Mining safety lamp. 19th-century artwork of the electric lamp invented by Dumas and Benoit in the mid-19th-century. It was developed for use in coal mines, where one of the hazards was igniting the methane gas (fire-damp) that formed there. The use of an electric light avoided the naked flame of an oil lamp, and was superior to the Davy safety lamp (invented in 1815) that still required oxygen to burn. This Ruhmkorff lamp consists of a Geissler tube (with a partial vacuum) containing a gas that glows when an electric current passes through it (supplied from a generator in the case). This was a forerunner of fluorescent tube lights. Artwork published in Mines and Miners (L. Simonin, 1868).