CONTENTS. 



BOOK I. THE BASIS OF THE INQUIRY. 



CHAP. PAGE 



I. Principles and Methods ... ... ... ... ... 1 



II. Some Pioneering Difficulties ... ... ... ... 18 



III. The Present Position 29 



BOOK IL APPLICATION OF THE INQUIEY TO 

 THE SUN AND STARS. 



IV. The Sun's Chromosphere 38 



V. Stellar Atmospheres ... ... ... ... ... 45 



VI. The Chemistry of the Stars ... 55 



VII. A Chemical Classification of Stars ... 66 



BOOK III. THE DISSOCIATION HYPOTHESIS. 



VIII. Recent Opinion 73 



IX. Stellar Evidence 78 



X. " Series " Evidence 83 



XI. "Shifting "of Lines Evidence 101 



XII. Magnetic Perturbation Evidence ... ... ... 109 



XIII. Fractionation Evidence . 116 



BOOK IV. OBJECTIONS TO THE DISSOCIATION 

 HYPOTHESIS. 



XIV. The Chemistry of Space 120 



XV. The General Distribution of Stars 124 



XVI. The Distribution of Chemical Groups of Stars ... 129 



XVII. The Result of the Inquiry ... ... ... ... 141 



XVIII. Replies to Special Objections ... ... ... ... 144 



