_The soil is the greatest of all resources._ The resources that sustain the race are of two kinds,--those that lie beyond the power of man to reproduce or increase, and those that may be augmented by propagation and by care. The former are the mines of minerals, metals, and coal, the water, the air, the sunshine; the latter are the living resources, in crop and live-stock. Intermediate between the two classes stands the soil, on which all living resources depend. While the soil is part of the mineral and earthy resources of the planet, it nevertheless can be increased in its producing power. Even after all minerals and metals and coal are depleted, the race may sustain itself in comfort and progress so long as the soil is productive, provided, of course, that water and air and sunshine are still left to us. The greatest of all resources that man can make or mar is the soil. Beyond all the mines of coal and all the precious ores, this is the heritage that must be most carefully saved; and this, in particular, is the country-life phase of the conservation movement. To my mind, the conservation movement has not sufficiently estimated or emphasized this problem. It has laid stress, I know, on the enormous loss by soil erosion and has said something of inadequate agricultural practice, but the main question is yet practically untouched by the movement,--the plain problem of handling the soil by all the millions who, by skill or blundering or theft, produce crops and animals out of the earth. Peoples have gone down before the lessening fertility of the land, and in all probability other peoples will yet go down. The course of empire has been toward the unplundered lands. _The soil crust._ Thinner than a skin of an apple is the covering of the earth that a man tills. The marvelously slight layer that the farmer knows as "the soil," supports all plants and all men, and makes it possible for the globe to sustain a highly developed life. Beyond all calculation and all comprehension are the powers and the mysteries of this soft outer covering of the earth. For all we know, the stupendous mass of materials of which the planet is composed is wholly dead, and only on the surface does any nerve of life quicken it into a living sphere. And yet, from this attenuated layer have come numberless generations of giants of forests and of beasts, perhaps greater in their combined bulk than all the soil from which they have come; and back into this soil they go, until the great life principle catches up their disorganized units and builds them again into beings as complex as themselves.