Davy Lamp

Davy Lamp, a device named after Sir Humphry Davy, the inventor, that partially eliminates the danger of introducing a burning candle or oil-lamp into an atmosphere charged with combustible gas. Such an arrangement is desirable in coal mines, where fire-damp is liable to accumulate, and to explode on the introduction of an open burner. Davy's device is to surround the burner with wire gauze, the meshes being sufficiently close to prevent the passage of the flaming gas inside to the combustible gas outside; the gauze is a sufficiently good conductor of heat to prevent much local increase of its intensity, and of course permits the supply of oxygen necessary for combustion of the flame. Recently the electric incandescent lamp has been introduced in place of the old Davy lamp. In this case complete isolation of the white-hot filament is essential for its existence, so it may be entirely screened from the surrounding flammable gas.