The utterly free outdoor life is not open to many. We have little or no opportunity to become acquainted with Nature, the guardian of our ancestors. The woods, the rocks, the mountains, and the dashing streams are almost complete strangers to many of us. Many men are now obliged to go every day to their work in office or shop, and spend the hours shut in from the fresh air and bright sunshine. At night they sleep in rooms into which they admit little fresh air for fear of taking cold. To-day each man has to learn to do one thing well to the exclusion of nearly everything else, in order to make a living. For this very reason we are in danger of becoming human machines and of losing the use of some of the powers with which Nature has endowed us. Many things about our present mode of life are not natural to us, but through successive generations we have become somewhat adapted to them. The Indians, if taken from a life in the open air and made to live as we do, often sicken and die. The farmer enjoys much more freedom and more of the sweet fresh air than do the artisans and office workers; but of all the men in civilized countries the trappers and prospectors live most out of doors. To be sure, they have to endure many hardships and dangers, and their beds are not always the softest nor their food the best, but you will seldom find one who is willing to exchange his free life for work in the town or city. The trappers have nearly disappeared. Their occupation will be gone with the passing of the wild animals which were once so abundant. The prospectors are, however, becoming more numerous year by year throughout the mountains of western America. To them we owe a great debt, for had not their searching eyes brought to light the hidden mineral deposits this portion of our country would be far more thinly populated than it is to-day. The discovery of gold in California was accidental. A man named Marshall was building a mill for Sutter in the foot-hills of the Sierra Nevada mountains at the time (1848) when California had just come into the possession of the United States. While at work he noticed some shining grains in the sand of the mill-race. A little testing of the grains led him to the conclusion that they were gold. The news spread rapidly over the world, and since that time a constantly increasing tide of gold-seekers has been pushing out into the unexplored portions of the earth. Comparatively few of these men have become wealthy, but their discoveries have led to the settlement of new regions and to the growth of important industries. In truth, if it were not for the deposits of valuable metals, large areas of the desert and mountainous West would be of small value. [Illustration: FIG. 96.--A PROSPECTOR IN THE DESERT]