Elementary lessons in electricity and magnetism (1906)
Thompson, Silvanus P. (Silvanus Phillips), 1851-1916, Schwetzky, Otto H. L. [from old catalog] · Chicago, Thompson & Thomas · leaf 443
ng vibrations. Edison has also in-vented a Telephone Receiver of singular power, whichdepends upon a curious fact discovered by himself, namely, CHAP. xiL] ELECTRICITY AND MAGNETISM. 417 that if a platinum point presses against a rotating cylinderof moist chalk, the friction is reduced when a… … Fig. 169. 436 {bis). Dolbears Telephone.—Telephone Re-ceivers have also been invented by Varley and Dolbear,in which the attraction between the oppositely-electrifiedarmatures of a condenser is utilised in the production ofsounds. The transmitter is .placed in circuit with theprimary wire of a…
Electricity · Magnetism
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