Hazen also worked with Bush over twenty years on such projects as the mechanical differential analyzer.
This early work, and the binary algebra used, would be foundational to the emergence of electromechanical and digital computers in later decades.
[1] After 1937 Hazen became increasingly involved in teaching and administrative work, becoming Head of department in 1938 and serving for fourteen years.
From December 1942 until 1946 he was head of Division 7, "Fire Control", of the NDRC (National Defence Research Committee).
[3] In his later life Dr. Hazen promoted engineering education programs both in the United States and internationally.