MIGRATIONS OF RACES OF MEN CONSIDERED HISTORICALLY. 569 



England to migrate in a body and establish themselves, their dairying, 

 their flax culture, and their linen manufacture, in the rich pastures and 

 humid air of Ireland. 



2. Under the head of migrations by Dispersion I include those cases 

 in which a tribe or race, while retaining its ancient seats, overflows into 

 new lands, whether vacant or already occupied ; in the latter event 

 sometimes ejecting the original inhabitants, sometimes fusing with 

 them, sometimes dwelling among them, but remaining distinct. 



Examples are furnished by the case of the Norsemen, who found Ice- 

 land practically vacant, while in England they became easily, in Ire- 

 land and Gaul more slowly, mingled with the previous inhabitants. 

 When our own ancestors came from the Frisian coast they slew or drove 

 out the bulk of the Celtic ijopulation of Eastern Britain ; when the 

 Franks entered Gaul they became commingled with it. It is by such a 

 process of disi)ersion that the British race has spread itself out ovei- 

 North America and Australasia. In much smaller numbers the Span- 

 iards diffused themselves over southern North America, and the north- 

 ern and western parts of South America; and by a similar process the 

 Eussians have for two centuries been very slowly filling the better parts 

 of Siberia. Whether in any case of dispersion the migrating popula- 

 tion becomes fused with that which it finds, depends chiefly on the dif- 

 ference between the level of civilization of the two races. Between 

 the English settlers in North America and the imtive Indians there 

 has been hardly any mixture of blood; between the French in Canada 

 and the Indians there was a little more; between the Spaniards and the 

 less barbarous inhabitants of Mexico there has been so much that the 

 present Mexican nation is a mixed one, the native blood doubtless i)re- 

 dominating. Something however also depends on the relative num- 

 bers of the two races; and sometimes religion keeps a- dispersed people 

 from commingling with those among whom it dwells, as has hapiieued 

 in the case of the Jews, the Armenians, and the Parsees. These last 

 are a remarkable instance of an extremelj^ small nation — for there are 

 not 80,000 of them all told — who, without any political organization, 

 have, by virtue of their religion, preserved their identity for more than 

 a thousand years. Dispersion has been the most widely operative form 

 of migration in modern times which have enabled remote parts of our 

 large world, separated by broad and stormy seas, to be colonized more 

 easily than in the tiny world of ancient or medieval times was possible 

 either by land or by sea. 



3. The third form, which we may call Permeation or Assimilation, 

 is not in strictness a form of migration at all, because it may exist where 

 the number of persons changing their dwelling-place is extremely small ; 

 but it deserves to be reckoned with the other two forms because 

 it produces effects closely resembling theirs in altering the char- 

 acter of a population, I use the term Permeation to cover those 

 instances, both numerous and important, in which one race or nation 



