He continued to work at Harvard, being appointed an instructor in mathematics from 1930 until 1935, although the years 1931-33 were spent as a National Research Council Research Fellow at Harvard and Princeton.
Siya ang patuloy na magtrabaho sa Harvard, na hinirang ng magtuturo sa matematika mula 1930 hanggang 1935, bagaman ang taon 1931-33 ay ginugol bilang isang National Research Council Research Fellow sa Harvard at Princeton.