American chemist; born at San Francisco Feb. 18, 1863; educated at the San Francisco College of Pharmacy, the University of California, Johns Hopkins University, and at Zurich, Liége, Munich, and Paris. Lengfeld has been fellow of Johns Hopkins University (1887-88), professor of chemistry in the South Dakota School of Mines (1890-91), instructor in chemistry at the University of California (1891-92), and docent-instructor and assistant professor in chemistry at the University of Chicago (1892-1901). He is the author of "Laboratory Manual of Inorganic Preparations," and has contributed numerous articles to American and foreign journals of science.