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Vannevar Bush comparator patent, 17 February 1959. This is the 2nd of nine sheets of the application filed with the US Patent Office on 23 October 1946 by US electrical engineer Vannevar Bush (1890-1974) for a design for an electronic comparator. Bush's early work on this was at the Massachusetts Institute of Technology (MIT) from 1927, developing a digital analyser and analogue computers. The optical-electronic comparator that Bush built for the US Navy in 1938 proved unreliable. It was used for ballistics analysis and for breaking codes during World War II. The technology was part of the memex system proposed by Bush after the war. (KEYSTONE/SCIENCE PHOTO LIBRARY/US NATIONAL ARCHIVES/SCIENCE PHOTO LIBRARY)