Rays of Positive Electricity and Their Application to Chemical Analyses

by Joseph John Thomson

Preface

I have endeavoured in this book to give some account of the experiments on Positive Rays which have been made at the Cavendish Laboratory during the last seven years, and which have been the subject of papers scattered through the Philosophical Magazine, the Proceedings of the Royal Society, and the Proceedings of the Cambridge Philosophical Society. I have, in addition, included a short account of the researches of Stark and others on the Doppler effect in Positive Rays and of Gehrcke and Reichenheim's experiments on Anode Rays, as these, those on the Doppler effect especially, are very closely connected with the results obtained by the very different methods described in the earlier part of this book. I have described at some length the application of Positive Rays to chemical .analysis ; one of the main reasons for writing this book was the hope that it might induce others, and especially chemists, to try this method of analysis. I feel sure that there are many problems in Chemistry which could be solved with far greater ease by this than by any other method. The method is surprisingly sensitive — more so even than that of Spectrum Analysis, requires ,an infinitesimal amount of material, and does not require this to be specially purified: the technique is not difficult if appliances for high vacua are available. I am glad to be able to take this opportunity of expressing my obligations to Mr. F. W. Aston, B.A., and Mr. E. Evrett. My thanks also are due to the President and Council of the Royal Society for permission to use the blocks Illustrating my Bakerian Lecture.

J. J. Thomson

Cambridge, 4 October, 1913.

Contents

• Rays of Positive Electricity
• Double Cathodes
• Rectilinear Propagation of the Positive Rays

  On the Nature of the Positive Rays, Their Deflection by Electric and Magnetic Forces|On the Nature of the Positive Rays, Their Deflection by Electric and Magnetic Forces

• Electrostatic Deflection of the Particle
• Wien's Proof of the Magnetic and Electric Deflection of the Rays
• Effect at Very Low Pressures
• Discussion of the Photographs
• Negatively Charged Particles
• Atoms Carrying Two or More Positive Charges
• Methods for Measuring the Number of the Positively Electric Fied Particles

  On the Information Afforded by the Positive Rays as to the Constitution of a Gas, the Nature and Properties of the Molecules, and the Process of Ionization in a Discharge Tube

• Retrograde and Anode Rays
• Anode Rays
• Doppler Effect Shown by the Positive Rays

  Ratio of Displacements of the Two Maxima

• Spectra Produced by Bombardment with Positive Rays
• Disintegration of Metals Under the Action of Positive Rays
• On The Use of the Positive Rays for Chemical Analysis
• On the Nature of X₃ the Substance Giving the 3 Line
• Evolution of Helium and Neon
• Index