These letters cover the years 1890-1892 and 1915-1916. The first group consists primarily of correspondence between Arthur E. Kennelly, director of the Galvanometer Room at the West Orange laboratory, and astronomer Edward S. Holden of the Lick Observatory near San Jose, California. Included are letters relating to plans to light the Observatory by electricity and the donation of the illuminating plant by the Edison General Electric Co. Also included are letters discussing the variation of gravity with temperature, Edison's idea that magnetic iron-ore bodies could be used to receive electromagnetic waves from space, and a photograph of a sun spot that Holden sent to Edison in 1892. Some of Kennelly's letters are original versions, more legible and complete, of the copies in the Arthur E. Kennelly Letterbooks, West Orange Laboratory Records (Thomas A. Edison Papers, Part III, (1887-1898)).
The second group includes letters by Edison and William W. Campbell, director of the Observatory, pertaining to the Edison family's visit to California in 1915 and the Campbell family's trip to West Orange in 1916. Related articles about Edison's visit to the Lick Observatory can be found in the Unbound Clippings Series.
Correspondence not selected includes letters from the San Francisco Edison General Electric Co., 1891-1892, and from the San Francisco office of the General Electric Co., 1904, concerning the installation (supervised by James A. Lighthipe) of illuminating plants for the Observatory. Also not selected are letters between Campbell and Robert E. Ely regarding a Civic Forum dinner honoring Edison in 1915, along with several letters by Kennelly not related to Edison. Courtesy of The Mary Lea Shane Archives of the Lick Observatory, University of California -- Santa Cruz.