FLUORESCENCE AND ABSORPTION OF THE URANYL SALTS. 19 



TABLE 7. Fluorescence bands of the double sulphates 

 continued. 



TABLE 8. Fluorescence bands of two acetates. 



RELATIVE INTENSITIES OF THE 

 BANDS. 



To indicate graphically the 1 

 relative intensities of the bands, 

 we may plot their strength, ex- 

 pressed in terms of energy, as 

 ordinates and wave-lengths of the 

 crests as abscissae. 



The resulting curve (see figs. 

 7, 8, 9, and 10) is a sort of enve- 

 lope for the entire spectrum cor- 

 responding to the curve of distri- 

 bution of energy. It resembles in 

 type the curve of energy found 

 in the case of the broad, single- 

 banded fluorescence described in 

 earlier communications / being 



single-crested and steeper toward the violet. As has been pointed 

 out in Chapter II, these curves are very similar to the energy curve 

 for temperature radiation. 



Figure 7 contains the envelopes thus plotted of 5 uranyl double 

 sulphates. Of these, 4 have their crests at approximately the same 

 wave-length (0.515ju). Curve E (caesium uranyl sulphate) is shifted 

 slightly, an effect due to the presence of a strong component of each 

 band on the violet side of the main crest which influences the estimates 



1 Nichols and Merritt, Physical Review (1), xvm, p. 403; xix, p. 18. 



