BRICKS, among us, are various, according to their various forms, dimensions, uses, method of making, &c. the principal of which are, Compas-bricks, of a circular form, used in laying of walls: Concave, or hollow bricks, on one side flat like a common brick, on the other hollowed, and used for conveyance of water: Feather-edged bricks, which are like common statute bricks, only thinner on one edge than the other, and used for penning up the brick pannels in timber buildings: Cogging bricks are used for making the indented works under the capping of walls built with great bricks: Capping-bricks, formed on purpose for capping of walls: Dutch or Flemish bricks, used to pave yards, stables, and for soap-boilers vaults and cisterns: Clinkers, such bricks as are glazed by the heat of the fire in making: Sandel or samel-bricks, are such as lie outmost in a kiln, or clamp, and consequently are soft and useless, as not being thoroughly burnt: Great bricks are those twelve inches long, six broad, and three thick, used to build fence-walls: Plaster or buttress bricks, have a notch at one end, half the breadth of the brick; their use is to bind the work which is built of great bricks: Statute-bricks or small common bricks, ought, when burnt, to be nine inches long, four and a quarter broad, and two and a half thick; they are commonly used in paving cellars, sinks, hearths, &c.
Bricks are burnt either in a kiln or clamp. Those that are burnt in a kiln, are first set or placed in it, and then the kiln being covered with pieces of bricks, they put in some wood to dry them with a gentle fire; and this they continue till the bricks are pretty dry, which is known by the smoke's turning from a darkish colour to a transparent smoke: They then leave off putting in wood, and proceed to make ready for burning, which is performed by putting in bruth, furze, spray, heath, brake, or fern-faggots; but before they put in any faggots, they dam up the mouth or mouths of the kiln with pieces of bricks (which they call shin-log) piled up one upon another, and close it up with wet brick-earth, instead of mortar.
The shin-log they make so high, that there is but just room above it to thrust in a faggot; then they proceed to put in more faggots, till the kiln and its arches look white, and the fire appears at the top of the kiln; upon which they slacken the fire for an hour, and let all cool by degrees. This they continue to do, alternately heating and slacking, till the ware be thoroughly burnt, which is usually effected in forty-eight hours.
About London they chiefly burn in clamps, built of the bricks themselves, after the manner of arches in kilns, with a vacancy between each brick, for the fire to play through; but with this difference, that instead of arching, they span it over by making the bricks project one over another on both sides of the place, for the wood and coals to lie in till they meet, and are bounded by the bricks at the top, which close all up.
The place for the fuel is carried up strait on both sides, till about three feet high; then they almost fill it with wood, and over that lay a covering of sea-coal, and then overspan the arch; but they strew sea-coal also over the clamp, betwixt all the rows of bricks; lastly, they kindle the wood, which gives fire to the coal; and when all is burnt, then they conclude the bricks are sufficiently burnt.