232 JONES-STRONG— THE ABSORPTION SPECTRA [April 24, 



should give the bands of the same wave-lengths for very dilute 

 solutions. 



The uranyl bands of the nitrate in methyl alcohol are all shifted 

 to the red about 50 Angstrom units, with reference to the bands in 

 water. Mixtures of water and methyl alcohol show that we have 

 both sets of bands existing for the same solution, the " water " 

 bands increasing in intensity as the amount of water increases. The 

 water bands are the more persistent. This indicates the existence 

 of a hydrate and an alcoholate of the uranyl group. In ethyl 

 alcohol the a, b, c and d bands are shifted to the red with reference 

 to the methyl alcohol bands. The other bands appear to have the 

 same positions as the methyl alcohol bands. 



The absorption spectrum of the anhydrous salt is very complex 

 and the bands could not be recognized. 



The bands of uranyl bromide in water, of uranyl acetate in 

 water and methyl alcohol, and also of the anhydrous salt, are ap- 

 proximately of the same wave-lengths, differing but slightly from 

 the wave-lengths of the uranyl nitrate bands of an aqueous solution. 



The bands of uranyl sulphate in water are all shifted towards 

 the red about 50 Angstrom units, with reference to the uranyl 

 nitrate bands in water. For both the sulphate and nitrate in water 

 the bands are very much alike. The i band is very weak in both 

 cases. 



Uranyl chloride bands of an aqueous solution are shifted to the 

 red with reference to the uranyl nitrate bands of an alcoholic solu- 

 tion. The addition of calcium chloride or aluminium chloride is 

 found to produce very marked effects upon the uranyl chloride 

 bands. The addition of sufficient aluminium chloride to a water 

 solution of uranyl chloride, or of calcium chloride to a methyl 

 alcohol solution of uranyl chloride is found to cause the d and e 

 bands to come together, so as to form a single wide band, and to 

 cause the other uranyl bands to shift so that the whole resulting 

 series of bands is almost identical with the series of bands of an 

 ethyl alcohol solution of uranyl chloride. The eflfect of adding 

 foreign substances also greatly modifies the intensity of the bands. 

 An example of this difference of action is the effect of adding 

 aluminium chloride to an aqueous solution of uranyl chloride. The 



