Monday, June 2, 2008

Lighting Device

Lighting or artificial illumination, as opposed to the natural illumination of the Sun or Moon was probably first furnished by campfires and by torches made of dried rushes or resinous wood. Crude stone lamps, in which light came from a flaming wick lying in a pool of oil or melting grease, were used by prehistoric peoples. Candles and oil-burning Lamps remained the chief source of artificial illumination until the middle of 19th century, when kerosene lamps with flat, woven wicks and glass chimneys came into common use.

Gas for Lighting

Illuminating gas was produce first as the by-product of coal distillation in the production of tar. Its potential as an illuminant was recognized as early as the 1970s by the English engineer, William Murdock, and even earlier by a Frenchman, Philippe Lebon (1767-1804). In 1806-16, Murdock installed 1,000 gas lights in a Manchester cotton mill. The first gas generating station, the London Gas Light and Coke Company, was chartered in 1812, and by 1815, London possessed 42 km (26 mil) of gas line that supplied illuminant for street lamps and for a few homes. The first gas burners were simple iron or brass pipes with perforated tips, or orifices. Later, soapstone mantle in the 1890s greatly increased the brightness of the gas flame.

Electric Arc Lamps
Electric arc lamps consisting of electric arcs drawn between two carbon electrodes were one of the earliest lighting devices to make use of electrical energy. Invented around 1801, arc lamps were not used commercially until 1858, after one had been successfully installed in a Lighthouse in England.