Alexander Graham Bell (1847-1922) inventor of the telephone, aged 29. After experimenting with various acoustic devices, Bell produced the first intelligible telephone 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.
© Science Museum / Science & Society Picture Library