118 



FLUORESCENCE OF THE URANYL SALTS. 



TABLE 37. Average frequency intervals, +20 C. and 185 C. continued. 

 General averages of intervals (by salts). 



TABLE 38. General averages of intervals (by series). 



On the other hand, differences so large are not to be regarded as 

 errors of observation, it being possible to determine the average inter- 

 val of any series, excepting possibly A g and A w , which are very weak and 

 rather vague, within about 0.2. It does not follow, however, that the 

 bands are really thus irregularly placed. The discrepancies are due 

 rather to the fact that resolution is not equally complete in all portions 

 of the spectrum and that on cooling the crystal structure was more or 

 less disturbed and the polarization always much less complete. The 

 anomalous values above 84 frequently observed at 185 (see table 

 37) are probably due to varying components of the opposite polar- 

 ization superimposed on the bands in question and producing a false 



