An overview

One hundred years ago Alexander Graham Bell invented the telephone. Shortly thereafter Bell also invented a photophone—a contraption that transmitted human speech on a beam of light. Bell, who had a deep interest in the problems of the deaf, sought ways to make “visible speech.” He had to resort to heroic measures to demonstrate the photophone, using the Sun as the source of light and a Rube‐Goldberg‐like scheme as a modulator. Although the photophone worked, Bell wisely gave it up in favor of copper wires and electrical transmission.

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