In the year 1853 a Company was formed at Paris for producing (by the aid of some large magneto-electric machines) gas for combustion, by the decomposition of water. The Company failed to produce gas, and what was perhaps more to the annoyance of the subscribers, they failed also to shew any dividends, and the expensive machines were voted impostors. However, an Englishman, Mr Holms, succeeded in turning them to better account, and eventually produced by their aid a light of great power. Mr Wilde of Manchester was another worker in the same field; and improved machines were soon introduced to public notice by both gentlemen. A few years after, the South Foreland and Dungeness lighthouses were provided with experimental lights. (The first-named headland had previously been furnished with an oxyhydrogen or lime light, a source of illumination which is also open to the same objections of requiring constant attention and renewal.)
It is a matter of surprise to most visitors to the South Foreland lighthouse to find that a small factory and staff of men are necessary to keep the electric apparatus in working order. The extent of the establishment is partly explained by the fact that, in case of a breakdown of any part of the apparatus, everything is kept in duplicate. Hence there are two ten horse-power steam-engines, and a double set of magneto-electric machines, although only half that number are in actual use at one time. The old oil-lamps are also kept ready, in view of the improbable event of both sets of electrical apparatus going wrong.
Although lighthouses were the first places to which electrical illumination was applied, there are many other purposes for which that species of light is invaluable. One of the chief of these is its use in submarine operations. Unlike other lights, being quite independent of atmospheric air or any kind of gas for its support, and merely requiring an attachment of a couple of gutta-percha-covered wires for its connection with the source of electricity (which may be at a considerable distance from the place of combustion), it is specially applicable to the use of divers. The importance of a means of brilliantly lighting the work of those engaged in clearing wreck or laying the foundations of subaqueous structures cannot be over-estimated. There is another service too in which we may hope some day to see it commonly employed: we mean as a source of light to our miners. For this purpose, the burner could be placed in a thick glass globe hermetically closed; in fact the globe might even be exhausted of air, for experiments prove that the light is in several respects improved when burnt in a vacuum! The danger of fire-damp explosion would by this means be almost altogether obviated; for unless the glass were broken (and abundant means suggest themselves for protecting it), no communication could be made between the light and the gas-laden air of the mine. As a means of night-signalling, the electric light can also be profitably applied. This can be done by an alphabet of flashes of varying duration; the readiness with which the light can be extinguished and rekindled by the mere touch of a wire, rendering it peculiarly adapted for such a purpose; while the distance at which it can be seen is perhaps only limited by the convexity of the earth. Several of Her Majesty's ships are now being fitted with the electric light, which is to serve both for signalling purposes, and as a precautionary measure against the attack of torpedo-boats. For military field operations a brilliant light is often useful; and an electrical apparatus is in actual use by one of the belligerents in the present war. In this case, the light is doubtless worked by an electric battery, as a steam-engine is hardly a convenient addition to the impedimenta of a moving column.