6 THE POPULAR SCIENCE MONTHLY. 



believe, in accord with the facts. The polar tribes are known to be 

 yellow. Among them, more frequently than elsewhere, according to 

 Quatrefages, occur cases of dry, rough skins. This I take to be a re- 

 sult of the thickness of the cuticle, just as, on the older parts of a tree, 

 the roughness of the bark is a consequence of its thickness. 



It is well known that the climate of Europe, where white men most 

 abound, is more influenced by the sea than that of any other conti- 

 nent. With the inconsiderable exception of the Caspian and Arctic 

 regions, where yellow men occur, it may all be said to be kept moist 

 by breezes from warm tracts of water. The fairest members of the 

 human family are found in the humid lands about the North and Bal- 

 tic Seas, where the influence of the Gulf Stream is most felt, and where 

 a temperate climate extends farther from the equator than elsewhere 

 on the face of the globe. When we proceed eastward from the Baltic, 

 the complexions gradually darken as the increasing range of the ther- 

 mometer indicates increasing dryness. Moscow, Kazan, and Tomsk are 

 all near the fifty-sixth parallel of north latitude. The difference be- 

 tween the temperatures of the warmest and coldest months at these 

 places is respectively 53, 61, and 69 Fahr. At Moscow, the popula- 

 tion consists of fair- and dark-haired whites. About Kazan, though 

 there are still fair and dark whites, there are also yellow men. At 

 Tomsk the entire native population belong to the yellow race. 



That the climate of the whole of Asia, from the Hindoo-Koosh 

 and Himalaya Mountains northward, may be considered dry, is shown 

 by the extensive deserts and the great range of temperature in the 

 countries where sufficient rain falls to render agriculture possible. 

 For instance, in China and Japan the range of the thermometer is 

 somewhat greater than in corresponding latitudes in the eastern United 

 States. The entire population of this vast area is yellow, with insig- 

 nificant exceptions on its western border. 



The greater part of North America corresponds in climate with 

 central and eastern Asia. But the meteorological phenomena of the 

 coast of British Columbia and Alaska are similar to those of the 

 northwest of Europe. Warm winds from the Pacific keep the tem- 

 perature high and the air moist ; but, owing to the configuration 

 of the coast and the direction of the mountain-ranges, their influence 

 does not extend far inland. The immense difference between the cli- 

 matic conditions of the eastern and western coasts of America may 

 be illustrated by comparing the temperatures of Sitka (57 3' N. L.) 

 and Quebec (46 49' N. L.). Though the latter is more than ten 

 degrees farther south, its mean annual temperature is two degrees less, 

 and, while the difference between the means of the warmest and 

 coldest months is fifty-seven degrees at Quebec, it is only twenty-five 

 at Sitka. 



It is a fact which strikingly corroborates the theory advanced in 

 this paper, that it is precisely in the northwestern part of this conti- 



