In reality it was a mere
sounding box, and the cord was a steel rod that conveyed the vibrations
of the music from the several instruments which were played out of sight
and ear-shot. At this period Wheatstone made numerous experiments on
sound and its transmission. Some of his results are preserved in
Thomson's ANNALS OF PHILOSOPHY for 1823. He recognised that sound is
propagated by waves or oscillations of the atmosphere, as light by
undulations of the luminiferous ether. Water, and solid bodies, such as
glass, or metal, or sonorous wood, convey the modulations with high
velocity, and he conceived the plan of transmitting sound-signals,
music, or speech to long distances by this means. He estimated that
sound would travel 200 miles a second through solid rods, and proposed
to telegraph from London to Edinburgh in this way. He even called his
arrangement a 'telephone.' [Robert Hooke, in his MICROGRAPHIA, published
in 1667, writes: 'I can assure the reader that I have, by the help of a
distended wire, propagated the sound to a very considerable distance in
an instant, or with as seemingly quick a motion as that of light.' Nor
was it essential the wire should be straight; it might be bent into
angles. This property is the basis of the mechanical or lover's
telephone, said to have been known to the Chinese many centuries ago.
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