31 6 Mr. S. I. Vavilov on Dependence of the Intensity of 



given the curves o£ absorption of all three dyes. The or- 

 dinates or! Fluorescein correspond in the figure to 0'163 xc 

 and for two other dyes xc. The curves are perfectly mono- 

 typical, differing only in the different situation of maximum 

 and the absolute value of xc. This can be proved by a 

 superposition of all three curves. In fig. 3 the curve of 



Fin-. 3. 



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 0,3 





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lV r ''HO H60 t, 



?0 500 520 



Eosin is removed 

 separating the 



to a distance of 45 yu,/x : 



z. e. 



the interval 

 maximum of Fluorescein and Eosin. The 

 curve or Hhodamin is removed to a distance of 65 fi/ju. The 

 ordinates of maxima of all curves are reduced to the same 

 value. On the same figure are marked the points corre- 

 sponding to Eosin of Nichols and Merritt, maximum removed 

 to a distance of 38 fifi. The established regularity allows of 

 several conclusions being drawn : — 



1. All dyes studied by us have the same mechanism of 

 absorption in the visible part of absorption. 



2. The coefficient of absorption is sufficiently approximated 

 by xc=f(\—\ ), 



which is in contradiction with the classical theory for the 

 simple band and likewise for a complex one. 



3. The invariability of the form of the curves by removing 

 their maxima to a distance of 65 /jl/jl, serves as u criterion of 

 the optical cleanness of our preparations. 



4. The same fact serves, of course, as an indirect indication 

 of physical simplicity of the bands of absorption studied. 



