These letters from Edison to Henry A. Rowland, a prominent physicist at Johns Hopkins University, cover the period July 1880-July 1884. Included is correspondence pertaining to patent applications for two inventions by Rowland—a magneto and a dynamo. Also included is a letter discussing the technical details of Edison's incandescent lamp and comparing it with the lamps of his rivals Hiram S. Maxim and Joseph W. Swan.
An online finding aid to the archival collection is available. Courtesy of the Milton S. Eisenhower Library.