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Electric Lighting

The last quarter of the 19th Century witnessed notable advances in the development of electric lighting, the most important pioneers being Edison, Swan and Lane Fox. In 1879 Edison succeeded in making a successful lamp in an evacuated glass bulb; this contained a carbonized filament, into which the current was passed through fine platinum wires. It was first shown commercially in London in 1882. Many different types of lamps have followed this beginning, although lamps operating on Davy's carbon arc principle of nearly a century earlier were still used in London and elsewhere until well in the 20th Century. The passage of a current through neon, sodium and other gases, without a filament, is a comparatively modern development and now provides brilliant street lighting and illuminated signs, and is beginning to be used for household as well as office and factory lighting.

An important part of the ordinary electric bulb, the lamp-holder, is nearly always stamped out of brass. So suitable is this alloy for this purpose that when, owing to a temporary shortage of brass a few years ago, another material was used, the manufacturers reverted to brass as soon as possible, although the alternative was cheaper. Plastics have made considerable advances during recent years for non-conducting components. This has also been the case with small household switches; but brass contacts, screws and other parts are still of course essential.