in military affairs, a large shell of cast-iron, having a considerable vent to receive the fuse, which is made of wood. The shell being filled with gunpowder, the fuse is driven into the vent or aperture 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 fuse, they pitch it over, but uncase it when the bomb is put into the mortar, and cover it 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 fuse is spent, it fires the powder in the bomb, which bursts with great force, blowing up whatever is about it.

Bombs may be used without mortars, as was done by the Venetians at Candia, when the Turks had possessed themselves of the ditch, rolling down bombs upon them along a plank set sloping towards their works, with ledges on the sides to keep the bomb right forward. Bombs came not 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 makes a branch of gunnery, founded on the theory of projectiles, and the laws and qualities of gunpowder. See Gunnery.

Bomb-Vessels, or small ships formed for throwing bombs into a fortress, are said to have been the invention of M. Reynaeu, and were first used at the bombardment of Algiers. Till then it had been judged impracticable to bombard a place from the sea.