Denton, Greater Manchester and then abandoned. After hatting, the most important industry in Denton was the manufacture of lead-acid batteries by Oldham Batteries (Oldham & Son Ltd). In 1865, Joseph Oldham established a millwright general engineering shop and by 1887 this company was manufacturing machinery for the hat-making industry. Another important industry in the area was coal mining and shortly after 1887 the company began making machinery and equipment for this industry, which included miners' portable lamps. Up to this time, miners had always used the safety lamp devised in 1815 by Sir Humphry Davy (1778–1829) but this new battery-powered Davy lamp eventually
Wheat lamp Wheat lamp A wheat lamp is a type of incandescent light designed for use in underground mining, named for inventor Grant Wheat and manufactured by Koehler Lighting Products in Wilkes-Barre, Pennsylvania, United States, a region known for extensive mining activity. 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 3-5 watt bulb which will typically operate for 5 to 16 hours depending on the