Page:Popular Science Monthly Volume 12.djvu/587

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dangerous practice of 'tapping the wires,' which may make it useful or dangerous, according as it is used for proper or improper purposes. It might be an important addition for a military commander to make to his flying cavalry; as an expert sound-reader, accompanying a column sent to cut off the enemy's telegraph-connections, might precede the act of destruction by robbing him of some of his secrets. The rapidity and simplicity of the means by which a wire could be 'milked,' without being cut or put out of circuit, struck the whole of the party engaged in the various trials that are described above. Of course, the process of tapping by telephone could not be carried out if the instrument in use was an A B C or single needle, or if the wire was being worked duplex or with a fast-speed Morse, for in these cases the sounds are too rapid or too indefinite to be read by ear. The danger is thus limited to ordinary sounder or Morse telegraphs; but these still form the mainstay of every public system.

"Since the trials above described were made, the newspapers have recorded a beautiful application, by Sir William Thomson, of the electric part of the telephone to exhibit at a distance the motions of an anemometer; the object being to show the force of air-currents in coal-mines. This is a useful application of an electric fact, and doubtless points the way to further discoveries. But it is to be noticed that the experiment, interesting as it is, hardly comes under the head of a telephone, what is reproduced at a distance being not sound but motion.

"Obviously the invention cannot rest where it is; and no one more readily than the practical telegraphist will welcome an instrument at once simple, direct, and reliable. Even in its present form the telephone may be successfully used where its wire is absolutely isolated from all other telegraph-wires. But the general impression is that its power of reproducing the sound must be intensified before its use can become general, or come up to the popular expectation."

The realization of so marvelous a device as the telephone cannot fail to stimulate speculation as to where such wonders will stop. If words may be converted into electricity and back again into words, what is to hinder their being converted into something more lasting than electricity—something that will endure, so that spoken words may be reproduced in the future exactly as spoken now; that persons, though dead, may yet speak? What is to hinder? Nothing! The thing is already done; the spirit of the Phonograph has taken on more than a shadowy form, as will be explained to our readers next month. And what next?—

"Ah! Science, give us one more link,

That we may hear our neighbors think."