The Rutherford Memorial Lecture, 1958

Abstract

Five years ago in this University Sir James Chadwick gave the second Rutherford Memorial Lecture. I have read it many times and find it an admirable account of Rutherford’s scientific career and a wise and understanding description of his outstanding genius as an experimental physicist. Chadwick gave special emphasis to Rutherford’s remarkable achievements during his tenure of the MacDonald Chair of Physics here at McGill and to the great debt that the world of science owes to this University in giving such excellent facilities to such a young man. Together with the four other Memorial Lectures given under the auspices of the Royal Society, a very complete account has been given of Rutherford’s life and achievements. I will not attempt to recapitulate the story, but will content myself with a commentary on certain aspects of Rutherford’s attitude to the art of the experimenter which seem to be of special interest today. Here in McGill the exponential decay with time of radioactive substances was first observed and interpreted as being due to spontaneous disintegration of an atom. A quarter of a century elapsed before this brilliant phenomenological interpretation by Rutherford and Soddy was to receive a theoretical explanation in terms of wave mechanics. Today, with the surprising developments of the last decade and the discovery of whole families of unstable elementary particles, we now see that the spontaneous decay of one subatomic bit of matter into lighter pieces is one of the most significant facts of the subatomic world. In point of fact, these families of elementary particles are superficially not unlike the families of radioactive elements which Rutherford and his co-workers did so much to disentangle. An outstanding difference is, of course, that no one has found a theoretical explanation of the spontaneous decay of elementary particles and most theorists believe that none is to be sought, but that such behaviour is just a fundamental property of microscopic matter.