in a general sense, any glutinous substance, capable of uniting and keeping things together in close cohesion: in this sense, under cement, are comprehended mortar, solder, glue, &c. But, strictly speaking, the term cement only denotes a glutinous composition, used in cementing broken glasses, china-ware, or earthen-ware.

One of the finest, and at the same time strongest cement for this purpose, is the juice of garlic stamped in a stone mortar: this, if the operation is done with care, leaves little or no mark. Another cement is made by beating the white of an egg very clear, and mixing with it fine powdered quick-lime: or using glass, powdered chalk, and a little lime may be mixed together, and dissolved in fair water. With these, the glasses, &c., are to be cemented, and then set in the shade to dry; a caution which should always be observed, whichever of the above cements is used.

A cement for cracked chemical-glasses, that will stand the fire, may be thus prepared: take wheat flour, fine powdered Venice glas, and pulverized chalk, or each an equal quantity; of fine brick-dust, one half of the said quantity; and a little scraped lint: mix them all together with the whites of eggs; then, spreading this mixture upon a linen cloth, apply it to the cracks of the glasses, which must be well dried before they are used. Old varnish is another cement that will answer the same purpose.

Cement, among builders, a strong sort of mortar, used to bind bricks or stones together for some kind of mouldings; or in cementing a block of bricks for the carving of capitals, scrolls, or the like. There are two sorts, 1. Hot cement, which is the most common, made of resin, bees-wax, brick-dust, and chalk, boiled together. The bricks to be cemented with this kind, must be made hot with the fire, and rubbed to and fro after the cement is spread, in the same manner as joiners do when they glue two boards together. 2. Cold cement, made of Cheshire-cheese, milk, quicklime, and whites of eggs. This cement is less used than the former, and is accounted a secret known but to few bricklayers.

Cement, among engravers, jewellers, &c., a composition of fine brick-dust well sifted, resin, and bees-wax, in use among these artificers to keep the metals to be engraved or wrought on firm to the block; and also to fill up what is to be chiseled.

Cement, in chemistry, a kind of menstruum compound of salts, sulphurs, and brick, reduced to dry powders, and stewed betwixt plates of metal, in order to raise their colour, or separate one metal from another. See Chemistry.

Cement-pots, or those used in the cementation of metals, are made of fine potter's clay, and that either pure, or mixed with sand in different proportions.

Cementation, in a general sense, the corroding of metals in a dry form, by means of the fumes of acid salts. See Chemistry, Part II.