Early the same morning Kennedy went around again to the apartment
house and, cautious not to be seen by Flirty, recovered the
telegraphone. Together we carried it to the laboratory.
There he set up a little instrument that looked like a wedge
sitting up on end, in the face of which was a dial. Through it he
began to run the wire from the spools, and, taking an earpiece,
put another on my head over my ears.
"You see," he explained, "the principle on which this is based is
that a mass of tempered steel may be impressed with and will
retain magnetic fluxes varying in density and in sign in adjacent
portions of itself--little deposits of magnetic impulse.
"When the telegraphone is attached to the telephone wire, the
currents that affect the receiver also affect the coils of the
telegraphone and the disturbance set up causes a deposit of
magnetic impulse on the steel wire.
"When the wire is again run past these coils with a receiver such
as I have here in circuit with the coils, a light vibration is set
up in the receiver diaphragm which reproduces the sound of
speech." He turned a switch and we listened eagerly. There was no
grating and thumping, as he controlled the running off of the
wire. We were listening to everything that had been said over the
telephone during the time since we left the machine.
Pages:
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242