Not all of the muddy streams are due to the carelessness of men. It is the business of some of the servants of Nature, as we have already learned, to tear down the mountains and fill up the hollows in the earth. It is the business of others to spread a carpet of vegetation over the surface, and wherever they have already succeeded in their work the waters run clear most of the time.

Where it is dry so much of the time that few plants can live, the destructive servants have their own way when the occasional rains come. Where there is a warm sun and frequent rains, a green carpet is spread over all the slopes. But when men destroy the carpet and take no care of the soil underneath, the raindrops are able to do as much damage as they do during the cloudbursts in the deserts.

The Colorado is one of those rivers in the basin of which few people live. Much of its journey is through a land in which there is little vegetation. Here, the waters from the melting snows upon the lofty mountains about the basin and those of the occasional heavy rains have things their own way. They are always yellow with mud. The amount of mud which this river carries has been measured. You will hardly believe me when I tell you that it amounts to sixty-one million tons every year. This is enough to cover 164 square miles one foot deep. We might call this the cream of the soil from all the slopes of the great basin of the Colorado River.

In other parts of our land, where abundant rains fall, the streams tell a different story. Before men came the water of these streams was clear throughout the greater part of the year. It was only when the rains were very heavy that the soil washed away, for the vegetation held it well. Now the gullies on the hillsides and along the roads tell us as plainly as though they could speak that our country is losing wealth here.

The soil is our most valuable possession. The people of many lands are suffering from poverty today because their forefathers did not take care of the soil as they should. In such lands the people who live on the mountain sides are poor, because the best of their soil has been washed away. Those who live in the valleys are often poor because of the sands and gravels which floods have spread over their fertile fields.

While it is raining, let us fill a bottle from some muddy stream and allow it to stand until the water settles. In the bottom will then appear a layer of fine mud, or silt as it is usually called. How much soil do you suppose the rivulets washed from my garden and from yours during the last severe storm? How much do you suppose all the rivulets which make up the rivers of your state washed from all the gardens and fields during the same storm? Make a guess and then multiply your answer by the number of storms in one year and that by fifty years, and you will get a quantity greater than you would believe possible.

This is the way Nature takes her toll for our carelessness. So quietly does she do it that often the farmer does not have any idea of what is happening. She is like a thief that comes and steals his goods while he is sleeping.

When the farmer finally awakes and begins to wonder why his crops grow smaller each year, he has already lost the cream of his soil. He must at once stop plowing the steep hillsides and leaving the ground bare for the winter rains to wash it away. To save the slopes he can either terrace them or he can sow grass or clover, which will form a sod and hold the soil. If the farmer can get peas, beans, alfalfa, or clover to grow upon his wasted lands, they will make it fertile again, for these plants have the wonderful power of taking nitrogen from the air and storing it in the soil.

More earth has been washed from the hillsides of our country during the last fifty years than during thousands of years before white people came. The farm lands have been injured, the bays have been made shallower, and many river channels have been so filled up that it is more difficult to navigate them now than it was in the early days.

The farmer, the stockman, the lumberman, and the miner has each been selfishly doing his share in the destruction of the soil. Each one has thought only of how he could make the most money in the shortest time. It has not occurred to them that they are making it difficult for their children and grandchildren to live.

In the Southern states thousands of acres are being gullied by the rains, and the soil destroyed. The floods of spring have become worse in late years, because of the destruction of the forest cover in the Appalachian Mountains. Buildings and bridges are frequently carried away, and gravel and boulders are washed over the rich bottom lands.

In the mountains of far-away Italy the soil is poor, and so are the people. They have cut down nearly all the trees and for hundreds of years the brush and grass have been eaten so closely by the sheep and goats that few roots remain to hold the soil. It does not need to rain heavily there to cause the rivers to become muddy and swollen. The soil which once covered the slopes has been carried to the bays, and now there is land where ships floated two thousand years ago.

In Spain so much of the best soil has been lost that the people now do not raise enough food to support themselves, and much has to be imported from other lands.

France is a rich country still, in spite of the cutting of so much of the forest and the careless pasturing of the mountain slopes. The people are industrious and hard working and thus make a living in spite of the loss which they are suffering.

The Montenegrins are among the bravest people of Europe, but their land is barren and they enjoy few luxuries. Their country consists largely of limestone mountains, from which they have been cutting the trees for hundreds of years. There is but little soil and that is to be found in the hollows of the rocks. This soil is so precious that every bit, be it ever so small, is carefully cultivated.

In the mountains of Palestine and Syria the people have so completely destroyed the trees and grasses which Nature once planted there that it is difficult for them to raise enough to live upon. The rivers are muddy after every rain, and even the water from the melting snows picks up some of the soil and flows away with a dirty, yellow color.

When we reach China and Korea, we find that there the people have been most severely punished for their carelessness. The mountain sides have been torn by the rains and deeply gullied. The once smooth slopes upon which grew trees and grasses are now a mass of sharp ridges and deep hollows of bare earth. The water falling upon these mountains runs off in torrents, carrying even large boulders as it does in our Western deserts. Here and there the natives have built terraces of rock to aid in holding the soil, but many parts of the country are almost wholly deserted. The waters run off the mountains so quickly that they often form vast floods which spread over the lower valleys and plains. The floods destroy the crops and drown the people.

Eastward of China there is an arm of the Pacific Ocean known as the Yellow Sea. Why do you suppose this name was given to the sea? One of the great rivers of China, the Yangste-kiang, empties into it. The river rises in the barren mountains of which we have just been speaking, and it is continually bringing so much mud and sand that a whole sea is being filled. Long before a ship comes within sight of the land the waters are seen to be of a muddy, yellow color.

In the smaller valleys of Korea the natives build dikes along the rivers to keep the mountain floods from spreading sand and gravel over their rice fields. Every year they have to make the dikes higher as the river beds fill up.

Thus we see that all over the world people are suffering because they have not obeyed the laws which Nature has made for the protection of the soil.