Bell's 'Harmonic' telegraph transmitter and receiver, 1873-1874.
© Science Museum / Science & Society Picture Library
Replica. After experimenting with various acoustical devices, Bell (1847-1922) produced the first intelligible telephonic transmision with a mesage to his asistant on 5 June 1875. He patented this device as the telephone in 1876, a patent he had to defend against Elisha Gray. Bell, who became a naturalised American in 1874, also invented the phonograph (1880) and the gramophone (1887). Among Bell's other achievements was the photophone which transmitted sound on a beam of light - a precursor of today's optical fibre systems, and the invention of techniques for teaching speech to the deaf.