As the mineral resources of older countries become exhausted it is altogether likely that industrial supremacy will pass with them. New countries, which today have unexplored possibilities in coal and iron, will then have their turn in industrial prominence. Who knows where the balance of industrial power will be lodged a hundred years hence. China, for aught we know, may be the chief manufacturing country of the world in the twenty-first century. If we knew exactly how long the natural resources of Europe and America will hold out, and if we knew also just how much mineral wealth there is in the Far East, we could predict these things with reasonable certainty. [Sidenote: How geography will influence the future progress of America.] Certain it is, at any rate, that the past history of America has been determined, in no small degree, by geographical conditions. The same factors are likely to influence the future. The country is becoming less agricultural, less dependent upon the soil. As it becomes more industrial our dependence upon its other natural resources, upon coal, iron, oil, copper, timber, and water power must necessarily increase. The commerce of the country keeps on growing, and with this growth the reliance of the nation upon its harbors and waterways will inevitably become greater. As population expands there will be a heavier demand upon the food supply and the time will doubtless come when the United States will have no food for export. Indeed the day may arrive when agricultural products will have to be imported from outside. All this points to the need for emphasis upon conservation. It means that we should avoid all wastage of natural resources. The fertility of the soil should be preserved by scientific methods of agriculture. The mineral wealth of the country should be utilized in such a way as to give the greatest advantage over the longest period of time. We must reforest our unused lands. Harbors and waterways should be developed to aid commerce. If these things are done, America can face the future with confidence. General References GREGORY, KELLER, and BISHOP, _Physical and Commercial Geography of the United States_, pp. 252-350; A. P. BRIGHAM, _Geographic Influences in American History_, especially pp. 70-104; E. C. SEMPLE, _Influences of Geographic Environment_, pp. 51-71; O. W. PRICE, _The Land We Live In_, pp. 99-138; N. S. SHALER, _Man and the Earth_, pp. 1-19; C. R. VAN HISE, _The Conservation of Natural Resources in the United States_, especially pp. 263-306; T. N. CARVER, _Sociology and Social Progress_, pp. 174-270 (The Influence Exerted by Physical Laws over the Organization of Society and the Character of Individuals, by T. H. BUCKLE); _Ibid._, _Principles of National Economy_, pp. 3-14; 123-152; C. A. BEARD, _American Government and Politics_, pp. 405-416; _Ibid._, _Readings in American Government and Politics_, pp. 368-374;