This is the world's oldest audio recording, from an era when today's recording technology seemed fairy tales. American specialists have found and listened an 1860 recording of a folk song. This pre-dated by 17 years the phonograph invented by Thomas Edison, which recorded him singing a children's song in 1877. This was previously considered to be the oldest record.

"It's like a ghost singing to you," said audio historian David Giovannoni.

The 10 seconds record is a fragment from the song "Au clair de la lune, Pierrot repondit" ("By the moonlight, Pierrot replied"). The team at First Sounds, a group of audio historians, recording engineers, sound archivists and other specialists aim to conserve humankind's earliest sound recordings.

"It was made on April 9, 1860, by Parisian inventor Edouard-Leon Scott de Martinville on a device called the phonautograph that scratched sound waves onto a sheet of paper blackened by the smoke of an oil lamp," said Giovannoni.

Lines were marked into the soot by a needle moved by a diaphragm sensitive to sound. One month ago, Giovannoni heard about its existence in an archive in Paris and one week later he was there.

"It doesn't take anything away from Thomas Edison, in my opinion. Thomas Edison is generally credited as the first person to have recorded sound. But actually the truth is he was the first person to have recorded (sound) and played it back. There were several people working along the lines of Scott, including Alexander Graham Bell, in experimenting - trying to write the visual representation of sound before Edison invented the idea of playing it back," Giovannoni told Reuters.

The recording is on display today at a conference of the Association for Recorded Sound Collections at Stanford University in California and very high-resolution digital scans of the paper are also available on the Web. A team at the Lawrence Berkeley National Laboratory in California transformed these scans into sound. But as the phonautograph recordings were made employing a hand-cranked device, the speed varied throughout, varying the pitch.

"It's like discovering the world's oldest photograph and learning that the photograph was taken 17 years before the invention of the camera. In this case, the oldest sound that we can generally hear, up until today, has been from 1888. This predates it by 28 years," said Giovannoni.

"That phonautograph recordings were never intended to be played. What Scott was trying to do was to write down some sort of image of the sound so that he could study it visually. That was his only intent," he added.