Davy Safety Lamp

( Mining.) A lamp invented by Sir Humphry Davy to obviate the fearful explosions liable to take place in coal-mines from carrying naked lights into places containing fire - damp, a light carburetted hydrogen. This great philosopher found, that, when a lamp is surrounded by wire gauze, the meshes of which were under the 1-40th of an inch, any explosions taking place from the pa age of fire-damp into the lamp, are not communicated to the gaseous mixture outside; in fact, that the heat of the flame pa ing through the wirenet was so much diminished as to be harmle . This may be readily demonstrated by bringing a piece of fine wire-net down on the flame of a candle, when it will be found that the flame will not pa through it. The former reliance upon the safety of the D. lamp, has recently been proven to be a mistake.