National Telegraphic Union · New York : N.T.U. · leaf 320
Fig. 2.—The Meceiver. Fig. 1.—Transmitting Apparatus. covery, but of a thorough study of the laws of electro-magnetism and of sound. It is founded on the fact thatthe difference in pitch of different tones is caused bydifferent velocities of vibrations of the elastic soundingbody; which vibrations…
Telegraph
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