266 THE POPULAR SCIENCE MONTHLY 



cerned. There is, furthermore, a considerable seasonal migration 

 across the Atlantic. Thousands of Italians come to the United States 

 in the spring, to work during the warmer months, when farm and out- 

 door laborers are in demand, and return to the milder climate of Italy 

 for the winter. Similarly, there is a seasonal migration, also chiefly of 

 Italians, to Argentina at harvest time. 



In connection with these larger migrations, there is an interesting 

 tendency westward, observable not only in the westward " course of 

 empire," but in the advantages enjoyed, in the belt of prevailing west- 

 erly winds, by those who live in the western quarters of cities. The 

 " west ends " are usually the most fashionable and the newest sections 

 of these cities, while the quarters to leeward, the "east sides" and 

 " east ends," are inhabited by the poorer classes. 



The Continents and the Temperate Zones. — So far as the conti- 

 nents are concerned, in their relation to the zones, Europe is well situ- 

 ated, being almost altogether in the temperate zone, and open to the 

 ocean on the west, so that nearly all parts of it are well watered. 



Asia is an overgrown continent. Much of it is in the temperate 

 zone, it is true, but the interior is so far from the sea that the climate 

 is severe, and the rainfall very deficient. This condition of hopeless 

 aridity is depressing in the extreme, and this region is prevented from 

 becoming thickly populated, or important, on that account. 



Most of Africa is within the tropics. Its plateaus will furnish 

 areas not wholly unfavorable for white settlement. The southern part 

 of Africa is just within the marginal subtropical belt of the south tem- 

 perate zone. The same is true of Australia. Most of the latter con- 

 tinent is a trade-wind desert, and therefore hopelessly arid. 



South America is, unfortunately for white occupation, widest 

 within the tropics, while its southern portion tapers off into the tem- 

 perate zone. As a future home for the white race, it offers much less 

 attractive possibilities than it would were the continent narrow within 

 the tropics, and broad to the south. Its western portion is peculiar in 

 having the tempering influence of high plateaus in the interior, and of 

 a cool ocean current along the coast. 



North America is widest in the temperate zone. This is one of its 

 greatest assets. It suffers from the extreme cold of its winters in the 

 north, and from the rain-shadow effect of its western mountains, which 

 gives the interior basin and part of the western plains deficient pre- 

 cipitation. The interior of North America has more favorable rainfall 

 conditions than Asia, because our continent is narrower. The eastern 

 portion of North America is freely open to the Atlantic and the Gulf 

 of Mexico, and this condition is much better than is the case in Asia. 

 Most of the United States is wonderfully adapted, climatically, to 

 serve as the home of a dense population. 



The Life of Man in the Polar Zones: a Minimum of Life. — In the 



