Concept
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The Inventions of the Telephone and Electricity
Patent drawing for Alexander Graham Bell's telephone, March 7, 1876
Bell's telephone was the first apparatus to transmit human speech via machine. His work culminated in one of the most profitable and contested of all nineteenth-century patents.
Source
Boundless vets and curates high-quality, openly licensed content from around the Internet. This particular resource used the following sources:
"TelephonePatentDrawingBell."
http://en.wikipedia.org/wiki/File:TelephonePatentDrawingBell.jpg
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