Alexander G. Bell’s Photophone

Of all of Alexander Graham Bell’s inventions, the one that initially comes to mind is the telephone.  It was a groundbreaking invention that made communication between cities and even states possible.  What few know is that Bell was also working on another invention, one that would make coast-to-coast information transmission possible, wirelessly.  This invention used nothing but the light produced by the sun to transfer voice from a transmitter to a receiver.  The photophone, as it became known, would redirect sunlight against a hair thin mirror, which vibrated as the sound waves from your voice hit against the back of it.  As this was happening, the waves of light were then transferred across the air to the receiver, which of course had to be in direct line of the transmitter.  Bell and his assistant Charles Sumner Tainter viewed this new invention as greater than the telephone.  Their invention would enable the transmission of information without the need for running miles of numerous cables through lakes and across rough terrain.  This also became the precursor to modern day fiber-optic communications.

The first call with the photophone was made on April 1, 1880, from the roof of the Franklin School in Washington, D.C. to Bell’s laboratory window, which was roughly seven hundred feet away. After the successful transmission of sound, Bell was thrilled.  He sent his father a letter stating, “I have heard articulate speech produced by sunlight!  I have heard a ray of the sun laugh and cough and sing!”  He was so proud in fact that he wanted to name his second daughter after the invention.  Bell had hoped that the photophone would negate telephone lines and make ship to shore communication possible.  Unfortunately for Bell and Tainter, the euphoria would be short lived.

Bell and Tainter had invented an apparatus ahead of its time, where people still used candles to light houses and relied primarily on horses for work and transportation.  In 1880, some people still viewed cabled phones with a sort of primitive skepticism.  People were skeptical of such technology and along with that, the duo had to fight against environmental forces as well.  Much like light from the sun, when fog, snow, and rain move in very little light can penetrate the density of the obstructions.  Unlike its modern counterparts like fiber-optic cable, it was unshielded, leaving it completely at the mercy of the weather.  Bell Laboratories continued to try and improve on the photophone long after its invention, hoping to produce one with enough power to negate the weather forces and become a reliable form of communication.  Regrettably, this never came true.

 

Bibliography

Bell, Alexander G. “On the Production and Reproduction of Sound by Light.” The American Journal of Science 20 (1880): 305-324.

Bell, Alexander G. 1880. Apparatus For Signaling and Communicating, Called “Photophone”. U.S. Patent 235,199, Filed August 28, 1880, and Issued December 7, 1880.

Bell, Alexander G. 1880. Photophone-Transmitter. U.S. Patent 235,496, Filed September 25, 1880, and Issued December 14, 1880.

Bruce, Robert V. Bell: Alexander Bell and the Conquest of Solitude, New York: Cornell University Press, 1990.

Carson, Mary K. Alexander Graham Bell: Giving Voice To The World, New York: Sterling Publishing, 2007.

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