Mortar

Mortar. 1. A piece of heavy artillery, shorter than a howitzer, designed for throwing shells at high angles, and especially useful for the purpose of bombarding a town or fortress. Mortars of as much as 13 inches calibre were employed in the 18th century in the navy, and were generally mounted on platforms in bomb-vessels. They fired spherical shells weighing 195 lbs., with a bursting charge of 7 lbs. of powder. Mortars somewhat longer than thoseof the ancient pattern are now rifled and breech-loading, and the dividing line between them and howitzers is scarcely maintained. 2. A cement formed by a mixture of lime, sand, and water, which is used for cementing the stones, bricks, etc., in building, and for plastering walls, etc. On drying it sets, and in time becomes as hard as, or harder than, the cemented stones, with the formation of calcium carbonate from the lime. If silica is present to the extent of about 12 per cent. the mortar possesses the power of setting under water, and is known as hydraulic cement.