Edward Crisp Bullard, an English geophysicist who, along with Maurice Ewing, is generally considered to have founded the discipline of marine geophysics, was born on September 21, 1907, in Norwich, England. He was educated at Repton School and Clare College, Cambridge, taking first-class honors in physics in 1929 and earning his PhD in 1932. During World War II Bullard conducted military research, investigating magnetic mines and the demagnetizing of ships; he would continue to advise the Ministry of Defence for several years after the war.
In 1947 Bullard became professor of geophysics at the University of Toronto, Canada. It was there that he developed his “dynamo” theory of geomagnetism, according to which the Earth’s magnetic field results from convective movements of molten material within the Earth’s core. He stayed in Toronto three years before returning to the UK to become director of the National Physical Laboratory. He was knighted in 1953. In 1957 Bullard returned to Cambridge to head the department of geodesy and geophysics, a position he would hold until 1974. He was also a professor at the University of California from 1963, and advised the U.S. government on nuclear-waste disposal.
Bullard's earliest work involved timing the swings of an invariant pendulum to measure minute gravitational variations in the East African Rift Valley. He then investigated the rate of efflux of the Earth's interior heat through the land surface. He pioneered the application of the seismic method to study the sea floor, and made the first satisfactory measurements of geothermal heat-flow through the oceanic crust. Bullard was also one of the first to develop the theory of continental drift. Studying the rifted continental borders along the two sides of the Atlantic Ocean, he tested their precise fitting by computer-based analyses and presented his results to the Royal Society of London: The fit was perfect.
In addition to his knighthood, Bullard was made Fellow of the Royal Society (FRS) in 1941, received the Day Medal of the Geological Society of America in 1959 and was awarded the Royal Medal of the Royal Society in 1975. Sir Edward died on April 3, 1980.