He was accepted into Harvard graduate school, with the choice of a fellowship or assistantship. He chose the assistantship, during which he worked for Percy W. Bridgman. He followed Bridgman's courses in fundamental physics and was introduced into the then-new quantum physics with the courses of E. C. Kemble. He completed the work for the Ph.D. in three years by publishing his (1924) paper "Compressibility of the Alkali Halides", which embodied the thesis work he had done under Bridgman. His heart was in theory, and his first publication was not his doctor's thesis, but a note (1924) to Nature on "Radiation and Atoms."