THE PURE LINE 



99 



therefore Gallon reckoned a "midparent" in each 

 case, according to the formula 



1.00 a + 1.08 $ 



in order to represent the double parental generation 

 by a single number for the purpose of easy compari- 

 son with the filial generation. 



Inches 



TO 

 69 

 68 

 67 

 66 

 65 

 64 





t 



V 



FIG. 33. Scheme to illustrate Gallon's law of regression. The circles 

 represent graded groups of parental height while the arrowpoints in- 

 dicate the average heights attained by the respective offspring. The 

 offspring of undersized parents are taller, and of oversized parents are 

 shorter than their respective parents* Based on data from Galton. 



The results of his ^measurements expressed in 

 inches are shown in the following table, in which the 



