Potatoes.—Potatoes, Fig. 105, are a cyclonic crop even more strikingly than wheat. Practically none are raised outside the cy clonic regions. Western Europe seems almost tc be one great potato patch. We think that we raise a great many potatoes, but Europe raises 90 per cent of the world crop. In northern Europe this crop occupies much the same pre-eminent position as the rice crop in the Orient and corn in the corn belt of the United States. We speak of Irish potatoes because the damp cool climate causes them to be the chief food in Ireland. The Irish crop, however, is a small matter compared with that of Germany, which is four times as large as that of the whole United States. This explains how it happened that during the Great War the saving of the waste caused by peeling raw potatoes was an important means of enabling the Germans to get food enough when their outside supplies were cut off. It is strange that the potato which originated in the tropical highlands of America should now be raised chiefly in the cyclonic regions of Europe.
Corn.—The map of corn, Fig. 106, shows an interesting contrast to that of potatoes. The two crops both grow most abundantly in the United States and Europe, but not in the same places. Corn on the whole grows somewhat equatorward of potatoes. It needs hot, sunny weather with abundant showers. In the United States these conditions occur on the southeastern flank of the cyclonic belt from Iowa, Illinois, and Ohio southeastward. In Europe the corn belt lies similarly on the southeastern flank of the storm belt, so that it falls in Italy, Austria, and Roumania. In South America, again, the main corn area in Argentine lies in a similar position, which means that it is located on the northeast or equatorward margin of the storm belt. Corn likewise grows outside of the cyclonic belt in places like Mexico, and in Egypt and India where it is irrigated. Three-fourths of the world's crop, however, grows in the United States, while the production in other American countries, especially Mexico and Argentine, equals that of the rest of the world. In this case, quite unlike the potato, a plant which is native to America is still cultivated chiefly in this continent. Nevertheless, although corn originated in tropical regions and was mainly cultivated there for many centuries, the superior energy of the people of the cyclonic belt has now caused it to be chiefly a crop of cyclonic areas. Corn, potatoes, and wheat all illustrate the striking fact that if a plant is unusually good for food the people of cyclonic regions take it in hand and not only im prove it, but produce new varieties which will grow where these people want them. That is one great reason why so large a number of the
world's chief food crops grow in cyclonic regions.
Oats, Rye, and Barley.—Of the three cereals which stand next to corn in importance, both oats and barley are naturally products of the cyclonic regions of Europe where they now chiefly occur. Rye came originally from the mountainous parts of the subtropical region around the Mediterranean and in western Asia. Oats, Fig. 108, grow in much the same cyclonic regions as potatoes, but are more widely distributed. They are equally good for men and horses, but unfor tunately are so bulky that they cannot bear the cost of long trans portation. Hence they are largely consumed close to where they grow and are used for horses more then for men. Rye grows in much the same places as potatoes and oats, that is, farther north than wheat, but within the limits of the cyclonic regions. About 96 per cent of • the world's entire crop is raised in Europe, especially Belgium, Ger many, and central Russia. It occupies the poorest soils of cyclonic regions as well as the poorest climates, and is eaten by the poorest people. Barley grows in essentially the same places as wheat, but has a shorter growing season and can endure greater aridity and lower temperature. Hence barley increases in relative importance on the edges of the wheat regions, such as North Africa and Turkey, where the climate is dry, and in Great Britain and Scandinavia, where the climate is cool.
Swine.—Swine, Fig. 107, illustrate the way in which the people of the cyclonic areas take animals, as well as plants, from other parts of the world and make them much more useful than in their native homes. Wild pigs of one kind or another are found in most parts of Europe, Asia, and Africa, while their near relatives, the peccaries, occur from New Mexico southward to Patagonia. The wild pigs find it easiest to get a living in the warmer regions, and domestic pigs can be kept in such regions with the minimum amount of work. Yet to-day the central United States, where there have been no wild pigs for millions of years, has more swine in proportion to the popu lation than any country except Denmark. Other cyclonic coun tries like Germany, Austria, Hungary, and Argentina also have a relatively large number. Where tropical or Oriental countries have many pigs, as in Venezuela, Colombia, and China, it generally means that they have very few other domestic animals, and that they can keep the pigs with almost no trouble. In Mohammedan countries, on the contrary, the use of swine for food is forbidden by religion, and hence as the map shows, the familiar pig stye is absent in those lands.