overall: 1/8 in x 12 7/8 in; .3175 cm x 32.7025 cm
center hole: 1/8 in x 1 in; .3175 cm x 2.54 cm
glass disk: 13 1/2 in; 34.29 cm
experimental sound recording
United States: District of Columbia, Washington
This experimental sound recording was made in the Volta Laboratory, Washington, D.C., on 17 November 1884. The recording process involved focusing a beam of light, projecting it through a liquid, and causing sound waves to interrupt both the light and the liquid to expose a prepared photographic plate. This is a variable-area recording, that is, sound is represented by a spiral of that varies in width according to volume and pitch. The process is described in U.S. Patent 341,213 awarded Alexander Graham Bell, Chichester A. Bell, and Charles Sumner Tainter on 4 May 1886.
Sound was recovered from this recording in 2011.
Content (7 seconds): "ba-ro-me-ter" [repeated]
<a href="http://www.phonozoic.net/griffonage/pdfs/volta-discography.pdf">Patrick Feaster, “A Discography of Volta Laboratory Recordings at the National Museum of American History” </a>
Leslie J. Newville, “Development of the Phonograph at Alexander Graham Bell's Volta Laboratory,” in Contributions from the Museum of History and Technology, United States National Museum Bulletin 218, Paper 5 (1959): 69-79.
<a href="http://www.aes.org/aeshc/docs/recording.technology.history/graphophone.html">Steven E. Schoenherr, “Charles Sumner Tainter and the Graphophone,”</a>
Wile, Raymond R. "The Development of Sound Recording at the Volta Laboratory," Association for Recorded Sound Collections Journal 21, No. 2, 1990, pp. 208-225.