(Βόμβας, a loud noise), in military affairs, a large shell of cast-iron, with a vent to receive a fusee, which is made of wood. The shell being filled with gunpowder, the fusee is driven into the vent within an inch of the head, and fastened with a cement made of quicklime, ashes, brick-dust, and steel-filings, worked together in a glutinous water; or of four parts of pitch, two of colophony, one of turpentine, and one of wax. This tube is filled with a combustible matter made of two ounces of nitre, one of sulphur, and three of gunpowder-dust, well rammed. To preserve the fusee, it is pitched over, but uncased when the bomb is put into the mortar, and covered with gunpowder-dust, which, taking fire by the flash of the powder in the chamber of the mortar, burns all the time the bomb is in the air; and when the composition in the fusee is spent, it fires the powder in the bomb, which bursts with great violence and commits dreadful devastation.

Bombs may be used without mortars, as was done by the Venetians at Candia, when the Turks had possessed themselves of the ditch. Bombs were rolled down upon them along a plank with ledges set sloping towards their works. Bombs did not come into common use before the year 1634, and then only in the Dutch and Spanish armies. One Malthus, an English engineer, is said to have first carried them into France, where they were used at the siege of Collioure. The art of throwing bombs or shells constitutes a branch of gunnery. See GUNNERY.

BOMB-VESSEL, or Bomb-Ketch, a small ship of unusual strength, employed for throwing bombs into a fortress; said to have been invented by M. Reynaud, and first used at the bombardment of Algiers. Till then it had been judged impracticable to bombard a place from the sea.