Ix.] THE ARTISTIC FACULTY. 10
to become suddenly paramount, so that Grade- 990 paired in an instant with Grade I'; 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 1'. 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 contract 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 constant 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 tkntil 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 For, if the weight be lifted by the band, it will obviously fall down again as soon as the hand is withdrawn ; or again, if it be depressed by the hand, the resilience of the spring will become increased, and the weight will rise up again when it is left free to do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.
M2
