Arc lamp Arc lamp An arc lamp or arc light is a lamp that produces light by an electric arc (also called a voltaic arc). The carbon arc light, which consists of an arc between carbon electrodes in air, invented by Humphry Davy in the first decade of the 1800s, was the first practical electric light. It was widely used starting in the 1870s for street and large building lighting until it was superseded by the incandescent light in the early 20th century. It continued in use in more specialized applications where a high intensity point light source was needed, such as
Safety lamp of the safety lamp. The miner was expected to return to the shaft to perform relighting, a round trip of up to a few miles. For men on piece work, this meant a loss of income (perhaps 10% of their day's pay) and so was unpopular. From the mid-century onwards, and particularly after the 1872 act, lamps had to have a lock mechanism which prevented the miner opening the lamp. Two schemes existed; either a special tool was required which kept at the pit head or else opening the lamp extinguished the flame. The latter mechanism can be seen in