 He left Cambridge in 1945 to be a lecturer in the Department of Physics at University College, Cardiff becoming in 1954 Professor of Physics and Director of the Viriamu Jones Laboratory, a post he held until 1965.There he founded a school of organic crystal chemistry which achieved world-wide recognition for its work on alkaloids and other organic substances.In the late 1940s he demonstrated that the symmetry elements of a crystal structure can be deduced from observed diffraction data.