1903.] 



The Cosmical Function of the Green Plant. 



will divide our spectrum into two halves with reference to the 

 diffraction spectrum. The analytical results obtained may conse- 

 quently be directly compared and plotted on a diffraction spectrum. 



They may be stated thus : if the quantity of carbon dioxide reduced 

 in the yellow half be represented (as a mean of six experiments) by 

 100, the effect of the blue half will be 54 (fig. 6B). The principal 



760. 



700 



400. 



result is that the effect of the blue and violet rays has been till now 

 somewhat underrated. 



The same result has been obtained with regard to the iodine starch 

 test, the spectrum being divided as just described in the horizontal 

 sense in order to have the two surfaces directly superimposed (fig. 7).. 



