100 



A STUDY OF THE ABSORPTION SPECTRA. 



Uranyl Nitrate in Mixtures of Glycerol, Water, Acetone, and Ethyl Alcohol. 

 Plate 09, A and B, represents the absorption of solutions 25 and mm. 

 in depth, respectively. Strip 1 represents the absorption of a solution of 

 uranyl nitrate in glycerol; strip 2 of 3 parts glycerol and 1 part water; 

 strip 3 of 2 parts glycerol and 2 parts water; strip 4 of 1 part glycerol and 

 3 parts water; strip 5 of 1 part glycerol and 3 parts acetone, and strip of 

 1 part glycerol and 3 parts ethyl alcohol. The concentration of uranyl 

 nitrate in glycerol was the same in each case. 



Plate - B brings out clearly the fact that the addition of water causes 

 the uranyl nitrate bands of glycerol to be gradually shifted towards the 

 violet. The above identification of the acetone and methyl alcohol bands 

 isopen to correction. 



Uranyl Nitrate, Temperature Effect. 



A spectrogram was made of a 0.0150 normal uranyl nitrate solution in 

 water, the depth of layer being 190 mm. Exposures were made to the Nernst 

 glower for 30 seconds, the current being 0.8 ampere and the slit-width 

 0.20 mm. The length of exposure to the spark was 4 minutes. Starting 

 with the strip nearest the scale, the temperatures were 9, 23, 40, 59, 70, 

 and 79. 



At 9 the ultra-violet absorption band extended to A 3430. Throughout 

 the blue-violet band there was considerable transmission at this temperature, 

 the stronger spark lines being only partially absorbed. The a, b, and c bands 

 appeared, all being extremely weak, however, and in quite striking contrast 

 with their strength in the aqueous solutions investigated in the earlier part 

 of the work. Their wave-lengths were U 4550, 4705, and 4870. 



As the temperature was raised, both the ultra-violet and the blue- 

 violet bands widened. The intensity of the uranyl bands, on the other 

 hand, did not seem to vary with the temperature. At 79 the ultra-violet 

 band extends to A 3550. The blue-violet band extends from /t 3900 to A 4450. 

 Only the a and b bands appear at this temperature, their positions being 

 A 4710 and A 4875. There may be a slight shift towards the red, but if 

 there is, it is too small in amount to be established with certainty. 



