In 1860 Philipp Reis, as we have seen, produced a telephone which could
transmit musical notes, and even a lisping word or two; and some ten
years later Mr. Cromwell Fleetwood Varley, F.R.S., a well-known English
electrician, patented a number of ingenious devices for applying the
musical telephone to transmit messages by dividing the notes into short
or long signals, after the Morse code, which could be interpreted by
the ear or by the eye in causing them to mark a moving paper. These
inventions were not put in practice; but four years afterwards Herr Paul
la Cour, a Danish inventor, experimented with a similar appliance on a
line of telegraph between Copenhagen and Fredericia in Jutland. In
this a vibrating tuning-fork interrupted the current, which, after
traversing the line, passed through an electro-magnet, and attracted
the limbs of another fork, making it strike a note like the transmitting
fork. By breaking up the note at the sending station with a signalling
key, the message was heard as a series of long and short hums.
Moreover, the hums were made to record themselves on paper by turning
the electro-magnetic receiver into a relay, which actuated a Morse
printer by means of a local battery.
Mr. Elisha Gray, of Chicago, also devised a tone telegraph of this kind
about the same time as Herr La Cour.
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