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 It was widely used starting in the 1870s for street and large building lighting until it was superseded by the incandescent light in the early 20th century.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
Christopher Miner Spencer Christopher Miner Spencer Christopher Miner Spencer (June 20, 1833 – January 14, 1922) was an American inventor, from Manchester, Connecticut, who invented the Spencer repeating rifle, one of the earliest models of lever-action rifle, a steam powered "horseless carriage", and several other inventions. He developed the first fully automatic turret lathe, which in its small- to medium-sized form is also known as a screw machine. Spencer worked for Samuel Colt’s factory, where he learned the arms-making trade. Although the Spencer rifle had been developed as early as 1859, it was not initially used by the Union. On August 18, 1863,