ELEMENTS 
 
 PHILOSOPHY, 
 
 ARRANGED UNDER THE FOLLOWING 
 
 HE ADS t 
 
 Matter and Motion, 
 The Universe, 
 The Solar System, 
 The Fixed Stars 
 
 e xe tars, 
 
 The Earth considered as a Planet, 
 The Atmosphere, 
 
 Meteors, 
 
 Springs, Rivers, and the Sea, 
 
 Fossils, 
 
 Plants, 
 
 Animals., 
 
 The Human Frame, 
 
 And 
 THE HUMAN UNDERSTANDING, 
 
 T see a mighty arm, by man unseen, 
 'Resistless-, not to be controlled, that guides, 
 " In solitude of unshar'd energies, 
 u All these thy ceaseless miracles, O world!" 
 
 C. LAME- 
 
 NEW-rORK: 
 
 Printed by D. & G. Bruce, 
 FOR J. QSBQRN, BOOKSELLER, 13 PARK, 
 
 1808, 
 

 CONTENTS;" 
 
 Page 
 
 Ckap. I. Matter and Motion . , . 11 
 
 II. The Universe 24> 
 
 III. The Solar System 3f 
 
 IV. The Fixed Stars 57 
 
 V. The Earth considered as a Planet . . 68 
 
 VI. The Atmosphere 90 
 
 VII. Meteors . . . , 105 
 
 VIII. Springs, Rivers, and the Sea 124 
 
 IX. Fossils 141 
 
 X. Plants 177 
 
 XI. Animals 200 
 
 XII. The Human Frame 234 
 
 XIII. The Human Understanding ...... ^260 
 
 984 
 
PREFACE. 
 
 IN an age like the present, when 
 the growth of every production con- 
 ducive to the interests of morality, and 
 a more extensive knowledge of the 
 Creator through the medium of his 
 
 O ' y 
 
 tvorks, is recommended and publicly 
 encouraged, hut little need be offered 
 by way of apology for the present 
 Compilation. One important object 
 of the following pages was to present ^ 
 in a very compact and comprehensive 
 form, an interesting and connected 
 account of those laws and operaiions 
 in the material world > which > under 
 the elaborate pens of philosophical 
 authors, cover an extent of scientific 
 ground too enlarged for the commer- 
 cial and labouring individual to tra- 
 vel over ; but more particularly has 
 this little compendium been arranged 
 for the juvenile inquirer, who either 
 A 
 
PREFACE. 
 
 from a premature wish to anticijh 
 the result of deep calculations, or from, 
 other contingent occupations, would 
 have a general, yet clear, idea of ob- 
 jects, which zvithout the aid of philo- 
 sophy he cannot understand. To en- 
 able him to accomplish this desirable 
 end, the following pages are, as far 
 as possible, divested of the technical 
 difficulties which but too often form 
 impenetrable barriers to the expan- 
 sion of the rising mind. While, how- 
 ever, they endeavour to exhibit in a 
 -^amiliar manner that chain of con- 
 nexion which binds and unites all na- 
 ture, they will by no means supersede 
 an encouragement to penetrate into 
 those sciences whence the axioms, laws, 
 and calculations which relate to mat- 
 ter and motion are ascertained.. 
 
 Having notified the design of this 
 little manuel, it is unnecessary to en- 
 force the importance of the. subject of 
 which it treats. No employment sure- 
 
PREFACE. 7 
 
 hj yields so rich a 'harvest of instruc- 
 tion and delight to a rational being 
 as that of surveying the wonderful 
 works of tlic Great Creator -, as dis- 
 played in the various parts of the 
 universe. Such employment is a source 
 of never-failing satisfaction to per- 
 sons of every age ; and it is only by 
 acquiring a knowledge of nature, and 
 observing the contrivance and skill 
 conspicuous in every department of 
 creation, that we are enabled to form 
 an adequate idea of the attributes 
 and character of the Supreme Being. 
 In proportion as we attain a know- 
 ledge of the objects around us they 
 become interesting and important. 
 That which to the careless and un- 
 enlightened spectator , appears solita- 
 ry and detached, having no other con- 
 nection with the rest of the universe 
 but the shadowy andjleeting relation 
 of co-existence, zvill, to him who takes 
 i glimpse into the general economy 
 
$ PREFACE* 
 
 of nature* declare themselves to l>e 
 ports of a great and harmonious 
 whole, connected by general laws, and 
 tending fo one general and beneficent 
 J);trp-jse> and cannot fail of impres- 
 sing him with a wish to co-operate in 
 tins glorious plan, by acting worthy 
 of the place he holds among the works 
 
 &GO& 
 
 Tn as is the study of nature calcu- 
 lated to eral 1 the mind, and reduce 
 the sinn of human pride and igno- 
 ? ' - , and ccmes in aid of that self- 
 abasement which the great duties of 
 Christianity impose, hy teaching man 
 that, though he stands a pinnacle of 
 power, and grasps in intellect all the 
 prodigious works of 'creation, he is but 
 a link in an immeasurable chain that 
 serve* to suspend and give motion to 
 the zoorks of Him who 
 
 Connects each being, greatest with the least, 
 Made beast in aid of man, and man of beast. 
 
 Nor is it as a moral agent only 
 
PREFACE. 
 
 tnat man is benefited by a knowledge 
 of natural philosophy ; it teaches him 
 to employ the powers of nature to the 
 greatest advantage for the embellish- 
 ment and comfort of life, and extends 
 his empire over the material universe. 
 
 Knowledge of this kind, therefore, 
 is the most valuable that man can ac- 
 quire: it enriches his life with conve- 
 niences, enlarges his views, and lays' 
 a foundation for the most rational 
 and exalted piety. * ( The universe 
 (says Boyle) is the magnificent tem- 
 ple of its great Author ; and man is 
 ordained, by his powers and qualifi- 
 cations, the high-priest of nature, to 
 celebrate divine service in this temple 
 of the universe." 
 
 Let him then, aspiring to the dig- 
 nity of his station, assisted by the 
 writings of modern authors, devote 
 his noblest powers to the investigation 
 of the laws of nature ; and evince that 
 he is not in vain given ability to be 
 
1O PREFACE* 
 
 wiser than the fowls of heaven, and 
 to have more understanding than the 
 beasts which perish. 
 
ELEMENTS 
 
 NATURAL PHILOSOPHY, 
 
 CHAP. I. 
 
 Of Matter and Motion. 
 
 MATTER is an extended solid* sub- 
 stance ; which being comprehended un- 
 der distinct surfaces, makes so many par* 
 ticular distinct bodies. 
 
 * Solidity is not here considered as opposed to 
 fluidity, but as that property which every body 
 possesses of not permitting' any other substance to 
 occupy the same place with it at the same time ; 
 so that both water and air, and every other fluid, 
 are equally solid, in this sense of the word, with 
 the hardest body. By solidity, in common lan- 
 guage, is understood the property of not being* 
 easily separated into parts ; and therefore the 
 reader must be careful not to confound the mean- 
 ing- of the popular with the philosophical terro* 
 
1 2 Matter and Motion. 
 
 Motion is so well known by the sight 
 and touch, that to use words to give a 
 clearer idea of it would be in vain. 
 
 Matter, or body, is indifferent to mo- 
 tion or rest. 
 
 There is as much force required to 
 put a body, which is in motion, at rest ; 
 as there is to set a body, which is at rest, 
 into motion. 
 
 No parcel of matter can give itself ei- 
 ther motion or rest ; and therefore a bo- 
 dy at rest will remain so eternally, ex- 
 cept some external cause puts it in mo- 
 tion ; and a body in motion will move 
 eternally, except some external cause 
 stops it. 
 
 A body in motion will always move 
 on in a straight line, unless it be turned 
 out of it by some external cause ; because 
 a body can no more alter the determina- 
 tion of its motion than it can begin it, 
 alter or stop its motion itself. 
 
 The velocity of motion is estimated 
 by the time employed in moving over a 
 certain space, or by the space moved 
 over in a certain time. The less the time, 
 and the greater the space moved over, the 
 greater is the velocity ; on the contrary, 
 
Matter and Motion. 13 
 
 the greater the time,and the less the space 
 moved over, th*. less is the velocity* Ev- 
 ery body in motion must have a determi- 
 nate velocity. To ascertain the degree 
 of this swiftness or velocity, the space 
 run over must be divided by the time. 
 For example, suppose a body moves over 
 1000 yards in 10 minutes, its velocity 
 will be 100 yards per minute, because 
 100 is the quotient of 1000, divided by 
 10. If we would compare the velocity 
 of twu bodies A and B, of v.hich A 
 moves over 54 yards in 9 minutes, and 
 B 96 yards in 6 minutes, the velocity of 
 A will he to that of B, in the proportion 
 of 6 (the quotient of 54 divided by 9) to 
 16 (the quotient of 96 divided by 6.) 
 
 To know the space run over, the velo- 
 city must be multiplied by the time ; for 
 it is evident, that if either the velocity or 
 the time be increased, the space run over 
 will be greater. If the velocity be doub- 
 led, then the body will move over twice 
 the space in the same time ; or if the 
 time be twice as great, then the space 
 will be doubled : but if the velocity and 
 time be both doubled, then will the 
 be four times as great, 
 
14 Matter and Motion. 
 
 It follows from this, that when two 
 bodies move over unequal spaces in un- 
 equal times, their velocities are to each 
 other as the quotients arising from divi- 
 ding the spaces run over by the times. 
 If two bodies move over unequal spaces 
 in the same time, their velocities will be 
 in proportion to the spaces passed over. 
 And if two bodies move over equal spa- 
 ces in unequal times, then their respec- 
 tive velocities will be inversely as the 
 time employed ; that is, if A in one min- 
 ute, and B in two minutes, run over 10O 
 yards, the velocity of A will be to that 
 "of B as 2 to 1 . 
 
 It appears, as far as human obervation 
 reaches, to be a settled law of nature, 
 that u all bodies have a tendency, attrac- 
 tion, or gravitation towards one another." 
 
 The same force applied to two differ- 
 ent bodies, produces always the same 
 quantity of motion in each of them. For 
 instance, let a boat, which with its lad- 
 ing is one tun, be tied at a distance, to 
 another vessel, which with its lading is 
 twenty-six tuns ; if the rope that ties 
 tliem together be pulled either in the less 
 or bigger of these vessels, the 
 
Matter and Motion. 15 
 
 two, in their approach one to another, 
 ivijl move twenty-six foot, while the oth- 
 er moves but one foot. 
 
 Wherefore the quantity of matter in 
 the earth being twenty-six times more 
 than in the moon, the motion in the moon 
 towards the earth, by the common force 
 of attraction, by which they are impelled 
 towards one another, will be twenty-six 
 times as fast as in the earth ; that is, the 
 moon will move twenty-six miles towards 
 the earth, for every mile the earth moves 
 towards the moon. 
 
 This attraction is the strongest, the 
 nearer the attracting bodies are to each 
 other ; and in different distances of the 
 same bodies, is reciprocally in the dupli- 
 cate proportion of those distances. For 
 instance, if two bodies, at a given dis- 
 tance, attract each other with a certain 
 force, at half the distance, they will at- 
 tract each other with four times that 
 force ; at one third of the distance, with 
 nine times that force ; and so on. 
 
 Two bodies, at a distance, will put one 
 another into motion by the force of at- 
 traction ; which is inexplicable by us, 
 though made evident to us by experience, 
 
16 Matter and Motion* 
 
 and so to be taken as a principle in na* 
 tural philosophy. 
 
 Supposing then the earth the sole bo- 
 dy in the universe, and at rest ; if God 
 should create the ir.oon, at the same dis- 
 tance that it is now from the earth, the 
 earth and the moon would presently be- 
 gin to move one towards another in a 
 straight line, by this motion of attraction 
 or gravitation. 
 
 If a body, that by the attraction of 
 another would move in a straight line 
 towards it, receives a new motion any 
 ways oblique to the first, it will no longer 
 move in a straight line, according to ei- 
 ther of those directions, but in a curve, 
 that will partake of both ; and this curve 
 will differ, according to the nature and 
 quantity of the forces that concurred to 
 produce it; as, for instance, in many ca- 
 ses it will be such a curve as ends when* 
 it began, or recurs into itself; that is, 
 make up a circle, or an ellipsis, or oval 
 very little differing from a circle. 
 
 Attraction may be divided, with res- 
 pect to the law it observes, into two kinds. 
 That which takes place at a sensible, dis- 
 tance^ and that which does not extend to 
 
Matter and Motion* 1 7 
 
 sensible distances. The first is called 
 the attraction of gravity, or, by mathe- 
 maticians, the centripetal force. 
 
 This is the species of attraction whose 
 laws we have endeavoured to elucidate. 
 It is one of the most universal principles 
 In nature. We see and feel it operate in 
 bodies near the earth, and find by obser- 
 vation that the same power (i. e. a power 
 which acts in the same manner, and by 
 the same rules, viz. always proportionally 
 to the quantities of mattter, and inverse- 
 ly as the squares of the distances) does al- 
 so obtain in the moon, and the other plan- 
 ets, both primary and secondary, as well 
 as in the comets ; and even that this is 
 the very power by which they are all re- 
 tained in their orbits. This mighty prin- 
 ciple fornixS the earth into a round and 
 dense ball, holds every thing animate and 
 inanimate to its surface, and makes its 
 whole surface its general top. 
 
 .From this attraction arises all the mo- 
 tion, and consequently all the mutation, 
 in the great world. By this heavy bodies 
 descend, and light ones ascend ; by this 
 projectiles are directed, vapours and ex- 
 halations rise, and rains fall -, by this 
 B 
 
1 8 Matter and Motion. 
 
 rivers glide, the ocean swells, the air 
 presses, &c. 
 
 2d. That which does not extend to 
 sensible distances. Such is found to ob- 
 tain in the minute particles of which 
 bodies are composed, attracting each oth- 
 er at or extremely near the point of con- 
 tact, with forces often much superior to 
 that of gravity, but which at any distance 
 decrease much faster than the power of 
 gravity. This power a late ingenious 
 author calls the attraction of cohesion, 
 as being that by which the atoms or in- 
 sensible particles of bodies are united into 
 sensible masses. 
 
 The laws of motion, percussion, &c* 
 in sensible bodies, under various circum- 
 stances, as falling, projected, &c. do not 
 reach those more recluse intestine mo- 
 tions in the component particles of the 
 same bodies, on which depend the chan- 
 ges in the texture, colour, properties,. 
 &c. of bodies. So that our philosophy, 
 if it were only founded on the principle 
 of gravitation, and even carried as far as 
 this would kad us, would still be very 
 deficient. But, besides the common law* 
 of sensible masses, the minute parts they 
 
Matter and Motion. 19 
 
 are composed of are found subject to 
 some others, which have but lately been 
 noticed,, and are even yet imperfectly 
 known 8 Newton himself, to whose hap- 
 py penetration we owe the hint, limits 
 liimself with establishing that there are 
 such motions in the minima natures, and 
 that they flow from certain powers or 
 forces, not reducible to any of those in 
 the great world, and from hence he ac- 
 counts for an infinity of phenomena, oth- 
 erwise inexplicable, to which the princi- 
 ple of gravity is inadequate. Thus, adds 
 Sir Isaac, "will nature be found very 
 conformable to herself, and very simple; 
 performing all the great motions of the 
 heavenly bodies by the attraction of grav- 
 ity, which intercedes those bodies, and 
 almost all the small ones of their parts, 
 by some other attractive power diffused 
 through their particles. Without such 
 principles, there never would have been 
 any motion in the world ; and without 
 the continuance of it, motion would soon 
 perish, there being otherwise a great de- 
 crease or diminution, of it, which is only 
 supplied by these active principles." 
 By the attraction of cohesion are form- 
 
2O liter and Motion. 
 
 cd stones, metals, woods, salts, and eve- 
 ry thing that may be denominated body. 
 The effects of solders, glue, cements, &c. 
 are all from the same cause. So jewels, 
 hard stones, stalactites, petrifactions, por- 
 celain, pottery, bricks, flags, glass, ce- 
 ments, artificial stones, and plastic earthy 
 compositions, which preserve their figure 
 in drying, all are children of this great 
 agent ; and as this power is much great- 
 er in some bodies than in others, there 
 arises an infinite variety in the strength, 
 the weight, the texture, &c. of metals, 
 stones, &c. for we have powerful reasons 
 to believe that the original particles of all 
 matter are of the same weight ; and that 
 it is this principle that makes thegreat dif- 
 ference in their specific weight. To minds 
 not used to philosophical investigation, it 
 must appear a bold assertion to say, that 
 the particles of gold are not one whit hea- 
 vier than the particles of cork ; but expe- 
 riment and observation shew this to be 
 really the case. 
 
 The grand antagonist principle of the 
 attraction of cohesion is fire (or caloric 
 in the new language of chemistry.) These 
 two opposing powers keep nature in a state 
 
Matter and Motion. 21 
 
 f perpetual motion. When the attractive 
 force is strongest, the body continues in a 
 state of solidity ; but if, on the contrary, 
 heat has so far removed the particles of it, 
 as to place them beyond the sphere of at- 
 traction they lose their adhesion, and the 
 body becomes fluid. Water, when cooled 
 below 32 degrees of Fahrenheit's ther- 
 mometer, becomes solid, and is called 
 ice. Above that temperature, its parti- 
 cles not being held together, it becomes 
 liquid ; but when raised to 212 degrees, 
 its particles give way to the repulsive 
 power of fire, and, flying off, assume an 
 aeriform state, called steam ; the same 
 may be affirmed of all bodies in nature, 
 for even diamonds, the hardest substance 
 we know, are capable of being dispersed 
 by a common culinary fire* 
 
 It may therefore be considered as an 
 axiom, that all bodies are capable in cer- 
 tain circumstances, of the three states of 
 !$gtidity\ fluidity^ and gas. 
 
 The atoms of which bodies are formed, 
 are concealed from us by their minute- 
 ness, and though they are the active parts 
 of matter, and the great instruments of 
 Bature,on which depend all its operations* 
 B2 
 
32 Matter and Motion. 
 
 we can form no idea of them, for whether 
 we view animate or inanimate matter, 
 the corpuscles of which it is formed ^re 
 so infinitely small, as not only to escape 
 the scrutiny of the highest magnifying 
 powers in glasses, but even imagination 
 itself is incapable of forming an idea of 
 an original particle of matter : One pound 
 of gold is capable of covering a wire that 
 will circumscribe the globe, nay, so infi- 
 nite is this divisibility that Lewenhoeck 
 discovered more living animalcules in the 
 milt of on^ single cod-fish than there are 
 jnen, women, and children on the face of 
 the earth ! and those so small that many 
 thousands may stand upon the point of a 
 needle. And if we suppose that these 
 animalculae are furnished with blood, like 
 other animals, and if the globules of their 
 blood bear the same proportion to their 
 bulk as those of a man bear to his body, it 
 may be proved, that the smallest visible 
 grain of sand would contain more of these 
 globules than 10,256 of the largest moun- 
 tains in the world would contain grains 
 of sand. 
 
 When we consider these tilings we 
 seem to look down into infinity j and as. 
 
Matter and Motion. 23 
 
 in the contemplation of the starry heavens, 
 we can conceive no term to the extension 
 of space ; so, in regarding the minute 
 parts of creation we see no end to the 
 divisibility of matter. We are lost in 
 wonder when we attempt to comprehend 
 either the vastness or the minuteness of 
 creation, and are necessarily made to 
 feel that it belongs only to the one great 
 and incomprehensible Power, who work- 
 eth in ways past finding out. 
 
24 The Universe* 
 
 CHAP. II. 
 
 Of the Universe. 
 
 TO any one, who looks about him in 
 the world, there at:e obvious several dis- 
 tinct masses of matter, separate from one 
 another ; some whereof have discernable 
 motions. These are the sun, the fixed 
 stars, the comets, and the planets, amongst 
 which this earth, which we inhabit, is 
 one. All these are visible to our naked 
 eyes. 
 
 Besides these, telescopes have discov 
 ered several fixed stars, invisible to the 
 naked eye ; and several other bodies mo- 
 ving about some of the planets ; all which 
 were invisible and unknown, before the 
 use of prospective glasses was found. 
 
 The vast distances between these great 
 bodies, are called intermundane spaces ; 
 in which though there maybe some fluid 
 matter, yet it is so thin and subtile ; and 
 there is so little of that in respect of the 
 
The Universe. i25 
 
 great masses that move m those spaces, 
 that it is as much as nothing. 
 
 These masses of matter are, either lu- 
 minous, or opaque or dark. 
 
 Luminous bodies, are such as give 
 light of themselves ; and such are the 
 sun, and the fixed stars. 
 
 Dark or opaque bodies, are such as 
 emit no light of themselves, though they 
 are capable of reflecting it, when it is 
 cast upon them from other bodies : and 
 such are the planets. 
 
 There are some opaque bodies, as for 
 instance the comets, which besides the 
 light, that they may have from the sun, 
 seem to shine with a "light that is nothing 
 else but an accension, which they receive 
 from the sun, in their near approaches to 
 It, in their respective revolutions. 
 
 The fixed stars are so called, because; 
 they always keep the same distance one 
 from another. 
 
 On a view of the visible system of na- 
 ture, by us called the universe, the grand- 
 est and most admired object is the great 
 luminary of day. Its splendour, its heat, 
 its beneficial influence have always 
 
26 The Universe. 
 
 excited the particular attention of the hu- 
 man species, and have obtained the ado- 
 ration of all those nations which have not 
 been blessed with revelation. 
 
 Those who are not accustomed to as- 
 tronomical calculation, will be surprized 
 at the real magnitude of this luminary ; 
 \vhich, on account of its distance from us, 
 appears to the eye not much larger than 
 the moon, which is only an attendant on 
 our earth. When looking at the sun, 
 we are viewing a globe, whose diameter 
 is 890,000 English miles ; whereas the 
 earth is no more in diameter than 7,97O 
 miles : so that the sun is about 1,392,500 
 times bigger than the earth. Thus as it 
 is the fountain of light and heat to all the 
 planets, so it also far surpasses them in 
 its bulk. 
 
 . The sun has several spots, which are 
 visible on its surface. These spots were 
 entirely unknown before the invention of 
 telescopes, though they are sometimes 
 of sufficient magnitude to be discerned by 
 the naked eye. There is a great variety 
 in their magnitudes ; some have been so 
 large, as by computation to be capable of 
 covering the continents of Asia and Af* 
 
The Universe. 27 
 
 rica ; nay, the whole surface of the earth, 
 or even five times its surface. 
 
 The nature and formation of the solar 
 spots have been the subject of much 
 speculation and conjecture. The latest 
 observations on them, and on the nature 
 and construction of the sun, are those of 
 Dr. Herschel : he considers the sun as 
 a most magnificent habitable globe, sur- 
 rounded by a double set of clouds. Those 
 which are nearest its opaque body, are 
 less bright, and more closely connected 
 together than those of the upper stratum, 
 which form the luminous apparent globe 
 nve behold. This luminous external mat- 
 ter is of a phosphoric nature, havingseve- 
 ral accidental openings in it, through 
 V/hich we see the sun's body, or the more 
 opaque clouds beneath. Those openings 
 form the spots we see. 
 
 Next to the sun, the moon is the most 
 splendid and shining globe in the hea* 
 %-ens ; and by dissipating, in seme meas- 
 ure, the darkness and the horrors of the 
 night ; subdividing the year into months, 
 and regulating the flux and reflux of the 
 sea, she not only becojnes a pleasing, but 
 
28 The Universes 
 
 a welcome object ; affording much for 
 speculation to the contemplative mind, 
 and of real use to the navigator, the 
 traveller, and the husbandman. The 
 Hebrews, the Greeks, the Romans, and in 
 general, all the ancients, used to assem- 
 ble at the time of the new moon, to dis- 
 charge the duties of piety and gratitude 
 for its manifold uses. 
 
 When we view this attendant on our 
 earth in its nightly course, we seldom 
 form an adequate idea either of its mag- 
 nitude, or its motion. While it seems to 
 take some hours in getting half a yard 
 from a star which it touched, we never 
 reflect that this is an immense mass of 
 matter, of 218O miles in diameter, dri- 
 ving through the heavens at the rate of 
 considerably more than two thousand 
 miles an hour, which is more than double 
 of that with which a ball is shot off from 
 the mouth of a cannon. 
 
 The face of the moon is greatly diver- 
 sified with inequalities, and parts of dif- 
 ferent colours, some brighter, and some 
 darker than the other parts of her disk. 
 When viewed through a telescope, her 
 face is evidently diversified with hills and 
 valleys : and the same is also shewn by 
 
The Universe. .29 
 
 the edge or border of the moon appearing 
 jagged, when so viewed, especially about 
 the confines of the illuminated part when, 
 the moon is either horned or gibbous. 
 
 M. Schroeter, of the Royal Society o 
 Gottingen, in the year 1792, seems to have 
 taken great pains to investigate the truth 
 of this matter, i According to him, the 
 surface of the moon appears to be much 
 more unequal than that of our earth ; and 
 these inequalities have great variety both 
 in form and magnitude. There are large 
 irregular plains, on which are observed 
 long and narrow strata of hiljis running in 
 a serpentine direction : some of the moun- 
 tains form extensive chains ; others, which 
 are in general the highest, stand alone, 
 and are of a conical shape : some have 
 craters ; others form a circular ring in- 
 closing a plain. The most lofty moun- 
 tain on the surface of our globe is suppo- 
 sed to be Chimboraco, which is not twen- 
 ty thousand feet in height : but there are 
 many in the moon which are much high- 
 er ; that which is distinguished by the 
 name of Leibnitz^ is not less than 25 3 OOO 
 feet. 
 
 C 
 
30' The Universe. 
 
 The craters of the moon are circular, 
 and surrounded with an annular bank of 
 hills : they are remarkable for their 
 width, many of them being from four to 
 fifteen geographical miles in diameter : 
 some are not deeper than the level of the 
 moon's surface ; others are 9000, 12,000, 
 and 15,000 feet in depth ; that of one 
 which M. Schroeter calls Bernoiiilli, is 
 above 18,000 feet. 
 
 On the face of the moon are likewise 
 volcanoes \vhich appear to the observer 
 as lighted coals, and illuminate the neigh- 
 bouring mountains. 
 
 With respect to the nature and con- 
 ' struction of the moon and the probability 
 of its being inhabited, Dr. Herschel, in 
 his papers published in the Philosophical 
 Transactions of 1795, concludes, after 
 tracing the great similarity between it and 
 the earth, as follows : u There seems on- 
 ly to be wanting, in order to complete 
 the analogy, that it should be inhabited.- 
 To this it may be objected, that we per- 
 ceive no large seas in the moon ; that its 
 atmosphere (the existence of which has 
 even been doubted by many) is extreme- 
 ly rare, and unfit for the purposes of ani* 
 
'The Universe* 31 
 
 mal life ; that its climates, its seasons, 
 and the length of its days, totally differ 
 from ours ; that without dense clouds 
 (which the moon has not) there can be 
 no rain ; perhaps no rivers, no lakes. In 
 short, that r notwithstanding the similarity 
 which has been pointed out, there seems 
 to be a decided difference in the two pla- 
 nets we have compared. My answer to 
 this will be, that that very difference 
 which is now objected will rather strength- 
 en the force of my argument than lessen 
 its value ; we find, even upon our globe, 
 that there is the most striking difference 
 in the situation of the creatures that live 
 upon it. While man walks upon the 
 ground, the birds fly in the air, and fishes 
 .swim in water ; we can certainly not ob- 
 ject to the conveniences afforded by the 
 moon, if those that are to inhabit its re- 
 gions are fitted to their conditions as well 
 as we on this globe are to ours. An ab- 
 solute or total sameness seerns rather to 
 denote imperfections, such as nature ne- 
 ver exposes to our view ; and, on this ac- 
 count, I believe the analogies that have 
 been mentioned fully sufficient to estab- 
 lish the high probability of the moon's 
 being inhabited like the earth." 
 
32 The Universe. 
 
 Lastly of the earth on which we dwell, 
 Speck as this may appear in the im- 
 mensity of creation, it is nevertheless to 
 us of the highest importance; we only 
 wish to obtain a knowledge of other pla- 
 ne ts % and systems, that we may find out 
 their relation to this, and from thence 
 learn our connection with the universe at 
 large. 
 
 The external part of the earth either 
 exhibits inequalities, as mountains and 
 valleys ; or it is plane and level ; or dug 
 in channels, fissures, beds, &c. for rivers, 
 lakes, seas, &c. These inequalities in 
 the face of the globe most naturalists 
 suppose have arisen from a rupture or 
 subversion of the earth, by the force ei- 
 ther of the subterraneous fires or waters. 
 The earth in its natural and original state, 
 It has been supposed by Des Cartes, and 
 after him Burnet, Steno, Woodward, 
 Whiston and others, was perfectly round, 
 smooth, and equable ; and they account 
 for its present rude and irregular form, 
 principally from the great deluge ; but 
 from whatever cause those inequalities 
 may have arose, or at what period, they 
 seem a necessary part of the econonr 
 
The Universe* SS 
 
 nature. It is the intermediate space be- 
 tween the mountain's top and the sea- 
 shore that forms the habitation of plants 
 and animals. While there is sea-shore 
 and high ground, there is that which is 
 required in the system of the world ; 
 take that away, and there would remain 
 an aqueous globe in which the world 
 would perish. 
 
 What the internal or central part of the 
 earth is composed of is utterly unknown 
 to us, though many opinions have been 
 formed respecting it ; the utmost depth to 
 which it hath been penetrated by human 
 art not being more than 2400 feet, or less 
 than half a mile, which, when compared 
 with the length of the diameter, is a very 
 -short distance indeed.. From its mean 
 density, however, which is to that of wa- 
 ter as 9 to 2, and to common stone as 9 
 to 5, it is presumed that it contains great 
 quantities of metals. 
 
 The figure of the earth is that of a 
 spheroid, having its equatorial diameter 
 longer than its polar diameter. It is con- 
 sequently flattest at the poles, and more 
 protuberant at the equator. 
 
 With respect to the magnitude of the 
 C2 
 
34 The Universe. 
 
 earth, this has been variously determined 
 by different authors, both ancient and 
 modern. The following dimensions may 
 be taken as near the truth. 
 
 The circumference . . 25,OOO miles. 
 The polar diameter . . 7893 miles, 
 The equatorial diameter 7928 miles, 
 The superficies 198,944,206 sq. miles. 
 The solidity 263,930,000,000 cubic m. 
 Also the seas, and unknown parts of the 
 earth, by a measurement of the best maps, 
 contain 160,522,026 square miles ; the in- 
 habited parts, 38,922,180 ; of which Eu- 
 rope contains 4,456,065 ; Asia, 10,768,- 
 823 ; Africa, 9,654,807 ; and America, 
 14,110,874 square miles. 
 
 Of the divisions of the Earth. In tak- 
 ing a view of the terraqueous globe the 
 3iiost obvious divisions that present them- 
 selves, are those that are sketched by the 
 yielding water on the crooked shore, call- 
 ed continents, islands, seas, &c. 
 
 A continent is a large tract of land not 
 separated by the sea ; as Europe, Asia, 
 &c. An ocean is a vast collection of wa- 
 ter not separated by land ; as the Atlan- 
 tic, Pacific, &c. A sea is a smaller col- 
 lection of water communicating with the 
 
The Universe. 35 
 
 ocean ; as the Mediterranean, the Baltic. 
 
 An island is a tract of land surrounded 
 by water; as Great Britain, Ireland, &cc. 
 A lake is water surrounded by land ; as 
 the Lake of Geneva. 
 
 A cape or promontory is a point of land 
 running far into the sea ; as the Cape of 
 Good Hope. A bay is a part of the 
 ocean running far into the land j as the 
 Bay of Biscay. 
 
 A peninsula is land almost surrounded 
 with water ; as the Morea. A gulph is 
 a part of the sea almost surrounded with 
 land ; as the Gulph of Venice. 
 
 An isthmus is the narrow part of land 
 which joins the peninsula to any country ; 
 as the Isthmus of Suez. A Strait is a nar- 
 row passage from one sea to another ; as 
 the Strait of Gibraltar. 
 
 The earth is also divided into four quar- 
 ters ; Europe, Asia, Africa, and America. 
 
 Besides these, there are other divi- 
 sions of a more varying character ; such 
 are the political boundaries that separate 
 kingdoms and empires. 
 
 Kingdoms, provinces, towns, &c. are 
 divisions of the earth that change with th$ 
 
36 The Universe, 
 
 affairs of the nations that have made 
 them ; and accordingly in different ages ? 
 :they alter their appearances. 
 
Solar System* 
 
 CHAP. III. 
 
 Of the Solar System. 
 
 OUR solar system consists of the sun, 
 and the planets, and comets moving about 
 it. 
 
 The planets are bodies which appear 
 to us like stars ; not that they are lumi- 
 nous bodies, that is, have light in them- 
 selves ; but they shine by reflecting the 
 sun. 
 
 They are called planets from a Greek 
 word, which signifies wandering ; be- 
 cause they change their places, and do 
 not always keep the same distance with 
 one another, nor with the fixed stars, as 
 the fixed stars do. 
 
 There are two kinds of planets, prima- 
 ry and secondary. The first move round 
 the sun, and respect him only as the cen- 
 ter of their motions. The secondary 
 planets, called also satellites, or moons, 
 are smaller planets, revolving round the 
 
S3 Solar System. 
 
 primary, while they, with the primary 
 planets about which they move, are car- 
 ried round the sun. The planets move 
 round the sun at various distances, some 
 being much nearer to him than our earth, 
 and others being much further off. 
 
 There are nine primary planets, which 
 are situated with respect to their distan- 
 ces from the sun as follows : 
 
 ? ? <? 
 
 Mercury, Venus, The Earth, Mars, Ceres, Pallas t 
 
 2f " T? $ 
 
 Jupiter, Saturn, and Herschel, or the Georgium Sidus. 
 
 Of these, our earth is accompanied by 
 one moon, Jupiter has four moons, Sa- 
 turn has seven moons, and the Georgium, 
 planet has six moons. None of these 
 moons, except our own, can be seen with- 
 out a good telescope. The other five 
 planets do not appear to have any satel- 
 lites or moons. 
 
 All the planets move round the sun 
 from west to east, and in the same direc- 
 tion do the moons revolve round their 
 primaries, excepting thos^ of the Georgi- 
 um planet, which seem to move in a con- 
 trary direction. The paths in which 
 they move round are called their orbits* 
 
Solar System. * 3$ 
 
 They perform their revolutions also in 
 very different periods of time. The time 
 of performing their revolutions round 
 the sun is called their year, and the time 
 of performing their revolutions on their 
 axes their daij. 
 
 The axis of a planet is an imaginary 
 line conceived to be drawn through its 
 center, about which it revolves as if on a 
 real axis. The extremities of this line t 
 terminating in opposite points of the 
 planet's surface are called its poles. A 
 bowl whirled from one's hand into the 
 open air turns round such a line with- 
 in itself, whilst it moves forward; and 
 such are the lines we mean when we 
 speak of the axes of the heavenly bodies, 
 
 Venus and Mercury being nearer to 
 the sun than our earth, are called inferior 
 planets, and all the rest, which are with- 
 out the earth's orbit, are called superior 
 planets. 
 
 The sun is placed near the common 
 center, or rather in the lower* focus of 
 
 * If a thread be tied loosely round two pins 
 stuck in a table, and moderately stretched by the 
 point of a black-lead pencil carried round by an 
 even motion and light pressure of the hand, an 
 
40 Solar System* 
 
 the orbits of all the planets and comets, 
 and turns round his axis in 25 days 6 
 hours, as is evident by the motion of 
 spots seen on his surface. By the vari- 
 ous attractions of the circumvolving plan- 
 ets, he is agitated by a small motion 
 round the center of gravity of the system. 
 Let us suppose the earth's orbit to be 
 a thin, even, solid plane ; cutting the sun 
 through the center, and extended out as 
 far as the starry heavens, where it will 
 mark the great circle called the Ecliptic. 
 This circle we suppose to be divided into 
 12 equal parts, called Signs ; each sign 
 into 30 equal parts, called Degrees ; each 
 degree into 6O equal parts called Minutes ; 
 and every minute into GO equal parts, 
 called Seconds ; so that a second is the 
 60th part of a minute ; a minute the 60th 
 part of a degree ; and a degree the 360th 
 part of a circle, or 30th part of a Sign. 
 The ^lanes of the orbits of all the other 
 
 ova! ellipsis will be described ; the two points 
 where the pins are fixed being 1 called the foci or 
 focuses thereof. The orbits of all the planets are 
 elliptical, and the sun is placed in or near one of 
 the foci of each of them ; and that in which he is 
 placed is called the lower focus. 
 
Solar System* 41 
 
 planets likewise cut the sun in halves ; 
 but extended to the heavens, form circles 
 different from one another, and from the 
 ecliptic ; one half of each being on the 
 north side, and the other on the south 
 side of it. Consequently the orbit of 
 each planet crosses the ecliptic in two op- 
 posite points, which are called the plan- 
 et's Nodes. 
 
 Mercury is the first planet in the or- 
 der of the system. It is computed to be 
 about 37,000,000 miles distant from the 
 sun, and to move at the rate of 105,000 
 miles an hour, completing its orbit in 
 about 88 of our days, or little less than 
 three months, which is the length of its 
 year. It is not much larger than the 
 moon, being about 3200 miles in diame- 
 ter. 
 
 Venus is the second planet from the 
 sun, remarkable for its brightness, it is 
 computed to be 68,000,000 miles from 
 it, and to move round it at the rate of 
 76,000 miles an hour, completing its 
 annual revolution in 224 days 17 hours, 
 or above 7 months. Its diameter is 
 7700 miles, and its diurnal revolution is 
 performed in 23 hours 22 minutes. 
 D 
 
42 Solar System. 
 
 When it is to the west of the sun, it is 
 a morning star ; when to the east, it is an 
 evening star. 
 
 Our Earth is the third planet in the 
 order of our system. Its diameter is 
 7970 miles, and it turns round on its axis 
 in the course of a day. Its distance from 
 the sun is 95,000,000 miles, and moves 
 at the rate of 58,000 miles an hour, com- 
 pleting its orbit in the course of a year. 
 
 Mars is the fourth planet from the 
 sun, from which it is distant about 
 144,000,000 miles. It moves at the rate 
 of 55,000 miles an hour, and completes 
 its orbit in a little less than two of our 
 years. Its diameter is 4200 miles, and 
 its rotation on its axis is performed in 
 about 24 hours and 39 minutes. 
 
 Ceres Ferdinandea is the fifth planet 
 from the sun. Its diameter is 16O 
 miles, and its distance from the sun is 
 260,000,000 miles. It was discovered 
 on the first day of the present century by 
 Mr. Piazzi, an Italian astronomer. 
 
 Pallas is the sixth planet in the order 
 of the system. It was discovered by 
 Dr. Gibers of Bremen, on the 28ch of 
 March, 1802. Its distance from the sun 
 
Solar System* 43 
 
 is 266,000,000 miles, and its diameter 
 80 miles. 
 
 This planet and the last Dr. Herschel 
 proposes to call asteroids, because they 
 are so much smaller than any of the oth- 
 er planets. 
 
 Jupiter is the seventh planet in the or- 
 der of our system, and the largest that 
 has yet been discovered, being nearly a 
 thousand times as large as our earth. 
 He is computed to be about 490,000,000 
 miles from the sun, to go at the rate of 
 29,000 miles an hour, and to be 89,000 
 miles in diameter. He finishes his annu- 
 al period in eleven of our years 314 days 
 and 12 hours, and turns round his axis 
 in 9 hours 56 minutes ; so that his year 
 contains 10,470 days* From this plan- 
 et's turning so swiftly on its axis, its fi- 
 gure is more oblate than that of the earth, 
 being more than six thousand miles long- 
 er in its equatorial than in its polar di- 
 ameter ; this swiftness of its diurnal mo- 
 tion also draws its clouds and vapours 
 into streaks or lines over its equatorial 
 parts, forming what is called Jupiter's 
 belts. 
 
 Saturn is the eighth planet from the 
 
44 Solar System. 
 
 sun, and is about 900,000,000 miles dis- 
 tant from it ; it is carried along its orbit 
 at the rate of 22,000 miles an hour, which 
 it completes in 29 l of our years. Its 
 diameter is computed to be 79,OOO miles ; 
 its rotation on its axis has been discover- 
 ed by Herschel to be completed in about 
 ten hours and a quarter. There is a ring, 
 or a broad circular arch, encompasses 
 the body of this planet, without touching 
 it, somewhat similar to the wooden hori- 
 zon of an artificial globe ; only that the 
 interior space occupied by the planet is 
 very considerable. It is about 21,000 
 miles in breadth ; which is equal to its 
 distance from Saturn on all sides. It 
 appears like a large luminous arch in the 
 heavens, as if it did not belong to the 
 planet. 
 
 Herschel is the ninth planet in the or- 
 der of our system, and is twice as far dis- 
 tant as Saturn from the sun, and will be 
 nearly 83 years in going round it. It 
 is ninety times as large as the earth, and 
 is visible to the naked eye on a clear eve- 
 ning, if the moon be absent. 
 
 Thtrse with their moons we consider 
 as the regular bodies of our system, so 
 
Solar System* 45 
 
 regular indeed, that their phenomena 
 may be pretty exactly calculated for ages. 
 There may be other planets, which hu- 
 man observation has not yet discovered, 
 and which, perhaps, it never may. 
 
 All the planets move nearly in the di- 
 rection of the ecliptic ; and that space 
 on each side of it, which bounds their ut- 
 most deviations, is called the Zodiac. It 
 is a broad circle or belt in the starry 
 heavens ; and is about 16 degrees in 
 breadth, and the ecliptic equally divides 
 it in two all round, so that the planets are 
 always found amongst some of the con- 
 tellations, which form the twelve signs of 
 the zodiac. 
 
 The reason of their motions in curve 
 lines, is the attraction of the sun, or their 
 gravitations towards the sun (call it 
 which you please ;) and an oblique or 
 side-long impulse or motion ; the former 
 is commonly called the centripetal force , 
 and the latter the centrifugal force. 
 
 These two motions or tendencies, the 
 
 one always endeavouring to carry them 
 
 ma straight line from the circle they move 
 
 in, and the other endeavouring to draw 
 
 D2 
 
46 Solar System. 
 
 them in a straight line to the sun, make 
 that a curve line they revolve in. 
 
 From the great analogy there is be- 
 tween the other planets and our earth it is 
 generally supposed by astronomers that 
 they are inhabited, and indeed we can 
 never bring ourselves to think, that an in- 
 finitely wise Creator should dispose of 
 all his animals and vegetables here, leav- 
 ing the other magnificent planets, with all 
 their noble attendance of moons, bare 
 and destitute of rational creatures. To 
 suppose that he had any view to our bene- 
 fit, in creating these moons, and giving 
 them their motions round Jupiter, Sa- 
 turn arid Herschel; to imagine that he 
 intended these vast bodies for any ad- 
 vantage to us, when he well knew that 
 they could never be seen but by a few 
 astronomers peeping through telescopes : 
 and that he gave to the planets regular 
 returns of days and nights, and different 
 seasons to all where they would be con- 
 venient ; but of no manner of service to 
 us, except only what immediately regards 
 our own planet the earth ; to imagine that 
 he did all this on our account, would be 
 charging him impiously with having 
 
Solar System. 47 
 
 done much in vain ; and as absurd, as to 
 imagine that he has created a little sun 
 and a planetary system within the shell 
 of our earth, and intended them for our 
 use. These considerations amount to 
 little less than a positive proof, that all 
 the planets are inhabited ; for if they are 
 not, why all this care in furnishing them 
 with so many moons, to supply those 
 with light which are at the greater dis- 
 tances from the sun ? Do we not see, 
 that the farther a planet is from the sun, 
 the greater apparatus it has for that pur- 
 pose ? save only Mars, which being but 
 a small planet, may have moons too small 
 to be seen by us. We know that the 
 earth goes round the sun, and turns 
 round its own axis, to produce the vicis- 
 situdes of summer and winter by the 
 former, and of day and night by the latter 
 motion, for the benefit of its inhabitants. 
 IVIay we not then fairly conclude, by pa- 
 rity of reason, that the end and design of 
 all the other planets is the same ? and is 
 not this agreeable to the beautiful harmo- 
 ny which exists throughout th^ universe? 
 Surely it is ; and raises in us the most 
 magnificent ideas of the Supreme Being, 
 
48 Solar System. 
 
 who is everywhere, and at all times pre- 
 sent ; displaying his power, wisdom and 
 goodness among all his creatures ! and 
 distributing happiness to innumerable 
 ranks of various beings ! 
 
 Of Comets. Of all the celestial bodies, 
 comets have given rise to the greatest 
 number of speculations and conjectures. 
 Their strange appearance has in all ages 
 been a matter of terror to the uninform- 
 ed, who have generally looked upon them 
 to be evil omens, and forerunners of war, 
 pestilence, &c. 
 
 The existence of an universal connec- 
 tion between all parts of the siderial hea- 
 vens is now generally admitted. Comets 
 undoubtedly form a part of this great 
 chain ; but of the part they occupy, and 
 of the uses for which they exist, we are 
 in a great measure ignorant. It is a por- 
 tion of science whose perfection is reser- 
 ved for some distant day, when these bo- 
 dies, and their vast orbits, may, by long 
 and accurate observation, be added to the 
 known parts of the solar system ; when 
 astronomy will appear with new lights, 
 after all our discoveries, great as we at 
 
Solar System. 49 
 
 present imagine them to be. Upon the 
 whole, the astronomy of comets is very 
 imperfect ; for but little can be known 
 with certainty where but little can be 
 seen. Comets afford few observations, 
 on which to ground conjecture, and are 
 for the greatest part of their course be- 
 yond the reach of human vision. 
 
 Like the planets, they are observed to 
 be opaque bodies, shining only by the in- 
 fluence of the sun, and like them are car- 
 ried along in their orbits, by the combi- 
 nation of the centripetal and centrifugal 
 forces ; sometimes seeming to go for- 
 wards, sometimes backwards, and some 
 times to be stationary. The great eccen- 
 tricity of their orbits make them liable to 
 suffer considerable alterations, from the 
 attraction of the planets, and of each oth- 
 er. 
 
 They are called comets, from their 
 having a long tail, somewhat resembling 
 the appearance of hair. This, however, 
 is not always the case ; for some comets 
 have appeared, which were as well defi- 
 ned, and as round as planets ; but in gen- 
 eral, they have luminous matter diffused 
 around them, or projecting out from 
 them. 
 
50 Solar System. 
 
 From the beginning of our era to this 
 time, it is probable, according to the best 
 accounts, that there have appeared about 
 500 comets. Before that time about 10O 
 others are recorded to have been seen, 
 but it is probable, that not above half of 
 them were comets. And, when we con- 
 sider, that many others may not have 
 been perceived, from being too near the 
 sun, from appearing in moonlight, from 
 being in the other hemisphere, from be- 
 ing too small to be perceived, or which 
 may not have been recorded, we might 
 imagine the whole number to be consid- 
 erablv greater : but it is likely, that of the 
 comets which are recorded to have been 
 seen, the same may have appeared seve- 
 ral times, and therefore the number may 
 be less than is here stated. 
 
 Of the Moon. The moon goes round 
 the earth from change to change in 29 
 days 12 hours and 44 minutes ; and round 
 the sun with it every year. The moon's 
 diameter is 2180 miles; and her dis- 
 tance from the earth's center 24O,OOO 
 miles. She goes round her orbit in 27 
 days 7 hours 43 minutes, moving about 
 
Solar System. 51 
 
 r2290 miles every hour ; and turns round 
 her axis exactly in the time that she goes 
 round the earth, which is the reason of 
 her keeping always the same side towards 
 us, and that her day and night taken to- 
 gether is as long as our lunar month. 
 
 The moon is an opaque globe like the 
 earth, and shines only by reflecting the 
 light of the Sun ; therefore whilst that 
 half of her which is towards the sun is 
 enlightened, the other half must be dark 
 and invisible. Hence she is incessantly 
 varying her appearance ; sometimes she 
 looks full upon us, and her visage is all 
 lustre ; sometimes she shews only half 
 her enlightened face, soon she appears as 
 a radiant crescent, in a little time all her 
 brightness vanishes, and she becomes a 
 beamless orb. The full moon, or oppo- 
 sition, is that state in which her whole 
 disk is enlightened, and we see it all 
 bright, and of a circular figure. The 
 new moon is when she is in conjunction 
 with the sun ; in this state, the whole 
 surface turned towards us is dark, and is 
 therefore invisible to us. The first quar- 
 ter of the moon she appears in the form 
 of a semicircle, whose circumference is 
 
52 . Solar System. 
 
 turned towards the west. At the last 
 quarter she appears again under the form 
 of a semicircle, but with the circumfer- 
 ence turned towards the east. These 
 phases may be illustrated in a very plea- 
 sing manner, by exposing an ivory ball 
 to the sun, in a variety of positions, by 
 which it may present a greater or small- 
 *er part of its illuminated surface to the 
 observer. If it be held nearly in opposi- 
 tion, so that the eye of the observer be 
 almost immediately between it and the 
 sun, the greatest part of th^; enlightened 
 side will be seen ; but if it be moved in a 
 circular orbit, towards the sun, the visi- 
 ble enlightened pari will gradually de- 
 crease, and at last disappear, when the 
 ball is held directly towards the sun. Or 
 to apply the experiment more immedi^ 
 ately to our purpose ; if the ball, at any 
 time when the sun and moon are both 
 visible, be held directly between the eye 
 of the observer and the moon, that part 
 of the ball on which the sun shines, will 
 appear exactly of the same figure as the 
 moon itself. 
 
 The moon has scarce any difference of 
 seasons ; her axis being almost perpenv 
 
Solar System. 53 
 
 dicular to the ecliptic. What is very 
 singular, one half of her has no darkness 
 at all ; the earth constantly affording it a 
 strong light in the sun's absence ; while 
 the other half has a fortnight's darkness 
 and a fortnight's light by turns. 
 
 Our earth is a moon to the moon, wax- 
 ing and waning regularly, but appearing 
 thirteen times as big, and affording her 
 thirteen times as much light, as she does 
 to us. When she changes to us, the earth 
 appears full to her ; and when she is in 
 her first quarter to us, the earth is in its 
 third quarter to her ; and v ice versa. 
 
 Of Eclipses. When any of the hea- 
 venly bodies is obscured or darkened by 
 the shadow of another falling upon it, or 
 by the interposition of any body, it is said 
 to be eclipsed. 
 
 An eclipse of the moon is, when the 
 earth, being between the sun and the 
 moon, hinders the light of the sun from 
 falling upon and being reflected by the 
 moon. If the light of the sun is kept off 
 from the whole body of the moon, it is a 
 total eclipse j if from a part only, it is a 
 partial one. 
 
 E 
 
y4t Solar System. 
 
 An eclipse of the swi is, when the 
 moon, being between the sun and the 
 earth, hinders the light of the sun from 
 coming to us. If the moon hides from, 
 us the whole body of the sun, it is a to- 
 tal eclipse, if not, a partial one. 
 
 The eclipses of the sun and the moon, 
 though expressed by the same word, are 
 in nature very different ; the sun, in re- 
 ality, loses nothing of its native lustre in 
 the greatest eclipses, but is all the while 
 incessantly sending forth streams of light 
 every way around him, as copiously as 
 before. Some of these streams are, how- 
 ever, intercepted, in their way towards 
 our earth, by the moon coming between 
 the earth and the sun ; and the moon ha- 
 ving no light of her own, and receiving 
 none from the sun on that half of the 
 globe which is towards our eye, must 
 appear dark, and make so much of the 
 sun's disk appear so, as is hid from us by 
 her interposition. What is called an 
 eclipse of the sun, is therefore, in reality, 
 an eclipse of the earth, which is deprived 
 of the sun's light, by the moon's coming 
 between, and casting a shadow upon it. 
 The earth being a globe, only that half 
 
Solar System. 55' 
 
 F it, which at any time is turned towards 
 the sun, can be enlightened by him at 
 that time : it is some part of this enlight- 
 ened half of the earth that the moon's 
 shadow falls on in a solar eclipse. 
 
 In any year the number of eclipses of 
 both luminaries cannot be less than two,, 
 nor more than six* Eclipses of the sun 
 are more frequent than of the moon, be- 
 cause the sun's ecliptic limits are greater 
 than the moon's ; yet we have more visi- 
 ble eclipses of the moon than of the sun, 
 because eclipses of the moon are seen 
 from all parts of that hemisphere of the 
 earth which isnext them, and are equally 
 great to each of those parts ; but the sun's 
 eclipses are visible only to that small 
 portion of the hemisphere where the 
 moon's shadow falls. 
 
 An eclipse of the moon can never hap- 
 pen but at the time of full moon. 
 
 An eclipse of the sun always begins on 
 the western, and ends on the eastern side ; 
 because the moon, moving in her orbit 
 from west to east, necessarily first ar- 
 rives and touches the sun's western limb, 
 and goes off at the eastern ; that of the 
 
5"6 Solar System. 
 
 moon commences at the eastern and ends 
 at the western. 
 
 The Satellites, or moons, are often 
 eclipsed by the planets to which they be- 
 long. 
 
 A digit is the 12th part of the sun or 
 moon's diameter, and is a term often 
 used in speaking of eclipses. The disk 
 of the sun or moon is its round face, 
 which, on account of the great distance 
 of the object, appears fiat. The edge or 
 border of the disk is called the limb. 
 
 The immersion of a heavenly body, is 
 the time when an eclipse begins ; its 
 -emersion is when it begins to re-appear. 
 
Fixed Stars. 57 
 
 CHAP. IV. 
 Of the Fixed Stars, 
 
 NO part of the universe affords such 
 exalted ideas of the structure and mag- 
 nificence of the heavens, as the consider- 
 ation of the number, magnitude, nature, 
 and distance of the fixed stars. We ad- 
 mire indeed, with propriety, the vast 
 bulk of our own globe ; but, when we 
 consider how much it is surpassed by 
 most of the heavenly bodies, what a point 
 it degenerates into, and how little more 
 even the vast orbit in which it revolves 
 would appear, when seen from some of 
 the fixed stars, we begin to conceive more 
 just ideas of the extent, of the universe, 
 and of the infinity of creation. 
 
 The fixed stars comprehend all the ce- 
 lestial objects, excepting the sun, the 
 moon, and the planets, and some comets 
 which now and then appear, 
 E2 
 
58 fixed Star, s. 
 
 The stars, on account of their apparent- 
 ly various magnitudes,have been distribu- 
 ted into several classes or orders. Those 
 which appear largest, are called stars of 
 the first magnitude ; the next to them in 
 lustre, stars of the second magnitude; and 
 soon to the sixth, which are the smallest 
 that are visible to the bare eye. This 
 distribution having been made long be- 
 fore the invention of telescopes, the stars 
 which cannot be seen without the assist- 
 ance of these instruments, are distinguish- 
 ed by the name of telescopic stars. 
 
 They are likewise distinguished, with 
 regard to their situation, into asterisms, 
 or constellations ; which are nothing but 
 assemblages of several neighbouring stars 
 considered as constituting some deter- 
 minate figure, as of an animal, &c. from 
 which it is therefore denominated. 
 
 The number of constellations in the 
 northern hemisphere is 35 ; in the south- 
 ern 32 ; and in the ecliptic 12. Those 
 stars which are not : in the con- 
 
 stellations, are called unformed stars ; 
 those clusters of stars which are so dis- 
 tant as not to be distinctly seen, are, from 
 their cloudy appearance, comprised ua- 
 
Fixed Stars. 59 
 
 der the name of nebulce ; and that light- 
 coloured irregular circle or band which 
 encompasses the heavens, and is distin- 
 guishable from the etherial blue by its 
 brilliancy ; that shining zone, which 
 owes its splendour to the innumerable 
 stars of which it is formed, and which 
 passes through many of the constellations 
 in its ample range, is called the Galaxy^ 
 the via lactea, or the milky way. 
 
 The idea of classing the stars under 
 well known forms probably originated 
 with the Egyptian shepherds, who dur- 
 ing the silent watches of the night (as 
 they slept in the open air) had no other 
 objects to contemplate than those which 
 the starry heavens presented ; among 
 these, assisted by the powers of a fertile 
 imagination, they discovered a distant 
 resemblance of such things as they were 
 most familiar with. The shepherds thus 
 conceiving the figures of things in the 
 firmament, the poets embellished the il- 
 lusion with the fictions of mythology, 
 till the heavens were, as it were, filled 
 with these imaginary creatures, and these 
 were increased in after ages, and served 
 astronomers in their accounts of the star- 
 
60 Fixed Stars. 
 
 ry heavens, as the present divisions of 
 the earth help geographers in the descrip- 
 tion of the globe. 
 
 The twelve constellations which sur- 
 round the ecliptic, commonly called the 
 twelve signs of the zodiac, are the fol- 
 lowing Aries the Ram, Taurus the Bull, 
 Gemini the Twins, Cancer the Crab, Leo 
 the Lion, Virgo the Virgin, Libra the 
 Balance, Scorpio the Scorpion, Sagittar- 
 rius the Archer, Capricornus the Goat, 
 Aquarius the Water-bearer, and Pisces 
 the Fishes ; and they are noted on globes, 
 &c. in the following manner : 
 Aries. Taurus. Gemini, Cancer. Leo. Virgo. Libra. 
 
 T 8 n SI ?>% =*= 
 
 Scorpio. Saggitturrius. Capricornus. Aquarius. Pisrts. 
 Til $ V? X 
 
 The former six are called northern, and 
 the latter southern signs ; because the 
 former possess that half of the ecliptic 
 which lies to the northward of the equi- 
 noctial ; and the latter that which lies to 
 the southward. The northern are our 
 summer signs, the southern our winter 
 ones. 
 
 As these twelve signs answer to the 
 twelve months in the year, it is a very 
 
Fixed Stars. 61 
 
 probable conjecture that the figures un- 
 der which they are represented are de- 
 scriptive of the seasons of the year, 01* 
 months, in the sun's path ; thus, the first 
 sign Aries, denotes, that, about the time 
 when the sun enters that part of the 
 ecliptic, the lambs begin to follow the 
 sheep ; that on the Sun's approach to the 
 second constellation, Taurus the Bull, is 
 about the time of the cows bringing forth 
 their young. The third sign, now Ge- 
 mini, was originally two kids, and signi- 
 fied the time of the goats bringing forth 
 their young, which are usually two at a 
 birth, while the former, the sheep and 
 cow, commonly produce only one. The 
 fourth sign, Cancer, the Crab, an animal 
 that goes side-ways and backwards, was 
 placed at the northern solstice, the point 
 where the sun begins to return back again 
 from the north to the southward. The 
 fifth sign, Leo, the Lion, as being a very 
 furious animal, was thought to denote the 
 heat and fury of the burning sun, \vhen 
 he has left Cancer, and entered the next 
 sign Leo. The succeeding constellation, 
 the sixth in order, received the sun at the 
 time of ripening corn and approaching 
 
62 Fixed Stars. 
 
 harvest ; which was aptly expressed by 
 one of the female reapers, with an ear of 
 corn in her hand, viz. Virgo, the Maid. 
 The ancients gave to the next sign, Scor- 
 pio, two of the twelve divisions of the 
 zodiac ; autumn, which affords fruits in 
 great abundance, affords the means and 
 causes of diseases, and the succeeding 
 time is the most unhealthy of the year ; 
 expressed by this venomous animal, here 
 spreading out its long claws into one sign, 
 as threatening mischief, and in the other 
 brandishing his tail to denote the comple- 
 tion of it. The fall of the leaf was the 
 season of the ancient hunting ; for which 
 reason the stars which marked the sun's 
 place at this season, into the constellation 
 Sagittary, a huntsman with his arrows 
 and his club, the weapon of destruction 
 for the large creatures he pursued. The 
 reason of the Wild Goat's being chosen to 
 mark the southern solstice, when the suti 
 has attained his extreme limit that way, 
 and begins to return and mount again to 
 the northward, is obvious enough ; the 
 character of that animal being that it is 
 mostly climbing, and ascending some 
 mountain, as it browses. There yet re- 
 
Fixed Stars. 63 
 
 main two of the signs of the zodiac to 
 be considered with regard to their origin, 
 viz. Aquarius and Pisces. As to the 
 former, it is to be considered that the win- 
 ter is a wet and uncomfortable season ; 
 this therefore was expressed by Aquari- 
 us, the figure of a man pouring out water 
 from an urn. The last of the zodiacal 
 constellations was Pisces, a couple of 
 fishes tied together, that had been caught; 
 the lesson was, The severe season is 
 over ; your flocks do not yet yield then- 
 store, but the seas and rivers are open, 
 and there you may take fish in abun- 
 dance. 
 
 With respect to the distances of the 
 fixed stars, they are so extremely remote, 
 that we have no distances in the planeta- 
 ry system to compare to them. 
 
 The distance of the star Draconis (a 
 star of the fifth magnitude) appears, by 
 Dr. Bradley's observations, to be at least 
 400,000 times that of the sun, and the 
 distance of the nearest fixed star not less 
 than 40,000 diameters of the earth's an- 
 nual orbit ; that is, the distance from the 
 earth, of the former at least 38,000,000,- 
 000,000 miles, and the latter not less than 
 
64- Fixed Stars. 
 
 7,600,000,000,000 miles. As these dis- 
 tances are immensely great, it may both 
 be amusing, and help to a clearer and 
 more familiar idea, to compare them with 
 the velocity of some moving body, bj 
 which they may be measured. 
 
 The swiftest motion we know of, is 
 that of light, which passes from the sun 
 to the earth in about eight minutes ; and 
 yet this would be above six years travers- 
 ing the first space, and near a year and a 
 quarter in passing from the nearest fixed 
 star to the earth. But a cannon-ball, 
 moving on a medium at the rate of about 
 twenty miles in a minute, would be 
 3,800,000 years in passing from Draco- 
 nis to the earth, and 760,000 years pass- 
 ing from the nearest fixed star. Sound, 
 which moves at the rate of about thir- 
 teen miles in a min. would be 5,60O,OOO 
 years traversing the former distance, and 
 1,128,000 in passing through the latter. 
 The celebrated Kuygens pursued specu- 
 lations of this kind so far, as to believe 
 it not impossible, that there may be stars 
 at such inconceivable distances, that their 
 light has not yet reached the earth sincp 
 the creation. 
 
Fixed Stars. 65 
 
 Though the number of the stars ap- 
 pears to be immensely great ; yet have 
 astronomers long since ascertained the 
 number of such as are visible to the 
 eye, which are much fewer thaii at first 
 sight could be imagined. Of the 3000 
 contained in Flamstead's catalogue, there 
 are many that are only visible through a 
 telescope ; and a good eye scarcely ever 
 sees more than a thousand at the same 
 time in the clearest heaven ; the appear- 
 ance of innumerable more, that are fre- 
 quent in clear winter nighty, arising from 
 our sight's being deceived by their twink- 
 ling, and from our viewing them confu- 
 sedly, and not reducing them to any or- 
 der. But a good telescope, directed in- 
 differently to almost any point of the hea- 
 vens, discovers multitudes that are lost to 
 the naked eye ; particularly in the milky 
 way. And F. de Rheita affirms, that 
 he has observed above 2000 stars in the 
 single constellation of Orion. The same 
 author found above 188 in the Pleiades. 
 Galileo found eighty in the space of the 
 belt of Orion's sword, twenty-one in the 
 nebulous star of his head, and above 50O 
 in another part of him, within the com- 
 F 
 
66 Fixed Stars. 
 
 pass of one or two degrees of space, and 
 more than forty in the nebulous star 
 Prsesepe, and the recent disco\ 7 eries of 
 Dr. Herschel have proved the fixed stars 
 to be immense, their regions unbounded, 
 and perhaps infinite ! 
 
 As the stars, contrary to the moon and 
 planets, shine like our sun, by their own 
 native light, astronomers suppose that 
 each of them is a sun, with its system of 
 inhabited worlds revolving round it. Un- 
 der this idea or persuasion, of how innu- 
 merable a family do we seem to make a 
 part ! The immensity of the universe be- 
 comes peopled with fellow beings, and 
 we feel an interest in what appears to be 
 going on at distances so vast, that what 
 we see, as in time present, we have rea- 
 son to believe (swift, as is the progress of 
 light, darting from the spheres) must 
 have happ;n<, J many ages ago. Under 
 the idea of the universe being replenish- 
 ed with human brings, how magnificent, 
 how awful, are tne spectacles that present 
 themselves to the observer of the hea- 
 vens ! The creature of a day, of a few 
 fleeting moments, seems to obtain a 
 glimpse of a nqw creation, a glimpse of 
 
Fixed Stars. 67 
 
 the end of time, in the passing away of a 
 system. 
 
 What an amazing conception, if hu- 
 man imagination can conceive it, does 
 this give of the works of the Creator! 
 Thousands of thousands of suns, multi- 
 plied without end, and ranged ail around 
 us, at immense distances from each oth- 
 er, attended by ten thousand times ten 
 thousand worlds, all hung loosens it were, 
 in boundless space, upheld by nothing, 
 confined by nothing, yet preserved in 
 their rapid course, calm, regular and har- 
 monious, invariably keeping the paths 
 assigned them by the sovereign Artificer. 
 
68 The Earth considered as a Planet. 
 
 CHAP. V. 
 
 Of the Earth considered as a Planet, 
 
 THE Earth goes round the sun in 365 
 days 5 hours 49 minutes, from an equi- 
 nox or solstice to the same again ; but 
 from any fixed star to the same again, 
 as seen from the sun, in 365 days, 6 hours 
 and nine minutes ; the former being the 
 length of the tropical ijear, and the latter 
 the length of the sidereal. 
 
 The motion of the earth in common 
 with the rest of the planets about the 
 sun, is in the order of the signs of the 
 zodiac ; that is, from west to east. This 
 zone or belt, as has been mentioned, goes 
 round the heavens ; and along the middle, 
 of it is the ecliptic, or circle which the 
 earth describes annually as seen from 
 the sun ; and which the sun appears to 
 describe as seen from the earth. 
 
 Besides this annual revolution of the 
 earth about the sun, in the ecliptic ; the 
 
The Earth considered as a Planet. 69 
 
 earth turns round upon its own axis in 
 24 hours. 
 
 The turning of the earth upon its own 
 axis every 24 hours, whilst it moves 
 round the sun in a year, we may conceive 
 by the running of a howl on a bowling 
 green ; in which not only the center of 
 the bowl hath a progressive motion on the 
 green ; but the bowl in its going forward, 
 from one part of the green to another, 
 turns round about its own axis. 
 
 The turning of the earth on its axis, 
 makes the difference of day and night ; it 
 being day in those parts of the earth, 
 which are turned towards the sun ; and 
 night in those parts which are in the 
 shade, or turned from the sun. 
 
 The annual revolution of the earth in 
 the ecliptic, is the cause of the different 
 seasons, and of the several lengths of days 
 and nights, in every part of the world, in 
 the course of the year. 
 
 But before we enter upon the more 
 particular illustration of the diurnal and 
 annual motions of the earth, together 
 with the different lengths of days and 
 nights, and all the beautiful variety of 
 seasons, depending on those motions, it 
 F2 
 
70 The Earth considered as a Planet. 
 
 may be necessary to make the reader ac- 
 quainted with the principle circles of the 
 globe, as they will greatly assist him in 
 comprehending those phenomena. 
 
 This information he may attain suffi- 
 ciently for his present purpose in a quar- 
 ter of an hour, if he sets the ball of a ter- 
 restrial globe before him, or looks at the 
 figure of it, wherein these circles are 
 drawn and named. 
 
 The Poles are the two extremities of 
 the earth's axis ; or those points where 
 the imaginary line, round which it per- 
 forms its daily revolutions, meets the 
 earth's surface ; that which is directed 
 towards the most northern point of the 
 heavens, being called the north pole ; and 
 that which is directed towards tke most 
 southern point, the south pole ; so that 
 they are di am e trie ally opposite to each 
 other, and always preserve the same rela- 
 tive situation. It is also to be observed, 
 that these two points have not been arbi- 
 trarily assumed by geographers and as- 
 tronomers, to answer their particular pur- 
 poses, as they are pointed out to us by 
 the nature and constitution of the globe, 
 and are easily distinguished from all 
 
/ The Earth considered as a Planet. 71 
 
 others. The nearer we approach to them, 
 the more we find the earth becomes bar- 
 ren and inhospitable ; so that, under the 
 poles, the cold is so excessive, that the 
 country must be nearly uninhabitable. 
 Imagine now a circle to be drawn round 
 the globe, exactly in the middle, between 
 these two points, and this will be the 
 Equator ; which, properly speaking, is a 
 great circle of the earth, that separates 
 the northern from the southern hemis- 
 phere, and is every where at an equal dis- 
 tance from the poles. This circle is al- 
 so no less remarkable, on account of its 
 situation, than the poles ; the heat being 
 here almost as intense as the cold is 
 there. Every place is said to have north 
 or south latitude as it is on the northern 
 or southern side of this great circle. 
 
 The Tropics are lesser circles parallel 
 to the equator, and each of them is 23 1 
 degrees from it ; a degree in this sense 
 being the 360th part of any great circle 
 which divides the earth into two equal 
 parts. The northern tropic touches the 
 ecliptic at the beginning of Cancer, and 
 is thence called the Tropic of Cancer ; 
 the southern tropic, touching the ecliptic 
 
72 The Earth considered as a Planet. 
 
 at the beginning of Capricorn, is therefore 
 called the Tropic of Capricorn. 
 
 The Arctic Circle has the north pole for 
 its centre, and is just as far from the north 
 pole as the tropics are from the equator ; 
 and the Antarctic Circle (hid by the sup- 
 posed convexity of the figure) is just as 
 far from the south pole, every way round , 
 it. 
 
 The circles 12. 1. 2. 3. 4. &c. are meri- 
 dians to all places they pass through ; and 
 we must suppose thousands more to be 
 drawn, because every place that is ever 
 so little to the east or west of any other 
 place, has a different meridian from 
 that other place. All the meridians meet 
 in the poles ; and whenever the sun's cen- 
 ter is passing over any meridian, in his 
 apparent motion round the earth, it is 
 mid-day or noon to all places on that me- 
 ridian. The longitude of a place is its 
 distance east or west from the first meri- 
 dian, reckoned in degrees, minutes, &c. 
 upon the equator. Supposing we call 
 London the first, it will cut the equator 
 in two opposite points at the distance of 
 one hundred and eighty degrees each 
 way ; and as the equator is the boundary 
 
The Earth considered as a Planet. 73 
 
 which separates the northern hemisphere 
 from the southern, so this circle may be 
 considered as the boundary which sepa- 
 rates the eastern hemisphere from the 
 western. 
 
 The broad space lying between the 
 tropics, like a girdle surrounding the 
 globe, is called the Torrid Zone, because 
 the sun is at one time or other perpendi- 
 cular over every part of it, and extreme- 
 ly torrifies or heats it. The space be- 
 tween the tropic of Cancer and arctic 
 circle is called the North Temperate Zone; 
 that between the tropic of Capricorn and 
 the antarctic circle, the South Temperate 
 Zone: from their enjoying a mean or 
 moderate degree of heat ; and the two 
 circular spaces bounded by the polar cir- 
 cles are the two Frigid Zones ; so named 
 because of the intense cold which reigns 
 in those regions the greatest part of the 
 year ; and they are denominated north or 
 south, from that pole which is in the cen- 
 ter of the one or the other of them. 
 
 Of the Seasons, s?c. -Nature is always 
 grand in her designs, sublimity and sim- 
 plicity are the striking characteristics of 
 
74 The Earth considered as a Planet. 
 
 her workmanship. From a few simple 
 principles she produces the most aston- 
 ishing effects, and charms us no less by 
 the infinite diversity of her operations, 
 than by the skill and contrivance which 
 are manifested in the performance of 
 them. Of all the effects resulting from 
 her laws none is more simple nor more 
 pleasing to a philosophic mind than the 
 provision that is made for the alternate 
 succession of day and night, and the 
 regular return of the seasons. The phe- 
 nomena depend upon the most simple 
 and evident principle. We have the one 
 merely from the rotation of our globe on 
 its axis, and the other from the inclina- 
 of that axis to the plane of its orbit. 
 
 The axis of the earth being inclined 
 23-| degrees to the plane of its orbit, 
 makes it, in moving round the sun, have 
 sometimes one of its poles and some- 
 times the other nearer that luminary. 
 
 The absence of the sun's light pro- 
 duces a proportionable degree of cold ; 
 hence the seasons are, in the northern 
 and southern parts of the globe, distinctly 
 marked by different degrees of heat and 
 sold. It is this annual turning of the 
 
The Earth considered as a Planet. 75 
 
 poles towards the sun, that occasions the 
 very long days in the northern and south- 
 ern parts. It is owing to the same cause, 
 that the sun seems to rise higher in the 
 heavens during summer than in winter ; 
 and this alternate sinking and rising is 
 perceptible over the whole globe. 
 
 In order to illustrate this subject let 
 us now take a view of the earth in its an- 
 nual course round the sun, considering' 
 its orbit as having no inclination | and 
 its axis as inclining 23 -| degrees from 
 a line perpendicular to the plane of its 
 orbit, and keeping the same oblique di- 
 rection in all parts of its annual course ; 
 or, as commonly termed, keeping always 
 parallel to itself. 
 
 In Fig. 2 let S represent the sun, the 
 four globes the earth in different parts of 
 its orbit, receiving from its changing po- 
 sition the varying seasons. Ns its axis, 
 N its north pole, s its south pole. As it 
 goes round the sun, according to the order 
 of the signs of the zodiac, its axis Ns 
 keeps the same obliquity, and is still par- 
 allel to itself. 
 
 We shall commence its annual round at 
 the first point of Libra, when the sun, as 
 
76 The Earth considered as a Planet. 
 
 seen from the earth will appear to enter 
 Aries. At this time, namely the 20th of 
 March, the sun will be in the equinoctial, 
 and all parts of the earth will be equally 
 enlightened from pole to pole, and the 
 days and nights equal all over the world, 
 for every part comes into the light at six 
 in the morning, and goes into the dark at 
 six in the evening. As the earth passes 
 on in the order of the signs, in about three 
 months, viz. on the 21st of June, it will 
 arrive at the beginning of Capricorn, and 
 the sun, as seen from the earth, will ap- 
 pear at the beginning of Cancer ; during 
 which time, by the inclined position of the 
 earth's axis, the north pole will have gra- 
 dually advanced into the enlightened 
 hemisphere ; so that the whole northern 
 polar circle will be therein, while the 
 southern pole ir> immerged in obscurity ; 
 the northern parts of the world will enjoy 
 long days, while they are short in the 
 southern parts. In this situation of the 
 earth the tropic of Cancer is in the light 
 from five in the morning till seven at night, 
 the parallel of London from a quarter be- 
 fore four till a quarter after eight ; and 
 the polar circle just touches the dark, so 
 
The Earth considered as a Planet. 77 
 
 that the sun has only the lower half of his 
 disk hid from the inhabitants on that cir- 
 cle for a few minutes about midnight. 
 
 After this the days begin to shorten in 
 the northern parts of the world, and the 
 nights lengthen in proportion as the earth 
 advances to the first point of Aries, at 
 which it arrives on the 23d of September, 
 when the sun, as seen from the earth, 
 will appear in .Libra. On this day the 
 sun will be in the equinoctial again, and 
 the days and nights will again be equal 
 all over the globe. As the earth pro- 
 ceeds on its orbit from this point, the 
 north pole gradually goes into the dark ; 
 and the south pole advances into the err- 
 lightened hemisphere ; and on the 22d of 
 December, when the earth enters Cancer, 
 and the sun appears at Capricorn, the 
 north pole will be as far as it can be in the 
 dark, which is 23-| degrees, equal to 
 the inclination of the earth's axis from a 
 perpendicular to its orbit : and then, the 
 northern parts are as much in the dark as 
 they were in the light on the 21st oijime; 
 the winter nights being as long as the 
 summer days, and the winter days as 
 short as the summer nights. 
 G 
 
78 The Earth considered as a Planet. 
 
 Thus we see while the earth is moving 
 from Libra through Capricorn to Aries, 
 the north pole remains in the illuminated 
 hemisphere, and will therefore have six 
 months of continual day. But in the 
 other half year, while the earth is moving 
 from Aries through Cancer to Libra, the 
 north pole is turned from the sun, and 
 therefore in darkness, but the south pole 
 is in the illuminated hemisphere. Hence 
 it is easy to perceive, that the inhabitants 
 of the southern hemisphere have the same 
 vicissitudes with those of the northern, 
 though not at the same time, it being win- 
 ter in one hemisphere when it is summer 
 in the other. 
 
 During this annual course of the earth 
 there are four days in her orbit particu- 
 larly to be remarked ; these astronomers 
 have distinguished by the names of the 
 solstitial and equinoctial days. The sol- 
 stitial days are those on which the sun ap- 
 pears most to the northward and the 
 southward ; they are our longest and 
 shortest days, and are called the -winter 
 and summer solstices. The equinoctial 
 days are those on which the sun appears 
 in the equator, and the days are equal to 
 
The Earth considered as a Planet. 79 
 
 the nights, which is twice in every annual 
 revolution of the earth, and are called the 
 autumnal and vernal equinoxes. 
 
 The earth's annual motion causes an 
 apparent daily declination of the sun, or 
 in other words, he appears at different dis- 
 tances from the equator every diurnal 
 turn of the earth on its axis. Thus, about 
 the 22d of December, when the earth is 
 in Cancer, the sun will be over the tropic 
 of Capricorn ; and consequently, by the 
 earth's rotation on its axis, the inhabitants 
 of every part of this circle will success- 
 ively have the sun in their zenith, or, in 
 other words, he will be vertical to them 
 that day at noon. About the 20th of 
 March the earth is at Libra, and the sun 
 will then appear in Aries ; a central solar 
 ray will terminate upon the surface of the 
 earth in the equator ; and therefore the 
 sun appears to be carried round in the 
 celestial equator, and is successively ver- 
 tical to those who live under that circle. 
 About the 21st of June, when the earth 
 is in Capricorn, a central solar ray ter- 
 minates on the surface of the earth, in 
 the northern tropic, and for that day the 
 sun appears to be carried round in the tro- 
 
80 The Earth considered as a Planet, 
 
 pic of Cancer, and is vertical to those 
 who live under that circle. About the 
 23d of September the earth is in Aries, 
 and the sun in Libra, and the central so- 
 lar ray again terminates at the equator ; 
 consequently the sun again appears in the 
 celestial equator, and is vertical to those 
 who live under it. 
 
 We have seen, that, as the sun appears 
 to move in the ecliptic, from the vernal 
 equinox to the tropic of Cancer, it gets 
 to the north of ths equator, or its decli- 
 ivition towards our pole increases. There- 
 fore, from the vernal equinox, when the 
 days and nights are equal, till the sun 
 comes to the tropic of Cancer, our days 
 lengthen, and our nights shorten ; but, 
 when the sun comes to the tropic of Can- 
 cer, it is then in its utmost northern lim- 
 it, and returns in the ecliptic to the equa- 
 tor again. During this return of the sun, 
 its declination tov/urds our pole decrea^s, 
 and consequently the days decrease, and 
 rights increase, till the sun is ar- 
 rived in die equator 'again, and is in the 
 autumnal equinoctial point, when the 
 (I ivs ts will ngain be equal. As the 
 
 sun moves from thence towards the tro- 
 
The Earth considered as a Planet, 81 
 
 pic of Capricorn, it gets to the south of 
 the equator ; or its declination towards 
 the south pole increases. Therefore, at 
 that time of year, our days shorten, and 
 our nights lengthen, till the sun arrives 
 at the tropic of Capricorn; but, when 
 the sun is arrived there, it is then at its 
 utmost southeren limit, and returns in 
 the ecliptic to the equator again. Dur- 
 ing this return, its distance from our pole 
 lessens, and consequently the days will 
 lengthen, as the nights will shorten, till 
 they become equal, when the sun is come 
 round to the vernal equinoctial point. 
 
 The earth's orbit being elliptical, and 
 the sun constantly keeping in its lower 
 focus, which is 1,377,000 miles from the 
 middle point of the longer axis, the earth 
 comes twice so much, or 2, 754,000 miles 
 nearer the sun at one time of the year 
 than at another: for the sun appearing 
 under a larger angle in our winter than 
 summer, proves that the earth must be 
 nearer the sun in the former season than 
 in the latter. How then does it happen 
 that we have not the hottest weather 
 when we are at the least distance from the 
 sun : The earth is above 2,000,000 of 
 02 
 
82 The Earth considered as a Planet. 
 
 miles nearer to the sun in December than 
 it is in June, and yet in June it is the 
 middle of summer, and in December the 
 depth of winter, which seems a paradox. 
 To obviate this apparent contradiction* 
 it may be observed that the eccentricity 
 of the earth's orbit bears no greater pro- 
 portion to the earth's mean distance from 
 the sun than about 1 to 60, and therefore 
 this small difference of distance cannot 
 occasion any great variation in the heat 
 and cold of the different seasons. But 
 the principal cause of this difference is, 
 that in winter the sun's rays fall so ob- 
 liquely upon us, that any given number 
 of them is spread over a much greater 
 portion of the earth's surface where we 
 live ; and therefore each point must then 
 have fewer rays than in summer.- 
 Moreover, there comes a greater degree 
 of cold in the long winter nights, than 
 there can return of heat in so short days ; 
 1 on both these accounts the cold must 
 increase. But in summer the sun's rays 
 fall more perpendicularly upon us, and 
 therefore com* with greater force, and in 
 greater numbers i>.. the same place ; and 
 by their kr.ig continuance, a much great- 
 
The Earth considered as a Planet. 83 
 
 er degree of heat is imparted by day than 
 can fly off by night, so that the heat, on 
 all these accounts, will continue to in- 
 crease. 
 
 Thus we see by what simple principles 
 the bountiful Author of Nature has pro- 
 vided us with such a pleasing succession 
 of scenes, summer, winter, spring, and 
 autumn, lead us* insensibly through the 
 varied circle of the year ; and are no less 
 pleasing to the mind, than necessary to- 
 wards bringing to maturity the various 
 productions of the earth. Whether the 
 sun flames in the solstice, or pours his 
 mild effulgence from the equator, we 
 equally rejoice in his presence, and adore 
 that omniscient Being who gave him his 
 appointed course, and prescribed the 
 bounds which he cannot pass. 
 
 by the daily motion of the earth 
 the rising sun comes within 18 degrees 
 of the horizon, we perceive a faint light 
 begin to appear, which increases, and the 
 magnificent theatre oi the universe opens 
 gradually to our view being fully risen, 
 he rides in all his brightness through the 
 vault of heaven, and approaches the west- 
 
84 The Earth considered as a Planet. 
 
 era boundary of our sight, when the light 
 begins to decrease, and gradually dimin- 
 ishes till he is 18 degrees below the hori- 
 zon, when dark night commences. This 
 intermediate light is called the crepuscu- 
 lum, or the morning and evening twilight. 
 
 As the sun enlightens only one half of 
 the earth at once as it turns round its 
 axis, he rises to some places at the same 
 moments of absolute time when he sets 
 to others ; and when it is mid-day to 
 some places, it is mid-night to others. 
 
 To every place 15 degrees eastward 
 from any given meridian, it is noon an 
 hour sooner than on that meridian ; be- 
 cause their meridian comes to the sun an 
 hour sooner ; and to all places 15 de- 
 grees westward, it is noon an hour later 
 because their meridian comes an hour 
 later to the sun, and so on : every 15 de- 
 grees of motion causing an hour's differ 
 ence of time. Therefore they who have 
 noon an hour later than we, have their 
 meridian, that is, their longitude, 15 de- 
 grees westward from us : and they who 
 have noon an hour sooner than we, have 
 their meridian 15 degrees eastward from 
 ours ; and so for every hour's difference 
 
The Earth considered as a Planet. 85 
 
 of time 15 degrees difference of longi- 
 tude. Consequently, if the beginning or 
 ending of a lunar eclipse be observed, 
 suppose at London, to be exactly at mid- 
 night, and in some other place at 11 at 
 night, that place is 15 degrees westward 
 from the meridian of London ; if the same 
 eclipse be observed at one in the morn- 
 ing at another place, that place is 15 de- 
 grees eastward from the said meridian. 
 
 Of the Precession of the Equinoxes, &?c. 
 Beside the changes in the length ol the 
 days already described in the different 
 seasons, there is another sort of change, 
 not so obviously noticeable. The day 
 and night together, or, in general, 24 
 hours, form the natural or solar day ; and 
 this period of time also varies in its 
 length. The inequality of the solar day 
 is produced by two causes, either o 
 which singly would yield the effect ; 
 these are the obliquity of the ecliptic, and 
 the earth's unequal motion therein. The 
 earth's motion on its axis being uniform 
 and equal at all times of the year, its days 
 would be equal, if its orbit were a perfect 
 circle, and its axis perpendicular to the 
 
86 The Earth considered as a Planet. 
 
 plane of its orbit ; but the earth's annual 
 motion in an elliptic orbit, causes the sun's 
 apparent motion in the heavens to be un- 
 equal. When the sun's annual motion 
 in the heavens appears slowest, it is noon, 
 or 12 on the sun-dial, before it is the 
 same hour on a true-going clock ; and 
 when quickest, it is 12 by the clock be- 
 fore the sun be over our meridian. 
 
 Although the earth be said to complete 
 an orbit round the sun in the course of a 
 year, it does not return exactly to the 
 place it set out from, neither is its cir- 
 cuit completed exactly in a year. Adopt- 
 ing, therefore, the apparent motion in- 
 stead of the real ; if the sun set out as 
 from any star, or other fixed point in the 
 heavens, at the moment it is departing 
 from the equinoctial, or from either tro- 
 pic, it will come to the same equinox, or 
 tropic again, 20 min. 17- sec. of time, 
 or 50 sec. of a degree, before it completes 
 its circuit round the heavens, so as to ar- 
 rive at the same fixed star or point from 
 whence it sets out ; for the equinoctial 
 points recede 50 seconds of a degree west- 
 ward every year, contrary to the sun's 
 annual progressive motion. This is call- 
 ed the Precession of the Equinoxes, 
 
The Earth considered as a Planet. 87 
 
 When the sun arrives at the same equi- 
 noctial or solstitial point, he finishes what 
 we call the tropical year ; which, by ob- 
 servation, is found to contain 365 days 
 5 hours 48 minutes 57 seconds: and 
 when he arrives at the same fixed star 
 again, as seen from the earth, he completes 
 the sidereal year, which contains 365 
 days 6 hours 9 minutes 14~ seconds. 
 The sidereal year is therefore 2O min- 
 utes 17- seconds longer than the solar 
 or tropical year, and 9 minutes 14 1 
 seconds longer than the Julian or civil 
 year, which we state at 365 days 6 hours : 
 so that the civil year is almost a meanbe- 
 twixt the sidereal and tropical. 
 
 The anticipation of the equinoxes, and 
 consequently of the seasons, is by no 
 means owing to the precession of the 
 equinoctial and solstitial points in the 
 heavens (which can only affect the appa- 
 rent motions, places and declinations of 
 the fixed stars) but to the difference be- 
 tween the civil and solar year, which is 
 1 1 minutes 3 seconds ; the civil year con- 
 taining 365 days 6 hours, and the solar 
 year 365 days 5 hours 48 minutes 57 
 seconds, 
 
88 The Earth considered as a Planet. 
 
 The above 11 minutes 3 seconds, by 
 which the civil or Julian year exceeds 
 the solar, amounts to 11 days in 1433 
 years, and so much our seasons have fall- 
 en back with respect to the days of the 
 months, since the time of the Nicene 
 Council in A. D. 325, and therefore in 
 order to bring back all the fasts and fes- 
 tivals to the days then settled, it was re- 
 quisite to suppress 1 1 nominal days. And 
 that the same seasons might be kept to 
 the same times of the year for the future, 
 to leave out the bissextile-day in February 
 at the end of every century of years not di- 
 visible by 4 ; reckoning them only com- 
 mon years, as the 17th, 18th, and 19th 
 centuries, viz. the years 1700, 1800, 1900, 
 cc. because a day intercalated every 
 fourth year was too much, and retail, 
 the bissextile-day at the end of those cen- 
 turies of years which are divisible by 4, as 
 the 16th, 20th, and 24th centuries ; viz. 
 the years 1600, 2000, 2400, &c. Other- 
 wise, in length of time, the seasons would 
 be quite ^reversed with regard to thr 
 months of the year ; though it would 
 have required near 23,783 years to have 
 brought about such a totaj change. 
 
The Earth considered as a Planet, 89 
 
 This new form of reckoning was or- 
 dained by Pope Gregory, and is there- 
 fore called the Gregorian, or the new 
 style, and has been adopted by almost all 
 the enlightened nations of the world ; 
 there are some, however, who still reckon 
 according to the old style, viz. as if no 
 alteration had been made by Pope Gre- 
 gory. 
 
 H 
 
9'0 Atmosphere, 
 
 CHAP. VI. 
 
 Of the Air and Atmosphere. 
 
 WE have already considered the earth 
 as a planet, or one of the great masses 
 of matter moving about the sun ; we shall 
 now consider it as it is made up of its 
 several parts, abstracting from its diur- 
 nal and annual motions. 
 
 The exterior part of this our habitable 
 world is the air or atmosphere ; a light, 
 thin fluid, or springy body, that incom- 
 passes the solid earth on all sides, and 
 partakes of all its motions., both annual 
 and diurnal. 
 
 The composition of that part of our 
 atmosphere properly called air, was till 
 lately but very little known. Formerly 
 it was supposed to be a simple, homoge- 
 neous, and elementary fluid. But the 
 experiments of Dr. Priestley and others 
 have discovered, that even the purest 
 kind of air, which they call vita'. 
 
Atmosphere. 91 
 
 plilogisticated, is in reality a compound, 
 and might be artificially produced in va- 
 rious ways. This dephlogisticated air,> 
 however, is but a small part of the com- 
 position of our atmosphere. By accu- 
 rate experiments, the air we usually 
 breathe, is composed of only one-fourth 
 part of this dephlogisticated air, or per- 
 haps less, the other three parts, or more, 
 consisting of what Dr. Priestly calls phlo~ 
 gisticated, and M. Lavoisier, in the new 
 chemistry, mephitzc, or azotic air, which 
 cannot be breathed, and in which ani- 
 mals die. 
 
 Though air seems to be a kind of re- 
 pository, wherein all the poisonous efflu- 
 via arising from putrid and corrupted mat- 
 ters are lodged ; yet it has a wonderful 
 facilitv of purifying itself, and of deposi- 
 ting those vapours contained in it ; so 
 that it never becomes noxious except in 
 particular places, arid for a short time ; 
 the general mass remaining upon all oc- 
 casions pretty much the same. The way 
 in which this purifaction is effected is dif- 
 ferent, according to the nature of the va- 
 pour with which the air is loaded. That 
 which most universally prevails is water ; 
 
92 Atmosphere. 
 
 and from experiments it appears, that the 
 quantity of aqueous vapour contained 
 in the atmosphere is immense. Dr. 
 Halley, from an experiment on the eva- 
 poration from a fluid surface heated to 
 the same degree with that given by our 
 meridian sun, has calculated, that the 
 evaporation from the Mediterranean Sea 
 in a summer's day is 5280 millions of 
 tons of water, which is more than it re- 
 ceives from all the nine large rivers that 
 empty themselves into it. Dr. Watson, 
 in his Chemical Essays, has given an ac- 
 count of some experiments made with a 
 view to determine the quantity of the wa- 
 ter raised from the "earth itself alone in 
 time of drought. He informs us, that 
 when there had been no rain for above a 
 month, and the grass was become quite 
 brown and parched, the evaporation from 
 an acre was not less than 1600 gallons in 
 twenty-four hours. Making afterwards 
 two experiments, when the ground had 
 been wetted by a thunder-shower the day 
 before, the one gave 1973, the other 1905 
 gallons, in twelve hours. From this the 
 air is every moment purified by the 
 ascent of the vapour, which, flying off in- 
 
Atmosphere. 93 
 
 to the clouds, thus leaves room for the 
 exhalation of fresh quantities ; so that as 
 the vapour is considerably lighter than 
 the common atmosphere, and in conse- 
 quence ascends with great velocity, the 
 air during all this time is said to be dry, 
 notwithstanding the vast quantity of aque- 
 ous fluid that passes through it. 
 
 In the physical economy also, another 
 provision is made for the continual reno- 
 vation of the atmosphere. Plants derive 
 subsistence from the very air that is unfit 
 for animal life, and in return, actually emit 
 that vital or dephlogisticated air, upon the 
 enjoyment of which the latter depends. 
 Thus we see a constant circulation of 
 benefits maintained between the two 
 great provinces of organized nature. The 
 plant purifies what the animal has poison- 
 ed ; in return, the contaminated air is 
 more than ordinarily nutritious to the 
 plant. Agitation with water appears to 
 be another of these restoratives. The 
 foulesi air shaken in a bottle with water 
 for a sufficient length of time, recovers a 
 great degree of its purity. Here, then 
 again, allowing for the scale upon which 
 nature works, we see the salutary effects 
 H2 
 
94 Atmosphere. 
 
 of storms and tempests. The yesty waves, 
 which confound the heaven and the sea, 
 are doing the very thing which is done 
 in the bottle, and are a perpetual scarce 
 of freshness to our atmosphere. 
 
 The atmosphere, as we have seen, 
 contains a great deal of water, together 
 with a vast heterogeneous collection of 
 particles raised from all bodies of matter 
 on the surface of the earth, by effluvia, ex- 
 halations, &c. so that it may be consider- 
 ed as a chaos f the particles of all sorts 
 of matter confusedly mingled together. 
 And hence the atmosphere has been con- 
 sidered as a large chemical vessel, in 
 which the matter of all kinds of subluna- 
 ry bodies is copiously floating ; and thus 
 exposed to the continual action of that 
 immense surface, the sun ; from whence 
 proceed innumerable operations, subli- 
 mations, separations, compositions, di- 
 gestions,fermentations, putrefactions, &c 
 
 There is, however,one substance, nam- 
 ly, the electrical fluid, which is very dis- 
 tinguishable in the mass of the atmos- 
 phere. To measure the absolute quanti- 
 ty of this fluid, either in the atmosphere, 
 or any other substance, is perhaps impos- 
 
Atmosphere. 95 
 
 sible ; and all that we know on this sub- 
 ject is that the electric fluid pervades the 
 atmosphere ; that it appears to be more 
 abundant in the superior than the inferior 
 regions ; that it seems to be the imme- 
 diate bond of connection between the at- 
 mosphere and the water which is suspen- 
 ded in it ; and that, by its various opera- 
 tions, the phenomena of the meteors are 
 occasioned. 
 
 It is the opinion of the most celebrated 
 philosophers of the present day, that the 
 electric fluid is no other than the light of 
 the sun ; that it issues from that lumina- 
 ry in the pure state of electricity, that 
 joining the particles of our atmosphere, it 
 becomes light, and uniting with the gros- 
 ser earth Jire. The evaporation of wa- 
 ter is attended with an absorption of this 
 fluid from the 'surface of our globe, and, 
 on the other hand, the conversion of 
 steam into water, is attended with a de- 
 position of this subtle fluid ; so that there 
 is a circulation in the electric fluid as 
 there is in the water. It descends origin- 
 ally from the sun ; pervades the whole 
 srubstance of the globe ; and perspiring, 
 as it were, at every pore, ascends beyond 
 
96 Atmosphere. 
 
 the clouds ; and, passing the extreme 
 boundaries of our atmosphere, returns to 
 the sun from whence it came. 
 
 The uses of the atmosphere are so ma- 
 ny and great, that it seems indeed abso- 
 lutely necessary, not only to the comfort 
 and convenience of men, but even to the 
 existence of all animal and vegetable life, 
 and to the very constitution of all kinds 
 of matter whatever, and without which 
 they would not be what they are ; for by 
 it we live, breathe, and have our being ; 
 and by insinuating itself into all the va- 
 cuities of bodies, it becomes the great 
 spring of most of the mutations here be- 
 low, as generation,corruption,dissolution, 
 &c. and without which none of these op- 
 erations could be carried on. Without 
 the atmosphere, no animal could exist, 
 or indeed be produced; neither any plant, 
 all vegetation ceasing without its aid ; 
 there would be neither rain nor dews to 
 moisten the face of the ground : and, 
 though we might perceive the sun and 
 stars like bright specks, we should be in 
 utter darkness, having none of what we 
 call day-light, or even twilight: nor would 
 either fire or heat exist without it. In 
 
Atmosphere. 97 
 
 short, the nature and constitution of all 
 matter would be changed and cease; wan- 
 ting this universal bond and constituting 
 principle* 
 
 As to the weight and pressure of the 
 air, it is evident that the mass of the at- 
 mosphere, in common with all other mat- 
 ter, must be endued with weight and 
 pressure ; and this principle was asserted 
 by almost all philosophers, both ancient 
 and modern. But it was only by means 
 of the experiments made with pumps and 
 the barometrical tube, by Galileo and 
 Torricelli, that we came to the proof, not 
 only that the atmosphere is endued with 
 a pressure, but also what the measure 
 and quantity of that pressure is. Thus it 
 is found, that the pressure of the atmos- 
 phere sustains a column of quicksilver, in 
 the tube of the barometer, of about thirty 
 inches in height : it therefore follows, 
 that the whole pressure of the atmosphere 
 is equal to the weight of a column of quick 
 silver, of an equal base, and thirty inches 
 height: and, because a cubical inch of 
 quicksilver is found to weigh nearly half 
 a pound avoirdupois, therefore the whole 
 thirty inches, or the weight of the atmosr 
 
98 Atmosphere. 
 
 phere on every square inch of surface is 
 equal to 15lb. Again, it has been found 
 that the pressure of the atmosphere bal- 
 ances, in the case of pumps, &c. a column 
 of water of about 3 | feet high ; and the 
 cubical foot of water weighing just 100O 
 ounces, or 6~^.b. 34-| times 62-|, or 2158 
 Ib. will be the weight of the column of 
 water, or of the atmosphere, on a base of 
 a square foot; and consequently the 144th 
 part of this, or 15lb. is the weight of the 
 atmosphere on a square inch ; the same 
 as before. Hence Mr. Cotes computed, 
 that the pressure of this ambient fluid on 
 the whole surface of the earth, is equiva- 
 lent to that of a globe of lead of sixty miles 
 in diameter. And hence also it appears, 
 that the pressure upon the human body 
 must be very considerable ; for as every 
 square inch of surface sustains a pressure 
 of 15lb. every square foot will sustain 144 
 times as much, or 2160lb. then, if the 
 whole surface of a man's body be suppo- 
 sed to contain fifteen square feet, which 
 is pretty near the truth, he must sustain 
 15 times 2160, or 32400lb. that is near 
 14-| tons weight for his ordinary load* 
 By this enormous pressure we should un- 
 
Atmosphere. 98 
 
 doubtedly be crushed in a moment, if all 
 parts of our bodies were not filled either 
 with air or some other ela&tic fluid, the 
 spring of which is just sufficient to coun- 
 terbalance the weight of the atmosphere,, 
 But, whatever this fluid may be, it is cer- 
 tain that it is just able to counteract the 
 weight of the atmosphere, and no more : 
 for if any considerable pressure be super- 
 added to that of the air, as by going into 
 deep water ,or the like,it is always severe- 
 ly felt, let it be ever so equable, at least 
 when the change is made suddenly ; and 
 if, on the other hand, the pressure of the 
 atmosphere be taken off from any part of 
 the human body, as the hand for instance, 
 when put over an open receiver, from 
 whence the air is afterwards extracted, 
 the weight of the external atmosphere 
 then prevails, and we imagine the hand 
 strongly sucked down into the glass. 
 
 The difference in the weight of the air 
 which our bodies sustain at one time 
 more than another, is also very consider- 
 able, from the natural changes in the state 
 of the atmosphere. This change takes 
 place chiefly in countries at some distance 
 from the equator ; and, as the barometer 
 
10O Atmosphere. 
 
 varies at times from twenty-eight to thitv 
 ty-one inches, or about one tenth of the 
 whole quantity, it follows, that this diffe- 
 rence amounts to about a ton and a half 
 on the whole body of a man, which he 
 therefore sustains at one time more than 
 at another. On the increase of this natu- 
 ral weight, the weather is commonly fine, 
 and we feel ourselves what we call braced, 
 and more alert and active ; but, on the 
 contrary, when the weight of the air di- 
 minishes, the weather is bad, and people 
 feel a listlesness and inactivity about 
 them. And hence it is no wonder that 
 persons suffer very much in their health, 
 from such changes in the atmosphere es- 
 pecially when they take place very sud- 
 denly. 
 
 The weight of the atmosphere has great 
 influence on a number of physical pheno- 
 mena. It compresses all bodies, and op- 
 poses their dilatation. It is an obstacle 
 to the evaporation of fluids. The water 
 of the sea is by this cause preserved in its 
 liquid state, without which it would take 
 the vaporous form, as we see in the vacu- 
 um of the air pump. The pressure of 
 the air on our bodies preserves the state 
 
Atmosphere. 101 
 
 both of the solids and fluids ; and from 
 the want of this due pressure it is that on 
 the summits of lofty mountains the blood 
 often issues from the pores of the skin, 
 or from the lungs. 
 
 Various attempts have been made to 
 ascertain the height to which the atmos- 
 phere is extended all round the earth. 
 These commenced soon after it was dis- 
 covered by means of the Torricellian tube 
 that air is endued with weight and pres- 
 sure. And had notthe air an elastic pow- 
 er, but were it every where of the same 
 density, from the surface of the earth to 
 the extreme limit of the atmosphere, like 
 water, which is equally dense at all depths 
 it would be a very easy matter to deter- 
 mine its height from its density and the 
 column of mercury it would counterbal- 
 ance in the barometer tube : for, it having 
 been observed, that the weight of the at- 
 mosphere is equivalent to a column of 
 thirty inches or 2-| feet of quicksilver and 
 the density of the former to that of the 
 latter, as 1 to 1104O; therefore the height 
 of the uniform atmosphere would be 
 11040 times 2 feet, that is, 27600 feet, 
 or little more than 5^ miles. But the air, 
 I 
 
102 Atmosphere. , 
 
 by its elastic quality, expands and con- 
 tracts ; and it being found, by repeated 
 experiments in most nations of Europe, 
 that the spaces it occupies, when compres- 
 sed by different weights, are reciprocally 
 .proportional to the weights themselves ; 
 or, that the more the air is pressed, so 
 much the less space it takes up ; it follows 
 that the air in the upper regions of the at- 
 mosphere must grow continually more 
 and more rare, as it ascends higher ; and 
 indeed that, according to that law, it 
 must necessarily be extended to an indef- 
 inite height. At the height of 3-| miles 
 the density of the atmosphere is nearly 2 
 times rarer than it is at the surface of the 
 earth ; at the height of seven miles, 4 
 times rarer ; and so on, according to thr 
 following table. 
 
 Height in miles. Number of times rarer 
 
 3* 2 
 
 7 4 
 
 14 16 
 
 21 64 N 
 
 28 256 
 
 35 1024 
 
 42 4096 
 
 ' 16384 
 
Atmosphere,, 105 
 
 56 65536 
 
 63 262144 
 
 7O 1048576 
 
 By pursuing these calculations, it 
 might be easily shewn, that a cubic inch of 
 the air we breathe would be so much 
 rarefied at the height of 500 miles, that 
 it would fill a sphere equal in diameter to 
 the orbit of Saturn. Hence we may per- 
 ceive how very soon the air becomes so 
 extremely rare and light, as to be utterly 
 imperceptible to all experience ; and that 
 hence, if all the planets have such atmos- 
 pheres as our earth, they will, at the dis- 
 tances of the planets from one another, 
 be so extremely attenuated, as to give no 
 sensible resistance to the planets in their 
 motion round the sun for many, perhaps 
 hundreds or thousands of ages to come. 
 Even at the height of about fifty miles, 
 it is so rare as to have no sensible effect 
 on the rays of light. 
 
 Mr. Boyle in his physico-mechanical 
 experiments concerning the air, declares 
 it probable that the atmosphere may be 
 several hundred miles high ; which is 
 easy to be admitted, when we consider^ 
 what he proves in another part of the 
 
104 Atmosphere. 
 
 same treatise, viz. that the air here 
 about the surface of the earth, when the 
 pressure is taken from it, dilates into 
 10,000, and even at last into 13,679 times 
 its space ; and this altogether by its own 
 expansive force, without the help of fire. 
 In fact, it appears, that the air we breathe 
 is compressed by its own \veight into at 
 least the 13,679th part of the space it 
 would possess in vacua. But, if the same 
 air be condensed by art, the space it 
 would take up when dilated, to that it 
 possesses when condensed, will be, accor- 
 ding to the same author's experiments, 
 as 550.0OO to 1. 
 
 Our direct experiments, however, not 
 reaching to any great heights into the re- 
 gions of the atmosphere, and not know- 
 ing how far air may be expanded, we are 
 incapable of determining to what height 
 the atmosphere is actually extended. 
 
Meteors. 105 
 
 CHAP. VII. 
 
 Of the Meteors. 
 
 WE have seen that the atmosphere is 
 a vast laboratory, in which nature ope- 
 rates immense analyses, solutions, preci- 
 pitations, and combinations ; it is a grand 
 receiver, in which all the attenuated, vo- 
 latilized productions of terrestrial bodies 
 are received, mingled, agitated, combined 
 and separated. Considered in this view, 
 the atmospheric air is a chaos, an inde- 
 terminate mixture of mineral, vegetable, 
 and animal effluvia, which the electric 
 fluid is pervading and traversing contin- 
 ually. The grand changes it experiences, 
 and of which we are sensible in ex- 
 tensive spaces by the appearance of wa- 
 ter, light, or noise, are called meteors* 
 As the state of the atmosphere is ever 
 varying, the meteors assume different 
 forms ; some delighting us with their ap- 
 pearance, while others wear a terrifying 
 12 
 
1O6 Meteors. 
 
 aspect. In this repository is collected 
 the gentle dew and hoar-frost ; here 
 clouds are gathered and carried along by 
 the wind, to refresh the earth in falling 
 showers, give rise to rivers, spread vast 
 inundations of water over the fields, or 
 lay them under a covering of snow or 
 hail ; here mock-suns, mock-moons, ha- 
 loes, and rainbows make their gaudy but 
 transitory appearance ; and here the wa- 
 ter-spout, dreadful to the mariner ; here 
 rolls the dreadful thunder, here lightnings 
 dart their vivid flames, and sometimes, 
 striking upon the earth, destroy its pro- 
 ductions, fill its inhabitants with terror, 
 and sometimes strike them dead ; here 
 the auroras, or streamers, the ignesfatui, 
 or wandering fires, called also Jack with 
 the Lantern ; here falling stars, as they 
 are ignorantly termed, or fiery balls of va- 
 rious sizes, appear with splendour during 
 the gloom of night, and astonish man- 
 kind, who too often seem willing, with 
 superstitious awe, to find portentous o- 
 mens of dire calamities in these curious 
 phenomena, rather than investigate their 
 causes or discover their uses. 
 
Meteors* 107 
 
 To account for these various appear- 
 ances in a satisfactory manner, it is plain 
 that we ought to have an intimate ac- 
 quaintance with the constitution of the at- 
 mosphere ; with the nature of those pow- 
 erful agents by which it appears to be 
 principally influenced, viz. fire, light, 
 and electric fluid ; and with their peculiar 
 modes of operation and action upon one 
 another and upon the atmosphere, and 
 this in every possible variety of circum- 
 stances. Nor is even all this sufficient : 
 the various phenomena of rain, wind, 
 snow, thunder, heat, cold, &c. are known 
 to depend very much upon the situation 
 of different places on the surface of the 
 earth ; and the occasional variations are 
 with great reason suspected to proceed, 
 partly at least, from changes which take 
 place in the bowels of the earth : whence 
 we ought not only to be perfectly well ac- 
 quainted with geography, but with mine- 
 ralogy also: and that to an extent at which 
 human knowledge will probably never 
 arrive. 
 
 In a subject so very difficult, it is not to 
 be 'supposed that any thing like a certain 
 and established theory can be laid down 
 
108 Meteors. 
 
 in this little elementary work. As eva- 
 poration, however, seems particularly to 
 be concerned in the production of the me- 
 teors, we shall take a view of that opera- 
 tion of nature, the extent of which we 
 have noticed in the preceding chapter. 
 This process may be reckoned in a par- 
 ticular manner the effect of heat. Upon 
 this principle vapour is shown to be a 
 compound of water and fire ; and such it 
 is supposed to be by philosophers of the 
 highest rank. In considering this opera- 
 tion, however, as carried on by nature, 
 we shall soon find, that it proceeds in a 
 manner very different from what takes 
 place in our chemical operations. In the 
 latter, evaporation is merely the effect of 
 heat; and the process cannot go on with- 
 out a considerable degree of it. In the 
 natural way, on the contrary, the process 
 goes on under almost every degree of cold 
 we know ; the vapours ascend to a height 
 which has never yet been determined ; 
 and, from the extreme cold which they 
 sustain, show evidently that they are con- 
 nected with our atmosphere by mrans of 
 some other agent besides heat. From the 
 continual ascent of vapour indeed, if the 
 
Meteors. 109 
 
 operations of nature were of the same 
 kind with those of art, the upper parts of 
 our atmosphere would be always involved 
 in a fog, by reason of the condensation 
 of the vast quantity which continually as- 
 cends thither : but so far is this from be- 
 ing the case, that in those elevated regions 
 to which the vapours continually ascend, 
 the air is much drier than at the surface 
 of the ground. 
 
 From many experiments, indeed, it is 
 evident, that water, after being reduced 
 into a state of vapour, is capable of un- 
 dergoing a certain change, by which it 
 lays aside its fluidity entirely, and even 
 to appearance its specific gravity ; so 
 that it becomes, as far as we can judge, a 
 substance totally different from what it 
 was before. After water has attained to 
 this state, our inquiries concerning it 
 must in a great measure cease ; but as it 
 is not in the immediate product of evapo- 
 ration that rain has its source, and as va- 
 pours change their nature in the atmos- 
 phere, so as to be no longer sensible to the 
 hygrometer or to the eye, and do not be- 
 come vapour again till clouds appear, we 
 must acknowledge it to be very probable, 
 
110 Meteors. 
 
 that the intermediate state of vapour is no 
 other than air ; and that the clouds do not 
 proceed from any distinct fluid in the at- 
 mosphere, but from a decomposition of a 
 part of the air itself, perfectly similar to 
 the rest. 
 
 Granting this to be the case, and we 
 can scarcely hope for a more probable 
 conjecture on the subject, the decompo- 
 sition of the vapour will be easily accoun- 
 ted for. If by any natural process the 
 water can be con verted into air, and if the 
 latter is only water partially decomposed; 
 then, by an inversion of the process, air 
 may be instantly re-converted into water, 
 and will become visible in fog or mist, 
 or be condensed into rain, consisting of 
 greater or smaller drops, according to 
 the degree to which this inverted process 
 is carried. 
 
 It is generally supposed by meteorolo- 
 gists, from all the clouds, fogs, hail, rain, 
 and snow, being electrified, that the elec- 
 tric fluid is the agent employed in the for- 
 mation of these meteors, and that it is this 
 fluid which acts in the re-conversion of 
 air into water. This process may be par- 
 ticularly observed in the summer season, 
 
Meteors. 1 1 1 
 
 when the horizon is suddenly overcast, 
 and a copious torrent of rain ensues, which 
 cannot be from the rising of any aqueous 
 vapours at the time, but must be from a 
 precipitation of water that existed in an 
 invisible state in the atmosphere. 
 
 Water may therefore exist in air ; 1st, 
 in an invisible state, which is the case when 
 the dissolving power of air is considera- 
 ble ; 2dly, in a state of incipient separa- 
 tion, in which case it forms clouds, mists ^ 
 or fogs ; 3dly, and lastly, in a state of ac- 
 tual separation, in which case it forms ei- 
 ther rain, properly so called, or snow, or 
 hail. 
 
 Clouds are those well known assembla- 
 ges of vapours that float in the atmosphere, 
 have different degrees of opacity, which 
 arise from their extent and density, and 
 generally have pretty well defined boun- 
 daries. Their height above the surface 
 of the earth (we mean not above the moun- 
 tains) is various, but hardly ever exceeds 
 a mile or a mile and a half. In hot wea- 
 ther, or hot climates, the clouds, being 
 more rarefied, are lighter, and ascend 
 much higher than they do in colder cli- 
 mates, or colder weather : and indeed, in 
 
112 Meteors. 
 
 cold weather the clouds frequently touch 
 the very surface of the earth ; for a fog 
 may with propriety be called a cloud close 
 to the ground. 
 
 A mist is a very indefinite word. It 
 means an incipient formation of clouds, 
 or haziness ; and it often denotes a very 
 small rain, or deposition of water in par- 
 ticles so small as not to be visible singly. 
 
 The snow is formed when the atmos- 
 phere is so cold as to freeze the particles 
 of rain as soon as they are formed, and 
 the adherence of several of those parti- 
 cles to each other, which meet and cling 
 to each other as they descend through 
 the air, forms the usual fleeces of snow, 
 which are larger, (since they are longer 
 in descending, and have a greater oppor- 
 tunity of meeting) when the clouds are 
 higher than when they are lower. 
 
 The hail differs from snow in its con- 
 sisting of much more solid, and much 
 more dehned pieces of congealed water. 
 It is sui posed that the water, already 
 formed into considerable drops, is driv- 
 en and detained a considerable time 
 through a cold region of the atmosphere, 
 by the wind, which almost always accom- 
 
Meteors. 113 
 
 panics a fall of hail. But the globes of 
 ice, or hail-stones, in a fall of hail, some- 
 times far exceed the usual size of the 
 'drops of rain ; which shews that by the 
 action of the wind, the congealed parti- 
 cles must be forced to adhere to each oth- 
 er ; and, in fact, though the small hail- 
 stones are more uniformly solid and glo- 
 bular, the large ones almost always con- 
 sist of a harder nucleus, which is sur- 
 rounded by a softer substance, and some- 
 times by various distinct pieces of ice t 
 just agglutinated. Their shape is sel- 
 dom perfectly globular. 
 
 The phenomena of dew and hoar-frost 
 seem to proceed from a quantity of aque- 
 ous and undecomposed vapour which 
 always exists in the atmosphere ; and 
 which, being raised by mere heat, is con- 
 densed by mere cold, without undergo- 
 ing that process by which water is chan- 
 ged into air. 
 
 If the cold be very intense, hoar-frost 
 appears instead of dew ; which is nothing 
 more than the dew frozen after it falls 
 upon the ground, in the same manner 
 that the vapour in a warm room congeals 
 on the inside of the windpws in a frosty 
 night. K 
 
Meteors. 
 
 Lightning is found to be a flash, pro- 
 duced by the electrical fluid rush ing from? 
 one part into another ; and thunder the 
 sound of the rushing torrent, reverbera- 
 ted among the clouds. The aurora bo- 
 realis, or northern dawn, is likewise an 
 electrical phenomenon. It is a lambent 
 or flashing light, seen at night in some 
 periods more often than in others, espe- 
 cially about the poles. The fery -balls, 
 \vhich are seen shooting through the at- 
 mosphere in the night, of various magni- 
 tudes and of different forms, seem all to 
 rise from inflammable vapours, taking 
 lire from their fermenting, or effervescing 
 in the air. 
 
 The Rainbotv is one of the most sur- 
 prising of the works of God, which the 
 Hebrews called the bow of God, and the 
 Greeks the Daughter of Wonder. This 
 phenomenon is seen in the falling rain or 
 dew, and not in the cloud whence that 
 rain or dew proceeds ; it is caused by a 
 reflection and refraction of the sun's rays 
 from the globular particles of rain. The 
 face of this beautiful iris, or bow, is ting- 
 ed with all the primogenial colours in 
 iheir natural order; viz* violet^ indigo , 
 
Meteors. 115 
 
 green, yellow and red. It always 
 appears in that part of the heavens oppo- 
 site the sun. 
 
 The Halos, are circles somewhat akin 
 to the rainbow, which appear about the 
 sun and moon,and are sometimes various- 
 ly coloured. They never appear in a 
 rainy sky, but in a rimy and frosty one* 
 and are formed by the refraction of the 
 rays of light, without any reflection as in 
 the rainbow* 
 
 Mo.ck-suns and mock-moons are repre- 
 sentations of the face of the true sun an.d. 
 moon by reflection in the clouds. 
 
 The weight and pressure of the atmos- 
 pherical air have been explained in the 
 preceding chapter. We shall now exam- 
 ine the particulars relative to its progres- 
 sive motion, which we denominate wind* 
 
 Wind is a stream or current of air ; as 
 the air is a fluid, its natural state is that 
 of rest, which it endeavours always to 
 keep or retrieve by an universal equilibri- 
 um of all its parts. When, therefore, this 
 natural equilibrium of the atmosphere 
 happens by any means to be destroyed in 
 any part, there necessarily follows a mo- 
 
116. Meteors* 
 
 tion of all the circumjacent air towards 
 that part to restore it ; and this motion 
 of the air is what we call whid. 
 
 Hence, with respect to that place where 
 the equilibrium of the air is disturbed, we 
 see the wind may blow from every point 
 of the compass at the same time; and those 
 who live northwards of that point have a 
 north wind ; those who live southwards, 
 a south wind ; and so of the rest : But 
 those who live on the spot, where all these 
 winds meet and interfere, are oppressed 
 with turbulent and boisterous weather, 
 whirlwinds and hurricanes ; with rain, 
 tempest, lightning, thunder, &c. 
 
 Many are the particular causes which 
 produce winH by interrupting the equi- 
 poise of the atmosphere ; but the most 
 general causes are two, viz. heat, which, 
 by rarefying the air, makes it lighter in 
 some places than it is in others ; and cold 
 which, by condensing it, makes it heavier. 
 Hence it is, that in all parts over the tor- 
 rid zone, the air being more rarefied by 
 3 greater quantity of the solar rays, is 
 much lighter than in the other parts of the 
 atmosphere, and most of all over the 
 equatorial parts of the earth. And since 
 
Meteors. 117 
 
 trie parts at the equator are most rarefied 
 which are near the sun ; and those parts 
 are, by the earth's diurnal rotation east- 
 ward, continually shifting to the west ; it 
 follows, that the parts of the air which lie 
 on the west side of the point of greatest 
 rarefaction, and, by flowing towards it, 
 meet it, have less motion than those parts 
 on the east of the said point, which follow 
 it ; and therefore the motion of the east- 
 ern air would prevail against that of the 
 western air, and so generate a continual 
 east wind, if this were all the effect of that 
 rarefaction. But we are to consider that 
 as all the parts of the atmosphere are so 
 greatly rarefied over the equator, and all 
 about the poles greatly condensed by ex- 
 treme cold, this heavier air from either 
 pole is constantly flowing towards the 
 equator, to restore the balance destroyed 
 by the rarefaction and levity of the air ov- 
 er those regions ; hence, in this respect 
 alone, a constant north and south wind 
 would be generated. 
 
 Now it is easy to understand, that by a 
 
 composition of these two directions of the 
 
 air from the east and north, a constant 
 
 north-east wind will be generated in the 
 
 K2 
 
118 Meteors. 
 
 northern he mi sphere, and a constant south- 
 east wind in the southern hemisphere, to 
 a certain distance on each side the equa- 
 tor, all round the earth. And this case we 
 find to be verified in the general trade 
 -winds) which constantly blow from the 
 north-east and south-east, to about thirty 
 degrees on each side the equator, where 
 those parts are over the open ocean, and 
 not affected with the reflection of the sun- 
 beams from the heated surface of the land, 
 for in this case the wind will always set 
 in upon the land, as on the coast of Guin- 
 ea, and other parts of the torrid zone, we 
 know it does. 
 
 The temperature of a country with res- 
 pect to heat or cold, is increased or dim- 
 inished by winds, according as they come 
 from a hotter or colder part of the world. 
 The north and north-easterly winds, in 
 this country and all the western parts of 
 Europe, are reckoned cold and drying 
 winds. They are cold because they come 
 from the frozen region of the north pole, 
 or over a great tract of cold land. Their 
 drying quality is derived from their co- 
 ming principally over land,"* and from a 
 
 * This is not true with regard to the United States ; for here 
 the north-east wind, coming over the ocean, instead of land, 
 brirtjjs along with it so great a degree of humidity as always 
 
Meteors. 119 
 
 well known property of the air, namely, 
 that warm air can dissolve, and keep dis- 
 solved, a greater quantity of water than 
 colder air : hence the air which comes 
 from colder regions being heated over 
 warmer countries, becomes a better sol- 
 vent of moisture, and dries up with great 
 energy the moist bodies it comes in con- 
 tact with ; and, on the other hand, warm 
 air coining into a colder region deposits 
 a quantity of the water it kept in solution 
 and occasions mists, fogs,clouds,rains,&:c. 
 In warm countries sometimes the winds 
 which blow over a great tract of highly 
 heated land, become so very drying, 
 scorching and suffocating, as to produce 
 dreadful effects. These winds under the 
 name ofsolanos, are often felt in the des- 
 erts of Arabia, in the neighbourhood of 
 the Persian gulph, in the interior of Af- 
 rica, and in some other places. There are 
 likewise in India, part of China, part of 
 Africa, and else where, other winds, which 
 deposit so much warm moisture as to sof- 
 ten, and actually to dissolve glue, salts, 
 and almost every article which is soluble 
 in water. 
 
 to produce rain or snow, according to the temperature of the 
 air ; whereas, as here stated, in Europe the same wind bio wine; 
 over land, it always produces dry, fair weather. 
 
120 Meteors. 
 
 It is impossible to give any adequate 
 account of irregular winds, especially of 
 those sudden and violent gusts which come 
 on at very irregular periods, and generally 
 continue for a short time. They some- 
 times spread over an extensive tract of 
 country, and at other times are confined 
 within a remarkably narrow space. Their 
 causes are by no means rightly understood 
 though they have been vaguely attributed 
 to peculiar rarefactions, to the combined 
 attractions of the sun and moon, to earth- 
 quakes, to electricity, ^c. They are 
 called in general hurricanes, or they are 
 the principal phenomenon of a hurricane, 
 that is, of a violent storm. 
 
 Almost every one of those violent 
 winds is attended with particular pheno- 
 mena, such as droughts or heavy rains, or 
 hail, or snow, or thunder and lightning, 
 or several of those phenomena at once. 
 They frequently shift suddenly from one 
 quarter of the horizon to another, and 
 then come again to the former point. 
 In this case they are called tornadoes. 
 
 Iu some parts of the Indian ocean 
 there are winds which blow one way du- 
 ring one half of the year, and then blow 
 the contrary way during the other half 
 
Aleteor*. 121 
 
 of the year. These winds are called 
 monsoons, and owe their origin to causes 
 similar to what has been pointed out. 
 
 When the gusts of wind come from 
 different quarters at the same time, and 
 meet in a certain place, there the air ac- 
 quires a circular, or rotatory, or screw- 
 like motion, either ascending or descend- 
 ing, as it were, round an axis, and this 
 axis sometimes is stationary, and at other 
 times moves on, in a particular direction. 
 This phenomenon, which is called a 
 whirlwind, gives a whirling motion to 
 dust, sand, water, part of a cloud, and 
 sometimes even to bodies of great weight 
 and bulk ; carrying them either upwards 
 or downwards, and lastly scatters them 
 about in different directions. 
 
 The water-spout has been attributed 
 principally, if not entirely, to the meeting 
 of different winds. In that case the air 
 in its rotation acquires a centrifugal mo- 
 tion ; whence it endeavours to recede 
 from the axis of the whirl, in conse- 
 quence of which a vacuum, or, at least a 
 considerable rarefaction of air, takes place 
 about the axis, and, when the whirl takes 
 place at sea, or upon water, the water ri- 
 
122 Meteors. 
 
 ses into that rarefied place ; for the 
 same reason which causes it to ascend in- 
 to the exhausted tube, and forms the 
 water-spout or pillar of water in the air. 
 The water-spouts generally break about 
 their middle, and the falling waters oc- 
 casion great damage, either to ships that 
 have the misfortune of being under them, 
 or to the adjoining land ; for such spouts 
 are sometimes formed on a lake, or river, 
 or on the sea close to the land. 
 
 As the motion of the air has a greater 
 or lesser velocity, the wind is stronger or 
 weaker ; and it is found from observation, 
 that the velocity of the wind is various, 
 from the rate of 1 to 1OO miles per hour. 
 The following particulars respecting 
 the velocity, &?<:. of the wind are extracted 
 from a table which appeared in the 51st 
 volume of the Philosophical Transactions, 
 by Mr. J. Smeaton, the celebrated engi- 
 neer. 
 
 When the velocity of the wind is one 
 mile per hour it is hardly perceptible. 
 From 2 to 3 just perceptible. 
 
 4 5 gentle pleasant wind, or breezes, 
 
 10 15 pleasant brisk gale. 
 
 20 25 very brisk. 
 
 30 35 high winds. 
 
Meteors* 120 
 
 40 45 very high. 
 
 50 miles per hour a storm or tempest, 
 
 60 a great storm. 
 
 80 a hurrscane. 
 
 JQQ C a hurricane that tears up trees 
 
 ' \ carries buildings before it, 8cc, 
 
 The winds are of immense and indis- 
 pensable use. Besides their more ob- 
 vious effects in driving of ships, wind- 
 mills, &Pc. they preserve, by mixing, 
 the necessary purity of the air. The 
 winds, likewise drive away vapours, 
 clouds fogs, and mists from those parts 
 in which they are copiously formed, to 
 others which are in want of moisture ; 
 and thus the whole surface of the earth 
 is supplied with water. It is the winds 
 which diminish the heat, and augment the 
 moisture of the torrid zone, and produce 
 contrary effects on those of the polar re- 
 gions, so as to render those districts of 
 the globe, which the ancients deemed 
 totally unfit for the abode of man, and 
 other animals, by reason of excessive 
 heat, not only habitable, but salutary and 
 pleasing to man and beast, and yielding 
 great variety and abundance of the 
 choice productions of nature* 
 
124 Springs ) Rivers , and the Seat, 
 
 CHAP. VIII. 
 
 Of Springs, RiverSy and the Sea. 
 
 HAVING viewed water as it takes its 
 departure from the bosom of the deep 
 and forms the watery meteors, we shall 
 now survey it as it rises in the salient 
 spring, and gives birth to the gurgling 
 rill, or uniting, gives coolness to the land- 
 scape in the magnificent stream, that irl 
 its ample range fertilizes its neighbour- 
 hood. 
 
 Various have been the theories, or 
 rather hypotheses relating to the origin 
 of springs ; but it seems the general o- 
 pinion of those who have made this 
 branch of natural philosophy their study, 
 that the true principles which supply the 
 waters of fountains or springs, are mel- 
 ted snow, rain water, and condensed va*- 
 pours. 
 
Springs, Rivers, and the Sea* i2 
 
 The prodigious quantity of vapours 
 raised by the sun's heat, and otherwise, 
 being carried by the winds over the low 
 lands to the very ridges of mountains, as 
 the Pyrenean, the Alps, the Apennine, the 
 Carpathian, in Europe ; the Taurus the 
 Caucasus, Imaus and others in Asia ; 
 Atlas the Monies Lunce, or mountains 
 of the moon, with other unknown ridges 
 in Africa ; the vapours being compelled 
 by the stream of air to mount up with it 
 to the top of those mountains, where the 
 air becoming too light to sustain them, 
 and condensed by cold they strike against 
 their summits^ which causes an union of 
 their particles, and are precipitated in 
 water, which gleets down by the crannies 
 of the stone ; and entering into the ca- 
 verns of the hills, gathers, as in an alem~ 
 lie, into the basons of stone it finds, 
 which being once filled, all the overplus 
 of water that comes thither, runs over by 
 the lowest places, and breaking out by 
 the sides of the hills forms single spmgs. 
 
 Many of these springs running down 
 
 by the vallies, between the ridges of the 
 
 hills, and coming to unite, form little 
 
 rivulets, or brooks ; many of these agaia 
 
 JL 
 
1 26 Springs, Rivers, and the Sea. 
 
 meeting in one common valley, and gam- 
 ing the plain ground, being grown less 
 rapid, become a river; and many of 
 these being united in one common chan- 
 nel, make such enormous streams as the 
 Rhine, the Rhone and the Danube. 
 And it may almost pass for a rule, that 
 the magnitude of a river, or the quantity 
 of water it discharges, is proportional to 
 the length and heights of these very 
 ridges from whence the fountains arise. 
 
 The several sorts of springs observed 
 are common springs, which either run 
 continually, and then they are called 
 perennial springs ; or else run only for a 
 time, or at certain times of the year, and 
 then they are called temporary springs. 
 Intermitting springs, or such as flow 
 and then stop, and flow and stop again, 
 by regular alternations or intermissions, 
 Reciprocating springs, whose w r aters rise 
 and fall, or flow and ebb, by regular in- 
 tervals, or reciprocations of the surface. 
 
 If those reservoirs of water in the bo- 
 dy of mountains be situated where min- 
 eral ores abound, or the ducts or feeding 
 streams run through mineral earth, it is 
 easy to conceive the particles of metal 
 
Springs, Rivers-^ and the Sea. 127 
 
 will mix with, and be absorbed by the 
 water, which being saturated therewith, 
 becomes a mineral spring or well. If 
 salt, sulphur, and lime-stone abound in 
 the strata through which the water pas- 
 ses, it will then be saline, sulphureous, 
 and lime-water. If sulphur and iron 
 should both 4 abound in the parts of the 
 hill, whence the waters come, the waters 
 will partake of the warmth or heat, 
 which is. occasioned by the mixture of 
 two such substances in the earth, where 
 they are found. 
 
 Having noticed the different kinds of 
 springs, we shall say a few words respec- 
 ting the various phenomena which take 
 place in rivers. 
 
 A large collection of water which runs 
 in consequence of its gravity from at 
 higher to a lower pare of the surface of 
 the earth, in a channel generally open at 
 top, is called a river. 
 
 A river which flows uniformly, and 
 preserves the same height in the sa-ne 
 place, is said to be in a permanent state ; 
 such rivers are very rare. 
 
 The water of a river does not flow 
 with the same velocity through the 
 
128 Springs, Rivers, and the Sea. 
 
 whole width of the river. The line in 
 which the water moves with the greatest 
 velocity is called the thread of the river, 
 and this thread seldom lies in the middle 
 of the river, but it generally comes near- 
 er to one side than the other, according 
 to the nature of the impediments, and 
 the configuration of the banks. The ve- 
 locity of rivers is likewise less at the 
 bottom of their channels, than at their 
 surface ; owing to the resistance which 
 the bed makes to the water as it flows. 
 
 The running of rivers is upon the same 
 principle as the descent of bodies on in- 
 clined planes ; for water no more than a 
 solid can move on a horizontal plane, the 
 re-action of such a plane being equal and 
 contrary to gravity entirely destroys it, 
 and leaves the body at rest; here we speak 
 of a plane of small extent, and such as co- 
 incides with the curved surface of the 
 earth. But if we consider a large extent 
 or long course of water, then we shall find 
 that such water can never be at rest but 
 when the bottom of the channel coincides 
 every where with the curved surface of 
 the earth. In rivers that are made it is 
 usual to allow the fall of 1 foot in 300, but 
 
Springs, Rivers, and the Sea. 129 
 
 the declivity of those formed by nature is 
 \ r arious and uncertain. 
 
 The velocity of the water of a river 
 Ottght to increase in proportion as it re- 
 cedes from its source : but the numerous 
 causes of retardation, which occur in riv- 
 ers, are productive of very great irregu- 
 larities ; and it is impossible to form any 
 general rules for determining such 
 irregularities. 
 
 The unequal quantities of water (ari- 
 sing from rains, from the melting of snow 
 &c.) which are conveyed by rivers at dif- 
 ferent seasons, enlarge or contract their 
 widths, render them more or less rapid, 
 and change more or less the form of their 
 beds. But independent of this, the size 
 and form of a river is liable to be continu- 
 ally altered by the usual flowing of its 
 waters, and by local peculiarities. The 
 water constantly corrodes its bed where- 
 ver it runs with considerable velocity, 
 and rubs off the sand, or other not very 
 coherent parts. The corrosion is most 
 remarkable in that part of the bottom, 
 which is under the thread 'of the river, or 
 where the water descends suddenly from 
 an eminence, as in a cascade or water -fall* 
 L2 
 
1 3O Springs , Rivers, and the Sea. 
 
 The sand thus raised is deposited in pla- 
 ces where the water slacks its velocity, 
 and there by degrees an obstacle, a bank, 
 and even an island, is formed, which in 
 its turn produces other changes. Thus a 
 river sometimes forms itself a new bed, 
 or it oversows the adjacent grounds. k 
 
 In some places we find that an obstacle 
 or a bent on one side will occasion a cor- 
 rosion on the opposite bank, by directing 
 the impetus of the stream towards that 
 bank. Thus, from divers causes, whose 
 concurrence in different proportions, and 
 at different times, forms an infinite varie- 
 ty, the velocity of rivers is never steady 
 or uniform. 
 
 The following curious calculation res- 
 pecting the river Thames was made by Dr 
 Halley. " In order to estimate the quanti- 
 ty of water, which passes daily through 
 the Thames, the Doctor assumes the 
 breadth of the river at Kingston bridge, 
 (where the flood seldom reaches) to be 
 100 yards, and the depth 3 ; so that the 
 section of the channel is 300 square yards, 
 and allowing the velocity of the \vater to 
 be at the rate of 2 miles per hour, there 
 will run in 24 hours, the length of 48 miles 
 
Springs, Rivers, and the Sea. 131 
 
 or 84480 yards ; therefore 84480 x SOOzz 
 25,344,000 cubic yards, which make 203,- 
 000,000 tons which the river Thames 
 yields per diem. 
 
 The proportional lengths of course of 
 some of the most noted rivers in the world 
 are shewn nearly by the following num- 
 bers, extracted from Mr. RennelPs paper 
 71st vol. Phil. Trans. 
 
 European Rivers. 
 
 Thames 1 
 
 Rhine 5~ 
 
 Danube 7 
 
 Wolga 9| 
 
 Asiatic Rivers. 
 
 Indus 5^ 
 
 Euphrates . . 8-| 
 
 Ganges 9-| 
 
 Burrampooter 9-| 
 
 Nou Kian, or Ava River . . 9-| 
 
 Jennisea 1O 
 
 1 Oby 10! 
 
 Amoor 11 
 
 Lena 11-J 
 
 Hoanho (of China) .... 13A 
 Kian Keu (of ditto) . . , 15| 
 
 
132 Springs, Rivers, and the Sea. 
 African River. 
 
 Nile 
 
 American Rivers. 
 Mississippi ........ 8 
 
 Amazons ......... 15| 
 
 When we reflect on the immense length 
 of these rivers, and their origin, we are 
 naturally directed to the contemplation of 
 the round which water travels ; and by 
 which, without suffering adulteration or 
 waste, it is continually offering itself to 
 the wants of the habitable globe. From 
 the sea are exhaled those vapours which 
 form the clouds ; these clouds descend in 
 refreshing showers of rain, which sinking 
 deep into the earth, form springs, and 
 springs uniting form rivers, which rivers 
 in return feed the ocean. So there is an 
 incessant circulation of the same fluid; and 
 not one drop probably more or less now 
 than there was at the creation. In fact, 
 " look nature through, 'tis revolution all'* 
 wherever we turn our eyes, all seems 
 continually in a state of change or circu- 
 lation. a The sun," saith Solomon, " ari- 
 seth, and the sun goeth down, and pants 
 
Springs, River s^ and the Sea. 
 
 for the place from whence he arose ; all 
 rivers run into the sea, yet the sea is not 
 full ; unto the place from whence the ri- 
 vers came, thither they return again." 
 
 The Sea is a vast collection of waters in 
 the deep and unfathomable valleys of the 
 earth. This great abyss occupies nearly 
 three quarters of the whole surface of our 
 globe ; which has been thought by some 
 too great a proportion ; but it is probably 
 no more than sufficient to fertilize the 
 land. 
 
 The saltness of the sea is a property in 
 that element, which appears to have exci- 
 ted the curiosity of naturalists in all ages. 
 This property is very rationally judged 
 to arise from great multitudes both of 
 mines and mountains of salt, dispersed 
 here and there in the depths of the sea ; 
 the salt being continually diluted and dis- 
 solved by the waters, the sea becomes im- 
 pregnated with its particles throughout ; 
 and for this reason the saltness of the sea 
 can never be diminished. 
 
 The saltness of the sea preserves its 
 waters pure and sweet, which otherwise 
 would corrupt and stink like a filthy lake, 
 and consequently none of the myriads of 
 
1 34 Springs, River s^ and the Sea. 
 
 creatures which now live therein, could 
 then have being ; from hence also the sea 
 water becomes much heavier ; and there- 
 fore ships of greater size and quantity 
 may be used thereon. Salt water also 
 doth not freeze so soon as fresh water, 
 whence the seas are more free for navi- 
 gation. 
 
 The most re mark able thing in the sea, 
 is that motion of the water called tides. It 
 is a rising and falling of the water of the 
 sea. The cause of this is the attraction of 
 the moon, whereby the part of the water 
 in the great ocean which is nearest the 
 moon being most strongly attracted, is 
 raised higher than the rest ; and the part 
 opposite to it, on the contrary side, being 
 least attracted, is also higher than the rest. 
 And these two opposite rises of the sur- 
 face of the water in the great ocean, fol- 
 lowing the motion of the moon from east 
 to west, and striking against the large 
 coasts of the continents that lie in their 
 way, from thence rebound back again, 
 and so make floods and ebbs in narrow 
 seas, and rivers remote from the great 
 ocean. 
 
 As the earth, by its daily rotation round 
 its axis, goes from the moon to the moon 
 
Springs, Rivers, and the Sea. 135 
 
 again (or the moon appears to move round 
 the earth from a given meridian to the 
 same again) in about 24 hours, hence in 
 that period there are two tides of flood 
 and two of ebb, and this alternate ebbing 
 and flowing continues without intermis- 
 sion. For instance, if the tide be now at 
 high -water-mark, in any port, or harbour, 
 ivhich lies open to the ocean, it will pres- 
 ently subside, and flow regularly back, for 
 about six hours, when it will be found at 
 low-water-mark. After this, it will again 
 gradually advance for six hours, and then 
 return back, in the same time, to its for- 
 mer situation; rising and falling alternate- 
 ly, twice a day, or in the space of about 
 twenty- four hours. 
 
 The interval between its flux and reflux 
 is, however, not precisely six hours, but 
 about eleven minutes more ; so that the 
 time of high water does not always happen 
 at the same hour, but is about three quar- 
 ters of an hour later every day, for thirty 
 days ; when it again recurs as before. For 
 example, if it be high water, at any place, 
 to day at noon, it will be low water at ele- 
 ven minutes after six in the evening ; and 
 consequently, after two changes more, the 
 
136 Springs, Rivers, and the Sea. 
 
 time of high water the next day will be 
 about three quarters of an hour after noon; 
 the day following it will be at about half 
 an hour after one ; the day after that at a 
 quarter past two; and so on for thirty days 
 when it will again be found to be high wa- 
 ter at noon, the same as on the day the 
 observation was first made. And this ex- 
 actly answers to the motion of the moon ; 
 she rises every day about three quarters 
 of an hour later than upon the preceding 
 one; and, by moving in this manner round 
 the earth, completes her revolution in a- 
 bout thirty days, and then begins to rise 
 again at the same time as before. 
 
 To make the matter still plainer ; sup- 
 pose, at a certain place, it is high water at 
 three o'clock in the afternoon, upon the 
 day of the new moon ; the following day 
 it will be high water at about three quar- 
 ters of an hour after three ; the day after 
 that at about half an hour past four ; and 
 so on, till the next new moon ; when it 
 will again be high water about three o'- 
 clock, the same as before. And by obser- 
 ving the tides continually at the same 
 place, they will always be found to follow 
 the same rule ; the time of high water, 
 
Spri ngs, Rivers, and the Sea. 137 
 
 Upon the day of every new moon, being 
 nearly at the same hour ; and three quar- 
 ters of an hour later every succeeding day* 
 
 The attraction of the sun also produ- 
 ces a similar rising and falling of the wa- 
 ter of the ocean, but on account of its dis- 
 tance, not near so considerable as that 
 which is produced by the moon* It will 
 be readily understood that according to 
 the different situations of the sun and 
 the moon, the tides which are raised by 
 their respective attraction, will either con- 
 spire with, or counteract each other in a 
 greater or lesser degree. When they con- 
 spire together the tides rise higher, and 
 their mutual action produces what are cal- 
 led spring 1 tides* On the contrary, when 
 they counteract each other they produce 
 ntap tides. \ 
 
 From a slight consideration of what 
 has been said, we might be led to imagine 
 that the time of high water at any place, 
 would be when the moon is over the me* 
 ridian of that place. But this is by no 
 means the case ; it being usually about 
 three hours afterwards : the reason of 
 which may be shown as follows. The 
 moon 3 when she 15 on the meridian, or 
 M 
 
Springs^ Rivers*) and the Sect. 
 
 nearest to the zenith of any place, tends 
 to raise the waters at that place ; but this 
 force must evidently be exerted for a con- 
 siderable time, before the greatest eleva- 
 tion will take place ; for if the moon's at- 
 traction were to cease altogether, when 
 she has passed the meridian, yet the mo- 
 tion already communicated to the waters 
 would make them continue to ascend for 
 some time afterwards,* and therefore, they 
 must be much more disposed to ascend 
 when the attractive force is only in a small 
 measure diminished. 
 
 The waves of the sea, which continue 
 after a storm has ceased, and almost eve- 
 ry other motion of a fluid, will illustrate 
 this idea ; all such effects being easily ex- 
 plained, from the consideration that a 
 small impulse, given to a body in motion,, 
 will make it move farther than it would 
 otherwise have done. It is also, upon the 
 same principle, that the heat is not the 
 greatest upon the longest day, but some 
 time afterwards ; and that it is not so hot 
 at twelve o'clock, as at two or three in the 
 afternoon ; because there is a farther in- 
 crease made to the heat already imparted. 
 Instead of its being high water then, when 
 
Springs, Rivers^ and the Sea. 139 
 
 the moon is upon the meridian of any 
 place, it will always be found to happen, 
 as far as circumstances will allow, about 
 three hours afterwards ; and the intervals 
 between the flux and reflux, must be reck- 
 oned from that time in the same manner 
 as before. 
 
 The sun being nearer the earth in win- 
 ter than in summer, is nearer to it in Feb- 
 ruary and October than in March and 
 September ; and therefore the greatest 
 tides happen not till some time after the 
 autumnal equinox, and return a little be- 
 fore the vernal. 
 
 The tide propagated by the moon in the 
 German ocean, when she is three hours 
 past the meridian, takes twelve hours to 
 come from thence to London Bridge ; 
 where it arrives by the time that a new 
 tide is raised in the ocean. 
 
 These are the principal phenomena of 
 the tides ; and where no local circumstan- 
 ces interfere, the theory and facts will he 
 found to agree. <But it must be observed 
 that what has been here said, relates only 
 to such places as lie open to large oceans. 
 In seas and channels, which are more con- 
 fined, a number of causes concur, which 
 
140 Springs j Rivers, and the Sea. 
 
 occasion considerable deviations fiom the 
 general rule. Thus, it is high water at 
 Plymouth about the sixth hour ; at the 
 Isle of Wight about the ninth hour ; and 
 at London bridge about the fifteenth hour 
 after the moon has passed the meridian. 
 And at Batsha, in the kingdom of Ton- 
 quin,the sea ebbs and flows but once a day 
 the time of high water being at the setting 
 of the moon, and the time of low water at 
 her rising. There are also, great varia- 
 tions in the height of the tides, according 
 to the situation of coasts, or the nature of 
 the. straits which they have to pass through. 
 Thus, the Mediterranean and Baltic seas 
 have very small elevations ; while, at the 
 port of Bristol, the height is sometimes 
 near thirty feet ; and at St. Malo's it is 
 $aid to be still greater. 
 
Fvssik* 1.41 
 
 CHAP. IX. 
 
 Of Earths, Stones, Metals, Miner- 
 als, and other Fossils. 
 
 HAVING taken a view of the air 
 which surrounds, and the water which 
 diversifies the face of our globe, we will 
 now take a survey of the solid substance, 
 or body of our earth. 
 
 Those who observe the disposition of 
 the earth, as it appears in the quarrying 
 or digging of mines, find it generally ly- 
 ing in horizontal layers, or strata of dif- 
 ferent kinds, like the settlings of waters* 
 The first layer that presents itself, is most 
 commonly the bed of vegetable earth or 
 mould. With this earth the surface of 
 our globe is generally covered* It is 
 this mould which gives rooting and nour- 
 ishment to plants, so that they may stand 
 and grow in it, and it is as it were the 
 store-house from whence all the living 
 M2 
 
142 Fossils. 
 
 creatures of our world have originally 
 their provisions ; for from thence all the 
 plants have their sustenance, and some 
 few animals, and from these all other an- 
 imals. 
 
 As this affords to animals and vegeta- 
 bles their support, so the spoils of these, 
 when dead or decayed, return to the dust 
 of the ground, from whence they were 
 formed, and thus keep up an unceasing 
 circulation. 
 
 The most common disposition of the 
 layers is, that under the first earth is 
 found gravel or sand ; clay or marl ; then 
 chalk, or coal, marbles, ores, &c. This 
 disposition, however, is far from being 
 uniformly continued all over the globe ; 
 in different soils the order of these layers 
 vary. 
 
 It is wonderful the variety of produc- 
 tions which are found in the different 
 parts of our globe. In the crumbling 
 chalk, the solid marble, the dusty gravel, 
 and even the depths of the most inland 
 valleys, and on the summits of the high- 
 est mountains, we behold the spoils of the 
 ocean, exhibited under the several ap- 
 pearances of petrified fish, beds of shells^ 
 
Fossils. 143 
 
 and sea plants. The Alps, the Apen- 
 nines, the Pyrenees, Libanus, Atlas, and 
 Ararat, every mountain of every coun- 
 try under heaven, where search has been 
 made, all conspire in one uniform and 
 universal proof, that the sea has covered 
 their highest summits. If we examine 
 the earth, we shall find the mouse deer, 
 natives of America, buried in Ireland ; 
 elephants, natives of Asia and Africa, 
 buried in the midst of England ; croco- 
 diles, natives of the Nile, in the heart of 
 Germany ; shell-fish, never known but 
 in the American seas, together with skel- 
 etons of whales, in the most inland re- 
 gions of England ; trees of vast dimen- 
 sions with their roots and tops at the bot- 
 tom of mines and marls, found in regions 
 where such trees were never known to 
 grow, nay, where it is demonstrably im- 
 possible they could grow. Such are the 
 awful memorials of the great convulsions 
 and revolutions which have taken place 
 in the natural world ; of countries laid 
 under the rolling waves of the ocean ; 
 and of lands rising from the midst of the 
 waters, and becoming the habitations of 
 beasts and of men ; so transient fiiicl un 
 certain are all earthly things. 
 
144 Fossils. 
 
 The various bodies which are found 
 by digging in the earth are called fossil 
 substances \ under which are comprehen- 
 ded metals, minerals, stones of divers 
 kinds, and sundry bodies that have the 
 texture between earth and stone. 
 
 These bodies are divided into four 
 different classes by mineralogists, viz. 
 I. Earth and Stones in general ; II. Salts ; 
 III. Inflammables ; and IV. Metals. 
 
 I. Earth and Stones in general are 1st, 
 mould the support of vegetables; 2nd, 
 clays, which mixed with water harden in 
 the fire, into bricks, delf, china, &c. 3d, 
 calcareous substances, as chalks, marls, 
 limestones, marbles, convertible by heat 
 into quicklime, and gypsum into alabas- 
 ter ; 4th, talcs, which are found in flat, 
 smooth laminae ; 5th, slates also split into 
 laminae ; these with a variety of stones 
 from freestone, or sand, to granite, por- 
 phyry, flint, and substances still harder, 
 such as precious stones, are known by va- 
 rious properties, and are accordingly ap- 
 plied to different purposes ; some, in ad- 
 dition to being serviceable in building, are 
 used as whetstones ; some strike fire with 
 steel ; others are polished to glitter in the 
 
Fossils. 
 
 dress ofthe fair, or decorate the furniture 
 of the opulent ; and others, melted by fire, 
 form the transparent glass. 
 
 Although there seems to be an almost 
 infinite variety of earthly substances scat- 
 tered on the surface of this globe yet when 
 we examine them chemically, \ve find 
 that all the earth and stones which we 
 tread under our feet, and which compose 
 the largest rocks as well as the numerous 
 different specimens which adorn the cabi- 
 nets of the curious, are composed of a 
 very few simple or elementary earths, the 
 principal of which are the calcareous, si- 
 liceous, argillaceous, magnesia, terra pon- 
 derosa, and a few others which have been 
 discovered lately, but have not been much 
 examined. 
 
 Calcareous earth is found in the shells 
 of fishes, the bones of animals, chalk, 
 limestone, marble, and gypsum : but all 
 calcareous earth is supposed to be of 
 animal origin ; and beds of chalk, lime- 
 stone, or marble, are thought to have 
 been beds of shells formed in the sea, in 
 some pristine state of the earth. 
 
 Silex, or siliceous earth is the princi- 
 pal constituent part of a great number of 
 
146 Fossils. 
 
 the compound earths and stones, forming 
 the immense mass of the solid nucleus 
 of the globe. It is the base of almost 
 all the scintillating stones, such as flint, 
 rock, crystal, quartz, agate, calcedon, 
 jasper, &JV. The sand of rivers and of 
 the sea-shore, chiefly consists of it. 
 
 Argillaceous earth is found in clay^ 
 schistus, or slate, and in mica. This 
 species of earth is ductile with water, it 
 then hardens and contracts by heat, so 
 as to be of the greatest use in forming 
 brick, or stones of any required form or 
 size. 
 
 Terra ponder osa is generally found in 
 two states, viz. united to vitriolic acid, 
 when it is called calk; or to fixed air, when 
 it is called terra ponderosa aerata. This 
 earth is distinguishable by its great speci- 
 fic gravity, being four times as heavy as 
 water. 
 
 Magnesia is found sometimes pure in 
 nature, but it is generally obtained by art 
 from some of its combinations. It gives 
 a peculiar character to the substances of 
 which it forms a part. The stones which 
 contain magnesia in considerable quantity 
 ' .have generally a smooth and unctuous feel ? 
 
Fossils. 147 
 
 a greenish cast, a fibrous striated tex- 
 ture, and a silky lustre. Among them we 
 may mention talc, steatite, serpentine, 
 chlorite, asbestos, &c. Pure magnesia 
 does not form with water an adhesive duc- 
 tile mass. It is in the form of a very 
 white spongy powder and perfectly 
 tasteless. 
 
 Stones are formed by the mixtures of 
 the earths together, and of the mixtures of 
 earths with alkalies, and sometimes with 
 acids. Stones bound together by some 
 cement, form rocks. There is also a kind 
 of stones of a peculiar nature produced by 
 the fire of volcanoes. 
 
 The stones in which the acids and al- 
 kalies abound are called saline stones, and 
 the mixtures of the earths with each oth- 
 er form stones properly so called. Of 
 stones properly so called, those in which 
 the siliceous earth abounds and predom- 
 inates are very numerous ; the principal 
 of which we shall briefly notice. 
 
 Siliceous mixtures have sufficient hard- 
 ness to strike fire with steel. Of this de- 
 scription are the precious stones, rock crys- 
 tat, or quartz, felspar, silex, crysopryse^ 
 lapis lazuli, jasper, and schorl* 
 
148 fossils. 
 
 Gems, or precious stones, are of various 
 kinds. They are distinguished by their 
 hardness, weight, colour, and splendour^ 
 as well as by their property of producing 
 single or double refractions. As their 
 colour is, of all their characters, the most 
 apparent, it is according to this that we 
 shall divide them. 
 
 Red gems are the ruby, the vermillion 9 
 garnet and girasol. The ruby is a trans- 
 parent stone, the colour of which is more 
 or less red. It is distinguished into four 
 kinds, viz. the oriental ruby, the spinel 
 ruby, the balass ruby, and the Brazilian 
 ruby. 
 
 fellow gems are the topaz, hyacinth and 
 jargon of Ceylon. Of the topaz, there are 
 three kinds, the oriental topaz, the Bra^ 
 zilian topaz, and the Saxon topaz. 
 
 Blue gems are the sapphire,a.ud the aiguc 
 marine. There are two kinds of the sap- 
 phire, viz. the oriental sapphire, and the 
 Brazilian. There are also two kinds of 
 the aigue marine, the oriental and the 
 occidental. 
 
 Green gems are the emerald of Peru and 
 the chrysolite, of which there are two 
 kinds, viz. the Brazilian, accl that of the 
 jewellers. 
 
fiossik. 149 
 
 The diamond ought certainly to be pla- 
 ced among the precious stones, but it is 
 different from all those above described. 
 Its combustibility is a property entirely 
 peculiar to itself; the diamond indeed 
 burns hi the same manner as phosphorus, 
 disappears without leaving any vestiges of 
 it behind. The diamond is supposed to 
 be pure carbon, and the radical of the 
 carbonic acid. 
 
 There are several varieties of the dia- 
 mond, which differ from each other only 
 in colour ; some are^f a rose colour, and 
 others red, orange, yellow, green, blue and 
 dark coloured. 
 
 Rock-crystal and quartz seem to be the 
 same stone* The name of rock-crystal 
 is given to that which is crystallized, and 
 of quartz to that which is in a rude mass. 
 The form of these crystals is a hexadral 
 prism, terminated at one of its extremities 
 and sometimes at both, by a summit com- 
 posed of six triangular faces. In hardness 
 they are inferior to all the other gems. 
 Rock-crystal consists almost entirely of 
 pure silex. Quartz enters into the com- 
 position of granite. 
 
 Freestone is of the same i^ature as 
 N 
 
130 Fossils. 
 
 quartz. It is granulated, being composed 
 of sir. all grains of quartz, cemented toge- 
 ther, but which have very little adhesion. 
 
 Fehpar is inferior in hardness to 
 quartz. It fuses by the action of heat, 
 and forms white enamel. It is one of 
 the constituent parts of porcelain. 
 
 We may mention, under this class, ad- 
 amantine spar, which approaches near to 
 the preceding in its appearance and frac- 
 ture, but which differs from them con- 
 siderably, by its great hardness, its form, 
 and gravity. It is so exceedingly hard, 
 thai it may be employed to cut the dia- 
 mond. 
 
 Flint is a stone * which is so hard as to 
 strike fire with steel, Among the dif- 
 ferent \ rid of flints, some change their 
 colour according to the directions of the 
 rays of light, and others do not. Of the 
 former there are three, the opal, the cat's- 
 eye and iheji.s/i-et/e. 
 
 The kinds of flints which do not change 
 their colour according to the direction of 
 the rays of light, exhibit tints of more or 
 less brightness, and are susceptible of a 
 fine polish. We are acquainted with 
 eight kinds of them, viz. common Jtint^ 
 
Fossils. 1 5 ' : 
 
 petro si lex, agate, calcedony, cornelian, 
 3arcknyx,\\\zjade, and iheprasium. 
 
 Common flint posesses very little 
 transparency. All the different kinds of 
 it have a dark dull colour, and are con- 
 cave, or convex, on the fracture. They 
 do not fuse in the fire, but are calcined 
 and become white. 
 
 The distinguishing character of petro 
 silex is its semi-transparency, similar to 
 that of wax. It becomes white in the 
 fire, like the common flint, but it is more 
 fusible, as it runs without any addition. 
 
 Agate has a smooth shining fracture, 
 and will take a very high polish ; it is 
 much variegated. When exposed to 
 heat, it loses its colour, and becomes o~ 
 paque, but without fusing. 
 
 The calcedony has a milky semi-trans- 
 parency. Every kind of it takes a fine 
 polish. These stones are white, inter- 
 mixed sometimes with tints of red, yel- 
 low, and blue. 
 
 The cornelians are all either entirely^ 
 or in part, of a beautiful red colour, but 
 they lose their colour in the fire, and be- 
 come opaque. They are all susceptible 
 of a fine polish. 
 
152 Fossils. 
 
 Lapis lazuli is of a beautiful sky- 
 blue colour, sometimes mixed with white, 
 and is entirely opaque. It is sometimes 
 mixed with pyrites, from which it has 
 been supposed that it contained gold. If 
 exposed to a strong heat, it fuses, and 
 forms a sort of whitish glass ; when cal- 
 cined, it dissolves in acids into a kind of 
 jelly. Lapis lazuli, when pulverized, 
 forms that valuable colour known under 
 the name of ultramarine. 
 
 Jasper is a stone which exhibits every 
 variety of colour. It is exceedingly hard, 
 and receives a very beautiful and dura- 
 ble polish. When exposed to the action 
 of heat, it does not fuse. 
 
 Schorl is a hard stone, fusible in a 
 moderate fire, without any addition. Its 
 crystals exhibit a great variety, in regard 
 to form, appearance, texture, structure, 
 &c. Schorl, in general, is opaque ; some 
 kinds, however, are transparent, such as 
 Brazilian emerald, the peridot^ the tour- 
 malm, &?c. 
 
 The colour of schorl is various ; some, 
 kinds are black, others violet, and some 
 green. Schorl enters into the composi- 
 tion of porphyry, serpentine, the ophite, 
 granitelL and granite. 
 
Fossils. 153 
 
 The primitive earths form stones, as 
 we have mentioned, and stones united by 
 cement form those masses called rocks. 
 We shall notice the six mixtures which 
 are most commonly found in those mas- 
 ses, viz. porphyry, serpentine, ophites 
 granitell, granite, andjtint. 
 
 Porphyry is composed of felspar in 
 small fragments, of schorl, and a kind ot 
 cement, which unites ail the parts, and 
 which, in some measure, forms the base. 
 Porphyry is exceedingly hard, and diffi- 
 cult to be cut j it will, however, take a fine 
 polish. Some kinds of it are red, and 
 others green. 
 
 Serpentine is composed of the same 
 substance as porphyry. The only differ- 
 ence is, that the felspar is in larger frag- 
 ments. The colour of serpentine is vari- 
 ous ; some kinds are green, others violet, 
 some yellow, and some black. 
 
 The ophite is composed of only two 
 substances, viz. black schorl, known un- 
 der the name of ancient black basaltes, 
 interspersed with greenish felspar, which 
 forms in it long spots. This stone has 
 considerable hardness. 
 N2 
 
154 Fossils. 
 
 Granitell is also composed of two sub- 
 stances ; black schorl, and white felsper, 
 mixed with some of the green felspar. 
 The only difference then between the 
 granitelles and the ophite is, that the 
 schorl which enters into the composition 
 of the former is not of the same kind as 
 that in the latter. 
 
 Granite is composed of felspar, schorl, 
 and quartz. The colour of granite is 
 various ; it is hard, difficult to be work- 
 ed, and receives a fine polish- 
 
 Flint is a hard opaque stone, suscepti- 
 ble of a very beautiful polish. It appears 
 to be composed of concentric strata, and 
 has considerable brilliancy on its frac- 
 ture. Flints are never found in continued 
 quarries, like the other stones ; they are 
 found detached, and dispersed through- 
 out the fields. When joined by any 
 kind of cement they form pudding-stones. 
 They become decomposed in the air, for 
 they are found for the most part covered 
 with a crust, of a softer nature than the 
 interior part. Their colour is exceeding- 
 ly various ; some of them are spotted and 
 yariegated with veins, others exhibits 
 the resemblance of plumes, and even of 
 plants. 
 
155 
 
 Vakonic Productions are chiefly pum- 
 ice-stones, lava and basaltes. 
 
 Pumice-stone is real glass, in the form 
 of small greyish, white, and exceeding- 
 ly brilliant filaments. These filaments 
 always leave vacuities of greater or less 
 size between them, which occasions great 
 variations in its specific gravity. In 
 general it is lighter than water. 
 
 Lava is that burning matter which runs 
 down, in such prodigious quantities, from 
 volcanoes, when in a state of eruption., 
 and often extends to a great distance. 
 This matter is a semi-vitrified substance, 
 which appears blackish, on account of 
 its density. 
 
 Basaltes is blackish and opaque. By 
 the action of heat it may be converted 
 into glass, of a very beautiful black co- 
 lour. It often crystallizes in prisms, 
 of three, four, five, six, or seven planes- 
 Of some kinds, such as that known un- 
 der the name of touchstone, the grain is 
 exceedingly fine. 
 
 II. Of Salts. The alkalies, the acids, 
 and the combinations in which they enter 
 insufficient quantities, are called salts , 
 
156 Fossils. 
 
 or saline substances; for a saline sub- 
 stance, in its extended chemical sense, 
 means a substance that has some taste, 
 and is soluble in water. These sub- 
 stances, however, do not strictly and ex- 
 clusively belong to the fossil department, 
 but are obtained also from animal and 
 vegetable substances. They are the most 
 active agents in creation. They give 
 bodies their consistency ; preserve them 
 from corruption, and render them sa- 
 voury. 
 
 Alkalies are distinguishable by their 
 acrid, burning, and urinous taste, their 
 causticity, their singular action on the 
 skin and all animal substances, the quali- 
 ty of changing the blue colour of violets 
 to a green, and even a greenish yellow, 
 and deliquescency. We are acquainted 
 with three species, potash, soda, and 
 ammonia. The first and second have 
 been called fixed alkalies, because they 
 melt and grow red in the fire before 
 they become volatile ; the third has been 
 named volatile alkali, from possessing the 
 opposite property. 
 
 Potash is known by the following char- 
 acters :It is dry, solid, white, and very 
 
Fossils. 157 
 
 deliquescent, absorbs water with heat 
 and a peculiar faint smell, combines with 
 siliceous earth by fusion, and forms glass. 
 It is frequently found native with lime, 
 and combined with different acids ; but 
 is chiefly obtained from vegetables, in 
 the ashes of which it remains after com- 
 bustion. 
 
 Soda or the mineral alkali, is procured 
 from the ashes of sea-weed, and consti- 
 tutes the basis of sea-salt. It strikingly 
 resembles potash in form, causticity, fusi- 
 bility, deliquescency, combination with 
 earthy substances, by means of fusion, 
 action on animal substances, Sec. so that 
 it was long confounded with it, and might 
 have continued to be so, if it did not form 
 very different salts with acids, and yields 
 these acids to potash. 
 
 Ammonia, or volatile alkali, differs 
 greatly from the two preceding species 
 in its form of gas when dissolved in cal- 
 coric, in its liquid form when dissolved in 
 water, in its pungent and suffocating 
 smell, its solubility in air, &c. Am- 
 monia is procured by burning animal 
 substances ; in Egypt, (from whence, as 
 contained in sal ammoniac we till of late 
 
158 Fossils. 
 
 imported it) from camels' dung ; but 
 now from bones by distillation. 
 
 All Acids appear to be combinations of 
 oxygen or vital air, with elementary sub- 
 stances. Their taste is sour, as their 
 name imports. They change most of 
 the blue vegetable colours red, and have 
 a tendency to combine with earths, alka- 
 lies, and metallic substances. 
 
 All acids, being compounds of oxygen 
 with different substances, the former prin- 
 ciple is the cause of their resemblance and 
 common properties ; the latter, being 
 different in each, may serve to character- 
 ize each in particular. For this reason 
 those matters which are variable in acids 
 are termed their radicals, or acidifiable 
 principles. Thus all acids are combina- 
 tions of radicals, or acidifiable substan- 
 ces, different in each species, with oxy- 
 gen, which is the same in all : whence it 
 follows, that their common properties, 
 their characters as acids, depend on oxy- 
 gen, which is the acidifying principle ; 
 their particular properties, their specific 
 characters arise from their radicals. The 
 word acid, indicating the general and 
 identical nature of these substances, forms 
 their generical name, while the particular 
 
Fdssifo* 159 
 
 name of the radical contained in each may 
 with propriety designate each particular 
 acid. Thus sulphur is the radical of the 
 acid we name sulphuric, phosphorus that 
 of the phosphoric, carbon that of the 
 carbonic, and so on. 
 
 Acidifrable radicals may contain differ- 
 ent quantities of oxygen, .and under this 
 point of view they possess two states of 
 acidity. The first is that, in which they 
 contain the least possible quantity of oxy- 
 gen to render them acid. In this their 
 acidity is commonly weak, and they adhere 
 but feebly to the bases with which they 
 are capable of forming salts. The mod- 
 ern methodical nomenclature designates 
 this state of combination and acidity ^ by 
 giving the names of these weak acids the 
 termination ous. Thus w r e say the sulphu- 
 rous, nitrous, phosphorous, or acetous^ 
 acid. The second state of acids is that,, 
 in which they contain more oxygen, and 
 in general are completely saturated with 
 it. In this they have all the strength and 
 attraction they are capable of possessing 
 as acids, and the modern nomenclature 
 expresses it by the termination zc. Thus 
 we say the sulphuric, nitric, phosphoric,, 
 
16O Fossils. 
 
 or acetic, acid. With regard to the pro* 
 portion of oxygen united to acidifiable ra- 
 dicals, still greater latitude may be given 
 to the considerations presented above. 
 Each radical may be contemplated in four 
 states : 1st, containing very little oxygen 
 not sufficient to impart to it the nature of 
 an acid, and in this it is nothing more than 
 an oxyd ; such is sulphur coloured red or 
 brown, by exposure to the air, and a de- 
 gree of heat inadequate to produce infla- 
 mation ; when it is oxyd of sulphur ; 2dly 
 containing more oxygen than in the pre- 
 ceding case, and enough to become an a- 
 cid, though weak ; as in the sulphurous 
 acid ; 3dly, possessing still more oxygen 
 than in the second instance, and having 
 acquired powerful acid properties ; such 
 as the sulphuric acid ; ithly, conjoined 
 with a larger dose of oxygen than is neces- 
 sary to constitute a powerful acid, an acid 
 in ic ; when it is termed an oxygenated 
 acid, or even super-oxygenated. 
 
 The acids are generally divided into 
 mineral, vegetable, and animal, acids, ac- 
 cording to the nature of their radicals. 
 Though the first class only with propriety 
 claims notice in this place, yet for the in- 
 
Fossils. 161 
 
 formation of the reader we will enumerate 
 those belonging to each of the above 
 classes. 
 
 The miner a I acids at present known are 
 the sulphuric (formerly called the vitriolic 
 acid); the nitric acid, called also aquafor- 
 tis; the muriatic or marine acid, called by 
 artizans the spirit of salt ; the carbonic 
 acid, formerly called the acid of charcoal, 
 aerial acid, or fixed air, &c. the phospho- 
 ric acid, which is likewise an animal acid, 
 it being found amongst animal matters as 
 well as among minerals ; the acid of bo- 
 rax ; the flouric acid, formerly called the 
 acid of spar /the arsenic acid ; the moiyb- 
 die acid ; the tungstenic acid ; and the 
 chromic acid. The last four are also 
 called metallic acids. 
 
 The vegetable acids are the acetic, or 
 vinegar, the acid of tartar, the empyreu- 
 matic acid of tartar, the oxalic or acid of 
 sorrel, the acid of galls, the citric or lem- 
 on acid, the malic or acid of apples, the 
 benzoic, or the acid of benjamin, the em- 
 pyreumatic acid of sugar, the acid of cam- 
 phor, and the suberic or acid of cork. 
 
 The animal acids are, the acid of milk, 
 the acid of sugar of mu% the formic or a- 
 O 
 
162 Fossils* 
 
 cid of ants,the prussic acid, viz. the colou- 
 ring matter of prussian blue, which is ob- 
 tained from dried blood, hoofs, &c.the se~ 
 bacic or acid of fat, the bombic or acid of 
 silk- worms, the laccic or the acid of waxy 
 matter, and the zoonic, or the acid extrac- 
 ted from animal matter by means of lime. 
 
 For a more full account of these acids 
 we refer the reader to various recent pub- 
 lications, written professedly on the sub- 
 ject of chemistry. 
 
 Acids and alkalies, shew strong attrac- 
 tions for each other, and when combined 
 together in such proportion that neither of 
 them predominates, form neutral salts : 
 substances altogether dissimilar to the 
 elements of which they are composed. 
 The salt in common use for instance, is 
 formed of mineral acid and alkali ; either 
 of which, singly, would be hurtful to the 
 human body ; and the acid, in particular, 
 would be extremely pernicious. 
 
 Each acid produces with each of the 
 three alkalies a particular neutral salt. 
 The number of the last may therefore 
 be found by multiplying the number of 
 the acids which we know, by three^ the 
 number of the alkalies* 
 
Fossils* 
 
 III. Inflammables. Inflammables are 
 sulphur or bitumens. These substances 
 are both derived from the spoils of vege- 
 tables and animals. 
 
 Sulphur, known also by the name of 
 brimstone, is a simple combustible sub- 
 stance, which nature frequently presents 
 in a pure state. It is found in the earth 
 in a loose powder, or solid ; and either 
 detached or in Veins. It is met with in 
 the greatest plenty in the neighbourhood 
 of volcanoes, and is deposited as a crust 
 on stones contiguous to them. It is al- 
 so met with in mineral waters, coal-mines, 
 ?c. and also in combinations with most 
 of the metals. 
 
 The bitumens are naptha, petrol, min- 
 eral tar, asphaltum,jet, cannel-coal, min- 
 eral tallow, pit-coal, amber, &c. 
 
 Naptha is a white or yellowish white 
 substance, fluid as water, feels greasy, 
 has a penetrating smell, and burns with a 
 light flame,leavmg scarcely any residuum. 
 
 Petrol, or Petroleum, is a brown semi- 
 transparent substance ; being naptha, 
 thickened, and altered in colour and other 
 respects by the air. 
 
164 Fossils. 
 
 Mineral Tar is petrol farther altered by 
 the air, having become of the colour and 
 consistency of pitch. 
 
 Asphaltum, or mineral pitch ^ is produ- 
 ced by a still farther exsiccation or 
 drying. 
 
 Jet is a substance of a full black, hard- 
 er, and less brittle than asphalt ; and ac- 
 cording to Wtdcnrnan, is a species of 
 coal. 
 
 Cannell'Coal appears to be next to jet, 
 in gradation, of the compound mineral 
 bituminous substances. 
 
 Mineral Tallow is rarely met with, and 
 imperfectly known. It much resembles 
 tallow. 
 
 Mineral Caoutchouc is a substance 
 much resembling, in its elastic properties, 
 the substance from which it takes its 
 name. 
 
 Pit-coal, according to Mons. Gensannc 
 and others, is an earth or stone, chiefly of 
 the argillaceous genus, penetrated or im- 
 pregnated with petrol or asphalt. It has 
 also been supposed to hav 7 e been formed 
 by vegetables growing in the sea, and by 
 vast forests which have been buried br 
 subsequent revolutions, 
 
Fossils* 1 6-5 
 
 Amber is a bitumen generally of a yel- 
 low or brown colour. It is found either 
 under the surface of the ground, among 
 the clay, sand, and iron bog ore, when it 
 is called yissz/ amber, or is thrown on the 
 shore by the waters of the sea, and is then 
 called mineral amber. It is tasteless, but 
 when rubbed it yields a faint odour, and 
 manifests electric powers. 
 
 IV. Metals. We are at present ac- 
 quainted with twenty -one metallic sub- 
 stances, essentially different from each 
 other; gold,platina, silver, mercury, lead, 
 copper, iron, tin, zinc, bismuth, antimony, 
 arsenic, cobalt, nickel, manganese, molyb- 
 dena, wolfram, chrome,uranium,titanium % 
 and tellurium. 
 
 Metals exceed all other fossils in spe- 
 cific gravity ;* but there exists, in this 
 
 *The specific gravity of any body is the proportion 
 which its weight bears to the weight of another 
 body of equal bulk. The established custom is to 
 compare all bodies with water, the specific gravity 
 of which is reckoned one, or unity; so that when 
 the specific gravity of anybody, asGold,for instance, 
 5s said to be 19, Zinc 7, we mean that equal quan- 
 tities of Water, Gold, and Zinc weigh respectively 
 1, 19, and 7, be they pounds, ounces, grains, or any 
 other weights. O2 
 
166 Fossils. 
 
 respect, a remarkable difference among 
 themselves. They are completely opaque. 
 They also possess a mirror-like lustre, 
 which is one of their characteristic marks 
 and they present a convex surface when 
 melted in earthen vessels. Besides, they 
 are all insoluble in water. And by these 
 external characters, it is easy to distin- 
 guish this class from all other fossils, viz. 
 earths, salts, bitumens, and sulphur. 
 
 Metals are concealed in the earth, and 
 form ores, which existing in crevices of 
 rocks, are called ^Z72,9,and are distinguish- 
 ed into level, or into inclined, direct or 
 oblique, according to the angle they make 
 with the horizon. The part of the rock 
 resting on the vein, is termed, the roof; 
 and that on which the vein rests, the bed of 
 the vein. And the cavites made in the 
 earth, in order to extract these ores, are 
 called mines. 
 
 When nature has bestowed on metals 
 their proper metallic appearance, or they 
 are only alloyed with other metals, they 
 are said to be native. When combined, 
 as they commonly are in mines, with some 
 unmetallic substance, thev are said to be 
 mineralized ; the substance that sets them 
 
Fossils. 16f 
 
 in, that state, is called a mineratizer, and 
 the compound of both, an ore ; which term 
 is applicable when stones, or earths, con- 
 tain metallic substances, \vhether native or 
 mineralized, in a notable proportion. 
 
 Several metals are ductile and mallea- 
 ble, and their parts may be displaced from 
 each other by compression, or hammer- 
 ing, without losing their cohesion. Hence., 
 some of them may be stretched out to 
 thin laminae, or drawn into slender fila- 
 ments ; as, for instance, gold, silver, plan- 
 tina, copper, lead, tin, and iron. Other 
 metals are fragile, or brittle, and do not 
 admit of being stretched and extended ; 
 such are antimony, arsenic, cobalt, bis- 
 muth, &Pc. 
 
 All metals are fusible, but not all in 
 the same degree ; thus mercury is mel- 
 ued even by the usual temperature of our 
 atmosphere. Some metals, as tin and 
 ^ead, melt even before ignition ; others, 
 as silver, gold copper, iron, fuse only af- 
 ter being ignited. 
 
 All metals, iron and platina only excep- 
 ted, melt on a sudden, as soon as they 
 are heated in a due degree ; but iron 
 and platina grow soft before they fuse.. 
 
168 Fossils. 
 
 and on this depends their very useful 
 property of becoming capable of being 
 -welded. 
 
 Almost all metals may be combined 
 by fusion into one seemingly homogene- 
 ous mass, and from thence various metal- 
 lic mixtures, metallic alloys, or composi- 
 tions arise ; which, for their particular 
 properties, are often of very great utility. 
 
 If metals be continued in fusion, the} 
 lose their brilliancy, and become an opaque 
 powder, or what is termed a metallic oxyd 
 or calx. 
 
 All metals, gold, silver, and platina, 
 excepted, are oxyded or calcined in fire 
 with access of air. In this respect, those 
 which cannot be oxyed by fire have recei- 
 . ved the name of noble metals, to distin- 
 guish them from the rest which may be 
 calcined that way, and are called base 
 metals. 
 
 Gold is a noble metal, of a yellow colour; 
 and, after platina, the heaviest of metals. 
 Its specific gravity is from 19,258 to 19,- 
 640. Its hardness and elasticity are in- 
 considerable ; but its tenacity is great ; 
 and with regard to ductility, or malleabili- 
 ty it exceeds all other metallic substances. 
 
Fossils. 169 
 
 Platma is a noble metal of a white co- 
 lour ; for which reason some called it 
 white gold. In Europe it is known only 
 since the middle of the present century, 
 and brought to us in small irregularly-fig- 
 ured grains, but which are impure, and 
 mostly contaminated with iron. Pure 
 platina exceeds all other metals, even gold 
 In specific gravity, which is found to reach 
 21,061. It is ductile and malleable ; its 
 hardness and tenacity are greater than 
 those of gold, and it admits of being 
 welded. 
 
 Silver is a noble metal, of a white color 
 whose specific gravity is variable from 
 1O,474 to 10,542 ; it is very malleable 
 and ductile, and of a moderate hardness. 
 It fuses in a heat of less intensity than is 
 required by gold ; it is fixed in fire, and is 
 not affected by water nor air, remaining 
 in both unaltered ; but by sulphureous 
 vapours it is very soon tarnished. 
 
 Mercury, or quicksilver is a base metal 
 of a white colour. Its specific gravity is 
 upon an average 13,674 it is the most 
 fusible of all known metals, and continues 
 in the fluid state even in the cold temper- 
 ature of our winters j it congeals only at 
 
1 70 Fossils. 
 
 40 Farenheit, and shews then some tena- 
 city and ductility. 
 
 Lead is a base metal of a bluish white 
 colour. Its specific gravity is from 11,- 
 352 to 11,445 ; it is considerably ductile 
 but little tenacious and hard, hence it may 
 be extended in thin plates by the hammer 
 but not drawn into fine wire. It has 
 scarcely any elasticity. 
 
 Bismuth is a yellowish or reddish white 
 metal, of a foliated fracture, and very 
 brittle, it being even reducible to powder 
 by the hammer. Its specific gravity is 
 from 9,670 to 9,822. It is somewhat 
 harder than lead but more fusible. 
 
 Nickel is a greyish white metal, of a 
 specific gravity between 9,OOO and 9,333 
 It is malleable, and very compact or firm. 
 
 Copper is a base metal, of a brownish 
 red colour ; sonorous, very tenacious, 
 ductile, and malleable ; of a considerable 
 compactness ; of a moderate hardness 
 and elasticity ; and of an hackly fracture. 
 Its specific gravity varies from 7,788 to 
 9,000. 
 
 Arsenic is a brittle metal, and on the 
 recent fracture, of a mean colour, betwixt 
 tin- white and lead-grey ; but, on expo- 
 
Fossils. in 
 
 sure to air, it soon turns black and dull. 
 Its specific gravity is 8,310; its hardness 
 is somewhat considerable, and seemingly 
 surpassing that of copper. But its duc- 
 tility is so little, and its brittleness so great 
 that it is readily converted into powder by 
 the hammer. 
 
 Of all metals Iron exhibits the most 
 varieties and deviations. Its differences 
 in colour, density, fracture, tenacity, duc- 
 tility, and degree of fusibility, are uncom- 
 monly great. Soft and malleable iron has 
 a greyish-white^ colour, a light grey, fi- 
 brous,hackly fracture. Its specific gravity 
 at a mean rate is 7,700 ; its hardness is 
 not great, but its malleability and tenaci- 
 ty are considerably so ; and it has this 
 characteristic property, not possessed by 
 other species of this metal, that whether 
 cold or ignited, it may be extended, forg- 
 ed, and bent, without breaking. 
 
 By cast or crude iron, that metal is 
 understood, which is obtained by the 
 first smelting of iron-ores. Such iron is 
 distinguished from ductile iron by its re- 
 fusing to be extended and forged by the 
 hammer, whether cold or ignited, by its 
 brittleness ,aud by its fusing in strong heat 
 
172 Fossils. 
 
 
 in open fire, without addition, whereby 
 it is rendered capable of being cast into 
 moulds. The colour of crude iron is 
 more or less of a pale grey. 
 
 Steel differs from both the ductile and 
 the crude iron. Its distinguishing pro- 
 perty is, that when it is tempered^ that 
 is to say, when it is hastily plunged in 
 cold water while ignited to redness, it be- 
 comes harder, more brittle, and inflexi- 
 ble ; and that, before this tempering or 
 hardening, it is ductile, whether cold or 
 ignited ; and also, that after having been 
 hardened, it reassumes its ductility by a 
 fresh igniton and gradual cooling, with- 
 out quenching. Its colour is a light grey, 
 its fracture finely granular. 
 
 Cobalt is a base metal, of a lead grey 
 colour, brittle and hard, and of specific 
 gravity from 7,000 to 7,700. This metal 
 is rather of difficult fusion. 
 
 Tin is a base metal of a white colour, 
 a little more verging to blue than that of 
 silven -It is very soft, pretty malleable 
 and tractable ; its compactness and elas- 
 ticity are but slight. When broken or 
 bent, or when compressed betwen the 
 teeth, it makes a peculiar crackling noise 7 
 
Fossils* 173 
 
 which is one of its characteristic proper-* 
 toes. The specific gravity of tin is varia- 
 ble from 7,216 to 7,331. Its gravity de- 
 creases in the ratio of its purity. 
 
 Zinc is a white metal, of a radiated 
 texture, changing into the foliated* It is 
 of a middle kind betwen the malleable 
 and brittle metals, and may be extended 
 into thin laminae, at least between metal- 
 lic cylinders in rolling mills. The spe- 
 cific gravity of this metal is from 6,862 
 
 Antimony has a white colour, resem- 
 bling that of tin, a foliated radiated text- 
 ure, and is very brittle. Its specific gra- 
 vity varies from 6,702 to 6,860. In the 
 air it loses little of its metallic splendour 
 and it does hot rust in the strict sense of 
 the word. 
 
 Manganese is a white, hard, brittle me- 
 tal, whose specific gravity is found to be 
 from 6,850 to 7,OOO. 
 
 Molybdena has a pale lead-grey colour, 
 a metallic lustre, and a laraellated fracture 
 it is very soft, and marks paper easily, 
 leaving a shining trace. Its specific gra- 
 vity is between 4,138 and 4,569. 
 
 Wolfram is a metallic substance of modr 
 P 
 
Fossil*. 
 
 ern discovery, and of a particular kind, 
 whose calx or oxyd is of a yellow colour, 
 and one of the constituent parts of the fos- 
 sil, called tungsten. 
 
 Another distinct metallic substance on- 
 ly a few years since discovered by Klap- 
 roth, is the Uranium. The oxyd of u- 
 ranium has a lemon-yellow colour, is fix- 
 ed in fire, and infusible when alone. Ig- 
 nition changes its colour to a brownish 
 grey. 
 
 We are likewise indebted to Klaproth 
 for the discovery of the new metal called 
 by him Titanium or Titanite. It is con- 
 tained in the mineral called red shoerl as 
 a native oxyd. The colour of the perfect 
 oxyd of titanium is red ; but when kept 
 In violent ignition upon coals, and by a 
 greater degree of disoxydation, it gradu- 
 ally assumes a yellowish, bluish, and 
 blackish hue. 
 
 Tellurium is a metal of a white colour 
 like tin, inclining to lead-grey. It is brittle 
 and friable ; possesses a lamellar texture, 
 and considerable metallic lustre ; is one 
 of the most easily fusible metals, and ex- 
 hibits a crystallized surface when slowly 
 cooling after fusion.- Its specific gravity 
 is 6,1 15. 
 
fossils. 175 
 
 Chrome is a white metal, inclining to 
 grey, very brittle, and crystallizable at an 
 elevated temperature in feathered fila- 
 ments on the surface. 
 
 The minerals to be found in England 
 are both curious and useful. Amber, jet y 
 vitriol and allum are found in considera- 
 ble quantities ; our canal coal approaches 
 nearly to the beauty of jet, and even our 
 common coal fire for firing is of a superior 
 nature. The English earth and gravel 
 are of the best quality; and we have stone,, 
 slates, flags, and other fossils necessary 
 for building in great abundance. Tin is 
 another article in which England, from 
 the time of the Phenicians had always had 
 the pre-eminence- The county of Corn- 
 wall alone produces more than all the 
 world besides. Our lead ore is richer 
 than in other countries, runs more fluently 
 in the fire, require^ less trouble and ex- 
 pense in working, and is when wrought 
 very fine and ductile* Our black lead or 
 wadd, found in Cumberland, is a mineral 
 of great use and value in several branches 
 of trade and arts. Copper and iron are 
 also found here in great plenty, and seve* 
 
176 
 
 Fossils. 
 
 ral ores of these metals, particularly in 
 Anglesey, have of late been discovered, 
 and brought into use, which were un- 
 known before the recent improvements in 
 chemistry. 
 
Plants* 
 
 . X. 
 
 Of Vegetables or Plants 
 
 NEXT to the earth itself, we may con- 
 sider those that are maintained on its 
 surface ; which though they are fastened 
 to it, yet are very distinct from it : and 
 those are the whole tribe of vegetables 
 or plants. These may be divided into 
 three sorts, herbs, shrubs^ and trees. 
 
 Herbs are those plants, whose stalks 
 are soft, and have nothing woody in them, 
 as grass, sowthistle, and hemlock. Shrubs 
 and trees have all wood in them ; but 
 with this difference, that shrubs grow 
 not to the height of trees, and usually 
 spread into branches near the surface of 
 the earth ; whereas trees generally shoot 
 up in one great stem or body, and then, 
 at a good distance from the earth, spread 
 into branches ; thus, gooseberries and 
 currants, are shrubs ; oaks and cherries, 
 are trees. 
 
 P2 
 
Plants. 
 
 Numerous are the works which have 
 been written, especially in later times, on 
 the science -of botany, and various sys- 
 tems, or classifications of plants have 
 from time to time been proposed; but 
 the sexual system of Linnaeus is at pre- 
 sent generally received. This naturalist 
 has cjrawn a continued analogy between 
 the vegetable economy and that of the 
 animal ; and has derived all his classes, 
 orders, and genera, from the number, 
 situation, and proportion of the parts ot 
 fructification. In twenty-four classes, 
 he has comprehended every known genus 
 and species. In considering a plant 
 with a view to its characteristics, or dis- 
 tinguishing features, it is divided by Lin- 
 naeus into the following parts, making so 
 many outlines, to which the attention o 
 the botanical observer must be directed ; 
 1. Root ; 2. Trunk ; 3. Leaves ; 4. Props 
 5. Fructification ; 6. Inflorescence. 1* 
 The root consists of two parts, the caudex 
 and the radicula. The caudex, or stump, 
 is the body or knob of the root from which 
 the trunk and branches ascend, and the 
 fibrous roots descend, and is either solid, 
 bulbous, or tuberous 5 solid, as in trees* 
 
Plants. 179 
 
 and other examples ; bulbous, as in tulips 
 &c. tuberous, as in potatoes, &c. The 
 radicula is the fibrous part of the root, 
 branching from the caudex. 2. The trunk, 
 which includes the branches, is that part 
 which rises immediately from t\ir caudex 
 in either herbaceous, shrubby, or arbor- 
 escent, and admits of several other dis- 
 tinct! ons,according to its shape,substance, 
 surface, &?c. 3. The leaves are either 
 sirs pie, as those that adhere to the branch 
 singly, or compound, as when several ex- 
 pand from one footstalk. Leaves are far- 
 ther described by various terms indicative 
 of their form and outline. 4. The props 
 those external parts which strengthen 
 support, or defend, the plants on which 
 they are found, or serve to facilitate some 
 necessary secretion ; as the petlious, or 
 footstalk of the leaf; the pedunculus, or 
 footstalk of the flower, the stipula, or 
 husk, that is, the small leaves that gener- 
 ally surround the stalk at its divisions ; 
 the cirrfiU8,or tendril; ihepubes, or down; 
 the arma, or defensive weapon, as thorns* 
 5. The fructification, or mode, of fruit- 
 bearing. 6. The inflorescence, or mode by 
 which the flowers are joined to the seve- 
 ral peduncles. 
 
180 Plants. 
 
 In plants there is an infinite diversity; 
 some aquire a long succession of ages to 
 bring them to perfection, while others at- 
 tain their full maturity in a few hours ; 
 some are of immense magnitude, while 
 others are of an inferior stature, descend- 
 ing by gradation till they become too mi- 
 nute to be cognizable by the senses. The 
 mighty baobob of Senegal, described by 
 Adanson,whose stem is 75 feet in circum- 
 ferance, stands a stately monument on the 
 face of the earth for many thousands of 
 years ; while the mushroom, which it 
 much resembles in form, springs up in a 
 day, perfects its seeds, and is withered to- 
 morrow ; and when we carry our views 
 still farther, into that immense profound 
 of minuteness which has but of late been 
 partly laid open to us by the invention of 
 the microscope ; into the class of mosses, 
 which are in some measure cognizable by 
 the naked eye, and still farther into the 
 more minute class of plants denominated 
 mould, which, even in those of the largest 
 species, are too small to have their parts 
 cognizable by the naked eye, and which, 
 when viewed by the best microscopes, 
 discover a series of existences diminish 
 
Plants. 181 
 
 ing by a regular gradation, like stars in 
 the galaxy under the best telescopes, till 
 they are lost in the infinity of minuteness, 
 leaving every reason to believe, that, 
 could the magnifying powers of our in- 
 struments be augmented a thousand fold, 
 we should still find ourselves as far from 
 discovering the termination of this series 
 of infinite diminution as we were at the 
 commencement of our imperfect survey. 
 The world that we see, therefore, seems 
 to be but a very small part of that which 
 exists ; our feeble optics are capable of 
 taking in scarcely a point of that universe 
 which surrounds us ; and our imperfect 
 understandings can scarcely obtain a 
 glimpse of that infinite power and wisdom 
 which regulates the whole. Among this 
 infinity of objects, however, we can clear- 
 ly perceive the most perfect regularity 
 and order pervading every part; and 
 that all the operations of nature proceed 
 with invariable steadiness to effect the 
 purposes for which they have been de- 
 signed. 
 
 Thus we see that all animate objects, 
 from the largest that has been discovered 
 on this globe, to the smallest that can 
 
182 Plants. 
 
 
 ever be made to be perceptible to us, in- 
 variably proceed from other animated ob- 
 jects of the same kind, although they ap- 
 pear at times under such disguised forms 
 as not to be at first sight cognizable by us. 
 This rule applies to vegetables as well as 
 animals. The plant of mould, which, 
 even when it hath attained its full stature, 
 can scarcely be perceived as a point under 
 our microscopes of the highest magnify- 
 ing power, we have every reason to be 
 satisfied, produces its seeds in as regu- 
 lar order, which ripen at their appointed 
 period with the same regularity as those 
 of the mighty baobob ; but while this re- 
 mains a stately monument upon the sur- 
 face of this earth, and sees thousands of 
 generations of men succeed each other, 
 and successively shelter themselves un- 
 der the protecting shade of its spreading 
 branches, we observe the mould spring up, 
 perfect its seeds, scatter them in imper- 
 ceptible myriads in the air, and disap- 
 pear within the short space of one hour : 
 so that during the short period of our 
 existence here many myriads of genera- 
 tions of mould have succeeded each other. 
 Time itself then, when the universe is 
 
Plants. 183 
 
 viewed as a whole, can only be consider- 
 ed as a relative object. Shall man then, 
 a being who cannot comprehend fully the 
 nature of a single object around him, 
 dare proudly to lift up his face, and pre- 
 tend to decide concerning possibilities 
 and the powers of nature ! His proper 
 province is to be humble and adore ! 
 
 The plants with which we are best ac- 
 quainted may be arranged into three 
 grand divisions. The first are those 
 whose roots and stems remain for many 
 years, which comprehends all the varie- 
 ties of trees and shrubs. These, for the 
 most part, require several years to bring 
 them to a state of puberty (if that phrase 
 may be admitted)^ when they begin to 
 put forth flowers, and perfect their seeds ; 
 after which time they usually continue 
 to produce an annual crop of flowers and 
 seeds for a long period of time ; the fruit 
 in general succeeding the flowers, and 
 perfecting their seeds in the same year ; 
 but to this rule there are several excep- 
 tions. In a few instances the seeds do 
 not attain to muturity in the same sea- 
 son that the flower is produced ; but ? 
 continuing upon the tree the whole win* 
 
184 Plants. 
 
 ter in an immature state without being 
 killed, they advance in the second season, 
 and then only perfect their seeds; instances 
 of which are to be found in the juniper 
 and orange-tree. Others continue to ad- 
 vance for several years, as usual, with- 
 out showing fruits ; and when at length 
 they reach that state of maturity, they 
 then flower, and, having perfected their 
 seeds, they decay and flower no more, 
 dying down like annual plants ; an exam- 
 ple of which is to be found in the cab- 
 bage-tree of tropical regions. Some are 
 scarcely ever (perhaps never) known to 
 produce either flowers or seeds of any 
 sort, but admit of being propagated by 
 some other means ; instances of which 
 are to be found in the English elm of our 
 own country, the jack, or bread-fruit tree 
 of India ; and many others. 
 
 The second division of plants are- those 
 that have a perennial root, from which 
 stalks are sent forth annually, which us- 
 ually produce flowers, perfect their seeds 
 in the summer, and die down to the 
 ground at the approach of winter. The 
 stems of these are for the most part of a 
 similar structure and consistence with 
 those of 
 
Plants. 18* 
 
 The third class, or annuals, from the 
 seeds of which, if sown in the spring^ 
 stalks spring up which produce flowers 
 and seeds the same season ; after the 
 perfecting of which the stalks decay and 
 die entirely away. Biennials can only 
 be viewed as a diversity of these, that 
 have not sufficient length of season to 
 bring them to perfection in one year. 
 
 Whether distinctions similar to these 
 take place among those minute tribes of 
 plants which we call microscopical, it 
 exceeds our power at present to deter- 
 mine. From the short period of their 
 existence, we have been generally in- 
 clined to think that they are all similar 
 in quality to annuals ; that is to say, that 
 they flower but once, and die down im- 
 mediately after they have once perfected 
 their seeds* Yet, who dares pretend to 
 say, that the plant of mould ^ which ex- 
 ists perhaps but one of our hours, may 
 not produce in that period many thou- 
 .sands of successions of ripe seeds, each 
 of which has taken its due season to ri- 
 pen like those of the baobob, which 
 flourishes on our globe for hundreds of 
 ages! for the same infinite power which 
 
1&6 Plants. 
 
 has decreed that the total duration o 
 this plant shall be Jimited to an hour, 
 mny have also decreed, that the matura- 
 tion of its seeds, and the com- lotion of a 
 period that to it should be similar to that 
 of our year, should be accomplished i 
 the thousandth part of a second of ou 
 time. 
 
 All plants seem to grow in the sam 
 manner: the genial warmth of the sun 
 the refreshment of the rains, the sam 
 soils appear t--> suit their respective spe 
 cies ; and, ?ha superficial glance, the 
 srem to have the same common parts 
 chemical analysis discovers the same con- 
 stiturnt principles in all, that is to say 
 calcareous earth, oil, water, and air, wit" 
 a portion of iron, to which they ovvethei 
 beautiful colours. Yet, although compo- 
 sed of similar materials, their juices to 
 the eye, and to the taste, appear as vari- 
 ous as their forms. The soporific milk 
 oi the poppv , the acrid but equally milky 
 juice of the spungc, the acid of the sorrel, 
 the saccharine sap of the sycamore and 
 mapie, and the resin of the tribe of pines-, 
 bear no resemblance to each other. 
 
 The inward structure of plants is as 
 
 i 
 
Plants. 187 
 
 regular and various as their external 
 forms are elegant and well-proportioned. 
 The root, trunk, branch, leaf, flower, 
 fruit and seed, have each its peculiar 
 character and form. No part in the con- 
 texture of the smallest fibre is unfinish- 
 ed but is formed with the most minute 
 exactness. The seeds of plants have the 
 appearance of shells, unlike in form, and 
 diversified with spots and stripes. Eve- 
 ry seed possesses a reservoir of nutri- 
 ment, designed for the growth of the 
 future plant. This is the matter prepar- 
 ed by nature for the reproduction and 
 continuation of the whole species. This 
 nutriment consists of starch, mucilage, 
 or oil, within the coat of the seed, or of 
 sugar and subacid pulp in the fruit, which 
 belongs to it. The sections of the vaii- 
 ous kinds of trees are crossed with the 
 greatest number of regular figures which 
 the imagination can conceive. The lines, 
 which form the texture of fir-trees, 
 are distant ; but those of oak are close 
 and compact. And this difference of 
 texture may serve to account for their 
 greater or less solidity, and the difference 
 of time requisite for them to arrive at 
 maturitv. 
 
188 Plants. 
 
 The nourishment of plants is perform 
 ed chiefly by the tender fibres of the roots, 
 which being spread under-ground, im- 
 bibe from the moist earth juice fit for 
 their nutriment, which they transmit to 
 the other parts. The impulse by which 
 the juices rise seems to be capillary at- 
 traction ; for the roots of all vegetables 
 are supposed but bundles of capillary 
 tubes : and whether we consider earth, 
 water, salt and oil, as the food of plants - 
 or, with Kirwan, that coal is essential to 
 that food or with Ingenhouz, that it is 
 vital air decomposepl into fixt air and 
 azote ; still that food must be formed by 
 water into an emulsion, capable of being- 
 acted upon by capillary attraction ; and 
 as all roots are but assemblages of these 
 tubes, there can be little doubt but their 
 attraction supplies the plant with its first 
 food ; though other causes must assist 
 in carrying it to the tops of the tallest 
 trees, such as dilatation and contraction, 
 by the successive heat and cold of day 
 and night, the muscular action of vascu- 
 lar rings round the tubes irritated to con- 
 traction by the stimulant sap, &c. The 
 anterior bark conducts the nourishment 
 supplied by the earth. 
 
, 
 
 Plants. 180 
 
 After the sap has thus ascended to the 
 eaves, it there undergoes certain altera- 
 tions, and is converted into another fluid, 
 called the succus proprhis, or peculiar 
 juice ; which, like the blood in animals^ 
 is afterwards employed in forming the- 
 various substances found in plants. The 
 leaves may therefore be considered as 
 the digesting organs of plants, and as 
 equivalent in some measure to the sto- 
 mach and lungs of animals. The leaves 
 consequently are not mere ornaments ; 
 they are the most important parts of the 
 plant. Accordingly we find, that when- 
 ever we strip a plant of its leaves, we 
 strip it entirely of its vegetating powers 
 till new leaves are formed ; for when the 
 leaves of plants are destroyed by insects, 
 they vegetate no longer, and their fruit 
 never makes any further progress in ri- 
 pening, but decays and dries up, 
 
 Leaves on one side draw nutriment 
 from the air, and perspire on the other ; 
 for plants, as well as animals, perspire, 
 and, in both cases, this function is essen- 
 tial to health. The quantity they per- 
 spire varies, according to the extent of 
 the surface from which it is emitted, the 
 
temperature of the air, the time of the 
 day, and the humidity of the atmosphere. 
 Leaves form the greatest part of the sur- 
 face, and it is found that the quantity of 
 these very materially affect the quantity of 
 perspiration ; and this process is increas- 
 ed or diminished, chiefly, in proportion 
 to the increase or diminution of the fo- 
 liage of vegetables. The degree of heat 
 in which the plant is kept also varies the 
 quantity of matter perspired ; this being 
 greater, in proportion to the greater heat 
 of the surrounding atmosphere. The 
 degree of light has likewise considerable 
 influence in this respect ; for plants uni- 
 formly perspire most in the forenoon, 
 though the temperature of the air, in 
 which they are placed, should be unvari- 
 ed. A plant also exposed to the rays of 
 the sun, has its perspiration increased to 
 a much greater degree than if it had 
 been exposed to the same heat under the 
 shade. Finally, the perspiration of veg- 
 etables is increased in proportion as the 
 atmosphere is dry, or, in other words, 
 diminished in proportion as the atmos- 
 phere is humid. The more vigorous 
 and healthy the plant, the more copious 
 the perspiration j this function, like the 
 
Plants. 191 
 
 est, depending much on the vital ener- 
 rgy. Excessive perspiration seems to 
 hurt, and even sometimes to destroy, veg- 
 etables ; defective perspiration is equal- 
 ly injurious. It is also found, that this 
 function is performed, chiefly, if not al- 
 together, by the leaves and young shoots* 
 That it may be properly carried on, all 
 leaves are deciduous ; in those trees cal- 
 led ever-greens, there being a constant 
 succession of leaves, to prevent the or- 
 gan of perspiration from becoming rigid* 
 A quantity of moisture is absorbed by 
 plants, when exposed to a humid atmos- 
 phere. This absorption, as well as the 
 perspiration, is performed by the leaves $ 
 but in what manner has not yet been as- 
 certained. Experiments made by M, 
 Guettard shew, that perspiration is more 
 considerable from the upper, than from 
 the under, surface of the leaves. 
 
 Plants in general are known to receive 
 and transpire more, in equal time, than 
 large animals. It has been found by ac- 
 curate calculation, and repeated experi- 
 ments, that a plant of the sun-flower re- 
 ceives and perspires in twenty-four hours 
 seventeen times more than a man, 
 
192 Plants. 
 
 Some botanists have conceived that 
 plants, as well as animals, have a regular 
 circulation of their fluids. Others thinfc 
 this very improbable. On both sides, 
 recourse has been had to experiments, 
 and from these conclusions perfectly op- 
 posite have been deduced ; so that no 
 certain conclusion can be drawn on this 
 head. 
 
 Light has great effect on vegetation. 
 Plants that grow in the shade, or in dark- 
 ness, are pale, and without colour ; and 
 the more they are exposed to the light, 
 the more colour they acquire. 
 
 Vegetables are not only indebted to 
 light for their colour ; their taste and 
 odour are derived from the same source. 
 Hence it happens that hot climates are 
 the native countries of perfumes, odori- 
 ferous fruits, and aromatic resins. 
 
 The action of light on the organs of 
 plants, causes them to pour out streams 
 of pure air from the surfaces of their 
 leaves, while exposed to the sun ; where- 
 as, on the contrary, when in the shade, 
 and at night, they emit air of a noxious, 
 quality. 
 
 The various secretions of vegetables^ 
 
Plants. 193 
 
 as of odour, fruit, gum, resin, wax, hon- 
 ey, &c. seem brought about in the same 
 manner as in the glands of animals ; the 
 tasteless moisture of the earth is convert- 
 ed by the hop-plant into a bitter juice ; 
 as by the caterpillar in the nutshell the 
 sweet kernel is converted into a bitter 
 powder. While the power of absorption 
 in the roots and barks o vegetables is 
 excited into action by the fluids applied 
 to their mouths like the lacteals and lym- 
 phatics of animals. 
 
 The individuals of the vegetable world 
 may be considered as inferior or less 
 perfect animals ; a tree is a congeries of 
 many living buds, and in this respect re- 
 sembles the branches of coralline, which 
 are a congeries of a multitude of ani- 
 mals. Each of these buds of a tree has 
 its proper leaves or petals for lungs, pro- 
 duces its viviparous or its oviparous off- 
 spring in buds or seeds ; has its own 
 roots, which extending down the stem of 
 the tree are interwoven with the roots of 
 the other buds, and form the bark, which 
 is the only living part of the stem, is an- 
 nually renewed, and is superinduced up- 
 on the former bark, which then dies, and 
 
194 Plants. 
 
 with its stagnated juices gradually hard- 
 ening into wood forms the concentric 
 circles, which we see in blocks of timber, 
 which annual rings serve as natural marks 
 to distinguish the age of trees. 
 
 The botanist follows nature into her 
 most retired abodes, and views htr in 
 her simple state, and native m^-stv. 
 He remarks some of her productions 
 figured by cultivation in gardens, wh 
 amid all the varieties of thr apple and 
 the pear ? however distinguished by th^ir 
 colour, size and taste, he observes, that 
 there is but one original species c;f each, 
 and that they have respectively but one 
 radical character. He beholds the won- 
 derful prodigality of nature, even in the 
 composition of the common daisy, which 
 consists of more than two hundred flow- 
 ers, each including its respective corolla, 
 germ, pistil, stamina, and seed, as per- 
 fectly formed as those of a complete lily, 
 or hyacinth. And he sees this diversity 
 as fully illustrated in the different sorts 
 of grass, a term which, although it com- 
 monly conveys only one notion to tfae Vul- 
 gar mind, and one object to the undis- 
 ce^rning eye, consists of five hundred dif- 
 
Plants. 195 
 
 ferent species, each formed with infinite 
 beauty and variety. From others he par- 
 ticularly distinguishes the elegant brizct 
 media, so common in the fields, and so 
 remarkable for its delicate hair-like stem, 
 trembling at every breeze ; the anthoxan- 
 ihum odoratum, which gives its fragrance 
 to the new-mown hay ; and the stipa 
 pennata with its waving plumes resem- 
 bling the feathers of the bird of paradise* 
 The botanist enjoys a pleasing and inno- 
 cent amusement, most agreeably com- 
 bined with a love of rural retirement, 
 and which gives a new and growing inter- 
 est to every w r alk and ride, in the most 
 delightful season of the year. Indeed 
 man cannot contemplate the vegetable 
 creation without recalling the idea of 
 beauty, sweetness, and a thousand charms 
 that captivate the senses. The perfume 
 of the rose and the stately magnificence 
 of the forest successively catch his atten- 
 tion and delight him* 
 
 The number of species of plants alrea- 
 dy known is about twenty-five thousand ; 
 and botanists suppose that double that 
 number, at least, remain to be discoveredo 
 
 The different vegetable productions are 
 
196 Plants 
 
 no less useful than numerous. The pur- 
 poses to which the trees of Britain are ap- 
 plied are well known, from the flexible 
 willow, which forms the basket, to the 
 hardy oak, which composes the most sub- 
 stantial parts of a ship of war, guards the 
 British islands from foreign invasion, and 
 displays to the most remote countries the 
 greatness of our maritime power. All 
 possess different qualities, adapted to 
 their different purposes. The meanest, 
 and in their appearance the most unplea- 
 sant, have their use ; even the thistle is 
 not only the food of some animals, but is 
 serviceable in making glass. There is 
 scarcely a plant which although rejected 
 as food by some animals is not eagerly 
 sought by others. The horse yields the 
 common water hemlock to the goat, and 
 the cow the long-leafed water hemlock to 
 the sheep. The goat again leaves the 
 aconite, or bane-berries to the horse* 
 The euphorbia or spurge, so noxious to 
 man, is greedily devoured by some of the 
 insect tribes. The aloe is a magazine of 
 provisions and of implements to the In- 
 dians who inhabit the banks of the Ohio 
 and the Missisippi. Some plants, a* 
 
Plants. 19? 
 
 rhubarb and opium, alleviate the tortures 
 of pain ; and some, as the quinquina, or 
 Peruvian bark, can subdue the rage ot the 
 burning fever. Wheat, the delicious and 
 prolific grain which gives to the inhabi- 
 tants of the northern world their whole- 
 some nutriment, grows in almost every 
 climate, Where excessive heat or other 
 causes prevent it from cojning to perfec- 
 tion, its place is amply supplied by the 
 bread-fruit, the cassavi-root and maize, 
 and more particularly by rice, which is the 
 common aliment of that great portion of 
 mankind who inhabit the warm regions 
 of the earth. Every meadow in the ver- 
 nal season brings forth various kinds oi 
 grass ; and this spontaneous and most 
 abundant of all vegetable productions re- 
 quires only the labour of the husbandman 
 to collect its harvest. The iron-wood^ 
 solid as marble, furnishes the Otaheitean 
 with his long spear and massy club. The 
 wild pine of Campeachy retains the rain- 
 water in its deep and capacious leaves not 
 less for the refreshment of the tree itself, 
 than of the thirsty native of a burning 
 soil. The cocoa of the East and West 
 Indies anwers many of the most usetul 
 R 
 
198 Plants. 
 
 purposes of life to the natives of a warm 
 climate. Its bark is manufactured into 
 cordage and clothing, and its shell into 
 useful vessels ; its kernel affords a pleas- 
 ant and nutritive food, and its milk a cool- 
 ing beverage ; its leaves are used for cov- 
 ering houses, and are worked into bas- 
 kets ; and its boughs are of service to 
 make props and rafters. The rein-deer 
 of the Laplander, so essential to his sup- 
 port and subsistence, could not survive 
 through the tedious winter, without the 
 lichen rangiferinus, which he digs from 
 beneath the snow. On the bleak moun- 
 tains of the north, the pine, the fir, the ce- 
 dar, and man of the resinous trees grow, 
 which shelter many from the snows by 
 the closeness of their foliage, and furnish 
 him in winter with torches and fuel for his 
 fire-side. The leaves of those evergreen 
 trees are filliform, and thus are adapted to 
 reverberating the heat, and resisting the 
 violent winds which beat on elevated situ- 
 ations* All these productions, and the 
 various trees which produce cork and 
 emit rosin, turpentine, pitch, gums, and 
 balsam, either supply some constant ne- 
 cessity, obviate some inconvenience? or 
 
Plants. 199 
 
 contribute to some use or gratification of 
 the natives of the soils where they grow,,, 
 or of the inhabitants of distant climate^ 
 
200 Animals. 
 
 CHAP. XL 
 
 Of Animals. 
 
 WE are now come to consider the last, 
 the noblest and the most beautiful part of 
 the creation : the creatures for whom this 
 earth seems to have been entirely form- 
 ed, and for whose repast or use the whole 
 of its unintelligent productions appear to 
 have been brought forth ; these are the 
 animated tenants of our globe. 
 
 When we compare animals and vegeta- 
 bles together, each in their most perfect 
 state, nothing can be easier than to dis- 
 tinguish them. The plant is confined to 
 a particular spot, and exhibits no marks 
 of consciousness or intelligence ; the ani- 
 mal, on the contrary, can remove at plea- 
 sure from one place to another, is posses- 
 sed of consciousness, and a high degree 
 of intelligence. But on approaching the 
 
eont 
 
 \7pcrf 
 
 Animals. 201 
 
 contiguous extremities of the animal and 
 vegetable kingdom, these striking differ- 
 ences gradually disappear, the objects ac- 
 quire a greater degree of resemblance, 
 and at last approach each other so near- 
 ly, that it is scarcely possible to decide 
 whether some of those species which are 
 situated on the very boundary, belong to 
 the animal or vegetable kingdom. In- 
 deed we find the vegetable, animal, and 
 mineral kingdoms so closely connected, 
 like the links of a chain, that there is no 
 possibility of finding a disjunction in any 
 part, nor saying with precision where the 
 one ends and the other begins, so nearly 
 do they approach each other in the ex- 
 tremes of each class* 
 
 The term animal, in a general sense, 
 is applied to every thing that is supposed 
 to be alive to the sensations of pain and 
 pleasure. Under the name of animal, 
 therefore, are included men, quadrupeds, 
 ibirds, fishes, reptiles, and insects. Ani- 
 xnal literally means a living- thing- ; but 
 plants live. Linnaeus has formed a cli- 
 max of the grand departments of crea- 
 tion. Stones grow ; vegetables grow and. 
 live ; animals grow, live* and feel. 
 R2 
 
202 Animate* 
 
 Various are the corporeal forms, and 
 great are the peculiarities of organization 
 of the different animals which inhabit the 
 globe ; and equally various are their in- 
 tellectual powers; beginning with man, 
 who forms the highest link in the chain, 
 and descending by an almost impercepti- 
 ble diminution of mental powers, through 
 an innumerable series of existences, and 
 ending at last in mere animation alone, 
 with a seeiuing privation of all mental 
 perception whatever. 
 
 As an animal, man is strikingly dis- 
 tinguishable from the rest of the crea- 
 tures of the earth, on account of the in- 
 genuity with which he eir ploys the pro- 
 ductions of nature for his accommoda- 
 tion and comfort. He is also particular- 
 ly distinguishable by the originality of 
 his ideas. Instincts, in common with 
 brutes, make up a part of his character; 
 but he is principally the creature of ex- 
 perience ancl reflection. When an infant 
 comes into the world it is the most help- 
 less of all creatures ; no danger alarms 
 it, nor can it make the smallest effort to 
 preserve itself. A tiger may approach 
 it without occasioning terror ; nor would 
 
Animals. 203 
 
 it, attempt to screen itself when the lion's 
 mouth is opened to devour it. The voice 
 of the mother is not understood for ma- 
 ny weeks ; and it is but by slow degrees 
 that it acquires knowledge,in consequence 
 of the gradual developement of its rea- 
 soning faculties ; but as its progress is 
 more slow, so its ultimate attainments 
 are proportionally greater than that of 
 other animals. The chicken, within the 
 first eight clays of its life, seems to have 
 made nearly the whole mental acquire- 
 ments it is ever capable of attaining; but 
 no period of human life can be assigned 
 when the mental progress of man is at a 
 stand. Man alone is able to form an idea 
 of an abstract proposition or to reason 
 about distant occurrences. He alone can 
 reason from consequences to remote 
 causes, and can from the creature trace 
 an idea of the Creator. A sense of reli- 
 gion, then,is the characteristic peculiarity 
 which decisively marks a separation be- 
 tween man and all other animals. 
 
 But as the understanding of man and 
 the structure of his frame will occupy the 
 following chapters, we will in this con- 
 fine ourselves to a view of the other parts 
 o f a n i t\i at e d n at ur e 
 
Animals. 
 
 Animals, like vegetables, differ in their 
 sizes and powers, with respect to the 
 places of their growth. Those produc- 
 ed in a dry sunny soil, are strong and vi- 
 gorous, though not luxuriant : those again 
 produced in a warm and moist climate 
 are luxuriant and tender, and much lar- 
 ger than those produced in other coun- 
 tries ; as in the internal parts of South 
 America and Africa, particularly in the 
 former place, where the earth worm is 
 near a )*ard long, and an inch thick ; the 
 Serpents sometimes forty feet in length ; 
 the Bats as large as Rabbits ; Toads big- 
 ger than Ducks ; :md the Spider equal in 
 size to the English Sparrow. But in the 
 frozen regions of the north, animals are 
 scarce ; and what few there are, except 
 the .Bear, are not above half the size of 
 those in the temperate zone. 
 
 Animals are also found to vary consid- 
 erably according to their food or climate ; 
 and there are but few of the animal 
 kingdom, (and these are they that are 
 the most useful) which are found capa- 
 ble of attending man in his peregrina- 
 tions' over the globe. In uncultivated 
 nature, the animal kingdom exceeds the 
 
Animate. 205 
 
 vegetable ; -but, in a state of improve- 
 ment, tbe interest of man so directs it, 
 that the vegetable kingdom should gain 
 the ascendancy ; for on a review of the 
 animal and vegetable world, we find but 
 few animals, which are intrinsically ser- 
 viceable to man ; while on the other hand, 
 numbers of them are noxious to his food, 
 and inveterate enemies to his interest. 
 But among the vegetable world, very few 
 are noxious ; and the greater part of 
 them yield either food, medicine, or some 
 other valuable article. Therefore, it al- 
 ways has, and will remain to be, the in- 
 terest of man, to diminish the number of 
 animals, and increase that of vegetables ; 
 and in assistance to his endeavours, pro- 
 vidence has wisely ordered it, that one 
 animal shall subsist on another ; for were 
 they to live entirely on vegetables, myri- 
 ads would soon become extinct, for want 
 of support. 
 
 The number of animals, which are im- 
 mediately serviceable to man, (exclusive 
 of the smaller, among the birds and fish- 
 es, which serve for food) does not extend 
 to one hundred ; while, we are acquaint- 
 ed with no less than twenty thousand ; 
 
2O6 Animak. 
 
 and even this great number, compre- 
 hends but a small portion of animated na- 
 ture. Not only the earth, air, and sea, 
 teem with myriads of living creatures, 
 but almost every vegetable, and each sin- 
 gle leaf, is covered with an endless num- 
 ber of inhabitants, whose various forms 
 and properties have afforded matter of 
 astonishment to the microscopic obser* 
 ver. 
 
 Animals are nourished by food, taken 
 in at the mouth, digested in the stomach, 
 and thence, by fit vessels, distributed 
 over the whole body ; but of the process 
 by which the various vegetable produc- 
 tions, which form the food of a large por- 
 tion of animals, is converted into part of 
 the animal, we are totally ignorant. That 
 this change does take place we know, 
 but in what manner we know not any 
 more than the animals themselves do, 
 whose natural organs perform, unknown 
 to them, the functions that are necessary 
 for producing these changes. 
 
 The greatest part of animals have five 
 senses, viz. seeing, hearing, smelling, 
 tasting, and feeling. These, and the way 
 of nourishment of animals, we shall more 
 
Animals, 207 
 
 particularly consider, as they are com* 
 mon to man with beasts, in the following 
 chapter. 
 
 Animals are generally divided into 
 male and female, and some are both male 
 and female, and are called hermaphro- 
 dites, as the earth worm and some others* 
 With regard to their mdnner of propa- 
 gation, they are divided into oviparous? 
 bringing forth eggs ; and viviparous^ 
 bringing forth their young alive. 
 
 Linnaeus divides animals, according to 
 their internal structures. Some have the 
 heart with two ventricles, and hot, red 
 blood : viz. Quadrupeds and Birds ; 
 others have the heart with one ventricle, 
 and cold, red blood, viz. Amphibia and 
 Fishes ; the former being furnished with 
 lungs, and the Fishes with gills. Some 
 have the heart with one ventricle^ and 
 cold, white serum, viz. Insects and 
 Worms ; the former being furnished 
 with feelers, and the latter with holders* 
 All quadrupeds, which have teats, are 
 distinguished by their teeth. These 
 form the following seven orders ; the 
 Primates or Principals, which have four 
 suiting teeth in each jaw ; the Brutse or 
 
208 Animals. 
 
 Brutes, which have no cutting teeth ; the 
 Ferae or Wild Beasts, which have six cut- 
 ting teeth in each jaw; the Glires, or 
 Dormice, which have two cutting teeth 
 both above and below ; the Pecora, or 
 Cattle, which have no cutting teeth above, 
 and six or eight below ; the Belluse. or 
 Beasts, properly so called, which have the 
 fore teeth blunt ; and the Cetse, or those 
 of the Whale kind, which have cartilagi- 
 nous teeth. This is the brief outline of 
 this celebrated Naturalist's arrangement, 
 the names of the different animals, and 
 their respective classes, occupying no 
 less than two large octavo volumes ; but 
 the natural division of animated nature, is 
 universally allowed to be the five follow- 
 ing classes ; Quadrupeds, Birds, Fishes^ 
 Insects, and Amphibious Animals ; tho' 
 it must be confessed that this distribution 
 is not exactly defined by nature ; as there 
 are many animals whose form and quali- 
 ties render it difficult to reduce them to 
 any one of these classes. 
 
 I. QvMdrupeds. Quadrupeds are a large 
 and useful class of animals, whose gener- 
 ic characters are these ; their bodies are 
 covered with hair: they have four feet; 
 
Animals. 209 
 
 they are viviparous ; and the females 
 suckle their young. 
 
 Quadrupeds are the most important 
 creatures to man, and deserve his atten- 
 tion more than the inhabitants of either 
 the air, or the water. They inhabit the 
 same soil with man ; and among them are; 
 found beings possessing a greater share 
 of instinct than the inhabitants of either 
 air or water ; they breathe through their 
 lungs, like the human species ; like these 
 they are viviparous ; they have also warm 
 red blood circulating through their veins ; 
 and, however mortifying the reflection to 
 human pride, many of them, both in their 
 internal and external form, bear a strong 
 resemblance to man the interior struc- 
 ture of some of the ape kind, so nearly 
 resembles that of the human kind, that 
 anatomists can scarcely discover where 
 the peculiarity exists. 
 
 Though the characters of Quadrupeds 
 are so obvious, yet as all the parts of na- 
 ture are united together, to form one 
 grand whole ; there are several species, 
 which seem to be of an equivocal na- 
 ture, and which form the links, uniting 
 different animals together ; as the Bat 
 S 
 
2TO Animals. 
 
 and Porcupine, the former of which pos- 
 sesses wings, and the latter quills, like 
 Birds ; the Armadillo is covered with a 
 hard shell, by which it seems to partake 
 of the nature of Insects, or Snails ; and 
 the Seal and the Morse, though evidently 
 of the quadruped kind, are furnished with 
 fins, and reside almost constantly in the 
 water. 
 
 Quadrupeds, like all other animals,, 
 are wisely adapted by Providence to 
 their respective situations and natures* 
 Those which turn up the ground in pur- 
 suit of their food, have sharp snouts ; 
 others, which require a keener scent, as 
 dogs, particularly those of the chase, have 
 long noses,, whereby the olfactory nerves 
 are more perfect : while others, of a ra~ 
 pncious nature, have short thick noses, 
 whereby their jaws have a greater mus- 
 cular power, as those of the Lion ; and 
 all granivorous animals have a strong 
 tendinous ligament, extending from the 
 head to the middle of the back, to ena- 
 ble them to hold down their heads to 
 the ground ; the fore teeth of these ani- 
 mals are also edged, for the purpose of 
 cutting their food ; but those of carni* 
 
Animals. %'il 
 
 vorous animals are sharp, and serve 
 rather as weapons o defence, In both,, 
 however, the surfaces of the grinding 
 teeth are unequal and jagged, locking in- 
 to each other when the jaws are brought 
 into contact. The stomach of carnivo- 
 rous animals is also small and glandular ; 
 and affords such juices as are best adap- 
 ted to digest and macerate its contents ; 
 but those animals which subsist on a 
 vegetable diet, have four stomachs ; all 
 which serve as so many laboratories, to 
 prepare the food for the nourishment of 
 the body ; and, in general, granivorous 
 animals, whose food is easily procured, 
 have large capacious stomachs, and ca- 
 pable of great dilation ; whereas carni- 
 vorous creatures have the stomach more 
 contracted, and the intestines curtailed^ 
 whereby they are enabled to subsist for 
 a longer time without food. Strong 
 large animals, which are neither tbrmed 
 for pursuit rior flight, as the Elephant, 
 Rhinoceros, Sea- Horse, &c. have thick 
 massy legs, to support their unweildy bo- 
 dies. While Deers, Hares, and other 
 creatures, whose safety depends on flight, 
 and who are beset by numberless ene- 
 
212 Animals 
 
 mies, have long, slender, hut muscular 
 legs. Those formed for a life of rapa- 
 city have their feet armed with sharp 
 claws, which in some species are retrac- 
 tile, as those of the Cat ; and, on the 
 contrary, peaceful animals are generally 
 furnished with hoofs, which often serve 
 sis weapons of defence ; and the feet of 
 those which subsist on fish, have mem- 
 branes betwen the toes, the better to 
 enable them to pursue their prey in the 
 watery element. 
 
 The larger species of Quadrupeds are, 
 in general, the most harmless and inof- 
 fensive ; and, as if sensible of their own 
 innocence, they possess the most courage ; 
 while the more rapacious animals are in- 
 ferior to those in size, and also in cour- 
 age ; and, except the Dog, there is no 
 carnivorous quadruped, that will volun- 
 tarily attack another animal, when the 
 odds is against him. Thus nature has 
 furnished the most inoffensive animals 
 with superior size and strength ; and op- 
 posed to them the carnivorous kinds, 
 which possess more cunning and agility, 
 whereby an equilibrium is preseved be- 
 t v/een the numbers of the different kinds. 
 
Animals* 
 
 The carnivorous animals are, in gen- 
 eral, confined to their retreats during the 
 day, and commit their depredations by 
 night ; when the forest resounds with the 
 tremendous roar of the Lion, the hide- 
 ous yell of the Tiger ; the barking of the 
 Jackal; the dismal cry of the Hyaena; 
 and the hissing of the Serpent. Most 
 of these kinds of animals take their prey 
 by surprise from some ambush, where 
 they lay in wait, more than by a regular- 
 pursuit. There are some, however, which 
 pursue in companies, mutually encoura- 
 ging each other by their cries, as the Jack- 
 al, Syagush, Wolf, and Dog. Carnivorous 
 animals will sometimes devour the lesser 
 rapacious species ; but they generally pre- 
 fer the flesh of granivorous creatures, and 
 commit their devastations among the 
 peaceful domestic flocks and herds. The 
 most defenceless creatures have different 
 methods of providing for their safety* 
 Some find protection in the holes they 
 form in the earth ; others are enabled to 
 escape their pursuers by flight ; others 
 again unite for their mutual defence, and 
 gain, by numbers, what they want indivi- 
 dually in strength ; and, lastly, other? 
 S2 
 
Animals. 
 
 avoid their enemies, by placing some ot 
 their own company as centinels, to warn 
 them of the first approach of danger ; a 
 duty in which they are seldom negligent, 
 and for the neglect of which they are in- 
 variably punished by the rest. 
 
 II. Birds. Birds, next to quadrupeds 
 seem to demand our attention. The 
 generic characters of this class of animals 
 are these ; the body is covered with fea- 
 thers, and furnished with two legs, two 
 wings, and a hard horny bill ; and the fe- 
 males are oviparous. 
 
 Birds are infinitely more numerous in 
 their different kinds than quadrupeds 9 
 but still less so than Fishes. They seem 
 designed by providence for a solitary life; 
 and though inferior to the brute creation 
 in the powers of attack and defence, they 
 possess a greater faculty of escape; and the 
 greater part of them immediately elude 
 their enemies of the quadruped and rep- 
 tile nature, by an aerial escape ; for which 
 all parts of their bodies seem admirably 
 adapted ; the external form of the body 
 being sharp before ; swelling gradually, 
 and terminating in a 1 *ge spreading tail, 
 which renders it buoyant, while the fore 
 part cleaves the air- 
 
Animals. 
 
 The clothing of these animals is exactly 
 suited to their manner of life. The feath- 
 ers all tend backwards, and neatly and 
 closely fold over each other, which answer 
 the triple purposes of warmth, speed and 
 security. Those placed next the skin are 
 furnished with a warm soft down ; while 
 the exterior ones are arrayed with double 
 beards, longer at one end than the other, 
 and which consist of thin little laminae, 
 disposed in regular lines, and perfectly 
 even at their edges. The shaft of each 
 feather is formed of a thin hollSw tube, 
 which answers the purposes of strength 
 and lightness ; the upper part being filled 
 with a soft pith, to afford nourishment 
 to the beards. They are so placed, that 
 the largest and strongest, or those of the 
 wings and tail, have the greatest share of 
 duty to perform in flight. The upper 
 external side of each single filament, in 
 the beard of the feather, is furnished with 
 hairs on its edges, which lock into those 
 of the next filament, and thus form an en- 
 tire, but light, smooth surface. Birds are 
 also furnished with certain glands upon 
 their rumps, which contain a quantity of 
 oilj which they press out w ith their beaka*, 
 
Animals* 
 
 and rub over their feathers; in order to 
 smooth them, and enable them to turn off 
 the water. Aquatic Birds, as the Duck, 
 Goose, &c. have a greater quantity of this 
 oil; but those who live principally under 
 cover, and seldom expand their wings, 
 have a less proportion of it ; as the com- 
 mon Hen, whose feathers are impervious 
 to every shower of rain. 
 
 Birds possess a perfection of sight far 
 superior to that of either man or brute, 
 which is necessary for their safety and 
 support? Were it less perfect, Birds of 
 rapid flight would strike against every ob- 
 ject in their way ; and be unable to disco- 
 ver their proper food at a distance. The 
 Kite darts on its prey, from the greatest 
 heights to which it ascends; and the Hawk 
 will discover a Lark, at a distance too 
 great for human perception. 
 
 Aquatic Birds have webbed feet, or 
 membranes between their toes, to assist 
 them in swimming; other Birds have their 
 toes disjoined, the better to enable them 
 to catch their prey, or cling to the branch- 
 es of trees. Birds, with long legs, have 
 also long necks, to enable them to pick up 
 their food ; but some Aquatic Birds, as 
 
Animals-. 217 
 
 the Swan and Goose, have long necks and 
 short legs. 
 
 Birds are destitute of urinary bladders 
 yet they have large kidneys and ureters, 
 by which the secretion of urine is perfor- 
 med, and then carried away with the oth- 
 er excrements, in one common canal ; by 
 which means they are less obnoxious to 
 diseases than quadrupeds, who drink much 
 and have a separate passage for the ejec- 
 tion of the fluid excrement. 
 
 The greater number of Birds pair at the 
 approach of spring ; and the compact en- 
 tered into is inviolably observed, for that 
 season at least; but some species enter 
 into this connection for years, and even 
 for life. 
 
 All Birds are oviparous, and the Hens 
 of some species will lay eggs though they 
 be not accompanied by the Male ; as the 
 common domestic Hen ; but eggs of this 
 kind are always sterile, never producing a 
 live ani mal. Every bird builds its nest in 
 such a manner, and with such materials, 
 as best to answer its own purpose and sit- 
 uation ; thus the Wren, which lays a great 
 number of eggs, requires a very warm 
 yies t ' 9 as her body is not sufficiently large ta 
 
218 Animals. 
 
 cover the whole of thrm ; but the Crow and 
 Eagle are less solicitous in the warmth of 
 their nest, as the small number of eggs 
 they lay, and largeness and heat of their 
 bodies, afford the eggs sufficient warmth. 
 The same Bird also, when in a cold cli- 
 mate, lines its nest with more care and 
 warmer materials than in a warmer cli- 
 mate. The male likewise of most birds, 
 during the season of incubation, supplies 
 th' j place of the female, in her absence 
 from the eggs ; and supplies her with 
 food during the time of her sitting. 
 
 Those birds which are hatched early 
 in the season, always prove more vigo- 
 rous and strong, than such as have been 
 delayed till the middle of summer. The 
 number of eggs, which a bird will lay, 
 is not exactly ascertained ; but it is well 
 known, that a female Bird, which would 
 have lain but two or three eggs at most, 
 will, on her eggs being removed, lay above 
 ten or a dozen. A common Hen, if pro- 
 perly fed, will produce above a hundred 
 eggs, from the beginning of spring to the 
 end of Autumn. Nature has wisely or- 
 dered it, that the smallest and weakest 
 birds ; and in general, all those which are 
 
Animals,, 219 
 
 most serviceable to man, are the most 
 prolific : while the strong and rapacious 
 kinds are marked with sterility. 
 
 Birds are in all countries, longer lived 
 than the brute creation ; the Linnet will 
 often live fourteen or fifteen years ; the 
 Bullfinch tw.enty ; the Goose fourscore ; 
 while Swans, Eagles, and some others, 
 have been known to live two, or even three 
 hundred years. 
 
 The number of species of Birds, which 
 mankind has rendered domestic, are but 
 few, as the Peacock, Turkey, common 
 Hen, Guinea-Hen, Pigeon, Swan, Goose, 
 Duck, and Guinea-Duck, being only nine, 
 while the number of all the species known 
 exceed fifteen hundred. 
 
 III. Amphibious animals are all those 
 who are capable of living either on land 
 or in the water. They are furnished with 
 lungs and air bladders, adequate to this 
 purpose. Such are the Frog, Castor^ 
 Otter, Tortoise, Sea-Galf, Alligator, &c* 
 
 Numbers of insects, particularly of the 
 Fly kind, appear to be amphibious ; Gnats 
 always drop their eggs in water, where 
 the young are hatched, and live after the 
 manner of fishes ; till at length they un~ 
 
20 Animals. 
 
 dergo a metamorphosis, take wing, quit 
 their natural element, and become inhabit- 
 ants of the air. 
 
 IV. Fishes. Fishes are a class of crea- 
 tures that appear, both in structure and 
 sagacity quite inferior to other animals ; 
 though capable of enduring famine an 
 amazing length of time, they appear 
 most voracious creatures ; a ceaseless 
 desire for food seems the ruling impulse 
 of their actions ; and their life one con- 
 tinued scene of violence or evasion. 
 
 Most fishes present the same external 
 form ; sharp at both ends, and bulky in 
 the middle ; which shape is most conve- 
 nient for their passage through the wa- 
 tery element. Mankind have imitated 
 this form, in the construction of their 
 marine vessels ; but the progress of such 
 machines is far inferior to that of fishes ; 
 any of which, will, with ease, outstrip a 
 ship in full sail ; play around it, loiter 
 behind, and overtake it. 
 
 The instruments of motion in these 
 animals are the fins ; of which the gener- 
 al complement is two pair, and three sin* 
 gle fins ; though some fish possess more, 
 and many less than this number. The 
 
Animals. 221 
 
 pectoral fins, are placed at some distance 
 behind the opening of the gills ; and are 
 generally strong and large ; answering 
 the same purpose, to a fish, as wings do 
 to a bird in the air ; namely, pushing 
 the body forward, like the oars to a boat. 
 They also serve to balance the body of 
 the fish, and prevent the head from sink- 
 ing, which it would otherwise do. The 
 ventral fins are placed under the belly, 
 towards the lower part of the body ; 
 these are always extended flat on the 
 water, in all situations ; and serve to 
 raise or depress the body of the animal, 
 rather than assist his progression. The 
 dorsal fin, is situated along the ridge of 
 the back ; and serves to keep the fish in 
 equilibrium, and also assists it in its velo- 
 city. This fin is very large, in all the 
 flat fish ; the pectoral fins of which are 
 proportionally less. The anal fin, ex- 
 tends from the anus to the tail, and serves 
 to keep the body of the animal upright, 
 or in a vertical direction. In some fish- 
 es, as before observed, the tail is hori- 
 zontal, and in others perpendicular. - 
 Thus equipped, these animals have the 
 xiiost rapid motions ; and perform voy- 
 T 
 
222 Animals. 
 
 ^ges, of upwards a thousand leagues is 
 one season. 
 
 Fish are also furnished with a slimy 
 glutinous matter, which overspreads the 
 whole body, and defends them from the 
 corosslve quality of the water. Beneath 
 this matter, some have a strong covering 
 of scaks, which, like a coat of armour, 
 protects the body from injuries. Be- 
 neath which, again, there is an oily sub- 
 stance, which supplies the animal with 
 the necessary warmth and vigour. 
 
 Fishes possess most of the senses in 
 an inferior degree to land animals. 
 Their sense oi smelling, (though furnish- 
 ed with nostrils) is less perfect, than in 
 the other parts of animated nature, 
 as must be evident from the nature of the 
 fluid they inhabit ; this sense in them 
 can only act, from the action of the fluid, 
 tinctured with the odour of the object^ 
 upon the olfactory nerves within, in the 
 same manner as the palates of other an- 
 imals discover tastes. Their sense of 
 taste must also be very imperfect ; their 
 palate being of a hard bony nature ; 
 whereas, in quadrupeds who possess 
 this sense in an exquisite degree, this 
 
Animals. 223 
 
 organ is very soft and pliant. From 
 this indiscrimination, fish will frequent- 
 ly swallow the plummet, as well as the 
 bait. Their sense of hearing is still 
 more defective, if they possess this facul- 
 ty at all, as is evident from the frequent 
 experiments which have been made. 
 No fish, except the whale kind, have the 
 least appearance, on dissection, of any 
 auditory organs. Their sense of sight^ 
 is however somewhat more perfect, 
 though inferior to that of most other an- 
 imals. They are totally destitute of 
 eyelids ; the eyes being covered with 
 the same skin that overspreads the rest 
 of the body. 
 
 The period to which fishes live, is ve- 
 ry little known, though it is generally 
 believed they attain to a considerable 
 age ; some of the least exceed in their 
 age that of a man. The method of dis- 
 covering their ages, is either by examin- 
 ing the transverse coverings of their 
 scales, by means of a microscope ; or by 
 the transverse section of the back bone. 
 Buffon found a carp which by the former 
 method of computation appeared to be 
 a hundred years old, allowing one year 
 
224- Animals* 
 
 for every covering of the scales ; the 
 Skate, and Ray, like other fish \vhich 
 have no scales, have their ages discover- 
 ed, by seperating the joints of the back 
 bone, and then examining the number of 
 rings which the surface exhibited where 
 it vvas joined, allowing one year for each 
 ring. Little can be said in favour of the 
 certainty of either of these methods ; 
 they however, though not infallible cri- 
 terions, enable us to make a near approx- 
 imation to the truth. 
 
 The greatest singularity in fishes, is 
 their amazing fecundity. Some are vi- 
 viparous, and others oviparous ; the lat- 
 ter produce their young, or rather their 
 eggs, in far greater abundance than the 
 former ; but at the same time they are 
 more subject to become the prey of oth- 
 er fish, and even of their own species, 
 not excepting the parent itself which ex- 
 cluded them, while they continue in 
 their egg state ; consequently but very 
 few of these eggs produce live animals, 
 though produced in such considerable 
 numbers. A single Cod will produce 
 above nine million of eggs in one sea- 
 son ; and many other fish have as pro- 
 portionable an increase* 
 
, 
 
 the^ 
 
 Animals. 225 
 
 V. Insects. Insects and animals of 
 e worm kind, seem to form the lowest 
 order among the various tribes of living 
 creatures which inhabit our globe. The 
 distinguishing characters of insects are, 
 that their bodies are covered with 'i 
 of bony substance instead of &1 ; 
 their heads furnished with 
 horns. An insect, may moi ;.- 
 ly be defined a small animal w, 
 blood, (this matter being, white a 
 bones, or cartilages ; furnished 
 trunk, or else a mouth, which d 
 length ways, contrary to the natural or- 
 der ; the eyes destitute of covering ; and 
 lungs opening on the sides of the body. 
 This definition will comprehend the 
 whole class of insects of every descrip- 
 tion. This class of beings is so numerous, 
 and so various, as to exceed the most 
 accurate and unwearied observations. 
 To give the different species of only flies 
 and moths, would be a fruitless attempt ; 
 but to give the history of every species 
 of insect would be utterly impracticable ; 
 so varied are they in their forms, sizes, 
 habitudes, methods of propagation, and 
 manners and duration of life. A gener* 
 T2 
 
226 Animals. 
 
 al division of them, however, according 
 to their most apparent external differ- 
 ences of form, may be attempted. 
 
 The first class of these beings, which 
 present themselves to our observation, 
 appear to be those which are destitute of 
 \vings, and are seen crawling about on 
 every plant and spot of earth. Some of 
 these never acquire wings, but continue 
 in this reptile state during their whole 
 lives. These are all oviparous, except 
 the Flea and the Wood-Louse ; and pro- 
 perly constitute the first division of in- 
 sects. Others which hereafter become 
 winged insects, belonging to the following 
 divisions. 
 
 The second grand division of insects, 
 are those furnished with wings ; but 
 which, when first produced from the 
 egg, appear like reptiles, and have their 
 wings so cased up, as to be quite con- 
 cealed ; but when these cases break, the 
 wings expand, and the animal acquires 
 Its perfect form and beauty. Of this 
 nature are the Dragon Fly, the Grass- 
 hopper, and the Ear- wig. 
 
 The third order of insects, are those 
 of the Moth, and the Butterfly kind. 
 
Animals. 227 
 
 which have all four wings each, covered 
 with a mealy substance of various colours, 
 which easily rubs off; and when examin- 
 ed by the microscope, appears to be ele- 
 gant scales. These insects have a pecu- 
 liar method of propagation ; they are ovi- 
 parous : and when first hatched from the 
 egg, are perfect caterpillars, which often 
 shed their skins ; and after having dives- 
 ted themselves of their skins for the last 
 time, assume new coverings called chrys- 
 alides, in which state they continue till 
 they come forth in their perfect winged 
 forms. 
 
 The fourth division include those wing- 
 ed insects which originate from Worms, 
 and not from Caterpillars like the for- 
 mer, though they undergo similar trans- 
 formations. Some of these are furnished 
 with two, and others with four wings 
 each. The wings of animals of this class 
 differ from those of the Moth and But- 
 terfly kind, in being destitute of those 
 scales with which these are furnished. 
 This class includes all the numerous 
 class of Flies, Gnats, Beetles, &c. 
 
 The fifth and last class of insects, con- 
 tain those which naturalists have termed 
 
228 Anzmak. 
 
 Zoophytes ; and are distinguished by 
 their peculiar mode of propagation, so 
 different from the ordinary course of na- 
 ture. They may be multiplied by dissec- 
 tion ; a'jci some of thorn, though cut in a 
 hundred pieces, will still retain the vital 
 principle in each separate part ; each part 
 shortly becoming a perfect animal ; which 
 ni ;y iv^aiu be increased in the same man- 
 ner. To this class belong the Polypus, 
 the Earth-worm, and all the varieties of 
 the Sea Nettlt. 
 
 Insects are furnished with all the ne- 
 cessary appendages proper to each, for 
 the purposes of defence, of flight, or pro- 
 viding for their own subsistence. The 
 different parts of their bodies, are also 
 constructed with admirable skill. The 
 eye, for instance, is differently formed 
 from that of any other creature : it is ex- 
 ternally rigid, whereby it is not obnoxious 
 to many injuries ; the cornea is divided 
 in every part into lenticular facets, which, 
 viewed by the microscope, appear like a 
 beautiful piece of lattice-work, each open- 
 ing reflecting the rays of light so, that 
 when looked through, the object appears 
 inverted, and thereby supplies the place of 
 
Artimals. 229 
 
 crystalline humour, of which insects are 
 intirely destitute. Larger animals are 
 obliged to turn their eyes towards the ob- 
 ject they wish to behold,but many insects, 
 us flies, have their eyes so constructed as 
 to admit the view of every neighbouring 
 object at once. The numbur of eyes are 
 very different in different insects ; some 
 have only one ; others have two ; spiders 
 have generally eight; and flies have as 
 many as there are perforations in the cor- 
 nea, which are very numerous. Most in- 
 sects are furnished with two antennas, or 
 feelers, which serve to keep their eyes 
 clean. Amphibious insects have their feet 
 formed of flat joints ; and gristles placed 
 on each side of the extremity of the limb, 
 which supply the place of oars, as in the 
 Water- Beetles. Insects formed for leap- 
 ing, as the Cricket and Grasshopper, 
 have strong, brawny, muscular legs; while 
 those who use their claws in perforating 
 the earth, have these members admirably 
 adapted for this purpose. 
 
 Insects and reptiles, though seemingly 
 the most insignificant of animated beings 
 have an important part assigned them to 
 perform in this universe. Though the 
 
230 Animals. 
 
 duration of their life be but as a moment 
 and their strength, when compared with 
 that of the larger animals, as nothing yet 
 their power is often irresistible. The 
 strongest animal which treads the earth 
 is frequently driven to madness by the 
 endless irritation these insignificant beings 
 produce ; the sun himself is deprived of 
 his light by the shading of their wings, 
 and every leaf that can give support to an- 
 imal life is often swept, at once, away by 
 their devouring jaws ; neither has the in- 
 genuity of man, which subdues the stron- 
 gest, and reclaims the most ferocious an- 
 imals, enabled him to devise the means 
 of defending himself from the devastation 
 of these active invaders of his rights. 
 His very existence itself, on many occa- 
 sions, depends upon his speedily with- 
 drawing beyond the sphere of their ac- 
 tive incursions. 
 
 If their power be thus irresistible, their 
 utility is not perhaps less conspicuous on 
 this globe. Man has ever been able, on 
 some occasions, to make them become 
 subservient to his will. The bee collects 
 honey for his use ; the moth, under his 
 influence, affords him silk ; the cantharis 
 
Animals. 231 
 
 an active drug; the cochineal insect the 
 most brilliant of his dyes. Even where 
 they are totally beyond his control they 
 minister indirectly to his wants. Under 
 the form of eggs, maggots, grubs, cater- 
 pillars, aurelice, and flies, they furnish food 
 to innumerable creatures, who augment 
 his comforts in a thousand ways. But it is 
 as the scavengers of this universe that 
 these puny beings become chiefly saluta- 
 ry to man, and all animated nature. With-* 
 out their unceasing aid in this respect, 
 the air would become quickly tainted with 
 the most noxious effluvia, which would 
 soon put an end to animal existence. To 
 obviate this,the beneficentCreator hath de- 
 creed, that a numerous department of this 
 class of beings, while in their reptile state, 
 shall be unceasingly employed in searching 
 for and devouring every thing that has 
 once lived, and is now tending to decay. 
 Under this state of degradation these 
 creatures are doomed to labour for a time 
 with unceasing assiduity : and that no- 
 thing might divert their attention from 
 this important business, even for one 
 moment, the distinctions of sex are with- 
 held from them while in this state ; nor 
 
232 Animals. 
 
 does it seem that these have a single per- 
 ceptive faculty, unless it be that of stri- 
 ving to preserve their existence, and al- 
 lay their insatiable appetite for food.- 
 Having, at length, however, with the 
 most patient assiduity, performed the 
 mental task that was assigned them, they 
 are then called, by the bounty of the Cre- 
 ator, into another and superior state of 
 existence, in which thev are destined to 
 perform a part the most opposite which 
 can be conceived to that they formerly ac- 
 ted. The unsightly grub, after a tempo- 
 rary death, awakens into new life ; and 
 deserting the clod it lately inhabited, and 
 nauseating its former food, sports in the 
 sun-beam, and sips the balmy dew ; nor 
 does the butterfly, now arrayed in the most 
 gorgeous attire, seem to claim the most 
 distant alliance with the ugly caterpillar 
 from whence it sprang. The attraction 
 of sex seems to form the chief business of 
 this period of life ; food is neglected as if 
 unnecessary, and its life is devoted to am- 
 orous dalliance alone. Having soon pro- 
 vided a numerous progency of voracious 
 labourers, it leaves this transitory scene, 
 to make room for those who are destined 
 
Animals* 233 
 
 to supply its important' place in the 
 universe. 
 
 The changes and transformations of in- 
 sects are first from the ovum (egg) into 
 the larva (caterpillar or maggot;) then in- 
 to the pupa (chrysalis) and lastly into the 
 imago (fly.) Pupa is a name derived from, 
 the resemblance of the insect in this state 
 to an infant in swaddling clothes ; and the 
 term is now used in preference tochrysalis. 
 The period of existence in each of these 
 states varies greatly in different species 
 of insects ; but in general they continue 
 much longer in the reptile state than in 
 that of the fly. The species of fly called 
 ichneumon remains in the water as a kind 
 of worm for the space of about two years; 
 in its fly state it seldom continues more 
 than one day. The ephemeron is nearly 
 the same ; and the grub of the cockchaffer 
 remains vmder ground for about two years 
 also ; in its fly state it in general exists 
 only about two months. 
 
2*34 ffuman Frame. 
 
 CHAP. XII. 
 
 Of the Human Frame. 
 
 MAN is placed at the head of the 
 animal creation. Animated and enlight- 
 ened by a ray from the Divinity, he sur- 
 passes in dignity every material being- 
 He was made after all other creatures^ 
 not only as the most perfect, but as the 
 surperintendent and master of all things ; 
 created u to rule over the fish in the sea, 
 and over the fowl of the air, and over 
 cattle, and over the earth, and over every 
 creeping thing*" 
 
 The body of a well-shaped man ought to 
 be square, the muscles ought to be strong- 
 ly marked, the contour of the mejnb 
 boldly delineated, and the features c 
 the face well defined. In women, all the 
 parts are more rounded and softer, the 
 features are more delicate, and the com- 
 plexion brighter. To man belong strength 
 and majesty ; gracefulness and beauty 
 
Hum an Fram e. 235 
 
 the portion of the other sex. Every 
 thing in both sexes points them out as 
 sovereigns of the earth ; even the exter- 
 nal appearance of man declares his su- 
 periority to other living creatures. His 
 head tends towards the heavens, and in 
 his august countenance beams the sacred 
 ray of sapient reason. He alone sheds 
 the tears which arise from emotions of 
 sensibility, unknown to animals ; and he 
 alone expresses the gladness of his soul 
 by laughter. His erect posture and ma- 
 jestic deportment announce his dignity 
 and superiority. He touches the earth 
 only with the extremity of his body ; 
 his arms and hands, formed for nobler 
 ends than the correspondent organs of 
 quadrupeds, execute the purposes oi his 
 mind, and bring every thing within his 
 reach, which can minister to his wants 
 and his pleasures. By his eyes, which 
 reflect the intelligence of thought, and 
 the ardour of sentiment, and which are 
 peculiarly the organs of the soul, are ex- 
 pressed the soft and tender, as well as the 
 violent and tumultuous passions. They 
 are turned, not towards the heavens, but 
 to the horizon, so that he may behold at 
 
236 Human Frame. 
 
 once the sky which illuminates, and the 
 earth which supports him. Their reach 
 extends to the nearest and the most dis- 
 tant objects, and glances from the grains 
 of sand at his feet, to the star which shines 
 over his head at an immeasurable dis- 
 tance. 
 
 'The human body consists of solid and 
 fluid parts, which in general are called 
 the solids and fluids, or humours of the 
 body. The solid parts are bones, cartil- 
 ages, ligaments, muscles, tendons, mem- 
 branes, nerves, arteries, veins, ducts, or 
 fine tubular vessels of various sorts. Of 
 these simple solids the more compound 
 organs of life consist, viz. the brain and 
 cerebellum ; the lungs, the stomach, the 
 liver, the spleen, the pancreas, the kid- 
 neys, the glands, the intestines, together 
 with the organs of sense, viz. the eyes > 
 the ears, the nose, and the tongue. 
 
 The fluid parts of the human body are 
 chyle, blood, saliva or spittle, bile, milk, 
 lympha, the semen, the pancreatic juice ', 
 urine, phlegm, serum, and the aqueous 
 humour of the eyes. 
 
 Anatomists have employed much pains 
 in the study of the material part of man. 
 
Human If ram c, 237 
 
 have assigned to each of the above 
 parts their appropriate use in the econo- 
 my of his frame, but none, perhaps have 
 given so comprehensive and eloquent a 
 description of the structure of man as 
 the late Dr. Hunter. u In order" says 
 this celebrated anatomist, " to acquire 
 a satisfactory general idea of this subject, 
 let us, in imagination, make a man ; in 
 other words, let us construct a fabric fit 
 for the residence of an intelligent soul. 
 This soul is to hold a correspondence 
 with all material beings around her ; and, 
 to that end, she must be supplied with 
 organs fitted to receive the different kinds 
 of impressions which they will make* 
 In fact, therefore, we see that she is pro- 
 vided with the organs of sense, as we 
 call them : the eye is adapted to light ; 
 the ear to sound ; the nose to smell ; the 
 moutJi to taste ; and the skin to touch- 
 Farther, she must be furnished with or- 
 gans of communication between herself 
 in the brain and those organs, to give 
 her information of all the impressions 
 that are made on them ; and she must 
 have organs between herself in the brain 
 .\rA r very -other part of the body fitted 
 U2 
 
 
238 Human Frame. 
 
 to convey her commands and influence 
 over the whole. For these purposes, the 
 nerves are actually given. They are 
 chords which rise from the brain, the 
 immediate residence of the mind, and 
 disperse themselves in branches through 
 all parts of the body. They are intended 
 to be occasional monitors agninst all such 
 impressions as might endanger the well- 
 being of the whole, or of any particular 
 part ; and this vindicates the Creator of 
 all things in having actually subjected us 
 to those many disagreeable and painful 
 sensations which we are exposed to form 
 a thousand accidents in life. Moreover, 
 the mind, in this corporeal system, must 
 be endued with the power of moving 
 from place to place, that she may have 
 intercourse with a variety of objects ; that 
 she may fly from such as are disagreeable, 
 dangerous, or hurtful, and pursue such as 
 are pleasant and useful to her ; and, accor- 
 dingly, she is supplied with muscles and 
 tendons, the instruments of motion, which 
 are found in every part of the fabric where 
 motion is necessary ; but, to give firmness 
 and shape to the fabric ; to keep the softer 
 parts in their proper place ; to give fix- 
 ed points for, and proper direction to, 
 
Human Frame. 239 
 
 its motions, as well as to protect some of 
 the more important and tender organs 
 from external injuries, there must be 
 some firm prop-work interwoven through 
 the whole ; and, in fact, for such pur- 
 poses the bones were given. The prop- 
 work must not be made into one rigid 
 fabric, for that would prevent motion. 
 Therefore, there are a number of bones^. 
 These pieces must all be firmly bound to- 
 gether, to prevent their dislocation ; and 
 this end is perfectly answered by thet/zg*- 
 aments. The extremities of these bony 
 pieces, where they move and rub upon 
 one another, must have smooth and slip- 
 pery surfaces of easy motion. This is 
 most happily provided for by the cartila- 
 ges and mucus of the joints. The inter- 
 stices of all these parts must be filled up 
 with some soft and ductile matter, which 
 shall keep them in their places, unite 
 them, and at the same time allow them 
 to move a little upon one another ; and 
 
 * Dr. Kezll reckons 245 bones in the human 
 body, others make them to be 249, viz. In the 
 skull 14, in the face and throat 46, in the trunk 
 67. in the arms and hands 62, and in the legs and 
 fcet 60. 
 
240 Human Frame. 
 
 these purposes are answered by the eel 
 lar membrane, or adipose substance. 
 There must be an adequate cover, 
 over the whole apparatus, both to give it 
 compactness and to defend it from u 
 thousand injuries ; which, in fact, are v the 
 very purposes of the skin, and other in- 
 teguments. Lastly, the mind being form- 
 ed for society and intercourse with be- 
 ings of her own kind, she must be endu- 
 ed with powers of expressing and com- 
 mu Bleating her thoughts by some sensi- 
 ble marks or signs, easy to herself and 
 capable of great variety ; and accordingly 
 she is provided with the organs and fa- 
 culty of speech, by which she can throw 
 out signs with amazing facility, and van 
 them without end. 
 
 u Thus we have built a body which 
 seems to be pretty complete ; but, as it is 
 the nature of matter to be worked upon 
 and altered so, in a very little time, e. 
 a living creature must 1 'jyed, if 
 
 there is no provision for repairing the in- 
 juries which she will commit upon her- 
 self, and those which she ...Tposed 
 to from without. Therefore,, a treasure 
 of blwd is actually '.e heart 
 
Human Frame. 24 jL 
 
 and vascular system, full of nutritious and 
 .nicies, fluid, and able to pene- 
 trate into the minutest parts of the ani- 
 mal ; impeilfd by the heart, and convey- 
 ed by the arteries, it washes every part, 
 builds up what was broken down, and 
 sweeps away the old useless materials. 
 Hence we see the necessity or advan- 
 tage of the heart and arterial system. - 
 What more than enough there was of the 
 blood to repair the present damages of 
 the machine, must not be lost, but should 
 be returned again to the heart ; and for 
 this purpose the veins are actually provid- 
 ed. These requisites in the animal, ex- 
 plain a priori, the circulation of the 
 blood. The old materials, which are be- 
 come useless, and are swept off by the 
 current of the blood, must be separated 
 and thrown out of the system. Therefore 
 the glands, the organs of secretion, are 
 given for straining whatever is redun- 
 dant, vapid, or noxious, from the mass of 
 blood ; and, when strained, they are 
 thrown out by entunctories, called organs 
 of excretion. But now, as the machine 
 must be constantly wearing, the opera- 
 tions must be carried on without inter- 
 
242 Human Frame. 
 
 mission, and the strainers must be always 
 employed; therefore, there is actually a 
 perpetual circulation of the blood, and 
 the secretions are always going on. Even 
 all this provision, however, would not be 
 -sufficient ; for that store of blood would 
 be soon consumed, and the fabric would 
 break down, if there were not a provision 
 made for fresh supplies. These we ob- 
 serve in fact are profusely scattered round 
 her in the animal and vegetable king- 
 doms ; and she is furnished with hands, 
 the fittest instruments that could have 
 been contrived, for gathering them, and 
 for preparing them in a variety of ways 
 for the mouth. But these supplies, which 
 we call food, must be considerably ch^ng- 
 ed ; they must be converted into blood. 
 Therefore, she is provided with teeth for 
 cutting and bruising the food, and with a 
 stomach for melting it down ; in short, 
 with all the organs subservient to diges- 
 tion. The finer parts of the aliments on- 
 ly can be useful in the constitution : these 
 must be taken up and conveyed into the 
 blood, and the dregs must be thrown off* 
 With this view, the intestinal canal is ac- 
 tually given. It separates the nutritious 
 
Human Frame* 
 
 part, which we call chyle, to be conveyed 
 into the blood by the system of the absor- 
 bent vessels ; and the feces pass down- 
 ward out of the body. Thus we see that, 
 by the very imperfect survey which hu- 
 man reason is able to take of this subjects 
 the animal man, must necessarily be com- 
 plex in his corporeal system, and in its 
 operations; and in taking this general 
 view of what would appear, a priori, to 
 be necessary for adapting an animal to 
 the situations of life, we observe, with 
 great satisfaction, that man is according- 
 ly made of such systems, and for such 
 purposes. He has them all : and he has 
 nothing more, except the organs of respi- 
 ration. Breathing it seemed difficult to 
 account for a priori ; we only know it to 
 be a fact essentially necessary to life. > 
 Notwithstanding this, when we see all 
 the other parts of the body, and their 
 functions so veil accounted for, and so 
 wisely adapted to their several purposes, 
 there would be no doubt that respiration 
 was so likewise ; and, accordingly, the 
 discoveries of Doctor Priestley have late- 
 ly thrown light upon this function also^ 
 " Of all the different systems in the 
 
244 Human Frame. 
 
 human body the use and necessity are not 
 more apparent, than the wisdom and con- 
 trivance which has been exerted in put- 
 ting them all into the most compact and 
 convenient form ; in disposing them so 
 that they shall mutually receive and give 
 helps from one another ; and that all, or 
 many of the parts shall not only answer 
 their principal end and purpose, but ope- 
 rate successfully and usefully in a varie- 
 ty of secondary ways. If we consider 
 the whole animal machine in this light, 
 and compare it with any in which human 
 art has exerted its utmost skill (suppose 
 the best constructed ship that ever was 
 built,) we shall be convinced, beyond the 
 possibility of doubt, that there exists in- 
 telligence and power far surpassing what 
 human art can boast of. Oae superiori- 
 ty in the animal machine is peculiarly- 
 striking. In machines of human contri- 
 vance, or of art, there is no internal pow- 
 er, no principle in the thing itself, by 
 which it can alter and accommodate it- 
 self to any injury that it may suffer, or 
 make up any injury that admits of repair ; 
 but in the natural machine, or animal bo- 
 dy, this is most wonderfully provided fo* 
 
Human Frame* 243 
 
 by the internal powers of the machine 
 itself; many of which are not more cer- 
 tain and obvious in their effects, than they 
 are above all human comprehension as 
 to the manner and means of their opera- 
 tion. Thus, a wound heals up of itself ; 
 a broken bone is made firm by a callus ; 
 a dead part is separated and thrown off; 
 noxious juices are driven out by the 
 emunctories ; a redundancy is removed 
 by some spontaneous bleeding ; a bleed- 
 ing naturally stops of itself; and a great 
 loss of blood, from any cause, is in some 
 measure compensated by a contracting 
 power in the muscular system, which ac- 
 commodates the capacity of the vessel to 
 the quantity contained. The stomach 
 gives information when the supplies have 
 been expended, represents with great ex- 
 actness the quantity and quality of what 
 is wanted in the present state of the ma- 
 chine, and in proportion as she meets with 
 neglect rises in her demand, urges her 
 petition in a louder tone, and with more 
 forcible arguments. For its protection, 
 an animal body resists hea't and cold in 
 a very wonderful manner, and preserves 
 an equal temperature in a burning and i.i* 
 
246 Human Frame. 
 
 a freezing atmosphere. These are pow- 
 ers which mock all human invention or 
 imitation ; they are characteristics of the 
 Divine Architect!" 
 
 Part of the motions of the complicat- 
 ed frame of man, in common with all 
 animated beings, are voluntary, or de- 
 pendent on the mind f and part mvohin- 
 fari/^ or without the mind's direction. 
 
 How the incorporeal existence, which 
 we call mind, can operate on matter, and 
 put it in motion, is to us perfectly incom- 
 prehensible. When the miatomist con- 
 siders the number of muscles that must 
 be put in motion before any animal exer- 
 tion can be effected ; when he views 
 them one by one, and tries to ascertain 
 the precise degree to which every indivi- 
 dual muscle must be constricted, or re- 
 laxed, before the particular motion indi- 
 cated can be effected, he finds himself 
 lost in the labyrinth of calculations in 
 which this involves him ; but when he 
 considers that every one of these muscles 
 must be constricted or relaxed to the pre- 
 cise degree that appertains to each, and 
 no more, and at the same instant of time ; 
 when he recollects, that the smallest jar- 
 
Human Frame. 
 
 ring in this respect in any one of these 
 would throw the whole into inextricable 
 disorder ; when he considers with what 
 promptitude the whole of this is done in 
 an instant by the mere act of his volition, 
 and how in another instant, by a change 
 in that volition, all these muscles are 
 thrown into a different state, and a new 
 set brought into action, and so on conti- 
 nually as long as he pleases, his mind is 
 lost in the immensity of wonder that this 
 excites. But when he farther reflects, 
 that it is not only he himself that is en- 
 dowed with the faculty of calling forth 
 those incomprehensible energies, but that; 
 the most insignificant insect is vested 
 with powers of a similar sort, he is still 
 more confounded., A skilful naturalist 
 has been able to perceive, that in the body 
 of the poorest caterpillar, which, in the 
 common opinion, is one of the most de- 
 graded existences on the globe, there are 
 upwards of two thousand muscles, all of 
 which can be brought into action with as 
 much facility at the will of that insect, 
 and perform their several offices with as 
 much accuracy, promptitude, and preci- 
 sion, as in the most perfect animal ; 
 
248 Human Frame* 
 
 all this is done by that insect with ati 
 equal consciousness of the manner how, 
 as the similar voluntary actions of man 
 are effected. 
 
 Nor are the involuntary motions less 
 mysterious and wonderful. The sto- 
 mach, the intestines, and all the functions 
 necessary to life, wait not to be called in- 
 to action by any volition of ours. The 
 heart, placed near the centre of the sys- 
 tem, performs its task as well ..when we 
 are asleep, as when we are awake, by night 
 as by day, and like an unwearied and 
 iaithful labourer, with muscular exertions 
 distributes the vital stream through our 
 complicated frame, 'till their wearied 
 functions cease, and the tenement of clay 
 is inhabited no more. How admirably 
 It is calculated to keep up this continued 
 circulation throughout the system may 
 be understood by the following computa- 
 tion by Dr. Keill: u Each ventricle will 
 at least contain one ounce of blood. The 
 hearts contracts four thousand times in 
 one hour ; from which it follows, that 
 there passes through the heart, every 
 hour, four thousand ounces, or three 
 hundred and fifty pounds of blood, Now 
 
Human Frame. 249 
 
 the whole mass of bloed is said to be 
 about twenty-five pounds, so that a quan- 
 tity of blood equal to the whole mass of 
 blood passes through the heart fourteen 
 times in one hour ; which is about once 
 every four minutes-" Consider what an 
 affair this is when w T e come to very large 
 animals. The aorta of a whale is larger 
 in the bore than the main-pipe of the 
 water-works at London-Bridge ; and the 
 wat,er roaring in its passage through that 
 pipe, is inferior in impetus and velocity 
 to the blood gushing from the whale's 
 heart. Hear Dr. Hunter's account of the 
 dissection of a whale. u the aorta mea- 
 sured a foot diameter. Ten or fifteen 
 gallons of blood is thrown out of the 
 heart at a stroke, with an immense velo- 
 city, through a tube of a foot diameter. 
 The whole idea fills the mind with won- 
 der." It is thus, O great Author of all 
 Things ! we discover Thee in thy works* 
 
 OF THE FIVE SENSES. 
 
 Of Seeing-. The organ of seeing is 
 the Eye. It is a curious and most won- 
 derful piece of nature's work> admirably 
 rontrived with various coats^ muscles. 
 
Human Frame. 
 
 vessels, and humours of three several 
 >, for the purpose of vision. The 
 first humour of the eye is called the aque- 
 ous humour, being in all respects like 
 water, hut of a spirituous nature ; for it 
 will not freeze in the greatest cold. The 
 second is called the crystalline humour^ 
 being transparent, and more solid than, 
 cither of the other ; its figure resembles 
 an optic lens, convex on both sides, and 
 its use in the eye is the same. Behind 
 this lies the vitreous or glassy humour ; 
 it is very much like the white of an egg ; 
 it is in greater abundance than either 
 of the other ; it gives the eye its spheri- 
 cal form ; and is thicker than the aque- 
 ous, but thinner than the crystalline hu- 
 mour. Next this humour, on the bot- 
 tom of the eye, is spread a fine curious 
 rnembrane, called the retina, through 
 which are expanded the medullary fibres 
 of the cpi'ic nerve, which come from the 
 brain. Now the rays of light, which 
 come from all parts of any object, falling 
 upon the aqueous humour of the eye, are 
 through it refracted to the crystalline hu- 
 humour, by which, as a double convex 
 lens (kept always at a proper distance by 
 
Human Frame, 25 i 
 
 the glassy humour) they are all converg- 
 ed and united on the retina ; -the impres- 
 sion thereof being communicated to the 
 common sensory of the brain by the optic 
 nerves, doth there present to the mind 
 the species and image of the object. 
 
 That, which immediately affects the 
 sight, and produces in us that sensation, 
 which \ve call seeing, is light. 
 
 Light may be considered either, first, 
 as it radiates from luminous bodies di- 
 rectly to our eyes ; and thus we see lu- 
 minous bodies themselves, as the sun, or 
 a flame, &c. or, secondly, as it is reflect- 
 ed from other bodies ; and thus we see 
 a man, or a picture by the rays of light 
 reflected from them to our eyes. 
 
 Bodies, in respect of light, may be di- 
 vided into three sorts ; first, those that 
 emit rays of light, as the sun and fixed 
 stars ; secondly, those that transmit the 
 rays of light, as the air ; thirdly, those 
 that reflect the rays of light, as iron, 
 earth, &c. the first are called luminous ; 
 the second pellucid ; arid the third opaque. 
 
 Opaque bodies are of two sorts, specu- 
 lar, or not specular. Specular bodies, or 
 mirrors ? are such opaque bodies whose 
 
:252 Human Frame* 
 
 surfaces are polished ; whereby they, re- 
 flecting the rays in the same order as they 
 come from other bodies, shew us their 
 images. 
 
 The rays that are reflected from opaque 
 bodies always bring with them to the eye 
 the idea of colour; and this colour is 
 nothing else in the bodies, but a disposi- 
 tion to reflect to the eye more copiously 
 one sort of rays than another. For par- 
 ticular rays are originally endowed with 
 particular colours ; some are red, others 
 blue, others yellow, and others green, &c. 
 
 Every ray of light, as it comes from 
 the sun, seems a bundle of all these seve- 
 ral sorts of rays ; and as some of them 
 are more refrangible than others ; that 
 is, are more turned out of their course, 
 in passing from one medium to another, 
 it follows, that after such refraction they 
 will be separated, and their distinct co- 
 lour observed. Of these, the most re- 
 frangible are violet, and the least red ; 
 and the intermediate ones, in order, are 
 indigo, blue, green, yellow, and orange. 
 This separation is very entertaining, and 
 will be observed with pleasure in hold- 
 ing a prism in the beams of the sun. 
 
Human Frame. 253 
 
 As all these rays differ in refrangibili- 
 ty 7 60 they do in reftexibilrty, that is, in 
 the property of being more easily reflect- 
 ed from certain bodies, than from others ; 
 and hence arise, as hath been said, ail 
 the colours of bodies, which are in a 
 manner infinite, as an infinite number of 
 compositions, and proportions of the 
 original colours may be imagined. 
 
 The whiteness of the sun's light is 
 compounded of all the original colours 
 mixed in a due proportion. 
 
 Whiteness, in bodies, is but a disposi- 
 tion to reflect all colours of light nearly 
 in the proportion they are mixed in the 
 original rays ; as, on the contrary, black- 
 ness, is only a disposition to absorb or 
 stifle, without reflection, most of the rays 
 f every sort that fall on the bodies. 
 
 Besides colour, we are supposed to 
 see figure ; but in truth, that which we 
 perceive when we see figure, as perceiv- 
 able by sight, is nothing but the termina- 
 tion of colour. 
 
 Of hearing, Next to seeing, hearing 
 is the most extensive of our senses. The 
 Ear is the organ of hearing. 
 
 Sounds are brought to the ear from so 
 
254 Human Frame. 
 
 norous bodies by means of the ail- ; and 
 the external part of the ear is so contriv- 
 ed, by its ridges and hollows, that sounds, 
 being gathered into it as into a tunnel, 
 are thereby directed to the meatus audi- 
 torious, through -which they pass and 
 strike upon a thin transparent membrane 
 of an oval figure, set a little obliquely 
 across the passage of the ear ; behind 
 this membrane there is a pretty large ca- 
 vity, which, with the said membrane, 
 from its resemblance, is called the tympa- 
 num, or drum of the ear. In this cavity 
 are four small bones, which from their 
 form are called malleolus, or the hammer ; 
 the incus, or the anvil ; the shapes* or 
 stirrup ; and the os orbicculure, or circu- 
 lar bone. Within the tympanum there 
 are several other cavities, as the vestibu* 
 him, the labyrinth, and the cochlea ; these 
 Internal cavities are always full of air ; 
 wherefore the sounds in the external air 
 striking on the drum, move the four lit- 
 tle bones in the tympanum, and these in 
 like manner move the internal air, which 
 maketh an impression on the fine bran- 
 ches of the auditory nerve spread through 
 the vestibulum, the winding tubes of the 
 
Human Frame, 23* 
 
 labyrinth, and cochlea ; and thus all re- 
 fractions and modulations of the exter- 
 ternal air become perceptible, and conse- 
 quently all the different sounds they con- 
 vey become audible, and intelligible to 
 the mind, by the communication of these 
 nerves with the brain, or common sensory* 
 
 That which is conveyed into the brain 
 by the ear, is called sound, though in 
 truth, till it come to reach and affect the 
 perceptive part, it be nothing but motion* 
 
 The motion which produces in us the 
 perception of sound, is a vibration of the 
 air, caused by an exceeding short, but 
 quick, tremulous motion of the body from 
 which it is propagated ;*' and therefore we 
 consider and denominate them as bodies 
 sounding. 
 
 That sound is the effect of such a 
 short, brisk, vibrating motion of bodies 
 from which it is propagated, may be 
 known from what is observed and felt in 
 the strings of instruments, and the tremb- 
 ling of bells, as long as we perceive any 
 sound come from them ; for as soon as 
 that vibration is stopped, or ceases in 
 them, the perception ceases also. 
 
 Of Smelling. Smelling is another 
 
256 Human Frame* 
 
 sense. The organ of smelling is trft Nose 
 The cavity of the nose is divided into 
 two parts, we call the nostrils, by a parti- 
 tion, of which the upper part is bony, 
 and the lower cartilaginous. The upper 
 part of the cavity is covered with a thick 
 glandulous membrane, above which the 
 olfactory nerve is finely branched out anc 1 
 spread over the membrane of the spon- 
 gy bones of the nose, and other sinous 
 cavities of the nostrils. Whence the ex- 
 halations of odours entering the nostrils 
 make their impressions on the fibres of 
 the nerves, which by their communica- 
 tion with the brain, excite in the mine" 
 the smell or sensation of odours of eve- 
 ry kind. 
 
 Smelling bodies seem perpetually td 
 send forth effluvia or steams, without 
 sensibly wasting at all. Thus a grain of 
 musk will send forth odoriferous parti- 
 cles for scores of years together, without 
 its being spent ; whereby one would con- 
 clude that these particles are very small ; 
 and yet it is plain, that they are much 
 grosser than the rays of light, which have 
 a free passage through glass ; and gros- 
 ser also than the magnetic effluvia, which 
 
Human Frame. 25? 
 
 pass freely through ail bodies, when those 
 that produce smell will not pass ihe thin 
 membranes of a bladder, and many of 
 them scarce ordinary white paper. 
 
 There is a great variety of smelts, 
 though we have but a few names for 
 them; sweet, stinking, sour, rank, and 
 musty, are almost all the denominations 
 we have for odours j though the smell of 
 a violet, and of musk, both called sweet > 
 are as distinct as any two smells whatso- 
 ever. 
 
 Of Taste. Taste is the next sense to 
 be considered* The organ of -Taste is 
 the Tongue. 
 
 The tongue is covered with two mem- 
 branes ; the external is thick and rugged, 
 especially in beasts ; the internal me<m- 
 brane is thin and soft ; upon it appear se- 
 ver d\ papillae or small risings, like the tops 
 of the small horns of snails ; these papil- 
 lae are made of the extremities of the 
 nerves of the tongue, and piercing the ex- 
 ternal membrane, are constantly affected 
 by those qualities in bodies, which have 
 their tastes excited in the mind by means 
 of these nervous papillae ; and thus are 
 these papillae the immediate organ of 
 tasting. Y 
 
Human Frames, 
 
 It may be observed of tastes, tha* 
 though there be a great variety of them, 
 yet, as in smells, they have only some few 
 general names, as sweet, bitter, sour, 
 harsh, rank, and some few others. 
 
 Of Touch. The fifth and last of our 
 senses is Touch ; a sense spread over the 
 whole body, though it be most eminently 
 placed in the ends of the fingers. 
 
 By this sense the tangible qualities of 
 bodies are discerned ; as hard, smooth, 
 rough, clry r wet, clammy, and the like. 
 
 But the most considerable of the quali- 
 ties that are perceived by this sense are 
 Jieat and cold. 
 
 The due temperament of those two 
 opposite qualities is the great instrument 
 of nature, that she makes use of, in most, 
 if not all her productions. 
 
 Heat is considered by some as merely 
 the consequence of a very brisk agitation 
 of the insensible parts of the object 
 which produces in us that sensation, but 
 it is most generally supposed that these 
 effects depend on a certain matter called 
 caloric, or the matter of heat. 
 
 Bodies are denominated hot and cold 
 in proportion to the present temperament 
 
Human Frame. 
 
 of that part of our body to which they are 
 applied ; so that feels hot to one which, 
 seems cold to another ; nay, the same bo- 
 dy felt by the two hands of the same man 9 
 may at the same time appear hot to .the 
 one. and cold to the other. 
 
26O Human Understanding* 
 
 CHAP. XIII. 
 
 Of the Human Understanding. 
 
 THE understanding of Man is what 
 particularly exalts him above the brute 
 creation. Though some of the most sa- 
 gacious of animals appear, in regard to 
 intellect, in certain points of view, to 
 approximate to the lowest of the human 
 species, yet there can be no doubt that 
 man is much farther exalted above them 
 all, than any one of these excels the 
 next below it ; for though many of the 
 higher orders possess a kind of memo- 
 ry, and the faculty of reasoning in a cer- 
 tain degree ; though " the ox knoweth 
 his owner, and the ass his master's crib," 
 yet, unless it be in recollecting their de- 
 pendence on others for food, and a few 
 circumstances of a similar nature, ten- 
 ding chiefly to the preservation of exist- 
 
Human Understanding. 261 
 
 ence, the intellectual powers of even the 
 highest is extremely circumscribed. 
 The dog is a favoured, and a very saga- 
 cious domestic animal: he feels the be- 
 nign influence of the parlour fire, and 
 enjoys it as much as any of the human 
 gpecies ; but he never can be made senr- 
 sible of the uses to which heat may be 
 applied in changing the nature of bodies 
 which are subjected to its power ; he 
 never can be made to conceive how a 
 piece of coal, or a billet of wood, can 
 augment the heat, and continue to sup- 
 port it ; and thus he cannot spontaneous- 
 ly feed the fire when occasion shall re- 
 quire it ; a degree of reasoning which a 
 child acquires almost before it can walk, 
 and which even an idiot knows. In 
 like manner the elephant, the most saga- 
 cious of the brute creation, delights in 
 the sugar-cane, and gives evident indica- 
 tions that this is a food which he relish- 
 es in the highest degree, and when he 
 once discovers where it is to be found, 
 will expose himself to any danger to ob- 
 tain it ; but .no elephant hath ever yet 
 been able to discover that if the joints, 
 of these plants be buried to a certain 
 Y2 
 
262 Human Understanding. 
 
 depth in newly turned up earth, it 
 there revive, and send up shoots, which 
 in due* time w ; li fiord abundance of his 
 favov.vjt;- food. This kind of reasoning, 
 thouga it be the most obvious to all man- 
 kind, is far beyond the limited faculties 
 of the brute creation. It is man alone 
 who, by comparing facts that fall under 
 his cognizance, and reasoning upon them, 
 has been enabled to subject all nature to 
 his sv/ny. Nor is it alone from the facts 
 that fall under his own observation that 
 he derives this kind of knowledge ; by 
 the gift of language he has it communi- 
 cated to him by others, or transmitted to 
 him from the experience of former ages. 
 "While then the different species of ani- 
 mals universally have the same powers 
 and propensities at this moment that they 
 had at the earliest period they were 
 known, the human species are advancing 
 from age to age, and the power of man, 
 of course, gradually extending as his 
 knowledge increases. 
 
 Thus is man by the faculties of his 
 mind pre-eminently distinguished from 
 all other animals ; hut as he comes into 
 the world without any idea or principle^ 
 
Human Understanding. 263 
 
 either speculative or practical, it is only 
 by the cultivation of his intellect that he 
 can fairly claim this superiority ; there- 
 fore leaving this part of our subject, we 
 will proceed to the consideration of the 
 distinct operations of the human under- 
 standing ; define its powers, and show 
 the method by which it acquires the 
 stock of its ideas, and accumulates gen- 
 eral knowledge. 
 
 The primary faculty of the mind is 
 Perception. Perception consists in the 
 attention of the understanding to the ob- 
 jects acting upon it, whereby it becomes 
 sensible of the impressions they make ; 
 and the notices of these impressions, as 
 they exist in the mind, are distinguished 
 by the name of Ideas. 
 
 Sensation and Refection are the two 
 fountains or sources from which the un- 
 derstanding is supplied with all its ideas, 
 or materials of thinking. 
 
 Sensation is the source of our origin- 
 al ideas, and comprehends the notices 
 conveyed into the mind by impulses or 
 impressions made upon the organs of 
 sense. Such are the perceptions of col- 
 ours, sounds, tastes, &c. We derive all 
 Y3 
 
254 Human Understanding. 
 
 these ideas, numerous as they are, solely 
 from external objects. 
 
 Refection is the mind's perception of 
 its own faculties and operations. Thus 
 by reflection we acquire the ideas of 
 thinking, doubting, believing, &c. which 
 are the different intellectual operations 
 represented to us by our consciousness. 
 
 A proper consideration of these two 
 sources of our thoughts will give us a clear 
 and distinct view of the nature of the mind 
 and the first steps it takes in the path of 
 knowledge. The mind thus stored with 
 its original notices of things, has a power 
 of combining,moclifying,and placing them 
 in an infinite variety of lights, by which 
 means it is enabled to multiply the objects 
 of its perception, and finds itself possessed 
 of an inexhaustible stock of materials for 
 refit ction and reasoning. And it is to be 
 particularly observed, that amongour nu- 
 merous discoveries, and the infinite vari- 
 ety of our conceptions, we are unable to 
 find one original idea, which is not deri- 
 ved from sensation or reflection ; or one 
 complex idea, which is not composed of 
 these original ones. 
 
 The ideas with which the mind is thus 
 
Human Understanding. 26J 
 
 furnished are either Simple or Complex* 
 
 Simple Ideas are such as exist in the mind 
 under one uniform appearance, and can- 
 not be divided into two or more ideas > 
 for example, a colour, a sound. 
 
 Complex Ideas consist of several simple 
 Ideas united in the same representation, 
 appearance or perception; and they either 
 come into the mind thus united from the 
 operation of things without us,as the idea, 
 solidity and figure, is caused by the same 
 ball ; therefore in the complex idea of the 
 ball we conceive such ideas as co-existent 
 and concomitant ; or else when such sim- 
 ple ideas are united by the mind, as in the 
 idea of law, obligation, ^c. 
 
 In the production of Complex Ideas 
 which are formed at the pleasure of the 
 mind, it exerts three voluntary acts, viz* 
 Co mposition,Abstr action, and Comparison* 
 
 Composition is joining together two or 
 more Simple Ideas, and considering them 
 as one picture or representation. By 
 composition we have the ideas of num- 
 ber, extension, &c. 
 
 Abstraction is separating from a par- 
 ticular idea those circumstances which 
 render it the representative of a single 
 
266 Human Understanding* 
 
 determinate object, and thereby making 
 it to denote a whole rank or class of things. 
 Hence we acquire Universal Ideas, such 
 as whiteness, beauty, melody, &c. 
 
 Comparison is bringing two or more 
 ideas into the view of the mind, and ex- 
 amining their mutual correspondencies* 
 By comparison we gain our ideas of Re- 
 lations, which are proportional, as equal, 
 more, less, Sec. or natural, as father, 
 mother, &c. or civil, as king and people,, 
 general and army, &c. 
 
 This division of our ideas, as it seems 
 to be the most natural, and truly to rep- 
 resent the manner in which they are in- 
 troduced into the mind, will be found to 
 include them in all their varieties. 
 
 We know that our thoughts, although 
 so numerous and manifold, are all con- 
 tained within our own breasts, and are in- 
 visible. But as men were not created to 
 live solitarily, or independently of each 
 other, we are provided with organs pro- 
 per for framing articulate sounds, and a 
 capacity of using those sounds as signs of 
 internal conceptions. From hence are 
 derived words and language. For any 
 sound being once determined upon to 
 
Human Understanding. 26JT 
 
 stand as the sign of an idea, custom by 
 degrees establishes such a connexion be- 
 tween them, that the appearance of the 
 idea in the understanding always brings 
 to our remembrance the name by which 
 it is expressed ; and in like manner the 
 hearing of the name never fails to excite 
 the idea which it is intended to denote. 
 This connexion between words and ideas, 
 however, is perfectly arbitrary, and 
 dependent on custom. 
 
 By language we are enabled to define 
 our ideas. Definition is " the showing 
 the meaning of one word by several oth- 
 er not synonymous terms." And here it 
 may be observed, that Simple Ideas can- 
 not be defined, since definition is resol- 
 ving the thing to be defined into its most 
 simple ideas ; but Complex Ideas may be 
 defined, because they may be resolved in- 
 to their simple ideas. Definition furnish- 
 es us with the fittest means of communica- 
 ting our thoughts ; for if we were unable 
 to impart our Complex Ideas to each oth- 
 er by the aid of definition, it would in ma- 
 ny cases be impossible to make them 
 known. This is evident in those ideas 
 which are solely the offspring of the min(l 
 
268 Human Understanding*. 
 
 For as they exist only in the understand- 
 ing, and have no real objects in nature, in 
 conformity to which they are framed, if 
 \ve could not communicate them to others 
 by description, they must be confined to 
 the narrow limits of a single mind. All 
 the beautiful ideas formed by the fancy of 
 a Shakspeare or a Milton, without the 
 faculty of displaying them by words, 
 would never have extended their influence 
 beyond their own breasts. 
 
 All language may be resolved into 
 Nouns and Verbs , with their respective 
 Abbreviations. 
 
 Nouns express names of things : they 
 are divided into Substantives, which are 
 the principal things spoken of ; and Ad- 
 jectives, which denote qualities, or cir- 
 cumstances belonging to them. 
 
 Verbs express modes of existence. 
 They are of three kinds, such as denote 
 simple existence ; for example, to be ; 
 such as express existence in an active 
 state, for example, to eat : and such as 
 express existence in a passive state ; as, 
 to be eaten. 
 
 Words which are usually represented as 
 indeclinable particles having no deter- 
 
Human Understanding. 269 
 
 minate signification of their own, are Ab- 
 breviations of Nouns or Verbs, invented 
 for the greater expedition of commuica- 
 ting our thoughts. Thus If signifies 
 give, and signifies add, being impera- 
 tives of corresponding verbs. See this 
 theory of language stated and evinced in 
 Mr.HorneTooke's Diversions of Purley. 
 
 Having thus considered our ideas, 
 which are the materials of our knowledge, 
 and our language, which is the manner 
 of our conveying them to others ; the 
 last thing is to consider how our ideas 
 are put together, and compared one with 
 the other. 
 
 And herein, First, of Knowledge. 
 
 Knowledge, which is the highest de- 
 gree of the speculative faculties, consists 
 in the perception of the connexion and 
 agreement, or disagreement and repug- 
 nancy of our ideas. 
 
 This perception is either immediate or 
 mediate. Immediate perception of the 
 agreement or disagreement of two ideas, 
 is when, by comparing them together in 
 our minds, we see, or, as it were, we 
 behold their agreement or disagreement. 
 This therefore is called Intuitive Know- 
 
27O Human Understanding, 
 
 ledge. Thus we see that red is not green - 9 
 that the whole is bigger than a part ; that 
 two and two are equal to four. 
 
 The truth of these and the like propo- 
 sitions we know by bare simple intuition 
 of the ideas themselves, without any more 
 ado ; and such propositions are called 
 self-evident. 
 
 The mediate perception of the agree-, 
 ment or disagreement of two ideas, is, 
 when by the intervention of one or more 
 other ideas, their agreement or disagree- 
 ment is shewn. This is called Demon- 
 stration or Rational Knowledge. For 
 instance, the inequality of the breadth 
 of two windows, or two rivers, or any 
 two bodies that cannot be put together, 
 may be known by the intervention of 
 the same measure applied to them both ; 
 and so it is in our general ideas, whose 
 agreement or disagreement may be often 
 shewn by the intervention of some other 
 ideas, so as to produce demonstrative 
 knowledge, where the ideas in question 
 cannot be brought together, and immedi- 
 ately compared, so as to produce intui- 
 tive knowledge. 
 
 Secondly, Of Judgment. 
 
Human Understanding. 
 
 judgment is that faculty which is giv- 
 en man to supply the want of clear and 
 certain knowledge, where that cannot be 
 had. It consists in putting ideas togeth- 
 er, or seperating them from one another 
 in the mind, when their certain agree- 
 ment or disagreement is not perceived, 
 but presumed to be so ; which is, as the 
 word imports, taken to be so before it 
 certainly appears. 
 
 Hence the understanding doth not on- 
 ly know certain truth, but also judges of 
 probability* Probability is always con- 
 versant about propositions whereof we 
 have no certainty, as in knowledge, but 
 only some inducements to receive them 
 as true ; such as their conformity to our 
 own knowledge, observation and experi- 
 ence ; and the entertainment the mind 
 gives this sort of propositions is called 
 assent, opinion or belief. 
 
 Of probability there are various de- 
 grees, from a moral certainty to the 
 slightest degree of evidence ; and the 
 degrees of assent are proportionably va- 
 rious, from the least deviation from the 
 equilibrium to the lowest degree upon 
 the scale of evidence, and even to amor- 
 al impossibility* 
 
272 Human Understanding, 
 
 Lastly, Of Reason. 
 
 Reason is the pre-eminent faculty of 
 the human mind, and is necessary and 
 assisting to all our other intellectual fa- 
 culties. By it we enlarge our know- 
 ledge and regulate our assent ; for it hath 
 to do both in knowledge and opinion, 
 and is the faculty which finds out the 
 means, and rightly applies them, to dis- 
 cover certainty in the one, and probabil- 
 ity in the other. It is Reason which 
 perceives the necessary and indubitable 
 connexion of all the ideas and proofs one 
 to another, in each step of any demon- 
 stration that produces knowledge ; it like- 
 wise perceives the probable connexion 
 of all the ideas or proofs one to another, 
 in every step of a discourse to which it 
 will think assent due ; and where the 
 mind does not perceive this probable 
 connexion or no ; there men's opinions 
 are not the product of Judgment, or the 
 consequence of Reason, but the effects 
 of chance, and of a mind floating at all 
 adventures, without choice, and without 
 direction* 
 
 FINIS.