71. Frost breaks cold weather, the water freezes in the cracks of rocks and breaks them open. Freezing water has force enough to burst pitchers, bottles, and even iron pipes. Perhaps you have seen such a thing happen. The rocks broken by the force of the freezing water will, in course of time, become soil.
72. Top soil and under see the rocks have many enemies that are always attacking them and slowing turning them into the earth that is needed for grow ing food. We find that this earth is finest near the top, because the roots, the frost, and the rain work most near the surface of the earth. Sometimes you can see the several kinds of soil in a cut beside a road or in a place where a cellar is being dug. Beneath the fine top soil comes a coarser under layer; next are the small pieces of stone mixed with earth, then larger stones, and finally the solid rock with cracks in it (Figs. 74, 75). All of the soil you ever saw was once hard rock.
In mountains and hilly countries such as New England and the Appalachian Mountains, the running water often carries the little soil particles away almost as fast as they are formed. Only a thin layer of soil is left on the hills, but the water carries the earth into the valleys, which often have fine deep soil. In the North Central States most of the land is so level that the soil is not carried away. The rock is far down below a thick layer of soft, fine earth. All this is good for the corn grower.
73. Other crops on the corn farm.— The farmer who grows corn in the Central States grows other crops also. He has horses to help him work, and often he has cattle and pigs as well. He has a pasture field where his animals may eat grass in summer, and another field that grows hay (Fig. 78). Hay is grass that has been cut
and dried in the sunshine. It is then put into big stacks, or into barns, so that it will keep for winter use. Nearly always there are barns and other buildings near a farmer's house.
74. Other places grow corn.—Let us leave the North Central States and see where else corn grows. Remember, corn likes rich soil, showers, sunshine and warm weather. On the corn map (Fig. 79) you will notice that the states in the south and east grow corn, but less than is grown in the Central States.
The world corn map (Fig. 80) shows that there is a corn region in South America and one in Europe. But both together are not nearly so large as the one in the United States. What South American country grows corn? The only European country that has much corn to export is Rumania (Fig. 315). Steamships from England and Italy go up the Danube river and bring away loads of Rumanian corn. Can you name and point out ports to which they might take the corn (Fig. 315), and the bodies of water through which they might sail? The Rumanian corn grower has a hard time, for corn does not grow so well in his country as in ours. One year the Ruman ians may have a good crop. The next year may be so dry that the Rumanian corn grower gets but a quarter of a crop. That year he has but little money. If farmers have no money to spend, they cannot buy things from the stores and factories, and therefore business is poor in the cities. In the North Central States, with their many summer showers, the corn growers have more corn and more money than they do in Rumania. Do you see why many Rumanians want to come to the United States to live?