concerned the source of the Earth's magnetic field. He was often frustrated by efforts to increase geophysical interest at the University of Cambridge. In his career he won the Hughes Medal, the Vetlesen Prize and the Gold Medal of the Royal Astronomical Society. He was elected to the American Academy of Arts and Sciences in 1954. In 1965, he was awarded the Alexander Agassiz Medal from the National Academy of Sciences, of which he was a member, for his significant investigations of the earth from its surface to its core. He was elected to the American Philosophical Society in 1969. Then during the early 1960s Bullard and his associates used a computer to try to fit all of the continents together. Instead of using the shorelines, as other geophysicists had done, he used a depth of 914 meters (3000 ft) below sea level. This depth corresponds to about halfway between the shoreline and the ocean basins and represents the true edge of the continents. By doing this he discovered a near perfect fit among the continents put together. With this discovery he helped further the idea of a supercontinent that an earlier geophysicist, Alfred Wegener, had suggested calling Pangaea. It turned out a posteriori that a very similar result had been published thirty years earlier by the French geologist Boris Choubert, but this work published in French in a francophone journal of low international influence had remained virtually unknown. After retiring from Cambridge in 1974 he settled to a position at the University of California, San Diego. Bullard died in La Jolla, California, in 1980. His papers are held by the Churchill Archives Centre. See also List of geophysicists References Further reading External links Bullard photo Cambridge article 1907 births 1980 deaths Geologists from Norwich People educated at Norwich School Alumni of Clare College, Cambridge University of Toronto faculty Fellows of Churchill College, Cambridge British geophysicists Fellows of the Royal Society Foreign associates of the National Academy of Sciences Knights Bachelor Wollaston Medal winners Royal Medal winners Recipients of the Gold Medal of the Royal Astronomical Society Scientists of the National Physical Laboratory (United Kingdom) Tectonicists Marine geophysicists British expatriates in Canada British expatriates in the United States Members of the American Philosophical Society