1160 



THE LIGHT FACTOR. III. COLOR 



CHAP. 30 



The same picture (fig. 30.6A) should be obtained also for partially absorb- 

 ing systems, if P is plotted against the absorbed (rather than against the 

 incident) intensity. If Nn^ (incident) is used as the independent variable 

 and the absorption is comparatively weak, the resulting picture must be 

 that shown in figure 30.6B. 



If the monochromatic light curves are plotted against light energy (I, 

 or A) instead of number of quanta, Nh;,, the relationships become unneces- 

 sarily obscured {of. fig. 30.6C). (Some investigators, e. g., Montfort, have 



12345 123456 m.c. 



/(in klux for white light; in "energetic meter candles' for colored light) 



Fig. 30.7. Light curves of Chlorella in liglit of different color. (A) Green vs. red light 

 (equal energy flux); "dense" suspension (11 X 10^ cells per cc). (B) Red vs. white 

 light (energy flux in klux for white light, in "energetic meter candles" for red light, cf. 

 chapter 29, p. 1098). "Thin" suspension, 2 X 10" cells per cc. 



used rate measurements in monochromatic light to raise the question 

 whether ])hotosyn thesis "is a quantum process at all" ; a question no photo- 

 cliemi.st would ever ask. 



The available experimental material to which the above predictions can 

 be applied is very scarce. It is desirable that the precise methods of rate 

 determination, applied as yet almost exclusively to the quantum yield 

 determinations in weak light, should be extended to kinetic studies in 

 strong monochromatic light. 



As examples of the few available experimental monochromatic light 



