22 



FLUORESCENCE OF THE URANYL SALTS. 



curve of distribution to be of the same type as that obtained when the 

 envelope is drawn for the entire spectrum, i. e., the type associated 

 with what we have termed a simple band. (See A in fig. 5, Chapter II, 

 which is the energy curve for the brightest band of uranyl potassium sul- 



.50 //- 



t sloo 



20JOO 



FIG. 9. 



FIG. 10. 



I .55, 



50 /* 



phate with the scale of wave-lengths, adjusted so as to make the width 

 nearly the same as that of the envelope (B] for the same substance.) 



The most striking feature 

 distinguishing these spectra 

 from one another to the eye, 

 excepting where partial resolu- 

 tion occurs, is the vary ing width 

 and sharpness of the bands. 



With the spectrophotometer 

 it is possible to obtain a more 

 definite expression of this fea- 

 ture, as may be seen from fig- 

 ures 12 and 13, in which are 

 depicted, from such measure- 

 ments, the three brightest bands 

 of uranyl nitrate (crystallized) 

 and uranyl potassium sulphate. 

 It will be noted that the bands 

 overlap at the base, but to a 

 greater extent in the nitrate 

 than in the potassium sulphate, where the bands are narrower and 

 more sharply defined. 



19100 



20100 



FIG. 11. 



