HARPER'S LIBRARY _of_ LIVING THOUGHT [Illustration: HARPER'S LIBRARY _of_ LIVING THOUGHT] "Wie Alles sich zum Ganzen webt Eins in dem andern wirkt und lebt!" THE ETHER OF SPACE BY SIR OLIVER LODGE, F.R.S. HARPER & BROTHERS LONDON & NEW YORK [Illustration: FIG. 15. View of Ether machine complete and in action. (See Chapter V, and figs. 12 and 13.) _Frontispiece_] THE ETHER OF SPACE BY SIR OLIVER LODGE, F.R.S. _D. Sc. Lond., Hon. D. Sc. Oxon. et Vict._ _LL.D. St. Andrews, Glasgow, and Aberdeen_ _Vice-President of the Institution of Electrical Engineers_ _Rumford Medallist of the Royal Society_ _Ex-President of the Physical Society of London_ _Late Professor of Physics in the University College of Liverpool_ _Honorary Member of the American Philosophical Society of Philadelphia; of the Manchester Philosophical Society; of the Batavian_ _Society of Rotterdam; and of the Academy of Sciences of Bologna_ _Principal of the University of Birmingham_ ILLUSTRATED LONDON AND NEW YORK HARPER & BROTHERS 45 ALBEMARLE STREET, W. 1909 _Copyright, 1909, by Harper & Brothers All rights reserved_ PREFACE Investigation of the nature and properties of the Ether of Space has long been for me the most fascinating branch of Physics, and I welcome the opportunity of attempting to make generally known the conclusions to which I have so far been led on this great and perhaps inexhaustible subject. OLIVER LODGE. UNIVERSITY OF BIRMINGHAM, _March, 1909_. TO THE FOUNDERS OF UNIVERSITY COLLEGE, LIVERPOOL, ESPECIALLY TO THOSE BEARING THE NAMES OF RATHBONE AND OF HOLT THIS BOOK IS INSCRIBED CONTENTS CHAPTER PAGE INTRODUCTION. GENERAL AND HISTORICAL xi I. THE LUMINIFEROUS ETHER AND THE MODERN THEORY OF LIGHT 1 II. THE INTERSTELLAR ETHER AS A CONNECTING MEDIUM 13 III. INFLUENCE OF MOTION ON VARIOUS PHENOMENA 29 IV. EXPERIMENTS ON THE ETHER 44 V. SPECIAL EXPERIMENT ON ETHERIAL VISCOSITY 67 VI. ETHERIAL DENSITY 80 VII. FURTHER EXPLANATIONS CONCERNING THE DENSITY AND ENERGY OF THE ETHER 87 VIII. ETHER AND MATTER 98 IX. STRENGTH OF THE ETHER 115 X. GENERAL THEORY OF ABERRATION 127 APPENDIX 1. ON GRAVITY AND ETHERIAL TENSION 143