Safety lamp

Safety lamp, Davy, plano-convex lens, maker: J. Newman, London, marking: makers name, 1827-56

This is one of the simplest forms of the miner's safety lamp. The gauze is of black iron with 28 wires to the linear inch and is set in a brass ring by which it can be screwed on to the small oil lamp. The top of the gauze is formed with a sliding cap so that there are two thicknesses of gauze where the wear is most severe. The oil reservoir can be filled through an external hole and the wick can be trimmed, without opening the lamp, by a wire that passes in a pipe through the reservoir. A modified form is also shown, in which the light can be concentrated by a lens carried in a frame that slides on the cage.