As the eastern states became peopled more densely, cattle grazing was forced west. The cattle pastures were broken up into fields. The prairies of Illinois and Iowa became a vast cornfield. Eastern Kansas and Nebraska were turned into corn and wheat farms. Always the cattle had to give way to the grain. At last the farmers came to a strip of country where the rainfall was not enough to make grain growing profitable. This comparatively narrow strip stretches north in an irregular area of plains from western Texas to Montana. This region grows fine grass and has become the great grazing country of the United States. Here vast herds of cattle still roam on large ranches and are cared for by cowboys. [Sidenote: =Corn-fed cattle=] East of the ranch country lies the corn belt, in which Illinois and Iowa are the leading states. Cattle fatten better on corn than on any other food, and the meat of corn-fed stock brings the best prices. The corn states have therefore taken up the raising and fattening of cattle on a tremendous scale. When western cattle leave the ranch they are generally not very heavy. Thousands of carloads are shipped into the corn country each year, there to be fattened before going to the packing houses. The Department of Agriculture, at Washington, is now taking great pains to induce the boys, especially of the South, to make experiments in corn raising. Some wonderful results have been produced, and the South is in a fair way to take to the raising of corn. [Illustration: COWBOYS DRIVING CATTLE FROM THE PRAIRIE PASTURAGE _From a photograph_] [Sidenote: =Invention of refrigerator cars=] The largest meat-packing plants are located in the corn belt at Chicago, Kansas City, Omaha, and other cities. To-day meat packing is the greatest business of Chicago and many other large cities. A generation ago it had scarcely begun. But the packers learned to can meat, to use ice for cold storage, and, most important of all, the refrigerator car was invented. By this last discovery it became possible to ship meat almost everywhere. Where before the packers had to sell their goods at home, now they have the world as a market. A steer raised on the western prairies may now be fattened for market in Illinois, slaughtered in Chicago, and served in New York, or sent to England or even to the Orient. MINES, MINING, AND MANUFACTURES [Sidenote: =Great value of coal and iron=] =231. Coal and Iron.= Next to the great farm crops, coal and iron are the most valuable products of our country. The coal that is mined in one year is worth five times as much as the gold and silver combined. Our iron mines yield as much wealth in one year as the gold mines do in three. Gold and silver are luxuries without which we could get along, but our great factories, railroads, and steamship lines could not exist without an abundance of iron and coal.