[Fig. 142.—Fessenden wireless telephone transmitting phonograph music.]
[Fig. 143.—Diagram illustrating why damped oscillations will not carry the voice.]
[Fig. 144.—How the sound waves of the voice are impressed upon undamped oscillations.]
[Fig. 145.—Arrangement of the speaking arc.]
[Fig. 146.—Diagram showing how a wireless telephone transmitting system is arranged.]
[Fig. 147.—Poulsen wireless telephone equipment.]
[Fig. 148.—The Majorana wireless telephone transmitter.]
[Fig. 149.—Showing the brush discharge from a Marconi transatlantic aerial at night.]
[Fig. 150.—An amateur wireless' telegraph station.]
[Fig. 151.—The high-power naval wireless telegraph station under construction at Washington, D. C.]