THE AMERICAN MIGRATION. 345 



and as we depart, either to the north or south, from the latitude assumed as the 

 origin of the human race in Asia, we meet with a lower and lower type until at 

 the north we encounter the Esquimaux, and at the south the Bosjesman and the 

 Tierra Fuogian. The derivation of these varieties from the original stock is 

 philosophically explained on the principle of the variety in the offspring of the 

 same parents, and the better adaptation and consequent chance of life, of some of 

 these to the new conditions of existence in a more northern or southern latitude. 

 Furthermore, as the author has shown, the migrations on the American con- 

 tinents have principally been from north to south, and it is an interesting fact, 

 fully confirmed by tlie observations of the explorers of the route for the Russian 

 American telegraph, that the waters of Bchring's Straits are frozen over prob- 

 ably every year as late as April, and that intercourse, at present, is constant 

 by means of canoes in summer between the Asiatic and American sides. ^ As 

 another fact relating to the same question, we may state that, while the Asiatic 

 projection near Bebring Straits is almost a sterile rocky waste, the opposite coast 

 presents a much more inviting appearance, abounding in trees and shrubs. 

 Moreover, the climate, when we pass southward of the peninsula of Alaska, is of 

 a genial character, the temperature continuing nearly the same as far dowii as 

 Oregon. The mildness of this temperature, and the descent of the isothermal line, 

 or that of equal temperature along the coast, are due to the great current called 

 the gulf stream of the Pacific, which carries the warm Avater of the equator along, 

 the eastern coast of Asia, thence across to the opposite coast of America, and along 

 the latter on its return to the equator. The action of this current, which does not 

 appear to have been considered by the ethnologist, raust have had much influence 

 in inducing and determining the course of the migrations. We may add to the 

 foregoing that the present inhabitants of the countries contiguous to Behring's 

 Straits on the two sides, in manners, customs, and physical appearance, are almost 

 identical. J- H.j 



