vin.] DISCUSSION OF THE DATA OF EYE COLOUR. 145
about only two-thirds of the grandparents, but this will suffice for our purpose. The results are given in Table 16.
It will be observed that the distribution of eye-colour among the grandparents of the hazel-eyed families is nearly -identical with that' among `the population at large. But among the parents there is a notable difference ; they have a decidedly larger percentage of light eye-colour and a slightly smaller proportion of dark, while the hazel element is nearly doubled. A similar change is superadded in the children. The total result in passing from generations III. to I., is that the percentage of the light eyes is diminished from 60 or 61, to 45, therefore by one quarter of its original amount, and that the percentage of the dark eyes is diminished from 26 or 27 to 23, that is by about oneeighth of its original amount, the hazel element in either case absorbing the difference. It follows that the chance of a light-eyed parent having hazel offspring, is about twice as great as that of a dark-eyed parent. Consequently, since hazel is twice as likely to be met with in any given light-eyed family as in a given dark-eyed one, we may look upon two-thirds of the hazel eyes as being fundamentally light, and onethird of them as fundamentally dark. I shall allot them rateably in that proportion between light and dark, as nearly as may be without using fractions, and so get rid of them. M. Alphonse de Candolle 1 has
1 11WO ditg de la Couleur des Yeux dans 1'Espece humaine," par A1. Alphonse de Candolle. " Arch. Se. Phys. et Nat. Geneva," Aug. 1884, 3rd period. vol. ,ii. p. 97.