vni.] DISCUSSION OF THE DATA OF EYE COLOUR. 147 



tend to neutralise each other. In Table 20 I have 

 separately classified on the same system all the families, 

 78 in number, that consist of six or more children. 

 These data enable us to test the trustworthiness of the 

 law as applied to individual families. It will be 

 seen from my way of discussing them, that smaller 

 fraternities than these could not be advantageously 

 dealt with. 



It will be noticed that I have not printed the number 

 of dark-eyed children in either of these tables. They 

 are implicitly given, and are instantly to be found by 

 subtracting the number of light-eyed children from 

 the total number of children. Nothing would have 

 been gained by their insertion, while compactness would 

 have been sacrificed. 



The entries in the tables are classified, as I said, 

 according to the various combinations of light, hazel, 

 and dark Eye-colours in the Parents and Grand-Parents. 

 There are six different possible combinations among the 

 two Parents, and 15 among the four Grand-Parents, 

 making 6 x 15, or 90 possible combinations altogether. 

 The number of observations are of course by no means 

 evenly distributed among the classes. I have no returns 

 at all under more than half of them, while the entries 

 of two light-eyed Parents and four light-eyed Grand- 

 Parents are proportionately very numerous. 



The question of marriage selection in respect to 

 Eye-colour, has been already discussed briefly in p, 86. 

 It is a less simple statistical question than at a first sight 

 it may appear to be, so I will not discuss it farther. 



l 2 



