Page:Popular Science Monthly Volume 76.djvu/270

266. 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 outdoor 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 westerly 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 continents are concerned, in their relation to the zones, Europe is well situated, 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 temperate zone. The same is true of Australia. Most of the latter continent 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 temperate 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 precipitation. 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