BRICK, an artificial kind of stone, composed in general of earth and sand, or coal cinders. or ashes, well mixed toge ther, and tempered with water. then dried in the sun, and finally burned to a proper degree of hardness in a kiln, or in a heap or stack, denominated a clamp.
The antiquity of bricks seems to be coeval with the first edifices after the Deluge; the tower and city of Babel being built of them ; as also most of the early structures of Egypt. The Greeks chiefly mused three kinds of bricks : the first sort was called Atorapor, bricks of two palms ; the second TrTpad000r. of four pumas; the third Ilevradopoy, /ire palms. Besides these, they also had bricks of just half the above dimensions, used for making their work more solid, and for giving an agreeable diversity to its appearance.
The Romans began to build with brick towards the decline of the republic : according to Pliny, those most in use were a tot and a halt' long, and a foot broad ; which agrees with the dimensions of several Boman bricks found in England, viz. seventeen inches in length, by eleven in breadth. of our measure. Sir floury Walton speaks of sonic bricks at Venice, of which stately columns were built : they were first formed in a circular mould, and cut, prior to their being burned, into four or more sections; afterwards, in laying they were jointed so closely and exactly, that the Ioilla•s had the appearance of being composed of one entire piece.
For the purposes of building, bricks claim a decided superiority over stone, not only as being lighter, and more easily worked; but also because their porous texture fficili tates their union with the mortar, and makes them less liable to attract or retain damp and moisture.
In England, the mould in hich bricks are formed, is ten inches in length, by five in breadth ; the bricks when burned are about nine inches long, four incites and a half broad, and two inches and a half thick. The degree of shrinkage, how (Net., is various, according to the purity and temper of the clay, and the intensity of the heat to which it is exposed in the burning.
The earth selected for brick-making should be of the purest kind ; though indeed bricks may be made of any kind of earth that is free from stones, and even of sea-ooze ; but it is not every soil that will burn red, which is a property peculiar to earths containing ferruginous particles. In this country, bricks are chiefly made either of stiff clay, or of a hazelly-yellowish-coloured fat earth, commonly called loam. The former produces hard red bricks, incapable of rubbing or cutting ; the latter is mostly found near London, and gives a neat gray-coloured brick, which yields freely to the axe and rubbing-stone, though equally durable with the harder red brick made in more distant parts. The earth, of what ever quality, should be dug in the autumn, and suffered to remain in a heap till the next spring, that it may be well penetrated by the air, and particularly by the winter's frosts, which by pulverizing the more tenacious particles, greatly assist the operations of mixing and tempering. Indeed, for the best bricks, two or three years will not be found too long to submit the earth to the action of the atmosphere, in order to render it free in the working. In making up this heap for the season, the soil and ashes or sand are to be laid in alternate layers, or strata ; each stratum containing such a quantity as the stiffness of the soil may admit or require. For making such bricks as will stand the fiercest fires, Sturbridge clay and Windsor loam are esteemed the best.
In tempering the earth, much judgment is required as to the quantity-of sand to be thrown into the mass, for too much renders the bricks heavy and brittle, and too little leaves them liable to shrink and crack in the burnfirg. The London practice of mixing sea-coal ashes, and in the country of adding light sandy earth to the loam, not only makes it work ease and with greater expedition, but tends also to save fuel.