method woxild be to find some plant measurement or to evaluate 

 some plant process dependent on external conditions and at 

 the same time not subject to extreme variations lue to inter- 

 nal changes in the plants. Or, a measurement or Drocess might 

 be found whose variation due to internal changes woiild follow 

 some simple, easily determined relation. The fact was noted 

 above that the graphs representing the average seasonal stem 

 height values for two and four weeks of growth were parallel 

 in general. This measurement may, therefore, have the quali- 

 fications noted above. That an approximately constant rela- 

 tion exists between ^s^ t-o and four-week stem height may be 

 shown by dividing the two-week seasonal averages for each sta- 

 tion by the four-week seasonal average. We find that tMs gives 

 values of the ratio as shown below; 



Oakland - l.Pl 



Ghewsville 1.16 



Monrovia 1.18 



College 1.19 



Baltimore 1.20 



Darlington 1.07 



Coleman 1.20 



Easton 1.27 



Princess Anne 1.15 



The average of these ratios is 1.18. If, therefore, the stem 

 height of the soy-bean, grown as a standard plant, be used as 

 a measure of the climatic complex and the measurement be express- 

 ed as relative aver ge daily increments as in this study, the 

 two-week readings may be corrected to the four-week readings 

 (considering these as the standard) by dividing each two-week 

 reading by the constant 1.18. Evidnece which cannot be given 

 her'= shows that the rate of photosynthesis also, is dependent 



