These documents, which cover the period October 1874-November 1878, relate to George F. Barker, a professor of physics at the University of Pennsylvania who helped to publicize Edison's inventions during the 1870s. Included are letters to Barker from academics, entrepreneurs, inventors, and scientists associated with Edison and the promotion of his early inventions. Several items pertain to public demonstrations of Edison's electromotograph, telephone, and phonograph. Other letters discuss Edison's discovery of "etheric force" and his efforts to invent an electric lighting system. Also included is a letter from inventor Elisha Gray claiming priority in the invention of the telephone and commenting on his competition with Edison.
An online finding aid to the archival collection is available. Courtesy of the University of Pennsylvania Archives.