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 128
plate. I have generally gotthe best results from a plate one-fiftieth of an inchthick. The upright board carrying this platemust be very rigid, otherwise the plate will be kept HOW TO MAKE A TELEPHONE. 123 tight to the magnets all the time ; and one ofthe conditions of success in working is, that… … FIG. 17. The sounds to be transmitted, of whatever sortthey may be, are to be made on the side P, Fig.16 ; and likewise, when the instrument is used asa receiver, the ear is to be applied at the sameplace. A tube about two inches in diameter maybe made fast to the front of the board, in a line 124…
Telephone
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