Mortar
or MORTER, a vessel, generally in the form of a bell or conical frustrum, in which substances are pounded by a pestle. When large, they are made of cast-iron; a smaller size is made of bronze, and those for more delicate pharmaceutical operations are of marble, pottery, porphyry, or agate. They are used in connection with a pestle, which in the larger mortars is of iron, and in the smaller is of porcelain or agate. Also a calcareous cement. Hydraulic mortar is made from certain limestones which include in their composition so large a proportion of iron MORTIFICATION and clay as to enable them to form cements which have the property of hardening under water, and are called hydraulic limestones.
Short pieces of ordnance used to force shells at high angles, generally 45°, the charge varying with the range required.
They are distinguished by the diameter of the bore, such as 13-inch, 10-inch, and 8-inch, which are commonest, forms of smooth-bore mortars. They are made of cast iron or bronze; but rifled mortars, resembling short howitzers, are wrought iron or steel. The bronze mortars are usually of small caliber. of MORTE D'ARTHUR (môrt där'thur), a famous compilation of romances relating to the life and death of King Arthur and the knights of the Round Table, made by Sir Thomas Malory and printed by Caxton (1485). It is in prose, and was translated from the French prose romances. See MALORY, THOMAS.