MY predecessor who in this hall gave the first Arthur Holly Compton Memorial Lecture a year ago was more fortunate than 1. He knew Arthur Compton personally; I never met him., But I have known of Compton since my student days in the nineteen-twenties, and especially since 1925 when the famous experiment of Compton and Simonz refuted the beautiful but short-lived quantum theory of Bohr, Kramers, and Slater.3 This refutation was one of the decisive events in the history of quantum theory, for from the crisis which it created there emerged the so-called `new quantum theory'-the theories of Born and Heisenberg, of Schrodinger, and of Dirac.
