e. Since at thisdistance the the desired direction. spoken words were themselves It may be well to explain once perfectly audible across the air, for all how the vibrations of the the telephones connected with voice can affect the intensity of the selenium cell were placed in the reflected beam far… … the disk, and vary, therefore, with every vibration .. = phone little need be said. One device, which in with the utmost fidelity. The receiver of the arti- Fig. 2.—THEORETICAL DIAGRAM OF THE ARTICULATING PHOTOPHONE. Prof. Bell’s hands worked very successfully over a culating photophone is shown on…
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