194 



FLUORESCENCE OF THE URANYL SALTS. 



fact is that the bands of the 1.5, 0.5, and 0.05 normal solutions are not 

 shifted by temperature, and that dilution from 3.0 normal to 0.05 

 normal produces a negligible shift. There is no tendency toward reso- 

 lution. Clearly, the uranyl chloride in aqueous solution furnishes 

 spectra of great stability, especially in view of the behavior of the 

 bands of the uranyl nitrate. 



URANYL NITRATE IN WATER. 



The solutions of uranyl nitrate present at once the most interesting 

 and most complicated spectra. In our first investigations the solutions 

 were studied at 185 after suddenly plunging them into liquid air. 

 Later it became of interest to study them at several intermediate 



NITRATE IN WATER. -180 



^rv A yi\/!\ 



2. 



4. 



/ML 



5. 



II 



J I 



IN WATER. 



-180 



M. 



XT\ 



NITRATE IN NITRIC ACID. -180* 



r.io 



1:10 



1:3.5 



1800 



20|00 



FIG. 96. 



temperatures and the freezing and subsequent cooling was of necessity 

 done slowly. To our surprise, the normal solution of the nitrate 

 yielded an entirely different type of spectrum. Spectrum No. 1 at the 

 top of figure 96 represents the old type and spectrum No. 5 the new 

 type. It was found possible to produce intermediate degrees of resolu- 

 tion somewhat similar to Nos. 2, 3, and 4 by intermediate rates of 

 cooling. The pertinent fact is that the identical solution could, by 



