a preparation of lime and sand mixed with water, which serves as a cement, and is used by masons and bricklayers in building walls of stone and brick.

chemical utensil, very useful for the division of bodies, partly by percussion and partly by grinding. Mortars have usually the form of an inverted bell. The matter intended to be pounded is put into them, and there struck and bruised by a long instrument denominated a pestle. The motion given to the pestle ought to vary according to the nature of the substances to be pounded. Those which are easily broken, or which are apt to fly out of the mortar, or which are hardened by the stroke of the pestle, require that this instrument should be moved circularly, rather by grinding or bruising than by striking. Those substances which are softened by the heat occasioned by rubbing and percussion require to be pounded very slowly. Lastly, those which are very hard, and which are not capable of being softened, are easily pounded by repeated strokes of the pestle; they require no bruising but when they are brought to a certain degree of fineness. But these things are better learned by habit and practice than by any directions.

the military art, is a short cannon of a large bore, with chambers; it is made of brass or iron, and its use is to project hollow shells, filled with powder, called bombs, and sometimes also carcasses. (See Artillery.) The mortars used at sea are fixed in bomb-vessels, which are constructed for their reception; they are made somewhat longer and much heavier than those employed on land. See Gunnery.