 He did postdoctoral work at the Polytechnic Institute of Brooklyn.During World War II, he worked for the Admiralty Research Laboratory, from which emerged a group of many notable scientists, including David Bates, Robert Boyd, George Deacon, John Gunn, Harrie Massey, and Nevill Mott; he worked on the design of magnetic and acoustic mines, and was instrumental in designing a new mine that was effective against German minesweepers.In 1947, aged 31, Crick began studying biology and became part of an important migration of physical scientists into biology research.