These letters, which cover the period February-October 1878, are from Edison to Alfred M. Mayer, a professor of physics at the Stevens Institute of Technology in Hoboken, New Jersey, who published an account of Edison's phonograph in the April 1878 issue of Popular Science Monthly. The letters describe developments in phonographs, telephones, and other experimental matters.

An online finding aid to the archival collection is available.

Courtesy of the Princeton University Libraries.