This folder contains correspondence and other documents relating to Edison's deafness and to devices for the hearing impaired. Included are letters pertaining to the medical causes of deafness, the use of a phonograph horn as a hearing aid, and the use of phonograph records as a diagnostic tool. At the end of the folder are several undated circulars regarding an instrument called the Magniphone, with a notation by Edison indicating that the device was "n[o] g[ood]." The correspondents for 1919 include eye and ear specialist Dr. Harry P. Engle; Mrs. M. Grimwood, the wife of a retired British army colonel; Henry J. Hauschild of the Hauschild Music Co. in Victoria, Texas; Prof. Klaas Schoolland of Calvin College; and deaf inventor William E. Shaw.
Approximately 20 percent of the documents have been selected. The unselected material consists of requests for advice, opinions, or information about products, along with routine replies stating that Edison did not find any existing hearing aids satisfactory and had not yet developed one of his own but might do so in the future. Courtesy of Thomas Edison National Historical Park.