GRENADE, gre-nricl', a' small hollow ball, cylinder, or cube, of metal, glass, or paper, about two and one-half inches in diameter, which is filled with some explosive, and burst by means of a fuse when it falls among the enemy. Until about the end of the 17th cen tury trained soldiers called grenadiers threw grenades by the hand. Grenades have been de livered from mortars, to repel the close attacks of besiegers sheltering themselves under the besieged walls. This is in anticipation of the modern trench-mortar. They have been found useful also in repelling boat attacks. Grenades were one of the earliest forms of explosive projectiles.
Grenades have again come into military use in the 20th century. Crude bombs made on the spot were employed in the Russo-Japanese War and during the first months of the Great War. A popular form consisted of a jam tin filled with broken iron, with a stick of tri-nitro toluol in the middle, set off by a fuse. Another much used form was the "hair-brush? in which the explosive and iron were bound to a board not unlike the back of a brush, in order to obtain greater convenience in throwing. These were soon superseded by more elaborate devices, among which the best known is the Mills bomb. This consists of an oval casing,
deeply scored to secure better fragmentation, filled with high explosive, and set off by a detonator five seconds after the handle grasped in the palm of the hand is released. This handle is safely secured by a fastening until immediately before the bomb is thrown. Gren adiers form perhaps the most numerous single class of soldiers in a modern company of in fantry.
For ranges greater than those which can be reached by a hand grenade, a rifle grenade is employed. This fastens on an ordinary rifle barrel, and is cylindrical in shape, being scored in a manner like that of a hand grenade. It is projected either by the explosion of a blank cartridge, or by the blast from the muzzle of a gun firing an ordinary ball cartridge. Hand grenades are in use at the present time as fire extinguishers, chemicals being used to fill hol low glass balls, which are thrown into a burn ing mass. Many hotels, hospitals and public bwldings are equipped with hand-grenades.