552 



THE NATURE OF THE GROWTH RATE 



The period was therefore divided into two cycles, the first of which 

 ended at the 62nd day, and the second of which began at approxi- 

 mately the time the first cycle ended. Reference to Table III will 

 show the computations made. Since we are interested in rate it will 

 be proper to move our base line up to a point near that at which the 

 first cycle actually started. Actually 50 cm. were subtracted from 

 each mean in order to give a curve which would start near the inter- 



TABLE m. 



Height of Juglans nigra Trees. Comparison of Observed Values with Those Com- 



puted from the Formula log = K{t—ti). 



a—x 



section of the abscissa with the ordinate. For the first cycle the value 

 of a was taken as 32, and ^i as 23.5. Accordingly 



log 



32 -a; 



= K{t- 23.5) 



From this, the several values of K were computed and found to be 

 fairly uniform. The average value of K was taken as 0.0325, and 

 from it the values of x were computed by the above formula. The 



root-mean-square deviation 



(V!) 



from the observed values was only 



0.78 cm. It will thus be seen that the agreement between observed 

 and calculated values is good. 



