This is the authentic miner's lamp made by the 148 year-old company E. Thomas & Williams of Aberdare, Wales, improving upon the original miner's safety lamp invented by Irish physician William Reid Clanny in 1813. It was used by colliers during the Industrial Revolution in Wales to detect the presence of "firedamp"--the explosive gasses encountered while mining--and the lack of oxygen. The lamp's internal safety gauzes serve as flame arrestors by regulating the flow of atmosphere; when flammable gases are detected, the lamp's flame changes color, but the mesh prevents the flame from propagating through and igniting any external firedamp. The flame will extinguish when not enough oxygen is present in the ambient atmosphere. The exterior is made of solid brass with a glass cylinder housing the flame. Burns for 20 hours using 3 1/2 oz. of refined kerosene (lamp oil). 10 1/2" H x 3 1/2" Diam. (3 lbs.)