These documents, which cover the years 1879-1887, were selected from boxes 14, 15, and 19 in Series 1 of the William J. Hammer Collection. They consist primarily of drawings of electrical apparatus, including incandescent lamps, lamp fixtures, thermostat alarms, keyless sockets, electric cigar lighters, branding tools, electric curtains for theaters, and electricians' tools. Also included are several drawings relating to the flashing electric sign that Hammer demonstrated at the London Crystal Palace Exhibition of 1882 and the Berlin Exposition of 1883. Some of the other drawings from 1882-1884 may also have been made in connection with these exhibitions. In addition, there are notes pertaining to lamp manufacture and life tests and to a test of Edison's "big dynamo." Although most of the items bear dates, the dates and inscriptions in some cases appear to have been assigned at a later time, and some of the drawings may be copies rather than originals. Courtesy of the NMAH Archives Center.