These documents cover the years 1881-1940 and fall into three groups. The items from 1881 and 1882 consist of correspondence, agreements, instructions, technical specifications, and test reports relating to dynamos designed and built by Charles L. Clarke, chief engineer of the Edison Electric Light Co. of New York. Included are numerous reports of dynamo tests made at the Paris Electrical Exhibition of 1881. Other correspondents and experimenters mentioned in these documents include William S. Andrews, Charles L. Dean, Julius L. Hornig, and Thomas Logan.
The second group comprises correspondence, 1927-1929, between representatives of Henry Ford in Detroit and the General Electric Co. in Schenectady. The letters relate to replicas of Edison's early dynamos that were built for use in Light's Golden Jubilee at the reconstructed Menlo Park laboratory in Dearborn. Correspondents on Ford's side include James W. Bishop of the Detroit Edison Co.; Frank Campsall, Ford's personal secretary; and Francis Jehl, curator of the Ford Museum. Correspondents for General Electric include Clarke, Schenectady engineer C. J. Leephart, and Detroit sales agent V. J. Snyder.
Finally, there is a 19-page essay, written by Clarke in 1930, concerning his earliest work for Edison at Menlo Park in 1880, along with a series of letters, 1931-1940, to Francis Jehl. The letters include discussion of Clarke's personal affairs, reminiscences about specific individuals, and detailed comments on Jehl's Edison-related publications.