A New Development in Carbon Arc Lighting

A new motion picture arc lamp designed for use as a general lighting unit is described, in which the new 8-mm., copper-coated, cored carbons are used. Two special mechanisms feed the two carbons of the unit independently of each other, the rate of feed of each being controlled by the voltage drop in each arc. Each control circuit includes a voltage coil and a current coil, acting in magnetic opposition, which arrangement avoids variations of light intensity, flickering, and blinking. The lamps operate under a voltage of 115, drawing a current of 40 amperes, d-c.