CHAPTER IV. 



SCHEMES OF DISTRIBUTION AND OF FREQUENCY. 



Fraternities and Populations to be treated as Units. Schemes of Distribu- 

 tion and their Grades. The Shape of Schemes is independent of the 

 number of observations. Data for Eighteen Schemes. Application 

 of the method of Schemes to inexact Measures. Schemes of Fre- 

 quency. 



Fraternities and Populations to be Treated as Units. 

 The science of heredity is concerned with Fraternities 

 and large Populations rather than with individuals, and 

 must treat them as units. A compendious method is 

 therefore requisite by which we may express the dis- 

 tribution of each faculty among the members of any 

 large group, whether it be a Fraternity or an entire 

 Population. 



The knowledge of an average value is a meagre piece 

 of information. How little is conveyed by the bald 

 statement that the average income of English families is 

 100/. a year, compared with what we should learn if we 

 were told how English incomes were distributed ; what 

 proportion of our countrymen had just and only just 

 enough means to ward off starvation, and what were the 



D 2 



