STUDIES IN LUMINESCENCE. 



The curves in Fig. 31 show the observed values of / as a function of \ 

 for six different concentrations of the solution. The shift in the maximum 

 caused by a change in concentration is here well marked. 



Table 8 gives the result of correcting values in Table 6 for absorption 

 according to the above formula, the value of /, which is proportional to 

 actual fluorescence intensity (see page 34), being found in each case. These 



C 15 



10 



o 



-o 



4> 



O 



0.70JJ 



Observed fluorescence intensity, showing shift of maxi- 

 mum, with change in concentration. 



055>J 

 Fig- 3- 



0.60^1 



0.65>J 



1'luorescence curves corrected for 

 absorption. 



values are plotted in Fig. 32 according to an arbitrary vertical scale which 

 makes the height of each curve approximately proportional to intensity 

 of fluorescence for the corresponding concentration. It will be observed 

 that these curves are similar in form, the maximum wave-length being 

 approximately the same, about 0.595 fi. 



For purposes of comparison a series of measurements was made to 

 determine the relative intensity of different concentrations at wave-length 

 0.589 n, keeping all conditions constant. Table 9 shows the results. In 

 Fig. t,^ the curve marked O gives the actual observed fluorescence. The 



200 ""* c 



50 



100 



32 ie 



Fig. 33. Concentration and fluorescence. 

 Intensity of observed and corrected fluorescence for different concentrations at wave length 0.589 n. 



