These eleven documents, which were selected from boxes 24-27 in Series 2 ("Edisonia") of the William J. Hammer Collection, relate primarily to electric lamp experiments and manufacture. Included are a few notebook pages by Edison concerning coatings for metal lamp burners; blueprint copies of Hammer's drawings of vacuum pumps for the lamp factory; curve sheets of lamp life tests; cost estimates of central station operating expenses; and steam boiler test results by Julius Hornig. Also included are some 1884 notes by Hammer describing earlier lamp experiments and observations of lamp phenomena later ascribed to the "Edison effect." In addition, there are newspaper clippings from 1881 and 1889 relating to the development of Edison's electric light. The last document is a list compiled by Hammer of Edison workers at the Menlo Park and West Orange laboratories, as well as the Edison Machine Works, Bergmann & Co., and Edison General Electric Co. The list of Menlo Park employees is extensive, and there are enumerations of duties and job descriptions for many of them. Courtesy of the NMAH Archives Center.