Fuze, Electric

A fuze ignited by the pa age of an electric current. It is used for firing torpedoes, for the simultaneous discharge of guns and charges in mining. The principle used is the heating of the wire by the current at a point of resistance. The point of resistance is called the bridge . Being surrounded by a priming of powder or other explosive, its sudden heating causes ignition in the fuze. The bridge is made in various ways,—by connecting the current wires by a fine platinum wire; by pa ing the current through a chemical mixture rendered conducting by containing a salt of copper; also by filing the main wire nearly in two, and rubbing the cut with a lead-pencil.