Edouard-Léon Scott de Martinville invented sound recording 20 years before Thomas Edison invented the phonograph, by conceiving of a machine that would do for the ear what the camera did for the eye. His invention—the phonautograph—was patented on March 25th, 1857 in France.
It did not occur to anyone, not even Scott de Martinville, that the phonautograms created by his machine might contain enough information about the sound they recorded that they could be used to recreate it.
In fact, in a presentation given to SEIN (Société d’encouragement pour l’industrie nationale)—an association of experts that assessed new technologies and their potential contributions to French industry—Scott de Martinville described his invention as “an entirely new graphic art springing from the heart of physics, of physiology, of mechanics.” (Emphasis the author’s.) Hence, his own self-description from his journals that supplies the title of this post: “the imprudent idea of photographing the word.”
And it is true that phonautograms cannot be physically played back: they were created exclusively to function as a visual representation of sound, and are formed as a line traced on smoke-darkened paper or glass. An example can be seen below:
They could be used to study waveforms of speech, but the idea that someone might be able to use them to reproduce sound was a long way off. It would not be until 2008 that audio historians at Indiana University would successfully play 1861 phonautograms as sound by using an optical scanner and using a computer to process the scans into digital audio files.
Many of the extant phonautograph recordings we still have are of Scott de Martinville’s own voice. To test his invention, he sang songs and recited excerpts of poetry and plays in several languages. In recognition of the cultural significance of this recordings, the Library of Congress inducted them into its recording registry in 2011, and UNESCO soon followed suit in 2015 by inscribing them into the World Memory Register.
To learn more about Scott de Martinville’s invention, and about the legacy of the recordings themselves, the ARSC First Sounds bio should be your go-to source. The site provides access to digitized facsimiles of every dossier Scott de Martinville ever produced related to his invention. Particularly worth noting are Patrick Feaster’s definitive annotated bibliography/discography, and the high-resolution scans of Scott de Martinville’s patent documents, which contain the only known sketches of the phonautograph.