McMillan, Edwin Mattison, 1907-91, American physicist, b. Redondo Beach, Calif., grad. California Institute of Technology, 1928, Ph.D. Princeton, 1932. On the faculty of the Univ. of California from 1932, he was appointed professor of physics in 1946 and director of the Lawrence Radiation Laboratory (now the Lawrence Berkeley National Laboratory) in 1958. With P. H. Abelson he discovered neptunium (element 93) and with Glenn Seaborg and others, plutonium (element 94). For his work on the chemistry of the transuranium elements he shared the 1951 Nobel Prize in Chemistry with Seaborg. He also contributed to microwave radar and sonar, and to the design of particle accelerators. He worked (1942-45) on the atomic bomb at Los Alamos.