130 A STUDY OF THE ABSORPTION SPECTRA. 



made about 2 weeks before using); strip 2 represents the absorption of the 

 same solution to which 0.5 mm. hydrochloric acid had been added; strip 3 the 

 same as 1 to which 1.2 mm. of hydrochloric acid had been added (in this 

 case a small amount of a brown precipitate was formed causing the absorp- 

 tion to be greatly increased) ; strip 4 represents an ether solution (ether was 

 added to the acetone solution of uranous chloride, a deep green precipi- 

 tate was formed, and the ether became yellow) of probably uranyl chloride; 

 strip 5 represents the absorption of an acetone solution of uranous chloride, 

 freshly prepared, 2 mm. in depth, strip 6 the same 5 mm. in depth, and 

 strip 7, 14 mm. in depth. 



The freshly prepared uranous chloride (in acetone) solution shows the 

 uranous bands very faintly. The addition of hydrochloric acid is seen to 

 bring out the bands very well. In addition to the bands alread} r described 

 faint bands (strip 2) appear at X 6090, X 6340, X 6365, and X 6390. The 

 ether bands occur as follows: a, X 4930; b, X 4760 (a faint component at 

 ,14800); c, A 4600; d, X 4440; e, X 4290; /, X 4155; g, X 4030. The relative 

 shifts of the ether bands relative to the bands of the solution of uranous 

 chloride in hydrochloric acid are very noticeable when the spectrograms are 

 made to overlap. With reference to these bands the ether bands d, e,f, and 

 g are shifted to the red and the a and b bands to the violet. 



Uranous Chloride to which Acetic Acid is Added. 



Plate 94, B, represents a slightly acid solution of uranous chloride in 

 water to which is added glacial acetic acid until there is five times as much 

 glacial acetic acid present as there was of the original solution. The addi- 

 tion of acetic acid causes a marked change in the absorption, a, A49S0, 

 doubles into the bands X 5020 and X 4930; b and c double without being 

 changed very markedly; d, X 4400, is slightly shifted to X 4420; e, X 4280 to 

 X 4300; /, X 4140 to X 4160; and g, X 4010 to X 4030; X 5560 is shifted to 

 X 5590; X 6450 to X 6650 to X 6500; and instead of the band at X 6770 there 

 are two bands X 6650 and X 6800. 



Uranous Bromide. 



Plate 92, A, represents the absorption of an 0.8 mm. depth of 0.5 

 normal uranous bromide in water to which more and more water has been 

 added. The depths of cell are 0.8 mm., 2.8, 12.5, 22, and 35 mm. 



The ultra-violet absorption is but slightly changed by the addition of 

 water. The other uranous bands are narrower the greater the dilution of 

 the uranous bromide. For the upper strip the positions of the bands are 

 X 4280, A 4370 (these bands form practically a single band), X 4850 (very 

 diffuse), X 4970 (these bands merge into each other), X 5400 to X 5600, 

 X 6200 to X 6650 and X 6750. 



Uranyl and Uranous Acetates. 



The action of free acetic acid upon the uranyl absorption bands of an 

 aqueous solution of uranyl acetate is quite small. The bands are made 

 quite narrow and weak. One spectrogram gave b, X 4730; c, X 4610; d, 

 X 4470; e, X 4330; and/, X 4210. This is very similar to the absorption 



