The work in electric lighting on board ship for the year 1883 shows how firmly the electric system has become established as the only system for first-class passenger vessels. The report of the Edison & Swan United Companies embraces the work on thirty-one vessels, including three Indian troopships (and four more on order), four vessels for the Clan Line, one for the Peninsular and Oriental Company, one for the Union Steamship Company, three for the Cunard Company, three for the British India Steam Navigation Company, three for the New Zealand Shipping Company, and so on. The list of Messrs Siemens Brothers amounts to twenty high-class vessels, including the _Arizona_, the _Servia_, the _Aurania_, the _City of Rome_, the _City of Chicago_, the _Austral_, the _Germanic_, and the _Massilia_. These two firms thus give fifty-one vessels, and adding those entrusted to outsiders—four in all—affords a total of fifty-five, representing an aggregate of not less than 11,000 incandescent lamps. [Illustration: FIG. 11. EDISON LAMP.] The application of the electric light on board ship to the purposes of signalling, as a substitute for the ordinary system of oil lanterns, has been fully shown in theory and already partially effected in practice, but its development in this direction is necessarily retarded by considerations which do not affect its use in the interior of vessels. Vessels traversing the ocean in darkness are necessarily dependent one on the other for the means of knowing their proximity, and as the electric light much exceeds in power and brilliancy that of oil lanterns, it would have the effect of eclipsing the latter even within a large radius. The adoption of the electric light for this very important purpose would, therefore, have to be pretty much a simultaneous and general movement throughout the ships of the various companies, if not of the various nations. Apart from such considerations, however, other objections have been instanced to the appropriation of the electric light for this purpose. Difficulty, it is said, has been experienced in distinguishing the colours pertaining to the port and starboard side-lights, and fears are entertained regarding the liability of the light, or the machinery employed in generating the current, to suddenly fail in its action. Few of the objections named, of course, amount to very serious obstacles, and as the system is yet so much in its infancy, it may well happen that a few years will witness all that is here foreshadowed.