The Russellville Democrat., 1881-02-03
The rhotophsne.
st. Louls Republlcan.

The rapid progress reported to have been made by Prof. Graham Bell in de- veloping his discovery of the photophone
 promises to make this instrument one of the most important products of modern
 research. Lord Bacon once said that q
 true scientific generalization once made
 troops of practical applications will soon
 follow The history of all investigations
 in the dark and untrodden domain of molecular physics is not an exception to
 this remark of the great inductive phi-
 losopher, but furnishes most brilliant
 illustrations of it's force It is unneces- sary to trace in detail how the modern electric light, the electric engine, the tel
 ephone and telegraph became the natur- al, we might almost say the inevitable, results of Faraday's and other experi-
 ments in the laboratory conducted with a view to test antecedent hypotheses, the glimmer of whose light lured on the the oretical investigator to new and unex- plored regions of physical inquiry. In the case of the photophone the instru- mental device of Prof. Bell is the out come of experiments upon the curious action of light in affecting the electric cond1ctiyity of the rare metal selenium. This metal was discovered in 1877 by the celebrated Swedish chemist Berzelius. and now promises to figure conspicuous ly in the future utilization of the photo phone. The photophone is an instru- ment for the transmission of artificial sound to distant stations solely through the agency of beam of light. It effects the transmission of sound not by means of an electric wire, or, indeed, by any material medium, but, like the ancient -4o rf Fsx Strabo, gave forth a mysterious sound every morning as the rays of the sun fell upon 1t, the new instrument converts the waves of light thrown upon it into waves of audible and intelligible sound. Its practical operation is due to the sensi- tiveness of the selenium plates, by means of which the impact of rays of light of varying intensity is made sensible to the ear. The transmitting instrument is simply plane and flexible mirror of thin glass or mica, against the back of which the speakers voice is directed at the same time that powerful beam of light is cast upon the mirror, while the vibrations flashed to the distant receiving instru- ment cause it's sensitive selenium disk to reproduce and rearticulate the original words of the speaker. Wherever, there fore, a beam of light, solar or artificial, can be thrown there the photophone can be employed for communication.
 The difficulties yet to be overcome be- fore the photophohe can be put in prac- tical use are to determine how far it will serve to transmit messages and to over- come the optical difficulties in managing the beam of light. To perfect it will probably require much further experi- mentation, for which purpose it's inven- tor is now in Europe at work with em- inent scientific advice. But as Prof. Huxley says, "such, an instrument may evidently become of great value in estab- fishing rapid communication between distant surveying stations and especially in military signalling where it promises to displace the heliograph" While the field of it's ability may not be as wide as that of the telephone, it will probably serve an important purpose in many cir cumstances where electric wires can not be placed for telephonic communication.