These three documents, which cover the years 1881 and 1882, were selected from box 23 in Series 2 ("Edisonia") of the William J. Hammer Collection. Included are two estimates of the construction cost of the generating station on Pearl Street in downtown Manhattan. Also included is one small sheet on which Hammer noted the date, time, and place at which the excavation for the Pearl Street district's underground conductors was begun. Courtesy of the NMAH Archives Center.