terials and forces. In modern times the knowledge is organized in science, and both knowledge and control are gained and promoted by institutions. In leading nations these institutions are partly voluntary associations of individuals, and partly governmental agencies. During recent decades the knowledge is not merely imparted, but measurably gained by educational institutions.
In the United States the earth beneath the surface is investigated by geological surveys, state and federal; the surface is surveyed chiefly by the Geological Survey and Land Office of the Interior Department, the Soil Bureau of the Agricultural Department and the Coast and Geodetic Survey of the Department of Commerce and Labor, with corresponding instrumentalities in some states; and the life and growth on the surface are investigated chiefly by the Forest Service, the Biological Survey and the Bureau of Entomology, so far as natural conditions are concerned, and by the Bureau of Plant Industry, the Bureau of Animal Industry and the Office of Experiment Stations, so far as artificial conditions are concerned, with related instrumentalities in several states. The air in its general aspects and the water in its forms and certain functions are investigated in the Weather Bureau; as vehicles for movement of other things they are investigated in the Geological Survey and some state institutions; in their primary relation to life and growth they are investigated chiefly in the Bureau of Soils, the Office of Experiment Stations and other branches of the Department of Agriculture, and in the Reclamation Service of the Interior Department; and in their immediate relation to life and growth they are investigated chiefly in the Forest Service, the Bureau of Plant Industry, the Bureau of Animal Industry and the Bureau of Fisheries, while the running and standing water in certain applications are considered in the Hydrographic branch of the Geological Survey, the Corps of Engineers of the War Department, the Hydrographic Office of the Navy Department and the Bureau of Corporations in the Department of Commerce and Labor. The general relations of the sun are investigated in the Naval Observatory of the Navy Department, the Coast and Geodetic Survey, the Weather Bureau and the Smithsonian Institution; the relations to the surface and its life and growth are considered in the Bureau of Soils; and the more direct relations to life and growth are considered in the Forest Service, the Bureau of Plant Industry, the Bureau of Animal Industry and other branches of the Department of Agriculture.
So far as the federal government is concerned, the four natural elements of power and prosperity are investigated or considered in themselves or in their applications chiefly in a score of bureaus in five departments, as follows:
