which has not passed thru the dye is of the same intensity as that 

 which has passed thru the dye cell. A reading of the extinction 

 coefficient is then made. Further readings may be made at inter- 

 vals of 10 fjLfjL, with intermediate determinations in the immediate 

 vicinity of the maximum absorption or at any other point at 



IS 



1.15 



to.. 



75 



.5 ' 



.25 



42.0 



4£0 



500 



540 



5&Q 



6Z0 



ebo ><>* 



Fig. 4. Absorption curve of victoria green. 



vhich it may appear desirable to bring out detail. If extinction 

 coefficients are then plotted against wave length a graphic repre- 

 lentation of the absorption band of the dye is obtained. 



If measurements are carried out under suitable standardized 

 conditions, the spectral position and the general form of the ab- 



29 



