BRICK. The ancients used bricks both baked and simply dried in the sun. Those found in the ruins of Babylon [Basyr..ox] are among the oldest specimens existing. The Egyptians used sun-dried bricks, and the pro cess of making them is represented in their paintings. The Greek bricks appear to have been used simply dried. Homan bricks were very thin in proportion to their length and breadth, and were well burnt.
In making ordinary English bricks, the top soil, or eneallow, is first removed from the clay, which is dug and turned over in the winter. Exposure to wet and frost prepares it for use by the spring, when fine ashes are added to it in the proportion of one-fifth ashes to four-fifths clay, or 60 chaldrous to 240 cubic yards, which will make 100,000 bricks. When much sand is mixed with the clay, forming what is called a mild earth, a smaller proportion of ashes may be used. This quan tity requires also the addition of about 15 chaldrons, or, if mild, of about 12 chaldrons of breeze, which is a kind of coarse coal ash, separated by sifting, to aid the burning. The clay and ashes being well mixed by digging, watering, and raking backwards and forwards with a pronged hoe, the mass is removed in barrows to the pay-mill, which consists of an upright barrel in which a series of strong iron knives and teeth are caused to revolve by the power of a horse walking in a circular path, so as to cut and masticate the clay very thoroughly as it passes from the top of the barrel to an aperture provided for its exit at the bottom. As the clay oozes out of the mill, it is removed with a cad/told, or concave shovel, and covered with sacks to prevent it drying too fast. A person called the feedei takes from the stock of clay thus prepared piece about the size of a brick, covers it witl sand, and passes it to the moulder, whc throws it with some force into a wooden mould of the size and shape of the brick which mould is previously sanded. Havin€ filled the mould, the moulder cuts off an3 superfluous clay with a stick kept in a bowl o water by his side, and then removes the bad and sides of the mould, after which the sof brick is carefully transferred from the botton board of the mould to a pallet-board, and, whet a sufficient number have been moulded, is eon veyed with others to the hacks, which an long level lines raised about 4 inches fron the surface of the field, and formed about feet 0 inches wide. The upper surfaces o the bricks are previously sanded, and Brea care is taken to avoid twisting or othenvis injuring their shape in transferring them t the hacks, on which they are laid in two row( with a little space between each to allow th free circulation of air. One double row beM
completed, another is put upon them, an this is continued until the bricks are pile from seven to ten high. In putting thee down the workman counts them, and snakes dot with a stick in every thousandth Mica The hacks are covered with straw at night an showery weather ; and in some brick-field sheds are erected over them ; but this plan i expensive, and retards the drying. Whe partially dried, the bricks are removed, place diagonally, with wider apertures, and with th bottom bricks brought to the top ; and aft( this process, which is called skinning, they ai removed to the kiln or clamp, which is a va. pile of bricks, laid together as closely as pa sible, on a slightly concave foundation of brit rubbish, the raised ends of which face O. north and south. On this foundation the ne bricks are built up in lots or necks, of with the centre one, which is first erected, is verde:. while the others, owing to the concavity of 11 foundation, have a slight inclination towan it. Small spaces, filled with breeze, are le among the lowest courses of bricks, and flue or live-holes, about the width of a brick, ai from 6 to 9 feet apart, are also formed to a the lighting of the clamp, and filled with d bavins or wood. When full, the clamp is su rounded by old bricks, or by the driest those newly made, and a thick layer of bree. is spread on the top. The external bricks a coated with a thin plastering of clay ; and, the weather prove wet, the kiln is protect by loos, or hurdles interwoven with rush( The fire is lighted at the mouths of the flu r live-holes, which are closed when it burns cell ; and in favourable weather the bricks rill be completely burnt in about twenty-five r thirty days, in the course of which time he cindery matter dispersed through their ubstance becomes gradually ignited and con umed. Such bricks as are found to be hn orfectly burnt, are put into the next clamp o be burned again. Those which are suffi iently burnt are separated, according to polity, into—hard sound stocks ; place, or nferior soft red bricks ; and burrs or clinkers, chich are black-looking masses of vitrified >rick, of very inferior value.