JOHN WESLEY POWELL 1 23 



differently to similar stimuli ; and he soon perceived that the 

 thought of the lowly man of woodland or water side is more 

 dependent on surroundings than is that of the vigorous scion of 

 a race trained to conquest over nature through many genera- 

 tions. Thus he came to realize that relation between mind 

 and environment which led to his most comprehensive and im- 

 portant generalization, /. c.^ that of the great stages of human 

 progress. These stages may be defined in various ways ; by 

 progress in social organization or law, by progress in industries, 

 by progress in language, by progress in the arts, or by progress 

 in philosophies ; yet in the last analysis they express grades of 

 intelligence, and hence correspond closely howsoever defined. 

 As originally outlined the stages are (i) savagery, in which the 

 social unit is the clan, and the organization is based on kinship 

 traced on the maternal line; (2) barbarism, in which the units 

 are the gens and tribe, while the organization is based on kin- 

 ship traced in the paternal line ; and (3) civilization, in which 

 the unit is first the city and later the nation, and in which the 

 organization is territorial — to which may be added (4) enlight- 

 enment, in which the units are the individual and the state, 

 while the law rests on equality of individual rights. Mankind 

 may be classified in terms of these developmental stages no less 

 definitely than by skin color and other physical attributes ; and 

 there is every promise that the classification of the world's peo- 

 ples by culture grade will become increasingly important as 

 inter-racial contacts multiply. It was in these broader gener- 

 alizations that Powell especially profited by the genius of such 

 great predecessors of the earlier epochs as Aristotle and Bacon. 



When a knowledge maker has given form and substance to 

 a great science ; when he has shaped an epoch in the develop- 

 ment of human knowledge ; when by the vigor and extent of 

 his work he has raised himself to the first place among the 

 scientists of his generation ; and when, withal, he has con- 

 stantly fostered every scientific activity of his land, and has 

 performed public administrative duties in science of unequaled 

 magnitude, his work is not easily summarized within the space 

 of a few minutes. The published details of Powell's work fill 



