Brick
2 of the 7 encyclopedias on this shelf carry an entry for Brick. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
a well known building material. Bricks are really a kind of coarse, porous, unglazed pottery, made from common clay. Almost any reasonably clean clay answers the purpose. It must be free, however, from limestone pebbles, lest the burning convert them into lime which would later absorb water and slake, causing the brick to chip or split open. Brickmaking is not a complex process. Brick clay, fuel, and water are the essentials. If necessary, the clay is first screened to free it from pebbles. It is then ground, mixed with water, and worked into a plastic, stiff mud in a mill or large wooden barrel in which paddles driven by machinery stir the mass thoroughly. The well kneaded clay is pushed out at the bottom, and is molded or cut into bricks. The largest brick machines turn out 30,000 bricks a day. The green bricks are stacked up under light sheds to harden for a few days. Care must be taken not to let them dry too fast lest they crack. The air-dried bricks are then built up in large kilns properly constructed to allow the flames to race through channels at suitable intervals. Wood or coal and, in some localities, gas, is used for fuel. The firing should be light at first and should increase gradually in intensity. For common brick the heat should reach 1,800 deg. F., and for paving brick the heat should be more intense. The more intense the heat, the more the ingredients, especially sand, which is present in all brick clay, are melted together in a glassy fusion. Fire bricks, in fact, are made of clay containing a large degree of sand and are fired to such a degree of heat that they are afterward virtually fireproof and will neither crack nor warp. They are brittle, however, and in a wall require to be backed by common brick. The red color of some bricks is due usually to the presence of iron. The redder the brick, the more iron. Dark brown brick also owes its color to burnt iron. Yellow and cream colored brick derive their color from lime and iron. An ordinary brick is 2 X 4 X 8 inches. Bricks are manufactured, sold, and laid in walls usually at a price per thousand. A chimney builder plans his dimensions in multiples of four inches, allowance being made for mortar. In addition to the regular size, bricks of a thousand conceivable shapes and sizes may be ordered for special cases. There are about 8,000 manufactories in the United States , turning out, it is estimated, 25,000,000,000 bricks annually. About $2,000,000 worth are exported. The earliest brickmaking of which we have remains was doubtless carried on by the Babylonians and Egyptians in the grain producing valleys of the Euphrates and the Nile, where both timber and stone were lacking. Sun-dried bricks 4,000 years old may be found in a state of excellent preservation. Straw was used to give the bricks greater coherency. For a story of the Egyptian taskmasters who forced the Israelites to gather their own straw from the stubble fields, see Exodus i: 14; v: 4-19. See Adobe ; Clay ; Pottery 2026 Editor's Note: The brick has barely changed, which is its distinction — a fired clay block of a size one hand can lift is among the oldest manufactured objects still made and used the same way. What changed was scale: the continuous Hoffmann kiln , patented in 1858, let a works fire bricks around the clock instead of in batches, and made the brick cities of the industrial age possible. (Ed: BR 2026-07-08)
Collier's New Encyclopedia (1921)
a kind of artificial stone, made of clay, molded, dried in the sun and baked in a kiln. The word is also applied to the block in its previous condition as a molded plastic mass, and as a dried block in which the water hygrometrically combined with the clay is driven off. When this condition is accepted as a finality, the block so dried is an adobe. The burning of the previously dried brick drives off the chemically combined water, and forever changes the character of the mass. An adobe may become resaturated with water, and resume its plasticity; a brick may become rotten and disintegrated, but not plastic. There are two principal kinds of brick, building brick and fire brick, and their composition depends upon the use to which they are put; a good building brick will contain about 50 per cent. silica, 25 per cent. alumina and oxide of iron, 3 per cent. carbonate of lime, 1 per cent. carbonate of magnesium, and 21 per cent. of water and other constituents; while a fire brick will contain about 59 per cent. silica, 35 per cent. alumnia, 3 per cent. of oxide of iron, and only 3 per cent. of carbonate of lime, carbonate of Magnesia, and water, combined. Fire brick is used to line furnaces, crucibles, and in other places where a high heat is maintained; and must contain as little fusible matter as possible. Some of the best clays in the world for brick making are found in New Jersey, at Perth Amboy, Woodbridge, and Trenton, and one of the largest brick making establishments in the world is situated at Haverstraw, N. Y. Building bricks come under various names according to the use to which they are put, or the position they occupy in a building. Some of these are: Air brick is an iron grating the size of a brick, or a perforated brick, let into a wall to allow the passage of air. Arch brick usually means the hard burned, partially vitrified brick from the arches of the brick clamp in which the fire is made and maintained. A brick made voussoir shaped is known as a compass brick. A capping brick is one for the upper course of a wall; clinker, a brick the clamp, so named from an arch of from the sharp, glassy sound when struck; a coping brick, one for a coping course on a wall; feather edged for a great massacre of the Danes. It brick, brick, of prismatic form, for arches, vaults, niches, etc.; fire brick, made of intractable material, so as to resist and kilns; hollow fusion in furnaces brick, with openings for ventilation; given to the best class stocks, a name of bricks, and also locally to peculiar varieties, as gray stocks, red stocks, etc.; pressed brick another name for