Success and Survival
In 1917, as the United States entered World War I, another completely different namesake "C" tube was invented as the General Electric Laboratory collaborated with other companies in the war effort. This prototype device detected and indicated submarine traffic using an arrangement of pipes attached to an acoustic detector.
During the following years, the General Electric Research Laboratory grew in prominence and Coolidge, now Assistant Director, continued his work in the application of X-ray technology. Willis Whitney retired from the laboratory in 1932 and leadership passed to William Coolidge. Coolidge succeeded in maintaining the organization's survival through the difficult economic conditions of the 1930s Depression and positioned it as an important part of the defense effort in World War II, when he played a part in research on the atomic bomb.
Near the end of the war, on December 31, 1944, Coolidge retired from the General Electric Research Laboratory yet maintained his interest in X-ray applications. He lived to be 102 and died on February 4, 1945.