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
Safety lamp electric lights. Miners have traditionally referred to the various gases encountered during mining as damps, from the Middle Low German word "dampf" (meaning "vapour"). Damps are variable mixtures and are historic terms. Before the invention of safety lamps, miners used candles with open flames. This gave rise to frequent explosions. For example, at one colliery (Killingworth) in the north east of England, 10 miners were killed in 1806, 12 in 1809. In 1812, 90 men and boys were suffocated or burnt to death in the Felling Pit near Gateshead and 22 in the following year. When they came into regular