It is not simply because an old habitat becomes too crowded, although it is true that there is a kind of inertia, consisting of habit, love of home, fear of the unknown, differences of language, and so on, which keeps population settled until stress is felt. There is a great economic advantage in spreading such population as there is over all the land there is, although they cover it but thinly. This economic advantage is accompanied by a great social disadvantage. In a scattered population the social organization is low and the social activities are weak. Such institutions as churches, schools, libraries, and museums, which flourish only in great centers of population, are feeble or non-existent. The spread of population over a great area of land, however, puts the first absolute necessities of existence within easy reach of those who have nothing but muscular strength at their disposal. The internal movement of population in the United States has illustrated all this most obviously. The social inertia which has been mentioned is less effective in our old states to keep people from going to the new states than it is in Europe to prevent emigration to the new countries. Hence we find that Iowa has been largely settled by emigrants from Illinois, and Montana is now being settled by emigrants from Iowa. This is the phenomenon of earth hunger, the apparently insatiable desire to get more land; and the reason for it lies in the facts which have been mentioned. With more land, there are higher wages, because no one will work for wages which are convertible into less goods than the laborer could get out of the land when used in the most lavish and wasteful manner. With more land, the manual unskilled laborer is raised in comparison with the skilled and educated laborer, that is, the masses are raised in comparison with the classes. When there is plenty of land, the penalties
