MORTAR. A type or form of ordnance used for high-angle fire. In design it is short in length in proportion to its calibre or size of bore. In the United States and England mortars are almost entirely used for coast defense purposes. In the former country mortar batteries consist of either eight. or sixteen mortars each, four mortars to a pit. The pits are fortified with parapets constructed of sand reenforced on the interior by a concrete wall. They are separated by sub stantial traverses which contain the necessary magazines, bomb-proofs, etc. (See illustration under FounFicATIoN.) The batteries are con trolled by an officer (the predicting officer), who observes the plotting board, the target, and the effect or destination of the projectile, in order to give the proper direction and elevation to the men working the pieces in the pit. France has taken the lead in the manufacture of these types of ordnance, the Creusot works of Messrs. Schneider & Co. being perhaps the best known in the world.
The use of field mortars has not been as yet put to the test of modern battle conditions, so that their employment is largely a matter of conjecture. In 1903 Russia led the world with
a regularly organized and equipped division of 24 batteries, 6 mortars to a battery. Austria and Germany come next, the latter country dif fering. from Russia in details of organization. Although the advantages of field mortars are conceded to be greater than their disadvantages, the latter are still sufficiently important to delay their general immediate employment. The most important disadvantage is the difficulty of getting men so thoroughly trained that they are equally expert with the ordinary fiat projector field gun and the high-angle mortars. Another defect in field mortars is their utter inability of de fending themselves at close range. For illus tration of the 12-inch breech-loading mortar used in the United States service. see COAST ARTILLERY, and for an illustratiOn of the 10-inch cast-iron muzzle-loading mortar, see ARTILLERY. See also COAST DEFENSE HOWITZER ; ORDNANCE. Under the latter head the construction of a mod ern mortar is described.