One of a pair of home made Bell telephone receivers, probably made by David Edward Hughes, England, 1875-1890.

One of a pair of homemade Bell telephone receivers, probably made by David Edward Hughes, England, 1875-1890.

In 1879 David Edward Hughes (1829/31-1900) was carrying out some experiments with his induction balance. He found that if a circuit was formed by joining up in series a battery, a microphone and one of the coils of his balance, any interruption of the circuit was accompanied by a disturbance which became audible in a telephone receiver connected to another microphone, even when the circuits were widely separated and there was no direct connection between them. It is now known that Hughes had unwittingly discovered electromagnetic radiation, but scientific friends considered the results were due to electromagnetic induction. Discouraged, Hughes did not publish his discoveries and the credit went to Heinrich Hertz some seven years later. This is one of the homemade telephone receivers which Hughes is believed to have used as part of the apparatus for detecting the electromagnetic radiation produced by the interruptor circuit. The waves could be detected inside his house but at no great distance beyond.