proved so difficult,
that the instrument, during his own life, was
never brought to any perfection. The specula
were afterwards constructed of the ordinary
spherical form, and the Gregorian telescope, till
the time of Dr Herschel, was more in use than
the Newtonian.
Gregory was Professor of Mathematics at St
Andrews, and afterwards for a short time at
Edinburgh. His writings strongly mark the
imperfect intercourse which subsisted at that
time between this country and the Continent.
Though the Optics of Descartes had been pub¬
lished twenty-five years, Gregory had not heard
of the discovery of the law of refraction, and had
found it out only by his own efforts;—happy in
being able, by the fertility of his genius, to
supply the defects of an insulated and remote
situation.
A course of lectures on optics, delivered at
1 Cartes!! Dioptrice, cap. viiL ; Geometria, lib. ii.
2 Meteora, cap. viiL
630
PRELIMINARY DISSERTATIONS.
Cambridge in 1668, by Dr Barrow, and pub¬
lished in the year following, treated of all the
more difficult questions which had occurred in
that state of the science, with the acuteness and
depth which are found in all the writings of
that geometer. This work contains some new
views in optics, and a great deal of profound
mathematical discussion.
About this time Grimaldi, a learned Jesuit,
the companion of Riccioli, in his astronomical
labours, made known some optical phenomena
which had hitherto escaped observation. They
respected the action of bodies on light, and when
compared with reflection and refraction, might
be called, in the language of Bacon’s philosophy,
crepuscular instances, indicating an action of the
same kind, but much weaker and less percep¬
tible. Having stretched a hair across a sun¬
beam, admitted through a hole in the window-
shutter of a dark chamber, he was surprised to
find the shadow much larger than the natural
divergence of the rays could have led him to
expect. Other facts of the same kind made
known the general law of the diffraction or in¬
flection of light, and showed that the rays are
acted on by bodies, and turned out of their rec¬
tilineal course, even when not in contact, but
at a measurable distance from the surfaces or
edges of such bodies. Grimaldi gave an account
of those facts in a treatise printed at Bologna
in 1665.1 *
Optics, as indeed all the branches of Natural
Philosophy, have great obligations to Huygens.
The former was among the first scientific ob¬
jects which occupied his mind; and his Diop¬
trics, though a posthumous work, is most of it
the composition of his early youth. It is writ¬
ten with great perspicuity and precision, and is
said to have been a favourite book with Newton
himself. Though beginning from the first ele¬
ments, it contains a full development of the
matters of greatest difficulty in the construction
of telescopes, particularly in what concerns the
indistinctness arising from the imperfect foci
into which rays are united by spherical lenses ;
and rules are deduced for constructing tele¬
scopes, which, though of different sizes, shall
have the same degree of distinctness, illumina¬
tion, &c. Huygens was, besides, a practical op¬
tician ; he polished lenses and constructed tele¬
scopes with his own hands, and some of his ob¬
ject-glasses were of the enormous focal distance
of ISO feet. To his Dioptrics is added a valu¬
able treatise De Formandis Vitris.
In the history of optics, particular attention
is due to his theory of light, which was first
communicated to the Academy of Sciences of
Paris, in 1678, and afterwards published, with
enlargements, in 1690.8
Light, according to this ingenious system,
consists in certain undulations communicated
by luminous bodies to the ethereal fluid which
fills all space. This fluid is composed of the
most subtile matter, is highly elastic, and the
undulations are propagated through it with great
velocity in spherical superficies proceeding from
a centre. Light, in this view of it, differs from
that of the Cartesian system, which is supposed
to be without elasticity, and to convey impres¬
sions instantaneously, as a staff does from the
object it touches to the hand which holds it.
It is not, however, in this general view that
the ingenuity of the theory appears, but in its
application to explain the equality of the angles
of incidence and reflection; and, most of all,
the constant ratio which subsists between the
sines of the angles of incidence and of refrac¬
tion. Few things are to be met with more
simple and beautiful than this last application of
the theory; but that which is most remarkable
of all is, the use made of it to explain the double
refraction of Iceland crystal. This crystal, which
is no other than the calcareous spar of mineral¬
ogists, has not only the property of refracting light
in the usual manner of glass, water, and other
transparent bodies, but it has also another power
of refraction, by which even the rays falling
perpendicularly on the surface of the crystal are
turned out of their course, so that a double
image is formed of all objects seen through these
crystals. This property belongs not only to
calcareous spar, but, in a greater or less degree,
1 Physico-Mathesis de Lumine, Coloribus, S^c. 4to.
* Traite de la Lumiere. Leyde, 1690.
dissertation fourth.
631
to all substances which are both crystallized
and transparent.
The common refraction is explained by Huy¬
gens, on the supposition that the undulations
in the luminous fluid are propagated in the form
of spherical waves. The double refraction is
explained on the supposition that the undula¬
tions of light, in passing through the calcareous
spar, assume a spheroidal form; and this hypo¬
thesis, though it does not apply with the same
simplicity as the former, yet admits of such pre¬
cision, that a proportion of the axes of the sphe¬
roids may be assigned, which will account for
the precise quantity of the extraordinary refrac¬
tion, and for all the phenomena dependent on it,
which Huygens had studied with great care, and
had reduced to the smallest number of general
facts. That these spheroidal undulations ac¬
tually exist, he would, after all, be a bold theo¬
rist who should affirm ; but, that the supposition
of their existence is an accurate expression of
the phenomena of double refraction, cannot be
doubted. When one enunciates the hypothesis
of the spheroidal undulations, he, in fact, ex¬
presses in a single sentence all the phenomena
of double refraction. The hypothesis is there¬
fore the means of representing these phenomena,
and the laws which they obey, to the imagina¬
tion or the understanding; and there is perhaps
no theory in optics, and but very few in natural
philosophy, of which more can be said. Theory,
therefore, in this instance, is merely to be re¬
garded as the expression of a general law; and
in that light, I think, it is considered by La¬
place.
To carry the theory of Huygens farther, and
to render it quite satisfactory, a reason ought to
be assigned why the undulations of the luminous
fluid are spheroidal in the case of crystals, and
spherical in all other cases. This would be to
render the generalization more complete; and
till that is done, and a connection clearly estab¬
lished between the structure of crystallized bo¬
dies and the property of double refraction, the
theory will remain imperfect. The attention
which at present is given to this most singular
and interesting branch of optics, and the great
number of new phenomena observed and classed
under the head of the Polarisation of Light, make
it almost certain that this object will be either
speedily accomplished, or that science has here
reached one of the immovable barriers by which
the circle of human knowledge is to be for ever
circumscribed.
DISSERTATION FOURTH.
PART SECOND.
FROM THE COMMENCEMENT OF NEWTON’S DISCOVERIES TO THE YEAR 1818-
In the former part of this sketch, the history
of each division of the sciences was continued
without interruption, from the beginning to the
end. During the period, however, on which I
am now to enter, the advancement of knowledge
has been so rapid, and marked by such distinct
steps, that several pauses or resting-places occur,
of which it may be advisable to take advantage.
Were the history of any particular science to be
continued for the whole of the busy interval
which this second part embraces, it would leave
the other sciences too far behind, and would
make it difficult to perceive the mutual action
by which they have so much assisted the pro¬
gress of one another. Considering some sort of
subdivision, therefore, as necessary, and observ¬
ing, in the interval which extends from the first
of Newton’s discoveries to the year 1818, three
different conditions of the Physico-Mathematical
sciences, well marked and distinguished by great
improvements, I have divided the above interval
into three corresponding parts. The first of
these, reaching from the commencement of New¬
ton’s discoveries in 1663, to a little beyond his
death, or to 1730, may be denominated, from
the men who impressed on it its peculiar charac¬
ter, the period of Newton and Leibnitz. The
second, which, for a similar reason, I call that
of Euler and D’Alembert, may be regarded
as extending from 1730 to 1780; and the third,
that of Lagrange and Laplace, from 1780 to
1818.
PERIOD FIRST.
SECTION I.
THE NEW GEOMETRY.
The seventeenth century, which had advan- scries of philosophical discoveries yet recorded
ced with such spiiit and success in combating in the history of letters. It was about to wit-
piejudice, detecting error, and establishing truth, ness, in succession, the invention of Fluxions,
vas destined to conclude with the most splendid the discovery of the Composition of Light, and
BISS. IV., PART II. ^ At
634
PRELIMINARY DISSERTATIONS.
of the Principle of Universal Gravitation, ail
three within a period of little more than twenty
years, and all three the work of the same indi-
yldukl. It is to the first of these that oui atten¬
tion at present is to he particularly directed.
The notion of Infinite Quantity had, as we
have already seen, been for some time introdu¬
ced into geometry, and having become a subject
of reasoning and calculation, had, in many in¬
stances, after facilitating the process of both,
led to conclusions from which, as if by magic,
the idea of infinity had entirely disappeared, and
left the geometer or the algebraist in possession
of valuable propositions, in which were involved
no magnitudes hut such as could he readily ex¬
hibited. The discovery of such results had in¬
creased both the interest and extent of mathe¬
matical investigation.
It was in this state of the sciences that New¬
ton began his mathematical studies, and, after a
very short interval, his mathematical discove¬
ries. 1 2 * * The book, next to the elements, which
was put into his hands, was Wallis’s Arithmetic
of Infinites, a work well fitted for suggesting new
views in geometry, and calling into activity the
powers of mathematical invention. Wallis had
effected the quadrature of all those curves in
which the value of one of the co-ordinates can
be expressed in terms of the other, without in¬
volving either fractional or negative exponents.
Beyond this point, neither his researches nor
those of any other geometer had yet reached,
and from this point the discoveries of Newton
began. The Savilian professor had himself been
extremely desirous to advance into the new re¬
gion, where, among other great objects, the quad¬
rature of the circle must necessarily he contain¬
ed ; and he made a very noble effort to pass the
barrier by which the undiscovered country ap¬
peared to he defended. He saw plainly, that if
the equations of the curves which he had squar¬
ed were ranged in a regular series, from the
simpler to the more complex, their areas would
constitute another corresponding series, the
terms of which were all known. He further re¬
marked, that, in the first of these series, the
equation to the circle itself might he introduced,
and would occupy the middle place between the
first and second terms of the series, or between
an equation to a straight line and an equation to
the common parabola. He concluded therefore,
that if, in the second series, he could interpolate
a term in the middle, between its first and se¬
cond terms, this term must necessarily he no
other than the area of the circle. But when he
proceeded to pursue this very refined and phi¬
losophical idea, he was not so fortunate; and
his attempt toward the requisite interpolation,
though it did not entirely fail, and made known
a curious property of the area of the circle, did
not lead to an indefinite quadrature of that
curve.8 Newton was much more judicious and
successful in his attempt. Proceeding on the
same general principle with Wallis, as he him¬
self tells us, the simple view which he took of
the areas already computed, and of the terms of
which each consisted, enabled him to discover the
law which was common to them all, and under
which the expression for the area of the circle,
as well as of innumerable other curves, must
needs he comprehended. In the case of the circle,
as in all those where a fractional exponent ap¬
peared, the area was exhibited in the form of an
infinite series.
The problem of the quadrature of the circle,
and of so many other curves, being thus resolv¬
ed, Newton immediately remarked, that the law
of these series was, with a small alteration, the
law for the series of terms which expresses the
root of any binomial quantity whatsoever. Thus
he was put in possession of another valuable dis¬
covery, the Binomial Theorem, and at the same
time perceived that this last was in reality, in
the order of things, placed before the other, and
afforded a much easier access to such quadratures
than the method of interpolation, which, though
the first road, appeared now neither to be the
easiest nor the most direct.
It is but rarely that we can lay hold with cer¬
tainty of the thread by which genius has been
1 He entered at Trinity College, Cambridge, in June IfiGO. The date of his first discoveries is about 1663.
2 The interpolation of Wallis failed, because he did not employ literal or general exponents. His theorem, expressing
the area of the entire circle by a fraction, of which the numerator and denominator are each the continued product of a
certain series of numbers, is a remarkable anticipation of some of Euler’s discoveries. {Calc. Int. tom. I. cap. viii.)
DISSERTATION FOURTH.
635
guided in its first discoveries. Here we are pro¬
ceeding on the authority of the author himself;
for in a letter to Oldenburg,1 * Secretary of the
Royal Society of London, he has entered into
considerable detail on this subject, adding, (so
ready are the steps ot invention to be forgotten)
that the facts would have entirely escaped his
memory, if he had not been reminded of them
by some notes which he had made at the time,
and which he had accidentally fallen on. The
whole of the letter just referred to is one of the
most valuable documents to he found in the his¬
tory of invention.
In all this, however, nothing occurs from which
it can he inferred that the method of fluxions had
yet occurred to the inventor. His discovery con¬
sisted in the method of reducing the value of?/, the
ordinate of a curve, into an infinite series of the
integer powers of x the abscissa, hy division, or
the extraction of roots, that is, hy the Binomial
Theorem; after which, the part of the area belong¬
ing to each term could he assigned hy the arith¬
metic of infinites, or other methods already known.
He has assured us himself, however, that the
great principle of the new geometry was known
to him, and applied to investigation, as early as
1665 or 1666.^ Independently of that authori¬
ty, we also know, on the testimony of Barrow,
that soon after the period j ust mentioned there
was put into his hands by Newton a manuscript
treatise,3 the same which was afterwards pub¬
lished under the title of Analysis per JEqna-
tiones Numero Terminorwn Infinitas, in which,
though the instrument of investigation is no¬
thing else than infinite series, the principle of
fluxions, if not fully explained, is at least dis¬
tinctly pointed out. Barrow strongly exhorted
his young friend to publish this treasure to the
world; hut the modesty of the author, of which
the excess, if not culpable, was certainly in the
present instance very unfortunate, prevented his
compliance. All this was previous to the year
1669; the treatise itself was not published till
1711, more than forty years after it was written.
For a long time, therefore, the discoveries of
Newton were only known to his friends; and
the first work in which he communicated any
thing to the world on the subject of fluxions was
in the first edition of the Principia^ in 1687, in
the second Lemma of the second book, to which,
in the disputes that have since arisen about the
invention of the new analysis, reference has been
so often made. The principle of the fluxionary
calculus was there pointed out, but nothing ap¬
peared that indicated the peculiar algorithm, or
the new notation, which is so essential to that
calculus. About this Newton had yet given no
information; and it was only from the second
volume of Wallis’s Works, in 1693, that it be¬
came known to the world.4 It was no less than
ten years after this, in 1704, that Newton him¬
self first published a work on the new calculus,
his Quadrature of Curves, more than twenty-
ei^1f years after it was written.
These discoveries, however, even before the
press was employed as their vehicle, could not
remain altogether unknown in a country where
the mathematical sciences were cultivated with
zeal and diligence. Barrow, to whom they were
first made known by the author himself, com¬
municated them to Oldenburg, the Secretary of
the Royal Society, who had a very extensive cor¬
respondence all over Europe. By him the series
for the quadrature of the circle were made known
to James Gregory, in Scotland, who had oc¬
cupied himself very much with the same subject.
They were also communicated to Leibnitz in Ger¬
many, who had become acquainted with Olden¬
burg in a visit which he made to England in
1673. At the time of that visit, Leibnitz was
but little conversant with the Mathematics; but
having afterwards devoted his great talents to
1 Commercium Epistolicum, No. 55.
* Quadrature of Curves, Introduction.
* Couimercium Epistohcum, No. I. II. III. &c.
that,!le had inserted in the English edition of his book, published in 1685, several extracts from Newton’s
’ ■7llSfj. multu alus lmhl notatu dignis, eo quod speraverim darissimum vxrum voluisse turn ilia, tuui alia quae apud
L.nuL '• Cum ver0 iUud nondum fecerit, libet corum nonnulla hie attingere, ne pereant." Among these last is an
and nkn nf ■ uxlonary •rl0tat'1/?n, _according to which the fluxions of flowing quantities are distinguished by points,
tom. TT n thlS .nevv alS°rit.hm, extracted from two letters of Newton, written in 1792. {Opera,
probable that it dkl *J‘nere is no evidence ot his notation having existed earlier than that date, though it be highly
636
PRELIMINARY DISSERTATIONS.
the study of that science, he was soon m a con¬
dition to make new discoveries. He invented a
method of squaring the circle, by transforming
it into another curve of an equal area, but hav¬
ing the ordinate expressed by a rational fraction
of the absciss, so that its area could be found by
the methods already known. In this way he
discovered the series, so remarkable for its sim¬
plicity, which gives the value of a circular arch
in terms of the tangent. This series he com¬
municated to Oldenburg in 1674, and received
from him in return an account of the progress
made by Newton and Gregory in the invention
of series. In 1676, Newton described his me¬
thod of quadratures at the request of Olden¬
burg, in order that it might be transmitted to
Leibnitz, in the two letters already mentioned,
as of such value, by recording the views which
guided that great geometer in his earliest, and
some of his most important discoveries. The
method of fluxions is not communicated in these
letters; nor are the principles of it in any way
suggested; though there are, in the last letter,
two sentences in transposed characters, which
ascertain that Newton was then in possession of
that method, and employed in speaking of it the
same language in which it was afterwards made
known. In the following year, Leibnitz, in
a letter to Oldenburg, introduces differentials,
and the methods of his calculus, for the first
time. This letter,1 which is very important,
clearly proves that the author was then in full
possession of the principles of his calculus, and
had even invented the algorithm and notation.
From these facts, and they are all that bear
directly on the question concerning the inven¬
tion of the infinitesimal analysis, if they be fair¬
ly and dispassionately examined, I think that no
doubt can remain that Newton was the first in¬
ventor of that analysis, which he called by the
name of Fluxions ; but that, in the communica¬
tions made by him, or his friends, to Leibnitz,
there was nothing that could convey any idea
of the principle on which that analysis was
founded, or of the algorithm which it involved.
The things stated were merely results; and
though some of those relating to the tangents of
curves might show the author to be in possession
of a method of investigation different from infi¬
nite series, yet they afforded no indication of
the nature of that method, or the principles on
which it proceeded.
In what manner Newton’s communications
in the two letters already referred to may have
acted in stimulating the curiosity, and extending,
or even directing, the views of such a man as
Leibnitz, I shall not presume to decide (nor,
even if such effect be admitted, will it take
from the originality of his discoveries); but, that
in the authenticated communications which took
place between these philosophers there was no¬
thing which could make known the nature of
the fluxionary calculus, I consider as a fact most
fully established.
Of the new or infinitesimal analysis, we
are, therefore, to consider Newton as the first
inventor, Leibnitz as the second; his disco¬
very, though posterior in time, having heen
made independently of the other, and having no
less claim to originality. It had the advantage
also of being first made known to the world;
an account of it, and of its peculiar algorithm,
having been inserted in the first volume of the
ylcta Eniditorim, in 1684. Thus, while New¬
ton’s discovery remained a secret, communicated
only to a few friends, the geometry of Leibnitz
was spreading with great rapidity over the Con¬
tinent. Two most able coadjutors, the brothers
James and John Bernoulli, joined their talents
to those of the original inventor, and illustrated
the new methods by the solution of a great Ara-
riety of difficult and interesting problems. The
reserve of Newton still kept his countrymen ig¬
norant of his geometrical discoveries; and the
first book that appeared in England on the new
geometry was that of Craig, who professedly
derived his knowledge from the writings of
Leibnitz and his friends. Nothing, however,
like rivalship or hostility between these inventors
had yet appeared; each seemed willing to admit
the originality of the other’s discoveries; and
Newton, in the passage of the Principia just re¬
ferred to, gave a highly favourable opinion on
the subject of the discoveries of Leibnitz.
1 Cummacium Episiolicuin, No. Gt».
DISSERTATION FOURTH.
637
The quiet, however, that now prevailed be¬
tween the English and German philosophers,
was clearly of a nature to he easily disturbed.
With the English was conviction, and, as we
have seen, a well-grounded conviction, that
the first discovery of the infinitesimal analysis
was the property of Newton; but the analysis
thus discovered was yet unknown to the pub¬
lic, and was in the hands of the inventor and
his friends. With the Germans there was the
conviction, also well founded, that the invention
of their countryman was perfectly original; and
they had the satisfaction to see his calculus
everywhere adopted, and himself considered all
over the Continent as the sole inventor. The
friends of Newton could not but resist this latter
claim; and the friends of Leibnitz, seeing that
their master had become the great teacher of
the new calculus, could not easily bring them¬
selves to acknowledge that he was not the first
discoverer. The tranquillity that existed under
such circumstances, if once disturbed, was not
likely to be speedily restored.
Accordingly, a remark of Fatio dc Duillier, a
mathematician, not otherwise very remarkable,
was sufficient to light up a flame which a whole
century has been hardly sufficient to extinguish.
In a paper on the line of swiftest descent, which
he presented to the Royal Society in 1699, was
this sentence: “ I hold Newton to have been
the first inventor of this calculus, and the earliest,
by several years, induced by the evidence of
facts; and whether Leibnitz, the second in¬
ventor, has borrowed any thing from the other,
I leave to the judgment of those who have seen
the letters and manuscripts of Newton.” Leib¬
nitz replied to this charge in the Leipsic Journal,
without any asperity, simply stating himself to
have been, as well as Newton, the inventor;
neither contesting nor acknowledging Newton’s
claim to priority, but asserting his own to the
first publication of the calculus.
Not long after this, the publication of New¬
ton s Quadrature of Curves, and his Enumeration
of the lines of the third order, (1705) afforded the
same journalists an opportunity of showing their
determination to retort the insinuations of Du¬
illier, and to carry the war into the country of
the enemy. After giving a very imperfect
synopsis of the first of these books, they add :
“ Ero differentiis igitur Leihnitianis D. Neictonus
adhibet, semperque adhibuit, fiuxiones; quce sunt
quamproxime utfluentium augmenta, cequalibus tem-
porisparticulis quam minimis genita; Usque, turn in
suis Principiis Naturce Mathematicis, turn in aliis
postea editis, eleganter est usus; que.madmodum
Honoratus Fabrius in sua Synopsi Geometrica
motuum progressus Cavalierianai methodo substi-
tuit.”1
In spite of the politeness and ambiguity of
tbis passage, the most obvious meaning appeared
to be, that Newton had been led to the notion
of fluxions by the differentials of Leibnitz, just
as Honoratus Fabri had been led to substitute
lhe idea ot progressive motion for the indivisibles
of Cavalieri. A charge so entirely unfounded,
so inconsistent with acknowledged facts, and so
little consonant to declarations that had former¬
ly come from the same quarter, could not but
call forth the indignation of Newton and his
friends, especially as it was known that these
journalists spoke the language of Leibnitz and
Bernoulli. In that indignation they were per¬
fectly justified; but when the minds of con¬
tending parties have become irritated in a cer¬
tain degree, it often happens that the injustice
of one side is retaliated by an equal injustice
from the opposite. Accordingly, Keili, who,
with more zeal than judgment, undertook the
defence of Newton’s claims, instead of endea¬
vouring to establish the priority of his disco¬
veries by an appeal to facts and to dates that
could be accurately ascertained, (in which he
would have been completely successful) under¬
took to prove, that the communications of New¬
ton to Leibnitz were sufficient to put the latter
in possession of the principles of the new ana¬
lysis, after which he had only to substitute the
notion of differentials for that of fluxions. In
support of a charge which it would have re¬
quired the clearest and most irresistible evidence
to justify, he had, however, nothing to offer but
equivocal facts and overstrained arguments,
such as could only convince those who were al-
1 Cammercium Ejnstolicum, No. 79: Newtoni Oj>cra, tom. IV. p. 577.
638
preliminary dissertations.
ready disposed to believe. They were, accord¬
ingly, received as sound reasoning in England,
rejected as absurd in Germany, and read with
no effect by the mathematicians of France and
Italy.
Leibnitz complained of Keill’s proceeding to
the Royal Society of London, which declined
giving judgment, but appointed a commission of
its members to draw up a full and detailed le-
port of all the communications which had passed
between Newton and Leibnitz, or their friends,
on subjects connected with the new analysis,
from the time of Collins and Oldenburg to the
date of Keill’s letter to Sir Hans Sloane in 1711,
the same that was now complained of. This re¬
port forms what is called the Commercium Epis-
iolicum ; it was published by order of the Royal
Society the year following, and contains an ac¬
count of the facts, which, though in the main
fair and just, does not give that impression of
the impartiality of the reporters which the cir¬
cumstances so imperiously demanded. Leib¬
nitz complained of this publication, and al¬
leged, that though nothing might be inserted
that was not contained in the original letters,
yet certain passages were suppressed which were
favourable to his pretensions. He threatened
an answer, which, however, never appeared.
Some notes were added to the Commercium,
which contain a good deal of asperity and un¬
supported insinuation. The JRecensio, or review
of it, inserted in the Philosophical Transactions
for 1715, though written with ability, is still
more liable to the same censure.
In the year (1713) which followed the publi¬
cation of the Commercium Epistolicum, a para¬
graph was circulated among the mathematicians
of Europe, purporting to be the judgment of a
mathematician on the invention of the new ana¬
lysis. The author was not named, but was
generally understood to be John Bernoulli, of
which, indeed, the terms in which Leibnitz
speaks of the judgment leave no room to doubt.
Bernoulli was without question well acquainted
with the subject in dispute; he was a perfect
master of the calculus; he had been one of the
great instruments of its advancement; and, ex¬
cept impartiality, possessed every requisite for a
judge. Without offence it might be said, that
he could scarcely be accounted impartial. He
had been a party in all that had happened.
Warmly attached as he was to the one side,
and greatly exasperated against the other, his
temper had been more frequently ruffled, and
his passions or prejudices more violently excited,
than those of any other individual. With all
his abilities, therefore, he was not likely to
prove the fairest and most candid judge, in a
cause that might almost be considered as his own.
His sentence, however, is pronounced in calm
and temperate language, and amounts to this,
That there is no reason to believe that the fluxion¬
ary calculus was invented before the differential.
The friends of Leibnitz hurt their own cause,
by attempting to fix on Newton a charge of pla¬
giarism, which was refuted by such a chain of
evidence, by so many dates distinctly ascertain¬
ed, and so many concessions of their own. A
candid review of the evidence led to the con¬
viction, that both Newton and Leibnitz were
original inventors. When the English mathe¬
maticians accused Leibnitz of borrowing from
Newton, they were, therefore, going much far¬
ther than the evidence authorized them, and
were mistaking their own partialities for proofs.
They maintained what was not true, but what,
nevertheless, was not physically impossible, the
discovery of Newton being certainly prior to that
of Leibnitz. The German mathematicians, on
the other hand, when they charged Newton with
borrowing from Leibnitz, were maintaining what
was not only false, but what involved an impos¬
sibility. This is the only part of the dispute, in
which any thing that could be construed into
mala fldes can be said to have appeared. I am
far, however, from giving it that construction;
men of such high character, both for integrity
and talents, as Leibnitz and Bernoulli, ought
not to be lightly subjected to so cruel an impu¬
tation. Partiality, prejudice, and passion, are
sufficient to account for much injustice, without
a decided intention to do wrong.
In the state of hostility to which matters were
now brought, the new analysis itself was had re¬
course to, as affording to either side abundant
means of annoying its adversaries, by an inex¬
haustible supply of problems, accessible to those
alone who were initiated in the doctrines, and
DISSERTATION FOURTH.
639
who could command the resources of that ana¬
lysis. The power of resolving such problems,
therefore, seemed a test whether this analysis
was understood or not. Already some questions
of this kind had been proposed in the Leipsic
Journal, not as defiances, but as exercises in the
new geometry. Such was the problem of the
Latenaria, or the curve, which a chain of uni¬
form weight makes when suspended from two
points. Tin’s had been proposed by Bernoulli
in 1690, and had been resolved by Huygens,
Leibnitz, and himself.
A question had been proposed, also, concern¬
ing the line of swiftest descent, in 1697, or
the line along which a body must descend, in
order to go from one point to another not per¬
pendicularly under it, in the least time possible.
Though a straight line be the shortest distance
between two points, it does not necessarily fol¬
low that the descent in that line will be most
speedily performed; for, by falling in a curve
that has at first a very rapid declivity, the body
may acquire in the beginning of its motion so
great a velocity, as shall carry it over a long
line in less time than it would describe a short
one, with a velocity more slowly acquired. This,
however, is a problem that belongs to a class of
questions of peculiar difficulty; and accordingly
it was resolved only by a few of the most dis¬
tinguished mathematicians. The solutions which
appeared within the time prescribed were from
Leibnitz, Newton, the two Bernoullis, and M.
de THopital. Newton’s appeared in the Philo¬
sophical Transactions without a name; but the
author was easily recognised. John Bernoulli,
on seeing it, is said to have exclaimed, Ex ungue
leonem !
The curve that has the property required is
the cycloid: Newton has given the construction,
but has not accompanied it with the analysis.
He added afterwards the demonstration of a very
curious theorem for determining the time of the
actual descent. Leibnitz resolved the problem
the same day that he received the programme in
which it was proposed.
The problem of orthogonal trajectories, as it
is called, had been long ago proposed in the Acta
Eruditorum, with an invitation to all who were
skilled in the new analysis to attempt the solu¬
tion. The problem had not, at first, met with
the attention it was supposed to deserve; but
John Bernoulli, having resumed the considera¬
tion of it, found out what appeared a very per¬
fect and very general solution; and the question
was then (1716) proposed anew by Leibnitz, for
the avowed purpose of trying the skill of the
English mathematicians. The question is,—a
system of curves described according to a known
law being given, (all the hyperbolas, for instance,
that are described between the same assymp-
totes, or all the parabolas that have the same
directrix, and that pass through the same point,
&c.) to describe a curve which shall cut them
all at right angles. This may be considered as
the first defiance professedly aimed at the Eng¬
lish mathematicians. The problem was delivered
to Newton on his return from the Mint, when
he was much fatigued with the business of the
day : he resolved it, however, the same evening;
and his solution, though without a name, is given
in the Philosophical Transactions for 1716.1
This solution, however, only gave rise to new
quarrels; for hardly any thing so excellent could
come from the one side, that it could meet with
the entire approbation of the other. Newton’s,
indeed, was rather the plan or projet of an in¬
vestigation, than an actual solution; and, in
the general view which it took of the question,
could hardly provide against all the difficulties
that might occur in the application to particular
cases. This was what Bernoulli objected to,
and affected to treat the solution as of no value.
Brook Taylor, Secretary of the Royal Society,
and well known as one of the ablest geometers
of the time, undertook the defence of it, but
concluded with using language very reprehen¬
sible, and highly improper to be directed by one
man of science against another. Having suffi¬
ciently, as he supposed, replied to Bernoulli
and his friends, he adds, “ if they are not satis¬
fied with the solution, it must be ascribed to
their own ignorance.”'* It strongly marks the
temper by which both sides were now animated,
when a man like Taylor, eminent for profound
1 Vol. XXIX. p. 399.
8 Eorum imperitiae tribuendum est.
640
PRELIMINARY DISSERTATIONS.
science, and, in general, very much disposed to
do justice to the merits of others, should so for¬
get himself as to reproach with ignorance of the
calculus one of the men who understood it the
best, and who had contributed the most to its
improvement. The irritability and prejudices of
Bernoulli admitted of no defence, and he might
very well have been accused of viewing the so¬
lution of Newton through a medium disturbed
by their action; but to suppose that he was un¬
able to understand it, was an impertinence that
could only react on the person who was guilty
of it. Bernoulli was not exemplary for his pa¬
tience ; and it will be readily believed, that the
incivility of Taylor was sufficiently ie\engcd.
It is painful to see men of science engaged in
such degrading altercation; and I should be in¬
clined to turn from so disagreeable an object, if
the bad effects of the spirit thus excited were
not such as must again obtrude themselves on
the notice of the reader.
Taylor not long after came forward with an
open defiance to the whole Continent, and pro¬
posed a problem, Omnibus geometris non Anglis,
—a problem, of course, which he supposed that
the English mathematicians alone were suffi¬
ciently enlightened to resolve. He selected one,
accordingly, of very considerable difficulty,—
the integration of a fluxion of a complicated
form; which, nevertheless, admitted of being
done in a very elegant manner, known, I be¬
lieve, at that time to very few of the English
mathematicians,—to Cotes, to himself, and per¬
haps one or two more. The selection, never¬
theless, was abundantly injudicious; for Ber¬
noulli, as long ago as 1'702, had explained the
method of integrating this, and such like for¬
mulas, both in the Paris Memoires and in the
Leipsic Ads. The question, accordingly, was
no sooner proposed than it was answered in a
manner the most clear and satisfactory; so the
defiance of Taylor only served to display the
address and augment the triumph of his adver¬
sary.
The last and most unsuccessful of these chal¬
lenges was that of Keill, of whose former ap¬
pearance in this controversy we have already
had so much more reason to commend the zeal
than the discretion. Among the problems in
the mixed mathematics which had excited most
attention, and which seemed best calculated to
exercise the resources of the new analysis, was
the determination of the path of a projectile in
a medium which resists proportionally to the
square of the velocity, that being nearly the law
of the resistance which the air opposes to bodies
moving with great velocity. The resistance of
fluids had been treated of by Newton in the
second book of the Principia, and he had inves¬
tigated a great number of curious and import¬
ant propositions relative to its effects. He had
considered some of the simpler laws of resist¬
ance; but of the case just mentioned he had
given no solution, and, after approaching as
near as possible to it on all sides, had with¬
drawn without making an attack. A problem
so formidable was not likely to meet with many
who, even in the more improved state at which
the calculus had now arrived, could hope to
overcome its difticulties. Whether Keill had
flattered himself that he could resolve the pro¬
blem, or had forgotten, that when a man pro¬
poses a question of defiance to another, he ought
to be sure that he can answer it himself, may
be doubted; but this is certain, that, without
the necessary preparation, he boldly challenged
Bernoulli to produce a solution.
Bernoulli resolved the question in a very
short time, not only for a resistance propor¬
tional to the square, but to any power whatso¬
ever of the velocity; and by the conditions which
he affixed to the publication of his solution, took
care to expose the weakness of his antagonist.
He repeatedly offered to send his solution to a
confidential person in London, providing Keill
would do the same. Keill never made any re¬
ply to a proposal so fair, that there could only
be one reason for declining it. Bernoulli, of
course, exulted over him cruelly, breaking out
in a torrent of vulgar abuse, and losing sight of
every maxim of candour and good taste.
Such, then, were the circumstances under
which the infinitesimal analysis,—the greatest
discovery ever made in the mathematical sci¬
ences,—was ushered into the world. Every¬
where, as it became known, it enlarged the
views, roused the activity, and increased the
power of the geometer, while it directed the
DISSERTATION FOURTH.
641
warmest sentiments of his gratitude and admi¬
ration toward the great inventors. In one re¬
spect only its effects were different from those
which one would have wished to see produced.
It excited jealousy between two great men who
ought to have been the friends of one another,
and disturbed in both that philosophical tran¬
quillity of mind, for the loss of which even
glory itself is scarcely an adequate recompense.
In order to form a correct estimate of the
magnitude and value of this discovery, it may
be useful to look back at the steps by which the
mathematical sciences had been prepared for it.
When we attempt to trace those steps to their
origin, we find the principle of the infinitesimal
analysis making its first appearance in the me¬
thod of exhaustions, as exemplified in the writ¬
ings of Euclid and Archimedes. These geo¬
meters observed, and, for what we know, were
the first to observe, that the approach which
a rectilineal figure may make to one that is
curvilineal, by the increase of the number of its
sides, the diminution of their magnitude, and a
certain enlargement of the angles they contain,
may be such that the properties of the former
shall coincide so nearly with those of the latter,
that no real difference can be supposed between
them without involving a contradiction; and it
was in ascertaining the conditions of this ap¬
proach, and in showing the contradiction to be
unavoidable, that the method of exhaustions
consisted. The demonstrations were strictly
geometrical, but they were often complicated,
always indirect, and of course synthetical, so
that they did not explain the means by which
they had been discovered.
At the distance of more than two thousand
years, Cavalieri advanced a step farther, and,
by the sacrifice of some apparent, though of no
real accuracy, explained, in the method of indi¬
visibles, a principle which could easily be made
to assume the more rigid form of exhaustions.
This was a very important discovery: though
the process was not analytical, the demonstra¬
tions were direct, and, when applied to the same
subjects, led to the same conclusions which the
ancient geometers had deduced. By an indirect
proof also, such as those geometers had adopted,
it could always be shown that an absurdity fol¬
lowed from supposing the results deduced from
the method of indivisibles to be other than rigo¬
rously true.
The method of Cavalieri was improved and
extended by a number of geometers of great
genius who followed him ; Torricelli, Roberval,
Fermat, Huygens, Barrow, who all observed the
great advantage that arose from applying the
general theorems concerning variable quantity
to the cases where the quantities approached to
one another infinitely near, that is, nearer than
within any assigned difference. There was,
however, as yet, no calculus adapted to these re¬
searches, that is, no general method of reasoning
by help of arbitrary symbols.
But we must go back a step in point of time,
if we would trace accurately the history of this
last improvement. Descartes, as has been shown
in the former part of this outline, made a great
revolution in the mathematical sciences, by ap¬
plying algebra to the geometry of curves; or,
more generally, by applying it to express the re¬
lations of variable quantity. This added in¬
finitely to the value of the algebraic analysis,
and to the extent of its investigations. The
same great mathematician had observed the ad¬
vantage that would be gained in the geometry
of curves, by considering the variable quantities
in one state of an equation as differing infinitely
little from the corresponding quantities in an¬
other state of the same equation. By means
grounded on this he had attempted to draw tan¬
gents to curves, and to determine their curva¬
ture ; but it is seldom the destination of nature
that a new discovery should be begun and per¬
fected by the same individual; and, in these at¬
tempts, though Descartes did not entirely fail,
he cannot be considered as having been suc¬
cessful.1
At last came the two discoverers, Newton and
Leibnitz, who completely lifted up the veil which
their predecessors had been endeavouring to draw
aside. They plainly saw, as Descartes indeed
had done in part, that the infinitely small vari¬
ations of the ordinate and absciss are closely con-
4 M
DISS. IV., PART II.
Dissertation Fourth, Part i. p. 560.
642
PRELIMINARY DISSERTATIONS.
nected with many properties of the curve, which
have hut a very remote dependence on the ordi¬
nates and abscissae themselves. Hence they in¬
ferred, that to obtain an equation expressing
the relations of these variations to one another,
was to possess the most direct access to the
knowledge of those properties. They observed
also, that when an equation of this kind was
deduced from the general equation, it admitted
of being brought to great simplicity, and of
being resolved much more readily than the
other. In effect, it assumed the form of a
simple equation; hut, in order to make this
deduction in the readiest and most distinct way,
the introduction of new symbols, or of a new
algorithm, was necessary, the invention of which
could cost hut little to the creative genius of the
men of whom I now speak. They appear, as
has been already shown, to have made their dis¬
coveries separately;—Newton first,—Leibnitz
afterwards, at a considerable interval, yet the
earliest, by several years, in communicating his
discoveries to the world.
Thus, though there had been for ages a gra¬
dual approach to the new analysis, there were in
that progress some great and sudden advances
which elevated those who made them to a much
higher level than their predecessors. A great
number of individuals co-operated in the work;
hut those who seem essential, and in the direct
line of advancement, are Euclid, Cavalieri, Des¬
cartes, Newton, and Leibnitz. If any of the
others had been wanting, the world would have
been deprived of many valuable theorems, and
many collateral improvements, hut not of any
general method essential to the completion of
the infinitesimal analysis.
The views, however, of this analysis taken
by the two inventors were not precisely the
same. Leibnitz, considering the differences of
the variable quantities as infinitely small, con¬
ceived that he might reject the higher powers
of those differences without any sensible error;
so that none of those powers but the first re¬
mained in the differential equation finally ob¬
tained. The rejection, however, of the higher
powers of the differentials was liable to objec¬
tion, for it had the appearance of being only an
approximation, and did not come up to the per¬
fect measure of geometrical precision. The
analysis, thus constituted, necessarily divided
itself into two problems: the first is,—having
given an equation involving two or more vari¬
able quantities, to find the equation expressing
the relation of the differentials, or infinitely
small variations of those quantities : the second
is the converse of this;—having given an equa¬
tion involving two or more variable quantities,
and their differentials, to exterminate the differ¬
entials, and so to exhibit the variable quantities
in a finite state. This last process is called in¬
tegration in the language of the differential ana¬
lysis, and the finite equation obtained is called
the integral of the given differential equation.
Newton proceeded in some respects different¬
ly, and so as to preserve his calculus from the
imputation of neglecting or throwing away any
thing merely because it was small. Instead of
the actual increments of the flowing or variable
quantities, he introduced what he called the
fluxions of those quantities,—meaning, by flux¬
ions, quantities which had to one another the
same ratio which the increments had in their ul¬
timate or evanescent state. He did not reject
quantities, therefore, merely because they were
so small that he might do so without committing
any sensible error, but because he must reject
them, in order to commit no error whatsoever.
Fluxions were, with him, nothing else than mea¬
sures of the velocities with which variable or
flowing quantities were supposed to be generated;
and they might he of any magnitude, providing
they were in the ratio of those velocities, or,
which is the same, in the ratio of the nascent or
evanescent increments.1 The fluxions, there¬
fore, and the flowing quantities or fluents of
Newton, correspond to the differentials and the
sums or integrals of Leibnitz; and though the
symbols which denote fluxions are different from
those used to express differentials, they answer
1 “ I consider mathematical quantities in this place, not as consisting of small parts, but as described by a continued mo¬
tion. Lines are described, and thereby generated, not by the apposition of parts, but by the continued motion of points;
superficies by the motion of lines,” &c. {Quadrature of Curves, Introduction.)
DISSERTATION FOURTH.
643
precisely the same purpose. The fluxionary and
differential calculus may therefore be considered
as two modifications of one general method, aptly
distinguished by the name of the infinitesimal
analysis.
By the introduction of this analysis, the do¬
main of the mathematical sciences was incre¬
dibly enlarged in every direction. The great
improvement which Descartes had made by the
application of algebraic equations to define the
nature of curve lines was now rendered much
more efficient, and carried far beyond its origi¬
nal boundaries. From the equation of the curve
the new analysis could deduce the properties of
the tangents, and, what was much more diffi¬
cult, could go back from the properties of the
tangents to the equation of the curve. From
the same equation, it was able to determine the
curvature at every point; it could measure the
length of any portion of the curve or the area
corresponding to it. Nor was it only to alge¬
braic curves that those applications of the calcu¬
lus extended, but to curves transcendental and
mechanical, as in the instances of the catenaria,
the cycloid, the elastic curve, and many others.
The same sort of research could be applied to
curve surfaces described according to any given
law, and also to the solids contained by them.
The problems which relate to the maxima and
minima, or the greatest and least values of vari¬
able quantities, are among the most interesting
in the Mathematics: they are connected with
the highest attainments of wisdom and the great¬
est exertions of power; and seem like so many
immovable columns erected in the infinity of
space, to mark the eternal boundary which se¬
parates the regions of possibility and impossi¬
bility from one another. For the solution of
these problems, a particular provision seemed
to be made in the new geometry.
When any function becomes either the great¬
est or the least, it does so by the velocity of its
increase or of its decrease ceasing entirely, or,
in the language of algebra, becoming equal to
nothing. But when the velocity with which the
function varies becomes nothing, the fluxion
which is proportional to that velocity must be¬
come nothing also. Therefore, it is only neces¬
sary to take the fluxion of the given function,
and by supposing it equal to nothing, an equa¬
tion will be obtained in finite terms, (for the
fluxion will entirely disappear) expressing the
relation of the quantities when the function as¬
signed is the greatest or the least possible.
Another kind of maximum or minimum,
abounding also in interesting problems, is more
difficult by far than the preceding, and, when
taken generally} seems to be only accessible to
the new analysis. Such cases occur when the
function of the variable quantities which is to
be the greatest or the least is not given, but is
itself the thing to be found; as when it is pro¬
posed to determine the line by which a heavy
body can descend in the least time from one
point to another. Here the equation between
the co-ordinates of the curve to be found is, of
course, unknown, and the function of those co¬
ordinates, which denotes the time of descent,
cannot therefore be algebraically expressed, so
that its fluxion cannot be taken in the ordinary
way, and thus put equal to nothing. The for¬
mer rule, then, is not applicable in such cases,
and it is by no means obvious in what manner
this difficulty is to be overcome. The general
problem exercised the ingenuity of both the
Bernoullis, as it has since done of many other
mathematicians of the greatest name. As there
are in such problems always two conditions, ac¬
cording to the first of which a certain property
is to remain constant, or to belong to all the in¬
dividuals of the species, and, according to the
second, another property is to be the greatest or
the least possible; and as, in some of the simplest
of such questions,1 the constant quantity is the
circumference or perimeter of a certain curve,
so problems of this kind have had the name of
Isoperimetrical given them; a term which has
thus come to denote one of the most curious and
difficult subjects of mathematical investigation.
The new analysis, especially according to the
The most simple problem of the kind is strictly and literally isoperimetrical, viz. of all curves having the same perimeter,
to lind that which has the greatest area. Elementary geometry had pronounced this curve to be the circle long before
lere was any idea of an entire class of problems characterized by similar conditions. Vide Pap pi Aiexandrini Collect. Math.
kb. v. prop. 2. &c. 1
644
PRELIMINARY DISSERTATIONS.
view taken of it by Newton, is peculiarly ad¬
apted to physical researches, as the hypothesis
of quantities being generated by continued mo¬
tion comes there to coincide exactly with the
fact. The momentary increments or the fluxions
represent so precisely the forces by which the
changes in nature are produced, that this doc¬
trine seemed created for the express purpose of
penetrating into the interior of things, and tak¬
ing direct cognizance of those animating powers
which, by their suhtilty, not only elude the ob¬
servation of sense, hut the ordinary methods of
geometrical investigation. The infinitesimal
analysis alone affords the means of measuring
forces, when each acts separately, and instan¬
taneously under conditions that can he accurate¬
ly ascertained. In comparing the effects of con¬
tinued action, the variety of time and circum¬
stance, and the continuance of effects after their
causes have ceased, introduce so much uncer¬
tainty, that nothing hut vague and unsatisfac¬
tory conclusions can he deduced. The analysis
of infinites goes directly to the point; it mea¬
sures the intensity or instantaneous effort of the
force, and, of course, removes all those causes
of uncertainty which prevailed when the results
of continued action could alone be estimated. It
is not even by the effects produced in a short
time, but by effects taken in their nascent or
evanescent state, that the true proportion of causes
must be ascertained.
Thus, though the astronomers had proved that
the planets describe ellipses round the sun as the
common focus, and that the line from the sun to
each planet sweeps over areas proportional to
the time,—had not the geometer resolved the
elliptic motion into its primary elements, and
compared them in their state of evanescence, it
would never have been discovered that these
bodies gravitate to the sun with forces which are
inversely as the square of their distances from
the centre of that luminary. Thus, fortunately,
the first discovery of Newton was the instrument
which was to conduct him safely through all the
intricacies of his future investigations.
The calculus, as already remarked, necessari¬
ly divides itself into two branches; one which,
from the variable quantities, finds the relation of
their fluxions or differentials; another which,
from the relation of these last, investigates the
relation of the variable quantities themselves.
The first of these problems is always possible,
and, in general, easy to be resolved; the second
is not always possible, and when possible, is
often very difficult, but in various degrees, ac¬
cording to the manner in which the differentials
and the variable quantities are combined with
one another.
If the function into which the differential
stands multiplied consist of a single term, or an
aggregate of terms, in each of which the vari¬
able quantity is raised to a power expounded
by a number positive, negative, or fractional,
the integration can be effected with ease, either
in algebraic or logarithmic terms ; and the cal¬
culus had not been long known before this pro¬
blem was completely resolved.
The second case of this first division is,-—when
the given function is a fraction having a binomial
or multinomial denominator, the terms of which
contain any powers whatever of the variable
magnitude, but without involving the radical
sign. If the denominator contain only the sim¬
ple power of the variable quantity, the integral
is easily found by logarithms ; if it be complex,
it must be resolved either into simple or qua¬
dratic divisors, which, granting the solution of
equations, is always possible, at least by ap¬
proximation, and the given fraction is then
found equal to an aggregate of simple fractions,
having these divisors for their denominators,
and of which the fluents can always be exhibit¬
ed in algebraic terms, or in terms of logarithms
and circular arches. This very general and im¬
portant problem was resolved by J. Bernoulli
as early as the year 1702.
The denominator is in this last case supposed
rational; hut if it be irrational, the integration
requires other means to be employed. Here
Leibnitz and Bernoulli both taught how, by
substitutions, as in Diophantine problems, the
irrationality might he removed, and the integra¬
tion of course reduced to the former case. New¬
ton employed a different method, and, in his
Quadrature of Curves, found the fluents, by com¬
paring the given fluxion with the formulas im¬
mediately derived from the expression of circu¬
lar or hyperbolic areas. The integrations of
DISSERTATION FOURTH.
645
these irrational formulae, whichever of the me¬
thods be employed, often admit of being effected
with singular elegance and simplicity; but a
general integration of all the formulae of this
kind, except by approximation, is not yet with¬
in the power of analysis.
The second general division of the problem
of integration, viz. when the two variable quan¬
tities and their differentials are mixed together
on each side pf the equation, is a more difficult
subject of inquiry than the preceding. It may
indeed happen that an equation, which at first
presents itself under this aspect, can, by the
common rules of algebra, have the quantities
so separated, that on each side of the sign of
equality there shall be but one variable quan¬
tity with its fluxion; and when this is done, the
integration is reduced to one of the cases al¬
ready enumerated.
When such separation cannot be made, the
problem is among the most difficult which the
infinitesimal analysis presents, at the same time
that it is the key to a vast number of interest¬
ing questions both in the pure and the mixed
mathematics. The two Bernoullis applied them¬
selves strenuously to the elucidation of it; and
to them we owe all the best and most accurate
methods of resolving such questions which ap¬
peared in the early history of the calculus, and
which laid the foundation of so many subse¬
quent discoveries. This is a fact which cannot
be contested; and it must be acknowledged also,
that on the same subject the writings of the
English mathematicians were then, as they con¬
tinue to be at this day, extremely defective. New¬
ton, though he had treated of this branch of the
infinitesimal analysis with his usual ingenuity
and depth, had done so only in his work on
Fluxions, which did not see the light till several
years after his death, when, in 1736, it appear¬
ed in Colson’s Translation. But that work, even
bad it come into the hands of the public in the
author’s lifetime, would not have remedied the
defect of which I now speak. When the fluxion¬
ary equation could not be integrated by the
simplest and most elementary rules, Newton had
always recourse to approximations by infinite
series, in the contrivance of which he indeed
displayed great ingenuity and address. But an
approximation, let it be ever so good, and con¬
verge ever so rapidly, is always inferior to an
accurate and complete solution, if this last pos¬
sess any tolerable degree of simplicity. The
series which affords the approximation cannot
converge always, or in all states of the variable
quantity; and its utility, on that account, is so
much limited, that it can hardly lead to any
general result. Besides, it does not appear that
these series can always be made to involve the
arbitrary or indeterminate quantity, without
which no fluent can be considered as complete.
For these reasons, such approximations should
never be resorted to till every expedient has
been used to find an accurate solution. To this
rule, however, Newton’s method does not con¬
form, but employs approximation in cases where
the complete integral can be obtained. The
tendency of that method, therefore, however
great its merit in other respects, was to give a
direction to research which was not always the
best, and which, in many instances, made it fall
entirely short of the object it ought to have at¬
tained. It is true that many fluxionary equa¬
tions cannot be integrated in any other way;
but by having recourse to it indiscriminately,
we overlook the cases in which the integral can
be exactly assigned. Accordingly, Bernoulli,
by following a different process, remarked entire
classes of fluxionary or differential equations,
that admitted of accurate integration. Thus he
found, that differential equations, if homoge¬
neous, 1 however complicated, may always have
the variable quantities separated, so as to come
under one of the simpler forms already enume¬
rated. By the introduction, also, of exponential
equations, which had been considered in England
as of little use, he materially improved this
branch of the calculus.
To all these branches of analysis we have still
another to add of indefinite extent, arising out
of the consideration of the fluxions or differen¬
tials of the higher orders, each of these orders
1 Homogeneous equations, in the differential calculus, are those in which the sum of the exponents of the variable quanti¬
ties is the same in all the terms.
646
preliminary dissertations.
being deduced from the preceding, just as first
fluxions are from the variable quantities to which
they belong. To understand this, conceive the
successive values of the first fluxions of any va¬
riable quantity to constitute a new series of
variable quantities flowing with velocities, the
measures of which form the fluxions of the se¬
cond order, from which, in the same manner,
are deduced fluxions of the third and of still
higher orders. The general principles are the
same as in the fluxions of the first order, but
the difficulties of the calculus are greater, par¬
ticularly in the integrations; for, to rise from
second fluxions to the variable quantities them¬
selves, two integrations are necessary; from third
fluxions, three; and so on.
The tract which first made known the new
analysis was that of Leibnitz, published, as al¬
ready remarked, in the first volume of the Acta
Eruditonm for 1684, where it occupies no more
than six pages,1 2 and is the work of an author
not yet become very familiar with the nature of
his own invention. It was sufficient, however,
to explain that invention to mathematicians;
but, nevertheless, some years elapsed before it
drew much attention. The Bernoullis were the
first who perceived its value, and made them¬
selves masters of the principles and methods
contained, or rather suggested, in it. Leibnitz
published many other papers in the Acta Erudi-
torum and the journals of the times, full of ori¬
ginal views and important hints, thrown out
very briefly, and requiring the elucidations which
his friends just mentioned were always so will¬
ing and so able to supply. The number of li¬
terary and scientific objects which divided the
attention of the author himself was so great,
that he had not time to bestow on the illustra¬
tion and development of the most important of
his own discoveries; and the new analysis, for
all that he has taught, would have been very
little known, and very imperfectly unfolded, if
the two excellent geometers just named had not
come to his assistance. Their tracts were also,
like his, scattered in the different periodic works
of that time; and several years elapsed before
any elementary treatise explained the general
methods, and illustrated them by examples. The
first book in which this was done, so far at least
as concerned the differential or direct calculus,
was the Analyse des injiniment Petits of the Mar¬
quis de 1’Hopital, published in 1696; a work of
great merit, which did much to diffuse the know¬
ledge of the new analysis. It was well received
at that time, and has maintained its character
to the present day. The author, a man of ge¬
nius, indefatigable and ardent in the pursuits of
science, had enjoyed the viva voce instructions
of John Bernoulli, on the subject of the new
geometry, and therefore came forward with
every possible advantage.
It was long after this before the works of the
Bernoullis were collected together, those of
James in two quarto volumes, and of John in
four.® In the third of these last volumes is a
tract of considerable length, with the title of
Lectiones de Methodo Integralium, written in 1691
and 1692, for the use of M. de I’Hopital, to
whose book on the Differential Calculus it seems
to have been intended as a sequel. It is a work
of great merit; and affords a distinct view of
many of the most general methods of integra¬
tion, with their application to the most interest¬
ing problems; so that, though the earliest trea¬
tise on that subject, it remains at this day one
of the best compends of the new analysis of
which the mathematical world is in possession.
Indeed the whole of the volumes just referred
to are highly interesting, as containing the ori¬
ginal germs of the new analysis, and as being
the work of men always inspired by genius,
sometimes warmed by opposition, and generally
animated by the success which accompanied
their researches.
But we must now look at the original works
of the earliest inventor. Newton, besides his
letters published in the Commercium Epistolicum,
is the author of three tracts on the new ana¬
lysis that have all been occasionally mentioned.
None of them, however, appeared nearly so soon
as a great number of the pieces which have just
been enumerated. The Quadrature of Curves,
1 Nova Mr.tlwdus pro Maximis et Minimis, See. : Leibnitii Opera, tom. III. p. 167-
2 Those of James were published at Geneva in 1744 ; of John, at Lausanne and Geneva m 1742.
DISSERTATION FOURTH.
647
written as early as 1665 or 1666, did not appear
till 1704; and though it he a treatise of great
value, and containing very important and very
general theorems concerning the quadrature of
curves, it must be allowed that it is not well
adapted to make known the spirit and the views
of the infinitesimal analysis. After a short in¬
troduction, which is indeed analytical, and which
explains the idea of a fluxion with great brevity
and clearness, the treatise sets out with pro¬
posing to find any number of curves that can
be squared; and here the demonstrations be¬
come all synthetical, without any thing that may
be properly called analytical investigation. By
synthetical demonstrations I do not mean rea¬
sonings where the algebraic language is not used,
but reasonings, whatever language be employed,
where the solution of the proposed question is
first laid down, and afterwards demonstrated
to be true. Such is the method pursued through¬
out this work; and it is wonderful how many
valuable conclusions concerning the areas of
curves, and their reduction to the areas of the
circle and hyperbola, are in that manner de¬
duced. But though truths can be very well
conveyed in the synthetical way, the methods of
investigating truth are not communicated by it,
nor the powers of invention directed to their
proper objects. As an elementary treatise on the
new analysis, the Quadrature of Curves is there¬
fore imperfect, and not calculated, without great
study, to give to others any portion of the power
which the author himself has exerted. The pro¬
blem of finding fluents, though it be that on
which the whole quadrature of curves depends,
is entirely kept out of view, and never once pro¬
posed in the course of a work which, at the
same time, is full of the most elaborate and pro¬
found reasonings.
Newton had a great fondness for the synthe¬
tical method, which is apparent even in the most
analytical of his works. In his Fluxions, when
he is treating of the quadrature of curves, he
says, “ After the area of a curve has been found
and constructed, we should consider about the
demonstration of the construction, that, laying
aside all algebraical calculation as much as may
be, the theorem may be adorned and made ele¬
gant, so as to become fit for public view.”1
This is followed by two or three examples, in
which the rule here given is very happily illus¬
trated. When the analysis of a problem re¬
quires, like the quadrature of curves, the use of
the inverse method of fluxions, the reversion of
that analysis, or the synthetical demonstration,
must proceed by the direct method, and there¬
fore may admit of more simplicity than the
others, so as, in the language of the above pas¬
sage, to be easily adorned and made elegant.
The book of Fluxions is, however, an excel¬
lent work, entering very deeply into the na¬
ture and spirit of the calculus,—illustrating its
application by well-chosen examples,—and only
failing, as already said, by having recourse, for
finding the fluents of fluxionary equations, too
exclusively to the method of series, without
treating of the cases in which exact solutions
can be obtained.
Of the works that appeared in the early stages
of the calculus, none is more entitled to notice
than the Flarmonia Mensurarum of Cotes. The
idea of reducing the areas of curves to those of
the circle and hyperbola, in those cases which
did not admit of an accurate comparison with
rectilineal spaces, had early occurred to Newton,
and was very fully exemplified in his Quadra¬
ture of Curves. Cotes extended this method:—
his work appeared in 1722, and gave the rules
for finding the fluents of fractional expressions,
whether rational or irrational, greatly general¬
ized and highly improved by means of a pro¬
perty of the circle discovered by himself, and
justly reckoned among the most remarkable pro¬
positions in geometry. It is singular that a
work so profound and so useful as the Flarmo¬
nia Mensurarum should never have acquired,
even among the mathematicians of England, the
popularity which it deserves; and that, on the
Continent, it should be very little known, even
after the excellent commentary and additions of
Bishop Walmesley. The reasons perhaps are,
that, in many parts, the work is obscure; that
it does not explain the analysis which must have
led to the formula contained in the tables; and
1 Newton’s Fluxions, Colson’s Translation, p. 116, sect. 107.
648
PRELIMINARY DISSERTATIONS.
that it employs an unusual language and nota¬
tion, which, though calculated to keep in view
the analogy between circular and hypeiholic
areas, or between the measures of angles and of
ratios, do not so readily accommodate themsel'v es
to the business of calculation as those which aie
commonly in use. Demoivre, a very skilful and
able mathematician, improved the method of
Cotes, and explained many things in a manner
much more clear and analytical than had hither¬
to been done.1
Another very original and profound writer of
this period was Brook Taylor, who has already
been often mentioned, and who, in his Method
of Increments, published in 1715, added a new
branch to the analysis of variable quantity.
According to this method, quantities are sup¬
posed to change, not by infinitely small, hut by
finite increments, or such as may he of any
magnitude whatever. There are here, there¬
fore, as in the case of fluxions or differentials,
two general questions: A function of a variable
quantity being given, to find the expression for
the finite increment of that function, the incre¬
ment of the variable quantity itself being a finite
magnitude. This corresponds to the direct me¬
thod of fluxions; the other question corresponds
to the inverse, viz. A function being given con¬
taining variable quantities, and their increments
any way combined, to find the function from
which it is derived. The author has considered
both these problems, and in the solution of the
second, particularly, has displayed much ad¬
dress. He has also made many ingenious appli¬
cations of this calculus, both to geometrical and
physical questions, and, above all, to the sum¬
mation of series,—a problem for the solution of
which it is peculiarly adapted.
Taylor, however, was more remarkable for
the ingenuity and depth, than for the perspi¬
cuity of his writings. Even a treatise on Per¬
spective, of which he is the author, though in
other respects excellent, has always been com¬
plained of as obscure; and it is no wonder if,
on a new subject, and one belonging to the
higher geometry, his writings should be still
more exposed to that reproach. This fault was
removed, and the whole theory explained with
great clearness, by M. Nicole, of the Academy of
Sciences of Paris, in a series of Memoires from
the year 1717 to 1727.
A single analytical formula in the Method of
Increments has conferred a celebrity on its au¬
thor, which the most voluminous works have
not often been able to bestow. It is known by
the name of Taylor’s Theorem, and expresses
the value of any function of a variable quantity
in terms of the successive orders of increments,
whether finite or infinitely small. If any one
proposition can be said to comprehend in it a
whole science, it is this: for from it almost
every truth and every method of the new ana¬
lysis may be deduced. It is difficult to say
whether the theorem does most credit to the
genius of the author, or the power of the lan¬
guage which is capable of concentrating such a
vast body of knowledge in a single expression.
Without an acquaintance with algebra, it is im¬
possible, I believe, to conceive the manner in
which this effect is produced.
By means of its own intrinsic merit, and the
advantageous display of it made in the works
now enumerated, the new analysis, long before
the expiration of the period of which I am here
treating, was firmly established all over Europe.
It did not, however, exist everywhere in the
same condition, nor under the same form; with
the British and Continental mathematicians, it
was referred to different origins; it was in dif¬
ferent states of advancement; the notation and
some of the fundamental ideas were also differ¬
ent. The authors communicated little with one
another, except in the way of defiance or re¬
proach ; and, from the angry or polemical tone
which their speculations often assumed, one
could hardly suppose that they were pursuing
science in one of its most abstract and incorpo¬
real forms.
Though the algorithm employed, and the books
consulted on the new analysis, were different,
the mathematicians of Britain and of the Conti¬
nent had kept pace very nearly with one another
during the period now' treated of, except in one
branch, the integration of differential or of
1 Demoivre, Miscellanea Analytica. See also the work of an anonymous author, Epistola ad Amicum de Cotesii Inventis.
DISSERTATION FOURTH.
649
fiuxional equations. In this, our countrymen
had fallen considerably behind, as has been al¬
ready explained; and the distance between them
and their brethren on the Continent continued
to increase, just in proportion to the number
and importance of the questions, physical and
mathematical, which were found to depend on
these integrations. The habit of studying only
our own authors on these subjects, produced at
first by our admiration of Newton and our dis¬
like to his rivals, and increased by a circum¬
stance very insignificant in itself, the diversity
of notation, prevented us from partaking in the
pursuits of our neighbours, and cut us off in a
great measure from the vast field in which the
genius of France, of Germany, and Italy, was
exercised with so much activity and success.
Other causes may have united in the produc¬
tion of an effect which the mathematicians of
this country have had much reason to regret;
but the evil had its origin in the spirit of jea¬
lousy and opposition, which arose from the con¬
troversies that have just passed under our re¬
view. The habits so produced continued long
after the spirit itself had subsided.
It must not be supposed that so great a revo¬
lution in science as that which was made by
the introduction of the new analysis could be
brought about entirely without opposition, as in
every society there are some who think them¬
selves interested to maintain things in the con¬
dition wherein they have found them. The con¬
siderations are indeed sufficiently obvious, which,
in the moral and political world, tend to pro¬
duce this effect, and to give a stability to human
institutions, often so little proportionate to their
real value or to their general utility. Even in
matters purely intellectual, and in which the
abstract truths of arithmetic and geometry seem
alone concerned, the prejudices, the selfishness,
or vanity of those who pursue them, not unfre-
quently combine to resist improvement, and of¬
ten engage no inconsiderable degree of talent in
drawing back, instead of pushing forward, the
machine of science. The introduction of me¬
thods entirely new must often change the rela¬
tive place of the men engaged in scientific pur¬
suits ; and must oblige many, after descending
from the stations they formerly occupied, to take
a lower position in the scale of intellectual ad¬
vancement. The enmity of such men, if they
be not animated by a spirit of real candour and
the love of truth, is likely to be directed against
metbods by which their vanity is mortified, and
their importance lessened. Though such changes
as this must have everywhere accompanied the
ascendency acquired by the calculus, for the
credit of mathematicians it must be observed,
that no one of any considerable eminence has
had the misfortune to enrol his name among the
adversaries of the new science; and that Huy¬
gens, the most distinguished and most profound
of the older mathematicians then living, was
one of the most forward to acknowledge the ex¬
cellence of that science, and to make himself
master of its rules, and of their application.
Nevertheless, certain adversaries arose suc¬
cessively in Germany, France, and England, the
countries in which the new methods first be¬
came known.
Nieuwentyt, an author commendable as a na¬
turalist, and as a writer on morals, but a very
superficial geometer, aimed the first blow at the
Differential Calculus. He objected to the ex¬
planation of Leibnitz, and to the notion of quan¬
tities infinitely small.1 It seemed as if he were
unwilling to believe in the reality of objects
smaller than those discovered by his own micro¬
scope, and were jealous of any one who should
come nearer to the limit of extension than he
himself had done. Leibnitz thought his objec¬
tions not undeserving of a reply; but the reply
was not altogether satisfactory. A second was
given with better success; and afterwards Her¬
mann and Bernoulli each severally defeated an
adversary, who was but very ill able to contend
with either of them.
Soon after this, the calculus had to sustain an
attack from two French academicians, which
drew more attention than that of the Dutch
naturalist. One of these, Rolle, was a mathe¬
matician of no inconsiderable acquirement, but
1 Republished Analysis Infimtorum at Amsterdam, in 1695; and another tract, Consider ationcs circa Calculi Differentialis
j rineipia^ in the year following. This last was answered by Hermann.
DIS8. IV., PART II. 4 Ar
650
PRELIMINARY DISSERTATIONS.
whose chief gratification consisted in finding out
faults in the works of others. He founded his
objections to the differential calculus, not on the
score of principles or of general methods, but on
certain cases which he had sought out with great
industry, in which those methods seemed to him
to lead to false and contradictory conclusions.
On examination, however, it turned out, that in
every one of those instances the error was en¬
tirely his own; that he had misapplied the rules ;
and that his eagerness to discover faults had led
him to commit them. His errors were detected
and pointed out with demonstrative evidence by
Varignon, Saurin, and some others, who were
among the first to perceive the excellence and
to defend the solidity of the new geometry.
These disputes were of consequence enough to
occupy the attention of the Academy of Sciences
during a great part of the year 1701.
The Abbe Gallois joined with Rolle in his
hostility to the calculus ; and though he added
very little to the force of the attack, he kept the
field after the other had retired from the combat.
Fontenelle, in his Eloge on the Abbe, has given
an elegant turn to the apology he makes for
him. “ His taste for antiquity made him sus¬
picious of the geometry of infinites. He was,
in general, no friend to any thing that was
new, and was always prepared with a kind
of ostracism to put down whatever appeared too
conspicuous for a free state like that of letters.
The geometry of infinites had both these faults,
and particularly the latter.”
After all these disputes were quieted in France,
and the new analysis appeared completely vic¬
torious, it had an attack to sustain in England
from a more formidable quarter. Berkeley, bi¬
shop of Cloyne, wns a man of first-rate talents,
distinguished as a metaphysician, a philosopher,
and a divine. His geometrical knowledge, how¬
ever, which, for an attack on the method of
fluxions, was more essential than all his other
accomplishments, seems to have been little more
than elementary. The motive which induced
him to enter on discussions so remotely connect¬
ed with his usual pursuits, has been variously
represented; but, whatever it was, it gave rise
to the Analyst, in which the author professes to
demonstrate, that the new analysis is inaccurate
in its principles, and that if it ever lead to true
conclusions, it is from an accidental compensa¬
tion of errors that cannot be supposed always to
take place. The argument is ingeniously and
plausibly conducted, and the author sometimes
attempts ridicule with better success than could
be expected from the subject: thus, when he
calls ultimate ratios the ghosts of departed quan¬
tities, it is not easy to conceive a witty saying
more happily fastened on a mere mathematical
abstraction.
The Analyst was answered by Jurin, under
the signature of Philalethes ; and to this Berke¬
ley replied in a tract entitled A Defence of Free-
thinking in Mathematics. Replies were again
made to this; so that the argument assumed the
form of a regular controversy; in which, though
the defenders of the calculus had the advantage,
it must be acknowledged that they did not al¬
ways argue the matter quite fairly, nor exactly
meet the reasoning of their adversary. The true
answer to Berkeley was, that what he conceived
to be an accidental compensation of errors was
not at all accidental, but that the two sets of
quantities that seemed to him neglected in the
reasoning were in all cases necessarily equal,
and an exact balance for one another. The New¬
tonian idea of a fluxion contained in it this truth,
and so it was argued by Jurin and others, but
not in a manner so logical and satisfactory as
might have been expected. Perhaps it is not
too much to assert, that this was not complete¬
ly done till Lagrange’s Theory of Functions ap¬
peared. Thus, if the author of the Analyst has
had the misfortune to enrol his name on the
side of error, he has also had the credit of pi’o-
posing difficulties of which the complete solu¬
tion is only to be derived from the highest im¬
provements of the calculus.
This controversy made some noise in Eng¬
land, but I do not think that it ever drew much
attention on the Continent. The Analyst, I ima¬
gine, notwithstanding its acuteness, never crossed
the Channel. Montucla evidently knows it only
by report, and seems as little acquainted with
the work as with its author, of whom he speaks
very slightly, and supposes he has sufficiently
described him by saying, that he has written
a book against the existence of matter, and
DISSERTATION FOURTH.
651
another in praise of tar-water. But it is less
from the opinions which men support than
from the manner in which they support them,
that their talents are to he estimated. If we
judge by this criterion, we shall pronounce
Berkeley to he a man of genius, whether he be
employed in attacking the infinitesimal ana¬
lysis, in disproving the existence of the ex¬
ternal world, or in celebrating the virtues of
tar-water.1
SECTION II.
MECHANICS, GENERAL PHYSICS, &c.
The discoveries of Galileo, Descartes, and
other mathematicians of the seventeenth cen¬
tury, had made known some of the most ge¬
neral and important laws which regulate the
phenomena of moving bodies. The inertia, or
the tendency of body, when left to itself, to pre¬
serve unchanged its condition either of motion
or of rest; the effect of an impulse communi¬
cated to a body, or of two simultaneous im¬
pulses, had been carefully examined, and had
led to the discovery of the composition of mo¬
tion. The law of equilibrium, not in the lever
alone, but in all the mechanical powers, had
been determined; and the equality of action to
re-action, or of the motion lost to the motion
acquired, had not only been established by rea¬
soning, but confirmed by experiment. The
fuller elucidation and further extension of these
principles were reserved for the period now
treated of.
The development of truth is often so gra¬
dual, that it is impossible to assign the time
when certain principles have been first intro¬
duced into science. Thus, the principle of vir¬
tual velocities, as it is termed, which is now re¬
cognised as regulating the equilibrium of all
machines whatsoever, was perceived to hold in
particular cases, long before its full extent or its
perfect universality was understood. Galileo
made a great step toward the establishment of
this principle when he generalized the property
of the lever, and showed, that an equilibrium
takes place whenever the sums of the opposite
momenta are equal, meaning by momentum the
product of the force into the velocity of the
point at which it is applied. This was carried
farther by Wallis, who appears to have been
the first writer who, in his Mechanica, published
in 1669, founded an entire system of statics on
the principle of Galileo, or the equality of the
opposite momenta. The proposition, however,
was first enunciated in its full generality, and
with perfect precision,2 by John Bernoulli, in
a letter to Varignon, so late as the year 1717.
Varignon inserted this letter at the end of the
second edition of his Projet d’une Nouvelle Me-
intr3h0U| weikele.T reasons Yery plausibly, and with considerable address, he hurts his cause by the comparison so often
, , 0(“l,ced between the mysteries of religion and what he accounts the mysteries of the new geometry. From this it is
iW1 i t0 inifer’ t iat the au,thor.is avenginS the cause of religion on the infidel mathematician to whom his treatise is ad-
lose somewht^oAtfTeT’ht^21 ^ SUSpeCted t0 have all-v other obJect than that at which it is directly aimed, must always
hJ1- <?isI)ute l^re mentioned did not take place till about the year 1734; so that I have here treated of it by anticina-
curinoA-ho J,in'vi h^g to resume the subject of controversies which, though perhaps useful at first for the purpose of se-
mg the foundations of science, are long since set to rest, and never likely to be revived.
senuencpnf HClplef0t' Jelocitie,s be thus enunciated: If a system of bodies be in a state of equilibrium, in con-
ment de^rnt^ ^!°n °f ^ forces whatever on certain points m the system ; then, supposing the equilibrium to be for a mo-
Dlied to .q . S’-Jhe Slmjdl space ni,0yed °J.ev b>' each of these Points wiil express the virtual velocity of the power ap-
tPh’ l ° V;^ lf ea^ f°rce he multiplied into its virtual velocity, the sum of all the products where the velocities are in
T1 ! ec^lon’ WlP he equal to the sum of all those in which they are in the opposite,
well !!l(iIStlllCt^n hef"een actual and virtual velocities was first made by Bernoulli, and is very essential to thinking as
well as to speaking with accuracy on the nature of equilibriums.
652
PRELIMINARY DISSERTATIONS.
canique, which was not published till 1725. The
first edition of the same hook appeared in 1687,
and had the merit of deriving the whole theory
of the equilibrium of the mechanical powers
from the single principle of the composition of
forces. At first sight, there appear in mechanics
two independent principles of equilibrium; that
of the lever, or of equal and opposite momenta,
and that of the composition of forces. To show
that these coincide, and that the one may he
deduced from the other, is, therefore, doing a
service to science; and this the ingenious author
just named accomplished by help of a property
of the parallelogram, which he seems to have
been the first who demonstrated.
The Principia Mathematica of Newton, pub¬
lished also in 1687, marks a great era in the
history of human knowledge, and had the merit
of effecting an almost entire revolution in me¬
chanics, by giving new powers and a new di¬
rection to its researches. In that work the com¬
position of forces was treated independently of
the composition of motion, and the equilibrium
of the lever was deduced from the former, as
well as in the treatise already mentioned. From
the equality of action and re-action it was also
inferred, that the state of the centre of gravity
of any system of bodies is not changed by the
action of those bodies on one another. This is
a great proposition in the mechanics of the
universe, and is one of the steps by which
that science ascends from the earth to the
heavens; for it proves that the quantity of mo¬
tion existing in nature, when estimated in any
one given direction, continues always of the
same amount.
But the new applications of mechanical rea¬
soning,—the reduction of questions concerning
force and motion to questions of pure geometry,
and the mensuration of mechanical action by
its nascent effects,—are what constitute the great
glory of the Principia^ considered as a treatise
on the theory of motion. A transition was there
made from the consideration of forces acting at
stated intervals, to that of forces acting conti¬
nually,—and from forces constant in quantity
and direction to those that converge to a point,
and vary as any function of the distance from
that point; the proportionality of the areas de¬
scribed about the centre of force, to the times of
their description; the equality of the velocities
generated in descending through the same dis¬
tance by whatever route ; the relation between
the squares of the velocities produced or extin¬
guished ; and the sum of the accelerating or re¬
tarding forces, computed with a reference, not
to the time during which, hut to the distance
over which they have acted. These are a few
of the mechanical and dynamical discoveries con¬
tained in the same immortal work; a fuller ac¬
count of which belongs to the history of physi¬
cal astronomy.
The end of the seventeenth and the beginning
of the eighteenth centuries were rendered illus¬
trious, as we have already seen, by the mathe¬
matical discoveries of two of the greatest men
who have ever enlightened the world. A slight
sketch of the improvements which the theory of
mechanics owes to Newton has been just given;
those which it owes to Leibnitz, though not
equally important, nor equally numerous, are
far too conspicuous to be passed over in silence.
So far as concerns general principles, they are
reduced to three; the argument of the suffi¬
cient reason, the law of continuity, and the
measurement of the force of moving bodies by
the square of their velocities; which last being
a proposition that is true or false according to
the light in which it is viewed, I have supposed
it placed in that which is most favourable.
With regard to the first of these, the prin¬
ciple of the sufficient reason, according to which,
nothing exists in any state without a reason de¬
termining it to be in that state rather than in
any other,—though it be true that this proposi¬
tion was first distinctly and generally announced
by the philosopher just named, yet is it certain
that, long before his time, it had been employed
by others in laying the foundations of science.
Archimedes and Galileo had both made use of
it; and perhaps there never was any attempt to
place the elementary truths of science on a solid
foundation, in which this principle had not been
employed. We have an example of its applica¬
tion in the proof usually given, that a body in
motion cannot change the direction ot its mo¬
tion, abstraction being made from all other bo¬
dies, and from all external action ; tor it is evi-
DISSERTATION FOURTH.
653
dent, that no reason exists to determine the
change of motion to be in one direction more
than another, and we therefore conclude that no
such change can possibly take place. Many
other instances might he produced where the
same principle appears as an axiom of the clear¬
est and most undeniable evidence. Wherever,
indeed, we can pronounce with certainty that
the conditions which determine two different
things, whether magnitudes or events, are in
two cases precisely the same, it cannot he
doubted that these events or magnitudes are in
all respects identical.
However sound this principle may be in it¬
self, the use which Leibnitz sometimes made of
it has tended to bring it into discredit. He ar¬
gued, for example, that of the particles of mat¬
ter no two can possess exactly the same proper¬
ties, or can perfectly resemble one another,
otherwise the Supreme Being could have no
reason for employing one of them in a particu¬
lar position more than another, so that both
must necessarily be rejected. To argue thus, is
to suppose that we completely understand the
manner in which motives act on the mind of
the Divinity;1 a postulate that seems but ill
suited to the limited sphere of the human under¬
standing. But, if Leibnitz has misapplied his
own principle, and extended its authority too
far, this affords no ground for rejecting it when
we are studying the ordinary course of nature,
and arguing about the subjects of experiment
and observation. In fact, therefore, the sciences
which aspire to place their foundation on the so¬
lid basis of necessary truth, are much indebted
to Leibnitz for the introduction of this principle
into philosophy.
Another principle of great use in investigat¬
ing the laws of motion, and of change in gene¬
ral, was brought into view by the same author,
—the law of continuity^—according to which, no¬
thing passes from one state to another without
passing through all the intermediate states.
Leibnitz considers himself as the first who made
known this law; but it is fair to remark, that,
in as much as motion is concerned, it was dis¬
tinctly laid down by Galileo,2 and ascribed by
him to Plato. But, though Leibnitz was not
the first to discover the law of continuity, he
was the first who regarded it as a principle in
philosophy, and used it for trying the consistency
of theories, or of supposed laws of nature, and
the agreement of their parts with one another.
It was in this way that he detected the error of
Descartes’s conclusions concerning the collision
of bodies, showing, that though one case of col¬
lision must necessarily graduate into another,
the conclusions of that philosopher did by no
means pass from one to another by such gradual
transition. Indeed, for the purpose of such de¬
tections, the knowledge of this law is extremely
useful; and I believe few have been much oc¬
cupied in the investigations either of the pure or
mixed mathematics, who have not often been
glad to try their own conclusions by the test
which it furnishes.
Leibnitz considered this principle as known a
priori; because if any saltus were to take place,
that is, if any change were to happen without
the intervention of time, the thing changed
must be in two different conditions at the same
individual instant, which is obviously impossible.
Whether this reasoning be quite satisfactory or
not, the conformity of the law to the facts gene¬
rally observed, cannot but entitle it to great au¬
thority in judging of the explanations and theo¬
ries of natural phenomena.
It was the usual error, however, of Leibnitz
and his followers, to push the metaphysical prin¬
ciples of science into extreme cases, where they
lead to conclusions to which it was hardly pos¬
sible to assent. The Academy of Sciences at
Paris having proposed as a prize question the
Investigation of the Laws of the Communication
of Motion,3 John Bernoulli presented an Essay
on the subject, very ingenious and profound; in
which, however, he denied the existence of hard
bodies, because, in the collision of such bodies,
1 The argument of Leibnitz seems evidently inconclusive. For, though there were two similar and equal atoms, yet as
they could not co-exist in the same space, they would not, so far as position is concerned, bear the same relation to the par¬
ticles that surrounded them: there might exist, therefore, considering them as part of the materials to be employed in the
construction of the universe, very good reasons for assigning different situations to each.
* Opere di Galileo, tom. III. p. 150, and tom. II. p. 32. edit. Padova, 1744.
3 In 1724.
654
PRELIMINARY DISSERTATIONS.
a finite change of motion must take place in an
instant; an event which, on the principle just ex¬
plained, he maintained to he impossible. Though
the Essay was admired, this conclusion was ob¬
jected to; and D’Alembert, in his Eloge on the
author, remarks, that, even in the collision of
elastic bodies, it is difficult to conceive how,
among the parts which first come into contact,
a sudden change, or a change per soltum, can be
avoided. Indeed it can only be avoided by sup¬
posing that there is no real contact, and that
bodies begin to act upon one another when their
surfaces, or what seems to be their surfaces, are
yet at a distance.
Maclaurin and some others are disposed, on
account of the argument of Bernoulli, to reject
the law of continuity altogether. This, however,
I cannot help thinking, is to deprive ourselves
of an auxiliary that, under certain restrictions,
may be very useful in our researches, and is
often so, even to those who profess to reject its
assistance. It is admitted that the law of con¬
tinuity generally leads right; and if it sometimes
lead wrong, the true business of philosophy is to
define when it may be trusted to as a safe guide,
and what, on the other hand, are the circum¬
stances which render its indications uncertain.
The discourse of Bernoulli, just referred to,
brought another new conclusion into the field,
and began a controversy among the mathemati¬
cians of Europe, which lasted for many years.
It was a new thing to see geometers contending
about the truths of their own science, and op¬
posing one demonstration to another. The
spectacle must have given pain to the true phi¬
losopher, but may have afforded consolation to
many who had looked with envy on the certain¬
ty and quiet prevailing in a region from which
they found themselves excluded.
Descartes had estimated the force of a moving
body by the quantity of its motion, or by the
product of its velocity into its mass. The ma¬
thematicians and philosophers who followed him
did the same, and the product of these quantities
was the measure of force universally adopted.
No one indeed had ever thought of questioning
the conformity of this measure to the phenomena
of nature, when, in 1686, Leibnitz announced in
the Leipsic Journal the demonstration of a great
error committed by Descartes and others, in esti¬
mating the force of moving bodies. In this paper
the author endeavoured to show, that the force
of a moving body is not proportional to its velo¬
city simply, but to the square of its velocity; and
he supported this new doctrine by very plausible
reasoning. A body, he says, projected upward
against gravity, with a double velocity, ascends
to four times the height; with the triple veloci¬
ty, to nine times the height; and so on, the
height ascended to being always as the square of
the velocity. But the height ascended to is the
effect, and is the natural measure of the force;
therefore the force of a moving body is as the
square of its velocity. Such was the first rea¬
soning of Leibnitz on this subject,—simple, and
apparently conclusive; nor should it be forgotten
that, during the long period to which the dis¬
pute was lengthened out, and notwithstanding
the various shapes which it assumed, the reason¬
ings on his side were nothing more than this ori¬
ginal argument, changed in its form, or render¬
ed more complex by the combination of new
circumstances, so as to be more bewildering to
the imagination, and more difficult either to ap¬
prehend or to refute.1
John Bernoulli was at first of a different
opinion from his friend and master, but came at
length to adopt the same; which, however, ap¬
pears to have gone no farther till the discourse
was submitted to the Academy of Sciences, as
has been already mentioned. The mathematical
world could not look with indifference on a
question which seemed to affect the vitals of
mechanical science, and soon separated into two
parties, in the arrangement of which, however,
the effects of national predilection might easily
be discovered. Germany, Holland, and Italy,
declared for the vis viva ; England stood firm
for the old doctrine; and France was divided
between the two opinions. No controversy,
1 To mere pressure Leibnitz gave the name of vis mortva. and to the force of moving bodies the name of vis viva. The
former he admitted to be proportional to the simple power of the virtual velocity, and the second he held to be proportion*
al to the square of the actual veloci ty.
DISSERTATION FOURTH.
655
perhaps, was ever carried on by more illustrious
disputants: Maclaurin, Stirling, Desaguliers,
Jurin, Clarke, Mairan, were engaged on the
one side; on the opposite were Bernoulli, Her¬
mann, Poleni, S’Gravesande, Muschenbroeck;
and it was not till long after the period to which
this part of the Dissertation is confined, that the
debate could be said to be brought to a conclu¬
sion. That I may not, however, be obliged to
break off a subject of which the parts are close¬
ly connected together, I shall take the liberty of
transgressing the limits which the consideration
of time would prescribe, and of now stating, as
far as my plan admits of it, all that respects this
celebrated controversy.
A singular circumstance may be remarked in
the whole ol the dispute. The two parties who
adopted such different measures of force, when
any mechanical problem was proposed concern¬
ing the action of bodies, whether at rest or in
motion, resolved it in the same manner, and
arrived exactly at the same conclusions. It was
therefore evident, that, however much their
language and words were opposed, their ideas
or opinions exactly agreed. In reality, the two
parties were not at issue on the question; their
positions, though seemingly opposite, were not
contrary to one another; and after debating for
nearly thirty years, they found out this to be the
truth. That the first men in the scientific world
should have disputed so long with one another,
without discovering that their opposition was
onlyin words,—and that this should havehappen-
ed, not in any of the obscure and tortuous tracks
through which the human mind must grope its
way in anxiety and doubt, but in one of the
clearest and straightest roads, where it used to
be guided by the light of demonstration,—is one
of the most singular facts in the history of hu¬
man knowledge.
The degree of acrimony and illiberality which
were sometimes mixed in this controversy was
not very creditable to the disputants, and proved
how much more men take an interest in opinions
as being their own, than as being simply in
themselves either true or false. The dispute, as
conducted by S’Gravesande and Clarke, took
this turn, especially on the part of the latter,
who, in the schools of theology having sharp¬
ened both his temper and his wit, accompanied
his reasonings with an insolence and irritability
peculiarly ill suited to a discussion about matter
and motion. His paper on this subject, in the
Philosophical Transactions)* contains many just
and acute remarks, accompanied with the most
unfair representation of the argument of his an¬
tagonists, as if the doctrine of the vis viva were
a matter of as palpable absurdity as the denial
of one of the axioms of geometry.2 Now, the
tiuth is, that the argument in favour of living
forces is not at all liable to this reproach. One
of the effects produced by a moving body is pro¬
portional to the square of the velocity, while
another is proportional to the velocity simply;
and, according to which of these ways the force
itself is to be measured, may involve the pro¬
priety or impropriety of mathematical language,
but cannot be charged with absurdity or contra¬
diction. Absurdity, indeed, was a reproach that
neither side had any right to cast on the other.
A Dissertation of Mairan, on the Force of
moving Bodies, in the Memoirs of the Academy of
Sciences for 1728, is one of those in which the
common measure of force is most ably support¬
ed. Nevertheless, for a long time after this,
the opinions on that subject in France continued
still to be divided. In the list of the disputants
we should hardly expect to find a lady included,
if we did not know that the name of Madame
du Chastelet, along with those of Hypatia and
Agnesi, was honourably enrolled in the annals
of mathematical learning. Her writings on this
• tV01*„X?XV' 6728) p. 381 : Hutton’s Abridgement, vol. VII. p. 219.
toniinMll ?;rSunients for the vis viva, this learned metaphysician saw nothing but a conspiracy formed against the New-
had of An extraordinlaiy instance,” says he, “ of the maintenance of the mist palpable abSty we have
nf .f? years ln vei,y eminent mathematicians, Leibnitz, Bernoulli, Hermann, S’Gravesande, who in order to raise a dust
verts^alTscience^and .^jewtonian philosophy, some years back insisted with great eagerness on’a principle which sub-
essential naturf’ f o easil>r be made aPl-'ear, even to an ordinary capacity, to be contrary to the necessary and
time makinlSpm^K SerVe aS a pi'?°f of the spirit which prevailed among the philosophers of that
those of their ndvpr - C‘* 6 V1ieWS t0 0116 an°ther5 and distorting so entirely both their own reasoning and
tnose ot then adversaries. The spirit awakened by the discovery effluxions had not yet subsided.
656
preliminary dissertations.
subject are full of ingenuity, though, from the
fluctuation of her opinions,1 * it seems as if she
had not yet entirely exchanged the caprice of
fashion for the austerity of science. About the
same time Voltaire engaged in the argument,
and in a Memoir,* presented to the Academy
of Sciences in 1741, contended that the dispute
was entirely about words. His reasoning is, on
the whole, sound; and the suffrage of one who
united the character of a wit, a poet, and a phi¬
losopher, must be of great importance in a coun¬
try where the despotism of fashion extends even
to philosophical opinion.
The controversy was now drawing to a con¬
clusion,3 and in effect may be said to have been
terminated by the publication of D Alembert s
Dynamique in 1743. I am not certain, how¬
ever, that all the disputants acquiesced in this
decision, at least till some years later. Hr Reid,
in an Essay on Quantity, in the Philosophical
Transactions for 1748, has treated of this con¬
troversy, and remarked, that it had been dropt
rather than concluded. In this I confess I differ
from the learned author. The controversy seem¬
ed fairly ended, the arguments exhausted, and
the conclusion established, that the propositions
maintained by both sides were true, and were
not opposed to one another. Though the ma¬
thematical sciences cannot boast of never hav¬
ing had any debates, they can say that those
that have arisen have always been brought to a
satisfactory termination.
The observations with which I am to con¬
clude the present sketch, are not precisely the
same with those of the French philosopher,
though they rest nearly on the same founda¬
tion.
As the effects of moving bodies, or the changes
they produce, may vary considerably with acci¬
dental circumstances, we must, in order to mea¬
sure their force, have recourse to effects which
are uniform, and not under the influence of va¬
riable causes. First, we may measure the force
of one moving body by its effect upon another
moving body; and here there is no room for
dispute, nor any doubt that the forces of such
bodies are as the quantities of matter multiplied
into the simple power of the velocities, because
the forces of bodies in which these products are
equal, are well known, if opposed, to destroy
one another. Thus one effect of moving bodies
affords a measure of their force, which does not
vary as the square^ but as the simple power of
the velocity.
There is also another condition of moving bo¬
dies which may be expected to afford a simple
and general measure of their force. When a
moving body is opposed by pressure, by a vis
mortua, or a resistance like that of gravity, the
quantity of such resistance required to extinguish
the motion, and reduce the hody to rest, must
serve to measure the force of that body. It is
a force which, by repeated impulses, has anni¬
hilated another; and these impulses, when pro¬
perly collected into one sum, must evidently be
equal to the force which they have extinguished.
It happens, however, that there are two ways of
computing the amount of these retarding foi’ces,
which lead to different results, hoth of them
just, and neither of them to be assumed to the
exclusion of the other.
Suppose the body, the force of which is to be
measured, to be projected perpendicularly up¬
ward with any velocity; then, if we would com¬
pute the quantity of the force of gravity which
is employed in reducing it to rest, we may eithei
inquire into the retardation which that force
produces during a given time, or while the body
is moving over a given space. In other words,
we may either inquire how long the motion will
■ Madame du Chastelet, in a Dissertation on Fire, published in 1740, took the side of Mairan, and bestowed great praise
on his discourse on the Force of moving Bodies. Having, however, afterwards become a convert to e p n osop .
nitz, she espoused the cause of the vis viva, and wrote against Mairan. At this time too she drew up a comp 1
Leibnitian philosophy for the use of her son, which displays ingenuity and acuteness, and is certainly sue i a j
verv few mothers have ever been in a condition to make to their children. Soon afterwards the same la‘*>b aV1f?,.,„pn
a Newtonian, returned to her former opinion about the force of moving bodies, and in the end, gave to hei conn i}
excellent translation of the Principia of Newton, with a commentary on a part of it, far superior to any ot ler ia y
1 2 Doutcs sur la MImre des Forces Matrices: CEuvres de Voltaire, tom. XXXIX. p. 91. 8vo edit. 1785. . .
* Two very valuable papers that appeared at this late period of the dispute are found in the Philosophtca »
one bv Desaguliers, in 1733, full of excellent remarks and valuable experiments ; another by Junn, in 1745, con i g
very full state of the whole controversy.
DISSERTATION FOURTH.
657
continue, or how far it will carry the body be¬
fore it be entirely exhausted. If the length of
the time that the uniform resistance must act
before it reduce the body to rest be taken for
the effect, and consequently for the measure of
the force of the body, that force must be pro¬
portional to the velocity, for to this the time is
confessedly proportional. If, on the other hand,
the length of the line which the moving body
describes, while subjected to this uniform re¬
sistance, be taken for the effect and the measure
of the force, the force must be as the square of
the velocity, because to that quantity the line in
question is known to be proportional. Here,
therefore, are two results, or two values of the
same thing, the force of a moving body, which
are quite different from one another; an incon¬
sistency which evidently arises from this, that
the thing denoted by the term force is too vague
and indefinite to be capable of measurement,
unless some further condition be annexed. This
condition is no other than a specification of the
work to be performed, or of the effect to be pro¬
duced by the action of the moving body. Thus,
when to the question concerning the force of
the moving body you add that it is to be em¬
ployed in putting in motion another body which
is itself free to move, no doubt remains that the
force is as the velocity multiplied into the quan¬
tity of matter. So also, if the force of the mov¬
ing body is to be opposed by a resistance like
that of gravity, the length of time that the mo¬
tion may continue is one of its measurable ef¬
fects, and that effect is, like the former, propor¬
tional to the velocity. There is a third effect to be
considered, and one which always occurs in such
an experiment as the last,—the height to which
the moving body will ascend. This limitation
gives to the force a definite character, and it is
now measured by the square of the velocity.
In fact, therefore, it is not a precise question to
ask, What is the measure of the force of a
moving body ? You must, in addition, say, How
is the moving body to be employed, or in which
of its different capacities is it that you would
measure its effect ? In this state of the question
there is no ambiguity, nor any answer to be
given but one. Hence it was that the mathe¬
maticians and philosophers who differed so much
DISS. IV., PART II.
about the general question of the force of moving
bodies, never differed about the particular ap¬
plications of that force. It was because the
condition necessary for limiting the vagueness
and ambiguity of the data, in all such cases,
was fully supplied.
In the argument, therefore, so strenuously
maintained on the force of moving bodies, both
sides were partly in the right and both partly in
the wrong. Each produced a measure of force
which was just in certain circumstances, and
thus far had truth on his side: but each argued
that his was the only true measure, so that all
others ought to be rejected; and here each of
them was in error. Hence, also, it is not an
accurate account of the controversy to say that
it was about words merely: the disputants did
indeed misunderstand one another; but their
error lay in ascribing generality to propositions
that were true only in particular cases, to which
indeed the ambiguity and vagueness of the word
force materially contributed. It does not ap¬
pear, however, that any good would now accrue
from changing the language of dynamics. If,
as has been already said, to the question, How
are we to measure the force of a moving body ?
be added the nature of the effect which is to be
produced, all ambiguity will be avoided.
It is, I think, only further necessary to ob¬
serve, that when the resistance opposed to the
moving body is not uniform but variable, ac¬
cording to any law, it is not simply either the
time or the space which is proportional to the
velocity or to the square of the velocity, but
functions of those quantities. These functions
are obtained from the integration of certain
fluxionary expressions, in which the measures
above described are applied, the resistance being
regarded as uniform for an infinitely small por¬
tion of the time or of the space.
Many years after the period I am now treat¬
ing of, the controversy about the vis viva seemed
to revive in England, on the occasion of an Es¬
say on Mechanical Force, by the late Mr Smea-
ton, an able engineer, who, to great practical
skill, and much experience, added no inconsid¬
erable knowledge of the Mathematics.
The reality of the vis viva, then, under cer¬
tain conditions, is to be considered as a matter
4 o
658
PRELIMINARY DISSERTATIONS.
completely established. Another inquiry con¬
cerning the nature of this force, which also gave
rise to considerable debate, was, whether, in the
communication of motion, and in the various
changes through which moving bodies pass, the
quantity of the vis viva remains always the
same. It had been observed, in the collision
of elastic bodies, that the vis viva, or the sum
made up by multiplying each body into the
square of its velocity, and adding the products
together, was the same after collision that it was
before it; and it was concluded with some pre¬
cipitation, by those who espoused the Leibnitian
theory, that a similar result always took place
in the real phenomena of nature. Other in¬
stances were cited; and it was observed, that a
particular view of this principle which present¬
ed itself to Huygens, had enabled him to find
the centre of oscillation of a compound pendu¬
lum, at a time when the state of mechanical
science was scarcely prepared for so difficult an
investigation. The proposition, however, is true
only when all the changes are gradual, and ri¬
gorously subjected to the law of continuity.
Thus, in the collision of bodies imperfectly
elastic, (a case which continually occurs in na¬
ture) the force which, during the recoil, acce¬
lerates the separation of the bodies, does not
restore to them the whole velocity they had lost;
and the vis viva, after the collision, is always
less than it was before it. The cases in which
the whole amount of the vis viva is rigorously
preserved, may always he brought under the
thirty-ninth proposition of the first hook of the
Principia, where the principle of this theory is
placed on its true foundation.
So far as general principles are concerned,
the preceding are the chief mechanical improve¬
ments which belong to the period so honourably
distinguished by the names of Newton and Leib¬
nitz. The application of these principles to the
solution of particular problems would afford
materials for more ample discussion than suits
the nature of an historical outline. Such pro¬
blems as that of finding the centre of oscilla¬
tion,—the nature of the catenarian curve,—the
determination of the line of swiftest descent,—
the retardation produced to motion in a medium
that resists according to the square of the velo¬
city, or indeed according to any function of
it,—the determination of the elastic curve, or
that into which an elastic spring forms itself
when a force is applied to bend it;—all these
were problems of the greatest interest, and were
now resolved for the first time; the science of
mechanics being sufficient, by means of the com¬
position of forces, to find out the fluxionary or
differential equations which expressed the nature
of the gradual changes which in all these cases
were produced, and the calculus being now suffi¬
ciently powerful to infer the properties of the
finite from those of the infinitesimal quantities.
The doctrine of Hydrostatics was cultivated
in England by Cotes. The properties of the
atmosphere, or of elastic fluids, were also ex¬
perimentally investigated; and the barometer,
after the ingenuity of Pascal had proved that the
mercury stood lower the higher up into the atmo¬
sphere the instrument was carried, was at length
brought to he a measure of the height of moun¬
tains. Mariotte appears to have been the first
who proposed this use of it, and who discovered
that, while the height from the ground increases
in arithmetical, the density of the atmosphere
and the column of mercury in the barometer
decrease in geometrical progression. Halley,
who seems also to have come of himself to the
same conclusion, proved its truth by strict geo¬
metrical reasoning, and showed that logarithms
are easily applicable on this principle to the pro¬
blem of finding the height of mountains. This
was in the year 1685. Newton two years after¬
wards gave a demonstration of the same, extend¬
ed to the case when gravity is not constant, hut
varies as any power of the distance from a given
centre.
To the assiduous observations and the inde¬
fatigable activity of Halley, the natural history
of the atmosphere, of the ocean, and of magne¬
tism, are all under the greatest obligations. For
the purpose of inquiring into these objects, this
ardent and philosophical observer relinquished
the quiet of academical retirement, and, having
gone to St Helena, by a residence of a year in
that island, not only made an addition to the
catalogue of the stars, of 360 from the southern
hemisphere, hut returned with great acquisitions
both of nautical and meteorological knowledge.
DISSERTATION FOURTH.
659
His observations on evaporation were the foun¬
dation of two valuable papers on the origin of
fountains; in which, for the first time, the suffi¬
ciency of the vapour taken up into the atmo¬
sphere, to maintain the perennial flow of springs
and rivers, was established by undeniable evi¬
dence. The difficulty which men found in con¬
ceiving how a precarious and accidental supply
like that of the rains can sufficiently provide
for a great and regular expenditure like that of
the rivers, had given rise to those various opin¬
ions concerning the origin of fountains, which
had hitherto divided the scientific world. A
long residence on the summit of an insulated
rock, in the midst of a vast ocean, visited twice
every year by the vertical sun, would have af¬
forded to an observer less quick-sighted than
Halley, an opportunity of seeing the work of
evaporation carried on with such rapidity and
copiousness as to be a subject of exact measure¬
ment. From this extreme case, he could infer
the medium quantity, at least by approximation ;
and he proved that, in the Mediterranean, the
humidity daily raised up by evaporation is three
times as great as that which is discharged by all
the rivers that flow into it. The origin of foun¬
tains was no longer questioned; and of the mul¬
titude of opinions on that subject, which had
hitherto perplexed philosophers, all but one en¬
tirely disappeared.1
Beside the voyage to St Helena, Halley made
two others; the British government having been
enlightened and liberal enough to despise pro¬
fessional etiquette, where the interests of science
were at stake, and to intrust to a Doctor of
Laws the command of a ship of war, in which he
traversed the Atlantic and Pacific Oceans in
various directions, as far as the 53d degree of
south latitude, and returned with a collection
of facts and observations for the improvement
of geography, meteorology, and navigation, far
beyond that which any individual traveller or
voyager had hitherto brought together.
The variation of the compass was long before
this time known to exist, but its laws had never yet
been ascertained. These Halley now determined
from his own observations, combined with those
of former navigators, in so far as to trace, on a
nautical chart, the lines of the same variation
over a great part both of the Atlantic and Pa¬
cific Oceans, affording to the navigator the ready
means of correcting the errors which the devia¬
tion of the needle from the true meridian was
calculated to produce. In his different traverses
he had four times intersected the line of no vari¬
ation, which seemed to divide the earth into two
parts, the variations on the east side being to¬
wards the west, and on the west side towards
the east. These lines being found to change
their position in the course of time, the place
assigned to the magnetical poles could not be
permanent. Any theory, therefore, which could
afford an explanation of their changes, must ne¬
cessarily be complex and difficult to be esta¬
blished. The attempt of Halley to give such an
explanation, though extremely ingenious, was
liable to great objections; and while it has
shared the fate of most of the theories which
have been laid down before the phenomena had
been sufficiently explored, the general facts
which he established have led to most of the
improvements and discoveries which have since
been made respecting the polarity of the needle.
Besides the conclusion just mentioned, Di
Halley derived from his observations a very
complete history of the winds which blow in
the tropical regions, viz. the trade-wind and
the monsoons, together with many interesting
facts concerning the phenomena of the tides.
The chart which contained an epitome of all
these facts was published in 1701.
The above are only a part of the obligations
which the sciences are under to the observations
and reasonings of this ingenious and indefati¬
gable inquirer. Halley was indeed one of the
ablest and most accomplished men of his age.
A scholar well versed in the learned languages,
and a geometer profoundly skilled in the ancient
analysis, he restored to their original elegance
some of the precious fragments of that analysis,
which time happily had not entirely defaced.
He was well acquainted also with the algebrai¬
cal and fluxionary calculus, and was both in
theory and practice a profound and laborious
1 Philosophical Transactions, 1G87, vol. XVI. p. 3GG.
660
PRELIMINARY DISSERTATIONS.
astronomer. Finally, he was the friend of New¬
ton, and often stimulated, with good effect, the
tardy purposes of that great philosopher. Few
men, therefore, of any period, have more claims
than Halley on the gratitude of succeeding ages.
The invention of the thermometer has been
already noticed; and the improvements made on
that instrument about this period laid the foun¬
dation of many future discoveries. The dis¬
covery of two fixed temperatures, each marked
by the same expansion of the mercury in the
thermometer, and the same condition of the
fluid in which it is immersed, was made about
this time. The differences of temperature were
thus subjected to exact measurement; the phe¬
nomena of heat became, of course, known with
more certainty and precision; and that sub¬
stance or virtue, to which nothing is impe¬
netrable, and which finds its way through the
rarest and the densest bodies apparently with
the same facility,—which determines so many
of our sensations, and of which the distribution
so materially influences all the phenomena of
animal and vegetable life,—came now to be
known, not indeed in its essence, but as to all
the characters in which we are practically or
experimentally concerned. The treatise on Fire,
in Boerhaave’s Chemistry, is a great advance be¬
yond any thing on that subject hitherto known,
and touches, notwithstanding many errors and
imperfections, on most of the great truths which
time, experience, and ingenuity, have since
brought into view.
It was in this period also that electricity may
be said first to have taken a scientific form. The
power of amber to attract small bodies after it
has been rubbed, is said to have been known to
Thales, and is certainly made mention of by
Theophrastus. The observations of Gilbert, a
physician of Colchester, in the end of the six¬
teenth century, though at the distance of two
thousand years, made the first addition to the
transient and superficial remarks of the Greek
naturalist, and afford a pretty full enumeration
of the bodies which can be rendered electrical
by friction. The Academia del Cimento, Boyle,
and Otto Guericke, followed in the same course;
and the latter is the first who mentions the
crackling noise and faint light which electricity
sometimes produced. These, however, were
hardly perceived, and it was by Dr Wall, as
described in the Philosophical Transactions, that
they were first distinctly observed.1 By a sin¬
gularly fortunate anticipation, he remarks of
the light and crackling, that they seemed in
some degree to represent thunder and light¬
ning.
After the experiments of Hauksbee in 1709,
by which the knowledge of this mysterious sub¬
stance was considerably advanced, Wheeler and
Gray, who had discovered that one body could
communicate electricity to another without rub¬
bing, being willing to try to what distance the
electrical virtue might be thus conveyed, em¬
ployed, for the purpose of forming the commu¬
nication, a hempen rope, which they extended
to a considerable length, supporting it from the
sides by threads, which, in order to prevent the
dissipation of the electricity, they thought it
proper to make as slender as possible. They
employed silk threads with that Hew, and found
the experiment to succeed. Thinking that it
would succeed still better if the supports were
made still more slender, they tried very fine
metallic wire, and were surprised to find that
the hempen rope, thus supported, conveyed no
electricity at all. It was therefore as being silk,
and not as being small, that the threads had
served to retain the electricity. This accident
led to the great distinction of substances con¬
ducting and not conducting electricity. An
extensive field of inquiry was thus opened, a
fortunate accident having supplied an instantia
crucis, and enabled these experimenters to dis¬
tinguish between what was essential and what
was casual in the operation they had performed.
The history of electricity, especially in its early
stages, abounds with facts of this kind; and no
man who would study the nature of inductive
science, and the rules for the interpretation of
nature, can employ himself better than in tra¬
cing the progress of these discoveries. He will
1 Wall’s paper is in the Transactions for 1708, vol. XXVI. No. 314. p. 09. Hauksbee on Electrical Light, in the same
volume. See Abridgement, vol. V. p. 408, 411.
DISSERTATION FOURTH.
661
find abundant reason to admire tbe ingenuity tunely to the assistance of both. The experi-
as well as the industry of the inquirers, but he ments of Wheeler and Gray are described in
will often find accident come in very oppor- the Transactions for 1729.
SECTION III.
OPTICS.
The invention of the telescope and the mi¬
croscope, the discoveries made concerning the
properties of light and the laws of vision, added
to the facility of applying mathematical reason¬
ing as an instrument of investigation, had long
given a peculiar interest to optical researches.
The experiments and inquiries of Newton on
that subject began in 1666, and soon made a
vast addition both to the extent and importance
of the science. He was at that time little more
than twenty-three years old; he had already
made some of the greatest and most original
discoveries in the pure mathematics; and the
same young man, whom we have been admiring
as the most profound and inventive of geome¬
ters, is to appear, almost at the same moment,
as the most patient, faithful, and sagacious in¬
terpreter of nature. These characters, though
certainly not opposed to one another, are not
often combined; but to be combined in so high
a degree, and in such early life, was hitherto
without example.
In hopes of improving the telescope, by giving
to the glasses a figure different from the spheri¬
cal, he had begun to make experiments, and had
procured a glass prism, in order, as he tells us,
to try with it the celebrated phenomena of colours.1
These trials led to the discovery of the different
refrangibility of the rays of light, and are now
too well known to stand in need of a particular
description.
Having admitted a beam of light into a dark
chamber, through a hole in the window-shutter,
and made it fall on a glass prism, so placed as
to cast it on the opposite wall, he was delighted
to observe the brilliant colouring of the sun’s
image, and not less surprised to observe its fi¬
gure, which, instead of being circular, as he ex¬
pected, was oblong in the direction perpendicu¬
lar to the edges of the prism, so as to have the
shape of a parallelogram, rounded at the two
ends, and nearly five times as long as it was
broad.
When he reflected on these appearances, he
saw nothing that could explain the elongation of
the image, but the supposition that some of the
rays of light, in passing through the prism, were
more refracted than others; so that rays which
were parallel when they fell on the prism, di¬
verged from one another after refraction, the
rays that differed in refrangibility differing also
in colour. The spectrum^ or solar image, would
thus consist of a series of circular images, partly
covering one another, and partly projecting one
beyond another, from the red or least refrangible
rays, in succession, to the orange, yellow, green,
blue, indigo, and violet, the most refrangible
of all.
It was not, however, till he tried every other
hypothesis which suggested itself to his mind by
the test of experiment, and proved its fallacy,
that he adopted this as a true interpretation of
the phenomena. Even after these rejections,
his explanation had still to abide the sentence
of an experimentum crucis.
Having admitted the light and applied a prism
1 Philosophical Transactions, vol. VI. (1672) p. 3075: also Hutton’s Abridgement, vol. I. p. 678. The account of the ex¬
periments is in a letter to Oldenburg, dated February 1672 : it is the first of Newton’s works that was published. It is
plain, from what is said above, that the phenomena of the prismatic spectrum were not unknown at that time, however
little they were understood, and however imperfectly observed.
662
PRELIMINARY DISSERTATIONS.
as before, be received the coloured spectrum on
a board at the distance of about twelve feet fiom
the first, and also pierced with a small bole.
The coloured light which passed through this
second hole was made to fall on a prism, and
afterwards received on the opposite wall. It
was then found that the rays which had been
most refracted, or most bent from their couise
by the first prism, were most refracted also by
the second, though no new colours were pro¬
duced. “ So,” says he, “ the true cause of the
length of the image was detected to he no other
than that light consists of rays differently re¬
frangible, which, without any respect to a dif¬
ference in their incidence, were, according to
their degrees of refrangibility, transmitted to¬
wards divers parts of the wall.” 1
It was also observed, that when the rays
which fell on the second prism were all of the
same colour, the image formed by refraction
was truly circular, and of the same colour with
the incident light. This is one of the most con¬
clusive and satisfactory of all the experiments*
When the sun’s light is thus admitted, first
through one aperture, and then through another
at some distance from the first, and is afterwards
made to fall on a prism, as the rays come only
from a part of the sun’s disk, the spectrum has
nearly the same length as before, hut the breadth
is greatly diminished; in consequence of which,
the light at each point is purer, it is free from
penumbra, and the confines of the different co¬
lours can be more accurately traced. It was in
this way that Newton measured the extent of
each colour; and taking the mean of a great
number of measures, he assigned the following
proportions, dividing the whole length of the
spectrum, exclusive of its rounded terminations,
into 360 equal parts: of these the
Red occupied - - 45
Orange ^ - 27
Yellow - - - 48
Green - - 60
Blue - - - 60
Indigo - - 40
Violet - - - 80
Between the divisions of the spectrum, thus
made by the different colours, and the divisions
of the monochord by the notes of music, Newton
conceived that there was an analogy, and indeed
an identity of ratios; hut experience has since
shown that this analogy was accidental, as the
spaces occupied by the different colours do not
divide the spectrum in the same ratio, when
prisms of different kinds of glass are employed.
Such were the experiments by which Newton
first “ untwisted all the shining robe of day,”
and made known the texture of the magic gar¬
ment which nature has so kindly spread over
the surface of the visible world. From them it
followed, that colours are not qualities which
light derives from refraction or reflection, hut
are original and connate properties connected
with the different degrees of refrangihility that
belong to the different rays. The same colour
is always joined to the same degree of refrangi¬
bility ; and conversely, the same degree of re¬
frangibility to the same colour.
Though the seven already enumerated are
primary and simple colours, any of them may
also be produced by a mixture of others. A
mixture of yellow and blue, for instance, makes
green; of red and yellow, orange; and, in ge¬
neral, if two colours which are not very far
asunder in the natural series be mixed together,
they compound the colour that is in the middle
between them.
But the most surprising composition of all,
Newton observes, is that of whiteness; which
is not produced by one sort of rays, but by the
mixture of all the colours in a certain propor¬
tion, namely, in that proportion which they
have in the solar spectrum. This fact may be
said to be made out both by analysis and com¬
position. The white light of the sun can be se¬
parated, as we have just seen, into the seven
simple colours; and if these colours be united
again, they form white. Should any of them
have been wanting, or not in its due proportion,
the white produced is defective.
It appeared, too, that natural bodies, of what¬
ever colour, if viewed by simple and homogene¬
ous light, are seen of the colour of that light, and
of no other. Newton tried this very satisfac-
1 Philosophical Transactions, vol. VI. (1072) No. SO. p. 3075.
DISSERTATION FOURTH.
663
tory experiment on bodies of all colours, and
found it to hold uniformly; the light was never
changed by the colour of the body that reflect¬
ed it.
Newton, thus furnished with so many new
and accurate notions concerning the nature and
production of colour, proceeded to apply them
to the explanation of phenomena. The subject
which naturally offered itself the first to this
analysis was the rainbow, which, by the grandeur
and simplicity of its figure, added to the brilli¬
ancy of its colours, in every age has equally at¬
tracted the attention of the peasant and of the
philosopher. That two refractions and one re¬
flection were at least a part of the machinery
which nature employed in the construction of
this splendid arch, had been known from the
time of Antonio de Dominis; and the manner
in which the arched figure is produced had been
shown by Descartes; so that it only remained
to explain the nature of the colour and its dis¬
tribution. As the colours were the same with
those exhibited by the prism, and succeeded in
the same order, it could hardly be doubted that
the cause was the same. Newton showed the
truth of his principles by calculating the extent
of the arch, the breadth of the coloured bow, the
position of the secondary bow, its distance from
the primary, and by explaining the inversion of
the colours.1 There is not, perhaps, in science
any happier application of theory, or any in
which the mind rests with fuller confidence.
Other meteoric appearances seemed to be ca¬
pable of similar explanations, but the phenomena
being nowhere so regular or so readily subject¬
ed to measurement as those of the rainbow, the
theory cannot be brought to so severe a test, nor
the evidence rendered so satisfactory.
But a more difficult task remained,—to ex¬
plain the permanent colour of natural bodies.
Here, however, as it cannot be doubted that all
colour comes from the rays of light, so we must
conclude that one body is red and another violet,
because the one is disposed to reflect the red or
least refrangible rays, and the other to reflect
the violet or the most refrangible. Every body
manifests its disposition to reflect the light of its
own peculiar colour, by this, that if you cast on
it pure light, first of its own colour, and then of
any other, it will reflect the first much more co¬
piously than the second. If cinnabar, for ex¬
ample, and ultramarine blue be both exposed to
the same red homogeneous light, they will both
appear red, but the cinnabar strongly luminous
and resplendent, and the ultramarine of a faint
obscure red. If the homogeneal light thrown on
them be blue, the converse of the above will
take place.
Transparent bodies, particularly fluids, often
transmit light of one colour and reflect light of
another. Halley told Newton, that, being deep
under the surface of the sea in a diving-bell, in
a clear sunshine day, the upper side of his hand,
on which the sun shone darkly through the
water and through a small glass window in the
diving-bell, appeared of a red colour, like a da¬
mask rose, while the water below, and the under
part of his hand, looked green.2
But, in explaining the permanent colour of
bodies, this difficulty always presents itself:—
Suppose that a body reflects red or green light,
what is it that decomposes the light, and sepa¬
rates the red or the green from the rest ? Re¬
fraction is the only means of decomposing light,
and separating the rays of one degree of refran-
gibility, and of one colour, from those of ano¬
ther. This appears to have been what led New¬
ton to study the colours produced by light pass¬
ing through thin plates of any transparent sub¬
stance. The appearances are very remarkable,
and had already attracted the attention both of
Boyle and of Hooke ; but the facts observed by
them remained insulated in their hands, and un¬
connected with other optical phenomena.
It probably had been often remarked, that
when two transparent bodies, such as glass, of
which the surfaces were convex in a certain de¬
gree, were pressed together, a black spot was
formed at the contact of the two, which was
surrounded with coloured rings, more or less
regular, according to the form of the surfaces.
In order to analyze a phenomenon that seemed
in itself not a little curious, Newton proposed to
make the experiment with surfaces of a regular
1 Optics, book i. part ii. prop. 9.
a Ibid, book i. part ii. prop. 10.
664
PRELIMINARY DISSERTATIONS.
curvature, such as was capable of being mea¬
sured. He took two object-glasses, one a plano¬
convex for a fourteen feet telescope, the other a
double convex for one of about fifty feet, and
upon this last he laid the other with its plane
side downwards, pressing them gently together.
At their contact in the centre was a pellucid
spot, through which the light passed without
suffering any reflection. Round this spot was a
coloured circle or ring, exhibiting blue, white,
yellow, and red. This was succeeded by a
pellucid or dark ring, then a coloured ring of
violet, blue, green, yellow, and red, all copious
and vivid except the green. The third coloured
ring consisted of purple, blue, green, yellow,
and red. The fourth consisted of green and
red; those that succeeded became gradually
more dilute, and ended in whiteness. It was
possible to count as far as seven.
The colours of these rings were so marked by
peculiarities in shade and vivacity, that Newton
considered them as belonging to different orders;
so that an eye accustomed to examine them, on
any particular colour of a natural object being
pointed out, would be able to determine to what
order in this series it belonged.
Thus we have a system of rings or zones sur¬
rounding a dark central spot, and themselves
alternately dark and coloured, that is, alternate¬
ly transmitting the light and reflecting it. It is
evident that the thickness of the plates of air in¬
terposed between the glasses, at each of those
rings, must be a very material element in the
arrangement of this system. Newton therefore
undertook to compute their thickness. Having
carefully measured the diameters of the first six
coloured rings, at the most lucid part of each,
he found their squares to be as the progression
of odd numbers 1, 3, 5, 7, &c. The squares of
the distances from the centre of the dark spot to
each of these circumferences were, therefore, in
the same ratio, and consequently the thickness
of the plates of air, or the intervals between the
glasses, was as the numbers 1, 3, 5, 7, &c.
When the diameters of the dark or pellucid
rings which separated the coloured rings were
measured, their squares were found to be as the
even numbers 0, 2, 4, 6; and, therefore, the
thickness of the plates through which the light
was wholly transmitted was as the same num¬
bers. A great many repeated measurements
assured the accuracy of these determinations.
As the curvature of the convex glass on Avhich
the flat surface of the plano-convex rested was
known, and as the diameters of the rings were
measured in inches, it was easy to compute the
thickness of the plates of air, which correspond¬
ed to the different rings.
An inch being divided into 178000 parts, the
distance of the lenses for the first series, or for
theluminousrings.wasjJ^, ^5o’&c-
2 4
For the second series 178000’ 178000’ &C'
When the rings were examined by looking
through the lenses in the opposite direction, the
central spot appeared white, and, in other rings,
red was opposite to blue, yellow to violet, and
green to a compound of red and violet; the co¬
lours formed by the transmitted and the reflect¬
ed light being what is now called complement-
ary, or nearly so, of one another; that is, such
as, when mixed, produce white.
When the fluid between the glasses was dif¬
ferent from air, as when it was water, the suc¬
cession of rings was the same; the only differ¬
ence was, that the rings themselves were nar¬
rower.
When experiments on thin plates were made
in such a wTay that the plate was of a denser
body than the surrounding medium, as in the
case of soap-bubbles, the same phenomena were
observed to take place. These phenomena New¬
ton also examined with his accustomed ac¬
curacy, and even bestowed particular care on
having the soap-bubbles as perfect and durable
as their frail structure would admit. In the eye
of philosophy no toy is despicable, and no occu¬
pation frivolous, that can assist in the discovery
of truth.
To the different degrees of tenuity, then, in
transparent substances, there seemed to be at¬
tached the powers of separating particular co¬
lours from the mass of light, and of rendering
them visible sometimes by reflection, and, in
other cases, by transmission. As there is rea¬
son to think, then, that the minute parts, the
mere particles of all bodies, even the most
opaque, are transparent, they may very well be
DISSERTATION FOURTH.
665
conceived to act on light after the manner of the
thin plates, and to produce each, according to
its thickness and density, its appropriate colour,
which, therefore, becomes the colour of the sur¬
face. Thus the colours in which the bodies
round us appear everywhere arrayed, are redu¬
cible to the action of the parts which constitute
their surfaces on the refined and active fluid
which pervades, adorns, and enlightens the
world.
But the same experiments led to some new
and unexpected conclusions, that seemed to
reach the very essence of the fluid of which we
now speak. It was impossible to observe, with¬
out wonder, the rings alternately luminous and
dark that were formed between the two plates
of glass in the preceding experiments, and deter¬
mined to he what they were by the different
thickness of the air between the plates, and hav¬
ing to that thickness the relations formerly ex¬
pressed. A plate of which the thickness was
equal to a certain quantity multiplied by an odd
number, gave always a circle of the one kind;
but if the thickness of the plate was equal to the
same quantity multiplied by an even number, the
circle was of another kind, the light, in the first
case, being reflected, in the second transmitted.
Light penetrating a thin transparent plate, of
which the thickness was 3m, 5m, &c. was de¬
composed and reflected; the same light penetrat¬
ing the same plate, but of the thickness 0, 2m,
4m, was transmitted, though, in a certain degree,
also decomposed. The same light, therefore,
was transmitted or reflected, according as the
second surface of the plate of air through which
it passed was distant from the first by the inter¬
vals 0, 2, 4m, or m, 3m, 5m ; so that it becomes
necessary to suppose the same ray to he succes¬
sively disposed to he transmitted and to he re¬
flected at points of space separated from one
another by the same interval m. This constitutes
what Newton called Jits of easy transmission and
easy reflection, and forms one of the most singu¬
lar parts of his optical discoveries. It is so un¬
like any thing which analogy teaches us to ex¬
pect, that it has often been viewed with a degree
of incredulity, and regarded as at best but a con¬
jecture introduced to account for certain optical
DISS. IV., PART II.
phenomena. This, however, is by no means a
just conclusion ; for it is, in reality, a necessary
inference from appearances accurately observed,
and is no less entitled to he considered as a fact
than those appearances themselves. The diffi¬
culty of assigning a cause for such extraordinary
alternations cannot be denied, hut does not entitle
us to doubt the truth of a conclusion fairly de¬
duced from experiment. The principle has been
confirmed by phenomena that were unknown to
Newton himself, and possesses this great and
unequivocal character of philosophic truth, that
it has served to explain appearances which were
not observed till long after the time when it
first became known.
We cannot follow the researches of Newton
into what regards the colours of thick plates,
and of bodies in general. We must not, how¬
ever, pass over his explanation of refraction,
which is among the happiest to be met with in
any part of science, and has the merit of con¬
necting the principles of optics with those of
dynamics.
The theory from which the explanation we
speak of is deduced is, that light is an emana¬
tion of particles, moving in straight lines with
incredible velocity, and attracted by the particles
of transparent bodies. When, therefore, light
falls obliquely on the surface of such a body, its
motion may be resolved into two, one parallel
to that surface, and the other perpendicular to
it. Of these, the first is not affected by the at¬
traction of the body, which is perpendicular to
its own surface; and, therefore, it remains the
same in the refracted that it was in the incident
ray. But the velocity perpendicular to the sur¬
face is increased by the attraction of the body,
and, according to the principles of dynamics,
(the 39th, book i. Princip.) whatever be the
quantity of this velocity, its square, on entering
the same transparent body, will always he aug¬
mented by the same quantity. But it is easy to
demonstrate that, if there be two right-angled
triangles, with a side in the one equal to a side
in the other, the hypotheneuse of the first being
given, and the squares of their remaining sides
differing by a given space, the sines of the angles
opposite to the equal sides must have a given
4 P
666
PRELIMINARY DISSERTATIONS.
ratio to one another.1 This amounts to the
same with saying, that, in the case before us,
the sine of the angle of incidence is to the sine
of the angle of refraction in a given ratio.
The explanation of the law of refraction thus
given is so highly satisfactory, that it affords a
strong argument in favour of the system which
considers light as an emanation of particles from
luminous bodies, rather than the vibrations of
an elastic fluid. It is true that Huygens de¬
duced from this last hypothesis an explanation
of the law of refraction, on which considerable
praise was bestowed in the former part of this
Dissertation. It is undoubtedly very ingenious,
but does not rest on the same solid and un¬
doubted principles of dynamics with the pre¬
ceding, nor does it leave the mind so completely
satisfied. Newton, in his Principia, has deduced
another demonstration of the same optical pro¬
position from the theory of central forces.2
The different refrangihility of the rays of
light forms no exception to the reasoning above.
The rays of each particular colour have their
own particular ratio subsisting between the sines
of incidence and refraction; or, in each, the
square that is added to the square of the per¬
pendicular velocity has its own value, which
continues the same while the transparent me¬
dium is the same.
Light, in consequence of these views, became,
in the hands of Newton, the means of making
important discoveries concerning the internal
and chemical constitution of bodies. The square
that is added to that of the perpendicular velo¬
city of light in consequence of the attractive force
of the transparent substance, is properly the
measure of the quantity of that attraction, and
is the same with the difference of the squares of
the velocities of the incident and the refracted
light. This is readily deduced, therefore, from
the ratio of the angle of incidence to that of re¬
fraction ; and when this is done for different
substances, it is found that the above measure
of the refracting power of transparent bodies is
nearly proportional to their density, with the
exception of those which contain much inflam¬
mable matter in their composition, or sulphur as
it Avas then called, which is always accompanied
with an increase of refracting power.5
Thus, the refracting power, ascertained as
above, when divided by the density, gives quo¬
tients not Arery different from one another, till
we come to the inflammable bodies, where a
great increase immediately takes place. In air,
for instance, the quotient is 5208, in rock-crys¬
tal 5450, and the same nearly in common glass.
But in spirit of Avine, oil, amber, the same
quotients are 10121, 12607, 13654. Newton
found in the diamond, that this quotient is still
greater than any of the preceding, being 14556.4
Hence he conjectured, what has since been so
fully verified by experiment, that the diamond,
at least in part, is an inflammable body. Ob¬
serving, also, that the refracting power of water
is great for its density, the quotient, expounding
it as above, being 7845, he concluded, that an
inflammable substance enters into the composi¬
tion of that fluid,—a conclusion which has been
confirmed by one of the most certain hut most
unexpected results of chemical analysis. The
views thus suggested by Newton have been suc¬
cessfully pursued by future inquirers, and the
action of bodies on light is now regarded as one
of the means of examining into their internal
constitution.
I should have before remarked, that the alter¬
nate disposition to he easily reflected and easily
transmitted serves to explain the fact, that all
transparent substances reflect a portion of the
incident light. The reflection of light from the
surfaces of opaque bodies, and from the anterior
surfaces of transparent bodies, appears to he pro¬
duced by a repulsive force exerted by those sur¬
faces at a determinate hut very small distance,
in consequence of which there is stretched out
over them an elastic web, through which the par¬
ticles of light, notwithstanding their incredible
velocity, are not always able to penetrate.5 In
the case of a transparent body, the light, which,
when it arrives at this outwork, as it may be
1 Optics, book ii. part iii. prop. 10. 3 Optics, book i. part i. prop. 6.
2 Princip. Math. lib. i. prop. 94: also Optics, book i. part i. prop. 6. 4 Ibid.
6 A velocity that enables light to pass from the sun to the earth in 8' 13", as is deduced from the eclipses of Jupiter’s
satellites.
DISSERTATION FOURTH.
667
called, is in a jit of easy reflection, obeys of
course the repulsive force, and is reflected back
again. The particles, on the other hand, which
are in the state which disposes them to be trans¬
mitted, overcome the repulsive force, and, en¬
tering into the interior of the transparent body,
are subjected to the action of its attractive force,
and obey the law of refraction already explained.
If these rays, however, reach the second surface
of the transparent body (that hody being sup¬
posed denser than the medium surrounding it)
in a direction having a certain obliquity to that
surface, the attraction will not suffer the rays
to emerge into the rarer medium, but will force
them to return back into the transparent body.
Thus, the reflection of light at the second sur¬
face of a transparent body is produced, not by
the repulsion of the medium in which it was
about to enter, but by the attraction of that
which it was preparing to leave.
The first account of the experiments from,
which all these conclusions were deduced, was
given in the Philosophical Transactions for 1672,
and the admiration excited by their brilliancy
and their novelty may easily he imagined.
Among the men of science, the most enlight¬
ened were the most enthusiastic in their praise.
Huygens, writing to one of his friends, says of
them, and of the truths they were the means of
making known, <c Quorum respectu omnia hue
usque edita jejunia sunt et prorsus puerilia.” Such
were the sentiments of the person who, of all
men living, was the best able to judge, and had
the best right to be fastidious, in what related
to optical experiments and discoveries. But all
were not equally candid with the Dutch philo¬
sopher ; and though the discovery now commu¬
nicated had every thing to recommend it which
can arise from what is great, new, and singu¬
lar ; though it was not a theory or a system of
opinions, but the generalization of facts made
known by experiments; and though it was
brought forward in the most simple and unpre¬
tending form, a host of enemies appeared, each
eager to obtain the unfortunate pre-eminence
of being the first to attack conclusions which
the unanimous voice of posterity was to con¬
firm. In this contention, the envy and activity
of Hooke did not fail to give him the advantage;
and he communicated his objections to Newton’s
conclusions concerning the refrangibility of light
in less than a month after they had been read
in the Royal Society. He admitted the accuracy
of the experiments themselves, but denied that
the cause of the colour is any quality residing
permanently in the rays of light, any more than
that the sounds emitted from the pipes of an or¬
gan exist originally in the air. An imaginary
analogy between sound and light seems to have
been the basis of all his optical theories. He
conceived that colour is nothing but the dis¬
turbance of light by pulses propagated through
it; that blackness proceeds from the scarcity,
whiteness from the plenty, of undisturbed light ;
and that the prism acts by exciting different
pulses in this fluid, which pulses give rise to the
sensations of colour. This obscure and unin¬
telligible theory (if we may honour what is un¬
intelligible with the name of a theory) he ac¬
companied with a multitude of captious objec¬
tions to the reasonings of Newton, whom he was
not ashamed to charge with borrowing from him
without acknowledgement. To all this Newton
replied, with the solidity, calmness, and modes¬
ty, which became the understanding and the
temper of a true philosopher.
The new theory of colours was quickly as¬
sailed by several other writers, who seem all to
have had a better apology than Hooke for the
errors into which they fell. Among them one
of the first was Father Pardies, who wrote
against the experiments, and what he was pleased
to call the hypothesis, of Newton. A satisfac¬
tory and calm reply convinced him of his mis¬
take, which he had the candour very readily to
acknowledge. A countryman of his, Mariotte,
was more difficult to be reconciled, and, though
very conversant with experiment, appears never
to have succeeded in repeating the experiments
of Newton. Desaguliers, at the request of the
latter, repeated the experiments doubted of be¬
fore the Royal Society, where Monmort, a coun¬
tryman and a friend of Mariotte, was present.1
MM. Linus and Lucas, both of Liege, object-
668
PRELIMINARY DISSERTATIONS.
ed to Newton’s experiments as inaccurate; tlie
first, because, on attempting to repeat them, be
had not obtained the same results; and the se¬
cond, because he had not been able to perceive
that a red object and a blue required the focal
distance to be different when they were viewed
through a telescope. Newton replied with great
patience and good temper to both.
The series was closed in 1727, by the work of
an Italian author, Rizetti, who, in like manner,
called in question the accuracy of experiments
which he himself had not been able to repeat.
Newton was now no more; but Desaguliers, in
consequence of Rizetti’sdoubts, instituteda series
of experiments which seemed to set the matter
entirely at rest. These experiments are de¬
scribed in the Philosophical Transactions for
1728.
An inference which Newton had immediately
drawn from the discoveries above described was,
that the great source of imperfection in the re¬
fracting telescope was the different refrangibility
of the rays of light, and that there were stronger
reasons than either Mersenne or Gregory had
suspected, for looking to reflection for the im¬
provement of optical instruments. It was evi¬
dent, from the different refrangibility of light,
that the rays coming from the same point of an
object, when decomposed by the refraction of a
lens, must converge to different foci; the red
rays, for example, to a point more distant from
the lens, and the violet to one nearer by about
a fifty-fourth part of the focal distance. Hence
it was not merely from the aberration of the
rays caused by the spherical figure of the lens
that the imperfection of the images formed by
refraction arose, but from the very nature of re¬
fraction itself. It was evident, at the same
time, that in a combination of lenses with oppo¬
site figures, one convex, for instance, and ano¬
ther concave, there was a tendency of the two
contrary dispersions to correct one another.
But it appeared to Newton, on examining dif¬
ferent refracting substances, that the dispersion
of the coloured rays never could be corrected
except when the refraction itself was entirely
destroyed; for he thought he had discovered
that the quantity of the refraction and of the
dispersion in different substances bore always
the same proportion to one another. This is
one of the few instances in which his conclusions
have not been confirmed by subsequent experi¬
ment ; and it will, accordingly, fall under dis¬
cussion in another part of this Dissertation.
Having taken the resolution of constructing
a reflecting telescope, he set about doing so with
his own hands. There was, indeed, at that
time, no other means by which such a work
could be accomplished; the art of the ordinary
glass-grinder not being sufficient to give to me¬
tallic specula the polish which was required. It
was on this account that Gregory had entirely
failed in realizing his very ingenious optical in¬
vention.
Newton, however, himself possessed excellent
hands for mechanical operations, and could use
them to better purpose than is common with
men so much immersed in deep and abstract
speculation. It appears, indeed, that mechani¬
cal invention was one of the powers of his mind
which began to unfold itself at a very early pe¬
riod. In some letters subjoined to a Memoir
drawn up after his death by his nephew Conduit,
it is said, that, when a boy, Newton used to
amuse himself with constructing machines, mills,
&c. on a small scale, in which he displayed
great ingenuity; and it is probable that he then
acquired that use of his hands which is so diffi¬
cult to be learned at a later period. To this,
probably, we owe the neatness and ingenuity
with which the optical experiments above re¬
ferred to were contrived and executed,—experi¬
ments of so difficult a nature, that any error in
the manipulation would easily defeat the effect,
and appears actually to have done so with many
of those who objected to his experiments.1
1 The Memoir of Conduit was sent to Fontenelle when he was preparing the Eloge on Newton, hut he seems o a
paid little attention to it, and has passed over the early part of his life with the remark, that one may apply to im w
Lucan says of the Nile, that it has not been “ permitted to mortals to see that river in a feeble state.” It the letters a
referred to had formed a part of this communication, I think the Secretary of the Academy would ha.ve sacimce a
comparison to an instructive fact. In other respects Conduit’s Memoir did not convey much information that cou
use. His instructions to Fontenelle are curious enough ; he bids him be sure to state, that Leibnitz had horrowe
Differential Calculus from the Method of Fluxions. He conjured him in another place not to omit to mention, that W,u
DISSERTATION FOURTH.
669
He succeeded perfectly in the construction of
his telescope; and his first communication with
Oldenburg-, and the first reference to his optical
experiments, is connected with the construction
of this instrument, and mentioned in a letter
dated the 11th January 1672. He had then
been proposed as a member of the Royal Socie¬
ty by the bishop of Sarum, and he says, “ If
the honour of being a member of the Society
shall be conferred on me, I shall endeavour to
testify my gratitude by communicating what my
poor and solitary endeavours can effect toward
the promoting its philosophical designs.”1 Such
was the modesty of the man who was to effect a
greater revolution in the state of our knowledge
of nature than any individual had yet done, and
greater, perhaps, than any individual is ever des¬
tined to bring about. Success, however, never
altered the temper in which he began his re¬
searches.
Newton, after considering the reflection and re¬
fraction of light, proceeded, in the third and last
book of his Optics, to treat of its inflection, a sub¬
ject which, as has been remarked in the former
part of this Dissertation, was first treated of by
Grimaldi. Newton having admitted a ray of light
through a hole in a window-shutter into a dark
chamber, made it pass by the edge of a knife,
or, in some experiments, between the edges of
two knives, fixed parallel and very near to one
another; and, by receiving the light on a sheet
of paper at different distances behind the knives,
he observed the coloured fringes which had been
described by the Italian optician, and, on ex¬
amination, found that the rays had been acted
on in passing the knife-edges both by repulsive
and attractive forces, and had begun to be so
acted on in a sensible degree when they were
yet distant by of an inch of the edges of the
knives. His experiments, however, on this sub¬
ject were interrupted, as he informs us, and do
not appear to have been afterwards resumed.
They enabled him, however, to draw this con¬
clusion, that the path of the ray, in passing by
the knife-edge, was bent in opposite directions,
so as to form a serpentine line, convex and con¬
cave toward the knife, according to the repulsive
or attractive forces which acted at different dis¬
tances; that it was also reasonable to conclude,
that the phenomena of the refraction, reflection,
and inflection of light were all produced by the
same force variously modified, and that they did
not arise from the actual contact or collision of
the particles of light with the particles of bodies.
The third book of the Optics concludes with
those celebrated Queries which carry the mind
so far beyond the bounds of ordinary specula¬
tion, though still with the support and under
the direction either of direct experiment or close
analogy. They are a collection of propositions
relative chiefly to the nature of the mutual
action of light and of bodies on one another,
such as appeared to the author highly pro¬
bable, yet wanting such complete evidence as
might entitle them to be admitted as principles
established. Such enlarged and comprehensive
views, so many new and bold conceptions, were
never before combined with the sobriety and cau¬
tion of philosophical induction. The anticipa¬
tion of future discoveries, the assemblage of so
many facts from the most distant regions of
human research, all brought to bear on the same
points, and to elucidate the same questions, are
never to be sufficiently admired. At the mo¬
ment when they appeared, they must have pro¬
duced a wonderful sensation in the philosophic
world, unless, indeed, they advanced too far be¬
fore the age, and contained too much which the
comment of time was yet required to elucidate.
It is in the Queries that we meet with the
ideas of this philosopher concerning the Elastic
Ether, which he conceived to be the means of
Caroline used to delight much in the conversation of Newton, and nothing could do more honour to Newton than the com¬
mendation of a Queen, the Minerva of her age. Fontenelle was too much a philosopher and a man of the world, and had
himself approached too near to the persons of princes, to be of Mr Conduit’s opinion, or to think that the approbation of
the most illustrious princess could add dignity to the man who had made the three greatest discoveries yet known, and in
whose hands the sciences of Geometry, Optics, and Astronomy, had all taken new forms. If he had been called to write
the Eloge of the Queen of England, he would, no doubt, have remarked her relish for the conversation of Newton.
On the whole, the Eloge on Newton has great merit, and, to be the work of one who was at bottom a Cartesian, is a sin¬
gular example of candour and impartiality.
1 Birch’s History of the Royal Society, vol. III. p. 3.
670
PRELIMINARY DISSERTATIONS.
conveying the action of bodies from one part of
the universe to another, and to which the phe¬
nomena of light, of heat, of gravitation, are to
he ascribed. Here we have his conclusions con¬
cerning that polarity or peculiar virtue residing
in the opposite sides of the rays of light, which
he deduced from the enigmatical phenomena of
doubly-refracting crystals. Here, also, the first
step is made toward the doctrine of elective at¬
tractions or of chemical affinity, and to the no¬
tion, that the phenomena of chemistry, as well
as of cohesion, depend on the alternate attrac¬
tions and repulsions existing between the par¬
ticles of bodies at different distances. The com¬
parison of the gradual transition from repulsion
to attraction at those distances, with the posi¬
tive and negative quantities in algebra, was first
suggested here, and is the same idea which the
ingenuity of Boscovich afterwards expanded into
such a beautiful and complete system. Others
who have attempted such flights had ended in
mere fiction and romance: it is only for such
men as Bacon or Newton to soar beyond the re¬
gion of poetical fiction, still keeping sight of
probability, and alighting again safe on the ter¬
ra jirma of philosophic truth.1
SECTION IV.
ASTRONOMY.
The time was now come when the world was
to be enlightened by a new science, arising out
of the comparison of the phenomena of motion
as observed in the heavens, with the laws of
motion as known on the earth. Physical astro¬
nomy was the result of this comparison; a science
embracing greater objects, and destined for a
higher flight, than any other branch of natural
knowledge. It is unnecessary to observe, that it
was by Newton that the comparison just refer¬
red to was instituted, and the riches of the new
science unfolded to mankind.
This young philosopher, already signalized by
great discoveries, had scarcely reached the age
of twenty-four, when a great public calamity
forced him into the situation where the first step
in the new science is said to have been suggest¬
ed ; and that, by some of those common appear¬
ances in which an ordinary man sees nothing to
draw his attention, nor even the man of genius,
except at those moments of inspiration when
the mind sees farthest into the intellectual world.
In 1666, the plague forced him to retire from
Cambridge into the country; and, as he sat one
day alone, in a garden, musing on the nature of
the mysterious force by which the phenomena
at the earth’s surface are so much regulated, he
observed the apples falling spontaneously from
the trees, and the thought occurred to him,—
since gravity is a tendency not confined to
bodies on the very surface of the earth, but
reaching to the tops of trees, to the tops of the
highest buildings, nay, to the summits of the
most lofty mountains, without its intensity or
direction suffering any sensible change, why
may it not reach to a much greater distance,
and even to the moon itself? And, if so, may
not the moon he retained in her orbit by gravity,
1 16 optical works ol Jsewton are not often to be found all brought together into one body. The first part of them
consists ot the papers in the Philosophical Transactions, which gave the earliest account of his discoveries, and which have
been alrea y reterred to. I hey are in the *orm of Letters to Oldenburg, the Secretary of the Societv, as are also the an¬
swers to Hooke and the others who objected to these discoveries ; the whole forming a most interesting and valuable
series, which Dr Horsley has published in the fourth volume of his edition of .Newton’s works, under the title of Letters re¬
lating to the Theory of Light and Colours. The next work, in point of time, consists of the Lectiones Opticce, or the optical
lectures which the author delivered at C mbridge. The Optics, in three books, is the last and most complete, containing
all the leasonmg concerning optical phenomena above referred to. The first edition was in 1704 : the second, with addi¬
tions, m 1717- Newtoni Ojjera, tom. IV. Horsley’s edition.
DISSERTATION FOURTH.
671
and forced to describe a curve like a projectile
at the surface of the earth ?1
Here another consideration very naturally oc¬
curred. Though gravity he not sensibly weak¬
ened at the small distances from the surface to
which our experiments extend, it may be weak¬
ened at greater distances, and at the moon may
he greatly diminished. To estimate the quan¬
tity of this diminution, Newton appears to have
reasoned thus : If the moon he retained in her
orbit by her gravitation to the earth, it is pro¬
bable that the planets are, in like manner, car¬
ried round the sun by a power of the same kind
with gravity} directed to the centre of that lu¬
minary. He proceeded, therefore, to inquire
by what law the tendency or gravitation of the
planets to the sun must diminish, in order that,
describing, as they do, orbits nearly circular
round the sun, their times of revolution and
their distances may have the relation to one an¬
other which they are known to have from ob¬
servation, or from the third law of Kepler.
This was an investigation which, to most even
of the philosophers and mathematicians of that
age, would have proved an insurmountable ob¬
stacle to their further progress; but Newton was
too familiar with the geometry of evanescent or
infinitely small quantities, not to discover very
soon that the law now referred to would require
the force of gravity to diminish exactly as the
square of the distance increased. The moon,
therefore, being distant from the earth about
sixty semidiameters of the earth, the force of
gravity at that distance must he reduced to the
3600th part of what it is at the earth’s surface.
Was the deflection of the moon then from the
tangent of her orbit, in a second of time, just
the 3600th part of the distance which a heavy
body falls in a second at the surface of the
earth ? This was a question that could be pre¬
cisely answered, supposing the moon’s distance
known, not merely in semidiameters of the earth,
hut in feet, and her angular velocity, or the time
of her revolution in her orbit, to be also known.
In this calculation, however, being at a dis¬
tance from hooks, he took the common estima¬
tion of the earth’s circumference that was in
use before the measurement of Norwood or of
the French Academicians, according to which a
degree is held equal to 60 English miles. This
being in reality a very erroneous supposition,
the result of the calculation did not represent
the force as adequate to the supposed effect;
whence Newton concluded that some other
cause than gravity must act on the moon, and
on that account he laid aside, for the time, all
further speculation on the subject. It was in
the true spirit of philosophy that he so readily
gave up an hypothesis, in which he could not
but feel some interest, the moment he found it
at variance with observation. He was sensible
that nothing but the exact coincidence of the
things compared could establish the conclusion
he meant to deduce, or authorize him to pro¬
ceed with the superstructure, for which it was
to serve as the foundation.
It appears, that it was not till some years
after this that his attention was called to the
same subject, by a letter from Dr Hooke, pro¬
posing, as a question, To determine the line
in which a body let fall from a height descends
to the ground, taking into consideration the
motion of the earth on its axis. This induced
him to resume the subject of the moon’s motion;
and the measure of a degree by Norwood having
now furnished more exact data, he found that
his calculation gave the precise quantity for the
moon’s momentary deflection from the tangent
of her orbit, which was deduced from astrono¬
mical observation. The moon, therefore, has a
tendency to descend toward the earth, from the
same cause that a stone at its surface has; and
if the descent of the stone in a second be dimi¬
nished in the ratio of 1 to 3600, it will give the
quantity by which the moon descends in a se¬
cond, below the tangent to her orbit • and thus
is obtained an experimental proof of the fact,
that gravity decreases as the square of the dis¬
tance increases. He had already found that the
times of the planetary revolutions, supposing
their orbits to be circular, led to the same con¬
clusion ; and he now proceeded, with a view to
the solution of Hooke’s problem, to inquire what
their orbits must be, supposing the centripetal
1 Pembertox’s View of Newton's Philosophy, Pref.
672
PRELIMINARY DISSERTATIONS.
force to be inversely as the square of the dis¬
tance, and the initial or projectile force to he
any whatsoever. On this subject, Pembeiton
says, he composed (as he calls it) a dozen pro¬
positions, which probably were the same with
those in the beginning of the Principia^ such
as the description of equal areas in equal times,
about the centre of force, and the ellipticity of
the orbits described under the influence of a
centripetal force that varied inversely as the
squares of the distances.
What seems very difficult to he explained is,
that after having made trial of his strength,
and of the power of the instruments of investi¬
gation which he was now in possession of, and
had entered by means of them on the noblest
and most magnificent field of investigation that
was ever yet opened to any of the human race,
he again desisted from the pursuit, so that it
was not till several years afterwards that the
conversation of Dr Halley, who made him a
visit at Cambridge, induced him to resume and
extend his researches.
He then found, that the three great facts in
astronomy, which form the laws of Kepler,
gave the most complete evidence to the system
of gravitation. The first of them, the propor¬
tionality of the areas described by the radius
vector to the times in which they are described,
is the peculiar character of the motions pro¬
duced by an original impulse impressed on a
body, combined with a centripetal force contin¬
ually urging it to a given centre. The second
law, that the planets describe ellipses, having
the sun in one of the foci, common to them all,
coincides with this proposition, that a body under
the influence of a centripetal force, varying as
the square of the distance inversely, and having
any projectile force whatever originally im¬
pressed on it, must describe a conic section
having one focus in the centre of force, which
section, if the projectile force does not exceed a
certain limit, will become an ellipse. The third
law, that the squares of the periodic times are
as the cubes of the distances, is a property which
belongs to the bodies describing elliptic orbits
under the conditions just stated. Thus the three
great truths to which the astronomy of the
planets had been reduced by Kepler, were all
explained in the most satisfactory manner, by
the supposition that the planets gravitate to the
sun with a force which varies in the inverse
ratio of the squares of the distances. It added
much to this evidence, that the observations of
Cassini had proved the same laws to prevail
among the satellites of Jupiter.
But did the principle which appeared thus to
unite the great bodies of the universe act only
on those bodies ? Did it reside merely in their
centres, or was it a force common to all the
particles of matter? Was it a fact that every
particle of matter had a tendency to unite with
every other ? Or was that tendency directed only
to particular centres ? It could hardly he doubt¬
ed that the tendency was common to all the par¬
ticles of matter. The centres of the great bodies
had no properties as mathematical points; they
had none hut what they derived from the mate¬
rial particles distributed around them. But the
question admitted of being brought to a better
test than that of such general reasoning as the
preceding. The bodies between which this ten¬
dency had been observed to take place were all
round bodies, and either spherical or nearly so;
but whether great or small, they seemed to
gravitate toward one another according to the
same law. The planets gravitated to the sun,
the moon to the earth, the satellites of Jupiter
toward Jupiter; and gravity, in all these in¬
stances, varied inversely as the squares of the
distances. Were the bodies ever so small—were
they mere particles—provided only they were
round, it was therefore safe to infer, that they
would tend to unite with forces inversely as the
squares of the distances. It was probable, then,
that gravity was the mutual tendency of all the
particles of matter toward one another; but this
could not be concluded with certainty, till it was
found whether great spherical bodies, composed
of particles gravitating according to this law,
would themselves gravitate according to the
same. Perhaps no man of that age but Newton
himself was fit to undertake the solution of this
problem. His analysis, either in the form of flux¬
ions or in that of prime and ultimate ratios, was
able to reduce it to the quadrature of curves; and
he then found, no doubt infinitely to his satisfac¬
tion, that the law was the same for the sphere as
DISSERTATION FOURTH.
673
for the particles which compose it ; that the different orbits is as the mean distance divided
gravitation was directed to the centre of the by the square of the periodic time; and the same
sphere,, and was as the quantity of matter con- intensity being also as the quantities of matter
ame . in it, di\ ided by the square of the distance divided by the squares of the distances, it follows
its centre. Thus a complete expression that these two quotients are equal to one another,
was obtained, for the law of gravity, involving and that, therefore, the quantities of matter are
o 11 io conditions on which it must depend, the as the mean distances divided by the squares of
quantity of mattei in the gravitating bodies, and the periodic times. Supposing, therefore, in the
t e distance at which the bodies were placed, instance just mentioned, that the ratio of the
There could be no doubt that this tendency was mean distance of the sun from the earth to the
always, mutual, as there appeared nowhere any mean distance of the moon from the earth is
exception to the rule that action and re-action given (which it is from astronomical observa-
are equal; so that if a stone gravitated to the tion); as the ratio of their periodic lines is also
earth, the earth gravitated equally to the stone ; known, the ratio of the quantity of matter in the
that is to say, the two bodies tended to ap- sun to the quantity of matter in the earth, of
proach one another with velocities which were consequence, is found; and the same holds good
inversely as their quantities of matter.1 There for all the planets which have satellites moving
appeared to be no limit to the distance to which round them. Nothing certainly can be more
this action reached ; it was a force that united unexpected than that the quantities of matter in
all the parts of matter to one another; and if it bodies so remote should admit of being compared
appeared to be particularly directed to certain with one another, and with the earth. Hence
points, such as the centres of the sun or of the also their mean densities, or mean specific gra-
planets, it was only on account of the quantity vities, became known. For from their distances
of matter collected and distributed uniformly and the angles they subtended, both known from
round those points, through which, therefore, observation, their magnitudes or cubical contents
the force resulting from the composition of all were easily inferred; and the densities of all
those elements must pass either accurately or bodies are, as their quantities of matter, divided
nearly. . by their magnitude. The Principia Philosophice
. A remarkable inference was deduced from this Naturalis, which contained all these discoveries,
view of the planetary motions, giving a deep in- and established the principle of universal gravi-
sight into the constitution of our system in a tation was given to the world in 1687, an era,
matter that seems the most recondite, and the on that account, for ever memorable in the his-
farthest beyond the sphere which necessarily tory of human knowledge,
circumscribes human knowledge. The quantity The principle of gravity, which was thus fully
of matter, and even the density of the planets, established, aud its greatest and most extensive
was determined. We have seen how Newton consequences deduced, was not now mentioned
compared the intensity of gravitation at the sur- for the first time, though for the first time its
face of the earth with its intensity at the moon; existence as a fact was ascertained, and the law
and by a computation somewhat similar, he com- it observes was discovered. Besides some curi-
pared the intensity of the earth’s gravitation to ous references to weight and gravity, contained
the sun with the moon’s gravitation to the earth, in the writings of the ancients, we find some-
each being measured by the contemporaneousand thing more precise concerning it in the writings
momentary deflection from a tangent to the small of Copernicus, Kepler, and Hooke,
arch of its orbit. A more detailed investigation Anaxagoras is said to have held that “ the
showed, that the intensity of the central force in heavens are kept in their place by the rapidity
If M and M are the masses of two spheres, and x the distance of their centres, -l+)M- is the accelerating force
with which they tend to unite ; but the velocity of the approach of M will be and of M' -M.
DISS. IV. PART II. a n
674
preliminary dissertations.
of their revolution, and would fall down if that
rapidity were to cease.”1
Plutarch, in like manner, says the moon is
kept from falling hy the rapidity of her motion,
just as a stone whirled round in a sling is pre¬
vented from falling to the ground.2
Lucretius, reasoning probably after Democri¬
tus, holds, that the atoms would all, from their
gravity, have long since united in the centre of
the universe, if the universe were not infinite,
so as to have no centre.3
An observation of Pythagoras, supposed to
refer to the doctrine of gravity, though in real¬
ity extremely vague, has been abundantly com¬
mented on hy Gregory and Maclaurin. A mu¬
sical string, said that philosopher, gives the
same sound with another of twice the length, if
the latter he straitened hy four times the weight
that straitens the former; and the gravity of a
planet is four times that of another which is at
twice the distance. These are the most precise
notices, as far as I know, that exist in the writ¬
ings of the ancients concerning gravity as a force
acting on terrestrial bodies, or as extending even
to those that are more distant. They are the
reveries of ingenious men who had no steady
principles deduced from experience and obser¬
vation to direct their inquiries, and who, even
when in their conjectures they hit on the truth,
could hardly distinguish it from error.
Copernicus, as might he expected, is consi¬
derably more precise. “ I do not think,” says
he, “ that gravity is anything hut a natural ap¬
petency of the parts (of the earth) given hy the
providence of the Supreme Being, that, hy unit¬
ing together, they may assume the form of a
globe. It is probable that this same affection
belongs to the sun, the moon, and the fixed
stars, which are all of a round form.”4
The power which Copernicus here speaks of
has nothing to do, in his opinion, with the revo¬
lutions of the earth or the planets in their dif¬
ferent orbits. It is merely intended as an ex¬
planation of their globular forms; and the con¬
sideration that does the author most credit is
that of supposing the force to belong, not to
the centre, hut to all the parts of the earth.
Kepler, in his immortal work on the Motions
of Mars, treats of gravity as a force acting na¬
turally from planet to planet, and particularly
from the earth to the moon. “ If the moon and
the earth were not retained hy some animal or
other equivalent force each in its orbit, the
earth would ascend to the moon hy a 54th part
of the interval between them, while the moon
moved over the remaining 53 parts, that is, sup¬
posing them both of the same density.”5 This
passage is curious, as displaying a singular mix¬
ture of knowledge and error on the subject of
the planetary motions. The tendency of the
earth and moon being mutual, and producing
equal quantities of motion in those bodies, be¬
speaks an accurate knowledge of the nature
of that tendency, and of the equality, at least
in this instance, between action and re-action.
Then, again, the idea of an animal force, or
some other equally unintelligible power, being
necessary to carry on the circular motion, and
to prevent the bodies from moving directly to¬
ward each other, is very strange; considering
that Kepler knew the inertia of matter, and
ought therefore to have understood the nature
of centrifugal force, and its power to counteract
the mutual gravitations of the two bodies. In
this respect the great astronomer, who was lay¬
ing the foundation of all that is known of the
heavens, was not so far advanced as Anaxago¬
ras and Plutarch;—so slow and unequal are the
steps by which science advances to perfection.
The mutual gravity of the earth and moon is
not supposed by Kepler to have any concern in
the production of their circular motions ; yet he
holds the tides to be produced by the gravita¬
tion of the waters of the sea toward the moon.6
The length to which Galileo advanced in this
direction, and the point at which he stopped,
1 Coelum omne vehementi circuitu constare, alias remissione lapsurum. (Diog. Lae tit. in Anax. lib. ii. sect. 12.)
2 De Facie in Orbe Lnnae.
2 Lib. i. v. 983.
4 De Revolutionibus Orbium Ccelestium, lib. i. cap. ix. p. 17-
s On that supposition their quantities of matter would be as their bulks, or as 1 to 53.
6 Astronomia Stellce Martis, Introd. parag. 8.
DISSERTATION FOURTH.
675
are no less curious to be remarked. Though so
well acquainted with the nature of gravity on
the earth’s surface, the object of so many of
his researches and discoveries,—and though he
conceived it to exist in all the planets, nay, in
all the celestial bodies, and to be the cause of
their round figure, he did not believe it to be a
power that extended from one of those bodies to
another. He seems to have thought that gravity
was a principle which reg'ulated the domestic
economy of each particular body, but had no¬
thing to do with their external relations; so
that he censured Kepler for supposing that the
phenomena of the tides are produced by the
gravitation of the waters of the ocean to the
moon.1
Hooke did not stop short in the same unac¬
countable manner, but made a nearer approach
to the truth than any one had yet done. In his
attempt to prove the motion of the earth, pub¬
lished in 1674, he lays it down as the principle
on which the celestial motions are to be ex¬
plained, that the heavenly bodies have an attrac¬
tion or gravitation toward their own centres,
which extends to other bodies within the sphere
of their activity; and that all bodies would
move in straight lines, if some force like this
did not act on them continually, and compel
them to describe circles, ellipses, or other curve
lines. The force of gravity, also, he considered
as greatest nearest the body, though the law of
its variation he could not determine. These are
great advances;—though, from his mention of
the sphere of activity, from his considering the
force as residing in the centre, and from his ig¬
norance of the law which it observed, it is evi-
-dent that, besides great vagueness, there was
much error in his notions about gravity. Hooke,
however, whose candour and uprightness bore
no proportion to the strength of his understand¬
ing, was disingenuous enough, when Newton
had determined that law, to lay claim himself
to the discovery.
This is the farthest advance that the know¬
ledge of the cause of the celestial motions had
made before the investigations of Newton : it is
the precise point at which this knowledge had
stopped, having met with a resistance which
required a mathematician armed with all the
powers of the new analysis to overcome. The
doctrine of gravity was yet no more than a con¬
jecture, of the truth or falsehood of which the
measurements and reasonings of geometry could
alone determine.
Thus, then, we are enabled accurately to per¬
ceive in what Newton’s discovery consisted. It
was in giving the evidence of demonsti’ation to
a principle which a few sagacious men had been
sufficiently sharp-sighted to see obscurely or in¬
accurately, and to propose as a mere conjecture.
In the history of human knowledge, there is
hardly any discovery to which some gradual
approaches had not been made before it was
completely brought to light. To have found
out the means of giving certainty to the thing
asserted, or of disproving it entirely, and, when
the reality of the principle was found out, to
measure its quantity, to ascertain its laws, and
to ti’ace their consequences with mathematical
precision,—in this consists the great difficulty
and the great merit of such a discovery as that
which is now before us. In this Newton had no
competitor: envy was forced to acknowledge
that he had no rival, and consoled itself with
supposing that he had no j udge.
Of all the physical principles that have yet
been made known, there is none so fruitful in
consequences as that of gravitation; but the
same skill that had directed Newton to the dis¬
covery was necessary to enable him to trace its
consequences.
The mutual gravitation of all bodies being ad¬
mitted, it was evident, that while the planets
were describing their orbits round the greatest
and most powerful body in the system, they
must mutually attract one another; and thence,
in their revolutions, some irregularities, some
deviations from the description of equal areas in
equal times, and from the laws of the elliptic
motion, might be expected. Such irregularities,
however, had not been observed at that time in
the motion of any of the planets, except the
moon, where some of them were so conspicuous
as to have been known to Hipparchus and
1 Dialogo iv.: Opere, tom. IV. p. 325. Padova, 1744, 4 tom. 4to.
676
PRELIMINARY DISSERTATIONS.
Ptolemy. Newton, therefore, was very natu¬
rally led to inquire what the different forces
were, which, according to the laws just esta¬
blished, could produce irregularities in the case
of the moon’s motion. Beside the force of the
earth, or rather of the mutual gravitation of the
moon and earth, the moon must he acted on by
the sun; and the same force which was suffi¬
cient to bend the orbit of the earth into an el¬
lipse, could not but have a sensible effect on the
orbit of the moon. Here Newton immediately
observed, that it is not the whole of the force
which the sun exerts cn the moon that disturbs
her motion round the earth, but only the differ¬
ence between the force just mentioned and that
which the sun exerts on the earth ; for it is only
that difference that affects the relative positions
of the two bodies. To have exact measures of
the disturbing forces, he supposed the entire
force of the sun on the moon to be resolved into
two, of which one always passed through the
centre of the earth, and the other was always
parallel to the line joining the sun and earth,—
consequently, to the direction of the force of the
sun on the earth. The former of these forces
being directed to the centre of the earth, did
not prevent the moon from describing equal
areas in equal times round the earth. The ef¬
fect of it on the whole, however, he showed to
be, to diminish the gravity of the moon to the
earth by about one 358th part, and to increase
her mean distance in the same proportion, and
her angular motion by about a 179111.
From the moon thus gravitating to the centre
of the earth, not by a force that is altogether in¬
versely as the square of the distance, but by
such a force diminished by a small part that va¬
ries simply as the distance, it was found, from a
very subtile investigation, that the dimensions of
the elliptic orbit would not be sensibly changed,
but that the orbit itself would be rendered
movable, its longer axis having an angular and
progressive motion, by which it advanced over
a certain arc during each revolution of the moon.
This afforded an explanation of the motion of
the apsides of the lunar orbit which had been
observed to go forward at the rate of 3° 4' near¬
ly, during the time of the moon’s revolution, in
respect of the fixed stars.
This was a new proof of the reality of the
principle of gravitation, which, however, was
rendered less conclusive by the consideration
that the exact quantity of the motion of the ap¬
sides observed did not come out from the dimi¬
nution of the moon’s gravity as above assigned.
There was a sort of cloud, therefore, which hung
over this point of the lunar theory, to dissipate
which required higher improvements in the cal¬
culus than it was given to the inventor himself
to accomplish. It was not so with respect to
another motion to which the plane of the lunar
orbit is subject, a phenomenon which had been
long known in consequence of its influence on
the eclipses of the sun and moon. This was the
retrogradation of the line of nodes, amounting
to 3' 10" every day. Newton showed that the
second of the forces into which the solar action
is moved being exerted, not in the plane of the
moon’s orbit, but in that of the ecliptic, inclined
to the former at an angle somewhat greater than
five degrees, its effect must be to draw down the
moon to the plane of the ecliptic sooner than it
would otherwise arrive at it; in consequence of
which, the intersection of the two planes would
approach, as it were, toward the moon, or move
in a direction opposite to that of the moon’s mo¬
tion, or become retrograde. From the quantity
of the solar force, and the inclination of the
moon’s orbit, Newton determined the mean
quantity of this retrogradation, as well as the
irregularities to which it is subject, and found
both to agree very accurately with observation.
Another of the lunar inequalities,—that dis¬
covered by Tycho, and called by him the Vari¬
ation, which consists in the alternate accelera¬
tion and retardation of the moon in each quarter
of her revolution,—was accurately determined
from theory, such as it is found by observation;
and the same is true as to the annual equation,
which had been long confounded with the equa¬
tion of time. With regard to the other inequa¬
lities, it does not appear that Newton attempted
an exact determination of them, but satisfied
himself with this general truth, that the prin¬
ciple of the sun’s disturbing force led to the sup¬
position of inequalities of the same kind with
those actually observed, though whether of the
same exact quantity it must be difficult to deter-
DISSERTATION FOURTH.
677
mine. It was reserved, indeed, for a more per¬
fect state of the calculus to explain the whole of
those irregularities, and to deduce their precise
value from the theory of gravity. Theory has
led to the knowledge of many inequalities,
which observation alone would have been un¬
able to discover.
While Newton was thus so successfully occu¬
pied in tracing the action of gravity among those
distant bodies, he did not, it may be supposed,
neglect the consideration of its effects on the ob¬
jects which are nearer us, and particularly on
the figure of the earth. We have seen that,
even with the limited views and imperfect in¬
formation which Copernicus possessed on this
subject, he ascribed the round figure of the earth
and of the planets to the force of gravity residing
in the particles, of these bodies. Newton, on the
other hand, perceived that, in the earth, another
force was combined with gravity, and that the
figure resulting from that combination could not
be exactly spherical. The diurnal revolution of
the earth, he knew, must produce a centrifugal
force, which would act most powerfully on the
parts most distant from the axis. The amount
of this centrifugal force is greatest at the equa¬
tor ; and being measured by the momentary re¬
cess of any point from the tangent, which was
known from the earth’s rotation, it could he com¬
pared with the force of gravity at the same
place, measured in like manner by the descent
of a heavy body in the first moment of its fall.
When Newton made this comparison, he found
that the centrifugal force at the equator is the
289th part of gravity, diminishing continually
as the cosine of the latitude, on going from thence
toward the poles, where it ceases altogether.
From the combination of this force, though small,
with the force of gravity, it follows, that the line
in which bodies actually gravitate, or the plumb
line, cannot tend exactly to the earth’s centre,
and that a true horizontal line, such as is drawn
by levelling, if continued from either pole, in
the plane of a meridian all round the earth,
would not be a circle, but an ellipse, having its
greatest axis in the plane of the equator, and its
least in the direction of the axis of the earth’s
rotation. Now, the surface of the ocean itself
actually traces this level as it extends from the
equator to either pole. The terraqueous mass
which we call the globe must therefore be what
geometers call an oblate spheroid, or a solid
generated by the revolution of the elliptic meri¬
dian about its shorter axis.
In order to determine the proportion of the
axes of this spheroid, a problem, it will readily
be believed, of no ordinary difficulty, Newton
conceived, that if the waters at the pole and at
the equator were to communicate by a canal
through the interior of the earth, one branch
reaching from the pole to the centre, and the
other at right angles to it from the centre to
the circumference of the equator, the water in
this canal must be in equilibrio, or the weight of
fluid in the one branch just equal to that in the
other. Including, then, the consideration of the
centrifugal force which acted on one of the
branches but not on the other, and considering,
too, that the figure of the mass being no longer
a sphere, the attraction must not be supposed to
be directed to the centre, but must be consider¬
ed as the result of the action of all the particles
of the spheroid on the fluid in the canals,—by a
Very subtile process of reasoning, Newton found
that the longer of the two canals must be to the
shorter as 230 to 229. This, therefore, is the
ratio of the radius of the equator to the polar
semiaxis, their difference amounting, according
to the dimensions then assigned to the earth, to
about English miles. In this investiga¬
tion the earth is understood to be homogeneous,
or everywhere of the same density.
It is very remarkable, that though the ingeni¬
ous and profound reasoning on which this con¬
clusion rests is not entirely above objection, and
assumes some things without sufficient proof,
yet, when these defects were corrected in the
new investigations of Maclaurin and Clairaut,
the conclusion, supposing the earth homogene¬
ous, remained exactly the same. The sagacity
of Newton, like the Genius of Socrates, seemed
sometimes to inspire him with wisdom from an
invisible source. By a profound study of na¬
ture, her laws, her analogies, and her resources,
he seems to have acquired the same sort of tact
or feeling in matters of science, that experienced
engineers and other artists sometimes acquire in
matters of practice, by which they are often di-
678
preliminary dissertations.
rected right, when they can scarcely describe in
words the principle on which they proceed.
From the figure of the earth thus determined,
he showed that the intensity of gravity at any
point of the surface is inversely as the distance
of that point from the centre; and its increase,
therefore, on going from the equator to the poles,
is as the square of the sine of the latitude, the
same ratio in which the degrees of the meridian
increase.1 As the intensity of gravity diminish¬
ed on going from the poles to the equator, or
from the higher to the lower latitudes, it follow¬
ed that a pendulum of a given length would
vibrate slower when carried from Europe into
the torrid zone. The observations of the two
French astronomers Varin and De Hayes, made
at Cayenne and Martinique, had already confirm¬
ed this conclusion.
The problem which Newton had thus resolved
enabled him to resolve one of still greater diffi¬
culty. The precession, that is, the retrograda-
tion, of the equinoctial points, had been long
known to astronomers; its rate had been measur¬
ed by a comparison of ancient and modern ob¬
servations, and found to amount nearly to 50"
annually, so as to complete an entire revolution
of the heavens in 25,920 years. Nothing seem¬
ed more difficult to explain than this phenome¬
non, and no idea of assigning a physical or me¬
chanical cause for it had yet occurred, I believe,
to the boldest and most theoretical astronomer.
The honour of assigning the true cause was re¬
served for the most cautious of philosophers.
He was directed to this by a certain analogy ob¬
served between the precession of the equinoxes
and the retrogradation of the moon’s nodes, a
phenomenon to which his calculus had been
already successfully applied. The spheroidal
shell or ring of matter which surrounds the
earth, as we have just seen, in the direction of
the equator, being one half above the plane of
the ecliptic and the other half below, is subject¬
ed to the action of the solar force, the tendency
of which is to make this ring turn on the line of
its intersection with the ecliptic, so as ultimate¬
ly to coincide with the plane of that circle.
This, accordingly, would have happened long
since, if the earth had not revolved on its axis.
The effect of the rotation of the spheroidal ring
from west to east, at the same time that it is
drawn down toward the plane of the ecliptic,
is to preserve the inclination of these two planes
unchanged, but to make their intersection move
in a direction opposite to that of the diurnal ro¬
tation, that is, from east to west, or contrary to
the order of the signs.
The calculus in its result justified this general
conclusion : 10" appeared the part of the effect
due to the moon’s attraction, 40" to the attrac¬
tion of the sun; and I know not if there he any
thing respecting the constitution of our system,
in which this great philosopher gave a stronger
proof of his sagacity and penetration, than in
the explanation of this phenomenon. The truth,
however, is, that his data for resolving the pro¬
blem were in some degree imperfect, all the cir¬
cumstances were not included, and some were
erroneously applied, yet the great principle and
scope of the solution were right, and the ap¬
proximation very near to the truth. “ II a ete
bien servi par son genie,” says the eloquent and
judicious historian of astronomy; “ I’inspira-
tion de cette faculte divine lui a fait appercevoir
des determinations qui n’etoient pas encore
accessibles; soit qu’il eut des preuves qu’il a
supprimees, soit qulil eut dans Vesprit une sorte
tfestime, une espece de balance pour apprecier cer-
taines verites, enpesant les verites prochaines, et
jugeant les unes par les autres”*
It Avas reserved for a more advanced condi¬
tion of the new analysis to give to the solution
of this problem all the accuracy of which it is
susceptible. It is a part, and a distinguishing
part, of the glory of this system, that it Avas sus¬
ceptible of more perfection than it received from
the hands of the author; and that the century
and a half which has nearly elapsed since the
first discovery of it has been continually adding
to its perfection. This character belongs to a
system which has truth and nature for its basis,
and had not been exhibited in any of the phy¬
sical theories that had yet appeared in the world.
1 Princip. lib. iii. prop. 20.
* Bailly, Histone de VAstronomic Moderne, tome II. livre xii. sect. 28.
DISSERTATION FOURTH.
679
The doctrines of Plato and Aristotle were
never more perfect than when they came from
the hands of their respective authors ; and a le¬
gion of commentators, with all their efforts, did
nothing but run round perpetually in the same
circle. Even Descartes, though he had recourse
to physical principles, and tried to fix his sys¬
tem on a firmer basis than the mere abstractions
of the mind, left behind him a work which not
only could not be improved, but was such, that
every addition attempted to be made destroyed
the equilibrium of the mass, and pulled away
the part to which it was intended that it should
be attached. The philosophy of Newton has
proved susceptible of continual improvement;
its theories have explained facts quite unknown
to the author of it; and the exertions of La¬
grange and Laplace, at the distance of a hun¬
dred years, have perfected a work which it was
not for any of the human race to begin and to
complete.
Newton next turned his attention to the phe¬
nomena of the Tides, the dependence of which
on the moon, and in part also on the sun, was
sufficiently obvious even from common observa¬
tion. That the moon is the prime ruler of the
tide, is evident from the fact, that the high-
water, at any given place, occurs always nearly
at the moment when the moon is on the same
meridian, and that the retardation of the tide
from day to day is the same with the retarda¬
tion of the moon in her diurnal revolution. That
the sun is also concerned in the production of
the tides is evident from this, that the highest
tides happen when the sun, the moon, and the
earth are all three in the same straight line;
and that the lowest, or neap tides, happen when
the lines drawn from the sun and moon to the
earth make right angles with one another. The
eye of Newton, accustomed to generalize and to
penetrate beyond the surface of things, saw that
the waters of the sea revolving with the earth
are nearly in the condition of a satellite revolv¬
ing about its primary, and are liable to the
same kind of disturbance from the attraction of
a third body. The fact in the history of the
tides which seems most difficult to be explained,
received, on this supposition, a very easy solu¬
tion. It is known that high-water always takes
place in the hemisphere where the moon is, and
in the opposite hemisphere where the moon is
not, nearly at the same time. This seems, at
first sight, very unlike an effect of the moon’s
attraction; for, though the water in the hemi¬
sphere where the moon is, and which therefore
is nearest the moon, may be drawn up toward
that body, the same ought not to happen in the
opposite hemisphere, where the earth’s surface
is most distant from the moon. But if the ac¬
tion of the moon disturb the equilibrium of the
ocean, just as the action of one planet disturbs
the motion of a satellite moving round another,
it is exactly what might be expected. It had
been shown that the moon, in conjunction with
the sun, has her gravitation to the earth dimi¬
nished, and when in opposition to the sun has it
dimihishyd very nearly by the same quantity.
The reason is, that at the conjunction, or the new
moon, the moon is drawn to the sun more than
the earth is; and that, at the opposition, or full
moon, the earth is drawn toward the sun more
than the moon nearly by the same quantity: the
relative motion of the two bodies is therefore
affected the same way in both cases, and the
gravity of the moon to the earth, or her ten¬
dency to descend toward it, is in both cases less¬
ened.
It is plain that the action of the moon on the
waters of the ocean must be regulated by the
same principle. In the hemisphere where the
moon is, the water is more drawn toward the
moon than the mass of the earth is, and its gra¬
vity being lessened, the columns toward the
middle of the hemisphere lengthen, in conse¬
quence of the pressure of the columns which are
at a distance from the middle point, of which
the weight is less diminished, and toward the
horizon must even be increased. In the oppo¬
site hemisphere, again, the mass of the earth is
more drawn to the moon than the waters of that
hemisphere, and their relative tendencies are
changed in the same direction, and nearly by the
same quantity. If the action of the moon on
all the parts of the earth, both sea and land,
were the same, no tide whatever would be pro¬
duced.
Thus, the same analysis of the force of gravi¬
ty which explained the inequalities of the moon.
680
PRELIMINARY DISSERTATIONS.
were shown by Newton to explain those ine¬
qualities in the elevation of the waters of the
ocean to which we give the name of tides. On
the principle also explained in this analysis
it is that the attraction of the sun and moon
conspire to elevate the waters of the ocean, whe¬
ther these luminaries be in opposition or con¬
junction. In both cases the solar and lunar tides
are added together, and the tide actually observ¬
ed is their sum. At the quadratures, or the first
and third quarters, these two sides are opposed
to one another, the high water of the lunar tide
coinciding with the low water of the solar, and
conversely, so that the tide actually observed is
the difference of the two.
The other phenomena of the tides were ex¬
plained in a manner no less satisfactory; and it
only remained to inquire, whether the quantity
of the solar and lunar forces were adequate to
the effect thus ascribed to them. The lunar
force there were yet no data for measuring; but
a measure of the solar force, as it acts on the
moon, had been obtained, and it had been shown
that in its mean quantity it amounted to of
the force which retains the moon in her orbit.
This last is ^555 of the force of gravity at the
earth’s surface; and, therefore, the force with
which the sun disturbs the moon’s motion is
its X of gravity at the earth’s surface.
This is the solar disturbing force on the moon
when distant sixty semidiameters from the
earth’s centre; but on a body only one semidia¬
meter distant from that centre, that is, on the
water of the ocean, the disturbing force would
be sixty times less, and thus is found to be no
more than jS54V550 of gravity at the earth’s
surface.
Now, this being the mean force of the sun,
is that by which he acts on the waters, 90 de¬
grees distant from the point to which he is ver¬
tical, where it is added to the force of gravity,
and tends to increase the weight and lower the
level of the waters. At the point where the
sun is vertical, the force to raise the water is
about double of this ; and, therefore, the whole
force tending to raise the level of the high
above that of the low water is three times the
preceding, or about the t^iVooo of gravity.
Small as this force is, when it is applied to
every particle of the ocean, it is capable of pro¬
ducing a sensible effect. The manner in which
Newton estimates this effect can only be con¬
sidered as affording an approximation to the
truth. In treating of the figure of the earth,
he had shown that the centrifugal force, amount¬
ing to jig of gravity, was able to raise the
level of the ocean more than seventeen miles,
or, more exactly, 85,472 French feet. Hence,
making the effect proportional to the forces, the
elevation of the waters produced by the solar
force will come out 1*92 foot.
But, from the comparison of the neap and
spring tides, that is, of the difference and the
sum of the lunar and solar forces, it appears
that the force of the moon is to that of the sun
as 4*48 to 1. As the solar force raises the tide
1’92 foot, the lunar will raise it 8’63 feet; so
that the two together will produce a tide of 10^
French feet,1 which agrees not ill with what is
observed in the open sea, at a distance from
land.
The calculus of Newton stopped not here.
From the force that the moon exerts on the
waters of the ocean, he found the quantity of
matter in the moon to that in the earth as 1 to
39-78, or, in round numbers, as 1 to 40. He
also found the density of the moon to the den¬
sity of the earth as 11 to 9.
Subsequent investigations, as we shall have
occasion to remark, have shown that much was
yet wanting to a complete theory of the tides;
and that even after Maclaurin, Bernoulli, and
Euler2 had added their efforts to those of New¬
ton, there remained enough to give full employ¬
ment to the calculus of Laplace. As an ori¬
ginal deduction, and as a first approximation,
that of which I have now given an account
will be for ever memorable.
The motion of Comets yet remained to be
discussed. They had only lately been acknow-
1 Newtoxi Princip. lib. iii. prop. 36, 37.
2 See the solutions ol these three mathematicians in the Commentary of'Le Seur and Jacquier on the third book of the
Principia.
DISSERTATION FOURTH.
681
ledged to belong to the heavens, and to be
placed beyond the region of the earth’s atmo¬
sphere ; but with regard to their motion, astro¬
nomers were not agreed. Kepler believed them
to move in straight lines; Cassini thought they
moved in the planes of great circles, but with
little curvature. Hevelius had come much
nearer the truth: he had shown the curvature
of their paths to be different in different parts,
and to be greatest when they were nearest
the sun; and a parabola having its vertex in
that point seemed to him to be the line in
which the comet moved. Newton, convinced
of the universality of the principle of gra¬
vitation, had no doubt that the orbit of the
comet must be a conic section, having the sun
in one of its foci, and might either be an ellipse,
a parabola, or even an hyperbola, according to
the relation between the force of projection and
the force tending to the centre. As the eccen¬
tricity of the orbit on every supposition must be
great, the portion of it that fell within our view
could not differ much from a parabola; a cir¬
cumstance which rendered the calculation of the
comet’s place, when the position of the orbit
was once ascertained, more easy than in the case
of the planets. Thus far theory proceeded; and
observation must then determine with what de¬
gree of accuracy this theory represented the
phenomena. From three observations of the
comet the position of the orbit could be deter¬
mined, though the geometric problem was one
of great difficulty. Newton gave a solution of
it; and it was by this that his theory was to be
brought to the test of experiment. If the orbit
thus determined was not the true one, the places
of the comet calculated on the supposition that
it was, and that it described equal areas in equal
times about the sun, could not agree with the
places actually observed. Newton showed, by
the example of the remarkable comet then vi¬
sible, (1680) that this agreement was as great
as could reasonably be expected; thus adding
another proof to the number of those already
brought to support the principle of universal
gravitation. The comets descend into our sys¬
tem from all different quarters in the heavens,
and therefore the proofs that they afforded went
to show, that the action of gravity was confined
to no particular region of the heavens.
Thus far Newton proceeded in ascertaining
the existence, and in tracing the effects, of the
principle of gravitation, and had done so with a
success of which there had been no instance in
the history of human knowledge. At the same
time that it was the most successful, it was the
most difficult research that had yet been under¬
taken. The reasonings upward from the facts
to the general principle, and again down from
that principle to its effects, both required the
application of a mathematical analysis which
was but newly invented; and Newton had not
only the difficulties of the investigation to en¬
counter, but the instrument to invent, without
which the investigation could not have been
conducted. Every one who considers all this
will readily join in the sentiment with which
Bailly closes a eulogy as just as it is eloquent:
“ Si, comme Platon Fa pense, il existoit dans la na¬
ture une bchelle d’etres et de substances intelligentes
jusqu’a VEtre Supreme, Vespece humaine, de¬
fendant ses droits, auroit une foule de grands
hommes d presenter ; mais Newton, suim de ses
verites pures, montreroit le plus haut degre de
force de Vesprit humain, et svffiroit seul pour lui
assignor sa vraie place.”1
Though the creative power of genius was never
more clearly evinced than in the discoveries of
this great philosopher, yet the influence of cir¬
cumstances, always extensive and irresistible in
human affairs, can readily be traced. The con¬
dition of knowledge at the time when Newton
appeared was favourable to great exertions; it
was a moment when things might be said to be
prepared for a revolution in the mathematical
and physical sciences. The genius of Copernicus
had unfolded the true system of the world; and
Galileo had shown its excellence, and established
it by arguments, the force of which were gene¬
rally acknowledged. Kepler had done still more,
having, by an admirable effort of generalization,
reduced the facts concerning the planetary mo¬
tions to three general laws. Cassini’s observa¬
tions had also extended the third of these laws
1 Histoire de VAstronomic Moderne, tome II. livre xii. sect. 49.
DISS. IV., PART II.
4 R
682
PRELIMINARY DISSERTATIONS.
to the satellites of Jupiter, showing that the
squares of their periodic times were as the cubes
of their distances from the centre of the body
round which they revolved. T. he imaginary ap¬
paratus of cycles and epicycles, the immobility
of the earth,—the supposed essential distinction
between celestial and terrestrial substances,
those insuperable obstacles to real knowledge,
which the prejudice of the ancients had establish¬
ed as physical truths, were entirely removed;
and Bacon had taught the true laws of philoso¬
phizing, and pointed out the genuine method of
extracting knowledge from experiment and ob¬
servation. The leading principles of mechanics
were established; and it was no unimportant
circumstance, that the Vortices of Descartes had
exhausted one of the sources of error, most se¬
ducing on account of its simplicity.
All this had been done when the genius of
Newton arose upon the earth. Never till now
had there been set before any of the human race
so brilliant a career to run, or so noble a prize
to he obtained. In the progress of knowledge,
a moment had arrived more favourable to the de¬
velopment of talent than any other, either later
or earlier, and in which it might produce the
greatest possible effect. But, let it not he sup¬
posed, while I thus admit the influence of ex¬
ternal circumstances on the exertions of intellec¬
tual power, that I am lessening the merit of this
last, or taking any thing from the admiration
that is due to it. I am, in truth, only distin¬
guishing between what it is possible and what
it is impossible for the human mind to effect.
With ail the aid that circumstances could give,
it required the highest degree of intellectual
power to accomplish what Newton performed.
We have here a memorable, perhaps a singu¬
lar instance, of the highest degree of intellec¬
tual power, united to the most favourable con¬
dition of things for its exertion. Though New¬
ton’s situation was more favourable than that
of the men of science who had gone before
him, it was not more so than that of those men
who pursued the same objects at the same time
with himself, placed in a situation equally fa¬
vourable.
When one considers the splendour of New¬
ton’s discoveries, the beauty, the simplicity, and
grandeur of the system they unfolded, and the
demonstrative evidence by which that system
was supported, one could hardly doubt that, to
he received, it required only to he made known,
and that the establishment of the Newtonian
philosophy all over Europe would very quickly
have followed the publication of it. In drawing
this conclusion, however, we should make much
too small an allowance for the influence of re¬
ceived opinion, and the resistance that mere ha¬
bit is able, for a time, to oppose to the strongest
evidence. The Cartesian system of vortices had
many followers in all the countries of Europe,
and particularly in France. In the universities
of England, though the Aristotelian Physics had
made an obstinate resistance, they had been sup¬
planted by the Cartesian, which became firmly
established about the time when their founda¬
tion began to he sapped by the general progress
of science, and particularly by the discoveries
of Newton. For more than thirty years after
the publication of those discoveries, the system
of vortices kept its ground; and a translation
from the French into Latin of the Physios of
Rohault, a work entirely Cartesian, continued
at Cambridge to he the text for philosophical in¬
struction. About the year 1718, a new and
more elegant translation of the same book was
published by Dr Samuel Clarke, with the addi¬
tion of notes, in which that profound and inge¬
nious writer explained the views of Newton on
the principal objects of discussion; so that the
notes contained virtually a refutation of the text:
they did so, however, only virtually, all appear¬
ance of argument and controversy being care¬
fully avoided. Whether this escaped the notice
of the learned Doctors or not, is uncertain; hut
the new translation, from its better Latinity,
and the name of the editor, was readily admit¬
ted to all the academical honours which the old
one had enjoyed. Thus, the stratagem of Dr
Clarke completely succeeded; the tutor might
prelect from the text, hut the pupil would some¬
times look into the notes; and error is never so
sure of being exposed as when the truth is placed
close to it, side by side, without any thing to
alarm prejudice, or awaken from its lethargy
the dread of innovation. Thus, therefore, the
Newtonian philosophy first entered the Univer-
DISSERTATION FOURTH.
683
sity of Cambridge under the protection of the
Cartesian.1
If such were the obstacles to its progress that
the new philosophy experienced in a country
that was proud of having given birth to its
author, we must expect it to advance very slow¬
ly indeed among foreign nations. In France,
we find the first astronomers and mathemati¬
cians, such men as Cassini and Maraldi, quite un¬
acquainted with it, and employed in calculating
the paths of the comets they w'ere observing, on
hypotheses the most unfounded and imaginary;
long after Halley, following the principles of
Newton, had computed tables from which the
motions of all the comets that ever had appear¬
ed, or ever could appear, might be easily deduc¬
ed. Fontenelle, with great talents and enlarged
views, and, as one may say, officially informed
of the progress of science all over Europe, con¬
tinued a Cartesian to the end of his days.
Mairan in his youth was a zealous defender of
the vortices, though he became afterwards one
of the most strenuous supporters of the doctrine
of gravitation.
A Memoir of the Chevalier Louville, among
those of the Academy of Sciences for 1720, is
the first in that collection, and, I believe, the
first published in France, where the elliptic mo¬
tion of the planets is supposed to he produced by
the combination of two forces, one projectile and
the other centripetal. Maupertuis soon after
went much farther : in his elegant and philoso¬
phic treatise, Figure des Astres, published about
1730, he not only admitted the existence of at¬
traction as a fact, but even defended it, when
considered as an universal property of body,
against the reproach of being a metaphysical ab¬
surdity. These were considerable advances, but
they were made slowly; and it was true, as Vol¬
taire afterwards remarked, that though the au¬
thor of the Principia survived the publication
of that great work nearly forty years, he had
not, at the time of his death, twenty followers
out of England.
We should do wrong, however, to attribute
this slow conversion of the philosophic world
entirely to prejudice, inertness, or apathy. The
evidence of the Newtonian philosophy was of a
nature to require time in order to make an im¬
pression. It implied an application of mathe¬
matical reasoning which was often difficult: the
doctrine of prime and ultimate ratios was new
to most readers, and could be familiar only to
those who had studied the infinitesimal analysis.
The principle of gravitation itself was con¬
sidered as difficult to be admitted. When pre¬
sented indeed as a mere fact, like the weight of
bodies at the earth’s surface, or their tendency
to fall to the ground, it was free from objection;
and it was in this light only that Newton wish¬
ed it to be considered.2 But though this appears
to be the sound and philosophical view of the
subject, there has always appeared a strong de¬
sire in those who speculated concerning gravita¬
tion to go farther, and to inquire into the cause
of what, as a mere fact, they were sufficiently
disposed to admit. If you said that you had no
explanation to give, and were only desirous of
having the fact admitted, they alleged that
this was an unsatisfactory proceeding,—that it
was admitting the doctrine of occult causes,—that
it amounted to the assertion, that bodies acted
in places where they were not,—a proposition
that, metaphysically considered, was undoubted-
Th^ U"lveiT.ties Andrews and Edinburgh were, I believe, the first in Britain where the Newtonian nhilosonhi
was made the subject of the academical prelections. For this distinction they are indebted to James and David Gregory
the first in some respects the rival, but both the friends of Newton. Whiston bewails in the anguish of his heart the dif
ference in this respect between those universities and his own. David Gregory taught in Edinburgh for several year
prior to 1690 when he removed to Oxford ; and Whiston says, “ He had already caused several of his scholars to ^e
acts, as we call them, upon several branches of the Newtonian philosophy, while we at Cambridge (poor wretches) were J
nomimousiy studying the fictitious hypotheses of the Cartesian.” (Whiston’s Memoirs of his own Life.) I do not how
hlfdt ?eari rn8*7’ that fr0m thls d*te the Cartesian Philosophy was expelled from those universities. The PwLofRo
hault were still in use as a text, at least occasionally, to a much later period than this; and a great deal no doubt denend
ed on the character of the individual professors. Keill introduced the Newtonian philosophyfn hi ScCs at Oxforrfii
1697, but the instructions of the tutors, which constitute the real and efficient system of the university were not cast in
p™s that the
prop. 69.) F onatur, corpora mnatanha m se mvicem utcunque impellentis." {Principia Math. lib. i. schol. ad finem
684
PRELIMINARY DISSERTATIONS.
ly absurd. The desire to explain gravitation is
indeed so natural, that Newton himself felt its
force, and has thrown out, at the end of his
Optics, some curious conjectures concerning this
general affection of body, and the nature of that
elastic ether to which he thought that it was
perhaps to he ascribed. “ Is not this medium
(the ether) much rarer within the dense bodies
of the sun, stars, and planets, than in the empty
celestial spaces between them ? And, in passing
from them to great distances, does it not grow
denser and denser perpetually, and thereby cause
the gravity of those great bodies to one another,
every body endeavouring to go from the denser
parts of the medium to the rarer P”1
Notwithstanding the highest respect for the
author of these conjectures, I cannot find any
thing like a satisfactory explanation of gravity
in the existence of this elastic ether. It is very
true that an elastic fluid, of which the density
followed the inverse ratio of the distance from a
given point, would urge the bodies immersed in
it, and impervious to it, toward that point with
forces inversely as the squares of the distances
from it; but what could maintain an elastic
fluid in this condition, or with its density vary¬
ing according to this law, is a thing as inexpli¬
cable as the gravity which it was meant to ex¬
plain. The nature of an elastic fluid must be,
in the absence of all inequality of pressure, to
become everywhere of the same density. If the
causes that produce so marked and so general a
deviation from this rule be not assigned, we can
only be said to have substituted one difficulty for
another.
A different view of the matter was taken by
some of tbe disciples and friends of Newton,
but which certainly did not lead to any thing
more satisfactory. That philosopher himself
had always expressed his decided opinion that
gravity could not be considered as a property
of matter;2 but Mr Cotes, in the preface to
the second edition of the Principia, maintains
that gravity is a property which we have the
same right to ascribe to matter, that we have to
ascribe to it extension, impenetrability, or any
other property. This is said to have been in¬
serted without the knowledge of Newton,—a
freedom which it is difficult to conceive that any
man could use with the author of the Principia.
However that be, it is certain that these diffi¬
culties have been always felt, and had their
share in retarding the progress of the philosophy
to which they seemed to be inseparably attached.
There were other arguments of a less abstruse
nature, and more immediately connected with
experiment, which, for a time, resisted the pro¬
gress of the Newtonian philosophy, though they
contributed, in tbe end, very materially to its
advancement. Nothing, indeed, is so hostile to
the interests of truth, as facts inaccurately ob¬
served ; of which we have a remarkable example
in the measurement of an arch of the meridian
across France, from Amiens to Perpignan,
though so large as to comprehend about seven
degrees, and though executed by Cassini, one of
the first astronomers in Europe. According to
that measurement, the degrees seemed to dimi¬
nish on going from south to north, each being
less by about an 800th part than that which im¬
mediately preceded it toward the south. From
this result, which is entirely erroneous, the con¬
clusion first deduced was correct, the error in
the reasoning, by a very singular coincidence,
1 Optics, query 21, at the end of the third book. . # . rp,
2 The passages quoted sufficiently prove that Newton did not consider gravity as a property inherent in mat er* e
following passage in one of his letters to Dr Bentley is still more explicit: u It is inconceivable that inanimate ru e
matter should, without the mediation of something else, which is not material, operate upon and afreet other matter wi i-
out mutual contact; as it must do, if gravitation, in the sense of Epicurus, be essential and inherent in it... I hat gravi y
should be innate, inherent, and essential to matter, so that one body may act upon another at a distance through a vacuum,
without the mediation of any thing else, by and through which their action and force may be conveyed from one to another,
is to me so great an absurdity, that I believe no man who has in philosophical matters a competent faculty of thinking
can ever fall into it.” (Newtoni Opera, tom. IV. p. 438. Horsley’s edit.) On this passage I cannot help remarking, that it
is not quite clear in what manner the interposition of a material substance can convey the action of distant bodies to one
another. In the case of percussion or pressure, this is indeed very intelligible, but it is by no means so m the case of at¬
traction. If two particles of matter, at opposite extremities of the diameter of the earth, attract one another, this effect is
just as little intelligible, and the modus agendi is just as mysterious, on the supposition that the whole globe of the earth is
interposed, as on that of nothing whatever being interposed, or of a complete vacuum existing between them. It is not
enough that each particle attracts that in contact with it; it must attract the particles that are distant, and the interven¬
tion of particles between them does ndt rerider this at ail more intelligible.
DISSERTATION FOURTH.
685
having corrected the error in the data from
which it was deduced. Fontenelle argued that,
as the degrees diminished in length on going
toward the poles, the meridian must he less than
the circumference of the equator, and the earth
of course swelled out in the plane of that circle,
agreeably to the facts that had been observed
concerning the retardation of the pendulum
when carried to the south. This, however,
was the direct contrary of the conclusion which
ought to have been drawn, as was soon per¬
ceived by Cassini and by Fontenelle himself.
The degrees growing less as they approached
the pole, was an indication of the curvature
growing greater, or of the longer axis of the
meridian being the line that passed through the
poles, and that coincided with the axis of the
earth. The figure of the earth must, therefore,
be that of an oblong spheroid, or one formed by
the revolution of an ellipsis about its longer
axis. This conclusion seemed to be strengthened
by the prolongation of the meridian from Amiens
northward to Dunkirk in 1713, as the same di¬
minution was observed; the medium length of
the degree between Paris and Dunkirk being
56970 toises, no less than 137 less than the mean
of the degrees toward the south.1 All this
seemed quite inconsistent with the observations
on the pendulum, as well as with the conclusions
which Newton had deduced from the theory of
gravity. The Academy of Sciences was thus
greatly perplexed, and uncertain to what side
to incline. In these circumstances, J. Cassini,
whose errors were the cause of all the difficulty,
had the merit of suggesting the only means by
which the question concerning the figure of the
earth was likely to receive a satisfactory solu¬
tion,—the measurement of two degrees, the one
under the equator, and the other as near to the
pole as the nature of the thing would admit.
But it was not till considerably beyond the
limits of the period of which I am now treat¬
ing, that these measures were executed, and
that the increase of the degrees toward the
poles, or the oblateness of the earth’s figure,
was completely ascertained. Cassini, on resum¬
ing his own operations, discovered, and candid¬
ly acknowledged, the errors in his first mea¬
surement; and thus the objections which had
arisen in this quarter against the theory of gra¬
vity became irresistible arguments in its favour.
This subject will occupy much of our attention
in the history of the second period, till which
the establishment of the Newtonian philosophy
on the Continent cannot be said to have been
accomplished.
In addition to these discoveries in physical
astronomy, this period affords several on the
descriptive parts of the science, of which, how¬
ever, I can only mention one, as far too impor¬
tant to be passed over in the most general out¬
line. It regards the apparent motion in the
fixed stars, known by the name of the Aberra¬
tion, and is the discovery of Dr Bradley, one of
the most distinguished astronomers of whom
England has to boast. Bradley and his friend
Molyneux, in the end of the year i725,a were
occupied in searching for the parallax of the
fixed stars by means of a zenith sector, con¬
structed by Graham, the most skilful instru¬
ment maker of that period. The sector was
erected at Kew; it was of great radius, and
furnished with a telescope twenty-four feet in
length, with which they proposed to observe
the transits of stars near the zenith, according
to a method that was first suggested by Hooke,
and pursued by him so far as to induce him to
think that he had actually discovered the paral¬
lax of y Draconis, the bright star in the head of
the dragon, on which he made his observations.
They began their observations of the transits of
the same star on the 3d of December, when the
distance from the zenith at which it passed was
carefully marked. By the observations of the
subsequent days the star seemed to be moving
to the south; and about the beginning of March
in the following year, it had got 20" to the
south, and was then nearly stationary. In the
beginning of June it had come back to the same
situation where it was first observed, and from
thence it continued its motion northward till
September, when it was about 20" north of the
point where it was first seen, its whole change
of declination having amounted to 40".
1 Mtmoires de VAcadtmie des Sciences, 1718, P- 245.
2 Phil. Trans, vol. XXXY. p. 697»
686
PRELIMINARY DISSERTATIONS.
This motion occasioned a good deal of sur¬
prise to the two observers, as it lay the contrary
way to what it would have done if it had pro¬
ceeded from the parallax of the star. The re¬
petition of the observations, however, confiimed
their accuracy; and they were afterwards pur¬
sued by Dr Bradley, with another sector con¬
structed also by Graham, of a less radius, but
still of one sufficiently great to measure a star’s
zenith distance to half a second. It embraced a
larger arch, and admitted of the observations
being extended to stars that passed at a more
considerable distance from the zenith.
Even with this addition the observations did
not put Bradley in possession of the complete
fact, as they only gave the motion of each star
in declination, without giving information about
what change might be produced in its right as¬
cension.
Had the whole fact, that is, the motion in
right ascension as well as in declination, been
given from observation, it could not have been
long before the cause was discovered. With
such information, however, as Dr Bradley had,
that discovery is certainly to be regarded as a
great effort of sagacity. He has not told us the
steps by which he was led to it; only we see
that, by the method of exclusion, he had been
careful to narrow the field of hypothesis, and
had assured himself that the phenomenon was
not produced by any nutation of the earth’s
axis,—by any change in the direction of the
plumb-line, or by refraction of any kind. All
these causes being rejected, it occurred to him
that the appearances might arise from the pro¬
gressive motion of light combined with the mo¬
tion of the earth in its orbit. He reasoned some¬
what in this manner. If the earth were at rest,
it is plain that a telescope, to admit a ray of
light coming from a star to pass along its axis,
must be directed to the star itself. But, if the
earth, and of course the telescope, be in motion,
it must be inclined forward, so as to be in the
diagonal of a parallelogram, the sides of which
represent the motion of the earth and the mo¬
tion of light; or in the direction of those mo¬
tions, and in the ratio of their velocities. It is
with the telescope just as with the vane at the
mast-head of a ship: when the ship is at anchor,
the vane takes exactly the direction of the wind ;
when the ship is under weigh, it places itself in
the diagonal of a parallelogram, of which one
side represents the velocity of the ship, and the
other the velocity of the wind. If, instead of
the vane, we conceive a hollow tube, movable
in the same manner, the case will become more
exactly parallel to that of the telescope. The
tube will take such a position that the wind
may blow through it without striking against the
sides, and its axis will then be the diagonal of
the parallelogram just referred to.
The telescope, therefore, through which a star
is viewed, and by the axis of which its position
star is determined, must make an angle with the
straight line drawn to the star, except when the
earth moves directly upon the star, or directly
from it. Hence it follows, that if the star be
in the pole of the ecliptic, the telescope must be
pointed forward, in the direction of the earth’s
motion, always by the same angle; so that the
star would be seen out of its true place by that
angle, and would appear to describe a circle
round the pole of the ecliptic, the radius of
which subtended, at the earth, an angle, of
which the sine is to unity as the velocity of the
earth to the velocity of light. If the star be
anywhere between the plane of the ecliptic and
the pole, its apparent path will be an ellipse,
the longer axis of which is the same with the
diameter of the former circle, and the shorter
equal to the same quantity, multiplied by the
sine of the star’s latitude. If the star be in
the plane of the ecliptic, this shorter axis
vanishes, and the apparent path of the star
is a straight line, equal to the axis just men¬
tioned.
Bradley saw that Roemer’s observation con¬
cerning the time that light takes to go from the
sun to the earth gave a ready expression for the
velocity of light compared with that of the
earth. The proportion, however, which he as¬
sumed as best suited to his observations was
somewhat different; it was that of 10313 to 1,
which made the radius of the circle of aberra¬
tion 20", and the transverse axis of the ellipse
in every case, or the whole change of position,
40". It was the shorter axis which Bradley
had actually observed in the case of y Draconis,
DISSERTATION FOURTH.
687
that star being very near the solstitial colure,
so that its changes of declination and of latitude
are almost the same. In order to show the
truth of his theory, he computed the aberration
of different stars, and, on comparing the results
with his observations, the coincidence appeared
almost perfect, so that no doubt remained con¬
cerning the truth of the principle on which he
had founded his calculations. He did not ex¬
plain the rules themselves: Clairaut published
the first investigation of these in the Memoirs
of the Academy of Sciences for 1737. Simpson
also gave a demonstration of them in his Essays,
published in 1740.
It has been remarked, that the velocity of
light, as assumed by Bradley, did not exactly
agree with that which Roemer had assigned:
supposing the total amount of the aberration
40^", it gave the time that light takes to come
from the sun to the earth S' 13"; but it is pro¬
per to add, that since the time of this astrono¬
mer, the velocity of light deduced from the
eclipses of Jupiter’s satellites has been found
exactly the same.
It is remarkable that the phenomenon thus
discovered by Bradley and Molyneux, when in
search of the parallax of the fixed stars, is in
reality as convincing a proof of the earth’s mo¬
tion in its orbit as the discovery of that paral¬
lax would have been. It seems, indeed, as sa¬
tisfactory as any evidence that can be desired.
One only regrets, in reflecting on this discovery,
that the phenomenon of the aberration was not
foreseen, and that, after being predicted from
theory, it had been ascertained from observa¬
tion. As the matter stands, however, the dis¬
covery both of the fact and the theory is highly
creditable to its author.
In the imperfect outline which I have now
sketched of one of the most interesting periods
in the history of human knowledge, much has
been omitted, and many great characters passed
over, lost, as it were, in the splendour of the
two great luminaries which marked this epocha.
Newton and Leibnitz are so distinguished from
the rest even of the scientific world, that we can
only compare them with one another, though,
in fact, no two intellectual characters, who both
reached the highest degree of excellence, were
ever more dissimilar.
For the variety of his genius, and the extent
of his research, Leibnitz is perhaps altogether
unrivalled. A lawyer, an historian, an antiquary,
a poet, and a philologist,—a mathematician, a
metaphysician, a theologian, and, I will add, a
geologer, he has in all these characters produced
works of great merit, and in some of them of
the highest excellence. It is rare that original
genius has so little of a peculiar direction, or is
disposed to scatter its efforts over so wide a field.
Though a man of great inventive powers, he oc¬
cupied much of his time in works of mere labour
and erudition, where there was nothing to in¬
vent, and not much of importance to discover.
Of his inventive powers as a mathematician we
have already spoken; as a metaphysician, his
acuteness and depth are universally admitted:
but metaphysics is a science in which there are
few discoveries to be made; and the man who
searches in it for novelty, is more likely to find
what is imaginary than what is real. The no¬
tion of the Monads, those un extended units, or
simple essences, of which, according to this phi¬
losopher, all things corporeal and spiritual, ma¬
terial or intellectual, are formed, will be readily
allowed to have more in it of novelty than truth.
The pre-established harmony between the body
and the mind, by which two substances inca¬
pable of acting on one another are so nicely ad-
j usted from the beginning, that their movements
for ever correspond, is a system of which no ar¬
gument can do more than prove the possibility.
And, amid all the talent and acuteness with
which these doctrines are supported, it seems to
argue some unsoundness of understanding, to have
thought that they could ever find a place among
the established principles of human knowledge.
Newton did not aim at so wide a range. For¬
tunately for himself and for the world, his ge¬
nius was more determined to a particular point,
and its efforts were more concentrated. Their
direction was to the accurate sciences, and they
688
PRELIMINARY DISSERTATIONS.
soon proved equally inventive in the pure and
in the mixed mathematics. Newton knew how
to transfer the truths of abstract science to the
study of things actually existing, and, by return¬
ing in the opposite direction, to enrich the foi -
mer by ideas derived from the latter. In expe¬
rimental and inductive investigation he was as
great as in the pure mathematics, and his disco¬
veries as distinguished in the one as in the other.
In this double claim to renown, Newton stands
yet unrivalled; and though, in the pure mathe¬
matics, equals may perhaps be found, no one, I
believe, will come forward as his rival both in
that science and in the philosophy of nature.
His caution in adopting general principles, his
dislike to what was vague or obscure, his re¬
jection of all theories from which precise conclu¬
sions cannot be deduced, and his readiness to
relinquish those that depart in any degree from
the truth, are, throughout, the characters of his
philosophy, and distinguish it very essentially
from the philosophy of Leibnitz. The characters
now enumerated are most of them negative ; but
without the principles on which they are founded,
invention can hardly be kept in the right course.
The German philosopher was not furnished with
them in the same degree as the English, and
hence his great talents have run very frequently
to waste.
It may be doubted also, whether Leibnitz’s
great metaphysical acuteness did not sometimes
mislead him in the study of nature, by inclining
him to those reasonings which proceed, or aifect
to proceed, continually from the cause to the
effect. The attributes of the Deity were the
axioms of his philosophy; and he did not reflect
that this foundation, excellent in itself, lies much
too deep for a structure that is to be raised by
so feeble an architect as man; or, that an argu¬
ment, which sets out with the most profound
respect to the Supreme Being, usually termi¬
nates in the most unwarrantable presumption.
His reasonings from first causes are always in¬
genious; but nothing can prevent the substitu¬
tion of such causes for those that are physical
and efficient, from being one of the worst and
most fatal errors in philosophy.
As an interpreter of nature, therefore, Leibnitz
stands in no comparison with Newton. His
general views in physics were vague and unsatis¬
factory; he had no great value for inductive
reasoning; it was not the way of arriving at
truth which he was accustomed to take; and
hence, to the greatest physical discovery of that
age, and that which was established by the most
ample induction, the existence of gravity as a
fact in which all bodies agree, he was always
incredulous, because no proof of it, a 'priori,
could be given.
As to who benefited human knowledge the
most, no question, therefore, can arise; and if
genius is to be weighed in this balance, it is
evident which scale must preponderate. Except
in the pure mathematics, Leibnitz, with all his
talents, made no material or permanent addition
to the sciences. Newton, to equal inventions in
mathematics added the greatest discoveries in the
philosophy of nature; and, in passing through
his hands, Mechanics, Optics, and Astronomy,
were not merely improved, but renovated. No
one ever left knowledge in a state so different
from that in which he found it. Men were in¬
structed not only in new truths, but in new
methods of discovering truth; they were made
acquainted with the great principle which con¬
nects together the most distant regions of space,
as well as the most remote periods of duration ;
and which was to lead to future discoveries, far
beyond what the wisest or most sanguine could
anticipate.
EM) OP THE FOURTH DISSERTATION.
DISSERTATION FIFTH:
EXHIBITING^ A GENERAL VIEW
OF THE
PROGRESS OF MATHEMATICAL AND PHYSICAL SCIENCE,
CHIEFLY
DURING THE EIGHTEENTH CENTURY.
By SIR JOHN LESLIE,
PROFESSOR OF NATURAL PHILOSOPHY IN THE UNIVERSITY OF EDINBURGH ;
CORRESPONDING MEMBER OF THE ROYAL INSTITUTE OF FRANCE.
4 S
DISS. V.
DISSERTATION FIFTH.
INTRODUCTION.
The progress of Mathematical and Physical
Science during the brilliant period which closed
with Newton and Leibnitz, has been treated with
fidelity and sustained interest by the hand of a
master, whose calm judgment weighed impar¬
tially the different claims of discovery, whose
powers of illustration could expand the fine re¬
sults, and whose luminous eloquence was com¬
mensurate with the dignity of the subject. To
resume the Discourse, and continue it through
the course of the eighteenth century, is a task
of increasing difficulty, which would require vi¬
gorous resolution, patient research, and skilful
selection. The materials are ample, indeed, hut
they are likewise multifarious, and often lie scat¬
tered among the countless volumes of the Trans¬
actions of Learned Societies. The picture to
be delineated is not less imposing, and has far
greater extent and variety of outline, while it
exhibits more elaboration in its details.
Scientific discovery had, during this latter
period, continued to advance with accelerated
progression ; and the triumphs of penetrating
ingenuity, if not so transcendant, were equally
conspicuous, more diversified, and were spread
over a much wider surface. Observation was di¬
rected with greater skill and attention, and the
delicate art of experimenting better understood,
and more generally practised. The investiga¬
tion of some intricate phenomena called forth
the resources of a refined calculus; and this new
Geometry, the most powerful instrument ever
wielded by human genius, was then cultivated,
especially on the Continent of Europe, with en¬
thusiastic ardour and astonishing success.
Newton, the glory of our island, had no com¬
petitor save Leibnitz in mathematical invention;
but his sublime discoveries in the highest walks
of science—in Optics and Astronomy—gave him
a pre-eminence far above the most towering ri¬
val. Yet such is the slow progress of innova¬
tion, even among the learned, that, for the
space of nearly half a century, his Theory of
Light was generally slighted, and the system
of Universal Attraction treated as a mere fanci¬
ful hypothesis. The Principia, which crowned
the exertions of the creator of philosophical
science, was admired and imperfectly under-
692
preliminary dissertations.
stood by a few of his countrymen, but had to
undergo the ordeal of a rigorous and sometimes
unfriendly examination by foreigners. Averse
from the bustle and contention of letteis, lie
delighted to pursue his profound researches in
perfect seclusion, and had appeared satisfied
with registering the grand series of discoveries
in that concentrated form which best accorded
with the tone of his mighty intellect. When af¬
terwards persuaded reluctantly to publish those
brief compositions, he could not submit to the
drudgery of retracing his steps, or of expanding
his demonstrations, and bringing them nearer
the reach of his contemporaries. Newton was
nine years in possession of the Method of
Fluxions before Leibnitz struck into a similar
path; nor did he give it to the world till an
equal time more had elapsed. The rapid mind
of the German philosopher had framed his Cal¬
culus with less regard to elegance and strict lo¬
gic, but clothed it in a simpler and more defi¬
nite notation or algorithm, which, from its apt¬
ness to improvement, has in the sequel confer¬
red a decided superiority. The diversified oc¬
cupations of Leibnitz allowed him to work only
at intervals on his great invention ; but he found
most able and zealous coadjutors in the two
Bernoullis, who laboured in promoting the new
calculus with uncommon ingenuity, indefati¬
gable activity, and even a contentious emula¬
tion. The Higher Analysis had by such exer¬
tions already acquired greater extension on the
Continent than the Method of Fluxions at its
first publication in England; and our mathema¬
ticians were hence unprepared to follow many
of the abstruse and abbreviated demonstrations
inserted in the Principia. The Differential and
Integral Calculus having thus made such rapid
advances abroad, continued for a long time af¬
terwards to maintain a preponderating ascend¬
ancy. The marks of the Fluxionary Method,
consisting in mere dots, and therefore not sus¬
ceptible of variation or improvement, sensibly
though indirectly checked the tide of invention
in England ; and perhaps the splendour of New¬
ton’s fame had some influence for a season in
overdazzling the lustre of native talent. As a
parallel instance, it may be remarked that no¬
thing pre-eminent in science was produced by
the French, for half a century after the epoch
of Descartes.
The immediate successors of Newton were
still imperfectly prepared to rise to the sublimi¬
ty of their great master, or to scan the vast su¬
perstructure which his genius had reared. Yet
was more scientific invention displayed by them
than had appeared at any former period in Eng¬
land; and nothing but the comparison with
transcendant powers of intellect could tend to
depress their just merits. By their zealous ef¬
forts the System of the Universe was consolidat¬
ed, and its outworks enlarged. Cotes, who was
snatched away at an early age, discovered the
beautiful theorems of Trinomial Factors, and
multiplied the resources of integration by skil¬
ful applications of Logarithms and Circular Arcs.
Brook Taylor laid the foundation of the Method
of Increments or Finite Differences, solved some
of the most intricate problems in Dynamics;
and in this arduous department he successfully
entered the lists with the celebrated Bernoullis.
De Moivre and Stirling particularly distinguish¬
ed themselves, by extending and applying the
Doctrine of Series, a most important branch of
the Fluxionary Calculus. In the great astro¬
nomical discoveries, England still led the way.
Bradley, who has been justly styled the modern
Hipparchus, combined the habits of accurate
observation with the talent of acute discernment
and felicitous invention. His analysis of the
Aberration of Light furnished the first incon¬
trovertible proof of our Solar System ; while his
fine detection of the Nutation of the Earth’s
i\.xis confirmed the Theory of Universal At¬
traction. Simpson, but above all Maclaurin,
the elegant expounder of the Principia, likewise
materially contributed, by their various mathe¬
matical researches, to the advancement of the
science of Physical Astronomy. Nor was Eng¬
land less indebted to the ingenuity and exqui¬
site skill of her artists, who now constructed in¬
struments of a delicacy far surpassing any for¬
mer attempts, and during the last century fui-
nished for the most part the Observatories on
the Continent.
Though France had for a very long time pro¬
duced nothing in science of much originality or
importance, the munificence of her government
DISSERTATION FIFTH.
693
continued to encourage philosophical pursuits;
and now, hy directing the mensuration of the
Meridian at the most distant points,—within the
Arctic Circle, and under the Equator,—it pro¬
cured accurate data for determining the true
figure of our Planet. It was the more precise
measure of a degree of latitude ascertained hy
Picard, that had at last enabled Newton to sub¬
ject to the test of calculation his grand idea of
extending the power of gravitation from the
earth’s surface, after the simplest law of de¬
crease, to the orbit of the moon. But the satis¬
faction was reserved for the successors of our
immortal chief, to see his determination of the
oblate form of the earth, arising from the mu¬
tual attraction of all its particles, modified by
the influence of centrifugal force, fully confirm¬
ed by a close investigation of the results of the
skilful and laborious observations brought home
by the French astronomers. Nothing, indeed,
contributed so much to exalt the character of
the Newtonian Philosophy on the Continent as
those scientific expeditions; while the credit of
the system of Descartes, which bears no such
scrutiny, rapidly declined. Mathematicians, in¬
vited to a rich field of discovery, were eager to
examine the Principia through all its details;
and the progress which the New Calculus had
made, provided them with instruments for this
dissection. The profound author had left in¬
deed several parts unfinished; of some of the
more difficult problems he had merely sketched
the solution; and he had commonly supplied the
defects of his analytical procedure by the exer¬
cise of wonderful sagacity and penetration.
Maupertuis was the first mathematician of
any note that ventured publicly in France to
espouse the Newtonian Philosophy. But perhaps
no writer contributed more effectually to pro¬
mote its diffusion and popular reception than
Voltaire, whose universal talent ranged through
the sphere of human knowledge, and whose easy
and simple style gave transparency to his con¬
ceptions. The French, at length awakened from
the Cartesian dreams, and directed into the path
of inductive philosophy, again put forth their
inventive powers. The fine genius of Clairaut
and D’Alembert early soared to the highest dis¬
tinction in scientific research. Both these illus¬
trious men showed, from their infancy, the
strongest disposition for mathematical studies,
which they cultivated with the most ardent and
persevering application, and displayed in their
profound investigations all the rich and varied
stores of original invention.
Clairaut began his labours with a capital ex¬
tension of the Theory of Curve Lines. But, in
his riper years, he directed the whole force of his
ingenuity and analytical skill to explore the
depths of Physical Astronomy. He deduced
the figure of the earth strictly from the principle
of universal attraction, with the admission only
of the very simplest conditions. But not con¬
tent with mere speculation, he sought the prac¬
tical solution of that problem, and therefore
eagerly joined the Academicians who were dis¬
patched to measure a degree of latitude within
the Arctic Circle. After achieving this grand
operation, he resumed with vigour the examina¬
tion of the Newtonian System, and concentrated
his utmost exertions in resolving the arduous
problem of the three bodies, or in determining the
influence of a planet or the sun to modify the
motion and orbit of another planet or satellite.
The Integral Calculus furnishes yet no direct or
absolute solution. It became necessary to pro¬
ceed by a train of successive approximations,
simplifying and condensing the computation by
the judicious rejection of the small excrescences.1
But the first result was most perplexing, and
seemed to betray an evident imperfection in the
great Law of Gravitation. Not discouraged, how¬
ever, by this repulse, the persevering analyst
pushed his calculations still farther, and collect¬
ing the minor terms of the series, at last arrived
at a conclusion entirely conformable with obser¬
vation, and thus established beyond all dispute
the harmony of the Theory of Attraction.
But Clairaut did not rest satisfied with specu¬
lative conclusions, however beautiful; he sought
to embody his formulae in real numbers; and
availing himself of the aid of some expert calcu-
1 The question especially selected was the annual change of the position of the axis of the moon’s elliptical path about
the earth, occasioned by solar attraction.
694
PRELIMINARY DISSERTATIONS.
lators, he soon produced a set of Lunar Tables,
much more accurate than had been yet attained.
Encouraged by such eminent success, he now
directed his inquiries to the more distant objects
of our system. The comet, whose return was
predicted by the sagacity of Halley, did not ap¬
pear at the time assigned, and astronomers
began to feel uneasy at their disappointment.
From this state of inquietude they were soon
relieved by the soaring investigation of Clairaut,
who found that the disturbing influence of Jupi-
ter and Saturn would retard for several months
the advance of the distant stranger, and com¬
puted with surprising nearness, from his imper¬
fect data, the time of the comet’s actual appear¬
ance. But excessive application and the solici¬
tations of society preyed on a languid frame,
and premature death tore away that brilliant
genius in the midst of his career of triumph and
applause.
D’Alembert, who rose to still higher celebrity,
and contributed to distinguish the character of
the age in which he lived, closely followed in
this research, though by a different path; en¬
countered similar difficulties, obtained the same
partial result, but finally arrived at a like sa¬
tisfactory conclusion. He carried his acute¬
ness and penetration into all the abstruse de¬
partments of physics, and marked his progress by
originality of conoeption. The success of this
most ingenious philosopher would have been
more complete, if he had confined his views to
the pursuits of abstract science. But he wanted
that patience to which Newton, with innate mo¬
desty, ascribed all his advantages. In discussing
the most arduous questions, D’Alembert advan¬
ced generally by new paths, and displayed great
resources and much versatility of talent. He
would seldom retouch his formulae, or seek to
mould them into simplicity and elegance, and
never submitted to the labour of reducing them
to actual application. Ambitious to excel in
literature as in science, he transferred into his
miscellaneous compositions the same strict logic
and nice discrimination which guided his analy¬
tical researches, and likewise contracted a cor¬
responding style, remarkable for the qualities of
precision and clearness, but possessing no warmth
or elevation.
The last of the three illustrious men who, by
separate roads, arrived at the same conclusions,
and thus concurred in fixing the true system of
the world, was Leonard Euler, horn near Bale
in Switzerland, and educated under the Ber-
noullis, but who, patronised by foreign courts,
passed a very long and most laborious life at
St Petersburg and Berlin. He was indisputably
the greatest analyst that has ever appeared, dis¬
playing infinite address, perspicuity, and ele¬
gance in his mode of investigation, and pursuing
or transforming the most intricate calculations
with such astonishing readiness and rapidity, as
if they seemed only mere pastimes to recreate
his invention. But the supremacy of Euler was
confined to his unrivalled skill in applying ana¬
lysis ; he attained little eminence in philosophy
and general science, and showed no relish for
the charms of literature. His improvements
and discoveries, however, during a life of assi¬
duous and unremitting labour in every branch
of the Calculus, form a monument of the most
stupendous magnitude.
Our island, after the decease of Maclaurin,
produced none to compete with the great ma¬
thematicians of the Continent, except Thomas
Simpson, whose native talent had struggled
through indigence and a neglected education.
He solved with commendable neatness and bre¬
vity several of the difficult questions of Physi¬
cal Astronomy; hut he was deficient in taste
and method, and only followed tardily and at a
distance those masters in science. For a long
period afterwards the inventive genius of Eng¬
land appeared to slumber. The learned were
content with merely commenting on the Prin-
cipia, but rarely borrowing a few scattered lights
from abroad. The current of investigation was
diverted into other channels, or absorbed among
humbler objects. In the meanwhile, a new and
brilliant science, beyond the dominion of Me¬
chanical Philosophy, had been gradually forming,
to which our experimenters contributed their
full share. Electricity captivated its numerous
cultivators by surprising and splendid displays 3
hut though it engaged the imagination, it afford¬
ed little exercise to the judgment, and was not
fitted to call forth the higher mental energies.
The application of English talent was now
DISSERTATION FIFTH.
695
mainly directed to the improvement and exten¬
sion of the mechanical arts, though perhaps few
nations in Europe have less availed themselves
of the results of abstract science towards aiding
and correcting the operations of practice.
In the career of the sublimer sciences, the
Continent for a long time afterwards maintained
its ascendancy, which was secured by the very
superior skill displayed in managing the integral
calculus, with its improved and refined notation.
But a succession of minor discoveries continued
to expand and consolidate every department of
Natural Philosophy. Daniel Bernoulli, the most
amiable, if not the most ingenious of that shin¬
ing family, embraced with candour the doctrine
of Newton, and likewise evinced, in all his phy¬
sical researches, a considerable share of the sa¬
gacity and singular address which so eminently
distinguished that great master. The attention of
Lambert was diverted to a wide variety of pur¬
suits, and his original and excursive mind shed
new lights on every subject it explored. He
conjoined analytical skill with the talent of ex¬
perimental research. But unfortunately he con¬
tented himself in operating with rude instru¬
ments, and commonly trusted to the probability of
rectifying such imperfect results by the help of
combined calculations. If Mayer had not the
same reach and versatility of genius, he pos¬
sessed that inciting ardour and unconquerable
perseverance which enabled his discrimination
to erect a durable monument. Adopting the
clear formulae of Euler for the several elements
of the moon’s motions, he deduced the indeter¬
minate co-efficients from a strict and most labo¬
rious comparison of Bradley’s observations, and
by thus poising and adjusting the numerical
quantities, he framed a body of Lunar Tables,
which has long been regarded as a standard of
excellence. It is thus that England has generally
supplied the means which rendered the conclu¬
sions of the Continental mathematicians really
available. The reflecting instrument of Hadley,
the achromatic glass of Dolland, and the divid¬
ing machine of Ramsden, have, in succession,
mightily contributed to the progress of practi¬
cal astronomy. The numerous observations of
Bradley and Maskelyne furnished the correct
data which guided Lagrange, Laplace, and Gauss,
through all their profound researches, to the dis¬
covery of the cyclical and reciprocating motions
of the heavenly bodies. The various disturbing
causes incessantly in operation are, after the lapse
of certain vast periods, again renewed and repeat¬
ed in the same order of succession, and thus pre¬
serve the fine harmony, and maintain the per¬
manent stability, of the Universal System.
The British mathematicians had long neglect¬
ed the cultivation of the Higher Analysis, and
were perhaps the more disposed to overlook its
pre-eminent advantages, from observing the
course of their brethren on the Continent, who,
on various occasions, after magnificent displays
of the powers of calculation, but either from
their incomplete integrations or the defective
statement of the physical principles, arrived
merely at the same imperfect conclusions that had
been discovered before by much simpler means.
Our island has at last resumed its proper sta¬
tion in the loftiest departments of science.
Emancipated from the trammels of a narrow
notation, the more aspiring votaries pursue with
ardour the most refined calculus; while they
guide its application and avoid its abuse by the
infusion of that spirit of purity and elegance de¬
rived from the discipline of the ancient geome¬
try. Among the illustrious few whom foreign
nations would adopt with distinction, we may
cite the gifted individual who, rivalling the
fame of Lagrange and Laplace, has, in his
beautiful solution of the problem of the Attrac¬
tion of Spheroids, struck out a new and direct
path, which completely throws into the shade
their very laborious and perplexed trains of in¬
vestigation.
Having traced the great outline, it only re¬
mains to sketch the plan of this Dissertation. I
shall arrange Mathematical and Physical Science
under the two great heads—of Pure or Specula¬
tive Science—and that of Applicate or Practical
Science; each of these again to be classed in subor¬
dinate divisions. Pure Mathematical Science
includes Geometry, Arithmetic, Algebra, and the
Higher Calculus. Its applications are very nu¬
merous and diversified; but without pursuing the
details, our attention will be mainly directed to
the progress of general and pervading principles.
696
PRELIMINARY DISSERTATIONS.
Physical Science occupies a confined, space till
it receives the accession of Mathematics) with
which it becomes always the more blended in
proportion as it improves and expands. Pure
Physics at present appears limited to IVlagnetism
and Electricity, which have yet drawn scarcely
any aid from the disquisitions of Geometry.
The infusion of Mathematics into Physics, and
the application of Physical Science to the Prac¬
tical Arts, led to the most wonderful results,
which have aroused the ingenuity and vastly
multiplied the productive industry of the eigh¬
teenth century. Applicate Physical Science em¬
braces Dynamics, Hydrostatics, Pneumatics,
Optics, Electricity, Magnetism, the Doctrine of
Heat, Meteorology, Geography, and Astronomy.
In discussing these important subjects, separately
or inclusively, incidental lights will be reflected
on General Mechanics and the Elements of Naval
Architecture.
SECTION I.
SPECULATIVE MATHEMATICS.
1. GEOMETRY.
Pure Geometry is in strictness limited to
the mere equality of lines, angles, and spaces,
whether superficial or solid. It owes its main
extension to the principle of comparison or the
doctrine of proportion, which is really but an
application of Arithmetic, the idea of Number
being transferred to Quantity or Magnitude by
a process of subdivision. Such concert has pro¬
duced the most perfect of abstract sciences, and
erected the noblest monument of the genius and
invention of the ancient Greeks. That acute
people nearly completed the Elements of Geo¬
metry; and carrying their speculations beyond
the properties of the Circle, they investigated
the Sections of the Cone, and traced the charac¬
ter of some of the Higher Curves. The demon¬
strations left by the Greek Geometers are models
of accuracy, clearness, and elegance—admirably
calculated for training the minds of youth to
habits of close reasoning and luminous arrange¬
ment. The circumspection of those great instruc¬
tors of mankind in distinguishing the several
cases, and marking the limitations of a proposi¬
tion, though frequently bordering on prolixity,
might serve to warn the rapid cultivator of Alge¬
bra against indulging the tendency to hasty gene¬
ralization which has given rise to the various pa¬
radoxes, and even palpable absurdities, that still
disfigure the excellence of the modern art. The
method of Geometrical Analysis, which investi¬
gates the construction of a problem, by remount¬
ing from its conditions along a chain of depend¬
ence to some known property, affords decidedly
the best exercise and initiatory discipline for the
student in Mathematics. It imbues the mind
with a taste and elegance which insensibly extend
their influence over the culture of the other sci¬
ences. The most curious and difficult portion,
however, of the Greek Geometry, has unfortu¬
nately been transmitted to us in a mutilated and
imperfect state, which has often tortured the
skill of commentators and mathematicians to
restore it. Soon after the revival of letters, the
principal works of the Greek Geometers were
translated in Italy by Commandine; but of
Apollonius’ Conics several books are wanting,
and some parts of the Collections of Pappus ex¬
hibit only detached fragments. Near the close
of the sixteenth century, and early in the seven¬
teenth, Vieta, from a few scattered hints, re¬
stored the lost Tract on Tangencies, Fermat
framed some beautiful separate demonstrations,
and Snellius reproduced the Plane Loci, but in
a tasteless shape. Soon afterwards Viviani, the
surviving disciple of Galileo, supplied the fifth
book of Apollonius, and with such remarkable
DISSERTATION FIFTH.
697
success, that on comparing his production with an
Arabic version just then discovered, he appeared
to have surpassed his original. Huygens1 after¬
wards gave, in the purest taste, some specimens
of the Ancient Geometry. A Collection of the
Mathematical Treatises of the Greeks respecting
the Art of War was now published in a magni¬
ficent folio from the Royal Press at Paris. But
a more extensive undertaking was planned by
our oriental traveller Bernard, to print at Ox¬
ford a complete series of the Greek Geometers,
filling up the blanks from the inspection of
Arabic Manuscripts. In pursuance of this
scheme, Hr David Gregory2 edited Euclid, and
Dr Halley3 Apollonius, while he restored like¬
wise the Tracts on the Section of Ratio and
of Space. After an interval of fourscore years,
Torelli’s4 elegant edition of Archimedes, pur¬
chased in Italy, has issued from the same press.
Every lover of science would rejoice to see a
portion of those ample funds that have been
provided at Oxford for the encouragement of
such expensive works, appropriated to the repub¬
lication of Pappus’ Mathematical Collections,
of which several manuscripts exist far more
complete than the copy printed by Comman-
dine.
The relish for the Ancient Geometry has been
1 Born at the Hague in 1629, and son of the Lord of Zuylichen, Secretary to the Prince of Orange; completed his ma¬
thematical studies at Leyden under Schooten, and printed a beautiful tract on the Circle and Hyperbola in 1651. But af¬
ter visiting different countries, he published in 1658 his original and immortal work entitled Horologium Oscillatorium.
Having successfully applied the pendulum and the spiral spring to regulate the motions of clocks and watches, he was
anxious to accommodate those instruments to the finding of the longitude at sea. For that purpose he visited England,
where he was treated with distinction; but returning in 1663 through France, he was induced by the Minister Colbert
to accept of a large pension, and fix his abode at Paris. There he resided till his health became impaired, and in 1681 he
retired to the calmer enjoyment of his native country. The same pursuits, however, engaged his attention, till his death
at the Hague on the 8th of June 1695. He was one of the clearest writers and most elegant geometers of modern times,
and his powers of invention have seldom been surpassed. The finished works of Huygens have been collected at two seve¬
ral times into three quarto volumes.
2 Nephew to the famous James Gregory, born at Aberdeen in 1661, completed his education at Edinburgh, and was ap¬
pointed Professor of Mathematics in that University in 1683, the office having been suffered to remain vacant for eight years
after the death of his uncle. In 1691 he had sufficient interest to obtain the Savilian professorship at Oxford, and had the
honorary degree of Doctor in Physick conferred on him by the University. He published his Elements of Astronomy in
1702, and in the following year brought out his Edition of Euclid. He had made some progress in preparing the Conics
of Apollonius, but fell a sacrifice in 1710 to an attack of malignant small-pox, at Maidenhead, where he chanced to stop at
the Inn, on his return from a visit to Bath. He possessed some learning, but his genius was of a very inferior order to that
of his uncle.
3 Edmund Halley, born in London October 29.1656, the son of a substantial citizen—educated at St Paul’s school, and sent
to Oxford in 1673—sailed for the island of St Helena in November 1676, and returned with his catalogue of fixed stars
after an absence of exactly two years—elected immediately fellow of the Royal Society, and deputed by that learned body
in 1679 to visit Hevelius, at Dantzic, and examine his observatory—spent the years 1680 and 1681 in France and Italy.
In 1684, having turned his attention to Kepler’s problem, he tried, as some other mathematicians about this time had done,
to derive it from a graduating central force, but was unable to find a geometrical demonstration ; and not obtaining any
help as he expected in this investigation from Hooke or Wren, he had recourse to Newton, who astonished him at Cam¬
bridge by the store of his grand discoveries, condensed into eight general propositions. He overcame the scruples of the
modest philosopher, and prevailed with him to arrange the materials of the Principia, of which he superintended the pub¬
lication in 1687, having written the preface and some elegant recommendatory verses. Halley now gave a geometrical
construction of the higher equations, computed the effects of evaporation in the IMediterranean, and formed tables of life
annuities. For the purpose of improving Nautical Science, he had the command of the Paramour Pink, with which he
sailed from England on the 24th November 1698, traversed the Atlantic, and crossed the Equinoxial Line; but his crew
growing sick and mutinous, he was obliged to return in the following June. Invested with fuller powers, he set sail again
in September, and spent twelve months in exploring both hemispheres, and during the year after his return, he delineated
and published his famous magnetical chart. He was next employed on a survey of the British Channel, and^ then sent by
the English Government to assist her ally the Emperor of Germany in forming a harbour at the bottom of the Adriatic.
On his return he was appointed, in November 1703, Savilian Professor of Geometry at Oxford, having been thwarted before
in a similar canvass by clerical influence. He now set about recovering the works of Apollonius ; studied as much Arabic
as enabled him to translate the tract on the Section of Ratio, and he restored the other tract on the Section of Space from
the hints left by Pappus. These pieces, in a small octavo volume, appeared in 1706; but four years afterwards came forth,
in a splendid folio, his edition of the Conics, with the eighth book restored, and the additional treatise of Serenus. In
1719 Halley was appointed astronomer royal, and resided at Greenwich during the rest of his life, devoting his advanced
age to the careful and assiduous observation of the Heavens. He completed even his projected task of embracing a lunar
period of eighteen years. A paralytic disorder seized him in 1737, from which he partially recovered, but his strength declined
insensibly, and he expired on the’ 14th of January 1742. Few philosophers have contributed more largely to the advance¬
ment of useful knowledge. Ingenuity, ardour, indefatigable perseverance, learning, and general information, were pos¬
sessed by Dr Halley in a most eminent degree; and having mingled in the active scenes of life, he had the rare advantage
of conjoining the love of study with the habits of social intercourse.
4 Born in 1721 at Verona, where he died in 1781. He studied at Padua, and became a great linguist, a good mathe¬
matician, and an excellent critical scholar. Being in easy circumstances, he devoted his whole time to literary pursuits,
and carried his admiration of the Ancient Geometry almost to a pitch of bigotry.
DISS. V. 4 T
698
PRELIMINARY DISSERTATIONS.
longer preserved in Italy and in England than
over the rest of Europe. But no person evei
cultivated that fine science with more assiduity,
perseverance, and success, than our countryman
Dr Robert Simson1 of Glasgow, the learned and
critical editor of Euclid’s Elements. In this
department he concentrated his whole efforts, and
appears, from his familiarity with the ancient
mode of demonstration, to have inhaled the very
spirit of the Greeks. In 1749, he published his
Restoration of the books of Apollonius on
Plane Loci, which by its fulness and peculiar
elegance leaves scarcely a shadow of regret for
the loss of the original. Simson pursued his
researches in the Ancient Analysis through a
long life, and not only restored various frag¬
ments, but threw light on some very difficult
and abstruse questions connected with it. A
posthumous volume, printed in 1776, at the ex¬
pence of Earl Stanhope, besides many fine geo¬
metrical speculations, contains the first satisfac¬
tory exposition of Porisms, of which the defini¬
tion advanced by Pappus had been commonly
regarded as an incomprehensible enigma. But
from the unvarying tenor of his studies, the
Scotch professor became a rigorist for the An¬
cient Analysis, and rejected with disdain the most
obvious improvements in the form of exhibition.
It deserves remark, that mathematical demon¬
stration, being addressed to the eye rather than to
the ear, must attain its greatest perspicuity when
the successive steps of reasoning are seized at a
glance. This is effected by adopting the sym¬
bols of Algebraic Notation, the most concise and
perfect of all written characters; nor is the
beauty and logical accuracy of the procedure in
any degree impaired by such a transparent cover¬
ing.
Dr Matthew Stewart3 of Edinburgh, who had
been the pupil of Dr Simson, and possessed a
X Born at Kirtonhall in Ayrshire on 14th October 1687, studied at Glasgow, and made such progress in elementary geo¬
metry that at the early a"e of 22 he had an offer of the professorship of mathematics, which was immediately expected to be¬
come vacant in that University. Feeling his deficiency, however, he obtained leave of a year’s absence, which he spent
in London under the tuition of Humphry Ditton, and was admitted to the chair on the 20th of November 1711. His
time seems afterwards to have been mostly spent in discharging the duties of his office, the intervals being allotted to the
solution of geometrical problems, the perusal of the older mathematicians, and to miscellaneous reading. He led the life
of a recluse, and all his steps were formal and methodical; yet his disposition was amiable, and he indulged at stated times
in easy conviviality. He sent two papers, geometrical and algebraical, on Indeterminate Problems, to the Royal Society m
1723 and 1753, gave his restoration of the Loci Plani in 1745, published his Conic Sections in 1735, produced the Latin edition
of Euclid’s Elements in a quarto volume in 1756, which he compressed in 1760 into an English octavo, to which he annexed
the data in 1762. It contains only the first six books of the original, with the eleventh and twelfth, the rest of the books
being omitted as of little consequence in the present state of science. Perhaps the selection should have been carried far¬
ther. This edition is correct and creditable to the compiler, and has obtained prodigious success. -^'ay5 6ie veiy Scotti¬
cisms with which it abounds appear now to be adopted at Oxford and Cambridge as the appropiiate diction of the Ancient
Geometry. Simson quite idolized his original. He had a fine taste for geometry, some talents of invention, and consider¬
able attainments as a scholar, but without any great force of intellect. In his latter years, from excessive veneration of
the Greek Geometry, he not only viewed the Cartesian method with aversion, but began to regard the I luxionary Calculus
with mistrust and suspicion. He became emeritus professor in 1761, and died on the 1st of October 1768.
2 Born in 1717 at Rothsay, in the Isle of Bute, of which place his father was minister ; studied seven years at Glasgow,
where he distinguished himself; to gain farther instruction, in 1741 he removed to Edinburgh, wheie he cultivated the
society of the celebrated Maclaurin, while he corresponded with Simson, his old master. He now prosecuted geometrical
studies with ardour, and put forth his uncommon powers of invention ; and after he became minister at Roseneath, he found
leisure in that seclusion to continue his favourite pursuits. On the occasion of a vacancy of the mathematical chair at Edin¬
burgh by the death of Maclaurin, he was induced to draw out the substance of his most profound geometrical investigations,
which he printed under the title of General Theorems, in a small volume, about the close of 1746. This publication se¬
cured his election, and after some delay he was appointed professor in September 1747- He now enjoyed a situation most
congenial to his taste, and favourable to the exercise of his rare talents. Ambitious to apply his beloved geometry to un¬
ravel questions which were believed to demand all the resources of algebraic art, he discovered a solution of Kepler s pro¬
blem at once simple and direct, and greatly surpassing in beauty the more laboured efforts of calculation. . This investi¬
gation was inserted in the second volume of the Transactions of the Edinburgh Society, which appeared in 1/56. En¬
couraged by such success, he five years afterwards produced his Physical and Mathematical Tracts ; a very ingenious and
elegant work, which would have been clearer had the author only admitted an abbreviation by the simpler algebraic
symbols. About this time the results of the observations of the Transit of Venus, which had been expected to give the
true distance of the Sun, were found to be unsatisfactory and discordant. Stewart therefore published in 1763, as a
sequel to his Tracts, a theoretical solution of the problem; in which he was directed by Geometry to the exact motion
of the Lunar Apogee, a question that, since the analysis of Newton, had perplexed the greatest mathematicians. . But he
was not equally felicitous in Determining the Solar Distance, which required the inversion of the problem, and involved
some deceitful and precarious compensations of error. This pamphlet was his last production, having printed only a few
months before an octavo volume under the title of Propositiones More Veterum Demonstrates. These propositions^ however,
derive their value merely as exercises of the method of conducting geometrical analysis and synthesis. But his lamp of
genius was already nearly extinguished. Dr Stewart fell into a state of bad health, and having devolved the charge of
teaching on his son, then a youth of the highest promise, he retired in 1772 to a small paternal property in Ayrshire,
w here he chiefly spent the rest of his days, and died on the 23d of January 1785.
DISSERTATION FIFTH.
much richer invention, was likewise an able
and zealous promoter of the Greek Geometry,
which he directed besides to the investigation of
certain difficult parts of Physical Astronomy.
But though managed with sufficient address,
the instrument he employed was hardly fitted
for exploring the more abstruse and recondite
problems, which often require all the concen¬
trated powers of the Modern Analysis. The
conclusions at which he arrived display much
elegance, though merely approximative, and
devoid of the precision that is indispensable in
the present advanced state of Astronomical
Science.
I need not stop to notice the attempts of other
English mathematicians, to restore some frag¬
ments of Apollonius. After the principal de¬
monstration was obtained, there could be little
difficulty in evolving its different phases, and
modifying it to the several cases. Playfair’s
elucidation of the nature of Porisms is entitled
to higher distinction.
It has often been matter of surprise, that the
Greeks should have spent so much ingenuity,
and set such a high value on the Geometrical
Construction of Problems. But the application
of Geometry served them in some measure the
purpose of calculation, and became a sort of
substitute for the tedious and laborious opera¬
tions of their imperfect system of Arithmetic.
Accustomed, as we are, to the extreme facility
of computing by help of the Arabic ciphers,
we can form no adequate conception of the toil
of working with alphabetic numerals, though
the Greeks had made some capital improve¬
ments in their system of notation. They could
extract laboriously the Square Root of a num¬
ber, but never attained the extraction of the
Cube Root, which it appears was first discovered
many centuries afterwards by the Arabians.
Hence undoubtedly the solicitude of the Greeks
to solve, by a Geometrical, or even a Mechani¬
699
cal Construction, the famous Delian Problem,
or the Duplication of the Cube.
It would seem that, in finding the square root,
the Greek mathematicians must have employed
certain methods of abbreviation which are not
explained. Archimedes, in his famous Quadra¬
ture of the Circle, to which he approximated by
measuring the successive inscribed and circum¬
scribing polygons, having occasion repeatedly to
extract the square root, expressed the value by
fractions, and yet with such felicity as always
to adopt the lowest integral numerator and de¬
nominator. He thus discovered that the cir¬
cumference of a circle is less than 3} times and
greater than 3^ times its diameter, or that their
ratio lies between the ratios 7 to 22 and of 71
to 223.1 This approximation within the limits
of the 2000th and 4000th parts, might be suffi¬
cient for ordinary practice. But Apollonius and
Ptolemy afterwards approached a hundred times
nearer. Yet no farther advances were made
in solving that important problem, which re¬
quired the most refined address, till the lapse of
near a thousand years, when the Arabians be¬
came possessed of the denary system of notation,
and carried the expression for the circumference
of a circle to ten decimal places. But this elabo¬
rate result was imperfectly known to the revi¬
vers of science in Europe ; and Vieta, Adrianus
Romanus, and others, exerted their ingenuity and
patience in extending the earlier solution. The
simplest and most elegant is that of 113 to 355,
an approximation differing scarcely by the ten
millionth part from the truth, which was disco¬
vered about the year 1585 by the elder Adrian
Metius, a military engineer in Holland. His
countrymen Van Keulen and Snellius, in the
next century, pushed the expression for the cir¬
cumference of the circle to 35 figures. But the
progress of the higher analysis opened more easy
and rapid modes of approximation. In the early
part of the eighteenth century, Sharp2 and Ma-
1 This ratio, it may be observed, is easily derived from the limits assigned bv Archimedes, for 71 + 7x 6 = 113,
and 223 + 22x6 = 355.
2 Abraham Sharp, born at Little Horton, in the West Hiding of Yorkshire, in 1651, was apprenticed to a merchant at
Manchester; but preferring the study of mathematics, he supported himself by teaching a school in Liverpool. Here he en¬
gaged as amanuensis to Flamsteed, and became his assistant when the Royal Observatory was erected at Greenwich in 1676.
His services were most eminent in every department. He constructed optical and astronomical instruments, observed
stars, calculated tables, and delineated celestial charts. His peculiar neatness of execution is displayed in a small geo¬
metrical work which he published in 1717- About that time he seems to have retired to his native village, where he led
the life of a hermit, but esteemed for his quiet and beneficent disposition. He died in 1742.
700
PRELIMINARY DISSERTATIONS.
chin1 computed in England the quadrature of
the circle to 75 and 100 places of decimals, and
Lagny in France advanced to 128 figures. But
these labours were outdone hy Vega,2 an officer
of artillery in the Austrian service, who amused
his leisure during a campaign, in employing
one of Euler’s formulae to derive the length of
a quadrant from the tangents of fractional
arcs, carried the expression to 140 decimal
places. This was the luxury of calculation;
and though no doubt superfluous, it might at
least convince any judicious person of the
impossibility of stating the ratio of the diame¬
ter to the circumference in finite terms. Yet
the squaring of the circle is a problem which
has at all times fascinated the attention and
bewildered the reason of many superficial or an¬
tiquated students in Geometry. The incom¬
mensurability of the circle, which James Gre¬
gory had attempted to prove in 1661, was finally
demonstrated a century afterwards by Lam¬
bert, from an ingenious transformation of the
known series for the quadrantal arc in terms
of its tangent or the radius. The same inge¬
nious mathematician likewise proposed several
neat geometrical constructions, for approximat¬
ing to the length of arcs of a circle still more
nearly than the methods given by Fermat, Gre¬
gory, Huygens, and others.
Elementary Plane Geometry rests on the com¬
bined properties of the straight line and the circle.
Many important additions have been made to
the digest of Euclid; and several eminent ma¬
thematicians of the eighteenth century have cor¬
rected, simplified, and essentially improved the
only valuable portion of the large work.5 Some
1 John Machin, elected professor of Astronomy in Gresham College in 1713, and became secretary of the Royal Society.
He had the reputation of being an able mathematician, yet his essay on the Laws of the Moon’s Motion, in which he at¬
tempted to rectify the Principia, was but a superficial performance. He died in 1751. . , . ^ ^ 4 ,
2 This excellent mathematician, who published in 1794 a complete collection of Logarithmic James and Analytical
Formula, was eight years afterwards robbed and barbarously murdered by a miller, in whose house he lodged, and his body
thrown into the Danube.
3 It may be sufficient perhaps to notice the Elements of Geometry by Thomas Simpson, and the similar treatises in the
French language by Clairaut and Legendre. These productions all unite clearness with precision ; and excluding whatever
appears superfluous, they still comprise the whole series of connected propositions. Simpson’s unpretending volume is neat
and very brief, yet sufficiently perspicuous. The Geometry of Clairaut is still shorter, but has an air of originality, being
designed to show the road of induction, or to guide the learner through his efforts at the solution of geometric problems,
to discover the great elementary truths. He followed the same plan, and with more complete success, in his excellent
Elements of Algebra. But the Geometry by Legendre claims much higher merit, and is perhaps the best on the whole
that has yet appeared. It were vain, however, to expect perfection: the steps of his demonstrations are sometimes incom¬
plete, and his entire separation of the problems is at least a very questionable improvement. I he notes he has added are
valuable, but appear disproportioned to the text, and certainly too profound for beginners. This elegant geometer attempt¬
ed to found the comparison of triangles on abstract considerations derived from the common theory of functions. But
such reasonings a priori are fallacious, involving unperceived some metaphysical assumptions.
The works now mentioned might suffice for the instruction of practical or professional men; but the pursuit of a liberal
education aspires to greater attainments. The main object is to sharpen the faculty of perception, and invigorate by due
exercise the tone of the intellectual powers. For contributing to that effect, the fulness and circumspection of the an¬
cient mode of demonstration are admirably calculated. It seemed, therefore, an estimable task to select the scattered
wrecks of the Greek Analysis, and dispose them into a form accessible to ordinary students. The beauty of the pro¬
positions concerning Loci was particularly striking. _ _ . . „
It ivould be preposterous, however, to hold up the Elements of Euclid as a standard of instruction in Geometry for the
present day. They were composed before the invention of Trigonometry, and probably designed chiefly as an introduction
to the Pvthagorean Philosophy. Hence the large portion of them devoted to the relations of numbers, and the properties
of the regular polygons and solids. By common consent, therefore, the greater part of the system is now laid aside, and
the other boohs are commonly altered or curtailed in practice. Many trivial propositions occur in the third bookseveral
of the fourth have little interest; and it may abate that extravagant praise which several mathematicians have lavished on
the Doctrine of Proportion contained in the fifth book, to know that it really cannot be taught. But the language em¬
ployed in that celebrated compilation, for want of appropriate technical terms, is often vague and indistinct Ihe
word angle, for instance, has no less than three different significations; and other examples of a like confusion might be
easily cited. In some cases, the demonstrations of Euclid are imperfect or inconclusive. Thus, the reasoning in the twenty-
fourth proposition of the first book applies only to the particular position of the figure; an objection first started by Ihomas
Simpson, to the great annoyance of his critical namesake. But similar oversight was made in the demonstration of the
seventh proposition of the same book, which fails if the figure be changed. Both these propositions are only of conse¬
quence as auxiliaries in the train of combination. But of the fundamental property of parallel lines, the demonstration
rests on the mere assumption of an intricate axiom. In a few cases the reasoning is unnecessarily complicated, from the
peculiar conceptions of the author. Thus, the noted fifth proposition of the first book is of that description. Its demon¬
stration implies the reversed application, at least mentally, of the isosceles triangle; but Euclid evades or disguises the pro¬
cess, by producing the sides of the triangle, and forming two interwoven triangles, which are virtually adapted by inver¬
sion, and the annexed triangles being then taken away, the equality of the angles at the base hence follows- But the last
is the only step wanted, and the other two were evidently superfluous. This stumbling proposition has been called the
Pons Asinorum; and no wonder that the beginner should feel puzzled at seeing such a parade of argument end in so plain
a result.
DISSERTATION FIFTH.
701
remarkable propositions, derived from sources
beyond the usual scope of Geometry, are yet as¬
similated with that science. Of such accessions,
one of the most beautiful is the late curious and
unexpected discovery of Gauss, that, besides
the ordinary regular polygons, a numerous class
more complex, including the next polygon of
seventeen sides, are capable of being inscribed
within a circle, by a mere geometrical construc¬
tion. 1
In solving the common problems, the straight
line and the circle are generally combined, which
requires the application of both the ruler and
the compasses. Schooten effected by the ruler
alone several simple constructions, of use parti¬
cularly in castrametation. But the late Masche-
roni2 of Bergamo, in a small work which appear¬
ed in 1795, made a beautiful addition to Ele¬
mentary Geometry, by the solution of a variety
of problems, especially those concerning the in¬
scription of the regular polygons, with the help
exclusively of compasses. Suck speculations,
however, are in a great measure extraneous to
the science.
The theory of Lines of the Second Order
forms one of the finest speculations of the more
advanced geometry. These curves were derived
from the Section of the Cone; but the clearest
and most philosophical way of treating them is
by considering their description on a plane.
The distinguishing property of the foci was
known to Apollonius, but the advantage of its
application overlooked. The Parabola forms
the intermediate transition of the Ellipse to the
Hyperbola, the remote focus stretching farther
out, till it vanishes into indefinite space, again
to re-appear on the opposite side. The features
of the Parabola are therefore not strictly includ¬
ed in the phases of the Ellipse and Hyperbola.
The more comprehensive relation of the dis¬
tances of any point in the curve from a focus
and the directrix is mentioned by Pappus, but
the beauty of that locus was not perceived till
Boscovich, in 1752, deduced the properties of
those lines from it in a string of corollaries,
more ingenious than elegant. This essay was
compressed and methodized by Thomas New¬
ton in 1794; and in the same year Walker, a
respectable mathematician, unaware of what
had been already done, produced a work on a
similar plan, of which the first part occupied a
quarto volume, composed indeed after the man¬
ner of the ancients, but so exceedingly prolix in
diction as to have very few readers.
An elegant mode of investigating curves of
the second or higher orders, is to consider them
as generated by the conditional intersection of
angles or lines turning about fixed points or
poles. The property had been stated generally
in the Principia, but was expanded in 1720 by
Maclaurin in his Geometria Organica. The in¬
tersections of Polar Radiants were discussed by
Brackenridge in 1733. The subject has been
again revived, and prosecuted with great inge¬
nuity and research, by the celebrated Carnot,
under the denomination of Transversals.
No part of Geometry has been more improved
in the course of the last century than Trigono¬
metry, which is not only simplified but much ex¬
tended in its application. The theory of planes
and solids has likewise been cultivated with emi¬
nent success. As the position of a point on a
plane is assigned by referring it to two co-ordi¬
nate lines, so the place of a point in space may
be determined by its distances from three planes
which are mutually perpendicular. The proper¬
ties of a line of single curvature may be derived
from the equation of its co-ordinates; the pro¬
perties of a curved surface can likewise be de¬
duced from its triple shades, or the perpendicu¬
lar projections on the three planes. Such is the
process employed by Monge3 * in his Descriptive
1 Gauss found that the expression for the multiple cosine is always decomposable into binomial factors, and hence con¬
cluded that any regular polygon, the number of whose sides is a prime, and denoted by 211 + 1, may be inscribed in a circle
by mere Elementary Geometry. These numbers form the series 3, 5, 17, 257, 65537, &c. of which the first two only were
known before.
2 Born in 1750; died at Paris, July 14, 1800. His tract on the Compasses happening to fall into the hands of General Bo¬
naparte during his first triumphant campaign in Italy, this extraordinary man was so struck with its ingenuity, that, on
his return to Paris, he communicated, in conversation, some of the propositions to the members of the Institute. The
book was immediately translated into French, and the author promoted to a place of trust and emolument in the Italian
Republic.
3 Gaspard Monge, born in 1746 at Beaune, and educated at the Jesuits’ seminary at Lyons. His uncommon talent for
drawing procured him admission into the Military School at Mezieres, where he soon became assistant teacher. Disgusted
702
PRELIMINARY DISSERTATIONS.
Geometry, which may be considered, as the com¬
pletion of the analytical method of Descartes.
It furnishes direct and general solutions of se¬
veral important problems, especially of those re¬
lating to the intersection of planes and the con¬
stitution of solids. Descriptive Geometry com¬
prehends also the theory of Perspective, which
was founded by Ubaldi, and long afterwards re¬
cast and simplified by Brook Taylor, and ren¬
dered still more practical by Lambert.
2. ARITHMETIC.
To express large numbers by continued addi¬
tions being impossible, it soon became neces¬
sary to arrange them on a scale of ascending
progression. The simplest mode was evidently
to repeat the same root of the scale; and as men
in the earlier periods of society used to reckon
with the ten fingers of both hands, they were
led by Nature herself to frame the Denary Sys¬
tem of Numeration. If they had likewise form¬
ed marks for a Digital Notation, they would have
completed the bases of Arithmetic. But un¬
fortunately the Alphabetic Characters had been
introduced before distinct symbols were con¬
trived to represent numbers. The letters design¬
ed merely for written language, came hence
among all nations to be employed besides in
numeral notation, though hardly manageable,
and ill adapted to any regular system of arrange¬
ment. In the application of those characters
the ancient Greeks showed great ingenuity, by
distinguishing them into three classes, appropri¬
ated to the ascending progression of units, tens,
and hundreds. In this way they reached the
term of a thousand, and by employing as an
auxiliary the capital M, they could indicate
myriads or ten thousands. The triple series of
thousands up to a million were more easily
denoted, however, by placing a dash under
the successive sections of letters. But Archi¬
medes indicated a mode of obtaining almost un¬
bounded extension of this system, by decompos¬
ing the elements of the notation into periods of
ascending myriads. Apollonius simplified the
plan, by adopting a thousand as the root of the
progressive scale. Had he proceeded only a
little farther, and rejected the letters, except the
first class denoting digits, he would have render¬
ed his notation perfect, and have achieved one
of the most useful and prolific discoveries ever
made. Ptolemy afterwards advanced much
nearer to this ultimate object, by employing, in his
Trigonometrical Tables, the descending Sexagesi¬
mal Scale, suggested by the subdivision of the cir¬
cumference of a circle into degrees, of which
or the root of this scale, correspond nearly to the
length of the radius. It would seem, however,
that, during the interval between Archimedes
and Ptolemy, the Greek Arithmetic had receiv¬
ed some essential improvements in practice; for
the Sicilian geometer, by a very tedious and
operose process, of which he gives merely the re¬
sults, was content with stating the ratio of the
diameter to the circumference of a circle as in¬
termediate between that of 7 to 22 and of 71 to
223, differing therefore by a 1200th part from
the truth; whereas the chords computed by the
astronomer of Alexandria for every half degree
of the semicircle are correct to the last place,
and consequently never deviate by a 300,000th
part of the whole.
with the tedious and operose methods of calculation then practised among engineers, he sought to shorten the road by recur-
ring to general principles and the aid of Geometry. Thinking closely on that subject, he matured a regular system, which
has changed the theory of planes and solids. The ardour of his pursuits was infused into his pupils, and the frequent com¬
munications he made to learned societies rapidly extended his fame. In 1780 he was conjoined with Bossut as acting pro¬
fessor ot Hydrodynamics at the Louvre, a place erected by the patriotic minister Turgot, which required him to reside at
Paris only during half the year. But three years afterwards, on being appointed to succeed Bezout as Examiner of the
Marine, he fixed his permanent abode in the capital, and engaged in the experiments and discussions of the philosophers.
He became a warm partisan of the Revolution, and contributed his utmost efforts to promote the various plans adopted
by its leaders. But he deserved praise for the great concern he took in founding the Polytechnic School, an institution
eventually productive of the very best effects. Having accompanied Bonaparte to Egypt, he returned with the fruit of
his observations to share in the fortunes of that wonderful man. He resumed with lustre the place of professor, and con¬
tinued to delight the numerous pupils by his kind attention and the clearness and expansion of his oral discourses. But
on the second^ return of the Bourbons in 1815, he felt the weight of their vengeance. The Institute was remodelled, and
the Polytechnic School suppressed. This sad reverse preyed on his spirits, and produced alienation of mind; in which me¬
lancholy state he languished for some time, and expired on the 28th July 1818.
DISSERTATION FIFTH.
703
The Romans, who cared only about objects of
vulgar ambition, overlooked the refined mode of
Greek Notation, and remained satisfied with their
own very clumsy and involved system, which
could with difficulty represent a large number,
but was absolutely disqualified for serving in
any way the purposes of calculation. They were
obliged therefore to have recourse to counters,
and by help of the Abacus, or decimal board, they
performed the ordinary operations of summing
accounts. This humble expedient was practised
in Europe till the seventeenth century, and is
still used by the traders throughout the Chinese
Empire, its application being there facilitated
by the prevalence of the decimal subdivision of
weights, measures, and coins.
The discovery of the Denary Notation, so beau¬
tiful and simple in its application, is commonly
referred to India, though neither the place nor
the date of its origin has been ascertained. It
was unknown to the Arabian astronomers till
near the close of the eleventh century of our era,
and even at this period its expressions appear
sometimes intermingled with the alphabetic nu¬
merals. But the advantages of the system were
soon perceived; and the Tables of Sines and
Tangents calculated by those laborious mathe¬
maticians are now found, from examination of
the manuscripts belonging to the University
of Leyden, to be correct to the tenth decimal
figure. The Arabians transmitted the new sys¬
tem ot notation to the flourishing colony of
their countrymen in Spain, whence it was slow¬
ly communicated to the several Christian States
over Europe. This change was effected chiefly
by the calendars or perpetual almanacs com¬
piled in the Moorish seminaries, and eagerly pur¬
chased by the various monasteries and convents
throughout Christendom. Yet the Arabic ciphers
appear to have remained unknown in every part
of Europe beyond Spain, before the middle of the
fourteenth century; nor in mercantile transac¬
tions were they commonly adopted till near two
centuries later. It is a singular circumstance
that the advantages of employing the descending
progression in the nicer calculations were not
sooner perceived, especially after the use which
Ptolemy had made of sexagesimals. Stevinus
was the first who distinctly introduced the prac¬
tice of decimal fractions in 1585, though Regio¬
montanus had made a great step towards that
improvement, which Ramus even indirectly em¬
ployed. To count downwards might seem as
easy as to reckon upwards. But the mode of
denoting the ranks of decimals was then most
cumbrous, the successive numerals, like the in¬
dices in Algebra, being inclosed in small circles.
Bayer in 1619 proposed to substitute for these
complex marks an accent repeated. It was our
illustrious countryman Napier, however, that
brought the notation of decimals to its ultimate
simplicity, having proposed in his Rhabdologia,
printed ten years earlier, to reject entirely the
marks placed over the fractions, and merely to
set a point at the end of the units. But his su¬
blime invention of Logarithms about this epoch
eclipsed every minor improvement, and as far
transcended the denary notation, as this had sur¬
passed the numeral system of the Greeks.
Various speculations have been framed re¬
garding the properties of the different arithme¬
tical scales. Leibnitz fancied important advan¬
tages to accrue from the adoption of the Binary
Scale, which operates with extreme facility, and
requires only a single character besides the zero.
This progression mounts so slowly, however,
that it cannot express a large number without
employing a multitude of terms. But the Duo¬
denary Notation, which is partially admitted in
the uncial subdivisions, would evidently answer
the best for general practice. It proceeds faster
than the Denary Scale, and is less subject to be
affected by fractions, since its root has no fewer
than four divisors, while few admits only of
two. Still these advantages would not compen¬
sate for its want of conformity with the train of
ordinary language. The Decimal Arithmetic
would soon generally supersede the use of every
other kind of fractions, if it were likewise in
practice combined with an extensive decimal
subdivision of weights and measures.
The curious or mystical properties of num¬
bers have at all times fixed the attention of
mankind. Square numbers, denoting the sides
of a right-angled triangle, were sought for by
the Pythagoreans, who gave a very simple rule
704
PRELIMINARY DISSERTATIONS.
to compute them.1 Perfect numbers, or such
as may be composed by the addition of their
aliquot parts, could not fail to excite admira¬
tion ; and Euclid produced an elegant theorem
for discovering them. It is remarkable that these
numbers should appear frequent at first in the
series, and afterwards occur only at wide inter¬
vals. Thus, below 10,000, there are four perfect
numbers; but the last of the succeeding four
includes no fewer than nineteen ciphers.2 The
moderns have advanced farther, and imagined
what are called Amicable numbers, on all which
subjects Euler has shown his ingenuity and un¬
rivalled analytical skill.
It is less a matter of speculation, while it is
of considerable consequence in the practice of
calculation, to assign the Prime Numbers, or
such as admit of no division, and to resolve the
Composite Numbers into their several factors.
No general method has yet been devised for the
investigation of Primes, though by the researches
of Bachet and Fermat in the seventeenth century,
and of Euler, Lagrange, Legendre, and Gauss, in
the eighteenth, they are now reduced to certain
constant forms, which may facilitate their dis¬
covery. By an extension of the method called
the Sieve of Eratosthenes, a sort of mechanical
process, the prime numbers are separated from
the ordinary progression. In this way several
authors have constructed tables of Primes, and
of Composite Numbers, with their various fac¬
tors or divisors. Lindenau proceeded to a hun¬
dred thousand, but Cherac has lately carried the
enumeration as high as ten millions.
The formation of Magic Squares, by which
the numbers in their natural order are disposed
in cells, so that each column gives an equal sum,
remounts to high antiquity. They have been
regarded in the east as charms or talismans, of
great potency in the tide of human affairs. The
digital squares from 3 to 9 were dedicated to
the seven stars, including the sun and moon,
which in the astrological visions were believed
to rule the successive days of the week.3 The
people of Siam had learned a very simple method
of filling up those squares; but some European
Mathematicians have since amused themselves
with such arithmetical curiosities. Stifels, in his
Arithmetica Integra, incidentally treated of Ma¬
gic Squares, yet without naming them. He was
immediately followed in a small arithmetical
treatise by Adam Riese; but the French seem
to have directed most attention to those scienti¬
fic recreations. From the latter part of the 17th
till beyond the middle of the 18th century, a
succession of ingenious persons were at pains to
improve and extend the construction. Frenicle,
Poignard, Delahire, Ons-en-Bray, and Rallier
des Ourmes, are entitled to particular notice.
The construction of Magic Squares belongs
to the class of problems styled Indeterminate,
which depend on variable combinations, and
therefore admit of very numerous answers.
Thus, Frenicle, who successfully studied this
subject near the beginning of the last century,
showed that the first sixteen of the natural num¬
bers could be formed into a Magic Square in not
fewer than 880 different ways. Analysts have
since tried to narrow those changes, and aug¬
ment the difficulty of the investigation, by an¬
nexing other conditions. Dr Franklin produ¬
ced, by dint of perseverance, what he called a
Magic Square of Squares, and a Magical Circle.
De la Hire4 treated the formation of Magic
Squares with such copious detail as to leave very
little to be done by his successors. Yet several
eminent mathematicians have occasionally re¬
verted to this amusing subject. Even the great
Euler has not disdained to direct his transcend-
ant skill in algebraic analysis to the solution of
1 See notes to the Elements of Geometry. Euler has demonstrated that every number whatever consists of not more than
four squares. An example may he given of the composition of numbers between 10 and 20: 10 = 9 + 1, 11 = 9 + 1 + 1,
12 = 9 + 1+ 1 + 1, 13 = 9 + 4, 14 = 9 + 4 + 1, 15 = 9 + 4 + 1 + 1,17 = 16 4- 1, 18 = 16 + 1 + 1,19 = 16 + 1 + 1 + 1,
20 = 16 + 4.
2 It may gratify the curious to see the series 6, 28, 496, 8128, 33550336, 8589869056, 137438691328, and
2305843008139952128. These numbers are obtained by multiplying the 1, 2, 4. 6, 12, 16, 18, and 30 powers of 2 by its
2, 3, 5, 7, 13, 17, 19, and 31 powers diminished by unit.
s The first in modern times who noticed Magic Squares was Agrippa of Nettesheim, who gave in his books de Occulta
Philosophia, printed in 1535, the Sigilla Jovis, Martis, Solis, Veneris, Mercurii, and Luna.
* Born at Paris in 1640, and died in 1718, a man of some attainments, and great application—well acquainted with the
details of surveying, and of practical astronomy.
DISSERTATION FIFTH.
705
problems connected with the theory of Magic
Squares.1 *
Another portion of Arithmetic, not merely
curious, but of material importance in the ap¬
plication of that science, has been much culti¬
vated during the eighteenth century. If both
the terms of a proper fraction be divided by the
numerator, there will result an equivalent frac¬
tion, having unit for its numerator, and an in¬
teger, conjoined with another fraction of smaller
terms, for its denominator. But' this new frac¬
tion may be again broken down in the same
way, and the process of decomposition renewed
successively, till a fraction with an integral de¬
nominator is at length obtained. This mode of
resolution is therefore the very same as what is
employed in finding a common measure or di¬
visor, only the several quotients are here pre¬
served. When the original fraction is expressed
by rational numbers, its decomposition must al¬
ways terminate; but if the numerator and de¬
nominator be mutually incommensurable, the
process of evolving their elements will never
draw to a conclusion. The fractions which
thence arise may simply repeat, or they may cir¬
culate at short intervals or periods, or they may
succeed each other without any sort of order
whatever. But it is evident that such progres¬
sive subdivision must approach constantly near¬
er to the true value, and that the resulting frac¬
tions, if successively recombined, will exhibit a
series of approximations.
The fractions of this kind were first noticed
by Lord Brounker,3 who proposed one of them
to express the ratio of the diameter to the cir¬
cumference of a circle, which Dr Wallis3 after¬
wards investigated. Huygens perceived the
utility of employing such fractions to represent
approximate ratios, and in this way he found
convenient small numbers to represent the teeth
of the wheels and pinions of his Planetarium.
But the subject appears to have lain neglected
till 1737, when Euler explored it with his usual
depth and felicity, in a distinct memoir publish¬
ed in the Petersburg Transactions. He may con¬
sequently be regarded as the real founder of the
Theory of Continued Fractions^ to which indeed
be gave the appellation they have since retained.
It was a favourite speculation of that great
analyst, who resumed the subject at different
times, and widely extended its application. Eu¬
ler showed how to convert any quadratic equa¬
tion into a Continued Fraction, and demon¬
strated that the expression for an irrational
square root consists of terms which either repeat
or circulate in regular periods. A cube root
may likewise be expressed by a Continued Frac¬
tion, but its terms can have no sort of order in
their sequence. As these Fractions, in approach¬
ing to their ultimate value, oscillate continually
between excess and defect, they are always
capable of being changed into Converging Series,
affected by the alternate signs of plus and minus,
and the transformation may be reversed. By this
method the very ingenious Lambert converted
the series of Gregory and Leibnitz for the length
of a quadrant into a Continued Fraction, whose
terms have a regular and incessant circulation,
and hence proved (what had only been presumed
before) that the Circle is incommensurable. But
he was enabled to proceed still farther, and to
establish, that even the square of the number
1 Cornelius Capito printed, in 1767, at Gliickstadt, a short treatise on Magic Squares, in which he proposed to vary
their construction no fewer than a million times. But the latest and completest work on this curious subject was compiled
by the late Professor Mollweide of Leipsic, the ingenious editor of KliigePs valuable Mathematisches Worterbuch.
a Born in 1620, and died in 1684; an able mathematician, but an unprincipled courtier.
3 This very remarkable man was born November 23, 1616, at Ashford in Kent—educated at Cambridge—became chaplain
to Lady Yere in 1643, and was then led to cultivate the art of deciphering, in which he acquired such skill, as to be after¬
wards frequently employed by the Long Parliament in examining intercepted dispatches. Through that interest he was ap¬
pointed to a sequestrated church in London, and chosen in 1644 one of the scribes to the Westminster Assembly of Divines.
But his austere occupation did not divert him from the nobler pursuits of philosophy and science ; and being appointed by
the Parliamentary commissioners in 1649, Savilian Professor of Geometry at Oxford, he continued regularly to discharge
the duties of that office.. He had afterwards some hot disputes with Hobbes, who, though a most ingenious metaphysician,
unfortunately mistook his own blunders for discoveries in Mathematics. Wallis maintained a large correspondence with
men of science, and assiduously contributed to the progress of philosophical discovery during that active period. The mo¬
deration of his character assured him the possession .of the places he held at the Restoration ; and though he found leisure
to compose a very learned philosophical grammar of the English language, and sometimes indulged his early taste for con¬
troversial divinity, he devoted the greater part of a long life to the laborious cultivation and extension of the various de¬
partments of Mathematical Science. His works are voluminous, and display great erudition, talents for deep research, and
criminality of conception. He died on the 28th October 1703, and was succeeded in the chair by Dr Hallev.
BISS. V 4 u
706
PRELIMINARY DISSERTATIONS.
expressing the circumference is likewise irra¬
tional.1
Lagrange has since recommended and ex¬
plained the application of Continued Fractions
to the solution of numerical equations. These
fractions may be readily changed into Recur¬
ring Series,2 which, in the case of small roots,
are often beautifully simple and remarkably con¬
vergent. But sometimes they betray the opposite
tendency to diverge; and the great object of
Langrange was to remove that defect. Euler, in
several of his last memoirs and opuscules, di¬
rected them to indeterminate problems, to the
finding of maxima and minima, and to the de¬
velopment and integration of certain analytical
formulae. Nothing can exceed the beauty of
some of these speculations.
It is a singular fact, that though Continued
Fractions had their origin in this island, they
were afterwards almost wholly overlooked by
our mathematicians. Scarcely thirty years have
passed away since the attention of the curious
was again recalled to them. But an acquaintance
with the transformation of those fractions would
prove extremely useful to practical men, by fur¬
nishing a variety of short approximations, which
are easily remembered and readily applied. Or¬
dinary computations in mensuration, in the com¬
parison of different weights and measures, and
in several standard proportions, might thus be
much abbreviated without any sensible inaccu¬
racy. The method proposed by Lambert for
decomposing fractions into progressions that
have their denominators formed by successive
multipliers, could be employed in a similar way;
but its application is somewhat difficult and in¬
tricate.3
To facilitate the operations of arithmetic,
tables have been digested of the powers and
products of numbers. The most astonishing
work of that kind, including all the multipliers
from one to one thousand, was produced by
Hervart, Chancellor of Bavaria, in 1610, only
four years before the invention of Logarithms,
the want of which it could in some faint degree
have supplied. But tables of products in a less
unwieldy shape are still occasionally used for
abridging the labour of calculation. A notable
improvement has been lately introduced by the
substitution of Quarter Squares, grounded on
the known property that the product of any two
numbers is equal to the fourth part of the ex¬
cess of the square of their sum above the square
of their difference. A single page might com¬
prise as many of those numbers as, by simple
addition and subtraction, would exhibit an ex¬
tent of products equal to those contained in
Hervart’s enormous folio.4
It would be a great improvement in elemen¬
tary education to introduce into the schools a
more extended multiplication table, including
at least all the products of the numbers from 1
to 25. A very useful practice has been adopted
lately in the north of Germany, to accustom
learners to the readiness of mental calcula¬
tion.5
1 The area of a circle having unit for its diameter is expressed by the alternating series 1 — h + l — } + i, &c. which
was converted by Euler into the continued fraction 1
T +
2+9^
¥ + 25
¥ + 49
2 + &c., the numerators being the squares
of the odd numbers. This extension never stops, and consequently the fraction is not reducible to finite terms, the
square of the expression runs into a similar infinitude. _
2 It deserves to be mentioned that Girard first gave the simple recurring series which expresses the parts of a line di¬
vided into extreme and mean ratio. It is formed by the continued addition of the two preceding terms. Ihus 0, 1, 1, 2,
3, 5, 8, 13, 21, 34, 55, 89, 144, &c. The square of each number in this series differs from the product of the two numbers
which inclose it, only by unit alternately in excess and defect: Thus 82 = 64 = 5 x 13 — 1, 132 = 169 = 8 x 21 + 1.
3 For an explication of Lambert’s method of decomposing fractions, see Philosophy of Arithmetic.^
* A large table of multiplication, from 1 to 10,000, and a specimen of quarter squares, extending to a million, may be
seen in the treatise quoted above. _ _ • xr
s It is called Kopfrechnung or calculating by the head. Three works are current on this subject, those of Biermann, Heuss,
and Kohler—published between 1790 and 1816.
DISSERTATION FIFTH.
707
3. ALGEBRA.
Algebra derives its immense superiority over
the ancient analysis from the very complete sys¬
tem of notation which it has at length attained.
Each step of an investigation being now regis¬
tered in the clearest and most precise manner,
the mind is relieved from the fatigue of carrying
forward the whole of a continuous chain of rea¬
soning. It can rest at any placed and again re¬
sume the process of deduction with the greatest
facility. But this perfection of pictured lan¬
guage has been the result of a series of slow
and successive improvements. Diophantus, who,
soon after the Christian era, composed a large
treatise on the resolution of certain arithmetical
problems, a portion of which work is preserved,
made the first attempt towards an abbreviated
form of analysis. The symbols he used were,
however, exceedingly few, being the initials or
terminations of the ordinary words, only some¬
what modified. It deserves remark, that Dio¬
phantus viewing a number as composed from
another by the addition or subtraction of a
third, he termed this last one abundant or de¬
ficient, and gave a rule for the multiplication
of those affected numbers, similar to what is
now applied to the signs plus and minus. His
treatise passed into the hands of the Arabians,
who studied the numerical properties with much
ardour, hut made no advances in refining or
simplifying the form of notation. From them
again this higher species of arithmetic was
transplanted into Italy, probably during the
fourteenth century, by Leonard, a merchant
of Pisa, who had travelled long in the East.
A series of works on Arithmetic and Geome¬
try were published between the years 1470
and 1487 by Pacciolo, a Minorite Friar, who
in 1494 brought out his Arte Maygiore, or what
he says was vulgarly called the Ilegola de la
Cosa, or Alghebra and Almucabala. the first ap¬
pellation derived from the Italian Cosa, denot¬
ing the Thing sought, and the other borrowed
from the Arabic words expressing Resolution and
Composition. After the appearance of this ele¬
mentary digest, Algebra was cultivated in Italy,
during the first half of the sixteenth century,
with great industry and success. Ferreo, Tar-
talea, and especially Cardan, made rapid ad¬
vances in the new science. This ingenious
though very singular person not only gave the
solution of Cubic Equations which hears his
name, but discovered the leading properties of
equations in general, distinguishing their roots
into the true and the fictitious ; and besides im¬
proved the notation by employing frequently the
letters of the alphabet. The Italians, however,
still used contracted words for symbols, and
the initials p. and m. for the signs of plus and
minus. In 1572, Bombelli of Bologna, retaining
this embarrassed mode of writing, composed a
regular summary of Algebra, which he enriched
with Ferrari’s rule for resolving biquadratic
equations. In the meanwhile the knowledge of
the analytic art had penetrated into Germany,
where it received its capital improvement in no¬
tation from the systematic genius of that people.
The change was chiefly effected by the industry
of Stifels,1 a Protestant minister and zealous
follower of Luther, who in 1544 published his
Arithmetica Integra. In that remarkable work
he first introduced the symbols -f and — for
plus and minus, and the character A (or a con¬
tracted R) for Radix or root; and he repre¬
sented unknown quantities by the capital let¬
ters A, B, C, &c. and intimated the successive
powers and their reciprocals by an ascending
and descending series of exponents. Nor was
his merit confined to algebraic writing: the en-
1 Born at Eslingen, in Saxony, in 1509, and died at Jena in 1567- Though a profound and inventive mathematician,
he seems to have imbibed all the wild enthusiasm of that convulsed period. Captivated perhaps by the wonderful properties
of numbers, he fancied, as other ingenious persons have since done, that he could interpret the visions of the Apocalypse,
and foretell the end of the world. He was so imprudent as to place that awful dissolution very near hand. Early in the
morning of the day predicted in the year 1553, he assembled his trembling flock in a wide open field, where he endeavoured
to season their minds for the tremendous change by fervid prayers and pathetic exhortations. The sky was lowering, the
darkness thickened, a portentous silence prevailed, and the preacher rolled his thunders with overpowering energy. But
the.clouds soon passed away, the sun shone forth in his wonted splendour, and all nature smiled. The populace recovered
their agitated spirits; and now breathing rage and disdain, they chased the unlucky prophet home with volleys of stones.
708
PRELIMINARY DISSERTATIONS.
tlmsiasm of the age seems to have roused the
spirit of invention in him; and Stifels anti¬
cipated some of the later discoveries, pointed
out the nature of Logarithms, explained the pro¬
perties of figurate numbers, and showed how
the co-efficients of the powers of a binomial
quantity may be derived from the columns of
what has been since called the arithmetical tri¬
angle. Scheubel a few years afterwards pursued
the same path, yet without adding any thing
material to the science. In this state it made its
way at last into England, where Recordej1 an
ingenious though unfortunate man, printed the
Cossic Art at London in 1553. He was the
first to propose the sign = for equality, but
made no other advances; and during a period
of most active enterprise, till the close of the
century, Algebra was not cultivated at all in this
country.
In the meanwhile France continued the pur¬
suit of the mathematical sciences. Ramus had
revived those abstract studies; but Vieta, who
succeeded him, and flourished between the years
1570 and 1600, rose by his numerous discoveries
to much higher eminence; a lawyer by pro¬
fession, yet a man of great learning, and gifted
with profound and original genius, conjoined
with the most indefatigable application. Yieta
introduced the literal or specious Algebra, and
thus rendered its procedure quite general, by
employing the Roman capitals always to denote
numbers, the vowels being appropriated to un¬
known quantities. He likewise traced vari¬
ous distinctions, and framed several significant
terms, which are still retained. But while he
improved the analytical symbols, he greatly ex¬
tended the theory of equations, and cultivated
with success the prolific and important subject
of angular sections.
Flanders at this period equally displayed the
spirit of invention. Stevin of Bruges, born
about the middle of the sixteenth century, was
an engineer eminently skilled both in the theory
and practice of his profession, possessing great
original powers of mind. He reduced Statics
and Hydrostatics to their simplest principles;
and in his Arithmetic or Algebra, printed in
1585, he extended the range of calculation by
several fine improvements and discoveries.
Marking the unknown quantity with a small
circle, he denoted its power by inserting the in¬
dex ; and was enabled, by prefixing a fraction,
to represent also the roots. But, besides improv¬
ing and simplifying the symbols, he enriched
the analytic art by his inventions, and gave a
general method for the resolution of numerical
equations. The works of Stevin were, in 1625,
collected and expanded by his countryman Gi¬
rard,2 a man likewise of most original concep¬
tion, who eagerly promoted the objects of science.
Four years afterwards this editor produced a
small tract exclusively his own, and full of new
and ingenious deductions. He there gave a very
complete theory of equations, distinguishing
them into their several orders, and proving that
they had always a corresponding number of
roots; he showed how these roots are succes¬
sively combined in forming the co-efficients of
the several terms; and finally anticipated the
remarkable rule discovered by Newton, to find
the sums of their different powers. Girard was
possessed of fancy as well as invention; and his
fondness for philological speculation led him to
frame new terms, and to adopt certain modes of
expression which are not always strictly logical.
Though he stated well the contrast of the signs
plus and minus, in reference to mere geometrical
position, he first introduced the very inaccurate
phrases of greater and less than nothing, and began
the unfortunate appellation of impossible quan¬
tities.
It is indeed the reproach of modern analysis
to be clothed in such loose and figurative lan¬
guage, which has created mysticism, paradox,
and misconception. The Algebraist, confident
in the accuracy of his results, whenever they
1 Itobert Recorde, born of a good family in Wales, about the year 1506—studied at Oxford, and elected a fellow there in
1531. He embraced the medical profession, but taught mathematics at both universities, and afterwards in London, where
between the years 1551 and 1557 he published several elementary treatises on Geometry and Algebra, with quaint titles
But Itecorde was unfortunate, and having been thrown into the Fleet for debt, he died a prisoner in 1558.
2 Albert Girard published his edition of Stevin’s Arithmetic in 1625, and his own discoveries in Algebra in a small
quarto at Amsterdam in 1629. He died in 1633, and his widow the year after put forth his complete collection of Stevin s
works.
DISSERTATION FIFTH.
709
become significant^ hastens through the suc¬
cessive steps to a conclusion, without stopping
to mark the conditions and restrictions impli¬
cated in the problem. This rapidity of opera¬
tion, though in many respects most advanta"
geous, yet affords less mental exercise than the
cautious and guarded procedure of the Greeks.
It will not he deemed foreign to the scope of this
discourse, to remark, that the signs p/ws and minus
confer no distinctive character, hut merely in¬
dicate that the number to which they are pre¬
fixed, is to he annexed to some other number,
or disjoined from it. The terms additive and
subtractive would express correctly their whole
import. The rules for the involution of those
signs are derived from the consideration of the
properties of compounds, arising from the addi¬
tion or multiplication, for instance, of the bino¬
mials a^b andc^= d. The operation proceeds
by detail; but the real meaning of the notation
may be suspended, and it becomes significant
only after the several members have been recom¬
bined. A number, in strict language, is alto¬
gether devoid of quality, and can be reckoned
neither positive or affirmative, nor negative, which
designations are accidents, and not attributes.1 In
proposing these terms, Vieta did not, therefore,
discriminate the precise nature of the symbols;
and his powerful example has continued to in¬
fect the language and darken the conceptions
of algebraists. A disposition has also prevailed
in modern times, of hastening to general con¬
clusions, although the data be limited or imper¬
fect. Such careless deductions are but awkward¬
ly amended, by the adoption of expedients more
like the fictions of lawyers than the reasonings
of sound logicians. The introduction of equal
and impossible roots of equations served only
to restrict the ordinary rules, which had been
made too general, representing the number of
roots as always equal to the index of the highest
power. The involution or repeated multiplica¬
tion of binomials will produce the successive
orders of expressions, which pass into equations
on the supposition that any one of them vanishes
or has its parti mutually balanced. But the con¬
verse of this proposition will not always hold
true, That every compound expression is re¬
solvable into as many binomial factors as the
index of its highest power signifies. Several forms
even of the quadratic or cubic expressions resist
all binomial decomposition. But it is a property
demonstrated, that every higher expression what¬
ever may be resolved into binomial or trinomial
factors, or into simple or quadratic elements. Im¬
possible quantities are thus merely the symbolical
exhibition of the binomial factors of a quadratic
or trinomial expression which is irreducible; and
1 This distinction might perhaps have satisfied the scruples of the late venerable Baron Maseres, who wrote an express
treatise against the abuse of the Negative Sign, which he came to view with a sort of aversion as the main source of the incor¬
rect language and vague conception so prevalent among algebraists. Though not quite entitled to the rank of a discoverer,
that excellent person deserves a place in the history of Mathematics, for his valuable contributions, and his zealous and un¬
wearied exertions to promote accurate science. He was an able geometer, a profound constitutional lawyer, a man of
sound and most extensive learning, and of very general information. But he possessed the higher qualities of our nature,
and combined liberality of sentiment and unbending integrity with the feelings of a kind, generous, and social disposition.
His Elements of Trigonometry was the completes! treatise in English at the period of its appearance. He afterwards im¬
proved the solutions of cubic and biquadratic equations, and illustrated the methods of approximating to the resolution of
equations in general. But the most important service he rendered to mathematical science consists in reprinting at great
expence, and chiefly for distribution, the series of original authors in logarithms, with ample annotations, in six large
quarto volumes. From his anxiety to be perspicuous, he was apt to fall into the opposite extreme of tiresome prolixity.'
The grandfather of Maseres was an officer in the French guards, born in the district of Bearn, and a Hugonot, who, on
the revocation of the Edict of Nantes, retired to Holland, and transferring his services to the Prince of Orange, accompa¬
nied the Preserver of our liberties into England, and fought by his side in Ireland. The grandson having embraced the
profession of the law, was soon after the peace of 1763, probably on account of his intimate acquaintance with French lan¬
guage and customs, appointed Attorney General of Quebec, where he resided till 1770. At leaving his charge, he visited
Boston and New York, while that agitation was fermenting which burst into open revolt. Soon after his return to Eng¬
land, he published in successive volumes his Canadian Free/iolder, in which he refuted the despotic maxims of Lord Mans¬
field, and earnestly recommended conciliatory measures with our American colonies. But it was a time of infatuation and
disaster. Maseres by his firmness gave mortal offence to the courtiers, and never obtained any promotion, farther than
the small sinecure office of Cursitor Baron of Exchequer. But fortune had abundantly provided for all his wants, and he
enjoyed unbroken health, and the renovating pleasures of study and social intercourse. The Baron had composed a full
and learned treatise on Life Annuities, and matured a plan for securing small pensions from Government to such of the
poorer classes as should make certain contributions during the vigour of their days. This he embodied in a Bill which
passed the Commons, but was lost in the House of Lords, through the influence of the Bishops, who seem to have consi¬
dered pauperism as a right appendage to their splendid ecclesiastic establishment. He died at Iteigate in May 1824,
at the very advanced age of 93.
710
PRELIMINARY DISSERTATIONS.
the mark of impossibility is removed, either by a
change of the signs, or by a recombination that
restores those factors to their primitive bino¬
mial form. Such notation may indicate the li¬
mits of a problem, and seems to originate in
neglecting the previous statement of the limita¬
tions. 1 In reference to Geometry, the impossi¬
ble expressions intimate the transition of the
circle into the equilateral hyperbola, or of arcs
into logarithms.
The publication of the Geometry of Descartes
in 1637 is justly deemed an epoch in the his¬
tory of analytical science. The capacious mind
of the author seized on all the preceding disco¬
veries, and moulded them with his original in¬
ventions into a regular and comprehensive sys¬
tem. He gave rapidity to the writing of Al¬
gebra by the introduction of small characters,
and rendered the distinction more palpable be¬
tween known and unknown quantities, by the
appropriation of the initial and final letters
of the alphabet. He adopted the notation of
the integral exponents or indices, as reduced to
its simplest form by Herigon; and this appa¬
rently very slight improvement led, in the se¬
quel, to the most important results. Though
the index was at first merely a contraction for
the repeating of the same letter in the involution
of powers, yet it acquired a most extensive im¬
port when it came to be treated abstractly as a
number. The prefixing of the subtractive sign
changed the expression into its reciprocal, and
the substituting of a fraction converted it into
the symbol of evolution or the extraction of
roots. Nothing can better illustrate the effi¬
ciency of a systematic notation, as an instru¬
ment for enabling the intellect to pursue and
generalize its deductions, than the successive
modifications which analogy suggested in the
marking of exponents, during the short period
from Descartes to Newton.
But the French philosopher effected a revolu¬
tion in scientific procedure, by applying (what
his countryman Yieta had only partially at¬
tempted before) the symbols and calculations of
Algebra to the solution of geometrical problems.
By referring curve lines to co-ordinates or mu¬
tual perpendiculars, he expressed their relations
by equations, of which he distinguished the rank
and composition. He showed that a biquad¬
ratic equation is, by the help of indeterminate
co-efficients, resolved into two quadratics, and
may be constructed by combining a circle with
a conic section. The construction of a cubic
equation was somewhat simpler, though derived
from the same principles. But Descartes pro¬
ceeded still farther, and represented what are
now called curves of double curvature, by re¬
ducing them, by a series of perpendiculars, to
some plane of projection. These were all im¬
portant advances in mathematical speculation.
Attempts have been made to apply the Car¬
tesian method even to Elementary Geometry,
which is in fact to convert a clear and simple
train of reasoning into a sort of hard mechanical
process of calculation. This change, were it at¬
tainable, would be the reverse of an improve¬
ment. It would extinguish that fine study which
affords the best exercise and discipline of the in¬
tellectual powers. The wonderful dexterity and
readiness which men of such teeming invention
as the Bernoullis, Euler, and Lagrange gene¬
rally displayed in managing algebraic analysis,
appear to have seduced their admirers into an
over-estimate of its real advantages. The con¬
structions derivedfrom algebra very seldom reach
the purity and elegant simplicity of the geome¬
trical methods. In those cases where Geometry
1 A very simple problem will illustrate this: Suppose it were required, from a given point, to draw a tangent to a
given circle. The construction would be, to join the centre with the given point, and upon the connecting line describe
a circle to cut the former m the points of contact. It is evident, that if the given point occupied the extremity of the
diameter, there would be only one point of contact; and if it lay within the circle, there could be none. This construc¬
tion hence intimates sufficiently the conditions of the problem; and yet it fails in the case where the circle described
merges in the given point, and consequently ceases to determine the position of the tangent. The algebraical solution,
if rightly interpreted, gives similar information. Let r denote the radius of the given circle, and a the distance from
its centre to the given point; then \J a* — r2 will express the length of the tangent, which only requires to be inflected
to the given circumference. But if the given point fall on that circumference, then a = r and the origin and termination
of the tangent coincide, leaving its position undetermined. Again, if the given point lie within the circle, a will be less than
r, and consequently the subtractive portion — r2 will predominate over the other portion a2, and the compound radical
Vo2 r2 become impossible. It serves to show, however, that by a change of condition the problem would be rendered
soluble.
DISSERTATION FIFTH.
711
is most felicitous, they betray the features of a
clumsy and artificial combination. The applica¬
tion of Algebra should therefore be reserved for
the most arduous and complicated problems in
the Higher Geometry.
In the latter part of the seventeenth, and du¬
ring the course of the eighteenth century, Al¬
gebra still continued to advance; and though it
underwent no revolution, it acquired greater
perfection in all its details. The construction
of cubic and biquadratic equations, which Des¬
cartes had effected by combining a circle with a
parabola, was afterwards improved; but Newton
proposed the Conchoid as the curve best adapted
for the practical solution of such problems.
Leibnitz succeeded in conquering the irreducible
case of Cardan, by a bold application of the bi¬
nomial theorem, having converted the cubic
roots of the compound expressions into two se¬
ries, with alternate imaginary terms, which are
extinguished by their conjunction. In examin¬
ing generally the nature of cubic equations, their
solution came afterwards to be referred to the
trisection of a Circular or Hyperbolic Sector, and
was therefore accomplished by the application
of a table either of Sines or of Logarithms. The
theory of the Section of Angles and of Ratios,
founded by the ingenuity of Cotes, furnished a
clue to the resolution of certain forms of the
Higher Equations. But though Euler solved
biquadratics in a different way from that of
Descartes, all attempts to find directly the roots
of tbe fifth and the superior orders of equations
had totally failed. It became necessary therefore
to have recourse to the approximative methods
of resolving equations. Successive improve¬
ments in the process of calculation were made
by Raphson, Halley, Lagny, and Taylor; so
that little seemed wanting for any practical end.
During the last century likewise the method
of series, so various and extensive in its applica¬
tion, was cultivated with the greatest success.
About the years 1714 and 1718, Montmort1 and
James Bernoulli employed it in the investiga¬
tion of the Laws of Chance. But De Moivre,2 a
French refugee, and a man of learning and pro¬
found science, carried these researches much
farther, having devoted his time professionally
to the calculation .of probabilities, and of the
values of life-annuities. In 1730, he published
an original work, which, besides other useful in¬
ventions, explained the properties of a Recurring
Series, that always repeats the same succession
of co-efficients in distinct sequences. About
the same time, Stirling3 brought out a complete
treatise on Series, in which he advanced by a
different road to consider their convergence, in¬
terpolation, and summation. This ingenious
1 A man of some rank, and an able mathematician, born in 1678 at Paris, where he died in 1719.
2 Abraham De Moivre, born in 1667 at Vitri in Champagne. Being a Protestant, he was obliged at the age of eighteen
to seek shelter in England after the revocation of the Edict of Nantes. Having shown an early taste for Mathematics, he
continued to prosecute the study as a profession. He supported himself creditably in exile, by giving lessons and reading
public lectures. His analytical discoveries extended his fame, and his good conduct insured him respect. He embraced
the Newtonian Philosophy, and made some improvements on it. He generalized Cotes’ famous theorem of the section of
a circle, but turned his attention chiefly to the method of series, which he applied successfully to the doctrine of annuities
and chances. After his reputation for such calculations had been established, it is said that he spent a great part of the
day at Slaughter’s Coffee-House, in St Martin’s Lane, where he was ready to answer any question of "that nature pro¬
pounded to him, for the fee of one guinea. His principal work on the Doctrine of Chances was published in 1738, but the en¬
larged and improved edition bears date 1756. De Moivre lived to a great age, but in his advanced years he was subject to
obstinate fits of sleeping, and in that torpid state he remained for at least several weeks, till death closed the scene in
November 1754.
3 James Stirling, born about the year 1690 in Stirlingshire, where his father owned a small property. He was educated
at Glasgow, and sent by that University on Snell’s Foundation to Baliol College in Oxford. During his retreat there
he applied himself so diligently to the study of Mathematics, that he printed in 1717 a small tract on Lines of the Third
Order, with new solutions of one or two difficult problems by the fluxionary calculus. He then repaired to London, and
becoming acquainted with the Venetian Minister, he accepted an invitation to settle at Venice, where he resided several
years, and taught Mathematics. The vicinity of Padua gave him an opportunity of acquiring the friendship of Nicholas Ber¬
noulli, nephew of the two elder Bernoullis, who was Mathematical professor in that University. During his stay at Venice,
Stirling contrived to gam access to the manufacture of glass plates, and escaping at some personal risk, he is said to have
transferred the secret to England. He now conducted a mathematical or nautical school on Tower Hill, while he maintained
a correspondence with the philosophers both abroad and at home. Here he published his great work on the Differential Me.
thod and Series in 1730. After toiling in his academy several years, he was induced to leave London, and undertake the
direction of the Mines at Leadhills in Scotland. In that elevated district near Sanquhar he resided during the rest of
his life, and by his skill and activity he greatly improved the operations of extracting the lead ore. He now held a profitable
employment, but his high mathematical fame would have secured him the honour of succeeding Maclaurinin 1746, if he had
not at that unhappy period been tainted with Jacobite principles. In his latter years he seems to have confined his attention
to practical concerns, and died at Leadhills in 1772-
712
preliminary dissertations.
mathematician followed no general procedure,
but showed great felicity and address in trans¬
forming one series into another. The subject
was at different times partially extended by
Simpson, Maclaurin, Landen, Lorgna, Hutton,
Waring, Pfaff, and Kramp. Euler handled Se¬
ries with his usual fulness, perspicuity, and pe¬
netration ; and yet Lagrange and Laplace, in
surveying that field, have gleaned fresh disco¬
veries, which the latter of these illustrious men
applied most happily to develope the Theory of
Probabilities.
The composition of equations was at the same
time investigated with more address and preci¬
sion. The rule for distinguishing the positive
and negative roots from the alternating signs,
which Descartes had merely stated, now received
a strict demonstration by Segner. The mode
of finding the impossible roots, or rather the
quadratic factors, of an equation, which Newton
probably had inferred from mere induction, was
traced by Maclaurin to its real source. D’Alem¬
bert proved that every irrational expression is
reducible to the form Ae =±: V — B2; or, in other
words, that every compound expression of a
higher order may he resolved either into simple
or quadratic factors. This is the most impoit-
ant conclusion perhaps relating to the nature of
equations. But the general theory was never
so clearly and completely discussed as by Gauss,
in a small work published by him in 1779.
Various methods, and several of them elegant,
have been proposed by Euler and others for
simplifying and expediting the approximation
to the roots of equations. When a question in¬
volved the powers and products of more than
one unknown quantity, it exercised the skill of
algebraists to separate them; but Bezout1 has
brought the mode of this elimination into a
regular system, which removes all the difficul¬
ties. Among the promoters of Algebraical
Science may he ranked our countryman Dr
Waring,2 a profound analyst, hut unfortunately
an obscure and confused writer. His Miscel¬
lanea Analytica and other detached pieces dis¬
cover uncommon penetration and originality of
conception, and though neglected at home, they
have, notwithstanding their repulsive form, been
duly appreciated by the great mathematicians
on the Continent.
The latest improvement that Algebra has
received consists in the Combinatovial Analysis^
which may he viewed as an important extension
of the principles of the binomial theorem. Vieta
traced the rudiments of the doctrine, which was
successively enlarged by Mersenne, Guldinus,
Schooten, Pascal, Wallis, James Bernoulli,
De Moivre, and Euler. But it has received its
greatest expansion in Germany, and chiefly
from the laborious and persevering researches
of Hindenburg, who first published a tract on
this subject in 1779, and resumed the discussion
in the years 1793, 1794, and 1795. He was
followed in the same line of investigation by
Burckhardt, Rothe, De Prassi, and Pfaff; and
this interesting branch of analysis now forms a
part of the algebraical course pursued in the Ger¬
man States. It throws much light on the theory
of equations, renders more general the method of
series, and facilitates the calculation of chances.
In the application of Algebra to Geometry,
Euler, pursuing the route marked out in 1727
by Frederick Mayer, has given such extension
to the properties of Angular Sections, as to cre¬
ate almost a new science, bearing the appellation
of the Arithmetic of Series. Vieta prepared the
1 Stephen Bezout, born at Nemours on the 31st March 1730—led accidentally to ^n° IV^thmnatfcal3 Science^
>y the perusal of the Eloges of Fontenelle. Having soon distinguished himself by proficiency in hi;
le was appointed Examiner to the Navy in 1763, and Examiner ot the Artillery Depart 7 • „ ^
luty in those offices, he gained the love and respect of the youth by his impartiality, kinJn^s> ^d soliatude fo^he ^
rancement. He published The General Theory of Equations in 1779, and gave further proofs of his original inventive p
n other occasional Memoirs. But he has owed his celebrity chiefly to the excellent Course of compiled for
irofessional education, which is highly esteemed and generally adopted on the Continent. The cons i u 10
irematurely exhausted, and he died of a malignant fever on the 27th of September 1703. , . mud,
2 Edward Waring, born near Shrewsbury in 1736. He studied at Cambridge, where he distinguis ei . .-gQ
n abstruse calculations, that he was elected, after a hard contest, Lucasian professor of Mathematics ^ J—y 1760.
He led the life of a recluse student, and though a man of great worth, he was unfitted by his extreme . ,
general intercourse of society. His latter years appear to have been spent at lns_ place ot nativity, w lere
15th August 1798. Waring had not entirely confined his application to mathematical research ; he pnn e . H^trnetlv
tract of considerable merit, which was distributed among his friends; and it deserves mention, that re le
brought forward the philosophical view of Causation which is now very generally embraced.
DISSERTATION FIFTH.
713
way, and the Bernoullis had advanced far in the
research, but it was reserved for their great dis¬
ciple to expand and convert their conclusions
into a compact body of doctrine. This im¬
portant branch of Analysis has continued to
he much cultivated in Germany, under the
more expressive name of Goniometry, which was
first applied by Lagny in the Parisian Transac¬
tions for 1724, to an ingenious method proposed
by him for measuring angles.1 Pfaff has lately
enlarged it with the properties of the multiple
tangents, and his countryman Mollweide has
likewise made some valuable additions. The
store of formula now collected is of the utmost
utility in transforming and reducing into prac¬
tical operation the different series adopted by
Physical Astronomy.*
Algebra has also been applied with advantage to
Goniometry generally, as comprehending the so-
1 ution of the cases both in Plane and Spherical Tri¬
gonometry. This was early attempted by Girard,
but carried to its completion by Euler and La¬
grange. Some concise and elegant formulae have
been deduced, which facilitate and diversify the
practice of computation. In short, if Algebra
were purged of the vitious language and inaccu¬
rate conceptions that pervade it, and which were
early introduced by the confidence of rapid and
careless calculators, it might at last claim the
character of a perfect science.
The number of elementary treatises of Algebra
which have been produced in various languages
during the currency of the eighteenth century,
appears quite incredible. They are almost ephe¬
meral, and assume every feature and dimension,
superficial or profound, from the size of a primer
to the magnitude of a lexicon. A very few of
those works claim the highest praise, and may
retain their hold of education. The Algebra
of Euler is in various respects a most remark¬
able production. That illustrious analyst, when
totally deprived of sight in his advanced age,
dictated it in the German language to a young
domestic, whom he trained for an amanuensis.
He was obliged therefore to he plain, distinct,
and perspicuous; and these qualities he com¬
bined with richness of invention. The second
volume had an air of originality, which made
it peculiarly interesting. It treated of Diophan-
tine Problems, and the resolution of Indetermin¬
ate Equations,2 3 and was afterwards expanded in
the French version by the masterly annotations
of Lagrange. In our own language, Maclau-
rin’s Elements of Algebra, though a posthumous
work, is perhaps the ablest on the whole, and
the most complete. The bulky volumes of Dr
Sanderson,4 which were likewise printed after
the death of the author, are commendable chief¬
ly as the production of an ingenious person,
afflicted from infancy with the calamity of total
blindness; they have little claims to depth, ori¬
ginality, or logical precision, but possess the
merit of being eminently clear, methodical, and
copious even to diffusion. The Algebra of
Thomas Simpson is a work of an opposite de¬
scription—brief, condensed, and marked with
traits of invention. Passing over the numerous
smaller treatises which have run through the
schools, the compilation of Emerson3 deserves
notice. It forms part of the Cyclomathesis, or
1 This consists in performing by the help of compasses a repeated decomposition, similar to what is effected in the re¬
duction of a common to a continued fraction. There being in practice generally a balance of errors, the numerical relation
hence derived approximates to great precision. The method may be applied to the comparison either of arcs or of straight
2 The collection of formulae by Hirsch deserves particular commendation.
3 A very simple and regular method of solving such questions is given in the second volume of the Transactions of the.
Royal Society of Edinburgh.
4 Nicholas Sanderson, born at Thurleston in Yorkshire in 1682. When only twelve months old, he lost both eye¬
balls by small-pox ; but showing early capacity, he was sent to the free-school at Penniston, where he made great profi¬
ciency in the knowledge'of the classics, and soon understood the works of the ancient Geometers when read to hirn in the ori¬
ginal Greek. He afterwards profited by the kind instructions of some mathematical friends, and found himself so far ad¬
vanced in science, that at the age of 25 he repaired to Cambridge, and established his fame in that university bv the
warmth and splendour of his lectures on the Newtonian Philosophy. He was encouraged by the gentleness of Whiston,
who saw no rival; and, on the ejection of that amiable enthusiast in 1711 for heresy or dogmatism, succeeded to the Lu¬
casian Professorship of Mathematics, the duties of which he continued henceforth to perform with zeal and assiduity. The
faculties of touch and hearing he possessed in a wonderful degree ; and he was a lively companion, breathing a free and
open disposition. But sedentary habits impaired his vigorous constitution, and he died of a mortification in his limbs on
the 19th of April 1739.
. s William Emerson, born in June 1701 at Hurworth, a village near Darlington—the son of a schoolmaster, who taught
him Mathematics, and left him a small property, which he occupied and cultivated. He was a person of strong intellect
D1SS. V. a v
714
PRELIMINARY DISSERTATIONS.
series of elementary works in all tlie depart¬
ments of Mathematics and Mechanical Philoso¬
phy, executed with ability by that singular man;
exhibiting a mass of valuable matter, clothed in
a slovenly stvle, and digested without method,
or any regard to taste or elegance. Nothing is
more wanted for the purpose of education than
a classical treatise on Algebra, which, avoiding
all vague terms and hasty analogies, should un¬
fold the principles with simplicity and rigid
accuracy, and follow the train of induction with
close and philosophical circumspection.
4. THE HIGHER CALCULUS.
Leibnitz, at his death,left the Calculus which
he had framed in a most flourishing condition.
The superiority of its algorithm, joined to the
ardour of his disciples and successors the Ber-
noullis, gave it the complete possession of the
Continent. But in England, the Method of
Fluxions, now greatly in arrear, was cultivated
only by a very few aspirants. Its inventor had
vacillated about the notation he should adopt, and
the unfortunate marking by points appeared the
first time in one of the volumes of Dr Wallis’
works, printed in 1699.1 Newton had published
nothing separately on the subject, till the Tract on
Fluxions, drawn from the recesses of his closet,
made its appearance in 1704; which, though
full of ingenuity, was then decidedly imperfect
and insufficient. But Cotes* and Taylor3 labour¬
ed successfully in extending the analytical dis¬
coveries of their great master. The former, one
of the brightest mathematicians whom England
has produced, died at an early age, after achiev¬
ing, however, some fine analytical discoveries.
Besides producing the beautiful geometrical theo¬
rem on which is founded the application of Bino¬
mial Factors, he constructed an ample Table of
Fluents or Integrals, which were solved by the
decomposition of fractions, by Logarithms or
Circular Arcs. Other ingenious problems are in¬
troduced in his posthumous volume entitled i7ar-
monia Mensurarum, published in 1722 by his rela¬
tive and successor Dr Smith; but for want of
the author’s revision, this profound tract is un¬
luckily so concise and obscure as to need a com¬
mentary. Some of the propositions were neat¬
ly demonstrated by John Bernoulli; but De
Moivre considerably extended the doctrine, which
was afterwards reduced into a systematic form
by Walmesley.
Dr Brook Taylor was a man of rich invention
and elegant accomplishments, who supported
with dignity the reputation of English science.
He was indeed out only mathematician that,
and considerable talent of invention; but affected singularity, and indulged coarse boorish habits. Having a mechanical
turn, he constructed his own instruments, and delineated all the figures he wanted. His best work, perhaps, was the trea¬
tise of Increments, but his System of Mechanics has had the greatest currency among all ranks of students. In the de¬
cline of life he suffered much from the cruel attacks of gravel, and died after a lingering illness on the 20th May 1782..
1 The earliest mode used by Newton for denoting a Fluxion seems to have been a zero prefixed to the variable quantity.
Thus, the fluxion of was written n x*1— 1 ox. It is evident therefore that the great inventor must have then had nearly
the same conception of the origin of Infinitesimals as his rival Leibnitz.
2 Roger Cotes, born July 10, 1682, at Burbach in Leicestershire, of which his father was rector. Having shown an
early and decided inclination to Mathematics, he was encouraged by his uncle, the Rev. John Smith, who carried the boy
to his house in Lincolnshire, and carefully instructed him in the principles of science. Hence he removed to St Paul’s
school, where he made great progress in classical attainments, but still found leisure to cultivate his favourite studies.
Thus accomplished, he was sent to Trinity College at Cambridge, and advanced through all the gradations with unrivalled
distinction. In January 1706, he was elected unanimously to the chair of Astronomy and Experimental Philosophy,
which had been just founded by Archdeacon Plume. He took orders in 1713, and at the desire of Dr Bentley superin¬
tended the printing of the second edition of the Principia, to which he furnished a learned and ingenious preface. His
genius and uncommon talents had raised the highest expectations, when a putrid fever snatched him away in the full tide
of vigour, on the 5th of June 1716. Newton in his latter days used often to exclaim with a modest feeling of regret, “ If Cotes
had lived we should have known something.” This very promising philosopher was perhaps rather fastidious; for, except a
short but ingenious essay on Logarithms, he produced nothing of decided importance during his lifetime. The papers left
by him in an imperfect and unfinished state were collected and published with some annotations by his cousin and succes¬
sor Dr Robert Smith.
3 Born in affluent circumstances at Edmonton in Middlesex in 1685; studied at Cambridge, where he distinguished
himself, and passed through the successive gradations with the greatest applause. The mathematical and physical sciences
were his favourite pursuits, but he embraced general learning and cultivated the fine arts, being especially fond of paint¬
ing and music. Fortune enabled him to indulge his taste. He held the office of Secretary to the Royal Society for a
few years, and afterwards visited the Continent. His mind was most acute and inventive; but, though methodical on the
whole, he was at no pains to unfold his original conceptions. He died at an early age in 1731.
DISSERTATION FIFTH.
715
after the retreat of Newton, could safely enter
the lists with the Bernoullis. His most original
work, the Methodus Incrementorum, published in
1715, unfolded the elements of the increase and
decrease of a variable quantity or function. It
was a fine extension of the Differential or Flux¬
ionary Calculus, and constituted a new and im¬
portant branch of the Higher Analysis, which
has since received an appropriate algorithm, and
acquired the appellation of Finite Differences.
The Method of Increments was applied to the
summation of series, and a variety of difficult
problems, of which it afforded easy and rapid so¬
lutions. It furnished the first investigation of the
motions of a vibrating cord, showing that the
harmonic curve is a Trochoid or Prolate Cycloid.
Among other improvements, it contained the cele¬
brated theorem for the expansion of a magni¬
tude, arising from the combination of its succes¬
sive orders of differentials, which has deserved¬
ly retained the name of its ingenious author.
This elegant formula is of extensive use in al¬
most every analytical inquiry, and even performs
the inverse process of Fluxions, by exhibiting in
many cases at once the resulting fluent or integral.
But the notation employed was imperfect, con¬
sisting merely of accents instead of points; and
the Tract, like other works of Taylor, affected
a degree of brevity which borders on obscuri¬
ty. It was therefore elucidated by Nicole, an
eminent French mathematician, in a series of
able dissertations, between the years 1717 and
1727. The Taylorian Theorem itself has been
successively modified, transformed, and extend¬
ed by Maclaurin, Lagrange, and Laplace, whose
names are attached to their several formulae.
The Italian mathematicians contributed ma¬
terially to the progress of the Higher Calculus.
The Integration of a class of Differential Equa¬
tions was proposed by Count Riccati, and solved
in different ways by himself and the sons and
nephews of the first Bernoullis. Manfredi1 in
1707 gave a skilful solution of differential equa¬
tions of the first degree; and in 1722, Vincent,
the son of James Riccati, pursued likewise the
same road. A curious kind of problems was
started by Fagnano,2 another Italian Count, to
determine those Elliptical or Hyperbolic Arcs,
which have their difference expressed by an
algebraical quantity. This led Euler, in 1756,
to invent a very comprehensive method of deter¬
mining particular integrals, that Lagrange im¬
proved in 1766 and 1769, and which he himself
again simplified in 1778. Our ingenious coun¬
tryman Landen has chanced to fall into a simi¬
lar train, having in 1775 converted the formula
for the rectification of the Hyperbola into an¬
other which includes two arcs of an Ellipse, to¬
gether with an algebraical quantity. The rec¬
tification of the Ellipse has been since improved
by Legendre and Ivory.
To obtain the differential of any integral ex¬
pression, is always practicable; the great diffi¬
culty consists in reversing the problem, and find¬
ing the integral which corresponds to a given
differential equation. Such equation must be
rendered complete before the integration is ef¬
fected. It was hence a question of much im¬
portance, to save unavailing efforts, by deter¬
mining the conditions necessarily required for
integration. Euler, as usual, was the first to
discover the rule in 1736; but, only three years
afterwards, it was without any communication
produced by Fontaine and Clairaut. At a later
period, Euler extended the conditions of integra-
bility to the higher orders of Differential Equa¬
tions, which Condorcet demonstrated with equal
simplicity and elegance.
The Modern Analysis thus constantly advan¬
cing, received a capital extension about the middle
of the last century, by what is termed the Cal¬
culus of Partial Differences, which applies with
singular felicity to the solution of the most ardu¬
ous and recondite physical problems. It would
be difficult to communicate any distinct concep¬
tion of this subtle doctrine to the uninitiated,
but the object proposed may be stated generally
as, the method of finding the function of several
1 Born at Bologna in 1674—appointed professor of Mathematics there in 1698, and astronomer to the Institute of Bo¬
logna in 1711. He died in 1739, having produced several excellent works, in which his taste, learning, and science ap¬
pear conspicuous.
2 Born about 1690 at Senegaglia in the Homan State, where he died in 1760. His mathematical researches were pub¬
lished in two volumes quarto, at Pesaro, in 1750. He devoted much attention to the remarkable properties of the curves
called Lemniscata.
716
PRELIMINARY DISSERTATIONS.
variable quantities, from the relation merely of
the Differential Co-efficients contained in their
Complete Differential. The first specimen of
this sort of Integration was given by Euler in
1734; hut D’Alembert expanded the process in
his Discourse on the General Cause of Winds,
which appeared in 1749. It was likewise em¬
ployed by both these illustrious mathematicians
in the rigorous solution of the problem of the
vibrating musical string, the position of any
point in the harmonic curve depending evidently
on the interval of time, as well as on the relation
between the absciss and ordinate. But Euler
left nothing unfinished. In 1762 he resumed the
subject of Partial Differences, and gave a com¬
plete explication of its principles, embodying the
mode of calculation by an appropriate Algo¬
rithm, in a memoir of the Petersburg Acts, en¬
titled, Investigatio functionum ex data differentia-
lium conditione. But still further progress was
made by him in the third volume of his immor¬
tal work on the Differential and Integral Cal¬
culus, which came out in 1770. Euler, having
then advanced to differential equations of the
second order, digested the whole doctrine of
Partial Differences into a clear and systematic
form. Yet several important additions and im¬
provements have been since contributed to this
intricate subject by Lagrange and Laplace, by
Nieuport and Trembley.
The last great accession to the Higher Analy¬
sis, and somewhat resembling the method of
Partial Differences, is the Calculus of Vaviations.
Of this fine theory, the first trace was shown by
the rapid genius of Leibnitz, in his mode of dif¬
ferentiating a curve whose equation itself is sup¬
posed to undergo the minutest alteration. The
controversies of the Bernoullis concerning Isope¬
rimeters and Lines of the Swiftest Descent, aug¬
mented greatly the various resources of that kind
of Analysis. But Euler, combining their dis¬
coveries, produced a new and direct mode of find¬
ing such Maxima and Minima, and compressed
the solutions into a systematic form, in a distinct
treatise published at Lausanne in 1744. This
elaborate performance led the way for the simp¬
ler and most elegant and comprehensive doctrine
created by the early genius of Lagrange, and
invested by him with a commodious notation;
Euler, who was far superior to any feeling oi
jealousy, readily embraced this improvement,
and bestowed on it the denomination of the Cal¬
culus of Variations, of which he explained the
principles and application, after the most com¬
plete manner, in a tract appended to the third
volume of his great work. The distinction be¬
tween Differentials and Variations is rather
subtle, yet may be easily conceived by consid¬
ering the nature of the Parabola. When an
ordinate shifts into a proximate position, both
it and the corresponding absciss acquire Differ¬
entials ; but if the Parameter suffer the minut¬
est alteration, the whole trace of the curve will
vary, and the infinitesimal mutation which the
ordinate thence undergoes is termed its Varia¬
tion. The algorithm adopted to denote Varia¬
tions consists of the Greek letters instead of the
Roman or Italic, which have been appropriated
to the ordinary Differentials. The modes of In¬
tegration used in both forms are fortunately
convertible.
The Integration of Differential Equations has
at length, perhaps, nearly attained that degree
of perfection of which it is susceptible. A
multitude of expedients are devised for effecting
the process in particular cases, hut no general
and direct method has been yet found. To inte¬
grate a differential equation of the first order
composed of two variable quantities, is the pro¬
blem originally known by the title of the Inverse
Method of Tangents, and is commonly solved by
the separation of the indeterminate members,
which brings it to a question of Quadratures.
Some equations consist of parts which, though
not separately integrable, will yet admit ot inte¬
gration when combined. Others are integrated
by the inverse method of factors; but the pro¬
cess by successive approximations may be re¬
garded as in most cases the preferable mode.
The skill of the analyst is chiefly displayed in
the evolution of series the most converging.
Of the Theory of the Infinitesimal Calculus,
various modifications have been offered during
the course of the eighteenth century, which
help to elucidate the subject by their contrast,
and may be regarded as fine speculations, though
they should lead to no material improvements in
the practice. The notion of flowing quantities,
DISSERTATION FIFTH.
*7 1 ’T
/ u
first proposed by Newton, and from which he
framed the terms Fluxions and Fluents, appears,
on the whole, very clear and satisfactory; nor
should the metaphysical objection of introducing
ideas of motion into Geometry have much weight.
Maclaurin was induced, however, by such cavil¬
ling, to devote half a volume to an able but
superfluous discussion of this question. As a re¬
finement on the ancient process of Exhaustions,
the noted method of Prime and Ultimate Ratios,
or of the Relations of Vanishing or Evanescent
Quantities, which Newton preferred in the Prin-
cipici) deserves the highest praise for accuracy of
conception. It has been justly commended by
D’Alembert, who expounded it copiously, and
adopted it as the basis of the Higher Calculus.
The same doctrine was likewise elucidated by
our acute countryman Robins,1 who did not
scruple to seize the occasion of making a coarse
attack on the great Euler. Landen,2 one of
those men so frequent in England whose talents
surmount their narrow education, produced, in
1758, a new form of the Fluxionary Calculus,
under the title of Residual Analysis, which,
though framed with little elegance, may be
deemed, on the whole, an improvement on the
method of ultimate ratios.3 To confer more
consequence on his innovation, he contrived
likewise a set of symbols, and applied his algo¬
rithm to the solution of different problems. But
it never obtained any currency, and soon fell
into oblivion.
The method of Analytical or Derivative Func¬
tions, which has since acquired such celebrity,
was darkly anticipated by Dr Waring, one of
the profoundest but most obscure of algebraical
writers. This elegant theory was concisely
sketched by Lagrange in 1772, and enlarged
thirty years afterwards into a distinct work ; the
same subject having been Heated very fully and
somewhat differently by Arbogast in 1800. It
is grounded chiefly on the inversion of Taylor’s
theorem, the co-efficients of the several terms of
a Derived or Expanded Function involving the
successive orders of its Differentials. But La¬
grange deduces the formula from considerations
purely analytical, and endeavours thence to erect
a science on strict logical principles, entirely
disengaged from ideas of Infinitesimals or of
Vanishing Ratios. It may however be doubt¬
ed whether, with all his ingenuity, he has at¬
tained that object, or gained, indeed, any real
advantage. A mathematician so deeply imbued
as that sublime genius with the spirit of calcu¬
lation, would almost spontaneously regard a pro¬
cess of analysis in the same light as a train of
legitimate reasoning. However satisfactory may
seem the origin of Derivative Functions, if we
examine it closely, we shall probably find the
demonstration to rest merely on the strength of
analogy, which surely is not the most conclusive
sort of argument. But though the method of
Derivations should not possess that logical supe¬
riority over the Fluxionary or Differential Calcu-
1 Benjamin Itobins, born of Quaker parents at Bath in 1707- He discovered early and powerful talents, which he im¬
proved with intense ardour, and soon emancipated himself from the trammels of his cold and narrow sect. Mathematics were
his favourite study, but he enriched his mind by a course of extensive reading and the pursuit of general information. He
became a successful teacher of those sciences in London, and turned his attention to their practical application. Having
cultivated also the art of writing, he distinguished himself by several controversial pieces m science, and even assisted by
his pen the opposition to Walpole’s administration. He was now so well known as a clever writer as to be employed in
correcting Walter’s account of Anson’s Voyage round the World; but finding the performance very poor, he re-composed
the whole. The appearance of this celebrated work in 1748 secured the patronage of the Admiral, and he was appointed
Engineer General to the East India Company. He sailed from England at Christmas 1749, and on his arrival in India
began immediately the fortifications at Madras ; but he fell a sacrifice to that baneful climate on the 29th July 1751. His
various mathematical works are stamped with originality of conception, and composed in a clear, neat, and forcible style.
- John Landen, born at Peakirk in Northamptonshire in January 1719. Bred up to business, he showed an early talent
for Mathematics, which he strenuously cultivated at his leisure hours. In 1762 he was appointed agent to Earl P'itz-
william, an employment which he held till within two years of his death. Besides his separate publications, he communi¬
cated to the Royal Society, at different times, valuable papers on the most difficult parts of mathematical and physical
science, all of them distinguished by depth, ingenuity, and powerful invention. It is only to be regretted that, perhaps
for want of the collision of society, he indulged a dogmatic and pugnacious temper. He died near his native spot on the
loth of January 1790.
3 An example will show how Landen’s operation might be simplified. Let it be required to find the ratio of the dif-
n * .... A*” — Xt*1
ferential of x to that of xn. Assume v a proximate value or state of the variable x; then by division —— =
-f x" - 2 v .;..x -J v n ~ 11 + v n - the number of terms being n. But it is evident that the closer x comes to v, the nearer
will each of these terms approximate to a”-1. Wherefore, at the coincidence of .r with v, the differential of a21 divided by
the differential of x is x"-1, and consequently^ d xn = x”- 1 d x.
718
PRELIMINARY DISSERTATIONS.
lus which its author fondly supposed, yet is the
invention entitled to the highest praise for its
beautiful perspicuity and its ready and most ex¬
tensive application. We have only to regret
that it has required a new system of characters,
when the ordinary notation has become so fa¬
miliar, and attained so great perfection. Such
mutations, like the diversity of languages, may
be deemed a serious evil, since they divert the
attention to the mere accessaries of learning,
and retard or obstruct the acquisition of real
knowledge.1
SECTION II.
APPLICATE SCIENCE.
1. DYNAMICS.
This most important science may be considered
as grounded on the Composition of Forces. Al¬
though the ancients could not fail to remark
that the effect of two oblique forces is equiva¬
lent to the action of some intermediate force, yet
the principle in its simplest form was first dis¬
tinctly stated, after the revival of letters, by the
famous painter Leonardo da Vinci,2 who being
likewise a skilful mechanic and engineer, was
acquainted at that early period with the right
mode of conducting experimental research. He
showed the action of two perpendicular forces
against a point to be the same as what is de¬
noted by the diagonal of a rectangle, of which
they represent the sides. It would hence be
easy to derive the general proposition of oblique
forces; but this beautiful property was suffered
to remain buried amidst an unpublished chaos
of ingenious hints and multifarious projects.
Near a century more elapsed, till it was re-dis¬
covered in its full extent by Stevinus, a Flemish
engineer, who applied it successfully to the ex¬
plication of the common mechanical powers.
About the same time, Galileo, exploring the ac¬
celeration of falling bodies, employed the prin¬
ciple of the composition of forces in determining
the paths described by Projectiles. Another cen¬
tury nearly passed away before Huygens enrich-
1 As an introduction to this studv, the essay of Itobins on Prime and Ultimate Ratio may be read with profit. A very clear
exposition of the principles will be found in the Principiorum Calculi Differentialis et Integralis Expositio Elementaria, a thin
quarto published by L’Huillier of Geneva, at Tubingen, in 1795- But the most complete and perspicuous treatise of
the Higher Analysis unquestionably is Euler’s great work, comprised in seven volumes quarto, printed at different
times between the years 1748 and 1797, and consisting of the Introductio ad Analyses Injinitorum in two volumes, one
volume of the Calculus Dfferentialis^ three volumes of the Calculus Intcgralis, to which have been added two posthu¬
mous volumes. The treatise composed in Italian in two small quarto volumes, by the late Professor Paoli, though
entitled only Elements of Algebra, is of a more comprehensive import, and remarkably clear and elegant.. Ihe German
language has very full and able articles on every part of the Higher Calculus, in Kliigel s Mathematical Dictionary.
The large French work of Lacroix is valuable for its contents, but deficient in clearness and elegance. His Abridge¬
ment seems verv obscure and unsatisfactory. The neatest and most concise treatise on the .Higher Calculus in the
French language is that of Bossut, in two octavo volumes. In English, the Treatise of Fluxions by Simpson may still
be studied with profit. Of Maclaurin’s large work, the first volume contains an excellent account of the ancient method of
Exhaustions, and the second volume is valuable for its physical disquisitions. Our later publications on Fluxions are nu¬
merous, but have not acquired such a character as might entitle them to any particular notice.
2 So called from the name of the place where he was born near Florence in 1452, being.the natural son of a notary.
Bred in an age and country so transcendant in art, he soon distinguished himself by originality of conception, harmony of
design, and elegance of execution. But having likewise ardently cultivated the Mechanical Sciences, he was appointed
director of an Academy of Architecture and Engineering by the Duke of Milan, in which capacity.he constructed the
canal of Mortesana, to supply that city with water. But the political convulsions of that period drove him back to Florence,
where he resumed his former profession. Near the close of his days he accepted from Francis I. an invitation to. France,
where he languished a few months, and expired in the arms of that monarch in 1520. Plis numerous sketches of projects and
machines, with his observations (written backwards), after having been carried to Paris, are now deposited in the Ambrosi¬
an Library at Milan, or among the collections at Florence. A digested abstract of these would form a curious monu¬
ment
DISSERTATION FIFTH.
719
ed Dynamics with his elegant theorems of the
measure of Centrifugal Force in the case of cir¬
cular revolutions. But Newton had already,
and without receiving any communication, ex¬
tended Centrifugal Forces to curve lines in
general, and had thence deduced the elliptical
orbits of the planets. The Dutch philosopher
gave a further expansion to Dynamics, by his
beautiful theory of the oscillation of pendulums.
John Bernoulli1 2 simplified the science of Equi¬
librium or Statics, by proposing the principle of
Virtual Velocities, which Varignon adapted to
the several mechanical powers. This consists
in the fundamental property, that any system at
rest being supposed to suffer a minute derange¬
ment, if the velocity of each body, estimated
in the same direction, be multiplied into its
mass, all those collected products will extinguish
each other. Virtual velocities might be there¬
fore viewed as an extension of the principle of
the lever.
But the same inventive mathematician after¬
wards produced another radical property, which
he styled the Conservation of Living Forces, and
which had been suggested by the ingenious hy¬
pothesis employed by Huygens for discerning
the centre of oscillation. The phrase expressed
that permanence, through all the gradual changes
of any system of connected bodies, in the ag¬
gregate of the products of their masses into the
squares of their velocities. This important prin¬
ciple abridges the solution of various dynamical
problems, and was embraced by Daniel Ber¬
noulli, the son of its propounder, as the basis of
his able and complete theory of Hydrodynamics,
published in 1738.*
Herman,3 a disciple and countryman of the
Bernoullis, and imbued with the taste of the
Leibnitzian school, published, in 1716, under
the title of Phoronomia, the first regular treatise
on Dynamics, drawn up in the analytical or
algebraical form. It was clear and compact, but
incomplete, and not distinguished by much novel¬
ty of conception.
The task of composing a work on Dynamics,
full and original in every part, devolved on
Euler, who exerted all the resources of his pe¬
netrating genius, aided by intense and indefati¬
gable application. This capital performance
came out in 1736, in two quarto volumes, en¬
titled Mechanics, or the Science of Motion, and
exhibited the completest and most elaborate
body of analytical investigation that had been
yet produced.
James,4 the elder Bernoulli, in his mode of
treating the problem of the Centre of Oscilla-
1 John Bernoulli was born at Bale on the 7th of August 1667, being consequently above twelve years younger than his
brother James. He possessed equal genius, but had a keener and more pertinacious temper. Designed by his father to
be bred a merchant, inclination led him to the culture of letters, which, from the example and instructions of his brother,
he afterwards exchanged for the pursuit of mathematics. The force of his inventive faculty he soon displayed in the reso¬
lution of those arduous questions which then agitated the scientific world. The spirit of chivalry had about this period passed
over to the learned, and the practice of sending mutual challenges incited application and fomented the talent of discovery.
Along with Huygens and Leibnitz, he was the first in solving "the problem proposed by his brother, to determine the na¬
ture of the Catenarian Curve, or the flexure formed by an equable chain suspended from both ends. Having completed
the usual course of education, and turned his thoughts in 1693 to the medical profession, he took a degree in j)hysic. He
now travelled into France, and spent some time at the country-seat of the Marquis de I’Hopital, whom he taught the New
Calculus. Proceeding next to Holland, he was appointed in 1695 Professor of Medicine and Mathematics (for these
sciences were strangely conjoined) in the University of Groningen. The fame he there acquired by his lectures and
writings appears to have awakened the jealousy or bigotry of the Calvinistic clergy, who brought a serious charge against
him, for impugning the doctrine of the resurrection in a Thesis maintained by one of his scholars, and composed or corrected bv
himself, which represented the body as in a state of continual mutation, not only the liquid, but even the solid parts being
successively absorbed and renewed, and no particle of the composition remaining after a very short term of years. The
coolness of the magistrates, however, effectually silenced the ignorant clamour of the Synod, and Bernoulli was pressed to
remain in Holland, with flattering offers of promotion. But Bernoulli preferred his native city, whither he was sponta¬
neously invited to succeed his brother. In this honourable station he spent the rest of a long life in extending, by the ac¬
tivity of his genius, every branch of Mathematical and Physical Science. He corresponded with all the foreign societies,
and the numerous prizes he bore away proved a source of income. His treatise on seamanship came out in 1714, and his
dissertation on the elliptical figure of the planets appeared in 1730. But his various philosophical papers were carefully
collected into four quarto volumes, and published in 1742 at Geneva and Lausanne. He died full of years and of glory on
the 1st of January 1748.
2 These two properties—Virtual Velocities and Conservation of Living Forces—are easily and directly proved from the
elementary principle of the composition of forces. See Elements of Natural Philosophy, p. 134, 135.
3 Born at Bale in 1678. Having been six years Professor of Mathematics at Padua, he accepted an invitation in 1724
to Petersburg; but not long afterwards returning home, he became Professor of Morals and Public Law in his native
city, where he died in 1733.
4 James Bernoulli, the first of a most illustrious race of mathematicians, was born on the 27th December 1654, at Bale,
and educated in the seminary of that frontier city. His father wished him to follow the profession of divinity, but the im-
720
PRELIMINARY DISSERTATIONS.
tion, struck out a more direct and ingenious
procedure, ky which the forces exerted aie re¬
solved into separate portions, and an equality
obtained between their accelerating and retard¬
ing influence. This fine conception, alter the
lapse of forty years, appears to have prompted
D’Alembert1 to the discovery of the simple and
general principle on which he framed his Trea¬
tise of Dynamics in 1743. In every system of
bodies acting mutually, their several movements
at any instant of time may be decomposed into
two portions, one which is retained in the next
instant, and the other spent; and since an equi¬
librium must obtain among the lost motions, an
expression is hence derived for the motions that
are preserved. The most intricate questions in
Dynamics were thus reduced to mere statical
problems, and solved constantly in the same easy
and uniform way. Maclaurin’s method of ex¬
pounding forces by co-ordinates facilitated still
further the application of this principle, which
D’Alembert in 1744 and 1752 extended like¬
wise to Hydrodynamics, comprehending both
the motion and the resistance of fluids.
The slightest incident has often led to the
most interesting discoveries. Few would sup¬
pose that the spinning of a common top in¬
volves the most diflicult conditions in Dyna¬
mics, and serves to explain all the intricacies
of the planetary vertiginous motions. Segner,
a celebrated professor of mathematics at Got¬
tingen, and afterwards at Halle, and a man of
original and independent mind, published, in
1755, a short dissertation, with the modest title
of Specimen Theorice Turbinum, wherein he show¬
ed that every body having a determinate figure,
which after combined impulsions is abandoned
in free space, will, besides its progressive mo¬
tion, perform simultaneously, and without the
smallest interference, a constant and uniform re¬
volution about each of three principal axes mu¬
tually perpendicular, and passing through the
centre of gravity. These axes of rotation possess
some beautiful but abstruse properties, which the
pulse of native genius burst through constraint, and hurried him into the ardent pursuit of geometry and astronomy, which
he cultivated in private. Alluding to this circumstance, he chose for his device Phaethon driving the chariot of the Sun,
with the motto, “ Invito patre sidera verso." He began his travels for information in 1676, visited Geneva, traversed
France, and eagerly sought the society of men of learning and science. In 1680 he descended to the Netherlands and Hol¬
land, passed over to F.ngland, and frequented the philosophical meetings in London. .After his return home m 1632, he
gave a course of mechanical lectures, in which he exhibited the new discoveries. Being appointed Professor of Mathe¬
matics in 1687, the fame of his vast attainments drew crowds of strangers to the academy. His genius was a torch of illu¬
mination, and the most elegant simplicity distinguished all his profound inventions. In conjunction with his younger bro¬
ther, he not onlv found out the secret of the Differential Calculus, on which Leibnitz had given a very short and obscure
essay in the Leipsic Acts, but unfolded the principles with such superior talent and address, that the German philosopher
had the generosity to regard him as entitled to share in the honour of the great discovery. He pursued the Aew Calculus
with extreme ardour, and applied it most happily to a variety of arduous investigations: He greatly improved the Method
of Series, extended the Theory of Curve Lines, approximated to the rectification of the Parabola, and discovered man%
beautiful properties of cycloids, epicycloids, and spirals. With the logarithmic spiral, which he discovered to renovate
itself by evolution, his fancy was so much struck, that, in imitation of Archimedes, but in allusion to the sublime prospect
of resurrection, when he should “ shuffle off this mortal coil,” and rise like Phoenix from her ashes, he directed with a fine
enthusiasm this curve to be inscribed on his tomb, with the Ovidian line, “ Eadem mutata resurgo. . ,
But such nrightv strides required proportional exertion of intellect, and this intense and unremitting applrcatron under¬
mined the constitution of Bernoulli, and carried him to a premature grave. He sunk under a, slow fever on the 16th Au¬
gust 1705. He had nearly finished his great work on the doctrine of series, and the calculation of annuitres and chances,
entitled De Conjectewdi, which was published in 1713. His other miscellaneous productions wrere not collected till
1744, when thev came out in two quarto volumes at Geneva.
1 Born at Paris 16th November 1717, the fruit of an illicit amour with a lady of high rank, who exposed her infant; but
the father, listening to the calls of nature, settled a competent annuity. Pie was educated by the Jansenists in the Col¬
lege de Quatre Nations, where he gave early tokens of capacity and genius. After finishing the usual course, he letuined
to the family of his nurse, with whom he lived forty years in great simplicity, cherishing his independence, and devoting
himself wholly to mathematical pursuits and the cultivation of general literature. Such was the progress he made, that he
was admitted, at the age of 24, a member of the Academy of Sciences, and two years afterwards he produced his 1 realise
on Dynamics. The germs of the Calculus of Partial Differences appeared in his Dissertation on Winds, which obtained
the prize from the Academy of Berlin in 1746. His new dynamical principle he applied to the investigation of the Earth s
vertiginous motion in 1746, and to the theory of the resistance of fluids in 1752. About this time he engaged with Diderot
in the compilation of the Encyclopedie, wrote the famous introductory discourse, and furnished several capital articles, espe¬
cially in mathematical science. But he now sought to distinguish himself likewise in philosophy and literature, and pub¬
lished a variety of tracts, which gave occasion to controversy and violent opposition. But this hostility carried his reputa
tion to a higher pitch. He corresponded with the great Frederick of Prussia, but refused the flattering offers of that Mo¬
narch and of the Empress Catharine of Russia. The literary honours he enjoyed at home were more agreeable to bis
taste. Having become secretary to both Academies, he was esteemed the head of the philosophical body at Paris. His
works are numerous in various departments. He was a close, accurate, and original thinker ; and his style partakes of the
tame qualities, neat, hard, and precise. He died on the 29th October 1783.
DISSERTATION FIFTH.
721
great Euler investigated with that profound talent
and luminous method which distinguish all his
productions. The curious discovery of Segner
drew likewise the attention of D’Alembert and
Lagrange, and deserves to he regarded as one
of the most important additions ever made to the
science of Dynamics. It has contributed signal¬
ly to the advancement of physical astronomy,
and thrown a clear light on the theory of the
nutation of the earth’s axis, and of the precession
of the equinoxes.
Dynamics might seem to have nearly reached
its perfection, when Lagrange in 1788, by com¬
bining the principle of D’Alembert with that of
virtual velocities, converted the whole into an
absolute analytical science. His procedure was
to refer the efforts of every particle of a moving
system to three mutual perpendiculars, and
thence derive three several differential equations,
which being integrated, would give the final
solution of the problem. But to discover a ge¬
neral form of integration is the great difficulty
which still remains. All attempts to remove
this obstacle have hitherto failed, and we are
reluctantly obliged to remain satisfied with mere¬
ly partial and approximative methods. It must
be confessed that the suhtilties of the Higher Ana¬
lysis have been often displayed with very little
effect, and that the most celebrated mathemati¬
cians, in resolving some arduous questions, es¬
pecially those involving physical considerations,
have still not advanced beyond the vague and
imperfect results which sagacity had with very
slender aid already attained. Analysts affect too
much the air of generalizing, and deceive them¬
selves with expectations which are never destined
to be realized. It is thus that Nature appears
to set limits to the soaring of human genius.
Statics and Dynamics, though really ground¬
ed on observation, depend on principles so
simple, and apparently so congruous to reason,
that they are often derived from mere abstract
considerations, or the consonance of geometrical
analogies. But the constituent properties of
bodies lie beyond the reach of anticipation, and
can be explored only by experiment. Every
body may be divided into parts, and each of
these parts again subdivided; nor has any limit
been yet found to this repeated process of de¬
composition. Each separate portion likewise re¬
tains all the properties of the mass from which
it was detached. Hence the corpuscular ele¬
ments, or the materials that form bodies, have
precisely the same character as the compounds
themselves. But though imagination represents
an interminable series of subdivisions, such can¬
not be the actual constitution of nature, which
is always defined by number and measure. We
may therefore infer the existence of certain ulti¬
mate portions or atoms, endued with the very
fewest qualities, but which by their various com¬
binations constitute the particles of matter, or
form the corpuscular composition of bodies.
Every body whatever can have its dimensions
contracted or dilated by the application of force;
and the extent of this effect is limited only by
our circumscribed power. The atoms must
hence be held together by some mutual appe¬
tite, whose intensity varies with the interme¬
diate distance. This tendency is evidently re¬
pulsive within a certain interval, and attractive
beyond it. But the essence of matter consists
in impenetrability, and therefore the repulsive
force must increase from approximation above
any finite measure. The inherent power, thus
variously changing at near intervals, will merge
at remote distances into the great law of attrac¬
tion.
Such is a brief outline of the reasoning by
which the ingenious Boscovich 1 in 1759 sup¬
ported his beautiful Theory of the Constitution
of the Universe. It was partly suggested per¬
haps by the modification first proposed by Clai-
raut on the Newtonian System, which assumed
1 Roger Joseph Boscovich, born in the small republic of Ragusa on the 11th of May 1711; received his elementary
instruction under the Jesuits, who noticed the promising talents of the youth, and sent him to complete his education in
them collego at Rome. He soon attained great eminence in erudition and science ; and became Professor of Mathematics
and Astronomy successively at Rome, Pavia, and Milan. In 1753 he performed the mensuration of a degree in the Papal
Mates, and during the intervals of that laborious occupation he composed in three octavo volumes a treatise of ele¬
mentary mathematics, remarkable for its simplicity and elegance. He was afterwards employed in several public negotia¬
tions, and the claims of his native state brought him to London, where he spent some time, mingling in the societies of the
D1SS. V. Av
PRELIMINARY DISSERTATIONS.
722
the attractive power to be composed of a small
portion of the inverse cube of the distance, joined
to the ordinary term of the inverse square. But
the idea of the Ragusan Philosopher was far
more general, exhibiting this power as what
algebraists call a function of the distance. He
rendered the conception still cleaiei by means
of a primordial curve stretching to indefinite
distance, of which the ordinates on either side
of the axis indicate the corresponding attractive
or repulsive force. The extended horizontal
branch includes the solar attraction, the alter¬
nate convolutions of the curve mark the proxi¬
mate changes of cohesion, and the final descend¬
ing branch, by its continual approach to a per¬
pendicular, intimates the insuperable repulsion
which prevents the collapse of matter. The in¬
termediate alternations of the curve are un¬
known ; hut as in their progress they cross the
extended absciss from above or below, they
mark the limits of instability or stability. In
this way the different constitution of solid, li¬
quid, or gaseous substances may he represented.
The atoms being likewise variously grouped,
must by their blended action produce that im¬
mense diversity of effects which animate the
spectacle of the external world.
It is to he regretted that Boscovich obscured
his fine theory by an infusion of scholastic me¬
taphysics : He maintained that those atoms or
physical points had no magnitude, or differed
from mathematical points only in being endued
with primary force. But this difficulty, which
proceeds rather from our modes of conception
than from the actual state of things, might he
obviated, by supposing the atoms to have real
dimensions, though far smaller than any assigned
measure. The primordial curve can likewise he
presumed to advance, not by insensible grada¬
tions, hut by a succession of most minute steps.
This slight modification would accord with the
tendency of atoms to collect into certain regular
groups, a property which seems deducible from
the principles of crystallography and the theory
of definite proportions. We thus catch a glimpse
of the recondite composition of corpuscular ele¬
ments.
The Boscovichian Theory reduces the inves¬
tigation of the properties of bodies to the utmost
simplicity, and may be regarded as a very happy
extension of the great law of attraction. Why
it has not been received with more favour, espe¬
cially on the Continent, might provoke some
surprise. Being probably considered as too
speculative, it has never been studied with the
attention it deserved. Purged of its antiquated
metaphysics and crude chemical notions, it would
form the best introduction to general physical
science.
A portion of that beautiful theory, however, is
now, ina modified shape, very commonly received,
especially by the continental philosophers, who
view the constituent molecules as held together by
their mutual attraction opposed to the repulsive
energy among the attached particles of heat. It
is a supposition which readily explains the ge¬
neral properties of bodies, and serves to elucidate
their structure and internal operations.
The Boscovichian System assumed the gene¬
ral principle, that every substance whatever is
capable of contraction and dilatation. But this
was not admitted at the time in its full extent,
the noted experiment of the Florentine Acade¬
micians seeming to have established the abso¬
lute incompressibility of water. The conclusion
however was too hastily drawn; for though the
liquid included within a hollow sphere of gold
resisted the blows of a hammer, and burst the
shell, yet the celerity with which it spirted
through the crevice, only displayed the elastic
force resulting, as Bellegradi rightly observed,
from an expansive effort to recover its previous
condition. But the actual condensation of water
and other liquids under pressure was first shown
learned, and composed his Poem on Eclipses, which exhibits a neat view of the Newtonian Philosophy. ence e
with an embassy to Vienna, where he observed the transit of Venus in 1769. On the suppression of the Jesui s y op
Ganganelli in 1772, he was invited to France, and appointed Director of Optics. But the Parisian philosop ers eric
his school of theology, and undervalued his scientific talents; and after a residence of ten years, he returned m isgus
Italy, and printed in 1784 his Opuscula in five quarto volumes at Bassano. Chagrin and vexation in the dec ine o i
preyed on his sensitive mind; and he sunk by degrees into a deep melancholy, which ended in utter and hopeless insam y.
But from this deplorable state he was relieved by death on the 13th of February 1787. Boscovich possessed a tine geome¬
trical taste, joined to considerable powers of invention in a variety of subjects.
DISSERTATION FIFTH.
723
experimentally in 1762 by our ingenious coun¬
tryman Mr Canton,1 who measured the effect by
means of a sort of large open thermometer, con¬
taining the fluid in a very capacious glass ball,
which terminated in a long capillary tube. Pro¬
fessor Zimmerman of Brunswick in 1779 carried
this condensation much farther, having introdu¬
ced water into the cavity of a brass cannon, and
compressed it by a force exceeding the weight
of 300 atmospheres. Still the popular and ele¬
mentary treatises, neglecting such decisive facts,
continued to repeat with complacency the para¬
doxical assertion, that water retains the same
volume under every degree of compression. Nor
was the public recalled from its careless ac¬
quiescence, till the mention of some experiments
of enormous compression performed at great
depths in the Atlantic Ocean. But the cele¬
brated Oerstedt of Copenhagen has lately made
an elegant improvement of Canton’s method, by
which the condensing power exerted on water
by a progressive pressure as high as thirty at¬
mospheres, is most easily and accurately measur¬
ed. By a further extension of the apparatus, the
contractility of various solid substances could
likewise be readily ascertained, which might
lead to the detection of facts interesting in the
economy of Nature.
2. HYDROSTATICS AND PNEUMATICS.
The theory of the Pressure and Equilibrium
of Fluids is readily deduced from the principles
of Statics, joined to the consideration of the in¬
ternal mobility of the fluid particles, or their
absolute indifference to maintaining figure. But
the ordinary demonstration seems incomplete,
without taking likewise into view that Compres¬
sibility, which belongs in a more eminent degree
to fluid than even to solid substances. The
particles retreat from the action of pressure, con¬
tracting on all sides, till the repulsion occasion¬
ed by their mutual approach becomes a sufficient
countervailing force, diffusible in every direction.
Hydrostatics is therefore a complete science.
The conditions of equilibrium had been discover¬
ed by Archimedes, but Stevinus traced the effects
of fluid pressure, which Pascal afterwards ex¬
plained.
Hydrostatics, or rather Hydrodynamics, which
treats of the Motion of Fluids, is a subject of far
more difficult investigation. Torricelli gave the
first traces of this theory, which exercised the sa¬
gacity of Newton, and yet required considerable
correction. The fundamental problem is to find
the discharge of water through a small hole in
the bottom of a cylinder filled with the fluid.
This efflux amounts only to about five eighth
parts of the first emission; and to explain the
discrepancy, the immortal author of the Princi-
pia had recourse to the supposition of a cataract,
or funnel-shaped conoid, by which the various
streamlets bend their course towards the orifice.
But the theory was not investigated in a more
rigorous and systematic manner, till half a cen¬
tury afterwards, when Daniel Bernoulli2 pub¬
lished his important treatise of Hydrodynamics.
1 John Canton, one of our most diligent, skilful, and accurate experimental philosophers, was born at Stroud in Glou¬
cestershire in 1718- His father, a broad-cloth weaver, bred him to the same trade; but the youth, incited by the lessons
of an elementary teacher, had from his earliest years imbibed a taste for mathematical studies, and continued to devote
every leisure moment to those fascinating pursuits. The ingenuity he showed in constructing sun-dials drew the notice of
his more intelligent neighbours, who kindly fostered his efforts, and lent him instructive books. Nothing has contributed
more in England, not only to spread general information, but to awaken latent genius, than the circulation of popular com-
pendiums and dictionaries of science. With these aids the ardent application of Canton made such rapid and striking pro¬
gress, that his patrons counselled him to quit the loom and repair to the metropolis, the great mart of talent. In 1738 he
was admitted assistant in a mathematical school in Spital Square, and afterwards became partner and successor in the con¬
cern, which he conducted during the rest of his life. Without aspiring to the higher walks of science, he was active in the
search of knowledge. He devised new experiments, and carefully repeated those in vogue; thus extending our acquaint¬
ance with Electricity, Magnetism, and some parts of Physical Chemistry. But his career was short, for he died of a dropsy
in 1772.
2 Daniel, son of John Bernoulli, born at Groningen 9th February 1700, conjoined the hereditary talent with a mild
and balanced disposition. He was only five years old when his father returned to Bale, where he prosecuted his educa¬
tion, and enjoyed the peculiar advantages of paternal aid, and the inciting emulation of his brother Nicholas. Being des¬
tined for the profession of physic, he sought to improve his medical attainments by resorting to the schools of Italy. There
he published in 1724 his Exercitationes Mathematicce, and already acquired such reputation that he was pressed to become
director of an academy projected at Genoa. This offer, however, he declined, but soon afterwards accepted, along with his
724
PRELIMINARY DISSERTATIONS.
The subject was next discussed in 1744 by
D’Alembert, and with the depth and origina¬
lity which distinguish all his productions. This
celebrated philosopher, eight years thereafter,
advanced to the arduous investigation of the Re¬
sistance of Fluids, and displayed the resources of
his invention, in evolving a variety of ingenious
formulee. Euler likewise, by a series of repeat¬
ed progressive essays between the years 1755
and 1772, successively simplified the theory of
Hydrodynamics, and reduced the doctrine into
a strict analytical form, the vvhole comprised in
two differential equations of the second order.
Lagrange followed next, and discussed in 1781
the chief difficulties which encumbered the
theory; and five years thereafter, he simplified
still further the mode of investigation in his
Mkcanique Analytique.
But it is rather mortifying to confess, that
these refined speculations are of little avail in
the practice of the science. It is indeed impos¬
sible, by any effort of analysis, to embrace all
the physical conditions concerned in such an in¬
tricate system of internal corpuscular motions.
Assumptions become necessary for the sake of
abbreviation, and the process of integration it¬
self is seldom if ever complete. The results drawn
from such laborious researches are, after all this
parade of rigid accuracy, to be viewed as only
near approximations, which could often be at¬
tained by much easier means. It would there¬
fore be preferable in many cases to study the
physical relations more closely, avoiding the
abuse of abstract calculation, and to rest satis¬
fied with arriving at the conclusions by a sort
of balance of errors. In the sober application
of analysis, Daniel Bernoulli was singularly
happy, guiding his steps always by the light of ex¬
periment and observation. And, since the result
of the most elaborate investigation is very seldom
better than a simple approximation, it seems more
j udicious in such researches to lay the chief stress
on the estimate of physical principles. After
the most strenuous efforts of genius displayed
during the eighteenth century, the theory of the
motions of fluids has really not arrived at more
precise conclusions than those first assigned by
the penetration of Newton. Nay, so far from
reaching any higher degree of perfection, some
of the recondite speculations of Lagrange and
Poisson, those particularly relating to the ex¬
tent and celerity of waves, and the general un-
dulatory commotions in fluids, involve conse¬
quences which are palpably at variance with the
known phaenomena of Nature. In such compli¬
cated investigations, the safest mode of proceed¬
ing is to follow the example of astronomers, who
determine the co-efficients of the several analy¬
tical formulae, by the comparison of observations.
The simplest and most elementary theory is
hence rendered subservient to practical use.
The principles of Hydrostatics constitute the
grounds of Naval Architecture, which embraces
the theory of the Construction and Sailing of
Ships. To this very important branch of sci¬
ence, Euler turned his mighty talents, and pro¬
duced in 1749 a large and elaborate work, con¬
taining a series of ingenious propositions, but
which unfortunately are not the best adapted to
actual practice. About the same time the ce¬
lebrated Bouguer,1 combining geometrical skill
with the stores of experimental knowledge, exa-
brother, a more flattering invitation from Peter the Great of Russia, to hold a prominent station in the Institute then
founded in the new capital. Nicholas soon sunk under the severity of that northern climate, but Daniel remained till
1733, when he was appointed to the professorship of physic at Bale. In quitting Russia, he did not forget to recommend
for successor his countryman Euler, who, though seven years younger, had been associated in some degree as his fellow-
student. Bernoulli during the rest of his life pursued at home his philosophical investigations with unwearied assiduity
and eminent success. He gained or shared most of the prizes given by the different learned bodies over Europe. In
1734 he divided with his father the honour of solving the very difficult problem of the inclination of the orbits of the
planets. But his great rival was Euler, nor did their frequent collision ever cool the warmth of mutual friendship. Ber¬
noulli long enjoyed the high respect due to his talents, his virtues, and many amiable qualities. He died on the 17th
March 1782.
1 Peter Bouguer, born on the 10th of February 1698, at Croisic in Lower Brittany, where his father was royal profes¬
sor of Hydrography, and had shown abilities by publishing an esteemed treatise of Navigation. Under such guidance he
imbibed a very early taste for mathematics, and having distinguished himself at the Jesuits’ college of Vannes, he was, af¬
ter a strict public examination, found qualified to succeed his father when only fifteen years old. Notwithstanding his im¬
mature age, he discharged the duties of his office with dignity and success. But he found leisure also to pursue his pri¬
vate studies, and in 1727 he gained a prize of the Parisian Academy for a paper on the Masting of Ships, and obtained
other prizes in the following years. His Treatise on the Gradation of Light appeared in 1729, and established his high re¬
putation. His celebrity always increasing, he was appointed in 1735 to join the famous scientific expedition sent out to
DISSERTATION FIFTH.
725
mined the subject in its details, and reduced
the theory into a form remarkably simple and
elegant. When a body floats on the surface of
water, it is held in equilibrium by the action of
two equal and opposite perpendicular forces
passing through its centre of gravity, and the
centre of buoyancy or that of the fluid dis¬
placed by immersion. Its weight draws it
downwards, while the buoyant effort presses it
directly upwards in the line of support, the ver¬
tical position of those centres being essential to
the stability of flotation. The centre of buoyancy
does not remain constant, but shifts with the
inclination of the natant body. The sustaining
force may be conceived to act at any point in
its direction, and consequently where the line
of support crosses the axis. On this point of
concourse, Bouguer bestowed the appropriate
name of Metacentre, as the limiting position
which determines the conditions of flotation,
there being stability whenever it stands above
the centre of gravity, but the contrary if it
falls below. This useful theorem he had in¬
vented in 1746; and nine years afterwards was
published his investigation of the several motions
of ships under the impulse of wind. That inquiry
rested too much, however, on the ordinary re¬
sistance of fluids, which needs material correc¬
tions. It is not very difficult to measure the
primary shock of the fluid particles; but, since
they accumulate on the front of the body while it
advances, the most arduous task is to estimate
the force expended, in turning them aside into
the general mass, and restoring the diffuse qui¬
escence. To include such multiplied conditions,
which are still essential towards a correct and
complete solution of the problem, would evi¬
dently transcend the powers of the most com¬
plex analysis. The utmost that can be effected
is only an approximation, which may be easily
obtained by adopting a simplified hypothesis,
and correcting the terms from observation.
The most complete set of experiments on the
resistance of water in narrow canals was made
by Bossut between the years 1766 and 1775,
and forms the groundwork of his valuable theo¬
retical and practical treatise on Hydrodynamics.
It hence appears that water has its celerity re¬
duced to the tenth part, by flowing through a
smooth leaden pipe whose length is four thou¬
sand times its diameter, or that every particle of
the fluid has its motion extinguished and suc¬
cessively renewed ten times during the passage
along the extended cavity, by grazing against sides
and again relapsing into the current. If in this
case, therefore, the whole pressure were distin¬
guished into an hundred equal parts, one of
these alone generates the velocity, the remain¬
ing ninety-nine parts being expended in merely
surmounting the impediments to the flow. A
similar consideration was made the basis of
Practical Hydrodynamics by Dubuat, who in
1786 gave simple and easy formulae, for deter¬
mining the discharge of pipes, canals, and rivers.
Smeaton, our celebrated engineer, performed
a series of experiments by means of small mo¬
dels in 1759, on the action of water and wind
against the floats or sails of mills. The results
obtained on such a narrow scale have, notwith¬
standing their unavoidable imperfection, been
adopted into general practice. Other later ob¬
servations made by Banks have likewise gain¬
ed credit among our artisans. The most skilful
experiments however of that kind were institut¬
ed by Eytelwein of Berlin in 1799. But the
recent observations made at Fahlun in Sweden
are decidedly the completest and most scientific
which have been yet performed.
The usual method of investigating the resist¬
ance of Fluids is to estimate the momentary
shock or impact of their particles against the
anterior surface of the penetrating body. But
a more complete and elegant solution may be
derived, from considering the pressure caused by
measure a degree of the meridian under the equator. He spent ten years on the lofty chain of the Andes, prosecuting
with unabated ardour a variety of new, ingenious, and important researches. On his return to Europe, he poured forth a
flood of most interesting information in most branches of physical science. His last works related to the construction
and sailing of ships. Incessant labour and intense application had worn out his constitution, and he expired on the
15th of August 1758. Few persons have contributed so largely to the promotion of Natural Philosophy as Bouguer,
who united the rare qualities of an able mathematician and a skilful and accurate experimenter. Like studious per¬
sons little conversant with the world, he is alleged, however, to have had the misfortune of a jealous and irritable
temper.
728
PRELIMINARY DISSERTATIONS.
tlie incessant accumulation, and therefoie con¬
densation, of the medium in the track of the
passage through it. There is likewise another
retarding force occasioned by the constant dila¬
tation of the fluid in the rear of the advancing
body. In the case of the gaseous media, this
impediment often rises to a great amount.
When the velocity of penetration, for instance,
through common air exceeds 1350 feet each se¬
cond, a vacuum is formed behind the missile,
which thence suffers a retardation equal to the
weight of a whole atmosphere. This conse¬
quence was first remarked by Robins in the
flight of cannon-balls, and it completely de¬
ranges the parabolic theory. He was mistaken
however in restricting the effect to such extreme¬
ly swift motions; for the same consideration ap¬
plies in every degree of rapidity, the condensa¬
tion and corresponding dilatation of the air close
to the anterior and the posterior surfaces of the
ball being proportional to the square of its cele¬
rity. Hence the measure of retardation is al¬
ways affected by the shape of the rear, as well
as of the front of the projectile.
Robins employed an ingenious method of de¬
termining the impulse of halls, by firing them
against a heavy loaded pendulum, whose de¬
flection correctly indicated the momentum thus
communicated; and by intercepting the flight
at different distances, it was easy to discover the
loss of velocity, and consequently the resistance
opposed by the air. Borda, assuming a much
lower scale of velocities, followed a different
mode in the valuable set of experiments on the re¬
tardation arising from fluids which he performed
between the years 1763 and 1769. He particu¬
larly noticed the influence of the figure of the
hinder part of a moving body in modifying the re¬
sistance of the medium. Hr Hutton adopted the
Ballistic Pendulum of Robins in his most exten¬
sive series of experiments executed with great cir¬
cumspection on Woolwich Common during the
years 1790 and 1791. It comprehends the whole
range of velocities, from 5 feet in a second to
2000. The resistance appeared to increase in a
ratio faster than the square of the velocity, and
therefore Hutton proposed to increase the index
2 by a small variable addition. This modifica¬
tion however is not conformable to the physical
principles. Coulomb has shown, by his very
delicate Balance of Torsion, that, in the case of
extremely slow motions, the resistance of fluids
is proportional to the velocity simply. The
complete expression of resistance therefore in¬
cludes probably, besides the second power, like¬
wise the first and third, of which the co-efficients
are to be found by a scrupulous comparison of
the results. More precise experiments are still
wanted, to improve the science of Gunnery.
The flow of air through a small orifice suffers
nearly the same loss as water, or delivers only
about five eighth parts of the measure indicated
by theory. But, in passing through long trains
of pipes, the several gases appear, from some re¬
cent though very limited experiments of Girard,
to encounter proportionally still greater obstruc¬
tion ; insomuch that a stream of air would re¬
quire a pressure exceeding tenfold its emergent
force, to enable it to work its way through a
pipe whose length is 180 times the diameter.1
It is a question hitherto overlooked, but of real
importance in the economical distribution of pipes
for conveying coal or oil gas.
Water and other liquids, when heated, are
observed to flow more freely from a very narrow
aperture or through a long capillary bore, ow¬
ing evidently to increased fluidity or the greater
internal mobility of their particles. From a
very slender syphon pure water near boiling will
drop six times faster than on the verge of freez¬
ing. But air seems not affected in the same
way: If it be forced by a certain pressure
through a long capillary tube of glass laid hori¬
zontally in a water bath, the current, so far
from accelerating, will become retarded by the
application of heat. This discrepancy is occa¬
sioned by the dilatation of the fluid, which en¬
feebles the rate of discharge.
The progress of chemistry during the eigh¬
teenth century has brought us acquainted with
1 The general complexion of the fact had been accidentally noticed before at Wilkins’ great iron-works m \Y ales, w ere
the nozzel of the bellows of a blast furnace being inserted into the one end of a train of large pipes, the efflux trom t ic
other end scarcely affected the flame of a candle.
DISSERTATION FIFTH.
727
other kinds of air or gases besides the atmos¬
pheric. But their mechanical properties are
not so easily determined. The very inferior
density of hydrogen gas was first discovered in
1766 by Cavendish, who made it ten times lighter
than common air. By some late experimenters
it has been represented as even sixteen times
lighter, when carried to the highest state of pa¬
rity. This conclusion, however, appears %rery
doubtful, since it involves hypothetical consider¬
ations. It is very difficult to detach the latent
moisture and to w~eigh accurately the dried
gases contained in large glass balloons. This
experiment, though quite practicable, remains
still to be performed; and there is reason to sus¬
pect that the alleged lightness of hydrogen gas
has been much exaggerated. But Pneuma¬
tic theory suggests a method of ascertaining
the relative density of any gas, which is at once
most ready, and susceptible of very considerable
accuracy. It is only to observe the time of a given
discharge of the fluids, from a small orifice, and
under the action of a certain pressure; when
the density will, in like circumstances, be in¬
versely as the square of the number of seconds
elapsed.1 But the celerity of the flow may be
discovered indirectly by another mode, which is
practised with the greatest ease and nicety by
any person possessing a fine musical ear. He
needs only to send the gas through a detached
organ pipe, and distinguish the precise note
which it yields, or find another pipe in unison
with it; the inverse subduplicate ratio of these
lengths will express the relative densities of
the fluids. This suggestion deserves to be pur¬
sued.
When air is thrown by pressure through a
small round hole, either into free space or into
a close vessel with a wider exit, it must evident¬
ly spread in diverging streamlets, and suffer a
certain degree of rarefaction. The radiating
discharge of a fluid thus involves a princi¬
ple,2 which explains a number of curious facts.
Water rushing in a foaming current along a
pipe or confined channel, leaves a partial va¬
cuity at the sides, from which a small insert¬
ed syphon would draw a stagnant liquid to
a considerable height. This was particularly
noticed in 1795 by Venturi, who termed the
property Lateral Action. On the same principle
depends the suspension and play of a small ball
above a jet of air from hydraulic bellows or a
condensing engine. Hence likewise an explica¬
tion of a seeming paradox in the action of fluids,
lately considered by the ingenious Hachette.
If a pipe bent directly downwards swell below
into a cone with an horizontal base, encircled by
a narrow rim, and pierced with a central hole, a
strong current of air issuing through that aper¬
ture, but having a circular plate fitting closely
with a weight appended, so far from blowing
away the water, will draw it forcibly and sup¬
port the load. The sheet of air between the
opposite surfaces being kept rarefied by its di¬
verging streamlets, the external atmosphere
presses strongly upwards. The experiment is
reducible to the simplest form; for a common
tobacco-pipe held inverted, will by mere blowing
be made to suspend a card from its bowl. The
safety-valve therefore of a high pressure engine
may not always afford the expected protection;
under peculiar circumstances it will remain
attached at a very small distance, allowing only
a partial escape of steam in very thin diverging
streamlets.
The like effect is produced in the expanding
discharge of water from a narrow circular outlet.
Here the streamlets dividing from the centre,
draw in air and keep it rarefied by their rapid di¬
vergence. The adhesion fails with a rectangular
aperture, the streamlets then proceeding in paral¬
lel lines. On a modification of the same principle
depends an elegant experiment of Ampere. If
water be projected horizontally from the bottom
of a tall vessel through a vertical slit, this able phi¬
losopher observed that the sharp parabolic stream
will at a certain distance form a sort of node, and
sink into a broad arch. The different retardations
of the exterior streamlets appear in this case to
determine the change of appearance.
These methods of experimenting present themselves to a mathematician, but perhaps the first intimation of them was
given in the Experimental Inquiry into the Nature and Propagation of Heat, p. 534. Since a delicate musical ear can
aistinguish even the quarter of a note, the error of observation in the second mode should not exceed the 64th part, which
seems a nearer approximation than is attainable in any other way.
* See the article Meteorology in this Encyclopaedia.
728
PRELIMINARY DISSERTATIONS.
Brook Taylor had shown that a musical chord
during its vibrations has the swelling outline of
a trochoid. But Euler and D’Alembert drew a
more general conclusion, and proved that the
curve might consist of several intermediate
branches, subject merely to certain conditions de¬
pending on the Theory of Partial Differences. The
solution of the problem gave occasion to a contro¬
versy between those illustrious philosophers, the
former maintaining that the portions of the har¬
monic curve might be discrete^ and the latter, in
conformity with the great principle of Leibnitz,
contending for their necessary continuity. But
Daniel Bernoulli, avoiding the mazes of intri¬
cate analysis and visionary metaphysics, gave a
clear investigation based on experiment. He
established from induction that a vibrating
string naturally divides itself into aliquot parts,
which perform independently their several os¬
cillations during each sweep of the whole chord.
Applying the same kind of reasoning to wind-
instruments, he showed that a cylinder of air
which, by its tremor darting in the cavity of a
tube with the rapidity of sound, produces its
fundamental note, divides, likewise according
to the force of intonation, into halves, thirds,
fourths, or fifths, which segments yield at the same
time their melting subordinate notes. Hence a
musical tone is never single, but consists in the
union and concord of certain elementary sounds.
And such is the origin of Music, which receives
its harmonious composition from the balance
and concert of Nature. The theory of Rameau,
which D’Alembert took the pains to expound,
is reducible to the same principle. Those acute
subordinate notes rise at times above the funda¬
mental, or outlive it. Hence the shrill expiring
note of a deep-sounding bell, and hence also the
narrow compass of the French horn, which
yields merely the successive natural tones ac¬
cording to the force of the blast.
These natural tones are derived from the mu¬
tual relations of the simple series of numbers 2,
3, 4, and 5. The ratio of 1 to 2 is evidently
compounded of the ratio of 2 to 3 and that of
3 to 4, and these ratios mark the sweetest con¬
cords. The interval between the | and | is g, and
between f and f it is which fractions indi¬
cate a tone and a semi-tone, the latter differing
from unit only by about half the difference of the
former. But | may be split into l, ^g, and
and hence § and ^g, though not quite equal, are
both deemed tones, the former being called the
Major and the latter the Minor. The fraction f
is therefore composed of |, |, T9g, and ; and
thus seven divisions, consisting of three tones
major, two tones minor, and two semi-tones,
fill up the whole extent of the fraction which
is hence termed the octave. It is impossible to
express an equal subdivision of ratios by small
numbers, but twelve semi-tones may be inter¬
polated with tolerable nearness. Speculative
authors have endeavoured to adjust or temper
the scale, and for this purpose they have some¬
times proposed the application of logarithms.
Wallis illustrated the Theory of Music with his
ingenuity and stores of erudition. In the ear¬
lier part of the subsequent century Malcolm and
Smith produced learned treatises on the subject.
But Euler himself, having at different times re¬
sumed the investigation, composed an ample
treatise on the General Principles of Music.
It is curious to compare the different degrees
of sensibility possessed by the organs of seeing
and of hearing. The eye extends its perception
over a range of intensity from one to beyond a
billion, or from the feeblest glimmer of twilight
to the dazzling glare of the meridian sun. But
it loses its grasp unless the impression lasts
nearly the tenth of a second on the sensorium.
Hence a momentary gleam of light, as in Elec¬
tricity, may elude observation, while a brand
whirled quickly round appears a continued cir¬
cle of fire.1 The discrimination of the human
ear has a more limited extent: It comprises
only eight octaves, from the gravest to the
sharpest note, or from those produced by only
16 vibrations in a second to those excited by a
succession of 8192 vibrations in that interval.
Such extreme rapidity might seem far beyond
the reach of our faculties; but it is the nature
of a musical note to repeat its action till an-
1 This remark might serve to elucidate the more recondite Electrical Theory. A variety of curious appearances are
explained from the same principle. Hence likewise the ingenious toy lately brought forward and called by Dr 1 aris the
Thaumatrojje.
DISSERTATION FIFTH.
729
other arises; and this divided duration, short as
it may he, is sufficient to impress the auditory
nerve.
The application of the Higher Calculus to un¬
fold the Motions of the Gaseous Fluids has ex¬
ercised the skill and ingenuity of the greatest
analysts, without producing however any mate¬
rial results. But what is really valuable has been
obtained, by the simplest theory guiding experi¬
mental research. One of the finest corollaries
drawn from the principles of Pneumatics is the
method of ascertaining the heights of mountains
by Barometrical observations. Pascal was the
first to propose this nice problem, after the
success of the famous experiment performed
at his suggestion on the summit of the Puy
de Dome. But the essential element of the
solution—the relation between the pressure and
the density of the air—had not been yet dis¬
covered. Twenty years elapsed till Richard
Townley, assisting at some of the experiments
which Boyle was making to refute the miserable
objections of Father Linus, perceived that simple
law, which the English philosopher confirmed
by other more extended experiments on the com¬
pression and dilatation of ah*. But in 1676,
Mariotte, a French experimenter, endued with
greater penetration, and possessing some geo¬
metrical skill, published a work on the Atmos¬
phere, of high merit for the time, and stamped
with originality. He had instituted a clear set
of experiments for investigating, and stated the
result in explicit terms, that the Density of the
Air is ahvays proportional to its Compressim.
From this law he sought to derive the graduat¬
ed rarefaction in the upper regions of the At¬
mosphere. He thought the variation of a line
by the barometer near the level of the sea should
answer to an ascent of 10^ toises, which is the
same in English measures as the tenth part of
an inch for 75| feet. He then proceeded to
find in succession the thickness of the strata of
air corresponding to 4032 twelfth parts of a line
in the whole mercurial column of 28 inches.
These strata he remarked might be found by
Logarithms; but contenting himself with a
rough computation, he adopted an arithmetical
instead of the geometrical progression. Hence
he reckoned the air to be 4032 times attenuated
at an elevation of 15 leagues or 43^ miles,
which is a tolerable approximation, the true
height being only 41J miles.
Mariotte had therefore no very distinct con¬
ception of the great property that at equal as¬
cents in the atmosphere the density of the air
diminishes in a continued proportion. This
beautiful theorem appears to have been first dis¬
covered and demonstrated about the year 1662
by Huygens, who never took the trouble, how¬
ever, to publish it.1 But in 1685, Halley gave
an elegant geometrical demonstration of the pro¬
perty, founded on the relations of the segments in¬
cluded between the hyperbola and its asymptotes.
For the sake of round numbers, he assumed 30
inches for the standard mercurial column, air at
the surface having 800 times less density than
water; and he made the elevation proportional
to the difference of the logarithms of these co¬
lumns, the interval between 30 and 29 inches
corresponding to 900 feet. This rule, drawn
directly from theoretical considerations, was
found to apply with tolerable accuracy to an ob¬
servation made a few years afterwards on the
top of Snowdon. Newton generalized the pro¬
blem in his Principia, by taking into the esti¬
mate the decrease of gravity in receding from the
centre of the earth, and arrived at the conclu¬
sion, that the densities of the higher strata of
the atmosphere form a geometrical progression
corresponding to the altitudes disposed in har¬
monic proportion. But this correction may be
deemed superfluous in most cases of barometri¬
cal measurement.
It was only wanted, therefore, to rectify the
method of Halley, by trying it with observations
made at great altitudes. But, for more than half
a century afterwards, the subject of barometri¬
cal measurement was entirely neglected in Eng-
1 The demonstration, with its date, is given on a Dutch Almanac, now preserved in the Library of the University of
Leyden, which, among other valuable notices, contains various microscopical observations, and a judicious parallel between
Descartes and Bacon, whom he censures for his ignorance of Geometry, his violent opposition to the Copernican System,
and his general inattention to the progress of physical and astronomical science.
D1SS. V. 4 Z
730
PRELIMINARY DISSERTATIONS.
land; and, instead of being improved on the
Continent, it had relapsed into confusion, and
became involved in hypotheses fosteied by the
lingering influence of the Cartesian philosophy.
Bouguer returned to the right path, and availed
himself of the opportunity afforded in surveying
the stupendous Cordilleras, to compare theory
with observations on the grandest scale. His
investigation was not published, however, till
1753, when he gave the very simple rule which
is the ground of all the modern practice : That
the difference between the logarithms of the barome¬
trical columns, reckoning as integers the first four
figures, and deducting a thirtieth part, will express
the altitude in toises. To accommodate the re¬
sult to English measures, it is only required to
add, instead of subtracting, the thirtieth part
of the logarithmic difference, to denote fathoms.
But still there were considerable discrepancies
which the ingenious observer endeavoured to
remove by some plausible suppositions respecting
the elasticity of the air. To find the density of
that fugacious fluid, he proposed an experiment
which marks originality of conception : It was
to note the relaxation of a pendulum or the rate
of its diminished sweeps at different elevations
in the atmosphere.
The chief cause of the perplexity was owing
to the variable influence of heat on the density
of the air. No further improvement could there¬
fore be made till that effect had been ascertained,
and the difference of temperature between the
stations in every case measured by the applica¬
tion of an accurate thermometer. De Luc has
the merit of reviving the subject, and of pur¬
suing his researches with ardour, skill, and per¬
severance. Geneva, his native city, from its po¬
sition near lofty mountains, afforded the great¬
est facility for conducting extensive observations.
He began his excursions among the Alps in
1754, and soon perceived the necessity of im¬
proving the barometer, and rendering it more
portable. By carefully boiling the mercury
within the tube, he was enabled to expel any
particles of air or of moisture which adhered to
its sides; and having adjusted the level of the
basin, he affixed to the instrument a scale mark¬
ed with fine subdivisions. But instead of fol¬
lowing the decimal division, and distinguishing
the inch into a thousand equal parts, he unfor¬
tunately took an irregular sequence, by adopting
lines or twelfth parts, which he broke down
again into sixteenths.
The construction of the thermometer engaged
his particular attention. He tried alcohol, and
various refined oils, and discovered their great
defects. He was therefore induced to prefer mer¬
cury, which, besides other advantages, he found,
by the methods practised by Renaldini and Brook
Taylor, to possess the essential property of ex¬
panding very nearly equally with equal acces¬
sions of heat. Substituting that mineral fluid for
the dilute spirit of wine, he merely corrected the
divisions of Reaumur, reckoning the arbitrary
number of eighty degrees from freezing to boil¬
ing water. Corresponding to each of these de¬
grees, he determined the expansion of air by
heat to be the 215th part, which answers to a
269th on the centesimal scale.
The rules which Deluc inferred from nume¬
rous experiments and observations were pub¬
lished in 1772 in his able but very diffuse work
entitled Recherches sur les Modifications de V At¬
mosphere. Two years afterwards they were re¬
duced to English measures, and simplified by
Maskelyne and Horsley ; and the problem of
barometrical measurement appears then to have
excited much attention in our island. General
Roy computed and observed the heights of
mountains in Wales, and Sir George Shuck-
burgh at the same time, and for a similar pur¬
pose, ascended the lofty summits of the Alps.
They had the advantage of employing barome¬
ters constructed by the celebrated Ramsden;
and their conclusions, published in 1777, ac¬
cordingly very nearly agreed, making the differ¬
ence between the logarithms of the mercurial
columns to express the elevation in fathoms at
a temperature only the fraction of a degree be¬
low the freezing point. Since that time little
more improvement has been effected, though se¬
veral circumstances that modify the solution of
the problem, especially the influence of humidity,
might require to be reconsidered. Laplace
indeed has introduced some niceties which ap¬
pear hardly suited to such imperfect data, and
render his formula extremely complex and in¬
elegant. Till the modifications of the atmos-
DISSERTATION FIFTH.
731
phere be measured with much greater precision,
we may rest satisfied with a simple and rapid
approximation. Nay, the application of loga¬
rithms might in most cases be superseded, by
employing a very easy proportion.1
The mutual appetency of the elemental atoms
includes both the cohesion of the particles of
a body to each other and their adhesion to a
different substance; and since this cohesive
force belongs alike to solids and to fluids, it only
preserves their volume, and does not essentially
maintain the firmness or figure of a body. Hence
the small detached portions of liquids run into
globules or drops, and hence also they may be re¬
tained in a vessel at some height above the brim.
In very narrow glass tubes, water and other li¬
quids will indeed stand considerably higher than
the level. This curious fact was first distinctly
noticed by Aggiunto, one of the leading mem¬
bers of the Academy del Cimento, who died at an
early age. But the completest series of experi¬
ments on Capillary Action was made by our
countryman Hauksbee. He proved that it is
not affected by atmospheric pressure, and suc¬
ceeds equally well in vacuo; he showed the
ascent of water and other liquids between prox¬
imate glass plates, and compared it with the
rise in narrow tubes; and he ascertained the
elevation to be always inversely as the width of
the bore or the separation of the plates. He
found the same property belongs to plates of
marble and brass, and remarked the ascension
of water in an open barometer tube crammed
with fine ashes. Dr Brook Taylor likewise
performed several ingenious experiments on
this subject: Having joined two plates of glass
at their vertical sides so as to form a sharp
wedge, he dipped it in a sheet of water, and ob¬
served the liquid to rise and form a rectangular
hyperbola; thus clearly exhibiting the relation of
the ascent to the interval between the proximate
surfaces. But he pursued the phaenomena of
corpuscular attraction still farther, and measur¬
ed the adhesion of a disc of glass to water and
mercury. Seventy years afterwards this in¬
quiry was resumed by the celebrated Guyton-
Morveau, who endeavoured to ground upon it
the chemical theory of Elective xAttraction. The
attempt however was fallacious, because the
force required to detach a disc of glass, marble,
or metal, from a surface of water or mercury, is
not a single effort, but combines the adhesion of
the liquid particles to the solid with their cohe¬
sion to each other.
In 1718 Dr Jurin, being led to examine the
phaenomena of Capillary Action, proposed a theo¬
ry for their explication which seemed at least
plausible. He rightly ascribed the rise of water
in the cavity of the tube to the close attraction
of the internal surface of the glass, though he
did not perceive the way in which that force
must act. He fancied the suspension of the
slender column of liquid to be caused by the at¬
traction of the ring of glass immediately above
the summit. But such an assumption was quite
illusory, for the ring below that limit would evi¬
dently exert an equal force in the opposite di¬
rection, and thus extinguish the influence of the
former. This singular oversight very long how¬
ever escaped remark, and Jurin’s hypothesis
became popular and commonly adopted.
Clairaut, discussing the equilibrium of fluids
in his famous work on the Figure of the Earth,
incidentally examined the property of Capillary
Attraction, of which he gave a profound but
incomplete analytical investigation. The acute
Segner took up the subject in 1754, and gave a
different solution, distinguished by its depth, in¬
genuity, and general accuracy. Assuming as a
principle, that the attractive energy is confined
to a mere exterior film of the liquid, he found
the curve of the upper surface to be what is
called the Lintearia, or the cavity of an inflated
sail formed by an uniform tension. The results
he obtained were perfectly accordant with the
pheenomena, except the figure of a drop, in the
determination of which he had, from overlooking
the double curvature, committed a small error.
Nearly half a century more elapsed till any
further attempt deserving notice was made to im-
1 As the sum of the mercurial columns is to their difference, so is the constant number 52,000 to the approximate height. This
number is the more easily remembered from the division of the year into weeks. For a condensed explication of the sub¬
ject of Barometrical Measurement, see Elements of Geometry, 4th edition, p. 454-456.
732
PRELIMINARY DISSERTATIONS.
prove the Theory of Capillary Action. In 1802, a
short dissertation on the subject, drawn up for a
particular occasion, and cast into a popular foi m,
was inserted in the Philosophical PLagazinc. It
set out from the simplest principles, refuted the
notion of Jurin, proved that the attraction of the
inner surface of the glass must be evei ted later¬
ally, and showed from the nature of fluids how
such a force would produce a vertical effort in the
liquid column. The author had designed to ex¬
pand the outline into a strict analytical investi¬
gation, that should embrace the whole range of
the phamomena, but deferred the task on account
of the more interesting objects which happened
then to engage his attention. This unpretending
essay, though little appreciated at the time, ap¬
pears however to have recalled the attention of
philosophers to a subject so long neglected. In
less than two years the late lamented Dr Thomas
Young resumed the investigation of Capillary
Action after the manner of Segner, and obtained
a very complete solution, but which required, be¬
sides, the admission of a repulsive force among the
particles of the liquid at a certain small distance.
At the mention of Dr Young’s name the historian
must pause. None of our countrymen has ap¬
proached more nearly to the character of the ce¬
lebrated Dr Brook Taylor. Possessing the same
ingenuity, extensive learning, varied accomplish¬
ments, and profound science, he combined like¬
wise a concise, hard, and sometimes obscure mode
of stating his reasonings and calculations. He ma¬
nifested some chagrin at seeing Laplace, within a
twelvemonth after, digress from the train of his
Mecanique Celeste, to produce an analytical inves¬
tigation of the phsenomena of Capillary Action, so
closely resembling his own in the general conclu¬
sions. The illustrious French Philosopher, over¬
looking the previous advances that had been made,
and little solicitous about tracing physical princi¬
ples, trusted to his consummate skill in the process
of calculation, and involved the subject in a maze
of intricate and abstruse formula. The reflections
drawn from Dr Young on that occasion were
extremely j udicious, and deserve to be held up
to view at present, when such a false taste pre¬
vails as threatens to involve the science of our
island in specious mysticism. “ It must be con¬
fessed that, in this country, the cultivation of the
higher branches of the Mathematics, and the in¬
vention of new methods of calculation, cannot be
too much recommended to the generality of those
who apply themselves to Natural Philosophy;
but it is equally true, on the other hand, that the
first mathematicians on the Continent have ex¬
erted great ingenuity in involving the plainest
truths of mechanics in the intricacies of Alge¬
braical formulas, and in some instances have even
lost sight of the real state of an investigation, by
attending only to the symbols, which they have
employed for expressing its steps.” [Lectures on
Natural Philosophy, vol. II. p. 670.)
Laplace’s intricate formula for Capillary Action
has been since unravelled by the acute discrimi¬
nation of Mr Ivory, who disjoined it into two
separate portions; the one depending on the ad¬
hesion of the watery film to the inside of the tube,
and the other resulting from half the cohesion
of the particles of the liquid to each other. But
our ingenious countryman deduced these ele¬
ments of the complete force from the simplest
physical principles, availing himself of the pro¬
perty of equable diffusion of pressure through
the mass of a fluid. The same investigation
gave the measure and limits of depression observ¬
ed in mercury and some other liquids. The
treatise on the Elevation of Fluids which first
appeared in the Supplement to this Encyclopae¬
dia2 was a masterly production, which fulfilled
every requisite that could be desired.
J In a memorandum bearing the date of December 1798, the principle is thus briefly stated: “ The attraction of water
to glass, being directed perpendicular to the surface, produces, in consequence of the laws of fluids, a lateral motion, in the
same manner as would the pressure of a vertical column equal to that force.” It then goes on to investigate generally the
curvature of the surface of the water, and gives the simple formulae jjd and for the ascent of that liquid between
glass plates or within the bore of glass tubes, the mutual distance or diameter being denoted in inches by d.
* Supplement to the fourth, fifth, and sixth editions, vol. IY. p. 309.
DISSERTATION FIFTH.
733
3. ELECTRICITY.
Elfxtricity has, from very small beginnings,
risen in the space of little more than half a
century to the rank of a Science, superficial in¬
deed, hut full of interest and splendour. With¬
out engaging the attention of profound philoso¬
phers, it owes its progress chiefly to the ardent
application of ingenious experimentalists. In
this department Hauksbee,1 a diligent and skil¬
ful operator, made some considerable advances
soon after the commencement of the eighteenth
century. He marked the circumstances of elec¬
trical attraction and repulsion, and observed the
production of light by friction both in air and
in vacuo. But to him succeeded a more fortu¬
nate explorer of Nature—Stephen Gray—a pen¬
sioner of the Charter House, a man of recluse
and peculiar habits, and no great reach of mind,
yet allured to the pursuit by curiosity and the
gleams of fancy. The apparatus he employed
was very humble, suited to his slender means.
About the year 1720 he gave a catalogue of bo¬
dies, which show electricity on being rubbed by
the hand, including most substances, except the
metals which he could not excite. But in 1732
he was led by a chain of accidents to discover
the conducting property inherent in certain bodies,
by which they are distinguished from such as
may become electrical. The fundamental facts
thus elicited were in 1739 arranged perspicu¬
ously by Besaguliers, who framed the inter¬
changeable epithets Conductors and Non-electrics,
and Non-conductors and Electrics, and proposed
the term Insulation to denote the interrupted
communication of electrical virtue. In the mean¬
while Dufay,2 keeper of the King’s Garden at
Paris, availing himself of these discoveries, ad¬
vanced in the investigation with a keener and
more philosophical spirit. Between the years
1733 and 1739 he detected two opposite kinds
of electricity, which he called the Vitreous and
the Resinous, the former being excited by rub¬
bing glass, crystal, and other kindred substances,
and the latter by the friction of amber, lac, rosin,
&c.; and he gave a clear view of the phsenomena
of electrical attraction and repulsion, by demon¬
strating that bodies similarly electrified mu¬
tually repel, while those dissimilarly electrified
attract each other.
Electricity began about this period to draw ge¬
neral notice, and accordingly more efficient means
were employed for the exhibition of its properties.
The friction of a glass tube or stick of sealing-
wax by the hand was abandoned for the adoption
of a large wheel to whirl swiftly a globe or cylin¬
der under the pressure of a cushion. Otto Gue¬
ricke had used for the same purpose a globe of
sulphur, and Haukshee one of glass; hut the ad¬
vantage of applying a cushion was not immedi¬
ately perceived. One or more gun-barrels sus¬
pended horizontally by silk cords, and having
small bundles of linen threads fastened to the
nearer ends, formed the prime conductors. Such
was the clumsy machine then constructed in
Germany, and thence introduced into France
and England. The curious found amusement
in drawing sparks and firing inflammable sub¬
stances; and experiments of that sort were in¬
geniously varied and multiplied. The analogy
of Lightning to the Electrical Flash could not
fail to be remarked, though their absolute iden¬
tity was not yet proved. Recourse was now had
to electric agency, for the mitigation or cure of
certain chronic disorders; and with that view
principally were different substances subjected
to its immediate influence.
The attempt to electrify water in a phial sus¬
pended by a hook from the prime conductor,
gave occasion at this time to a discovery which
constitutes an epoch in the annals of science.
The experiment appears to have been originally
performed in Poland, but was repeated in No-
A^ember 1745 by Cuneus and Lallemand at Ley-
1 Francis Hauksbee. Of this ingenious man, the best experimenter of his time, it is mortifying that so little should be
recorded. Neither the date of his birth nor of his death is known; but he flourished between the years 1709 and 1731, and
appears to have been Curator to the Royal Society of London.
a Born in 1698 at Paris, where he died in 1739. He was son of an officer in the French Guards, and had spent his
youth in the military profession, which he quitted for the study of chemistry and botany.
734
PRELIMINARY DISSERTATIONS.
den, and described by Mnsschenbroeck. It lienee
acquired the appellation oi the Leyden Phial or
Jar, and consists of a jar or plate of glass cover¬
ed or coated on both sides, to near the top or
edge, by a metallic leaf or other conducting sur¬
face, which renders it capable of holding a very
high charge of accumulated electricity. By this
wonderful invention, a power was obtained in¬
comparably greater than any former exhibition
of electrical influence. The shock or convulsive
agitation accompanying the discharge of a loaded
jar through the nervous system, at first inspired
terror, and still continues to excite surprise and
astonishment. The swiftness of electrical com¬
munication thus displayed seemed to exceed the
rapidity of thought itself. Nollet,1 a popular
lecturer on Experimental Philosophy at Paris,
sent the shock with instantaneous effect through a
whole regiment of guards; and Watson,2 an in¬
genious physician in London, could discover no
interval of time in its transmission by a circuit
of about six miles, formed partly by a wire, but
mostly by the course of the river Thames.
Various attempts were now made to explain
the electrical phaenomena. The ordinary class ol
philosophers had so long indulged the belief of
ethereal media, that they were easily induced to
ascribe the powers of electricity to the agency ot
such a subtile fluid, which might seem at length
revealed to our observation. Dufay showed that
the electrical machine draws its supply from the
ground, and Watson advanced a step farther, in
assuming that every substance naturally holds a
certain share of the fluid, which in a charged
jar is redundant on the one side and deficient on
the other, or distributed in a positive and negative
state. The credit of inventing this Theory has
been assigned to the celebrated Franklin,3 who
might probably without communication have hit
on the same idea, and is certainly entitled to the
merit of expounding it in a clear and interesting
manner. The shrewd American, without pos¬
sessing any superlative talents, or the advantages
of education, had, by industry, judgment, and
perseverance, raised himself to a conspicuous sta¬
tion in society. Having some tincture of science,
and a taste for experiments, he was peculiarly for¬
tunate in choosing a subject of inquiry which so
well accorded with the pitch of his acquirements.
He had repeatedly visited England, and after his
return to America he maintained a constant inter¬
change of letters with his friend Peter Collinson,
a wealthy grocer in London, but a zealous bota¬
nist, who valued learning, and held a regular and
extensive correspondence over Europe. Through
this channel of communication, was Franklin
early apprized of whatever chanced to engage
attention in the scientific world; and his obser¬
vations were in their turn quickly transmitted
across the Atlantic, and conveyed from England
to France and Germany. Having carefully
studied the important art of writing, he had at¬
tained a style remarkably simple and perspicu¬
ous, which gave the best effect to all his compo¬
sitions. His explication of the Leyden Jar, from
the redundancy and defect of a single fluid, was
favourably received both at home and abroad;
though the hypothesis of a vitreous and a resin¬
ous fluid, proposed by Dufay, and generally pre¬
ferred on the Continent, appeared to explain the
principal facts with equal readiness and facility.
But it was reserved for the American philo¬
sopher to complete a grander discovery, which,
though unreasonably extolled, is the foundation
of his permanent fame. The similarity of Elec¬
tricity and Lightning already struck several ex¬
perimenters ; and the Abbe Nollet had in ITJG
drawn a parallel, in which he compared the con-
1 John Anthony Nollet, born at Pimpre, in the district of Noyon, on the 19th of November 1700. From that obscure
retreat he was drawn by his growing reputation; and his amiable character secured the support and encouragement of
zealous friends. He had the advantage of visiting England and Italy, and those journeys procured him the favour of the
King of Sardinia, and afterwards the patronage of the Royal Family of France. Enjoying some appointments at Paris,
he for many years gave regular courses of Natural Philosophy, and by his popular and eloquent lectures, and his skill
in preparing and exhibiting the illustrative experiments, he spread a general taste for science. His elementary works,
without aiming at originality, are remarkably neat and clear. He died much regretted on the 24th of April 1770.
2 William Watson, born in London in 1715- Bred an apothecary ; and being very prosperous, he turned physician.
He was active and ingenious, with some talents, and still greater pretensions. By his ardour he extended considerably
the knowledge of Electricity. He died in 1787, having the year before obtained the honour of knighthood.
* Benjamin Franklin, born at Boston in 1706, and died at Philadelphia on the 17th of April 1790. His political career
is well known, and his literary progress has been sufficiently appreciated.
DISSERTATION FIFTH.
735
glomeration of thunder-clouds to the prime con¬
ductor of an electrical machine. Winkler next,
and with more decided arguments, contended for
the identity of those powers. Franklin, following
the same train of speculation, enumerated in a
clear and methodical order the different circum¬
stances of resemblance. But it was necessary to
pass the circle of mere probabilities, and he pro¬
posed as the final proof to have recourse to direct
observation. His suggestion wTas, to erect on the
top of some eminence a tapering iron rod 40 feet
high, which he conceived would attract electricity
from the charged thunder-clouds. Preparations
were accordingly made in France for trying that
bold experiment. In the spring of 1752, Dali-
bard, a distinguished botanist, had an iron rod 40
feet in height tied with silk cords to a post in the
neighbourhood of Paris, the lower end being pro¬
tected from rain by a sort of sentry-box. The ap¬
paratus was, during his absence, intrusted to the
charge of a resolute carpenter, who watching
the first appearance of a thunder-storm on the
10th of May, ran to the spot, drew sparks from
the rod, and, assisted by the curate of the vil¬
lage, actually charged an electric jar. The
demonstration of the nature of Lightning was
thus rendered complete; but an experiment so
wonderful deserved repetition. It was eagerly
performed, under the direction of Buffon, in the
Royal Garden at Paris ; and, during the months
of July and August, it was tried with the same
results near London, where Canton succeeded in
detecting atmospheric electricity by means of a
common fishing-rod.
Intelligence now came from America, that
Franklin had performed his experiment in a
finer style. Not having the opportunity of an
eminence in the flat country around Phila¬
delphia, he imagined the expedient of employ¬
ing a boy’s kite, to gain a great elevation in the
air. To the end of the hempen string, from
which hung a small key, he fastened a piece of
silk cord, for holding in his hand. On the 15th
of June in the afternoon, while a storm was ga¬
thering, he walked into the fields, and, assisted
by his son, he launched the kite, when, to his
inexpressible delight, he saw the loose fibres
stretch out from the string, heard a snapping
noise, and observed the pendant key not only to
attract light substances, but to give sparks on
approaching his knuckle. These were all deci¬
sive marks of electrical action, and answered his
most sanguine expectations. The success of
this trial encouraged him to entertain the daring
project of turning aside the stroke of heaven,
and of guarding our edifices from the ravages
of thunder, by the erection of lofty conductors.
These views, combined with amusing experi¬
ments and lively speculations, were explained
at great length, and in a very easy and pleasing
manner, in the series of letters to Collinson, and
through his friendship printed at London in
1755, and immediately translated into the French
language, and circulated with zeal and rapidity
over Europe.1
Notwithstanding the enthusiasm excited by
the dispersion of that work, the scheme of an¬
nexing conductors to buildings was yet slowly
adopted. The first one erected was by Watson,
at his villa near London, in 1762; two years
afterwards, they appeared in Germany; and not
till the year 1776 wrere they applied to pro¬
tect some cathedrals in Bavaria and Italy.
They have spread since in all directions, espe¬
cially on the Continent, flowing, it might seem,
with the tide of Franklin’s political celebrity.
But his famed hypothesis, if examined strict¬
ly, will be found to rest merely on the extension
of vague analogical considerations. If a pointed
wire sensibly draw electricity at the distance of a
foot from the prime conductor, through what a
wide range, it is argued, must a long tapering rod
shoot its influence in the vast magazine of the
atmosphere ! It may be shown, however, that
the point acts only on the electrified air which
streams from the machine, and by repelling
again laterally those affluent particles, facilitates
their continued flow. The slightest impediment
to the motion of the aerial currents reduces the
action of the point; while, on the contrary, a knob
or blunt termination may acquire the same in¬
fluence as a pointed end, if the flow of electrified
. 1 R deserves to be noted, that the Royal Society, which rarely extends its patronage to untried merit, had refused these
ingenious letters a place in their Transactions.
736
PRELIMINARY DISSERTATIONS.
air towards it be maintained, either by rendering
the ball very hot, or by sticking to it a small
lighted taper. The idea of stealing the lightning
from the thunder-cloud, and silently disarming
the fulminating agent, is therefore utterly chi¬
merical. To produce such an effect, the whole
body of succumbent air must discharge its elec¬
tric store, by actually coming in successive
contact with the end of the rod. And, in what
reasonable length of time could that extended
communication be accomplished? Butitisequal-
]y futile to suppose, that the terminating of the
rod by a point could have the slightest influence,
in tempting or leading the thunder-stroke towards
any particular spot. Yet such was the main
argument used in the famous dispute which once
agitated the scientific world, with regard to the
comparative advantages of terminating the con¬
ductors with points or with knobs.
But though any attempt to avert the course
of thunder seem preposterous, it is of extreme
importance to consider whether the intervention
of a proper conductor may not mitigate, or even
render innocuous, the fulminating stroke. The
coruscation of lightning resembles most the
electric spark, its tortuous path being marked
by the violent divulsion of the aerial track. The
rapidity of transit might indeed be regarded as
instantaneous; but Helvig has lately endea¬
voured, in Germany, to measure it by help of the
Camera Lucida, and estimates it, from probable
conjecture, at 8 or 10 miles in a second, or above
40 times swifter than sound. According to the
ingenious Gay-Lussac, lightning often darts at
once more than three miles in a rectilineal path.
The ordinaiy classing of conductors into per¬
fect or imperfect, is very loose and unsatisfactory.
Their true distinction consists in the time they
require, however short this may be, for the trans¬
mission of electrical energy. From a set of pecu¬
liar experiments, it would appear that the copper
transmits this virtue more than a thousand times
quicker than water, which again conveys it
several thousand times faster than dry stone.
But all the particles of the conductor are thrown
during the passage into a state of vehement re¬
pulsion, and, consequently, the disruptive effect
must be proportioned to the interval of action.
A copper tube, or ribband, of even moderate di¬
mensions, if well spread over the roof and con¬
tinued into the ground, may hence be sufficient
to protect a house from thunder, by reducing
exceedingly the duration of the repulsive efforts.
Iron, which is generally employed, conducts
twenty times slower than copper; and lead is still
worse adapted for the purpose, since it conducts
about a hundred times slower. The electrical
energy being conveyed chiefly along the surface
of bodies, sheet-copper should decidedly be pre¬
ferred for the substance of a conductor.1
Thunder-rods of the ordinary construction have
been now tried seventy years, and the accidents
from lightning seem just as numerous and in¬
discriminate as before. The public is gradually
losing its confidence, therefore, in the efficacy
of those vaunted protectors; but, in spite of such
warnings, philosophers are most unwilling to
descend from their proud eminence. When any
sinister event occurs, they are solicitous to find
excuses and parry objections. They recommend
the conductors to be planted nearer, carried
higher, and perhaps armed with a cluster of
points. It may require a few more of such fa¬
tal accidents as the late explosion, in France, of
a protected powder-magazine, to demolish finally
the Franklinian hypothesis.
But the injury caused by the stroke of light¬
ning is, in this climate, much less considerable,
after all, than has been generally believed. The
loss of human life by thunder-storms over Eu¬
rope appears not to exceed annually, perhaps, one
individual in three millions. The damage to
property from such appalling discharges is like¬
wise comparatively small. The ravages inflicted
on the Continent by showers of hail are of a
more formidable kind. Those frozen masses are
often large, and fall with such terrible force as
in the space of a few hours to tear in pieces the
vines and batter down the fields of corn over
wide and fertile districts. It was an object
therefore of still greater moment to mitigate,
if possible, the fury of such rageful storms.
1 On this important subject see a paper on Electrical Points and Conductors, in the first number of Professor Jameson’s
Philosophical Journal, published in 1823.
DISSERTATION FIFTH.
737
About the year 1776, several speculative expe¬
rimenters, conceiving electricity promoted con¬
gelation, and therefore the conversion of the
drops of rain into solid icicles, proposed erect¬
ing thunder-rods to prevent the formation of
hail. It was even suggested, in aid of those pro¬
tectors, to kindle fires on the high grounds, and
to shake the atmosphere by the discharge of
mortars. But Heinich showed the futility of
all such expedients, in a dissertation printed in
the Bavarian Transactions for 1785; and, except
the notice of a curious experiment by Seiferheld
in 1790, the question seems to have sunk into
oblivion. The attention of the public, however,
was again for a moment recalled in 1800, by the
offer of a prize from the Physical Society at
Berlin; but the successful candidates, Wrede
and Weiss, proved that hailstones had no con¬
nexion with Electricity, and that the various
expedients tried for averting them were entirely
fallacious. The subject seemed deservedly for¬
gotten for twenty years, but has been lately re¬
vived again by the periodical folly of mankind.
La Postolle, apparently a zealous visionary, pro¬
posed in France with the utmost confidence, as
a complete safeguard against the ravages of hail,
the erection of a tall wooden pole with straw
ropes hanging loosely from the top of it to the
ground. He was followed in 1823 by Thollard,
another projector equally sanguine. But as the
world is governed by names, the powerful talis¬
man or lofty thatched pole received the sound¬
ing, though not very classical, appellation of
Paragrele or Paragrandino. Certificates of its
efficacy flowed in from all parts; the storm-
clouds were seen by veracious witnesses collect¬
ing over those poles, and rolling their hail¬
stones harmless along the straw to the ground.
The cultivators of the mountain districts on the
confines of France, Switzerland, Italy, and Ger¬
many, seemed enchanted by the discovery, and
whole fields were planted with those Paragreles,
which, like embattled spears, dared the front of
heaven. The question relative to the utility of
Hail-Protectors was now referred to the Institute
of France; but that learned body, though it
clung to the charm of the Thunder-Rod or
Paratonnerre, rejected with scorn the pretensions
of the Paragrile. But the faith of the believers
was not so easily shaken, and a succession of
angry and querulous pamphlets for a while kept
up the dispute. Yet we may infer that the con¬
fidence in the efficacy of such notable protectors
is fast declining, since an old auxiliary—the agi¬
tation of the air by the firing of mortars—has
been recalled to their aid.1
In the latter part of the eighteenth century,
Electricity was enriched by a continual acces¬
sion of curious facts and experiments. New
instruments were devised, of nicer construc¬
tion, to measure the intensity of electrical at¬
tractions and repulsions. The catalogue of
electrics themselves was not only extended,
but rendered more definite, by distinguish-
ingThe opposite qualities of the substances rub¬
bed. Some steps have likewise been made
towards a more precise theory. If a ball elec¬
trified vitreously be approached to an insulated
cylinder, the nearer end will assume the resin¬
ous electricity, while the remoter extremity will
indicate the vitreous; the limit of neutrality al¬
ways advancing to the approximating ball. This
capital experiment appears to furnish the true
explication of the Leyden Jar. But it involves
a more extensive principle: Pressure may be con¬
sidered as only close apposition, and friction is
evidently a case of repeated pressure. Hence the
action of the Electrical Machine itself, and hence
likewise the theory of that beautiful contrivance,
the Electrophorus, first announced by Wilke of
Stockholm in 1762, but named and fully de¬
scribed in 1776 by Volta2 of Como, to whom
electrical science was afterwards so much in-
1 Orioli, professor of Natural Philosophy at Bologna, seems not disposed to acquiesce in the decision of the Academy of
Sciences at Paris. He appeals to the liberality and opulence of the French nation, and gravely recommends it to plant
paragr&les, armed with metallic wires about 40 feet high, and not more than 500 feet apart, over its wide territory; and
farther proposes that the experiment should be continued for ten years, under the inspection of some competent agricul¬
tural board. If the sum of 100,000 livres has been raised at his suggestion for that project in the small province of Bologna,
what might not be expected from the munificence of such a kingdom as France ?
2 Alexander Volta, descended of an ancient family in the north of Italy, and born in 1745. He embraced the clerical
profession ; but, devoting himself to the pursuits of natural science, he was appointed to the chair of physics at Pavia in
1774. Electricity engaged his attention, and the observations of Galvani opened to him that brilliant career of discovery
BISS. V. 5 A
738
PRELIMINARY DISSERTATIONS.
debted for its extension. The Vindicating Elec- resort, a number of horses, which, though stun-
tncity of Beccaria and the Returning Stroke of ned by the multiplied succussions, yet generally
Lord Mahon depend on the same property. Of recover and withstand those attacks, till the eels
a like nature is the accumulation of Electricity themselves become quite exhausted, and are
by the Doubler and other instruments of that dragged out helpless. It appears from dissec-
tion, that the Silurus Electricus is furnished with
It appears that the electrical state of bodies a very peculiar and complex nervous apparatus,
suffers a modification from every change of their which has been fancifully compared to an elec-
chemical or mechanical constitution. Such al- trical battery. But we are entitled only to in-
terations are detected by delicate Electrometers, fer, that the animal is endued with a faculty of
of which the best perhaps may he the gold-leaf one modifying, by sudden compression or otherwise,
proposed by Bennet in 1787. The origin of its internal constitution, and consequently its
atmospheric Electricity is finely illustrated by electrical condition.
that sensible instrument, which shows an evo- Electrical agency^ by effecting new combma-
lution or an absorption during the condensation tions among substances, has contributed essen-
of vapour or the transition of water into steam, tially to the advancement of Chemistry. Caven-
Hence a cloud suddenly collected from the con- dish discovered the composition of nitric acid in
globating vapours is vitreously charged, and 1788, bypassing successive sparks through a mix-
flashes its lightnings, which, by the succussion ture composed of certain portions of the oxygen-
of the air in their devious lengthened tracks, ous and azotic gases. By a similar process, he
conveyed to our ears with the tardiness of sound, found atmospheric air to consist of the same ele-
occasion the prolonged rolling noise of thunder, ments, only combined in a different proportion.
But his fine discovery of the composition of water
The power of benumbing the touch, which*be- was afterwards confirmed, by concentrating the
longs to a certain fish of the ray kind, thence effort of electrical repulsion, in the experiment
called the Torpedo, and very frequent in the Medi- that Dr Pearson, assisted by Cuthhertson, an
terranean, had been remarked from the earliest expert electrician, performed in 1799, which
times. This singular property was now sus- evolved those gaseous components. This sa-
pected to he owing to electrical influence; and tisfactory experiment has been since greatly
the zeal of Walsh in 1773 converted the con- simplified, by one of those happy miniature con¬
jecture into demonstration, showing by satisfac- trivances, in which the late very ingenious
tory experiments that the animal could send its Dr Wollaston so much excelled,
shock only through conducting substances. But Electricity can he transmitted through the
the power of stunning its prey is possessed in a several gases; and the light which it then extri-
much higher degree by a large species of eel, cates is brighter in proportion to the condensed
the Silurus Electricus, which was originally state of the medium. As the air becomes rarer,
brought from Surinam, and abounds in the the projected spark assumes a spieading lam-
pools and sluggish streams of the hot region of bent appearance, through all the giadations Oi
Venezuela. From a healthy specimen exhibited colour, from white to yellow, orange, and purple,
in London, vivid sparks were drawn in a dark- vanishing into the faintest violet. The moot
ened room. But from a rapid emission of shocks, copious display of purperine gleams appears
these animals suffer great prostration of strength; when the air is rarefied about 1000 times, which
and the celebrated Humboldt gives an amusing corresponds to an altitude of thirty-five miles in
account of the method of catching them in New the atmosphere. Such may he the proper region
Spain, by driving into the waters where they of the diffuse and tremulous coruscations of the
which will render his name immortal. Volta was particularly distinguished by the liberal and discerning patronage of
Napoleon. During the fervour of reform and revolution, he laid aside the ecclesiastical habits, ynd married; but, in the decline
of life, the early impressions regained their ascendancy, and compunction for the breach of the vow of celibacy preyed on
his spirits, and"undermined his health. He died on the 6th of March 1826.
DISSERTATION FIFTH.
739
Aurora Borealis, which is decidedly an electrical
phenomenon. If the rarefaction he pushed far¬
ther, the luminous appearance grows always
fainter, till it becomes extinct. Accordingly,
Morgan1 found by a very careful experiment that
an electrical charge is not conducted through a
Torricellian vacuum,—an important discovery,
since it shows that Electricity, like Heat, can
exist only in a state of combination with its re¬
cipient substances.
The close of the eighteenth century was dis¬
tinguished by the accession of a new branch of
Electrical Science, more brilliant and astonish¬
ing than even the parent stock. It originated
in a fortunate incident which occurred in the
year 1790. Galvani, whose name it bears, pro¬
fessor of anatomy at Bologna, remarked, in the
course of his demonstrations, that the limbs of a
dissected frog were strongly convulsed at every
spark which one of his pupils happened to draw
from the prime conductor of an electrical ma¬
chine standing in the immediate vicinity.2 Being
thus led to consider the subject, he made several
curious experiments, and published a Disserta¬
tion on Animal Electricity, which engaged very
general attention. The femoral muscles of a
frog, bared of their integuments, hut left connect¬
ed with the trunk of nerves, were found to serve
as a most delicate sort of electrometer. With this
aid, it was easy to trace the faintest vestiges of
electrical influence, and to contrast the proper¬
ties of various conductors. The very weakest
chemical solutions, the mere contact of different
metals, nay the apposition of animal fibres, were
all found in their several degrees to develope
electricity. But the simplest mode of exciting
it is, by the mutual application of small plates or
discs of copper and zinc. Dr Robison made a ca¬
pital improvement, in proposing a pillar of those
discs, like a rouleauof half-crowns, to augment by
their combination the intensity of effect. This
happy idea seems to have been overlooked, when
Volta in 1800 invented his famous Pile; the
most energetic instrument of all electrico-che-
mical analysis, and commencing deservedly a
new epoch in physical science. By Crookshanks
it was rendered far more commodious, in being
converted into the Galvanic Trough; which,
again enlarged into Batteries sometimes of enor¬
mous extent or dimensions, has conducted Davy,
Berzelius, and others, to the most splendid and
wonderful discoveries.
The Voltaic Pile is only a modification of the
Electrical Battery; but its peculiar action may
assume two distinct features. It either exerts
the slowness and duration of repulsive force, or
displays the most intense concentration of that
power. Hence the opposite effects produced by
very large single plates, and by a very numer¬
ous series of small ones. Light and heat are
most copiously projected from their recipients
by the former, while chemical decomposition is
effected with the greatest energy by the latter.
But it would require much patient and profound
investigation, to discover the working of such
recondite principles.
The original design of this discourse was to
come no lower than the early part of the present
century, and to avoid discussing the merits of
contemporaries. But I cannot resist the pleasure
of noticing the signal advance which Electricity
has lately made. Its close connexion, if not
perfect identity, with Magnetism had been long
suspected, and was even adopted by several in¬
genious theorists. This affinity found a most
zealous supporter in Ritter; but the fancy and
mysticism blended with his opinions had begun
before the year 1818 to weaken their influence.
In this state of uncertainty, Professor Oerstedt
of Copenhagen, happening, in the course of his
lectures during the winter of 1819-20, to show
his pupils the intense heat excited in a small
wire of platinum, laid horizontally and nearly
1 A very ingenious person, who died young, being nephew to Dr Price, and brother of the able Actuary of the Equitable
Assurance Company.
the Germans lay claim to the origin of Galvanism. Sulze, about the middle ot the eighteenth century, had, in his
work on Taste, noticed the singular impression made on the tongue by the contact of two distinct metals. But Zimmerman
as ktely produced a passage from the Biblia A aturaz, a book published at Leipsic in 1752 by Swammerdam, in which the
author mentions his having observed the convulsions of the muscle of a frog held against a glass tube by a silver wire
pendant from a ring of brass. Such facts are curious, and deserve attention ; but every honourable mind must pity or scorn
that invidious spirit with which some unhappy jackals hunt after imperfect and neglected anticipations, with a view of de¬
tracting from the merit of full discovery.
740
PRELIMINARY DISSERTATIONS.
in the direction from east to west, to join the
conductors from the copper and zinc plates of a
Galvanic Battery, thought of placing under it a
small compass, and the needle was observed in¬
stantly to turn aside as if it had been drawn by
another magnet. This surprising fact was not
much heeded by him at the time; hut having
afterwards carefully traced the conditions of the
experiment, he published near the close of the
year 1820 his great discovery, which awakened
the public attention, and gave rise to numerous
speculations that frolic in the giddy maze of
electric and magnetic currents.
It must indeed he confessed, that after all
the progress which Electricity and its younger
branch Galvanism have made, the hypotheses
commonly received are exceedingly vague and
unphilosophical. In cultivating these attrac¬
tive sciences, experimenters would seem to sa¬
tisfy themselves with the exercise of a looser
and humbler species of reasoning. It is rather
amusing to observe the complacency with which
some ingenious persons describe the play and
vagaries of an Electrical Current, whose exist¬
ence was never proved. We are acquainted
only with electric attraction and repulsion, and
with the transmission of electric influence : All
beyond these elementary principles, rests on
hasty conjecture. Instead of adopting one or two
fluids, it were safer to suspend the assumption
of any. We can perceive no distinctive marks
of the operation of a fluid, which is often con¬
founded with the mere luminous track occasion¬
ed by the particles of Light disengaged from the
substance of the conductor; the colour of emis¬
sion being modified by the peculiar character
and intensity of the retaining force.
The Theories proposed by ^Epinus and Caven¬
dish are entitled, however, to the praise of great
ingenuity, and may serve to connect with ele¬
gance the chain of principal facts. The latter
most accurate philosopher likewise stated the
immense disproportion in the celerity of differ¬
ent conductors, though he did not explain the
grounds of his conclusions. Coulomb agreed
with him in limiting electrical diffusion to the
surface of bodies; and the Balance of Torsion
showed the intensity of attractive and repulsive
power to be inversely as the square of the dis¬
tance. These were real discoveries, deduced
from nice and cautious observation; but his
countryman Poisson has since exercised profound
skill in the play of analysis, by attempts to ex¬
plore the hypothetical influence of Electricity,
without having arrived, however, at any con¬
clusion that is not obvious or of no value.1
4. MAGNETISM.
Nearly allied to Electricity is the science of
Magnetism. The property of attracting iron
possessed by a certain stone or metallic ore, was
known from the remotest times ; but the direc¬
tive power, or disposition to turn always to¬
wards the north, that most wonderful property
which guides the modern navigator over the dark
and desert expanse of ocean, lay hid through a
long succession of ages. This remarkable sub¬
stance derived its name among the Greeks from
Magnesia, a district of Macedonia, where it was
chiefly found.
The Magnetic Compass, with the art of dis¬
tillation, which was never practised by the an¬
cient Greeks or Romans, seems to have been
discovered in Upper Asia, and thence commu¬
nicated by their Tartarian conquerors to the
Chinese. From them again, the knowledge of
the invention spread gradually over the East.
The Crusaders, during the occupation of their
bloody conquests in those regions, had leisure to
admire the arts acquired by their more civilized
rivals. Having their curiosity thus awakened,
they appear, about the latter part of the twelfth
century, to have imported into Europe the
Compass, along with the substance which, mis¬
taking it for Natron, they called Salt Petre, and of
which they had learned the deflagrating property.
That invaluable instrument was at first very
rudely formed, consisting merely of a piece of
1 Such abuse of a noble science would have merited the censure of the Dunciad :
Or set on Analytic ground to prance,
Show all his paces, not a step advance.
DISSERTATION FIFTH.
741
the native mineral fixed to a broad cork, and
set to float in a dish of water. An artist of the
opulent town of Amalphi, the great emporium
of the East, and seated on the shore of Calabria,
in the direct route of the Crusaders, improved
the construction, and marked the north point by
a Fleur-de-Lis, the armorial bearing of the king¬
dom of Naples. From its directive property,
it was now called in English the Loadstone or
Leading Stone. About a century afterwards,
the method of communicating magnetism by the
touch was probably discovered, the needle or
small bar of steel so treated being then applied
to a card suspended on a pivot. The Germans
bisected successively the eight cardinal divisions^
which had satisfied the Romans and the Chi¬
nese, into sixteen and thirty-two points, to
which they gave those compound names which
are still retained. About this period, when ob¬
servations were not very precise, the needle was
judged to turn nearly towards the north; but
Columbus, in his first voyage of discovery, found
it to decline from the meridian as he advanced
on the Atlantic; and this apparent change of the
laws of nature occurred under circumstances
which would have appalled a less determined
commander. The variation ofi-the compass, how¬
ever, was distinctly noted in the year 1500 by
Cabot, another celebrated Italian navigator.
Magnetism made little further progress, till
Dr Gilbert, the founder of experimental science
in England, explored the subject by a course of
patient and skilful investigation. To this emi¬
nent philosopher we are indebted for the disco¬
very of the few connecting principles. Every
magnet, whether natural or artificial, has its
powers concentrated in two opposite points,
termed the north and south poles; and the si¬
milar poles of separate magnets repel each other,
while their dissimilar poles exert a mutual at¬
traction. When a piece of soft iron is approxi¬
mated to a magnet, it becomes itself a magnet,
the nearest end assuming an opposite polarity,
and therefore being constantly attracted. If a
long iron bar be held in a position nearly verti¬
cal, its lower extremity is always found to ma¬
nifest the properties of a north pole ; and, from
this induced power, Gilbert legitimately inferred
the magnetism of our globe. He likewise imi¬
tated its structure, by fashioning a magnet into
a small sphere or terrella, and hence illustrated
the declination of the needle, as well as its dip,
or the position which it takes when, after being
poised freely on its centre of gravity, it receives
the magnetic virtue,—a property which had been
first noticed by his countryman Robert Norman
in 1576. But something more was required to
explain completely the directive property of the
needle. If a magnetized sewing needle be set
to swim on the surface of water or quicksilver,
it will not advance towards the north, but readily
traverse in that direction. In fact, while the
one end is attracted, the other is equally repel¬
led, by the vast magnetic power of the earth con¬
centrated below the Arctic Region, but having
really the same quality as what was first named
the South Pole of the needle. Those antagonist
forces will have no influence therefore to draw
it forwards; but if it be turned aside, they will
combine their oblique action to bring it back
into its meridional position.
Gilbert’s original work Was republished at
Ferrara in 1629, with a commentary by Cabseus,
a Jesuit; and fourteen years afterwards another
member of that learned fraternity, Kircher, a
man of singular talent and immense erudition,
produced at Cologne a full treatise on Magnet¬
ism, which contained little* however, of sound
doctrine, but abundance of fanciful speculation.
Hooke remarked the debilitating effect of heat
on the power of the magnet. Newton appears
to have sometimes amused himself with mag-
netical experiments, but did not bestow much
thought on the subject: He was disposed to
consider the force exerted as reciprocally pro¬
portional to the cube of the distance.
The celebrated Halley, who, by his ingenuity,
learning, zeal, and enterprise, contributed so
largely to the promotion of physical science,
now turned his attention to the subject of ter¬
restrial magnetism. In 1683* and more dis¬
tinctly in 1692, he endeavoured to explain the
declination of the needle and its variations, by
supposing the Earth to be a hollow sphere with
two opposite magnetic poles, but having another
solid sphere, of analogous polarity, which re¬
volved slowly within it. From this bold hypo¬
thesis, of two fixed, combined with two mov-
742
PRELIMINARY DISSERTATIONS.
able poles, he sought to calculate the changes of
internal constitution that are continually going
forward. At a time when the method of find-
ing the longitude at sea was extremely imper¬
fect, he proposed the variation of the compass
observed in different latitudes, as an easy way of
obtaining at least an approximation to that im¬
portant problem. With this view it was neces¬
sary to collect numerous observations made at
remote points on the ocean; and in 1699 Halley
obtained the command of two small sloops of
war, with the rank of post-captain, the better
to insure subordination among the crews. Thus
equipped and empowered, he traversed the
vast Atlantic, diligently exploring both hemi¬
spheres, till he was arrested by the icy bar¬
riers. On his return in the following year, en¬
riched with a store of various information, he
published his Magnetical Chart, in which the
limits corresponding on the surface of the globe
to every five degrees of declination, were marked
by certain curve lines formed by connecting the
points of observation. This was the model of
all the charts of a similar nature which have
been since constructed. One of the most noted
was produced by Mountain and Dodson in 1744,
and again improved in 1756.1 Wilke laid down
another in 1772, and Lambert sketched out a
third in 1776. But the most accurate and com¬
plete magnetic chart that has yet appeared, was
published by Churchman in 1794. The value
of such delineations, however, is unfortunately
diminished by the errors proceeding from the
local attraction of the magnetic needle, which
were quite overlooked at that period.
Between the years 1712 and 1725, numerous
experiments were made by Hauksbee, Brook
Taylor, and Musschenbroeck, to determine the
relation of the intensity of magnetic force to the
distance of its action; but though the power ap¬
peared to decrease most rapidly with its remote¬
ness, no satisfactory conclusion was obtained.
The cause of this failure must he imputed to the
intermixing, in the statement of the results, no
fewer than four distinct forces, emanating from
the several poles. Taylor, the most acute of those
observers, reckoned the magnetic force, if exerted
very near, to be inversely as the square, but
when more remote, as the cube, of the distance.
It was reserved for Coulomb,2 sixty years after¬
wards, to discover the true law of magnetic at¬
traction and repulsion, by means of his delicate
Balance of Torsion, though the same deduction
had been previously announced by the ingenious
Lambert. The earlier experimenters had sought
to ascertain those forces by the loads required
to effect a separation, or to counterbalance their
action. Graham proposed the more precise me¬
thod of computing the magnetic forces, from the
number of vibrations performed in a given time
by the needle; but his suggestion was overlooked,
to be invented again, and generally adopted.
The properties of the magnet appear myste¬
rious, though reducible to a few primary facts.
But to discover the great pervading principle,
still baffles the ingenuity and penetration of the
most ardent research. The supposition of a
subtile permeating fluid is very generally em¬
braced, though it rather darkens than elucidates
the subject. Yet it seemed to receive counte¬
nance, from the curve lines marked out by iron-
filings when strewed on a sheet of paper or a
plate of glass laid over one or more magnetic
bars. On a hasty glance, these traces might be
regarded as indicating the circulation of an in¬
visible fluid. Euler, whose strength lay in the
command of analysis, went so far as to imagine
that the pores of the magnet were furnished
with a sort of valves, which permitted the en¬
trance of the current and prevented its return.
But this amusing experiment is most easily and
satisfactorily explained, from the composition of
the attractive or repulsive forces centred in the
magnetic poles. The curves delineated by the
filamentous chains, when two dissimilar poles are
exerted, resemble elliptical arcs, but seem hyper¬
bolic ones, if two similar poles unite their action.
The magnetic curve is distinguished by some
1 These laborious compilers in 1757 gave a table of no fewer than 50,000 observations arranged corresponding to the
years 17d0, 1710, 1720, 1730, 1744, and 1756. They found it impossible, however, to reduce all the changes to calculation.
2 Charles Augustin Coulomb, a most accurate and ingenious experimenter, was born at Angouleme in 1736, and died at
Paris on the 23d of August 1806. Receiving his education in that capital, he embraced the military profession, and was
sent as engineer to the island of Martinique. He afterwards held various employments, and might have risen to the highest
distinction, if he had been as compliant with the times as some others of his countrymen.
DISSERTATION FIFTH.
743
remarkable properties, and one of the most
beautiful may be cited : It is, that if from the
same points in the axis, tangents be drawn to
them, the several points of contact will range
in the circumference of a circle.1
iEpinus adopted the hypothesis of an active
fluid, to explain the phsenomena both of Mag¬
netism and Electricity, and endeavoured to re¬
duce its operations to great simplicity. Brug-
man and others have entertained similar notions.
But admitting the ingenuity of such conceptions,
they enable us merely to shift the difficulties.
We must imagine the constitution of the un¬
known fluid, while the properties of the magnet
itself are obvious to the senses. Sound logic,
therefore, dissuades us from indulging in dreams
hardly more instructive than the occult qualities
of the Schoolmen. The true business of the
philosopher, though not flattering to his vanity,
is merely to ascertain, arrange, and condense
the leading facts.
Ingenuity and patience were for many years
exercised in improving the art of constructing
artificial loadstones, or of communicating mag¬
netism by different modes of Touch. The ge¬
neral procedure depends on the magnetic power
induced by apposition, though it is often affect¬
ed by very slight circumstances, and always re¬
quires dextrous manipulation to insure success.
In France, Reaumur and Duhamel gave circum¬
stantial directions; hut our countrymen Knight,
Mitchell, and Canton, acquired peculiar address
in magnetizing; and iEpinus gave an improved
method, suggested by his theory, for communi¬
cating magnetism by the Double Touch, the two
rubbing bars being held each reclining about
half a right angle from the vertical position.
It was proved that the magnetic virtue resides
near the surface, and therefore hollow magnets
were proposed, though perhaps never actually
tried. But thin bars seemed to answer best for
attaching under the card of the mariner’s com¬
pass. Coulomb remarked that a steel wire is,
by twisting, made capable of being nine times
more strongly magnetized. It is singular that
cast steel is unfit for a magnet, and that the
smallest admixture of antimony destroys the po¬
larity of iron. In the years 1786and 1787, Cavallo
tried the magnetism of various substances, by set¬
ting them to float on a very clean surface of mer¬
cury, on which they turned nimbly by the smallest
force. In this way, he found that a trace of iron
which no chemical test could detect was yet ca¬
pable of sensibly affecting the needle. Nickel
is strongly magnetical, but seems enfeebled by
the addition of cobalt. Yet brass, though na¬
turally passive, becomes susceptible of magnet¬
ism by hammering, and loses this power again
when heated to near redness. But a more nu¬
merous and far more precise collection of expe¬
riments of that kind was made during the course
of twenty years, between 1784 and 1804, by
Coulomb. This most acute and accurate expe¬
rimenter found every substance almost to be
susceptible of magnetism. To examine the
property, he formed needles about three-eighths
of an inch in length, suspended by fine silk
lines; and these obeyed the magnet, though
composed of gold, silver, copper, lead, and
tin, nay of bone and chalk. But this seeming
universal diffusion of the property might still
be owing to the presence of iron, however
much attenuated. When bees-wax had incor¬
porated with it a portion of iron-filings equal
only to the 130,000th part of its weight, it was yet
sensibly affected by the magnet. Nor is it im¬
probable that nickel, as once believed, may be
only a refractory ore of iron, still resisting che¬
mical decomposition, though deriving from this
source its magnetic virtue.
The variation of the needle has been accurate¬
ly observed in Europe during nearly two centu¬
ries. It seems to be continually increasing,
though in a most irregular manner. In the
year 1657, it stood directly north at London;
and it held the same meridional position in 1660
at Paris. But during the remainder of the cen¬
tury it changed towards the west, at the rate of
IT annually at London, but only 6' at Paris.
From 1700 to 1725 the yearly increase of va¬
riation at London was only 9', from 1725 to
1750 it rose to 14'; but from 1750 to 1775 it
returned to 9' again, and from 1775 to 1800
it declined to 6\ For the next 25 years the
1 See Analysis of Curve Lines, near the end of the volume.
744
preliminary dissertations.
rate of augmentation has been scarcely 2, and
the change at Paris is still smaller. This
rapid decline of the annual change appeared to
intimate the needle’s approach to the limit of
westerly digression, from which it would slowly
return in the contrary direction. Such expecta¬
tion, however, is not yet realized. In 1817 the
needle was observed at Paris to make indeed a
slight retreat; hut, in the following year, it
moved forward again, and continues to advance,
though slowly, to the west. Its relaxation in
London is less apparent.1
But the variation of the needle, besides its
annual progress, is liable to other alternating
changes, amounting sometimes to a considerable
quantity. Its diurnal deviation was first re¬
marked by Graham in 1722, and ascertained
with more precision in 1750 by Wargentin of
Stockholm. But Canton investigated the sub¬
ject with great ability and perseverance, in a
very extended series of observations begun in
1756. He found the needle to travel westwards
from about nine o’clock in the morning till two
in the afternoon, when it remained for a while
stationary, and again slowly returned, regaining
its station during the night, or before the early
dawn. In the morning, its movements were
less regular. The extent of those digressions
was found to depend on the season of the year:
near the end of December, the diurnal aberra¬
tion was only 7', but it mounted to 13^' about
the middle of June.
Canton, with great probability, referred these
curious facts to the influence of heat on the
magnetic forces. Though the direction of the
needle is mainly determined by the internal
magnetism of the globe, it must also be affected
in some degree by the local attraction of the fer¬
ruginous particles united to mineral substances,
and profusely scattered on the surface. If we
suppose their joint power inclines to the east of
the magnetic meridian, it will evidently act
more feebly in drawing the needle aside during
the warm portion of the day, and in the height
of summer. This ingenious explication seems
to be corroborated by the observations made in
1794, on the island of Sumatra, by Macdonald,
who found the diurnal aberration there not to
exceed 3'. But the alternation of heat and cold
in that equatorial climate is likewise more li¬
mited.
The Dip of the Needle is much less change¬
able than its Declination. It is more difficult
to observe, but appears to have been diminish¬
ing during the last hundred years, at the very
slow rate of a minute annually. The quantity
of Dip, or the depression of a poised needle be¬
low the horizontal position, depends in every
place over the surface of the earth nearly on the
latitude. It would be very desirable to render
the observations with the Dipping Needle more
certain and delicate. Coulomb proposed an in¬
genious mode of computation, from the load re¬
quisite to bring it into an horizontal position
compared with the time of its vibrating in that
plane.
Albert Euler, son of the great analyst, cen¬
sured Halley’s magnetical hypothesis, and pro¬
posed in 1766 a simple theory deduced from ob¬
servations, and requiring the assumption of only
two poles, distinct however from those of the
terrestrial axis. The North Pole he would place
in the latitude of 75° 7', and the South Pole in
the latitude of 60° 37'; assigning to the former
a western longitude of 91° 54', and to the latter
only 38° 36'.
Biot and Humboldt, from a comparison of
later and ampler observations, assigned for both
the magnetic poles the opposite latitudes of
79° T; the longitude of the northern one being
27° 37', and that of the southern one 205° 12'
west from Greenwich. The plane perpendicu¬
lar to the magnetic axis intersects the equator
at an angle of 10° 59', and in west longitudes
117° 37' and 300° 27'.
But deductions of this kind are liable to a
source of inaccuracy which had long escaped
observation. The bolts and other pieces of iron
in the frame of a ship, ranging mostly before
the binacle, very sensibly derange the bearings
of the compass by their local attraction. This
deviation seems to have been first remarked by
1 The celebrated astronomer Burckhardt, by combining together a number of observations, has deduced a formula for
the variation of the needle at Paris. Admitting its accuracy, the maximum will be attained in 1837, and reach to 24° 26',
the period of magnetical revolution being completed in the space of 860 years.
DISSERTATION FIFTH.
745
Bayly, who accompanied Captain Cook as as¬
tronomer in the two last voyages of that great
navigator. But it was accurately investigated
by Lieutenant Flinders in 1795. The error thus
caused is often as much as 10 degrees; and,
owing to the oblique influence of terrestrial
magnetism, it attains to a much greater amount
in the high latitudes. When the vessel’s keel lies
in the magnetic meridian, the needle is not dis¬
turbed, and the divergence becomes greater in the
transverse position ; in every other position, the
sine of the deflexion has a certain ratio to the sine
of the angle of the course. A single experiment
will determine that ratio, and hence the rectifi¬
cation is easily applied. But Barlow has pro¬
posed a very simple contrivance, to avoid the
trouble of computation : It is to fix, on the deck
and immediately behind the binacle, a thin iron
plate, which by its proximity may counteract
the diffuse attraction along the forepart of the
ship. This adjustment being once attained,
must suit every situation.
But the action of terrestrial magnetism is evi¬
dently the result of its intensity combined with its
direction. Though the attractive force augxnents
in approaching to the magnetic pole, yet the Dip
of the Needle rapidly increases, insomuch that
the late Arctic voyagers found it in Baffin’s Bay
only three degrees from the vertical position.
The efficacy of the directive force was hence
reduced about nineteen times, and the compass
betrayed a deviation amounting to 70° or 80°.
The study of Magnetism, so long neglected,
has lately been revived with splendid success.
Conjoined with observations of the length of the
pendulum in different latitudes, experiments
have been likewise made on the oscillation of
the needle, which indicates the directive power
of the great internal magnet. From a compa¬
rison of these, it appears that the intensity of
the terrestrial magnetism is doubled in the
ascent from the equator to the western limit of
Baffin’s Bay. No person has shown such ardour
in pursuing the investigation of this subject as
Professor Hansteen of Christiania, who not only
with infinite labour collected and digested the
multifarious facts, but has undertaken distant
journeys for the purpose of rectifying former
observations. From all these combinations, he
DISS. V.
was enabled to detect the position of the mag¬
netic poles of the Earth, and trace the curves of
variation on its surface. But the results undergo
correction as often as fresh data are procured.
Hansteen infers, from experiments he made be¬
tween the years 1819 and 1826 on the oscilla¬
tion of the needle, that the magnetic intensity
has been decreasing annually at Christiania,
London, and Paris, by the 235th, the 725th,
and the 1020th parts respectively. This diver¬
sified effect he ascribes to the revolution of the
Siberian pole. '
The remarkable discovery of Oerstedt has
greatly enlarged the field of magnetic influence.
A wire of any kind of metal being laid horizon¬
tally and at right angles to the magnetic meri¬
dian, to connect the opposite conductors of a
Galvanic Battery, a needle either below or above
it is drawn considerably to the one side or the
other. Instead of bewildering the imagination
with the vagaries of invisible streams, a suffi¬
cient explication of the phsenomenon may be de¬
duced from two leading principles :—1. Magnet¬
ism is in some proportion diffused through all
metallic substances, owing either to their peculiar
constitution or the universal dissemination of fer¬
ruginous molecules : 2. The cross wire, from its
position with regard to the Terrestrial Magnet,
acquires induced magnetism, but extending trans¬
versely; the under side having the virtue of a
north pole, and the upper side that of a south
pole. The copious infusion of that virtue is
occasioned probably by the duration of the in¬
ternal tremor, excited by intense electrical ac¬
tion, and analogous to the effects on a bar of
iron or steel subjected to hammering, twisting,
heating, or the fulminating shock. Hence are
easily explained the diversified phases of attrac¬
tion, rotation, or impressed magnetism.
Arago proved that continuous electrical sparks
or discharges operate the same combinations as
the Galvanic Battery. But his penetrating in¬
genuity soon discovered the means of augment¬
ing prodigiously the intensity of the magnetic
action, by coiling the conjugate wire into a cy¬
lindrical spiral, and thus forming a sort of ma¬
gazine of transverse inferior and superior needles
which unite their influence. Schwegger, pur¬
suing the same ideas in Germany, has produced
746
PRELIMINARY DISSERTATIONS.
a very simple and convenient instrument, for
detecting the smallest traces of magnetic virtue.
Magnetism has again received a beautiful ac¬
cession from the keen glance of Arago, whose
mind embraces and enriches every department
of science. If a needle be finely suspended
over a thick circular plate of copper made to re¬
volve horizontally, it is drawn aside from the
meridian in the direction of the motion; and
when this becomes very rapid, it will even fol¬
low the tide of circumvolution. The effect is
nowise occasioned by the whirlwind raised, for
the experiment succeeds best when the needle,
pendant from a silk line, is inclosed within a
glass case that has a bottom of mica or thin
glass resting immediately over the plate of cop¬
per. The power is augmented by the proximity
of the needle and the thickness of the revolving
disc,—an evident proof of the attraction exerted
by the accumulated ferruginous molecules.
The simplest and most satisfactory way of
explaining this curious phaenomenon seems de¬
rived from the principle, that, though magnetism
acts instantaneously, a certain portion of time,
however small, is required for the infusion or
communication of the magnetic virtue. The
circular plate acquires this property from the
mere apposition of the needle; its axis with re¬
versed poles lying when at rest exactly under
the pointer. But if the plate he quickly turned,
the axis, not being instantly impressed, will be
carried forward, and must consequently draw
after it the needle, or even involve it in a con¬
tinued rotation. On the other hand, if the
copper remain fixed while the needle is made to
vibrate, the axis of induced magnetism must
always hang in the rear, and therefore retard, or
tend to diminish, and soon extinguish the oscil¬
lations. Hence an important practical inference,
that the needle of a ship’s compass should tra¬
verse near the bottom of a thick copper box, in
order to correct that excessive sensibility which
is so inconvenient in ordinary seamanship.
Magnetism has been gaining accessions like¬
wise in detail. Seebeck of Berlin proA^ed that
various substances have their magnetical state
affected by the unequal distribution of heat.
Becquerel described an instrument which, by
neutralizing the terrestrial influence, shows the
faintest shades of magnetism, and distinguishes
the slowest electrical conductors. His country¬
man Rousseau, advancing by the same path,
gave the construction of the Sideroscope, which
detects the very feeblest traces of iron in bodies.
This curious combination of magnetic needles
has been improved and successfully applied by
Leballif, who devotes the moments of respite
from the drudgery of a laborious office to the
ardent and unwearied pursuit of experimental
science.
5. OPTICS.
The science of Optics, next to that of Astro¬
nomy, is the noblest creation of human genius.
No branch of knowledge so far transcends ordi¬
nary notions, and none has more essentially
contributed to augment our perceptive powers
or expand the range of observation. The sense
of Touch, diffused with various intensity over the
surface of the body, connects us with the proxi¬
mate objects of an external world. Taste is akin
to Touch, and makes us acquainted with those
solvent properties of food which stimulate the
animal frame. The sense of Smell is not con¬
fined to mere contiguity, but extends its infor¬
mation to the substances which emit from a
distance their peculiar odorous effluvia. Hearing
carries our sensations still farther, and intimates
the operation and the direction of those distant
changes which excite the tremulous commotion
of sound in our atmosphere. But the faculty
of Vision is of a much higher order. It soars
above the grossness of matter, transports us
above this sublunary scene, and holds commerce
with the skies. The other senses have gained
no help from instruments, if we except the par¬
tial advantages which Hearing has derived from
the speaking and ear trumpets. But Sight was
refreshed by the application of Spectacles, and
its powers of exploration have been advanced in a
most astonishing degree by the tardy subsequent
discovery of the Microscope and the Telescope.
The wonders of atomic Nature seem now laid
open, and all the glories of the remotest celes-
DISSERTATION FIFTH.
747
tial forms are brought under immediate obser¬
vation. The medium of such intercourse is that
pure empyreal stream of Light, which approaches
the nearest to our conception of Spiritual Es¬
sence.
The chief properties of the rays of Light con¬
sist in Reflexion and Refraction. With the for¬
mer the ancients were sufficiently acquainted,
but they had only a vague notion of the con¬
nexion between the angles of Incidence and Re¬
fraction. It is somewhat singular that both the
Telescope and the Microscope should have been
several years invented before the law on which
their construction depends, or the constant re¬
lation between the sines of those angles, was de¬
tected. This important discovery was made by
Snellius, but simplified and first published in
1637 by Descartes, who greatly reformed opti¬
cal science. The progressive motion of Light
was next beautifully deduced from the annual
anticipation and retardation of the eclipses of
Jupiter’s satellites, by the ingenuity of Roemer,
a young Danish astronomer, who had been in¬
vited to France in 1672, and there liberally en¬
tertained for nine years, till he was recalled to
his native country and loaded with lucrative and
honourable appointments. One might suppose
that the aberration of the fixed stars, or their
apparent circular shifting in the heavens, would
have been hence anticipated, as a simple in¬
ference from the motion of Light combined with
the revolution of the Earth in its orbit. Such
a consequence had been foreseen by the acute
mind of Descartes, who therefore adopted the
instantaneous propulsion of light as a funda¬
mental principle in his Dioptrics. Were it
otherwise, he maintained the stars would not
appear in their true positions, and the sun
would be seen eclipsed long after his conjunc¬
tion with the moon. These considerations,
however, were quite overlooked, when Bradley
in 1729 established his fine discovery within
close limits, but on the very same grounds.1
Astronomers had been obliged to abandon
their attempts to construct telescopes of much
higher magnifying powers, and to contract the
apertures, and consequently to reduce the mea¬
sure of illumination in order to procure distinct
vision. Colour was still imagined to depend
merely on the various mixture of light and
shade. But Newton’s grand discovery of the
decomposition of the Solar Beam, first communi¬
cated to the Royal Society in 1671, and further
explained by his correspondence during the three
following years, changed the whole aspect of the
science. The ingenuity in devising the simple
and beautiful experiments with combined prisms,
is not more admirable, than the force and clear¬
ness of the reasoning which deduced from them
such splendid conclusions. The mild spirit of
the philosopher was wounded by the attacks of
petulance and contradiction; and he quietly re¬
tained, in his closet, for the space of upwards
of thirty years, the sequel of those invaluable
experiments, and only consented to publish the
Treatise of Optics after his reputation had final¬
ly triumphed over all opposition. This resolution
is much to be regretted, as it not only post¬
poned the diffusion of genuine science, but gave
occasion to the blending of some speculations
which the discerning author would probably not
have published in the high meridian of his in¬
tellect. Though the experimental procedure on
which the work rests had been strictly induc¬
tive, yet was the composition cast in a synthetical
form,—broken into a series of propositions, with
their preliminary apparatus of Axioms and De¬
finitions ; which commonly involve assumptions,
and so far from giving more precision to our
reasonings, imperceptibly lead to the admis-
1 In a letter of Descartes, bearing the date of 1634, he notices an experiment proposed by a Dutch correspondent, to prove
that Light takes a sensible time to arrive at the eye from a distance. This was to wave a tiaming torch at night, and observe
its reflexion from a mirror removed only a quarter of a league. The French philosopher with his friends repeated the
experiment several times, and could not discern the smallest interval between each bending of the flame and its reflexion.
But even admitting the lapse of the 24th part of an arterial pulse to intervene during the short passage to the mirror
and back again, or allowing the velocity of 46 English miles in a second, it would completely derange Astronomical Obser¬
vations. The sun would not appear in his real position, but in that which he occupied when the rays of light which reach
us began their journey. A solar eclipse would therefore be seen, not at the moment of conjunction, but an Hour afterwards,
the Light having to travel from the Earth to the edge of the Moon and back again, or to pass and repass the distance of
50 semidiameters, each of 3000 leagues.
748
PRELIMINARY DISSERTATIONS.
sion of errors. The very term Ref Tangibility,
which Newton, under the guise of a definition,
applied to the rays of light, became afterwards
a source of misconception. It evidently con¬
verted the refraction of light into a general pro¬
perty belonging peculiarly to the rays them¬
selves, and therefore independent altogether of
the quality or nature of the refracting medium.
This might appear only a slight distinction, but
it probably contributed to the hasty and inaccu¬
rate experimental inference, that in every case
the refraction of the mean ray by a prism deter¬
mines the corresponding refractions of the ex¬
treme rays, or that the solar spectrum is always
distinguished into the same proportions of co¬
loured spaces. Since all material action, how¬
ever, is reciprocal, the refractive process cannot
be referred to the single agency of the particles
of Light, but must result from their mutual at¬
traction to the substance of the transparent me¬
dium. It is not the lot of humanity to reach
perfection, and the most gifted of mortals will
at times betray the weakness of our nature.
The subdivision of white light into seven com¬
ponent rays, and the distinction of the spectrum
into coloured spaces adapted exactly to the in¬
tervals in the diatonic scale of music, were no
doubt fine illusions which reflected the mys¬
ticism of the age. But it must now be ad¬
mitted that the primary colours melt into each
other by imperceptible shades, and that the spec¬
tra painted by different prisms differ widely in
their relative extent, and exhibit even a diver¬
sified partition of spaces.
Certain it is that the philosophers on the Con¬
tinent generally refused to admit the accuracy
of the conclusions of the Treatise of Optics, and
Mariotte, the most ingenious and skilful of the
French experimentalists, was unsuccessful in his
attempts at the prismatic decomposition of the
sun’s rays. His failure must no doubt be attri¬
buted to the influence of prejudice, and the stiff¬
ness of advanced age ; but finally to silence all
such opposition, it was judged expedient in 1716
that Besaguliers should repeat and somewhat
vary the original experiments before a committee
of the Royal Society at London.
Notwithstanding these few blemishes, arising
merely from hasty generalization, the Newtonian
Theory of Light and Colours is undoubtedly one
of the noblest efforts of human invention. It
quickly modified the projects of opticians. The
imperfection of the Telescope was hence found
to proceed only from undue mixture of colour
in the image, occasioned by unequal refraction,
which no change in the forms of the glasses
could remedy. The Reflexion of Light alone
offered any chance of improvement. Newton
had constructed a small Catoptrical Instrument
with his own hands; but for many years after¬
wards no artist appeared that possessed sufficient
skill to imitate and improve it. The ingenious
Mr Hadley in 1723 was the first who succeeded
in getting a Reflecting Telescope made for his
private use; and we may presume that the great
inventor himself, before the close of life, enjoy¬
ed the satisfaction of seeing his early ideas rea¬
lized. Such was not the fortune of James Gre¬
gory, whose Reflector, more complex indeed, but
likewise more commodious, had remained a mere
speculation, till about this time it was manufac¬
tured and came to acquire high reputation. James
Short particularly distinguished himself by the
finished execution of those instruments, and for
a long time he maintained the superiority of the
English artists. Every improvement in the con¬
struction of the telescope contributed to the ac¬
curacy of astronomical observations.
Hadley not only gave an impulse to practical
astronomy, but soon enriched its stores by that
invaluable instrument the Quadrant of Reflexion,
which has ultimately produced a complete revo¬
lution in the art of observing. A similar instru¬
ment was proposed by Newton as far back as the
year 1669, in consequence of an unsuccessful
attempt of Hooke; but the description had been
laid aside and neglected till 1731, when the an¬
nouncement of Hadley’s invention recalled it
from oblivion. The mode of finding an altitude
hitherto practised at sea was liable to much
uncertainty, since it required to direct the eye
first to the horizon and next to the disc of the
sun, though the instrument might have its posi¬
tion altered during this interval by the motion
of the ship. The difficulty was now obviated by
employing a movable index, which brought the
sun’s image to touch the boundary of the horizon.
It is a very happy application of the simple prin-
DISSERTATION FIFTH.
749
ciple in Catoptrics, namely, that a ray of light
which has suffered two reflexions deviates from
its course by an angle just double of the mutual
inclination of the mirrors. The Quadrant was af¬
terwards enlarged into a Sextant, it had telescopic
sights affixed to it, and received its final simpli¬
fication in this country from the dividing engine
of Ramsden. This delicate instrument has come
since into almost universal use in measuring
angles; and though originally contrived only to
observe the latitude at sea, it is now employ¬
ed with the greatest facility in ascertaining the
angular distance of the moon from the sun or a
star, and thence supplying correct data for com¬
puting by the help of improved lunar tables the
longitude itself.
Meanwhile the Sextant underwent a radical
transformation on the Continent, being changed
into an entire Circle. This was effected by the
celebrated Mayer, whose very narrow circum¬
stances drew forth all the resources of his inven¬
tion. He sought to remedy the imperfection of
the common Graphometer or Circumferentor,
by multiplying the angle observed, and thus
blending and extenuating the errors of subdivi¬
sion. By this simple contrivance not only were
the grosser inaccuracies obviated, but the instru¬
ment was rendered even superior to others of the
finest construction. Mayer next conjoined this
principle with that of Hadley, and produced the
Repeating Circle, which, having afterwards re¬
ceived some further improvements from Borda,
is now employed universally on the Continent
in Goniometrical Surveys, and in the practice
of Navigation and Astronomy. This instrument
being complex, however, in its construction, and
tedious and operose in its application, seems after
many trials not to be gaining ground in Eng¬
land. Its chief advantage consists in reducing
the errors occasioned by imperfect workmanship,
which a more skilful execution might nearly pre¬
clude.
The middle of the eighteenth century was dis¬
tinguished by a capital correction of the New¬
tonian principle of the proportional refraction
of the several rays of light, which has led to the
most important practical results. It had been
concluded that no combined unequal refractions
could ever form a white image, because the same
refractive powers which might neutralize the
colours must likewise bend the converging or
diverging rays into exactly parallel directions.
But, dissatisfied with this theory, Euler in 1747
endeavoured to prove the possibility of destroy¬
ing the coloured margin of a focal image, by imi¬
tating the structure of the eye, which he con¬
sidered as a perfect optical instrument. He pro¬
posed to construct a convex lens, by joining two
meniscus glasses holding water in their cavity;
and expected from such a combination not only
to correct the spherical aberration, but to pre¬
vent the border of colour. All his attempts,
however, to obtain distinct vision, were unsuc¬
cessful. Yet he still persisted in holding it to
be a Law of Nature, that not the refractions of
the extreme rays, but the indices of their powers,
are constantly proportional; and from this ma¬
thematical or metaphysical assumption, he strict¬
ly deduced his calculations. These speculations
of Euler made some noise in the scientific world,
and shook the confidence abroad in the accuracy
of Newton’s experimental conclusions. About
this time John Holland,1 bred a silk-weaver, the
trade of his father, a French Protestant refugee,
being fond of mathematical studies, had chosen
to embrace, in partnership with his son, the pro¬
fession of an Optician, as more congenial to his
taste. Having already acquired reputation for
ingenuity and skill, he communicated in 1752,
> John Dolland, born in Spitalfields in June 1706. Left by the early death of his father in straitened circumstances, he
was obliged to toil for the support of the family. But his thirst after useful knowledge led him to devote every spare
moment to private study, and even to encroach on the hours of repose. By such severe application he made considerab e
proficiency in geometry and algebra, in optics and astronomy, and added to these attainments a tolerable acquaintance wit i
the ancient languages. He became anxious to follow a profession better fitted to his genius, and in 1752 hejoined his son
Peter, who having quitted silk-weaving, had successfully commenced the business of optician. The discovery of achro¬
matic glasses in 1758 established his reputation, and afforded a prospect of the large fortune afterwards reaped by the indus¬
try and perseverance of his successor. But the elder Dolland had only begun to taste the sweets of prosperity: while en¬
gaged intensely in the perusal of a new memoir of Clairaut, he was, on the 30th November 1761, struck with a fit ot apo¬
plexy, which in the space of a few hours hurried him to the grave.
750
PRELIMINARY DISSERTATIONS.
to the Royal Society of London, a short paper,
showing that the principle advanced by Euler
was discordant with the property deducible from
the Newtonian experiments. But it did not
thence follow that either of these must be the
true Law of Nature; and accordingly Klingen-
stierna, an ingenious and learned Swedish philo¬
sopher, proved that the hypothesis espoused by
Dolland would not stand a rigorous analytical
investigation. The English artist was therefore
compelled to adopt the only sure and decisive
mode of settling the question, the unbiassed
appeal to experiment. He soon found that his
preconceptions were inaccurate, and that refrac¬
tion may subsist without any fringe of colour.
He formed a wedge or hollow prism with two
thin rectangular pieces of plate-glass, joined at
the edges and cemented to planes of brass at the
ends, and having filled the cavity with distilled
water, he inverted in it an acute-angled glass
prism, and looking through this compound me¬
dium, he gradually widened the angle of the
glass plates, till an object placed in front ap¬
peared free from any coloured border, but con¬
siderably depressed. The refraction of the
water had therefore predominated over the op¬
posite refraction of the glass, without expand¬
ing at the same time the prismatic colours.
This simple and well-devised experiment esta¬
blished therefore, in contradiction to Newton,
the important principle, that the length of the
spectrum, or the dispersion of the extreme rays, is
not always proportional to the mean refraction,
but depends on the constitution of the diaphanous
medium. The result already indicated an im¬
proved construction of the telescope, by substi¬
tuting a compound object-glass, inclosing water,
nearly in the manner attempted by Euler. But
Dolland rejected this imperfect expedient, and
sought to produce an unalterable combination
with different kinds of glass: Having struck
into the right path, he pushed forward to a great
discovery. He tried to select among the dif¬
ferent kinds of glass such as might effect his
purpose; and after a long and perplexing re¬
search, he finally preferred the combination of
crown and flint glass; the refractive power of
the former being to that of the latter as two to
three, while their opposite dispersions are equal.
A convex lens of crown glass of the focal length
of two feet, conjoined with a concave lens of
flint glass having a virtual focus at the distance
of three feet, must hence form a colourless image
at the distance of six feet. This capital dis¬
covery, achieved in 1757, enabled Dolland to
construct refracting telescopes of much larger
aperture and wider field than before, and pre¬
senting the image with such a pure brilliancy as
to entitle them to the name of Achromatic. It
was likewise possible to correct the spherical
aberration by modifying the coalescent curva¬
tures. But the discharge of extraneous colour is
attained most completely by forming a triple ob¬
ject-glass, composed of a concave lens of flint
glass inclosed on both sides hy two convex lenses
of crown glass.
The theory of Achromatic Telescopes was now
complete, but it still required patience and ad¬
dress to carry it into successful execution. Dol¬
land, and his son afterwards, took incredible
pains in choosing their samples of glass, and ac¬
quired such exquisite skill in combining them,
as to set all rivalship at defiance. The Conti¬
nental Mathematicians were eager in examining
the structure of those achromatic lenses, and in
applying their superlative powers of calculation
to define the proper forms. Klingenstierna and
Boscovich, hut especially D’Alembert and Euler,
distinguished themselves by their most elaborate
and profound investigations in this new branch of
Dioptrics. Yet it maybe questioned whether art¬
ists have derived any real help in practice from
such vast and profuse displays of analytical re¬
search. England, following a more tentative pro¬
cedure, continued exclusively for half a century
to supply the world with Achromatic Glasses.
The correction of colour obtained by the in¬
genuity and perseverance of Dolland consisted
thus in the blending of a spectrum with an¬
other of the same reversed length, but caused
by an inferior refraction. Though the extreme
boundaries were necessarily white, it did not
however follow that the intermediate portions
should be absolutely colourless. On the con¬
trary, it seems ascertained that not only the en¬
tire expansion of the spectrum, but the relative
extent of its several coloured spaces, depend on
the peculiar quality of the refracting medium.
DISSERTATION FIFTH.
751
A redoubled combination of lenses might there¬
fore mingle and destroy the secondary colours
scattered through the middle range. But the
light would be necessarily enfeebled by suffering
those rej3eated refractions.
Several experimenters, in their attempts to im¬
prove the achromatic telescope, had proposed the
interposition of fluids between the pieces of the
compound object-glass. But the late Dr Robert
Blair instituted the most elaborate investigation
on this subject about the year 1787. He found
all the essential oils, hut especially certain me¬
tallic solutions in muriatic acid, to possess the
greatest dispersive powers. A most compli¬
cated arrangement of those fluids with different
lenses was first tried, and next abandoned for
a less intricate combination of a triple muriatic
solution, inclosed in glass shells, and invested
on both sides by a semiconvex and a meniscus of
crown glass. This compound appeared to pro¬
duce the effect desired, not only discharging
from the image the extreme fringes of red and
violet, but excluding also the intermediate streaks
of green and yellow. Unfortunately the liquid
by degrees lost its transparency, either from the
change of its own constitution or from the slow
but continual corrosion of the surface of the
glass. A similar attempt has been lately reviv¬
ed, but we fear with no better prospect of suc¬
cess. No confidence can be placed in the per¬
manent transparency of any fluid medium.
Although the prismatic colours follow the same
invariable order, they yet expand in very differ¬
ent proportions, according to the nature of the
refracting substance. It is impossible, from the
closest examination of the solar spectrum in a dark
room, to distinguish the limits of the several co¬
loured spaces, which appear to melt away by in¬
sensible gradations. The extreme boundaries of
illumination are still more undefined. The red
seems to graduate near the edge into a dull brown,
while the violet spreads out by lengthening shades
into blackness. Those verges are no doubt more
extended in our climate, owing to the greater
profusion of lateral rays sent from the white por¬
tion of the sky which encircles the sun’s disc.
Three primary colours—red, green, and vio¬
let—are commonly supposed to be sufficient by
their various admixture to generate all the rest.
Thus, red mingled in different proportions with
green produces orange or yellow, and green
suffused with violet gives blue; while red blend¬
ed with violet forms crimson, that fine brilliant
hue which is not emergent in the solar spec¬
trum. In this pencilled expansion, we may
thus reckon three principal colours, or more
completely four, five, or six, with innumerable
shades. If the whole extent of the spectrum
produced by a prism of flint glass be reckoned
50 parts, the spaces occupied by the unfolded
colours will be nearly represented in this series :
red 5, orange 4, yellow 7, green 9, blue 10, and
violet 15; or if the orange be merged in red,
and the yellow in green, the expanse of the four
resulting colours will be, red 9, green 16, blue
10, and violet 15. These successive spaces are
all considerably different, it must be confessed,
from the fanciful subdivision of the diatonic
scale of music attributed to the range of the
spectrum formed by water or crown glass.
It is often assumed that the numbers of the
component rays of light are proportional to the
breadths of the several coloured spaces of the
spectrum. But the most ordinary experience
contradicts that supposition; for the eye is of¬
fended by the excessive glare of red and orange,
is relieved by the softness of green, and feels
languid under the feeble action of blue or violet.
Whatever may be the distinctive properties of
the coloured particles themselves, they are evi¬
dently collected by the prism in groups of very
different densities. It is hardly possible to com¬
pare the various intensities of such heterogene¬
ous things as colours with any degree of precision;
but when highly condensed, the impression they
make on the eye is nearly the same as that of
white light itself. On this principle the late inge¬
nious Fraunhofer, the great improver of achro¬
matic glasses, was enabled in 1814 to estimate
nearly the illuminating powers of the prismatic
rays, by examining them as concentrated in the
field of a large telescope of a theodolite. He
found the brightest spot on the spectrum of flint
glass to lie on the verge of the yellow next the
orange, and about 11 parts of its whole extension
of 50, from the extremity of the red. But the
most remarkable discovery he made was, that
though the coloured spaces appear not parted by
752
PRELIMINARY DISSERTATIONS.
any distinct boundaries, yet they are broken and
subdivided by numerous white and black lines,
or even dark stripes. He reckoned altogether
above 600 lines; a few occur in the red, but
they are multiplied in the orange, the yellow, the
green, and the blue. A stripe, opened by a fine
white line, divides the red; other stripes emerge
at intervals between the orange and the blue;
and two very broad approximating bars cross
the violet. Other glass prisms, and even those
filled with liquids, gave similar appearances,
which were therefore not accidental, but the
constant results of some law of nature. The
powers of refraction thus advance not by insen¬
sible gradations, but seem to ascend with irre¬
gular bounds. This inference bears some ana-
]ogy to the Newtonian hypothesis of the easy fits
of reflexion and transmission.
The same judicious philosopher, combining
eminent practical skill with deep and accurate
science, succeeded by unwearied application in
achieving the grandest improvement effected in
the construction of achromatic glasses since the
time of Holland. Fraunhofer conducted per¬
sonally the whole train of a large establishment;
he directed the preparation and fusion of the
materials, selected the proper pieces for grind¬
ing, and prescribed the due forms. The glass
produced under the patronage of the liberal
Bavarian government greatly surpassed in qua¬
lity every other kind: It had a translucid pu¬
rity, and a uniform consistency. Fraunhofer
constructed with it the most perfect object-lenses,
of more than eight times any former dimension,
and exceeding nine inches in diameter. He had
proposed to attain an aperture of ten inches or
even more, and would unquestionably have suc¬
ceeded, if death had not prematurely stopt his
ardent career. The power and brilliancy of such
magnificent telescopes transcended all concep¬
tion. 1
If the rays of the coloured spaces of the spec¬
trum be so widely diversified in their illuminat¬
ing energy, they differ no less in the property
of exciting or communicating heat. Common
language betrays in this respect their distinctive
characters. Red and orange are termed warm
colours, green temperate, and blue and violet are
said to be cold. The first that endeavoured to
measure the heating powers of the coloured rays
of the spectrum was the Abbe Rochon, who in
the summer of 1776 employed for that purpose
an air thermometer and a prism of flint glass.
But though he used some precautions, and re¬
peated his experiments, the results were not
very nice or consistent. Without venturing to
compare the calorific intensities of the extreme
rays, he yet reckoned those of a bright red as
about eight times more powerful than such as
gave the liveliest violet, and considered the bor¬
dering orange as the hottest spot in the spec¬
trum. But in this country the differential ther¬
mometer, modified as a photometer, being an
instrument susceptible of incomparably more
precision, was applied to the spectrum of flint
glass in 1798. Dividing the whole extent into
four equal spaces, the calorific energies of blue,
green, yellow, and red might be represented
with tolerable exactness by the series of square
numbers 1, 4, 9, and 16. Two years after¬
wards the famous Dr Herschel tried to measure
the impressions made by the coloured rays on
the small bulb of a mercurial thermometer, and
arrived at the paradoxical conclusion, that the
hottest part lies even on the outside of the red,
and at a little distance beyond the extr eme ter¬
mination of the spectrum. It was thence in¬
ferred that there are dark rays which give only
heat and not illumination, and travel in com¬
pany with the solar beams, though less sub¬
ject to refraction. This bold hypothesis was for
a time regarded with wonder and applause; but
the delicate observations of Berard, by the help
of an Heliostate to direct the incident rays and
give them a steady effect, soon demolished the
fabric. A large circular prism or the outer-
ring of a huge burning glass has been since em¬
ployed to mark with nicety the limit of the
1 The Bavarian flint-glass appears free from those wavy lines or streaks which still impair the hest English specimens,
and displays besides one-third more of dispersive power. The famous telescope constructed for the University o orpa
has an aperture of 9^ inches, with a focal length of 14 feet 3 inches English measure: it turns with a double parallac ic mo¬
tion, guided by the constant revolution of a centrifugal pendulum. This wonderful production of art, pouring a ooc o
light on the image, magnifies 200 and occasionally 600 times, and has enabled Professor Struve to augment prodigious y
the catalogue of double and changing stars.
DISSERTATION FIFTH.
753
greatest calorific effect, which always occurs
within the red space, though nearer its exterior
border. The notion of dark rays of light, which
enveloped the science in mystery, stands now
therefore without any proof, and is utterly dis¬
countenanced by sound philosophy.
The improvements made in the application
of Optics to the measuring of angles, since
the invention of the repeating circle, relate
principally to the micrometer. Bouguer pro¬
posed his Heliometer, or double object-glass
micrometer, in 1748; but Short and Dolland,
probably from a different suggestion, simpli¬
fied the contrivance in 1754, by dividing a
single object-glass into two equal portions.
Beccaria had shown that rock crystal, like Ice¬
land spar, has the power of double refraction;
and Rochon availed himself of this property to
construct in 1777 a very delicate micrometer,
though Boscovich about the same time appears
to have conceived a similar idea. Dr Maske-
lyne had more than a year before pursued a
path little different, his micrometer consisting
of movable glass prisms.
The French have ingeniously directed the
principles of Optics to the improvement of
Light-Houses. In this useful pursuit the cele¬
brated Buffon led the way. Endeavouring to
realize the performance ascribed to Archimedes,
he disposed 400 mirrors, each of them half a
foot square, into a frame, so as to collect the
sun’s rays into a single focus, and by the re¬
flexion from this large surface in 1747 he ac¬
tually set fire to wood at the distance of 70
yards. The experiment was next inverted, and
a burner placed in the focus, to have its rays
thrown parallel, and produce remote illumina¬
tion. But for this purpose a much smaller reflec¬
tor was sufficient, composed of bits of mirror
planted in a spherical cavity. The final improve¬
ment consisted in hammering thin plated copper
into a parabolic shape. These powerful reflec¬
tors, combined with Argand’s lamp, were about
thirty years since introduced from France into
our light-houses.
Buffon tried likewise to concentrate the power
of refracted x’ays. The ancient engravers had
employed spheres of glass or crystal to assist
vision; but the substitution of lenses, which at
the close of the thirteenth century served for
spectacles, was an important advance. This
figure greatly reduced the thickness of the dia¬
phanous mass, and therefore facilitated propor¬
tionally the passage of light. But the progress
of improvement seemed completed in the plan
proposed by the French Naturalist to obtain the
exterior surfaces of a lens by combining a num¬
ber of circular prismatic segments. From the
difficulty of the construction, however, this pro¬
ject was long retarded, and afterwards forgotten.
The knowledge of such attempts was not wanted
to direct the ingenuity of Fresnel1 into the right
path. He calculated the curvature of the suc¬
cessive concentric segments which would pro¬
duce a correct focus, and advanced the construc¬
tion to a regular system, on which Soleil, an ex¬
pert optician at Paris, has founded a manufac¬
ture. This compound lens has displaced the re¬
flectors from the French light-houses, and must
soon, from its very superior power of concentra¬
tion, become generally adopted.
The eighteenth century created a new branch
of optical science, destined to measure or com¬
pare the intensities of different lights, and there¬
fore termed Photometry. The first notions of
this curious subject were given by Marie, a
French Capuchin, in a small tract printed in
1700. Though this ingenious person erred
egregiously in the mathematical deductions, he
had probably the merit of setting to work the
superior talents and skill of his countryman
Bouguer, who published in 1729 an original
treatise on the gradation of light. He there sets
out from the obvious principle that light darting
in straight lines must become dilated or atte¬
nuated in the ratio of the square of the distance
from the radiant source. But the eye with a
little training can with tolerable accuracy dis¬
tinguish in a dark room when two surfaces pre¬
sented at once are equally illuminated, and con¬
sequently the relative powers of the lights may
be readily computed from the distances required
1 The insidious -advance of a consumption has arrested his career of discovery, and drawn that inventive and amiable
philosopher to a premature grave.
DISS. V. 5 C
754
PRELIMINARY DISSERTATIONS.
to produce such a congruous appearance. Bou-
guer compared the light of a candle with the
dazzling brilliancy of the sun and the soft ra¬
diance of the moon; and found that the inten¬
sity diminishes from the centre to the margin
of the solar disc, but that the gradation is in¬
verted in our satellite. He discovered also ex¬
perimentally the diminution of the sun’s rays in
traversing the atmosphere with different angles
of obliquity. The same able experimenter as¬
certained the loss of light, as occasioned under
different circumstances, by reflexion and refrac¬
tion. He then held the office of Royal Hydro-
grapher at Croisic in Lower Brittany; hut after
his return from the laborious and memorable
scientific expedition to Peru, he resumed his
early pursuits, and prepared an enlarged edition
of his optical work, which was edited by La-
caille in 1760, two years after his death. At
the same time came out the systematic treatise
which Lambert entitled Photometria, designed
as the sequel to a small tract which this ardent
and inquisitive philosopher had printed two
years before on the remarkable 'properties of the
route of light through the air. This production is
very complete in its mathematical structure; but
the experiments on which it rests are generally
not so well devised or so nicely performed as
those of Bouguer. The ingenious author seems
to confide too much in a sort of filtration and ad¬
justment of facts, as obtained by the aid of cal¬
culation. Lambert, in his preamble, admits the
imperfection of those observations, owing to the
infirmity and variable condition of the eye, and
regrets that he had no instrument like the ther¬
mometer to guide the sense of vision.1 This de¬
sideratum was happily supplied before the close
of the century; and the Photometer constructed
on the principle of the minute differences of
temperature is not only very delicate, hut ex¬
empt from the remotest chance of error. The
method of shadows proposed by Count Rumford
in 1796, may he reckoned an improvement on
Bouguer’s procedure, hut it is liable to the in¬
superable objection of depending altogether on
the patient attention of the observer and his un¬
certain sharpness of sight.
The present century opened with the most
auspicious prospects, and was soon distinguished
by one of those great and unexpected discoveries
which form an epoch in the progress of science.
Such may he regarded the fine detection of the
polarized rays of light by Malus, a French officer
of Engineers, and one of the most ardent dis¬
ciples of the Polytechnic School; which in so
short a period drew together and put into rapid
motion a far greater mass of mathematical and
physical talent than any of the older seminaries
in Europe. The double refracting property of
Iceland Spar, or the crystallized carbonate of
lime, noticed by Bartholinus and accurately in¬
vestigated by Huygens, had likewise engaged the
penetration of Newton, who concluded that the
ray which suffers the unusual or extraordinary
refraction must have its opposite sides affected
by some virtue like magnetism which gives them
a tendency to polarity.2 * 4 This curious and acute
remark appears to have lain neglected near a
hundred years among the crowd of ingenious
speculations started in the optical queries. Ma-
1 Optanduvi certe esset, ut excogitaretur Photometrum thermometro analogum, quod lumini exposituvi ejus intensitatem atque
claritatem indicaret. He subjoins, Enimvero ipseoculus ejus sistit exemplar, quippe pupillce apertura luminis sequitur magnitudinem
ac claritatem, et utrique sese accommodat. At magnopere dubitandum artem in hoc negotio naturam posse imitari. (Piiotometria,
sive de Mensura et Gradibus Lutninis, Colorum, et Umbrae, p. 7-)
4 The whole passage deserves transcribing. “ The unusual refraction of island crystal looks very much as if it were
performed by some kind of attractive virtue lodged in certain sides both of the rays and of the particles of the crystal. For
were it not for some kind of disposition, or virtue, lodged in some sides of the particles of the crystal, and not in their other
sides, and which inclines and bends the rays towards the coast of unusual refraction, the rays which fall perpendicularly on
the crystal would not be refracted towards that coast rather than towards any other coast, both at their incidence and at their
emergence, so as to emerge perpendicularly, by a contrary situation of the coast of unusual refraction, at the second surface;
the crystal acting upon the rays after they have passed through it and are emerging into the air, or, if you please, into a
vacuum. And since the crystal by this disposition or virtue does not act upon the rays, unless when one of their sides of
unusual refraction looks towards that coast, this argues a virtue or disposition in those sides of the rays, which answers to
and sympathizes with that virtue or disposition of the crystal, as the poles of two magnets answer to one another. And as mag¬
netism may be intended or remitted, and is found only in the magnet and in iron ; so this virtue, of refracting the perpen¬
dicular rays, is greater in island crystal, less in crystal of the rock, and is not yet found in other bodies. I do not say that
this virtue is magnetical; it seems to be of another kind: I only say, that whatever it be, it is difficult to conceive how
the rays oflight, unless they be bodies, can have a permanent virtue in two of their sides, which is not in their other sides;
and this without any regard to their position to the space, or the medium, through which they pass.” {Optics, book iii.
query 2'J.)
DISSERTATION FIFTH.
755
lus had early turned his attention to the more
difficult problems in optics, and after his return,
with a shattered constitution from an absence of
several years spent in foreign service, obtaining
more congenial employment at home, he re¬
sumed with enthusiasm his favourite studies,
and devoted to them every moment he could
spare. While intensely occupied with the in¬
vestigation of the phsenomena of double refrac¬
tion, a fortunate accident occurred, which dis¬
closed to him a new and splendid field of con¬
templation. In one of his frequent visits to
the Observatory, during his residence at Paris,
he chanced in the summer of 1809 to be struck
with the brilliant reflexion of the setting sun
from one of the windows of the Luxembourg
Palace, on looking at the appearance through
a prism of rock crystal which he slowly turned
round, and remarked with surprise that one
of the images changed regularly to brightness
from obscurity. Next morning he repeated this
6. DOCTRINE
Heat is the great principle of all internal mo¬
tion. Its various changes and gradations deter¬
mine the growth of plants and the expansion
of animated beings. The knowledge of the pro¬
duction of fire was the earliest of human disco¬
veries, and already distinguished our species in
its lowest condition from the brute tenants of
the forest. The application of that element has
most essentially contributed to the advancement
of the arts and the general progress of society.
It has contributed prodigiously to the increase of
population, by converting the crude produce of
the soil int$ nutritive and wholesome aliments.
Applied in a higher degree, it has aided industry
in fashioning the various utensils necessary for
the comforts of life ; but urged to the greatest in¬
tensity, it has enabled man to fuse the metallic
ores, and forge those efficient tools by which he
controls the powers of nature, and renders them
subservient to his convenience. What a vast in¬
terval in the range of progression from the rude
savage, that laboriously kindles two sticks by rub¬
bing them, to the experienced engineer, who com¬
bines all the deductions of philosophy in wield¬
ing and directing the resistless force of steam !
observation with the same results, and soon
found that light reflected at a certain angle
from the surface of glass acquires the same
character as the extraordinary ray in the double
refracting prism. Water showed a similar
disposition, but at a different angle of inci¬
dence. It was not difficult to trace the law
through the various reflecting surfaces; but
Malus extended his researches farther, and
pursued them with rapidity and success. But,
in the midst of this career, he was prema¬
turely carried away from his friends and the
philosophic world, by a lingering disease, on
the 23d of February 1812. The subject of
Polarity has been since carried forward by
several eminent experimenters both abroad
and at home, particularly by Arago, Biot,
and Fresnel, and by Brewster, Seebeck, and
Herschel; but it still wants the simplicity and
evidence which always mark the perfection of
science.
OF HEAT.
The Doctrine of Heat has, in the course of
the eighteenth century, been advanced to the
rank of a science. Its transfusion through the
mechanical arts has communicated a grand
movement to society, and wonderfully augment¬
ed our national wealth and resources. That a
subject so nearly concerned with the wants and
comforts of human life should have remained
during the lapse of ages in a state of mere in¬
fancy, might furnish matter for grave reflection.
The science is essentially experimental, while
the ingenuity of the ancients was expended in
framing loose and airy visions. Fire they held
to be the Fourth Element, which, by its extreme
levity, soared to the highest place in the Hea¬
vens, and spread its lambent ethereal essence
over the boundless regions of space. Being re¬
garded of pure divine origin, the sparks of the
celestial flame were believed to impart anima¬
tion to the beings of this nether world. But the
Heat which commonly pervades the terrestrial
bodies, and feeds our culinary fires, was consid¬
ered by the sages of antiquity as variable in its
constitution, and of a lower and perishable na¬
ture.
756
preliminary dissertations.
Heat was viewed by Aristotle as a peculiai
element, composed of minute particles in con¬
tinual agitation. Bacon, after a very prolix
and confused exemplification of bis formal me¬
thod of pursuing induction, arrived at a conclu¬
sion nearly similar, though less intelligible, that
Heat consists in a certain expansive motion.
But other philosophers, and especially the alche¬
mists, entertained juster notions of the subject.
They conceived Heat to be a material substance,
of extreme subtilty, diffused in various propor¬
tions internally through all bodies. Unfortu¬
nately those theorists were not very consistent
in their speculations. The different applications
of fire they considered as not merely varying in
degree, but quite distinct in kind. The heat of a
furnace and a stove, that of a sand and a water
bath, and that of putrefaction and fermentation,
seemed in their apprehension all separate species;
and animal heat was regarded by the Arabian
physicians as a finer essence, endued with invi¬
gorating and restoring virtue.
So long as such notions prevailed, it is evident
that no real advances could be made in the
knowledge of the properties of Heat. The first
thing required was to find a method of ascer¬
taining its intensity ; and for this invention we
are indebted to Sanctorio, Professor of Physic
in the University of Padua, the celebrated dis¬
coverer of Insensible Perspiration, who, near
the end of the sixteenth century, laboured with
ardour and success in improving Medical Science
by the application of Mechanics. Hero, of the
Alexandrian School, had anciently described a
curious machine, which, by the alternate ex¬
pansion and contraction of included air during
day and night, produced certain reciprocating
motions; the Paduan physician seized the prin¬
ciple, and constructed an instrument on a small
scale, chiefly adapted to measure the tempera¬
ture of the human body during fevers. It con¬
sisted of a pretty large ball of glass, terminating
in a long narrow stem, which was inverted and
plunged perpendicularly in water or coloured
liquid. For the sake of convenience, the ball
was sometimes flattened on the one side, and
the stem rendered more compact by serpentine
involutions. With this instrument Sanctorio
tried to measure the heat of the rays shot from
the sun, and even that of the lunar beams, which
were fancied then to have a gelid influence.
The Air Thermometer, as it is now called, was
about twenty years afterwards, though proba¬
bly without any communication, reproduced by
Drcbbel of Alcmaer in North Holland, who car¬
ried it, with other ingenious contrivances, into
England during the latter part of the reign of
James I. The instrument being observed to be
affected by the changesof weather, washencccall¬
ed a Weather Glass. In fact, it indicated only the
elasticity of the air, which depends on the blend¬
ed operation of two separate causes, the degree
of temperature, and the varying force of atmo¬
spheric pressure. But the latter influence was
yet unknown, nor till the great discovery of the
Barometer by Torricelli could it be distinctly
traced. The insufficiency of the Air Thermo¬
meter was then perceived, and another fluid sub¬
stituted, which sensibly expands by heat while se¬
cluded from the compression of the atmosphere.
The Florentine Academicians, about the year
1655, first constructed an instrument of that kind,
consisting as before of a glass ball, but filled
with spirit of wine, and having its stem of a
smaller bore, sealed hermetically, or melted at
the top by the flame of a blow-pipe. Italy had
thus the honour of inventing both those instru¬
ments, the Thermometer and Barometer, the
most important auxiliaries of modern science.
Three different forms of Thermometers, con¬
structed for the Academy del Cimento, were
copied and circulated over Europe. But the
great object now was to procure an exact cor¬
respondence, by fixing on some standard scale.
The Italians began the divisions at the cellar
heat, supposing this to be uniforrffc; and they
marked other points by plunging the ball in
certain chemical mixtures. Boyle proposed
the freezing of the oil of aniseed for the
lower point; and Halley recommended the
ebullition of alcohol as the limit of the scale.
The great advantage of deriving a point from
the congelation of water was not at first per¬
ceived. Many observers believed it to vary
under different circumstances, being deceived
by the fact that water will bear a greater
cold before it shoots into crystals, though the
temperature at which ice or snow begins to
DISSERTATION FIFTH.
757
melt is always the same. Guericke was the
first who started from the thawing point, in di¬
viding the scale of a large spirit of wine ther¬
mometer. To regulate the divisions, two different
ways occurred; either to assume a higher point,
or to distinguish into small portions the capa¬
city of the hall. The latter was the mode adopt¬
ed by Newton, who recreated his mind with
chemical experiments. Employing linseed oil,
which expands largely, and bears a great heat,
he subdivided the capacity of the glass into
10,000 equal parts; and beginning from the
point of thawing ice, he found the liquid to ex¬
pand 256 at the heat of the human body, 725 at
boiling water, and 1516 at melting tin ; but
preferring smaller numbers, he assumed 12 for
blood heat, and reduced the other numbers in
the same proportion to 34 and 71. This method
was quite philosophical, but of very difficult
execution. A correct and ingenious process for
determining the scale of heat was proposed in
1694 by Renaldini, a learned Italian mathema¬
tician. Taking the freezing and boiling of
water for the extremes, he found the interme¬
diate points from a mixture of ten parts, com¬
posed progressively of melting snow and water
just ceased from ebullition, the ingredients
being 1 and 9, 2 and 8, 3 and 7, &c. About
twenty years afterwards, Brook Taylor and
Hauksbee applied that ingenious mode to as¬
certain whether the expansions of certain fluids
are exactly proportional to the corresponding
accessions of heat.
It had been proposed by Roemer to fill ther¬
mometers with quicksilver, and Halley adopt¬
ed the suggestion. But instruments of this
kind being observed to disagree with the com¬
mon spirit of wine thermometers, the cause of
such discrepancy was now detected. Alcohol
swells with increasing progression on the appli¬
cation of heat; while mercury shows the valu¬
able property of expanding with an uniform
advance.
After the point’’of thawing snow had been
fixed, the degrees of the scale were generally de¬
rived from the decimal subdivision of the capa¬
city of the ball. But this absolute bulk is not the
true basis of the scale, since the expansion indi¬
cated by the thermometer must be the excess of
the dilatation of the liquid above that of the glass
which contains it. The mensuration of the ball
hence became troublesome and liable to much
uncertainty.
The first whoi succeeded in constructing ther¬
mometers with adequate skill was Fahrenheit.
This ingenious man had been a merchant at
Dantzic, and through misfortune failed in busi¬
ness ; but having a good taste for mechanics, he
removed into Holland, and settled as a philoso¬
phical instrument maker at Amsterdam. He
began with spirit of wine thermometers, which
he formed much smaller and neater than had
been attempted before. But he soon preferred
quicksilver, and having found it to expand
from freezing water to blood heat, about 60 parts
in 10,000, he assumed the number 64, and ob¬
tained the degrees by repeated bisections. In
this practice he was confirmed, on observing
what he considered as extreme cold, to descend
just through half that space, or 32 degrees. From
a mixture of water, ice, and sal ammoniac, the
scale commenced; 32 degrees were allotted for
the interval to ice-water, and 64 more for the
ascent to blood heat. But he afterwards enlarged
the range, and assumed another point from the
limit of boiling water, which he placed at the
212th degree in the mean state of the atmo¬
sphere, though liable to some variation from the
change of barometric pressure. Such was now
his confidence in the delicacy of the construction,
that he proposed the thermometer as an instru¬
ment for ascertaining the heights of mountains
from the depressed temperature of boiling water;
a very simple method, which has been lately re¬
vived by the reverend Mr Wollaston.
The thermometers manufactured by Fahren¬
heit being remarkably neat and convenient,
were, notwithstanding their arbitrary subdivision,
widely dispersed over Germany, and introduced
into Britain by the practitioners in physic, who at
that period usually resorted to Holland for medi¬
cal instruction. But most strangely in France
a very unwieldy and inaccurate instrument
maintained its ascendancy. The thermometer
of Reaumur had a ball near four inches in dia¬
meter, which was filled with spirit of wine dilut¬
ed with water. The scale began at the term of
congelation obtained by an artificial process, but
758
PRELIMINARY DISSERTATIONS.
the highest point was marked by plunging the
instrument into boiling water. But it is evident
that the liquid could never reach this degree of
heat, but would stop several degrees lower at
the limit of its own ebullition. Besides, so large
a mass receiving the impression very slowly,
would not indicate with any precision the tem¬
perature of the surrounding medium. Reckon¬
ing the ball to contain 1000 parts of the fluid,
the whole expansion was found to be 871, and
Reaumur therefore took the round number 80
for the extent of his scale. The same artifi¬
cial subdivision is still very generally retained,
though transferred to the mercurial thermometer,
which is exempt from the glaring defects and
errors of the original instrument.
Provided with Fahrenheit’s thermometer, the
philosophers of Holland and Germany made some
progress in the science of heat, while France ap¬
peared to rest satisfied with mere speculation.
But experimenters were too eager in hastening
towards general conclusions. While the theory
of gravitation possessed the charm of novelty,
it seemed natural to suppose that heat is distri¬
buted among bodies according to their density
or mass. This inference, however, is often very
remote from the fact. Boerhaave found that a
pound of mercury at 200°, so far from communi¬
cating to a pound of water at 82° half the excess
of heat, or 84°, as another pound of water at that
high temperature would have done, gave only an
addition of 4° ; so that twenty pounds of mercury
had scarcely as much heating influence as a
single pound of water. It would have required,
according to his experiment, even a greater bulk
of mercury by one-half more, to produce the
samy calorific effect as water. Had he perform¬
ed the process with due precaution, he might
have observed that hot water exerts as much in¬
fluence as mercury of 32 times its weight or 2^
times its volume. But this celebrated chemist,
satisfied with gross results, and mistrusting per¬
haps his own experiments, hastened to the con¬
clusion that heat is distributed among bodies in
proportion to their bulks., or maintains an equal dif¬
fusion through space. This principle was likewise
adopted by Musschenbroeck, and the simplicity
of the proposition seems to have procured it a
very general reception.
Wolfius, who about this time was spatiating
over the vast field of physical and moral science,
and forming a new philosophical sect in Germany,
taught that bodies had two sorts of interstices,
the one filled with air and the other charged with
fire. He attempted to explain why iron acquires
heat sooner than wood, and why the solution in
nitre occasions cold; but neglecting to follow
experiments, he produced only vague andshallow
speculation. Equally visionary, but enlivened
by French vivacity, was Mairau’s Dissertation
on Ice, published in 1740.
The most judicious writer that had yet ap¬
peared on the subject of heat was Dr Martine1
of St Andrews, who studied medicine on the
Continent, and, like the accomplished physicians
of that period, cultivated learning and general
science. His acute Essays, published in the
years 1739 and 1740, not only corrected the
different thermometric scales, but enriched phi¬
losophy by several well-devised and original ex¬
periments. Unfortunately the career of this pro¬
mising genius was very short. Having in the pur¬
suit of his profession accompanied Admiral Ver¬
non in the fatal expedition against Carthagena, he
perished by a malignant fever. Martine did not
consider with sufficient attention the unequal
distribution of heat among bodies, but he care¬
fully investigated the variable rates of heating
and cooling of different substances. He noticed
especially the facility with which mercury, in
comparison of water, receives or parts with its
heat. He conceived the process of cooling to be
commonly retarded by a sort of covering or
atmosphere of warm air closely encompassing
the body; and he endeavoured to distinguish two
sources of the dispersion of heat. Had such in¬
vestigations been steadily prosecuted, they must
have led to interesting result^.
1 He was the son of George Martine, a small Fife proprietor, who having officiated as chamberlain to Archbishop Sharp,
wrote a credulous and bigoted account of the See of St Andrews. The youth displayed the principles of the defunct
Episcopacy, by heading a riot of some students at the College of St Andrews, on the breaking out of the feeble rebellion
in 1715.
DISSERTATION FIFTH.
759
About this time, the practice of making obser¬
vations with the thermometer had become pretty
general in England, in consequence of the dif¬
fusion of the very neat and accurate instruments
manufactured by Fahrenheit and Prins, at Am¬
sterdam, which were likewise imitated in London
by Wilson, who afterwards established a flou¬
rishing type-foundry at Glasgow, and held the
professorship of Practical Astronomy. These
thermometers were filled with quicksilver, and
only four or five inches long, the stem clasped by
a folded paper scale, engraved with successively
bisected divisions, and the whole inclosed in a
thin glass case. But the most philosophical con¬
struction of the thermometer was now proposed
by tbe learned Celsius, who filled the chair of
Astronomy in the University of Upsal, and had
borne an active share in the operation of deter¬
mining a degree of latitude on the verge of the
Arctic Circle. He started from the point of
congelation, and reckoned just a hundred di¬
visions upwards to that of ebullition. This
simple scale, commonly used in Sweden and
Denmark, is the same as that which was after¬
wards adopted by the French under the name
of centigrade^ in their complete and elegant
system of decimal weights and measures. It is
singular that Deluc, in rectifying Reaumur’s
thermometer, should have retained such an arti¬
ficial subdivision as that by fourscore. But this
philosopher had the merit of ascertaining that
mercury dilates almost uniformly with equal
additions of heat, while the expansion of the
spirit of wine is variable, and ascends with an
accelerating progression. A thermometer form¬
ed of alcohol, whether diluted or not, is hence
exceedingly inaccurate, unless it be regulated by
the comparison with a mercurial one.
The practice of using thermometers filled with
quicksilver led to the curious discovery of the con¬
gelation of that dense liquid. Professor Gmelin,
who had been sent with a party of naturalists
to explore the remote regions of the Russian
empire, observed in Siberia, on the 16th of
January 1735, the mercury to sink in the ther¬
mometric tube to a point which corresponds to
the 120th degree below the zero of Fahrenheit’s
scale, while it changed into a solid mass. But
the artificial freezing of mercury was first per¬
formed by Braun, Professor of Philosophy at
Petersburg, in the month of December 1759,
when the natural cold seemed to be 34° under
tbe beginning of the scale. Having plunged the
bulb of a thermometer into a mixture of pounded
ice and sal ammoniac, the quicksilver appeared to
sink progresively to 350°, and then to consolidate.
But such enormous cold exceeded the bounds
of credibility, and iEpinus soon discovered the
source of this illusion. Employing tubes of a
wider bore, he observed the quicksilver, drawing
afterit a concave surface, to retreat as it congealed,
and sink into the rest of the liquid mass. The
semi-metal must therefore have suffered a large
contraction in the act of freezing, and become
much denser. Yet twenty years elapsed before
the point of mercurial congelation was correctly
ascertained. On the 16th of January 1780, Von
Elterlein of Vytegra, a town of Northern Rus¬
sia, in the latitude of 61°, found that some pure
quicksilver exposed in a porcelain tea-cup during
the night had become solid, but began to melt
again when the thermometer rose to 40 degrees
below the zero of Fahrenheit’s scale. This limit
was more decisively fixed, at the suggestion of
Dr Black, by Hutchins, then governor of Hud¬
son’s Bay, who repeatedly froze mercury during
the winter of 1781-2, by tbe application of artifi¬
cial cold. In rigorous climates, or for measuring
very depressed temperatures, it hence becomes
necessary to employ thermometers filled with
alcohol, which has never been made to freeze.
The cold occasioned by the evaporation of
water and other liquids in the more genial
regions had been known and turned to domestic
use from the earliest ages. In the northern
countries, that property, being less apparent,
was commonly disregarded; but the thermo¬
meter now detected changes which might elude
ordinary observation. It was soon remarked
that, after dipping the bulb in water or alcohol,
the quicksilver constantly sunk in the stem.
About the year 1750, Dr Cullen, then Lecturer
in Chemistry at Glasgow, in repeating some
experiments with a pupil, remarked that a ther¬
mometer with a wetted bulb showed a much
greater depression of temperature under the ex¬
hausted receiver of an air-pump. But he did
not pursue the observation farther, or attempt
PRELIMINARY DISSERTATIONS.
760
to investigate the theory of evaporation. This
interesting subject remained long afterwards in¬
volved in deep obscurity.
The temperature of water exposed to heat ap¬
pears to rest stationary at the two distinct limits
of freezing and boiling, which serve to mark the
points of the thermometric scale. Though the
fact had been long well known, it was first ex¬
amined with attention in 1760 and the three fol¬
lowing years by the celebrated Dr Black, who had
already distinguished himself by unfolding the
nature and properties of fixed air. He rightly in¬
ferred that a certain additional share of heat must
at each station unite with what is already lodged
in the substance of the ice or the water ; but not
aware that he was really framing an hypothesis,
he termed the former Zateni and the latter
heat. Strictly speaking, however, all heat is
latent or concealed from the senses, and never
exhibited in a detached form. The thermometer
indicates merely the heat contained in its own
bulb, and not necessarily that of the body with
which this communicates. “ But heat is evident¬
ly not passive ; it is an expansive fluid, which di¬
lates in consequence of the repulsion subsisting
among its own particles; and it would spread in¬
definitely through space, if it were not fixed or
retained by the counterbalancing attraction of
the substances which absorb it. Were each cor¬
puscle to exert the same action, this universal
fluid would be disseminated among bodies, ex¬
actly in proportion to their respective quantities
of matter. The mutual adhesion depends, how¬
ever, on the density of the substance, modified
by its degree of inherent disposition to combine.
A sort of affinity or specific attraction for heat
is thus produced, evidently proceeding from the
peculiar nature of each body. To trace its im¬
mediate origin is not more possible perhaps
than to discover the source of other physical
properties. Yet there appears some tendency
towards a general principle : the particles of
heat, like those of all expansive fluids, have their
repulsion diminished in proportion to their mu¬
tual distance; while the molecules of the con¬
taining substance suffer the corresponding de¬
crease of attraction after a slower ratio than the
spaces of internal separation. Heat has there¬
fore a narrower range of density than the bodies
with which it combines. It holds a sort of
middle station, and is distributed according to
the quantity of matter, joined to the considera¬
tion of the space which this occupies; that is,
it obeys some compounded relation of the weight
and the bulk. Hence the denser bodies receive
a proportionally smaller share of heat. Thus,
a pound of metal contains less heat than one of
stone ; this, less than an equal weight of liquid;
and this last, still less than a pound of any spe¬
cies of gas.”
“ When two bodies are united chemically, the
compound has an attractive force generally dif¬
ferent from that of the mean result. Hence a
corresponding portion of heat is, during the act
of coalescence, either absorbed or evolved. Thus,
water, on being joined to sulphuric acid, occa¬
sions an extrication of heat, because the diluted
acid exerts less power of adhesion than did its
ingredients. And, for an opposite reason, the
muriate of ammonia, in dissolving, is attended
by an absorption of heat, or an apparent pro¬
duction of cold.”
“ Every substance capable of assuming differ¬
ent states of constitution betrays likewise ana¬
logous variations of attractive force. When a
solid body melts into a fluid, and thence passes
into vapour, each transit is marked by an aug¬
mentation of that force, and is therefore accom¬
panied with a corresponding absorption of heat;
during which process, the temperature must
evidently remain stationary. Thus, a lump of
ice transported intensely cold into a close apart¬
ment, will grow warmer by regular gradations,
till it begins to thaw, and then the farther accu¬
mulation of heat will appear to be suspended;
and if the water so formed be poured into a
covered pot, and set over a steady fire, the tem¬
perature will again rise uniformly, till it reaches
the limit of boiling, when the act of conversion
to steam will henceforth absorb the whole affluent
heat; yet the temperature will mount still higher
if the escape of the vapour be prevented, but
which soon acquires such prodigious elasticity as
to burst whatever obstacle can be opposed to it.”1
1 Experimental Inquiry into the Nature and Propagation of Heat, pp. 529—531.
DISSERTATION FIFTH.
761
The first that made any advance towards such
views of the distribution of heat was Irvine,
who had been assistant to Black at Glasgow.
Unfortunately he seems to have introduced the
term Capacity, which involves a crude notion, as
if heat were merely passive, filling up the interior
pores or internal vacuities of bodies. But, a
few years afterwards, Wilcke of Stockholm,
directed, he says, by the views of his col¬
league Klingenstierna, a mathematician and
philosopher of the first order, examined the sub¬
ject philosophically, and performed several accu¬
rate experiments. Thus, he found that water at
98° of Celsius, poured upon an equal weight of
snow, had its temperature reduced to 13°, and
that three parts of water at 40°, joined to one
of snow, produced the common temperature of
12°. These trials gave both the same result, or
73° of Celsius, corresponding to \2Q'Qa on Fah¬
renheit’s scale, for the increase of heat required
to convert snow into water.1 A similar conclu¬
sion was obtained by filling equal tin vessels
with equal parts of snow and snow-water, and
placing these within a larger one full of boiling
water, and set over a fire; the moment the chill
water rose to 72°, the snow had all melted.
In 1780 Lavoisier, assisted by Laplace, and
employing his Calorimeter, ascertained the heat
evolved from different bodies during their va¬
rious changes, from the several quantities of ice
which it melted. This seemed to be a very simple
and correct mode of investigation; yet was it
liable to considerable inaccuracy, from the large
portion of water which still remained adhering
to the mass of pounded ice. But the French
chemists rather confused the subject, by mixing
up incongruous principles. Embracing the the¬
ory of Capacity, they likewise tacitly adopted
the hypothesis of sensible and latent heat, only
changing these terms by a sort of appropriation
into free and absolute, while the poverty of their
language suggested for that fluid such an im¬
perfect etymon as Caloric.
The best series of experiments on the dis¬
tribution of heat among different bodies was
performed before the year 1784 by Professor
Gadolin of Abo, who, rejecting the notion of
Capacity, introduced the unexceptionable ex¬
pression, Specific Heat. One of the most beau¬
tiful consequences derived from this theory, was
the determination of the absolute zero or lowest
point in the scale of Heat. Two different ways
of solving the problem led to nearly the same
results: 1. From the measure of Heat absorbed
in the melting of ice, and 2. From the quantity
evolved in the mixture of certain liquids. Thus,
it being found that the heat contained in water
is to that of ice as 10 to 9, and that 135 degrees
are required for the equilibrium of the liquid
constitution, it follows that the water just formed
must actually contain 1350 degrees of heat, or
that the real scale would descend to the enor¬
mous depth of 1318° below the beginning of
Fahrenheit’s divisions. Again, the concentrated
sulphuric acid holding only six tenth parts of
the heat of water, the arithmetical mean of a
mixture of one part of it by weight with three
of water would evidently be nine tenths; but
suppose the specific heat of that compound were
only eight tenths, while the thermometer rose
on the affusion 169°, or from 32° to 201°, the
whole extension below the point of congelation
would be 8° x 169°, or 1352°. This experiment
is susceptible of greater accuracy than the for¬
mer, and deserves to be repeated in different
proportions. Considerable discrepancies have
hitherto affected such observations, arising pro¬
bably from the want of sufficient precaution in
the manner of conducting them.
Dr Crawford followed nearly the same train,
and was enabled, by employing finer instruments,
to obtain a greater degree of precision. He took,
on the whole, a philosophical view of the sub¬
ject, but sacrificed his better judgment to popu¬
lar opinion, by retaining also the hypothesis of
Latent Heat, tc the ideas associated with which
have spread a cloud of mystery and paradox
most unfavourable to the progress of real science.’*
It is to be regretted that a similar confusion of
ideas should still pervade the writings of so
1 In the first experiment the hot water lost 98° — 13°, or 85°, rvhile the snow water gained only 13°, or had absorbed
72°: in the second experiment the hot water had transferred 3 (40 — 12) or 84°, and consequently 84° — 12°, or 72°, was
spent in liquefying the snow. If every precaution were used, the measure of heat absorbed would amount to 75° of Celsius,
or 135° by Fahrenheit’s scale.
D1SS. V. 5 D
762
PRELIMINARY DISSERTATIONS.
many of the chemical philosophers. Crawford
had expected much accuracy from thermometers
with large bulbs and minute subdivisions; but
these advantages were more than overbalanced
by the want of delicacy to transient impressions.
On a revision of the experiments from which he
sought to ground his theory of animal heat, he
had occasion to change the numerical results.
About this time shone forth the brilliant and
original genius of Scheele, who not only ex¬
panded the boundaries of chemistry by his va¬
rious inventions, but enriched other departments
of physical science. In particular, he bestowed
a keen glance on the subject of the emission of
Heat.
That Heat, and even the opposite influence, im¬
pression of Cold, admits of Reflexion, like light, is
a property longknown, and had been distinctly an¬
nounced by Baptista Porta, in the sixth edition of
his Natural Magic, printed about the year 1590.
This remarkable experiment was more particu¬
larly described in 1632 by Cavalleri in his tract
on the Burning Speculum: it was repeated and
varied in 1658 by the members of the Academy
del Cimento, who received the impression on the
bulb of an air thermometer. The concentration
of cold in the focus of a metallic reflector was
again tried, during the severe winter of 1740,
by the academicians of Petersburg, though with
rather doubtful results, owing to their ignorance
of the true circumstances on which the success
depends. But, after an apparent oblivion of near
forty years, the experiment was revived with
striking effect at Geneva, and continues to hold
a conspicuous place in every course of physical
lectures.
Mariotte, as far back as the year 1682, had
made a capital remark, which some late disco¬
veries have revived and explained. That able
experimenter, in concentrating the heat of a fire
by help of a burning mirror,1 found the effect
to cease when a piece of glass was interposed
behind the focus. A similar experiment was
about the same time made by Hooke, though
not published till very long afterwards. This
ingenious philosopher showed that a glass mir¬
ror which reflects light will not repel heat.
But these interesting facts lay buried for a cen¬
tury amidst a multitude of scattered observa¬
tions, and seem to have first attracted the no¬
tice of Saussure and Pictet, both of whom, and
especially the latter, carried the investigation
to some extent. They still wanted the connect¬
ing principle, which should embody and re¬
animate the mass.
Scheele pursued a similar path, but was little
versant in the history of science, and had none
of the advantages of an improved apparatus.
Endowed with original and inventive powers,
he followed the current of his own conceptions,
and consulted always the book of Nature. An
examination of the circumstances disclosed in
the management of stoves and chemical furnaces,
induced him to consider Heat or Fire as existing
under two distinct modifications; one which rises
and spreads by a successive transfer among the
ambient substances, and the other which streams
immediately from its source in rectilineal direc¬
tions. The latter he designated by the phrase Ra¬
diant Heat, which has since become a favourite
appellation. If this expression indicated merely
the tendency of Heat, under certain circum¬
stances, to disperse in straight lines, it would be
quite unexceptionable. But in technical lan¬
guage, the Radiation of Caloric associates an ob¬
scure idea of a subtile fluid invested with vague
or uncertain properties.
The common thermometer comprises, between
freezing and boiling mercury, the space of scarce¬
ly 700 degrees; which is evidently but a small
portion of the vast range of heat. It was most
desirable, therefore, to have an instrument of
greater extent, adapted especially to the ascend¬
ing scale. The Pyrometer, composed of metallic
1 This must have been a metallic reflector: an ordinary mirror, or one of silvered glass, will scarcely collect any heat at all.
Indeed the art of applying a metallic plate to the surface of glass is a modern invention. The earliest method was the
Dutch, which consisted in pouring melted lead intensely hot over a sheet of glass softened nearly to fusion. But the
adhesion was afterwards more easily obtained in the ordinary way, by applying tinfoil to the glass, and dextrously flooding
it with mercury, to form an amalgam. It is from this shining metallic coating that light is chiefly reflected, having pene¬
trated and again escaped through the substance of the glass. But with regard to Heat, a very small reverberation takes
place at the anterior surface of the glass, and the effect is exactly the same if the silvering be rubbed off. It would prevent
much confusion were chemical writers to appropriate the term speculum to metallic reflectors.
DISSERTATION FIFTH.
763
bars, answered, though very imperfectly, that pur¬
pose. But the elegant contrivance of Wedgwood,
the celebrated improver of English pottery, pro¬
mised the greatest advantages, both to science and
the chemical arts. It consisted merely of a small
cylindrical piece of finely prepared clay, which
bears the most intense heat, and yet regularly
contracts in the fire. Assuming that the intensity
of heat must cause a proportional contraction, he
measured this by sliding the thermometric piece
within a tapered groove, its width at the one end
being to that of the other as 5 to 3, and its whole
length divided into 240 equal parts. By com¬
paring the dilatation of silver, it was found that
each of these divisions answers to 130 degrees of
Fahrenheit’s scale. Hence the melting points of
silver, gold, and cast-iron, and those of the fusion
of flint-glass and of Chinese porcelain, being re¬
spectively 28, 32, 130, 114, and 156, by Wedg¬
wood, would correspond to the enormous num¬
bers 4717°, 5237°, 17977°, 15897°, and 21257°.
These results, however, appear far to transcend
the truth. The principle of the instrument is
totally different from that of the thermometer.
It does not mark the transient impression of
heat, but the change or permanent effect pro¬
duced on the bit of clay by baking, or the ex¬
posing it during a certain time to the action of
the furnace. Hence the very ingenious method
of discovering the degrees of heat which the
Chinese and the ancient Etruscans employed
in their potteries, by observing the moment
when a specimen of their ware subjected to an
increasing fire began to contract anew. That
contraction is undoubtedly caused by the ex¬
pulsion of a part of the water held so obstinate¬
ly by the clay, the repulsive force excited by
the accession of heat controlling the adhesion
of the moisture. It may be inferred that the clay
attracts the remains of latent humidity with a
force always increasing; but the repulsion in¬
fused by the conversion of the expelled particles
into steam ascends nearly in a geometrical pro¬
gression with equal accessions of heat. A nearer
approximation to the scale of temperature might
probably be derived from the logarithms of the
very large numbers stated above.
It remains however still an important deside¬
ratum to construct a thermometer that shall
accurately measure the higher degrees of heat.
The fusible metal, composed of lead, tin, and
bismuth, has been suggested as an expansible
substance, which may be heated to near the fusion
of copper; but, in congealing again, it unfortu¬
nately swells suddenly, and would burst its glass
ball. A combination of metallic bars has like¬
wise been proposed, though no plan for effecting
this has yet been devised, sufficiently simple and
reducible to practice.
Metallic thermometers have indeed been con¬
structed, which indicate with great delicacy
the ordinary temperature, and all the sudden
changes of heat. These consist generally of thin
slips of steel and brass, united together, and
formed into circles or spirals. The most elegant
instruments of this sort were executed at Paris,
by the late ingenious artist Breguet.
It was an object of much greater consequence
to construct a register-thermometer, which should
mark the greatest heat and cold during the ab¬
sence of the observer. This had been attempted
by dift'erent experimenters in the course of the
eighteenth century, but was first carried to
any tolerable perfection about the year 1780, by
Mr Six of Canterbury. These registers consisted
of spirit of wine thermometers, with compound
reverted stems, partially filled with quicksilver,
which carried small bits of steel to indicate
the limits of ascent. With such instruments
the inventor made some curious observations on
local heat, or on the differences of temperature
at moderate altitudes during the alternations of
day and night. He particularly remarked the
influence of a clear sky in chilling the ground.
The simplest and most commodious register-
thermometers, however, were a few years after¬
wards contrived by Dr Rutherford, an ingenious
physician, who resided on his property in the
neighbourhood of Kinross. They turn on a
pivot, the stems being placed nearly horizontal,
and only reclined occasionally for adjustment
after the heat of the day. The minimum ther¬
mometer is filled with alcohol, and the maxi¬
mum one with mercury, the tubes of both being
rather wide, with bits of enamel swelled at
each end, which are drawn down the slant¬
ing tube by the retreat of the alcohol, or pushed
upwards by the expansion of the mercury. Ruth¬
erford’s thermometer was first happily applied
by his neighbour Dr Coventry, the well-known
764
PRELIMINARY DISSERTATIONS.
Professor of Agriculture in the University of
Edinburgh, in ascertaining the progress of heat
into the ground, and its effects on the germina¬
tion of the seeds of the cerealia. Some curious
facts have thus been detected regarding the in¬
fluence of an herbaceous covering to retard the
penetration of frost.
The thermometer soon afterwards received
a most important modification, which renders
that instrument extremely sensible to the alter¬
ations of local heat. This improvement consist¬
ed in adapting the instrument to measure, not
the actual temperature of any spot, hut its occa¬
sional change or variation. The extent of the
scale being limited, the dimensions of the de¬
grees could he proportionally enlarged.
The construction of the Differential Thermo¬
meter was early suggested by a close analysis of
the phsenomena of evaporation. It is well known
that a wet sponge suspended in the air loses gra¬
dually its water, and during this dissipation it
continues colder than the encircling medium.
The depressed temperature was commonly attri¬
buted to a process of rapid evaporation, which
seemed to result from the combined action of vari¬
ous causes,—the heat of the air, its state of dry¬
ness or rarefaction, hut especially the swiftness
of its circulation. Halley had, near the close of
the seventeenth century, advanced the rational
hypothesis, that moisture is exhaled from the
surface of water by a sort of chemical solution
in the atmosphere. The same opinion was
about the middle of the following century pro¬
posed and expounded by Le Roy of Montpellier;
but though supported by concurring analogies,
it might appear perhaps too simple for the ge¬
neral taste. The fanciful notion, first started
by Derham, that evaporation is occasioned by
very minute vesicles or hollow spherules of
water, charged with highly attenuated air, which
rise and float in the atmosphere, proved more
acceptable to a wondering public. The vesicular
theory afterwards obtained a wide currency from
the philosophical reputation of Saussure, who
considered it as countenanced by some dubious
optical appearances. But the mere subdivision
of fluid matter could produce no change of tem¬
perature, and the clearest facts are opposed to
the notion of a passive dispersion of aqueous
corpuscles.
An absorption of heat always accompanies
the passage of a fluid from the liquid to the
gaseous form, which seems to require the same
surplus, in whatever way the conversion has
been produced. If a body of air he confined
over a surface of water, it will soon become
charged with moisture, and then there is no
more evaporation. But if the damp air he suf¬
fered to escape and disperse itself, the process
will be perpetually renewed. The correspond¬
ing abstraction or transfer of heat must conse¬
quently proceed without intermission. Although
the dissipation of moisture and of heat from a
humid surface exposed to a current of air con¬
tinues incessant, the coldness thence resulting
is not, however, likewise progressive. A wet
sponge or a porous vessel full of water will,
when placed in the same situation, gradually
arrive at a certain depression of temperature;
nor will this limit alter without a change of cir¬
cumstances. It follows, therefore, that the ex¬
haling surface, after it has become colder than
the ambient medium, must begin to receive as
well as to discharge heat. Every thin shell of
air which successively comes to touch the hu¬
mid surface must he cooled doAvn to this stand¬
ard, and thus deliver its excess of heat, while it
absorbs another portion spent in vapourizing the
moisture it dissolves. As the process of evapo¬
ration goes on, the heat communicated at each
repeated contact of the fugacious medium must
soon come to he precisely equal to what is again
abstracted from the exhaling liquid in the act of
saturation. When this equality of interchange
is attained, the resulting temperature must have
reached its lowest point of depression, where it
will continue stationary. But the heat deposit¬
ed by each successive shell of air must evidently
he proportional to that depression, which will
hence indicate the portion of humidity that
passes into the gaseous state of solution; or the
difference of temperature induced will furnish
an accurate measure of the dryness or distance
from saturation of the circulating air* To ob¬
tain, therefore, a perfect Hygrometer, it was
only required to construct a Thermometer that
should mark distinctly small differences of heat.
In the first application of this principle, made
as early as the year 1791, the water was eva¬
porated from a thin porous earthen cup, like
DISSERTATION FIFTH.
765
a truncated egg-shell; and the thermometer had
rather a large bulb, with a very narrow bore,
and bearing a scale of only a few degrees sub¬
divided into tenth parts. The tube was not
sealed, but had a wider cup of glass cemented a
little below the top, containing some mercury,
which united with that of the stem when the
instrument was inverted, and separated the mo¬
ment it was dipped into the evaporating cup,
leaving the mercurial thread to contract down¬
wards from the end. This arrangement was
found, with due care and attention, to answer
satisfactorily. It was more than three years
afterwards, when the severity of the season
suggested the idea of making the ball of the
thermometer itself the evaporating surface, by
covering it with a crust of ice.
The next advance was at all times to invest
the ball with a thick coat of tissue paper or soft
lint, that should hold a sufficient charge of
water. To find the depression of temperature
which marks the dryness of the air, nothing
was wanted but to compare it with another
thermometer having a naked bulb. This pur¬
pose appeared to be most easily effected, by
joining the stems of two air-thermometers; and
thus was fortunately produced the Differ¬
ential Thermometer, which under a variety
of forms is capable of so many curious and im¬
portant applications. Its primary object was
to serve for an Hygrometer, but the instrument
was soon found, when placed out of doors, to
be sensibly deranged by the diffuse light of the
sky. This circumstance led to its modification
as a Photometer, the covering being removed
from one of the balls, and the other ball blown
of black enamel. The addition of a pellucid
glass case now became necessary, to screen the
action of light from the consuming and irregu¬
lar influence of wind. The luminous rays pass
without interruption through the clear ball, but
are by the dark ball absorbed and converted into
heat, which continues to accumulate and to raise
the temperature, till the corresponding augment¬
ed dispersion of heat by the ambient air comes
at length to equal the continued accessions from
the afflux of light.
In arranging the instrument as an Hygrome¬
ter, it was hence requisite to neutralize the pho-
tometrical influence, by covering the evaporat¬
ing ball with coloured silk, and blowing glass
or enamel of the same shade for the naked ball.
A free exposure to the atmosphere is in this
case essential. The sweep of the wind may
accelerate the equilibrium, but cannot derange
its limit; for the same portion of air which ab¬
stracts vapour and the constituent heat, likewise
deposits its excess of temperature on the chilled
surface of the wet ball. The interposition of a
screen will not in the smallest degree affect the
indication of this Hygrometer,—a result at com¬
plete variance with the notions generally re¬
ceived. To regulate the scale of the instrument,
the tenth part of the centesimal subdivision was
adopted, or the distance from freezing to boil¬
ing was distinguished into a thousand degrees.
By successive improvements in its construc¬
tion, the Differential Thermometer was render¬
ed simple, precise, and elegant. But the instru¬
ment still betrayed imperfection, the limit of
equilibrium or the zero of the scale visibly sinking
in the course of several months. This was owing
to the diminished elasticity of air in immediate
contact with the liquid lodged below one of the
balls, which continued to absorb oxygen, and
deposit its colouring matter. But early in
1800 every source of error was removed, by
adopting, as the movable fluid, concentrated sul¬
phuric acid tinged with carmine, which remains
unaltered for any length of time, though ex¬
posed to the full glare of the sun.
The precision of the Differential Thermome¬
ter now fitted it for a variety of nice inquiries.
One of the most important was to ascertain the
alteration of the charge of heat in air, cor¬
responding to a change of the elasticity or vo¬
lume of this fluid. When the variation was
small, the allowance of two centesimal degrees
for each hundredth part of the difference of
density seemed to be a very near approxima¬
tion. Thus, if a mass of air be condensed one
fiftieth part, it will have its temperature raised
one degree, or give out one degree of heat; on
the contrary, a like expansion of air occasions
an equal absorption of that element, or the ap¬
pearance of cold. But when the difference of
elasticity is considerable, some modification be¬
comes requisite; and a very simple formula was
found to connect the experimental results. Let
this elasticity change from 1 to e, then the heat
preliminary dissertations.
766
evolved or absorbed is expressed in centesimal
degrees by 25“ (e — i) or O’ A SI'
milar mode of investigation determined the re¬
lative shares of heat contained in the artificial
gases and in common air.
This principle elucidates the decrease ol tem¬
perature in the higher strata of the atmosphere,
while the formula exhibits the scale ol grada¬
tion. Hence, knowing the mean temperature
of the ground at any part of the globe, it is easy
to compute the elasticity and corresponding
elevation which would reduce that to the zero,
and mark the limit of perpetual congelation. A
curve is thus traced, bending at first with a
gentle declivity on either side from the equator,
and then descending more rapidly and turning
with a contrary flexure, grazing along the sur¬
face at the pole. The application of the instru¬
ment led more immediately to the solution of
another important physical problem,—to deter¬
mine the proportion of humidity or of volatiliz¬
ed water which air is capable of holding in so¬
lution at different temperatures. A very simple
law was derived,—that the quantity of moistuie
dissolved constantly doubles at every 15 degrees
in the rise of temperature. Thus, air at the
freezing point may contain the two hundredth
part of its weight of moisture, but at 15° it will
hold the 100th, at 30° the 50th, at 45° the 25th
part; so that, if it were safe to push the pro¬
gression to its extremity, the air could unite
with rather more than half its weight of steam
at the limit of ordinary ebullition.
Similar conclusions were derived from the
waste by exhalation at different temperatures.
A large hollow ball of thin metal, covered with a
close coat of linen, and filled with boiling water,
being suspended from the end of a fine beam, and
10 grains of water at successive intervals repeat¬
edly sprinkled over the surface, the times of
dissipation were carefully noted, and the corre¬
sponding solvent powers of air hence inferred.
The Hygrometer likewise determined the re¬
lative portions of Heat contained in water and
air. It is evident, from the theory before ex¬
plained, that were the heat diffused according
to the densities of these fluids, each millesi¬
mal degree of moisture would equal the 6000th
part of the air which held it. But adopting
the capacity or measure assigned to air by
Dr Crawford (then esteemed the most accurate),
each hygrometric degree would correspond to
the 3460th part of the weight of the solvent.
Both of these proportions were found, however,
to differ widely from the truth. A wet card
being tied to the instrument, it was let down
into the centre of a large glass globe with a
narrow neck, containing 4000 cubic inches of air,
and suspended through a hole in the glass cover
from a fine balance; the progress of humifaction
and the concomitant loss of weight were at short
intervals of time nicely observed. From this
comparison it resulted, that the moisture suffi¬
cient to mark an hygrometric degree is only the
20,000th part of the air with which it unites.
Hence the atmospheric fluid, instead of being
charged with nearly twice as much heat as water,
as had been generally presumed, holds only three-
tenths of that quantity. The proportion after¬
wards given, in some elaborate experiments of
Petit and Dulong, was rather smaller, or 26
parts in 100; but the former result is simpler,
and probably more exact.
The principles thus established serve at once
to confirm and illustrate the ingenious Theory
of Rain, which the keen sagacity of Dr James
Hutton had elicited from observation about the
year 1786. The commixing of two bodies of
damp air that have different temperatures, must
always occasion a precipitation of moisture more
or less copious; for, since the solvent power
augments in a geometrical progression, the loss
of it which the warmer air suffers will con¬
stantly exceed what is gained by the heating of
the colder portion of the damp mass.
A curious conclusion followed from those
data: Supposing the vast canopy of air, by some
sudden change of internal constitution, at once
to discharge its whole watery store, this precipi¬
tate would form a sheet of scarcely five inches
thick over the surface of the globe. During the
course of a year, our atmosphere must there¬
fore deposit five or even ten times all the mois¬
ture it held in solution. To explain the actual
phenomena, it is hence requisite that this rest¬
less medium should change unceasingly from
a state of dryness to humidity. Such alter¬
nations are effected by the system of winds,
which sweep variously over the land and the
DISSERTATION FIFTH.
767
ocean. But to complete Dr Hutton’s Theory of
Rain, it becomes necessary to have recourse to
the operation of opposite humid currents of dif¬
ferent temperatures, which bring1 their grazing1
sui faces into rapid intermixture over a given
spot, where the aqueous precipitate is copiously
discharged.
A fui ther application of the Hygrometer de¬
tected the influence of rarefaction in augmenting
the dryness of air. The change is rendered very
perceptible, by introducing that instrument in its
quiescent state under the receiver of a pneuma¬
tic machine. On working the pump, the hygro-
metric action which had ceased is instantly re¬
newed, and urged constantly forward in propor¬
tion as the process of exhaustion advances. The
dryness thus induced amounts to 50 degrees,
every time the rarefaction is doubled. If air
had the same temperature at all elevations, it
would exhibit a regular gradation of dryness.
But at each ascent of 2800 feet, though the air
is constitutionally 7 degrees drier, it likewise
becomes 5 degrees colder. This continued di¬
minution of temperature predominates at first
over the progressive arid quality of the medium,
till the apparent moisture has become extreme,
beyond which limit the attenuated air continues
to spread drier and more pellucid. The Curve
of Gi eatest Humidity, forming the proper range
of clouds, rises about two miles above the Line
of Perpetual Congelation. The pervading clear¬
ness of the upper region, without which the
surface of our Earth would have been wrapped
in perpetual darkness, is entirely owing to the
property of rarefaction augmenting the solvent
power of the air.
From the theory of the Hygrometer, it is ob¬
vious that the instrument marks the dryness
of the ambient air only at the reduced tempe¬
rature of the wetted ball. To find the true
dryness of the atmosphere, a correction is to be
applied for the superior solvent power of its ac¬
tual temperature. With this view auxiliary
tables are constructed, which give also the
coldness of extreme humidity, or what has been
termed the Dewing Point. But it is liable to
considerable uncertainty. Placed within a me¬
tallic case, the wetted Hygrometer will gain
the zero of the scale; but when covered with a
glass shade, it will stand at 5 or even 10 degrees
of dryness, the vitreous surface, aided by heat,
abstracting the humidity from the inclosed air,
and preventing it from attaining the state of
saturation.
The Differential Thermometer was now di¬
rected to a more extensive and important sub¬
ject of inquiry,—the mode of the propagation of
heat among various bodies. Considering it as
a subtile diffusible fluid, a nice investigation of
the phaenomena might disclose the nature of its
connexion with other substances. Ascending by
a regular gradation, bodies may be distinguished
into solid, liquid, and gaseous. Suppose a cylin¬
der of silver, cased in down, had the one end
heated always to the same degree, the heat would
advance and discharge itself from the other.
If the igneous fluid were merely passive, like a
current of water, the elevation of temperature
and the inverse length of the cylinder would
follow the square of the velocity of discharge,
and not the simple ratio, as actually observed.
Heat is therefore never passive, but powerfully
attracted by its recipient. No portion of the
cylinder can receive or deposit its heat, without
simultaneously suffering a corresponding expan¬
sion or contraction. The heat is thus transfer¬
red from stage to stage, by a series of concate¬
nated dilatations and contractions; and these al¬
ternate oscillations, which are quicker in some
substances than in others, create the only impe¬
diments to the flow, that would otherwise be al¬
most instantaneous. The elasticity of heat must
be prodigious, since its weight eludes all exami¬
nation. Considering its extreme tenuity, the
expansive energy which it displays can only be
assimilated to the mutual repulsion of the par¬
ticles of Light. Every appearance, indeed, seems
to indicate that Heat is merely Light under a
latent and combined form.1
In the case of liquid substances, the commu-
* 77'^ know, combinin£ enormous elasticity with extreme diffusion, is Light itself, which when embodied
constitutes Elnnental Heat, or Fire. It is elicited from every substance by percussion or compression, by electrical agency
o c lemica a ni y. ith every species of light our vision is equally perfect, and consequently the luminous particles must
PRELIMINARY DISSERTATIONS.
768
nication of Heat is more complicated. Suppose
Heat were applied to the upper surface of a ves¬
sel containing water, its influence would gra¬
dually descend, precisely in the same manner as
if the whole mass had been consolidated; for the
warmer and dilated portions, retaining their
several positions, would continue to float in suc¬
cessive strata graduating downwards. But if
the bottom of the vessel were subjected to the
same process of heating, the water, as fast as it
grew warmer and specifically lighter, would rise
and diffuse its acquired heat. The communica¬
tion of this influence would hence become rapid,
and spread itself in horizontal strata. But
every renewal of the sentient surface must like¬
wise promote the dispersion of heat through a
fluid mass. Such is the expenditure of heat
from a hot ball plunged in the cunent 5 but in
cold still water, the heat being dispersed by two
distinct processes, the ball at first cools in a
much faster ratio than the difference of tempe¬
rature, but ultimately approximates to that ratio.
The loss of heat is, however, the same, whatever
be the nature of the surface encircled by the
water, whether of metal or glass, or cased in
linen. Water moving in a current at the rate
of only a mile an hour, will abstract four times
as much heat as if it had remained stagnant.
But when a hot ball is suspended in air, an¬
other element of dispersion now comes into play.
The air in contact becoming heated and rarefied,
ascends continually and scatters the heat. But
another portion of heat is discharged from the
cooling surface by a rapid rectilineal projec¬
tion. This emanation is best observed in sub¬
stituting a cubical vessel with different sides of
glass, or of polished or papered metal. It is
most powerful in front, diminishing laterally
as the cosine of the angle of declination. From
a surface of linen the propulsion of heat is ten
times, and from that of glass eight times greater,
than from a bright polished metallic surface.
This peculiar dissemination of heat, which from
a glass ball amounts to nearly half of the
whole discharge, is not performed by the ac¬
tual flow of the heated air, though it requires
the agency of a gaseous medium. The dis¬
charge can be collected at any distance by
a metallic reflector, and thrown concentrated
on the naked ball of the Differential Thermo¬
meter. But the intervention of a large sheet of
tin-foil obstructs the whole effect, while a very
fine screen of gauze, which would stop the pas¬
sage of streamlets of hot air, scarcely impedes
the operation. It is impossible, therefore, to
resist the conclusion, that what has been vaguely
termed the radiation of heat, consists in a certain
propulsive effort or internal tremor, excited in
the gaseous medium, analogous to the undula-
tory propagation of sound. The air can be
shown to have a closer contact with glass than
with metal, and hence the former surface exerts
a superior energy of pulsation. The interval in
the case of glass appears to be about the 500th
part of an inch. A metallic ball, coated with
the finest gold-beater’s skin, of only the 3000th
part of an inch in thickness, will have its pul¬
satory energy augmented from 1 to 6; and by
the addition of other films, this dispersive power
will successively rise to 10. .
- In air rarefied 200 times, the abdactive power
from the glass balls is reduced from 6 to 1,
while the peculiar discharge of heat at the naked
surface is depressed from 7 to 5, and that at the
crilt surface from 1 to |; the naked ball emit-
c5 # _
ting now 6| parts of heat, and the gilt one only
2|. The effects are changed in a different gase¬
ous medium. Thus, the same balls, with a vitre¬
ous and metallic surface, would discharge 31
and 25 parts of heat if immersed in hydrogen,
both of them losing 24 parts by the powerful ab¬
duction of that gas. But were the medium
rarefied about 200 times, the quantities of heat
emitted from the naked and the gilt ball would
be reduced to 13 and 8|.
The principle thus unfolded applies with ma¬
thematical precision, and illumines an exten¬
sive train of phsenomena. It likewise suggests
in all cases dart forward with the same celerity, or travel at the rate of about 200,000 miles in a second. But since atmo-
spheric air is projected into a vacuum with the velocity of only a quarter of a mile each second, the motion of Light is thus
800,000 times more rapid. Wherefore the propulsive force of Light compared with that of Air is expressed by the square of
this number, or 640 billions.” In the state of combination with Air, since it must have the same elasticity as. that fluid,
Light must hence be 544,000,000,000,000,000 times rarer than water. See Elements of Natural Philosophy, vol. i. p. 452.
DISSERTATION FIFTH.
769
vanous improvements in the practical arts, and tiful property was established by decisive e*pe-
in general economy. One of the finest modi- riments, which render the theory of the Hygro-
fications of the Differential Thermometer con- meter absolutely complete. But the perfor-
verts it into the PyroScopei by merely gilding mance of that instrument received further con-
richly one of its balls. By this alteration it is firmation and clear elucidation from the con-
fitted to measure nicely the hot or cold pulses, trast of tlie Atmmeter, which indicates with
and hence to determine the relative powers of ^ accuracy thc quantity of cxhalation from
iuel, and the efficacy of variously constructed a given SHrface in a ccrtain tUne.
chimneys. The access of heat is almost entirely A train of observations performed by this
repelled from the gilt ball, while its accumulation Hygrometer in 1810 led to the method of pro-
on the naked ball is regulated by its subsequent ducing artificial co„gelation on a large scale,
tendency to disperse through the ambient air. Having ascertained the inereased power of
The action of wind must evidently lower the a(]Ue0Us solution which air acquires as it grows
effect, insomuch that a current at the rate of only thinner, it was next suggested to combine the
eight miles an hour will reduce it to the half. action of a vigorous absorbent with the transient
To fit the Pyroscope for observations out of dryness created within a receiver by rarefac-
doors, it became therefore necessary to shelter tion. “On introducing abroad surface ofconcen-
it from the sweep of aerial streams. This pro- trated sulphuric acid, this substance was found
tectum was obtained by adopting the pendant to superadd its peculiar attraction for moisture
form of the Differential Thermometer, inclosing t0 the ordinary effects resulting from the pro-
the lower ball within a larger one of silver, and gress of exhaustion; and, what was still more
inserting the upper one in the focus of an oblong important, it continued to support, with scarce-
spheroidal cup, cut over at the remoter focus. ]y diminished energy, the dryness thus created.
It was thus converted into an JEthrioscope, which The attenuated air was not suffered, as before,
indicates the cold pulses darted at all times from to grow charged with humidity; but each por-
the higher strata of a clear atmosphere, but tion of this medium, as fast as it became satn-
more copious m summer than in winter, and rated by touching the evaporating porous dish,
stronger during the day than the night. The transported its vapours to the acid, and was
information afforded by that delicate instrument thence sent back denuded of the load, and fit-
completely elucidates the successive steps towards ted again to renew its attack. By this perpe-
a correct Theory of the formation of Dew, by tUal circulation, therefore, between the exhaling
Musschenbroeck, Dufay, Six, Wilson, Bernard and the absorbing surface, the diffuse residuum
Prei ost, and finally the late ingenious Dr Wells. 0f ajr js maintained constantly at the same state
In analyzing the process of evaporation, the 0f dryness. Heat is hence abstracted in pro¬
cold induced on the humid surface was attri- portion to this invigorated evaporation. If air
bated solely to the quickened transfer of the be rarefied only 50 times, a depression of tern-
contiguous portions of the ambient medium, perature will be produced, amounting to 80 or
But the contei minous ail must besides com- even 100 degrees of Fahrenheit’s scale.” It is
municate heat to the water by pulsation; and hence easy the hottest weather, and in every
consequently the balance of temperature would 0i;mate, to freeze a body of water, and keep it
be liable to incidental variations, if moisture, a congealed state, till it gradually wastes
with its embodied heat, were not likewise ab- away by a continual but invisible process of eva-
stracted by some corresponding process. And poration. On alargescale the operationwould be
such is the harmonious adaptation of these ele- conducted the most profitably; insomuch that a
ments. The discharge of vapour appears to be propCr system of air-pumps, put in motion by a
subject precisely to the same conditions as the steam-engine of only six horse power, might in
emission of heat, and in both cases the proximi- the climate of London produce at the rate of
ty of a vitreous or a metallic surface produces a ton of pure ice every day. Other absorbent
effects which are entirely similar.” This beau- substances besides sulphuric acid could be em-
DIS3. V. 5 E
770
preliminary dissertations.
ployed, though not so advantageously; such as
pounded trap-rock slightly roasted, parched oat¬
meal, and dry sole-leather. When water is ex¬
cluded, the dryness created within the exhaust¬
ed receiver may he turned to different useful
purposes. This process is now commonly em¬
ployed, especially on the Continent, in the nicer
chemical analyses. It can likewise be directed
to delicate preparations, which the action of
heat might derange.
The application of these various refined in¬
struments forms a sort of sera in the progress
of philosophical apparatus, and has contributed
to introduce into physico-chemical researches
a precision and delicacy unattempted before.
What seems wanted at present to complete our
knowledge of Heat, is not the vague repe¬
tition of experiments already carefully per¬
formed, but a nice investigation of several un¬
explored properties, directed with scrupulous
accuracy and on a large scale.
The systematic application of Heat has, dur¬
ing the eighteenth century, produced a complete
revolution in the mechanical arts. Air, steam,
and water are often employed as carriers of
Heat, but with very different energies. These
fluids being all raised to the pitch of boiling
water, while a current of air will transmit only
one degree of Heat, a like current of steam will
communicate 12 degrees ; but a stream of water
with the same celerity and transverse section
will, from its density and high charge, com¬
municate no less than 2800 degrees of Heat.
The alternate expansion and contraction of
fluids by heating and cooling evolves prodigious
powers. It may be shown that, with the same
expense of Heat, air itself treated in this way
exerts about three times as much force as what
is obtained from the successive formation and
condensation of steam. If such reciprocal
changes were impressed on air as rapidly as on
steam, the application of that medium would
soon supersede the most eflicient of all engines.
The expansive force of steam was finely dis¬
played by the JEolipile, an instrument constructed
in the Alexandrian School. After the revival
of science, it had been employed to set in motion
a variety of toys; but no effioient application of
steam was achieved in the seventeenth century.
It seems idle to examine the pretensions of
such projectors as the Marquis of Worcester or
Sir Samuel Morland, who caught at any sha¬
dowy schemes, to retrieve their ruined fortunes.
The person who first considered the proper¬
ties of steam philosophically was Papin, a physi¬
cian born at Blois, who visited England in 1680,
and became curator to the Royal Society. The
Digester, which he constructed next year, exem¬
plified the enormous elastic force that steam ac¬
quires when heated and confined. As a source
of power he proposed atmospheric pressure,
by forming a vacuum either by the inflam¬
mation of gun-powder or the condensation of
steam. Precluded by the revocation of the
Edict of Nantes from returning to France, he
accepted in 1687 an invitation from the Prince
of Hesse to a chair in the University of Marburg.
There he extended his plans, but found no helps
to carry them into execution. The superior
skill of English artists transferred the palm of
invention. Newcomen, a blacksmith, and Caw¬
ley, a glazier, natives of Dartmouth in Devon¬
shire, by their united studies and labours, pro¬
duced the Atmospheric or Fire Engine in 1705;
but, to prevent opposition, they associated in their
patent a naval officer, Savery, who had a few
years before contrived a very imperfect machine,
which acted however by alternate expansion and
condensation. Accident suggested the injection
of cold water within the steam-vessel, instead of
external affusion. Beighton simplified the mode
of opening and shutting the valves, and improved
the whole system of machinery; and in the
course of half a century, the Fire Engine was
adopted for raising water in all the coal-mines.
At this epoch the genius of Watt, guided by
sound judgment and urged by unremitting ap¬
plication, effected in less than forty years a com¬
plete change in the powers of mechanism. His
steady purpose was to reform the principles ol
the steam-engine, and reduce its composition to
mathematical precision. He began with per¬
forming the condensation in a vessel distinct
from the working cylinder; and he next ex¬
cluded atmospheric pressure, and merely em¬
ployed the alternate action of expanding and
contracting steam. But to pursue his career of
invention might demand a separate disquisition.
DISSERTATION FIFTH,
771
7. ASTRONOMY.
The varying spectacle of the heavenly bodies The progress which Astronomy has made
has attracted the curiosity of mankind since the since the decease of Newton may he referred to
very dawn of civilisation. In the genial regions five separate heads; 1. The investigation of the
of the East, where societies were first collected, figure of the earth, and of the other planets;
the lural inhabitants, accustomed to enjoy the 2. The determination of the anomalies of the
freshness of the nights in the open fields, con- moon’s motions, and their application to the find-
templated with wonder the sparkling radiance ing of the longitude at sea; 3. The analysis of the
of a pure canopy, remarked the groups of stars, prolonged effects resulting from the mutual dis¬
and learned by degrees to trace their successive turbing influence of the planets; 4. The improved
changes, and to connect these with the periodic theory and observation of comets; and, 5. The
motions of the great luminaries. The rudeness telescopic discoveries of new planets, and the
of such early observations was compensated by vast expansion of the catalogue of stars,
the number of the included revolutions. The oc- 1. Investigation of the Figure of the Earth and of
casion of an eclipse or an occultation served, by the other Planets.—It was easy, by combining the
disclosing the coincidence of different periods, to rotation with the length of the radius of the Earth,
rectify the elements of the planetary movements, to compute that every body at the equator must
Astronomy has grown up by a slow accumula- lose the 289th part of its weight, from the ac¬
tion of facts, continued through a long tract of tion of centrifugal force, which, being propor-
ages. It had acquired considerable accuracy in tional to the distance from the centre, will
piactice, before it received any tolerable lights exert only half such influence over the whole
fiom theory. But the art of observing has in mass; and therefore supposing this to be homo¬
modern times acquired amazing precision, from geneous, and assuming with Huygens that gra-
the very improved construction of instruments, vitation is all directed to a central point, and
and the extended methods of calculation. The equal at every distance, it thence followed that
register of a single year may now furnish more our planet is an oblate spheroid, of which the
complete data than the aggregate observations Equatorial is to the Polar diameter as 578 to
of a whole century in remote ages. 577. But Newton had already explored the
The great cultivators of astronomy are divid- question with consummate penetration ; and,
ed into two classes, accurate and inventive ob- setting out from the great principle of an attrac-
seiveis, and profound and original theorists, tion subsisting among a//the particles of matter,
Of those illustrious men who, in the lapse of had, on the hypothesis of homogeneous fluidity,
thiee thousand years, have devoted their labours shown that the equatorial column has its pres¬
to so noble a purpose, we may distinguish a sure at the centre diminished by the elliptical
few that have stood pre-eminently above their defect of the sphere, while the action of the per-
compeers; as observers, Hipparchus, Ptolemy, pendicular column is augmented from the op-
Tycho Brahe, Hevelius, Cassini, Flamsteed, posite cause; and thus a greater inequality than
La Caille, Bradley, Maskelyne, and Piazzi;—and the mere influence of centrifugal force becomes
as theorists, Copernicus, Kepler, Newton, and requisite to produce equilibrium, assigning 230
after some interval Clairaut, D’Alembert, and to 229 as the ratio of the diameter to the axis.
Euler, and in our own times the associated names This solution, however, was merely tentative,
Lagiange and Laplace. Astronomy is not the imperfection of the calculus being compen-
only the sublimest of all the sciences, but has at sated by a refined sagacity, which noted only the
last reached the highest pitch of perfection, and leading steps.
constitutes by far the grandest monument of hu- The explication of the System of the World
man assiduity and genius. from the Theory of Attraction, embraced with
772
PRELIMINARY DISSERTATIONS.
indolent acquiescence by the countrymen o
Newton, was either opposed or viewed merely
as an ingenious speculation by most of the
philosophers on the Continent.1 But a contro¬
versy now arose, which brought the accuracy of
these principles to the test of observation, and
secured their final triumph. It is evident that
the length of a degree of the meridian must be
proportional to the distance of the centre of mu¬
tual concurrence of the plummets from its extre¬
mities, or to the radius of external curvature.
In the case of an oblate spheroid, therefore,
those degrees would regularly enlarge from the
equator to the pole. But the Trigonometrical
Mensuration of France, begun by Picard in
1675, and completed in 1716 by Cassini, form¬
ing the most extensive survey yet attempted,
was found leading to an opposite conclusion in
the meridional arc, the degrees on the north of
Paris, instead of lengthening, appearing to con¬
tract about a 430th partbelow those on the south,
which would indicate an oblong figure, having
its perpendicular diameters as 96 to 95. This
perplexing result served to keep alive for some
time longer the controversy on the Continent
between the followers of Descartes and the grow¬
ing partisans of the Newtonian Philosophy. In
the meanwhile, a clock made by the famous
Graham, and carried out to Jamaica in 1732 by
Colin Campbell, was ascertained by astronomical
observations at Black-river, in the latitude of 18°,
allowing for the influence of heat on the pendu¬
lum, to go 1' 58" slower every day than in Lon¬
don. This quantity of variation Bradley found
to exceed what would suit the figure calculat¬
ed by Newton, and he was therefore disposed to
attribute the effects to some diminution of density
in the equatorial regions. James Stirling compris¬
ed the attractions of homogeneous spheroids un¬
der two beautiful theorems, which were publish¬
ed, though without demonstrations, in the Philo¬
sophical Transactions for 1735. About the same
time Bouguer noticed some restrictions essential
to the rigorous solution of the problem; but
now Maclaurin took a most commanding view
of the subject, and produced, first in his famous
Dissertation on the Tides, and again more fully in
his Treatise of Fluxions, printed in 1742, a geo¬
metrical investigation, distinguished by its ori¬
ginality, clearness, and superior elegance. This
illustrious mathematician established, from the
law of gravitation, the stability of a fluid sphe¬
roid revolving about its axis in a certain time,
proved that every point within the mass would
be pressed equally on all sides, and showed that
even the superadded attractions of the sun and
moon could not disturb the internal equilibrium
of our Earth. The conclusions applied likewise
to the other planets, and embraced the theory
of the tides. But his profound investigation like¬
wise disclosed several general theorems, which
have greatly simplified and extended the science
of Hydrodynamics.
The most refined theory, thus confirming the
Newtonian figure of the Earth, again recalled
the attention of philosophers to the actual sur¬
vey of its surface. The French triangulation
being resumed in 1740, an error was detected
in the measurement of the base, and another
not less considerable in the observation of the
meridional arc; but to rectify the various de¬
tails required the labour of several years, nor
did the work terminate before 1754. In the
extent of above eight degrees, their lengths ap¬
peared regularly to increase, from Perpignan to
Dunkirk, by about the 1730th part; marking
evidently the oblateness of the spheroid.
But it was most desirable to resolve the ques¬
tion on a larger scale; and the Academy of Paris,
urged in 1733 by Condamine to send a party to
measure a degree under the Equator, adopted
his project with zeal, and fortunately obtained
the sanction of government. After all the pre¬
parations were made, the Academicians, Con-
1 In a letter written from Basle on the 22d November 1729 by Nicholas Bernoulli, to his friend dames Stirling a
don, with whom he had become acquainted several years before, when the former was professor at Padua, and the a er a
teacher of Mathematics in 'Venice, he confesses, with regard to Machin’s attempt to illustrate the Lunar Theory, tna le a
not yet taken the trouble to read the third book of the Principin. Pauca quidem in co intelligo, quia nullam adhuc operam
collocavi in lectionc teftii libri Principiorum D. Ncwioni. Stirling, in his answer, dated in September 1730, frankly remar s,
that “ it is somewhat strange, that though the Principles have been published above 40 years, nobody has read further ran
the two first books, although they be barely speculations, and were written for no other reason but that the third might be un*
derstood.” (From a collection of Stirling’s papers in the possession of Mr Irving, one of the Judges of the Court ot Ses¬
sion, under the title of Lord Newton.)
DISSERTATION FIFTH.
773
damine, Bouguer, and Godin, in May 1735 sailed
from Rochelle to Peru, where they joined Juan
and Ulloa, two naval officers deputed by the
king of Spain. The whole company assembled
in the month of June in the following year at
Quito, almost under the Equator, and arranged
their plan of operations. They chose a valley
of the Cordilleras running above 200 miles south¬
wards from that city, and inclosed on both sides
by the loftiest ranges of the Andes. Divided
into two troops, they carried a series of triangles
along the flanks and summits of those stupen¬
dous mountains covered with eternal snows, and
connected the reticulation with the base mea¬
sured below. In pursuing their laborious task,
the observers had to encounter the greatest dif¬
ficulties, and to suffer privations of every kind,
owing to the severity of the climate and the
total want of accommodation, joined to the con¬
tinual impediments occasioned by the supersti¬
tion of the natives and the pilfering habits of
the Indians. But resolution and perseverance
at length overcame the multiplied obstacles,
though no fewer than eight years were consum¬
ed in completing with elaborate care and accu¬
racy the different operations undertaken. Con-
damine was a man of an ardent and active mind,
and persuasive address; Godin, an excellent ob¬
server ; but Bouguer combined the character of
a deep and original thinker, with the talent of
invention, unwearied application, and an ex¬
tended acquaintance in the various pursuits of
philosophy and science. The Academicians were
ably assisted by their Spanish associates, though
each performed separately his own calculations.
It was reserved, however, for Bouguer to give
the complete narrative of all the various opera¬
tions, in his Treatise on the Figure of the Earth,
not published till 1749, but one of the most va¬
luable scientific works that has ever appeared.
Besides amply discussing the principal question,
it investigated incidentally the effects of local at¬
traction on the plummet, the length of the pen¬
dulum, the theory of refractions, the rules of
barometrical measurements, the limits of perpe¬
tual congelation, the intensity of the solar rays
at different elevations, and the celerity of sound
as affected by heat. He concluded that the Earth
is not only an oblate spheroid, but so consider¬
ably flattened as to have its equatorial diameter to
its axis in the ratio of 179 to 178; and he thence
inferred that the central parts must be four or
five times denser than the superficial crust.
In the mean time, it being foreseen that the
mensuration of a degree in Peru would be ne¬
cessarily retarded, the celebrated Maupertuis, a
person of agreeable attainments, though not
very profound in science, prevailed with the
French minister Maurepas to dispatch another
company, which he reluctantly consented to
lead, for a similar purpose to the Arctic Circle.
His associates were Monnier, Camus, Outhier,
and Clairaut, already distinguished by the pre¬
cocity of his fine mathematical genius. They
arrived at Stockholm in June 1736, and were
joined by Celsius, the professor of astronomy at
Upsal, who had brought from London Graham’s
zenith sector and transit instruments. Having
settled their general plan, they proceeded to the
bottom of the Gulf of Bothnia, and selected
Tornea for the principal station. From that
small capital they stretched a chain of triangles
along the wooded heights to the top of Kittis, a
distance however not exceeding 60 miles. Work¬
ing with great spirit and activity, and having
no difficulties to encounter but the severity of
the climate, they observed the angles from the
several stations during the remainder of the
summer, determined the celestial arc in autumn,
and measured the base along the frozen surface
of the river Muonio in the early part of winter.
The length of a degree of latitude at the Arctic
Circle was found to be 57,419 toises, or 349
toises longer than the corresponding measure at
Paris, which gave the ratio of 178 to 177 for
that of the Equatorial and Polar diameters, al¬
most the same as the result of the more exten¬
sive operations afterwards in Peru. Maupertuis,
having with such expedition ascertained the ob¬
lateness of the Earth, and assigned a depression
still greater than had been computed by Newton,
returned triumphant to Paris in the spring of
1737. But this arctic triangulation, betraying
evident marks of haste, became suspected after¬
wards of inaccuracy; and, at the suggestion of
Melanderhjelm, the Swedish academy, about the
PRELIMINARY DISSERTATIONS.
774
beginning of the present century, sent Svan-
berg, with proper assistants, to resume the ope¬
rations, who not only rectified the former obser¬
vations, but carried the mensuration about 40
miles farther north.
It was then determined that the length of a
degree in Lapland is only 57,209 toises, which,
compared with Cassinis coriected measure m
France, reduces the oblateness to the 290th part
of the Earth’s axis. But a more accurate result
is obtained from the comparison of the distant
observations made under the Equator and at the
Arctic Circle, the perpendicular diameters of the
terrestrial spheroid being in the ratio of 302 to
301. Still greater nicety has been attempted
by Littrow, who, on re-computing the degree in
Lapland, reduced it to 57,168 toises, which gives
an oblateness of only —J—.
Other determinations of a degree of latitude
have been made at different parts of the Earth’s
surface, the most remarkable of which may be
noticed. La Caille, one of the best observers,
and the most accurate and laborious of astro¬
nomers, rectified the French triangulation du¬
ring the years 1739 and 1740; nor did the ex¬
treme severity of that memorable winter prevent
his carrying forward these operations over the
lofty mountains of Auvergne. He proved decid¬
edly that the degrees of the meridian regularly
increase from the south to the north of France.
Some years afterwards he went to the Cape of
Good Hope, chiefly for the purpose of framing
a catalogue of the stars of the Southern Constel¬
lations ; but his ardour and extreme activity en¬
abled him to accumulate other valuable celes¬
tial observations. Having performed the task
he had proposed, and the ship not arriving to
carry him home, La Caille was tempted to em¬
ploy the time thus afforded in measuring by
his single exertions a degree of latitude. This
he found, on the parallel of 34°, to be 57,037
toises, and therefore of the same length with a
degree as far north as 49° in France; which
seems to indicate not only a flatter outline, but a
difference of internal constitution in the southern
hemisphere. The accuracy of the measurement
itself, however, has been strongly suspected.
In 1750 and the two following years, Bosco-
vich and his associate La Maire measured an arc
of two degrees in the Papal States, and fixed the
length on the parallel of 43° at 56,979. Beccaria
traced a single degree in Piedmont, and found
the opposite attractions of the lofty sides of the
Alps had such influence in deflecting the plum¬
met, as to render the northern half of the mea¬
sure a 69th part longer than the southern.
After a pause of near forty years, the mensu¬
ration of the Earth was revived with increasing
ardour and on a grander scale. The object first
contemplated was merely to settle the difference
of longitude between the observatories of Green¬
wich and Paris, by connecting them with a se¬
ries of triangles. General Roy directed the
English survey in 1784, while similar operations
were conducted by Cassini in France. The Re¬
volution soon followed, and prepared the public
mind for the reception of every bold project. It
was now proposed to adopt a universal and
permanent system of weights and measures
drawn from nature, the unit of lineal' extent
being the thousandth part of a centesimal minute,
or the ten millionth part of the quadrantal arc
from the Pole to the Equator. To obtain this
standard, it had been resolved to carry a chain
of triangles over the whole extent, from Dunkirk
to Barcelona; which was performed during the
most eventful period of general excitement and
commotion, by the profound sagacity, persever¬
ance, and undaunted zeal of Delambre,1 joined to
1 Born at Amiens on the 19th September 1749. Being designed for the church, he studied the ancient languages in the
Gymnasium of his native city, first under the Jesuits, and afterwards under the tuition of the poet Delille, to whom he became
warmly attached. At a ripe age, he was invited to the study of astronomy by Lalande, and soon adopted as his favourite
pupil. In 1785 he began the vast series of his scientific labours, which occupied the rest of a long life. Without aiming
at originality, Delambre produced very complete and valuable works, pursued his immense calculations with scrupulous
nicety and incessant application, and distinguished himself as a most accurate, skilful, and indefatigable observer. He
sought precision merely, and was rather indifferent about the elegance of his formulas or composition. Yet he was an ex¬
cellent Greek scholar, well acquainted with the principal modern languages, and indeed a man of general erudition. Gt an
amiable disposition, with fixed principles of integrity joined to simple habits, he passed through all the storms of the Be-
volution with a blameless character. He obtained his full share of the honours and distinction which France so liberally
bestows on those eminent in science, and died universally regretted, on the 19th of August 1822.
DISSERTATION FIFTH.
775
Mechain.1 After completing1 this operation, they
measured abase of seven miles in length near Paris,
and another of verification, somewhat shorter,
on the road from Perpignan to Narhonne. The
register of all the observations was in the spring
of 1799 submitted to a sort of congress of scien¬
tific men assembled in the French capital, who
having examined and repeated the various calcu¬
lations, and compared the celestial arc with the
mensuration in Peru, adopted the 334th for the
oblateness of the earth, and determined the dis¬
tance of the pole from the equator to be 5,130,740
toises.
Mechain, anxious however to extend the me¬
ridian as far as the Balearic Isles, again repaired
to Spain, and conducted a series of triangles over
the savage heights from Barcelona to Tortosa,
when, exhausted by incessant fatigues, he caught
an epidemic fever, which proved fatal in Septem¬
ber 1805. The operations were continued by
his young but very able successors, Biot and
Arago, who terminated the meridional arc at the
isle of Formentera in 1807. This extension of
the chain scarcely altered in the slightest man¬
ner the former conclusion.
The English survey, being designed merely
for the construction of an accurate set of maps,
suffered some interruption by the death of Gene¬
ral Roy, but was resumed with spirit in 1793,
under the skilful direction of Colonel Mudge,
who carried the triangulation as far as the north
of Scotland; and since his decease in 1820, the
work has been transferred to Ireland by his per¬
severing assistant and successor Colonel Colby.
The method of observing is now improved, and
all the refinements of modern art have been ex¬
hausted in the mensuration of a new base.
Those operations have no doubt proceeded
very slowly, and yet the results of the first series
were perplexing, the three degrees measured
from Bunnose to Clifton successively contract¬
ing instead of lengthening, and therefore indicat¬
ing, like the earlier observations of Cassini, an
oblong figure of the Earth. The whole arc agrees
exactly with the last triangulation of France, in
giving an oblateness of only the 334th part; but
whether the intermediate discrepancies should be
imputed to an error of azimuth, or to the pro¬
bable derangement from local attraction, still
remains undecided.
In 1802 and 1803 Colonel Lambton measured
a degree of the meridian in the East Indies, and
found, at the latitudes of 9° 35', 12° 3', and 16° 35',
the lengths to rise successively to 60,477, 60,490,
and 60,512 fathoms. Hence Delambre deduced
the oblateness of the terrestrial spheroid to be the
206th part. But Rodriguez, an able Spanish ma¬
thematician, who had already criticised the obser¬
vations of Mudge, detected various mistakes in
Lambton’s calculations, which being rectified,
reduced the depression of the Earth to the 320th
part.
Since the spheroidal figure of our planet is
evidently subject to great irregularities, we are
led to inquire, whether it be a solid of revolution
and have true circles for its parallels of latitude.
Cassini and Maraldi seem to have been the first
to solve this interesting question. They found,
in 1734 and 1735, a degree of longitude at Paris
and at Strasburg to be 36,676 and 37,745 toises,
1 Born at Laon 16th August'l744, the son of an unprosperous architect, who could hardly educate him in the same pro¬
fession. The youth supported himself, and even aided his father, by teaching mathematics, and made such proficiency in
astronomy as to attract the notice of Lalande, by whose warm and active patronage he soon obtained the office of hydro-
grapher to the Marine at Versailles. Though he had not the talent of invention, he became an expert, patient, and correct
calculator. He was, besides, a very nice and accurate observer, and applied himself particularly to the search of comets, and
the computation of their orbits. In 1784 he was joined to the commission for adjusting the difference of longitude between
the observatories of Paris and Greenwich; and when the Constituent Assembly had resolved to adopt a grand metrical system
founded on the length of the meridional arc, he was appointed to measure the southern portion of it from Barcelona to Kodez.
He conducted his operations with great celerity and success ; but, inspecting a new engine constructed by a friend at Barce¬
lona, he met with a dreadful accident, which had well nigh proved fatal. After a slow convalescence he resumed his labours;
but every thing now combined to dishearten him,—the Avar with Spain, the ravages of the yellow fever, and the news of the
reign of terror in France. After moderation had revived, Mechain with much reluctance was prevailed on to come to Paris ;
but strongly pressed the expediency of extending the measurement two degrees farther into Spain, and insisted on carrying on
that work himself. This pertinacity was not explained till after his death, when it appeared that he had concealed a discrepancy
occurring in the rectification of his observations, which, without acknowledging the error, he no doubt hoped to remove by
subsequent operations. After experiencing many difficulties, he vigorously renewed his labours in Valencia ; but his mind
was depressed by anxiety for his reputation, and alarms at the spread of contagious disease. This mental prostration
favoured its attack, and he expired of yellow fever in his retreat at Castellon de la Plana, on the 20th September 1805.
776
preliminary dissertations.
and therefore considerably less than what belongs
to a perfect sphere. But the most accurate ob¬
servation of this kind was made by La Caille in
1740, from the top of a hill near Aix, to a signal
on a high tower above the Rhone, about 96 miles
remote, where he caused ten pounds of gunpowder
to he fired, and found by the instantaneous blaze
the difference of time between the two meridians,
and then measured trigonometrically along the
plain of Arles the intermediate distance, which
gave 41,858 toises for a degree of longitude, or
260 toises less than a globular form would re¬
quire. Lambton estimated the degree of longi¬
tude on the parallel of 12° 82' to be 61,061
fathoms, or 57,294 toises; but his observations,
and calculations seem not entitled to much con¬
fidence. The latest and most accurate measure¬
ment of a perpendicular to the meridian was
performed in 1823, near Geneva, by Colonel
Brousseaud, of theFrench engineers, in connexion
with the late ingenious Professor Pictet, while
the skilful astronomers Plana and Carlini com¬
pleted a similar operation on the plains of Italy as
far as Padua. The first, being compared with the
arc from Greenwich to Formentera, gave a 271st
part for the oblateness of the Earth; but, when
conjoined with the Italian prolongation, it redu¬
ced the quantity of depression to a 292d part of the
equatorial diameter. It must be confessed, how¬
ever, that the accuracy of these conclusions has
been contested by some of the ablest calculators.
From a skilful combination of the five prin¬
cipal measurements, in Peru, India, France,
England, and Lapland, Mr Ivory has, by the
method of the least squares, deduced for the
oblateness of the Earth, and shown that the
corresponding elliptical meridian agrees with
the best observations. The result would have
been still more satisfactory, had the English
survey comprised the whole extent of the island.
But a very small portion of the arc is comput¬
ed, and the fruits of twenty years’ expensive
operations are not yet communicated to the
public. Meanwhile, other surveys, conducted
after the most scientific manner, are now far ad¬
vanced ; in Lower Saxony by Gauss, in Holstein
by Schumacher, in Swabia by Bohnenberger,
and in Russia and Finland by Struve. These
continental observations must throw much light
on the form and constitution of our planet.
Local attraction may deflect the plummet from
its vertical position, but it can have little effect
on its general gravitation. TLhe vibration of a
pendulum, therefore, promises a readier and
surer method of discovering the figure of the
Earth. The difficulty is to ascertain the length
with extreme precision, or the distance between
the point of suspension and the centre of oscilla¬
tion. The pendulum constructed by Borda
seemed to require little correction. It consisted
of a slender iron wire about 13 feet long, termi¬
nated by a small cap of copper, to which was
nicely fitted a ball of platinum about an inch
and half in diameter. The vibrations were per¬
formed in two seconds and continued for twelve
hours, the number being reckoned from the dis¬
tant coincidences with the pendulum of an astro¬
nomical clock. Mathieu has computed, fiom six
observations made with this instrument along
the meridian from Dunkirk to Formenteia, the
depression of the terrestrial spheroid to be
1 But from a general comparison of all
298-2
the various measures over the surface of the
Earth, Laplace reckoned this quantity, only
1 _ It has been alleged, indeed, that the
335-78
illustrious author had committed a mistake in the
taking out of a logarithm, which being corrected
would give ~
The Convertible Pendulum constructed by Cap¬
tain Kater, on the beautiful principle first de¬
monstrated by Huygens, that the point of sus¬
pension and the centre of oscillation are intei -
changeable, seemed to promise greater accuiacy,
and was proposed by the inventor as furnishing
an invariable standard of linear measure. So
sanguine were his expectations, indeed, that he
believed it could not occasion an error of the
400,000thpart of the whole. But the observations
which he made with this pendulum, at different
points in an arc of ten degrees extending to Shet¬
land, display no such harmony, for the resulting
DISSERTATION FIFTH.
777
oblateness of the Earth varies from the extremes,
between —^— and —^—. It has been custom-
397-5 229-6
ary to attribute the discrepancies to the influence
of local attraction, but they are frequently too
considerable for the most exaggerated hypothesis
to explain, and must be referred either to the
inaccuracy of the observer or to the imperfection
of the instrument employed. Calculators, in
their endeavours to harmonize such observations,
can seldom proceed dispassionately; they are apt
to modify some of the data, and arbitrarily to re¬
ject others as anomalous or liable to suspicion.
Parry's experiments with the convertible pen¬
dulum at London and Melville Island gave an
oblateness of —^—. The numerous observations
312-6
made by Freycinet and Duperrey, in their voyages
of discovery, indicated, for both the northern
and southern hemispheres, a depression between
and-i-. Captain Sabine concluded, from his
own combined observations, that the quantity is
—^— But Mr Ivory, whose decision is entitled
QQQ./i J
to the greatest confidence, has, from a critical
examination of those data, concluded the ellip-
ticity to be
1
300’
and found the same figure to
agree both with the measures along the meridian
and those perpendicular to it. To arrive at so
satisfactory a result, however, it was necessary
to exclude nearly one-sixth of all the observa¬
tions, those made near the equator being the
most discordant. Such aberrations leave con¬
siderable distrust, which is not removed by in¬
specting the later observations. But it were idle
to affect extreme precision, where the discre¬
pancy amounts sometimes to a six thousandth
part. The convertible pendulum appears liable
to different sources of error, and though it may
furnish an approximation to the determination
of the terrestrial spheroid, it can hardly be ex¬
pected to reach the accuracy and certainty re¬
quisite for a metrical standard.
We may now revert to the analytical investiga¬
tion of the figure of the Earth. Clairaut had given
the elements of the solution previous to his set-
DISS. Y.
ting out on the expedition to the Polar Circle.
But after his return from that memorable achieve¬
ment, he resumed the disquisition; and adopting
the geometrical discoveries of Maclaurin, he pro¬
duced the completest analysis of the problem, in
his very ingenious work which came out in 1743.
He determined the equilibrium of a revolving
spheroid, when composed of concentric layers
of different densities, assuming the deviation
from the spherical figure to be very small.
Clairaut showed that the particles of the same
density must always range in distinct strata,
to which the resulting force that urges them is
perpendicular; and found the general equations,
simplified afterwards by Euler, for assigning the
stability of the fluid mass. But it was not until
1784 that Legendre gave a direct analytical so¬
lution of the problem, in the case of a homogene¬
ous spheroid approaching nearly to a sphere,
which required the single condition that gravity
should act perpendicularly at the surface. Laplace
afterwards simplified and completed this investi¬
gation, by extending it to elliptical strata of dif¬
ferent densities. The solution, however, was not
rigorous, and merely exhibited an approximation,
by leaving out the cubes and higher powers of
the series. The numerical results yet vacillate
between the proportions announced by Huygens
and Newton. It is indeed remarkable, that a sub¬
ject which has exercised the efforts of sublime
genius, should have yet derived so little real
elucidation from the stores of the higher calcu¬
lus. The theorems of Maclaurin still far trans¬
cend the most elaborate displays of analytical
research. But his illustrious countryman Ivory,
undismayed by such formidable difficulties, has
lately revived the discussion, and, examining
more narrowly the physical conditions of the
problem, and thus restricting the differential
equations, he has with felicitous address suc¬
ceeded in conducting his analytical procedure to
a definite result. Britain has therefore the
honour both of originating the discovery of the
true figure of the Earth, and of completing its
demonstration.
But the Earth’s oblate shape is likewise de-
ducible from certain small mutations in the orbit
of the moon. The attraction exerted by our satel¬
lite on the protuberant matter at the Equator occa-
5 F
778
PRELIMINARY DISSERTATIONS.
gions the Nutation of the terrestrial axis; and this
action being reciprocal, the moon suffers a corre¬
sponding alteration both in latitude and longi¬
tude. Such is the wonderful precision attained
in astronomical observations, that Burg, one of
the most expert calculators in our day, computed
at the request of Laplace, from very numerous
data, the ellipticity of the Earth to he respective-
lv__L_and . The motions of the lunar
y 304-6 305
nodes and perigee have been shown by the same
profound philosopher to indicate a similar con¬
clusion. The form of the Earth is hence flatter
than that of a homogeneous spheroid; and this
difference appears to arise from the increasing
density of the internal mass caused by superin¬
cumbent pressure. A like character belongs to
Jupiter, the largest planet in our system; for his
axes, which, from the combined action of gravity
and centrifugal force, should have the ratio of 41
to 36, are observed to be only as 14 to 13, or
41 to 38, thus evincing the great compression
of the internal mass.
The discussions relating to the figure of the
Earth led to an examination of the Theory of the
Tides, the great outlines of which had been
likewise traced by Newton from the Law of
Gravitation. The Academy of Sciences at Paris
selected the complete investigation of this difficult
subject for the prize offered in 1740; and never
did three more illustrious competitors contend
for the honour of an award, which was shared
among Maclaurin, Euler, and Daniel Bernoulli.
The dissertation of our countryman, as already
observed, was pre-eminently distinguished by the
new and beautiful propositions which it contained.
Supposing the Earth were at rest and covered with
a shell of water, any remote body, attracting the
anterior surface with greater force than the lateral
mass, and this again with greater force than the
posterior surface, would evidently cause the fluid
to rise on the opposite sides and form a prolate
spheroid, having its longer axis directed to the
disturbing agent. But this influence was proved
by Newton to be inversely as the cube of the
distance. Though the sun has above twenty
million times more matter than the moon, yet
being four hundred times more remote, he there¬
fore exerts three times less influence in raising
the tides. While the ocean swells out both
under and opposite to the sun, it turns another
trebly more protuberant spheroid towards the
moon. These elevations, differently combined,
produce the variable heaving of the waters which
constitutes the general tide. The conditions of
equilibrium are easily determined; but it is a
most arduous research to distinguish the several
effects of the rotation of the earth and the re¬
volution of the moon, in retarding and modify¬
ing the oscillations of the irregular aqueous ex¬
panse. Such was the problem which so long
exercised the genius and penetration of Laplace.
He began the consideration of this intricate sub¬
ject in 1774, and resumed his investigation re¬
peatedly afterwards. Having obtained a gene¬
ral expression for the oscillations of the ocean,
he distinguished these into three separate swells,
obeying different periods of succession. The
tides of the first class depend on the motions of
the sun and moon, the variations of the dis¬
tances, and the change of their declinations.
The stream tide occurs at the interval of a day
and a half after the conjunction or opposition,
the lunar swell at first preceding the solar, but
falling back at the next two returns, till at the
third accession it combines with the latter. The
decrease of consecutive tides is about a third
faster at the conjunctions which happen in the
equinox than at those in the solstice, and nearly
twice as rapid at the quadratures that occur in
the equinox as at those in the solstice. Similar
consequences result from the alterations in the
right ascension and the declination of the sun
and moon. All these conclusions of a refined
theory are singularly confirmed by a critical and
very laborious examination of the observations
made for a series of years at the port of Brest.
The second sort of oscillations is occasioned by
the diurnal change of the elevation and depres¬
sion of the sun; so that in midsummer, when
the declination is greater, the stream tide at
Brest rises seven inches higher in the morning
than the following tide towards evening. This
divaricating tide has no visible influence however
on our shores; and to explain the equal swell of
the waters during the day and the night, Laplace
refers it to the retardation from a current of a
certain uniform depth, which he estimated at
DISSERTATION FIFTH.
779
four leagues, or eleven English miles, but has
since greatly reduced it, without venturing to as¬
sign the true measure.1 The third kind of tides,
depending on the greater revolutions of the
moon, have much longer periods; but their in¬
fluence, however small, is traced through the
observations. The immense calculations of
Bouvard have detected every varying phasis of
the law of Universal Attraction; but a closer
approximation is still wanted to unfold sepa¬
rately all the terms of the disturbing forces.
Some of the minute shades are indicated by a
fine application of the Doctrine of Chances, and
a similar process renders highly probable the ex¬
istence of corresponding fluctuations in the mass
of our atmosphere.
2. Mathematicians were at length prepared
for investigating dispassionately the application
of the great principle of attraction to all the va¬
rious motions of the heavenly bodies. It had ex¬
plained with beautiful simplicity the revolutions
of the planets about the Sun, and of the satel¬
lites around their primaries. But to distinguish
its operation in the anomalies of the general sys¬
tem was a most arduous undertaking. Astro¬
nomers indeed had already, from a diligent and
skilful comparison of distant eclipses, detected
the principal irregularities of the Lunar Motions.
Hipparchus and Ptolemy discovered what are
called The Equation of the Centre and the Erec¬
tion; and after an interval of fourteen centuries,
Tycho and Kepler added the Variation and An¬
nual Equation. Newton not only expounded all
these anomalies by the simple law of gravitation,
but, probably without any helps from observa¬
tion, discovered six more auxiliary equations.
The Theory of the Moon, which crowns his im¬
mortal Principia, is a production of genius, sa¬
gacity, and invention, almost superhuman. He
ascends with admirable order from the easier to
the more difficult problems, reducing them al¬
ways to greater simplicity; he pursues his ap¬
proximations with consummate address, and
seldom passing the clear bounds.of geometry,
or entangling his demonstrations in the laby¬
rinth of Algebraical formulce, he advances with
elegance and apparently without effort to the
disclosure of the most recondite truths. But it
must be confessed that, in his eagle flight, he
was satisfied with taking a general glance of the
objects, and seldom stooped to mark the details
or investigate the grounds of his calculations.
He no doubt managed the research by estimat¬
ing the different elements of perturbation, and
supplying, as in other cases, the deficiency of
the analytical process by a selection of circum¬
stances, and the nice balancing of errors. The
illustrious author himself candidly admitted the
imperfection of his Lunar Theory; but what
seems truly astonishing is, that in such a novel
and arduous attempt he should have been guilty
of so very few mistakes or omissions. The Eng¬
lish commentators contributed very little to its
extension and improvement. Machin, profes¬
sor of Astronomy in Gresham College, secre¬
tary of the Royal Society, and esteemed an ex¬
pert calculator, speaks of it with flippancy, and
seeks only to annex a vague hypothesis, which
leads to an arbitrary geometrical construction ;
“ especially,” says he, “since the greatest part of
the Theory of the Moon is laid down without any
proof, and since those propositions relating to the
Moon’s motion which are demonstrated in the
Principia do generally depend upon calculations
very intricate and abstruse, the truth of which
is not easily examined, even by those that are
most skilful; and which, however, might he easily
deduced from other principles and hints of cal¬
culations which he has not produced.” 2 He ad¬
mits, indeed, that Theory gives only half the
motion of the Lunar Apogee.
The first who improved and expanded the
Newtonian Theory of the Moon was Calandrini,
professor of Mathematics at Geneva, who super¬
intended the printing of the Jesuits’ edition of
the Principia in 1739 and 1742. He investigat¬
ed by a direct method the principal lunar equa-
, . 1 Jri thy last edition of the Mtcanique Celeste he seems to have silently abandoned his calculation altogether, contenting
him sell with adopting the conjecture of the geographer Varemus, that the depth of the sea must bear some proportion to
the altitude of the shore. * n r r v r.
2 The Laws of the Moon's Motion according to Gravity, a very short tract appended to Motte’s Translation of the Principia
which came out in 1729.
780
PRELIMINARY DISSERTATIONS.
tions, and likewise the smaller inequalities
which Newton had left undemonstrated. He
revised the investigation of the motion of the
apsides, hut was mortified to find his calcula¬
tions gave only half the quantity derived from
observation. The honour of confii ming the
Newtonian Theory of the Moon was reserved,
however, for our own countrymen. Dr Stewart,
the successor of Maclaurin in the University
of Edinburgh, discovered the true motion of
the line of apsides by a simple and beautiful
geometrical procedure, in which Ids inventive
penetration happily supplied the flexibility of
the modern calculus. About the same time
Walmesley,1 an English Benedictine Monk,
who afterwards attained the rank of Catholic
Bishop and Apostolic Vicar, but had been com¬
pelled by religious and political bigotry to reap
the advantages of a foreign education, produced
in 1749, at the early age of 27, a correct analy¬
tical investigation of the motion of the Lunar
Apogee, which he extended and completed in
1758.
In the meanwhile, the profoundest mathema¬
ticians were directed to the right points of at¬
tack, and incited to exert all their penetration
in exploring the influence of the System of Gra¬
vitation, by the prizes proposed by the learned
associations on the Continent. Clairaut began
his examination of the Lunar Theory in 1743.
At first he was content with merely studying
the Newtonian procedure, and converting it
into analytical expressions; but as he became
more familiar with the subject, he pushed his
investigation further, and in 1747 comprised all
the subordinate motions of the Moon under the
famous general problem of the Three Bodies.
But, after a prodigious exertion of ingenuity
and perseverance, it was mortifying to find his
solution assign for the variation of the Lunar
Apogee only half the measure established by
observation. Eider and D’Alembert, nearly
about the same time, arrived at a similar con¬
clusion. The followers of Newton were sur¬
prised and mortified at the result, while the ad¬
herents of the Cartesian system already began
to exult in the prospect of the immediate fall of
such a towering rival. In this dilemma, Clairaut,
to reconcile the result of analysis with the actual
phenomena, proposed, without abandoning the
great principle of attraction, to modify its recipro¬
cal gradation of intensity, by annexing to the
square of the distance a small subsidiary term de¬
pending on its cube. This correction might be
sufficient, from the proximity to the earth, for
adjusting the Lunar motions, while it could have
no sensible influence, he conceived, in affecting
that duplicate ratio which directs the remote
revolutions of the planets about the sun. But
Buffbn, who began his career with the study of
mathematics, showed, from the properties of the
roots of equations, that such a modification of
the law of gravity involved what appeared an ab¬
surd consequence, that a body would be attract¬
ed equally at different distances. Clairaut was
not shaken by this argument, which he con¬
sidered as only metaphysical; yet so much
discussion had been provoked, that, anxious
to remove all doubts from the subject, he re¬
sumed his investigation, and pursued it with
incredible labour and resolution. Carrying the
approximation much farther, by computing the
values of the higher terms of the series, and
reiterating the process, he found the combined
integrals to give exactly the double of the former
result. This satisfactory conclusion, which con¬
firmed the simple law of gravity, and restored
the harmony of the universal system, was an¬
nounced early in 1749. The bare mention of
the fact was enough for the inventive powers of
Euler, who, by quite a different procedure, soon
obtained the true variation of the Lunar Apogee.
If D’Alembert needed some previous information
to put him in the right train, he pushed his cal¬
culations to wider extent, and approached still
nearer the absolute effect. It would seem that,
during this eager competition, the advances of
Stewart and Walmesley were overlooked. But
their countryman Thomas Simpson ventured,
though considerably in the rear, to travel partly
over the same ground of inquiry.
This remarkable coincidence among the first
1 Dr Charles Walmesley, horn in 1722: In his latter years he resided at Bath, and took to the study of mystic theo¬
logy, having written on the Revelations, and explained the Vision of Ezekiel. His papers were burnt by an antipopish
mob in 1780, and he died in 1797*
DISSERTATION FIFTH.
781
mathematicians of the age extinguished for ever
any lurking suspicion of the Law of Universal,
Attraction. The great object of scientific re¬
search was henceforth to direct its application
to the celestial motions and the improvement of
practical astronomy. The rectification of the
Lunar Tables, now become of such importance
in the practice of navigation, was the fruit of
those arduous calculations. Clairaut bestowed
intense application, and digested his results into
a clear form; he skilfully employed some data
furnished to him by La Caille for adjusting the
auxiliary equations, and thus produced Tables
of the Moon’s motions distinguished by their
very superior accuracy. D’Alembert proceeded
more slowly and neglected such aids, so that his
Lunar Tables never obtained estimation with
astronomers. Euler excelled both his illustrious
rivals in the wonderful command of the powers
of calculation ; he worked with ease and rapidi¬
ty, and his fertile invention continually supplied
new resources and suggested other paths of ad¬
vance. He suspended for a few months the
further improvement of the Lunar Theory, and
at the invitation of the Academy of Sciences at
Paris, analyzed with all the fulness of research
the influence of the mutual disturbance of the
planets Jupiter and Saturn. But aiming at still
higher perfection, after the interval of a few
years he resumed this investigation, simplifying
and greatly extending it. In the mean time he
had computed a set of Lunar Tables, which he
disposed in a clear method, having discovered the
co-efficients of the several equations from theory
alone.
About this time Mayer of Wiirtemburg began
to distinguish himself as one of the ablest and
most ingenious astronomers that has appeared
in any age. In 1751 he had been appointed di¬
rector of the observatory at Gottingen; and in
this situation, encircled by foreign troops, and
exposed to the danger of powder magazines, he
yet laboured with such intense and enthusiastic
ardour as to shorten his days. His efforts were
mainly directed to the improvement of the Tables
of the motions of the Sun and Moon. These
elements he derived from a discussion of nu¬
merous observations of eclipses and occulta-
tions, and he borrowed little from theory, though
he preferred the arrangement of the elements
adopted by Euler. He was the first who em¬
ployed the method of conditional equations to
find the true values of the co-efficients. His
Tables Were inserted in the Gottingen Trans¬
actions; and after the most sedulous correction,
he sent them in 1755 to London, for the pa¬
tronage of the Board of Longitude. At his
death in 1762 he left two copies, greatly im¬
proved, one of which his widow transmitted to
that scientific body. After long and protracted
deliberations, the modified prize of L.3000 was
at last awarded to his family, with a present
of L.300 to Euler, for his excellent formulas.
But another more complete copy having been af¬
terwards presented, the Board of Longitude be¬
stowed an additional reward of L.2000 at the in¬
stance of Dr Maskelyne, who zealously under¬
took the charge of editing those Tables in 1770.
The exertions of the continental mathemati¬
cians were now successfully directed to the in¬
vestigation of the disturbing influence or mutual
perturbations of the larger and nearer planets.
Euler in 1747 sent to the Academy of Sciences
at Paris a most ingenious memoir on the de¬
rangement of Saturn’s motion, occasioned by
the superior attraction of Jupiter. It was not
only the first solution of the problem, but the
simplest and most direct, referring the forces
exerted to three perpendicular co-ordinates.
He then discovered the beautiful principle in
celestial mechanics, that there exist really no
secular equations, but that all the deviations from
the regular course are strictly periodical, and
return always in the same order, though separat¬
ed at vast intervals. Notwithstanding the ex¬
uberance of his analytical resources, he was yet
obliged to omit the smaller quantities, and to adopt
certain admissible suppositions, in order to short¬
en the immensity of the calculation. But being
again recalled to the consideration of the subject,
he produced, four years afterwards, another dis¬
sertation, which surpassed all his former efforts,
and obtained the double prize of the Academy.
The great analyst new-modelled his investigation,
rendered the process much simpler and clearer,
pursued the approximations farther, and arrived
at more accurate results. He found that the mean
motions of Jupiter and Saturn are equally subject
782
PRELIMINARY DISSERTATIONS.
to a very slow increase or diminution5 wlncli al¬
ternates however in the lapse of 15,000 years.
But Euler was induced to push those researches
still farther, and gained the prizes proposed by
the Academy for the years 1754 and 1756, by his
theory of the inequalities in the Earth s motion,
caused by the planets. The three methods of
investigation that he proposed were all of them
quite different; and nothing seemed more asto¬
nishing than the facility with which his prolific
invention struck out new paths. He discovered
four small anomalies to result from their com¬
bined attractions, though it was scarcely pos¬
sible, for want of proper data, to assign the
precise measures of those aberrations. He ven¬
tured, however, to estimate the mean progres¬
sion of the aphelia at 12 seconds annually, and
the diminution of the obliquity of the ecliptic,
which some astronomers still doubted, at 49
seconds in a century. He found that the eccen¬
tricities of the aphelia of Jupiter and Saturn are
periodical, and complete their cycle in the space
of 30,000 years. By an inverted application of
the same principles, it was possible, by com¬
puting the co-efficients of the formulae from ac¬
tual observations, to determine the masses of
those planets which are not accompanied by sa¬
tellites. Euler hence found that Mars contains
rather less matter than the Earth, and Venus*
only about the half, hut which by a subsequent
calculation he nearly doubled. The process was
too much involved to secure entire confidence in
the results; and the rapidity and extent of his
calculations had led to occasional mistakes.
The same subject was in 1757 discussed
by Clairaut, in a clear and concise manner.
By comparing his formulae, with the accurate
observations of La Caille, he determined very
nearly the masses of the principal planets, and
showed that the greatest effect of their accumu¬
lated influence in deranging the Earth’s motion
can amount only to about a minute. His esti¬
mate of the attraction of Venus has been con¬
firmed by later and more elaborate calculations.
In 1749 D’Alembert investigated rigorously
the effects arising from the Moon’s attracting the
spheroidal prominence of the Earth. By the
transformation of his general expressions, he
found the Precession, or conical motion of the
terrestrial axis about the poles of the ecliptic, to
be 50 seconds annually, and its Nutation or alter¬
nate vibration on the same plane only 18 seconds
during the period of the revolution of the Lunar
Nodes. Comparing this quantity with observa¬
tion, he concluded that at the surface of the
Earth the attraction of the Sun is to that of the
Moon as 3 to 7, which makes the satellite to
have only the 70th part of the mass of our planet.
The powers of calculation were now turned
to the erratic class of the celestial bodies, so
long the objects of superstitious terror, but which
Newton had likewise subjected to the great law
of gravitation. While the planets revolve in
ellipses approaching to circles, and lying nearly
in the plane of the ecliptic, the comets describe
elliptical orbits with very different inclinations,
and so extremely elongated as to resemble pa¬
rabolas through a considerable part of their
course. Being very small, they are seen for a
short space only in the vicinity of the Sun, but
become quite invisible during their distant excur¬
sive journey beyond perhaps the boundaries of
our planetary system. The periodic time of a co¬
met, depending on the length of the transverse axis
of its ellipse, can seldom be determined with any
sort of accuracy. The few observations that
can be made in the transient interval of its ap¬
parition are scarcely sufficient to assign its mean
motion and the places of its nodes and perihe¬
lion. Newton, while he proposed the parabolic
theory as sufficiently correct in the visible por¬
tion of the cometary track, gave two elegant
constructions for discovering the elements of
the curve from three proximate observations.
Halley applied those principles to the laborious
computation of twenty-four remarkable comets.
But his attention was more especially fixed on
the nearest of them, which had been observed
in 1531, 1607, and 1682, and seemed to be the
same with one noticed by chroniclers in 1080,
1155, 1230, 1305, 1381, and 1456,1 and hence
1 This would seem to be the comet whose appearance after the capture of Constantinople by the Turks spread terror through
Christendom, and which pope Calixtus III. so devoutly exorcised in the same anathema with these dreaded infidels.
DISSERTATION FIFTH.
783
performing its revolutions in about 751 years; he
therefore ventured to predict its return about the
end of 1758 or the beginning of 1759. In arriv¬
ing at this conclusion he was equally fortunate
and circumspect; he found that the comet must
suffer great derangements in its passage through
our planetary system, from the attractions of
Jupiter and Saturn, which he endeavoured to
calculate, though with very doubtful success.
The time of the expected return approaching, ex¬
cited intense curiosity in the philosophical world;
and Clairaut was induced to apply his formulae
in the investigation of the progress of the comet,
which, after immense labour in calculation, as¬
sisted by several expert computers, he announced
at a public meeting of the Academy of Sciences
on the 14th of November 1758. He found that
the last revolution would be retarded about 618
days longer than the former, not reaching the
perihelion till the middle of April 1759. But
on revising his computation, he reduced that
term to the 4th of April, exceeding that of ob¬
servation by 12 days only, a discrepancy owing
probably to the influence of the remote planet
Uranus, which was not yet discovered. The comet
was first seen by a peasant in Saxony on Christ-
mas-day, but soon became the admiration of
Paris, and procured for Clairaut the enthusiasm
of popular applause. This remarkable erratic
star, though visible only for a few months, had
journeyed five years within the orbit of Saturn,
though it never stretched its excursion to twice
the distance of Uranus. It approached so near
to the Earth as would have disturbed her mo¬
tions, if its mass had not been extremely small.
The success and popularity of Clairaut drew
some peevish reflections from D’Alembert, whose
formulae, if he had taken the trouble to pursue
their application, would have led to similar re¬
sults. Euler, whose researches on Comets were
still more extensive and diversified, viewed this
triumph of ardent exertion with the calmness and
magnanimity of a sage. But Clairaut, eager to
complete a work in which he had gathered so
many laurels, next proceeded to calculate the dis¬
turbing influence of Jupiter and Saturn on the
place of the nodes of the comet of 1682 and 1759,
which has an inverted motion. Newton had
shown that the perturbations in the planetary
system always advance the perihelion and re¬
tract the nodes; but the case here was just re¬
versed, and the quantity of recession thence
determined agreed most exactly with observa¬
tion.
So gleamed the last efforts of a philosopher
who happily united the highest vigour of intel¬
lect with suavity of manners and elegance of
conversation, but whose days were shortened
by excessive labour, and the seductions of re¬
fined society, which incessantly courted and ca¬
ressed his presence. Clairaut died on the 17th
May 1765, at the age of 52, deeply regretted by
a very numerous circle of friends, and leaving
imperishable monuments of genius.1
A tribute of warm respect is paid to the memory of Clairaut by the celebrated but unfortunate Bailly, who thus elo-
quently pleads the cause of abstract science:—
“ Le portrait de M. Clairaut seroit celui du veritable Geometre. Un Gdometre est un homme qui entreprend de
trouver la vente ; et cette recherche est toujours penible, dans les sciences comme dans la morale. Profondeur de vue, ius-
tesse de jugement, imagination yive, voila les qualitds du Geometre : profondeur de vue, pour appercevoir toutes les con¬
sequences d’un principe, cette immense posterity d’un meme pere; justesse de jugement, pour distinguer entr’elles les
traits de famille, et pour remonter de ces consequences isolees au principe dont elles dependent. Mais "ce qui donne cette
profondeur, ce qui exerce ce jugement, c’est Pimagination; non celle qui se joue a la surface des choses, qui les anime de
ses couleurs, qui y rdpand I’e'clat, la vie, et le mouvement, mais une imagination qui agit au-dedans des corps, comme celle-ci
au-dehors. Elle se peint leur constitution intime; elle la change et la depouille a volonte'; elle fait, pour ainsi dire,
1 anatomie des choses, et ne leur laisse que les organes des effets qu’elle veut expliquer. L’une accumule pour embellir’
rautre divise pour connoitre. L’imagination, qui penetre ainsi la nature, vaut bien celle qui tente de la parer; moms’
bnllante que 1’enchanteresse qui nous amuse, elle a autant de puissance et plus de fide'litd. Quand I’imagination a tout
montre', les difficultes et les moyens, le Ge'ometre peut aller en avant; et s’il est parti d’un principe incontestable, qui
rende sa solution certaine, on lui.reconnoit un esprit sage; ce pnncipe le plus simple, offre-t-il la voie la plus courte, il a
1 elegance de son art; et enfin il en a le genie, s’il atteint une vcuite grande, utile, et long-tems senaree des vdrite's
connues!
“ Aucune de ces qualite's n’a manqud a M. Clairaut; les preuves sent de 1’histoire de la Geome'trie, les succes seuls
sont de notre ressort. L’Astronomie lui doit des progres difficiles ; nous le jugeons ici par ce qui inte'resse les hommes, et
sur ce qu’il a fait d’utile. La thdorie de la lune rested imparfaite dans les mains de Newton, le cours des cometes calculd,
leur retour predit, en rendant compte des causes qui le retardent ou qui le precipitent; voila ce qui restoit i faire depuis
Newton, depuis Halley ; et voila ce que M. Clairaut a fait. Cela dtoit difficile, puisque deux grands hommes y ont etd
arretes; cela dtoit utile, pareeque la connoissance des mouvemens de la lune amenera la perfection de la ge'ographie et de la
navigation, pareeque la prediction du retour des cometes caractdrisera notre siecle et fera sa gloire. Le principal mdrite
784
PRELIMINARY DISSERTATIONS.
But the Theory of Comets still remained incom¬
plete. Those excursive bodies, in traversing our
system, often suffer such derangement from the
influence of the proximate planets, that the most
select observations are insufficient to determine
with any sort of precision their elliptical orbits.
The famous comet of 1759 was calculated by Eu¬
ler and Lexell to perform its revolution in a space
between 449 and 519 years, while Pingre assigned
it the period of 1231 years. In some cases the
observations have indicated an hyperbolic orbit.
Conti, following the method of Gauss, found
the comet of 1811 to revolve in 3056*3 years;
but by a second computation he reduced the
time to 2301 years. The profound and expe¬
rienced calculator Bessel lately gave the comet
of 1807 a period of 1953*2 years, which he next
brought down to 1483*3. The attraction how¬
ever of the Earth would increase this to 1713*5
years, while the influence of Jupiter would re¬
duce it again to 1543*1 years. Although the
process of calculation he now greatly improved,
the return of a new comet cannot he safely pre¬
dicted. Our expectations can acquire confidence
only from a comparison with former appear¬
ances.
Though the comets suffer such derangement
from the action of the larger planets, they have
no sensible influence on our system. They
must therefore be extremely small, consisting
of a dark nucleus, invested with a cloudy or
hazy excrescence, and generally provided with
very long sweeping tails. They have never
disturbed our tides ; though, haying sometimes
approached within the third part of the dis¬
tance of the Moon, they would consequently
with the same mass exert twenty-seven times
greater deranging force. But their passage was
then so rapid as not to allow the accumulation
of impulse required to heave the wide expanse
of ocean.
Comets are distinguished by the elements of
their orbits, derived only from observations
made near the perihelion. Newton gave an
elegant method of discovering those paths, by a
geometrical construction grounded on the para¬
bolic theory, and embracing three distinct ob¬
servations. But this solution is liable to much
uncertainty in its application, and Boscovich
has shown how in most cases it merges in a
porismatic or indefinite result. Mathematicians
have therefore employed the resources of ana¬
lysis in the resolution of this problem. Euler,
besides the three consecutive observations, adopt¬
ed a fourth one more remote, and thus obtained
an accuratebut very tedious and involved process.
Lambert derived a different mode of solution from
some general properties which he discovered of the
Conic Sections in 1761. He employed calculation
combined with a graphical process, and sought
to abridge the labour, by help of a table of the
descents of comets, or the motions which they
would perform if their parabolic paths collapsed
into straight lines. Thomas Simpson, the only
person in our island who at this time appeared
to emulate the Continental mathematicians, like-
wise produced ingenious disquisitions on the
Comets, and framed similar tables. Hennert,
Tempelhoff, and Sejour, afterwards pursued the
same subject, which has since been discussed
with great ability by Lagrange, Laplace, and
Legendre. Other methods for discovering the
orbits of comets have been more recently pro¬
posed by Delambre, Olbers, and Gauss; the last
of which may be considered as the most elegant
and complete. But all these analytical modes
of solution are still very tedious and compli¬
cated; insomuch that the humbler procedure
by the way of Trial and Error, or what is called
False Position, is found in practice to be on the
whole the shortest and most satisfactory.1
While the sublimer geometry thus gradually
disclosed the various recondite anomalies which
de M. Clairaut fut le talent des applications : malgre son gdnie, il n’etoit point rebutd des details; il pensoit qu’une veritd
de pratique etoit preferable a celles qui restent ensevelies dans vingt pages d’analyse; aussi n’a-t-il fait que des choses utiles.
Son nom a etd connu, porte partout, et sera repe'te dans les ages. Si nous avons ose le louer, c’est que I’Astronomie
lui doit de la reconnoissance, c’est que nous sommes au moment oil la postdritd commence pour lui. La veritd peut dlever
une voix tranche et libre, et nous ne sommes que son organe.” (Hisioire de I’Astronomie Moderne, tome iii. pp. 197, 198.)
1 The most accessible work that has recently appeared on this very difficult subject is the Essay on Comets, which gained
the first of Dr Fellowes’ Prizes in the University of Edinburgh, and which reflects such credit on its youthful author,
David Milne, Esq. advocate.
DISSERTATION FIFTH.
785
affect the planetary motions, and yet maintain
the balanced harmony of the universe, a genius
of the first order arose, and placed himself at
once on the summit beside the chief mathema¬
ticians of the age. In 1759 Lagrange, when
only 23 years old, gave a new extension to the
Integral Calculus, under a form which has ob¬
tained the appellation of the Calculus of Varia¬
tions, and applied this with singular address to
the rigorous solution of the very difficult pro¬
blems of the propagation of sound, and the
vibration of a musical chord. His early pro¬
gress was hailed by Euler, and encouraged by
D’Alembert. No mathematician has ever dis¬
played a completer command of the Calculus
than Lagrange, who rivals Euler himself in
clearness, elegance, and fertility of invention,
and eminently surpasses that great master of
analysis in the justness and expansion of his phi¬
losophical views.
The next effort of Lagrange obtained him the
prize offered by the Academy of Sciences at
Paris in 1764, for his Discourse on the Libra-
tion of the Moon, in which he most satisfac¬
torily explained, from the theory of Attraction,
the cause of the Moon’s presenting always near¬
ly the same face towards the Earth. He arrived
directly at the same general equations as D’Alem¬
bert, by a happy combination of the dynamical
principle of that philosopher with the property
of virtual velocities, which was the germ of his
capital work on Analytical Mechanics. This
subject he again resumed in 1780, and discussed
it in the fullest and most accurate manner,
having succeeded *in completing the integration
of the chief equations.
The theory of Jupiter’s Satellites is not only
an object interesting in speculative science, but
of great importance in the practice of astrono¬
mical observation for finding the longitude.
Bailly, applying merely the formulae of Clairaut,
obtained an imperfect solution of their periodic
motions. In 1766 the genius of Lagrange em¬
braced this subject in its full extent, by intro¬
ducing into his equations not only the attractive
force of the Sun, but the mutual attractions of
the Satellites themselves. He neglected no term
which might sensibly affect the results, and ad¬
vanced with caution and address by successive
DISS. V.
approximations. His investigation was a model
of analytical research; yet, though capable of
extensive application, it did not descend into all
the practical details.
The Lunar Theory still presented difficulties
which it required the utmost efforts of genius
to abridge and partially remove. In 1768
D’Alembert simplified the evolution of the dis¬
turbing forces, by projecting orthographically the
moon’s orbit on the plane of the ecliptic. Euler,
in conjunction with his son Albert, now gave
the completest solution of the general problem
that had yet appeared; but having discovered
no indication of a secular equation affecting the
Lunar motions, they were inclined to doubt its
existence. This arduous discussion was repeat¬
ed in 1772, on which occasion Lagrange shared
the prize with the Eulers. Two years after¬
wards he resumed the subject, and closely exa¬
mined the different conditions annexed to the pro¬
gramme. There are five elements of a planet’s
motion liable to the influence of Disturbing
Forces: 1. The Great Axis of the primary ellipse;
2. The Eccentricity of the orbit; 3. The Incli¬
nation of its plane; 4. The position of its Nodes;
and, 5. The direction of its line of Apsides.
In 1776 Lagrange demonstrated that the great
axis, on which depends the period of revolution,
has no term involving the lapse of time, and
therefore cannot be affected by any Secular Equa¬
tions, which constantly increase or diminish.
But with regard to the mean motions of Jupiter
and Saturn, Lagrange and Euler came to oppo¬
site conclusions, the one exhibiting a continual
acceleration, and the other a like retardation.
Laplace, who has attained still higher cele¬
brity, now appeared on the scene. Displaying
the same faculty of invention, he possessed
nearly equal skill in the management of the
Calculus, without reaching, however, the clear¬
ness, simplicity, and elegance of his illustrious
rival. But he ranged over a wider field of dis¬
covery, and exerted greater and more persever¬
ing industry, and pressed forward with a loftier
feeling of ambition.
In 1773 Laplace, following the steps of La¬
grange, adopted a new mode of investigation,
and pushed his calculations farther. Instructed
by the successive advances of his predecessor, he
5 a
786
PRELIMINARY DISSERTATIONS.
proved in 1775 that the mean motions of Jupiter
and Saturn have no secular equations, hut per¬
form all their changes within certain long periods,
which hence reconciles the discordant conclu¬
sions of Euler and Lagrange. Having found
that the variation of eccentricity of Jupiter’s orbit
must cause a corresponding alteration in the mo¬
tion of the Satellites, Laplace transferred the
same idea to the perturbations of our Moon, and
thus discovered the true theory of her secular
equation, or rather of that vast cycle in which
the lunar revolutions are alternately accelerated
and retarded. This very slow but gradual
diminution of the moon’s periodic motion, which
the intermediate observations of the Arabian
Astronomers, between Hipparchus and Bradley,
have incontestibly established, was at one time
referred to the resistance from an ethereal fluid
imagined to occupy the celestial spaces. La¬
place at first conceived that the retardation might
be explained on the hypothesis of a progressive
transmission of the power of Attraction, and com¬
puted that it would require 8000 times the cele¬
rity of Light, which travels 200,000 miles in
a second, to produce this effect. But his sub¬
sequent inquiries having shown that Gravity
must dart its influence more than 50 million
times faster than Light, we may therefore safely
consider it as quite instantaneous. This conclu¬
sion is highly important in a philosophical view,
since it sets for ever at rest the various specula¬
tive attempts to explain the cause of Attraction
by the agency of certain mechanical intermedia,
and demonstrates it to he a primordial and ul¬
timate principle ordained by the Wisdom of the
Supreme Architect.1 * * * *
In the meanwhile Lagrange had in successive
dissertations investigated the secular variations
of the planets by a new and direct process, which
he conducted with incomparable address and
elegance. Nor did he confine his researches
merely to theory, but applied the formulce to the
motions of the five planets then known. In a
subsequent investigation he most skilfully se¬
parated the terms of the equation which exhibit
the secular deviations, from those which repre¬
sent the periodical changes.
The soaring rivals appear alternately to sur¬
pass each other. Laplace, continuing his re¬
searches, at last discovered, that the secular
equation of the Moon affecting her mean motion
and that of her perigee and of her nodes in the
ratio of 4, 12, and 3, is produced by the slow
variation of the solar attraction occasioned by
the changing eccentricity of the Earth’s orbit
resulting from the influence of the larger planets,
though they cannot alter the great axis which
determines the mean periodic revolution. La¬
grange then showed that the same results were
deducible from his general formulce. In 1785
Laplace resumed his investigation of the motions
of Jupiter and Saturn; and suspecting that Euler
and Lagrange had not carried their approxima¬
tion sufficiently far, he pushed his calculations
from the second to the fourth powers of the ec¬
centricities of their orbits, and proved that those
planets can have no secular equations. But,
having remarked that their mean periods are
commensurable and very nearly as 2 to 5, he
found their reciprocal acceleration and retarda¬
tion to follow the same ratio. The cycle began
in 1560, and comprehends 929 years; so that at
the epoch of 1750 Saturn had his period short¬
ened 48’ 44", while that of Jupiter was lengthen¬
ed by 19' 28". In 1788 he discovered two curi¬
ous laws that connect the periods of Jupiter’s
Satellites, and gave a complete theory of their
motions, which served as the basis of Delambre’s
excellent Tables.
After an interval ofseveral years, duringwhich
Lagrange had totally suspended his mathemati¬
cal studies, he returned to his early pursuits with
all the freshness of youthful invention, and all
the vigour of matured and improved intellect. In
1808 he gave a most general solution of the pro¬
blem of Disturbing Forces, and by a wonderful
effort of sagacity he reduced his equations into a
form of the utmost simplicity and elegance.8
1 It is rather singular that Laplace should on several occasions betray a disposition towards materialism, while his inves¬
tigations point evidently to an opposite inference.
* Since all observations are liable to incidental inaccuracies, it requires great address to balance the opposite errors. The
ordinary way is to take the arithmetical mean; but this mode confounds equally the remote and the approximate indica¬
tions. Cotes, in his Estimate of the Errors of Observation, proposed an ingenious and more accurate mode of investigation,
DISSERTATION FIFTH.
787
The eighteenth century was equally distin¬
guished by the progress of Practical Astronomy.
Observatories were greatly multiplied and wide¬
ly dispersed over the surface of the globe, the
art of making observations was brought to high¬
er perfection, and instruments of more delicate
construction were successively introduced. Be¬
sides the great problems of the figure of the
Earth and the nutation of her axis, we may enu¬
merate four capital improvements: The mea¬
sure of celestial refraction—the determination of
the parallaxes, and consequently the mean dis¬
tances of the Moon and Sun—the discovery of
new planets and satellites—and the enlarged
survey of the heavens, comprising the groups
and various modifications of the fixed stars.
1. Celestial Refraction. A ray of light passing
obliquely from a rarer into a denser medium, is
bent or refracted towards the perpendicular.
The light emitted by the heavenly bodies, when
it enters our atmosphere and descends to the
surface through a succession of condensing strata,
must evidently describe an incurved path ; and
the particles which reach the eye and produce
vision, pursuing the direction of the terminal
tangent, will give to a star an apparent eleva¬
tion. The portion of the trajectory traced in ap¬
proaching the surface of the Earth may be con¬
sidered as an arc of a circle having its radius
about six times greater. The quantity of refrac¬
tion is hence nearly proportional to the tangent
of the altitude.
Hawksbee had in 1710 found by a nice ex¬
periment, that the refractive power of air com¬
pared with that of water is in the ratio of its
density; and this law was ascertained by Biot
and Arago about a century afterwards to be gene¬
ral in our atmosphere. Hence refraction of that
medium increased with the elevation of the baro¬
meter or the depression of the thermometer.
The effect of cold was early remarked by the
Dutch Arctic voyagers; but Bouguer first ac¬
curately observed the diminished agency of at¬
tenuated air during his sojourn on the summits
of the Andes. Yet without demonstration Brad¬
ley gave a simple rule for computing the celes¬
tial refraction, and Mayer adopted another near¬
ly similar. Thomas Simpson, in a very ingeni¬
ous dissertation, derived a formula which is sub¬
stantially the same. The subject of refraction
has likewise been discussed by Lambert, Kramp,
Fontana, and more recently by Laplace, Gauss,
Bessel, Young, and Ivory. The formula of La¬
place is complicated and inelegant, while Ivory’s
method seems clear and simple.
2. The Lunar and Solar Parallaxes. The
nearer celestial bodies are seen from the surface
of the Earth in a position somewhat different
than if viewed from the centre. This deviation,
termed parallax^ is obviously greatest at the ho¬
rizon, and diminishes constantly in approaching
to the zenith. To ascertain parallax with any
precision, it is therefore required to institute
observations at distant stations. It was chiefly
for this purpose that La Caille selected the Cape
of Good Hope, where he determined the mean
parallax of the moon to be 57' 39". But the
parallax of the sun, being so small a quantity,
is much more difficult to find. Kepler had taken
it for a minute, Halley reckoned it at 25", but
subsequent astronomers had generally reduced
the estimate to 10 seconds. To determine this
element with accuracy, Halley proposed a very
ingenious method from the next transit of Ve¬
nus, by measuring the acceleration and retar¬
dation of the time of her passage over the disc
of the sun as viewed from remote points on
the surface of the globe. He could not expect
his life k) be prolonged till that event, but he
warmly exhorted his successors to prepare them-
which, reduced to its simplest form, consisted in projecting the several data on a plane, and assigning their common centre
of gravity for the true result. Euler disposed the observations into conditional equations with indeterminate co-efficients,
which he traced out by successive eliminations. Mayer adopted the same plan, and employed it most extensively in the
construction of his valuableTables. But this procedure being very laborious, Legendre proposed to abridge it by the method
of the least squares, which had likewise occurred to Gauss, being generally used by him in the reduction of observations. It
was a fine application of the Doctrine of Chances. Various algebraical investigations of the principle have been given;
but they are commonly very intricate and abstruse.
Mathematicians, in threading the labyrinths of analysis, seem to have overlooked a most simple and luminous demon¬
stration furnished by the Ancient Geometry. From an elegant proposition of the Loci Plani, it follows as a corollary, that
the sum of the squares of the distances of any number of points from their centre of gravity is a minimum; which therefore
merges in the solution of Cotes.
788
PRELIMINARY DISSERTATIONS.
selves for observing it on the 5th of June 1761.
Astronomers were accordingly dispatched by the
several maritime powers of Europe to all the
stations that were considered as the most eligi¬
ble and accessible. Owing to various accidents,
however, the results did not answer the expecta¬
tions raised. The stations had not been always
the best chosen; some of the most expert observ¬
ers did not reach their proper destination, others
were obstructed in their operations by the state
of the weather, and many difficulties generally
occurred which had not been provided for.
From a comparison of the collected observa¬
tions, Pingre deduced a parallax of 10^", while
Short made it only 8|". Such a discrepancy was
mortifying, and astronomers looked forward with
impatience to the succeeding transit of Venus,
which was fortunately to happen within the space
of eight years, though such an occurrence would
not take place again till the 8th of December
1874. In the meanwhile Dr M. Stewart reviv¬
ed an idea of Machin, who, from a rude com¬
putation grounded on the motion of the Moon’s
Nodes, estimated the Solar parallax at 8". He
preferred however the change of the apogee, or
of the direction of the principal axis, which is af¬
fected in some degree by the sun’s distance. By
the application of the Greek Geometry alone,
Stewart had with profound ingenuity achieved
the solution of a problem which so long baffled
the address of the great masters of the modern
calculus ; but in pursuing his deductions, the
passion for purity and elegance of demon¬
stration led him to hazard so many simplifica¬
tions, as to render the conclusion, amidst a
balance of errors, very doubtful and precarious.
He reduced the parallax to 6'9", which from its
smallness excited considerable surprise.
The uncertainty regarding the sun’s real
distance was finally removed by the skilful
and numerous observations of the Transit of the
3d of June 1769. The several results differed
scarcely the quarter of a second, and their con¬
currence fixed the parallax at 8‘6". This like¬
wise agrees with the theoretical calculations of
Laplace from the Lunar anomalies. But Bessel,
having with immense labour combined and care¬
fully recomputed the original observations, has
recently detected a small correction, which makes
the parallax to he only 8*575", and consequent¬
ly the mean distance of the sun 95,158,440
English miles.
3. Discovery of New Planets and Satellites. It
was an inveterate opinion, derived from the
ancient Pythagoreans, that the number of the
great celestial bodies must of necessity he six,
the first perfect number, or one which contains
all its subdivisions. When Galileo directed his
tube to the heavens and detected some of the
satellites of Jupiter, this notion retarded the
assent of the learned to his discovery; hut after
Saturn was found to he accompanied likewise
by satellites, speculative philosophers sought to
extend the catalogue of revolving stars to 28,
the next perfect number. In this expectation,
however, they were disappointed, and the Solar
System received no further accession for the
space of a century. The discovery of a New
Planet was reserved for our own times.
Herschel, a musician residing at Bath, though
a native of Hanover, which he had left in early
youth, devoted his leisure to the construction
and improvement of reflecting telescopes, Avith
which he continued ardently to smwey the
heaArens. His zeal and assiduity had already
drawn the notice of astronomers, when he an¬
nounced to Dr Maskelyne, that, on the night of
the 13th of March 1781, he observed a shifting
star, which from its smallness he judged to he a
Comet, though it was distinguished neither by a
nebulosity nor a tail. The motion of the star,
howeA^er, Avas so slow as to require distant ob¬
servations to ascertain its path. It was for
several months presumed to he a Comet; hut the
hypothesis of a parabolic orbit led to Arery dis¬
cordant results. The president Saron, an expert
and obliging calculator, was the first who con¬
ceived it to he a Planet, having inferred from the
Few observations communicated to him, that it
described a circle with a radius of about twelve
times the mean distance of the Earth from the
Sun. Lexell removed all doubt, and before
the close of the year he computed the elements
of the New Planet with considerable accuracy,
making the great axis of its orbit 19 times greater
than that of the earth, and the period of its re¬
volution 84 years. Bradley, mistaking it for a
fixed star, had observed it on the 3d December
DISSERTATION FIFTH.
789
1753; and it was again seen by Mayer on the
23d September 1756.
Herschel proposed, out of gratitude to las
Royal Patron, to call the planet he had found
by the barbarous appellation of Georgium Sidus ;
but the classical name of Uranus, which Bode
afterwards applied, is almost universally adopted.
Animated by this happy omen, he prosecuted his
astronomical observations with unwearied zeal
and ardour, and continued during the remainder
of a long life to enrich science with a succes¬
sion of splendid discoveries. But Herschel also
detected the satellites that accompany his planet,
amounting to six, which revolve in a plane
nearly perpendicular to its orbit, and contrary
to the order of the signs. Both these primary and
secondary bodies obey, in the relation of their
motions and distances, the great law of Kepler.
The same conformity obtains in the revolutions
of the satellites of Saturn, which he increased
to seven; and thus every step in the progress of
astronomy gives additional solidity to the grand
system of attraction.
Some German philosophers, indulging their
curious fancy, have traced among the distances
of the planets an analogy, which, though not
strictly accurate, yet approximates so near the
truth, that if not really founded in nature, it may
at least assist the memory. Kepler, whose
ardent imagination inflamed all his speculations,
believed that the harmony of our system wanted
a planet between Mars and Jupiter. A similar
notion was entertained by the ingenious Lam¬
bert, who further supposed it might be dark and
invisible. Reckoning from Mercury, the first of
planets, and assuming as the unit of measures
its interval from the sun, the intervals of the
rest will be expressed by the binary progres¬
sion 2, 4, 8, 16, &c.; and consequently the
distances of the series of planets from the sun
may be represented by the numbers 1, 2,
3, 5, 9, 17, 33, 65, &c. While 3 denotes the
distance of the Earth, and 17 and 33 indicate
the distances of Jupiter and Saturn, the remote
Uranus has come to occupy the place marked
by 65. But a planet at the distance 9, between
5 and 17, the distances of Mars and Jupiter, was
still wanting to complete the regular sequence.
Bode slightly modified these proportions, and
attained greater accuracy, at some expense,
however, of simplicity. Taking the number 4 to
express the interval of Mercury, he multiplied
the terms of the binary progression by 3. The
distances of the planets from the Sun are hence
denoted by the series 4, 7, 10, 16, 28, 52, 100,
196, &c. which numbers are convertible into
English miles by multiplying by 9^ millions.
The dark or deficient planet, corresponding to
28 or the distance of 266 millions of miles, is
now supplied by the discovery of four very small
stars, which have been fancifully conjectured
to be only fragments dissevered from the prin¬
cipal, while other portions, still unobserved,
are whirling through space. The detection of
those singular planets distinguishes the com¬
mencement of the nineteenth century. Piazzi
discovered Ceres at Palermo on the 1st of
January T801, Olbers at Bremen found Pallas
on the 28th of March 1802, and his countryman
Harding added Juno on the 2d of September 1804,
and Vesta on the 29th of March 1807. These
asteroides, as they have been called by Herschel,
differ from other planets not only by their di¬
minutive size, but by the remarkable inclination
of their orbits to the plane of the ecliptic, which,
however, they intersect nearly in the same nodes.
This wonderful extension of the Solar System
was chiefly due to the zeal and industry of the
German and other confederated Astronomers,
who, at the instance of the spirited Baron Zach,
had divided the heavens into different sections,
and occupied themseRes in surveying their
several allotments. The catalogue of fixed
stars was thus prodigiously augmented, and
many peculiarities in their character and con¬
figuration detected. In the meanwhile Herschel,
with the superior aid of his powerful reflecting
telescopes, observed the numerous clusters of
nebulosities, and distinguished many of the
changing and double stars, which, though suns
of other systems, yet appear connected, and may
probably circulate about their common centre
of gravity. Assuming that the instrument he
used could enable him to penetrate 497 times
farther than Sirius, he reckoned 116,000 stars to
pass in a quarter of an hour over the field of
view, which subtended an angle of only 15'. If
we compute from such a narrow zone, the whole
790
PRELIMINARY DISSERTATIONS.
celestial vault must display, within the range of
telescopic vision, the stupendous number of more
than five billions of fixed stars. Imagination is
bewildered in the immensity of such prospects.
But a sober retrospect of the progress of astro¬
nomy would aid our conception of the structure
and harmonious adjustment of the universe.
“ To generate a circular description, it is
requisite that the body should have the precise
celerity due to a fall through half that radius.
But, projected with inferior celerity, it would,
about the same axis, trace elliptical orbits more
or less compressed; the foci mutually retiring
towards the extremities, while the conjugate
diameter contracts. When the primary im¬
pulsion becomes extinct, the elongated ellipse
merges in a straight line. On the other hand,
if the projectile motion should exceed the limit
of circular velocity, a new series of curves will
arise. But when the acceleration is directly as
the distance, on passing the limit of celerity, the
foci will first unite in the centre, and the axis
suddenly turning at right angles, the foci will
now gradually dispart in this transverse position.
As the velocity of impulsion is successively aug¬
mented, the ellipse will assume all the degrees
of oblateness, till it finally vanishes in two pa¬
rallel lines.
C{ If the centripetal force be inversely as the
square of the distance, the moment the primary
impulsion transcends the limit due to a circular
trajectory, the orbit would suddenly change into
an equilateral hyperbola; the farther focus,
which had come to coalesce with the attractive
one, now flying to the opposite side beyond the
diameter. When the celerity of projection re¬
ceives a farther increase, the incurvation at the
vertex will he proportionally diminished. With
an extreme impulsion, the body would shoot off
in a straight line perpendicular to the axis.
“ It thus appears, that a circular revolution,
which the ancients so fondly contemplated as the
perfection of the celestial movements, is incom¬
patible with the stability of the universe. The
most absolute precision of impulse would have
been necessary, and the very slightest subsequent
addition of celerity, from the incidental influ¬
ence of those disturbing forces which are inces¬
santly in operation, would at once have trans¬
formed the circle into a hyperbola, and have
carried the planet away for ever into the bound¬
less expanse of heaven. In viewing the grand
phenomena of nature, our admiration is drawn
to those conservatory principles which, in short¬
er or longer periods, correct every occasional de¬
viation from the general balance of the system.
“ It is curious, however, to remark how very
nearly the planetary orbits approximate to cir¬
cles. In that of our earth, the two axes differ
only by the 7086th part. In the trajectory of
Mars, this difference amounts to the 231st part.
It was accordingly the greater eccentricity of
that orbit which led Kepler to detect its ellipti¬
cal form. The group of small kindred planets
lately discovered revolve in curves still more
elongated, the diameters of those of Juno and
Pallas being nearly in the ratio of 30 to 29.
These singular bodies might seem to rank be¬
tween the ordinary planets and the comets,
which wander in ellipses of extreme elongation,
scarcely distinguished from parabolas, during a
great part of their visible track. In another
circumstance, too, the analogy obtains; for
while the larger planets deviate not more than
2 or 3 degrees from the plane of the ecliptic,
Pallas crosses it at an angle of 35°, and the
paths of the comets have every possible inclina¬
tion. It remains to he discovered, whether di¬
versified bodies, travelling in the celestial spaces,
may not fill up more completely that prolonged
gradation of existence, which appears so con¬
spicuous in other parts of nature. Supposing
the projection of the planets to he the result of
some more general law, those which had an ex¬
cess of impulsion would totally escape our range
of observation, being swept away in hyperbolas
into boundless space, there perhaps to form
other stellar systems.”1
The ingenious Lambert produced some curi¬
ous speculations respecting the celestial bodies.
He presumed that the various planetary systems
are all connected, and revolve about a common
centre, which Galileo had conjectured to he si¬
tuate in Orion or Sirius. The planets, therefore,
1 Elements of Natural Philosophy, pp. 123-125.
DISSERTATION FIFTH.
791
do not strictly describe ellipses, but a series of
convoluted epicycloids. He showed that comets,
in passing the nearest planets, might have their
orbits changed into parabolas or even hyperbo¬
las, and hence journeying from system to sys¬
tem, would perform the tour of the universe.
Those erratic bodies he peopled with a race of
contemplative astronomers, who, enjoying such
peculiar advantages, could survey the whole ex¬
tent of the starry frame.
Lambert remarks, that, between the 16th and
17th centuries of our era, we have been visit¬
ed by 40 comets that have not appeared again.
These must, from their brilliancy, have reached
the earth’s orbit, and perhaps come within the
verge of Venus and Mercury. But the very
elongated cometary paths might descend in va¬
rious directions without interfering with the
planets. Calculating on the principle of chances,
he found that no fewer than 500,000 comets
might have the aphelia of their ellipses situate
in the orbit of Saturn. But if we extend this
computation to the orbit of Uranus, we may
reckon up two millions of comets, as probably the
number of those erratic attendants of our system.
Mr Milne carries the estimate still higher. As¬
suming a thousand years for the average period
of the revolutions of the comets, it would re¬
quire to multiply by ten the 140 which have
been observed within the earth’s orbit during
the last hundred years, giving 1400 for the
whole of such near visitors. But Uranus being
twenty times more distant, the product of the cube
of this, or 8000 into 1400, exhibits 11,200,000
as the approximate number of all the comets
which range within the known extent of our
system.
The periodical change of the inclination of
the ecliptic is at last established, though the
quantity of variation and the length of its cycle
have not been absolutely determined. Schubert,
in his treatise of Practical Astronomy, makes it
to fluctuate between 18° and 29°, altering in the
space of 65,000 years from 27° 45’ to 20° 43'; the
maximum having occurred at the remote period
of 36,300 years. But Delambre and Piazzi,
whose judgment and scientific attainments rank
much higher, have reduced this aberration with¬
in the moderate limits of 1° 20'. The greater
obliquity of this ecliptic in ancient times, by
elevating the sun more in summer, and depress¬
ing him in winter, must have proportionally in¬
creased the diversity of the seasons. But still
the mean temperature of the earth has conti¬
nued for ages exactly the same; for the momen¬
tum of rotation at first impressed remaining ne¬
cessarily invariable, the smallest rise of heat,
expanding the revolving mass, must have retard¬
ed its motion, and consequently lengthened
somewhat the day. Any decrease of heat, on
the contrary, would accelerate the terrestrial ro¬
tation. Now, the length of day has certainly
not altered a single second of time since Hip¬
parchus observed eclipses 3000 years ago; and
it therefore follows, that during this long period
the mean temperature of the earth has not va¬
ried the fraction of a degree. The constant ac¬
cession of heat from the sun must hence be con¬
sumed by some process yet unexplored. Unless
this heat were again to resume the form of light,
it could not be darted from the upper atmo¬
sphere through the boundless void. Since the
waters of the ocean are colder in proportion to
their depth, might we not suppose the bottom
to be frozen, and all the surplus heat to be ab¬
sorbed in melting the subaqueous ice ?
Astronomical considerations likewise eluci¬
date the internal structure of our globe. The
mean density of the mass is about double that of
its exterior crust. But if the general materials
were the same, and the law of compression sub¬
sisted in any degree, the resulting condensation
would be inconceivably greater. Air compress¬
ed into the fiftieth part of its volume was lately
found in France to have its elasticity fifty times
augmented; and had it continued to contract at
this rate, it would from its own incumbent weight
have acquired the density of water at the depth
of 34 miles. But water itself would have its
density doubled at the depth of 93 miles, and
even attain the density of quicksilver at a depth
of 362 miles. In descending therefore towards
the centre, through the space of about 4000 miles,
the condensation of ordinary materials would
surpass the utmost powers of conception. “ It
seems therefore to follow conclusively, that our
planet must have a very widely cavernous struc¬
ture, and that we tread on a crust or shell.
792
preliminary dissertations.
whose thickness bears a very small proportion
to the diameter of its sphere. But since an ab¬
solute void is inadmissible, the vast subterra¬
nean cavity must he filled with some very diffu¬
sive medium, of astonishing elasticity or inter¬
nal repulsion among its molecules. The only
fluid we know possessing that character is Light.
itself, which when embodied constitutes Ele¬
mental Heat or Fire. The great concavity may
thus be filled with the purest ethereal essence,—
Light in its most concentrated state, shining
with intense refulgence and overpoivering splen¬
dour.” 1
It was the firm opinion of the ancients that
our atmosphere rises as high as the Moon, the
whole space below being doomed to change, decay,
and mortality; and this notion still tinctures the
language of poetry. But Kepler first reduced
the extent of atmosphere within moderate limits.
Astronomers having observed that twilight com¬
monly closes after the sun has sunk 18 degiees
below the horizon, it was hence easy to com¬
pute that the highest portion of air which from
the west reflects the departing ray must have an
altitude of about 44 miles. This conclusion,
however, seems invalidated by the lemaik of
Lambert, that twilight does not absolutely cease,
but is succeeded during the night by a series of
decreasing crepuscles, formed by a double, a
triple, or even a quadruple reflection. These
secondary lights may therefore be produced by
the repeated gleaming from the sky at much
lower elevations.
A wider limitation of the atmosphere is de¬
rived from a rigid principle. It is evident that
the particles of air, as they expand from the
axis of rotation, will augment their centrifugal
tendencies, while their attraction to the centre
will diminish in a duplicate ratio. At a certain
distance, therefore, those antagonist forces will
produce a mutual equilibrium. This balance
must occur in the equatorial region at the height
of 6-6 semidiameters, or about 26,000 miles,
when the centrifugal force is increased, and the
power of gravitation is reduced to about -i--
The late Dr Wollaston arrived at nearly a si¬
milar conclusion, from an hypothesis respecting
the ultimate molecules of the atmosphere. But
a different consideration will bring us within
much narrower limits. If we assume the de¬
pression of the absolute zero to be 750 centesi¬
mal degrees, and adopt the formula already
stated for the relation of the density and tem¬
perature of air, it will follow that the tenuity
of the highest stratum of the atmosphere cannot
exceed 50 X 750 or 37,500 times, which corre¬
sponds to an altitude of about 51’|- miles. This
boundary nearly coincides with the approxima¬
tion of Kepler, and likewise agrees sufficiently
with the estimated range of the Aurora Borealis.
It thus appears from concurring probabilities,
that our atmosphere extends not above 50 miles,
the higher regions perhaps being occupied by
hydrogen gas transfused with phosphorescent
matter.
The perfection of astronomical instruments
has afforded the prospect of being able to deter¬
mine the Annual Parallax, and consequently the
distance of the fixed stars; but the quantity of
deviation is so small as to have hitherto eluded
the closest observation. It cannot amount to a
single second in the most conspicuous and pio-
bably the nearest of the stars. These luminous
bodies must therefore be more distant at least
two hundred thousand times than the measuie of
the diameter of the earth. The light emitted
from such neighbouring suns, though it flies
with enormous rapidity, must yet travel moie
than six thousand years before it approaches the
confines of our system.
But scattered over the immensity of space,
there may exist bodies which, by their magni¬
tude and predominant attraction, retain or re¬
call the rays of light, and are lost in solitude
and dai'kness. Had the celerity of the luminous
particles not exceeded four hundred miles in a
second, we should never have enjoyed the cheer¬
ing beams of the Sun. They would have been
arrested in their journey, and drawn back to
their source, before they reached the orbit of
Mercury. But a star similar to our Sun, and
having a diameter 63 times greater, would en¬
tirely overpower the impetus of light.
1 Elements of Natural Philosojphy, pp- 449-453.
DISSERTATION FIFTH.
793
Many of the smaller stars are found to have
proper motions, some of them to an extent of
several degrees. Mayer attempted to class the
shifting stars according to their places in the
heavens, and remarked that, while those situate
in two opposite quarters appeared nearly sta¬
tionary, such as had a lateral position varied the
most. He therefore inferred that our Sun and
the whole train of his attendants are carried
forward in the line joining those opposite points.
Herschel seized this ingenious idea, and com¬
bining his own observations, he concluded that
the translation of the planetary system is di¬
rected to the constellation of Hercules. But
the critical examination of Bessel has proved
that no such regular transfer would reconcile
the various discrepancies of the shifting stars.
The Double and Multiple Stars have lately
engaged the attention of observers. Their ca¬
talogue has been prodigiously augmented by the
ardour of South and the younger Herschel, and
by the unwearied assiduity of Struve at Dorpat,
and of Inghirami at Florence. The Double
Stars assume every hue, but generally the con-
trasted or complementary colours; a circum¬
stance which seems to betray the influence of
ocular deception. Their proper motions result
probably from a circulation around their com¬
mon centre of gravity. The Multiple Stars may
possibly derive their peculiar aberrations in
certain cases from the revolution about huge
invisible Suns. All these mutable Stars are
extremely remote, descending so low as the
twentieth degree of magnitude, and can there¬
fore be distinguished only by the penetration of
the most powerful telescopes. Imagination is
utterly bewildered by the shadowy visions which
flicker along the horizon of Illimitable Space.
But each successive observation reveals more
clearly the extension of that exquisite harmony
which the great law of attraction maintains
through the countless systems of Worlds.
END OE VOLUME FIRST.
NEILL AND CO., PRINTERS, EDINBURGH.
DISSERTATION SIXTH:
EXHIBITING- A GENERAL VIEW
OF THE
PKOGRESS OP MATHEMATICAL AND PHYSICAL SCIENCE,
PRINCIPALLY FROM 1775 TO 1850.
By JAMES DAVID FORBES, D.C.L., F.R.S., Sec. R.S. Ed.
PROFESSOR OF NATURAL PHILOSOPHY IN THE UNIVERSITY OF EDINBURGH,
AND CORRESPONDING MEMBER OF THE INSTITUTE OF FRANCE.
• . '
J
•
CONTENTS OF THE SIXTH DISSERTATION.
CHAPTER I.—INTRODUCTORY.
On the Plan of this Dissertation Page 799
§ 2. On the relations between Mathematics and Natural
Philosophy,
Arts 
and between the latter and the Mechanical
 page 805
HAPTER II-—PHYSICAL ASTRONOMY AND ANALYTICAL MECHANICS
§ 1. Lagrange.— Variation of Parameters—Application
to Physical Astronomy. The Stability of the Planetary
System ; Laplace ; Poisson. Moon's Ijibration..p&gQ 809
§ 2. Laplace.—Dunar Theory Improved.—Great Ine¬
quality of Jupiter and Saturn.—Theory of the Tides
—Young; Dr Whewell; Mr Airy.—Theory of Pro¬
babilities—Character of Laplace as a Physicist and
§ 3. Legendre.—Ivory.—Theory of Integration ; El¬
liptic Transcendants (Abel, Jacobi). The Attraction
of Spheroids, and Theory of the Earth's Figure. At¬
mospherical Refractions   page 822
§ 4. Progress of Physical Astronomy since the publication
of the Mecanique Celeste—Poisson.—Theory of Ro¬
tation (Poinsot).—Mr Airy—77te Solar Theory.—
MM. Plana and Hansen—The Lunar Theory. 
Physical Astronomy in America page 824
§ 5. M. Leverrier—Air Adams.—The inverse method
of Perturbations. Prediction of the place and orbit of
Neptune from the motions of Uranus page 827
CHAPTER III.-
§ 1. Maskelyne—Delambre.—Progress of Practical
Astronomy from 1770 till 1810—o/ the Lunar Theory
deduced from Observation—The Density and Figure of
the Globe. Cavendish ; V&ily.—Trigonometrical Sur-
  page 832
§ 2. Sir William Herschel—History of Sidereal and
Telescopic Astronomy to 1820. Herschel as an Opti¬
cian—Planet Uranus—Solar Spots—Orbits of Double
Stars Nebulce—The Milky Way—Sun's Motion in
SPace page 838
§ 3. Bessel—Mr Airy—Modern Observatories. Fixed
Star Catalogues—Planetary and Lunar Observa-
ti°ns page 847
§ 4. Borda—Kater—Baily. The Figure of the Earth
from Pendulum Observations—“Reduction to a va-
■ASTRONOMY.
cuumf' Mr Stokes.—Colonel Everest — M.
Struve Latest Measures of the Earth. Al. Fou¬
cault’s Pendulum Experiment page 850
§ 5. M. Encke. Cometary Astronomy—Periodic Comets
of Halley and Encke. G ambart’s and Biela’s Co¬
met-Comets of 1811 and 1843.—Air Hind—Aew
Planets or Asteroids. Air Lassell—Newly disco¬
vered Satellites. Mr Bond page 855
§ 6. Sidereal Astronomy since 1820.—AI. Struve 
Double Stars. Observatories of Dor pat and Pulkowa.
Sir John Herschel—Orto of Double Stars. Mag¬
nitudes of Stars. Variable Stars. Earl OF Rosse
—His Telescopes. Nebulce. Henderson and Bes¬
sel—Parallax of Stars   page ggl
CHAPTER IV.—MECHANICS OF SOLID AND FLUID BODIES, CIVIL ENGINEERING,
AND ACOUSTICS.
§ 1. Watt.—Condition of Practical Mechanics previous
to the time of Watt. His genius for the application
of Science to Practice. His successive Improvements
on the Steam-Engine. Steam Navigation page 865
§ 2. Robison.—Application of Statical Principles to
Engineering—especially to practical Masonry. Cou¬
lomb.—Friction—Force of Torsion page 870
§ 3. Thomas Young—Strength of Materials, and Art
of Construction (continued).—Telford—Introduc¬
tion of Iron into permanent Structures. Suspension
Bridges—Tredgold; Air Hodgkinson ; Al. Navier.—
Air Robert Stephenson — Tubular Bridges....p&gQ 874
§ 4. Sir M. I. Brunel.—Self-acting Machinery.—Thames
Tunnel.—Air Babbage’s Calculating Engines.. .page 878
§ 5. Trevithick.—George Stephenson.—The Loco¬
motive Steam-Engine.—Rise and Progress of Rail¬
ways.—M. de Pambour on Locomotives Page 881
§ 6. Hydrodynamics—Dubuat, Venturi, Professor
Stokes.—Friction and Resistance of Fluids.—AIM.
Weber, Air Scott Russell — Propagation of
Waves. Their influence on Canal Navigation.—AIM.
Fourneyron and Poncelet—Improved Hydraulic
Machines; Turbine. Reference to the subject of Capil¬
lary Attraction  page 886
§ 7. Progress of Acoustics. Chladni—Savart — La¬
place's Correction of the Theory of Sound. Vibrating
Plates and Acoustic Figures. Cagniard de la Tour’s
“ Sirene.”  page 891
796
CONTENTS,
CHAPTER Y.—OPTICS.
§ 1. Thomas Young.—Undulatory Theory of Light.
 Its History from the time of Hooke and Huygens—
The Law of Interference.—Its application to Diffrac¬
tion to the Rainbow—and to other subjects. The
Theory of Polarization referred to another secfion...page 893
§ 2. Malus.—Discovery of the Polarization of Light by
Reflection.—Early History of Double Refraction and
Polarization   901
§ 3. Fresnel.—The Undulatory Theory of Light con¬
tinued.—Diffraction.— Transverse Vibrations; Young.
 Polarization and Dduble Refraction explained.—•
Lighthouse Illumination Page 903
§ 4. Arago.—Short Account of his Scientific Career—He
discovers the Colours of Polarized Light—Laws and
Theory of Depolarization ; M. Biot; Young ; Fres¬
nel.—Non-interference of oppositely Polarized Rays—
Rotatory Action of Quartz.—M. Foucault’s Experi¬
ment on the Velocity of Light Page 907
§ 5. Sir David Brewster—Progress of Experimental
Optics—Laws of Polarization—Double Refraction pro¬
duced by Heat and Compression—Discovery of Biaxal
Crystals—Laws of Metallic Reflection—Absorption of
Light; and Lines of the Solar Spectrum; Fraun¬
hofer.— Seebeck ; M. Biot pag® 911
§ 6. Mr Airy, Sir William R. Hamilton, and Profes¬
sors Lloyd and Maccullagh.— Confirmation of
Fresnel's Theory—Investigation of the Wave Surface
completed; Conical Refraction.—M. Cauchy—Me¬
chanical Theory of Elastic Media, and of Ordinary and
Metallic Reflection ; M. Jamin.—Theory of Dispersion ;
Professor Powell pag® 917
§ 7. Ritter.—Chemical Rays of the Spectrum.—Niepce;
Daguerre ; Mr Talbot. Art of Heliography or
Photography — Daguerreotype — Calotype.— Professor
Stokes. Chemical Rays rendered visible—Fluores¬
cence Page 921
CHAPTER VI.—HEAT, INCLUDING SOME TOPICS OF CHEMICAL PHILOSOPHY.
§ 1. Black.— Latent and Specific Heat.—Irvine.—Hut¬
ton.—Doctrines of Heat applied to some Natural Phe¬
nomena Page 925
§ 2. Cavendish.— His Singular Character and Attain¬
ments—Eminent Chemical Discoveries—Observations
on Heat and on other Branches of Physics.—Lavoi-
Sjf.R—The Calorimeter—Theory of Combustion and of
Oxidation Page 928
§ 3. Dalton.— Theory of Gases and Vapours—Law of
Expansion by Heat—Atomic Theory of Chemistry.—
Gay Lussac  Page 933
§ 4. llUMFORD.—Economical applications of Heat—Point
of Maximum Density of Water ; Hope.—Friction as a
source of Heat. Theory that Heat is convertible into
Mechanical Energy ; Mr Joule Page 940
§ 5. Sir John Leslie.—Establishment of certain Laws
of Radiant .Heat.—Pictet.—Prevost page 942
§ 6. Fourier.—Mathematical Theory of the Conduction
of Heat—Lambert; Poisson.—Temperature of the
Earth and of Space Pag° 946
§ 7. Dulong.—The Law of Cooling.—Progress of the Sci¬
ence of Radiant Heat between Leslie's and Mclloni's
Discoveries ; transmission of Radiant Heat through
Glass. Herschel; De la Roche ; Professor Powell.
— Theory of Dew; Wells Page 952
§ 8. Melloni.—Recent History of Radiant Heat—
Transmission and Refraction of Heat; Properties of
Heat analogous to Colour—Experiments in Great
Britain on the Polarization and Double Refraction of
Heat   955
§ 9. M. Regnault.—Numerical Laws of Expansion by
Heat ; Rudberg.— Vaporization ; Dulong.—Latent
Heat; Hygrometry page 957
CHAPTER VII.—ELECTRICITY—MAGNETISM—ELECTRO-MAGNETISM.
§ 1. Galvani.—Discovery of Galvanism ; Proper Animal
Electricity.—The subject revived by Nobili.—MM. Mat-
teucci and Du Bois-Rejrmond  Page 958
§ 2. Volta.—Progress of Discovery in Common and At¬
mospheric Electricity—The Electro-motive Theory—
Voltaic Pile—Chemical Analogies and Decomposition
Fabbroni; Nicholson and Carlisle  Page 961
§ 3. Sir Humphry Davy. Progress of Voltaic Electri¬
city— Electro-Chemistry; Berzelius.—Davy's Inven¬
tion of the Safety-Lamp.—Wollaston ; his Electri¬
cal and other Observations. Contrast of his Charac¬
ter with that of Davy  page 966
§ 4. Oersted.—AyiPKnE .—Discovery of Electro-Magnet¬
ism—Electro-Dynamic Theory—Discovery of Thermo-
Electricity; Seebeck. The Galvanometer of Schweig-
ger and Nobili Page 973
§ 5. Dr Faraday.—Progress of the Theory of Electro-Che¬
mical Decomposition — Volta-Electric Induction —
Magneto-Electricity—Diamagnetism— Optical Changes
induced by Magnetism.—Professor Pliicker—Magne-
optic Action    977
§ 6. Ohm—Daniell—Mr Wheatstone—M. Jacobi.
—Laws of Electrical Conduction ;—Constant Battery;
—Applications of Electricity to Telegraphs—Clocks
Motive Engines—the Electrotype   Page 982
§ 7. Cavendish—Coulomb.— On the Distribution of Sta¬
tical Electricity, and on the Mathematical Theory of
the same.—Poisson.—Mathematical Theory of Stati¬
cal Electricity and of Magnetism generalized. Green ;
Professor William Thomson Page 987
§ 8. Professor Hansteen—Baron A. von Humboldt—
Gauss—Major-General Sabine—Captain Sir J. C.
Ross.—Progress of our Knowledge of Terrestrial Mag¬
netism in the Present Century Page 990
CONSULTING INDEX
TO THE
PRINCIPAL NAMES AND SUBJECTS* MENTIONED IN THE FOLLOWING- DISSERTATION.
The References are to the Anicius or Paragraphs, not to the Pages.
Ahel, 98.
Absorption of Light, 536.
Acceleration of the Moon, Secular, 62.
Acoustics, 433, &c.
Adams, Mr, 127, &c.
Airy, Mr, 82,115,228, &c.; 421, 549,879.
Ampere, 792, 794, &c.
Arago, 166, 500, 792.
Asteroids, 282. List of, 283, and Addi¬
tions, p. 996.
Astronomy, Physical, 41, &c.; Practical,
149, &c. j 218, &c.; Sidereal, 172, &c.;
289, &c.
Atomic Theory, Dalton’s, 618.
Attraction of Spheroids, 99, &c.; of Moun¬
tains, 154, &c.
Attractions, Theorems about, 99, &c. ;
S77, 905.
Bahbage, Mr, 377.
Baily, 158, 242, &c.
Balloon ascents, 630, and note.
Barlow, Mr, 879.
Berzelius, 763, 767, and note.
Bessel, 221, 310.
Biaxal Crystals, 529 ; Theory of, 493.
Biot, M., 545, 662.
Black, 318, 583.
Block Machinery, 370.
Borda 237, &c.
Bowditch, 126.
Brewster, Sir David, 519, &c.
Bridges, Suspension, 351; Wooden, 356 ;
Girder, 358; Tubular, 359, &c.
Brinkley, 307, and note.
Brunei, Sir M. I., 366.
Cagniard de la Tour, M., 441.
Calculating Engine, 377.
Calorimeter, £8, 607.
Calotype, The, 571.
Canal Navigation, 422.
Capillary Attraction, 88, 432.
Catenary, 353.
Cauchy, M., 556.
Cavendish, 156, 593, &c.; 871.
Cavendish Experiment, 156, &c.
Chances, 83.
Chemical Subjects connected with Na¬
tural Philosophy, 582, 596, 618, &c.;
763, &c.; 811.
Chemical action of Light, 562.
Chemical Equivalents, 628.
Chemical Theory of Galvanism, 751, 763,
Chladni, 434.
Civil engineering, 312-431.
Clairaut, 235.
Clock, Electric, 231, 862.
Coloration of Heat, 713.
Combustion, 608, 775.
Comets, 262; Halley’s, 263; Encke’s,
267; Gambart’s or Biela’s, 276 ; Co¬
mets of 1811 and 1843, 281.
Conduction of Heat, 661, &c.
Conduction of Electricity, 813, 842.
Cornish Steam Engines, 323.
Conical Refraction, 551.
Cooling, Law of, 654, 694.
Coulomb, 339, 413, 873.
Daguerre, 569.
Dalton, (TlO, 721, note.
Daniell, 852.
Davy. Sir H., 758, &c.; 792, 808.
Declination of the Needle, 881.
Delambre, 164, &c.
De la Roche, 704.
Density of the Earth, 154, &c.
Depolarization, 505.
Detrusion, 346.
Diamagnetism, 823.
Diffraction of Light, 458, 486, &c.
Dip, Magnetic, 882, note ; 883.
Discontinuous functions, 31, 685.
Dispersion of Light, 559.
Double Refraction, 475, &c.
Du Bois-Reymond, M., 739.
Dubuat, 410.
Dulong, 693, 721.
Earth’s Figure, 163, 234, 249, &c.; Den¬
sity, 154, &c.; Rotation, 258.
Earth, Proper Heat of the, 675.
Economical application of Heat, 634.
Elastic Solids, 342, &c.
Electricity, 728, &c.; Animal, 734, 738,
872; Atmospheric, 743; Mathemati¬
cal Theory of, 869, &c.; Distribution
of, 871, 874.
Electric Telegraph and Clock, 856, &c.
Electro-Chemistry, 751, 754, 763, 811.
Electrodynamic Machines, 866.
Electro-Magnetism, 786, &c.
Electrotype, 868.
Ellipticity of the Earth, 256.
Ellis, Mr Leslie, 20, note; 86.
Emanation of Radiant Heat, 651, 667.
Encke, M. 262, &c.; Encke’s Comet,267.
English Arc of Meridian, 167.
Erman, M. Ad., 885.
Evaporation, 613, 744.
Everest, Colonel, 250.
Expansion of the Gases, 617, 721, and
note.
Fabbroni, 751.
Fairbairn, Mr W., 363.
Faraday, Dr, 798, 807, &c.
Fechncr, 851.
Figure of the Earth, 163, &c.; 234, &c.
249, &c.; Kesults, 258.
Flame, 770.
Flexure of Beams, 347, &c.
Fluids, Friction and Resistance of, 410.
Fluorescence, 579.
Foucault, M., 258, 514.
Fourier, 663, &c.
Fourneyron's Turbine, 427.
Fraunhofer, 538.
French Arc of Meridian, 165.
French experimenters, Skill of, 720.
Fresnel, 468, 485, &c.
Frog, Electricity of the, 734.
Galle, M., 137.
Galloway, 212.
Galvani, 728, &c.
Galvanism, Discovery of, 732.
Gases and Vapours, Dalton’s Theory of,
613, 615, 617.
Gauss, 48, 856, 896.
Gay-Lussac, 617, 625, 630.
Green, 558 and note, 878.
Greenwich Observatory, 150, 159, 227.
Gregory, Duncan, 31, note.
Halley, 882.
Hamilton, Sir W. K., 550, 552, note.
Hansen, M., 57, note-, 122, &c., 261.
Hansteen, Professor, 881, &c.
Heat, 582, &e.; Economical Applica¬
tions of, 634; Hypothesis on the Na¬
ture of, 639; Radiant, 641, &c.; 692,
&c.; Mathematical Theory of, 661, &c.;
Motion in a Sphere, 673; Solar, 679.
Heliometer, 310.
Henderson, 304.
Herschel, Caroline, 269, note.
Herschel, Sir J. F. W., 294 549.
Herschel, Sir William, 172,’&c.702.
Hind, Mr, 282.
Historic periods in Science, 2, &c.
Hodgkinson, Mr, 352, 353, 363.
Hooke, 452.
Hope, 636.
* For the Grounds of Selection of these, and on the Use of the Index, see Articles (13) and (23).
INDEX.
798
Humboldt, Baron A.
Hutton, 591.
Huygens, 453, 475.
454.
von, 734, 892, &c.
The Principle of,
Hydrodynamics, 408, &c.
Hygrometry, 614, 727.
Indian Arc of Meridian, 250.
Induction of Electric Currents, 81b.
Inequalities, Secular and Periodic, 47.
Intensity, Magnetic, 885, 911.
Integration, 31, 97. . .
Interference of Light, 460; of Chemical
Rays, 565.
Isothermal Lines, 894.
Irvine, 586, 589.
Ivory, 103.
Jacobi, C. G. I., 98.
Jacobi, Mr M. H., 848, 868.
Jamin, M., 557.
Joule, Mr, 640.
Jupiter and Saturn, Theory of, 65.
Kelland, Professor, 421, 690.
Kater, 240.
Lagrange, 20, note; 41, &c., 90.
Lalande, 162.
Lambert, 661.
Lambton, 250.
Laplace, 51, 60, &c., 199, 235, note, 433.
Lassell, Mr, 284.
Latent Heat, 584, &c., 599, 724.
Lavoisier, 605.
Legendre, 85, 95, &c.
Leslie, Sir John, 641, &c.
Leverrier, M., 127, &c.
Lihration of the Moon, 57.
Lines of the Spectrum, 538.
Lighthouses, 496.
Lloyd, Dr., 550, &c., 900, 910.
Locomotive Engine, 383, &c.
Lubbock, Sir J. W., 79, 117.
Luminous Waves, Length of, 463.
Lunar Observations, 152, 229.
Lunar Theory, 61, &c., 118, &c., 229.
Maccullagh, 553.
Magne-crystallic Force, 832.
Magne-optic Force, 831.
Magnetism, Terrestrial, 880, &c.; Theory
of, 903.
Magneto-electricity, 819.
Magnifying Power, 179,180.
Malus, 474.
Maskelyne, 150.
Mathematics, Pure, 20, 24, 28, &c.
Mathematical Theory of Heat, 661, &c.;
of Electricity, 869, &c.; of Magnetism,
903.
Matteucci, 739.
“ Mecanique Celeste,” 89.
Mechain, 166.
Mechanical Arts, 11, 32, &c.
Mechanical Notation, 378.
Mechanics, 312, &c.
Melloni, 707.
Metallic Polarization, 534.
Michell, 86, note, 156, 340.
Milky Way, 201, &c.
Miller, Patrick, 325.
Modulus of Elasticity, 345.
Natural Philosophy, its Connection with
Mathematics, 24; with the Mechanical
Arts, 32, &c.
Nautical Almanac, 153.
Navicr, M., 354.
Nebulae, 190, 302.
Nebular Theory, 198, &c.
Neptune, Discovery of, 127, &c.; Ele¬
ments of, 143.
Nicholson and Carlisle, 754.
Niepce, Nicephore, 569.
Nobili, 708, 738, 802.
Oersted, 786, &c., 803, &c.
Olbers, 161.
Ohm, 840.
Optics, 444, &c.
Parallax of Stars, 188, 306, &c.
Parameters, Variation of, 44.
Pendulum Observations, 236; M. Fou¬
cault’s Pendulum, 258.
Perturbations, Planetary, 46.
Peters, M., 311.
Photography, 567.
Pictet, 648.
Pile of Volta, 750, 752.
Plana, M., 118, &c.
Planets, New small, 282, &c.
Playfair, 16, note.
Plenitude of Stars, 203.
Pliicker, Professor, 831.
Poinsot, M., 113.
Poisson, 55, 112, &c., 689.
Polarization of Light, 474, &c., 525, &c.;
affected by Magnetic Actions, 834 ; of
Heat, 717; of Chemical Rays, 565;
Circular, 491; by Metals, 534.
Poles, Terrestrial Magnetic, 882, 884.
Poncelet, M., 431.
Pond, 227, 307.
Potential, 877, 905.
Powell, Professor, 560, 705.
Prevost, 649.
Probabilities, 83.
Proper Motions of Stars, 209, &c.
Pulkowa, Observatory of, 293.
Quartz, Optical Properties of, 511.
Quaternions, 552, note.
Radiant Heat, 641, &c., 692, &c.
Railways, History of, 398.
Rainbow, Theory of the, 465.
Reflection and Refraction of Light, 490.
Refrangibility of Heat, 714.
Refractions, Astronomical, 107.
Regnault, M., 719, &c.
Rheostat, 848.
Ritter, 563.
Rivers, Theory of, 410.
Robison, 329, &c., 749.
Ross, Sir J. C., 884, 910.
Rosse, Earl of, 299.
Rotation of the Earth, 258.
Royal Institution, 637.
Rumford, 632, &c.; Rumford Prize, 637.
Russell, Mr J. S., 421.
Russo-Scandinav ian Arc of Meridian,254.
Sabine, Major-General, 238, 246, 909.
Safety Lamp, 393, 770.
Satellites, New, 284.
Savart, 441.
Schehallien Experiment, 155.
Scheutz, M., 380.
Schweigger, 802.
Seebeck, 512, 544, 801.
Ships, Magnetism of, 879.
“ Sirene,” 441.
Slide-Rest, and Planing Machine, 372.
Solar Heat, 679.
Somerville, Mrs, 566 and note.
Sound, Theory of, 433.
Specific Heat, 588, 599, 607, 727.
Spectrum, Lines of the, 538; Heat of the,
702, 715.
Stability of the Solar System, 50.
Stars, Double, 187, 291, 296; Proper
Motions of, 209, 292; Parallax of, 188,
306 ; Brightness of, 297; Variable,
298.
Steam, Elastic Force of, 699.
Steam Carriage, 384.
Steam Engine, 317, &c.
Steam Navigation, 325.
Stephenson, George, 392, &C.
Stephenson, Mr R., 355, &c.
Stereoscope, 581.
Stokes, Professor, 235, note; 247, 416,
579 691.
Struve, M. W., 209, note; 252, 290, &c.
Sun, The, 185.
Suspension Bridges, 351.
Talbot, Mr Fox, 571.
Telegraph, Electric, 856.
Telescopes, 178, &c., 299, &c.
Telford, 351.
Thermo-electricity, 801.
Thermo-multiplier, 709.
Thomson, Professor W., 878.
Tides, 69, &c.
Torpedo, 872.
Torsion Balance, 157, 340, 874.
Transverse Vibrations, 488.
Tredgold, 352.
Trevithick, 385, &c.
Turbine, 425.
Tunnel, The Thames, 373.
Undulatory Theory of Light, 452, &c.
Uranus, Discovery of, 183; Perturbations
of, 132, &c.
Variable Stars, 298.
Variation or Declination of the Needle,
881.
Variation of Parameters, 44.
Venturi, 413.
Venus and the Earth, long Inequality of,
115.
Vision, 471, 581.
Volta, 740, &c.
Volta-electric Induction, 817.
Voltaic Pile, 749.
Waves, Theory of, 419, &c.
Water, Composition of, 597; Maximum
Density of, 636.
Water Wheels, 426.
Watt, James, 312, &c., 597.
Weber, The MM., 420, 856, 899.
Wells, 706.
Wheatstone, Mr, 581, 853, &c.
Whewell, Dr, 19, 79.
Wilson, P., 185.
Wollaston, 476, 538, 564, 780, &c.
Young, Thomas, 80, 342, &c., 445, &c.,
488, 506, 780.
DISSERTATION SIXTH.
MATHEMATICAL AND PHYSICAL SCIENCE.
CHAPTER I.
INTRODUCTORY.
§ 1. On ike Plan of this Dissertation.
(!•) The year 1850 may be said to complete tbe Third cen-
vances mo^ern scientific progress, or the Fourth if
b Science. we inc^ude earliest dawn. To each of these ages
of discovery may be assigned a peculiarity in the cha¬
racter of its improvements, and even in the methods
which conduced to that improvement.
(2.) Between 1450 and 1550 (a period so distinguished
l450°l,rjr)O ^ *etters anc^ t^ie arts)’ some great truths in physics
• and mathematics had presented themselves to a few
precocious minds, yet they had not received any
public acknowledgment, nor perhaps an adequate de¬
monstration. Algebra then first became a science.
Leonardo da Vinci made the earliest steps since the
time of Archimedes, in rational mechanics, and Co¬
pernicus almost at the close of this period promul¬
gated the true system of the world.
(3 ) But the next centenary (1550-1650) was the first
1550°-1650 ^rue sc^ent^c activity. Its characteristic feature
' was the vindication of observation and experiment as
the prime essentials to the increase of natural know¬
ledge, with the consequent repudiation of the dogmas
of the schoolmen, and the baseless methods of d priori
reasoning. The men of science formed a goodly array
at this stirring time ; and signal were their triumphs.
Galileo was beyond all comparison the glory of his
age. His sagacity, his knowledge, his versatility of
talent, his ingenuity as an inventor, his success in
prosecuting his discoveries, and his zeal and elo¬
quence in making known their importance, gave him
an enviable pre-eminence even amidst a mighty gene¬
ration. Bacon laid down the canons of a new method
in philosophy which Gilbert and Kepler, as well as
Galileo, had already acted on. Napier and Descartes
prepared for the general application of mathematics
in the coming struggle.
The hundred years which next succeeded (1650- G )
1750) saw the triumphant application of mathema-^g^od17r()
tics to Mechanics and Physics, and the establishment
of the greatest mechanical theory of any age, that of
Gravitation. The preparatory labours of a hundred
and fifty years were brought, chiefly by the unparal¬
leled sagacity and genius of Newton, to a speedy and
dazzling climax. His success brought numerous and
worthy labourers into the field, but they found enough
to do in gathering in the harvest which he had pre¬
pared for them.
If we look for the distinguishing characteristic of (5.)
the centenary period just elapsed (1750-1850), wePeriod
find it in this,—that it has drawn far more largely*"^ 18j0.
upon Experiment as a means of arriving at truth than
had previously been done. By a natural conversion
of the process, the knowledge thus acquired has
been applied with more freedom and boldness to
the exigencies of mankind, and to the farther in¬
vestigation of the secrets of nature. If we com¬
pare the now extensive subjects of Heat, Electri-
city, and Magnetism, with the mere rudiments of
these sciences as understood in 1750, or if we think
of the astonishing revival of physical and experi¬
mental Optics (which had well nigh slumbered for
more than a century) during the too short lives of
Young and Fresnel, we shall be disposed to admit
800
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
the former part of the statement; and when we recol¬
lect that the same period has given birth to the steam-
engine of Watt, with its application to shipping and
railways,—-to the gigantic telescopes of Herschel and
Lord Itosse, wonderful as works of art as well as in¬
struments of sublime discovery,—to the electric tele¬
graph, and to the tubular bridge,—we shall be ready
to grant the last part of the proposition, that science
and art have been more indissolubly united than at
any previous period.
(6.) The Dissertation of Professor Playfair closes with
Limits of the period of Newton ; that of Sir John Leslie, pro-
tins Disser- fesse(]iy devoted to the history of the eighteenth cen¬
tury, embraces some matters which belong more
properly to those which preceded and followed it.
After considering how I might best carry out the plan
of these essays, I have adopted the period from about
the year 1775 to 1850 as the general limit of my
review. We may imagine this period, of three quar¬
ters of a century preceding the present time, to be
divided into three lesser intervals of 25 years each,
which have also some peculiar features of their own.
(7.) From 1775 to 1800 many branches of science still
Character continued in the comparatively inert state which cha-
oftheeC180thracterized a £reat Par^ °f the eighteenth century,
century. There were, however, two or three notable excep¬
tions. One was the continued successful solution of
the outstanding difficulties of the Theory of Gravity
applied to the moon and planets, a task in which the
continental mathematicians, and of these, in chief,
Lagrange and Laplace, had no rivals, or even coad¬
jutors, on this side of the channel: Another was the
foundation of Sidereal Astronomy by Sir William
Herschel; and the last was the commencement of a
system of Chemical Philosophy based on new and im¬
portant experiments, and including the laws of heat
in combination with matter, which at that period very
naturally ranged themselves within the province of
the chemist. In this department two British and
one foreign name stand conspicuous, Black, Caven¬
dish, and Lavoisier. I do not of course mean to affirm
that other branches of science were not cultivated
with success within the exact period of which we
speak. Electricity, for instance, first statical, after¬
wards that of the pile, had a share in the discoveries
and speculations of the time. But these were rather
the mere extension of what had previously been thought
of; or the first dawn of future important results, whose
development fills a large space in the succeeding story.
Volta and his inventions belong rather to the nine¬
teenth than to the eighteenth century.
(8.) The first quarter of the present century attained
Character a higher and more universal celebrity. Scarcely a
oft.he, branch of physical science but received important
1800-1825. and even capital additions. Physical Astronomy in¬
deed, no longer filled so large a space in the page of
discovery, simply because the exhaustive labours of
the geometers of the former period had brought it to
a stage of perfection nearly co-ordinate with the means
of observation, and because, by the publication of the
Mecanique Celeste, Laplace had rendered available Mecanique
and precise the masses of scattered research accu- e ep
mulated by the labours of a century since the close
of Newton’s career of discovery. It was in some
sense a new book of “ Principia,”—not, indeed,
the work of one, but of many; nor of a few years,
but of two generations at least. Still there it was,
a great monument of successful toil, which, like its
prototype, was for many years to be studied, even by
minds of the highest order, rather than to be enlarged.
But the other branches of Natural Philosophy (9.)
were now to make a stride, such as perhaps no pre-
ceding time had witnessed. The science of Optics p^°g^c8>
was speedily expanded almost twofold, both in its
facts and in its doctrines. Galvanic Electricity dis¬
closed a series of phenomena not less brilliant and
unexpected in themselves than important from the new
light they threw on the still dawning science of che¬
mistry, and from the power of the tool which they
placed in the hands of philosophers. Before the
first quarter of the present century closed, the import¬
ant and long suspected connection between Electricity
and Magnetism was revealed, and its immediate con¬
sequences had been traced out with almost unpa¬
ralleled ingenuity and expedition. The basis of the
science of Badiant Heat, slightly anticipated by the
philosophers of the eighteenth and even the seven¬
teenth centuries (Lambert and Mariotte), wras finally
laid in a distinct form, assigning to the agent, heat,
an independent position dissociated from grosser
matter, such as light had long enjoyed. Astronomy,
though enriched on the very first night of the new
century by the discovery of a small planet, the he¬
rald of so many more of the same class, made per¬
haps less signal progress ; but Chemistry, besides the
aid it received from the invention of the pile, had a
triumph peculiarly its own in the addition of the
comprehensive doctrine of Definite Proportions, des¬
tined to throw at some later time a steady light on
the vexed question of the constitution of matter.
The great number of scientific names of the first or¬
der of merit concerned in these numerous discoveries
marks the extraordinary fertility of the period. They
are imperfectly comprehended in the following list:
Young, Malus, Sir David Brewster, Fresnel, and
Arago ; Volta, Dalton, Davy, and Oersted ; Prevost,
Leslie, and Fourier; Gauss, Ivory, Olbers, Bessel,
and Encke.
Of the twenty-five years just elapsed, it is not so ^ 0^-)
easy to speak with precision. The voice of criticism
may be fairly uttered with that reserve which every
one must feel in speaking of his immediate contem¬
poraries. Yet it may perhaps be stated without
just cause either of offence or regret, that it has not
on the whole been characterized by the full maturity
of so many commanding minds. Of the great dis-
coverers of the former period, several survived and
continued their efficient labours during no small por-
Chap. L, § 1.]
PLAN OF THIS DISSERTATION.
801
tion of the latter ; and a few happily still remain to
claim the respect and veneration of their disciples
and successors. But the vast steps so recently made
in Optics, in Electricity, in Magnetism, in Thermotics,
and in Chemical principles, tended of necessity to call
forth such an amount of laborious detail in the de¬
fining and connecting of facts and laws, and the de¬
ductions of the theories started to explain them, as
seemed to render fresh and striking originality some¬
what hopeless, whilst they occasioned a vast amount
of useful employment to minds of every order of ta-
Optics. lent. The undulatory Theory of Light, nobly blocked
out by the massive labours of Young and Fresnel,
has afforded still unexhausted material to the ma¬
thematician on the one hand, and to the experimen¬
talist on the other; and ably have they fulfilled the
double task, adding at the same time discoveries
whose importance and difficulty would have made
them still more prominent, had they not been the
legitimate consequences of a still greater discovery
already in our possession. Nearly the same might
have been said for the sciences of Electricity, Electro¬
magnetism, and Electro-chemistry, had not the com-
Electricity. parative newness of the whole doctrine of these sci¬
ences, and the suddenness of their first rise, and, per¬
haps still more, the appearance of a philosopher of the
very highest merit, Mr Faraday, who fortunately at¬
tached himself to this special department, made the
last thirty years an almost unbroken period of dis¬
covery. Radiant Heat, too, has been successfully
advanced by labours comparable perhaps to those
which marked its first rise as a science, and some
other topics connected with heat have risen into
great and practical consequence. Astronomy has
been prosecuted with a systematic assiduity and suc¬
cess, especially at the British and Russian national
observatories, which yields to that of no former pe¬
riod, whilst physical astronomy has been cultivated
by methods of still improved analysis, and has
achieved one triumph which France need not grudge
to England, nor England to France,—so signal as
to be placed by common consent in a position su¬
perior to any since the first publication of the theory
of gravitation, more than a century and a half be¬
fore. This was the prediction of the position in
space of a planet whose existence was unknown ex¬
cept by the disturbance which it produced in the
Magnetism, movements of another. Terrestrial Magnetism has,
for the first time, aspired to the rank of an exact
science. In an illustrious philosopher of Germany,
it has found its Kepler ; and the combination of na¬
tional efforts in collecting reliable data from the re¬
motest corners of the globe is characteristic of the
Chemistry, practical energy of the age. Pure Chemistry has
been cultivated with extraordinary assiduity; but
though some general principles have emerged, none
are comparable, from their importance, to the dis¬
covery of Dalton. To cite, then, at present, but a
few names, amongst the most conspicuous benefac-
VOL. i.
Heat.
Astrono¬
my.
tors of science of the last, or contemporary period, are
MM. Airy, Cauchy, Hamilton, and MacCullagh ;
MM. Faraday, Melloni, and Gauss ; Sir John Her-
schel, M. Struve, and Lord Rosse; MM. Plana,
Poisson, Leverrier, and Adams ; MM. Mitscherlich,
Liebig, and Dumas.
It seems to me impossible to exclude from a re- (H-)
view, however slight, of contemporary progress inMechaui
the exact sciences, the advances which have accrued
to them both directly, and, as it were, reflexively, by
the astonishing progress of the Mechanical Arts. The
causes, indeed, which called them forth are some¬
what different from those which are active in more
abstract, though scarcely more difficult, studies.
Increasing national wealth, numbers, and enterprise,
are stimulants unlike the laurels, or even the golden
medals of academies, and the quiet applause of a few
studious men. But the result is not less real, and
the advance of knowledge scarcely more indirect.
The masterpieces of civil engineering—the Steam
Engine, the Locomotive Engine, and the Tubular
Bridge—are only experiments on the powers of nature
on a gigantic scale, and are not to be compassed
without inductive skill as remarkable and as truly
philosophic as any effort which the man of science
exerts, save only the origination of great theories, of
which one or two in a hundred years may be con¬
sidered as a liberal allowance. Whilst then we
claim for Watt a place amongst the eminent contri¬
butors to the progress of science in the eighteenth
century, we must reserve a similar one for the Ste¬
phensons and the Brunels of the present: and
whilst we are proud of the changes wrought by the
increase of knowledge during the last twenty-five
years on the face of society, we must recollect that
these very changes, and the inventions which have
occasioned them, have stamped perhaps the most
characteristic feature—its intense pi-acticalness—on
the science itself of the same period.
Having thus briefly reviewed the course of disco- (12.)
very since the latter portion of the eighteenth centxiry, Review of
I proceed in the succeeding chapters to attempt to of'sdence^
sketch it more in detail, dividing the sciences into in this
groups, and in each of these endeavouring to present Essay,
a lively view of its progress by connecting it with
the individual career of the eminent men who have
most contributed thereto, and introducing collaterally
the chief results obtained by their contemporaries.
In this manner I hope, on the one hand, to escape the
formality of a history of science, and the meagre de¬
tail which our limits would prescribe to so vast a sub¬
ject ; and on the other to be enabled to impress upon
the reader (as seems to be the design of these Essays)
the leading facts and features of discovery in every
age, together with the intellectual characteristics of
the greatest minds which contributed to it.
It is with no overweening confidence that I lay the (13.)
5 1
802
[Diss. VI.
MATHEMATICAL AND PHYSICAL SCIENCE.
Scheme of result of this attempt before the reader. _ During the
treatment lengthened period of composition of this Dissertation
of the sub- protractedby indisposition and untoward circumstances
jeCt- of different kinds, I have had abundant leisure to reflect
on the advantages and disadvantages of a plan which I
had sketched in the previous paragraphs, at the very
opening of my task. I am aware that a rigid criti¬
cism awaits every attempt like the present. I am
aware also, that it is far easier to detect real faults,
especially of omission, than to make sufficient allow¬
ance for the exceeding difficulty and delicacy of the
undertaking. I have but one ground of confidence,
and that is so strong, that I trust it will enable me
calmly to meet every just critical reflection. I am
conscious of having written in a spirit of absolute
impartiality whether as regards persons or subjects,
and that I have exercised to the full amount of my
opportunities what powers of judgment I possess.
I have striven to speak judicially and historically
whether of friend or stranger, the dead or the living,
Englishman or Foreigner. What I have felt the
most constant effort, has been the needful exclusion
of meritorious names, far more numerous than those
especially included and dwelt upon in these pages.
But this has appeared to me the cardinal point of
my whole plan. The labourers in science have been
in these latter days so numerous, that had I noticed,
even briefly, every one who had made a real step in
science, my pages must have been crowded by names
and titles of books. Even with the extension of bulk
to which this essay has gradually and unavoidably
grown (nearlv double of its projected amount), the
reader would rather have been bewildered than led by
the perusal of such a catalogue. Besides, since such
a brief historical synopsis forms very generally an in¬
troduction to the several articles of the Encyclopaadia,
to repeat it all here would have been but a tedious re-
dundancv. No one conversant with such matters will
imagine that I have saved myself any labour by this
particularity of selection. On the contrary, it would
have cost no effort to enumerate under each subject
the living or recently deceased authors upon it who
are best known ; such a detail must have left a vague
and shadowy impression on the mind of the general
reader, and when regard is paid to the necessary limits
of the essay, and the multitude of technical details and
technical words which there is no space to define and
illustrate, it is plain that the perusal must have been
rendered as dry and unpalatable to those who seek
general and elementary yet clear ideas, as it would
have been tantalizing and unsatisfactory to the ac¬
complished student, or to the man of science in
search of particular historical details.
(14.) The end at which I have aimed is to select the
more striking land-marks of progress in each subject
in each age, and endeavour to connect them with the
character and position of all the more eminent dis¬
coverers, thus conveying to the general reader suffi¬
cient information on the limited number of particular
subjects discussed, and interesting him not only in
the science but in the individuals. Then, by a few
slighter touches only, and the mention of some
secondary names, to connect with one another these
brighter periods of eminent progress, in which every
country and every age feels a just pride.
That by many I shall be considered to have dwelt (15.)
too much on some eras of invention, and to have
omitted others not less important, is a difference of
judgment which it is impossible not to anticipate,
but equally impossible to prevent. I will only add
that I have endeavoured to extend my impartiality
to subjects as well as to persons; and that I have
not intentionally dwelt longer on the topics of my
own predilection than on those naturally considered
by other persons equally or more important. Many
subjects as well as persons familiarly known to me
are scarcely, if at all, mentioned in these pages. To
leave some definite and vivid impressions, selected
solely for their importance, on the mind of my reader,
has been the great object constantly before me during
the composition of this work.
It will be seen from the preceding paragraphs,
that I have deviated in some respects from the withthatof
scheme of my two distinguished predecessors in the the preced-
composition of the Dissertations on Science, Professor
Playfair and Sir John Leslie. The essay of the for¬
mer, which is the more finished and methodical, is
admirably adapted to the period of the history of
science of which he had principally to treat; the
period, namely, of Galileo, Bacon, Newton, and
Leibnitz. But the amount of material was smaller,
and the principle of selection was also much simpler.
The positive science of that age might almost be re¬
duced to two heads, Astronomy, including its mecha¬
nical principles, and Optics. It was an age not more
distinguished for the Truths it disclosed, than for
the invention and right appreciation of the Methods
of Discovery. Inductive Logic, and Mathematical
Logic applied for the first time to dynamics, very
justly claimed a place in a dissertation on the pro¬
gress of science, in a period when these preliminary
doctrines and discoveries were the stepping stones by
which even the basement story of the Temple of
Nature could alone be reached. The Philosophy of
Bacon and the discovery of Fluxions, occupied there¬
fore, with much reason, a large portion of Professor
Playfair’s beautiful Dissertation ; and it is impossible
to regret that an intellect so admirably qualified for
tracing and displaying the intimate and historical
connection of branches of knowledge so varied in
their principles and character, should have been thus
congenially employed, to the delight and edification
of readers of every degree of acquirement from the
highest to the humblest.1
1 In mentioning the name of my distinguished predecessor in the Chair of Natural Philosophy in the University of Min
burgh, I willingly take the opportunity of noticing, in a few words, his peculiar merits, to which the Dissertation
Chap. L, g 1.]
PLAN OF THIS DISSERTATION.
803
Extent^and Bufc tllG extended domain of the science of the
variety of last hundred years enhances vastly the difficulty of the
materials, subjects succinctly handled as one by Mr Playfair.
The mechanical and experimental sciences alone con¬
stitute a body of knowledge so large that it is arespon-
sibility sufficient for one person to attempt to grasp
them all, and to set forth in order the steps of pro¬
gress and improvement which have been so rapid, and
even so startling. Since some of these have scarcely
as yet been historically digested, and the broad
features of contemporary discovery have not been
gradually separated by the judgment of an impartial
posterity from those slighter though praiseworthy
details, which lapse of time and advance of know¬
ledge will throw into the shadows of distance,—this
difficult and most laborious task falls principally
upon the reviewer. The length and breadth of the
subject of Natural Philosophy, and the cumbrous
and scattered depositories of knowledge in which
its records must be sought, combine to render not
only the undertaking an arduous one, but the
result of it a good deal more bulky than might be
desired, or than was easily possible, in dealing with
the glorious, but compact, history of Newton’s age.
It might be compared to the difference between writ¬
ing a history of the Jews or Romans and that of the
whole of modern Europe.
Lokfof •The mere raaSrdtude of tlie undertaking, then,
induction. well excuse me from entering upon the cog¬
nate, but exceedingly distinct, subjects of the Logic
of Inductive Discovery and the progress of the Pure
Mathematics. But an equally sound reason might
be found in my consciousness of inadequacy to un¬
dertake, whatever had been the dimensions of my
work, a threefold scheme of such magnitude and
difficulty. I do not think that any one person could
be found to treat the whole as it ought to be treated,
and I am certain that I am not that person.
One attempt—a bold and successful one—has (19.)
been made, in our own day, to unite two of the Writings of
tW departments,-! mean the History and the
1 nilosophy ot the Inductive Sciences. An English art Mill,
philosopher of wonderful versatility, industry, and
power has erected a permanent monument to his
reputation in a voluminous work bearing the pre¬
ceding title.1 A slight inspection of that work will
show how impracticable and self-destructive a plan it
would have been to attempt anything like a syste¬
matic abridgment of such a mass of facts and specu¬
lations within our present limits. Mr J. Stuart Mill
has also published a work bearing on the origin of
our scientific knowledge, diametrically opposed in
principle to the preceding one, yet marked by great
ability.2 Such disquisitions belong more properly
to the philosophy of the human mind than of phy¬
sics. After all, be it remembered that whatever has
been learnt or discussed concerning the means of
arriving at truth in Natural Science, it is not pre¬
tended that we have recently become possessed of
any canons or rules of discovery superseding those
fundamental principles of observation and experi¬
ment so well laid down by Bacon, and practised both
present volume will bear an enduring testimony. Playfair’s original contributions to science were not so marked and consi- Character
derable as to justify me in including his name in the comparatively brief catalogue of discoverers chronicled in the succeeding 0f Professor
pages; but his efforts are nevertheless, deserving of notice, and indirectly were perhaps hardly less beneficial. He was a most Plavfair
patient and admiring student of the greatest mathematical writers of his time, and, when we consider the singularly backward ' ^
state of that science in Great Britain about the end of the last and commencement of the present century, it was of no slight im¬
portance to find a, man placed in the position of a public instructor able and willing to direct attention to the splendid achieve-
ments of the continental mathematicians. By his lectures both on Mathematics and Natural Philosophy—by his luminous articles
in the Edinburgh Review—by some of his original papers in the Transactions of the Royal Society of Edinburgh—be contributed
to this useful end, and would have done so still farther had he been enabled to complete the Dissertation which he so ably com¬
menced. He had an excellent mathematical capacity, and mathematical taste, rather than £>ower. His explanations, even of
matters of inherent difficulty, are perspicuous and popular, qualities possessed by few of his contemporaries. His style has been
pronounced by the highest authorities to be a model of clearness and eloquence. He was extensively read in subjects of meta-
p ysics and morals, as well as of pure science ; and by a combination of talent rare, I am inclined to say, in a high degree, his
taste, though eminently mathematical, was also directed, with signal success (at first through his intimate friendship for Dr Hutton)
to t. e very opposite studies of Geology and Physical Geography, which may be said to have been the subjects of his predilection
during the last twenty years of his life. Nor were these labours of the closet merely; he was far more intimately versed in the
mineral structure of the earth, from observation, than any except a few professed geologists; and he exceeded them all in the
ability^with which he expounded and maintained the striking doctrines of the Huttonian theory. Though professedly the “ illus¬
trator of the principles specifically but obscurely laid down by Hutton, he certainly added much of his own. There is no rea¬
son to doubt that Playfair first apprehended the moving power of glaciers as geological agents in modifying the surface of Alpine
countries, a matter which has of late been so earnestly discussed by the ablest geologists.
\\ hat adds to the singularity of the combination of tastes and talents to which I have referred is, that he appears to have
had the slightest possible taste for that art of experiment which he eloquently advocated, with Bacon, as the grand distinction of
modern science. I may be wrong in stating it broadly, but I do not now recollect a single experimental novelty, much less dis¬
covery, which we owe to Playfair, I mean in the department of Natural Philosophy; for we cannot include barometrical mea¬
surements under this head, of which, indeed, it was the mathematical theory, and not the application to practice, which chiefly
occupied him. The same was the case in Astronomy, which, of the mechanical sciences, interested him most. In two capacities he
will be remembered,—first, as the able, eloquent, and generally impartial and accurate Historian of Science; secondly, as the
promoter, to so great a degree as to be considered a second founder, of modern Dynamical Geblogy. He was much beloved in
private life, and was singularly free from the tendency to carping criticism and personal prejudices sometimes, unfortunately,
found in men of letters. He was the intimate associate of Jeffrey and the other founders of the Edinburgh Review.
His character has been drawn in three words by Sir James Mackintosh, and as happily contrasted with that of his illustrious
friend :— . . . . Playfair and Jeffrey; the first a person very remarkable for understanding, calmness, and simplicity, the
second more lively, fertile, and brilliant than any Scotchman of letters ” {Life of Sir James Mackintosh, ii. 251).
Whewell s History and Philosophy of the Inductive Sciences, 5 vols. 8vo. 2 Mill’s Logic, 2 vols. 8vo.
(20.)
Pure ma¬
thematics
—their
progress
and tech¬
nicality.
804
MATHEMATICAL AND PHYSICAL SCIENCE. [Diss. YI.
before him and since by Galileo, Newton, and their established, by the genius of Euler and Lagrange, on
, an impregnable basis.
^With'regard to Pure Mathematics, and their pro- The intense, and praiseworthy, and successful (21-)
eress during the last seventy years, to the difficulty labours of their followers have been, then, chiefly de-
arising from the extent to which the review must have voted to the occupation of the fields of conquest thus
enlarged this Essay and the enormous and dispropor- summarily opened; or, rather, to storming, one by one,
tionate labour it must have cost (a labour far greater fortresses still unreduced, after the main resisting army
to the present writer than to one by taste and habit had been first routed in the open field. To quit meta-
more addicted to the study of merely abstract Ana- phor, the efforts of mathematicians have for many
Ivsis) a conclusive argument against their systematic years been chiefly applied to rendering possible the
introduction into this historical sketch is to be found solution of problems involving quantities which ac-
in the very nature of these modern improvements, tually occurred in the course of the rapid simulta-
All sciences but especially the abstract sciences— neous advances of physical science. They are in a
tend to become more intensely technical the farther manner inseparable from the branches of physics in
they are pursued. These especially are incapable of aid of which they were originally called forth, and
popular treatment, although in their applications to will therefore be most properly noticed, however
physical science they occasionally admit of it in a briefly, in the chapters of this Dissertation where
very remarkable manner. The progress of analysis their application is considered. Some farther obser-
cannot be even enunciated or expressed but in the vations on this subject will be found in the imme-
language of analysis, and the History becomes almost diately succeeding section of the present Essay,
a Treatise, or, if not a Treatise, something nearly as .
technical. It is partly for this reason that the his- In reviewing the progress of science—physical (22.)
toryof the Pure Mathematics has so seldom been science in particular—during the last seventy or
even attempted to be written.1 Mathematicians have, eighty years, I have thought it advisable not tosico_Mathe.
since the time of D’Alembert, been noted for being subdivide the subjects too minutely, and, following matical
more ready themselves to publish than to become nearly the arrangements of Dr Whewell’s excellentSciences-
acquainted with what others have done; and one con- treatise, already quoted,31 shall treat, m successive
sequence of this has been the formation of a mathe- chapters, of Analytical Mechanics including Physical
matical literature, able, profound, and original, but Astronomy as their loftiest and most successful ap-
cumbrous, fragmentary, and full of repetitions.2 plication; of Astronomy as a science of observation ;
Besides, the seventeenth century had attained the of Mechanics, with reference to the intimate consti-
vantage-ground of those grand and striking im- tution of matter, including Hydrodynamics, Acous-
provements in methods to which no subsequent im- tics, and Civil Engineering; of Optics, or Light; of
provements, however real and ingenious, can by Heat, including the Daltonian theory of the gases
possibility compare. We shall never have inventions and chemical elements ; and, finally, of the large and
comparable, in universality and importance, to the comprehensive science of Electro-magnetism, includ-
application5 of Algebra to Geometry, and the dis- ing ordinary and Voltaic Electricity, Terrestrial Mag-
covery of Fluxions. These also admit of being at netism, and Diamagnetism the discovery of Dr Fa-
least partly explained in language not obtrusively raday. . „.
technical, and have been so explained by the facile pen The arrangement of the chapters is thus strictly ^ W
of Playfair; but all subsequent discoveries have been Methodical; but in the subdivision into sections, lment{)artly
but enlargements and improvements on these pri- have allowed the Biographical principle to predomi- methodical,
mary and distinguishing ones; and before the date nate, thus giving as much as possible a historical partly bio-
at which our present discourse properly opens, even character to the whole, and endeavouring to intro- S f
the larger generalizations of Newton’s fertile calcu- duce the reader to the intellectual acquaintance of
lus—the method, namely, of Variations, and the in- the eminent men who are selected for notice on the
tegration of partial differential equations, had been principles which have been already detailed. In some
1 Specimens of what a history of pure mathematics would he, and must he, are to he found in the able Reports of Dr
Peacock and Mr Leslie Ellis, in the Transactions of the British Association for 1833 and for 1846. A glance at these profound
and very technical essays will show the impossihility of a popular mode of treatment, whilst the difficulty and labour o pro
ducing such summaries may be argued from their exceeding rarity in this or any other language. _ _ ,
2 The celebrated Lagrange, in his later years, contrasting the mathematical works of his own generation with those w ic e
studied when a youth, is said to have observed :—“ I pity the young mathematicians who have so many theories to wade throug .
If I were to begin, I would not study ; these large quartos frighten me too much.”-—(Thomson’s Annals, vol. iv.) . And it is sta e
that whilst his own most abstruse investigations were conducted in Paris, he kept the perusal of M. Gauss s writings for t e ran
quil retirement of the country,—a distinction intelligible enough between the intense effort of invention more than sustaine . y
the vis tnVa of genius which prompts it, and the strain required to master the dead weight of reasoning imposed upon t e min
by the discoveries of another. Dr Young, in his biography of Lagrange, observes upon the voluminous mathematical litera ure
of his time, that “ unless something be done to check the useless accumulation of weighty materials, the fabric of science wi sm
in a few ages under its own insupportable bulk.” The fact is that a large proportion of the mathematical writings o even
eminent authors are in a few years forgotten, or only casually consulted on some matter of history.
3 History and Philosophy of the Inductive Sciences,
Chap. I., § 2.]
MATHEMATICS—PHYSICS—MECHANICAL ARTS.
805
instances, however, it has been necessary to introduce
the same individual into two or three different sec¬
tions, and even into different chapters, when his pur¬
suits have been in very various branches of science.
This has been avoided, however, as much as possible,
and a sacrifice has occasionally been made of the
methodical order of the subjects, so as to combine in
one view all that has made an eminent philosopher
illustrious. Such little sacrifices of arrangement are
incidental to the way of treating the whole subject;
and it may be hoped that its practical advantages,
in the eye of the general reader, will be found to
compensate for its defects as they may appear to the
more rigorous student. For the sake of the latter
especially, a short but comprehensive index of Names
and Terms is prefixed, by which, I believe, it will be
easy to trace all that is said of any one person or
subject in any of the chapters.1
2. On the relations between Mathematics and Natural Philosophy, and between the latter and
the Mechanical Arts.
(24.) The object of this Dissertation has little in com-
Connection mon with an attempt formally to subdivide human
matics " knowledge into compartments, and to assign their
physics,and boundaries with metaphysical exactness. It is chiefly
mechanical in their practical bearing on one another that they
must be considered. If one science, like Mathe¬
matics, furnish the only sure step towards the un¬
derstanding or the enlargement of another, as Astro¬
nomy or Optics, a practical link is constructed be¬
tween them, which renders the progress of the one
not independent of the progress of the other. The
intimate and reciprocal connection thus subsisting
between Mathematics and Physics is to be found in
almost an equal degree between Pure Physics and the
Mechanical Arts, of which we take Civil Engineer¬
ing to represent the department most cognate to
that of Natural Philosophy, of which this Disserta¬
tion more especially treats.
(25.) The history of the last seventy or eighty years
Boundaries ^forces this conclusion. The boundaries of Science
andArtun-an<^ are as ^indefinable as those of “fact” and
defined. “ theory,” or those which separate the kingdoms of
nature from one another. There are arts which can
hardly be called scientific, and there are others which
have contributed more to the original stock of know¬
ledge than they ever drew from it. These last are
like the shoots of those tropical plants which at first
are mere buds upon the trunk, and are nourished
solely by its juices, but which, when they reach the
ground, plant themselves there, and become not only
the props and stays of the parent stem, but supply it
from an ever-increasing area with the sap which they
originally borrowed.
(26.) The more closely we examine the subject, the more
are we satisfied that it is impossible to teach science
rightly without teaching its applications; and that
the limit to which we are to do so is a limit depend¬
ing solely on the judgment of the teacher, and on
the special purpose of the lesson. But the progress
of science is a lesson learnt from the great book of
experience; and if we are to feel the force of its
teachings, we must consult, not one, but many of its
pages. Looking to the history of science since 1750,
but especially during the present century, it is quite
impossible not to admit how large a share the sciences
of application have had in moulding the direction of
men’s thoughts and speculations, and in enabling,
nay, compelling them to realize certain abstract no¬
tions far from easy of conception. Instances of this
are to be found in the force of percussion, the co¬
existence of vibrations in air and other substances,
and such notions of body as we derive from practical
efforts of continually-increasing boldness to extend
the scale of our constructions.
The analogy of the relation between Mathematics (27.)
and Physics, and of the latter to civil Engineering, is Practical
so close that the three subjects might almost be re- ofth^last
presented as three terms of a continued proportion. 100 years.
What the second is to the first may be affirmed of
the third relatively to the second. Physics may
exist, at least to a limited extent, without a mathe¬
matical basis, as the art of construction long preceded
a knowledge of the principles on which it is founded.
But as knowledge advances it extends in both
directions towards speculation and towards practical
applications, but most towards the applications. This
Bacon well understood, and he has consistently main¬
tained, that knowledge, to be profitable to its cultiva¬
tors, must also be fruitful to mankind. And all the
history of science since Bacon’s day has read this
1 I have borrowed but sparingly, in the following pages, from the existing compilations on the history of science. Indeed,
a writer who intends to make a subject his own by a well-considered, fundamental plan of treating it, will use such works prin¬
cipally as a guide to his own further inquiries, and to assist him in selecting the topics worthy of fullest discussion. In this
respect Dr Whewell’s excellent writings, already cited, have been of great use to me; and in the particular department of
Astronomy, I have often referred to Mr Grant’s valuable History of that science, as well as to the writings of Delamhre, and
the very elaborate Historical Essay by M. Gautier, on the problem of the Three Bodies, which is not, I think, noticed by
Mr Grant, but which contains a most elaborate history of the researches of Lagrange and Laplace. In optics, I have consulted
the systematic treatises of Dr Young, Sir D. Brewster, Sir J. Herschel, Dr Lloyd, M. Moigno, and M. lladicke; and so of other
subjects. Gehler’s Physikalisches Worterbuch, Fechner’s Repertorium, and that of Dove, afford a vast amount of historical infor¬
mation. The Transactions and Proceedings of the various societies, British and Foreign, have of course furnished a great part
of my information. Such strictly biographical details as I have made use of, have in general been very carefully taken from
the best accessible authority.
806
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
lesson more and more loudly in the ears of manldnd.
The era of Newton and Leibnitz was grandly distin¬
guished by the continually increasing applications of
mathematics to physics, whereof Newton was the great
teacher; the century 1750-1850, whilst profiting
by the lessons of the past, has added almost a new
one in the eminently practical character of its science,
and in the no less scientific character of its practice.
The result of these gradual modifications of human
knowledge has not been in the slightest degree in¬
jurious to the real progress of the more abstract in-
Notinju- gredient of the mixed sciences. Did mathematics
riousto ever flourish more vigorously than under Newton 1
science* has pure physical science had greater triumphs than
in the era of Volta, Watt, and Young X It was
precisely because the new application of mathematics
stimulated their growth, because abstract relations
of quantity were vivified by concrete solutions of
physical problems, that a new geometry arose.
Dynamics could hardly be said to exist as a science
without the invention of Fluxions as a language by
which its conditions and results might be expressed;
and from that time onwards, the necessities of the
natural philosopher have been the prime sources of
inspiration to the geometer, while the subjects have
become so blended that a mere discoverer in mathe¬
matics has become a singularity. It would be hardly
possible to point out any mathematician of the
highest class since Newton, or but a few of the second
class, who have not contributed almost as much to
physical science as they have to analysis. Of purely
mathematical discoveries, the great majority have
been called forth by the immediate necessity arising
from some problem requiring solution in astronomy,
mechanics, optics, or heat. Lagrange’s method of
Variations of arbitrary Constants in Integration, the
artifices for the computation of attractions by Laplace’s
coefficients ; the introduction of the method of fac¬
torials by Kramp in his solution of the problem of
refraction, and numberless improvements in the
Theory of Definite Integrals by Fourier and his suc¬
cessors, sufficiently warrant the statement, and show
how richly the physical sciences have repaid to the
purely mathematical ones the debt which they oi'igi-
nally owed. One other conclusion may be drawn
from these and parallel facts. It is that the com¬
binations arising out of external phenomena are more
suggestive of the possible relations of number and
quantity than is the most unlimited stretch of fancy
and imagination; and I believe it will be conceded
that, with few exceptions, theorems of the greatest
value and beauty have been more frequently dis¬
covered during the attempt to solve some physical
or at least geometrical problem, than in compre¬
hensive yet indefinite attempts to generalize the re¬
lations of abstract magnitude.
(28.) These views are strikingly confirmed by the his¬
torical fact of the paucity of pare mathematicians, The pure
and of distinct mathematical treatises of a strictly
original character in an age distinguished by the
diffusion of mathematical knowledge, and in countries
(like France) most celebrated for its triumphs. There
are not, perhaps, much more than half a dozen
really great mathematicians of the last seventy years,
who have not left treatises more numerous and more
distinguished on physical science, treated mathe¬
matically, than on pure mathematics. Among the
exceptions which more immediately occur, are Monge,
Legendre, and Abel. And of distinct treatises, whilst
we have the Mecanique Analytique, the Mecanique
Cdleste, the Thdorie de la Chaleur, and numberless
others, containing precious mathematical develop¬
ments, in connection with the applications which
suggested them, the purely mathematical memoirs of
the same period are to be sought chiefly in the form
of detached essays, in the ponderous volumes of
Academical Transactions.
One point in the History of Mathematics has espe- (29.)
cial interest for the English reader, and as such may
be touched upon here with reference to the progress country.13
of science for the last three quarters of a century.
The national pride of England in the triumphs of
Newton impelled her ablest mathematicians to at¬
tempt to carry forward the synthetic methods which
he had chiefly used, at least in his published works,
to the more arduous and intricate questions of Me¬
chanics and Astronomy which presented themselves
for solution in the course of the 18th century. Mac-
laurin was almost the last Englishman of that period
whose mathematical writings came into direct com¬
petition with the rising schools of Germany and
France. The labours of Matthew Stewart, and
Simpson were mostly geometrical; those of Landen
and Waring, though profound, created little general
impression; and, gradually, the extent and difficulty
of the foreign mathematics, increased by the use of the
Leibnitzian notation of differentials which was ab¬
solutely unfamiliar in England, deterred almost every
one even from perusing the writings of Clairaut and
D’Alembert, Lagrange and Laplace. Of the conti¬
nental mathematicians, Euler was probably the best
known, owing to the lucidity of his writings and
their eminently practical tendencies. Some idea may
be formed of the negation of mathematical talent in
Britain during the later portion of the last century,
when we find D’Alembert declaring, in 1769, that if
an Englishman is to be elected one of the eight
foreign associates of the Academy of Sciences, he
will vote for Earl Stanhope as the best mathemati¬
cian there, as he believes, not having read any of
his works ! If the choice was to be free, he should
prefer M. de Lagrange ! I1 A more cutting, though
unintentional satire on the state of Mathematics in
this country could not have been written.
1 Letters of eminent persons, addressed to David Hume, edited by Mr Barton, p. 215.
Chap. I., § 2.]
MATHEMATICS—PHYSICS—MECHANICAL AHTS.
807
(30.) The commencement of a better era originated, early
bridge'*1 2 * * * * * * *" t^ie Present century, with Woodhouse at Cambridge,
Edinburgh, and Playfair in Edinburgh, by both of whom the con-
and Dublin, tinental methods were introduced into the studies of
their respective universities ; whilst Ivory, a native of
Scotland, Avas the first to challenge, by his writings, a
place in the list of great living mathematicians. The
systematic form of the Mecanique Celeste rendered the
subject more accessible than were the countless me¬
moirs by men of the highest name, which then filled
the Tiansactions of Paris, Turin, Berlin, and StPeters-
burg. But the notation of differentials, \AThich could
alone break down the barrier between the British and
foreign mathematicians, was first introduced at Cam¬
bridge by the efforts of Sir John Herschel and Dean
Peacock about 1816, soon after which the transla¬
tion of Lacroix’s Differential Calculus, which they
superintended, came into use as an university text¬
book. From this time the Avorks of foreign mathe¬
maticians began to be more generally read, particu¬
larly the Avritings of Laplace and Poisson; and
Avithin ten or a dozen years subsequently, a few
active and undaunted men, chiefly of the Cambridge
school, such as Mr Airy and Sir John Lubbock,
grappled with the outstanding difficulties of physical
astronomy, whilst a larger number applied them¬
selves to the most difficult parts of pure analysis,
and acquired great dexterity in its use in the solu¬
tion of geometrical and mechanical problems. Such,
for example, were Mr Babbage, Mr De Morgan, Mr
Murphy, and Mr Green ; and at Dublin Sir William
R. Hamilton and Mr MacCullagh, whose names Avill
occur in other parts of this Dissertation.
(310 No neAv calculus or great general method in ana-
^nents^in" ^as resu^ted from these persevering labours,
integra- whether of British or foreign mathematicians, but
:,on- an increased facility and powder in applying the ex¬
isting resources of mathematics to the solution of
large classes of problems previously intractable, or
resolved only indirectly or by approximation. The
Integral Calculus, in particular, affords an almost
boundless field for research, and each branch of
science in succession—not only Physical Astronomy,
but Optics, Heat. Electricity, and Civil Engineering
—has offered problems of great importance, which
awaited only the skill of the pure mathematician to re¬
solve in a practical and finite form.1 Every year, and
every civilized community, contribute to these real
IUS funn^u* improvements. The principle of discontinuity, coxi"
ions.  
spicuously introduced into the doctrine of the con¬
duction of Heat in consequence of the abrupt varia¬
tion of physical circumstances at the boundary of
the conducting body, enters largely into the specula¬
tions of mathematicians of the present century; and
the doctrine of definite integrals so intimately con¬
nected with it has received a proportional extension.
Next, analytical geometry has acquired a very great Analytical
enlargement and by attention principally to symmetry seomet^y•
in the arrangement of the results, solutions other-
Avise the most intricate are obtained with facility and
directness. Of this we shall find examples in our
history of the Undulatory Theory of Light. Lastly, The Calcu-
notwithstanding the pre-eminently practical charac- lus.of Ope-
ter of the mathematics of the last age, speculative ratl0ns'
geometers and analysts have found time to discuss
the metaphysics of their respective sciences, both as
regards the foundations of the Differential Calculus
and as to the use of imaginary and other symbols in
Algebra. An almost new branch of abstract science
(though faintly foreshadoAved by Leibnitz) has come
into existence—the separation of symbols of opera¬
tion from symbols of quantity, and the treatment of the
former like ordinary algebraic magnitudes. In some
cases remarkable simplicity is thus introduced into
the solution of problems, although perhaps few ma¬
thematicians Avould choose to depend implicitly upon
the method in untried cases. Sir John Herschel and
the late Mr Gregory2 w^ere amongst the most active in¬
troducers of this new algebra, but few of the more
eminent INing British or foreign mathematicians
have failed to contribute their share to this more
metaphysical department of analysis.
I shall noAv attempt to consider more particu- (32.)
larly the reciprocal relations of pure physical science Connecti°n
and the mechanical arts. of- Physica|
Hus is evidently a very intimate one. The dis-the arts.
coAreries of pure physics (such as Astronomy, Acous- (330
tics, Magnetism), are the results of either observation
or experiment, and they consist in generalizations,
by means of which a multitude of facts are reduced
under one simple expression of a more general fact
or principle. But instruments often very compli¬
cated are necessary for observation and for experi¬
ment ; as telescopes in astronomy, organs in acoustics,
properly magnetized and suspended steel bars in
magnetism. Art is required to construct these. The
highest possible degree of science, and the utmost
1 For example the Lucasian Professor at Cambridge, Mr Stokes, has effected two previously impracticable inteorations, one
occurring in the theory of the rainbow, the other in that of railway girder bridges.
2 Mr Duncan Gregory, a promising mathematician who died 23d February 1844, at the early age of 30, was the youngest Mr Duncan
son of Dr James Gregory, the late distinguished Professor of Medicine at Edinburgh. His name deserves a passing record, not only Gregory,
from the influence he exercised on the progress of the English mathematics of his time, but as having revived the dormant charac¬
ter for this peculiar kind of talent, so long connected with the family of Gregory. He was, in fact, the lineal descendant of the
inventor of the reflecting telescope. Mr Gregory was the first editor of the Cambridge Mathematical Journal, and author of an
excellent book of Examples in the Differential and Integral Calculus, both of which have exercised a beneficial influence on the
progress of science in England. He also wrote several original memoirs on the subjects referred to in the text. Mr Leslie Ellis,
a man of congenial ability, has written a short but pleasing biography of his friend.
808
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(34.)
Great Me¬
chanical
inventions
presume a
knowledge
of physical
laws;
(35.)
and gene¬
rally an in
ductive
process.
mechanical skill, are both indispensable to make a
telescope. A telescope then, though a mechanical
invention, inasmuch as it is a deduction fiom phy¬
sical principles, not an addition to them, is j-et a
deduction so ingenious—so far from obvious so im¬
possible to be conceived accidentally or by a loose
thinker, and so easily made the instrument of innumer¬
able discoveries of the highest novelty and grandeur,
that no historian of science ever thought of omitting
the invention of the telescope, or of giving it an im¬
portance inferior to that of a discovery, containing as
it did the germ of so many discoveries. In like manner
a theory of optics might be written in which a tele¬
scope need never be mentioned; but would not the
pedantry of such a work be obvious, or would any
reasonable person wish to learn science after such a
fashion ?
The clear co-ordination of the parts of an invention
towards the attainment of a given result, with a due
regard to natural laws, and the properties of the sub¬
stances used, constitutes the merit of the invention;
and this merit may be irrespective of the precise im¬
portance of the end of the invention, which may be
intended to promote science, or commerce, or con¬
venience, or even to satisfy mere curiosity. A tele¬
scope would have been a telescope still, could we have
imagined it invented with no other object than a deer¬
stalker’s sport; and so contrivances which in their ori¬
gin and application seem remote from scientific uses,
constitute nevertheless real steps in the progress of
knowledge. The steam-engine is one striking ex¬
ample. Originally devised with an exclusively com¬
mercial object—the extrication of the Cornish mines
from subterranean water, it became in the hands of
Watt, first an instrument for experiments on the re¬
lation of heat to matter; next, in its improved form,
a beautiful exemplification of these laws, and an en¬
during monument of the sagacity and skill of its
author, as well as the most important inorganic
agent which exists in modifying the social condition
of the entire globe. Finally, to illustrate the posi¬
tion from which we started, it becomes the instru¬
ment of fresh discoveries. This very engine has a
theory to be worked out, probably unimagined even
by its sagacious author—its operation as an agent for
obtaining power from matter by the application of
heat, is shown to be in all probability a single case of
a more general law, including all kinds of machines
and all sorts of matter; and this more general theory
of heat as a motive power leads, once more, to new
practical deductions, to the conditions under which
such machines may be most usefully constructed and
employed.1
Every instrument, every construction, which is
founded on a theory, and in which a certain compli¬
cation of conditions is required to produce a certain
result; a telescope, for example, or a steam-engine,
or a bridge, is, in the first instance at least, an ex¬
periment. Few inventions are so simple and straight¬
forward in their plan, are so independent of the seem¬
ingly capricious behaviour of matter under untried
circumstances, or depend so entirely on physical laws
thoroughly understood, that the inventor can await,
without the pang—at least of impatience—if not of
anxiety, the moment of the realization, by actual
trial, of his hopes and his calculations. We can all
readily imagine the throb of anxiety with which
Galileo pointed his glasses for the first time to the
moon—with which Watt saw the cylinder of his As in
model exhausted, and the piston descend under the ^
action of his separate condenser—and Stephenson, gine
the stupendous iron tube at Conway resting for the
first time straight as a ramrod on its two piers—
these are moments of anxiety and of triumph, which
place the inventor of a machine and the architect of
a structure on a par with the discoverer of a planet,
or with the author of a theory. “ Whenever an ori¬
ginal mind produces new combinations of thought and
feeling,” says Sir James Mackintosh, with equal im¬
partiality and truth, “ whether its means be words or
colours, or marble or sound, or command over the
mighty agents of nature; whether the result be an
epic poem, or a statue, or a steam-engine, we must
equally reverence those transcendent faculties to which
we give the name of genius.”2 It is almost needless
to add the caution, that such praise is only applicable
when the invention is such as to call forth the qua¬
lities which distinguish the Philosopher. It is not
the mere command over the agents of nature which
challenges our admiration, it is the foresight, the
patience, the conceptive faculty, the clear-sighted
and confident anticipations of what will be the re¬
sults of natural laws acting in given circumstances,
these circumstances being in some essential particu¬
lars new. Merely to adopt known contrivances,
where experience has already anticipated the result,
may exercise judgment, but hardly genius; and to
make contrivances in which the result depends rather
upon laws of geometry than of physics, hardly come
within the scope of these remarks.
Watt’s Parallel Motion, perhaps the most inge- (36.)
nious of his inventions, would not have made a great
reputation; nor does the endless variety of machines
used in the arts, as in spinning, printing, and paper¬
making, stand higher. It is when the inventor
places Matter in new relations to Force, or derives
power from new sources, or teaches Light or Electri¬
city to act under new conditions, that he becomes
really a Mechanical Philosopher.
It is not given to man to endue matter with new ^(3^0
properties, or to prescribe the laws under which his of ^
inventions are to take effect. A new motive power,
1 See Carnot, Puissance Motrice du Feu, and the writings of M. Clapeyron, Professor W. Thomson, &C.
2 Speech at a meeting for erecting a monument to Watt, in Arago s Eloge of Watt.
Chap. II., § 1.]
PHYSICAL ASTRONOMY—LAGRANGE.
809
a new form of construction, are experiments on the
resources of nature under new conditions.
Solutions of ^act’ even comParatively simple cases, we
mechanical cannot set forces to act on matter, or dispose mat-
as of ma- ter so as to resist force, without doing not only what
^robfenm1 We intend to do’ also a great deal more. Man
sometimes may Pu^ Powers in motion which he is unable to
manifold, control; and whilst he calculates confidently upon
the effects of such and such dispositions of force or
resistance, he may overlook consequences equally
necessary, because resulting from laws of nature
which are either unknown to him, or the magnitude
of which he had overlooked, in considering those only
which he required. A complicated mechanical con¬
trivance may be compared to the mathematical solu¬
tion of a problem. It represents commonly a great
deal more than is meant to he derived from it. It
may represent several distinct results, some possible,
some impossible, and of the former only one, it may
be, congruous to the real conditions of the problem
proposed. In mechanics, the laws of nature are
as impatient of control as the laws of quantity in
geometry, and the engineer may find, too late, that
nature has solved his problem differently from what
he expected. But even when successful, it is to he
presumed that his own contrivance contains within
it results unforeseen by himself. If he is wise he
will become a student in his own workshop. The
material contrivances are indeed his own, but the
powers which they awaken or distribute are beyond
his control. Even if his reading of the equation be
strictly correct, there may remain in the backgrouud
others no less important.
The considerations here imperfectly laid before
the reader are intended to justify the introduction of
certain practical topics into the present Dissertation,
which, though many readers will see their insertion
without surprise, or would have been sorry to find
them omitted, others possibly may think more or
less independent of, and separable from a scheme
already sufficiently extensive and intricate, if con¬
fined to mere subjects of scientific doctrine, to the
exclusion of its applications. My chief reason for
including such subjects as the steam-engine, the
strength of materials and some great examples of
(39.)
construction, and the electric telegraph, is that
these important practical improvements are both
historically and logically interwoven with the pro¬
gress of pure or abstract physics. They have be¬
sides impressed upon the character of scientific dis¬
covery of the last hundred years a peculiar stamp
which it would have been absurd to ignore while
endeavouring, within a moderate compass, and in the
plainest language, to convey a vivid though compre¬
hensive sketch of the advancement of Natural Philo¬
sophy during this and the preceding, or rather two
preceding generations.
It is not to he imagined that the difficulty of the (40.)
problems which occupy the speculative philosopher, Lessons of
or the comprehensiveness of mind required for their ordinary
solution, diminishes in any degree as we descendeXperienCe*
from the regions of pure science to the walks of every¬
day life—from the vast periods and majestic motions
which astronomy enables us to explain and predict,
to the common details of the workshop and the rail¬
way. In fact, the former are to he regarded as the
simpler investigations, whilst our terrestrial agents
have their effects modified by the diversified states of
aggregation and various mechanical properties of mat¬
ter, and by the numerous modifications of force arising
from heat, electricity, or magnetism, to which it may
be exposed. We have as yet made but an insignificant
advance towards that completer system of Natural
Philosophy of which Newton’s will form but one
section, in which all the properties of matter and
their consequences shall be as well understood as the
particular property of gravity is at present. Many of
these are to be learned by daily observation of the
effects which occur in the ordinary progress of civi¬
lization amongst us. We are continually perform¬
ing experiments on a great scale and on purely com¬
mercial principles, which no individual philosopher
or merely scientific society could have ventured to
attempt. And in the midst of these appeals to
experience, unexpected results are frequently occur¬
ring which send us back once more to the study of
first principles, which, indeed, while they confound
the empiric, do but establish the reputation of the
philosophic engineer, who seldom fails to turn them
to good account, both in his theory and practice.
CHAPTER II.
PHYSICAL ASTRONOMY AND ANALYTICAL MECHANICS.
§ 1. Lagrange.—Variation of Parameters—Application to Physical Astronomy. The Stability
of the Planetary System ; Laplace ; Poisson. Moon’s Libration.
Lagrange. The Period of Lagrange’s most celebrated labours Dissertation, it might have been excusable, with so
extends so far back into the preceding century, that great a mass of matter before us, to have passed
having been already mentioned in Sir John Leslie’s them over without farther notice. But they are so
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
810
intimately connected with the most salient points of Amongst the former we reckon the method of the (44.)
the history of physical astronomy, down even to the variation of parameters, expounded to a certain point Variation
present time and are so interwoven with the disco- by Euler, thoughts in many other cases, his results °erP*rarae*
veries of Laplace, and represent altogether so much were vitiated by the haste and inaccuracy of his cal-
of the substantive character of the progress of the culations. That Lagrange borrowed the idea from
age that I have thought it necessary to devote a Euler cannot admit of a doubt, any more than that
small space to the recital of a few of the most pro- he was indebted to him for the principles of the Oal-
minent of them, having regard to the intellectual cuius of Variations. Lagrange, with customary truth-
portraiture of the man as one of the most pre-emi- fulness, even to his latest days, always spoke of Euler
nent and successful reasoners of his class who have as his best instructor and model, and as the chief
ever done honour to their race. I shall repeat as of modern mathematicians, Newton only excepted,
little as possible what has been said elsewhere, and We know that he so regarded him in the case of the
confine myself to only two or three topics. calculus of variations which he studied in Euler’s
(42.) Joseph Louis Lagrange was born at Turin in 1736; “ Methodus inveniendi lineas curyas, &c.,” during
His birth he died at Paris 10th April 1813. His first paper the first two years of his application to the higher
and educa-wag written at the age of 17 or 18, and his end was mathematics whilst Euler, with equal candour,
tlon’ accelerated by the unremitting ardour of his labours acknowledged the transcendent genius of the rising
at the age of 77. He was consequently an original geometer, forcing its way where he himself had
author during sixty years ; and for the greater part of failed.
his contem- this period he, togetherwith Laplace, monopolized the The method of the Variation of the arbitrary con- (45.)
poraries. greatest discoveries connected with analysis and phy- slants or Parameters, though it may be regarded m
sical astronomy, and exercised an almost undisputed one point of view as a merely analytical artifice for
authority in the more recondite sciences. Euler, effecting integrations, is in reality a conception purely
Lagrange, and Laplace, by a singular coincidence, geometrical, first introduced by Newton2 under the
lived to the respective ages of 90, 77, and 79, and name of “ revolving orbits,” and applied by him to
all retained their activity nearly to the last. They the explication of the conception (to use a recently
produced, by the continuity and friendly rivalry of introduced phrase) ofthe lunar inequalities. Neither
their labours, carried to an extent in each case which the moon nor any planet really describes a mathema-
only astonishing physical vigour united to astonish- tical ellipse (in consequence of the mutual perturba-
ing mental aptitude could have produced, during tions ofthe heavenly bodies). They describe curves of
almost a century, an impression on the progress of double curvature in space, of which we could form
science altogether remarkable. This coincidence no intelligible idea, except by referring them to the
was .the more happy, because physical astronomy very approximate type of the ellipse, of which the
was exactly in that predicament when nothing less eccentricity, line of apsides, inclination, &c., are con-
than such a combination of intelligence and intensity tinually varying, not only from one revolution to
of application systematically urged, could have car- another, but throughout every part of a revolution,
ried Newton’s theory through the difficulties which This representation is not only convenient, but
at that time beset it—difficulties which left the IJrin~ strictly accurate. At each instant the moon or
cipia for so many years alone, and far in advance of planet is describing a portion of an ellipse, which
the general intelligence ofthe age. may be called the instantaneous ellipse, and which Instantane-
(43.) The pregnant suggestions of Euler were developed may be defined as the particular ellipse which the0,115 e P
Euler and and applied by Lagrange, and the triumphs of La- body would go on to describe if it were at that
Laplace, grange—nay, even his occasional failures—were the instant freed from all perturbation, and allowed to
immediate precursors of some of Laplace’s happiest complete a revolution under the single influence of
efforts. its acquired motion and the central force. To take
Lagrange’s 1 The following is a list of the hooks he then read, taken from a paper probably little known, which appeared soon after the
early death of Lagrange in the Moniteur newspaper, and which was translated in Thomson’s Annals of Philosophy, voL n. e
studies. first read Euclid’s Elements, Clairaut’s Algebra; then, in less than two years, and in the following order, Agnesis na y-
tical Institutions, Euler’s Analysis of Infinites, John Bernouilli’s Lectures, Euler’s Mechanics, the two first books of i ew on s
Principia, D’Alembert’s Dynamics, and Bougainville’s Integral Calculus, Euler’s Differential Calculus and Methodus Invenien i
—a pretty course of mathematical reading for a youth between 17 and 19. _
From the same paper we abridge a few practical directions given by Lagrange for the study of mathematics, whic , i
tolerably obvious, are interesting from the extraordinary genius of the man, and from his singular reticence on ^subjects o a
personal nature. “ I never,” he said, “ studied more than one book at a time ; if good, I read it to the end. ‘ I did no
nerplex myself with difficulties, but returned to them twenty times if necessary. This failing ,1 examined another author.
considered reading large treatises of pure analysis quite useless. We ought to devote our time and labour chiefly to the app ica
tions.” Thus he read Euler’s Mechanics when he had acquired a very slight knowledge of the differential and)ntegral calcu us.
“ I always read with my pen in my hand, developing the calculations, and exercising myself on the questions.”
“From the very beginning of my career, I endeavoured to make myself master of certain subjects, that I might have an
opportunity of inventing improvements; and I always, as far as possible, made theories to myself of the essential points, in 01 ei
to fix them more completely in my mind, to render them my own, and to accustom myself to composition.” “ Finally, I every
day assigned myself a task for the next. I learned this custom from the King of Prussia.”
2 This Lagrange himself points out in his Mecanique Analytique.
Chap. IL, § 1.]
PHYSICAL ASTRONOMY—LAGRANGE.
811
a single example; the planet Uranus has not yet
completed one revolution since the time of its disco¬
very in 1781, yet its observed path differed so much
from a true elliptic arc (even when we allow for the
perturbation of Jupiter and Saturn), that the orbit
which satisfied the observations from 1781 to 1800
would not satisfy those from 1800 to 1820; and
since 1820 a new orbit had to he computed for every
few years, so great were the variations of the instant¬
aneous from any permanent ellipse. These varia¬
tions led to the discovery of the planet Neptune.
(46.) To adapt the notion of the perpetual variation of
theory*11 ^ elliptic elements to analytical calculation, and to
ascribe to each planet its influence in perturbing the
elliptic motion of the others, was the great problem
mainly solved by Lagrange. In the planetary theory,
where the perturbations are all very small, on account
of the excessive preponderance of the mass of the
sun, the motion of each planet may be considered as
under the separate disturbing influence of every
other, and the whole perturbation is the sum of the
separate perturbations.
(47.) Now, these perturbations of elliptic motion may
and'secular ke into two great classes, which Lagrange
inequali- 1782, included in a common analysis, which
ties. expressed the disturbed elements of planetary motion
by two sets of terms : those which include the rela¬
tive positions (or configuration) of the disturbing and
disturbed planets being the one set, and those which
included only the masses and elements being the
other. The former are called periodic, the latter
secular inequalities. The distinction is important,
since, after a sufficiently long time, two planets (sup¬
pose the Earth and Mars) will have been presented
to one another in space in every conceivable posi¬
tion of which, by the form and position of their or¬
bits, they are susceptible, a like recurrence of confi¬
gurations will recommence, and like perturbations
will result. Such influences, though running through
long periods, will be evidently recurring. But there
is another class of disturbances, which may in thought
be entirely separated from the former, being the ulti¬
mate or average effect of the influence of one planet
on another, arising, not from the position of the pla¬
nets in their orbits at any one time, but from the po¬
sition of the orbits themselves. Thus in a single
revolution (and on account of the independent excen-
tricities of the orbits during many successive revo¬
lutions) of Mars and the Earth, the attraction of the
former on the latter sometimes conspires with the
sun’s attraction, sometimes opposes it, sometimes
urges the Earth forward in its path, and sometimes
pulls it back, producing numerous periodic inequali¬
ties ; but it is quite evident that, in the long run,
the attraction of Mars on the Earth tends to pull it
away from the sun, and to diminish the effect of the
solar attraction—in fact, to increase the length of
our year; and that this influence will be precisely
the same if we take the average of a great many re¬
volutions now, and compare them with a similar ave¬
rage hereafter, provided that the orbits undergo no
permanent change. This, therefore, though not strictly
an inequality, because the length of the year is per¬
manently changed by it, shows an average effect in¬
dependent of the configuration of the planets. An
example of a true secular inequality is the revolution
of the line of apsides or major axis of any orbit, by
the influence of the disturbing forces of the planets,
whether interior or exterior to the one considered.
Few of the secular inequalities have been detected by change of
observation throughout the entire records of Astro- apsides and
nomy. It is known, however, that the apsides of the ef centri-
planetary orbits (at least in the case of the oldClties’
planets) all progress, with the exception of those of
Venus, which retrograde, and that the inclination of
all is at present diminishing. The excentricity of the
Earth’s orbit is decreasing at the rate of 40 miles per
annum. The exclusive dependence of the secular ine¬
qualities on the orbits, not on the places of the planets,
may be well illustrated by a method actually employed
by Gauss for computing them (though it does not
appear to be attended by any special advantage).
He conceives the orbit of the disturbing planet to be
strewed with attractive matter, whose thickness at
any point is inversely as the planet’s velocity there,
or directly as the time of its sojourn in any small
length of the orbit.
The method of variations of the elements is evidently ''
most applicable to the determination of Secular Per¬
turbations ; for to compute by means of it the ordi¬
nary inequalities involves an apparently unnecessary
labour. The place of a planet is completely determined
by three co-ordinates—its longitude, latitude, and
radius vector; whilst the elements of the orbit are six in
number, and when found, a further calculation must
be made to find the co-ordinates of position. The
more direct method of deducing the co-ordinates at
once from the conditions of perturbation, was gene¬
rally followed until 1808, when Lagrange and
Laplace almost simultaneously devised methods of
using the variation of the elements with directness
and despatch in the calculation of Planetary Pertur¬
bations. In the estimation of the second and higher
orders of disturbance, it has even the advantage in
these respects over the other method.
Stability and Permanence of the Solar System.— gtaiili? of
After it had been clearly recognised, principally by the solar
the labours of Lagrange, that the elements of the pla- system,
netary orbits are in a condition of perpetual change,
it came to be a most interesting question how far
such variations were likely to be continuous, and ulti¬
mately so great as to modify altogether the forms of
the orbits, and even endanger the separate existence
of the planets. This is a question which has excited
a very general, as well as scientific interest. It is
evident that the variations of the different elements
are not all equally important in affecting the perma¬
nence of an orbit. The five properly orbital ele-
812
[Diss. VI.
5
MATHEMATICAL AND PHYSICAL SCIENCE.
merits (the sixth being the longitude of the planet on
its orbit at a given time) may conveniently he con¬
sidered thus : 1st, the major axis, which, for one and
the same system, involves the periodic time or mean
motion; 2d, the excentricity and position of the line of
apsides; 3d, the inclination and position of the line of
nodes. Of these, the stability primarily depends upon
the first. If the major axis and mean period increase
or diminish without limit, the planets will diverge
into infinite space, or rush after myriads of ages to
utter annihilation in the burning embrace of the sun.
The latter alternative was the popular belief about
the middle of last century, and was maintained by
the grave authority of Euler; whilst Darwin, in his
florid but picturesque language, described the order
and beauty of the planetary system as hut a little
more permanent than the glowing ornaments of the
gay parterre.1 * * * * The principal reason for this conclu¬
sion, and its refutation, will be mentioned in the next
section.
(51.) The first person who perceived the probable sta-
Laplace’s p^j^y of the major axes and mean motions was not
S*covery!6 * * * * Lagrange hut Laplace, who, in a paper published in
1773, gave a demonstration, the sufficiency of which
has not been doubted, that the major axes are in¬
variable, so far as the influence of the principal
terms of the disturbances are concerned, that is as
far as terms containing the cubes of the excentrici-
ties inclusive, and the first powers of the perturbing
masses. Nor does Laplace appear to have doubted
that the mutual distinction of the terms, including
secular changes, was not accidental, but would ex¬
tend also to the farther approximations. Lagrange,
however, in a celebrated though short memoir of
1776, demonstrated the truth of the conclusion for
the higher powers of quantities contained in the per¬
turbations of the first order, and that by methods
peculiarly comprehensive and elegant, which he far¬
ther extended in 1781 to the other five orbital ele¬
ments, showing the periodicity within certain narrow
limits of the excentricity and inclination, the only
elements, except the major axis, whose variations
menace the stability of the system. Yet it is quite
impossible to separate completely the names of La¬
grange and Laplace in the effectual demonstration of
this important truth, the former as frequently in¬
dicating the means of overcoming the more purely
mathematical difficulties, as the latter was suggestive
and far-sighted in anticipating their application to
the peculiarities of our system.
Laplace discovered (1784) two remarkable theo- (52.)
rems which limit the whole amount of the excentri-
cities and inclinations of the orbits of the planetary t;es ancj in_
system, showing that if once small, they must ever clinations
remain so; and, in particular, that the most massive ^ P1^-^
planets of the system (Jupiter and Saturn) must also taiy 01 lts'
undergo the most trifling variation in these respects.
In the case of the small planets between Mars and
Jupiter, a wider range may occur (as indeed we prac¬
tically find to be the case), without endangering the
permanency of the whole. It also followTs that these
variations, though “ secular,” are practically 11 perio¬
dic ;” that is, that the excentricities and inclinations
oscillate about certain mean values and within ex¬
tremely narrow limits, the periods of these oscillations
being also of vast duration. Concerning such changes,
theory is our only guide. The whole duration of astro¬
nomical records can barely reveal the existence of two
or three of them, and tells us absolutely nothing of
their remoter consequences. Lagrange calculated
the superior limits of the excentricities of the larger
planets, and M. Leverrier has recently, by more ac¬
curate methods, obtained results nearly coincident.
According to him, the maximum excentricity of the
Earth’s orbit is 0-07775, the minimum 0-003314, so
that it can never be quite a circle. It is now di¬
minishing, and will continue (according to the same
geometer) to do so for 24,000 years, when it will
begin to increase. The inclinations of the Earth s
orbit to its equator, and also to a fixed plane, are
confined within definite limits which are not perhaps
very perfectly known.
The motions of the apsides and nodes of the orbits (530 f
which gradually complete the entire circumference an(j
have manifestly no tendency to affect the stability ofnodeSi
the system. The grand cycle of the Earth’s perihe¬
lion will only be completed in 110,000 years. It
coincided with the vernal equinox 4089 years before
Christ, a period (as Laplace remarks) nearly coinci¬
dent with that assigned by chronologers to the creation.
These results may be considered as among the (54.)
most astonishing with which science brings us ac-
1 “ Roll on ye stars! exult in youthful prime,
Mark with bright curves the printless steps of Time,
Rear and more near your beamy cars approach,
And lessening orbs on lessening orbs encroach;
Flowers of the sky! ye too to age must yield,
Frail as your silken sisters of the field!
Star after star from heaven’s high arch shall rush.
Suns sink on suns, and systems systems crush,
Headlong, extinct, to one dark centre fall,
And Death and Night and Chaos mingle all!
’Till o’er the wreck, emerging from the storm,
Immortal Nature lifts her changeful form,
Mounts from her funeral pyre on wings of flame,
And soars and shines, another and the same.” >
Darwin’s Botanic Garden, Canto iv., line 3b7.
Chap. II., § 2.]
PHYSICAL ASTRONOMY—LAGRANGE.
813
quainted. The range of insight which man has ac¬
quired into the past and future history of the uni¬
verse throughout periods, compared to which, the
whole existence of his species is but a span, enhances
our admiration of the reasoning power which can
attain to knowledge so high and excellent. And the
sublimity of the contemplation is increased when we
recollect that these recondite truths are all conse¬
quences of a law so simple as that of gravity. Ob¬
servation will reveal only to a late posterity the se¬
cular modifications of the planetary orbits which geo¬
metry now predicts to us. Some of the ellipses will
elongate, whilst others tend to become circles; their
planes will vary in inclination, but ultimately be
stayed within the limit which human sagacity had
predicted myriads of years before. “These,” says a
French analyst, “are the pendulums of eternity, which
beat ages whilst ours beat seconds.” And amidst
all these variations, subject to law and to impass¬
able limits, the Major Axes of the orbits preserve a
stedfast uniformity, or are subject only to transient
fluctuations; and thus permanence arises in the midst
of change, and the perfection of the system is demon¬
strated by the very nature of the disturbances which
seemed at one time inevitably to limit its duration.
It remains to add, in closing this interesting
discussion, that Lagrange himself had not quitted the
the theory! before his able disciple and follower, Poisson,
pursued the inquiry of the stability of the system,
and the permanency of the major axes particularly,
to a degree of approximation not before attempted.
He included the perturbations of the second order,
or those which arise by correcting the elements for
the disturbances first found, and including the effects
of the correction in the modification of the perturba¬
tions themselves. These also are subject to the
same laws as found by Laplace and Lagrange for
lower degrees of approximation ; and as MM. de
Pontecoulant and Leverrier have confirmed the result
(at least for all the larger planets of the system), we
may conclude it to be a truth as firmly established as
any negative fact can be, that our system is arranged
for a duration apparently indefinite ; that if the planets
cease to roll, and the sun and moon to do their
office in enlightening the world, it must be in all
(55.)
Poisson’s
addition to
probability by an interposition of Almighty power,
as direct and immediate as the creative energy by
which they were launched into space, and (our earth at
least) peopled with successive races of animated beings.1
We have, in the commencement of this section,
disclaimed the intention of entering at large upon the Lagrange’s
history of Lagrange’s discoveries. They fell more pro- oth.ef
perly under the scope of the preceding Dissertation, b '
and an able summary and enumeration of his writings
by no less competent a person than Dr Thomas Young
will be found in the alphabetical part of this Encyclo¬
paedia. I will only add, that while scarcely a topic
in physical astronomy, or in pure mathematics, failed
to receive important additions from his pen, his
memoirs on the Libration of the Moon, his solution
of several problems of Sound and vibrating strings,
and his methods of computing the perturbations of
Comets, are amongst his contributions to science,
most vividly remembered and most justly admired as
models of analytical ability. He himself is stated
to have preferred, amongst all his papers, one in the
Turin Memoirs of 1784, on the Integral Calculus.2
With reference to the Lunar Libration, Lagrange (57.)
confirmed the singular conclusion of Newton, that the Libration
moon is a spheroid, having three unequal axes, the
longest of which is always approximately directed to
the earth, and the shortest is her axis of rotation.
In consequence of this, the moon, of necessity, re¬
volves on her axis in the exact time that she circu¬
lates round the earth (supposing that at any time
these periods were nearly, though not absolutely,
coincident), and is subject (as Newton had divined)
to a species of oscillation upon her axis, owing to the
line of the earth’s attraction not always coinciding
(in consequence of the moon’s irregular motion in
longitude) with the moon’s greatest diameter. This
constitutes a 'physical libration, as inequalities in lon¬
gitude, by enabling us to see more or less of the
lunar hemisphere diametrically opposed to us, con¬
stitute an optical libration, or apparent to-and-fro
motion on her axis. In this investigation Lagrange
first used the combination of D’Alembert’s Principle
with that of Virtual Velocities, afterwards fully ex¬
panded in the Mecanique Analytique.3
Lagrange was happy in passing his days with (58.)
1 No reasonable doubt exists as to the stability of the planetary system to which our earth belongs, as it is at present consti¬
tuted. To what extent the laws of order which we observe in it might be transgressed with impunity, it is more difficult to say.
The investigations of Laplace and Lagrange assume the motion of the planets in one direction, and their moderate excentri-
cities and inclinations, as conditions of the guarantee of stability. But it does not appear by any means certain that all these
conditions are essential, and consequently the argument which has been sometimes employed, that the concurrence of many in¬
dependent circumstances were requisite to the stability of the system, is at least incomplete. Compare Laplace, SystGme du
Monde, edit. 1824, vol. ii., p. 29, and Herschel’s Outlines of Astronomy, art. (669).
2 It is No. 17 in the enumeration of his papers in the article Lagrange in the Encyclopaedia.
3 Very recently (1854), M. Hansen of Gotha, a most eminent living authority, has somewhat modified the received opinion ]yf_ Hansen
respecting the moon’s figure. He finds that the presumed ellipticity of the moon in the direction of the radius of her orbit is on the
not justified by observations, which ought to show a slight variation in her horizontal diameter when the libration presents to moon’s
us our satellite in a slightly varied aspect. And he infers from an elaborate investigation of the lunar observations, that her figUre.
centre of figure does not coincide with her centre of gravity, but lies about 31 English miles nearer to us than the latter. M.
Hansen adds that the existence of such a protuberance of the moon’s body relatively to the centre of gravity on the side which
we can alone view, would account for the apparent absence of water and air, which may abound upon the opposite side.—
Astronomical Society’s Notices, vol. xv., p. 13.
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
814
Private the tranquillity of a philosopher. He was respected
characterof an(j reWarded alike by kings and democrats—he was
Lagrange. honoured and promoted in three great states, Sar¬
dinia, France, and Prussia. Though patronized by
the despotic Frederick, and lodged in her palace by
the gentle queen of Louis XVI., he escaped the
misfortunes of almost every one of his contempora¬
ries, including Laplace, Lavoisier, and Delambre ; he
retained his scientific appointments throughout all
the frenzy of the French Revolution. His mildness
of disposition and disinterested devotion to science,
more than the European celebrity of his name, con¬
tributed to this result. He was equally fortunate
in his scientific relations. Euler, D’Alembert, and
Laplace, whilst they were emphatically his rivals,
were also his sincere friends. If he ever felt jealousy,
it was perhaps towards those who, he thought, at¬
tained too easily by circumstances to a high reputa¬
tion : Monge seems to have been of this number. It
is remarkable that for a series of years Lagrange di¬
verted his mind altogether from mathematics, and
studied chemistry, natural history, and even meta¬
physics. His reply is well known, when asked how
he liked the first of these sciences ; “ Oh,” said he,
“ I find it on trial as easy as algebra.” It may be
doubted whether in our own day he would have
given as favourable an opinion !
He was unassuming in conversation, and dis- (590
liked speaking of himself. His commonest answer
was “ I don’t know.” He was happy in his domestic
relations, and died universally honoured and regret¬
ted, 10th April 1813.
§ 2. Laplace.—Lunar Theory Improved.—Great Inequality of Jupiter and Saturn. Theory of
the Tides.—Young; Dr Whewell ; Mr Airy.— Theory of Probabilities.—Character of
Laplace as a Physicist and Author.
(60.) Pierre Simon Laplace has generally, and not
Laplace. without reason, been considered as a sort of exemplar
or type of the highest class of mathematical natural
philosophers of this, or rather the immediately preced¬
ing age. The causes of this, and the degree in which
it is warranted, we shall endeavour to state towards
the close of this section. In the meantime, finding it
quite impossible within our prescribed limits to notice,
ever so briefly, all his more material investigations,
we shall select three or four marked by their ori¬
ginality and general interest. Such are, 1. His im¬
provements of the lunar theory. 2. His discovery
of the cause of the great inequality of Jupiter and
Saturn’s motions. 3. His theory of the tides. 4.
His work on probabilities. 5. We shall consider
his character as a general physicist, and as a writer.
(61.) First, then, we are to speak of the improve-
mentsln" ments of the lunar theory effected by him. The ap-
the Lunar plication of Newton’s own principles to the perfecting
Theory. 0f the theory of the moon’s motion has been related
in Sir John Leslie’s Dissertation, and so far as the
labours of Clairaut, D’Alembert, Euler, and Mayer,
are concerned, belongs distinctly to the middle por¬
tion of the last century. The errors of Mayer’s
tables little exceeded one minute of space, which was
twice more accurate than in Halley’s time. With
one important exception, the main. outstanding dif¬
ferences between theory and observation had disap¬
peared. The eclipses recorded in the Arabic and
Chaldean annals could not '(as Halley first observed)
be correctly explained by the motion of the moon as
given by recent tables. At length it became admit¬
ted that the mean motion of the moon has been
accelerated from century to century by a minute
quantity, which, in the lapse of thousands of years,
has become recognisable. It amounts to this, that
the moon comes to the meridian two hours sooner
than she would have done had her present period
remained invariable from the earliest astronomical
records of eclipses. It is at once evident how delicate
a test this must be of changes otherwise imperceptible.
The effect on the dimension of the moon’s orbit maybe
thus expressed, that at each lunation she approaches
nearer to the earth than during the last by one-four¬
teenth of an inch! thus describing a spiral of almost
infinitely slow convergence. The minuteness of the
effect may be illustrated by the shortening of the
pendulum of a clock by an amount absolutely in¬
sensible, which yet, after days and weeks, will alter
by many seconds the time shown by the hands. Secular
After several unsuccessful speculations as to accelera-
the cause of this anomaly, Laplace, in 1787, thus sa- ^n°f lhe
tisfactorily accounts for it:—It is well known that the
sun’s attraction on the earth and moon lessens, on
the whole, the tendency of the latter to the former,
and lengthens permanently the lunar period. But,
so far as this effect is uniform, it does not directly
appear. The effect is greater, however, when the
earth is near the sun than when it is farther off.
The lunations are therefore longer in winter (when
the earth is in perihelion) than in summer. This
is called the annual equation, and the amount is
very sensible for this reason, that (as may be easily
seen) the perturbing force varies inversely as the
cube of the sun’s distance. * Now, though the earth’s
mean distance from the sun has not varied in the
lapse of ages, the excentricity of the earth’s orbit
has been diminishing from the earliest historic times,
and the average inverse cube of the distance has
Chap. II., § 2.]
PHYSICAL ASTRONOMY—LAPLACE.
815
(63.)
Earth’s
ellipticity
and solar
parallax
deduced
from the
moon’s
motion.
been also slowly increasing. The result is that the
moon’s motion has been continually accelerated.
Now, we have in the last section referred by anti¬
cipation to this acceleration as having led to the
belief that the moon must at last fall to the earth.
Laplace’s discovery, however, shows that the acce¬
leration has a limit, depending on that of the ex-
centricity of the earth’s orbit, which having reached
its minimum, the lunar mean motion will begin to
be retarded, and will continue so through a vast
cycle of ages, and so on alternately. Theory enables
us to assign, with considerable accuracy, the amount
of the acceleration, which is now about lO'' of lon¬
gitude in a century.1
Besides this very satisfactory discovery, Laplace
investigated three of the lunar inequalities in a man¬
ner leading to curious and unexpected results. Two
of these depend on the spheroidal figure of the earth.
The nutation of the earth’s axis, which is due to the
attraction of the moon on the protuberant equatoreal
parts of the earth, is exactly reproduced by the equi¬
valence of action and reaction in the movements of
the lunar orbit, only less perceptible in degree on
account of the length of the leverage at which they
are effected. The inequality of the moon’s motion
in latitude may be used to determine the degree of
compression of our globe at the poles. Laplace de¬
duced from the Greenwich observations of the moon
the fraction and, from a relative inequality in
longitude, ; a coincidence really astonishing, not
only as between themselves, but also when compared
with the mean result of laborious investigations by
actual measurement of the earth’s surface. The other
result we referred to was the determination from the
lunar theory of the solar parallax,—in other words,
the distance of the earth from the sun, which enters
into the expression of a certain inequality of the
moon’s motion in longitude. From the observed
amount of this inequality, Laplace obtained a value
of the solar parallax exactly coincident with that
obtained with so much labour on occasion of the
transit of Venus in 1769. Strange and admirable
result (as Laplace himself remarks), that the astro¬
nomer, immured in his observatory, and watching our
satellite through his telescopes, and reading the re¬
sult by the aid of mathematical analysis and the
theory of gravitation, should be able to determine the
figure of our earth, and its distance from the sun,
with perhaps quite as great accuracy as by any direct
measurements. Truly the wonders of fact exceed
those of fiction, and the divinations of true science
may match the pretensions of her counterfeit, astro-
logy-
In conclusion of this subject, I regret that space (64.)
does not allow me to advert particularly to Laplace’s The?ry ,of
remarkable success in accounting for some singular satellites,
peculiarities in the system of Jupiter’s satellites,
arising from, and partly occasioning, an exact com-
mensurability in the periods of some of them (which
Sir John Herschel has lately observed to hold also
in the Saturnian system in a somewhat different
manner), a case which we have seen to be especially
excluded in the instance of the planets, and which
has been pronounced by a very competent judge (Mr
Airy) to be “ the most curious and complicated sys¬
tem that has ever been reduced to calculation.” It
ought to be stated, however, that Laplace’s dis¬
coveries were based upon a previous and highly
original investigation of Lagrange.
II. In the second place, we shall briefly state the (65.)
nature of Laplace’s happy explanation of a great in-^011? i^1_
equality of the solar system, to which, like the fact^f j^p^.
of the lunar acceleration, especial attention had been and Sa-
called by the sagacity of Halley, and which, like it,turn-
resisting all the efforts of geometers to interpret,
threatened the credibility of the Newtonian theory of
gravity. We are therefore to look upon this step as
something more than a solution of a difficult problem;
it was a new, peculiar, and unsuspected combination
of circumstances on which it depended, and the solu¬
tion afforded a key in all time coming to difficulties
depending upon a like cause.
Halley had ascertained, that by comparing mo- (66.)
dern with the most ancient observations of Jupiter and^lsgtory of
Saturn, the mean motion of the former planet had been qualities *;
accelerated, and that of the latter retarded. Lambert
remarked subsequently that, if we confine ourselves
to modern observations alone, an opposite change
would appear to be in progress. The amount of the
error of the tables was so considerable (amounting to
20' or more in the middle of the eighteenth century,
and capable, in fact, of becoming much larger), as to
have been (along with the apsidal motion of the lunar
orbit) one of the first subjects of anxiety and specu¬
lation to geometers, when the Newtonian theory came
fairly into discussion. For nearly forty years this
stubborn inequality was vainly attempted to be ac¬
counted for by Euler, Clairaut, D’Alembert, Lagrange,
and by Laplace himself,, before the latter hit upon
the true cause of the anomaly. It was long, and
naturally, believed to be a properly secular inequa¬
lity, arising from the average mutual effects of the
planets Jupiter and Saturn, though Lambert’s re¬
mark rendered this less probable. - It was in the course
of the consequent research that Laplace proved that
the mutual action of the.two planets could produce
We here add that very recently Mr Adams has discovered that Laplace, and also his followers, in confining their at¬
tention to the radial effect of the sun’s interference with the lunar motions, as affected by the excentricity of the earth’s orbit,
have unwarrantably assumed that the area described by the moon a unit of time is invariable. He finds, on the contrary, tan¬
gential perturbations depending on the same cause, and sensibly modifying the amount of secular mean motion deduced from
theory.—(Philosophical Transactions, 1853.)
816
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
their
origin ;
their
amount.
(67.)
Their
periods.
no 'permanent alteration of tlie mean motion of
either; a conclusion which, as we have seen in the
last section, he afterwards generalized for the pla¬
netary system. Several other memoirs by Lagrange
and himself followed; and when the question be¬
came thus narrowed to periodic perturbations only,
Laplace, with characteristic ardour and resolution,
determined to search out every term which could affect
the result; an irksome task, less congenial to the gene¬
ralizing spirit of Lagrange. He had already noticed,
in his memoir of 1773, that Euler and Lagrange had,
in their researches on this very subject, omitted terms,
multiplied by sines and cosines of very small angles,
which yet might, in the process of integration, be¬
come considerable by the largeness of the coefficients.
Eleven years later he detected, in the expansion of
the mutual perturbation of Jupiter and Saturn, terms
of this kind. The coefficient (or maximum value of
the term) is in this case divided by the square1- of the
same quantity which renders the angle under the sine
or cosine small. These terms were indeed likewise
multiplied by the cubes of the excentricity, or like
small quantities ; but notwithstanding this, by reason
of the small divisor just mentioned, they were capable
of attaining a formidable magnitude ; in the case of
Jupiter, to 21', and of Saturn, to 48' or 49'. That
so small a force should produce so large an effect is
due to the very long period of the most considerable
portion of this inequality, which, in fact, led to its
being confounded with perturbations properly secu¬
lar. The period of complete recurrence of the effects
is about 920 years; and during half this time the
motion of one planet is being constantly accelerated,
and that of the other retarded; during the other half
the action is reversed. An effect continually in¬
creasing or diminishing for so long a time, and be¬
tween the two most massive of the planetary bodies,
is evidently liable to become considerable. The
maximum displacement of Jupiter and Saturn
Laplace found by calculation to have occurred in
1560, explaining the peculiarity above mentioned
in the comparison of ancient with modern observa¬
tions.
When we look to the physical cause of the large¬
ness of these particular perturbative terms, it is found
to be this ;—that the period of revolution of Jupiter
compared to that of Saturn, is almost as the num¬
bers 2 and 5 :—-in other words to the near commen-
surability of the mean motions. Were they exactly
in proportion to these numbers, formidable and per¬
manent changes would possibly result in the orbits.
As it is, the planets come into conjunction when Jupiter
has completed 5 revolutions, and about ^th more;
Saturn 2 revolutions, and 3\th more. Consequently
the point of conjunction travels round the circumfer¬
ence after about 44 conjunctions have occurred, which
requires nearly 2700 years. But a little considera¬
tion will show that conjunctions occur successively
at three nearly equidistant points of the circumference;
consequently the two planets will have been presented
to one another in every possible variety of configu¬
ration, when the point of conjunction has travelled
one-third round the circumference, that is in about
900 years.
The effect of this great improvement in the (68.)
Theory of Jupiter and Saturn was, that the most an¬
cient observations were completely reconciled with the
modern, and the modern with one another; the errors
of the tables were immediately reduced to one-tenth
of their former amount, and soon after to much less.
III. The third topic which I must shortly discuss in (69.)
connection with the career of Laplace, is the Theory Theory of
of the Tides. the Tides-
The Newtonian Theory of the Tides has been ex- (70.)
plained in Mr Playfair’s Dissertation, but its progress Newton’s,
during the 18 th century has not been adverted to in or
the continuation by Sir John Leslie. It will be suf-the Equ’ili.
ficient to state here, that it was pursued into its conse- brium
quences with ability and success by Daniel Bernouilli,Tlieory'
who in 1740 shared a prize of the French Academy
of Sciences on this subject, along with Euler, Mac-
laurin, and Cavalleri, a Jesuit, the last a supporter of
the Cartesian vortices. It was, perhaps, the conclud¬
ing honour paid to that once popular theory.
The Tidal Theory of Newton and Bernouilli (71.)
presumes the earth to be at rest; and also the watersIts results,
of the ocean to be at rest, and at every moment in a
state of equilibrium between the force of gravity,
tending to the earth’s centre, and the lesser forces
tending towards the sun and moon. That a theory,
founded on suppositions so far from the truth (not to
mention the irregular distribution of sea and land on
the earth’s surface), should in any manner or degree
represent correctly what happens, may be matter of
just surprise. The leading phenomena are however
tolerably consistent with it; the dependence of the
great tides on the moon’s position with respect to
the meridian of the port; the spring and neap tides
when the sun’s action and that of the moon conspire
with or oppose one another; the priming and lagging
of the tides depending on the displacement of the vertex
of the compound ellipsoid due to the combined effect
of the sun’s and moon’s attraction, depending therefore
on the moon’s elongation from the sun ; the effects of
the moon being in the nearer or remoter part of her
orbit; all these facts are indicated by the Equilibrium
Theory (as it has been termed), and are also results
of observation. The theory, however, does not give
the true depth of tide, nor (except in casual instances)
does the time of high and low water coincide with
theory ; besides many minor imperfections.
Laplace had the singular boldness to attempt
the solution of a problem, which is more one of hydro-
(72.)
1 In consequence of a double integration in respect of the time.
Chap. II., § 2.]
PHYSICAL ASTRONOMY—LAPLACE.
817
Laplace’s dynamics than of astronomy, and to estimate all the
Dynamical causes of movement of the particles of a heavy fluid,
Theory. surrounding a spheroidal rotating nucleus exposed to
the attractions of the sun and moon. This he did in
a series of memoirs, more systematically condensed in
the Traite de Mecanique Celeste, and it may safely
be affirmed that no other mathematician of his day
was equal to the labours and disappointments of an
investigation attended with every species of difficulty,
in which each result must be attained by a combina¬
tion of general sagacity with mathematical rigour, and
for the verification of which observations were yet in
a great measure wanting. The Theory of the Tides
was, upon the whole, the most arduous and compli¬
cated problem which could well be conceived, in a
branch of science (hydrodynamics) hitherto remark¬
ably little successful in predicting the results of the
most simple and arbitrarily selected experiments.
(73.) That Laplace has been in a measure successful
cultysuc^ an undertaking must be considered the highest
test of his genius, especially in reducing his mathe¬
matics to practical application; but the result has
been a treatise so profound and obscure (I mean as
regards the tide theory), that very few persons have
attempted to master its difficulties. Mr Airy, the
present astronomer royal, has done a great service
to men of science, and to that far wider community
whom the laws of the tides nearly interest, by giving
a connected and tolerably elementary view of La¬
place’s investigation, which he states confidently to
be “ the most obscure of the Mecanique Celeste."
(74.) In this theory the figure of the ocean at any
pie ten ess.* moment is considered as a dynamical problem ; and
that figure as a momentary state arising from the in¬
ternal movements of the fluid itself, as well as from
the variation of the external forces. The resulting
differential equations, expressing the attractions of
the sun, moon, and earth, the rotatory movement of
the earth,‘and the pressure of the water itself in mo¬
tion, are abundantly complex, and the solutions only
partial and imperfect. The inferences from these
solutions, too, partake not only of their imperfection,
but, since they take no cognisance of the irregular
distribution of land and water, present cases almost
impossible to verify by observation. Some of the
results are indeed so paradoxical, that without bet¬
ter evidence of their truth we do not further allude
to them.
Three^he tidal effects are divided by Laplace into three
classes of c^asses > the distinction of which, however, cannot be
Tides. called a discovery of his. The first class are inde¬
pendent of the earth’s rotation, and are practically
insignificant. The second class includes the diurnal
tide occurring once in about 24 hours. Concerning
it, Laplace draws this conclusion, that its rise and fall
(not, however, its horizontal motion) are insensible if
the depth of the ocean is uniform ;a and being practi¬
cally insensible in most latitudes, we have thence an
argument of more or less weight for a general
tendency to uniformity in the depth of the sea. The
third class of tides are the ordinary semi-diurnal
tides. They afford, as Newton acutely perceived, the
most direct and attainable measure of the relative at¬
tractions of the sun and moon. We have the sum of
these attractions at the conjunctions and oppositions
of the luminaries, and the difference when they are
90° apart; and a higher maximum when both bodies
are without latitude. From the observation of the
tides on the Severn near Bristol, Newton computed
the relative action of the moon and sun to be as
4"48 to 1 ; but this value is much too great, and
gave far too large a relative mass to the moon. The
result in the harbour of Brest, from observations made
under Laplace’s direction, is about 2-90 to 1; and the
moon’s mass y^th that of the earth, agreeing almost
identically with that deduced from the nutation of
the earth’s axis caused by her attraction. Observa¬
tions at London and Liverpool reduced by Sir John
Lubbock and Dr Whewell give about 2-66 to l.2
From the general theory of Laplace, the follow- (76.)
ing results have been deduced with confidence :—(1.) Laplace’s
That the stability of the ocean is secure, whilst the resuits>
density of the ocean is inferior to that of the earth
generally ; which it is about five or six times. (2.)
That the phenomenon of precession is not modified
by the fluid covering of the globe.
In the application of his theory to special cases, (77.)
Laplace is compelled to have recourse to an assump¬
tion entirely arbitrary—namely, that the periodic
fluctuations, however otherwise modified by circum¬
stances, recur in the same periods as the causes to
which they are due. In this manner he conciliates the
results of observation with his theory, which the latter
would have been altogether incompetent to predict.
The general merits of Laplace’s theory we will sum (78.)
up in the words of Mr Airy, who, of all his succes- Character
sors, has probably most attentively studied it:—“ If, °f L^' .
putting from our thoughts the details of the invest!- vestigation.
gation, we consider its general plan and objects, we
must allow it to be one of the most splendid works
of the greatest mathematician of the past age. To
appreciate this, the reader must consider—first, the
boldness of the writer who, having a clear under¬
standing of the gross imperfection of the methods of
his predecessors, had also the courage deliberately
to take up the problem on grounds fundamentally
correct (however it might be limited by suppositions
afterwards introduced); secondly, the general diffi-
•d 1 Dr \oung ^sserts that the conclusion will not hold unless the depth be also evanescent. Laplace has shown in his Fifth
Hook that the disappearance of diurnal tides will take place only when the nucleus is completely covered.
These ratios, however, being found to depend upon the configuration of the coast or estuary, cannot he used directlu to de¬
termine the relative action of the sun and moon. See Phil. Trans., 1845, p. 42
vol. r. 5 L
818
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
culty of treating the motions of fluids; thirdly, the
peculiar difficulty of treating the motions when the
fluids cover an area which is not plane hut convex ;
and, fourthly, the sagacity of perceiving that it was
necessary to consider the earth as a revolving body,
and the skill of correctly introducing this considera¬
tion. The last point alone, in our opinion, gives a
greater claim for reputation than the boasted explana¬
tion of the long inequality of Jupiter and Saturn.” 1
We must, however, qualify this eulogy by adding, in
the words of the same writer, that Laplace’s theory,
though based on sounder principles than the equili¬
brium theory, “ has far too little regard to the actual
state of the earth to serve for the explanation of even
the principal phenomena of the tides.” It is, in fact,
like many other productions of the same age and
school, a great display of ingenuity and mathemati¬
cal skill, which hardly yields a single result worthy
of confidence, or agreeing with nature, except by the
abandonment of its deductive rigour, or a concealed
induction backwards from the phenomena to be ac¬
counted for. The same amount of skill and resource
which Mr Airy has shown in adapting it to his own
views, and to recent observations, would probably
have sufficed to construct a theory from the founda¬
tion. By others the attempt seems to have been
abandoned as hopeless.
C79-) Since our limits will not permit us to return to
TLdls —Dr ^ie su^jec^ tides, we shall here briefly state the
Whewell progress of the subject since the time of Laplace.
Sir J. Lub-The chief steps have consisted in co-ordinating the
bode. results of observation and analyzing them into their
partial phenomena, by the help of Newton’s and
Bernouilli’s theory. This labour has been greatly
advanced by Dr Whewell, and also by Sir John Lub-
Cotidal bock. The former has constructed maps of “ cotidal
lines. lines,” which, indicating the relative time of high
water in different parts of the globe, give us a gra¬
phic conception of the course and propagation of the
tidal wave. The tides of the Eastern Pacific are but
little known ; but a vast wave advances northwards
between Australia and Africa, diverted or retarded
by the obstacles it meets with in the Indian Archi¬
pelago. Another (and to us the most important)
branch sets from south to north up the vast canal of
the Atlantic, where it is gradually complicated by
local tides, having their origin in the wide expanse
between Africa and the Gulf of Mexico. The two
sets of waves sometimes reinforce, sometimes oppose,
one another; they are prolonged to the western
shores of England and Norway, where the tidal im¬
pulse arrives 24 hours after it passed the Cape of
Good Hope. It is propagated most rapidly at a dis¬
tance from coasts, and is retarded in narrows and
shallows. It sends offshoots into every bay and
strait, always greatly retarded in point of time (ap¬
parently by friction), but often increased in elevation
by concentration of the effect in a gradually narrow¬
ing channel, as we see in the exaggerated tides of the
river Amazon, the Severn, and the Bay of Fundy.
The same place may be the seat of several tides at
once, which may increase or destroy one another;
thus, a small tide is propagated through the Straits
of Dover as far as the Dutch coast, where it only
arrives simultaneously with the principal wave,
which has made the entire tour of Great Britain.
As regards the progress of theory, Dr Thomas Th^^of
Young, whose character as one of the greatest Dr Young,
philosophers of the past age we shall have to con¬
sider in another chapter, next after Laplace grappled
with the difficulties of this arduous subject. Em¬
ploying mathematical methods of inferior power but
greater directness, and taking into account causes of
local action which Laplace had not ventured to in¬
clude in his analysis, he gradually matured a theory
adequate to represent many of the results of ex¬
perience, of which Laplace gives no account.
He distinguishes the results of t\vQ forced and/ree
oscillations of the sea ; the former resulting from the force(i
direct action of the sun and moon combined with the waves,
rotation of the earth, and whose periods of rise and
fall are determined solely by those external causes
(external, I mean, to the mass of the ocean) ; the
free waves, on the contrary, derived from the former,
are transmitted with velocities depending on the me¬
chanism of the fluid itself, on its depth, and on the
resistances arising from friction to which those mo¬
tions are exposed. These all-important modifications
of the dynamical Theoiy of the Tides were deduced
by Dr Young from the general theory of oscillations
and resistances, and from the laws of fluids detected
by Dubuat,2 and he applied them with no ordinary
skill to the solution of the problems of tides in
oceans, estuaries, and rivers. It is an extraordinary
fact, and not without significance, in the history of
science, that these researches of Young, published
anonymously in the Supplement to the Sixth Edition
of the Encyclopaedia Britannica, and in the Seventh
Edition of this work, and likewise in several jour¬
nals and reviews, so generally escaped notice as to
have been almost unknown till Dr Peacock, in his
recently published “ Life and Miscellaneous Works
of Dr Thomas Young” has fortunately recalled
attention to their existence and their important
results.
In doing so, Dr Peacock has communicated with on
Mr Airy, whose very valuable article on Tides and Ti(jeg
Waves has been above referred to (78), and has Waves,
ascertained from him that Dr Young’s researches
had escaped his notice when he undertook that
elaborate recension of Laplace’s theory, and made
those important additions to it to which I have
Encyclopaedia Metropolitana, “ Tides and Waves,” art. 117.
See Chapter IV., Section 6, where we shall return to some portion of this subject.
Chap. II., § 2.]
PHYSICAL ASTRONOMY—LAPLACE.
819
called attention.1 It is very satisfactory to find that, applied it to classes of problems altogether new.
by their independent and very different modes of We find that most of the principles of the Calculus
analysis, Mr Airy and Dr \oung have arrived at were established by James Bernouilli, in the earliest
Jesuits generally coincident. It is in the essay part of the eighteenth century, who gave the first History of
of the former that most readers will now seek for an application of the Binomial Theorem to determinetlleIloctrine
acquaintance with Laplace’s abstruse investigations, the probability of a particular combination of a given Cllances'
whilst they will find in it the bearing of experiments number of things occurring, in preference to all the
moie recent than the time of Young on the propa- other equally possible combinations. Stirling dis-
gation of waves in canals, the theory of Mr Airy, covered a curious theorem for approximating to the
beginning as it were at the opposite end from that of continued product of the arithmetical sei-ies of num-
Laplace, and offering far more points of contact with bers carried to any extent, which perpetually occurs
actual observation, particulaidy in the Tides of in such calculations. Demoivre carried out Halley’s
Rivers and Estuaries. The theory of \oungwill application of it to the laws of mortality. Condorcet
naturally be best studied in his own article Tides, applied it to moral questions; Mitchell to natural
in this Encyclopedia. phenomena, considered as the results of accident or
..... design; Lagrange to errors of observation. The
Doctrine of T , In Place’ we connect name of chief applications of the Theory of Probabilitv are Itsehiefap-
ProbabUi- Laplace with the progress, during the period we are the following 1. To chances known d. 'priori, as plications,
ties. considering, of the curious doctrine of probability, that of throwing two given numbers with dice, the
or the laws of chance and expectation. These he whole range of possibilities being known with preci-
discussed in two works, the Theorie Analytique and sion. 2. The calculation of the expectation of future
the Essai Philosophique sur les Probabilit4s—the first events on a great or average scale, deduced from the
the most mathematically profound, the last the most past course of events observed also on a great or
popular and elegant, account of the subject which average scale. Of this description are the calcula-
has yet been given. Nearly all mathematicians are tions of life assurance, first tabulated by Halley. 3.
agreed on two points—/m, in considering this the To find the most probable result of a number of in¬
most subtle ’ and “ difficult to handle” of all the dependent observations and problems of a like kind,
applications of their science, involving a perpetual 4. To the proof of causation as opposed to accident
lecunence to contingencies, and to elements of the or “random,” derived from existing combinations of
argument easily left out of account, and in which, facts. 5. To the probability of testimony, and the
more than in any other, it is dangerous to let sleep confidence due to legal decisions. None of these
foi a moment the severely reasoning faculty, or per- inquiries are peculiar to Laplace, or originated with
mit it to be lulled to security amidst the maze of him. We select, however, for a brief notice (which
symbolic tiansformation. In truth, from experience, must be confined to a few sentences) the third and
I am disposed to receive with doubt the solution of fourth of these applications.
even a tolerably simple problem of chances, unless The chances are enormous against the most expe- (85.)
two competent persons at least have concurred in rienced marksman’s hitting the bull’s eye of a target. To find the
verifying it. Secondly, Mathematicians are agreed But if he make many shots in succession, the balls *)ro*
in consideimg Laplace’s TAeoWe nearly, if not quite, will be lodged round about the spot at which he suit of a
the ablest specimen of mathematical writing of his aimed, and they will be fewer in each successive ringnumt)er of
age, notwithstanding a degree of obscurity and repe- of equal area drawn round the mark. The degree ^ndePen‘
tition in addition to the inherent abstruseness of the of their scattering will depend upon the skill of the vations8^"
subject, which render it, in the opinion of one of the marksman; but in all cases the most probable result
most learned and extensively read of our pure ma- will be, that the point aimed at is the centre of gravity
thematicians,2 “ by very much the most difficult ma- of the shots. This may be shown to be equivalent to
thematical work he ever met with.” saying that the most probable result of any number of
|m^4') A single paragraph has been devoted to the subject equally reliable observations is that which will make
ments in its °f Probabilities in Sir John Leslie’s Dissertation, the sum of the squares of the outstanding errors a
investiga- elating to its earlier history; and the subject was so minimum. This rule was conjecturally proposed by Legendre’s
tion by popular during the last century, that there was Legendre in 1806. A demonstration of its truth was method of
aP ace- scarcely an eminent mathematician who did not add first published by Laplace. It is of great practicalleast
something to its practical development; so that La- use in deducing the results of complex observations, SCLuares‘
place may be considered rather to have enlarged such as those of Astronomy, and generally in com-
widely its applications by means of his almost unex- bining “ equations of condition” more numerous than
ampled power in handling the calculus, than to have the quantities whose value is sought to be extracted
improved or established its first principles, or even from them. In very many cases, however, a graphical
1 See note to p. 262 of the Second Volume of “ Young’s Miscellaneous Works,” by Peacock.
2 Professor He Morgan in Encyclopaedia Metropolitana.
820
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
Probable
error.
(86.)
method of interpolation will serve the same purpose,
as well as save a very tedious calculation. Perhaps too
much, importance has been assigned to the “ probable
mean error” of a single observation deduced fiom
manv individual errors by the same theory. If a
man has but one shot at a target, it is perfectly un¬
certain (by hypothesis) whether that shot be one of
his best, or one of his worst, or one of his middling
ones. But as there are more middling hits than
verv bad or very good ones, there is a certain dis¬
tance which it will be safe to bet (*. e. for which the
probability is £), that he will not exceed ; though it
would be a strange occurrence indeed, if he exactly
struck the ring in question. This is all that is meant
by the phrase “ probable errorit is an entirely
artificial number, which serves to give a sort of nume¬
rical value of the skill of the performer, but is other¬
wise of no importance. Its application has sometimes
been strangely mistaken. Even the “ rule of least
squares” is often misapplied, and empirical laws al¬
together false have been deduced from it; for it is
rare in practice that the chances of error of observa¬
tion of a varying quantity are the same throughout
the limits of observation.
But those applications of the doctrine of proba-
bility which pretend to give us a measure of our belief
mony and in the constancy of natural laws, in the confidence due
of Design, to testimony and to the teachings of history, in the
proofs of design in cosmical arrangements,—are
inquiries which, from their connection wdth meta¬
physics, religion, andmorals,havehad a higher interest
for mankind at large than ordinary problems about
cai’ds and dice. To these Laplace paid peculiar
attention ; and the reputation of his name tended to
create in others a belief that the analysis he so power¬
fully wielded could communicate a portion of its
certainty to the data subjected to it, and gave a
currency to many of his conclusions to which we
believe them by no means entitled. Professor Play¬
fair, one of the most ardent of Laplace’s admirers, has
recorded (in a criticism in the Edinburgh Review, of
the works we are considering) his total dissent from
Laplace’s doctrine that the transmission from age to
age of the historic record of a fact diminishes its credi-
Laplace’s bility in a geometrical ratio. But a Cambridge
doctrines mathematician and speculative philosopher of singu-
H ’ lar penetration, Mr Leslie Ellis, has most formally
assailed1 the principle of nearly all Laplace’s esti¬
mates of our expectation of events arising from causes
unknown or assumed to be so, such, for instance, as that
a common cause determined the revolution of all the
planets in one direction. The subject of the meta¬
physics of probability evidently requires a complete
reconsideration ; and, owing to the singular subtlety of
the matter, it is one which few persons are competent
to handle. The state of health of Mr Ellis leaves us
little hope of his resuming the inquiry ; but two
eminent mathematicians, Mr De Morgan and Mr
Boole, have published considerable works chiefly
bearing upon it.
As an implement bearing upon discovery in (87.)
science, the Calculus of Probabilities has as yet been Probability
of little service. Whilst Laplace tries to indicate how ^
it guided his researches connected wnth planetary irre- covery.
gularities, every one sees at a glance that, with the
data before him, common sense must have outstripped
analysis. Laplace has called the doctrines of pro¬
bability “ good sense reduced to calculation.” What
is to be feared is, that the calculation should outstrip
the good sense.
Y. Fifthly, We are to consider Laplace’s charac- (88-)
ter as a general physicist and as a writer. character
In the former respect he stands in a higher posi- as a phy-
tion than that usually attained by eminent analysts, sicist, and
In
of his own a,8 an au'
fact, if xve compare him with any  thoi-
generation, we find him not only better acquainted
with physical principles, and more scrupulous in
taking account of them in his mathematical discus¬
sions, but even possessing skill and interest in ex¬
periments. The Calorimeter for measuring the capa¬
cities of bodies for heat wras the joint invention of
Lavoisier and himself; at least their memoir does
not assign to either a predominant share in it,2 3 * and
their determinations of the expansions of the metals
by heat seem also to have been made in common.
His happy discovery of the chief or sole cause of the Memoirs on
discrepancy between the theoretical and observed Heat>in
velocity of sound (due to the heat developed by com- ™™hmon
pression) would alone have given him a just reputa- Lavoisier,
tion, so anxiously had the matter been debated, and
so much was it involved in a purely mathematical
intricacy. Even in his great work on physical as¬
tronomy he takes a peculiar pleasure in embracing
topics of terrestrial physics. We there find discussed
the theory of barometrical measurements, the ques- On Baro-
tion of atmospheric tides, the laws of capillary attrac- metrical
tion, and the constitution of the gases. As to the first ^ast^re
of these topics he made a practical improvement on capillary
the formulse of his predecessors, so that his rules are Attraction,
in fact still in use. As regards capillary attraction,&
he wa’k materially anticipated by Young, who evi-fractionSi
dently considered his principles to have been pirated;
yet his theory, though obscured by a display of re¬
dundant mathematics, was a real improvement. His
theory of tides, and that of atmospheric refractions,
though closely connected with physical astronomy,
were in fact not less so with the doctrines of hydro-
1 Cambridge Transactions, Yol. VIII. The writer of these pages has also given his reasons for dissenting from the argu¬
ments of Michell (which have been sanctioned by the authority of Laplace) on an astronomical question as discussed by the
Theory of Probabilities. See Philosophical Magazine for December 1850.
3 Dr Black, the discoverer of latent heat (who was probably well-informed), states in a letter to Watt that he believes
Laplace to have been the inventor. See Correspondence of Watt on the Decomposition of Water, p. 66.
Chap. II., § 2.]
PHYSICAL ASTRONOMY—LAPLACE.
821
dynamics and optics; and we shall find very few
important branches of general physics in which he
has not left some permanent record of his interest,
in the course of his career of fifty-Jive years of
anxious devotion to science.
(89.) His largest and most systematic wmrk, the Traite
Meccinique Celeste, in five quarto volumes, was
canique n0^ onty most ably executed, hut exceedingly well
Cilate. timed. The applications of analysis to physical astro¬
nomy had been accumulating for nearly a century.
Hundreds of memoirs relating to them, dispersed
through many volumes in different languages, written
with varying ability, in various stages of scientific pro¬
gress, and with differing notations, presented a mass
of reading almost beyond the reach of the most reso¬
lute student. Laplace undertook to digest the whole
into one body of doctrine, composed throughout on
a uniform plan, with the best mathematical aids which
were known at the commencement of this century.
And though improvements and discoveries have been
since made, the methods and most of the results of
the Meeanique Celeste remain, with little variation,
the preferable ones of our own time. As a work of
labour, it may compete with the Principia of New-
Far less ton ; as an original work, it is of course immeasur-
tW the ’n^er^or- Its principles are, in fact, the same
frincipia; ^ose laid down in that immortal code, and its
deductions are collected (as we have said) from the
writings of Clairaut, D’Alembert, Euler, and Lagrange,
as well as from the previous memoirs of the author
himself. Laplace has been too sparing of his cita¬
tions and acknowledgments, and a consequence of
this literary avarice has been that he is sometimes
considered as more of a compiler and less of a dis¬
coverer than is justly his due. For however ill he
could have dispensed with the skilful preparations
of his illustrious rivals and contemporaries, his pre¬
eminent sagacity furnished on several occasions the
key-stone of the arch which imparted at once strength
and completeness to the fabric. We have seen in
the last section that though the credit of the theo¬
rems respecting the stability of the solar system is very
generally attributed to Lagrange, who, indeed, prin¬
cipally furnished the methods, and gave great gene-
yet gives rality to the results, yet the capital discovery of the
him justly invariability of the major axes of the planetary orbits
putatioiT" ^ue Eaplace. It was he, again, who removed
from the theory of gravity the two greatest and
most impracticable difficulties with which it had
ever been assailed—the anomaly of the lunar ac¬
celerations, and the great inequalities of Jupiter and
Saturn, and by so doing rendered it almost infinitely
improbable that any future discrepancy should more
than temporarily embarrass a theory which had tri¬
umphed in succession over such formidable causes of
doubt. True that Lagrange, in his memoir of 1783,
had come within a single step of the first of these
discoveries, and, by a process of exclusion, had almost
forced attention in the right direction respecting the
latter ; still Laplace seized the prize in both cases,
after a fair, prolonged, and arduous struggle. Now
these three discovei'ies wrere the greatest in physical
astronomy between those of D’Alembert and Clairaut
on the precession of the equinoxes, the motion of the
lunar apse, and the periodicity of comets,—and that
of Leverrier and Adams on the perturbations of
Uranus about a century later.
The universal testimony of mathematicians is to _
the effect that Lagrange was unrivalled as a pure compared
analyst, in his power of generalization, and in the with La-
inherent elegance of his methods ; that Laplace, £range-
with nearly equal power in using the calculus, had
more sagacity in its mechanical and astronomical
applications, or rather, perhaps, we should say, in
directing it to the discrimination of causes, and the
revelation of consequences.
In other respects he differed far more widely from (91.)
his illustrious compeer. He rather courted popu-His puMic
larity, and was pleased at being considered worthycharacter'
of political distinction. For a short time he was one
of Napoleon’s ministers; but the Emperor, it is said,
was more satisfied with his mathematical than with
his diplomatic talents. He had none of the shyness of
Lagrange, nor his repugnance to general society. He
received with affability and kindness those who were
introduced to him, and his attentions were after¬
wards recollected with gratitude by rising men of
science abroad. He had a villa at Arceuil, adjoining
that of Berthollet, and was one of the original mem¬
bers of the “ Societe d’Arceuil,” to whose memoirs
he contributed. He exercised a powerful influence and as a
in the Academy of Sciences, of which for a time he Member of
acted as dictator, and he was not very tolerant of demy of
views in science opposed to his own. The undula- Sciences,
tory theory of light he always opposed, and wTas
mainly determined in doing so by the facility with
which the attraction of luminous corpuscles could be
subjected to calculation.
The weak point of his scientific character was one so (92.)
natural, and perhaps so inseparable from his prevail Jj0ve
ing studies, that it is not fair to criticise it too severely, dispfay!
This was a love of analytical display in treating ques¬
tions which it rather embarrassed than illustrated;
and generally, a disposition to overrate the sphere of
mathematical discovery. This he had in common
with Euler, to whom he was very superior in physical
attainments and sagacity. His language, and that of
his eulogists,1 often amounts to the assumption that
1 For instance Arago says (speaking of the invariability of the major axes): “ Enfin par la toute-puissance d’une formula
mathematique, le monde materiel se trouva raffermi sur ses fondements” (Annuaire, 1844, p. 304). This is indeed the idolatry
of mathematics. Many examples may he found in Laplace’s writings on Probability ; which occasioned Mr Ellis to say of him, that
“ to Laplace all the lessons of History were merely confirmations of the ‘ resultats de calcul.’ ” To the same effect was the mot
of Napoleon, “ that Laplace carried into the art of government the principles of the infinitesimal calculus.”
822
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
the marvellous power of analysis, in unravelling intri¬
cate consequences of admitted or assumed laws, could
supply deficiencies of primary conceptions of the laws
of nature, or could teach men fundamental truths in
scicncG.
(93.) To add to the remarkable list of Laplace s endow-
His Systeme jnents one more ; he was a perspicuous and elegant
du Monde. wrjter> jjjg Systeme du Monde contains a popular
exposition of astronomy in theory and practice en¬
tirely original in its plan and execution, and though
frequently imitated, it is still perhaps the first of its
clciss.
Laplace was born in Normandy 23d March 1749, (94.)
and died the 5th May 1827, leaving in the Academy Date of ^
he bad so long honoured no one within many degrees death
of his ability in the same peculiar walk of science.
s 3 Legendre.—Ivory.—JVieori/ of Integration; Elliptic Transcendants (Abel, Jacobi).
§ The Attraction of Spheroids, and Theory of the Earth’s Figure. Atmospherical Refractions.
(95.)
Legendre.
(96.)
Distin¬
guished as
an able
mathe¬
matician.
(97.)
His re¬
searches on
Elliptic
Functions.
Adeien Makie Legendee was born in France in
1752, and died in 1833 (10th January); he was
consequently three years younger than Laplace, and
survived him by nearly six years. He formed, there¬
fore, an integral part of that constellation of mathe¬
matical talent of which Paris wns for more than
two generations the main centre. Like his illustrious
compeers Lagrange and Laplace, he laboured with
enthusiasm all the days ol his life, and like them was
engaged in editing and improving bis works down
almost to the day of his death, at the ripe age of four¬
score.
The mathematical career of Legendre was less
splendid than that of the other two whom we have
just mentioned. He did not possess the wonderful
powers of generalization of Lagrange, and he wanted
the flexibility of mind, and the general physical
knowledge, of Laplace. Legendre was very strictly a
mathematician ; and he has been exceeded by none
in the unquenchable zeal with which he pursued sub¬
jects of a dry and even repulsive character, often
till he had hunted them down by sheer force of ap¬
plication, or, to adopt the metaphor applied to him by
Lagrange, until he carried, sword in hand, the strong¬
hold which he besieged.
No more striking proof can be given of these state¬
ments than the unflinching pertinacity with which,
during nearly fifty years (1786-1833), he studied and
improved the theory of Integration, applicable to those
cases frequently occurring, which involve the higher
powers of the independent variable, and which do not
usually admit of finite expression. Two large works,
the Exercises du Calcul Integral (1811), and the
Traite des Fonctions Elliptiques (1827—32),—the lat¬
ter in good measure a republication of the materials of
the former,—bear testimony to his diligence; and these
works were almost entirely original, and contained
tables of most laboured construction, calculated by
himself. Hardly any mathematician entered into
competition or co-operation with him until his
labours were drawing to a close, when, with a libe¬
rality worthy of all commendation, he welcomed the
analytical discoveries of Abel and Jacobi,, which
were to give an unlooked-for extension to his own.
These methods of integration, and their reference to
certain properties of the Lemmscate and the Ellipse,
originated in the early part of the last century
with Fagnano and Euler. Legendre took up the
subject exactly where Euler left it, and finally re¬
duced the large class of expressions to which his
methods are applicable to three standard forms or in¬
tegrals in which the independent variable is always
expressed by a circular function, and to which a
numerical approximation may always be made by
means of the tables calculated by himself.
Abel, who succeeded in generalizing Legendre s (98.)
methods to a far greater extent, was a native of
Norway, born in 1802 (25th August), and the same
at the premature age of twenty-six (1829, 26thsubject;his
April). His principal memoir was presented to the
Institute when he was only twenty-four years old,
and, to use the language of Mr Leslie Ellis, u when
the resources of the integral calculus were appar¬
ently exhausted, Abel was enabled to pass, into
new fields of research by bringing it into intimate
connection with a new branch ol analysis, namely
the Theory of Equations. The manner in which
this was done shows that he was not unworthy to
follow in the path of Euler and of Lagrange.
Legendre’s eulogy of Abel was concise : • ‘ Quelle
tete celle du jeune Norvegien!” It is less agreeable
to add that the life of Abel was perhaps shortened by
poverty and care. Though ultimately befriended by
Legendre, Poisson, and others,his firstvisit to Paris (in
1826) occasioned nothing but disappointment, and his
great memoir (no unusual lot, for the same happened
to Fresnel) lay hopelessly lost amidst the papers of the
Institute for fifteen years. Much, however, to their
credit, the geometers above mentioned at length ad¬
dressed the King of Sweden on behalf of the rare genius
his dominions contained ; but in vain. Abel died ne¬
glected, unable even to print his researches, which were
tardily given to the world in a collected form, at the
expense of the government which refused to support
1 There is some discrepancy, as to the year of his birth, but I believe this to be correct.
2 Report on the recent progress of Analysis. British Association Report for 1846.
Chap. IT., § 3.]
PHYSICAL ASTRONOMY—LEGENDRE—IVORY.
823
(99.)
Legendre’s
researches
on the at¬
traction of
Ellipsoids,
(100.)
sometimes
in part at¬
tributed to
Laplace.
(101.)
History of
the subject,
(102.)
Other
works.
(103.)
Ivory.
him when alive. The French Academy, which had
buried his memoir in their most inaccessible “archives,”
decreed too late the unprecedented honour of a post¬
humous medal to his mother. Jacobi, the friendly
rival of Abel in his discoveries, died recently, at a
mature though not advanced age, at Kbnigsberg,
where he was professor.
Rut to return to the labours of Legendre. The
theory of the figure and attraction of the earth
and of other planets naturally divides itself into two
parts—(1.) the law of attraction of an ellipsoid on
a material point without or within it; (2.) the figure
of equilibrium of a fluid subjected to no forces but
the mutual attractions of its particles, and the cen¬
trifugal force due to its rotation. The latter of
these problems is still imperfectly solved, the former
completely so, and that mainly in consequence of the
labours of Legendre and Ivory.1
Though the services of Legendre are well known
and admitted, the superior address of Laplace in the
applications of mathematics has occasioned his re¬
ceiving the credit of what in some instances belonged
to the former.
Maclaurin, by an exercise of synthetic skill not
exceeded since the death of Newton, had demon¬
strated the attraction of an ellipsoid of revolution
upon a material point anywhere within it or on its
surface, as well as for an exterior point in the
prolongation of its axis or in the plane of its
equator. The same problem was afterwards ana¬
lytically solved by D’Alembert and Lagrange. In
1782, Legendre, by a profound and complicated
analysis, obtained an expression, by means of series,
for the attraction of an exterior particle generally,
and he was the first to imagine and employ those
artifices of calculation known usually by the name
of “ Laplace’s functions.” Laplace .made a step
towards the simplification of the expression of ex¬
terior attractions, but the complete solution was
reserved for Mr Ivory, as I shall mention below.
The other labours of Legendre need not be spe¬
cified here. He co-operated in the trigonometrical
survey of France, and gave the formula, known by
his name, for approximately reducing a spherical to
a plane triangle. He also wrote on the orbits of
comets, and on the method of least squares.
James Ivory, the most considerable British mathe¬
matician of his time, or that had appeared since Mac¬
laurin, was born at Dundee in 1765, and studied at St
Andrews along with Sir John Leslie. The most ac¬
tive period of his life was passed as mathematical pro¬
fessor at the Military College of Marlow (afterwards
removed to Sandhurst). He was essentially a self-
taught mathematician, and spent much of his time in
retirement. He fathomed in private the profoundest
writings of the most learned continental mathemati¬
cians, and, at a period when but few Englishmen
were able to understand those difficult works, he
showed his capacity of adding to their value by ori¬
ginal contributions, not unworthy of the first ana¬
lysts. We pass over his earlier contributions con¬
nected with mathematics and astronomy, several of
which are contained in the Transactions of the
Royal Society of Edinburgh, and proceed to his
most celebrated paper, published in the Philoso¬
phical Transactions for 1809, in which he com¬
pletely and definitely resolves the problem of attrac¬
tions for every class of ellipsoidal bodies. After
what has been stated above as to the position of the
problem as treated by Legendre, a few words will
explain the precise import of Ivory's Theorem, one of
the most celebrated mathematical results of that time.
We have seen that the attraction of an ellipsoid (104.)
on a point within or at its surface had been assigned H!s
by Maclaurin. The theorem in question enablesant The?r
us at once to reduce the case ot an exterior attracted attraction
point to that of a point on the surface of the ellipsoid.of Ellip-
Suppose an ellipsoid having the same excentricity,80lds'
and with the principal sections parallel to the first,
but whose surface passes through the given exterior
point. Let points on the surface whose co-ordinates
parallel to the three axes of the respective solids are
proportional to those axes be called corresponding
points; then the attraction parallel to each axis
which one of these bodies exerts on a point situated
on the surface of the other is to the attraction of the
latter on the “ corresponding point” of the sur¬
face of the former, as the product of the two other
axes of the first ellipsoid is to the product of the two
other axes of the second. By this means the attrac¬
tion on an exterior point is accurately expressed in
terms of the attraction on an interior point, which
is known. It is fair to add that both Legendre and
Laplace had some glimpses of the principle, though
they failed to apply it to the direct solution of the
problem, and between the publication of their Me¬
moirs and that of Mr Ivory there elapsed nearly a
quarter of a century.
Besides this paper, Ivory contributed many others (105.)
on the subject of the attraction of spheroids and theIIis othe"
theory of the figure of the earth, during a period ofpai)ers-
nearly thirty years; several of these were controversial,
and did not add materially to the progress of the sub¬
ject; others are considered as masterpieces of analyti¬
cal skill. One of the last subjects which occupied his
attention was the possible equilibrium of a spheroid
with three unequal axes, which Jacobi had discovered.
Between the labours of Ivory and those of Legen¬
dre a great analogy subsists; for the doctrine of ellip¬
tic integrals also occupied the attention of the former.
But next to the theory of attractions, that o£ At¬
mospheric Refraction most seriously engaged Ivory’s^m°r
attention. Its great importance in astronomy, andfract;^, 1
(106.)
(107.)
A tnio-
1 See the articles Attraction and Figure of the Earth (the former by Ivory) in this Encyclopaedia.
824
MATHEMATICAL
AND PHYSICAL SCIENCE.
[Diss. YI.
the curious mathematical difficulties which it pre¬
sents, renders it very interesting to analysts. La¬
place had applied to it his method of Generating
Functions; Kramp had introduced into his (now
scarce) treatise the almost new Calculus of Factorials ;
and others, like Bessel and Atkinson, had skilfully
combined theory and observation for the construc¬
tion of useful tables. One of the most curious re¬
sults of recent enquiries into this subject is, that Sir
Isaac Newton’s table of refractions (Phil. Trans.,
1721) must have been founded on a profound con¬
sideration of the problem, such as no one else thought
of till a much later period, and is so numerically ex¬
act as to agree closely with the later tables, Kramp’s
for example.1
(108.) Mr Ivory attained the age of seventy-seven, dying
His death.
on the 21st September 1842. Probably his unceasing
devotion to a confined and abstruse topic of enquiry,
reacting on a sensitive frame, rendered him in some
degree irritable and unsocial. He was not altogether
responsible for this ; but students of science should
recollect that diversity of occupations and interests is
subservient not only to bodily health, but also to men¬
tal equanimity and vigour.
The historian of science dwells with a special in- n^09;)
terest on the results of Ivory’s labours, when we re-
cal the singular destitution of higher mathematical tion as a
talent which had reigned in this country for so long a British Ma-
period, and which left us not only no position in the*.®”3*1'
great struggle going on abroad for the advancement
of physical astronomy, but scarcely even the rank of
intelligent spectators.
§ 4. Progress of Physical Astronomy since the publication of the Mecanique CeZeste.—POISSON.—
Theory of Rotation (Poinsot).—Mr Airy—T/te Solar Theory.—MM. Plana and Hansen—
The Lunar Theory.—Physical Astronomy in America.
(110.) The more that any theory of a mathematical kind,
tUfficult” oflik® Gravitation, advances to perfection,
physicafas-the less reason have we to expect great and striking
tronomy. results in the prosecution of it, and the more intense
and continuous is the labour in matters of detail ne¬
cessary to make any advance at all.
(111.) As regards the general and popular view of the
since^the88 subject, we might pass at once from the epoch of La-
publication grange and Laplace to that of Leverrier and Adams,
of the Notwithstanding, however, the necessity of extreme
^clleste^6 cornPressi°n' I must devote one short section to men¬
tioning the chief labours in connection with physical
astronomy of four eminent men mentioned in our title,
who may fitly be considered as the immediate succes¬
sors of Laplace. Two of them will be again referred
to in this discourse.
(112-) Simeon Denis Poisson, born in 1781, may be
Poisson gajq truly to have been brought up at the feet of La¬
grange and Laplace. He was their pupil in the first
and brightest years of the Polytechnic School, where
he was especially noticed by the former. He had
the distinguished privilege of being literally their
fellow-worker, his early memoirs having reference to
their labours, and stimulating the still vigorous mind
of Lagrange to the production, in his latest years, of
several memoirs, which have been considered worthy
of his best days. I refer more particularly to Pois-
TaVUty of son,s I)r0°f that the stability of the planetary system
the system; holds when perturbations of the second order are
taken into account, as has been stated in the first
section of this chapter, Art. (55.) This was in 1808.
Soon after, following out another of Lagrange’s ad¬
mirable generalizations of his theory of Arbitrary
Constants, he embraced in a common series of fpr-^0*3'
muhe the result of those mechanical laws which
regulate the rotation of bodies, together with those
concerned in their translation in space. This im¬
portant subject (rotation) continued at intervals to
engage the attention of Poisson, not only as re¬
gards the motions of the heavenly bodies on their
axes, but also as a branch of common mechanics.
The basis of this intricate doctrine was laid by Huy¬
gens ; Euler, in a celebrated and original work,
gave it a general and analytical form ; D Alembert
solved by it the problems of precession and nutation ;
Laplace demonstrated the constancy of the time of
the earth’s rotation round its axis. This last pro¬
blem was more fully discussed by Poisson, who showed
by theory that neither can the earth ever rotate round
an axis different from its present one, nor can the
time of its rotation vary in consequence of any ex¬
ternal attractions to which it is subject. These two
matters are of the utmost moment; the first prevents
the latitude of places from varying, and also renders
impossible the extensive flooding of dry land by the
waters of the ocean, which would be the evident con¬
sequence of such a change ; the second assui'es us
that the grand unit of reckoning in all ages, the tjie
basis of astronomical chronology and of physical mean soiar
astronomy generally, the length of the mean solar dag, day.
has not varied, and never will perceptibly vary under
the action of known forces. Laplace had long be¬
fore proved, by a comparison of ancient eclipses with
modern observations, that, practically, the length of
the day had not varied in 2000 years. It appears,
indeed, that since the earliest recorded Chaldean
1 See Biot in Connaisscmce des Temps,183d ; and Baily’s Life of Flamsteed.
Chap. IL, § 4.] PHYSICAL ASTRONOMY—MM. AIRY, PLANA, AND HANSEN.
825
eclipse (that of b.c. 720), the rotatory velocity has
not altered by one ten-millionth part.
P^'nsot em^nen^ contemporary and rival of Poisson, M.
on Rota- P°insot, has added many elegant propositions to the
tion. Theory of Rotation. M. Poinsot is also the author of
the Theory of Statical Couples, which now forms part
of all elementary treatises on mechanics.
(114.) Poisson wrote many other papers on subjects of
writings of physical astronomy, such, for example, as the Lunar
Poisson. Theory, hut they did not lead, on the whole, to strik¬
ing conclusions. In fact, he allowed himself to
he diverted from this his most natural calling, by
the ambition of constructing a system of Physics
mainly founded on the applications of analysis.
Some bulky volumes of this series appeared, espe¬
cially those on Capillary Attraction, and on the
Theory of Pleat. The author here shows him¬
self as a profound analyst, hut adds little to our
knowledge either of principles or of important re¬
sults. A similar criticism may he applied to his
theory of Elastic Substances, and to his doctrine of
Waves. His papers on Magnetism and Electricity will
he mentioned elsewhere, but their character is some¬
what similar. In Optics he was attached to the
Newtonian theory. In Mechanics not requiring as¬
sumptions as to the properties of matter, he was very
successful. He was eminently a solver of hard pro¬
blems : his investigation of the whole circumstances
of motion of a projectile in air deserves notice.
Indeed every branch of mechanics received his atten¬
tion, and the number of his printed papers is said to
exceed three hundred. On the whole, he will, per-
His Trea ^aPs’ mos^ generally and favourably known by the
tise on Me- exceHerd Treatise on Mechanics which he wrote for the
chanics. use of advanced students. He was an eminent and
diligent Professor, and his whole life was one of almost
unremitting study. “ La vie c'est le travail^ was his
reply, when urged to consult his health by reposing
from his labours : and he actually died in the dis¬
charge of his duty as examinator of the Polytechnic
School. This occurred on the 25th April 1840, in
the fifty-ninth year of his age.
Mr Airy on Airy on the perturbation by Venus of the
the pertur- Earth's motion.—We here detach from what we shall
the E*1 °th e^sew^iere have to record of the eminent services ren-
hy Venus ^ere^ to the cause of astronomy by the present As¬
tronomer Royal of England, a notice of his chief dis¬
covery in physical astronomy, the more remarkable
from being almost the only improvement in the theory
of the planetary motions, as applicable to the tables,
which had proceeded from an English mathematician
for a very long period. Sir James South called at¬
tention, in 1826, to a small but well marked devia¬
tion of the Sun’s place from that given by Delambre’s
solar theory (the Sun’s place or the Earth’s are of
course convertible terms). Mr Airy, then Lucasian
professor at Cambridge, instituted, in 1827, a more
extensive comparison with the Greenwich Observa-
VOL. i.
tions, and attributed the error chiefly to the assump¬
tion of erroneous masses for Venus and Mars. But
prolonged study satisfied him that it arose from a “long
inequality,” arising from the mutual action of the
Earth and Venus, similar in its nature to that men¬
tioned in Art. (66), as detected by Laplace in the
case of Jupiter and Saturn. It arises from the cir¬
cumstance that eight times the orbital period of the
Earth is almost equivalent to thirteen times that of
Venus. Terms of the series expressive of the mu¬
tual action of the planets, which are divided by thir¬
teen times the mean motion of the former minus eight
times the mean motion of the latter (which is a very
small quantity), may consequently become consider¬
able ; still more, those involving the square of this
quantity. Such terms belong to the fifth and higher
orders of the excentricity, and would consequently be
very minute indeed, but for the casual magnitude of
their coefficient. The labour of tracing out and cal¬
culating the effects of these important terms from the
vast mass of algebraic developments is enormously
great,—much greater than in the corresponding case
of Jupiter and Saturn. As the calculations are not
very likely to be repeated, Mr Airy took extraordi¬
nary precautions in their verification. The period
of the inequality depends, first, as has been explained
in Art. (67), upon the period required to carry the
point of conjunction of the two planets completely
round the circumference. This period is no less than
270 years. The perturbation is of course mutual,
and affects the place of Venus as well as of the Earth.
Mr Airy is also the author of investigations con- (n(5.)
nected with the Figure of the Earth, and the Theory
of the Tides [see Art. (82)]; and he has published va¬
luable Tracts on Physical Astronomy for the use of
students.
Sir John Lubbock’s name deserves mention here (117.)
as having devoted his energies, about the same time Sir John
with Mr Airy, to intricate and laborious researches Lubbock.
connected with the least inviting parts of physical
astronomy, and striven to redeem England from the
reproach of indifference or incapacity in respect of
such inquiries. The chief object of his numerous
memoirs (in the Philosophical Transactions for 1830,
and following years) is to express, in a more conve¬
nient and exact manner than had been in use, the
complicated serieses indicative of the perturbations as
well in the Lunar as in the Planetary Theory.
The Lunar Theory: MM. Plana and Hansen.— MALPkna
M. Plana, an astronomer and analyst of the greatest and Han-
merit, who fortunately still does honour to the nativesen on the
city of Lagrange (Turin), though the author of a great
number of Memoirs in the Transactions of the Turin e0ry*
Academy, on different points of Applied Mathema¬
tics, is, and will be, best known by his elaborate and
learned treatise on the Theory of the Moon. This
extends to three very bulky quarto volumes, which
are, so to speak, one mass of symbols. Nothing can
5 M
826
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
give a more impressive idea of the condition at which
Physical Astronomy has now arrived, than a glance at
this mountain of intellectual labour, — especially
as to the intricacy, inexpressible by words, of the
motions of our own satellite. Here we have a work, not
much smaller in appearance than the whole Mecanique
Celeste, devoted to this one object. It is not super¬
fluous to add, that this is no chimerical undertaking
 no curious puzzle—no learned trifling; the Lunar
Theory is the grand basis of the Art of Navigation.
The real and main use to mankind of our companion
planet is a discovery of these latter ages: her cheer¬
ful and beneficial light, which all appreciate, and all
enjoy, may almost be termed a secondary boon.
(119.) The merit of M. Plana is not so much that of
ofthe for- an original geometer, outstripping the theories of La¬
mer. place and Lagrange, as of a most intrepid and skilful
calculator, who has contrived to place in complete
order the whole mathematical and many of the arith¬
metical steps of the solution of one vast problem, ex¬
tending to some 2000 quarto pages. The calcula¬
tions he has made unaided ! The details are ar¬
ranged in so lucid a manner, as to court enquiry
from those interested in verifying them ; and though
the readers of so abstruse and indeed repulsive a
work must be few indeed, it has already proved
of essential service in the way which was intended
•—the improvement of the lunar tables. The ap¬
proximations by series are in all cases carried to
the fifth powers of small quantities, and, in some in¬
stances, to the seventh powers. Sir John Herschel
has expressed in forcible and picturesque language
the nature of what is wanting to the completeness
of Laplace’s investigations and which M. Plana has
supplied, as regards the theory of the moon’s motions:
•—“ In the Mecanique Celeste, we admire the elegance
displayed in the alternate interlinking and develop¬
ment of formulse, and exult in the power of the ana¬
lytical methods used; but when we come to the
statement of numerical results, we quail before the
vast task of filling in those distant steps ; and while
cloud rolls after cloud in majesty and darkness, we
feel our dependence on the conclusions attained
to partake of superstitious trust, or of amicable
confidence, rather than of clear and demonstrative
conviction.”1 The courage of M. Plana did not
“ quail” before the serried ranks of symbolic legions.
He attacked them first, and finally became their com¬
mander. But more than this ; on the same high
authority, “ his analysis is always graceful, his com¬
binations well considered, and his conceptions of the
ultimate results to be expected from them perfectly
just, and justified by the results when obtained.”
I may here mention that M. Plana, in conjunc¬
tion with M. Carl ini of Milan, undertook the calcula¬
tion of the moon’s motions from theory alone (that is, Lunar
with only the fundamental constants required to be Jable3
given by observation), in compliance with a pro-Theory
gramme issued by the French Academy of Sciences alone,
on the proposition of Laplace ; and that a French Carlini—
geometer, M. Damoiseau, on the same occasion, pro- amoiseau-
duced an independent investigation with very elabo¬
rate and valuable tables founded thereon.
M. Plana is the author of many other more (121)
circumscribed researches on important points in phy¬
sical astronomy, in geodesy, and in mathematical
physics.
M. Hansen, a German astronomer and analyst (122.)
of great merit, has made the most recent considerable Hansen,
improvement in the theory of the moon. We will
first, however, allude to an invention which is ap¬
plicable to the whole theory of perturbation.
We have seen, in the first section of this chap- (123.)
ter, that the effects of perturbation may be considered
either as applicable directly to the three co-ordinates perturba-
of the perturbed body, or to the variation of the ele- tions.
ments of the orbit considered as instantaneously va¬
rying ; that the former method has the advantage of
being in most cases, and especially in first approxi¬
mations, most direct; the latter is most applicable
to secular inequalities, and has a great recommenda¬
tion in the exact physical conceptions on which it is
founded. M. Hansen has proposed a third method,
a refinement, in fact, on that of Lagrange, in which,
by an assumption purely mathematical and arbitrary,
he throws the effect of perturbation entirely on the
element of time, so that with the time so altered, and
invariable elliptic elements, the conditions of pertur¬
bation may be satisfied, and the true place of the
body may result from the calculation. Such is the
general nature of the conception, which, to be carried
out, requires the introduction of subsidiary terms,
which serve to correct the latitude and radius vector.
The advantages which are understood to follow from
this highly artificial mode of proceeding are stated to
be (1.) that the serieses expressing the perturbation of
the co-ordinates are more convergent than in the
other methods, and likewise the coefficients of the
terms to be retained are more easily calculated; (2.)
M. Hansen considers that his method enables him
to ascertain with certainty those terms which, when
fully calculated, will affect the result in a sensible
manner. The inventor has applied his methods both
to the Lunar and to the Planetary theory.
We have said that physical astronomy is indebted (124.)
to M. Hansen for a notable improvement in the theory
of the Moon,—the discovery, in fact, of two inequali- equalities,
ties of long period, the existence of which had been
more than suspected from observation,but which were
1 Astronomical Society's Monthly Notices, vol. v., p. 37. The last expressions may astonish some persons, but experienced ana¬
lytical calculators agree in the same view. Mr Airy (probably the most competent authority in Britain) states the same thing
in many passages of his writings, to the effect that the evidence for conclusions so obtained is rather that of moral than of ma¬
thematical certainty.
827
Chap. II., § 5.] PHYSICAL ASTRONOMY.—M. LEVERRIER—MR ADAMS.
not accounted for. In the infancy of the lunar theory,
Euler had predicted that it would always he im¬
possible, on account of the perturbing forces of the
planets, to predict the Moon’s place within 30"; and
it was a quantity of about this measure which re¬
mained outstanding after all the resources of analysis
seemed exhausted. M. Poisson and Sir J. Lubbock
showed that the anomaly could not be due to the
solar action, nor yet to the irregularity of the Earth’s
figure. The planetary attractions, then, alone re¬
mained. M. Hansen discovered two independent in¬
equalities due to the action of Venus. One of these
is an indirect (or, as it is sometimes called, reflected')
effect depending on the change of form of the Earth’s
orbit by the attraction of Venus, which, of course,
modifies slightly the solar perturbation of the Moon’s
longitude. It is, in fact, a secondary consequence of
long inequality of Venus and the Earth investigated
by Mr Airy [Art. (115)], and has the same period,
namely, about 240 years. Its greatest amount is
23",2. The other inequality discovered by Hansen
is of a still more curious and complicated kind, which
goes on increasing for 2000 lunations, when it at¬
tains a maximum value of 27"'4 in longitude (al¬
though the perturbation of the radius vector does not
exceed 10 feet), after which it diminishes for an equal
space of time.
(125.) By these discoveries, the movements of our re-
His other fra(q,ory satellite may be considered to be, after an
wor s‘ unprecedented amount of labour, accounted for by
theory almost or quite within the limits of the pre¬
sent accuracy of observation.1 M. Hansen has re¬
cently been engaged in perfecting the practical details
of the lunar theory, in accordance with the extensive
reductions of the Greenwich observations which will
be mentioned in the next chapter. He has also given
the first complete theory of “ Foucault’s pendulum,”
also to be mentioned hereafter. Altogether, he
stands amongst the most eminent analytical astrono¬
mers of the present day.
We have in this section selected (though not by (126.)
design) representatives of the four great intellectual Gre”err^1g of
communities of Europe, engaged in the mighty task p^fsicli °
of perfecting the theories of physical astronomy. Astronomy
Poisson for France, Airy for England, Plana for
Italy, Hansen for Germany. It would be easy, of
course, to add the names of many others engaged in
similar works, and scarcely less deserving of notice.
Some of these will find a place in other chapters, and
we have yet one section of this chapter to devote to
the history of a discovery of rare interest, in which
France and England have a joint share. We may in Europe,
be allowed to mention the names of M. Damoiseau
and M. Pontecoulant in France ; the former known
by his excellent lunar tables deduced from theory,
the latter for his calculations of cometary perturba¬
tion, and his compendious treatise on physical as¬
tronomy, based on the Mecanique Celeste; in Italy,
MM. Carlini and Santini. But in Germany these
studies have been perhaps most systematically pur¬
sued. MM. Gauss and Encke have only not been
included in this section because we find it more suit¬
able to our plan to associate the name of the former
with his theory of Terrestrial Magnetism, and the
latter with the recent history of Comets. Bessel
likewise was a physical as well as first-rate prac¬
tical astronomer. I will here only add that these and in
severe and arduous studies have at length been America,
effectually cultivated beyond the limits of Europe.
Mr Bowditch (born 1773, died 1838), a private Bowditch.
gentleman of the United States, undertook the
gigantic labour of translating and illustrating, with
a complete commentary in which every difficulty is
considered, and every step of analysis supplied, the
Mecanique Celeste of Laplace. Since his death, a
younger race of American mathematicians has taken
up the great problems of physical astronomy, amongst
whom may be mentioned Mr Walker and Mr Peirce.
The latter gentleman has recently (1853) published
lunar tables, embracing the latest researches of theory.
5. M. Levebbieb—Mr Adams.—The inverse method of Perturbations. Prediction of the place
and orbit of Neptune from the motions of Uranus.
(127.)
The dis- We have now to chronicle a discovery which, by
covery of general consent, stands first in the achievements
from11116 sc^encej n°f; only In tlie period now under review,
theory by ^nt even in the long and eventful series of years
MM. Le- which have elapsed since Newton established the
Adams ^ ^oclrine of universal gravitation.
(128 ) The discovery of which we speak was no less
Its circum- than the proof of the existence of a planet beyond
stances. the recognised boundary of our system, merely as an
inference from the perturbed motion of the outmost
planet Uranus ; a proof, not general or abstract, but
particular and specific: “ Look, on such a night,
and in such a direction, and there you will see (by
the telescope) a star, small indeed, but with a distin¬
guishable disk,—that is the planet which has made
Uranus move so unsteadily in its orbit;”—so spoke
the mathematician ; and the zealous astronomer, to
whom the call was especially addressed, pointing his
glass to the sky, discovered at once, that is, the same
evening, a body answering almost 'precisely in position,
as well as in brilliancy, to the oracular announce¬
ment.
1 M.
Airy.
Hansen has also discovered the course of a small inequality of the Moon’s latitude, detected from observation
His theory of the Moon’s figure has been referred to in a note to Art. (o7.)
by
Mr
828
PHYSICAL ASTRONOMY.— M. LEVERRIER—MR ADAMS.
[Biss. VI.
(129.)
Its great
difficulty.
(130.)
(131.)
History.
(132.)
Since the publication of the Principia, or rather
we should say since the great theory contained in
that work had fully attracted the sympathies of
thoughtful and able men, nearly the whole science of
physical astronomy consisted in the solution of one
vast and intricate problem, which has been called the
“ Problem of the Three Bodies.” To this were bent
the powers of Clairaut, Euler, Lagrange, Laplace,
Plana, Hansen, and so many more. “ Let three
bodies be placed and move in a given manner in
space and attract one another by the Newtonian law,
to determine the motions as affected by their mutual
influence.” The problem solved independently by
the two analysts whose names stand at the head of
this section is this, “ Given two bodies (the Sun and
Uranus) and their relative motion, to find at any
moment the position of a third body whose attraction
shall be required to account for those motions.” To
have solved this new and far more difficult problem
(under certain limitations) is a triumph altogether
unlike in kind to any of the other brilliant successes
of which we have had to speak in the preceding
pages.
The great intricacy of the problem is not perhaps
at the first moment fully apparent. The pertur¬
bation of the known planet (Uranus) is not the
effect, either in direction or in amount, of the attrac¬
tion of the body sought, either at the instant, or at
any previous instant. It is an accumulated effect
arising from the totality of the mutual influences of
the two planets during a long space of time, and
under a variety of circumstances, which circum¬
stances it is the aim of the solution to discover.
But, more than this, we do not even know the quan¬
tity or direction of the perturbative action at any
moment for which the cause is sought, for we do not
know the purely elliptic elements of Uranus. His
motion has, by hypothesis, been always troubled by
this exterior planet, and Uranus has been so short
a time known and observed (only accurately since
1781) that the motion has not yet been cleared of
ordinary inequalities (due to the action of the unseen
body), which, therefore, are inextricably mixed up
with the elliptic elements. It is absolutely necessary,
therefore, to suppose not only the elements of the
new planet to be unknown, but also the elements of
Uranus to be severally affected by unknown errors.
This nearly doubles the unknown quantities to be
found.
We shall now glance at the history of these un¬
explained perturbations, and at the rise and growth of
the idea of their being explicable by the influence of
an unseen body.
After Sir W illiam Herschel had discovered, in
1781, the planet which he called Georgium Sidus, Irregulari-
(afterwards named Herschel, and finally, by general ties of the
consent, Uranus,) it was easy, by a few observations, ™0tl0n8 of
to ascertain its approximate orbit and distance from
the sun. But the extreme slowness of its motion
(it will not have completed a single revolution before
1861) made it impossible to determine its elements
with precision, until it had been discovered that the
records of astronomy contained about twenty observa¬
tions of this body before its planetary nature was
discovered; being, in fact, registered places of fixed
stars where no stars exist, concurring in brightness
and position with the circumstances of Uranus at
those remoter periods; the earliest of these obser¬
vations was one of Flamsteed, in 1690. The first
person who constructed tables of the planet was De-
lambre ; but even at that early period, it was re¬
marked, that the modern were not satisfactorily recon¬
cilable with the ancient observations; and, finally,
Delambre included of the latter only one, by Mayer,
which he did, he tells us, “ out of pure respect,” al¬
though it certainly rendered the tables less exact and
less durable. The longer the planet was observed,
and the greater the care that was expended in analys¬
ing and combining the observations, the more clearly
it appeared that the tables had only an empirical cha¬
racter, satisfying observations for a few years before
and after the time for which they had been con¬
structed ; and that, in particular, as the nineteenth
century advanced, the deviations from elliptic regu¬
larity became more and more intolerable, till the “ an¬
cient” observations were at length totally given up.
This was the state of matters in 1821, after M.
Bouvard of the Observatory of Paris, a most able cal¬
culator, had exhausted every resource in improving
the Tables of Uranus. A few years more gave that
patient astronomer the mortification of seeing his
tables as obsolete as those of his predecessors, and nu¬
merous surmises were circulated as to possible expla¬
nations of the anomaly: a failure in the law of gra- Hypotheses
vity, cometary perturbation, a resisting medium,
and, finally, the presence of an unseen planet, were
amongst these guesses. The last and most plausible
of these hypotheses occurred to many; amongst
others, to Mr Hussey in England, M. Bouvard in
France, and later to M. Bessel in Germany.1 The
first of these astronomers actually consulted Mr Airy,
in 1834, on the possibility of predicting the place of
the perturbing planet from theory, and then disco¬
vering it by observation. Mrs Somerville, in 1836,
gave a precise expression to the same idea.2 From
this time the subject could not be lost sight of. The
errors of the tables which in 1821 were insen¬
sible, increased in 1830 to 15" or 20", and in 1845
1 Clairaut, nearly a century before, in calculating the return of Halley’s comet, hinted at the possible perturbation due to a
planet superior to Saturn.
2 In her Connection of the Physical Sciences.
Chap. II., § 5.] PHYSICAL ASTRONOMY.—M. LEVERRIER—MR ADAMS.
829
(133.)
M. Lever-
rier’s inves
ligations;
amounted to two minutes of longitude. M. Bouvard
to his latest years, perhaps his latest hours,1 che¬
rished the hope of extricating this theory from its
difficulties. He also engaged his nephew M. Eugene
Bouvard in the same career, who appears to have
followed it with much zeal and intelligence, and
in 1845 constructed new tables of Uranus. But by
this time two geometers had separately and inde¬
pendently undertaken the problem, with the deter¬
mination of finding, if possible, a physical solution
of all this perplexity. The earliest in point of date
was Mr Adams, a young graduate of Cambridge; the
other was M. Leverrier of Paris, whose attention
was directed to the subject by M. Arago. As the
researches of M. Leverrier, though second in point of
time, occasioned the actual recognition of the planet,
and thus stamped the correctness of the solution with
success, we shall consider them in the first instance.
M. Leverrier is, we believe, a native of St Lo
in Normandy, a province which has been singularly
productive of eminent men (Laplace and Fresnel
were of the number). With no advantages, but the
reverse, he won a high position at entering the
polytechnic school, which he constantly maintained.
He at first, we believe, attached himself to chemis¬
try, but his taste for physical astronomy was soon
developed, and was advanced entirely by his private
efforts. It is a peculiarity of the mode of culti¬
vating the sciences in Paris, that such abstruse
and difficult studies are not merely engaged in tem¬
porarily for purposes of academial distinction, but that
they actually become a “ carriere” or calling, and are
pursued in that methodical manner for which the
French are distinguished. In 1845, when he com¬
menced the careful examination of the theory of
Uranus, M. Leverrier was already favourably known
by his researches on comets, and on the orbit of
Mercury,but especially by immense calculations, con¬
nected with the secular inequalities of the planets, by
which his ability and hardihood in computation had
been thoroughly exercised. He began his new en¬
quiry with the method and intrepidity of calculation
which distinguish him. He revised with the most
minute care the observations of Uranus, and
computed afresh every sensible perturbation which
theory recognised as arising from known planets.
This done, and having compared the most probable
orbit with observations which he collected from
authentic sources, and especially from the Greenwich
observations which were communicated to him for
this purpose, the result was, that even confining
himself to observations since 1781, arranged in
eleven convenient groups (each resulting from many
observed places), and attributing to each group the
largest error which could be in reason allowed,
and even admitting that all these errors were in the
direction most favourable to the assumption, it was
still impossible to account for more than one-fourth
part of the observed discordances.
M. Leverrier then assumed that a perturbing (134.)
planet existed beyond the orbit of Uranus, and at
nearly double its distance from the sun, in conformity
with the empirical law, (usually attributed to Bode
the German astronomer,) which expresses with gene¬
ral accuracy, thus far, the arrangement of the planetary
system. The law is, that the distances of the planetary
orbits from Mercury are successively doubled. This
assumption—(it was absolutely necessary to assume
some distance to begin with)—was ingeniously con¬
firmed by other considerations.
Leaving the perturbations in latitude out of ac- (135.)
count, he now considered each error of Uranus in
longitude as the expression of a perturbation due
to the action of the unknown planet, and capable
therefore of algebraic expression in terms of the ele¬
ments of that planet, namely its excentricity, longi¬
tude of perihelion, epoch in its orbit, and mass ; but,
as we have already remarked, the first three of these
elements must be considered as incorrectly assumed
for Uranus itself, as well as the mean distance of that
planet, and, therefore, there are four unknown correc¬
tions for its elliptic elements,making in all eight quan¬
tities to be eliminated from the discordances of theory
and observation. So complex an elimination cannot
be directly effected ; and even if it could, the result
could not be depended on, as the possible error of
each observation involves a fresh and important
source of doubt in the conclusion. M. Leverrier
proceeded, by a series of gradually restricted assump¬
tions, to find within what limits the more important
elements might be made to vary without producing
effects incompatible with observation, and his atten¬
tion was at first confined to the approximate mean
longitude of the planet. He obtained a result after Their re-
a prodigious amount of tentative calculation. The sult*
excentricity and position of the perihelion were then
inferred. On the 1st June 1846 he announced to
the Academy of Sciences that the true longitude of
the expected planet for 1st January 1847 was 325°,
with a probable error of 10°. This result was im¬
mediately published in the Comptes Rendus.
Between the 1st June and 31st August 1846, (136.
when his third memoir on the perturbations of Lever-
Uranus appeared, M. Leverrier busied himself in ob-
■i-*- ' #t a<^IlOUIlG6,•
taining a farther approximation to the elements and ment;
place of the suspected planet. He now assumed the
correction of the mean distance amongst the other
quantities to be sought. By a fresh calculation he
1 M. Bouvard was born in 1767. He performed almost all of the numerical calculations required by Laplace in his great
work, and was associated with that eminent man by the most friendly ties. He “ ceased to calculate and to live” 7th June
1843.
830
PHYSICAL ASTRONOMY.—M. LEYERRIER—MR ADAMS.
[Diss. VI.
deduced a complete list of elements as regards longi¬
tude ; and diminished the mean distance considerably.
The true longitude by this calculation differed only
1£° from his previous estimation. He finds for the
mean distance from the Sun 36 times that of our
Earth (that of Uranus being 19), the period 217
years, and the mass of the Sun’s. Assuming
the density of the planet to he the same as that of
Uranus, he conjectures that the apparent diameter
will he ; that it will therefore have a visible disk
sufficient to distinguish it from a fixed star, and that
its brilliancy should equal that of a star of the 8th
or 9th magnitude. As the result of these supposi¬
tions, he found that the whole errors in the places
of Uranus from 1781 to 1844 were reconciled within
quantities amounting but in one instance to 5" ; that
the ancient observations of the 18th century were
reconciled within 7" or 8" ; and the oldest observa¬
tion of all, that of Flamsteed in 1690, had an out¬
standing error of 20", a quantity very far from exces¬
sive, considering the state of astronomy at that period.
(137.) No one who read at the time the abstract of this
resulting in remarkable paper in the Comptes Rendus failed to
ver/of °* ^6 struck with it, not only as regarded the weighty
Neptune by matter, thus publicly announced, but also on account
M. Galle. 0f the calm and well-grounded conviction which the
author manifested in the truth of his hold conclusions,
and the definite manner in which he gives the chal¬
lenge to practical astronomers to verify or disprove
them. “ Since Copernicus declared” (according to the
prevalent tradition) “ that when means should he dis¬
covered for improving the vision, it would he found that
Venus had phases like the moon, nothing,” writes Mr
Airy, “so bold, and so justifiably bold, has been uttered
in astronomical prediction.” M.Leverrier had hastened
his calculations in anticipation of the approaching
opposition of the new planet in the autumn of 1846,
hut it is very doubtful whether astronomers would
have made the discovery at that time, but for his per¬
sonal application to M. Galle, then assistant-astro¬
nomer at Berlin, where a powerful refractor suitable
for the search existed. So ardent a conviction in a
manner compelled the proof which the geometer
claimed, and M. Galle, whose intelligence and zeal
are well known, pointed his telescope to the shy the
very evening that M. Leverrier’s letter reached him.
Fortunately provided with a newly published star
map by Brenicker of that region of the heavens, which
was not at that time diffused generally amongst
European observatories, he detected that same night
(the 23d September 1846) a star-like body of the 8th
magnitude, not noted in the star chart, therefore a
wandering body, having a manifest disk from 2J" to
3 in diameter, and distant only fifty-four minutes of
a degree from the predicted place.
(138.) It will be remarked that the discovery in question
was anticipated and completed in France and Ger¬
many alone; England had no direct participation. We
must now, however, state briefly what occurred there of
a similar character at the same time, and even earlier.
Mr John Couch Adams, when a student at St (139.)
John’s College, Cambridge, in 1841, formed the de¬
sign of detecting the position of a perturbing planet
which should account for the anomalous motions of
Uranus. Fie made a preliminary essay on the pro¬
blem in 1843, assuming the distance of the suspected
body from the Sun to be double that of Uranus.
I learn from good authority that he obtained a place
for the unseen planet not very different from that
which he finally adopted. Early in 1844 he ob¬
tained from Greenwich the valuable series of places
of Uranus which were afterwards in like manner ap¬
plied for by M. Leverrier. In September 1845, he
communicated to Professor Challis the elements of the
new planet’s orbit (neglecting the inclination) and an
ephemeris of its geocentric place; and in October he
transmitted the elements alsotothe Astronomer Royal. Mr Adams
This, it will be observed, was soon after M. Leverrier’s preceded
attention was first directed to the subject, and nine r/r
months previous to his announcement of the locality similar in-
where the new body should be sought. Mr Adams yestiga-
afterwards repeated his calculation with a mean dis-tlon ’
tance ^gth less than before, and considered himself
warranted, by the improvement thus produced on the
residual errors, in inferring that a farther consider¬
able diminution of the mean distance would satisfy
the observations still better. This was communicated
to Mr Airy on the 2d September 1846 ; subsequently
therefore to the publication of M. Leverrier’s Ele¬
ments. Mr Adams, in communicating his results (at
a later time) to the Astronomical Society, with charac¬
teristic modesty says, “ I mention these dates merely
to show that my results were arrived at independently,
and previously to the publication of M. Leverrier,
and not with the intention of interfering with his just
claims to the honors of the discovery, lor there is no
doubt that his researches were first published to the
world and led to the actual discovery of the planet by
Dr Galle.”
And such is no doubt the fact. The priority of Mr (1^0-)
Adams m the mathematical investigation is as certain net was not
as that the researches of M. Leverrier alone produced discovered
the discovery of Neptune. Even the search for the in conse-
planet which took place in August and September (lueI1Ce•
1846 at Cambridge by Professor Challis, was not oc¬
casioned by Mr Adams’ researches only ; it was the
near coincidence of the longitude assigned by Mr
Adams in the previous October with that published
by M. Leverrier in June 1846 which induced Mr
Airy to suggest this investigation of the heavens,
and to oiler (if need were) himself to bear the ex¬
pense. Had the planet been discovered1 at Cambridge
The planet was indeed seen at Cambridge by Mr Challis, for it was recorded more than once amongst the numerous fixed
sars whose places were taken down in the progress of the search; but as the comparisons of the “ sweeus” were not made at
the time, the discovery was anticipated by M. Galle. A
Chap. II., § 5.] PHYSICAL ASTRONOMY.—M. LEVERRIER—MR ADAMS.
831
before it was at Berlin, M. Leverrier must still have
bad a share in the credit of success.
(141.) It is perhaps to be regretted that Mr Adams had
Remarks not given his whole investigation to the world, or
on the his- published his results, so as to avouch the
tor^' confidence which he felt in his own prediction, and
to throw upon practical astronomers generally the re¬
sponsibility of its verification. Had he done so in
1845, it is 'possible that the planet might have been
discovered at the opposition of that year ; but it is at
least certain that M. Leverrier’s claims to priority
as regards the discovery of Neptune would have
been effectually anticipated. But it is only just to our
countryman to recollect the difference of his age and
position. M. Leverrier was at the time about 35
years of age, and was a candidate for the sub¬
stantial benefits as well as for the honour of a mem¬
bership of the Academy of Sciences. Mr Adams
must have been nine or ten years younger at the
period of this discovery, a circumstance which en¬
hances our admiraion at the achievement, whilst it
gives an additional grace to the modest conduct of
the author.
(142.) I have endeavoured to state correctly (with due re¬
gard to the limits of this essay) the main facts of the
most curious case of double discovery which, perhaps,
the history of science presents ; and happily as to the
facts, down to the minutest detail, no discrepancy of
opinion ever existed. Different minds will, with per¬
fect truth, attach more or less distinction to the two
illustrious rivals,—neither of whom has for an in¬
stant lowered the dignity of his position by one
ungenerous expression,—but that the absolute merit
of both is of the very highest character is on all
hands admitted. “ The names of M. Leverrier and
Mr Adams,” said Sir John Herschel, addressing the
Astronomical Society, “ which Genius and Destiny
have joined, I shall by no means put asunder ; nor
will they ever be pronounced apart so long as lan¬
guage shall celebrate the triumphs of Science in her
sublimest walks.”
But before closing, I must briefly state how far
the orbit of the planet Neptune, when discovered, vatjon 0f
realized the previsions of theory. A fortunate cir- Neptune as
cum stance rendered it easy to obtain at an early a fixed star-
period a correct knowledge of the elements. It seems
that the planet Neptune was observed by Lalandeat
Paris on the 8th and 10th May 1795, and entered
as a fixed star, notvjithstanding a distinct change of
place between the observations, actually corresponding
to what the planet should have had.1 But such an
oversight had been made by Lemonnier in the case
of Uranus. By means of this observation of fifty
years back, the orbit was easily computed. It is a
singular and startling fact, that, except as regards the
longitude on the orbit, the other elements computed
from observation were somewhat widely different
from those assigned by M. Leverrier and Mr Adams.
We shall present them in a tabular view. The value
of the mass in the last column is calculated from the
elongation and period of a satellite of Neptune dis¬
covered by Mr Lassell.
Epoch of Elements,
Mean Longitude,
Mean Distance,
Period,
Long. Perihelion,
Excentricity,
Mass, .
Theory—Leverrier.
1st Jan. 1847,
318° 47'
36-15
217'4 years
284° 45'
0-1076
Anr of Sun s
Theory—Adams.
6th Oct. 1846,
323° 2'
37-24 2 3
299° IP
0-1206
b-tVts
Observation— Walker.
1st Jan. 1847.
328° 33'
30-04
164-6
47° 12'
0-00872
1 3
(144.) The differences of theory and observation are so
striking as to have occasioned surprise to many per¬
sons that, with data so erroneous, the perturbations
of Uranus or the longitude of Neptune at the epoch
of discovery should have been obtained even approxi¬
mately.
(145.) The fact, however, is this :—that the mutual per-
H°w811 as- turbations of Uranus and Neptune are sensible for
erroneous^ orily a small portion of the joint orbits when the
elements planets are nearly in conjunction. The conjunction
led to the (\vhen the mutual distance is least and the attraction
iscovery j strongest) took place in 1822. Now the places of
Uranus from 1690 (the first observation) until 1800
can be sufficiently well represented by elliptic ele¬
ments. The perturbation of Neptune became sen¬
sible therefore only twenty years before conjunction.
In this time Neptune describes (really) only ^ of a cir¬
cumference, or 45°, and relatively to the motion of
Uranus about the same. It is evident then that
even a considerable error in the period of Neptune
would scarcely sensibly affect the law of perturba¬
tion during twenty years, and that the approximate
determination of the place of the perturbing planet
about the time of conjunction will not be much
affected by the error of that assumption. Again,
as to the error of mean distance, we may observe,
that since the mutual action of the planets is
confined within such (comparatively) narrow limits
of space and time, though wre might anticipate a toler¬
able approximation to the interval between the bodies
1 One of the observations was suppressed in the publication, and only discovered on searching Lalande’s MS.
2 This was the hypothesis upon which Mr Adams made his second or corrected calculation of elements. Nevertheless, he
inferred from that calculation that the mean distance might with much probability he reduced to 33-4.
3 Pierce. Struve’s mass is
832
[Diss. VI.
ASTRONOMY.—MASKELYNE—DELAMBRE.
at that time, \t would be unreasonable to expect a
correct determination of the form and ellipticity of the
orbit of Neptune, such as might belooked forif theper-
turbations were sensible through the entire orbits; and
in fact, by varying the position of the perihelion and
the amount of excentricity, we may, for an assumed
mean distance, obtain any value whatever for the in¬
terval of the two planets at a particular time. We
have seen the origin of the false assumption of mean
distance on the part both of M. Leverrier and Mr
Adams, and we find that the mathematical solution
corrects to a great extent the error of that assump¬
tion by giving a correspondingly incorrect position of
the perihelion, and also an exaggerated measure of
the excentricity, by which two circumstances the
planets of both mathematicians would have had, near
the time of conjunction, a distance from the sun of
only 32 or 33 radii of the earth’s orbit, the true dis¬
tance being about ^ part less. This still remaining
error was palliated, and evidently might for a time
have been completely masked, by assuming a mass of
Neptune proportionally too great, as indeed the table
we have given shows was the case.
(146.) That the discovery of Neptune took place at the
the1 (Tsco t'me when it did was no accident. The conjunction
very took °f Uranus and Neptune, when alone the perturbation
place when of the elliptic elements is perceptible, is a rare phe-
it did. nomenon, occurring but once in about 172 years.
The last conjunction previous to 1822 was in 1649 :
we have seen that the attention of astronomers was
importunately called to the subject by the irregu¬
larities in the motions of Uranus at the first con¬
junction succeeding its discovery.
(147.) We are indebted to Professor Peirce and Mr
Walker of the United States for many useful inves- Principal
tigations connected with the orbits of Uranus and inequality
Neptune ; but it is to be wished that the theory were ®^^aenus
completely re-examined, and also the problem of the tune*
inverse method of perturbations which has now be¬
come a systematic portion of physical astronomy.
The near commensurability of the two periods pre¬
sents a peculiar case of perturbation similar to the
long inequality of Jupiter and Saturn ; but as its
period is no less than 4047 years,1 although the
coefficient of the inequality is considerable, it will
not perceptibly alter the motions of either planet
except in a long course of years.
It will not be supposed that either M. Leverrier or (148.)
Mr Adams could, after such a memorable triumph, Other
abandon the pursuits of physical astronomy. The ^i^dLis
first has continued his researches on the orbits of an(i'Lever-
comets and on the perturbations of the solar system ; rier.
and having been recently appointed to succeed M.
Arago in the direction of the Paris Observatory, we
cannot doubt that he will infuse new life into its
management. Mr Adams has made the discovery of
some important oversights in the details of the lunar
theory. One of these, with reference to Laplace’s
Theory of the Secular Acceleration of the Moon’s
mean Motion, has been referred to in a note to Art.
(62). Though Mr Adams occupies no public post, and
though he has declined the honours of a title, his con¬
tinued residence at Cambridge must influence very
beneficially the studies of the place, where some of
his many friends have founded in memory of his
achievements a perpetual prize for the advancement
of physical astronomy, which is denominated the
Adams Prize.2
CHAPTER III.
ASTRONOMY.
§ 1 Maskelyne—Delambre.—Progress of Practical Astronomy from 1770 till 1810—Of the
Lunar Theory deduced from Observation—The Density and Figure of the Globe. Cavendish ;
Baily. Trigonometrical Surveys.
(149.) As examples of those astronomers who most contri- whether of the motions of the heavenly bodies or of
Practical buted in the period of which we now principally speak the figure and density of our own planet, I have se-
KZO-lsTo (1770-1810) to the progress of exact observation, lected Maskelyne and Delambre. Their characters
1 According to the calculations of M. Peirson (Camb. Trans, vol. ix.).
2 It has been our business to condense the history of the discovery of Neptune within a compass proportioned to the general
scheme of this Dissertation. The reader who desires farther details will consult M. Leverrier’s Memoir on the Perturbations of
the Herschel planet (Uranus) in the Connaissance des Temps for 1849 (also published separately), and in the Comptes Rendus for
1846; Mr Adams’ papers in the Nautical Almanac for 1851, and the Astronomical Society’s Memoirs, vol. xvi.; Mr Airy’s singularly
curious and impartial Historical Account in the 7th vol. of the Astronomical Society’s Monthly Notices ; M. von Lindenau’s History
in Schumacher’s Nachrichten (Erganzungsheft) (favourable to M. Leverrier) ; Grant’s History of Physical Astronomy (advocating
principally the claims of Mr Adams). Sir J. Herschel’s Outlines of Astronomy contain a very valuable description of the scientific
part of the question.
Chap. III., § 1.]
ASTRONOMY.—MASKELYNE—DELAMBRE.
833
were both distinguished by modesty, simplicity, and
love of truth. Of all their contemporaries of emi¬
nence, few escaped so happily from the unprofitable
strife of rivalry and personal disputes, and none ex¬
hibited a more impartial desire for the advancement
of the science to which they were devotedly attached.
Perhaps neither was a man of lofty talent, yet they
did not fail to secure deserved respect in their own
day, and far more gratitude from the posterity whom
they essentially benefited than falls commonly to
the share of men of higher pretensions in this re¬
spect. Both their names are important links in the
history of astronomy.
(150.) Nevil Maskelyne, born in 1732, and educated at
Maskelyne; Cambridge, was early attached to astronomical pur¬
suits. After various minor services connected chiefly
with navigation and the discovery of the longitude, he
attained the honourable post of Astronomer Royal,
w hich he filled from 1765 till 1811 with distinguished
success. His immediate predecessor was Dr Bliss, who
held the office for but three years and without dis¬
tinction. Practically, Maskelyne may be said to have
succeeded Bradley, probably the greatest astronomer
wffiom England has yet seen, whose discoveries have
been recorded in the last Dissertation, and whose
observations, through a variety of circumstances, were
destined rather for the benefit of the nineteenth cen¬
tury than for his own. Maskelyne wisely recollected
that the observatory was mainly founded for the
improvement of navigation,1 2 and one of his earliest
labours was the establishment in 1767 of the “Nau¬
tical Almanac,” a work based on the best astronomi¬
cal observations and of the highest service to seamen.
“ During Maskelyne’s long tenure of office he was
entirely devoted to its duties, making himself all the
most delicate observations, particularly those of the
moon, and rarely quitting the observatory except to
attend the meetings of the Royal Society. The per¬
fect method and continuity of his observations give
to them a great value, especially for the correction
of the Lunar Tables, in which respect they are indeed
without a parallel. But the regularity of their
publication was not their least merit. Four large
folio volumes include the patient labours of a life
(for he had but one assistant). Delambre in his
character of Maskelyne says, that if through some
catastrophe the whole materials of science should be
lost, except these volumes, they would suffice to re¬
construct entirely the edifice of modern astronomy.’,2
hisobser ^ac^’ on Maskelyne’s accession, the only methodi-
vations at ca^ publication which had issued from Greenwich
Greenwich. Observatory was the “ Historia Celestis” of Flam¬
steed ; Halley’s, Bradley’s, and Bliss’s observations
remained in manuscript. A like fate attended most
of the foreign astronomical observations ; labours
the most irksome and conscientious lie buried in
piles of MS. useless to science, and which therefore
might almost as well have never been made. This
is particularly the case with the Parisian observa¬
tions (as the impartial Delambre records with pain),
commenced even before the time of Flamsteed ; but
which, owing to this cause principally, have remained
even to the present day (and it is forty years since
Delambre wrote his patriotic protest) without con¬
tributing materially to advance astronomy. Let it
then be recorded to the honour of Maskelyne, that
this important step of regular and full publication
at the public expense was entirely due to him. His
places of the sun, moon, and planets, were the founda¬
tion of the improved theories of physical astronomy,
then more ably cultivated on the Continent than in
Britain, and of the tables also chiefly furnished by
German and French computers.
Maskelyne’s more important contributions to
science may be briefly stated under these two heads ;
—The determination of the Lunar orbit from observa¬
tion, and its application to navigation ; and the de¬
termination of the local attraction of Schehallien and
of the density of the earth.
I. The determination of the Lunar Orbit from Ob¬
servation and its application to Navigation.—Though
astronomy owes (as we have already said) much to
Maskelyne in the exact determination of the places
of the sun, planets, and the most conspicuous fixed
stars, the comparison of the Lunar place with the
tables was by far the most arduous and the most im¬
portant of his undertakings. It was the most ardu¬
ous, because, from the extreme complexity of the
moon’s motions, every part of its orbit must be nar¬
rowly watched, requiring the astronomer’s presence
at his instruments at all possible hours during the
course of a lunation, these motions being subject to
important changes which recur every nineteen years,
besides others of yet far longer duration. It was
Maskelyne’s good fortune, and at the same time the
reward of his perseverance, to watch three revolu¬
tions of the lunar nodes. He did not content him¬
self, however, with making observations ; he contri¬
buted in every possible way to the improvement of
the tables of the moon’s motion. He was in con¬
stant communication with Mayer, one of the ablest
astronomers of his day, and he directed the calcula¬
tion of Bradley’s observations by Mason, for the far¬
ther improvement of Mayer’s Tables. Maskelyne’s
own observations, to the number of at least 5000,
were used by Burg in his excellent tables of the moon
which have even yet been hardly surpassed; but
their full value has only been tested recently by the
1 In the warrant appointing Flamsteed to be the Royal “ Astronomical Ohservator,” his duty is declared to he “ to rectify the
tables of the motions of the heavens and the fixed stars, so as to find out the so much desired longitude at sea, for perfecting the
art of navigation.”
2 From an article on Greenwich Observatory in the Edinburgh Review, written by the author of this Dissertation.
VOL. I. N
(151.)
(152.)
Lunar ob¬
servations.
834
ASTRONOMY.—MASKELYNE—DELAMBRE.
[Diss, VI.
(153.)
The Nau¬
tical Alma¬
nac.
(154.)
Attraction
of moun¬
tains.
systematic reduction of all the lunar observations of
Maskelyne and Pond, and a comparison with Damoi-
seau’s tables, under the direction of the present As¬
tronomer Ro)ral, Mr Airy.
But, for the application of the method of lunar
distances to navigation, farther aid than the con-
' struction of good tables was required. This Maslce-
]yne provided by obtaining the regular publication
of the Nautical Almanac, superintended by himself,
and containing the distances of the moon from the
principal fixed stars at predetermined hours for the
meridian of Greenwich, a comparison of which with
the distance observed by means of the sextant in any
part of the world enabled the seaman (after proper
reductions) to infer the exact GreenvAch time of the
observation, and thence, by comparison with the local
time obtained by the usual methods, to obtain his
longitude. To this, long admitted to be the best
practical solution of the celebrated problem of “ the
longitude at sea,” Maskelyne contributed probably
more than any other person. His “ Lunar Distances”
were reprinted in the French Almanac (Connaissance
des Tews) for a considerable number of years.
II. The determination of the Attraction of Sche-
hallien, and of the Earth’s Density.—The deviation
of the plumb-line from the vertical by the neighbour¬
hood of a mountain had been pointed out by Newton1
as a direct consequence, and also as a test, of the
principle that gravity resides in every part of the
earth as well as in the earth as a whole. Bouguer
had the merit of pointing out the form in which the
experiment might be made, and of making the trial,
though in a rude and insufficient manner, in the
Peruvian Andes in 1738. He observed the effect of
the mountain on the south side only, but at two sta¬
tions unequally distant from its centre of attraction.
The numerical result being (as the author himself
admitted) without value, Maskelyne proposed to the
Royal Society in 1772 to repeat the observation on
some British mountain. A “ Committee of Attrac¬
tion” was named, which, besides Maskelyne, included
Cavendish, Franklin, and Horsley. Cavendish, as
might have been expected, took an earnest part in it.
The search for a suitable hill was confided to Mr
Charles Mason in 1773. Skiddaw and the York¬
shire Hills were first thought of, but finally Sche-
hallien in Perthshire was preferred.2 3 Thither Mas¬
kelyne himself proceeded in 1774, with his assistant
Burrows, and by these two, with the aid of a local
land-surveyor, the labour of the astronomical and
chief geodetical operations, including the measure¬
ment of two base lines, was effected between the 30th
June and the 24th October, notwithstanding the
hindrances of a most unfavourable season.
The distance between the two stations obtained with (155.)
Ramsden’s 9-inch theodolite, was 4364-4 feet, which Maske-
in the latitude of Schehallien corresponds to 42"-94 gervations
of latitude. The observed difference of latitude by at Schehal-
337 observations with Sisson’s 10-feet zenith sector lien-
was 54"-6.3 The excess, orll"-6, is the double at¬
traction of the hill drawing the plumb-line towards
itself at the two stations. The sine of this angle, or
represents the actual ratio between the double
attraction of the hill and the attraction of the earth.
But by the computation of the attraction which the
hill ought to exert, from its figure, as determined by
Maskelyne’s gauges, were its density the same as that
of the globe generally, this ratio should amount to
which can only be accounted for by assuming
the earth to be denser on the average than the hill
of Schehallien in the proportion of 17804 to 9933.
This deduction was made by Dr Hutton by means of
a troublesome calculation of the summation of the
attractive effects of a number of vertical prisms into
which the hill was imagined to be divided. The arti¬
fices of calculation were, however, due to Cavendish
(who it will be recollected was on the “ Committee of
Attractions,”) as Mr Airy ascertained from his manu¬
scripts. A careful lithological survey of the hill Earth’s
enabled Professor Playfair to deduce the probable ^jensity de'
mean specific gravity of the globe to be between 4-56
and 4-87, which was somewhat greater than Dr
Hutton assumed it.
This is the proper place to mention an experiment (156.)
on the density of the Earth perhaps still more re- Ml^hpI1ven
markable, devised by the Rev. Mr Michell, who con- ^sh’sexpe-
structed the apparatus, but first put in practice by riment for
Mr Cavendish in 1797-8. It consisted in measuring the same
the force of gravitation between two spheres of such end‘
small size that they could be moved by the hand
nearer to or farther from one another. The essen¬
tial part of the invention was to contrive a balance
so delicate as to measure the almost inappreciable
tendency of such small bodies to unite. Newton had
shown that the attraction at the surface of any sphere
is directly as its radius, which he observed must
always be incomparably smaller than their tendency
towards the earth, that is, their weight. In the
largest and heaviest masses with which it has hither¬
to been found practicable to operate, this tendency
1 De Mundi Systemate, § 22. Newton, in a very remarkable passage of the Third Book of the Principia (Prop. X.), con¬
jectures that “ the quantity of matter in the earth may be five or six times greater than if the whole were composed of water.”
A laughable mistake of Zach in his account of the Schehallien experiment (in his Attraction des Montagues) is commented
on by Playfair in the Edinburgh Review. In a note to the word Schehallien, Zach says, “ Montague appelee dans le pays en
langue Erse Maiden pap, qui veut dire orage perpetuel.” It is needless to add that these two alleged synonyms are different in¬
terpretations given by Gaelic scholars of the word. “ From this inaccuracy,” adds his reviewer, “ his residence in London
ought to have delivered him, for though he could not learn there what was Erse, he might have learned what was English.”
3 Zach obtained the same result exactly by including all the observations, as Maskelyne had provisionally obtained by using
only those stars on which he most depended.
Chap. III., § 1.]
ASTRONOMY.—MASKELYNE—DELAMBRE.
835
amounts to only a very minute fraction of a grain.
How could such quantities be accurately estimated, so
as not only to leave no doubt of the phenomenon of
gravity thus acting on the small scale, but to deduce
its amount, and hence to weigh the globe 1
(157.) Mitchell imagined for this purpose the balance of tor-
Balance!10n •9Z'on’was re-invented by Coulomb (who probably
first executed it) for the purpose of measuring electrical
forces. Mitchell’s apparatus came first into the hands
of Wollaston, then of Cavendish, who made the experi¬
ment. He used a very light rod of deal, six feet long,
suspended by a fine silver or copper wire, forty inches
long, within a wooden case to defend it from currents
of air. At each end of the lever was hung a hall of
lead, two inches in diameter, and by a simple con¬
trivance a pair of leaden spheres, weighing, together,
348 pounds, could be brought simultaneously into
the neighbourhood of the balls (but outside the case),
on opposite sides, so that their attractions might con¬
cur to swing the suspended lever out of the position
of repose which it had previously taken up, under
the action of the slight twisting force of the silver
wire. A new position of rest was thus established,
the small balls being pulled as much one way by the
attraction of the spheres as they were urged in the
opposite direction by the torsion of the wire. The
position of repose being observed from a distance by
a telescope (to avoid disturbance from the heat of
the observer’s body), the great spheres were then
changed in position so as to act upon the opposite
sides of the small balls, from what they formerly did.
The deflection and new stable position would be as
much on the other side of the zero, and the arc de¬
scribed would be an accurate measure of the double
deflection. The force of torsion for 1° of deflection
is known by the time of oscillation of the lever
and balls when free, and as the forces are exactly as
the angles, the force corresponding to any displace¬
ment becomes known. Cavendish conducted the ex¬
periment with his usual patience, judgment, and suc¬
cess ; he found the joint attraction of the small balls
and large spheres to be about of a grain, their
centres being 8-85 inches apart, and he thence com-
Result. puted the density of the Earth to be 5’48 times that
of water. Cavendish’s paper is as usual a model of
precision, lucidity, and conciseness. The attraction
of the fixed parts of the apparatus is calculated and
allowed for.
(158.) It would be difficult to mention in the whole range
y re* of physics a more beautiful and more important ex¬
periment. It has been repeated since by Reich of
Freiberg and Baily of London. The former obtained
5'44, the latter 5-66 for the Earth’s specific gravity;
this last result being worthy of much confidence from
the extraordinary care taken to avoid errors and to
obtain independent values of the quantities sought.1
Maskelyne continued his zeal for the promotion of
astronomy to the last. He superintended the publi¬
cation of 45 annual volumes of the Nautical Alma¬
nac. He left the whole of the observatory work in
perfect order, and the greater part printed. He had
the well-earned satisfaction of finding his observa¬
tions in request in every civilized country, the bases
of the most useful tables, and the tests of the most
advanced theories. He cultivated the friendly cor¬
respondence of astronomers in every country. Not
given to change, he preserved the instruments and
chief methods of the immortal Bradley ; but suffi¬
ciently alive to the necessity of progress in the
sciences, he introduced many simple but practical im¬
provements in the art of observation. Even in his
last years, satisfied that the celebrated quadrant of
Bird was no longer the best instrument for its pur¬
pose, and was besides sensibly deteriorated by use,
he adopted the circle instead (then recently come into
notice, though first used more than a century before
by Rbmer), and directed the construction of that by
Troughton, though it was not placed at Greenwich
until after his death, which occurred in 1811, in the
79 th year of his age. His biographer Delambre
mentions, that a considerable number of his posthu¬
mous memoirs were put into the hands of Professor
Yince for publication. They have not, however, ap¬
peared.
Practical astronomy was on the Continent far be¬
hind its state in England at the period of which we
speak. The various national observatories contri¬
buted comparatively little to the progress of science;
but there were of course exceptions, a few of which
we will here briefly notice.
The discovery of the four small planets2 Ceres,
Pallas, Juno, and Vesta, the first by Piazzi, the second
and fourth by Olbers, the third by Harding, gave cele¬
brity to those astronomers, of whom Piazzi and Olbers
were farther distinguished by many important labours.
To the latter we owe the discovery of several comets,
and one of the best methods of calculating their or¬
bits from observation. He was a person of much
simplicity of manner, made his observations with the
most unpretending means in the attic of his house,
and died at a great age generally respected. His
firmest friend was Baron von Zach, who had no slight
share in the discovery of the new planets, owing to
his having instigated the association of twenty-four
astronomers, chiefly in Germany, for the express pur-
1 The experiments of Cavendish are related in the “ Philosophical Transactions” for 1798 ; those of Reich in a separate small
work, entitled “Versuche uber die mittlere Dichtigkeit der Erde,” Freiberg, 1838 ; those of Baily in the “Memoirs of the
Astronomical Society,” voL xiv. A still more recent series of experiments by Reich gives 5'58, a close approximation to Baily’s
result.—(Phil. Mag. March 1853.) From observations with a pendulum in Barton coal-pit in 1854, Mr Airy has obtained a
density higher than any of the above.
2 In the Fifth Dissertation, page 789, Harding instead of Olbers is named as the discoverer of Vesta.
(159.)
Maske-
lyne’s im¬
provements
at Green¬
wich.
(160.)
Its superi¬
ority to
Continent¬
al observa¬
tories at
that time.
(161.)
Astronomy
on the Con¬
tinent.
Olbers—
Piazzi.
(163.)
French ai
of the me¬
ridian.
(164.)
Delambre
his charac¬
ter and
talents.
836
ASTRONOMY.—MASKELYNE—DELAMBRE.
[Diss. YI.
pose of ascertaining whether no planetary hody filled
the void between Mars and Jupiter, lo Piazzi, of
Palermo, we owe a most excellent catalogue of fixed
stars from observations with a moveable circle of
four feet radius by Ramsden. Oriani of Milan was
likewise one of the best informed practical astrono¬
mers of his time.
In France, after the death of the celebrated La-
caille, perhaps Lalande (who was exactly Maskelyne’s
contemporary) was the most active astronomer. To
him and his nephew we owe a very valuable catalogue
of 50,000 stars, lately edited by the British Associa¬
tion. But practical astronomy was seriously neglect¬
ed in France generally. The national observatory
was feebly superintended by the later members of
the Cassini family; of the French expedition under
Maupertuis to measure the length of a degree in Lap-
land, the Abbe Outhier alone, it is said, knew how
to use a quadrant, and the celebrated Lagrange was
as ill informed until instructed by Lalande.1
But the most important labours of the French
: astronomers at the close of the last, and at the com¬
mencement of the present century, were in carrying
out the measurement of the arc of the meridian from
Dunkirk to the Balearic Isles, with the more imme¬
diate object of fixing the length of the metre, but con¬
tributing to the solution of far more considerable pro¬
blems connected with the figure of the earth. We
connect this labour with the respectable name of De¬
lambre, who was more intimately associated with it
than perhaps any other person, though united with
such eminent men as Mechain, Biot, and Arago.
Delambre was the pupil of Lalande, who used to
; say that his disciple was his best work. He first ob¬
tained distinction as a computer of tables. Those of
the motions of the Sun, Jupiter, Saturn, and Uranus,
and of the satellites of Jupiter were deservedly
prized, and some of them are still the best of their
class. He was a man in whom the love of truth and
accuracy was conspicuous. Learned and patient, he
spared no pains in acquiring knowledge, and in using
it to the best purpose. As a calculator he was emi¬
nent. Physical astronomy he did not cultivate, ex¬
cept with a view to compare its deductions with facts.
He was intimately conversant with all properly as¬
tronomical methods and formulae. He knew the his¬
tory of every problem, and the details and modifica¬
tions of every astronomical instrument. He has
embodied the results of this vast industry in a series
of works (forming six quarto volumes) on the his¬
tory of his favourite science, which are without a
parallel for fulness and impartiality. He laboured
as conscientiously to ascribe the due credit to Hip¬
parchus and Ptolemy as to hold an equal scale be¬
tween the merits of French and British astronomers.
His critical knowledge of the ancient languages (for
he could speak Greek with fluency) was not more re¬
markable than his complete freedom from national
prejudices. Both attributes qualified him pre-emi¬
nently for the office of an historian. He published
also a large treatise on astronomy, and numerous
memoirs on practical subjects in the Connaissance
des Terns between 1788 and 1817.
Of his original labours the measurement of the ,(165-)
French Arc of the meridian, of which he has given afull
account in his Base du Systeme Metrique Decimal, is Arc.
the most important. As some account of this un¬
dertaking has been given in Sir John Leslie’s Dis¬
sertation, I shall state concisely a few particulars not
there mentioned. Not the least singular feature of
this gigantic work was the political crisis under
which it was conducted. So early as August 1790,
the French Constituent Assembly, on the motion of
Talleyrand, desired the king to write to the English
government, to represent the advantage of the two
nations uniting to adopt a common unit or standard
of weight and measure, which it was proposed should
be done by a joint committee of the Royal Society
and the French Academy.2 This application was
probably never made, at least nothing came of it;
but the Academy named their own committee, who,
after discussing three sorts of natural standards,—
the length of the pendulum in lat. 45° (first proposed
by Huygens in his Horologium Oscillatorium), the
length of a quadrant of the equator, and that
of a quadrant of the meridian from the equator to the
pole assumed to be elliptic,—adopted the latter,
and this labour was committed to Mechain for the
southern part, from Rodez to Barcelona (170,000
toises), and to Delambre for the northern, trom
Rodez to Dunkirk (380,000 toises). The southern
arc was afterwards extended to Formentera in the
Balearic Isles, and the whole length of the arc was
found astronomically to be 12° 22' 12"-6. Two bases
were measured (both by Delambre), one at Perpignan
of 6006 toises, the other at Melun of 6076 toises
(each about 7’3 miles). When the length of the for¬
mer was computed by triangulation from the latter,
the difference of the observed and inferred amount is
said to have been only ten or eleven inches.
But difficulties greater than physical obstacles pre- ^ ^
sented themselves to the completion of this vast work.
The excited state of the public mind during the most
frenzied period of the French Revolution rendered
the simplest operations matters of suspicion. The
nearer to Paris that the survey was carried on, the
greater were the precautions necessary. Instruments
were seized, assistants arrested, and night signals had
to be totally dispensed with. “ The coolness and in¬
trepidity of Delambre, added to unexampled patience,
(166.)
Its diflicul
1 Both anecdotes are told by Moll, who had them from Delambre.
2 The two governments and their respective learned societies had already co-operated in 1784 for a survey to connect
Paris and Greenwich Observatories.
Chap. III., § 1.]
ASTRONOMY.—MASKELYNE—DELAMBRE.
837
Mechain,
Biot, and
Arago.
(167.)
English
Arc.
were the principal means of extricating him from his
difficulties : hut his danger was often imminent, and
he appears to have sometimes heard the dreadful words
which, as an eloquent author has expressed it, were
the last sounds that vibrated in the ear of many an
unhappy victim.” The operations were actually sus¬
pended for a time hy a decree of Robespierre and his
colleagues, who deposed Delambre, along with Laplace,
Lavoisier, Borda, and others, from the Commission
of Weights and Measures, as being deficient in “ re¬
publican virtues and their hatred of kings.” They
were, however, resumed, and Delambre had finished
his share of the work long before his colleague Me¬
chain, whose shorter task was conducted amidst a
people rude and uneducated, indeed, yet far more to
be trusted than were then those of the north. Me¬
chain was apparently wayward and impracticable,
somewhat too aged for so great a work, yet a really
good astronomer. The want of agreement to within
3" of two sets of observations for latitude atBarcelona,
the southern end of the arc at that time, led him to
the suppression of one of them, and he was tormented
ever after by the consciousness of the evasion, which
deprived him of the tranquillity necessary to resume
and complete his work, which was done chiefly by
Delambre after vexatious delays.1 The error, which
may be said to have cost Mechain his life, was pro¬
bably owing to the instrument employed on this sur¬
vey, the repeating circle of Borda, only fourteen
inches diameter, with a rather weak telescope. The
opinion generally entertained in Britain is, that the
repeating circle was quite inadequate to the prodi¬
gious accuracy required of it, especially in the deter¬
mination of latitudes. The errors of mere division
are often trivial compared to those inherent in other
parts of an instrument. Of these a deficiency of op¬
tical power, and the want of absolute security of the
clamps, upon which the entire success of the princi¬
ple of repetition depends, are amongst the most ob¬
vious. The arc was finally prolonged from Barcelona
to Formentera by Biot and Arago in 1806. The
conclusion of the survey was not destitute of the ad¬
venturous character of its commencement. The
French astronomers ran many risks, underwent much
suffering, and Arago narrowly escaped finishing his
days in the dungeons of Spain.
The English survey carried on by Roy and Mudge
has been also noticed in the previous Dissertation,
The arc from Dunnose to Burleigh Moor amounts
to 3° 57' 13"T, the measured length to 1442953
feet. An arc of parallel was also measured from
Dover to Falmouth. We shall say something of its
later progress in the concluding part of this essay,
hut we have still to regret the postponed publication
of the British Arc of the Meridian, which we have
no reason to doubt will bear a favourable compari¬
son with the work of Delambre. The practical
appliances, the three-feet theodolite of Ramsden for
horizontal angles, and the eight-feet zenith sector
of the same artist for latitudes, were unequalled in¬
struments, and contrasted in almost every respect
with the light and portable apparatus of the French.
By means of the former the spherical excess of terres¬
trial triangles was first observed as a fact. The
results of the French and British arcs taken sepa¬
rately concuri’ed in showing a local curvature in this
part of the world altogether anomalous, the de¬
grees rather shortening in the northern part of each
arc. This fact, which must be imputed either to
lai’ge local attractions, giving errors of several seconds
in the determination of latitudes, or (less probably)
to a local departure in our quarter of the world from
the general or mean figure of the earth, sufficiently
shows the futility of the proposed method of deter¬
mining a natural, recoverable standard of length.
When combined with the measures of Bouguer in
South America and Lambton in India, and the revised
arc (measured in the beginning of this century) of
Svanberg and Melanderhjelm in Lapland, the French
and English measures give a general ellipticity some¬
what under 3^, which is probably as near the truth
as local inequalities admit of the determination being
made.
To Delambre was confided the drawing up of the
trigonometric formulae used in the calculations of the
survey, which were published in a separate work ;
De Prony conducting the laborious calculation of an
altogether new set of logarithmic tables, with the
aid of an immense staff of computers, the results of
whose labour (still in MS.) are preserved at Paris in
17 folio volumes. Delambre carried his personal
exertions so far as to compute his own triangles—•
which were also independently calculated by Le¬
gendre, Van Swinden, and Tralles.
As an acknowledgment of his merit, the highest
indeed in their power to bestow, the Institute of
France decreed to him in 1810 one of the Decennial
Prizes instituted by Napoleon. But the Emperor,
though professing to be the warm encourager of
science, suffered some meaner motive to interfere,
and refused to ratify the decision. “ Ce fut,” writes
Dupin, “ un pas dans la route qui le menait a sa
chute.” After the siege of Paris in 1814 Delambre
wrote a characteristic letter to his friend Moll. The
tranquil spirit which had braved the horrors of the Re¬
volution was not to be moved by the sounds of the
artillery of the allied armies. In spite of the can¬
nonade which he heard from his library, he laboured
from eight in the morning until midnight; and, con¬
scious of rectitude, he feared little the revolution of
circumstances, which changing dynasties might call
forth. “ Labour,” he says, “ occupies all my time
and all my faculties.”
As Secretary to the Academy of Sciences for the
(168.)
French
trigono¬
metric for¬
mulae and
tables.
(169.)
Prize
awarded to
Delambre.
(170.)
1 The history is minutely given by Delambre himself in his Biography of Mechain.—Astron. du XVIII. Siecle.
838
ASTRONOMY.-—SIR WILLIAM HERSCHEL.
[Diss. YI.
His impar¬
tiality—
his death.
(172.)
Sir Wm.
Herschel;
(173.)
his exten¬
sive works
(174.)
early his¬
tory.
Mathematical Sciences, he had to make frequent re¬
ports on the progress of those progressive branches
of knowledge, and to contribute memoirs of the most
eminent academicians, both native and foreign. Both
these duties he executed with his customary labour
and fidelity. His private character was as amiable
as his public career was distinguished. The tendency
of his writings was constantly to enforce the histori¬
cal credibility of the Scriptures, especially with regard
to the most ancient astronomical records. The value
of his testimony is increased by his unusual skill in
philology. He died 19th August 1822, aged 73.
We reserve some farther remarks on the geodetic
results of this period, and especially on the pendujum
observations with which they were accompanied, for
the fourth section of this chapter.
2. Sir William Herschel.—History of Sidereal and Telescopic Astronomy to 1820. Her¬
schel as an Optician.—Planet Uranus—Solar Spots—Orbits of Double Stars JVebulce Ihe
Milky Way—Sun's Motion in Space.
The eighteenth century was not, generally speak¬
ing, distinguished by original observations. The ex¬
ceptions stand out with all the brighter lustre.
Amongst these, the discoveries of Sir William Her¬
schel occupy perhaps the foremost place. Arago has
affirmed that Slough is the spot on the earth’s sur¬
face signalized by the most numerous discoveries,
and in a certain sense this is strictly true. No one,
before or since (with possibly the exception of Mr
Hind) has added so many new bodies to the known
planetary system, and this at a time when such
discoveries were rarer, more unexpected, and more
difficult than now. His researches on the fixed
stars are not of a nature to have their importance
numerically estimated.
Sir William Herschel’s career was one of the
_ longest and of the most sustained labour in the history
’ of science. To have contributed papers—often several
in one year—to the Philosophical Transactions for
thirty-nine consecutive years, from 1780 to 1818,
with but two exceptions, is a feat of astonishing per¬
severance ; but if we recollect that many of these
papers contain announcements of capital discoveries,
that every one of them is stored with original matter,
and that the author had already passed his fortieth
year when he commenced the production of this as¬
tronomical library, we cannot withhold a tribute of
the warmest admiration.
England cannot claim Herschel as her own, except
by adoption. He was born at Hanover in 1738, and
was one of a numerous family who supported them¬
selves chiefly by their musical talents. William
Herschel, the third son, came to England in 1759
with his elder brother, and after struggling with many
difficulties, found himself in comparatively comfort¬
able circumstances as an organist at Bath. In 1774
he had executed a reflecting telescope with his own
hands, and soon acquired so much dexterity as to
construct instruments of ten and twenty feet in focal
length. In 1780 he contributed his first paper on
the variable star in Cetus to the Royal Society, and
the following year (13th March 1781) discovered the
erratic body, which he at first took for a comet, but
which proved to be a planet exterior to Saturn; the
first addition therefore to the number of the primary
planets since a period of an immemorial antiquity.
So fortunate a success made the name of Herschel
speedily famous, and he was effectively befriended by
George III., who brought him to live near Windsor,
and gave him a pension.1
From this brief sketch it will appear how great
were the obstacles which Herschel had to vanquish
before he became a man of science, and that, besides
the claims to distinction already enumerated, his
knowledge and his skill were acquired in spite of
every disadvantage.
Practical Astronomy naturally divides itself into
two great branches, that which depends upon the
use of the telescope merely; on the telescope and
micrometer ; and that which determines the absolute
places of the heavenly bodies, and requires the aids
of divided instruments and a well furnished obser¬
vatory. In the century to which he belonged Her¬
schel is the type of the telescopic observer, Bradley
of the instrumental. The discoveries of Aberra¬
tion and of Nutation by the latter may stand a com¬
parison with any in the history of science, but the
resolution of Nebulae and the proof of the mutual
connection of stars in binary systems are not less
distinguished and original. Herschel would have
gained a great reputation as an optician, merely by
the wonderful improvement which he effected in the
dimensions and magnifying power of telescopes, and
by the skill with which he applied them to celestial
observations. He would have stood still higher as
an astronomer had he been merely the first observer
of a new planet and of eight secondary ones, as well
as of several comets, and the author of many nice
1 It may be doubted whether any other similar annuity was given at that period on scientific grounds alone, and it is difficult
to estimate the amount of benefit thus conferred on astronomy, for nothing short of the entire devotion of a lifetime could have
produced such results as we owe to Herschel. His proposal to name his planet after the Sovereign was a very natural expression
of his gratitude at a period when no rule whatever existed on the subject. See an interesting letter from Herschel to Sir
Joseph Banks (who was also a warm friend) in Weld’s History of the Royal Society, ii. 146, note. Herschel was elected into the
Royal Society 6th Dec. 1781.
(171.)
(175.)
(176.)
Division of
Practical
Astronomy
into Tele¬
scopic and
Instru¬
mental.
Chap. III., § 2.]
ASTRONOMY.—SIR WILLIAM HERSCHEL.
839
(177.)
(178.)
Herschel as
?n optician.
(179.)
Magnify-
'ng and il¬
luminating
power of
telescopes.
observations on the physical appearance and con¬
stitution of the sun and planets ; but his great glory
was in sidereal astronomy, of which he laid almost
the foundations, by means of discoveries which he
fortunately lived long enough to see confirmed and
enlarged beyond his reasonable hopes.
In this brief sketch of Herschel’s achievements
(which in his own department may be said to embrace
those of his age, for he had hardly an imitator, and cer¬
tainly no rival) we shall, in the first place, condense
into small compass what is to be said on the two
former heads—his merit as an optician and as a
planetary observer.
To construct good telescopes is itself no easy art,
especially if they are to be carried to a size and per¬
fection previoiisly unattained. To ascertain the best
composition, whether of glass or metal, to melt and
to cast it in the right way, is one branch of the art
which may be called generally the chemical part. To
fashion the lens or mirror correctly by grinding, and
to fit it for optical use by giving it an exquisite polish,
is a second step requiring a peculiar mechanical skill
and perseverance. To mount the telescope effec¬
tively is another and entirely different problem in
mechanics; and all these the amateur astronomer
must be prepared to accomplish with his own hands,
unless he command the services of practical opticians
to an extent rarely to be bought. Amateurs have
indeed seldom succeeded except with reflecting in¬
struments, and Herschel acted very wisely in devot¬
ing himself to their improvement at a time when the
success of Dollond with achromatic telescopes had
rendered the Newtonian form unfashionable. The
real secret of Herschel’s success was his astonishing
perseverance; his determination was to obtain tele¬
scopes of twenty feet focal length or more, and of a
perfection equal or superior to that of the small ones
then in use. He himself relates, that whilst at Bath
he had constructed 200 specula of seven feet focus,
150 of ten feet, and about 80 of twenty feet; a proof
of extraordinary resolution in a man of limited means
and engaged in a laborious profession. By making
so great a number he could select those having
the most perfect figure, especially before he had con¬
trived a method of obtaining mechanically a para¬
bolic form, almost with certainty. This method was
not divulged. He was justified in keeping his secret,
whilst he made a handsome income from the manu¬
facture of telescopes for sale. Lord Rosse and Mr
Lassell have had the merit of publishing their
methods, which by their results would appear to be
at least equal to Herschel’s.
The usefulness of telescopes depends on two dis¬
tinct qualities—magnifying power and illuminating
power. The former may be gained indefinitely by
diminishing the focal distance of the eye-glass ; the
latter can be had only by increasing the diameter of
the object-glass or speculum, so as to collect the rays
which fall upon a circle of large diameter from every
point of the object examined. But in order that
the whole light may be effective, the magnifying
power of the eye-glass must be sufficient to condense
the emergent pencil within the diameter of the pupil
of the eye. The proportion in which these two
qualifications are requisite to obtain the best results
in astronomy is a matter involving nice questions
both of theory and practice. Sir William Herschel
did more than any one who preceded or fol¬
lowed him to solve them. On the whole, the illu¬
minating power is perhaps the most important, whilst
it is the most difficult of attainment; but in truth
each class of telescopic objects have their own rule
in this respect. Brilliant objects, such as Venus, and
moderately bright stars, do not require large aper¬
tures ; very feeble objects, as the remoter satellites
and the nebulse, require indispensably great illumina¬
tion. Five satellites of Saturn were seen by Sir W.
Herschel in his great telescope by the naked eye alone,
that is, without the advantage of the magnifying
power of a lens. On the other hand, Sir John Her¬
schel tells us that the satellites of Uranus cannot be
clearly made out without a magnifying power of at
least 300, whatever may be the aperture of the tele¬
scope.1
The mention of magnifying powers is calculated to (180.)
mislead rather than otherwise in comparing the effi- Magmfy-
cient means of different astronomers. The magnify- u°fdPi°wer
ing power used by Galileo did not exceed thirty-two Astronomy,
times the diameter. Huygens, who used aerial tele¬
scopes of immense length, pushed it to 163 times.
Auzout is said to have given a power of 500 to one
of these gigantic instruments of 300 feet in length ;
but it is easily understood that such achievements
were little more than nominal, the mechanical diffi¬
culty of managing these instruments being excessive.
Short professed to carry the magnifying powers of
his Gregorian reflectors to 1200, but still they yielded
only trifling fruits to astronomy. It required that
such instruments should be made and used fami¬
liarly, not as objects of luxury of which but one or two
were ever brought into actual use. Herschel applied
even to his seven-feet Newtonian (his favourite and
smallest working size, having 6-3 inches aperture)
powers exceeding 2000. To his largest instrument
(thirty-nine feet focus) was occasionally applied a
power of 6500. The highest powers usefully em¬
ployed with the gigantic achromatics of Pulkowa and
of Cambridge (in America), do not exceed 1822 and
2004 times respectively.
The motion of the earth and the troubled state of U8L)
Its limits.
1 Struve found that with a small telescope, magnifying three times, and having the same aperture with the pupil of the eye
(0-2 inch), he could count nearly twice as many stars (accurately 1-83 times) as with the naked eye. This result, interesting on
several accounts, deserves farther enquiry.—Etudes d1 Astron. Stellaire, p. 85.
840
ASTRONOMY.—SIR WILLIAM HERSCHEL.
[Digs. YI.
4
the atmosphere, especially in these climates, impose
a speedy limit to the increase of magnifying power,
unless in exceptional circumstances. The same ob¬
jections do not apply to the increased aperture
and illuminating power of telescopes. This con¬
sideration induced Herschel to construct his forty-
feet reflector, the funds being advanced by the king,
on the recommendation of the Royal Society. The
speculum had a useful surface precisely four feet in
diameter, the thickness three and a half inches, the
weight when cast above 2000 pounds. The second or
plane mirror having been dispensed with, the image
was thrown to one side of the object-end of the tube
bv means of a very slight inclination of the speculum,
and was there observed directly by a common eye-piece
or single lens, the observer being thus stationed with
his back to the object he is viewing. This vast in¬
strument collected a cone of rays from a distant point
between six and seven times larger than the twenty-
feet instrument commonly employed by Sir W. Her¬
schel, of which the aperture was 18-8 inches. This
telescope was not frequently used, partly from the
rarity of sufficiently steady weather, and from the
difficulty of preserving the figure of the mirror under
changes of temperature.1 Its figure was also affected
by flexure under its own enormous Aveight, and it
has been found one of the greatest difficulties by those
who have followed Herschel’s steps to avoid this
source of error. The forty-feet speculum has been
religiously preserved by the filial care of Sir John Her¬
schel, in whose possession the writer of these pages
had the pleasure of seeing it, now many years since,
in a state of high polish. It remains in a deposit
hermetically closed, at Slough.2
(182.) Herschel made an ingenious determination of what
negating- called the space-penetrating-power of telescopes, by
power of which he discriminated the relative distances at which
telescopes. a given fixed star would become invisible in his
several instruments. It was grounded on the as¬
sumption that the visibility of the object depends,
first, on the density of its light reaching the eye, and
secondly, on the number of rays of that density
concentrated in the image. The former quantity
varies inversely as the square of the given distance,
the latter directly as the square of the aperture of
the telescope; the limiting visible distance therefore
of the radiant body will be simply as the aperture.
To this he applied corrections depending on the loss
of light by reflection at the specula, and by trans¬
mission through one or more eye-glasses. On this
scale the space-penetrating-power of the seven-feet
Newtonian being twenty, that of the twenty-feet tele¬
scope (front view) was seventy-five, and the forty-feet
telescope 192. These estimations, as we shall see,
form an important step in Herschel’s generalizations.
(183.) Of new bodies belonging to our system he dis¬
covered Uranus and his six satellites, the two satel- Herschel's
lites of Saturn next to the ring, and several comets. ^8®?very
He did not, so far as we know, even suspect the (0r Oeor^i.
planetary character of Uranus, which he believed to nm Sidus)
be a comet. The honour of this appears to be due
partly to Saron of Paris, partly to Lexell of St
Petersburg. Arago supposes that Laplace had
also a share, but the evidence bn the whole matter
is somewhat obscure. Unquestionably it was an ex¬
ceedingly difficult matter to fix upon a correct orbit
for a body moving with such extreme slowness within
the limits of the first few weeks after its discovery,
and its distance was far beyond what any one calcu¬
lating a comet’s path would readily assume. The
original discovery was also a fortunate one, for but
eleven days previously the planet was in a position
apparently stationary. It has led to results of still
higher interest by the prediction of the existence and
place of Neptune from the irregularities of Uranus.
The satellites move almost perpendicularly to the
ecliptic. Strange to say, they remained for, I be¬
lieve, more than half a century, unseen by any eye but
that of their discoverer and his son: and two of them
still stand recorded on the single authority of Sir W.
Herschel. They are the least specks of light which
optical power has ever made visible. (i§4.)
Herschel made many observations on the physical observa-
appearance of the sun, moon, and nearer planets, and tlonsonjhe
the times of their rotation. Into these details we ^ ’
cannot now minutely enter. The papers which record
them are characterized (like all those of the same
author) by the faithful minuteness with which the ob¬
servations are detailed, and by the mention of every in¬
fluential circumstance by which the results might be
affected. In the case of observations so exceedingly
delicate as those of the planets, the astronomer has to
keep up an incessant struggle between the anxiety to
record all that he sees, and that of recording nothing
more than he really and perfectly sees. One or two
glimpses are not sufficient. Herschel at one time
imagined that the new planet had one or more rings
which unquestionably do not exist. His elaborate in¬
vestigation of the figure, belts, and rings of Saturn, the
incredible tenuity of the 1 after, and the fact of their ro¬
tation in 10h 32m, were amongst the most interesting
of his observations, and were illustrated by drawings
made with remarkable care. The edge of the ring was
seen in 1789, when it had totally disappeared in all
but his forty-feet telescope, and he estimated that its
thickness could not exceed 100 miles. How astonish¬
ing the magnitude and thinness of this stupendous
circular plane, or rather series of flat rings ! Some
idea of it may be deduced from the fact that if the
thickness of the paper on which this is printed be
taken to represent that of the rings, their greatest
diameter would correspond to nine inches. Observa-
1 The first object viewed by Sir W. Ilerschel with his great telescope in 1789 was the nebula in Orion ; possibly it was also
the last, for he again observed it in 1811 (See Phil. Tr. 1811, p. 322).
2 See Weld’s History of the Royal Society, ii., 193.
Chap. III., § 2.] ASTRONOMY.—SIR WILLIAM HERSCHEL. 841
tions on the other planets and on the moon we here III. Of the Grouping of the Stars generally in
pass over for want of space. space, and the significance of the Milky Way
(185) I have reserved the observations on the nature of IV. Of the Motion of our System in space
ontneMm. the gun tQ thls placej because everything leads us to I. On Double Stars. Discovery of Binary Sys-
assimilate the nature of the sun and of the fixed stars, terns.—Double stars were noticed as objects of curio-
The belief that the luminous disk of the sun is a photo- sity even before the discovery of the telescope The
sphere or luminous atmosphere of great tenuity sur- group of the Pleiades attracted attention from the
rounding a globe of comparative density and dark- earliest times. Amongst the earliest double stars
ness, was long anterior to Herschel, and in fact due carefully observed were g Ursa? Maioris (by Kirch
to Dr Patrick WTilson of Glasgow, whose admirable 1700) ; « Centauri in 1709 ; y Virginis and Castor
paper on this subject was published in the Philoso- by Bradley (1718 and 1719) ; Mayer made a con-
phical Transactions for 1774, in which he explains siderable catalogue of double stars in 1756. But
the phenomena of the solar spots by apertures in the Lambert first announced in 1761 (in his Lettres Cos-
lummous atmosphere, discovering the dark nucleus mologiques) the probability of the mutual revolution
below, and some shell or shells of intermediate of suns, in these remarkable words (speaking of clus-
bnghtness which form the penumbra. 1 These con- ters of stars), “ It will perhaps be decided whether
elusions were most clearly and ably deduced from a there are not fixed stars which make their revolutions
careful observation ofthechangingaspect of the spots, in no long periods round their common centres of
as they move by the solar rotation from the centre gravity.” Mitchell, in 1767 and 1784, maintained
followed th<5 °f lllS ^ 18 t0 136 reSretted tiiat tlie same views> supported them by an applica-
Patrick Herschel does not more pointedly refer to the dis- tion of the then young science of probability, hazard-
Wilson. coveries of Wilson, which were more than twenty ous in its principle, and unquestionably wrong in its
years antecedent to his first paper on the subject, numerical solution.^
and with which he could hardly fail to have been ac- Sir W. Herschel commenced his observations on
quamted. A similar icmark applies, in a less degree, double stars with the hope of ascertaining the Annual
to his papers generally, which rarely contain references Parallax in the manner previously indicated by
to the observations and speculations of his predeces- Galileo and James Gregory; but, as in many parallel
sors. Herschel adopted Wilson’s hypothesis almost instances, whilst he failed of his main result, he dis-
literall), and his long series of patient observations on covered unsought a phenomenon more unexpected
the sun, made with high powers and at an eminent risk and probably more interesting. With the micro-
to his eyesight, enabled him to classify the singularly metrical means at his disposal," he entirely failed in
varied appearances of that wonderful orb, and to detecting any semi-annual fluctuation of the inter¬
draw some probable conclusions from the excessive val between the members of the pair of stars, but
rapidity and seeming tumult of the exterior portions he found (in some instances) progressive and con-
of it. That the photosphere is strictly gaseous he tinually increasing changes both in the relative
rendered very probable, an inference confirmed by position and distance of the two. He com-
the direct observations of Arago as to the un- menced his observations in 1779, but it was not
polarized character of its light. The singular dis- until 1802 that he thought himself entitled to an-
closure of faint red prominences extending far beyond nounce with confidence his discovery of the circula-
the disk, and observed in the total eclipses of 1842 tion of one sun .round another, or rather of both
and 1851, shows that there is still much which i'e- round their common centre of gravity. Herschel’s
gards the mysterious nature of the sun within reach first list of orbital stars {Phil. Trans. 1803, where
of direct observation ; and the same may be observed this splendid discovery was first published1 2 3) includes
of the direct experiments lately made on the heat the chief examples now known ; and they have all
and light of different parts of the disk, which diminish been confirmed. That of which the revolution is
to one-half between the centre and the edge, and most rapid is £ Herculis, which has a period of 31J-
appear to attain a maximum at the solar equator. years, and consequently has revolved twice round
^(186.), A convenient, though not a strictly chronological since it was first observed, whilst the slow planet
sidereal18 a.rrangemenfc °f Sir Wr. Herschel’s more important Uranus has not yet returned to the position of its
discoveries. sMereal discoveries and speculations may be made first discovery. Herschel does not appear to have
under the following heads :— received a medal or other public recognition of this
I. Of double Stars and their mutual connection. signal success.
II. Of the Nature of Nebulae, and the so-called Of the subsequent progress of this interesting in-
Nebular Hypothesis. quiry we shall speak in the latter part of this chapter.
1 Flamsteed appears to have entertained in 1681 a somewhat similar opinion, as we find from a letter published (1855) in
Sir David Brewster’s Life of Newton, vol. ii., p. 103.
2 See art. (85) and note.
3 It was in fact distinctly though incidentally announced in his paper of 1802, though the proofs were given the following
year. See Phil. Trans. 1802.
VOL. I. 5 o
(187.)
Double
stars—or¬
bital mo¬
tion;
(188.)
failed to
discover
parallax.
(189.)
842
ASTRONOMY.—SIR
WILLIAM HERSCHEL.
[Diss. YI.
(190.)
Nebulae.
(191.)
Classifica¬
tion of ne¬
bulae ;
(192.)
resolvable
and unre-
solvable.
Greater precision has been in some respects attained, but
little, if anything, added to the theory of double stars.
II. On Nebula and the (so-called) Nebular Hy¬
pothesis.—Vhe cloudy patches of mild light which
are visible in clear but moonless nights m various
parts of the sky are called nebulae from their resem¬
blance to light vapours moderately illuminated.
Some regions of the sky abound more with them than
others. The Milky Way presents to the naked eye
a nebulous appearance extending over large tracts,
and nebulae more or less dense are frequent within and
near its borders. These facts were well known from
an early period. Some conspicuous nebulae were
described in the sixteenth century; that in Andro¬
meda by Marius and the conspicuous nebula in
Orion by Huygens. Halley added several, but the
first descriptive catalogue of these objects was pub¬
lished by Messier in 1783 (in the Connaissance des
Terns), and it forms the basis of the modern obser¬
vations.
Sir W. Herschel took up the subject with his cus¬
tomary zeal. In 1786 he published a catalogue of
1000 nebulae, which he had increased by 1802 to
2500. The first step to some appreciation of the
nature of these extraordinary appearances was of
course to classify them, and this Herschel did with
such success that it may be affirmed that his classes
remain the best at the present time, as generally re¬
presenting the phenomena. Without entering into
all his details, the following division embraces the
main facts :—
A. Clusters of stars.
B. Nebuhe proper.
a. Having a certain regularity, as 1. Circular or
planetary nebulae ; 2. elliptic; 3. annular.
jS. Wholly irregular, as the nebula of Orion,
the Magellanic clouds, &c.
C. Nebulous stars.
Remarks. A number of faint stars produces a
nebulous haze. This is a physiological fact. Parts
of the Milky Way which present this appearance to
the naked eye are at once shown by a telescope of
small power to be composed of stars.1- Patches which
appear nebulous in such a telescope are shown by a
better one to be composed of small stars. This is
called the Resolution of a nebula. Such resolutions
become more and more numerous as the apertures of
telescopes are enlarged. Lord Rosse’s telescope has
resolved several which withstood the highest power
of Herschel’s. One inference might therefore be that
all nebulae are clustered stars, at a greater or less
distance. Such an opinion is very general, and very
plausible. It may on the other hand be observed
that Herschel abandoned this his earlier inference,
whilst, at the same time, he proceeded diligently with
the resolution of successive nebulae, by means of his
powerful telescopes. He maintained on the contrary to
the last that nebulae belong to two classes, resolvable
and irresolvable. The latter he believed to be composed
of diffuse self-luminous matter, more or less con¬
densed, whilst the milky light of the former is occa¬
sioned by the blended gleam of numerous close stars.
With this difference, we find his views regarding the
changes in the sidereal system and the progress of
the condensation and breaking up of nebulae, nearly
the same in his earlier and later papers, particularly
those of 1785 and 1811.
The opinions of Herschel on these changes were (193.)
the following Having observed that the more
regular nebulae (whether with a central star or their pro-
not) presented almost invariably an appearance of gressive
gradually increasing brilliancy towards its centre, ™nn(lensa'
he was led to conclude that this is due to the aggre- 1 ’
gation of the self-luminous parts in virtue of their
mutual gravitation; and the conclusion would so
far be the same, whether the parts thus coalescing
were in fact numerous distinct masses, or were like
a vapour diffused through space. This was the pro¬
cess of condensation, which he inferred on the one
hand from the law of gravity, on the other from the
generally symmetrical arrangement of the luminous
matter in nebulae of the first class. In order to de¬
tect, by actual observation, the progress of condensa¬
tion, he invented a simple and highly expressive
terminology, indicating the general brightness, the
amount of its gradation, and the lavj of its gradation
from the circumference towards the centre. In
whatever degree Lord Rosse’s late observations may
be considered to deprive nebulae of the character of
symmetry which Herschel had conferred on them,
the general fact of an apparent condensation in a
great majority of instances cannot be denied.
The breaking up of nebulae (also described in his (^^
paper of 1785, as well as in his later ones) is likewise in
an inferred change anticipated in large irregular some cases,
nebulae, which usually exhibit bright spots or centres,
with irregular vacant spaces, which sometimes seem
like portions of a black and distant profundity seen
through the rents of a nebulous veil. Herschel sup¬
poses that the luminous centres are also places of
greatest attraction, and must gradually draw away
the star-like substance from the rarer spaces.
It is curious that these speculations of Herschel (195.)
(which are substantially common to his papers of
1785 and 1811) had been at least imagined at a very ^ hyp0.
early period. Arago has pointed out that Tycho thesis,
and Kepler conceived the New Stars of 1572 and
1604 to have resulted from a sudden condensation
1 The group of the Pleiades presents a peculiar instance. When the eye is turned full upon it, no more than six stars (as is
well known) can be counted, but when the eye is turned aside through 10° or 15°, by a peculiarity of indirect vision by means of
the lateral parts of the retina, the group appears a mass of nebulous light. This arises from an immense crowd of stars just
below visibility, which, probably from the greater sensitiveness of this part of the eye, make a sensible though somewhat indis¬
tinct impression. This observation as to the Pleiades, and the inference which explains by it the seeming countlessness of the
stars when viewed cursorily, were published by the present writer in Brewster’s Journal for 1826.
Chap. III., § 2.]
ASTRONOMY.—SIR WILLIAM HERSCHEL.
843
(196.)
Herschel’s
opinions
on the dis¬
tance of
nebulae;
(197.)
and their
changes of
form.
(198.)
Theory of
condensa¬
tion.
of diffuse celestial matter, such as the Milky Way ex¬
hibits, and Tycho alleged that the new star was sur¬
rounded by an obscure space, half as large as the
moon’s disk. The history of Science scarcely pre¬
sents a more curious anticipation.
One practical difference between the earlier and
later views of Herschel on the nature of nebulae, was
as to their distance from our system. For if the milky
aspect be due to a confusion of small stars, it is
assumed that they must be almost incredibly distant.
In his memoir of 1785, he estimates this distance at
not less than 6000 or 8000 times that of Sirius.
If, on the other hand, the nebulous appearance be
due to a diffusion of starry matter, the distance may
be that of any order of fixed stars ; and this opinion
derives weight from the evident connection of some
nebulse with stars round which they seem to cluster
or hang almost like a drapery. Thus in 1811 he
supposed that the nebula in Orion need not be more
distant than a star of the 7th or 8th magnitude.
It appears from his paper of 1802 (page 500),
that his ideas about nebulae were then wavering. Be¬
tween that time and 1811 he elaborated the nebular
hypothesis, so far as it is due to him. He seems to
suppose that starry matter was once in a state of in¬
definite diffusion. That during “ an eternity of past
duration” (Ph. Tr., 1811, p. 287) it has been “break¬
ing up” by condensation toward centres more or less
remote. That the Milky Way—or at least the nebu¬
lous parts which it contained—and the dispersed ne¬
bulae, are the relics of this former state of things.
That where condensation has gone on more energeti¬
cally, we have nebulse with a gradually or rapidly
increasing brightness towards the centre;—if still
more energetic, a nucleus, or it may be a planetary
nebula;—next a nebulous star, which he supposes
our sun to be, and the zodiacal light a relic of its
nebula (p. 311);—finally, the completely formed
stars may be assumed to be merely consolidated ne¬
bulse. (See pp. 284, 285, 299, 310.) This conden¬
sation, he believes, must be accompanied by rotation
due to the originally irregular distribution of the
gravitating particles (p. 312-319).
The 'proofs on which the whole of this cosmogony
rests are, l.s£, the gradation of appearances above
described, to be collected from distinct objects in the
heavens; and, Zdly, supposed changes observed by
him in the nebula of Orion and others, during thirty
years, and even during intervals of a few years. As to
the last argument, it is admitted, we believe, by the
best authorities, to be without weight. The changes
of aspect of such curiously faint and graduated ob¬
jects, even to the same eye using the same telescope,
are numberless, and may be due to the slightest at¬
mospheric and physiological influences. This test
(as applied hitherto) is therefore generally rejected.
Against the first proof much might also be urged, for
1 The most intelligible account of the nebular hypothesis, in
Outlines of Astronomy, Articles 870 to 872.
which we cannot afford space. Its idea is essentially
derived from the Natural History sciences, and I can¬
not help thinking that Herschel must have derived it
from some one more conversant with these than with
mechanical physics. This opinion is confirmed by a
curious illustration which he uses in the same paper
of 1811. “ There is perhaps not so much difference
between them” (viz., the whole group of nebular and
quasi-nebular phenomena), “ if I may use the com¬
parison, as there would be in an annual description
of the human figure, were it given from the birth of
a child until he became a man in his prime” (p. 271).
A theory or hypothesis in some respects similar (199.)
had been previously expounded by Laplace in the Laplace’s
concluding chapter of his Systeme du Monde. At
least it so far resembles it, that he puts forth Tycho’s connected
notion of the star of 1572 being a condensation of a with Her-
widely-spread stellar atmosphere (without, however, scbel’s.
naming Tycho), and supposes that our solar atmo¬
sphere might also once have extended to the limit of
the system, and that the planets were thrown off suc¬
cessively in the form of nebulous rings (subsequently
condensed into spheres) from the equatoreal parts of
this vast revolving mass during its contraction. He
ascribes to Saturn’s ring a like origin. It required all
the authority of a name like that of Laplace to circu¬
late a theory so bold, if not extravagant. He adhered,
however (at that time), to the old idea of the consti¬
tution of nebula?, which he considered to be composed
entirely of stars, and to be at once the most distant
and the most massive aggregations of matter in the
universe. Herschel could hardly fail of being ac¬
quainted in 1811 with Laplace’s views, and they pro¬
bably in some degree influenced his own, particularly
as to the cause of the rotation of his condensing suns.
But he prudently reserved his hypothesis for sidereal
objects, and did not deduce from it a planetary cos¬
mogony. In the later editions of the Systeme du
Monde, Laplace quotes Herschel’s observations in
confirmation of his views, adopts the notion of a dif¬
fuse nebulous matter, and considers that an hypothesis
arrived at by a “ remarkable coincidence” in oppo¬
site directions, is thereby invested with a great pro¬
bability.
Even Herschel’s more limited conclusions have (200.)
been very dubiously received, and notwithstanding Doubts re-
the weighty adhesion of Humboldt, and Arago toSardinSlt:-
them, it may be affirmed that natural philosophers
generally are content to leave the solution of this
cosmical problem to that distant posterity which
alone can hope to witness unequivocal evidence pro¬
gressive change in those wonderful objects.1
III. Of the Grouping of the Stars generally in (201.)
Space, and the Significance of the Milky Way.—The Tllf C0I)st1'
earlier astronomers, and particularly Halley, naa 8tarry hea_
the idea that the nebulas—which abound so remark- vens, and of
  —    the Milky
its least objectionable form, will be found in Sir John Herschel’s Wayinpar¬
ticular
Kant,
Lambert,
Wright.
(202.)
HerscheFs
“ gauges.”
(203.)
Plenitude
of stars in
different
regions of
the sky,
g44 MATHEMATICAL AND PHYSICAL SCIENCE. [Diss. VI.
ably in the Milky Way, and which may in some sense
be almost said to compose it—are the parent-matter
of stars, whilst stars abound in their neighbour¬
hood, or seem partly to compose them, in a state
of incredible aggregation. That the mass of sidereal
matter composing the Milky Way (which forms an
irregular girdle round the whole heavens1) has some
special reference in its locality to our solar system,
was also an early idea, which, towards the middle
of the 18th century, had attained to something like
a definite speculation in the minds of Kant, Lambert,
and other philosophers, chiefly those of Germany.
Its origin is perhaps traceable to Thomas Wright of
Durham2 (1742), who affirmed that the Milky Way
is a projection on the sphere of a stratum of stars, in
the midst of which our Sun and system are placed—
somewhat excentrically, however, towards Sirius.
I do not know whether Sir W. Herschel derived
his first ideas on the subject either from English or
German authors. His customary silence (which is
to be regretted) on the history of his discoveries,
leaves us in doubt of his originality. Be this as it
may, he proceeded to test the reasonableness of the
speculation, in that definite and thorough manner
which was very characteristic of his genius. He pro¬
ceeded to number the stars after a fashion which, if
the early attempt of Hipparchus was pronounced in
its day impious, might well have been accounted,
even in Herschel’s age, impossible. To use his own
bold expression, he gauged the heavens, by counting
the whole number of stars visible in the field of his
20-feet reflector as many times as possible, and in
every region of the sky which was visible from
Slough, distinguishing the results of each region. As
it was impossible in one lifetime to accomplish the en¬
tire survey (for the complete sphere contains 883,000
fields of 15' each in diameter), he took an average for
each region, and thus determined the general popula¬
tion of the sky in all directions. The result more than
confirmed the suspicions of Wright and Lambert,
and demonstrated a remarkable, and, on the whole,
a steady law of decrease, from the central zone of the
Milky Way in opposite directions, until we reach two
poles, one in the Southern, the other in the Northern
hemisphere, which are the localities poorest in stars.
This discovery (for it well deserves the name),
which assigns a Law to the distribution of the entire
visible bodies of the Universe in space, is surely one
of the greatest which man has ever attained. The
simplicity of the means by which it was reached, and
the amount of mere mechanical and arithmetical la¬
bour which forms its sole basis, and constitutes its
essence, is a powerful lesson of how little mankind
has a right to scorn the humblest means of knowledge,
or to attach the prerogative of genius only to the
lofty flights of imagination and speculative philoso¬
phy.3 This triumph belongs to Herschel alone; his
successors have commented upon and scrutinized his
results ; his son has “ gauged” the Southern Hemi¬
sphere, with like results; but the original result is
substantially confirmed. We may therefore antici¬
pate so far as to quote the numbers denoting the
“ plenitude” of stars as we recede from the equator
of the Milky Way in either direction, first, as calcu- as observed
lated by Struve4 and Sir John Herschel, from Sir Wil- by Sir Wil¬
liam Herschel’s observations in the Northern hemi-
sphere; secondly, as calculated for the Southern he- Herschel.
misphere by Sir J. Herschel, from his own observa¬
tions at the Cape of Good Hope.
Limits of Zone,
reckoning from
Equator of
Milky Way.
0°- 15°
15 - 30
30 - 45
45 - 60
60 - 75
75 - 90
Average Number of Stars visible in 20-feet
Reflector; Aperture 18-8 inches ; Field
15' diameter.
X. Hemisphere
(Magn. Power 157.)
53-4
24-1
136
8-2
5-4
4-3
S. Hemisphere
(Magn. Power 180.)
59-1
263
13-5
91
6-6
6-0
This table shows the extreme condensation of the stars
round the “ Galactic” equator; indeed Struve carries
the average “ plenitude” of the field as high as 122
stars in that plane itself.
According to Herschel’s views, the whole visible fir¬
mament of stars belongs to the nebula of the Milky
Way, of which our own system forms an infinitesimal
part. In his paper of 1785, on “ the Constitution of
the Heavens,” he inferred that the general form and
comparative limits of this cluster of stars might be
found from his “ gauges,” by supposing that his tele¬
scope brought into view every star between the specta¬
tor and the surface of the cluster. Supposing the stars
to be itniformly distributed within the cluster, it is
easy to see that the number counted in a conical space,
having an angle of 15' at its vertex, would give the
height of the cone, or the depth to which the spectator
is immersed in the cluster, in that particular direction;
and thus he endeavours to assign the solid form of the
cluster and its dimensions, in terms of the distances
(204.)
1 Its plane is inclined about 63° to the Celestial Equator: its nodes are in 0h 47m and 12h 47m of Right Ascension.
2 In his Synopsis of the Universe, a rare work. See Professor De Morgan’s account of Wright, in the Philos. Magazine
for 1848, xxxii., p. 241. Wright believed that the Milky Way was a congeries of stars of a particular form, which it owes to
a rotation of the whole round some central point.
3 Another remark, perhaps, deserves to be recorded. Had Hipparchus and his followers been deterred by the threatened
charge of impiety from making a catalogue of stars, how great the loss would have been, not to science alone, but to our esti¬
mate of the order and magnificence of creation. The telescope only increased our knowledge of the number of worlds, without
really enabling us to approach to their limits :—the gauges of Herschel, which he at first supposed to reach to the boundary
of the visible firmament, proved to him at last that the wealth of creation was unfathomable by any measure he could apply to it.
“ Numbers numberless” appeared in those regions where the stratum of the Milky Way is most extended.
4 Etudes d}Astronomic Stellaire.
Chap. III., § 2.]
ASTRONOMY.—SIR WILLIAM HERSCHEL.
845
(hypothetically uniform) between any two stars. But
in his later memoirs, Herschel seems to have felt the
insecurity of his conclusions, and that there is no
reason, but the contrary, to believe in a uniform dis¬
tribution of the stars; that, at least in some direc¬
tions, the Milky Way is unfathomable, or its limits
unattained even by the 40-feet telescope. (See his
Memoir of 1817.) He therefore judiciously recurs
to photometrical measures as the best criterion of the
distance of the stars. The estimate of “ the space-
penetrating power” of his telescopes, already referred
to (182), enabled him to infer the relative distances at
which a star would become lost to vision aided by
each telescope.
(205.) Calling the distance of a star of the first magni-
Rclatiyc tude 1, and supposing that light takes three years to
distances or x 1
fixed stars. uavcrse  
Dist. Light travels in
36 years.
2,700
6,912
10,308
The distance of a star of the sixth mag¬
nitude (the limit of unassisted vision)
will be  12
Limit of 20-feet telescope (used in gaug¬
ing)    900
Limit of 40-feet telescope 2,304
Limit of Lord Rosse’s telescope (6 feet
diameter)  3,436
Yet none of these telescopes appear to touch the
boundary of our nebula in the direction of its greatest
extension, for fresh optical power still yields fresh
harvests of stars.
(206.) a direction perpendicular to the plane of the
All visible Milky Way, not only is the paucity of stars remark-
stars be- able> })Ut We seem to look out, as Sir John Herschel
system*of ° describes it, into a starless region external to the stra-
the Milky turn. Sir W. Herschel concluded, in 1817, that the
Way. depth of the stratum in its least dimension is such as
to include all stars down to those three times more
distant than the naked eye perceives. His son, 20
years later, infers, from the investigation of the
southern hemisphere, that the distribution of stars is
comparatively independent of direction for all those
which are brighter than the 8th magnitude, and that
it is by the influence of the hosts of lesser brightness
visible in the 20-feet reflector, that the very remark¬
able law of condensation towards the plane of the
Milky Way takes effect. He is therefore disposed to
conclude that “ our system is plunged in the sidereal
stratum constituting the Galaxy, reckoning from the
southern surface to a distance which corresponds to
the light of a star of the 9th or 10th magnitude.”1 2
These great and arduous enquiries occupied Sir (207.)
William Herschel during nearly the whole of his
scientific career, extending to almost half a century.
His first observations (Struve remarks) dated from
1774, his last observations on this subject which have
been published were of 1804, and his latest paper,
still on the same topic, was in 1821, when he was
almost on the verge of the grave.
Excepting the continuation of his labours by his (208.)
illustrious son, little has been added to our know- Continua-
ledge of “ the constitution of the Heavens” since his Herschel’s
death. We shall, therefore, hardly recur to the topic researches,
in the latter part of this chapter. Some German
astronomers of eminence have indeed tried to deduce
from an assumed distribution of the stars in the Milky
Way, the necessity of allowing that space is not per¬
fectly transparent, and have even attempted to assign
the law of extinction of light through the sidereal in¬
tervals ; but having examined their reasoning with
the best care I have been able to give it, I am
bound to say that it appears to me very far short of
conclusive.3
IV. Of the Motion of our System in Space.—That (209.)
the stars are not fixed, but have “ proper motions,” Proper mo-
not explicable by the gyrations of our earth round its tlons of
centre of gravity (which produce precession and nuta- naiiey
tion), nor by its revolution round the sun (on which
aberration and parallax depend), was a fact first de¬
tected by Halley from a comparison of ancient and
modern observations. Though small in amount, yet
as it continually increases in the same direction, this
Proper Motion becomes in the course of ages an im¬
portant quantity. In 2000 years, Arcturus, ^ Cas-
siopeise and 61 Cygni have moved 2 J, 3 J, and 6 times
the moon’s diameter.
In 1748, Bradley (in his paper on Nutation) stated (210.)
the probable explanation of these apparent motions
1 These startling results appear to be necessarily true, if the following assumptions he admitted :—(1.) That the stars have
on an average the same brilliancy in all regions of space. (2.) That the light received from a star is inversely as the square of
the distance; or that the laws of radiation and of vis viva are rigorously true, and that there is no absorption of light in space.
(3.) That the visibility of a star is exactly as the quantity of light received from it in the telescope. Probably this last assump¬
tion is the least sure. We know that magnifying power (independently of illumination) affects the result.
2 Cape Observations, p. 383.
3 I ought perhaps to state that in this passage I have referred to the reasonings of M. Struve, contained in the latter part of his
Etudes d’Astronomie Stellaire. Having taken some pains to follow the argument of that work, which professes to be “ based en¬
tirely upon observation, without any arbitrary hypothesis,” I was reluctantly led to the conclusion that M. Struve’s assumptions,
if tacit, were not the less arbitrary and questionable. Indeed it appears self-evident that no geometrical certainty can be at¬
tained as to the relative distances of the stars composing the Milky Way, but from some fundamental hypothesis respecting their
magnitudes and distribution. lam persuaded that the popular writers and reviewers who have given additional publicity to
the most striking and positive of M. Struve’s conclusions, have (very naturally) done so on the strength of the author’s well-de¬
served reputation as an observer, and without attempting to analyse his reasoning, which it must he owned is sometimes obscure.
My objections to M. Struve’s argument were put in writing several years ago (1850), but not published except in my lectures.
It was only whilst correcting the proofs of these sheets (1855) that I saw for the first time a memoir by Professor Encke in the
Astronomische Nachrichten, vol. xxvi., No, 622 (published in 1848), maintaining the same view of the invalidity of M. Struve’s
reasoning, and questioning the hypotheses (of which M. Encke reckons/ve) tacitly assumed by him. The Dutch Academy of Sciences
(Haarlem) has proposed the points at issue between MM. Struve and Encke as the subject of a prize question.
846
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
Motion of to be the real displacement of our sun and system in
the solar space. In 1760 Mayer gave a list of 80 stars whose
system in pr0per motions he determined by a comparison of
Bradley  Homer’s observations. He conceived the possibility
Mayer. of determining the direction of the solar motion by
the changing aspect of the constellations, keeping in
view, however, that the effect is complicated by real
independent movements of each individual star.
Lambert and Mitchell entertained similar views, but
carried them to no practical result.
(211.) Here, then, Herschel appears on the field. He
SirW. Her-proceeded in 1783 to do what his predecessors had
mines the discussed the 'possibility of doing. His own observa-
direction tions were not available in a problem like this. Tak-
of motion. jng best values he could obtain of the Proper
Motions of only about 20 stars, he, with great saga¬
city and success, divined that the solar system is
moving somewhere in the direction of X Herculis, a
point in the heavens whose right ascension is 257°,
and north declination 25°. This result he arrived at,
almost without calculation, by a mere consideration
of the changing perspective of a multitude of ob¬
jects amongst which the spectator moves. Mayer had
compared the change to that seen when we walk
slowly through a grove of rather distant trees. Those
in front will seem to widen or expand as we approach,
those behind will condense towards the point we are
quitting. The greatest proper motions will be in the
objects on our right and left as we advance. It is
not to be supposed that we find in the stars the exact
counterpart of this change of place. For each star
may by its own absolute movement in space either
conspire with or oppose the motion due to perspec¬
tive. But a combination of the whole results will
make apparent the direction of that part of the motion
due to a common cause, that is, to the translation of
our system in space. A cleverer approximation than
HerschePs was never made. He returned to the sub¬
ject in 1805, but there is reason to think that his
first result was the more correct.
(212.) As nothing essential has been added to Herschel’s
More recent discovery of the direction of the solar motion, we
orfthe'same s^a^‘ ^ere refer once for all to the important confir-
subject. mations which it has since received. Professor Ar-
gelander, availing himself in 1835 of the improved
state of astronomy since Bradley’s observations were
made, and since their reduction by Bessel, considered
the whole problem in a general and geometrical
manner, including every well-determined proper mo¬
tion1 by means of appropriate equations of condition,
which, being resolved by the method of least squares,
give the direction of solar motion 261° IP of right
ascension, and 30° 58' of north declination, differing
respectively about 4° and 6° from HerschePs first
numbers. Perhaps a still more convincing confirma¬
tion was obtained by Mr Galloway [Phil. Trans. 1847),
from the proper motions of stars of the southern he¬
misphere alone, which lead to a result nearly coin¬
ciding with the above.
Sir William HerschePs leading discoveries in Side- (213.)
real Astronomy may therefore be reduced to these— ofH™ary
the discovery of binary systems of stars and the orbits schel’s dis-
of several revolving stars ; the discovery and classifi- coveries.
cation of a prodigious multitude of nebulae; the law of
grouping of the entire visible firmament, and its con¬
nection with the great nebula of the Milky Way; and
lastly, the determination of the fact of the motion of
our sun and system in space, and the direction of
that motion. Setting aside all that is valuable, in¬
genious, and noble in his farther speculations, and
all that he contributed to the enlargement of our
knowledge of the system of sun and planets with
which we are more immediately connected, these po¬
sitive discoveries will ever remain a magnificent tro¬
phy of his perseverance and success as a natural phi¬
losopher.2
When his increasing years rendered the relaxation (214 )
of his arduous course of telescopic observation ad-
visable, whilst all his other faculties were in the vations.
highest vigour, he began to devote more attention to
physical enquiries less directly connected with astro¬
nomy. The nature of the emanations of light and heat
proceeding from the sun was a matter on which he
was forced to speculate in connection with his ideas
of the sun’s constitution ; and even the practical en¬
quiry as to the kind of dark glasses best fitted for
defending the eye in observations of that nature, led
him, in conformity with his usual habit, to a large
series of experiments on solar heat, and its trans-
missibility through glasses of different colours, and
other bodies. In the progress of these he was led He^tlo”gthe
to examine the heating power of the different rays of spectrum. ’ jj
the spectrum, and consequently the refrangibility of
heat. lie then arrived at the real discovery that the
place of greatest heat in a spectrum formed from the
sun’s rays by a flint-glass prism is considerably be¬
yond the extreme visible red ray. But we shall re¬
turn to this result in connection with the history of
radiant heat. He also made some experiments on
* A small star in Ursa Major (1830 of Groombridge's Catalogue) has an annual proper motion of 6"‘97 ; the star 2151 Pup-
pis, is the greatest known, being 7"-g7.
No historian of science, or biographer of Sir W. Herschel, can fail to acknowledge with gratitude the important assistance
afforded by MM. Arago and Struve to a compendious acquaintance with his writings and discoveries; the former by his article on
Herschel in the Annuaire du Bureau des Longitudes for 1842, the latter in his JEtudes d'Astronomic Stellaire. While acknowledg¬
ing my’obligations to these works, I shall not be suspected by any careful reader of having dispensed with a reference to the
original memoirs; still less of having adopted without examination the conclusions of these eminent authors, from whom, indeed,
on some important points, I differ entirely.
Chap. III., § 3.]
ASTRONOMY.—BESSEL—MR AIRY.
847
the colours of thin plates, but to these he did not
attach much importance.
(215.) The philosophical character of Herschel is almost
Herschel’s included in what precedes ; hut we will endeavour
character; to sum ft up [a a few wor(Js> jje unftecl in a re_
markable degree the resolute industry which distin¬
guishes the Germans, with the ardour and constancy
of purpose which has been thought characteristic
of the Anglo-Saxon. From his native country he
brought with him a boldness of speculation which
has long distinguished it, and it is probable that he
had also a vigorous and even poetic imagination.
Yet he was ever impatient until he had brought his
conjectures to the test of experiment and observation
of the most uncompromising kind. He delighted to
give his data a strictly numerical character. Where
this was (by their nature) impossible, he confirmed
his descriptions by reiterated observation, in different
states of weather, with different telescopes, apertures,
and magnifying powers ; and with praiseworthy fide¬
lity he enabled his readers to form their own judgment
of the character of his results by copious and literal
transcripts from his journals. On his claims to
originality we are unable in all cases to decide, owing
to almost his only literary fault, that of rarely al¬
luding to the writings of his predecessors or con¬
temporaries, even so far as to acknowledge their
existence. The discovery of binary systems is pro¬
bably that which was most absolutely his own ; but
even supposing the speculations of Wright, Lambert,
and Mitchell were not unknown to him, this would
diminish but little the substantive merit of having
devised and executed the means of removing them
from the regions of almost metaphysical abstraction
to that of concrete reality.
His long and tranquil but ever active life corre- (216.)
sponded happily to the nature of his pursuits, which his !ong
required an absolute devotion of his time, and thellfe’
means of instituting comparative observations after
an interval of many years. There are not many
philosophers who could have expected within their
lifetime to see at least one pair of suns complete
their mutual orbit.
Herschel’s career at length drew to a close. He (217.)
died peacefully at Slough, near Windsor, where fieandde'
had resided throughout the greater part of hisLease'
life, at the age of eighty-three, on the 23d August
1822, one year only after the publication of his latest
memoir in the Transactions of the then recently
formed Astronomical Society, of which he was the
first President.
§ 3. Bessel—Mr Aiey—Modern Observatories. Fixed Star Catalogues—Planetary and Lunar
Observations.
(218.) As we approach the most recent period of the his-
Modern as- tory of astronomy, I feel the increasing difficulty of a
details”0^ (^ue condensation and selection of the interesting mat-
since 1810. ^er which claims our notice. Astronomy has been so
generally and so zealously cultivated, that it seems
almost invidious to select a few names and a few lead¬
ing discoveries as the topics of discussion. It is,
however, necessary to do so, and I shall be guided by
the single aim of trying to specify impartially those
individuals who have by their labours given most of
the impress of the age to the science which they re¬
present. In a subject like this, of almost infinite de¬
tail, the reader is not to expect a list of the names of
all discoverers and improvers ; it is not our business
here to dwell upon mere labours of precision, to which
so large a part of the most useful industry of astro¬
nomers is devoted ; but to show the spirit in which
these labours must be undertaken, and the general
results by which they enrich the knowledge of the
passing generation.
(219.) In the first section of this chapter we have sketched
in England s^e accurate astronomy in fixed observatories,
down to about the year 1810. Since that period the
multiplication of observatories has been very great.
There has been a great improvement in instruments
and in the methods of using them. But there has been
an incomparably greater advance in the methods of ex¬
tracting trustworthy results from observations made
with due care. The art of dividing instruments wTas
carried to great perfection in Great Britain by Graham
and Bird, but their preference of the quadrant to in¬
struments of a circular form (introduced long before
by Romer) retarded the progress of astronomy. Fo¬
reign observatories in the early part of this century
(as in the last) sought their divided instruments from
London ; Piazzi and Bessel worked with English
circles. Troughton was as an artist the worthy suc¬
cessor of Ramsden; and even to the present time
British astronomers, at least, do not admit that the
nice contrivances and beautiful workmanship of Rep-
sold and of Merz in Germany, or of Gambey in
France, have produced instruments worthy of more
confidence than those which have been constructed
at home. In the improvement of object-glasses for
telescopes, however, Germany and France bear away
the palm, although for many years Dollond supplied
Europe with his achromatic telescopes. With regard to
constancy and fidelity of observation, whether in fixed
observatories or in maritime and geographical expe¬
ditions, English astronomers have never been back¬
ward ; and the reputation of Greenwich Observatory
in this respect (and also in the punctuality of pub¬
lication) has, as we have stated elsewhere, earned the
approbation and gratitude of all Europe.
But here our praise of British astronomy must (220.)
848
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
Keduction pause. Until very recent times, with few exceptions,
ofobserva- our observers, however industrious, have merely
Defected' USG(l mechanically the apparatus put into their hands
negec e , ^ intelligent and conscientious artists, who yet,
never having occasion to apply their own handiwork
to the purposes for wThich it wras made, could not he
expected to detect deficiencies of construction, nor
to possess the mathematical knowledge required to
remedy them. To determine in a complete and inde¬
pendent manner the errors, not only of adjustment,
hut also of construction of the instruments, and to
correct them hy calculations (deduced when neces¬
sary from frequent observations of their amount) is
now felt to be the duty of the astronomer himself.
This improvement (though, as wTe shall see, already
partially practised even in England) was mainly due
to Bessel, whose name we have placed first at the head
of this section. But astronomy owes to him much
more than this. He first showed that it is part of
an intelligent astronomer’s duty, not only to observe
stars and planets, hut to undergo the vastly greater
labour of comparing his results with the best theories
of his time, and of improving as far as possible those
theories, so as to hand over each branch of science to
his successor in a more perfect state than that in
which he found it. In all these respects practical
astronomy commenced a new epoch in. Germany, and
on this account principally we place the name of
Bessel in a conspicuous rank.
(221.) Friedrich Wilhelm Bessel was horn at Minden
Bes®el~his on the 22d July 1784. He wras destined for a mer-
boara.^ cantile career; and it is an interesting fact that it was
the expectation of an appointment as supercargo on
a commercial voyage which led him to study naviga¬
tion and astronomy, and finally induced him to de¬
vote his entire energies to the latter science, in which
he received every encouragement from the amiable Gi¬
bers, who fortunately inhabited Bremen, where young
Bessel was engaged in business. He commenced his
astronomical career hy reducing Harriott’s observa¬
tions of the comet of 1607, and was thereafter ap¬
pointed assistant to Schrdter at the observatory of
Lilienthal. In 1810 he was removed by the Prussian
government to the charge of the observatory about to
he erected at Konigsherg, where he spent the re¬
mainder of his life, and which he very speedily raised
hy his labours to almost the first rank of European
observatories. In fact, he possessed, in a singular
degree, the qualifications for directing a great obser¬
vatory ; including a thorough acquaintance with the
use of instruments, with the theory of astronomy in
all its branches, with the higher mathematics, and also
the art and practice of calculation, as well as with
many allied branches of natural philosophy.
(222.) The work by which he is perhaps best known, the
His Funda- Fund amenta Astronomies, is not grounded on his own
tronomice: observations, nor even those made in the same cen¬
tury, nor in his own country, but, what may appear
singular, upon the observations of Bradley at Green¬
wich in 1750 and some following years. In reality,—reduc-
no better observations had been then made. The in-tion of
struments had undergone no material change during 3
the long and industrious, though not splendid, career tions.
of Maskelyne; and Bradley was beyond question the
most accomplished astronomer of the 18th century.
Let us record it as a fact for the encouragement of
conscientious labour in the service of science, that
these precious records of the state of the heavens, of
which the value seemed unknown to a whole succeed¬
ing generation (so that they were not even printed
in a crude form until nearly fifty years after they
were made), were disinterred, so to speak, by an
illustrious foreigner, and in course of time made the
basis of what, in respect of precision and method,
might be called a new astronomy. Bessel was as¬
sisted in this work by a grant from the British Board
of Longitude.
The observations especially considered by Bessel (223.)
are those of the fixed stars. To apprehend their im- Special oi>-
portance, we must recollect that the foundation of anJ^,sk°f this
accurate knowledge of the orbits, and of the pertur¬
bations of the Solar System, not to mention less ap¬
parent but not less remarkable changes of place in
the stars themselves, consists in rendering perfectly
comparable observations of position at one time with
those made at another more or less remote. Now,
not only are our transit instruments and quadrants,
and circles, and clocks, affected with errors more
or less unknown, so that the registered figures re¬
quire correction; but, in consequence of Befraction
and Aberration, we see no body whatever exterior
to the earth in its real visual position ; and this
visual position, when found, is affected by Parallax.
Besides all this, the grand points of reference in
the sky, the Pole and the line of Equinoxes, are
undergoing perpetual, though small, changes of po¬
sition :—the first star of Aries had already, in the
time of Hipparchus, wandered from the point of in¬
tersection of the Equator and Ecliptic;—consequently,
longitudes and right ascensions have to be reckoned
from a directional line in space altogether imaginary.
The pole of the heavens wanders amongst the stars, in
consequence of Nutation—the obliquity of the Ecliptic - j fl
is itself changing; and, to crown all these causes of per¬
turbation and seeming unsteadiness, the stars called
fixed have (as we have formerly seen) peculiar and
individual displacements not accounted for by any of
the preceding causes of change. In short, nothing is
fixed and comparable, except our measure of time.
The length of the sidereal day is subject to no secular
variation. The bases of Astronomy,—the Funda-
menta Astronomies,—then, evidently consist in the
perfect evaluation of all these varying elements, so
that the stars, if not really fixed, may become, for us
at least, virtually so,—that by their aid the position
of the fundamental directional lines of the sphere
may at any time be found, and the relative positions
of the stars themselves. After this it is easy to
Chap. III., § 3.]
(224.)
Results.
(225.)
Bessel’s
own obser¬
vations.
(226.)
His numer'
ous works
on astrono¬
my.
ASTRONOMY.—BESSEL—MR AIRY.
849
refer tEe places of wandering bodies to standard
points.
Bessel’s work includes a methodical reduction of
the places of above 3000 stars observed by Bradley,
and an investigation of the sun’s apparent path, to¬
gether with a full discussion of the principles and
application of every correction, instrumental and
uranographical, which such observations require, and
which are applicable to all others of the same kind.
It includes, therefore, dissertations on some of the
most delicate points of Astronomy, and “ Constants”
for the different corrections, which, with slight varia¬
tion, have been since employed in every observatory.
Bessel devised also a remarkably simple mode of find¬
ing for each star the varying corrections of its place.
The proper motions of the stars were also determined
for the first time with approximate exactness, by
comparing Bradley’s places with more modern ob¬
servations.
In subsequent years (the Fundamenta were pub¬
lished in 1818) Bessel contributed to the science of
astronomy numerous and regular observations of the
heavenly bodies; the Annals of the Konigsberg
Observatory were regularly published from 1814,
being (I believe) the first foreign establishment
which followed the example set by Maskelyne at
Greenwich, with the important addition of systematic
reduction.
Of the subsequent labours of Bessel we must speak
' very shortly. The determination of the parallax of
the star called 61 Cygni, perhaps the most original
and important of these, we shall refer to another sec¬
tion, where we shall compare it with the results ob¬
tained by other astronomers. He made interesting
physical observations on Halley’s comet at its return
in 1835; he prepared the materials for a very ex¬
tended catalogue of fixed stars, arranged in zones,
more recently published by Professor Weisse. In
connection with the theory of the pendulum as a
measure of gravity, he repeated and extended Newton’s
important experiments on the uniformity of the gra¬
vitating force on all kinds of matter ; he applied a
new correction to the vibrations of the pendulum, and
improved the method of observing them correctly;
and he discussed with his habitual mathematical skill
and elaborate perseverance the figure of the Earth,
from the whole of the then existing' observations;
whilst he also directed an operation for connecting
the Russian triangulations with those of western
Europe,—a delicate task, which he performed with
consummate skill. It will thus be seen that (without
mentioning a host of minor works and memoirs) there
was hardly a great department of Astronomy in which
Bessel did not take a distinguished part. Even the
discovery of Neptune, by calculation from the irregu¬
larities of Uranus, was contemplated as a practicable
problem by the veteran astronomer in his later years.
He died on the 17th March 1846 ; therefore only a
few months previous to the publication of MM. Le¬
von. i.
verrier and Adams’ discoveries, and their triumphant
consummation by M. Galle.
Even before Bessel’s career as an astronomer had (227.)
properly commenced, Pond, in England, had antici-
pated, in a good measure, the improvements in prac- mer-Royal,
tical astronomy to which we have referred in the an excel-
beginning of this section. Already, in the earliestlent ob‘
years of this century, he had made observations at his
private residence with a comparatively small circular
instrument by Troughton, which led him to detect the
gradually increasing errors of Bradley’s quadrant still
in use at Greenwich, and to recommend the adoption
of complete circles (disused since the time of Romer)
and the specific examination of errors of division.
These principles he carried out at Greenwich, to which
establishment he was afterwards appointed. His very
indifferent health prevented that incessant activity
which the management of a first-rate observatory re¬
quires; nevertheless, he is justly regarded as one of the
chief reformers of the practical astronomy of those
days.
His successor, Mr Airy, has distinguished himself (228.)
by a more active career. Endowed with very un- Succeeded
common abilities, and with great physical powers of
endurance, he has, from his youth, been ever foremost
not only in promoting, in every one of its departments,
his favourite science of Astronomy, but also many
other allied subjects, particularly Optics, to which we
shall have occasion to refer in another section.
Born in the county of Northumberland in 1801, (229.)
Mr George Biddell Airy acquired great distinction Hls nijmer-
at Cambridge, where he graduated in 1823, and was ^physical*
appointed to the charge of the Observatory there in and practi-
1828, after the death of Professor Woodhouse, a per- cal astro-
son sincerely attached to astronomy and well skilled in nomJ'
it, yet one who did not succeed in imparting much in¬
terest either to its theoretical or practical departments.
Mr Airy engaged in the important investigation of a
new irregularity in the motion of the Earth and
Venus, to which I have referred in the chapter on
Physical Astronomy (114), and at the same time he
undertook to publish his own Observations in regular
annual volumes, including a complete comparison
of the results with the best tables, thus presenting
at a glance the existing errors of theory. This prac¬
tice he introduced at Greenwich on succeeding Pond
there in 1835; and he has pursued it ever since.
But not contented with rendering the annals of the
National Observatory a correct reflection of the state
of the heavens in his own day, and also of the con¬
dition of Astronomical Theories, he did not rest until
he had performed for the observations of his prede¬
cessors the same service, and thus produced a series
of comparisons of the observed and calculated places
of the moon and planets, unexampled for extent and
accuracy. Beginning with Bradley’s Observations
in 1750, he investigated and applied all the instru¬
mental and uranographical corrections to each, as
Bessel had done for the observations of the sun and
5 p
850
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
fixed stars, and then calculated the tabular places for
the same instants of time. This last, especially in the
case of the moon, was a truly formidable task. The
whole labour was methodically performed at the
expense of government by a staff of no less than six¬
teen computers, under Mr Airy’s vigilant superin¬
tendence, and it extended, first and last, over the
space of a dozen years. The results, printed in the
most compendious form, fill 2200 quarto pages. One
consequence of this systematic reduction was, that
MM. Leverrier and Adams were separately provided
with the places and errors of the Tables of Uranus
necessary for their great investigations; and the
Lunar Theory has been enriched with Mr Hansen’s
latest corrections through the same facilities. The
final corrections of the co-efficients of the Lunar
Tables are concisely stated by Mr Airy in a paper
addressed to the Royal Astronomical Society.
(230.) Like Bessel, Mr Airy is thoroughly acquainted
The new wJth the theory and practice of mechanics ; and he
Transit1C ^as aPP^e(l knowledge both to the improvement
Circle. of clocks and of proper astronomical instruments. A
great and apparently successful experiment of the
latter description is now taking place at Greenwich.
A meridian circle (combining in effect a mural circle
and transit instrument) has been erected, of great size
and optical power (6 feet circle and 8|- inch object-
glass). But the novelty of the apparatus is its great
weight and strength. Hitherto artists and astro¬
nomers have sought to avoid the evils of unsteadi¬
ness and flexure principally by the elaborate framing
and trussing of light materials (chiefly brass tubes),
and (in Germany especially) by an elaborate system
of counterpoises. The new Greenwich circular in¬
strument is constructed of as few pieces as possible,
of great strength and weight, and in great part of
cast iron. The whole was elaborated and prepared
for dividing in an engineering workshop, and with
the powerful and accurate tools which modern engi¬
neers use. A man might stand upon the axis with¬
out producing the smallest bad effect. It is under¬
stood that the result is perfectly satisfactory as to
steadiness and stiffness. Mr Airy has likewise in¬
vented and erected a new and most ingenious zenith
tube (acting by reflection) for ascertaining the place of
y Draconis, a star which, at its superior culmination,
crosses the meridian of Greenwich almost in the zenith.
(231.) There are few projects for the improvement of
astronomy in the last twenty years in which Mr Airy
has not been a counsellor or participator. He haslntroduc-
at all times given efficient aid to those engaged in thetionof gal'
pursuit of science; and has been himself the first to im-
port from America and to establish on a great scaleservation at
the method of recording observations by means of aGreenwich.
galvanic pressure produced on a sheet of paper sur¬
rounding a cylinder; which cylinder is moved in a per¬
fectly uniform manner by means of a connection with a
clock producing uniform motion on the principle of
the conical pendulum. By means of a simple contri¬
vance the tracer follows a slightly spiral line, so that
one barrel may include many hours of continuous ob¬
servations. He has also established galvanically time
signals, and employed them for the determination of
longitudes. Besides all this, he has taken part in
furthering geodetical measures, in regulating the
national standards of length, and in promoting in
various ways the collateral sciences. He contributed
to the Encyclopedia Metropolitana a most able
analysis of the methods for determining the Figure
of the Earth, and his conclusions have been very
generally adopted. In the same publication he has
given a theory of the Tides, already referred to (78,
82). The public and his own university are indebted
to him for several very valuable text-books on mathe¬
matical physics.
During his incumbency at Greenwich, Magnetical (232.)
and Meteorological Observations have been added Ma^netlcal
to those of Astronomy, and engage the time of four ^oroTogi-
regular assistants in that department. The astro-cal obser-
nomical assistants amount to six, besides occasionalvations-
computers. It may safely be affirmed that there is
not a public establishment in a more complete state
of efficiency than is Greenwich Observatory at this
moment; and that its traditional reputation, ex¬
pressed in the emphatic eulogium of Delambre, Art.
(150), runs no risk of deterioration under the direction
of Mr Airy.
Our limits will not allow us to refer to the nu- (233.)
merous private observatories in England and public 0ther ol?'
ones abroad which are contributing useful elementsServat01iea*
to the promotion of astronomy. It is not too much
to say that the activity of Greenwich has set a gene-
rally good example. The observations at Oxford
and Edinburgh have long been reduced on a syste¬
matic plan ; those at Cambridge had been already so
treated. The establishments where sidereal astro¬
nomy is particularly cultivated will be noticed in
another section.
§
4 _ Borda—Eater—Baily. The Figure of the Earth from
twn to a vacuumMr Stokes. Colonel Everest—M.
Earth. M. Foucault s Pendulum Experiment.
Pendulum Observations—“ Reduc-
Struve. Latest Measures of the
(234.) In the first section of this chapter I have men-
Figir0 of tioned the progress made in determining the figure
resumed °f J116 earth b? measurements of its surface in the
early part of this century. I shall now advert
briefly to the employment of the pendulum for the
same purpose.
Clairaut had published in 1743 a very remarkable (235.)
theorem which connects the force of gravity in any
Chap. III., § 4.]
ASTRONOMY.—BORDA—KATER—BAILY.
851
Connection latitude with the compression of the terrestrial ellip-
andThe^ so^-1 ^^e pendulum is the readiest and most accu-
figure of rate means of determining variations in the force of
the earth—gravity ; the repetition of its oscillations enabling
Theorem 8 tlie ol,server to ascertain their average duration with
extreme nicety. The more rapid the oscillation the
greater is the force of gravity, because the heavy
body is more quickly drawn into its lowest posi¬
tion. Two sets of observations, made in different lati¬
tudes, would, rigorously speaking, suffice to deter¬
mine the polar compression, supposing the earth to
be a geometrical ellipsoid, and composed of homoge¬
neous and concentric layers ; a larger number would
serve to test the accuracy of these assumptions, and
would, at all events, he imperatively required to
eliminate the errors of observation.
(236.) It might he supposed that to swing a pendulum,
Early pen- count its vibrations, and measure its length, is a
servations. very easy Experience shows that a more
difficult practical problem can hardly be proposed.
Those persons, therefore, who have in a good mea¬
sure overcome the difficulties, are to he regarded as
promoting materially an enquiry which has always
ranked amongst the most interesting connected with
astronomy. Some of the observations of the eight¬
eenth century, especially those of Lacaille at the
Cape of Good Hope and of Phipps in the Arctic
Regions, appear to have been made with much care ;
but the French astronomer Borda seems to have
given the initiative to observations of a higher degree
of accuracy, and his methods were ably carried out
in connection with the great French meridian arc,
by M. Biot, who even extended his stations to the
Island of Unst in Shetland.
(237.) Jean Charles Borda, who was born in 1733 and
^rove's The was devoted to the promotion of the
method of exac^ sciences, and contributed in an eminent degree
making to the precision attained in physics and astronomy
them. towards the close of the last century. The name of
Borda deserves a record in the history of science,
since it has been said of him, by no less an authority
than Dr Young, that “ he seems to have possessed a
considerable share of that natural tact and sagacity
which was so remarkable in Newton.” His earlier
researches were connected with hydrodynamics, and
the resisted motion of projectiles; in later years he
was chiefly devoted to practical astronomy and geo¬
desy. The portable repeating circle invented by him
has had a very great reputation in France. He was
one of the principal designers of the measurement
of the French arc, and was employed in its superin¬
tendence, especially as regards the measurement of
the base. His experiments on the pendulum were
originally undertaken (I believe) in 1790, with a view
to making it the basis of the national measures, hut
were afterwards subordinated to the greater scheme
of terrestrial measurement. Baily records a fact
connected with Borda, not unworthy of mention, as a
caution to observers :—the year in which many of
his experiments were made is not discoverable from
the account of them, though the day, hour, minute,
and second, are recorded with praiseworthy fidelity.
From this time pendulum experiments assumed an
astronomical and geodetical importance. The appa¬
ratus of Borda consisted of a slender metallic wire,
attached at one end to a knife-edge suspension, and at
the other to a small brass cap, nicely fitted by grind¬
ing to a sphere of platinum which formed the boh or
weight of the pendulum. The oscillations were counted
by the method of “ coincidences,” that is, by placing
the experimental pendulum in front of a good clock
with a known rate, and observing after how long a
time the two pendulums (having started in the same
direction) again coincided in their motions by one of
them having gained or lost exactly two vibrations;
a method wdiich has been used at least since the
time of Bouguer. The time of vibration being thus
known, the distance from the knife edges to the bot¬
tom of the hall was measured by means of a scale ;
and due corrections for the position of the centre of
oscillation were then applied.
By English observers, an invariable pendulum of C23?-)
the form of a flat bar, provided with a bob or weight,
has usually been preferred, and on the whole it ap- PeD U Um
pears to he more satisfactory. Such a pendulum,
after being compared with an astronomical clock at
Greenwich, or any other place of reference, is taken
to different stations and its rate of vibration deter¬
mined, and it is then brought back and compared once
more at the point of starting. Important series of
observations of this kind have been made by Colonel
Sabine and Captain Foster, and also by Admiral Du-
perrey.
But the two individuals who have most studied
the practical determination of the length of the se- an/ablo-
conds pendulum as a mechanical problem, are Kater lute mea-
Laplace 1 Clairaut (besides giving a theorem which, in the case of an ellipsoid, connects the polar compression with the increase of
and Mr gravity there) showed that the increase of the force of gravity from the equator will vary as the square of the sine of the lati-
Stokes on tude. This he proved to be true when the spheroid is homogeneous, or when it is composed of similar concentric layers of
the earth’s varying density. Laplace confirmed the result by a different analysis, and farther showed, that if the earth be composed of con-
attraction. centric strata which are severally homogeneous, and nearly spherical, but otherwise arbitrary in form, and if the surface be that
of a fluid in equilibrium (as it practically is when we refer the earth’s figure to the sea-level), there exists a necessary connection
between gravity and the superficial figure, which, in the case of an ellipsoid of revolution, leads to the same relation of the square
of the sine of the latitude. In this case, also, the strata are presumed to be concentric. But in a recent and remarkable paper
by Professor Stokes, it is shown that the law connecting the force of gravity and the figure of equilibrium still holds when no hypo¬
thesis whatever is made as to the distribution of the matter within the earth, provided always that it be consistent with the observed
fact of the ellipsoidal figure of the earth’s fluid covering. Thus the confirmation, by means of pendulum experiments, of Clairaut’s
Theorems cannot be regarded as a proof of the concentric arrangement of the strata, nor (so far) of the primitive fluidity of
the earth. See Cambridge Transactions, vol. viii.; and for a simpler proof, Cambridge and Dublin Math. Journal, vol. iv. p. 194.
852
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(240.)
Captain
Kater;
his con¬
vertible
pendulum.
(241.)
His Colli¬
mator.
(242.)
Francis
Baily;
his early
history
and Baily. As regards the determination of the
Earth’s figure, the relative length of a pendulum vi¬
brating seconds in different latitudes is all that is re¬
quired ; but the absolute length in a given place is
necessary for finding the force of gravity there ex¬
pressed by the acceleration of falling bodies in vacuo
in one second ; and as the British standard yard was
at that time made to depend on the length of the pen¬
dulum vibrating seconds at London, this enquiry was
mixed up with the intricate one of National Standard
Measures.
Captain Henry Kater was a person of remarkable
mechanical skill and ingenuity, and his numerous pa¬
pers in the Philosophical Transactions, between 1813
and 1828, refer chiefly to the accurate construction
and use of the Pendulum, the Balance, and certain As¬
tronomical Instruments. He first applied to practical
use the beautiful theorem of Huygens respecting the
convertibility of the Centres of Oscillation and Sus¬
pension of the pendulum. A metallic bar pendulum
was provided with two parallel knife-edges facing op¬
posite ways, and upon either of which it might be
swung. They were so arranged that when either was
used as the point of suspension, the other nearly re¬
presented the centre of oscillation, and by means of
a small adjustable weight, this condition might be ac¬
curately fulfilled; in which case (by Huygens’ princi¬
ple) the distance between the knife-edges corresponded
accurately to the length of an equivalent simple pen¬
dulum. This elegant application was farther tested
by Mr Baily, but it was found liable to serious prac¬
tical objections. Baily dispensed with the sliding
weight, and rendered the pendulum invariable: the
distance of the knife-edges was adjusted by grinding.
To Kater we owe the invention of the floating Col¬
limator, for ascertaining the accurate zero or level
points of divided astronomical instruments. The op¬
tical principle on which it depends is a very beau¬
tiful one, and the invention of Kater, with several
improvements in point of form, has become the auxi¬
liary of nearly every observatory in the world. It is
one of those small but happy improvements which
affect materially the progress of Science.
Francis Baily, who was born 28th April 1774, and
who died 30th August 1844, was an instance of a
person not endowed with extraordinary talents, yet of
singular use in his generation. Those who knew Mr
Baily personally, and what he accomplished for Astro¬
nomy, are best aware how rare and yet how estimable
are such qualifications as his. Born of parents of a
middle rank of life, educated at a country school, and
at an early age thrown into the vortex of commer¬
cial life in the city of London, no probability could
have appeared more remote than that he should ac¬
quire the respect of even the most accomplished As¬
tronomers by his scientific acquirements and perform¬
ances. He enjoyed the advantage, in the first place,
of a perfectly sound and uninterrupted state of health
until his 70th year. His intellect partook of the
equable tone of his bodily powers. Method, and an andcharac-
ardour which, instead of acting by impulses, seemedter*
inexhaustible and unvaried, were the secrets of his
success. Mr Baily never was hurried, and he never
was unemployed. He had always leisure to encourage
men of like tastes, and he was never unwilling to learn
from any one who had knowledge to communicate.
To do one thing at a time was his first principle.
When thoroughly accomplished, it was completely put
aside, and a fresh subject undertaken. Whether an
experiment or a calculation was found to require a
month or three years, it was pursued to a successful
completion, without stint or grudging. No amount
of contrariety and failure in such matters was ever
known to ruffle his temper, or to make his persever¬
ance falter.
Francis Baily was known, in the first place, as the
founder (in 1820) of the Astronomical Society °f th^Astro-
London, an institution of signal utility, which has nomical
ever since been conducted with great judgment and Society,
success. His accurate knowledge of past and current
astronomical history, and his personal acquaintance
with most European astronomers, enabled him to
conduct its affairs with great advantage.
Amongst his other acquirements, he studied his- (244.)
tory and chronology with his customary precision. A
very able paper on the date of the celebrated Eclipse and gtar
of Thales was his earliest scientific publication,1 and Catalogues,
the literature and phenomena of solar eclipses occu¬
pied his particular attention ever afterwards. His ac¬
counts of the Eclipse of 1820, of the Annular Eclipse
of 1836, which he observed at Jedburgh, and the Total
Eclipse of 1842, with its marvellous revelation of the
rose-coloured protuberances of the solar atmosphere,
are among the most interesting and classical of his
writings. He promoted greatly the formation and
publication of accurate Star Catalogues, and he in¬
vented, independently of Bessel, constant numbers
for facilitating the calculation of Precession, Nuta¬
tion, and Aberration, as affecting the places of parti¬
cular stars. He also published a most useful collec¬
tion of Astronomical Tables and Formulae, and an
elaborate and very curious life of Flamsteed.
I shall now proceed to notice his experiments on (24 a
the Pendulum, which are more particularly connected
with the present section. .
Mr Baily’s most important observations were on g
a correction of the motion of a pendulum long mis- pendulum
understood. The corrections usually admitted were observa-
the following:—-1. For temperature altering thetl0n3*
length of the pendulum. 2. For the height of the
station above the level of the sea. Dr Young showed
that this correction was commonly overrated, owing
to the sensible amount of the attraction of the ele¬
vated land on which the experiment is made. 3. For
1 Phil. Trans. 1811.
Chap. III., § 4.] ASTRONOMY.—BAILY—COLONEL EVEREST—M. STRUVE.
853
the air’s buoyancy. The mere resistance of the air
to the motion of the pendulum may be shown to pro¬
duce opposite and compensating effects in the descend¬
ing and ascending semi-vibrations : but the presence
of air, as of any other fluid, diminishes the total ef¬
fect of gravity on the bob, and that in a degree de¬
pending on the density of the air or atmospheric
pressure. But besides this obvious “ reduction to a
vacuum,” it appears that the air acts also in a dif¬
ferent way. Owing to its inertia and cohesion a
portion of air is shoved along with the pendulum,
or otherwise put in motion by it, and the force
thus spent in moving air is not compensated during
Reduction the two semi-vibrations. This effect was clearly as-
toava- certained and measured by Dubuat about 1786, and
described in the second edition of his “ Principes d’PIy-
drauliquebut it appears to have been totally un¬
observed by his own countrymen and others, who
(like Borda) were soon after actively engaged with the
same subject. The effect was experimentally re-dis¬
covered by Bessel, and made the subject of an admi¬
rable series of experiments by Baily, which were pub¬
lished in the Philosophical Transactions for 1832.
He vibrated pendulums of different forms in vacuo
and in air (as Colonel Sabine had done to a more
limited extent shortly before), and he ascertained the
corrected “ reduction to a vacuum” to be in many in¬
stances double of the old correction, and to depend
materially on the form and density of the pendulum.
It even appeared that when a convertible pendulum
is swung in two positions in the manner of Kater,
the correction is different in the two cases, owing to
the want of symmetry, so that a pendulum convert¬
ible in air of a given density is not convertible in va¬
cuo, nor vice versa.
Bessel and Baily agree in imputing the effect to
the clinging of a mass of air to the metallic pendu¬
lum, thus rendering it in effect a pendulum of much
less density, for which the ordinary correction for
buoyancy will have to be increased. This view is
probably rather a popular than an exact expression of
the fact, and the correction need not be always pro¬
portional to that of buoyancy. Poisson has treated
the question mathematically, and Professor Stokes
has recently resumed the whole subject, both mathe¬
matically and practically, and considers that he has
arrived at precise mathematical results in several
cases. The result may probably be a revival of inte¬
rest in pendulum observations, which has manifestly
very much declined since the existence of this irregu¬
larity has been fully established, and the incompe¬
tency of existing rules for “ reduction to a vacuum”
clearly shown.
In 1833, Baily deduced from the very elaborate
experiments of Captain Foster in both hemispheres
for the earth’s compression. Colonel Sabine had
(247.)
Investi¬
gated by-
Bessel and
others.
Mr Stokes.
(248.)
Result as
to Earth’s
oblateness,
found it froin Ws own observations. The French
and Russian observers concur in obtaining a result
sensibly greater. Of these experiments, Captain Fos¬
ter’s is by much the most extensive. Mr Baily’s re- The Caven-
petition of Cavendish’s experiment for determining
the earth’s density, has been mentioned in a previous
section.
In conclusion of the subject of the figure of the (249.)
earth deduced from observation I shall now briefly Recfn* ,
refer to the results ot geodetical measures more re- measures:
cent than those noticed in the first section of this —Colonel
chapter, which comprehended the great French arc.
In a matter so much of detail, which will he bet- 1
ter appreciated from special articles in the Encyclo-
pcedia, I shall best fulfil the ends of this discourse,
by merely directing attention to the two most con¬
spicuous and important of these measurements of
the earth, one in India, the other in central and
northern Europe ; the first directed by Colonel Eve¬
rest, the second by M. Struve, the eminent astrono¬
mer of Pulkowa.
The measurement of an arc of the meridian in In- (250.)
dia by Colonel Lambton in the early part of this cen-
tury, has been mentioned in a former part of this rest-s jn.
Dissertation, as well as in Sir John Leslie’s. But its dian arc.
value has been prodigiously increased by the exten¬
sion of the same by Colonel Everest, who was at one
time the principal assistant and coadjutor of Colonel
Lambton. The arc of Lambton, extending from Punnae
(Lat. 8° 9' 35") to Damargida (Lat. 18° 3' 15"), was
measured after the model of the English trigonome¬
trical survey, by means of a 100-feet steel chain for
the base, a 3-feet theodolite for the azimuths, and a
5-feet zenith sector for latitudes. Colonel Everest
pursued the triangulation in a northerly direction for
some years after the death of Lambton in 1823;
but losing his health, and being forced to return to
Europe, he was provided, by the princely munificence
of the East India Company, with an entirely new set
of instruments, and with two able assistants, Cap¬
tains Waugh and Renny.
He resumed operations in 1832, which were con- j2,151-),
tinued until 1840, and included an entirely new ^*crulties
measurement of an arc extending from Damargida, which it
where Lambton’s arc terminated, to Kaliana (Lat. was exe-
29° 30'48"), a space of 797 miles, covering an arccuted'
of 11° 277 33". The latest geodetical improvements
were introduced. The bases were measured by Ge¬
neral Colby’s compensating bars, in which the effect
of temperature is self-corrected. The signals from
station to station were made during the day by he¬
liotropes reflecting the solar ray parallel to the sides
of the triangles to be measured. The azimuths were
determined by a 3-feet theodolite of Troughton, in
addition to that of Carey used by Lambton; the
astronomical observations were made with two circles
of large dimensions. The difficulties and annoyances
experienced in conducting so vast a work, requiring
such excessive accuracy, in so remote a situation,
can only be judged of by referring to Colonel Eve¬
rest’s graphic details contained in his elaborate ac-
854
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
count of it, published at the East India Company’s
expense in 1847. The heats and the rains, the
dull opake atmosphere of the Doab, with its bound¬
less and densely-wooded flats, the jungle fever and
the wild animals, were natural impediments enough.
But Colonel Everest, whose conscientious anxiety
reached almost a nervous pitch, seems not to have
been satisfied with any one instrument which the
mechanicians of London could produce ; but to
have metamorphosed most of them, partly with his
own hands, partly by native aid. It says much for
his ability in this respect, that the results appear
entitled to compete with ail the most exquisite of the
kind in Europe. His bases, for instance, about 7i|
miles in length, when checked by intermediate trian¬
gulation above 400 miles in extent, differed in one
instance by 4, in another by 7 inches from the pri¬
mary measurement. The whole extent of Lambton’s
and Colonel Everest’s operations includes a continu¬
ous arc of 21° 21' (1477 miles), by far the greatest
at that time executed.
(252.) It is indeed only rivalled in this respect by a vast
Russian arc operation very lately executed in Russia and other
^ northern countries of Europe, by which an arc of 25°
20', extending from the banks of the Danube to the
shores of the Arctic Sea, near the North Cape, has
been measured under the general superintendence
and direction of that able astronomer M. Struve,
whose meritorious labours in other departments of
astronomy will be specified in a succeeding section.
The results are still incomplete, though the opera¬
tions in the field were happily concluded just in time
to prevent their total frustration by the unhappy war
in which Russia has since engaged.
(253.) The arcs of India and of Russia include a space
Its extent. from 8° to Lat. 71°, with the exception of only
about sixteen degrees, and are unquestionably the
most important which exist for the determination of
the earth’s figure. When to them we add the French
arc of 12° 22' in a medium latitude, it will scarcely
be necessary to take into account any other, at least
for the Northern Hemisphere.
(254.) The following brief details of the Russian arc are
taken from the provisional report of M. Struve(1852).
(255d The southern extremity of the Russo-Scandinavian
th^ Russo- arc ^ Ismail on the Danube (Lat. 45° 20'), the north-
Scandina- 6rn extremity is Fuglenaes on the island of Qualoe
■vian Arc. in Finnmarken (Lat. 70° 40'). The interval from
Tornea to Fuglenaes (4°49')was measured bySwedish
and Norwegian engineers; all the remainder by those
of Russia, and, in particular, by M. Von Tenner, who,
with M. Struve, has since 1816 directed the whole
operation. The whole line is remarkably free from con¬
siderable inequalities of ground, and from mountain
ranges, so that local attractions are probably incon¬
siderable.1 On the other hand, extensive forests ex¬
tending over dead flats have, in the southern part of
the arc (as in India), occasioned great difficulties, and
compelled the erection of numerous temporary struc¬
tures to overlook the country. In the north the
extraordinary refractions have, as usual, created some
difficulties. Ten different base lines, all at a small
height above the sea, form part of the operations.
It is a very satisfactory circumstance, that by the
care of M. Struve and Mr Airy, the standards of
length used in the Indian and Russian arcs have
been directly compared.
The calculation of the figure of the earth from the (256.)
completed Russian arc, in combination with others, General re-
has not yet been made, but it is believed that it ^»
will indicate an ellipticity somewhat greater than ellipticity
that generally received. The results obtained by Co- from geo-
lonel Everest, on the other hand, by comparing hisdesyj
arc with those of Europe, give generally small ellip-
ticities, that is under The French and Indian
arcs, for instance, give 3^. Now Mr Airy had de¬
duced 20 years ago from the best existing observa¬
tions g-Jg-; Bessel, a few years later, obtained the al¬
most identical result of and Schmidt of g^r.
The determinations by means of the pendulum are and from
somewhat larger. The extensive observations of Co- pendulum
lonel Sabine and Captain Foster concur in giving exPen_
• • • ^ merits.
an ellipticity of 5 but the French experiments by
Duperrey and Freycinet lead to a result considerably
greater. The discrepancy between the geodetical and
pendulum results may of course be a real one de¬
pending on local variations of density. The astro¬
nomical determination from the lunar inequalities,
which might be expected to concur with the results
of the pendulum, gives (as we have seen in the chap¬
ter on Physical Astronomy, Art. 63) 3^ at a mean.
I regret that my limits do not permit me to speak (257.)
of the measure of degrees of longitude or arcs of pa- British arc
rallel, as another test of the earth’s figure. The re-° "
suits, however, cannot compete in point of certainty
with those from arcs of the meridian. It may be sa¬
tisfactory to add, that the British arc of parallel from
Greenwich to Valentia (west coast of Ireland) sen¬
sibly accords with the earth’s figure obtained inde¬
pendently.
In connection with the subject of the pendulum (258.)
treated in the earlier part of this section, I shall here Fou'
,. iii caults pen-
mention a very remarkable experimental observation duium ex_
communicated to the Paris Academy of Sciences, on periment,
the 3d February 1851, by M. Leon Foucault, to
whom we also owe some ingenious experiments on
the velocity of light. It is not indeed connected with
the determination of the earth’s figure, but it has a
connection with astronomy, inasmuch as it affords the
most remarkable and direct proof of the earth’s rota¬
tion round its axis.
1 In India, on the contrary, the local attractions of the Himalaya must he very sensible; indeed Mr Pratt has calculated them
to be so considerable, as to have given rise to a curious speculation by Mr Airy as to the circumstances which may tend to
diminish the attraction of mountain ranges.—(Phil.Trans. 1855.)
Chap. III., § 5.]
ASTRONOMY.—M. FOUCAULT—M. ENCKE.
855
(259.) Suppose a considerable weight suspended by a wire
demon- of regular elasticity from a fixed point or stand con-
f6nected firmly with the ground; and let us first ima-
tation. g'ine tbe place ot the experiment to be exactly over
the North Pole. Let the wire pendulum be swung
so as to coincide with the plane of the meridian of
London. As the earth rotates, the wire and the ball
must evidently rotate too. But the motion of the
mass originally impressed parallel to a given plane
will continue in that plane, and consequently the
plane of motion will coincide in the course of 12 hours
with every meridian in succession, and the apparent
rotation will be entirely completed in a uniform man¬
ner in 24 hours. In any other latitude than 90°,
but greater than 0°, a continuous and regular appa¬
rent change of motion must also occur, since a me¬
ridian of the globe does not preserve its parallelism
during diurnal motion, excepting only at the equator;
consequently, at all points of the earth’s surface, ex¬
cept at the equator, the plane of motion of the pendu¬
lum will vary uniformly in azimuth—quicker, how¬
ever, in high than in low latitudes. To find this
velocity, it is only necessary to decompose the rota¬
tion of the earth round its axis into two, one of which
(which is alone effective) is round the vertical of the
place of observation. The apparent angular motion
is thus proportional to the sine of the angle of lati¬
tude. Thus, in an hour, it is 15° x sine lat.
M. Foucault’s experiment was made, in the first in- (260.)
stance, with a pendulum of steel wire from 'OS to -05 Corrections
inch in diameter, bearing a ball of 12 pounds weight.
It is desirable to make the pendulum vibrate in small
arcs, in consequence of the tendency to ellipticity in
the vibrations, which is necessarily accompanied by a
rotation of the major axis of the ellipse, which might
easily be mistaken for the influence of the earth’s
motion. To take account of this disturbing force,
we have only to measure accurately the greater and
less axes of the ellipse described. Then a revolution
of the apsides (from this cause only) will be per¬
formed in a time which will be found by multiply¬
ing the time of a double vibration of the pendulum
by 8 times the square of the length of the 'pendulum,
divided by 3 times the product of the two axes of the
ellipse. This formula is due to Mr Airy. The theory
of M. Foucault’s beautiful experiment has been
verified by numerous experiments in different la¬
titudes.
Very recently the theory of the motion of a pen- (261.)
dulum suspended by a thread or wire has been con-
sidered in the most general manner by M. Hansen, gated by M.
the physical astronomer, with reference to the earth’s Hanseu.
motion.1 It is an intricate problem of analytical
mechanics. But the results show, as might have been
anticipated, that all the sensible results are those which
the geometrical treatment of the question indicate.
§ 5. M. Encke. Cometary Astronomy—Periodic Comets of Halley and Encke. Gambart’s and
Biela’s Comet—Comets of 1811 and 1843. Mr Hind—New Planets or Asteroids. Mr Las-
sell—Newly discovered Satellites. Mr Bond.
(262.)
Professor
Encke.
Periodic
Comets.
(263.)
Halley’s
Comet—
period 76
years.
Professor Johann Franz Encke, Director of the
Observatory of Berlin, is one of the most eminent
physical and practical astronomers of the present day.
The author of many valuable observations and im¬
portant memoirs, he is best known by those which
are connected with the motions and theory of Comets.
I shall therefore devote this section to an abstract of
the progress of this interesting subject, and more
particularly of M. Encke’s discoveries and specula¬
tions. I must premise, however, that, easy and
agreeable as it would be to introduce here a detailed
essay on Cometary Astronomy, the design and extent
of this discourse alike forbid it, and at the cost of
some self-denial, I will endeavour to confine myself
entirely to what is most new and characteristic in the
Cometary history of later years.
Halley^ Comet.—Before proceeding to describe
the remarkable comet especially connected with the
name of Encke, it will be proper to resume the his¬
tory of Halley’s Comet where it has been left off by
Sir John Leslie in his Dissertation. That Comet—
the comet of 1682—must ever remain memorable,
perhaps the most so of its class, as being the first
whose return was confidently predicted, in firm reli¬
ance on the Newtonian Theory of Gravity. Halley’s
announcement—grounded not on vague analogies,
but on laborious computations—that it would reap¬
pear early in 1759, was realized almost to the letter; Its return
and Clairaut, whose surprising analytical ability oftenin D59.
left but little to his successors to accomplish, calcu¬
lated the perturbations with an accuracy which even
the present state of physical astronomy has hardly
exceeded. Indeed no general method for calculating
perturbations in highly elliptic orbits is as yet in use,
and though the methods of Clairaut have been super¬
seded by those of Lagrange and Bessel and Lever-
rier, the summation of the effects by the method of
“ quadratures” is always used,—the periodic time of
the comet being divided into short intervals through¬
out which the elements are considered invariable, and
during which the configurations and perturbing effects
of the principal planets are computed with much
labour.
The chief improvement in the calculation of per- (264.)
turbations is the introduction by Lagrange of the cele¬
brated method of the Variation of the elements (44.)
1 Theorie der Pendelbewegung. Dantzig, 1853.
856
MATHEMATICAL AXO PHYSICAL SCIENCE.
[Diss. VI.
Its pertur- His successors have distinguished themselves chiefly
bations praiseworthy minuteness and extent of their
balCvarious calculations, which are amongst the most laborious,
aJtrono- if not indeed the most laborious, which occur in Phy-
mers. sical Astronomy. The computers who calculated
the return of Halley’s Comet in 1835 were four in
number, MM. Damoiseau, Pontecoulant, Lehmann,
and Rosenberger. Their memoirs are all considered
by competent judges to be excellent, but especially
that of Rosenberger, who calculated more fully than
the others the perturbations from 1682 to 1759, and
who has introduced a theoretical correction of some
importance. Some idea of the extent of these calcu¬
lations may be formed from the fact, that in some
parts of the orbit the Elements were made to vary
for intervals of only two days. The Comet of Halley
was rediscovered at Rome on the 6th August 1835,
in the Jesuits’ College. The error of Rosenber-
ger’s Ephemeris was only seven minutes of arc, and
the perihelion passage took place on the 16th No¬
vember (civil reckoning), five days after the predicted
time. Bessel states the remarkable fact, that the coin¬
cidence of the comet’s path with the results of previous
calculation is as close as the use of five-place loga¬
rithms in computing the perturbations would permit.
All this is very creditable to the state of Astronomy;
still it is infinitely less remarkable than Clairaut’s
approximation, only a little less close, made 77 years
before. It is a matter of regret that neither in the
matter of this comet, nor in any other point of theory
connected with Cometary movements, have our coun¬
trymen made any considerable advance since the time
of Halley.
(265.) At its return in 1835, this Comet was watched
in91835™ May 1936, and in the course of its long visibi¬
lity was made the subject of minute and admirable
telescopic researches, by Bessel in Europe, and by
Sir John Herschel at the Cape of Good Hope. Their
observations strictly confirmed a remark of M. Valz,
that the Tails of Comets, though evidently generated
under the influence of the neighbourhood of the Sun,
yet commonly disappear at the period of closest ap¬
proach. This, at least, was the case with Halley’s
Comet. The tail began to grow on the 2d October,
two months after its discovery, and diminished after
the 15th (a month before perihelion). The cometre-
appeared in the end of January without any vestige of
a tail, and then dilated in absolute bulk with in¬
credible quickness. But before its final disappear¬
ance, on the 5th May, the tail is supposed to have
Its peculiar teen reabsorbed into the nucleus, which presented
features, then a uniform circular outline. The evolution of
the highly-expansible luminous matter of the tail
took place from the nucleus in luminous fan-like
jets, directed on the whole towards the Sun, and
issuing on the side of the Comet exposed to that
body. The jets had a vibratory motion. The tail
(directed/row the Sun) was formed by the abrupt
inflexion of these effluent jets, in a manner resem¬
bling electrical repulsion; and Sir John Herschel has
not hesitated to ascribe the phenomenon to the com¬
bination of a repulsive force as respects the Sun,
(“ of an energy very far exceeding the gravitating force
towards that luminary”) with “ a peculiar and highly
energetic attraction to the nucleus, differing from,
and exceptional to, the ordinary power of gravita¬
tion.”1 The opinion that polar forces resembling
magnetism or electricity are necessary to explain the
phenomena of Comets, has been for some time cur¬
rent in Germany, and received, I believe, the coun¬
tenance of Bessel. That there exist in the movements
of these bodies anomalies so great as to render the
sufficiency and completeness of the Theory of Gravity
suspected by such high authorities, makes the state¬
ment of them very important, though I confess a
great reluctance to share in the conclusion.
I shall terminate this notice of Halley’s Comet
with a table of the dates of its probable perihelion reaturen°
passages, according to M. Laugier and Mr Hind.2
The earlier appearances are deduced from the Chinese
Annals:—•
Date.
B. C. 11-80
a.d. 66-07
141-24
218-26
295-25
373-84
451-50
530-84
608-80
684-80
760-44
837-26
912-25
Interval.
Years.
77-87
75- 17
77- 02
76- 99
78- 59
77- 66
79- 34
77-96
76-00
75- 64
76- 82
74-99
Date.
A.D. 989-70
1066-25
1145-30
1223-52
1301-81
1378-85
1456-44
1531-65 (o.s.)
1607-82 (n.s.)
1682-70
1759-19
1835-87
Interval.
Years.
77»45
76- 55
79-05
78-22
78-29
77- 04
77-59
75- 21
76- 14
74-88
76-49
76-68
The differences in the above periods are attributed to
the effects of perturbation. The extreme distance of
the Comet’s path from the Sun is 351 times the ra¬
dius of the Earth’s orbit, which is only one-sixth part
greater than the distance of Neptune, and therefore
nearly within the recognized limits of the planetary
system. y.
Comet of Encke.—Next in interest to the Comet
of Halley is that discovered by Pons of Marseilles Encket
in November 1819, which was first suspected, then
proved by Professor Encke, to revolve in an elliptic
orbit of short period (considerably interior, in fact,
1 See Sir John Herschel’s Outlines of Astronomy, and Results of Observations at the Cape of Good Hope.
2 Taken from Mr Hind’s small work on Comets.
Chap. III., § 5.]
ASTRONOMY.—M. ENCKE—GAMBART.
857
to the orbit of Jupiter), and made the subject by
him of a series of investigations altogether peculiar.
On this account it hears the name of Encke, instead
of that of its discoverer Pons, although M. Encke
himself, with unaffected modesty, always describes it
as the Comet of Pons.
(268.) Newton gave, in the Principia, his celebrated so-
orbitVde- ^u^on the problem of determining a Comet’s orbit
rived from assumed to be parabolic, from three geocentric places,
observa- This solution has been simplified and improved by
Lagrange and Boscovich, and also by Olbers. La¬
place gave a method for an elliptic orbit, which may
represent any number of observations. Gauss, in
his Theoria Motus Corporum Celestium, treated the
subject with great skill and generality. I am unable
to state who first attempted to discriminate an ellip¬
tic from a parabolic cometary orbit, or to determine
the period in the former from observations at one ap¬
parition only. It is evident that such outstanding
differences as are irreconcilable with a parabolic
orbit, will be most perceptible in the case of comets
whose orbits have a tolerably short major axis, or
whose period is not very great, and will be mate¬
rially increased by watching a comet through a con¬
siderable part of its orbit, which the assiduous appli¬
cation of telescopes to every part of the heavens has
of late years rendered much more frequent than for¬
merly. Amongst others, Bessel, who has signalized
himself by a capital performance in this, as in every
other department of Astronomy, applied rigorous me¬
thods to determine the orbits of the comets of 1807 and
1815 ; the latter of which will very probably return
to its perihelion in 1887. It is undeniable, however,
that expert calculators have often been deceived in
assigning orbits, even when believed to be of short
period, founded upon a single apparition.
(269.) M. Encke, however, was more fortunate in the case
M. Encke’s 0f comet of 1819. Using the methods of
on theCheS Gauss> he showed that an Elliptic Orbit of about 3^
comet of years must be admitted, and that the comet had pro-
1819—pe- bably been already observed in 1786, by Mechain, in
years'^ 1795 by Miss Herschel,1 and in 1805 by Pons. He
investigated with great labour the effects of the planet¬
ary perturbations on this body, which, in the case of
Jupiter, are occasionally very large, if that planet be
in the part of its orbit near the aphelion position of
the comet, when it approaches the orbit of Jupiter.
The careful calculations of M. Encke for the next re¬
turn in 1822 were verified by the observations of Sir
Thomas Brisbane, at that time fortunately governor
of New South Wales, where he had, with character¬
istic liberality, founded an Observatory. Since then,
this body, insignificant in its physical appearance
(being to all appearance a small cloud of vapour
without a solid nucleus), has been detected in one or
another part of the world at every revolution: —
namely, in 1825, 1828, 1832, 1835, 1838, 1842, t*5 appa-
1845,1848, and 1852; so that the Comet has beenrltl0ns*
observed at fourteen (not all consecutive) returns.
The complete establishment of the existence and pe- (270.)
riodicity of a comet, quite in the interior of the planet- ratea^
ary system (its greatest distance from the Sun being tion
four times the Earth’s distance, and its least distance
but one-third of the Earth’s), was a discovery in itself
highly interesting. But something yet remained be¬
hind. Professor Encke, in comparing the earlier with
the later apparitions of the Comet, detected a gradual
acceleration of its movement, which amounted be¬
tween 1786 and 1838,to 1-8 days,on a period of about
1211 days; being about 2b hours per revolution.
Whatever may be the cause of this, the fact is undis¬
puted, even by Bessel, who was indisposed to accept
M. Encke’s explanation. This fact, it will be observed,
is unique in Astronomy. The major axis and periodic
times of the planets and satellites have, as we have
seen in the chapter on Physical Astronomy, no secu¬
lar variation. The moon’s apparent acceloration has
been otherwise accounted for. M. Encke at once, attributed
and at an early period, attributed the acceleration of resist*
the Comet’s mean motion to the effect of a slightly
resisting medium, insensible in the case of the planets,
partly owing to their incomparably greater density (for
this Comet appears to be one of the most loosely ag¬
gregated bodies known, being transparent to its very
centre); and also, to the circumstance, that the density
of the ether or resisting medium is assumed to dimi¬
nish rapidly at a distance from the Sun. M. Encke
supposes it to decrease in density with the square of
the distance, and only to affect the Comet sensibly
within 25 days preceding or following its perihelion.
That the effect of resistance is to accelerate the return
of the Comet is evident, by considering that the pro¬
jectile force becoming gradually extinguished, the
Sun’s attraction must be more available to pull the
body inwards at each revolution, thus shortening the
major axis of the ellipse, and diminishing the time.
In order satisfactorily to arrive at any such con- (271.)
elusion, it was of course necessary to estimate with
great accuracy the perturbing effects of the planets Encke’s
on the Comet’s motion; and it is not a little curious comet ap-
and satisfactory, that the movements of this insigni- PIied to
ficant erratic body should have occasioned a mate- masses of6
rial rectification of the masses of two of the Planets. Mercury
M. Encke very early suspected that the receivedan(i J11?**
mass of Jupiter was too small, a fact clearly esta-ter‘
blished afterwards by Mr Airy; and in 1838 M. Encke
showed that the mass of Mercury (which, not having
a satellite, was little more than guessed at previously)
had been assumed nearly three times too great by La¬
grange. The perihelion of the Comet approaches much
Miss Caro- 1 ^aro^ne Lucretia Herschel, sister of Sir William and aunt of Sir John Herschel, deserves a passing notice, not only as the
line Her- independent discoverer of eight comets (of which five were first seen by her), hut as the indefatigable and intelligent assistant of
schel William Herschel during the busiest years of his life. For this service King George III., carrying out his judicious liberality
to her brother, granted her a small pension. She died at Hanover 9th January 1848, aged 97.
VOL. I. 5 Q
858
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
more nearly to the orbit of Mercury than the aphelion
does to that of Jupiter; consequently at times the
perturbations due to the former planet may be very
great, and though the gravitating mass of the Comet
is utterly unknown, yet since the momentary direc¬
tion of its motion depends solely on the ratio of the
attractive force of the Sun and Mercury, its observed
course gives the means of estimating that ratio.1
(272.) The theory of a resisting medium was, on the whole,
Theory of well received, especially in England, where some of
a resisting our first authorities gave it their adhesion. The then
altogether1 recent establishment of the Undulatory Theory of
favourably Light, was thought by many to receive a confirmation
received, from this evidence of something material filling the
planetary spaces. In Germany the hypothesis of re¬
sistance received the complete opposition of Bessel’s
high authority ; who declared that “ a hundred other
reasons” might be found for the fact of the accelera¬
tion, which he admits to be true. Encke, in reply,
reduces these 100 possible hypotheses to four, of which
we shall mention only one, as seemingly important,
namely, the forces exerted with so much intensity
within the body of the Comet itself, as indicated by
the projection of the tail. But he observes, with great
sagacity, that these forces, being apparently usually
excited in the line of the radius-vector joining the
Comet and the Sun, can hardly be supposed to affect
the periodic time. It having also been objected that
Halley’s Comet shows no trace of acceleration, but, if
anything, of the reverse, M. Encke truly says, that
its perihelion distance does not lie within the assumed
limits of the denser ether.
(273.) Nevertheless, the theory of a resisting medium in
and still space is not perhaps very popular, except in England,
questioned. Although M. de Humboldt appears to favour it, I
understand that the German astronomers in general
scarcely regard it as in any degree proved.
(274.) Yet, if not true, the cardinal fact remains unex¬
plained. The anomalous phenomena of the Tails of
Comets, considered by Herschel to be altogether inex¬
plicable by the law of gravity, demand the closest
scrutiny ; and one can hardly help supposing that
the two difficulties may be in close connection. As
the Newtonian law is now considered (since the dis¬
covery of Neptune, and the latest corrections of the
Lunar Tables) to be absolutely sufficient to account
for everything connected with planetary motion, the
Astronomy of Comets will be looked to with increas¬
ing interest, as likely to reveal some laws of nature
not otherwise to be detected. In this respect, Pro¬
fessor Encke’s labours are likely to be more and more
important in their results,
(275.) With reference to this very eminent astronomer,
M. Encke we have only to add, that he has for a great many
bationsUr" years ^ecn at °f the Observatory at Berlin,
and in that capacity has published an Astronomical
Ephemeris of first-rate excellence. It is as a phy¬
sical astronomer, however, that he will be principally
remembered. Besides his admirable investigations
connected with the Comet, he improved the theory of
Vesta, and has very lately published a new Method
of Computing Perturbations, especially for orbits con¬
siderably elliptical. Neptune was discovered at his
Observatory, by the assistant astronomer, M. Galle.
G-ambart's and Biela's Comet.—Jean Gambart, (276.)
one of the most promising astronomers in France, died
of consumption at a comparatively early age, I believe ^metre a 8
in 1836. He was director of the Observatory at Mar¬
seilles, which, notwithstanding its very unfavourable
position in the midst of the town, has acquired con¬
siderable celebrity as regards the discovery and obser¬
vation of Comets. Pons, by whom Encke’s Comet was
found, both in 1805 and 1818, conducted the Ob¬
servatory ; but its mounting was as bad as its situa¬
tion, and Pons used despairingly to describe his tele¬
scope as rather 'paralytic than parallactic. To this
crippled establishment M. Gambart succeeded, and by
his skill in managing his defective instruments, and
by his patience in sweeping for Comets, he discovered
and subsequently computed the orbits of a number of
these bodies between 1822 and the period of his death.
Gambart was highly esteemed, both by French and
foreign Astronomers. Pons also deserves great credit
for his extraordinary diligence in the discovery of
Comets, and M. Valz, who still directs the Obser¬
vatory of Marseilles has cultivated this and other
branches of the science with success.
Gambart’s most remarkable discovery was the pe- (277.)
riodicity of the first Comet of 1826, having detected Periodicity
that body independently at Marseilles, though it hadin Gf yeais>
been observed some days previously in Bohemia, by
Biela, an officer in the Austrian service. It is most
usually called Biela’s Comet, though it might with
equal right be termed Gambart’s, who assigned its
path and predicted its return. Clausen, about the
same time with Gambart, assigned it a period of about
7 years ; and it was identified with former appear¬
ances in 1772 and 1805-6. Its period thus appeared
to be 2460 days, or 6f years ; its aphelion is a little
exterior to Jupiter’s orbit, and its perihelion is not
much within the Earth’s. This Comet’s orbit very
nearly intersects in one place the orbit of the Earth,
so that had the earth been one month forwarder in
its annual course in 1832, a collision would have
taken place, or at least the Earth would have been
enveloped in a cometary haze; for it is difficult to
imagine a collision Avith a body whose tenuity is so
excessive, that Sir John Herschel perceived through
its entire thickness (estimated at 50,000 miles) stars
of the most excessive minuteness (16th or 17th mag¬
nitude) as seen by his 20-feet reflector. It is an in¬
teresting circumstance, that the first predicted peri¬
helion passage, in 1832, took place within some hours
of the time fixed by MM. Santini and Damoiseau,
1 On the Masses and Densities of the Planets, see Encke in Astron. Nachrichten, vol. xix., col. 187.
Chap. III., § 5.]
ASTRONOMY.—MR HIND—MR LASSELL.
859
(278.)
(279.)
Division
of the body
of the co¬
met in
1846.
(280.)
Other
periodical
comets.
(281.)
Great
comets of
1811 and
1843.
though the perturbations of Jupiter were, as usual,
large.
Biel a’s Comet has been since recognised in 1846
and 1852, but it was not seen in 1839. It does not
appear to be admitted that it shows any acceleration
due to a resisting medium. Its perihelion distance
is, however, considerable.
At the apparition of 1846 an extraordinary cir¬
cumstance occurred. When discovered in the end
of November 1845 it appeared round and single.
On the 19 th December it was observed by Mr Hind
to be elongated, and ten days later was seen in Ame¬
rica (and soon after at Cambridge and elsewhere) to
have divided into two seemingly distinct nebulous
parts.1 These continued to subsist and move inde¬
pendently throughout the remainder of the appari¬
tion : the real distance of the centres being about
150,000 English miles. In 1852 the comet was
rediscovered at Rome; the division into two still
subsisting, but the interval of separation being in¬
creased about eight-fold.
Besides the comets of Encke and Biela, there are
several others which are suspected on good grounds
to have periods of from 5^ to years, their aphelia
all lying in tolerable proximity to the orbit of Ju¬
piter. But among these the return of only one has
yet been verified by observation ; namely, the comet
of Faye, which, after passing its perihelion 17th
October 1843, returned to it 3d April 1851, within
an hour of the time predicted by M. Leverrier. The
motion of comets of short period seems to be inva¬
riably direct or conformable to that of the planets.
The inclination of their orbits to the Ecliptic is
usually moderate.
Great Comets of 1811 and 1843.—The finest
comets of the last hundred years were those of 1811
and 1843. The former was observed for a length of
time altogether unusual, having been visible from
March 1811 to August 1812. There is pretty good
reason to think that its period is not much less than
3000 years. The comet of 1843 was even more
splendid, but its flight was more rapid, and it was
not favourably seen in northern latitudes. It was
visible at many places in broad daylight when less
than 4° from the Sun, and at one time a tail 65° in
length could be traced. The circumstance which
distinguishes this comet from all others which have
been computed is the smallness of its perihelion dis¬
tance, which was only of the radius of the Earth’s
orbit, or the comet approached the Sun’s body within
one-seventh of his radius. The solar disk then sub¬
tended an angle at the comet of 121^-°, or the glare
was equal to that of 47,000 suns as seen by us !
The heat to which the comet was exposed is supposed
to have exceeded 24 times that concentrated by our
most powerful burning-glasses by which even rock
crystal has been fused.2
Mr Hind.—Discovery of New Planets.—We have .
spoken in a former section (161), of the discovery of Discovery
four small planets or asteroids between the orbits of of new
Mars and Jupiter. They were found between the years l>lanet* ,or
1801 and 1807. An interval of nearly forty years
elapsed without any addition to the members of our
system. In 1845 a new asteroid, Astraea, was found
by M. Hencke ; the following year was distinguished
by the discovery of Neptune under unparalleled cir¬
cumstances ; and since 1847 every year, down to the
present time (1855), has added to our knowledge of
the group of asteroids.
Among the discoverers of these planetary bodies
Mr Hind has been distinguished by frequent success,
under circumstances which appeared by no means
peculiarly advantageous. This indefatigable obser¬
ver and computer commenced (I believe) his astrono¬
mical career as one of the assistants at Greenwich,
and afterwards had the sole charge of the private ob¬
servatory of Mr Bishop, a wealthy citizen of London,
together with the use of a fine refractor equatoreally
mounted. It is within the Regent’s Park, close to
the smoke of the metropolis, that Mr Hind has dis¬
covered a larger number of planetary bodies than
any other person living. Next to him M. de Gas-
paris of Naples has been most successful. Unques¬
tionably the impulse towards these new discoveries
has been given by the indefatigable industry of astro¬
nomers (principally those of Germany), in constructing
minutely accurate star-maps. Mr Hind is also advan¬
tageously known by the discovery of several comets,
and by his ingenious observations in sidereal astro¬
nomy, especially on variable stars. I shall here
give a table of the asteroids in the order of discovery
as at present known (July 1855).
1 Ceres
2 Pallas
3 Juno
4 Vesta
5 Astraea
6 Hebe
7 Iris
8 Flora
9 Metis
10 Hygeia
11 Parthenope
12 Victoria
13 Egeria
14 Irene
15 Eunomia
16 Psyche
17 Thetis
18 Melpomene
19 Fortuna
1801 Jan. 1
1802 March 28
1804 Sept. 1
1807 March 29
1845 Dec. 8
1847 July 1
Aug. 13
Oct. 18
1848 April 26
1849 April 12
1850 May 11
Sept. 13
Nov. 2
1851 May 19
July 29
1852 March 17
April 17
June 24
Aug. 22
Piazzi.
Olbers.
Harding.
Olbers.
Hencke.
Hencke.
Hind.
Hind.
Graham.
De Gasparis.
De Gasparis.
Hind.
De Gasparis.
Hind.
De Gasparis.
De Gasparis.
Luther.
Hind.
Hind.
M. de Gas¬
paris.
List of the
Asteroids.
1 A similar phenomenon is related by Seneca. See Grant’s History of Astronomy, p. 302.
2 See many other interesting particulars of this comet in Sir J. Herschel’s Outlines of Astronomy, arts. 589, &c. See also in¬
teresting details on the subject of comets generally in Mr Hind’s and Mr Milne’s works on comets, and in Mr Grant’s excellent
History of Physical Astronomy.
860
MATHEMATICAL AND PHYSICAL SCIENCE. [Diss. VI.
20 Massilia
21 Lutetia
22 Calliope
23 Thalia
24 Themis
25 Phocaea
26 Proserpine
27 Euterpe
28 Bellona
29 Amphitrite
30 Urania
31 Euphrosyne
32 Pomona
33 Polyhymnia
34 Circe
35 Leucothaea
1852 Sept. 19
Nov. 15
Nov. 16
Dec. 15
1853 April 5
April 6
May 5
Nov. 8
1854 March 1
March 1
July 22
Sept. 1
Oct. 26
Oct. 28
1855 April 6
April 19
De Gasparis.
Goldschmidt.
Hind.
Hind.
De Gasparis.
Chacornac.
Luther.
Hind.
Luther.
Marth.
Hind.
Ferguson.
Goldschmidt.
Chacornac.
Chacornac.
Luther.
(284.) Mr Lassell.—New Secondary Planets.—Mr Las-
New Se- se;n 0f Liverpool deserves a more lengthened no-
TTanetT t^ce ^ian our permit, not only as a dis-
Mr Lassell. tinguished discoverer, hut as one whose success can¬
not he too widely made known as an encouragement
to others. This gentleman, engaged in mercantile
pursuits in an eminently commercial town, possessing
little leisure and no enormous fortune, has contrived,
in the intervals of business, to construct with his own
hands telescopes which in accuracy of definition ap¬
pear to rival any which art stimulated by national
liberality has yet constructed elsewhere, and to use
them with a degree of skill and success which has
not been exceeded (nor in some respects equalled)
by any astronomer whether professional or otherwise.
I speak, let it be observed, of accuracy of definition,
such as is necessary to display minute points of
light, like the satellites of ITranus. In respect of
the amount of illumination requisite for the display
of many diffuse faint objects among the nebulas, the
gigantic telescopes of Herschel and Lord Hosse are
of course superior.
. 85 . Mr Lassel’s observatory near Liverpool was erected
His instru- in 1840. The principal instrument is a reflecting
ments. telescope of 24 inches aperture (completed, however,
only some years later), mounted equatoreally, an ar¬
rangement requiring great mechanical skill, but, as
the results show, most effectually accomplished. The
speculum was worked and polished by machinery con¬
structed by Mr Nasmyth, but principally devised by
Mr Lassell, after he had examined and tried Lord
Rosse’s method. I should think it must be admitted
to be the most perfect optical work of its kind ever
made: for I believe there is no test object in existence
which Mr Lassell has not seen with it; in fact he
has discovered the most delicate tests himself,—the
6th star of the group 6 Orionis (though not first seen
by him), a satellite of Neptune, an eighth satellite of
Saturn, and several satellites of Uranus.
Not many days had elapsed after the discovery of (286.)
Neptune, before Mr Lassell, directing his telescope116 disc°-
to it, perceived a satellite (as he believed) on Oct.
10, 1846. The discovery was fully made out in the Neptune,
following year, and was soon after verified by the
great refractors of Pulkowa and Western Cambridge
(U.S.) Its period is about 5*879 days,1 and its dis¬
covery was of singular importance as leading to a
knowledge of the mass of the planet.
Till 1848 only seven satellites of Saturn were ad- (287.)
mitted. The two closest to the planet were detected and one of
by Sir William Herschel in 1789, and have beenSaturn*
seen by very few astronomers since. During five
years1 residence at the Cape, Sir John Herschel never
but once obtained even a doubtful glimpse of the
closest with an 18-inch mirror. The third, fourth,
and fifth were discovered by Cassini in 1684; the
sixth and most conspicuous by Huygens in 1654 : the
outermost by Cassini in 1671. To these an eighth
satellite, intermediate in position between the two
last, was added by Mr Lassell on the 19th September
1848. By a singular coincidence, it was recognised
as a satellite the very same evening by Mr Bond of
Cambridge (in America) with the great Munich re¬
fractor. The new body was called Hyperion, in con¬
formity with Sir John Herschel’s suggestion of distin¬
guishing the satellites as well as the planets by mytho¬
logical names. On the 22d November 1850 Mr Las¬
sell saw at once Saturn with his whole train of eight
satellites—a glorious spectacle probably enjoyed by no
other astronomer. In the same month of November Faint ring
Mr Bond discovered a faint or dusky ring of Saturn
interior to the two long known. It is probably ne- Mr
bulous, for by Mr Lassell’s observations and Mr Bond.
Jacob’s it appears to be transparent.
Sir William Herschel thought that he recognised (288.)
six satellites of Uranus. The second and fourth of Juran^.
his table have been observed by several astronomers,
particularly Sir John Herschel and M. Lament.
Their periods are 8d l7h and 13d llh. To these Mr
Lassell, aided by the fine climate of Malta (to which
for two seasons he removed his telescope), has con¬
clusively added two more : one, appearing to coin¬
cide with the closest of Herschel’s, of which the
period is 4d 3h 28m, and one still nearer the planet
revolving in 2d 12m 29s, the shortest orbital revolu¬
tion in the solar system. Mr Lassell doubts se¬
riously the existence of any other satellite.2
1 From Mr Lassell’s observations at Malta, 1852-3.
2 See Astron. Society's Notices, xiii. 151; and xiv. 133.
Chap. III., § 6.] ASTRONOMY.—M. STRUVE—SIR JOHN HERSCHEL.
861
§ 6. Sidereal Astronomy since 1820.—M. Struve—Double Stars. Observatories of Dorpat and
Pulkowa. Sir John Herschel—Orbits of Double Stars. Magnitudes of Stars. Variable
Stars. Earl op Rosse—His Telescopes. Nebulee. Henderson and Bessel—Parallax of
Stars.
(289.) As it is absolutely necessary to bring this chapter
Continua- to a speedy close, and as I have already anticipated,
history of* accoun^ °f Sir William Herschel’s discoveries,
Sidereal Par^ of what relates to the recent history of the As-
Astrono- tronomy of the Fixed Stars, particularly the “ Con¬
stitution of the Heavens,” and the motion of our
system in space, I shall condense within brief com¬
pass a few leading facts connected, in the first place,
with the Orbits of Double Stars, the Brightness of
Stars, and the constitution of Nebulas, and these sub¬
jects I shall connect with the names of the elder M.
Struve, Sir John Herschel, and Lord Rosse; the second
topic shall be the Parallax and distance of the fixed
stars, as ascertained more particularly by the late
professors Henderson and Bessel.
(290.) Friedrich Georg- Wilhelm Struve has been the
M. Struve. most assidu^g observer of double stars since the time
of Sir William Herschel. No discovery in this de¬
partment can for a moment compete with the great
one of the orbital revolution of one star round an¬
other. But M. Struve, by devoting his chief energies
during the most active years of his life, since 1813,
to the assiduous continuation of Herschel’s observa¬
tions, has added immensely to our knowledge of these
systems, and has earned the reputation of one of the
most skilful of modern practical astronomers. His
most elaborate observations were made at the Rus¬
sian Observatory at Dorpat, with a noble refractor by
Fraunhofer, nearly 10 inches aperture, and 13|- feet
in focal length. He has published three works on the
subject of double stars, one in 1824, one in 1837,
and one in 1852, besides minor papers. The second
of these works contains the particulars of about 3000
double stars, deduced from a survey of the heavens,
in which at least 120,000 stars were examined.
(291.) M. Struve’s papers are distinguished by the ela-
searches o ^ora^on ^ie reductions, and of the statistical re¬
double suits deduced from them. In his last publication he
stars. has made an interesting estimate of the number of
true double stars in the heavens, which, it appears,
is much greater in proportion to the whole number
than is usually believed. But it is first necessary to
distinguish those which are physically double from
those whicli are merely apparently or optically so.
The criteria on which he principally depends are—•
(1.) the fact of observed orbital revolution ; but as
this is established in comparatively few instances, he
very reasonably admits (2.) a common proper motion
of the two components as a proof of their connection.
He thus finds the evidence for physical duplicity to
be much stronger for the closer double stars, and also
for brighter or nearer stars, as compared with those of
less magnitude. On the whole he concludes, that of
1973 double stars, 1702, or six-sevenths of the whole,
are physically connected, and that, amongst at least
the brighter stars, the number of compound systems
is to that of isolated stars in a ratio not less than 1
to 3, perhaps even 1 to 2.
M. Struve has also determined with extreme care (292.)
the places and proper motions of the double stars Struve
and he has formed a decided opinion, that the proper
motions diminish on the whole regularly with the order
of magnitude,—thus confirming the criterion of in¬
creased distance from diminished brilliancy, by that
of the apparent displacement of the stars by the mo¬
tion of our system.
Besides these important works on Sidereal Astro- (293.)
nomy, M. Struve is well known as the head and di-Directs th9
rector of perhaps the best organized observatory in
the world, that of Pulkowa near St Petersburg, offiulkowa.
which he has published a very interesting descrip¬
tion. Besides other noble instruments, it contains
the finest refractor in Europe, that by Merz, 15 inches
in diameter, and 22 feet focal length. The observa¬
tions with this noble telescope are chiefly made by his
son M. Otto Struve, the author of many good papers.
We have seen in a former section (252), that we owe
in great part to M. Struve the conduct of the most
extensive trigonometrical operation ever undertaken.
Sir John Frederick William Herschel, son of/ (294.)
Sir William Herschel, whilst conversant with almost^1, John
every branch of science, has devoted himself with re-hisaTtrono"
markable success to the cultivation of Sidereal As-micaica.
tronomy. “ Bearing a name honoured and revered reer.
by all, his career at Cambridge reflected upon it fresh
lustre ; the variety and extent of his acquirements
gave him a reputation amongst his college contem¬
poraries, afterwards fully confirmed by the not more
impartial voice of mankind at large.” He was senior
wrangler in 1813. “ Since that time he has been
indefatigable as an author:—first, in systematizing
the higher mathematics, and in forwarding their study
in his own university ;—afterwards by treatises con¬
tributed to the Encyclopcedia Metropolitana on Sound,
Light, and Physical Astronomy, which still rank
among the clearest, completest, and most philoso¬
phical in our language. About the same time he
wrote experimental essays on different branches of
Chemistry, Magnetism, and Optics, and commenced
his purely astronomical investigations, chiefly on
nebulae and double stars, partly in conjunction with
Sir James South, of which the details are given in
different volumes of the Astronomical, and of the
Royal Society’s Transactions. These memoirs collec¬
tively include a complete revision of the objects of
the same description catalogued and classified by Sir
862
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
William Herschel.”1 But the most considerable
monument to Sir John Herschel’s love of science is
the record of his four years’ labours for the advance¬
ment of Sidereal Astronomy at the Cape of Good
Hope, where he applied his father’s methods of ob-
Sir J. Her- servation to the southern hemisphere. His Results
schel’s Ob- 0f Astronomical Observations, which fill a large quarto
atVhe Cape volume, and which include “ the completion of a
of Good 1 Telescopic Survey of the visible Heavens, commenced
Hope. jn 1825,” form one of the most considerable and
most interesting works of our time. The instruments
employed were a 20-feet reflector, of 18-J- inches aper¬
ture, and a 7-feet achromatic, with 5 inches of aper¬
ture. With these the nebulae and double stars of
southern skies wrere examined and measured, and that
wonderful “ Gauging of the Heavens” completed, of
which I have spoken in the account of Sir William
Herschel (201). There is an admirable chapter on
the apparent magnitude of the stars, to which I shall
refer presently, and one on Halley’s comet, besides
other matters of interest.
(295.) Since his return to England in 1838, Sir John
His high Herschel has withdrawn from the labours of practi-
aniongst1' ca^ astronomy, but he continues to advance different
his contem- branches of science, and to expound them by his able
poraries. and lucid writings in a way which has made his au¬
thority equally respected by philosophers and by men
of the world. The career of Sir John Herschel has
been marked by an almost total absence of the ele¬
ment of ambition, so often a powerful excitement in
the pursuit of discovery. Had he sought notoriety
and posthumous fame, he would have confined his
efforts within a more circumscribed range. But his
versatile talents sought their appropriate exercise in
all departments of exact science, and even (it is be¬
lieved) in pursuits widely distinct from these, in
natural history, belles lettres, and the fine arts. In
all this he no doubt considered simply the useful
and pleasurable employment of his mental activi¬
ties. Truth seemed to him as desirable whether at¬
tained by the labours of others or by his own; and
in his numerous writings he has expounded these
with a zest which a less generous spirit might have
reserved for his peculiar achievements. What he
may have lost in future fame by this enlargement of
his sympathies and interests, he has gained in the re¬
spect and good-will of all his contemporaries. Sir
John Herschel recently filled the post of Master of
the Mint, to which, like his illustrious predecessor
Newton, he devoted a considerable share of his time.
His general eminence as a man of science has been
acknowledged by his nomination in 1855 to the dis¬
tinguished honorary position of one of the eight fo¬
reign Associates of the French Academy of Sciences.
(296.) Orbits of Double Stars.—Though not absolutely
bks^of °r" ^ie aPPty ca^cu^atj°n t° the orbits of double
double stars, this step in their theory may not unfitly be con-
stars. —   
nected with the name of Sir John Herschel, from the
ardour of his researches and the neatness of his
methods. To Savary of Paris is due the merit of
ascertaining the form and position of the orbit of £
Ursse Majoris in 1827, which was followed by a
more purely analytical method by M. Encke, and
one chiefly graphical by Sir J. Herschel,2 in which
angles of position of the component stars are used
nearly to the exclusion of the more doubtful measures
of distance. On the whole, these investigations not
onlyconfirm Sir William Herschel’s anticipations, but
render it highly probable that the relative orbits are
really ellipses, and consequently that the law of force
is that of the inverse square of the distance. The
reader will find in Sir J. Herschel’s Cape Observa¬
tions a very curious discussion of the orbit of y Vir-
ginis, a remarkable double star, whose interval was
in 1783 five seconds and two-thirds, which diminished
till 1836, when the two stars appeared united in one,
as seen even in the best telescopes. This was the
perihelion passage of these two suns, and the angle
of position must then have varied (could it have
been measured) at the rate of 70° per annum, or 1°
in 5 days. The following are some of the best as¬
certained periods of sidereal revolutions in years :—
£Herculis 36y-4; g Ursse Majoris 61y-5 ; ocCentauri
77y ; p Ophiuchi 80 or 90y; <r Corenae Borealis 600
or 700y. M. Madler, Admiral Smyth, and Mr Hind,
have added much to our knowledge of this interest¬
ing subject.
Brightness of Stars, and Variable Stars.—Sir John (297.)
Herschel has attempted by an elaborate system of^ egg
inter-comparison to assign the correct relative bright-of ftars_
ness of the stars, and to give precision to the ordi¬
nary terminology of Magnitudes. His “ Method of
Sequences” described in his Cape Observations, ap¬
pears to be one of the happiest specimens of generali¬
zation which experimental science affords. Whilst
regretting the impossibility of here giving even the
slightest sketch of it, I cannot but recommend it to
the student of natural philosophy as a model of re¬
search. Having ascertained, in a way independent
of every sort of hypothesis, the relative brightness
of the stars upon the scale of Magnitudes usually
adopted, but which is wholly arbitrary, Sir J. Her¬
schel proceeds, by properly photometric methods, to
give a scientific precision to this notation; and he
arrives at this singular and fortunate conclusion, that
by adding a small and constant correction to the re¬
ceived scale of Magnitudes, the numbers will repre¬
sent the distances of the respective stars from our
system on the supposition of an intrinsic equality in
the brightness of the stars themselves.
This subject naturally includes that of Variable (298.)
Stars, which may be divided into those which under-
go periodic or irregular fluctuations, and the latter
class may embrace new stars, and stars which have
1 Quarterly Review, vol. Ixxxv., p. 2.
2 Astronomical Society's Memoirs, vol. v.
Chap. III., § 6.] ASTRONOMY.—LORD ROSSE—HENDERSON AND BESSEL. 863
disappeared. The last two hundred years have not
presented any such astonishing phenomena as the
new stars recorded in the sixteenth and seventeenth
centuries ; but singular variations in the brightness
of some of the most conspicuous stars, as a Orionis
and 77 Argus, have been discovered by Sir John
Herschel. Several stars of short and irregular
periods of varying brightness were recorded towards
the close of last century. But upon this very in¬
teresting subject I must content myself with refer¬
ring to the details given by Professor Argelander in
the third volume of Humboldt’s Cosmos.
(299.) Earl of Rosse. Latest observations on Nebulce.—
Lord Rosse jj. -g a remarkable circumstance, that as the reflect-
fleeting in& telescope was a British invention, so the more
telescopes, important improvements and applications of it have
been almost confined to the United Kingdom. It is
also worthy of notice that the manufacture has pros¬
pered more in the hands of amateurs than of regular
opticians. Sir William Herschel appeared at one
time to have brought the invention to its highest per¬
fection, but the Earl of Rosse has made an important
step farther ; not only by constructing a larger tele¬
scope than had been made before, but by adapting
machinery driven by steam power, to the grinding
and polishing of the mirror ; so that the largest
speculum may be finished with nearly the same ac¬
curacy and expedition as the smallest. The chef
d'ceuvre of Lord Rosse is a telescope of 6 feet aper¬
ture, and 53 or 54 feet of focal length. It was com¬
pleted in the latter part of 1844, and erected at Par-
sonstown in Ireland.
(300.) Let me here record the important fact, that neither
enTOuUltieS rank nor wealth could absolve Lord Rosse from those
tered. toils and disappointments which attend all new and
original efforts. There is no royal road to such triumphs.
The Irish nobleman owes his success entirely to his
unwearying perseverance and mechanical skill. Even
his assistants were countrymen instructed by him¬
self in his own workshops, where the very steam-en¬
gine which drives the polisher was fabricated. His
labours to improve the telescope date from 1828
(when he was Lord Oxmantown), or even earlier, and
they appear to have been unremitting until 1844; in¬
deed I might say until the present time. Com¬
mencing with a variety of ingenious attempts to cor¬
rect spherical aberration, and to overcome the ex¬
treme difficulty of procuring large castings of so ex¬
cessively brittle a material as speculum-metal, they
terminated in the rejection of all minor helps and
expedients, and in the fortunate completion of im¬
mense mirrors at a single casting, and of correctly
parabolic figure when ground and polished. The
speculum of his largest telescope weighs four tons.
It was polished in six hours, and its surface is con¬
siderably more than twice as large as that of Sir
William Herschel’s forty-feet instrument.
We cannot enter into the details of the methods, (301.)
which evince no small mechanical skill and scientific Methods of
ingenuity, together with a perseverance admirable in ^ff^truc'
itself.1 * * I will only mention how the upper and
lower surfaces of the casting were made to cool nearly
equally fast. To effect this the lower surface of the
mould (which naturally retains the heat more than
the upper) was made of iron, a good conductor, whilst
the upper surface was made of sand. This effected
the purpose; but it being found that air bubbles
entangled in the fluid metal could not escape beneath,
and injured the casting, the iron bed was constructed
of hoops set on edge and closely packed, the crevices
allowing the escape of air, whilst the cooling pro¬
ceeded as before; and this ingenious contrivance was
perfectly successful.
Many difficulties in detail have been found in the (302.)
mounting and use of so gigantic a mass, particularly 4PPlica~
on account of the distortion of the mirror by flexure. bulV'and'
But these have gradually been surmounted by Lord its results.
Rosse. His published observations (Philosophical
Transactions, 1850) relate almost entirely to objects
of the class of nebulte ; and as I cannot enter into
details, I may state the general results in two or three
sentences. (1.) As might have been expected, many
nebulae which resisted the power of former telescopes
(for, except in rare instances, nothing greater than
eighteen-inch apertures have been directed to them)
have been “resolved” into stars by the six-feet specu¬
lum. (2.) The aspect of a great number of nebulae
described by the two Herschels is materially modified
by the power of the telescope to embrace the fainter
prolongations of these singular objects. In general,
the symmetrical forms are very much cut up and
confused, and in many cases vanish altogether.
(3.) Instead of these, a certain species of symmetry,
of a vague yet very remarkable description, has been
detected by Lord Rosse, probably for the first time.
It is a spiral arrangement of the nebulous coils
round a centre, resembling somewhat the spiral
emanations of revolving fireworks. The well-known
nebula No. 51 of Messier’s Catalogue shows this
in a remarkable manner.
Some observations have been made upon the moon. (303.)
It is much to be desired that these were continued,
and that the planets could also be observed; but I
believe that the climate of Parsonstown affords but
few nights favourable to observation.
Henderson and Bessel. Parallax and distance (304.)
of the Fixed Stars.—Thomas Henderson, at one^6^^®^
time government astronomer at the Cape of Good ”^^0-
Hope, and subsequently professor of practical as-ter.
tronomy in the university of Edinburgh, and his
1 For a comparison of Lord Rosse’s and Messrs Naysmith and Lassell’s (subsequent) methods of mechanical grinding and
polishing, see Astron. Soc. Notices, vol. ix. p. 110. In Lord Rosse’s apparatus every stroke of the polisher is almost a straight
line; in Mr Lassell’s it never is.
864
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
Majesty’s astronomer for Scotland, was born at
Dundee, in Scotland, 28th December 1798. He died
at Edinburgh 23d November 1844. His career was
an instance of the conquest of disadvantages of many
kinds by a patient, devoted, and conscientious spirit,
and of the attainment of a station of great eminence
in the world of science by singleness of purpose, and
an ardent love of knowledge.
(305.) He was fortunate in having Mr Duncan (now of
Render- Andrews) as his instructor in mathematics at
tificVro-11* Dundee, and it was “ while employed as an attorney’s
gress. clerk in a provincial town that he laid the founda¬
tions of that extensive acquaintance with astronomy
for which he was afterwards distinguished.” It was
his good fortune to attract in Edinburgh the discern¬
ing notice of Sir James Gibson-Craig and his family;
through whose influence, probably, he obtained pro¬
fessional employments of a kind which permitted
him considerable leisure, and even gave him an op¬
portunity of forming scientific acquaintances in Lon¬
don. His early tastes were towards the practical cal¬
culations of astronomy, such as occultations and
ephemerides; and from his merits alone he was
commended and patronized by Dr Thomas Young.
Had that great man lived, his promotion to a scienti-
Appointed fie post would have probably been earlier. As it was,
ObservaPe obtaine(i 1831 an honourable, an<l, for him,
tory!1'11' lucrative appointment as astronomer at the Cape; at
the sacrifice, however, of quitting his native country.
In the thirteen months during which he held that
situation, he performed an amount of first-rate work
in practical astronomy which may bear a comparison
with any similar effort. Charged with an instrument
notoriously defective (Jones’s circle), he had to
examine its errors and their compensations; and
it is no small credit to him to say that with such
an indifferent tool he carried off a prize which
had been the aspiration of so many astronomers
before him—the determination of the parallax of a
fixed star.
(306.) We must not go back to the history of this pro-
Thc pariil-^ fi]ein previous to the nineteenth century, when alone
stars instruments were so far perfected as to give results
by which a parallax, or displacement by perspective
of a star in consequence of the earth’s motion had a
chance of being discovered, since it certainly does not
amount to above a second or two, probably never
attains even the former amount.
(307.) The earlier part of this century witnessed a memor-
had been aye contest on this subject between Mr Pond, the
gated by Astronomer-Royal, and Dr Brinkley, afterwards Bi-
Pond and shop of Cloyne; the former founded on observations
Brinkley.     
at Greenwich, the latter at Dublin, both with instru¬
ments of great power, being meridian circles of the
largest size. It is sufficient here to note that Dr
Brinkley attributed to some of tbe brighter stars,
such as a Lyrse, a parallax of 2"-5 (which, how¬
ever, he afterwards reduced to little more than 1"),
whilst Mr Pond could arrive at no such result. There
is no doubt that Mr Pond was correct.1
The first case of parallax which was determined with (308.)
some certainty by the use of ordinary meridional in- Tlr.en<lerson
j t 9 discovers
struments was that of a Centauri, a bright star of the that of a
southern hemisphere, which was deduced by Hender- Centauri.
son from his observations at the Cape long after they
had been made, and what is perhaps still more satis¬
factory, made without reference to this particular
question. The result, which gave to this star an
annual parallax of 0-91 of a second, is believed to be
correct, because it has been confirmed by Mr Maclear,
Henderson’s successor at the Cape. It may, however,
be not unreasonable to desire that the observations
should be repeated in another locality, and with a
different instrument; for it has not been unusual (as
in the case of Brinkley) to obtain under the same
circumstances perfectly consistent, yet erroneous, and
therefore inexplicable results.
The very considerable amount of parallax in this (309.)
instance, corresponding to a large proper motion
(3"-6), gives a strong independent probability that it
is not materially erroneous ; and in this respect the
most competent and impartial historians of science
have given full credit to Mr Henderson for having,
by superior skill in the use of his instruments, and
the happy choice of an object, made a discovery which
so many eminent observers had long sought for in
vain.
Subsequent to the date of Henderson’s observa- (310.)
tions, but before their publication, Bessel (whose Bessel’s
biography we have given in Section 3 of this chap- tiong on 61
ter) determined the parallax of the star 61 Cygni, in Cygni.
a different way. It was a happy suggestion of Galileo,
that if two stars he selected apparently near one
another, but really disconnected, and having very un¬
equal magnitudes (therefore probably at very dif¬
ferent distances from our system),—and if the ap¬
parent angular distance between the two stars be
measured from opposite parts of the earth’s orbit,
it must sensibly vary by an obvious effect of per¬
spective. It was in pursuit of this happy idea
that Sir W. Herschel discovered the fact that the
connection of such pairs of stars is often real, not
apparent—but it was Bessel who, guided in his
choice of an object by the critical character of the
Notice of
Brinkley,
Bishop of
Cloyne.
1 John Brinkley, Bishop of Cloyne, was born in England, and educated at Cambridge, where he was senior wrangler in 1788.
He acted for a short time as Maskelyne’s assistant at Greenwich, and was subsequently appointed Professor of Astronomy at
Dublin, where he made many excellent observations, especially those on Nutation and Aberration. Brinkley ought to have
been mentioned in Art. (30) of this Dissertation, as having contributed materially to the progress of the study of the Continental
Mathematics in the United Kingdom.
(312.)
James
Watt.
(313.)
Relation
of engi¬
neering to
physics.
(314.)
State of
mechanics
in the
seven¬
teenth cen'
tury.
Chap. IV.. $ 1.1 MECHANICS.—WATT. 865
considerable proper motion of an otherwise un-
conspicuous star, first reduced Galileo’s theory to
successful practice. The details of this elaborate in¬
vestigation have been considered by competent judges
as among the happiest specimens of astronomical in¬
duction ; and like Professor Henderson’s, they have
also had the advantage of subsequent and still more
independent corroboration. Professor Johnson of
Oxford, using, like Bessel, a divided object-glass
micrometer (or heliometer, as it is not very appro¬
priately called, never being applied to the sun), has
obtained results for the parallax of a Cygni almost
identical with Bessel’s, which was O’35 of a second.
I am sorry that my limits will not allow me to
explain more particularly the details of Bessel’s
method,‘which, however, may be found in several
modern works on astronomy.
M. Peters of the Observatory of Pulkowa has an¬
nounced several additional parallaxes, all determined
with the aid of a meridian instrument. He has even
attempted to infer the mean parallax of stars of the
1st, 2d, &c. magnitudes, which M. Struve has com¬
pared with his estimate of relative distance derived
from other considerations ; but the numbers of as¬
certained parallaxes, as well as their amount, ai'e too
small, and the anomalies still too apparent (as in
the case of the star No. 1830 of Groombridge’s
Catalogue), and the parallactic distances too often
inverted on the scale of brightness, to allow us to
attach much importance to these generalizations.
CHAPTER IV.
MECHANICS OF SOLID AND FLUID BODIES, CIVIL ENGINEERING, AND ACOUSTICS.
§ 1. Watt.—Condition of Practical Mechanics previous to the time of Watt. His genius for the
application of Science to Practice. His successive Improvements on the Steam-Engine. Steam
Navigation.
James Watt may be considered as the most dis¬
tinguished 'practical man of science of the last cen¬
tury, or even for a much longer period. But this is
not all. Few men achieve such a reputation as his
without having done more than originate a great in¬
vention for the use and benefit of mankind in all ages :
—He also taught men to raise the useful arts to a new
dignity,—to marry them to genuine, unpretending,
and inductive science,—to disparage ignorance and
empiricism, and to render the labours of the work¬
shop subservient to intellectual progress.
I have attempted, in the first chapter of this Dis¬
sertation, to place the scientific part of engineering in
its due relation to pure physics, and I have compared
the relation between them to that subsisting between
Mathematics and Physics—the one as an instrument,
the other as an end. Now it was this, in particular,
which made Watt the important character he really
was. He brought out the dependence of the former sub¬
jects, as Newton and others had successfully taught
and demonstrated that of the latter.
To appreciate Watt’s merit, we must compare the
purely mechanical contrivances of the period preced¬
ing the date of his improvements on the steam-engine
wdth those of a similar space of time succeeding it.
In the former we find multitudes of contrivances on
paper—ingenious, indeed, but many of which could
not be executed; the greater part of the remainder
could not be carried into effect through want of know¬
ledge in the inventor. We have large promises of
VOL. i.
“ semi-omnipotent engines,” perpetual motions,
“ quintessences of motion,” and the like, mingled
with trivial mechanical toys ; or we have elaborate
diagrams of mill-gearing, lathes, fountains, and saw¬
ing machines without end, illustrated with showy and
expensive plates, but destitute, for the most part, of
the slightest novelty of principle, or truly mechani¬
cal skill in application. Here and there, no doubt,
elegant and appropriate contrivances for communi¬
cating or sustaining motion occur; but nearly all
the best forms of elementary machinery were of re¬
mote antiquity, excepting those connected with clock¬
work, which, including the great and truly scientific
application of the principle of Isochronism, formed
the only considerable step in philosophical mechanics
for very many years previous to the conception of
the steam-engine. The statical part of mechanics
had made more progress. Masonry and Carpentry
had attained a degree of perfection in many respects
admirable, under the Italian and Norman architects ;
but the really difficult theory of machinery in motion
was little understood before Watt’s day, and the
knowledge which then existed was unassociated with
practical skill or commercial enterprize. It could
be found only in profound treatises of theoretical
mechanics, and in experimental courses of natural
philosophy. The sources of power were almost ex¬
clusively those derived from simple gravity and the
impact of fluids. It was not, indeed, the good for¬
tune of Watt to be the first to employ the admirable
5 R
(311.)
. Petera.
866
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(315.)
Philosophi¬
cal spirit
infused in¬
to practical
mechanics
by Watt.
Estimate
of Watt’s
genius.
(316.)
properties of steam as a source of power; but be was
almost the first to study them as a philosopher, and
to apply, with exemplary patience and skill, princi¬
ples sought in the laboratory, to make available the
most convenient of all motive forces. This was done
by means of a series of contrivances so ingenious—
so strictly connected by scientific relations—as to he
a model of experimental research, quite as much as
a triumph of mechanical art.
Such combinations of theory and practice have now
become far from rare. They have followed the march
of physical learning, they have borrowed from it,
and they have contributed to it. But it was Watt
who chiefly gave the happy example. Himself by
education and habit strictly a mechanic, he had the
peculiar merit of apprehending the value of theory,
and of acquiring a kind of knowledge then altogether
uncommon amongst persons of his profession. He
was no doubt a successful speculator, and a shrewd
ingenious man besides; and this, his ostensible cha¬
racter, constituted possibly in the eyes of many his
world-wide celebrity. But such considerations were
little likely to influence the opinions of contemporary
scientific men well qualified to judge, and least of all
of eminent foreigners, who generallyregard with little
partiality the presumed commercial character of their
insular neighbours. Dr Black, who was by no means
prodigal of praise, termed the steam-engine, as im¬
proved by Watt, “ an invention which is in its pre¬
sent state the master-piece of human skill,” not
“ the production of a chance observation, but the
result of deep thought and reflection, and really a
present by philosophy to the arts.’’1 Professor Bo-
bison, who knewr Mr Watt intimately, was even more
enthusiastic in his appreciation of his genius; and
Sir Humphry Davy, in a speech manifesting a just
estimate of his peculiar merits, did not hesitate to
place him on a level with Archimedes.2 But a tes¬
timony more authoritative and unbiassed than any
of these, is the fact that Watt was elected first a
corresponding member of the French Institute, and
finally one of the eight foreign Associates of the Aca¬
demy of Sciences. This honour, to which so few can
attain, which Newton once owned, and which now7
graces or lately graced the names of Y^oung, Hum¬
boldt, Oersted, Brewster, and Robert Brown, is a
sure passport to scientific immortality. Here, at
least, no utilitarian pride, nor even the laudably pa¬
triotic emotion of gratitude to one w7ho had proved,
in more w ays than one, his country’s benefactor, can
be supposed to have influenced in the remotest de¬
gree his election.
Having said thus much on the position to which
Watt’s inventions entitle him in the narrative of the
history of science, we may refer wdth brevity to the
generally well-known improvements of the steam-
engine, in which they mainly consist. In Sir John
Leslie’s Dissertation, a space of but a few lines has
been devoted to them, which seems inadequate to
their importance. For details, however, we must
refer to the articles in the Encyclopaedia where they
are explained at full length.
No doubt we cannot in strictness call Watt the f3.17-)
inventor of the steam-engine. The grand principle
of rendering the heat contained in steam available as engine,
an economical source of moving power may be traced
so far back that we lose the clue altogether in the
obscure, or impracticable, or simply puerile shapes
in w hich the idea was contained. Even in the time
of Worcester (1663) we must be allowed to doubt
whether the history of the steam-engine had out¬
grown the mythical stage ; Papin, indeed, proposed
a piston and cylinder in which the vacuum was pro¬
duced by steam instead of by the air-pump (as already
suggested or practised by Guericke) ; but Savery
(16 98) was the first who constructed a steam-engine,
and applied it to the drainage of mines. His inven¬
tion included the two capital properties of steam, its
power of producing a vacuum by condensation, and
its elastic force at high temperatures. A few years
later the piston-foi'm was introduced or re-invented
by Newcomen and Cawley, as well as the valuable
expedient of producing condensation by a squirt of
cold w7ater injected into the cylinder; and in this
condition the Atmospheric Engine remained w'ith
slight improvement for above half a century, doing
the work for which it was invented,—the pumping
of water out of shafts (the pump being moved by a
chain attached to the end of a horizontal oscillating
beam),—wherever economy of fuel was unimportant.
Such was the case at coal pits, but in other mines,
usually situated remote from coal, it was of compara¬
tively little use, on account of the enormous con¬
sumption of fuel.
James Watt was born at Greenock in 1736, and, (318.)
owing to feeble health, seems to have enjoyed little
advantage from regular tuition of any kind ; which hig.
was, however, to a great extent made up for by the tory,
intelligent spirit with which he acquired knowledge
without assistance on a great variety of subjects. At
the age of nineteen he proceeded to London, w'here
he learned mathematical-instrument making, but he
soon returned to Scotland, intending to pursue that
business in Glasgow. Here he met with obstacles,
but finally, by the patronage of Dr Adam Smith, Dr
Black, and other professors, he was established as
instrument-maker to the university within the college
buildings. I mention these details because they show
that Watt, as early at least as 1757, had been favour¬
ably noticed by the most celebrated professors then
in Glasgow, and had received a special pledge of their
good will.3 It is evident that the professors of Che-
1 Lectures, i., 181. 2 Speech at Freemasons’ Hall, preserved in Arago’s Eloge of Watt, and in Davy’s Works, vol. vii.
3 It appears from Mr Muirhead’s work on The Origin and Progress of the Mechanical Inventions of James Watt (published since
the greater part of the text of this section was written), that Watt’s introduction to the college took place “through the instru-
Chap. IV., § 1.]
MECHANICS.—WATT.
867
andconnec-mistry and Natural Philosophy (Dr Black and Dr
D^Black ^c^)’ obtained for him his appointment,
must have been also his chief academical employers;
and we may safely conclude that Watt constructed
much of Dr Black’s apparatus, as he was certainly
admitted to intimate and confidential intercourse with
that great and amiable man. Dr Black removed to
Edinburgh in 1766, but the friendship which he had
extended to the young mechanic remained unaltered
during their joint lives, although their personal in¬
tercourse must have been extremely slight after that
time. Now Watt’s first thought of improving the
steam-engine dates (as we shall see) from the session
1763-4, the last hut one of Black’s stay in Glasgow ;
their intimacy was therefore fully established by that
time ; and we find Watt acknowledging his “ obliga¬
tions to him for the information received from his
conversation, and particularly for the knowledge of
the doctrine of latent heat;”1 and we also find that
during Watt's experiments on steam subsequent to
the last-mentioned date, Black was cognizant of them,
and assisted in their contrivance.2 Moreover, Watt
admits Dr Cullen’s well-known experiment of redu¬
cing the temperature of ebullition under the air-pump
to have been one of his starting points in the im¬
provement of the steam-engine.3 Yet this experiment
was not 'published until 1770,4 and Watt must have
heard of it from Black himself, or from some one
attending his lectures, whei’e the fact was almost cer¬
tainly mentioned. Whether formally & student of Dr
Black’s chemistry class or not, it is therefore evident
that Watt enjoyed advantages in the prosecution of
experimental physics which nineteen-twentieths of
enrolled students never attain. He had the privilege
of unreserved personal intercourse, amounting at last
to intimate friendship, with the first authority of the
last century on the subject of Heat, and one of the
most cautious and accomplished of inductive philo¬
sophers.5 Watt’s eminent merits, and doubtless his
merits alone, gained him this happy position ; but
had he remained either at Greenock, or with the op¬
tician in Cornhill, he might have failed to combine
so admirably as he did the character of the practical
man and the philosopher. His place in science was His posi-
well typified by his position in Glasgow. His wastion in
“ the workshop within the College.” Whilst the la-coile8^
boratories of the classes of Chemistry and Natui'al ^
Philosophy must have been his familiar resort, his
own rooms were frequented by the most intelligent
students, including his contemporary Dr Bobison,
where subjects of science particularly connected with
mechanics -were diligently canvassed. The extent of
his knowledge and the variety of his resources were
fully tested, and the result, as stated by the generous
pen of Bobison, was a conviction of the superiority of
Watt in these respects to any of his contemporaries.
It is a fact worthy of note that the immediate oc- (319.)
casion of Watt’s improvements was the commercial Watt’s first
consideration of economy. In 1763 or 1764, being
called on to repair a model of the Atmospheric En-Steam.
gine in the Natural Philosophy class at Glasgow
(which model is still preserved), he found the amount
of steam expended in heating the cylinder at each
stroke to be so great that the boiler was insufficient
to supply it properly. He then commenced experi¬
ments on the amount of steam thus consumed, and on
the means of diminishing it. Though the primary ob¬
ject was the repair of a model, it is not to be doubted
that Mr M att had in view the practical improvement
of the engine on the great scale, with the use of which
in the coal-fields of the west of Scotland he was pro¬
bably familiar, having the intention of becoming
himself a civil engineer, and being already acquainted
with the writings of Desaguiliers and Belidor.6
mentality of his mother’s kinsman Mr George Muirhead, who had then (1754) just exchanged the professorship of oriental lan¬
guages for that of Latin.” It will be seen that this refers to a period antecedent to his journey to London.
1 Letter to Dr Brewster in Robison’s Mechanical Philosophy, ii., p. v.
2 Robison’s Mechanical Philosophy, ii., 115, note (by Mr Watt).
3 Ibid., p. vii., and 114, note.
4 In the Edinburgh Physical and Literary Essays, vol. ii., Dr Black (who was intimate with Cullen) knew of it at least in
1757. Lectures, i., 525.
5 It is perhaps unfortunate that Mr Watt, when on the verge of fourscore, contrary to his ovn intentions, but yielding to “ the
representation of friends,” recorded a complaint that his best friends, Black and Robison, had refused him his due share of merit
in the improvement of the steam-engine, and disclaimed, as injurious, the appellation of “ a pupil of Dr Black” (letter to Dr
Brewster in Robison’s Mechanical Philosophy, vol. ii., p. v.) Admitting (as he does on the same page) that the doctrine of latent
heat was due to Dr Black, and that he first learnt it from him, he adds, “ this theory did not lead to the improvements I after¬
wards made in the engine,” p. viii. No one ever ascribed to Black the beautiful invention of a separate condenser, but even
Watt’s most ardent eulogists (Lord Brougham and M. Arago) admit that the theory of latent heat “ forms the key to the econo¬
mical appreciation of the steam-engine.” So far was Watt from being independent of Dr Black’s assistance in this matter, that
* he himself tells us twice over, in substantially the same language, that when in the course of his experiments on the model engine
in Glasgow College in 1764 he was “ at a loss to understand how much cold water could be heated by so small a quantity in the
form of steam,” he “applied to Ur Black, and then first understood what was called latent heat'’ (Robison, ii., p. v.; also p. 116,
note). Mr Watt might have been the discoverer of latent heat, and the solver of his own dilemma, had not Dr Black been at
hand. It is the highest compliment wre can pay him to say that such an achievement was not too much to expect from him.
[These conclusions are fully substantiated by the interesting documents lately published by Mr Muirhead in the Correspondence
of Watt on the Composition of Water, p. 6, and in his Mechanical Inventions of James Watt, vol. i., p. Ixxxi.; vol. ii. pp. 116, 118,
119, 275. In the last-cited passage Watt himself fixes the date and manner of his receiving from Dr Black his knowledge of the
doctrine of Latent Heat. He says, “ I myself never attended his (Dr Black’s) lectures; but the doctor explained his doctrines
to me about the year 1763.”] Note added during printing.
6 See Mr Watt’s own narrative in Robison’s Mechanical Philosophy, ii,, 113, note; and in Mr Muirhead’s Mechanical Inventions
of James Watt, vol. i.
868
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(320.) When Watt discovered by means of his model that
Imperfec- condensation and loss of steam in the cylinder at
mospheric every stroke of the piston exceeded that which is use-
engine. fully employed in producing the vacuum, he proceed¬
ed very methodically to ascertain the chief numerical
data or constants upon 'which the working of steam-
engines depend ; as, the hulk of steam of given elas¬
ticity compared with that of the water producing it, the
elasticities of steam at different temperatures, espe¬
cially above the boiling point, the evaporating power
of a pound of coals, and finally, the expenditure of
steam and of injection-water for a single stroke. The
last, the amount of cold water required effectually to
condense the cylinderful of steam, appeared so very
large that it at once betrayed the source of the waste¬
ful expenditure of fuel. All the heat which was ab¬
stracted by the injection-water had to be supplied
afresh at a vast expense of steam, and consequently
of coal, before a fresh stroke could he made. The
mere amount of steam necessary to fill the cylinder
and elevate the piston was a trifle in comparison. He
naturally ascribed it to the absorption of heat by the
material of the cylinder, which no doubt was an im¬
portant element; and he tried cylinders of different
materials, and ascertained (in most instances for the
first time) the specific heats of the substances used.
But still the amount of injection-water remained un¬
accounted for, and the regulation of it was the great
difficulty of the old engine. If a tolerable vacuum
was desired, the cylinder must he flooded with cold
water, and all the heat abstracted must he restored
before the next stroke was produced. If, on the other
hand, the injection was imperfect, so that the con¬
densed steam and water together retained a high
temperature, an atmosphere of vapour so elastic
spoiled the vacuum, and in many cases the working
efficiency of the engine was reduced to about half of
the atmospheric pressure.
(321.) The theory of latent heat, showing that steam con-
Watt’s tains as much heat as if the water yielding it had
principle peen raise(i through 1000° of temperature, gave a
condensa- clear explanation of the enormous amount of injec¬
tion. tion-water necessary. How to escape from the diffi¬
culty was another question, which was solved solely
by Mr Watt, who, early in 1765, first conceived the
idea of retaining the cylinder always at the boiling
heat, and effecting condensation in a separate vessel
kept constantly as cold as possible, in which injection
should also take place, and into which the steam of
the cylinder would spontaneously rush, on a commu¬
nication being opened at the proper instant. The suc¬
cess of this device was complete, and it was speedily
followed by a series of admirable and mutually de¬
pendent improvements which Watt introduced. To .
keep the cylinder as warm as possible, it was first
provided with a cover, through which the piston-rod
passed by means of a stuffing-box. Then steam it¬
self was employed to press down the piston, instead
of atmospheric air which cooled the cylinder injuri¬
ously.
Having thus steam on each side of the piston, the (322.)
step was easy to make the engine a double-acting
one; so that the volume of steam which by its elas- ing enSine-
ticity impelled the piston during its descent, being
thrown into the condenser, produced the vacuum
necessary to make the ascending stroke equally ad¬
vantageous.1 But in pumping-engines, which had
hitherto been the main employment of steam, or fire
engines (as they were then called), it was sufficient
that the power was produced in one direction, that
is, to lift the pump-rods ;2 but the double action of a
pushing and pulling force was evidently applicable
to every sort of machinery by the use of a crank and
fly-wheel. A difficulty, however, was experienced in
applying this push-and-pull movement to the oscil¬
lating beam which had so long formed a part of the
atmospheric engine, and which it was so convenient to
use. Mr Watt obviated it with his customary saga- Parallel
city, and succeeded in inventing a connection of rigid motion,
jointed links which effectually united the piston-rod
with the end of the beam, the former moving in a
vertical straight line, the latter in a circular arc, so
that pressure was transmitted in the manner of either
push or pull without the slightest practical incon¬
venience. No doubt the locus of the motion of the
piston-rod head is not rigorously straight. It is, when
fully developed, a curve of the fourth order, resem¬
bling a very elongated figure 8 ; but the portion of
the curve in use is practically straight. This happy
solution, the most elegant perhaps in the science of
pure machinery, or kinematics, was not the result of
a formal mathematical research, but presented itself
to the mind of Watt, as he tells us, almost intui¬
tively. It became from henceforth an important ele¬
ment of mechanical combinations.
Other methods of producing direct rotation oc- (323.)
curred to the ingenious mind of Watt, and many of Expansive
them were shown to be practicable by being actually workmS-
executed in model size. But the next great practi¬
cal improvement introduced by him was the princi-
ciple of expansive working, whereby a saving of steam
is produced (particularly in single-acting engines),
second in importance only to the result of the sepa¬
rate condensation. This consists in allowing the
steam to flow in upon the piston during only the first
part of the stroke ; the rest being completed partly
1 This happy idea seems to have been suggested by Dr Small of Birmingham in a letter to Watt, of date 5th November 1769.
“ I see no reason why you should not condense at both ends of your cylinder, and drive all before you, back stroke and
fore stroke.”—Mechanical Inventions of James Watt, i. p. 81. The uncommon sagacity of Dr Small, and the important services
which he rendered in many ways to Watt, come out clearly for the first time in this work.
2 So associated were these engines with the operation of raising water, that we find they were at one time used to supply
common water-wheels with a constant stream, and thus to produce continued motion for mill-work, &c.
Chap. IV., § 1.]
MECHANICS.—WATT.
369
by the inertia of the moving machinery, hnt chiefly
by the continuous though constantly diminishing
elasticity of the steam as it expands and fills the en¬
tire cylinder.1 It is evident that, in the extreme case,
the work required (in pumping) will be accomplished
if the piston reach the end of the stroke just as its
momentum is exhausted, and that, on the other hand,
if the pressure of the steam remain constant through¬
out, the Velocity will be a maximum just when the
work being done by the machine is suddenly com¬
pleted, and so much moving power will be wasted.
A medium distribution produces the most favourable
result in practice, and it depends entirely upon the
ratio between the resistance and the effective pres¬
sure of the steam what this most favourable propor-
Cornish tion will be. In the single-pumping engines of Corn-
engines. wall, in which the economy of fuel is carried to the
highest perfection, it frequently happens that not
more than one-eighth of the stroke is performed un¬
der the full pressure of the steam, which acts expan¬
sively during the remainder of the stroke ; but these
engines, though condensing, are moved by steam of
four times the elasticity of the atmosphere. The
Cornish engines have been very elaborately perfected,
and they have been more carefully tested in respect
to performance than any others. It is perhaps not
too much to say that they do not contain a single
contrivance of any importance (beyond of course
what they have in common with the atmospheric
eno-ine), which was not the unaided invention of Mr
Watt.
(324.) In the Cornish engine we see the Energy of Heat
Their per- ren(jereq available to an extent which the inventor
fection. .. ,
himselt would at one time have thought scarcely cre¬
dible. The combustion of a bushel of coal which in
a Newcomen’s engine improved by Smeaton was
capable of raising 3,000,000 pounds through one
foot, in Watt’s improved pumping engine raised
20,000,000 pounds the same height. But by the
indefatigable skill and perseverance of engineers the
Cornish pumps now yield at least five times the last
amount. This, however, is not the place to enter
upon these details, nor can we stop to particularize
the other and various mechanical inventions intro¬
duced by Watt in the form of valves, governors, and
steam-indicators. Still less can we enlarge upon the
endless and still multiplying applications of this ad¬
mirable moving power, which is as capable of super¬
seding the greatest natural forces hitherto applied by
man to the useful arts, as it is adapted by its easy
regulation to replace human industry in the most
delicate operations; “ the trunk of an elephant,
which can pick up a pin or rend an oak, is as nothing
to it.”2
Of the applications of the steam-engine with which (325.)
Mr Watt was less immediately connected, its adap-
tation to locomotion in the case of ships in the last steam to
century, and in that of railway trains in the present, navigation,
have been the most striking, and fraught with con¬
sequences the most important to mankind. Of the
latter we shall have occasion to speak in a future
section ; of the origin of steam navigation we may
here say a very few words. Passing over projects
which never were realized, of moving barges by steam,
or other inanimate power, against wind and tide,—
such as those of Worcester, Papin, and Hulls,—wre
find that the first experiment entitled to be called
successful was made by Mr Miller of Dalswinton in Miller—
Scotland, conjointly -with Mr James Taylor, tutor in Taylor-
his family, who together formed the project of mov¬
ing vessels by means of paddle-wheels driven by a
steam-engine, and realized it with the aid of Sym¬
ington, a practical engineer. As we shall also find
in the case of steam-carriages, the idea of the applica¬
tion of the steam-engine to move ships was already
a familiar one to the minds of many persons about
the middle of the last century. To put it in practice
with advantage was the step required. Mr Miller’s
first boat was launched on Dalswinton Loch in Dum¬
friesshire, in October 1788, and attained a speed of
five miles an hour. The subject was pursued by
Symington and others. In 1789 a larger vessel was
propelled on the Forth and Clyde Canal. Subse¬
quently, however, the invention languished. The
want of co-operation, of capital, and ingenuity, na¬
turally extinguishes many valuable inventions. Watt
himself was only rescued from the same difficulty by
the unusual intelligence of Boulton and Small, his
coadjutors at Birmingham. Symington was less for¬
tunate, as well as probably less meritorious ; and
though it is well established that Fulton, who passes
on the other side of the Atlantic for the inventor of
steam-ships, had seen the relics of Symington’s second
experiment, we must do the Americans the justice to
say that the application of steam to navigation first
flourished in the United States. In 1807 Fulton Fulton,
started a river boat with an engine of Boulton and
Watt. In 1813 the example was tardily imitated on
the Firth of Clyde. The subsequent improvements
need not here be specified. They have been very
great and striking, but with the exception of the recent
substitution of the screw-propeller for paddle-wheels,
they scarcely involve any new principles.3
We may briefly close what we have to say of Mr (326.)
Watt personally. His health was feeble from child- ^ar°eter
hood, but being blessed with much calmness of tern- 0f Watt,
per he prolonged his life to a great age, and passed
through its struggles, though they were to him con-
1 The double-acting engine was planned in 1774 or 1775. The expansion principle was first used in 1776 ; the parallel motion
was patented in 1784.—Watt’s Notes on Dr Robison’s Article. Robison’s Mech. Phil., vol. ii. 2 Lord Jeffrey.
3 For farther details on the history of Steam Navigation, see that article in the Encyclopaedia; and Mr Rennet Woodcroft’s
work on the subject, London, 1848.
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
870
siderable, ■without serious injury. Vexatious law¬
suits connected with his valuable patent rights af¬
forded him but too much occupation and anxiety.
He wrote little, and he did not covet fame. He was
fond of chemistry as well as mechanics, and was well
acquainted with the theory and practice of that science
as it then existed. He put forth opinions on the
chemical constitution of water which, in the judg¬
ment of some, entitle him to contest priority in the
discovery with Cavendish. He must have been
versed in mathematics in his early years, as we learn
from his friend Dr Robison, but there is no evidence
that he ever attempted a strict theory of his own engine.
Nor were his successors in this respect more fortu¬
nate. The best practical writers on the steam-engine,
up even to a late period, gave most rude and inac¬
curate rules for computing its effects; and it is to a
Frenchman, M. de Pambour, that we owe the first
philosophical, and, at the same time, elementary
analysis of this noble machine.
(327.) Much light has been thrown upon the character of
Personal 'Watt by the recent publication of his correspondence
of Watt6,r by Mr Muirhead.1 We there see the pressure of phy-
continued. sical infirmity, and mental despondency and indif¬
ference, under which he laboured from boyhood. We
learn the accumulated difficulties, arising from the
backward state of the mechanical arts in his time,
which delayed for years the successful prosecution of
his happiest, and what would appear in our day
most easily realized, conceptions. We see him at
times ready to abandon fame and profit for the en¬
joyment of the humblest competence with tranquil¬
lity. We find him, mechanic though he was, shrink¬
ing from possible collision with the opinions or in¬
terests of others, and in his early as in his latest
days, solicitous to avoid responsibility. He had, in
a word, throughout, the finely strung susceptibility of
a man of genius, singularly at variance with the
necessity he was under of pushing his way in the
world, and of turning his inventions to the best com¬
mercial account. Providentially he was thrown in
the way of friends to whom, by his private character,
he was greatly endeai’ed, and who supplied the ele¬
ments necessary to the successful prosecution of his
schemes. The sanguine zeal of Roebuck, the com¬
mercial sagacity of the capitalist Boulton, and not
least, the sympathizing friendship of Dr Small, who
was well fitted by his character and attainments to
mediate between Watt and the other two, were all
essential to the realization of the improved steam-
engine.
When Mr Watt was finally relieved of the oppres- (328.)
sion and chicaneries of his opponents in the courts Close of bis
of law, he was settling down into a peaceful old age.llfe-
He probably hoped to live over again some of the
scientific passages of his youth in sympathy with his
second son, Gregory, who possessed a decided taste
for science, but was unfortunately early cut off. Re¬
spected and beloved by a large group of friends, many
of whom survived him, and admired by a far wider
circle, he died at Heathfield, near Birmingham, 25th
August 1819. Statesmen, philosophers, and men
of the world, united in extolling the worth of his
character and the greatness of his genius.
§ 2. Robison.—Application of Statical Principles to Engineering—especially to Practical
Masonry. Coulomb.—Friction—Force of Torsion.
(329.)
Robison a
practical
philoso¬
pher.
The name of Robison may perhaps not appear to
be sufficiently identified with any great discovery to
merit a place in this condensed sketch of the pro¬
gress of science biographically illustrated. Were
there no other claim, I should consider it a sufficient
one to entitle him to at least a brief notice, that he
was by far the -most important, and, as M. Arago
has justly called him, “ most illustrious contributor”
to the earlier editions of the Encyclopcedia Britan-
nica. But he was also a philosopher in a high
sense of the word. His knowledge was multifarious
in no ordinary degree. He had little of pretension
to originality, yet he brought to bear upon matters
of science an unfailing amount of excellent common
sense, and his personal acquaintance with the Arts
which may be called Philosophical far exceeded, I
imagine, that of any man of his time. Though not
without his prepossessions, he was generous in the
highest degree in his estimation of others, who in
some sense might have been considered his rivals ;
he wras eminently patient in his study of the wmrks
of his contemporaries, and in his published writings
he laboured to render the results generally accessi¬
ble to ordinary readers, by means of laborious ab¬
stracts, intermingled often with highly original views;
and he explained them wdth conscientious energy
in his lectures to the students of Natural Philo¬
sophy, whom for thirty years of his life it was his
pride and pleasure to instruct. Amidst these con¬
genial labours he found little time for making pro¬
longed original trains of experiment, though the spe¬
cimens which he has almost incidentally left us give
the fullest proof of his ability in this respect; and
the explanation is, I have no doubt, to be found in
the peculiar circumstances of his early life. Until
his settlement in Edinburgh, he passed his time in a
series of active pursuits, having much more of the
character of stirring practical life than of literary re-
1 The Origin and Progress of the Mechanical Inventions of James Watt. 3 vols. 1855.
Chap. IV., § 2.]
MECHANICS.—ROBISON.
871
pose or scientific contemplation. He was tliirty-five
years old when he began to lecture in Edinburgh;
and though an excellent working age, it is rai’e indeed
to find that the talent of discovering new truths has
been formed and developed so late in life. A major
part of the great steps in science have been taken at
even a much earlier period.
(330.) That Robison possessed all the elements of an
nen/ser" or^nal thinker we shall presently endeavour to
vices as an show; hut had his excellences consisted alone in
expositor those we have specified, he would have been a per-
of science, son eminently useful in forwarding the march of
science. In fact, a few more such authors in every
generation would be cheaply purchased by the post¬
ponement of some second-rate discoveries. Men—and
we include men of science—are in too great a hurry
to push on (actuated often by a morbid love of praise)
to acquire something they may call their own, whilst
they are little acquainted with the important contri¬
butions of their rivals in the race of fame, and of the
predecessors to whom they really owe so much of
what they may choose to consider their peculiar
property. To methodize knowledge from time to time
—to present discoveries in a form different from that
in which they were first published, and thus con¬
nect them with what is already known and what re¬
mains to be clearly proved—these are real services
to science which contribute in a very essential
manner to its progress. Robison was a teacher, not
only to the youth of his native country, but to the
men of science and of practice of all countries, and
of many succeeding years.
HU TV *I°HN Robison was born in 1739, entered the Uni¬
life and'V versity Glasgow at the early age of eleven, and gra-
friendship duated at seventeen. His early tastes were directed
with Watt, towards Natural Philosophy. He studied Mathema¬
tics (as in after life) chiefly with reference to its appli-
) cations. Whilst at Glasgow he formed the intimate
acquaintance of James Watt, then a practical instru¬
ment maker. In a passage of a private paper, pub¬
lished first in Arago’s Eloge of Watt,1 Robison, with
his characteristic generosity, describes his mortifica¬
tion when “ yet a young student” at finding him
much his superior in mathematical and mechanical
knowledge ; but M. Arago has omitted to state that
Watt was, at least, three years the senior, which at
such an age, and on such subjects, might make all
the difference between a beginner and a proficient.
But the truth is, that with a rarely generous rivalry
in excellence, each esteemed the other most; for we
find Watt bearing a similar testimony to the supe¬
riority of his friend and junior : 111 was happy to
find in him [Robison] a person who was so much
better informed on mathematical and philosophical
subjects than I was.”2 It was by Robison that
Watt had his attention first directed to the steam-
engine ; their correspondence appears to have been
frequent during their joint lives ; and near the close
of his life Watt acknowledged “ his obligations to
him for very much information and occasional assist¬
ance in his pursuits ;” and in the Edinburgh professor
he found not only the zealous defender before a court
of law of Ins rights as an inventor, but also the first
who expounded methodically the principles and de¬
tails of the steam-engine in a manner which, at least
until lately, had not been superseded.
In 1758 he left Glasgow, and the following year (332.)
he went to sea as tutor to a son of Admiral Knowles. dven*
His life in a man-of-war, during which he saw some
active service in Canada, Avas favourable to the de¬
velopment of his practical turn of mind, and doubt¬
less gave him an interest in seamanship, naval archi¬
tecture, and other subjects, which he afterwards
turned to good account; and a subsequent expedi¬
tion to Jamaica, for the trial of Harrison’s Time¬
keeper, exercised him in some of the practical parts
of astronomy. He returned, however, to Glasgow
in 1761, and attached himself with such success
to the study of Chemistry under Dr Black that he
taught the Chemical Class in the university for seve¬
ral sessions.3 But his active life was not at an end.
In 1770 he accompanied his first patron, Admiral
Knowles, to Russia, and for some years \Aras em¬
ployed, first as his secretary, superintending im¬
provements in the marine establishment, and after¬
wards as professor of Mathematics in the naval
school of Cronstadt. He spoke and wrote the
Russian language with facility,4 and performed his
duties to the satisfaction of all. But in 1774 he and his ap-
could not resist the honourable invitation which he I,ointment
received to fill the chair of Natural Philosophy in of
the University of Edinburgh, where he spent the Edin-
remainder of his life, Avhich terminated in January burgh*
1805, amidst incessant literary occupation, even
when repeated attacks of a painful disorder had pre¬
vented him from personally continuing his lectures.
This brief sketch5 of a career rather unusual for (333.)
a man of science throws light upon Robison’s pecu- Character
liar merits. He had extensive, and then uncommon, of ,llls.ar‘,
P tides in the
opportunities ot acquiring information, of seeing van- Encudo-
ous countries, and of noticing their physical peculiar!- pcedia Bri-
ties; of being introduced to their society and literature;tannica'
1 And since, in extenxo, in MuirheacVs Mechanical Inventions of James Watt, vol. i., p. xli.
2 Ibid., vol. ii., p. 293.
3 The MS. of these lectures, written with curious care, but with the use of continual abbreviations of the larger words for
the sake of compression, is now in my possession, having been given to me by his son, the late Sir John Robison. I have also
many others of his MSS., which for the most part seem to have been printed in some form or other. Dr Robison was an indefa¬
tigable penman, and wrote and re-wrote his lectures with great labour. He also made elaborate analyses of his reading, but the
bad habit of contracting words remained with him through life.
4 The private marks on his MSS. are often in the Russian character.
° A much fuller one will be found in Playfair’s Works, vol. iv.
372 MATHEMATICAL AND PHYSICAL SCIENCE. [Diss. VI.
of takino- part in the actual execution of scientific who might have been called upon for a scientific
designs ; of studying foreign languages ; and of opinion (of far more weight than what generally goes
methodizing his knowledge for the purposes of in- by the name) on almost any practical subject upon
struction. Every one of these influences may he which he might have been consulted ; and that not
clearly traced in his writings, which will challenge merely in its general outlines, but in its strictest de¬
comparison with those of any English writer, except tails ; not only the design for a roof or a centre,
perhaps Dr Thomas Young, for variety and fulness but the scantling of the timber to be used; the mi-
of information, and for the general soundness and nutise of a pump or hot-air stove ; the curvatures of
strongly practical character of the mechanical know- an achromatic object-glass ; the temperament of a
ledo-e& with which they abound. They would also piano; or the angle for the pallets of an escapement,
doubtless have appeared to far greater advantage had In such matters nothing important either in the
they been the product of his most vigorous days ; but theory or the practice of his times escaped him. His
he was little known as a writer until the year 1793, opinions were very generally formed on original con-
when he commenced a series of important contribu- siderations, supported by experiments equally well
tions to the Encyclopcedia Britannica, embracing devised and carried out. His method of finding
at least forty-six articles, all scientific, some of great mechanically the relation between the intrados and
length and elaboration, which were published during extrados of a properly balanced arch by means of
the succeeding eight years, a period when he was seri- suspended pieces of chain is as ingenious as it is
ously afflicted with chronic disease. They embraced elementary ; but his observations on the manner in
disquisitions on general philosophy, as in the articles which stone arches, when overloaded, break up, es-
Philosophy and Physics; of strict science, as in tablished on direct observation and experiment, un-
Astronomy, Dynamics, Projectiles, Pneumatics ; of questionably gave a just foundation to the theory
the more experimental sciences, as in Magnetism, of masonry, till then so generally and erroneously
Electricity, Sound; of the art of music (with which treated of by mathematicians with the preposterous
he was practically conversant), in Temperament, abstraction of the forces of friction and cohesion,
Piano, &c.; but his great strength lay in the ar- the action of which in many instances vastly exceeds
tides in which just mechanical principles were ap- the direct effect of gravity.
plied successfully, and often with marked originality, But on this we must not dwell. Robison’s articles (335.)
to practice, as in Arch, Roof, Carpentry, and Strength on Electricity and Magnetism are deserving of nearly
of Materials; Resistance, Rivers, and Waterworks ; equal praise with reference to the state of knowledge and
Seamanship, Steam and Steam-Engine ; Machinery, of the time. Probably there was not one author of magnetism.
Telescope, and Watchwork. merit on these subjects, whatever his country or lan-
(334.) The last-named articles (most of which have been guage, whose works he had not laboriously consulted
His Me- collected in a compilation, edited by Sir David and analysed the conclusions; whilst a multitude of
chanical Brewster, in four thick volumes, entitled Robi- ingenious experiments give evidence of the skill and
Philosophy. ? Mechanical Philosophy) constitute a body patience of the writer. To Dr Robison we are, indeed,
of knowledge in civil engineering which has not indebted for the approximate knowledge of the pri¬
vet been surpassed in clear exposition of physi- mary law of electric attractions and repulsions ; for
cal principles and their application—in the ex- a careful consideration of those beautiful curves
tensive acquaintance it shows with the details of formed by iron filings round magnets,1 to which such
practice—and in proofs of elaborate and impar- an enlarged importance has since been given by the
tial study of authors, both British and foreign, on beautiful generalizations of Mr Faraday; and I be-
the subjects of which it treats. Several of these lieve likewise for the first suggestion of combining
articles have been resorted to by the most accom- the voltaic elements in a pile or column.2 Dr Robi-
plished engineers of our own time as stores of sound son, though for many years secretary of the Royal
experience, and they have been lavishly borrowed from Society of Edinburgh, published little in its Transac-
by some writers on similar subjects, occasionally with- tions, and almost nothing, so far as I am aware, in
out acknowledgment. The original matter which any periodical work. Hence his admirable adapta-
they contain is not always easily separated from that tions of experiments were little known beyond his
which is compiled. In every instance Dr Robison own class and friendly circle.
lays claim to less than his own share, and is so Of his more abstract mathematical writings we (336.)
scrupulous in quoting the names of other authors, need say little. He was thoroughly acquainted with
that he has unquestionably received less reputation the works and methods of Newton, and with nearly 5ng and
from these Essays than he deserves. He writes like all those of the same school, particularly of Bos- mathe-
Sound a man w^° has himself used the saw and hammer, covich. He laboured incessantly to reduce the de- matical ac-
practical who has had the responsibility of success or failure, monstrations of the higher mechanics and astrono- ^Qt3m
views.    ——       7
1 Indirectly we owe to him also the first exact determination of the mathematical properties of these curves, made at his
request by Mr Playfair.—Robison’s Mech. Phil., iv. 350.
2 See the Fifth Dissertation (by Sir John Leslie), p. 739.
Chap IV., § 2.]
MECHANICS.—ROBISON—COULOMB.
873
my to their simplest and most geometrical elements.
But the result (as might have been foreseen) was in
many cases a wearisome prolixity; and originality
could not be expected in these departments without
applying the continental improvements in analysis :
not that Dr Robison overlooked these; hut he took
little pleasure in them ; and as regards Physical As¬
tronomy he adhered to the older methods. Having
been so long at St Petersburg, the writings of Euler
must have been familiar to him, as indeed they evi¬
dently were as far as regards all subjects connected
with mechanics: he justly, however, considered Euler
as a superficial natural philosopher, though an in¬
comparable mathematician.
(337.) As a lecturer in his own department, Robison was
^lecturer 8 ^ most eminent of his time, at least in Britain. That
his courses were not considered 'popular will easily he
understood from a slight inspection of his writings.
The demonstrations were long and copious, but too
rapidly delivered. “The singular felicity of his
own apprehension,” says Mr Playfair, “ made him
judge too favourably of the same power in others.”
The lectures must have abounded in practical details,
which ordinary students rarely appreciate ; and they
were deficient in experiments, which unquestionably
arose from no want of the ingenuity necessary either
to invent or execute them. On the other hand, the
effect of his discourses was greatly enhanced by
his striking and energetic delivery, and by the stores
of his memory, which often recalled the incidents of
the stirring life in which he had once been engaged ;
and to the more thoughtful and philosophic they
were rendered at once attractive and elevating in no
ordinary degree by the strain of fervent thought by
which they were accompanied, and the impress which
they frequently bore of the pure morality and ex¬
alted piety of their author.1
(338.) Apart from his local usefulness as a professor, we
His philo- regarci p)r Robison’s place in science as eminent
character, chiefly on account of the sagacity with which he ap¬
plied knowledge to practice, and analysed complicated
effects of force as manifested in engineering con¬
structions. This he did so ably as to guide future
practice, and to reflect much light on the theory of
solids more or less elastic and tenacious, and subject
to the intricate strains which gravity produces. The
difficulty and merit of these investigations will best
he gathered from the slow progress of his successors
in the same field. The criticism with which his
writings abound on the theories of even his more
celebrated contemporaries and predecessors show re¬
markable acuteness, patience, and independence of
thought. We may perhaps sometimes think him pre¬
judiced, hut his decisions are never uttered without an
elaborate statement of reasons, nor ever sullied by the
suggestions of jealousy or self-conceit. Had he been
an accomplished analyst he must have been less dis¬
tinguished in the equally important walk in which
he stood pre-eminent. The limits of human life and
faculties prevents universal attainment, but he was
surely no mean philosopher of whom the sexage¬
narian James Watt could say, “He was a man of
the clearest head and the most science of anybody I
have known” 2
Amongst the contemporaries of Robison was one (339.)
whose acquirements were in many respects very si- C°'^°™|>on
milar to his own, and who contributed, in a degree passive
second to no other philosopher of his day, to pro- strength,
mote sound views in the very same branches of
science. Charles-Augustin Coulomb (born 1736,
died 1806) was, like Robison, addicted through life
to practical enquiries, and was intimately acquainted
with all the details of the civil engineering of his
day. To him we owe a correct knowledge of the
laws of friction in most ordinary cases, and the right
application of them to the theory of machines, and
to that of the stability of structures. In a very re¬
markable paper, published in 1776, he analysed, from
the basis both of theory and experiment, the manner
in which columns of masonry give way under longi¬
tudinal pressure ; not, as had previously been sup¬
posed, by flexure under the imposed weight, like a
steel spring or a rod of deal, but by the sliding of
one portion of the column over another, at an angle
determined by the cohesion of the stone, and capable
of being reduced to a problem of maxima and mi¬
nima. This important principle is now known to
apply to wrought and cast iron, and many other sub¬
stances.
One of Coulomb’s happiest investigations was on (340.)
the force of torsion, or the resistance of wires to torsion¬
twisting ; which he showed to vary directly with the
angle of torsion, inversely as the length of the wire,
and directly as the square of its section. These me¬
chanical principles he applied with address to deter¬
mine the viscosity of fluids, and with still more con¬
summate skill and success to the measurement of
electrical and magnetical forces by the construction
of a Torsion Balance, similar in principle but ante¬
rior to that employed by Michel 1 and Cavendish for
estimating the force of gravity.
Coulomb’s researches on electricity (which have (341.)
been only partially published) will he made the sub- His re’
ject of discussion in another chapter of this Disser- resembled
tation ; they were the most sustained and elaborate Robison’s,
of his investigations, and display very considerable
mathematical resources. In this respect he had a
superiority over Robison, who, as we have seen, cul-
1 See Dr Chalmers’ Life, vol. i. That great man had a peculiar veneration for Dr Robison, and is understood to have received
impressions from attending his lectures which materially influenced his future life.
a Mechanical Inventions of James Watt, ii., p. 290.
VOL. I. 5 s
874
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
tivated precisely the same branches of science which
gave distinction to the career of Coulomb. When we
compare the two philosophers, we find that the former
was the more discursive reasoner and experimenter,
and was diverted, perhaps by the copiousness of his
erudition, and the attention with which he studied
the works of others, from doing full justice to his
own original powers. The latter excelled as a ma¬
thematician ; he concentrated his efforts more me¬
thodically, and displayed the results to the world (so
far as they were published) in a more consecutive
and lucid form. In uprightness of character and
high morality, the two philosophers bore a marked
resemblance. They were both sufferers from bad
health, and they died within about a year of each
other, at nearly the same age.
§ 3. Thomas Young—Strength of Materials, and Art of Construction (continued).—Telford
—Introduction of Iron into permanent Structures. Suspension Bridges.—Tredgold; Mr
Hodgkinson ; M. Navier.—Mr Robert Stephenson—Tubular Bridges.
(342.) It is a circumstance not uninstructive as to the
Difficulty progress and achievements of science, that the
^c*™Por'greatest modern philosopher who preceded Newton
the enquiry—Galileo—and one of the most eminent, if not
into the ' the most eminent, of his successors—Young—should
mechanical haye laboured with minute and practical care, and
of solids.68 with corresponding success, on a subject apparently
so humble and mechanical as the Strength of Mate¬
rials, and the Resistance of Beams to fracture.
Newton himself condescended to swing pendulums,
and to observe the collisions of elastic worsted balls.
It is sufficient here to advert to the exceeding inte¬
rest of enquiries which throw so much light upon
the internal constitution of bodies, and in some
instances intimately connect them with the laws of
vibration of elastic media, to which so much of
Modern Physics is intimately allied.
(343.) The eighteenth century was in this, as in so many
Progress other departments of science, sluggish and mechani-
d.unng tie cal, or else abstract and ultra-geometrical. The
century, learned labours ot Euler and the Bernotulhs on
elastic curves, and the strength of pillars, were for
the most part elegant mathematical amusements,
and with the exception of the experiments of Mus-
schenbroek in the earlier half of the century, and the
skilful but more limited researches of Coulomb at
its close, little valuable in the way of precise theory or
of accurate data derived from practice had been added
to this important branch of mechanical engineering.
(344.) Robison, indeed, with the peculiar tact and skill
Thomas which I have already ascribed to him, wrote several
Young. papers (contributed to an early edition of the Ency¬
clopedia Britannica, and printed in his collected
works) full of acute observation and reasoning,
adapted to the imperfect experiments of his time,
and connected by sound scientific deductions, which
are still well worthy of careful perusal; but it was
to the penetration of Dr Thomas Young,1 who par¬
took strongly of Robison’s mechanical tastes, whilst
he surpassed him in facility of mathematical resource,
that we owe a great revision of the doctrine of the
strength of materials. In the “ Syllabus of Lec¬
tures” (1802), into which he condensed, in a manner
peculiar to himself, an incredible amount of positive
knowledge ; in the Lectures themselves (1806), with
the admirable “ Catalogue of References and in
the articles on “ Bridges,” and the supplementary
propositions on “ Carpentry,” which he contributed
to this Encyclopaedia—we find (stated, as usual,
not without some obscurity) a multitude of theorems
and problems embracing the whole principles of
construction, and based upon mechanical laws and
the most probable interpretation of experiments.
The forces tending to alter the figure or dimensions (345.)
of substances usually called solid may be thus clas-
sified: (1.) Extending forces, or such as produce force to
elongation in a body when applied in a direct man- solids.—
ner. (2.) Compressive forces. (3.) Force produ-ExtenS10n•
cing detrusion, or the slipping of one portion of the
substance over another. (4.) Force producing flexure.
(5.) Torsion or twisting force. The resistance of bo¬
dies to extension was examined by Hooke and Grave-
sande, and is held to be directly as the area of section
of the body, and to increase directly as the amount of
elongation produced, at least within certain limits.
The measure of this resistance Young termed (not
very happily) Modulus of Elasticity, expressing the Modulus o)
force required to produce unit of elongation (or to Elasticity.
double the length) of a prism of the substance un¬
der experiment. This quantity may be measured
either by the length of a depending prism of the
substance which would produce the requisite strain,
or more simply by the strain expressed in pounds
or tons, which, supposing the elongations to increase
without limit as the extending forces, would double
the length of the prism under experiment. Thus,
in round numbers, a bar of wrought iron an inch
square will be extended xok^o Pai't hy a pressure
of one ton—hence the modulus of elasticity is about
10,000 tons. The elasticity of wrought iron remains
perfect to about half the breaking weight, after which
the elongations appear to double for each addition
of about y1^ or of the breaking weight. Thus, in
a recent experiment by Mr Edwin Clark, a bar of
1 I reserve to the chapter on Optics a fuller account of Young and his writings.
(346.)
Compress¬
ing force.
Detrusion.
(347.)
Flexure of
beams.
Chap. IV., § 3.1 MECHANICS.—YOUNG—TELFORD.
875
wrought iron, one inch square and ten feet long, ex¬
tended ^ its length for every ton of weight
up to 12 tons, from which point the extensions nearly
doubled successively for every two tons of load, and
the bar was finally torn asunder by 23 tons.
The compression of bodies proceeds (like the ex¬
tension) at first uniformly with the load. Some bo¬
dies resist compression more than extension (as cast
iron); some the reverse (as wrought iron). Sub¬
stances give way under compression after different
fashions. Hard bodies divide into prisms parallel to
the compressing force ; slender elastic bodies bend
laterally; soft bodies bulge horizontally; bodies of
a medium hardness divide into wedges, and the sur¬
faces slide along the plane of spontaneous fissure.
Detrusion marks more particularly the mode of giv¬
ing way by the sliding of surfaces in the interior of
solids. Though seldom due to force directly applied,
it is an important element in most cases of the rup¬
ture of semiductile solids.
The force of jiexure is that by which the resist¬
ance of the greater number of solids is most easily
overcome, but which it is of most importance to re¬
sist ; as when a beam is fastened by one end into a
wall, and loaded at the other, or when it spans a
horizontal space. It had not escaped the notice of
James Bernouilli, Duhamel, and other writers of the
earlier part of the 17 th century, that the fibres on
the concave side of a loaded beam are in a state of
compression and not of extension, and that there is
therefore a point, or rather a line, in every beam, in
which the fibres are neither extended nor compressed.
But the clear modification of the theory prevalent
in the time of Leibnitz and Marriotte which this
consideration introduced, was probably first deve¬
loped by Coulomb, Robison, and Young, who in their
respective publications insisted upon it with great
judgment; and it is difficult to overrate its import¬
ance in mechanical engineering, although the first
great canon of Galileo remains still true, that the
ultimate strength of a solid rectangular beam varies
as the breadth and as the square of the depth.
The writings of Young and Robison did not im¬
mediately attract the attention of practical men,
and Coulomb, who was by far the ablest French
experimenter on subjects of mixed mechanics,
seems to have done less on the theory of strains
producing flexure than in the case of torsion, which
he studied with so much success, and applied to
such excellent purpose. Nevertheless in his memoir
on the Resistance of Masonry, in the 7th vol. of the
“ Memoires Presentes” (1776), he had already laid
down very clearly the effect of compression on abeam.1 2
It is, however, to Young that we owe the application
of these principles in unfolding their legitimate conse¬
quences. In a series of remarkable propositions con¬
tained in the writings I have quoted (344), he assigns
numerical relations between the flexure of a beam
under almost every supposable circumstance, and
the resistance of the material to direct strains. These
results have been extensively used by all subsequent
writers. They are not equally verified in all classes of
substances. This, however, is not wonderful; flexure
is not due to direct compressive and extending strains
alone ; deformation may take place in a solid without
appreciable change of density, thus giving rise to
some of the nicest questions in molecular physics.
The laws of Torsion, as laid down by Coulomb, (348.)
have been mentioned in the last section (340). Torsion.
The mathematical investigations of Young on (349.)
mechanical problems were conducted with bold di- Young's
rectness and in defiance of the generalizing methods
and symmetrical notation of foreign writers on such
subjects. But his pre-eminent sagacity in laying hold
on the salient points of the questions he discussed,
and in conducting his argument to a practical con¬
clusion, was unequalled, and deserves imitation.3
A great revival in the study of the properties of (350.)
elastic matter, as regards strength, took place about General
the year 1820, probably in consequence of the in-^®^
troduction of wrought iron into the construction ofiron>
suspension bridges, which has been attended with
important results.
Thomas Telford, though neither the contriver of (351.)
suspension bridges, nor the introducer of them into Telford;
Britain,3 deserves notice from the superior boldness ^idges10n
and solidity of the noblest work of the kind which
has yet been executed—the Menai Bridge. Telford
(and the same may be said of his contemporary
Rennie) was more distinguished as a man of judg¬
ment, integrity, and experience, than as eminently
original or philosophical. In this respect both yield
to Smeaton, who, with Watt, was the founder (each
in his own department) of modern engineering. But
the beautiful and truly workmanlike structure of the
Menai Bridge inaugurated the era of the extensive
introduction of that admirable material, wrought
iron, into great permanent structures exposed to
heavy strains. Cast iron had been used much ear¬
lier, as in the bridge erected at Colebrookdale in
1777 by Mr Derby, and in the very beautiful arch
at Sunderland, which dates from 1796. The span
of the Menai Bridge is 580 feet, the whole quantity
of iron used was 2186 tons, the transverse section
of the suspending chains or bars was 260 square
inches, supporting a strain of 1094^ tons. This
1 Reprinted in the Theorie des Machines Simples, Paris, 1821.
2 A copious selection from Young’s mechanical writings may be found in his Miscell. Works edited by Dr Peacock, vol. n.
3 Captain Samuel Brown erected the first considerable chain bridge in this country across the Tweed in 1819.
876
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
was a work quite unexampled at the time of its
erection (1826), and showed a sagacious confidence
in the employment of a material then comparatively
little trusted.
(352) Telford never made extensive experiments on the
Ziata of re-resistance of solids. Some special ones were indeed
sistance. made under his direction on wrought iron in par¬
ticular, but in general he seems to have relied upon
the old ones of Musschenbroek and Buffon. The
barlow,andtw0 persons who first in recent times vigorously
Hodgkin- applied themselves to the practical determination
8on- of the data of resistance so long deficient, were Tred-
gold, a private engineer, and Professor Barlow of
Woolwich. The data they obtained have since been
generally used, not only in this, hut in other coun¬
tries. Tredgold’s works (on Carpentry, Strength of
Timber, &c.) show a very great aptitude in applying
the results of science to practice, and an acquaintance
with both which is rarely attained. Mr Eaton Hodg-
kinson has made many valuable additions to Tred¬
gold’s work, and has contributed an excellent paper
on the strength of pillars to the Philosophical Trans¬
actions (1840.)
^353^ To Mr Hodgkinson we are also indebted for a
Geometry useful investigation (in the Manchester Transac-
of the tions) into the figure assumed by the chains of sus-
catenary. pension bridges. The elegant properties of the
simple or geometrical catenary were fully investi¬
gated a century and a half since by the Bernouillis
and by David Gregory, hut the application of sus¬
pended structures of immense weight to purposes of
utility suggested new problems. Amongst these,
perhaps the most interesting was the catenary of
uniform strength, in which the section of the sus¬
pending chains is made everywhere proportional to
the strain which they have to resist at that particu¬
lar point. Its equation was investigated by Mr Da¬
vies Gilbert in 1826. An elegant and valuable con¬
tribution to the geometry of catenarian curves was
made by the late Professor Wallace of Edinburgh,1
with particular application to curves of equilibration
for bridges of masonry after the ingenious manner
of Bobison mentioned in Art. (334).
(354.) connection with suspension bridges, and also
M. Navier. with researches on the yielding of elastic materials,
we must record the name of M. Navier, a very
eminent French engineer and writer on practical
and theoretical mechanics. His work on suspension
bridges (1823) is one of the earliest and best. He
is also well known for his physico-mathematical re¬
searches on the yielding of elastic solids to pressure
under given circumstances, in the course of which he
came into collision with Poisson, who gave a some¬
what different theory. The subject is one of ex¬
treme difficulty, owing to our ignorance of the
molecular constitution of bodies; and it is believed
that all these investigations were so far erroneous
that they were based upon the assumption of a single
constant to represent the resistance of bodies to
change of form and dimension. These (form and
dimension) are two very different things, and require
distinct treatment.2 British mathematicians have
lately paid much attention to these enquiries, with
the prospect of a solid improvement in engineering
theories.3
The art of bridging over great spaces has been (355.)
pushed, by the requirements of the railway system, to Mr Robert
an astonishing extent, and under circumstances of^pllen'
peculiar difficulty. I shall connect these improve¬
ments with the name of Mr Robert Stephenson,
the inventor of the Tubular Bridge, a work which,
in its very simplicity, is a triumph of art, and being
nothing more than a hollow beam of somewhat pecu¬
liar construction, supported at the ends, it is an ad¬
mirable instance of a structure of which the stability
may he easily reduced to calculation.
The wooden bridges of Switzerland were for a long (356.)
time unequalled as skilful works of carpentry. During j^jgeTin
the last century the Rhine at Schaff hausen was crossed Switzer-
by two spans of 171 and 193 feet. At Trenton, inland and
America, the river Delaware is crossed by a wooden Araerica«
bridge, of which one arch is 200 feet in span. It is
on the bow principle, an elastic wooden arch, convex
upwards, being skilfully braced and united to a level
roadway passing through the spring of the arches.
The American lattice bridge, very simply and skil¬
fully contrived, has great firmness, owing to the depth
of the framing, and exercises no hoi’izontal thrust on
the piers. The widest spanned wooden bridge in the
world, 340 feet, across the Schuylkill, at Philadel¬
phia, designed by Wernwag, combines the how and
lattice principle.
In these we might see foreshadowed in some faint (357.)
degree the principle of the Tubular Bridge, the The tubular
greatest discovery in construction of our day. But bridSe-
in reality the idea of it arose from a different con¬
sideration.
During the first ten or fifteen years of railway ex- (358.)
perience, engineers had gradually acquired a correct
perception of the manner in which cast and wrought bridges,
iron may most effectually and economically be formed
1 Edinburgh Transactions, vol. xiv.
3 About twenty years ago, the present writer showed that India rubber, which possesses to such a remarkable extent the
quality which may be termed cubical flexibility, is yet scarcely at all compressible—in fact, just as much as water, and no more.
Though not otherwise published, he has been in the habit of demonstrating this in his annual course of lectures.
3 Professor Stokes in Cambridge Transactions, vol. viii.; Mr Clerk Maxwell in Edinburgh Transactions, vol. xx. Mr M.
Rankine in Cambridge and Dublin Math. Journal for 1851 and 1852. Experimental data are still deficient; but M. Wertheim
has lately published some valuable ones (which are still in progress) in the Annales de Chimie.
Chap. IV., § 3.]
MECHANICS.—MR STEPHENSON.
877
into girders or beams supported at the ends, and
adapted for sustaining enormous loads. Such beams
were constructed, often of single castings, so as to in¬
clude three portions ; an upper flange, alower/cm^e,
and a web, or thinner vertical plate connecting the two.
The relative section of the upper and lower flange was
made to vary with the material. In cast iron, which
yields far more easily to tensile than to compressive
strains, the lower flange should be almost incom¬
parably greater than the upper; in wrought iron a
slight predominance should be given to the upper
flange for the converse reason.
(359.) Hence it will be easily understood how, when Mr
6tubular ^'0^)er^ Stephenson was desired to construct a rail-
bridgUe de-r way bridge across the Menai Strait,—subject to the
rived from onerous condition imposed by the Admiralty, that it
them. should (even at the abutments) be without lateral
struts or diagonal pieces below the roadway,—he
should have entertained the idea of a gigantic girder
with a top and bottom flange of proportionate extent,
with a deep web uniting them, or rather of two such
girders placed side by side, thus forming square
tubes, of which the lower flanges should constitute
the bottom, the upper flanges the top, and the two
webs the sides.
(360.) It is not for me in this place to explain how, step
Progress of by step, the idea of a tubular bridge of wrought iron
tion!nVen" assumed the practical shape, now to be seen at Con¬
way, and near Bangor, in North Wales. It is un¬
fortunately notorious that there has existed an un¬
happy rivalry as to the share of merit due to the
several persons who of necessity were jointly con¬
cerned in the completion even of the design of these
astonishing works. Unfortunately for Mr Stephen¬
son’s tranquillity, the tremendous responsibility of
this novel, gigantic, and costly experiment, was
thrown upon him during the very height of the com¬
mercial and engineering excitement (not unjustly
called mania) which prevailed in 1845 and 1846, on
the subject of railway projects. Instead of the un¬
interrupted leisure which he required to superintend
his preliminary experiments, to consider his plans,
and perform his calculations, Mr Stephenson, as well
as every other engineer of eminence was at that time
engaged all day and a great part of the night in the
unparalleled worry of Parliamentary contests. As a
matter of course, much was trusted to able, confi¬
dential, and highly paid assistants. The experiments
on models of different forms, which alone cost many
thousand pounds, could not all be conducted in the
presence of the chief engineer. Yet he alone was
responsible for the failure or success of the plan.
(361.) The comparatively great strength of tubes was
lartoT11*1" a known from the time of Galileo. Their de¬
fect was a liability to crumple or pucker. Round,
oval, and rectangular tubes were tried, and the last
(Mr Stephenson’s original conception) were, as might
be supposed, found to be stronger than the other
two. When supported at the ends, and loaded in
the middle, model tubes of this form invariably gave
way at the top. How to strengthen the top against
compressive strains was the question. The exces¬
sive stiffness of corrugated iron and zinc plates (long
previously used for roofs) came to the engineer’s
assistance. A combination of two longitudinally cor¬
rugated or goffered wrought-iron plates running
along the top of the model, and forming long and
nearly cylindrical cells, was found to give the re¬
quired stiffness with the least increase of weight.
Ultimately a square arrangement of cells was adopted,
principally to give facility for painting and repair.
The tubes were hindered from racking by means of
numerous wrought-iron frames employed to stiffen
them, whose section resembled the letter T, and which
were called T irons. Suitable diaphragms were also
inserted at short distances along the tubes. The
widest spaces to be spanned at the Menai Strait were Dimensions
460 feet, there being two intervals of this width, and and
two of 230 feet. The tubes are 30 feet high and 14 streng.th of
broad, containing a transverse section of about 1500 the bridge‘
square inches of wrought iron. The weight of one
principal tube is about 1450 tons, and its strength,
measured by the breaking load at the centre, above
2300 tons. This last number is calculated from the
experiments on the breaking weight of models, one
of which was on no less than a sixth of the true
scale. The boilerplates, of which the tubes are com¬
posed, are united by mechanical pressure by means
of hot rivets; and it may safely be affirmed that
without this ingenious and perfect method of com¬
bination (which is due to Mr Fairbairn), the struc¬
ture would have been impossible.
The success of this astonishing piece of engineer- (362.)
ing has been complete; the stiffness of the tubes,Its com-
whether under constant pressure or during the rapid plete suc’
transit of trains, is almost incredibly great.
To Mr Robert Stephenson is clearly due the credit (363.)
of undertaking, on his sole responsibility, a projectMr Ste-
of equal boldness and novelty, and of contriving, not Phensoilthe
perhaps in every detail, but m its totality, the means inventor;
by which so signal a triumph of art and of science was
carried into eftect, an honour to his own age, and a
lesson to posterity. To Mr Fairbairn and Mr Hodg- assisted by
kinson, his assistants, selected by himself, much praise ^e.ssrs.
is also due for the manner in which the experiments and^iodg-
were managed, and the principles established by these kinson.
educed. Mr Fairbairn, a practical engineer of Man¬
chester, well known for his experience and sagacity,
gave to Mr Stephenson, as a matter of honour, the
full benefit of both ; and his confidence in the result
helped no doubt to sustain the manly courage of his
principal amidst a storm of opposition. Mr Hodg-
kinson, well known for his able enquiries into the
strength of pillars and girders of different forms,
conducted the mathematical enquiries, and deter¬
mined the relative strengths of the models. His con¬
fidence in the result was less encouraging than that
of his coadjutor, which serves to show the greatness
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(364.)
Commis¬
sion on
railway
bridges.
(365.)
(366.)
Marc Isaim
bart Bru¬
nei.
(367.)
His early
history.
878
of the responsibility of the engineer-in-chief. As
neither Mr Fairbairn nor Mr Hodgkinson could have
incurred any just blame had the vast structure when
on the eve of completion doubled up under its own
weight, and blocked up, perhaps for ever, the navi¬
gation of half the Menai Strait, so neither can they
possibly claim more than a subordinate share in the
success of the undertaking.1
I shall here only refer to the work of Mr Edwin
Clark, the resident engineer of the Britannia Bridge,
for farther details of its principles and construction,
and to the report of a royal commission (published
in 1849) on the application of iron to railway struc¬
tures, for many curious researches connected with the
subject of this section. In particular, we find a theo¬
retical and practical solution of the very delicate pro¬
blem of the influence of the speed of passing loads on
the deflection of bridges, to which Professors Willis
and Stokes, and Colonel James, R.E., are contributors.
Mr Robert Stephenson is the son of Mr George
Stephenson, who will be mentioned in a succeeding
section. He was born in 1803; educated (in part) at Other
the University of Edinburgh, under Leslie, Hope, and
Jameson ; he long occupied the chief position in the phenson.
locomotive factory established by his father at New¬
castle, having in the first place constructed under
his direction the celebrated “ Rocket” engine which
gained the prize at the opening of the Liverpool
and Manchester railway. To his own exertions,
both before and after that period, the locomotive
owes much of its present perfection. He surveyed
and principally carried through the London and Bir¬
mingham railway, the second great line in the king¬
dom ; and he has been engaged in a large proportion
of the most remarkable engineering works connected
with railways, both in this country and abroad. He
has personally superintended the construction of
railways amidst the blowing sands of Egypt, and in
Norway with its heavy winter snows and deeply frozen
soil. His high personal character, both for skill and
integrity, has everywhere procured him the respect
and confidence of his profession and of the public.
4. Brunel.—Self-acting Machinery.—The Thames Tunnel.—Mr Babbage’s Calculating
Engines.
Sir Marc Isambart Brunei, born at Hacqueville
in Normandy on the 25th April 1769, was one of the
most inventive mechanicians and engineers of his day.
As his genius gave a strong impression to contem¬
porary art, we associate his name with the progress
of civil engineering in the earlier part of the pre¬
sent century, particularly in connection with me¬
chanism. Like most of his eminent coevals in the
same profession, he had not the benefit of a scien¬
tific education ; but he more than most of them sup¬
plied its defects by a singular capacity for correct
induction and by great mechanical ingenuity. Though
a native of France, it was in Great Britain that his
talents were to find their full scope, and it became his
thoroughly adopted country.
Disgusted by the horrors of the first revolution,
he quitted France in 1793 in the capacity of a com¬
mon sailor, a position far below that which either his
birth or his intellect entitled him to hold, yet in
which he made himself remarked by his excellent
disposition and mental superiority. His destination
was New York, where in 1794 he commenced his
career as a civil engineer, his boyish tastes having
already indicated this as his natural calling. He exe¬
cuted some considerable works, and planned many
more; it is stated that he there devised the essential
parts of his block machinery. About 1799 he decided
on settling in England.
It is probable that his talents and ingenuity alone
recommended him to a government employment at a Lg-
time when the mere fact of his being a Frenchman lish go-
must have acted as a powerful obstacle to his sue- vernment.
cess. Those who recollect the vivacity and bright
intelligence of even his later years, will understand
that in his more active days it must have been diffi¬
cult to refuse Brunei at least a hearing. And it is
to the credit of Lord Spencer, then one of the Lords
of the Admiralty, and of General Sir Samuel Ben-
tham, inspector of naval works, that Brunei was en¬
gaged in 1802 to superintend the erection of his cele¬
brated block machinery.
The invention of self-acting machinery to super- (369 )
sede the work of artisans was of course not new-Machinery.
The saw-mill and the spinning-jenny were already in
1 It has been alleged that Mr Stephenson’s original proposal to allow the suspension chains (which were primarily intended to
he used in putting together the tubes in their final positions) to remain in aid of the rigidity of the structure, manifested a
want of confidence in his own great idea. But a dispassionate consideration of his evidence before the committee of the
House of Commons would alone clearly show (independent of Mr Stephenson’s declarations on the subject) that he was
forced into the admission that the chains might give an ulterior guarantee against miscarriage of the whole plan, simply to save
the bill from being thrown out by the not unnatural incredulity of those to whom a proposal so new, so gigantic, and affecting the
lives of so many persons, as well as so great pecuniary and other interests, was for the first time and suddenly proposed. Be¬
sides this, even his own coadjutors did not all entirely support him. Mr Hodgkinson, whose character for scientific know¬
ledge carried great weight with the committee, recommended in his report the ultimate additional security of chains.
Chap. IV., § 4.]
MECHANICS.—BKUNEL—MR BABBAGE.
879
use, but the invention of Brunei was not less im¬
portant as creating an epoch in art. Not only is
it possible to execute in a comparatively short
time, and with a prodigious economy, objects such as
blocks and pulleys, which are required in vast num¬
bers and precisely alike, but the nicety and accuracy
of the manufacture is thereby increased, and owing
to the facility with which inanimate force may be
concentrated on machinery, works which transcend
the power of unaided muscular labour are as surely
and exactly executed as those of smaller dimensions.
For example, by no enlargement of the common
turning-lathe would it be possible to construct an
accurately turned iron steam-cylinder 8 feet or more
in diameter, which is yet readily executed under the
direction of a very ordinary workman by means of
steam power and self-acting machinery.
(370.) The block-machinery at Portsmouth consists of a
The block- series of engines impelled by steam, and by means of
machinery; which the materials of wood and metal employed in the
construction of ships’blocks are reduced to exact forms
in graduated sizes, and are finally put together with
very little manual labour. These machines, with the
exception of the turning-lathe and circular saw, were
wholly new, and, it is stated, were devised in part by
General Bentham, who gave to Brunei at least the
benefit of his advice and previous experiments. In
some of them we have the first germ of implements
now used by every machine-maker in the kingdom;
and the ingenuity of the movements, and the variety
of effects produced, earned for this great invention a
just celebrity. Such a beginning could not have
been made without the aid of government. To con¬
struct the tools was an expensive and troublesome
business, and to start the manufactory cost L.53,000,
which was speedily saved by the economy of the pro-
its results, cess. In the course of a year 140,000 blocks of no
less than 200 different patterns were produced, and
the number of workmen was diminished in the pro¬
portion of about 11 to 1. As a reward, Mr Brunei
received L.16,000, being two-thirds of the first year’s
saving, itself a sufficient proof that he was the bona
fide inventor of this admirable apparatus, whatever
hints he may have received from his immediate su-
(371.)
Gave an
impulse to
mechanics.
(372.)
Introduc-
tion of me¬
chanism
into work-
pen or.
So successful an experiment produced ultimately,
though with characteristic slowness, its effect on the
mercantile world ; nearly twenty years elapsed before
such a splendid example of ingenious economy and
artistic precision was at all generally imitated. Yet
before his death, Sir Marc Brunei saw the fruit of his
ingenuity almost indefinitely multiplied in the work¬
shops of London, Manchester, Glasgow, Newcastle,
and Birmingham, and highly appreciated if less ex¬
tensively imitated abroad.
The more we reflect on the comparative state of the
arts now and a century ago, the more we shall find
reason to estimate highly the introduction of correct
and scientific ideas of machinery and of tools for con¬
structing other machines and structures. It was, in
fact, the necessary complement of the invention of
the steam-engine. Watt contrived the mighty Heart
which was to give a new impulse to social life, Bru¬
nei and others of the same stamp added limbs and
muscles, whereby its energies were rendered tho¬
roughly practical. The sixteenth, seventeenth, and
part of the eighteenth centuries, had given to the
world designs for countless mechanical contrivances,
often highly original anti ingenious. But many
were grounded on fallacies, and others belong to
the class of elaborate trifles. At that period the
slide-rest of the turning-lathe, the planing machine,
and the circular saw, were practically unknown; at
least the two former, which are incomparably the
most important inventions of their class, and which
belong to no certain author, having almost imper¬
ceptibly come into use—the slide-rest about the Slide-rest
end of the last century, the planing machine as f1111 Plan'
lately as about 1820. The former of these readily ^?n™a'
forms surfaces of revolution with geometrical accu¬
racy, the latter plane surfaces, and in either case
the application to metals is most important. The
circular saw and slide-rest form part of Brunei’s
series of machines, and he afterwards constructed the
former on a very great scale for the manufacture of
wooden veneers. To them he added the mortising
machine, and these, it will be seen (together with the
planing engine), form the staple of the magnificent
and varied apparatus with which, driven by the gi¬
gantic power of steam, our mechanical factories are
now so generally provided. We again repeat that
the triumphs of art in which our generation glories,
our railroads, our locomotives, our crystal palaces,
and our steam navies, would have been impossible
feats but for the improvement of tools and the substi¬
tution of steam for muscular power.
Every one is, however, aware that Brunei owed his (373.)
reputation to other achievements as well as his im- TheThames
provements of mechanical tools. The Thames Tun-Tunne1,
nel will ever be considered as his most arduous tri¬
umph. It is a structure of exquisite firmness laid
in a quicksand. It will endure like the cloacee of
regal Rome, when the palace and the cathedral have
crumbled to dust. Yet here also we perceive that
it was Brunei’s exquisite mechanical tact and inge¬
nuity which enabled him to succeed. The problem
of the tunnel is not one of balancing vaults; the sta¬
tical conditions of stability are simple enough, and
it was not in the solution of such that Brunei pecu¬
liarly excelled. The practical problem was to intro¬
duce a rigid tube of brick horizontally into the
middle of a quaking mass of mud ; and the solution
was the invention of a tool which should enable men
to make the excavation and to proceed with the
building in safety. It was the shield which carried The shield.
the tunnel under the Thames,—a moveable veidical
frame of cast iron, provided with thirty-six cells, in
each of which a man was placed with a pick to ex-
880
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
cavate the area required for the construction of the
tunnel. By a simple but most ingenious contrivance,
every part of the face of unstable clay was firmly
supported by boards which leaned upon the frame or
shield, which, in its turn, pressed against the part of
the brickwork of the tunnel already completed. Each
workman could remove one or more of these small
boards at pleasure, and excavate a short way into
the yielding mass before him, then advance the boards
and sustain the slippery fdfce. When the whole face
had thus undergone piecemeal excavation, the frame
or shield was moved bodily forwards by powerful
screws, and the bricklayers brought up the masonry
behind, which was then beyond the reach of injury.
(374.) The idea of the shield was derived, it is stated, from
Completion a specimen in the arsenal at Chatham, showing the
of^the tun- 0pera^ons 0f a testaceous worm which bores under
water, and wdiich nature has provided with a protec¬
tive covering. But the analogy is certainly indirect,
since water could hardly retard the operations of
such an animal. Repeated irruptions of the Thames
several times drowned the work, which was as often
abandoned and renewed, but every difficulty was met
by fresh resources on the part of the engineer. The
failure of funds was a far more serious obstacle, and
government at last came to the aid of an undertak¬
ing of such consummate ingenuity that its comple¬
tion was deemed due to the honour of the nation.
The tunnel was commenced on the 2d March 1825,
Death of and finished 25th March 1843. Brunei survived the
Brunei. completion of his great work above six years, dying
on the 12th December 1849, aged 81.
(375.) We have not in this brief sketch glanced at one
Variety of jia|£ 0£ ingenious projects and successful enter-
ins works l o
prizes. Scarcely any branch of his multiform pro¬
fession but received some improvement at his hand.
The discovery of the condensation of several gases in
1823, by Mr Faraday, suggested to Brunei their ap¬
plication as a moving power; and his want of suc¬
cess did not arise from any deficiency on his part of
skill or forethought. He was one of the first to con¬
struct a roof of extreme lightness, somewhat resem¬
bling those now in use for railway stations. He
erected a suspension bridge in the Isle of Bourbon
on an original plan; and he pointed out with cha¬
racteristic shrewdness how much of the stability of
arches depends upon the cohesion of the parts, so
that the vault may in some cases be entirely dis¬
pensed with.
(376.) It will be understood that we have selected Sir
Marc Brunei as the representative of a class, the
eminently mechanical engineers, a class now exten¬
sively multiplied, and amongst whom his son, Mr
Brunei, occupies an eminent position.
(377.) It cannot be expected in an essay like the present
Calculat- that I should enter into the details of the variety of
chfneTof mechanical inventions which have now become so
Mr Bab- numerous, and which have been marked by every
bage.
gradation of originality and resource. But as illus¬
trating a class of contrivances altogether different
from those of Brunelj though like them tending to
produce a great influence on the improvement of the
mechanical arts, I will briefly refer to the Calcu¬
lating Machines of Mr Babbage, which have at dif¬
ferent times excited the interest of the public and of
scientific men.
Mr Babbage was a fellow student at Cambridge (378.)
with Sir John Herschel and Dean Peacock, and along The differ-
with them he contributed by his writings and per- enceen8uie-
sonal efforts to introduce into that university the
improved Continental mathematics. A few years after
leaving college he originated the plan of a machine
for calculating tables by means of successive orders
of differences, and having received for it in 1822 and
the following year the support of the Astronomical
and Royal Societies, and a grant of money from go¬
vernment, he proceeded to its execution. It is be¬
lieved that Mr Babbage was the first who thought
of employing mechanism for computing tables by
means of differences ; the machine was subsequently
termed the difference engine. In the course of his
proceedings Mr Babbage invented a mechanical no¬
tation (described in the Philosophical Transactions
for 1826), intended to showr the exact mutual rela¬
tions of all the parts of any connected machine, how¬
ever complex, at a given instant of time. He also
made himself acquainted with the various machines
used in the arts, with the tools used in constructing
them, and with the details of the most improved
workshops. Employing Mr Clements, a skilful me¬
chanist, a portion of the calculating machine, very
beautifully constructed, was brought into working
order, and its success so far answered the expecta¬
tions of its projector. But, notwithstanding several
additional grants from government, the outlay on
this most expensive kind of work soon exceeded them.
The part actually constructed is now placed in the
Museum of King’s College, London; it employs
numbers of nineteen digits, and effects summations
by means of three orders of differences. Though
only constituting a small part of the intended engine,
it involves the principles of the whole. The inventor
proposed to connect with it a printing apparatus, so
that the engine should not only tabulate the num¬
bers, but also print them beyond almost the possi¬
bility of error.
At this stage (1834) Mr Babbage contrived a ma- (379.)
chine of a far more comprehensive character, which The analy¬
se calls the Analytical Engine, extending the plan en‘
so as to develop algebraic quantities, and to tabu¬
late the numerical value of complicated functions
when one or more of the variables which they con¬
tain are made to alter their values. Had this engine
been constructed, it would necessarily have super¬
seded what had already been done. Government were
not unnaturally startled by this neAv proposal, and
as about the same time Mr Babbage’s relations to
Chap. IV., § 5.]
MECHANICS—TEEVITHICK G. STEPHENSON.
881
Mr Clements were broken off, the difficulties of the
affair became insurmountable, and the construction
of either engine has for some years been in abeyance.
The opinions of men of science are not unanimous
as to the great practical importance of calculating
tables by machinery, but the improvements of me¬
chanical contrivance which the joint skill of Mr
Babbage and Mr Clements introduced into engi¬
neering workshops are unquestionably of great impor¬
tance to the arts. Though the details of Mr Bab¬
bage’s plans have not been published, there can be
no doubt that, whether economical or not as sub¬
stitutions of machinery for human labour, they were
devised with remarkable skill and ingenuity, and even
on this account merit preservation.1
(380.) , Eecently (1855) attention has been directed in
calculating ^on<^on a s™P^e and effective Difference Engine
engine. constructed and patented by M. Scheutz, confessedly
on the principles of Mr Babbage, though without an
acquaintance with his mechanical contrivances. The
result is stated to be satisfactory. The engine deals
with fifteen digits or figures, and with four orders of
differences. Only eight figures are preserved in the
result, the others being reserved to prevent errors
arising from the accumulation of still lower digits
omitted. The engine not only computes with facility
and accuracy, but, by means of steel punches impress¬
ing lead, provides for the perpetuation of the num¬
bers in the form of stereotyped plates. The work¬
manship of the whole requires no particular nicety
of execution, is not liable to derangement, and can by
scarcely any contingency produce inaccurate results.
Before closing this section, we may advert to im- (381.)
provements in the theory of machines by those who Foreign
have regarded it rather from the geometrical side on
than from that of routine practice. Our French ofma-60^
neighbours have been distinguished in this respect, chines.
Carnot and He Prony, MM. Hachette, Poncelet, and
Morin, have been or are accomplished mechanists in
this respect; and in the French repertories we must
look for some of the earliest good scientific descrip¬
tions of machinery, even when of English invention.
In England, besides Mr Babbage, Professor Willis (382.)
of Cambridge has shown a peculiar aptitude in this ®nSlisl1
department, and has published a very valuable work authors‘
on machinery, regarded in a strictly geometrical sense.2
To Mr Moseley we are likewise indebted for some va¬
luable contributions to the theory of engineering.
(383.)
The loco¬
motive en¬
gine and
railway.
(384.)
Early anti¬
cipation
of steam-
carriages.
5. Trevithick.—George Stephenson-.—The Locomotive Steam-Engine.—Rise and Progress
of Railways.—M. de Pambour on Locomotives.
Of all the inventions which have powerfully af¬
fected the interests of mankind, none have been more
slowly perfected, or can be less certainly traced to a
single individual as the inventor, than those of the
Locomotive engine and the Kailway. These two great
and essentially connected portions of the greatest
mechanical and commercial effort of any age or
country had their origin in obscurity. Each ap¬
peared several times to be rising into the import¬
ance it deserved, but failing the concurrence of
the fortunate circumstances which are necessary to
give permanence to invention, was once more for¬
gotten and was left for re-discovery at a happier
epoch.
With regard to Steam-Carriages, passing over still
earlier speculations, we find that Dr John Kobison,
at the age of twenty-one, published a design for a
steam-carriage in the Universal Magazine for No¬
vember 1757, and that he also directed Mr Watt’s
attention to the steam-engine in the same year, with
a view to this very application. The cylinder of the
proposed machine was an inverted one, and Watt ac¬
tually made a rude model on Eobison’s suggestion.3
From this time the steam-carriage seems never to have
been long lost sight of by mechanical speculators.
It was included in a patent by one Moore, a linen
draper, in 176 9.4 In the same year it is stated that
Cugnot, a native of Lorraine, actually constructed
a steam-carriage, which, like the nearly contemporary
but unsuccessful efforts of his countrymen to effect
steam navigation, fell speedily into oblivion. About
1773 Edgeworth of Edgeworthstown urged the con¬
struction of steam-carriages, and at a later period ex¬
pressed, in terms of unequivocal anticipation, the
triumph arising from their connection with railways.
“ I have always thought,” he wrote in 1813, “that
steam would become the universal lord, and that we
should in time scorn post-horses. An iron railroad
would be a cheaper thing than a road on the com¬
mon construction.” At Soho the movement of car¬
riages as well as of boats by steam never was or could
be forgotten. In Watt’s patent of 1784 the steam- Watt and
carriage forms the seventh article, and in the sameMu^°c4h’
year5 Mr William Murdoch, a member of Boulton
and Watt’s establishment, made a model, acting by
high-pressure steam, which drove a small waggon
round the room. Hence it required no prophetic
power in Darwin, the intimate friend of Watt, to
1 For historical details connected with Mr Babbage’s engine, see Weld’s History of the Royal Society, vol. ii. An account of
the principles and action of the Difference Engine may he found in the Edinburgh Review for July 1834 : and those of the Ana-
lytical Engine in Taylor s Scientific Memoirs, vol. iii.
2 Principles of Mechanism. Camb., 1841. 3 Mechanical Inventions of James Watt, ii. 294.
* Mechanical Inventions of James Watt, i. 52. « Translation of Arago’s Eloge of Watt, p. 120, note.
VOh. I. 5 T
882 MATHEMATICAL AND
write those often quoted lines in the Botanic Garden
(canto i. line 290) :—
« Soon shall thine arm, unconquered Steam, afar
Drag the slow barge, or drive the rapid car.’
(385.) A somewhat longer pause now occurs. But in
Trevithick 1802 we find Richard Trevithick, a Cornish “ cap-
a?d Vi‘ . tain ” of a mine, taking out a patent along with Vi-
patenth^vian for the high-pressure steam-engine, and apply-
1802. ing it specifically and practically to the movement
of carnages or waggons along a railway at JMerthyr
Tydvil in South Wales. Mr Muirhead informs us
that Trevithick saw Murdoch’s model at Redruth in
Cornwall. But admitting this, it is plain that the
idea was much older still, and also that many years
elapsed without its ever being brought practically
to bear until the year 1804, when Trevithick’s loco¬
motive was actually used.
(386.) Richard Trevithick appears to have been one of
Account of the most ingenious men of his time ; but (from the
Trevithick. scanty notices which I have been able to collect1) to
have been also of an inconstant speculative disposi¬
tion, which prevented him from bringing any of his
numerous inventions to perfection. Yet he had the
good fortune, which so many inventors have missed,
of meeting with partners able and willing to assist him
in carrying out his designs. Amongst these was
Andrew Vivian, with whom in 1802 he took out the
patent already mentioned for the construction of high-
pressure engines, and their application to the move¬
ment of carriages along rails or common roads. As
Applies the first practical employer of high-pressure steam of
lure "steam ^ ^ Pressure on square inch, Trevithick
to locomo- deserves especial notice. He borrowed the notion of
tives on it, as well as the ingenious invention of the four-way
1804aySin coc^’ fr0111 an scheme of Leupold’s, but he over¬
came for the time the prejudice which had always
existed even in the mind of Watt against its adop¬
tion. His earliest engine is stated to have been con¬
nected with a common stage coach which ran on the
streets of London ; but his more successful and im¬
portant effort was made in dragging waggons along
the Merthyr Tydvil railway in South Wales, which
was successfully tried on the 21st February 1804,
when the engine drew carriages containing ten tons
of bar iron for a distance of nine miles at the rate of
five miles an hour. This was unquestionably the
first successful example of this modern species of
locomotion.
A f If look more closely at the means by which it
hisTengine was accomplisheclj we find still more reason to com¬
mend the sagacity of the inventor, and to wonder at
the interval of nearly thirty years which elapsed be¬
fore the general adoption of his plan. “A square
iron case containing the boiler and cylinder was placed
behind the large or hinder wheels of the carriage, and
was attached to a frame supported from the axles of
PHYSICAL SCIENCE. [Diss. VI.
those wheels. The cylinder was in a horizontal po¬
sition, and the piston-rod was projected backwards
and forwards in the line of the road towards the front
of the carriage. Across the square frame, supported
by the wheels of the carriage, an axle was extended
reaching a little beyond the frame on each side; this
axle was cranked in the middle, in a line with the
centre of the cylinder, and a connecting-rod passing
from the end of the piston turned this axle round,
and produced a continued rotatory motion of it when
the piston was moved backwards and forwards in the
cylinder; upon both ends of this axle cog-wheels
were fixed, which worked into similar cog-wheels
upon the axles of the wheels of the carriages, so that
when a rotatory motion was produced in the cranked
axle by the piston-rod it was communicated to the
axle of the larger or hinder wheels of the carriages,
and these wheels being fixed upon and turning round
with the axle, gave a progessive motion to the car¬
riage. Upon one end of the axle was fixed a fly¬
wheel to secure a rotatory motion in the axle at the
termination of each stroke.”2
We here find the cranked axle and the horizontal (388.)
cylinder of modern locomotives, both of which were
departed from by Trevithick himself, probably in
consequence of difficulties of execution. When we
add to this plain description, that the fly-wheel was
furnished with a break, that the boiler had a safety-
valve or a fusible plug beyond the reach of the engi¬
neer, and that the patent includes the production of
“ a more equable rotatory motion, .... by caus¬
ing the piston-rods of tvoo cylinders to work on the
said axis by means of cranks at a quarter of a turn
asunder,” it is scarcely too much to say that nothing
material was added to the design of the Locomotive
until the invention of the tubular boiler in 1829.
The Merthyr locomotive blew up, and the preju- (389.)
dice against high-pressure steam revived. The in- ^evi- ^
ventor, in the meantime, diverted his attention to gine ex_
other schemes, and continued his profession as apiodes.
Cornish mining engineer.
A singular circumstance opened for Trevithick a (390.)
new sphere. A Spanish-American gentleman named Hj^subse-
Uville, who was engaged in working the silver mines
of Peru, came to England in 1811, with a view to ,iisappoiiit-
discover an engine fit for draining those mines whose ment.
high elevation rendered condensing steam-engines
working under atmospheric pressure comparatively
inert. In London he met accidentally with a model
of Trevithick’s engine, and having carried it to the
heights of Pasco in Peru, and being satisfied with its
work, he did not rest until he had returned to Eng¬
land and transported nine high-pressure engines in
1814 to the scene of operations. In 1816 Trevi¬
thick himself followed, with coining engines and pu¬
rifying furnaces of his own contrivance. Had he
1 It is stated that the Society of Civil Engineers have in vain proposed a medal for a biography of Trevithick.
2 Wood on Railways. This description corresponds with Trevithick’s specification and drawings.—Repertory of Arts, &c., Se¬
cond Series, vol. iv.
Chap. IV., § 5.]
MECHANICS.—GEORGE STEPHENSON.
883
(391.)
(392.)
George Ste¬
phenson ;
His early
difficulties,
and charac¬
ter.
(393.)
He con¬
trives a
safety
lamp;
been a prudent man bis fortune was now made ; but
it is stated that after a year or two he returned to
this country impoverished and disappointed. I am
unacquainted with his further history.
In the meantime the locomotive engine, which
Trevithick had long abandoned to its fate, was be¬
coming known in the hands of a man perhaps of less
genius but of greater sagacity and perseverance.
George Stephenson, civil engineer, was born in
1780 near Newcastle, of respectable persons in the
humblest rank of life. His father was either a com¬
mon pitman or otherwise employed about the collier¬
ies of the district, and young Stephenson, without
any advantages of education, began to labour for his
bread at an early age. His work appears to have
been always connected with the machinery of the pits
above ground, and not with their excavation. Thus
he rose gradually to be an engine-man at the wages
of twelve shillings a week. This was at Killingworth
near Newcastle, where he showed considerable me¬
chanical ingenuity, and gradually gained the confi¬
dence of his employers. Having married in 1802,
he had a son born the following year, the present
Mr Robert Stephenson, M.P., whom he brought up
with the tenderest care, and whom he ever and justly
regarded with a father’s pride. In order to bestow
upon him the advantage of that education of which
he had himself felt the want, it is stated that he made
money at extra hours by mending his neighbours’
clocks and watches, and finally, in more prosperous
days, sent his son to complete his education at the
University of Edinburgh. George Stephenson never
acquired much book-learning himself, but by natural
sagacity and observation he attained to a sound
knowledge of mechanical principles. We do not
claim for him, however, the character of great inven¬
tiveness. His skill rather lay in perceiving how far
methods and contrivances already known might be
pushed to an advantageous result. He possessed
that shrewd decision which ingenious persons often
want, enabling him to detect what is truly valuable
in the numerous mechanical schemes which at any
time are afloat, and to devise the means of realizing
them. He also possessed that confidence in his own
judgment which is necessary to carry out principles
to their legitimate extent, but from which feebler or
less practical minds usually shrink.
Not to interrupt the principal topic of this section,
I will here only mention that in 1815 he set about
inventing a safety lamp for mines at a time when the
recent heavy loss of life in his own neighbourhood
had excited general attention; insomuch that Sir H.
Davy had been specially invited, by a meeting of per¬
sons interested, to propose a remedy. I shall in an¬
other place speak of the result; but in the meantime
I may state, that George Stephenson made some expe¬
riments of his own, which, leading him in the same
track which Davy followed, that of admitting the foul
air to the lamp through long narrow tubes, might in
the end have led him to a construction analogous
to that of the safety lamp. As matters stood, it
is not surprising that his efforts, though highly me¬
ritorious, led him slowly and uncertainly towards
the goal which Davy, having once sighted, arrived at
with that rapid instinct in which he has never been
surpassed. Stephenson was left behind, but was
rewarded by a handsome gift offered by his local
admirers, who, in doing so, naturally rather consi¬
dered the difficulties overcome by their humble
neighbour than the strictly comparative merit of the
two inventions.
But it is of the locomotive and of the railway that (394.)
we have here to speak.
The former, we have seen, had been brought to (395.)
considerable perfection by Trevithick. An engine on studies the
his plan had been constructed and used by Mr Blackett engine^0
of Wylam in Northumberland, near the place where
Stephenson resided, and was the basis of his im¬
provements. Blackett’s engine had two cylinders, an
addition often ascribed to Stephenson, but which, as
we have said, was included in Trevithick’s patent.
What he saw of the performance of this machine ap¬
pears to have convinced Stephenson, once for all, of
the groundlessness of an opinion which then and for
long after haunted the minds of railway engineers.
This opinion was, that the adhesion between the
wheels of a locomotive engine and the smooth iron
surfaces of the rails must be insufficient to allow the
impulsion of the train, at least with any degree of
velocity, or up the smallest inclination. Trevithick dismisses
had a scheme for increasing the adhesion, and this the fear of
ideal improvement was the subject of repeated pa- ^°s^®ci®nt
tents, some of a singular nature, between 1802 and the rails
1824, one of which, Blenkinsop’s, provided a cog¬
wheel in the engine working into a rack on the rail,
which was actually in use down at least to 1830. It
is rather a singular thing that men spurning theories,
as was the fashion of the engineers of that day, and
especially those of Smeaton’s school, should have
thought as little of an appeal to experiment on so
simple a matter as did the followers of Aristotle in
the seventeenth century, when Galileo offered to con¬
vince them that light and heavy bodies fall equally
fast. Forgetting that direct friction is always large,
and that it varies in proportion to the pressure, these
practical men could not get over their first impres¬
sion, that iron must slide on iron long before a heavy
train could be set in motion. It was characteristic
of Stephenson’s decision of character, that he dis¬
missed all doubts on the subject so soon as his obser¬
vations seemed distinct, and that he did not hesitate
to carry out his belief to its consequences, and to
maintain his confidence in the locomotive engine
against all antagonists.
I shall not stop to particularize Stephenson’s first (396.)
improvements on the locomotive, which were rather G-Steplmii-
in detail than in principle. He saw clearly all along p° QVSe!.m
that if it was to work at high speeds he must in every ments.
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
884
(398.)
Origin of
railways.
possible way diminish the vibrations and strains to
which it was subject, and which would otherwise ra¬
pidly wear out the machinery. For this purpose he
proposed to connect the engine with its carriage by
means of steam acting on six pistons in lieu of springs.
But perhaps his most material improvement con¬
sisted in the very simple one of throwing the waste
The steam-high-pressure steam as a blast into the chimney,
blast. which was found to increase enormously the force of
the fire, and the evaporating power of the boiler.
Engines having this improvement, and with two ver¬
tical cylinders, as constructed in 1818, are, or were
lately (1854),still atwork on the Killingworth railway
dragging coals at the rate of five or six miles an hour.
(397.) One of Stephenson’s clear practical opinions was
Rejects the this, that the locomotive and the railway are part
steam-car- 0£ one mechanism^ and must be adapted to one an-
roads.°n other. He was not a friend to steam-carriages on
common roads, and the event proved his sagacity.
Iftheideaof a locomotive belongs to no one man,
still less does that of a railway, which being one of
the most elementary of mechanical contrivances,
may be traced, under some modifications, almost inde¬
finitely backwards, as a means of conveying heavy
loads with facility. Hence it was at first confined
chiefly to quarries and collieries, especially in under¬
ground passages or drifts. The gauge of these sub¬
terranean railways, or tram ways, was only about 18
inches. The material of the rails was first wood, then
cast iron, finally wrought iron, as being less liable
to wear and to accident. The wrought iron rail,
though not absolutely new, was first generally intro¬
duced in 1820. About the same time, or rather
sooner, the rails began to be made plain, that is,
without any vertical guide or flange to prevent the
wheels of the carriages from leaving the rail, and the
flange was transferred to the wheels of the locomo¬
tive. Even this was not new, for it had been used
by Jessop in 1789. The weight of the rails has
been constantly on the increase. The original cast-
iron rails weighed only 15 lb. a yard ; the malleable-
iron rail in 1821 weighed about 28 lb., then 35,
afterwards 64, and now rails of 80 lb. a yard are
generally used.
One of Stephenson’s first cares was to make his
Stephenson railwayS solid and level, and to prevent jerks at the
themtothejunc^on ^ie ra^s- The gauge he adopted, or the
locomotive, interval between the rails (now generally used, except
on the Great Western Baiiway and its branches), was
4 ft. 8| inches, and was derived from the accidental
width of the parent railways in Northumberland.
Like Watt and all other innovators, his great diffi¬
culty was to get the machinery of his locomotives pro¬
perly made, and the great railway movement of 1825
was anticipated by the establishment in 1820 of
an engine factory at Newcastle, which, till after the
(399.)
opening of the Liverpool and Manchester Railway in
1831, remained the only one, and for long afterwards
the best of its class. The cranked axle contrived by
Trevithick, and abandoned because it could not be
properly welded, was now restored; the heavy loco¬
motive was placed on strong but easy steel springs,
wrought iron was skilfully introduced into the wheels
of the carriages, and the whole machinery was made
to work with precision, and to combine a degree of
resistance never before anticipated with comparative
lightness. The factory was established in 1821, and
the first passenger locomotive was started on the Dar¬
lington and Stockton Railway in 1825.
I ought, perhaps, to apologize for these details, (400.)
but they illustrate so well the exceedingly gradual
progress of mechanical invention, that I have thought
them worthy of mention here.1 The subsequent his¬
tory of the locomotive and the railway is more gene¬
rally known. From the date of 1825, both grew and
flourished; the railway first and most steadily; the
locomotive was introduced more cautiously, and met
with much opposition; its triumph was almost en¬
tirely due to the steadiness of George Stephenson.
The year 1825, so fertile in speculation, produced (401.)
a series of projects for railways to an extent not com- Raiiway
monly known, since few of them came into existence
or were even commenced for many years later. Thei825.
projected capital of these companies amounted to not
less than L.30,000,000 or L.40,000,000. But the
only considerable undertaking which was at that time
seriously supported was the railway from Liverpool
to Manchester, and on that battle-field were fougbt
the great questions of the superiority of railways to
common roads,—of high to low velocities of trans¬
port,—and of locomotives to fixed engines.
On these three important points, George Stephenson (402.)
was in advance both of the science and of the prac-
tice of his age; and, accordingly, backed chiefly by°to
commercial men, who had entire confidence in his roads,
sagacity, he had to maintain the conflict almost single-
handed against general and professional prejudice.
With respect to the Railway, he had long decided in
his own mind against the use of steam-carriages on
common roads. This conclusion was scientifically
based on his own experiments on the friction of wag¬
gons on railways made in conjunction with Mr Ni¬
cholas Wood, civil engineer at Newcastle, as far back
as the years 1815 and 1816. A simple dynamometer Stephen-
of Stephenson’s invention was used, and by means of^n's^pe-
it the two fundamental propositions were established, the frjctjon
that the friction is directly as the pressure, and that it0f trains,
is quite independent of velocity (at least when the speed
was moderate). It may be said that these proposi¬
tions were already known; but, besides that probably
Stephenson and Wood were equally unacquainted
with the writings of Coulomb, they could not have
1 I have found many curious details of the early history of railways in a series of articles on the life of George Stephenson
in the Civil Engineer Journal for 1848 and 1849. I am indebted to Mr Robert Stephenson, M.P., for many interesting parti¬
culars respecting his father’s inventions.
Chap. IV., § 5.] MECHANICS.—GEORGE STEPHENSON. 885
dispensed with verifying his results under circurn- in essentials very little has been added by 25 years’
s ances so peculiar as those of a railway and a train of experience on lines of the same gauge. But now came
carriages. The necessity of doing so was manifested the struggle as to how this beautiful road was to be
‘J ® ^PP0®1^1011? an(^ even ridicule, with which the worked;—with horses,—by means of fixed engines,
i ea o notion being in this case independent of ve- —or by locomotives. It was not without a struggle
Jocity was^received, showing, as has been correctly that Stephenson gained his point. Even in 1829
S!T * ii sma^ was the amount of science at the prejudices of the engineering profession were still
that time blended with engineering practice.” The strong against the locomotive. And it is curious to
ic ion o e\en the indifferent railways of those days read in the contemporary documents with what dis-
amounted to only 10 lb. per ton of load ; consequently trust they were regarded. The clumsy expedient of
an inc ine o only 1 foot in 100 would increase by a series of stationary engines 1miles apart, dragging
one-halt the resistance to the motion of a carriage on the trains by ropes, would probably have been adopted
a railway. Hence Stephenson determined to con- to the disgrace of the age, but for the energy of Ste-
struct railways having only the smallest inclinations, phenson and his commercial friends. A competition The loco-
and to use fixed engines for higher slopes. With re- of locomotives was at last agreed to, which took m°tive
spect to common roads, he showed by powdering place on October 6, 1829, on a level piece of rail-c.ompeJ;i*
even a railway with sand, that the most power- way at Rainhill near Liverpool. Though the makers I829°at
u locomotives then in use speedily came to rest; of engines had their energies hampered by various Rainhill.
this with the previous objection, overruled in his needless conditions (particularly as regards the weight
1403 ) mi I P°SSlbl!ity °f advantaSe in that case- of the engines, under the mistaken notion, that velo-
Practica- low gradients and small resistances, together city could only be combined with lightness), several
bilityof | 1 tde Proved invariability of friction with speed, excellent engines appeared; but the “Rocket” made
high velo- there necessarily came into Stephenson’s mind the at Stephenson’s factory at Newcastle, not only gained
railways. F^bihtyof using high velocities. At a very early the prize, but far exceeded in its performances the
perio ( he spoke in one of his patents of con- limits assigned in the programme. It weighed 44-
veymg goods “ at nearly double the rate at which tons, and dragged a gross load of 17 tons, at the
they were then usually carried along railways,” in rate of 15 miles an hour, but moved itself with a
other words, at 10 or 12 miles an hour, and this he velocity of 35 miles an hour. The “ Novelty” of
states “ with no hesitation, speaking from experi- Messrs Braithwaite and Ericson was also very suc-
ments already made,” referring, no doubt, to those cessful. The prize was awarded to Stephenson, and
on friction made along with Wood about this time, this success was mainly due to the admirable inven-
Yet after nine years of farther experience, his old tion of the multi-tubular boiler, imagined by Mr
coadjutor Wood deserted him on this grand point, Booth, and carried out by Stephenson. To distribute
an in the first edition of his book on Railways (1825, the water of the boiler in tubes, and allow the heat of
p. 290) he disclaims the “ ridiculous expectation” the furnace to act around them, was an idea as old
that locomotives will be seen to travel at “ 12, 16, as the time of Watt, but it did not succeed. To carry The multi-
18, or 20 miles an hour,” and scorns “ the promulga- the hot air of the furnace through tubes surrounded tubular
tionof such nonsense.” Even in 1829 he reported to by water, was the more successful arrangement ofboiler-
Messrs Walker and Rastrick, who were referees on Booth and Stephenson, to the right working of which
theLiyerpool and Manchester Railway, “that nolo- the draught occasioned by the steam-blast in the '
comotive engine should travel more than 8 miles an chimney was essential. The idea, it is said, had oc-
hour.” If at this comparatively late period perhaps curred both in France and America, but it certainly
the most practised railway engineer in England held remained practically inefficient, perhaps on account
these opinions, and that with the full knowledge of his of the want of draught.
friend Stephenson’s matured convictions (which it is This invention, by increasing almost without limit (405.)
difficult to believe were not pointed at in this para- the evaporating power of the boiler, which is the StePhen-
graph), we may imagine the opposition which the key to the efficiency of a locomotive’ completed for cess"SUC'
plans of the latter were likely to meet with from in- the time the skilful improvements on locomotives ’
terested or even indifferent persons. and railways, which, as has been seen, we owe mainly
TheMa ^ & comPany was formed> and funds P™- to Stephenson. The comparatively trifling ameliora-
chester^nd^1^ to con.struct the Liverpool and Manchester tions which have occurred in either, and the stereo-
Liverpool Radway. It is unnecessary to state how successfully typed character of even the minor arrangements, such
Railway. Stephenson conquered the engineering difficulties of as those of stations and of passenger carriages,’show
the hne, and refuted the predicted impossibility of how much the sagacity of the engineer had antici-
crossing the Chat Moss. In every respect this rail- pated the accommodation of the public.1 (406.)
way became a model for those which succeeded, and I here close my account of Mr Stephenson and of
1 I do not overlook of course the modifications introduced in the broad-gauge system of the Great Western Railway. Mr
Brunei indeed tried to show how far he could deviate without positive injury from Stephenson’s plans; in some points, perhans,
he did so with advantage, yet, on the whole, the results do not shake Stephenson’s position as the commanding engineer of his time.
886
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
the railway system. The locomotive engine will ever
remain as an invention entirely distinct from those
created by the genius of Watt. It is in reality in¬
dependent of his great principle of separate conden¬
sation. It has a power of adaptation and a perfection
of performance more astonishing than any contrivance
of our time, except perhaps the electric telegraph.
In 1552, Jerome Cardan took twenty-three days to
travel from London to Edinburgh; that the same
should be done 300 years later in eleven hours, and
every day, is a fact as striking as any which the pro¬
gress of science presents. Whilst to Trevithick and
George Stephenson we are mainly indebted for these
results, the theory of the steam-engine is still in ar-
rear. To M. de Pambour we are indebted1 for by M. de Pam-
far the best account of the elements of force contained ^ur on 11x6
• -ipi . i • i i theory of
in the locomotive, and ot the resistances which they locomo-
have to overcome; but it is not to be doubted that tives.
much yet remains to be done in this direction.
George Stephenson died 12th August 1848, at the (407.)
age of sixty-eight, and generally respected for his®nson
private character as well as for his talents. His son 1848_
had the honour of completing the second great railway
work in Britain, from London to Birmingham, and
by the invention of the tubular bridge, described in
a previous section, he has added the most important,
as well as the most scientific auxiliary to the exten¬
sion of railways since 1830.
§ 6. Hydrodynamics, Dubuat, Venturi, Professor Stokes.—Friction and Resistance of Fluids.
MM. Weber, Mr Scott Russell.—Propagation of Waves. Influence on Canal Naviga¬
tion. MM. Fourneyron and Poncelet.—Improved Hydraulic Machines; Turbine. Reference
to the subject of Capillary Attraction.
(408.) There are few subjects less adapted for the kind
Progress of 0f discussion which I have adopted in this Disserta-
Hydrody- ^on Hydrodynamics, whether in its abstract or
practical form. Not only is it difficult to fix upon
individuals who, in the more recent progress of the
subject, have attached themselves to it in so especial
a manner as to have impressed the science with the
individual character of their own minds, but the pro¬
gress made in either branch has been of a remarkably
fragmentary kind, usually bearing upon the solution of
individual problems, and tending to the improvement
of particular machines. It must be owned, too, that
however important in practice may be the efficiency
of a water-wheel or the discharge of a pipe, the so¬
lution of such problems does not present the attrac¬
tive interest which attaches to many less difficult ones
in Natural Philosophy. As regards more general pro¬
blems of which a direct solution from first principles
might appear possible, it has been found that these
are as yet so limited as to give a character (which is
generally admitted) of great barrenness to the theo¬
retical investigations.
(409.) While, then, I shall endeavour, in conformity with
my general plan, to preserve something of the bio¬
graphical character in the history, suppressing details
and many minor and even some important steps,
this section will necessarily have somewhat of a frag¬
mentary character, and its deficiencies must be sup¬
plied by a reference to the numerous articles of the
Encyclopsedia which treat more or less fully of these
subjects and their history.
1.
Friction and Resistance of Fluids.—The first
name I shall mention is that of the Chevalier Du-
(410.)
Dubuat—
and resist- BUAT, who has the signal merit of having attri-
ance of buted due importance to, and of having considered
fluids.
with much sagacity, the effects of the friction of
fluids against their own particles, and against the
sides of the solid bodies used to confine them. He
had the full advantage of an acquaintance with the
Abbe Bossut’s excellent experiments and judicious
writings, but he was, I believe, the first who suc¬
ceeded in ascribing to the different forces which act
on fluids in a state of uniform motion their effective
share in determining their velocity. I refer particu¬
larly to the discharge of pipes and of rivers. Du-Theory of
buat showed that when the motion of water in suchrivers-
circumstances becomes uniform, the accelerating force
which acts is the measure of the total resistances to
the fluid motion, whether arising from the inequali¬
ties of the bed or the viscosity of the fluid. These re¬
sistances are assumed to be proportional to the square
of the velocity. Since they are exactly in proportion
to the length of the pipe or channel, and since the
moving pressure increases in the same proportion, the
velocity is independent of the length ofthe pipe, whilst
the inclination remains the same—a simple result not
previously noticed. In the case of a pipe the head
or superincumbent pressure may be divided into two
parts; one, requisite to force the water into the tube
with the requisite velocity, which is independent of
the distance to be travelled; the other, which balances
the resistance due to the length of the pipe, which
for a given diameter varies as the length, or if the
slope be constant is independent of the length.
The relation of the area of the stream to the peri-
meter or rubbing surface of the channel is then taken ^rauljc
into account. This ratio is called by some writers the depth.
mean hydraulic depth. The manner in which Dubuat
derives his formula (which I shall not here set down)
from direct experiment, guided by a few general no¬
tions of theory, is a very good specimen of this kind
1 The Theory of the Steam-Engine (1839), and A Practical Treatise on Locomotive Engines (1840), by the Comte F. M. G. de
Pambour.
Chap. IV., § 6.] MECHANICS (OF FLUIDS.)—DUBUAT—VENTURI—MR STOKES. 887
of induction, without any pretence whatever of pro¬
ceeding upon the mathematical theory of fluids in
motion. The same views were ably expounded and
enlarged by Dr Robison in his excellent article on
Rivers and Resistance in this Encyclopaedia, through
which principally the theory of Dubuat became known
in this country. Indeed, viewed apart from the tech¬
nical value of the enquiry, the research as to the na¬
tural economy of rivers is a wonderful and striking
branch of terrestrial physics, and one which had long
afforded a subject of anxious and perplexing enquiries
to Italian engineers from the time of Leonardo da
Vinci, though comparatively little studied elsewhere.
The collected treatises of Italian authors form an
important body of hydraulic information.1 The rivers
of the north of Italy, like those of Holland, conveying
vast masses of water charged with mud under very
feeble slopes to the sea, present a formidable difficulty
which compels attention,—vast territories being in¬
creasingly subject to inundation, as the beds of the
rivers are raised by deposition above the general level
of the soil.
(412.) Dubuat’s formulas have been modified, and made
formula;3 to rePresent experiments better, by subsequent writers,
improved, particularly by De Prony, Langsdorf, Eytelwein, and
Thomas Young; and the discharge from mere orifices
has been discussed by numerous authors who have
given empirical co-efficients to represent the pheno¬
mena. But little has been added to a philosophical
view of the real laws which govern the fluid motion
in this case. Nevertheless Savart and Magnus have
made some ingenious observations on the constituent
parts of effluent streams.
(413.) Tfle viscosity or imperfect fluidity of water is the
of fluids^— ProPerty most difficult to be taken into account in
Venturi  these and other hydraulic problems. It is that which
Coulomb, causes the velocity of a stream to diminish from the
surface to the bottom, and from the centre to the
sides ; these proportions were also sought by Dubuat.
Each layer of water in motion exerts a dragging or
“ tangential force” upon other layers, which from
any cause are comparatively quiescent; and the ex¬
periments of Venturi about the end of the last cen¬
tury, showing that a stream in motion draws towards
it the particles of still water with which it may be in
contact, with a force sufficient to overcome consider¬
able hydrostatic pressure, attracted much attention.
About the same time Coulomb, with his usual ad¬
dress, made experiments on the friction of fluids by
observing the rapidity with which cylinders oscillat¬
ing by means of torsion in different fluids had their
original motion destroyed.
(414.) Intimately connected with the friction, and conse-
Threc cases quent mutual action of fluids, is the resistance which
distance to" 0®'cr to passage of solid bodies through them,
and this favourite problem of mathematicians was
treated by Dubuat, in his inductive way, in an able
and practical manner. Three cases may be specified
on account of their theoretical or practical import¬
ance :—1st, In the case of a body oscillating like a
pendulum, with small velocities, the body being im¬
mersed in a resisting medium; 2c%, The resistance
to vessels floating on and propelled through water;
3cZ(y, The resistance of the air to projectiles whose
velocity is very great.
Under the first head Dubuat made those ingenious (415.)
experiments long overlooked, but lately brought into Motion of
notice, which I have mentioned in the section on thePendulums>
Pendulum in the chapter on Astronomy, Art. (246).
The cause of the neglect of these striking and original
observations has probably been correctly stated, by
saying that in them the pendulum was made subser¬
vient to hydraulic experiments, and not the theory of
fluids to the improved use of the pendulum ; and they
were therefore overlooked by those whose studies were
connected with the pendulum and its applications.
The fact observed by Dubuat was, that a large mass
of air (or of water in the corresponding case) is car¬
ried along with a pendulum in motion, and affects
in a sensible manner the time of vibration, quite in¬
dependent of the diminution of gravity due to the
buoyancy of the pendulum. The moved mass of air
was proved by hanging a film of worsted from an
arm a foot long in advance of the moving sphere,
when it was found to be but slightly driven by the
inertia of the air through which the pendulum moved.
Dubuat significantly calls the mass of moved air “ the
prow” of the moving body, and it is easy to antici¬
pate the sort of effect which such a graduated con¬
dition of the surrounding air from motion to absolute
rest would produce.
But the most surprising thing is, that mathema-
ticians should have attempted to compute the effect, Professor
or should have been in any degree successful in doing Stokes’s so-
so; yet after the preliminary efforts of Poisson and
Green, Professor Stokes has introduced for the first mete o/
time a correct definition of the “ index of friction”
a fluid, and after great labour has succeeded in find¬
ing exact expressions for the motions of a solid sphere
and cylinder. This investigation may be found in a
very elaborate paper in the Cambridge Transactions,2
in which he solves the equations found by him in a
previous paper,3 in the cases of pendulums having
the forms just mentioned. Another interesting re¬
sult of his investigation is the immense effect of fluid
friction in retarding the fall of minute rain drops,
which he states to be such as to explain satisfactorily
the suspension of clouds. In the second part of the
paper I have first cited Mr Stokes proceeds to com¬
pare his theory with the observations on the pen-
solids. 1 Raccolta di Autori che trattano del moto dell’ acque, 10 vols., 1822-26 ; and Nuova Raccolta, 7 vols., 1823-45. See also the
„ admirable methodized catalogue of writers on Hydraulics in the second volume of Young’s Lectures on Natural Philosophy,
2 Vol. ix. part ii.— On the effect of the internal friction of Fluids on the motion of Pendulums.
3 On the friction of Fluids in motion. Camb. Trans., vol. viii., part ill.
888
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(417.)
Naval ar¬
chitecture.
(418.)
Resisted
motion of
projectiles.
(419.)
Experi¬
ments on
waves in
water.
(420.)
Observa¬
tions of
MM. We¬
ber on the
form of
waves.
dulum mentioned in Art. (246), and the agreement
appears satisfactory. With reference to Coulomb’s
experiments on oscillating disks there remains some
doubt whether the theory applies satisfactorily to
viscid fluids such as oil.
On the very difficult and still empirical subject of
naval architecture as regards forms of least resist¬
ance, I shall not here speak; but one very interesting
case of the resistance of fluids in canals will be noticed
in the course of this section—Arts. (422), &c.
The theory of military projectiles has perhaps re¬
ceived no improvement so considerable during the
last 100 years as by the previous experiments of
Robins, and the invention of the Ballistic Pendulum
referred to in the preceding Dissertation; though the
experiments of Borda in France, and of Hutton in
this country, have of course increased the technical
precision of artillery. Poisson has considered, in a
mathematical way, some of the simpler cases of pro¬
jectiles moving with a moderate velocity.
II. Experiments on Waves.—MM. Weber—Mr
Russell.—Whilst the theory of the dilated and com¬
pressed waves which constitute sonorous vibrations
in elastic fluids was being successfully investigated
by Lagrange and Laplace, the case of waves in water,
due to a disturbance of hydrostatic pressure only,
was attacked by the same mathematicians with far
less success. It is generally allowed that the more
recent and abstruse researches of Poisson and M.
Cauchy, though very valuable as improvements in
pure mathematics, have been also singularly barren
of valuable results admitting of the very desirable
confirmation of direct experiment. The greatest of
all hydrodynamical problems, that of the Tides, is, as
has been seen in the second section of the chapter on
Physical Astronomy, Art. (69) &c., so excessively
complex as to be the last, instead of the first, which
analysis might have been expected to resolve.
When, on the other hand, we see the light which has
been thrown even upon it by experiments on a com¬
paratively small scale, we learn to value them in
proportion to their rarity.
The brothers Ernst HeinrichWeber and Wilhelm
Weber, known for many ingenious experiments in
physics, and particularly in magnetism, are the authors
of a useful book on waves.1 They made experiments
on the velocity of waves in glass troughs, by means of
which they determined in several cases the velocity
of the wave with different depths of fluid; they also
ascertained mechanically the form of the wave, which
they found to be that of the curve of sines. But the
most important of the Webers’ experiments is pro¬
bably the determination of the motion of individual
particles of the water, which they ascertained by
watching from the exterior of the glass trough the
curve described by minute floating particles as the
wave passed over them. The usual form of the trajea- Trajectory
tory is an ellipse having the greater axis horizontal, the ticfepar'
whole ellipse being described when the wave includes
a ridge followed by a depression of the surface; but
if there be only an elevated wave propagated, then a
semi-ellipse is described in the direction in which
the wave moves, and the particle returns to rest in a
new position; if the wave be a hollow one the con¬
verse takes place. The limits of oscillation diminish
with the depth of the fluid, particularly the vertical
limits; consequently at some depth the motion of
the particles is nearly in a short straight line. The
rapidity of the degradation of the individual motions
depends on the relation between the length of a wave
compared to the depth of the fluid : where the wave
is very short compared to the depth of fluid, the el¬
lipses near the surface become circles, and the mo¬
tion rapidly disappears beneath; when the length of
the wave is great compared to the depth of fluid,
the motion of the particles is nearly the same from
top to bottom. The conclusions of theory are on the
whole confirmed by these experiments.
The experiments of Mr John Scott Russell, so (421.)
far as we shall notice them, refer to two closely con- ^s^,'g
nected subjects :—the transmission of waves, and experi-
the resistance of water to vessels propelled through ments on
it as affected by waves. They are principally to be waves-
found in the Edinburgh Transactions, vol. xiv., and
the British Association Report for 1837. The velo¬
city of waves in troughs of different depths and sec¬
tions was ascertained by allowing the wave to be re¬
flected at either end of the trough, which does not in
any way affect the time of its propagation, and gives
great facility for accurate observation, as the distance
travelled over may thus become large, at the same
time that all casual and interfering waves are gra¬
dually eliminated. The instant of the passage of
the wave was ascertained by reflecting the light of a
candle vertically upwards from its horizontal sum¬
mit. The length of the trough was 20 feet, but
since the wave was made to traverse it as often as
60 times, a distance of 1200 feet was really ob¬
served. The waves were single or “solitary”
waves, either “ positive” produced by a gush of
water from behind a sluice, or “ negative” by with¬
drawing water suddenly. Mathematicians seem not
agreed as to whether or not the “ solitary” waves of
Mr Russell are to be treated as a species apart.2
Unquestionably it has long been known that a par¬
tial wave either positive or negative may be propa¬
gated without any farther disturbance of the fluid.
Theory also shows that the velocity of a wave long in
proportion to the depth of the water is nearly as the
square root of the depth ; but it does not clearly ap-
1 Wellenlehre auf experiments gegriindet, oder iiber die Wellen tropfbarer Fliissigkeiten mit anwendung awf die Schall und Licht-
wellen. Leipzig, 1825.
2 Compare Mr Airy in the article “ Tides and Waves,” Encycl. Metropolitana; Prof. Stokes in British Assoc. Report for 1846,
and Mr Earnshaw in Cambridge Trans., vol. viii.
Chap. IV., § 6.] MECHANICS (OF FLUIDS).—MR RUSSELL—M. FOURNEYRON. 889
j)ear whether the disturbed or undisturbed depth is
Compared to be taken. The analysis of Mr Airy seems to show
bj^Mr^Ket- a depth somewhat greater than that due to the
land and utmost effect of disturbance is to be preferred. Mr
Mr Airy. Russell also made experiments on the propagation of
waves in channels of different forms of section. Pro¬
fessor Kelland has given a very simple expression
for the velocity of the wave in this case,1 which on
the whole agrees with experiment.
Peculiar Sometime about the year 1830, attention was
effect of" ^rawn to a singular fact connected with the resist-
wave trans-ance °f water in the case of canal navigation. It
mission on was first noticed I believe in Scotland, probably on
gation118^* -^'or^1 an<^ Clyde Canal. It amounted to this,
that whereas at moderate or rather slow velocities,
the resistance to a boat increases with the square
of the velocity,—after a certain point, not differing
very much from 7 miles an hour, the resistances not
only cease to increase according to the same rapid
law, but actually dimmish to some extent when the
speed is greater. Different experiments were made
by the canal proprietors with a view to meet in some
degree the active competition by railways, then com¬
mencing. Mr Russell was employed by the directors
of the Forth and Clyde Canal, and to his experiments
we now refer. It appears from his tables that the
resistances increased on the whole faster than the
squares of the velocities up to 7^ miles an hour,
when they suddenly diminished between 7-<r and Si¬
miles an hour by one-fifth part in one experiment,
and by no less than one-third in another.2 It was
not until about 12 miles an hour, that the resistance
reached the same amount as at 7i miles.
Practical occurrence of this singular transition was at-
results. tended with a phenomenon easily noticeable. In
every ordinary case a boat in a canal drives a wave
before it, which is in fact a heap of water resisting
the boat by increasing the pressure against its bows,
which wave may be called a forced wave, having this
peculiarity that it travels with the speed of the boat
and never quits it; whilst a free wave, by whatever
cause excited, is propagated at a rate depending only
on the dimensions of the canal, particularly its depth.
Now the diminished resistance takes place when the
boat is by the force of traction partly drawn out of the
water, and lifted up upon the wave to which its own
motion gives rise. It is said to ride upon the wave,
and the head of water pressing against its bows is
visibly diminished. The most advantageous rate of
transport was found to be about one-third greater than
that required merely to mount the wave, which last
depends principally on the depth of the canal. Thus
on three different canals, 3 J, 5|, and 9 feet deep,
the most advantageous velocities were 8, 11, and
15|- miles an hour. The actual velocities of the
free wave were ascertained by Mr Russell in an in¬
genious and satisfactory manner. When the boat is
dragged to most advantage, the draught of water is
less at the stem and stern than in the centre. All
these circumstances have been very ingeniously and
satisfactorily explained by Mr Airy in his paper on
Tides and Waves, articles (404—411).
Many persons (amongst whom are Colonel Henry (424.)
Beaufoy, Mr Scott Russell, and the American ship- Forms of
builders) have bestowed much attention on the forms shiP3-
of vessels for ensuring speed, especially by the avoid¬
ance of waves of various kinds generated by steam-
vessels in motion. Every one who can compare the
performance of such vessels during the last twenty
years, and the still surface which waters navigated
by steam vessels now present, as if they were merely
cut open and closed again before and after the passage
of the ship, instead of being tossed into dangerous bil¬
lows consuming uselessly the propelling force, will
readily admit that, however imperfect the theory, prac¬
tical art has made real progress in this direction.
III. Improved Hydraulic Machines—Turbine.— (495 -)
Before concluding this section, I will refer to the Improved
most considerable improvement made of late years hydraulic
in the application of hydraulic pressure to motive
purposes, and I shall couple it with the names bine,
of two French engineers, MM. Fourneyron and
Poncelet, the former the inventor of the Turbine
(the machine referred to), at least in its improved
practical form; the latter an important contributor
to the useful application of hydraulics, an accom¬
plished mathematician, and the author of several
standard works connected with industrial mechanics.
The defects of common vertical water-wheels, (426.)
whether overshot or undershot, are so great and Defects of
so notorious, that only their simplicity, and thecommon
fact that in very many cases water-power costs wheels 
next to nothing, and may be squandered with im- Barker’s
punity, could justify their use. The advantage of
using the simple pressure of a fluid as a moving
power had been foreseen in that application of re-ac¬
tion called Barker’s which, though well known
in models, was seldom if ever applied in practice.
Mathematicians were, however, aware that it offered
important advantages. Of late years a patent has been
taken out in Scotland for a modification of it, which
is found, I believe, to work well. But the Turbine
or horizontal water-wheel imagined by Burdin and
Fourneyron, and brought to a high state of perfection
by the latter about the year 1833, appears to exhaust
all that is valuable in this mode of applying water.
Referring to other parts of the Encyclopaedia (427.)
for the details, I may here explain generally that Fourney-
the Turbine consists of two parts, one a fixed cy- r?n s tur'
linder or drum of small height compared to its bme'
diameter; the other a portion of a cylinder ex¬
terior to the former, and moveable round it, so that
water at the surface, and g the accele-
5 u
1 Velocity V ^ ^ ; where A is the area of section of the canal, b the breadth of the
rating effect of gravity. Edinburgh Trans, vol. xiv.
2 Edin. Trans., vol. xiv., p. 48.
VOL. I.
890
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
the inner surface of the moveable cylinder is all hut
in contact with the circumference of the fixed cylin¬
der. Further, water under a greater or less hydro¬
static pressure, and moving with the consequent velo¬
city, is introduced at the centre of the fixed cylinder,
and conveyed to its circumference by channels of a
peculiar form constructed by means of vertical parti¬
tions or guides of continuous curvature, from which
the water is discharged against float boards within
the external cylinder, which are also curved, but the
curvature is turned the other way so that the parti¬
tions in the first cylinder are where they terminate
nearly perpendicular to the internal surface of the
moveable or second cylinder where they commence.
These latter partitions or float-boards terminate ex¬
teriorly in a direction nearly tangential to the outer
cylindric surface where the water emerges.
(428.) The hydraulic principle of greatest possible advan-
Principle tage -which these Turbines are made as nearly as
advantage* P0SSiWe to approximate is this, that the water shall
in water- enter the moveable apparatus without shock, and shall
wheels. qUit it without velocity, being simply left behind by
the wheel as it escapes from it. Since both these con¬
ditions cannot absolutely be fulfilled, the first part of
the condition is left imperfect. Some secrecy is, I
believe, still maintained as to the forms and dimen¬
sions of these machines ; but their actual efficiency
has been most thoroughly tested by means of De
Prony’s Friction Dynamometer1 by Colonel Morin, a
most competent authority. His experiments leave no
doubt of the admirable qualities of these machines.
In particular, the useful effect compared to the theo¬
retical effect represented by the fall of water expended
rises higher than probably in any other hydraulic
machine, being under favourable circumstances about
eighty per cent. Now water-wheels moved princi¬
pally by the shock of the fall seldom, in the most
advantageous conditions, realize thirty-five percent.,
often not seven per cent. This superiority of action
of the Turbine is due entirely to the approximation
which it gives to the theoretic condition above men¬
tioned of perfect efficiency.
(429.) But what is not less striking in the performance
Power of 0f this machine, is the variety of circumstances under
of thcTu'r- whlch it acts advantageously; however great may be
bine. the variation in the size and velocity of the wheel, the
height of fall, and the power disposable. Turbines
have been made of as small diameter as 2 feet with the
enormous fall of 350 feet, making 2300 revolutions
per minute. They work with nearly equal advantage
(relatively to the power expended) whether the supply
of water be small or great. They may be completely
drowned or buried under water to a considerable
depth without any sensible variation in their effi¬
ciency, thus preventing any inconvenience from floods.
It is remarkable that, with these manifest advan- (430.)
tages, the Turbine has been so sparingly introduced at
least in this country. No doubt the first establish¬
ment of it is attended with considerable expense.
M. Poncelet, an active and intelligent officer of (431.)
Genie, and member of the Institut, is favourablyPonce*
known by his hydraulic observations and inventions,
as well as by his skilful investigation of the effects breast-
of machines, and his excellent works and memoirs wheels,
on several subjects. He has investigated with much
patience and geometrical nicety the form and dis¬
charges of spouting fluids, and was one of the first
to improve materially the ordinary water-wheels, by
introducing a kind of breast-wheel (which thirty-five
years ago was scarcely known in France) in which
the water is conveyed without shock into compart¬
ments on the descending side, from which again it
was allowed to escape with all its acquired velocity
spent, or nearly so. The efficiency of these wffieels is
equal to about two-thirds of the power expended.
Before the Turbine had been finally improved by M.
Fourneyron, M. Poucelet had invented an engine on
the same principle, in which the water enters at the
circumference of the horizontal wheel, and is deli¬
vered at the centre.
I am aware how imperfect this section remains as (432.)
a history of Hydrodynamics. But I must again Capillary
refer to special articles on the subject, the plan of attraction
the Dissertation not admitting of farther detail. As and
nothing material has been added to the doctrine of place.
Capillary Attraction since the publications alluded
to in Sir John Leslie’s Dissertation (although M.
Poisson has written a treatise on the subject), I will
for the sake of compression not enlarge upon it. I
do so with the less regret, because I cannot regard
the excessive mathematical illustration which it has
received as altogether justified by the certainty and
due appreciation of the physical principles involved,
such as can alone give to applied mathematics their
distinctive value. The theory of Laplace, so far
as it was based on novel grounds, was anticipated
by Dr Young, and gave rise to several controversial
articles by that most eminent philosopher, of which
an account will be found in Dr Peacock's Life of
Young, pages 199-210, as well as a most excellent
review of the subject of Capillary Attraction, which,
indeed, by its candour and completeness, supersedes
anything which I should have felt disposed to say
on the subject.
1 Gaspard de Prony, born in 1755, was an eminent engineer, especially in the department of hydraulics, and the author of a
voluminous work entitled Nouvelle Architecture Hydraulique; but his originality was not great enough to authorize his being
placed among the leaders of his age. His simple invention of the Frein Dynamometrique, or friction dynamometer, is the one
by which perhaps he will be longest remembered. It consists of an iron collar with tightening screw, which may be clasped
on a horizontal wooden arbor connected with uniformly revolving machinery. A lever, to which a weight may be applied, is
attached so as to form part of the collar. The clasping screw being moderately tightened, the collar and lever are of course
carried round by the machinery until a weight is applied sufficient to check the velocity, and to generate an amount of friction
which is in fact the useful effect of the machine for that velocity, and which is determined by the momentum of the weight over¬
come in one second. De Prony was a most amiable man, and died in 1839, in the 84th year of his age.
Chap. IV., § 7.] MECHANICS (ACOUSTICS).—CHLADNI—SAY ART.
891
7. Progress of Acoustics. Chladni—Savart. Laplace's Correction of the Theory of Sound.
Vibrating Plates and Acoustic Figures. Cagniard de la Tour’s “ SireneP
(433.) The mathematical theory of the propagation of
Mathema- sound, considered as a branch of analytical mecha-
ofthe'prcJ11*08’ ma<^e ^ar greater progress during the eighteenth
pagation century, in harmony with the general character of
of sound, the science of that period, than the inductive doc¬
trines of acoustics. Newton here, as in other de¬
partments, overstepping the limits of knowledge of
his day, left a legacy of toil to his immediate suc¬
cessors. Lagrange had the most distinguished good
fortune in reducing the theory of aerial tremors under
their most general conditions to the laws of mecha¬
nics by the calculus of partial differentials ; and La¬
place supplied the link which was wanting to recon¬
cile the result with the known mechanical properties
of air. As the former of these matters belongs more
properly to the period of the previous Dissertation,
Laplace’s and as the beautiful discovery of Laplace has been
ofUie^011 nJOre esPecially touched upon by Sir John Leslie,
theory. ^ wiU he sufficient here to recall the fact that the
spring of air, or the effort by which it tends to re¬
expand under sudden compression or to contract to
its former bulk when suddenly dilated, is increased
by the heat extricated in the former case, as well as
by its absorption in the latter. And as sonorous
pulsations are held to consist of a series of com¬
pressed and rarified waves whose velocity is affected
by the recoil of air, it appears certain that the velo¬
city must be increased by this circumstance, though
it is difficult to determine experimentally the exact
amount.
(434.) The revival of experimental acoustics is due to
Chladni Ehnst Chladni a native of Saxony, but of Hungarian
of experi- extraction, born in 1756. Little had been done in
mental this department since the time of Sauveur, who as-
acoustics. certained the nature of the harmonic vibrations of
strings, and that of Daniel Bernouilli, who considered
the analogous case of organ pipes. We are indebted
to Chladni for two classes of original experiments—
his measure of the velocity of sound in a variety of
bodies by peculiar and ingenious methods; and his
observations on the vibrations of plates by means of
the ingenious expedient of strewing them with sand
and other powders.
We shall say a few words under each of these
heads :—
(435.) I. Chladni observed the velocity of sound in air
sound1 in °f different densities, and in different gases, by using
different a flute °f metal which was sounded by means of the
media; elastic fluid required, and the resulting note enabled
him to determine by an easy calculation the speed of
propagation of the tremor. This method (using an
organ pipe) has been more lately resorted to by
Dulong for the purpose of deducing the properties
of different gases with respect to heat, by ascertain¬
ing from experiment the co-efficient in Laplace’s
correction for the velocity of sound. Chladni was
also probably the first to notice the longitudinal os¬
cillations of strings and rods which always yield a
note immensely sharper than the lateral vibrations.
By means of the former he ascertained the velocity
of sound in a variety of woods and metals, in some
of which it is no less than seventeen times greater
than in air. These observations are not only inte¬
resting in themselves, but as throwing light on the
constitution of solid bodies. To Chaldni we like¬
wise owe a knowledge of the twisting vibrations of
rods, which exhausts the modes of vibration of such
bodies. To connect theoretically the periods of these
different kinds of movement, has been a favourite
problem with recent mathematicians, but has not even
yet been quite successfully performed.
The determination of the velocity of sound in (436.)
water, an experiment by no means difficult, was re-In water'
served for MM. Colladon and Sturm, who ob¬
served it on the Lake of Geneva, and found it to be
4708 English feet per second, a result closely con¬
forming to the theoretical amount deduced from
Oersted’s observation on the compressibility of water.
II. But Chladni’s experiments on the vibrations (437.)
of plates are of still greater interest and originality. Chladni on
Though it has been aftirmed that Galileo strewed ^oenv^ra'
sand or light substances upon the sounding boards plates,
of musical instruments,1 Chladni deserves the entire
credit of rendering this an exact method of ascertain¬
ing the nodal lines or points of rest in bodies vi¬
brating in a stable or permanent manner. He first
applied it to plates round, square, or of different
figures, supported horizontally and caused to vibrate
by applying a violin bow to their edges. Dust or fine
sand strewed or sifted uniformly over such a plate,
arranges itself in a variety of beautiful figures, being Acoustic
tilted from the greater part of the surface, and heaped fiSures-
up on those parts which are at rest in consequence of
the vibratory motion of adjacent parts taking place
simultaneously in opposite directions ; just as the
nodal points of a string vibrating harmonically are
without motion on the same account. The number
and variety of figures thus producible in the same
plate is very great, and corresponds, as Chladni
clearly saw, to different simple harmonical vibrations
of the elastic plate, being accompanied by their ap¬
propriate notes; or by the superposition of several
such modes of vibration, and of the corresponding
sounds. The tract published by him in 1787 en-
tituled, Entdeckungen iiber die Theorie des Klanges,
contains numerous figures of these appearances, which,
1 This, however, is very doubtful. See Dove, Repertorium, iii. 106.
892
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(438.)
In bodies
possessing
unequal
elasticity.
(439.)
Chaldni on
meteoric
bodies.
(440.)
Young—■
Robison.
(441.)
Savart.
Propaga¬
tion of
sound in
masses of
air, &c.
more recently, Savart found the means of preserving
bv transferring them to sheets of gummed paper.
There are few experiments in physics of a more
striking character, or which so plainly reveal minute
and complex motions so small and so rapid as to
be difficultly appreciated otherwise. Mr Faraday
and Mr Wheatstone have pursued the same enquiry
experimentally, and the latter has satisfactorily de¬
duced the figures of Chladni’s square plates from the
mechanical superposition of simple modes of vibra¬
tion which are symmetrical and isochronous. (Phil.
Trans. 1833.) By so doing he has succeeded better
than the mathematicians, whose results on this sub¬
ject have been very little practical.
Chladni was the first to make experiments on the
vibrations of bodies whose elasticity varies in dif¬
ferent directions. Thus he cut plates out of different
kinds of wood, and found the nodal curves unsym-
metrical in different directions depending on the
course of the fibres. The experiments were naturally
afterwards employed to illustrate the theory of ellip¬
soidal waves on the undulatory hypothesis of Optics.
The experiments of Chladni procured for him the
especial notice of Napoleon, by whose wish one of
his works was translated into French. He died in
1827, and besides his acoustical discoveries, he will
be remembered by the sagacity and boldness with
which he maintained the popular opinion of the
fall of heavy meteors from the sky, contrary to the
prevalent scepticism of philosophers. Chaldni’s suc¬
cess in establishing this important fact in natural
history is due, like his other physical inductions, to
the constancy and simple-mindedness with which he
attached himself to a strictly definite enquiry.
We must not here enlarge upon the ingenious and
important investigations ot Dr Thomas Young con¬
nected with acoustics. Being chiefly connected with
his admirable Theory of Light, they will be noticed
in the chapter on Optics. The peculiarly practical
and sagacious views of Dr Robison connected with
the Theory of Musical Instruments and Acoustics
generally, must also be passed over.
In Felix Savart we find a man like Chladni who
was especially devoted to a single and circumscribed
branch of science^acoustics. Hispublishedresearches
are almost all detached notices in the Annales de
Chimie, with a few memoirs in the publications of the
Institute; and whilst they are very interesting, exact,
and instructive, I doubt whether it would be possible
to place the results in a connected and comprehen¬
sive view before the reader. They are therefore rather
to be sought in the special articles of the Encyclo¬
paedia devoted to the subject. In general they may
be stated to refer to the following topics :—(1.) To
the manner of propagation of sound through the
air and through liquids, with an attempt to explore
the manner in which sounds spread in apartments
of different forms; an enquiry as difficult as it is
important; (2.) To the generation and audibility of
musical notes. Previous authors (for example, On the pro-
Chladni, Biot, and Wollaston) having differed mate- muucV°° 0
rially as to the range of audibility of repeated equi- noteSt
distant impressions which affect the human ear as
musical notes, Savart used a simple method, no
doubt original to him, but anticipated I believe by
Robison, in which a card is held near or touching
a revolving wheel, and the number of impulses
(each double) given to the air by every tooth as
it passes the card, is readily measured. He thus
found that a note occasioned by 24,000 double vi¬
brations in a second is perfectly audible; and, at
the other limit of the musical scale, from seven to
eight equidistant beats constitutes a sound having
a distinct fitch. According to Savart, two conse¬
cutive double impulses of whatever duration are suf¬
ficient to convey to the ear the sensation of pitch.
But a more elegant and accurate instrument for
the numeration of sonorous pulsations is the Sirene Sirene of
of M. Cagniard de la Tour, unquestionably one of
the most exact and satisfactory additions lately made Tour
to our experimental apparatus. In it a current of
air is repeatedly interrupted and renewed, giving
rise to a series of impulses similar to those of the
toothed wheel; and this apparatus is ingeniously
contrived, so as to maintain its own motion, and
record its indications. It is by far the most accu¬
rate known method of ascertaining the pitch of a
given note. It may also be worked with water.
Robison had also the merit of the primary idea of
the Sirene, by making a stopcock revolve rapidly
whilst applied to a tube emitting a blast of air. (3.)
Savart extended the researches of Chladni by means )7lvar^on_
of sand to many new cases, and with interesting a
results ; in particular he exhibited the effects of the soiids.
unequal mechanical elasticity of crystals cut in dif¬
ferent directions. He has also examined with great
care and ingenuity, the nature of the vibrations which
occasion the accumulations of sand on the nodal
lines of plates, and he comes to the conclusion that
they are determined by simultaneous transverse and
longitudinal movements (the latter of which are pa¬
rallel to the surface of the plate). In proof of this
he shows that in long rods or hollow cylinders, the
position of the nodes is intermediate and opposed
upon the contrary sides of the rod or hollow cylinder.
Savart made many experiments on the communica¬
tion of vibrations from one body to another ; showing
that the molecular movements generally preserve
their parallelism, so that a longitudinal vibration of
one body may give rise to transversal movements in
another ; and he applies this to the theory of musi¬
cal instruments.
Savart was born at Mezieres in the department of (442.).
Ardennes, on the 30th June 1791 ; and died some-
what prematurely on the 16th March 1840. He 0f gavart.
had some peculiarities of temper, amongst which
was his unconquerable prejudice to everything Eng¬
lish. He did not even acknowledge the intimation
Chap. V., § 1.]
OPTICS.-
■YOUNG.
893
of his election as a foreign member of the Royal
Society of London. It is to he regretted that Savart
never published a connected account of his obser¬
vations. He had caused to be collected at the College
de France, where he was professor, an unequalled col¬
lection of acoustical apparatus, a great deal of which
was contrived by himself, and where he delivered
extensive courses of lectures on this subject alone.
Several English philosophers, in particular Pro- (443.)
fessor Willis, Mr Hopkins, and Mr Wheatstone, have 0ther4
written several important detached memoirs on par- experi-08
ticular practical points, for which we must refer to ments.
special treatises.1 The first and last of these gentle¬
men, together with some Germans, have approxi¬
mated in some degree to the formation (on empirical
principles) of a speaking machine.
CHAPTER Y.
OPTICS.
§ 1. Thomas Young.—The TJndulatory Theory of Light.—Its history from the time of Hooke
and Huygens.—The Law of Interference.—Its application to Diffraction—to the Rainbow
—and to other subjects.—The Theory of Polarization referred to another section.
(444.)
Small pro¬
gress of
optics in
the 18th
century.
(445.)
Thomas
Young.
The history of Optics in the eighteenth century is
one of the blankest pages of scientific story; at least
if we allow Bradley’s discovery of aberration to be (as
it really is) rather an astronomical than an optical
discovery. The most notable advance was unques¬
tionably the invention of the achromatic telescope
as narrated in the Fifth Dissertation,2 founded on
the proof of Newton’s oversight in the matter of dis¬
persion. The construction of refracting telescopes
made rapid advancement in the workshop of Dollond,
whilst reflecting telescopes, in the hands first of Short,
but far more conspicuously, of Sir William Herschel,
were shown to be capable of making unimagined dis¬
coveries. The geometrical theory of optical instru¬
ments was also greatly improved; but all this led
to little increased knowledge concerning Light itself.
If we except the valuable though imperfect treatises
of Bouguer and Lambert on the subject of photo¬
metry, and a paper by Mr (now Lord) Brougham in
the last years of the century, recalling attention to
the inflexion of light, the history of Physical Optics
(as that part of the science touching more imme¬
diately the nature and qualities of light is now usu¬
ally termed) is almost a blank from the publication
of the Optics of Newton in 1704 to that of Young’s
papers almost one hundred years later.
It is not therefore from overlooking Young’s pre¬
decessors that we open our review of the recent pro¬
gress of optics with his discoveries. We here meet
with a man altogether beyond the common standard,
one in whom natural endowment and sedulous cul¬
tivation rivalled each other in the production of a
true philosopher; nor do we hesitate to state our
belief that since Newton, Thomas Young stands un¬
rivalled in the annals of British science.
He was born at Milverton in Somersetshire on the (446.)
13th June 1773, and his biographers dwell with com- His early
placency on the prodigies of his youth, uncertain as ^cutt0°
such attainments confessedly are in stamping thements '
greatness of the future character. At the age of
fourteen he had learned (principally for amusement)
seven languages besides his own, and besides had
made a point of mastering every subject, whether in
science or miscellaneous knowledge, which he had
once determined upon prosecuting. Thus, whilst
studying botany he resolved to learn how to make a
microscope, but finding in Martin’s Optics the nota¬
tion of fluxions, he became his own preceptor in that
branch of analysis. “ He acquired a great facility
in writing Latin. He composed Greek verses which
stood the test of the criticism of the first scholars of
the day, and read a good deal of the higher mathe¬
matics. His amusements were the studies of botany '
and zoology, and to entomology, in particular, he at
that time paid great attention.”3 Dr Young’s edu- >.
cation wras almost completely private. Having been
brought up according to the tenets of the Society of
Friends, he had not thought of going to Cambridge
1 See also Herschel on Sound (Encyc. Metrop.'); and Whewell’s History of the Inductive Sciences, vol. ii.
2 It may be mentioned, however, that the credit usually ascribed to Dollond must be divided, at least, with Mr Hall, a pri¬
vate gentleman of Worcestershire, who not only imagined but constructed achromatic telescopes as early as 1733 (Oentleman’s
Magazine, 1790, and Phil. Mag., vol. ii.) The improvement by Dr Blair of Edinburgh has been alluded to in Sir John Leslie’s
Dissertation. It consisted in enclosing fluids in the object glass, of such composition as to disperse the several rays of the spec¬
trum in the same proportion to one another (though not to the same absolute amount) as the glass with which it was combined ;
thus rendering the achromatism more perfect.
3 Memoir of the Life of Thomas Young, M.D. 8vo, 1831. The present section of the Dissertation was written shortly be¬
fore the publication of the Life and Miscellaneous Works of Dr Thomas Young, for which the public is indebted to Dr Peacock,
Dean of Ely, the possession of which would have materially facilitated my task. Wherever Dr Peacock’s information has
894
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
Residence
at Edin¬
burgh ;
(447.)
at Gottin¬
gen and at
Cam¬
bridge.
(448.)
Character
of his in¬
vestiga¬
tions.
(which would have been his natural destination^, and
entered the university of Edinburgh as a medical stu¬
dent at the age of twenty-one. He had already de¬
clined the overtures of such distinguished patrons as
Windham and Burke, resolving to devote himself to
the pursuit of science, for which a medical education
seemed to him a fit entrancehis studies being made
under the more immediate advice of his uncle, Dr
Broeklesby. He attended Black’s lectures in Edin¬
burgh ; whether he was known to Robison I am not
aware, though I should be inclined to infer that he
was from the terms in which Robison speaks of
Young when criticising his strictures upon Smith’s
Harmonics. Robison disagreed with him on this
point, and also about the nature of light, yet he
speaks of Young and of his paper on Sound with
very marked respect. More than a year before his
enrolment at Edinburgh (which took place in autumn
1794), he communicated to the Royal Society of
London a paper on vision, of which we shall pre¬
sently give some further account; and was elected a
fellow of the Society when just of age.
From Edinburgh he proceeded to Gottingen where
he graduated ; acquiring the German language, and
leaving a vivid impression of his astonishing versa¬
tility of tqlent and powers of memory. Early in
1797 he returned to England, and soon after en¬
tered himself at Emmanuel College, Cambridge, in
order to comply with the requisitions of the London
College of Physicians, and thus to obtain a license
to practice. For the next few years his time was
divided much between Cambridge and London. He
was now twenty-three years of age, and his mental
habits too much formed to bend to the rules of Cam¬
bridge study. When the master of his college intro¬
duced him to the fellows, he is reported to have said,
“ I have brought you a pupil qualified to read lec¬
tures to his tutors,” and such, no doubt, was the fact.
We hear little of his occupations at Cambridge, but
we can hardly doubt that his private studies then
ranged over the vast fields of erudition which he af¬
terwards proved that he had made so completely his
own ; and we cannot doubt that he was then preparing
the groundwork of his theory of optics, although his
discovery of interference was certainly not made at
Cambridge, and probably in London after his settle¬
ment there in 1800.1 His first paper on sound and
light is dated from Cambridge in July 1799.
I have entered into these details because they
throw light on the peculiarities of Young’s cha¬
racter and attainments. He was to a great degree
self-educated ; and his studies in consequence may
be called desultory, though none would dare to call
them superficial. Mathematicians may consider his
acquaintance with their science as not technically
complete, yet one of them admits that “ he could
make a small amount of mathematics go farther than
any one else.” Had he been a consummate analyst
it is unlikely that we should have had in him the
author of the undulatory theory, the difficulties of
which in its earlier stages made it unpalatable to
Laplace, Poisson, and the most considerable French
mathematicians. Having thought out for himself
every one of the multifarious subjects with which he
grappled, his writings have a striking force and ori¬
ginality, and his reports of the labours of others are
almost invariably drawn from a study of their original
works. His earliest principle was, that what one
man has done another may accomplish; and one of
the many respects in which he resembled his great
predecessor Newton, was unbounded confidence in
the powers of “ patient thought.” Not that he con¬
fined the desire to excel to purely intellectual matters.
What he found it worth while to do at all, he thought
it wTorth doing well. He chose to be first-rate in
dancing and in equitation;—his penmanship was (in
his early days) as scrupulously elegant as his scho¬
larship.
In 1801 Young was appointed Professor of Natu- (449 )
ral Philosophy at the Royal Institution, where he was \°e^esson
the colleague of Davy. Young had not the qualifi- Natural
cations of a popular lecturer, and the most important Philosophy.
result of his short connection of two years with the
Royal Institution was the publication in 1807 of his
Lectures on Natural Philosophy, in two large quarto
volumes. It is a work peculiarly characteristic of the
author; and is rather adapted for reference by the
scholar, than to be studied as an elementary trea¬
tise. Its condensation is such as to render it in
many places obscure; though when read by one
conversant with the subject, its comprehensiveness
and precision are surprising. It is a truly admi¬
rable monument of labour and genius combined.
Embracing the arts as well as the whole of natural
philosophy, it seems to include the mention of every¬
thing connected with his vast subject from the
simplest tool of the artisan to the highest specu¬
lations of Newton and Lagrange; and yet it is evi¬
dent, by the masterly manner in which he handles
it, that the author had made all this mass of know¬
ledge completely his own. The catalogue of refer¬
ences with which it closes indicates an extent of bib¬
liographical research which would have done honour
to any one who had made that an exclusive object of
study. Even the plates are drawn with a studious
care, betokening well his own mechanical talent.
enabled me to improve the text I have not hesitated to use it. The facility of consultation afforded by the collection of Dr
Young’s widely scattered writings is a most important aid to all future students of science, and one which cannot fail to raise
still higher the great reputation of their author.
1 See Sect. vii. of the article Polarization in this Encyclopaedia, where, in a bracketted interpolation by the translator.
Dr Young, he speaks of this fundamental experiment being made “ in the room and at the table on which he is now writing.
This must have been in Welbeck Street, London,
(450.)
(451.)
(452.)
The undu-
latory
theory of
light—
Hooke.
Chap. V., § 1.]
OPTICS.—YOUNG.
895
Many of tlie figures, though of hackneyed subjects, are
represented in a novel manner; there seems not a
line drawn at random. Such figures often illustrate
better than pages of description, the clearness with
which an author has conceived to himself the neces¬
sary results of his own principles. An example of
this may be found in Plate XXX., fig. 442 of the
first volume, which, as Arago relates, served to de¬
monstrate to him, when he visited Dr Young in
1816, that he and Fresnel had been anticipated on
one point more than they believed.1
The absence of algebraic formulae from this work
was as characteristic of Dr Young as their copious
introduction into articles which he subsequently con¬
tributed to the Quarterly Review. He had decided
upon writing a book without symbols, and he wrote
it, though it gave additional trouble both to himself
and the reader.
We shall now proceed to trace the progress of the
undulatory theory of light, the greatest physico-
mathematical discovery of our time, in the establish¬
ment of which Young acted the leading part.
Undulations of Light—Hooke and Huygens.—
The idea of accounting for the effects and modi¬
fications of luminous impressions by disturbances
propagated through a very elastic medium was by
no means new at the commencement of the present
century. We do not, indeed, attach much impor¬
tance to the so-called anticipations of Grimaldi and
Hooke in the seventeenth century. The former,
amongst his valuable experiments on the deflection of
light and fringes of shadows, had used an expression
as to illumination being diminished by the addition of
light, which is true in fact, and is a correct deduction
from the law of interference as we now understand it.
Hooke, in his Micrograyhia, asserts light to consist
in “ quick, short, vibrating motion but his expla¬
nation of refraction by it is altogether erroneous;
and his application of it to the doctrine of the colours
of thin plates, though admitted by the candid Young
to be an anticipation (unknown to him at the time)
of his own, has in it no more than a germ of truth
(like so many of Hooke’s ingenious hints, afterwards
claimed by him as discoveries), which yet only ex¬
plains the fact on which it is founded by means of
an additional and gratuitous assumption. The germ
of truth in Hooke’s writings is this, that the colours
in question depend upon a mixture of the light re¬
flected at the first surface of the thin plate with “ a
kind of fainter ray ” propagated from the second sur¬
face backwards: the gratuitous assumption is, that
“ this compound or duplicated pulse does produce on
the retina the sensation of a yellowwhy it does so
is not explained. This was in 16 64, before even New¬
ton was acquainted with the analysis of white light.
Hooke’s idea that yellow, or any other colour, was
the result of the conflict of pulses simultaneously
reaching the eye, was an assertion, admissible, per¬
haps, at that time, as expressing a fact; but surely
not a proof of interference producing reinforcement
or annihilation of light, as taught by Young. I am
not aware that Hooke ever even reiterated his opinions
on this subject after Newton had analysed the phe¬
nomena experimentally, and shown that the colours
of thin plates result from the superposition of bright
and dark rings of different prismatic hues, each with
its appropriate diameter. It was then apparent that
colour was only an indirect effect of interference.
But whatever may be thought of the theories of (453.)
Hooke, those of Huygens deserve a far more eminent IIuygens’
place in history. Having already been succinctly ad- '-LumAer-a ^
verted to in Professor Playfair’s dissertation, we will
only observe that the Traite de la Lumiere (1690) is
an admirably composed and reasoned treatise on the
phenomena of light on the undulatory hypothesis.
The uniformity of its propagation through the celes¬
tial spaces, its rectilinear course in ordinary circum¬
stances, the laws of its reflection and refraction, are
there explained with a degree of elegance and preci¬
sion which ought to have excited (we must think)
general attention and assent, but for the ascendancy
of Newton’s authority, and the astonishing and beau¬
tiful nature of the experiments on which his theories
were based; whereas Huygens referred to few expe¬
riments except those of the simplest kind, and the
phenomena of colour were (for good reasons) left
chiefly out of view.2 Such being the case, Huygens
may fairly be considered as the author of the undu¬
latory theory, which he supported by such convincing
proofs.
The fundamental principle of the Huygenian (454.)
doctrine was the same as that which Hooke ad- Explana-
mitted, which was probably far older than his time, t!on ,
namely, that all space, including the interior of double re¬
transparent bodies, contains an ether whose pulsa-fraction,
tions communicate the sense of light to the eye, as
waves in air convey to the ear impressions of sound.
To this he added the assumption, that in refracting
media, such as glass, the pulsations are retarded ;
whereas in Newton’s theory, as is well known, the
propagation of light is assumed to be fastest in dense
media. The “law of the sines” in refraction, is de¬
duced as a consequence ; and one of the prettiest ap¬
plications made of it is to the phenomena of atmo¬
spherical refraction. But the most important features
of the whole investigation are these two—(1), the
1 The reference of Arago, in his original eloge of Young, is to p. 387 of the Lectures, obviously by mistake. In the first
volume of his (Arago’s) collected works it is corrected into p. 787, which is as certainly correct. I have supposed fig. 442 to be
more probably the one referred to than 445, to which Dr Peacock refers {Life of Young, p. 389).
2 Nevertheless the Huygenian Theory of Light was propounded as the subject of a thesis at St Andrews by David Gregory,
whilst professor of mathematics there, within about a year of its publication (including also the Newtonian doctrine of gravity),
—a pleasing proof of the activity which then reigned in that university. Principal Lee possesses the original programme.
896
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
principle that the impression of a wave of light
on a screen is to be found by considering the simul¬
taneous effect of the wavelets propagated from all
the points disturbed at any previous moment (which
points form what is called the front of a wave).
It is only when these partial impressions concur
that they are strong enough to affect the sense of
vision; (2), the representation of the phenomenon of
double refraction by a wave of two sheets, or the
simultaneous propagation of spherical and spheroidal
waves in one and the same medium. Of the last of
these doctrines I shall speak in the next section in
connection with the discoveries of Malus. With re¬
spect to the former I may here observe that it gives
the only satisfactory explanation of the primary diffi¬
culty of the undulatory hypothesis,—namely, that a
beam of light admitted by a hole in a screen pursues
a rectilinear course afterwards, instead of spreading
sideways, as do waves in water, and waves of sound.
Huygens shows, on elementary and convincing prin¬
ciples, that the lateral impressions of the wave are
rapidly extinguished by the want of concurrence of
the impulses which they communicate to the ether.
This is necessarily true when the breadth of the aper¬
ture is such as to exceed vastly the length of a wave ;
and such is always the case with light, but rarely in
any other instance. It is, in short, only imme¬
diately in front of the aperture that the disturbances
originating in every part of the front of the original
wave embraced within the aperture, concur in pro¬
ducing an accordant movement on the ether.
(455.) This principle, more fully stated, by which every
The prin- luminiferous disturbance of the ether is considered
lluygms as resultant °f all the pre-existing disturbances
to which it is due, constitutes what is sometimes
called the principle of Huygens, of which I shall
have more to say hereafter.
(456.) Neither at the time of its publication, nor for
Newton’s more than a century afterwards, was the value of
the nature11 these reasonings understood. It would be beside
.of light. our present object to discuss Newton’s opinions; but
it is too certain that he did not allow Huygens’ argu¬
ments on the undulatory nature of light to have any
weight with him. Not that he was averse (as is
often supposed) to the presence of Ether as modify¬
ing the corpuscular theory of light; on the con¬
trary, in many of his minor writings he speaks of
its existence as all but certain, and as a requisite
adjunct to the corpuscular hypothesis to which he
had been led by the facts of reflection and refrac¬
tion.1 But he never adjusted the terms of a compro¬
mise, and must be held, we think, to have left behind
him no substantive theory of light worthy of the
name. The question never perhaps very seriously
engaged his attention after the publication of Huy¬
gens’ book ;2 and we know that about that time his
intellectual energies received a shock which left him
indisposed for the fatigue of constructing new theories,
and still more disinclined to publish them.
Euler, though he professed to defend an undula- (457.)
tory theory of light, treated the subject in a point of Euler,
view chiefly mathematical, and betrayed that uncon¬
cern about physical theories which characterized a
mind steeped in geometric abstractions. He even
retrograded ; for he did not maintain the Huygenian
explanation of the cause of detinite shadows.
Young on the Undulatory Theory—Diffraction. (458.)
—One hundred and ten years after the publication of Touns,°"
, A the undula-
the Traite de la Lumiere ot Huygens, Dr Thomas tory theory
Young re-opened the theory of light or “Physical Op—Diffrac-
tics,” as he termed it. His experiments and reasonings tion*
will be found in a series of papers in the Philoso¬
phical Transactions for 1800,1801,1802, and 1803.3
These memoirs are of no great length, and deserve
the most careful study. They are perhaps among the
clearest and plainest of Young’s writings, although
blamed at the time for defects precisely the reverse.
They are eminently marked by penetration, profound
induction, and candour of argument. Starting from
his studies in acoustics, the transition to optical
questions is extremely gradual. Young was, cha¬
racteristically, a good musician in practice, as well as
a profound one in theory, and his paper of 1799 is
principally acoustical. In it he attaches conse¬
quence to showing that the divergence of sound from
the direction of its emission is slower and less com¬
plete than it is commonly believed to be, and he applies
the analogy to the existence of rays of light and definite
shadows. In one short section he sums up the chief
points of optical doctrine which lead him to prefer
the theory of Huygens to that of Newton. Amongst
the facts better explained by waves than corpus¬
cles, we find reckoned Inflection and the Colours of
thin plates. But all this is stated in a very general
way, evidently rather as a conclusion towards which
his mind had for some time been tending, than as the
result of demonstrative proofs. In his paper of 1801
the undulatory doctrine is methodically expounded in
a series of propositions, accompanied by proofs. The
accurate definition of shadows is shown to be possible
and natural on that theory, as well as the usual phe¬
nomena of reflection, refraction, and total reflection.
1 Thus Newton writes in 1675 :—“ Were I to assume an hypothesis, it should be this, if propounded more generally, so as not
to determine what light is farther than that it is something or other capable of exciting vibrations in the ether ; for thus it will
become so general and comprehensive of other hypotheses as to leave little room for new ones to be invented.” And again,
“ Do not the most refrangible rays excite the shortest vibrations [of the retina], the least refrangible the largest ? ”—Birch’s Hist,
of the Royal Society, quoted in Young’s Lectures, ii. 615, 617. Sir D. Brewster (Life of Newton, 1855, vol. i. p. 148) considers
that some passages in the later editions of Newton’s OpJtcs show that he had departed from any theory of undulations.
2 The Optics, though published in 1704, had been written principally in 1675 and 1687 (see Preface).
3 They may be more conveniently consulted as reprinted in the second volume of his Lectures on Natural Philosophy, and in
his Miscellaneous Works, vol. i.
Chap. V., § 1.]
OPTICS.—YOUNG.
897
Optical
paradox.
(459.)
The Erio-
meter.
(460.)
Fundamen
tal law of
interfe¬
rence.
The partial reflection which always accompanies re¬
fraction is strongly and justly insisted on as an ob¬
vious consequence of the theory, while it requires a
sepai'ate hypothesis on Newton’s. But the chief
weight is claimed for the evidence from the colours
of heated surfaces, of thin plates, and of diffracted
shadows, all of which the author explains by the
mixture of two portions of light conveying to the
same particle of ether at the same time either ac¬
cordant or opposing motions, thus redoubling or
destroying the light. Of these the splendid iri¬
descent colours reflected by surfaces having fine
equidistant lines drawn upon them, admit of the
most elementary and striking explanation. The
reflected image of a luminous point viewed in a
mirror thus cut up by parallel lines, consists of one
common reflection and numerous lateral images
which are coloured, and in which the angles of inci¬
dence and reflection are not equal, thus contradicting
one of the axioms of common optics. Young showed
that the scattered waves of light recover the faculty of
appearing when the surface of the plate is seen under
such an angle that foreshortened intervals between
the scratches amount severally to the length of one
undulation or a multiple of it; for then the waves of
light scattered by the reflecting surface will not come
entire to the eye, but each will have a part systema¬
tically suppressed by the non-reflecting space of the
groove, so that the remainders being nearly in one
phase, concur in making a general impression. This
experiment, therefore, literally presents us with the
paradox that by suppressing half the light, the re¬
mainder is not suffered to be extinguished by it. The
different colours appear reflected at different angles,
because the obliquity must vary in order to be ac¬
commodated to their several wave-lengths, and each
colour undergoes several repetitions corresponding
to breadths representing the successive multiples of
a wave-length.
Precisely similar in their origin are the coloured
rays scattered by fibrous substances when held be¬
tween the eye and a small point of light. If they be
numerous and all of the same diameter, such fibres
will suppress symmetrically portions of waves, and
suffer the oblique effect to be perceptible. Dr Young
most ingeniously applied this principle to construct
an Eriometer or measurer of the fineness of fibres.
The diffracted light of any order and colour from a
distant flame will be seen at an angle with the prin¬
cipal or white image about four and a half times
greater when viewed through the down of the beaver,
than in the case of Southdown wool; being the in¬
verse proportion of the diameters of the fibres which
compose them.
Fundamental Law of Interference.—But the cri-
- tical and characteristic experiment of interference in
its simplest shape was published two years later, in
the Bakerian Lecture for 1803.1 A small hole
being made with a needle point in a piece of paper
applied to a window-shutter, and a sunbeam being
directed upon it by means of a mirror from with¬
out, a cone of light is thrown into a darkened room.
A slip of card one-thirtieth of an inch wide being
held in the sunbeam, its shadow was observed on
the opposite wall or on a moveable screen. There
were seen fringes of colour exterior to the shadow
on each side, such as Newton had described, and on
which Mr Brougham and others had made experi¬
ments. But besides these, the narrower and less
conspicuous fringes seen in the interior of the shadow,
and first described by Grimaldi, were found by Young
to have this remarkable property, that they disap¬
peared the moment that the light passing either edge
of the card was intercepted, whilst the exterior fringe
was not at all affected by that circumstance excepting
on the side where the light was stopped.
Young at once perceived the significance of this (461.)
admirable fact. The existence of light within the ^n^nds
shadow at all, was evidently due to the bending ofexpiained.
the wave round the opaque edge ; but the alternation
of light and dark spaces required the union of the
two lights from opposite edges, which, immediately
behind the centre of the obstacle, must have de¬
scribed exactly equal paths, and therefore united in
the same phase; but a little way either to the right
or left of the centre the phases were discordant, and
complete and effectual annihilation of the light re¬
sulted. In fact, when the experiment is performed
under favourable circumstances, the result of the
union of the light is perfect blackness in these places,
but if half the light is stopped the dark spaces be¬
come luminous !
This splendid paradox may also be demonstrated (402.)
without any bending round the edges of bodies, and Mixed
consequently without any inflexion in Newton’s sense
of the word ; and this simplifies the conditions mate- bands,
rially. In order to effect this, Fresnel (many years
after) produced interference bands by allowing light
emitted from a very small luminous point (an image
of the sun formed by a lens of short focus) to fall
upon two mirrors touching at the edge, and inclined
to one another at an angle very little less than 180°.
By the common principles of reflection there will be
a space beyond the mirrors where the light reflected
from the respective mirrors overlaps, and except in a
single line within that space, the paths of the two
rays meeting in any point will be different. When
this difference amounts to a whole number of undu¬
lations, an exalted brightness results ; when the un¬
dulations arrive in opposite phases or the centres of
one set of waves concur with the ends of the other,
blackness results. The experiment may even be
made with a single mirror which a ray of light just
grazes, and after reflection mixes with the direct light
1 Miscell. Works, vol. i. p. 179.
5 x
VOL. I.
898
mathematical and physical science.
[Diss. VI.
which had in the first instance passed clear of the
mirror.1 Here evidently we have the required con¬
dition of double illumination with difference of paths.
The same effect is obtained without either Inflexion
or Reflection by refraction through an excessively
flat prism.
(463.) It ^ an easy matter (comparatively) to assign the
Length of lengths of a wave of light, from the intervals of the
the waves interference lines, or still better from the elongations
of coloured ^ ^ coloure(j images produced by striated surfaces,
lg ' the intervals of the striae being given. Newton’s
measures of the intervals between the lenses pro¬
ducing coloured rays, gave Dr Young the following
for the number of undulations contained in an inch
producing each colour:
Extreme Red  37,640
Boundary Red and Orange  40,720
... Orange and Yellow  42,510
... Yellow and Green  45,600
... Green and Blue  49,320
... Blue and Indigo  52,910
Indigo and Violet  55,240
Extreme Violet  59,750
Now the velocity of light is known, that is, the rate
of propagation of a disturbance in ether; but the
duration of an impulse, or rather the interval between
two successive impulses striking the eye and pro¬
ducing the effect of colour, is the time that an impulse
Number of takes to travel over the length of a wave. It is easy
vibrations to see how almost infinitely short this must be : 460
in a second. mfffions of millions of such impressions in a second
of time go to make up the sensation of redness, 735
millions of millions that of violet light.
(464.) It might be supposed that Young’s discovery and
Opposition its application excited the notice and applause of all
to Young s persons interested in optics. This was very far from
V16WS* x •/
being the case. Though he brought it several times
in succession and in different forms before the Royal
Society of London, there is no evidence, so far as I at
present know, of his having then obtained a single ad¬
herent. Davy was no optician; Wollaston was too
cautious to commit himself, though probably giving
a tacit assent; Cavendish was aged, and besides had
attended less to this subject than to most others ; Sir
William Herschel had only lately taken up phy¬
sical optics, and that with reference to the qualities
of the spectrum least connected with Young’s obser¬
vations. At the Royal Institution Young vainly at¬
tempted, in the elaborate course of lectures which he
there delivered for two years (1801-3) on natural
philosophy and the arts, to arouse a popular inte¬
rest in the unveiling of these mysteries. The ab¬
struseness of his discourses scared that mixed audi¬
ence, and his colleague Davy, in a letter, incidentally
observes that Young would be satisfied if any one
would even offer criticisms on his opinions. Criticism
of a certain kind, however, he soon got in abundance.
The Edinburgh Review, in its second number, under¬
took to crush at once the theory of Young and his
reputation as a philosopher, and this (in singular
contrast to its avowed principles), not by argument,
but by an appeal to the weight of prescriptive autho¬
rity in favour of the Newtonian hypothesis, conclud¬
ing with an admonition to the Royal Society to cling
to its old standards and old celebrities, and to save
its Transactions from degenerating into volumes of
miscellanies. This attack, paltry as it was, seriously
prejudiced the reception, or even the dispassionate
consideration of Young’s views. His anxious vin¬
dication put forth in a separate pamphlet was unread,
and the doctrine of interference was first understood
and relished in France ten years later.
Theory of the Rainbow.—It is a matter of interest (465.)
in several points of view that the phenomenon of the ^he0I7 of
rainbow, which gave the first suspicion of the vary- bow incom.
ing refrangibility of light, and which, when explained piete with-
and reduced to calculation by Newton, so convin-out the
cingly proved the truth of the doctrine of the compo- f °tCg^fg.e
site nature of white light, was destined in the hands pence,
of Young and of his successors to yield one of the most
refined evidences of the extensive application of the
doctrine of interference. The general fact of the ar¬
rangement of colour in the primary and secondary
bows Newton accounted for. But the spurious or Spurious
supernumerary bows occasionally seen within the bows‘
primary, and far more rarely beyond the secondary,
consisting of reddish and greenish bands, remained
unexplained. The brilliancy of any given portion of
the rainbow depends upon the deviation of the sun’s
rays by two refractions and one reflection, approach¬
ing to a limit which it cannot overpass. But except at
this precise limit an amount of scattered light will
reach the eye, which, though not reflected under the
most favourable circumstances, yet is still sufficiently
intense to be visible. This light must be composed, as
Young showed, of two portions, entering the eye in
the same direction, but which have pursued different
paths within the drop, and which never coincide except
at the extreme geometrical limit before mentioned.
When one of these paths differs from the other by the
length of half a wave of the particular kind of light
considered, darkness will result, but a feebler maxi¬
mum will be again attained when the interval rises
to a whole wave-length, or to two or more. Hence
these consequences follow—first, that the bright part
of each colour is limited by its self-destruction to a
narrow band, and thus the purity of prismatic colour
so striking in a well-formed rainbow is preserved ;
secondly, that each colour may attain (by interference)
a second and a third maximum, corresponding in fact
to the position of the spurious bows; thirdly, that
these phenomena of perfect definition of the primary
and secondary bows, and of repeated maxima in the
supernumerary bows, depend essentially on this condi¬
tion, that the drops of falling rain shall approach to
1 This experiment is usually (and justly) ascribed to an eminent and amiable British philosopher. But it had already been
performed by Fresnel with a special object. See Ann. de Chimie et de Physique, second series, xv. 382.
Chap. V., § 1.]
OPTICS.—YOUNG.
899
a general equality of size. For the effects of inter¬
ference depend on the precise diameter of the drop ;
if these be very various the resulting positions of
maxima and minima will he altogether confused.
Dr Young pointed out that to accord with the phe¬
nomena the falling drops must be about Jg of an
inch in diameter.
y. O66-) I have merely indicated the nature of an argu-
the pheno- ment extreme interest and beauty. It would be diffi-
menon of cult to cite (except perhaps in the science of physical
the rain- astronomy) a more complete specimen of gradual in-
tesToT a ductive research. Here is a phenomenon—the rain-
Theory. ^)0W—as familiar as it is beautiful. Even a partial in¬
sight into its cause confers a certain reputation upon
one individual (De Dominis), its farther explication
gave Newton one of his most popular triumphs. It is
then found that the rainbow is not so simple a fact
as was supposed, and that Newton’s theory accounts
for only its broader features. Then, as in the theory
of gravity, a long period of uncertainty ensues ; hut
observations are continued. A perfect rainbow is
found to be one of the rarest of natural phenomena,
instead of the commonest. Not above two or three
individuals have ever seen, or at least described one.
Then comes Dr Young, with his theory of interfe¬
rence and diffraction. This theory not only accounts
for the spurious bows, but for the precise appearance
of the principal ones, which, but for it, would have
been different from what Newton supposed. Finally,
after being canvassed for more than two centuries,
the theory of Young is carried out into its rigorous
consequences by Mr Airy1 and Professor Stokes2
(who must first invent a new mathematical method
for the purpose) and illustrated by the ingenious ex¬
periments of M. Babinet and Professor Miller ;3 until
at last we begin to believe that we understand this
matter completely.
Exterio^ Exterior Fringes of Shadows.—I have men-
fringes of ti°necl only generally Young’s application of his
shadows; theory to the coloured fringes observed by Grimaldi
and Newton to surround the outline of bodies, as
thrown in shadow by a luminous point upon a dis¬
tant screen. I have done so because Young’s ex¬
planation wTas imperfect, not to say incorrect. But as
it would be inconvenient to discuss the subject here,
I shall briefly indicate its history and result. Dr
Young expresses himself more obscurely in his paper
of 1801 on this point than on any other, indicating
three possible explanations. In 1803, however, he
distinctly adopts the opinion that the periodical
colours in question are due to the interference of
direct light passing near the opaque edge with a por¬
tion of light very obliquely reflected from that edge;
and he enters into calculations to show that such a
theory represents sufficiently well Newton’s measures.
But it is unaccountable that Young should have been
satisfied with the belief that the screens employed
1 Camb. Trans., vol. vi. (1838.) 2 Ibid.,
should in every case have reflected an appreciable
quantity of light (or indeed any light at all) in the
required direction. It might be conceivable in the
case of a cylindrical wire or a cylindrical hair; but
how could a film of gold-leaf or a slip of paper re¬
ceiving the light on its broad side furnish such a de¬
gree of oblique illumination ? It is wonderful that
Young’s intuitive sense did not perceive that the por¬
tion of a luminiferous wave passing near an opaque
edge, is deficient on one side of the interfering wave¬
lets which are necessary to make the boundary of
the shadow definite, and to extinguish the laterally-
spreading light. In short, he did not allow to Huy¬
gens’ principle (see art. 455) the full breadth of its
application—a discovery made some years later by
Fresnel, who has the credit of first explaining these
exterior fringes.
That great philosopher (the worthy rival of Young (468.)
in this career of discovery) found the means of com- ful1. exPla*
puting, on strict geometrical principles, the sum total them'due
of the disturbance produced at any point of a screen to FresneJ.
by the whole effective portion of a luminiferous wave
partially stopped by an obstacle of a given form.
The principle of the calculation is simple enough.
The origin of the light being distant, the front of the
wave is considered as flat when it breaks against the
opaque body. Its front is then divided (in thought)
into small elementary portions, each of which is con¬
sidered as the source of a disturbance propagated as
from a new origin. The effect of each wavelet is cal¬
culated in terms of the co-ordinates of its origin, and
of the point where its effect is to be considered. The
sum of all these simultaneous effects is collected bv
integration, a process which unfortunately is only
rigorously possible in a limited number "of cases.
Some of these cases were solved with great ingenuity
by Fresnel, and compared with observation. The re¬
sult was extremely satisfactory. Yet it is curious to
observe that Young’s explanation, if it had had a
sufficient physical basis, leads to nearly similar re¬
sults. In the case of an indefinite opaque body with
a straight edge, the illumination precisely at the
boundary of the “geometrical” shadow is, on Fresnel’s
theory, one-fourth of what it would have been were
the body removed. Within this line the light dies away
gradually, having no maxima or minima. Without it.
a series of dark and light bands occur, which rapidly
blend into a uniform illumination. The same theory
leads to results as to the position of the interior bands
which are also somewhat different from the simpler
calculation of Young, and still more conformable to
experience. Amongst the most singular of these re¬
sults is this (which is perfectly confirmed by obser¬
vation), that the shadow of a small round opaque
body (as a spot of tin foil) is illuminated by a
speck of diffracted light at its centre precisely
as bright as if the disk were removed! How, after
vol. ix. (1850.) 3 Ihid'f vol> viit (1842.)
900
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
this, can we talk of light as moving in straight lines
only ]
(469.) We must now advert to the peculiar and disadvan-
Young's tageous manner in which Dr Young laid his faither
farther re- researches before the world. The optical papers in the
chiefly63 Philosophical Transactions, ending with 1803, were
anony- the last which he published connected with his theory
mous. in that work, although he continued to be Foreign Se¬
cretary until his death twenty-five years afterwards,
and although during all that time he never ceased to
extend and perfect his views on the subject of his predi¬
lection. The explanation of this paradox is to be found
principally in the strictness with which he interpreted
the allegiance which he owed to the medical profes¬
sion. He had determined to be a practical physician ;
his early principles of action prevented him from
doing anything by halves ; and all experience affirmed,
that to gain confidence as a physician in the metropolis
he must cultivate sparingly, and as it were by stealth,
the studies of abstract science and of philology in which
he delighted. Unquestionably he was also disgusted
by the absence of one single supporter amongst the
members of the great society referred to,—by the in¬
jurious petulance of the then popular critical journal,
—and by the impossibility under which he laboured
of communicating orally his knowledge to a general
audience in an interesting and acceptable manner.
The result of all this was the suppression of many of
his opinions, and the publication of others in so con¬
cealed and uninviting a form that they remained
for years nearly buried and unknown to men of
science. He contributed a series of articles on sub-
Hls articles jects connected with light to the Quarterly Review ;
in the and we may well smile at the abstruse and really ob-
Iteview^ scure dissertations on detached points of science—
often unmercifully loaded with algebra—thus inter¬
spersed with articles of popular criticism for the enter¬
tainment of the reading public. From some of these
papers we may readily gather the soreness which he
felt at the cold reception of his discoveries. Farther
and still more important original speculations were
contained in a series of anonymous papers (sixty-
three in number) on a vast variety of subjects, both in
science and philology, contributed to the Encyclopce-
and Ency- dia Britannica. It is not in a work such as this that
CJiritannica we usua^y look for the first publication of great and
original views : the articles being anonymous could
only very gradually attract notice by their intrinsic
merit; and the obscurity of some of those written by
Young rendered this difficult enough. But it is most
fortunate that he was induced thus to write : many of
his most original thoughts must have been lost but for
these concealed repositories. In the articles in the
Quarterly Review, for example, we watch with interest
the impression which contemporary discoveries made
upon his mind. The spheroidal wave of extraordinary
refraction is explained by unequal elasticity of the
crystal in different directions j1 the discovery of polar¬
ization by reflection is received with characteristic can¬
dour, as giving a temporary blow to the undulatory
theory ;2 whilst in a later paper the cause of chromatic
polarization is convincingly deduced from the prin¬
ciple of interferences, and in the space of two lines
the peculiar coloured laminae occurring in Iceland
spar, which had been noticed by several experi¬
menters, are accounted for.3
From about 1815 the optical discoveries of Young (470.)
were so intimately connected with those of his younger Tlieoi7 °t
friend and rival Fresnel, that it seems best to defer de-
our account of them until we consider (in § 3 of this ferred to
chapter) the peculiar researches of Fresnel, which § 3>
ultimately rendered the phenomena of polarization
the most impregnable position of the partizans of the
undulatory theory. The first great step was the con¬
ception of transversevibrations of ether, as constituting
polarization. This, as we shall see, was first pub¬
lished by Young. It is to be regretted that the tardy
and imperfect publication of Fresnel’s memoirs on
the one hand, and the resolution of Young to adhere
to an anonymous and indirect mode of announcing
his discoveries, on the other, render the history of
the subject sometimes obscure. The correspondence
between them, first fully published by Dr Peacock,
throws some light upon it; but several important
letters have not been recovered.
I had intended devoting a portion of this section to (471.)
Dr Young’s important and ingenious researches on the Physiology
physiology of vision. But the length to which it has al- of vision ’
ready extended obliges me reluctantly to omit it. I also
refer to the chapter on mechanics (Art. 344, &c.) for
some notice of his masterly reasonings on the princi¬
ples of carpentry and the flexure of elastic substances.
They are characterized by directness of purpose and
a consummate command of ordinary mathematics,
unaccompanied by any pretension to symbolical dis¬
play ;—it might be added too, by the obscure concise¬
ness of Dr Young’s habitual style. His researches (pre¬
ceding and anticipating those of Laplace) on capillary
attraction have also been referred to (432), as well as
his masterly investigation of the tides (80, 81). It interpre¬
does not belong to this treatise to speak of his disco- j^ogiy-
very of the interpretation of hieroglyphics in certain pijics-
cases which gave the first real impulse to this obscure
but interesting subject. The successes of Champollion,
Rawlinson, and others, in similar undertakings, must
logically be connected with the first great step of de¬
cyphering the polyglot stone of Rosetta. It may safely
be affirmed that no philologer ever before made such
a discovery in science as the law of interference, and
that no natural philosopher ever made such a step
in the interpretation of a lost tongue as the forma¬
tion (up to a certain point) of an Egyptian alphabet.
We cannot close this imperfect sketch of one of (472.)
the greatest ornaments of our age and nation, without
1 Quart. Rev., vol. ii.
2 Ibid., vol. iii.
3 Ibid., vol. xi.
Chap. V.; § 2.]
OPTICS.—MALUS.
901
Young’s adding, that in private life Dr Young was exemplary;
personal ^ endued with warm affections, philosophic moderation,
character, high moral and religious principles. His office
as secretary to the Board of Longitude (the only
public promotion he received), was attended not only
with immense labour in editing the Nautical Al¬
manac, but with vexatious contentions, which in his,
as in so many other cases, tended to diminish his
usefulness and even shorten his life. To the petty
persecutions with which he was assailed, it was owing
that the health which the unbroken study of fifty
years had not impaired, at length gave way, and he
and death, died yet in the prime of intellect, the 10th May
1829, within a few months of his honoured asso¬
ciates and friends, Wollaston and Davy. He had
been elected two years previously one of the eight
foreign associates of the Academy of Sciences of
Paris.
Dr Young’s philosophical character approached in (473.)
many important particulars to that of Newton. With Philosophi-
much of the inventive fire of Davy, and of the rea- CharaC
soiling sagacity of Wollaston, he combined an amount
of acquired learning, and a versatility in its applica¬
tion, far superior to both. We do not ascribe to him
an intuitive insight so rapid and almost divine as
that which distinguished the author of the Principia
above all other men, nor had Young the same strictly
mathematical ability; but like Newton, whatever he
did was practical and sound ; nothing was done for
show, nothing omitted through haste. “ The power
of patient thought” was the lever with which he
moved the world. His self-confidence was great but
unobtrusive. He attained, as he himself said, all the
main objects to which he had looked forward in life,
“ such fame as he valued, and such acquirements as
he might think to deserve it.”
(474.)
Malus—the
polariza¬
tion of
light.
(475.)
Early his¬
tory of
double re¬
fraction—
Huygens’
law.
§ 2. Malus.—Discovery of the Polarization of Light by Reflection.—Early History of Double
Refraction and Polarization.
Etienne Louis Malus was born at Paris on the
23d July 1775, and died on the 24th February 1812,
after a too brief but brilliant career. His principal
discovery, that of the polarization of light by reflec¬
tion, is so intimately connected, both histoiically and
by the nature of the case, with double refraction, that
I shall briefly sum up the scanty progress of that
singular subject previous to his time.
It was known to Bartholin of Copenhagen, about
1669, that Iceland or calcareous-spar has the pro¬
perty of dividing a ray of light, which falls upon it
in almost any direction, into two; one of which is
refracted according to the usual law, but the other
in an extraordinary manner, which was first analyzed
by Huygens—a problem of great difficulty, in which
Newton not only failed, but he also erred in con¬
tinuing to pronounce Huygens’ solution false. The
solution was this, that there is one direction in the
crystal parallel to which both the rays (called the
ordinary and the extraordinary') move in a similar
and uniform manner. In other directions their pro¬
pagation may be expressed by considering the ordi¬
nary ray within the crystal to be due to a spherical
wave (the centre of which coincides with the point
of incidence), whilst the extraordinary ray corre¬
sponds to a flattened spheroidal wave concentric with
the former, and having its axis coincident with a
diameter of the sphere, and parallel to the minera-
logical axis of the crystal. Both rays, on the Huy-
genian hypothesis, move slower than in air, but the
extraordinary ray everywhere faster than the ordi¬
nary ray, excepting only in the axial direction. A
perfectly plain though necessarily complex construc¬
tion was given by Huygens for the purpose of tracing
both rays in the course of their refraction, founded
on this idea.
Newton’s opposition to Huygens’ law as a state- DTA)
ment of fact left it for more than a century under ^y^ollas-
partial doubt. Haiiy is stated to have verified it, or ton;
at least to have shown that it approached nearer to
the truth than Newton’s ; but Dr Wollaston first re¬
established it in 1802 by conclusive experiments,
which, however, he found it impossible to connect by
a law until the previous generalization of Huygens
had been pointed out to him,—most probably by Dr
Young.
It was several years later that Malus directed his (477.)
attention to the subject, unaware of what had been
accomplished by Wollaston. He had returned in
1801 from the unfortunate French expedition to
Egypt, where he was engaged as an officer of en¬
gineers, and had ruined his health through fatigue
and the insalubrity of the climate. He was an ac¬
complished mathematician, having acted as professor
both at the Polytechnic School and that of Metz,
and was of course a member of the Institute of Cairo.
On his return to France, during the intervals of his
military duties, he occupied himself in the composi¬
tion of an elaborate analytical treatise on optics, which
had already occupied his attention in Egypt. This
led him to the subject of double refraction, and he
verified by numerous experiments the accuracy of
Huygens’ law. La Place wrote a paper on the mathe¬
matical law of the velocity of the extraordinary ray,
in which he introduced the idea of a repulsive force
emanating from the axis of the crystal; but it may
be truly affirmed that the notion of a spheroidal un¬
dulation so happily introduced by Huygens is the
only one which really fits the case; and by the very
impossibility of expressing the facts intelligibly with¬
out it, gives an undisputed advantage to that theory.
A prize having been proposed by the Academy of (478.)
902
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
Essay on Sciences for the theory of double refraction, Malus
double re- wr0^e a second paper, which was crowned, but which,
however admirable as a specimen of mathematical
address, added little to what was previously known.
(479.) Malus had already, in the end of 1808, announced
Huygens’ a property of light which, if not absolutely new, was
so with reference to the circumstances in
tionby'calcwhich it was produced. The polarization of light
spar. was in reality discovered by Huygens previous to
1680. He had observed that the two rays into which
common light is divided in passing through Iceland
spar have a singular diversity of character, which
Newton afterwards described as an opposite polarity.
Huygens showed that if two rhombs of doubly re¬
fracting spar are laid symmetrically one upon the
other, the “ extraordinary” ray yielded by the first is
extraordinarily refracted by the second, and the “ordi¬
nary” ray from the first is ordinarily refracted by the
second. But when we revolve the upper rhomb
as it lies upon the lower one through a right angle,
a remarkable change appears. The extraordinary
ray escaping from the first is now ordinarily re¬
fracted by the second, and vice versa, so that the
qualities of the two rays differ but only so far as this,
that either may be assimilated to the other by making
it (or the crystal from which it derives its properties)
revolve round ninety degrees. A definite notion of
such a distinction may be formed by imagining a
musical string vibrating at one time in a vertical, at
another in a horizontal, plane. If we could possibly
imagine light to consist of vibrations of this descrip¬
tion, the two rays of Iceland spar might be conceived
the one to vibrate in a plane passing through the
axis of the crystal, the other in a plane perpendicular
to that. Such light might truly be said to have ac¬
quired the property of having sides. In the language
of Newton, it is 'polarized.
(480.) The discovery of Malus consisted in showing that
Malus dis- light may acquire properties identical with those of
larization c^er raJ yielded by refraction through Iceland spar,
by reflec- by the very simple process of simple reflection at a par-
tion- ticular angle from any transparent body. Thus for a
surface of water he found this angle to be 52° 45' with
the perpendicular, and for glass 54° 35'. The reflected
light in either case has exactly the property of the or¬
dinary ray transmitted by a crystal whose principal sec¬
tion (that is, a section passing through the axis of the
crystal) is parallel to the plane of reflection. Con¬
sequently this light will be acted on by a doubly re¬
fracting crystal placed in its way precisely as if it
had emerged from a similar crystal; and, on the
other hand, if the two rays emerging from a crystal
be incident on water or glass as above mentioned, the
one will be copiously reflected from the surface, whilst
the other will not be reflected at all, but pass entirely
into the transparent substance. Farther, as might
be expected, light thus polarized by reflection, when
it falls on a second similar reflecting surface at the
same angle as before, will be copiously reflected if the
planes of reflection coincide, but will refuse to be
reflected in an appreciable degree when the planes of
reflection are perpendicular.
This phenomenon was detected by Malus by casually (481.)
observing that a ray from the setting sun reflected Occasion
from a distant window, and viewed through a pieceof lt‘
of Iceland spar, afforded but a single image in two
positions of the latter. The experiment attracted uni¬
versal attention, and became the germ of a series of
optical discoveries almost unprecedented for their
beauty and variety; yet most of the experiments may
be made quite as well when light is polarized by the
method of Huygens as by that of Malus. Neverthe¬
less the former had remained a sterile fact for 130
years. Upon such trifling circumstances does the
progress of knowledge often depend.
Malus survived his discovery only four years, and (432.)
saw but the borders of that land of promise which heLawof the
had pointed out to others. A few results he however C0Slnes•
obtained, which are worthy of notice. Thus he found
that in every instance where light is polarized in any
plane there is also produced a certain proportional
amount of light polarized in the perpendicular plane.
Arago afterwards proved the very important fact, that
these two portions are universally equal. Huygens
had shown in the experiment of the two rhombs, that
wdien their positions are neither symmetrical nor
perpendicular, each ray emerging from the first is
duplicated by the second. When the principal sec¬
tions of the rhombs are inclined 45°, the duplicated
rays are equally bright; as they approach parallelism
or perpendicularity, one pair of the rays brighten and
the other pair is enfeebled. Malus ascertained the
law of change of brightness, which is the same for
rhombs of spar or for plates of glass whose planes
of reflection vary whilst the angle of reflection re¬
mains constant. In either case the intensity of the
light varies as the square of the cosine of the angle
formed by the principal sections of the crystals or
the planes of reflection of the plates. This impor¬
tant law, the best established in photometry, has been
applied by Arago to the measurement of light in
many instances, but the details were unfortunately
not made public before his decease.
To Malus is also due the discovery of the polariza- (483.)
tion of light by common refraction. When light is in- 0ther dis*
cident on glass or water, the refracted beam contains
precisely as much polarized light as the reflected beam,
but oppositely polarized. The metals were at first
believed by Malus to polarize no appreciable quan¬
tity of light. He afterwards found that at great in¬
cidences the reflected light is partly polarized.1 He
likewise ascertained the fact of the “depolarization” (as
it was termed) of light by many crystals, and also by
organized substances, such as hair, horn, and whale-
1 See an interesting letter from Malus to Dr Young in Thomson’s Annals, vol. iii.
Chap. V., § 3.]
OPTICS.
■FRESNEL.
903
(484.)
bone. He does not appear to have noticed the phe¬
nomena of colour accompanying such depolarization,
though he arrived at it so nearly that Arago, in all pro¬
bability, anticipated him by presenting a memoir on
the subject to the Institute just one week previous to
Malus’s announcement of what he had observed
(19th August 1811). In less than six months later
Malus was no more.
The writings and discoveries of Malus present evi¬
dence of great talent, but of far less fertility of com- Character
bination than those of Fresnel, presently to be no- of Malus.
ticed. He maintained the Newtonian theory of light.
His reputation amongst his intimates was extremely
high, and it was generally believed, that had he sur¬
vived, his discoveries would have extended much far¬
ther. To him was applied Newton’s saying on the
death of Cotes,—“ If Cotes had lived we should have
learned something.”
§ 3. Fresnel.—The Undulatory Theory of Light continued.—Diffraction.—Transverse Vibra¬
tions ; Young.—Polarization and Double Refraction explained.—Lighthouse Illumination.
(485.) Augustin Fresnel was born at Broglie, in France,
resne . iQth May 1788, of a feeble constitution, and he con¬
tinued throughout his too short life a prey to attacks
of bad health. As a boy, his slow apprehension and
uncertain memory gave no indication of the maturity
of his judgment. He entered first the Polytechnic
School, then that of Fonts et Chaussees. His fidelity
to the Bourbon cause occasioned his being harshly
treated by Napoleon, and he retired to Normandy in
the beginning of 1815, to pursue the scientific studies
which he had always loved.
Diffraction Diffraction.—The theory of light in particular at-
of light, tracted his attention, and he had a steady belief that
the Newtonian doctrine was erroneous, though in
ignorance, as it appears, of the undulatory doctrines
of Hooke, Huygens, and Young. The phenomena
of diffraction, or the coloured fringes which are seen
in the interior of the shadows of opake bodies when
illuminated by a minute source of light, attracted
his attention as most proper for deciding the deli¬
cate question of the molecular or undulatory cha-
Presnel’s racter of light. The results of his experiments were
moii,me" detailed in a memoir confided in the first place to
his friend Arago, and by him communicated to the
Institute of France (October 1815). This remark¬
able paper contained much which Dr Young had al¬
ready discovered, and the explanations of the experi¬
ments which it described, both new and old, by the
theory of undulations, were common to both. Dr
Young having anticipated the publication by at least
a dozen years, there could be no question of pri¬
ority ; but it is equally certain that Fresnel was un¬
aware of what Young had done until it was pointed
out to him by Arago. His memoir, which was pub¬
lished in great part in the Annales de Chimie for
1816, contains much which is interesting. The mode
of observing the diffraction bands directly by means
of a lens, without the intervention of a screen, was
equally new and important. The observation that
the interior fringes of the shadow of a narrow body,
such as a wire, disappear when the light is intercepted
on either side of the wire, leading to the conclusion
that the union of the light from both sides is neces¬
sary for their occurrence, was (as we have seen)
one of Young’s capital experiments. The explana¬
tion of Newton’s rings, by the interference of the light
reflected from two adjacent surfaces, though partly
anticipated by Hooke, was equally important. Nu¬
merous measures of the distances of the exterior
diffraction bands from the geometrical shadow, as
formed by homogeneous red light, are then given and
compared with theory. Here Fresnel was on original
ground. These accurate numerical comparisons, af¬
terwards pursued to a greater extent, constituted one
of the most important bases of the new theory. In
obtaining them he was materially aided by Arago,
who, though considerably his senior, generously as¬
sisted him in every respect, and gave him the full ad¬
vantage of his station as a member of the Institute,
and of his experience.
Fresnel’s first memoir on diffraction justly excited (487.)
so much notice that the subject was proposed by the ®econ<i h16-
Academy of Sciences in 1817 for one of their prizes, proves
The new essay which Fresnel then wrote was, as pro- upon
bably had been anticipated, the successful one. In Young’s
this memoir he made an important step, by showing theory*
that the exterior fringes in diffraction shadows do not
depend (as Young had supposed) upon the interfer¬
ence of the direct light with that reflected at a great
obliquity from the edge of the diffracting body, but
from the interference of the different elementary un¬
dulations which proceed from the disturbed surface
forming the front of the grand wave. Decomposing
the front of the wave into small portions after the
manner of Huygens, he computed the disturbance
produced by the integral effect of the whole at a given
point of the screen where the picture of the shadow
fell and was submitted to examination, and he fouud
that such integral effects have a periodic character,
presenting points of maximum and minimum distur¬
bance, or of greatest and least illumination as we re¬
cede from the geometrical shadow. These distances
being measured in homogeneous red light were found
to agree with the results of an arduous computation,
requiring, as will easily be seen, an intimate acquain¬
tance with the integral calculus and much skill in
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(488.)
Transverse
vibrations
—Young
and Fres¬
nel.
904
using it. Such Fresnel possessed, though he always
refers with great modesty to his limited facility of em¬
ploying the higher mathematics.
Transverse Vibrations— Young and Fresnel. —
Considerable obscurity hangs over the first publi¬
cation of this important discovery. A clear and
impartial abstract of the facts will be found in
the second volume of Dr WhewelTs History of the
Inductive Sciences, and some further documentary
evidence, including interesting letters which passed
between Young and Fresnel, have more recently
been published in the Life and Works of the for¬
mer, edited by Dr Peacock. The difficulty of appor¬
tioning the credit between Young and Fresnel partly
arises from the unfortunate system of imperfect pub¬
lication, or non-publication, adopted on professional
grounds by the former, and partly from the grievous
delays imposed upon the latter by the opposition with
which his opinions and experiments were received at
the French Academy of Sciences. This continued to
the very close of Fresnel’s career. His gi’eatest work
was not published in the Memoirs of the Institute
until six years after date; another was mislaid for
above twenty years, and even the hardy friendship of
Arago sometimes almost recoiled before the storm of
opposition which the novelties of his associate were
sure to excite in the minds of the dominant mathe¬
matical section. It is quite impossible to say pre¬
cisely at what period Young first imagined that the
differences of oppositely polarized rays of light might
be explained by perpendicularity in the directions of
vibration of the ethereal molecules, which he compared
to the vibrations of a cord in which the elementary
movements are at right angles to the direction of wave-
propagation. It seems evident that Young was not
possessed of this idea in 1814, when he partly explained
depolarization in a few pages of an article in the
Quarterly Review. It is equally certain that he an¬
nounced it to Arago (with whom he became person¬
ally acquainted in 1816) in January, 1817; and that
he then speaks of it as an idea which apparently had
recently occurred to him, most probably since their
interview.1 Arago and Fresnel had already, in 1816,
made experiments demonstrating that rays oppositely
polarized do not produce dark bands by their inter¬
ference, a memorable discovery, requiring very great
nicety for its satisfactory proof, which, however,
was completely attained. It was this observa¬
tion which (naturally) gave Fresnel the first idea
of transverse vibrations, and it is much more than
probable that Young worked out a similar solution
of the great problem, in consequence of the account
of these experiments which he received from Arago
in the summer of 1816.2 Be this as it may, Young
and Fresnel unquestionably imagined the theory se¬
parately, but Young first announced it, Fresnel being
discouraged by the doubts of Arago, and by his
awe of the Institute. As clearly, the experiment of
non-interference was the first which gave a colour to
so bold an assumption, and in the details of its ap¬
plication to double refraction Fresnel had the undi¬
vided merit. What is not least worthy of notice in
the affair, is that neither of the amiable rivals (Young
and Fresnel) ever published a word in disparagement
of the other, nor a single unfriendly reclamation of
priority.
The doctrine of transverse vibrations being allowed, (489.)
its applications and severest tests were twofold, 1st,
To the phenomena of ordinary reflection and refrac- of J
tion including the polarization produced by these ope¬
rations; and 2dly,to double refraction and the univer¬
sally concomitant polarization. In these bold specu¬
lations and laborious inductions, Fresnel was nearly
alone. Young did not appear as a competitor; even
his friend Arago, though sympathizing with and
proud of his success, was not associated with him.
Laws of Reflection and Refraction.—With re- (490.)
gard to the reflection and refraction of light, its in-
tensity has to be defined, and also its condition as to an(i refrac-
polarization. The fundamental laws of the direction tion—
of the rays are not affected by this theory. Rigorous 1 resnel-
mathematicians who then doubted the possibility
of transverse vibrations having more than a transi¬
tory existence, if they existed at all, could not be ex¬
pected to supply the theory of their reflection and re¬
fraction at the bounding surfaces of different media.
Fresnel, however, guided by probable mechanical
analogies, with an intuitive insight worthy of Newton
himself, gave a formula for the intensity of reflected
transverse vibrations, both when the plane of vibration
of the molecules is in the plane of reflection, and when
it is perpendicular to it; and he conceived common
light to act as if equally composed of both sets of
vibrations. His formulae embrace the non-reflection
of polarized light at the critical angle, under the
circumstances explained in the last section. It is a
most remarkable fact that these inferences by Fresnel
as to the numerical relations of the intensity of the re¬
flected to the incident light through all angles of inci¬
dence, anticipated almost every trustworthy photo-
metrical measure; and from their singular though
indirect accordance with many phenomena, they have
been generally accepted as an expression of a natural
law of great complexity, even by those who were not
favourable to the theoretical views on which they are
based. .
The modifications of the state of polarization of
light which takes place by reflection, was equally
1 “ I have also been reflecting on the possibility of giving an imperfect explanation of the affection of light which constitutes
polarization, without departing from the genuine doctrine of undulation.” He then refers to “ a transverse vibration propagated
in the direction of the radius, the motion of the particles being in a certain constant direction with respect to that radius; and
this,” he adds, “ is a polarization.”—Young’s Miscell. Works, vol. i., p. 383.
2 Peacock’s Life of Young, p. 390.
Circular
polariza¬
tion.
(492.)
Double re¬
fraction ex¬
plained.
Chap. V., § 3.] OPTICS —
embraced in Fresnel’s theory, and equally (though
unknowingly) confirmed by Sir D. Brewster’s labo¬
rious observations. But on one point Fresnel him¬
self obtained a signal triumph. Having deduced ex¬
pressions for the intensity of refracted light, on push¬
ing them to the limit where refraction out of a denser
into a rarer medium becomes impracticable because
the light undergoes total internal reflection, the for¬
mulae became affected by the multiplier and
were unsusceptible of arithmetical evaluation. In
endeavouring to attach a meaning to these expres¬
sions. it occurred to him that as the intensity of the
totally reflected ray undergoes no change with the
angle of incidence, the expression in question might
in some way determine the alteration of the phase of
the wave (the position and direction of motion of the
molecules under consideration) which took place at the
instant of reflection. Now, admitting this as likely,
it appeared that the phase would vary not only with
the angle of internal reflection, but with the plane of
polarization of the ray. It had previously been
shown by Arago and by himself, that when two oppo¬
sitely polarized rays meet or interfere, though there
is then no destruction of the light, there is usually
a remarkable change in its character. There is
one position of the interfering wave relative to the
primary one in which the combination produces light
polarized in a plane exactly intermediate between the
planes of previous polarization. If either ray be now
accelerated by half a wave-length on the other, the
new plane of polarization becomes perpendicular to
the former ; but if the shift of either of the primary
rays amounts to only one quarter of a wave-length,
the motion of the molecules takes place in a circle,
and the undulation has a helical form. Now, Fresnel
tested his hypothesis concerning totally reflected light
by calculating the circumstances of incidence which
should produce an effect equivalent to this ; and the
result completely verified his bold conjecture. The
apparatus employed is called Fresnel's Rhomb, which
transforms plane-polarized light into light equally
reflexible in all azimuths, yet not common light, be¬
cause it possesses properties which common light does
not (such as displaying the rings in crystals); this
is termed circularly polarized light.
Theory of Double Refraction.—The difficulty of
accounting for double refraction did not consist
in showing how a spheroidal wave might be pro¬
pagated. Young had already shown, in 1809, that
it would result from supposing a lamellar arrange¬
ment of the crystalline molecules so that the ether
was differently elastic in a direction parallel to the
axis than in a plane or planes perpendicular to
that line.1 Huygens had shown something similar
in accounting for terrestrial atmospheric refraction.
The difficulty was, to account for two waves travel-
■FRESNEL. 905
ling at the same time through the same portion of
matter with unequal velocities. The moment that
the idea of molecular movement transverse to the line
of propagation was admitted, it was easy to see that
no contradiction was involved in the idea. Two
waves might simultaneously travel in the same direc¬
tion, and through the same medium, provided the
molecular displacements were in different planes. So
happy a solution could hardly fail to strike such minds
as those of Young and Fresnel with the impress of
conviction. A closer analysis confirmed the proba¬
bility. Iceland spar (or rather the ether imprisoned
within it) is conceived of as a medium of uniform elas¬
ticity in all planes perpendicular to the axis, but of a
different and greater elasticity in any direction parallel
to the axis. It is shown to result from this, that in
the direction of the axis alone is the motion of light
independent of the plane of the vibrations of which it
is composed, and consequently no separation of rays
occurs. When a ray moves parallel to what may by
an analogy be called the equatoreal plane of the
crystal, its undulation will, generally speaking, be
resolved into two whose vibrations are parallel and
perpendicular to that plane, and which travel with
different velocities though in the same direction. If
the ray take any other direction through the crystal,
both the direction and velocity of the divided rays
differ. The form of the extraordinary wave is exactly
the spheroid of Huygens.
But what are wre to conclude concerning those crys- (493.)
tals (of the discovery of which we shall speak in § 5)Theory of
presenting two axes of double refraction ? Fresnel at^^!^
once assumed that the elasticities must in that case axes,
vary in three rectangular directions, and he proceeded
to calculate the manner of propagation of a wave
through a medium thus constituted. I had proposed
to attempt some explanation of the steps of his most
ingenious and profound argument, but I find it incom¬
patible with the space at my disposal, and at any
rate hardly to be apprehended without the use of
symbols or figures. For these reasons I shall merely
state the results. When the medium presents un¬
equal elasticities in three rectangular directions, the
surface of the wave consists of two sheets each tra¬
velling with its peculiar velocity. But neither of
these being spherical, the result cannot be expressed
by the ordinary law of refraction. In tivo directions
within the crystal, the wave surfaces coincide, or the
two rays coalesce. These directions are evidently
the optic axes, and the w^ave surface in their neigh¬
bourhood has very interesting geometrical and
physical properties which have been elucidated
by British philosophers, as will be noticed in
another section. The true optical axes cannot
exceed two, and when two of the three elasticities
become equal, they merge into one. This is the
1 Young’s reasoning (Quarterb/ Review 1809, and Works, vol. i. p. 228) is based on an experiment by Chladni on the differing
velocity with which sound is propagated in wood, depending on the direction of the fibres.
VOL. I 5 Y
(494.)
confirmed
by experi¬
ment.
(495.)
Reception
of Fresnel’s
theory;
in France,
in Eng¬
land.
006 MATHEMATICAL AND PHYSICAL SCIENCE. [Diss. YI.
case in Iceland spar and similar crystals. At Fresnel were first most generally and liberally ac-
the same time the wave surface degenerates into knowledged; as, singularly enough, Young had re-
the united sphere and spheroid. The equation to ceived almost the first expression of sympathy m his
the wave surface was deduced by Fresnel in an in- optical discoveries from France. In 1825 Fresnel
direct and somewhat tentative manner. It was received the distinguished honour of being elected
demonstrated by Ampere directly, but inelegantly, a foreign member of the Royal Society of London, only
M. Cauchy, Mr Archibald Smith, and Professors two years subsequent to his election into the Insti-
Sir W R Hamilton and Maccullagh gave more tute, and whilst his greatest paper was as yet known
complete and elegant solutions. only by an abstract. In 1827 he received the Rum-
Fresnel submitted his theory (as usual) to experi- ford medal from the same body. This recognition of
ment. He found that in topaz, which is a biaxial his merits was due, as we learn on the authority of
crystal, neither ray follows the law of common re- Dr Young (who was then Foreign Secretary of the
fraction. The plane of polarization (which is always Royal Society) to the influence of Sir John Herschel,
perpendicular in the two rays) follows very nearly at that time and afterwards a zealous supporter of
indeed, by theory, the law which M. Biot had as- the undulatory theory of light, and by whom it be-
signed by experiment. Fresnel thus stated the came first generally known in England through the
ground of bis conviction of the truth of his theory, medium of his admirable Essay on Light. . Dr
and it would be difficult to express more appropri- Young, though present, was silent;, fiom being,
ately the characteristics of a just hypothesis :— as he himself tells us, 4£ too much interested.in the
li The theory which we have adopted, and the simple subject ” on account of his personal share in the
construction which we have deduced from it, present matter. In announcing this distinction officially to
this remarkable character, that all the unknown Fresnel (then in the last stage of consumption,,
quantities are at once determined by the solution ol Young characteristically observed, I too should
the problem;—the velocity of the ordinary and ex- claim some right to participate in the compliment
traordinary rays, and their respective planes of polar- which is tacitly paid to myself in common v ith ) ou
ization. Physicists who have studied with attention by this adjudication ; but considering that more
the laws of nature, will admit that this simplicity than a quarter of a century is past since my prin-
and these intimate relations between different parts cipal experiments were made, I can only feel it a
of the same phenomenon present a great probability in sort of anticipation of 'posthumous fame which I have
favour of the theory by which they are established.” never particularly coveted.”"
The memoir on double refraction was received
with much incredulity and partial applause. It was I have stated in the opening of the section that (496.)
’ not to be supposed that a theory in opposition to Fresnel, who was attached to the Bourbon cause, had of
that imagined by Newton, and received with almost retired to Normandy near the close of Napoleon s ijghthcmse
general assent for more than a century and a half, career. On the re-establishment of the monarchy in illumina-
would not meet with many opponents ; but in the 1815 he was recalled from his retreat and appointed in¬
case of double refraction and polarization it was also to an office in the departments connected with his pro-
essentially coupled with the idea of transverse vibra- fession as an engineer ; but in 1817 he was brought
tions, whose exact mechanism was admitted on all to Paris with the express view of giving him more
hands to be extremely obscure. Laplace, now more facility in his researches. In 1819 he was placed
than seventy years of age, opposed the new opinion on the Commission for the Management of the
to the last. His reason for doing so was eminently Lighthouses of France (of which he afterwards be-
characteristic of the great geometer-—“ it was one to came Secretary), and he entered with ardour on the
which analysis could not be applied without much application of his favourite science of optics to the
difficulty;” to which Fresnel replied, “ that it was duties of his profession and the benefit of man-
still harder to believe that the laws of nature were kind.
arrested by such obstacles.” Poisson, as might have The use of lenses in place of reflectors for prevent- (49”-)
been expected, was equally opposed to the undula- ing the indefinite dispersion of the light employed,
tory doctrine, for he was still less of a physicist than and the effectual concentration of it in the direction
Laplace. His standing argument against it was its where it will be most useful, was not altogether new.
inability to explain dispersion. M. Biot, also a keen The construction of immense lenses of glass of no
supporter of Laplace, was still more strongly com- great thickness, formed by grinding out a series ol
promised to the theory of emission. The inertia of concentric refracting surfaces having a common focus,
such authorities at the Institute retarded of course had also been proposed by Buffon, and the idea of
the growth of Fresnel’s reputation at home, notwith- constructing these rings or echelons separately and
standing the great weight of his friend Arago’s opi- then uniting them had been suggested by Condorcet
nion. It was in fact in England that the merits of in his eloge of Buffon, as well as at a later period
2 Peacock’s Er/e o/ Young, p. 401.
Chap. V., § 4.] OPTICS-
by Sir D. Brewster. These proposals were all alike
unknown to Fresnel, who had the grand merit, in a
case of this kind, first, of carrying his happy idea
into effectual execution, and secondly, of giving it a
wonderful extension by the invention of a multitude
of other forms of refracting and totally reflecting
apparatus, till then unimagined as well as unexe¬
cuted.1 In 1823 the lighthouse of Corduan, at the
mouth of the Garonne, was furnished with the new
lenticular system, which was very skilfully executed
by Soleil of Paris. The illumination was provided
by means of a beautiful and powerful lamp with se¬
veral concentric wicks, the joint invention of Fresnel
and Arago, which gave twenty-five times the light
of the best Argand then in use. The system was
found to work so well that it was speedily extended
in France, then to Holland, and in the third place to
Scotland, principally through the energy of the late
Bobert Stevenson and the present Mr Alan Steven¬
son, his son, to the latter of whom we owe the best
and most compendious treatise on the subject of
lighthouses,2 as well as the noblest exemplification
of it in the Skerryvore Lighthouse, erected by him
in 1843. The same small work contains the details
of Fresnel’s admirably ingenious applications of the
principle of refraction to the distribution of light
under almost every circumstance, which were not,
however, published by their inventor.
(498.) In 1824, consequent upon his exertions as exa-
miner at the Polytechnic School, Fresnel had the
first seizure of the malady which brought him to the
grave at the premature age of 39, on the 14th July
1827. Eight days previously to his death he had
received at the hands of Arago the Rumford medal
before referred to, which his distinguished friend
-ARAGO. 907
Malus had obtained under like melancholy circum¬
stances 16 years before.
From what has been stated it will appear that (499.)
Fresnel eminently possessed the qualities requisite ^ Fresnel
for original investigation. So finely balanced a com¬
bination of mathematical skill and attainment with
profound inductive sagacity has rarely been wit¬
nessed. Had Young not happened to precede him
there can be no question but that he would have made
the undulatory theory entirely his own. Fresnel was
superior to Young in the talent for devising and
executing critical experiments, in which indeed he
showed a degree of skill equally rare and admirable.
It is hoped that his surviving brother, M. Leonor Fres¬
nel, who is well qualified for the task, will collect his
scattered papers and edit them, with a suitable bio¬
graphy. The eloge of Fresnel, written by the man most
competent to render him justice—Arago—remained
more than twenty years among the unedited papers
of that philosopher, and has only appeared since his
death in 1853. The cause of this suppression was
one of those partly political and partly personal dis¬
putes which seem almost inseparable from the pro¬
ceedings of the Institute. The eloge was announced
to be read just two days before the Revolution of
1830 burst forth ; Arago could not persuade him¬
self at such a moment to discuss the merits of the
Theory of Double Refraction without committing
himself also on the politics of the day. Disputes arose,
friendships cooled, and the unlucky work was re¬
turned to the author’s desk. Hence no biography of
Fresnel appears in the publications of the Institute,
but his reputation will be treasured in France and
elsewhere, when the more conspicuous laurels of many
of his compeers are withered and half-forgotten.
4. Arago.3—Short Account of his Scientific Career—He discovers the Colours of Polarized
Light—Laws and Theory of Depolarization; M. Biot; Young; Fresnel.—Non-interference
of oppositely Polarized Rays—Rotatory Action of Quartz.—M. Foucault’s Experiment on
the Velocity of Light.
(500.)
Arago:—
(501.)
his earh'
life;
Dominique Francois Jean Arago, one of the most
generally known of the philosophers of the half cen¬
tury just elapsed, though the author of a large num¬
ber of miscellaneous writings which since his death
have been edited in a collected form, has not left an
amount of positive contribution to any one of the
sciences at all in proportion to the reputation for
ability which he very justly enjoyed.
He was born at Estagel near Perpignan, on the
26th February 1786, and the ardent temperament of
a native of the south was one of his chief character¬
istics. From a fragment of his early history which
he left behind him, it appears that he educated him¬
self almost without assistance, and that when he
was admitted to the Polytechnic School in 1803 (con¬
sequently at the age of 17), he was intimately
acquainted with the chief writings of Lagrange,
had studied the Mecanique Celeste, and had conse¬
quently in his possession far more mathematical
knowledge than would have been required of him on
leaving that celebrated institution. From the Poly¬
technic School he passed into the position of Secre-
1 One of Fresnel’s lenses was used in 1821 for the geodetic operations connecting France and England, and the light was ob¬
served at a distance of fifteen marine leagues one hour after sunset.
2 Rudimentary Treatise on Lighthouses, by Alan Stevenson. Weale, 1850. See also the Account of the Skerryvore Lighthouse,
with numerous plates, in 4to, 1848.
3 I may perhaps be thought to give Arago too prominent a place in the history of Optics. If so, it has arisen in part from
908
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
tary to the Paris Observatory. He pursued with M.
Biot experiments on the refraction of the gases, and
in 1806 the two young philosophers were despatched
to the south of France and to Spain to continue the
triangulation interrupted by the death of Mechain.1
Geodetical The next three years were spent by Arago in a series
observa- 0f voluntary and involuntary journeys, perils by land
tl0ns' and sea, from robbers, and from the Spanish govern¬
ment and populace, such as have been rarely equalled,
—perhaps never in the pursuit of science. The decla¬
ration of war against France rendered his stay either
in Valentia or in the Balearic Isles impossible, and
he was conveyed in disguise from Majorca to Algiers,
whence he twice essayed to reach Marseilles, but
was once driven back to Africa by a storm, once
made prisoner by a Spanish corsair. After great
suffering, he at length reached France in July 1809,
carrying with him the precious record of his geodeti¬
cal operations. From this time his promotion was
assured, and his life became tranquil and inactive, al¬
though the deep attachment which he formed with
Baron Humboldt immediately on his return to France
would probably have induced him to accompany that
enterprising traveller to Central Asia, had that jour¬
ney ever been accomplished. At the early age of 23
Arago attained the position of Member of the Insti¬
tute, and was again attached to the Paris Observa¬
tory, of which at a later period he became director.
He took a very active share in the proceedings of the
Academy of Sciences, and became one of its secre¬
taries in 1830.
(502.) From the period of his election to the Institute,
Arago’s Arago’s career was destitute of stirring incidents, but
subsequent w from first to last, devoted chiefly to science. It is
certain, however, that he was deficient in that power
of continuous application, to which alone great dis¬
coveries are commonly due. Full of ingenious, origi¬
nal, and even profound conceptions, he shunned the
labour of realizing them. His appointment to the
charge of the Observatory of Paris was perhaps unfor¬
tunate. Well versed in the theory of astronomy, the
minute drudgery of observation and the control of
numerous assistants, was altogether uncongenial to
him. It was a duty imperfectly fulfilled, to say the
least, for 40 years: and it is needless to add how much
the consciousness of habitual neglect of a duty deadens
the faculty of useful application to anything else.
(503.) science of astronomy then owes little to
Arago, beyond the part which he took in geodetical
observation, what are we to consider his chief claims His optical
to a place in this history1? I have no hesitation inlabours°f
saying that they are to be found in connection with™8^™^
the discoveries and labours of his attached friends,1
Malus and Fresnel, and therefore we group them to¬
gether in this chapter. Arago not only himself made
some important optical discoveries in 1811 and the
following years, but he was instrumental, as we have
seen, in a very important degree, in calling forth the
genius of Fresnel, and in obtaining a public recogni¬
tion of the labours of Young ; a service not the less
wTorthy of note because of its eminently disinterested
character. The undulatory theory of light, one of
the greatest triumphs, if not the greatest, of our age,
stands where it does in no slight degree through
the instrumentality of Arago.
One of his most considerable discoveries was that (504.)
of the colours which crystallized bodies develop in Colours of
white lierht polarized before incidence on the crystal, crystallized
and afterwards transmitted through a rhomb of calc- polarized
spar. These colours, by their order, the singular man- light,
ner of their occurrence and disappearance, and in cer¬
tain cases by their extraordinary and beautiful forms,
offered a problem at once the most attractive, the
most definitely marked, and the most seemingly in¬
explicable which had been met with in optics for much
more than a century. They exemplified a new mode
of analyzing light, evidently connected with the mole¬
cular forces concerned in crystallization; and for their
display it was necessary that light should be in that
peculiar and yet mysterious state called polarized.
The substances he employed were principally sele- (505.)
nite, rock-crystal, and mica. When plates of thePhenoinena
first and last of these minerals, formed by their natu- ^a^°lar'
ral cleavage, are placed in a beam of polarized light,
and the light transmitted by them is then analyzed,
by being passed through a doubly-refracting prism or
thrown on a screen after reflection at the critical angle
from glass, splendid colours are the resxdt. These
colours vary with the thickness of the plate, with its in¬
clination to the incident light, and, what is most remark¬
able, they vary in intensity bymerely turning the plate
of selenite round in its own plane. When only this last
motion is made, there are two positions of the plate
where no colour results, the light passing through un¬
changed; and these positions are at right angles to one
another. At all intermediate angles colours appear, the
light is said to be depolarized, and this depolarization
is most complete when the plate is moved 45° from
the difficulties inseparable from the biographical system which I have adopted. My intention was to have thrown together the
labours of Malus, Fresnel, and Arago into one section. But having written the different portions separately, there seemed so
much precision and facility of explanation to be derived from treating of them consecutively, that I sacrificed, in some degree,
the biographical principle to that of systematic classification; placing under the name of Malus what referred to the empirical
laws of double refraction; under that of Fresnel the doctrine of transverse vibration (though mainly due to Young); and under
Arago the discoveries of \oung, Fresnel, Biot, and others, relative to the great subject of chromatic polarization, to which he
gave the first impulse. The establishment of the undulatory theory, principally due to Young, Fresnel, and Arago, 1 have con¬
sidered as deserving of a more detailed and systematic treatment than almost any other of the numerous discoveries of which I
have to speak in this Dissertation. I may add, that the biography of Arago not appearing in its alphabetical place in the En-
cyclopczdia, M. Arago being still alive at the date of the publication of that part of the work, it has been incumbent upon me to
enter into more details than I should otherwise have done. l See Chapter III., Art. (166) of this Dissertation.
OPTICS.—ARAGO.
909
Chap. V., § 4.]
(506.)
Observa¬
tion of
Mai us,
Arago, Sir
D. Brew¬
ster, and
M. Biot,
attributed
to inter¬
ference by
Young.
Case of
rays oppo¬
sitely po¬
larized—
Arago and
Fresnel.
(507.)
Depolari¬
zation ex¬
plained on
the undu-
latory
theory.
the positions in which the light passed through un¬
changed.
The theory of this simple yet admirable experi¬
ment is one of the happiest examples of Fresnel’s
mechanical explanation of double refraction. But
it was not attained by a single step, nor effected
by a single hand. Malus had observed the fact of
depolarization, and the existence of perpendicular
neutral axes in the crystalline plate. Arago added
to this the knowledge of the phenomena of colour,
which Sir David Brewster also observed indepen¬
dently somewhat later. He also invented a par¬
ticular theory to explain them by what he termed
moveable 'polarization. But it wras not a success¬
ful effort. M. Biot assiduously studied the empi¬
rical laws of these periodic colours, and traced
their dependence on the thickness of the interposed
plate, according to a law similar to that of Newton’s
rings. Young made an important step farther. He
attributed the colour to the interference of the ordi¬
nary and extraordinary rays into which the incident
light was divided on entering the crystalline plate ;
and he showed by accurate calculation that the retar¬
dation of the slower-moving of the two rays during
their passage through the plate, did in fact produce
the difference of phase necessary for developing the
tints observed by their reunion on leaving the plate,
according to the usual laws of interference; and he
showed that this theory coincided with M. Biot’s
rules.1 But even this was not enough to explain the
facts. It wras not clear why the colours due to doubly-
refracting plates should not be seen without reaching
the eye through an analyzer, or calc-spar prism. To
Arago and Fi'esnel jointly we owe the important
reply to this difficulty, which in fact forced upon the
latter the idea of transversal vibrations. Their joint
experiments (mentioned in the last section, art. 488),
had shown that oppositely polarized rays cannot in¬
terfere unless they have, first, a common origin and a
common plane of polarization; and, secondly, unless
they be reduced to a common plane of polaiization
(that is, analyzed) before falling on the eye or the
screen : so that the theory of the colours of crystal¬
lized plates is, briefly, as follows :—
Polarized light is represented by transverse vibra¬
tions of ether, the particles moving all in one plane.
The crystallized plate has, we will suppose (in order
to take the simplest case) one axis of double refrac¬
tion, and the direction of that axis is in the plane of
the lamina. When the vibrations of the light falling
on the crystallized plate are either wholly parallel or
wholly perpendicular to this axis, the light is trans-
nfitted without alteration, either as an extraordinary
or as an ordinary ray, and it is then reflected or not
by the analyzer, as would have been the case had it
not been transmitted at all through the crystal of
selenite. But if the axis of the crystal be inclined,
suppose 45°, to the plane of vibration of the incident
polarized ray, the vibration is mechanically resolved
into two, which are oppositely polai’ized. After tra¬
versing the thickness of the crystallized plate with
the different velocities due to the motion of the ordi¬
nary and extraordinary rays, they are reunited at
emergence, but in altered relative phases, so that by
their union they form a beam no longer polarized
(unless by an exception) in the same plane as at first,
nor indeed plane-polarized at all, but most likely per¬
forming elliptical or circular vibrations, which, again,
falling on the analyzer, are reflected or transmitted,
or partly both, in a manner quite different from what
wnuld have happened to the light unchanged by crys¬
talline transmission.
White light becomes coloured because the state of (508-)
. . . & „ , , , , Cause of
polarization ot the emergent ray depends on the diner- the colour.
ence of length of path for the two rays which under¬
went crystalline separation within the plate, and also
on the length of a wave of light (for this determines the
phase of polarization at emergence). But the wave
of light varies in length for each colour, consequently
every colour has its maximum under different circum¬
stances, and if the incident light be white, the light
falling after reflection on a screen will present mixed
tints similar to those of Newton’s rings.
This extraordinary property of a crystallized plate
(which, in common light, appears equally transparent
and homogeneous in every direction), of modifying
light, or dyeing it with the most gorgeous colours,
when the plate is merely turned in its own plane, is
one of the nicest tests of the polarization of the light,
and has been used to detect the analogous polariza¬
tion of radiant heat, and the concomitant phenome¬
non of double refraction, which, except in the case
of the heat accompanying the solar rays, has not
yet been independently recognized.2
Arago applied his discovery to the construc¬
tion of a polariscope, for estimating the feeblest
amount of polarization ; and he used this instru¬
ment for some very interesting experiments on the
polarization of the light of the sky (which is sun¬
light polarized by reflection from the atmosphere),
and on that of different incandescent and reflecting
surfaces. He also found that the moon and the
tails of comets send light to the eye which is slightly
polarized, thus betraying its borrowed origin. But
that of the sun, being absolutely neutral, is only
comparable (according to Arago) to the light arising
from incandescent vapours, thus distinguishing the
sun from a solid or liquid globe.
We cannot do more than allude to Arago’s other
optical papers and experiments. He was, probably,
the only Frenchman of his time who was well ac¬
quainted with Young’s discoveries. The explana-
(509.)
Similar
pheno¬
menon in
radiant
heat.
(510.)
Arago’s po¬
lariscope.
(511.)
Experi¬
ments on
Newton’s
rings and
1 Quarterly Review, vol. xi. ; Miscell. Works, vol. i., p. 266.
See Researches on Heat by the present writer. Edinburgh Transactions, vols. xiii. and xiv.
910
MATHEMATICAL AND PHYSICAL SCIENCE.
[Biss. VI.
on the ro¬
tatory ac¬
tion of
quartz.
(512.)
tion by the doctrine of interference of the colours
of Newton’s rings received an important confir¬
mation from an experiment of Arago’s, which proved
them to arise from the mixture of the pencils
of light reflected at the two neighbouring sur¬
faces. He pressed a lens of glass against a plate of
metal, in which case the central spot is white or
black when light polarized perpendicularly to the
plane of incidence is reflected at an angle greater or
less than the polarizing angle for glass ; and the rings
vanish altogether at the polarizing angle ;—results
which have been found conformable to the undulatory
theory.1 He also discovered the peculiarity of the
rays transmitted along the axis of a crystal of quartz.
These depolarize light, or produce colours similar to
those of crystallized plates, varying according to a
well-marked law with the thickness of the plate.
The most singular fact is, that by turning round the
analyzing plate, no position of neutrality is found,
but a series of colours similar to those of Newton’s
scale succeed one another. Arago showed that this
effect is due to a rotatory motion of the plane of polar¬
ization within the crystal. The rotation is greater
for the violet than the red ray; this was shown by
M. Biot, who also discovered that in some specimens
the rotation takes place from right to left, in others
from left to right—a peculiarity connected with cer¬
tain crystallographic modifications, as was first
shown by Sir John Herschel.
MM. Seebeck and Biot discovered an analocrous
Rotation of property in oil of turpentine, and in various saccharine
tho plane fluids an observation which, in many cases, allows the
ofpolariza- n • . •to
tion in substitution ot an instantaneous optical,for an operose
fluids. chemical test. Fresnel has shown that the phenomena
of quartz may be represented on the supposition that
the rays traversing the axis consist of twTo rays circu¬
larly polarized in opposite directions, and travelling
with different velocities; and Mr Airy succeeded in
calculating, by the aid of this fundamental hypothesis,2
a number of most beautiful and complicated pheno¬
mena, such, for example, as those which occur
when plates of right and left handed quartz are
superposed. Maccullagh has shown how the ge¬
neration of elliptical or circular vibrations may be
deduced from the general equations of motion, but he
has not invented a mechanical theory to explain
them. This is a point of the very highest interest,
inasmuch as Dr Faraday has succeeded, for the first
time, in inducing artificially in a substance the power
of rotating the plane of polarization by the presen¬
tation of it to the poles of a most powerful magnet.3
(513.) Ai'ago’s experiments on the non-interference of
Retarda- rays of light oppositely polarized, being undertaken
nonoflight in conjunction with Fresnel, have been already re¬
ferred to, arts. 488 and 506 ; but to Arago alone is in dense
due the ingenious idea of interposing a thin slip ofmedia
mica or blown glass in the path of one of the inter- by
fering pencils, and observing the displacement of the " raS°‘
interference-bands, which is always towards the side
of the interposed slip, showing that the movement
of the wave has been slower within the denser me¬
dium.
Arago continued to attach great importance to the /5U
obtaining of a still more direct proof of this fact, which Experi-
he considered as a crucial one between the rival hypo- ment to the
theses of Newton and Huygens. In his last years he
had the satisfaction of witnessing the accomplishment cault. °U'
of it, with the result he anticipated, and by a method
which he had himself indicated. In 1838, he had al¬
ready indicated the application of Mr Wheatstone’s
beautiful invention of the revolving mirror,4 as a means
of measuring intervals of time incredibly short, in order
to compare the velocity of light in air, and in a corre¬
sponding length ofwater. He even caused an apparatus
to be partly prepared, but we have seen that Arago’s
forte was rather in suggesting than in completing re¬
searches. After his inci’easing failure of sight ren¬
dered it physically impossible that he should ever
realize his own idea, it was skilfully adopted by M.
Foucault (the author of the admirable experiment
with the pendulum, demonstrating the earth’s mo¬
tion5), who, by an ingenious combination of fixed and
revolving mirrors, succeeded in 1850 in demonstrating
the retardation of light in a tube of water only 6^
feet long, and with a velocity of rotation of the move-
able mirror not exceeding 200 turns in a second (a ra¬
pidity four times less than had already been obtained
by Mr Wheatstone). The rotation was produced
by means of the Sirene of M. Cagniard de la Tour,
acting by steam. The velocity was thus raised to
1000 revolutions. It was afterwards, however, carried
by MM. Fizeau and Breguet to 2000 revolutions. It
will be understood, from the account of the method,
as applied to the measurement of the velocity of elec¬
tricity, in another chapter, that the retardation is
shown by the displacement of the image of a minute
object seen through the water, relatively to the image
of the same object seen in air. If light moves faster
in water (as Newrton imagined), the displacement of
the water-image will be (let us say) to the right; but
if slower (as Huygens and Young believed), it will
be to the left. The calculated displacement, with
800 revolutions in a second, was '004 inch on the
first supposition, and ‘003 in the opposite direction
in the second, quantities easily visible with a high
magnifying power. The result, as has been stated,
confirmed Arago’s original experiment of 1815 on
the displacement of the interference fringes.
. 'r.^' Herf0h0f fyrme<l Newton s rings between glass and metal. Arago’s experiment was reproduced (unknowingly)
y2 w-ilrIm I f? ■’ u St eXP.lained ifc fully ^ the undulatory sense. Camb Trans., vol. iii.
tion increased aC^ltl0n, t°at ra^S inciined to th® axis are elliptically polarized, and that with a greater ellipticity as the inclina-
3 See the chapter on Electricity, § 5.
4 See Electricity, § 6.
5 See the chapter on Astronomy, Art. (258).
Chap. V., § 5.]
OPTICS.—SIR DAVID BREWSTER.
911
(515.)
Arago’s
electro¬
magnetic
observa¬
tions.
(516.)
Essays
on meteor¬
ology.
(517.)
To complete our biographical notice, we will here
just allude to M. Arago’s principal researches un¬
connected with optics. One was on the magneti¬
zation of iron filings, and the formation of a tempo¬
rary magnet, by means of a helical conductor of elec¬
tricity j1 the other was the important observation of
the seeming magnetism of copper, and other non-mag-
netic metals, when put in rapid rotation near a per¬
manent magnet. Neither of these happy experiments
was carried out by their author. The former was left
in the hands of Ampere, Sturgeon, and Heni’y; the
latter was only rightly understood and valued when it
was engrafted by Mr Faraday on his splendid series
of researches on Magneto-Electric Induction.2
Arago is fairly entitled to be regarded as having
'proved the long-suspected connection between the
aurora borealis and the freely suspended magnet; and
this in the face of urgent contestation. His contri¬
butions to Meteorology (founded rather upon the ob¬
servations of others than upon his own) were of con¬
siderable importance, and several of his popular pa¬
pers, appended to the smaller Almanac {Annuaire)
of the Board of Longitude, contain a great deal of
well-digested and curious information.
As Secretary of the Academy of Sciences in the
Mathematical Department (in which office he sue- Arago as
ceeded Fourier, in 1830), the duty devolved on him secretaiT °*
of writing the biographies of eminent deceased mem-^g^y
hers of the Academy. He bestowed extraordinary Sciences,
pains on these compositions, and strove to render
them popular without sacrificing their scientific cha¬
racter. In this difficult attempt he was not always
successful. Abrupt transitions, piquant anecdotes,
paradoxical arguments, and political allusions,appear,
at least to the English reader, to be unacademical
adjuncts to the history of contemporary discovery.
The special pleader is too often visible, and even the
occasional sacrifices of the strong spirit of nation¬
ality by which he was commonly actuated, to some
chivalrous adjustment of the rights of discovery,
do not always carry conviction to the mind of the
reader. The Eloge of Watt, probably the most po¬
pular, appears to us far from being the best of these
biographies. Those of Sir W. Herschel and of Dr
Young are ably executed, and display much research
and candour.
After having been for three years almost with- (518.)
drawn from science by lingering disease, and nearly His death,
complete blindness, Arago expired at the Observatory
of Paris, on the 2d October 1853, aged 67.3 *
5. Sir David Brewster—Progress of Experimental Optics—Laws of Polarization—Double
Refraction produced by Heat and Compression—Discovery of Biaxal Crystals—Laws of Me¬
tallic Reflection—Absorption of Light; and Lines of the Solar Spectrum ; Fraunhofer.—
Seebeck; M. Biot.
(519.) We have pleasure in ranking amongst the fore-
Sir David most promoters of the science of optics in its sur-
Brewster. prising revival in the earlier part of this century,
a philosopher who still lives amongst us and pur¬
sues with ai’dour the investigations of his youth.
(520.) Sir David Brewster was born at Jedburgh, in
His early Scotland, on the 11th December 1784. He was
studies. educated for the Scottish Church, and having en¬
tered the University of Edinburgh at a very early
age, pursued his studies under Robison, Playfair,
and Stewart, and formed the friendship of those
eminent men. Amongst fellow-students of no
common distinction who at that time frequented the
college lectures, and of whom not a few were destined
to signalize themselves in literature, science, and the
career of politics, he formed the particular acquaint¬
ance of Mr, now Lord Brougham, and through him
was led to study the inflection of light, and to repeat
Newton’s experiments. This was in 1799 ; nor did
he afterwards lose sight of a science which he was
so signally to improve. The distraction of other
occupations, the calls of his profession, and his
indifferent health prevented, however, any very
constant application to optics: and the part of
the subject he then principally studied was rather
connected with the use and theory of instruments than
with physical optics in the sense in which we have
explained it. This is evident from his first separate
publication in 1813, “ on new Philosophical Instru¬
ments,” which, though containing many ingenious
and valuable suggestions, fell short of the importance
of his subsequent publications.
Sir David Brpwster’s genius was first called forth (521.)
by the announcement of Malus’s great discovery Directs his
in 1808 of the polarization of light by reflection, t0
But for the unfortunate political relations of France optics,
and England at the time, which prevented, to a
degree which now appears almost incredible, the
transmission of even the most interesting scientific
facts from one country to the other, our country¬
men would have borne a larger share in the dis¬
coveries which immediately followed; and it would
have been an easier task to apportion with his¬
torical accuracy what was due to each. As the
French philosophers remained long in ignorance of
the discoveries of Davy, and were anticipated in
every important step in voltaic science, so Malus and
Arago pursued and published researches and bril-
1 See Electricity, § 4. 2 Electricity, § 5.
3 The article Polarization of Light in this Encydopcedia, the production of Arago, contains an excellent review of many
of the topics of this Section.
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(522.)
Treatise on
new philo¬
sophical
instru¬
ments.
(523.)
His re¬
searches on
optical sub¬
jects.
(524.)
Enumera-
of the most
important.
(525.)
Law of po¬
larization
by reflec¬
tion.
912
liant discoveries which, literally for years, remained
unknown in England to those most interested and
solicitous to learn them. Thus Sir D. Brewster
learned first in February 1814 that Malus had m
March 1811 published the discovery of the polar¬
ization of light by refraction, which he also had made ;
whilst Arago’s experiments on coloured polarization
were likewise unknown to him through the same
want of international communication.
The work on Philosophical Instruments, men¬
tioned above, contains, besides what its name more
particularly imports, numerous observations on re¬
fractive and dispersive powers, including the disco¬
very of substances more refractive than diamond,
and less so than water. It also describes the pro¬
perty of some agates to transmit light polarized in
only one plane. The imperfect polarization of light
by metals and by a serene sky had been anticipated
by Malus and Arago.
From this time (1813) Sir David Brewster became
a regular contributor to the London Philosophical
Transactions, which, as well as those of Edinburgh,
contain a series of elaborate experimental investi¬
gations due to him, which have hardly been sur¬
passed. It is difficult to overrate the importance of
these researches, whether for the intrinsic interest
of the phenomena they reveal, or for the significance
of the empirical laws by which their author, with
a rare sagacity, succeeded in classifying facts, and
afforded a sure basis for farther generalization. The
number and variety of these researches is so ex¬
ceedingly great, and in many cases so impossible
to explain without entering into minute detail, that
I shall, in accordance with the plan of this essay,
merely indicate some of the most generally impor¬
tant by arranging them in groups. Such are—
I. The laws of polarization by reflection and re¬
fraction, and other quantitative laws of phenomena.
II. The discovery of the polarizing structure in¬
duced by heat and pressure.
III. The discovery of crystals with two axes of
double refraction, and many of the laws of their phe¬
nomena, including the connection of optical structure
and crystalline forms.
IV. The laws of metallic reflection.
V. Experiments on the absorption of light.
L Malus had failed to discover a connection be¬
tween the angle at which light is completely po¬
larized by reflection, and the other known optical
properties of bodies. In 1814, Sir D. Brewster
discovered the beautiful and simple law, “ that the
index of refraction is equal to the tangent of the
angle of polarization.” He had suspected it much
sooner, but he had been baffled by the irregular re¬
sults obtained by reflection from glass, whose sur¬
face he found to undergo an almost imperceptible
chemical change. He further observed that it is
only in bodies of low refractive power that the po¬
larization is sensibly complete, a result of great im¬
portance, which has been too much overlooked until
the recent and valuable paper of Jamin on the same
subject. He deduced as a corollary, that at the
maximum polarizing angle the incident and refracted
rays are at right angles to one another, and also
Malus’s experimental result that the rays reflected
from the first and second surfaces of plates are
simultaneously polarized. He further discovered the
fact that light may be completely polarized (as to
sense) by a sufficient number of reflections at any
angle, and drew the conclusion that the whole light
undergoes some change at eacli reflection, in opposi¬
tion to the view of Malus, who maintained that,
except at the polarizing angle, a portion of the light
is polarized, and the rest is unchanged.
Sir David Brewster independently observed the po- (526.)
larization of light transmitted obliquely through glass,
and he calculated the number of plates necessary to P^nza'
polarize it with sensible completeness. All these
researches he resumed some years after [Phil. Trans.
1830), endeavouring to give a photometric estimate
of the effects of reflection and refraction under all
circumstances. The results as regards partially po¬
larized light may still be considered as subject to
doubt. His skill in obtaining a mathematical repre¬
sentation of the phenomena was again displayed in a
number of laws connecting the experimental results.1
II. Malus had observed that a vast number of (527.)
substances depolarized light more or less completely;
and Arago found feeble traces of chromatic polar-
ization in some specimens of glass. But the more glass;
definite characters of the beautiful phenomena of
glass not perfectly annealed (which proved to be of
unexpected importance) were noticed, independently,
by Sir D. Brewster and Dr Seebeck of Nurnberg.
The latter had priority in publication,2 but the former
correctly referred them to their immediate cause—
the constraint produced by rapid cooling. Sir D.
Brewster noticed that the unannealed glass which
forms what are called Prince Rupert’s Drops, had a
remarkable power of depolarization; and he also
observed subsequently that the plates of glass be¬
tween which he was in the habit of squeezing heated
wax and resins, for the purpose of optical examina¬
tion, transiently communicated tints to polarized
light. These observations, duly developed, proved
on the one hand that glass (and generally refracting
1 Thus he found that the effect of refraction on the plane of polarization of the incident light may he expressed hy this
simple formula—cotan a — cotan a cos (i — i"'), where a and a/are the azimuths of the planes of polarization of the incident
and refracted rays measured from the plane of reflection, and i and i’ the angles of incidence and refraction. This result, ad¬
mirably verified by experiment, is also conformable to Fresnel’s theory.
2 In Schweigger's Journal for 1813, vol. vii. I have not been able to find in this paper (which contains the first account of
the beautiful symmetric coloured figures displayed in cubes and cylinders of glass) the smallest trace of the true cause of the
phenomenon, viz., the sudden or partial cooling of the glass.
Chap. V., § 5.]
OPTICS.—SIR DAVID BREWSTER.
913
solids not usually possessed of any polarizing action)
acquired such properties by being suddenly and un¬
equally cooled; and on the other, that such sub¬
stances undergoing partial changes of temperature,
possess the same property. These phenomena are
exceedingly beautiful, and easily displayed. It is
sufficient to place a rectangular piece of glass, some¬
what thick, with one of its longer edges in contact
with a hot iron, and placing it between a polarizing
and analyzing plate, to incline the heated edge 45°
to the plane of polarization. Bands of light and
shade are seen to traverse the glass parallel to the
same edge, and simultaneously appear also on the
side farthest from the heated metal. They pass gra¬
dually into rich coloured tints diffused with geometric
regularity. In the case of cubes or cylinders of glass,
suddenly, and therefore unequally cooled, the pheno¬
mena are permanent, and the colours splendid, being
arranged in patterns which may be made to resemble
those of natural crystals.
(528.) Sir David Brewster at first ascribed these effects
and in t0 direct effect of the heat in the glass upon
jected to " and compared its simultaneous influence over
pressure, a whole plate to a polar influence. Another curious
discovery, also due to him, leads to the simpler con¬
clusion, that in every case the development of a
polarizing structure is due to the varying tension
(transient or permanent) into which the particles of
the glass are thrown by local expansion or by irre¬
gular cooling. This discovery was, that similar
effects may be produced in jellies and soft transparent
substances by the effect of pressure, and that even
glass itself, when strained in any way by mechanical
force, shows depolarizing bands ; and crystals may
have their peculiar optical phenomena altered by
pressure. Fresnel, not satisfied with inferring that
the chromatic display is due to a doubly-refracting
structure communicated to the glass, contrived, by
an ingenious arrangement of prisms, actually to
exhibit the separation of the images under the action
of powerful pressure.
(529.) III. Possibly the most remarkable of Sir David
Discovery Brewster’s discoveries,—at all events, that which
crystals! probably cost him most labour to develope,—was that
there are crystals possessing two axes of double re¬
fraction, and showing many remarkable phenomena,
which indicate a connection between optical structure
and crystalline form. No one before him suspected
the existence of a doubly-refracting structure differ¬
ing from that so ably investigated by Huygens and
Malus in Iceland spar. In 1813 Sir David Brew¬
ster had discovered coloured rings in topaz when
viewed by polarized light. Though intimately con¬
nected with M. Arago’s observation of colours in
crystallized plates, these interesting phenomena had
a still more extraordinary and geometrical character.
When a plate of topaz, split by natural cleavage, was
presented between the polarizing and analyzing plate
(or rhomb of calc-spar), and at the same time
inclined in a certain manner, the colours were no
longer in broad sheets, but, if viewed closely, they
arranged themselves in oval rings of great beauty,
presenting orders of mixed colour analogous to those
described by Newton when formed between convex
glasses, and they were traversed by dark or white
brushes as the analyzing plate was held in the
dark or bright position. A second such system was
observed inclined at an (apparent) angle of 65° in the
same plate.
Dr Wollaston afterwards (1814) discovered a phe- (530.)
nomenon equally beautiful in calcareous spar, ofPhenornena
which Sir D. Brewster had already perceived traces tfon^shown
in some other crystals. Concentric with the posi- by uniaxal
tion of the axis of double refraction (or optic axis), crystals,
in a crystal of that mineral cut with two parallel
faces perpendicular thereto, a series of perfectly sym¬
metric and exquisitely coloured rings are seen in po¬
larized light, having a white or black cross travers¬
ing them, according to the position of the analyzing
plate. This magnificent phenomenon, which (except¬
ing, of course, the rings of biaxal crystals mentioned
above) has perhaps no parallel in optical science, is
seen in the most perfect manner possible in an appa¬
ratus constructed solely of Iceland spar, cemented by
Canada balsam. A Nicol’s single-image prism1 is
used to polarize, another to analyze the light, and
between them is a plate of calcareous spar properly
cut. It is a truly astonishing paradox to see the
union of three perfectly transparent and colourless
crystals display by their union such an exquisite
combination of form and colour. The pole or centre of
the rings in calc-spar coinciding with the axis of double
refraction, of necessity suggested the idea that topaz,
which shows two systems of rings arranged round two
poles, must possess two axes of double refraction ;
in other words, that there must exist within the
crystal two directions (not mere lines), parallel to
which a transmitted ray emerges without subdivision
into two pencils.
This probable conjecture was verified by careful (531.)
obseiwation, not only in topaz, but also in a vast Double sys-
variety of other crystals which were found by Sir t®ar“s
David Brewster much more commonly to possess two^’ m re’
than one system of rings. Amongst the earliest ex¬
amples which he observed were nitre, mica, acetate of
lead, and Rochelle salt. Of these the first is exceed¬
ingly remarkable for the small inclination of the axes
(about 5°) which permits both systems of rings to be
readily observed at once. It was not, however, for
some years (1817) that he reduced these most
1 The invention of a most ingenious person, the late Mr William Nicol of Edinburgh. One of the doubly-refracted rays is
thrown completely out of the field by undergoing total reflection at the surface of a film of Canada balsam in contact with the
spar, whilst the other less refrangible ray proceeds quite isolated, and with scarcely any loss of brilliancy. It is of almost
universal application in this branch of Optics.
yol. r. 5 z
914
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
carious phenomena to anything like a law. It was
evident almost from the first, that the axes in ques¬
tion (which he termed axes of no polarization) are
only the vesuiitauts of remoter fundamental actions of
the crystalline constitution. I or example, these
axes vary in position according to the colour of the
light used to display them ; their position within the
crystal varies (as was shown by Mitscherlich) with
the temperature of the body, nor is it obviously
related to any of the geometrical lines of crystalliza-
Law of the tion. Sir David Brewster succeeded in finding the
tints. jaw 0f the tints expressed upon the surface of a
sphere of which the directions of the two axes form
diameters. M. Biot expressed the law more ele¬
gantly by saying, that the tint developed by a biaxal
crystal in any ray, is proportional to the product of
the sines of the angles which the ray in question
makes with the two optic axes. The tints are con¬
sequently arranged round the two poles of the axes,
in a series of curves resembling the figure 8, having
each this property, that the product of the sines of
the angular distances of each point of one curve from
the two poles is equal to a constant quantity. Such
curves are called lemniscates, and are beautifully
seen in nitre, especially when viewed by homoge¬
neous light.
(532.) A series of researches of the most elaborate
Kelation of description led Sir David Brewster to this addi-
optical cha- ^ona) an(f admirable discovery, viz., that the optical
crystalline characters of single refraction, double refraction
forms. with one axis, and double refraction with two axes,
have reference invariably to the primitive crystalline
form of the mineral, and that the complexity of the
optical character is as invariably related in degree to
the complexity of the crystalline figure. Cubical and
regularly octahedral crystals (as rock salt and fluor
spar) being possessed of perfect symmetry in three prin¬
cipal directions, possess also simple refraction. Crys¬
tals with one predominant line or axis of symmetry
—as rhombohedrons, octahedrons with square bases,
right prisms with square or hexagonal bases—have a
single axis of double refraction. Such, for instance, are
Iceland spar, zircon, ice, beryl. Finally, all crystals
unsymmetrical in the three principal directions, in¬
cluding prisms and octahedrons whose bases are
not square, and those which are oblique, have two
axes of double refraction. The rarity and minute¬
ness of many crystals, the difficulty of cutting them,
and when cut, of detecting their optic axes, evi¬
dently made the research one of extreme labour, yet
highly remunerative, not only through the discovery
of the general principle, but by the vast amount of
beautiful and varied optic displays witnessed in the
course of it. Sir David Brewster was nearly, if not
quite, alone in this research, and after a short resis¬
tance on the part of some mineralogists, his principle
of discrimination of primitive forms of crystallization
by optical characters has been perfectly established.
IY. The action of metals on the light which they
reflect is very peculiar. Malus, who at first believed kaws of
that they were incapable of polarizing it in any ™
gree, afterwards changed his opinion, and inge¬
niously suggested that whilst transparent bodies
reflect, at the polarizing angle, light polarized only in
one plane, metals reflect rays oppositely polarized
and then mixed. Sir David Brewster has the merit
of having, after several unsuccessful attempts, de¬
duced the leading empirical laws of metallic polari¬
zation, having been partly guided (as he states in his
paper in the Philosophical Transactions for 1830)
by Fresnel’s remarkable experiments on circular
polarization produced by total reflection in glass
(see Art. 491). Having found qualities somewhat
analogous in light reflected one or several times from
metallic plates at various angles depending on the
nature of the substance, he gave to the light so re¬
flected the name of elliptically polarized light. It
was afterwards satisfactorily proved by Mr Airy that
the light so named by Sir D. Brewster is in fact
identical in its qualities with the elliptically polar¬
ized light of Fresnel.
The subject of metallic polarization is rather too (534.)
abstruse to be explained in a popular way; and theMetal.1:c
phenomena produced with depolarizing plates of dif-^°^nza"
ferent metals are not so well known as, according to
their discoverer, they deserve to be. My limits only
permit me at present to state that the care and accu¬
racy of Sir D. Brewster’s results are unquestionable;
that they have formed almost the sole data upon
which M. Cauchy and other mathematicians have
based their theories of metallic reflection ; and that,
by generalizing the more limited views entertained by
Fresnel as to the constitution of media and the nature
of reflected light, they have been mainly instrumental
in fixing the later views of optical writers as to the
precise phenomena of polarization as produced, not
only by metals, but by other substances. To these
views I shall briefly advert in the next section.
The laws of the reflection of light at crystallized (53-5.)
surfaces have also been studied by Sir D. Brewster.
In this case observation is still in advance of theory.
V. Of Sir David Brewster’s experiments on the (536.)
absorption of light wre must speak much more Absorption
briefly. White light is coloured or analyzed byofliSht-
refraction (as in a prism); by simple interference, as
in Newton’s rings ; by double refraction combined
with polarization. But it is also decomposed in a
way which, primarily at least, seems different from
all these,—by passing through coloured, or ratner,
colouring media, whether solids, liquids, or gases,
as red glass, ink, chlorine. This, the most familiar
mode of coloration, is the most difficult to account
for, and has been (on account of its obscurity) less
studied than the others. In some instances, the
complementary colour (that which, added to the
transmitted tint, makes up white light) is entirely
absorbed or lost; in other cases it is reflected at or
near the first surface of the medium. Sometimes
(533.)
Chap. V., § 5.]
OPTICS.—SIR D. BREWSTER—FRAUNHOFER.
915
(537.)
Singular
action of
nitrous
acid gas
on light.
(538.)
Fraunhofer
—Lines of
the spec¬
trum.
(539.)
Their num¬
ber and im¬
portance.
the transmitted light is made up of different portions
of the spectrum curiously blended, whilst rays
intermediate in the order of refrangibility are wholly
stifled. Many crystals have the curious property of
dichroism., that is, of transmitting light of different
colours in different directions. All these facts have
been very carefully studied by Sir David Brewster.
But the most remarkable phenomenon to be noticed
under this head is the wonderful action of nitrous acid
gas upon light.1 When abeam, either of sunlight, or
the light of a lamp, is passed through a bottle contain¬
ing a small quantity of fuming nitrous acid, the light
emerges of a tawny orange colour, which may be
deepened indefinitely by heating the acid. If this light
be then analyzed by a common prism, a wonderful
spectacle is seen. The spectrum appears traversed
by countless bands or dark spaces, whilst the blue
and violet colours are nearly absorbed. The effect
of the gas, then, is this,—to stifle or absorb countless
minute portions of light seemingly selected at ran¬
dom from every part of every colour in the whole
spectrum. Some of these deficient rays are broad
and palpable, but most of them are so fine as to be
visible only with the telescope. To understand the
full import of this discovery, it is necessary to
describe first the lines of Fraunhofer.
Joseph Fraunhofer, born in Bavaria, of humble
parents, in 1787, raised himself by his unassisted
efforts to be the first practical optician of the day.
He had also the merit of devoting his leisure and
the fine apparatus at his command to the observa¬
tion and discovery of many optical phenomena, par¬
ticularly those diffractive colours produced by fine
gratings, which are known under the name of Fraun¬
hofer’s spectra.2 His principal discovery, however,
was (in 1814) that of countless deficient or dark
lines in the solar spectrum, resembling those which,
as we have mentioned, were afterwards observed by
Sir D. Brewster, to be produced in any kind of
light by the action of nitrous gas. The deficient rays
of solar light had, indeed, been observed still earlier
(in 1802) by Dr Wollaston, but he counted only a
very few of the more conspicuous ones ; he described
them merely incidentally, and (unusually with him)
seems not to have perceived the great value of the dis¬
covery both in a theoretical and practical point of view.
Fraunhofer’s beautiful map of the spectrum, tra¬
versed by lines of every grade of darkness, and clus¬
tered with every conceivable variety of distribution,
was published in the Munich Transactions. He
counted 590 lines, but Sir D. Brewster states that he
has carried the number to 2000. Like the stars, they
are probably countless. These lines characterize solar
light. The light of the fixed stars and that of the
electric spark have their peculiar deficiencies diffe¬
rent from those of our sun. These were disco¬
vered by Fraunhofer, as well as their occurrence in
certain coloured flames. The order and number
of the lines is, in each case, independent of the
kind of prism used; but the angular distribution
of the deficient rays varies with the material.
Thus an oil of cassia prism expands most in pro¬
portion the less refrangible end of the spectrum ;
while water and sulphuric acid act with dispropor¬
tionate dispersive energy on blue and violet light.
This property of substances had been already studied
by Sir D. Brewster with his usual diligence; but the
importance of Fraunhofer’s discovery was this, that
the lines (the larger of which he distinguished by
letters of the alphabet) furnish landmarks which de¬
fine special rays of light invariably recognisable under
all circumstances, which the vague description of
their tints is quite incompetent to do. This enabled,
on the one hand, the practical optician to discover
the kinds of glass most fit for achromatic combina¬
tion ; and, on the other, it afforded precise numerical
measures of the quality of dispersiveness in bodies
which have been partly already, and will yet much
more become, tests of some of the more obscure and
difficultportions of the theory of light,—those, namely,
which are connected with dispersion and absorption.
Fraunhofer was, after Dollond, the most eminent and
scientific manufacturer of achromatic telescopes, of
which he vastly increased the aperture. He died at
Munich in 1826.
Returning to Sir David Brewster’s discovery of the (540.)
artificial production of analogous lines or deficient ^;ction
rays in light from any source, its importance is easily andTctfthe8
perceived:—for, in the first place, it so far accounts earth’s at-
for the strange phenomenon of the deficient rays mosphere
of the sun’s light, by showing that it may be caused °pe^um
by a gas resembling nitrous acid gas in its proper¬
ties existing in the solar atmosphere ; and, farther,
if so astonishing a result of absorption is ever to be
explained by theory, the first step is to be able to
produce the phenomenon at pleasure, and to examine
the qualities of the bodies producing it. The phe¬
nomena of coloured flames which possess standard
deficient rays, present perhaps a closer analogy to
the sidereal spectra. Sir David Brewster has far¬
ther found that the absorptive action of the earth’s
atmosphere (detected by the varying character of the
spectrum for different angular altitudes of the sun) in¬
creases the number and also the breadth of these lines.
Intimately connected with, and nearly of the same (541.)
date as these experiments, was an observation of Sir
D. Brewster’s, which has received less general assent anaiyg;s 0f
than any other of the numerous and important ones the spec-
. ■    trum.
1 Edinburgh Transactions, vol. xii. (1833).
2 The peculiarity of these spectra is this, that they consist of pure colours, whilst almost all interference-colours are, like those
of Newton’s rings, mixed and impure. One result is very remarkable. Fraunhofer obtained his spectra of such brilliancy as to
be able to measure the position of the dark lines (an evidence of their exceeding purity), thus obtaining & standard spectrum in
which the material of the prism has no influence whatever in varying the ratio of the dispersion of the various colours.
(542.)
His other
scientific
papers.
(543.)
916 MATHEMATICAL AND
which we owe to his genius. It is an analysis of the
coloured light of the (so-called) homogeneous rays of
the pure spectrum by the specific action of absorbing
substances. Sir D. Brewster believes that he has
separated the homogeneous orange of Newton into
red and yellow, the green into yellow and blue; and
that, in fact, each of the three primary colours exists
at every point of the spectrum. But as grave doubts
have been thrown on the results, especially by the
recent careful experiments of Helmholz, I shall not
further insist upon them here.1 Still less can I take
notice of a multitude of microscopic researches on a
variety of objects in the animal, vegetable, and mineral
kingdom, and on the physiology of vision, with which
Sir D. Brewster has filled a multitude of memoirs,
each bearing testimony to the zeal and acuteness by
which his researches are directed.
Sir David Brewster received, in 1816, jointly with
Seebeck, one of the great prizes of the Institute; he
also received, in succession, all the medals in the gift
of the Royal Societies of London and Edinburgh, and
he is an honorary member of the principal academies
of Europe. In particular, he is one of the eight asso¬
ciate-members of the French Academy of Sciences.
To meteorology he has been a valuable contributor,
having discussed in an able paper the law of the
distribution of temperature over the globe, and
pointed out the near coincidence of two regions
or centres of greatest cold in the northern hemi-
sphei’e, with the magnetic poles. His papers are
so numerous, and their variety is so great, as to
render an enumeration, even of those containing what
may reasonably be termed discoveries, impossible
within our limits. Few persons have made with
their own eyes so vast a number of independent
observations ; few have ever observed better, or re¬
corded their observations more faithfully. He has
discovered (as we have partly seen) a multitude of
laws of phenomena of the greatest importance in the
construction of a theory, but he has not been forward
in proposing such a theory. Neither the moveable
polarization of Biot, nor the transverse undulations
of Young and Fresnel, received his cordial assent.
Generally speaking, he has been favourable to a cor¬
puscular theory of light, without, however, attempting
to render the Newtonian view mechanically consistent
with the astonishing variety of complex phenomena
which he aided in discovering, and which would evi¬
dently require it (to say the least) to be completely
remodelled. His scientific glory is different in kind
from that of Young and Fresnel; but the discoverer
of the law of polarization, of biaxal crystals, of op¬
tical mineralogy, and of double refraction by com¬
pression, will always occupy a foremost rank in the
intellectual history of the age.
Before closing this section I shall add a few words
respecting the discoveries of MM. Seebeck and Biot,
PHYSICAL SCIENCE. [Diss. YI.
which have a very close relation to those of Sir David
Brewster.
Thomas Seebeck was born in 1770. We have (544.)
seen that he was one of the discoverers cf the depola- Seebeck.
rizing structure of heated and compressed glass (527).
In 1816 he observed, independently of M. Biot, the
property of oil of turpentine and other fluids to rotate
the plane of polarization of light transmitted through
them, thus acting similarly to a crystal of quartz on a
ray passing along its axis (512). Previously to these
discoveries he had repeated Sir William Herschel’s
experiment on the position of maximum heat in the
spectrum, and found it to vary with the material of
the prism. When the science of electro-magnetism
was created by Oersted in 1819, his attention became
chiefly directed to that class of phenomena, and in
1823 he was fortunate enough to discover thermo¬
electricity. He also wrote many papers on allied
subjects. He was a skilful observer, but deficient in
the power of physical analysis. He died in 1831.
M. Biot, at the time I write, the oldest member f545.)
(I believe') of the Academy of Sciences, and one of Blot—
\ ^ . i-r. - a18 nume-
the veterans ot European science, was born at Pans rous re_
in 1774, and has lived to the age of 80, a life of searches,
almost unintermitted intellectual labour. It is im¬
possible not to be touched by the evidence of such
unconquerable love of knowledge. He was, if I
mistake not, one of the original pupils of the Poly¬
technic School; and his talents being first developed
in an almost purely mathematical direction, he at¬
tracted the notice of Laplace, who introduced him to
the Institute, and by whom he was always befriended.
In 1802 he published a work on curves and surfaces
of the second degree, and was the first after Lambert
who thought of applying mathematics to the theory
of conducted heat. From this time his attention
was almost exclusively directed to the applied sciences,
and the number and variety of his experiments and
writings almost baffles enumeration. Descriptive and
practical astronomy, the theories of sound, of light,
of the voltaic pile, of terrestrial magnetism, of electro¬
magnetism, of heat, radiant and combined, have been
the subjects of his studies and writings. We find him
in the earlier part of his career associated with Gay
Lussac in his first aeronautic expedition, and with
Arago in the geodetical and astronomical operations
of the great arc of the meridian. He afterwards
carried the pendulum to the Island of Unst, the
northmost land in Shetland; and he made original
experiments on the propagation of heat and of sound.
He wrote a voluminous treatise on descriptive and
practical astronomy, one still more elaborate on
general physics, and a vast number of miscellaneous
papers in the Journal des Savans and the Biographic
Universellc. His original memoirs in the Trans¬
actions of the Academy are usually very long and
elaborate, his calculations and empirical formulae
1 See Sir D. Brewster’s statement and defence of his opinions in his Life of Newton, vol. i., p. 117, &c.
Chap. V., § 6.]
OPTICS.—M. BIOT—MB AIRY.
917
laboriously accurate. One of his papers fills an
entire volume of the Academy’s Memoirs. Even
the astronomical hieroglyphics of the Egyptians, and
the chronology of Chinese eclipses, have drawn from
his pen learned treatises; and he has expounded the
labours and discoveries of his countrymen and others
with almost as much care and effort as if they had
been proper to himself. But his subject by predi¬
lection was optics, and here he made his most con¬
siderable discovery, and that which he has followed
out with most minute industry, namely, the rotatory
action of fluids, in which he had Seebeck for a co-dis¬
coverer. (See Art. 512.) He studied the colours of
crystallized plates with exemplary patience, and as
we have seen in the preceding section, by his accu¬
rate observations on the law of the tints, prepared
the way for the theory of transverse vibrations ; but
his owrn doctrine of moveable polarization, which he
imagined to explain them, made no impression on
the progress of science. He was the first who di¬
vided doubly-refracting crystals into positive (as
quartz), and negative (as calcareous spar). In the
former the extraordinary wave is a prolate spheroid,
and inclosed within the ordinary spherical wave ; in
the latter the spheroid is oblate, and exterior to the
sphere. He also discovered (very approximately)
the law regulating the plane of polarization of the
rays in biaxal crystals.
M. Biot has for about half a century been an active (546.)
professor and member of the Institute. His researches,
always marked by precision, are perhaps deficient in
bold conjecture and happy generalization. They are
conducted with a mathematical stiffness which allows
little play to the fancy, and in hypothetical reason¬
ing he rarely indulges. His style is formal yet diffuse,
and consequently somewhat repulsive to the student.
His works are consequently not easily read, and have
contributed less to the progress of knowledge than the
scrupulous care often evinced in their compilation
might seem to warrant. Yet the name of Biot will be
ever associated with devotion to science, and especially
with the progress of optics in our own day.
§ 6. Mr Airy, Sir William R. Hamilton, and Professors Lloyd and Maccullagh.—Confirma¬
tion of Fresnel's Theory—Investigation of the Wave Surface completed ; Conical Refraction.
—M. Cauchy. Mechanical Theory of Elastic Media, and of Ordinary and Metallic
Reflection; M. Jamin.—Theory of J)ispersion; Professor Powell.
(547.) It would not be possible, in one short section, to
Progress of(j0 justice to the various improvements and additions
Lory the-" t^e undulatory theory of light—the joint crea-
ory since tion of Huygens, Young, and Fresnel—has received
Fresnel, since the nearly simultaneous decease of the two last-
named philosophers. But while a vast amount of
labour and of mathematical and experimental skill
has been thus expended, of which it would be in vain
to attempt within our limits to give an account, we may
pause upon two or three of the more conspicuous re¬
sults of these researches, which, in conformity with
the plan of this dissertation, may give a tolerable
idea of their general tendency.
(548.) Looking at the history generally, wre find one cu-
Pecuhan- rious peculiarity in the progress of this remarkable
history. theory. Its origin in the seventeenth century was
unattended with sympathy or success. It received
little support, and was well nigh forgotten for more
than an hundred years: it was then resumed (we might
almost say re-invented) in England, but it remained
unpopular and almost unknown until re-echoed from
a foreign land ; while in France itself the views of
Fresnel were (with one or two exceptions) as little
appreciated as those of Young had been in England.
From this period England became the place of its
chief development; and with the exception of one
eminent philosopher, M. Cauchy, its supporters and
extenders, whether by analysis or experiment, have
belonged to Great Britain,1 a few of the most conspi¬
cuous of whom are named at the head of this section.
The attention of the British public was forcibly (549.)
called to the theory of Young and Fresnel, by an Sir J-Heiv-
able treatise on Light, contributed by Sir John^e^"d
Herschel in 1827 to the Encyclopcedia Metropolitana.
The excellent method, lucid explanations, and intel¬
ligent zeal which marked this essay compelled the no¬
tice of men of science, too long deterred from the study
of the fragmentary and abstruse writings of Young.
It was followed four years later by a most able and
precise mathematical exposition of the theory, and its
application to optical problems, by Mr Airy (now As¬
tronomer Royal), who vras then Plumian Professor at
Cambridge, and who introduced this part of optics
as a branch of study in that university. Whilst the
excellent tract on the undulatory theory (published in
1831 in his Mathematical Tracts) opened up the
subject in a most accessible form to British mathe¬
maticians, his original papers in the Cambridge
Transactions confirmed the doctrines of Fresnel by a
number of newr and admirably contrived experiments,
some in connection with interference, some with po¬
larization, and all were confronted with the rigorous
results of the mathematical theory. The paper on
Quartz, and that on the Rainbow, have been already
referred to (art. 466, 512). The writings of Mr Airy
and of Sir John Herschel have continued to be the
1 M. Moigno (a Frenchman), writing in 1847, laments that France was then perhaps the only country in which the experiment
of “ conical refraction” (the triumph of Fresnel’s theory to be presently mentioned) had never been repeated.
918
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
main sources of information on this subject, and on phy¬
sical optics generally, not only in this country but on
the Continent. It is remarkable that in I ranee, which
possesses so many admirable scientific books, there
should not exist a single good treatise on optics.
Had not Mr Airy’s attention been necessarily with¬
drawn from optics to astronomy, it is very evident that
the theory of light would have received from him
many farther important additions.
(550.) Whilst an impulse was thus given to the mathe-
Sir Wm: matical theory of light in the University of Cam-
ton andDr bridge, a similar progress was being made in the
Lloyd. sister University of Dublin, where three of her most
eminent professors, Sir William Rowan Hamilton
and Professors Lloyd and Maccullagh devoted
themselves energetically to its improvement and veri¬
fication.
(551.) To the two former of these we owe the prediction and
Conical re- ocular demonstration of the most singular and critical
bTaxal*11 ^ results °f Fresnel’s theory. Sir William
crystals. Hamilton, a geometer of the first order, having un¬
dertaken the more complete discussion of the wave
surface of Fresnel (see Section Third of this Chapter),
to the equation of which he gave a more elegant
form than heretofore,1 ascertained the exact nature
of that surface, and consequently the exact direction
of refracted rays in the neighbourhood of the “ optic
axes.” It had been shown by Fresnel that, in the case
of crystals with two axes, a plane section in a certain
direction cuts the two sheets of the wave surface in
a circle and in an ellipse, which necessarily intersect
each other in four places. (See the annexed figure.)
In the lines joining these four points with the centre
of the figure the velocity of the two rays is equal.
Now the cusps or sharp inflections of the wave surface
in these particular directions, occur not only in the
particular plane of section which we have considered,
but in any section of the wave surface passing through
these lines of equal ray-velocity. In the figure, there¬
fore, of the compound sheet there is not tx furrow, as
Fresnel had supposed, but a pit or dimple, with
arched sides something like the flower of a convol¬
vulus, and the surfaces meet at the bottom of the pit
at a definite angle. Let the circle and ellipse,
in the annexed figure, represent the section of the
wave surface we have described ; then 0 P is the line
of uniform propagation, and P is the bottom of the
conoidal pit M P N. Now
suppose a slender ray of light
to move through the crystal in
the line 0 P, and to emerge
into air at a surface of the
crystal cut perpendicular or
nearly so to the direction of
single ray-velocity 0 P. If we
confine our attention at first to
the plane of the figure only,
that ray having intersecting
tangents both proper to the wave surface, would
give rise, on Huygens’ construction (art. 475), to two
emergent rays inclined at an angle. But since this
is the case, not only in the plane of the figure, but
(as has been stated) in any plane passing through
the ray in question, the emergent light must form a
conical luminous sheet, the angle of the cone being
determined by the refractive properties of the crystal.
This beautiful and unexpected result was verified with
great skill and address by Dr Lloyd in the case of
Arragonite, which is a biaxal crystal, and he found
the position, dimensions, and conditions of polariza¬
tion of the emerging cone of light to be exactly such
as theory assigns. When all the necessary correc¬
tions are attended to, the angle of the cone of light
is about 3°. There is another case of conical (or it
might be called cylindrical) refraction, which occurs
nearly in the same portion of a crystal, which was
predicted and discovered in like manner, but which
we will not stop to particularize.2 The observations
of Dr Lloyd have been extended by M. Haidinger to
the case of Diopside, a crystal also having two optic
axes.
Every one capable of appreciating such evidence, (552.)
will feel the irresistible impression which so curious Other
an anticipation, so accurately fulfilled, gives us of the
positive truth of a theory admitting of such veri-milton an(i
fications. The names of Sir W. Hamilton and Dr Dr Lloyd.
Lloyd will be handed down to posterity in connec¬
tion with this admirable discovery. But they have
also other claims to our respect, to which we can
here only refer in the most general terms. The for¬
mer has generalized the most complicated cases of
common geometrical optics by a peculiar analysis de¬
veloped in his essays on “ Systems of Rays” (Irish
Academy Transactions, vols. xv.-xvii.)3 To Dr Lloyd
Quater¬
nions.
i>V
= o.
1 The equation is— -g-—0 , » + „ , „ , ,, 2 .
1 a:J + jr + — cr ar + jr + ^ — oJ a;-2 + Jf + — c
2 It was shown by Sir W. Hamilton that the tangent plane M N touches the wave surface, not in two points merely, but in a
circle of contact; consequently, the perpendicular to this tangent plane, OM, is the direction of one of the optic axes (or the velo¬
city is the same for both portions of the compound wave). Hence a ray incident externally so as to be refracted along this perpen¬
dicular, will at entrance spread into a hollow cone interior to the crystal, and on emergence at a parallel face each portion of
the ray recovers a direction parallel to its primitive direction, and a luminous hollow cylinder is the result. See Dr Lloyd, in
the Irish Academy Transactions, vol. xvii., and Sir W. R. Hamilton’s third supplement to his “ Systems of Rays” in the same vol.
3 Sir W. R. Hamilton is also a discoverer in pure analysis and its connection with geometry. Following up the ideas of Mr
Warren on the geometrical significance of the symbol \/ — 1, as indicative of direction, Sir W. Hamilton has developed the theory
of a new class of imaginary quantities, which he terms quaternions, by means of which he contrives to express simultaneously
the direction in space and magnitude of a line or form ; and this calculus he has applied to the solutions of problems of geometry
and physical astronomy. The quaternion appears to express something even beyond this ; and this redundancy has been consi¬
dered as a difficulty by some mathematicians. The superfluous number is considered by Sir W. Hamilton as representing time
in mechanical problems.
Chap. V., § 6.]
OPTICS.—MACCULLAGH—M. CAUCHY.
919
we are indebted for several interesting experimental
papers on optics, for an able and impartial review
of the progress of the science,1 and for an excellent
elementary treatise on the Wave Theory, which forms
by far the best popular introduction to the subject.
(553.) Closely associated in his pursuits, as in personal
Maccul- friendship, with Sir W. R. Hamilton and Dr Lloyd,
lagh- was James Maccullagh, a native of Tyrone, born in
1809, and who died prematurely and unhappily Oc¬
tober 24, 1847.2 His first paper was communicated
to the Royal Irish Academy at the age of 21. It
was one of the earliest original contributions of this
country to the development of the theory of Fresnel.
The construction of the wave surface in biaxal crys¬
tals was simplified and improved ; and in 1835 a
second paper appeared, in which geometrical construc¬
tions of great elegance were employed for the farther
investigation of the subject. Mr Maccullagh next at¬
tacked the theory of the undulations of ether in quartz
crystals, to which he gave a mathematical expression
(see art. 512). In 1838 he published a paper on the
laws of crystalline reflection, in which he adopted
certain hypotheses, such as that the vibrations of the
ethereal particles, in the case of polarized light, are
parallel to the plane of polarization (contrary to Fres¬
nel’s opinion), and that the density of ether is the same
in all media. In a subsequent memoir on the dyna¬
mical theory of reflection and refraction, he arrived
at similar results with fewer physical assumptions,
and by a more purely mathematical treatment of the
subject. Subsequent researches, presently to be men¬
tioned, have diminished the value of these theoretical
investigations.
(554.) Numerous mathematicians of eminence at home
theories1 of1 an<^ a^roafl entered upon the same arduous enquiry,
vibratory To attempt to deduce from the hypothetical constitu-
motion. tion of a very rare highly-elastic medium, together
with the known dynamic laws, thevarious complicated
facts of optics, was a problem whose difficulty was only
equalled by its indefinite character. For how little
do we know of the molecular constitution of such
fluids as air and water ? How much less then of a
fluid (if we may so term it) almost infinitely rarer, and
incapable of being inclosed, measured, or weighed ?
The bare possibility of transversal undulations was
long contested by very able mathematicians ; and con¬
ceding it, the mutual influence of such an ether and
the particles of gross matter (as shown by reflection
and refraction) must, it would seem, for ever remain
problematical. Yet, however gratuitous or even er¬
roneous our reasonings about such ultimate questions
may be, there is no doubt a real benefit in obtaining
from them at least a mathematical congruity with ob¬
served facts. The progress of science shows that
there is a practical usefulness in this step. On the
other hand, we must not be discouraged to find
that there are so many handles to the matter, that
even the most profound thinkers may conceive that
they have reached the proposed end by different and
incongruous routes. Besides the mathematicians
whom I have mentioned, many others were in the
field; for the result of tremors propagated through
elastic media of different kinds is an enquiry of ex¬
cessive generality, and forms a part of many branches
of science besides optics. MM. Cauchy, Navier,
Poisson, Coriolis, Green, Kelland, and Neumann are
amongst those who attacked the problem. For a series
of years memoirs rose fast and thick on this favourite
battle-field; and even a skilful mathematician might
find it no small penance to discuss the merits of the
various hypotheses and the solidity of the respective
deductions which were proposed.
It must be owned that a great part of this vast (555.)
mathematical toil has been without immediate result
in optics. It is by comparing the conclusions ar-tics. *
rived at by authorities of seemingly equal weight, that
we learn the difference between a stable physical in¬
duction and a clever mathematical hypothesis. Mac¬
cullagh, for instance, maintains the vibrations of ether
to be parallel to the plane of polarization; Fresnel
and M. Cauchy3 that they are perpendicular. The
first mathematician considered that the vibrations are
wholly transversal, the last believes that the normal
vibrations have also their share in affecting the
phenomena, whilst Poisson denies that transversal
vibrations can be propagated to a sensible distance.
Maccullagh finds that, to account for metallic reflec¬
tion, the indices of refraction of mercury and silver
are 15'0 and 35-0, whilst Cauchy makes them but
1-77 and (P34. One theorist assumes that the
density of ether is the same in all bodies, another
that it is greatest in a vacuum, and others pre¬
cisely the reverse ; one that vibration is not accom¬
panied by change of density, another that it is ;4
and so on in almost endless variety. A matmred
opinion can only be formed after the results of the
various assumptions, and their congruity with facts,
have been more thoroughly worked out. Already
two of Maccullagh’s essential postulates have lost
much of their plausibility ; that respecting the di¬
rection of the vibrations in polarized light has been
probably decided by Professor Stokes in favour of
Fresnel’s opposite view, by an admirably devised ex¬
periment on the effect of diffraction on polarized
1 British Association Reports for 1834.
2 It is unnecessary to suppress the fact that Mr Maccullagh died by his own hand, under the pressure of a fit of despondency,
brought on (it is believed) by over-work ; a fate happily extremely rare amongst students of exact science. I say it is needless
to suppress the fact, because it infers no blame. Mr Maccullagh was an amiable, pious, and exemplary man. Irresponsible in¬
sanity was, of course, the cause.
3 This is M. Cauchy’s last view • for some years he adopted the opposite one, which he then surrendered with great frankness.
4 If, however, the vibrations were wholly transversal, it seems to be admitted that they would not affect the density of the medium.
920
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
rays 1; the existence of normal vibrations seems to
be proved by the ingenious experiments of M. Jamin,
showing that at no angle is light perfectly polarized
by reflection. The more we see of these diversities
arising in the progress of science, the less are we
disposed to found on merely mathematical conclu¬
sions from an assumed constitution of elastic bodies ;
the more, on the other hand, do we admire the ad¬
mirable sagacity of Fresnel—the real Newton of
modern optics—few of even the least of whose sug¬
gestive anticipations have fallen to the ground.
(556.) M. Augustin Louis Cauchy has been long known
M. Cauchy as one 0f the ablest and most prolific mathematical
mathemati- wr'ters of this century. Besides numerous and im-
cal labours, portant memoirs, on nearly every branch of pure
and applied mathematics, published in the Journal
de VEcole Polytechnique, and the Memoirs of the In¬
stitute, he has published, in a separate form, Exer¬
cises des Mathematiques in two series of volumes;
and for many years scarcely a weekly meeting of the
Academy of Sciences occurred without a mathema¬
tical memoir of this prolific author being laid on the
table, and subsequently printed in the Comptes Ren-
dus. The integral calculus and other parts of ana¬
lysis form the subjects of a large part of these writings;
but the theory of hydrodynamics in the earlier, and of
optics in the later part of his career, are largely re¬
presented. So diffuse and desultory a mode of publi¬
cation has been little favourable to those who wish to
make themselves acquainted with what has been ac¬
complished by M. Cauchy. The scientific world is in¬
debted to Abbe Moigno2 in France, M. Radicke3in
Germany, and Professor Powell4 in England, for ana¬
lyzing in part his optical labours. As the present
brief notice is evidently inadequate to include even
the most superficial view of the whole, I shall say a
few words upon two of his theoretical researches on
light, which have attracted most general attention.
The first is upon the theory of Reflection and Re¬
fraction, framed so as to include the phenomena of
metallic reflection ; the second is upon the Dispersion
of Light.
(557.) I shall first mention some seemingly exceptional
facts to the ordinary laws of polarization by reflec- Theory of
tion. As early as \Q\4: ^Philosophical Transactions, re^ecilon
1814, p. 230), Sir David Brewster had remarked that tbn.Tn-^*
such highly refractive substances as Realgar, Diamond, eluding the
and Chromate of Lead, do not polarize, at any angle, case of
the whole of the reflected light. Mr Airy afterwards meta*s'
showed that light reflected from diamond near the
maximum polarizing angle, possesses qualities re¬
sembling those of light reflected from metals. The
same view was more generally stated by Mr Dale;5
and last of all, M. Jamin showed that all transparent M. Jamin.
substances polarize elliptically the light which they
reflect,—the difference of “phase ” of the two compo¬
nent vibrations increasing from 180° at a perpen¬
dicular incidence, to 360° at an incidence of 90° ; and
that the laws of reflection at transparent surfaces, as
also in the case of metals, depend upon two con¬
stants—the index of refraction and the coefficient of
ellipticity. And he has determined in numerous
cases the values of these constants.
Thus Fresnel’s theory of reflection requires un- (558.)
doubted modification. It only holds true for sub- ^resnel’s
stances whose index of refraction is nearly 1-46, that <iified by
of the glass which he examined. The complication Green and
is held to arise from the existence of vibrations byM>
(called normal) in the direction of transmission of the <-;auchy'
luminiferous wave, such as those which produce the
effects of Sound in air, and which produce certain
effects on Light at the bounding surfaces of two
media. In the theory of Fresnel, as also in those of
Maccullagh and Neumann, this influence is neglected.
To Green and to M. Cauchy belongs the merit of lay¬
ing down a more comprehensive theory. Mr Green’s
theory, published in 18376 (not long before his death),
is so far incomplete that it involves only one constant.
M. Cauchy’s investigations, published two years later,7
embrace the phenomena of metallic reflection by the
introduction of the two constants mentioned above,
thus completing the theory of reflection and refrac¬
tion both for transparent and metallic surfaces.
The fact of the unequal refrangibility (dispersion) (559.)
of light has ever been felt to be one of the most dispersion,
real as well as prominent difficulties in admitting
2 Repertoire d'Optique Moderne. 1847-50.
4 The Undulatory Theory as applied to the Dispersion of Light. 1841.
1 Cambridge Transactions, vol. ix.
3 Handbuch der Optik, Band i., 1839.
6 See Moigno Rep. d'Optique, p. 1385.
Green’s . 6 Cambridge Transactions, vol. vii. The following extract from this able paper shows the independence of physical assump-
accour.t of ^ons which characterizes these ultra-mathematical optical theories :—“ . . . We are so perfectly ignorant of the mode of action
his method. °^. ^.e e^emeni's lununiferous ether on each other, that it would seem a safe method to take some general physical [?]
principle as the basis of our reasoning. . . . The principle selected as the basis of the reasoning contained in the follow-
ing paper is this: In whatever way the elements of any material system act upon each other, if all the internal forces exerted
be multiplied by the elements of their respective directions, the total sum for any assigned portion of the mass will always be
the exact differential of some function. But this function being known, we can immediately apply the general method given in
the Mecanique Analytique, and which appears to be more especially applicable to problems that relate to the motions of systems
of an immense number of particles mutually acting on each other. One of the advantages of this method, of great importance,
is, that we are. necessarily led by the mere process of the calculation, and, with little care on our part, to all the equations and
conditions which are requisite and sufficient for the complete solution of any problem to which it may be applied.”
A consideration of the candid admissions of the preceding paragraphs (especially the last sentence) will lead the reader to see
ow short a way a theory of so general a kind—the chief characteristic of which consists in eluding every troublesome physical
enquiry can go towards explaining the relations of Light to Matter; yet it may be of use by indicating the kind of solutions
w ich more restricted hypothesis may be expected to give of the laws of phenomena.
Comptes Rendus de VAcad, des Sciences.
Chap. V., § 7-]
OPTICS.—M. CAUCHY—RITTER.
921
the undulatory theory. That theory, in its simple
form, enables us indeed to explain clearly enough
the refraction of light owing to a change of velocity
m the wave as it passes from one medium to an¬
other ; but it assigns no reason wdiy that change of
velocity should be different for light of various co¬
lours, in other words, of different wave-lengths. The
corpuscular theory, on the other hand, furnishes at
least a plausible explanation, by assuming a variable
attraction between refracting media and the mole¬
cules composing the different rays.
(560.) When, however, undulationists were pressed on
on the fi- subject, it was easy to see the direction in which
nite dis- at least a plausible explanation might he sought. In
tances of the usual form of equation for vibrations in air,
ing par-at' ^ven by Lagrange, the integration is effected by as-
ticles. suming the intervals between the particles evanescent
compared with the length of a wave. This is per¬
fectly true in the case of sound, and all sounds ap¬
pear in consequence to travel uniformly. But should
it fail in the case of light, that is, should the inter¬
vals of the ethereal particles bear some sensible ratio
to that very small quantity, the length of a wave,
what would be the result ? M. Cauchy has made
out, by a very complex analysis, that in this case the
longer waves will travel most rapidly, and conse¬
quently be least refracted. Several other writers,
especially Professor Kelland, obtained similar re¬
sults; and Mr Airy, by very simple, though only
approximate, considerations, showed the dependence
of refraction on the length of a wave.1 M. Cauchy’s
memoir appeared in 1835 at Prague, in a bulky and
abstruse form: the mathematical investigations are
very long and complex, the numerical verifications
scarcely less so.2 The indices of refraction, observed
by Fraunhofer, for different lines of the spectrum, in
different kinds of glass, together with the correspond¬
ing wave-lengths for these rays, formed the principal
data for comparison. But others have since been
obtained by Rudberg and Professor Powell, and care¬
fully compared with M. Cauchy’s theory by the lat¬
ter, and the coincidence appears satisfactory.3 But
in estimating the value of this coincidence, it is to
be observed that of 7 indices of refraction observed
for each substance, 3 must be used to ascertain the
constants in the formula, and only 4 remain to be
calculated.
One difficulty, however, remains. If the rays of (561.)
light travel through space with variable velocities, the Ne°rg(dis' f
images of the stars would present tails of colour in- fighun °
consistent with observation. M. Cauchy eludes this free space,
difficulty by the following hypothesis respecting ethe¬
real media :—The existence of transversal vibrations
(according to him) requires that the law of force be¬
tween particle and particle of ether must not be inter¬
mediate between the inverse 2d and inverse 4th power
of their distance. In the former case the force is an
attractive, in the second a repulsive one. In the first,
the velocity of propagation depends on the length of
a wave, in the second it is independent of it. [The
first case, too, alone will be consistent with perma¬
nent longitudinal vibrations.] Consequently if we
suppose that in free space the particles of ether are
arranged in close order, and exert a repulsive force
on each other, no dispersion results; but in refract¬
ing media, supposing the distance of the molecules
increased, and the mutual action attractive, then dis¬
persion occurs.4
§ 7. Ritter.—Chemical Rays of the Spectrum.—Niepce ; Daguerre ; Mr Talbot. Art of Helio-
graphy or Photography—Daguerreotype—Calotype.—Professor Stokes. Chemical Rays ren¬
dered visible—Fluorescence.
(562.)
Chemical
action of
light.
A very curious chapter of the history of Light re¬
mains to be written, respecting the chemical ener¬
gies which itis capable of exerting, or which at least are
found in those parts of the solar rays which are dispersed
by a prism. These are in part luminous and partly
invisible under ordinary circumstances, the latter pos¬
sessing these chemical qualities in a still higher degree
than the others. Though not perhaps very closely
associated with the optical discussions of the previous
sections, it seems impossible to separate this part of
the subject from the rest, since the rays called Che¬
mical may, as we have reason to think, be reflected,
refracted, polarized, absorbed, and made to interfere
like visible light; and farther, because to the extreme
limit of their sensible action they may, by certain
treatment, be made visible to the eye. The art of
photography, though belonging quite as much to che¬
mistry as optics, being a means of inquiry into the
qualities of the solar radiations invaluable to the
natural philosopher, cannot byanymeans be excluded
from a sketch, however general, of the progress of
physical science.
J. W. Ritter, Professor of Chemistry at Jena, (563.)
and well-known for his numerous contributionsRitter-
to the earlier progress of voltaic electricity, has
the merit of having first clearly pointed out in 1801
the separate existence of chemical rays in the spec¬
trum which extend beyond the most refrangible or
1 In all these cases the expression for refrangibility depends on the ratio of the sine of an arc to the arc itself; which are
again includes the ratio of Ax, the distance of the molecules to A, the length of a wave. When Lx becomes very small, the first
ratio becomes unity.
2 A portion of these researches had, however, been printed in Paris (privately, I believe) in 1830.
3 Powell on the Undulatory Theory. 1841. 4 Moigno, Repertoire d'Optique, p. 128.
VOL. I. 6 A
922
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
violet rays (when the sun’s light is decomposed by a
prism), in the same manner as the invisible rays of
heat were found by Sir Wm. Herschel to extend be¬
yond the visible red. Scheele had indeed previously
noticed that the power of the sun’s light to decom¬
pose and blacken salts of silver increased rapidly
from the red towards the violet ray; and there is little
doubt that Herschel’s discovery suggested that of
Ritter, of the independent or non-luminous rays of
the spectrum.
(564.) Ritter attributed to these rays a deoxidizing qua-
~he j)r Wollaston, who also made experiments on
spectrum, the subject, and discovered the specific action of the
different rays on gum-guiacum, prudently suggested
the more comprehensive term of chemical rays. Va¬
rious other denominations have been proposed, which
need not be here dwelt upon; all that can be said is,
that deoxidation does not represent the solar action
completely. Whether it be really an independent
principle in the sun’s rays which causes these effects,
or merely light and its modifications, is, as in the
corresponding case of heat, yet undecided. But it
is remarkable that, as shown by M. E. Becquerel,
the discontinuity of the luminous spectrum produc¬
ing “Fraunhofer’s Lines” exists equally for the che¬
mical rays.
(565.) Soon after Ritter’s first experiments, Dr Young
They m- pr0yed the Interference of the obscure chemical
and may berays {Phil. Trans., 1803), a conclusion successively
polarized, claimed since by different physicists. Berard in 1812
showed that these rays are polarized by reflection.
Seebeck observed that the different rays impressed
different colours upon salts of silver: and M. Edmond
Becquerel long afterwards showed that the red and
yellow rays, though incapable of commencing chemical
action, in some instances have the power of continu¬
ing it when once excited by the more refrangible
rays.
(566.) In 1835 Mrs Somerville made some interesting
Mrs So-, experiments on the permeability of different bodies
merville s cpemjca} rays, similar to those of Melloni on
ments. the heating rays (see chap. YI., § 8), and she found
great and seemingly capricious variations in this re¬
spect.1 The account of them was addressed to Arago,
and published in the proceedings of the French Aca¬
demy. She found that green glass, coloured by cop¬
per, intercepted entirely the chemical rays, yet this was
not due so much to its colour as to its other qualities
(which are also peculiar as regards i-adiant heat), for
the emerald transmits the same rays. Red glass
stops most of the chemical rays, whilst the garnet
transmits them. Though white glass has generally
been considered very transparent for these rays, Mr
Stokes has shown that it entirely stops those of the
very highest refrangibility, which are readily trans¬
mitted by quartz. Sir John Herschel and Mr Hunt
have made many interesting experiments with coloured
media on the particular parts of the chemical spec¬
trum absorbed, but a great deal remains to be done,
especially as regards the nature of the substances
employed.
But the great impulse given to this subject was (567.)
derived from the invention or discovery of the beau- j^otogra-f
tiful art of Photography. phy.
In 1802 Mr Thomas Wedgewood and Sir Hum- (568.)
phrey Davy succeeded in forming pictures of objects ^0e0^g^d
laid on paper prepared with nitrate of silver, and in DaVy.
taking profiles (silhouettes') by means of shadows.
They proposed to obtain similar effects by means of
the camera obscura, but their paper was not suffi¬
ciently sensitive. The effectual bar to their proceed¬
ings was, however, this: that they could discover no
means of fixing the shadows which they had ob¬
tained, or preventing the whole surface of the paper
from being gradually blackened by exposure to light.
In 1814 J. Nicephore Niepce, a retired proprie- (569.)
tor at Chalons sur Saone,2 entered into a similar en- ^g6^01,6
quiry, but by methods quite different. He employed ^iep
the solar effect upon resinous bodies, and some
at least of his pictures were executed on plates of
pewter or of rolled silver. They were mostly copies
of engravings, and the light parts corresponded to the
lights of the originals. He, however, at length suc¬
ceeded in fixing impressions of vieAvs in the camera
obscura, though in an imperfect manner, and after very
long exposure. The pictures thus obtained had this
in common with more perfect processes, that the lu¬
minous impression was first brought into view by
a chemical process subsequent to exposure in the
camera. In 1825 Nicephore Niepce became associated
with Daguerre, who had previously been engaged in Daguerre,
the same research ; they agreed to communicate the
results of their several experiments. The result, as
is well known, was the invention of the Daguerreo¬
type, not improperly called after Daguerre, who
seems really to have worked it out almost entirely
for himself, after the death of Niepce in 1833;
whilst so patient and determined was Daguerre in
Mrs Mary 1 The maiden name of this accomplished lady was Mary Somerville ; she was born, I believe, at Jedburgh, and married first Mr
Somerville Greig, afterwards her relative Dr Somerville. She is known in British science not only as the able commentator of Laplace’s Meca-
— magne- nique Celeste, but as the author of some ingenious and apparently convincing experiments on the magnetizing power of the violet
tic action ray. Some anomaly, however, remains to be explained on this subject, as the result cannot always be obtained. Several years
of light [?]. before Dr Faraday made his discovery of what he terms the “ magnetization of light” (see chapter vii., § 5), the writer of
these pages supposed that the reaction of light and magnetism, observed by Morichini and Mrs Somerville, might be due to a la¬
tent and casual polarization of the light which was not present in all the experiments ; and, in particular, he suspected that circu¬
larly polarized light might have a magnetic influence; but his experiments to this effect, in May 1836, were not successful,
though he thinks them worth repeating.
3 Probably one of the MM. Niepce who, in the early part of the century, are said to have propelled a boat on the Saone by a
peculiar kind of air-engine, called pyreolophore. Delambre, Rapport Historiqtie, 1810, p. 242.
■DAGUERRE—MR TALBOT.
923
Chap. V., § 7.] OPTICS (PHOTOGRAPHY).—
(570.)
The da¬
guerreo¬
type.
(571.)
Mr Fox
Talbot—•
the calo-
type.
keeping his secret until brought to perfection, that
he did not even show his results until early in 1839,
when the numerous specimens he had to exhibit ri¬
valled in delicacy anything that the art has since
produced.1
The daguerreotype is depicted in the camera on a
plate of silver, coated with an evanescent film of
iodide, by exposure for a short time to the vapour of
iodine. After the light has acted, and the plate has
been withdrawn from the camera, no trace of a pic¬
ture is visible until it has been exposed to the vapour
of mercury, which, by its peculiar action on the places
where light has acted, produces a correct picture of
the object (or 'positive image, as it is called, light an¬
swering to light). It is then fixed, as it is called, by a
bath of dissolved hypo-sulphite of soda, which has
the property of removing the iodide of silver wherever
the light has not acted. This singular and elaborate
process has since been but slightly modified by vari¬
ous plans for rendering the iodide more exquisitely
sensitive. To M. Niepce belongs the credit (1) of
having fixed an impression of light, (2) of using
metal plates, (3) of forming a picture by means of a
camera obscura ; to Daguerre, on the other hand,
the novel and ingenious use of vapours instead of
washes, and the whole succession of operations in
the daguerreotype. When the French government
acquired for the public (the French public, however,
only) a right of property in the invention, they
marked their sense of the share of merit of the in¬
ventors, by awarding to Daguerre 6U00, to M. I.
Niepce 4000 francs per annum.
Mr W. H. Fox Talbot, a Wiltshire gentleman
of great ingenuity and perseverance, and well ac¬
quainted with mathematics and physics, applied him¬
self in 1834 to the problem of fixing shadows, in
entire ignorance of what Wedgewood and Davy had
attempted. He used paper washed with the nitrate
of silver, and soon succeeded in obtaining impressions
of lace and leaves of plants, but without fixing the
shadows. This great step he, however, made a
year or two later : a wash of iodide of potassium,
or of common brine, was found to effect it. The
announcement of his success and of his methods
was called forth early in 18392 by the first reports of
Daguerre’s discovery. His method then consisted in
dipping writing paper alternately in nitrate of silver
and common salt, drying between the operations,
and afterwards fixing the image. An unnatural or
negative picture was thus obtained, the lights of na¬
ture being darkened on the paper, and vice versa;
but the truth was restored by pressing the drawing
thus obtained against a second prepared sheet of
paper, and exposing it to light, when the natural
lights and shades were of course obtained. This
derived impression is called a.positive. This process
has evidently several advantages over Daguerre’s ;—
such as, that paper is used instead of metal plates ;
and that from a single impression (negative from
nature) copies may be at leisure indefinitely multi¬
plied. Pictures were thus obtained by Mr Talbot
with the camera obscura.
Mr Talbot’s chief improvement on his first me- (572.)
thod he called the Calotype (1841), and consisted in Progress,
washing the paper successively with nitrate of silver,
iodide of potassium,3 4 and gallo-nitrate of silver. It
is then exposed in the camera, but no impression
appears until again washed with the gallo-nitrate of
silver. It is then fixed with bromide of potassium, or
with hypo-sulphite of soda, as in Daguerre’s process.
By a subsequent invention, Mr Talbot has obtained (573.)
what he iustly calls an instantaneous process} An Instanta-
image was formed m a camera of a revolving wheel, cegg 1
to which was affixed a printed bill; the room being
darkened, and the wheel made to revolve with the
speed of 200 revolutions in a second, and being then
illuminated by an electric spark, a legible impression
of the printing was obtained. We doubt if, in the
whole history of physics, a more astonishing result
is recorded. Thus Mr Fox Talbot, by his rare energy,
brought his inventions almost to perfection. Nume¬
rous competitors, of course, appeared on the field, and
obtained many interesting results. The only one of
much importance to the art of photography is the
substitution of a film of iodized collodion on a glass
plate, for the prepared paper in the first or negative
process.
The daguerreotype and calotype processes, though (574.)
seemingly so different, have much in common :—(1) Analogy
a sensitive surface has to be prepared (iodide of silver proceJ^0
is the basis in both) ; (2) it is exposed in the camera ;
(3) the picture (still invisible) is developed; (4) it is
fixed. In the calotype the printing process for ob¬
taining positives must be added to these.
The chemical theory is very far behind the art of (575.)
photography. The most important steps of these Chemical
curious and complicated processes have been at-perfect1"1"
tained by a kind of divination after a multitude of
failures. The salts of silver are of a highly de¬
composable nature, the iodides and bromides pecu-
1 The present writer had the benefit of seeing Daguerre’s marvellous productions, and making his acquaintance at Paris,
through the courtesy of M. Arago, while the secret was still preserved, and the public interest was excited to the highest pitch.
About the same time he saw M. Isidore Niepce, son of the first photographer, and the specimens in his hands, as well as those in
the possession of Mr Bauer of Kew, with whom they had been left by M. Nicephore Niepce, when he visited England in 1827
and exhibited them at the Royal Society. One of the latter was engraved on a plate resembling pewter.
2 Communicated to the Royal Society of London, 31st January, and printed in the Philosophical Magazine for March.
3 Mr Talbot says (Phil. Mag., March 1839, p. 203) that Sir H. Davy had recommended iodide of silver as a sensitive substance ;
but in his earlier experiments he had found it the contrary. But now, like Daguerre, he requires no immediate visible action
of light, but developes it by a subsequent reaction.
4 The process is described in Hunt's Researches on Light, 2d edit., p. 140.
924
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
liarly so. The action of light appears to be to reduce
the metallic silver, at least partially, an operation
which is completed in the daguerreotype process ap¬
parently by the affinity of the mercurial vapour for
iodine and for oxygen.1
(576.) If anything were wanting to show the impossibility
Importance 0f separating the scientific arts from the history of
of the pho- gcjence itself) it would be the case before us. The
apgiap ic Gt‘ p]aotography is far in advance of the theory,
yet it constitutes in itself the greater part of what
we know in a highly interesting branch of Natural
Philosophy—the chemical agency of the spectrum.
The surfaces of Talbot and Daguerre are the philo¬
sophical tools by which farther discoveries can alone
be made.
(577.) So intimately connected with the discovery of the
Chemical Chemical Rays of the spectrum, is that of revealing
rays ren- £]lcjr existence (at least the existence of rays of the
sible. spectrum equally refrangible with those possessing
chemical properties) to the sense of sight, that we may
conveniently include in this section a very brief no¬
tice of Professor Stokes’ remarkable experiments.
(578.) Mr George Gabriel Stokes, a fellow of Pembroke
Stakes801" Ccffic§'e> Cambridge, and senior wrangler in 1841,
at present holds the distinguished position of Luca¬
sian Professor of Mathematics. It is almost need¬
less, therefore, to state that his mathematical talents
are generally acknowledged, and that he has dis¬
played them by a ready application to many difficult
problems in optics and mechanics which had not pre¬
viously been accomplished. I may refer, however, to
the integration of complex differential equations oc¬
curring in the theory of the flexure of solids (see art.
364), and in that of the rainbow (466), and in his
elaborate investigation of certain cases of the friction
of fluids (416). But it is more to our present pur¬
pose to observe that he combines this profound and
technical command of analysis with singular skill in
the experimental department of optics ;—not merely
in investigations closely connected with the wave
theory, and expressible by mathematical formulse,2
but in those which depend on the judicious question¬
ing of nature by critical experiments not necessarily
quantitative;—such, in short, as Newton discusses
in his Optics ; and indeed since Newton himself occu¬
pied the Lucasian chair, there have been perhaps
few philosophers who have shown so remarkable an
aptitude for both kinds of research.
(579.) In 1852 Professor Stokes announced that the re-
the°"efran* franSil:)ility of %ht, which has hitherto been consi-
gibiUtyof ^ere^ lts most inherent and invariable quality, may
light may in some circumstances be altered. The fundamental
be changed, experiment is this:—A beam of solar light is caused
to form a pure and highly dispersed spectrum by Fluores-
passing through two or three prisms in succession,cence-
associated with a lens. The spectrum is made to
fall on a glass vessel containing a solution of sul¬
phate of quinine (a colourless fluid). Whilst the red,
orange, and indeed the greater part of the luminous
spectrum, pass through as if the fluid had been merely
water, from about the middle of the violet “ the
path of the rays is marked within the fluid by a sky-
blue light, which emanates in all directions from the
fluid, as if it (the medium) had been self-luminous.”
This appearance extends far beyond the visible violet,
the presence of the invisible rays (called chemical)
becoming disclosed by the reaction of the quinine;
and the dark bands, both of the visible and the
(usually) invisible spectrum, are marked by obscure
planes traversing the mass of diffuse light. When
the light thus emanating from the interior of the
quinine is examined by a prism, it is found to con¬
sist of rays of various colours and refrangibilities
corresponding to those of the ordinary spectrum ;
from which Mr Stokes concludes that, since only vio¬
let rays and the invisible rays beyond them could have
furnished or excited this emanation, the rays of light
themselves have been transformed into others, with a
lower degree of refrangibility, and possessing the cor¬
responding optical properties. In conformity with
this explanation, Professor Stokes has considered and
accounted for a number of curious phenomena de¬
scribed by Sir David Brewster and by Sir John Her-
schel; called by the former “ internal dispersion,”
by the latter “ epipolic dispersion,” all of which, so
far as they involve anything peculiar, may be reduced
to the general principle that certain bodies by their
action on light have the power of lowering the refran¬
gibility of the rays incident upon them, whether be¬
longing to the visible or invisible spectrum—that is,
of emitting rays of a lower, while under the excite¬
ment of rays of a higher refrangibility. Hence
the phenomenon has been termed the “ degradation”
of light. Mr Stokes has also called it “fluores¬
cence” a word involving no hypothesis, being derived
from the characteristic action of a certain kind of
fluor-spar described by Sir David Brewster.
Many substances, solid and fluid, are found to pos- (580.)
sess these qualities.3 Amongst others, and in the Substa)lces
highest degree, glass coloured yellow by oxide °f
uranium, called in commerce canary glass, and solu- perty.
tions of horse-chestnut bark.
By using sources of light richer than sunlight in (581.)
the highly refrangible rays ; by also using quartz for 1)®mark'.
the prisms instead of glass (which has the power meiu with
of absorbing these to a considerable extent)—Pro- electric
light.
1 1 refer t0 a short but clear paper on the theory and practice of photography by the Rev. W. T. Kingsley, in the Journal
^thePfwtograpJnc Society,, vol. i, August 1853. Mr Kingsley is one of the most scientific and practical improvers of the art.
2Vanshl vcd ^ d°ne ^ a beaUtlM paper on the effect of polarization in modifying the phenomena of diffraction. Camb.
The ter t f th had been detected by Sir D. Brewster, with his usual acuteness and perseverance, in the course of
his researches on “internal dispersion.” The colouring matter of green leaves is one of the most remarkable.
Chap. VI., § 1.]
HEAT.—BLACK.
925
lessor Stokes has obtained a result truly astonishing.
In the case of the light derived from a voltaic arc,
produced by the battery of the Royal Institution
with metallic poles, the visible spectrum formed upon
uranium-glass extended no less than six or eight times
the length of the ordinary spectrum. If, by way of
contrast, a porcelain tablet be used as a screen, the
spectrum terminates at the usual point.1
(581.) [I have already (art. 471) expressed my regret
Mr heat- ^ limits of this Essay prevent me from devot-
sion—the *^nS a section to the physiological part of Optics;
Stereo- but I cannot close the chapter without at least
scope.
naming Mr Wheatstone’s beautiful invention of the
Stereoscope, as by far the most interesting contribu¬
tion recently made to the theory of vision, regarded
in a point of view not strictly anatomical. Although
Mr Wheatstone’s paper was published in the Philo¬
sophical Transactions for 1838, and the Stereoscope
became at that time known to men of science, it by
no means attracted, for a good many years, the at¬
tention which it deserves. It is only since it received
a convenient alteration of form (due, I believe, to Sir
David Brewster), by the substitution of lenses for
mirrors, that it has become the popular instrument
which we now see it, but it is not more suggestive
than it always was of the wonderful adaptations of
the sense of sight.]
CHAPTER VI.
HEAT, INCLUDING SOME TOPICS OF CHEMICAL PHILOSOPHY.
§ 1. Black.—Latent and Specific Heat.—Irvine.—Hutton.—Doctrines of Heat applied to some
Natural Phenomena.
Heatc i Bown to the close of the 18th century, the science
dered in Heat was studied and advanced mainly by che-
the 18th mists, and it was in all respects treated as a branch
century as 0f Chemistry ; a position of which we still find traces
of chemis- introduction of the doctrines of heat (even of
try. radiant heat) into most of our approved treatises on
Chemistry. This circumstance brings us, in this
chapter, into close contact with the most illustrious
chemical names of the second half of the last century
and of the first years of the present. Such were
Black, Cavendish, Lavoisier, and Dalton. Of the last
and two first it may be doubted whether they were not
as prominent discoverers in Physics as in Chemistry.
Davy occupies a similar position. It was not, in¬
deed, until the 19th century had made some pro¬
gress that Chemistry assumed a strongly distinctive
position of its own, and began to attain that large
development and complex character of detail which
render it a science now hardly accessible to those
who do not devote to it their almost undivided at¬
tention. In the days of Black and Cavendish it was
otherwise ; and in the first section of the present
chapter I shall attempt to give an outline of the
characters of the very remarkable men who then
advanced simultaneously the doctrines of Physics
and Chemistry; referring:, of course, chiefly to the
former, but not entirely to the exclusion of the lat¬
ter portion of their researches, particularly with
respect to the atomic and gaseous theories of Dal¬
ton, which have a strongly physical aspect. I have
elsewhere noticed the barrenness of the greater part
of the 18th century in contributions to the experi¬
mental sciences; the temptation is therefore the
greater to dwell a little even on the personal history
of men so celebrated and influential as Black, Caven¬
dish, and Dalton.
Joseph Black was born at or near Bordeaux in (583.)
France, in 1728. His biography, little eventful an<l
almost exclusively academic, has been recorded in as a
some detail by his companions and friends Adam mist.
Ferguson and John Robison (the former of whom
was a relation), in the preface to the posthumous
publication of his Lectures on Chemistry. It is suffi¬
cient for me to state that he entered the University
of Glasgow as a student in 1746. Being destined
for the medical profession, he removed in 1750 or
1751 to Edinburgh, where he benefited especially
by the lectures of Cullen, a most eminent physician,
and the author of a beautiful experiment on the cold
produced during evaporation. Before Black gradu¬
ated (in 1754) he had entered upon a course of chemi¬
cal experiments connected with the causticity of many
earthy bodies, which ended in his first (and perhaps
most famous) discovery of the existence of fixed air or
carbonic acid gas as an essential constituent of marble
and other solids, together with a train of important
consequences. Few inaugural dissertations have been
so interesting to science as that on Magnesia, printed at
Edinburghin 1754, which contained these results. But,
on this purely chemical question we will not enlarge.
1 On Mr Stokes’s experiments, see Phil. Trans., 1852-53; and Proceedings of the Royal Institution.
926 MATHEMATICAL AND PHYSICAL SCIENCE. [Diss. yi.
(584.) The discoveries of Black with which we are chiefly
His disc0- concerned are those of latent and specific heat,
latent and The former, at least, is Black’s sole and exclusive
specific property. When we look back to the state of the
heat. science of heat in the first half of the 18th century,
we are surprised at the exceeding slowness of its pio-
gress. The thermometer had been improved by the
use of the freezing and boiling temperatures of water
for its fixed points, and the adoption of mercury in
its construction by Fahrenheit; the correspondence
of its scale with true increments of heat had been
tested, though imperfectly, by Brooke Taylor ; and
Dr Martine of St Andrews had published an ingen¬
ious work (the best of its period) on the expansion of
different liquids, and on some kindred subjects; but in
general no great step was made until Black, in 1757,
or previously,1 concluded that during the melting of
snow or ice, a great quantity of heat enters into the
body without affecting the thermometer in an appre¬
ciable degree. The heat therefore spends itself or is
absorbed in effecting liquefaction. Black called it
Latent latent (as opposed to sensible) heat. He was led to
heat ab- fliSCOyery by the very simple observation of the
melting11 extreme slowness with which ice is melted by the
ice. application of an amount of heat which would have
raised the temperature of water to an enormous ex¬
tent ; the thermometer plunged in the thawing ice
remaining stationary until it is entirely reduced to
water. When that occurs, heating immediately com¬
mences according to the usual laws. One of Black’s
original experiments clearly illustrates his mode of
procedure. He suspended equal weights of ice at
32°, and of water as near as might be at the same
temperature, in two thin glass vessels 18 inches
apart, in a spacious room having a temperature of
47°. The vessel containing water rose 7° in tem¬
perature in half an hour, but the equal weight of ice
had not wholly melted, nor had its temperature even
slightly increased until 21 half hours had elapsed.
Whence Black concluded (approximately) that as
much heat is requisite merely to thaw ice as would
raise an equal weight of water through 7 x 21 or
Its amount. 147°; a result almost corrrect, although the experi¬
ment in this form is manifestly not unexceptionable.
The converse process of freezing shows how prolonged
must be the application of cold to discharge water at
32° of its latent heat, or heat of liquefaction, and to
convert it into ice.
(585.) Nothing is more admirable in these results than
quences ^ie ^ey throw upon certain natural processes.
Were instant liquefaction the result of the smallest
application of heat to snow at 32°, we should many
times a year be the victims of uncontrollable floods ;
and did water instantly become ice on its tempera¬
ture reaching the freezing point, our lakes and rivers
wotild be rapidly consolidated to the very bottom on
occasion of every frost, and animal life would be im¬
possible.
The analogy of the gradual formation of steam in (585.)
boiling, to the gradual liquefaction of ice, was so Latent
evident as to lead Black to conclude, without anyheat of
1 v vapour.
special experiment, that a great deal of heat becomes
latent during the conversion of liquids into vapour.
It appears to have been in 1762 that he attempted
to determine roughly the amount, by a method simi¬
lar to that just described for the heat of liquefaction.
He compared the time required under the action of a
uniform source of heat to raise the temperature of a
certain quantity of water from 50° to the boiling
point, with that required to boil it away; and in¬
ferring that heat was continually combining with the
water at the same rate, he estimated the latent heat,
or heat of vapour, to be as great as would have raised
the temperature of the water had that been possible
by 810°. This was in October 1762 ;2 about two
years later his pupil, Irvine, made experiments under Exper;_
his direction with a still and refrigeratory, by which ments of
he estimated the heat given out by steam during its Irvine and
reconversion into water. Mr W att prosecuted the ^att-
same inquiry soon after.3 How happily Mr Watt
applied the doctrine of latent heat thus brought ex¬
perimentally under his notice, to the improvement
of the steam-engine, has been already recorded.
One thing strikes us very much on a review of (587<)
these discoveries of Black; it is the great interval Theae laws
which separates the clear perception of a fact from
the explanation of it; or, in other words, from the
clear expression of the more general fact which em- Black,
braces it, although when once given, the explanation
may seem to be almost expressed in the very enun¬
ciation of the fact. Nearly a century before Black,
the lynx-eyed Hooke had noticed that water during
the process of congelation remained unaltered in tem¬
perature, and that the same takes place when it boils,
and this observation had been numberless times veri¬
fied in ascertaining the fixed points of thermometers ;
yet no one before Dr Black had even guessed that
the heat which enters into ice during liquefaction, and
into water during vaporization, remained as it were
a constituent of the water and the steam thus formed,
and could at any time be recovered by a converse
process. Numberless instances occur in the history
of science in which it requires the utmost attention
to appreciate the importance and difficulty of draw¬
ing such seemingly obvious conclusions.
The other great discovery of Black, Specific (588.)
Heat, was in like manner a correct interpretation of Specific
a fact already known. Boerhaave and Fahrenheit ^eat‘
had found that when quicksilver and water were
mixed together, their temperatures being different, the
heat of the mixture was not, as might have been ex¬
pected, the average of that of its ingredients, whether
1 On the authority of a letter from Black to Watt; see Black’s Lectures. 2 Black’s Lectures, i., 158.
3 Ibid., 171-173. In these early experiments the latent heat of steam was a good deal underrated.
Chap. VI., § 1.]
HEAT.—BLACK—IRVINE.
927
the volumes or the weights of those ingredients were
equal. “ Quicksilver, whether it were applied hot
to cold water or cold to hot water, never produced
more effect in heating or cooling an equal measure of
the water than would have been produced by water
equally hot or cold with the quicksilver, and only
two-thirds of its bulk.” Of course, Avhen equal
weights were used, the inequality of effect was still
more striking, for, from the great density of quick¬
silver, it required no less than 30 times the weight of
the -water mixed with it in order that it should con¬
tribute in an equal degree to the production of a
mean temperature. Strange to say, the interpreta¬
tion of this important experiment remained to be
made by Dr Black after half a century. He taught
that temperature is an effect of heat, which is neither
the same in all bodies nor in the same body under
differing circumstances; that the superior effect of
the water to the mercury in determining the tempe¬
rature of the mixture was caused by the fact, that it
is the nature of quicksilver to require a smaller
amount of heat to raise its temperature through
one degree than an equal volume or weight of
water would require under like conditions. Black
made many experiments to satisfy himself of the
constancy of this property in bodies; and with the
assistance of Irvine,1 probably ascertained its nume¬
rical value (the amount of heat necessary to raise an
unit of mass of -water through one degree of tempe¬
rature being the standard) in different cases ; but he
left the subject chiefly in the hands of that observer
and of Watt. The former gave the name of ca¬
pacity for heat to this property, which was after-
wards more happily termed specific heat by Gadolin,
who made many experiments on the subject, as did
also Cavendish and Adair Crawford whose theory
of animal heat, published in 1778, turns entirely on
this property of bodies.
Irvine had the merit, such as it was, of proposing
a theory on which his term capacity for heat was
capacity of principally founded, which occasioned for many years
bodies for after, although now comparatively forgotten, much
discussion. He assumed that the changes in the
temperature of bodies, whether by alteration of
their mechanical condition or by chemical combina¬
tion, were due to a change in the capacity for heat of
the substance or the mixture. He also assumed that
the total amount of heat contained in a body is pro¬
portional to the amount of heat necessary to raise its
temperatui’e through one degree (for example, a
pound of mercury contains altogether one-thirtieth
part of the entire heat contained in a pound of water).
From these principles he deduced the temperature of
absolute zero or privation of heat as follows :—When
sulphuric acid and water are mixed together, the tem¬
perature rises. This rise, according to him, is caused
by the capacity for heat of the mixture being less
(589.)
Irvine’s
theory of
heat.
than the average due to its ingredients. He has, there¬
fore, got the ratio of the whole heat in the bodies
before mixture and after mixture. He has also got
the number of degrees of temperature corresponding
to this difference. Elaving the ratio of these quan¬
tities, and also their difference, the quantities them¬
selves, or the whole amount of heat expires sed in de¬
grees of temperature before and after mixture, become
known, and the temperature of absolute privation of
heat is also known. He applied the same reasoning,
with great ingenuity, to explain the latent heat of li¬
quids and vapours, which he ascribed to their increasing
capacities. He thence deduced other values for the
absolute zero ; but whereas all these determinations
ought to have agreed, at least approximately, they
were found by later experimenters, especially by La¬
voisier and Dalton, to differ so widely—even by se¬
veral thousand degrees—that, since the time of the
latter, this ingenious theory has been nearly aban¬
doned, at least as far as the search after the zero is
concerned; although undoubtedly change in the spe¬
cific heat of bodies is often an important element in
determining their temperature.
To return to Dr Black. From 1756 to 1766 he (590.)
filled the chair of Chemistry and Medicine at Glas- j31atck as a
gow, wrhere he also practised as a physician. In hjs charac-
1766 he left Glasgow for Edinburgh, to succeed Dr ter.
Cullen as Professor of Chemistry—a position which
he held, with great credit to himself and with benefit
to the University, till his death in 1799. His health,
during the greater part of that time, was feeble, owing
to a pulmonary affection, which often interrupted his
lectures, and, it is stated, prevented him from engag¬
ing in severe study without immediate injury. Though
he published one or two papers during these thirty
years, they were of comparatively trifling importance.
His influence on science was chiefly exerted through
the medium of his pupils and of his intercourse with
general society. His lectures are described by those
who had the good fortune to hear them as inimitable
of their kind—grave, dignified, and so interesting as
to rivet the attention. “ Perfect elegance as well as
repose was the phrase by which every hearer and
spectator naturally, and as if by common consent, de¬
scribed the whole delivery.”2 It is probable, also,
that in his private intercourse with his pupils, he in¬
spired them with that love of research which distin¬
guished his own early days, and his taste for neat and
accurate experiment could hardlyfail of being imparted
to a certain extent. Yet we may be permitted to regret
that his constitutional indolence, almost apathy, had
perhaps as great a share as bad health in the inter¬
ruption of his career of discovery. Even when quite
a young man, his most interesting conclusions were
so gradually evolved, that he himself had difficulty
afterwards in fixing their date ; and some of them
were delayed even for years, until he found time to
1 Sir J. Leslie has, I think inadvertently, given the credit of the discovery of specific heat to Dr Irvine.
Lord Brougham.
928
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
make the requisite experiments. So cool a tempera¬
ment was not likely to grow warmer as age advanced.
Almost as indifferent to the honours of discovery as
his stoical contemporary Cavendish, unlike him he
enjoyed in a high degree intercourse with the conge¬
nial society which Edinburgh at that time afforded.
He loved to converse infinitely better than to write;
especially when he could converse intimately with
such men as Adam Smith, David Hume, Adam Fer¬
guson, Principal Robertson, Dr John Robison, John
Home, Clerk of Eldin, and Dr James Hutton.
(591.) Hutton was perhaps Black’s dearest friend, and
Dr Hutton may mentioned here (episodically) as no ordinary
inUmate8 thinker in Natural Philosophy, as well as in Geology
friend— and Metaphysics. Besides the “ theory of the Earth,”
his 'theory which will ever bear his name, and which, after va-
va rourand ri°us transmutations in name and form, is now by
far the most widely prevalent, his theory of Rain
was an ingenious and important speculation. Other
branches of Meteorology also claimed his attention,
particularly, as might have been expected, those
which are connected with the temperature of the
earth. He was one of the first who drew conclu¬
sions from the temperature of springs, with regard to
change of climate due either to increased latitude or
to increased height above the sea. His hygrometer,
in which the dampness of the air was estimated
by the coolness due to evaporation, was unquestion¬
ably the first suggestion of a method now in general
use. His ideas on the constitution of matter were
bold and ingenious, though not on all points tenable.
They resembled those of Boscovich, though inde¬
pendent of them. He published a voluminous trea¬
tise on several subjects in Natural Philosophy, and
a still more formidable one on the Principles of
Knowledge, neither of which attracted much at¬
tention at the time, and have been long forgotten;
yet it is not unlikely that some of his speculations
in metaphysics might be worth the labour of re¬
examination. His friend and commentator, Playfair,
(whose style was as remarkable for perspicuity as Dr
Hutton’s was the contrary) has drawn the following
lively contrast between the characters of Hutton and
Black, which may properly conclude this notice:—
“ Ardour and even enthusiasm in the pursuit of Contrast
science, great rapidity of thought, and much anima-
tion distinguished Dr Hutton on all occasions. ton
Great caution in his reasonings, and a coolness of
head which even approached to indifference, were
characteristic of Dr Black. On attending to their
conversation, and the way in which they treated any
question of science and philosophy, one would say
that Dr Black dreaded nothing so much as error,
and that Dr Hutton dreaded nothing so much as ig¬
norance.; that the one was always afraid of going
beyond the truth, and the other of not reaching it.
The curiosity of the latter was by much the more easily
awakened, and its impulse most powerful and imperi¬
ous. With the former, it was a desire which he could
suspend and lay asleep for a time; with the other, it was
an appetite that might be satisfied for a moment, but
was soon to be quickly renewed Each
had something to give which the other was in want
of. Dr Black derived great amusement from the vi¬
vacity of his friend, the sallies of his wit, the glow
and original turn of his expression; and that calm¬
ness and serenity of mind which, even in a man of
genius, may border on languor and monotony, re¬
ceived a pleasing impulse by sympathy with more
powerful emotions.”1
Black died on the 6th December 1799.2 His death, (592.)
as recorded by his kinsman, Adam Ferguson,3 was Black’s
one of the most touching on record. It succeeded his deati1,
customary state of health by an interval inappre¬
ciably short, and, as appeared by the accompanying
circumstances, without the slightest physical emotion.
The philosophic composure of his whole life was mir¬
rored in the serenity of its close.
§ 2. Cavendish.4—His Singular Character and Attainments—Eminent Chemical Discoveries—
Observations on Heat and on other Branches of Physics—Lavoisier—The Calorimeter—
Theory of Combustion and of Oxidation.
Cuvier has justly remarked, in his biography of which beset the progress of genius cramped by poverty
(593.) Cavendish, that he had to struggle in his scientific and neglect. Cavendish was the descendant of one
aven is . career against obstacles much more rarely encoun- of England’s noblest families, and he was likewise
tered, and perhaps less easily overcome, than those the possessor of enormous wealth ; yet neither of
1 Playfair s Biographical Account of Dr James Hutton, TForfa, vol. iv.
2 Muirhead’s Correspondence of James Watt. Introd., p. xxii. 3 Preface to Black’s Lectures, by Robison, p. Ixxiv.
4 I find an apology almost necessary for introducing at some length the biography of Cavendish into a chapter professedly on
Heat, his positive discoveries connected with which were less notable than in some other departments. But besides that his posi¬
tion in the first rank of chemists naturally indicates his place to be between Black and Dalton, I felt a wdsh to bring out the
relief of the striking intellectual characteristics of those three remarkable men, by placing them in juxtaposition. I may add
that these three sections were the earliest written of this Dissertation, at a time when I had hoped to interweave into its compo¬
sition more of the purely biographical character of each period of scientific history than I found it afterwards practicable in all
instances to carry out. I trust, however, that it may be found a not unwelcome variety amidst the abstruser details of science.
In the case of Cavendish, too, so various are his claims on our notice, that it was inevitable to recur to them in different chap¬
ters, especially in those on Astronomy and Electricity. It was not, therefore, really material under which head the more strictly
personal details were given to which I have alluded.
Chap. VI., § 2.]
HEAT.—CAVENDISH.
929
these powerful temptations could withdraw him even
for an hour from the course of study which he had
marked out; and which constituted for him at once
labour and relaxation, the end of living, and almost
life itself.
(594.) The Honourable Henry Cavendish, son of Lord
His Charles and Lady Anne Cavendish, was born at Nice,
tory. 18 October 10, 1731.1 He entered St Peter’s College,
Cambridge, 24th November 1749, where he resided
during the usual terms for above three years, when
he ought naturally to have graduated, which, how¬
ever, he never did. That he had pursued at least
his mathematical studies with ability and success is,
however, nearly certain from the firm hold which he
ever after retained of them. He joined the Royal
Society of London in 1760, and published his first
paper in their Transactions in 1766. From the time
of his leaving Cambridge for some years his personal
history is not known, though he probably resided in
London.
(595.) The subsequent history of Cavendish is the history
His won- of his studies and his discoveries. The latter were
range of Polished in concise memoirs, written with scrupulous
scientific precision, and all printed in the Philosophical Trans-
knowledge. actions. If collected (which they have not been) they
would fill but an insignificant volume, yet include all
the requisites to establish a first-rate reputation. His
studies no doubt were enormous, for they occupied
every disposable moment of a life prolonged almost
to fourscore. They may be guessed at (in addition
to the published results) from his manuscript remains,
a few of which have been edited recently, but the
larger part remains in manuscript in the possession of
his heirs. Few if any branches of exact science were
unfamiliar to him ; and his published papers include
astronomy, mechanics, electricity, heat, chemistry,
and meteorology, besides which he cultivated mathe¬
matics and geology. His reputation is one of those
which may be called in a peculiar sense European or
universal, because it marked a great epoch in science
to which the publication of his writings materially
contributed. That epoch was when chemistry be¬
came a science of weight and measure. Cavendish
was a weigher and measurer almost by nature, and
entirely so by habit. It appears from his note-books
that he took the most scrupulous pains to ascertain
and record the quantities of the ingredients employed
in every experiment, even though they might be im¬
material to the result; and his whole life was metho-
.dical in the same proportion. The immense impor¬
tance of Cavendish’s labours to the progress of science
in his day is found in the unanimous testimony of
his contemporaries ; and notwithstanding the extreme
retirement in which he lived, and the rarity of his
appearances as an author, he was generally regarded
as perhaps the leading man of science in England of
his day; and his good opinion was considered by con¬
temporary philosophers as their highest praise. Sir
Humphry Davy’s opinion of him (recovered and
published by Dr Davy from a manuscript lecture)
represents that of such of his countrymen as were
qualified to form one, and the writer of it was
usually fastidious in his judgments of others:—“It
may be said of Mr Cavendish, what can perhaps hardly
be said of any other person, that whatever he has
done has been perfect at the moment of its produc¬
tion. His processes were all of a finished nature.
Executed by the hand of a master, they required no
correction ; and though many of them 'were per¬
formed in the very infancy of chemical philosophy,
yet their accuracy and their beauty have remained
amidst the progress of discovery, and their merits have
been illustrated by discussion, and exalted by time.”
After this eulogium of so competent a judge, I (596.)
shall be satisfied by a simple enumeration of those Chemical
chemical discoveries which were the most splendiddlscovenes
results of his career, but which hardly come within dish?'eU"
the immediate scope of this dissertation. To him we
are mainly or entirely indebted for the knowledge of
hydrogen as a distinct elastic fluid or gas ; of the
exact constitution of the atmosphere, and the won¬
derful constancy of its ingredients; of the composi¬
tion of nitric acid; and finally, according to the
opinion of most persons (at least till lately), of
the non-elementary nature of water, and of its
precise constituents. This last and crowning dis¬
covery has indeed been contested, and made the sub¬
ject of a prolonged and bitter scientific controversy,
which hardly could be said to exist until the con¬
temporary generation who witnessed the facts, and
also the succeeding one, had passed away. For Caven¬
dish received until his death, and for nearly thirty
years after, the unquestioned tribute of at least the
primary merit in so great a step in science. The
topics more peculiar to the present essay (sufficiently
extensive besides) enable us to dispense with the un¬
welcome task of once more analyzing a controversv
purely personal, and which has almost filled volumes.
I shall content myself with stating two considera¬
tions, which must have great weight in turning the
balance of the evidence (supposing it balanced) in
Cavendish’s favour. The first is founded on the
behaviour of Watt himself; the second on the known
character of Cavendish.
As to the former consideration, I would remark that /597 ^
Watt withdrew the letter to Priestley which he had Contro-
submitted to the Royal Society and which contained vfrsy on
his views respecting the composition of water, before dj.sc°vei7
it had been read at the meetings of that body.2 The position of
causes of this suppression are candidly stated by water.
Watt in a letter to Sir Joseph Banks, published by
Mr Muirhead,3 in which he states that he “ thought
1 Life of Cavendish, by Dr George Wilson ; a valuable biography, which has been printed in the series of publications of the
“ Cavendish Society,” and thus unfortunately has had but a limited circulation.
2 Correspondence on the Composition of Water, p. 30. 3 JUd p, 52.
VOL. I. 6 b
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
Argument
from
VV att’s be¬
haviour.
930
it prudent to delay the publication until he should
have considered it [the theory of the composition
of water] more maturely, and have made some ex¬
periments to determine the proof or falsehood of it.
This, it must be owned, was not the language of a man
who had acquired that amount of conviction which
is needful,—not to broach a theory,—but to hold fast
by it against all opposition. With the caution which
formed part of his character, Watt was unwilling
to hazard his reputation by adhering to a doctrine
which appears at the time to have received no sup¬
port from his scientific friends, especially Dr Black.
Having read the correspondence published by Mr
Muirhead, I cannot doubt that Watt, whatever his
private opinions might continue to be, would never
have urged his views on an unwilling public, but
would have finally suppressed the letter to Priestley,
had not the experiments and claims of Cavendish at
home, and of Lavoisier in France, reanimated all
his zeal for the assertion of his opinion. This in¬
deed Watt ingenuously admits in the letter to Sir
Joseph Banks just cited, where he states that the
fact of similar theories having since been supported
by philosophers of first-rate abilities, removed his
second objection to publication. As the suppression
of his paper would have relieved Watt of all the re¬
sponsibility of error, it seems impossible to allow him
the advantage—of which that suppression deprived
him—of anticipating the date of his matured convict
tion; and to this conviction we have his own evidence
that Cavendish’s publication as well as certain addi¬
tional experiments of his own influentially contri¬
buted. Watt, in after life, may be said to have tacitly
relinquished to Cavendish the honour which, in the
first irritation of the conflict of their claims, he showed
nodisposition to do; it is, therefore, reasonable to infer
that, on reflection, he saw good reasons for doing so.
By this I mean that he suffered judgment to be passed
in favour of Cavendish’s claim in the writings of many
of his eminent contemporaries, without attempting
publicly to correct the all but universal impression
which they made. In one instance, he almost ho¬
mologated this adverse judgment:—In the article on
Steam, written by Bobison, and revised by Watt in his
last years and after Cavendish’s death, this passage
appears,—“ This is fully evinced by the great disco¬
very of Mr Cavendish of the composition of water1
from which it must be concluded, first, that Bobison,
the intimate friend of Watt, and the almost chival¬
rous defender of his fame, believed Cavendish to
be the true discoverer ;2 secondly, that Watt, in
commenting on this article in 1814, permitted the
fact to be thus transmitted to posterity. For, in
his numerous animadversions on other parts of the
same papers, he gives (as I have pointed out in the
note to art. 318) free expression to the sensitive¬
ness which he felt lest Dr Black should derive any
credit to which he was not entitled in connection with
the steam-engine, but he suffers the passage just
quoted to pass without remark, Such being the
case, and waiving all purely chemical discussion,
I am of opinion that Watt’s friends should have
left the matter as he was content to leave it.
With reference to the argument from Cavendish’s (598.)
character, I would remark that whilst the claim of Argument
Watt cannot be maintained without impeaching the
honour and integrity of his rival, and showing that he 0f caven-
stooped to subterfuge in order to appropriate to him- dish,
self a discovery due to another—it would yet be diffi¬
cult to find in the whole range of scientific history
(without excepting the venerable name of Newton), an
individual so devoted to knowledge for its own sake,
so indifferent to the rewards of discovery, so averse to
the publication of what he felt to be important, and
knew to be original, so insensible to the voice of
praise when applied to himself, so ardent in acquaint¬
ing himself with the labours of others, and so liberal
in assisting them. Such a man was Cavendish; and
that he should stoop even to the common artifices of
little minds for exalting his own reputation at the ex¬
pense of others, would itself be incredible ; how much
more the insinuation (grounded solely on alleged cir¬
cumstantial evidence) that in doing so he disregarded
the plainest dictates of honour and justice.
Black and Cavendish were nearly contemporaries, (599.)
the former having been born only three years earlier.
But I doubt whether these two men, so congenial in periments
their studies, so different in almost every circum- on latent
stance, whether of fortune or temperament, ever met. ^atspecific
They had this, however, in common, that they pub¬
lished their discoveries and observations with reluc¬
tance, and were fastidious in the manner of doing so.
Black’s experiments, both in chemistry and on heat,
preceded those of Cavendish, and with regard to the
latter subject (heat) it is probable that Cavendish
pursued investigations and made original experi¬
ments, in which he had been unknowingly anticipated
by the Scotch professor. His researches on latent
and specific heat (though he did not employ these
terms) appear to have been subsequent to Black’s,
but to have preceded those of Crawford and Wilcke ;
and it is not impossible that his was the earliest, or
one of the earliest, determinations of the amount of
heat absorbed in the conversion of water into steam,
for which he obtained various results between 923°
and 982°, a mean of which would be very near the
1 Robison’s Mechanical Philosophy, ii., 21.
2 The article Watek in the early editions of the Encyclopaedia Britannica has been quoted as the production of Robison,
of which there does not appear to exist any proof, whilst the probability, as shown in the text, lies all the other way. I learn
upon the best authority that the proprietors of this Encyclopaedia have no clue to the authorship of that article, and that it is
not included in the lists of Robison’s known contributions. The part relating to the present question was expunged in the Fourth
Edition, and a reference made to the article Chemistry where Cavendish received the credit of the discovery.
%
Chap. VI., § 2.]
HEAT.—CAVENDISH.
931
(600.)
Papers on
the earth’s
attraction,
and theory
of electri¬
city.
(601.)
Singular
personal
character¬
istics of Ca¬
vendish.
truth. But it is needless to dwell upon these obser¬
vations, however original, because they were volun¬
tarily suppressed by the author, and have only re¬
cently been brought to light from his manuscripts.1
What he did publish in connection with this subject
was a paper on the construction and graduation of
meteorological instruments, especially thermometers,
and others on the temperature at which mercury
freezes, and on freezing mixtures. The former of
these papers was, as might be expected, far in ad¬
vance of its age in the degree of exactness which was
showm to be attainable in the construction of ther¬
mometers, and scarcely even now can it be considered
as obsolete. The papers on freezing mercury finally
corrected the exaggerated notion at first entertained
of the extreme cold at which that metal becomes
solid, and also contain valuable views on the sub¬
ject of congelation, and fixed the latent heat of water
at 150°. He calls this, “generation of heat” during
liquefaction, objecting to Blades term as relating
“ to an hypothesis, depending on the supposition that
the heat of bodies is owing to their containing more
or less of a substance, called the matter of heat; and
as I think Sir Isaac Newton’s opinion that heat con¬
sists in the internal motion of the particles of bodies
much the most probable, I chose to use the expres¬
sion, heat is generated.”2
Two of Cavendish’s most important researches re¬
fer to the attraction and density of the earth, and to the
mathematical theory of electricity. The former (which,
in principle, was derived from the Bev. John Michel!)
has been already analyzed in the chapter on Astro¬
nomy (art. 156). The latter will be more conve¬
niently referred to in our chapter on Electricity.
Cavendish’s publications extended over the greater
part of his active life, but those on chemistry and
electricity, on which his fame principally depends,
do not extend beyond the year 1775 ; the date of his
paper on the density of the earth is 1798. He died
24th February 1810, at the age of 79. He appears
to have.exercised scarcely less influence by his general
devotion to science, than by his specific discoveries,
great and original as they were. In 1782, when
Playfair met him incidentally in London, he de¬
scribed him as being generally looked up to as one
possessed of talents confessedly superior, and as the
only member of the Boyal Society who then united
the knowledge of mathematics, chemistry, and ex¬
perimental philosophy. The absolute devotion of
his life to inquiries the most abstractly scientific,
whilst he showed an entire indifference to the luxuries
which his wealth might have commanded, and the
social station to which his birth entitled him, could
not fail to inspire respect for his character, as well
as to obtain the homage of mankind for pursuits
so dignified and so generally disregarded. Many
curious anecdotes are related of the annoyance which
the inevitable accumulation of his unspent income
occasioned. He no doubt would have distributed more
liberally what he so little valued, but for the amount
of time and inquiry which such a course must have
compelled him to withdraw from his beloved pursuits.
Some instances of his generosity are on record, and
others, no doubt, will never come to light. M. Biot’s
epigrammatic description of him will probably long
remain applicable,—“ II etait le plus riche de tous
les savans, et probablement aussi le plus savant de
tous les riches.”
This isolation of interest was doubtless due, quite (602.)
as much to a constitutionally morbid temperament,
as to a real misanthropy. He avoided even the most
casual intercourse with his fellow men, excepting only
when it was likely to bear the immediate fruit of
scientific information. He almost never visited his
relatives, and his heir paid him a visit of a few minutes
once a year ; but he frequented regularly the social
meetings of the Boyal Society Club, and the evening
reunions of Sir Joseph Banks. But he came, not to
participate, but to increase his stores ; if he spoke, it
seemed to be by inadvertence, and he was silenced
by a question, or even by a look. “ A sense of iso¬
lation from his brethren made him shrink from their
society, and avoid their presence; but he did so as
one conscious of an infirmity, not boasting of an ex¬
cellence. He was like a deaf-mute sitting apart from
a ciixde, whose looks and gestures show that they are
uttering and listening to music and eloquence in pro¬
ducing or welcoming which he can be no sharer. . . .
He was one of the unthanked benefactors of his race
who was patiently teaching and serving mankind,
whilst they were shrinking from his coldness, or
mocking his peculiarities. . . . Such was he in life,
a wonderful piece of intellectual clock-work, and as he
lived by rule he died by it, predicting his death as if it
had been the eclipse of some great luminary, . . . and
counting the very moment when the shadow of the
unseen world should enshroud him in its darkness.”3
I shall only add, that Cavendish was elected one ^
of the eight Associates of the French Institute in
1803. This is a distinction perhaps the highest, of
a formal kind, to which a scientific man can aspire,
and was given at a time when, as an Englishman, he
must have felt it to be peculiarly honourable.
The philosophical character of Cavendish resembled
in many respects that of Newton; and with but a slight Hisphiio-
modification of its secondary ingredients, he might sophical
have been, perhaps, another Newton in experimental character,
physics. His singular incommunicativeness, and the
absence of a laudable ambition to perpetuate his name
by the establishment of great theories, are perhaps
the main reasons why his reputation, except in che¬
mistry, did not stand yet higher than we find it.
1 By the Rev. W. Vernon Harcourt in British Association Report for 1839. Compare Wilson’s Life of Cavendish, p. 446.
2 Phil. Trans. 1783.
3 Wilson’s Life of Cavendish.
932
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
A man indifferent to external relations pursues even
his studies at a disadvantage; and the patient la¬
bours of so long a life devoted to a single object,
would perhaps have told to greater effect had ho
published the results more frequently, and had he
communicated more freely with those qualified to in¬
terchange their views with his. His excellent mathe¬
matical education, and his unusual skill in experi¬
ment, combined with a habit independent of either,
but not less valuable, of patiently drawing inferences,
might have placed him in the first rank as a discoverer
in Heat, in Electricity, or in Optics,1 each of which
sciences was so soon to take a surprising step in ad¬
vance. In several of his important researches, he
was more or less anticipated; a circumstance which
his cold nature would perhaps scarcely have allowed
him to make an effort tp prevent. Black preceded
him in most of his excellent experiments on heat;
iEpinus in his theory of Electricity ; Watt was at least
close on his traces in suspecting that water consists
of oxygen and hydrogen; and the admirable experi¬
ment on gravitation had been devised by his friend
Michell, and was not improbably recalled to his re¬
collection, by the happy use of the torsion balance
by Coulomb. It is given but to a few to achieve great
discoveries, nor is the longest life always the most
productive. Cavendish had his share, and some of
the most considerable of these were even made later
in life than is usual amongst experimentalists.2 It
is no mean eulogy of him to say, that the purity and
ardour of his pursuit of truth were never exceeded,
and that had he been more ambitious of praise, he
might have stood as pre-eminent in mathematical
physics as he did in chemistry.
(605.) Antoine Laurent Lavoisier stands in intimate
Lavoisier, connection with Cavendish, as well by the nature of
his pursuits generally, as by the brilliancy and im¬
portance of his chemical discoveries, which were
nearly contemporaneous with those of Cavendish.
He was born in 1745, and suffered by the guillotine
on the 8th May 1794, without even the shadow of
a misdemeanour. He was attached to the sciences
of Heat and Chemistry, which he prosecuted with
admirable success. He happily availed himself of
the discoveries of Black, Priestley, and Cavendish, as
well as his own, to establish the important chemical
theory which has immortalized him. It is to be re¬
gretted that he was not always just in citing the
English writers from whom he so freely borrowed.
Such looseness was, however, common at that period,
and (unfortunately) has continued to be so in France
even to our own time.
(606.) Lavoisier’s more important papers may be classed
His contn- under two heads ; those referring more immediately
heatTnd0 to t^ie subject of Heat as a branch of physics ; and
chemistry, those of a more strictly chemical character, princi¬
pally in support of the “ Oxygen-Theory,:
sequently also intimately connected with the doctrine
of heat considered in reference to its most ordinary
source, Combustion.
He published in 1772 a paper on the Latent Heat (607.)
of Water, and some years afterwards one on the Latent Papers on
Heat of Steam, which, in general, merely reproduce h.eal~cal°'
the views of Black. In the memoirs of the Aca- specific
demy of Sciences for 1780 (published 1784), we heat,
find an important paper on Heat written in conjunc¬
tion with Laplace, in which the calorimeter is de¬
scribed, though not under that appellation, together
with its applications and their results. The prin¬
ciple of the calorimeter is too well known to require
to be detailed here; but the authors of the joint
memoir refer, with commendable precision, to the pre¬
vious labours of Wilcke of Sweden, who first employed
the melting of snow to measure the quantities of heat
given off by bodies in cooling. To Laplace and La¬
voisier, is, however, due an important addition which
could alone impart any value to the results,—that of
the external chamber of ice which prevents fusion
taking place by the contact of the external air and
by radiation. The French philosophers were not so
successful in eliminating the other source of inac¬
curacy specified by Wilcke, which arises from the
difficulty of drawing off the whole of the melted
water. Sir John Herschel has of late years proposed
what seems to be an important improvement on the
calorimeter, by filling the interstices of the snow or
ice with water, and estimating the quantity of the
former melted by the contraction of volume'of the
compound mass. I am not aware that it has been
as yet practised. I have stated in Art. (88) one ground
on which the idea of the calorimeter (so far as not
anticipated by Wilcke), may be probably ascribed to
Laplace. Another is to be found in the fact that,
in the opening of the description of the method in
the paper which we are considering, Laplace writes
of himself in the first person.
Of the memorable revolution which Lavoisier in- (608.)
troduced into chemistry, more immediately in con- Chemical
nection with the subject of combustion, I cannot b^ombina-
expected to speak here at length. It is well known tion and
that the early chemists entertained more correct oxidation,
views as to the calcination of metals than those pre¬
valent during the greater part of the eighteenth cen¬
tury under the influence of Stahl’s theory of Phlo¬
giston ; and that Lavoisier, in the first instance, only
led chemists back into the right road by insisting
that the increase of weight observed when metals are
calcined in air, must be due to some ponderable sub¬
stance associated with the metal and derived from the
air, and not to the escape of an imaginary spirituous
substance, endued with positive levity, and termed
Phlogiston. But it required the progress which had
already been made in pneumatic chemistry by Black
and Priestley, and especially the discovery of oxygen
and con'
1 This last subject seems to have been comparatively indifferent to him.
2 His discovery of the composition of water was made when he was about fifty years of age.
Chap. VI., § 3 ]
HEAT.—LAVOISIER—DALTON.
933
(610.)
Dalton—
his early
circum¬
stances ;
contrasted
with those
of Caven¬
dish and
Black.
by the latter (a fact sparingly alluded to by Lavoi¬
sier), to give to the true theory a stable foundation.
That metals calcine, and that flames burn by the aid
of the vivifying principle of the atmosphere abstracted
from it, and which adds its weight to the compounds
produced, was the primary step made by Lavoisier;
to which, by cautious, yet rapid inductions, he added
the knowledge of oxygen as the usual (he believed
the sole) acidifying principle, and demonstrated the
true nature of carbonic acid. To these various phe¬
nomena thus happily reconciled, he added the theory
of respiration, confirming it by the effects observed
in air which has undergone that process. These, and
many other consequences of the f‘ oxygen theory,”
were developed in a numerous series of admirable
memoirs. The reception of it was anything but in¬
stantaneous ; and the hesitation and delay which oc¬
curred, enable us, as Dr Whewell has well remarked,
to estimate the force of mind which was required to
promulgate the theory,—as the subsequent course of
discovery, and its infinite applications in practice, best
attest its importance.
Lavoisier was still occupied in extending the (609.)
conclusions of his chemical doctrines, when he was
overtaken by the unprovoked sentence to a violent death,
death. Like Archimedes, he begged a short respite
for the completion of experiments in which he was
immediately engaged, but he was silenced by the brutal
reply that “ the Republic had no need of philoso¬
phers.” He left a name equal to any in the science
of his time, and adorned by the memory of public
and private virtues.
§ 3. Dalton.— Theory of Gases and Vapours.—Law of Expansion by Heat.—Atomic Theory of
Chemistry.—Guy-Lussac.
John Dalton, the chief author of the theory of che¬
mical equivalents or the Atomic Theory (as he preferred
to call it), and of many important researches on the
constitution of elastic fluids, was born at Eaglesfield,
near Cockermouth in Cumberland, on the 5th of
September 1766.1 His parentage was humble, and
his family belonged to the sect of Quakers, whose
tenets he, to the close of his life, professed. Had
we wished to invent a striking antithesis in the per¬
sonal histories of the cultivators of science, or to
illustrate merely the various soils on which rich
crops of discovery may be reared, we could scarcely
have imagined more striking contrasts than in the
social positions and advantages of Black, Cavendish,
and Dalton—three of the names which we have selected
in illustration of the history of physics of their age.
Cavendish we have seen connected with one of the
noblest families in England, and wealthy almost be¬
yond the dreams of the covetous ; spending his life
in or near London, and enjoying every facility of di¬
rect communication with the first scientific celebrities
at home and abroad;—Black, almost the beau ideal
of an Academic, not wealthy indeed, but surrounded
by all the opportunities of study, of information, and
of social intercourse which he desired; passionless
almost to a fault; admired by his pupils and friends;
enjoying, in short, all the advantages -which educa¬
tion and a literary position can afford for the prose¬
cution of a favourite study;—Dalton, on the other
hand, poor and hardly winning a well-earned sub¬
sistence by private tuition, from the time he was
himself a child until near the close of his long ca¬
reer,—with few friends, a scanty education, and a
scantier library,—attaining, through his unaided and
long almost unheeded efforts, and by means of an
apparatus constructed entirely by himself, a position
in the world of science unquestionably not second to
that of either of his more highly-favoured contem¬
poraries.
At the age of thirteen he had commenced the ardu- (611.)
ous office of an instructor; and from 1781 to 1792
pursued the same occupation in a humble sphere
at Kendal, where he fortunately became acquainted
with Mr Gough, a blind gentleman of some fortune,
who devoted his time to the prosecution of science
in nearly all its branches, and particularly of mathe¬
matical subjects, of which he has left an enduring
record in many ingenious papers, published chiefly
in the Manchester Transactions and in Nicholson's
Journal. He patronized young Dalton, giving him
free access to his library and apparatus, and receiv¬
ing from him in return the benefit of his assistance in
prosecuting his experiments. Dalton always recog¬
nised (as he had unquestionably good reason to do)
the merits of his patron, and the importance of the
advantages which he had derived from his advice
and example. Indeed, without some such fortunate
concurrence of circumstances (and something simi¬
lar may be noted in the history of nearly all self-
educated men), it could hardly have been hoped that
Dalton would have been so well grounded in the ma¬
thematical principles of at least some branches of
Natural Philosophy as he probably was. For, though
his discoveries bear mainly on the science of chemis¬
try in the wide sense in which it was then under¬
stood, yet geometrical precision is after all their fun¬
damental characteristic ; and whether in treating of
the constitution of a gas, or of the scale of a thermo¬
meter, or of the composition of a salt, it is evident that
numbers and ratios were the ideas predominating in
1 Life of Dalton, by Dr Henry, in the publications of the Cavendish Society. The present section was originally written
before the appearance of this biography.
934
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI*
his mind. In this he resembled Cavendish; but he
did not resemble him, and in one sense may be said
to have surpassed him, in the boldness, we might call
it audacity, with which on a frequently too slender
foundation of facts Dalton established, to his own
satisfaction, by reasoning almost as much d. priori as
that of the mathematician, comprehensive physical
theorems expressing the laws of phenomena.
(612.) The more important of these refer to the consti-
Dalton’s tution of gases and vapours, together with their rela-
writings. ^ions to heat, and to the combinations of bodies by
chemical affinity. We shall endeavour to give some
account of these researches separately. They are to
be found detailed in the Memoirs of the Literary and
Philosophical Society of Manchester (particularly the
fifth volume), and in Dalton’s Nevj System of Che¬
mical Philosophy, of which three successive parts ap¬
peared in 1808, 1810, and 1827, of which the first
is the most original and important.
(613.) I. We shall first speak of his researches connected
Researches with gases and vapours. It had been noticed by
and’va-3 Priestley and others that when gases exercising ap-
pours. parently no chemical action upon one another, are
mixed in a confined space, they become, after the
lapse of a longer or shorter time, completely inter¬
mingled, and that without any regard to even great
differences in their density, the particles of the lighter
gas diffusing themselves contrary to gravity through
those of the denser, and causing them in their turn to
ascend. The uniform composition of our atmo¬
sphere, in all circumstances and at all heights, is a
striking example of this property. In explanation of
it, Dalton had in 1801 arrived at the conclusion,
“ that the particles of one gas are not elastic or re¬
pulsive in regard to the particles of another gas, but
only to the particles of their own kind.” The fun¬
damental experiment on which this singular con¬
clusion was based was the following:—That the
quantity of vapour of water (which, when purely
elastic, may be considered as a gas) which can exist
uncondensed in a given space, depends solely upon
the temperature, and is independent of the presence of
air and of its own density. Thus water, or any other
evaporable liquid, being introduced into a space con¬
taining air, or any . other gas, of any density, but
subject to a constant external pressure, the space in
question becomes damp by the evaporation of the
liquid ; now the amount of the latter converted into
vapour depends, according to Dalton, upon the single
circumstance that the vapour yielded by it must
have the precise elasticity due to its temperature.
Its elastic force being added to that of the dry air,
the whole will expand until equilibrium is restored
with the constant pressure without, and this will oc¬
cur as soon as the elasticity of the dry air alone
(proper to its increased volume), addhd to the elasticity
of the vapour alone (depending solely on its tempera¬
ture), are together equal to the pressure which they
have to support. In short, to use the precise enun¬
ciation of Dalton himself, “ in all cases the vapour
rises to a certain force, according to temperature,
and the air adjusts the equilibrium by expanding or
contracting as may be required.”1 *
The importance of this law (easily verified in the (614.)
particular case) is readily perceived. Not only did Theory of
it affect the results of almost every experiment in bygronie-
pneumatic chemistry, but it rendered a new theory oft1^’
hygrometry indispensable. The older theory of Hal¬
ley, Leroy, and Franklin was, that the direct affinity
between air and water drew up a portion of the lat¬
ter into the former with the aid of heat, whilst De
Saussure (Essai sur VHygrom^trie, 1783) believed
that the conversion of water into vapour took place
first and independently by the action of heat, and that
it was then drawn up into the atmosphere by the at¬
traction of the gases which compose it. Dalton’s
experiments show that the air and the vapour mix
without the slightest mutual interference or reac¬
tion. He founded thereupon an excellent prac¬
tical method of determining the amount of vapour
in the atmosphere. He first formed a table of the
elasticities of watery vapour or steam for all tem¬
peratures between 32° and 212°; and so simple and
accurate were his methods, at least for the lower de¬
grees of the thermometer, that his numbers are still
received as amongst the best we have. He operated
merely with a carefully constructed barometer, into
the vacuum of which he introduced a few drops of
water, and raising the temperature by means of a
tube embracing it, and which could be filled with
water at pleasure, he observed carefully the depres¬
sion of the mercurial column. The elasticities thus
determined commenced with 0‘2 inches of mercury at
32° up to 30 inches at 212°. These numbers, con¬
sequently, represent the utmost elasticities of vapour
which can exist either in air or without air at the cor¬
responding tempei’ature. If we attempt to add more
vapour, or to lower the temperature, in either case
moisture will be deposited. Hence to find the quan- Dew-point
tityof vapour in the atmosphere when not absolutely
damp, it is sufficient to ascertain the temperature at
which it becomes so. This Dalton did by filling a
1 The exact expression of the effect is this, v———, where p represents the pressure expressed in inches of mercury upon a
. “P
given volume (equal to unity) of dry air; f the force of the vapour in vacuo at the temperature of experiment, also in inches of
mercury ; and v the volume which the mixture of air and vapour occupies under the given pressure p after saturation. It is evident
thatp —/ being the pressure due to the elasticity of the dry air apart from the vapour, when we affirm that the volume (1) becomes
——y, we in effect affirm that Mariotte’s (or Boyle’s) law connecting volume and pressure holds true for air which is mixed with
vapour, just as though vapour were absent or its space void.
Chap. VI., § 3.]
HEAT (ATOMIC CHEMISTRY).—DALTON.
935
thin glass with cold spring water, or by adding, if
necessary, the solid nitrate of ammonia, until the
temperature fell so far that dew began to be deposited
on the surface. This excellent method constitutes
in fact the dew-point hygrometer. It has received
various forms from Mr Daniell and others, but the
original one is probably the best.
(615.) These important laws and deductions being fully
mixed°f understood, the theory of the mixed dry gases follows
gases. as a simple corollary. For it merely asserts of them
what has been admitted in the case of steam, that
they may diffuse themselves, and exert their elastic
forces quite independently of one another; so that, for
example, in our atmosphere the total pressure is made
up of the partial elasticities of the oxygen, nitrogen,
and carbonic acid which compose it, each acting to
the same amount as if it alone had existed in the
space which it occupies. In his essay of 1801, Dal¬
ton stated his view of these facts thus :—“ The par¬
ticles of one elastic fluid may possess no repulsion or
attractive power, or be perfectly inelastic with regard
to the particles of another.”
(616.) Discoveries so practical could not fail to excite
Daitoirs immediate attention, especially at a time when the
ideason*5**1 researc*ies chemists were earnestly directed towards
the subject. ^,e gases- “ The facts and experiments,” Dalton
tells us in his Chemical Philosophy, “were highlv
valued ; some of the latter were repeated and found
correct, and none of the results controverted; but
the theory was almost universally misunderstood.”
Its opponents were Berthollet, Thomson, Henry, and
others, and the replies of the author are contained in
the work just cited. But he appears to have felt the
force of the objection, “ Can it be conceived that an
elastic substance exists which adds its volume to that
of another, and which, nevertheless, does not act on
it by its expansive force V—for in his chemical phi¬
losophy he abandons the comparison of gaseous par¬
ticles to similar magnetic poles which repel each
other, but are inert towards non-magnetic matter, and
allowing that heat is the primary cause of repulsion
in all gases, ascribes their diffusion contrary to gravity
to the dissimilar size of their spherical molecules.
“ The particles of one kind being from their size un¬
able to apply properly to the other, no equilibrium
can ever take place amongst the heterogeneous mole¬
cules. The intestine motion,” he adds, “ must there¬
fore continue till the particles arrive at the opposite
surface of the vessel against any point of which they
can rest with stability, and the equlibrium at length
is acquired, when each gas is uniformly diffused
through the other.” It may be seriously doubted
whether this theory of the facts will bear examina¬
tion, at least no attempt has been made to demon¬
strate it on mechanical principles. The subject has
been allowed to remain during more than forty years of
unequalled activity in such speculations without ma¬
terial light being thrown upon the proximate causes
of these wonderfully general and simple truths. Yet
it can hardly be doubted that the mechanical theory
of the gases and vapours is capable of a great exten¬
sion, and even of being illustrated by simple experi¬
ments. But the attention of chemists has been with¬
drawn from the physical bearings of their science by
the prodigious increase in the number of compounds
which they have had to analyze and classify. The
most important sequel to Dalton’s discoveries has
probably been that of Professor Graham, whose ex- Mr Gra-
periments prove that gases when separated by a ham’s Jaw-
porous partition permeate it in both directions, until °.f dlffu"
they have mixed in proportions which are inversely
as the square root of their density. This law clearly
shows the purely mechanical causes by which the
diffusion is effected.
A discovery of Dalton, which has scarcely been (617.)
considered second in importance to those we haveDalton on
mentioned, is that the rate of expansion of all gases gioi^of the
by heat is the same. Thus thermometers of air, hydro- gases by
gen, and carbonic acid would all markthesame degree heat-
when plunged in the same medium ; whilst the mer¬
curial thermometer shows a more rapid expansion, at
higher temperatures, if the air thermometer be taken
as the standard. This important fact was soon
after but independently announced by Gay-Lussac of
Paris. Dalton’s publication dates from 1801. In
his Chemical Philosophy, he gives his view of the
difficult subject of a true thermometric scale; which
he does not suppose to be correctly represented by
the simple expansion of any known substance; but
that the gases expand with true increments of heat
in a very slow geometrical progression, whilst li¬
quids expand as the squares of the true temperatures
from their freezing points. These and other laws
equally arbitrary have not received support from
later and more precise experiments; and in the se¬
cond volume of his work (1827) he freely acknow¬
ledges the correction of his hypothesis by the more
recent French experiments.
II. I now proceed to the other part of Dalton’s (618.)
labours on which his reputation is principally based; ^tomb;8
namely, the clear assertion and experimental esta- Theory,
blishment of the Atomic Theory or doctrine of chemi¬
cal equivalents. I introduce it here on account of
its important bearing on all physical questions in
which the constitution of matter and the forces act¬
ing at minute distances are involved.
Early opinions on the constitution of matter and (619.)
chemical combination.—Two opinions have prevailed Gariy opi-
from the very earliest times respecting the constitu-
tion of body :—that which supposes its entire homo- tution^f1
geneousness, and that which allows that it consists matter,
of material parts or atoms separated by void spaces;
these parts or atoms being indivisible. This last is
the doctrine of Democritus and Epicurus, and in
modern times of Bacon, Newton, and Dalton.1 The
former opinion has been held by Leibnitz, and many
1 The reader will find ample details on the opinions of the older philosophers in Daubeny’s Introduction to the Atomic Theory,
936
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
writers of the recent German school. Abstracting
as far as possible from the more purely metaphysical
difficulties (such as those which the consideration of
Leibnitz’s law of continuity introduces), we may
perhaps be justified in stating that, whilst the objec¬
tions urged against the existence of atoms fall upon
our inability to conceive and describe the properties
of these individual ultimate parts in a consistent
manner,—the objections to the other notion meet us
at an earlier stage, and seem to defy any clear con¬
ception of the nature or possible existence of com¬
pound bodies, or of bodies in two states of consis¬
tence. Admitting atoms—whilst acknowledging our
inability to describe them individually—we can clearly
enough conceive the phenomena of condensation, ra¬
refaction, evaporation, &c., and also of the combina¬
tion of elements in compounds possessing distinct
properties; but excluding them, or allowing that
matter is penetrable by matter throughout, is it pos¬
sible to conceive clearly of such a compound,—as for
example, of the perfect diffusion of two gases in the
same space, yet each gas retaining its individuality
so completely as to admit of easy and complete se-
Boscovich. paration from the other "? The theory of Boscovich,
which has been sufficiently touched upon by Sir John
Leslie in the previous Dissertation, was intended, no
doubt, to reconcile the two opposing theories, and it
cannot be doubted that it is in many respects an in¬
genious solution. Yet it is essentially (as Professor
Itobison maintains) a corpuscular or atomic doctrine^
and it farther appears to be difficultly reconcilable to
the doctrine of inertia; for how can a finite number of
unextended physical points, though they may be the
centres of intense forces, constitute a finite aggregate
mass? Nevertheless this speculation has been on
the whole favourably received, and in our own time
seems to have been adopted by so eminently practical
a philosopher as Dr Faraday.
(620.) About Dalton’s idea of atoms, however, there can
Dalton’s be n0 doubt. They are, according to his view, pon-
the'subject ^eraWe> indivisible masses, having length, breadth,
and thickness, consequently form. He had distinct
conceptions of their relative weights, distances, and
specific heats. He was particularly fond of depicting
them in diagrams, to which he often refers for a clearer
exposition of his views than he chose to give in words.
A mechanical mixture of gases like the atmosphere is
for him a uniform diffusion of the atoms of each gas
throughout the space occupied by the whole, and
without reference to the position of the atoms of any
of the others. But a chemical compound consists
of molecules or complex atoms, each composed of
two or more ultimate particles of the constituents
firmly united by a chemical force, and these complex
molecules act towards one another exactly as simple
ones might do. The general notion of chemical forces
or affinities (as they were perhaps first called by Geoff¬
rey, a French chemist) appears to have been appre¬
hended in two different senses corresponding to the
atomic or non-atomic theory of body. For the former
proceeds on the assumption of direct attractions or
repulsions {jpush-and-pull forces, as they have been
called) uniting some and tending to separate others,
thus assimilating completely chemical with mechani¬
cal forces. The other school adopts the word affinity
as expressing a mode of action of matter upon matter
totally distinct from that of force producing motion
in its particles, to which it is difficult to give an in¬
telligible form, much more to prove that the assump¬
tion is warranted by the facts.1 In this state of
matters the choice between an opinion perhaps erro¬
neous, and one which assumes no definite shape, can
hardly, to the practical philosopher, remain long
doubtful; when new facts shall have enabled him
to express intelligibly a new hypothesis, it will be
time enough to adopt it.
Dalton's Atomic Theory.—I shall first briefly state (621.)
the general facts or laws to which Dalton gave an uni- ° ghe
versal application, and then briefly refer to the un- miCal com
doubted anticipation of part of them by earlier chemists, bination.
For the sake of distinctness t\\e facts of the atomic theory
may be thus enumerated :—1. That when two bodies
unite, not merely by mechanical mixture but through
a chemical affinity of the elements,—two or more in- ,
gredientsforming a wholewith new properties,—these
ingredients are invariably found to exist in constant
proportions. For instance, the carbonate of lime in¬
variably consists of 44 parts by weight of carbonic
acid and 56 of lime, the slightest addition of either
element remaining uncombined, or only mechanically
mixed with the chemical product. 2. In many
instances, however, more than one chemical combi¬
nation can be formed between two or more elements,
and in the simplest cases, where the elements are
two in number and one remains constant in quantity
whilst the other increases in amount, a fresh che¬
mical union of the particles does not occur until one
of the ingredients reaches precisely double the amount
and in Whewell’s Philos, of Inductive Sciences, vol. i. Xewton’s conjecture is expressed in these words :—“ All things considered,
it seems probable that God, in the beginning, formed matter in solid, massy, hard, impenetrable, moveable particles, of such
sizes, figures, and with such other properties, and in such proportion to space, as most conduced to the end for which he formed
them. And that these primitive particles being solids, are incomparably harder than any bodies compounded of them; even
so very hard as never to wear or break to pieces; no ordinary power being able to divide what God himself made one in the
first creation.” Horsley’s Newton, vol. iv., 260, quoted by Daubeny.
1 A profound and subtle thinker of our own time (Mr Leslie Ellis, of Trinity College, Cambridge) has made a definite suggestion
as to a possible form of chemical forces, viz., that they may not be such as are directly exerted between a particle A and a particle
B, but only by their presence enable A to act on B, or bear the same relation to force (common force) as force in mechanics does
to the motion which it causes. Thus, the science of mechanics would include—1st, Kinematics, or pure motion depending on
equations of the first order ; 2d, Dynamics, depending on equations of the second order ; 3d, Chemical, Vital, &c., forces, depend¬
ing on equations of higher orders. Camb. Trans., viii., 604, &c.
Chap. VI., § 3.]
HEAT (ATOMIC CHEMISTRY).—DALTON.
937
which had chemically combined with the other ; and
if it happen that fresh compounds are formed pos¬
sessing new qualities, then the varying ingredient
reaches 3, 4, or 5 times the amount which it had in
the first combination ; or more generally the propor¬
tions by weight of the combining elements may he
exactly represented by whole numbers. 3. “ If two
bodies combine in certain proportions with a third,
they combine in the very same proportions with
each other.” This is called the law of reciprocal pro¬
portion. Thus, suppose that one ounce of a body A,
saturates or forms a chemical combination with two
ounces of B, 5 of C, and 11 of D ; then if B, C, and D
are capable of combining, it will be in the exact pro¬
portions of the numbers 2, 5, and 11. Hence a single
number being determined for each body, determines
all its possible combinations with other known bo¬
dies. 4. It may perhaps be added as an indepen¬
dent fact, that when complex bodies combine with
other bodies, no matter whether simple or compound,
the combining number of the complex body is the
sum of the numbers representing the constituents.
Thus the combining number of lime is 28 ; but lime
consists of calcium 20 and oxygen 8. So also the
combining number of water is 9 ; but water consists
of hydrogen 1 and oxygen 8 : and the combining
number of hydrate of lime is 37, the sum of the 28
parts of lime and 9 of water of which it is composed.
(622.) The discovery of these laws has been termed by
Partial an- gir John Herschel the most important, after the laws
ticipation mechanics, which the study of nature has vet dis¬
these laws, closed. No slight or transient reputation is due
to him who first clearly apprehended and taught them.
Nor must we be surprised to find several claimants to
a share of the honour. It is the invariable history of
all great generalizations, that they have been partly
anticipated; and it may serve to moderate the self-
esteem of even the greatest discoverers, that however
high may be their individual merits, they are in some
sense the mere exponents of the aggregate know¬
ledge of their contemporaries. The laws of motion
were partially anticipated before the time of Galileo,
and could not have remained much longer undefined;
and even the unparalleled discoveries of Newton
must, in all probability, have ere long been made
piecemeal by the united energy of his contemporaries
and immediate successors. The steam-engine was
not the sole creation of Watt, nor was Davy the first
to apply the voltaic battery to chemistry. In like
manner, Dalton’s laws of chemical combination were
published at a happy moment, which gave them
speedy acceptance with the active chemists of his
day; whilst those who had seen with sufficient clear¬
ness portions of these laws twenty or thirty years
before, addressed a scientific public by no means pre¬
pared to appreciate their value, or to feel a conviction
of their generality. Had Wenzel,1 Higgins,2 and Wenzel,
Richter3 individually apprehended the great impor-
tance of the definite and multiple combining pro- Rlcl1*
portions which they announced,—had they felt the
theory of them to constitute the very foundations of
chemistry,—they would not have rested until they
had verified it in numerous details, and applied it to
the various purposes of speculation and practice, as
Dalton did. But whether from want of energy, or
from ill fortune, their ideas sunk into entire oblivion;
and the ingenuity and social position of Berthollet
were giving a cui’rency to opinions respecting chemi¬
cal forces which tended to undo even the far more
elementary notions of the constancy of elective affi¬
nities, at the time when Dalton’s researches were
unostentatiously brought before the world. His first
insight into the theory of chemical combinations
dates from the year 1803. It was expounded by
him both in conversation and by lectures in 1804,
at which date Dr Thomas Thomson recorded the
results of a conversation held with him at Manches¬
ter, which, three years later (evidently with Dalton’s
approbation), he published in his work on Chemistry.
Finally, Dalton himself, in 1808, announced the prin¬
ciples of his theory at no greater length than five
pages “ on Chemical Synthesis” in his Chemical
Philosophy.
Now, it is to be observed, that Dalton’s views were (623.)
all along expressed in the language of a strictly Ato- Importance
mic theory. Compounds are only chemically com- mic^heory
plete, when one or several atoms of an element com- to the pro¬
bine with one, two, or more atoms of another. Any gress of
superfluity of either element remains uncombined, or chemistry’
mechanically mixed. All the other parts of the laws
of combination readily lead to the same idea, and, in
fact, find in it their simplest expression. There is
no wonder, then, that Dalton firmly believed in the
physical existence of his atoms, and that the new
properties of compounds are due to the peculiar mo¬
dification of the most elementary parts into which
bodies can be divided without a loss of those proper¬
ties, that is, without decomposition. He figured
these elementary molecules by uniting the symbols
of their constituents, and by so doing, may be said
to have laid the foundation of those algebraic sys¬
tems of technical notation, which speak to the eye
only in another way from Dalton’s diagrams, and
which have been of such eminent service to the
chemist. Nor must we think too lightly of a hypo¬
thesis which served so materially to aid in realizing
1 Lehre von der Verwandschaft der Korper, 1777. He shows that in a double decomposition the new compounds are chemi¬
cally perfect.
2 A Comparative View of the Phlogistic and Antiphlogistic Theories, 1789, by Mr William Higgins, points out the multiple com¬
bining proportions of sulphur and oxygen, and of nitrogen and oxygen, but only incidentally. Dr Bryan Higgins, a relative of
Mr W. H., had published, in 1786, a work said to contain the idea of definite atomic combinations.
3 Anfangsgriinde der Stochyometrie, \7§2. He gave a series of numbers representing the combining proportions of different
elements.
VOL. I. 6 c
938
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
a discovery of such magnitude. Dalton’s earlier re¬
searches were far more physical than chemical; and
it is evident that the effort of representing to his
mind, geometrically and atomically, the condition of
mixed gases and vapours, led him to form clear
ideas on the definiteness of chemical combinations.
The delay in publishing his views, no doubt de¬
pended on his desire to present them to the public
in the form of a somewhat wide induction, although
it is certain that his own opinion was fully formed
from a knowledge of only one or two cases of multi¬
ple proportions, and especially the combinations of
hydrogen and carbon. It cannot be fairly urged as
conclusive against the theory of atoms, that cases
occur difficult to reconcile with the author’s formal
statement of it. There is no great theory—not even
that of gravitation itself—which has not met with
similar apparent contradictions.
(624.) The reception of the views of Dalton was some-
tionlrT1*" w^at gradual, yet might be called rapid, considering
England, the obscurity of the author, and his provincial resi¬
dence. The energy of Dr Thomson of Glasgow con¬
tributed more than any other circumstance to com¬
pel the attention of chemists. He personally brought
it under the notice of Wollaston and Davy ; and the
former, who, by his habits of precise thought and ac¬
curate experiment, as well as from his extensive che¬
mical knowledge, would of all others have been the
most likely to see its importance and probability,
was doubly predisposed in its favour by having been
himself for some time in possession of facts illus¬
trating the numerical laws of combination similar to
those which Dalton possessed. Wollaston published
these in the Philosophical Transactions for 1808, in
which he expressly states, that Dalton had antici¬
pated him in the results of bis enquiry into multiple
combinations of elements. Davy, as might have been
expected, was less prepared to accept a doctrine
having the form of a mathematical law ; he did so,
however, after a short resistance. In his Chemical
Philosophy he ascribes most if not all the merit of
it to Higgins, and is supposed to have looked coldly
upon Dalton’s growing fame; but it is gratifying to
add, that in almost his last appearance in public as
president of the Royal Society, when presenting Dal¬
ton with the first royal medal, he should have ex¬
pressed himself in terms of cordial praise.
andFranee ^rance t^ie new doctrine soon spread, notwith-
Gay-Lua- siding its violent contradiction to the theories of
sac’s law of Berthollet. Gay-Lussac was amongst its earliest
volumes, and most enlightened advocates; and he had the
good fortune to add, in 1809, a new law to the
principles of chemical combination, which is, that
the gases, in uniting chemically, combine in equal or
multiple volumes, and when any condensation occurs
after they have united, it amounts to an exact frac¬
tion (-^ orl) of their joint bulk. This was the only
addition made for a very long period to Dalton’s
laws, even if we consider the theory of Isomorphism
and of Substitutions to take the same rank; and as
it evidently includes the idea that the atomic weights
of the gases have a simple numerical relation to their
densities, it confirms Dalton’s views of the great sim¬
plicity and uniformity of constitution of those bodies.
In Sweden the doctrine of definite proportions found
one of its earliest advocates in Berzelius, and his
analyses contributed perhaps more than those of
any other chemist to its perfect establishment.
It is not to be concluded, however, that the atomic (626.)
or theoretical part of Dalton’s laws obtained the same “ Chemical
currency with the conditions of chemical combina- lents
tion which they serve to define. Wollaston and
Prout were perhaps the most favourably disposed
to the doctrine of atoms, though the former invented
the term “ chemical equivalents” to escape from the
theoretic inference, and the latter believed that Dal¬
ton’s law was only a portion of a more complicated
one regulating chemical combinations. Wollaston
even sought evidence in favour of ultimate atoms,
from considerations of a purely mechanical kind,
such as the existence of a limit to the atmosphere
(Phil. Trans. 1822). We may however admit, with
those who have taken an opposite view, that the
finite extent of the atmosphere is consistent with a
continuous mathematical law suitably assumed, and
without reference to atoms at all; if, indeed, we can
imagine a medium varying enormously in density,
yet possessing perfect continuity of body. But we
will not enlarge farther on these almost metaphysi¬
cal considerations.
During the period from his settlement in Man- (627.)
Chester in 1793, to the publication of his Chemical p^^ai
Philosophy in 1808, Dalton was occupied in tuition, history
first in the Mosley Street Institution, where he lec- continued,
tured on mathematics and natural philosophy for six
years, and afterwards, privately, in a very humble
and unpretending manner. His speculations and ex¬
periments gradually became more and more strictly
chemical; and, aware that his atomic theory was to
be the great foundation of his fame, he spared no
pains in illustrating it by numerous analyses. Con¬
temporary chemists have testified to the ingenuity
and fidelity of these. Yet, isolated as he was, and
unacquainted perhaps with those niceties of manipu¬
lation which are suggested by the experience of pro¬
fessional chemists, and rapidly communicated in great
cities, his numerical conclusions were often inexact.
Probably he felt some discouragement from this, at
well as from the indifferent reception of the later parts
of his Chemical Philosophy, in which he had to admit
the inaccuracy of his theoretical scales of heat and
expansion. At all events, his publications became
more scanty and less original, though he was still near
the meridian of life. The reality of his discoveries
had been somewhat coldly acknowledged, and he felt
little temptation to adventure himself in a more bust¬
ling arena, for which his habits and circumstances
seemed to unfit him. Nevertheless, he had been, as
Chap. VI., § 3.] HEAT (ATOMIC CHEMISTRY).—DALTON—GAY-LUSSAC.
939
early as 1816, elected a corresponding member of the
Institute of France—Wollaston being then probably
the only other English name on the list.1 Dalton
found his way to Paris in 1822, and was agreeably
surprised by the distinction with which he was re¬
ceived by the most eminent members of the Academy
of Sciences. Perhaps this first 'personal recognition
of his exalted station, as a man of science, had some¬
thing to do with the tardy adjudication to him four
years later of one of the medals of the Royal Society
of London. In 1830 he was elected one of the eight
associates of the Academy of Sciences in the room of
, Sir Humphry Davy.
(628.) In 1833, at the age of sixty-seven, he received a
tgjf charac' pension from government, up to which time he had
maintained himself in the way already mentioned,
with the utmost simplicity and contentment. Even
in his lifetime it was impossible for his eulogists
to forbear from some reference to this essential part
of his really philosophic character. “ Mr Dalton
has been labouring,” says Sir Humphry Davy, “ for
more than a quarter of a century with the most dis¬
interested views. With the greatest modesty and
simplicity of character, he has remained in the ob¬
scurity of the country, neither asking for approba¬
tion, nor offering himself as an object of applause.”
“ There is little doubt,” says Dr Thomson, “ that
Mr Dalton, had he so chosen it, might, in point of
pecuniary circumstances, have exhibited a much more
brilliant figure. But he has displayed a much more
noble mind by the career which he has chosen ;
equally regardless of riches as the most celebrated
sages of antiquity, and as much respected and be¬
loved by his friends, even in the rich commercial
town of Manchester, as if he were one of the greatest
and most influential men in the country.” All who
had the good fortune to know him personally—to see
him, as the writer of these pages has done, in his
modest school-room, and surrounded by his unpre¬
tending apparatus—will own that these eulogies are
and death, not overdrawn. His latter days were spent in cheer¬
fulness and comfort; he expired on 27th July 1844,
having nearly completed his seventy-eighth year.
(629.) The philosophical character of Dalton may be
Dalton’s briefly summed up. He had immense vigour of con-
cai charac- ception, and an ardent love of truth. . He was tho-
ter. roughly devoted to the pursuit of science during his
long career, and he evidently sought and expected
no higher reward than the insight which he obtained
into the laws of nature. His mind, like his frame,
was of a strongly masculine character, and happily
exempt from nervous sensibility and other like in¬
firmities of genius. Whilst he held his own opinions
with tenacity, and criticised freely those of his op¬
ponents, there is not a trace of acrimony in any
of his writings ; and he always spoke in terms of
high respect both of those who pursued science in a
similar direction with himself, and (what was more
difficult) likewise of those who, having the good for¬
tune to hold more conspicuous positions, showed him
the smallest degree of kindness, which he always
gratefully acknowledged. He was unlike Black and
Cavendish, in the rapidity with which he seized on a
few isolated facts, and made them the basis of an
inference of great generality; this, indeed, was his
leading characteristic; and he differed from them
equally in the boldness with which he claimed from
the public a general acceptance of his conclusions.
Some of his inferences were unguarded enough, and
have not been confirmed; and the reception of what
were correct was naturally delayed by the evident
facility with which his theories were shaped in his
own mind. Most of his papers appeared in rapid
succession ; only the Atomic Theory was brought
with some evident hesitation before the world. In
all this we see the results of a vigorous imagination,
united with great perseverance, in working out an
idea. The imaginative element would have been
more under control had his education been of a less
irregular kind. We see the effect of an opposite
turn in his eminent predecessors just named. They
would have done more, had they trusted more. Dal¬
ton’s discoveries may be said to have terminated at
the age of forty. Though he laboured for thirty
years after, the conceptive faculty seems to have
spent itself in its earlier efforts.
Joseph Louis Gay-Lussac, an eminent French ^
chemist and physicist, contemporary with Dalton, Gay-Lus-
has been mentioned in the course of the present sec- sac—che
tion, as having discovered independently the equal "l181 af^
dilatation of the gases, and also a law of their com- ^
binations in connection with their volumes, which
was peculiar to himself. Besides these researches,
science owes many useful observations in physics to
his energy and talent, which, in the origin of his
career, promised more of originality than his ma-
turer life perfectly fulfilled. He was born in the old
province of Limousin in 1778, and became the pupil
of Berthollet in chemical researches, and was one of
the earliest and most active members of the Societe
d’Arceuil. In physics, he was the collaborator of
MM. Biot, Humboldt, and Laplace. With the first Remark-
of these philosophers he made his earliest experi- able bal-
ment in aerostation, which he repeated alone on theloon ascent-
16th September 1804, when he attained the amaz¬
ing height of 7016 metres (23,019 English feet), an
elevation previously unattained, and which in the
course of the succeeding half century has only twice
been touched, or exceeded by a small quantity.2 3 Con-
1 So stated by Dalton himself by Dr Henry, p. 163) ; but I suspect some misapprehension. Considering the importance
attached to these nominations, it is to be regretted that it is at all times difficult to ascertain who are, or have been, associates
and correspondents of the Academy of Sciences.
3 Once by MM. Bixio and Barral in 1850, and once by Mr John WelsK ;n 1852.
940
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
sidering the novelty of the experiment in 1804 (only
twenty-one years after Montgolfier’s first successful
experiment), this fact speaks strongly for his courage
and zeal. These ascents were also the first undertaken
with strictly scientific aims, and the observations made
were highly interesting in connection with the decre¬
ment of temperature in the atmosphere, with the uni¬
formity of composition of air at all heights, and with
the question of whether the magnetic force of the
earth diminishes at such elevations. This last en¬
quiry was not conclusively answered.
(631.) With M. de Humboldt he made observations on
terrestrial magnetism in Italy, and on other subjects. Miscella-
By desire of Laplace he studied the facts of capillary neous ex¬
attraction. In more immediate connection with the P®”ment3
subject of the present chapter, he made some valu- Lussac"
able experiments on hygrometry, on the mechanical
properties of vapour of different kinds, and on the
specific heat of the gases. His fame, however, mainly
rests on the two investigations to which we previously
referred, and on the results of his balloon journey.
His later years were devoted to practical enquiries
connected with chemistry, and to his official duties at
the Mint. He died at Paris on the 9th May 1850. His death.
(632.)
Thomson,
Count of
Rumford.
(633.)
His early
history
and studies.
(634.)
Enquiries
into the
economical
applica¬
tions of
heat.
§ 4. Rumford.—Economical applications of Heat.—Point of Maximum Density of Water; Hope.
—Friction as a source of Heat. Theory that Heat is convertible into Mechanical Energy ;
Mr Joule.
The name of Thomson, Count of Rumford, de¬
serves a passing notice in the history of the physi¬
cal sciences, if not for the absolute importance of
his discoveries, at least as an instance of a class of
benefactors to mankind at once in a physical and in¬
tellectual point of view. He was altogether in ad¬
vance of his age in the application of correct theory
to the improvement of the social condition of the
lowest classes ; and many of his experiments, and,
indeed, discoveries, seem now at once so simple and
so familiar, that we are apt to forget how entirely
original they were sixty years since.
Sir Benjamin Thomson, an American by birth, a
British knight, and a Bavarian or rather Austrian
count, wras born in the United States in 1753, and
passed his earlier years almost entirely at military
stations during the American war, being engaged
on the British side. After the establishment of in¬
dependence, he quitted his country for ever; came
first to England, -where he was well received, and
proposing to enter the Austrian service, he proceeded
as far as Munich, where, having become known to
the elector of Bavaria, he was induced to settle ;
and having received different civil and military ap¬
pointments, he devoted himself for a series of years
to the improvement of the social condition of that
capital. He introduced great improvements into the
management of the army; the mechanical and chemi¬
cal departments of the artillery had a peculiar charm
for him ; they were conducted on strictly scientific
principles, and, in return, were made to contribute
important results to science. His experiments on the
heat of friction, deduced from the boring of cannon,
are amongst the best we possess ; and they led him
to results of considerable theoretical importance to
which I shall presently refer.
But his most serviceable efforts on behalf of man¬
kind were in the treatment of the mendicant classes
with which Munich then swarmed. Salutary views
of the importance of industry, order, morality, and
public economy, were most happily united to a
happy versatility of talent in physical research, to
unwearied patience and great liberality, in effecting
one of the greatest social reforms on record. The
strict statistics of a great house of industry were
ascertained with reference to the most seemingly in¬
significant details, and, in particular, all the appli¬
cations of Heat to the physical wants of mankind
were studied with equal assiduity and success. The
warmth of clothing was traced to the amount of still
air entangled amongst its fibres,—the dissipation of
heat, whether from a thermometer or a kitchen boiler,
was classified under radiation, conduction, and con¬
vection, the last and often most important of which
(signifying the influence of currents in liquids and
gases in conveying heat by the changing density of
their parts) had hardly before been recognised, or at
least made the subject of formal experiment,—the
effective heat due to the combustion of different kinds
of fuel, tested by a calorimeter of his own invention,
—the economy of light based on an investigation of
the properties of flame;—these were but a few of
the trains of enquiry, of which his Mendicity House
was the primary object. Charity and science went Practical
hand in hand ; and when we award to Watt the benefits re-
highest honours for an invention which enabled him sultinS'
to create mechanical force at an economy of two-
thirds of the coal previously consumed, shall we
deny Rumford a civic crown for having so improved
the methods of heating apartments and of cooking
food, as to produce a saving in the precious element
of heat, varying from one-half to seven-eighths of the
fuel previously consumed ?x When we consider the
enormous price of wood in nearly every part of the
Continent, the destruction of forests which has oc¬
curred, and the consequent injury to the climate, as
1 In the hospital of \ erona he reduced the consumption of wood to one-eighth. Some one wittily said of Rumford, that he
would not rest until he had cooked his dinner with his neighbour’s smoke.
HEAT.—RUMFORD—HOPE.
941
Chap. VL, § 4.]
(635.)
Different
experi¬
ments.
(636.)
Dr Hope on
the maxi¬
mum den¬
sity point
of water.
well as to the material wealth of many districts, we
are disposed to give Rumford a higher place than has
generally been accorded to him. Had his excellent
principles been universally carried out, some millions
sterling would have been saved to every large state
in Europe. Fontenelle characteristically says of a
certain savant, who made experiments on nutrition,
with a view to carry fasting to the utmost practicable
extent, that his researches had the double aim of
a place in heaven and in the academy. Cuvier, who
tells the anecdote in his Eloge of Rumford, adds,
that the latter had a truer claim to the questionable
compliment. That science is surely not despicable
by which a pound of wool, of fuel, or of food, can he
made to go one-half farther than before in warming
the naked and in feeding the hungry.
All Rumford’s experiments were made with admir¬
able precision, and recorded with elaborate fidelity,
and in the plainest language. Everything with him
was reduced to weight and measure, and no pains
w'ere spared to attain the best results. His experi¬
ments on heat, and the properties of bodies in con¬
nection with it, are the most important. He first
applied steam generally in warming fluids and to the
culinary art. He maintained the paradox of the
non-conducting power of liquids, which, though prac¬
tically true, appears not to be rigorously so. He
contrived many ingenious instruments; but his ther¬
moscope, identical with Leslie’s differential thermo¬
meter, was probably of later invention, if not in
some measure borrowed from it. In like manner his
proofs of the maximum density point of water were
unquestionably suggested by Dr Hope’s beautiful ex¬
periment, although this derives its meaning from the
laws of convection, which Rumford first established.
That water expands in bulk below the temperature
of 39° or 40° Fahr. until it freezes, is a fact which
had been asserted since the middle of the seventeenth
century. But for 150 years its great improbability,
and the unquestionable uncertainty introduced into
the result by the irregular expansion of the contain¬
ing vessel or glass of the thermometer, enabled scep¬
tics in every generation to withhold their assent. Per¬
haps the last who doubted was the illustrious Dalton.
He allowed himself however to be convinced by Dr
Hope’s experiment, in which the temperature of the
denser and rarer water is measured by two thermo¬
meters placed at the bottom and top of a cylindrical
jar, and nothing interferes with the natural tendency
of a fluid to arrange its particles according to their
specific gravity, the lighter resting on the heavier
ones. It is to be regretted that Hope did not pro¬
secute original enquiry, for which the conception of
this experiment, and the mode in which he conducted
it,1 show that he had excellent qualifications. Hope
was first the colleague, then the successor of Black
in the chair of chemistry in Edinburgh; and in his
time probably the most popular teacher in Europe
of that science. He died on the 13th June 1844,
in the seventy-eighth year of his age.
Rumford’s name will be ever connected with the (637.)
progress of science in England by two circumstances ; Rumf°rd
first, by the foundation of a perpetual medal and R0yaf7n.
prize, in the gift of the Council of the Royal Society stitution.
of London, for the reward of discoveries connected
with Heat and Light; and secondly, by the estab¬
lishment, in 1800, of the Royal Institution in Lon¬
don, destined, primarily, for the promotion of original
discovery, and, secondarily, for the diffusion of a taste
for science amongst the educated classes. The plan
was conceived with the sagacity which characterized
Rumford, and its success has been greater than could
have been anticipated. Davy was there brought into
notice by Rumford himself, and furnished with the
means of prosecuting his admirable experiments.
He and Mr Faraday have given to that institution
its just celebrity with little intermission for half a
century.
Rumford spent his later years in Paris, where he (638.)
died in 1814. The estimation in which he was then Rumford’s
held may be judged of from the fact, that he was ^
one of the eight foreign associates of the Academy
of Sciences. He wTas very capable of having done
more for science: the versatility of his talents, the
accidents of his early life, and the strong hold which
principles of philanthropy and public utility always
exerted over him, account for the absence of more
sustained and erudite researches. But in those very
particulars he deserves to be cited as a practical phi¬
losopher, as to many things in advance of his age,
and a benefactor both to science and to mankind.2
In the history of pure science Rumford will be (639.)
chiefly remembered by his espousing the (not new) H.1S °P1‘
theory that heat consists in a motion of some kind t}ie nature
amongst the particles of matter, in opposition to the of heat im-
opinions then so prevalent amongst chemists, which portant.
almost tended to regard it as an element capable of
forming combinations. Rumford’s view was maiidy Derived
based on the facts of friction, which he showed to be ffom exPe*
irreconcilable with the notion of a change in the spe- °n
cific heat of the abraded matter, and to be seemingly
inexhaustible so long as the force producing friction
is continued. His conclusion was, that the heat
then generated cannot be a substance, but an affec¬
tion of body of the nature of vibratory motion. The
amount of heat evolved in boring cannon is very
1 Edinburgh Transactions, vol. v.
2 Rumford married (for the second time) Lavoisier’s widow; his daughter (by his first marriage) became Madame Cuvier.
Hence Cuvier’s Eloge of Rumford contains the most authentic particulars of his life. Madame Rumford survived until a few
years since, residing at Paris, where she formed a link between the savans of the age of Lavoisier, and those of the middle
of the nineteenth century.
942
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
great, an operation with which, as we have seen, he
was professionally connected. In one experiment, a
steel-borer pressed with a force of 10,000 lbs. against
gun metal, and revolving 32 times in a minute, gene¬
rated in 2£ hours the heat necessary to boil 18f lbs.
of water. It is probable that Rumford carried his
views so far as to infer a necessary and constant
relation between the quantity of heat generated and
mechanical action expended; and if we take an esti¬
mate of horse-power more conformable to reality
than the nominal horse-power of Watt (33,000 lbs.
raised 1 foot in the minute, which is too great), we
shall find a tolerable approximation between his re¬
sults and those now generally admitted. Davy fa¬
voured Rumford’s theory, hut the mechanical ques¬
tion remained for 40 years almost unconsidered.
(640.) At length, about 1845, Mr Joule of Manchester en-
Subject re- flavoured to establish a rigorous connection between
Mr Joule. tlie mechanical effort expended and the heat gene-
Mechanical rated by friction; and he appears to have satisfac-
effect of torily established {Phil. Trans., 1850) that in the
heat* case of water agitated by beaters, the work expended
by the fall of 772 pounds through 1 foot is capable
of raising the temperature of a pound of water by 1° of
Fahrenheit.1 Mr Joule’s experiments and inferences,
however, go much farther than this, namely, that in
all circumstances where heat is generated, it is at
the expense of a precisely similar equivalent of me¬
chanical effect; and conversely, that mechanical effect
is never used up, without a corresponding evolution
of heat, and that this is the case whatever be the
fluids or other substances employed. Thus in the
steam-engine the possible efficiency of the engine is
only limited by the mechanical effort due to the heat
given out by the condensed steam. So the heat given
out by compressed air represents the force expended
in compression; and even the heat produced by voltaic
or magnetic electricity is that which corresponds to
the work it might do. A step farther leads to the
equivalence of heating effects by chemical combina¬
tion to the amount of energy which, differently di¬
rected, might have been realized in the shape of
work; and though a larger induction is still required
to justify all the conclusions which the zealous pro¬
mulgators of this comparatively new “ mechanical
theory of heat” have advanced, it cannot be doubted
that there is a basis of important truth in the matter
which well deserves farther enquiry.
§ 5. Sm John Leslie.—Establishment of certain Laws of Radiant Heat.—Pictet—Prevost.
(641.) The fact that heat is radiant, or passes through
Sir John Space in the manner of light, apparently disengaged
progress of from any material vehicle, became known at an early
the science period. Porta in the sixteenth century, and the Flo-
of radiant rentine academicians in the seventeenth, had reflected
beat‘ heat by mirrors. Marriotte and Newton respectively
assigned some of the laws which characterize it.
Lambert, in the middle of the last century, made
some real advances, but it was not until the very
close of that period that heat in the radiant form was
carefully and systematically studied. The group of
philosophers simultaneously engaged on it consisted
of Leslie, Rumford, Herschel, Pictet, and Prevost.
The two last named were earliest in point of date ;
but as we owe to Leslie by far the ablest series of
experiments, and which for many years, and even to
the present time, have formed part of the body of
science, we shall connect his name principally with
this section.
H's^arl ^0HN Leslie, born in 1766, completed his
studies • studies at a very early age in the University of St
Andrews. From boyhood he was remarked for a
decided and independent turn of character; and as
his favourite studies were mathematical, he for some
time pursued them to the exclusion of the classics.
Ultimately, however, he attained also to a respect¬
able knowledge of these, and by his strong natural
talents, and his love of reading, he acquired an im¬
mense stock of information on all sorts of subjects.
This he displayed not only in his conversation, but
also in his writings on technical and purely scienti¬
fic matters, in which he frequently introduced with¬
out much apology illustrations from his miscella¬
neous reading, and even metaphysical disquisitions.
As is frequently the case in persons addicted to (643.)
natural philosophy, his first original researches were an(i essays
connected with mathematics. Playfair, who wason ™athe'
eighteen years his senior, encouraged and directed electricity,
him; Ivory, who was almost his contemporary, and
also his fellow-student at St Andrews, was per¬
haps no less influential in confirming his geometrical
tastes. The former communicated Leslie’s first ori¬
ginal paper to the Royal Society of Edinburgh in
1788. It was on Indeterminate Equations, and was
printed in their Transactions. Down to this period
we have no record of his being engaged in original
experiments ; but it is probable that such was the
case, for in 1790, and the following years, we have
evidence not only of his having speculated on subjects
of natural philosophy, but also that he had made
experiments intended to confirm or refute prevailing
theories. A paper on Electrical Theories was read
to the Royal Society of Edinburgh, which, finding
them reluctant to print, he withdrew, and he only
1 To Rumford, I believe, is due the attempt (in conformity with this view) to ascertain the heat developed by the friction of
fluids, for instance in churning (which, I think, was one experiment proposed by him), but I have not been able to find a
reference to it amongst his scattered writings.
Chap. VI., § 5.]
HEAT.—SIR JOHN LESLIE—PICTET.
943
(644.)
Travels.
(645.)
Publishes
his Essay
on Heat.
published it more than thirty years after, when cer¬
tainly it was not calculated to advance science in a
perceptible degree. An essay on Heat and Climate,
read at the meetings of the Royal Society of London
in 1793, had not a more favourable reception ; and
though published twenty-six years later in Thomson’s
Annals, it was refused a place in the Philosophical
Transactions. The author, no doubt, attributed these
rejections to the boldness with which he criticised
opinions currently received, and to the novelty of
the views which were shadowed forth ; but something
is, no doubt, to be allowed for the real immaturity of
these works, the involved and even inflated style in
which they were written, and the questionable evi¬
dence for some of the conclusions. In these, and in
some subsequent scattered papers in Nicholsons
Journal, we observe, with all the faults, yet many of
the merits of those researches which afterwards made
him justly famous. We find acute observation, in¬
genious, if not close reasoning, considerable inven¬
tiveness in imagining experiments and in constructing
apparatus, and a general tendency to express physi¬
cal laws in a mathematical form. It must be con¬
fessed, that these merits were united to a good deal
of dogmatism, and a somewhat supercilious judgment
of persons eminent in science whose years and at¬
tainments should have commanded respect. This,
however, is a fault which many ardent students not
very conversant with the world have had abundant
occasions to regret at leisure. Whether or not he
believed Sir William Herschel to have had some
share in the refusal of his paper by the Royal So¬
ciety I do not know, but it is difficult, on other
grounds, to understand the bitterness with which he
expressed himself as to that eminent person, in con¬
nection with his experiments on heat.
One of the circumstances which most contributed
to encourage Mr Leslie’s taste for experiment, was
his engagement for above two years as tutor and
companion in the family of the ingenious Mr Wedg¬
wood. Another was the opportunities which he
found or made for himself of foreign travel. With
or without companions he visited, in the early period
of his career, America, and most of the northern
countries of Europe, particularly Holland, Germany,
Switzerland, Sweden, and Norway. He also medi¬
tated a journey to Egypt and the East, a project
reluctantly abandoned, and to which he reverted even
in the last years of his life ; but it was never carried
into effect. Nothing, perhaps, fosters so surely a
taste for science as such extended tours ; and the
acquaintance made under the most agreeable cir¬
cumstances with foreign philosophers, and the fami¬
liarity gained with their language and experiments,
contributes to it in no small degree.
We have now come to the period of Mr Leslie’s
life when his character and position became esta¬
blished, the first by the publication of his Experi¬
mental Inquiry into the Nature and Propagation of
Heat, in 1804; the latter by his appointment to the
chair of mathematics in the University of Edinburgh
in 1805. I shall first say a few words on his cha¬
racter as a mathematician.
Mathematics were, as has been stated, his earliest (646.)
pursuit, and he cultivated them with great industry Mathemati-
and success. His adviser, Playfair, was attached writ'
to the methods of the foreign mathematicians; and 1 SS'
Leslie no doubt acquired from him, as well as from
his continental friends, a taste for the notation of
Leibnitz, then hardly employed in this country, but
which he uses in his work on Heat, and elsewhere.
Nevertheless, his real preference appears to have
been decidedly geometric. He almost always pre¬
fers demonstrations, whether in mathematics or na¬
tural philosophy, in the manner of Huygens and
Newton. He could hardly be called a discoverer in
mathematics; but his work on Geometrical Analysis
and the Higher Curves shows much taste and know¬
ledge, and is justly commended by Chasles and other
foreign writers. His attempt to replace Euclid’s Ele¬
ments by a new work on Elementary Geometry was
not more successful than such attempts have usually
been.
Unquestionably, the bent of Leslie’s mind was (64L)
to physical research, in which he showed a peculiar Importance
talent; and his selection of Heat was, as we have of the sub-
hinted, well-timed; since there appeared a con-Ject of ra-
vergence of attention to the subject, such as usually diant heat’
heralds some eminent discovery. The doctrines of
heat in combination, of which we have already spoken,
had engaged the attention of Black, Cavendish, and
Lavoisier; the subject of meteorology, in which Leslie
took the greatest interest, was becoming a science in
the hands of He Saussure and Deluc; whilst Pictet
repeated (without being aware of the anticipation)
the curious observation of Porta on the apparent con¬
centration of cold by a concave miiTor. As this ex¬
periment really opened anew the subject of radiant
heat, we shall dwell for a moment on Pictet’s labours
and their results.
Geneva was at this time nearly in the zenith of its (648.)
reputation as a nursery of the sciences. The most ^lctet of
l ^ . Irencva
eminent and independent of its citizens were proud
of being also amongst its instructors, and the office
of professor was then, as it still is, considered one of
the most honourable in the state. About 1790 He
Saussure, the most eminent physical geographer of
his time, was in the vigour of his intellect, and amongst
his friends and coadjutors Marc-Auguste Pictet
held a conspicuous place. The latter was professor
in the Academy, and being a person of popular man¬
ners and great information, was known and esteemed
by the learned throughout Europe. He was the
author of numberless papers in a scientific jour¬
nal which he edited ; but his work on fire—Essai sur
le Feu—published in 1791, was his principal pub¬
lication. It contains some good observations on latent
and specific heat; and on the power of different kinds
944
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(649.)
Prevost—
moveable
equili¬
brium of
heat.
(650.)
Leslie’s
Essay on
Heat—Dif¬
ferential
thermome¬
ter.
of surfaces to reflect and absorb it. He noticed the
different heights at which a blackened and a bright
thermometer stand even when exposed to common
daylight; but so far as I have observed, he did not
distinguish the effect of colour in absorbing heat when
that heat is accompanied by light or the reverse; and,
indeed, this portion of his work stops short on the
threshold of most interesting enquiries. He showed
that radiant heat travels with great velocity, and ob¬
served the heating and cooling of thermometers in
exhausted receivers. His work also contains obser¬
vations on hygrometry, on some points of meteoro-
logy, and on the heat of friction. Indeed, its chief
fault is embracing so many topics in so short a com¬
pass, thus preventing him from thoroughly examin¬
ing any one of them. To Pictet is due the establish¬
ment of meteorological observations at the convent
of the Great St Bernard, which are amongst the
most interesting which have ever been made, and
which are still continued. He died in 1825, at the
age of seventy-three.
The interesting experiment of the reflection of cold
led Pierre Prevost, one of Pictet’s colleagues, to
devise the theory of “ the Moveable Equilibrium of
Heat.” His idea is, that heat is a substance associated
with bodies, of a highly elastic nature, and continu¬
ally given off from them in proportion to their tem¬
perature, which may represent the tension of the
imaginary elastic fluid. When the temperature of a
body is stationary, it is (according to this view) be¬
cause it receives by radiation from surrounding bodies
exactly as much heat as it parts with in the same
way. The general structure of this theory was sus¬
tained by the experiments of Leslie, and by some
later ones on the law of cooling by Dulong and Petit,
which, indeed, realize it in a remarkable manner.
Prevost first published his ideas in 1791, in the
Journal de Physique, and afterwards in a special
work. Prevost wras a man of an active and vigorous,
rather than profound intellect. He was a foreign
member of the Royal Society, and died in 1839, at
the advanced age of eighty-eight.
We now come to speak of Leslie’s important Essay
on Heat which received from the Royal Society the
distinction of the Rumford medals, and which pro¬
cured for him a European reputation. It is a work
difficult to analyze, from the very fact, that its con¬
struction is fragmentary, and its arrangement desul¬
tory and obscure. Our limits will only allow us to
mention the methods of research and their chief re¬
sults. As a thermoscopic instrument, he used a
modification of the common air thermometer (which
last had been employed by Pictet), which, having two
balls at a certain distance, connected by a bent tube
containing a coloured liquid, showed the difference of
temperature of the balls; and being hermetically
closed, was free from the disturbing variation of at¬
mospheric pressure. This he called the differential
thermometer. A similar instrument had been de¬
scribed by Sturmius in the seventeenth century.
Whether Leslie had any previous knowledge of this
does not appear; but, as Dr Young very correctly
observes in one of his anonymous critical articles,—
“ The principle of the differential thermometer is too
simple to be called an invention, and it is only by
its ingenious application that Professor Leslie has
made it an object of attention.” He usually em¬
ployed as a source of heat a canister of block tin,
filled with boiling water, and having sides with dif¬
ferent surfaces. The radiating or emissive effect ofEmissive
these surfaces was measured by the rise of the ther- of
mometer exposed to their successive mnuence in the8urfaces
focus of a metallic reflector. The result showed a
great variety of effect, varying from 100 when the
surface was blackened, to 12 when it was of polished
metal. The absorptive power of surfaces to non-
luminous heat is also in exact proportion to their
emissive power—a property which seems essential
for preserving the equilibrium of like temperatures.
Another and not less important law clearly esta- (651.)
Wished by Leslie was this, that the radiation of ^ea^^^na[ion
from a plane surface takes place with unequal force of rad;ant
in different directions.1 When the specific heating heat,
power or density of the calorific rays is estimated in
a direction perpendicular to the surface from which
it emanates, it is found to be a maximum. At any
other angle with the surface, it varies as the sine of
the angle. This law (which Fourier showed later to
be necessary for the equilibrium of temperature)
obtains also in the case of light. Hence the appa¬
rent specific brightness or warmth of a surface is
the same under whatever angle it is viewed with re¬
ference to the plane of the surface, which, when
placed obliquely, contributes rays from a larger ex¬
tent of surface, owing to the foreshortening, but being
weaker in the same proportion from every point, the
aggregate effect is the same. Some interesting ex¬
periments were made on the number of coats of
isinglass necessary to effect a complete transformation
of the metallic into the gelatinous surface, which was
found to be considerable; and, in like manner, the
reflective character of metals was only very gradu¬
ally destroyed by varnishing. This observation,
rightly interpreted, showed that some solids are per¬
meated by radiant heat, a conclusion which Mr Leslie
utterly rejected.
Another fundamental experiment less decisively (652.)
proved was, that the law of radiation varies inversely^® 5nverge
as the square of the distance. Perhaps the mostSqUareof
convincing, as well as the simplest proof of this has the dis-
been given more recently by Melloni. If a delicatetance-
thermometer or other apparatus for measuring radi¬
ant heat be confined in a case, so as only to admit
rays coming within a definite angular space—and if
1 This result had already been anticipated by Lambert; Pyrometrie, p. 197.
Chap. VI., § 5.]
HEAT.—SIR JOHN LESLIE.
945
(653.)
Influence
of colour
on radiant
heat.
(654.)
The laws of
cooling un¬
der rarious
circum¬
stances.
Leslie’s
peculiar
views on
the propa¬
gation. of
heat.
the instrument he placed in front of an indefinite
plane (such as a wall) hotter than itself—the rise of
temperature will he precisely the same, whatever be
the distance at which it is presented to the heated
surface.
The influence of colour on the heating of bodies
was considered by Leslie in an original manner. It
was found to he effectual only when the radiations are
luminous. A thermometer painted black or white
(provided the texture of the surface he the same)
parts with its heat, and also absorbs the heat de¬
rived from such a source as boiling water, in an al¬
most equal degree. The effect depends chiefly on the
degree of polish or condensation of the surface. But
with luminous sources of heat the case is widely dif¬
ferent. This subject had been carefully considered
previously to the date of Leslie’s work by Sir W.
Herschel, who had studied the absorbing power of
different colours on the sun’s rays. Black and white
form the two extremes, and Leslie availed himself of
this principle to construct his photometer, which cer¬
tainly (whatever may he its defects) is an elegant mo¬
dification of the differential thermometer. It is an
instrument having one ball of black, the other of
pellucid glass, and united by a tube of the form of
the letter U, containing sulphuric acid tinged red as
an indicator. As the texture of the surfaces of both
balls is the same, dark heat is equally absorbed by
both, and the indicating liquid remains stationary.
But in the sun’s rays, or even in common daylight,
the dark hall becomes most heated; and it is not
unreasonable to conclude, that when the source of
heat remains the same, its variations of intensity are
correctly shown. Leslie, however, erred in consider¬
ing that it was applicable to measuring light differing
in origin and quality on a comparative scale; and
this error he unfortunately persevered in, after un¬
questionable experiments had shown its fallacy.
The Essay on Heat contains an elaborate and
ingenious research into the law of cooling of bodies,
including the effects of mass, surface, contact of air,
currents of air, and likewise of inclosure of the cool¬
ing body in successive envelopes or thin cases ; and
the author ingeniously compared the results of actual
experiment with formulae based on principles more
or less theoretical. But a fundamental error unfor¬
tunately runs through all this research, and shows
in a striking manner the fatal influence of theo¬
retical preconception steadily maintained through a
course of experimental enquiry. He starts with the
notion, that the presence of air is essential to the
propagation of Heat, generally called “ radiant.” In
fact, for radiation he usually substitutes the word
“ pulsation,” and ascribes the effect of surface in mo¬
difying the cooling of bodies to its faculty of trans¬
mitting pulsations or tremors, more or less readily,
to the vehicle of the air. He was indeed compelled
to admit that air had a double agency; one “ abduc-
tive,” as it draws off heat by contact and by what is
VOL. i.
generally called “ convection,” that is by currents
which the communication of heat itself produces ; the
other, “ pulsatory,” which corresponds to what is
usually termed radiation, but which Leslie persisted
in believing to be due to tremors propagated in air,
after the manner of sound, and with the same velocity.
In the concluding chapter of the work before us he
considers the cooling effect of different gases, and of air
of different degrees of rarefaction ; and this last ex¬
periment might, one would have thought, have satis¬
fied him of the fallacy of his opinion ; since, taking
his own numbers, when air is rarefied 1024 times, the
“ pulsatory energy” is only diminished one-third part.
In fact, it appears as if his work broke off abruptly,
when the course of observation became irreconcilable
with the opinions advanced in the early part of it.
After this analysis of Leslie’s greatest contribution (655.)
to science, I cannot afford space to dwell upon his His- minor
minor inventions. I pass over them, however, with
the less regret because they have been fully dwelt experi-
upon in his “ Dissertation,” of which the present is a ment.
continuation, and in his articles on Cold and Meteo-
rology in the Encyclopaedia. The most original and
important of these was his very beautiful process of
producing ice in quantity by the cold of evaporation,
in the receiver of an air-pump ; rendered effectual by
his ingenious use of absorbent surfaces for with¬
drawing the vapour. This experiment was completed
in 1811, and attracted much attention. It was con¬
nected with his researches on hygrometry, to which
he also adapted his differential thermometer. But
in the development of this difficult theory, he was
less successful, nor indeed could he well he so, whilst
he adhered to the old opinions respecting the affinity
of air for moisture.
Having filled the Mathematical Chair from 1805 to (656.)
1819, Leslie was in the latter year translated to that close his
of Natural Philosophy, vacant by the death of Play- career-
fair. He had a good collection of apparatus, and de¬
vised many ingenious experiments. In 1820, he was
elected corresponding member of the Institute of
France, and died on the 3d November 1832, at the
age of 66, having received the honour of knighthood,
on the recommendation of Lord Brougham, hut a few
months before.
In closing this brief sketch of Sir John Leslie’s (657.)
career, we cannot fail to observe the combination ofIlis ph'lo-
unusual powers with unusual drawbacks to their
complete and vigorous exertion. Whilst he had the jn some
chief merits, he had also the most serious defects, of points de-
the self-formed student. He was ardent and ambi- fective
tious in the pursuit of knowledge. He must have
been for many years a hard, if not a methodical stu¬
dent ; he united good mathematical knowledge with a
real love of experiment; he was gifted with a strong
memory, and confident in the exercise of all his
powers. Why, with so many advantages he did not
achieve more, nor put forth even what he did to
6 D
946
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
greater advantage, was mainly because he yielded to
the guidance of an imagination which often carried
him into fanciful speculation, yet which was strangely
united with dogmatism in maintaining what he had
once maintained, and a disposition to accuse others of
misinterpreting nature, whenever they arrived at con¬
clusions inconsistent with his own.
In such sciences as those which he chiefly culti¬
vated,— sciences eminently progressive, imperfect,
and dependent on experimental proof,—a just appre¬
ciation of the labours of others is one of the most
essential parts of the philosophic character, whilst
an absence of it infallibly condemns the dogmatic
theorist to be gradually left behind, even in the paths
which he had at first trod with the greatest distinc¬
tion. With few exceptions, Sir J. Leslie carried his
scientific views of 1804 with him to the grave. The
possibility of the passing of heat, except solar and
highly luminous heat, through any solid body, such
as glass, though proved by Maycock, De la Roche,
and Powell,—the existence of dark heating rays in the
sunbeam, less refrangible than the red, demonstrated
by Herschel, and afterwards confirmed by many
others,—the doctrine of gases and vapours as laid
down by Dalton,—the maximum density point of
water shown so ably by Hope and Rumford,—the
existence of climates in the arctic regions of which
the mean annual temperature does not exceed 0° of
Fahrenheit, proved by Parry and his successors,—
all these, and many other demonstrated truths in his
own peculiar walk of science, were, we fear, practi¬
cally ignored by him throughout life. (659.)
But we willingly leave the ungrateful task of indi- Merit ofhis
eating defects. Let us recollect rather with pleasure taiPreimeU*
how much we owe to his beautiful discoveries. It is searches,
perhaps not an insignificant test of their originality,
that though they were generally adopted (at least to
the extent which his own experiments justified), Les¬
lie’s observations were but rarely repeated, and that
only in the way of general confirmation and illustra¬
tion. I mean that for a great many years the path
which he had opened, and the methods which he de¬
scribed, were not seized upon by others, as leading to
a sure course of discovery. Until the time of Dulong,
his experiments on cooling were perhaps never care¬
fully resumed, and a very great number of his sub¬
jects of enquiry were only taken up thirty years after
their publication, as we shall see in a future section.
The observations of Herschel on the Refrangibility (660.)
of Solar Heat, I shall include in the notice of the
experiments of Berard and De la Roche, to which
we shall presently turn.
§6. Fourier.—Mathematical Theory of the Conduction of Heat. Lambert; Poisson.—
Temperature of the Earth and of Space.
(661.) It is stated by Arago, that when the Academy of
Theory of Sciences, above a century ago, proposed as a prize sub-
tio^of heat ject’ <<^ja Nature et la Propagation du Feu;” adding,
—Lam- “ la question ne donne presque aucun prise h la geo-
bert. metric,”—a majority of the candidates treated of the
methods of preventing the burning down of houses !
It is true, however, that on that occasion, Euler sent
a memoir which, though crowned, was unworthy of
his genius. Lambert in his “ Pyrometrie,” in 1779,1
had the rare merit of laying the foundations of the
science of conduction. He solved correctly this ques¬
tion :—“ If a thin conducting bar of indefinite length
be kept with one extremity heated to a constant degree
above the surrounding space, required the tempera¬
ture of any point in the axis of the bar 1” The solu¬
tion is, that the temperatures, or rather excesses of
temperature, diminish in a geometric ratio, at dis¬
tances reckoned in arithmetical progression, from the
origin of the heat.2 In this solution it is assumed,
(1.) That the flow of heat along the bar, is at any point
proportional to the rapidity with which the tempera¬
ture at that part of the bar is lessening as we recede
from the source ; in other words, that the flow of heat
from the hot part to the cold part, is more rapid in
proportion as the difference of temperature of two
sections of the bar at a given short interval is greater.
(2.) That the bar parts with its heat to the surround¬
ing space, exactly in proportion to its excess of tem¬
perature at evei’y part.
This beginning, which perhaps like many of Lam- (662.)
bert’s other writings was not very generally known, Biot,
had no sequel until 1804, when M. Biot attempted to
find the differential equation of the general movement
of heat on the same principles. But the form which
he obtained, including a mathematical solecism, be¬
trayed some error in stating the conditions. Three
years later Fourier had more success. But, conform¬
ably to the plan of this discourse, I shall premise
some facts regarding his early career, which was far
from commonplace.
Joseph Fourier was born in 1768, at Auxerre in (663.)
France. He was of humble parentage, and being Fourier—,
early left an orphan, was educated by the Benedic- J)!8 early
tine monks who, singularly enough, conducted with 15
success in that town a military school. It seemed
his fate to become either a priest or a soldier; yet he
was neither, though ere long familiar with camps.
He became first a pupil of the old normal school of
1 Pyrometrie, oder, von Maasse des Feuers und der Wdrme. Berlin, 4to, 1779. This work was posthumous, and contains many
riginal observations on Thermometry, Conduction, Solar Radiation, and Climate. a Pyrometrie, p. 184.
Chap. VI., § 6.]
HEAT—FOURIER.
947
Paris, when Lagrange, Laplace, and Bertliollet were
amongst the professors. He had already presented
to the Academy, at the age of 21, a paper on the nu¬
merical solution of equations, a subject of predilec¬
tion with him, and to which we shall presently return.
After leaving the Normal School, he was named one
of the original professors of the Polytechnic School,
a station of which he was justly proud, hut from
which he was withdrawn by the requisition to join,
along with Monge and other savans, the Expedition
to Egypt under Napoleon. It was the singular fancy
The Egyp- of that extraordinary man, to create an Egyptian
tian Insti- Institute, of a constitution similar to that of France,
tiite. Fourier was perpetual secretary. But it proved little
better than a waste of talent. The arts of Egypt were
not regenerated, and France was despoiled of some
of her ablest philosophers. Fourier had quite as much
to do with baLlcs and treaties as with equations and
experiments. Yet he often referred afterwards with
partial recollection to those stirring times, and re¬
counted, with the ardour of a somewhat garrulous
temper, the valiant feats of arms which he had wit¬
nessed. Fourier edited the account of the Expedition
to Egypt, and wrote the historical preface, the com¬
position of which ultimately prociAcd for him a seat
in the Academic Frangaisc.
(664.) On his return to Europe, he was appointed Prefect
Fourier 0f £}ie is£re in 1802, and Grenoble became his
correctly68 l10me ^or some years. Whilst he devoted a just
the anaiy- share of his attention to his public duties, he found
tical form time to produce his greatest work, The Analytical
blenTof™" Theory °f Heat. His first paper on this subject
conduction, dates from 1807. It was communicated to the Aca¬
demy of Sciences, but not printed. The subject was
however proposed for a prize, to be decided in 1812,
when Fourier’s essay was crowned, but, strange to
say, not published. The cause, it is to be feared, lay
in the jealousy of the greatest mathematicians of the
age. Laplace,Lagrange, and Legendre, the committee
of the Academy, whilst applauding the work, and ad¬
mitting the accuracy of the equations of the move¬
ment of heat thus for the first time discovered, insi¬
nuated doubts as to the methods of obtaining them,
and likewise as to the correctness of the integrations,
which were of a bold and highly original kind.
These disparaging hints were not supported by any
licat,ion—"precise allegations ; and we can scarcely blame Fou-
rivalry in rier for feeling indignant at the tyranny of the mathe-
the Insti- matiCal section, and little disposed to regard with
favour the few and comparatively insignificant efforts
of several of its members subsequently to ratify and
extend the discoveries which he had unquestionably
made. The manuscript, after lying for twelve years in
the archives of the Institute, where it was consulted
by different persons, was finally printed, word forward,
as it stood in 1812.1 Fourier’s long absence from
Paris in a remote provincial town, rendered this in¬
dignity possible at first; and afterwards, it was his
misfortune to be unable to hold a political station
without offence, amidst the violent intestine conflicts
with which France was afflicted. He alternately dis¬
pleased his old master Napoleon and the Bourbons,
and the consequence was, that after the Restoration
he found himself dispossessed of every employment,
master of not one thousand pounds, and refused by
the government even a seat at the Institute. This
indigence, so honourable to himself, and this neglect,
so disgraceful to others, tended, no doubt, to increase
an irritability, such as intense mental exertion often
produces, and which the injustice of his scientific
countrymen had already aggravated. Finally, how¬
ever, he received a modest post connected with the
civil administration of the department of the Seine;
he was also elected a member of the physical section
of the Academy of Sciences, and he finally became
perpetual secretary of that body.
Fourier’s papers on Heat show a remarkable com- (665.)
bination of mathematical skill with a strict and pre-^l8 Phy?‘‘
• • i i j • -r i • i cal Precl*
cise attention to physical considerations. In thishesi0n ex-
exccls almost every writer of his time, and especially periments.
his colleague and younger rival, Poisson. His expe¬
rimental skill is not to be so highly praised, although
he illustrated several of his solutions by actual trials,
which he submitted to calculation, and showed to
agree with theory. Their degree of precision, how¬
ever, hardly allows them to be considered as tests
of theory.
Fourier assumes the correctness of Newton’s law, ^66g ^
as well for communication of heat from point to point Assump-
of a solid, as for the external radiation by which Rtionsof the
parts with its heat into the surrounding space. InTheortlCal
the former case, the flow of heat is proportional to
the rapidity of the depression of temperatm’e, in the
direction in which the motion of the heat is considered;
in the latter, it varies as the excess of temperature
of the surface of the hot body above the surrounding
space, affected, of course, by a constant depending on
the radiating power of the surface. These, as I have
said, were also the Postulates of Lambert’s solution.
Fourier’s researches, fortunately perhaps, preceded
for the most part Dulong and Petit’s enquiry into the
true law of cooling. I say fortunately, since other-
wise Fourier might have been discouraged from at¬
tempting the solution of problems which are highly
important even in an approximate form.
With regard to the law of radiation, Fourier had ^ (667.)
the merit of showing, for the first time, the necessity of^thiTlaw
Leslie’s experimental law of the intensity of emanated 0f emana-
heat being proportional to the sine of the angle which tion.
the direction of emanation makes with the surface.
This he considered both mathematically and physi¬
cally. Mathematically, he showed that were this law
not true, a body might be maintained for an indefinite
time within an envelope of constant temperature, and
1 See Fourier’s note at the commencement of his paper, in Memoirs of the Institute for 1819 (printed 1824).
948
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(668.)
and of
“ exterior
conducti¬
vity.”
yet never acquire that temperature, even approxi¬
mately ; and physically, considering, that radiation
proceeds not from a mathematical surface, but from
a material physical stratum of an imaginable thick¬
ness, but which rapidly absorbs the emanations pro¬
ceeding from the inferior particles, he proved that
the attenuation due to oblique emanation will fol¬
low Leslie’s law, independent of the precise rate of
absorption in traversing the physical surface.
Fourier takes extraordinary pains to define and
Definition justify every step of his demonstrations. He has the
Lg power" great merit of having first given a clear definition of
conducting power, or conductivity proper, which is
this :—“ The number of units of heat (measured by
the weight of ice which it can melt) passing in unit
of time across a square unit of surface of an infinitely
extended plate bounded by two parallel surfaces at
unit of distance which are respectively maintained
at the freezing and boiling temperatures (unit of dif¬
ference of temperature).”1 In like manner, the “ ex¬
terior conductivity” expresses the number of units
of heat parted w ith by unit of surface to the air and
surrounding space, when the difference of their tem¬
perature amounts to unity.
(669.) Account of the Theorie Analytique de la Chaleur.
Fourier s —rpjie problems considered by Fourier in his Theorie
Theorie An- f . . ^
alytique de Analytique, reter principally to the propagation ot
laChaleur. heat in homogeneous conducting solids of definite
forms, and in some cases maintained in certain parts
at fixed temperatures.
(670.) The number of examples fully worked out is very
of problems smaH> but they may be referred to the following
solved by classes :—(1.) When some part of a solid has an inde-
him. finite source of heat applied to it, the remaining sur¬
face being exposed to the air, or having determinate
temperatures maintained at certain parts. In this
case, the state of the solid in regard to heat is per¬
manent, or independent of time; and the problem is to
assign the temperature of each part, and the flow of
heat through that part in a given direction. (2.) To
assign the temperature of every point of a solid pri¬
mitively heated, either uniformly or after any assigned
law, and at any given moment. (3.) To solve the
last question only in the case where the cooling at the
surface has been going on for an exceedingly long
time.
Stationar ^ c^ass Pr°hlems, the slender bar heated
condition^ ^7 a constant source of heat at one end, and exposed
of heat in a to the cooling influence of radiation and of the air,
which had been treated of by Lambert, is the simplest
and most important. The temperature of any thin
slender
bar.
slice perpendicular to the axis of the bar, is the
result on the one hand of the heat which it acquires
from the hotter slice nearest to it on the side of the
source of heat; and on the other, of the heat with
which it parts to the slice next beyond and also to
the air in contact with the exterior surface of the
slice and by radiation from the same surface. The
solution of this problem is that of a simple differential
equation of the second order, and the result is the
diminishing geometrical progression of temperature
already mentioned. This has been approximately con¬
firmed by some careful experiments of M. Biot, which
indeed are nearly the best which we yet possess on the
subject. But instead of drawing from them, as he
does, an argument for the accuracy of the Newtonian
law of cooling, the diminution of temperature along
the bar is far more rapid at first, and less afterwards
than that law indicates. In fact, the apparent agree¬
ment of the formula is owing to the use, in a case to
which it does not correctly apply, of that often mis¬
applied rule of the doctrine of chances—the method
of least squares.
The solution of another case of stationary temper- (672.)
ature,—an indefinite solid bounded by three infinite an iafi-
planes (two of which, B, C, are parallel, and the third, mte solld‘
A, perpendicular to both) having determinate tem¬
peratures,—requires the introduction of a species of
analysis, in which Fourier acquired great dexterity,
but which is of so subtle a kind as to have created
doubts in the minds of the committee of the Institute
to which the Memoir was referred, and to have been
a source of some controversy and much discussion
since. Fourier contrives to express, by an infinite
trigonometrical series, the law of temperature in such
a solid, which shall not only satisfy the differential
equation of the equilibrium of heat, but also the
conditions of temperature at the bounding planes, B
and C, which being zero by the problem, the value
of the temperature which, up to that point w?as finite,
suddenly comes to nothing, and has no value beyond.
This problem leads to a long digression on the pos¬
sibility of expressing by trigonometrical series, quan¬
tities which vary according to any conceivable law
and of determining the co-efficients of the successive
powers of the sines and cosines employed. The
theorem to which Fourier is led, in which any function
of x is expressed by a series of definite integrals, in¬
cluding sin x and cos x, is known by his name.
The problem, however, which Fourier most elabo- (673.)
rately treated, belongs to the 2d and 3d class,— Movement
namely, the cooling of a sphere primitively heated in a
Let F be the flux of heat measured as above, K the constant of interior conductivity, z an ordinate measured across the
thickness of the plate, and he temperature of the stratum of which ^ is the ordinate; then F= -K^; in the permanent
state the temperature varies uniformly from stratum to stratum. When the thickness and difference of temperature both are
equal to unity, K=F. The expression F= manifestly expresses the Newtonian Law, interpreted by Fourier as
stated above.
Chap. VI., § 6.] HEAT.—
in a given way, but so that points equi-distant from
the centre have a common temperature.1 It might
be expected that the symmetry of the conditions would
admit of a simple solution ; and such indeed was
sought by Professor Playfair long before, in a paper
in the Edinburgh Transactions, with reference to Geo¬
logical Speculations. It was, however, by no means
sufficiently general. It is shown by Fourier, that
even in the simplest supposable case—that where the
temperature of the sphere was originally uniform—
the resulting expression for the temperature of any
stratum at any time, though capable of algebraic ex¬
pression, cannot be assigned in finite terms, and no
attempt has been made to evaluate it generally. The
special cases which have been considered, are when
the sphere is extremely small, or has been cooling
for a very long time.
(674.) The extreme complication of even such apparently
Sources of sjmpie cases when solved in all their generality con-
tion in the sists in this, that the flow of heat across each part is
Problem of in fact dependent at each instant on the state of heat
the Sphere. jn eac]a other part, and this distribution of the whole
is equally unknown with the local distribution on
which the movement of heat in each part depends.
To this must be added the peculiarity of conditions
at the surface, where the temperature undergoes an
abrupt change. The law according to which the su¬
perficial particles radiate heat, is also different from
that according to which they receive it from the in¬
terior. When a body uniformly heated to a consider¬
able temperature cools in air, the subtraction of heat
from the surface commences with great rapidity, the
excess of temperature of the superficial particles being
very much greater than it ever can be afterwards.
The drain of heat from the interior of the sphere is
at first nearly imperceptible. The exterior cooling
will by and by become slower; and the degree in
which it takes place, will depend upon the rapidity
with which the conducting mass of the sphere is able
to supply fresh heat to the surface; then the rate of
superficial cooling will become relatively somewhat
accelerated, and a fresh drain will take place from
the interior towards the surface. It is only in the
case of exceedingly small bodies, or those of an in¬
finite degree of conductivity, that the body will cool
according to a simple law. In all other cases, there
will be characteristic periodical inflections in the
course of cooling. These, no doubt, are represented
in Fourier’s series, if it could be numerically calcu¬
lated ; and it is to be desired that some attempt were
made to represent it approximately. When the cool¬
ing has endured for a very long time, these gushes
of heat cease altogether; the surface has attained
nearly to the temperature of the surrounding space,
and the drain of heat from the interior is so slow,
-FOURIER. 949
that the progression of temperature is very gradually
and slowly disturbed.
Application to the Thermal condition of the Earth. (675.)
—This last case has been discussed by Fourier with Applica-
great address, relatively to the present condition of ^0(”e°frin_
the Earth, considered as a mass which has been once cipies to
at a high temperature, of which we have evidence the ther-
in the general increase of heat as we descend in mines, ™al condl
t •, , i a a • tion of the
or when we penetrate its crust by Artesian wells. Eartll
The surface of our planet receives a large amount of
heat annually by absorbing the sun’s rays, but parts
with it by radiation into free space, to an extent which
preserves a sensible uniformity of temperature from
age to age. The considerations connected with the
subject are these :—(1.) The proper heat of the earth,
and how much heat reaches the surface from the
(perhaps) still incandescent interior; (2.) How much
heat do we receive from the sun, what share of it
enters the surface, and how far, and according to
what periods does the influence of the seasons extend
below the surface ? (3.) What is the amount of refri¬
geration of the earth’s surface ?—how does the atmo¬
sphere affect it ? and, if the cooling be due entirely
to radiation, what are we to set down for the temper¬
ature of space, so as to account for the heat lost ?
First, As to the proper heat of the globe. Not to (676.)
go further back than the last century, the incandes-
cence of the earth’s nucleus was assumed as very pro- globe.
bable by Buffon and other popular writers, and their
opinions were, on the whole, confirmed by the pro¬
gress of observation. The existence of volcanoes was,
of course, an obvious argument; another was, that
if the earth were once hot it must be still cooling; con¬
sequently, climates are continually becoming colder,
especially in the Arctic regions, which it was supposed
depended most on the supply of heat from within. In
evidence of this change were quoted, not only the
remains of elephants found interred with flesh and
skin in the midst of Siberian ice, but also the un¬
equivocal proofs, so well known to geologists, that
at a period indefinitely more remote, tropical plants
of gigantic growth, and animals of a class which now
frequent only southern seas, appear to have lived
and flourished in high northern latitudes. But even
in the time of Buffon, attention was directed to a fact
yet more important for the theory of heat, namely,
the increase of temperature observed in deep mines.
Notwithstanding many sources of doubt and confu-manifested
sion, such as the heat from candles, and from men at the u'~
’ . f. i-ii • crease of
work in mines, from chemical changes in some cases, beat ;n
and from the increased density of the air, the fact of mines,
the increase is now well established, and also its
rate of progression with more certainty than in the
time of Fourier. On an average (including the best
data of all, those yielded by Artesian springs), the.
1 The problem of the Armil or ring, heated at one or several points, is one which offers considerable facilities for its solution,
but the results are of little utility, the form being so peculiar ; and even as a test of theory, the variations of temperature from
point to point are insufficient under the limited conditions in which the numerical solution is practicable.
950
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
increase appears to be l°Fabr., for 50 or 60 English
feet of descent. Fourier first undertook to enquire,
Whether, supposing the earth to have no primitive
internal heat, the continual action of the sun might
not produce the increasing temperature observed.
But he found, on the contrary, that there is no such
tendency, and that after a long time, the temperature
at any moderate depth below the surface (but be¬
yond the varying influence of the seasons) will be
constant. Now, observations on the temperature of
mines and Artesian springs extend to the depth of
1700 English feet, and the influence of the seasons
is usually quite extinct (in this latitude) at 50 or 60
feet. The nearly uniform increase beyond is there¬
fore due to a source of heat within, or, what amounts
to the same thing, to the relatively warmer state of
the nucleus. The analysis of Fourier shows, that
the variation of temperature in the successive strata
of a sphere, cooling with excessive slowness, is very
closely allied to the flux of heat which passes through
it, and which is spent by radiation or otherwise at the
Its insigni- surface. The result is exceedingly striking, and may
ficanteffectconsidered as remarkably well established; the
' flow of heat from the interior contributes to raise
the temperature of the surface by only one seven¬
teenth of a degree of Fahrenheit; or would melt an¬
nually a stratum of ice j^th inch in thickness. This
is all the refrigeration which the earth’s surface can
ever suffer on this account, and in its present state
of cooling, it would take millions of years even to
reduce it by one half. So little ground is there for
the belief of Buffbn and his friends, who imagined
that the destruction of animal and vegetable life must
rapidly ensue by reason of the diminishing central
heat.
D^;) Again, the depth to which we must descend in
thefluid or(^er reach a temperature sufficient for the supply
nucleus. of molten lava, is not excessive: for this depends
entirely on the conductivity of the earth’s crust,
which we know to be very small. A familiar in¬
stance occurs in streams of recent lava, where a crust
soon forms, on which a man may walk safely, yet
only be separated by a foot or less from the fiery
liquid. Fourier calculated that the temperatui’e of
incandescence may prevail at a depth within the
earth of only about 15 English miles, without affect¬
ing the superficial temperature by more than a small
fraction of a degree.
(678.) As it seems scarcely possible to ascribe some, at
secular ^east> °f the geological effects already mentioned to a
change of cause of which the variations are imperceptible in
climate. such vast periods, other writers have suggested dif¬
ferent possible explanations. One which appears to
have considerable probability, is that of Arago, that
the heat emitted by the sun has a secular rate of
change; in other words, that our sun is a variable star.
Secondly, As to the effects of the sun’s heat on (679.)
the earth. It has been already stated that Fourier Effect
showed that below a moderate depth, the heat of the helton the
earth would be uniform and invariable, so far as solar earth,
radiation is concerned. At smaller depths, it will
vary according to the season of the year, and these
variations will at all depths be gone through in the
same period with the variation at the surface, which,
is of course annual, but the inflections follow a pe¬
culiar law in each latitude and climate, and even in
one year compared with another. Within the depth
to which the influence of the seasons extends, the
amount of the range of temperature continually di¬
minishes, nearly in a geometrical progression, and at
length it becomes insensible. At increasing depths,
the periods of maxima and minima are continually
retarded, so that at a certain depth, the earth is hot¬
test in winter and coldest in summer. A smaller
fluctuation of the same kind, and penetrating to a
smaller depth, follows the diurnal range of tempe¬
rature. The manner in which these interesting phe¬
nomena are connected with the conducting power and
specific heat of the earth’s crust, was clearly pointed
out by Fourier.
Before as well as after these theoretical invest!- ^680 ^
gations, observations on thermometers sunk to dif- Theory
ferent depths in the ground had been made, and the compared
results confirm these conclusions of theory in eveiT
respect. Such observations were made by De Saus-
sure, Leslie, Arago, Quetelet, and other experimen¬
ters, including the writer of these pages, who caused
careful experiments to be made for five years, on
three sets of thermometers, placed in different kinds
of soil and rock, extending to a depth of above 25
feet. By means of these, the conductivity of those
various soils was determined with accuracy, and data
afforded for subsequent enquiry.1
Amongst the most interesting enquiries connected (681.)
with this subject, is the total quantity of heat re- Total quan-
ceived in a year from the sun by the absorptive tlty ?f *“,at
FGCeiVGQ bv
action of the earth’s surface; but this does not ap- the 1
pear as yet to have been successfully answered, from the
Nevertheless, M. Pouillet, from merely experimen-sun-
tal data, considers that he has proved that the
amount of solar radiation which reaches the earth
would melt in a year an average thickness of 31
metres of ice, all over its surface, provided that it
were entirely absorbed. Poisson has obtained a re¬
sult four times less, and estimates the effect of the
sun in raising the temperature of the climate of Paris
at 24 centigrade degrees, a result incredibly small.
Thirdly, On the temperature of space. Fourier .rR9,
was probably the first who introduced this idea into The tem-
science. The term perhaps is a doubtful one and perature of
liable to misconception, but the object of the enquiry sPace—
admits of being precisely stated. The researches of
^ransacl*ons Royal Society of Edinburgh, vol. xvi., where a history is given of the observations previously
Chap. VI., § 6.]
HEAT.—FOURIER—POISSON.
951
Dulong and Petit1 upon the cooling of a body by
radiation only within an envelope having a tem¬
perature lower than itself, include, as a particular
case, that in which the body receives nothing from
the envelope,—when the radiation is entirely that
of loss without any gain; and yet the cooling pro¬
ceeds with a finite velocity. It could not with any
propriety be said in such a case, that the tempera¬
ture of the space in which the body cools is in¬
finitely low; it cannot be said to have any tempera¬
ture at all.
(683.) Now, in the case of our globe and its atmosphere,
defined by We have a heated mass, suspended as it were, in space.
Fourier. jp f.jiere were no other bodies in the universe, the earth
must by degrees lose its heat. We know indeed that
it is cooling. The pi’oportion of its native heat an¬
nually emitted, would melt a crust of ice ^th inch
thick. This heat is dissipated in space. It may
therefore be enquired, whether a sphere of known
conducting power and of known temperature at the
surface, is parting with its heat to space at a rate
which supposes it to radiate without any requital, or
whether it receives from space (or the bodies which
space contains, independently of the sun) any portion
of the heat which it thus dissipates. To solve this
question, we must evidently know with great accu¬
racy the radiating power of the surface of the earth,
than which, unfortunately, no datum is more com¬
pletely uncertain: and the influence of the atmo¬
sphere (which is truly a part of the earth) renders the
solution still more indeterminate. It is not known
what method Fourier took to arrive at a numerical
result, but it is wTell known that he obtained it in a
way which appeared satisfactory to himself, and that
he often referred to it. He supposed the “ temper¬
ature of space” to be 50° or 60° below zero on the
centigrade scale, and believed he did not err in fixing
it by more than 8° or 10°. By this we understand,
that after infinite ages, the earth, or any other body
placed in the same situation and previously heated,
would attain this temperature and no lower.
(684) slight sketch gives an imperfect idea of the
extent and originality of Fourier’s labours. But
enough has been said to show, that he must rank
amongst the most considerable philosophers of his
day. That he excited the jealousy of the great ma¬
thematical geniuses of the previous generation, and
that his new train of research, though fully accepted
by those who succeeded him, has as yet received but
slight extension at their hands, are facts which con¬
cur to prove his originality and merit. That he
did not solve more cases of the propagation of heat,
and that some of his solutions are so complicated
as hardly to be such in a practical sense, show only
the extreme difficulties of a subject which touches
every where the boundaries of existing mathematical
knowledge. In the opinion of many persons, it is to
be desired that some at least of the problems of con¬
duction wrere treated in a somewhat different way,
and approximations obtained by the application of a
less abstruse calculus. But towards this desirable
result, little has yet been done.
As a pure mathematician, Fourier occupies a (685.)
distinguished rank. His conversion of functions of''“tin^s
, . , . . ,, . , ... , . of Fourier
every kind into series of periodical quantities—hison pUre
treatment of problems, involving discontinuous laws mathema-
—his solution of higher differential equations—are tlcs-
all important additions to analysis,to the improvement
of which, as he has himself very justly observed,
physical problems are ever the most important ave¬
nues. Such considerations as Fourier treated of
could hardly have entered into the mind of a mathe¬
matician not guided by a specific physical enquiry.
His favourite subject of the solution of Numerical
Equations, which brought forth his first essay—which
occupied him even on the banks of the Nile—and an
elaborate work on which was almost his last addition
to science,—is of course one of less general interest.
His experimental abilities, as we have said, were (686.)
not equal to his mathematical; and it is to be re-ExPeri‘
gretted that his schemes for several practical appli-
cations of theory seem to have been left imperfect.
He invented a Thermometer of Contact, an instrument
for determining the conductivity of bodies, which is
but little known or used, and of which the theory
was left incomplete. He also joined Oersted in ex¬
periments on Thermo-Electricity. He studied with
great care the principles on which his theories were
based, and seems throughout to have desired to leave
no doubtful step in his reasonings, nor to make any
tacit or unproved assumptions. His compositions
are minutely clear. To them we might apply the re¬
mark attributed to Voltaire—“Whatever is obscure
is not French.” If there be obscurity, it is only due
to the abstruseness of the subject, not to the manner
of conveying it.
Fourier succeeded Delambre as Secretary of the Ma- (687.)
thematical Class of the French Academy of Sciences,His death,
and w7rote several Eloges. He died no the 16th May
1830, generally respected.
We will here, in a few words, comment on the (688.)
subsequent progress of the subiect of the Conduction Fourier 8
„ tT , 1 ° successors,
ot Heat.
Whilst Fourier’s papers were still in the archives (689.)
of the Institute, they were consulted by Poisson, who Poisson‘
published solutions of several problems based on
Fourier’s principles, and coinciding in result with his.
As the analysis used was somewhat different, the
coincidence in so new a subject was not without im¬
portance. In 1835, the Theory of Heat of the same
author appeared, based on the law of cooling, dis¬
covered by Dulong and Petit, which Poisson, with
1 See the next Section.
952
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
■unaccountable yet characteristic rashness, chose to
consider as applicable to the communication of heat
from particle to particle, as well as to its dissipa¬
tion from the surfaces of bodies. But the result was
worthy of the looseness of the assumptions; the terms
arising from the peculiarity of Dulong s law are
mostly dispensed with as the investigation proceeds ;
and the whole work is to be regarded rather as a
mathematical exercitation, than as a serious step in
physics. Having elsewhere recorded a criticism on
that part of Poisson’s work which treats of the Heat
of the Globe, I shall not dwell farther on its defects.1
(690.) Professor Kelland has published a work2—the only
Kelland’s one inteil<le<^ ^or students—on this subject, and he has
Theory of likewise made a valuable report to the British Asso-
Heat. elation, on the best means of comparing the Mathe¬
matical Theory of Heat with Observation.3 He has
suggested, that the results of the Newtonian law of
cooling may be used in combination with such an
hypothesis as to the relation between quantities nf
heat and the temperature shown by an air thermo¬
meter, as will reconcile it with Dulong’s law. But
there is reason to think, that internal conductivity
varies with temperature in the reverse manner of ex¬
ternal cooling ; in other words, that it diminishes as
the absolute temperature increases.4
MM. Duhamel and Stokes have considered the (691.)
propagation of heat in bodies which do not conduct it Casf of
uniformly in all directions ; and their investigations do
are very interesting in connexion with the beautiful notconduct
observation of M. de Senarmont, that such is the case heat uni¬
in crystallized bodies. It is easily shown in a plate in
of gypsum coated with a thin layer of wax, to a small tions.
part of which heat is applied.
§ 7. Dulong.—The Law of Cooling.—Progress of the Science of Radiant Heat between Leslie's
and Melloni's Discoveries ; transmission of Radiant Heat through Glass. Herschel; De la
Roche ; Professor Powell.—Theory of Dew ; Wells.
(692.) The researches of Leslie on Radiant Heat, though
Subject of very generally appreciated both at home and abroad,
heatr^ vvere not’ on publication, immediately repeated
sumed. or extended. On some points they were seriously
controverted. But the labours of most of his imme¬
diate contemporaries, of whose names we have given
a few at the head of this section, were rather prepa¬
ratory to the fuller developments of a later time—to
be made with improved apparatus—than demon¬
strated discoveries. I make an exception, however,
with regard to the experiments of Dulong and Petit
on the laws of simple radiation and of the cooling
of bodies by the contact of gases, not only because
they established propositions quite new in an incon¬
trovertible manner, but also because they introduced
into this branch of science a mode of investigation so
delicate and precise, and methods of reduction and
of physical analysis so beautiful and convincing, as
placed the whole science of Pleat on a new footing.
The main credit is due, we believe, to Dulong, who
was one of the most estimable and accomplished phi¬
losophers of his time.
(693.) Pierre Louis Dulong was born in 1785, and
arTeminent s^owe<i precocious talents. He w-as admitted to the
chemist. Polytechnic School at the age of 16, and rose through
every grade of that celebrated institution until he
became “ Directeur des Etudes.” It is superfluous
to say that he was a good mathematician. He was
also a most excellent chemist; and the honour of
being discoverer of the most terrific of fulminating
compounds (chloruret of azote) was purchased by the
loss of one of his eyes. But his experiments on
Heat are those by which he will be longest remem¬
bered. The most important series of these was de¬
voted to a rigid examination of the amount of heat
radiated under different circumstances, and of that
dissipated by the contact of air.
Thelawof Cooling.—It had beensuggested byNew- (694.)
ton, and tacitly admitted by nearly all writers on heat, Dulong
includino; the most eminent, that simple radiation (or and Petl?
pulsation, in the language of Leslie) takes place in di- Newtonian
rect proportion to the excess of temperature of the hot law of
body above the surrounding space. Martine, and par- cooling*
ticularly De la Roche, had indeed thrown doubt on
the subject, and had rendered it probable that at high
temperatures the velocity of cooling (which is propor¬
tional to the radiant energy) is considerably greater
than Newton’s law supposes. Dulong and Petit,
however, first demonstrated this. They disengaged
the experiment as far as possible from the influence
of the contact of air, by using the most perfect ex¬
haustion which the best air-pumps could produce;
and it appeared very plainly from the result of ob¬
servations made under successive degrees of rarefac¬
tion, that instead of there being the slightest appear¬
ance of radiation ceasing to take place when the vehicle
1 See Second Report on Meteorology, Brit. Assoc. Reports, 1840.
2 Theory of Heat. Camb., 1837. 3 ^rit. Assoc. Reports, 1841.
4 This at least is the result of an experimental investigation by myself on the conductivity of iron, executed on a principle
which I believe to be new, but which I have not yet been able to publish. Mr Airy and Professor Kelland are each in possession
of the outline of my method ; and the result noted in the text was briefly announced by me in the Reports of the British Association
for 1852. If my health permits, I shall resume and publish these experiments. I may here add, that I pointed out in 1833,
from some experiments which I made at that time {Proceedings of the Royal Society of Edinburgh, vol. i. p. 5), that the metals
range in the same order as conductors of Heat and of Electricity ; and this law appears to be confirmed by more recent obser¬
vations.
Chap. VL, § 7.]
HEAT.—DULONG AND PETIT.
953
of air was absent, the influence of the latter became
less and less perceptible.
(695.) The principal apparatus of Dulong consisted of a
Their ap- balloon of thin copper about a foot in diameter, coated
paratus. internally with lamp black, and placed in connection
with an air-pump, so that any portion of atmospheric
air could be extracted up to about f of the whole,
and any other gas could be introduced into it. The
temperature of the balloon could be nicely regulated by
introducing it entirely into a water trough. Into the
centre of the balloon, thermometers of different sizes,
or having different kinds of surface, could be intro¬
duced. The temperature of the balloon having been
first regulated, the thermometer under experiment
(being itself the radiating and cooling body) was
heated nearly to the boiling point of mercury, and
inserted in the balloon so as to occupy the centre of
it. The exhaustion and other arrangements being
made, the observations on the rate of cooling of the
thermometer commenced when its temperature was
as high as 250° or 300° centigrade, equivalent to 482°
and 572° Fahrenheit.
(696.) With respect to simple radiation, or when the
outling^not e^ect a'r t^ie balloon is estimated as nothing,
simply as the inaccuracy of the Newtonian law was soon ap-
the excess parent. Whilst the excess of temperature of the
of heat. cooling body above the envelope or balloon remained
constant, and the absolute temperature of both was
made to vary, the velocity of cooling, instead of
being constant, increased rapidly with the tempera¬
ture. Thus the excess of temperature being in every
case 200° centigrade, and the temperature of the
balloon being ... 0°, 20°, 40°, 60°, 80°,
the rate of cooling was 7*4, 8-6, 100, 11-6, 13-4.
The whole of an elaborate series of observations was
beautifully and satisfactorily represented by a for¬
mula admitting of this simple physical interpre¬
tation, viz., that the cooling of the thermometer is
the difference between the heat which it parts with to
the envelope and the heat which it receives from the
envelope; and that the heat thus parted with, either
by the thermometer or the envelope, varies in a geo¬
metric ratio with its temperature.1
(697.) The effect of contact of a gas in cooling the ther-
mometer is more complex. It is independent of the
air on the texture of the surface, as Leslie had already supposed,
rate of The cooling power of a gas is proportional to a cer^
cooling. tain power of its elasticity, which varies for each; it
takes place more rapidly in hydrogen than in any
other known gas, which was likewise discovered by
Leslie. It also comes out rigorously, that the ratio
of the radiating power of different surfaces is the same
at all temperatures. This ratio for glass and silver
is 5*707 : 1. Assuming this last principle, and also
that the cooling due to the contact of air is indepen¬
dent of the surface, the law of cooling in vacuo may
be deduced from the observed cooling of two thermo¬
meters suspended in air, and having glass and sil¬
vered surfaces respectively. Dulong and Petit found
that, when they analyzed their experiments in this
way, they obtained values for the radiation in vacuo
almost absolutely coinciding with what direct experi¬
ment had already given. No more perfect criterion
could be desired of the soundness of every link of the
chain of experiment and induction.
We shall not analyze Dulong’s other memoirs. (698.)
They regarded matters in the science of Heat requir- ®ther ™e‘
^ ° ... . ■L . moirs of
ing the same skill in devising apparatus and in mani- j)uiong on
pulation, the same caution in eluding errors, and the the laws
same just principles of calculation as in the invest!-of beat-
gations already specified. They did not, however,
lead to the discovery of laws so striking and so ge¬
neral. They included the very delicate and difficult
subject of the laws of the thermal expansion of
bodies, particularly that of air and of mercury, which
were applied to the theory of the thermometer, the
very basis of all exact knowledge in the doctrine of
heat. Another referred to the specific heat of the Specific
gases, an enquiry of the very greatest difficulty, in heat of
which we still find physicists disagreed. Dulonggdbes'
bethought himself of using Laplace’s celebrated cor¬
rection for the velocity of sound due to the heat de¬
veloped during the compression of an elastic medium
(art. 433), and proposed to deduce the heat thus
developed, by a comparison of the observed and theo¬
retical (Newtonian) velocity of sound, and thence to
obtain the specific heat. The theoretical velocity is
easily obtained from the density of a gas under a
given pressure: the observed velocity was ingeni¬
ously found by sounding one and the same organ
pipe with the different gases in succession, and ascer¬
taining the pitch by the aid of Cagniard de Latour’s
Sirene. (441.)
One of Dulong’s latest, most elaborate, and most (699.)
useful labours, was ascertaining the elasticity of high- ^a8'
pressui’e steam in terms of its temperature. These steam.
experiments were carried as far as 24 atmospheres
of pressure. In the course of them the law of Ma-
riotte and Boyle was verified up to the same limit.
The condensation of air was found to be exactly pro¬
portional to the pressure. We shall return to the
subject of these later experiments of Dulong in men¬
tioning the still more recent ones of M. Begnault.
Dulong was unfoi'tunately lost to the world at the (700.)
comparatively early age of 54. His was the peculiar Character
merit of a well-balanced scientific mind. He felt0 u ons‘
1 Thus symbolically expressed:—-
V ~ m
(a*** - «*);
where V is the “ velocity of cooling,’’ or depression of the thermometer in centigrade degrees in one minute, supposing it to con¬
tinue constant for so long; 0 is the temperature of the envelope; t + that of the thermometer; a is a constant independent of
the size and surface of the cooling body, and which is = 1'0077 ; m is a constant depending on the dimensions and surface of
the body.
YOL. I. 6 E
954
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
the necessity of introducing into physics a degree of
precision then almost unthought of. Coulomb had
done something of the kind in other branches ; but
in Heat it was really new. It was speedily succeeded
by a rapid advance of precision in almost every kind
of delicate experimental research. Nowhere can
the student of physics find a better model than in
the celebrated memoir on the Law of Cooling, which,
we may add, received, as a matter of course, from
the Academy of Sciences, the prize in competition
for which it had been composed.1 It is only justice
to the countrymen of Dulong to say that they retain
the superiority in the deduction of numerical laws
from observation, which Coulomb and he conspicu¬
ously exemplified. The industry of the Germans and
of the English have indeed been great; but in this
particular enquiry they have not equalled in address
the members of the French Academy.
(701.)
(702.)
Observa¬
tions of Sir
W. Her-
schel on
the heat of
the solar
spectrum.
(703.)
Other ex¬
periments.
In order to complete our sketch of the more im¬
portant steps connecting the discoveries of Leslie with
those of Melloni, we will now, going back a little in
point of date, trace the origin of correct experiments
on the immediate transmission and refraction of heat
by solid substances.
Sir William Herschel having found it requisite in
the course of his arduous observations on the sun to
devisemeans for preventing the intense heat of its rays
from reaching the eye, was naturally led to observe the
effectof different coloured glasses, and even of coloured
liquids in this respect. He also placed thermometers
in different parts of the spectrum formed by a prism,
in order to discover which of the rays it was most
important to exclude. The singular result at which
he arrived was this, that the intensity of heat accom¬
panying the light of the sun not only increases from
the violet to the red end of the spectrum (as was
already known), but is more intense quite beyond
the red, and gradually diminishes in force for a long
way farther. This result was keenly contested by Les¬
lie, butwas confirmed by Englefield and Davy. Berard
admitted the existence of invisible heating rays from
the sun, but yet found the maximum effect within
the red. Seebeck, by numerous experiments, proved
that the position of the maximum depended on the
nature of the prism/being found even in the yellow
ray when a prism of water is employed, whilst with
flint glass it always occurs in the space beyond the
red. The rationale of this curious result was first
discovered by Melloni, whose labours will be detailed
in another section; and it was shown to depend on
the different degree of absorption exercised on the heat
of the several rays of the spectrum by the differing
material of the prisms.
Herschel made a very great number of experiments
on the transmission both of solar and fire-heat through
different kinds of glass and other bodies. But they
were rough trials, giving a sort of practical test of
this quality, rather than admitting of accurate esti¬
mations of the quantities of transmitted heat. It
was impossible, for instance, to infer from them the
degree in which the warmth induced in the glass or
other medium by the heat which it absorbed, tended
to raise the indications of the thermometer beyond;
although such an effect was manifest from the re¬
sults of the experiments themselves. Hence it was
open to an objector to deny the direct transmission
of radiant heat through such bodies as glass, except
in the cases of the sun and of brilliant combustion,
when it cannot be doubted.
Prevost had proved to his own satisfaction the (704.)
immediate transmission of heat derived from bodies Important
even when below the temperature of visible redness, exPeri'
' in Grits of
by using thin screens of glass, and renewing them De ia
frequently before they could have absorbed much Roche on
heat. Maycock obtained a similar result; but to th.e t.rans'
De la Roche is due not only the establishment of°
this fact beyond any reasonable doubt, but also the heat
discovery of certain laws of its operation which are through
inexplicable on any other supposition but that ofglass'
immediate transmission. One of these laws, for in¬
stance, was this, that when a series of thin glasses
are interposed between a source of heat and a ther¬
mometer, each successive glass transmits a larger pro¬
portion than the previous ones of the heat which falls
upon it. De la Roche rightly accounted for this sig¬
nificant fact by assuming that heat is not homoge¬
neous, and that the heat which has once passed
through glass has lost the rays which glass most
easily intercepts. He farther found that the sus¬
ceptibility of heat to pass through glass increases
rapidly with the temperature of its source. The
experiments of De la Roche date from 1812.
The next step was made by Professor Powell of (705.)
Oxford (1825). He showed that the quality of the Professor
heat transmitted by glass is not the same as thatPowe11-
of the incident heat. This he proved by ascertaining
the proportion of heat absorbed by a black relatively
to a ivhite surface. This proportion was invariably
increased by the interposition of glass. Mr Powell
concludes that heat consists of two kinds intimately
mixed. That of which the absorption depends on the
colour of the surface on which it falls, is usually
luminous, and is most easily transmitted by glass.
That kind of heat which is equally absorbed by black
and white surfaces is totally devoid of light, and is
sometimes considered as pure radiant heat.
It will be sufficient here to refer to an interesting (706.)
Essay on Dew, published by Dr Wells in 1815, in Wells>
which he applies Leslie’s experiments on the radiating 0
As the original paper of Dulong and Petit, in the Memoirs of the Institute, or the Annales de Chimie, is not always acces¬
sible, I may mention that it is translated almost or quite in extenso in Thomson’s Annals of Philosophy, vol. xiii,, and in
Mr Lunn’s excellent treatise on Heat in the Encyclopaedia Metropolitana.
Chap. VI., § 8.]
HEAT.—MELLON!.
955
(707.)
Recent ob¬
servations
on radiant
heat.
(708.)
Melloni—
the asso¬
ciate of No-
bili.
(709.)
The ther¬
mo-multi¬
plier, an
instrument
of research.
(710.)
power of different surfaces to account for the appa¬
rently capricious formation of dew in different situ¬
ations,—establishing that it is moisture deposited
from the lowest stratum of air upon surfaces cooled
below the “ dew-point,” by their unrequited radiation
of heat towards a clear sky. A slight wind, by con¬
tinually restoring the equilibrium of temperature to
the surface, prevents the deposition.
§ 8. Melloni.—Recent History of Radiant Heat—Transmission and Refraction of Heat; Pro¬
perties of Heat analogous to Colour.—Experiments in Great Britain on the Polarization
and Double Refraction of Heat.
The length to which this chapter has already ex¬
tended, must be my apology for bringing concisely to a
conclusion what remains to be stated regarding the
progress of the subject of radiant heat. With the ex¬
ception of the excellent researches of De la Roche on
the immediate transmission of radiant heat through
glass (mentioned in the preceding Section), but which
that ingenious philosopher did not live to extend
and complete, little of importance was done between
the researches of Leslie and those of Melloni, of
■which we are now to speak.
Macedonio Melloni, a native of Parma in Italy,
became associated as an experimenter, probably about
the year 1828 or 1829, with Nobili, a skilful and
ingenious physicist of Reggio (Modena). Nobili
was well known by his experiments on galvanic Elec¬
tricity and on Electro-Magnetism. He wras also the
great improver of Schweigger’s Multiplier, rendering
it an instrument of precision ; and to him we owe the
happy and ingenious application of Thermo-Electri¬
city to the measurement of minute effects of heat.
The Thermo-Multiplier, a thermometer of extreme
delicacy, though improved by Melloni, was (as has just
been stated) the invention of Nobili. It consists of
two portions, a sentient part and an indicating part.
The first is composed of a number of short thin bars of
antimony and bismuth, arranged like a square faggot,
pairs of bars being soldered together in consecutive
order at the opposite ends of the faggot, so as to form
a single bent metallic conductor. If the junctions
exposed at one end of the faggot are subjected to
heat, and those at the other end kept cool, the effect
will be a thermo-electric current of considerable in¬
tensity generated by the pile. This current is con¬
veyed by means of two wires from the opposite ends
of the system, which are connected with a delicate
galvanometer which forms the indicating part of the
apparatus. In practice, one end of the pile, armed
with a conical reflector for concentrating the rays of
heat, is exposed to a calorific source whose radiant
effect is to be measured, whilst the other end is care¬
fully screened from external influences. The devia¬
tions of the galvanometer needle indicate the heating
effect as on the scale of a thermometer. The pre¬
cautions required in the construction and use of the
instrument, and in the interpretation of its results,
are too numerous to be mentioned here.
Nobili, in conjunction with Melloni, applied the
thermo-multiplier (amongst other experiments) to
the proof of the instantaneous transmission of heat
through glass and other solid and liquid bodies.
From 1831, this enquiry was conducted nearly (711.)
exclusively by Melloni, who about that time settled Melloni
first in Geneva and then in Paris, having been com- (llseoveis
pelled, on political grounds, to quit Italy. His first derful
and most important original memoir was presented trans-
to the Academy of Sciences early in 1833, and was rodTsaU^
received with marked coldness, if not incredulity, by for heat,
that body. A few months later, the writer of these
pages had an opportunity of seeing Melloni’s ex¬
periments in Paris, and he made known their im¬
portance at the immediately succeeding meeting of
the British Association at Cambridge. The Royal
Society of London in no long time awarded their
Rumford medal to Melloni, after which mark of
foreign approbation, he first obtained a hearing
from the Institute of France. The most consider¬
able result at which he had then arrived was this :
that rock-salt possesses a power unapproached by
any other substance of transmitting heat of any
temperature and from whatever source, with ex¬
tremely little loss ; and as a natural consequence of
this, that heat wholly devoid of luminosity, such as
that from boiling water, or even the heat of the hand,
may be refracted by prisms and lenses of rock-salt
exactly in the same manner as light is refracted by
glass. The reality of these effects (which had excited
the persevering scepticism of the Parisian Savons')
was demonstrated by a great number of most inge¬
nious experiments, in which every possible source of
error and confusion was avoided or allowed for.
Melloni even believed that the loss observed in (712.)
passing heat of any temperature, high or low, through
polished screens of rock-salt, was precisely the same;
and, moreover, that it occurred entirely at the two
surfaces by partial reflection, so that the solid me¬
dium was absolutely transparent for every kind of
heat. It is certain that the loss is in every case
small; but this almost paradoxical conclusion has
not been completely confirmed by those who have
repeated his experiments. The important and un¬
expected discovery of the nearly complete trans¬
parency of rock-salt for heat, enables us to construct
complex thermotic apparatus for refracting and con¬
centrating it, analogous to those of glass which are
used in optics.
The next point clearly made out by Melloni, was (713.)
the specific action of different bodies in sifting the
956
MATHEMATICAL AND PHYSICAL SCIENCE.
[Drss. VI.
The specific rays of heat they transmit, stopping altogether certain
action of kjn<is or qualities of heat and transmitting others,
substances Substances, in general, transmit most readily the heat
on the rays radiated by surfaces having a high temperature; this
of heat.— already been shown to be true in the case of glass
of heat1011 h? L)e la Roche. That experimenter had also demon-
6at' strated fas we have seen in Art. 704) that successive
plates of glass intercept a constantly decreasing per¬
centage of the heat incident upon them. This may
be explained by supposing radiant heat to be, like
the light of the sun or of a flame, heterogeneous,
containing rays of different qualities, some of which
are easily transmitted and others are wholly stopped
by glass. And if we pursue the analogy with re¬
spect to other substances, we may imagine (for the
sake of illustration) heat to be coloured, and that
different media, though equally transparent and co¬
lourless as regards light—such as glass, rock-crystal,
and ice—exercise a specific action on the rays of heat,
each transmitting certain portions of the heat and
stopping others. Rock-salt alone (according to Mel-
loni) is absolutely coZoarZess with respect to heat, trans¬
mitting all its varieties with uniform facility. Thus
equally thick and equally clear plates of salt, glass,
and alum, transmit, out of 100 rays of heat from
different sources the following proportions :—
Heat from
a bright
flame.
Rock-salt 92
Plate-glass  39
Alum   9
Heat from
incandes¬
cent Pla¬
tinum.
92
24
?
Heat from
a surface
at 700°
JFahr.
92
6
0
Heat at
212°
92
0
0
(714.) Let, however, heat which has been sifted by a plate
Refrangi- 0f alum fall on another similar plate, then instead of
Heaif 9 per cent., 90 per cent, will be transmitted. On the
other hand, if we unite two plates of opposite trans¬
missive qualities, as alum and green glass, the com¬
bination is almost absolutely opake, just as a combi¬
nation of two coloured glasses giving different pure
tints (say red and green) would be opake for light.
The working out of this beautiful enquiry is entirely
due to Melloni; and he has published a separate work
on the “ Coloration of Heat.”1 He also rendered it
probable that the rays most easily absorbed by glass
and bodies generally are the least refrangible; and this
has been made certain by direct experiments by the
author of this Dissertation, who, by a peculiar me¬
thod, founded on the Total Reflection of heat within
a prism of rock-salt, has obtained the following In¬
dices of Refraction:—
(715.)
Explana¬
tion of
point of
maximum
heat in the
Heat from a lamp, mean refractive index 1-531
Do. passed through glass 1-547
Do. do. alum     ,.1-558
Mean luminous ray 1562
Melloni ingeniously applied the facts previously
mentioned to explain the variable position of the
hottest part of the spectrum, as observed by Sir
spectrum. i j^a Thermochrose, ou la Coloration Calorifique. Naples, 1850.
2 Memoires dSArceuil, vol. iii., p. 5.
William Herschel and others. It depends on the
nature of the prism employed. In a prism of rock-
salt, the hottest part of the spectrum is as far beyond
the extreme visible red, as the interval between that
red and the yellow ray in an opposite direction.
Through the intervention of Arago and of Baron (716-)
Humboldt, Melloni ultimately obtained permission to
return to Italy and to reside at Naples, where he spent
his latter years. He ceased, however, to prosecute
his researches on radiant heat with the same energy,
under circumstances of ease and comparative affluence,
that he had done in the period of distress and obscu¬
rity. Nevertheless, several original papers were writ¬
ten by him at this period, as well as the condensed
account of his earlier researches on the Coloration of
Heat, of which only the first volume appeared. Mel¬
loni died of cholera at Portici, in August 1854,
aged 53.
The analogy of Radiant Heat to light, strikingly (717.)
established by Melloni, with respect to the diversified
refrangibility and other qualities of the various radi- polarize ra-
ations emitted by one or different sources, suggests diant heat
an enquiry as to the intimate nature of these two Gerard,
agencies. No answer is likely to be so conclusive
as an appeal to the test of Polarization, which, in
the case of light, has been so remarkably explained
by the theory of the transverse undulations of a me¬
dium. Some years before any of Melloni’s papers
appeared,—indeed, before he had entered on the in¬
vestigation just noticed,—the writer of the present
Dissertation had attempted, by means of common
thermometers, to test the polarizability of heat. The
trial was not a new one ; but, except in the case of
the heat of the solar rays, the results seemed to be
inconclusive, or were even wholly negative. Berard
had, indeed, not long after the discovery by Malus of
luminous polarization by reflection, repeated (in 1812)
that experiment with sun-heat, and also with the
heat emanating from terrestrial sources ; and as he
believed with success.2 I have ventured to call his
experiments inconclusive, because others besides my¬
self vainly endeavoured to repeat them. Professor
Powell failed with ordinary thermometers, and at a
later period Nobili announced a decidedly negative
result, obtained with the thermo-multiplier. Simple
radiant heat, he affirmed, is not polarizable by re¬
flection.3
I have just referred to my own early experiments (718.)
on the subject (which were likewise inconclusive), Experi-
in order to explain that it was natural, on hear- ^g^esent
ing of the application of the thermo-multiplier writer,
to measure radiant heat, that I should wish to
repeat them with the new instrument. This I
did in 1834. I first succeeded in proving the
polarization of heat by tourmaline (which Mel-
3
Bibliotheque Universelle, Sept. 1834.
Chap. VI., § 9.]
HEAT.—M. REGNAULT.
957
Depolari¬
zation of
heat.
(719.)
M. Reg-
nault.
(720.)
Skill of
French ex
perimen-
ters.
(721.)
Co-ef¬
ficients of
expansion
of gases.
loni had announced did not take place) ;x next, by
transmission through a bundle of very thin mica
plates, inclined to the transmitted ray ; and after¬
wards by reflection from the multiplied surfaces of a
pile of thin mica plates placed at the polarizing angle.2
I next succeeded in showing that polarized heat is
subject to the same modifications which doubly re¬
fracting crystallized bodies impress upon light, by
suffering a beam of heat (even when quite obscure),
after being polarized by transmission, to pass through
a depolarizing plate of mica, the heat traversing a
second mica bundle before it -was received on the
pile. As the plate of mica used for depolarization
was made to rotate in its own plane, the amount of
heat shown by the galvanometer was found to fluc¬
tuate just as the amount of light received by the eye
under similar circumstances would have done. This
experiment which, with the others just mentioned,
was soon repeated and confirmed by other observers,
still remains the only one proving the double refrac¬
tion of heat unaccompanied by light; and though
somewhat indirect, it will hardly be regarded by
competent judges as otherwise than conclusive. Ice¬
land spar and other doubly-refracting substances,
absorb invisible heat too rapidly to be used for effect¬
ing directly the separation of the rays, which requires
a very considerable thickness of the crystal. I also
succeeded in repeating FresneTs experiment of pro- Circular,
ducing circular polarization by two internal reflec- polariza¬
tions. The substance used was of course rock-salt.3 tlon'
§ 9. M. Regnault.—Numerical Laws of Expansion by Heat; Rudberg.—Vaporization;
Dulong.—Latent Heat; Ilygeometry.
The limits of this Essay will not permit me to do
more than allude in very general terms to the merito¬
rious services of M. Henri-Victor Regnault in the
science of heat. In the seventh section of this chapter
I have mentioned his name in connection with that
of Dulong, whose researches he has prosecuted, and
whose position in the College de France he now fills.
The attention of M. Regnault has been devoted
chiefly to heat in its combinations with matter—to
dilatation and vaporization. I have already said, in
speaking of Dulong, that, in point of numerical pre¬
cision in the results of experimental physics, the
French are unrivalled. The talent which they have
shown in the construction of apparatus, skill in its use,
and patience in deducing results with due attention to
every numerical correction, have not been equalled
either in England or Germany, much less elsewhere.
We must, however, note that doubts were first
thrown upon the accuracy of Gay-Lussac’s coefficient Coefficient
of the expansion of the gases (0-375 of the vo-°f exPan'
lume at 32° for the expansion between 32° and 2120g1°s°s°anfj
Fahrenheit) by Rudberg a Swedish philosopher, who mercury ;
determined a new coefficient (0-3645). M. Reg- Rudberg
nault finds for air of the ordinary density a co- DulonS-
efficient nearly the same as that of Rudberg, but
differing slightly for the same fluid under differing
pressures, and also for the various gases.4 The ex¬
pansibility of all of these fluids appears to tend to
the same limiting value wdien they are sufficiently
attenuated. As a preliminary to these experiments,
the expansion of mercury was ascertained by its hy¬
drostatic equilibrium at different temperatures, as
had already been done by Dulong, and with almost
coincident results. The dilatation of mercury was
used to ascertain that of the glass vessels employed.
The irregularity of the dilatation of glass is one of (722.
1 Annales de Chimie, tom. Iv. (1833). -
2 I was led to polarize heat by transmission through mica films from having observed the extraordinary permeability of those
films to radiant heat, and from the facility of adapting them to tubes applied to the pile. The idea of using bundles of mica for
reflecting heat did not occur to me until some time after. But I cannot here omit mentioning a circumstance of which I only
became aware some years after the publication of my researches. In arranging my correspondence, I found some letters from
Sir David Brewster, with whom I had communicated as to the best means of polarizing heat, during my earliest and unsuccessful
attempts with common thermometers. In one of these letters he recommends, among other methods, the reflection of radiant
heat from mica bundles. This suggestion was not put in practice ; for, owing to change of residence and other circumstances,
my attention was diverted to other subjects, and only recalled, after a lapse of some years (as stated in the text), to the polari¬
zation of heat, by the invention of the Therrnomultiplier. Nor was Sir D. Brewster’s suggestion recollected by me until I ac¬
cidentally met with it (after another long interval), in the manner which £ h^ve just stated. I am glad to have an opportunity
of acknowledging the friendly assistance and encouragement in all matters of science which at an early age I received from him
when I was an obscure, though ardent student, and when he was my only scientific adviser.
3 1 have not thought it proper to go into farther details concerning my own experiments on radiant heat. Those who desire
more information will find it in Professor Powell’s Second Report on Radiant Heat, in the Brit. Assoc. Reports for 1840. But I
may here state, that M. Melloni’s first experiments on polarization were made with mica piles, furnished to him by myself in 1835.
4 M. Regnault’s experiments were published in 1841. Professor Magnus of Berlin was at the same time engaged on similar
experiments, and with nearly coincident results. The following table contains the summary of all these experiments :—
Dalton’s coefficient     0-391
Gay-Lussac’s coefficient       .,      0-375
Rudberg’s coefficient      0-3645
M. Regnault's coefficient (from the expansion observed under a constant pressure)  0-367
M. Regnault’s coefficient (from the elasticity observed under a constant volume)  0-3665
M. Magnus’coefficient (from the elasticity observed under a constant volume)  0-3665
Dalton’s experiments were made between 55° and 212°, and after allowing for the expansion of glass, he obtains for the relative
volumes of air at those temperatures 1000 and 1325, giving of the volume at 55° for 1° Fahr., or of the volume at 32°,
which agrees with the co-efficient given above. See Manchester Memoirs, vol. v., p. 598-9.
958
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
Irregular the great difficulties not only of these enquiries, but
dilatation generally, in constructing comparable thermometers,
of glass. It varieg s0 the composition of the glass
as to leave a serious amount of uncertainty in the
measure of temperatures above that of boiling water.
M. Regnault has had the perseverance himself to
graduate the thermometers which he uses.
(723.) These enquiries were in some measure introductory
to the determination of the elasticities of steam at
Regnault different temperatures, which had been already ascer-
onthe elas-tained with so much care by Dulong (nominally in
ticity of conjunction with Arago and other academicians), as
steam. to leave jittje need for repetiti0n, except on the
ground of the uncertainty of the indications at high
temperatures of the thermometers which they used.
All M. Regnault’s results are most carefully expressed
in terms of temperatures measured on an air thermo¬
meter corrected for the expansion of glass. They agree
well with those previously ascertained by Dulong.
(724.) In connection with this subject, the important law
M. Reg- 0f the latent heat of steam at different temperatures
latent heat ^as been correctly ascertained for the first time by M.
Regnault. Watt maintained that the sum of the
sensible and latent heats of steam is constant at
all temperatures : Southern and others, on the con¬
trary, believed that the latent heat has a constant
value, whatever be the temperature of vaporization.
M. Regnault shows that the true law is intermediate.
The latent heat diminishes as the sensible heat of steam
increases, but in a slower 'proportion.
(725.) Our author also followed the steps of his prede¬
cessor Dulong in verifying the law of Mariotte and Law of
Boyle on the compressibility of the gases. He found Ma^riotte
it to be indeed very approximately true, yet not ab- an °y
solutely so for any gas. For atmospheric air and for
most other gases the compression increases rather
faster than the strict proportionality to the pressures
would assign. In hydrogen gas the contrary is the
case. This result, together with that on the dilatation
of different gases, shows (if fully confirmed hereafter)
that mere simplicity or uniformity of result is not by
any means a sure ground of induction as to a law of
nature. That simplicity often appears to be predi¬
cable only of some abstract condition of matter which
we may assign or imagine, but which we rarely if
ever find realized amongst the bodies around us.
The preceding investigations, the result of an
amount of minute and assiduous labour almost fear¬
ful to contemplate, are to be found collected in the
21st volume of the Memoirs of the French Academy
of Sciences, which they entirely occupy.
M. Regnault has elsewhere published analogous
researches on the Specific Heat of a great variety of
substances, and on the theory and practice of Hygro- specjgc
metry, both of which are highly interesting and im- Heat and
portant, but which I have not here space to analyze. Hygrome-
He is also favourably known as the author of an try‘
excellent treatise on chemistry, and in fact sits in the
Institute as a member of the Chemical Section. He
now directs the manufactory of porcelain at Sevres;
and being still in the prime of life, much may yet be
hoped from his devotion to science.
(726.)
(727.)
CHAPTER VIL
ELECTRICITY—MA&NETISM—ELECTRO-MAGNETISM.
§ 1.—Galvani.—Discovery of Galvanism; Proper Animal Electricity.—The subject revived by
Nobili.—MM. Matteucci and Du Bois Reymond.
(728.) There are few discoverers in science whose posi-
Galvam. ^on jf. jg more difficult to assign with accuracy than
Galvani. Attaining at first, by a curious observa¬
tion patiently reflected on and carefully repeated in
detail, to the rank of the founder of a new science,
he was so far outstripped in its applications, that his
merit was soon in a measure overlooked, and his un¬
questionable discoveries ascribed to capricious acci¬
dent.
(729.) We find that a concurrence of circumstances con-
tion ^Ta" tributed to this result. Galvani was advanced in
discoverer years, and, it would appear, somewhat exhausted in
difficult to constitution, when he made his famous observation
estimate. on muscular contractions. He was an anatomist,
far more than either a chemist or physicist;—no
blame, surely, is to be attributed to him on that
account! His discovery was chiefly interesting in
his eyes, as illustrating the laws of sensation and
the source of nervous irritability. It was calculated
to throw great light on these most abstruse enquiries.
Groping to find the thread which should reveal to
him that labyrinth, is it surprising that he devoted
himself exclusively to those effects which gave him a
real promise of success ?—a promise held out still by
the same facts—still the envied goal of physiologists
—yet how little realized by the unremitting labours
of two subsequent generations!
Again, the almost irresistible temptation of con- (730.)
verting successful philosophers into heroes, at the Contrast of
expense ot their contemporaries, added to a less par- an(i y0ita.
donable wish to relieve the tedium of scientific dis¬
cussion, by the introduction of a lively, though ques¬
tionable anecdote, has induced the eulogists of Volta
to exalt his unqestionable claims by the deprecia¬
tion of those of his less widely known and less for¬
tunate countryman, Galvani. Their contrasts in cha-
Chap. VII., § 1.]
ELECTRICITY.—GALVANI.
959
racter and circumstances were sufficiently marked.
Galvani was a professional anatomist and physiolo¬
gist; Volta a physicist. Galvani was little known,
and had probably travelled little beyond the province
in which he resided; Volta was personally and ad¬
vantageously known in Paris and London. Galvani,
soon after his discovery, fell into undeserved political
disgrace, which undermined his health ; Volta lived
to an advanced age, his experiments and discoveries
rewarded by every honour which not only academic
authority could bestow, but which the almost uni¬
versal sway of Napoleon could render to his genius.
Galvani died prematurely, and whilst his best obser¬
vations were contested; Volta survived to nearly
the latest term of human life, having witnessed the
fruits of his great invention in the splendid disco¬
veries of Davy and Oersted.
(731.) The biographical particulars of Galvani’s life may
be passed over in a few words. The history of his
discoveries has been recently materially enlai'ged and
corrected, by the researches of the Academy of Bo¬
logna to which he belonged, and especially by those
of Professor Gherardi; it forms, together with his
collected writings, a ponderous quarto volume.1 The
diffuseness of the commentary, and that of Galvani’s
writings also, is a defect in this compilation, which
tends to weaken the unquestionable force of the evi¬
dence in his favour.
(732.) Luigi Galvani was born in 1737, and was
firsVexperi- Pronio^e<^ in 1762 to the chair of anatomy at Bo-
ments on logna, his native place, the seat of a most cele-
the Ner- brated university. He studied and taught his science
temS S^S" Wlt^ great success, and published several memoirs.
Probably he would have become still more widely
known, but that he was anticipated in some of his
observations (particularly on the organ of hearing)
by the celebrated Scarpa ; in consequence of which,
Galvani, with his customary modesty, suppressed
what had already become known through that able
anatomist. As early at least as 1780 (as we learn
from the researches of Gherardi, and the MSS. of
Galvani himself), he made experiments on muscu¬
lar contractions taking place by electric influence
from the electrical machine, the electrophorus, and
the Leyden phial.2 The experiments were made
on frogs in particular. This was ten years antece¬
dent to the commonly alleged casual discovery of
» galvanism. The experiments were continued in 1781
and 1782, when he drew up a paper (not published)
“ On the Nervous Force and its relation to Electri¬
city.”3 In 1786 he pursued the enquiry, with the
aid of his nephew Camillo Galvani; and the effect
of thunder-storms in occasioning muscular contrac¬
tions in the frog (which he had previously noticed),
was farther studied. He then designated the pre¬
pared frog as “the most delicate electrometer yet and on
discovered.”4 But this year was also the one 0f flectricity
his real discovery, namely, that muscular contrac- ^onTitT
tions are sometimes occasioned by causes remote it.
from any then known to be connected with electricity.
Camillo Galvani, pursuing his uncle’s experiments
on Atmospheric Electricity, had prepared some frogs,
by dividing them about the middle, and detaching a
portion of the lumbar nerves from the integuments,
leaving them in contact with a portion of the verte¬
bral column which was then suspended by an iron
hook. These prepared frogs were lying horizontally
on the top of an iron rail of a balcony on the third
floor of Galvani’s house, where he was in the habit of
observing the effects of atmospheric electricity. The
nephew noticed that when the hook or the vertebrae
Meie piessed on the rail by the finger or otherwise,
muscular contractions ensued, which he pointed out to
his uncle, who lost no time in repeating the observa¬
tion, which seems to have been made early in Sep¬
tember 1786.5 His experiments in this and the fol¬
lowing month are detailed, with the exact dates still
preserved, with this remarkable title in Galvani’s
hand-writing, — Esperimenti circa VEletricitd, dei
Metalli; and the results are formally drawn up
in a Latin Dissertation of 62 pages, bearing date
30th October 1786, forming the substance of the
most important section of his Commentary on the
Electric Forces^ &c., published five years later, but
differing from it in some important particulars.6
Thus it appears distinctly, that one metal alone
* iron—was used in producing the convulsion;^
whilst in the printed Commentary, the hooks are
said to be of brass or of copper. The explanation is,
that Galvani having become aware of the superior
efficacy of unlike metals in contact, described the ex¬
periment, not as it was first made, but as it might be
made with greater certainty. Yet, singularly enough,
this Dissertation is entitled,—De animali Electrici-
tate; showing, that in the short space of a few weeks,
he had abandoned his earliernotion of thewetaZs being
the source of the electricity, and ascribed the effects
to the proper electricity of the nerves and muscles.
1 Opere edite ed inedite del professore Luigi Galvani, raccolte e pubblicate per cura delV Accademia delle Scienze delV Instituto di
Bologna. Bologna, 1841. The copy which I use belongs to the lloyal Society of Edinburgh.
2 Rapporto, &c., p. 11 (in the work above cited). 3 p_
4 lb. p. 30. The expression is remarkable, because Volta is often regarded as the first who considered the frog in the aspect
of a mere electroscope. °
7 R<fPPorto’ PP; 33> 36- 6 Ib- P- 35> 36- were to be desired that this MS. were published in full
Ihe passage from the MS. is conclusive,—u Ranas itaque consueto more paratas uncino ferreo earum spinali medulla perfo¬
rata atque appensa, Septembris initio [1786] die vesperascente supra parapetto horizontaliter collocavimus. Uncinus ferream
laminam (namely, the top of the iron parapet or rail) tangebat; en motus in rana spontanei, varii, hand infrequentes ! Si digito
uncinulum adversus ferream superficiem premeretur, quiescentes excitabantur et toties ferme quoties hujusmodi pressio adhi-
beretur. —Rapporto, p. 36. r
960
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
(733.) Of these two very opposite aspects of this remark¬
able experiment, it might have been reasonably enough
anticipated, that one should be wholly erroneous.
This, however, is not the case. Galvani was justified
in both his inferences, although he unquestionably
believed that only one could be true. As a physio¬
logical anatomist, he not unnaturally adhered finally
to the opinion of vital or animal electricity being the
cause of the phenomenon which he had observed. Yol-
ta, on the other hand, already an experienced natural
philosopher5 though for a short time an entire con¬
vert to Galvani’s published opinions, maintained the
contact of metals, unlike either in kind or in their
mechanical condition, to be the source of the nervous
commotion; and whilst he was enabled to support his
opinion by very striking experiments, its popularity
was not unjustly perhaps exalted to the highest pitch
by the happy application which he made of it, to the
construction of that wonderful instrument, the vol¬
taic battery, which effectually withdrew attention for a
time from the comparatively feeble and obscure effects
of the electric power residing in the animal tissues.
(734.) The historian of science, well aware how far the in-
The proper ^r^nsjc importance of discoveries is from depending
o/the frog, upon the mere magnitude of their effects, and how
often the philosopher, dazzled by the splendour of a
new truth, overlooks some minute concomitant phe¬
nomenon which hereafter may rival or eclipse its
splendour,—readily recognises the perseverance with
which Galvani maintained his theory of animal elec¬
tricity as a part of the true philosophical character,
and therefore as enhancing his reputation. The
metallic arc which, by connecting the muscular part
of the limb with the root of the lumbar nerve, occa¬
sioned the convulsion, was to be regarded, on his
theory, as merely establishing equilibrium between
those parts to which the vital principle had commu¬
nicated an electric tension similar to that which sub¬
sists on the opposite surfaces of a charged plafe or
Leyden jar. Galvani gradually disembarassed his ex¬
periments from the suspicious presence of metals alto¬
gether. Taking the prepared hind-limb of a frog,
with the connected nerve entering the spine, he found
that when the latter was suffered simply to touch the
bare surface of any muscular part, and without the
Confirmed intervention of metal or any other conductor, a spasm
by Baron 0£ ^ immediately occurred.1 This important
Humboldt, experiment was repeated and varied in 1795, by the
celebrated Baron'Alexander von Humboldt, who pub¬
lished a paper on the subject in Gren's Journal, fully
confirming Galvani’s conclusions. Volta, on the other
hand, admitting the facts, strove to explain them on
the supposition, that they were due, like other electric
currents, merely to the heterogeneous nature of two
solid bodies, the muscle and the nerve brought into
opposition, and moistened by a conducting liquid.
Experiments instituted after a lapse of 30 years, with
the aid of new instruments, and vastly increased know¬
ledge of electric manifestations, have conclusively de¬
monstrated the accuracy in this respect of Galvani’s
reasoning in preference to Volta’s.
The publication of the results already noticed did (735.)
not take place till 1791 in his celebrated paper in the ^
Bolognese Transactions. The statement popularly
made by almost every writer (and which may be views,
traced to Alibert, one of the earliest historians of the
subject, but whose authority seems to be of little
weight), is that the discovery of Galvanism was made
in 1790, in Madame Galvani’s kitchen, where a frog
soup was being prepared for that lady’s repast, she
being at the time in delicate health. The absurdity
of the invention is evident from the history which
we have given, founded on unquestionable documents.
The memoir of 1791 was the resume of elaborate ex¬
periments continued with (apparently) little inter¬
ruption for eleven years ; and the most interesting
results had been digested in a Latin tract Jive years
before. All this shows at once great patience and
intelligence on the part of Galvani, who, perceiving
the difficulty and also the probable importance of
the subject (in a physiological view)—oscillating per¬
haps in some measure between the two vei'y opposite
opinions regarding the source of muscular excitement
which we have seen that he almost simultaneously
held,—postponed for so long a time the publication of
a discovery which he must have been sure would con¬
fer upon him a great reputation. By the time of his
publication his views had become fixed in favour of
animal electricity ; and he defended it in several suc¬
ceeding memoirs.
The unjust deposition of Galvani from his chair on (736.)
political grounds affected seriously his health andHls death*
energies. Perhaps his latest experiments were on the
Electricity of the Torpedo. He died 4th December
1798, aged only 61—happy perhaps in not having
witnessed the discovery of the Pile, which, by its as¬
tonishing results, was to throw into the shade Gal¬
vani’s more intricate and difficult studies.
To appreciate justly Galvani’s place in scientific (737.)
history, we must recollect three circumstances which His distin-
have often been overlooked,—.Fmt,that his discoveries
were the result of patient, ingenious, and protracted
research, not of a casual observation exciting ignorant
surprise. Secondly, That however deficient was Gal-
vani’s theory of animal electricity to explain all,
or even the most conspicuous facts witnessed by him,
it was a real discovery winch has been confirmed by
the latest and most scrupulous researches, and of a
physiological importance which can hardly be over¬
rated. Thirdly, Galvani'’s Commentary was received
at the time with enthusiasm, not only from the im¬
portance of the facts which it contained, but from the
1 The earliest notice of this result is found in one of Galvani’s autograph MSS., which appears certainly to date from 1786.
Rapporto, p. 48, § 18.
Chap. VII., § 2.]
ELECTRICITY.—GALVANI—NOBILI—VOLTA.
961
(738.)
Revival
of experi¬
ments on
animal
electricity
—Nobili.
ability shown by the author in discussing them.
There was no part of Europe in which Galvani’s ob¬
servations were not held to bear out his theory; and
the warmest eulogy of them is to be found in the
writings of Volta himself, who soon advocated a dif¬
ferent explanation. Volta calls animal electricity “a
great and luminous discovery which forms an epoch
in the annals of physical and medical science,” and as
“ proved to demonstration (ad evidenzd) by many ex¬
periments well contrived and accurately executed.” 1
Had there been as little novelty as has sometimes
been alleged in Galvani’s observations, they would
not have been heard of at once, and repeated in every
civilized country, nor have given birth to a new and
splendid science. Nothing then in progress, either
in the hands of Volta or of any one else, gave the
slightest clue to the invention of the Pile, which, but
for Galvani, might have been yet undiscovered.
Revival of Experiments on Animal Electricity.—
The grand discovery of Oersted, which gave a fresh im¬
pulse to so many branches of science, revived likewise
the subject of the proper electricity of the animal tis¬
sues, which had been well-nigh forgotten since the
death of its discoverer Galvani. Twenty-nine years
later, in 1827, Nobili of Florence demonstrated the ex¬
istence of what has been termed “ The current of the
frog.” We have seen that a momentary spasm is
produced when a circuit is completed, including the
muscle and nerve of the recently dead animal. But
by the aid of that admirable instrument the Galvan¬
ometer, Nobili succeeded in showing that a continu¬
ous current of positive electricity constantly passes
from the feet to the head of the frog. This he de¬
tected by placing the feet of the animal in connec¬
tion with one end of the galvanometer wire, and its
spine with the other (the whole being properly insu¬
lated), when the needle of the instrument was per¬
manently deflected to the amount of 5° or more—
indicating the passage of a stream of electricity in the
direction already mentioned, which continued for se¬
veral hours after death. Strange to say, Nobili mis¬
apprehended the nature of the phenomenon, ascrib¬
ing it to Thermo-Electricity, though he ought to
have been undeceived by the singular intensity of
the animal current, which, feeble as it is, can force
its way along thousands of feet, or even some miles of
fine wire.2
These experiments were renewed in 1837 by M. (739.)
Matteucci of Pisa, who has the merit of reviving the ,Mat'
original and cori’ect opinion of Galvani as to the vital Du gois
source of this electricity. To his researches, and the Raymond,
still later ones of Dr Du Bois Reymond of Berlin, we
owe the knowledge of most of the facts as yet ascer¬
tained in this most difficult and obscure branch of
enquiry, where the sources of error are so numerous
as only to be eluded by consummate skill on the part
of the experimenter. It appears to be established
that the vital electricity exists both in the muscles
and in the nerves of many, probably of all animals
when living or recently dead ; that therefore the frog
current of Nobili is only a single case of the general
muscular current, and that the latter arises from the
electro-motive action of even the minutest fibres of
which a muscle is composed—the genei'al law being
(according to Dr Du Bois Reymond) that positive elec¬
tricity moves from the transverse section to the longi¬
tudinal section of a muscle or a nerve, or any portion
of either. Finally, the last-named writer has shown,
to the satisfaction of many eminent men who have
witnessed his experiments, that powerful muscular
contraction, whether induced by stinruli or the result
of volition, tends to diminish the force of the natural
muscular current. This he demonstrated first on the
frog poisoned by strychnine, but afterwards on the
muscles of his own arm, in which by voluntary con¬
traction he could diminish at will the force of the
natural current, which in the state of rest is directed
from the shoulder to the hand.
2. Volta.—Progress of Discovery in Common and Atmospheric Electricity—The Electro-motive
Theory—Voltaic Pile—Chemical Analogies and Decomposition—Fabbroni; Nicholson and
Carlisle.
(740.) Volta was the first among philosophers whose
Volta. career lay solely in the study of electricity. Franklin
and iEpinus, Beccaria and Wilke, Cavendish and
Coulomb, gave it only a share oftheir attention ; but
Volta was from boyhood exclusively an electrician.
Such devotion deserved success, and he achieved it.
He was already famous, and an honorary fellow of
the Royal Society, long before his principal discovery
of the Pile. A review of his career may therefore
be conveniently divided into two parts—what con¬
cerns ordinary and atmospheric Electricity; and the
new doctrine of Galvanism and the Electro-motive
force.
I. Alessandro Volta was born at Como, of a noble
family, in 1745. His first paper on Electricity was ad- experi- ^
dressed to Beccaria at the age of eighteen. But it was merits—
not till 1775 3 * that he published a description of the hisElectro-
Electrophorus, an ingenious instrument in which a condenser11
conducting body becomes electrified an indefinite num¬
ber of times in succession by being brought near to an
1 Opere del Volta, ii., p. 13, 14.
2 The galvanometer of Du Bois Reymond contains 3-17 English miles of wire, in 24,160 coils.
3 See the letter to Priestley in the First volume of Volta’s Works.
VOL. I. 6 F
962
MATHEMATICAL AND PHYSICAL SCIENCE.
excited cake of pitch and resin. This charge is re¬
ceived by induction merely ; and as it expends none
of the electricity connected with the pitch, the suc¬
cessive charges are precisely equal, a circumstance
which enabled Volta very simply to give a nume¬
rical value to the amounts of electricity used in his
experiments, as they were given by one, two, or
more contacts with the electrophorus. The Con¬
denser, an ingenious and useful instrument for ac¬
cumulating small charges of electricity until they
attain a measurable amount, or cause divergence in
the electrometer, was described by Volta in 1782 in
the Transactions of the Royal Society, its construction
having occurred to him in following out the idea of
the electrophorus. This instrument was ultimately
of essential service in establishing his theory of Elec¬
tro-motion. The theory of both the electrophorus
and condenser had been indicated by iEpinus some
time before Volta constructed them ; but he did not
apply them in the practical way which Volta did to
the improvement of his science. Volta being, be¬
sides, unquestionably ignorant of iEpinus’s labours,
has been generally and justly regarded as the real
inventor. Though both of these instruments depend
on the principle of induced electricity, Volta never
appears to have possessed correct views on that sub¬
ject, but throughout his writings speaks of electrical
atmospheres, and uses other phrases of the old school
of electricians, showing a certain vagueness in his
conception which a study of the writings of his able
contemporaries, TEpinus and Coulomb, would have
dissipated.
(742.) But Volta’s tact was unconnected with any tinge
Straw8 mathematical reasoning: his experimental ability,
Electrome- his caution, and his persevering devotion to one sub-
ter. ject, enabled him, however, to advance science in a
different way. Even the simple Straw Electrometer
which he generally used, was tested by him with
such skill and care as to lead to correct results in
the measurement of small quantities of electricity.
M.Biot has indeed criticised his preference for so rude
an instrument, which depends, mathematically con¬
sidered, upon repulsions of a very complicated cha¬
racter; but as Volta carefully tested its comparabi¬
lity up to 30° of divergence, and found it proportional
to the force, there is no doubt that he was justi¬
fied in relying on its use; and Arago, in opposition
to his colleague, maintains that Volta’s essay on the
Straw Electrometer is one of the best examples of
experimental research which can be put into the stu¬
dent’s hands. This instrument is described in the
first of a series of letters to Lichtenberg collected in
the first volume of his works; the subject of these
letters being the Electricity of the Atmosphere.
(743.) The important experiments of Dalibard and Frank-
ric^Iectid* ^n’ rePeate(l with fhtal consequences by llichmann,
cit * had demonstrated the perfect resemblance or rather
[Diss. VI.
identity of lightning and electricity. Lemonnier dis¬
covered the fact of electricity being manifested when
no thunderstorm threatened, and even when the sky
was cloudless, and that it was subject to diurnal va¬
riations of intensity. Beccaria farther ascertained
that with a clear atmosphere the electricity of the
air is always positive. De Saussure, Deluc, and
Volta continued the interesting enquiry. The
first, availing himself of the known action of points
to draw off electricity, connected his electrometer
with a pointed rod two or three feet in length.
Volta substituted for this the flame of a lamp pro¬
ducing a heated current of air, which has a won¬
derful power of drawing off electricity; and he sug¬
gested the employment of large fires during thunder¬
storms in preference to metallic conductors. Volta
hesitates not to ascribe to the worshippers of Jupiter
Tonans the secret intention to draw off the electricity
of heaven by the action of the flames on the altar.1
Arago has ingeniously suggested that a statistical
enquiry as to the frequency of thunderstorms in the
neighbourhood of extensive iron-smelting furnaces
might test the value of this safeguard. The straw
electrometer which Volta connected with his appara¬
tus was capable (by a gradation of instruments of
greater or less delicacy) of measuring numerically
the force of charges from 1000 to 2000 units.
That the chief source of atmospheric electricity is (744.)
evaporation appears first to have occurred to Volta, Due^eva'
and to have been first demonstrated by experiments
made either with him or by his suggestion, at Paris
in 1780, by Lavoisier and Laplace. The history is
given by Volta himself in a paper in the Philosophical
Transactions for 1782. When water is thrown upon
an insulated heated body so that evaporation takes
place, or when hot coals are thrown into an insulated
vessel of water, the hot body is usually found to be
electrified negatively. Volta has very candidly stated
the inversions of effect which occasionally occur, and
which still throw some doubt upon the precise signi¬
ficance of this very important experiment. Later
experimenters have thought that absolutely pure
water developes no electricity: this, however, will
not affect the validity of the explanation of the origin
of atmospheric electricity. To prevent misappre¬
hension it may be observed that the astonishing de-
velopement of electricity from high-pressure steam
escaping through a small aperture, as lately observed
by Mr Armstrong, appears, from the experiments of
Dr Faraday, to depend on an entirely different cause.
Of Volta’s electrical theory of Hail we cannot now
stop to speak.
Volta, who understood chemistry and who always (745.)
took a peculiar interest in the inflammable gases, 3
contrived the Eudiometer which is often erroneously meter
called Cavendish’s, having been frequently used by
that philosopher. The amount of oxygen in the air
Opere, vol. i., part 2., p. 205. Volta’s contrivance dates from the beginning of 1787. Bennett imagined it independently.
Chap. VII., § 2.]
ELECTRICITY—VOLTA.
963
is tested by mixing the latter in known proportions —“Le sujet des decouvertes, et des recherches
with hydrogen in a close vessel through which an dont je vais vous entretenir, Monsieur, est Vetec*-
electric spark can be passed. Detonation takes tricite animale.” In the course of the paper, how-
place, and the quantity of gas which has vanished (by ever, he distinctly states that whilst he agrees with
conversion into water) measures the amountofogygen Galvani in considering that the convulsions of the
which has combined with hydrogen in the experi- frog, obtained with homogeneous conductors, are
ment. It was for a long period employed as by far due to a proper animal electricity (§§ 12, 16), the
(746 ) tllG l>est meanS of testinS the Purit7 of air- more powerful effects occasioned by the contact of
Practical A11 the Preceding labours of Volta (and I do not in- unlike metals are caused by “ common electricity ”
character tend to touch on any minor ones) have evidently an developed at the junction, and having the nature, not
otyVolta’s intensely practical character. His aim throughout of a discharge, but of a continued stream. He re-
inven ions. was to improve the instrumental means of detecting peats and modifies Galvani’s experiments on animals,
and measuring electricity, and to detect and measure cold and warm-blooded, and makes interesting ob¬
it as it occurred in practice, rather than to form theo- servations on the excitement of the nerves of taste
v ries of its nature.1 Even the discovery of galvanism, and sight by the contact of unlike metals. The con-
which vividly excited his interest, only partially di- elusion of his paper is in opposition to its earlier
verted him from his scientific destiny. Volta will portion. He expresses a grave doubt whether there
indeed be always remembered as the author of the be any vital electricity in the matter.
plausible theory of electro-motion, and as having The induction of Volta was imperfect in this, that (748.)
corrected the too exclusive doctrine of Galvani con- he did not prove that the effects which he attributed Volta re-
cerning the sources of electric excitement; but his with great probability to the contact of metals pro- piv]e8 the
real claim to immortality is the invention of the Pile, duced any other recognised electric effect than the phy- SSaT
T° thiS part °f tlie hist0IT we therefore proceed. siological ones. Galvani had gone very nearly as far.
History of IL When Galvani announced his discoveries in He had even hesitated between the terms animal
the Pile tlie Bolognese Transactions in 1791,2 Volta was electricity and electricity of metals; he had considered
—Volta’s Professor of Physics at Pavia, having been appointed the frog as a very sensitive electrometer, exactly as
persyona’ t0 that P°st in 1^4- As has been mentioned in a Volta did; and the manner of so using and applying
galvanism. former section, the announcement of these researches it is ascribed by the latter in this memoir to Galvani,
excited the immediate attention of electricians and who having thus invented the instrument which
anatomists in every part of Europe. Of course Italy for years served alone to indicate the presence of the
was not exempted from the general impulse. In that new species of electricity—and having also described
country physiological observations have always been accurately the influence of the heterogeneous metals
prosecuted with interest and success; and indeed it in aiding the results—left to Volta only the credit of
has never been deficient in persons of ability, whether the assertion that in some instances the effect was
in physical or in purely mathematical enquiries, since due to the metals themselves, in others to the natural
the very dawn of letters, at which time Italy made so electricity of the animal frame. Under these cir-
distinguished a figure in literary progress. Volta, cumstances, I think that the award of the Copley
Aldini, Valli, and Spallanzani were all, at the time Medal by the Royal Society to Volta, rather than to
of which I now speak, actively engaged in the Galvani, was a questionable decision: the great va-
pursuit of science; and Galvani’s opinion that the lue of Volta’s paper, at the time, was undoubtedly
commotion of the frog by the connection of the that it directed the attention of English experimen-
muscle and nerve through a <£ conducting arc” of ters to Galvani’s discoveries, then quite recent and
metal was due solely to animal electricity, was gene- probably imperfectly known. 4
rally adopted, and by none more cordially than by Many publications followed. I shall only notice (749 >
Volta in a letter and memoirs published in Brug- that by Dr Fowler of Edinburgh (afterwards of Salis-Robison’s
natelli's Journal early in 1792. These were speedily bury), which is remarkable as containing a letter by a.nticiPa-
toCavallo8 followed hJ tw0 Otters to Cavallo, dated October of Professor John Robison (335), who first thought of Voka’s
' the same year, and communicated to the Royal So- increasing the effect of heterogeneous contact by using pile,
ciety of London, in acknowledgement, as the author “ a number of pieces of zinc made of the size of a shil-
states, of the honour recently done him of electing ling, and making them up into a rouleau with as
him an Honorary Fellow. The title of this com- many shillings.” We have here unquestionably the
munication deserves notice, — “ Account of some first idea of the pile, which moreover was actually
Discoveries made by Mr Galvani of Bologna, with constructed. This was in May 1793. It was only
Experiments and Observations on them;”3 and applied, however, to excite the nerves of the senses,
also the first sentence (the letters are in French), In various scattered memoirs, from 1793 to 1796, (750.)
1 His arguments as to the primary law of electric attractions and repulsions, are wholly inexact. His electrometer was unfitted
for such enquiries.
2 Vol. vii. His paper was reprinted separately at Modena in 1792. 3 Philosophical Transactions, 1793.
4 See the grounds of the award stated by Sir Joseph Banks. Weld, Hist. R. Society, ii., 202.
964
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
Volta’s
theory of
electro¬
motion.
Invention
of the pile,
Repulsion
due to con
tact of
metals.
we find Volta gradually insisting more on the purely
mechanical nature of the electrical excitement. The
last-named year produced an important letter to
Gren of Halle,1 which contains the real germ of the
invention of the pile, though it has been little taken
notice of. We there find conducting bodies divided
into two classes, primary and secondary; the first
including metals, metallic ores, and charcoal; the se¬
cond liquids, solutions, animal tissues, &c. The first
class he also called motors. Using the prepared
frog always as an indicator, he tried the effect of
combining three or more elements of the two kinds.
He found that a double combination of three ele¬
ments, when arranged so that their order was re¬
versed, neutralized each other, or produced no
spasm ; on the contrary, when the two combinations
conspired in direction, the convulsions were in¬
creased (§ § xii., xv., xix.). This appears to define the
date of Volta’s discovery of the principle of the pile
—that, namely, of superadding minute effects—to he
August 1796. The form of the arrangement resembled
that afterwards adopted in the Couronne des Tasses.
The second letter to Gren, dated the same month of
August 1796, contains the important discovery (the
most important abstractly of any due to Volta), that
the electricity set in motion by the contact of unlike
metals may, by means of the condenser (due also to
him), be made evident by the usual effect of repul¬
sion on the common electrometer:—thus when zinc
and silver are used, the former is positive, the latter
negative, and so of other metals. Volta used for
■ this experiment Nicholson’s ingenious modification of
his own condenser, called a Revolving Doubler. It
must be owned that the experiment, in its simplest
form, is difficult of repetition, and that Nicholson’s
instrument sometimes gives delusive results. But
Volta’s great address in practical electricity, and his
fairness in stating his results, leave no doubt of the
reality of his discovery, which evidently for the first
time eliminated the physiological element of Gal-
vani’s experiments, leaving the recognised mechanical
effects of electricity due to the contact of unlike
metals; and, therefore, deserved the highest honour
which could be bestowed. Pfaff had already con¬
structed a table of the electro-motive power of metals
by their actions on the frog, in which zinc stood at
one end, carbon at the other. But one of the most
curious parts of the paper by Volta is the evidence of
a strong suspicion which had crossed his mind, and
been for a time entertained, that in his experiments
with combinations of three elements—two metallic,
and one humid—the electricity was developed sepa¬
rately at the contacts of the latter with the two for¬
mer, and that the resulting current was merely the
difference of the two in favour of the stronger. Truly
in this whole history we may see how often first sug¬
gestions have a peculiar and intuitive worth, which
reflection and controversy often only obscure ! This
is, of course, the case rather in the research of causes
than of the means of rendering discovery practical.
Whilst Volta was thus maintaining the opinion (751).
that the electricity excited by the contact of metals Fabbroni
was entirely mechanical, and due to contact merely ; the chemi-
—and whilst Galvani, his relative Aldini, and others, Cal origin
maintained strenuously the vital theory, in which they galvan-
were substantially confirmed by no less authoritieslsm’
than Wells and Baron von Humboldt—a third school
appeared, at first little popular, represented by Fab-
broni, a Tuscan chemist and natural philosopher of
no small merit. His papers published, I believe,
in 1799, though written several years previously, and
some as far back as 1792, of which a full abstract is
given in Nicolson’s Journal,2 show great acuteness.
He attributed the effects of the contact of metals to
a chemical action developed at the place of contact.
He referred to Sulzer’s experiment of the taste of
heterogeneous metals applied to the tongue—and to
many instances of the rapid oxidation of heterogeneous
metals in contact, when exposed to heat and mois¬
ture. Amongst others, by a remarkable anticipation
of one of the most curious applications of the elec¬
tro-chemical theory, he notices the oxidation of the
copper sheathing of ships. Without “ excluding all
electrical influence from the prodigious effects of gal¬
vanism,” he infers that there are chemical forces
“ exerted with the swiftness of lightning,” to which
the physiological effects, and perhaps some others
ascribed to electricity, are probably due. Thus, he
says, “ the experiment of Sulzer is nothing more
than a combustion or chemical operation, as is proved
not only by its result but by its duration ; for elec¬
tricity acts always instantaneously, whereas the ef¬
fect of chemical affinities continues so long as the
re-agents are not saturated.” The weak point of
Volta’s theory of electro-motion is here cleverly hit.
That effects indefinitely prolonged, capable of pro¬
ducing mechanical, chemical, and vital changes,
without any mutual action between the touching
bodies, save mere pressure, appears indeed a paradox
startling even to a first inventor, but which, when
maintained by successive generations of able men,
may rank as a delusion more memorable than the
phlogistic theory of the older chemists. Fabbroni
did not himself pursue his ingenious speculations,
but his papers, though now almost forgotten, acted
powerfully on the minds of his contemporaries, as
we shall see in the next section. He died at the age
of 70, in 1822, having spent most of his life in pa¬
triotic and useful labours in his native country.3
We have seen that already in 1796 Volta had ar- (752.)
rived at a knowledge of the principle that the electric ^
effect of the metals might be increased by combining his pile,
two sets of triple elements similarly disposed, which, and its ef-
unknown to him, Robison had already done (749). fects-
1 Volta, Opere, vol. ii., part 2. 2 In quarto, vol. iv. (1800). 3 See an account of him in the third volume of Cuvier’s Eloges.
Chap. VIL, § 2.] ELECTRICITY—VOLTA—NICHOLSON AND CARLISLE.
965
(753.)
(754.)
Nicholson
and Car¬
lisle obtain
chemical
effects
from the
pile.
But three years seem to have elapsed before he was
led to the invention of the pile, although it is in truth
nothing more than the same arrangement frequently
repeated. In March 1800 he wrote from Como a
letter to Sir Joseph Banks, which was printed in the
Philosophical Transactions for the same year, and in
which he describes the Pile and the Couronne des Tos¬
ses. The former consisted of 20 or more copper or sil¬
ver coins interlaid with as many disks of tin or zinc,
and others of paper or leather, soaked in water or
brine. The same order of sequence of the three elements
was carefully preserved throughout; and the whole
formed a vertical pile or rouleau. Several such piles
could be used together. The effects were—1. The ready
excitement of the common electrometer by the aid of
the condenser ; 2. The production of smart shocks
through the hands and arms, similar to those pro¬
duced by the torpedo ; 3. The production of vivid
sensations of taste, of sound in the ears, and of flashes
of light. There was nothing new in these effects (it
may be seen) except that their intensity was much
exalted, and the verification of the metallic theory
was thereby rendered more easy. Volta attributes
the action to the effect of “ simple contact” of the me¬
tals, allowing to the fluid element no other share than
that of conducting sufficiently, but not too rapidly,
the impulse thus excited. Having an eye probably to
Fabbroni’s opinions, he insists on the superior effects
obtained with saline and alcaline fluids, and with hot
in preference to cold fluids, being explicable solely
by their increased conducting power. He justly de¬
scribes the effects of the pile as similar to those of
an immense electric battery with a very feeble charge;
only the action is continuous, instead of intermittent.
But the invention had scarcely become known in
London when the importance of the pile, as an in¬
strument of discovery, was keenly appreciated in
consequence of one capital discovery.
Nicholson, a good electrician and chemist, and
Carlisle (afterwards Sir Anthony), a medical man,
were the first in England to construct one of Volta’s
piles. It consisted first of 17, afterwards of 36, half-
crowns, with as many disks of zinc and of paste¬
board, soaked in salt water. Experimenting upon
the electrical effects of the pile, they used a drop of
water “ to make sure the contacts” upon the upper
plate. Carlisle first observed a disengagement of
gas round the wire which the water moistened.
Nicholson suspected it to be hydrogen, and pro¬
posed to break the circuit by enclosing water in a
tube between the two wires. This was accordingly
done on the 2d May 1800, within a month of the
arrival in England of the first four pages of Volta’s
letter to Sir J. Banks, which preceded the remainder
by a considerable space of time. The brass wire in
the water tube, which was connected with the posi¬
tive end of the pile, became tarnished and black,
whilst minute bubbles of gas were evolved from the
other, to the amount of ygth of a cubic inch in 21-
hours. Being mixed with an equal quantity of com¬
mon air, and a lighted waxed thread being applied,
it exploded. It was, therefore, concluded to be hy¬
drogen derived from the decomposition of the water,
whose oxygen had combined with the brass of the
positive wire.1 Nicholson, it appears, was well ac¬
quainted with Fabbroni’s writings on the relation of
galvanism to chemical action ; and in the very paper
where he describes Volta’s pile and his own discovery,
he expresses his astonishment that Volta should
have taken no notice of Fabbroni’s results, or of the
rapid oxidation of zinc in contact with other metals
which appears in the pile, and which had been no¬
ticed by Fabbroni in every case where two metals
differing in oxidability are placed in water, and
in contact with each other. The experiment was
repeated at Vienna, and then by Volta himself, who
called attention to an experiment by three Dutch
chemists, Pacts, Van Troostwyk, and Dieman, who
had decomposed water by common electricity in
1789.
Volta, himself, however, did not enter with zeal (755.)
upon this new career ; he even left to others the Volta re-
task of improving the form and increasing the energy ^nctkms8"
of his battery, which was first done by the useful from Na-
arrangement of Cruickshank. He was now ap-poleon, and
preaching his 60th year, and seems to have ^)een ^titute of
not indisposed to pass an old age of ease, and to re- France—
ceive in tranquillity the marks of distinction which
were showered upon him. In 1801 Napoleon called
him to Paris, attended the meeting of the Institute
where Volta explained his theory of the pile, caused
to be voted to him on the spot a gold medal, and
sent him home with a valuable present in money.
He was then made a Senator, finally a Count: he was
also made an Associate of the Institute in 1802.
No scientific discovery ever excited the enthusiasm
of Napoleon to the same degree as that of the
Pile. Pie even extemporized a theory of life from
its phenomena, comparing the vertebral column
in man to the pile, the bladder being the posi¬
tive and the liver the negative pole. An eminent
medical chemist, Dr Prout, has seriously main¬
tained a somewhat similar hypothesis. The fa¬
vours lavished on Volta excited, perhaps, some jea¬
lousy amongst the French philosophers; for it is
remarkable how little was added in France to the
progress of the revived science of electricity. The
French ruler, however, had himself in some measure
to blame for this ; for the rigid exclusion of foreign,
and especially of English publications, for a number
of years, was felt to be highly injurious, and was in
vain remonstrated against by Berthollet and others.
Volta survived his great invention above a quar- (756)
ter of a century. He died 5th March 1827, aged 82. His death.
Nicholson’s Journal (series in quarto), iv., 182.
966
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
(757.)
His scien¬
tific cha¬
racter.
(758.)
History of
the pile of
Volta con¬
tinued.
(759.)
Cruick-
shanks,
Wollaston,
Davy.
His scientific character is easily summed up. He
was patient, intelligent, and devoted to science from
youth to age. He had, in an eminent degree, that
patience and tenacity of purpose and of interest
which Newton described as the chief attributes of his
own genius. He had the candour which is more
especially to be desired in the experimentalist; and
he wrote without pretension, and generally clearly,
though not without that diffuseness which is often
associated with the use of the Italian language
even in matters of science. On the other hand, his
intellect may be rather described as opening itself to
conviction, than as forcing its way by a native power
of penetration to great results. His taste and his
talent lay far more in experimental than in abstract
reasoning. His explanations of the effects which he
observed were often involved and obscure; yet he had
a very happy talent of combination, which led him
to effect what others only talked about. His instru¬
mental inventions, including the pile, were his hap¬
piest efforts. His theories, on the other hand, were
surrounded, even in his own mind, with a certain
obscurity. Even the contact theory, with its manifold
paradoxes, was perhaps only vigorously carried out
by him under the excitement of an active contro¬
versy. The invention of the pile may, in very many
respects, be placed on a par with that of the steam-
engine. The results of the former were indeed more
interesting, immediately, to pure science; the latter
to the arts of life and the needs of civilization. Yet,
after half a century, this distinction can hardly be
drawn with severity. The rapid pace of steam is
insufficient for our demands. The electric wire con¬
veys to its destination, ere the locomotive has time to
start on its journey, tidings of joy and sorrow—life
and death—of victories won, and kingdoms lost.
§ 3. Sir Humphry Davy. Progress of Voltaic Electricity—Electro-Chemistry ; Berzelius.—
Davy's Invention of the Safety-Lamp.—Wollaston; his Electrical and other Observations.
Contrast of his Character with that of Davy.
The pile of Volta was, in one sense, rather a
means of discovery than a discovery itself. Volta
had neither a just theory of the source of power
which he invented, nor was he successful in applying
it to any important research. The discovery of its
chemical efficiency by Nicholson and Carlisle, stimu¬
lated, as we have seen, for a short time his interest
and curiosity; but he never seriously attached him¬
self to this line of discovery. His subsequent papers
are chiefly controversial, in support of the Contact
theory. The generation, as well as the expendi¬
ture of chemical forces by the pile, consequently re¬
mained, as far as he was concerned, in complete
obscurity.
The invention of the pile having been communi¬
cated to the world through the Royal Society, natu¬
rally gave an impulse to English electricians and che¬
mists. The first discoverers of its chemical energy
did not however themselves prosecute their experi¬
ments to a great extent, but Cruickshanks decom¬
posed salts and revived the metals by the voltaic
current, whilst he improved the form of the appa¬
ratus in an important manner. Colonel Haldane
ascertained the significant fact that the action of the
pile cannot be continued in an atmosphere deprived
of its oxygen. Hisinger and Berzelius, carrying out
Cruickshanks’ experiments, showed that, generally
in the decomposition of compounds, the alcaline and
metallic elements appear to be attracted towards the
negative wire of the battery, and the acids to the po¬
sitive one. In the mean time, Davy and Wollaston
appeared on the arena, and the former especially filled
so important a part in the history of science for the
next twenty years, that we can hardly give his name
too great a prominence in a review of the character¬
istics of the period. The constitution of Davy’s mind
was also more than usually interesting, and his career
of discovery, short, brilliant, and decisive, is at once
one of the most instructive and remarkable of
those which we have to consider. The contrast be¬
tween him and his contemporary, Wollaston, was
one of those curious antitheses of really great minds
which occasionally occur in such close connection,
and with such prominent relief, as to compel rather
than invite a comparison between them. It is an
instructive lesson to observe, how natures, the most
unlike, cultivated in a school the most opposite, may
yet, when both directed by a common impulse to
similar objects, promote the development of truth,
and the cause of scientific discovery.
Sir Humphry Davy was born at Penzance on the
17th December 1778. His was an ardent boyhood.
Educated in a manner somewhat irregular, and with
only the ordinary advantages of a remote country town,
his talents appeared in the earnestness with which he
cultivated at once the most various branches of know¬
ledge and speculation. He was fond of metaphysics;
he was fond of experiment; he was an ardent student
of nature ; and he possessed at an early age poetic
powers, which, had they been cultivated, would, in the
opinion of competent judges, have made him as emi¬
nent in literature as he became in science. All these
tastes endured throughout life. Business could not
stifle them,—even the approach of death was un¬
able to extinguish them. The reveries of his boy¬
hood on the sea-worn cliffs of Mount’s Bay, may yet
be traced in many of the pages dictated during the
last year of his life amidst the ruins of the Coli¬
seum. But the physical sciences—those more em¬
phatically called at that time chemical—speedily
attracted and absorbed his most earnest attention.
The philosophy of the imponderables—of Light, Heat,
(760.)
Sir Hum¬
phry Davy
—his early
history and
remark¬
able genius.
Chap. VIL, § 3.]
ELECTRICITY.—DAVY.
967
and Electricity—was the subject of his earliest, and
also that of his happiest essays. He was a very able
chemist in the strictest sense of the word, although
his ardour and his rapidity of generalizing might seem
to unfit him, in some measure, for a pursuit which
requires such intense watchfulness with regard to mi-
nutbe, such patient weighings of fractions of a grain,
such frequent though easy calculations. To Caven¬
dish and Dalton, his great contemporaries—to whom
we may now add Wollaston—these things were a
pleasure in themselves ; to Davy they must ever have
been irksome indispensables to the discovery of truth.
But, in fact, Davy’s discoveries were almost indepen¬
dent of such quantitative details: Numerical rela¬
tions, and harmony of proportion, did not affect his
mind with pleasure, which possibly was one reason
of his deficient appreciation of works of art, the
more remarkable from his poetic temperament.
Dalton’s doctrine of atomic combinations was (as we
have seen) slowly and doubtfully received by him
whilst Wollaston perceived its truth instantaneously.
A keener relish for such relations might most natu¬
rally have led Davy to an anticipation of Mr Fara¬
day’s notable discovery of the definite character of
electrical decomposition, and the coincidence of the
Electro-chemical proportions for different bodies with
their atomic weights.
His^first r^^ie earty PaPers °f Davy refer chiefly to Heat,
papers, and Light, and Electricity. He was, in fact, a physicist
experi- more than a chemist. Whilst yet a surgeon’s ap-
ments on prentice at Penzance, he satisfied himself of the im-
oxide. materiality of heat, which he illustrated by some in¬
genious experiments, in which, concurring unawares
with the conclusions of his future patron Rumford,
he laid one foundation of his promotion. Removed
to a sphere of really scientific activity at Clifton,
under Dr Beddoes,1 he executed those striking re¬
searches in pneumatic chemistry and the physiologi¬
cal effects of breathing various gases which gave him
his first reputation; researches so arduous and full of
risk as to require a chemist in the vigour of life,
and urged by an unextinguishable thirst for dis¬
covery, to undertake them. Even his brilliant dis¬
covery of the effects of inhaling nitrous oxide brought
no competitor into the field; and the use of anses-
thetics, which might naturally have followed—the
greatest discovery (if we except, perhaps, that of
vaccination) for the relief of suffering humanity
made in any age—was delayed for another generation.
But so it was in all his tinumphs. He never seemed
to drain the cup of discovery. He quaffed only its
freshest part. He felt the impulse of an unlimited
command of resources. He carried on rapidly, and
seemingly without order, several investigations at
once. As in conversation he is described as seem¬
ing to know what one was going to say before utter¬
ing it,—-he had the art of divining things complex
and obscure. Seizing on results, he left to others the
not-inconsiderable merit, as well as labour, of pur¬
suing the details. Keenly alive as he was to the
value of fame, and the applause which his talents
soon obtained for him, he left enough of both for his
friends ; his contemporaries, as well as his successors,
were enabled to weave a chaplet from the laurels
which he had not stooped to gather.
These remarks apply quite as strongly to his dis- (762.)
coveries in the laws and facts of electro-chemical de- ^e^iove<i
composition—those on which his fame most securely R0yai jn.
rests. Promoted in 1801 to a situation in the Labo- stitution—
ratory of the Royal Institution in London, he attached exPeri-
himself to the study of galvanism in the interval of^”^^,011
the other and more purely chemical pursuits which electricity,
the duties of his situation required. He had already,
at Clifton, made experiments with the pile of Volta,
and taken part in the discussion of its theory and
effects, then (as we have seen) so actively carried on
in Britain. In his papers of that period we find not
only excellent experiments, but happy and just rea¬
soning. The chemical theory of the pile—namely,
that the electrical effects observed by Galvani and
Volta are due solely or chiefly to the chemical ac¬
tion of the fluid element on the metals—was more
strongly embraced by him then than afterwards. In
November 1800 he concluded that “ the pile of
Volta acts only when the conducting substance be¬
tween the plates is capable of oxidating the zinc ;
and that in proportion as a greater quantity of oxy¬
gen enters into combination with the zinc in a given
time, so in proportion is the power of the pile to de¬
compose water and to give the shock greater.” He
concludes that “ the chemical changes connected
with” oxidation “ are somehow the cause of the elec¬
trical effect it produces.”2 His views on this sub¬
ject underwent some modification afterwards. In
his Elements of Chemical Philosophy, pub! i sh ed twelve
years later, we find the following statement of his
opinions on the subject:—“ Electrical effects are exhi¬
bited by the same bodies acting as masses, which
produce chemical phenomena when acting by their
particles ; it is, therefore, not improbable that the
primary cause of both may be the same.” A little
further on he adds :—“ They,” speaking of electrical
and chemical energies, “ are conceived to be dis¬
tinct phenomena, but produced by the same power
acting in the one case on masses, in the other on par¬
ticles.”3
1 Davy hit off his principal’s character in a single sentence,—“ Beddoes had talents which would have exalted him to the pin¬
nacle of philosophical eminence, if they had been applied with discretion.’
2 Works, ii., 162.
3 Works, iv., 119. In his Bakerian lecture (1806), he had said, “ In the present state of our knowledge, it would be useless
to attempt to speculate on the remote cause of the electrical energy, or the reason why different bodies, after being brought into
contact, should be found differently electrified; its relation to chemical affinity is, however, sufficiently evident. May it not
be identical with it, and an essential property of matter ?” — Works, vol. v., p. 39.
968
MATHEMATICAL AND PHYSICAL SCIENCE.
[Hiss. VI.
(763.)
Electro
chemical
theory—
Berzelius,
Hisinger—
Davy’s
first Bake-
rian lec¬
ture.
(764.)
Davy’s sa¬
gacious
inductions
1‘especting
polar
forces.
Electro-chemical Theory—Decomposition of the
Alcalies.—In 1804 Berzelius had published, in con¬
junction with Hisinger, a paper on Electro-chemical
Decompositions, in which he insisted on the general
fact, that alcalies, earths,and combustible bodies seem
to he attracted to the negative pole, and oxygen and
acids to the positive. He also showed that the sub¬
division of bodies thus obtained was only a relative
not an absolute one; for the same body may act
as a base to a second, and as an acid to a third.
But we must observe that results almost similar
were contained in the early papers of Davy, and
that Berzelius did not carry out his own principle
so far as to lead to any striking discovery between
1803 (when his experiments were made) and 1806
(the date of Davy’s first Bakerian lecture), during
which time the science of Galvanism or Voltaism
made little real progress. The numerous experi¬
menters engaged with it were baffled by the anoma¬
lous chemical results obtained, and by the appearance
of decompositions under circumstances wholly unex¬
pected, such as appeared to threaten the existence of
some of the best established chemical truths. The
chemical theory of the pile, at first so plausible, pre¬
sented new difficulties, and Berzelius having for a
while defended it, returned to the simple contact
theory of Volta. It was then that Davy seriously
addressed himself to the subject, resolved to trace
to their source every chemical anomaly ; and this
he effected in a masterly manner in his Bakerian lec¬
ture read before the lloyal Society in 1806. In it he
traces the unaccountable results of his predecessors to
impurities in the materials used by them, or to those of
the vessels in which the decompositions were made;
and he brings into a far distincter light than his pre¬
decessors had done, the power of the galvanic circuit
to suspend or reverse the action of even powerful
chemical affinity; “ different bodies naturally pos¬
sessed of chemical affinities appearing incapable of
combining or of remaining in combination when placed
in a state of electricity different from their natural
order.” We here see the fundamental doctrine of
the electro-chemical theory, that all bodies possess
a place in the great scale of natural electrical rela¬
tions to one another ; that chemical reactions are
intimately connected with this electric state, and are
suspended or reversed by its alteration.
In the interpretation of those striking experi¬
ments, in which he caused acids to pass to the posi¬
tive pole of the battery through the midst of alcaline
solutions, and the converse, we find so close an ap¬
proach to the theory of polar decomposition as enfor¬
ced by the discoveries and reasoning of Mr Faraday,
that it seems impossible to deny to Davy the merit
of having first perceived these curious relations.
“ It is very natural,” he says, “ to suppose that the
repellant and attractive energies are communicated
from one particle to another particle of the same kind
so as to establish a conducting chain in the fluid,
and that the locomotion takes place in consequence;”
and presently adds, “ there may possibly be a succes¬
sion of decompositions and recompositions through¬
out the fluid” (p. 29).1 He likewise shows (p. 21)
that the decomposing power does not reside in the
wire or pole, but may be extended indefinitively
through a fluid medium capable of conducting elec¬
tricity. Mr Faraday’s experiments, which led him to
discard the term pole, lead to the same conclusion,
and are of the same character. A few pages further
on in this same Bakerian lecture, Davy observes (p.
42), that “ allowing that combination depends on a
balance of the natural electrical energies of bodies,
it is easy to conceive that a measure may be found
of the artificial energies as to intensity and quantity
capable of destroying this equilibrium ; and such a
measure would enable us to make a scale of electrical
powers corresponding to degrees of affinity.” Here
we see the acute presentiment of the beautiful disco¬
very of the definiteness of electrical decompositions;
as in the concluding portion of the same remarkable
paper we find a clear anticipation of natural elec¬
trical currents to be discovered in mineral, and espe¬
cially metalliferous deposits, since established by
Mr It. W. Fox, and of the agency of feeble electric
energies, long continued, in effecting geological chan¬
ges, and in producing insoluble combinations of earths
and metals, so ingeniously confirmed by the beautiful
and direct experiments of Becquerel.
The sequel to this remarkable paper, read to the (765.)
lloyal Society in November 1807,contained the splen- Second Ba-
did application of the principle and methods which it
described, to the decomposition of the alcalies and to composi-
the discovery of their singular bases,—substances po- tion of the
sessing the lustre and malleability of metals, yet so alcalies*
light as to float upon water, and having the extraordi¬
nary property of becoming inflamed in contact with
ice. Potassium was discovered in the Laboratory of
the Royal Institution on the 6th October 1807, and
sodium a few days later. The battery used con¬
tained 250 pairs of plates of 6 and 4 inches square.
Such success was fitted to charm a disposition like
that of Davy, and more than reward him for all his
toils. To have discovered two new bodies, and
opened an entirely new field of wide chemical re¬
search, would itself have been enough. But the
extraordinary properties of the new bases were such
as seemed to correspond to the lively imagination
of the Chemist who produced them, and to transport
him to an Aladdin’s palace more brilliant than even
his fertile imagination had ever conceived. Yet it is
pleasing to remember that these popular discoveries
followed, at the interval of a year, the patient and t^insU-
able researches which led him to them, and which tute of
had already been rewarded, at a period of the bitter- France.
1 Of the Bakerian Lecture, in his collected Works.
Chap. VII., § 3.]
ELECTRICITY.—DAVY.
969
(766.)
Distin¬
guished
testimonies
to his
scientific
character.
est international hostilities, by the scientific prize of
3000 francs, founded by the Emperor Napoleon.1
The genius displayed in these, Davy’s most cele¬
brated researches, is evident on a careful perusal of
his papers; but still more from a consideration of the
state of science of the time, and of the willing tribute
to his merits paid by the ablest of his contempo¬
raries. Few persons of the present day will venture
to controvert the assertion of his acute contem-
(767.)
Chemical
researches
on chlo¬
rine and
iodine.
(768.)
Davy’s ex¬
tensive po¬
pularity,
and its
results.
porary, Dr Thomas Young (than whom no man was
ever a less indiscriminate eulogist), that Davy’s
researches were “ more splendidly successful than
any which have ever before illustrated the physical
sciences, in any of their departments and that the
contents of the Bakerian Lectures, in particular, “ are
as much superior to those of Newton’s Optics, as the
Principia are superior to these or any other human
work.” 2 A not less impartial tribute to his superla¬
tive genius has been yielded by M. Dumas, who, if I
mistake not, has described Davy as being the ablest
and most successful chemist who ever lived. A si¬
milar homage is paid to him by the sagacious Cuvier.
It is not within our scope to consider minutely
Davy’s purely chemical discoveries and experiments,
though they were numerous and important, indepen¬
dently of those made with the aid of electricity. His
proofs of the elementary nature of chlorine and iodine
were amongst the most considerable in their results.
But as a mere analyst, Davy had neither the leisure
nor the taste for continuous plodding labour, and
he therefore naturally made mistakes in chemical
details. His Elements of Chemical Philosophy re¬
mained, in consequence, a fragment of an exten¬
sive work. His contemporary, Berzelius, following
his steps in electro-chemical discovery, attained far
greater address, and became an author of high and
merited reputation, whilst his school surpassed all
others in Europe in producing accomplished analysts.3
The years immediately following the publication of
his Bakerian Lectures were passed by Davy in the
u envied possession of the highest fame, and in the
tranquil furtherance of his first and greatest disco-
vei’ies. His lectures at the Royal Institution con¬
tinued to be one of the most fashionable resorts in
jondon, and he was freely admitted in return into
he most aristocratic society ; he had but to express a
vish,and a voltaic battery of no less than 2000 pairs,
containing 128,000 square inches of surface, was con¬
structed for his use, by means of a liberal subscrip¬
tion. His health, when seriously compromised by
the severity of his labours, was a matter of public
concern, and its variations were announced by frequent
bulletins. The copyright of his lectures on agricul-
;ure wras sold for a price unexampled perhaps before
or since for such a work. In 1812 he was knighted
by the Prince Regent, and soon after he married a
lady of fortune and accomplishments. His duties at
the Royal Institution became thenceforth honorary.
He had in a space of ten years attained the pinnacle of
scientific reputation, and he was for the time truly
happy :—unenvious of others—deeply attached to
his relatives—generous of his resources—unwearied
in his philosophic labours. A certain change (it
must with regret be owned) came over his state of
mind, tarnished his serenity, and gradually though
imperceptibly weakened his scientific zeal. It was
to be ascribed solely, we believe, to the severe ordeal
of exuberant but heartless popularity which he un¬
derwent in London. The flatteries of fashionable
life acting on a young, ardent, and most susceptible
mind, mingling first with the graver applause of his
philosophic compeers, and at length, by their reitera¬
tion and seductions quite overpowering it, by degrees
attached Davy to the fashionable world, and loosened
his ties to that laboratory which had once been to him
the sole and fit scene of his triumphs. Had he been
blest with a family, his course would probably have
been evener and happier. Let us not severely criti¬
cise, where we still find so much to admire and to imi¬
tate. But we record the fact, for the consolation of
those who, beginning the pursuit of science, as Davy
did, in a humble sphere, and with pure ardour, may
fancy that they are worthy of pity, if they do not at¬
tain with him the honours of wealth and title, and the
homage, grateful to talent, of rank, wit, and beauty.
A research, second perhaps only to his electro- (769.)
chemical discoveries, remains to be noticed, as the Third pe-
chief fruit of the third period of his life, on which we of hls
now enter ; the first being his early career before
settling in London; the second, that passed in the
Royal Institution.
Researches on Flame—The Safety-Lamp.—The (770.)
subject was, the laws of combustion, and the happy Researches
invention of the safety-lamp. Though intimately
connected with the doctrine of simple heat, it may, lamp,
most properly, from its chemical character, and
from its connection with Davy’s history, be considered
briefly here. The lamentable loss of life occurring
in coal mines from explosions of fire-damp or inflam¬
mable air disengaged from the workings, had for
many years attracted the attention and sympathy of
the public, and had likewise been carefully considered
by scientific men. The explosive gas was known to
be the light carburetted hydrogen. Two plans alone
seemed to present themselves for diminishing the
danger:—the one to remove, or chemically to de¬
compose the fire-damp altogether ; the other, to pro¬
vide a miner’s lamp which, by its construction, should
Berzelius.
1 Such was the national feeling at this time in England, that worthy people were found who considered Davy as almost a
traitor, when he accepted the French prize. See Southey’s Life.
2 Quarterly Review, No. 15.
3 Jons Jacob Berzelius, the greatest analytical chemist of his day, was born in East Gothland, in the same year with Davy,
and died in 1848, when he had almost completed his 69th year. He contributed, in a signal manner, to the establishment of
Dalton’s principle of definite chemical equivalents ; but he made no single discovery of commanding importance.
VOL. I. 6 G
970
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(771.)
History of
the inven¬
tion of the
safety
lamp.
be incapable of causing explosion. The former of
these modes of protection, it was soon seen, could only
be palliative; the only efficient form which it took,
was that of a more effectual ventilation ; but the ter¬
rific rapidity with which a mine may be suddenly in¬
vaded by fire-damp, from channels opened by a single
blow of the pickaxe, must prevent it from ever act¬
ing as a cure. The latter plan had as yet yielded
nothing more effectual than the steel mill long used
by miners, which produced an uncertain and inter¬
mitting light, by the rotation of a steel wheel against
a flint, the scintillations of which were incapable of
inflaming the fire-damp. The insufficiency of the
light prevented it from being used, except in circum¬
stances of known danger. The celebrated Baron
Humboldt, Dr Clanny, and several others, had in¬
vented safety-lamps on different principles ; but they
were all clumsy and more or less ineffectual.1
At last, in the summer of 1815, the Rev. Dr
Gray (afterwards Bishop of Bristol), then chair¬
man of a committee appointed by a benevolent as¬
sociation at Bishop Wearmouth for the prevention of
colliery accidents, applied to Davy, who was then on
a sporting tour in Scotland, requesting his advice and
assistance. Sir Humphry answered the call with
promptitude. On his southward journey, in the
latter part of August, he visited the collieries, ascer¬
tained the circumstances of the danger which he had
to meet, and was provided by Mr Buddie with speci¬
mens of the inflammable air for examination. Within
a fortnight after his return to London, he had ascer¬
tained new and important qualities of the substance,
and had already four schemes on hand for the pre¬
vention of accident. Before the end of October, he
had arrived at the following principles of operation
in connection with a safety-lamp. “ First, A certain
mixture of azote and carbonic acid prevents the ex¬
plosion of the fire-damp, and this mixture is neces¬
sarily formed in the safe-lantern ; secondly, The fire¬
damp will not explode in tubes or feeders of a certain
small diameter. The ingress to, and egress of air from
my lantern,” he adds, “ is through such tubes or feed¬
ers ; and, therefore, when an explosion is artificially
made in the safe lantern, it does not communicate to
the external air.” The effect of narrow tubes in inter¬
cepting the passage of flame, is due to the cooling effect
of their metallic sides upon the combustible gases of
which flame is composed ;2 * and one of his first and
most important observations was the fortunate pecu¬
liarity that fire-damp, even when mixed with the
amount of air most favourable to combustion (1 part
of gas to 7 or 8 of air), requires an unusually high
temperature to induce combination. Olefiant gas,
carbonic oxide, and sulphuretted hydrogen, are all in¬
flamed by iron at a red heat, or ignited charcoal, but
carburetted hydrogen does not take fire under a per¬
fect white heat. The earliest safety-lamp consisted of
a lantern with horn or glass sides, in which a current
of air to supply the flame was admitted below by
numerous tubes of small diameter, or by narrow in¬
terstices between concentric tubes of some length ; or,
finally, by rows of parallel partitions of metal, form¬
ing rectangular canals extremely narrow in propor¬
tion to their length. A similar system of escape
apertures was applied at the top of the lantern.
With characteristic ingenuity, Davy did not stop Th<-7^2^t
here. He continued to reduce at once the apertures ianipS per-
and length of his metallic guards, until it occurred fected.
to him that wire gauze might, with equal effect, and
far more convenience, act upon the temperature of
flame, so as to reduce it below the point of ignition,
and thus effectually stop its communication. The ex¬
periment was successful, and by the 9th November
1815, or within about ten weeks after his first experi¬
ments, an account of the safety-lamp defended by wire
gauze was presented to the Royal Society. About two
months later he produced a lamp entirely enveloped
in metallic tissue.
There are none of Davy’s researches which (773.)
will stand a closer scrutiny than those which ter-
minated thus successfully. No fortuitous obser- for sjmiiar
vation led him to conceive a happy idea and to investiga-
apply it to practice. A great boon to humanity tlons•
and the arts was required at his hands ; and without
a moment’s delay, he proceeded to seek for it under
the guidance of a strictly experimental and induc¬
tive philosophy. Without, perhaps, a single false
turn, and scarcely a superfluous experiment, he pro¬
ceeded straight to his goal, guided by the prompt¬
ings of a happy genius aided by no common industry.
The chemical, the mechanical, and the purely physi¬
cal parts of the problem were all in turn dealt with,
and with equal sagacity. It may safely be affirmed
that he who was destitute of any one of these quali¬
fications must have failed in attaining the object so
ardently desired, unless by the aid of some rare good
fortune. We have it on Davy’s own authority, that
none of his discoveries gave him so much pleasure
as this one. His whole character possessed in it
much of a sympathizing and generous humanity;
his ideas of the dignity of science were from the first
(as his researches in Dr Beddoes’ laboratory showed)
intimately connected with the aim of advancing the
welfare, and of diminishing the misfortunes of man¬
kind : the rapidity and singular success of his inves¬
tigation in the case of the safety-lamp, kept his ardent
soul all alive, and afforded him the triumph of a Eu¬
reka at its completion. To these sources of inward
gratification was added the unstinted meed of praise
bestowed on him by his contemporaries. Playfair,
1 I have spoken in Art. 393 of the independent and ingenious efforts of George Stephenson t-nwirds the invention of a safety-
lamp contemporaneously with those of Davy.
2 This fact had been ascertained some years previously, by Mr Tennant and Dr'Wollaston, but it remained unpublished, and
was not applied by them to the prevention of colliery explosions.
(774.)
Rewards.
(775.)
Davy mo¬
difies La¬
voisier’s
theory of
combus¬
tion.
(776.)
Davy’s
protectors
for ships.
Chap. VII., § 3.] ELECTRICITY.—DAVY.
971
“ the true and amiahle philosopher,” as Davy long
before described him, thus proclaimed his victory in
the Edinburgh Review :—After describing the course
of a discovery “ which is in no degree the effect of ac¬
cident,” he adds, “this is exactly such a case as we
should choose to place before Bacon were he to re¬
visit the earth, in order to give him, in a small com¬
pass, an idea of the advancement which philosophy
has made since the time when he had pointed out to
her the route which she ought to pursue. The re¬
sult is as wonderful as it is important. An invisible
and impalpable barrier made effectual against a force
the most violent and irresistible in its operations;
and a power that in its tremendous effects seemed
to emulate the lightning and the earthquake, con¬
fined within a narrow space, and shut up in a net of
the most slender texture—are facts which must excite
a degree of wonder and astonishment, from which
neither ignorance nor wisdom can defend the be¬
holder.”
For this truly patriotic labour, the only national
testimony which Davy received was the inadequate
one of a baronetcy, which was conferred on him by
the Prince Regent in 1818; but his real triumph
and great reward were in the enthusiastic apprecia¬
tion of his entire success by those on whom he had
disinterestedly conferred so great a benefit. A tes¬
timonial, in the form of a service of plate, of great
value, was presented to him by the coal-owners of
the north of England.
Davy’s researches on flame were intimately
connected with his electrical and chemical discove¬
ries. He remodelled Lavoisier’s theory of combus¬
tion, and put an end to the distinction between com¬
bustibles and supporters of combustion. Chemical
combination, effected with great energy, and accom¬
panied by a high temperature, is essential to com¬
bustion, and either element of the combination is
equally entitled to the denomination of combustible.
Guided by the electro-chemical theory, Davy appears
to have thought that the heat of flame has an elec¬
trical origin.
But I must hasten to close this section. Among
the labours of his latter years, there was none which
interested Davy more, or which reasonably promised
more useful results, than his plan for protecting the
copper sheathing of ships from the corrosive action
of sea water, by affixing plates of zinc or iron, which
should render the copper slightly electro-negative, and
thus indispose it for combining with acid principles.
It is a somewhat singular fact that Fabbroni, about 30
years before, had instanced the corrosion of copper
sheathing near the contact of heterogeneous metals,
as an instance of the chemical origin of galvanism.1
Davy’s experiments were conducted with his usual
skill and success, and the remedy only failed of
general adoption on account, it may be said, of
being too effectual, other and opposite injurious
effects having been found to arise.
Davy was elected President of the Royal Society (777.)
in 1820, in the room of Sir Joseph Banks, who had
held the office for 42 years. It wras a distinguished 0f
compliment, for the election was all but unanimous. Royal So-
He continued to communicate papers for several his
years subsequently ; but his energy, his temper, and,
finally, his health began to give way—showing that
the ardent labours of his youth and prime had in¬
jured his constitution. Attacked with paralysis in
1827, he spent his last years chiefly abroad, and
died at Geneva (where he was buried), on the 29th
May 1829.
The character of Davy was a rare and admir- (778.)
able combination. The ardour of his researches, and Philosophi
the deep devotion of his whole being to scientific in- ^ charac_
vestigation, have been already proved. They had the
effect of completely annihilating every baser passion.
He valued property only in so far as he could apply
it usefully ; and his disinterestedness with respect to
the fortunes which several of his practical discoveries
might have honourably eaimed, wms one of the most
striking parts of his character. His fancy was dis¬
cursive to a degree rarely met with in men of science.
He continued to write poetry nearly all his life, and
the tone of it was that of grave speculation, always
reverting to the destiny of man and the beneficence
of the Creator. His lectures were composed with
care; and their effect, even as pieces of oratory, was
striking. Coleridge frequented them “ to increase
his stock of metaphors—yet they were always to
the point, and never degenerated into rhetorical dis¬
play. For a man of such extraordinary liveliness of
fancy and impetuosity of action, his mistakes were
astonishingly few. After his very first experience,
his publications were made with great care and judg¬
ment. His estimates of his contemporaries appear
generally to have been fair and liberal, though it
would be incorrect to affirm that he was universally
popular among them. The combination of isolated
and intense occupation in his laboratory, with ex¬
citement in the mixed society of an admiring London
public, was a trial which few, if any, could have
escaped better than he did ; and so far as we can
judge of a man from his expressed opinion of his
own successes, whether recorded in his works or in
his intimate correspondence, Davy must be accounted
to have acquitted himself gracefully and well. He
always spoke of the Pile of Yolta as the first source
of his own success. “ Nothing tends so much to the
advancement of knowledge as the application of a new
instrument,” he says; and then adds, “ The native
intellectual powers of men in different times are not
so much the causes of the different success of their
labours, as the peculiar nature of the means and
artificial resoui'ces in their possession a proposition
1 There appears, however, to have been something erroneous in the details of Fabbroni’s observations, or at least in the account
of them given in Nicholson/s Journal.
972
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
which he applies to his own discoveries. But we
may truly sjiy with one of his biographers, that to
him “ the Voltaic apparatus was the golden branch
by which he subdued the spirits that had opposed the
advance of previous philosophers; but what would
its possession have availed him had not his genius,
like the ancient sybil, pointed out its use and appli¬
cation?”
(779.) The last, and not least, extraordinary characteris-
Numerous ^jc 0f Davy to which I shall now advert, was the
practical p-^] ] practical turn of a mind which seemed formed
in a speculative mould. Four at least ot ms cmet
researches were of this kind—his experiments on
breathing the gases ; his lectures on agricultural
chemistry; his invention of the safety-lamp ; and
his protectors for ships. No man, whose path so
clearly lay in original discovery, ever left so many
valuable legacies to art and to his country.
(780.)
Divy’s as¬
sociates—
Young and
Wollaston.
(781.)
William
Hyde Wol¬
laston—his
contribu¬
tions to
Electricity,
(782.)
and the
other sci-
The name of Davy gave to England a distinguished
pre-eminence in science during the first 25 years of
the century. But two others, less noticed at the time,
ivere also among her worthiest sons. These were
Young and Wollaston. They were all three nearly
contemporaries ; all lived on good terms with one an¬
other, and united in promoting natural knowledge in
their several spheres. Young was Davy’s early,
though less successful colleague at the Royal Institu¬
tion ; and Wollaston wras joint-secretary with him
to the Royal Society. All three were originally
educated for the medical profession, and they all
abandoned it for the pursuit of science. Not the
least singular coincidence was in the periods of
their deaths, which all occurred within the space of
six months.
Our notice of Young, the first optical philosopher
of his age, belongs to another chapter. Wollaston,
though an original observer in nearly every branch
of exact science, considered himself as a chemist;
and his observations on Electricity were amongst his
first and best contributions to science. After the
impulse given to discovery by the invention of the
Pile, and the proof of the decomposition of water,
Wollaston undertook to compare critically the effects
of galvanic and frictional electricity—a task of some
nicety, and of very great importance at a time
when it could hardly be considered as certain that
these agents were not specifically different. By
methods peculiarly his own, he produced decomposi¬
tion, accompanied with separation of the elements at
the respective poles by means of common electricity.
He at the same time gave his powerful support to
the purely chemical theory of the Pile.
His most important inventions were rather in¬
struments which, in the hands of others, were to
produce important discoveries, than discoveries in
themselves. One was the invention of the Reflect¬
ing Goniometer for measuring the angles of crys¬
tals, now so essential to mineralogy; another, the
art of rendering platinum malleable, which has con¬
ferred inexpressible benefits on chemistry, and on the
arts connected with it. The principle of the reflec¬
tion of a ray of light for measuring angular spaces,
though it existed already in the single instance of the
sextant, has been, since it was applied to the gonio¬
meter, adapted to a multitude of most ingenious and
valuable contrivances.
Wollaston was an excellent optician, and of some (783.)
of his observations I have already spoken (476),
(538).
The strong points of his character were precision (784.)
and rare acuteness in observation, patience and cau- raster con-
tion in deduction, and habitual devotion of his time trasted
and energies to scientific pursuits. His foibles wrere with that
an excess of caution, and a certain microscopic turn of Davy-
of mind which, though it sometimes rewarded him
with valuable discoveries, consumed his time in oc¬
cupations of mechanical ingenuity, and prevented
him from grappling with almost any of the great
theories of his day. An exception, yet one which
illustrates his character, may be found in the fact
that he had all but anticipated Dalton in his disco¬
very of the multiple combinations of salts, whilst, with
his characteristic sense of justice, he disclaimed any
participation in the merit (624). While Davy was de¬
lighting crowded audiences with his eloquence, his
discoveries, and their wonderful results, Wollaston
was pursuing his solitary experiments on a scale so
small that scarcely three persons could witness them
at once. While Davy was firing his potassium with
ice, and making mimic volcanos heave by the oxida¬
tion of his new metals, Wollaston was extract¬
ing, by minute analyses, from the refractory and
unoxidable ores of platinum, substances previously
undetected, which, neither by their quantity nor
their characters, could ever interest any but a man
of science. While Davy was charging his prodi¬
gious battery of 2000 pairs,—the largest which
has ever been constructed (a homage to his ge¬
nius, provided by his numerous admirers),—Wol¬
laston was proving, after his fashion, how similar
effects could be produced by the very same agency
on a small scale ; and with no greater apparatus than
a shred of zinc, a few drops of acid, and an old thimble,
he would gratify his friends by exhibiting the mimic
glow of an almost microscopic wire of platinum.
Davy seemed born to believe; Wollaston to doubt.
Davy was a poet; Wollaston, a mathematician, or,
at least, capable of becoming a great one. Davy
announced his discoveries in fiery haste, and pre¬
sented all their consequences and corollaries as a free
gift to mankind ; Wollaston (estimating more truly
the rarity of the inventive faculty) hoarded every ob¬
servation, turned it over and over, polished it, ren¬
dered it exact beyond the reach of criticism, and
then deliberately laid it before the world. He had
the coldness and the accuracy of Cavendish, but he
wanted the spur of his genius, and the wide grasp
Chap. VII., § 4.] ELECTRICITY.—WOLLASTON—OERSTED—AMPERE. 973
of his apprehension. Among other legitimate re¬
sults of discovery, Wollaston was not unwilling to
claim for his own the material profits which such
researches sometimes, though rarely, yield ; whilst
Davy, as we have seen, spurned every possible attri¬
bution of an interested motive. Davy never made
a shilling in his life, save as an author or a lecturer
(except as paid assistant to Dr Beddoes) ; Wollaston
realized a fortune by his art of working platinum.
Davy was admired by thousands both at home and
abroad; Wollaston was little known except to a small
circle who could appreciate the resources of a mind
rarely opened in confidence to any one, and of which
the world was only partially informed.
Wollaston was born in 1766, and died in December (785.)
1828. The composure of his end rivalled that 0f1Ils death-
Black and Cavendish. His disorder was one of the
brain. When he had lost the power of speech, his
attendants remarked aloud that he appeared uncon¬
scious. Making a sign for a pencil and paper, he
wrote down a column of figures, added them up cor¬
rectly, and expired.
4. Oersted. — Ampere. — Discovery of Electro-Magnetism — Electro-Dynamic Theory —
Discovery of Thermo-Electricity ; Seebeck. The Galvanometer of Schweigger and Nobili.
(786.) Hans Christian Oersted was born in Langeland,
Oersted one of the Danish isles, on the 14th August 1777.
famousby ^ ^ might almost be said that “ on awaking
a single one morning he found himself famous.” The single
discovery, discovery of the mutual action of magnets and elec¬
tric conductors gave him a celebrity which a life-long
devotion to science has oftener than the contrary
failed to secure.
(787.) Yet in this, and perhaps every similar case, it will
be found that brilliant, and, as the world, or jealous
rivals esteem it, fortunate success, was not the result
of an isolated effort, but was connected with a long
career of patient though comparatively obscure la¬
bour.
(788 ) aSe 20- Oersted, whilst yet a student at
His early the University of Copenhagen, became an author,
studies. His first publication was a prize essay on an sesthe-
tical subject. Being intended for the medical pro¬
fession, he soon after wrote some chemical papers,
and, in 1801, his first “ On Galvanic Electricity.”
But his turn of mind at this time, as well as later,
was of a strongly metaphysical cast, and of course
tinctured with the peculiarities of the German
school as regards the study of physics, of which
the title of his thesis on graduation may be given
as an instance :—It was On the Architectonicks of
Natural Metaphysics. His studies in voltaic elec¬
tricity were made chiefly under Ritter, an obscure
and mystical writer, though the author of some cu¬
rious experiments on what were called Secondary
Piles ; and he at length obtained, in 1806, a pro¬
fessorship in his own university ; but his associates
appear to have been rather literary than scientific
persons, such as Steffens, Oehlenschlager, Niebuhr,
and Fichte ; he also engaged in controversies of a
theological tendency, which, to the end of his life,
appear to have had a great attraction for him.
(789.) In 1812 Oersted visited Berlin, and published
His first there a work on Chemical and Electrical forces, tend-
wmingson jngbj prove their identity, which was translated into
e ectricity, py ]y[arce} (je gerres. The author afterwards
looked back to the period of the publication of this
treatise as the dawn of his electro-magnetic discovery.
So far as I know of its contents (for I have never
seen a copy), it does not contain anything beyond
indefinite anticipations of the real identity of electri¬
city and magnetism. In this, indeed, there was no¬
thing new. Compass-needles had been seen to be
reversed by lightning ; electric shocks had been
passed through steel without any certain effect; and
Van Swinden had published a work in three volumes
expressly on the subject, containing the results of a
mass of ingenious failures. Nor, perhaps, can we
give Oersted credit, at that early period, for a more
distinct apprehension of the relation so anxiously
sought for, than was possessed by several of his con¬
temporaries. His belief is said to have been grounded
on the notion,that “if galvanism be only a hidden
form of electricity, then magnetism can only be elec¬
tricity in a still more hidden form”—a syllogism
which, if it satisfied Oersted’s metaphysical friends,
would hardly be accepted as demonstrative in the
laboratory ; and, after all, it suggests no one form of
relation rather than another.
Professor Forchhammer, the friend and pupil (790.)
of Oersted, states that, in 1818 and 1819, it was IIls disc0*
well known in Copenhagen that he was engaged eiYctro-
in a special study of the connection of magnetism magnetism,
and electricity. Yet we must ascribe it to a happy
impulse—the result, no doubt, of much anxious
thought—that, at a private lecture to a few advanced
students in the winter of 1819—20, he made the ob¬
servation, that a wire uniting the ends of a voltaic
battery in a state of activity, affected a magnet in
its vicinity. It was in the fact of the circuit being
closed, that the main difference consisted between this
and previous attempts, in which galvanic pairs or bat¬
teries not connected by conductors were expected to
show magnetical relations, though, in such a case,
the electricity was evidently stagnant.
Some mystery hangs over Oersted’s apprehension (791.)
of his own experiment. It seems difficult to believe Details re-
that he clearly saw its significance. Unlike Davy, sPect>ng it.
when he first saw the fiery drops of potassium flow
under the action of his battery, and recorded his
triumph in a few glowing words in his laboratory jour-
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
974
nal, Oersted took no immediate measures either to
complete or to publish his discovery. Some months
appear to have elapsed whilst waiting for the conve¬
nience of a larger battery before he repeated the ex¬
periment with the aid of Professor Esmark and other
friends. The battery then employed contained 20
twelve-inch elements, charged with water and ^th of
mixed nitric and sulphuric acids. The conducting
wire was heated red hot, which must have rather dimi¬
nished the effect than otherwise. The nature of the
wire was found to be unimportant. If positive electri¬
city passed from north to south through a conducting
wire placed horizontally in the magnetic meridian,
then a compass needle suspended over it had its north
end deviated to the west; if under it, to the east; if
the needle was placed on the east side of the conduc¬
tor, its north end was raised ; if on the west side, it
was depressed. Oersted further found that needles
of non-magnetic substances, such as brass and gum-
lac, were not affected, and that the electrical efficiency
depended on the quantity, not the intensity, of the
current. These experiments seem to have been made
in July 1820 ; and Oersted and his friends being now
fully alive to the novelty and importance of the dis¬
covery,he circulated extensively copies of a Latin tract,
dated the 21st July,in which the effects of the “electric
conflict,” as he terms the presumed combination of the
opposite electricities in the “ conjunctive wire” upon
a magnet, were described.1 In this tract we find the
following expressions :—“ The electric conflict acts
in a revolving manner.” “ It resembles a helix.”
“ The electric conflict is not confined to the conduct¬
ing wire, but it has around it a sphere of activity of
considerable extent.”
(792.) The effect of this pamphlet, consisting of a few
Speedily pages only, was instantaneous and wonderful. The
talcen up auth0r probably counted on the opportunity of devel-
pLe,m oping his discovery at leisure, but it was seized on
Arago, and with such avidity, and pursued with such signal suc-
^avy- cess, particularly in France, that he probably gave up
the race of invention in despair. Ampere had already
communicated experiments to the Institute on the
18th and 26 th September. Arago and Davy sepa¬
rately, and but little later, discovered the magnetiz¬
ing power which the voltaic conductor exerted on iron
filings, and the latter tried in vain the magnetizing
power of common or machine electricity, which, how¬
ever, was soon after shown by Arago, who enclosed
steel wires in helices of copper wire, through which
the discharges were passed. When soft iron was
placed in such a helix, it was found to become a tem¬
porary magnet of great power whilst the voltaic
cummt continued. Thus magnets of enormously
greater power than any previously known were con¬
structed ; one of the first large ones was made by Pro¬
fessor Henry of the United States.
(793.) Bed the progress of electro-magnetismas a science
was far more indebted to Ampere, a professor at
Paris, than to any other philosopher. I shall,
therefore, introduce here some account of his dis¬
coveries before closing what I have to say of Oer¬
sted.
Andre Marie Ampere was born in 1775 at Lyon. (794.)
He was an able mathematician, and wrote several Electro¬
memoirs on Chances, and on the Integration of Par- ^oryof
tial Differential Equations. But with this he com- Ampere,
bined a taste for, and a practical acquaintance with,
the experimental sciences. He was a very good che¬
mist, and showed himself particularly attentive to
Davy on his first visit to Paris. He was also much
attached to metaphysical speculation. His skill in
devising apparatus and in performing experiments was
eminently shown in his electro-magnetic researches ;
whilst he judiciously rendered his mathematical
knowledge subservient to them. In this respect he
had greatly the advantage of Oersted, who appears to
have been little acquainted with mathematics, and,
perhaps, in common with his metaphysical friends of
the German school, misapprehended their utility in
physical discoveries. Three different hypotheses Various
were speedily broached to represent mechanically °Pinion8
the singular kind of force mutually exerted between Mature
a conductor and a magnet. The first and most ob- 0f the elec-
vious was, that this action was not a ■push-and-pulltro-m&g-
force, but a force producing rotation without directnetic force•
attraction and repulsion, or of the nature of a couple
exerted between any part of an electric current, and
a small magnet or magnetic element. The second
opinion was, that an electric current may be esteemed
equivalent to a magnetizing force at right angles to
it. The third, that a magnet is composed of ele¬
ments which act as if a closed electric circuit ex¬
isted independently within each of them ; that is,
each magnetic molecule may be replaced by a small
conducting wire bent upon itself, in which some un¬
failing source of electricity, like a galvanic pair, keeps
up, in the same direction, a constant current.
This last hypothesis, arbitrary and improbable as (795.)
it may sound, was that defended by Ampere. Whilst Theory or
few will be disposed to regard it as a true and com- Adopted by
plete physical picture of the condition of magnetized Ampere,
bodies, it seems impossible not to award to it the same
sort of credit which we do to Newton’s “ fits of easy
reflection and transmission” of light, when we find
that it not only serves to represent the more obvious
phenomena, but has suggested experiments absolutely
new, and which turned out in accordance with the
anticipation ; and that, finally, by the sagacity and
industry of its author it was made to include, by
merely mathematical deductions, and without any
complication of the hypothesis, certain experiments
of a very singular kind, which at first seemed inex¬
plicable by it. I proceed to develope a little farther
this consideration.
1 The exact title was, Experimenta circa effectum Conflictus Electrici in Acum Magneticum.
Chap. VII., § 4.]
ELECTRICITY.—OERSTED—AMPERE.
975
(796.) The theory of Ampere rejects all hut push-and-
actionof forces’ such as are commonly recognized in ine-
electric chanical physics. These forces are mutual, and be-
conductors. long to electric currents. A permanent magnet is
a congeries of minute parallel and circular currents,
all acting in the same direction, which is at right
angles to the magnetic axis or line of force. Grant¬
ing this for a moment, Oersted’s experiment shows
that the current in the conductor acts on the currents
in the magnet; and as a magnet places itself trans¬
versely to a conductor, the currents in the magnet
tend to place themselves 'parallel to that in the con¬
ductor. Do we then find such properties in move¬
able electric conductors alone \ Have they any
mutual action ? Does that mutual action tend to
produce parallelism ? And if so, may it be farther
analysed into dii'ect attractions or repulsions of the
several parts of the electric currents upon one
another ? All these questions were answered by
Ampere affirmatively after due appeal to experiment.
Two copper wires connected with voltaic circuits,
and suspended with the requisite degree of freedom,
approach when the currents have a similar direction,
but are repelled when the direction is opposite in
the two. When two moveable conductors are placed
at right angles, or indeed at any angle, they tend to
parallelism. All the usual phenomena of a magnet
may be imitated by a long helix of copper wire
through which electricity is made by some artifice
continually to circulate. The position of the poles
is the same as in a real magnet, and the name of
pole is deteiunined by the direction (right or left
handed) in which the helix is wound. Such an in¬
strument, not containing one particle of iron, is at¬
tracted and repelled by a steel magnet,—obeys the
directive influence of the earth,—gives transverse
motion to an electric conductor near it,—in short,
does whatever magnetized iron does.
E/-0 Thus, in the mutual action of electric currents
tary kw of (for tne phenomena °f static electricity are wholly
the inverse unlike) we recognize the great discovery of Ampere,
square of A new science was formed, which he called electro-
tance 8* dynamics, which he proceeded to develope with great
skill and success. MM. Biot and Savary found that
the electro-magnetic force exerted by an indefinite
straight conductor and needle, varies inversely as the
simple distance from the conductor; but looking
to the elementary actions of each portion of the cur¬
rent, it will be found that this corresponds to the
usual physical law of the inverse square of the dis¬
tance between the magnetic and the electric ele¬
ment.
(798.) Whilst Ampere was pursuing his inquiries into
diyand^De^6 ProPer^es °f electric currents, others were vary-
la Hive— a great variety of ways, Oersted’s fundamental
Electro- experiment. A great number of beautiful mechani-
rotatiom ca^ arrangements were invented, particularly by the
a ions, ja ]qive an(j jyjr p,ara(Jayf The ]atter,
however, had the sole merit of effecting a most singu¬
lar kind of motion, that in which a magnet float¬
ing in mercury is made to revolve continuously
around a central conducting wire, and in like man¬
ner a conductor may be made to revolve round
a fixed magnet; nay, stranger still, a magnet
acting at once as conductor and magnet, revolves
with great velocity on its own axis when an elec¬
tric stream is made to traverse one half of its
length. These astonishing experiments, which, in
an earlier age, might have founded a new sect of
astronomers and replaced the theory of Vortices,
offered also considerable difficulties in the applica¬
tion of Ampere’s theory. They were, however, ulti-Accounted
mately removed by Ampere himself, who analysed
with great skill the mechanical conditions of each
case, and interpreting them into the language of his
theory, showed how continuous rotations might be
produced, according to the laws which he had esta¬
blished, by electric currents alone suitably arranged;
and he effected by most ingenious experimental combi¬
nations purely electro-dynamic rotations. Some other
experiments, in which magnets seemed to produce a
different effect from electro-dynamic cylinders, pre¬
sented a more serious obstacle, which, however, was
removed by a rigorous demonstration of the effects
which must ensue, if we regard the elementary mole¬
cules of a magnet as very small, and consequently the
entire magnet as a collection of indefinitely small and
correspondingly numerous electro-dynamic cylinders.
By means of four critical experiments, Ampere de¬
termined completely the elementary laws of the
mutual action of currents, including that previously
established by Biot and Savary in the case of a mag¬
net and a conductor. This investigation was one of
great intricacy, and was carried out with remarkable
skill. Ampere had the field almost to himself, Savary
making some contributions ; and, what is remarkable,
little or nothing has been added either to the theory,
or to the deductions from it, since his death. The
progress of the science of electro-magnetism has
been so astonishingly rapid since the year 1820, that
one set of phenomena after another has for the
time attracted almost exclusive notice. The disco¬
very of diamagnetism will probably lead to a recon¬
sideration of Ampere’s theory as applicable to all
matter in a more general form.
This rapid succession of interesting topics has pre- (799.)
vented attention from being perhaps sufficiently di-Great
rected to the importance of Ampere’s labours. jjemerit of
is at least as well entitled as any other philosopher 'T6116'
who has yet appeared, to be called “ the Newton of
Electricity.”
Ampere wras of an amiable, though rather eccentric (800.)
character. His absence of mind w^as proverbial, andIIls death
his style is somewhat cumbrous and obscure. But
he wTas devoted to science, the promotion of which
was ever his first consideration, and he evidently
himself possessed great clearness in his conceptions.
He died on the 17th Mav 1836.
976
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(801.) Whilst Ampere, Arago, Davy, the two De la
Seebeck. Rivegj and Mr Faraday, were throwing light on
ofthermo- the causes, and developing the consequences of
electricity. Oersted’s experiment, Seebeck of Berlin discovered
in 1822 a new source of electric excitement,
which has since become indirectly of very great im¬
portance. This was Thermo-Electricity. He found
that when heterogeneous metals are united, either
by soldering or pressure, and the junction heated, a
current of electricity is established. The order of
metals which produces the most energetic combina¬
tions, is wholly unlike the arrangement of the vol¬
taic series, and has no apparent reference to any
other known property of those substances. Bismuth
and antimony stand at the opposite extremities of
the scale, and a pair formed of them is consequently
the most powerful which can be made. When heat¬
ed at the junction, positive electricity passes from
bismuth to antimony. In 1823, Oersted, then on
a visit to Paris, united with Fourier in making
expex-iments on this subject, and was probably the
first who constructed thermo-electrical piles. Un¬
questionably, the most important application of these
was to the construction of an instrument for measur¬
ing the effects of radiant heat, by Nobili and Melloni,
of which an account has already been given, Art.
(709).
(802.) An application of electro-magnetism of extreme
Invention importance, was the Multiplier or Galvanometer,
galvan- contrived by Schweigger of Halle. In it the idea
ometer— was first realized of measuring the power of an
Schweig- electric current by its effect in deviating a mag¬
netic needle. Schweigger perceived that he could
multiply the action of one and the same current, by
causing it to traverse successive parallel coils of the
conducting wire carried round the needle. Its sensibi¬
lity was still farther, and almost indefinitely increased
byNobili’s invention of rendering the needle asiaZic, or
diminishing its natural directive power in any required
degree. This he did by connecting it firmly with a
second needle parallel to the first, of nearly equal
strength, with its poles placed in an inverted posi¬
tion relatively to the other, and moving freely in a
plane altogether exterior to the coil, so that whilst
the directive effect of the earth’s polarity is almost
neutralized, the electro-magnetic effect of the coil
tends to produce a similar deviation in both needles.
This is one of the most precious philosophical instru¬
ments ever invented. It has been employed for
thirty years in almost every electrical research or
application. One of its best forms for many pur¬
poses (though hitherto little used) is the Torsion
Galvanometer of Bitchie.
Oersted, of course, interested himself in this new
Oersted’s application of his own great discovex-y. Indeed, hav-
continued ^ie g00^ fortune to survive that discovery for
more than thirty years, with a full enjoyment
of his intellectual vigour, he had the gratifica¬
tion of contemplating a body of science entirely
ger ana
Nobili.
(803.)
new as its results, and a variety of useful ap¬
plications scarcely less astonishing, which might,
in one sense, be called his own creation. The dis¬
coveries of Ampere, Seebeck, and Mr Faraday, were
all based upon his; and dui'ing those thii-ty years, this
elegant and interesting branch of experimental phy¬
sics underwent an almost uninterrupted extension,
such as hardly any other affords an example of. The
Electric Telegraph is one of its most direct and practi¬
cal results ; nor should we omit that Oersted himself
proposed, as far back as 1818, the application of elec¬
tricity to blasting rocks by the very same process in
which it has of late years been so usefully applied,
namely, that of heating a fine wire to incandescence.
Though Oersted was the author of numerous (804.)
papers connected with science down nearly to His experi-
the close of his life, they do not contain any impor- ments on
tant discovery, and with reference to electro-mag- passion 0f
netism, he appears to have contented himself princi- water,
pally with repeating and expounding the observations
of his contemporaries. But some of his experiments on
other subjects deserve mention, especially those on the
compressibility of water. This fact, which the Flo¬
rentine Academicians had vainly sought to establish
in the 17th century, had been clearly demonstrated
by Canton in the middle of the 18th, but Oersted
first devised a compendious and effective apparatus
for producing and measuring it more effectually. His
result, that the compression amounts to 46-millionths
of the bulk, for a pressure equal to one atmosphere,
agrees almost precisely with Canton’s. In 1845, he
considered that he had established that the heat de¬
veloped by the same amount of compression is ‘0203
of a centigrade degree. He also made some experi¬
ments on the Law of the Compressibility of Air and
upon other subjects.
The desideratum of a clear expression of the mani- (805.)
fest alliance between Electricity and Magnetism had °®rste(l re-
been so long and so universally felt, that the discovery prize 0f
placed its author in the first rank of scientific men. the Insti-
There was not even, so far as I am aware, a sus- tute of
• rranee
picion that he had been, however remotely or dimly,
anticipated. The prize of the French Institute which
had been awarded to Davy for his galvanic discoveries,
was bestowed upon Oersted, and so far as I am inform¬
ed, has not been since adjudicated. He was elected first
Correspondent, and finally Associate of the Academy
of Sciences. He was personally known to many of
the philosophers of Europe, having made repeated
journeys in France, Germany, and England. His His scien-
agreeable manners and general information rendered tificcharac‘
him popular. Sir H. Davy, who visited him at Co- ter*
penhagen, describes him as “ a man of simple man¬
ners, of no pretensions, and not of extensive re¬
sources.” Niebuhr, however, who viewed his cha¬
racter in a different light, says, “ I scarcely know
another natural philosopher with so much intellect,
and freedom from prejudice and esprit de corps” His
writings were indeed too discursive. Professor Forch-
Chap. VII., § 5.] ELECTRICITY.—OERSTED—DR FARADAY. 977
hammer has enumerated above 200 of his publica¬
tions or articles, on a vast variety of subjects ; but
of all these, only a single tract of a few pages will
perhaps be ultimately remembered. As I before
remarked, his mind, though capable of continued
application, appears to have wanted the sort of con¬
centration which prolonged physical researches re¬
quire, and the school of philosophy in which he was
considered by his own countrymen as a proficient, has
never been fruitful .in researches based on Induc¬
tion.
In November 1850, the fiftieth anniversary of his (806.)
connection with the University of Copenhagen was ^is death.
celebrated by a jubilee. Though in his 74th year,
his activity was unimpaired, and he continued his
lectures and other employments until within a few
days of his death, which occurred on the 9th of March
1851, closing a life full of years and honour.
§ 5. Dr Faraday.—Progress of the Theory of Electro-Chemical Decomposition—Volta-Electric
Induction—Magneto-Electricity—Diamagnetism—Optical Changes induced by Magnetism.—
Professor Pliicker—Magneoptic Action.
(807.) Immeasurably the larger part of what we know
diTcOTTries with regard to tlie nature and laws of electricity and
ofSDrFara- connection with Magnetism, so far as it has been
day. developed since the discovery of Oersted, is due to
the genius and perseverance of one man—Michael
Faraday.
(808.) This eminent philosopher was born, I believe, in
hlstor^a/nd -l^e was originally “ a bookseller’s apprentice,
connection —ver7 fond of experiment and very averse to trade.”
with Davy In 1812 he sent to 'Sir H. Davy, then at the height
and the^ of his reputation, a copy of a set of notes taken at his
stitution” loci'111,68* desiring his assistance “ to escape from trade,
and enter into the service of science.” To the credit of
the popular and distinguished chemist, he gave Mr
Faraday a courteous answer, and appointed him as
chemical assistant in the Laboratory of the Royal In¬
stitution in March 1813. Leaving England to travel
in the autumn of the same year, Davy engaged Mr
Faraday to accompany him as secretary and scien¬
tific assistant; they returned in April 1815, and
from that time to the present Mr Faraday has
been constantly engaged in the scientific business
of the Royal Institution, which is as completely
associated with his numerous and splendid dis¬
coveries as Cambridge is with those of Newton,
and Slough with those of the elder Herschel. By
a rare, perhaps unexampled good fortune, that esta¬
blishment, founded principally for the promotion
of original research and the promulgation of dis¬
coveries, has been indebted during the first fifty
years of its existence to the talents of two men only,
for a succession of new scientific truths which might
have done credit to a whole academy; indeed, if
to the names of Davy and Mr Faraday we add
that of Young, who here first promulgated the doc¬
trines of the Interference of Light, there is scarcely
an academy in Europe which has within the same
period added so extensively to our choicest stock of
original science.
(809.) Partly in consequence of his official duty of bring-
Vanety of ing forward and explaining the most important cotem-
cations  porary discoveries, partly also m consequence of his
his Re- own matchless talent of elucidating, by original illus-
searchet on trations, if not by new facts, whatever he undertakes
Electricity. v
to expound, the variety of subjects on which Dr Fara¬
day has made essential additions to our knowledge
is so great that it is difficult to comprehend them
under one section. In conformity, however, with our
plan of suppressing minor facts, and insisting on the
most important, I shall confine myself to a summary
statement of his main discoveries connected with
Electricity and Electro-Magnetism as contained in a
continuous series of “ Researches,” published in the
Philosophical Transactions between 1831 and the
present time; which, when collected (as they have
been in a distinct form), now fill three closely
printed octavo volumes. It would be difficult to
name in the history of any progressive experimental
subject so large an amount of research prosecuted
for so long a time in so methodical a manner and
with such remarkable uniformity in plan, and with
such unvarying success.
I shall only farther premise that Dr Faraday’s (810.)
earliest essays were naturally of a chemical charac- JElectro-
ter. In 1820 he assisted Davy, in prosecuting Oer-mil;g°etlc
sted’s researches on the relations of Electricity and
Magnetism, and the following year he himself suc¬
ceeded in producing, for the first time, the continuous
rotation of a magnet round an electric conductor, and
the converse rotation of the conductor round the
magnet (798). These experiments were the germ
of others which continued to interest philosophers as
well as the curious public for a long time after. But
it was in 1831 (when the author had attained his 40th
year) that, the genius of Dr Faraday was displayed
in a commanding manner by the appearance of his
First and Second series of the Researches on Electri¬
city, which have not perhaps been surpassed by even
the most brilliant of their successors. The subject was
the Induction of Electric Currents from other Currents
and from Magnets. But we shall find it most con¬
venient to take an order different from that of the
discovery, and to present the main results of Dr
Faraday’s electrical labours under the following jiea(js 0f
heads:— his chief
I. The law of definite Electro-chemical Decompo- electrical
sition, and the theory of the pile connected therewith, netica]8 dis-
II. The Induction of Electric Currents from other coveries.
6 H
(811.)
Electro¬
chemical
decomposi¬
tion, and
theory of
the pile.
Definite
character
of decom¬
position—
electrical
equiva¬
lents.
(812.)
Inferences
as to the
identity of
electrical
and chemi¬
cal forces.
978 MATHEMATICAL AND PHYSICAL SCIENCE. [Diss. VI.
Currents and from Magnets, or the discovery of
Magneto-Electricity.
III. The influence of the Magnet on all bodies,
and the consequent division of substances into two
classes, Magnetics and Diamagnetics.
IV. Optical changes induced by Magnetism.
I 'With regard to electro-chemical decomposition
and the theory of the pile, the great extent and intri¬
cacy of the subject require us to restrict our analysis
to a few of the leading conclusions. The most im¬
portant of these may be summed up in the following
propositions :—1st, The amount of a decomposable
substance (or electrolyte) analysed into its elements
by a current of electricity depends solely on the
amount of electricity passing through it, and is in¬
dependent of the form of apparatus employed, the
dimensions of the poles (or electrodes), the strength
of the solution, or any other circumstance. It is
thence inferred, with respect, for instance, to water,
that the amount of it decomposed in a given time is
an exact measure of the quantity of electricity set in
motion in that time. 2<i, When a substance is thus
decomposed, it is a necessary, or at least a highly
probable, consequence of Dalton’s laws, that the
elements separated are in atomic proportions to one
another. But Mr Faraday also found that when
several decompositions are effected at the same time
by interposing different electrolytes in intervals of
the same circuit, the whole of the series of elements
separated bear the atomic relations to one another.
Thus, to take a single case ; an electric current de¬
composes in the same time 0497 grain of water
and 3*2 grains of protochloride of tin. Now, these
are exactly the proportions of the atomic weights of
those bodies. From this and numerous other cases
Mr Faraday infers, that universally the amount of
electrical action required to dissolve a combination is
in a constant proportion to the force of chemical affi¬
nity by which its elements are united. The corollary
seems therefore highly probable that it is one and the
same force which is exerted in either case. But the
conclusion as to their identity becomes almost irre¬
sistible when we add to these propositions the follow¬
ing: Sdly, That the oxidation of one atom of zinc by
the acid of the battery generates precisely so much
electricity as would resolve one atom of water into
its elements. Thus, 8*45 grains of zinc dissolved
occasioned the analysis of 2-35 grains of water ; but
these numbers are in the ratio of 32-5 to 9 ; the
equivalents or atomic weights of zinc and water.
From these strictly experimental laws, Dr Fara¬
day considers that he is entitled to draw these im¬
portant inferences : First, that the source of voltaic
electricity in the pile is chemical action solely;
Secondly, that “the forces termed chemical affinity
and electricity are one and the same.”1 Itis needless to
add that these conclusions, involving the very essence
of the science of voltaic electricity, are supported by
Mr Faraday by a great variety of collateral proofs ;
and, on the whole, I cannot see that they admit of any
reasonable doubt. The contact theory of Volta still,
however, holds its ground in Germany, where the
number of influential writers on electricity is con¬
siderable ; and so perseveringly is it maintained, that
it is difficult to perceive how it is ever to be dis¬
lodged. But on this wide and not very profitable
controversy we cannot here enter.
There are a great many other considerations (813.)
connected with the action of the voltaic batteryDr Fara-
which are independent of these primary ones, and Auction111
which are scarcely less important. Dr Faraday and Con-
has entered into a most elaborate experimental Auction,
argument to show that induction always precedes
both conduction and decomposition, and that de¬
composable bodies or electrolytes must be all more
or less perfect conductors. His views may be thus
concisely summed up in his own words :—“ The first
effect” of the electrifying influence, whether of fric¬
tional electricity or of voltaic electricity, upon bodies,
is “ the production of a polarized state of their par¬
ticles which constitutes induction ; and this arises
from its action upon the particles in immediate con¬
tact with” the excited body, “ which again act upon
those contiguous to them, and thus forces are trans¬
ferred to a distance. If the induction remain un¬
diminished, perfect insulation is the consequence;
if the contiguous particles” thus polarized “ have
the power to communicate their forces, then con¬
duction occurs, conduction being a distinct act ot
discharge between neighbouring particles.” “ In the
inductive condition assumed by water” when about
to be decomposed, “ the discharge between particle
and particle is not, as before, a mere interchange of
their powers and forces, but an actual separation of
them, the oxygen travelling in one direction and
carrying with it its amount of force acquired during
polarization, and the hydrogen doing the same thing
in the other direction, until they each meet the next
approaching particle, which is in the same electrical
state with that they have left, and by association of
their forces with it produce discharge. This action
may be regarded as a carrying one performed by the
constituent particles of the dielectric.”2 Again,
“ the current is an indivisible thing ; an axis of
power, in every part of which both electric forces are
present in equal amount.1’3
These views respecting the molecular progress of (814.)
conduction and decomposition, though perhaps never
so categorically stated as by Dr Faraday, have been,
I imagine, substantially held by a majority of those
who have considered the subject since the time
of Davy, who first gave them a partial expression.
And when Davy and others speak of the electric
forces in decomposition as if they emanated from the
1 Researches, Art. 918.
2 lb., Arts. 1338, 1347.
3 lb., Art. 1642.
Chap. VII., § 5.]
ELECTRICITY.—DR FARADAY.
979
(815.)
Uniform
nature of
electricity
from what¬
ever source.
(816.)
Induction
of electric
currents—
magneto¬
electricity.
poles of the battery and became enfeebled with dis¬
tance from them, they used a language not quite
rigorous indeed, yet expressing the actual pheno¬
mena with that general accuracy which we can alone
expect in the first stages of so new and difficult an
inquiry. “ The sum of chemical decomposition is
constant for any section of a decomposing conductor”
is Dr Faraday’s expression.1 So is the sum of illumi¬
nations arising from light radiating from a point,
when taken across any section of its path, yet the
influence is said to vary inversely as the square of
its distance from the origin. The part of Dr Fara¬
day’s conclusions, however, most open to excep¬
tion, is what refers to electric action at a distance,
which he conceives to depend solely upon induction
acting on intervening particles, which induction may
take place along curved lines. It is indeed true that
he has shown, by a beautiful experiment, that the in¬
terposition of different substances between an excited
electric and a body capable of being electrified by in¬
duction, occasions different degrees of excitement in
the latter, even when the interposed bodies are glass,
sulphur, and other “ non-conductors and this he
justly refers to a peculiar power or property of bodies
called “specific inductive capacity.” But this is
rather different from the general proposition above
referred to.
In conclusion of this part of the subject, I must
add that Mr Faraday has, with great pains and suc¬
cess, demonstrated the fundamentally identical nature
of electricity from whatever source derived, and how¬
ever differing in its usual manifestations;—such as
electricity of the pile, of the common machine, or that
induced by magnetic, thei’mal, and animal electricity.
These have all common properties, producingthe shock,
the spark, and magnetic, chemical, and heating effects;
and, except two, also producing sensible attraction
and repulsion. But the disproportion of the effects
of electricity, varying so much in intensity when re¬
ferred to unit of quantity, is astonishing and para¬
doxical. The electricity which so silently and speedily
decomposes a single grain of water would, when its
intensity is sufficiently exalted, produce, according to
Mr Faraday, “ a very powerful flash of lightning,”
or 800,000 times the contents of a well charged Ley¬
den battery. Again, zinc and platinum wires half an
inch long and one-eighteenth inch diameter, dipped
into slightly acidulated water, produce in three se¬
conds as much electricity as a man can easily bear
in the form of a shock.
II. Induction of electric currents from other cur¬
rents and from magnets.—This splendid research,
which dates from 1831, constitutes the discovery of
magneto-electricity.
The discovery by Ampere of the attraction and
repulsion of conductors conveying electric currents
rapidly followed (as we have seen in Art. 796) Oer¬
sted’s discovery of the power of electricity to affect
the magnet, and the corollary from it of the mag¬
netizing agency of electricity. This being achieved,
very striking analogies led to the expectations—1.
That a wire conveying a current ought to excite by
induction a current in another wire near it; and, 2.
That a magnet ought, under some circumstances at
least, to be capable of exciting electric action. But
attempts in these directions had repeatedly and sig¬
nally failed, and for a reason which Mr Faraday first
rendered apparent.
Having made a compound helix of two copper (817.)
wires wound parallel to one another, but not touch- ^?lt.a'®lec‘
ing, and rolled one within the other upon a cyan- tion.
der, he found that when he transmitted a continu¬
ous voltaic current through one wire, a momen¬
tary current (tested by a galvanometer) took place
in the independent helix in the same direction with
the primary current^; but it ceased to exist in¬
stantaneously, although the primary current conti¬
nued to act; and it was only on the cessation of
that current that a new momentary induced current
appeared, but in the contrary direction to the previ¬
ous one. The same effect occurred when a wire
conducting a current was mechanically brought into
the presence of another wire ; the approximation of
the two induced a similarly directed current, their
separation a contrary effect. Whilst the wires were
immovable no induced current took place. This
he termed Volta-Electric Induction.
Mr Faraday next took a ring of soft iron, disposing (818.)
two copper-wire coils round opposite portions of the
ring. In passing a current through one coil, and
thus magnetizing the ring, a current was induced in
the other copper coil, but, as in the former case, only
for an instant. When the primary current stopped,
and the magnet was unmade, an opposite current
shot through the secondary coil.
The transition to the next experiment was natu- (819.)
ral, but highly important. The primary coil was Magneto-
suppressed ; and the piece of soft iron embraced by electriclty*
the secondary coil was now magnetized by the in¬
ductive action of a powerful bar magnet, with
which contact was alternately made and broken.
At the instant of making contact a momentary
current of electricity was produced in the remain¬
ing coil, and on breaking it a reversed current,
also of instantaneous duration. No current ex¬
isted whilst the magnet continued to be applied.
The direction of the current at making contact
was opposite to that which would have produced
the magnetism present in the iron core; on break¬
ing contact the current was similar to that which
would have magnetized the iron. The electricity
momentarily induced in the coil was tested by its
action on the galvanometer, by its power to mag¬
netize steel, to convulse a frog, and finally by the
1 Researches, Art. 504.
980
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(820.)
(821.)
Arago’s
rotation-
magnet¬
ism ex¬
plained.
(822.)
(823.)
Dr Fara¬
day’s dis¬
covery of
diamag¬
netism.
Classifica¬
tion of
magnetic
and dia¬
magnetic
bodies.
production of a spark. This, then, was the disco¬
very of magneto-electricity.
The mere motion of a permanent magnet was now
substituted for the induction of magnetism in soft
iron. By pushing one end of a bar-magnet into the
coil, electricity was developed so long as the motion
continued; on withdrawing it an opposite cunent
took place. Even the feeble magnetism of the
earth induced a sensible electric current in a wire
moved transversely to the direction of the dipping-
needle.
By making a copper plate revolve in the neigh¬
bourhood of a powerful magnet, a continuous cur¬
rent of electricity may be detected passing from the
centre to the circumference of the plate, and may be
collected by proper means. Here, then, is a mag¬
neto-electric machine. This current perpetually pre¬
sent in a conducting plate revolving beneath a mag¬
net, cannot fail (by the common laws of electro¬
magnetism) to react on that magnet. Dr Faraday
showed in the most satisfactory manner that its
action is exactly what is required to explain M.
Arago’s experiment of “ transient magnetism by
rotation” — namely, to cause the magnet (if free)
to follow the direction of motion of the plate
(515).
On the whole, this research of Dr Faraday may be
cited as one of the most original and admirably
conducted which the annals of science present,
and as such may be usefully recommended to the
student.
III. The influence of the magnet on all bodies, and
their consequent division into two classes ; Magnetics
and Diamagnetics.—By many, perhaps most persons,
this will be regarded as the greatest of Dr Faraday’s
discoveries. It dates from 1846. By using electro¬
magnets of very great power, and suspending bodies
of a somewhat elongated form between the poles, he
has proved that every substance, solid, liquid, or
gaseous which he has put to the test, is either drawn
into a line joining the poles of the magnet, as soft
iron would be, returning to that line if displaced, or
else it settles in a position at right angles to this, or
across the line of poles. The former he calls para¬
magnetic or simply magnetic bodies, and their posi¬
tion axial; the latter diamagnetic bodies, and their
position equatoreal. Bodies may be arranged in a
list commencing with those most paramagnetic, dimi¬
nishing to neutrality, then feebly diamagnetic, and
finally the strongest diamagnetics. The following
is such a list of a few solid and liquid bodies thus
classified:—
Magnetics or Paramagnetics.
Zero
/iron.
/ Nickel.
I Cobalt.
I Manganese.
1 Palladium.
Crown glass.
Platinum.
(Osmium.
..Vacuum.
Diamagnetics
Arsenic.
Ether.
Alcohol.
Gold.
Water.
Mercury.
Flint glass.
Tin.
“ Heavy glass.”
Antimony.
Phosphorus.
, Bismuth.
The equatoreal pointing of diamagnetic bodies evi- (824.)
dently presupposes that they are longer in one di- ^ne<^®.n_'
mension than in the others. A small bar of sili- inent and
cated borate of lead, or “ heavy glass,” about two definition
inches long, and from a quarter to half an inch of diamag-
broad and deep, suspended m a stirrup ot paper by
six or eight lengths of cocoon silk, was the appa¬
ratus first employed by Dr Faraday. When a
sphere or a cube is used, of course it cannot point.
The diamagnetic action is shown in that case by the
little body being repelled indifferently from either
pole of the magnet, in the same manner as soft iron
is indifferently attracted by either. This repulsive
tendency includes the phenomenon of equatoreal
pointing, and its law is thus comprehensively ex¬
pressed : “ The diamagnetic tendency is to move the
body from stronger to weaker places of magnetic
force.”
The behaviour of diamagnetics in the presence of
a magnet may be thus further illustrated. It is inustra_
what would occur if a body absolutely inert weretions.
suspended in a fluid pressing upon it. that fluid
being at the same time more or less magnetic, that
is, more or less attracted by either pole of the mag¬
net. The result would evidently be, that the body
would seem to be repelled, and would set equato-
really for the same reason that a piece of wood
plunged in water rises to the surface as if repelled
by gravity. Thus Dr Faraday suspended feebly
paramagnetic bodies in ferruginous solutions more
magnetic than themselves, when they acted as dia¬
magnetic bodies would do.
It is impossible for the most part to guess before- (826.)
hand to which class a substance will belong. China-
ink, porcelain, silkworm gut, shell-lac, and charcoal,
rank amongst paramagnetic substances ; whilst sul¬
phur, resin, wood, leather, and most animal sub¬
stances, are diamagnetic. Thus, if a living man
could be delicately enough suspended between the
poles of a huge magnet, he would settle equato-
really.
Philosophers are not yet entirely agreed as to the (827.)
precise nature of the Diamagnetic relatively to the "10n
Magnetic actions of bodies. Besides Dr Faraday, natUre of
MM Weber and Edmond Becquerel abroad, and Pro- diamagnet
fessors Tyndall and William Thomson in this coun- *sm'
try, have examined the subject both practically and
theoretically in great detail. The more probable
opinion seems to be, that bismuth and its analogues
Chap. VII., § 5.]
ELECTRICITY.—DE FARADAY—M. PLUCKER.
981
(828.)
Obscure
anticipa-
by Brug-
mans and
Lebaillif.
(829.)
Father
Bancalari
discovers
the dia¬
magnetism
of flames.
(830.)
Dr Fara¬
day on the
magnetism
of oxygen.
(831.)
Professor
Pliicker on
magne-
optic force,
acquire a true polar condition under the action of
magnets, hut opposed to that which iron and para-
magnetics do in Jike circumstances.
Like almost every other great discovery, some
feeble traces of this may be found amongst the vo¬
luminous records of almost forgotten experiments.
Brugmans observed, in 1778, the repulsion of bis¬
muth by a magnet, which was rediscovered by Le¬
baillif in 1827 ; and something like the equatoreal
pointing of shell-lac and wood was noticed in the
same year by Becquerel, and may also be traced in
the writings of Coulomb. The present writer recol¬
lects very distinctly to have had pointed out to him
by M. Becquerel, at Paris, about 1835, the pointing
of minute chips of wood placed near a common steel
magnet. But these incidental facts having been suf¬
fered to remain in complete obscurity for so many
years, without even an attempt to connect and ex¬
plain them, can scarcely be said even to touch the
originality of Dr Faraday’s discovery.
The year after the announcement of diamagnet¬
ism, Father Bancalari of Genoa discovered the
powerful diamagnetic quality of flame. It is easily
shown by placing the flame of a wax taper between
two blunt conical terminations of a powerful electro¬
magnet. The flame spreads equatoreally, becoming
flsh-tailed. Dr Faraday, zealously taking up the in¬
quiry, proved that this depends upon hot air being
diamagnetic relatively to the surrounding cold air,
but that atmospheric air is always absolutely para¬
magnetic. Analyzing the effect still farther, he
found that the oxygen of the air is a very powerful
paramagnetic, whilst nitrogen is relatively diamag¬
netic, but in all probability is a neutral substance,
one at the real zero of this singular scale. By a most
ingenious application of the torsion balance, he was
enabled to compare the relative actions of magnet¬
ism on the gases with admirable skill and precision.
(Philosophical Transactions, 1851.)
These experiments demonstrate a paramagnetic
(or iron - like) attraction in oxygen really aston¬
ishing. A small mass of oxygen appears to be
attracted at the distance of an inch from the axial
line of the electro-magnet by a force equal to
its own weight! Since heat diminishes this qua¬
lity, the acute perception of Dr Faraday rapidly en¬
tertained the idea that the apparent magnetism of
the earth might partly at least reside in the atmo¬
sphere, and that the changes of terrestrial magnetic
intensity and direction might be explained by the
action of the sun expanding the atmosphere. The
26th series of his researches is devoted to an elabo¬
rate exposition of this theory, which, however inge¬
nious, is still involved in great difficulty.
Professor Plilcker—Attraction and Repulsion of
Optic Axis of Crystals.—Soon after Dr Faraday’s dis¬
covery of diamagnetism, Professor Pliicker, of Bonn,
announced the important fact, that tbe optic axis of
Iceland spar is repelled by the magnet. A sphere
rm • crystallic
11118 force.
(833.)
of that substance suspended by a thread, and having
its axis horizontal, being placed between the poles,
notwithstanding the perfect symmetry of external
figure, the axis ranges itself in the equatoreal position.
In some other crystals the axis is directed in the
line of poles. The law of the phenomena is not yet
completely made out; but so strong is the latter qua¬
lity in crystals of kyanite, that a piece of that sub¬
stance properly suspended will actually show a direc¬
tive power under the influence of the earth’s mag¬
netism.
Probably closely allied to this fact is a similar (832.)
directive tendency observed in well crystallized spe- Magne-
cimens of bismuth, antimony, and arsenic.
M. Pliicker calls the magne-crystallic, as the for¬
mer may be termed the magne-optic force ; and
it is often so intense as to oppose and even reverse
the directive tendency which the body would have
had between the poles in its massive or uncrystal¬
lized state.
It will be easily conceived that the interest crea¬
ted by these admirable discoveries, revealing not only
new and general properties of matter, but also rela¬
tions between very different branches of science, soon
became general, and raised the reputation of Dr
Faraday to the very highest rank as an experimental
philosopher. If we compare his two greatest works,
that on magneto-electricity, and this on diamag¬
netism, wre find in the former perhaps a more perfect
specimen of inductive sequences ; in the latter, facts
more independently novel and unlooked-for, and an
unrivalled skill in the application and invention of
experimental methods.
Passing over many less important matters, there (834.)
yet remains one interesting discovery to be men- Dr Fara-
tioned, which in point of time preceded the last, day.0I]
namely— c£anges
IV. Optical Changes induced by Magnetism.— induced by
In his 19th Series of i2esearc/ies, published in 1845, magnetism.
Dr Faraday announced “ The Magnetization of
Light and the Illumination of the Magnetic Lines of
Force,”—a title which, though intended to express
exactly the author’s idea of his discovery, perhaps
excited undue anticipations in the public mind. For
here we have no direct, or even apparently direct,
action of the magnetic force on a luminous ray, hut
only that a peculiar state is induced by magnetism
in some transparent bodies which produces an action
on light which they did not possess before, and which,
indeed, differed in some respects from any similar
action previously recognised.
Dr Faraday’s leading experiment is the following : (835.)
—A piece of “heavy glass,” or siliceous borate of of
lead, was placed lengthwise between the poles of ap0iariza.
powerful electro-magnet. A ray of plane-polarized of a ray of
light was transmitted through the glass parallel to Dght.
the line of the magnetic poles ; when the magnetic
energy was fully applied, the plane of polarization of
the light was found to have twisted round, similarly
982
MATHEMATICAL AND PHYSICAL SCIENCE.
FDiss. VI.
(836.)
Resembles
the action
of quartz,
but with a
difference.
(839.)
Vast detail
of the
science of
electricity.
Its nume¬
rous culti¬
vators.
(apparently) to what occurs when polarized light
passes through quartz or oil of turpentine. It is
found that a great number of solids and liquids are
subject to the magnetic influence in the same man¬
ner as in the case of “ heavy glass,” though to a
smaller amount.
Now, in reasoning on this experiment, it is to be
observed that no rotation of the ray takes place un¬
less there be a medium on which the magnetism im¬
presses its energy.1 Some molecular change, no
doubt, results, such as that which pressure gives to
glass, rendering it doubly refracting and depolariz¬
ing, or, to take a still closer analogy, when heat ap¬
plied to it conveys similar properties. Yet no one
imagines that these experiments show a direct reac¬
tion of heat, still less of mechanical compression, upon
light. Yet, with all abatements, Dr Faraday’s dis¬
covery is novel and singular; the more so, that this
constrained state differs from that naturally pos¬
sessed by quartz and certain liquids. The state mag¬
netically induced in a body causes the rotation of the
ray to be reversed when it moves in the contrary
direction ; that is, its rotation is right-handed when
the ray moves from the north to the south pole, but
left-handed when it moves from S. to N. But in
bodies in the natural state the rotation takes place
towards the same hand whatever be the path of the
body. Mr Airy has shown that this peculiarity ad¬
mits of being mathematically expressed in a manner
somewhat analogous to that imagined by Professor
MacCullagh in the case of quartz (512) ; but it is
not pretended that these formulae convey informa¬
tion as to the physical conditions on which these
singular phenomena depend.
Amongst Dr Faraday’s contributions to science (837.)
not connected with electricity, the most remarkable Dr Fara-
perhaps is the condensation of many gases into the ^ 1^“e’
liquid form by cold and pressure, of which he is the tain gases,
undoubted discoverer. This fact is highly interest¬
ing both in a scientific and practical point of view. In
the latter it was early applied by the late ingenious
Sir M. I. Brunei as a new moving power (375), and
it may not improbably yet be resorted to for that
purpose. The subsequent discovery of a mode of
solidifying carbonic acid by M. Thilorier is not only
interesting in itself, but affords a method of produc¬
ing more intense cold for experimental purposes
than any other previously known.
Dr Faraday still continues his laborious and fruit- (838.)
ful inquiries. Whilst he has attained almost every His wi(|e
titular honour which the world of science has to rePutatlon'
bestow (including that of associate of the French
Academy of Sciences), he has preserved a modesty
of character and a simplicity of life which enhance
the respect in which he is held by all who are ad¬
mitted to his nearer acquaintance. No one has more
successfully escaped the contentions which literary
rivalry so often produces ; and by his extraordinary
skill in expounding the most difficult researches,
whether made by himself or by others, he has main¬
tained (as I have already said) the early reputation
of the Itoyal Institution, and has immensely enlarged
the circle of those who are able to admire and appre¬
ciate his successes.
§ 6. Ohm—Daniell—Mr Wheatstone—M. Jacobi.—Laws of Electrical Conduction;—Constant
Battery;—Applications of Electricity to Telegraphs—Clocks—Motive Engines—the Electrotype.
We have traced in the last section the progress of
electrical and of electro-magnetic discovery since the
days of Davy and Oersted, as well exemplified in
the pre-eminent researches of Dr Faraday. In con¬
formity with the plan of this Dissertation (13),
(14), I have, on account of their immense interest
and importance, analyzed them more fully than
could possibly have been done were I to render
similar justice to all who have distinguished them¬
selves in the same career. Thus, France has pro¬
duced in M. Becquerel one of her most inge¬
nious and indefatigable experimentalists, full of de¬
votion to science, and giving up conscientiously the
whole of a long life to the cultivation of this parti¬
cular department. His discovery of the efficacy
of long-continued and very feeble voltaic actions
to produce crystallized earthy and metallic com¬
pounds not obtainable by chemical means is highly
important. Switzerland is proud of her two De la
Rives,2 and Italy of not a few disciples of Volta. In
Germany the number of electricians is greater than
in any other country; and as they have taken the lead
in obtaining correct measures of the electric forces,
and in determining (in many cases) the numerical laws
which regulate the efficiency of batteries and conduc¬
tors, and have applied these to many important
practical purposes, I shall devote a section to some
account of these, as Avell as to the beautiful experi¬
ments of our countryman Mr Wheatstone.
Ohm’s Law of Electrical Conduction. — Georg
Simon Ohm was born in Bavaria in 1787, and was
successively professor at Cologne, Niirnberg, and
(840.)
Ohm’s
theory of
electrical
conduction
1 I may here record that before the year 1835, I suspected that there might he some immediate action between circularly polar¬
ized light and a magnetized body, and made experiments in consequence in May 1836, which, however, led to no result. I
rather think, however, that these experiments deserve careful repetition under more varied circumstances.
2 MM. Becquerel and A. De la Rive have both published elaborate works on Electricity, to which the reader is referred for
details on this inexhaustible subject.
Chap. VII., § 6.]
ELECTRICITY.—OHM—DANIELL.
983
(841.)
Its merits
and de¬
fects.
(842.)
The prin¬
cipal laws
of conduc¬
tion.
Munich. He died on the 7th July 1854. His
theory of electrical conduction was not highly appre¬
ciated in Germany until it had received, in 1841, an
eminent mark of approval from the Royal Society of
London, by the award of their Copley medal. His
principal work on the Galvanic Circuit [Die galvan-
ische Kette mathematisch bearbeitet; Berlin, 1827)
has had a somewhat peculiar fate. Accepted by only
a few persons as a great discovery, it met with com¬
paratively little attention, at least until recently; yet
notwithstanding the long anticipation by Ohm of his
results, it has been his misfortune to have their ori¬
ginality contested.
It seems not difficult to account for the diversity
of estimation in which this work has been held. The
primary fault is the author’s own. He deduces the
strength of a voltaic current in any given circuit, and
the electroscopic excitement of each part of the cir¬
cuit, by means of reasoning seemingly a priori, from
certain assumed axioms submitted to mathematical
reasoning. The axioms are very simple ; the theory
founded on them is intended to correspond to Fourier’s
theory of heat, of which, indeed, in point of form, it is
a mere and literal copy ; but as every circumstance
which introduces real complication is soon left on
one side, the leading propositions are almost self-
evident results of the axioms. In short, the pa¬
rade of mathematics is uncalled for, and the whole
structure of the theory seems so slight and ques¬
tionable that one is surprised that it should ever
have been regarded as more than a clever expres¬
sion of some approximately true experimental laws.
It appears, indeed, that this is the simple fact;—
that the axioms were obtained from the results
which they seem to predict, and that Ohm was an
experimentalist before he became an author. In
this guise we understand how to treat the so-called
“ Laws of Ohm.” They are truly important empi¬
rical laws, calculated to guide the practical man in
applying and measuring galvanic forces, to enable
the theorist to form clearer notions of the different
(often confusing) effects of these forces, and to reduce
their varying energy to calculation ; but we must be
allowed to doubt whether Ohm has thrown any new
light on the real first axioms of electrical excitement
or transmission.
The most important of these laws refer to the
numerical measure of the voltaic stream circulating
in the conductor of a closed circuit. Such a closed
circuit may be imagined to consist of—(1.) an excitor
or battery; (2.) a conductor homogeneous or other¬
wise, but necessarily continuous, uniting the ends of
the battery. The exciting force is derived (we will
assume) from the chemical or thermo-electric action
present in the battery. The electric equilibrium
being disturbed, is restored more or less speedily
through the medium of the conductor which connects
the poles. If the conductor be good, the electricity
passes rapidly through it, and does not accumulate in
the battery; if the reverse, it accumulates until it ac¬
quires power to overcome the resistance, and then it
passes through in a stream less abundant, but of a
higher intensity. If the construction of the battery
does not permit that degree of intensity to be reach¬
ed, the electricity stagnates in the battery, the con¬
ductor cannot perform its office, no effect results. The Illustra-
whole maybe compared to a spout of water discharged tion‘
into a trough, from the bottom of which extends a
long narrow horizontal pipe. The water is the elec¬
tricity, the trough is the battery, the pipe is the con¬
ductor. If the pipe be very long and narrow, no
water at all will pass through it until the water in
the trough has attained a certain height, or has a
head of pressure sufficient to overcome the resistance
in the pipe. If the trough be filled to the brim
without the resistance being overcome, the trough is
as good as plugged, no motion takes place, the stream
regurgitates. The longer the pipe the feebler the
stream that passes; shorten the pipe indefinitely,
and the efflux depends only on the construction of
the trough. Indeed, the illustration might be pushed
considerably farther. The depth of the cistern re¬
presents the electro-motive force of the voltaic com¬
bination ; its area the size of the plates. By in¬
creasing the latter, we do not give the means of
overcoming more resistance; but when the resist¬
ance is small, we afford a larger supply without
lowering the level—i. e., the intensity.
Ohm regards the current as proportional to the elec- (843.)
tro-motive force directly, and to the resistances in- ^es'st"
versely ; and the latter are divided into (a) the re- ^Umated
sistance of the battery itself to the passage of the cur¬
rent ; (6) the resistance of the conductor. Now the
latter varies as the length of the wire completing the
circuit. We may therefore double its amount by
doubling the length of wire joining the poles ; and
if we observe the strength of the current passing
before and after this has been done, we have a mea¬
sure of a + 6 in the first experiment, and of a + 2 6
in the second ; and b being assumed to be known, a,
or the comparative resistance within the battery,
becomes known also.
The resistance of a standard copper wire a foot (844.)
long may be taken as the unit of resistance. Mr Standard
Wheatstone finds it convenient to assume a copperof resist'
wire a foot of which weighs 100 grains. M. JacobianCe'
prefers a metre of copper wire one millimetre in dia¬
meter. The resistance is as the length, and inversely
as the sectional area.
To measure the current two methods have chiefly (845.)
been used, and the results agree closely. One is Force of
the tangent compass. A voltaic current is allowed the current
to pass through a thick wire arranged in a vertical ~^an^®nt
circle. At the centre of the circle is placed a very ^
short magnetic needle. When a current passes the
needle is deflected ; and it is easy to show that the
deflecting forces are as the tangent of the angle of
deflection. A double or treble force in the circuit
984
MATHEMATICAL AND PHYSICAL SCIENCE.
[Drss. VI.
(846.)
Voltame¬
ter.
(847.)
(848.)
Rheostat
of MM.
Wheat¬
stone and
Jacobi.
(849.)
Farther
deductions
from Ohm's
theory.
(850.)
(851.)
Fechner’s
experi¬
ments.
produces a deflection of the needle whose tangent is
double or treble the first.
The other method is by Dr Faraday’s Voltameter.
The amount of water decomposed is directly as the
quantity of the current. The unit in this case is
one cubic centimetre of gas produced from water in a
minute.
These two measures agree. After being once com¬
pared, we may in all cases deduce the decomposing
force of a current from its effect upon a tangent com¬
pass.
Mr Wheatstone has facilitated the measurement
of voltaic effects by the invention of the rheostat, a
simple contrivance for introducing any desired length
of wire into a circuit, and thus estimating resistances
both of conductors and of batteries, and also the
electro-motive forces of different batteries. The re¬
sults appear to be extremely satisfactory. (Phil.
Trans., 1843.) The conducting power of different
metals drawn into wire will he inversely as the
lengths required to he introduced into the circuit to
reduce the strength of the current in a given pro¬
portion. The principle of the rheostat was inde¬
pendently applied to similar inquiries by M. Jacobi
of St Petersburg, in 1840.
The laws of Ohm farther proceed to expound the
effect of the size and number of the elementary cells
combined in a voltaic battery. The size of the plates
increases the quantity of electricity which escapes
through a short conductor, but has little effect upon
a long current. On the other hand, the multiplica¬
tion of elements produces no increase in the voltaic
stream when the connecting wire is short and when
it is also a good conductor, for the chief resistance
in the circuit is in that case the battery itself, which
resistance increases with the number of elements, just
as the force which overcomes it increases. If, on
the other hand, the chief resistance be extraneous to
the battery, the addition of more elements increases
the power without much increasing the resistance.
All this scarcely requires mathematical proof. It is
very evident, and very just, and it is borne out by
experiment.
Ohm’s theory farther gives the partial effects of a
current branching into various unequally good con¬
ductors, and into other details, particularly as to the
electric tension in different parts of a circuit. It is,
however, to he observed, that the whole is based on
the assumption that the dissipation of electricity from
the surface of the conductor is insensible.
It is only justice here to add, that the theory of
Ohm owes much, if not most, of its value to the ex¬
periments of Fechner in Germany; and that its re¬
ception in France and England is mainly due to the
ingenious and (in many cases) independent experi¬
ments of M. Pouillet and Mr Wheatstone.
Daniell’s Constant Battery.—This seems the pro- (852.)
per place to mention an invention which has exer-
cised a remarkable influence on the progress of prac- nieii—the
tical electricity—I mean the Constant Battery. I constant
believe that the merit of this application is entirely battery-
due to the late Professor Daniell,1 although the Ger¬
man writers (who manifest throughout a singular
sensibility with regard to their national claims to
electrical improvements) seem to claim it for their
countrymen. Every battery previously constructed
diminished rapidly in energy from the instant of being
charged. This was chiefly due to two causes ; first, to
the acid becoming gradually charged with oxide of
zinc; and, secondly, to the appearance of “ nascent”
hydrogen arising from the decomposition of water at
the copper surface where it prevented effectual con¬
duction of the electricity. These sources of di¬
minished effect were prevented in the following
way:—Instead of a single cell containing one fluid
moistening both the copper and the zinc, a double
cell was formed by means of a partition of bladder
or porous earthenware. The partition next the zinc
was filled with dilute sulphuric acid; the partition
next the copper with a solution of sulphate of cop¬
per, also acidulated. When galvanic action proceeds,
both fluids are decomposed ; but whilst that in the
zinc cell becomes charged with oxide of zinc, it is
at the same time continually acidulated by the
electro-chemical transfer of acid from the decom¬
position of sulphate of copper in the copper cell;
and the copper set free from the same combination
in the form of oxide is metallically reduced by com¬
bining with the “ nascent” hydrogen (the oxygen
derived from the water decomposed having combined
with the zinc), and the metallic copper is deposited in
an ever fresh film on the surface of the copper plate.
This beautiful invention was described in 1836.
Many other batteries on the same principle have
been since contrived and described; several are more
powerful, but none perhaps are so constant in their
action.
Application of Electricity to the Arts—MM. (853.)
Wheatstone and Jacobi.—I have selected Messrs Appiica-
Charles Wheatstone and M. H. Jacobi as the repre- ^"tHdty
sentatives of a numerous class of ingenious men who t0 the arts.
have shown great felicity of invention in applying in¬
genious mechanism to render electric agency available
in the arts. We here again find the reciprocal influ¬
ence of art upon science, to which I have elsewhere
1 John Frederic Daniell, Professor of Chemistry in King’s College, London, was born in 1790. He was the author of a work
on Chemical Philosophy, of Meteorological Essays, and of numerous papers in the Philosophical Transactions, many of which were
connected with Voltaic Action. His work on Meteorology contributed materially to the progress of that science, as did the in¬
vention of his Hygrometer (notwithstanding certain defects in that instrument) to the theory and practice of Hygrometry. For
his Constant Battery Mr Daniell received the Copley medal of the Royal Society. His death took place from apoplexy while
attending a council meeting of the Royal Society on the 13th March 1845.
Chap. VII., § 6.] ELECTRICITY.—MM. WHEATSTONE AND JACOBI.
985
(854.)
(855.)
Mr Wheat¬
stone on
the velo¬
city of elec¬
tric con¬
duction.
adverted (32, &c.) The requirements of practice
are magnificent experiments, such as no indivi¬
dual and no scientific Society would think of exe¬
cuting for the illustration of theory. It is not in
the least my purpose to transfer to these two gentle¬
men an exclusive merit which they need not be un¬
willing to share with other energetic and able com¬
petitors in the hard-run race of scientific applications.
They occupy, however, perhaps the most marked and
distinguished place, and the field is so wide and in¬
cludes so many minute details, that it requires all
our resolution to fix our eyes steadily on the most
considerable acquisitions—the nobler sheaves of so
prolific a harvest.
I shall connect, then, with the name of Mr
Wheatstone, (1), the apparatus for determining the
velocity of electrical conduction, (2), the electric tele¬
graph and clock,—with that of M. Jacobi, (3), elec¬
trodynamic machines, and (4), the electrotype.
I. The apparatus used by Mr Wheatstone in 1834
for measuring the velocity of the passage of the elec¬
trical impulse through a good insulated conductor
, such as a copper wire, deserves particular notice
from its great ingenuity, and from its general appli¬
cation to the measurement of short intervals of time.
Let a copper conducting wire of half a mile long be
so convoluted that the middle and the two ends of
the wire may be brought near together, the whole
being perfectly insulated. Let the wire be slightly in¬
terrupted at these three places, and the whole put
into connection at pleasure with an electric machine
or battery. When contact is made, three sparks will
take place. Let the two end sparks be called A and C
and the middle one B. As the three sparks take place
close to each other, they can easily be seen at once
reflected in a small plane mirror. Let now this small
mirror be put in very rapid rotation round a hori¬
zontal axis so placed that the sparks (if they occur in
the suitable part of the revolution) may be reflected
together to the eye. Imagine the rotation to become
immensely rapid:—in Mr Wheatstone’s apparatus
the velocity reached 800 times in a second; conse¬
quently the mirror described 1° in mo x awth part of a
second; i. e., in °f a second. But for 1° of
rotation of a mirror the reflected image will describe
an arc of 2°. Supposing then that all the sparks occur
at the same absolute instant of time, they will be
seen in one line (supposing the points of the inter¬
rupted circuit in a line), but if either spark occur
later than the others by only of a second,
the mirror will have revolved so much in the interval
as to displace the image of that spark relatively to
the others by the very palpable angular amount of
2°. In the copper wire half a mile long, the end
sparks occurred simultaneously, whilst the middle
spark occurred later by about one millionth of a
second ; giving a velocity of transmission (according
to Mr W.) of 288,000 miles a second, or somewhat
greater than that of light.1 * The velocity in an iron
telegraph-wire, ascertained lately in America with
much greater accuracy, and by a different method, is
only 16,000 English miles a second; but doubts have
been thrown upon the correct interpretation of these
experiments. Those of M. Fizeau on the telegraphic
lines of France give results more conformable to
Mr W'heatstone’s, namely, about 70,000 English
miles per second for iron, and 120,000 for copper
wire. The duration of a spark drawn immediately
from the battery is insensible, but in Mr Wheatstone’s
experiment it lasted of a second when trans¬
mitted by a copper wire half a mile long.
II. Electric Telegraph and Clocks.—The idea of (856.)
using the transmission of electricity to communicate Electric
signals is so obvious as hardly to deserve the name e^-i'y
of an invention, the prodigious velocity of common history,
electricity in wires having been established by Watson
before the middle of the last century. The earliest
proposal of the kind appears in the Scots Magazine
for February 1753, where a correspondent from Ren¬
frew, who signs himself C. M., proposes several kinds
of telegraphs acting by the attractive power of electri¬
city, conveyed by a series of parallel wires correspond¬
ing in number to the letters of the alphabet, and in¬
sulated by supports of glass or jeweller’s cement at
every twenty yards. Words are to be spelt by the
electricity attracting letters, or by striking bells cor¬
responding to letters. One Lesage, in 1782, and even
long before, proposed to convey twenty-four insulated
wires in a subterranean tube, and to indicate the letters
of the alphabet by means of the attraction of light
bodies. In 1811 Sommering suggested a similar ap¬
plication of voltaic electricity, chemical decomposition
being the effect observed. Oersted first, and then Am¬
pere (1820) suggested the use of magnetic deflections
for the same purpose, which is nothing else than the
needle telegraph in general use in England ; but they
contented themselves with the suggestion merely.
MM. Gauss and Weber communicated signals at
Gottingen in 1833 or 1834 to a considerable dis¬
tance, and gave them the signification of letters.
This was the first accomplishment of telegraphic com¬
munication by means of electricity, and it realized
the fancy of Strada, quoted by Addison, of sym¬
pathetic magnets. It was, however, a mere appen¬
dage to a magnetic observatory, and its application
and diffusion on a great scale seems to have required
a distinct effort; for several years elapsed before we
hear more of the telegraph.
The year 1837 is the date of the realized electric (857.)
telegraph. We find three distinct claimants, of whose Telegraphs
ox 7 o f* AIAJ
independent merits there is no reason whatever to jIorse'
doubt, though how much of the merit of all must be steinheil,
considered due to MM. Gauss and Weber, who firstand Wheat-
made the experiment, though they did not offer itstone-
VOL. i.
1 The numerical value is of course only a very rude estimation.
6 i
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. YI.
i
I
986
for general adoption in a convenient form, is a matter
which we need not here decide. The three indepen¬
dent inventors (I name them alphabetically) are Mr
Morse of the United States, M. Steinheil of Munich,
and Mr Wheatstone of London. The telegraph of
the two last resembles in principle Oersted’s and
Gauss’s ; that of the first is entirely original, and con¬
sists in making a ribbon of paper move by clockwork,
whilst interrupted marks are impressed upon it by
a pen or stamp of some kind brought in contact with
the ribbon by the attraction of a temporary magnet,
which is excited by the circulation of the telegraphic
current of electricity. In the telegraphs of MM.
Wheatstone and Steinheil the needle moves only to
the right or left; and by the combination of a certain
number of right and left motions, either with one or
with two independent needles acted on at once by
distinct currents, the alphabet is easily, though some¬
what tediously constructed. Such, however, is the
dexterity which practice gives, that forty or even
more of such complex signals are transmitted and
registered per minute.1
(858.) It has already been said that we claim the exclu¬
sive invention of the electric telegraph for no one in¬
dividual. But of the several inventors none pro¬
bably has shown such perseverance and skill in over¬
coming difficulties as Mr Wheatstone.2 His telegraph
accordingly was in general use in England before M.
Steinheil was able to obtain a similar success in
Germany. The telegraphs of Mr Morse are naturally
preferred in America, and they have this inestimable
advantage, that they preserve a permanent record of
the despatches which they convey.
(859.) There is one circumstance connected with the elec-
The earth- |rjc telegraph deserving of particular notice—I mean
circuit. apparently infinite conducting power of the earth
when made to act as the vehicle of the return current.
Setting all theory aside, it is an unquestionable fact,
that if a telegraphic communication be made, sup¬
pose from London to Brighton, by means of a wire
going thither, passing through a galvanometer, and
then returning, the force of the current shown by
the galvanometer at Brighton will be almost ex¬
actly doubled, if, instead of the return wire, we
establish a good communication between the end of
the conducting wire and the mass of the earth at
Brighton. The whole resistance of the return wire
is at once dispensed with ! This fact was more than
suspected by the ingenious M. Steinheil in 1838;
but, from some cause or other, it obtained little
publicity; nor does the author appear to have ex¬
erted himself to remove the reasonable prejudices
with which so singular a paradox was naturally re¬
ceived. A most ingenious artist, Mr Bain, estab¬
lished for himself the principle, and proclaimed its
application somewhat later; and in 1843, perhaps
the first entirely convincing experiments were made
by M. Matteucci at Pisa. From this time the double
wire required to move the needle telegraph was
reduced to a single one. The explanation of this
curious fact appears to be,—not that the electricity
is conducted back by the earth to its origin at the
battery,—but that the molecular disturbance po-
larly communicated along the conducting wire to its
farther end being effectually relieved by perfect com¬
munication with a vast reservoir of neutral electri¬
city like the earth, conduction proceeds in an unin¬
terrupted manner, and to an unlimited extent.
Of submarine telegraphs, it is sufficient to state (860.)
that the isolation is obtained by inserting the con- Submarine
ducting wires in a mass of gutta percha, and that
the first on a considerable scale was sunk between
Dover and Cape Gris Nez, on the French coast, in
August 1851.
The applications of electricity to the measurement (861.)
of time are so numerous, that I can only refer ge¬
nerally to the principal contrivances.
1. The simple electric clock of Mr Bain derives its (862.)
maintaining power from two large plates of copper ^1(Jc^ric
and zinc (or more simply zinc and charcoal) sunk in
the earth, which affords for a very long time a con¬
tinuous supply of voltaic electricity. The current is
conveyed into the bob of the pendulum, where it
traverses a long coil of wire ; and as the pendulum
oscillates, the current (by a simple shifting contriv¬
ance) is reversed at each vibration. A stationary
bar-magnet is placed so that when the pendulum
moves, the voltaic coil of the bob embraces the mag¬
net, and the direction of the current is such as by
the electro-magnetic reaction to strengthen and main¬
tain the vibratory movement, which is by this means
perpetuated.
2. Sympathetic clocks.—By means similar to those (863.)
just explained, one standard clock anyhow regulated Sympathe-
may, by means of magneto-electric currents, conveytic clocks-
absolutely isochronous movements to any number of
affiliated clocks at any distance. Probably the first
application of the kind was made by M. Steinheil.
3. American electric-registration clocks.—Mr (864.)
Locke proposed to register the instant of an event American
occurring in the following way: A ribbon of®^™"
paper being put in uniform motion, as in Morse’s tion clocks,
telegraph, a dot is imprinted on it every second by
1 Occasionally 18 or 20 words per minute have been telegraphed.
2 I ought to mention that the practical introduction of the electric telegraph in England is in no small degree due to the
energy of Mr Fothergill Cooke, joint patentee with Mr Wheatstone for the invention. The question of the respective shares of
these gentlemen in the merit of telegraphic communication was submitted, in 1841, to the arbitration of Sir Marc Brunei and
the late Mr Daniell, the result of which appears to leave the preponderance of merit in some respects ambiguous ; neverthe¬
less, in a history of Science, Mr Wheatstone is clearly entitled to the pre-eminent place. Several pamphlets have also been sub¬
sequently published by the parties. It is significant that Mr Cooke admits having borrowed his idea from becoming acquainted,
at Heidelberg, in March 1836, with Gauss’s experiments.
Chap. VII., § 7.]
ELECTRICITY.—M. JACOBI—CAVENDISH.
987
(865.)
Chrono-
scopes.
(866.)
Electro¬
magnetism
as a prime
mover.
(867.)
means of a simple connection with, an astronomical
clock. A separate marking apparatus under the con¬
trol of the experimenter enables him to interpolate a
dot or mark corresponding to the instant of any
event happening—such, for instance, as the transit of
a star. This method has the great advantage of
leaving the observer at entire liberty to watch the
object without having to attend to the beats of the
clock, whilst it renders mistakes next to impossible.
It has been successfully applied to the determination
of longitudes, and more recently to all kinds of astro¬
nomical observations, by Mr Bond in America, and
by Mr Airy at Gi’eenwich (231).
4. Chronoscopes, or instruments for the measure¬
ment of excessively short intervals of time, such as
the flight of military projectiles, and even the trans¬
mission of sensation and motion along nervous
fibres.—Such instruments have been constructed on
a great variety of principles. Those of M. Pouillet,
Mr Wheatstone, and Mr Siemens, deserve especial
mention.
III. Of electro-magnetism used as a moving
power, we need say little. No one can witness the
astonishing experiment of the sudden creation of
magnetic power sufficient to sustain one or two tons
by the voltaic dissolution of a few grains of zinc,
without having the idea suggested of a continuous
moving force. This enormous power is, however,
exerted through a space so excessively minute, that
its dynamical effect is always small; and, though it
is, of course, possible to produce an engine by a
sufficiently gigantic arrangement, the success has
hitherto not been encouraging.
The rotations of Mr Faraday and Dr Ritchie were
electro-dynamic machines on a small scale. They M. Jacobi's
were (probably) first mechanically applied by M. dal machiTie9.
Negro in 1833, but more systematically by Mr. M. H.
Jacobi, of St Petersburg, the following year. It is
stated that the latter gentleman moved a boat on the
Neva with an electro-dynamic motor equivalent to
three-fourths of a horse power. He has also inves¬
tigated the theory of these machines, and the most
advantageous circumstances of their employment.
The principle is the alternate attraction and repul¬
sion of two temporary magnets (one of which re¬
volves), the current of electricity being suddenly
changed at the critical part of the revolution.
IV. To M. J acobi—almost simultaneously with Mr (868.)
Spencer of Liverpool—we are also indebted for one Electr°-
of the simplest and most elegant applications of elec- voUatype •
tricity, the Galvano-plastic art, or Voltatype. In —MAE Ja-’
this, advantage is taken of the perfectly metallic state col,i and
in which the base of a metallic salt is deposited at sPencer-
the negative pole of a voltaic combination. In the
case, for example, of the decomposition of sulphate
of copper, the sulphuric acid unites with the positive
wire, or remains suspended, while the metallic cop¬
per is slowly and homogeneously deposited on the
surface of any object (rendered conducting by the
application of black lead or otherwise), of which it
forms a perfect mould, from which a fresh cast or
facsimile in metal of the original object may be ob¬
tained by a repetition of the process. To see the
veins of a leaf, or the delicate wing of an insect, thus
metallized, is certainly an astonishing thing; and
the applications to the useful arts are far too nume¬
rous to be noticed here. Daniell’s invention of the
Constant Battery evidently suggested the Voltatype.
7. Cavendish—Coulomb—Experimental Laws of the Distribution of Statical Electricity;—
Mathematical Theory of the same.—Poisson—Mathematical Theory of Statical Electricity
and of Magnetism generalized. Green ; Professor William Thomson.
(869.) Having thus brought down the history of galvanic
Statical^ 01. voltaic electricity, and that of the wonderful dis-
Klectricity. coveries connected with it, to our own time, I shall
in this section briefly notice the more intermitting
progress during the same period of our knowledge
of the quantitative laws which regulate the distribu¬
tion of statical electricity on bodies charged with it.
(-§70 ) “ iEpinus and Coulomb,” says Dr Whewell,1 “ were
iEpinus, two of the most eminent physical philosophers of
Cavendish, the last century.” They laid the foundations of an
lomb U" exact science of statical electricity; and a third, and
still more eminent name, deserves to be connected
with theirs,—that of Cavendish, of whose general
labours I have already given some account in the
Second section of the chapter on Heat. The labours
of iEpinus belong rather to the period embraced in
the previous Dissertation, where they have been re¬
ferred to by Sir John Leslie.
Perhaps the most elaborate of the memoirs not ^
strictly chemical which Cavendish published were Caven-
those on electricity. The Franklinian hypothesis of dish’s
a single fluid in excess or in defect of its average theor7 aild
state producing the phenomena then known as elec- ^ents!
trical, offered a tempting field to an experimental
philosopher well trained in the mathematical know¬
ledge of the day ; and his paper on this subject shows
extreme care in its conception and execution. He
assumes, as a matter of necessity, the repulsion of
matter for matter at sensible distances, considered
apart from the electricity always combined with it in
greater or less quantity. The indifterence of matter
under ordinary circumstances is held to arise from
the union with it of a sufficient amount of electricity
to neutralize the repulsion of the matter. In short,
the electric fluid is considered as a second kind of
matter repelling its own particles, and attracting those
1 History of the Inductive Sciences, vol. Hi., p. 34, 2d edition.
988
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
faven- 0f other matter with a force varying inversely as some
electrical ^ess Power the distance than the cube. Common
theory and matter repels its own particles and attracts electric
experi- particles according to the same law. The limitation
ments. ag a p0wer below the inverse cube of the distance
is necessary, since were the decrease of force more
rapid, a particle would not be sensibly affected by the
repulsion of any portion of the fluid except what was
placed close to it. The hypothesis of Cavendish and
his mode of reasoning from it wrere in general the
same as those of iEpinus; hut Cavendish was not
aware of the researches of the Swedish philosopher
until his own memoir was completed. The number
of facts accurately ascertained concerning electricity
was at that time too small to admit of very precise
numerical comparisons, but the ordinary cases of at¬
traction, repulsion, and induction, were perspicuously
explained by the theory ; and had the inverse square
of the distance been assumed (as it very safely might
have been) to represent the law of diminishing re¬
pulsion, several of the theorems would have as¬
sumed a much more definite character, as was
shown by Robison. Cavendish first demonstrated
in his paper of 1771 that electricity must be
confined close to the surface of a spherical body.
This memoir also includes a correct theory of
the Leyden phial, a just approximation to the law
of attraction as the inverse square of the distance,
a theory of conduction, and of the distribution of
electricity on insulated conductors placed at a dis¬
tance but connected by a fine wire or electric canal;
and it was only the prelude to other researches never
published, but of which some remarkable fragments
exist amongst his manuscripts. Professor William
Thomson, who has partly examined these, informs
me that they contain the experimental solution of
problems such as the following: “ To compare the
quantities of electricity on a spherical conductor,
and a plane disk of equal diameter connected by a
long conducting wire.” Cavendish found that the
sphere holds 1-57 times the electricity of the plate,
a result exactly coincident with the deductions of
theory.
(872.) I may here (for the sake of biographical connection)
arfarti^05 men^on Cavendish’s paper on the Torpedo, as a re-
ficial markable instance of the explanation of an obscure
torpedo, natural phenomenon, by the analogous effects of an
artificial imitation. The experiments of Walsh on the
Electrical Fishes have been cited in the preceding Dis¬
sertation. Cavendish undertook the bold task of prov¬
ing, that all the external effects of the shock under
varied circumstances, might be reproduced by a com¬
bination of Leyden jars duly protected. He made an
artificial torpedo, consisting of 49 jars in a frame
covered with leather, and he succeeded in obtaining
shocks in air as in water, exactly comparable to those
obtained from the live fish by Walsh. But perhaps the
most striking part of the paper is the incidental men¬
tion of several laws of electricity then certainly new, and
which he had deduced from experiment. Thus,he af¬
firms the conducting power of iron for electricity to
exceed 400,000 times that of distilled water, which he
states to be equivalent to the fact, that a conductor of
equal diameter will transmit as much electricity if the
iron be 400,000 times longer than the water—a law
conformable to that of Ohm. He farther estimates
the conducting power of sea-water at 100 times, but
of saturated brine at 720 times that of pure water.
Again, the quantity of electricity required to raise the
charge on different jars or plates to the same inten¬
sity he finds to be directly as the area of the coating,
and inversely as the thickness of the plate, and he
applies this just conclusion with great ingenuity to
explain the surprising power of the torpedo’s shock
by the extreme fineness of the membranes separating
the columns of the electrical organs.
Coulomb (born 1736, died 18061 2) was a person of (873.)
less genius and less mathematical attainment than Coulonibjs
Cavendish, yet he had very considerable geometrical eXperi_
ability and much facility in applying it to the results meats,
of experiments, which he conducted with the greatest
ingenuity and accuracy. In the latter respect he has
seldom been surpassed. His methods, and even his
numbers, are still, after a lapse of more than half a
century, in many cases the best Ave can quote.
Like Ca\rendish, he was de\Toted to quantitative esti¬
mations of phenomena.
His two greatest inventions were the balance of C8?4-)
torsion and the proof plane. In the course of hisjanceof
strictly mechanical researches (which, as we have torsion
seen in the chapter on Mechanics, Art. 339, &c., were and the
numerous and important) he ascertained the laws of Proof
a / Diane
torsion. Within the limits of perfect elasticity, he
found that the force is as the angle of torsion of the
wire or fibre, and inversely as its length. An almost
indefinite minuteness may thus be attained in the mea¬
sure of forces which may be balanced by the elastic tor¬
sion of a wire. We have seen (Astronomy, § 1, Art.
156) Iioav it was applied by Michell and Ca\mndish to
measure the gravitation of bodies. Coulomb’s inven¬
tion dates at least from 1784. By means of it he
established (in a different and perhaps more satisfac¬
tory way than had been done by Robison in 1769) that
the electric and magnetic forces vary according to the
Newtonian law;3 and with the aid of the “proof
plane” he obtained exact measures of the electric
tension on any part of an excited body. The “ proof
plane” consists of a small gilt disk with an insulat-
1 For a farther account of Coulomb, see the chapter on Mechanics, § 2.
2 Besides this law, Coulomb experimentally proved two others of great importance:—1. That the electricity of an elec¬
trified conductor resides wholly on its surface. 2. That the interior of such a conductor is in a condition absolutely undisturbed
by the presence of other external excited bodies.
Chap. VII., § 7.]
ELECTRICITY.—COULOMB—POISSON—GREEN.
989
ing handle, which being applied flat-wise to the sur¬
face of an excited body takes off a portion of electri¬
city, which is found in all cases to be proportioned
to the electric excitement of the part which it had
touched; being then presented to the torsion balance
properly electrified, it shows by the repulsive effect
produced, the relative tension of the part of the
body whence the sample was obtained.
^ (875.) jn manner Coulomb determined the distribu¬
tion of electricity upon electrified spheres at and after
contact with one another;—on spheres inductively
electrified,—on rods and plates and other figures; and
his results, so far as they have been compared with
theory, give evidence of the care and skill with which
they were obtained, allowance being in all cases made
for the loss of electricity by imperfect insulation. He
also laboured with praiseworthy diligence to compare
his results with the theory which he adopted of two
fluids, each attracting the particles of the other and
repelling their own according to the Newtonian law.
The iEpinian theory admits of only one fluid, but as it
assumes a repulsion between the elementary particles
matter it cannot be said to gain much in simplicity,
whilst the mathematical results of either hypothesis
are in general the same. M. Mosotti has endea¬
voured recently to revive the view of Franklin and
of iEpinus, so as to include, after the manner of
Boscovich, the entire mechanical properties of
matter.
(876.) The doctrine of attractions is a complex and diffi-
electrfcaf cu^ one even when the distribution of the attracting
attractions matter, as well as the fundamental law of attraction,
and repul- is known. But it becomes much more so when the
*ions. distribution of the attracting matter is itself the
result of the very effect which it is the object
of the problem to discover. If two homogeneous
spheres attract one another, molecule to molecule, by
the law of gravity, the problem is easy, provided the
matter be rigid, and the distribution of it therefore
unchanged ; but if two such spheres be charged with
the mobile electric fluid (using tbe term as a mere
abbreviation), the case is very different, for now the
electricity tends to shun the nearest points of each
sphere, and to accumulate itself towards the remoter
parts of their surfaces. The distribution of the
electricity, and also the repulsive effect at any point,
are both to be found simultaneously. The calcula¬
tions of Coulomb were inadequate (as has been said)
to such a solution ; he contented himself with comput¬
ing the effect of certain simple distributions which evi¬
dently lay on opposite sides of the truth, and com¬
paring them with the result of experiment. Though
any one such comparison might avail little, the
cumulative evidence of many imperfect comparisons
argued favourably for the truth of the hypothesis.
(877.) At the very time that Coulomb was pursuing this
Its prin- inquiry, Legendre first, and then Laplace, were in-
ciples de- venting and improving those subtle and powerful
Coulomb, mathematical methods at which we have glanced in
the chapter on Physical Astronomy, Art. 99, &c., Laplace,
for estimating attractions by a general method. Le- and Po.is*
gendre’s principles of calculation applied to cases ofson*
the symmetrical distribution of the attractive sub¬
stances, but Laplace escaped this restriction. The
problem is reduced to finding a quantity usually de¬
noted by the letter Y, called by some writers the
potential, for the given body or surface, the expression Potential.
for which may in each case be expanded into a series,
the co-efficients of the terms of which (known as
Laplace’s co-efficients) are connected by certain rela¬
tions which are evolved from the conditions of the
problem. It was M. Biot first of all, but principally
Poisson, who applied this method to electrical, and
subsequently to magnetical phenomena. Poisson,
with great labour, succeeded in representing correctly
by analysis the conditions of some of Coulomb’s ex¬
periments on spheres and ellipsoids. But it must
be owned that the complication of the analysis, the
difficulty of applying it to any but the very simplest
cases, and the considerable latitude of the errors of
experiment, rendered the results rather analytical
exercises than solid bases for physical induction ;
which may in some degree account for the manner
in which Sir John Leslie mentions them in his Dis¬
sertation. Poisson (as I have elsewhere remarked)
had not the talent of conducting his mathematics in
a fei'tile direction, and usually left the fields of ex¬
perimental physics on which he touched nearly as
barren as he found them. But this is no rea¬
son why other mathematical reasoners may not
obtain more pregnant results. We shall see in the
next section that Gauss, a distinguished contempo¬
rary of Poisson, by treating the great problem
of the distribution of the magnetism of the globe
(in many respects similar to those of the theory
of electricity) with the utmost mathematical gene¬
rality, has obtained results of great novelty and
importance ; that he has not only shown experi¬
menters how to proceed, but has invented instru¬
ments for them to use. A similar step has not yet
been taken in electricity. Notwithstanding the un¬
questionable beauty of Sir William Harris’s methods
of measuring electrical attractions (PAz7. Trans.
1834), they are little adapted for comparison with
theory, and Coulomb’s experiments still remain the
standard ones on the subject.
The theory of Coulomb has, however, been ably ge- (878.)
neralized by Green, a nearly self-taught mathemati- Writings
cian of great originality, who died at a premature age.
In a memoir on electricity privately printed about Professor
1830 he generalized Poisson’s methods and ap-W. Thom-
plied them to a number of new cases. His paper son‘
was reprinted a few years since in Crelle’s Journal.
To him I believe is due the term potential. Several
continental mathematicians of eminence have added
some steps to the theory of electricity, but probably
the most important from its fertility and simplicity
is a theorem discovered*by Professor William Thom-
990
MATHEMATICAL AND PHYSICAL SCIENCE.
Electrical
images.
(879.)
Applica¬
tion of the
theory of
magnet¬
ism to
correct
ships’
compasses.
MM. Bar-
low and
Airy.
(880.)
Recent
history of
terrestrial
magnet¬
ism.
(881.)
Professor
Hansteen
—Magne-
tismus der
Erde.
Variation
or decli¬
nation.
[Diss. VI.
son of Glasgow, for reducing the electrical effects of
electrified spheres upon points or other spheres with¬
out them to those of electrified points in certain po¬
sitions replacing the spheres, which points, from
certain analogies to well known optical formula},
Professor Thomson has designated electrical images.1
The mathematical theory of magnetism has re¬
ceived a highly practical application in the correction
of the deviation of compass due to the local attrac¬
tion of ships. Professor Barlow of Woolwich led the
way in attempting practically to correct the errors
thence arising. But when ships began to be con¬
structed almost entirely of iron, the use of his “ cor¬
recting plate” was found to be totally insufficient.
To the Rev. Dr Scoresby, practical navigation is
indebted for many ingenious observations on the
magnetism of ships, and suggestions as to the means
of allowing for it; while Mr Airy and Mr Archibald
Smith have the merit of applying the Theory of
Magnetism to the case in question. Mr Airy’s in¬
vestigations may be found in the Philosophical
Transactions for 1839 and 1855 ; from which it
appears that the effects of local magnetism in a ves¬
sel may be speedily and effectually corrected for a
given place by the use of two permanent magnets
placed in rectangular positions relatively to the com¬
pass ; and by the use of a mass of soft iron in a third
direction. But grave doubts still remain as to the
possibility of rendering such corrections permanent,
and applicable in all magnetic latitudes. A great
step has, however, been gained by putting the power
of readily verifying the compass corrections in any
part of the world in the hands of every intelligent
captain.
§ 8. Professor Hansteen—Baron A. von Humboldt—Gauss—Major-General Sabine Captain
sir J. C. Ross. Progress of our Knowledge of Terrestrial Magnetism in the present Century.
I could hardly have intentionally selected a more proposed the hypothesis of two pairs of magnetic
characteristic example of the scientific progress of poles interior to the globe, of which one pair re-
the nineteenth century than the recent history of volves slowly.
terrestrial magnetism, even had it not accidentally This hypothesis, little thought of at the time, (882.)
formed the closing section of this Dissertation. The and perhaps of little value except as a help towards
combination of extended methodical research in ob- the formal representation of the facts, appears to yai.iat;on
taining physical data, with mathematical skill in have been revived by Wilcke, a Swede, whose la- charts.
comparing them and in deducing from them the hours attracted the attention of Professor Hansteen
most important results, has been attended with first in 1807. M. Hansteen found the results of his
merited success. I regret that the unforeseen extent own collections to coincide well with Halley’s chart
of this historical sketch compels me to touch with for 1700, and also with the hypothesis ot four poles,
great brevity on the leading points of this research. two in each hemisphere, one stronger than the other.
Professor Christopher Hansteen, of Christiania, It results from these charts that the Line of No Va- Line of No
in Norway, is the person who has given pro- riation, which, in 1600, formed a remarkable arch- 'nation,
bably the greatest impulse in recent times to like curve, stretching from the Gulf of Mexico to
the efforts to methodize the facts and laws of near the North Cape of Norway, then descending
the earth’s magnetism. M. Hansteen was born through Central Europe to the Gulf of Guinea, had,
26th September 1783, and is Professor of Astro- during the seventeenth and eighteenth centuries, be-
nomy in the University of Christiania, and Direc- come gradually flattened (having passed through
tor of the Observatory. His dissertation, entitled Paris in 1669, and through London twelve years
Magnetismus der Erde, published in 1819, which earlier), and at present this part of the line of No
received a prize from the Royal Danish Academy, Variation is confined to the American continent and
recapitulated all the authentic facts obtained by neighbouring seas. Another and more complicated
voyagers and others from the earliest times. It branch of the same line traverses the Pacific Ocean,
will be recollected2 that Halley had represented making a complex serpentine track through East-
the magnetic variation at different parts of the ern Asia and Siberia. The line of No \ ariation
globe by lines traced on Mercator’s chart, and may be expected to pass through those points of the
passing through all places where the variation earth’s surface towards which the needle converges,
(or declination) of the needle from the true north which are sometimes called the magnetic poles (of
was equal; and being well aware of the progressive which more presently), and of which M. Hansteen
(or secular) changes in the course of these lines, he concludes the position to be as follows :3
1 Cambridge Mathematical Journal, 1850.
2 See Fifth Dissertation, p. 741. . ....
3 From M. Hansteen’s recent paper on the Secular Change of the Dip (Copenhagen, 1855). In this ingenious memoir it is in¬
ferred, with considerable plausibility, that the annual diminution of the dip is decreasing, and consequently that a minimum oi
dip will occur in Europe before the close of this century.
Chap. VII.,§ 8.] ELECTRICITY (.MAGNETISM).— M. HANSTEEN. 991
Position of
magnetic
centres or
poles.
Dist. from Long. E. from
Pole of Earth. Greenwich.
N, or strongest northern pole (N. America), for 1838   25° 22' 280° 197
«, or weakest northern pole (Siberia), for 1829    7 57 114 33
S, or strongest southern pole (S. from Australia), for 1845  21 9 131 28
s, or weakest southern pole (S. from Tierra del Fuego), for 1842. 13 53 216 26
Annual Variation
in E. Longitude.
+ 15''5
+ 43 -4 - O'-153 (t-1608)*
— 4-0
— 16 5
* t denotes the current year. This result appears very uncertain. It gives about + 6' -5 of annual change at the present time.
Ihe latitudes of these “points of convergence55 are also varying.
Variation maps of a different kind have been con¬
structed by the French Admiral Duperrey, in which
the actual direction of the needle is represented by
arrows. The above positions of the magnetic poles
were deduced by Mr Hansteen from the apparent
convergency of the magnetic needle towards those
four points. The earlier observations appear to be
more precise than might have been expected.
(883.) Professor Hansteen also constructed charts of the
Lines Ot lines 0f equal dip. In certain positions between the
tropics the dip is nothing, or the freely suspended
magnetic needle remains horizontal. The line con¬
necting these places is called the magnetic equator.
It is an undulating line inclined somewhere near 12°
or 13° to the terrestrial equator, and cutting it in
two points not exactly opposite, but in about 3° 20'
and 174° 30' of east longitude from Paris, according
to Admiral Duperrey’s observations in 1825. The
position of these nodes is, however, variable. The
north end of the needle (as is well known) dips
more and more in the northern hemisphere, until
in a certain place it becomes vertical, where there¬
fore the horizontal component of the magnetic
force is nothing, and the common compass loses
altogether its directive power. Similar phenomena
occur in the southern hemisphere. Lines of dip
of 10°, 20°, &c., may be drawn, and where the dip
is 90° there is a true magnetic pole. The best obser¬
vations seem to show that there is but one such true
pole in each hemisphere.
(884.) If we define as “ pole” a spot where the needle
American Points vertica% (which is the signification adopted
pol^.riCan ky Gauss and others), these points do not coin¬
cide with those of greatest intensity. On the 1st
June 1831, Commander Ross (now Sir James
Clark Ross) attained the true magnetic pole in the
North American continent in lat. 70° 5' 17" N., and
long. 96° 45' 48" W. The dip of the needle was
sensibly 90°.
(885.) A third element not less important than Variation
Magnetic and Dip, though more lately brought into notice, is
intensity. intensity 0f garth’s magnetism, and to this Pro¬
fessor Hansteen directed special attention. That the
intensity of the earth’s directive force may be mea¬
sured by counting the oscillations of a suspended
magnet in the same way that a pendulum measures
gravity was known to Graham, Lambert, and others,
towards the middle of the last century ; but the ex¬
ploration of its variation on the earth’s surface was
first attempted by the officers of Laperouse in 1785,
and later by De Rossel. But it was Baron Hum¬
boldt who, at the instigation of Borda,1 undertook
the earliest observations which have had any perma¬
nent influence on this branch of science, and who in
the first years of this century determined the rela- Baron
tive intensity of the earth’s magnetism at Paris and Hum-
at the magnetic equator in South America, to be in boldt’8
the ratio of 1’3482 to 1-0000; 2 * a result which has un^'
become, so to speak, classical, and which the author
considered as the most important result of his jour¬
ney.^ M. Hansteen promoted the same enquiry ex¬
tensively ; he devised a neat and convenient apparatus
for counting the oscillations of the needles, and he
investigated the effects of time and temperature in
altering their magnetism.4 He made numerous ob¬
servations in the north of Europe, and finally under¬
took, between 1827 and 1829 (by the liberality of
the Norwegian parliament or Storthing), an adven¬
turous journey into Siberia, for the purpose of exa¬
mining the “ region of convergence” of the needle in
that quarter. His account of his journey has most M. Erman.
unfortunately not been published; but his compa¬
nion, Professor Adolphe Erman, has given the main
results, together with extensive observations entirely
his own.5 This was the first magnetical expedition
of any magnitude, and of a national character. It
yields in importance to none which have succeed¬
ed it.
The magnetic intensity then increases from the (886.)
neighbourhood of the equator towards the Arctic Distribu-
Regions, and there it has two foci of greatest inten- ?ion of
sity. A similar arrangement occurs in the southern intensity-
hemisphere, and these four points of maximum at¬
traction or convergence of the needle constitute the
“ poles” of Halley and of M. Hansteen. To M.
Hansteen we are indebted for the first good ap¬
proximation to a general chart of the lines of equal
intensity.
The supposed diminution of the magnetic inten- (887.)
sity as we recede from the earth’s surface has been Diminu-
repeatedly made the subject of experiment. The^°n^tic
insulated experiments of Gay-Lussac in a balloon intensity
(630), and of M. Kupffer at Mont Elbroutz, led to with
no conclusive result. From a numerous series of
1 See Kosmos, vol. i., note 159.
2 On the same scale the intensity at London is 1-3720. 3 See Kosmos, ubi. sup.
4 Be Mutationibus Virgce Alagneticce, 1842.
5 See his Lines of Equal Variation, reproduced in the Royal Society’s “ Report on Physics and Meteorology, 1840.”
992
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(888.)
Variations
of mag¬
netic ele¬
ments.
-—1. Secu¬
lar.
(889.)
—2. Diur¬
nal.
(890.)
—3. Irre¬
gular.
(891.)
(892.)
careful observations made in the Alps and Pyrenees
with Hansteen’s apparatus, and studiously corrected
for temperature, the present writer has found a
diminution of one-thousandth part in the horizontal
intensity for a vertical ascent of about 3000 feet.
Such are the general features of the distribution of
the magnetic force upon the surface of the globe. But
from an early period the magnetic elements for the
same place have been known to be variable. Such
deviations from constancy are either—1. Secular ; 2.
Periodic; 3. Irregular. All the three magnetic ele¬
ments (Variation, Dip, and Intensity) probably par¬
take of these changes. The westerly Variation or De¬
clination had till 1818 been increasing in Europe since
the earliest observations. This results from a com¬
plicated movement of the line of No Variation and
its companion curves. While their common centre
or pole in North America has been slowly advancing
towards the East, a considerable portion of the sys¬
tem of curves in this quarter of the globe has been
proceeding in a south-westerly direction nearly in a
line joining Spain with South America, thus produc¬
ing a complicated rotatory motion of the lines of Va¬
riation, of which the first effect was to extinguish the
singular loop in the curve of No Declination (in¬
cluding a space of easterly declination) which is
shown in M. Hansteen's clmxt for 1600 to have
occupied a large part of Western Europe.2 About
1818 the needle began to retrograde towards the
east in this part of Europe. The dip has been dimi¬
nishing in Europe since the earliest observations.
Graham discovered the Diurnal Variation of the
Compass. It occurs in a reversed direction in the
southern hemisphere. Near the equator (as at St
Helena) the needle partakes at one season of the
northern character, at another of the southern, de¬
pending on the position of the sun.
To Baron Humboldt and to Arago we are prin¬
cipally indebted for a knowledge of great and capri¬
cious fluctuations of the magnetic elements occurring
simultaneously over vast regions of the earth. These
have been called magnetic storms.3 They are often
connected with auroral appearances.
Next to Professor Hansteen, science is mainly in¬
debted for the recent great extension of our know¬
ledge of the facts and laws of terrestrial magnetism
to two illustrious German philosophers, Baron Alex¬
ander von Humboldt and the late Professor Gauss.
The name of Alexander von Humboldt is as
widely known as science is cultivated. The ardour Baron
of his love of nature, the comprehensive interest which
he takes in every department of knowledge, and the toldt.
generosity of his disposition, in combination with the
fortunate accidents of an unusually vigorous constitu¬
tion, and an eminent social position, have combined
to place him in the foremost rank of natural philoso¬
phers.
He was born on the 14th September 1769, and (893.)
consequently is now (1856) in his 87th year. He early
was a pupil of Werner in 1791, and devoted consi- travels ^
derable attention to metallurgy. An early longing
for foreign travel seems to have foreshadowed his
future career, but political circumstances were, to¬
wards the close of the last century, eminently un¬
favourable to its accomplishment. His celebrated
journey to Southern and Central America (under¬
taken after the failure of several other schemes) lasted
from June 1799 until August 1804. We may, per¬
haps, be allowed to regret that an impression of the
duty of presenting to the public the results of that
interesting jouraey in their most complete form
should have absorbed the leisure of so many of his
most vigorous years, and should have withheld him
from other and still more important enterprizes.
From 1808 to 1826 Baron Humboldt resided mainly
in Paris, in the most intimate companionship with
Arago, who, though much his junior, has predeceased
him. He then took up his residence at Berlin, in
compliance with the wish of the King of Prussia, and
he soon after delivered there a course of public lec¬
tures on Physical Geography which formed the basis
of his remarkable work entitled Kosmos, the compo¬
sition of which has formed the chief occupation of his
vigorous old age. In 1829 he made a rapid but in¬
teresting journey into Asiatic Russia, important in
its results, yet imperfectly carrying out the ardent
aspiration of his early years to unfold the marvellous
physical peculiarities of the Eastern continent.
Baron Humboldt has contributed more to Physical Hig^t9u^eg
Geography than any other man now living; and that, in phySicai
not only by his individual efforts, but by the direction Geography,
and encouragement which he has given to innumer¬
able travellers and naturalists. His career seems to
have been more closely modelled upon that ot De
Saussure than of any other of his contemporaries or
predecessors. Those branches of Physical Geography
which admit of numerical treatment seem most con¬
genial to him ; and he has left more of the impress
of his personal influence upon the sciences of Meteor-
1 Edinburgh Transactions, vol. xiii.
2 M. Arago gives, no doubt, an erroneous impression in stating that the westerly movement of the line of No Declination has
carried it in 200 years from Paris to Philadelphia. Yet I cannot subscribe to the opinion of his able commentator that the
Loop of No Declination which passed over Europe in the seventeenth century moved eastwards, and may still be traced in Asia
—(British Association, Fifth Report, p. 63; Arago’s Meteorological Essays, translated, p. 330). I conceive that, as stated in the
text, the loop moved south-westwards, became successively an oval and a singular point, and was finally worked out previously
to 1700.
3 In September 1841 a remarkable simultaneous disturbance took place in Canada, Scotland, the Cape of Good Hope, and New
South Wales. Such occurrences are now known to be very common.
Chap. VII., § 8.] ELECTRICITY (MAGNETISM).—BARON HUMBOLDT—GAUSS. 993
Baron ology and Magnetism than upon any others which he
Hum- cultivated. His conception of Isothermal Lines and
Meteoro- treatment of the subject of Climatology in his re-
logy iso- markable paper of 18171 gave a new impulse to the
thermal former subject. His magnetical observations in his
Lines‘ voyage to the Equator have already been adverted to.
Magnetism. Besides this we are indebted to Baron Humboldt for
directing attention to the simultaneous and seemingly
accidental disturbances of the magnetic needle which
take place over vast portions of the area of the globe.
He commenced observations on this subject in con¬
junction with M. Oltmanns as early as 1806 ; and
during his residence in Paris he no doubt encouraged
his friend Arago in those elaborate observations on
the hourly variations of the needle which, to the
irreparable loss of science, remained unpublished
whilst they might have been most useful.2 * In 1829
simultaneous observations were made in Germany
and Russia, and compared by MM. de Humboldt,
Dove, and others, with interesting results.8 It is
probable that the results then obtained instigated
Gauss to the enlarged enquiry to which I shall imme¬
diately refer. M. de Humboldt had already addressed
the Russian Government on the same subject, sug¬
gesting the registration of hourly observations in their
vast territories; and these, the first systematic'ob¬
servations of the kind, have been continued ever
since. The suggestion of “ Term Days” of continuous
registration of the Declination Needle was also due
to Baron Humboldt. In 1836 he addressed the
President of the Royal Society of London on the same
subject, and his letter formed the basis of the exten¬
sive undertakings which have formed the contribu¬
tion of the British Government to this great enquiry.
(895.) Baron Humboldt still lives at Berlin, enjoying the
respect of all who know him, and the distinguished
favour of his Sovereign.
(896.) Carl Friedrich Gauss, late Professor of Astro-
Gtmss. nomy at Gottingen, belonged to that group of cele¬
brated geometers who illustrated the commencement
of this century, and of which he was for some years
the last survivor ; but he too has now passed
away.
(897.) Gauss was born at Brunswick on the 30th April
tost r^and 1777, of humble parents, and was indebted for a
mat hem a-1 liberal education to the notice which his talents pro-
tical works, cured him from the reigning duke. His earliest
original researches were in the theory of numbers.
His Disquisitiones Arithmeticcs were published in
1801, and were as profound and original as they
have always been considered obscure even by those
devoted to such studies. Gauss demonstrated the
possibility of geometrically inscribing a regular poly¬
gon of 17 sides within a circle; the only extension
of geometry in this direction since the time of Euclid.
His Theoria Motus Corporum Ccdestium, published
in 1809, is a very remarkable treatise on the geome¬
trical theory of the planetary orbits; in which it
was shown for the first time how the elliptic ele¬
ments of a heavenly body may be deduced from
three observations only of longitude and latitude,—
an important extension of Newton’s celebrated de¬
monstration in the case of parabolic cometary orbits.
In the same work the method of least squares
(85) was fully unfolded in its applications to astro¬
nomy.
These and many other important labours all con- (898.)
nected with the higher mathematics, had obtained ^nest®arrr‘ggPS
for Gauss an exalted place among the men of science trial mayj
of his time, long before he commenced those re- netism.
searches on Terrestrial Magnetism, in virtue of
which his name is introduced into the present sec¬
tion. It can hardly be doubted, however, that by
these—scarcely begun before he had entered on his
55th year—he will be hereafter chiefly remembered.
His first work on the theory of magnetism4 was pub¬
lished in 1833, and excited very general notice, as it
contained a remarkable application of the Theory of
Attractions to the distribution of magnetism in a
steel bar, a singularly ingenious and rigorous proof
of the primary law of the magnetic force, and like¬
wise a new and practical application of a suggestion Magnetic
thrown out by Poisson, of a method by which the
magnetic directive force of the earth itself may be measure.
expressed in absolute measure, irrespectively of the
constancy of the magnetism in the bar which is in
the first instance used to estimate it. For this purpose
two kinds of observation are required,—1 st, By vibrat¬
ing a needle or bar of known weight and dimensions,
and observing the time of its oscillation, the force
pulling it into the meridian is ascertained in terms
of the ordinary dynamical units. The time depends
jointly on the magnetic force of the earth, and on
that of the bar, or it varies inversely as the product
of the two. 2dly, Another bar, B, is suspended like
the first, A, in the magnetic meridian. A is then
brought to act upon B, so as to draw it permanently
out of the meridian. The position in which B rests
determines the ratio of the magnetic force of the
earth and of the bar A. But quantities whose pro¬
duct and whose ratio are given in known measures, are
also known ; whence the separate intensities of the
earth’s and the bar’s magnetism may be eliminated.5 *
Having thus fairly entered on a career of mag- (899.)
netic experiments, Gauss proceeded, in conjunction
with an experienced physicist of Gottingen, Professor struments.
Wilhelm Weber (420), to invent new apparatus for
1 Memoires d’Arceuil, tom. iii., p. 462. * Posthumously published in his (Euvres.
3 See abstract in Bibliotheque Universelle, Aout 1832.
4 Intensitas vis magneticce terrestris ad mensuram absolutam revocata. Gott. 1833. _ , ,
6 The unit of force to which these intensities are referred is that force (in grains) which acting on unit of mass through unit
of time (a second) generates in it unit of velocity (a foot).
VOL. 1. 6 K
994
MATHEMATICAL AND PHYSICAL SCIENCE.
(900.)
(901.)
(902.)
The Got¬
tingen •
magnetical
observa¬
tions.
(903.)
observing the earth’s magnetism and its changes.
The instruments devised by them were a De¬
clination Instrument and a Bifilar Magnetometer.
The first is a heavy magnetized bar some feet in
length, suspended by a bundle of parallel silk fibres.
It is suffered to place itself in the magnetic meridian,
and the small displacements due to hourly, annual,
or irregular fluctuation, are ascertained by viewing
with a telescope the reflection of a fixed scale of equal
parts placed at some distance in a small mirror
which is attached to the magnetic bar. The bifilar
instrument is for ascertaining changes of intensity in
the earth’s magnetism. It is a bar like the last, sus¬
pended by two parallel threads or wires. By twist¬
ing round the points of double suspension, the bar
is forced by torsion into a position at right angles
to the magnetic meridian, where it is held in
equilibrium by the force of the earth’s magnetism,
and that of the torsion of the wires. Supposing the
latter force to be constant, if the former vary, the
bar will change its position, which is observed by the
mirror and telescope as before.
To these instruments, Professor Lloyd, of Dublin,
added another for measuring the vertical component
of the magnetic intensity. It is a magnet suspended
horizontally on knife-edges like those of a balance.
Its deflection from the horizontal line indicates va¬
riations in the vertical portion of the earth’s mag¬
netism.
The dip is determined in the usual way ; the va¬
riations of dip, however, are ascertained by comparing
the variations of horizontal and vertical intensity.
Gauss did not content himself with suggesting
new forms of apparatus, and recommending them to
others. With the active assistance of M. Weber, he
erected, in 1833, at Gottingen, a magnetic observa¬
tory free from iron (as M. de Humboldt and Arago
had already done on a smaller scale), where he
watched with patience the incessant movements of
the newly-constructed needles or bars. It was from
the same observatory that he sent telegraphic
signals to the neighbouring town, thus showing the
practicability of an electro-magnetic telegraph (856).
He farther instituted an association (magnetischer
Verein), composed at first almost entirely of Ger¬
mans, whose continuous observations on fixed Term-
days extended from Holland to Sicily.* The marvel¬
lous coincidence of the occurrence of even the minute
irregularities of the earth’s magnetism was thus
more fully established.
The Mathematical Theory of Terrestrial Magnetism
of Gauss1 2 3 * * * is intended to replace all arbitrary assump¬
[Diss. VI.
tions whatever as to the distribution of magnetism Gauss’s
m or o\ er the earth. It proposes to express by an ma*tema-
empirical law, involving as little of hypothesis as theory
possible, the direction of the freely suspended mag- trialTag-
netic needle and its directive force at any point of the netism.
earth’s surface, the data being of course derived from
a limited number of observations.
The theoretical assumption with which Gauss (904.)
starts is merely this,—that the elementary force of
magnetism varies inversely as the square of the dis¬
tance, and that it is distributed over the matter of
the terrestrial globe in a way or according to a law
presumed to be entirely unknown.
Following up the methods employed by Laplace (905.)
and others, for representing the attractions of aTheoren?8
sphere or spheroid, he proposes to discover the form attTaTtions.
of that remarkable function (sometimes called the
Potential^ whose differential coefficients express the
resolved components of the total magnetic force.
This quantity V, and also its differential coefficients
(representing the attractions in given directions),
may always be expressed by a series with indetermi¬
nate coefficients, which is known to converge more
or less rapidly; and since the component forces
or attractions are given by observation, the coeffi¬
cients of the terms of the series representing them
may be deduced from a comparison with the data.
The convergency is greatest if the magnetic matter
be disposed towards the centre of the sphere, least if
it reside near its surface.
Retaining quantities of the fourth order, there are (906.)
twenty-four constants, which, rigorously speaking,
may be deduced from complete observations of the
three magnetic elements (888) at only eight stations
anywhere situated on the surface of the globe. With
great patience and skill, Gauss collected as many avail¬
able data as possible for determining these constants
with accuracy, and he thence deduced by calculation
the values of V, those of the declination, horizontal
and vertical force, and that of the dip for all points
of the globe. The beautiful charts which he caused
to be constructed show a remarkable general ac¬
cordance with the complex facts of magnetism as
then known. But in many instances more accurate
data have since been obtained applicable to the im¬
provement of the empirical theory. Perhaps the
most surprising fact which Gauss considers to be
demonstrated is this, that the average amount of
magnetic force associated with every cubic yard of
the earth’s volume (supposing the distribution uni¬
form) is equal to that contained in six saturated steel
bars each a pound in weight.
1 The volumes of their publications, from 1836 to 1839, contain much interesting information on the history of this subject.
2 Allgemeine Theorie des Erdmagnetismus. Leipzig, 1839.
3 See Art. 877. This function V represents the integral —, were dm is the attracting or repelling element, and p its
distance from the point acted on. Gauss represents in his charts the values of the function V at different points of the earth’s
surface. The lines of equal values of V are everywhere perpendicular to the direction of the needle, and the horizontal inten¬
sity is inversely as the distance between two adjacent lines.
(907.)
Great
merit of
Gauss.
His death.
(908.)
Import¬
ance of
national
expedi¬
tions.
(909.)
General
Sabine.
(910.)
British
magnetical
expedi¬
tions.
Chap. VII., § 8.] ELECTRICITY (MAGNETISM).—GENERAL SABINE—SIR J. C. ROSS. 995
On the whole, it is no small praise to say that the
great geometer of Gottingen occupies the same rank
in the theoretical science of terrestrial magnetism as
Kepler did in the theory of astronomy. That a per¬
son devoted for the greater part of his life to pursuits
connected with the most abstract geometry, should
have at last thrown himself with so much zeal into
the practical solution of a complicated experimental
problem, is a circumstance as rare as it is praise¬
worthy. Gauss lived long enough to see his methods
adopted all over the world, and his name honoured
amongst every civilized people. Gauss died at Got¬
tingen (where he had resided since 1807), in great
tranquillity, on the 23d February 1855, in the 78th
year of his age.
But to obtain the data of the empirical theory with
exactness, it is evident that expeditions fitted out ex¬
pressly with accurate apparatus, and directed at once
to many points of the habitable globe, are indispen¬
sable. Powerful governments can alone effect this ;
and to Baron Humboldt is due (as has been shown)
the praise of having vigorously pressed the import¬
ance of these upon the governments of England and
of Russia. The vast marine resources of the former,
and the peculiar magnetic interest of the stupendous
Asiatic territory of the latter, rendered their co¬
operation highly important. In the result, Great
Britain has accomplished by far the larger share of
this vast enterprise.
To Major-General Edward Sabine, of the Royal
Artillery, is mainly due the judicious management of
these magnetic explorations, and the speedy and skilful
publication of their interesting results. During the
course of an active life he has enjoyed opportunities
of making extensive observations with magnetic ap¬
paratus and with the pendulum (238) throughout a
great range of latitude. His experiments (carried on
principally between the years 1819 and 1826) were
made in Brazil, the coast of Guinea, Spitzbergen, and
Arctic America. His observations on magnetic inten¬
sity are particularly valuable, and first indicated the
position of a region of maximum intensity in North
America considerably to the south of the magnetic
pole as indicated by the dipping needle. To him
we also owe a valuable Intensity Chart of the Globe,
and a Magnetic Survey of the British Islands, pub¬
lished in the reports of the British Association for
1836 and the two following years.
But his efforts in promoting and directing the
system of national magnetical research set on foot at
Baron Humboldt’s instigation are of still greater
importance, to which, in its earlier stages, the exer¬
tions of Dr Lloyd (550) were also of essential service.
Although seconded by young, able, and enthusiastic
officers of the service to which General Sabine be¬
longs, the difficulty of starting simultaneously sys¬
tematic observations (with instruments new and little
understood, and dispersed to the widest possible ex¬
tent over the surface of the globe), was evidently very
great. Canada, St Helena, the Cape of Good Hope,
and Van Diemen’s Land, were selected for primary
stations ; and the vastly voluminous results of hourly
or two-hourly observations of numerous instruments
continued year by year came pouring in to the central
establishment at Woolwich under General Sabine’s
presidency. Besides these, several nautical expedi¬
tions were fitted out for similar purposes, the most
important of which was sent in 1840 under the direc¬
tion of Sir James Clark Ross to approach as nearly Captain
as might be to the Antarctic Pole. This voyage, whe- ^
ther in respect of the spirit of adventure displayed,
the wonderful character of the natural objects re¬
vealed by it for the first time to human view, or the
importance of the scientific results obtained, may
rank with any of our memorable polar expeditions.
By the aid of an ingenious instrument contrived by
Mr Fox, trustworthy magnetical observations were
made on dip and intensity (as well as on declina¬
tion) even in the open sea, and thus the area contri¬
buting to our knowledge of the earth’s magnetism
was vastly increased. The results of these researches
properly reduced have been gradually laid before the
world by General Sabine in a series of memoirs of
the utmost interest, contained in the Philosophical
Transactions from 1840 to the present time.
With regard to the geographical phenomena of (911.)
magnetism, it may now be inferred almost with cer- Geogra-
tainty that the position of the Antarctic magnetic pole
is in a region hitherto inaccessible, and to the south curves 0f
of New Holland, placed somewhere near longitude intensity.
150° E., and probably not within 17° of the pole of
the earth, a latitude which was reached by Sir James
Ross in a longitude somewhat farther east.1 It ap¬
pears also that in the southern as in the northern
hemisphere there are two centres of greatest intensity,
round which the curves of equal intensity form ovals,
and afterwards loops like lemniscates. The stronger
magnetic centres of each hemisphere are near, though
apparently not coincident with, the two proper mag¬
netic poles. The following numbers approximately re¬
present on a scale of absolute intensity (898), in which
the grain, the foot, and the second are units, the
magnetic force at the four centres just mentioned;
the second column contains the corresponding values
on Baron Humboldt’s scale, mentioned in Art. 885.
Absolute.
In North America, . . . 14,2
In Siberia, 13’3
South from New Holland, . 15,14
The other Antarctic centre, 14‘9
On Humboldt’s Scale.
1-88
1- 76
2- 00
T97
The absolute intensity at St Helena, which is not far
1 See General Sabine’s Charts in Phil. Tram., 1844.
996
MATHEMATICAL AND PHYSICAL SCIENCE.
[Diss. VI.
(912.)
European
magnetical
observa¬
tories.
(913.)
Depen¬
dence of
magnetic
periods on
the sun
and moon.
from the minimum, is 6*4. These observations also
fully confirm the progressive motion of the whole
system of magnetic lines on the surface of the
globe.
In Europe national, and even private, observa¬
tories have contributed largely to our knowledge of
the laws of magnetism. Among these observatories
may be mentioned Greenwich, Dublin, Makerstoun
in Scotland, Munich, Prague, Brussels, St Peters-^
burg, and the numerous other Russian stations. At
Greenwich and at Kew, near London, the automatic
registration of magnetical and meteorological instru¬
ments, by means of photography, was introduced by
Mr Brooke and Mr Ronalds. It would be impossi¬
ble in this place to give even a summary of the re¬
sults obtained from these and the Colonial estab¬
lishments. Besides the valuable deductions by
General Sabine already referred to (910), the careful
analysis of the formal laws of magnetism obtained at
their respective observatories byM.Lamont, M.Kreil,
and Mr Broun (Sir Thomas M. Brisbane’s observer),
merit special notice.
The primary cause of the earth’s magnetism re¬
mains involved in the greatest doubt. That it is due
to electric currents, and not to permanent magnet¬
ism, is at least probable; and it is likely that these
currents may, in part at least, be of a thermo-electric
character, or the effects may possibly depend upon
the direct demagnetising influence of temperature, as
Dr Faraday supposes (830). The secular magnetic
changes will probably ever remain the most unac¬
countable. The greater portion of those which are
obviously periodic seem to depend upon the position
and efficiency of the sun in its apparent diurnal and
annual course, having their crises at certain hours of
the day, and certain seasons of the year. It is un¬
derstood that the most recent researches leave little
doubt as to a like influence arising from the moon’s
position.1 It appears also to be indicated (although
the induction is perhaps yet incomplete) that the
diurnal changes, and also those of a capricious and
irregular character (magnetic storms), have a period
of greatest and least intensity of fluctuation extending
to about ten years, a minimum having occurred in
1843, and a maximum in 1848. This nearly coin¬
cides with a period of greatest and least abundance
of the solar spots detected by M. Schwabe, and it is
possible that there is a real connection between the
phenomena. The first recognition of a ten-year mag¬
netic period appears to be due to M. Lament, that of
a probable concurrence with the frequency of solar
spots to General Sabine.
1 While correcting the press of this page, I have received an interesting paper by General Sabine {Phil. Trans., 1856), in
which the dependence of the various magnetic elements on the moon’s diurnal place is deduced from a very large number of
observations. The change of declination in the course of th&'lunar day amounts to above 38''.
Addition to Art. 283, page 860.
The following is a continuation of the list previously given of the small Planets:
No.
36
37
38
39
40
41
42
Name.
Atalanta
Fides
Leda
Lajtitia
Harmonia
Daphne
Isis
Date of Discovery.
1855 Oct. 5
Oct. 5
1856 Jan. 12
Feb. 8
March 31
May 22
May 28
Discoverers.
Goldschmidt.
Luther.
Chacornac.
Chacornac.
Goldschmidt.
Goldschmidt.
Pogson.
'
X
t