﻿734 Prof. H. C. Jones on Absorption Spectra 



It was soon found that an aqueous solution of uranyl 

 chloride shows absorption bands in different positions from 

 those of solutions in methyl alcohol. These differences were 

 sufficiently great to merit careful study. 



What these differences are can be best seen by giving the 

 wave-leno-ths of a few bands in the different solvents. 



o 



Uranyl Chloride. 



In water XX4025, 4170, 4315, 4460, 4560, 4740, and 4020 



In methyl alcohol... XX4090, 4220, 4345, 4465, 4590, 4760, and 4930 



In ethyl alcohol ... XX4100, 4250, 4400, 4580, 4750, and 4900 



In propyl alcohol ... XX4100, 4230, 4400, 4580, 4750, and 4910 



In isopropyl alcohol XX4100, 4250, 4360, 4560, 4750 



In butyl alcohol ... XX4100, 4240; 4390, 4560, 4750, and 4970 



In isobutyl alcohol . XX 4400, 4560, 4720, and 4900 



In ether XX4040, 4160. 4300, 4444, and 4630 



In methyl ester AX4030, 4160, 4280, 4440, 4620, 4790, and 4920 



In glycerol XX4025, 4140. 4260, 4400, 4540, 4720, and 5050 



In formamide XX 4450, 4650, and 4840 



The absorption spectra of uranyl nitrate in mixtures of 

 water and methyl alcohol were photographed. The absorption 

 in pure methyl alcohol was much greater than in pure water. 

 As water was added to the alcoholic solution the absorption 

 became less and less. In the mixed solvents the bands became 

 very broad. A careful study of the structure of these broad 

 bands showed that they were the "water" and "alcohol'"' 

 bands coexisting ; and not one set of bands shifted in position, 

 and this, as we shall see, is an important point. 



A simple method of reducing uranyl to uranous salts in 

 solution was found to be the action of nascent hydrogen. 

 This was obtained by introducing into the aqueous solution 

 of the uranyl salt a bar of zinc, and then adding the acid of the 

 salt in question. In this way uranous salts could be prepared, 

 and several of them were found to have sufficient stability for 

 our purpose. Uranous chloride, uranous bromide, and uranous 

 acetate were thus made and their absorption spectra photo- 

 graphed and studied. These salts proved to be very useful 

 for the detection of " solvent " bands, or the effect of the 

 solvent on the absorption spectra of salts dissolved in it. The 

 uranous bands are numerous, and what is far more important 

 for our work, they are well defined with comparatively sharp 

 edoes, and their wave-lengths can be accurately determined. 

 In this respect they are second only to certain lines of 



