The 10-second clip of a woman singing "Au Clair de la Lune," taken from a so-called phonautogram, was recently discovered by audio historian David Giovannoni. The recording predates Thomas Edison's "Mary had a little lamb" — previously credited as the oldest recorded voice — by 17 years.
The tune was captured using a phonautograph, a device created by Parisian inventor Edouard-Leon Scott de Martinville that created visual recordings of sound waves.
Using a needle that moved in response to sound, the phonautograph etched sound waves into paper coated with soot from an oil lamp.
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Nifty yet spooky.