﻿and the Solvate Theory of Solution. ^ 737 



Absorption Spectra of Neodymium Salts. 



The following nomenclature will be used in describing the 

 neodymium absorption spectra. 



ol group in the region A 3400 to A 3600. 



8 „ at about A 4300. 



7 „ from A 4600 to X 4800. 



S „ from A 5000 to A 5400. 



e ,, in the region A 5800. 



f „ at A 6300. 



In designating the neodymium spectra we start from the 

 violet end of the spectrum. This is the natural method when 

 a grating is used. It is doubtful whether, in the near future, 

 the ultra-violet spectrum of neodymium can be studied much 

 farther than we have done, so that this is the natural end of 

 the spectrum at which to begin. It is, on the other hand, 

 probable that there are many neodymium bands farther down 

 in the infra-red than we have gone ; and when these have 

 been worked out they can then be named in the natural 

 order. 



The change in the absorption spectrum of neodymium 

 chloride as the solvent is changed can be seen best by ex- 

 pressing the results in the following form. The abbreviations 

 nsed are: "d" diffuse, "fa" faint, "G." fine, "h" hazy, 

 "i" intense, "n" narrow, "sh" sharp, "st" strong, 

 " we " weak, " wi " wide. 



The following results (pp. 738-9) obtained with neodymium 

 chloride show the effect of the solvent on the absorption spectra 

 of solutions of this compound. The bands of the different 

 solvents have different wave-lengths and different relative 

 intensities. 



Having found that the solvent played an important part in 

 determining the absorption of light by the dissolved sub- 

 stances, Jones and Strong used isomeric organic solvents to 

 see whether such closely related compounds would affect 

 differently the power of substances dissolved in them to 

 absorb light. They prepared solutions of neodymium chloride 

 in propyl and isopropyl alcohols, and in butyl and isobutyl 

 alcohols, and photographed the absorption spectra of this salt 

 in these isomeric solvents. The following results show different 

 absorption lines and bands in the isomeric solvents. 



Phil. Mag. S. 6. Vol. 23. No. 137. May 1912. 3 C 



