<- Virtual Exhibitions in Informatics


Original Tin-foil Phonograph, 1877

The Phonograph was developed as a result of Thomas Edison's work on two other inventions, the telegraph and the telephone. In 1877, Edison was working on a machine that would transcribe telegraphic messages through indentations on paper tape, which could later be sent over the telegraph repeatedly. This development led Edison to speculate that a telephone message could also be recorded in a similar fashion. He experimented with a diaphragm which had an embossing point and was held against rapidly-moving paraffin paper. The speaking vibrations made indentations in the paper. Edison later changed the paper to a metal cylinder with tin foil wrapped around it. The machine had two diaphragm-and-needle units, one for recording, and one for playback. When one would speak into a mouthpiece, the sound vibrations would be indented onto the cylinder by the recording needle in a vertical (or hill and valley ) groove pattern. Edison gave a sketch of the machine to his mechanic, John Kreusi, to build, which Kreusi supposedly did within 30 hours. Edison immediately tested the machine by speaking the nursery rhyme into the mouthpiece, "Mary had a little lamb." To his amazement, the machine played his words back to him.

Drawing and Sketch of original Phonograph, 1877

Thomas Edison (1847 - 1931)

Thomas Edison with a Phonograph

Born on February 11,1847 in Milan, Ohio; the seventh and last child of Samuel and NancyEdison. When he was seven his family moved to Port Huron, Michigan andEdison lived there until he struck out on his own at the age ofsixteen. He had very little formal education as a child, attendingschool only for a few months. He was taught reading, writing, andarithmetic by his mother, but was always a very curious child andtaught himself much by reading on his own. This belief inself-improvement remained throughout his life.

In sum there are 1,093 patents registered by Thomas Edison.

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