vir.] DISCUSSION OF THE DATA OF STATURE. 115 



clearly, after making many attempts. Their curvatures 

 are so delicate and peculiar that the eye can hardly 

 appreciate them even in a model, without turning it 

 about in different lights and aspects. A plaster model 

 of an intermediate form was exhibited at the Royal 

 Society by Mr. J. D. H. Dickson, when my paper on 

 Hereditary Stature was read, together with his solutions 

 of the problems that are given in the Appendix. I also 

 exhibited arrangements of files and ranks that were 

 made of pasteboard. Mr. Dixon mentioned that the 

 mathematical properties of a Surface of Frequency 

 showed that no strictly straight line could be drawn 

 upon it. 



Successive Generations of a People. — We are far too 

 apt to regard common events as matters of course, that 

 require no explanation, whereas they may be problems 

 of much interest and of some difficulty, and still await 

 solution. 



Why is it, when we compare two large groups of 

 persons selected at random from the same race, but 

 belonging to different generations, that they are usually 

 found to be closely alike ? There may be some 

 small statistical dissimilarity due to well understood 

 differences in the general conditions of their lives, but 

 with this I am not concerned. The present question 

 is as to the origin of that statistical resemblance between 

 successive generations which is due to the strict pro- 

 cesses of heredity, and which is commonly observed in 

 all forms of life. 



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