PRACTICAL MASONRY:
OR
A THEORETICAL AND OPERATIVE TREATISE OE BUILDING ;
CONTAINING A
SCIENTIFIC ACCOUNT OF STONES, CLAYS, BRICKS, MORTARS, CEMENTS, FIRE-
PLACES, FURNACES, &c.; A DESCRIPTION OF THEIR COMPONENT PARTS,
WITH THE MANNER OF PREPARING AND USING THEM ;
AND
THE FUNDAMENTAL RULES IN GEOMETRY,
ON
M A S O N R Y A N p . S X 0 N E - C XI T T I; N G ; ; • : • .
WITH
THEIR APPLICATION TO PRACTICE A C
ILLUSTRATED WITH FORTY-FOUR COPPERPLATE ENGRAVINGS.
By EDWARD SHAW, Architect,
AUTHOR OP “civil ARCHITECTURE,** “RURAL ARCHITECTURE,** ETC.
\J
BOSTON:
PUBLISHED BY BENJAMIN B. MUSSEY.
1846 .
Entered according to Act of Congress, in the year 1845, by
EDWARD SHAW,
in the Clerk’s Office of the District Court for the District of Massachusetts.
CAMBRIDGE:
METCALF AND COMPANY
PHINTERS TO THE CNIVERSITT.
PREFACE.
In preparing this work for the public, it has been the design of the
Compiler to avoid prolixity, by the rejection of such things as are already
known to the mechanic, and to furnish him with a knowledge of the prin-
ciples and facts on which he might be supposed to require information.
Most works on this subject set out with a description of all the minutiae
of the art of building ; and though they may, perhaps, exhibit something
that will be useful to the apprentice, yet they contain much that is of no
importance to the practical mechanic ; while the price is so much enhanced,
that few can well afford to possess them.
As permanency in building seems, at the present day, to be an object
more desirable than formerly, it has been thought that a brief account of the
nature and qualities of building materials, with a short exposition of their
component parts, would not be misplaced in a treatise of this kind. The
Compiler flatters himself, that he has, on this head, furnished some informa-
tion, that will be serviceable not only to the operator but to the proprietor ;
neither of whom can, with safety, remain unacquainted with the quality of
the materials employed.
The best writers on the various subjects treated of in this work have
been consulted, and such use made of their labors, by abridging, altering,
abstracting, and condensing, as seemed advisable to the Compiler, while he
has added much that has been the result of many years of practical ex-
perience and personal observation. The latest improvements in building have
been noticed and brought to the attention of the reader.
In short, brevity with perspicuity, and utility with cheapness, have been
aimed at. How far they have been attained is submitted to the decision of
an enlightened and indulgent public.
/ S. o /
V
I ■
I
Digitized by the Internet Archive
in 2015
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CONTENTS
CHAPTER I.
SECTION PAGE
I. Marble ........ 1
II. The Polishing of Marble . . . . . . .7
III. Artificial Marble ....... 9
IV. The Coloring of Marble . . ..... 9
V. Granite ....... 12
VI. Sienite . . ■ • • • • • .21
VII. Greenstone ........ 23
VIII. Sandstone, or Freestone . . . . . . .23
IX. Gneiss ........ 25
X. Mica-slate . . . • • • • .26
XI. Slate ........ 26
XII. Soapstone, or Steatite . . . • . . .29
XIII. Gypsum . 30
XIV. Puzzolana . . . • • • • .31
XV. Tras, or Terras ....... 32
XVI. Quarrying . . . • • • • .32
Table showing the Weight of Granite Stone .... 37
Mean Weight of a Cubic Foot of Stone .... 38
Table of Cylindrical Measures ..... 38
Table for the Computation of the Weight of Wrought Iron . . 39
Rules for measuring Hammered Granite Stone . . .40
CHAPTER II.
I. Clay . . . . . . . , .43
II. Brick-making ....... 44
III. Faced or Pressed Bricks . . . . . .47
• 4
VI
CONTENTS.
SECTION
PAGE
PI.ATE
IV.
Brick Masonry ......
48
V.
Tiles . . ......
50
VI.
Compact Limestone .....
50
VII.
The Burning of Lime ......
51
VIII.
Of Mortars and Cements .....
52
IX.
Common Mortar and Cement .....
62
X.
Observations on Mortar .....
63
XI.
Making of Mortar ......
63
XII.
Monsieur Loriat’s Mortar .....
64
XIII.
Dr. Higgins on Mortar ......
65
XIV.
Observations on Antique Mortar ....
67
XV.
Stucco .......
69
XVI.
Adam’s Oil Cement, or Stucco ....
69
XVII.
Scagliola .......
71
XVIII.
Manner of forming Columns or Pilasters in Scagliola
71
XIX.
Modelling for Stucco or Plaster of Paris
72
XX.
Moulding of Ornaments .....
73
XXI.
Moulding in Plaster ......
74
XXII.
Fixing Ornaments ......
74
XXIII.
Stucco Cornices ......
75
XXIV.
Circular and Elliptical Cornices or Mouldings
76
XXV.
External Compositions ......
76
CHAPTER III.
PRACTICAL GEOMETRY, ADAPTED TO MASONRY AND STONE-CUTTING.
I.
On the Position of Lines and Points
82
1
II.
On the Species, Nature, and Construction of Curve Lines
86
2
III.
Of the Position of Lines and Planes, and the Properties arising
from their Intersections .....
89
1
IV.
Of the Right Sections of Arches or Vaults
91
3
I.
CHAPTER IV.
On the Nature and Construction of Trehedrals
93
2, 3
II.
On the Projection of a Straight Line bent upon a Cylindric Sur-
face, and the Method of drawing a Tangent to such a Projection
97
3.
SECTION
III.
Application of Geometry to Planes and Elevations, and also to the
PAGE
PLATE
Construction of Arches and Vaults ....
98
4
IV.
On the Developments of the Surfaces of Solids
105
4
V.
Construction of the Moulds for Horizontal Cylindretic Vaults,
either terminating Rightly or Obliquely, upon Plane or Cylin-
drical Walls, with the Joints of the Courses either in the Di-
rection of the Vault, perpendicular to the Faces, or in Spiral
Courses ....
106
VI.
On Oblique Arches .....
109
5-8, 10
VII.
A Circular Arch in a Circular Wall
127
9
VIII.
A Conic Arch in a Cylindric Wall ....
128
9, 12
IX.
Construction of the Moulds for Spherical Niches, both with Ra-
diating and Horizontal Joints, in Straight Walls .
132
X.
Examples of Niches with Radiating Joints in Straight Walls
133
13, 14
XI.
Examples of Niches in Straight Walls, with Horizontal Courses
135
14, 15
XII.
Construction of the Moulds, and Formation of the Stones, for
Domes upon Circular Planes ....
137
17, 18
XIII.
The Manner of finding the Sections of Raking Mouldings
149
19
XIV.
Construction of a Lintel, or an Architrave, in three or more Parts,
over an Opening, and the Steps of a Stair over an Area
150
15,19,25
XV.
Construction of the Stones for Gothic Vaults, in Rectangular
Compartments upon the Plan ....
152 20,21,26
CHAPTER V.
I.
Ancient Walls ......
157
22
II.
Construction of Brick Arches .....
159
23
III.
Bricklaying ......
159
23
IV.
Foundations .......
164
23
V.
Walls, &c. ......
165
23
VI.
The Construction of Chimneys ....
166
27
VII.
Fire-places ......
168
27, 28
VIII.
Warming by Steam and Hot Water ....
169
29-35
IX.
On the Construction of Ovens, Boilers, Fire-places, and of the
Setting of Copper .....
177
37, 38
CONTENTS,
viii
CHAPTER VI.
ORDERS OF ARCHITECTURE.
SECTION
1. Grecian Doric
.
.
.
.
PAGE
. 181
II. Grecian Ionic
.
.
.
181
III. Grecian Corinthian
. 182
Glossary of Architectural Terms .... 183
PLATE
39, 40
41, 42
43, 44
PRACTICAL MASONRY.
CHAPTER I.
SECTION I. — Marble.
The class of stones denominated Calcareous is exceedingly numerous and
abundant in nature. Of these, marble is the most important. It is a granular
carbonate of lime, or a compact limestone, varying in color, texture, and hard-
ness. Its structure is both foliated and granular. The grains are of various
sizes, from coarse to very fine, sometimes, indeed, so fine that the mass appears
almost compact. When these grains are white, and of a moderate size, this
mineral strongly resembles white sugar in solid masses.
Its fracture is foliated ; but the faces of the laminae, which vary in extent,
according to the size of the grains, are sometimes distinguishable only by their
glimmering lustre. When the structure is very finely granular, the fracture often
becomes a little splintery.
Both its hardness and the cohesion of its grains are somewhat variable. In
some cases, its hardness undoubtedly depends on the presence of siliceous
particles ; indeed, it sometimes gives a few sparks with steel. Its specific gravity
usually lies between 2.71 and 2.84, water being 1. That is, water as a
standard being taken as a unit, the specific gravity of marble is from 2iVo units
to 2tVo units when compared to water, or about 2f times greater.
It is more or less translucent, but, in the dark colored varieties, at the edges
only. Its color is most commonly white or gray, often snow-white, and some-
times grayish -black. It also presents certain shades of blue, green, red, or
yellow. Most frequently the colors are uniform, but sometimes variegated in
spots, veins, or clouds, arising from the intermixture of foreign substances.
Marble is essentially a carbonate of lime, which is composed of 57 parts of
lime and 43 parts of carbonic acid ; a little water is usually present. It is soluble
in nitric acid ; and, by the escape of carbonic acid, more or less effervescence is
1
2
PRACTICAL MASONRY
produced ; some varieties, however, effervesce very slowly. Before the blow-pipe
it decrepitates, and, if pure carbonate of lime, it is perfectly infusible ; but by a
strong heat its carbonic acid is driven off, and quicklime, or pure lime, whose
taste is well known, remains.
Marble, in the strict propriety of the term, should be confined to those varieties
of carbonate of lime which are susceptible of a polish ; including also some
minerals, in which carbonate of lime abounds. But among artists this term is
sometimes extended to serpentine, basalt, See., when polished.
Both granular and compact limestone furnish numerous varieties of marble ;
but those which belong to the former exhibit a more uniform color, are generally
susceptible of a higher polish, and are hence most esteemed for statuary and
some other purposes. The uniformity of color, so common in primitive marbles,
is sometimes interrupted by spots, or veins, or clouds, of different colors, arising
from the intermixture of hornblende, serpentine, &,c. Among the foreign marbles
we may mention : —
The Carrara Marble. Found at Carrara, in Tuscany. It was highly esteem-
ed by the ancients, and is at present more employed by the Italian artist than
any other kind for statuary, vases, slabs for household furniture, &.c. It is very
white, sometimes veined with gray, and has a grain considerably fine. In the
centre of the blocks of this marble very limpid rock-crystals are found, which are
called Carrara diamonds. The average price of this marble is ten or twelve dol-
lars a cubic foot.
The Liini Marble, found also in Tuscany, is extremely white, and its grain
is a little finer than that of Carrara. Of this marble, it is generally supposed, the
famous Apollo Belvidere, in the Vatican at Rome, is made, as well as the Antin-
oiis of the Capitol, and the Antinoiis in bas-relief in the Napoleon Museum.
The Parian JMarble, obtained from the islands of Paros, Naxos, &.C., in the
Archipelago, was much employed by the ancients. It is white, but often with a
slight tinge of yellow. Its grains are larger than those of the Carrara marble.
The celebrated Venus de Medicis, in the gallery at Florence, is of this marble.
It was called by the ancients Lychnites, in consequence of its quaraies being of-
ten worked by the light of a lamp. It is on Parian marble that the celebrated ta-
bles at Oxford are inscribed.
The Pentelic Marble. From Mount Penteles, near Athens. This marble
much resembles the preceding, but is more dense and fine-grained ; it sometimes
exhibits faint greenish zones, produced by greenish talc, whence the Italian
name Cipilino Statiiario. The principal monuments of Athens were of Pentelic
marble, such as the Parthenon, the Propylaea, and the Hippodrome. Among the
statues of this marble in the Napoleon Museum, at Paris, are the Torso; a
OF MARBLE.
3
Bacchus in repose ; a Jason (called Cincinnatus) ; a Paris ; the Discobolus reposing ;
the bas-relief known by the name of the Sacrifice ; the Throne of Satui-n ;
the Tripod of Apollo; and the two beautiful Athenian inscriptions known by the
name of “Xointel Marbles,” because M. Xointel caused them to be brought from
Athens to Paris in 1672.
Greek JVhite .Marble. The marble to which the statuaries of Rome give the
name of .Marino Greco is of a very bright snow-white color, close and fine-
grained, and of a hardness which is rather superior to that of other white mar-
bles. It takes a very fine polish. It has been called Corallic marble, from being
found near the river Coralus, in Phrygia. According to Pliny, it was found in
Asia, in masses of small dimensions ; and it is said that a similar kind occurs On
Mount Canuto, near Palermo, in Sicily. The Greek marble was obtained from
several islands in the Archipelago ; such as Scio, Samos, &ic. Among the
statues of this marble in the Napoleon Museum are a Bacchus, and Zeno, the
philosopher.
Translucid Jfliite .Marble. This much resembles Pai-ian marble, but differs
from it as being more translucid. There are, at Venice, and several other towns
in Lombardy, columns and altars of this marble, tbe quarries of which are
perfectly unknown.
Flexible JVhite .Marble. It is of a beautiful white color, and fine grain.
There are five or six tables of it preserved in the house of the Prince Borghese,
at Rome. They were dug up, as the Abbe Fortis was told, in the field of
Mondragone. Being set on end they bend, oscillating backward and forward ;
when laid horizontally, they form a curve.
JJliite .Marble of .Mount llymettus. This is not a very pure white variety, but
inclines a little to gray. Pliny informs us that Lucius Crassus, the orator, was
exposed to the sarcasms of Marcus Brutus, because he had adorned his house
with six columns, twelve feet high, of the Ilymettian marble. The statue of
Meleager, in the Napoleon Museum, is of this marble.
These are the chief white marbles which the ancients used for the purposes
of architecture and sculpture.
Black ^intique .Marble. (jYero .Intico of the Italians.) This differs from the
modern black marbles by the superior intensity of its color. It has been said
that the ancients procured this marble from Greece, but it has been ascertained
that quarries of real antique black marble have been rediscovered, which were
wrought by the ancients, and of which the remains are still to be seen, at the
distance of two leagues from Spa, towards Franchimont, not far from Aix-la-
Chapelle. This marble is extremely scarce, and occurs only in wrought pieces.
Red .inti que .Marble. {Rosso .intico oi the Italians.) This beautiful marble
4
PRACTICAL MASONRY.
is of a deep blood-red color, here and there with white veins, and, if closely
examined, is found to be sprinkled over with minute white dots, as if it were
strewed sand. Of this kind is the Egyptian Antinoiis, in the museum at Paris.
But the most esteemed variety of Rosso Antico is that of a very deep red,
without any veins, such as it is seen in the two antique chairs, and in the bust of
an Indian Bacchus in the same museum. The white spots, or points, which are
never wanting in the true red antique, distinguish it from others of the same
color. It is not known from wdience the ancients obtained this marble ; the
conjecture is that it was brought from Egypt. There is, in the Grimani Palace,
at Venice, a colossal statue of Marcus Agrippa, in Rosso Antico, \vhich w'as
formerly preserved in the Pantheon, at Rome.
Green Antique Marble. (The Verde Antico of the Italians.) This may be
considered a kind of breccia, the paste of which is a mixture of talc and lime-
stone; and the dark green fragments are owing to serpentine more or less
pure. The Verde x\ntico of the best quality is that of which the paste is of a
grass-green, and the blackish spots are of that variety of serpentine which is
called noble serpentine. This marble is much esteemed in commerce, but Icirge
pieces of a fine quality are seldom seen. There are four fine columns of it
in the Napoleon Museum ; but much more beautiful ones sre preserved at
Parma. This Verde Antico must not be confounded with the marbles known
by the names of Vert-de-mer or Vert -d’ Egypt. The real Verde Antico is a
breccia, and is never mingled with red spots, w'hile those just mentioned are
veined marbles, mixed with a dull red substance, which gives them a brownish
hue.
Red-spotted Green Antique Marble. Its ground is very dark green, here
and there marked with small red and black spots. The quarries of this mar-
ble are lost, and it is found only in small pieces, which are made into
tablets, &c.
Leek Marble. (Marbre Poireau of the French lapidaries.) This is a mix-
ture of limestone and a talcose substance of light green, shaded with blackish-
green, and related to serpentine. Its texture is filamentose, and, as it w^ere,
ligneous; its fragments are splintery. When polished it exhibits long green
veins. Like all other talcose marbles, it soon decomposes in the open air.
There is a table of it in the Plotel de la Monnoie, at Paris. Its quarries are lost.
Marble Petit Antique, of the French lapidaries. It is traversed wfith
white and gray veins, the two colors being disposed in uninterrupted threads ;
the tables made of this marble are irregularly striped their whole length, which
has a very fine effect. It is much esteemed, and only made use of for
inlaying ornamental furniture. Its quanies are unknown.
OF MARBLE.
S
Yellow Antique Marble. (Giallo Antico of the Italians.) Of this there
are three varieties. The first has more or less the color of the yolk of an
egg, and is nearly of an uniform tint ; the other is marked with black or deep
yellow rings, and the last is merely a paler colored variety of the first. These
different marbles, for which the Sienna marble is a good substitute, are found
only in small detached pieces, and in antique inlaid work. It is in this manner
that the two tables of lazulite in the Napoleon Museum are surrounded with
a border of the deep yellow variety.
Grand Antique Marble. This variety, which is a breccia, containing some
shells, consists of large fragments of a black marble united by veins, or lines,
of shining white. This superb marble, the quarries of which are lost, is
sometimes found in detached pieces and wrought. There are four columns
of it in the museum at Paris. A less valuable variety is that in which the
spots, instead of being an entire intense black, are of a gray color.
Antique CipoHn Marble. Cipolin is a name given to all such marbles as
have greenish zones, caused by green talc ; their fracture is granular and
shining, and shows here and there plates of talc. They are never found to
contain marine bodies. The ancients have made frequent use of cipolin. It
takes a fine polish, but its ribbon-like stripes always remain dull, and are that
part of the marble which first decomposes, when exposed to the open air.
There are modern cipolins as fine as that used by the ancients.
Purple Antique Breccia Marble. This should not be confounded with
African breccia. There is, perhaps, no marble, the color and spots of which
are so variable as that of the violet breccia. The following are the chief
varieties. The first is that from which the name of the marble is derived;
it has a purplish-brown base, in which are imbedded large angular fragments
of a light purple color, and others of a white color. This first variety can be
employed only in large works, on account of the size of its spots, which are
sometimes a foot in diameter. There is a beautiful table of it in the Napoleon
Museum. The second variety is, as it were, the miniature of the first ; it
exhibits the same spots, but within a much narrower compass, so that it may
be used for less gigantic works than those for which the other is employed.
The third variety is known in commerce by the name of rose-colored marble;
in this, the spots, instead of being white and light purple, have a pleasing rose-
color. It is scarce and never seen in large pieces. The fourth, which is the
[The term breccia, which has often been used In the preceding pages, is applied to an aggregate, composed
of angular fragments of the same or different minerals, united by some cement ; sometimes, however, a few
of the fragments are a little rounded. The different fragments always present a variety of colors. There
are several varieties, some of which are susceptible of a fine polish.]
6
PRACTICAL MASONRY.
most beautiful, appears, at first view, to be perfectly distinct from the others,
but it is, nevertheless, a mere variety of the purple breccia. Its ground is of
a yellowish -green color, and the spots, which are of various sizes, are white,
green, purplish, and yellow, mottled with red ; these various spots are traversed by
straight lines of grayish -white color. This fourth variety is very scarce. There
are, however, two tables of it at Paris, in the possession of private individuals.
Jlfrican Breccia Marble. Its ground is black, variegated with large fragments
of a grayish-white, of a deep red, or of a purplish wine-color; but these latter
are always smaller than the former. This is one of the most beautiful marbles
existing, and has a supurb effect when accompanied by gilt ornaments. Though
rather less vivid in its colors than the preceding violet breccia, it is yet, on the
whole, more beautiful. Whether Africa is the part of the world where it is
found, as its name implies, is not certain. The pedestal of Venus leaving the
Bath, and a large column, both in the Napoleon Museum, are of this marble.
There are other varieties of breccia marble, not differing materially from those
already described ; they are, many of them, very beautiful, but very scarce, found
only in small pieces among the ruins at Rome.
Marbles are found abundantly, and in variety, in all countries. There are many
curious varieties in the United States. The chief quarries that have been noticed
are the following : —
Slockbridge and Lanesboroiigfi Marble. In Berkshire county, Massachusetts.
Its grain is somewhat coarse, and its color white, sometimes with a slight tinge of
blue. A quarry has also been opened of a similar kind of marble, at Pittsfield,
in the same county.
Vermont Marble. It is found of various qualities, according to Professor
Hall, in many places on the west side of the Green Mountains. A few years
since, a valuable quarry was found in Middlebury, on Otter Creek, eleven miles
above Vergennes. The quarry forms one bank of the creek for several roods,
and extends back into the side of a hill, to a distance at present unknown.
The stone lies in irregular strata, varying considerably in thickness, but all more
or less inclined to the northwest. The marble is of different colors in
different parts of the bed. On one side it is of a pure white, and of a quality,
if at all, but little inferior to the Italian marble ; but this seems to constitute but
a small portion of the whole mass. The color that predominates through most
parts of the quairy is a gray of different intensities. The marble of both kinds
is solid, compact, free from veins of quartz, and susceptible of an excellent polish.
A mill of peculiar construction has been erected for the purpose of sawing the
stone into slabs. It contains sixty-five saws, which are kept almost in continual
operation. During the years of 1809 and 1810 these saws cut out 20,000 feet
OF M A E B L E .
7
of slabs, and the sales of marble tables, side-boards, tomb-stones, &c., in the same
period, amounted to about 11,000 dollars.
Some of the Vermont marbles are as white as the Carrara marble, with a grain
intermediate betwen that of the Carrara and Parian marbles.
S\'ew Haven Marble. The texture of this very beautiful marble is granular,
but very fine. Its predominant colors are gray and blue, richly variegated by veins
or clouds of white, black, or green ; indeed, the green often pervades a large
mass. It takes a high polish, and endures the action of fire remarkably well.
This marble contains chromate of iron, magnetic oxide of iron, and serpentine ;
hence it resembles the Vert Hntique, and is, perhaps, the only marble of the kind
hitherto discovered in America.
Thomaston Marble. From Lincoln county, Maine. It is, in general, fine-
grained, and its colors are often richly variegated. Sometimes it is white, or
grayish-white, diversified with veins of a dili’erent color. But, in the finest pieces,
the predominant color is gray, or bluish-gray, interrupted with whitish clouds,
which, at a small distance, resemble the minutely shaded parts of an engraving,
and, at the same time, traversed by innumerable stnall and irregular veins of black
and white. It receives a fine polish, and is well fitted for ornamental works.
Some of the white marble of A'ermont, and that which may be obtained at
Smithli. id, in Rhode Island, more peculiarly deserve the name of statuary marble.
Flcj'ible Marble has been observed at Pittsford, Rutland county, Vermont ;
and at Pittsfield, in Massachusetts.
Pennsylvania Marble. There is found at Aaronsburg, in Northumberland
county, a black marble. It is of compact limestone, containing white specks.
At Marbletown, near the Hudson River, in the State of New York, is a quany of
very fine black marble, spotted with white shells. Marble has also been found in
Virginia, and some other of the United States. But the state of the arts has not,
hitherto, directed the attention of the curious so much to this subject as it intrin-
sically deserves.
SECTION II. — The Polishing of Marble.
The art of cutting and polishing marble was, of course, known to the ancients,
whose mode of proceeding appears to have been nearly the same with that
employed at present ; except, perhaps, that they were unacquainted with those
superior mechanical means, which now greatly facilitate the labor, and diminish
the expense of the articles thus produced. There are many manufactories of
this kind, generally called marble-mills, on the continent, and also in Great Britain ;
8
PRACTICAL MASONRY.
but as the principle on which they proceed is nearly the same in all, it will suffice
in this place to give the description of one or two of the latter.
An essential part of the art of polishing marble is the choice of substances by
which the prominent parts are to be removed. The first substance should be the
sharpest sand, so as to cut as fast as possible, and this is to be used till the surface
becomes perfectly flat. After this, the surface is rubbed with a finer sand, and
frequently with a third. The next substance, after the finest sand, is emery, of
difierent degrees of fineness. This is followed by the red powder called tripoli,
which owes its cutting quality to the oxide of iron it contains. Common iron-
stone, powdered and levigated, answers the purpose very well. This last
substance gives a tolerably fine polish. This, however, is not deemed sufficient.
The last polish is given with putty. After the first process, which merely takes
away the inequalities of the surface, the sand employed in preparing it for the
emery should be chosen of an uniform quality. If it abounds with some particles
harder than the rest, the surface will be liable to be scratched so deep as not to
be removed by the emery. In order to get the sand of uniform quality, it should
be levigated and washed. The hard particles being generally of a different
specific gravity to the rest, may, by this means, be separated. This method will
be found much superior to that of sifting. The substance by which the sand
is rubbed upon the marble is generally an iron plate, especially for the first
process. A plate of an alloy of lead and tin is better for the succeeding
processes, with the fine sand and emery. The rubbers used for the polishing, or
last process, consist of coarse linen cloths, such as hop- bagging, wedged tight
into an iron plane. In all of these processes, a constant supply of water, in small
quantities, is absolutely necessary.
The sawing of marble is performed on the same principles as the first process
of polishing. The saw is of soft iron, and is continually supplied with w'ater and
the sharpest sand.
Marble is extensively used for building, statuary, decorations, and inscriptions.
In warm countries it is one of the most durable of substances, as is proved by
the edifices of Athens, which have retained their polish for more than two
thousand years. Severe frost, preceded by moisture, causes it to crack and scale;
great heat reduces it to quicklime. It may be burnt, like other varieties of lime-
stone, into lime for preparing mortar, or employed as a flux for certain ores,
particularly those which contain alumine and silex.
White marble is sometimes cleaned by muriatic acid diluted with water. Spots
of oil stain white marble, so that they cannot be taken out.
OF MARBLE.
9
SECTION III. — Artificial Marble.
The stucco, whereof they make statues, busts, basso-relievos, and other
ornaments of architecture, ought to be marble pulverized, mixed in a certain
proportion with plaster; the whole well sifted, worked up with water, and used
like common plaster. (See Stucco.)
There is also a kind of artificial marble, made of flake selenites, or a trans-
parent stone resembling the plaster, which becomes very hard and receives a
tolerable polish, and may deceive the eye. This kind of selenites resembles
Muscovy talc. There is another sort of artificial marble, formed by corrosive
tincture, which, penetrating into white marble, to the depth of a line or more,
imitates the various colors of other dearer marbles. There is also a preparation
of brimstone in imitation of marble. To do this you must provide yourself with
a flat and smooth piece of marble. On this make a border or wall, to encompass
either a square or oval table, which may be done either with wax or clay. Then,
having provided several sorts of colors, as white lead, vermilion, lake, orpiment,
massicot, Prussian-blue, &cc., melt, on a slow fire, some brimstone, in several
glazed pipkins ; put one particular sort of color into each, and stir it well together;
then, having before oiled the marble all over within the wall, with one color quickly
drop spots upon it of larger and less size ; after this take another color, and do
as before ; and so on, till the stone is covered with spots of all the colors you
design to use. When this is done, you are next to consider what color the mass
or ground of your table is to be ; if of a gray color, then take fine sifted ashes,
and mix them up with melted brimstone, or if red, with English red ochre; if
white, with white lead; if black, with lamp or ivory black. Your brimstone for
the ground must be pretty hot, that the colored drops on the stone may unite and
incorporate with it. When the ground is poured even all over, you are next, if
judged necessary, to put a thin wainscot board upon it ; this must be done while
the brimstone is hot, making also the board hot, which ought to be thoroughly
dry, in order to cause the brimstone to stick the better to it. When the whole is
cold, take it up, and polish it with a cloth and oil, and it will look very beautiful.
Iv A S'
SECTION IV. — The Coloring of Marble.
The coloring of marble is a nice art, and, in order to succeed in it, the pieces
of marble on which the experiments are tried must be well polished, and clear
2
10
PRACTICAL MASONRY.
from the least spot or vein. The harder the marble is, the better it will be, and
the greater the heat necessary in the operation ; therefore, alabaster, and the
common soft white marble, are very improper to perform these operations upon.
Heat is always necessary, for the opening of the pores, so as to render it fit to
receive the colors ; but the marble must never be made red-hot, for then the
texture of the marble itself is injured, and the colors are burnt, and lose their
beauty. Too small a degree of heat is as bad as too great ; for, in this case,
though the marble receives the color, it will not be fixed in it, nor strike deep
enough. Some colors will strike even cold ; but they are never so well sunk in
as when a just degree of heat is used. The proper degree is that, which,
without making the marble red, will make the liquor boil on its surface. The
menstruums used to strike in the colors must be varied according to the nature
of the color to be used. A lixivium made of horse’s or dog’s urine, with four
parts of quicklime, and one part pot-ashes, is excellent for some colors ; common
lye of wood-ashes does very well for others; for some, spirit of wine is best;
and finall}^ for others, oily liquors, or common white wine.
The colors which have been found to succeed best with the peculiar menstru-
ums, are these : stone-blue dissolved in six times the quantity of spirit of wine,
or of the urinous lixivium, and that color which the painters call litmus dissolved
in common lye of wood-ashes. An extract of saffron, and that color made of
buckthorn berries, and called by the painters soap-green, both succeed well dis-
solved in urine and quicklime, and tolerably well in spirit of wine. Vermilion, and
a fine powder of cochineal, succeed also very well in the same liquors. Dragon’s-
blood succeeds very well in spirit of wine, as does also a tincture of logwood in
the same spirit. Alkanet-root gives a fine color, but the only menstruum to be
used for this is oil of turpentine ; for neither spirit of wine, nor any lixivium, will
do with it. There is a kind of substance called dragon’s-blood-in-tears, which,
mixed with urine alone, gives a very elegant color.
Besides these mixtures of colors and menstruums, there are some colors which
are to be laid on dry and unmixed. These are dragon’s-blood of the purest
kind, for a red ; gamboge, for a yellow ; green wax, for a green ; common brim-
stone, pitch, and turpentine, for a brown color. The marble, for these experi-
ments, must be made considerably hot, and the colors are to be rubbed on dry,
in the lump. Some of these colors, when once given, remain immutable ; others
are easily changed or destroyed. Thus the red color, given by dragon’s-blood,
or by the decoction of logwood, will be wholly taken away by oil of tartar, and
the polish of the marble not hurt by it.
A fine gold color is given in the following manner: take crude sal-ammoniac.
OF MARBLE.
11
vitriol, and verdigris, of each equal quantities ; "white vitriol succeeds best, and
all must be thoroughly mixed in fine powder.
The staining of marble, to all degrees of red or yellow, by solution of dragon’s-
blood or gamboge, may be done by reducing these gums to powder, and grinding
them with the spirit of wine, in a glass mortar; but for smaller attempts, no
method is so good as the mixing a little of either of these powders with spirit
of wine, in a silver spoon, and holding it over burning charcoal. By this means,
a fine tincture will be extracted, and, with a pencil dipped in this, the finest traces
may be made on the marble, while cold, which, on heating of it afterwards, either
on sand or in a baker’s oven, will all sink very deep, and remain perfectly distinct
in the stone. It is very easy to make the ground-color of the marble red or
yellow, by this means, and leave white veins in it. This is to be done by covering
the places where the whiteness is to remain with some white paint, or even with two
or three doubles only of paper, either of which will prevent the color from pene-
trating in that part. All the degrees of red are to be given to the marble by the
means of this gum alone ; a slight tincture of it, without the assistance of heat
to the marble, gives only a pale fleshcolor; but the stronger tinctures give it yet
deeper. To this the assistance of heat adds yet greatly ; and finally, the addition
of a little pitch to the tincture gives it a tendency to blackness, or any degree
of deep red that is desired.
A blue color may be given to marble, by dissolving turnsol in a lixivium of lime
and urine, or in the volatile spirit of urine ; but this has always a tendency to
purple, whether made by one or the other of these ways. A better blue, and
used in an easier manner, is furnished by the Canary turnsol, a substance well
known among the dyers. This need only be dissolved in water, and drawn on
the place with a pencil ; this penetrates very deep into the marble, and the color
may be increased by drawing the pencil, wetted afresh, several times over the
same lines. This color is subject to spread and diffuse itself irregularly; but it
may be kept in regular bounds, by circumscribing its lines with beds of wax, or
any other substance. It is to be observed, that this color should always be laid
on cold, and no heat given ever afterwards to the marble ; and one great advan-
tage of this color is, that it is easily added to marbles already stained with any
other colors, and it is a very beautiful tinge, and lasts a long time.
This art has, in several persons’ hands, been a very lucrative secret, though
there is scarcely any thing in it, that has not, at one time or another, been
published.
Kircher has the honor of being one of the first who published any thing
practicable about it. This author, meeting with stones in some cabinets, supposed
to be natural, but having figures too nice and particular to be supposed to be
12
PRACTICAL MASONRY.
Nature’s making, and these not only on the surface, but sunk through the whole
body of the stones, was at the pains of finding out the artist who did the business ;
and on his refusing to part with the secret on any terms, this author, with Albert
Gunter, a Saxon, endeavoured to find it out. Their method is this. Take nitric
acid and nitro-muriatic acid, of each one ounce, sal-ammoniac one ounce, spirit
of wine two drachms, about twenty-six grains of gold, and two drachms of pure
silver ; let the silver be calcined and put into a vial, and pour upon it the nitric
acid ; let this stand some time, then evaporate it, and the remainder will at first
appear of a blue, and afterwards of a black color ; then put the gold into another
vial, and pour the nitro-muriatic acid upon it, and when it is dissolved, evaporate
it as the former ; then put the spirit of wine upon the sal-ammoniac, and let it be
evaporated in the same manner. All the remainders, and many others made in
the same manner from other metals, dissolved in their proper acid menstrua, are
to be kept separate, and used with a pencil on the marble. These will penetrate
without the least assistance of heat, and, the figure being traced with a pencil on
the marble, the several parts are to be touched over with the proper colors, and
this renewed daily, till the colors have penetrated to the desired depth into the
stone.
After this, the mass may be cut into thin plates, and every one of them will
have the figure exactly represented on both surfaces, the colors never spreading.
The nicest method of applying these, or the other tinging substances, to marble
that is to be wrought into any ornamental works, and where the back is not
exposed to view, is to apply the colors behind, and renew them often, till the
figure is sufficiently seen through the surface on the front, though it does not
quite extend to it. This is the method that, of all others, brings the stone to a
nearer resemblance of natural veins of this kind. The same author gives another
method to color marble, by vitriol, bitumen, &c. Forming a design of what you
like upon paper, and laying the said design between two pieces of polished
marble, then, closing all the interstices with wax, you bury them for a month or
two in a damp place ; on taking them up, you will find that the design you
painted on the paper has penetrated the marbles, and formed exactly the same
design upon them.
SECTION V. — Granite.
Granite is apparently the oldest and deepest of rocks. It is one of the
hardest and most durable which have been wrought, and is obtained in larger
pieces than any other rock. Granite is a compound stone, varying in color and
OF GRANITE.
13
coarseness. It consists of three constituent parts, united to each other without the
intervention of any cement, namely, quartz, the material of rock-crystal ; feldspar,
which gives it its color ; and lastly mica, a transparent, thin, or foliated substance.
But in order to understand more perfectly the nature and qualities of granite,
some examination of its constituent parts is necessary.
I. Quartz belongs to that class of minerals denominated earthy compounds, or
stones. It embraces numerous varieties, differing much in their forms, texture,
and other external characters. And although but few well defined external
characters apply to the whole species, yet most of its varieties are easily recognized.
It is sufficiently hard to scratch glass, and it always gives sparks with steel.
When pure, its specific gravity is about 2.63, water being 1 ; but in certain
varieties extends above and below this term, depending on its structure, or the
presence of foreign ingredients. Indeed the mean specific gravity of the whole
species is about 2.60. It is sometimes in amorphous masses, and sometimes in
very beautiful crystals, of which the primitive form is a rhomb slightly obtuse, the
angles of its faces being 94“ 24' and 85“ 36'. The secondary form, the most
common, is a six-sided prism, terminated by six-sided pyramids. It exhibits
double refraction, which must be observed by viewing an object through one face
of the pyramid and the opposite side of the prism. Its fracture is vitreous.
Chemical Characters. All the varieties of quartz are infusible by the blow-pipe,
and if pure, it is scarcely softened, even when the flame is excited by oxygen
gas. Before the compound blow-pipe, a fragment of rock-crystal instantly melts
into a white glass. Quartz is essentially composed of silex, or the principal
ingredient of flint, from 93 to 98 parts being of this substance, and the residue
alumine, lime, water, or some metallic oxide.
Among the varieties, are, — 1. The Limpid Quartz (Rock-crystal). This, the
most perfect variety of quartz, has, when crystallized, received the name of rock-
crystal ; indeed the same name is sometimes extended to colored crystals, when
transparent. Limpid quartz is without color, and sometimes as transparent as the
most perfect glass, which it strongly resembles. It is, however, harder than glass,
and the flaws or bubbles, which it often contains, lie in the same plane, while
those in glass are irregularly scattered. The finest crystals are found in veins,
or cavities, in primitive rocks, as in granite, gneiss, or mica slate, or in alluvial earths.
In the United States this variety is not uncommon. It is found in Virginia,
near the North Mountain. In Frederick county, Maryland, crystals are scat-
tered on the surface of the ground, of perfect transparency, with a splendid lustre.
In New York, on an island in Lake George, are very fine crystals, — and in
Vermont, at Grafton. This variety is sometimes employed in jewelry, for watch-
seals, &LC.
14
PRACTICAL MASONRY.
2. Smoky Quartz. Objects seen through this variety, seem to be viewed
through a cloud of smoke. Its true color seems to be clove-brown. It is some-
times called smoky topaz.
3. Yellow Quartz. Its color is pale yellow, sometimes honey or straw-yellow.
It has been called citrine ; and also false, or Bohemian, topaz.
4. Blue Quartz. Its color is blue, or grayish-blue. It is inferior in hardness
to the former varieties.
5. Rose-red Quartz. Its color is rose -red, of different shades, sometimes
with a tinge of yellow. It is seldom more than semi-transparent. Its color,
which is supposed to arise from manganese, is said to be injured by exposure to
light. It has been called Bohemian ruby. It is sometimes employed in jewelry,
and much esteemed.
6. Irised Quartz. It reflects a series of colors, similar to those of the iris or
rainbow.
7. .dventurine Quartz. Its predominant color, which may be red, yellow,
gray, greenish, blackish, or even white, is variegated by brilliant points, which
shine with silver or golden lustre. It is sometimes employed in ornaments of
jewelry.
8. Milky Quartz. Its color is milk-white, in some cases a little bluish ; and
it is nearly opaque. Its fracture has sometimes a resinous lustre. It is some-
times in small crystals, but more often in large masses.
9. Greasy Quartz. Its colors are various, either light or dark. Its fracture
appears as if rubbed with oil.
10. Radiated Quartz. It is in masses which have a crystalline structure,
and are composed of imperfect prisms. These prisms usually diverge a little,
or radiate from the centre, and often separate with great ease.
11. Tabular Quartz. It occurs in plates of various sizes, which are some-
times applied to each other by the broader faces.
12. Granular Quartz. Its structure presents small granular concretions, or
grains, which are sometimes feebly united. This variety must be carefully dis-
tinguished from certain sandstones which it resembles. It may be important in
the manufacture of glass, and certain kinds of stone ware.
13. .Arenaceous Quartz. It is in loose grains, coarse or fine, either angular or
rounded, and constitutes some varieties of pure sand. Certain sandstones
appear to be composed of this quartz, united by some cement.
14. Pseiidomorphous Quartz. It appears under regular forms, such as cubes,
octahedrons, &c., which do not belong to the species. They are opaque, their
surfaces dull, and their edges often blunted.
Common quartz never forms whole mountains. It is sometimes in large
OF GRANITE.
15
masses, or in beds, and frequently in extremely large veins, which have been
mistaken for beds. Quartz, in the form of crystallized grains, or of irregular
masses of various sizes, is abundantly disseminated in granite, gneiss, mica slate,
&c., of all which it forms a constituent part. It is sometimes in regular crystals,
dispersed through the granite. In porphyry, also, it is sometimes regularly crys-
tallized. It also occurs in carbonate of lime, anthracite, &c. Among secondary
rocks, quartz is found, forming a greater part of many sandstones ; also between
strata of compact limestone, of clay, or of marl, or imbedded in sulphate of lime.
In alluvial earths it exists in the form of sand. Quartz is often associated with
the carbonate and fluate of lime, sulphate of barytes, and feldspar, in metallic
veins ; indeed, it exists in almost every metallic vein.
Hornblende, schorl, epidote, garnet, magnetic iron, are also among the minerals
contained in quartz. Mica gives it a slaty structure.
In some rare instances, bubbles of air, and even drops of water, and bitumen,
have been found in quartz. Although common quartz never contains any organic
remains, it is sometimes crystallized in fossil wood.
Quartz is found very abundantly in most of the Northern and Middle States.
We have already seen that certain varieties of quartz are employed in jewelry.
It is also used, especially the sandy variety, in the manufacture of glass ; also in
the preparation of smalt and certain enamels.
II. Feldspar. This important and widely distributed mineral has, in most of
its varieties, a structure very distinctly foliated. It scratches glass, and gives
sparks with steel, but its hardness is a little inferior to that of quartz. When in
crystals or crystalline masses, it is very susceptible of mechanical division, at
natural joints, which, in two directions perpendicular to each other, are extremely
perfect ; but in the third direction they are usually indistinct.
The primitive form, thus obtained, is an oblique-angled parallelogram, whose
sides are inclined to each other in angles of 90°, 120°, and 111° 28'. The four
sides, produced by the two divisions perpendicular to each other, have a brilliant
polish, while the two other sides are dull ; this is a distinctive character of great
importance. Its specific gravity usually lies between 2.43 and 2.70. It possesses
double refraction, which, however, is not easily observed. It is usually phospho-
rescent, by friction, in the dark.
Chemical Characters. Before the blow-pipe it melts into a white enamel, or
glass, more or less translucent. The results of analysis have not yet been per-
fectly satisfactory in regard to the true composition of feldspar. It appears prob-
able, however, that not only silex and alumine, but also lime and potash, are
essential ingredients. In a specimen of green feldspar, Vauquebin found 62.88
16
PRACTICAL MASONRY.
parts of silex, 17.02 of alumine, 13.0 of potash, 3.0 of lime, and 1.0 of oxide of
iron, = 96.85 in a hundred parts.
Several of the varieties of feldspar deserve notice.
1. Common Feldspar. This variety occurs in fragments often rolled, also in
grains in sand, but more commonly in masses of moderate size, forming an ingre-
dient of compound minerals. It is not unfrequently in regular crystals of the
primitive form, already mentioned.
The crystals of feldspar, seldom very small, are sometimes several inches both
in diameter and length ; their faces are shining, and their edges sometimes very
perfect. Their prevailing form is an oblique prism, whose sides are unequal, and
vary in number, from four to ten. The terminating faces, of which two are
commonly longer than the others, are subject to great variation in number and
extent ; indeed, they often seem to have no symmetry in their arrangement, a
circumstance which arises from the obliquity and irregularity of the primitive
form.
The longitudinal fracture is foliated, and its lustre more or less shining and
vitreous, sometimes pearly, especially in certain spots ; the cross fracture is
uneven or splintery, and nearly dull. It is easily broken, and falls into rhomboidal
fragments, which have four polished faces. The folia are sometimes curved, or
arranged like the petals of a flower.
It is more or less translucent, sometimes nearly or quite opaque, and presents
a great variety of coloi’s. Among these are white, tinged with gray, yellow, green,
or red ; gray, often with a shade of blue ; several shades of red, as flesh or
blood-red ; to which must be added green, yellow, brown, or even black.
This variety is abundant, and constitutes an essential ingredient of granite,
gneiss, sienite, and greenstone. Of granite and sienite it sometimes forms
two thirds of the whole mass. It exists also in argillite and porphyry, &c. Its
crystals, though sometimes imbedded, are more often found in the fissures or
cavities of these rocks, and are sometimes associated with epidote, axinite,
chronite, amianthus, carbonate of lime, quartz, magnetic oxide of iron, &c.
2. Green Feldspar. The variety is rare, and has an apple-green color, varying
somewhat in intensity, and sometimes marked with whitish stripes.
3. Adularia. This is the most perfect variety of feldspar, and bears to com-
mon feldspar, in many respects, the relation of rock-crystal to common quartz.
It is more or less translucent, and sometimes transparent and limpid. Its color is
white, either a little milky, or with a tinge of green, yellow, or red. But it is
chiefly distinguished by presenting, when in certain positions, whitish reflections,
which are often slightly tinged with blue or green, and exhibit a pearly or silver
lustre. Adularia is sometimes cut into plates and polished. The fish’s eye moon-
OF GRANITE.
17
stone and argentine of lapidaries come chiefly from Persia, Arabia, and Ceylon,
and belong to adularia, as do also the water-opal and girasole of the Italians.
4. Opalescent Feldspar. This very beautiful variety is distinguished by its
property of reflecting light of different colors, which appear to proceed from its
interior. Its proper color is gray, often dark or blackish-gray, and sometimes
specimens are marked with whitish spots or veins. But when held in certain
positions it reflects a very lively and beautiful play of colors, embracing almost
every shade of green and blue, and several shades of yellow, red, gray, and
brown. These colors are usually confined to certain spots, and even the same
spot changes its color in different positions. It is much esteemed in jewelry.
5. Acenturine Feldspar. Its colors are various ; but it contains little spangles
or points, which reflect a brilliant light.
6. Petuntze. It is nearly or quite opaque, and its color is usually whitish or
gray. It has, in most cases, less lustre than common feldspar. It most usually
occurs in beds. Its powder is said to have a slightly saline taste. It is used in
the manufacture of porcelain, both for an enamel and its composition.
7. Granular Feldspar. It is nearly or quite opaque, and imperfectly foliated.
It varies much in hardness, and is sometimes friable between the fingers. Its
color is usually white, and sometimes strongly resembles masses of white sugar.
Feldspar is found in the Northern, and most of the Middle States.
III. Mica. Mica appears to be always the result of crystallization, but it is
rarely found in regular, well-defined crystals. Most commonly it appears in
thin, flexible, elastic laminae, which exhibit a high polish and strong lustre. These
laminae have sometimes an extent of many square inches ; and from this grad-
ually diminish, till they become mere spangles. They are usually found united
into small masses, extremely variable in thickness, or into crystals more or less
regular ; their union, however, is so very feeble, that they are easily separable,
and may be reduced to a surprising degree of tenuity. In this state their surface
becomes irised, and their thickness does not exceed a millionth part of an inch.
The crystals of mica are sometimes right prisms with rhombic bases, whose
angles are 120° and 62°. This is also the primitive form, in which one side of
the base is to the height of the prism nearly as 3 to 8.
The structure of mica is always foliated, but the foliae may be straight, curved,
or undulated. The surface has a shining or splendent lustre, which is usually
metallic, sometimes like that of silver or gold ; and sometimes like that of polished
glass. It is easily scratched by a knife, and, in most cases, even by the finger-
nail. Its surface is smooth to the touch, and very seldom slightly unctuous ; its
powder is dull, grayish, and feels soft. It is often transparent ; in other cases it
3
18
PRACTICAL MASONRY,
is only translucent, sometimes at the edges only. Its colors are silver-white, gray,
often tinged with yellow, green, or black ; also, brown, reddish, and green.
Its specific gravity extends from 2.53 to 2.93 ; and when rubbed on sealing-
wax, it communicates to the wax negative electricity.
Chemical Characters. It is fusible by the blow-pipe, though sometimes
with difficulty, into enamel, which is usually gray or black. The colored varieties
are the most easily fusible ; and black mica gives a black enamel, which often
moves the needle. It contains, according to Klaproth, silex 48.0, alumine 34.25,
potash 8.75, oxyd of iron 4.5, oxyd of manganese 0.5,^= 96. Sometimes the
potash is in greater proportion, and in black mica the oxyd of iron is sometimes
as high as 22 per cent. Mica is subject to decomposition by exposure to the
atmosphere.
The following are the most important varieties of mica : —
1. Laminated Mica. It occurs in large plates, which often contain many
square inches. It has been called Muscovy glass, or talc, being found abundantly
in that country.
2. Lamellar Mica. This is the more common variety. It exists in small
foliae, either collected into masses, or disseminated in other minerals. It is
sometimes in extremely minute scales, which, when detached from the mass,
appear like sand.
3. Prismatic Mica. This variety is not common. The laminae are easily
divisible, parallel to their edges, into minute prisms, or even into delicate filaments.
The edges of the laminae have usually more lustre than those of the other
varieties.
Although mica never occurs in beds, or large insulated masses, there is no
substance more universally diffused through the mineral kingdom. It is an
essential ingredient in granite, gneiss, and mica-slate ; and occurs also in sienite,
porphyry, and other primitive rocks. Mica occurs also in greenstone, basalt,
sandstone, and other secondary rocks, especially in sandstone and shell, which
accompany coal.
In the United States mica is very abundant.
It has been employed, instead of glass, in the windows of dwelling-houses ;
also in ships of war, because it is not liable to be broken by the concussion
produced by the discharge of cannon. In lanterns it is superior to horn, being
more transparent, and not so easily injured by heat. When in thin, transparent
laminae, sufficiently large, it is useful to defend the eyes of those who travel,
against high winds and severe storms of snow. When of suitable color and in
minute scales, it is employed to ornament paper, which is then said to be frosted ;
the scales of mica are made to adhere by a solution of gum or glue.
These are the ingredients of which granite is composed.
OF GRANITE.
19
The structure of granite is granular; but the grains are extremely variable,
both in size and form. Most frequently the size of the grains lies between that
of a pin’s head and a nut. Sometimes, however, they are several inches, and
even more than a foot, in their dimensions, and sometimes they are so minute,
that the mass resembles a sandstone, or even appears almost homogeneous to
the naked eye.
The forms of these grains are, in general, altogether irregular, like those of the
fragments of most minerals. In some granites the feldspar or quartz, or even
the mica, is in crystals more or less regular.
The ingredients of granite vary much in their proportions ; but, in general, the
feldspar is most abundant, and the mica is usually in the smallest proportion.
Their arrangement is also various : sometimes, while the feldspar and quartz are
mingled with considerable uniformity, the mica appears only in scattered masses,
or is found investing grains of feldspar and quartz on all sides ; in other cases
the feldspar and mica, or quartz and mica, are mingled, while the third ingredient
appears in small, distinct masses.
One of the ingredients of this rock, most frequently the quartz or mica, may
be entirely wanting, through a greater or less portion of the mass, so that speci-
mens of true granite (as it is sometimes called) contain only two ingredients.
The predominant color of granite usually depends on that of the feldspar,
which may be white or gray, sometimes with a shade of red, yellow, blue, or
green, and sometimes it is flesh-red. The quartz may be white, grayish-white,
or gray, sometimes very dark ; but it is usually vitreous and translucent. The
mica may be black, brown, gray, silver-white, yellowish, or violet.
The simple minerals which enter into the composition of granite are, in general,
so intimately united, that the mass is firm and solid ; but some varieties are brittle,
and easily become disintegrated. The feldspar sometimes undergoes a partial
decomposition, losing its lustre, hardness, and foliated structure, while, at other
times, it is converted into porcelain clay. The mica, also, when exposed to the
open air, is subject to alteration, or even decomposition. Sulphuric acid is often
generated by the decomposition of the sulphuret of iron, disseminated in che
granite, and this acid acts upon the mica in its vicinity, thus producing a soft
substance, and diminishing the firmness of the granite. Granite which embraces
short is also liable to disintegration.
The specific gravity of granite generally lies between 2.5 and 2.6, but is
sometimes higher.
Among the varieties of granite are, —
1. Graphic Granite. This very beautiful variety of granite is composed
chiefly of feldspar and quartz. The feldspar is very abundant, forming a base,
20
PRACTICAL MASONRY.
in which quartz, under various forms, lies imbedded. When this granite is
broken in a direction perpendicular to that in which the quartz traverses the
feldspar, the surface of the fracture ordinarily presents the general aspect of
letters^ arranged in parallel lines ; and hence its name. These letters of gray,
vitreous quartz, on a shining and polished tablet of white or flesh-colored feld-
spar, appear extremely beautiful. It is principally this variety of granite which,
by its decomposition, furnishes porcelain clay.
2. Globular Granite. This is composed of large, globular, distinct concretions,
which are sometimes several feet in diameter. These concretions are united by
a kind of granite, which is readily disintegrated, thus leaving the globular masses
detached from each other.
3. Porphyritic Granite. This variety is produced, when large crystals of
feldspar are interspersed in a fine-grained granite.
Granite is always a primitive rock ; and never embraces any organic remains
of animals or vegetables.
It exists very extensively, and in many countries it occurs in immense quan-
tities. It constitutes a large portion of many of the highest mountains, of which
it appears to form the central parts, as well as the summits. It is more or less
abundant in the mountains of Scotland and Germany ; the Alps, the Carpathian,
the Uralian, and the Altaian mountains ; the Andes, and the United States.
Granite is chiefly used as a building stone. It is split from the quarries by
rows of iron wedges, driven simultaneously in the direction of the intended fis-
sure. This method is thought by Brard to have been known to the ancient
Romans and Egyptians. The blocks are afterwards hewn to a plane surface,
by the strokes of a sharp-edged hammer. Granite is also chiselled into capitals
and decorative objects, but this operation is difficult, owing to its hardness and
brittleness. It is polished, by long-continued friction, with sand and emery.
The largest mass of granite knowm to have been transported, in modem
times, is the pedestal of the equestrian statue of Peter the Great, at St. Peters-
burg. It is computed to weigh three million pounds, and w^as transported nine
leagues, by rolling it on cannon-balls; those of iron being crushed, others of
bronze were substituted. Sixty granite columns, at St. Petersburg, consist each
of a single stone, twenty feet high. The columns in the portico of the Pan-
theon, at Rome, which are thirty-six feet eight inches high, are also of granite.
The shaft of Pompey’s Pillar, in Egypt, is sixty-three feet in height, and of a
single piece. It is said to be of red granite, but is possibly sienite. In the east-
ern part of the United States, a beautiful white granite is found in various places,
and is now introduced into building. The Quincy Market-house in Boston, the
United States Bank, the Tremont House, the Tremont Temple, &c., are made
of it.
OF SIENITE.
21
SECTION VI. — SiENiTE.
This rock is related to granite, and resembles it in its general characters.
Feldspar and hornblend may be considered its constant and essential ingredients.
Feldspar is the most abundant ingredient, and has already been described (see
Granite) ; but as it is, however, the presence of hornblend as a constituent
part which distinguishes this rock from granite, some account of it may be
useful.
I. Hornblend is a very common mineral, and may, in general, be easily
recognized. Sometimes it is in regular and distinct crystals, but more common-
ly it appears in masses, composed of laminae, or fibres, variously aggregated,
the result of confused crystallization.
When its structure is sufficiently regular, mechanical division is easily effected
in a longitudinal direction ; and its crystals are found to be composed of laminae,
situated parallel to the sides of an oblique four-sided prism, with rhombic bases ;
the sides of this prism are inclined to each other, at angles of 124° 34' and
55° 26'. The longitudinal fracture is of course foliated, and usually presents
the broken edges of many laminae extending one beyond another.
Hornblend usually scratches glass, and sometimes with difficulty gives sparks
with steel. Its powder is dry, and not soft to the touch. It is often opaque,
sometimes translucent. It is generally black and green, often intermixed. Its
specific gravity is about 3.20.
Chemical Characters. Before the blow-pipe it melts with considerable ease,
and forms black or grayish-black glass, or grayish enamel. It yields, by analy-
sis, silex, alumine, magnesia, and lime, but in variable proportions. Its colors
are produced by the oxyds of iron and of chrome.
Masses of hornblend, whether fibrous, lamellar, or nearly compact, possess a
remarkable tenacity, which renders them tough and difficult to break ; indeed,
a considerable cavity may often be produced by the hammer, before the mass
breaks. They exhale, when moistened by the breath, a peculiar argillaceous
odor.
Some of the varieties are, —
1. Basaltic Hornblend, which is found in lava and volcanic scoriae, and very
often in basalt ; and hence its name. It is almost always in distinct crystals,
whose color is a pure black, sometimes slightly tinged with green, or brownish,
by decomposition. Their surface is sometimes strongly shining, at other times
22
PRACTICAL MASONRY.
dull, and invested with a ferruginous crust. Its structure is more foliated than
that of other varieties, and its crystals more brittle.
2. Lamellar Hornblend. Its masses are sometimes composed merely of lam-
ellar, and sometimes of granular, concretions of various sizes, having a lamellated
structure. Hence the fracture is foliated, but the foliae are variously inclined
and interlaced.
3. Fibrous Hornblend. It occurs in masses, composed of acicular crystals or
fibres, either broad or narrow, parallel or interlaced.
4. Slaty Hornblend, or Hornblend Slate. This variety scarcely differs from
the preceding, except in the slaty structure of its masses. For each individual
layer is composed of very minute fibres, diverging in bundles, or promiscuously,
and often interlaced.
Hornblend is an essential ingredient in sienite and greenstone, as well as in
basalt and lava.
Sienite, being composed of these two ingredients, is usually granular ; but the
grains are sometimes coarse, and sometimes very fine. In some instances its
structure is slaty. When this rock is very fine grained, and, at the same time,
contains large crystals of feldspar, it constitutes sienitic porphyry.
The feldspar, whose foliated texture is often very distinct, is most frequently
reddish or whitish ; but sometimes it receives a greenish tinge from the horn-
blend, or from epidote.
Sienite is sometimes found resting on granite, gneiss, mica-slate, or argillite,
and sometimes it is associated with greenstone and argillaceous porphyries.
This rock is often altered at the surface by the action of the weather, more
especially in those varieties which contain an uncommon proportion of feldspar.
It often is susceptible of a good polish ; and may be employed for the same
purposes as porphyry. Its name is derived from that of Sienna, a city in Egypt,
where it is found in abundance, and constitutes the material of many of the obe-
lisks. The Romans imported it for purposes of statuary and architecture.
Sienite is obtained in large pieces, and possesses all the valuable qualities of
granite as a building stone. It is somewhat harder than granite, and more dif-
ficult to chisel. It is found abundantly near Boston, at Weymouth, Brighton,
Quincy, &c., and is introduced into many structures. The Washington Bank
and the Bunker Hill Monument consist of this stone. It is rendered, by its ex-
treme hardness, one of the best materials for macadamizing roads. The railway
at Quincy is built for transporting this stone from the quarry to the sea, and it is
there commonly called the Quincy stone.
OF GREENSTONE.
23
SECTION VII. — Greenstone.
SiENiTE and greenstone are essentially composed of the same ingredients,
x\2i.mQ\y, feldspar and hornblend. And the two rocks do, in fact, pass into each
other by insensible shades. But in greenstone the hornblend predominates,
while in sienite the feldspar is the most abundant ingredient. This frequently
gives to this stone more or less of a greenish tinge, especially when it is mois-
tened ; hence the name of this rock. Sometimes the tinge of green is consid-
erable lively ; sometimes, also, its color is a dark gray, or grayish-black. In
short, its color, especially at the surface, is often modified by the presence of
oxyd of iron.
It presents a considerable diversity of aspect, depending on the general struc-
ture, or on the size, proportion, disposition, and more or less intimate mixture
of its constituent parts. From greenstone, with a coarse granular structure, to
those varieties whose texture is so finely granular that the tw'o ingredients can
scarcely be perceived, there is a gradual passage, exhibiting every intermediate
step. Indeed, the grains are sometimes so minute, and so uniformly and in-
timately mingled, that the mass appears altogether homogeneous, and the dif-
ferent ingredients are hardly perceptible, even with a glass.
It sometimes presents prisms or columns of various size. These prisms
may have from three to seven sides, and are often quite regular. Many green-
stones are susceptible of a polish. It occurs in beds, more or less large, and
sometimes forms whole mountains.
Greenstone is common in the United States. When this rock breaks into
prismatic fragments, it forms a very useful building stone. Most of its varie-
ties, when heated red-hot, plunged into cold water, and pulverized, become a
good substitute for puzzolana in preparing water-proof mortar for the con-
struction of walls, cellars, docks, piers, &c. This rock has sometimes received
the appellation of trap, which seems to be a generic term, applied to those
stones which consist principally of hornblend.
SECTION VIII. — Sandstone, or Freestone.
Sandstone is composed, generally, of grains of quartz (see Granite), united
by a cement, which is never very abundant, and often, indeed, nearly or quite
invisible. These grains are sometimes scarcely distinguishable by the naked
eye, and sometimes their magnitude is equal to that of a nut or an egg.
24
PRACTICAL MASONRY.
The cement is variable in quantity, and may be calcareous or merely argil-
laceous or siliceous. When siliceous, the mineral much resembles quartz. The
texture of some sandstones is very close, while that of others is so loose and
porous as to permit the passage of water.
Some varieties are sufficiently hard to give fire with steel, while others are
friable, and may be reduced to powder even by the fingers ; this is often the
case with those sandstones whose cement is marly.
Its fracture is always granular or earthy ; in some instances it may, at the
same time, be splintery. Some sandstones have a slaty structure, arising from
scattered plates of mica, and have been called sandstone slate.
Its most common color is gray or grayish ; it is sometimes reddish, or reddish-
brown. In some cases the color is uniform, in others variegated.
Among the varieties are, —
1. Red Sandstone. The grains of this variety are usually coarse, and united
by an argillaceous cement, which is at the same time ferruginous ; hence the
dark reddish or reddish-brown color which it presents.
2. Variegated Sandstone. This presents a variety of colors ; as yellow, green,
brown, red, and white, which are usually arranged in stripes, or zones, either
straight or wavering. It has commonly a close texture and hne grain ; but it
very often embraces roundish masses of clay, which often fall out when ex-
posed to the weather, and diminish its value for the purposes of architecture.
3. White Sandstone. This includes many of the more common and valua-
ble varieties of sandstone. Its color is whitish-gray or gray, and generally uni-
form ; but sometimes it is marked with reddish spots. Its cement is often cal-
careous. It is well adapted for various uses in the arts.
Sandstone is, in general, more or less distinctly stratified. Its beds are very
often nearly or quite horizontal ; but sometimes, especially in the older varie-
ties, they are much inclined, or even vertical. Sometimes, also, when in the
vicinity of primitive mountains, its beds are thin, and much bent or waved.
Beds of sandstone are sometimes intersected with fissures perpendicular to the
direction of the strata, and hence fall into tabular masses, which are often very
large.
Sandstone is found in various parts of the United States, and is, in some
of its varieties, very useful , in the arts. It is frequently known by the name
of freestone. When sufficiently solid, it is employed as a building stone. In
most cases, it is of moderate hardness, and cuts equally well in all directions.
Some varieties naturally divide into prismatic masses. It is sometimes used
as millstones, for grinding meal, or for wearing down other minerals, prepar-
atory to a polish. These stones, when rapidly revolving, have been known
OF GNEISS.
25
to burst with a loud and dangerous explosion. When the texture is sufficiently
loose and porous, it is employed for filtering water. Some varieties are used for
whetstones.
Sandstone is used for buildings, in various parts of Europe. In Africa, the
Temple of Hermopolis is composed of enormous masses of this stone. In Amer-
ica, the Capitol at Washington is of the Potomac freestone or sandstone; likewise
the facade of St. Paul’s Church, in Boston.
SECTION IX. — Gneiss.
This rock, like granite, is composed of feldspar, quartz, and mica. But there
is in gneiss less feldspar and more mica, than in granite ; but even in this sub-
stance the feldspar appears in many cases to be the predominant ingredient. Its
structure is always more or less distinctly slaty, when viewed in the mass ; although
individual layers, composed chiefly of feldspar and quartz, may possess a granular
structure. The layers, whether straight or curved, are frequently thick ; but
often vary considerably in the same specimen; and when the mineral is broken
perpendicular to the direction of the strata, its fracture has commonly a striped
aspect. It splits easily in the direction of the strata, especially when a separation
is made in a layer of mica. When gneiss is broken in the direction of the strata,
the mica often seems more abundant than the other ingredients, but when seen on
the cross fracture, it obviously exists in less proportion than the feldspar or quartz.
The plates, or foliae, of mica, are usually arranged parallel to the direction of the
strata, and in some varieties are chiefly collected into thin parallel layers, separated
by those of feldspar and quartz. The grains of feldspar are often flattened in the
direction of the strata.
The feldspar is usually white, or gray, sometimes with a tinge of yellow or red.
The quartz is ordinarily grayish-white ; and the mica is often black, but some-
times gray.
The hardness of gneiss is variable ; and the feldspar and mica are subject to
the same changes as when they exist in granite.
Gneiss, like granite, never embraces any petrifactions, and is always a primitive
rock.
When gneiss occurs with granite, it usually lies immediately over the granite ;
or, if the strata be highly inclined, it appears rather to rest against the granite,
than to be incumbent upon it.
This rock, as has been intimated, assumes sometimes a granular structure, and
passes, by imperceptible shades, into granite.
4
26
PRACTICAL MASONRY.
Mountains composed of gneiss are seldom so steep as those of granite.
This rock is abundant in the United States. It is useful for many purposes,
in consequence of the facility with which it splits into masses of regular form.
SECTION X.— Mica-slate.
Mica-slate is essentially composed of mica and quartz (see Granite), which
are, in general, more or less intimately mingled ; but sometimes the two ingredi-
ents alternate in distinct layers. Although the proportions of mica-slate are varia-
ble, the mica usually predominates.
The quartz is most frequently grayish-white ; but the mica may be whitish, or
gray, bluish-gray, or greenish, brownish, deep blue, or nearly black.
Its structure is always distinctly slaty, more so than that of gneiss ; and its
masses are often very fissile. The layers are sometimes straight and sometimes
undulated. In some varieties the texture is very fine, and the foliae of mica so
small that they are scarcely discernible by the eye, unless their aggregation be
previously destroyed by heat.
This rock has often a very high lustre, when viewed by the reflected rays of
the sun. It is, however, subject to decomposition, by which its aspect is much
altered.
Mica-slate is a primitive rock ; but seldom appears in high, steep cliffs like
those of granite. When it forms hills, the summits are usually much rounded.
It abounds in ores, which exist both in beds and veins ; but more frequently in
beds. It is less abundant in the United States than gneiss. It is sometimes
split into tabular masses, and employed for many common purposes. It is
extremely useful in constructing the hearths and sides of furnaces for smelting
iron.
SECTION XL — Slate.
Slate is an argillaceous stone, characterized by easily splitting into large, thin,
and straight layers, or plates, which are sonorous when struck by a hard body. It
is dull, or has only a feeble lustre. Its colors are blackish -gray, or bluish-black,
bluish, or reddish-brown, or greenish, &c.
It belongs both to secondary and primary rocks. Its structure, en masse, is
tabular ; the small structure lamellar ; the cleavage of the laminae being parallel
with the tables.
Slate rocks vary in hardness, but they yield to the knife. They consist of an
OF SLATE.
27
intimate intermixture, in various proportions, of siliceous earth, alumine, and iron ;
and sometimes contain a portion of lime, magnesia, manganese, and bitumen.
Slate forms entire mountains, and sometimes distinct beds, alternating with other
rocks. It most frequently rests on granite, gneiss, and mica-slate.
As this substance forms the most light, elegant, and durable covering for
houses, and is, of course, of considerable value, it is rather surprising that so
much indifference prevails respecting the search for it, in those districts where
common slate, or clay-slate, abounds. We believe all the roof-slate quarries at
present worked are those which accident has discovered. This neglect is the
more remarkable, when we consider the great expense frequently incurred for
coal, a substance of less value in proportion to the weight.
All the best beds of roof-slate, it is believed, improve as they sink deeper into
the earth ; and few^, if any, are of a good quality near the surface, or are indeed
suitable for the purpose of roofing. There cannot be a doubt, that many beds of
state, which appear shattered and unfit for architectural use, would be found of
good quality a few yards under the surface ; for the best slate, in many quarries,
loses its property of splitting into thin laminae by exposure to the air.
Though the specific gravity of slate from different quarries is the same, yet all
the sorts are not capable of being split into an equal degree of thickness. It is
good slate which will split into laminae of one eighth of an inch in thickness. It
then weighs rather more than twenty-six ounces to a square foot, when applied
to the covering of a roof. In some instances, slate of a thinner quality is used,
where cheapness rather than durability is the principal object of the architect.
According to an estimate of Dr Watson, the relative weights of a covering of the
following different materials, for forty-two square yards of roof, are, —
Copper, - - 4 Cwt.
Fine Slate, - 26 “
Lead, - - 27 “
Coarse Slate, - 36 “
Tile, - - 54 “
Slate, to be of a good quality for building, besides possessing the property of
splitting into thin laminae, should resist the absorption of water ; to prove whicn,
it should be kept some time immersed in water, being weighed before and after
the immersion, wiping the surface dry ; it is obvious that the slate which gains
the least weight by this process is the least absorbent. It should resist the pro-
cess of natural decomposition by air and moisture ; this depends on its chemical
composition and compactness, and is shown by its resisting the process of vege-
tation. That slate which is most liable to decay, will be the soonest covered
with lichens, mosses, &c. The hardness of slate principally arises from the silex
28
PRACTICAL MASONRY.
it contains, which is of all earths the least favorable to vegetation. Those slates
which are the hardest when first taken from the quarry, and which have the
least specific gravity, are to be preferred ; for the increase in weight is owing to
the presence of iron, to which slate and other stones, in some measure, owe
their decomposition ; while alumine renders them soft and absorbent.
Slate is so durable, in some cases, as to have been known to continue sound
and good for centuries. However, unless it should be brought from a quarry of
well reputed goodness, it is necessary to try its properties, which may be done by
striking the slate sharply against a large stone, and if it produce a complete sound
it is a mark of goodness ; but if, in hewing, it does not shatter before the edge of
the instrument commonly used for that purpose, the criterion is decisive. The
goodness of slate may be farther estimated by its color ; the deep blue-black
kind is apt to imbibe moisture, but the lighter blue is always impenetrable. The
touch, also, in some degree, may be a good guide, for a good firm stone feels
somewhat hard and rough, whereas an open slate feels very smooth, and, as it
were, greasy. Another method of trying the goodness of slate is, to place the
slatestone lengthwise and perpendicularly in a tub of water, about half a foot
deep, care being taken that the upper or unimmersed part of the slate be not
accidentally wetted by the hand, or otherwise ; let it remain in this state twenty -
four hours ; and, if good and firm stone, it will not draw water more than half an
inch above the surface of the water, and that, perhaps, at the edges only, those
parts having been a little loosened in hewing ; but a spongy, defective stone will
draw water to the very top.
Roof-slate is found in Pennsylvania, on the banks of the Delaware, about seven-
ty-five miles from Philadelphia, of a good quality. In New York, at New Paltz,
Ulster county ; and at Rhinebeck, Duchess county. In Dummerston, Ver-
mont, it exists in strata nearly vertical ; it is also found at Rockingham and Cas-
tleton, where it is of a pale red. It exists in Maine, at Waterville and Winslow,
on the Kennebec River.
Extensive quarries of slate, of a good quality, are worked near Bangor, Eng-
land ; this slate is exported in large quantities to various parts of the world.
It may be noticed, that, in laying of this material, a bushel and a half of lime,
and three bushels of fresh-water sand, will be sufficient for a square of work; but
if it be pin-plastered, it will take about as much more ; but good slate, well laid
and plastered to the pin, will lie a hundred years, and on good timber a much
longer time. It has been common to lay the slates dry, or on moss only, but
they are much better when laid with plaster.
OF SOAPSTONE, OR STEATITE.
29
SECTION XII. — Soapstone, or Steatite.
All the varieties of soapstone are so soft, that they may be cut by a knife,
and, in most cases, scratched by the finger-nail. Its powder and surface are soft,
and more or less unctuous to the touch. It is seldom translucent, except at the
edges. Its fracture is in general splintery, earthy, or slaty, with little or no
lustre.
By exposure to the heat it becomes harder, but is almost infusible by the blow-
pipe. It appears to be essentially composed of silex, magnesia, and perhaps
alumine.
The common variety is usually solid, with a compact texture ; its surface is
often like soap to the touch ; but sometimes it is found of a considerable degree
of hardness.
Its color is usually gray or white, seldom pure, but occasionally mixed with
yellow, green, or red, and is sometimes a pale yellow, reddish, or green of different
shades. The colors sometimes appear in spots, veins, &c.
Its specific gravity usually lies between 2.58 and 2.79. When solid it is
somewhat difficult to break. Before the blow-pipe it whitens and becomes hard,
and is with difficulty reduced into a whitish paste or enamel, often, however, only
at the extremity of the fragment. Some specimens have yielded by analyzation,
silex 64 parts, magnesia 22, alumine 3, water 5, iron and manganese 5.
Soapstone occurs in masses, or veins, or small beds, in primitive and transition
rocks, more particularly in serpentine. It is sometimes mixed with talc, mica,
quartz, and asbestos ; or is found incrusted with other minerals.
This stone is not uncommon. It is found in various parts of the United States.
Among the best quarries for fire-proof stone is that of Francestown, New Hamp-
shire. It occurs, also, in Connecticut, near New Haven, and at Oxford, Grafton,
and Athens, in Vermont.
Soapstone, on account of its softness, is wrought with the same tools as wood.
It receives a tolerable polish, and is sometimes used in building, but is not always
durable. It is, however, of great importance in the construction of fire-places and
stoves, and is extensively used for this purpose. Slabs of good soapstone, when
not exposed to mechanical injury, frequently last eight or ten years, under the
influence of a common fire on one side, and of cold air on the other. It grows
harder in the fire, but does not readily, crack, nor change its dimensions suffi-
ciently to affect its usefulness. Owing to the facility with which it is wrought, its
joints may be made sufficiently tight without dependence on cement.
30
PRACTICAL MASONRY.
It is often wrought into various utensils by turning, and is advantageously
employed for aqueducts. It has been found to be one of the best materials for
• counteracting friction in machinery, for which purpose it is used in powder, mixed
with oil. It has also been employed for the purpose of engraving. By being
easily cut, when soft, it may be made to assume any desired form, and afterwards
rendered hard by heat ; it then becomes susceptible of a polish, and may be
variously colored by metallic solutions.
SECTION XIII. — Gypsum.
Gypsum is a term applied in its restricted sense to those varieties of sulphate
of lime which have a fibrous or granular structure, being the result of confused
crystallization, and to those, whose texture is compact, or earthy. It is a sub-
stance that is interesting on account of its uses in agriculture and the arts. Its
colors are commonly white or gray, sometimes shaded with yellow, red, or vari-
ously mingled.
It occurs in compact masses, sometimes granular, and sometimes in parallel
fibres. Though sometimes coarse, the fibres are often fine and delicate, glisten-
ing with a pearly satin lustre. Its fracture is foliated, sometimes splintery ; it is
generally translucent, often in amorphous masses ; but not unfrequently crystal-
lized. It is less hard than carbonate of lime. Its specific gravity usually lies
between 2.26 and 2.31. By the blow-pipe it may be melted, though not very
easily, into a white enamel, which shortly falls into a powder. It does not effer-
vesce with acids, if it be pure sulphate of lime. It is soluble in about five hun-
dred times its weight of water. It does not bum to lime.
It is composed of 32 parts of lime, 46 of sulphuric acid, and 22 parts of water ;
but it is often contaminated with small quantities of carbonate of lime, alumine,
silex, and oxyd of iron. Some varieties are employed in sculpture and architec-
ture under the name of alabaster ; the same name is also given to some varieties
of carbonate of lime.
The plaster-stone, or plaster of Paris, often contains foreign ingredients, which,
in many instances, improve it as a cement.
This substance is found in abundance in many places, and has been extensively
used for manure in dressing land, and appears to be useful in both clayey and
sandy soils. It is also employed in the imitative and ornamental arts. Alabaster,
both of the sulphate and carbonate kinds, has been used for the same purposes
as marble in architecture and statuary ; and, being less hard, it is more easily
wrought ; but is less durable and less valuable than marble. Gypsum, when
OF PUZZOLANA.
31
deprived of its water of crystallization by burning or drying, constitutes plaster,
and this plaster, when mixed with a certain quantity of quicklime, forms a good
cement. The plaster of Paris often contains, in its natural state, a sufficient
quantity of carbonate of lime to constitute a good cement after calcination.
The finer kinds of plaster, being reduced to powder, and mixed with water,
have the property of becoming hard in a few minutes, and of receiving accu-
rately the impressions of the most delicate models. It is extensively employed in
stucco work, and in plastering rooms. It furnishes a delicate, white, and smooth
material for architectural models, impressions of seals, &.c. ; and in the art of
stereotyping it is indispensable. In stucco, various colors, previously ground in
water, may be introduced. All these works, when dry, are susceptible of a
polish.
The Temple of Fortune, called Seja, appears to have been built with some
variety of sulphate of lime. It had no windows, but transmitted a mild light
through its walls.
SECTION XIV. — PvzzoLANA.
This substance is of volcanic origin. It usually occurs in small fragments, or
friable masses, which have a dull, earthy aspect and fracture, and seems to
have been baked. Its solidity does not exceed that of chalk. It is seldom
tumefied, and its pores are neither large or numerous. Its colors are gray or
whitish, reddish or nearly black.
By exposure to the heat it melts into a black slag. A variety examined by
Bergaman yielded 55 to 60 parts of silex, 19 to 20 of alumine, 15 to 20 of iron,
and 5 to 6 parts of lime. It often contains distinct particles of pumice, quartz,
and scoria.
This substance is extremely useful in the preparation of a mortar which hardens
quickly, even under water. When thus employed it is mixed with a small pro-
portion of lime, perhaps one third. It has been supposed that the rapid indura-
tion of this mortar arises from the very low oxydation of the iron. If the mortar
be a long time exposed to the air, previous to its use, it will not harden. The
best puzzolana is said to occur in old currents of lava ; but when too earthy it
loses its peculiar properties. That which comes from Naples is generally gray.
32
PRACTICAL MASONRY.
SECTION XV. — Tras, or Terras.
The nature of this is similar to some varieties of puzzolana ; and it contains
nearly the same principles, but with a greater proportion of lime. Its hardness
is, however, much greater than that of puzzolana. Its color is brownish or yel-
lowish ; and its fracture earthy and dull. It has been found chiefly near Ander-
nach, in the vicinity of the Rhine.
It is said to be decomposed basalt. It forms a durable water-cement when
combined with lime. It is the material which has been principally employed by
the Dutch, whose aquatic structures probably exceed those of any other nation
in Europe. Terras mortar, though very durable in water, is inferior to the more
common kinds, when exposed to the open air.
SECTION XVI. — Quarrying.
The common methods of working and managing different sorts of quarries are
in general pretty well understood by such quarrymen as are constantly employed
in the business. The materials are indicated by the appearance of the surface of
the earth, the nature of the substances in the vicinity, or by digging down and
opening the ground by spades and other tools, or by boring with an auger made
for the purpose.
The great value to mankind of such materials as coal, iron ores, &c., as well
as of building materials, should induce proprietors of land to cause a more diligent
and scientific search for these hidden treasures than has been hitherto practised
in this country. It may also be suggested, that it would be highly beneficial and
advantageous, if mineralogists and those who have an acquaintance with such
substances were to turn their attention towards the appearances and accompani-
ments which point out such useful concealed matters ; as it might greatly facili-
tate the search for them, and frequently lead fortuitously to their discovery. In
searching for most sorts of mineral substances, coals, and some other matters, the
use of the borer is almost constantly resorted to ; but with regard to limestone,
freestone, granite, &.C., digging down into the earth is the mode commonly em-
ployed in the first instance, in consequence of such substances being obviously
present in sufficient quantities to be wrought with advantage.
When it has been ascertained that the material exists in sufficient quantity to
OF QUARRYING.
33
warrant the working of the quarry, much time and expense will be saved by pro-
ceeding in a correct manner in the first opening of it.
Instead of beginning to dig at the top, by which means the progress of the
workmen will soon be impeded by accumulating rubbish, or the rushing in of
water, it would be far preferable to commence on one side of the elevation which
contains the material, having previously ascertained which way the rocks incline
or dip, and gradually approach the quarry on this side ; clearing away the dirt
and superincumbent substances as low down as the nature of the ground will
admit. In this manner, the mouths or openings of the quarries may be easily
kept free, and the water carried off ; at the same time, the materials may be op-
erated upon and removed with the greatest facility. If the nature of the situa-
tion admits of the opening of a quarry in this manner, the more convenient method
of working it is by gradations or steps. That is, the stone is first taken from the
top to an uniform depth, for a considerable distance back ; then another stratum
or layer is removed, till it approaches within some distance of the first, when a
third is begun, and so on ; so that the quarry presents the appearance of steps,
or horizontal planes one above the other. This method affords facilities for re-
moving the stone or materials, without the aid of expensive machinery.
There is often a great difference in the quality of the material in the same
quarry. Those portions which are nearest to the surface are sometimes mixed
with foreign ingredients, that impair their value or render them useless.
The stones are obtained of suitable dimensions by blasting, by splitting with
iron wedges set in a direct line, and driven with much force by a sledge or ham-
mer. Advantage is often taken of natural fissures which are in straight lines, and
often at right angles.
Granite, and the stones related to it, although of great hardness, will split very
straight, by means of wedges. The pieces are afterwards wrought into the form
to be used, either at the quarry, which diminishes the expense of transportation,
or removed in a rough state, and thus used in building ; or finished, as may be
deemed expedient.
In working granite and materials of a similar nature, it is first lined, or marked
into the form desired. The workman then forms the edge all round by means
of a chisel and hammer, making it smooth and straight to the depth of one or two
inches ; he afterwards breaks off the larger portions with a hammer made in a
peculiar form, and kept sharp ; with this instrument he continues to take off the
inequalities of the surface, till it has the requisite smoothness.
Sandstone, freestone, and materials of the like nature, being less hard than
granite, are more easily wrought by a similar process. Some of them admit of a
considerable degree of polish.
5
34
PRACTICAL MASONRY.
Marble and soapstone are taken from the quarries in large masses, and after-
wards sawed, either by hand, or in mills constructed for the purpose, and then
polished. (See Marble and Soapstoiie.) Slate, in some instances, is obtained
by blasting. It is sometimes dug out by one set of men, split by another, and
formed into slates by a third ; for which purposes, flat crowbars, slate-knives,
and axes are employed. It is often divided into three sorts, as firsts, seconds,
and thirds, which vary in quality and price.
Sand and gravel are mostly dug out from the sides of banks, and other places ;
and but rarely obtained by sinking the quarries into the more level parts of the
ground, though this method is sometimes practised, d'he materials are common-
ly raised, simply by digging with spades ; and thrown into carts, in many cases,
from the quarries or pits themselves.
The removal of materials from quarries is effected by means of inclined planes,
of railways, or by various machines constructed for the purpose, such as the
windlass, the pulley, &c., adapted in each instance to the situation of the quarry,
and the circumstances of the case.
The Quincy stones are raised from their beds by the means of a windlass
worked by a horse, and received upon cars, which run upon inclined railways,
within a few feet of the quarry ; from thence they are conveyed to the sea on a
railway, and transported in various directions. By the descent of a loaded car
on the inclined railway at the quarry, an empty car is drawn up.
' The greatest difficulty incident to working quarries is that of draining, and
freeing their bottom parts from injurious water ; so that they may be in a fit state
to be wrought with ease and advantage.
The most usual remedies resorted to in this difficulty are pumps worked by
wind, by horse, steam, or other powers ; but these often prove ineffectual in re-
moving the water completely, and new quarries are opened near the old ones.
But an attention to certain principles, in regard to the nature of the soil and the
courses of subterraneous waters, may often lead to more cheap, expeditious, and
effectual remedies.
It is now well understood, that most springs and subterraneous collections of
Avater are formed and supplied from such grounds as lie higher than that of the
places where the waters are met with, which, in consequence of their being of an
open and porous nature, admit the rain and other sorts of moisture to filtrate and
pass freely through them. These waters descend to great depths before they
become impeded by some sort of impenetrable stratum, or layer of a solid or siony
nature, as clay, or compact rock. It may happen, in sinking quarries, that beds
of quicksand may be met with, which are so full of water, that to penetrate
through them will be very difficult ; and from a knowledge that the water pro-
OF QUARRYING.
35
ceeds from the porous ground that lies above them, it may be practicable to in-
tercept and cut off the greater part of it before it reaches the sand-beds in the
quarries, by the means of boring into and tapping the water at the tails of the
banks of this nature, provided that the ground declines lower than the place
where the sand is found in the quarries, which may be done at a trifling expense
in comparison to the common remedies.
But in order to accomplish this intention, it will be necessary, in ascending from
the quarry, to ascertain if, at the place higher on the declivity, any porous stratum,
bed of rock, sand, or gravel, tails out, which may convey the water contained in
it to the sand-bed, which is below in the works ; and where any such is found,
to cut and bore into it, in such a manner as to form a drain, that is capable of
conveying off the water, which would otherwise have descended into the quarry.
But although this part of the business may have been accomplished, and the
supply of water from the higher ground entirely cut otf, a sufficient quantity to
injure and inconvenience the working may yet continue to drain from the sides of
the sand-beds, though they should happen to dip towards the lower ground ; in
which cases, however, this water may be drawn off readily to some particular
point.
In order to effect this, it should be ascertained at what particular place in the
low ground the sand terminates, or tails out, which is the best accomplished by
means of proper levelling ; and if there should be any appearance, in this place,
of the water’s having a natural outlet, it may, by making it into a deep drain,
cause the water effectually to be drawn off. Where, however, there happens to
be a deep, impervious layer of clay, or other matter of a similar nature, placed
above or upon the termination or tail of the sand, the drain need only be cut
down to it, or a little way into it, as by means of boring through it a ready and
easy passage may be given to the whole of the water contained in the sand-bed
or porous stratum.
It is of material importance to lay dry all such grounds as are situated higher,
but contiguous to quarries, for the above-stated reasons ; and it may in general
be accomplished with but little difficulty and expense, by adopting the same
principles and the same means.
This is the mode that is to be pursued in preventing the effects of the water,
or cutting it off, when met with in sinking quarries. It proceeds on the principle
of the dipping position of the strata, with I he natural inclination of the land.
It frequently happens that a body of the same stone, which is of a close and
compact nature, is found lying under one which has a more open and porous
texture, with fissures and cracks in it, that are admissible of water, in the upper
body or layer, in such a manner that none can pass through it to the inferior, or
36
PRACTICAL MASONRY.
Still deeper, open stratum or bed ; and on sinking or cutting through this compact
bed, another layer is met with, which is of so porous a nature as to admit the re-
ception of any water that may come upon it. And sometimes a bed of gravel or
sand is found under that of close stone, which, being capable of absorbing any
water that may come upon it, is far better suited for the purpose of clearing the
upper bed of stone from water than the stratum of open stone itself. Therefore,
when this is ascertained to be the case, and the water is kept up by the second
bed of stone, so as to be injurious to the working of the upper bed, and which
will be equally so in working the second, the work may be greatly freed by bor-
ing through the close bed of stone, and letting the water down into the more
porous one below, or into a stratum of dry sand or gravel, should there be such a
one underneath it. But, instead of boring, the sinking of small pits through the
close stone is a more effectual way of letting down the water.
In all such cases as these, boring or sinking pits through the solid stratum into
a porous substance or layer underneath is the most advisable, and, at the same
time, the least expensive, method that can be pursued.
OF THE WEIGHT OF STONE.
37
TABLE.
The following table shows the weight of granite stone, in pounds and hundredths, both in a cubi-
cal and cylindrical form ; the dimensions being given. The first column of figures denotes a piece
of stone to be 1,2,3, &c., inches square, or in diameter; each piece being 12 inches in length.
Columns two and three are the mean weight of common stone ; four and five, the weight of the
Quincy stone ; six and seven, the weight of a species of coarse granite, found at Sandy Bay, in
Massachusetts.
MEAN WEIGHT OF STONE IN GENERAL.
QUINCV GRANITE.
S.VNDV BAY
GRANITE.
Square.
C>lindric.
Siiuare.
Cylindric.
Square.
Cylindric.
.
" 1
1.07
.86
1.16
.95
1.17
.95
to
2
4.33
3.45
4.65
3 80
4.68
3.80
-2
3
9.70
7.75
10.44
8.55
10 53
8.56
' o
4
17.33
13.80
18.56
15.20
18.72
15.21
5
27.00
21.50
29.00
i o
29.22
23.77
6
38.10
31.00
41.76
34.20
42. 12
34.23
7
52.67
42.00
55.88
46.55
57.33
T4.59
1 »
8
69.00
55.00
74.24
60.80
74.88
60.86
! 1
9
86.67
69.65
83.96
76.95
94.77
77.03
5
10
107.33
86.00
116.00
95.00
117.00
95.10
11
130.00
104.00
140..36
114.95
141.57
115.07
1 ^
1
12
-
155.00
124.00
167.04
136.80
168.48
136.94
1 tb
' 1
5.35
4.30
5.80
4.75
5.85
4.75
1 o
2
23.65
17.25
23.20
19 00
23.40
19.40
3
48.50
38.75
52.20
42.75
52.65
42.80
1 o
o
4
86.65
69.00
92.80
76.00
93.60
75.05
5
135.00
107.. 50
145.00
118.75
146.10
118.85
6
190.50
155.00
200.80
171.00
210.00
171.15
1 t ^
7
263.35
310.00
379.20
232.75
286.65
222.95
8
345.00
275.00
1 371.20
304.00
374.40
304.30
o
9
433.35
318.00
419.80
38475
1 473.85
385.15
1 c
10
536.65
430.00
580.00
475 00
1 585.00
475.50
1
11
650.00
520.00
701.80
574.75
j 707.85
575.35
; ”
775.00
620.00
835.20
680 00
! 842.10
1
684 70
' 1
10.70
8.60
11.60
9.50
11.70
9.50
j «
2
43 30
34..50
46.40
38.00
56.80
38.00
O
3
97.70
77.50
104.40
85.50
10530
85.60
o
4
173.30
138.00
185.60
152.00
187.20
152.10
5
270.00
215.00
290.00
237.50
292.20
237.70
o
6
381.00
310.00
417.60
342.00
i 421.20
342.30
1 cS
7
526.70
420.00
558.40
465.50
, 573.30
445.90
8
690.00
550.00
742.40
608.00
1 748.80
608.60
o
9
866.70
696.00
839.60
769.50
1 947.70
770.30
10
1073.00
860.00
1160.00
950.00
i 1 170.00
951.00
i 0?
11
1.300.00
1040.00
1403.00
1149.00
1415.70
11.50.70
i ^
.12
1550.50
1240.00
1670.40
1368.00
1684.80
1369.40
38
PRACTICAL MASONRY.
Mean Weight of a Cubic Foot of Stone, and the Weight it w sustain with Safety.
Granite.
Mean Weight.
Weight it will sustain.
Sandy Bay Stone,
148.48 lbs.
197,000 lbs.
Quincy do.
167.04 “
156,000 “
Concord do.
159.00 “
149,000 “
Frankfort do.
162.00 “
148,000 “
Marble.
White New York,
173 lbs.
85,000 lbs.
New Haven Variegated,
175 “
89,000 “
Pennsylvania Dove,
170 “
86,000 “
Thomaston Blue,
179 “
90,000 “
Vermont Dove,
168 “
86,000 “
Sandstone or Freestone.
Connecticut,
164 lbs.
118,000 lbs.
North River,
156 “
108,000 “
Potomac,
153 “
98,000 “
TABLE OF CYLINDRICAL MEASURES.
Designed for the computation of the contents of lead pipes, from one inch diameter to three and
upwards ; also, cisterns of ten feet diameter and under ; the quantity and weight of water in
pumps, suction pipes, &c., from one inch diameter and upwards.
Inches Diame-
ter.
Cubic feet and parts.
Ale gallons and parts.
Wine gallons and
parts.
Weight of water, in lbs.
and parts.
Dry bushels and parts.
1
.0055
.033
.04
.34
.0044
2
.0218
.134
.16
1.36
.0175
3
.0491
.301
.37
3.06
.0394
4
.0873
.534
.65
5.45
.0700
5
.136
.835
1.02
8.52
.110
6
.196
1.20
1.47
12.27
.158
7
.267
1.64
2.00
16.70
.215
8
.349
2.14
2.61
21.82
.281
9
.442
2.71
3.30
27.61
.355
10
.545
3.34
4.08
34.09
.438
11
.660
4.04
4.94
41.25
.530
12
.785
4.81
5.88
49.09
.631
24
3.14
19.25
23.52
196.36
2.521
36
7.07
43.30
52.92
441.79
5.68
48
12.57
77.00
94.08
785.44
10.10
50
13.64
83.55
102.00
852.21
11.00
60
19.64
120.30
146.88
1227.19
15.78
72
28.28
173.20
211.51
1767.15
22.72
84
38.49
235.81
287.88
2405.28
30.92
96
50.27
308.00
376.01
3141.59
40.39
108
63.62
389.79
475.89 t
3976.08
51.12
120
78.54
481.25
587.52
4903.74
63.11
N. B. If the diameter should fall between any of the numbers in the first column, the mean
proportional contents may be found by adding the two contents between which it falls, and dividing
OF THE WEIGHT OF IRON.
39
by two. Suppose it falls between 108 and 120 of the diameters, required the wine gallons in 114
inches, or 9 feet 6 inches diameter, which falls between 587.52
and 475.89
2) 1063.41
Answer, 531.70|
Or if between 60 and 72, say 64 inches, or 5 feet 4 inches ; one third of 12 is 4 ; then required
the cubic feet and parts.
28.28
Subtract 19.64
Divide by 3) 8.64
Add 19.64
Answer, 22.52
Any depth may be found, by multiplying by the depth any of the numbers in the contents ; as, re-
quired the number of ale gallons in 24 inches diameter, at 6 feet deep. 19.25 X 6 — 115.50, Ans.
A TABLE
For the computation of the weight of wrought iron of different dimensions, from ^ of an inch to
5 inches square ; also, round, from ^ of an inch to 5 inches diameter. The third and fourth columns
for flat bars, from 1^ to 6 inches wide, from ^ to 5 inches thick ; each dimension estimated at one
foot in length.
Square Bars.
!
Round Iron.
Flat Bars.
In.
8lhs.
lbs.
OZ.
dr. 1
In.
Sths.
lbs.
OZ.
dr.
In. Sths.
lbs.
OZ.
dr.
In. Sths.
lbs.
OZ.
dr.
1
0
1
12 i
1
0
0
14
l|Xl
0
4
6
2|X2
2
3
0
2
0
3
8 1
2
0
1
12
2
0
8
12
3
3
4
8
3
0
7
14 !
3
0
7
0
3
1
10
4
4
4
6
0
4
0
14
0 '
4
0
11
0
4
2
3
0
5
5
7
8
5
1
5
14
5
1
1
3
5
2
11
12
6
6
9
0
6
1
15
8
6
1
8
12
HX2
1
5
0
7
7
10
8
7
2
10
14
7
2
1
11
3
1
15
8
8
8
12
0
1
0
3
8
0
1
0
2
12
0
4
2
11
0
2|X3
3
9
12
1
4
6
14
1
3
7
11
5
3
4
8
4
4
13
0
2
5
7
8
2
4
4
12
1|X2
1
8
8
5
6
0
4
3
6
9
14
3
5
3
3
3
2
4
12
6
7
3
8
4
7
14
0
4
6
3
0
4
3
1
0
7
9
10
0
5
9
3
14
5
7
4
3
5
3
13
4
3x3
3
15
0
6
10
11
8
6
8
6
12
6
4
9
8
4
5
4
0
7
12
4
14
7
9
10
11
7
5
5
12
5
6
9
0
2
0
14
0
0
2
0
11
0
0
8
6
2
0
4x3
5
4
0
1
15
12
14
1
12
6
11
2 X2
1
12
0
4
7
0
0
2
17
11
8
2
13
14
12
3
2
10
0
5
8
12
0
4
21
14
0
3
15
8
3
4
3
8
0
8
14
0
0
6
26
7
8
4
17
3
0
5
4
6
0
5x3
6
9
0
3
0
34
0
0
5
18
15
3
6
5
4
0
4
8
12
0
2
36
15
8
6
20
12
12
7
6
2
0
5
10
15
0
4
42
14
0
7
22
11
11
8
7
0
0
6
13
2
0
6
49
3
8
3
0
24
12
0
2|X2
1
15
8
6X3
7
14
0
4
0
54
0
0
4
0
44
0
0
3
2
15
4
4
10
8
0
2
63
2
8
2
49
11
12
4
3
15
0
5
13
2
0
4
70
14
0
1 5
0
68
12
0
5
4
14
12
6
78
15
8
1
1
5
0
87
8
0
40
PRACTICAL MASONRY.
RULES
FOR MEASURING HAMMERED GRANITE STONE,
ADOPTED APRIL, 1829.
PREAMBLE.
To prevent misunderstanding between the stonecutters, the masons, and their employers, in
relation to the admeasurement of hammered granite stone, it was deemed expedient that a meet-
ing be called of those engaged in the business, to endeavour to agree upon some uniform system,
that shall be equally intelligible to all parties ; said meeting was held in March last, when a com-
mittee of eleven persons was chosen, to take the subject into consideration, and report at a subse-
quent meeting. At a meeting in April, said committee reported, that they had attended to the
duty assigned them, and, after mature deliberation, have agreed on the following rules, which, if
adopted, will, in their opinion, greatly promote the interest as well as the harmony of all concerned
in the business, whether purchaser or vender ; at which meeting said rules were adopted by the
unanimous vote of all present, who then affixed their signatures to the same, since which others
have subscribed their names.
Boston, May 17, 1829.
RULES.
Section 1. Ashlar Stones are to be measured on their fronts, quoin-heads, and reveals
against doors, windows, and recesses.
Sect. 2. Headers or binders, that make the thickness of the wall, are to be measured as ash-
lar-work, adding their beds, or builds.
Sect. 3. Double-headed Quoins, not less than nine inches each head, are to be measured as
ashlar-work, adding their beds, or builds.
Sect. 4. Window-caps, for ashlar-work, are to be measured on their fronts, under sides that
show, and reveals.
Sect. 5. Window-sills, for ashlar- work, are to be measured on their tops and fronts, the
whole thickness of their rise, and half their under sides.
Sect. 6. Belt Stones, for ashlar or brick-work, from seven to nine inches rise, and the usual
thickness of ashlar-work, are to be cast at the rate of a superficial foot to each foot in length.
Sect. 7. Arch Stones, in ashlar- work, are to be measured their extreme lengths by their ex-
treme widths, adding the returns and reveals.
Sect. 8. Ashlar Stones, for pediments or gable ends of buildings, and other similar purposes,
are to be measured their extreme lengths by their extreme widths.
Sect. 9. Plinths are to be measured on all parts that show, and half the rough-hammered
parts.
Sect. 10. Pilasters are to be measured on their fronts, returns, and reveals.
RULES FOR MEASURING HAMMERED GRANITE.
41
Sect. 11. Imposts are to be measured on their fronts, ends, and beds, or builds.
Sect. 12. Posts or Caps are to be measured on four sides, and the ends of caps that show.
Sect. 13. Posts in or out of square are to be measured on four sides, squaring from their ex-
treme points.
Sect. 14. Door-sills, under posts, are to be measured on their tops, fronts, and ends, and
half the parts hammered under the ends.
Sect. 15. Window-sills, between posts, are to be measured on their tops, under sides, and
their whole rise.
Sect. 16. Arch Caps and Blocks, that make the thickness of the wall, are to be measured on
four sides, the extreme lengths by their extreme widths.
Sect. 17. Belt Stones, that make the thickness of the wall, are to be measured on their
fronts, beds, and builds, and ends that show.
Sect. 18. Courses of Stones, that make the thickness of the wall, are to be measured on
their fronts, beds, and builds.
Sect. 19. Door-steps are to be measured on their tops, fronts, and laps, and the ends that
show, which ends are to be measured at the rate of a superficial foot to each foot on the width.
Sect. 20. Returns for steps, from six to ten inches rise, are to be measured at the rate of a
superficial foot to each foot in length.
Sect. 21. Platform Stones are to be measured as steps; when two or more are required,
half the edges for joints are to be added.
Sect. 22. Spiral Steps are to be measured their e.xtreme length by their extreme width, rise,
and laps, and ends that show'.
Sect. 23. Fence Stones are to be measured on their fronts, tops, and inside, where hammered,
and ends that show.
Sect. 24. Posts, that stand in the ground, are to be measured on four sides and tops, and half
measurement of the rough parts in the ground, according to the dimensions of the hammered parts.
Sect. 25. Cellar-door Curbs are to be measured on their tops and inside, or rise, the whole
length of each stone ; the rabbets are to be measured the length of each stone by the running foot.
Sect. 26. Cellar-w'Indow Curbs are furnished by the piece.
Sect. 27. Well Curbs are to be measured on the outside and tops, where hammered with
the jogs and corresponding ends.
Sect. 28. Sesspool Curbs are to be measured as Cellar-door Curbs.
Sect. 29. Gutter Stones are to be measured on the top side by the superficial foot ; Cutting
Gutters to be charged extra.
Sect. 30. Edge Stones are to be measured by the running foot, double measure when circular.
Sect. 31. Cutting Scrools, Jogs, Rabbets, Grooves, Gutters, and Drilling Holes are
extra work, and do not add to or diminish from the measurement of the work.
Sect. 32. Vault Stones are to be measured on three or four sides, as may be hammered, and
the ends that show. Floor and Ceiling Stones, more than nine inches in thickness, are to be meas-
ured on one side and two edges, and the ends that show ; when nine inches or less thickness, on one
side and ends that show.
Sect. 33. All Stones not included in the foregoing specifications, on account of their irregular
form or unfrequent use, should be measured as nearly as possible according to the rules applying
to those which resemble them.
Sect. 34. Those which differ in all respects must be furnished by the piece.
Sect. 35. The two foregoing observations apply to Ornamental Work, the parts of which are
6
42
PRACTICAL MASONRY.
so minute, and generally of such complicated forms, that no system of rules sufficiently short and
comprehensive can with any utility be adopted ; with regard, however, to two or three parts of
Ornamental Work, in common use, it may be well to state, that Cornice is usually furnished by
the running foot ; Bases, Columns, and Capitals, by the piece.
Sect. 36. All Circular Work to be charged extra, and the mode of measurement should be
agreed upon at the time said work is contracted for.
William Austin,
Gridley Bryant,
Benjamin Blaney,
Jacob Bacon,
William Crehore,
Samuel Currier,
Levi Cook,
Conrad C. Carleton,
James C. Ewer, Jr.,
George H. Ewer,
Joseph Glass,
Ephraim Harrington,
Thomas Hollis,
Charles G. Hall,
Samuel R. Johnson,
Nathaniel Jewett,
Sewall Kendall,
Allen Litchfield, Jr.,
Ward Litchfield,
Francis Lawrence,
James McAllaster,
Caleb Metcalf,
Samuel Marden,
Luther Munn,
Jonathan Newcomb,
Cushing Nichols,
Alexander Parris,
James Page,
William Packard,
Lot Pool,
Joseph Richards,
John Redman,
Wyatt Richards,
Alanson Rice,
Edward Shaw,
Zephaniah Sampson,
Franklin Sawyer,
Asa Swallow,
James S. Savage,
Amos C. Sanborn,
Job Turner,
Joseph Tilden,
Charles Wells,
William Wood,
Mordecai L. Wallis,
Richard Witherell,
Henry Wood,
Jeremiah Wetherbee,
Salmon Washburn.
OF CLAY
43
CHAPTER II.
SECTION I. — Clay.
The substances included under this term are mixtures of silex, or the ingre-
dient of the common gun-flint and alumine ; they sometimes contain other earths,
or metallic oxyds, by the latter of which some varieties are highly colored.
Their hardness is never great ; they are easily cut by a knife, may in general be
polished by friction with the finger-nail, and are usually soft to the touch. When
immersed in water they crumble more or less readily, and become minutely
divided. Many clays, when moistened, yield a peculiar odor, called argillaceous ;
but this quality appears to be owing to the presence of metallic oxyds, as per-
fectly pure clays do not possess it.
The substances which are properly termed clays may, by a due degree of
moisture and proper management, be converted into a paste more or less tena-
cious and ductile, which constitutes the basis of several kinds of pottery. It
possesses a greater or less degree of unctuosity, and is capable of assuming
various forms without breaking. This argillaceous paste, when dried, becomes
in some degree hard and solid, and, by exposure to a sufficient degree of heat,
may be made to assume a stony hardness.
Clays have a strong affinity for water; hence the avidity with which they
imbibe it ; hence, also, they adhere more or less to the tongue or lips.
Clay, when composed of only silex and alumine, in any proportions, is infusible
in a furnace, and even when somewhat impure it resists a degree of heat without
melting. But the presence of other earths, particularly of lime, or of a large
quantity of oxyd of iron with a little lime, renders it fusible. By exposure to
heat it diminishes in bulk, and loses somewhat of its weight by the escape of
water.
Although clay is essentially composed of silex and alumine, these ingredients
exist in various proportions. In most cases silex predominates, being in the
proportion of two, three, or even four parts to one of alumine ; sometimes the pro-
portions are nearly equal, and in some cases the alumine predominates. The
power of alumine to impress its character on the compound, although present in
less proportion than the silex, probably arises from a greater minuteness of its
particles.
The color of clay may proceed from oxyd of iron, or from some bituminous or
vegetable matter. Hence some colored clays, when exposed to heat, become
44
PRACTICAL MASONRY.
white by the destruction of their combustible ingredients, while others suffer
merely a change of color, by the action of oxygen on the iron. The purer clays
are white or gray, and suffer little or no change by the action of fire.
The varieties of clay are numerous ; the purest kinds are extensively used in
the manufacture of porcelain ware ; and those that are less pure are burnt into
stone ware and bricks.
The common clays may be divided, in regard to their utility, into three classes,
the Unctuous, Meagre, and Calcareous.
The unctuous contains, in general, more alumine than the meagre, and the
siliceous ingredient is in finer grains ; when burnt it adheres strongly to the
tongue, but its texture is not visibly porous. When containing little or no oxyd
of iron, it burns to a very good white color, and is very infusible ; pipes are made
of it, and it forms the basis of the white Staffordshire ware. If it contains oxyd
of iron sufficient to color it red, when baked, it becomes much more fusible, and
can only be employed in manufacturing the coarser kinds cf pottery.
Meagre clay is such, as, when dry, does not take a polish from rubbing it with
the nail ; it feels gritty between the teeth, and the sand which it contains is in
visible grains. When burnt without addition, it has a coarse granular texture,
and is employed in the manufacture of bricks and tiles.
Calcareous clay effervesces with acids, is unctuous to the touch, and always
contains iron enough to give it a red color when baked. It is much more fusible
than any of the preceding kinds, and is only employed in brick-making. By
judicious burning it may be made to assume a semi- vitreous texture, and bricks
thus made are very durable.
Clays are very abundant in nature, and contribute the most to the wants and
conveniences of man of all the earthy minerals.
SECTION II. — Brick-haking.
The clay for the purpose of making bricks should be dug in the autumn, and
piled in solid heaps. During the w'inter it should be broken up, and exposed in
such masses, from day to day, as to become thoroughly penetrated by the frost.
In the spring the clay is to be broken into small pieces, and shovelled over, in
order to expel the frost. After this is done, it is thrown into pits, and mixed with
fine sand and a suitable proportion of water ; the sand should be clear, free from
lumps of marl and saline particles, — siliceous sand is to be preferred, — and the
water must be fresh. The ingredients are to be worked over by the means ot
OF BRICK-MAKING. 45
the shovel, treacling, or the wheel, till they are properly incorporated, and are of a
suitable consistency. In this way they are prepared for the striker’s bench.
In preparing for a brick-yard, the surface of the ground should be cleared and
levelled ; a coat of sand, two or three inches in depth, is to be put upon it, and
rendered as hard and as smooth as is practicable, by passing a heavy roller sev-
eral times over it when wet. After this a thin layer of sand is sifted upon the
surface, and a wooden scraper passed over it, in order to render it as smooth and
even as possible. The yard should be of a size sufficient to contain the bricks
that may be struck in two days.
Brick-moulds are commonly made to contain six bricks each. The striker is
prepared with two moulds, and a trough of water. When the prepared clay is
shovelled on to the striker’s table, he takes his mould from the trough of water,
adjusts it on a thin, level board bottom, and with his hands wet, to prevent adhe-
sion, strikes from the pile of mortar or prepared clay a quantity a little more than
sufficient to fill one of the apertures of the mould, which he drops into it with
considerable force, and presses it firmly down ; he then strikes the surplus ofi’
with his hand, and thus proceeds (ill all the apertures of the mould are filled.
A second person (called the carrier) now takes the full mould from the striker’s
table to another part of the brick -yard, and puts it down bottom upwards. The
bottom board is then drawn ofT diagonally, in order to preserve the edges of the
bricks entire, the mould is raised, and the bricks left on the sand to dry. The
carrier returns the empty mould to the striker’s trough, takes the second full
mould, and deposits the bricks as before. The bricks are thus exposed in ranges
till they are so dry as not to be easily defaced ; they are then placed upon their
edges, and remain till they are dry enough to be put into hacks. The hacks are
composed of alternate layers of bricks ; the lirst layer is called stretcher, and the
second header ; interstices or spaces are left between the bricks of from three
eighths to half an inch, so that the air may have a free circulation between them.
The bricks ought to remain in this situation till they are dry enough to go into
the kiln, or at least for six or eight weeks of dry weather. The hacks may be
of the thickness of three or four bricks placed lengthwise, and six or eight feet hi
height. They are to be protected from storms by sheds erected for the pur-
pose.
In forming bricks into a kiln, they are laid in benches, with arches, or apertures
for the fuel. A bench is formed in this manner. Courses of brick, or the
stretchers, are laid lengthwise ; and across the stretchers, or at right angles with
them, are laid other courses, or headers ; interstices are left between the bricks
from one fourth to one half an inch in thickness. The stretchers and headers
alternate with each other, and four courses of them form a bench. Between
46
PRACTICAL MASONRY.
every two benches, there is a space left, two bricks’ length in breadth, for arches.
The arches are formed by the gradual projection of the courses in the two
benches, about as far as the eighth course, where the courses of the benches, on
each side of the space, meet, at the distance, generally, of thirty-two inches from
the ground. The benches are commonly raised to the height of seven or eight
feet. Thus the benches and arches alternate with each other, till the number is
increased, as it may be deemed expedient. The bricks in the bench are placed
on their edges, and care should be taken to preserve throughout the interstices
between their sides so that the heat may percolate. At the top of the kiln, the
outside walls should have an inclination inwards, of about one foot in seven of
perpendicular height. The kiln is faced by refuse or unburnt bricks, laid up in
clay mortar, extending round the whole exterior of the kiln, the thickness of the
width of a single brick. The mouths of the arches are to be left open, and flat
stones prepared for closing them w’hile the kiln is in the progress of burning.
The moulds used in the vicinity of Boston are commonly eight and three
eighths inches in length, two and one eighth in thickness, and four and one
half in width ; and bricks, when burnt, vary from eight to seven and three
fourths inches in length, and are about four inches in width, and two in thickness,
according to the length of time and the degree of heat to which they have been
exposed.
The burning is commenced with a moderate heat, in order first to expel the
moisture. When this is done, the smoke changes from a great degree of black-
ness to a thin, transparent glimmering.
Then the intensity of the heat is increased to as great a degree as the material
will bear, without being fused, which is continued till a contraction, or shrinkage,
takes place at the top of the kiln, and at the ends of the arches opposite to those
in which the fuel is placed. When this is the case, it is necessary to close the
mouths of the arches at which the fuel has been inserted, and to put it in at the
mouths opposite. At the close of the process of burning, the arches are filled
with hard wood and then closed, and the kiln is suflered to I’emain thus till the
bricks are sufficiently cool for handling, before they ai’e exposed to the air.
A machine has recently been patented and put in operation in this vicinity for
preparing the materials for brick, which seems to possess many advantages over
the common method. The machine consists of a wheel for mixing the mortar,
and apparatus for filling the moulds, and is worked by horse or steam power.
It possesses, among others, the following advantages : that of pulverizing the clay
more thoroughly, and producing a more homogeneous and compact paste, and in
consequence the bricks are less liable to crack in the operation of drying or burn-
ing, and, by being more firmly pressed into the moulds, the\’ are less liable to
OF FACED OR PRESSED BRICKS.
47
absorb moisture from the atmosphere, and are rendered smoother ; and as less
water is required by this mode in making the paste, the bricks do not require the
same length of time in drying, while they are subject to shrink less in burning
than in the common method ; and lastly, much time and labor are saved in the
operation.
SECTION III. — Faced or Pressed Bricks.
These bricks are used to form the facing of walls in the better kind of struc-
tures, and are finished in a machine. The roughness and change of form, to
which common bricks are liable, is owing in part to the evaporation of a portion
of the water which the clay contains. To remedy the difficulty arising from this
cause, the bricks, after being moulded in the common manner, are exposed to the
sun till they are nearly di'ied, retaining, however, sufiicient plasticity to be still
capable of a slight change of form. The moulds, however, are somewhat larger
than those of the common bricks, in oixler that the bricks, when pressed, may be
of a sufficient size. The press machine is usuall}' made of cast iron, and contains
a number of moulds arranged in a circle or otherwise, so that the power is applied
to them in succession, and the bricks pressed with rapidity. The mould is of
sufficient thickness to resist about a ton’s weight applied to the top of a follower.
The follower is fitted as near as practicable to the inner side of the mould, and
kept in a proper position to be forced through, when the moulds a'’e removed
from their beds. This is done by the means of a wheel or slide, to which the
mould is attached. The bricks, being pressed, are received on a carrying-board.
The force is applied for pressing the bricks by the means of a double pui'chase
lever, or by the revolution of a wheel wnth rollers running on an oblique plane.
In this manner about five thousand bricks may be pressed olT in a day, by the
labor of two men and a horse.
The pressed bricks are of a superior quality in point of durability and ele-
gance. They form a w^all with a surface of great smoothness, and when
carefully laid produce a pleasing effect. These bricks are durable from their
hardness and smoothness, being less liable to decomposition from the action of
the atmosphere.
A patent was obtained in England, about the year 1795, by Mr. Cartwright,
for an improved system of making bricks, of which the following extract wall fur-
nish all necessary information.
“Imagine a common brick, w'ith a groove on each side dowm the middle,
rather more than half the wddth of the side of the brick ; a shoulder will thus be
48
PRACTICAL MASONRY.
left on each side of the groove, each of which will be nearly equal to one quarter
of the width of the side of the brick, or to one half of the groove or rabbet. A
course of these bricks beifig laid shoulder to shoulder, they will form an indented
line of nearly equal divisions, the grooves being somewhat wider than the adjoin-
ing shoulders, to allow for the mortar or cement. When the second course is
laid on, the shoulders of the bricks which compose it will fall into the grooves of
the first course, and the shoulders of the first course will fit into the grooves of
the second, and so with every succeeding course. Buildings constructed of these
bricks will require no bond timbers, as an universal bond runs through the whole
building, and holds all the parts together; the walls of which will neither crack
nor bilge without breaking through themselves. When bricks of this construction
are used for arches, the sides of the grooves should form the radii of a circle, of
which the intended arch is a segment. In arch work the bricks may either be
laid in mortar or dry, and the interstices afterwards filled up by pouring in lime,
putty, plaster of Paris, &c. Arches of this kind, having any lateral pressure,
can neither expand -at the foot or spring at the crown ; consequently they need
no abutments; neither will they need any superincumbent w’eight on the crown
to prevent them from springing up. The centres may also be struck immediately,
so that the same centre, which never need be many feet wide, may be regularly
shifted as the work proceeds. But the most striking advantage attending this
invention is the security it affords against fire ; for, from the peculiar properties of
this kind of arch, requiring no abutments, it may be laid upon or let into common
walls, no stronger than what are required for timbers, so as to admit of brick
floorings.”
SECTION IV. — Brick Masonry.
The use of bricks in building may be traced to the earliest ages, and they are
found among the ruins of almost every ancient nation. The earliest edifices of
Asia were constructed of bricks, dried in the sun and cemented with bitumen.
Of this material was built the ancient city of Nineveh. The walls of Babylon,
some of the ancient structures of Egypt and Persia, the walls of Athens, the
rotunda of the Pantheon, the Temple of Peace, and the Thermae, at Rome, were
all of brick. The earliest bricks were never exposed to great heat, as appears
from the fact that they contain reeds and straw, upon which no mark of burning
is visible. These bricks owe their preservation to the extreme dryness of the
climate in which they remained, since the earth of which they were made often
OF BRICK MASONRY.
49
crumbles to pieces when immersed in water, after having kept its shape for more
than two thousand years. This is the case of some of the Babylonian bricks,
with inscriptions in the arrow-headed character, which have been brought to this
country. The ancients, however, at a later period, burnt their bricks, and it is
these chiefly which remain at the present day. The antique bricks were larger
than those employed by the moderns, and were almost universally of a square
form. Those of Rome appear to have been of three different sizes ; the largest
were about twenty-two inches square, and two and one fourth inches thick ; the
second size sixteen and one half inches square, and from one and one half to
two inches thick ; the smallest size about seven and one half inches square, and
one and one half inches thick. In order to secure more effectually the facing
with rubble, the Romans placed in their walls, at intervals of every three or four
feet, two or three courses of the larger brick. (See Plate 22, Fig. 12.) The
larger bricks w'ere used in the formation of arches, and in the openings of build-
ings.
The bricks of the Greeks were commonly cubical and of different sizes. One
size was a foot on all sides, another kind fifteen inches; the former w^as chiefiy
used in the construction of private, and the latter in public edifices. There w^as
a third kind, a foot square and six inches thick, and a fourth kind, fifteen inches
square and seven and a half inches thick ; these last two kinds were called half-
bricks, and were used for the purpose of better effecting the construction of a
bond. (See Plate 22, Fig. 3.) They also employed, as well as the Romans,
another size, for ornamental walls, called net- work. (See Plate 22, Fig. 13.)
This net-work had a beautiful appearance, but was liable to crack ; in conse-
quence, according to Palladio, there are no ancient specimens of this kind
remaining. Vitruvius, however, states the form of these bricks to have been a
parallelogram, six inches wide, and from twelve to twenty-four inches long.
The baked bricks of the ancients were generally made of two parts of earth
and one of cinders, well tempered together. They were taken from the moulds
and left to dry in the sun for several days, and afterwards placed in a large fur-
nace, ranged one over another, at some distance apart ; the spaces between were
filled with plaster, or a sort of strata of fine coal.
Besides bricks made of clay, the ancients also employed a kind of factitious
stone, composed of a calcareous mortar. They were also in the habit of using
bricks and stones, both rubble and wrought, in the same wall.
In a rubble wall, three courses of bricks were laid at intervals of two or three
feet, for the purpose of binding the mass together ; the angles were also support-
ed by piers of stone or bricks. (See Plate 22, Fig 11.)
In buildings of more magnificence, (see Plate 22, Fig. 12,) the rubble was con-
7
50
PRACTICAL MASONRY.
cealed in the wall. The bottom of the wall was formed of six courses of large
bricks, then courses of smaller bricks were laid up to the height of three feet.
Then the wall was bound again with three courses of large bricks, and so on.
Examples of this kind of wall still remain in the Pantheon, and Warm Baths
of Dioclesian.
SECTION V. — Tiles.
Tiles are plates of burnt clay resembling bricks in their composition and man-
ufacture, and used for the covering of roofs. They are necessarily made thicker
than slates, or shingles, and thus impose a greater weight upon the roofs. Their
tendency to absorb water promotes the decay of the wood-work beneath them.
Tiles are usually shaped in such a manner that the edge of one tile receives
the edge of that next to it, so that water cannot percolate between them. Tiles,
both of burnt clay and marble, were used by the ancients, and the former con-
tinue to be employed in various parts of Europe. Floors, made of flat tiles, are
used in many countries, particularly in France and Italy.
SECTION VI. — Compact Limestone.
The uses and geological characters of this substance render it peculiarly
interesting. The term compact, however, as applied to this stone, must be
received with some latitude ; for, although its texture is often very close and com-
pact, sometimes like that of wax, yet in other instances it is loose and earthy.
Among the numerous colors of compact limestone, the most frequent are the
various shades of gray, such as smoke-gray, yellowish-gray, bluish-gray, red-
dish and greenish-gray ; it is also seen grayish-white, grayish -black, flesh-red,
with some deep tints of red and yellow ; several of these colors often occur in the
same fragment, which are distinguished by the epithet of marbled.
It usually occurs in extensive, solid, compact masses, whose fracture is dull and
splintery, or even, and sometimes conchoidal. It is sometimes traversed by
minute veins of calcareous spar, which reflect a little light ; and some compact
limestones are also slaty. Its hardness is somewhat variable. Its specific gravity
usually lies between 2.40 and 2.75. It is opaque and more or less susceptible of
a polish.
Compact limestone is seldom, perhaps never, a pure carbonate ; but contains
from two to twelve per cent, of silex, alumine, and the oxyd of iron, on the last
OF THE BURNING OF LIME.
51
of which its diversified colors depend. In fact, by increasing the proportion of
argillaceous matter, it passes into marl. Some limestones, which effervesce con-
siderably with an acid, are still so impure, that they melt rather than bum into
lime.
The uses to which compact limestone is applied are various ; it is principally
employed as a building stone, and burnt for making lime and mortar ; nor is it less
important to the agriculturist as a manure, to the miner as a flux for the reduc-
tion of ores, to the soap-boiler, to the tanner, &c. It is a substance very abun-
dantly diffused throughout the globe.
It is from compact limestone, that lime, so extensively used in the arts, is
chiefly obtained ; pure white marble, or limestone, undoubtedly furnishes the
best lime, though but little superior to that obtained from gray, compact lime-
stone.
SECTION VII. — The Burning of Lime.
This is a process by which limestone, marble, shells, &c., are converted into
lime by means of heat, in kilns properly constructed for the purpose. By the
application of heat to any of these substances, their carbonic acid is driven off,
and leaves the lime in a powder.
The calcination of limestone may be effected by wood, coal, or peat, as fuel ; but
the heat should not much exceed a red heat, unless the stone employed he nearly
a pure carbonate. The fuel is placed in layers, alternately with those of the
stones, or calcareous materials in the kilns, and the process of burning continued
for any length of time, by repeated applications of fuel and the calcareous mate-
rials at the top ; the lime being drawn out occasionally from below, as it is burnt.
Fossil or mineral coal is supposed to be the most convenient and suitable
material for effecting this business, where it can be procured plentifully, and
at a sufficiently cheap rate; as it bums the stone or other calcareous matter
more perfectly, and of course leaves fewer cores in the calcined pieces than when
other sorts of fuel are employed for the purpose.
Peat, also, is highly recommended, for its cheapness and uniformity of heat.
When coal is used, the limestones are liable, from excessive heat, to run into solid
lumps, which may be avoided by the use of peat, as it keeps them in an open
state, and admits the air freely.
Count Rumford, with his usual attention to economy in fuel and in the ex-
pense of caloric, has invented an oven for preparing lime. It has the form of a
high cylinder, with a hearth at the side, and at some distance above the base.
52
PRACTICAL MASONRY.
The combustible is placed on the hearth, and burns with an inverted or reflected
flame. The lime is taken out at the bottom, while fresh additions of limestone
are made at the top ; and thus the oven is preserved constantly hot.
Limestone recently dug, and of course moist, calcines more easily than that
which has become dry by exposure to the air ; in the latter case it is found con-
venient even to moisten the stone, before putting it into the kiln.
Limestone loses about four ninths of its weight by burning, but is nearly of the
same bulk.
Lime thus obtained is called quicklime. If it be wet with water, it instantly
swells and cracks, becomes exceedingly hot, and at length falls into a white,
soft, impalpable powder. This process is denominated the slacking of lime. The
compound formed is called the hydrate of lime, and consists of about three parts
of lime to one of water. When intended for mortar, it should immediately be
incorporated with sand, and used without delay, before it imbibes carbonic acid
anew from the atmosphere. Lime doubles its bulk by slacking.
SECTION VIII. — Of Mortars and Cements.
In the construction of works in masonry, we generally employ some kind of
cementitious matter for connecting the stones together, and rendering them firm
and compact. When the works are to be exposed to the action of water imme-
diately after being built, this cementitious matter must be of such a nature that
it will harden under water. Hence it is, that we have occasion for two kinds of
mortar, one that will set and harden under water, called by Smeaton a water-
mortar, or cement ; and common mortar for ordinary buildings.
Common Mortar, it is almost superfluous to say, is a preparation of lime
and sand, mixed with water, which serves to unite the stones in the building of
walls, &c., and on the proper or improper manner in which such mortar is pre-
pared and used depends the durability and security of buildings ; we shall, there-
fore, here introduce many particulars on this head, discovered by Smeaton, Dr.
Higgins, &c., but which, not being generally known, have never been introduced
into general practice.
Limestone, marble, chalk, or shells, may be used to burn for lime for common
mortar, all these substances being composed chiefly of lime and carbonic acid ;
and if a piece of one of them be slowly burnt or calcined, so as to expel the
whole, or nearly the whole, of its carbonic acid, it loses about forty-four per cent,
of its weight ; and when a small quantity of water is added to the calcined mat-
ter, it swells, gives out heat, and falls into a finely divided powder called slacked
lime. The bulk of the powder is about double that of the limestone.
OF MORTAES AND CEMENTS.
53
If this powder be rapidly formed into a stiff paste with water, it sets or solidi-
fies as a hydrate of lime, and ultimately hardens by the absorption of carbonic
acid from the air. This constitutes common building mortar. Hydrate of lime
consists of one hundred parts of lime and thirty-one parts of water. Common
limestone consists of carbonate of lime, with very little of any other substances ;
it produces a white lime, which slacks freely when well burnt ; it dissolves in
diluted muriatic acid, with only a small portion of residue, and never contains
more than a trace of iron. It differs much in external characters, as chalk, mar-
ble, common compact limestone, &c.
These limestones do not form cements to set in water, without the addition of
other kinds of cementing matter ; hence they are usually employed only for com-
mon mortar. The hardest marble and the softest chalk make equally good lime
when well burnt; but chalk-lime will slack when not perfectly burnt, and, there-
fore, has a sufficient quantity of fire ; wdiereas stone-lime must have sufficient to
make it slack. It was also observed by Dr. Higgins, that stone-lime does not re-
absorb carbonic acid so rapidly as chalk-lime. Lime made from common lime-
stone sustains very little injury from being kept after it has been formed into
mortar, provided the air be effectually excluded ; indeed, Alberti mentions an
instance of some which had been covered up in a ditch for a very long time, and
yet was found to be of an excellent quality.
Sand. To employ lime alone in the composition of mortar would render it
expensive ; besides it would be of inferior quality. The 'material commonly used
to mix with lime is sand, and this sand should be of a hard nature, not very fine,
but angular, and having considerable affinity for lime ; also, the more irregular it
is in size the better. It should be free from any mixture of soft or earthy mat-
ter, if it can be procured without. The reason is obvious ; for mortar composed
of soft sand cannot be harder than that sand. Sea-sand makes good mortar,
particularly water-mortar. Very hard burnt brick, or tile, reduced to a coarse
powder, also makes an excellent substance to mix with lime, for many purposes.
The best proportion of sand for common mortar is easily ascertained by trial ;
enough should be added to render the mortar rather short than tough under the
trowel. The proportion varies from four parts of sand to one of lime, to one and
one fourth parts of sand to one of lime, by measure ; the proportion differing ac-
cording to the coarseness of the sand, the nature of the limestone, and the pre-
cautions used in burning it ; all set proportions being universally adhered to only
by those who are utterly ignorant of the subject. In many situations, it is impos-
sible to procure good sand except at an enormous expense.
Making Mortar. The instructions given by Dr. Higgins for making stucco
mortar apply only when a very superior kind is wanted ; but the same general
54
PRACTICAL MASONRY.
principles ought to be followed even with the commonest kinds of mortar. We
will therefore insert them in this place.
Of sand, the following kinds are to be preferred. First, drift-sand, or 'pit-sand,
which consist chiefly of hard, quartzose, flat-faced grains, with sharp angles. Sec-
ondly, that which is the freest, or may be most easily freed by washing, from
clay, salts, and calcareous, gypseous, or other grains less hard and durable than
quartz. Thirdly, that which contains the smallest quantity of pyrites, or heavy
metallic matter, inseparable by washing. And, fourthly, that which suffers the
smallest diminution of its bulk by washing. Where a coarse and fine sand of
this kind, and corresponding in the size of their grains with the coarse and fine
sands hereafter described, cannot be easily procured, let such sand of the fore-
going quality be chosen, as may be sorted and cleansed in the following manner.
Let the sand be sifted in streaming cold w'ater, through a sieve which shall
give passage to all such grains as do not exceed one sixteenth of an inch in di-
ameter ; and let the stream of water and the sifting be regulated so that all the
sand which is much finer than the Lynn sand, commonly used in the London
glasshouses, together with clay, and every other matter specifically lighter than
sand, may be washed away with the stream ; whilst the purer and coarser sand,
which passes through the sieve, subsides in a convenient receptacle, and the
coarse rubbish and rubble remain on the sieve, to be rejected.
Let the sand which thus subsides in the receptacle be washed in clean stream-
ing water, through a fine sieve, so as to be further cleansed, and sorted into two
parcels ; a coarser, which will remain in the sieve, which is to give passage to
such grains of sand only as are less than one thirtieth of an inch in diameter, and
which is to be saved apart, under the name of coarse sand; and a finer, which
will pass through the sieve and subside in the water, and which is to be saved
apart, under the name of fine sand. Let the coarse and the fine sand be dried
separately, either in the sun or on a clean plate, set on a convenient surface, in
the manner of a sand heat.
Let stone-lime be chosen which heats the most in slacking, and slacks the
quickest when duly watered ; that which is the freshest made and closest kept ;
that which dissolves in distilled vinegar with the least effervescence, and leaves
the smallest residue insoluble, and in the residue the smallest quantity of clay,
gypsum, or iron. Let the lime chosen according to these rules be put in a
brass-wdred sieve, to the quantity of fourteen pounds. Let the sieve be finer
than either of the foregoing ; the finer the better it will be. Let the lime be
slacked, by plunging it into a butt filled with soft water, and raising it out quickly,
and suffering it to heat and fume, and, by repeating this plunging and raising
alternately, and agitating the lime until it be made to pass through the sieve into
OF MORTARS AND CEMENTS.
55
the water ; and let the part of the lime which does not easily pass through the
sieve be rejected ; and let fresh portions of the lime be thus used, until as many
ounces of lime have passed through the sieve as there are quarts of water in the
butt.
Let the water, thus impregnated, stand in the butt closely covered, until it be-
comes clear, and through wooden cocks, placed at different heights in the butt,
let the clear liquor be drawn off, as fast and as low as the lime subsides, for use.
This clear liquor is called lime-water. The freer the water is from saline matter,
the better will be the cementing liquor made with it. Let fifty-six pounds of the
aforesaid chosen lime be slacked, by gradually sprinkling the lime-water on it, and
especially on the unslacked pieces, in a close clean place. Let the slacked part
be immediately sifted through the last mentioned brass-wired sieve ; and let the
lime which passes be used instantly, or kept in air-tight vessels, and the part of
the lime which does not pass through the sieve be rejected. This finer and rich-
er part of the lime, which passes through the sieve, may be called purified lime.
Let bone-ash be prepared in the usual manner, by grinding the whitest burnt
bones ; but let it be sifted, so as to be much finer than the bone-ash commonly
sold for making cupels.
The best materials for making cement being thus prepared, take fifty-six
pounds of the coarse sand, and forty- two pounds of white sand ; mix them on a
large plank of hard wood, placed horizontally ; then spread the sand so that it
may stand to the height of six inches, with a flat surface on the plank ; wet it
with the lime-water, and let any superfluous quantity of the liquor, which the sand
in the condition described cannot retain, flow away off the plank. To the wetted
sand add fourteen pounds of the purified lime, in several successive portions,
mixing and beating them up together, in the mean time, with the instruments
generally used in making fine mortar ; then add fourteen pounds of the bone-ash,
in successive portions, mixing and beating all together.
The quicker and the more perfectly these materials are mixed and beaten to-
gether, and the sooner the cement thus formed is used, the better it will be.
This may be called coarse-grained cement, which is to be applied in building,
pointing, plastering, stuccoing, or other work, as mortar and stucco generally are ;
with this difference chiefly, that, as this cement is shorter than mortar, or common
stucco, and dries sooner, it ought to be worked expeditiously, in all cases ; and
in stuccoing it ought to be laid on by sliding the trowel upwards on it. The
materials used along with this cement, in building, or the place on which it is to
be laid, in stuccoing, ought to be well wetted with the lime-water, in the instant
of laying on the cement. The lime-water is also to be used when it is necessary
to moisten the cement, or when a liquid is required to facilitate the floating of the
cement.
56
PRACTICAL MASONRY.
When such cement is required to be of a still finer texture, take ninety-eight
pounds of the fine sand, wet it with the lime-water, and mix it with the purified
lime and the bone-ash, in the quantities and in the manner described ; with this
difference only, that fifteen pounds of lime, or thereabouts, are to be used instead
of fourteen pounds, if the greater part of the sand be as fine as Lynn sand.
This may be called fine-grained cement. It is used in giving the last coating, or
the finish, to any work intended to imitate the finer-grained stones, or stucco.
But it may be applied to all uses of the coarse-grained cement, and in the same
manner.
When, for any of the foregoing purposes of pointing, building, &c., a cement
is required much cheaper and coarser-grained than either of the foregoing, then
much coarser clean sand than the foregoing coarse sand, or well washed fine
rubble, is to be provided. Of this coarse sand, or rubble, take fifty-six pounds ;
and after mixing these, and wetting them with the cementing liquor, in the fore-
going manner, add fourteen pounds, or somewhat less, of the purified lime, and
then fourteen pounds, or somewhat less, of the bone-ash, mixing together in the
manner already described. When the cement is required to be white, white sand,
white lime, and the whitest bone-ash are to be chosen. Gray sand, and gray
bone-ash, formed of half-burnt bones, are to be chosen to make cement gray ;
and any other color of the cement is obtained, either by choosing colored sand,
or by the admixture of the necessary quantity of colored talc, in powder, or of
colored, vitreous, or metallic powders, or other durable coloring ingredients com-
monly used in paint.
This cement, whether the coarse or fine-grained, is applicable in forming arti-
ficial stone, by making alternate layers of the cement and of flint, hard stone, or
bricks, in moulds of the intended stone, and by exposing the masses so formed
to the open air, to harden.
When such is required for water-fences, two thirds of the prescribed quantity
of bone-ashes are to be omitted ; and, in the place thereof, an equal measure of
powdered terras is to be used ; and if the sand employed be not of the coarsest
sort, more terras must be added, so that the terras shall be one sixth part of the
weight of the sand.
When such a cement is required of the finest grain, or in a fluid form, so that
it may be applied with a brush, flint-powder, or the powder of any quartzose or
hard earthy substance, may be used in the place of sand, but in a quantity smaller
in proportion as the flint or other powder is finer ; so that the flint-powder, or
other such powder, shall not be more than six times the weight of the lime, nor
less than four times its weight. The greater the quantity of lime within these
limits, the more will the cement be liable to crack by quick drymg, and vice versa.
OF MORTARS AND CEMENTS.
57
Where the above-described sand cannot be conveniently procured, or where
the sand cannot be conveniently washed and sorted, that which most resembles
the mixture of coarse and fine sand above prescribed may be used, as directed,
provided due attention be paid to the quantity of the lime, w^hich is to be greater
as the quality is finer, and vice versa.
Where sand cannot be easily procured, any durable stony body, or baked
earth, grossly powdered and sorted nearly to the sizes above prescribed for
sand, may be used in the place of sand, measure for measure, but not weight for
weight, unless such gross powder be specifically as heavy as sand.
Sand may be cleansed from every softer, lighter, and less durable matter, and
from that part of the sand which is too fine, by various methods, preferable, in
certain circumstances, to that which has been already described.
Water may be found naturally free from fixable gas, selenite, or clay ; such
^vater may, without any great inconvenience, be used in the place of the lime-
w'ater ; and water approaching this state will not require so much lime as above
prescribed to make the lime-water ; and a lime-w’ater sufficiently useful may be
made by various methods of mixing lime and water, in the described proportions,
or nearly so.
When stone-lime cannot be procured, chalk-lime, or shell-lime, which best re-
sembles stone-lime in the foregoing characters of lime, may be used in the man-
ner described, excepting that fourteen pounds and a half of chalk -lime will be
required in the place of fourteen pounds of stone-lime. The proportion of lime,
as prescribed above, may be increased without inconvenience, when the cement
or stucco is to be applied where it is not liable to dry quickly ; and, in the con-
trary case, this proportion may be diminished. The defect of lime, in quantity or
quality, may be very advantageously supplied by causing a considerable quantity
of lime-water to soak into the work, in successive portions, and at distant intervals
of time ; so that the calcareous matter of the lime-water, and the matter attracted
from the open air, may fill and strengthen the work.
The powder of almost every well dried or burnt animal substance may be used
instead of bone-ash ; and several earthy powders, especially the micaceous and
the metallic ; and the elixated ashes of divers vegetables, whose earth will not
burn to lime, as well as the ashes of mineral fuel, which are of the calcareous
kind, but will not burn to lime, will answer the ends of bone-ash, in some degree.
The quantity of bone-ash described may be lessened without injuring the ce-
ment ; in those circumstances, especially, which admit the quantity of lime to be
lessened, and in those wherein the cement is not liable to dry quickly. The art
of remedying the defects of lime may be advantageously practised to supply the
deficiency of bone-ash, especially in building and making artificial stone with this
cement.
8
58
PRACTICAL MASONRY.
As the preceding method of making mortar differs, in many particulars, from
the common process, it may be useful to inquire into the causes on which this
difference is founded.
When the sand contains much clay, the workmen find that the best mortar
they can make must contain about one half lime ; and hence they lay it down as
certain, that the best mortar is made by the composition of half sand and half
lime.
But with sand requiring so great a proportion of lime as this, it will be impos-
sible to make good cement ; for it is universally allowed that the hardness of
mortar depends on the crystallization of the lime round the other materials which
are mixed with it, and thus uniting the whole mass into one solid substance.
But if a portion of the materials used be clay, or any other friable substance, it
must be evident, that, as these friable substances are not changed in one single
particular by the process of being mixed up with lime and water, the mortar of
which they form a proportion will consequently be more or less of a friable nature,
in proportion to the quantity of friable substances used in the composition of the
mortar. On the other hand, if mortar be composed of lime and good sand only,
as the sand is a stony substance, and not in the least friable, and as the lime, by
perfect crystallization, becomes likewise of a stony nature, it must follow, that a
mass of mortar, composed of these two stony substances, will itself be a hard,
solid, unfriable substance. This may account for one of the essential variations
in the preceding method from that in common use, and point out the necessity
of never using in the place of sand, which is a durable, stony body, the scrap-
ings of roads, old mortar, and other rubbish from ancient buildings, which are
frequently made use of, as all of them consist, more or less, of muddy, soft, and
minutely divided particles. Another essential point is the nature and quality of
lime. Now experience proves, that, when lime has been long kept in heaps or
untight casks, it is reduced to the state of chalk, and becomes every day less
capable of being made into good mortar ; because, as the goodness or durability
of the mortar depends on the crystallization of the lime, and as experiments have
proved that lime, when reduced to this chalk -like state, is always incapable of
perfect crystallization, it must follow that, as lime in this state never becomes
crystallized, the mortar, of which it forms the most indispensable part, will neces-
sarily be very imperfect ; that is to say, it will never become a solid stony sub-
stance ; a circumstance absolutely required in the formation of good durable
mortar. These are the two principal ingredients in the formation of mortar ; but,
as water is also necessary, it may be useful to point out which is the fittest for
this purpose ; the best is rain-water, river-water the second, land-water next,
and spring-water last. The ruins of the ancient Roman buildings are found to
OF MORTAES AND CEMENTS.
59
cohere so strongly, as to have caused an opinion that their constructors were
acquainted with some kind of mortar which, in comparison with ours, might just
ly be called cement; and that to our ignorance of the materials they used is
owing the great inferiority of modern buildings in their durability. But a proper
attention to the above particulars would soon show, that the durability of the
ancient edifices depended on the manner of preparing their mortar more than on
the nature of the materials used. The following observation will, we think,
prove this beyond a possibility of doubt. Lime which has been slacked and
mixed with sand becomes hard and consistent when dry, by a process similar to
that which produces stalactites in caverns. These are always formed by water
dropping from the roof. But when the small drop of water comes to be exposed
to the air, the calcareous matter contained in it begins to separate from the water,
and to reassume its native form of limestone or marble.
When the calcareous matter is perfectly crystallized in this manner, it is, to all
intents and purposes, limestone or marble of the same consistence as before. If
lime in a caustic state be mixed with water, part of the lime will be dissolved,
and will also begin to crystallize. The water which parted with the crystallized
lime will then begin to act upon the remainder, which it could not dissolve
before, and thus the process will continue, either till the lime be all reduced to
an effete or crystalline state, or something hinders the action pf water upon it. It
is this crystallization which is observed by the workmen when a heap of lime is
mixed with water, and left for some time to macerate. A hard crust is formed
upon the surface, which is ignorantly called frostling, though it takes place in
summer as well as in winter.
If, therefore, the hardness of the lime, or its becoming a cement, depends en-
tirely on the formation of its crystals, it is evident that the perfection of the cement
must depend on the perfection of the crystals, and the hardness of the matters
which are entangled among them. The additional substances used in making of
mortar, such as sand, brick-dust, or the like, serve only for a purpose similar to
what is answered by sticks put into a vessel full of any saline solution : namely,
to afford the crystals an opportunity of fastening themselves upon it. If, therefore,
the matter interposed between the crystals of the lime is of a friable, brittle na-
ture, such as brick-dust or chalk, the mortar will be of a weak and imperfect kind;
but when the particles are hard, angular, and very difficult to be broken, such as
those of river or pit-sand, the mortar turns out exceedingly good and strong.
That the crystallization may be the more perfect, a large quantity of water
should be used, the ingredients be perfectly mixed together, and the drying be
as slow as possible. An attention to these particulars, and to the quality of bricks
and stones, would make the buildings of the moderns equally durable with those
60
PRACTICAL MASONRY.
of the ancients. In the old Roman works, the great thickness of the walls neces-
sarily required a vast time to dry. The middle of them was composed of peb-
bles, thrown in at random, and which evidently had thin mortar poured in among
them. Thus a great quantity of the lime would be dissolved, and the crystalli-
zation performed in the most perfect manner. The indefatigable pains and per-
severance, for which the Romans were so remarkable in all their undertakings,
leave no room to doubt that they w’ould take care to have the ingredients mixed
together as well as possible. The consequence of all this is, that the buildings
formed in this manner are all as firm as if cut out of a solid rock, the mortar
being equally hard, if not more so than the stones themselves.
Water Mortars or Cements. The cementing materials are either found
ready combined in certain kinds of stone, as in the case of Roman cement ; or
the effect is produced by mixture, as when we mix the lime of poor limestones
with Dutch terras. The natural combination is, however, by far the best, and
it is only in cases where the other can be obtained at a much less expense, that
we advise it to be resorted to ; but for such cases we propose to describe the
best compositions now known.
Roman Cement is made from the kind of stones called clay-balls. The best
stone contains about sixty per cent, of carbonate of lime, and eight or ten per cent,
of protoxyd of iron, the rest being silex and alumine, nearly in equal parts. The
inferior stones contain peroxyd of iron, and often soluble earthy and alkaline salts.
Stone of the best kind is produced on the coast of the Isle of Sheppy, and from
the alum-shale on the coast of Yorkshire, near Whitby. Stone of an inferior
quality is procured near Harwich, and other places on the coast of England, and
at Boulogne, in France. The stone is, after being broken to a proper size, slow-
ly calcined in kilns or ovens, and then it is ground to a fine powder, of a light
snuff color, when the stone is good, and of a deeper, approaching to a burnt um-
ber-brown, when the quality is inferior. The powder should be kept perfectly
dry, till it is used ; and, in order to use it, mix it with not less than an equal por-
tion, by measure, of dry, clean, and sharp river-sand ; then add as much clear
water as will form it into a stiff paste, but not more ; and the whole that is so
mixed must be used before it begins to set, which, with good cement, happens
in about fifteen minutes from the time of adding water ; but, in cements very fit
for building, the setting may not be commenced in less than half or three quarters
of an hour. When the setting begins, all the moisture on the surface disappears,
and the cen>ent feels dry and warm to the touch, and hardens ; the hardening
continues for some months, and is increased by frequently wetting the work, in
cases where it has not to be exposed to water immediately on its being set. A
coat of this cement is impervious to water, and it is therefore used for lining cis-
OF MORTARS AND CEMENTS.
61
terns, tanks, reservoirs, &c. Roman cement may be used alone, but it does not
become so hard and durable as when it has a proper quantity of good sand
mixed with it. A mixture of Roman cement and common mortar should never
be made, for their setting properties depend on different combinations, which
interfere with each other when acting in the same mass ; and the best mortar and
best cement may be both rendered worthless by mixture. In using cement
the more expeditious the workman is in his operations the better ; and when
once setting has commenced, the work should be no further disturbed. If the
setting take place too rapidly for the nature of the work, let the cement, in pow-
der, be spread out so as to expose a large surface to the air, in a dry place ; in
this manner the time of setting may be extended according to the time the pow-
der is exposed ; and though the quality of the cement is injured by the process,
it is not so much destroyed as by working the cement after its being partially set.
Puzzolana Mortar. An excellent mortar for water- works is formed b}^ com-
bining the lime of poor limestones with the earth called puzzolana, which is
procured in Italy. The limestones adapted for this purpose are the blue lias of
Somersetshire, the clunch of Sussex, and the hard, gray chalk of Surrey. Smea-
ton used the lime of the lias, procured at Aberthaw, in Wales, for the Eddystone
lighthouse, the proportions as
follows : —
Kind o f Mortar,
Lime in Powder.
Puzzolana.
Cleati Sand.
No. 1. Eddystone Mortar,
2 bushels.
2 bushels.
No. 2. Stone Mortar,
2 “
1
1 bushel.
No. 3. Do. (2d sort).
2 “
1 “
2 “
No. 4. Face Mortar,
2 “
1
3 “
No. 5. Do. (2d sort).
2 “
4 “
3 “
No. 6. Backing Mortar,
2 “
i “
3 “
Smeaton remarks, that mortar of the proportions of No. 1 will, in twelve months,
acquire the hardness of Portland stone, when under water ; and the others will
in time acquire a stony hardness, if the materials have been thoroughly mixed and
well beaten together. An article called British puzzolana has lately been manu-
factured, but it does not possess the same properties as the foreign kind, and, in-
deed, is rather a substitute for sand than for the true puzzolana.
Terras Mortar is also very good for water-works ; it is composed of an
earthy material called terras, found near Andernach, in the department of the
Rhine and Moselle, which is mixed with any lime of a nature similar to the blue
lias. Terras is much used by the Dutch, for their sea and canal works, and it
has the singular property of forming stalactitical excrescences at the joints of the
work. Smeaton employed it in the following proportions, according to the nature
of the work. No. 1 being the best quality.
62
PRACTICAL MASONRY.
No. 1. Terras Mortar,
Kind of Mortar.
Lime in Powder.
2 bushels,
Terras.
1 bushel.
Clean Sand.
No. 2. Do. (2d kind).
No. 3. Do. (3d kind).
No. 4. Do. (4lh kind).
No. 5. Backing Mortar,
2 “
2 “
2 “
2 “
1 “
2
1 “
1 “
1 “
2 “
3 “
3 “
1 bushel.
The customary allowance of beating for terras mortar is a day’s work of a man
for every bushel of terras. When neither Roman cement, puzzolana, nor terras
can be procured, except at great expense, then we may have recourse to cal-
cined iron ore, scales from smiths’ forges, calcined basalt, clay, and other sub-
stances containing a considerable proportion of protoxyd of iron. Lime may
also be improved by peculiar treatment in burning, for it appears that even com-
mon chalk-lime acquires a setting property resembling that of the lias-lime, by
being long exposed to a certain degree of heat. All limes fit for water-cements
require to be ground to powder, and the finer the better. If these limes be
slacked, the setting property is partially destroyed ; and it is important that no
more mortar should be made up at once than can be used within a few hours.
These are the substances generally made use of for the uniting medium be-
tween bricks or stones, in forming them into buildings. Though many experi-
ments have been made to ascertain the best materials for these compounds, and
the mode of mixing them, and not without a degree of success, still much yet
seems to remain to be discovered. A composition of lime, sand, and water, in
consequence of the facility with which they pass from a soft state to a stony hard-
ness, has, in common uses, superseded all other ingredients. But in order that
the mortar should be of a good quality, great care and skill are requisite in the
selection of the materials and the proportioning of them ; and much depends on
the degree of labor bestowed on the mixing and incorporation. The lime should
be well burnt, and free from fixed air and carbonic acid. Hence, lime that has
become effete, from exposure to the atmosphere, is impaired in its quality. The
sand most proper for mortar is that which is wholly siliceous, and which is sharp,
that is, not having its particles rounded by attrition. Fresh sand is to be pre-
ferred to that taken from the vicinity of the sea-shore, the salt of which is liable
to deliquesce and weaken the strength of the mortar ; it should be clean, rather
coarse, and free from dirt and all perishable ingredients. The water should be
pure, fresh, and, if possible, free from fixed air.
SECTION IX. — Co.MMON Mortar and Cement.
OF COMMON MORTAR AND CEMENT.
63
The proportions of lime and sand to each other are varied in different places ;
the amount of sand, however, always exceeds that of lime. The more sand that
can be incorporated with the lime, the better, provided the necessary degree of
plasticity is preserved ; for the mortar becomes stronger, and it also sets, or con-
solidates more quickly, when the lime and water are less in quantity and more
subdivided. From two to four parts of sand are commonly used to one of lime,
according to the quality of the lime and the labor bestowed upon it. The more
pure the lime is, and the more thoroughly it is beaten or worked over, the more
sand it will take up, and the more firm and durable does it become.
SECTION X.
The ancient masons were so very scrupulous in the process of mixing their
mortar, that it is said the Greeks kept ten men constantly employed, for a long
space of time, to each basin ; this rendered their mortar of such prodigious hard-
ness, that, Vetruvius tells us, the pieces of plaster falling off from old walls served
to make tables.
It was a maxim among the old masons to their laborers, that they should dilute
the mortar with the sweat of their brows ; that is, labor a long time, instead of
drowning it with w'ater, to have it done the sooner.
The weakness of modern mortar compared to the ancient is a common sub-
ject of regret ; and many ingenious men take it for granted, that the process
used by the Roman architects in preparing their mortar is one of those arts which
are now lost, and have employed themselves in making experiments for its
recovery.
But the characteristic of all modern artists, builders among the rest, seems to
be, to spare their time and labor as much as possible, and to increase the quanti-
ty of the article they produce, without much regard to goodness ; and perhaps
there is no manufacture in which it is so remarkably exemplified as in the prepa-
ration of common mortar.
SECTION XL
Mr. Doffie gives the following method of making mortar impenetrable to moist-
ure, acquiring great hardness, and exceedingly durable, which was discovered by
a gentleman of Neufchatel. Take of unslacked lime and of fine sand, in the pro-
portion of one part of lime to three of sand, as much as a laborer can well manage
64
PRACTICAL MASONRY.
at once ; and then, adding water gradually, mix the whole well together with a
trowel, till it be rendered to the consistency of mortar. Apply it immediately,
while it is hot, to the purpose either of mortar as a cement to brick or stone, or
of plaster to the surface of any building. It will then ferment for some days, in
drier places, and afterwards gradually concrete or set, and become hard ; but in
a moist place it will continue soft for three weeks or more ; though it will at
length obtain a firm consistence, even if water have such access to it as to keep
the surface wet the whole time. After this it will acquire a stone-like hardness,
and resist all moisture. The perfection of this mortar depends on the ingredients
being thoroughly blended together ; and the mixture being applied immediately
after to the place where it is wanted. The lime for this mortar must be made of
hard limestone, shells, or marl ; and the stronger it is, the better the mortar will
be. When a very great hardness and firmness are requisite in this mortar, the
using of skimmed milk instead of water, either wholly or in part, will produce the
desired effect.
SECTION XII. — Monsieur Loriat’s Mortar.
Monsieur LoriaVs Mortar, the method of making which was announced by
order of his Majesty, at Paris, in 1774, is made in the following manner: —
Take one part of brick dust, finely sifted, two parts of fine river-sand, screened,
and as much old slacked lime as may be sufficient to form mortar with water, in
the usual method, but so wet as to serve for the slacking of as much powdered
quicklime as amounts to one fourth of the whole quantity of brick-dust and sand.
When the materials are well mixed, employ the composition quickly, as the least
delay may render the application imperfect, or impossible. Another method of
making this compound is, to make a mixture of the dry materials that is, of the
sand, brick-dust, and powdered quicklime, in the prescribed proportion ; which
mixture may be put into sacks, each containing a quantity sufficient for one or
two troughs of mortar. The above-mentioned old slacked lime and water being
prepared apart, the mixture is to be made in the manner of plaster, at the instant
when it is wanted, and is to be well chafed with the trowel.
METHOD OF MAKING MORTAR.
65
SECTION XIII.
Dr. Higgijvs has made a variety of experiments, in consequence of the mod-
ern discoveries relating to fixed air, for the purpose of improving mortar used in
buildings. According to this author, the perfection of lime, prepared for the pur-
pose of making mortar, consists chiefly in its being totally deprived of its fixed
air. And as lime very quickly imbibes fixed air, when exposed to the atmos-
phere, it should be applied to use as soon as possible after it is prepared.
From the experiments of the same author, made with a view to ascertain the
best relative proportions of lime, sand, and water, in the making of mortar, it
appeared that those specimens were the best which contained one part of lime in
seven of sand; for those which contained less lime, and were too short while fresh,
were more easily cut and broken, and were pervious to water ; and those which
contained more lime, although they were closer in grain, did not harden so soon,
or to so great a degree, even when they escaped cracking by lying in the shade
to dry slowly.
Dr. Higgins has also shown, that though the setting of mortar, as it is called, is
chiefly owing to its drying, yet its induration, or its acquiring a stony hardness,
is not caused by its drying, as has been supposed, but depends principally on its
acquiring carbonic acid, or fixed air from the atmosphere. In order to the great-
est induration of mortar, therefore, it must be suffered to dry gently, and set ; the
drying must be effected by temperate air, and not accelerated by the heat of the
sun, or fire. It must not be wet soon after it sets ; and afterwards, it ought to
be protected from wet as much as possible, until it is completely indurated. The
same author describes a cement, or stucco, of his own invention, for incrustations
external and internal, of very great hardness, for which he obtained letters patent.
As for the materials of which it is made, drift sand, or quarry sand, consisting
chiefly of hard, quartzose, flat-faced grains, with sharp angles, free from clay, salts,
&.C., is to be preferred. The sand is to be sifted in streaming clear water,
through a sieve which shall give passage to all such grains as do not exceed one
sixteenth of an inch in diameter ; and the stream of water, and sifting, are to be
so regulated, that all the finer sand, together with clay and other matter lighter
than sand, may be washed away with the stream. While the purer and coarser
sand, which passes through the sieve, subsides in a convenient receptacle, the
coarse rubbish in the sieve is to be rejected. The subsiding sand is then washed
in clean streaming water, through a finer sieve, so as to farther cleanse it, and
sorted into two parcels, — a coarser, which will remain in the sieve, which is to
9
66
PRACTICAL MASONRY.
give passage only to such grains as are less than one thirteenth of an inch in
diameter, and which is to be kept apart under the name of coarse sand ; and a
finer which will pass through the sieve, and subside in the w^ater, and which is to
be saved apart under the name of fine sand. These are to be dried separately,
either in the sun or on a clean iron plate, set on a convenient surface, in the man-
ner of a sand heat. The lime to be chosen should be stone-lime, w'hich heats
the most in slacking, and slacks the quickest w'hen duly watered ; which is the
freshest made, and most closely kept. Let this lime be put into a brass-wired,
fine sieve, to the quantity of fourteen pounds. Let the lime be slacked by plunging
it in a butt, filled with soft w'ater, and raising it out quickly, and suffering it to
heat and fume, and by repeating this plunging and raising alternately, and agitat-
ing the lime, until it be made to pass through the sieve. Reject the part of the
lime that does not easily pass through the sieve, and use fresh portions of lime
till as many ounces have passed through the sieve as there are quarts of water in
the butt. Let the w'ater thus impregnated stand in the butt, close covered, until
it becomes clear ; and through wooden cocks, placed at different heights in the
butt, draw oft' the clear liquor, as fast and as low as the lime subsides, for use.
This clear liquor is called the cementing liquor.
Let fifty-six pounds of the aforesaid chosen lime be slacked, by gradually
sprinkling on it the cementing liquor, in a close, clean place. Let the slacked
part be immediately sifted through the fine brass-wired sieve. Let the lime
which passes be used instantly, or kept in air-tight vessels, and let the part of the
lime which does not pass through the sieve be rejected ; the other part is called
purified lime.
Let bone-ashes be prepared in the usual manner, by grinding the whitest burnt
bones ; but they should be finely sifted.
Having thus prepared the materials, take fifty-six pounds of the coarse sand,
and forty-two pounds of the fine sand ; mix them on a large plank of hard wood,
placed horizontally. Then spread the sand so that it may stand at the height of
six inches, with a flat surface on the plank ; wet it with the cementing liquor ; to
the wetted sand add fourteen pounds of the purified lime, in several successive
portions, mixing and beating them together ; then add fourteen pounds of the
bone-ashes in successive portions, mixing and beating them all together. This
Dr. Higgins calls the water cement, coarse-grained, which is to be applied in
building, pointing, plastering, stuccoing, &.c. Observing to work it expeditiously
in all cases, and in stuccoing to lay it on by sliding the trowel upwards upon it ;
to w'ell wet the materials used with it, or the ground on which it is laid, with the
cementing liquor, at the time of laying it on ; and to use the cementing liquor
for moistening the cement and facilitating the floating of it.
METHOD OF MAKING MORTAR.
67
A cement of a finer texture may be made, b}’ using ninety pounds of the fine
sand, and fifteen pounds of lime, with bone-ashes and cementing liquor. This is
called water cement, fine-grained, and is used in giving the last coating or finish
to anv work intended to imitate the finer-grained stones or stucco.
For a cheaper or coarser cement, take of coarse sand fifty-six pounds, of the
foregoing coarse sand twenty-eight pounds, and of the finer sand fourteen pounds ;
and after mixing and wetting these with the cementing liquor, add fourteen
pounds of the purified lime, and then as much bone-ashes, mixing them together.
The water cement above described is applicable to forming artificial stone, by
making alternate layers of the cement and of Hint, hard stone, or brick, in moulds
of the figure of the intended stone, and by exposing the masses so formed to the
open air to harden. When the cement is required for water fences, two thirds
of the bone-ashes are to be omitted, and in their stead an equal measure of pow-
dered terras (see Terras) is to be used. When the cement is required of the
finest grain, or in a fluid form, so that it may be applied with a brush. Hint pow-
der, or the powder of any quartzose, or hard, earthy substance, may be used in the
place of sand, so that the powder shall not be more than six times the weight of
the lime, nor less than four times its weight. For inside work the admixture of
hair with the cement is useful.
When a fragment of a worked stone is, by accident or otherwise, broken ofl',
it may be united with a firmness suflicient to resist a considerable degree of
force by a cement made of five parts gum shellac, and one part of Burgundy \‘
pitch, incorporated together in an iron vessel, over a slow fire. The cement,
while hot, should be applied to the stone, raised also to a moderate degree of
heat. In order that the cement should not cool too rapidly, a piece of iron should
be heated, and laid on the stone, and the whole suHered to cool gradually togeth-
er. The cement may be made to assume the color of the stone to be united, by
mixing with it a portion of the stone itself, reduced to a fine powder. Stones
thus united may afterwards be smoothed by gentle hammering, while the fracture
is not perceptible, except by very close examination.
SECTION XIV.
Although a well made moi-tar, composed merely of sand and lime, allowed
to dry, becomes impervious to water, so as to serve for the lining of reservoirs
and aqueducts; yet if the circumstances of the building are such as to render it
impracticable to keep out the water, whether fresh or salt, a suflicient length of
time, the use of common mortar must be abandoned.
68
PRACTICAL MASONRY.
Among the nations of antiquity, the Romans appear to have been the only peo-
ple who have practised building in water, and especially in the sea, to any ex-
tent. The bays of Baiae, of Pozzuolo, and of Cumae, from their coolness and sa-
lubrity of situation, were the fashionable resorts of the wealthier Romans, during
the summer months ; who not only erected their villas and baths as near the shore
as possible, but constructed moles and formed small islands in the more sheltered
parts of these bays ; on which, for the sake of the grateful coolness, they built
their summer-houses and pavilions. They were enabled to build thus securely
by the discovery, at the town of Puteoli, of an earthy substance, which was called
pulvis puteolanus, Puteolan powder, or, as it is now called, puzzolana (which see).
The only preparation which this substance undergoes is that of pounding and
sifting, by which it is reduced to a coarse powder ; in this state, being thoroughly
beaten up with lime, either with or without sand, it forms a mass of remarkable
tenacity, which speedily sets, under water, and becomes, at least, as hard as good
freestone.
Limes which contain a portion of clay, or argillaceous matter, have also the
property of forming a mortar, which hardens under water. A composition formed
of two bushels of clayey lime, one bushel of puzzolana, and three of clean sand,
the whole being well beaten together, make a good water cement.
The terras which is so much used in Holland is a preparation of a species of
basalt (which see), by calcination. It possesses the property, when mixed with
lime, of forming a water cement, not inferior to puzzolana. Perhaps common
greenstone and other substances may be found to answer the same purposes.
The materials of terras mortar, generally used in the construction of the best
water work, are one measure of quicklime, or two measures of slacked lime, in
the dry powder, mixed with one measure of terras, well beaten together to the
consistency of paste, using as little water as possible.
Another kind almost equally good, and considerably cheaper, is made of two
measures of slacked lime, one of terras, and three of coarse sand ; it requires to
be beaten longer than the foregoing, and produces three measures and a half of
excellent mortar. When the building is constructed of rough, irregular stones,
where cavities and large joints are to be filled up with cement, the pebble or
coarse-sand mortar may be most advantageously applied ; this was a favorite
mode of constructing among the Romans, and has been much used since. Peb-
ble mortar will be found of a sufficient compactness, if composed of two meas-
ures of slacked, argillaceous lime, half a measure of terras, or puzzolana, and one
measure of coarse sand, one of fine sand, and four of small pebbles, screened and
washed. It is only under water that terras mortar sets well.
The scales produced by hammering red-hot iron, which may be procured at
OF STUCCO.
69
the forges and blacksmiths’ shops, have been long knowm as an excellent materi-
al in water cements. The scales being pulverized and sifted, and incorporated
with lime, are found to produce a cement equally powerful with puzzolana mor-
tar, if employed in the same quantity.
Fresh-made mortar, if kept under ground, in considerable masses, may be
preserved for a great length of time, and the older it is before it is used, the bet-
ter it has been thought to be.
Pliny informs us that the ancient Roman laws prohibited builders from using
mortar that was less than three years old, and a similar law prevails in Vienna.
SECTION XV. — Stucco.
This is a composition of white marble, pulverized and mixed with plaster, or
lime, the whole sifted and wrought up with water, to be used like common plas-
ter.
Of this are made statues, busts, basso-relievos, and other ornaments of archi-
tecture.
A stucco, for walls, &,c., may be formed of the grout, or putty, made of good
stone-lime, or the lime of cockle-shells, which is better, properly tempered and
sufficiently beat, mixed with sharp grit sand, in a proportion which depends on
the strength of the lime. Drift-sand is best for this purpose, and it will derive
advantage from being dried on an iron plate or kiln, so as not to burn ; thus the
mortar would be discolored. When this is properly compounded, it should be
put in small parcels against walls, or otherwise, to mellow, as the workmen term
it ; reduced again to soft putty, or paste, and spread thin on the walls without
any under coat, and well trowelled. A succeeding coat should be laid on before
the first is quite dry, which will prevent points of brick-work appearing through
it. Much depends on the workman giving sufficient labor, and trowelling it
down. If this stucco, when dry, be laid over with boiling linseed oil, it will last a
long time, and not be liable, when once hardened, to the accidents to which com-
mon stucco is liable.
SECTION XVI.
Adam's Oil Cement, or Stucco, is prepared in the following manner. For the
first coat take twenty-one pounds of fine whiting, or oyster-shells, or any other
70
PRACTICAL MASONRY.
sea-shells calcined, or plaster of Paris, or any calcareous material calcined and
pounded, or any absorbent materials whatever, proper for the purpose ; add
white or red lead at pleasure, deducting from the other absorbent materials in
proportion for the white or red lead added ; to which put four quarts, beer meas-
ure, of oil, and mix them together with a grinding mill or any levigating machine;
and afterwards mix and beat up the same well with twenty-eight quarts, beer
measure, of any sand or gravel, or of both, mixed and sifted, or of marble or stone
pounded, or of brick-dust, or of any kind of metallic or mineral powders, or of
any solid material whatever, fit for the purpose.
For the second coat take sixteen pounds and a half of superfine whiting, or
oyster-shells, or any sea-shells calcined, &c., as for the first coat ; add sixteen
pounds and a half of white or red lead, to which put six quarts and a half of oil,
wine measure, and mix them together as before. Afterwards mix and beat up
the same well with thirty quarts, wine measure, of fine sand or gravel sifted, or
stone or marble pounded, or pyrites, or any kind of metallic or mineral powder,
&LC. This composition requires a greater proportion of sand, gravel, or other sol-
ids, according to the nature of the work, or the uses to which it is to be applied.
If it be required to have the composition colored, add to the above ingredients
such a portion of painters’ colors as will be necessary to give the tint or color
required. In making the composition, the best linseed, or hemp-seed, or other
oils, proper for the purpose, are to be used, boiled or raw, with drying ingre-
dients, as the nature of the work, the season, or the climate requires ; and in
some cases beeswax may be substituted in place of oil. All the absorbent and
solid materials must be kiln-dried. If the composition is not to be any other
color than white, the lead may be omitted, by taking the full proportion of the
other absorbents ; and also white or red lead may be substituted alone, instead of
any absorbent material.
The first coat of this composition is to be laid on with a trowel, and floated to
an even surface, with a rule or handle float. The second coat, after it is laid
on with a trowel, when the other is nearly dry, should be worked down and
smoothed, with floats edged with horn, or any hard, smooth substance, that does
not stain. It may be proper, previously to laying on the composition, to mois-
ten the surface on which it is to be laid, by a brush, with the same kind of oil
or ingredients which pass through the levigating machine, reduced to a more
liquid state, in order to make the composition adhere the better. This compo-
sition admits of being modelled, or cast in moulds, in the same manner as plas-
terers or statuaries model or cast their stucco-work. It also admits of being
painted upon, and adorned with landscape, or ornamental, or figure painting, as
well as plain painting.
OF SCAGLIOLA.
71
SECTION XVII. — ScAGLIOLA.
This composition has, of late years, begun to be much employed in the inte-
riors of mansions, and may be applied not only to columns, their capitals and
bases, but also to the panelling of walls, &c.
The formation of columns, &c., in scagliola, is a distinct branch of plastering.
It was first invented in Italy, thence carried to France, and afterwards to Eng-
land. The credit of its introduction into England belongs to Henry Holland,
Esq., architect.
He procured artists from Paris to perform w'orks with this composition at Carl-
ton Palace, some of whom, finding a considerable demand for their productions,
remained in England, from whom British workmen learnt the art, and have since
brought it to the greatest perfection.
Scagliola is a composition of plaster of Paris and earthy colors, or any colors
which will withstand the action of an alkali. In its manufacture, the ground or
predominating color is first mixed to the desired tint, and the other colors intend-
ed to be introduced must be mixed separately, with a portion of clear size, and a
little spirits of turpentine, to facilitate the drying.
If, in the marble intended to be imitated, the colors blend gradually into each
other, as in Sienna and the others generally executed, the imitation must be
formed while the colors are in a soft state, by putting the ground mixture into a
large trough, and adding the different colors in a proportion and a taste which can
alone be acquired by experience.
If, on the contrary, the distinction between the colors is strongly marked, the
secondary colors must be allowed to set nearly hard, broken into small pieces,
and added to the ground mixture, which must be kepi in the trough in a soft
state, as before mentioned.
SECTION XVIII. — Manner of forming Columns or Pilasters in Scagliola.
When the architect has furnished the drawing exhibiting the diameter of the
shaft, a cradle is made of wood about two and one half inches less in diameter
than the projected column. The circumference of this cradle being lathed with
double laths, as in common plastering, must be covered with a pricking-up coat
of plaster, gauged with very thin size, in order to harden it.
The pricking-up coat, after being completely set, must be well soaked with
72
PRACTICAL MASONRY.
water. The composition must be then taken from the trough, flattened into
cakes about eight inches square, applied to the column, and well beat on with a
wooden beater and small gauging-trowel. In this state it must remain until per-
fectly dry, when the protuberances may be taken off, with a plane. The column
must then be put in the lathe and turned to the size required. This operation
being finished, it will have a porous appearance, which must be obviated by the
application of a thick wash, and scraping it with steel scrapers until it assumes
the surface of real marble, when it will be fit for polishing, which must be effect-
ed by first using pumice-stone, at the same time cleansing it with a wet sponge,
and afterwards with Tripoli powder and charcoal. After going over the whole
with a piece of white glove-leather, dipped in a mixture of Tripoli powder and oil
of olives, the process must be finished by the application of pure oil.
White scagliola is simply a mixture of plaster of Paris and mineral green, the
manner of using it being the same as above described.
SECTION XIX. — Modelling for Stucco or Plaster of Paris.
The whole of the ornaments cast in plaster of Paris are previously modelled in
clay, which method has of late years almost entirely supplanted the process of
working the ornaments in their places by hand.
Large works, such as angle-pieces and foliage for ceilings, require more judg-
ment than enriched mouldings, such as ogees or ovelos, sthe eye of the model-
ler in the former case being his only guide, whereas, in the mouldings, the com-
passes are found of essential service. For example, in the moulding of an
ogee, only one of the divisions is required to be modelled in clay, which may be
effected by procuring a templet exactly corresponding with the profile of the
moulding, and running a small portion of the moulding out with it in clay, in
a small case of wood adapted to the purpose. The design of the ornament is
then marked on the clay, and moulded to its peculiar form by the use of tools
made of ebony and box, and finely polished with brass tools. When finished in
the modelling, it is moulded in wax, and a sufficient number cast and fixed
together to a length varying from eight inches to one foot, and afterwards cleaned
up and corrected with steel and brass tools. This piece of ornament, after being
properly corrected, is called the original, as an unlimited number of moulds may be
taken from it. In moulding angle-pieces it is necessary to run out a sufficient
quantity of the plain moulding in putty and plaster to the exact form of the angle.
The embellishments are then modelled on the mouldings, and also moulded there-
OF THE MOULDING OF ORNAMENTS.
73
on, the mouldings forming a ground for the ornaments, so that, after being cast,
they will exactly fit the mouldings when fixed in their proper situations on the
ceiling.
SECTION XX Moulding of Ornaments.
There are two methods of moulding practised by plasterers, namely, moulding
in wax and moulding in plaster ; the former is applied to all kinds of cornice en-
richments, as friezes, soffits, ogees, ovolos, &c., and also to centre-flowers and
angle-pieces; the latter is generally employed for works of large dimension,
which, from the manner in which they are under cut, are not easily cast in wax
moulds, as coats of arms, trophies, and plain capitals attached to trusses ; it may
also be applied to works in Roman cement, such as balustrades, heads, &c. In
moulding in wax, the clay model must, in the first place, be well oiled with sweet
oil, and a fence of clay put round it, to prevent the liquid wax from escaping, after
which a sufficient quantity of wax and rosin must be dissolved together, which,
when lukewarm, must be poured over the model, until it is completely covered.
When the wax is sufficiently set, the whole must be immersed in water, which
will cause it to leave more readily ; after which, the clay being all washed out of
the mould, it will be fit for casting in.
This method will be found sufficient where a face mould only is required, but
when what is termed a back-and -front is wanted, as is the case in all leaves for
centre-flowers, it is requisite to cut the front plaster-cast back, so that the ruffling
will show distinctly, and afterwards to soak it in water. The leaf must then be
backed up all round, within one sixteenth of an inch of the edge, with a sub-
stance of clay, an inch wide, in which rivets must be inserted. The leaf being
freed from all particles of water which may remain on the surface, the clay must
be well oiled. A fence of clay is then put round the whole, and the wax poured
on, which, after remaining until quite hard, must be turned upside down, and the
clay all removed from it, when the wax must be oiled or the whole brushed over
with a little liquid clay. Another quantity of wax must be prepared, and, when
almost cold, poured over the first, which will form the back mould ; a fence of
clay being provided, is put round to prevent the wax from escaping. When this
mass is sufficiently set, the two parts may be disunited, and the plaster-leaf re-
moved, thus forming two moulds, the one for casting the back, and the other the
front of the leaf. This manner of moulding is also used for all kinds of foliages
which need much relief.
10
74
PRACTICAL MASONRY.
SECTION XXL — Moulding in Plaster.
Ijv moulding in plaster, the same as in wax, the clay model must be oiled with
sweet oil, but the plaster must be laid (not too soft) by one piece at a time, form-
ing the joints, and fitting them to each other, in such situations as the skill of the
workman may suggest. After having completely covered the model with pieces,
the whole must be removed, and, when perfectly dry, soaked in boiled linseed oil.
The various parts of the mould, being well saturated with oil and quite dry, are
fit for use, and may be oiled, ready for casting, with sweet oil, in the same man-
ner as wax moulds.
Casting in Plaster. The moulds being prepared and properly cleansed, are
oiled in the way above mentioned. A sufficient quantity of plaster of Paris, being
mixed with water to a semi-fluid state, is well dubbed into the mould with a
small brush, which, after remaining a short time, is floated off flush with the rim
of the mould. The plaster being set, the impression is taken from the mould by
means of pressing the wax gently with the hands all round, the heat of the plas-
ter causing the mould to yield. The ornaments, after being taken from the mould,
are cleaned up and cut with a trimming-knife to the proper joints, ready for the
workman to fix in the places intended for their reception.
Friezes and basso-relievos should always be cut with a half-inch ground at
their backs, which serves to strengthen and secure their proportions.
SECTION XXII. — Fixing Ornaments.
When the enrichments about to be fixed are small in size, they may be fixed
in the grooves or indents prepared for them with putty well gauged with plaster;
but when the ornaments are of a weighty description, it becomes necessary to
use fine stuff", and to cut away the plain surface of the work as far as the lathing.
The place so cut away is then filled with gauged fine stuff", and the cast, being
well scratched on the back in the form of a dovetail, must also have a portion of
fine stuff" laid on it when it is placed in its proper position, and pressed to the
work, so that they may both incorporate. When the ornaments are extremely
heavy, such as coats of arms and shields, in addition to the above mode, it is in-
dispensably necessary to have recourse to large screws, which must pass through
the cast work into the timber.
OF STUCCO CORNICES.
75
SECTION XXIII. — Stucco Cornices.
Previous to the operation of forming the cornice, it should be the practice of
the plasterer to examine the drawings, before the preparation is made for the
pricking-up coat. When the projection does not exceed seven or eight inches, it
is the practice, in filling in or blocking with coarse stuff, as common plastering
mortar, to fill within one half or three quarters of an inch of the mould, and leave
it as rough as possible for the putty to adhere to; but in case the cornice should
project eight inches or over, it is best in most cases to bracket the angle of the
ceiling. First fit a piece of pasteboard so as to conform to all the members of a
section of the drawing, on the outside of the projections. The pasteboard may
be pasted on to a thin plate of metal, of iron, copper, or steel, and by the means
of files, &c., is fitted to the details of the mouldings cut out from the pasteboard.
A piece of wood is fixed to the metallic mould about half an inch thick, so bev-
elled as not to clog in the moulding of the cornice, leaving the edge of the mould
or metallic part to project about one half or one quarter of an inch from the wood
backing. On the top and bottom part of the mould are attached two slides of
wood, to keep the mould in a proper position on the screeds, and at a right an-
gle with the wall ; and sometimes a mould is made for the using of coarse stuff,
which is about one eighth of an inch smaller in all of its members than the afore-
mentioned mould. Bracketing is formed of inch -boards, so as to fall three quar-
ters or one inch within the general projections of the aforesaid mould, and fastened
up about one foot apart, and properly latbed, and covered with a coat of coarse
stuff. The cutting of moulds being completed, the ceiling and walls floated and
levelled, the projection of the cornice must be lined on tbe ceiling, and also its en-
croachment on the wall. At each line of projection, narrow screeds must be made,
with a very thin coat of strong gauged fine stuff, and perfectly smoothed wdth
the floating-rule. In the making of these screeds, much pains must be taken, as
the correctness of the cornice depends upon the precaution used in their formation.
The running rules properly adjusted on a straight line, wooden strips about
three inches wide and one half an inch thick nailed upon the protruding line on
the wall, which has been done round the room for the purpose of directing the
mould in forming the cornice, — the aforesaid preliminaries being attended to, it is
fitted for running.
Running the Cornice. Two workmen and a boy are required, one to lay on the
stuff, and the other to work the mould. The hawk-boy commences gauging the
76
PRACTICAL MASONRY.
coarse stuff, which at first must be gauged ; one of the workmen takes a portion
of it on his hawk, and plasters a part of it on the place where the cornice is to be ;
the other workman begins, by moving the mould backward and forward, holding
it firmly to the ceiling and wall, thus removing the superfluous stuff ; this opera-
tion is continued until the cornice is as perfectly formed as can be with the coarse
stuff. The putty and plaster is then gauged, and the same process pursued as in
the coarse stuff, using the fine mould, adding gauged stuff until the exact contour
of the cornice is formed.
When the cornice is very large, it may be best to run it by using two small
moulds ; one below, forming the plainer face and bed mouldings, and the other
part forming the crown mouldings, &c.
The mitres internal and external, as well as breaks or small returns, are
formed afterwards by hand, wuth small tools for the purpose.
SECTION XXIV. — Circular and Elliptical Cornices or Mouldings.
This kind of cornice requires much more labor than straight ones, but the
principal operation is the same, except that when they are circular they must be
run from a centre, by means of w'hat is called a gig-stick, to which the mould is
attached ; a hole being bored in it exactly to the radius, w^hich fits to a pin placed
exactly in the centre of the circular moulding. When the mouldings are to de-
scribe an ellipsis, the most correct method is to run them from a trammel, such
as is used by carpenters.
SECTION XXV. — External Compositions.
Within the last fifty years, great improvements have been made in the art
of plastering by the invention of various compositions for the covering of the ex-
teriors of buildings, such as Roman cement, terra cotta, mastic, and Bailey’s com-
position.
These compositions are susceptible of being applied both to the finishing a
plain surface to be jointed to imitate stone, and in the formation of ornaments of
every description. On account of their cheapness, they have given rise to design
and much architectural display, w^hich heretofore w^as not thought of.
The careful study of the antique examples of architecture, both in Greece
and ancient Rome, has also acted as a pow^erful stimulus to the promotion of the
OF EXTERNAL COMPOSITIONS.
71
art of design, as well as ornamental plastering ; more particularly in the getting
up of Greek and Roman capitals, the former of which were, until within the last
few' years, scarcely known in Europe ; and the latter have been most essentially
improved by reference to the casts procured from the original, now^ extant.
The invention of composition has, no doubt, been facilitated by the scarcity of
good stone in the south part of Great Britian. Other parts and other countries
availing themselves of these improvements, have, in many instances, been led
to farther study in the arts, and it operates as a stimulus to the taste for
ornamental decorations and is of great utility to the public interests of this coun-
try, although probably no nation in the w'orld possesses a greater variety of useful
building materials than the United States of America.
Roman Cement or Compo was first introduced to public notice by the late
James Wyatt, Esq. It was originally known as Parker’s patent cement, but there
is a much superior article prepared from the stone discovered by William Atkin-
son, Esq., on the estate of the Earl of Mulgrave, known by the name of Atkinson’s
cement. At the first, it costs a little more than the Roman cement, but it w'ill
bear a great deal more sand than the former, is of a more delicate stone color,
and for situations constantl}^ exposed to the action of water it is not surpassed by
any cement now’ in existence.
Roman Cement is prepared from the kind of stone called clay-balls, or septaria,
by being, after the manner of manufacturing plaster, first broken into pieces of a
convenient size, slowly calcined in kilns or ovens, and afterwards ground to a
fine pow’der, and put into proper casks. Two parts of composition, wdth three
parts of clean grit sand, will form a very durable substitute for stone. In select-
ing the sand, great care must be taken to procure it possessing qualities of a sharp
and binding nature, free from clay or mud. If it cannot be had free from these,
it must be washed pei’fectly clean in fresh water.
After the walls intended to be covered have been w’ell soaked with water, the
cement must be prepared by the haw'k-boy on a board made for the purpose, add-
ing as much water as brings it to the consistency of paste. No more must be
mixed than can be used in ten minutes. It must be laid on with the greatest ex-
pedition, in a coat of three fourths of an inch thick. After being well floated by
means of the floating-rule, the hand-float must be incessantly used to bring it to
a firm and solid surface before it sets, wdfich takes place within fifteen minutes if
the cement be good.
After the w’ork has been drawn and jointed to imitate w’ell-bonded masonry, it
may be colored wdth a wash composed of five ounces of copperas to every gallon
of water, mixed w’ith a sufficient quantity of fresh lime and cement, adding the
colors necessary to produce an exact imitation of any particular stone which may
78
PRACTICAL MASONRY.
be required. When this mode of coloring is executed with judgment, and finish-
ed with taste, so as to produce a picturesque effect, by touching the divisions
with rich tints of ochre, umber, &c., it is with difficulty distinguished from real
stone. It has been attempted, and in some cases very successfully, to produce
ancient Gothic ruins in cement, and although, to consummate the deception, great
skill and judgment are required, yet we have no doubt that, by paying proper
attention to the style of architecture, as well as the manner of coloring, imitations
of tliis kind might be carried to great perfection.
Terra Cotta is an excellent as well as durable composition, made use of at
the present day very advantageously for all kinds of exterior decorations. It is a
composition of pipe-clay, stone bottles, glass, and flint, well pounded together,
and sifted through a very fine sieve, a small portion of silver sand being afterwards
added. The above ingredients must first be well mixed in a dry state, and then
water added to reduce them to the pliability of moulder’s clay. The mixture thus
formed, having remained in this state for two or three days, must be beat or tem-
pered in a similar manner to moulding clay, after which it is fit for use.
When applied to capitals, the bell or cover must be prepared not more than
two and a half inches thick, the stuff of which it is composed being of a coarser
nature than that used for its embellishments. After the ornaments, as the leaves,
volutes, &.C., have been modelled, they must be moulded in plaster, and squeezes
of artificial stone taken from the moulds, well cleaned up with appropriate tools,
and fixed to the bell. It is necessary, when the ornaments are fitted, to bore two
or three holes, three fourths of an inch in diameter, on those parts of the bell where
the enrichments are to be placed, in order to let the damp air escape in the process
of burning.
To fix the ornaments, procure some of the dry composition, and let it remain in
water about one day, then take out the portion that remains at the bottom, which,
being well chafed on a hawk, composes the stuff for fixing.
After the bell and the back of the enrichments have been well wrought, a little
soft stuff is rubbed on each, and the ornaments attached to the bell in the usual
way.
The capital being then in a fit state for drying, must be left in the open air for
that purpose, and, when thoroughly dried, placed in the kiln, which is composed of
the same materials as a common oven, but of a somewhat different construction,
as the flue must extend entirely over the covered ceiling of the kiln, and be per-
fectly clear of the ornament.
In the burning of terra cotta, it is necessary to commence with a very slow
fire, gradually increasing it for the first week, after which a brisk fire must be
kept up for three days and nights without intermission. The front of the kiln
OF EXTERNAL COMPOSITIONS.
79
must then be closed with an iron plate, to prevent the ingress of the atmospheric
air. Having remained three days in this situation, it is considered sufficiently
burnt, and the kiln must be gradually opened, as the sudden admission of the air
will cause the ornaments to crack or splinter.
Method of moulding Terra Cotta. The models being executed in clay,
as is usual in moulding plaster ornaments, they must be moulded in the same
manner as figures and busts, with this difference, that the clay must not be
oiled, nor the joints of the plaster-pieces which compose the mould. Instead
of oiling the model, it is washed with pure water, when the moulder may
commence his operations. The various joints of the plaster-pieces in the
mould must be touched with a small brush containing a little liquid clay
(instead of oil, which is the general method), and great care taken in the forma-
tion of the different joints, as the pieces cannot be taken from the model
to be cut and fitted, but must all be brought to their proper shapes while
they remain on it. When the sufficient number of pieces are made, so as to
completely envelope the model, a case of plaster must be put over the whole. In
taking the form of the model, it is requisite to soak the whole in water, in order
that they may leave the more readily, which being done, the mould must be well
washed and put into the case and gradually dried in the air, when it will be fit
for use without the process of seasoning in oil, as is customary in casting in
plaster from a plaster mould. .
Manner of procuring Impressions from the Mould in Terra Cotta (sometimes i
called Squeezing). The mould being dry, the workman must take a little of
the finer stuff in his hands, and press a thin coat over the whole of the face of the
mould, adding on the back that of a coarse quality, rubbing in small portions at a
time, so that the ornament may be firm and solid. Immediately after squeez-
ing, the ornament must be taken from the mould, cleaned up, and fixed in its
place. When the mould has been used two or three times, it is liable to become
damp, which prevents the impressions from leaving expeditiously ; in this case,
for the purpose of destroying its adherence, sprinkle a little fine flint-dust into the
mould. These methods of moulding and casting may be applied not only to
capitals, but also to all kinds of work in this composition, such as coats of arms,
vasCs, foundations, figures, and busts, always taking the precaution never to
allow the substance of artificial stone to exceed tw^o inches and one half. For
any greater thickness will be liable to injure in burning.
Mastic is intended for an external composition, possessing peculiar properties,
which in some cases render it superior to Roman cement, having the power of
resisting heat and frost, adhering to iron, copper, and even glass, with equal
tenacity.
80
PRACTICAL MASONRY.
It is generally applied to the exteriors of mansions, but it may also be very
beneficially used for laying the floors of halls, kitchens, &,c.
Mastic is composed of pounded stone, silver sand, litharge, and red-lead,
and when manufactured has the appearance of very fine sand. It will be perceiv-
ed the manner of working mastic is entirely different from that of Roman cement.
To one hundred-w^eight of mastic add one gallon of linseed oil, and let them
be well incorporated, which must be effected by treading them together with
the feet until the amalgamation is complete, and must be continued until all the
bright spots disappear ; it will then be fit for use.
The Manner of using Mastic. The joints of the brick-work being well
cleaned out, the work must be correctly plumbed up by means of flat-headed
nails, and screeds for the guidance of the floating-rule formed with Roman cement,
and kept about one inch in breadth. This being done, the bricks must be well
saturated with boiled linseed oil of the best quality, and the mastic laid on with
the hand and laying-trowel. The floating-rule is then passed carefully over the
work, and when the space between the screeds is sufficiently filled up. it must be
floated with a hand-float until it assumes the appearance of highly polished
stone, the screeds then cut out, their places filled with mastic, and properly trow-
elled into the rest of the work.
These directions will be proper for large works, but where windows and
doors occur, it will be necessary to attach strips of wood on to the reveals
to project the thickness of the intended mastic-work, and when the preparations
for forming the reveals by shifting the strip of wood to the outside of the plaster-
ing, projecting as before to guide the hickness of the reveals. When well trow-
elled the strips are taken off and nail-holes filled, and angles well cleaned down.
Thus this process is completed.
To run Mastic Mouldings. In order to run mouldings with mastic, a mould
of wood must be cut, in every way three eighths of an inch less than the intended
moulding, the ground or inner part of the moulding being formed of pieces of
broken bricks or tiles, and with the wooden mould run out with Roman cement
and afterwards with mastic, the mastic mould being cut to the full size, the
edges mounted with brass, iron, or copper. All ornaments executed in mastic
must be cast in plaster-moulds similar to those used in figure-casting, with-
out being seasoned in oil, but used in their dry state, and kept well pol-
ished with a linen cloth. All heavy ornaments for soffits and entablatures
should be cut through the plastering to the brick-w'ork in a dovetail form some-
thing less than the figure, and as many nails as convenient driven in the back
of the figure, and the hole filled with Roman cement in a soft state, then the
figure properly adjusted in its intended place. All small enrichments may be
set with white-lead.
OF EXTERNAL COMPOSITIONS,
81
Mastic Floors. The groundwork being completely dry, and the bricks
properly cleaned and saturated with boiled linseed oil, the screeds formed with
Roman cement, for the purpose of floating or levelling, the mastic mortar between
the screeds being about one half of an inch thick, then cut out the screeds and
fill their places with mastic, and trowel it down level with the other work.
Bailey’s Composition. This composition is a valuable invention, of recent
date, and may be used with great advantage, without being injured by the action
of frost, on the exterior of public or private buildings. This is composed of un-
slacked lime well ground to a fine powder, and kept in air-tight casks until used.
It is prepared by adding one third of sharp and clean river-sand. Reduce it by
clean water in the manner of preparing Roman cement.
11
82
PEACTICAL MASONEY.
CHAPTER III.
PRACTICAL GEOMETRY, ADAPTED TO MASONRY AND STONE-CUTTING.
SECTION L — On the Position of Lines and Points.
As the construction of every complex object in nature consists of certain
combinations of the simple operations of geometry, and as positions cannot be
understood without angles and parallel lines, it will be necessary to treat of the
practical part of this science, at least as far as the operations of the positions
of lines and points are concerned, in order to render the construction and the
language of geometry familiar to the student in their applications to the princi-
ples of masonry.
PROBLEM I.
From a given point in a given straight line to draw a perpendicular.
Plate I. Let AB,^g-. 1, be a given straight line, and c the given point. In
AB take two equal distances, cd and c e. From d, as a centre, with any radius
greater than cd or c e, describe an arc at f, and with the same radius, from the
point e, describe another arc intersecting the former at /, and draw /c, and /c is
the perpendicular required.
PROBLEM II.
From the one extremity of a straight line to draw a perpendicular.
Fig. 2. Let AB be the given straight line, and let it be required to draw a
perpendicular from the extremity B. On one side of the line A B take any con-
venient point c ; and from c, as a centre, with any radius that will cut the line,
describe an arc d B c, intersecting A B in the point d ; through c draw the di-
ameter d e, and join e B, and e B is the perpendicular required.
PROBLEM III.
From a given point out of a straight line to let fall a perpendicular.
Fig. 3. Let A B be the given straight line, and c the given point ; it is re-
quired to draw a straight line from c, perpendicular to A B. From c, as a centre,
with any distance that will cut the line A B, describe an arc intersecting A B in
the points d and e ; from d, as a centre, with any radius greater than the half of
/V. 1 .
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ON THE POSITION OF LINES AND POINTS.
I
83
de, describe an arc, and from e, with the same radius, describe another arc inter-
secting the former in f, and draw / c, and fc is the perpendicular required.
The criterion of the truth of the method of Jig. 2 is that of the angle in a
semicircle being a right angle.
PROBLEM IV.
At a given point in a given straight line, to make an angle equal to a given
angle.
Fig. 4. Let C B A be the given angle, and E F the given straight line. Let
it be required to draw a straight line, at the point E, to make an angle with the
line E F, equal to the angle C B A. From the point B, with any radius, describe
an arc meeting BA in A, and B C in g- ; and from the point E, with the same
radius, describe an arc ik, meeting E F in i. IMake ik equal to gh, and through
k draw the straight line E D, and F E D is the angle required.
PROBLEM V.
Through a given point f to draw a straight line parallel to a given straight
line A B.
Fig. 5. Let /be the given point, and AB the given straight line. Draw any
straight line /e, meeting A B in c, and draw g/t, making the angle A^B equal to
/cB. Make gk equal to e/. Through the points / and A draw the line C D,
and C D is parallel to A B, as required.
PROBLEM VI.
To draw a straight line parallel to a given straight line at a given distance
from the given straight line.
Fig. 6. Let A B be the given straight line ; it is required to draw a straight
line at a given distance from B C. In A B take any two points e and f ; from e,
with the given distance, describe an arc g A ; and from / with the same distance,
describe another arc ik. Draw the line C D to touch the arcs gh and ik, and
C D is parallel to A B, as required.
PROBLEM VII.
To bisect a given straight line A B by a perpendicular.
Fig. 7. From the point A, as a centre, with any radius greater than the half
of AB, describe an arc cd; and from B, with the same radius, describe another
arc intersecting the former at c and d, and draw c d, intersecting A B in e ; then
A B is divided in e, as required. •
84
PRACTICAL MASONRY.
PROBLEM VIII,
Upon a given straight line to describe an equilateral triangle.
Fig. 8. Let A B be the given straight line. From the point A, with the ra-
dius A B, describe an arc, and from the point B, with the radius B A, describe
another arc, intersecting the former in C, and draw the straight lines C A and
C B , then A B C is the equilateral triangle required.
PROBLEM IX.
Upon a given straight line to describe a triangle, of which the sides shall be
equal to three given straight lines, provided that any one of the three given
lines be less than the sum of the other two.
Fig. 9. Let the three given straight lines be A, B, C, and let D F be the
straight line on which the triangle is required to be described. Make D F equal
to the given straight line A. From D, with the radius of the line B, describe
an arc, and from F, with the radius of the line C, describe another arc, meet-
ing the arc described from D in the point E. Draw E D and E F, then DE F
is the triangle required.
PROBLE.M X.
Given the base and height of the segment of a circle, to find the centre of
the circle, and thence to describe the arc.
Fig. 10. Let A C be the base ; bisect A C in D by the perpendicular B E ;
make D B equal to the height, and join the points A and B. Make the angle
B A E equal to A B E, and the point E is the centre required.
From the point E, with the radius E A or E B, describe the arc AB C ; then
A B C is the arc required.
N. B. The centre must also have been found by bisecting AB by a perpen-
dicular, which would have met B E in the point E.
PROBLEM XL
Given two converging lines, through a given point in one of them to draw a
third straight line, so that the angles on the same side of the line thus drawn, made
by this line and each of the first two given lines, may be equal to each other.
Fig. 13. Let the two converging lines be A C and B D, and let A be the
given point. Draw A E parallel to B D ; bisect the angle CAE by the straight
line A B ; then will the angles CAB and D B A be equal to one another.
For, suppose A E .to be produced from A to F, and suppose A C and B D to
be produced to meet in some point G, then A C would have been a line falling upon
ON THE POSITION OF LINES AND POINTS.
85
the two parallel straight lines A F and B D, and consequently making the angle
at G equal to the angle FAC; and since the three angles of every triangle are
equal to two right angles, and since the angles F AC, CAB, BA E, are also equal
to two right angles, and since F A C is equal to the vertical angle of the triangle,
the angle C A E is equal to the sum of the angles at the base ; and therefore,
since C A B is half the sum, the angle A B D must be equal to the other half.
PROBLEM XII.
Given two converging lines, to describe the arc of a circle through a given
point in one of them, without having recourse to a centre, so that the point of
convergency may be in the centre of the arc.
Fig. 14. Let AB and E F be the two converging lines, and A the given point
through which the arc is to pass. Draw AE, making the angles BAE and FEA
equal to each other. Bisect A E by the perpendicular C D, and draw A h mak-
ing the angles BAA and DAA equal to one another ; then A A is the chord of the
arc, and nA is the versed sine. Suppose now that the three points A, A, E, are
transferred to A, B, C,fig. 15. Join B A and B C. Produce B A to c?, and B C
to e. Make the edge of a slip of wood to the angle d B e. Move the edge d^e
of the slip of wood so that the point B may be upon A ; then move this slip
again, so that while the part B d of the edge of the slip is sliding upon the pin
at A, and the part B e upon the pin at C, a pencil held to the angle B will de-
scribe a curve ; then this curve will be the arc required.
PROBLEM XIII.
Given two straight lines, to find a third proportional.
Fig. 1 1. From any point A, draw any two straight lines B A, A C, at any an-
gle. Make A B equal to one of the given straight lines, and A C equal to the
other ; and in A B make A d equal to A C. Join B C and draw d e parallel to
B C, meeting A C in e ,* then A e is the third proportional required.
^ Or, if A e be equal to one of the given straight lines, and A d equal to the
other. Make A C equal to A d. Join d e and draw C B parallel to ed ; then A B
is the third proportional.
, PROBLEM XIV.
Given a straight line, and how divided, to divide another in the same propor-
tion.
Fig. 12. Draw the lines B A, A C, as in the preceding problem, and let A B be
the given divided line, d and e being the points of division, and let A C be the
line to be divided. Join B C and draw eg and df parallel to B C, meeting A C
86
PRACTICAL MASONRY.
in /and g ; then A C is divided in f and g, in the same proportion as A B is di-
vided in the points d and e.
PROBLEM XV.
Given three straight lines, to find a fourth proportional.
Fig. 12. The angle BAG being made as before, let Ae be equal to one of
the given lines, A d equal to a second, and A f equal to the third. Join d f and
draw eg parallel to df; then A^ is the fourth proportional.
SECTION II. — On the Species, Nature, and Construction of Curve Lines.
The geometrial orders of lines employed in architecture, in the construction
of arches, are circular and elliptic, and occasionally parabolic, hyperbolic, cycloid-
al, and catenarian curves.
In houses, the chief lines employed in the construction of arches and vaults
are circular and elliptic curves, generally a semi, and sometimes less, but seldom
or never greater. When a circular or elliptic arc is adopted, one of the axes of
the curve is most frequently situated upon the springing line ; but is sometimes
placed so as to be parallel to it. The most usual portions of circular or elliptic
curves are the semi ; and in the pointed style of architecture, parabolic and hy-
perbolic curves are very frequently employed.
In bridge building, besides circular and elliptic curves, which are the most
often used in the construction of stone arches, cycloidal curves may also be in-
troduced. In chain bridges, or bridges of suspension, not only the circular and
parabolic curves, but that of the catenarian may be employed. The suspending
chains necessarily assume the form of catenarian curves ; but the road-way may
be any curve line whatever ; but as all curves are nearly circular at the vertex,
it will be better to employ those in the construction of works which are suscepti-
ble of the most easy calculation.
Among the numerous orders of curve lines, the parabolic affords the most
easy means of computing its ordinates and tangents, which will be found neces-
sary in ascertaining the rise and inclination of the road-way in all points of the
curve, from either extreme to the centre of the bridge.
The base of an arc is that upon which the arc is supposed to stand ; and the
highest point of an arc is that in which a straight line parallel to the base would
meet the curve, without the possibility of coming within the area included by
the curve and its base, and this point is called the summit of the arc.
As the curves employed in building are generally symmetrical, therefore they
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OF CURVED LINES.
87
are equal and similar on each side of the summit, and their areas are equal and
similar on each side of the perpendicular from the middle of the base.
PROBLEM I.
To describe a semi-ellipse upon the transverse axis.
Plate II. Let A a, Jig. 12, be the axis major, and let B C, bisecting A a per-
pendicularly in the point C, be the semi-conjugate axis.
Upon the straight edge m i of a rule, mark the point 7n at or near one of its
ends, and the point / at a distance from m equal to B C, the semi-conjugate
axis, and the point k at a distance from m equal to AC or C a, the semi-
transverse axis ; the distance k I being equal to the difference of the two axes.
To find any point in the curve, place the point k in the line B C produced, and
the point / in the axis A a ; and mark the paper or plane on which the figure is
to be described at the point m. Proceed in this manner until a sufficient num-
ber of points are found, and draw a curve through them, and the curve will be
the semi-ellipse required.
PROBLEM II.
Upon a given double ordinate, to describe the segment of an ellipse to a
given abscissa, and to a given semi-axis in that abscissa.
Figs. 13 and 14. Let M m be the double ordinate, P H the abscissa, and H C
the semi-axis.
Through the centre C, draw KA' parallel to IVlwi. From either extremity m of
the double ordinate as a centre, with the distance H C of the given semi-axis as
radius, describe an arc intersecting K k in r. Draw ?n r intersecting H C in or
produce mr and H C to meet in q ; then m q,Jig. 13, will be the semi-transverse,
and mr the semi-conjugate, and in Jig. 14, the contrary will take place; mr will
be the semi-transverse, and m q the semi-conjugate ; the two axes being thus
found, the curve may be described as in the immediately preceding problem.
PROBLEM III.
Given two conjugate diameters, to find any number of points in the curve,
and thence to describe it.
Figs. 15 and 16. Let A a, BZ», be the conjugate diameters. Draw AD
parallel to B C, and B D parallel to C A. Divide A D and A C each into the
same number of equal parts. Through the points of division in A C draw
straight lines from b, and through the points of division in AD, draw other
straight lines to the point B, meeting those drawn from b in the points /, g, h.
88
PRACTICAL MASONRY.
Draw a curve line through the points A, f, g, h, B, which will be one quarter of
the whole figure. The other three will of course be found in the same manner.
PROBLEM IV.
To draw a normal, or line perpendicular to the curve of an ellipse at a given
point in the curve.
Fig. 17. Let the curve be A B «, and let A a be the transverse axis, and
C B the semi-conjugate, and let it be required to draw a line from the point 71
perpendicular to the curve. With A C the semi-axis major as a radius, from
the point B describe an arc, intersecting A a in the foci . From the points
and through the point n, draw/'^/ and /e, and bisect the angle end, and
the bisecting line 11 N will be perpendicular to the curve as required.
PROBLEM V.
To draw a tangent to the curve of an ellipse at a given point.
Fig. 17. Let m be the given point. Draw fm, and produce fm io g, and
join the points /', m. Bisect the angle f'mg, and the bisecting line T t will
be the tangent required.
PROBLEM VI.
The curve of an ellipse being given, to find the two axes.
Fig. 18. Let AMN^im be the given curve within the figure; draw any
two parallel lines Mm, N;i. Bisect Mm in 0 , and N in p, and draw the
straight line A op a. Bisect Aa in C, from C as a centre, with any radius that
will cut the curve ; describe the arc rr', intersecting the curve in the points rr\
and draw the straight line rr'. Bisect r r' in /i, and through the points A and
C draw the line de, then de is the axis major; and a line drawn through the
point C at right angles to d e, to meet the curve on each side of C, will be the
axis minor.
PROBLEM VII.
With a given abscissa and ordinate, to describe a parabola."
Fig. 19. Let AB be the abscissa, and B C the ordinate. Draw CD paral-
lel to B A, and A D parallel to B C. Divide C D and C B each into the same
number of equal parts. From the points 1, 2, 3, in C D, draw lines to A, and
from the points 1, 2, 3, in C B, draw lines parallel to BA, meeting the former
lines to A in the points /, g, h. Draw the curve C fg h A, which will be one
half of the parabola ; the other half will be found in the same manner. The
radius of curvature at the point A is half the parameter.
OF LINES AND PLANES.
89
PROBLEM VIII.
The curve of a parabola being given, to find the parameter.
Fig. 19. Let C AN be the curve of the parabola. Bisect B C in the point
2, and draw A 2 and 2 d perpendicular to A 2, meeting A B produced in d ; then
B d is one fourth part of the parameter.
For A B : B 2 : : B 2 : B d; now let A B = «, B C = 6, then B 2 = ; hence
a : j b :: Y h : i p; whence ap = F ot p —
PROBLEM IX.
To draw a tangent to any point M, in the curve of a parabola.
Fig. 1 9. Draw the ordinate P M, and produce P A to Make A q equal
to A P, and draw the straight line q IM ; then q M will be the tangent required.
For the subtangent of the curve is double to the abscissa.
PROBLEM X.
To form the curve of a parabola by means of tangents.
Fig. 20. Let A C be the double ordinate. Draw D B bisecting A C, and
make D B equal to the abscissa. Produce D B to E, and make B E equal to
B D. Draw the two straight lines E A and E C. Divide A E and E C each in
the same proportion, or into the same number of equal parts, at the points 1, 2, 3|^
&,c., in each line. Draw the straight lines 1-1, 2-2, 3-3, &c., and their intersec-'^
tions will circumscribe the curve of the parabola as required.
Scholium. Small portions of the curves of conic sections, near to the vertices,
may be described with compasses so as not to be perceptible ; and thus, not
only in the parabola, but in the ellipse ; and in the hyperbola, the radius of curva-
ture at the vertices is half the parameter, which passes through the focus. In
the parabola, the parameter is a third proportional to the abscissa and ordinate ;
and in the ellipse and hyperbola, the parameter is a third proportional to the
transverse and conjugate axis ; and therefore may be easily found by lines or by
calculation on large works, such as bridges, &.c.
SECTION III. — Of the Position of Lines and Planes, and the Properties arisino
FROM their Intersections.
A PLANE is a surface in w^hich a straight line may coincide in all directions.
A straight line is in a plane, when it has two points in common with that
plane.
12
90
PRACTICAL MASONRY.
Two straight lines which cut each other in space, or would intersect if pro-
duced, are in the same plane ; and two lines that are parallel are also in the
same plane.
Three points given in space, and not in a straight line, are necessary and
sufficient for determining the position of a plane. Hence two planes, which have
three points common, coincide with each other.
The intersection of two planes is a straight line.
Plate I. When two planes AB C D, A B E F, jig. 16, intersect, they form
between them a certain angle, which is called the inclination of the two planes,
and which is measured by the angle contained by two lines ; one drawn in each
of the planes perpendicular to their line of common section.
Thus, if the line A F, in the plane A B E F, be perpendicular to A B, and the
line A D, in the plane A B C D, be perpendicular also to A B, then the angle
FAD is the measure of the inclination of the planes A B E F, A B C D.
When the angle FAD is a right angle, the two planes are perpendicular.
Fig. 1 7. A line A B is perpendicular to a plane P Q, when the line A B is
perpendicular to any line B C, in the plane P Q, which passes through the point
B, where the line meets the plane. The point B is called the foot of the per-
pendicular.
A line A ^,fig. 18, is parallel to a plane P Q, when the line A B is parallel to
another straight line C D, in the plane P Q.
If a straight line have one of its intermediate points in common with a plane,
the whole line will be in the plane.
Two planes are parallel to one another when they cannot intersect in any
direction.
The intersections of two parallel planes with a third are parallel. Thus, in jig.
19, the lines A B, C D, comprehended by the parallel plane P Q, RS, are par-
allel.
Any number of parallel lines comprised between two parallel planes are all
equal. Thus the parallel lines A a, B 6, C c, . . . ., fig. 20, comprised by the
parallel planes P Q, R S, are all equal.
If two planes C D E F, G II I fig. 21, are perpendicular to a third plane P Q,
their intersection A B will be perpendicular to the third plane P Q.
If two straight lines be cut by several parallel planes, these straight lines will
be divided in the same proportion.
N
PI J.
:ii !l 1 1:1 'i‘ 8 K K 'I W S iD) J'* AiRV III K 3.
W7 S'c.
OF THE RIGHT SECTIONS OF ARCHES.
91
SECTION IV. — Of the Right Sections of Arches or Vaults.
PROBLEM I.
To describe the arc of a circle which shall have a given tangent at a given
point, and which shall touch another given arc.
Plate III. Let B k,fig. 4, be one of the given arcs, and lau the other, and let
it be required to describe the arc of a circle, which shall touch the arc B k in
the point k, and the arc lau in some point to be found; let g be the centre of
the arc B k.
Draw g A', and make kp equal to the radius of the circle lau. Draw a straight
line from p to q, the centre of the arc lau, and bisect pq by a perpendicular,
meeting kg in m. Join the points m, q, and prolong mq to /. It is manifest that
mk and ml are equal ; therefore, from m, with the radius mk or ml, describe an
arc kl; and kl will be the arc required.
PROBLEM II.
To describe an oval, representing an ellipse, to any given dimensions of length
and breadth, given in position.
Let A «, B h,fig. 1, be the two given lines bisecting each other in C ; A « being
equal to the length, and B 6 to the breadth.
Find a third proportional to this semi-axis C «, C B,* and make a h equal to the
third proportional ; also find a third proportional to C B, C «, f and make Bg- equal
to the third proportional.
Make the angle B^A equal to about L5^, and let gk meet A a in the point i.
From g, with the radius g B, describe an arc B k, and from h, with the radius h a,
describe an arc I a. Describe the arc kl by the preceding problem to touch the
arc B k in A, and to touch the arc a Z at /, and thus one quarter of the oval will be
completed ; the other three will be found by placing the centres in their proper
positions.
Three or more points a, h, c, might easily have been found in the curve.
Thus, draw A d parallel to B b, and B d parallel to C A. Divide A d into four
equal parts, and divide A C also into four equal parts at 1,2, 3. From b and
through 1, 2, 3, in C A, draw b a, bb, be, and from the points 1, 2, 3, in A d, draw
towards B, to intersect the former in a, b, c, so that we may find the radius of
* Thus, in Jig. 2, draw the two lines G A, A H. making an angle with each other ; make a c equal to a C,
Jig. 1, and A d equal to C H,Jig. 2 ; and make A e equal to A d. Join cd, and draw ef parallel to cd ; then
af is the third proportional.
f That is, in Jig. 2, make A c equal A G or a C, Jig. 1, and A d equal to C B or C i. Jig. 1, and make A G
equal to Ac, and join cd. Draw G H parallel to d c; then A H is the third proportional.
92
PRACTICAL MASONRY.
curvature upon the sides, and at the two ends, by finding the centre of a cir-
cle passing through three points at each extremity, the extremity being the mid-
dle point.
Fig. 3 exhibits the use of this method of describing an oval, in finding the
direction of the joints of arches so as to agree with the normals drawn from the
several divisions of the inner arc. The arcs are marked the same as in fig. 2.
REMARK,
When the height of the arch is equal to or greater than half the span, and
when it is not necessary that the vertical angle should be given, the curves of
the intrados and extrados on the one side may be described from the same cen-
tre, as also those of the other side from another centre.
The most easy Gothic arch to describe is that of which the height of the in-
trados is such as to be the perpendicular of an equilateral triangle, described up-
on the sparing line as a base, and these centres are the points to which the ra-
diating joints must tend.
Gothic arches seldom exceed in height the perpendicular of the equilateral tri-
angle inscribed in the intrados of the aperture ; but when the arch is surmounted
and the height less than the perpendicular of the equilateral triangle made upon
the base, draw a straight line from one extremity of the base to the vertex, and
bisect this line by a perpendicular. From the point where the perpendicular
meets the base of the arch, and with a radius equal to the distance between this
point and the extremity of the base joined to the vertex, describe an arc between
the two points, joined by the straight line, and the curve which forms one side of
the intrados will be complete. In the same manner will be found the curve on
the other side, (see fig. 5,) so that by only two centres the whole of the intrados
will be formed.
The curves of all kinds of Gothic arches whatever may be described by
means of conic parabola, to a given vertical angle, and to any given dimensions.
Thus, in fg. 7, let C e, Cf, be the two tangents, and A c, and B /, the heights of
their extremities. Divide A c and e C each into the same number of equal parts
by the points 1, 2, 3, in each of these lines. Draw^ lines from the corresponding
points 1-1, 2-2, 3-3, &.c. ; and the intersections will form the curve of one side
of the intrados, as we have already seen. The curve on the other side w'ill be
formed in the same manner.
Join B C, and bisect it in g, and join gf, intersecting the curve in /. Draw h k
^parallel to C B, meeting g/ in k. Make / i equal to I k, and i h joined is a tan-
gent at h. Hence, h m perpendicular to h i is the joint.
ON TE E HEDEALS.
93
CHAPTER IV.
SECTION I. — On the Nature and Construction of Trehedrals.
DEFINITIONS.
Every stone bounded by six quadrilateral planes or faces forms a solid, of
which the surfaces terminate on eight points, every three surfaces in one point.
Every three planes thus terminating is termed a solid angle or trehedral.
The angles formed by the intersections of the faces with one another, or the
three plane angles, are called sides of the trehedral, and the angles of inclination
are called, by way of distinction from the other, simply angles.
The three sides, as well as the three angles, are each called a part ; so that
the whole trehedral consists of six parts; and if any three of these parts be given,
the remaining three can be found.
Therefore, in bodies constructed of stone, which are intended to have their
solid angles to consist of three plane angles, the construction of such bodies may
be reduced to the consideration of the trehedral.
As to the remaining surface of the solid which incloses the solid, completely
making a fourth side to the trehedral, it may be of any form whatever, regular or
irregular, or consisting of many surfaces ; it or they have nothing to do in the
construction.
The parts of the trehedral, which may be obtained from three given parts,
are the very same as three parts found in a spherical triangle from three given
parts. This is, in fact, the same as spherical trigonometry.
We shall not, however, enter into any operose analytical investigations, but
treat the subject in the most simple manner, according to the rules of solid
geometry ; and only those trehedrals, which have two of their planes at a right
angle with each other (though there are many cases in which the oblique trehe-
dral would be necessary) ; as the bounds prescribed for this work will not admit
of such an extension of the principles.
If the trehedral have two of its planes perpendicular to each other, it is called
right-angled trehedral ; each of the two faces thus forming a right angle is
called a leg, and the remaining side, joining each leg, is called the hypothenuse.
PROBLEM I.
Given two legs of a right-angled trehedral, to find the hypothenuse.
94
PRACTICAL MASONRY.
Plate II., figs. 1, 2, 3, and 4. Let PON and P O R be the given legs. Draw
P R perpendicular to O P, and PQ perpendicular to ON. From O, as a centre,
with the radius O R, describe an arc intersecting P Q in Q, and join O Q, and
Q O N is the hypothenuse required.
Demonstration. — Suppose the triangle P 0 R revolved upon 0 P, until P R
become perpendicular to the plane of the triangle O P N, then the plane of the
triangle OPR will be perpendicular to the plane of the triangle O P N.
Again, suppose the triangle O N Q to revolve upon O N, and let P Q, or P Q
produced, intersect O N in w, then m Q will always be in a plane passing through
P m and the plane described by m Q will be perpendicular to the plane m O P ;
and as P R is, by supposition, also perpendicular to the plane m O P, therefore
P R and m Q being thus situated in the same plane will meet, except they are
parallel.
Let mQ therefore be revolved until the straight line mQ fall upOn the point R;
let Q then be supposed to coincide with R, then because Q, by supposition,
coincides with R, and the point O is common to the straight lines O Q and O R,
therefore the straight lines O Q and O R having two common points will coincide,
and therefore m O Q will be the hypothenuse required.
PROULEiM II.
Given the hypothenuse and one of the legs, to find the other leg.
Figs. 1, 2, 3, and 4. Let N O Q be the given hypothenuse, and NOP the given
leg, and let these two parts be attached to each other by the straight line O N.
In O N take any point m, and through m draw P Q perpendicular to O N.
Draw PR perpendicular to O P. From the point O, with the radius O Q, de-
scribe an arc Q R and join O R ; then will P O R be the other leg, as required.
These four diagrams show the various positions in which the data may be
placed ; every one will frequently occur in practice.
PROBLEM III.
Given the two legs of a right-angled trehedral, to find one of the angles at the
hypothenuse.
Figs. 5 and 6. Let the two given legs be P O N and P O R. In O P take any
point P, and draw P N perpendicular to O N, and P R perpendicular to P O, and
P K parallel to O N. Make P K equal to P R, and join N K ; then P NK will
be the angle at the hypothenuse.
In fig. 5, the two legs lie upon separate parts ; and in fig. 6, one of the legs
lies upon the other.
Fig. 7 exhibits the same principle applied in finding a series of bevels or
ON TREHEDRALS.
95
angles made by the hypothenuse and a leg. Thus let the two legs be P O N
and POR. From any point m, in OP, draw' wR perpendicular to OP. On
O /«, as a diameter, describe the semicircle O q m, intersecting O N in 5', and join
q m. Make mr equal to mq, and join ?’R; then PrR will be the angle re-
quired.
PROBLEM IV.
Given one of the legs and the inclination of the hypothenuse to that leg, to find
the other leg.
Figs. 8 and 9. Let N O P be the given leg. In O N take any point m, and
draw m i perpendicular to O N. Make i m p equal to the angle which the leg
NOP makes with the hypothenuse. Through any point i, in 7« i, draw P p
parallel to O N, and P Q, perpendicular to O P. IMake P Q equal to ip, and join
O Q, and Q O P will be the other leg.
PROBLE.M V.
Given one of the legs and the angle which the hypothenuse forms with that
leg, to find the hypothenuse.
Figs. 10 and 11. In N O, take any point ???, and draw 7n?i perpendicular
to ON. Make nmp equal to the angle which the hypothenuse makes with the
leg N O P. From the point m as a centre, with any radius mn, describe an arc
n p. Draw p P, n Q parallel to N O, and P Q perpendicular to N O, and join
O Q ; then N O Q is the hypothenuse required.
GENERAL APPLICATIONS OF THE TREIIEDRAL TO TANGENT PLANES.
Example I. — Given the inclination and seat of the axis of an oblique cylinder
or cylindroid, to find the angle which a tangent makes at any point in the circum-
ference of the base with the plane of the base.
Plate III., figs. 6 and 9. Let AEB O be the base of the cylinder or cylin-
droid, C B the seat of the axis, and let B C D be the angle of inclination, and let
O be the point where the tangent plane touches the curved surface of the solid.
Draw O N, a tangent line, at the point O in the base, and draw O P parallel
to C B. IMake the angle P O R equal to BCD, and draw P R perpendicular
to P O.
Then, if the triangle P O R be conceived to be revolved round the line P O as
an axis, until its plane become perpendicular to the plane of the circle A E B C,
the straight line O R will, in this position, coincide with the cylindrical surface,
and a plane touching the cylinder or cylindroid at O will pass through the* lines
O N and O R. Here wall now be given the two legs POR and P O N of a right-
96
PRACTICAL MASONRY.
angled trehedral to find the angle which the hypothenuse makes with the base.
Draw P Q perpendicular to O N, intersecting it in w, and draw^ P S perpendicu-
lar to P Q. Make P S equal to P R, and join m S ; then P m S is the angle re-
quired.
The hypothenuse will be easily constructed at the same time, thus : — make
m Q equal to m S, and join O Q, then N O Q will be the hypothenuse required.
In fig. 1, the method of finding the angle which the tangent plane makes with
the base and the hypothenuse is exhibited at four different points. In the two first
points O from A in the first quadrant, the tangent planes make an acute angle at
each point O ; but in the second quadi’ant, they make an obtuse angle at each
point O.
Fig. 8 is the second position of the construction from the point A, for finding
the angle which the tangent plane makes with the base, and for finding the
hypothenuse enlarged ; in order to show a more convenient method by not only
requiring less space, but less labor. It may be thus described, the two given
legs being P' O' R' and P' O' N'.
Draw P ' m perpendicular to O' N', meeting O N in m. In P' O', make P' v'
equal to V m, and draw the straight line v R', then V v R' will be the inclination
of the tangent plane at the point O.
Again, in O' P' make O'/' equal to O' m\ and draw /'w' parallel to P' R'.
From O', with the radius O' R', describe an arc meeting /' u in m', and draw the
straight line O' u ; then /' O' u is the hypothenuse.
For since P'S' is equal to P' R', and P'f' equal to P' m', and the angles
m'P' S' and v' P' R' are right angles ; therefore the triangle v P' R' is equal to the
triangle m P' S', and the remaining angles of the one equal to the remaining an-
gles of the other, each to each ; hence the angle P' v R' is equal to the angle
P' m' S'.
Again, because O' /' is equal to O' m', and O'Q' is equal to O' R', and O' u is
also equal to O' R' ; therefore O' w' is equal to O'Q', and since the angles O' /' u
and 0'r?i'Q' are each a right angle, therefore the two right-angled triangles have
their hypothenuses equal to each other, and have also one leg in each, equal to
each other ; therefore the remaining side of the one triangle is equal to the re-
maining side of the other, and therefore also the angles which are opposite to the
equal sides are equal ; hence the angle P' O' u is equal to N' O' Q'.
By considering this construction by the transposition of the triangles, the whole
of the angles wdiich the tangent planes make at a series of points O in figs. 6
and 9, and their hypothenuses, may be all found in one diagram, as fig. 4.
Thus, in^g. 10, if the angles A C O, A C O', A C O", A C O'", be respectively
equal to A C O, A C O,' A C O," A C O'", fig. 6, and in fig. 1 0, the semicircle
ON THE PROJECTION OF A STRAIGHT LINE, &c. 97
A O' B be described, and if C D be drawn perpendicular to A B, and the angles
CAD, C B D, be made equal to B C 6 ; then each half of Jig. 10 being
constructed as in jig. 8, the angles at m, m', m", w'", will be respectively equal
to the angle P m S, P ' m S', Q" m" S", Q" m'" S", in Jig. 6.
Also, in Jig. 1 0, the angles CAE, C A g, C A A, C B i, C B A:, C B F, will be
the hypothenuses at the point A, O, O', O", O'", B, in Jig. 6.
We may here observe, 6, that the angles which the tangent planes make
with the plane of the base in the first quadrant are acute ; and those in the sec-
ond quadrant are obtuse, and are the supplements of the angles P m S ; and,
moreover, that all the angles which constitute the hypothenuses of the trehedral
are acute, whether in the first quadrant or second quadrant* of the semicircle
A OB.
SECTION II, — On the Projection of a Straight Line bent upon a Cylindric Surface,
AND THE Method of Drawing a Tangent to such a Projection.
PROBLEM I.
Given the development of the surface of the semi-cylinder, and a straight line
in that development, to find the projection of the straight line on a plane passing
through the axis of the cylinder, supposing the development to encase the semi-
cylindric surface.
Fig. 1 1 . Let A B C be the development of the cylindric surface, B C being
the development of the semi-circumference, and let A C be the straight line
given.
Produce C B to D, making B D equal to the diameter of the cylinder. On B D,
as a diameter, describe the semicircle BED, and divide the semicircular arc
BED into any number of equal parts, at 1,2, 3, &c. ; and its development B C
into the same number of equal parts, at the points./, g, h, &c. Draw the straight
lines fk, gl,hm, See., parallel to B A, meeting A C at the points k, /, m, &c.; also,
parallel to B A, draw the straight lines I 0 , 2 p, 3 g, &c., and draw k 0 , lp,mq, &lc.,
parallel to C D ; and the points 0 , p, q, &,c., are the projections or seats of the
points k, /, m, &c., in the development of the straight line A C.
The projection of a screw is found by this method : — B D may be considered
as the diameter of the cylinder from which the screw is formed ; and the angle
BAG the inclination of the thread with a straight line on the surface ; or B C A
the inclination of the thread with the end of the cylinder. The same principle
also applies to the delineations of the hand-rails of stairs, and in the construction
of bevel bridges.
13
98
PRACTICAL MASONRY.
PROBLEM II.
Given the entire projection of a helix or screw, in the surface of a semi-cylinder,
and the projection of a circle in that surface perpendicular to the axis, upon the
plane passing through the axis to draw a tangent to the curve at a given point.
Fig. 12. Let B P K be the projection of the helix or screw, and B A the
projection of the circumference of a circle, and since this circle is in a plane per-
pendicular to the plane of projection, it will be projected into a straight line A B,
equal to the diameter of the cylinder.
On A B as a diameter, describe the semicircle A r B, and draw P r perpendic-
ular to and intersecting AB in 9, join the points e, r, and produce er to /.
Produce A B to C, so that B C may be equal to the semicircular arc B r A.
Draw C D perpendicular to B C, and make C D equal to A K, and draw the
straight line B D ; then B D will be the development of the curve line B P K.
Draw P u parallel to A C, meeting B D in ii, and draw ii t perpendicular to
B C. Draw r g perpendicular to er, and make rg equal to B t. Draw^n per-
pendicular to A C, meeting B C in n, and draw the straight line n P ; then nP
will touch the curve at the point P.
Or the tangent may be drawn independent of B C D thus: — Draw P r per-
pendicular to AB, and rg a tangent at r. Make equal to ihe development of
r B, and draw g n perpendicular to B C, meeting B C in n, and join n P, which is
the tangent required.
SECTION III. — Application of Geometry to Planes and Elevations, and also to the
Construction of Arches and Vaults.
PRELIMINARY PRINCIPLES OF PROJECTION.
If from a point A', Plate \\.,fig. 1, in space, a perpendicular K'a be let fall to
any plane P Q whatever, the foot a of this perpendicular is called the projection
of the point A' upon the plane P Q.
If through different points A', B', C', D', jigs. 2, 3, 4, of any line
A' B' C' D' whatever in space, perpendiculars A'a, B'6, C'c, D'd, be
let fall upon any plane P Q whatever, and if through a, h, c, d, the pro-
jection of the points A', B', C', D', in the plane P Q, a line be drawn,
the line thus drawn will be the projection of the line A' B' C' D' given
in space.
If the line A'B' C' D' fig. 3, be straight, the projection abed will
also be a straight line ; and if the line B' C' D' Jig. 2, be a curve not in
a plane perpendicular to the plane P Q, the curve abed which is the pro-
. utr/i/rt s f'f
WW.WiLson Sr
APPLICATION OF GEOMETRY TO PLANES, &c.
99
jection of the curve A' B' C' D' in space, will be of the same species with
the original curve, of which it is the projection. Hence, in this case, if the
original curve A'B'C'D' . . . . be an ellipse, a parabola, a hyperbola, &c., the
projection abed ... . will be an ellipse, a parabola, a hyperbola, &c. The cir-
cle and the ellipse being of the same species, the projected curve may be a
circle or ellipse, whether the original be a circle or ellipse, as in fig. 4.
The plane in which the projection of any point, line, or plane figure is situa-
ted, is called the plane of projection, and the point or line to be projected is
called the primitive.
The projection of a curve will be a straight line when the curve to be project-
ed is in a plane perpendicular to the plane of projection. Hence the projection of
a plane curve is a straight line.
If a curve be situated in a plane which is parallel to the plane of projection, the
projection of the curve will be another curve equal and similar to the curve of
which it is the projection.
The projection upon a plane of any curve of double curvature whatever is al-
ways a curve line.
In order to fix the position and form of any line whatever in space, the position
of the line is given to each of two planes which are perpendicular to each other;
the one is called the horizontal plane and the other the vertical plane ; the pro-
jection of the line in question is made on each of these two planes, and the two
projections are called the two projections of the line to be projected.
Thus we see, in fig. 5, where the parallelogram U V W X represents the hori-
zontal plane, and the parallelogram U V Y Z represents the vertical plane, the
projection a 6 of the line A'B' in space upon the horizontal plane U V W X is
called the horizontal projection, and the projection A B of the same line upon the
vertical plane U V Y Z is called the vertical projection.
The two planes upon which we project any line whatever are called the
planes of projection.
The intersection U V of the two planes of projection is called the ground-
line.
When we have two projections ab, A B, of any line A' B' in space, the line
A'B' will be determined by erecting to the planes of projection the perpendiculars
a A', B i'. . . ., A A', B B'. . . . through the projections a,b, ....; A, B, . . . .
of the original points A', B', .... of the line in question. For the perpendiculars
a A', A A, erected from the projections a, A, of the same point A', will intersect
each other in space in a point A', which will be one of these in the line in
question. It is clear that the other points must be found in the same manner as
this which has now been done.
100
PRACTICAL MASONRY.
When we have obtained the two projections of a line in space, whether imme-
diately from the line itself, or by any other means whatever, we must abandon
this line in order to consider its two projections only. Since, when we design a
working drawing, we operate only upon the two projections of this line that we
have brought together upon one plane, and we no longer see any thing in space.
However, to conceive that w^hich we design, it is absolutely necessary to carry
by thought the operations into space from their projections. This is the most
difficult part that a beginner has to surmount, particularly when he has to consid-
er at the same time a great number of lines in various positions in space.
The perpendicular A' a, fig. 5, let fall from any point A whatever in space up-
on the plane X V of projection, is called the projectant of the point A' upon this
plane. Moreover, the perpendicular distance between the point A' and the hori-
zontal plane X V is called the projectant upon the horizontal plane, or simply the
horizontal projectant; and the peipendicular distance A' A between the original
point A' and the vertical plane U Y is called the projectant upon the vertical
plane, or simply the vertical projection.
We shall remark, so as to prevent any mistake, that the horizontal projectant
A'a is the peipendicular let fall from the original point upon the horizontal plane,
and that the vertical projectant is the perpendicular let fall from that point upon
the vertical plane. Hence the horizontal projectant is parallel to the vertical
plane, and is equal to the distance between the original point and the horizontal
plane ; and the vertical projectant is parallel to the horizontal plane, and is equal
to the distance between the original point and the vertical plane.
We may remark, that if through a, fig. 6, the horizontal projection of the point
A', we draw a perpendicular o a to U V, the ground-line, this perpendicular a a
will be equal to the measure of the vertical projectant A' A; consequently the
distance of the point A' to the vertical plane is equal to the distance betw'een a,
its horizontal projection, and U V, the ground-line, measured in a perpendicular to
U V. In like manner, if through A, the vertical projection of the point A', w'e
draw a perpendicular A a to U V, the ground-line, this perpendicular A a will be
equal to the measure of the horizontal projectant A a ; consequently, the distance
of this point A' to the horizontal plane is equal to the distance between A, its
vertical projection, and U V, the ground-line, measured in a perpendicular to U V.
To these very important remarks w e shall add one which is not less so. Two
perpendiculars, a a, fig. 6, A a, being let fall from the projections a, A, to the
same point A', upon the ground-line U V, will meet each other in the same point
a of the said ground -line U V.
If we now wished the two projections of a point A', fig. 6, or of any line
A' B' whatever, to be upon one or the same plane, it is sufficient to imagine the
APPLICATION OF GEOMETRY TO PLANES, &c.
101
vertical plane U V Y Z to turn round the ground-line U V, in such a manner as
to be the prolongation of the horizontal plane U Y W X ; for it is clear that this
plane will carry with it the vertical projection A or A B of the point, or of the
line in question. Moreover, we see, and it is very important, that the lines A a,
B b, perpendicular to the ground-line U Y will not cease to be so in the motion
of the plane U Y YZ; and, as the corresponding lines a a, bh, are also perpen-
diculars to the ground-line U Y, it follows that the lines a a', hb\ will be the re-
spective prolongation of the lines a a, 6 b.
Hence it results, when we consider objects upon a single plane, that the projec-
tions a, A, of the point A' in space are necessarily upon the same perpendicular
A a to the ground -line U Y.
It is necessary to call to mind, that the distance A a measures the distance from
the point in space to the horizontal plane (the point A being the vertical projec-
tion of this point), and that the line a a measures the distance from the same
point in space to the vertical plane.
It follows, that if the point in space be upon the horizontal plane, its distance
with regard to this last named plane will be zero or nothing, and the vertical A a
will be zero also. Moreover, the vertical projection of this point will be upon the
ground-line at the foot a of the perpendicular a a let fall upon the ground-line
from the horizontal projection a of this point.
Again, if the point in space be upon the vertical plane, its distance, in respect
of this plane, will be zero, the horizontal a a will be zero, and the horizontal
projection of the point in question will be the foot a of the perpendicular A a let
fall upon the ground-line from the vertical projection A of this point.
In general, we suppose that the vertical projection of a point is above the
ground-line, and that the horizontal projection is below ; but from what has been
said, it is evident that if the point in space be situated below the horizontal line,
its vertical projection will be below the ground-line ; for the distance from this
point to the horizontal plane cannot be taken from the base line to the top, but
from the top to the base with respect to its plane.
So, if the point in space be situated behind the vertical plane, its horizontal
projection will be above the ground-line, from which we conclude, —
1st. If the point in question be situated above the horizontal plane, and be-
fore the vertical plane, its vertical projection will be above, and its horizontal pro-
jection below, the ground -line.
2d. If the point be situated before the vertical plane, and below the horizontal
plane, the two projections will be below the ground-line.
3d. If the point be situated above the horizontal plane, but behind the vertical
plane, the two projections will be above the ground-line.
102
PRACTICAL MASONRY.
4th. Lastly. If the point be situated above the horizontal plane, and behind
the vertical plane, the vertical projection will be below, and the horizontal pro-
jection above, the ground-line.
The reciprocals of these propositions are also true.
If a line be parallel to one of the planes of projection, its projection upon the
other plane will be parallel to the ground-line. Thus, for example, if a line be
parallel to a horizontal plane, its vertical projection will be parallel to the ground-
line ; and if it is parallel to the vertical plane, its horizontal projection will be par-
allel to the ground-line.
Reciprocally, if one of the projections of a line be parallel to the ground-line,
this line will be parallel to the plane of the other projection. Thus, for example,
if the vertical projection of a line be parallel to the ground-line, this line will be
parallel to the horizontal plane, and vice versa.
If a line be at any time parallel to the two planes of projection, the two pro-
jections of this line will be parallel to the ground -line; and reciprocally, if the
two projections of a line be parallel to the ground-line, the line itself will be at
the same time parallel to the two planes of projection.
If a line be perpendicular to one of the planes of projection, its projection
upon this plane will only be a point, and its projection upon the other plane will
be perpendicular to the ground-line. Thus, for example, if the line in question
be perpendicular to the horizontal plane, its horizontal projection will be only a
point, and its vertical projection will be perpendicular to the ground-line.
Reciprocally, if one of the projections of a straight line be a point, and the
projection of the other perpendicular to the ground-line, this line will be perpen-
dicular to the plane of projection upon which its projection is a point. Thus
the line will be perpendicular to the horizontal plane, if its projection be the
given point in the horizontal plane.
If a line be perpendicular to the ground-line, the two projections will also
be perpendicular to this line. The reciprocal is not true ; that is to say, that
the two projections of a line may be perpendicular to the ground-line, without
having the same line perpendicular to the ground-line.
If a line be situated in one of the planes of projection, its projection upon
the other will be upon the ground-line. Thus, if a line be situated upon a
horizontal plane, its vertical projection will be upon the ground-line ; and if
this line were given upon the vertical plane, its horizontal projection would be
upon the ground-line.
Reciprocally, if one of the projections of a line be upon the ground-line, this
line will be upon the plane of the other projection. Thus, for example, if it
be the vertical projection of the line in question which is upon the ground, this
:V.PPL IC ATIO N OF GEOMETRA^ TO PLANES, &c. 103
line will be upon the horizontal plane ; if, on the contrary, it were upon the
horizontal projection of this line which was upon the ground-line, this line
would be upon the vertical plane.
If a line be at any time upon the two planes of projection, the two pro-
jections of this line would be upon the ground-line, and the line in question
would coincide with this ground-line. Reciprocally, if the two projections of a
line were upon the ground-line, the line itself would be upon the ground-line.
If two lines in space are parallel, their projections upon each plane of pro-
jection are also parallel. Reciprocally, if the projections of two lines are par-
allel on each plane of projection, the two lines will be parallel to one another in
space.
If any two lines whatever in space cut each other, the projections of their point
of intersection will be upon the same perpendicular line to the ground-line, and
upon the points of intersection of the projections of these lines. Reciprocally, if
the projections of any two lines whatever cut each other in the two planes of pro-
jection, in such a manner that their points of intersection are upon the same per-
pendicular to the ground-line, these two lines in question will cut each other in
space.
The position of a plane is determined in space, when we know the intersec-
tions of this plane with the planes of projection. ' ^
The intersections A B, AC, of the plane in question, with the planes of pro-
jection, are called the traces of this plane.
The trace situated in the horizontal plane is called the horizontal trace, and
the trace situated in the vertical plane is called the vertical trace.
A very important remark is, that the two traces of a plane intersect each other
upon the ground-line.
If a plane be parallel to one of the planes of projection, this plane will have only
one trace, which will be parallel to the ground-line, and situated in the other
plane of projection. Reciprocally, if a plane has a trace parallel to the ground-
line, this plane will be parallel to the plane of projection which does not contain
this trace. Thus : —
1st. If a plane be parallel to the horizontal plane, this plane will not have a
horizontal trace, and its vertical trace will be parallel to the ground-line. Like-
wise, if a plane be parallel to the vertical plane, this plane will not have a verti-
cal trace, and its horizontal trace will be parallel to the ground-line.
2d. If a plane has only one trace, and this trace parallel to the ground -line,
let it be in the vertical plane ; then the plane will be parallel to the horizontal
plane. So if the trace of the plane be in the horizontal plane, and parallel to the
ground-line, the plane will be parallel to the vertical plane.
104
PRACTICAL MASONRY.
If one of the traces of a plane be perpendicular to the ground-line, and the oth-
er trace in any position whatever, this plane will be perpendicular to the plane of
projection in which the second trace is. Thus, if it be a horizontal trace which is
perpendicular to the ground -line, the plane will be perpendicular to the vertical
plane of projection ; and if, on the contrary, the vertical trace be that which is
perpendicular to the ground-line, then the plane will be perpendicular to the hor-
izontal plane.
Reciprocally, if a plane be perpendicular to one of the planes of projection
without being parallel to the other, its trace upon the plane of projection to which
it is perpendicular will be to any position whatever, and the other trace will be
perpendicular to the ground-line. Thus, for example, if the plane be perpendic-
ular to the vertical plane, the vertical trace will be in any position whatever, and
its horizontal trace will be perpendicular to the ground-line. The reverse will
also be true, if the plane be perpendicular to the horizontal plane.
If a plane be perpendicular to the two planes of projection, its two traces will
be perpendicular to the ground-line. Reciprocally, if the two traces of a plane
are in the same straight line perpendicular to the ground-line, this plane will be
perpendicular to both the planes of projection.
If the two traces of a plane are parallel to the ground-line, this plane will be
also parallel to the ground-line. Reciprocally, if a plane be parallel to the
ground-line, its two traces will be parallel to the ground-line.
When a plane is not parallel to either of the planes of projection, and one of its
traces is parallel to the ground-line, the other trace is also necessarily parallel to
the ground-line.
If two planes are parallel, their traces in each of the planes of projection will
also be parallel. Reciprocally, if on each plane of projection the traces of the two
planes are parallel, the planes will also be parallel.
If a line be perpendicular to a plane, the projections of this line will be in each
plane of projection perpendicular to the respective traces in this plane. Recip-
rocally, if the projections of a line are respectively perpendicular to the traces of
a plane, the line will be perpendicular to the plane.
If a line be situated in a given plane by its traces, this line can only intersect
the planes of projection upon the traces of the plane which contains it. More-
over, the line in question can only meet the plane of projection in its own projec-
tion. Whence it follows, that the points of meeting of the right line and the
planes of projection are respectively upon the intersections of this right line and
the traces of the plane which contains it.
If a right line, situated in a given plane by its traces, is parallel to the horizon-
tal plane, its horizontal projection will be parallel to the horizontal trace of the
DEVELOPMENTS OF THE SURFACES OF SOLIDS. 105
given plane, and its vertical projection will be parallel to the ground -line. Like-
wise, if the right line situated in a given plane by its traces is parallel to the
vertical plane, its vertical projection will be parallel to the vertical line of the plane
which contains it, and its horizontal projection will be parallel to the ground-line.
Reciprocally, if a line be situated in a given plane by its traces, and, for
example, let its horizontal projection be parallel to the horizontal trace of the
given plane, this line will be parallel to the horizontal plane, and its vertical
projection will be parallel to the ground-line. Likewise, if the vertical pro-
jection of the line in question be parallel to the vertical trace of the given plane,
this line will be parallel to the vertical plane, and its horizontal projection will be
parallel to the ground-line.
SECTION IV. — Ox THE Developments of the Surfaces of Solids.
PROBLEM I.
To find the development of the surface of a right semi-cylinder.
Plate \Y.,fig. 7. Let ACDE be the plane passing through the axis. On
A C, as a diameter, describe the semicircular arc ABC. Produce C A to F,
and make A F equal to the development of the arc ABC. Draw F G parallel
to A E, and E G parallel to A F ; then AF GE is the development required.
PROBLE.M II.
To find the development of that part of a semi-cylinder contained between
two perpendicular surfaces.
Figs. 8, 9, and 10. Let A C D E be a portion of a plane passing through the
axis of the cylinder, C D and A E being sections of the surface, and let D E and
G F be the insisting lines of the perpendicular surface ; also let A C be perpen-
dicular to A E and C D. On A C, as a diameter, describe the semicircular arc
ABC. Produce C A to H, and make A H equal to the development of the
arc ABC. Divide the arc ABC, and its development, each into the same
number of equal parts at the points 1, 2, 3.
Through the points 1, 2, 3, &c., in the semicircular arc and in its develop-
ment, draw straight lines parallel to AE, and let the parallel lines through 1, 2,
3, in the arc ABC, meet F G in p, q, r, &.C., and AC in A:, /, m, &c. Trans-
fer the distances kp, Iq, mr, &lc., to the development upon the lines 1 a, 2
3 c, &.C. Through the points F, a, b, c, &c., draw the curve line F c I. In the
same manner draw the curve line E K ; then F E K I will be the development
required.
14
106
PRACTICAL MASONRY.
PROBLEM III.
To find the development of the half surface of a right cone, terminated by a
plane passing through the axis.
Fig. 1 1 . Let ACE be the section of the cone passing along the axis
A E ; and C E the straight lines which terminate the conic surface, or the two
lines which are common to the section CAE and the conic surface ; and let
A C be the line of common section of the axal plane, and the base of the cone. *
On A C, as a diameter, describe a semicircle ABC. From E, with the
radius E A, describe the arc A F, and make the arc A F equal to the semi-
circular arc ABC, and join E F ; then the sector A E F is the development
of the portion of the conic surface required.
•
PROBLEM IV.
To find the development of that portion of a conic surface contained by a
plane passing along the axis, and two surfaces perpendicular to that plane.
Fig. 12. Let ACE be the section of the cone along the axis, and let AC
and GI be the insisting lines of the perpendicular surfaces. Find the develop-
ment A E F as in the preceding problem. Divide the semicircular arc ABC,
and the sectorial arc A F, each into the same number of equal parts, at the
points 1, 2, 3, &.C. From the points 1, 2, 3, &.C., in the semicircular arc, draw
straight lines 1 k, 2 /, 3 m, &.C., perpendicular to A C. From the points k, /, m,
&.C., draw straight lines A'E, /E, mE, &.C., intersecting the curve A C in q, r,
&c. Draw the straight lines p t, qu, r v, &.C., parallel to one side, E C meeting
A C in the points t, ii, v, &lc. Also from the points 1, 2, 3, in the sectorial arc
A F, draw the straight lines 1 E, 2 E, 3 E, &,c. Transfer the distances pt, qu,
rv, &.C., to 1 a, 2 b, 3 c, &lc. ; then through the points A, a, h, c, &lc., draw the
curve A c F, and A c F is one of the edges of the development, and by draw-
ing the other edge, the entire development A G H F will be found.
SECTION V. — Construction of the Moulds for Horizontal Cylindretic Vaults, either
TERMINATING RiGHTLY OR OBLIQUELY, UPON PlANE OR CYLINDRICAL V'ALLS, TVITH THE
Joints of the Courses either in the Direction of the Vault, perpendicular to the
Faces, or in Spiral Courses.
DEFINITIONS OF MASONRY, WALLS, VAULTS, &c.
Stone-cutting is the art of reducing stones to such forms that when united
ogether they shall form a determinate whole.
ON WALLS AND VAULTS.
107
In preparing stones for walls, of which their surfaces are intended to be per-
pendicular to the horizon, nothing more is necessary than to reduce the stone to
its dimensions, so that each of its eight solid angles may be contained by three
plane right angles.
Moreover, in working the stones of common straight right cylindretic vaults,
where the planes of the sides of the joints terminate upon the intrados or ex-
trados of the arch or vault, in straight parallel ruled lines of the cylindretic
surface, there can be no difficulty ; for if one of the beds of the stone be
formed to a plane surface, and if this side be figured to the mould, and the
opposite ends squared, and, lastly, the face or vertical moulds applied upon the
ends thus squared, and their figures drawn, these figures will be the two ends
of a prism, consisting of equal and similar figures, and will be similarly situated ;
and therefore we have only to form this prism, in order to form the arch-stone
required.
But the formation of the stones in the angles of vaults, and in the courses
of spherical niches and domes, are much more difficult, and require more
consideration. In such constructions various methods may be employed, and
some of these, in particular instances, with great advantage, both in the saving
of workmanship and material, as we shall have occasion to show. In general,
however, previous to the reducing of a stone to its ultimate form for such a
situation, it will be found convenient to reduce the stone to such a figure as w'ill
include the more complex figure of the stone required, so that any surface of
the preparatory figure may either include a surface or arris of the stone re-
quired to be formed, or be a tangent to this surface.
Surfaces are brought to form by means of straight and curved edges, always
applied in a plane perpendicular to the arris-lines, so that, when a surface is
thoroughly formed, the edge of application may have all its points in contact
with the surface in its whole intended breadth.
A wall, in masonry, is a mass of stones or other material, either joined to-
gether with or without cement, so as to have its surfaces such that a plumb-
line, descending from any point in either face, will not fall without the solid.
One of the faces of a wall is generally regulated by the other, and the reg-
ulating surface is called the principal face.
The line of intersection of the principal face of a wall and a horizontal plane
on a level with the ground, or as nearly so as circumstances will permit, is called
the base-line.
A horizontal section of a wall, through the base-line, is called the seat of the
wall.
The other side of the seat of a wall, opposite to the base-line, is called the
rear-line.
108
PRACTICAL MASONRY.
In exterior walls the outer surface is always the principal face, and the base
and rear-lines are generally so situated, that normals drawn to the base-line,
between the base and rear-lines, are all equal to one another. This uniform-
ity most frequently takes place also in partition or division walls ; but, in some
instances, on account of a room being circular or elliptical, while the other faces
are plane or curved surfaces, this equality of the normals cannot subsist.
If a wall be cut by a plane perpendicular to the base-line, or if the base-line
be a curve perpendicular to a tangent through the point of contact, such a sec-
tion is called a right section.
Hence, according to this definition, since the base-line is always in a horizon-
tal plane, every straight line and every tangent to a base-line, when it is a curve,
will be a horizontal line, therefore the right section must be in a vertical plane.
Walls are denominated according to the figure of their base-line. When the
base-line is straight, the wall is said to be straight. Hence, if the figure of the
base be an arc or the whole circumference of a circle, or a portion or the entire
curve of an ellipse, the wall is said to be circular or elliptical. Other forms sel-
dom occur in building.
Walls are more strictly defined by the joint consideration of the figures of
their bases and right section.
When the base and the right section of a wall are each a straight line, and
all the horizontal sections straight lines, the face of the wall is called a ruler
surface, and if all the right sections have the same inclination, the wall is called
a straight inclined wall ; if they are all vertical, the wall is called an erect straight
wall, or a vertical straight wall. If the right sections vary their inclination, the
wall is called a winding wall.
When the base-line is the circumference or any arc of a circle, and the right
section a straight line perpendicular to the horizon, the wall is said to be cylin-
dric. If the right sections of a wall be all equally inclined to the horizon, the
wall is said to be conic ; and thus a wall takes also the name by which its sur-
face is called ; hence a straight wall, which has its right sections either vertical
or at the same inclination, is called a plane wall.
A wall in tallus, or a battering icall, is that of which the vertical section of the
principal face is a straight line not perpendicular to the horizon. This vertical
section is called the tallus-line.
The horizontal distance between the foot of the tallus-line and the plumb-
line, passing through its upper extremity, is called the quantity of hatter ; and
the plumb-line, from the top of the tallus-line to the level of its foot, is called
the vertical of the baiter.
The interstices between the stones, for the insertion of cement or mortar, in
* A' ^
/r fK M/f 0/1 Sc.
PI
o.
ON OBLIQUE ARCHES.
109
order to connect the stones into one solid mass, are called joints, and the sur-
faces of the stones between which the mortar is inserted are called the sides of
the joints.
When the sides of the joints are everywhere perpendicular to the face of a
wall, and terminate in horizontal planes upon that face, such joints are called
coursing-joints ; and the row of stones between every two coursing-joints is
called a course of stones.
An arch or vault, in masonry, is a mass of stones suspended over a hollow,
and supported by one or more walls at its extremities, the surface opposed to
the hollow being concave, and such that a vertical line, descending from any
point in the curved surface, may not meet the curved surface in another point.
The concave surface under the arch or vault is called the intrados of that arch
or vault ; and if the upper surface be convex, this convex surface is called the
extrados.
Those joints which terminate upon the intrados in horizontal lines are called
coursing-joints, and the coursing-joints will either be straight, circular, or elliptic,
according as the horizontal sections of the intrados are straight, circular, or
elliptic.
Whether in walling or in vaulting, the joints of the stones should always be
perpendicular to the face of the wall, or to the intrados of the arch, and the joints
between the stones should either be in planes perpendicular to the horizon, or in
surfaces which terminate upon the face of the wall or intrados of a vault in hori-
zontal planes ; these positions being necessary to the strength, solidity, and
durability of the work.
Walls and vaults being of various forms, namely, straight, circular, and elliptic,
depending on the plan of the work ; hence the construction will depend upon
the simple figure or upon the complex figure when combined in two.
SECTION VI. — On Oblique Arches.
PROBLEM I.
To execute an oblique cylindroidic arch, intersecting each side of the wall in a
semicircle, the imposts of the arch being given.
Let fig. 2, Plate V., be the elevation, and in fig. 5, let A B C D, E F G H, be
the two imposts which are equal and similar parallelograms, having the sides A B,
FE, one of each in a straight line, and the sides D C and GH in a straight line.
Join G C, and on G C, as a diameter, describe the semicircle G I C, which, if
110
PRACTICAL MASONRY.
conceived to be turned upon the line G C as an axis, until its plane become
perpendicular to the seat B C GF of the soffit of the arch, it will be placed in its
due position. Divide the semicircular arc GIG into as many equal parts as the
ring -stones are to be in number. We shall here suppose there are to be nine
ring-stones. From the points of division 1, 2, 3, &,c., draw ordinates perpendic-
ular to G C, meeting G C in the points p, q, r, &c. Perpendicular to C B, the
jamb-line of the impost, draw the lines pi, q2, r 3, &,c. ; from the point C as a
centre, with the chord of one ninth part of the semicircular arc, C I G', describe an
arc intersecting /) 1 C B at 1 ; from the point 1, with the same radius, describe an
arc intersecting the line 9 2 in the point 2 ; from the point 2, as a centre, with the
same radius, describe an arc intersecting the line r 3 in the point 3 ; and so on.
Join the point C and 1 ; 1 and 2 ; 2 and 3, &c., and thus form the entire edge
C K L of the development of the semicircular arc GIG.
Through the points 1, 2, 3, &c., in G K L, draw the lines I j3, 2 y, 3 d, &lc.,
parallel to C B, and make \ (3, 2 y, 3 8, &.C., each equal to C B ; and join B (3, /3 y,
y 8, &,c. ; then G B /3 1 is the soffit of the first ring-stone ; 1 /3 2 is the soffit of
the second ring-stone ; 2^53, the soffit of the third ring-.stone ; and so on.
Perpendicular to G F draw F J ; produce C B to J ; and, parallel to C J, draw
p s, q t, rii, &LC. Intersecting F J in the points v, w, x, &.C., make v s, w t, x u,
&c., respectively equal to /j 1,
'■SSi
1
I
«'
' >
/
r
ON OBLIQUE AKCHES.
125
sary to remind the reader, that the convex edge of the squares at D and G
is to be applied upon the hollow soffit already wrought. The curvature of
these moulds may be shown by calculation thus : let R be the radius of
curvature, a = the semi-transverse axis, and h = the semi-conjugate ; then
6 : rt : : a : R =
6
As, for example to this formula, let the radius of the cylindric intrados, or b =
13 feet, and the semi-transverse axis, or a = 28 feet.
28
28
224
56
13)784(60 feet 4 inches nearly
78
4
12
To find the angle of the joints of the face of the arch, and intrados of the
oblique arch with spiral joints.
Let the semicircular arc ABC, Fig. 4, be a section of the intrados at right
angles to the axis of the cylinder. Draw C D and A E perpendicular to the
diameter A C. Draw A D, making an angle with C D, equal to the inclination
which the plane of the face of the arch makes with the vertical plane which is
parallel to the axis of the cylinder, and which passes through the springing-line
of the arch.
Find the edge D/G of the development and face of the arch, or draw the
curve D/G with a mould made from the development before shown. Draw
the face of the ring-stones AKD. Let it now be required to find the fourth
from the point D. IMake D / equal to the portion D 4 of the intrados AKD.
Draw//, the development of a part of the longitudinal spiral joint corresponding
to the point 4 of the elliptic arc AKD. Draw the line « / a tangent to the curve at
/. To do this, we shall again repeat the process of which the principle has already
been taught, namely: — On C D, as a diameter, describe the semicircle C^D
and draw / q, intersecting C D perpendicularly. Draw a tangent to the semi-
circular arc at the point q, and make qu equal to the development of the portion
D of the semicircular arc. Draw u t perpendicular to C D, meeting C D, or
C D produced in the point /. Through / draw the straight line /f, and t s will be
a tangent to the curve at the point. By this means we have the angles which
the spiral joints in the intrados make at the point 4 with the elliptic curve
AKD.
To find the angle made by the normal and the curve, in fig. 4.
126
PRACTICAL MASONRY.
In fig. 7, draw the straight line ab, and make ab equal to the radius of curva-
ture of the elliptic arc A K D at the point 4. This radius would be near enough
to make it the half of the half sum of the semi-parameters of the two axes.
But if greater nicety is required, let the radius of curvature be denoted by ii,
the semi-transverse axis O D or O A be denoted by a, and the semi-conjugate,
which is the radius of the semi-circular arc ABC, be denoted by b, and Jet the
distance Op be denoted by x ; then will r— ; which will be exact
to the number of figures found in the operation here indicated.
Having thus found the radius of curvature, either mechanically or by calcula-
tion, make ab, fig. 7, equal to that radius. From the point a as a centre, with
the distance a b, describe the arc be ; and draw the straight line b d a. tangent to
the curve.
To find the angle made by a tangent plane to the cylindric surface at the
point 4, fig. 4, and the plane of the face of the arch.
Draw the straight line 4ua tangent to the elliptic curve A K D at the point 4,
and draw 4 v parallel to AD. Transfer the angle u 4v io a be, fig. 5.
In fig. 5, at the point b, in the straight line b e, make the angle eb d equal to
the angle D O P, fig. 3, which the axis makes with the plane of the face of the
arch. Again, in fig. 5, draw ef perpendicular to a b, intersecting a i in the point
a. Draw e d perpendicular to e b, and e e perpendicular to e f. IMake e e equal
to e d, and join e a; then will the angle e af be the inclination of the curved
surface of the cylindric intrados and the face of the ring-stones.
We have now ascertained two sides, and the contained angle of the trehedral ;
in order to find the remaining parts, the third side of this trehedral is the angle of
the joints of the intrados and face of the arch, by applying the proper curved
moulds to the angular point ; it is, however, rather unfavorable to our purpose,
that the angle a b d. Jig. 7, is a right angle, and that the angles I ft and Ifs, fig.
4, differ but in a very small degree from right angles. As from this circum-
stance the principle cannot be made evident, we shall therefore suppose, that
these angles have at least a certain degree of obliquity.
In Jigs. 3 and 5, let A B C equal to angle I fit, fig. 4, and A B D, Jigs. 3 and 6,
equal to the angle abd,fig. 7 ; thus, in figs. 3 and 6, draw D e, intersecting A B
in /, or producing D c to meet A B in /. At the point /in the straight line
1
i
I
i
N
V
9
T
A R r 1^1 K
A CIECULAR ARCH IN A CIRCULAR WALL.
127
When each of the given sides is a right angle, then the remaining side of the
trehedral will be the same as the contained angle ; that is, the angle of the joints
of the intrados and face of the arch will be the same as the angle e af Jig. 5.
In this case, no lines are necessary in order to discover the angle of the joints.
In order to apply the angle C B K, one of the lines which applies to the face
must be straight, and the curved edge shown by the bevel at D of the preceding
plate must be so applied, that the other leg of the bevel may be a tangent to the
curve at the angular point B, and this will complete what is necessary in the
construction of an oblique arch with spiral joints.
SECTION VII. — A Circular Arch in a Circular Wall.
PROBLEM I.
To execute a semi-cylindric arch in a cylindric wall, supposing the axes of the
two cylinders to intersect each other. Given the two diameters of the wall, and
the diameter of the cylindric arch, and the number of arch-stones.
Fig. 1, Plate IX. From any point b, w ith the radius of the inner circle of the
wall, describe the circle A B C, or as much of it as may be necessary ; and from
the same point o, wdth the radius of the exterior face of the w'all, describe the cir-
cle D E F, or as much of it as may be found convenient.
Apply the chord AB equal to the width of the arch, and draw DA and E B
perpendicular to AB or DE; then ABDE will be the plan of the cylindric
arch.
Draw Op perpendicular to A B, and draw t v perpendicular to Op. From
the point p as a centre, with the radius of the intrados of the arch, describe the
semicircular arc q7's; and from the same point p, with the radius of the extra-
dos, describe the semicircular arc t u v. Divide the arc qrs into as many equal
parts as the arch-stones are intended to be in number, that is, here into nine equal
parts. From the centre p, draw lines through the points of division to meet the
curve tuv; and these lines will be the elevation of the joints ; and the joints,
together with the intradosal and extradosal arcs, will complete the elevation of
the arch.
Find the development. Jig. 2, as in Jig. 9, Plate IV., and the parallel equi-
distant lines to the same number as the joints in the elevation will be the joints of
the .soffits of the stones; and the surfaces comprehended by the parallel lines
and the edges of the developments will be the moulds for shaping the soffits of
the stones.
128
PRACTICAL MASONRY.
In jig. 3. Let A B be equal to the diameter of the external c}dinder. Draw
A C and B D each perpendicular to A B. Bisect A B in p, from which describe
the intradosal and extradosal arcs, and draw the joints as in jig. 1. Produce the
joints to meet A C or B D, in the points e,f, g, Slc. ; then it is evident that, since
every section of a cylinder is an ellipse, the lines p A, p e, pf, p g, &c., are the
semi-transverse axes of the curves which form the joints in the face of the arch,
and that these curves have a common semi-conjugate axis equal to half the
diameter of the cylinder.
Therefore, upon any indefinite straight line p Q, jig. 4, set off the semi-axis
p A, p e, p f p g, &.C., and draw p B perpendicular to p Q. From p, with the
radius p A, describe an arc A B. On the semi-axes p e and p B, describe the
quadrantal curve of an ellipse ; in the same manner describe the quadrantal
curves /B, gB, &,c. Make p q equal to p q,jig. 3, and in jig. 4 draw q t paral-
lel to p B, intersect the curves A B, e B, /B, &lc., in the points i, k, I, &,c. ; then
h i m, h k n, h I o, &.C., are the bevels to be applied in forming the angles of the
joints ; namely, the bevel h i m is that of the impost, the straight side h i being
applied upon the soffit or intrados, and the curved part i m horizontally to the
curve of the exterior side of the wall ; the point /i, of the bevel h k n, jig. 4, applies
to the point k, jig. 3, so that k h may coincide with the joint upon the intrados,
and the curved edge kn,fig. 4, upon the face k n,fig. 3 ; and so on.
As to the angles which the beds of the stones make with the intrados, they are
all equal, and may be found from the elevation s v y x,fig. 1 ; w'hich is the same
as a section of one of the arch-stones perpendicular to any one of the joints
on the soffits.
The faces of the stones must be wrought by a straight edge, by perpendicular
lines. 'Phe first thing to be done is to work one of the beds ; secondly, work the
intrados, — at first as a plane surface at an angle s x y, or x s v,jig. 1 ; then gauge
off the bed of the soffit, and work the other bed of the stone by the angle v s x or
y X s ; then apply the proper soffit, 1 , 2, or 3, jig. 2 ; and lastly, the two moulds
in jig. 4.
SECTION VIII. — A Coxic Arch in a Cylindric Wall.
PROBLEM I.
To execute a semi-conic arch in a cylindric wall, supposing the vertex of the
cone to meet the axis of the cylinder. Given the interior and exterior diameters
of the wall, the length of the axis of the cone, and the diameter of its base.
TI) FUS'JD) TTI K J5F g'iPOITiE
r/ lo.
ir.irnnsiii, jv
n n.
MI GMT SMGTI(M MM MILAM E
L,
nr ir mison xr
12.
I'm'TinijAm I'^rAJLTLi
w.wirnsow jv
A CONIC ARCH IN A CYLINDRIC WALL.
129
Example I. — From the point O, fig. 1, Plate XII., with the radius of the in-
terior surface of the wall, describe the arc ABC, and from the same point O, with
the radius of the exterior surface, describe the arc D E F, and the area between
the arcs ABC and D E F will contain the plan of the wall.
Draw any line O p, and make O p equal to the length of the axis of the cone.
Through p draw tv perpendicular to Op. From p as s. centre, with the radius
of the base of the cone, describe the semicircle qr s meeting ^ in the points q
and s. Divide the arc q rs into as many equal parts as the arch-stones are to
be in number, that is, in this example, into nine equal parts. Through the points
of division draw the joint lines, which will of course radiate from the centre p.
The extradosal line tuv is here described, as we here suppose the cone to be of
an equal thickness, and consequently the axis of the exterior cone longer than
that of the interior.
From the points 1, 2, 3, &c., where the lower ends of the joints of the arch-
stones meet the intradosal arc, draw lines perpendicular to t v, meeting t v in the
points I, A:, I, m, &,c. From these points draw lines to the vertex of the cone at
O, meeting the arc D E, or plan of the wall under the arch, in the points a,b,c, d,
&c. Draw the lines a e, bfy c g, d h, &c., parallel to the chord D E, to meet op
in IV. In fig. 2, draw the straight line A B, in which take the point p near the
middle of it, and make p A, p B, each equal to the radius of the exterior surface
of the cylindric wall. Through the points A and B draw f g, f g, perpendicu-
lar to A B.
From the point p as a centre, with any radius, describe a semicircular arc, and
divide it into nine equal parts as before. Through the points of division draw
the radiating lines to meet f g in the points c,/, g, &.c. From fig. 1 transfer the
distances E to, ae,bf, eg, &,c., fig. 1, to p g', fig. 2, p r, ps, p t, &lc., on each side
of the point p. Draw the perpendiculars rk, s I, t m, &lc., to A B, which will in-
tersect with the radials p e, pf, p g, &c., in the points k, /, m, &c. ; through the
points k, /, m, &,c., on each side, draw a curve, and this curve will be the eleva-
tion of the intrados of the arch.
Fig. 3 exhibits another method by which the heights of the points k, /, m,fig. 2,
might have been found. This method is as follows : — Upon a straight line
a b, and from the point a, make a b\ a c, a d, a e, &c., and a fi respectively equal
to O i, O k, O /, &LC.,fig. 1. In fig. 3, draw the straight lines b g, ch, d i, e k,fo,
perpendicular to a b. Make bg,ch, c? i, e A:, respectively equal to the heights
il, k2, 13, m4. Draw the straight lines ag, a h, a i, a k, intersecting f o in the
points I, m, n, o.
In fig. 2, make r k, s I, tm,un, respectively equal to fl,fm,fn,fo,fig. 2,
and thus the points k, I, m, &c., are found by a different method, which is more
17
132
PRACTICAL MASONRY.
It will be necessary to work the arch-stones into prisms, of which the ends are
the sections of the stones in the right section of the arch, namely, the same as
the compartments adjacent to the curve in the elevation. The prisms being
formed, draw the figure of the soffit of the stone upon the surface intended for
the same. Then apply the joint-mould upon each face of the stone intended for
the joint, and draw the figure of the joints ; then reduce the end of the stone
which is to form a part of the face of the arch in such a manner that when the
arch-stone is placed in the position which it is to occupy, or in a similar situation,
a straight edge, applied in a horizontal position, may have all its points in contact
with the surface of the face of the stone now formed. The face being thus
formed, the conic surface must also be formed by means of a straight edge, in
such a manner that all points of the straight edge must coincide with the sur-
face when the straight edge is directed to the centre of the cone.
SECTION IX. — Construction of the Moulds for Spherical Niches, both with Radiat-
ing AND Horizontal Joints, in Straight Walls.
Whex niches are small, the spherical heads are generally constructed with ra-
diating joints meeting in a straight line which passes through the centre of the
sphere perpendicularly to the surface of the wall, when the w^all is straight ; but
when it is erected upon a circular plan, the line of common intersection of all the
planes of the joints is a horizontal line tending to the axis of the cylindric wall.
Niches of large dimensions will be more conveniently constructed in horizontal
courses, than with joints which meet in the centre of the spheric head ; since, in
the latter, the length and breadth of the stones are always proportional to the di-
ameter or radius of the sphere, and therefore, when the diameter is great, the
stones w'ould be difficult to procure.
I’he construction of niches depends also upon the nature and position of the
surface from which they are recessed ; namely, a spherical niche may be made
in a straight wall, either vertical or inclined ; or it may be constructed in a circu-
lar wall or a spherical surface, such as a dome.
This subject, therefore, naturally divides itself under several heads or branch-
es ; the principal are, a spherical niche in a straight wall, with radiating joints ; a
spherical niche in a straight wall, in horizontal courses ; a spherical niche in a
circular wall, with radiating joints ; a spherical niche in a circular wall, in hori-
zontal courses ; and a spherical niche in a spherical surface or dome.
\
I
. r f,
'4
/ .
V-' ■ A-
l^l 13.
K! Ij K!V.VT''IL)^ IDKA llj)'li)©3:{ Y a
/ Mi/ir
h r-*
r ^
"
NICHES, WITH RADIATING JOINTS.
133
SECTION X. — Examples of Niches, with Radiating Joints in Straight Walls, as in
Plate XIII., Fig. 1.
XicHES of very small dimensions will be easily constructed in two equal cubic-
al stones, hollowed out to the spherical surface, with one vertical joint ; the por-
tion of the spherical surface formed by both stones being one fourth of the entire
surface of the sphere.
Fig. '2 is the elevation, fig. 3 the plan, and fig. 4 the vei'tical section perpen-
dicular to the face of the straight wall of such a niche.
The first operation is to square the stone ; namely, to bring the head of each
stone to a plane surface, then the vertical Joints and the upper and lower beds to
plane surfaces at right angles with the surface which forms the head.
The two stones as hollowed out are shown at Xos. 3 and 4. To show how
they are wrought, we will commence with one of the stones after being brought
to the cubical form. Let this stone be No. 3. In the solid angle of the stone
formed by the head, the vertical joint and the lower bed meeting in the point p,
apply the quadrantal mould, Xo. 2, upon each side, so that the angular point of
the two radiants may coincide with the point p, and one of the radiants upon the
arris of the stone which joins the point p ; then if the face of the quadrantal mould
coincide with the surface of the stone, the other radiant line will also coincide,
because the angle of the mould and all the angles of the faces of the stone are
right angles.
By this means we obtain, by drawing round the curved edge of the mould, the
three quadrantal arcs ah c, a g h, and c i Ji. The superfluous stone being cut
away, the spherical surface will be formed by trial of the mould, Xo. 2.
Fig. 1, Plate XIV., is the elevation, and /?«•. 2 the plan, of a niche in a straight
wall.
The elevation, 1, not only shows the number of stones which must be odd,
and the number of radiating joints, which must in consequence be one less than
the number of stones, but also the thickness of these stones, and the moulds for
forming the heads and opposite sides.
The head of the niche being spherical, makes it a surface of revolution. It
follows, therefore, that the sections through the joints are equal and similar figures ;
hence, if all the joints were of one length, one mould would be sufficient for the
whole ; but since, in this example, they are of different lengths, every two joint-
moulds will have a common part ; and thus if the mould for the longest joint be
found, each of the other moulds will only be a part of the mould thus found.
In order to ascertain the mould for each joint, the longest being AD, fig. 1,
134
PRACTICAL MASONRY.
extending from the centre to the extremity of the stone upon one side of the
plan, the next longest is A F, extending from the centre to the extremity of the
keystone, and the shortest A G.
Upon P 1, make A F equal to A F^^, and A G equal to A G'. Perpen-
dicular to P Q draw D d, Ff,Gg, meeting the front line R S of the plan, fig. 2,
in the points d,f g^ intersecting the back line of the stone in the points m, n, o ;
then will No. 1, hike dm, be the mould for the first stone raised upon the plan,
hikefn the mould for the joint on each side of the keystone, /if the
mould for the first stone above the springing-line. These moulds are shown
separately at I., II., III., and identified by similar letters.
Nos. 1,2,3, exhibit the first, second, and third stones of the niche as if
wrought to the form of the spherical surface ; No. 3 being the keystone ; there-
fore the two remaining stones are wrought in a reverse order to the stones ex-
hibited at No. 1 and No. 2.
The first part of the operation is to work the stones into a wedge-like form, so
that the right section of these stones may correspond to the figures formed by
the radiations of the joints to the centre A,fg. 1, and by the horizontal and ver-
tical joints of the stones adjacent to those which form the niche ; for this pur-
pose, two moulds for each head will be necessary, namely, one whole mould must
be made for each stone, and one mould for the part .within the circle, which will
apply to every stone, in order to form the extent of the part within the recess ;
thus a mould formed to the sectoral frustrum E E' K' K in the elevation, fig 1,
will apply alike to all stones, as will be shown presently.
The next thing is to form the moulds K' K D S G^, K'' K' G^ T F'', and
K" K'' F'' F^'', of the heads ; the application of these moulds is as follows : —
Having wrought the under bed, the head and back of each stone, and having
formed a draught next to the edge of the bed, upon the side which is to lie upon
the cylindric part in the centre, at a right angle with the head, apply the mould
K'' K D S G', fig. 1, upon the head of the stone No. 1, so that the straight edge
K D may be close upon the bed of the stone, and draw by the other edges of
the mould thus applied the figure r'rdsg; and, in the same line rd, close to
the bed, apply the mould K' K E E', fig. 1 , and by the other edges of this mould
draw the figure rV e c'. Appl}' the mould K' K D S G' to the opposite or paral-
lel side of the stone, close to the bed, and draw a similar and equal figure as
was done by the same mould when it was applied to the head ; this done, work
the upper bed of the stone.
Proceed in like manner with the stones exhibited at No. 2 and No. 3, and sim-
ilarly with the stones on the left-hand side of the arch ; the stones No. 1 and
No. 2 answering to those on the right hand of the keystone.
ir, ir. m/*or> S'r.
ri u<.
Fu! . }
c II ws
Fiq 1.
I
/Y, 16 .
fWWiWVson SiC.
NICHES IN STRAIGHT WALLS.
135
In order to show the application of the moulds marked I., IL, III., at the bottom
of the plate, taken from the plan, /g-. 2; the mould I. applies to the under bed
of the stone No. 1 ; the next mould II. applies upon the upper bed of No. 1,
and upon the under bed of No. 2 ; and the mould III. applies upon the upper
bed of No. 2, and upon each side of the keystone. No. 3.
As every arch has both a right and left hand side, and as every joint is formed
by the surfaces of two stones, every mould has four applications, one on each of
the four stones.
In order to render these applications of the moulds I., II., III., as clear as possi-
ble, the corresponding situations of the points marked upon each stone by each
respective mould are marked by similar letters to those on the moulds I., II., III.,
or their correspondents on the plan, 2; namely, on the under bed of the
stone No. 1 will be found the letters h, i, k, e d, m, as in the mould I. ; upon the
under bed of No. 2 will be found h\ i', k', e', g, o' ; as also upon the upper bed
of No. 1, i',k', e,' g', and upon the right-hand side of the keystone, No. 3, will be
found the letters h", i", k”, e",/", n", as also similar letters upon the upper bed.
No. 2, to those of the mould III.
ARCH, WITH SPLAYED JAMBS.
To find the angles of the joints formed by the front and intrados of an ellipti-
cal arch, erected on splayed jambs.
No. 1, on fg. 3, is the place of the impost; No. 2, the elevation.
The impost A'B'C'D'E is the first bed ; fghik, the second ; Imnop, the
third ; qrstii, the fourth ; vwxyz, the fifth. The other beds are the same in
reverse order. The breadth of all these beds is the same as that of the arch
itself. The lengths k K, n P, s U, a: Z, of the front lines of the moulds of the
beds are respectively equal to the lines H F, N L, S Q, X V, on the face of the
arch. And also, hg, nm, s r, x tc, on the parts of the moulds equal to the cor-
responding distances H C, N M, S K, X W, on the face of the arch. The dis-
tances kf, pi, ug, rv, are equal to the perpendicular part AE of the impost.
SECTION XI. — Examples of Niches in Straight Walls with Horizontal Courses, as
IN Plate XIV., Fig. 1.
Let Jig. 2 represent a niche with horizontal courses. No. 1 being the elevation
exhibiting three arch-stones on each side of the keystone, and No. 2 the
plan, consisting of two stones, making together a semicircle, each being one
quadrant.
The heads of the stones in the wall, on the right-hand side of the arch, which
136
PRACTICAL MASONRY.
also form a portion of the concave surface, are ABODE, FDCGH M,
M G K L M, and the keystone L K K L. Round each of these figures circum-
scribe a rectangle, so that two sides may be parallel and two perpendicular to
the horizon ; thus, round the head of the stone ABODE circumscribe the
rectangle A N O E'; round the figure F D 0 G M I, the head of the second stone,
circumscribe the rectangle P Q R I, &,c.
Draw the straight lines am and ai,fig. 3, No. 1, forming a right angle with
each other ; from the point a as a centre, with the radius dbc, describe the arc
c c, meeting the lines a m and a i in the points c, c.
Let the quadrangular figure hgfe,^o. 1, be considered as the upper bed
of a stone, which, as well as the lower bed, is wrought smooth, these two sur-
faces being parallel planes at a distance from each other equal to the line A E
or CT),fig.2. Moreover, let mcc'bbdd be considered as a mould made to
the figure before described and laid flat on the upper bed of the stone in its true
position, the points c, c, of the mould being brought as near to the side A e as
will just leave a sufficient quantity of stone, in order to work it complete. By
the edges of the mould thus placed, draw the curve cc, the straight lines cm
and c i, and the rough edges ik and ml.
Perpendicular to the upper bed, and along the arc cc\ cut the stone so as to
form a surface perpendicular to the upper bed, and the surface thus formed will
necessarily be cylindric ; through each of the straight lines cm and c'l cut a
surface perpendicular to the said upper bed, and these surfaces will be the
planes of the vertical joints, and will be at a right angle with each other; then
with a gauge, of which the head is made to the cylindric surface, and which is
set to the distance OD, //^. 2, No. 1, draw the curve line dd on the upper bed
of the stone. Upon the lower bed of the stone, with the gauge set to the dis-
tance N B, draw the arc b b\
The thickness of the stone is exhibited at No. '2, fig. 3, the upper bed being
represented by the line n r, and the lower bed by the line q u, so that n r and
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CONSTRUCTION OF STONES FOR GOTHIC VAULTS. 153
the points B, C, D, E, have been found, and the compound line AB C DE F G
will be the line of joints corresponding to the point 5, fig. 2. Find the lines cor-
responding to the other joints in the same manner. Transfer the divisions in the
line u q to the base hne of Jig. 3, and draw lines perpendicular to the base as or-
dinates. Transfer the ordinates oi fig. 2 to their corresponding ordinate fig. 3,
and draw the curves which will complete the inner edge of the rib, fig. 3. In
the same manner find the curve of the ribs. Jigs. 4, 5, 6, &c., which stand over
the lines v L, icm, x n, 6cc.
Fig. 7 exhibits a part of the plan of a groin-ceiling, consisting of two severies
when the plans of the piers are squares, of which the angular points terminate in
the sides of the plan of each severy, and then we have only to find the diagonal
ribs and those upon the narrow side of the severy. It must, however, be observ-
ed, both in Jigs. 1 and 7, that only one of the curves which belong to arches of
the two sides of a severy can be given ; the other must be found in the same
manner as the curves of the intermediate ribs. In Jig. 7 the plan of the joints
has only two points of convergence, which are found by producing the side of
the square which forms the plan of the pillars, and the plan of the ridge-lines, till
they meet each other.
W'e shall now proceed towards the formation of the stones of the vaulting.
Plate XXL, Fig. 2. Let A B C 1) be the plan of one cjuarter of a severy, and
let li C and i f be the seats of two adjacent ribs, and let h ij j N C be the rib
which stands upon h C, and let k I in n be the plan of the soffit of a stone. Per-
pendicular to It C draw k ij and I J, and draw y g pai'allel to h C. Produce n k to
sand nin too. Draw / 1 > and Is respectively parallel to sn and n m. Draw
Ir perpendicular to Is; make Ir equal to gj and join s r. Draw lu per-
pendicular to sn ; and from s, with the radius si’, describe an arc meeting lu
in the point u. Draw u v and n v respectively parallel to s n and s u. Perpen-
dicular to 11 0 draw o q and in p. IMake o q and in p each equal to gJ, and
join 11 p and n q. Draw p t perpendicular to n q, meeting n q in the point t. To
form the winding surface of the inti-ados, first work the soffit as a plane surface;
on the plane surface describe the figure u s ii v. Make n w equal to ii t.
In Jig. 3 make the angle ab c equal to s n o, Jig. 2, and make the angle c b e,Jig.
3, equal to o ii q. Having the two legs cba, c b e, of a right-angled trehedral, find
the angle g h i, which the hypothenuse makes with the leg c b e. Secondly, form
the bed of the stone to make an angle at the arris-line n v with the surface usn v,
equal to the angle g hi, Jig. 3. Draw ic x upon the end of the stone thus formed
perpendicular to n w, and make w x equal to t p, and on the end of the stone draw
11 X. Join k u ; then the four points n, k, u, x, are the four angular points of the
20
154
PRACTICAL MASONRY.
soffit of the stone. The other end of the stone will be formed in a similar
manner.
On the nature and construction of Gothic ceilings.
Let A, B, C, D, Plate XXL, fig. 1 , be the springing-points, A C and B D the
plans of the groins disposed in the vertices of the angle of a rectangle, their planes
bisecting each other in the point e ; also let Q U and S X, passing through the
point e, and bisecting the angles A e B, B e C, C e D, D e A, be the plans of the
ridges of the Gothic arches, and let A E, A H, B J, B K, C M, C N, D P, D G, be
the springing-lines of the Gothic ceiling.
Moreover, let the four straight lines E G, H J, K M, N P, at right angles to
Q U and S X, be the plans of four right sections to each wing of the groined
vault.
From the point A: as a centre, with the radius kp, describe the arc hg ; and
let the springing-lines A E, D G, A H, J B, &c., be such as to meet respectively
in the points Q, S, &c.
To construct the ribs w'hich are at right angles to the ridge-lines, and of which
their plans are E G, H J, &c. Let us suppose that the given rib is E F G, standing
upon E G as its plan. Prolong A E and D G to meet each other in the point Q.
Divide the half-curve E F of the arch into as many equal parts as the number of
courses is intended to be in the ceiling on each side of the ridge-line of the in-
trados of the arch ; let us suppose that this number is six, and that h is the first
point of division from the bottom point E of the rib, the succession of parts being
E h, hi, &c. From the points h, i, &c., draw the straight lines hp, i q, &lc., per-
pendicularly to E G, meeting E G in the points p, q, &c. Through the joints
p, q, &LC., draw from the point Q the lines Q r, Q s, &c., meeting A C, the plan
of the groin, in the points r, s, &c., and perpendicularly to A C draw the straight
lines 7'j, s k, Slc. Make ?'j, s k, &c., each respectively equal to ph, q i, &cc . ;
through the points A,j, k, &c., draw the curve Aj k V for one half of the curve
of the groin rib ; the other half is symmetrical, and therefore the same curve in a
reversed order.
To find the rib H I J. Prolong A H and B J to meet each other in the point S,
and draw the lines r S, s S, &c., intersecting H J in the points t, u, &c. Draw
t n, ii 0, &LC., perpendicular to H J, and make tn, uo, &lc., respectively equal to
p h, qi,'&LC. Through the points H, n, o, &c., draw the curve H I, and H I will
be the curve of one half of the arch over the line H J for the plan.
Hence we see that the lines y h, k i, &c., prolonged, will meet the line Q R per-
pendicular to the plane A B C D in the points f, g, &.C., at the same heights, Q/,
Q^, &c., as p h, p i, &c., of the heights of the ordinates of the given rib. Since
both sides are symmetrical, one description will serve each of them.
CONSTRUCTION OF STONES FOR GOTHIC VAULTS. 155
To describe a Gothic isosceles arch to any width, height, and to a given verti-
cal angle.
Plate XX. Let AB, fig. 1, be the span or width of the arch ; m C, perpen-
dicular to A B, from the middle point m, the height ; and eCf the vertical angle
given by the tangents C e and C fi making equal angles with the line of height,
m C.
In this example, the points e and /, the lower extremities of the tangents, are
regulated by erecting A e and B /, each perpendicular to A B, and making each
equal to three fourths of the height-line, m C.
From the point A, towards B, make A k equal to A e or B/, that is, equal to
three fourths m C ; and from the point C, the vertex of the arch, draw C e per-
pendicular to CL In C i take C /, equal to A k, and join kl ; bisect klhy a. per-
pendicular, d i meeting C i in the point i ; join i k, and produce i k to g.
From the point i, with the radius i C, describe an arc C g, meeting the line ig
in the point g, and from the point k, with the radius kg, describe an arc g A, and
A g C will be the one half of the intrados of the Gothic arch required.
Produce C m to meet A: i in the point n, and in A B make m u equal to m k,
join n u, and prolong nu to t, and u n to o. Make n o equal to n L From the
centre o, with the radius o C, describe the arc C h, meeting ut in the point h, and
from u, with the radius u h, describe the arc h B, and BAG will be the other half
of the intrados.
Upon A B, prolonged both ways to p and s, make Ap and B s each equal toi
the length of each one of the arch-stones in a direction of a radius. \
From the point A: as a centre, with the radius kp, describe the arc p g, and
from the point i, with the radius ig, describe the arc gi', and pgr will be half of
the extrados of the arch.
In the same manner will be formed str, the other half of the extrados. The
arch- stones are divided upon the dotted line in the middle into equal parts, and
the point lines are drawn by the centres of the intrados and extrados of the arch.
%
REMARK. •
When the height of the arch is equal to or greater than half the span, and
when it is not necessary that the vertical angle should be given, the curves of the
intrados and extrados on the one side may be described from the same centre, as
also those of the other side from another centre.
The most easy Gothic arch to describe is that of which the height of the intra-
dos is such as to be the perpendicular of an equilateral triangle, described upon
the spanning-line as a base ; such is fig. 2, and these centres are the points to
which the radiating joints must tend.
156
PRACTICAL MASONRY.
Gothic arches seldom exceed in height the perpendicular of the equilateral
triangle inscribed in the intrados of the aperture ; but when the arch is surmount-
ed, and the height less than the perpendicular of the equilateral triangle made
upon the base, draw a straight line from one extremity of the base to the vertex,
and bisect this line by a perpendicular. From the point where the perpendicu-
lar meets the base of the arch, and with a radius equal to the distance between
this point and the extremity of the base joined to the vertex, describe an arc
between the two points, joined by the straight line, and the curve which forms
one side of the intrados will be complete. In the same manner will be formed
the curve on the other side (see fig. 3), so that by only two centres the whole of
the intrados will be formed.
Figs. 4 and 5 show the method of erecting another form of Gothic arches.
Fig. 4 represents the manner of inserting the stone in a straight wall, so as to
form a circular pointed arch.
Fig. 5 shows the manner of forming the same arch. Let B C be the base-line
of the arch ; find the centre A, of B C ; at A erect the perpendicular A D, the
intended height of the arch ; find i, the centre of A D, produce A D to a, and
make A a equal to A i ,* join B D, and divide it into five equal parts at 1, 2, 3, 4, 5.
Draw the line a 2 through the point e, produce a 2 to g, make g 2 equal to a 2,
and e and g will be the radiating points. From the point e, with the radius e B,
describe the arc B 2, and from the point g, with the radius g D, describe the arc
D 2, and B 2 will be the intrados of one portion of the arch, and D 2 the extra-
dos of the other corresponding portion of the arch. The extrados and intrados
of the remaining side may be found in the same manner.
ON ANCIENT WALLS.
157
CHAPTER V.
SECTION I. — Ancient Walls.
The ancients used several kinds of walls, in which more or less masonry was
always introduced. They had their incertain, or inserted walls, and also their re-
ticulated walls.
The uncertain or irregular walls are those where the stones are laid with their
natural dimensions, and their figure and size of course uncertain. Plate XXII.,
fig. 2. The materials rest firmly one upon another, and are interwoven together,
so that they are much stronger than the reticulated, though not so handsome.
In this kind of wall the courses were always level; but the upright joints were
not ranged regularly or perpendicularly to each other in alternate courses, nor in
any other respect correspondently ; but uncertainly, according to the size of the
bricks or stones employed. Thus our bricks are arranged in ordinary walls, in
which all that is regarded is, that the upright joints in two adjoining courses do
not coincide. Walls of both sorts are formed of very small pieces, that they may
have a sufficiency of, or be saturated with, mortar, which adds greatly to their
solidity.
To saturate or fill up a wall with mortar, is a practice which ought to be had
recourse to in every case where small stones or bricks admit of it. It consists in
mixing fresh lime with water, and pouring it, while hot, among the masonry in
the body of the wall.
The walls called by the Greeks isidomum, fig. 3, are those in which all the
courses are of equal thickness ; and pscudo-isidomum, or false, fig. 4, when the
courses are unequal. Both these walls are firm in proportion to the compactness
of the mass, and the solid nature of the stones, so that they do not absorb the
moistness of the mortar ; and, being situated in regular and level courses, the
mortar is prevented from falling, and thus the whole thickness of the wall is
united. In the wall called complecton, fig. 1, the faces of the stones are smooth,
the other sides being left as they came from the quarry, and are secured with
alternate joints and mortar ; the face of this wall was often covered with a coat of
plaster. This kind of building, called diamixton, fig. 5, admits of great expedi-
tion, as the artificer can easily raise a case or shell for the two faces of the work,
and fill the intermediate space with rubble- work and mortar. Walls of this kind,
consequently, consist of three coats ; two being the faces and one the rubble
core, which is the middle ; but the great works of the Greeks were not thus built.
158
PRACTICAL MASONRY.
for in them the whole intermediate space between the two faces was constructed
in the same manner as the faces themselves; and they besides occasionally intro-
duced diatonos, or single pieces, extending from one face to the other, to
strengthen and bind the wall, Jig. 5, a a. These different methods of uniting the
several parts of the masonry of a wall should be well considered by all persons,
who are intrusted with works requiring great strength and durability.
If the walls are isidomoi, and fastened together with iron, they are properly
called cramped, fig. 5, c c c. The net-work structure, fig. 6, was much used in
ancient Rome, and is beautiful to the sight, but is liable to crack, wherefore no
ancient specimens of this kind remain. Plate XXl\.,fig. 7, exhibits a species of
ancient wall which may be seen at Naples. There are two walls, A A, of square
stones, four feet thick ; their distance six feet. They are bound together by the
transverse walls B B, at the same distance. The cavity C C, left between,
s six feet square, and is filled up with rubble-stones and earth.
Fig. 8 represents a second kind, built of square stones ; this was called
pseitdo-isidomiim, D D ; to be seen now at Rome in the Temple of Augustus. The
third species is the uncertain, fig. 9 ; a specimen of which still remains at Pales-
trina, twenty miles east of Rome. Another kind, 10, which may be seen at
Sermione, upon the Lake of Garda, is a species of w ooden wall, E E, and is called
formcc ; it is stuffed with stone, mortar, See., at random. The planks being taken
away, the wall E E appears, and is called formaceous.
The fifth kind. Jig. 11 , are walls made of cement, G G, composed of rough
pebbles out of a river or from a rock ; sometimes of shell, as are the walls of
Turin in Piedmont. 'Phis kind of wall should be bound by three courses of
bricks, at the height of two feet, as H H.
The sixth kind is brick-work. Jig. 12, which, especially in the walls of a city,
or extraordinary building, is constructed like the diamixton,{ov the bricks appear,
1 1, and the rubbish lies concealed in the middle, K K. In the bottom there are
six courses of larger bricks ; then some less, at the height of three feet ; then
the walls are bound again with three courses of larger bricks ; an example of this
kind still remains in the Pantheon, and in the hot-baths built by Diocletian.
The seventh kind,yf^. 13, is net-work, L L, which Palladio did not approve
of, and to insure the strength of which he proposed to erect buttresses at the
angles M M, and to place transversely, or lengthwise, six courses of bricks at the
bottom, N N, and in the middle three courses, O O, whenever the net-work is
raised six feet.
The existing examples of Roman complecton, with partial cores of rubble-work
or brick, sufficiently prove its durability ; but that of the Greeks was worked
throughout the whole thickness of the wall in the same manner as the facing of
the fronts, as their temples now existing testify.
CONSTRUCTION OF BRICK ARCHES.
159
The thickness of walls should be regulated according to the nature of the ma-
terials, and the magnitude of the edifice. Walls of stone may be made one fifth
thinner than those of brick; and brick walls in the basement and ground stories
of buildings of the first rate should be reticulated with stones, to prevent their
splitting ; a circumstance which has been too much disregarded by our builders.
SECTION II. — Construction of Brick Arches.
Plate XXIII., fig. 1, represents a straight arch or aperture in a brick wall.
Describe an isosceles triangle on C D, the width of the arch, as a base-line, whose
vertex will be at a, produce a C to E, and a D to F, and E F will be the extra-
dos, and C D the intrados of the arch.
Divide C D and E F into the same number of equal parts, and make the bricks
to correspond with these parts.
Fig. 2 is a segment arch. Describe an isosceles triangle as in fig. 1, and
bisect C D in 6 ; from the point a, with the radius a D, describe the arc D 6 C,
and with the radius a C, produced from the point a, describe the extrados, and
C 6 D will be the intrados of the arch.
Fig. 5 is a semicircular arch ; the intrados of which is easily found by making
the semidiameter, or one half the width of the arch, the radius of the semicircle
beD.
Fig. 4 is a semi-elliptical arch, formed from three points. Divide D d, the width
of the arch, into three equal parts at the points B, b; from the centre A of D d,
erect the perpendicular Ae, and produce A e at pleasure; join B a, making B a
equal to A D ; produce a B to c ; at the point B, with the radius B c, describe the
arc e d ; join b a, and produce ba to C ; then, with the radius a c, at the point a,
describe the arc ceC\ and at the point 6, with the radius b d, describe the arc C d,
and D e d, the intrados of the intended arch, will be complete.
Figs. 3 and 6 show the construction of Gothic arches on the principles laid
down in Plate XXXlll., figs. 1 and 3.
Nos. 1 and 2 represent the application of inverted arches to the foundations of
brick wall. (See Foundations.)
SECTION III. — Bricklaying.
Bricklaying is the art of building with bricks, or the uniting them, by cement
or mortar, into various forms for particular purposes.
160
PRACTICAL MASONRY.
Bricks are laid in a varied but regular form of connection, or bond, as exhibited
in Plate XXIII. The mode of laying them for an eight-inch walling shown in
fig. 7 being denominated English bond, and fig. 8, Flemish bond. Fig. 9 is
English bond in a brick-and-a-half or twelve-inch walling; and fig. 10, Flemish
bond in the same. Fig. 11 represents another method of disposing Flemish
bond in a twelve-inch wall. Fig. 12, English bond in a sixteen-inch, or a two-
brick-thick wall ; and fig. 13, English bond in a two-and-a-half-brick-thick wall.
Fig. 16 is another brick bond, which is admired for its regularity and strength;
it is formed of brick and tiles, and connected with this fig. is the next course
above the tiles, composed of headers.
Figs. 14, 15, 17, and 20, represent square courses, in pairs, of Flemish bond.
In each pair, if one be the lower course, the other will be the upper course.
The bricks having their lengths in the thickness of the wall are termed head-
ers, and those which have their lengths in the length of the wall are stretchers.
By a course in walling is meant the bricks contained between two planes parallel
to the horizon, and terminated by the faces of the wall. The thickness is that
of one brick with mortar. The mass formed by bricks laid in concentric order,
for arches or vaults, is also denominated a course.
The disposition of bricks in' a wall, of which every alternate course consists of
headers, and of which every course between every two nearest courses of head-
ers consists of stretchers, constitutes English bond.
The disposition of bricks in a wall (except at the quoins) of which every alter-
nate brick in the same course is a header, and of which every brick between
every two nearest headers is a stretcher, constitutes Flemish bond.
It is, therefore, to be understood that English bond is a continuation of one kind,
throughout, in the same course or horizontal layer, and consists of alternate lay-
ers of headers and stretchers, as shown in the plate ; the headers serving to bind
the wall together in a longitudinal direction, or lengthwise, and the stretchers to
prevent the wall splitting crosswise or in a transverse direction. Of these evils
the first is the worst, and therefore the most to be feared.
It is supposed that the old English mode of brick-work affords the best securi-
ty against such accidents, as work of this kind, wheresoever it is so much under-
mined as to cause a fracture, is not subject to such accidents, but separates, if at
all, by breaking through the solid brick, just as if the wall were composed of one
piece.
The ancient brick-work of the Romans was of this kind of bond, but the ex-
isting specimens are very thick, and have three, or sometimes more, courses of
brick laid at certain intervals of the height, stretchers on stretchers, and headers
on headers, opposite the return wall, and sometimes at certain distances in the
ON BRICKLAYING.
161
length, forming piers, that bind the wall together in a transverse direction ; the
intervals between these piers were filled up, and formed panels of rubble or retic-
ulated work ; consequently great substance, with strength, were economically ob-
tained.
It will also be understood, Flemish bond consists in placing, in the same course,
alternate headers and stretchers ; a disposition considered as decidedly inferior in
every thing but appearance, and even in this the difference is trifling ; yet to ob-
tain it strength is sacrificed, and bricks of two qualities are fabricated for the pur-
pose ; a firm brick often rubbed, and laid in what the workmen term a putty -joint,
for the exterior, and an inferior brick for the interior, substance of the wall ; but,
as these did not correspond in thickness, the exterior and interior surface of the
wall would not be otherwise connected together than by an outside heading
brick, here and there continued of its whole length ; but, as the work does not
admit of this at all times, fiom the want of agreement in the exterior and interior
courses, these headers can be introduced only where such a correspondence
takes place, which, sometimes, may not occur for a considerable space.
Walls of this kind consist of two faces of four-inch work, with very little to
connect them together, and, what is still worse, the interior face often consists of
bad brick, little better than rubbish. The practice of Flemish bond has, notwith-
standing, continued in England, from the time of William and Mary, when it was
introduced, with many other Dutch fashions, and the workmen are so infatuated
with it, that there is now scarcely an instance of the old English bond to be
seen.
The frequent splitting of Myalls into two thicknesses has been attributed to the
Flemish bond alone, and various methods have been adopted for its prevention.
Some have laid laths, or slips of hoop-iron, occasionally, in the horizontal points
between the two courses ; others have laid diagonal courses of bricks at certain
heights from each other ; but the effect of the last method is questionable, as in
the diagonal course, by their not being continued to the outside, the bricks are
much broken where the strength is required.
The outer appearance is all that can be urged in favor of Flemish bond, and
many are of opinion, that, were the English mode executed with the same at-
tention and neatness that is bestowed on the Flemish, it would be considered as
equally handsome ; and its adoption, in preference, has been strenuously recom-
mended.
In forming English bond, the following rules are to be observed.
1st. Each course is to be formed of headers and stretchers alternately, as
2d. Every brick in the same course must be laid in the same direction ; but in
21
162
PRACTICAL MASONRY.
no instance is a brick to be placed with its whole length along the side of another ;
but to be so situated that the end of one may reach to the middle of the others
which lie contiguous to it, excepting the outside of the stretching course, where
three-quarter bricks necessarily occur at the ends, to prevent a continual upright
joint in the face-work.
3d. A wall, which crosses at a right angle with another, will have all the bricks
of the same level course in the same parallel direction, which completely binds
the angles, as shown by Jigs. 7, 9, and 12, Plate XXIII.
Figs. 14, 15, 17, and 20, are the method of forming square pier, as shown by
two courses, one laid on top of the other.
Fig. 1 1, a pair of courses in the English bond, of one foot four inches square,
or the length of two bricks.
Figs. 15, 17, and 20, are square piers in the Flemish bond ; 20 is two and a
half brick square ; 15 is a pier of three bricks in length to one side ; 15 is a pier
of the length of three and a half brick square ; 1 7 the length of two bricks square ;
1 4 is a pier of three length square.
The great principle in the practice of brick-work lies in the proclivity or cer-
tain motion of absolute gravity, caused by a quantity or multiplicity of substances
being added or fixed in resistible matter, and which, therefore, naturally tends
downwards, according to the weight and power impressed. In bricklaying, this
proclivity, chiefly by the yielding mixture of the matter of which mortar is com-
posed, cannot be exactly calculated ; because the weight of a brick, or any other
substance laid in mortar, will naturally decline according to its substance or qual-
ity ; particular care should be taken, therefore, that the material be of one regu-
lar and equal quality all through the building ; and likewise, that the same force
should be used to one brick as to another ; that is to say, the stroke of the
trowel, a thing or point in practice of much more consequence than is generally
imagined ; for if a brick be actuated by a blow, this will be a much greater
pressure upon it than the weight of twenty bricks. It is, also, especially to be
remarked, that the many bad effects arising from mortar not being of a proper
quality should make masters very cautious in the preparation of it, as well as the
certain quality of materials of which it is composed, so that the whole structure
may be of equal density, as nearly as can be effected.
Here we may notice a particular which often causes a bulging in large flank
walls, especially when they are not properly set off on both sides ; that is, the
irregular method of laying bricks too high on the front side ; this, and building
the walls too high on one side, without continuing the other, often causes defects.
Notwithstanding, of the two evils, this is the least ; and bricks should incline
rather to the middle of the wall, that one half of the wall may act as a shore to
ON BEICKLAYING.
163
the other. But even this method, carried too far, will be more injurious than
beneficial, because the full width of the wall, in this case, does not take its abso-
lute weight, and the gravity is removed from its first line of direction, which, in
all walls, should be perpendicular and united ; and it is further to be considered,
that, as the walls will have a superincumbent weight to bear, adequate to their
full strength, a disjunctive digression is made from the right line of direction ;
the conjunctive strength becomes divided ; and instead of the whole or united
support from the wall, its strength is separated in the middle, and takes two later-
al bearings of gravity, each insufficient for the purpose ; therefore, like a man
overloaded either upon his head or shoulders, naturally bends and stoops to the
force impressed ; in which mutable state the grievances above noticed usually
occur.
Another great defect is frequently seen in the fronts of houses, in some of the
principal ornaments of brick-work, as arches over windows, &c., and which is too
often caused by a want of experience in rubbing the bricks ; which is the most
difficult part of the branch, and ought to be very well considered. The faults
alluded to are the bulging or convexity in which the faces of arches are often
found, after the houses are finished, and sometimes a looseness in the key or cen-
tre bond. The first of these defects, which appears to be caused by too much
weight, is, in reality, no more than a fault in the practice of rubbing the* bricks too
much off on the insides ; for it should be a standing maxim (if you expect them
to appear straight under their proper weight) to make them the exact gauge on
the inside that they bear upon the front edges ; by which means their geometri-
cal bearings are united, and tend to one centre of gravity.
The latter observation, of camber arches not being skewed enough, is an egre-
gious fault ; because it takes greatly from the beauty of the arch, and renders it
insignificant. The proper method of skewing all camber arches should be one
third of their height. For instance, if an arch is nine inches high, it should skew
three inches ; one of twelve inches, four ; one of fifteen, five ; and so of all the
numbers between those. Observe, in dividing the arch, that the quantity con-
sists of an odd number ; by so doing, you will have proper bond, and the key
bond in the middle of the arches ; in which state it must always be, both foi
strength and beauty. Likewise observe, that arches are drawn from one centre ;
the real point of camber arches is obtained from the above proportion. First,
divide the height of the arch mto three parts ; one is the dimension for the skew-
ing ; a line drawn from that through the point at the bottom to the perpendicular
of the middle arch gives the centre ; to which all the rest must be drawn.
164
PRACTICAL MASONRY.
SECTION IV. — Foundations.
RULES TO BE OBSERVED IN LAYING FOUNDATIONS.
If a projected building is to have cellars, under-ground kitchens, &c., there
will commonly be found a sufficient bottom, without any extra process, for a good
solid foundation. When this is not the case, the remedies are to dig deeper ;
or to drive in large stones with the rammer ; or by laying in thick pieces of oak,
crossing the direction of the wall, and planks of the same timber, wider than the
intended wall, and running in the same direction with it. The last one to be
spiked firmly to the cross pieces to prevent their sliding, the ground having been
previously well rammed under them.
The mode of ascertaining if the ground be solid is by the rammer ; if, by strik-
ing the ground with this tool, it shake, it must be pierced with a borer, such as is
used by well-diggers ; and, having found how deep the firm ground is below the
surface, you must proceed to remove the loose or soft part, taking care to leave it
in the form of. steps if it be tapering, that the stones may have a solid bearing, and
not be subject to slide, which would be likely to happen if the ground were dug
in the form of an inclined plane.
If the ground prove variable, and be hard and soft at different places, the best
way is to turn arches from one hard spot to another. Inverted arches have been
used for this purpose with great success, by bringing up the piers, which carry
the principal weight of the building, to the intended height and thickness, and
then turning reversed arches from one pier to another, as shown in figs. 3 and 6,
Plate XXIII., Nos. 1 and 2.
In this case, it is clear that the piers cannot sink without carrying the arches, and
consequently the ground on which they lie, with them. This practice is excel-
lent in such cases, and should therefore be general, wffierever required.
Where the hard ground is to be found under the apertures only, build your piers
on those places, and turn arches from one to the other. In the construction of
arches some attention must be paid to the breadth of the insisting pier, whether it
will cover the arch or not ; for, suppose the middle of the piers to rest over the mid-
dle of the summit of the arches, then the narrower the piers, the more curvature
the supporting arch ought to have at the apex. When arches of suspension are
used, the intrudes ought to be clear, so that the arch may have the full ef-
fect ; but, as already noticed, it will also be requisite here that the ground on
which the piers are erected be uniformly hard ; for it is better that it should
be uniform, though not so hard as might be wished, than to have it un-
ON WALLS.
165
equally so ; because, in the first case, the piers would descend uniformly, and the
building remain uninjured ; but, in the second, a vertical fracture would take
place, and endanger the whole structure.
SECTION V. — Walls, &c.
The foundation being properly prepared, the choice of materials is to be con-
sidered. In places much exposed to the weather, the hardest and best bricks
must be used, and the softer reserved for in-door work, or for situations less ex-
posed.
If laying bricks in dry weather, and the work is required to be firm, wet your
bricks by dipping them in water, or by causing water to be thrown over them
before they are used. Few workmen are sufficiently aware of the advantage of
wetting bricks ; but experience has shown, that works in which this practice has
been followed have been much stronger than others, wherein it has been neglect-
ed. It is particularly serviceable where work is carried up thin, and putting
in grates, furnaces, &c.
In the winter season, so soon as frosty and stormy weather sets in, cover your
wall with straw or boards ; the first is the best, if well secured, as it protects the
top of the wall, in some measure, from frost, which is very prejudicial, particular-
ly when it succeeds much rain ; for the rain penetrates to the heart of the wall,
and the frost, by converting the water into ice, expands it, and causes the mortar
to assume a short and crumbly nature, and altogether destroys its tenacity.
In working up a wall, it is proper not to work more than four or five feet at a
time ; for, as all walls shrink immediately after building, the part which is first
brought up will remain stationary ; and when the adjoining part is raised to the
same height, a shrinkage or settling will take place, and separate the former from
the latter, causing a crack, which will become more and more evident as the
work proceeds.
In carrying up any particular part, each side should be sloped off, to receive the
bond of the adjoining work on the right and left. Nothing but absolute necessity
can justify carrying the work higher, in any particular part, than one scaffold ; for>
wherever it is so done, the w'orkmen should be answerable for all the evil that
may arise from it.
The distinctions of bond have already been shown, and we shall now detail
them more particularly ; referring to Plate XXIIL, in which the arrangement of
bricks of different thickness so as to form English Bond is shown, in figs. 7, 9,
12, and 13.
166
PRACTICAL MASONRY.
The bond of a wall eight inches is represented by fig. 7. In order to prevent
two upright or vertical joints from running over each other, at the end of the first
stretcher from the corner place the return stretcher, which is a header, in the face
that the stretcher is in below, and occupying half its length ; a quarter brick is
placed on its side, forming together six inches, and leave a lap two inches for the
next header, which lies with its middle upon the middle of the header below, and
forms a continuation of the bond. The three-quarter brick, or brick-bat, is called
a closer.
Another way of effecting this is by laying a three-quarter bat at the corner of
the stretching course ; for, when the corner head comes to be laid over it, a lap of
two inches will be left at the end of the stretchers below for the next header ;
which, when laid, its middle will come over the joint below the stretcher, and in
this manner form the bond.
/n a twelve-inch, or brick-and-half wall, {fig. 9,) the stretching course upon
one side is so laid, that the middle of the breadth of the bricks upon the opposite
side falls alternately upon the middle of the stretchers and upon the points be-
tween the stretchers.
In a two-brick wall, (fig. 12,) every alternate header, in the heading course, is
only half a brick thick on both sides, which breaks the joints in the core of the
wall.
In a two-brick- and-a-half wall, (fig- 13,) the bricks are laid as shown in fig. 6.
Flemish bond, for an eight-inch wall, is represented in fig. 8, wherein two
stretchers lie between two headers, the length of the headers and the breadth of
the stretchers extending the whole thickness of the wall.
In a brick-and-half Flemish bond, (fig. 10,) one side being laid as in fig. 2,
and the opposite side, with a half-header, opposite to the middle of the stretcher,
and the middle of the stretcher opposite the middle of the end of the header.
Fig. 5 exhibits another arrangement of Flemish bond, wherein the bricks
are disposed alike on both sides of the wall, the tails of the headers being placed
contiguous to each other, so as to form square spaces in the core of the wall for
half-bricks.
The face of an upright wall, English bond, is represented by fig. 18, and that
of Flemish bond by fig. 19.
SECTION VI. — The Construction of Chimneys.
Many able and scientific men have treated on this subject, but the result of
their observations serves only to prove, what is the result of every day’s experi-
ON THE CONSTRUCTION OF CHIMNEYS.
167
ence, namely, that rarefied air is lighter and less dense than cold air ; and that
it will ascend with a velocity proportionate to its rarefaction, unless obstructed by
other bodies.
Heat, that is generated by the combustion of fuel, exists under two distinct
forms ; and is known by the names of combustible and radiant heat. Combus-
tible heat partakes of smoke, and is carried off with it into the upper regions ;
while radiant heat is communicated to opposing bodies in contact wdth its rays.
It is stated by some, that combustible heat combined with air and smoke exists
in the proportion of four to one, compared to radiant heat ; but its correct pro-
portion has, perhaps, never been ascertained.
It is, however, certain, that very little radiant heat will escape from a smothered
combustion, while a dense smoke will very slowly ascend, and sometimes a por-
tion of it is discharged into the room, and the chimney is pronounced smoky,
while the epithets uttered against masons, on such occasions, would be more
properly applied to the builders of the fire.
As nature acts by certain laws, we may derive more profitable information by
a proper observance of them, than from accidental occurrences.
It is one of the laws of nature that rarefied air ascends, while cold or dense air
descends. On the same principle, water discharges itself most copiously through
a channel of a uniform and direct surface, on the same inclination. Therefore,
channels, that are obstructed by eddies and the discharge of other streams into
them, are impeded, and the velocity of the water diminished, so as often to pro-
duce what is called back-water for a considerable distance, which, when removed,
permits the water to flow with rapidity. Short bends and turnings also present
obstacles to the current or flow of water, by which whirlpools are often seen in
actual contact with the natural stream. The same observations may be applied
to rarefied air or smoke. Hence those flues will carry smoke the best which
arise perpendicularly in a uniform direction.
Angles and turnings present obstacles to the progress of the smoke, and should
be avoided as much as possible.
Particular attention should be paid to the formation of the throat of the chim-
ney. The dimensions of which should, in no case, exceed the number of square
inches contained in a horizontal section of the flue. It has been contended by
some that it should be smaller than this, while others have thought that it should
be larger; but experience has shown both of these opinions to be erroneous.
When the throat is smaller, the frequent rushes of cold air into it, from the open-
ing of doors, &.C., sends a gush of smoke into the room, by obstructing the up-
ward current of rarefied air.
When the throats are larger, eddies are formed in them, and the smoke, be-
168
PRACTICAL MASONRY.
coming dense by the steam of the fuel, chokes the flue, and instead of ascending
is puffed into the room.
Experience has shown the best construction to be that where the throat con-
tains as many square inches as a section of the flue. If the latter, for instance?
is one hundred and forty-four inches, the throat should be four feet long, and
three inches wide, nearly on a level with the mantel-bar, or at the top of the
opening of the fire-place, and graduated to the regular dimensions of the flue.
As represented in Plate XXVII., 3 and 4. In this plate, fig. 3 shows a
side perpendicular section of a chimney ; d, the partition -wall ; a, the throat ; b,
the breast ; c, the height of the graduation to form the regular flue ; E, the depth
of the jamb ; /, a trimmer to support the hearth in form of a segment arch.
Fig. 4 is the front elevation of fig. 3, representing the flues, fire-places, a hori-
zontal section at the heai'ths, as D E ; a section of the flues at the side of the fire-
places, I ; the core of the chimney, H ; the jambs, F ; the back of the fire-
places, G, with the inclined part of the back.
SECTION VII.-Fibe-Places.
In the selection of materials for the construction of fire-places, those should be
preferred which contain the least metallic ingredients. Metals are absorbents of
heat, and consequently occasion less heat to be radiated into the room, than ma-
terials of a different nature. Soapstone has been found to be one of the best
materials for this purpose. It contains but little metallic substance compared to
brick ; it is capable of a high degree of polish, and of being easily kept clean, by
which means the mys of heat are reflected into the room.
The proportions of a fire-place should in some degree be regulated according
to the size of the room which it is intended to warm.
If the room is eighteen feet in length, a fire-place of four feet three inches in
width, from jamb to jamb, and three feet in height, where the room is tw'elve feet
in the same direction, or one fourth of the height of the room, may, in general,
be considered of suitable proportions. The jambs should form an angle of one
hundred and thirty-five degrees with the back. See Plate XXVII., fig. 4. H,
the jamb, the back edge of which should be rabbeted and fitted to a groove
in the back, to keep it in its place ; F should be set plumb about two fifths of the
height of the back, F G ; G should be inclined forward to within seven inches of
the front line, allowing four inches for the thickness of the breast, and three inch-
es will remain for the passage of the smoke.
The Communication of Hot Air to Rooms. — This subject is worthy of attention.
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OF FIRE-PLACES.
169
inasmuch as the temperature of bed-chambers may be regulated by it as well
as the danger of fire, and the destructive and fatal effects of charcoal diminished.
This improvement may be adapted to common fire-places as well as to grates,
and the hot air carried from the first to the upper stories.
A little below the hearth in the first story, a small aperture is opened, of about
two inches square, through which to receive fresh air from the outside of the
house, into a cavity as large as can with convenience be made between the jambs
and the brick which form the wall of the chimney ; this cavity should be made
tight, with an aperture for the insertion of tubes of copper or tin, which are to be
inserted in the aperture with stops or slides, to regulate the quantity of air to
be admitted into the room. The air enters about two feet from the floor. By
turning the slide, the air is made to ascend into other apartments at pleasure.
Plate XXVII,, fig. 4, L is the generator of rarefied air; o, the tube, with a
slide at k ; the ascending pipe should be about four inches square ; m shows
its passage at the hearth.
Chimney-pieces are of various forms, as the fancy or taste of the proprietor
may dictate.
In Plate XX^'III., /ty. 1 is a Doric chimney-piece. Xo. 1, a section of the
jambs, back-facing, plinth, and pillars, drawn on a scale of lialf an inch to a
foot; Xo. 2, the shelf. Fig. 2 represents an Ionic chimney-piece; Xo. 1, a sec-
tion ; Xo. 2, the shelf; the line a shows a projection of the entablature; b, the
facins: under the entablature, drawn on a scale of half an inch to a foot.
SECTION VIII. — Warming by Steam and Hot Water.
Perkins's Patent is upon a principle that will bear investigation. The cooking-
range is made with a hollow cast-iron back, to hold from four to five gallons, with
copper pipes, introduced one at the bottom and one at the top ol this back, ex-
tending near three teet from the boiler, of one and a half to two inches calibie ;
then lead pipe of the same size to be carried to the rooms to be warmed ; there
lay a coil of about forty feet of pipe ; the coil may be inclosed in a chamber to
imitate a piece of furniture, thence carried to all the apartments in the house,
and returned to the under pipe connected with the hollow back, having the whole
tightly closed by soldering; then introduce an aperture at the highest point
made convenient for filling with water. When filled, close the aperture, when, by
the common use of the range, a current is produced in the water within the pipe^
passing from the upper pipe heated, and returning through the lower pipe to re-
new the revolution. There being no escape for steam, one filling will last a con-
22
170
PRACTICAL MASONRY.
siclerable time without renewing the water. Another, and, as we think, a still
better, method of warming houses, or other buildings, by means of heated water,
is that of Mr. Dexter, of this city. The following is a description of this meth-
od, as exemplified in the house of Mr. S. K. Williams, No. 68 Boylston Street.
A chamber of brick-work is built in the cellar, under the front entry, containing
three hundred and sixty cubic feet ; under, and near the centre, is a grate simi-
lar to those used for Bryent and Herman’s furnaces, over which is set a copper
boiler, holding thirty-two gallons. On one side of the boiler are fifty-four copper
tubes, four inches in diameter, and four feet long, set perpendicular, and resting
upon a table of brick -work, three and a half feet above the bottom of the cellar,
connected by six semi-cylindrical pipes, five feet in length, entering from the boil-
er, and parallel to each other, and uniting with the boiler at the bottom. The
upper ends of the tubes are united with each other in a transverse direction ;
also, in a semicircular form, a tube connecting with the boiler, near the top,
of the same size. The boiler is a cylinder, set upright above the brick-work,
four feet in height, and extends nearly to the height of the tubes. In the
entry, above, is set a copper vessel, with a lid to shut tight, containing sixteen
gallons ; a tube three fourths of an inch in diameter enters near the bottom,
passing down through the air-chamber into the boiler, for the purpose of filling by
a force-pump ; a stop-cock is inserted in the vessel at the top, to supply the boil-
er with cold water. The heated water is drawn from the same boiler for warm
baths, and from this air-chamber are funnels, registers, and dampers, entering
parlours, entry, ^/ ’J .
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OF FURNACES.
173
is so well understood by engineers, that they make the sides of their boilers pro-
ject so as to form the upper surface of the enveloping flue, by which means they
not only avail themselves of the lateral heat of the current, but also of that most
important property before stated, namely, the ascending.
The sides around the grate, shown at d, d, d, d, d, should rise in a sloping
direction, so as to accommodate the space to the rarefied air, after it has been
heated by the combustion of fuel; and as these sides will have to sustain the
greatest action of the heat, they being many times covered with the ignited fuel,
it is absolutely requisite that they should be formed of the best fire-bricks and set
in Stoarbridge clay, or fire-loam, mixed with ground clinkers from smiths’ forges,
which, when heated, will form a semi-vitrified mass that will bind and unite the
whole mass firmly together. In all cases where it can be admitted, the approach
to the narrowed passage to the current should be made to slope gradually up-
wards, which will assist to contract the current, like a funnel, at the same time that
such an effect is greatly assisted by changing the direction of the heated medium.
In the construction of fire-places, in which it is intended that the heated air
should be made to strike or impinge against any vessel in order to raise the tem-
perature of its contents, it will be of the greatest importance to have all the brick-
work done in the most thorough manner possible, as nothing can be more injuri-
ous than cracks or openings, which, by being connected with the flues, admit
cold air into the heated current, and thereby destroy, in a great measure, the
effect intended. To the practical man, who is aiming at eminence in his profes-
sion, we cannot too much enforce these observations, as they have been practical-
ly proved to be of the greatest importance.
Before concluding these observations upon the construction of this class of fire-
places, we wish most strenuously to impress upon our practical readers the mis-
taken and false economy of making fire-grates too small, a practice that most
completely defeats the principal object in view, namely, that of saving fuel.
A very little reflection will clearly show, that where the space for fuel is too
small, the want of room to spread the fuel will cause it to lay in such a compact
and solid state, that the gaseous parts will be distilled and pass along the flue
without being ignited, and by such means, instead of imparting heat by entering
into combustion, a precisely contrary effect will be produced. And if, on the
other hand, very small portions of fuel are frequently supplied, the opening of the
door of the fire-place so repeatedly will permit so much cold air to enter as to
essentially diminish the heating of the vessel and its contents, independently of
the great loss of time that will be required to keep up a steady heat.
There is also another circumstance of great importance, which must be admit-
ted into the consideration of this subject, namely, that where fire-places are made
174
PRACTICAL MASONRY.
sufficiently large, fuel of a much coarser description can be used, and a very
equable and economical heat may be produced ; for, in such cases, the cinders
and ashes from the common fire-grates, when mixed with a due proportion of
small coals, will be not only sufficient for creating a proper heat, but will not
require half the attendance that pure coals with a pinched fire-place will do.
We have been induced to make these observations, from a perfect convic-
tion of their practical utility, having frequently observed the great loss that
accrues, and the serious inconvenience that is sustained by many families who
have employed persons to set the ordinary kitchen copper, which is too frequent-
ly executed upon such bad principles, that a great portion of the advantages
and convenience of that very useful apparatus is lost. The length of the bars,
in most cases, should be about three fourths of the diameter of the bottom of
the boiler, and if they are loose bars they will be much better than a frame cut
with all the bars entire. The space between each bar should be about half an inch.
And it should be remembered that the flues of this kind of fire-places are as likely
as others to be clogged with soot, and therefore it will be very requisite to have
loose bricks, or stoppers, placed in proper situations, as shown at c,fig. 2, which
will give great facility in cleansing such flues, and frequently prevent danger from
fire in buildings where they may be erected. It may be necessary to state, that
the same precautions and directions ought to be observed in figs. 3, 4, and 5, as
in figs. 1 and 2. Figs. 3 and 4 represent a section and plan of a hot plate, fig. 3,
which is most generally of cast-iron, resting about an inch on the brick-work all
round, and a rim of wrought-iron should be fixed round the external brick-work,
to protect it from being broken or otherwise damaged. The bridge of fire-brick
ought to be built to within three-quarters of an inch of the plate, leaving that
distance between the bridge and the under part of the plate for the smoke and
heat to pass on the way to the chimney. The dotted line, in fig. 3, shows the
position of the flue and the chimney. Fig. 5 is the plan of the copper boiler, with
the bottom part contracted round the grate. The same rises at the opening in
the back, passes round the bottom, and then enters the chimney.
Fig. 5 is the representation of a charcoal -stove, which is composed of solid
brick- work, except it should so happen that a veiy large one should be wanted ;
then the wall may be built hollow and filled up with rubble. The grates are con-
structed of cast-iron, and placed four inches deep, with a vacuity under the floor
for the ashes to drop, whence they may be drawn out through the cavity left
in the front. Stoves of this description are used for stew-pans, chafing-dishes, &lc.
A rim of wrought-iron should be fixed round the brick-work at the top, about three
and a half inches deep, or a covering of soap-stone an inch and a half thick,
properly fitted ; the grates are of different sizes, according to the magnitude of
the building.
W.WM'ns/w h'r.
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OF FURNACES.
175
On the Method of fixing a Copper Boiler for Brewing. — Fig. 1, Plate XXXII.,
is a section through the upper vertical line in the middle of the copper ; fg. 2 is a
horizontal section of the copper taken under the bottom, and may be considered
as the plan of the brick- work immediately above the grate. This method offers
the least obstruction for the flame to play on both sides where it meets on the op-
posite side of the prop at A, and thence rises in a sloping direction towards the
back, which is shown by another section, fg. 3, the part at A being the partition,
as shown on the plan, fg. 2. Above the partition, A, the whole of the smoke
rushes into a chimney or tube ascending up the back of the brick-work, and is
discharged into the atmosphere at the top. This chimney is shown in the sec-
tion, fg. 3, which is taken at right angles to fig. 2, as exhibited by the plan,
fg. 4, which is the plan of the second, fig. 3. Fig. 6 is an elevation of the front,
showing the fire-place and the manner of suspending the door by means of
pulleys, which is balanced by a weight depending from the remote pulley ; the
top of the brick casing round the copper is entirely closed round the circumfer-
ence, as shown on the three sections at a a, a a, &cc. There is a similar ring of
brick-work which encompasses the circumference of the copper, and is also
shown on these sections, nX bb, b b, v>/? ,Vc
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CONSTRUCTION OF OVENS.
177
Stimpson^s Patent Radiating and Hot-air Ranges. — These ranges can be
set either with or without the bath-boiler. They can also be set with hot-air
fixtures, to heat an additional room with the same fire. They are manufactured
of various sizes, to accommodate families, victualling establishments, boarding-
houses, and taverns. They were originally invented more than fifteen years
since. Many thousands have been sold, and have been in use from ten to fifteen
years. They have been lately very much improved and newly patented, and
are believed to be, so far as economy of fuel, convenience of arrangement, dura-
bility, and facility for being repaired, are good qualities, the best ranges
now in use.
Plate XXXV. Fig. 1 is a front elevation of the range with bath -boiler ; fig. 2,
a horizontal section just below the boiler plates, showing the course of the flues ;
fig. 3 is a vertical section of the boiler and Hues connected with it ; fig. 4 is
a vertical section through the middle of the oven and of the fire-place, showing
the course of the oven -Hue.
In setting the range, first place the two sides, a, a, with the mantel, b, and
the grate, c, supporting the ends of the side grates with short pieces of wood,
till the brick is built up. Have these level and true, and be careful to leave space
enough between them to allow for the expansion of the plate which goes over the
fire. Now build up the brick-work level with the top of these sides, leaving the
Hues, as indicated by dddd. The brick back, which is usually set with them,
forms the back of the fire-place, and is bevelled at the top to fit the iron-work.
Two fire-bricks (headers) should be placed undereach of the side boiler holes, and
the rest of the space under the boiler holes filled with common brick, taking care
to leave a space of one inch underneath when the boilers are in. Now place the
oven frame, e, and the oven partition, y/; also the boiler casing, g ; the bottom of
this casing should be level with the top of the sides, a, a. Build up around the
oven with face brick. The space for the Hues at the side is shown by ledges on
the cast-iron partition, f f ; the space back of the oven should be an inch and a
quarter. Fill in around the boiler casing all solid, leaving a Hue at the top,
which should enter the main Hue.
SECTION IX. — O.v THE Construction of Ovens, Boilers, Fire-places, and of the
Setting of Copper.
The section of the roof of the oven, on the old principle, for the use of bakers
is usually of an oval figure, being arched over at the top in the figure of an
ellipsoid ; the sides and bottom are of brick, tiles, and lime, with a door in front ;
23
178
PRACTICAL MASONRY.
and at the upper part is an inclosed closet, with an iron grating for the tins to
stand on, called the proving-oven. To heat such ovens, fagots are introduced
and burnt to ashes, which are then removed, and the bottom cleaned out. This
operation requires some time, during which much of the heat escapes. A still
further length of time is required for putting in the bread, and unless much more
fuel is expended than is really necessary in heating an oven upon this principle,
it becomes chilled before the loaves are all set in, and they are, therefore, by this
means, very much injured.
To remedy this inconvenience, many ovens have latterly been built upon a
pavement, supported upon solid brick-work, with a door of iron, furnished with a
damper to carry off the steam as it rises, and heated with fossil coal. On one side
is a fire-place or furnace, with grating, ash-hole, and iron door, similar to that for
supporting a copper, with a partition to separate it from the oven, and open at
one end. Over this is a middling-sized copper or boiler, with a cock at the
bottom, and on one side of it is placed the proving-oven, the whole being faced
with brick and plaster.
When this oven is required to be heated, the boiler is filled with water, and,
the fire being kindled, the flame spreads around, in a circular direction, all over
its concavity, and renders it as hot as if heated with wood, without causing dirt
or ill smell, while the smoke escapes through an aperture, which may pass into the
kitchen chimney. When the coal is burnt to a cinder, there is no necessity for
removing it, as it prevents the oven from cooling while the bread is setting in, and
keeps up a regular heat till the door is closed. The advantages of an oven built
upon this principle are too obvious to require comment.
Plate XXXVII., in detail, is an improved plan of an oven on the new construc-
tion. It has been constructed by Mr. Elms, the architect, under whose direc-
tion it has been placed in various public buildings in different parts of Europe.
Fig. 1 is the plan of the oven ; the fire is put into the furnace A, and is
supported upon wrought-iron bars, which are fixed an inch and a half below
the level of the oven, to prevent the cinders from entering it; the outside of
the furnace is shut with two cast-iron doors (1, 2, in plan); the ashes fall into the
ash-pit beneath, B {fig. 2), the door of which is marked 3 in the elevation
{jig. 3). While the coals are burning, the mouth of the oven is inclosed only by
the curve cast-iron door, or blower, B, shown in the section of the oven {fig. 4)
and elevation {fig. 10), and which is so shaped in order to make a proper pas-
sage for the smoke to the flue, C ; this door, or blower, is not hung, but is put up
and taken away by hand, as may be required. When the oven is sufficiently
hot, the tender or baker stationed at the mouth, with an iron bar {fig. 5),
slides the cast-iron stopper D {figs. 1 and 6) to the angle F, where it stops, as
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CONSTRUCTION OF OVENS.
179
shown by the dotted line ; then, going to the mouth of the furnace, he hooks the
crooked part of the same iron bar 8) into the circular hole of the stopper H
(fig. 7), and pulls the fillet (fig. 8) into the frame of the furnace, upon which it
fits. This stopper is made to slide, but not in a groove, as the cinders might
. sometimes prevent its being shut. Fig. 8 represents an iron frame, to be fixed
round the mouth of the inside of the furnace ; the opening of the mouth should
be one foot two inches wide, and one foot high, and should be made to receive
the fillets of the stopper.
The door, K {fig. 4), is fastened to an iron chain, and is raised or let down at
pleasure by turning the lever L (figs. 4 and 10). In order to prevent the heat
from escaping w'hile the bread is putting in, the mouth of the oven must be made
as small as possible. To the handle of the lever is hung an iron pin, with a
chain, and over it is a semicircular iron plate, fastened to the wall, with five holes
to receive the pin, by which the height of the door, K, may be regulated at
pleasure.
When bread is baking, the curved door B, not being then wanted, is taken
away ; and the tw’o doors of the oven, with the two doors of the furnace, are
shut up. At the top of the furnace, M (fig. 4), is a small flue, about three inches
square, communicating with the flue of the oven. The use of this small flue is
to leave a passage for the sulphur that may remain in the ashes, and might injure
the bread while baking. The communication of this small flue of the oven is
opened or shut by means of an iron slider, N (fig. 10). Over the furnace is a
niche (fig. 3), with a boiler of hot water.
It has been observed, that, in ovens with this construction of the fire-place, it is
always proper to set the bars eight or ten inches in from the door ; by this means
a supply of coals will be kept warming before they are pushed forward into the
fire. The importance of this preparation is known to those who have attended
to the effect of every fresh supply of coals to the boilers of steam-engines, as it
instantly stops the boiling, unless this precaution is attended to. It also prevents,
in a great measure, the cold air getting in between the door and frame of the fire-
place, which frequently happens, from the difficulty of fitting iron doors to iron
frames.
Ovens, on the improved construction, will hold, according to their size, as fol-
lows : — eight feet wide and seven deep, ten bushels of bread; nine feet wide
and seven and one half feet deep, ten bushels ; ten feet wide and eight and a
half feet deep, twelve bushels.
Plate XXXVIII. This plate represents a baker’s oven, heated by coal ; this
oven has many advantages over any other ; its construction is simple, as will be seen
by reference to the plan; it economizes labor, as, when the oven is properly heated.
180
PRACTICAL MASONRY.
and with a proper quantity of coal and a well regulated fire, a tender stationed at
the mouth may, when the bottom of the oven is covered with bread, begin to take
out where he began to set in, and thus continue his labors as long as he pleases,
without being obliged, as in other ovens, to stop and renew the heat and clean
the bottom ; here the heat and labor is continually kept up, therefore one half of
the time may be saved. This oven is built of brick, as shown by figs. 1, 2, 3, and 4.
Fig. 1, front elevation ; a, the entrance to the cavity under the bottom ; b, the ash-
pit ; c, the door inclosing the grate ; d, the oven-door ; the doors and frames
made of cast-iron ; in the ash-pit door, a slide to regulate the draft of air. Fig. 2
is a horizontal section at the bottom of the oven ; the darts show the direction of
the heat and smoke, inclosed by a sheet-iron funnel twelve inches perpendicular,
and four inches on the horizontal line, leading from the coal-grate to the chimney-
flue, around the outside of the oven-hearth ; near the entrance to the chimney-flue
is a slide to retain the heat in the funnel at pleasure. Fig. 3, a horizontal
section under the hearth ; o, the entrance under the hearth ; b, the cavity ;
c, a centre pier to support the bottom of the oven, scale four feet to an inch.
Fig. 4, a vertical section ; a a, smoke-llue through which the heat passes from
the grate to the chimney-flue, through sheet-iron funnel nearly surrounding
the interior at the bottom, diffusing the heat into the oven , a space of time
usual for the ordinary heating at first will be all the hindrance for the day,
and the tender then takes his station at the oven-door; 6 6, cavity under the
bottom ; c, the arch of the oven ; d d, space above the arch, generally filled in
with a portion of sand to retain the heat.
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t
GLOSSARY
OF
ARCHITECTURAL TERMS.
Abacus. The upper member of the capital of I
a column whereon the architrave rests. Scam- ;
mozzi uses this term for a concave moulding in
the capital of the Tuscan pedestal, which, con-
sidering its etymology, is an error.
Abutment. The solid part of a pier from
which an arch springs.
Acanthus. A plant called in English Bear's j
Breech., whose leaves are employed for decorat- i
ing the Corinthian and Composite capitals. The
leaves of the acanthus are used on the bell of the
capital, and distinguish the two rich orders from
the three others.
Accompaniments. Buildings, or ornaments,
having a necessary connection or dependence, and j
which serve to make a design more or less com- ■
plete; a characteristic peculiarity of ornaments.
Accouplement. Among carpenters, a tie or
brace ; sometimes the entire work when framed.
Acroteria. The small pedestals placed on
the extremities and apex of a pediment.
Admeasurement. Adjustment of proportions ;
technically, an estimate of the quantity of ma-
terials and labor of any kind used in a building.
Alcove. The original and strict meaning of
this word, which is derived from the Spanish
alcoba, is that part of a bed-chamber in which
the bed stands, and is separated from the other
parts of the room by columns or pilasters.
Amphiprostyle. In ancient architecture, a
temple with columns in the rear as well as in the
front.
Amphitheatre. A double theatre, of an ellip-
tical form on the ground plan, for the exhibition
of the ancient gladiatorial fights and other shows.
Ancones. The consoles or ornaments cut on
the keys of arches, sometimes serving to support
busts or other figures.
Annulet. A small square moulding, which
crowns or accompanies a larger. Also, that fillet
which separates the flutings of a column. It is
sometimes called a List, or Listella, which see.
Antce. A name given to pilasters attached to
a wall.
Apophyge. That part of a column between
the upper fillet of the base and the cylindrical
part of the shaft of the column, which is usually
curved into it by a cavetto.
Arceostyle. That style of building in which
the columns are distant four, and sometimes five,
diameters from each other; but the former is the
proportion to which the term is usually applied.
This columnar arrangement is suited to the Tus-
can order only.
Arcade. A series of arches, of apertures, or
recesses, a continued covered vault, or arches
suj)ported on piers or columns instead of galler-
ies. In Italian towns, the streets are lined with
j arcades like those of Covent Garden and the
Royal Exchange.
Arch. An artful arrangement of bricks, stones,
or other materials, in a curvilinear form, which,
by their mutual pressure and support, perform
the office of a lintel, and carry superincumbent
weights, — the whole resting at its extremities
upon piers or abutments.
Arch-buttress, or Flying-buttress, (in Gothic
architecture,) an arch springing from a buttress
or pier, and abutting against a wall.
Archeion. The most retired and secret place
in Grecian temples, used as a treasury, wherein
were deposited the richest treasures pertaining to
the deity to whom the temple was dedicated.
Architect. One who designs and superintends
the erection of buildings.
Architrave. The lower of the primary di-
visions of the entablature. It is placed imme-
diately upon the abacus of the capital.
Astragal. From the Greek word for a bone
in the foot, to which this moulding was supposed
184
GLOSSARY OF ARCHITECTURAL TERMS.
to bear a resemblance. A small moulding,
whose profile is semicircular, and which bears
also the name of Talon, or Tondino. The astra-
gal is often cut into beads and berries, and used
in ornamental entablatures to separate the faces
of the architrave.
Attic. A term that expresses any thing invent-
ed or much used in Attica, or the city of Athens.
A low story erected over an order of architecture,
to finish the upper part of the building, being
chiefly used to conceal the roof, and give greater
dignity to the design.
Attic Base. See Base.
Attic Order. An order of low pilasters, gen-
erally placed over some other order of columns.
It is improperly so called, for the arrangement
can scarcely be called an order.
Auriel, or Oriel, (in Gothic architecture,) a
window projecting outwards for private confer-
ence : whence its appellation.
Balcony. A projection from the surface of a
wall, supported by consoles or pillars, and sur- ,
rounded by a balustrade.
Baluster. A small pillar, or pilaster, serving
to support a rail. Its form is of considerable
variety, in different examples. Sometimes it is
round, at other times square ; it is adorned with
mouldings and other decorations, according to
the richness of the order it accompanies.
Balustrade. A connected range of a number
of balusters on balconies, terraces around altars,
Ac. See Baluster.
Band. A term used to express what is gen-
erally called a Face, or Facia. It more properly
means a flat, low, square-pr^led member, with-
out respect to its place. Tliat from which the
Corinthian or other modillions, or the dentils, pro-
ject, is called the modillion band, or the dentil
band, as the case may be.
Bandelet. A diminutive of the foregoing term,
used to express any narrow flat moulding. The
tajniaon the Doric architrave is called its bandelet.
Banker. A stone bench on which masons cut
and square their work.
Banquet. The foot-way of a bridge raised
above the carriage-w’ay.
Barrel Drain. A drain of the form of a hol-
low cylinder.
Base. The lower part of a column, moulded
or plain, on which the shaft is placed.
Basement. The lower part or story' of a build-
ing, on which an order is placed, with a base or
plinth, die, and cornice.
Basil. A word used by carpenters, &c., to
denote the angle to which any edge-tool is ground
and fitted for cutting wood, Ac.
Basin, en Coquille, that is, shaped like a shell.
Basin is likewise used for a dock.
Basket. A kind of vase in the form of a
basket filled with flowers or fruits, serving to ter-
minate some decoration.
Bassilica. A town or court-hall, a cathedral,
a palace, where kings administer justice.
Basso-relievo, or Bass-relief. The represent-
ation of figures projecting from a back-ground,
without being detached from it. Though this
word, in general language, implies all kinds of
relievos, from that of coins to more than one
half of the thickness from the back-ground.
Bath. A receptacle of water appropriated for
the purpose of bathing.
Batten. A scantling of stuff, from two to six
inches broad, and from five eighths to two inches
thick, used in the boarding of floors ; also upon
walls, in order to secure the lath on which the
plaster is laid.
Batter. When a wall is built in a direction
that is not perpendicular.
Battlements. Indentations on the top of a
parapet, or wall, first used in ancient fortifica-
tions ; and afterw’ards applied to churches and
other buildings.
Bay, (in Gothic architecture,) an opening be-
tween piers, beams, or mullions.
Bay Window. See Auriel.
Bead and Flush Work. A piece of panel-
work, with a bead run on each edge of the in-
cluded panel.
Bead and Butt Work. A piece of framing in
which the panels are flush, having beads stuck or
run upon the two edges, with the grain of the
wood in their direction.
Bed-Mouldings. Those mouldings in all the
orders between the corona and frieze.
Billet-Moulding, (in Gothic architecture,) a
cylindrical moulding, discontinued and renewed
at regular intervals.
Boltel, (in Gothic architecture,) slender shafts,
whether arranged round a pier, or attached to
doors, windows, &c. The term is also used for
any cylindrical moulding.
Boss, (in Gothic architecture,) a sculptured
protuberance at the inteijunction of the ribs in a
vaulted roof.
Boss age. (A French term.) Any projection
left rough on the face of a stone for the purpose of
sculpture, which is usually the last thing finished.
Boultin. A name given to the moulding,
called the egg or quarter-round.
Broach, (in Gothic architecture,) a spire, or
polvgonal pyramid, whether of stone or timber.
Bracket, (in Gothic architecture,) a projection
to sustain a statue, or other ornament ; and some-
times supporting the ribs of a roof.
GLOSSARY OF ARCHITECTURAL TERMS.
185
Bulk. A piece of timber from 4 to 10 inches
square, and is sometimes called ranging timber.
Buttress, (in Gothic architecture*) a projection
on the exterior of a wall, to strengthen the piers
and resist the pressure of the arches within.
Cahling. The filling up of the lower part of
the fluting of a column with a solid cylindrical
piece. Flutings thus treated are said to be cabled.
Caisson. A name given to the sunk panels of
various geometrical forms, symmetrically dispos-
ed in flat or vaulted ceilings, or in soffits, gener-
ally.
Canopy, (in Gothic architecture,) the orna-
mented drip-stone of an arch. It is usually of the
ogee form.
Canted (in Gothic architecture.) Any part of
a building having its angles cut off, is said to be
canted.
Capital. The head or uppermost part of a
column or pilaster.
Carpenter. An artificer whose business is to
cut, fashion, and join timbers together, and other
wood for the purpose of building; tlie word is
from the French charpentier, derived from char-
peiitie, which signifies timber.
Carpentry, or that branch which is to claim
our attention, is divided into three principal heads,
viz.. Constructive, Descriptive, and Mechanical ;
of these. Descriptive carpentry shows the lines
or methods for forming every sj)ecies of work in
piano, by the rules of geometry ; Constructive
carpentry, the practice of reducing the wood into
particular forms, and joining the forms so produc-
ed, so as to make a complete whole, according to
the intention of the design ; and Mechanical car-
pentry displays the relative strength of the tim-
bers, and the strains to which they are subjected
by their disposition.
Cartouch. The same as modillions, except
that it is exclusively used to signify those blocks
or modillions at the eaves of a house. See Mo-
dill ion.
Caryatides. Figures of women, which serve
instead of columns to support the entablature.
Casement. The same as Scotia, which see.
The term is also used for a sash hung upon hinges.
Cauliculus. The volute or twist under the
flower in the Corinthian capital.
Cavetto. A hollow moulding, whose profile
is a quadrant of a circle, principally used in cor-
nices.
Cell. See Naos.
Cincture. A ring, list, or fillet, at the top or
bottom of a column, serving to divide the shaft
of the column from its capital and base.
Chamfer, ( in Gothic architecture,) an arch, or
jamb of a door, canted.
Chanip, (in Gothic architecture,) a flat surface
in a wall or pier, as distinguished from a moulding,
shaft, or panel.
Cinque-foil, (in Gothic architecture,) an orna-
mental figure with five leaves or points.
Column. A member in architecture of a cylin-
drical form, consisting of a base, a shaft or body,
and a capital. It differs from the pilaster, which
is square on the plan. Columns should always
stand perpendicularly.
Composite Order. One of the orders of ar-
chitecture.
Cope, Coping, (in Gothic architecture,) the
stone covering the top of a wall or parapet.
Corhel, (in Gothic architecture,) a kind of
bracket. The term is generally used for a con-
tinued series of brackets on the exterior of
a building, supporting a projecting battlement,
which is called a Corhel table.
Corinthian Order. One of the orders of ar-
chitecture.
Cornice. The projection consisting of several
members which crowns or finishes an entablature,
or the body or part to which it is annexed. The
cornice used on a [)edcstal is called the cap of
the pedestal.
Corona is that flat, square, and massy mem-
ber of a cornice, more usually called the drip or
larmier, whose situation is between the cymatium
above, and the bed -moulding below. Its use is to
carry the water, drop by drop, from the building.
Corridor. A gallery or open communication
to the diflerent apartments of a house.
Corsa. The name given by Vitruvius to a
platband or square facia, whose height is more
than its projecture.
Crenelle, (in Gothic architecture,) the opening
of an embattled parapet.
Crest, (in Gothic architecture,) a crowning
ornament of leaves running on the top of a
screen, or other ornamental work.
Crocket, (in Gothic architecture,) an ornament
of leaves running up the sides of a gable, or or-
namented canopy.
Cupola. A small room, either circular or poly-
gonal, standing on the top of a dome. By some
it is called a lantern.
Cushioned. See Frieze.
Cusp, (in Gothic architecture,) a name for the
segments of circles forming the trefoil, quatre-
foil, &c.
Cyma, called also Cymatium, its name arising
from its resemblance to a wave. A moulding
which is hollow in its upper part, and swelling
below.
Decagon. A plain figure, having ten sides
and angles.
24
186
GLOSSARY OF ARCHITECTURAL TERMS.
Decastyle. A building having ten columns in
front.
Decempeda. {Decern, ten, and pes, foot, Lat.)
A rod of ten feet used by the ancients in measur-
ing. It was subdivided into twelve inches in each
foot, and ten digits in each inch ; like surveyors’
rods used in measuring short distances, &c.
Decimal Scale. Scales of this kind are used
by draftsmen, to regulate the dimensions of their
drawings. I
Decoration. Any thing that enriches or gives
beauty and ornament to the orders of architecture.
Demi-Metope. The half a metope, which is
found at the retiring or projecting angles of a
Doric frieze.
Dentils. Small square blocks or projections
used in the bed-mouldings of the cornices in
the Ionic, Corinthian, Composite, and sometimes
Doric orders.
Details of an Edifice. Drawings or delinea- I
tions for the use of builders, otherwise called ^
working plans. j
Diagonal Scale is a scale subdivided into |
smaller parts by secondary intersections or ob-
lique lines.
Diameter. The line in a circle passing from i
the circumference through the centre. i
Diamond. A sharp instrument formed of that ;
. precious stone and used for cutting glass. '
Diapered (in Gothic architecture). A panel, or '
other flat surface, sculptured with flowers, is said j
to be diapered.
Diashjle. That intercolumniation or space be-
tween columns, consisting of three diameters ; — !
some say four diameters. I
Die, or Dye. A naked, square cube. Thus 1
the body of a pedestal, or that part between its '
base and cap, is called the die of the pedestal. |
Some call the abacus the die of the capital. '
Dimension. {Dimetier, Lat ) In geometry is
either length, breadth, or thickness.
Diminution. A term expressing the gradual ,
decrease of thickness in the upper part of a
column.
Dipteral. A term used by the ancici
press a temple with a double range of
in each of its flanks.
Dodecagon. A regular polygon, with twelve
equal sides and angles.
Dodecastyle. A building having twelve col-
umns in front.
Dome. An arched or vaulted roof springing
from a polygonal, circular, or elliptic plane.
Doric Order. One of the five orders of ar-
chitecture.
Dormant, or Dormer Windoir, (in Gothic ar-
chitecture,) a window set upon the slope of a roof
or spire.
ts to ex-
columns
Dooks. Flat pieces of wood of the shape and
size of a brick, inserted in brick walls, sometimes
called plugs or wooden bricks.
Door. The gate or entrance of a house, or
other building, or of an apartment in a house.
Dormitory. A sleeping-room.
Drawing, or Withdrawing- Room. A large
and elegant apartment, into which the company
withdraw after dinner.
Dressing-Room. An apartment contiguous
to the sleeping-room, for the convenience of
dressing.
Drip, (in Gothic architecture,) a moulding
much resembling the cymatium of Roman archi-
tecture, and used for the same purpose as a
canopy over the arch of a door or window.
Drops. See Gnttce.
Echinus. The same as the ovolo or quarter-
round ; but perhaps it is only called echinus
with propriety.
Edging. The reducing the edges of ribs or
rafters, that they may range together.
Elbows of a Window. The two panelled
flanks, one under each shutter.
Elevation. A geometrical projection drawn
on a plane, perpendicular to the horizon.
Embankments are artificial mounds of earth,
stone, or other materials, made to confine rivers,
canals, and reservoirs of water within their pre-
scribed limits ; also for levelling up of rail-
roads, Ac.
Emltrasure, (in Gothic architecture,) the same
as Crenelle, which see.
Encarpus. The festoons on a frieze, consist- .
ing of fruits, flow'ers, and leaves. See Festoon.
Entablature. The assemblage of parts sup-
ported by the column. It consists of three parts,
the architrave, frieze, and cornice.
Entail, (in Gothic architecture,) delicate can'-
ing.
Entasis. The slight curvature of the shafts
of ancient Grecian columns, particularly' the
Doric, which is scarcely perceptible, and beauti-
fully graceful.
Entresol. See Mezzanine.
Epistylum. The same as Architrave, which
see.
Eusiyle. That intercolumniation, which, as its
name would import, the ancients considered the
most elegant, namely, two diameters and a quarter
of a column. Vitruvius says this manner of ar-
ranging columns exceeds all others in strength,
convenience, and beauty.
Fagade. The face or front of any considerable
building to a street, court, garden, or other place.
Facia. A flat member in the entablature or
elsewhere, being in fact nothing more than a band
or broad fillet.
GLOSSARY OF ARCHITECTURAL T E R xM S .
187
Fa/ie, Phane, Vane, (in Gothic architecture,)
a plate of metal, usually cut into some fantastic
form, and turning on a pivot, to determine the
course of the wind.
Fastigium. See Pediment.
Feather-edged Boards are narrow boards
made thin on one edge. They are used for the
facings or boarding of wooden walls.
Festoon. An ornament of carved work, rep-
resenting a wreath or garland of flowers or leaves,
or both, interwoven with each other.
Fillet. The small, square member, which is
placed above or below the various square or
curved members in an order.
Finial, (in Gothic architecture,) the ornament,
consisting usually of four crockets, which is em-
ployed to finish a pinnacle, gable, or canopv.
Flank. The least side of a pavilion, by which
it is joined to the main building.
Flatning, in inside house-painting, is the mode
of finishing without leaving a gloss on the surface,
which is done by adding the spirits of turj)entine
to unboiled linseed oil.
Flight of Stairs is a series of steps, from one
landing-place to another.
Floors. 'J'hc bottom of rooms.
Flulings. Tlie vertical channels on the shafts
of columns, which are usually rounded at the top
and bottom.
Flyers are steps in a scries, which are parallel
to each other.
Folding- Doors are made to meet each other
from op])osite jambs, on which they arc hung.
Foliage. .\n ornamental distribution of leaves
or flowers on various parts of the building.
Foreshorten. term applicable to the draw-
ings or designs in which, from the obliquity of
the view, the object is re|)resented as receding
from the o[»posite side of the plane of the pro-
jection.
Foundation. That part of a building or wall
which is below the surface of the ground.
Foot. A measure of twelve inches, each inch
being three barleycorns.
Frame. The name given to the wood-work of
windows, inclosing glass, and the outward work
of doors or windows, or window-shutters, inclos-
ing panels; and in carpentry, to the timber-work
supporting floors, roofs, ceilings, or to the inter-
secting pieces of timbers forming partitions.
Fret. A kind of ornamental work, which is
laid on a plane surface ; the Greek fret is formed
by a series of right angles or fillets, of various
forms and figures.
Frieze, or Frize. The middle member of the
entablature of an order, which separates the ar-
chitrave and the cornice.
Frontispiece. The face or fore front of a
house ; but it is a term more usually applied to
its decorated entrance.
Fro7it. A name given to the principal interior
facade of a building.
Frustum. A piece cut ofi' from a regular
figure ; the frustum of a cone is the part that re-
mains when the top is cut ofi’ by an intersection
parallel to its base, as the Grecian Doric column
without a base.
Furrings are flat pieces of timber, plank, or
board, used by carpenters to bring dislocated
work to a regular surface.
Fust. The shaft of a column. See Shaft.
Gahle, (in Gothic architecture,) the triangu-
larly-headed wall which covers the end of a roof.
Gable Window, (in Gothic architecture,) a
window in a gable. These are generally the larg-
est windows in the composition, frequentl)^ oc-
cupying nearly the whole space of the wall.
Gablet, (in Gothic architecture,) a little gable.
See Canopy.
Gauge. In carpentry, an instrument to strike
a line parallel to the straight side of any board
or j)iece of stuff.
Gain. The bevelled shoulder of a binding ■
joist. ^
Gai-land, (in Gothic architecture,) an orna-*
mental band surrounding the top of a tower or
sjiiro.
Glyphs. The vertical channels sunk in the
triglyphs of the Doric frieze.
Gola, or Gala. The same as Ogee, which
see.
Gorge. The same as Cavetto, which see.
Gouge. A chisel of a semicircular form.
Granite. A genus of stone much used in
building, composed chiefly of quartz, feldspar,
and mica, forming rough and large masses of
very great hardness.
Groin, (in Gothic architecture,) the diagonal
line formed by the intersection of two vaults in a
roof.
Groined Ceiling. A surface formed of fliree
or more curved surfaces, so that every two may
form a groin, all the groins terminating at one
e.vtremity in a common point.
Groove, or Mortise. The channel made by a
joiner’s plane in the edge of a moulding, stile,
or rail, to receive the tenon.
Ground Floor. The lowest story of a building.
Ground Plane. A line forming the ground of
a design or picture, which line is a tangent to the
surface of the face of the globe.
Ground Plot. The ground on which a build-
ing is |)laced.
Grounds. Joiners give this name to narrow
I
188
GLOSSARY OF ARCHITECTURAL TERMS.
strips of wood put in walls to receive the laths
and plastering.
Gut 1(2, or Drops. Those frusta of cones in
the Doric entablature which occur in the archi-
trave below the taenia under each triglyph.
Gutters are a kind of canals in the roofs of
houses, to receive and carry off rain-water.
Halvi’ig. The junction of two pieces of tim-
ber, by inserting one into the other ; in some cases
to be preferred to mortising.
Hand-railing. The art of forming hand-rails
round circular and elliptic well-holes without the
use of the cylinder.
Hanging-Stile of a Door is that to which the
hinges are fixed.
Heel of a Rafter. The end or foot that rests
upon the wall-plate.
Helical Line of a Hand-rail. The line, or
spiral line, representing the form of the hand-rail
before it is moulded.
Helix. The curling stalk under the flower in
the Corinthian capital. See Cauliculus.
Hern. The spiral projecting part of the Ionic
capital.
Hexastyle. A building having six columns in
front.
Hood-mould (in Gothic architecture). See
Drip.
Hook-pins. The same as Draw Bore-pins, \o
keep the tenons in their place, while in the pro-
gress of framing ; the pin has a head or notch
in the outer end to draw it at pleasure.
Hypcethral. Open at top ; uncovered by a roof.
Hyperthyron. The lintel of a doorway.
Hypotracheliurn. A term given by Vitruvius
to the slenderest part of the shaft of a column
where it joins the capital. It signifies the part
under the neck.
Inchnography. The transverse section of a
building, which represents the circumference of
the whole edifice ; the different rooms and apart-
ments, with the thickness of the walls ; the dimen-
sions and situation of the doors, windows, chim-
neys ; the projection of columns, and every thing
that could be seen in such a section, if really
made in a building.
Impost. The layer of stone or wood that
crowns a door-post or pier, and which supports
the base line of an arch or arcade ; it generally
projects, and is sometimes formed of an assem-
blage of mouldings.
Inch. The twelfth part of a foot. For the pur-
pose of reckoning in decimal fractions, it is divid-
ed into ten parts or integers.
Inclined Plane. One of the mechanical pow-
ers, used for raising ponderous bodies, in many
instances of immense weight ; a declivity of a
hill, &c.
Insular Column is a column standing by itself.
Insulated. Detached from another building.
Intaglio. Any thing with figures in relief
on it.
Intercolumniation. The distance between two
columns.
Intrados. The under curved surface or soffit
of an arch.
Inverted Arches. Such as have their intrados
below the centre or axis.
Ionic Order. One of the orders of architec-
ture.
Jack Plane. A plane about 18 inches long,
to prepare for the trying plane.
Jack Rafters. The jack timbers, which are
fastened to the hip rafters and the wall-plates.
Jambs. The side pieces of any opening in a
wall, which bear the piece that discharges the
superincumbent weight of such wall.
Joinery, in building, is confined to the nicer
and more ornamental parts.
Jointer. A tool used for straightening and
preparing stufT for joints, Ac. This jointer is
about two feet eight or ten inches long.
Kerf. The slit or cut in a piece of timber, or
in a stone, by a saw.
King Post. The middle post in a section of
rafters.
Label, (in Gothic architecture,) a name for the
drip or hood-moulding of an arch when it is re-
turned square.
Lacunar, or Laquear. The same as Soffit.
Lantern, (in Gothic architecture,) a turret or
tower placed above a building, pierced either
with windows to admit light, or holes to let out
.steam.
Larmier. Called also Corona, which see.
Lath. A narrow slip of wood to inches
wide, to f inch thick, and four feet long, used
in plastering.
Leaves. Ornaments representing natural leaves.
The ancients used two sorts of leaves, natural and
imaginary'. The natural were those of the laurel,
palm, acanthus, and olive ; but they took such
liberties in the form of these, that they might
almost be said to be imaginary, too.
Level. A surface which inclines to neither
side.
Lining. Covering for the interior, as casing
is covering the exterior surface of a building.
Lintel. A piece of timber or stone placed
horizontally over a door, window, or other open-
ing.
List or Listel. The same as fillet, or annulet.
Listing. The cutting the sap-wood out from
both edges of a board.
Loop, (in Gothic architecture,) a small narrow
window.
GLOSSARY OF ARCHITECTURAL TERMS.
189
Louvre (in Gothic architecture). See Lan-
tern. *.
Luffer Boarding. The same as blind slats.
Machicolations, (in Gothic architecture,) small
openings in an embattled parapet, for the dis-
charge of missile weapons upon the assailants.
Frequently these openings are underneath the
parapet, in which case the whole is brought for- '
ward and supported by corbels.
Mechanical Carpentry. That branch of car-
pentry which teaches the disposition of the tim-
bers according to their relative strength, and the
strains to which they are subjected.
Mediceval Architecture. The architecture of
England, France, Germany, &c., during the
Middle Ages, including the Norman and early
Gothic styles.
Members. {Membrum, Lat.) The different parts
of a building; the different parts of an entabla-
ture ; the different mouldings of a cornice, Ac.
Metope. The square space between two tri-
glyphs of the Doric order. It is sometimes left
plain, at other times decorated with sculpture.
Mezzanine. A low story introduced between
two principal stories.
Minerva Polios. A Grecian temple at Athens.
Minute. The sixtieth part of the diameter of
a column. It is the subdivision by which archi-
tects measure the small parts of an order.
Mitre. .-\n angle of forty-five degrees, a half
of a right angle.
Modillion. An ornament in the entablature
of richer orders resembling a bracket.
Module. The semi-diameter of a column.
This term is only properly used when speaking
of the orders. As a semi-diameter it consists of
only thirty minutes. See Minute.
Mosaic. A kind of painting representing
cubes of glass, Ac., and is formed of different
colored stones, for paving, Ac. Specimens of
this kind have been found among the ruins of
antiquity.
Mouldings. Those parts of an order which
are shaped into various curved or square forms.
Mouth. The same as Cavetto, which see.
Mulule. A projecting ornament of the Doric
cornice which occupies the place of the modillion
in imitation of the ends of rafters.
Mullion, (in Gothic architectu^-e,) the frame-
work of a window.
Naked. The unornamented plain surface of a
wall, column, or other part of a building.
Naos, or Celia. The part of a temple within
the walls.
Newel. The solid, or imaginary solid, when
the stairs are open in the centre, round which the
steps are turned about.
Niche. A square or cylindrical cavity in a
wall or other solid.
Obelisk. A tall, slender frustum of a pyra-
mid, usually placed on a pedestal. The differ-
ence between an obelisk and a pyramid, inde-
pendent of the former being only a portion of
the latter, is, that it always has a small base in
proportion to its height.
Octastyle. A building with eight columns in
front.
Ogee, or Ogive. The same as Cyma, which
see.
Order. An assemblage of parts, consisting of
a base, shaft, capital, architrave, frieze, and cor-
nice, whose several services, requiring some dis-
tinction in strength, have been contrived or de-
signed in five several species, — Tuscan, Doric,
Ionic, Corinthian, and Composite ; each of which
has its ornaments, as well as general fabric, pro-
portioned to its strength and character.
Ordonnance. The arrangement of a design
and the disposition of its several parts.
Orle. (Ital.) A fillet or band under the
ovolo of the capital. Palladio applies the term
also to the plinth of the base of a column or
pedestal.
Ovolo. A moulding sometimes called a quar-
ter-round, from its profile, being the quadrant of
a circle. When sculptured it is called an Echi-
nus, which see.
Panel. A thin board having all its edges in-
serted in the groove of a surrounding frame.
Parapet. From the Italian parapetto, breast-
high. The defence round a terrace or roof of a
building.
Parastatce. Pilasters standing insulated.
Pavilion. A turret or small building generally
insulated, aYid comprised beneath a single roof.
Pedestal. The substruction under a column
or wall. A pedestal under a column consists of
three parts, — the base, the die, and the cornice or
cap.
Pediment. The low triangular crowning or-
nament of the front of a building, or of a door,
window, or niche.
Pend, (in Gothic architecture,) a vaulted roof
without groining.
Pendant, (in Gothic architecture,) a hanging
ornament in highly enriched vaulted roofs.
Pinnacle, (in Gothic architecture,) a small
spire.
Peripteral. A term used by the ancients to
express a building encompassed by columns,
forming, as it were, an aisle round the building.
Perist.ylium. In Greek and Roman houses, a
court, square, or cloister.
Perspective is the science which teaches us
190
GLOSSARY OF ARCHITECTURAL TERMS,
to dispose the lines and shades of a picture saas
to represent, on a plane, the image of objects ex-
actly as they appear in nature.
Piazza. A continued arch-way, or vaulting,
supported by pillars or columns ; a portico.
Pier. A solid between the doors or the win-
dows of a building. The square or other formed
mass or post to which a gate is hung.
Pilaster. A square pillar engaged in a wall.
Pile. A stake or beam of timbers, driven
firmly into the ground.
Pillar. A column of irregular form, always
disengaged, and always deviating from the pro-
portions of the orders ; whence the distinction
between a pillar and a column.
Platband. A square moulding, wliose pro-
jection is less than its height or breadth.
Plinth. The square solid under the base of a
column, pedestal, or wall.
Porch. An arched vestibule at the entrance
of a church, or other building.
Portico. A place for walking under shelter,
raised with arches in the manner of a gallerj" ;
the portico is usually vaulted, but has sometimes
a flat soffit or ceiling. This word is also used to
denote the projection before a church or temple
supported by columns.
Post. A piece of timber set erect in the
earth. Perpendicular timbers of the wooden
frame of a building.
Posticum. The back door of a temple ; also,
the portico behind the temple.
Principal Rafters. The two inclined timbers
which support the roof.
Profile. The contour of the different parts of
an order.
Projecture. The prominence of the mould-
ings, and members beyond tlie naked surface of
a column, wall, Ac.
Proscenium. The front part of the stage of the
ancient theatres, on which the actors performed.
Prostyle. A building or temple with columns
in front only.
Purlins. Pieces of timber framed horizon-
tally from the principal rafters to keep the com-
mon rafters from sinking in the middle.
Pycnostyle. An intercolumniation equal to
one diameter and a half.
Pyramid. A solid with a square, polygonal, or
triangular base, terminating in a point at top.
Quarter- Round. See Ovolo and Echinus.
Quatrefoil, (in Gothic architecture,) an orna-
ment in tracery, consisting of four segments of
circles, or cusps, within a circle.
Quirk Mouldings. The convex part of Gre-
cian mouldings, when they recede at the top,
formina a reenticent angle with the surface which
covers the moulding.
Quoins. The external and internal angles of
buildings or of their members. The comers.
Radius, in geometry, is the semi-diameter of a
circle, or a right line drawn from the centre to
the circumference ; in mechanics, the spoke of a
wheel.
Rails, in framing, the pieces that lie hori-
zontal ; and the perpendicular pieces are called
stiles, in wainscoting, &c.
Raking. A term applied to mouldings whose
arrises are inclined to the horizon.
Relievo, or Relief. The projecture of an
architectural ornament.
Resistance, in mechanics, that power which
acts in opposition to another, so as to diminish or
destroy its effect.
Reticulated Work. That in which the courses
are arranged in a net-like form. The stones are
square, and placed lozengewise.
Return. (Fr.) The continuation of a mould-
ing, projection, &c., in an opposite direction, as
the flank of a portico, &c.
Rib. (Sax.) An arched piece of timber sus-
taining the plaster-work of a vault, &c.
Ridge. The top of the roof which rises to an
acute angle.
Ring. A name sometimes given to the list,
cincture, or fillet.
Roman Order. Another name for the Com-
posite.
Rose. The representation of this flower is
carved in the centre of each face of the abacus
in the Corinthian capital, and is called the rose
of that capital.
Rustic. The courses of stone or brick, in
which the work is jagged out into an irregular
surface. Also, work left rough without tool-
ing.
Sagging. The bending of a body in the mid-
dle bv its own weight, when suspended horizon-
tally by each end.
Salon. .4n apartment for state, or for the
reception of paintings, and usually running up
through two stories of the house. It may be
square, oblong, polygonal, or circular.
Saloon. (Fr. ) A lofty hall, usually vaulted at
the top, with two stages of windows.
Sash. The wooden frame which holds the
glass in windows.
Scaffold. A frame of wood fixed to walls, for
masons, plasterers, &c., to stand on.
Scantling. The name of a piece of timber,
as of quartering for a partition, when under five
inches square, or the rafter, purlin, or pole-plate
of a roof.
Scapus. The same as Shaft of a column,
which see.
Scarf ng. The joining and bolting of two
H
GLOSSARY OF ARCHITECTURAL TERMS.
191
pieces of timber together transversely, so that
the two appear but as one.
Scotia. The name of a hollowed moulding,
principally used between the tori of the base of
columns.
Sever y, (in Gothic architecture,) a separate
portion of a building.
Shaft. That part of a column which is be-
tween the base and capital. It is also called the
Fust, as well as Trunk of a column.
Shank. A name given to the two intersticial
spaces between the channels of the triglyph in
the Doric frieze.
Shooting. Planing the edge of a board straight,
and out of winding.
Shoulder. The plane, transverse to the length,
of a piece of timber from which a tenon projects.
Shutters. The boards or wainscoting which
shut up the aperture of a window.
Sill. The timber or stone at the foot of a
window or door ; the ground timbers of a frame
which support the posts.
Skirtings. The narrow boards which form a
plinth round the margin of a floor.
Socle. A square flat member, of greater
breadth than height, usually the same as plinth.
Sojit. 'Phe ceiling or under side of a member
in an order. It means, also, the under side of the
larmier or corona in a cornice ; also, the under
side of that part of the architrave which does not
rest on the columns. See also Lacunar.
Sommer. The lintel of a door, winflow, &c. ;
a beam tenoned into a girder, to support the ends
of joists on both sides of it.
Spandrel, (in Gothic architecture,) the trian-
gular space inclosed by one side of an arch, and
two lines at right angles to each other, one hori-
zontal, and on a level with the apex of the arch, !
the other perpendicular, and a continuation of
the line of the jamb.
Spiral. A curve line of a circular kind, which
in its progress recedes from its centre.
Steps. The degrees in ascending a staircase.
Stereohala, or Stylohata. The same as En-
tasis.
Strap. An iron plate, to secure the junction
of two or -more timbers, into which it is secured
by bolts.
Stretching Course. Bricks or stones laid in a
wall with their longest dimensions in the hori-
zontal line.
Surbase. The mouldings immediately above
the base of a room.
Systyle. An intercolumniation equal to two
diameters.
Table, (in Gothic architecture,) any surface,
or flat member.
Tceni. A term usually applied to the lastel
above the architrave in the Doric order.
Templet. A mould used by bricklayers and
masons for cutting or setting the work ; a short
piece of timber sometimes laid under a girder.
Tenon. A piece of timber the thickness of
which is divided into about three parts ; the two
outside parts are cut away, leaving two shoulders,
the middle part projects, and, being fitted to a
mortise, is usually termed a tenon.
Terrace Roofs. Roofs which are flat at the
top.
Tetrastyle. A building having four columns
in front.
Torus. A moulding of semicircular profile,
used in the bases of columns.
Tracery, (in Gothic architecture,) a term for
the intersection, in various forms, of the mullions
in the head of a window or screen.
Transom, (in Gothic arcliilecture,) a cross
mullion in a window.
Trefoil, (in Gothic architecture,) an ornament,
consisting of three cusps in a circle.
Triglyph. The ornament of the frieze in the
Doric order, consisting of two whole and two
half channels, sunk triangularly on the plan.
Trimens. Pieces of timber framed at right
angles with the joints against the wall, for chim-
neys, and well-holes for stairs.
Trimmer. A small beam, into which are
framed the ends of several joists. The two joists
into which each end of the trimmer is framed are
called trimming-joists.
Trough Gutter. A gutter below the dripping
eaves, to convey the water to the pipe by which
it is discharged.
Trunk. See Shaft. When the word is ap-
plied to a pedestal it signifies the dado or die, or
body of the pedestal answering to the shaft of
the column.
Truss. When the girders are very long, or
the weight the floors are destined to support is
very considerable, they are trussed.
Tuscan. One of the orders of architecture.
Tusk. A bevel shoulder, made above a tenon,
to strengthen it.
Tympanum. The space inclosed by the cor-
nice of the sloping sides of a pediment, and the
level fillet of the corona.
Vault. An arched roof so contrived that the
stones or other materials of which it is composed
support and keep each other in their places.
Vestibule. An ante-hall, lobby, or porch.
Vice, (in Gothic architecture,) a spiral stair-
case.
Volute. The scroll which is appended to
the capital of the Ionic order.
1
a