I38 CHAP. XVII. EFFECT OF VARIATION OF TEMPERATURE 



Repetition of the experiment lowered the critical point from 

 15 ° to 14°, and finally to 13 C, which was the lowest value 

 observed. 



Photosynthesis under Variation of Temperature 



The following results concerning the activity of photo- 

 synthesis at various temperatures may be taken as typical 



Table XIX. — Showing Variation of Photosynthesis at 

 Different Temperatures 



of about a dozen experiments with different specimens 

 carried out in winter. The light was maintained constant 

 at 1200 lux from Pointolite. 



The experiment was commenced at a temperature of 



