VI PREFACE. 



A form of apparatus has been devised which enables us to measure 

 the intensities of the absorption bands in aqueous and nonaqueous solu- 

 tions, over a range of temperature; and work is now in progress on this 

 part of the problem. 



As soon as sufficient work has been done on inorganic compounds we 

 intend to take up organic substances and study them by the same general 

 methods that we have used with the inorganic. 



For the conductivity measurements recorded in this monograph we 

 are indebted to Dr. A. P West and Mr. H. H. Hosford. 



It gives me pleasure to express my thanks to Professor Ames for the 

 loan of the grating used in this work, and for the ample space placed at 

 our disposal in carrying out this investigation. 



Harry C. Jones. 



