Fluorescence of Dyes on Wave-Length of Exciting Light. 319 



• Table III. 



Eosin S extra. c = l'20 . lO' 5 ^ ; d = 0"83. 

 A. F. <p. k. 



13 473 ^ 0-0845 930 9-05.10-3 



5 475 0-247 27'7 8-91 



11 477 0-160 18-1 8-80 



10 487 0-470 52-0 9-02 



4 495 0-615 68*9 8-97 



528 6-42 725 887 



7 534 3-00 330 909 



6 542 0-570 6-55 8-69 



3 547 1-48 167 8-85 



Table IV. 

 Rhodamin B extra. c = 2'4 . lO" 6 ^; d = 0'S'd. 



X. F. <p. k. 



5 478 mi 0-364 10 6 3-43.10-2 



10 492 8-25 23-9 3-46 



4 513 1-67 48-5 3-45 



9 544 11-4 318 3-58 



547 29-1 809 360 



7 552 15-8 447 3/53 



3 559 12-6 339 3'70 



2 579 1-05 29-2 3-60 



Table III. gives the same result for Eosin. The deviation 

 of k reaches 5 per cent.; according to Einstein, there must 

 exist the increase of 16 per cent. 



For Rhodamin there is a small increase o£ k with 

 wave-length, which lies still inside the limit of errors of 

 experiment. The greatest deviation is 8 per cent. This 

 systematic deviation can be possibly explained by the 

 existence of some discordance between the Angstrom equa- 

 tion (9) and the true distribution of energy in the spectrum 

 of the Hefner's candle. According to Einstein, the value of 

 k must increase in this case by 21 per cent. 



In other less careful measurements of /c the deviations 

 amounted to 10 to 14 per cent. 



Conclusions. 



(1) Within the limits of errors of observation the specific 

 fluorescence of our dyes is independent of A, within their 

 band of absorption. 



