Shell
Shell, a hollow projectile within which is placed a bursting-charge of gunpowder or other explosive material, furnished with a fuse to ignite it at the moment desired. Shells are said to have been first employed by the Sultan of Gujerat in the latter part of the 15th century. They are commonly made of cast-iron or steel. The original type, which survives in the common shell, was spherical, being fired from a mortar or smooth-bore cannon, and was invariably filled with powder. Shrapnel shells, invented by Colonel Henry Shrapnel, R.A. (d. 1842), are filled with bullets and a small bursting-charge of sufficient power to split the shell without impeding the flight of the bullets, which then spread over a wide area, their speed remaining unaltered. The Shrapnel shell, being now used for rifle gnns, is elongated in form. Palliser shells have sharp-pointed heads which are almost solid, and become chilled by being cast in iron moulds, the result being that their hardness enables them to pierce ships' armour to a very great depth; the explosion takes place without the use of fuses.