viii CONTENTS. 



Chapter 111 continued. page. 



The Absorption Spectrum of Dysprosium 4b 



Dysprosium Chloride in Water 47 



Dysprosium Chloride in Methyl Alcohol 47 



Dysprosium Chloride in Ethyl Alcohol 47 



Dysprosium Acetate in Water 48 



The Absorption Spectrum of Samarium 48 



Samarium Chloride in Water 48 



Samarium Nitrate in Water 49 



Samarium Chloride in Methyl and Ethyl Alcohols 49 



Samarium Chloride in Water and Ethyl Alcohol 50 



Chapter IV. The Spectrophotography of Chemical Reactions: 



Introduction 51 



Phosphorescence of Praseodymium in Calcium Oxide 54 



Phosphorescence of Neodymium in Calcium Oxide 54 



Phosphorescence of Erbium in Calcium Oxide 54 



Phosphorescence of Praseodymium in Calcium Sulphate 54 



Phosphorescence of Erbium in Calcium Sulphate 54 



Phosphorescence of Erbium in Calcium Fluoride 54 



Neodymium Chloride in Ethyl Acetate and Anthracene 56 



The Uranyl and Uranous Bands 57 



The Oxidization of Uranous to Uranyl Salts in Solution 58 



The ( bridization of Uranous Chloride by Hydrogen Peroxide 58 



Oxidization of Uranous Chloride in Hydrochloric Acid by Hydrogen Peroxide 60 



The Oxidization of Uranous Sulphate 61 



The Oxidization of Uranous Bromide by Hydrogen Peroxide 61 



A Possible Method of Measuring the Strengths of Acids 62 



Are the Ions Factors in the Absorption of Light ? 62 



The Oxidization of Uranous Salts by Nitric Acid 64 



Uranous Acetate and the Effect of the Addition of Nitric Acid 65 



The Selective Action of Chemical Reagents on Solvates 66 



The Reduction of Uranyl Salts in Solution 69 



Reduction of Uranyl Chloride in Methyl Ester 69 



Selective Reduction of Uranyl Aggregates 70 



Direct Spectroscopic Evidence for the Effect of Mass 71 



Chapter V. The Effect of Temperature on Absorption Spectra: 



Solvates and the Effect of Change in Temperature on the Relative Intensity of 



Solvate Bands 7.4 



Neodymium Chloride in Water and Ethyl Alcohol 77 



Neodymium Bromide in Water and Methyl Alcohol 77 



Neodymium Chloride, Bromide, and Nitrate in Water 77 



Neodymium Chloride in Methyl Alcohol 78 



Neodymium Bromide in Methyl Alcohol 79 



Neodymium Nitrate in Isobutyl Alcohol 79 



Neodymium Nitrate in Acetone 80 



Erbium Chloride in Water 80 



I franyl Chloride in Acetone 81 



Uranyl Nitrate in Propyl Alcohol 81 



I Iranyl Chloride and Nitrate in Isobutyl Alcohol 81 



I i-anyl Chloride and Nitrate in Methyl Ester 81 



Uranous Chloride in Water and Methyl Alcohol 82 



I ranous Chloride in Acetone 82 



The Existence of Aggregates and Their Properties, and the Effect of Rise in Tem- 

 perature on the Aggregates 83 



Neodymium Salts in Acid Solutions 84 



Uranous Sulphate in Sulphuric Acid 85 



Uranyl Nitrate in Nitric Acid, Uranyl Chloride in Hydrochloric Acid, and 



iranyl Sulphate in Sulphuric Acid 86 



Chapter VI. Summary and General Discussion: 



Mapping of Spectra 87 



A Theory of Absorption Spectra 89 



Solvation 92 



The Uranyl and I'ranous Bands 94 



Aggregates and Their Properties 95 



The Effect of Temperature on Absorption Spectra 98 



Description of Plates 101 



Index 102 



