URANIUM SALTS. 97 



A, Plate 58, is a spectrogram to test Beer's law, the length of exposures 

 and concentrations being the same as for B. Instead of the depth of cell 

 being constant, this was changed so that the product of depth of cell and 

 concentration remained constant. Beer's law was found to hold. In this 

 spectrogram the a band is shown to be broken up into two other bands. 

 The a and b bands also obey Beer's law. In the ultra-violet there is a faint 

 transmission band. This also is unaffected by change in concentration. 



Uranyl Chloride in Glycerol. 



A and B, Plate 59, represent the absorption spectra of a solution of 

 uranyl chloride in glycerol, the depth of cell being 10 and 5 mm., respec- 

 tively. The concentrations, starting with the strip nearest the scale, were 

 0.176, 0.132, 0.088, 0.059, 0.041, 0.032, and 0.022 normal. The spectro- 

 grams are very similar to those of the other uranyl salts. The blue-violet 

 absorption band vanishes at about X 4300. The positions of the uranyl 

 bands are: a, 5050; c, 4720; d, 4540; e, 4400; /, 4260; g, 4140; h, 4025; 

 and 3920. 



The uranyl bands of a glycerol solution are quite broad. The same is 

 true of the uranous bands. Glycerol usually has the effect of making the 

 bands less dense than they appear for most of the other solvents. In a few 

 cases the bands are quite fine, however, as in the case of the erbium and 

 neodymium salts. 



Uranyl Chloride in Mixtures of Glycerol and Methyl Alcohol. 



Spectrograms A and B (Plate 60) represent the absorption of a 

 solution of uranyl chloride in mixtures of glycerol and methyl alcohol. 

 The depth of cell for A was 25 mm., B 3 mm. The concentration of uranyl 

 chloride was 0.0176 normal. The percentages of methyl alcohol were 0, 15, 

 30, 45, 60, 75, and 90. 



The general ultra-violet absorption remains about the same for the 

 various mixtures of the solvents. The uranyl bands change but slightly, 

 the b, c, and d bands being the only ones that change. The b band of the 

 upper strip has a weak component at X 4800, the c band at X 4660, and the 

 d band appears double. The wave-lengths of the bands remain practically 

 the same as for the pure glycerol solution. The methyl alcohol bands, 

 however, are quite different in position from the glycerol bands, and from 

 these spectrograms we see that practically all the change must occur 

 between a 90 per cent and a 100 per cent methyl alcohol mixture; the 

 glycerol bands being much more persistent than the alcohol bands. 



Uranyl Chloride in Acetone and the Effect of Hydrochloric Acid on the Uranyl 



Acetate Bands. 



A solution of uranyl chloride (3 grams in 100 c.c. acetone) was made 

 and the absorption spectra of depths of layer of 3, 6, and 15 mm. were 

 taken. Depths of 1.5, 3, and 9 mm. were then used of the above acetone 

 solution, to which an equal volume of strong hydrochloric acid had been 

 added. The addition of hydrochloric acid causes the solution to become 

 very red. Upon the spectrogram there were 7 strips. The addition of 

 7 



