GERHARD, William Paul, sanitary engineer, born in Hamburg, Germany. 30 July, 1854. He was educated at the gymnasium in Kiel and at the polytechnic school in Carlsruhe, where he was graduated as a civil engineer in 1875. After a year of military service he became an assistant engineer in Hamburg. In September, 1877, he came to the United States and settled in St. Louis, Maine, where he held the offices of assistant engineer in the department of public works, then in the department of water-works, and finally in the sewer department. During 1880 he assisted James B. Eads in the preparation of the plates of the "History of the St. Louis Bridge," and in 1881 became chief assistant to George E. Waring in Newport. He removed to New York in 1883, where for two years he wan chief engineer of the Durham house-drainage company, and since has practiced sanitary engineering, devoting himself particularly to the sanitation of buildings and towns. He is a member of scientific organizations both in Germany and in the United States. During 1885-'6 he edited "Building," and, besides articles on his specialties contributed to technical journals, he has published reports on the sanitary plumbing and drainage of tenement-houses in the annual volumes of the Rhode Island and Connecticut state boards of health. His larger works include " Anlagen yon Haus-Entwasserungen" (Berlin, 1880) ; " Diagram for Sewer Calculations" (London and New York, 1882); " House-Drainage and Sanitary Plumbing" (New York, 1883); "Hints on the Drainage and Sewerage of Dwellings " (1884); " Sanitary Questions" (1884); "Prinzipien der Haus-Kanalization" (Leipsic, 1885); " A Guide to Sanitary House-Inspection" (New York, 1885); "The Prevention of Fire" (1886) ; " Notes embodying the Recent Practice in Sanitary Drainage of Buildings" (1887); " Domestic Sanitary Appliances" (Springfield, 1887) ; and "The Disposal of Household Wastes" (1887).