CONTENTS. 



Chapter I. Introduction 1 



Chapter II. The Absorption Spectra of Aqueous Solutions as Affected 



by Temperature 5 



The Making of a Spectrogram 7 



Neodymium Chloride in Water 8 



Neodymium Bromide in Water 9 



Neodymium Nitrate in Water 9 



Neodymium Acetate in Water 11 



Neodymium Sulphate in Water 12 



Cobalt Chloride in Water 12 



Praseodymium Chloride in Water 13 



Praseodymium Nitrate in Water 13 



Uranyl Nitrate in Water 14 



Uranyl Sulphate in Water 14 



Uranyl Acetate in Water 15 



Chapter III. The Effect of Dilution on the Absorption of Light by 



Solutions 17 



Making a Dilution Spectrogram 18 



Neodymium Chloride in Water 18 



Neodymium Bromide in Mater 20 



Neodymium Nitrate in Water 20 



Neodymium Sulphate in Water 21 



Neodymium Acetate in Water 22 



Praseodymium Chloride in Water 23 



Praseodymium Nitrate in Water 24 



Uranyl Chloride in Water 24 



Uranyl Bromide in Water 24 



Uranyl Nitrate in Water 2.5 



Chapter IV. The Absorption Spectra of Aqueous Solutions of Certain 



Salts of Neodymium a.s Studied by Means of the Radiomicrometer . 29 



Method of Procedure 31 



Discussion of the Results 36 



Possible Explanation 38 



Chapter V. The Absorption of Light by Water Changed in the Presence 

 of Strongly Hydrated Salts, as Shown by the Radiomicrometer. 



New Evidence for the Solvate Theory of Solution 43 



Absorption of Free and Combined Water 43 



Hydrated and Nonhydrated Substances 44 



Method of Procedure 44 



Results 45 



Discussion of the Results 52 



Explanation of the Results 54 



Chapter VI. Absorption Spectra of a Number of Salts as Measured by 



Means of the Radio.micrometer 61 



Mode of Procedure 62 



Description of Cells Used 63 



Discussion of Tables and Curves 65 



Neodymium Chloride in Water 65 



Neodymium Nitrate 72 



Neodymium Acetate 74 



Praseodymium Chloride 76 



Praseodymium Nitrate 78 



Nickel Chloride 79 



Nickel Nitrate 80 



Nickel Sulphate 80 



Salts of Cobalt 81 



Chapter VII. General Summary of Results 85 



v 



