1920] 



SNOW— DIAPHRAGMS 



3° 3 



ment 



thermostats were kindly loaned by the Chemistry 

 and were regulated by Captain de Klotinski. Tl 



i vessel was kept within a degr 

 remainder of the experiment 



the 



the temperature 

 e rest of the time 



higher 

 C. for two weeks, 



C. In 

 stream of 



1 



3 first two 

 C. The temperature 



in this vessel was not quite so constant as in the high 

 thermostat, because of the varying water pressure 

 of plants was allowed to grow without temperature c 



A third set 

 trol. When 



the change to air was made, the pots were transferred to beakers 



TABLE V 



BETWEEN RATE OF GROWTH AND DI! 



Scirpus validus 



v^-% 



DIAPHRAGMS IN 



Change 



Culm no. 



Rate 



Water to air 



Air to water 



Low to high temperature 



High to low temperature. 



E 2 

 \ B 4 



fAA 3 

 \DD 7 



AA3 



Decreased 

 Decreased 

 Decreased 



Increased 

 Increased 



Increased 



Increased 

 Decreased 

 Decreased 

 Decreased 



Distance 



Increased 

 Increased 

 Increased 



Increased 

 Increased 



Decreased 



Decreased 

 Increased 

 Increased 

 Increased 



sunken to the rim in the water of the thermostats. Water was 

 poured into the beakers to within an inch of the surface of the 



soil. 



allowing 



culms to project between them, and the crack was plugged with 

 cotton wool. Close observation showed the temperature in the 

 beakers to be practically the same as that of the water outside. 

 Measurements were taken every 24 hours, and the rate of growth 

 given for a region was usually the average for several days, thus 

 eliminating the questioned stimulating effect of the change (i, 9, 



10 



14). 



the end of the experiment longitudinal 



sections were made in the regions grown under the 



tions. 



made 



/ 



