402 



Mr. F. Galton. 



[May 27, 



May 27, 1886. 



Professor STOKES, D.C.L., President, in the Chair. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



The following Papers were read : — 



I. " Family Likeness in Eye-colour." By FRANCIS Galton, 

 F.R.S. Received May 10, 1886. 



My inqniry into Family Likeness in Stature (ante, p. 42) enabled 

 me to define, in respect to that particular quality, the relation in 

 which each man's peculiarity stands to those of each of his ancestors. 

 The object of the present memoir is to verify that relation with 

 respect to another quality, namely, eye-colour. 



Speaking of heritage, independently of individual variation, and 

 supposing female characteristics to be transmuted to their male equi- 

 valents, I showed (1) that the possession of each unit of peculiarity 

 in a man [that is of difference from the average of his race] when 

 the man's ancestry is unknown, implies the existence on an average 

 of just one-third of a unit of that peculiarity in his " mid-parent," 

 and, consequently, in each of his parents; also just one-third of a 

 unit in each of his children ; (2) that each unit of peculiarity in each 

 ancestor taken singly, is reduced in transmission according to the 

 following average scale : — from a parent, to \ ; from a grandparent, 

 to -Yt 5 from a great- grandparent, to -g 1 ^, and so on. 



Stature and eye- colour are not only different as qualities, but they 

 are more contrasted in hereditary behaviour than perhaps any other 

 simple qualities. Speaking broadly, parents of different statures 

 transmit a blended heritage to their children, but parents of different 

 eye-colours transmit an alternative heritage. If one parent is as 

 much taller than the average of his or her sex as the other parent is 

 shorter, the statures of their children will be distributed in much the 

 same way as those of parents who were both of medium height. But 

 if one parent has a light eye-colour and the other a dark eye-colour, 

 the children will be partly light and partly dark, and not medium 

 eye-coloured like the children of medium eye-coloured parents. The 

 blending in stature is due to its being the aggregate of the quasi- 

 independent inheritances of many separate parts, while eye-colour 



