Youth and early education; undergraduate years at Caltech, 1924-1929; influence of Arthur A. Noyes, Linus Pauling; graduate training and molecular beam work at Princeton University with Karl Compton, Edward U. Condon, Robert Van de Graaff, 1929-1932. National Research Council Fellow at University of California at Berkeley, 1932-1934; at Radiation Laboratory with Ernest O. Lawrence, J. Robert Oppenheimer; on Berkeley staff as teacher and working on cyclotrons, nuclear physics and radiochemistry, 1934-1940.