If at the proper season of the year one goes from Pittsburg to Chicago via Columbus and Indianapolis, he will see great fields of winter wheat and a considerable number of permanent pastures. From Chicago to Omaha he will see only occasionally a field of wheat and scarcely any permanent pasture. Oats have taken the place of wheat. In parts of Eastern Kansas and Oklahoma the predominant crop is winter wheat. Throughout the whole region from Pittsburg to Topeka, Kansas, the characteristic crop is maize or Indian corn. Between St. Paul and Fargo, the main crops are spring wheat and oats. One may travel from Winnipeg, Manitoba, to Calgary, Alberta, a distance of over one thousand miles without seeing a field of maize. In some portions the main crop is wheat, in others it is oats. These are illustrations of the crop adaptation over large areas, which has come about unconsciously, as has most crop adaptation. In other parts of the United States are to be found even more striking examples of crop adaptation, although the areas are much smaller, as in the case of tobacco, potatoes, celery, onions, apples, peaches and other fruits. Regions containing residual soils are more variable in crop adaptation than drift soils and require more careful watchfulness on the part of those who may wish to buy land. As previously stated, advantages, if known, must usually be paid for. It comes about, therefore, that if a region or a farm is adapted to the raising of a certain crop which is more profitable than the average, such as maize, tobacco, alfalfa, celery, apples or peaches, this land will, other things being equal, command a higher price than land which does not possess this characteristic. There is an underlying economic principle which the man who goes out to choose a farm should clearly understand. The principle has been stated by Fairchild as follows: "The normal value of products capable of indefinite multiplication tends always toward the value of least costly. On the other hand, if any production cannot be largely extended, so that the supply barely meets the requirements of the purchasers, the tendency of normal values is toward the cost of the most costly part of the product required to meet wants." This principle explains why land especially adapted to raising maize is higher priced than land primarily adapted to raising wheat. Maize which enters into commerce is raised almost exclusively in ten states of the United States. Wheat is harvested practically every month of every year in different parts of the world. The young farmer should consider, therefore, whether he is undertaking to raise crops in which there is unlimited competition, or whether soil or other conditions cause the output to be relatively limited. CHAPTER VI SIZE OF FARM