The telephone: an account of the phenomena of electricity, magnetism, and sound, as involved in its action (1877)
Dolbear, A[mos] E[merson], 1837- [from old catalog] · Boston, Lee & Shepard; New York, C. T. Dillingham · leaf 123
an electric cir-cuit ; and, without the slightest knowledge of themechanism which Prof. Bell had used, I devisedthe following arrangement for a speaking-telephone. My first speaking-telephone, Fig. 14, consistedof a magnet made out of half-inch round steelbent into a U form, having the poles about… … FIG. 14. — MY FIRST SPEAKING TELEPHONE. wound with cotton-covered copper wire, No. 23, each bobbin contain-ing about 150 feet.This magnet, with thebobbins slipped uponits poles, was made fastto a post two or threeinches high. The steelwas made as stronglyFIG. 14.—END VIEW. magnetic as was possi-…
Telephone
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