JOSEPH KRAFKA, JR. 



423 



The Qio values, when calculated directly for intervals of 10°, closely 

 approximate the theoretical demands of van't Hoff's law (Tables 

 VIII and IX). 



When the Qio values are calculated from the Qi,Q2,etc., an interest- 

 ing fact is discovered. In Tables X and XI, I have calculated the 

 Qio values from the formula Qio = (Qt^ -12)17-72 • The values of Qio 

 vary from 5.69 to 1.60. The lower values are at the median tempera- 

 tures while the higher ones are at the extremes. This is not the char- 

 acteristic variation in Qio for chemical reactions. The values consist- 

 ently decrease in the latter with increase in temperature. 



TABLE VIII. 



Qio Calculated Directly for Ten Degree Interval. Ultra-Bar Females. 



TABLE IX. 

 Qio Calculated Directly for Ten Degree Interval. Low Selected Bar Females. 



In Fig. 8 the curve for the facet numbers in the Ultra-bar females is 

 superimposed on a theoretical van't Hoff curve. In the latter the 

 rate at 10°C. is arbitrarily taken as 10; from which at 20°C. it becomes 

 20 and at 30°C. it is 40. Intermediate values are interpolated. The 

 experimental curve is fitted to the other by taking the value of "fa- 

 cets" at 20°C. as 20 and then applying the Qtj-t, as given in Table 

 X. It is plainly evident that the experimental curve for the effect of 

 temperature upon facet number is something more than a chance ap- 

 proximation of the theoretical van't Hoff curve. 



