A safety lamp designed for use in potentially hazardous atmospheres such as firedamp and coal dust, the lamp is mounted on the front of the miner's helmet and powered by a wet cell battery worn on the miner's belt. The average wheat lamp uses a three to five watt bulb which will typically operate for five to 16 hours depending on the amp-hour capacity of the battery and the current draw of the bulb being used.L. C. Isley, A. B. Hooker, Permissible Electric Mine Lamps, US Department of Commerce Bulletin No. 332, 1930, pp. 32-34
