52 
THE FIRST TELEPHONE. 
Fig. 7. 
later a lid of thin pine was added, against which the listener 
could press his ear. The sounds emitted by such a wire during 
magnetisation and demagnetisation were well-known before, but 
to Reis is due the discovery that other tones than the natural 
vibration-tone of the wure could be electrically imposed upon it 
by the varying magnetising power of the current traversing the 
surrounding coil. Reis explained the reproduction of the trans- 
mitted sounds by supposing a magnetic attraction between the 
atoms of the steel wire to w'ork synchronously with the fluctua- 
tions of the current. He later devised a different receiver in 
which an electromagnet was provided with an elastically-mounted 
armature of iron attached to a light and broad lever, which it 
threw into vibrations corresponding to those of the original 
sound-waves. With this apparatus, and a transmitter with a 
small curved-lever, in shape like that in the “ ear,” he was 
able (see Kuhn’s “ Handbuch der Angewandten Elektricitiits- 
lehre,” 1866, p. 10, Ql), not only to reproduce melodies with 
astonishing exactness, and single words as in speaking and 
reading less distinctly, but even to transmit the inflexions of 
the voice expressive of surprise, command, interrogation, &c. 
Considering how^ far these early researches were carried, it is 
remarkable that their historic value has been so greatly over- 
looked. The transmitters which Reis devised embody — though 
their mechanical design is less perfect and their performance 
consequently less certain— all the essential principles of the 
