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FUZE

727

FUZE

common time-fuze, through one powder-channel. A section of the percussion-fuze is shown in Fig. 2. It is a hollow, gun-metal cylinder (a) so arranged as to screw into the head of the shell. Inside is a movable pellet or ring (b) of white metal, driven with fuze-composition like a tube and carrying a percussion-cap. It has four feathers or shoulders projecting from its sides, and above these a gun-metal guard (c) fits round the pellet loosely, so as to prevent the cap of the pellet from coming in contact with a steel pin which projects downward from the top of the fuze. A safety pin

(d) goes through the fuze with the same object, but is removed before firing, _nd a lead pellet (e) then closes the aperture left by its removal. On discharge, the shock of impact on the target or ground causes the pellet to set forward, bringing the cap against the pin, igniting the fuze composition and bursting the shell. Percussion-fuzes are used chiefly with " common" shell. Very many others are in use, chiefly modifications of these two types: e. g., the delay-action fuze has both a percussion and time arrangement, so as to burst the shell an instant after impact. All are delicate and apt to become hopelessly impaired with age or exposure to damp. In the American pneumatic dynamite-gun, the shell contains an electric battery, and the circuit is completed by the shell striking either water or the target.

FIG. 2