- THE
- PREFACE.
- CONTENTS.
- Chapter I.
THE WALLS. STONE AND STONE-WORK. - Chapter II.
ON THE DURABILITY OF STONE BUILDINGS. - Chapter III.
THE WALLS. BRICKS AND BRICK-WORK. - Chapter IV.
THE ROOF. SLATES, AND OTHER ROOF COVERINGS. - Chapter V.
THE WOOD-WORK. GROWTH AND TRANSPORT OF TIMBER. - Chapter VI.
THE WOOD-WORK. CARPENTRY. - Chapter VII.
THE FIRE-PLACE. - Chapter VIII.
THE WINDOWS AND LEAD-WORK. - Chapter IX.
THE INTERIOR—PLASTERING AND PAPER-HANGING. - Chapter X.
THE INTERIOR—PAINTING AND GILDING. - Chapter XI.
A MODEL DWELLING-HOUSE. - CHAPTER XII.
FIRE-PROOF HOUSES. - Chapter XIII.
MISCELLANEOUS PROCESSES. - Transcriber’s Notes
The Project Gutenberg eBook of The Useful Arts Employed In The Construction Of Dwelling Houses, by Anonymous
www.gutenberg.orgTitle: The Useful Arts Employed In The Construction Of Dwelling Houses
Second Edition
Author: Anonymous
Release Date: March 16, 2022 [eBook #67636]
Language: English
Produced by: Charlene Taylor and the Online Distributed Proofreading Team at https://www.pgdp.net (This file was produced from images generously made available by The Internet Archive)
THE
USEFUL ARTS
EMPLOYED IN
THE CONSTRUCTION OF
DWELLING HOUSES.
LONDON:
JOHN W. PARKER, WEST STRAND.
MDCCCLI.
LONDON:
SAVILL AND EDWARDS, PRINTERS,
CHANDOS STREET.
[Pg iii]
PREFACE.
The dwellings of mankind, at first rude and simple in the extreme,
increase in complexity as their inhabitants advance in civilization.
Primitive dwellings are scarcely distinguished by signs of superior
skill or sagacity above the holes and nests of the lower animals. The
hut of the Hottentot may be considered as an inverted nest, and it is
certainly not more ingenious than the nests of many birds; but where
man constructs such a habitation for himself, he is invariably in a
low state of civilization. The wants of the bird are few and simple,
and the nest is a temporary abode annually constructed and annually
deserted: the wants of man, in a state of nature, are almost as
limited, and thus the Hottentot’s hut affords him as good a nest as he
desires. But when he steps forth into the rank which the Creator has
destined him to fill; when he feels that he is a responsible being, the
creation of an Almighty Power to whom worship is due; when he finds
that the productions of the earth are capable of being rendered useful
to him by the exercise of his ingenuity, and that his own mental powers
are capable of being developed by communion with, and by the assistance
of his fellow-men;—then the hut—the inverted nest—is no longer equal
to his necessities. He makes implements, and he must have a place
to shelter them; he cultivates grain, and he requires a store-house
for it; he collects and records the thoughts and the wisdom of his
predecessors, and he must have a roof to cover these precious mementos:
unlike other animals, he requires fire for the preparation
of the greater portion of his food; and his fire, as well as his
utensils, must be well defended from without:—in short, his wants are
so multiplied by the cultivation of his reason, that a house
has become necessary to him. The beasts of the field and the birds
of the air have certain natural instincts given to them which guide
them through life, and are perpetuated in their[Pg iv] offspring; the same
routine goes on race after race without the operation of what we term
improvement. Not so with man: he is a progressive being: he steps forth
beyond the limits of mere animal life, and has a mental existence, with
wants created by it, and depending on it; wants which are not known to
him when considered as a mere animal.
The building of houses has in all ages formed part of the employment of
man as he advanced from a state of mere barbarism to one of comparative
civilization. In devoting this little volume, therefore, to the subject
of the Application of the Useful Arts to the construction of Dwellings,
it is necessary to set a limit to so large a subject. A wigwam is
a house,—so is a palace, and examples of every possible gradation
between the two might be given. In order, then, to avoid the seeming
ambition of grasping the whole of this extensive subject we shall not
travel out of our own country; nor shall we ascend to the very highest,
or descend to the very lowest class of dwellings; but shall describe
the principal arts concerned in building a modern English house of
moderate rank. In so doing, we shall treat the subject under a few
simple heads, classified mainly according to the materials employed.
[Pg v]
CONTENTS.
|
| iii
| | —- | —- | |
Chapter I. The Walls—Stone and Stone-Work. | | |
Introduction, 9—Principal varieties of building stone, 10—On quarrying stone, 13—The application of electricity to the blasting of rocks, 17—Sawing the stones for the mason, 22—The processes of stone-masonry, 22. | | |
Chapter II. On the Durability of Stone Buildings. | | |
On the choice of a stone for building purposes, 27—Examination of a variety of buildings as to the durability of the stone employed therein, 28—The stone for the new Houses of Parliament—how chosen, 32—An easy method of determining whether a stone will resist the action of frost, 33—Directions for practising this method, 38. | | |
Chapter III. The Walls—Bricks and Brick-Work. | | |
Early use of bricks, 40—Floating bricks, 41—Making bricks by hand, 42—Varieties of bricks, 44—Tiles, 45—Making bricks and tiles by machinery, 46—The Marquis of Tweeddale’s method, 46—Another method, 47—The processes of bricklaying, 48—Mortar, 48—Defects of modern brick houses, 52. | | |
Chapter IV. The Roof—Slates and other Roof Coverings. | | |
Slate quarries, 54—The process of slating, 57—Paper roofs, 58—Their advantages, 60—Terrace roofs, 61—Asphalte roofs, 61—Scotch fir roofs, [Pg vi]61—Iron roofs, 62—Zinc and other metallic roofs, 63—Thatch roofs, 63. | | |
Chapter V. The Wood-Work—Growth and Transport of Timber. | | |
The oak as a timber tree, 66—The two chief varieties of oak, 67—Teak, 69—The fir and pine as timber trees, 69—The Norway spruce fir, 70—The Scotch fir, 73—Transport of timber from the forests, 77—Historical notices, 78—Rafts on the Rhine, 80—The slide of Alpnach, 81—Cutting the Norway deals, 83—The cutting and transport of Canadian timber, 83—Lumberers, 83—Saw-mills, 84—Rafts on the American rivers, 85—Miscellaneous kinds of timber, 86—Fancy woods, 87. | | |
Chapter VI. The Wood-Work—Carpentry. | | |
Sawing timber, 89—Scarfing or joining timber, 89—Trussing or strengthening, 90—Details of roof, 92—The mortise and other joints, 93—Distinction between carpentry and joinery, 95—The tools employed, 96—Glue, 98—A window sash, as an example of joiner’s work, 99—A second example of joiner’s work, 100. | | |
Chapter VII. The Fire-Place. | | |
Open fire-places, 102—Philosophy of a chimney, 103—Defects of open fires, 103—Remedies for some of these defects, 106—The register stove, 108—Smoky chimneys, 108—Causes of, and cure, 108—Close stoves, 111—The German stove, 112— Arnott’s stove, 113—Objections thereto, 115—Warming buildings by heated air, 116—The Russian stove, 116—Other methods, 117—Sir Stewart Monteith’s stove, 118—Warming buildings by steam, 118—Warming buildings by hot-water, 119—The high-pressure system, 120. | | |
Chapter VIII. The Windows and Lead-Work. | | |
Introduction of glass windows, 122—The manufacture of crown glass, 122—The manufacture of plate glass, 129—Cutting glass, 133—The process of glazing, 134—Sheet lead for roofs and cisterns, 135—Lead pipes, 136—The process of plumbing, 136—Solder or cement for metals, 139—Autogenous soldering, 140—Its advantages, 144. | | |
Chapter IX. The Interior—Plastering and Paper-Hanging. | | |
Plastering walls and ceilings, 148—Plaster and papier-maché ornaments for rooms, 149—Whitewashing and stuccoing, 150—Origin of paper-hangings, 150—The manufacture of paper-hangings, 151—Stencil, washable, [Pg vii]and flock paper-hangings, 153—The process of paper-hanging, 155. | | |
Chapter X. The Interior—Painting and Gilding. | | |
Reasons for painting a house, 158—Materials used in house painting, 158—Preparing the paint, 160—The process of painting, 160—Graining and marbling, 162—Gilding as an interior decoration, 164—The process of burnish-gilding, 165—The process of oil-gilding, 167—Gilding enriched ornaments, 168. | | |
Chapter XI. A Model Dwelling-House. | | |
The late Sir John Robison’s house at Edinburgh, 170—The Interior, 170—Warming,
170—Ventilating, 171—Lighting, 172—Gas cooking apparatus,
172—Flues, 173—Interior decorations by Hay, 173—A beau-ideal
English villa, 174—Situation, 175—Style, 175—Arrangement of the
interior, 176—The principal apartments, bed-rooms, &c., 177—The
kitchen, 179. |
|
|
Chapter XII. Fire-proof Houses. | | |
Hartley’s method of making houses fire-proof, 181—Earl Stanhope’s methods, 181—Pambœuf’s method, 183—Fire-proof paint, 184—Experimental trials, 184—Leconte’s method, 185—Varden’s method, 186—Frost’s method, 186—Loudon’s methods, 187—General remarks, 188. | | |
Chapter XIII. Miscellaneous Processes. | | |
Manufacture of nails, 188—Locks and keys, 188—Stoves and grates, 190—Bells, 190—Brass handles, ornaments, &c., 191—Preservation of timber, 191—Various methods, 193—Kyanizing, 194—Soluble glass, 194—Its uses in preserving timber, &c., 197—Veneering, 198—Brunel’s method of cutting veneers, 198—Russian method, 199—The process of veneering, 199—Manufacture of glue, 201—The house decorator of Italy, 201—Fresco painting as applied to the decoration of houses, 206—Nature and difficulties of the art, 207—Notices of the ancient custom of decorating walls, 208—The practice of fresco painting, 208—The Cartoon, 209—The preparation of the wall, 210—The process of painting, 210—The colours and implements, 211—A fresco painter at work described, 212—General remarks on fresco painting, 214. | | |
| 215
|
[Pg 9] The Useful Arts Employed in the Construction of Dwelling-Houses.
Chapter I.
THE WALLS. STONE AND STONE-WORK.
The material mainly employed in the construction of buildings depends
partly on the purpose for which the buildings are intended, and
still more, perhaps, on the prevailing geological character of the
surrounding country. In such a place as London, where there is an
immense mass of tenacious clay beneath the vegetable soil, and where
solid stone is not to be had, except by bringing it, at a great
expense, from a distance of many miles, clay seems to be the natural
material for dwellings; and thus we find that almost all the London
houses are built of brick formed of clay. In other parts of Great
Britain, such as Glasgow or Edinburgh, the case is very different; for,
in those places, clay is scarce, and stone is plentiful. There are
quarries not far from Edinburgh, and others within the very precincts
of Glasgow, where an abundant supply of good building-stone is obtained
at a very low rate. Hence it follows as a natural consequence, that
the houses in those two cities exhibit a large proportion of stone
structures; so much so, indeed, that an inhabitant of London, who is
accustomed to see stone appropriated only to large important public
buildings, is apt to imagine that the houses in the two northern cities
must necessarily be very costly. This is by no means certain, however,
for the builders in each city make use of those materials which may be
most available.
Whether stone form the main portion of the walls of a house, as in the
cases just named, or whether it is only used in smaller degree, as in
London houses, the operations by which it is worked and fitted are
pretty much the same; and we will therefore devote this chapter to a
brief description of the principal kinds of building-stone, followed by
an outline of the Mason’s operations.
[Pg 10]
Principal Varieties of Building-stone.
Granites are rocks which have been formed by the union of three
different minerals in a state of fusion; these, on cooling, have
crystallized and become distinct from each other in the mass. It is on
the varied proportions in which these three constituents are combined,
that the colour, hardness, durability, and beauty of the various
granites depend. The light-red and rose-coloured granites contain the
felspar in greatest abundance and in the largest crystals; but this
mineral varies in hue from the purest white to nearly black; it is the
ingredient most acted on by the atmosphere; the rock, therefore, which
abounds in it, though it may be more beautiful to the eye, and more
easily worked at first, is not so durable as that which contains it in
smaller crystals, and with a larger proportion of quartz. It is
to this last-named mineral that granite owes the sparkling appearance
which it presents when the sun shines on it; quartz is the hardest and
most imperishable of the three minerals which form the granite-rock.
The third, mica, is distinguishable from the other two by its
satiny, shining, dark hue, and is very apparent in the coarse-grained,
handsome stone of our own country, brought from Cornwall.
When the felspar is replaced by another mineral called
hornblende, the stone is of a dark-greenish hue, and the
component parts are in a finer form and less distinguishable from each
other. The Aberdeen granite is an example of this kind, which is more
durable than the former, though not so pleasing to the eye.
Granite occurs in all the larger mountain-ranges, and in isolated
masses in every country; not being a stratified rock, and being
excessively hard, it is difficult to quarry and get out in manageable
masses. Blasting with gunpowder is the mode usually employed in this
country; the pieces detached by this means are hewn roughly into form
on the spot by a small pickaxe. Aberdeen granite is quarried by cutting
a deep line some yards long, and placing strong iron wedges at equal
distances in this line; these wedges are struck in succession by heavy
hammers till the mass splits down. This, or analogous modes, may always
be employed when the rock approaches a slaty or stratified structure,
as is the case with some nearly related to granite. Another method
of detaching masses of rock, is by driving wooden wedges into a deep
fissure, either natural or artificial; the wedges are then wetted, and
the consequent expansion of the wood bursts the rock asunder.
As granite has always to be brought from a great distance to the spot
where it is wanted, because its natural localities[Pg 11] are far from the
places where edifices are usually constructed, and also on account of
its hardness, this rock is only used for important buildings, such
as bridges, markets, churches, &c., and not commonly even for these.
London and Waterloo bridges, Covent Garden and Hungerford markets, and
the York column in Pall Mall, are instances of its use in London.
The principal kinds of stone used in building are the
LIMESTONES, or calcareous rocks of the geologist; of
these it would be useless to describe or enumerate more than a few.
In our own country, the Portland stone, so called from its
principal quarries being in Portland Island, in Dorsetshire, holds the
first rank, and is that almost exclusively used in London for building,
and for the ornamental parts of edifices. It unites the qualities of
being easily sawn and worked, when lately quarried, and of subsequently
hardening by exposure to the air; it is close and even in its texture,
admitting of being wrought into delicate work, and receiving a very
smooth surface, which it will retain for a considerable period, though
it is surpassed in durability by many other rocks. It is said that
the Banquetting-house, Whitehall, was the first building in London in
which this stone was employed. Paul’s, Westminster and Blackfriars’
bridges, Newgate, and, indeed, most of the public buildings of the
metropolis, are examples of its use.
Bath-stone, so called from its being entirely used in the
neighbourhood of that city, is softer and far less durable than the
preceding. When recently quarried, it may be sawn with a toothed
saw, like timber, and can be carved with the greatest facility into
the richest ornaments; hence it is often employed, and, if sheltered
from the weather, is well adapted for such purposes, from its rich,
even cream colour; but though it hardens considerably by exposure,
it is acted upon, after a time, by the air, so as to render it very
perishable. The restoration of Henry the Seventh’s Chapel, Westminster,
is, unfortunately, made with this stone.
The two preceding, and many others, distinguished by names according to
the principal localities, as Oxford-stone, Ketton-stone,
&c., belong to what geologists term the Oolitic formation,
from the resemblance of some kinds of the rock to fishes’ roe, which
is observable in that we have last mentioned. They all agree in their
principal qualities.
Purbeck-stone, also from Dorsetshire, is used for steps, paving,
door-sills, and copings; it is coarser, harder, and less uniform in
texture than the foregoing, and not, therefore, calculated for fine
buildings, except for the purposes we have specified.
[Pg 12]
Yorkshire-stone resembles the last; it is used for the same
purposes, but especially for paving. The greatest part of the
foot-paths in the streets of London are laid with this or the preceding.
Rag-stone is obtained from quarries on the banks of the Thames,
Medway, &c. It was the stone chiefly used for building in ancient
London, and a great deal is still used for paving.
The lower chalk, which is of a grey colour, and contains masses
of flint, was formerly much employed for building in the south-western
counties of England; its good qualities are proved by the perfect state
of many old churches in that part of the kingdom, which are known to be
from seven to nine hundred years old. It is now only sparingly used in
farm-building and cottages, but it is consumed in vast quantities to
burn into lime for mortar and other purposes, and as a manure.
Belonging to the same family of calcareous rocks, and next in utility
to those we have just enumerated, though far surpassing them in beauty
and value, stand the endless varieties of Marbles, essentially
characterized by their crystalline texture, superior hardness, and by
the absence of shells or organic remains found so abundantly in all
other limestones. The name of marble is, however, popularly given to
many stones not possessing these characters, but which are hard enough
to be susceptible of a high polish, and are ornamental when so treated.
In this country the finer kinds of real marble are only sparingly
employed in the decorative departments of architecture, such as, for
chimney-pieces, slabs, hearths, capitals of columns in halls, saloons,
monuments, &c. The secondary kinds are also employed for similar
purposes, but more abundantly. The cold white statuary marble is not
adapted for out-of-door use in our foggy and cloudy climate, under the
influence of which it would soon become dingy and disagreeable, as is
proved by the total failure in the effect of the little triumphal arch
erected before Buckingham Palace. In Italy many ancient and modern
edifices are faced with white marble, and in that clear and pure
atmosphere they retain the beauty of the material for ages. The use to
which the finest marbles of Greece and Italy are applied in sculpture,
is familiar to every one.
The last class of rocks employed in building, in those localities
where they occur, are the Sandstones, silex, or flint, in
finely-comminuted particles agglutinated together, being their
principal ingredient; they constitute excellent building-stone, and are
abundantly used as such in the West of England.
[Pg 13]
On Quarrying Stone.
A quarry is an excavation made in the ground, or among rocks, for the
purpose of extracting stone for building, or for sculpture. The name
appears to have originated in the circumstance that the stones, before
they are removed to a distance, are first quadrated, or formed
into rectangular blocks.
The following may be taken as an example of the general operations
of quarrying building-stones. If the stone be vertically below the
surface of the ground, the quarrymen first remove the earth and surface
soil, and then dig a perpendicular shaft, or pit, to afford access
to the stone; but if, as frequently happens, the stone be within
the flank of a hill, or mountain, the quarrymen excavate horizontal
galleries into the hill, leaving pillars here and there to support
the superincumbent mass. Supposing a large quarry about to be opened
beneath the soil, the earth is first removed, and then a sort of
inferior stone called “rag,” which generally lies between the soil
and the good stone beneath. Large masses of available stone generally
consist of distinct strata lying close together in a kind of cemented
bulk, and the contiguous surfaces forming cleavages, greatly
assist the quarrymen in detaching blocks from the mass. The block is
always more easily separated in a direction parallel to these planes
of cleavage than in any other direction, and the operations are,
therefore, guided by this circumstance. The workmen drive a series of
iron wedges into the mass of stone parallel to the cleavage-planes;
and, after a few blows, a portion of the mass becomes separated in
that direction. They then measure off a portion equal to the intended
length and breadth of the stone, and drive their iron wedges similarly
in these directions, by which the piece is entirely severed from the
rocky mass. The cleavage-planes vary interminably in direction, so
that the quarrymen have to work in various positions, according to the
direction of stratification. The operations are more easily conducted
when the cleavage-planes are vertical, than in any other direction.
After the blocks have been severed, they are brought to an irregularly
square shape, by means of a tool called a kevel; and are finally
hoisted by cranes on to low trucks, and conveyed on tram-ways out of
the quarry; or else are hoisted to the surface of the quarry at once,
if the depth render that plan necessary.
In quarrying sandstone, and those rocks which consist of regular
layers, the pick, the wedge, the hammer, and the pinch, or lever, are
the chief tools. But for many kinds of[Pg 14] limestone, and for greenstone
and basalt, recourse is had to the more violent and irregular effects
of gunpowder. Indeed, some of the primitive rocks, such as granite,
gneiss, and sienite, could scarcely be torn asunder by any other means.
The great objection to blasting by gunpowder is, that the blocks are
broken irregularly, and much of the stone is wasted; but it has the
advantage of being simple in its application, and powerful in its
effects. The grains of powder are suddenly converted into a permanently
elastic air, occupying about four hundred and seventy-two times more
space than their own bulk. The elastic fluid expands with a velocity
calculated at the rate of about ten thousand feet per second; and its
pressure or force, when thus expanding, has been estimated as equal to
one thousand atmospheres, that is, one thousand times greater than the
atmospheric pressure upon a base of the same extent. By applying this
product to a square inch, upon which the atmosphere exerts a pressure
of about fifteen pounds, the elastic fluid of the gunpowder will be
found, at the moment of the explosion, to exert a force equivalent to
six tons and a half upon the square inch of surface exposed to it; and
that with a velocity which the imagination can hardly follow.
In boring a rock preparatory to blasting, it is necessary to consider
the nature of the stone, and the inclination or dip of the strata, in
order to decide upon the diameter, the depth, and direction of the hole
for the gunpowder. The diameter of the hole may vary according to the
nature of the rock, from half an inch to two and a half inches; and
the depth from a few inches to as many feet; the direction may vary
to all the angles from the perpendicular to the horizontal. The tools
used in this operation are very simple. The chisel, or jumper,
as it is called, varies in size according to the work to be performed,
and its edge is more or less pointed to suit the hardness of the
rock to be bored. If the hole is to be small and not deep, it may be
bored by a single person; with one hand he manages the chisel, which
he turns at every blow so as to cross the previous cut, and with the
other hand he strikes it with a hammer of six or eight pounds’ weight,
occasionally clearing out the hole by means of a scraper. But
when the hole is large and deep, one man in a sitting posture directs
the jumper, pours water into the hole, and occasionally cleans it out,
while two or three men, with hammers of ten or twelve pounds’ weight,
strike successive blows upon the jumper, until the rock is perforated
to the required depth.[Pg 15] To prevent annoyance to the workmen, a small
rope of straw or hemp is twisted round the jumper, and made to rest in
the orifice of the hole. When the holes are to be made to a greater
depth than about thirty inches, it is common to use a chisel from six
to eight feet in length, pointed at both ends, having a bulbous part
in the middle for the convenience of holding it; it thus becomes a
kind of double jumper, and is used without a hammer, with either end
put into the hole at pleasure. The workmen holding this jumper by the
bulbous part, lift it, and allow it to drop into the hole by its own
weight, and by this simple operation, a hole to the depth of five feet
and upwards is perforated with ease and expedition. When the boring
is completed, the fragments are carefully removed, and the hole is
made as dry as possible, which is done by filling it partially with
stiff clay, and then driving into it a tapering iron rod, called the
claying bar, which nearly fills it. This, being forced in with
great violence, drives the clay into all the crevices of the rock, and
secures the dryness of the hole. Should this plan fail, tin cartridges
are used: these are furnished with a stem or tube, as shown in the
following figure, through which the powder may be ignited. When the
hole is dry, the powder is introduced, mixed sometimes with quicklime,
which, it is said, increases the force of the explosion. A long iron
or copper rod, called the pricker, is then inserted amongst
the powder, and is afterwards withdrawn, when the priming powder is
introduced. The hole is filled up with burnt clay, pounded brick,
stone, or any other substance not likely to produce a spark during the
ramming. This is called the tamping. In filling up the hole,
the chief danger is the production of a spark among the materials,
a circumstance which has occasioned the most fatal and distressing
accidents to quarriers. Prickers and rammers of copper, or of bronze,
have been employed, but their greater expense, and liability to twist
and break, have prevented their general introduction.
The quarrier is, of course, accustomed to suppose that the more firmly
he rams in the powder, the greater will be the resulting effect. It
is, however, a curious property of sand, that it fills up all the void
spaces in the tube or hole, and for some rocks entirely supersedes the
necessity of ramming and pricking.
When the hole is fully charged with the powder and wadding, the pricker
is withdrawn, and the small tubular space, or vent-hole, which it
leaves, is sometimes filled up[Pg 16] with powder; but, for the sake of
economy, it is more common to insert straws filled with powder, and
joined together, so as to reach the required depth. The lower straw is
one terminating in the root part, where a natural obstruction occurs,
or it is artificially stopped with clay to prevent the powder from
being lost. The lower part of the priming straw is pared quite thin,
so as to insure the inflammation of the charge of powder in the hole.
Sometimes the fire is conveyed by means of the large and long green
rushes, which grow in marshy ground. A slit is made in one side of the
rush, along which the sharp end of a bit of stick is drawn, so as to
extract the pith, when the skin of the rush closes again by its own
elasticity. This tube is filled up with gunpowder; it is then dropped
into the vent-hole, and made steady with a bit of clay. This being
done, a slow match, called a smift, consisting generally of a
bit of soft paper, prepared by dipping it into a solution of saltpetre,
is carefully applied to the priming powder. When this match is about
to be fired, the quarriers usually blow a horn or ring a bell, to give
notice to all around them to retire. The explosion commonly takes
place in about a minute; the priming first explodes, attended only
with flame; a short interval of suspense commonly ensues; the eyes of
the bystanders being anxiously directed towards the spot; the rock is
instantly seen to open, when a sharp report or detonating noise takes
place, and numerous fragments of stone are observed to spring into the
air, and fly about in all directions, from amidst a cloud of smoke. The
quarrier then returns with alacrity to the scene of his operations.
The accompanying figure shows the plan of blasting the rock, and a
section of the hole ready prepared for firing. The portion of the rock
to be dislodged by the explosion is that included between A and B.
The charge of powder is[Pg 17] represented as filling the bore to C, from
which point to the top, the hole is filled up with tamping. The
smift is represented at D.
In the year 1831, a patent was taken out by Bickford, of Tucking
Mill, Cornwall, for an invention called “the Miner’s Safety Fuse.”
It consists essentially of a minute cylinder of gunpowder, or other
suitable explosive mixture, inclosed within a hempen cord, which
is first twisted in a peculiar kind of machine, then overlaid to
strengthen it; afterwards it is varnished with a mixture of tar and
resin to preserve the powder from moisture, and finally is coated with
whitening to prevent the varnish from sticking to the fingers, or the
fuses to one another. These fuses are said to have been used with good
effect, and to have greatly diminished the number of accidents.
The application of Electricity to the Blasting of Rocks.
Perhaps the greatest modern improvement that has been made in blasting
rocks has been by the introduction of the galvanic battery. It is
well known that by closing the circuit of a voltaic current by means
of thin platinum wire, or by fine iron or steel wire, the platinum
becomes red-hot, and the iron or steel becomes instantly fused. All,
therefore, that is necessary is to connect the two terminal wires of
a voltaic battery by means of a fine wire of platinum or iron, and to
bury this in gunpowder contained in a tin canister, or a fuse connected
with a deposit of gunpowder. This was the method adopted by Colonel
Pasley in removing the Royal George, which lay sunk at the bottom of
the water at Spithead. Canisters of gunpowder, sometimes to the extent
of three thousand pounds’ weight, were employed, and securely deposited
in the sunken vessel, by workmen who descended in the diving-bell; the
terminal wires of the battery, connected as above stated, having been
previously inserted in the canisters, and these wires being extended
to a great distance, the explosion took place the instant they were
connected with the voltaic battery. After the vessel was thus blown
to pieces by repeated explosions, divers descended to clear away the
wreck, and to attach guns, &c., to chains let down from a ship above,
and which were then hauled up by means of a crane.
Morgan, in the , describes a
fuse or cartridge which he has used with success in connexion with the
voltaic battery. This cartridge is prepared by[Pg 18] joining two pieces of
clean copper wire to the ends of a fine steel wire, about one quarter
of an inch in length, by means of waxed silk; a thin piece of wood
is then spliced to both copper wires, to protect the steel wire from
accidents, and to enable the maker to introduce it easily into a quill
or small paper tube, which is to form the cartridge. This tube is
filled with fine gunpowder, and made air and water-tight. Another piece
of wood is then attached to this arrangement, and one of the copper
wires is bent over so as to form an angle with the straight wire.
When it is required to use this cartridge, the copper wires are rubbed
with sand-paper, and twisted round the wires of the voltaic battery.
The cartridge is then placed deep in the hole made to receive the
gunpowder, and the charge is fired from any distance.
Morgan found this arrangement very useful in removing stumps of
trees; but one of his applications of it was curious and novel: he
exploded some powder in a pond at the depth of ten feet, with the
battery at the distance of two hundred and ten feet; the explosion,
which was instantaneous, had the effect of killing a large eel; and “I
have no doubt,” says Morgan, “that wild-fowl will yet be killed by
means of shells placed at low-water on the banks where they feed; and
by means of long connecting wires, the shells can be made to explode
simultaneously among the birds.”
But the grandest application of gunpowder and the voltaic battery to
the blasting of rocks, was made in the month of January, 1843, at
Dover. It was determined by these means to attempt the removal of an
enormous mass of the cliff facing the sea, which formed an obstruction
to the line of railroad. A portion of the cliff which was penetrated
by the tunnel made through Shakspeare’s Cliff gave way, about two
years previously. About fifty yards of the tunnel were carried away,
and a clear space was thus formed for the line of railroad, with the
exception of a projecting point, which, prior to the slip alluded to,
was the extremity of the part of the cliff pierced by the tunnel, and
to remove which was the object of the operation in question.
To clear away this mass by the tedious process of manual labour, would
have cost above twelve thousand pounds; and this consideration, as
well as the time that would have been lost, induced Cubitt, the
engineer, to try the bold expedient of blowing it away with gunpowder.
“It cannot be denied,” remarks Captain Stuart, whose account of this
great engineering operation we follow, “that there was apparent danger
in the undertaking, for the weight of the mass to be removed was
estimated at two million tons, and the quantity[Pg 19] of powder used was
more than eight tons, or eighteen thousand pounds. The quantity used in
blowing up the fortifications of Bhurtpore was twelve thousand pounds,
and this is said to have been the greatest explosion that had ever
previously taken place for any single specific object.”
The front of the projection was about one hundred yards wide; this
front was pierced with a tunnel about six feet in height, and three
in breadth; three shafts, equidistant from each other, and from the
entrances to the tunnel, were sunk to the depth of seventeen feet, and
galleries were run, one from each shaft, parallel with each other, and
at right angles with the line of the tunnel. These galleries varied
in length, the longest having been twenty-six feet, and the shortest
twelve feet, and at their extremities chambers were excavated in a
direction parallel with the tunnel. This description will be the better
understood by reference to the following figure.
1. The tunnel. 2. The
shafts. 3. The galleries. 4. The chambers.
In the chambers, the powder was deposited in three nearly equal
quantities; it was done up in fifty-pound bags, and the proportion
in each chamber was contained in a wooden case, nearly as large as
the chamber itself. Ignition was communicated by means of a voltaic
battery; the conducting wires, one thousand feet in length, were
passed over the cliff, one to each chamber, and the electricity was
communicated in a shed built for the purpose on the top of the cliff,
about fifty yards from the edge. The explosion was conducted by
Lieutenant Hutchinson, R.E., who was engaged with General Pasley in
blowing up the wreck of the Royal George. The time appointed for the
explosion to take place, was two o’clock P.M., 26th January,
1843, the tide being then at its lowest ebb. The arrangements, to
preserve order and[Pg 20] prevent danger, were good. A space was kept clear
by a cordon of artillery, and the following programme was issued:—
“Signals, January 26, 1843.
“1st. Fifteen minutes before firing, all the signal flags will be
hoisted.
“2nd. Five minutes before firing, one gun will be fired, and all the
flags will be hauled down.
“3rd. One minute before firing, two guns will be fired, and all the
flags (except that on the point which is to be blasted) will be
hoisted up again.”
These signals were given exactly at the specified times, and when the
expected moment arrived, a deep subterranean sound was heard, a violent
commotion was seen at the base of the cliff, and the whole mass slid
majestically down, forming an immense débris at the bottom.
Tremendous cheers followed the blast, and a royal salute was fired.
The remarks of different intelligent observers, as to the effects of
this explosion, would of course differ according to their position with
respect to the scene of explosion. One observer states that “the earth
trembled to the distance of half a mile; a stifled report, not loud,
but deep, was heard; the base of the cliff, extending on either
hand to upwards of five hundred feet, was shot as from a cannon, from
under the superincumbent mass of chalk seaward; and in a few seconds
not less than a million tons of chalk were dislodged by the shock, and
settled gently down into the sea below.”
But the most eminent observer who has described the effects of
this explosion is Sir John Herschel, from whose letter to the
we gather the following particulars. His position was
on the summit of the cliff, next adjoining the scene of operations, to
the southward, the nearest point to which access was permitted.
Sir John Herschel was particularly struck with “the singular and almost
total absence of all those tumultuous and noisy manifestations of
power, which might naturally be expected to accompany the explosion
of so enormous a quantity (19,000) of gunpowder.” He describes
the noise which accompanied the immediate explosion as “a low murmur,
lasting hardly more than half a second, and so faint, that had a
companion at my elbow been speaking in an ordinary tone of voice, I
doubt not it would have passed unheeded.”
The fall of the cliff, the ruins of which extended over no less
than eighteen acres of the beach, to an average depth of fourteen
feet, was not accompanied with any considerable[Pg 21] noise. “The entire
absence of smoke was another and not less remarkable feature of the
phenomenon. Much dust, indeed, curled out at the borders of the vast
rolling and undulating mass, which spread itself like a semi-fluid
body, thinning out in its progress; but this subsided instantly; and
of true smoke there was absolutely not a vestige. Every part of the
surface was immediately and clearly seen—the prostrate flagstaff
(speedily re-erected in the place of its fall)—the broken turf,
which a few seconds before had been quietly growing at the summit of
the cliff—and every other detail of that extensive field of ruin,
were seen immediately in all their distinctness. Full in the midst of
what appeared the highest part of the expanding mass, while yet in
rapid motion, my attention was attracted by a tumultuous and somewhat
upward-swelling motion of the earth, whence I fully expected to see
burst forth a volume of pitchy smoke, and from which my present
impression is, that gas, purified from carbonaceous matter in passing
through innumerable fissures of cold and damp material, was still in
progress of escape; but whether so or not, the remark made at the
moment is sufficient to prove the absence of any impediment to distinct
vision.”
The amount of tremor experienced by Sir John Herschel at the point
where he was standing was so slight, that he thinks he has felt
it surpassed by a heavy waggon passing along a paved street. “The
impression, slight as it was, was single and brief, and must have
originated with the first shock of the powder, and not from the
subsequent and prolonged rush of the ruins.” We have already noticed
the remark of one observer, that “the earth trembled to the distance of
half a mile;” but this seems to be a mistake; the writer fancied that
it must have been so, and that he should be suspected if he were to
state it otherwise. It is to be regretted that people do not endeavour
to describe what they see and hear, without the embellishment of the
imagination.
This grand experiment was no less grand from the absence of noise,
smoke, earthquake, and fragments hurled to vast distances through
the air. “I have not heard of a single scattered fragment flying out
as a projectile in any direction”—continues Sir John Herschel—“and
altogether the whole phenomenon was totally unlike anything which,
according to ordinary ideas, could have been supposed to arise from the
action of gunpowder. Strange as it may seem, this contrast between the
actual and the expected effects, gave to the whole scene a character
rather of sublime composure than of headlong violence—of graceful ease
than of struggling effort. How quietly, in short, the gigantic power
employed performed[Pg 22] its work, may be gathered from the fact, that the
operators themselves who discharged the batteries were not aware that
they had taken effect, but thought the whole affair a failure, until
reassured by the shout which hailed its success.”
Sawing the Stones for the Mason.
Whatever may be the purpose to which the stone is to be applied, the
larger blocks obtained from the quarry must be cut into smaller and
more manageable pieces; this is done by sawing. The saw used is
a long blade of steel without teeth, fixed in a heavy wooden frame,
similar in principle to that which holds the finer spring-saws employed
by cabinet-makers. The stone-saw, from its great size, however,
requires a more powerful contrivance for drawing it to the proper
degree of tension: this consists of a long screw-bolt fixed to a piece
of chain, which hooks over one of the upright arms of the frame; a
similar chain from the other carries a swivel-joint with a screw-nut
to receive the screw: by turning the swivel by a lever, the nut on the
screw draws up or tightens the chains, and that draws the blade tight,
which is contained between the other ends of the arms.
These huge saws are worked by one or two men, who, in London
stone-yards, sit in watch-boxes, in order to be sheltered from the sun
and rain. Barrels filled with water, which is allowed to drop out at a
tap, are mounted on the block of stone, so that the water may drip into
the cut and facilitate the motion of the saw by removing some of the
friction, as well as prevent it becoming hot, and so losing its temper
by the same cause.
In some large establishments, the sawing is effected by machinery. The
block is fixed in a proper position, and a group of saws brought to act
on it. These saws are all arranged parallel, according to the thickness
of the pieces into which the stone is to be cut; and a steam-engine
being brought to bear on the whole group, the cutting is effected with
great rapidity.
The Processes of Stone-Masonry.
When the stone is sawed to the proper size, the surfaces which are
exposed to view, have to be made smooth and even. The tools used by the
mason for this purpose consist of iron chisels of different widths,
and principally of a sharp-pointed one called a pointer; these
chisels are struck with a mallet made of a conical-formed lump of hard
wood, fixed to a short handle.
[Pg 23]
Stone-Sawyer.
[Pg 24]
The pointer is used for chipping off the principal roughnesses
on the face and edges, and for working the whole face over to bring it
level, the workman trying his work by applying a straight-edge
occasionally to it. When the front and edges are made true, the
face is sometimes tooled over, so as to leave regular furrows in
it, according to certain forms, by which the different kinds of work
are distinguished. But this practice is going out of use, now that soft
free-stone is so much employed in building. In old edifices, such as
Paul’s, Whitehall, &c., &c., the stone will be found to be wrought
on its face in the manner alluded to.
Stones in buildings are not only fixed with mortar, as bricks are, but
are further secured in their places by being clamped together with iron
clamps. These are short iron bars, from seven to twelve inches long,
one and a half wide, and half an inch thick, according to the size of
the stone; the ends of the clamps being turned down a little, to afford
a better hold. A channel is cut in the two contiguous stones deep
enough for the clamp to lie in, and the ends of the channel are sunk
deeper, to receive the turned-down ends of the clamp; when this is put
into the channel, molten lead is poured in to fill up the interstices,
to keep the clamp in its place, and to prevent it from rusting.
From the expense of carrying and working stone, the walls of buildings
at a distance from a quarry, such for example as those in London, are
seldom now built of solid stone, but a facing of this material is
applied only on the external surface of the wall, which is built of
brick. This kind of work is called ashler work, and both the
brick and stone-work must be executed with considerable care, to enable
a wall composed of two materials to preserve its perpendicularity;
it being obvious, that if the brick part yielded to the weight, it
must, from its construction, do so more than the stone facing, and,
therefore, the wall would bend inwards and become crippled.
The width of the courses of ashlers must, therefore, be made equal
exactly to a certain number of courses of bricks with the intervening
mortar, and the brick-work must be executed with such care, that this
number of courses may be everywhere of the same width in the whole
height of the wall. In every course of ashler there must be solid
stones laid quite, or nearly quite, across the width of the wall to
form a bond to the stone facing, and all the stones of the
ashler must be fixed with iron cramps to one another and to these
bond-stones. But, however carefully a faced wall may be executed, it
is never so firm or durable as one built entirely of either material;
indeed, if well executed, of good[Pg 25] materials, and of competent
thickness in proportion to its height, a brick wall is the most
durable, light, and efficient structure that can be erected.
When stone is to be cut into cornices, mouldings, &c., the blocks
having been sawed, the ends, top and bottom, are worked very true and
parallel, or perpendicular to each other, and one edge or arris
cut to a perfectly straight line; a thin wooden mould of the section
of the cornice is then applied to each end, and the profile of the
mouldings marked out on the stone. The workman being guided by this
figure, cuts away the stone down to the general surface of the
mouldings, and then proceeds to get the flat fillets of the mouldings
perfectly straight and true by the rule; these again guide him in
working the curved mouldings, such as ovolos, cavettos,
cyma rectas, and ogees; when these are cut nearly to
their profile, and perfectly straight on the bed line, they are
finished off by being rubbed down smooth by thin long straight-edges of
stone.
Foliage and carved work is executed by a better kind of workman,
possessing some of the taste of an artist, and he works on the same
general principles as a sculptor when executing a statue; it would be
foreign to our present object, therefore, to dwell on this branch of
the mason’s art.
It often, or even most commonly occurs, that the distance between
two columns of a portico, is of greater length than a stone can be
obtained, and if the architrave, or that part of the entablature
immediately over the capitals of the columns, be looked at attentively,
a stone will be perceived between the columns apparently unsupported,
for neither end rests on the column, and the joints of those ends are
upright, not presenting any character of a voussoir-stone or arch. The
contrivance by which such an architrave stone is supported deserves to
be described.
The stone in question has a projecting part, wrought at each end, of
the form shown in the annexed figure; this projection is received into
a corresponding cavity, cut in the end of the stone supported by the
column, and the joint is thus really an arched or wedge-shaped one,
though the bevel[Pg 26] line is concealed, and the two stones, when put
together, present only a vertical joint.
The mason uses squares, levels, plumb-lines, and
straight-edges to set out his work, and trowels and mortar to
set the stones with; but the latter is rather used to make the joints
water-tight than to keep the stones together, this being effected by
their weight or by iron clamping. Formerly the mason required far
more accurate and extensive knowledge of geometry than is possessed
by persons of the trade at present; this was when he was called on
to construct groined and vaulted roofs, enriched with carved work
and pendent corbels, where the nicest workmanship was required, to
ensure the stability of the light and graceful columns and vaulting
of a Gothic cathedral. It was this possession of superior skill and
knowledge that caused the establishment of the Society of Freemasons,
which dates its rise from the tenth or eleventh century.
Marble, from its costliness, and the difficulty of working it, is
seldom, if ever, used in solid pieces in buildings; thin facings of
it are set upon stone backings, much as rare woods are used in
veneering by the cabinet-maker. The marble is sawn into thin
slabs, like other stone, and the face is polished by rubbing on it the
surface of another piece, fine sand, mixed up with water, being used to
cause abrasion.
Various contrivances are resorted to for cutting marble, and
building-stones generally, into curved forms. In some cases a
lever is made to work at one end on a pivot, while at the other end
is attached a curved piece of sheet-iron, which passing backwards and
forwards over the stone, cuts it in a circular form. In other cases
a cylinder of sheet-iron is formed; and this being allowed to fall
vertically on the surface of the stone, and rotated rapidly, cuts out
a piece of stone of the diameter of the cylinder. Sometimes, when a
large circular piece of stone is required, a kind of wheel is employed,
furnished on its under surface with four curved cutting-irons,
and these cutters, when the wheel revolves, cut the stone. By a
modification of the arrangements, an oval instead of a circular curve
may be given to the piece of stone.
[Pg 27]
Chapter II.
ON THE DURABILITY OF STONE BUILDINGS.
“Everything belonging to the earth, whether in its primitive state,
or modified by human hands, is submitted to certain and innumerable
laws of destruction, as permanent and universal as those which produce
the planetary motions. The operations of nature, when slow, are no
less sure; however man may for a time usurp dominion over her, she is
certain of recovering her empire. He converts her rocks, her stones,
her trees, into forms of palaces, houses, and ships; he employs the
metals found in the bosom of the earth as instruments of power, and the
sands and clays which constitute its surface as ornaments and resources
of luxury; he imprisons air by water, and tortures water by fire to
change, to modify, or destroy the natural forms of things. But in some
lustrums his works begin to change, and in a few centuries they decay
and are in ruins; and his mighty temples, framed, as it were, for
divine purposes, and his bridges formed of granite, and ribbed with
iron, and his walls for defence, and the splendid monuments by which he
has endeavoured to give eternity even to its perishable remains, are
gradually destroyed; and these structures which have resisted the waves
of the ocean, the tempest of the sky, and the stroke of the lightning,
shall yield to the operation of the dews of heaven, of frost, rain,
vapour, and imperceptible atmospheric influences; and as the worm
devours the lineaments of his mortal beauty, so the lichens and the
moss, and the most insignificant plants, shall feed upon his columns
and his pyramids, and the most humble and insignificant insect shall
undermine and sap the foundations of his colossal works, and make their
habitations amongst the ruins of his palaces, and the falling seats of
his earthly glory.”[1]
Although it is true that all human works must decay, yet it is a point
of great importance to ourselves and our successors whether that decay
be slow or speedy. The causes enumerated in the above eloquent passage,
though sure, are exceedingly slow in their action, and provided the
building materials have been selected with reference as well to their
durability as to their beauty, the resulting structure may defy the
corroding tooth of time for many ages, and we may thus transmit [Pg 28] to a long posterity, lasting memorials of our wisdom and science, as
well as of our piety. Modern science has, to a very great extent,
enabled the architect and builder to determine beforehand what is the
durability of any given stone; and it is with great pleasure that we
now notice the extensive inquiry made at the suggestion of Barry,
the architect of the new Houses of Parliament, under the Commission
issued by Her Majesty’s Government, to investigate the qualities of
stone in various parts of the kingdom, in order to select that which
should best ensure perpetuity to this grand national monument. This
commission, consisting of Barry, Sir H. T. De la Beche, W.
Smith, and C. H. Smith, visited one hundred and five quarries, and
examined one hundred and seventy-five edifices; and their collected
specimens were then submitted to tests, both mechanical and chemical,
by Professors Daniell and Wheatstone, of King’s College, London. In
order to leave a permanent record of their labours, the Commissioners
published a Report, and deposited in the Museum of Economic Geology, a
variety of specimens of the stones which they had collected. From this
Report, we select such details as are calculated to serve the purposes
of popular instruction. The Commissioners did not consider it necessary
to extend their inquiries to granites, porphyries, and other stones of
similar character, on account of the enormous expense of converting
them to building purposes in decorated edifices, and from a conviction
that an equally durable, and in other respects more eligible material,
could be obtained for the object in view from among the limestones or
sandstones of the kingdom.
The Commissioners soon had striking proofs of the necessity and
importance of this inquiry in the lamentable effects of decomposition
observable in the greater part of the limestone employed at Oxford; in
the magnesian limestones of the Minster, churches, and other public
edifices at York; and in the sandstones of which the churches and
other public buildings at Derby and Newcastle are constructed; and
numerous other examples. The unequal state of preservation of many
buildings, often produced by the varied quality of the stone employed
in them, although it may have been taken from the same quarry, showed
the propriety of a minute examination of the quarries themselves, in
order to gain a proper knowledge of the particular beds from whence the
different varieties have been obtained. An inspection of quarries was
also desirable for the purpose of ascertaining their power of supply,
and other important matters; for it frequently happens, that the
best stone in quarries is often neglected, or only partially worked,
in consequence of the cost of laying bare, and[Pg 29] removing those beds
with which it may be associated; whence it happens, that the inferior
material is in such cases supplied.
Stone buildings decay more rapidly in towns than in the open country,
where dense smoke, fogs, and vapours, which act injuriously on
buildings, do not exist. There is also another curious cause which
contributes to the durability of stone buildings situated in the
country. In the course of time, the stone becomes covered with minute
lichens, which, though in themselves decomposing agents, act with
extreme slowness, and when once firmly established over the entire
surface of the stone, seem to exercise a protective influence, by
defending the surface from the more violent destructive agents;
whereas, in populous smoky towns, these lichens are prevented from
forming, and thus the stone is exposed to severer trials than stone of
the same kind situated in the country.
As a remarkable illustration of the difference in the degree of
durability in the same material, subjected to the effects of the air
in town and country, the appearance is noticed of several frusta of
columns, and other blocks of stone, that were quarried at the time
of the erection of Paul’s Cathedral, London, and which are now
lying in the Isle of Portland, near the quarries from whence they were
obtained. These blocks are invariably found to be covered with lichens,
and, although they have been exposed to all the vicissitudes of a
marine atmosphere for more than one hundred and fifty years, they still
exhibit beneath the lichens their original form, even to the marks of
the chisel employed upon them; whilst the stone which was taken from
the same quarries, (selected no doubt with equal, if not greater care,
than the blocks alluded to,) and placed in the Cathedral itself, is, in
those parts which are exposed to the south and south-west winds, found,
in some instances, to be fast mouldering away.
Colour is more important in the selection of a building-stone to be
situated in a populous and smoky town, than for one to be placed in
the open country, where all edifices become covered with lichens; for,
although in such towns, those fronts which are not exposed to the
prevailing winds and rains, will soon become blackened, the remainder
of the building will constantly exhibit a tint depending upon the
natural colour of the stone.
The chemical action of the atmosphere produces a change in the entire
matter of the limestones, and in the cementing substance of sandstones,
according to the amount of surface exposed to it. The particles of the
stone first loosened by the action of frost are removed by powerful
winds and driving rains. The buildings in this climate were generally
found to suffer the greatest amount of decomposition on their south,[Pg 30]
south-west, and west fronts, arising doubtless from the prevalence of
winds and rains from those quarters.
Those buildings which are highly decorated, such as the churches of
the Norman and pointed styles of architecture, generally afford a more
severe test of the durability of a building-stone, than the more simple
and less decorated castles of the fourteenth and fifteenth centuries;
because, in the former class of buildings, the stone is worked into
more disadvantageous forms than in the latter, as regards exposure to
the effects of the weather. Buildings in a state of ruin, from being
deprived of their ordinary protection of roofing, glazing of windows,
&c., afford an equally severe test of the durability of the stone
employed in them.
The durability of various building-stones in particular localities was
estimated by examining the condition of the neighbouring buildings
constructed of them. Among sandstone buildings was noticed the remains
of Ecclestone Abbey, of the thirteenth century, near Barnard Castle,
constructed of a stone closely resembling that of the Stenton quarry,
in the vicinity, in which the mouldings and other decorations were in
excellent condition. The circular keep of Barnard Castle, apparently
also built of the same material, is in fine preservation. Tintern
Abbey is noticed as a sandstone edifice, that has to a considerable
extent resisted decomposition. Some portions of Whitby Abbey are fast
yielding to the effects of the atmosphere. The older portions of Ripon
Cathedral; Rievaulx Abbey; and the Norman keep of Richmond Castle, in
Yorkshire, are all examples of sandstone buildings, in tolerably fair
preservation.
Of sandstone edifices in an advanced state of decomposition, are
enumerated Durham Cathedral, the churches at Newcastle-upon-Tyne,
Carlisle Cathedral, Kirkstall Abbey, and Fountain’s Abbey. The
sandstone churches of Derby are also extremely decomposed; and the
church of Peter, at Shaftsbury, is in such a state of decay, that
some portions of the building are only prevented from falling by means
of iron ties.
The choir of Southwell Church, of the twelfth century, affords an
instance of the durability of a magnesio-calciferous sandstone after
long exposure to the influences of the atmosphere. The Norman portions
of this church are also constructed of magnesian limestone, similar to
that of Bolsover Moor, and which are throughout in a perfect state, the
mouldings and carved enrichments being as sharp as when first executed.
The following buildings, also of magnesian limestone, are either in
perfect preservation, or exhibit only slight traces of decay: the keep
of Koningsburgh Castle; the[Pg 31] church at Hemingborough, of the fifteenth
century; Tickhill Church, of the same date; Huddlestone Hall, of the
sixteenth century; Roche Abbey, of the thirteenth century.
The magnesian limestone buildings which were found in a more advanced
state of decay, were the churches at York, and a large portion of the
Minster, Howden Church, Doncaster Old Church, and buildings in other
parts of the county, many of which are so much decomposed, that the
mouldings, carvings, &c., are often entirely effaced.
The report speaks in high terms of the preservation of buildings
constructed of oolitic and other limestones; such are Byland Abbey, of
the twelfth century; Sandysfoot Castle, near Weymouth, constructed of
Portland oolite in the time of Henry the Eighth; Bow-and-Arrow Castle,
and the neighbouring ruins of a church of the fourteenth century, in
the island of Portland.
The oolite in the vicinity of Bath does not seem to wear well.
The excellent condition of the parts which remain of Glastonbury Abbey
shows the value of a shelly limestone similar to that of Doulting;
whilst the stone employed in Wells Cathedral, apparently of the same
kind, and not selected with equal care, is in parts decomposed. In
Salisbury Cathedral, built of stone from Chilmark, we have evidence of
the general durability of a siliciferous limestone; for, although the
west front has somewhat yielded to the effects of the atmosphere, the
excellent condition of the building generally is most striking.
The materials employed in the public buildings of Oxford, afford a
marked instance both of decomposition and durability; for whilst a
shelly oolite, similar to that of Taynton, which is employed in the
exposed parts of the more ancient parts of the Cathedral, in Morton
College Chapel, &c., is generally in a good state of preservation, a
calcareous stone from Heddington, employed in nearly all the colleges,
churches, and other public buildings, is in such a deplorable state of
decay as, in some instances, to have caused all traces of architectural
decoration to disappear, and the ashler itself to be, in many places,
deeply disintegrated.
In Spofforth Castle, two materials, a magnesian limestone and a
sandstone, have been employed, the former in the decorated parts, and
the latter for the ashler, and although both have been equally exposed,
the magnesian limestone has remained as perfect in form as when first
employed, while the sandstone has suffered considerably from the
effects of decomposition. In Chepstow Castle a magnesian limestone is
in fine preservation, and a red sandstone rapidly decaying.[Pg 32] A similar
result was observed in Bristol Cathedral, which afforded a curious
instance of the effects of using different materials; for a yellow
limestone and a red sandstone have been indiscriminately employed both
for the plain and the decorated parts of the building; not only is the
appearance unsightly, but the architectural effect of the edifice is
also much impaired by the unequal decomposition of the two materials.
After enumerating these and other examples, the Report gives the
preference to the limestones, on account of their more general
uniformity of tint, their comparatively homogeneous structure, and the
facility and economy of their conversion to building purposes; and, of
this class, preference is given to those which are most crystalline.
Professor Daniell is of opinion that the nearer the magnesian
limestones approach to equivalent proportions of carbonate of lime and
carbonate of magnesia, the more crystalline and better they are in
every respect.
It was considered that this crystalline character, together with
durability, as instanced in Southwell Church, &c.; uniformity in
structure; facility and economy in conversion; and advantage in
colour, were all comprised in the magnesian limestone, or dolomite
of Bolsover[2] Moor and its neighbourhood, and was accordingly
recommended as the most fit and proper material to be employed in the
New Houses of Parliament.[3] This opinion was not arrived at, nor this
recommendation made, until after a very extensive series of experiments
had been completed by Professors Daniell and Wheatstone upon specimens
of the stones of the various quarries visited by the Commissioners.
The specimens, as delivered to these gentlemen, were in the form
of two-inch cubes. These experiments were of a most comprehensive
kind. The composition of the stones was determined by chemical
analysis:—their specific gravities; their weights after having been
perfectly dried by exposure in heated air for several days; then their
weights after having been immersed [Pg 33]in water for several days so as to become saturated; the object
being to ascertain the absorbent powers of the stones, which was
further tested by placing them in water under the exhausted receiver
of an air-pump. The stones were also subjected to the process of
disintegration, invented by M. Brard, the object of which is to
determine, by easy experiments, whether a building-stone will or will
not resist the action of frost. Lastly, the cohesive strength of each
specimen, or its resistance to pressure, was tested by the weight
required to crush it. This weight was furnished by a hydrostatic press,
the pump of which was one inch in diameter: one pound at the end of the
pump lever produced a pressure on the surface of the cube equal to 2·53
cwt., or to 71·06 on the square inch. These trials were made with
caution; the weight on the lever was successively increased by a single
pound; and, in order to ensure a gradual action, a minute was allowed
to elapse previous to the application of each additional weight. It was
noted for each specimen the pressure at which the stone began to crack,
and also the pressure at which it was crushed.
The results of all these experiments (which are stated for each
stone) gave a decided preference to the Bolsover magnesian limestone,
which was noticed as being remarkable for its peculiarly beautiful
crystalline structure, while it was the heaviest and strongest of
all the specimens, and absorbed least water. Its composition was 50
per cent. of carbonate of lime, and 40 of carbonate of magnesia; the
remaining ten parts consisting chiefly of silica and alumina.
An easy Method of determining whether a Stone will resist the Action of
Frost.
In the choice of a stone for building purposes, it is of the utmost
importance to be able to determine, by a few prompt and easy
experiments, whether the proposed stone is capable of resisting the
destructive action of moisture and frost. The means of ascertaining
this were difficult and uncertain, until M. Brard, several years ago,
communicated his method to the Royal Academy of Sciences at Paris.
This learned body having appointed a Committee of their own members to
inquire into the merits of M. Brard’s process, and to make a report
thereon, the united testimony of engineers, architects, masons, and
builders from different parts of France, was received, and proved
so favourable as to its merits and simplicity, that the Committee
recommended the plan to public notice and general adoption. From their
Report we[Pg 34] select a few details, which hitherto, we believe, have not
appeared in English.
When water is converted into ice an increase in bulk suddenly
takes place with such amazing force that it appears to be almost
irresistible. This is the force which cracks our water-bottles and
ewers; splits asunder the trees of our forests; and destroys some of
the stones of our buildings. But the action of frost upon stone is
very gradual; it is confined to the surface, and when we see a layer
of stone separated from the rock or the building, we see the result of
the action of the frost during several successive winters, whereby the
fragment is gradually thrust out of its perpendicular position, and at
length falls. This natural process is repeated in our buildings: we
rarely see squared stones split into large fragments by the action of
frost except there be a cavity of some considerable size, in which a
quantity of water can be collected. The usual action of the frost is at
the surface, which is destroyed by the chipping off of small fragments
in consequence of the adhesion of the materials of the stone being
partially destroyed.
All stones absorb water in greater or less quantities, and there is no
rock that does not contain some humidity. The great difference between
stones which is now to be considered is in their power of resisting
frost. Stones of the same kind, nay, stones from different parts of
the same quarry, are acted upon very differently by frost; for, while
one stone soon begins to show the destructive effects of its action,
another remains uninjured during many centuries. It will, therefore, be
convenient to call those stones, of whatever kind, which withstand the
action of frost, resistant, and those which yield to its action,
non-resistant.
M. Brard’s first idea, in order to test these resistant properties
in building-stones, was, to saturate the stone with water, and then
expose it to cold artificially produced; but this was found to be
impracticable on a large scale, and the freezing mixtures and other
means of producing cold were liable to act chemically upon the stone,
and thus produce other effects than those of cold.
M. Brard was then led to compare water with those numerous solutions of
the chemist, which, under certain modes of treatment, crystallize. The
expansive force of salts in crystallizing is very great, and he saw no
reason why water should not be regarded as a crystalline salt similar
in its nature to those saline bodies which effloresce at the surfaces
of stones, and in time destroy them and even reduce them to powder.
He therefore tried, in a very large number of experiments, the action
upon building-stones of solutions of nitre, of common[Pg 35] salt, of Epsom
salts, of carbonate and sulphate of soda, of alum and of sulphate
of iron, and found that the stones cracked and chipped, and in many
cases behaved precisely in the same way as when under the influence
of freezing water. In the course of these trials, sulphate of soda
(Glauber’s salts) was found to be the most energetic and active, and to
be the best exponent of the action of freezing water.
In order, therefore, to determine promptly if a stone be resistant or
non-resistant, the following process was adopted. A saturated solution
of sulphate of soda was made in cold water; the solution being put into
a convenient vessel, the stone was immersed, and the solution boiled
during half an hour: the stone was then taken out, and placed in a
plate containing a little of the solution. It was then left in a cool
apartment, in order to facilitate the efflorescence of the salt with
which the stone was now impregnated. At the end of about twenty-four
hours the stone was covered with a snowy efflorescence, and the liquid
had disappeared either by evaporation or by absorption. The stone was
then sprinkled gently with cold water until all the saline particles
disappeared from the surface. After this first washing the surfaces
of the stone were covered with detached grains, scales, and angular
fragments, and the stone being one that was easily attacked by frost,
the splitting of the surfaces was very marked. But the experiment was
not yet terminated: the efflorescence was allowed to form, and the
washing was repeated many times during five or six days, at the end of
which time the bad qualities of the stone became fully established. The
stone was finally washed in pure water; all the detached parts were
collected, and by these the ultimate action of the frost upon the stone
was estimated.
The behaviour of various non-resistant stones under this process was
remarkable. Some were found to have deteriorated in the course of
the third day; others to have entirely fallen to pieces; those of
which the power of resistance was somewhat greater, held out till the
fifth or sixth day; but few stones, except the hard granites, compact
limestones, and white marbles, were able to stand the trial during
thirty consecutive days. For all useful purposes, however, eight days
suffice to test the resistant qualities of any building-stone.
The explanation of this process is very easy. The boiling solution
dilates the stone and penetrates it to a certain depth, nearly in
the same way that rain water by long-continued action introduces
itself into stones exposed to the severity of our changeable climate.
Pure water when frozen occupies a greater bulk than when fluid, and
the pores or cellules of the[Pg 36] stone not being able to accommodate
themselves to the increased bulk of the water, great pressure is
exerted between and among them, whereby a portion of the water is
driven to the surface, and in doing so rends and detaches small
portions of the stone. The same action takes place with the saline
solution; it is introduced into the stone in a fluid state, from which
passing into the solid it occupies a greater bulk, and a portion of
it appears at the surface. The repeated washings have no other object
than to allow the salt to exert its greatest amount of destructive
action upon the stone. There is a striking analogy between the effect
of congealed water and that of the efflorescence of salts, in the
disintegration of non-resistant stones; namely, that pure water acts on
the stones destructively only in a state of snowy efflorescence, which
evidently proceeds from the interior to the exterior like the saline
efflorescence; whilst water at the surface of the stones may freeze
into hard ice without injuring them, just in the same way as salts,
which may crystallize upon stones without exerting any injurious action.
The experience of several engineers, extending as it does over several
years, fully proves, of a large variety of stones whose qualities
were well known, that the action of M. Brard’s process and that of
long-continued frost exactly coincide.
It is not the least interesting part of the inquiry to know that this
process may be applied with perfect success to ascertain the solidity
and resistant power of bricks, tiles, slates, and even mortar. From a
mass of minute detail, we will select a few general results.
During one winter season M. Vicat composed seventy-five varieties of
mortar, the difference between any two consisting in the proportion of
sand and the method of slaking the lime. In the following June these
mortars were exposed to the disintegrating process. Most of them were
attacked in twenty-four hours; almost all of them in forty-eight hours;
and all except two in three days. This gentleman also found that a
mortar made ten years previously, of one hundred parts lime, which had
been left exposed to the air, under cover, during a whole year, and
then mixed up into a paste with fifty parts of common sand, withstood
the trial admirably during seventeen days, while the best stones of
the neighbourhood speedily gave way. In this case the solution was
saturated while hot, which is so powerful in its effects that stones
which have resisted the action of the frost for ages, soon gave way
when exposed to it.
M. Vicat calculates that the effect of the sulphate of soda upon a
non-resistant stone after the second day of trial equals[Pg 37] a force
somewhat greater than that exerted by a temperature of about 21°
Fahrenheit, on a stone saturated with water.
The action of the process upon bricks proved that, whatever their
qualities in other respects, if imperfectly burnt, they are speedily
acted on. The sharp edges of the brick, and then the angles, are first
rounded, and finally the brick is reduced to powder. Such is precisely
the action of frost often repeated. Well-baked bricks, on the contrary,
retain their colour, form, and solidity by this process, as well as
under the influence of frost. Ancient Roman bricks, tiles, and mortar,
and hard well-baked pottery resisted the process perfectly; as did also
white statuary marble of the finest quality, while common white marble
was soon attacked. In Paris, portions of buildings which had been
exposed to the air during twenty years without undergoing the least
alteration, were submitted to this ordeal, and the experiment agreed
with observation. In one extensive series of experiments on stones from
different quarries of France, the action of the salt was continued
for seven days, and the results noted down; it was then continued for
fourteen days, and the results compared with the preceding ones; which
only served to confirm the judgment first given, for those stones which
were noted as of bad quality crumbled to dust or split into fragments,
while those noted for their good qualities had experienced no sensible
alteration.
One of the great advantages of this process is the power it gives to
the architect of choosing a hard, durable stone for those parts of the
building most exposed to the action of the weather, when the funds
are insufficient to admit of the whole building being so constructed.
Thus the cornices, the columns, and their capitals, are struck in all
directions by rain, and hail, and damp air, and are consequently far
more exposed to their destructive action than the flat surface of a
wall, which offers but one plane to the air.
In the course of this inquiry a very curious case arose. During the
erection of a church in Paris, the architect required a good durable
stone for the Corinthian capitals; and many circumstances disposed him
to select it from the neighbouring quarry of the Abbaye du Val. But, on
seeking the opinion of two brother architects, he was surprised to find
their estimations of the stone to be totally at variance, for while one
declared that he had employed it with the greatest success, another
said that he had seen it yield speedily to the effects of frost. On
visiting the quarry it was found that two beds of stone were being
worked, an upper and a lower bed; specimens of the stone were taken
from each, and on submitting them to a hot saturated solution, it was[Pg 38]
ascertained almost immediately that the upper layer furnished excellent
stone, while the lower one supplied that of which the architect had
so much reason to complain. But it is remarkable that the stones from
the two beds had precisely the same appearance in grain, colour, and
texture; so much so, that when brought into the mason’s yard it was
impossible by ordinary tests to distinguish the good from the bad stone.
At the conclusion of the inquiry of the Committee, the Royal Academy
of Sciences proved the high estimation in which they held this
contribution of science to the useful arts, by directing to be
published the following practical directions for repeating the process,
for the use of architects, builders, master masons, land proprietors,
and all persons engaged in building.
- The specimens of stone are to be chosen from those parts of the quarry, where from certain observed differences in the colour, grain, and general appearance of the stone, its quality is doubtful.
- The specimens are to be formed into two-inch cubes, carefully cut, so that the edges may be sharp.
- Each stone is to be marked or numbered with Indian ink or scratched with a steel point; and corresponding with such mark or number a written account is to be kept as to the situation of the quarry, the exact spot whence the stone was detached, and other notes and information relating to the specimen.
- Continue to add a quantity of sulphate of soda to rain or distilled water, until it will dissolve no more. You may be quite sure that the solution is saturated, if, after repeatedly stirring it, a little of the salt remains undissolved at the bottom of the vessel an hour or two after it has been put in.
- This solution may be heated in almost any kind of vessel usually put on the fire, but perhaps an earthen pipkin may be most convenient. When the solution boils, put in the specimens of stone, one by one, so that all may be completely sunk in it.
- Continue the boiling for thirty minutes. Be careful in observing this direction.
- Take out the cubes one at a time, and hang them up by threads in such a way that they may touch nothing. Place under each specimen a vessel containing a portion of the liquid in which the stones were boiled, having first strained it to remove all dirt, dust, &c.
- If the weather be not very damp or cold the surfaces of each stone will, in the course of twenty-four hours, become[Pg 39] covered with little white saline needles. Plunge each stone into the vessel below it, so as to wash off these little crystals, and repeat this two or three times a day.
- If the stone be one that will resist the action of frost, the crystals will abstract nothing from the stone, and there will be found at the bottom of the vessel neither grains, nor scales, nor fragments of stone. Be careful, in dipping the stone, not to displace the vessel.
If, on the contrary, the stone is one that will not resist the action of frost, this will be discovered as soon as the salt appears on the surface, for the salt will chip off little particles of the stone, which will be found in the vessel beneath; the cube will soon lose its sharp edges and angles; and by about the fifth day from the first appearance of the salt, the experiment may be considered at an end.
As soon as the salt begins to appear at the surface its deposit is assisted by dipping the stone five or six times a day into the solution.
- In order to compare the resisting powers of two stones which are
acted upon by the frost in different degrees, all that is necessary is,
to collect all the fragments detached from the six faces of the cube,
dry them and weigh them, and the greatest weight will indicate the
stone of least resistance to the frost. Thus, if a cube of twenty-four
inches of surface loses 180 grains, and a similar cube only 90 grains,
the latter is evidently better adapted than the former to the purposes
of building.
FOOTNOTES:
[1] Sir Humphry Davy.
[2] Bolsover is a small market town in Derbyshire, on the borders of the county of Nottingham, and about 145 miles from London.
[3] The various quarries visited by the commissioners are noticed in the fullest and fairest manner. They have stated for each quarry its name and situation; the names and addresses of the freeholder, of his agent, and of the quarryman; the name of the stone; its composition; colour; weight per cubic foot; entire depth of workable stone; description of the beds; size of blocks that can be procured; prices, per cubic foot, of block stone at the quarry; description and cost of carriage to London; cost, per cubic foot, of the stone delivered in London; cost, per foot of surface, of plain rubbed work, as compared with Portland stone; and, finally, where known or reported to have been employed in building. [Pg 40]
Chapter III.
THE WALLS. BRICKS AND BRICK-WORK.
We now come to that material which is, in England, a more important agent than stone in the construction of dwelling-houses; namely, bricks made from clay. There were three millions and a half of houses in Great Britain in the year 1841; and there can be no doubt that of this number those which were built of brick constituted a vast majority. It is only in a few particular districts that stone is a more available material for houses than bricks. In other countries, too, as well as our own, the arts of brick-making and bricklaying are carried on more extensively than the operations of the stone-mason.
Bricks and Brick-work in Early Times.
It has been observed that “the art of making bricks is so simple, that
it must have been practised in the earliest ages of the world; probably
before mankind had discovered the method of fashioning stones to suit
the purposes of building.” It is stated in the Book of Genesis that
burnt bricks were employed in the construction of the Tower of Babel.
Now, as this structure appears to have been raised about four hundred
years after the Deluge, it is scarcely an exaggeration to say that the
art of making bricks was invented almost as soon as men began to build.
Bricks seem to have been in common use in Egypt while the Israelites
were in subjection to that nation; for the task assigned them was the
making of brick, and we are informed in the Book of Exodus, that the
Israelites built two Egyptian cities. No particulars are given in
Scripture of the method of making bricks; but as straw was one of the
ingredients, and as very little rain falls in Egypt, it is probable
that their bricks were not burned, but merely baked by the heat of the
sun. The same mode of baking bricks seems still to be practised in the
East. The ruins of the tower near Bagdad are formed of unburnt bricks.
The art of brick-making was carried to considerable perfection among
the Greeks. Pliny states that they made use of bricks of three sizes,
distinguished by the following names: , or six inches
long; , or twelve inches long; and ,
or fifteen inches long. That the Romans excelled in the art of making
bricks there is the amplest evidence, since brick structures raised at
Rome seventeen hundred years ago, still remain nearly as entire as when
first built.
[Pg 41]
A remarkable kind of floating brick, used by the ancients, has
been made the subject of investigation in modern times, with a view to
the suggestion of improvements in the making of bricks for particular
purposes. Pliny states that at various places in Spain, in Asia Minor,
and elsewhere, bricks were made which, besides possessing considerable
strength and a remarkable power of enduring heat, were yet of such
small specific gravity, that they floated on the surface of water. Like
many of the arts of the ancients, the method of making these bricks, as
well as the material of which they were made, were forgotten for many
ages. About the year 1790, however, an Italian, named Fabbroni, turned
his attention to the subject, and after various experiments on minerals
of small specific gravity, he came to the conclusion that these
bricks must have been composed of a substance called “mountain-meal;”
or, at least, he found that he could make of this substance bricks
which appeared to agree in every respect with those described by the
ancients. This mountain-meal is an earth composed of flint, magnesia,
clay, lime, iron, and water, in certain definite proportions. The
bricks which Fabbroni formed of this material had the property of
floating in water; they could not be fused by any ordinary degree of
heat; and so low was their conducting power, that while one end of the
brick was red-hot, the other could be held in the hand without the
smallest inconvenience. It has been supposed that a peculiar kind of
earth, found in some parts of Cornwall is the same as that with which
Fabbroni experimented on in Italy, and that both are analogous to the
kind of which the ancients made their floating bricks. Proceeding on
this supposition, it has been proposed to make such bricks for the
construction of floating houses upon ornamental waters. At
present such structures can be made only of timber; and, however the
owner may decorate them, they have always a flimsy and unsubstantial
appearance, and they are soon injured by the weather. If, however, a
platform of good timber were employed as the base of the whole, and the
weight so contrived as to keep this platform constantly under water,
it would last a long time. The upper part of the structure formed of
the floating bricks, might have all the appearance, and, indeed, all
the stability of a brick house upon land; for this description of brick
resists the influence of the atmosphere as well as the action of fire;
and although it is not absolutely so strong as the heavy brick in
common use, it is far more so in proportion to its specific gravity. We
do not know whether these conjectures have yet been put to the test.
That the early inhabitants of many countries in the eastern[Pg 42] and
central parts of Asia were acquainted with the use of bricks in
building, we have abundant proof from the descriptions of intelligent
travellers; and there are even grounds for attributing to them a very
high degree of mechanical skill both in the making of the bricks and
the formation of brick walls. Kennedy, in his , says:—“Nothing I have ever seen has at all equalled the
perfection of the early brick-making, which is shown in the bricks
to be found in these ruins [ancient tombs near Tatta]: the most
beautifully chiselled stone could not surpass the sharpness of edge,
and angle, and accuracy of form; whilst the substance was so perfectly
homogeneous and skilfully burned, that each brick had a metallic ring,
and fractured with a clear surface, like breaking freestone. I will not
question the possibility of manufacturing such bricks in England, but I
much doubt whether such perfect work has ever been attempted.”
Making Bricks by Hand.
In the mechanical arrangements for making bricks two very different
systems are adopted; the one handicraft, and the other by machinery.
The former has always been and still is far more extensively adopted
than the latter.
In the selection of materials for brick-making, a brown loamy clay,
that is, clay which contains a small quantity of calcareous matter, is
considered best for ordinary bricks, but the ingredients vary according
to the purposes for which the brick is required; and every one must
have remarked the difference in colour between the light yellow marl
stocks, as they are called, employed in the facing of houses of
the better kind, and the dark red brick used in Lancashire and other
northern counties. The colour also varies with the proportion of ashes
or sand employed in the mixture, and with the degree of heat they are
subjected to in drying. The general process is, however, much the same
everywhere; and we shall describe that used in England, where bricks
are always burnt.
The proper kind of clay being found, the top vegetable mould is
removed, and the earth dug and turned over to expose it as much as
possible to atmospheric action, and for this purpose it is left for
the winter. In spring, a quantity of fine ashes, varying in proportion
to the clay from one-fourth to a fifth, according to the stiffness of
the latter, is added by degrees, and well incorporated by digging and
raking, water being poured on to render the mass soft. When the union
is effected, the clay is carried in barrows[Pg 43] to a rude mill, erected
near the shed, in which the brickmaker works.
This mill consists usually of a vat, or circular vessel, fixed on a
timber frame; an upright iron axle is placed in the centre of the vat,
and carries some iron plates, or rakes with teeth, to stir up the soft
clay when placed in the mill: this axle is turned round by a horse
harnessed to a horizontal shaft which proceeds from the axle. The
clay being put into the vat, the rakes or knives complete the
incorporation of the ashes, and thoroughly temper the whole mass, which
is gradually squeezed out through a hole in the bottom of the vat.
A better kind of mill is used in tempering the material for the better
bricks; it only differs, however, in being larger. An iron harrow
loaded with weights is dragged round in a circular pit lined with
brick-work. The clay in this case is diluted with water sufficiently
to allow of the stones sinking to the bottom; and the fluid is drawn
off into pits, where it is left to settle and thicken, to the proper
consistence.
The prepared clay is first separated into masses, each large enough to
make a brick, by the feeder, or assistant, who sands the pieces
ready for the moulder; the mould is an open rectangular
box, the four sides of which are made to separate from the bottom, to
allow of the brick being turned out. The bottom is now made with a lump
raised on it, by which a slight depression is formed on one side of the
brick, to admit a mass of the mortar being received and detained in it
when the wall is built.
The moulder takes the piece of clay prepared for him, and dashing each
into the mould so as to cause it to fill it, removes the superfluous
quantity by means of a flat piece of wood which he draws across the
open side of the mould; this strike is kept in a bowl of water
to wet it, and prevent the adhesion to it of the clay. The man then
lifts off the sides of the mould, and deposits the brick on a flat
pallet-board, and this is removed by a boy who ranges the bricks
on a lattice frame set sloping on the barrow in which they are to be
taken to the field to dry; fine sand is strewed on the frame and over
the bricks, to prevent their adhering together.
The bricks are taken to the field, and piled in long lines called
hacks. This is a nice operation, as the soft bricks, if
handled roughly, would become twisted, and rendered useless; the
bottom course of bricks is raised a few inches to keep it from the
wet; and the ground is prepared to receive them by being covered with
dry brick-rubbish or ashes, and[Pg 44] raked smooth. The bricks are set
alternately in rows lengthwise and crosswise, with intervals between
them of an inch or more, to allow a thorough circulation of air: the
hack, when raised about a yard high, is covered over with straw to
throw off the rain.
If the weather be favourable, ten or twelve days are enough to dry the
bricks in the hacks sufficiently to prepare them for burning, but they
should be thoroughly dry, or the subsequent process will fail.
Ordinary bricks for building are burnt in clamps, which are
large oblong masses, built up of the unburnt bricks, laid regularly
in layers, with large flues or passages at intervals, in which ashes,
cinders, coal, and brush-wood are laid; layers of ashes are strewed
over those of the bricks. The object is, that the fire, when the fuel
is ignited, may penetrate every part of the mass, and bake every
brick equally; even the ashes mixed up in the clay are intended to be
partly burnt by the heat. In clamps well constructed the outside is
coated with clay or plaster to keep in the heat, and when the fuel is
thoroughly lighted, the external apertures should be stopped up.
The clamp when completed contains from 100,000 to 500,000 bricks. The
fire will continue burning about three weeks, if the pile has been well
constructed: when all smoke ceases to rise, the clamp is taken down
when cold, and the bricks sorted; for, even with the utmost care, it
must happen that the bricks are not all equally burnt. The best are
those in the centre. The under-burnt ones are reserved to be rebuilt
into a new clamp for further baking, and those which are over-done, and
have run together by partial vitrification, are sold at a cheap rate
for making foundations for houses, roads, &c.
The better or peculiar kinds of bricks, as well as tiles of all kinds,
are burnt in kilns instead of clamps. These kilns, though of a peculiar
form, according to the purpose to which they are applied, yet do not
differ in principle from the lime-kiln, &c. In the kiln, the fire is
not intermixed with the bricks, but is applied beneath; nor are ashes
mingled with the clay of which kiln-burnt bricks are made.
As the general principles are the same in making tiles and bricks,
we shall class all these coarse pottery-works together here, in an
enumeration of the most important kinds used in Britain.
Place-Bricks are the worst of the clamp-burnt stocks, and are
used for common walls, and the poorest kinds of work; they are soft and
unequally burnt; they sell from 20 to 30 a thousand.
Stock-Bricks are those from the centre of the clamp, and are
regularly burnt, of an equally hard texture, and even colour;[Pg 45] they are
used for good work of all kinds; the price varies from 30 to
40 a thousand.
Malm-Stocks are clamp bricks, but made with more care from
clay to which ooze, chalk, or marl is added; and the whole carefully
tempered; they are of a fine clear yellow colour, and are used for
facing the walls of good houses, and for making arches over doors and
windows in general, where they are to be seen. The softest kind are
called cutters, from their admitting of being cut, or trimmed,
with the trowel with nicety. The prices of these bricks vary greatly.
Fire-Bricks are made of a peculiar kind of clay, found in
perfection at Windsor, Stourbridge, and parts of Wales, whence the
varieties derive their names. They are formed from the clay without any
admixture of ashes, and are always kiln-burnt. They vary in size, and
are used for building furnaces, ovens, boilers, &c.
Pan-Tiles are tiles, the cross section of which may be
represented thus.
They are used for
roofing outhouses, stables, &c., the edges of one row overlapping those
of another next it, and they are always set in mortar: the end of the
tile is formed with a projecting knob or fillet, by means of which the
tile is hooked on to the batten or lath. These tiles are much larger
than the Plain-Tiles, which are used in roofing dwellings, &c.;
they are flat, as the name indicates, and are fixed to the laths of the
roof by wooden pegs, two holes being left in the tile for that purpose.
Foot and ten-inch tiles are thick square tiles of those dimensions,
used for paving, hearths, &c., or for coping walls. All tiles are burnt
in a kiln.
Bricks made in Great Britain are charged with a duty, and as it
constitutes an important item in the revenue, the manufacture is
laid under strict surveillance by the Excise. The duty on tiles was
repealed in the year 1833. Bricks can only be made at certain seasons,
in certain quantities, and even the screen through which the ashes are
sifted, to be mingled with the clay, must be made of wire of a certain
mesh. Bricks made larger than the standard measure of 8½ inches long,
4 wide, and 2½ thick, pay a higher duty than the common ones; if the
bricks are smaller than the proper size, the maker is fined heavily. No
duty is charged upon bricks made in Ireland.
About 1500 millions of bricks, 42 millions of plain, 23 millions
pan, and 6 millions of other tiles, are made annually in Britain. A
good moulder can make from 5000 to 6000 bricks in a day, from five
A.M. to eight P.M.
Within the present century, the annual use of bricks in Great Britain
has more than doubled, owing to the increase of[Pg 46] manufactories, and to
the construction of railroads and other public works.
Making Bricks by Machinery.
Within the last few years the making of bricks and tiles by machinery
has occupied much attention. A large number of patents has been taken
out for contrivances having this object in view. In some cases the
patentee has directed his attention chiefly to the preparation of
bricks for houses; while in others the making of tiles for draining
has been the chief object. A description of one or two of these
contrivances will give an idea of the general character of the whole.
The Marquis of Tweeddale, having his attention drawn to the importance
of employing draining tiles in agriculture, directed his talents
to the invention of a machine which should make them so quickly as
to enable them to be sold at a low price. After many attempts, he
perfected a machine which worked out this object, and at the same time
possessed all the facilities for making common bricks. The machine is
not constructed on the principle of imitating the manual operation,
by forming the bricks in moulds; but it arrives at the same end in a
different and remarkable manner. The principle adopted is, to form
and protrude, by mechanical means, a continuous fillet of clay, of
the proper width and thickness for a brick, and to stop this act of
protrusion for a moment, whilst a length of the fillet equal to that
of a brick is cut off. This is effected by the following mechanical
arrangements:—Two vertical roller-wheels, one of them being placed
over the other, and having an interval between them equal to the
thickness of the intended bricks or tiles, are made to revolve in
contrary directions; consequently they draw between them the clay with
which they are fed on the one side (either by hand or by any mechanical
contrivance), and deliver it on the other in a highly compressed state,
and in the form of a straight, smooth, and even fillet of the width of
the rollers. To provide for the squareness and smoothness of the sides
of the fillet, the sides of the aperture through which the clay passes
are made square and neat, so as to prevent the clay from spreading
out laterally. The clay is supported in a horizontal position whilst
delivered to and received from the rollers, upon a short endless band
on each side revolving on rollers rather close together; and in order
to facilitate this object the rollers themselves have bands, which are
prolonged in the direction of the endless bands in such a manner as to
meet them, and form one horizontal line of support. These bands are
made of fustian, the nap of which prevents the adhesion of the clay.
The rollers are so acted on by the[Pg 47] working power that they protrude
a length of clay equal to the required length of the brick or tile,
and then stopping, they allow time for a straight stretched wire to
descend and cut off the brick or tile, after which the motion between
the rollers is resumed, until another length is protruded, and so on
continuously. The fillet of clay is double the width for a brick, and a
wire is kept constantly stretched in the middle of its path, dividing
it into two fillets, so that two bricks are cut off at once. Two boys
are sufficient to remove the bricks as fast as they are produced, which
is at the rate of from fifteen to eighteen hundred in an hour. The
consistence of the clay is so much stiffer than that used for hand-made
bricks, that only half the time is required in the drying. From there
being so little water in the clay, and from its undergoing so much
compression, the bricks produced are remarkably dense and strong,
weighing half as much again as the ordinary brick, and absorbing only
one-seventh as much water.
Many machines have been contrived, having for their object the
formation of bricks on a principle somewhat analogous. Another class
of machines have effected the desired end in a different way,—viz.,
by forming each brick separately in a mould. A slight description of
one machine of this kind will illustrate all the others. The main
part of the machine is a horizontal wheel of large diameter. Round
the periphery of this wheel is a series of moulds, the exact size and
shape for bricks, placed nearly close together. Each mould has a loose
bottom, incapable of falling below the mould, but capable of rising
to its upper edge. The clay for the bricks, being properly prepared
in vessels at one side of the wheel, is made to fall into one of the
moulds, and the superfluous quantity is scraped off by a flat edge
which passes over the mould. The wheel rotates, and in its movement it
passes over a circular inclined plane, so constructed as to lift the
bottom of the mould up, so as to protrude the newly-made brick above
the mould, where it can be conveniently taken off by the hand. All the
different moulds, perhaps thirty or forty in number, are at any given
instant in different conditions as to their quota of clay; one is
receiving the clay, another is having the superfluous clay scraped off,
another has travelled so far round as to have the brick lifted halfway
out of it, another presents the brick wholly out of the mould, ready
to be taken off, while the others are travelling on empty to receive a
new supply of clay, all the moveable bottoms gradually sinking to their
proper position as the wheel proceeds, so that one rotation of the
wheel carries each mould through all its different stages of position.
[Pg 48]
The Processes of Bricklaying.
When we consider that a wall forty or fifty feet high, and not more
than two feet thick at the bottom, and fourteen or fifteen inches thick
at the top, is constructed of such small bodies as bricks, we may well
suppose that considerable nicety in workmanship must be requisite to
give stability to such a structure. The uniformity in size in the
bricks themselves, arising from their being copies of one
mould, is obviously the first condition that tends to the object; the
next is, that they should be put together in such a way as to cause
them mutually to adhere, independently of the tenacity of the mortar
employed; and lastly, the bricks must be set with great attention,
that their surfaces may be perfectly parallel and perpendicular to the
direction of gravity, for otherwise the wall composed of them, instead
of being truly perpendicular, would lean over on one side and fall. We
shall enter into some particulars on these points, but first we must
describe the tools and materials used in Bricklaying.
The trowel is the first and most indispensable of these tools.
It is a thin, flat, lozenge-shaped blade of steel, fixed into a handle.
It is with the trowel the workman takes up and spreads the layer
of mortar put between each brick, and with it he also cuts
the bricks so as to fit into any corner, or to adapt them to some
particular form; and to enable it to cut, or rather chip, such a hard
substance as burnt clay, and yet not break, it is necessary that the
blade should be of well-tempered hard steel. The square and
level are made of wooden rules put together; the first at
a true right angle, to enable the bricklayer to set out his walls
correctly perpendicular to each other,—the second is framed like a
⟂, with a plummet hanging in a slit in the upright piece; now, as
the two rules are correctly perpendicular to each other, it is clear
that when the first is set by means of the plumb-line perpendicular
to the horizon, the other will be truly horizontal. By means of this
important instrument, the workman guides his work, so that the wall he
is building shall be upright, and the courses of bricks composing it
horizontal. By means of this important instrument, the workman guides
his work, so that the wall he is building shall be upright, and the
courses of bricks composing it horizontal.
Mortar is the name given to the composition with which the
bricks are put together. Good mortar should be made of newly-burnt
quicklime from grey limestone, and of clean river-sand, in the
proportions of one-third lime to two-thirds sand. The lime is
slaked by pouring a little clean water on it, and when it falls
to powder by the chemical action, the sand is added gradually, and the
whole well mixed up with a spade, more water being used till the mass
is of the proper[Pg 49] consistence for spreading easily. As the adhesion
of the bricks depends on the mortar being applied before it begins to
set or harden, it should not be mixed till it is to be used.
When these simple precautions are attended to, the mortar becomes in
time as hard as stone, and the brick-work constructed with it is nearly
as indestructible. It was by taking this care with their materials that
our forefathers built walls that have stood uninjured for centuries. In
some of the cheap common buildings of the present day, mortar is too
often made from lime which has been so long from the kiln, that it is
nearly reconverted into a hydrate, and has lost the chemical quality
which renders it valuable; the sand, too, is taken from the road with
all its impurities, and the water from the nearest kennel. With such
materials a mass of mortar is made, and suffered to stand for several
days before it is used; the consequence is, that such buildings are
neither safe nor durable.
The mortar is made up by an assistant, called a bricklayers’ labourer,
and is taken by him to the spot where the workman wants it in what
is called a hod: this utensil, which consists of three sides
of a rectangular box fixed edgeways at the end of a long handle, is
expressly contrived to be carried on the man’s shoulder, and leave
his hands disengaged, to enable him thus loaded to ascend and descend
a long ladder; the hod being held standing upright on the handle,
the labourer can put bricks into it with his right hand, or another
assistant fills it with mortar.
The manner in which the bricks are arranged in the work, is termed
bond, and is of different kinds, according to the thickness of
the wall, and the purposes for which it is intended. The bond most
generally used is termed Flemish, in which the bricks are
laid alternately lengthwise and across the thickness of the wall,
the broadest side of the brick being laid horizontal, and never
edgeways, in building walls of every thickness. It was formerly
usual to lay a whole course of bricks lengthwise, and that above it
across; this disposition may be seen in old walls, and was termed
English-bond. In every kind of bond, the joints of the bricks of
one course are always made to fall over a brick in that beneath, or so
that one joint may never be immediately over another.
The site of a wall, or the walls of a building, being set out or
marked on the ground, a trench is dug in the earth for the foundations,
the width and depth being determined on from the thickness and height
of the superstructure, and from the nature of the soil. If this be
loose or soft, and the edifice be an important one, it is often
necessary to drive piles into the bottom of the trench, and lay a
course of oak planking on the[Pg 50] tops of these timbers, to form a firm
foundation for the wall; but if the nature of the ground do not require
such precautions, it is only necessary to level the bottom of the
trench carefully, as on this the stability of the wall will entirely
depend. A course of bricks is then laid dry on the earth, forming a
band twice the width of the lowermost thickness of the wall to be
built. This and the subsequent courses of the foundations should be
constructed of the best bricks; but unfortunately in common houses this
obvious requisite is entirely neglected. When this course is laid,
thin mortar, or mortar almost fluid and having but little sand in it,
is poured over the bricks, so as to flow into the joints and bind them
together by hardening: a second course is then laid on the first, only
narrower in width, and each subsequent course diminishes in the same
regular manner on each side, till the width is reduced to the thickness
at which it is proposed that the lower part of the wall should be
built. A cross section of these foundations thus constructed would
present the outline of a truncated pyramid, diminishing by regular
sets-off or steps; this part of a wall is called the footings.
For garden walls, or such as have no weight to carry, the footings need
not be made of so many courses, nor so broad, but every wall must have
two courses at least for a foundation.
The bricklayer makes use of a string stretched between two pins, to
enable him to keep his work straight; and he lays the outermost bricks,
those forming the face of the wall, carefully by this guide, setting
each brick alternately lengthwise and transversely, and spreading a
layer of mortar on the brick beneath, to form a bed for the new one to
lie on, and also a layer between each upright joint. It is usual only
to lay the outer bricks in this manner, and to fill up the interstices
of those forming the interior of the wall by pouring mortar on each
course previously laid dry with sufficient interval between them. The
workman as he proceeds, repeatedly makes use of his level and square;
by the former, he examines whether the face of his wall, and all the
corners, or arrises, are correctly perpendicular, and whether
the courses of bricks are laid horizontal.
Apertures, such as windows or doors which are to be formed in the
wall, are marked out on the wall when the work is built up to the
height where they are to commence; in carrying up the piers
between these windows, it will frequently happen that the width of the
pier is not precisely commensurate with a certain number of bricks or
half-bricks, but that a brick must be cut to bring the work to the
correct dimensions. This smaller piece is termed a closure, and
is usually placed within a brick or two of the arris of the[Pg 51] window or
door, and preserves its place for the whole height of the pier.
The thickness of brick walls is described by the number of bricks’
length they contain in that direction: thus a nine-inch wall is
one-brick thick; a brick-and-a-half wall is fourteen inches; a
two-brick wall is eighteen inches thick, and so on. The walls of small
houses are often only one brick thick, even when they are two stories
high; but usually a wall to be steady should decrease in thickness half
a brick at least every story, and for a large substantial building of
four or five stories, the main walls should be two-and-a-half bricks
at least on the basement story, and one-and-a-half at the top; but of
course the size of the apartments, or, in fact, the area of wall which
is to remain without any lateral support, must govern the strength of
it, as well as the total height to which it is to be raised.
When the wall is raised as high as the tops of the windows, &c., which
were left in it, these apertures must have arches turned over them, to
support the brick-work above. This leads us to consider the different
modes of constructing brick arches. When the width of the opening is
not above three or four feet, the arch over it is frequently straight
in its outline, or but slightly curved in the intrado or lower line.
The bricks which are to form the arch are rubbed down on a board
till they are brought to the proper wedge form. A piece of wood for
a centering is supported in the opening by upright slips: the upper
side of this centering is, of course, cut to the true camber or
curve the intrado of the arch is to have: the bricks are set upright
on this centre, and alternately, so as to break the joints. The face
of the arch, which is seen in the street over the windows and doors,
is constructed of the best bricks, carefully cut to a mould and set
in putty, or in thin mortar made of lime only: the rest of the
arch behind this face is less carefully constructed, and the bricks
are often not cut at all, but made to form an arch by the intervening
layer of mortar being spread unequally thick, or in a wedge shape.
When, however, a large arch is to be built of bricks, these are cut to
the proper level to form the wedge-shaped voussoirs. The construction
of groined arches in brick-work is the most difficult operation in the
trade. Each brick that forms the arris or intersection of the cross
vaults requires to be cut to a true form given by a drawing made to
the full size on a board. Another perhaps still more delicate piece
of workmanship for a bricklayer to execute is an oblique arch, such
as are often seen in the bridges over railroads and canals, which
cut established roadways obliquely. These arches are portions of a
cylinder, but the ends of the[Pg 52] cylinder, instead of being perpendicular
to the axis, are oblique to it, and this requires that the courses of
bricks composing the arch shall also not be parallel to the axis, and
therefore not in straight lines: hence, every brick has to be cut or
rubbed to a wedge form in two directions, and great nicety in this and
the subsequent operations are requisite in these structures.
Formerly columns, pilasters, cornices, niches, and similar
architectural embellishments, were constructed in brick-work, but stone
has now superseded brick for all embellishments; and the bricklayer’s
greatest skill is only required in the construction of arches, or
occasionally building a circular wall. The best specimens of elaborate
brick-work of the old school may be seen at the conservatory of
Kensington Palace, at Burlington House, and many other edifices of
the time of William and Mary, and Queen Anne, throughout the country.
The series of arches extending for nearly four miles on the Greenwich
Railway, and those for nearly an equal distance on the Blackwall
Railway, are perhaps among the best and most imposing specimens of
modern brick-work, and afford, in many places, beautiful examples of
the oblique arch. There are brick arches of a large span at each end of
the new London and Waterloo bridges.
Brick-work is measured by the rod, which is a superficial
area of sixteen and a half feet each side, or 272 square feet, at a
thickness of one-and-a-half brick, and all plain wall-work is reduced
to this standard for valuation. A rod of brick-work contains 4500
bricks, and together with the mortar required to build it, weighs about
15 tons 8 cwt. It differs in value from 10l. to 15l.,
according to circumstances.
Besides building walls, bricklayers are employed to tile roofs, set
coppers, pave stables, &c., build drains, and, in short, on all
occasions where bricks or tiles are the materials used.
Defects of Modern Brick Houses.
A writer in the endeavours, with much ingenuity, to show that the quality of English bricks and the system of bricklaying are very much influenced by the customary leasehold tenure of land. His remarks are as follow:—“Brick-making has been carried to great perfection by the Dutch, who have long been in the habit of forming their floors, and even, in some cases, of paving their streets with bricks. And it is remarkable how long their bricks will continue unimpaired in such situations. Though brick-making has long been carried on in England, and especially[Pg 53] in the neighbourhood of London, upon a very great scale, and though the process upon the whole is conducted in this country with very considerable skill, yet it must be acknowledged that English bricks are by no means so durable as Dutch bricks. We are disposed to ascribe this inferiority not so much to the nature of the materials employed in the manufacture of English bricks, as to the mode most frequently adopted in London of building houses. Few of the London houses, comparatively speaking, are freeholds. Most of them are built upon ground let for a lease of a certain number of years, which seldom exceeds ninety-nine years. After the expiration of this period the house becomes the property of the landlord who let the ground. Thus it becomes the interest of the builder to construct the house so that it shall last only as long as the lease. Hence the goodness of the bricks becomes only a secondary object. Their cheapness is the principal point. The object, therefore, of the brickmaker is not to furnish durable bricks, but to make them at as cheap a rate as possible. Accordingly, the saving of manual labour and of fuel has been carried by the makers of London bricks to very great lengths. We cannot but consider this mode of proceeding as very objectionable, and as entailing a much heavier expense upon London than would have been incurred had twice the original price been laid out upon the bricks when they were first used, and had the houses been constructed to last a thousand instead of a hundred years. No doubt certain advantages attend these ephemeral structures. The inhabitants are enabled, once every century, to suit their houses to the prevailing taste of the day; and thus there are no (few?) antiquated houses in London. But as the increase of the price of all the materials of building has more than kept pace with the increase of the wealth of individuals, it is to be questioned whether the houses are always improved when they are pulled down and rebuilt.”
[Pg 54]
Chapter IV.
THE ROOF. SLATES, AND OTHER ROOF COVERINGS.
We might, perhaps, under the designation of “Slates and Slating,” have included the operations usually understood to appertain to the construction of a roof. But modern improvements have rendered such a designation incomplete. We cannot now properly understand the mode of roofing houses without referring to many other substances besides slate.
Slate-Quarries.
Slate is the popular name for a variety of rocks which are sufficiently
stratified in their structure to allow of their being cleaved into
thin plates, a property which renders them valuable for a variety of
purposes. Slate has superseded the use of lead for covering roofs, even
of the largest buildings: from its lightness it is preferable to tile,
but the latter being cheaper, in flat countries which do not contain
rocks, but which yield brick-clay, slate in such localities is only
used on the better class of houses. In mountainous countries, a slaty
rock, which admits of being split thin, though not so much as clay
slate, is used under the name of shingle.
Besides being employed for roofing, slate is used in large slabs to
form cisterns, for shelves in dairies, for pavement, and similar
purposes, for which its great strength and durability, coolness, and
the ease with which it can be cleaned, owing to its non-absorbing
property, adapt it. The latter quality renders it also of great value
as a cheap substitute for paper, in the business of education; the
system of teaching in large classes in National and Sunday-schools
would be greatly fettered but for the use of slates.
The principal slate-quarries in Britain are in Wales, Cumberland, and
various parts of Scotland; the mode of working them is generally the
same. The rock is got out in tabular masses by means of large wedges,
and is then subdivided by smaller to the requisite thinness; the pieces
are roughly squared by a pick, or axe, and sorted, according
to their sizes, for roofing. The largest called imperial, are
about three and a half feet long, and two and a half wide; the smallest
average half those dimensions. When wanted for paving, &c., the large
blocks are sawn into thinner slabs, in the same manner as stone
or marble is.
A few words respecting the position and working of some[Pg 56] of the
slate-quarries may be appropriate, as illustrating the nature of this
remarkable geological formation.
A Slate-Quarry.
The most extensive slate-quarries in Great Britain are those near
Bangor, in Wales, from which slate is shipped to all parts of the
world. The slate occupies the greater part of the distance from Snowdon
to the Menai Straits. Upwards of two thousand men are employed in these
quarries; and the proprietor is said to gain from thirty to forty
thousand pounds per annum by them. Although this one is the largest,
yet there is one in Cumberland in which the slate is found more
remarkably situated. This is Hourston Crag, a mountain near Buttermere
Lake, about two thousand feet above the level of the lake, and nearly
perpendicular. On account of the difficulty of access, the workmen
take their provisions for the week, and sleep in temporary huts on the
summit. During the winter months they are generally involved in clouds,
and not unfrequently blocked up by the snow. The slate is conveyed
on sledges down a zigzag path cut in the rock, one man attending to
prevent the acceleration of the descent. When the slate is emptied at
the bottom the sledge is carried back on the man’s shoulders to the
summit.
Notwithstanding the value of slate, few quarries are worked to a very
great depth, or have subterranean galleries like mines. There is one,
however, near Charleville, in France, which is an exception to this
rule. The mouth of the mine is near the summit of a hill; the bed
inclines forty degrees to the horizon, and is about sixty feet in
thickness, but the extent and depth are unknown. It has been worked
by a principal gallery to the depth of four hundred feet, and many
lateral galleries have also been driven, extending about two hundred
feet on the side of the main gallery. Twenty-six ladders are so placed
as to give passage to the workmen and carriage for the slate. Of the
sixty feet which constitutes the thickness of the bed of slate, about
forty are good slate, the rest being mixed with quartz. The slate is
cut into blocks of about two hundred pounds each, called faix;
each workman, in his turn, carrying them on his back to the very
mouth of the pit, mounting all or part of the twenty-six ladders,
according to the depth of the bed where he may be working. When brought
to the surface, these blocks are split into thick tables called
repartons, by means of a chisel and mallet; and these repartons
are divided by similar means into roofing-slates.
Another remarkable slate-quarry in France, is situated near Angers.
The bed of slate extends for a space of two leagues, passing under the
town of Angers, which is in great[Pg 57] part built of slate; those blocks
which are the least divisible being employed in masonry. The quarries
actually explored are all in the same line, from west to east, as well
as the ancient pits, the bed of the best roof-slate rising to the
surface in this direction. Immediately under the vegetable earth is
found a brittle kind of slate, which, to a depth of four or five feet,
splits into rhomboidal fragments. A little lower is the building-stone,
which is a finer but scarcely divisible slate, and is employed in the
construction of houses, after it has been sufficiently hardened by
exposure to the air. At fourteen or fifteen feet from the surface is
found the good slate, which has been quarried to the perpendicular
depth of three hundred feet, without its lower limit being attained.
The interior structure of the slaty mass is divided by many veins or
seams of calcareous spar and quartz, fifteen or sixteen feet in length,
by two feet thick; these veins are parallel, and proceed regularly from
west to east in a position rising seventy degrees to the south; they
are intersected by other veins at intervals of a similar kind, but
whose rise is seventy degrees north; so that when the two series meet,
they form rhombs or half-rhombs. All the layers or laminæ of slate
have a direction similar to those of the veins of quartz, so that the
whole mass becomes divided into immense parallel rhomboids. The slate
is extracted in blocks of a determinate size, which are then divided
into leaves for roof-slates. When the blocks have been drawn from the
quarry, if they are left exposed to the sun or the open air, they
lose what is called the quarry-water, and then become hard and
untractable, and can only be employed as building-stone. Frost produces
a singular effect on these blocks; while frozen, they may be broken
with more ease than before; but if thawed rather quickly, they become
no longer divisible; yet this quality may be restored by exposing them
once more to the frost.
The Process of Slating.
When the blocks of slate for roofing have been split, and the laminæ
roughly squared, they are sorted, according to their size and quality,
and are brought to market under the quaint names of Imperial
slates, Duchesses, Countesses, &c., the first variety
being the largest. The best roofing-slates come from the celebrated
vale of Festiniog.
Slates are laid on battens, or thin narrow deal boards, which
are nailed horizontally on the common rafters of the roof, at equal
distances apart, which distance is governed by the size of the slate
to be employed. An entire board is nailed along the lowest edge of the
roof to receive the lead of the gutters, which are first laid, and then
the lowest course of slates are[Pg 58] nailed and pinned down to the
lowermost batten; so that two-thirds the length of the slate, at least,
shall lie over the lead. The next course of slates is then fixed, so
that every slate shall overlap two-thirds the depth of the course below
it, every slate being also laid over the joint, between two slates of
that undercourse. By this construction the rain that runs through the
joint between any two slates is kept from penetrating into the roof by
being received on the surface of the slate beneath that joint; and the
bottom course of slates is double, to continue the same principle down
to the lead gutter.
The slates are fixed to the battens by two copper nails and a wooden
pin when the work is well executed; holes being picked through each
slate for the nails to pass through.
Paper Roofs.
Although, as intimated in a former page, in covering our imaginary
dwelling with tiles or slates, we may seem to have done all that is
necessary in respect to “roofing,” yet we should leave our subject only
half treated if we were to omit mention of other contrivances which
have been partially acted on; such as the use of paper, of asphaltum,
and various other substances.
About thirty years ago, Loudon published a pamphlet, in which
he described the mode of preparing paper for roofs, and discussed
the various arguments for and against its adoption. His description
had immediate relation to a series of paper roofs in a large farm at
Tew Lodge, in Oxfordshire, and comprised the following among other
particulars.
[Pg 59]
Paper roofs may be made very flat, being raised no higher than just
sufficient for throwing off the water. Instead of tile, slate, or
thatch, they are covered with paper, prepared by immersion in a mixture
of tar and pitch. In the first place, pieces of wood called “couples,”
are laid across the walls of the building, rising two inches and a half
to the foot to obtain a drainage obliquity; these couples vary from two
or three to six inches square, according to the size of the roof. On
the couples are placed horizontal rafters, about two inches square; the
distance between the couples being from five to eight feet, and between
the rafters about eighteen inches; the couples are nailed to the wall
plate, and the rafters to the couples. At Tew Lodge, the rafters used
were young larch-trees, sawn up the middle, cut to the proper lengths,
and prepared so that the upper surface should be level. On the rafters
are placed thin boards, from a half to five-eighths of an inch in
thickness; these boards are nailed to the rafters, not horizontally
as for slating, but in a direction from the eaves to the ridge of the
roof. In some cases substitutes for thin boards may be used; such as
close copse-wood hurdles, plastered over; or common plaster-laths.
The paper employed may be any common, coarse, strong kind; that kind
used by button-makers being favourable for the purpose. It is prepared
as follows: a boiler or cauldron, three feet wide by two deep, placed
over a fire, is filled to within six inches of the top with tar and
pitch, in the proportion of three parts of the former to one of the
latter; the fire being applied and the mixture made to boil, the paper
is immersed in it one sheet at a time, and then laid in a stack or pile
with such a slope as to allow it to drain, a little grease of any kind
being placed between the sheets to prevent their adhering; and when dry
the paper is similarly treated a second time. The paper thus prepared
is then nailed down to the roof. The workman begins at the eaves, and
allows three inches for being turned down and nailed underneath the
end of the board, which boards project an inch over the first rafter.
If the paper be common, coarse, wrapping paper, it is laid on much the
same as slate, so that when finished it will remain in double thickness
all over the roof; but if thicker paper be employed, it is only made
to overlap about three inches in each layer. Every sheet is fixed down
with four nails about an inch in length, having broad flat heads.
On the paper thus fixed is laid a composition consisting of two parts
of tar to one of pitch, thickened to the consistence of paste, with
equal parts of whiting and powdered charcoal. The composition being
well boiled and kept constantly stirred, it is spread over the roof
with a hempen mop as[Pg 60] quickly as possible on account of the speedy
cooling. When properly laid on and dried, the composition totally
conceals the joints of the paper, and forms a smooth and glossy
black covering an eighth of an inch in thickness. Sometimes, while
the composition is yet wet, sand, dust, or ashes are strewed on, to
increase the substance, and shield the composition from the action of
the sun.
Loudon enumerates as the advantages of this roof—economy,
durability, and elegance. The economy is shown by the circumstance
that, on account of the lightness of the paper, less massive walls
and timbers are required than for other kinds of roof. The expense at
Tew Lodge was from fourpence to tenpence per square foot, everything
included. It is one result of the flatness of the roof, that ten square
feet will cover as much as fourteen feet at the usual pitch of slated
roofs. As to the durability, many proofs are adduced to support it.
A paper roof to a church at Dunfermline remained forty years without
requiring any repairs; and several warehouses at Greenock, Deal, Dover,
and Canterbury, had paper roofs, which were known to stand from ten
to twenty years. Loudon considered that, from the flatness of the
roofs, and from other circumstances connected with the appearance
of the prepared sheets, the paper roofs were more fitted to join
harmoniously with certain styles of architecture than slated roofs.
Objections have been made to this kind of roof, on the ground that it
is liable to be blown off by high wind, and still more that it is very
inflammable. With regard to the former, Loudon states that if the
roof be properly made there is little danger of its being removed by
high wind. In reference to the second objection, he states:—“They seem
to me not so liable to set fire to as thatch. Pitch (especially if
coated over with sand or smithy ashes) will not be lighted by a spark,
nor even by the application of a slender flame, as will that material;
though, on the other hand, when lighted, it will unquestionably
burn with greater velocity than any species of thatching…. In the
steward’s house and men’s lodge wood is constantly used as fuel, which,
though more dangerous for emitting sparks than coal, yet no accident
has or is ever likely to happen to the roof. In my house, where coals
were chiefly used, the chimneys have been repeatedly set on fire to
clean them, without the least accident happening to the roof.”
Many years afterwards, when Loudon published his elaborate
, he
briefly sketched some of the forms of roof which have more or less
recently come into use. These we must here notice.
[Pg 61]
Terrace Roofs.
Terrace roofs have been much used in and about London. They are formed of thin arches of tiles and cement, supported on cast-iron bearers or ribs, which are placed about three feet apart. The arch is composed of three courses of common plain tiles, bedded in fine cement without sand. In laying the tiles, laths or small slips of wood are used, resting on temporary bearers between the iron ribs; the laths being shifted as the work advances, in the course of about half an hour after the tiles are laid. Particular attention is required in bonding the tiles both ways; and they are rubbed down closely upon each other, much in the same manner as a joiner glues a joint. Sometimes these terrace roofs are coated with a layer of coarse gravel, and then with nine inches of good soil, so as to form a terrace garden. The roofs of two taverns at Hungerford Market are formed of these cemented tiles.
Asphalte Roofs.
Asphalte or bitumen has come into use as a material for roofs. It had been employed for various purposes in France for many years, but did not attract much attention till within the last eight or ten years. It is now in very general use in that country for foot pavements, flat roofs, and water-cistern linings; and in England it has also been a good deal used for the same purposes, and for barn-flooring. The particular modes in which it is employed for floors and pavements we need not here consider, but it has been used for roofs in the following manner. Pocock has patented a “flexible Asphaltic roofing,” intended to supersede the use of slates, tiles, zinc, thatch, &c., in the covering and lining of farm-buildings, sheds, cottages, and other erections; and it is approved for its durability, lightness, and economy. The weight of this material being only sixty pounds to the square of one hundred feet, the walls and timbers to support it need to be but half the usual substance; it is also a non-conductor of heat, impervious to damp, and will bear a heat of two hundred and twenty degrees without injury. This peculiar material is said to be formed of asphalte mixed with the refuse felt of hat manufactories, compressed into thin plates.
Scotch Fir Roofs.
Scotch fir roofs are occasionally made. The method of giving durability to the timber for this purpose consists in first cutting the wood to the required size, and then steeping[Pg 62] it for a fortnight in a pond of lime-water; it is found that the acid contained in the wood becomes crystallized by combining with the alkali of the lime. Sir Charles Menteath is said to have some farm buildings which, although roofed with Scotch fir forty years ago, are as well protected now as when the roofs were first laid on; the wood having been previously steeped in lime-water. The sulphate of copper, the chloride of zinc, the corrosive sublimate, and the various other chemical substances which have been recommended of late years as means for preventing the decay of timber, will possibly render the use of timber roofs more practicable than it has been hitherto considered.
Iron Roofs.
Roofs of iron are in great request at the present time. One of
these sorts of roofs may be formed of three kinds of cast-iron plates.
The first, called the “roof-plate,” is shaped with three of its sides
turned up and one turned down, and is made tapering narrower towards
one end; the second, called the “low-ridge plate,” has two of its
sides turned up and the other two turned down; the third, called the
“high-ridge plate,” has all its sides turned down, and is formed with
an angle in the middle, so as to slope each way of the roof. Such a
roof may be made very flat, inasmuch, that for a house twenty feet
wide, the height of the roof in the middle need not exceed two feet;
no boarding is required, the plates resting without either cement or
nails on the rafters. From the manner in which the edges of the plates
overlap, there is no risk of contraction or expansion.
Some of the iron roofs recently made are on the principle of those
used in Russia, of which the following description has been given in
the :—“Sheet-iron coverings
are now universally made use of in all new buildings at Petersburgh,
Moscow, &c. In the case of a fire, no harm can come to a house from
sparks falling on a roof of this description. The sheets of this iron
covering measure two feet four inches by four feet eight inches, and
weigh twelve pounds and a half avoirdupois per sheet, or one pound
five ounces each superficial square foot. When the sheets are on the
roof, they measure only two feet wide by four feet in length: this is
owing to the overlapping. They are first painted on both sides once,
and, when fixed on the roof, a second coat is given. The common colour
is red, but green paint, it is said, will stand twice the time. Small
bits or ears are introduced into the laps, for nailing the plates to
the two-inch square laths on which they are secured. It takes[Pg 63] twelve
sheets and a half to cover one hundred feet, the weight of which is
one hundred and fifty pounds—the cost only £1 15_, or about
threepence per foot.”
Iron roofs are now often made of _corrugated or furrowed
sheet-iron. In this form the iron is impressed so as to present a
surface of semi-circular ridges with intervening furrows lengthwise of
the sheets. By this means, a piece of sheet-iron, which, as a plain
flat surface, has no strength but in its tenacity, becomes a series of
continued arches abutting against each other; and the metal, by this
new position, acquires increased strength. Iron so furrowed is deemed
preferable to common sheet-iron for covering a flat-roof, because the
furrows will collect the water and carry it more rapidly to the eaves.
But there are greater advantages than this. If the furrowed sheets be
bent into a curved surface, convex above and concave below, they will
form an arch of great strength, capable of serving as a roof without
rafters or any other support, except at the eaves or abutments. Iron
roofs measuring two hundred and twenty-five feet by forty have been
constructed in this manner. To increase their durability the iron
sheets are coated with paint or tar.
Zinc and other Metallic Roofs.
Additions are made every year to the number of contrivances for forming
metallic roofs, among which is one now the subject of a patent, for the
use of galvanized iron. In this case the aid of the electric
agent is employed to give iron sheets an amount of durability which
they do not possess in their natural state.
Zinc has been much employed within the last few years as a material for
roofs. Its availability for this purpose rests partly on its superior
lightness as compared with lead, and its superior condition under the
action of the atmosphere as compared with iron. The latter quality
arises thus; after the zinc has been covered with a thin film of oxide
by the action of the atmosphere, it suffers no further change from long
exposure; so that the evil of rust checks itself. At the temperature
of boiling water, zinc sheets, which are brittle when cold, become
malleable, and their availability for roofs is thereby increased. The
property which zinc has, however, of taking fire at a temperature of
about 700° Fahr., rather detracts from its value as a material for
roofs.
Thatch Roofs.
The most common material employed as thatch is either the straw of
wheat, rye, or other grain, or reed, stubble, or[Pg 64] heather. The straw
of wheat and rye, when well prepared and laid, forms the neatest and
most secure thatching; the former being preferable to the latter in
smoothness, suppleness, and durability. Barley-straw is placed next
to rye in fitness for thatch, and oat-straw the lowest of the four.
The reed is a very durable material for thatch, but is generally too
expensive. It has been stated that, in Norfolk, where the reed is a
favourite material for thatch, a reed roof will lie fifty years without
wanting repair, and that, with very slight attention, it will last for
a whole century. Viewed in this light, a reed roof may probably be
considered economical.
The method of thatching with reed, (which is one of the best and most
difficult specimens of the thatcher’s art,) has been thus described.
No laths being made use of as a support to the thatch, a few of the
longest and stoutest reeds are scattered irregularly across the naked
spars as a foundation whereon to lay the main coat; and thus a partial
gauze-like covering is formed, called the fleaking. On this
fleaking the main covering is laid, and fastened down to the spars by
means of long rods called sways, laid across the middle of the
reed, and tied to the spars with rope-yarn or with brambles. In laying
on the reed, the workman begins at the lower corner of the roof on his
right hand, and keeps an irregular diagonal line until he reaches the
upper corner on his left; a narrow eaves-board being nailed across
the feet of the spars, and some fleaking scattered on. The thatcher
begins to “set his eaves” by laying a coat of reed, eight or ten inches
thick, with the heads resting upon the fleaking and the butts upon
the eaves-board. He then lays on his sway, or rod, about six or eight
inches from the lowest point of the reed, whilst his assistant, on the
inside, runs a needle threaded with rope-yarn close to the spar and to
the upper edge of the eaves-board. The thatcher draws it through on one
side of the sway and enters it again on the contrary side both of the
sway and of the spar. The assistant, in his turn, draws it through,
unthreads it, and, with the two ends of the yarn, makes a knot round
the spar, thereby drawing both the sway and the reed tight down to the
roof; whilst the thatcher above, beating and pressing the sway, assists
in consolidating the work. The assistant, having made good the knot
below, proceeds with another length of thread to the next spar, and so
on till the sway is bound down the whole length, that is, about eight
or ten feet. This being done, another stratum of reed is laid upon the
first, so as to make the entire coat eighteen or twenty inches thick
at the butts; and another sway is laid on and bound down about twelve
inches above the first.
[Pg 65]
When the eaves are completely set they are adjusted and made even by
an instrument called a legget. This is made of a board eight
or nine inches square, with a handle two feet long adjusted to its
upper surface in an oblique position. The face of the legget is set
with large-headed nails, and these enable the workman, by using the
instrument somewhat as if it were a turf-beating tool, to lay hold of
the butts of the reed and to adjust them in their places. When the
eaves are thus shaped, the thatcher lays on another stratum of reeds,
and binds it down by another sway somewhat shorter than the last, and
placed eighteen or twenty inches above it; and above this, others, in
successive rows, continuing to shorten the sways until they diminish to
nothing, and a triangular corner of thatching be formed. After this the
remaining surface of the roof is similarly done.
In order to finish the ridge of the roof, a cap of straw
is adjusted to it in a very careful manner. In this operation the
workman begins by bringing the ridge to a sharp angle, by laying straw
lengthwise upon it: and to keep this straw in its place, he pegs it
down slightly with “double-broaches,” which are cleft twigs about
two feet long and half an inch thick, sharpened at both ends, bent
double and notched, so as to clasp the straw on the ridge. This done,
the thatcher lays a coat of straight straw six or eight inches thick
across the ridge, beginning on either side at the uppermost butts of
the reeds, and finishing with straight handsful evenly across the
top of the ridge. Having laid a length of about four feet in this
manner, he proceeds to fasten it firmly down, so as to render it proof
against wind and rain; this is done by laying a “broachen-ligger”
(a quarter-cleft rod, half an inch thick and four feet long) along
the middle of the ridge, pegging it down at every four inches with
a double-broach, which is first thrust down with the hands, and
afterwards driven with the legget or with a mallet. The middle ligger
being firmly laid, the thatcher smooths down the straw with a rake and
his hands, about eight or nine inches on one side; and at six inches
from the first, he lays down another ligger, and pegs it down with a
similar number of double-broaches, thus proceeding to smooth the straw
and to fasten on liggers at every six inches, until he reaches the
bottom of the cap. One side being thus finished, the other is similarly
treated; and the first length being completed, others are done in like
manner, till the farther end of the ridge is reached. He then cuts off
the tails of the straw neatly with a pair of shears, level with the
uppermost butts of the reed.
When straw or heather is used for thatching, the material is laid on in
parallel rows, much the same as the reeds, but the mode of fastening is
generally somewhat different.
[Pg 66]
Chapter V.
THE WOOD-WORK. GROWTH AND TRANSPORT OF TIMBER.
The operations of the carpenter and joiner in the preparation of the
wood-work of a house are quite as important as those of the mason or
bricklayer. It would not be possible in this little volume to trace
clearly all the different processes connected with the building of a
house as they occur in practice; for the bricklayer and the carpenter
combine their work, as it were, step by step. But as the bricklaying
and the slating, or tiling, relate principally to the exterior of the
house, and the carpentry work to the interior, we have thus a line of
separation, which will greatly contribute to the clearness of these
details.
As on a former occasion we noticed the operations of the quarry,
whence the builder is supplied with stone, slate, &c., it will now be
interesting to give a few details respecting the growth and transport
of timber.
The Oak as a Timber Tree.
It is obvious that in every country native timber is preferred,
provided it can be obtained in sufficient quantity at a cheap rate;
if not, it is imported from other countries. In Britain, the first
and most important of all trees is, of course, our own oak, of which
we have two species and several varieties, belonging to the genus
.
The two species of oak natives of Britain, though greatly resembling
each other in general appearance, may yet very readily be
distinguished, when once their specific characters are pointed out. As
these two species are very commonly confounded together, and as one of
them is believed to afford a far more valuable timber than the other,
it may be useful to note their difference, and exhibit the characters
by which each may be known.
The true British oak, , ( 1) bears its acorns
on a stalk, or peduncle ( 1, A), and hence it
is sometimes called , but its leaves grow
close to the stem, without a footstalk, or at least with a very short
one. In the other native species ( 2), these two characters are
reversed: the leaves grow upon a footstalk, while the acorns are
produced sessile, that is, sitting close to the stem ( 2,
A); from which latter character this species has acquired the
name of .
The above characters will, for the most part, be found[Pg 67] pretty
constant. At the same time, it may be remarked, that the oak is a
tree subject to great variations; and accordingly individuals of
each species occasionally occur, which in their characters are found
more or less to approach those of the other. ,
for example, sometimes bears its acorns almost close to the stem,
and sometimes will bear them on a short
footstalk. The leaves, too, of each, frequently vary in the length of
the petiole, or[Pg 68] leafstalk. But in a general way (as already
stated), each kind may be readily distinguished by the above obvious
points of difference.
Both species are common in Britain, though
appears to be not so generally distributed as the other; in many
districts its growth seems to be principally confined to woods and
coppices, where it sometimes occurs even in greater abundance than the
common species. is believed to afford the more
valuable timber of the two, owing, probably, to its being of slower
growth. It is doubtful, however, whether the respective merits of each,
in point of durability of timber, have yet been fairly put to the
test. Where oak is grown in coppices, to be cut down periodically for
poles, is at least a valuable, perhaps a
preferable tree, on account of its more rapid and cleaner growth.
No certain specific characters, we are aware, can be derived from
the mere size or shape of the acorns, or of the leaves. It may be
mentioned, however, as a general, though not a constant rule, that
usually bears very small acorns, and
that its leaves are, for the most part, larger, and more regularly
laciniated or notched, and consequently handsomer, as individual
leaves, than those of . The foliage of
the latter species, however, taken as a whole, is by far the more
beautiful; its leaves, being smaller, and growing close to the stem,
and not on footstalks, combine better, form more dense and compact
masses, and exhibit to greater perfection those exquisite tufts, or
rosettes, which constitute one of the peculiar charms of oak foliage.
The oak is far less used in civil architecture than formerly, although
there are certain purposes in building to which it is still applied;
but owing to its value and the demand for it for ships, and to the
great labour required to work it, its place is now supplied by
fir. The best oak is that which grows on cold, stiff, clayey
soils, and is the slowest in arriving at maturity; and the colder the
climate, or the higher above the level of the sea the tree grows,
provided it be not stunted from severity of climate, the better the
timber: hence Scottish and Welsh oak is more esteemed than that from
the middle or southern counties of Britain. Our own island does not
produce this timber in sufficient abundance to supply the demand,
and large quantities of oak are imported from different countries,
especially from Prussia and Canada. There are four kinds of oak used in
the Royal Dock-yards,—Welsh, Sussex, Adriatic, and Baltic,—besides
two others, termed African oak, employed in different parts of the
vessels, according to the qualities requisite for the particular
purpose.[Pg 69] Next to our own oak, that from the shores of the Baltic is by
far the most esteemed.
In domestic architecture, oak is only used in the largest and best
buildings, occasionally for the principal beams; but its chief use is
for door and window frames, sills, sleepers, king-posts of roofs, for
trussing fir girders, for sashes, for gates of locks, sluices, posts,
piles, &c. The timber called African oak, used in the navy, is
wood of a different genus.
Wainscot is the wood of a species of oak, imported from Russia
and Prussia in a particular form of log.
Teak is the produce of a tree of the genus . is one of the largest Indian trees, and one of the most
valuable, on account of its excellent timber. The trunk is neat,
lofty, and of an enormous size; the leaves about twenty inches long
and a foot or more wide; the flowers small, white, and fragrant, and
collected into very large panicles. It is a native of various parts of
India, and was introduced into Bengal by Lord Cornwallis and Colonel
Kydd. The wood of this tree has been proved by long experience to be
the most useful timber in Asia; it is light and easily worked, and
at the same time strong and durable. It is considered equal to oak
for ship-building, and has some resemblance to it in its timber; many
vessels trading between this country and India are constructed of it.
That which grows near the banks of the Godavery is beautifully veined,
closer in the grain, and heavier than other varieties. “On the banks
of the river Irrawaddy, in the Birman empire, the teak forests are
unrivalled; and they rise so far over the jungle or brushwood, by which
tropical forests are rendered impenetrable, that they seem almost as if
one forest were raised on gigantic poles over the top of another. The
teak has not the broad strength of the oak, the cedar, and some other
trees; but there is a grace in its form which they do not possess.”
A specimen of this tree was introduced into the Royal Gardens at Kew
about seventy years ago; but from the coldness of our climate it can
never become a forest-tree in this country.
Valuable as teak is found to be in ship-building, it has not yet been
used in domestic building to any extent. From sixteen to eighteen
thousand loads of teak are annually imported into Britain from India,
principally for the Royal Dock-yards, this wood being used for certain
beams and pillars in ships.
The Fir and Pine as Timber Trees.
Fir, or Pine, ranks next to oak for its valuable
qualities, and if its universal application be taken into
consideration, it[Pg 70] might be thought even superior in importance. It is
used for every part of houses, and extensively in ship-building, in
the fittings-up, while it constitutes the only material for masts, for
which purpose its lightness, and the great length and straightness of
the trunk, peculiarly fit it.
Pine, or fir, is imported into this kingdom under the various names
of timber, battens, deals, laths, masts, yards, and spars, according
to the size or form into which the tree is sawed. It is called
timber when the tree is only squared into a straight beam of
the length of the trunk, and from not less than eight or nine inches
square, up to sixteen or eighteen square; fifty cubic feet is a load of
timber. Deals vary in length and thickness from eight to sixteen feet,
eleven inches wide, and from one and a half to three and a half inches
thick. Four hundred superficial feet of one and a half inch plank make
a load. Battens are small long pieces of fir about three inches
wide and one inch thick. Masts, yards, and spars, are the trunks of
small trees simply barked and topped.
The pine is, generally speaking, an evergreen, and the wood becomes
harder and more durable when the situation is cold, and also when the
growth of the tree is slow. Norway, Sweden, the shores of the Baltic,
and Canada, are the chief localities of the forests of pine. England
is supplied principally from Canada, not because the timber from that
country is better than that derived from the north of Europe, but
because our timber duties fall heavily on the European pine, the object
of the legislature being to encourage the importation of pine from our
North American colonies.
Almost the whole of what is now called Canada was once an immense
pine forest. With respect to the Baltic region, Clarke said, that
if we take up a map of Sweden, and imagine the Gulf of Bothnia to be
surrounded by one contiguous unbroken forest, as ancient as the world,
consisting principally of pine trees, with a few mingling birch and
juniper trees, we shall have a general and tolerably correct notion of
the real appearance of the country. The same writer observed, that the
King of Sweden might travel from sunrise to sunset through some parts
of his territories, without meeting any other of his subjects than pine
trees.
The Norway Spruce Fir.
The species of Spruce Fir (), represented in the
engraving, has been known as a British tree for more than three hundred
years, but Norway seems, as far as it can be ascertained, to be its
native country. It differs from the[Pg 71] Scotch fir in general appearance,
as well as in the structure of its leaves and cones. The beautiful
feathery appearance of its foliage is very striking, but the extreme
regularity of its form rather detracts from the beauty of a landscape
when it is too often repeated; it is easily known by its long pendulous
cones, as well as by its formal shape. The spruce fir is found in
great abundance in all the Norwegian forests; it is[Pg 72] also spread over
the whole of the north of Europe, and part of Asia, and it occurs on
most of the mountain-ranges of both these quarters of the globe; in
favourable situations it attains a great height, as much at times as
150 feet.
The Norway Spruce Fir.
The spruce grows more rapidly than any other of the fir tribes; its
wood is extremely tough and strong, and answers well for masts and
spars, but it is not so valuable when cut into planks as that of other
species. It does not attain the same size in Britain as in colder
climates, the tree perhaps being weakened by the loss of its sap,
which in hot weather is discharged through the bark in considerable
quantities. The more protracted season of growth, and the greater
difference between the temperature of the day and the night, must have
an effect upon it, and judging from the situations which it prefers
on the Continent, the summer rains of England cannot be by any means
favourable. The almost continual day in the Polar countries, while
vegetation is active, produces a uniformity of temperature, and a
consequent uninterrupted growth day and night, while in countries
farther south, the vegetable action is checked every night, and renewed
again every morning, especially in the early part of the season, when
such alternations are most dangerous.
1 1 Male Catkins, or Blossoms.
2 2 2 Cones containing the Seed.
[Pg 73]
The Norway Spruce is called by the French the Pitch Spruce, from its
yielding the Burgundy Pitch of commerce. To obtain this, parts of the
bark are removed in the spring, and the resin exudes in greater or
smaller quantities, according to the state of the tree; this is scraped
off from time to time. After a sufficient quantity has been collected,
it is melted in hot water, and strained through bags to separate the
impurities. If the strips of bark which are removed are narrow, the
trees will continue to yield for several years.
The Norway Spruce, and all other trees of the fir tribe, are propagated
by means of seeds. These are to be sown rather thinly about the
middle of March, in a shady well-sheltered border; towards the autumn
the ground is to be carefully weeded, and a quantity of rich earth
strewed lightly over the whole. During the winter, if the frosts are
very severe, the young plants ought at times to be protected from the
severity of the weather. In the next spring, and during the months
of May and June, the young plants will be much assisted by frequent
waterings, and in the autumn the ground must be again cleaned. In
the succeeding spring, when their heads begin to swell, they may be
removed. At four years old they may be transplanted again to a spot
of good land, and placed in rows two and a half feet asunder, and
fourteen or sixteen inches distant in each row. Three years after they
will again require to be transplanted four feet asunder, and so on,
increasing the space between the trees at each remove, until the young
ones are fourteen or sixteen feet in height.
The Scotch Fir.
One of the most useful kinds of pine is the
(wild pine), generally known as Scotch fir. It is this tree which
produces that kind of wood so extensively useful to the carpenter under
the name of deal. The term “deal” implies timber squared into a
convenient size for exportation, and it is in the form of deals that
the wood of which we are now speaking is imported into England from
Norway and the Baltic. The best part of this wood is near the root;
and the roots themselves are valuable for many purposes. It is of this
wood that the bodies of violins and the sounding boards of musical
instruments generally, are made: the grain of the wood formed by the
annual layers being very straight and regular. In trees which have not
arrived at maturity, there is a portion of sap-wood next the bark; this
sap-wood is converted into ligneous matter in about two or three years
from its formation.
[Pg 74]
The Scotch Fir.
The Scotch Fir, or Pine, is not peculiar to Scotland, but is common
to all the mountain-ranges of Europe; in low damp situations it never
thrives, but delights in the exposed summits of the loftiest rocks,
over which the earth is but thinly scattered; there its roots wander
afar in the wildest reticulation, whilst its tall, furrowed, and often
gracefully-sweeping, red and gray trunk, of enormous circumference,
rears aloft its high umbrageous canopy.
[Pg 75]
The fir was a very great favourite with Gilpin, who considered it, as
it really is, to be under favourable circumstances, a very picturesque
object in a landscape: the earnestness with which he defends its
character is peculiarly forcible; he says, “It is a hardy plant, and,
therefore, put to every servile office. If you wish to screen your
house from the south-west wind, plant Scotch firs, and plant them
close and thick. If you want to shelter a nursery of young trees,
plant Scotch firs, and the phrase is, you may afterwards weed them
out at your pleasure. This is ignominious. I wish not to rob society
of these hardy services from the Scotch fir, nor do I mean to set it
in competition with many trees of the forest, which, in their infant
state, it is accustomed to shelter; all I mean is, to rescue it from
the disgrace of being thought fit for nothing else, and to establish
its character as a picturesque tree. For myself, I admire its foliage,
both the colour of its leaf and its mode of growth. Its ramification,
too, is irregular and beautiful.”
The practice of planting this tree in groups is the cause to which its
unfavourable character, as a picturesque object, may be attributed, the
closeness of growth causing the stems to run upward without lateral
branches. The hilly regions of the whole of Great Britain and Ireland
were formerly covered with vast forests, a great portion of which
consisted of fir-trees. Of these ancient forests some remains still
exist; in Scotland, the relics of the Rannock forest, on the borders
of the counties of Perth, Inverness, and Argyle, are well known:
these consist of the roots and a few scattered trees, which are still
found in situations of difficult access. This forest appears to have
stretched across the country, and to have been connected with the woody
districts of the west of Scotland. The Abernethy forest, in Perthshire,
still furnishes a considerable quantity of timber.
“At one time,” we quote Sir Thomas Dick Lauder, Bart., “the demand for
it was so trifling, that the Laird of Grant got only twenty pence for
what one man could cut and manufacture in a year. In 1730 a branch of
the York Buildings Company purchased seven thousand pounds’ worth of
timber, and by their improved mode of working it, by saw-mills, &c.,
and their new methods of transporting it in floats to the sea, they
introduced the rapid manufacture and removal of it, which afterwards
took place throughout the whole of the sylvan districts. About the
year 1786 the Duke of Gordon sold his Glenmore forest to an English
company for 10,000l. This was supposed to be the finest
fir-wood in Scotland. Numerous trading vessels, some of them above
five hundred tons burden, were built from the timber of this forest,
and[Pg 76] one frigate, which was called the Glenmore. Many of the trees
felled measured eighteen and twenty feet in girth, and there is still
preserved at Gordon Castle a plank nearly six feet in breadth, which
was presented to the Duke by the Company. But the Rothienmurchus forest
was the most extensive of any in that part of the country; it consisted
of about sixteen square miles. Alas! we must indeed say, it was, for
the high price of timber hastened its destruction. It went on for many
years, however, to make large returns to the proprietor, the profit
being sometimes 20,000l. a year.”
Leaves and Male Blossom of Scotch Fir.
Cone of Scotch Fir.
Besides the forest we have mentioned, there are still in existence
other tracts of land in different parts of Scotland covered with this
timber. The attention which has been drawn to the value of the Scotch
fir has been an inducement to proprietors of land to cause extensive
plantations to be formed on suitable spots; but Nature herself takes
measures to perpetuate her work where the hand of man has carried
destruction; for, after the old trees have been felled and carried off
the ground, young seedlings come up as thick as in the nurseryman’s
seed bed.
The timber supplied by the Scotch fir is called Red Deal, and the
uses to which it is applied render it necessary that the stem should
be straight, and close planting materially assists in this object, by
preventing the possibility of the trees flinging out their lateral
branches; this, as we have already noticed, disfigures the tree in
the eye of an artist, however[Pg 77] much it may delight that of a timber
merchant. The straightest and cleanest-grown trees are selected for
masts, spars, scaffold-poles, &c., while the largest sticks
are sawed into planks for various purposes. Its wood is very durable,
and resists the action of water excellently. The persons employed at
different times in the endeavour to rescue the cargo of the Royal
George, which foundered off Spithead, in the year 1782, discovered
that the fir-planks had suffered little, if any injury, while the
other timbers of the vessel had been much acted upon by the water and
different species of worms.
In Holland this tree has been used for the purpose of preparing the
foundations of houses in their swampy soil; 13,659 great masts of this
timber were driven into the ground for the purpose of forming the
foundation of the Stadthouse at Amsterdam. But it is not only for its
timber that we are indebted to this tree; those useful articles, tar,
pitch, and turpentine, are all yielded by its sap.
Transport of Timber from the Forests.
Probably but few of our readers think of the means by which
timber is conveyed from the forest where it grows, to the spots
where it is to be applied to the purposes of building. And yet it
must be evident that the means of transport form a matter of no small
importance. We know that our timber-yards are plentifully supplied
with the various kinds of wood necessary for building; and that the
timbers are shaped by the axe and the saw. But, in most cases, the
wood which we employ is brought from foreign countries, often many
miles inland. It is conveyed across the ocean in ships; but the mode of
transporting it from the forests where it grows to the ports where it
is to be shipped, is a curious subject, and one well worthy of a little
attention.
The main circumstance that forms the groundwork of all the plans
adopted for this purpose is, that nearly all kinds of wood are, bulk
for bulk, lighter than water, and will consequently swim on its
surface. Now as all countries are, more or less intersected by rivers,
which flow from the interior into the sea, a very simple and economical
mode of transport for timber is at once attained, by causing it to
float down running streams, either by the mere force of the descending
water, or by the aid of mechanical agents. There is no necessity that
each piece of wood should be floated separately down the stream; for
they may be fastened together and steered down the middle of the river,
in the form of a long and broad raft.
[Pg 78]
Beckmann says: “It is probable that the most ancient mode of
constructing vessels for the purpose of navigation, gave rise to the
first idea of conveying timber in the like manner; for the earliest
ships or boats were nothing else than rafts, or a collection of beams
and planks bound together, over which were placed deals. By the Greeks
they were called schedai, and by the Latins rates; and
it is known, from the testimony of many writers, that the ancients
ventured out to sea with them, on piratical expeditions, as well as
to carry on commerce; and that after the invention of ships, they
were still retained for the transportation of soldiers, and of heavy
burdens.”
There are some passages in the Bible which allude to the floating of
wood. 1 Kings v. 9: “My servants shall bring them down from Lebanon
unto the sea; and I will convey them by sea in floats unto the place
that thou shalt appoint me.” 2 Chron. ii. 16: “And we will cut wood out
of Lebanon, as much as thou shalt need: and we will bring it to thee in
floats by sea to Joppa, and thou shalt carry it up to Jerusalem.” These
passages relate to a compact between Solomon and Hiram, king of Tyre,
by which the latter was to cause cedars for the building of the Temple
to be cut down on the western side of Mount Lebanon, above Tripoli, and
to be floated to Jaffa or Joppa, probably along by the sea shore.
The Romans transported by water both timber for building and fire-wood.
When, during their wars against the Germans, they became acquainted
with the qualities of the common larch, they caused large
quantities of it to be carried on the river Po, to Ravenna, from the
Alps, particularly the Rhætian, and to be conveyed also to Rome, for
their most important buildings. Vitruvius says, that this timber was so
heavy that the waters could not support it, and that it was necessary
to carry it in ships or on rafts. Could it have been brought to Rome
conveniently, says he, it might have been used with great advantage in
building. It has also been supposed that the Romans procured fire-wood
from Africa, and that it was brought partly in ships and partly on
rafts.
But it is in Germany that the transportation of timber by means of
floats has been most extensively carried on, partly on account of
its noble forests, and partly through the possession of the river
Rhine. There is evidence of the floating of timber-rafts in Germany so
far back as the year 1410. A letter from the Landgrave of Thuringia
says, that on account of the scarcity of wood that existed in their
territory, the landgraves had so far lessened the toll usually paid
on the river Sale as far as Weissenfels, that a Rhenish florin only[Pg 79]
was demanded for floats brought on that river to Jena, and two
Rhenish stivers for those carried to Weissenfels; but the proprietors
of the floats were bound to be answerable for any injury occasioned to
the bridges.
In 1438, Hans Munzer, an opulent citizen of Freyberg, with the
assistance of the then burgomasters, put a float of wood upon the river
Mulda, which runs past the city, in order that it might be conveyed
thither for the use of the inhabitants: this seems to imply that
such a practice was not then uncommon. When the town of Aschersleben
was adorned with a new church, in 1495, the timber used for its
construction was transported on the Elbe, from Dresden to Acken, and
from thence on the Achse to the place of its destination. In the year
1561, there was a float-master in Saxony, who was obliged to give
security to the amount of four hundred florins; so that at that time
the business of floating must have been of considerable importance.
When the citizens of Paris had used all the timber growing near the
city, the enormous expense of land carriage led to the suggestion of
an improved mode of transport. John Rouvel, a citizen and merchant,
in the year 1549, proposed to transport timber, bound together, along
rivers which were not navigable for large vessels. With this view he
made choice of the forests in the woody district of Morvant, which
belonged to the government of Nivernois; and as several small streams
and rivulets had their sources there, he endeavoured to convey into
them as much water as possible. This great undertaking, at first
laughed at, was completed by his successor, René Arnoul, in 1566. The
wood was thrown into the water in single trunks, and suffered to be
driven in that manner by the current to Crevant, a small town on the
river Yonne; where each timber-merchant drew out his own, which he
had previously marked, and after it was dry, formed it into floats
that were transported from the Yonne to the Seine, and thence to the
capital. By this method large quantities of timber were conveyed to the
populous towns.
A similar mode of transporting timber from the central parts of Germany
to the great towns or to the seaports is practised at the present day.
Planché, in his , says: “Below this
bridge, (at Plattling on the Danube,) the raft-masters of Munich, who
leave that city every Monday for Vienna, unite their rafts before they
enter the Danube. They descend the Isar upon single rafts only; but
upon reaching this point, they lash them together in pairs, and in
fleets of three, four, or six pairs, they set out for Vienna. A voyage
is made pleasantly enough upon these floating islands, as they have
all the agrémens, without the[Pg 80] confinement of a boat. A very
respectable promenade can be made from one end to the other, and two or
three huts erected upon them afford shelter in bad weather, and repose
at night.”
But the anonymous author of gives a
more detailed account of the timber-rafts of Germany, of which we will
avail ourselves. A little below Andernach, on the banks of the Rhine,
the small village of Namedy appears on the left bank, under a wooded
mountain. The Rhine here forms a little bay, where the pilots are
accustomed to unite together the lesser rafts of timber, floated down
the tributary rivers into the Rhine, and to construct enormous floats,
which are navigated to Dordrecht and sold. These machines have the
appearance of a floating village, composed of twelve or fifteen huts,
on a large platform of oak and deal timber. They are frequently eight
or nine hundred feet long, and sixty or seventy in breadth. The rowers
and workmen sometimes amount to seven or eight hundred, superintended
by pilots and a proprietor, whose habitation is superior in size and
elegance to the rest. The raft is composed of several layers of trees,
placed one on the other, and tied together. A large raft draws not less
than six or seven feet water. Several smaller ones are attached to it,
by way of protection, besides a string of boats, loaded with anchors
and cables, and used for the purpose of sounding the river, and going
on shore. The domestic economy of an East Indiaman is hardly more
complete. Poultry, pigs, and other animals, are to be found on board,
and several butchers are attached to the suite. A well-supplied boiler
is at work night and day in the kitchen. The dinner hour is announced
by a basket stuck on a pole, at which signal the pilot gives the word
of command, and the workmen run from their quarters to receive their
allowances.
The consumption of provisions in the voyage to Holland is almost
incredible, sometimes amounting to forty or fifty thousand pounds of
bread, eighteen or twenty thousand pounds of fresh meat, a considerable
quantity of salt meat, and butter, vegetables, &c., in proportion. The
expenses are so great, that a capital of three or four hundred thousand
florins is considered necessary to undertake a raft. Their navigation
is a matter of considerable skill, owing to the abrupt windings, the
rocks and shallows of the river; and some years ago the secret was
thought to be monopolized by a boatman of Rudesheim and his son.
The timber of the spruce firs which grow on the sides of the Alps, is
considered much finer than that which is produced in other situations;
but the inaccessible nature of these[Pg 81] Alpine forests long prevented
those useful trees from being sent in any great quantity to the market.
During our long continental war, however, a bold and skilful plan was
invented, by which this timber was procured in abundance. M. Rupp, an
enterprising foreigner, constructed an immense inclined plane of wood
on the sides of Mount Pilatus, near the Lake Lucerne; its length was
eight miles and a half. Twenty-five thousand large pine trees were
employed in its construction. These were barked and put together very
ingeniously, without the aid of iron. It occupied one hundred and sixty
workmen during eighteen months, and cost nearly a hundred thousand
francs, or 4250l. sterling. It was completed in the year 1812.
The following description of the slide appeared in a German periodical
shortly after its completion:—“This slide has the form of a trough,
about six foot broad and from three to six foot deep. Its bottom is
formed of three trees, the middle one of which has a groove cut out
in the direction of its length, for receiving small rills of water,
which are conducted into it from various places, for the purpose of
diminishing the friction. The whole of the slide is sustained by about
two thousand supports; and in many places it is attached, in a very
ingenious manner, to the rugged precipices of granite.
“The direction of the slide is sometimes straight, and sometimes
zig-zag, with an inclination of from 10° to 18°. It is often carried
along the sides of hills and the flanks of precipitous rocks, and
sometimes passes over their summits. Occasionally it goes under ground,
and at other times it is conducted over the deep gorges by scaffoldings
one hundred and twenty feet in height.
“The boldness which characterizes this work, the sagacity and skill
displayed in all its arrangements, have excited the wonder of every
person who has seen it. Before any step could be taken in its erection,
it was necessary to cut several thousand trees to obtain a passage
through the impenetrable thickets. All these difficulties, however,
were surmounted, and the engineer had at last the satisfaction of
seeing the trees descend from the mountain with the rapidity of
lightning. The larger pines, which were about a hundred feet long, and
ten inches thick at their smaller extremity, ran through the space of
three leagues, or nearly nine miles, in two minutes
and a half, and during their descent, they appeared to be only a
few feet in length. The arrangements for this part of the operation
were extremely simple. From the lower end of the slide to the upper
end, where the trees were introduced, workmen were posted at regular
distances, and as soon as everything was ready, the workman at the
lower end[Pg 82] of the slide cried out to the one above him, ‘’
(Let go.) The cry was repeated from one to another, and reached the
top of the slide in three minutes. The workman at the top or
the slide then cried out to the one below him, ‘’ (It
comes), and the tree was instantly launched down the slide, preceded by
the cry which was repeated from post to post. As soon as the tree had
reached the bottom, and plunged into the lake, the cry of
was repeated as before, and a new tree was launched in a similar
manner. By these means a tree descended every five or six minutes,
provided no accident happened to the slide, which sometimes took place,
but which was instantly repaired when it did.
“In order to show the enormous force which the trees acquired from the
great velocity of their descent, M. Rupp made arrangements for causing
some of the trees to spring from the slide. They penetrated by their
thickest extremities no less than from eighteen to twenty-four feet
into the earth; and one of the trees having by accident struck against
another, it instantly cleft it through its whole length, as if it had
been struck by lightning.
“After the trees had descended the slide, they were collected into
rafts upon the lake, and conducted to Lucerne. From thence they
descended the Reuss, then the Aar to near Brugg, afterwards to Waldshut
by the Rhine, then to Basle, and even to the sea when it was necessary.
“It is to be regretted that this magnificent structure no longer
exists, and that scarcely a trace of it is to be seen upon the
flanks of Mount Pilatus. Political circumstances having taken away
the principal source of demand for the timber, and no other market
having been found, the operation of cutting and transporting the trees
necessarily ceased.”[4]
Professor Playfair, who visited this singular work, states, that six
minutes was the usual time occupied in the descent of a tree; but that
in wet weather, it reached the lake in three minutes. He found it quite
impossible to give two successive strokes of his stick to any, even the
largest tree, as it passed him. The logs entered the lake with such
force, that many of them seemed to penetrate its waters to the very
bottom. Much of the timber of Mount Pilatus was thus brought to market;
but the expense attending the process rendered it impossible for the
speculator to undersell the Baltic merchant, when peace had opened a
market for his timber, and so the Slide of Alpnach fell to ruin.
[Pg 83]
Cutting the Norway Deals.
When the timber is squared before it is exported, it is effected by saw-mills; the manner of proceeding may be illustrated by the treatment of Norway deals. In some cases, the trees are merely roughly-shaped with the axe; but those which are to be made into deals are floated down the mountain-streams to a spot where many collect together, and where a saw-mill is erected. Clarke thus speaks of one that he visited:—“The remarkable situation of the sawing-mills, by the different cataracts, are among the most extraordinary sights a traveller meets with. The mill here was as rude and picturesque an object as it is possible to imagine; it was built with the unplaned trunks of large fir-trees, as if brought down and heaped together by the force of the river. The saws are fixed in sets parallel to each other, the spaces between them in each set being adapted to the intended thickness for the planks. A whole tree is thus divided into planks, by a simultaneous operation, in the same time that a single plank would be cut by one of the saws. We found that ten planks, each ten feet in length, were sawed in five minutes, one set of saws working through two feet of timber in a single minute.” The deals are afterwards transported by river or canal to seaports.
The Cutting and Transport of Canadian Timber.
The conveyance of timber to market in Canada is a very remarkable
instance of commercial enterprise. While standing in the vast pine
forests the timber-trees are common property: they acquire money-value
only when the axe has been applied to them, and when they have been
brought down to a shipping port.
The words lumber and lumbering, which convey no very
definite idea to us, have in Canada and the United States a large and
important meaning. Lumber is the general name for all kinds
of timber, not only while growing in the form of stately trees, but
after it is cut down, and even after it has been rudely fashioned into
such pieces as may be convenient for shipment. So, in like measure,
lumbering may be taken as a general name for all the operations
whereby the timber is brought into a marketable state; including the
cutting down of the trees; the conveyance to the saw-mills; the sawing
them into boards, planks, joists, and other pieces; the forming them
into rafts: and the navigating of these rafts down the creeks and
rivers to the seaports. All the persons[Pg 84] employed in these operations
are designated lumberers; and they are subdivided into smaller
groups according to the duties they undertake to perform.
As the practice of lumbering has been carried on for a great number of
years, all the forests in the vicinity of seaports have been denuded
of their trees: and the lumberers have therefore to go far inland to
obtain their supply of timber. This occasions one circle of operations
to last an entire year, from summer to summer. As the lumberers who
dwell in the interior frequently carry on some other occupation,
perhaps an agricultural one, they cut down trees in the forest just
as it suits their convenience, during the summer and autumn. These
trees are either hewn and shaped into balks and beams, or divided into
shorter pieces, according as they are to be exported whole, or sawed up
into boards and scantlings for the American or Canadian markets.
When a large supply of timber has been thus cut down, and the winter
is so far advanced that snow lies on the ground, preparations are made
for conveying the timber to some stream or river which flows down to
a commercial port. On the banks of such streams saw-mills worked by
water-power are erected, and these are employed for cutting up such of
the “lumber” as is to be sold in the form of planks. The conveyance
to the saw-mills and the operation of sawing occupy together the
entire winter season. When snow is on the ground, a stout pair of oxen
can drag a log from the forest to the saw-mill; and this method of
transport is almost universally adopted, very few horses being employed
in this way. Sometimes the saw-mills are constructed in a small creek
near the forest, but in other cases they are lower down, on the banks
of larger streams; and in this latter case the logs are floated down
the smaller streams till they arrive at the larger one, where a dam
or barrier is placed across the stream to prevent them from floating
beyond the precincts of the saw-mill. The saws are circular in shape.
Many of the mills have but one saw in operation; others have groups
of parallel saws capable of cutting the log into eight or ten planks
at once. Some of the smaller mills are built in so rude and rough a
manner, that their cost does not exceed 30l. or 40l.; but
if the mill lasts as long as the supply of timber in the neighbourhood,
that is deemed sufficient, and a new mill is built when it is found
advantageous to shift the quarters farther inland. A small mill with
one saw, worked for twenty-four hours, will cut up three or four
thousand superficial feet of timber. Men are employed to roll the logs
along the gangways to a platform, and place them in a proper position
to be acted on by the saw.
[Pg 85]
During the season of these operations the rivers and streams are frozen
up; but in spring, when the melting of the ice renders them navigable,
preparations are made for transporting the timber from the mills to
the shipping ports. If the mill be on the banks of a small stream, the
lumberers make up the logs and planks into rafts, the dimensions of
which are suited to the capacity of the stream, and when these reach
a larger stream into which the smaller one empties itself, the small
rafts are broken up and re-arranged into larger ones; but if the mill
be on the banks of the larger stream, the timber is at once made up
into the rafts which float down to the shipping port—three or four
hundred thousand feet of timber being sometimes conveyed in one raft.
Sometimes the streams are too small to admit the rafts to float down
them: and in such case they often lie aground for months, until an
accidental flooding increases the body of water; or else they have to
be broken up altogether, and other means adopted for conveying them
to market. The rafts are generally put together very slightly, the
value of labour being high, and the lumberers regulating the strength
of the raft only in proportion to the distance which it has to float.
This distance may vary from fifty to three or four hundred miles.
Some one of the lumberers who may happen to be best acquainted with
the stream acts as pilot, all the others following his directions in
the navigation. The raft moves just as fast as the stream will convey
it, be it slow or quick, no acceleration of speed being attempted
by sails or oars; so that the time which elapses before the raft
reaches its destination depends on many different circumstances. In
some instances, where all the circumstances are favourable, the pilot
navigates his cumbrous raft night and day without stopping; but if
there are difficulties, he directs it into some cove or sheltered place
during the night. The men are provided with long poles, by which they
can regulate the position of the raft in the stream, keeping it either
in the middle of the current or near the bank. The men seldom trouble
themselves to make huts or cabins on the rafts: for the weather being
spring, and it being optional to them to go on shore when they please,
they make very few arrangements for their trip except in provisions.
On the Lawrence, however, where the French Canadians bring down
timber-rafts to Quebec for shipment, the men erect small huts or
temporary dwellings on the rafts, since the voyage becomes of a more
serious character.
When the rafts reach their destination, the lumber is sold, and the
men share the proceeds according to the nature of their stake in the
enterprise. This share is one entire year’s[Pg 86] earnings, and the final
disposal of the timber is therefore a matter of importance. The men
then set out on foot to return to the interior, and as the distance
they have to travel is sometimes three or four hundred miles, and
the summer warmth has arrived, the journey is generally a fatiguing
one. The men are not all fellow-labourers in an equal degree, for—as
in almost every other kind of commercial enterprise—there must be
some one to act as a capitalist, to feed the labourers while they are
employed, or others who will supply necessaries in advance. There are
storekeepers who purchase an annual supply of provisions, clothing,
implements, &c., and retail them out to the lumberers on credit, to
be paid for when the sales are effected in the spring, and when the
mill-owner has been enabled to pay the wages of the men who felled,
transported, and sawed the timber. If any unforeseen accident prevents
the raft from reaching the shipping port in a saleable state, or if any
other mishap occurs, the whole community share the loss.
The lumberers are among the roughest and rudest of the Canadian and
American population: for their occupation takes them so little among
the haunts of commercial or cultivated men, that they are only a few
shades superior to the American Indians—in some points far beneath
them.
Miscellaneous kinds of Timber.
Deal so completely takes precedence of all other timber in
house-building, that a very slight notice of other varieties will
suffice.
Beech is partially employed in ship-building for the keel and
timbers near it; but it is not at all employed, in civil architecture.
The principal use made of this wood is in the construction of machines,
mill-work, lock-gates, &c., and for handles to tools; it is also a good
wood for the turner, being of a close grain. It will not, however, bear
alternations of moisture and dryness, and is liable to be attacked by
worms, so that it is not extensively employed.
Chestnut belongs to the same tribe as the beech, but although
a valuable wood, it is now little, if ever, used. Formerly it was
extensively so, and the roofs of several ancient buildings were
constructed of it. From some experiments, indeed, it seems to be as
durable as oak itself.
Ash is the wood for the wheelwright and the maker of
agricultural implements; it is one of the most valuable of all timber
trees, combining great strength with elasticity and lightness; it,
however, splits easily. Ash is not used either by the shipwright or the
common carpenter.
[Pg 87]
Elm is a coarse-grained wood, but strong and durable, it does
not work readily, and is therefore but little used. It is, however,
employed for certain parts of ships, and for making casks, chests,
coffins, posts for mill-work, and a few other purposes.
Next to oak and fir, the foreign wood Mahogany is by far the
most valuable, and that most extensively used; it is the growth of
the West Indies and South America, and the tree, the , is, perhaps, the most majestic of all timber trees from
the enormous dimensions to which its trunk attains, its vast height
and size, and its dark beautiful foliage. The mahogany of the island
of Cuba, and that from the bay of Honduras, is first in estimation.
There are two East Indian species, but they are not imported in any
quantities into this country.
The best mahogany is that which grows in dry, cold, and exposed
situations. Such wood is fine-grained, hard, and dark in colour,
richly variegated, causing it from its beauty to rank among the most
ornamental of fancy woods, while the light, coarse-grained wood, which
grows in warm moist climates, is sufficiently abundant to be used for
ordinary purposes, and yet possesses admirable properties for all,
where no great strength or tenacity is wanted.
Within the last twenty years the use of this wood has increased
amazingly, and some ships have many of their upper timbers above the
water-line constructed of Honduras mahogany. Its use in furniture and
cabinet-making is well known, and, indeed, it may be said to be the
principal wood used for this purpose, and to have entirely supplanted
our own walnut, which was formerly in universal use for the same
purposes.
The woods above enumerated are those most extensively or largely used
by the carpenter; but there are several others employed for small
articles, and for particular purposes, which deserve mentioning.
Box is the wood of the , a hardy
evergreen plant, indigenous in all the southern parts of Europe
and Western Asia, and long domesticated in our shrubberies. Box is
especially the wood for turning, it being closer-grained, denser, and
tougher than perhaps all others, except iron-wood, , and one or two rarer woods. Box is used for rules, scales,
and for small cabinet works; but that which gives it particular
importance is its universal use for wood-engraving.
Lance is the name given to the wood of the , a tree indigenous to Jamaica, and one of the most
important that are so, from the valuable qualities of its timber,[Pg 88]
lance-wood far exceeding our ash in lightness, strength, and
elasticity; hence it is admirably calculated for shafts to carriages,
handles to spears, and for all purposes where straight, light,
flexible, and tough wood is required. It is neither so close-grained
nor so hard as box, but it turns well, and does not split; in colour,
it is lighter than box.
Ebony is the name given to the wood of several different trees,
which agree in being dark-coloured, dense, and durable; it is used for
inlaying and for making rules or scales, as not being liable to warp.
It is an excellent wood for turning; but, except for these purposes,
it is less in request now than formerly, when it was much used in
cabinet-making.
is the wood of the , a
large tree indigenous in the West Indies. This wood is the hardest and
heaviest known, and can only be worked in the lathe. It is much used
for making the sheaves, or pulleys of blocks used in shipping,
and for friction-rollers, &c.
There are various foreign woods which, from their beautiful grain and
varied tints, are used in cabinet-making. But as these woods are too
valuable to be used solid, they are sawed into thin leaves, called
veneers, which are glued down on a backing of ordinary mahogany.
The principal of these fancy woods are—
Rose-wood, which is produced by a tree a native of Brazil. This
wood is much used for furniture, both as a veneer, and solid for legs
of tables, chairs, &c.
King-wood is also the produce of Brazil; it is a dark chocolate
wood, veined with fine black veins.
Beef-wood comes from New Holland; is of a pale-red even tint,
and intensely hard and heavy. It is used for inlaying and bordering.
Tulip-wood is a wood of a clouded red and yellow colour, and
very hard, and used for bordering to larger woods. The tree is unknown
to our botanists.
Zebra-wood is a large-sized tree, and abundant enough to be used
as a veneer in large furniture, like rose-wood: it is more curious than
elegant.
Satin-wood is well known for its glossy yellowish tint, from
which it derives its name; there are two varieties.
Maple, from our own indigenous tree, is a very elegant wood,
of a light colour, or else, near the root, variegated with knots and
twisted grain. It is much used in fancy work.
FOOTNOTES:
[Pg 89]
[4] The Mines of Bolanos, in Mexico, are supplied with timber from
the adjacent mountains by a slide similar to that of Alpnach. It was
constructed by M. Floresi, a gentleman well acquainted with Switzerland.
Chapter VI.
THE WOOD-WORK. CARPENTRY.
Having thus briefly noticed the principal kinds of timber, and some of the modes of bringing it to market, we have in the present chapter to trace the wood through the various processes whereby it becomes part and parcel of a house.
Sawing Timber.
When a timber-tree is felled, the branches, arms, and boughs, are cut
off, and the bark stripped, this being valuable for many purposes.
The trunk is then sawed square, and again cut into planks,
deals, battens, &c., as the different-sized boards into
which it is reduced are called.
Teak and mahogany are imported into this country in logs,
distinguished from the long beams known technically as timber,
by their width and thickness being considerable in proportion to their
length.
Timber is sawed in countries producing, or using it, in great
quantities in saw-mills, in which the tools are worked by water or
steam, as described in the last chapter; and it is also sawed into
battens, laths, &c., by circular saws, turned by machinery, like a
lathe; but when timber is sawed by hand, it is done by two men acting
in concert in the following manner:—A pit is generally chosen, round
the margin of which a stout frame is laid. The beam to be sawed is
laid along the centre of this frame, in the direction of the length of
the pit. One man stands on the beam while another is in the pit below
him, and each alternately raises or pulls down a large vertical saw,
with which the beam is cut lengthwise into planks. Wedges of wood are
placed in the fissure as the work proceeds, to keep the cut open, and
thus allow the saw to play freely. This is very hard labour, especially
to the upper man, who has not only to raise the weight of the saw in
the up-stroke, but to guide it correctly along the chalked line on the
beam. This man gets higher wages, and is called the top-sawyer,
a term technically given in jest to any one who is, or fancies himself,
of superior importance.
Scarfing or Joining Timber.
When timber is wanted in lengths exceeding those that can be procured
from the tree in one piece, it must be joined by what is called
scarfing; that is, the ends of the two lengths[Pg 90] that are to be
united into one, are cut so that a portion of the one may lap over and
fit into a portion of the other, which is cut so as to receive it. The
timber, when united, is thus of the same uniform size. The joined ends
are secured together by bolts or spikes. The following figures show the
more usual modes of scarfing timber for different purposes.
The last is a mode of scarfing invented by Roberts, of the Royal
Dock Yards.
Trussing or Strengthening.
When a beam of timber is long in proportion to its breadth and
thickness, it will bend by its own weight, and will be[Pg 91] incapable
of supporting much additional load; it may be strengthened by
trussing, in different modes, of which we will only describe
that usually adopted for girders, intended for floors. The beam is
sawed longitudinally into two equal beams, each, of course, half the
thickness of the original: these halves are reversed, end for end,
so that if there were any weak part in the original beam, this may
be divided equally between the ends of the compound beam made up of
the two halves when bolted together. A flat truss, usually of
oak, with iron king-bolts and abutting plates, resembling in
form and principle a timber roof or bridge, is placed between the
two half beams, and let into a shallow groove cut in each half to
receive it; the compound beam, with this truss in the middle, is then
bolted together again by means of iron bolts, with washers and nuts,
and consequently becomes rigid by the construction of the truss. The
truss is not entirely let into the double beam, as the full effect of
strength may be obtained without the necessity for cutting the groove
in each half beam of half the thickness of the oak truss; consequently,
when the girder is completed, there is a slit all along it, through
which the truss is seen lying in its place between the two sides.
Iron trusses are often used instead of oak, and beams are frequently
strengthened by screwing a thin flat iron truss on one or both sides,
let into the beam for about half the thickness of the metal.
This mode of strengthening a beam by trussing is only adopted in
floors, where it is necessary to limit the depth of the truss to
that of the beam, to obtain a level surface by means of joists laid
across, and supported by, the beam. But it is obvious that much greater
strength may be imparted to a[Pg 92] long beam by making it the base of a
triangular frame, as is done in roofs, in various manners, when the
slanting sides of the triangular frame carry the battens or laths for
supporting the tiles or other covering.
The annexed is the simplest form of a roof, and will help to explain
the subject of carpentry in other respects. The beam A,
called the tie-beam, is of such a length as to rest on the side
walls of the house at each of its ends, and is supposed to be of such
dimensions in depth and thickness as would render it inadequate to
support much more than its own weight. The two sloping rafters B
B, are called principals; they are mortised into
the tie-beam at their ends by a joint, shown in the lower figure, by
which they are provided with a firm abutment, to prevent the ends from
slipping outwards; and in order to prevent the principal from starting
upwards out of the mortise, it is strapped down to the tie-beam by an
iron strap, bolted or screwed to both timbers.
P is termed a king-post, and is cut out with a head and
foot, the former to receive the upper ends of the principals, which,
being cut square, abut firmly against the sloping face of the head. The
sloping principals hold up the king-post, and the tie-beam is supported
from the latter by a stirrup-shaped strap, that goes under the beam,
and is bolted, or screwed, to the post on each side. To prevent the
principals from bending by the strain, or by the weight of the roof
covering, the struts C C, are placed, abutting against the
bevelled part of the foot of the king-post, and are strapped to the
principals, or mortised into them.
The number of tie-beams, with their trusses, &c., of course depends on
the length of the roof, or the material with which it is to be covered.
A longitudinal scantling, or thin beam, called a purline,
E, is laid lengthwise, resting on the principals over the
ends of the struts, and is secured to the former by a spike, or else
by being notched down on to the principal.[Pg 93] These purlines support
the common rafters R, which abut at their feet against a
longitudinal scantling S, lying on, and halved down on,
the tie-beams; at their upper ends, the rafters R rest against
a ridge-piece, or thin plank, let edgeways into the head of the
king-post. The rafters are placed about a foot apart, and on to them
are nailed the laths or battens to carry the tiles or slates.
The Mortise and other Joints.
In constructing roofs, floors, and other structures of timber, the
various beams are framed, or fastened together, by certain
processes calculated to insure strength and permanence in the framing,
which ought to be understood, and their names remembered.
The Mortise and Tenon joint is used when one beam is
to be attached to, and supported by, another, without resting on it,
but so that the beams may be in the same plane. The mortise is a hole
cut into, or through, the side of the one beam, into which hole the
end of the other, cut down to fit the form of the hole, is inserted
and fastened. It is obviously necessary to consider two things in
determining the size and form of the mortise and tenon. First, that by
the former the one beam may not be too much weakened, and yet that it
should be large enough to give the tenon that fits into it, sufficient
strength to enable the beam to carry the weight intended.
[Pg 94]
If the one beam is horizontal, and the other to stand perpendicularly
upon it, the tenon need only be large enough to retain the upright
beam in its place. The foregoing figures are the most usual forms of
mortises and tenons, and will explain their use and principle.
It is obvious that two mortises never should come opposite each other
on the two sides of the same beam.
When the tenon comes through the beam, it is secured from drawing by a
pin or peg put through it.
The Dovetail is used to secure one beam into another, when
they have to resist any strain acting so as to draw them asunder,
rather than to carry any weight; it is consequently employed to frame
wall-plates, or the timber laid in walls to carry the ends of beams
of floors, roofs, and so on, which plates tend to bind the walls
together as well as to receive the ends of the beams. The term is
derived from the end of one beam being cut into a shape resembling
the spreading tail of a bird, which is pinned down in a corresponding
wedge-shaped recess cut in the other beam to receive it. It is clear
from this construction that no force, acting in the direction of its
length, could pull the first beam out of the second without breaking
off the dovetail, which the tenacity of wood-fibre renders nearly
impracticable in one of any size. The dovetail is extensively used in
all cabinet-making, and may be seen in almost any mahogany or deal-box.
When two beams of equal thickness are required to cross one another and
to lie in the same plane, they are halved together; that is,
a notch is cut in each of half the thickness[Pg 95] of the other, then the
uncut part of each lies in the notch of the other respectively, and the
two are pinned together.
Distinction between Carpentry and Joinery.
The smaller and better kind of work executed by the carpenter is called
Joiner’s work, such as the making of doors, windows, stairs,
wainscotting, boxes, tables, &c. &c., which are usually formed of
yellow or Norway deals, wainscot, or mahogany.
When a large surface is to be of wood, it is not formed of planks fixed
together side by side till the requisite width is attained, but it is
formed of framing and panelling. A frame-work of the area
required to be covered, is formed of narrow planks, with cross-bars
between to strengthen the frame; these are called stiles and
rails, according to the directions in which they run, the
former name being given to the upright planks of the frame, while the
horizontal ones are called rails.
The rails are mortised into the stiles, and the tenons, since they must
be comparatively thin, are made proportionably wide, nearly as wide
as the rail. The tenons are always pinned into the mortise holes by
one or two wooden pins driven quite through the stiles and through the
inclosed tenon.
The edges of the stiles and rails are ploughed, that is, a
rectangular furrow is cut in the edge by means of a plane, to receive
the ends and sides of the panels. These panels are formed of
thinner deals than the stiles and rails, and are made by glueing the
edges of two or more boards together to make the proper width of the
panel; the ends and edges of the panel are thinned off to fit into the
groove or furrow in the stiles and rails, or else the ends and sides of
the panel are rebated, that is, worked by a plane into the form
shown in the following figure, the projecting part being received into
the furrow.
As the panels are thinner than the frame, the former constitute so many
recesses, at least on one side of the framing; and a small moulding is
glued round the edge of the panel to form a finish to the work. Or else
the same object is attained by working the edge of the stiles and rails
with such a moulding, so that when the panel is put in, the moulding
may finish against it. Sometimes the face of the panel is made to lie
in the same plane with the face of the stiles and rails, and the panel
is then said to be flush, and the edges of[Pg 96] the stiles, &c., are
finished with a small bead, also flush with the panel when finished.
In joiner’s work the whole surface of the work is made perfectly smooth
by planing the material, and allowance must be made for the
reduction in thickness and width of the wood, produced by this planing,
in the choice of the rough material.
The Tools employed.
All mouldings in wood are worked out by planes made of the proper
form, to leave the moulding in the wood when the plane has been passed
over the part. The carpenter and joiner consequently require a vast
variety of planes for these purposes, which constitutes the most
expensive part of the expensive tools used by these workmen. These
planes receive their names from the form they are intended to produce
in the wood, such as rebating planes, O G planes, ovolo-planes,
beading-planes, and so on.
The next most important tools used by both carpenter and joiner, are
saws, of different sizes, for reducing the rough wood to the
size adapted for the purpose to which it is to be applied. Small,
fine-toothed saws, both long and thin blades, termed spring-saws,
are used for cutting out small holes in wood, and for analogous
purposes, when precision and nicety[Pg 97] are required; these spring-saws
are sometimes mounted in a frame on the same principle as that of the
stone-mason’s saw, formerly described; but commonly, the blade of the
saw, of whatever size it may be, is only fixed on a convenient handle,
so that the whole blade of the saw may pass through the fissure it
makes in the material. All saws are made of the best steel, highly
tempered, so as to recover their form if bent by the resistance of the
wood.
Next to the planes and saws, chisels are the most indispensable
tool to the carpenter. These chisels are of different widths,
adapted to different uses, and are not only used with a hammer or
mallet, as the mason employs them, but also as cutting-tools, used by
hand for finishing the re-entering angles of mortise-holes, or for
finishing the ends of pieces of wood too small to be planed.
The carpenter employs gimlets for making holes for screws and
nails. The gimlet is a short rod of steel, finished at one end into
a sharp-pointed screw of one or two turns only, which, acting on the
principle of that mechanical power, compels the tool to sink deeper and
deeper into the wood, as the tool is turned round: and to enable the
workman to turn the gimlet, it is fixed into a cross handle, which,
acting as a lever, allows the friction of the tool to be overcome. Just
above the screw point, the rod or shaft of the gimlet is fluted
or hollowed out: the sharp edges of this fluted part cut the hole made
by the screw end larger and smoother, and the hollow receives the chips
or shavings cut off, and prevents them from clogging the hole and
stopping the progress of the tool.
Augers are large tools shaped like a gimlet, and, acting in the
same manner, are employed for making large holes for bolts, spikes, &c.
Centre-bits are steel tools of different shapes made to fit into
a bent handle something like the letter G, which, acting as a lever,
allows of the tool being turned round and round by one hand, while by
the other the workman holds the top of the handle steady and vertically
over the point of the tool. Some of the bits or tools are for
cutting out cylindrical holes, and are shaped at the cutting-edge like
a chisel, with a small point projecting from the centre of the edge,
on which the instrument turns in the wood and acts on the principle
of a lathe. On each side this point, the chisel-edge is bent sideways
in opposite directions, to allow of its ploughing up the wood
before it with greater efficacy than it would do if it were not so
formed.
The brad-awl, or nail-piercer, is a short steel wire,
sharpened at the point into a flat chisel-edge, and put into a[Pg 98] plain
turned handle. This edge being pushed into the wood, and the handle
turned round, the tool divides the fibre, and makes its way on the
simple principle of a wedge, and does not cut away or remove any
portion of the material, as the above-described tools do.
The carpenter uses nails and screws to fasten the different parts of
his work together, and it is necessary to make a hole to receive them
before they are driven in, or else the wood would split by the action
of forcing the nail or screw into the solid material, and, indeed, it
would be impossible to force a screw into the solid wood at all.
The screw is forced into the wood by being turned round and round by
means of a blunt chisel, called a screw-driver, the edge of
which is inserted into a notch cut in the head of the screw to receive
it.
The Glue employed.
Joiners fasten one piece of their work to another by glue, made
by boiling down refuse animal matter containing the animal principle
called gelatine in abundance, such as hoofs, horns, tendons,
skin, gristle, &c.: it is a property of gelatine to dissolve in hot
water, and to harden again when cold, and the water evaporates.
Accordingly the glue, which is only concentrated impure gelatine, is
dissolved by heat in a small quantity of water, and being applied
to the clean faces of the wood to be united, by a coarse brush,
these faces are closely pressed and retained together till the water
evaporates, when such is the tenacity of the glue, that the wood may
be broken in another place as easily as at the glued joint. To enable
glue, however, to act in this manner well, the wood should be clean,
the parts to be glued well warmed before the glue is applied, and the
joint should be close, or the parts accurately brought together.
Besides the before-mentioned tools and materials, and some others,
such as hammers, axes, &c., which need not be described, carpenters
and joiners use instruments for measuring and setting out their work,
and for drawing on the surface of the material the forms into which
it is to be reduced, or the shape and situations of portions of the
material to be removed for the purposes of framing. The instruments are
compasses, squares, rules, levels, plumb-lines, and so on, common to
all artificers who form their materials into geometrical shapes: and,
like the mason, the carpenter and joiner must be conversant with the
more elementary problems of practical geometry.
[Pg 99]
A Window-sash, as an example of Joiner’s Work.
In illustration of the nature of joiner’s work, we may point out the
mode of proceeding in making a window-sash, which is one of the most
delicate operations of the common joiner. The outer part of the sash
is made broader and stronger than the intermediate cross-bars which
receive the panes of glass, in order to give strength and rigidity
to the sash. This outer part is framed together at the four angles
by mortises and tenons, the latter coming quite through the stuff,
and having a small sharp wedge driven into the middle of the tenon
when inserted into the mortise: by means of this wedge, the tenon is
expanded at its end into a wedge-shaped form, by which it fits more
tightly into the mortise, and is retained in its place, the wedge-shape
not allowing the tenon to be withdrawn again. But it may be here
remarked, that, besides this precaution, all small mortises and tenons
are put together with glue, to ensure the stability of the joint.
The inner edge of this frame is formed by a plane into the half
moulding, of which the cross-bars present the entire section, so that
when the sash is completed, each panel, as it were, which is filled in
with the glass, is surrounded on its sides by a continuous moulding,
and on the other side of the frame each panel presents a rebate
in which the glass lies. The annexed figure of the section of part of
the outer frame and one cross-bar, will make this clear.
The cross-bars are made in lengths out of slips of wood, by a plane,
which first forms the mouldings and rebate on one side, and then by
turning the slip over, the same plane finishes the other with an exact
counterpart of the first. These bars are framed into the outer part of
the sash by delicate mortises and tenons put together in the manner
before described; but it will be seen by reference to the figure,[Pg 100] that
the moulded part of the bar must unite to that of the outer frame, or
of another bar, by a mitre-joint, that is, by one which allows
of the lines of mouldings returning on the second piece, at right
angles to their direction on the first, without any interruption to the
continuity of the surface.
This and all analogous mitre-joints are formed by planing the ends
of the wood to form a face, making an angle of 45° with the axis or
length of the stuff, and the joiner is provided with a tool called a
mitre-box, consisting of a stock or frame, in which the stuff
being put, resting against one another’s surface, guides the plane so
as to cut off the end obliquely at the requisite angle. It is clear
that this mitre must be made on both faces of the bar, and therefore
the two mitre faces form a wedge-shaped termination by meeting at a
right angle, as shown in the last figure. Now, as besides the mitre
end, a tenon is to be left to fit into a mortise in the outer frame, it
is clear that the whole must be a very nice piece of workmanship to be
executed on so small a material as the thin bar of a modern sash.
The bevelled mitred end of the bar is received into a
corresponding-shaped notch cut the depth of the half moulding in the
outer frame to receive it, and at the bottom of this notch is the fine
mortise-hole intended to receive the tenon.
The bars of the sash can, of course, only be made in one length in one
direction, and the cross-bars which divide the long panels, formed by
these continuous bars, into the sizes of the glass, are made of similar
short pieces with mitred ends; but these ends, where they frame into
the long bars, have no tenon, the thinness of the stuff not admitting
of one, since the cross-bars come, end for end, opposite each other, on
the two sides of the upright bars.
It is evident that the long bars must be put together with the outside
frame, or else the tenons could not be inserted into the mortises made
in this last.
A second example of Joiner’s Work.
In further explanation of joiner’s work, we will briefly describe
the mode of making a drawing-board, requiring to be true,
plane, and square. Suppose the board is intended to be
so wide as to require three boards side by side to make it: these
three boards being sawn out of the right length, their edges are
first planed perfectly straight and smooth, so that when any two are
placed side by side, the edges touching, those edges may touch or fit
together accurately for their whole length; this accuracy of joint is
obtained by testing the edge after each time the plane is applied, by a
straight-edge,[Pg 101] or rule, known to be true. There are two modes
of proceeding to make these joints firm: one by dowelling, that
is, by inserting short pieces of hard wood, as oak or wainscot, let for
half their length into a mortise cut in the edges of the boards that
are to fit together; these mortises, being, of course, made opposite
each other, these dowels prevent the boards from rising up or starting
from their places when the work is finished. Instead of short dowels,
a strip, the whole length of the boards, is let into each joint,
half the strip lying in a ploughed groove, made in the middle of the
corresponding edges of the two boards. But, besides those precautions,
the joints are well glued up.
There are two modes by which this board may be strengthened, to prevent
its warping or casting by the drying or shrinking of the
wood. A cross-piece of deal, or better still, of wainscot, is fixed
across the ends of the boards, these ends being double rebated or
tongued, to fit into a groove made in the cross-piece to receive
the tongue; these cross-pieces prevent the long boards from warping,
since the cross-pieces would have no tendency to alter their figure in
the direction of their grain.
If, however, the board be larger, keying is better than this
clamping. Keying consists in attaching two stout cross-pieces at the
back of the boards, the faces of which pieces are worked so as to fit,
and are glued into a dovetail-shaped groove cut across the direction
of the boards at their back to receive the keys, as will be understood
from the annexed sketch.
When the board is made, and the glued joints quite dry, the face is
planed perfectly smooth and level, and the edges made truly square, or
at right angles; if the board be keyed, the back must be planed smooth
before the keys are put in.
The flooring-boards in the better kinds of houses are often
dowelled in the manner above described, and the ends of the
flooring-boards are tongued and grooved to fit together, to prevent the
boards from starting up from the joists and becoming uneven.
Beyond this point, it will be not necessary to trace the operations
of the carpenter and joiner; for the sawing, scarfing, trussing, and
joining large beams for the roof, and the minuter details connected
with the window-sash, will illustrate pretty accurately the general
nature of the whole routine of processes.
[Pg 102]
Chapter VII.
THE FIRE-PLACE.
Perhaps no part of the interior fittings of a house is more associated with ideas of cheerfulness and domestic comfort than the fire-place. Our abundant supply of coal has probably induced Englishmen to prefer the cheerful fire and the “comfortable fire-side” to any other mode of heating the interior of houses. The steps by which we have arrived at the use of modern grates and stoves, and the question how far these are likely to give way to the methods of warming houses by hot air, by hot water, or by steam, will form an interesting matter for our consideration; and we shall be indebted to Arnott’s treatise on Warming and Ventilating, for many illustrative details.
Open Fire-places.
The manner in which rude nations kindle a fire in or near their huts,
is one of the most wasteful arrangements in which fuel can be used.
Houseless savages, because they know no better, and soldiers at
bivouac, because they must make a virtue of necessity, kindle a fire in
the open air, and place themselves near it, benefiting by that portion
of the radiant heat which falls on their bodies; but all the rest of
the heat is wastefully dissipated.
The next step of improvement is, to kindle a fire in a place more or
less inclosed. Under this arrangement, not only will that part of the
radiant heat which falls on the persons be available, but a portion of
the remainder also, which, falling on the walls and warming them, is
partially reflected; and moreover, heat combined with the smoke will be
for a time retained in the place, and thus still further contribute to
the warmth of the interior. By such an arrangement, nearly the whole
of the heat evolved in the combustion is applied to use; but it is
contaminated with the smoke from the fuel. The savages of North America
place fires in the middle of the floor of their huts, and sit around
in the smoke, of which the excess escapes by the one opening in the
hut that serves as a chimney, window, and door. A few of the peasantry
in the remote parts of Ireland and Scotland still place their fires
in the middle of their floors, and leave for the escape of the smoke
only a small opening in the roof, often not directly over the fire. In
Italy and Spain, almost the only fires seen in sitting-rooms are large
dishes of live[Pg 103] charcoal, or braziers, placed in the middle, with the
inmates sitting around, having to breathe the noxious carbonic acid gas
which ascends from the fire and mixes with the air of the room: there
is no chimney, and the windows and doors are the only ventilators. The
method of warming with open fires in the middle of the room was adopted
in some of the English Colleges, and some of the London Inns of Court,
down to a comparatively modern period.
A step further in advance is to have a fire, not only in an inclosed
space as a means of keeping in the heat, but with an aperture over it
to act as a chimney or vent for the smoke. This is the form, under
various modifications, adopted in most English houses; the fire being
kindled in a kind of recess under a chimney. By degrees we have become
accustomed to the adoption of a grate, which keeps the fuel at a
certain height above the ground; but the principle involved is just the
same. In olden times the fire used to be kindled on the hearth under a
huge chimney, or on a very low grate; but the general course of modern
improvement has tended to lessen the size of the chimney, and to raise
the grate higher from the hearth.
The philosophy of a chimney is well explained by Arnott, in his
. He says: “Chimneys quicken the ascent of
hot air, by keeping a long column of it together. A column of two
feet high rises higher, or is pressed up with twice as much force as
a column of one foot, and so, in proportion, for all other lengths;
just as two or more corks strung together and immersed in water, tend
upwards with proportionally more force than a single cork, or as a
long spear of light wood, allowed to ascend perpendicularly from a
great depth in water acquires a velocity which makes it dart above
the surface, while a short piece under the same circumstances rises
very slowly. In a chimney where one foot in height of the column of
hot air is one ounce lighter than the same bulk of the external cold
air, if the chimney be one hundred feet high, the air or smoke in it
is propelled upwards with the force of one hundred ounces. In all
cases, therefore, the draught, as it is called, of a chimney is
proportioned to its length.”
Defects of Open Fires.
This being the general arrangement of a fire in a recess on one side of
the room, and an open chimney above it, Arnott enumerates a long
list of evils and inconveniences consequent on such an arrangement.
1. Waste of fuel.—It has been found that in a common[Pg 104] open
English fire, seven-eighths of the heat produced from the fuel ascend
the chimney, and are absolutely lost. This lost fuel is thus accounted
for. One half of the heat is carried off in the smoke from the burning
mass; one quarter is carried off by the current of the warmed air of
the room, which is constantly entering the chimney between the fire and
the mantel-piece, and mixing with the smoke; lastly, one eighth part of
the combustible matter is supposed to form the black and visible part
of smoke, in an unburned state. Some writers have even gone so far as
to estimate the loss of heat in an open fire at fourteen-fifteenths
of the whole. 2. Unequal heating at different distances from
the fire.—This forms a remarkable contrast with the uniform
temperature in the air of a summer afternoon. In rooms with a strong
fire, in very cold weather, it is not uncommon for persons to complain
of being “scorched” on one side, and “pierced with cold” on the other;
this is particularly the case in large apartments; for as the intensity
of radiating heat (like light) is only one-fourth as great at a double
distance, the walls of the room farthest from the fire are but little
warmed, and, therefore, reflect but little heat to the backs of persons
grouped round the fire. 3. Cold draughts.—Air being constantly
required to feed the fire, and to supply the chimney-draught, the fresh
air which enters by the crevices and defects in the doors, windows,
floors, &c., is often felt most injuriously as a cold current. “There
is nothing more dangerous to health than to sit near such inlets, as is
proved by the rheumatisms, stiff necks, and catarrhs, not to mention
more serious diseases, which so frequently follow the exposure. There
is an old Spanish proverb, thus translated,
If cold wind reach you through a hole,
Go make your will, and mind your soul,
which is scarcely an exaggeration.” The current of fresh air which
enters to feed the fire becomes very remarkable when doors or windows
are opened, for the chimney can take much more than it otherwise
receives when the doors and windows are shut; and thus the room with
its chimney becomes like an open funnel, rapidly discharging its
warmed air. 4. Cold to the feet.—The fresh air which enters
in any case to supply the fire, being colder and specifically heavier
than the general mass already in the room, lies at the bottom of
this as a distinct layer or stratum, demonstrable by a thermometer,
and forming a dangerous cold-bath for the feet of the inmates, often
compelling delicate persons to keep their feet raised out of it by
footstools, or to use unusual covering to protect them. 5. Bad
ventilation.—Notwithstanding the rapid change of air[Pg 105] in the room,
perfect ventilation is not effected. The breath of the inmates does not
tend towards the chimney, but directly to the ceiling; and as it must
therefore again descend to come below the level of the mantel-piece
before it can reach the chimney, the same air may be breathed over
and over again. In a crowded room, with an open fire, the air is for
this reason often highly impure. As another source of impure air in
a house, it may be noticed that the demand of the chimneys, if not
fully supplied by pure air from about the doors and windows, operates
through any other apertures. 6. Smoke and dust.—These are
often unavoidable from an open chimney, much affecting the comfort and
health of the inhabitants of the house, and destroying the furniture.
Householders would make great sacrifices in other respects to be
free from the annoyance of smoke. In large mansions, with many fires
lighted, if the doors and windows fit closely, and sufficiency of air
for so many chimneys cannot therefore enter by them, not only do the
unused chimneys become entrances for air, but often the longest and
most heated of them in use overpower the shorter and less heated, and
cause the shorter chimneys to discharge their smoke into the room. 7.
Loss of time.—During the time every morning while the fires are
being lighted, the rooms cannot be used; and there are, besides, the
annoyances of smell, smoke, dust, and noise, all of which are again
renewed if the fire is allowed to go out and to be relighted in the
course of the day. 8. Danger to person and to property.—How
numerous are the losses of property by carelessness as to fires is well
known to all, while the loss frequent but more distressing loss of life
too well attests the danger to children and to females thinly clad
often consequent on an open fire.
Such are the principal defects which Arnott enumerates as being
inherent in the use of open fires. Many of them have been greatly
lessened by improved arrangements; but others are still without an
appropriate remedy.
The usual construction of a fire-place is tolerably familiar. In most
cases, the vertical or nearly vertical channel for the chimney is
inclosed within a casing of brick-work, which projects into the room at
one side. The opening for this chimney gradually narrows upwards, until
only large enough to admit the poor little climbing-boy whose task
it was, until within a recent period, to sweep down the unburnt fuel
which our own ill arrangements have wasted; but, happily for humanity
and justice, this system is at an end, and machines are now employed
for the purpose. A hearth of stone is laid whereon to erect the stove
or grate, and this grate is, as we all know, composed mainly of an
iron receptacle for the fuel,[Pg 106] and of “hobs,” for supporting culinary
vessels. We cause fire to be kindled in the grate, and then suppose
that all will go on well, without troubling ourselves to inquire
whether the arrangements for the supply of cold air, and the exit of
warmed air and smoke, are such as are best fitted for those purposes.
Remedies for some of these Defects.
In course of time, as the evils of this plan became one by one known,
attempts were made to remedy some of them, and with an approach towards
success. In a recent treatise on the subject by Fyfe, of Edinburgh,
various modes are suggested for remedying many of the evils incident to
open fire-places. These we must briefly notice.
Sometimes the rooms of a new house are subject to the nuisance of smoky
chimneys simply from deficiency of air. The workmanship of the rooms
being all good, the joints of the flooring-boards and of the wainscot
panels are all true and tight, the more so as the walls, perhaps, not
yet thoroughly dry, preserve a dampness in the air of the room, which
keeps the wood-work swelled and close. The doors and the sashes, too,
work closely and correctly, so that there is no passage left open for
the air to enter except the key-hole, and even this is often closed
over by a little brass cover. Thus, air being denied admission into
the room, there is nothing to feed the fire and to cause a “draught,”
and the smoke cannot ascend the chimney. Instances have been known
of well-built houses being rendered almost untenantable from this
cause, and several hundred pounds being spent in endeavouring to
find a remedy. If, on opening the door or window of a smoky room, it
be generally found that the smoke disappears, this may be taken as
an indication that the close-fitting joints of the wood-work do not
admit air enough for the fire when doors and windows are closed. In
such a case, the opening of the door or window is a poor attempt at
a remedy; for the air proceeds direct to the chimney, and in its way
causes cold to the back and feet of those who may be sitting before
the fire. Numerous methods have been devised for admitting additional
air to the rooms without this inconvenience, among which Arnott
recommends tubes leading directly from the outer air to the fire-place,
and provided with what are called “throttle-valves,” for the regulation
of the quantity. The following plan has also been recommended as one of
the most practicable. As the air in the upper part of a room is warmer
than in the lower, it is desirable that the supply should come in that
direction, so as to[Pg 107] be slightly warmed in its progress towards the
fire, and thus produce less chill to those in its immediate vicinity.
This may be done by drawing down the upper sash of the window about an
inch; or, if not moveable, by cutting such a crevice through its frame;
in both which cases, a thin shelf of the length of the opening may be
placed to conceal it, sloping upwards, to direct the air horizontally
along and near the ceiling. In some houses, the air may be admitted in
such a crevice made in the wainscot or cornice near the ceiling, and
over the fire-place; this, if practicable, is the better of the two,
since the cold air in entering will there meet with the warmest rising
air from before the fire, and be soonest tempered by the mixture.
Another contrivance is to take out an upper pane of glass in one of
the sashes, set it in a tin frame, giving it two springing angular
sides, then replacing it, with hinges below, on which it may turn; by
drawing in this pane more or less, the quantity of air admitted may be
regulated, and its position will naturally direct the admitted air up
and along the ceiling. The circular vane or ventilator sometimes fixed
in windows admits cold air in a similar manner, when the supply for the
room and fire would be otherwise deficient.
The opening or breadth and height of the fire-place, though we may
fancy it leads to the diffusion of more heat into the room, is really a
cause of loss of fuel, and of smoke. The size of the fire-place opening
is often considered in relation to the size of the room, without
regard to the principles on which a fire is maintained in a grate; a
course about as rational (it has been well observed) as to proportion
the step in a staircase to the height of the story, instead of to the
convenience of our legs in mounting them. As the chimneys of different
rooms are unavoidably of different heights, and as the force of the
draught is in proportion to the height of chimney filled with warmed
and rarefied air, it is found that the opening for a tall chimney
may be larger than for a lower one. If the opening be unnecessarily
large, there is room not only for the entrance of fresh air, but also
for the exit of smoke driven down by an opposing current from the
chimney itself; and the air, too, ascends into the chimney in too cold
a state, because the largeness of the opening enables it to enter
without passing very close to the fire. The principal evil attending
the use of a fire-place having too small an opening, is that the fuel
is burned away with unnecessary rapidity. When the opening is found
by experience to be so large as to lead to the descent of smoke into
the room, the easiest remedy is to place moveable boards or sheets of
tin or iron, so as to lower and narrow it gradually. The effect of[Pg 108]
which, by excluding a part of the colder air from the chimney, is to
produce a quicker action, so that the fire begins to roar as if blown
by a bellows. “This means is often used to blow the fire instead of
bellows, or to cure a smoky chimney, by increasing the draught. What is
called a register stove is a kindred contrivance. It has a flap
placed in the throat of the chimney, which serves to widen or contract
the passage at pleasure. Because the flap is generally opened only
enough to allow that air to pass which rises directly from the fire,
the chimney receives only very hot air, and therefore acts well. The
register stove often cures smoky chimneys; and by preventing the too
ready escape of the moderately warmed air of the room, of which so much
is wasted by a common fire-place, it also saves fuel.” There does not
appear to have been any attempt to determine by experiment the proper
opening of the fire-place for a given height of chimney; and, indeed,
there are so many disturbing causes, that it would be scarcely possible
to determine this with precision. Franklin, however, proposed to
make the fire-place openings in the lower rooms about thirty inches
square and eighteen inches deep; those in the upper, eighteen inches
square, and not quite so deep; and those in the intermediate rooms, of
dimensions between these two extremes.
In some cases, where other matters are properly attended to,
inconvenience results from the chimney being too low; as, for instance,
in the case of an attic chimney. In this instance the column of heated
and rarified air is not high enough to give a rapid ascensive power
within the chimney, and thus the smoke cannot be carried up. The best
method of cure is to add to the length of chimney, if this can be done,
and if the fire be in a low building near the ground, this may perhaps
be effected; but in an attic, the means of supporting a lofty chimney
would be inefficient. Another recourse is to contract the opening of
the fire-place to the smallest available dimensions, so that all the
entering air may pass through or close to the fire before entering the
chimney, and thus acquire an ascensive power which will counterbalance
the shortness of the vertical column. It has been recommended that in
some cases there may be three chimneys to one room, so that the united
length of the whole may be equal to that of a tall chimney; but it is
not easy to conceive how this can be practically effected, nor how
the desired result would follow, even if the arrangements were made.
In some cases, the chimney of a room is rendered practically shorter
by being bent round and made to enter the chimney of another room;
since, unless there be a fire in this room also, the warm air[Pg 109] from
the shorter chimney has often an adverse current to contend against at
the junction with the other chimney. This is one reason why every open
fire-place should have its own chimney independently of others.
If there be a lofty building or hill near a house, and over-topping
the chimney of one of the rooms, that room is very likely to become
smoky, on account of a current being driven in at the top of the
chimney, and forcing the smoke down with it. Two rival chimneys may
produce a similar effect in a remarkable way. Suppose that there were
two fires in one room, one burning with more force, and therefore
having a more ascensive column of air above it, than the other; if
the doors and windows be shut, the stronger fire will overpower the
weaker, and for its own demand will draw down air from the chimney of
the latter, which air in descending brings down smoke into the room.
The same would be observable in a greater degree if one fire-place had
a fire in it but the other had none, both being at the same time open.
If, instead of being in one room, the chimneys are in two different
rooms communicating by a door, the case is the same whenever that
door is open. In a house where all the openings, such as doors and
windows fitted tightly, a kitchen chimney has been known to overpower
every other chimney in the house, and to draw air and smoke into an
upper room as often as the door communicating with the room was open.
The remedy for this inconvenience lies in the arrangement of the
fire-places, so that each fire shall have exactly enough air for the
consumption of the fuel, without having to borrow from other rooms.
The arrangement of the door of a room influences materially the proper
action of a fire in the fire-place. When the door and chimney are on
the same side of the room, and if the door be in the corner, and is
made to open against the wall, (an arrangement which is often made
for the sake of convenience,) it follows, that when the door is only
partly opened, a current of air rushes along the wall into and across
the opening of the fire-place, and drives some of the smoke out into
the room. This acts more certainly when the door is being closed, for
then the force of the current is augmented, and becomes an annoyance
to persons who may happen to be situated in its path. When the door
and fire-place of a room have been thus ill-arranged with respect to
each other, the evil may be lessened by placing an intervening screen
between the door and the fire, or by reversing the position of the
hinges on the door, so as to make it open in the opposite direction.
Sometimes the smoke from a chimney is driven out into the[Pg 110] room, even
when the chimney is not commanded by a superior elevation, it being
driven down by strong winds passing over the top of the chimney.
Franklin mentioned one or two instances of this kind which he had met
with:—“I once lodged at a house in London, which in a little room
had a single chimney and funnel. The opening was very small, yet it
did not keep in the smoke, and all attempts to have a fire in this
room were fruitless. I could not imagine the reason, till at length
observing that the chamber over it, which had no fire-place in it,
was always filled with smoke when a fire was kindled below, and that
the smoke came through the cracks and crevices of the wainscot, I had
the wainscot taken down, and discovered that the funnel which went up
behind it had a crack many feet in length, and wide enough to admit
my arm; a breach very dangerous with regard to fire, and occasioned
probably by an apparent irregular settling of one side of the house.”
This does not at first thought seem to be an illustration of the effect
of wind passing over the top of a chimney; but the explanation is to be
sought for in a similar way; the air, by entering this fractured part
freely, destroyed the drawing-force of the chimney.
The manner in which the passing of a current of wind over the top of a
chimney may produce a “smoky room” is this:—the warm air which rises
from the fire, in order to obtain a free issue from the chimney, must
repel the air that is hovering over the chimney-pot. In a time of calm
or of little wind, this is done easily; but when a violent current is
passing over the top of the chimney, its particles have such a strong
horizontal velocity, that the heated air in ascending has not power to
displace it, and thus the smoke, not finding a ready exit by that path,
is driven back into the room.
The following anecdote, told by Franklin, will show what accidental
causes will sometimes occasion a fire to fail in its desired office of
yielding heat without smoke:—“Another puzzling case I met with at a
friend’s house near London. His best room had a chimney, in which he
told me he never could have a fire, for all the smoke came out into the
room. I flattered myself I could easily find the cause, and prescribe
the cure. I opened the door, and perceived it was not want of air. I
made a temporary contraction of the opening of the chimney, and found
that it was not its being too large that made the smoke to issue.
I went out and looked up at the top of the chimney: its funnel was
joined in the same stack with others, some of them shorter, that drew
very well, and I saw nothing to prevent its doing the same. In fine,
after every other examination I could think of, I was obliged to own
the insufficiency of my skill. But my friend, who made[Pg 111] no pretension
to such kind of knowledge, afterwards discovered the cause himself.
He got to the top of the funnel by a ladder, and looking down, found
it filled with twigs and straw, cemented by earth, and lined with
feathers. It seems the house, after being built, had stood empty some
years before he occupied it, and he concluded that some large birds had
taken the advantage of its retired situation to make their nests there.
The rubbish, considerable in quantity, being removed, and the funnel
cleared, the chimney drew well and gave satisfaction.”
From these details it will at once appear, that that part of the
builder’s art which relates to the arrangement and building of the
fire-place is by no means an unimportant one, since the comfort of the
inmates is seriously affected by want of skill on his part. Hence we
may also observe, that chimney doctors are liable to the same kind of
errors as quack doctors in another sphere; for it is almost as absurd
to attempt to cure all smoky chimneys by one course of proceeding,
as to cure all kinds of diseases by one medicine. There may be a
deficiency of air in the room; the opening of the fire-place maybe
too large; the chimney may not have height enough; one chimney may
overpower another in its draught; the chimney may be overtopped by
higher buildings or by a hill; the door of a room may be badly placed
with respect to the window; or, lastly, as in Franklin’s “puzzling
case,” the chimney may be nearly stopped up. All these are sources of
the much-dreaded “smoky chimney,” and all require modes of treatment
adapted to the nature of the evil. Many of these evils have, to a
considerable extent, been remedied by the use of Rumford stoves, and
other forms of stove and grate, in which, although retaining all the
chief characters of an open fire-place, there is yet a great diminution
of the evils to which the latter is liable. There have, however,
been marked extensions recently made in the construction of close
stoves, intended to obviate the ill effects attendant on open
fire-places. These must be briefly noticed.
Close Stoves.
In a close stove, no air is admitted but what passes at once through
the fire; and the chimney or funnel is only just large enough to carry
off the sulphurous and other vapours, for there is hardly any smoke
from a close stove, and, therefore, it is not necessary to make a
chimney large enough to admit a climbing-boy.
A small German stove, suitable for a room twenty-four feet by eighteen,
will give an idea of the general character of this[Pg 112] kind of close
stove. The stove rests on a base about thirty-six inches by fourteen.
The fire-place has a bottom to receive the fuel, but no bars, and is
shut by a door which fits closely to its case. This door has a small
wicket at the bottom, the aperture of which is regulated by a sliding
plate, so as to admit no more air than will suffice for the slow
combustion of the fuel. The flame and heated air ascend to the top of
the fire-place, and pass into two hollow pillars or piers, which rise
to a height of five or six feet, so that the heat is communicated to a
large surface, before the volatilized products of combustion make their
exit by a pipe into the chimney. The stove is supplied with fuel and
with air by the front door. If it is desired to make the fire visible,
and impart some of that cheerfulness which belongs to an open grate,
the door of the stove maybe thrown open, for there is no danger of the
smoke coming out after the current has once warmed the upper part of
the stove. When the stove is of such dimensions that the body of it is
about two feet and a half high, the fire-place may be furnished with
a small grate in the English style. If the door is so hung that it
can not only be thrown back, but also lifted off its hinges, it will
approach still more to the character of a stove-grate.
A cheap form of “German stove” is often made in this country, and used
in workshops and small manufactories, where the body of the stove is
an upright cylinder, of which the lower part is the ash-pit, closed or
opened by a hinged-door, the middle part the fire-place, where the fuel
rests on bars, and the upper part a vacant space, which becomes filled
with flame, smoke, and heated air, so as to impart great heat to a flat
iron plate at the top. There is a door at which the fuel is introduced,
and a small flue or funnel of iron pipe, which conveys the smoke into a
chimney or into the open air. Many forms of stove have been used more
or less resembling this in principle; but there is one great defect
pertaining to them all. The metal of which the stove is formed becomes
so highly heated near the stove, that it acquires a burnt smell,
owing to the decomposition of animal and vegetable particles which are
at all times floating about in the air. The air, too, in the room,
becomes close and oppressive from another cause; for as only a small
quantity of air is consumed by the stove, the air does not become
renewed in the room so frequently as when an open fire is used, and
thus it is respired over and over again.
To remedy the evils resulting from burnt air, close stoves are made
with a double case, so that there shall be a body of air between the
fire and the air of the room. It is on this principle, modified in
various ways, that a large number[Pg 113] of stoves have been constructed;
of which one, by Sylvester, may be briefly described. There is a
hollow cast-iron box, on the outside of which are cast several ribs.
Those ribs are about three-quarters of an inch thick, and project three
or four inches beyond the surface of the box; and their object is to
increase the heating surface; for the fire being lighted in the hollow
of the box, the conducting power of the iron causes the whole exterior
case of the box, together with the projecting ribs, to become heated.
The box is placed within an ornamental case, the sides and top of which
are fretted with lattice-work, to allow free access to the air, which
enters through the lattices at the sides and escapes from the top of
the stove, passing in its passage over the ribbed surface of the heated
box. The grating on which the fuel lies is formed of a number of loose
bars fitted together into a frame, and prolonged so as to emit heat
into the room as well as to support the fuel. Everything is so arranged
as to give as much iron surface as possible, so as to communicate heat
to the surrounding air; while at the same time the extent of the heated
surface prevents any one part from being excessively and injuriously
heated.
Arnott’s Stove.
To describe all the “chunk” stoves, “Vesta” stoves, “Olmsted” stoves,
and other similar contrivances of modern times, would fill a volume
instead of a few pages. We may, however, speak briefly of Arnott’s
stoves as a means of showing some of the inconveniences to which close
stoves are liable, if not constructed with care. This stove consists of
an external case of iron, of any ornamental shape. Within this case is
placed a box made of fire-clay, to contain the fuel, having a grating
at the bottom; and there is a space left between the fire-box and the
exterior case, to prevent the communication of too much heat to the
latter. Thee pedestal of the stove forms the ash-pit; and there is no
communication between the stove and the ash-pit, except through the
grating at the bottom of the fire-box. A small external hole in the
ash-pit, covered by a valve, admits the air to the fire; and according
as this valve is more or less open, the vividness of the combustion is
increased or diminished, and thence the greater or less heat produced
by the stove. The quantity of air admitted by this valve is governed by
a self-regulating apparatus, either by the expansion and contraction
of air confined by mercury in a tube, or by the unequal expansion of
different metals. The smoke escapes through a pipe at the back of the
stove; but the fuel employed is such as to[Pg 114] yield very little smoke.
By adjusting the regulator so as to admit only a small quantity or
air, the temperature of the stove is kept within the required limits;
and owing to the slow-conducting power of the fire-clay, of which the
fire-box is formed, the heat of the fuel is concentrated within the
fire-box, and the fuel burns with less air and less rapidity than it
would otherwise do.
The construction of Arnott’s “thermometer stove” will be better
understood from the following figure, which represents the stove with
one of its sides removed, so as to exhibit its interior arrangements:—
The outlines of the figure, a a a a, represent the case or body
of the stove, which might be formed either of cast or sheet iron. It
is divided into two chambers by the partition, b b; but in such
a way that there may be a free communication at the top and bottom.
c is a small furnace, or, as it is called by the inventor, a
fire-box, made of iron, and lined with fire-bricks. The fire-box is not
in contact with the exterior case of the stove. It communicates at the
bottom with an ash-pit, the door of which is at d,—that of the
stove, by which the fuel is introduced, is at d´. Both these
doors must fit very accurately. Above the door of the ash-pit is a bent
pipe e, by which air gains admittance to the fire.
A fire being kindled and the doors at d d´ shut, the only way in
which air has access to the fuel is by the pipe e; the air so
admitted, passing through the fire before it enters the upper part of
the stove. That portion of the air not required[Pg 115] to aid the combustion
of the fuel having reached the main body of the stove, and there
mixing with the smoke and other products, they circulate slowly in the
directions indicated by the arrows, and at length pass into the chimney
by the pipe f.
The slow movement just mentioned as taking place within the stove may
well be contrasted with what happens in an open fire-place. In one
case the greater part of the heat produced is rapidly carried off by a
current of air ascending the chimney—by the thermometer stove it is
detained until almost the whole of it has been diffused throughout the
apartment.
The bent tube g terminating in a cup-shaped opening at
g´, is a self-regulating valve. The tube is closed at the end
g within the stove, g´ g´´ represents mercury which
occupies the bend of the tube. When the fire in the stove burns too
briskly, the air in the tube occupying the space between g and
g´´ is expanded, and by expelling some of the mercury from the
tube at g´´ into the cup at g´, it closes the aperture of
the pipe e; thus cutting off the supply of air to the fire. In a
few minutes (the fire in the mean time having abated its energy,) the
air in the tube will return to its former dimensions, and the mercury
subsiding in the cup, air is again permitted to enter the ash-pit.
The stove, of which we have thus attempted to convey a general
idea, may be made of any required form or size. Instead of the
self-regulating air-valve just described, it is fitted up with others
of a very simple construction, and which admit of being adjusted with
the greatest accuracy by the hand.
The objections to this form of stove arise chiefly from the formation
of deleterious gases, which are not carried off completely. The slow
combustion of the fuel produces a large quantity of carbonic oxide,
which is liable to escape into the room, and is of an injurious
character. Carburetted hydrogen gas is also formed in these stoves.
Many modifications of form have been suggested for the remedy of these
evils; but the slow combustion, which was one of the merits originally
claimed for the stove, and which it certainly deserves, seems an
unavoidable cause for the production of these gases.
All the varieties of open fire-place, as adopted in English houses, the
hearth, the recess, and the chimney, are at one side or at one corner
of the room; but in the adoption of close stoves this arrangement
is not necessary; for the stove may be in any part of the middle of
a room, provided the pipe constituting the flue be long enough. In
some cases this pipe is carried upwards to the ceiling, and thence
conveyed to[Pg 116] some outlet into the open air; in other cases it is turned
downwards and conveyed under the flooring to a proper place of exit;
while in others the pipe is stretched or extended horizontally from the
stove to the regular chimney of the room.
Warming Buildings by Heated Air.
Our builders have not yet entered so far into the mechanical
contrivances of the age as to dispense with chimneys altogether; nor
could such a thing be done until a total change is effected in the
opinion of persons concerning the cheerfulness of an “open fire.”
But there are nevertheless three modes, more or less adopted in the
present day, whereby a house is warmed without the necessity for
anything like a fire-place. These methods—in all of which the heating
agent is brought from another room into the one to be warmed—are of
three kinds; heating by hot air, by hot water, and by
steam.
When we speak of warming an apartment by heated air, it is necessary
to give precision to the meaning of the term. All rooms are, in fact,
warmed by heated air, for the stove or grate must raise the temperature
of the air in the room before we can appreciate the sensation of
warmth. But what is generally meant by the term as here used is the
warming of one apartment by air heated in another. The stoves used in
Russia, though not coming exactly under this description, will serve in
some degree to illustrate the principle.
The Russian stove is intended as a sort of magazine, in which a great
quantity of heat maybe quickly accumulated, to be afterwards slowly
communicated to the apartment. The stove is therefore made of a massive
size. It is formed of brick-work, clay, glazed tiles, which together
form a great mass of matter to be heated by the fuel; and there is in
every part a considerable thickness of slow-conducting material between
the fuel and the air of the room. The fire is kindled early in the
morning, after which the stove door is shut, and the air aperture below
left open for some time as a means of admitting draught to the fire;
but in the course of a short time the fire-door is opened to check the
draught, so as to prevent the too rapid combustion of the fuel. In
this way the combustion is allowed to go on, and the substance of the
stove becomes warmed, after which the air passages are shut, so as to
prevent any abstraction of heat by the current that would otherwise
be occasioned. The stove thus becomes a great mass of heated matter,
which is gradually pouring warmth into the apartment during the whole
of the day; and as the temperature of the surface never becomes very
high,[Pg 117] the impurities in the atmosphere are not decomposed, and it is
consequently free from those offensive effluvia, unavoidable when metal
stoves are used. The fuel is allowed to be nearly burnt out before
the apertures of the stove are closed; and therein the stove differs
greatly from those hitherto considered; the heated air within the stove
being so completely shut in that it can find no outlet, except through
the substance of the brickwork.
The modifications of the arrangements whereby warmed air is conveyed
from one room to another, may next be noticed. In such cases the air
either escapes from a heated receptacle outside the fire-case, or
else it merely passes over a heated metallic surface. The following
description relates to one variety of the first of these two methods.
In the lower part of a house or building is a cast-metal double stove;
the inner part forming the stove, and the outer one the case or
envelope. The fuel is burned in the inner stove, and the smoke produced
during the process of combustion is carried off by a chimney, which
passes through both stoves or cases, and is conveyed to the outside
of the building. The outer case includes not only the furnace or
inner stove, but also a considerable space occupied by the air of the
atmosphere, which is freely admitted through a number of holes placed
around it; and when any current of warmed air is produced, it passes
off from the space between the outer case and the inner stove, and is
conveyed by tubes to any apartment in the building; so that the rooms
are warmed by the air which has passed between the outer case and the
inner stove.
In another form of arrangement, having the same end in view by means
of heated air, the air, instead of passing through an enclosed space
between the outer case and the inner stove, passes over a surface of
metal which is heated either by a fire underneath, or, which is better,
by steam or hot water contained in pipes. The temporary House of
Commons, the Reform Club-house, and many other buildings, are warmed in
this way.
The following simple and cheap form of stove has been erected in the
cottages of Sir Stewart Monteath’s labourers. The accompanying figure
represents a section of the stove, the principle of which will be
understood from the following explanatory notes:—
[Pg 118]
- Kitchen fire.
- Chimney.
- Hot air Chamber. This is a cast-iron box, which forms the back of the kitchen grate.
- Cold air pipe, or passage; made with brick, or stone, or iron piping, communicating with the open air for the purpose of feeding the hot air chamber with an ascending current of fresh air.
- Hot air pipe, receives the ascending current of air, which becomes heated by passing over the back of the fire. At the top this pipe branches off at right angles, and terminates near the floor in the two sleeping rooms above.
- Gratings to admit the warm air from the hot-air pipe into the bed-rooms. The addition of sliding valves over the face of the gratings would serve to cut off the current of warm air during the summer, and when not otherwise required.
- Sitting-room, into which sufficient heat is radiated from
the hot air chamber, not only to warm the apartment, but even to dry
wet linen.
By means of one common fire in a stove of the above description, a
four-roomed cottage can be comfortably warmed, and kept dry throughout.
Warming Buildings by Steam.
The arrangements for warming rooms and buildings by steam are very different from those in which stoves are employed. They are generally such as the following. At a convenient part of the building, and as low as possible, there is placed a close steam-boiler of the ordinary construction. From this boiler a small steam-pipe is carried to the parts of the building which are to be warmed; the pipe being wrapped round with a thick layer of flannel, to prevent the heat from radiating before it arrives at the destined place. Pipes of a larger size are laid round the rooms above the floor, or under a perforated floor, or in any other convenient position. The steam issues into these larger pipes, from the surface of which heat radiates into the room, and thus the steam is condensed[Pg 119] into water. Small pipes of lead or tin are provided for convoying the water back into the boiler, a gentle slope being given to all the pipes to facilitate this object. This water, again flowing into the boiler, is again converted into steam, again ascends to the pipes which surround the apartment, again gives out heat to the air of those apartments, and again flows back to the boiler in the form of water. Thus the same supply of water circulates over and over again through the pipes, carrying heat from the fire below to the rooms above. In some cases the steam-pipes in the apartments, instead of being laid round the sides, are grouped together in a compact form, and have an ornamental character imparted to them.
Instead of pipes, the steam is sometimes made to circulate between parallel sheets of copper or iron, in such manner that every sheet of metal shall have steam on one side of it, and air on the other, the air in that position receiving heat from the steam through the metal.Warming Buildings by Hot Water.
Lastly we have to notice the method of warming by hot water. In this method there is usually a boiler communicating by an upper and lower pipe, with an upright pipe the same height as the boiler. On the application of heat to the boiler, the column of water becomes lighter than that in the upright pipe; therefore the pressure on the water in the lower pipe being less at the end nearest to the boiler than it is at the other end, a portion of the water in this lower pipe moves forward towards the boiler, which causes a corresponding quantity to pass along the upper pipe in a contrary direction. This motion will necessarily continue as long as the column of water in the boiler is hotter, and therefore lighter than that in the upright pipe; and this must be the case so long as the boiler continues to receive heat from the fire, and the pipes to part with their heat to the air, and thereby cool the water contained in them. In whatever form the hot water apparatus is constructed, this difference of pressure of the two columns of water is the cause of the circulation.
In this form of apparatus some part or other of the water is open to the atmosphere, either at the top of the boiler or at the top of one of the pipes, so that there is no danger from the bursting action of water heated above the boiling temperature. But, on the other hand, the water cannot well be conveyed to rooms at different elevations in the building. To increase the efficacy of the arrangement in this respect, the following adaptation has been suggested. A pipe is made to dip into an open boiler, reaching only an inch or two below[Pg 120] the surface of the water, and passing round the room to be warmed, returns again to the boiler and dips again into the water, descending quite to the bottom of the boiler. An air-pump is connected with this pipe by a small tube; and the air in the pipe being exhausted by this means, the water rises into the pipes above the level of the boiler by atmospheric pressure, and the circulation then takes place by the hot water ascending through the pipe at the top of the boiler, and passing through the whole circuit of the pipe, it returns through the upper end of the pipe which reaches to the bottom of the boiler.
In the last-described form of apparatus the water will rise in the syphon pipe to a height of about thirty feet above the boiler, being that elevation which is due to the action of the atmosphere on liquid flowing through a vacuum. But when a whole house or building is warmed by hot water in all the different floors or heights, a modification of the system, called the high-pressure system, is adopted.
The apparatus on this system consists of a spiral coil of small iron pipe built into a furnace, the pipe being carried from the upper part of the coil, and entwined round the room intended to be warmed, forming a continuous pipe when again joined to the bottom of the coil. The size of the pipe is usually only half an inch in diameter internally, and an inch externally. A large pipe of about two and a half inches diameter is connected, either horizontally or vertically, with the small pipe, and is placed at the highest point of the apparatus. This, which is called the “expansion pipe,” has an opening near its lower extremity, by which the apparatus is filled with water, the aperture being afterwards secured by a strong screw; but the expansion pipe itself cannot be filled higher than this opening. After the water has been introduced, the screw is securely fastened, and the apparatus becomes completely closed in all parts. The expansion pipe, which is thus left empty, is calculated to hold about one-tenth or one-twelfth as much water as the whole of the small pipes; this being necessary in order to allow for the expansion that takes place in the volume of the water when heated, and which otherwise would inevitably burst the pipes, however strong they might be.
In this apparatus the principle of action is different from that in the low-pressure method. Here the water is raised to so high a temperature that it wholly overcomes the effect of gravity, and rises to the highest rooms of a building if required, the circulation through the system of pipes being more rapid as the heat of the water is greater. But there are inconveniences attending the method. If the pipes be[Pg 121] not very strong, they will be burst by the intense pressure from within; as they will likewise if the expansion pipe be too small. If, on the contrary, this latter pipe be too large, it occasions the water to be driven up into it so violently as to leave the lower part of the coil of small pipe almost empty, and therefore liable to be burned by the heat of the fire. And if all these points be properly attended to, there is still the inconvenience resulting from the decomposition of the floating particles in the air, by the highly-heated metal of the pipes. In some cases water, instead of being heated in a coil of small pipes, passes into and through large flat boxes or chambers, whose extended surface enables the surrounding air to be heated more rapidly.
The details of this chapter will enable the reader to perceive, that that part of the builder’s art which relates to the construction of the fire-place rests on more scientific principles, and is more liable to change by successive discoveries and inventions, than most others. It is not simply to make a square opening by the side of a room, to have a vertical chimney or flue above that opening, and a few bars within it; it is not by such means that the object to be answered by a fire-place can be attained; some knowledge of chemistry, pneumatics, and hydraulics, is required before we can properly regulate the combustion of our fuel, the ventilation of our apartments, or effectually warm them by the ascension of hot air, the circulation of hot water, or the condensation of steam.
[Pg 122]
Chapter VIII.
THE WINDOWS AND LEAD-WORK.
We must now give to our dwelling-house those conveniences which call for the services of the glazier and the plumber. These two occupations are so often combined by the same tradesman, and the two classes of operations thereby resulting are both so necessary to the finishing of the exterior of a house, that we may conveniently treat of them in one chapter.
Introduction of Glass-Windows.
Among the features which distinguish modern houses from those existing in the early ages of English history, few have been more conducive to comfort than the adoption of Glass-Windows. Before the employment of that invaluable substance—glass—for this purpose, windows consisted either of uncovered holes in the wall of a house, whereby in order to admit light, the cold would also gain admittance; or else they were holes covered with oiled skin, oiled paper, thin horn, or some other partially transparent material, which would admit a dim light, and yet exclude wind and rain. It is only by placing ourselves in a room thus lighted, that we can form a correct idea of the increase of comfort resulting from the use of glass instead of such imperfectly transparent substances. The slow and imperfect modes of making glass soon after its introduction necessarily gave it a high value, and it could only be employed by the wealthy; but its price has gradually so much lessened, and its claim to a place among the necessaries of life so generally felt and acknowledged, that there are now but few persons in England, except those moving in the very humblest ranks of society, who have not a room with a glazed window.
The Manufacture of Window Glass.
The glass with which windows are generally glazed, is called
Crown glass. It is formed of different materials in different
manufactories. In some instances the materials consist of fine white
sand, carbonate of lime, carbonate of soda, and clippings or waste
pieces of old glass; while in other cases they consist of white sand,
pearl-ash, saltpetre, borax, and arsenic, in certain proportions. On
this point we shall not dwell, for almost every manufacturer has a
favourite receipt of his own. Whatever substances are employed, they
are intimately mixed before being melted. The melting takes place in
large crucibles or melting pots, made of a particular kind of clay
capable of enduring intense heat.[Pg 123] Several such crucibles are placed
in a furnace, a little door being situate in the furnace opposite to
each crucible. Through this door the materials are introduced and are
suffered to melt; and as soon as these become melted, other portions of
the materials are added, until the crucible contains a given amount of
melted material. A curious effect is then observable. Although most or
all of the materials are nearly opaque in their separate states, it is
found that when they are all melted together, they form a transparent
liquid, which is glass.
It requires about forty-eight hours of intense heat to bring the
whole contents of the crucible to a liquid state. During this period,
a quantity of dross or impurity, called sandiver or glass
gall, collects at the surface, and is carefully removed; it is
afterwards sold to refiners of metals, who use it as a flux. The
temperature of the furnace is then gradually lowered, by which means
the glass loses sufficient heat to assume a pasty consistence, which is
more convenient for the workman than if it were perfectly fluid.
The glass maker then stands before the door of the furnace, exposed
to an intensity of heat such as few persons can adequately conceive,
and dips into the pasty mass of glass the end of a hollow iron tube
about five feet long. On withdrawing the tube, a portion of glass is
found adhering to it, and this is made to equalize itself round the
circumference of the tube by turning the latter rapidly round. The
workman then applies his mouth to the other end, and blows through the
tube, whereby the pasty mass is made to assume a hollow globular form
at the remote end of the tube. This process is continued for some time
and with great dexterity, until the globe has attained a considerable
diameter and a proportionably small thickness. The globe is then
somewhat flattened at the side opposite to the tube by pressing it
upon a hard plane surface; and a solid iron rod, called a punt,
having a small quantity of melted glass at the end, is applied to the
centre of the flattened side opposite to the tube, to which it adheres;
the tube is then removed by wetting the glass near the point of union
with the tube, leaving a small circular hole. During these processes
the glass is repeatedly heated by holding it for a few minutes at the
door of the furnace, in order that it may retain the requisite degree
of softness.
The punt, with the flattened globe of glass at its end, is then
rapidly whirled round in a manner nearly resembling that in which a mop
is twirled. By this motion, the globe becomes more and more flattened
and extended in diameter, until at length, not being able longer to
retain its shape, it bursts open, and spreads out in the form of a
flat circular[Pg 124] sheet of glass three or four feet in diameter. There
is perhaps nothing in the whole range of the mechanical arts more
astonishing to a spectator than this process, and there are few that
require, from the workman, more of that dexterity of hand which can
only be acquired by long practice. The workman continues to whirl the
sheet of glass round,—gradually receding from the furnace,—until it
is sufficiently set or solidified to retain its form. The punt is then,
by a dextrous movement, detached from the centre of the sheet, leaving
that bulb which is known as the “bull’s eye,” or the “knot.” The sheet
is placed in an annealing oven, the temperature of which is lowered by
slow degrees until cold; for it is found that glass is less brittle
when it has been allowed to cool gradually than when the cooling has
been rapid. Considerable care is required to regulate the temperature
of the annealing oven; if the heat be too great the softened glass will
bend: if the heat be insufficient the plates are liable to crack, or
they prove so brittle that when they come to be used, the glazier will
not be able to divide the glass so as to suit his purposes. Indeed,
the management of the heat in the manufacture of crown glass requires
so much care and skill that few workmen produce an article of the same
value, even though working at the same furnace; hence crown glass is
known in the market as firsts, seconds, thirds, and fourths; the fourth
quality producing less than one-half of the price of the first.
We have not interrupted this description, to refer to engravings; but
we may now illustrate it by the following cuts representing the glass
in eight different stages of its formation.
1st. The melted glass attached to the tube, and worked on a board.
[Pg 125]
2nd. The workman blowing through the tube, to expand the glass.
3rd. Whirling it rapidly at the mouth of the furnace.
4th. Transferring it from the hollow tube to the solid punt.
[Pg 127]
5th and 6th. Successive stages of expansion, by constant and rapid
rotation.
7th. Final expansion into a flat circular sheet.
[Pg 129]
8th. The sheet of glass, held on a kind of fork, being placed into the
annealing oven.
When cold, the sheets of glass are cut into two unequal pieces, one of
which contains the knot, and are packed with straw in wooden
crates, in which they are forwarded to the warehouses, and from
thence to the glaziers.
As plate glass is sometimes used for windows, a slight notice of it
seems to be necessary in this place, in order that the reader may have
a clear idea of the difference between these two descriptions of window
glass.
The manufacture of plate glass is confined to very few hands, and
great reluctance is manifested by the proprietors to permit visitors
to inspect their works. The late Parkes, however, was permitted to
visit the works of the British Plate Glass Company, at Ravenhead, and
has recorded his observations in one of his valuable chemical essays,
from which the following details are taken.
In the preparation of plate glass the materials are selected with
greater care than in any other branch of the glass manufacture. The
materials employed are sand of the finest and whitest kind, soda, and
lime. Manganese and oxide of cobalt are also used for the purpose of
destroying colour, which they do by the curious, and at first view,
paradoxical property each has of imparting colour. The manganese has
the effect of a slight tinge of red, the cobalt of blue; while the sand
and alkali produce a slight yellow tinge; and thus these three colours
(being those which naturally produce white light) by proper combination
in the glass neutralise each other, and the result is an almost
perfectly transparent material.
The process of filling the pots and fusing the materials is similar
to that already described for crown glass. The crucibles[Pg 130] are of
two kinds; the larger ones wherein the glass is melted, are called
pots, and because these when full of glass are too bulky and
heavy to be moved, smaller ones, called cuvettes, are employed.
These are kept empty in the furnaces, exposed to the full degree of
heat, so that when the glass is ready for casting and is transferred to
them, they may not greatly lower its temperature.
The subsequent operations are very well described in an abstract of
Parkes’s essay, given by the writer of the volume on Glass and
Porcelain, in the .
“When the glass is thoroughly refined, the cuvette—which must be
perfectly clean, and, as already mentioned, of a temperature equal
with that of the glass—is filled in the following manner:—A copper
ladle, ten to twelve inches in diameter, fixed to an iron handle seven
feet long, is plunged into the glass pot, and brought up filled with
melted glass, which is transferred to the cuvette; the ladle during
this transference is supported upon a strong iron rest, placed under
its bottom, and held by two other workmen. This precaution is necessary
to prevent the bending and giving way of the red-hot copper under the
weight of fluid glass which it contains. When by successive ladlings
the cuvette is filled, it is suffered to remain during some hours in
the furnace, that the air bubbles formed by this disturbance may have
time to rise and disperse; an effect which is ascertained to have
ensued by the inspection of samples withdrawn from time to time for the
purpose.
“Another essential part of the apparatus consists in flat tables
whereon the plates of glass are cast. These tables have perfectly
smooth and level metallic surfaces, of suitable dimensions and
solidity, supported by masonry. At Gobain, and formerly also at
Ravenhead, these tables were made of copper; the reason assigned
for preferring this metal being, that it does not discolour the hot
melted glass, while the use of iron was thought to be accompanied by
this disadvantage. These copper tables were very costly, both from
the nature of their material, and the labour bestowed in grinding
and polishing their surfaces; and as the sudden access of heat that
accompanied the pouring over them of such a torrent of melted glass
occasioned the metal frequently to crack, the tables were by such an
accident rendered useless. The British Plate Glass Company having
experienced several disasters of this nature, its directors determined
upon making trial of iron; and they accordingly procured a plate to be
cast, fifteen feet long, nine feet wide, and six inches thick, which
has fully answered the intended purpose—having, during several years
of constant use, stood uninjured[Pg 131] through all the sudden, and violent
alternations of temperature to which it has been exposed. This table is
so massive, weighing nearly fourteen tons, that it became necessary to
construct a carriage purposely for its conveyance from the iron foundry
to the glasshouse. It is supported on castors, for the convenience of
readily removing it towards the mouths of the different annealing ovens.
“The foundry at Ravenhead wherein this table is used is said to be
the largest room under one roof that has ever yet been erected in
this kingdom; it is 339 feet long, 155 feet wide, and proportionately
lofty. Westminster Hall, to which the superiority in this respect
is so commonly ascribed, is smaller—its length being 300 and its
breadth only 100 feet. The melting furnaces, which are ranged down the
centre, occupy about one-third of the whole area of this apartment.
The annealing ovens are placed in two rows, one on each side of the
foundry, and occupy the greatest proportion of the side walls. Each
of these ovens is sixteen feet wide and forty feet deep. Their floors
being level with the surface of the casting table, the plates of glass
may be deposited in them immediately after they are cast, with little
difficulty and without delay.
“When the melted glass in the cuvette is found to be in the exact
state that experience has pointed out as being most favourable for its
flowing readily and equably, this vessel is withdrawn from the furnace
by means of a crane, and is placed upon a low carriage, in order to
its removal to the casting table, which, as it is previously placed
contiguous to the annealing oven that is to be filled, may therefore
be at a considerable distance from the melting furnace. Measures are
then taken for cleaning the exterior of the crucible, and for carefully
removing with a broad copper sabre any scum that may have formed upon
the surface of the glass, as the mixture of any of these foreign
matters would infallibly spoil the beauty of the plate. These done,
the cuvette is wound up to a sufficient height by a crane; and then,
by means of another simple piece of mechanism, is swung over the upper
end of the casting table; and being thrown into an inclined position,
a torrent of melted glass is suddenly poured out on the surface of the
table, which must previously have been heated, and wiped perfectly
clean.
“The glass is prevented from running off the sides of the table by ribs
of metal, one of which is placed along the whole length of each side,
their depth being the exact measure which it is desired to give to the
thickness of the glass. A similar rib, attached to a cross piece, is
temporarily held, during the casting, at the lower end of the table.
When the[Pg 132] whole contents of the crucible have been delivered, a large
hollow copper cylinder, which has been made perfectly true and smooth
in a turning lathe, and which extends entirely across the table,
resting on the side ribs, is set in motion; and the glass, during its
progress, is spread out into a sheet of uniform breadth and thickness.
Its length depends upon the quantity of melted glass contained in the
cuvette: should this be more than is needed for the formation of a
plate having the full dimensions of the table, the metal rib is removed
from its lower part, and the surplus glass is received in a vessel of
water placed under the extreme end for the purpose.
“ Parkes, in speaking of this operation, remarks—‘The spectacle
of such a vast body of melted glass poured at once from an immense
crucible, on a metallic table of great magnitude, is truly grand; and
the variety of colours which the plate exhibits immediately after the
roller has passed over it, renders this an operation far more splendid
and interesting than can possibly be described.’
“At least twenty workmen are busily employed during this process of
casting. From the time that the cuvette is removed from the furnace,
to the completion of the casting by the hardening of the glass, the
apartment must be kept as free as possible from disturbance; even
the opening and shutting of a door might, by setting the air in
motion, disturb the surface of the glass, and thus impair the value
of the plate. So soon as it is completely set, the plate is carefully
inspected; and should any flaws or bubbles appear upon any part of its
surface, it is immediately divided by cutting through them.”
“When the plate of glass thus formed has been sufficiently fixed by
cooling, it is slipped from the table gradually and carefully into one
of the annealing ovens, where it remains in a horizontal position; its
treatment differing in this respect from that pursued with crown and
broad glass, which stand on edge during the annealing process. As each
oven in this manner becomes filled, it is closed up by an iron door,
the crevices of which are carefully stopped with mortar or clay, to
prevent an access of external air to the oven; and thus to provide as
far as possible for the gradual cooling of the plates, the necessity
for which has already been sufficiently explained. When the glass has
remained during about fifteen days in these ovens, they are opened, and
the contents withdrawn.”
The plates have then to undergo the operations of squaring, grinding,
and polishing, which need not be described in this place.
[Pg 133]
The various kinds of glass manufactured in Great Britain amount every
year to the enormous quantity of 300,000 cwt., which is valued at two
millions sterling.
Glass Cutting.
Such, then, being a few details as to the mode of manufacturing glass;
we will next suppose that the glass has reached the hands of the
glazier or glass-cutter; and that the window-frame or sashes are ready
to receive the panes of glass.
One of the earlier operations of the glazier is to prime the
sash, that is, to give it a coat of thin paint, for the purpose of
making the putty adhere more firmly to the wood. He next takes the
dimensions, in inches and eighths of an inch, of the groove or rebate
in which each square of glass is to be fixed, and then proceeds to cut
squares of those sizes from the semicircular pieces in his crate. This
requires much tact and judgment, since to procure square or rectangular
panes necessarily entails a loss of some of the circular portions.
The circular sheets are made of diameters varying from forty-eight to
sixty-four inches, and these are cut at various distances from the
central knot, so that the glazier is enabled to choose that piece which
experience teaches him will entail least waste: sometimes it is better
to cut the pane from a table (the half which contains the knot),
sometimes from a slab (the remaining portion of the disc).
In order to cut a table or slab, so as to procure a pane of the proper
size, the straight edge of the table is placed near the glazier,
and he cuts at right angles to it, by means of a diamond, and of an
instrument called a square; and two other cuts, at the proper
distances, are sufficient to give a pane of the required size. With
respect to the power by which a diamond is enabled to cut glass, we may
explain it by saying, that it is a general rule among mineralogists,
lapidaries, and others concerned with stony or crystalline bodies,
that the hardest among a certain number of bodies will cut,
or at least scratch, any of the others:—in fact, tables of
the hardness of different substances are formed from the
determination of what substances will mark or scratch others, that one
being reckoned hardest which will scratch all others, without being
equally affected by them in return. Now the diamond is the hardest body
in nature, and cannot be cut by any substance but its own dust; but it
can cut glass and other bodies, which are not so hard as itself.
[Pg 134]
The Process of Glazing.
The glass having been cut to the right size, it is next to be fitted
into the sash; and among the many kinds of cement which might be
suggested for this purpose, oil putty is found to be the most
advantageous, since it is conveniently soft when used, but hardens
afterwards to the consistence of stone. Putty is made of whiting and
linseed oil. The whiting is purchased in lumps, which are well dried,
and then pounded and sifted. The linseed oil is poured into a tub, and
the powdered whiting added to it, and stirred up with a stick. When
some degree of stiffness is attained, the mass is taken out of the tub
and placed upon a board, where more whiting is added, and the whole
mixed up by hand. The mass is then beaten for a long time with a wooden
mallet, until it attains a perfectly smooth and uniform consistency.
A portion of putty is taken up on a knife, and inserted in the groove
of the window sash. The pane of glass is then laid in the groove, and
gently pressed down in every part, so as to lie on the putty. As the
sheets of glass are never perfectly flat, it is a rule among glaziers
to let the concave side of a pane be within doors and the convex
side without. After the glass is laid in, the edge is carefully coated
with putty, to the extent of about an eighth of an inch: if this be
carefully done, it is sufficient to secure the glass in its place,
without presenting an unsightly appearance from the interior of a room.
The opposite side of the glass now requires a little attention, since
the bed of putty originally laid in the groove has been partially
squeezed out by the pane of glass: a little trimming and finishing are
all that are required in this matter.
When a broken pane is to be replaced in a window, it is done generally
without taking out the sash; but in the case of glazing the sashes of a
new house, such as we have been supposing, it is done before the sashes
are fitted into their places. If sashes are glazed with plate
instead of crown glass, the only difference in the glazier’s
method of proceeding is, that the pane being heavier, must be fixed in
with greater attention to security. Sometimes a small beading or fillet
of wood is used instead of putty, in which case it is either nailed or
screwed to the sash.
Where skylights are used instead of windows, a different plan must
be observed, since there are no cross bars to the sashes. In this
case the squares of glass are fixed in somewhat in the way adopted in
slating a roof, that is, the lower pieces are puttied in first, and
the upper ones are lapped over[Pg 135] them, so that each pane projects about
three-quarters of an inch over the one next below it. This is to effect
two objects,—to prevent the necessity of puttying the joints, and to
exclude rain.
Ground, fluted, painted, stained, and
embossed glass, are occasionally employed for windows. These
need not be noticed, since the processes by which they are fluted,
stained, &c., would carry us to details of too extensive a nature. So
far as the glazier is concerned, rather more care and delicacy are
required in proportion as the kind of glass employed is more costly or
more ornamental.
In some of the better kinds of houses, rooms are provided with double
windows, separated a few inches from one another. The object of this
is, to prevent the room from being affected by rigorous cold from
without; for a mass of air when stationary, conducts heat very
slowly; the stratum of air between the two windows, therefore,—being
stationary,—is slow to conduct the cold from without, or, more
correctly, to conduct the warmth from within.
Sheet Lead for Roofs and Cisterns.
Whether the glazier precedes the plumber or the plumber the glazier,
or whether the labours of both alternate during the building of a
house, is a question of no great importance to our present object. We
will therefore proceed to notice the kind of material employed by the
plumber.
The comparative cheapness of lead, its admirable qualities, and the
facility with which it can be cast and rolled into thin sheets, and
drawn into pipes, cause it to be extensively used in building. The
most productive mines of this metal in our own country are situated in
Derbyshire, Devonshire, Cornwall, in Wales, and in the North; in short,
the ore from which lead is generally obtained, called Galena,
or Sulphuret of Lead, is found in all countries where the
primary rocks appear at the surface. The ore greatly resembles the pure
metal in brilliancy; but it is brittle, and not so easily fused. It
frequently contains a sufficient quantity of silver to make it worth
while to adopt a peculiar process in the reduction of it, in order to
separate this more valuable metal. The ore is first broken into small
pieces, and is then roasted in a reverberatory furnace, to drive
off the sulphur. When this object is attained, the heat is increased,
till the metal is fused, and then it is drawn off into moulds, which
give it the form of blocks or slabs, called sows and pigs.
Sheet lead is made thus:—A large furnace is provided, into
which pig-lead is thrown, and heat applied. When[Pg 136] the lead is melted, a
valve or cock is opened in the side of the furnace, and the glistening
liquid metal pours forth, and falls on a large table, covered over
with an even surface of fine sand, and having a ledge of an equal
height above the sand all round it. When the melted metal is poured on
the sand, two men, holding each end of a stiff wooden rule, called a
strike, draw it along the table, resting on each side ledge: the
liquid lead is pushed onwards by the strike, till it covers the whole
surface of an even thickness, which of course is governed by the depth
of the ledge round the table.
Milled sheet lead is formed by rolling a cast plate of the metal
between large iron rollers, turned by machinery. These rollers are set
closer and closer together, till the lead is reduced by rolling to the
requisite degree of thinness. By this process, the lead is rendered
more dense and more equally so, than it ever is by simply casting:
milled lead, consequently, is more durable than cast-lead.
It should be here noticed that lead, when it is used for roofing, or
for lining cisterns and gutters, is always laid on an even boarded
surface, and not on battens or laths, like slate and tiles.
Lead Pipes.
Lead pipe is either formed by bending thin sheet lead round a cylindrical mould, and soldering the joint; or when the pipe is less than four or five inches in diameter, it is formed by casting a thick cylinder of lead with a small bore, and about five or six feet long. A long smooth iron rod, a little larger than the bore of the cylinder, is forced into this, and then the cylinder is gradually drawn through a succession of circular holes, decreasing in diameter, in a steel plate, by means of a powerful draw-mill, worked by a steam-engine. The lead is by this process extended out over the iron rod, which preserves the bore of the pipe of an equal diameter, and when the pipe is sufficiently reduced in thickness, the rod, or triblet, is forcibly drawn out, and the pipe left with a smooth bore, ready for use. Attempts have been made to form lead pipes wholly by casting; an outer mould and an inner core being so adjusted as to leave a space between them, into which lead might be forced while in a melted state; but this method has not been practically worked out to any great extent.
The Process of Plumbing.
When a roof is to be covered, or a cistern lined, with lead, the
sheet of the metal is unrolled on a level floor, and made[Pg 137] free from
creases and undulations, by beating them down with a heavy wooden
flogger, formed like a roller with a flattened side, and a
handle to it. The plumber then draws on the lead the form into which it
must be cut to fit the surface it is intended to cover, and afterwards
cuts through the lines described with a strong sharp knife. The piece
is then rolled up again for facility of carriage, and raised by tackle
into its intended situation, it being placed there so that when again
unrolled, it may lie in the proper situation and position on the
boarding. The sheet is then again beat out flat as before.
The next sheet being put into its place, and so that the edges of
the two may overlap about one and a half or two inches, the workman
proceeds to make the joint, or to solder the two sheets together. The
first step for this purpose is to scrape the two edges or borders of
the sheets that are to come in contact quite clean and bright, with a
tool constructed for this purpose, consisting of a small triangular bit
of steel ground sharp at its edges, and fastened at right angles on
an iron socket, fixed in a handle. When these borders of the lead are
quite clean, they are painted over with black-lead paint, to prevent
their tarnishing, or oxidising again, as the solder will only
adhere to a clean pure metallic surface. The paint also serves as a
flux to cause the solder and lead to melt together, and thus make a
close joint.
The solder is melted in an iron ladle, on a rude temporary fire-place,
built as near the spot where the solder is wanted as possible. The
plumber having turned back the edge of the upper sheet at the joint,
an assistant carefully pours the solder on the lower edge. The workman
then spreads it evenly along the joint, by means of soldering
irons, which are irregularly-shaped iron bars, swelling at their
ends into rounded forms of different sizes and shapes, according to the
particular purpose for which they are intended. These irons are used in
a red-hot state in order to keep the solder melted.
As soon as the workman has spread the solder, he presses and hammers
down the upper edge upon the lower, and spreads the solder forced out
of the joint, along the seam. The outermost edge of the lead covering
is nailed down to the boarding or cistern-frame by nails, with their
heads leaded over to prevent the corrosion of the metal, by the
chemical or voltaic action that takes place when two metals in
contact are exposed to moisture. The situation of the soldered joints
depends on the size and form of the surface to be covered over; and a
good workman considers well how he can cut out the lead so as to have
the fewest joints, and these in[Pg 138] the most favourable situations. If he
has to line a cistern, he will cover the bottom in one piece, cutting
the lead large enough to admit of its turning up for an inch or two at
two of the sides, the joint consequently being made at these angles.
When a large roof, like that of a church, is covered with lead, this
is laid on in parallel bands as wide as the sheet will admit of, the
edge of one sheet being turned over a wooden roller or fillet, nailed
down on the boarding to receive it, while the edge of the next sheet
is turned over the former lead again; the double thickness being well
flogged down to render the joint water-tight: and in this case
no solder is used.
The edges of lead gutters that turn up against the inside of the
parapet are either laid as flat against the brick-work as possible, and
secured so by iron holdfasts, so as to prevent rain from getting
in; or to effect the same object, they are in all the better kind of
buildings, turned into a joint, in the brick-work, between two courses.
When the plumber has to join two lengths of lead pipe into one, he
opens out the end of one length into a funnel-shaped aperture, by
gently driving a wooden cone into it, so as to avoid splitting the
pipe. The end of the other length is then scraped down a little by the
triangular tool before mentioned, not only to obtain a clean surface
for soldering, but to allow of the end fitting into the funnel-shaped
aperture alluded to. The two pipes being thus put together, the workman
holds a thick wadding of old woollen cloth, well greased, under the
joint, while a labourer gently pours melted solder over the joint,
which the plumber smoothes and shapes down by his soldering-iron and
the cloth into a regular smooth rounded swelling, all round the joint,
making this perfectly close and water-tight.
We observed in the chapter on “Roofs,” that within the last few
years, the metal zinc has been much used instead of lead for all
the purposes of the latter, and many others beside, for which the
admirable qualities of zinc particularly qualify it. This metal is
lighter than lead, and equally durable in the open air. It bears water
almost equally well; but it is not so flexible or manageable, being
neither so fusible nor malleable. Zinc only admits of being rolled or
hammered when it is heated to about two hundred and twenty degrees
of Fahrenheit. When cold it is too brittle to bear much bending;
nevertheless, pipes, gutters, cisterns, chimney-pots, &c., are made out
of sheet zinc; and roofs, &c. covered with it.
[Pg 139]
Solder or Cement for Metals.
The solder alluded to above, as being the means of joining two pieces
of sheet lead or of lead pipe, is an alloy of lead and tin, in the
proportion of two parts of the former to one of the latter. This mixed
metal is fusible at a lower temperature than either the tin or the lead
separately; and may therefore be applied in a melting state to tin or
lead, which still remains solid, even at the same temperature: this it
is which constitutes the principle of soldering. The solder is cast
into triangular bars, weighing from thirty to fifty pounds each.
There has, however, been a method recently introduced which seems
likely to effect considerable changes in the mode of joining pieces of
metal, whether for buildings or for other purposes; and we may here
give some account of it.
The great object of soldering is of course to form joints or seams in
pipes, and other articles, so perfectly, that they shall be subject to
no leakage or flaw. But this object is not easily obtained by the old
method of soldering; the chances of flaw are numerous, and have been
enumerated thus:—1st, the difference of expansion between the lead and
its alloys with tin, a difference which is particularly experienced
in very cold or very elevated temperatures; 2nd, the electro-chemical
actions which are developed under certain circumstances by the contact
of two different metallic substances;[5] 3rd, the very powerful
reaction which a number of chemical agents exert on alloys of lead and
tin, though not upon lead alone; 4th, the extreme fragility of these
alloys, which, particularly when heated, often break on the slightest
blow; 5th, the difficulty of making the solder adhere to the surface of
the lead;[6] 6th, the use of rosin, which frequently conceals fractures
for a time.
All of these objections are removed by a new method of soldering,
invented by M. E. Desbassays de Richemont, who has recently obtained,
at the National Exhibition of Arts at Paris, a gold medal for his
invention. The committee on whose recommendation the medal was awarded,
included some of the most distinguished chemists and men of science [Pg 140]in France; and in their report on the subject, they say:—“We consider
this invention of the highest importance; it is applicable to many
branches of industry, and will render great service to a large number
of manufactures. Its efficacy has not only been proved by experiment,
but is confirmed by the fact, that most of our eminent manufacturers
and tradesmen have taken out licences for the use of it.”
This invention (which is patented in France, Great Britain, and
Ireland) is called autogenous soldering, and consists of a
method of uniting two pieces of metal without the use of solder.
The parts to be joined are united by the fusion of the metal at the
points or lines of junction; so that the pieces when joined form one
homogeneous mass, no part of which can be distinguished from the rest.
This result is obtained by means of jets of flame, produced by the
combustion of hydrogen gas, mixed with atmospheric air; these jets are
so ingeniously managed, that they can be used and directed with as
much, or even more facility, than the common tools of the solderer.
The apparatus employed in this new process consists of a peculiarly
constructed vessel for producing hydrogen gas, to which vessel a
variety of tubes and jets can be attached, so as to meet the various
demands of the solderer.
A section of the gas-producer is shown in 1: a is a leaden
tank, for containing dilute sulphuric acid; b, a pipe which
passes from the acid vessel to another similar leaden vessel, c,
which is to contain cuttings of zinc; d is a conical plug,
with a stalk and handle covered with lead, by the opening of which
the acid is allowed to flow through the pipe b, to the zinc
cuttings, and thus hydrogen gas is produced; e is an opening
by which zinc is put into the vessel c. The opening, e,
has a cover furnished with screws and nuts, by which it may be firmly
secured; f is an opening by which acid and water are poured
into the vessel a. When the hydrogen gas is produced, it has to
pass through the safety chamber g; h is a bent tube or
pipe, which conducts the gas from the vessel c to the bottom of
the safety chamber, the mouth of the pipe dipping into an inch or two
of water in the safety chamber. This water is introduced by the pipe
i, which is furnished with a stopple. The cock, k, cuts
off the flow of gas from the vessel c, to the safety chamber,
g. A flexible tube, m, is screwed to the top of the
safety chamber, and conveys the gas to the working instrument, or jet,
in the hands of the solderer.
As long as the dilute acid is allowed to flow upon the zinc, hydrogen
gas will be produced: the gas will also be formed as long as the
cock is open, which allows the gas to issue as[Pg 141] it is produced; but
as soon as the cock is shut, a small quantity of gas accumulates,
and interferes with the further action of the liquid on the zinc.
Consequently there is no danger of an explosion, because the production
of the gas is never more than is required for working; and when the
work ceases, the production of the gas ceases also. When the dilute
acid has become saturated with oxide of zinc, and gas ceases to be
produced, the discharging pipe is opened, and the liquid withdrawn. By
spontaneous evaporation, this liquid furnishes sulphate of zinc (white
vitriol), which may be sold at a price which will more than cover the
first and daily cost of the apparatus.
1.
[Pg 142]
2.
We now proceed to describe the part of the apparatus with which the
workman operates. In 2, the flexible tube, m, is attached
to one arm of the forked tube, o; the other arm of o
is attached to a pipe, q, proceeding from a bellows, or other
means for supplying air. The solderer may work a bellows with his
foot to supply his apparatus with air, or the men in a whole factory
may be supplied from a blowing apparatus. A cock, n, regulates
the supply of gas; p is a cock for regulating the supply of
air; r is the pipe or tube in which the gas and air are mixed;
s, the beak or tool, from which issues the jet of flame,
t, with which the workman operates.
The forked tube, o, is attached to the girdle of the workman,
and the regulating cocks, n and p, are so placed, that by
using one hand, the man can allow the exact proportions of air and gas
to issue. By stopping both cocks, the flame is of course extinguished.
The beak, s, may be exchanged for others of every variety of
form, so as to produce jets of flame adapted to any kind of work.
3 is a tool formed like the rosette of a watering-pot, capable of
producing a most intense flame of jets.
[Pg 143]
3.
4.
4 allows a length of flame instead of a point to be produced;
n is the hydrogen gas-pipe and cock; p, the air-pipe and
cock; r, the tube, in which air and gas mingle; u, a pipe
with a longitudinal slit on one side of it; and v, another pipe
covering u, and exactly fitting over it. Gas and air escaping
from the slit, on being ignited, will produce a long strip of flame,
which may be lengthened or shortened by sliding off or on the covering
tube, v, on the slit tube u.
5.
5 is a soldering tool, to be used where a jet of flame is not
available, as in joining zinc. In this arrangement, the hydrogen and
air flame heats apiece of copper, y, with which the work is
performed. w is the tool, with a hollow handle and stalk; air
being supplied by the pipe p, passes through the hollow handle
and stalk; x is a small tube which passes down the hollow handle
and stalk, w, and conveys gas from the pipe n to the
extremity of w, where it mingles with the issuing air, and,
on being ignited, the flame will heat the piece of copper, y,
(which, of course, may be of the shape of any soldering tool required,)
held by the arms, z.
[Pg 144]
Advantages of the Improved Method of Soldering Metals.
One great advantage to the public at large to be derived from the
general introduction of “autogenous soldering,” will be the diminution
of the number of cases of the escape of water and gas, which every day
occasion so much inconvenience and even danger as regards the stability
of buildings, the maintenance of the public thoroughfares, and the
security of life.
The disuse of charcoal and tin by plumbers will have the important
effect of rendering their trade less unhealthy, the fumes from their
brasiers, and the arsenical vapours emanating from impure tin, being a
very common cause of serious maladies.
By the old method of soldering, there is great danger of setting fire
to houses and public buildings: the destruction of the corn market of
Paris, and of the Cathedrals of Chartres and of Bruges, by fire, was
partly owing to the negligence of plumbers; a negligence for which
there could be no reason, if the new method of soldering had been
introduced, since it is only necessary to turn a cock in order to
extinguish or rekindle, at any moment, the jet of gas which serves for
the plumber’s tool. By means of the new apparatus, a soldering flame
can be conducted to a distance of several fathoms without the dangerous
necessity of lighting a brasier to heat irons, to melt masses of
solder, and to carry the whole into the midst of complicated carpentry
work.
The disuse of solder will also greatly reduce the price of plumber’s
work, without, however, diminishing the demand for the services of the
workmen. The disuse of seams or overlapping, which from this new mode
of connecting lengths of lead will almost entirely be given up, will
alone occasion a considerable saving in the quantity of lead employed.
The ease with which lead of from one-thirtieth to one-tenth of an inch
in thickness may be soldered, and defects repaired, will permit of
the substitution of this, in many cases, for thicker lead, and thus
diminish the expense; perhaps, also, it will give rise to the use of
lead for purposes to which it has not yet been applied, or the return
to others, in which from motives of economy it has been superseded by
other metals.
The plumber will also be indebted to M. de Richemont’s method for
several important improvements. He will be able in future to make
internal joints wherever a jet of flame can be introduced and directed;
to reconstruct on the spot, of pure lead, any portion of a pipe,
a vase, or a statue, that may[Pg 145] have been removed or destroyed; to
execute in rapid succession any number of solderings; to repair in
a few minutes all dents, cracks, and flaws, in sheets or pipes of
new lead; to remove entirely the enormous edges or knots left by the
old-fashioned joints, and that without weakening them; to give, in
short, to works of lead a precision of execution, and a solidity,
unattainable up to this time.
Autogenous soldering will also be of great assistance to several
chemical manufactures, where it is so important to have large vessels
of lead without alloy. By uniting a number of sheets into one, vessels
of pure lead of any size may be formed for the process of acidification
and concentration of saline solutions; for the formation of scouring
vats employed by so many artisans who work metals; for vessels of every
kind used to contain liquids which act upon tin solder.
In the repair of leaden vessels exposed to the action of heat, peculiar
advantages are offered by autogenous soldering. By the old method, the
holes which are so often caused in the bottoms of these vessels, either
by the action of sudden flames, or by deposits that form on their
surface, can be stopped only when they are not of too large dimensions,
by making what are called weldings of pure lead. The cases in which
this mode of repair is available, are very limited, and whenever it is
impracticable, the boilers must be taken down, the lead changed, and
then reset; thus occasioning considerable expense and an interruption
to business. By the new method, nothing is easier than to apply pieces
to the bottom or sides of the vessels, whatever be the size of the
holes, and thus the whole of a boiler may be renewed piecemeal. By
this plan, too, the old lead remains uncontaminated with solder, and
consequently will yield a pure metal to the melting-pot.
The great ductility of lead, which, in many cases, is one of its most
valuable qualities, is, however, an inconvenience when instruments or
utensils are required of considerable strength. At the same time, there
are circumstances where this metal alone can be employed, on account
of the manner in which it resists chemical action. By constructing
vessels or instruments of iron, zinc, or wood, and covering them with
lead, utensils can be formed that will resist pressure and blows, and
most chemical agents, as well as if they were made of solid lead.
Such vessels are required in the preparation of soda, and other
gaseous waters; in the distillation or evaporation of acid or alkaline
solutions; and for many other purposes.
Another application that deserves especial notice is that of lining
common barrels with thin sheet-lead. These vessels[Pg 146] would be of great
utility in chemical factories, more particularly in the construction of
Woulf’s apparatus, and other pneumatic instruments, to which greater
dimensions could be given by this means; but they could be employed
with singular advantage in the transport of acid and alkaline liquids
by sea and land. Sulphuric and muriatic acids are transported in stone
bottles, or glass carboys placed in baskets, which, however carefully
packed, are liable to be broken, not only with the loss of the acids,
but with danger to surrounding bodies. We are told of two French ships
that perished at sea on a voyage to the colonies, in consequence of the
breaking of some bottles of sulphuric acid.
In the manufacture of sulphuric acid, the use of ordinary solder is
impracticable, since it would soon be corroded. The following method
was introduced some years ago for forming sulphuric acid chambers, and
the concentration pans. Two edges of lead being placed in contact,
were flattened down into a long wooden groove, and secured in their
situation by a few brass pins driven into the wood. The surfaces
were next brightened by a triangular scraper, rubbed over with
candle-grease, and then covered with a stream of hot melted lead. The
riband of lead thus applied, was finally equalized by being brought
into partial fusion with the plumber’s conical iron, heated to redness;
the contact of air being prevented by sprinkling rosin over the
surface. The autogenous soldering apparatus will greatly simplify the
above method.
The advantages to be derived from the new process, are by no means
confined to lead: the apparatus may be employed in using for solder
either the common alloys, or pure lead, to unite zinc, and iron, and
lead, with iron, copper, and zinc. It may be substituted also with
advantage for the common blow-pipe and lamp of the enameller in all
their applications to the soldering and joining performed by the aid of
these instruments by jewellers, goldsmiths, tinmen, manufacturers of
plated goods, of buttons, &c.
The flame produced by the combustion of the gas may be most
economically employed for heating soldering irons. A few seconds
suffice to bring the iron to the desired temperature, and it can be
kept at that temperature for many hours without being liable to burn,
nothing more being necessary than to regulate the flame by means of
cocks, and the workman need not be obliged to change his iron, or even
to leave it for a single moment. Hence there is not only a considerable
saving in manual labour, but also in fuel, which in most cases is of
greater consequence.
Such are a few only of the advantages of this simple and beautiful
invention, which is now very extensively adopted in[Pg 147] France, and will
doubtless get into extensive use in this country, when its merits are
more generally known.
It may be here stated, in justice to some of our own ingenious
countrymen, that after this method had become extensively known,
M. Richemont’s claim to the invention was disputed. We have been
informed, that previously to the year 1833, a Mallet had employed
an apparatus constructed on the same principle, and used in a similar
manner, as that already described as the invention of M. de Richemont.
In Loudon’s ,
published in 1833, the following passage occurs:—“ Daniell, of
King’s College, London, has since published the same thing as new, and
of his invention: however, I can establish priority by my laboratory
journal.”
FOOTNOTES:
[5] Messrs. Vauquelin and D’Arcet state that they have seen in
soap-works the soldering of vats lined with lead crumble in a few days
to a powder. The same has been remarked of leaden pipes passing through
certain soils.
[Pg 148]
[6] The solder often sticks without uniting and the workman may be
quite ignorant of his imperfect work; and thus gas, water, or dangerous
liquids, may be allowed to escape.
Chapter IX.
THE INTERIOR—PLASTERING AND PAPER-HANGING.
As men rise above the rude condition of uncivilized nations, they are not satisfied with the mere necessaries of life. Their standard of comfort becomes elevated. Those things which are luxuries to the lowest class are comforts to the next higher class, and necessaries to the class which is higher still in the social scale; so that the interpretation given to the words, “luxuries,” “comforts,” and “necessaries,” becomes a sort of index whereby to mark the grade which an individual occupies. A roof to cover the dwelling, a glass window which may exclude the wind and the rain, while it admits light,—a fire-place, with appliances for carrying off smoke and the products of combustion—however far above the standard of the uncivilized man—are not sufficient for the Englishman of middle station. He must have his rooms nicely squared and neatly fitted; the roof must be concealed from view by a smooth white ceiling; the rough brick walls must be covered not only with plaster, but with an ornamental covering of paper or paint. Hence arises occupation for many artisans whose sole business is to make the dwelling agreeable to the eye, after the more necessary and indispensable parts of the structure have been finished.
Plastering Walls and Ceilings.
The occupation of the plasterer is generally united with that of the
bricklayer. The business of the plasterer, as such, is to cover over
the rough walls and ceilings of a building with plaster, which
is the name given to a better kind of mortar, made of lime only. When
this plaster is of the coarser kind for the under or first coating,
cow-hair is mixed with it to make it bind better. When a plain brick
wall is to be plastered, the surface is at once covered with the
plaster, this adhering readily to the rough brick-work: but for
ceilings or partitions, a groundwork of laths is required to receive
the first coating.
Laths are of different sizes and qualities, according to the various
work for which they are intended. Those used by the plasterer are
termed single, and are about from two to three feet long, an
inch broad, and a quarter of an inch thick. They are split out of a
coarse kind of deal. Double laths are considerably longer and
thicker, and are sawn out:[Pg 149] they are therefore regular in their size.
They are used for better work in plastering, but chiefly by tilers or
slaters.
The single laths are nailed up to the joists of the ceiling, or to the
quartering of partitions, with but a small interval between
each, so as entirely to cover the surface. The workmen then proceed to
cover the lathing with coarse plaster, a labourer supplying them with
a small quantity at a time on a square board, held in the plasterer’s
left hand by means of a short thick handle stuck upright into the back
of the board. The man uses a rectangular flat wooden trowel, with a
bridge-shaped handle, to transfer the stuff from the board to
the wall, and to spread it evenly over the surface. When the room of
which the walls are being plastered is of a better description, the
work is floated, that is, a regular surface is obtained by
drawing a long straight-edge over the wet plaster, so as to scrape off
the inequalities and reduce the whole to a plane surface.
A thinner coating of finer plaster is spread over the first to finish
the plastering, and this is again floated in drawing-rooms, and so on.
Plaster and Papier-Maché Ornaments for Rooms.
The mouldings of cornices in rooms are formed by a wooden mould drawn
along a straight-edge to guide the mould, acting like the carpenter’s
plane, when forming analogous mouldings in wood. When such cornices are
of sufficient size and depth to require it, wooden brackets, shaped
something like the profile of the cornice, are fixed up against the
wall, and laths are nailed on these brackets, to serve as a foundation
for the mouldings. By this means the necessity for a heavy mass of
plaster, to get the requisite projection in the cornice is avoided;
which mass would be unwieldly to manage, and liable to fall down by its
weight.
Foliage and ornamental work in plaster is made by modelling
the ornaments by hand, in a proper kind of clay, worked by steel or
wooden tools, resembling small spatulas in form. To do this requires a
taste and skill in drawing or designing in the workman, which raises
him to the rank of an artist. When the model is finished and dry, the
surface of it is covered with a thin coat of oil, and a mould of fine
plaster is taken from it in separate pieces. To allow of the plaster
mould being taken off the model, the edges of these separate pieces of
the mould are made smooth so as to fit accurately together. From this
mould any number of casts may be taken by pouring fluid plaster
into the mould when it is put together; and as soon as each cast has
set, or become hard,[Pg 150] the mould is taken off it, to be put
together again for a new cast. There has been recently an improvement
introduced, which leads to a diminution of the use of plaster for
ornaments; this is by the substitution of . The
material so named is formed chiefly of paper, brought to the state of
a paste, and then compressed in moulds. There is to every ornament so
made a counter-mould, following the general contour of the ornament, so
that the piece is made about equally thick in every part. The resulting
ornament is very much less ponderous than those made of plaster,
and much less liable to fracture. The interior decorations of many
buildings are now made of this material.
Whitewashing and Stuccoing.
Old plaster ceilings, walls, &c., are cleaned by being
whitewashed. The plaster is first washed over with clean water,
by means of broad flat brushes, to remove the dirt. All cracks and
defects in the plaster are then stopped by filling them up with
new plaster, and it is frequently necessary to cut away the plaster in
such places to obtain a clean new surface to enable the new plaster to
adhere. When the surface is dry, the whitewash, made of whiting mixed
up in water, is laid on with the same form of brushes, and two or three
times gone over, so as effectually to cover all stains and marks on the
surface. Instead of being whitewashed, walls are frequently coloured by
mixing ochre, of the proper tint, in the water along with the whiting.
The outside of walls of houses, &c., are now frequently covered with
stucco, a kind of plaster made with a lime that resists the action of
water, when set, and which, if well managed, causes the wall to look as
if built of stone. The mode of stuccoing walls is exactly the same as
that of covering them with common plaster.
Origin of Paper-hangings.
In early times, wealthy people were accustomed to have the walls of
their rooms covered with tapestry, which was a combination of
woven cloth and needlework, somewhat mid-way between the sampler
work and the carpet work of our own day. These specimens of
tapestry frequently represented some historical events, and were often
worked by the hands of the lady of the mansion and her maids; but at
other times were the work of men following that line of occupation.
The walls of those rooms which were not thus covered, were usually of
panelled wainscot, or oak.
[Pg 151]
But when tapestry went out of fashion, and a more lively covering for
a wall than oak was wished for, a custom arose of printing or stamping
certain coloured devices on sheets of paper, and of pasting those
sheets against the wall. We believe that it is in England more than in
any other country that this covering for walls is employed; and since
the removal of the duty which was formerly laid on paper-hangings,
they have become so very cheap as to be almost universally employed in
houses of every class; indeed, it may be regarded as a circumstance not
a little conducive to the comfort and neatness of humble dwellings,
that a yard of printed wall-paper can now be purchased for one
halfpenny. From this trifling price up to five or even ten
shillings per yard, paper-hangings are now manufactured; so great are
the improvements gradually made in the modes of manufacture.
The Manufacture of Paper-hangings.
It will be interesting to give a brief description of the mode of
making, or rather printing, paper-hangings, before we speak of the
employment of the paper-hanger; for all that devolves upon him is to
fix up the paper when printed.
The paper employed is a sort of cartoon or cartridge paper manufactured
for the purpose,—rough, but strong. Until recently, every piece of
such paper was stamped, and the excise duty paid on it, before the
process of printing commenced.
In general, the paper is printed in “distemper,” that is, in
colours mixed with melted size, but sometimes in varnish. The
pigments or colouring substances employed, are principally
these:—Red or crimson,—lake, vermilion, rose-pink,
and red ochre:—Blue,—Prussian blue, verditer, and
indigo:—Yellow,—Dutch pink, yellow ochre, and chrome
yellow:—Green,—verdigris, and various mixtures of the
blues and yellows just mentioned:—Orange,—vermilion,
or red lake, mixed with Dutch pink:—Purple,—a wash
made of logwood, and various mixtures of lake with Prussian
blue, or with indigo:—Black,—ivory black and lamp
black:—White,—whiting and white lead. There are other
substances occasionally used, according as improvements or discoveries
are made in the manufacture of colours; but various combinations of
those which we have mentioned will yield almost every tint that can be
desired.
These colours are mixed with water, together with a little size or gum,
by which the colours are made adhesive without being too stiff for
working. If the paper is to be glossy when completed, or if any one
of the colours with which it is[Pg 152] printed is desired to be glossy, the
pigment for that colour is mixed with oil of turpentine and certain
gums and resins which will give a glossy surface to the paint when
dry. Before the printing commences, the piece of paper (which is about
twelve yards long) is coated all over with that colour which is to
form the ground. Powdered whiting is mixed with melted size
to a proper consistence, and laid on with a large brush, in the same
manner as a ceiling is whitewashed: the piece of paper is then left
to dry. If the ground is to be white, nothing more is required before
the printing; but if it is to be coloured, a second ground is laid on,
made of melted size, and of such colouring substances as will give
the required tint: this, when dry, is the ground which is to receive
the ornamental pattern. If the ground is to be glossy, the colouring
substance is mixed with varnish, gum, resin, &c., instead of size and
water.
When the ground is thoroughly dried, the device is laid upon it, and
this is, in most cases, done by a process almost exactly corresponding
with wood-cut printing, in the fine arts. An impression is taken from
wooden blocks, which are cut in such a manner that the figure to be
expressed is made to project from the surface, by cutting away all
the other parts. But this raised device only represents that portion
of the whole figure which is to be of one colour; so that if
the pattern is to be ultimately represented in four colours, as is
frequently the case, there must be four differently-carved blocks or
stamps to represent these, and the blocks must be so carefully carved
with reference to one another, that though the sizes of them are all
exactly alike, the devices occupy different parts, and do not interfere
with one another: the whole beauty and correctness of the figures
depend on the accuracy with which the blocks are carved.
Suppose, now, that the paper is properly painted with the ground
colour, dried and spread out on a flat board,—the carved blocks ready
for use,—and the colours mixed and melted in a warm state,—the
process is then conducted as follows. A piece of leather or of oilskin
is stretched over a flat block, and a boy lays a coating of one of the
colours to be used—say green—on the leather, with a brush. A man
then takes that one of the carved blocks which is to stamp the green
part of the device, and lays it down flat on the wet colour, by which
a coating is transferred to all the raised parts of the block. This
is then stamped down, with a firm and steady pressure, upon the piece
of paper, by which the green device is permanently impressed. As the
carved block is only large enough to stamp a small portion at a time,
an adjoining portion of the long piece of paper is taken,—a fresh[Pg 153]
coating of colour laid on the leather by the boy,—this coating again
transferred to the carved block,—and again from thence to the paper.
This continues until the whole length of the paper is printed with the
green device, care being taken that the different impressions shall
accurately join one another at the proper parts.
The paper is then laid aside to dry, and preparations are made for
printing the second colour upon it.
Let us suppose this colour to be pink. The proper ingredients
are mixed with size, and melted, and a coating of this laid on a block
covered with leather, as in the former case. The proper carved block
is then taken, and an impression stamped by its means in precisely
the same manner as before, with the exception of the colour being
pink instead of green. But in laying the wet stamp on the piece of
paper, great care is requisite in adjusting the two colours so that
they shall not interfere with each other:—for instance, if the green
represents leaves and the pink represents flowers, it is important that
the pink should not, by a misadjustment of the second stamp, go over
a part already occupied by green, so as to give a confused mixture of
green leaf and pink flower at the same spot. If we closely examine
the pattern of paper-hangings on the walls of our rooms, particularly
the inferior papers, we shall frequently see instances of the bad
adjustment to which we here allude.
The pink stamping proceeds from end to end of the piece of paper, until
the whole is done; after which it is laid aside to dry. A process
precisely similar in every respect is followed with all the subsequent
colours, be they few or many. The more complicated the figure is, or
the greater the number of colours it contains, the greater is the
degree of care required in impressing the successive colours on the
papers. In order that no time should be lost, directly the workman
has taken a supply of colour on to his block, the boy lays on another
coating on the leather. Indeed, the whole process very much resembles
the rudest kind of printing, with the exception of the use of
different colours.
The description we have here given is such as will afford a general
idea of the nature of the process. Various improvements have been from
time to time introduced for facilitating the printing; but it is hardly
necessary to dwell upon them.
Stencil, Washable, and Flock Paper-hangings.
In some of the cheaper papers, the preparation of the carved wooden
block, and the time and attention necessary in[Pg 154] using them, would
be incompatible with the charge made for the finished article: an
alteration is therefore made in the mode of proceeding. The principal
outline is printed on the paper by means of a carved block in the usual
way; but the remaining colours are put in by stencilling. A
stencil, or stencil-plate, is a piece of leather, oil-cloth, or thin
sheet metal, with any required device cut in it. Such a stencil is laid
down flat on the paper, and is covered with the required colour by
means of a brush. This colour of course passes through the holes in the
stencil, and falls on the paper, while the uncut parts of the stencil
prevent the colour from falling on any other part of the paper. A
device is thus painted on the paper in a much easier manner than by the
use of a carved block. But from the nature of the process it is found
that the delicate parts of the pattern cannot be represented by this
means, as it is difficult to ensure the passage of the colour through
small perforations. But for the purposes to which stencilling is
applied—viz., the preparation of cheap paper-hangings, this delicacy
is not required. One or more carved blocks are used with the stencil
plates according to circumstances, the choice between blocks and
stencils depending both on the nature of the pattern, and on the value
of the paper when finished.
Some of the more costly kinds of paper-hangings have gold as one of
the materials forming the device. This is effected by using a wash of
gold powder, instead of a pigment, on one of the carved blocks. There
are also washable paper-hangings, in which the surface is of
a glossy or varnished nature, by which it may be washed free from
dirt and grease without removing the colours with which the paper is
printed. There is likewise a kind of paper-hangings called flock
paper, which has been much in use, and of which the following
description has been given.
The flock is woollen cloth reduced to great fineness, and laid on
with varnish. After the coloured portions of the paper are finished,
a carved block representing the device which is to be flocked, is
laid down on a flat place coated with wet varnish, and an impression
of the varnish is transferred to the paper, just as if it had been a
coloured pigment. A quantity of the powdered flock is then strewed over
the whole paper, and pressed on it by a flat board, a roller, or some
other convenient means. The paper is then left to dry, after which the
dry flock is brushed off from those parts where no varnish had been
applied, leaving an appearance much resembling that of coarse woollen
cloth, which our readers may frequently have noticed. The flock is
prepared in various ways. Sometimes pieces of woollen cloth of the[Pg 155]
proper colour are taken, and chopped up by means of a bill or knife;
but this is a rude and imperfect way, now probably out of use. Another
mode is, to place the pieces of cloth in a flat box, and cause a sharp
knife, moved by machinery, to pass rapidly, with a chopping motion in
every direction over the various pieces of cloth. In some cases, also,
the cloth is reduced to flock by a kind of grinding process.
The Process of Paper-hanging.
This, then, is an outline of the mode by which paper-hangings are
prepared; and we must next speak of the method of pasting them against
the walls of a room. As the long pieces or strips of paper do not
average more than two feet in width, it is obvious that a great many
joints must be made in covering the side of a room with paper. These
joints proceed not crosswise, but perpendicularly from the ceiling
downwards; and considerable care is necessary to insure the continuance
of the pattern on the two sides of a joint: it is in this that the
principal art of the paper-hanger consists.
A strip of printed paper twelve yards long is called technically a
piece. This piece has ragged unfinished edges, and the edges
are to be cut away in a straight even line until a proper part of
the pattern is reached; for the blocks are so carved, that one edge
always corresponds exactly with the opposite edge. The wall, which
is generally plastered, is washed or sized, and made fit to receive
the paper. The cement with which the paper is fixed up is thin paste;
and when that paste is ready, the paper-hanger proceeds as follows.
Supposing the height of the papered part of a room to be twelve feet,
he cuts on four yards from his piece of paper, with the two ends
accurately at right angles to the long edges. He then lays it down on
a flat board or bench, face downwards, and coats the whole of the back
of the paper with liquid paste, by means of a brush. He then slightly
folds the paper over, so as to prevent it from dragging on the ground,
and, mounting a ladder or a pair of steps, applies one end of the paper
to the upper part of the wall, close to the cornice: then, by letting
the paper unfold itself, it falls to its full length, and extends down
to the bottom of the room, close to the wall. The workman has now
to judge, by the eye, whether the edges of the paper are perfectly
vertical, for the whole beauty of the work depends in a great measure
on this circumstance. When he has ascertained that the paper hangs
perpendicularly, he proceeds to press it firmly to the wall, by means
of cloths; and the paste has so far softened[Pg 156] the paper, that wrinkles
of every kind disappear. This done, he cuts off another piece twelve
feet, or four yards long, and pastes it against the wall in precisely
the same manner. But here great precautions are necessary; for the
workman has to attend to three particulars in fixing the second piece
by the side of the first:—to cause it to hang vertically,—to make
an accurate joining of the pattern,—and to refrain from soiling the
surface of the first piece by the paste of the second. All these are
precautions which can only be properly attended to after considerable
practice.
When the workman is approaching an angle or corner of the room, he
must cut his paper to such a width as will just reach the corner, for
it is generally difficult to bring the paper round both sides of the
angle. In the case which we have supposed, the height of the room is
just one-third the length of the piece of paper, so that there need be
no joints at any intermediate part of the height. But if the height
were any other amount,—say ten feet—three pieces of that length would
leave a fourth only six feet long; and as such a piece is not likely to
be wasted, it follows that there must be a joint at some intermediate
point between the floor and the ceiling. Such a joint requires especial
care, as the pattern has to be attended to both in a vertical and a
horizontal direction.
When the side of a room is broken by recesses, projections, &c., a good
workman will so arrange his pieces of paper as to give a symmetrical
appearance to the two sides of a projection of a recess, so that the
same part of the pattern which comes to the right hand edge shall also
be seen at the left hand. In papering a staircase, when the upper and
lower edges are oblique and not horizontal, it is of course necessary
that the ends of the paper should be cut in a corresponding manner, in
order that the long joints should be vertical.
As it is difficult to bring the ends of the paper precisely to the
cornice at the top and to the skirting-board at the bottom, it is usual
to hide those ends by pasting a narrow strip of paper along the top
and bottom of a room, which gives a neat finish to them. This strip of
paper is printed in colours with some pleasing device; and as a broad
piece is printed as quickly as one two or three inches wide, it is
customary to carve a block with twelve or twenty repetitions of the
same narrow pattern, side by side; so that the whole are printed on one
sheet. The paper-hanger has therefore carefully to cut the strips one
from another, and paste them round the wall at the parts which we have
mentioned, and sometimes up the corners of the room likewise.
It is sometimes preferred, instead of papering the walls of[Pg 157] a room, to
stencil them. In this case the plaster of the wall is prepared
in a smooth manner to receive the distemper colour, and the pattern is
stamped or printed on the wall in a manner almost exactly the same as
that which we have described respecting stencilling paper-hangings.
This mode is not susceptible of so much neatness as the use of printed
or stamped paper, and is only employed for common apartments.
There is occasionally a kind of work which falls into the hands of the
paper-hanger very different from those we have mentioned—viz., fixing
gilt wood mouldings round the top and bottom of a room, instead of
pasting a paper bordering in the same place. What little we shall have
to say on this subject will be contained in the following chapter.
[Pg 158]
Chapter X.
THE INTERIOR—PAINTING AND GILDING.
Reasons for Painting a House.
The love of neatness and elegance which distinguishes the cultivated from the rude man in the decoration of his dwelling, is not the only motive for these interior fittings of a modern house. There are in many instances manifest advantages, in relation to dryness and durability, resulting from such arrangements. Such is the case with respect to one of the two processes which will occupy the present chapter. In noticing the services of the house-painter, it will be found that they are conducive to something more than our love of colours and tasteful decoration, for they greatly promote the durability of wood and iron work. Wood of almost every kind is liable to injury from the effects of the atmosphere, if left unprotected; but when coated with oil-paint, its power of resisting those effects is much increased. Cleanliness is also more easily preserved where paint is employed. If a room door, for instance, were not painted, it would require the same scouring and cleaning which an uncarpeted floor so often receives, though perhaps not so frequently. When we consider, therefore, that durability, cleanliness, neatness, and pleasing decoration, are all derived from the judicious employment of oil-paint in a house, we shall conclude that a painter renders important service in the preparation of a dwelling-house.
Materials used in House-painting.
House-painting, in most cases, consists in laying on several coats
of some mineral substances mixed up to a fluid consistence with
oil. There is no other liquid body which is found to have so
many advantages for this purpose as oil; for although turpentine, milk,
beer, spirit, and other liquids are occasionally employed, oil is
the standard material with which the colouring substances are mixed.
The colouring substances, as well as the oils, employed in painting,
are very numerous; and we can only offer a brief description of the
principal among them.
White lead is the most valuable of all the colouring bodies,
since it enters into the composition of almost every other. It is
made by exposing sheet-lead to the action of vinegar, by which a
white substance is procured. Bougival white, and[Pg 159] Spanish
white, are mineral substances procured from abroad. Chrome
yellow, Turner’s yellow, Massicot, Naples
yellow, King’s yellow, Orpiment, and Ochres,
are various bodies of a yellow colour, some derived from earths,
others from ores, and others from chemical treatment of metals.
Vermilion, Carmine, Cochineal lake, Madder
lake, Red lead, Indian red, Venetian red, &c.,
produce various tints of red and crimson; but the materials themselves
are derived from very different sources. Vermilion is a compound of
sulphur and mercury; Carmine and Cochineal lake are prepared from
an animal substance; Madder lake from a vegetable; Red lead is an
oxide of that metal; while the others are derived from various kinds
of earth. For a blue colour, the painter employs Prussian
blue, which is a compound of prussic acid and iron; Indigo,
derived from a plant growing in the East Indies; Blue Verditer,
a nitrate of copper; and some other substances. Most green
paints are made of salts of copper, such as Verdigris, which
is an acetate of copper; Scheele’s green, an arseniate of
copper; Green Verditer, a nitrate of copper, and Brunswick
green, a muriate of copper; together with two or three earths,
such as Italian green, Saxon green, &c. Browns
are generally produced by a mixture of black and red;
but there are several earths which yield a brown colour. These are the
principal colouring materials employed by the house-painter, for almost
every intermediate tint or grade of colour can be produced by mixtures
of two or more of the above-mentioned materials, in certain proportions.
The liquid principally employed to mix with these dry colours is
Linseed oil. This is obtained by beating, pressing, or heating,
from the seed of the flax plant, the , which
grows in most parts of Europe. This oil has so much fatness
or unctuousness, that it would dry with extreme slowness were not
some further precautions taken. It is boiled with litharge
and white vitriol, in certain proportions, by which it has
a drying quality imparted to it. Nut oil is sometimes used
in painting: this is procured from the kernels of walnuts, beech
nuts, hazel nuts, and other kinds of nut, by a process similar to
that by which linseed oil is obtained. Oil of turpentine, or
turps, is largely used by painters, as it has a drying quality
which counteracts the fatty nature of linseed oil, in combination with
which it is generally used. It is obtained from a liquid or sap exuding
from a species of pine tree, in North America: the sap is crude, or
common turpentine; and by a process of distillation, the oil of
turpentine is obtained from it, leaving a substance behind which
constitutes yellow resin. Oil of spike, oil of lavender,
and oil of poppies, are sometimes used by the[Pg 160] painter; but
not very frequently, on account of their expense; they are vegetable
preparations. Pilchard oil, (obtained from the fish,) common
tar, coal tar, and oil of tar, are used occasionally
for rough exterior work. Varnish, size, beer,
milk, and one or two other liquids are used to a small extent
in some processes to which the painter has to direct his attention.
Varnishes are mixtures of various resinous bodies with spirit; and size
is a jelly obtained by boiling parchment, leather, parings of hoofs, or
of horn, or some similar animal substance, in water.
Preparing the Paint.
Such being the principal materials from which the painter prepares
his paint, we proceed to speak of the mode by which he mixes them.
The colours are mostly purchased in that form which is called dry
colours, that is, in coarse powder or small lumps; and they have
to be reduced to fine powder before they are mixed with the oils, &c.
If they contain gritty particles of sand, &c., the colour is put into
a tub or pan, and water thrown upon it, and mixed up with it. The
gritty particles soon fall to the bottom, and the remainder is poured
into another vessel, where, in a short time, the colouring substance
falls to the bottom, and can be obtained by pouring off the water;
after which the powder is dried. But if the substance is one which will
dissolve in water, or if it is not very gritty, it is ground up to
powder in a dry state.
When the substance is reduced to fine powder, the painter begins to
incorporate the oil with it. He has a grindstone of marble or
porphyry, on which he places a small quantity of the dry colour, and
moistens it with a little oil. With a large flattened pebble, called
a muller, he then grinds up the powder with the oil, until
both form a perfectly smooth paste. That portion is then removed
by a palette knife, (which is a broad thin knife,) and placed in
an earthen paint-pot. Another small portion of powder and oil is
ground up in a similar manner, and put into the paint-pot; and so on,
until a sufficient quantity has been obtained. When this is done,
the pot contains paint, which is too thick for use; to liquefy it,
therefore, a given quantity, which is determined by experience, of oil
or turpentine, or a mixture of both, is added, until the paint has
acquired a consistence—thick enough to prevent it from running into
drops when laid on the work—and thin enough to make it work with ease.
The Process of Painting.
Supposing the carpenter to have left the doors, the windows,[Pg 161] &c., in a
clean and smooth state, the painter’s first office is knotting.
Knots are round places in a plank, in which the grain of the wood runs
through the thickness of the board, so as to show the ends of the pores
at the surface. These ends absorb a greater quantity of paint than the
other portion of the wood, so that if the same number of coats were
given to all alike, the knots would have an ugly, dead appearance,
in consequence of the absorption. The painter, therefore, gives the
knots more paint than the rest of the wood-work; and the preparatory
coat, which is laid on the knots only, is called the knotting.
The paint used is generally red lead, and boiled oil; or sometimes
red lead and size. When this knotting is dry, the priming is
applied, consisting of a thin coat of white paint. White is used for
the priming under almost every variety of circumstances, whatever the
subsequent colours may be. This white paint is a mixture of white
lead, linseed oil, and oil of turpentine, and is laid on, as are the
subsequent coats, by means of brushes which are too well known to need
a lengthened description. They vary from a quarter of an inch to three
inches in diameter, and are generally made of hog’s bristles bound
round with string, or sometimes with tin.
When the priming is dry, the painter proceeds to fill up all the nail
holes and other irregularities, with putty. This he does by means
of a pointed knife, with which he works in small portions of putty
wherever they may be needed. It is then ready for the second coat of
paint, which is thicker than the first, generally white, but sometimes
coloured. Painting appears to be a very easy process, but in common
with other trades, it requires considerable practice before skill
can be attained. After having worked the brush over the wood-work in
every direction, so as to completely cover every part with paint, the
“laying-off” is effected by drawing the brush smoothly over every part
in the direction of the grain, particularly at the stiles and panels
of doors. Brushes of various sizes are employed, by means of which the
workman can paint the fine mouldings, beading, &c., as well as the
broader surfaces. The more skilful the workman is in the use of his
tools, the less do the marks of the brush remain visible when the work
is done.
As each coat of paint dries, another is laid on, until sufficient has
been applied. The number varies from two to seven, according to the
part which is to be painted, and the means of those who have to pay
the painter; but in general, four coats is the average quantity which
new wood-work receives. It is the last two coats only which are of
the colour selected, as those which are preparatory are seldom[Pg 162] other
than white. On some occasions it is desired to have the last coat
glossy; but in others dead. To effect these differences,
all that is necessary is, to vary the oil with which the colour is
mixed. If a glossy surface is required, linseed oil is principally
used; but if a dead surface, oil of turpentine predominates. It is
frequently seen that the walls of staircases, and other large surfaces,
are, when finished painting, totally without gloss. This is effected
by what is called flatting, that is, a coat of paint mixed
wholly with oil of turpentine: the turpentine soon evaporates, and
leaves the colour without gloss on the walls; whereas, when linseed
oil is employed, the oil dries and hardens, instead of evaporating,
and assumes much of the character of a varnish. If no linseed oil is
employed in flatting, it is called a dead flat; but if a little
is added, in order to produce a faint gloss, it is called a bastard
flat. This part of the work forms one of the most unwholesome in
which the painter is engaged, since the oil of turpentine, which is
constantly evaporating during the process, is found to be extremely
prejudicial to health.
As we are here speaking of a new house, we need not detail the
process followed in repairing an old one. Nor is it necessary so to
do even in respect of the processes themselves, for they are nearly
the same for old work and new. The principal points of difference
are these:—that in old work, greasy and dirty spots are washed with
pearl-ash and water, or with turpentine; that the old paint is rubbed
smooth with pumice-stone, or, if very rough, burned off; that a smaller
number of new coats of paint will suffice; and that a larger proportion
of turpentine is used than in new work.
Graining and Marbling.
We have in the above details confined our attention to that more
general and economical kind of house-painting in which a large surface
is painted of one uniform colour. But the department of house-painting
in which the taste of the workman is more fully developed, is that in
which imitations of various species of wood and marble are attempted;
these processes are called graining and marbling. We may
perhaps call this a humble branch of the fine arts, since the
workman prepares a picture of a piece of wood or of a slab of
marble; but whether this be a correct term or not, it is certain that
skill in this branch depends more on taste and observation than on
fixed rules.
Graining and marbling are sometimes done in oil-paint, but more
frequently in distemper, that is, with a colour mixed with beer
or some other liquid more limpid than oil;[Pg 163] in this latter case, as the
graining would not have a durable character, it receives one or more
coats of varnish. We will endeavour to give a general idea of the mode
in which graining and marbling are effected.
The kind of wood usually imitated in this way is oak, or
wainscot, as it is more generally called. When this is imitated
in oil, the last coat of paint previous to the graining is made of
rotten stone, white lead, and linseed oil, and is of a light oak
colour. On this is laid the graining colour, which painters call the
megilp, and which is a thin paint composed of oil, rotten
stone, sugar of lead, and white wax. When this has set a little, the
painter draws over the surface the teeth of a kind of comb, called
the graining comb, by which an imitation of the grain of oak
is produced; these grained lines, to make the imitation more close,
are drawn in a wavy direction. The workman then wraps a little piece
of leather round the finger, and delicately wipes off the colour from
small spots of various forms, by which the light parts of a piece of
oak are imitated. In this state, the grain and the light parts have
rather a harsh appearance, to remove which, a soft dry brush is worked
over the whole in such a manner as to make the various parts blend with
one another. A little Vandyke brown is then mixed up into a smooth
paint, and with this the dark veins are imitated, by means of a small
brush or pencil.
But in graining oak in distemper, the graining colour consists of other
materials; many receipts are given, but one is Vandyke brown, burnt
umber, and raw umber, mixed into a paint with beer or ale. This is laid
on with a brush, and the subsequent processes of producing the grain,
the light patches, the dark veins, &c., are much the same as in oil
graining, with this exception, that the grain is produced by veining
brushes, instead of graining combs. When the whole is dry,
it receives one or two coats of varnish, to act as a preservative.
By processes very similar to that just described, mahogany, rose-wood,
satin-wood, maple, pollard oak, zebra-wood, walnut-wood, elm, and other
species of wood, are imitated. For mahogany, the ground is Venetian red
and white lead, and the graining colour is Sienna, or Vandyke brown,
ground in beer. For rose-wood, the ground is lake, vermilion, and
flake white, and the graining colour Vandyke brown, ground in ale. For
satin-wood, the ground is the same as for light oak, and the graining
colour is Oxford ochre, ground in ale. The other kinds of wood are
imitated by grounds and graining colours more or less resembling those
now mentioned. The manual use of the tools is more difficult for the
variegated woods than for oak. Satin-wood, and some other[Pg 164] kinds, have
large spots or patches of a lighter colour than the rest of the wood,
and of a peculiarly soft appearance; these are imitated by letting a
sponge fall on various parts of the wet graining colour, by which some
is wiped off, and the edges of these parts are then softened by means
of a badger-hair brush, called a soft even, which is drawn
lightly across the light and dark parts, whereby the sharp edges are
softened and blended.
The imitation of marble is effected in a similar manner to that of
wood. For white marble, or rather, that which is slightly marked with
dark veins, the walls are first whitewashed, and then washed with
whiting and milk, to obtain a fine white surface. Lamp black, damp
blue, Indian red, and some other colours, are then laid on with very
fine pencils or brushes, in fine but irregular lines, so as to imitate
the veins of the marble. Sienna marble has a ground of yellow
ochre; Florentine marble, one of white, black, and Indian red;
dove-coloured marble, one of light lead colour; and black
and green marbles have the colours designated by their names.
On these grounds are pencilled the light and delicate veins traversing
the surface in every direction, according to the colour and character
of the veins in the marble to be imitated. There are then various
contrivances made use of, by which a softness is produced in all
the veins; this is of more importance in marbling than in graining,
since much of the beauty which we acknowledge to exist in marble is
undoubtedly due to the exquisite softness with which its colours are
blended. The kind of marble called porphyry is imitated in a
singular manner. This marble is spotted all over in various colours;
and the imitation is therefore spotted. A ground is laid on of the
proper colour, and a brush is dipped into a mixture of vermilion and
white, and after being allowed to drain nearly dry, is struck against
a piece of wood, by which a sprinkling of small spots falls on the
surface. The brush is then dipped into another colour, and a similar
process gives a second sprinkling. This is done a third and sometimes
a fourth time, according to the colours of the spots in the marble to
be imitated. The mica, quartz, and feldspar, in granite, are sometimes
roughly imitated by similar means.
Whatever be the kind of marble which is imitated, it is varnished after
the marbling is completed, in order both to give it greater durability,
and to imitate the beautiful polish which can be imparted to marble.
Gilding, as an Interior Decoration.
Supposing the internal decorations to have proceeded thus[Pg 165] far, we
may next say a few words about the costly material gold, as
applied in furtherance of these embellishments. This is only of limited
application, and in the better class of houses; but as gilt mouldings
frequently form the finishing part of the papering of a room, and as
the houses of most persons contain some articles which are gilt, we
will give a slight description of the processes followed by the gilder,
but without reference to any particular article of furniture,
since that is a department into which we do not profess to enter.
A metal gilder, or water gilder, is a different workman
from the carver and gilder, who gilds various articles of wood
or composition. The former lays a thin coating of gold on articles of
metal, by means of mercury and of heat, an employment of an extremely
unhealthy character. The carver and gilder lays a surface of leaf-gold
on ornaments, frames, or mouldings, made of wood, plaster of Paris,
papier-maché, or composition.
If the gold were laid on the bare material by any sort of gum or
cement, it would not adhere permanently, nor would it have that
brilliancy of appearance which the natural lustre of the metal is
calculated to produce; above all, that dazzling surface, known as
burnished gold, could not be so produced. The gilder, therefore,
lays on a certain thickness of such substances as experience has taught
him will answer the proposed end. There are, doubtless, many substances
which would answer for this purpose; but the course which is actually
adopted we proceed to describe.
The Process of Burnish-Gilding.
We will take, as an instance, a long piece of the moulding which the
paper-hanger applies in the way to which we have alluded. This is cut
out to the proper hollow or reeded form by a carpenter, who employs
planes suited for the purpose. The wood which he uses is of a kind
tolerably free from knots and holes: and when the moulding is ready,
it passes into the hands of the gilder. The first thing done is to
wash it with a mixture of whiting and parchment-size, made quite hot,
and almost as limpid as water. The size used for this and for other
purposes required by the gilder, is obtained by boiling cuttings of
parchment in water until a stiff jelly is produced.
When the moulding is dry from the application of this preparatory
wash, any small holes that may exist are stopped up with putty, and
the moulding is ready to receive five or six coatings of a very thick
mixture of whiting and size.[Pg 166] Those coatings are laid on moderately
warm, by means of a brush, each coat being thoroughly dried before the
next is applied. By this means the moulding is coated to the thickness
of a sixteenth or twelfth of an inch, by which the fine squares and
hollows produced by the plane (if there happened to be such in the
moulding) would be liable to be stopped up: to prevent this, modelling
tools of various forms are drawn along the wet whiting, so as to
preserve the original pattern in tolerable condition. The whole surface
is then smoothed by small pieces of pumice-stone worked to fit the
various parts of the moulding. The stones and the whiting being kept
constantly wetted, and the former worked steadily over the latter, a
smooth and even surface is attained.
When the moulding is dry after this smoothing process, it is further
smoothed with sand or glass paper, and is then coated with five or six
layers of burnish gold size. This is a very peculiar composition
of suet, black lead, clay, parchment-size, and other ingredients, mixed
to a stiff consistency. These successive coats or layers are well dried
after each application; and after one or two other processes by which
the gold size is rendered smooth, the moulding is ready to receive the
leaf gold.
Gold, in the form in which it is thus used, is one of the thinnest
substances which the art of man has ever prepared in a solid form,
since it would require more than a quarter of a million of the small
sheets into which it is beaten, to make a pile one inch in
thickness. A solid piece of gold is rolled into the form of a ribbon by
means of a flatting-mill: and the gold-beater then reduces it to the
thickness—or rather thinness—to which we have alluded, by means of
hammering.
The gilder receives this leaf gold in the form of sheets or leaves
about three inches square, inclosed between the leaves of a small book.
He blows out some of these leaves on a leather cushion surrounded by a
parchment border on three sides; this border, is to prevent the gold
from being blown away, the fourth side being left open for the future
proceedings of the workman. The gilder supports the cushion on his left
hand, and with a knife in the other, he takes up one of the leaves
of gold, and by dexterous management, spreads it out smoothly on the
cushion. He then considers the width of the moulding, (which is laid
before him,) and determines how he can best cut up the leaf of gold so
as to adapt the pieces to the width of the moulding:—if for instance
a slip one inch in width will cover the width of the moulding, he cuts
the leaf into three equal pieces. He is next provided with a flat
camel-hair brush, called a tip, the hairs of which are from one
to two inches in length, and laid parallel with great regularity.
[Pg 167]
His tools being thus ready, he wets a small portion of the moulding
by means of a camel-hair pencil dipped in water, and, taking the
tip in his right hand, he lays the hairs on one of the slips of
gold, which slightly adheres to it. This slip of gold he transfers to
the moulding, where it instantly adheres by means of the water with
which the latter is wetted. Another portion is wetted in a similar
manner, and another slip of gold laid on, one end of which is made to
lap a little way over the one first laid on. A third slip is now laid
on in a similar manner; and by this time the first leaf of gold is all
used. A second is therefore laid out smooth by means of the knife,—cut
into three pieces,—and laid on the moulding as before. This process
continues until the moulding has been gilt in its whole extent. We may
remark, that the moulding is placed in an inclined position, the higher
end being first gilt: this is done in order that the water should
gradually flow off from beneath the pieces of gold after they are laid
on, to facilitate the drying.
When the gold—or rather the wetted gold size which is beneath it—has
attained a certain degree of dryness known only by experience, and
which occurs in a time varying from one to twelve hours according to
the state of the atmosphere, the gold is burnished by means of
a burnisher made of flint, agate, or bone. This, if carefully done,
produces a brilliant gloss, but could not be at all attained without
the layers of whiting and gold size under the gold. Sometimes a portion
of the moulding is preferred, for relief and contrast, to be left dead
or matt, as it is termed. In this case the burnisher is not
used; but the gold, after it is dried, is merely secured by a thin
clear cement or varnish of parchment size.
The Process of Oil-Gilding.
Sometimes no burnishing at all is required, while a degree of
durability which cannot be conveniently obtained with burnish-gilding
is desired. In this case the moulding is gilt in oil gold, by a
process differing in many respects from that which we have mentioned.
For oil-gilding a ground of whiting and size is required, as in
burnish-gilding, but not in so great quantity. After the application of
a few coats of whiting and size, the moulding is smoothed in the manner
before described; and in some cases a few coats of burnish gold size
are applied, but not always. The next process is to wash the moulding
with two or three coatings of strong size, by which it acquires a gloss
somewhat similar to that produced by varnish, and which has[Pg 168] the effect
of preventing the absorption of the substance next employed.
The moulding is now ready to receive the oil gold size, which
is an exceedingly smooth mixture of ochre and oil. This is laid on in
a stratum as thin and smooth as possible; and after being set aside
for some hours, it acquires a peculiar degree of clamminess between
wet and dry; when it is ready to receive the coating of gold. The gold
is blown into the cushion, spread out, cut into slips, taken up by the
tip, and applied to the work, in the same manner as in burnish-gilding;
but the moulding is not wetted with water, the partially dry oil gold
size serving that purpose. The gold is, in this case, pressed down into
the hollows and crevices of the moulding, by means of a piece of cotton
wool; and when the whole is gilt, a soft brush is lightly applied,
by which the gold is worked into small depressions, which it would
not otherwise have reached, and the superfluous gold is rubbed off.
The gold is now left as it is, or is washed with transparent size, or
receives a coat of varnish. In either case it becomes in a short time
so far hardened as to be susceptible of washing without being rubbed
off.
Gilding Enriched Ornaments.
The description which has been given of the process with reference to
the mouldings used by the paper-hanger will also apply to most other
articles with which the gilder is concerned. But in proportion to
the elaborate nature of the article must be the care bestowed by the
gilder. This particularly applies in the case of an elegant carved
looking-glass frame.
The richly ornamented frames, window-cornices, mouldings, &c., which
form a great part of the work of the gilder, are in general not carved
in wood, but are cast in moulds, and are made of a tough and durable
composition formed principally of glue and whiting. The ornaments,
when cast, are fixed on wood frame-work or foundation, and in that
state pass into the hands of the gilder. His mode of treating them
is somewhat different from that required by a straight plain piece
of moulding:—the material itself does not require so many layers of
whiting and size as those articles which are made wholly of wood; and
the difficulty of smoothing intricate and ornamental surfaces renders
many precautions necessary.
Sometimes the cornice of a room, or a portion of it, and also the
central ornament of the ceiling, are gilt. This is generally done in
oil gold; and as the material of which they[Pg 169] are made, viz., plaster of
Paris, very much resembles whiting, scarcely any of the last-mentioned
substance is required to be applied by the gilder.
We may here state, in connexion with what has been said about gilt
mouldings for rooms, that the paper-hanger fixes them to the wall by
means of broken needles, or headless brittle needles made for the
purpose. The pieces of moulding are cut to the required length, and
mitred, so as to join accurately at the corner; after which they are
fastened to the wall by driving in some of the needles at distances of
two or three feet.
[Pg 170]
Chapter XI.
A MODEL DWELLING-HOUSE.
The late Sir John Robison’s House at Edinburgh.
The various contrivances for rendering a dwelling-house complete in all
that respects the comfort of the inmates, could not perhaps be better
illustrated than by taking some actual instance, and showing what
has really been effected. The late Sir John Robison, an enlightened
man of science at Edinburgh, erected a house in the north-west part
of that city, and fitted it up with a care which has been rarely
observed in other places. So much has this house been regarded
as a model, that a full description of it has been given in the
Supplement to Loudon’s ; and we propose to give an abstract of such portions
of this description as can be understood without the aid of elaborate
drawings.
The distribution of the internal space of the house is so managed,
that, with the exception of two partitions in the first chamber-floor,
which cross the floors without resting on them, all the internal
walls reach from the foundation to the roof. The two partitions here
mentioned are of stone, and are supported on cast-iron beams isolated
from the floors, the joists of which are supported by wooden beams
placed alongside, but not connected with the iron beam. The movements
of the flooring, therefore, are not communicated to the partitions, and
do not consequently affect them by vibration.
The arrangement of the rooms, staircases, and passages, has especial
reference to the ventilation of the whole house. While the mass of
air in the rooms and passages is constantly undergoing renewal by the
escape of the vitiated air above, and the admission of large supplies
of fresh air from below, no currents are perceived in the apartments,
which, even when crowded with company, and amply lighted, preserve a
remarkable degree of freshness. Cylindrical flues of earthenware, nine
inches in diameter, are built into the gables, in close proximity to
the smoke flues of each room; and the lower ends of these ventilating
flues open into the spaces between the ceilings of the respective rooms
and the floors of those above them; and there is one or more of these
exit air-flues in each room, according to its size and use. The heated
and vitiated vapours pass upwards through the ceiling by a continuous
opening of about one inch and a half wide (behind[Pg 171] one of the fillets
of the cornice) all round each room; and having thus passed into the
space between the ceiling and the floor immediately above, they ascend
by the flues in the wall, and are discharged by them into the vacant
space between the ceilings of the attics and the roof, from whence they
find their way through the slates to the open air. The passage for the
air through the cornice is not visible from the floor of any of the
rooms, an ornamental moulding being so arranged as to conceal it. The
air flues are made to terminate above the ceilings of the attics, and
below the roof of the house, rather than at the chimney heads, in order
to prevent the possibility of smoke being over brought down by reverse
currents; and an advantage is likewise gained in protecting the attic
story from the cold which would otherwise be communicated from the roof
during winter.
The continued supply of fresh air to the lower part of the house,
to replace that which is carried off by the ventilators and by the
chimneys, is brought in from the garden behind the house by a passage,
the sectional area of which is eight square feet. The cold air admitted
by this passage (or by another similar one from the front of the house)
is made to pass over a stove in a lower chamber having a surface of
nearly ninety square feet, so that a temperature of from 64° to 70°
Fahr., can thus be imparted to the air. In very cold weather, 70°
is occasionally given to compensate the cooling effect of the walls
and glass windows, so as to preserve an equable temperature of 60°
throughout the house; but the usual temperature of the air issuing from
the stove is as low as 64°. The whole of this air is discharged into
the well of the staircase, which forms a reservoir from whence the
rooms draw the quantity required to maintain the upward currents in the
chimneys and in the ventilating flues. The air in the staircase finds
its way into the apartments by masked passages, of four or five inches
wide, and four feet long, over the doors, and by openings an inch in
width left under each door. The sectional areas of these passages are
more than equal to the areas of the chimney and ventilating flues;
there is, therefore, no rarefaction of the air within the rooms, nor
any tendency of the external air to enter at chinks of windows or other
irregular apertures. The course of the air, from the great aperture
over the stove, through the staircases, over and under the doors, into
the rooms, thence through the ceilings, and upwards by the escape
flues, forms a continuous series, in which all the air for all the
rooms comes from one central point, and is raised at that centre to the
precise temperature required. The quantity of escape is regulated by
hand, by means of throttle-valves at the mouth of each escape[Pg 172] flue;
hence, by opening or shutting each throttle-valve, the rate of the
ventilating current is augmented or diminished.
The kitchen is ventilated on the same principle as the upper rooms. One
flue proceeds from the ceiling over the fire-place, and another from
over a gas-cooking apparatus. The first of these is built in the gable,
close to the smoke flue; and the second passes up near the back of the
water cistern, so that the constant ascent of the warmed air may by its
vicinity prevent the water in the cistern from freezing in the winter.
The house is lighted by gas in every part; but no offensive vapour
or inconvenience of any kind appears ever to be felt from it. The
distribution pipes are of greater diameter than are generally employed,
and the pressure or current is thereby so equalized, that no sinkings
or flutterings of the flame are caused by the opening and shutting
of doors. The forms and proportions of the Argand burners and glass
chimneys are also so arranged as to effect nearly a maximum development
of light (of an agreeable hue) from the gas, and to prevent any
disengagement of sooty vapour; and the white and gold ceilings of the
drawing-room are said to attest the complete success with which this
latter object has been attained. The mirrors over the chimney-pieces
have statuary marble frames, and each chimney-piece has two gas lights.
But the use of gas in the kitchen is perhaps the most remarkable. Here
there is a gas-cooking apparatus. In the application of gas for
cooking, the arrangements are generally as follow:—A metallic ring,
pierced on its upper side with a great number of holes of very small
size, is attached to the pipe communicating with the gas main, and is
placed within a double drum or cylinder of iron, raised an inch or two
from the floor on short legs. This double cylinder is so constructed
as to leave a space between the inner and the outer cylinder of about
two inches; and in this space near to the bottom, the pierced ring is
fixed. A stop-cock in the pipe connecting the pierced ring with the
gas main shuts off the supply of gas when the stove is not in use. On
opening the cock, and applying the gas to the pierced ring, a brilliant
ring of flame is immediately produced, which soon heats both cylinders.
The air within the inner cylinder ascends into the room, which it
helps to warm; the outer surface of the outer cylinder also performs a
similar service; while the space between the two cylinders contains the
products of combustion, which are allowed to escape into the room, if
the heating power of the whole is required; but which are carried off
by an inclosed channel, if it be wished to protect the air of the room
from deleterious mixture.
[Pg 173]
In this house, the gas-cooking stoves are eight in number, the mouth of
each being four inches in diameter, a size which experience has shown
to be the most useful. The kitchen fire-place is no larger than is
requisite for roasting; all the other processes being performed either
in the oven, the steaming vessels, or at the gas stoves. These stoves
are placed in the bay of a large window, thus giving the cook the
advantage of a good light above the level of the pans. A close boiler
at the back of the grate affords steam for the cooking utensils and for
a hot closet; it also contains a coil of iron tubing, through which the
water of a bath, placed in a dressing-room on the chamber floor, is
made to circulate when a hot bath is wanted.
The flues for carrying off heated vapours, &c., are of two kinds.
It has already been stated, that the vitiated air of the rooms is
convoyed by apertures just below the ceiling into pipes which find an
exit at the top of the house. These flues are made of cylinders of red
earthenware, eight or nine inches in diameter. Those by which the smoke
of the fires is carried away, are cylinders of fire-brick clay, from
two to three inches thick, and from seven to ten inches in diameter.
In each fire-place, where the throat of the chimney is contracted over
the grate, there is a valve made of rolled iron plate, which fits into
a cast-iron seat fixed in the brick-work; when this valve is in its
seat, neither soot nor smoke can pass; and when it is thrown back, the
passage to the flue is unobstructed.
After describing the mortise locks for the doors, and the arrangements
of some French windows for opening into a balcony, both of which
exhibit ingenious and novel features, Loudon quotes a letter from
Hay, of Edinburgh, the author of a , and who superintended the interior decorations of the
house. The drawing-rooms are first spoken of thus:—The walls have been
prepared with several coats of white lead, grained to imitate morocco
leather; on this a pattern of gilded rosettes has been laid, and the
whole varnished with copal. Another pattern has then been superadded
in flat white, so that the whole has been compared in appearance
to a lace-dress over satin and spangles. Hay says: “There is
nothing very much out of my usual practice in the painting done in
Sir John Robison’s house in Randolph Crescent, except the walls of
the drawing-rooms and staircase. The bed-rooms were done in the usual
way; namely, ceilings sized on two coats of oil paint; walls papered
with a white embossed satin-ground paper, with small brown sprigs;
and the wood-work painted white, and finished with copal varnish.
The dining-room and[Pg 174] Sir John’s own room were both done in imitation
of wainscot, with white ceilings, varnished. The staircase ceilings
and cornices painted white and flatted; and the walls and wood-work
painted also white, and varnished with copal. The drawing-rooms and
ante-rooms were all painted white; the ceilings and cornices, as well
as the wood-work, being finished flat, and heightened with gilding.
The walls are, as I have already said, rather peculiar in their
style of painting. The ground work is rendered regularly uneven by
being granulated—by working it over with the point of a dry brush,
immediately applying the two last coats of paint. This is partly
varnished and partly flat, the flat parts forming large rosettes.
Between these rosettes are smaller ones, gilded, not in the base-metal
used upon paper-hangings, but in sterling gold leaf. This style of
decorative painting, from the great body of paint employed in producing
the granulated surface, the copal varnish, and the gold leaf, must
be of the most durable description. I may here mention, that during
the last two or three years, I have painted a very great number of
drawing-rooms in various styles, some with rich borders, others in
my patent imitation of damask, and a few in styles similar to that
employed upon Sir J. Robison’s; and have papered very few. I feel very
sure, that as the advantages of painting over papering, especially
in the public rooms of a mansion, become generally known, the latter
style of decoration will be entirely given up. As to the colouring
of ceilings, that must be left in a great measure to the taste of
the proprietor; as some like pure white, others delicate tints, and
a few go the length of the most intense colours, or polychrome. With
this last class I myself agree; but I am at the same time aware, that
if this be not done with the most strict attention to the laws of
harmonious colouring, the effect must be bad; it would be like a person
unacquainted with the science of music, running his fingers at random
over the keys of a powerful organ. In the one case, white, or a light
tint, is better than colours; and in the other, silence better than
such an attempt at music.”
A Beau-ideal English Villa.
The work from which the above has been derived, viz., Loudon’s
,
contains a chapter contributed by an anonymous writer, but devoted
to a singular and interesting subject. The object is to lay down
rules for the construction and furnishing of a villa which should be
the beau-ideal—the standard of excellence—of this class of
dwelling-house. He describes[Pg 175] the characteristics of the old English
country-house; and, taking that as his model, shows how modern
improvements may be brought to bear on the general arrangements of the
building. The description is too long to be given here in full, even
if it were right so to do; but we will condense into a few paragraphs
those details which relate to the construction and fittings of the
house, omitting all those matters which relate only to furniture.
The residence here described, or rather imagined, is the country house
of an English gentleman of ample means, but partaking much more of the
manorial than of the palatial character. The term villa
is not perhaps so fixed in meaning as to convey to every one the same
idea of the kind of building alluded to. The word was originally used
by the Romans to denote a farm-house, with the offices requisite for
the accommodation of a husbandman. Afterwards, when luxury increased,
the term villa was applied to the country residence of an
opulent Roman citizen. It is in a somewhat similar style that the word
is here to be used.
The villa being a place of agreeable retirement, but not one of
seclusion from the world, it should be situated within reach of a
public road, at an easy distance from the metropolis. “I should prefer
a situation removed about a mile from the great public road, and about
ninety miles or a day’s journey from the metropolis. Here I would
inclose a park of 100 or 150 acres; bounded on the north and west sides
by lofty wooded hills; on another side by a road; and elsewhere by the
inclosed country of the district; the surface of the park varied, but
gently inclining to the south, with a rapid stream of water passing
through it at no great distance from the site of the house.”
A villa (the writer proceeds to say) should always form part of a
village, and be placed if possible on rather higher ground. The old
English style of architecture is preferred; as being more picturesque
and ornamental; as according best with rural scenery; as, by admitting
great irregularity of form, it affords space for the various offices
and conveniences necessary in a country house; and as being better
suited to our climate than the Grecian style, which, by requiring
porticoes, projecting cornices, and windows of rather small size,
tends to intercept the light and make the house gloomy. The old style
also allows more variety of ornament upon the roof, such as the
stacks of chimneys, gables, pinnacles, turrets, and other appendages
to the general effect of a building when seen at a distance; whereas
in the Grecian style, which requires perfect symmetry of form, and
the prevalence of straight lines, these arrangements could not be
admissible.[Pg 176] For these reasons an old English or “Elizabethan” house
is selected. The front of the house would present a centre and two
projecting wings. The centre would contain the hall and dining-room,
with a gallery and staircase behind them. One wing would be occupied
by the drawing-room and library, with the saloon between them. The
other wing might contain a sitting-room, and superior offices for
servants; the inferior offices being on the basement, or in a separate
building in the kitchen-court. The principal part should be highly
ornamented, and form a symmetrical whole. In the centre would be the
porch of two stories, with its rich gable, small pillars, escutcheons,
&c.; the wall on either side (broken into compartments by pilasters,
or handsome buttresses, and proper string-courses) would contain large
mullioned windows; the whole supporting a battlement or parapet, with
its appropriate ornaments. The ends of the projecting windows would
present each a bay window of two stories, square or semicircular in
form, with balustrade or stone covering above; the gables of the wings
corresponding with that of the porch. The high and steep roof should be
varied by ornamental chimneys of different patterns, placed in their
proper situations; and, rising above them, the tower, containing the
grand staircase, appearing at a short distance behind the porch; its
waving cupola roof terminating in a rich lantern, and supporting a
weathercock or dwarf spire.
After giving his reasons for thinking that a country residence in the
Elizabethan style should have a kind of rich framework of courts and
gateways, balustraded terraces, and architectural gardens, the writer
proceeds to describe the interior of his supposed edifice, beginning
with the porch. This should be ascended by a flight of stone
steps; it should be floored with stone; and the ceiling, the door, and
the door-way, highly enriched.
The entrance-hall, which succeeds the porch, would vary in its
character according to the size of the house. In the large old English
mansions it was formerly the dining-room and place of rendezvous for
the servants and retainers; but in a smaller house, such as might be
termed a villa, and especially under the altered habits of English
society, a smaller hall, and one more nearly resembling a mere
entrance, would be fitting. An English hall admits of much picturesque
embellishment, such as a carved oak roof or ceiling, either flat or
semicircular, enriched with highly-wrought bosses or coats of arms; a
music gallery across the end, supported by pillars or a carved screen;
a chimney-piece reaching to the cornice of the roof; and a carved
wainscot covering half the height of the walls.
Having entered the porch-door, and crossed the lower end[Pg 177] of the hall,
entrance would be gained to the gallery, a sort of an in-door
promenade, between the hall and the staircase; having one door leading
to the saloon, another to the billiard-room, and another to the
domestic offices. “The staircase is an important convenience in every
house; and it should always be a striking feature in a mansion of any
elegance. The tower, which I suppose to contain the staircase, would
be square, as high as the ceiling of the upper floor, where it would
take a sort of octagon form; the roof coned, and ending in a lantern:
in the centre of the lantern a boss would support a lamp. In the side,
opposite to the arch by which you enter, would be a tall mullioned
window filled with stained glass. Advancing a few steps, you would
reach the first flight in the middle of the tower, and ascend to the
first landing-place; you would find a flight of stairs on the right
and left leading to the second landing, in the centre of which is the
upper gallery door, immediately over the arch below. As the house is
to be in the old English style, the stairs might be either of oak or
stone; but the balusters must be of oak handsomely carved, and rather
heavy. They might begin at the foot of the stairs with a richly-carved
sort of pedestal, and the same at each corner as they ascend. In old
staircases there was frequently an animal of some sort sculptured in
wood, supporting the family arms, placed on these pedestals, especially
at the foot of the stairs; or the animal had a substitute in a ball or
pine-apple.”
The chief apartments on the ground floor are described as being the
saloon, the drawing-room, the library, the dining-room, and the study.
The saloon is generally a sort of vestibule to the dining-rooms; and,
supposing it to be such in this case, and of a parallelogram form, its
arrangement is thus sketched:—The entrance door is in the centre of
the side next the gallery; in the centre of the end on the right hand
would be the drawing-room door, and in the centre of the other end the
library door. On the other side should be two windows, with a glass
door between them opening to the terrace and garden. The drawing-room
would be larger than the saloon. On entering from the saloon the
opposite end would present a square or circular bay-window, commanding
a view of the park and the distant country beyond it. On the right side
would be the fire-place, and on the opposite side two windows looking
over the terrace.
Crossing the saloon from the drawing-room we should arrive at the
library. This would be about the same size as the drawing-room, and
would, like it, have a bay window opposite the entrance, and two other
windows opposite the fire-place. This room, it is supposed, would be
the family[Pg 178] sitting-room when there is no company in the house; and
would be the forenoon resort of the gentlemen when guests are stopping
at the house; and hence arises a very minute and curious detail of the
manner in which the library should be fitted up, in order to answer
this double purpose. These, however, we cannot enter upon; but the
following will give an idea of the manner in which this imaginative
house-builder fills up the rooms of his villa:—“As to the smaller
ornaments to be placed around the room, they should be curious and
interesting, and on no account frivolous. Handsome silver inkstands, a
few curious fossils, or models of celebrated buildings; all sorts of
writing-cases and implements, taper stands of silver, boxes of coins,
old china in large jars, and anything of these kinds, with handsome
books, might decorate the tables; and, as nothing gives a room a more
dismal effect than an appearance of idleness, everything should be so
arranged, both here and in the drawing-room, as if the persons using
the rooms had been employed in some way or other. This effect would
be produced by the daily papers, and some periodical works, and open
letters received in the morning, on the principal tables; and, on other
tables, some of the blotting-books might be open; the inkstands not
thoroughly in order, with some unfinished writing and open books or
portfolios, would give at least the appearance of industry. I do not
recommend such foolish tricks, which are, I know, often used by idle
people, who have sense enough to feel the bad taste of indolence; and
in a sensible family, who spent their time rationally, this would be,
in fact, the usual state of the room, at least during the morning.”
The dining-room of the beau-ideal villa is contiguous to the
hall, whence entrance is obtained by double doors. The walls are
covered with old oak wainscot. The fire-place should be very large,
reaching nearly to the ceiling, and all the fittings and arrangements
of a massive, solid, and handsome kind. The gentleman’s study, or
business room, would be a smaller, plainer, and more strictly private
room, on the same floor, and used for writing, reading, and transacting
business.
Having disposed of the principal apartments, the writer proceeds
to describe the rooms on the next floor above, occupied chiefly as
bed-rooms. The grand staircase leads up to a second gallery, over
the lower one; and in this gallery are the doors of all the best
sleeping-rooms. The sitting and sleeping nurseries are also on this
floor; as is likewise the governess’s sitting-room, “in a quiet part
of the house.” The bed-rooms for the servants are on the upper floor,
approached by the back staircase.
[Pg 179]
Then we descend to the basement of the house, where the various
servants’ rooms are situated. The housekeeper’s room should be a
spacious comfortable room, furnished as a respectable parlour; and so
situated that the other offices may be overlooked by the housekeeper. A
door in this room should open into the still-room, which is the common
sitting-room of the under female servants, and where portions of the
ordinary operations are carried on. A store-closet opens conveniently
into the still-room, and has conveniences for arranging the stores
and provisions as they are unpacked. The butler’s pantry, being the
room in which the plate is lodged, should be placed in a part secluded
from the back entrance to the house, and should have strong doors and
window-shutters to prevent depredation. The servants’ hall would be
near the back entrance to the house, and easy of access. Here all the
under servants would dine, and it would be the common sitting-room
for the males. The larders, if the house were large, would be four in
number; the wet larder for undressed meat, the dry larder for cold
meat, the game larder, and the pastry.
The kitchen, as being one of the most important rooms in a hospitable
mansion, is treated with due importance. The writer describes the
arrangements in the kitchen of a mansion in Warwickshire, as being
fitted to serve as a model. “The kitchen, scullery, larder, &c., formed
a range of building on one side of the kitchen-court, separate from
the house, but there was a covered way between them. The building was
of two stories, the kitchen occupying the centre. It was a large lofty
room, of good proportions, as high as two stories of the building. You
entered it at one end, by large folding-doors, from a passage through
the building; at the opposite end was the fire-place, with the screen
before it; on one side of which was the door to the scullery and
bakehouse, on the other a range of set coppers of different sizes. On
one side of the room were two rows of windows, and under the lower row
a range of charcoal stoves and hot plates: the latter to keep things
warm. The other side had only the upper row of windows, and against the
wall was a dresser, above which the copper cooking utensils, &c., were
ranged in a very ornamental way. A long table was in the centre of the
room, and over the door a dial-clock. The ceiling had a very handsome
cornice, and a boss in the centre, from which hung a brass lamp.
Opposite the entrance door another door admitted you to a passage, on
one side of which were the larders, on the other salting-rooms, &c.;
and at the end a staircase led to the cook’s apartment over. There
was a sort of turret in the[Pg 180] centre of the roof, containing a capital
clock, which struck upon the dinner bell. The other offices were in
the basement of the house, and the kitchen was detached, to prevent
the annoyance of the smell of cooking, which commonly ascends from
a kitchen beneath the house. I thought the arrangement particularly
convenient, and the kitchen was really an elegant apartment. As, in a
large establishment, there is cooking going on through the whole day,
it is of importance to the comfort of the family, to place the kitchen
in such a situation that the smell of cooking, which is particularly
offensive, may not be an annoyance to the principal apartments. A house
with the kitchen in the basement story is generally subject to this
inconvenience, and it is usually avoided by having the kitchen and
offices in a separate building adjoining the house.”
The writer continues his remarks and descriptions in a similar manner,
treating of all the various parts of the building in succession; then
of the riding-house, the stable-yard, the coach-houses, the harness
and saddle rooms, and the dog-kennel; then of the kitchen garden,
the pleasure garden, the dairy, the farm buildings for a “gentleman
farmer;” and, lastly, of the village and the village church, so far
as regards the relation between them and the mansion. In short, this
writer seems to have proposed to himself this question—“What are the
excellencies to be desired and attained in the mansion of an English
country gentleman?” and he appears to have solved it by putting
together the scattered fragments of his experience in various quarters,
and building up an ideal mansion therefrom.
[Pg 181]
CHAPTER XII.
FIRE-PROOF HOUSES.
The attempts which have been made to render houses fire-proof are so
intimately connected with the construction of dwellings, that it will
be proper to give a few brief details on the subject. There are many
difficulties attending these attempts; for so long as wood forms the
chief inner frame-work of a house, there will always be considerable
liability to destruction by fire. Most of the proposed plans have had
relation to the coating of the wood with some substance which should
render it less inflammable, while others have been directed rather to
the rejection of combustible substances from the list of those used in
house-building.
So long back as 1775, Hartley made several trials in order to
test the efficacy of a method invented by him for that purpose. Thin
iron plates were nailed to the top of the joists; the edges of the
sides and ends being lapped over, folded close, and hammered together.
Partitions, stairs, and floors were proposed to be defended in the same
manner. The plates were so thin as not to prevent the floor from being
nailed on the joists in the same manner as if the iron were not used;
and the plates were kept from rust by being painted or varnished with
oil and turpentine. Hartley had a patent for this invention; and
Parliament voted a sum of money towards defraying the expense of his
numerous experiments. It does not, however, appear that the plan was
permanently adopted.
About the same period, Lord Mahon, afterwards Earl Stanhope, a nobleman
possessing a highly inventive tact in mechanical matters, brought
forward another method having the same object in view. This method
was of a three-fold character, comprising under-flooring,
extra-lathing, and inter-securing.
The method of under-flooring is either single or double. In single
under-flooring, a common strong lath of oak or fir, about one-fourth
of an inch thick, should be nailed against each side of every joist,
and of every main timber, supporting the floor which is to be secured.
Other similar laths are then to be nailed along the whole length of the
joists, with their ends butting against each other. The top of each of
these laths or fillets ought to be at an inch and a half below the top
of the joists or timbers against which they are nailed; and they will
thus form a sort of small ledge on each side of all the joists. These
fillets are to be well bedded in a rough[Pg 182] plaster when they are nailed
on, so that there may be no interval between them and the joists; and
the same plaster ought to be spread with a trowel upon the tops of
all the fillets, and along the sides of that part of the joists which
is between the top of the fillets and the upper edge of the joints.
In order to fill up the intervals between the joists that support the
floor, short pieces of common laths, whose length is equal to the width
of these intervals, should be laid in the contrary direction to the
joists, and close together in a row, so as to touch one another; their
ends must rest upon the fillets, and they ought to be well bedded in
the rough plaster, but are not to be fastened with nails. They must
then be covered with one thick coat of the rough plaster, which is to
be spread over them to the level of the tops of the joists; and, in a
day or two this plaster should be trowelled over, close to the sides of
the joists, without covering the tops of the joists with it.
In the method of double-flooring, the fillets and short pieces of laths
are applied in the same manner as here noticed; but the coat of rough
plaster ought to be little more than half as thick as that in the
former method. Whilst the rough plaster is being laid on, some more of
the short pieces of laths must be laid in the intervals between the
joists upon the first coat, and be dipped deep in it. They should be
laid as close as possible to each other, and in the same direction with
the first layer of short laths. Over this second layer of short laths
there must be spread another coat of rough plaster, which should be
trowelled level with the tops of the joists, without rising above them.
The rough plaster may be made of coarse lime and hair; or, instead of
hair, hay chopped to about three inches in length may be substituted
with advantage. One measure of common rough sand, two measures of
slaked lime, and three measures of chopped hay, will form in general
a very good proportion, when sufficiently beaten up together in the
manner of common mortar. The hay should be put in after the two other
ingredients are well mixed up together with water. This plaster should
be made stiff; and when the flooring boards are required to be laid
down very soon, a fourth or fifth part of quicklime in powder, formed
by dropping a small quantity of water on the limestone shortly before
it is used, and well mixed with this rough plaster, will cause it to
dry quickly. If any cracks appear in the rough plaster work near the
joists, when it is thoroughly dry, they ought to be closed by washing
them over with a brush wet with mortar wash: this wash may be prepared
by putting two measures of quicklime and one of common sand into a
vessel, and stirring the[Pg 183] mixture with water till the water becomes of
the consistence of a thin jelly.
Before the flooring boards are laid, a small quantity of very dry
common sand should be strewed over the plaster work, and struck smooth
with a hollow rule moved in the direction of the joists, so that it
may lie rounding between each pair of joists. The plaster work and
sand should be perfectly dry, before the boards are laid, for fear of
the dry rot. The method of under-flooring may be applied to a wooden
staircase, but no sand is to be laid upon the rough plaster work. The
method of extra-lathing maybe applied to ceiling joists, to sloping
roofs, and to wooden partitions. The third method, which is that of
inter-securing, is very similar to that of under-flooring; but no sand
is afterwards to be laid on. Inter-securing is applicable to the parts
of a building as the method of extra-lathing.
Such is a general outline of the modes proposed by Lord Mahon for
rendering houses fire-proof; in which it will be seen that the
safeguard consists in the use of a non-combustible material, with, and
among, and between the pieces of wood forming the frame-work of a house.
The more recent attempts to gain the same object by means somewhat
similar have been very numerous; some of which we may here notice as
examples of the whole.
An American patent was granted in 1837 to a Louis Pambœuf, for
the invention of a fire-proof paint. The mode of preparing it is thus
described. A quantity of the best quicklime is selected, and slacked
with water in a covered vessel; when the slacking is complete, water,
or skimmed milk, or a mixture of both, is added to the lime, and
mixed up with it to the consistence of cream. When milk is not used a
solution of rice paste is employed, obtained by boiling eight pounds
of rice to every hundred gallons of paint. When the creamy liquor is
prepared, alum, potash, and common salt are added, in the proportion of
twenty pounds of alum, fifteen pounds of potash, and a bushel of salt,
to every hundred gallons of the paint. If the paint is to be white, six
pounds of prepared plaster of Paris and the same quantity of fine white
clay are added to the above proportions of the other ingredients. All
these ingredients being mingled, the mixture is strained through a fine
sieve, and then ground in a colour-mill.
When roofs are to be covered, or when crumbling brick walls are to be
coated, fine white sand is mixed with the paint, in the proportion of
one pound to ten gallons of paint; this addition being made with a view
to giving the ingredients a binding or petrifying quality. In applying
this paint,[Pg 184] except in very warm weather, it is prepared in a hot
state; and in very cold weather precautions are necessary to prevent
it from freezing. Three coats of this paint are deemed in most cases
sufficient.
In another variety of this paint oil is the chief liquid ingredient. To
prepare it forty gallons of boiled linseed oil are mixed with slacked
lime to the consistence of a paint; and to this are added two pounds
of alum, one pound of potash, and eight pounds of common salt; or good
wood-ashes may be substituted for the potash. This paint is used in the
same manner as other paint; and any colour may be obtained by adding
the usual pigments to the composition.
The preparation of a kind of paint containing alkalies seems to have
been a favourite measure among inventors of “fire-proof” composition;
for many of the modern projects have had this for its basis. But in
most cases there have not been means for determining the degree of
efficacy possessed by these compositions. There were, however, a few
years ago trials made of rather an interesting character, which were
described in the public journals, and which were of the following
nature.
In 1838, a company was formed for the sale and use of a composition
of this kind, and an experiment was made in the Clapham Road to show
its efficacy. The house, which was a small one, had been built in the
usual way, with the intention of being fitted up in the ordinary style.
While yet a mere shell, all the boards, timbers, floors, ceilings,
stairs, and wood-work generally, were coated thickly with a greyish or
slate-coloured composition, which dried to a state of great hardness.
On a particular day the upper floor was covered with shavings in great
abundance, to which a number of deal planks were subsequently added.
The first floor front room was fitted up as a chamber, with bed and
furniture, chairs, tables, &c., as nearly as possible in the usual
style. The shavings and wood on the upper floor were then kindled, as
were also planks and shavings placed on the floor of the furnished
room. The consequence of this was that the two rooms speedily exhibited
a blaze of light: the whole of the furniture (purposely selected of an
inexpensive kind) being ignited. The flames burst from the windows; but
although the entire contents of the room were consumed, the fire did
not communicate to the floor above, nor to that beneath, nor even to
the other room on the same floor. Several small parcels of gunpowder
were introduced between the ceiling of the burning room and the floor
of the room above it; but[Pg 185] they did not ignite; nor were the other
parts of the house injured in any material degree.
Another trial took place at the White Conduit Gardens; where two close
wooden buildings, of the size and shape of sentry boxes, were placed in
the grounds. One of them was coated on the inside to the thickness of
about an eighth of an inch with the composition, and was also partially
covered on the outside; while the other was left in the plain wood
state. A flooring was placed at about the centre of each of these, and
through the holes in front shavings were put and then ignited. The box
which was not coated with the composition was soon in flames; while
the fire in the other went out without having had any effect upon the
general structure. The building which was in flames was then placed
contiguous to the partially-coated outside of the other, and although
it was not materially injured, the exterior coating peeled off in some
places, and the wood became charred; the interior, however, appeared
perfectly uninjured by the flame.
If the results of these experiments were really such as the description
would seem to imply, it might excite surprise how it happens that no
practical results have followed. But there are always numerous reasons
why an experiment, which succeeds under circumstances made for
the occasion, should not be available in practice; and it is probable
that some such discordance may exist here. Perhaps the mode in which we
may more consistently look for the practical attainment of the object
in view is by the adoption of some improved mode of building, in which
either wood is not employed at all, or, where sparingly used, measures
are taken to shield it from the action of fire. One such method is
Leconte’s, described as follows.
This plan consists in the employment of iron frames to receive concrete
matter for forming the walls. The basement story of the building is
constructed according to the ordinary methods up to one foot or more
above the ground. On the basement so constructed is to be erected the
patent wall, formed of frames entirely of cast-iron, in one or more
pieces, or a combination of cast-iron and wrought-iron plates. These
frames are to be set one on the other until the required height is
attained, the necessary stability being obtained by means of steady
pins at the corners of one frame fitting into holes made in the
corners of the frame which is opposed to it. Suitably-shaped frames
are employed for the internal partition walls, and for doorways,
window-frames, &c. The flues of the chimneys are formed of iron or
other metal pipes, placed in the thickness of the walls. When the
required elevation is obtained, a concrete of any suitable material is[Pg 186]
poured into the framing, and fills up the vacant space, giving firmness
and solidity to the structure; the concrete being made of gravel and
lime. To give steadiness, lead is to be introduced between the joinings
of the iron-work. The doors and window-frames are to be fastened to
the walls by any of the usual known methods. The main beams and cross
beams of floors and roofs may be of cast-iron, or formed of iron and
wood; or they maybe formed of one or more pieces of plate-iron, bent up
into an oval form, and straightened by an iron or wooden bar passing
through them lengthwise, the upper edges of the metal being turned
over to increase the strength. In the interval between the beams there
are to be iron rods running in various directions, and supporting a
metallic wire-work, which forms the foundation for the ceiling. Similar
wire-work is to be employed in lieu of laths for plaster surfaces. All
the iron-work is to be painted over with some suitable composition to
prevent oxidation.
A plan for the same purpose has been proposed by Varden as
follows:—“It appears probable that common fir or oak joists with
their lower edges chamfered, and coated over with a mixture of alum,
black lead, clay, and lime, or some similar composition, would (if
closely floored above with earthenware tiles, bedded all round into
the plastering, the joists being made air-tight) resist the action
of flames, at least for a considerable time. Fire could not descend
through such a flooring so as to communicate with the rooms below, till
the tiles used in it had become red-hot; neither could it ascend until
the tiled floor above gave way, from the burning of the joists; which,
if coated as proposed, would not take fire from below till the tiling
over them acquired a sufficient heat to cause the distillation of the
turpentine from the wood. In general, there is not furniture enough of
a combustible nature in any room to do this. The battening against the
outer walls might be of larch, as that wood burns less freely than most
others; but if the walls were brick, or lined with brick, battening of
any kind will be unnecessary. If this plan should be thought likely to
answer the end proposed, houses built in the common manner might be
altered at a moderate expense, by taking up the boarded floors, and
substituting earthenware tiles.”
Another Plan, proposed by Frost, consists in forming the floors of
rooms of hollow earthenware tubes embedded in cement, combined so as to
form a sort of flag-stone, covering the whole floor. These hollow tubes
are square in section, about an inch and a half on the side externally,
with a tubular space of an inch and a quarter on the side internally;
they are formed of brick earth, prepared in a superior manner,[Pg 187] and
pressed through moulds by machinery; and their length is about two
feet. In forming a floor of these tubes, the centering, after being
prepared and fixed in the usual manner, is first covered with a coating
of cement of a quality sufficiently fine to form the ceiling of the
apartment to be floored over; and if it is desired that there should
be mouldings or ornaments in this ceiling or its cornices, moulds for
them can be placed in the centering, so as to form a part of it. One
or two coats of cement having I then been laid over the centering, a
stratum of the square tubes laid side by side, and breaking joint,
is next embedded in fine cement, and the interstices between them
also filled in with that material. One thin coating of cement is then
laid over the whole stratum; and in a week, when this is dry, another
stratum of tubes is laid over the first in a contrary direction, bedded
and filled in with cement as before, and finished by a coating of the
same material. This, when dry, may have a second coating to serve as
the floor of an upper apartment, or the covering of a roof, as the case
might be.
Loudon gives descriptions of two methods, the one for building
houses in general fire-proof, and the other for imparting that
property to houses already built. He considers the two main points
for consideration to be, to have staircases of iron or stone, or both
combined, and to avoid having any hollow partitions or floors. A house
having a stone or iron staircase, and having all the partitions either
of four-inch brick-work, or of brick nogging, in whatever way it might
be set on fire, could hardly be burned down, if ordinary exertions were
made to extinguish the flames. One apartment might be set on fire, but
before the flames could spread to the one under or over it, or to a
staircase adjoining it, the fire might be extinguished. In a house so
constructed, there would be no piece of timber that was not in close
contact with mortar, at least on one side; and all the strong pieces
of timber, such as joists, rafters, quartering in partitions, &c.,
would be closely embedded in mortar on two sides. Where the partition
could not be made entirely of brick, the interstices might be filled
up with a mortar prepared of clay with a small proportion of lime. The
same material might be filled in between the joists, and where it was
desired to render the roof fire-proof, the rafters might be made of
iron, or the space between wooden rafters might be filled in with thin
mortar. This mode of proceeding would lengthen the time required for
the drying of a newly-built house, and would also add somewhat to the
expense; but it is conceived that the increased safety would more than
counterbalance these inconveniences.
[Pg 188]
In respect to the means of giving a fire-proof quality to a house
already built, Loudon remarks:—“All the interstices between the
floors, in the partitions, and in the roof, where there was a ceiling
formed to the rafters, might perhaps be filled in with earthy matter
in a state of powder. This powder might be clay or loam mixed with
a small proportion of Roman cement; it might be injected into the
vacuities, through small orifices, by some description of forcing-pump
or bellows, which, while it forced in the powder, would permit the
escape of the air; and, while this operation was going forward steam
might be injected at the same time, so as to mix with the mortar and be
condensed by it; by which means the whole mass would be solidified with
a minimum of moisture. In short, in rendering houses fire-proof, the
next important object to using fire-proof materials, is that of having
all the walls and partitions, and even the steps of wooden staircases,
filled in-with such materials as will render them in effect solid. On
examining into the causes of the rapidity of the spread of the flames
in London houses when on fire, it will almost invariably be found,
that whatever may have occasioned the fire to break out, the rapidity
of its progress has been in proportion to the greater or less extent
of the lath and plaster partitions, the hollow wooden floors, and the
wooden staircases. Were the occupiers of houses sufficiently aware of
the danger from lath and plaster partitions, especially when inclosing
staircases, they would never occupy such houses, or, if they did, they
would not give such rents for them, as they would for houses with
brick-nogging partitions. It appears to us to be the duty either of the
general or local government or police to see that no houses whatever
are built without stone or iron staircases; and that no partitions and
floors are made hollow; or, if they are, that the materials should
be iron and tiles, or slates, or stones, or cement, or other earthy
composition.”
[Pg 189]
Chapter XIII.
MISCELLANEOUS PROCESSES.
The various processes and details which have occupied the preceding
chapters, are for the most part necessary to the production of every
house. There are, however, many articles of iron and a few of brass
employed in the interior and exterior fittings; but were we to enter
into details respecting the iron manufacture, in order to show the
modes of producing these articles, it would be difficult to confine
this volume within reasonable limits. A few miscellaneous processes and
details may, however, be collected in this chapter.
The principal metallic articles employed in the construction or
permanent fittings of a house, are nails and screws; hinges; locks and
keys; stoves and grates; bells, and the mechanism for hanging them;
iron railings and bars; brass handles, plates, and other decorations;
latches and fastenings, &c.
Nails.
Nails are made of iron, either cut by means of a machine into the tapering form which we call cut brads, or wrought by means of hammers into the various forms of flooring nails, tacks, &c. Screws are made by forcing a piece of iron wire into a cavity, the surface of which is cut into a spiral or screw-like form; this spiral cuts a similar spiral on the surface of the iron wire, which then becomes a screw; and one end of the wire is hammered or pressed down so as to form the head of the screw. Hinges of the commoner kinds are made by two flat pieces of iron, with a kind of projecting tube at one edge. These tubes are partially cut away, so that the two pieces may lap into each other; and a spindle or pin being passed down through both tubes, acts as an axis, on which both parts of the hinges turn. The more costly hinges require elaborate workmanship in their construction.
Locks and Keys.
Locks and Keys form a curious part of the hardware manufacture. The lock is made of a great many pieces, put together with screws. One part of it is always a moveable latch or bolt, which is capable, by tolerable force, of being thrust partially out through a hole in the side of the lock; and it is this bolt which, catching in a box or cell fixed to the door-post, secures the door to which the lock is attached.[Pg 190] The object of the key is to act as a lever which shall move the bolt; and the great point of attention in the matter is, that no key or lever but one of a particular size and shape shall be able to move the bolt; herein is the security which we feel in a good lock. Wolverhampton and its neighbourhood is the great seat of the lock manufacture.
Stoves and Grates.
Stoves and Grates are made in a variety of forms. Their employment is obviously greatly dependent on the kind of fuel employed. In the kitchens of the old baronial residences, large logs of wood were thrown upon an immense stone or brick hearth, and there kindled. But when coals became commonly used in London and other great towns of England, about the year 1400, the use of some kind of stove or grate began to be felt, since the fuel was too valuable to be scattered on a wide-spreading hearth. From that time to the present, one continual series of improvements has taken place, having for their objects, to add to the elegance and neatness of a room, to facilitate culinary occupations, and to derive the greatest possible heat from a given quantity of fuel. It is only within a very few years that the principles regulating the last-mentioned circumstance have been at all well understood. Some parts of the metal for a grate or stove are produced by casting, others by forging, and others by rolling or pressing; and they are put together principally by rivets. For further details on this subject we refer to our seventh chapter.
Bells.
Bells are, generally speaking, made of an alloy of copper and
tin, which possesses more resonant qualities than most others. There is
also a little ball or clapper suspended in the bell, which, by striking
against it, produces the same effect as the hammer which strikes the
outside of a church bell. The bell is generally fixed in a different
part of the house from the handle with which it is rung, and the
connexion between them is made by means of copper wire. As the wire
has to turn round many corners and angles, it is fixed, at each corner
to a crank, which is a kind of hinge or lever, so contrived as
to transfer motion in a new direction at right angles to the former.
Considerable care is required on the part of the bell-hanger, to
prevent the wire from becoming entangled or interrupted in its free
communication from the handle to the bell.
[Pg 191]
Brass Handles, Ornaments, &c.
Those are produced by turning, by casting, by
stamping, or by drawing. In the first mode, the article
is placed in a lathe, and turned by tools made of hard steel: in the
second mode, melted brass is poured into moulds formed generally of
sand, by which any desired form is produced: in the third mode, two
stamps, one called a matrass and the other a die, are
cut or moulded to similar figures; a piece of sheet brass is laid on
the matrass or lower stamp, the die or upper stamp is laid on the
brass, and a powerful blow, either from a hammer, or from machinery,
forces the brass to assume the form given to the two stamps. By the
last mode, a slip of thin brass is forcibly drawn between two rollers,
whose surfaces are indented with the requisite device, which device is
thereby impressed on the bars. In one or other of these ways, most of
the brass-work in our houses is made.
Iron railings and bars of various kinds are made either
by forging or casting, and do not call for further notice here.
Preservation of Timber.
In our notices of the timber which enters into the construction of a
house, no mention was made of the existing methods of preparing it so
as to resist the action of dry rot and other decomposing agencies.
Timber so prepared is not in very general use in house-building, and
hence the notice of it occupies a more fitting place in the present
chapter.
Vegetable matter, in common with all organic substances, is subject
to decomposition and decay, as soon as life becomes extinct; and
although the process is comparatively slower in its commencement
and progress in vegetable than in animal matter, it is not, under
ordinary circumstances, the less certain. During the existence of
a plant, its various organs, under the influence of the mysterious
principle of life, perform their respective functions in a manner
similar to that of which we are more readily conscious in the animal
frame. The plant absorbs its food from the soil and the surrounding
air; it digests that food under the influence of respiration, and
prepares rich and nutritive juices which circulate throughout its whole
vegetable frame, and deposit materials of growth wherever they are
wanted; it sheds its leaves in autumn, undergoes a season of torpor,
and again becomes active and vigorous; thus it is clad in fresh leafy
honours in the following spring. All this is the effect, or rather the
result, of vitality. The plant dies, and then its constituent[Pg 192] parts
gradually assert their individual existence, and resume their original
affinities. Some pass into the air; some form new compounds; and
others, which during the life of the plant ministered to its healthy
action, now work energetically and destructively on each other; so
that the original mass gradually decomposes under the influence of
various causes. The first step to decay is a process of fermentation,
which is more or less rapid in proportion as heat and moisture are
more or less present. In the absence of damp air, even the vegetable
mass will of itself supply moisture; for, according to Count Rumford,
the best-seasoned timber retains one-fourth of its weight of water. A
certain extent of moisture is essential to vegetable fermentation; but
a complete saturation appears inimical to it. A temperature not so low
as to produce freezing, nor so high as to produce rapid evaporation, is
also favourable to it. The humidity of the air in ships, and in houses
built on clay or in moist situations, and the difficulty of obtaining
a free circulation of air, contribute greatly to this fermentative
process.
The chemical constitution of the vegetable kingdom yields to analysis
only three or four ultimate elements, viz., oxygen, hydrogen, and
carbon, and sometimes nitrogen. The most active agent in the process
of decomposition is the oxygen contained in the dead plant, whether
such decomposition proceed under the rapid influence of fermentation,
or be produced more slowly by the operation of the law which renders
decay the necessary consequence of organization. As soon as the tree
is felled, the oxygen begins to be liberated and to act upon the woody
fibre, combining with its carbon, and producing carbonic acid gas. The
tenacity of the several parts is thus gradually destroyed. After timber
is felled, and during the process of seasoning, a gradual diminution
of strength may be remarked. The effect, however, of seasoning is to
deprive the wood of superabundant moisture, and of those vegetable
juices which would otherwise induce a rapid decomposition.
In addition to the natural decay of timber, the decomposition is often
accompanied by the apparently spontaneous vegetation of parasitical
fungi, inducing a species of decay to which the term “dry rot” is
applied, probably in consequence of the attendant phenomena; the wood
being converted into a dry friable mass, destitute of fibrous
tenacity. It is uncertain whether the seeds of these fungi exist in
a dormant state in the juices of the timber, and wait only until the
first stages of decomposition furnish them with a nidus favourable to
their growth; or whether they float in the atmosphere and settle in
places favourable to their vegetation. It is found,[Pg 193] however, that
badly-seasoned timber is peculiarly subject to this species of decay;
and hereby the former of the two suppositions is favoured.
From the moment when timber is felled, the process of decay commences,
and although so slowly in many cases that we are not conscious of it,
yet there is a limit to the existence of the most durable articles
of wood, however carefully preserved. Dryness, cleanliness, a free
circulation of air, or the entire exclusion of it, are among the best
checks to vegetable decomposition: while damp accumulations, and a
vitiated atmosphere, rapidly induce it.
Unseasoned timber should never be used in carpentry, and the
best-seasoned timber should be used only in a dry state. Diseased and
decayed portions of the wood should be cut out, together with the
sap-wood, which, being more soft and porous than the spine, is more
liable to fermentation.
The iron fastenings used about timber frequently cause its premature
decay. Iron, under the influence of moisture becomes rusty, that is,
oxygen, either from the air or from the wood itself, unites with the
metal, forming an oxide, which, in its turn acts upon the woody fibre,
and gradually destroys its tenacity. The iron is further subject to
attack from the acid juices of the wood; this effect, however, varies
in different woods. Oak contains a smaller proportion of oily or
resinous particles than many other kinds of wood; and, in addition
to the usual vegetable acid common to most woods, oak contains an
acid peculiar to itself, called gallic acid. In teak, on the
contrary, the quantity of acid is not only smaller, but the resinous
particles are very abundant, and these form a sort of protecting
covering to the iron fastenings. Maconochie states, on the authority
of the shipping built in India and used in the India trade, that the
average duration of an iron-fastened teak ship is thirty years; and
that it is a misapplication of expense to use copper fastenings with
teak, as the additional advantage gained is not at all commensurate
with the additional expense. But it is different with oak; the action
of oak on copper is by no means so destructive as on iron, and the
reaction of the metal on the wood is not so destructive.
The methods which have been from time to time adopted for the
preservation of timber are so numerous, that a slight sketch of them
would probably fill a good-sized volume. We will name a few of the most
successful, and terminate this notice with a description of the method
now in practice.
Maconochie recommends all the iron fastenings to be provided with
a protecting paint, and to impregnate the timber with some oily
preparation, which he proposes to effect thus:[Pg 194] the wood is to be
placed in a steam-tight chamber, and subjected to the action of steam,
by which the air will be expelled from the timber. Then by condensing
the steam, and repeating the process until all the elastic fluids are
withdrawn from the wood, and its juices converted into vapour, the
wood becomes freed from them, and if plunged into oil, and subjected
to atmospheric pressure, all the internal cavities of the wood will
be filled with oil. In this way, Maconochie had in daily use a
steam-chamber capable of containing twenty or thirty planks of timber
forty feet long, in which, while the planks were steaming, to render
them flexible, they were impregnated with teak oil. He says the oil may
easily be procured from the chips and saw-dust used for the fuel of the
steam-boilers; for it has been ascertained that Malabar teak contains
such a quantity of oleaginous (oily) or terebinthinous (turpentine)
matter, that the chips from the timber and planks of a ship built of
it will yield, by a proper process, a sufficient quantity of tar for
all its own purposes, including the rigging; and that, although oak
timber does not contain so much of these substances, the chips of the
fir alone consumed in the Royal Navy, would be more than sufficient to
supply tar to saturate the oak.
There have been many other proposals to saturate timber with different
substances; the most successful of which, up to the process of
Kyan, was that of M. Pallas, whose plan was to saturate the timber in
a solution of sulphate of iron, and then precipitate the salt by means
of lime-water. About the year 1822, Bill produced samples of timber
impregnated throughout with a substance resembling asphaltum. These
samples were subjected to a trial of five years in the dry-rot pit
at Woolwich, and withstood the fungus-rot perfectly. Sir John Barrow
recommends kreosote, which he says, “in a vaporous form, penetrates
every part of the largest logs, and renders the wood almost as hard as
iron—so hard as not easily to be worked.”
Kyan’s plan, now so universally adopted, is to soak the timber in a
solution of bichloride of mercury, commonly called corrosive sublimate.
“Aware of the established affinity of corrosive sublimate for albumen,
Kyan applied that substance to solutions of vegetable matter,
both acetous and saccharine, on which he was then operating, and in
which albumen was a constituent, with a view to preserve them in a
quiescent and incorruptible state; and obtaining a confirmation of
his opinions by the fact, that during a period of three years, the
acetous solution, openly exposed to atmospheric air, had not become
putrid, nor had the saccharine decoction yielded to the vinous
or[Pg 195] acetous stages of fermentation, but were in a high state of
preservation, he concluded that corrosive sublimate, by combination
with albumen, was a protection against the natural changes of
vegetable matter. He conceived, therefore, if albumen made a part of
wood, the latter would be protected by converting that albumen into
a compound of protochloride of mercury and albumen; and he proceeded
to immerse pieces of wood in this solution, and obtained the same
result as that which he had ascertained with regard to the vegetable
decoctions.”—Birkbeck.
It having been found that the precipitate caused by the Kyanization
was soluble in salt water, Sir William Burnett has lately substituted
chloride of zinc for corrosive sublimate, and the resulting compound
which this forms with the albuminous portion of the wood, effectually
resists the action of salt water.
Soluble Glass.
A remarkable method of preserving wood-work, and rendering it
fire-proof, was invented some years ago by M. Fuchs, in consequence of
his discovery of a kind of glass which could be prepared and kept in a
liquid state, and hardened only on being exposed in a thin layer to the
air.
Soluble glass is a union of silica and an alkali, which has, in
addition to some of the properties of common glass, the property of
dissolving in boiling water. The preparation of soluble glass does
not greatly differ in its early stages from that of common glass, an
account of the manufacture of which will be found in the eighth chapter.
When sand and carbonate of potash are heated together, the carbonic
acid is not entirely driven off, unless the sand be in excess, but the
whole of the gas may be expelled by the addition of powdered charcoal
to the mixture.
Carbonate of potash and pure sand being taken in the proportion of
two to three, four parts of charcoal are added to every ten parts of
potash and fifteen of sand. The charcoal accelerates the fusion of the
glass, and separates from it all the carbonic acid, a small quantity of
which would otherwise remain, and exert an injurious effect. In other
respects the same precautions that are employed in the manufacture
of common glass are to be observed. The materials must first be well
mixed, then fritted, and finally melted at a high heat, until a liquid
and homogeneous mass be obtained. This is removed by means of an iron
ladle, and the glass pot filled with fresh frit.
The crude glass thus obtained is usually full of bubbles: it is as
hard as common glass: it is of a blackish gray, and more[Pg 196] or less
transparent at the edges. Sometimes it has a whitish colour, and at
others is yellowish or reddish, indicating thereby that the quantity
of charcoal has been too small. Exposed to the air for several weeks,
it undergoes slight changes, which tend rather to improve than injure
its qualities. It attracts a little moisture from the air, which slowly
penetrates its mass without changing its aggregation or appearance,
except that it cracks, and a slight efflorescence appears at its
surface. If after this it be exposed to heat, it swells up, owing to
the escape of the moisture it has absorbed.
In order to prepare the glass for solution in water it must be reduced
to powder by stampers. One part of the glass requires from four to five
of water for its solution. The water is first boiled in an open vessel,
the powdered glass is added gradually, and is continually stirred, to
prevent its adhesion to the vessel. The boiling must be continued for
three or four hours, until no more glass is dissolved. If the boiling
be checked before the liquor has thus attained the proper degree of
concentration, carbonic acid will be absorbed by the potash from the
air, and produce an injurious effect. When the solution has acquired
the consistence of syrup, and a density of 1·24, it is fit for use.
It is then allowed to repose, in order that the insoluble parts may
be deposited: while it is cooling a film forms on the surface, which
after some time disappears, or may be dissolved by depressing it in the
liquor.
Soluble glass being employed only in the liquid state, it is preserved
for use in solution. No particular care is necessary to preserve
the liquid, as, even after a long space of time, it undergoes no
perceptible change, if the solution have been properly prepared. The
only precaution is not to allow too free an access of air to it.
Soluble glass may be prepared by using carbonate of soda, instead of
that of potash. This glass has the same properties as the other, but is
more valuable in its applications. The solutions of these two kinds of
glass may be mixed in any proportion, and the mixture is sometimes more
useful than either of the solutions separately.
The solution of soluble glass is viscid, and when concentrated
becomes turbid or opalescent. The solution unites with water in all
proportions. At a density of 1·28 it contains nearly 28 per cent.
of glass, and if the concentration be carried beyond this point, it
becomes so viscid that it may be drawn out in threads like molten
glass. When the solution is applied to other bodies, it dries rapidly
in the air, and forms a coat like a varnish; a property which leads us
to notice[Pg 197] some of the numerous and varied applications of this curious
preparation.
It is well known that all sorts of vegetable matter, such as wood,
cotton, hemp, linen, paper, &c., are combustible, but in order to burn
them, two conditions are necessary,—an elevated temperature, and
free access of air to supply the oxygen necessary to their conversion
into water and carbonic acid. When once inflamed their own combustion
supplies the heat necessary to the chemical action, provided they be in
contact with the air. If deprived of such contact, and made red-hot,
they will yield inflammable volatile products, but the residual carbon
will not burn, because deprived of air; and thus the combustion will
cease of itself. Such is the property of all the fixed fusible salts,
if they be composed of substances incapable of yielding their oxygen
at a low red heat, either to carbon or hydrogen. Such salts melt as
the vegetable matter becomes healed: they form upon it a coating
impermeable by air, and either prevent or limit the combustion. The
phosphate and borate of ammonia have such a character, but they are so
readily soluble in cold water as to be liable to objections which are
not found in soluble glass. This last-named substance forms a solid
and durable coating, which suffers no change by exposure to the air
(since soluble glass possesses the valuable properly of being almost
entirely unaffected by cold water): it does not involve any great
expense, and is easy of application. But in order that it may not fail,
particular care must be taken, both in preparing and employing it. To
cover wood and other bodies with it the solution must be made of a
pure glass, otherwise it would effloresce and fall off. But still a
slight degree of impurity is not injurious, although after a few days a
slight efflorescence will appear: this may be washed off by water, and
will not occur a second time. When a durable coating is to be applied
to wood, the first solution must not be too strong, for if it be it
will not be absorbed: it will not displace the air from the pores, and
consequently will not adhere strongly. A more concentrated solution
may be employed for the after-coats, but each coat must be dry before
another is applied, and the drying, in the most favourable weather,
will occupy at least twenty-four hours. When the glass is made with
potash the coating is liable to crack: this defect does not apply to
glass made with soda.
Although soluble glass is of itself a good preservative from fire, yet
it fulfils the object better when mixed with incombustible powders,
such as those procured from clay, whiting, calcined bones, powdered
glass, &c. In applying soluble glass to the wood-work of a public
building at Munich, ten[Pg 198] per cent. of yellow clay or yellow earth was
added. After six months the coating had suffered but little change: it
was damaged only in a few places, where it had need of some repair.
This arose from the very short time allowed for the preparation and
application of the glass.
On Veneering.
In our notice of the interior fittings of houses of the better class,
it was stated that the process of veneering is sometimes adopted for
wainscoting. This process is most generally used for articles of
furniture, and deserves to be noticed on account of its ingenuity.
The employment of wood for articles of domestic use or ornament, gives
rise to many departments of mechanical labour, according to the manner
in which the grain of the wood is to be made conspicuous or visible.
In the antique pieces of furniture still existing in old mansions,
the wood employed, such as oak, walnut-wood, mahogany, &c., was
always solid; but in modern times, the desire of making a respectable
appearance, at as small an outlay as possible, has led to the method of
veneering,—that is, making some article of furniture of some
cheap wood,—such as deal,—and then covering it with thin leaves or
sheets of some more expensive and beautiful wood, such as rose-wood,
maple, satin-wood, zebra-wood, pollard oak, &c. So very prevalent has
this custom become, that almost every house now contains some article
of domestic furniture, whose surface is covered with a kind of wood
more valuable than that of which the bulk of the article is made.
It must be obvious, that the mode of procuring or preparing the thin
leaves of veneer calls for great care and nicety, since they are
seldom thicker than a shilling. When the method of veneering was first
introduced, the sawing was effected by hand, in a manner more rude than
the necessities of the case warranted; but when circular saws became
introduced, they were found very efficacious for cutting veneers.
Brunel, in 1805, took out a patent for improvements in the machinery
for sawing timber, in which he employed a large circular saw, composed
of several pieces fitted together, and placed in a frame at such an
elevation that the lower edge was a little below the lower side of the
timber. The timber was placed in a carriage, and moved towards the saw
by a rack.
In such a manner as this veneers are now cut from the timber in this
country. But it is stated that the Russians have devised a very curious
and effective method of cutting veneers, without the use of a saw,
and without making any[Pg 199] waste of material. It is a planing
machine, the action of which is so accurate, that veneers thin enough
for the covering of books, and for lithographic and other engravings,
have been produced; thus serving the place of paper. The operation
is begun by placing the timber from which the leaf is to be cut upon
a square axle, where it is revolved, and made circular by a turner’s
gouge. The blade of a plane of highly-tempered steel, and rather
longer than the cylinder of wood, is fixed at the extremity of a frame
six or seven feet in length, in such a manner as to exert a constant
pressure upon the cylinder, and pare off a sheet of equable thickness,
which folds upon another cylinder like a roll of linen. The frame
to which the blade is attached is moveable at its lower extremity,
and by the action of a weight it depresses in proportion as the mass
diminishes in substance. That this depression may be progressive and
perfectly regular, the inventor has appended a regulator to the machine
consisting of a flat brass plate, preserved in an inclined direction,
upon which the frame descends as the regulator itself is advanced. The
motion is communicated to the cylinder of wood by several cog-wheels,
which are turned by a crank. One hundred feet in length of veneering
may be cut by this machine in the space of three minutes.
When veneers are produced by the action of circular saws, as is now
almost universally the case in England, it is evident that both
surfaces must be rough, from the marks of the serrated edge of the
cutting instrument; and it is in this rough state that they are
purchased by cabinet-makers or others who employ them in veneering
articles of furniture. The operations which are then to be performed
are, to bring the surface of the veneer to a tolerable level, to fix
the veneer to the article of furniture, and to clean and polish it when
so fixed.
Supposing the top of a sideboard to be the article which is to be
veneered. The workman cuts out a piece of veneer, a little larger than
is actually required, to allow for waste; and then lays it flat on
his work-bench. With a veneering plane—which is a small-sized plane,
having an iron jagged with notches like the teeth of a very fine
saw—he works steadily over the whole surface of the veneer, carrying
the plane in the direction of the grain of the wood. The action of this
plane-iron removes all the saw marks, which were irregular in their
course, and gives instead of them a series of regular parallel channels
from end to end of the piece of veneer; these channels are but small in
depth, and their object is to retain the glue which is afterwards used
in the process of veneering.
The surface of the deal or other wood on which the veneer[Pg 200] is to be
laid, is in like manner planed with these parallel indentations; and
then the process of veneering proceeds. The wood, having been well
warmed before a fire, is coated with warm melted glue; and the piece of
veneer is laid down flat on the veneered surface, and rubbed backwards
and forwards, in order that the glue which is between the veneer and
the under-wood may be pressed into all the little grooves produced by
the plane. When the glue begins to get cool, the veneer can no longer
be pressed to and fro, and is then left. This glueing has the general
effect of making the veneer adhere to the foundation beneath; but there
are parts where, from the accumulation of too much glue in one part, or
from the presence of air which had not been expelled by the pressure
of the hands, the veneer rises up as a kind of blister, convex on the
upper surface. The workman employs a veneering hammer to level these
protuberances. This veneering hammer is a piece of wood three or four
inches long, and an inch in thickness, having a straight strip of iron
plate fixed to one edge. The workman, placing the iron edge down upon
the veneer, presses on the block of wood with his hand, and works all
over the surface of the veneer, expressing all the superfluous glue
from the parts which had formed the protuberances. As this redundant
glue must have some place from whence to escape, the workman begins
rubbing at the centre, and thence proceeds towards the edge, at
which the glue finally exudes. There is a curious plan adopted for
ascertaining whether there are any parts, imperceptible to the eye,
where the veneer does not adhere closely to the foundation—viz., by
sound. The workman strikes the veneer all over with a wooden or other
hammer; and if the sound be distinct and solid, he knows that the
proper degree of adhesion has taken place; but if the sound be hollow
and dull, it indicates the existence of a vacant space between the
veneer and the foundation; and a greater degree of rubbing or pressing
is consequently necessary. If the surface of the piece of veneer be of
large dimensions, two workmen are required to level all parts of the
veneer before the glue gets cold and loses its fluidity.
But this operation—however good the glue may be, or however well the
veneer may be pressed down—is not sufficient to cause the veneer to
adhere permanently to the foundation, especially at the edges, where
the air is liable to enter, and to cause the veneer to rise. To prevent
this inconvenience, the veneer, at and near the edges, is kept down,
either by the pressure of heavy weights, or, still better, by the
action of screw-presses. These screw-presses consist of two pieces
of wood or clamps, which are brought to any degree of closeness[Pg 201] by
means of two wooden screws, each screw passing through holes in both
clamps, the handles of the two screws being, respectively to each
other, outside the opposite clamps. The clamps are opened, by means of
the screws, to such a width as to admit the edge of the veneered wood
between them; and the screws are then worked up till the clamps grasp
the wood tightly, where they remain till the glue is quite cold, and
the veneer closely adhering to the foundation.
But even all this care is not in every case sufficient to produce a
firm adhesion of the veneer to the foundation. It frequently happens
that, when the hardened veneered surface is tried with the hammer, a
hollow sound indicates that there is yet a place where the veneer has a
vacancy beneath it. In such a case, the only remedy is one of a curious
kind—viz., to lay a hot iron on the defective part of the veneer,
by which the glue beneath is remelted. A small part of the veneer,
reaching from the defective part to the edge, is also similarly heated,
and the glue beneath remelted. Then, by means of the veneering hammer,
the superfluous glue which had caused the defect is squeezed out, and
pressed to the edges of the veneer through the kind of channel which
had been prepared for it by the heated iron.
Where the surface of the wood to be veneered is more or less
cylindrical, such as a pillar, the front of a drawer, &c., the piece
of veneer has a curvature given to it, corresponding in some degree to
that of the surface on which it is laid, by the action of hot water,
before the glueing is effected. By sponging one side of the veneer with
hot water, it causes that side to swell, while the other side remains
dry; the consequence of which is, that the wetted surface rises into
a convex form, leaving the other side hollow or concave:—this is, in
fact, an instance of warping, where a thin piece of wood is
either unequally heated or damped on opposite sides. The hollow side is
then laid on the glued foundation.
When the veneered surface is dry, its edges are trimmed, and its
surface scraped and sand-papered, preparatory to the finishing
processes which the piece of furniture is to undergo.
Manufacture of Glue.
The preparation of this useful article forms a curious and important
branch of national industry. The chief use of glue is for binding or
cementing pieces of wood together, as practised by the carpenter and
cabinet-maker, in which trades very large quantities are constantly
employed.
Glue (which is nothing more than gelatine in a dry state) is obtained
from the hides, hoofs, and horns of animals; the[Pg 202] refuse of the
leather-dresser, and the offal of the slaughter-house; ears of oxen,
calves, sheep; parings of parchment, old gloves; and, in short, animal
skin and (by a late improvement) bones, are all employed for making
glue.
The first process in this manufacture is to free the materials from
dirt, blood, and other matters which do not afford glue. For this
purpose they are steeped in lime and water, and then placed in baskets,
and rinsed by the action of a stream of water. They are then removed to
a sloping surface, and allowed to drain, and whatever lime remains is
deprived of its caustic property by the reabsorption of carbonic acid
from the atmosphere, since the presence of lime would prove injurious
in the subsequent processes.
The gelatine is removed from the animal matter by boiling. This
process is effected in a somewhat shallow boiler, which is provided
with a false bottom, pierced with holes, and elevated a few inches,
thus serving as a support to the animal matter, and preventing it
from burning by the heated bottom of the boiler. The boiler is filled
about two-thirds with soft water, and then the animal substances are
added: these are piled up above the brim of the boiler, because soon
after boiling commences, they sink down below the level of the liquid.
The contents of the boiler are occasionally stirred up and pressed
down, while a steady boiling is maintained throughout this part of the
process.
As the boiling proceeds, small portions of the gelatine are drawn off
into egg-shells, when, in the course of a few minutes, if the liquid
gelatine becomes, by exposure to the cool air, a clear mass of jelly,
the boiling process is complete,—the fire is smothered up, and the
contents of the boiler left to settle for ten or twenty minutes. The
stop-cock is then turned, and the gelatine flows into a deep vessel,
kept hot by being surrounded with hot water, and thus it remains for
several hours, during which time it deposits any solid impurities. It
is then drawn off into congealing boxes, and prepared as we shall soon
explain.
The undissolved matter in the boiler is treated with boiling water a
second, and even a third time, and the above process continued until
nothing more can be extracted. The subsequent solutions are often too
weak to be made into glue, but they are economically used with fresh
portions of animal matter.
A clear idea may be formed of this part of the manufacture by the
annexed illustration, which represents a section of three vessels, on
different levels. The uppermost vessel, which is heated by the waste
heat of the chimney, supplies warm water to the animal matter contained
in the second[Pg 203] vessel: the third vessel receives the liquid gelatine,
and retains it in a fluid state, while the solid impurities are being
deposited.
The gelatine is drawn off from this third vessel into buckets, and
conveyed to the congealing boxes. These boxes are of deal, of a square
form, but somewhat narrower at bottom than at top. The liquid glue is
poured through funnels, provided with filter-cloths, into the boxes
until they are entirely filled. This process is conducted in a very
cool and dry apartment, paved with stone and kept very clean, so that
any glue which may be spilt may be recovered. In twelve or eighteen
hours the liquid glue becomes sufficiently firm for the next process,
which is performed in an upper story, furnished with ventilating
windows, so as to admit air on all sides. The boxes are inverted on a
moistened table, so that the cake of jelly may not adhere to it: this
cake is cut into horizontal layers, by means of a brass wire, stretched
in a frame, and is guided by rulers, so disposed as to regulate the
thickness of the cake of glue. The slices thus formed are carefully
lifted off, and placed on nets stretched in wooden frames. As these
frames are filled they are placed over each other, with an interval of
about three inches between every two frames, so that the air may have
free access. Each frame is so arranged as to slide in and out like a
drawer, to allow the cakes to be turned, which is done two or three
times every day.
An experienced writer on manufactures thus observes, concerning this
part of the process:—“The drying of the glue[Pg 204] is the most precarious
part of the manufacture. The least disturbance of the weather may
injure the glue during the two or three first days of its exposure.
Should the temperature of the air rise considerably, the gelatine
may turn so soft as to become unshapely, and even to run through the
meshes upon the pieces below, or it may get attached to the strings
and surround them, so as not to be separable without plunging the
net into boiling water. If frost supervene, the water may freeze,
and form numerous cracks in the cakes. Such pieces must immediately
be remelted and reformed. A slight fog even produces upon glue newly
exposed a serious deterioration, the damp condensed upon its surface
occasioning a general mouldiness. A thunder-storm sometimes destroys
the coagulating power in the whole laminæ at once, or causes the glue
to turn on the nets, in the language of the manufacturer. A wind
too dry or too hot may cause it to dry so quickly as to prevent it from
contracting to its proper size, without numerous cracks and fissures.
In this predicament the closing of all the flaps of the windows is
the only means of abating the mischief. On these accounts it is of
importance to select the most temperate season of the year, such as
spring and autumn, for the glue manufacture.”
When the glue is properly dried a gloss is imparted to each cake, by
dipping it in hot water, and passing over it a brush, also wetted
with hot water. The cakes are then placed on a hurdle, dried in the
stove-room, or in the open air, if the weather be sufficiently dry and
warm. It is then packed in casks for sale.
It has been found by experiment that when two cylinders of dry ash, one
inch and a half in diameter, were glued together, and after twenty-four
hours torn asunder, a force of 1260 pounds was required to produce the
separation, thus making the force of adhesion equal to 715 pounds per
square inch. Another experiment made the force of adhesion to equal
4000 pounds on the square inch.
The House-Decorator of Italy.
In an interesting notice, by Wilson, of the present state of
the arts in Italy, read before the Society of Arts, in Scotland,
in November, 1840, a few details are given of the skill with which
the house-builder converts the commonest materials into tasteful
decorations. The following is an abstract of that part of the notice
which relates to the subject of the present volume:—
Notwithstanding the comparatively small employment afforded to Italian
architects in the present day, yet there[Pg 205] can be no question as to the
skill displayed in erecting their designs. The masonry is excellent,
and the ancient Roman brick-work is rivalled by that of the present
generation; houses are built of brick, in which all the exterior
decorations are moulded in that material as perfectly as if executed in
stone. The skill with which the Italian workmen build in brick, may be
exemplified by the Florentine practice of arching over rooms without
centering of any description. Two thin moulds of board, the shape of
the intended arch, alone are used: these are placed at each end of the
apartment which it is intended to cover in, and pieces of string are
stretched from the one to the other, guiding the workman as he advances
in the formation of his arch, which he builds, uniting the bricks by
their thin edges (greatly thinner than those we use), and trusting
entirely to the tenacity and quick-setting of the cement.
Plastering is also carried to a perfection in Italy, of which we have
very little idea in this country; rooms are so exquisitely finished,
that no additional work in the shape of house-painting is required; but
the polish of the plaster, and its evenness of tint, are such as to
rival those of the finest porcelain. Sometimes the plaster is fluted,
or various designs are executed in intaglio upon it, in the most
beautiful manner. Scagliola, a very fine preparation from gypsum, is
the material chiefly used. An instance of the cheap rate at which this
work is done, is afforded in the new ball-room in the Palazzo Pitti
grand-ducal residence at Florence, which, including mouldings, figures,
bas-reliefs, and ornaments, was executed at a cost of two crowns for
every four square feet.
A most beautiful art among the Italians, and one which might be
advantageously introduced into this country, is that of making what are
termed Venetian pavements. This method of finishing the floors of rooms
is conducted in the following manner. In the first place a foundation
is made of lime mixed with pozzolana, and small pieces of broken stone;
this is, in fact, a sort of concrete, which must be well beaten and
levelled. When this is perfectly dry, a fine paste, as it is termed
by the Italians, must be made of lime, pozzolana, and sand; a yellow
sand is used which tinges the mixture; this is carefully spread to a
depth of one or two inches, according to circumstances. Over this is
laid a layer of irregularly broken minute pieces of marble of different
colours, and if it is wished these can be arranged in patterns. After
the paste is completely covered with pieces of marble, men proceed to
beat the floor with large and heavy tools made for the purpose; when
the whole has been beaten into a compact mass, and the paste appears
above the pieces of marble, it is[Pg 206] left to harden. It is then rubbed
smooth with fine-grained stones, and is finally brought to a high
polish with emery powder, marble dust, and lastly, with boiled oil
rubbed on with flannel. This makes a durable and very beautiful floor,
which in this country would be well adapted for halls, conservatories,
and other buildings.
The carpentry of the Italians, as observable in ordinary houses,
displays little skill and indifferent workmanship, but in the roofs
and floors of important buildings, they satisfactorily prove their
knowledge of scientific principles, and several of their designs are
well known to British architects.
With regard to the working of iron, in comparison with our system, the
Italian is primitive indeed; yet at times he can and does produce very
good specimens of workmanship, but at a heavy cost; consequently they
are generally content with very ordinary productions. A manufactory
of wire, and of driving and screw nails, by means of machinery, now
occupies the villa of Mecænas at Tivoli; the articles produced are
very well made. Copper is extensively used in Italy, and there are
productive mines in the . The workmanship of
articles made of this metal is respectable; various utensils are
made of brass in a neat and satisfactory manner, but in the interior
finishing of houses, if much nicety is required, articles of foreign
manufacture are used.
House-painters may be mentioned in the last place, and these display
much taste and skill; and there is a class of them who greatly excel
those in this country, having more the feeling and taste of artists.
Surrounded by the finest models in this art, the Italian decorator
enjoys every advantage in its study, and he inherits besides from the
best periods of art, or rather from antiquity, taste, and a good system
of workmanship. He is not a mere machine, employed in the use of the
moulds, stamps, and other mechanical contrivances, which too often keep
the decorative arts within such narrow limits.
Fresco Painting.
The proposed introduction of Fresco Painting into our public buildings
will, it is hoped and expected, have the effect of employing the artist
in fresco upon the walls of our dwelling-houses. Already have a few of
the mansions of our nobility been thus decorated, and in anticipation
of its general introduction it may not be out of character with this
little work to describe the process in detail.
Respecting the origin of the term fresco there are two opinions;
according to some the term is said to have been[Pg 207] adopted because the
practice of it is used in the open air. Thus in the Italian language,
signifies “to take the air;” or “to walk abroad
in the air;” but a more probable explanation is to be found in another
meaning of the word fresco, viz., “new,” or “fresh,” as applied to the
state of the plaster in which it is wrought. The artist traces his
design, colours it, and completely finishes in one day so much of his
picture as will occupy the wet plaster ground that has been prepared
for him, so that when the ground is dry, he may not retouch any part
of his work. This is the characteristic distinction of painting in
fresco—a method by which the painting is incorporated with the mortar,
and drying along with it becomes extremely durable, and brightens in
its tones and colours as it dries.
It will therefore be readily conceived that the artist in fresco has
to encounter difficulties of no ordinary kind; a few of them are thus
noticed by a writer in Rees’s :—“From the
necessity there is in the progress of this style of art, that it should
be executed with rapidity, and from the impossibility of retouching
it without injuring the purity of the work, the artist, unless he be
endowed with very extraordinary powers of imagination and execution
indeed, is obliged to prepare a finished sketch of the subject, wrought
to its proper hue and tone of colour, and so well digested, that there
may be no necessity for making any essential alterations in the design.
This, which is a very useful mode of proceeding in all fine works of
painting, is absolutely indispensable in fresco, to those who are
not determined to give the rein to their ideas, and leave as perfect
whatever may first present itself. There is no beginning in this, by
drawing in the whole of the parts at one time, and correcting them at
leisure, as is the custom with oil-painters, who may therefore proceed
to work without a sketch; here all that is begun in the morning must
be completed in the evening; and that almost without cessation of
labour, while the plaster is wet; and not only completed in form, but
also, a difficult, nay, almost impossible task, without a well-prepared
sketch, must be performed, viz., the part done in this short time must
have so perfect an accordance with what follows, or has preceded, of
the work, that when the whole is finished, it may appear as if it had
been executed at once, or in the usual mode, with sufficient time to
harmonize the various forms and tones of colour. Instead of proceeding
by slow degrees to illuminate the objects, and increase the vividness
of the colours, in a manner somewhat similar to the progress of nature
in the rising day, till at last it shines with all its intended effect,
which is the course of painting in oil,[Pg 208] the artist working in fresco
must at once rush into broad daylight, at once give all the force in
light, and shade, and colour, which the nature of his subject requires,
and this without the assistance (at least in the commencement) of
contrast to regulate his eye; so that here, as has been said, a well
digested and finished sketch seems indispensably requisite.”
The custom of decorating walls with paintings is very ancient. Those
discovered by Belzoni, among the royal tombs of Egypt, prove the
existence of the art among the Egyptians many centuries before the
Christian era. There is also abundant evidence that it was practised
by the Etruscans and Romans. But the more common practice up to the
time of Augustus seems to have been to paint the walls of houses of
one single colour, and to relieve this with fantastic ornaments.
According to Pliny, Augustus was the first to suggest the covering
of whole walls with pictures and landscapes. About the same time a
painter named Ludius invented that style of decoration, now called
arabesque or grotesque, many beautiful examples of which
have been discovered at Pompeii and other places. The invention of the
Arabesque style, as its name implies, has been improperly claimed for
the Arabians of Spain; whose religion forbidding the representation of
animals, they employed foliage, stalks, stems, tendrils, flowers, and
fruit, in a variety of forms and combinations, with which they adorned
the surfaces of their buildings. Hence the fanciful combinations of
natural objects occupying a flat surface came to be called Arabesque,
although it differed so much from the Mohammedan compositions as to
contain animals real or fabulous. That the term is badly chosen,
especially as applied to the fanciful enrichments on the walls of
Pompeii, &c., will be seen from the fact that such ornaments were
invented and executed long before the sons of Ishmael had learned to
draw. The term grotesque is less objectionable: it is derived from
the subterranean rooms (grotte) in the baths of Rome, in which those
specimens of ancient art were found, from which Raphael derived the
plan of the beautiful frescos which adorn the piers and pilasters of
the arcaded gallery of the palace of the Vatican, called, in honour of
the artist, “Le Logge di Raffaelle.”
The practice of Fresco Painting may be conveniently considered under
the following heads:—1. The cartoon. 2. The preparation of the wall.
- The process of painting. 4. The colours and implements. The methods
as adopted by different artists are of course subject to variation; but
as general principles are not altered by variations in those details
which conduce to the same end, so the following[Pg 209] may be taken as an
accurate exposition of the practice of the art.
1. The Cartoon. Since the artist cannot without injury retouch a fresco painting, it is necessary that every part of the design be decided on by preparatory sketches finished of the full size, from which the fresco may be transferred, by tracing to the wall. When the painting is very large, the whole composition of the full size is sometimes divided into two or more cartoons.
In the preparation of a cartoon, a strong cloth is stretched on a frame, as if to be prepared for painting; paper is then firmly glued on the cloth. When this is dry, a second layer of paper is attached by glue. The edges of the separate sheets, where they overlap, are scraped, so as to preserve an even surface. The surface is then prepared for drawing with size and alum.[7] The drawing is made with charcoal, and when finished is fixed by wetting the cloth at the back with cold water, and then steaming the drawing in front. The steaming is performed with a tea-kettle with two or three spouts, kept boiling by the flame of a spirit lamp; by this means the charcoal is incorporated with the melted glue, and a solid surface like that of a picture is produced.
From this finished drawing the outline is traced on oiled paper. As much of this working outline as can be finished in one painting is then nailed to the wet wall, and the forms are again traced with a sharp point, whereby an indented outline is produced on the soft plaster. According to another method, the paper to be applied to the wall is placed behind and in close contact with the finished cartoon; the outlines of the latter are then pricked, and a similar pricked outline is thus produced on the paper behind. This pricked paper is then made the working drawing: it is fastened to the wall, and dusted with a little bag filled with black or red dust; this leaves a dotted outline on the wall. This method is sometimes adopted for small works, and the advantage of it is that it leaves the surface of the plaster undisturbed. The first mode is, however, generally preferred; since it insures the best and most decided outline, and preserves the finished cartoon uninjured.
Cartoons prepared for fresco may be seen in the National Gallery: those at the head of the staircase are by Agostino Caracci. In one of these (the Triumph of Galatea) the pricked outline is very apparent; as also in the fragment of the Cartoon by Raphael, (the Murder of the Innocents,) also[Pg 210] in the National Gallery. In many celebrated Italian frescos the indented outline, produced by tracing, is apparent.
In addition to the cartoon it is desirable to have a coloured sketch of the whole composition.
2. The preparation of the Wall. The greatest obstacle to the permanence of fresco painting is damp: hence, if the wall to be painted is covered with old mortar, the ingredients of which are unknown, this coat should be entirely removed until the solid brick or stone is laid bare. The rough coat then applied is composed of river-sand and lime, and of such thickness as is generally used in preparing the walls of dwelling-houses. The surface of this coat should be rough, but not uneven. Thus prepared, the wall should be suffered to become perfectly dry and hard; the longer it remains in this state the safer it will be, especially if the lime used was in the first instance fresh. In that case two or three years should elapse before the process of painting is commenced.
The preparation and seasoning of the lime is one of the essential conditions of fresco painting. At Munich it is made and kept as follows:—A pit is filled with clean burnt limestone, which is slaked, and then stirred continually till it is reduced to an impalpable consistence. The surface having settled to a level, clean river-sand is spread over it to the depth of a foot or more, so as to exclude the air, and, lastly, the whole is covered with earth. It is allowed to remain thus for at least three years before it is used, either for the purposes of painting (lime being the white pigment) or for coating the walls.
The last preparation for painting on the mortar, is as follows:—The surface is wetted with pure water, till it ceases to absorb. A thin coat of plaster is then spread over that portion only which is to be painted: the surface of this coat should be moderately rough. As soon as it begins to set (i. e., in about ten minutes or so, according to the temperature) a second thin coat is laid on, and the surfaces are smoothed with a wooden trowel. Some painters like to work on a perfectly smooth surface, in which case the last coat is polished by applying a piece of paper on the surface, and passing the trowel over it. When a small amount of roughness is required, a dry brush, or a piece of beaver nap attached to the trowel, is passed over the plaster in all directions.
3. The process of Painting. The wall being properly prepared, the outline of the figures is to be traced with a sharp point on the plaster, as before described. The artist commences his work when the surface is in such a state that it will barely receive the impression of the finger, and not so wet as to allow the colours to run or to be liable to be stirred up[Pg 211] by the brush. If the wall has been previously well wetted, it will in general not dry too rapidly; but if in warm weather the surface becomes too hard to imbibe the colour properly, a small quantity of water is from time to time sprinkled over the surface.
The colours being ground fine in water, and the most useful tints abundantly supplied, they are arranged in pots or basins, and several palettes with raised edges are ready at hand to work from. A few pieces of tile or some absorbent material are provided to prove the tints upon, because all colours ground in water become much lighter when dry than they appear when wet. The brick absorbs the water, and leaves the colour nearly in the state in which it will appear upon the wall.
The first tints that are applied sink in and have a faint appearance; it is therefore necessary to go over the work several times before the full effect is produced: but after some time the last edition of colour will not unite with that already applied unless the part be again wetted.
At the close of a day’s work, any portion of the prepared plaster which remains over and above the finished part is to be cut away, care being taken to make the divisions at a part where drapery, or some object or its outline, forms a boundary, for if this be not attended to, the work will appear patchy. The next day, in preparing a new surface, the edges of the previously painted portion must be carefully wetted so as to ensure a perfect junction of all the parts of the painted surface.
At Munich the artists have a contrivance for arresting the drying of the work should they be unable to finish the day’s allotted portion. A piece of fine linen is wetted and spread over the fresh plaster and painting, and pressed to the surface by means of a cushion covered with waxed cloth.
Defects are sometimes remedied by cutting out the objectionable portion, and painting it anew upon a fresh surface of plaster. In the finished fresco, shadows are sometimes deepened, parts are rounded, subdued, or softened by hatching in lines of the colour required, mixed up with vinegar and white of egg. Crayons made of pounded egg-shells are sometimes used to heighten the lights. But all these additional amendments are highly objectionable; they impair the durability of the fresco, and in the open air these retouchings are useless, because the rain washes them away, whereas it has no influence upon frescos painted without retouching.
4. The Colours and Implements. The colours employed in fresco painting are few and simple. They consist chiefly of earths and a few metallic oxides variously prepared. No[Pg 212] animal and vegetable substances can be used, because the lime would destroy them. The brushes are of hog’s hair, but longer than those used in oil painting. Small pencils of otter hair are also used; no other hair being found to resist the lime. Pure distilled water ought to be employed in all the operations of this art.
Such is the process of fresco painting, the details of which, after the above statement, will be rendered more intelligible by the following abridged account of a visit, by Andrew Wilson, to the royal palace at Genoa, to see the Signor Pasciano paint a ceiling in fresco:—
The artist had prepared his tints upon a table with a large slate for the top: they consisted of terra vert, smalt, vermilion, yellow ochre, Roman ochre, darker ochre, Venetian red, umber, burnt umber, and black. These colours were all pure, mixed with water only, and rather stiff. He mixed each tint as he wanted it, adding to each from a pot of pure lime, or from one containing a very pale flesh tint. A lump of umber served to try his colours on. He used a resting-stick with cotton on the top to prevent injury to the prepared wall, or intonaco, as the Italians call it. The moment this surface would bear touching, the artist began to work upon the figure, the outline of which had just been traced. The head was that of the Virgin. The artist began with a pale tint of yellow round the head for the glory: he then laid in the head and neck with a pale flesh colour, and the masses of drapery round the head and shoulders with a middle tint, and with brown and black in the shadows. He next, with terra vert and white, threw in the cool tints of the face; then with a pale tint of umber and white, modelled in the features, covered with the same tint the part where the hair was to be seen, and also indicated the folds of the white veil. All this time he used the colours as thin as we do in water colours; he touched the intonaco with great tenderness, and allowed ten minutes to elapse before touching the same spot a second time. He now brought his coloured study, which stood on an easel near him, and began to model the features, and to throw in the shades with greater accuracy. He put colour in the cheeks, and put in the mouth slightly, then shaded the hair and drapery, deepening always with the same colours, which became darker and darker every time they were applied, as would be the case on paper for instance. Having worked for half an hour, he made a halt for ten minutes, during which time he occupied himself in mixing darker tints, and then began finishing, loading the lights, and using the colours much stiffer, and putting down his touches with precision and firmness: he softened with a brush with a little water in it.[Pg 213] Another rest of ten minutes; but by this time he had nearly finished the head and shoulders of his figure, which being uniformly wet, looked exactly like a picture in oil, and the colours seemed blended with equal facility. Referring again to the oil study, he put in some few light touches in the hair, again heightened generally in the lights, touched too into the darks, threw a little white into the yellow round the head, and this portion of his composition was finished, all in about an hour and a half. This was rapid work, but it will be noticed that the artist rested four times, so as to allow the wet to be sufficiently absorbed into the wall to allow him to repass over his work. He now required an addition to the intonaco; the tracing was again lifted up to the ceiling, and the space to be covered being marked by the painter, the process was repeated, and the body and arms of the figure were finished.
On the occasion of a second visit, Wilson remarked that the artist had cut away from his tracing or cartoon those parts which he had finished upon the ceiling: that the tracing was in fact cut into several portions, but always carefully divided by the outline of figures, clouds, or other objects. These pieces are nailed to the plaster, so as to fold inwards or outward for the convenience of tracing the outlines. The artist was now about to proceed with a group of figures. Having gone over the outline carefully with a steel point, he waited till the intonaco became a little harder, and in the mean time mixed up a few tints; he then commenced with a large brush, and went over the whole of the flesh; he next worked with a tint which served for the general mass of shadow, for the hair, and a slight marking out of the features. He now applied a little colour to the cheeks, mouth, nose, and hands, and all this time he touched as lightly as possible. He then paused for ten minutes, examined his oil study, and watched the absorption of the moisture.
The intonaco would now bear the gentle pressure of his fingers, and with the same large brush, but with water only, he began to soften and unite the colours already laid on. He had not as yet used any tint thicker than a wash of water-colour, and he continued to darken in the shadows without increasing the force or depths of colour. The artist now increased the number of his tints; he made them of a much thicker consistence, and he now began to paint in the lights with a greater body of colour, softening them into the shades with a dry brush, or with one a little wet, as was required. In drying, the water comes to the surface and actually falls off in drops, but this does no harm, although, as Wilson remarks, it sometimes looks alarming.
[Pg 214]
The effect of fresco painting is described as being exceedingly beautiful. It does not require for the production of its general effect those particular and concealed lights which the shining surface of an oil-painting renders necessary. Fresco is seen entire in any situation and by any light, even by artificial light, which perhaps shows it best. Severn was much struck by the increased beauty and power of the Caracci frescos at Rome by artificial light. Even a dim or diminished light does not destroy their effect.
“It must have been for this reason that Raphael adopted fresco in the Vatican, after he had made experiments in oil; for the rooms are so ill-lighted, that oil pictures could never have been seen at all; and it is surprising to find such fine works in such a place. Three sides of the rooms are illuminated merely by the reflected light from the great wall of the Sistine chapel, yet this beautiful and luminous material of fresco is so brilliant in itself, that the pictures are well seen. Nine of them were painted without a ray of real light, and have always been seen in the same way. I think this is a very important consideration; for as we have but a diminished light at any time, it is most necessary to adopt a manner of painting suited to it, which can be seen at all times.”
Fresco does not seem to be at all understood in this country; it is generally confounded with scene painting; it is a common mistake to suppose that the cartoons of Raphael are the same as his frescos. It is often confounded with distemper painting, which is done on a dry ground, and does not admit of richness of colour.
“This will be clearly understood (writes Severn) by those who have had the good fortune to see Raphael’s and Guido’s frescos at Rome, which for colour are exquisitely beautiful, and even powerful in all the fascinations of this part of the art, presenting to us still greater varieties than oil painting can pretend to; excelling in all the delicate effects of atmosphere, from the gorgeous daylight, the air of which you seem to breathe in a fresco picture, down to the silvery flitting charm of twilight. In these particulars, it reminds us of English water-colour effects. Then I should mention the magnificence of fresco landscape, and of landscape backgrounds, particularly by Domenichino, in which not only the characters, but the movements of trees, are always rendered in a way which I have rarely seen in oil colours…. Then I must remind you of the grandeur of colour and effect in Michael Angelo’s frescos on the ceiling of the Sistine chapel. What oil could ever have approached such things? When he said ‘that oil painting was only fit for women and children,’ he meant on account of the labour and difficulties of the[Pg 215] material compared with fresco. We are assured he performed this gigantic labour in twenty months, without the usual assistance of colour-grinders or plasterers, but alone with his own hand. There are on this ceiling fourteen figures, of at least forty feet in stature, and nearly five hundred figures, the least of which are double the size of life. While we regard this as the most extraordinary example of individual human power, we must consider that it was only in the simplicity and ease of the fresco material that Michael Angelo could have accomplished such a stupendous work. The preparation of oil colours, varnishes, &c., would alone have occupied the twenty months.”
The small cost and great durability of frescos are not the least of their advantages. It was feared that the smoke of London would soon destroy our frescos, but Professor Hess stated that “if frescos were painted in the open air in London, the rain would be the best picture-cleaner.” Indeed, competent authorities agree that pure water and a soft sponge are the best means for cleaning frescos from the effects of smoke. That the change effected by time on the colours is to increase their effect. The great enemy to fresco is a wall constitutionally damp, in which lime in too new a state has been employed, or new timber or imperfectly burnt bricks. The nitre which sometimes accumulates on walls is also very destructive.
Nor are frescos such permanent fixtures as is generally imagined. Some ingenious Italians have succeeded perfectly in removing large frescos from one wall and applying them securely to another. The colours in fresco do not penetrate very deep, and the thin layer of pigment and lime of which the painting consists, may be removed by glueing several layers of calico to the wall: a slight force is then sufficient to detach the painting: it is removed to its new bed, and when firmly attached, the cloths and glue may be removed by warm water.
We must now leave the Reader in possession of the dwelling-house which we have endeavoured to build for him. If we have not furnished it, or described the modes in which the various articles of furniture are made, it was not because the subject is devoid of interest, far from it; but because we were anxious not to injure the completeness and interest of the preceding details by attempting too much within the limits of this little volume.
FOOTNOTES:
[7] The term Cartoon is derived from , the augmentative of , the Italian for paper.
LONDON:
SAVILL AND EDWARDS, PRINTERS,
CHANDOS STREET.
Transcriber’s Notes
In a few cases, obvious errors in punctuation have been fixed.
Page 28: “the standstones of which” changed to “the sandstones of which”
Page 141: “the vessel e” changed to “the vessel c”
Page 213: “upon the cieling” changed to “upon the ceiling”
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