Engineer and draftsman with Stearns, Roger Manufacturing Company, 1892-1893. Engineer Metallic Extraction Company, 1894. Operating mines and mills in San Juan Company, Colorado, 1895-1896.
On engineering staff Samuel Newhouse, 1898-1901. Private practice, 1901-1906, inventing Callow settling tank and Callow traveling belt screen. President and manager General Engineering Company, New York, since 1906.
Designed and built 500-ton plant for National Copper Company, Mullan, Idaho, installing pneumatic flotation cells, 1912. Designing and construction engineer, Mount Isa Mines, Australia, 1928-1931. Originator of pneumatic flotation in treatment of ores.
Awarded 18 patents.