Sir Humphry Davy invented the carbon arc lamp in 1802 upon discovering that electricity could produce a lightarc with carbon electrodes. However, it was not used to any great extent until a practical means of generating electricity was developed.
Carbon arc lamps were started by making contact between two carbon electrodes, which were then separated to within a narrow gap. Because the carbon burned away, the gap had to be constantly readjusted. Several mechanisms were developed to regulate the arc. A common approach was to feed a carbon electrode by gravity and maintain the gap with a pair of electromagnets, one of which retracted the upper carbon after the arc was started and the second controlled a brake on the gravity feed.[6]
Arc lamps of the time had very intense light output (in the 4000 candlepower range), released a lot of heat, and they were a fire hazard, all of which made them inappropriate for lighting homes.[7]
In the 1850s, many of these problems were solved by the arc lamp invented by William Petrie and William Staite. The lamp used a magneto-electric generator and had a self-regulating mechanism to control the gap between the two carbon rods. Their light was used to light up the National Gallery in London and was a great novelty at the time. These arc lamps and designs similar to it, powered by large magnetos, were first installed on English lighthouses in the mid 1850s, but the power limitations prevented these models from being a proper success.[8]
The first successful arc lamp was developed by Russian engineer Pavel Yablochkov, and used the Gramme generator. Its advantage lay in the fact that it didn't require the use of a mechanical regulator like its predecessors. It was first exhibited at the Paris Exposition of 1878 and was heavily promoted by Gramme.[9] The arc light was installed along the half mile length of Avenue de l'Opéra, Place du Theatre Francais and around the Place de l'Opéra in 1878.[10]
British engineer R. E. B. Crompton developed a more sophisticated design in 1878 which gave a much brighter and steadier light than the Yablochkov candle In 1878, he formed Crompton & Co. and began to manufacture, sell and install the Crompton lamp. His concern was one of the first electrical engineering firms in the world.
Incandescent light bulbs[edit]
Various forms of incandescent light bulbs had numerous inventors; however, the most successful early bulbs were those that used a carbon filament sealed in a high vacuum. These were invented by Joseph Swan in 1878 in Britain and by Thomas Edison in 1879 in the US. Edison’s lamp was more successful than Swan’s because Edison used a thinner filament, giving it higher resistance and thus conducting much less current. Edison began commercial production of carbon filament bulbs in 1880. Swan's light began commercial production in 1881.[11]
Swan's house, in Low Fell, Gateshead, was the world's first to have working light bulbs installed. The Lit & Phil Library in Newcastle, was the first public room lit by electric light,[12][13] and the Savoy Theatre was the first public building in the world lit entirely by electricity.[14]
