Now it occurred to Professor Hughes that, if this were so, it might be
possible to cause the air-vibrations of sound to so act upon a wire
conveying a current as to stretch and contract it in sympathy with
themselves, so that the sound-waves would create corresponding electric
waves in the current, and these electric waves, passed through a
telephone connected to the wire, would cause the telephone to give forth
the original sounds. He first set about trying the effect of vibrating
a wire in which a current flowed, to see if the stretching and
compressing thereby produced would affect the current so as to cause
sounds in a telephone connected up in circuit with the wire--but without
effect. He could hear no sound whatever in the telephone. Then he
stretched the wire till it broke altogether, and as the metal began to
rupture he heard a distinct grating in the telephone, followed by a
sharp 'click,' when the wire sundered, which indicated a 'rush' of
electricity through the telephone. This pointed out to him that the
wire might be sensitive to sound when in a state of fracture. Acting on
the hint, he placed the two broken ends of the wire together again, and
kept them so by the application of a definite pressure. To his joy he
found that he had discovered what he had been in search of.
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