DAVY LAMP. If a piece of metal gauze is interposed be tween a flame and an explosive gaseous mixture, the heat of the flame is absorbed and conducted away by the metal gauze so that the gaseous mixture does not explode. That is the principle of the Davy lamp, which was invented by Sir Humphry Davy in 1816. The Davy lamp consisted of a small cylindrical oil lamp, covered with a cylinder of wire gauze about 6in. long and 'lin. in diameter, with a flat gauze top. The upper part of the gauze was doubled to prevent it from being worn into holes by the products of combustion. The gauze was mounted in a frame of upright wires screwed into a brass ring at each end. The upper ring carried the handle, and the lower one was screwed to a collar on the oil vessel at the bottom of the lamp. Thus encircled with a case of metal gauze, the flame or gases could not pass out at a temperature high enough to fire an explosive mixture in the mine. For the subsequent developments of this invention, see SAFETY LAMP.