Arc Lamp

—A device for producing light by the voltaic arc. An automatic mechanism operated by both mechanical and electrical means, is used to regulate carbon electrodes, so that they touch when no current is flowing and spring apart when the current is turned on. Arc are divided into several cla es; as, (a) having fixed parallel carbons; (b) lamps without regulating mechanism; (c) lamps in which the whole current pa es through the regulating mechanism; (d) lamps having the regulating mechanism and the carbons with their are in parallel. Recent improvements have been made in arc lamps in which the arc itself has been made luminous, which have become known as “flaming are. lamps,” while comparatively little light comes from the hot carbon tips, with an increased efficiency, nearly ten times as great with the standard carbon are lamps. y