THE PURE LINE 



99 



therefore Gallon reckoned a "midparent" in each 

 case, according to the formula 



1.00 $ + 1.08 $ 



2 



in order to represent the double parental generation 

 by a single number for the purpose of easy compari- 

 son with the filial generation. 



63 



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 



