ELSEWHERE in this issue will be found a description of the various wireless telephone systems which have been proposed, together with a brief history of the general subject, by A. Frederick Collins. The first suggestion of a wireless system was by A. G. Bell in 1880. Professor Bell conceived the idea--after the discovery of the variation in resistance of the selenium cell according to the variation in light thrown upon it--that this principle might be used to reproduce spoken words, and such proved to be the case. The speaking arc is another very interesting experiment described; but, as both of these methods depend upon an uninterrupted visual line and more or less accurate alignment of apparatus, it is hardly possible that they can attain much practical importance or be operated over very great distances. In a recent article Mr. Tesla states that "within a few years a simple and inexpensive device, readily carried about, will enable one to receive on land or sea the principal news, to hear a speech, a lecture, a song, or play of a musical instrument conveyed from any other region of the globe." Aside, however, from this prophecy, wireless telephony offers an interesting field for research and experiment, although after 25 years much still remains to be done to place it on a sound commercial footing.