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I am as much superior to thera as Jove is superior to the rest of the deities: I am constructed of bricks, made from mnd, which adhered to the ends of poles, and was drawn up from the bottom of the lake."
Unburnt bricks were used in the walls of Athens, and in the construction of several Grecian temples and palaces. Vitruvins expressly describes the manner in which these bricks were made, and the proper se:tsous for drying them regularly; namely, spring raid autumn. The inhabitants of Utica made use of such bricks only as were five years old, and had been approved by a magistrate.
The Romans made use of bricks to a far greater extent than the Greeks, as the remains of their public edifices plainly show: some of their brick structures raised 1,700 years ago still remain as entire as when first built. To that people, doubtless, we are indebted for the introduction of the art into Britain. But the use of brick does not appear to have become general in this country until after the Norman conquest, nor to have attained any remarkable degree of perfection until so late as the reign of Henry VIII., when many interesting buildings were constructed of this material, in a style which has made them objects of admiration in our own age. Yet it was only for the more important edifices that brick was solely used; the ordinary houses consisted of a frame-work of timber, either filled in with lath and plaster, or with bricks introduced in panels. The danger of so great use of timber in a crowded city became evident when the great fire of London desolated the homes of the metropolis, and after that event, it was wisely ordained that brick should be the material of the future city, and that even the ornamental part of the houses should be contrived in the same material. Thus, brick-work came to be carved and made to assume the forms which more properly belong to stone, such as Doric pillars, and rich entablatures curiously wrought with the chisel subsequent to the erection of the walls. In Holland the art of making very durable bricks was practised at an early period, the floors and pavements being constructed of that material. These remain uninjured for a surprising length of time, and exhibit the superior quality of the brick. English bricks are decidedly inferior to these, not on account of any defect in the materials, but on account of the saving of labour and fuel which is sought after in the majority of cases, and which is rendered necessary by the mania for cheapness. The system prevailing in the metropolis fosters this mania, for the great majority of the lands arc let on building leases, and it is to the interest of the builder to erect houses which shall merely last out the lease, since, at the expiration of that period they become the property of the landlord.
The operations connected with ordinary brickmaking are briefly these: digging the clay in autumn; leaving it to mellow by frost during winter, the masses being frequently turned and broken up, to expose them more completely to the action of the
atmosphere: throwing the crumbled clay in spring into shallow pits, where it is watered and soaked: then tempering the clay by treading and kneading by the feet either of men or oxen, or by means of a horsemill: next conveying the kneaded clay to the bench of the moulder, who takes a lump and dashes it into a wooden or iron mould, striking off the superfluous clay with a strike or smooth piece of wood. The bricks are delivered from the mould, and ranged on a barrow or on the ground, until they are firm enough to bear handling, when they are trimmed with a knife. They are then built up in long dwarf walls, with sufficient space for the air to penetrate in every direction: these walls are thatehed as a protection from the weather, and thus the bricks are left to dry until they are in a proper state to be consigned to the kiln.
The various argillaceous earths used in brickmaking are generally mixed with some other substance, being for the most part unfit to be used alone. Some are almost pare clay or alumina, and are strong, and exceedingly plastic, but cannot be dried without splitting. Others, being light sandy clays or loams, are too loose to be made into bricks without the admixture of lime as a flux, to bind the materials together. Others again are natural compounds of alumina and silica; but these if free from lime, magnesia, or metallic oxides, are exceedingly valuable clays, being from their infusible nature adapted for making fire-bricks for lining furnaces, for making crucibles, glass-house pots, &c. Fire-clay is found throughout the coal-measures, and occurs in abundance, and of excellent quality, at Stourbridge, and also in the vicinity of Neweastle and Glasgow.
Bricks for ordinary uses are known as "placebricks," "grey and red stocks," "marl-facing bricks," and "cutting bricks." The place-bricks and stocks are the ordinary wall bricks. The marls are very superior bricks, made in the neighbourhood of London, and used on the outside of buildings. The finest kind of marls and red bricks are called cutting bricks, and arc used in arches over doors and windows, being rubbed to a centre and gauged to a height. The red bricks made of Hedgerly loam, from a village of that name, near Windsor, are used as fire-bricks about furnaces and ovens. Foreign bricks are Dutch and Flemish bricks and clinkers: they are similar in quality, and of a dirty brimstone colour. The first two are used for paving yards, stables, &c., and the clinkers which are most baked arc used for ovens. Place-bricks are also used in paving dry, or laid in mortar, and they are put down flat or edgewise. If they are laid fiat, 32 of them will pave a square yard; if edgewise, twice that number are required. Ventilating bricks are an invention of modern times. They are double the size of common bricks, although they contain only the same quantity of clay. They are hollowed out at the sides, so that when two are placed side by side, a circular opening is left between them, which, when tiers of similar bricks are laid on, forms of course a tube within (lic wall, and this may be applied to the purpose of either warming or ventilation.
The first process in brick-making is the tempering of the clay, which, as we have said, is the work of early spring, after it has lain exposed to the frost during winter. Great care is then taken as the clay is being turned over and tempered with water, to remove by hand every stone that can be discovered in the plastic mass; for the presence of even a small pebble in a brick causes it to crack in drying. Of course this hand-picking is impossible where much gravel occurs: in such cases the clay must be washed in a trough filled with water, until it becomes liquid enough to pass off through a grating into pits prepared for its reception; the gravel meanwhile being retained by the grating. In districts where veins of skerry or impure limestone abound, it is found desirable to grind the clay between rollers, which crush the limestone, and thus obviate the evil which arises when even a small piece of this substance remains in a brick, and by the carbonic acid driven off from it in burning, forces a hole in the brick, and destroys its usefulness.
i'or the marl, or malm bricks, made near London, and used for the best outside work in houses, the clay is dug in autumn, ground to a pulp at once in a wash-mill, and mixed with chalk previously ground to the consistence of cream. This pulp is run off through gratings, and allowed to settle until it is firm enough for a man to walk upon it: it is then covered with finely-sifted ashes, and allowed to remain all the winter to mellow. In the spring the ashes are thoroughly mixed with the clay and pugged in a pug mill. This is a conical wooden tub, having the larger end upwards, with an npright revolving shaft passing through it, armed with a number of knives, which cut and knead the clay, and force it through the mill, which is constantly filled at the top from the barrows of the work-people, while the clay
is still performed by the treading of men's naked feet, which become by constant practice sensitive to the slightest roughness in the mass, and able to detect the smallest stone or impurity.
When the clay has been reduced by one of these processes to the necessary state for brick-making, masses of it arc successively brought to the moulder's bench. The mould is without top or bottom, and the workman's art consists in dashing a piece of clay with such force into it, as completely to fill it, and then cleverly striking oil' the superfluous quantity, and turning out the brick on a pallet, which is placed by a boy on a hack-barrow, which when loaded is wheeled away to the hack-ground, where the bricks are built into long low walls to dry. By another plan, the bricks are shifted at once from the moulder's bench to a drying floor, from thence to the hovel, or drying shed, and from the hovel to the kiln.
The moulder's bench is a rude kind of table, ofton provided with a trough for wafer, as well as a heap
Fil/. 2Z<i. Uoulder'i ReKca
>jf sand, the mould being either dipped in water, or sanded, between the making of each brick, that the clay may not adhere. If water is used, the process is commouly called stap-moulding, if sand, palletmoulding. In the neighbourhood of London, women commonly take part in the operations. Fig. 236 represents a woman thus engaged. The moulds were J formerly of wood only; they arc now sometimes made of brass, cast in four pieces, and riveted together, or of wood lined with brass, sometimes of wood with the edges of iron, sometimes with the two longest sides of iron. Brass moulds do not require wetting or sanding; but they are expensive, and the edges soon become worn. Wooden moulds therefore continue in some districts to be largely used. A good form of mould is a wooden mould lined with brass; the wood as well as the brass being in four pieces, and attached by rivets at the angles. This mould costs about twenty-five shillings, and was formerly still more expensive. The brass overlaps the wood at the edges, where it wears out rapidly, and the cost of repair is nearly as much as the original price of the mould. Fig. 237 represents a
Fi}. 238. HACI-RARROW.
represents the bricks on one set of pallets, ranged on the hack-barrow, which has a flat top of light framework, fit to receive two rows of bricks, thirteen in each row. Three of these barrows are required for use at each moulder's bench, one being constantly loading there, another unloading in the drying ground, and the third being wheeled to and fro. The low walls of bricks in the drying ground are called barks. These are built two bricks wide, and eight bricks high, and the bricks are generally placed slanting, and not at right angles to the length of the wall. When the bottom row of one hack is formed, the workman begins a second hack, leaving the first to get firm before it has to bear the weight of a second row. Plenty of straw or hay is at hand to cover up the bricks at night, or in bad weather. For the finer descriptions of bricks, drying under cover is adopted, and in some instances flues are carried under the floors of the drying sheds, and currents of air are carefully exclnded.
Where the demand for bricks is very large, brick
"lding is performed by machinery. A number of
machines have been invented for this purpose, and
some of them have answered the end very well.
But it is doubtful whether the pressure employed is really an advantage. The density of the bricks is thereby increased, and they are smoother, heavier, and stronger than other bricks, which for some purposes is desirable, but they do not adhere so well to the mortar, they are difficult to dry well, and their weight adds to the expense of carriage, and prevents the workman from laying so many in a given time, as of the hand-made bricks. Machine-made bricks are also frequently disfigured by a ridge caused by the clay rising a little way up the sides of the piston, in the space which, without careful workmanship, is apl to occur between the piston and the mould.
Two brickmaking machines much in favour in this country are Ainslie's and Hunt's. The latter has been extensively used in the execution of large contracts, and consists of two cylinders, each covered with an endless web, which are so placed that they form a sort of hopper on their two upper cylindrical surfaces, the ends being enclosed by two iron plates. The tempered clay is thrown into this hopper, and at the lower part it acquires the form and dimensions of a brick. Beneath is worked an endless chain, by the movement of the cylinders, and at various marked intervals are laid the pallet-boards under the hopper; the clay is brought down by a slight pressure, and enters a frame, which has a wire stretehed across it, which projects through the mass, and cuts off the requisite thickness; this is immediately removed by the forward motion of the endless chain; and this operation is renewed as often as a new pallet-board is advanced under the hopper. Such a machine produces about 1,200 bricks per hour, and is worked by two men and three boys. By this plan less pressure is given than in most machines, consequently the bricks are less difficult to dry equally. Machine-work is cheaper than hand-labour in the moulding of bricks.
Machinery has been recently employed for making bricks and other articles of clay nearly in the state of a dry powder. The clay is subjected to heavy pressure in strong metal moulds, and is by this means reduced to one-third its original thickness. It retains just sufficient moisture to give it cohesion, and the bricks thus formed can be handled at once, and taken direct to the kiln. This method was devised by Mr. Prosser of Birmingham, and is highly useful for making ornamental bricks, floor-tiles, &c. By an experiment made on a nine-inch brick of this sort, it was found that the resistance to a crushing force is immense, ninety tons having been sustained without injury.
The final process in brick-making is that of burning the bricks in a kiln or in clamps, the former being the old and the best plan. The kiln may be a simple rectangular chamber, built of old bricks and rubble stone, with a narrow doorway at each end, and narrow fire-holes lined with fire-bricks in the side walls exactly opposite each other. The workmen introduce through the doorways a quantity of bricks, and stack them loosely but with considerable art in cross courses, within the walls, leaving openings that shall act as flues throughout the whole mass, and thus distribute the heat from top to bottom. When the kiln is filled, the top is covered in, and fires are lighted in the fire-holes. The fire is at first got up gently, that the moisture in the bricks may be gradually evaporated; hut in two or three days, when the steam ceases to rise, the heat is raised, the doorways are bricked up, and the temperature continued till the fire begins to appear at the top. It is then slackened, and the kiln allowed to cool- The heating and cooling are then repeated, and in about 48 hours the bricks are thoroughly burnt. An ordinary kiln will hold 20,000 bricks. The fuel consists in some places of fagots of furze, heath, brake, &c., in others of pit coals. When bricks are burnt in a clamp, they afford to a great extent their own fuel, for a clamp is an immense pile of carefully arranged bricks, in which breeze, (the technical name for ashes,) has been mixed with the clay in their manufacture. But layers of breeze are also added, and the whole is set fire to by means of fireplaces and flues filled with wood, coal, and breeze. The burning of a clamp continues from two to six weeks. The art of clamping well exhibits no mean degree of skill in the workman. They first build an upright or double battering wall along the centre, and then arrange a number of other walls in an inclined position on each side, corresponding in length and height with the central wall, and supported by it. The sides and top of the clamp are cased with burnt brick, and the lower courses of the central double wall are of the same material. There are numerous live-holes left in a large clamp, and these are fired in succession. The bricks near these live-holes are burnt too much, and generally spoiled by running together in masses called burrs, and the bricks at the outside of the clamp are not burnt enough, and are laid aside for reburning in the next clamp. Much judgment is required in apportioning the fuel to the size of the clamp, for the whole may be easily underburned or ovcrburned, and so deteriorated or rendered comparatively useless. The burrs and clinkers, or shapeless masses of fused brick, may often be recognised in the rock-work of suburban gardens, while the pale underbaked bricks, sold at low price, are used in the inferior unsubstantial erections which disgrace the neighbourhood of the metropolis.
The processes above described are not universally prevalent. On the contrary, various differences exist in particular districts. These are well indicated in the following paragraph from Dobson's clever Treatise on "Brick and Tile-making."' "In some districts the clay is ground between rollers, aud the pug-mill is never used. In others both rollers and pug-mills are employed. In the neighbourhood of London rollers are unknown, and the clay is passed through a wash-mill. Equal differences exist in the processes of moulding and drying. Lastly, the form of the kiln varies greatly. In many places the common Dutch kiln is the one employed. In Essex and Suffolk the kilns have arehed furnaces beneath their
tl) Wealc's Rudimentary Series.
floors. In Staffordshire, bricks are fired in circular domed ovens called cupolas."
At the close of the last century, bricks were for the first time subjected to taxation. A duty of 2*. 6</. per thousand was imposed on all bricks, and tiiis was afterwards raised to 4*. per thousand. Subsequently, bricks were divided into common and dressed, and separate duties were laid upon each. In 1833, the duties on tiles were wholly repealed, but those on bricks still remained, and were raised two years later, so that common bricks paid 5*. lOrf. per thousand, and superior ones a higher rate. In 1839, the duty of 5*. lOd. was made general on all bricks, without distinction of shape or quality, and this was felt as a boon, because the restrictions had previously limited the manufacture of various patterns. It was also enacted that bricks used in draining marshy land should be exempt from duty, provided the word "Drain" was legibly stamped upon them. Bricks made in Ireland, and also bricks for exportation, were never subjected to duty, but with respect to the latter, sufficient security was required before shipment that they should not be re-landed in England, and if it was discovered that this was done, the owner had to suffer, over and above the penalty in his bond, the forfeiture of the whole cargo. By a recent act, the duty on bricks was wholly repealed. Notwithstanding the influence of the duty, the number of bricks made in England has nearly doubled during the twenty years ending with 1840, the number that paid duty in 1821 having been 899,178,510, whereas in 1840, it amounted to 1,677,811,134; and the latest accounts make it nearly 1,800,000,000, which produced an annual revenue approaching 600,000/. The manufacture of bricks in Scotland is much less important than in England, owing to the extensive use of stone as a building material in that countrv.
BRICKLAYING is the art of building with"bricks, or of uniting them by cement or mortar into various forms. Bricks of English make are commonly of one form, 9 inches long, 4J broad, and 2J deep. They vary greatly in quality, according to the quality of the material, the manner in which the clay is tempered, and the method of burning.
The bricklayer, who is always assisted by a labourer, to supply him with bricks, mortar, &c., executes his work by the aid of a few simple tools. These are:—1. A brick-trowel, Fig. 241.
made of well- _. ___ fD\
cutting holes .
and chases in 1 1 J'
twelve feet long, with a vertical rule attached to it, in which a line and plummet are suspended: its use is to try the level of the walls at various stages of the building, as it proceeds, and particularly at the window-sills and wall-plates; 5. The large square, for setting out the sides of a building at right angles; 6. The rod, for measuring lengths, usually five or ten feet long; 7. The jointing rule, about eight or ten feet long, and four inches broad, with which the bricklayers run, or mark, the centre of each joint cf the brickwork; 8. The jointer, Fig. 243, an iron tool, shaped like the letter S: it is used with the jointing-rule for marking the joints; 9. The
compasses, for traversing arehes and vaults; 10. Tlte raker, Fig. 244, a piece of iron, having two knees, or angles, the points of which are used for raking out decayed mortar from the joints of old walls, for the purpose of replacing it with new mortar, or, as it is called, pointing them; 11. The hod, a wooden trough, shut close across at one end, and open at the other: the sides consist of two boards at right angles to each other, with a long handle projecting downwards from the middle of the angular ridge formed by the meeting of the two sides; this ridge is also partly covered by a cushion of leather, stuffed with wool, to prevent it from cutting the shoulder of the labourer. The hod is used by the labourer for conveying bricks and mortar to the bricklayer. To prevent the mortar from sticking, dry sand is strewed on the inside; 12. The line-pins. Fig. 245, which are of iron, for fastening and stretching the line at proper intervals of the wall, that each course may be kept straight in the face and level on the bed: the pins have a line attached to them, of sixty feet to each pin; 13. The rammer, similar to that of paviours: it is used for trying the
of wood about half an inch thick, with at least one curved edge, rising about one inch in six feet, for drawing the soffit line of straight arehes. When the lower edge is curved, it rises about half that of the other, or about half an inch in six feet, for the purpose of drawing the upper lino of the areh, so as to prevent it becoming hollow by the settling of the areh. The upper edge is not always cambered, some preferring it straight. The slip being sufficiently long, it answers the width of many openings; and when the bricklayer has drawn his areh, he delivers it to the carpenter, to prepare the centre for it; 17. The rubbing-stone is a rough-grained stone, about twenty inches diameter, or less. It is fixed upon one end of the banker, Fig. 246, upon a bed of mortar. After the bricks for the gauged work have beeu rough-shaped by the axe, they are rubbed smooth on the rubbingstone. The headers and stretehers, in return, which are not axed, are called rubbed returns, and rubbed headers and stretchers; 18. The bedding-stone, a straight piece of marble, eighteen or twenty inches long, of any thickness, and about eight or ten inches wide. Its use is to try the rubbed side of a brick, which must be first squared, to prove whether its surface be straight, so as to fit it upon the leading skew back or leading end of the areh; 19. The square, for trying the bedding of the bricks, and squaring the soffits across the breadth of the bricks; 20. The bevel, Fig. 218, for drawing the soffit line Fis 2<son the face of the bricks; 21. The mould, for forming the face and back of the brick, in order to reduce it in thickness to its proper taper, oue edge of the mould being brought close to the bed of the brick when squared. The mould has a notch for every course of the areh; 22. The scribe, a spike or large nail, ground to a sharp point, to mark the bricks on the face and back by the tapering edges of the mould, for the purpose of cutting them; 23. The tin saw used for cutting the soffit lines about