The practical telephone handbook and guide to the telephonic exchange (1906)
Poole, Joseph · New York, Macmillan Co. · leaf 73
he particles of water. Wave motion in air is caused bya movement of the particles of air backward and forwardin a line with the direction in which the wave progresses.Every different sound needs a different motion of the airparticles for its conveyance, and if the characteristic motionof any sound… … Fig. 33 is shown in Fig. 33, where e is an electro-magnet mounted soas to be adjustable near the centre of a membrane, m, of gold-beaters skin, stretched over the end of a hollow cylinder. Asmall piece of clock-spring is cemented to the centre of the mem-brane. Two of these instruments, some…
Telephone
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