40 BULLETIN 1339, U. S. DEPARTMENT OF AGRICULTURE 



lations have been made by including five of the weather factors. In? 

 Figure 12 the symbols are as follows: G = net gain (changes of colonjr 

 weight in the fall period), T= average temperature, Tv = temperature- 

 variation, H= average relative humidity, Hv= variation of relative- 

 humidity, 5 = hours of sunshine, L = nocturnal loss, and o = residual, 

 unknown factors. It will be noted that only 5 of the weather factors 

 are here included, although 10 were determined in the original data, 

 but to have included all 10 would have made too unwieldy a calcu- 

 lation. In order to make comparison between the spring and fall 

 periods the same variables were used in both cases. Hours of sun- 

 shine were used instead of solar radiation because this factor has a. 

 larger coefficient of correlation with net gain and because there is a. 

 high correlation between these two factors of themselves. None of 

 the nocturnal factors were included in this calculation, as being of 

 probably little value in their influence on net gain. 



For these five weather factors is obtained the diagram shown in 

 Figure 12. 



From this diagram the following simultaneous equations are- 

 evolved : 



Tot = d -\~ OVttv ~\~CTht ~\~(IThvt "T VTst 



Tqtij = CLTttv ~\~ -f" CThtv ~\~ (IThvtv ~\~ GTstv 



r aH —ar T H +br T vH +c +dr HV H +er SH 



Tgh v = (LTthv -f- OTtvhv + CVhhv + d + CTsav 



r GS =-ar TS +br T vs +cr H s + dr nv s +e 



