We could not, for example, arrive at a principle like that of entropy without introducing some additional principle, such as randomness, to this topography.

An outstanding teacher; two of his pupils won Nobel Prizes. He emigrated to Germany working at the Kaiser Wilhelm Institute and then to England working at the University of Manchester. He pioneered the theory of fiber diffraction analysis in 1921 and the dislocation theory of plastic deformation of ductile metals and other materials in 1934.