these pioneer plants lived forever. They grew old in time they died. But at their death they left a valuable contribution to the world. They left the riches they had accumulated: the elements they had secured from the rocks, the substances of their growth, the wee beds of soil they had secured from their forefathers, from the donations of the wind, and from the gifts of air and moisture.

With this wealth available, there was no longer so great a struggle. The decayed plant life in the crevices and the deteriorated rock afforded better feeding grounds for plants, more soil for support, more food for the needs of maintenance and of growth. Consequently, this bettering of material necessities afforded increased opportunities for growth. A higher order of plants might now come. So the small struggling plants, through a long course of years, changed, now gradually, now suddenly, into stronger varieties and species-onward and upward in the scale, until the time when soil was present in abundance, when the higher plants, useful for food and raiment, might be secure and safe, thoroughly fitted and abundantly adapted to all the environmental conditions needed for their complete development and growth.

The work of plants in soil building. It follows, then, that every kind of plant is a soil builder. The decay of the plant at once produces a change in the texture of the soil-making material. It is this addition of the organic matter the dead plant-that produces this constantly performed miracle: for as the plant decays in the soil, the particles of soil in contact with it likewise decay. In other words, soil rotting is soil making. Decay of any material in the soil-organic or not-favors and induces the breaking down of the various complex compounds forming the rock, or the raw or the untamed soils.

The addition of vegetable matter to the soil has assisted in soil making from the time that plants came first to the planet; it has increased the efficiency of all other agencies ever since the early days; and at the very present time it is the soil builder's best friend,-its decay is essential to the feeding of plants.

The roots of plants have done their work in soil making. A great work it has been! For they have gone down deep into the soil making tiny channels for air and water; creeping into the crevices of rocks, they have continued their growth and their enlargement, in the end, breaking

many rocks asunder, dislodging others from their beds, exposing all to the disintegrating influences of air and moisture, of heat and cold.

And roots

especially the small, fibrous oneshave a solvent action as well. The juice they exude at the tips, and the moisture with which they surround themselves, work a change in the soil particles between which they grow; limestone or granite or feldspar or mica slowly but surely succumbs to the deteriorating action of root life.

Animals the modern soil makers.-Soil making

advanced when animals first made their appearance. But animals of all sorts have been potent workers in soil making, the higher animals largely by the manurial return to the land and the lower forms through the manurial effect, but also in directly affecting the physical conformation of earth.

For does not the ant seek the earth for its home and shelter, to construct there its house of many rooms, with the many tunnels connecting the dwellings of the nation? What are these homes and these tunnels but underground traps for air and moisture-soil builders?

Besides the work done in this direction, a tremendous quantity of earth is annually turned over and exposed to sunshine and rain, to heat and cold, to every influence concerned with soil making and soil improvement.

Every sort of insect or animal that burrows into the soil, that opens it, or tunnels it, or loosens it, contributes not a little to soil making: the ant that builds there, the mole that tunnels, the prairie dog or hedgehog that burrows, the earthworm that glides and crawls, and even eats and digests-all are man's good friends in having had a hand in preparing the surface of the earth for the luxuriant growth of vegetable life.

The task of the earthworm.-The task that has been the earthworm's is a most important one. So simple are these creatures, so faithful are they in their labors, so undemonstrative in their duties, we scarcely give them a thought save the time when we seek them for bait for our fishing traps. But the earthworm has for ages been busy opening the soil to air and water, and even more: it eats the raw soil underground and plows its way upwards and downwards, casting at the surface the unused portions of its eatings. In doing this, the muscular gizzard of the worm is ever busy rubbing and grinding stony

particles, mixing with these the organic matter taken into the body system; with these go the secreted slime that has a dissolving effect-useful in making subsoil and untamed earthy constituents available as food for plants.

As proof of the great good of these indefatigable workers, we have the evidence of Charles Darwin, who after long study and observation declared that in many parts of England as much as ten tons a day of dry earth annually were passed through the bodies of these common worms of the field. He also calculated that as much as ten inches of the upper surface of the soil passed through their bodies every fifty years. You can gather from this evidence what worthy workers these insignificant animals have been in preparing the earth for the habitation of man. The increased production of all products of the garden, of the orchard, and of the field has been due, in not a small measure, to these underground helpers and to these wonderful workers in soil making.

CHAPTER III

WHAT WE FIND IN SOILS

Having come now to the point where soils are made, we may with all propriety consider their physical nature, and then the treasures they hold fast secured in their earthy storehouses. Not that soil making has ended, for this process goes on forever. Only this: a time has been reached in their development when, with the aid of tillage tools, the most productive and useful of plants might now be grown for the highest profit of man.

Let us go out into the field itself. Of what is this soil made? was at one time the first inquiry. Naturally, it was said that soils were derived from the original rock formations. We have discussed already the agencies that have made our soils. No single one is responsible for yours or mine. That we possess these soils, there is no. doubt. What brought them to us, what placed particular soils within the limits of our possessions, what influence or agency made them rough or level, good producing or poor producing, is not the problem now.

Four kinds of soil materials. Our present inquiry is in reference to their physical conformation, to their component parts, to the minerals composing them. These materials are: sand, silt, clay, and humus or organic matter. All productive soils contain these materials, but not in the same proportions. There is a wide difference in the quantities of each in our many varieties of soil. A preponderance of one of these materials over the normal