A broader picture of Rutherford’s geophysicists

Greg Good’s fascinating article compares the careers of two geophysicists, Edward Bullard and Patrick Blackett. Both went to the Cavendish Laboratory, but that is about all they have in common.

Harold Jeffreys and Maurice Ewing, two equally prominent geophysicists who were contemporaries of Bullard and Blackett and are also mentioned in Good’s article, were not Cavendish people. The major problem they faced was how to reconstruct the structure and inner processes of Earth from surface data only. They may have recognized that the problem was ill-posed and that it could only be solved numerically. But their approaches were different: Bullard and Ewing used controlled explosive sources to constrain the solution, while Jeffreys used Bayesian statistics. Their views had much to do with their approaches. Jeffreys, in the fifth edition of his treatise The Earth: Its Origin, History, and Physical Constitution (Cambridge University Press, 1970), adopted my viscoelastic Earth model and thus unwittingly opened the door to plate tectonics.

Incidentally, Good claims that Jeffreys was “a fellow of Trinity College.” He was not. He became a fellow of St. John’s in 1914 and held successive fellowships thereafter under different titles, always at St. John’s. I was his guest at St. John’s College in the late 1950s.