CHAPTER TWENTY-FOUR
WHAT SHALL WE DO WHEN THE COAL, OIL, AND GAS ARE GONE?
If coal, oil, and gas were suddenly taken away, all the nations would become poor and many of their industries would cease. Just think for a moment of the amount of work these things do for us and what an effort there would be made to find something to take their place!
Wood once formed the chief fuel. It was used only to cook our food or to keep us warm. Now fuel is required for so many different purposes that with the decrease of the forests wood has been found insufficient.
Peat is one of those substances that has been used in parts of Europe to take the place of wood, but it is used so little in our own country that many have never seen it.
Peat is dug from bogs or marshes. We might say that a peat marsh is the beginning of a coal bed. Peat is the partly decayed vegetation which has slowly accumulated in wet places. In the colder countries it is formed largely of moss and similar water-loving plants, but where the climate is warm other kinds of marsh vegetation, and even trees, aid in forming peat. Sometimes floods bring earth and deposit it in the marshes, in which case the peat is less suitable for fuel, but forms a rich and productive soil instead.
In many of the vast swamps of long ago, when there were no men nor even the higher animals upon the earth, vegetation grew very rank. It is believed that at that remote time the air contained more carbonic acid, a substance which promotes the growth of plants. Thus the plants in the warm, moist parts of the earth grew more densely and luxuriantly than they usually do today.
In the decay of this vegetation deposits similar to the peat marshes were formed, but they differed in being much thicker and more extensive. If the story of these ancient peat marshes had stopped here, we should never have had any coal. Fortunately it did not, for some of the swamps sank beneath the water of a lake or ocean and thick beds of gravel, sand, or clay were deposited over them. While buried deep in the earth, the decaying vegetation was heated and pressed together by the great weight of the earth above, and was finally changed to shining, black coal.