discharge of the German rivers is not above one fourth that of the Mississippi system, as contrasted with one fifth for Britain. Greater ruggedness of surface marks a part of the German territory, but on the other hand, a very large part of the drainage area of the chief streams lies in the North German plain at altitudes under 600 feet, as unfavorable for power development as they have been favorable to river navigation. At the best, therefore, the German streams could hardly be counted on for more than 10,000,000 horse power, or again less than the amount of mechanical energy actually employed at present. The position of Germany offers little prospect for the use of power from the sea on any such important scale as seems feasible in Britain, and other likely sources of water power do not appear to afford the necessary relief. The future of Germany seems, therefore, to present a case in which the question of power and a stage of evolution arising from its use is likely to involve readjustments of a far-reaching character.
The contrast of these two examples, Britain and Germany, may serve to illustrate the extent to which permanent natural sources of mechanical power are factors for national strength, second in importance only to the capacity of the soil to produce food, since under favorable circumstances both afford a solid basis for large national development. It must be recognized, however, that in assuming a logical and permanent stage of evolution based on the possession of power alone, it is necessary to take into account the likelihood of there always being some areas so endowed as to produce surplus necessities of life* while they, or other areas, are unable from their own surroundings to satisfy their needs for the products of power.
Mineral Wealth.—The part played by one sort of mineral supply, in national development, has been indicated in the discussion of coal as a source of energy. With respect to the products of the mines in general and particularly if the term be liberally interpreted, to include all inorganic products of the earth, it may be said that they as a group represent one of the most important of physical factors in the modern progress of nations. Leaving coal entirely aside, it still remains true that the tremendous development of every phase of modern industry, from the cultivation of the soil to the most complex manufacturing process, has become possible only through the constantly increasing employment of mineral products. In fact, the critical difference between the nations of to-day and those of the past is found in the present dependence on materials won from the earth's crust; and it might almost be said that the nations rank to-day and will in the future continue to rank in direct proportion to the wealth of their mineral resources.
The question needs, however, to be considered carefully, since some