MEASUREMENTS OF RELATIONSHIPS 45 



when they were male brothers' first-rib lengths, and could not prop- 

 erly be so interpreted if they were related body-strengths and earn- 

 ings in dollars. For we have evidence from cephalic index, stature 

 and the like to justify some expectation of linear correlation for 

 fraternal relationships in features of anatomy, whereas what evi- 

 dence we have concerning the relationship between body-strength 

 and earning capacity in individuals goes to show that it is far less 

 close for those of high earning capacity than for those of very low 

 earning capacity. 



