Undergraduate atmosphere at University of Cambridge: course work, lecturers, extra-curricular groups, training experiments in radioactivity and scintillation-counting; obtains old radon tubes for neutron experiments while doing radioactivity work with Robert W. Woods at Johns Hopkins University in 1929; discussions with James Chadwick of Joliot papers, 1932; move with Chadwick to University of Liverpool, 1935; return to University of Cambridge 1936; reaction to selection of William Bragg as Ernest Rutherford's successor; shift in Cavendish Laboratory's world role in nuclear physics; World War II service at Cambridge: administration, teaching, measurement of fission cross-sections; move to University of Edinburgh to replace Charles D. Barkla, 1945.