lingering in the second or the first in some other respect. But in any line of advance this order is followed. The primitive man picks up whatever he can find suitable for his use. His successor in the second stage of culture shapes and develops this crude instrument until it becomes better fitted for his purpose. Then, in the course of time, man often finds that he can make something new which is better than anything he can find in nature. The savage discovers. The barbarian improves. The civilized man invents. The first finds. The second fashions. The third creates. Primitive man sought shelter in any cave that he could find. Later he dug out the cave to make it more roomy and piled up stones at the entrance to keep out the wild beasts. He gradually enlarged this barricade until from stones he quarried out of the hill he could build a cave above ground anywhere in the open field. But man was not content with such materials; he now puts up buildings which may be composed of steel, brick, glass, and concrete, none of which materials are to be found in nature. The savage might cross a stream astride a floating tree-trunk. By-and-by the idea occurred to him that it would be better to sit inside the log instead of on it, so he hollowed out the log with fire or flint. Later, much later, man built an ocean liner. In the making of clothing the same development can be seen. Primitive man used the skins of animals he had slain to protect his own skin. In the course of time he fastened leaves together or pounded out bark to make garments. Later he plucked fibers from the sheepskin and the cotton-ball, twisted them together and wove them into cloth. Nowadays man can make a complete suit of clothes, from hat to shoes, of any texture, form, and color, and not include any substance as found in nature. Imitate Nature? Yes, when we cannot improve upon her. Admire Nature? Possibly, but we must not be blind to her defects. Learn from Nature? We should sit humbly at her feet until we can stand erect and go our own way. Love Nature? Never! She is ever to be watched and conquered, for at any moment and in spite of all our watchfulness she may wipe out the human race by famine, pestilence, or earthquake, and within a few centuries blot out every trace of its achievement. In fact, it is only by conquering nature that man can rise. Some folks are trying to elevate the laboring classes; some are trying to keep them down. The scientist wants to end them by ending physical labor. There is little need any longer for human labor in the sense of physical toil, for the energy necessary to do all kinds of work may be obtained from nature and can be directed and controlled without great difficulty. Man's first effort in this direction was to throw part of his burden upon the horse and the ox or upon other men. But within the last century he has discovered that neither human nor animal toil is necessary to give him leisure for the higher life, for with the machine he can do the work of giants without exhaustion. Man is a tool-using animal, and the machine, that is, the power-driven tool, is his peculiar achievement. It is purely a creation of the human mind. The wheel, the essential feature of the machine, does not exist in nature. The lever, with its to-and-fro motion, we find in the limbs of all animals, but the wheel cannot be formed of bone and flesh. Man as a motive power has petty strength, but he can make an engine that will do a hundred thousand times as much work as he can do and do it many times as well. CLASS ACTIVITIES Adapted. 1. Explain the three chief stages in man's progress from savagery to civilization. Give examples, not mentioned in the selection, which illustrate these three stages. (If you have trouble in doing this, read again "What the Earliest Men Did For Us," p. 86.) 2. How is the story of man like the story of Robinson Crusoe? How is it unlike this story? 3. "It is only by conquering nature that man can rise." Mention facts from preceding selections which seem to prove this statement. 4. What is a lever? Give examples of levers in your body. For what are levers used in industry? Is the lever as valuable as the wheel? Why? 5. Do you agree with what the author says about loving nature? In what two ways may we use the word "nature"? Contrast its use in Book One, pp. 245-276, with its use in this unit. Name three ways in which we should "conquer" nature; three in which we' should "love" her. 6. Word study: meteorites, barricade, concrete, pestilence, motive. 2. WHAT OF THE FUTURE? LEON CARROLL MARSHALL One way to become a good reader is to form the habit of raising questions as you read. This practice will help you to see and to understand what is important in a selection. While reading this article, make a list of seven questions which will test thoroughly your understanding of the author's thought. Coal, Petroleum, and Natural Gas. Our greatest source of power to-day is coal. Coal is stored sunshine of thousands of years ago! The sun enables plants to grow. Every day the earth's plants absorb thousands of tons of carbon from the air. When they decay, they give this carbon back to the air. If, ESTIMATED PRODUCTION (TONS) OF COAL IN THE UNITED STATES TO THE YEAR 2055, BY DECADES ENDING IN THE YEARS CITED Notice how recently we have begun to consume coal on any considerable scale and how rapidly we are increasing that consumption. however, a mass of plants should become covered by water most of the carbon would not get back to the air but would be retained. in the plants. If this mass should become covered by layers of sediment, pressure and heat would, through long ages, change it first into peat, then into lignite or brown coal, into bituminous coal, and finally into anthracite coal. In the long, long ago world there were a few spots where just the right combination of great masses of plants, water, pressure, and heat made possible the beds of coal which we use to-day. There are, of course, only a certain number of such veins, and nature by no means makes new veins as fast as we tear out the old ones. When we use a ton of coal, therefore, we diminish by that much our supply of coal. We have scattered about in various places in the United States a stock of coal that would make a mountain 18 miles long, 18 miles high, and 18 miles wide, and we have mined less than 0.5 per cent of the original amount. We are, however, using our coal more and more rapidly. Furthermore, many veins of this coal are not very accessible, and many other veins are of poor quality. To make a long story short, the end of our coal supply is clearly in sight within the next few centuries. If we are to live together well through the coming centuries, we must some day find other power resources. We shall not find them in the other fuels of to-day, petroleum and natural gas. Their supply is even more limited than the supply of coal. It is true that there are great quantities of petroleum which can be "manufactured" out of our shales. But as matters stand to-day, this "manufacture" of petroleum is an expensive process. The fuel thus obtained would be an expensive source of power. DEVELOPED 6,000,000 HORSE-POWER UNDEVELOPED 30,000,000 HORSE-POWER AT THE LOWEST ESTIMATE; 55,000,000 TO 60,000,000 PROBABLY PRACTICABLE STATUS OF WATER POWER IN THE Clearly we have only begun to develop our water power-our "white coal," as it is called. that the time will come when water power will be more useful to us than our waning coal supply. Water power does not diminish through use, for it is continually being replaced by nature's rains. It must be remembered, however, that water power cannot be developed everywhere. We can have good water power only in those regions where there is good snowfall or rainfall; where the flow of water is regular or can be made regular by making reservoirs; where the height above sea-level is sufficiently great to get a "fall" as the water returns to the seas; where the surface conditions are such as to concentrate this fall at one point or at a few points, so as to be of service. These areas are neither very numerous nor very large, and some of them, as the world's population is distributed to-day, are located at points which cannot serve many people. Valuable as our water resources are, there can be no question that, as our coal and oil disappear, we shall have to turn to still other powers. One power that man has long dreamed of using is the tides. Here is perfectly enormous power-power that would suffice for any thinkable population on this earth. But how to utilize it is the problem. There have been and still are a few "tide mills" on ocean coasts which catch the water in such a way as to make it when returning to the sea turn wheels as in an ordinary waterfall. The tides are, however, not continuous. They do not come even at the same hour every day. It follows that any large use of tidal power must apparently be made in connection with storage batteries and must wait for some plan which we cannot yet picture of providing "harness" at the shore lines. The same remark can be made of any possible utilization of the waves of the sea. We do not now see how to use these ocean powers on any large scale, but it is entirely possible that these powers will be utilized a few centuries later, when the scarcity of coal begins to pinch. We also dream of using the sun's rays. A few "solar engines which catch the sun's rays and turn them into mechanical horsepower are already in existence. Up to the present time, however, we have not been able to make solar engines that can compete with the coal-heated steam-engines. Perhaps we may be able to do so in the future, but here again the areas in which we can have |