He devised some
ten or twelve different forms, each an improvement on its predecessors,
which transmitted music fairly well, and even a word or two of speech
with more or less perfection. But the apparatus failed as a practical
means of talking to a distance.
The discovery of the microphone by Professor Hughes has enabled us to
understand the reason of this failure. The transmitter of Reis was
based on the plan of interrupting the current, and the spring was
intended to close the contact after it had been opened by the shock of a
vibration. So long as the sound was a musical tone it proved efficient,
for a musical tone is a regular succession of vibrations. But the
vibrations of speech are irregular and complicated, and in order to
transmit them the current has to be varied in strength without being
altogether broken. The waves excited in the air by the voice should
merely produce corresponding waves in the current. In short, the
current ought to UNDULATE in sympathy with the oscillations of the air.
It appears from the report of Herr Von Legat, inspector of the Royal
Prussian Telegraphs, on the Reis telephone, published in 1862, that the
inventor was quite aware of this principle, but his instrument was not
well adapted to apply it.
Pages:
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225