The irrigation and dry-farming developments have a significance far beyond their value in the raising of crops: they are making the people to be conservators of water, and to have a real care for posterity. Civilization, thus far, is built on the process of waste. Materials are brought from forest, and sea, and mine, certain small parts are used, and the remainder is destroyed (page 20); more labor is wasted than is usefully productive; but what is far worse, the substance of the land is taken in unimaginable measure, and dumped wholesale into endless sewer and drainage systems. It would seem as if the human race were bent on finding a process by which it can most quickly ravish the earth and make it incapable of maintaining its teeming millions. We are rapidly threading the country with vast conduits by which the fertility of the land can flow away unhindered into the unreachable reservoirs of the seas. _The conservation of food._ The fundamental problem for the human race is to feed itself. It has been a relatively easy matter to provide food and clothing thus far, because the earth yet has a small population, and because there have always been new lands to be brought into requisition. We shall eliminate the plagues and the devastations of war, and the population of the earth will tremendously increase in the centuries to come. When the new lands have all been opened to cultivation, and when thousands of millions of human beings occupy the earth, the demand for food will constitute a problem which we scarcely apprehend to-day. We shall then be obliged to develop self-sustaining methods of maintaining the producing-power of land. We think we have developed intensive and perfected systems of agriculture; but as a matter of fact, and speaking broadly, a permanent organized agriculture is yet unknown. In certain regions, as in Great Britain, the producing-power of the land has been increased over a long series of years, but this has been accomplished to a great extent by the transportation of fertilizing materials from the ends of the earth. The fertility of England has been drawn largely from the prairies and plains of America, from which it has secured its food supplies, from the guano deposits in islands of the seas, from the bones of men in Egypt and the battlefields of Europe. We begin to understand how it is possible to maintain the producing-power of the surface of the earth, and there are certain regions in which our knowledge has been put effectively into operation, but we have developed no conscious plan or system in a large way for securing this result. It is the ultimate problem of the race to devise a permanent system of agriculture. It is the greatest question that can confront mankind; and the question is yet all unsolved. _The best husbandry is not in the new regions._