Page:Popular Science Monthly Volume 19.djvu/343

Fig. 11.

Fig. 11. a.

ceiver (F) by the action of the same current, would be found capable of extinguishing the effect produced in the receiver (G) by the action of the undulatory beam of light, in which case it should be possible to establish an acoustic balance between the effects produced by light and electricity by introducing sufficient resistance into the electric circuit.

Upon the Nature of the Rays that produce Sonorous Effects in Different Substances.—In my paper read before the American Association last August, and in the present paper, I have used the word "light" in its usual rather than its scientific sense, and I have not hitherto attempted to discriminate the effects produced by the different constituents of ordinary light—the thermal, luminous, and actinic rays. I find, however, that the adoption of the word "photophone" by Mr. Tainter and myself has led to the assumption that we believed the audible effects discovered by us to be due entirely to the action of luminous rays. The meaning we have uniformly attached to the words "photophone" and "light" will be obvious from the following: passage, quoted from my Boston paper:

Although effects are produced, as above shown, by forms of radiant energy, which are invisible, we have named the apparatus for the production and reproduction of sound in this way the "photophone," because an ordinary beam of light contains the rays which are operative.

To avoid in future any misunderstandings upon this point, we have decided to adopt the term "radiophone," proposed by M.