During the war he worked with Enrico Fermi at the University of Chicago, where he earned a Masters of Science, and then returned to MIT, where he got his Ph.D.  During the war Faul worked in the Southwest prospecting for uranium; he married Dorothy Walkley in Cortez, Colorado in 1943.  After the war was over he continued to work with radioactivity, building a mass spectrometer for the Bureau of Standards in Washington, D.C.  In the mid-1960s he accepted a position at the University of Pennsylvania in Philadelphia, where he was chair of the geology department.  Dr. Faul published several books, including "Ages of Rocks, Planets, and Stars," "Nuclear Geology," and "It Began with a Stone," written with his wife Carol Heubusch Faul.  Dr. Faul died of leukemia in 1981.