ix.] THE ARTISTIC FACULTY. 163 



to become suddenly paramount, so that Grade 99° 

 paired in an instant with Grade 1°; next 98° with 2°; 

 and so on in order, until the languid desires of 49° and 

 51° were satisfied last of all. Then every one of 

 the Mid-Parents would be of . precisely the same stature 

 P. Consequently their Q would be zero ; and that of 

 the system of the Mid- Co -Fraternities would be zero 

 also ; hence the Q of the next generation would con- 

 tract to the Q of a Co-Fraternity, that is to 1*5 inch. 



Whatever might be the character or strength of the 

 bias in marriage selection, so long as it remains constant 

 the Q of the population would tend to become con- 

 stant also, and the statistical resemblance between 

 successive generations of the future Population would 

 be ensured. The stability of the balance between the 

 opposed tendencies of Regression and of Co-Fraternal 

 expansion is due to the Regression increasing with the 

 Deviation. Its effect is like that of a spring acting 

 against a weight ; the spring stretches until its gradually 

 increasing resilient force balances the steady pull of the 

 weight, then the two forces of spring and weight are 

 in stable equilibrium. For, if the weight be lifted by the 

 hand, it will obviously fall down again as soon as the 

 hand is withdrawn ; or again, if it be depressed by the 

 hand, the resilience of the spring will become increased, 

 and the weight will rise up again when it is left free to 

 do so. 



m 2 



