Headstone of Alexander Graham Bell (1847-1922) in Highgate Cemetery, London. After experimenting with various acoustical devices, Bell 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. Bell also invented the photophone in 1880, and the graphophone in 1887. The photophone worked by transmitting sound on a beam of light. The graphophone was a version of the phonograph designed to play 6" long records made from a cardboard tube.
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