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 is both a source of light and a sensor. A development of the Geordie lamp was the Purdy. A galley with gauze provided the inlet, above the glass was a chimney with perforated copper cap and gauze outer. A brass tube protected the upper works, shielded them and kept them locked in position. A sprung pin locked the whole together. The pin could only be released by applying a vacuum to a captive hollow screw; not something that a nicotine starved miner could do at the coal face. Clanny abandoned his pumps and candles and developed a safety lamp which