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
SALt lamp SALt lamp A SALt lamp is an LED lamp powered by the galvanic reaction of an anode with saline water. It also has a USB port to charge low-power mobile devices such as cellphones, smartphones, and mp3 players. The anode must be replaced approximately every six months and the saline water daily; sea water is usable. The SALt lamp was invented and is marketed by Aisa Mijeno, a Filipino inventor and entrepreneur. She is also a faculty member of Engineering at De La Salle University — Lipa, and a member of Greenpeace Philippines. The product concept was formed after living