Description

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ELECTRONS (+ and-), PROTONS, PHOTONS, NEUTRONS, MESOTRONS, AND COSMIC RAYS. originally published in 1934. PREFACE: In 1917 the University pf Chicago Press published a small volume entitled The Electron which was intended to be a rather simple presentation of some of the newer de velopments in physics with which my own work had been closely associated. In 1924 a revised edition of this work appeared. A few years later I had the honor of giving The Messenger Lectures at Cornell University and in them still further expanded and brought up to date these newer developments. The present volume grows immediately out of these Messenger Lectures, but is, of course, an attempt to make the presentation as true a picture as I am able to give of the situation as it exists at the date of publication, Janu ary i, 1935. In a sense this work may be looked upon as a third re vision of The Electron, but it differs from most revisions in two particulars, First, an effort has been made at the request of the publishers to introduce into The Electron portion only such changes as are demanded by correct ness of presentation today, and in fact I have been pleased and somewhat surprised to find that the historical mode of presentation originally adopted has rendered radical changes even today both unnecessary and undesirable. Second, the growth of discovery and the rapidity of the advance in physics from the base occupied in 1924 has made it altogether necessary to add six entirely new chap ters ( ad to rvi) on ' Waves and Particles, on The Dis ' ccfvby anVl OrigJ* i; 6f the'Cosmic Rays/' on The Spin ning Elecr& h$ on The Positron, on The Neutron an.