42 CHAP Vl. RELATION BETWEEN LIGHT AND PHOTOSYNTHESIS 



sunlight of increasing intensity, as previously explained, 

 from 0-04 S to 0-40 S. It should be mentioned here that 

 the day was dull and the sunlight comparatively feeble ; 

 as far as could be judged by the eye, it was about a quarter 

 the intensity of bright sunlight at midday. I give the results 

 in the following table : 



Table VII. — Photosynthesis under Pointolite and Sunlight 

 (C0 2 -concentration, 8 mg. per 100 c.c.) 



We note from the above data that while under Pointolite 

 of 1500 lux the photosynthesis was 318, under o- 12 S it was 



Table VIII. — Photosynthesis under Increasing Intensities of 

 Pointolite and Sunlight 



(C0 2 -concentration, 3 mg. per 100 c.c.) 



337-5. By interpolation we find that 0-12 of sunlight, on 

 this particular occasion, was physiologically equivalent to 

 about 1750 lux. 



