FUEL.

"What do you burn in the stoves in your houses?" was asked of a class of schoolchildren in a small Pennsylvania town. Hands went up in every direction; one said "kerosene oil"; two others shouted "gas"; a few replied "wood"; most of the class answered "coal." Then the teacher made further inquiries to learn why these different substances were used. The three who answered gas and oil agreed that coal was burned in other stoves in their houses, but that oil and gas stoves were used also because they were so convenient.

When the question was asked why coal was used, instantly the answer was given that coal was the best thing to burn; everybody burned it. Now this was not quite true, but Miss Turner, the teacher, instead of immediately correcting the error, turned to the pupils who had answered "wood," and inquired why they used wood. One said, "We haven't any coal"; another thought that it was because wood kindled more easily than coal; a third was sure that he was right—"We don't have to buy wood; coal costs money."

Now this boy had the correct idea. He lived in the country, though near the town. His father owned a large farm, a part of which was still forest land; he could cut his own wood, and therefore did not buy coal. After a few more questions the teacher discovered that all those who burned wood lived some little distance from town.

Then she turned to the class again and asked them if they could now tell why the town families used coal instead of wood. One said, "We do not own forests." Another thought that it was because there were not trees enough. A third shook his hand wildly and shouted, "Coal is cheaper than wood!" A shy little girl ventured to suggest, "Because coal is better than wood; it lasts longer."

"You have each of you given a good reason," Miss Turner answered. "Coal is cheaper than wood here in the town because wood is growing more and more scarce. Many of your parents prefer coal because with it the fire needs less attention. But the coal dealers charge more to carry coal out into the country, and those who still own forests find it cheaper to burn their own wood. What sort of replies would I have received if I had asked the same questions of children in Pennsylvania Colony, or in any of the colonies, one hundred and fifty or two hundred years ago?"

The children had studied history somewhat. They knew the story of Columbus and his discoveries; they had read of the Pilgrims and the Puritans; they could have answered questions concerning John Smith and Henry Hudson; and they were especially familiar with William Penn and the Quakers, with George Washington and Braddock's defeat. But not one of them remembered that he had ever been told anything about the fires of the colonists.

There was a pause for a time; then one boy asked, "Didn't they burn just what we burn?" After another pause the shy little girl asked, "Didn't they have more forests then than now?" Before the teacher could reply, a boy said, "Perhaps they did not have any coal."

The children had thus thought it out for themselves, and they were right. Miss Turner then told them that it was many years after the time of Columbus or Hudson or Penn before coal mines were discovered in this country or coal used. She added that almost all the country, from Maine to Georgia and westward across the Alleghany Mountains, was covered with thick forests when the colonists crossed the Atlantic Ocean.

"What do you suppose our ancestors thought of these forests? Were they glad to see them, or did they wish that they covered less ground?" asked the teacher.

Most of the children answered that the forests must have been of great value to the colonists; they would not have to pay anything for fuel.

"Can you raise vegetables or grain in the woods?" was Miss Turner's next question.

Then the pupils began to see that the forests were hindrances as well as helps. The teacher told them that they gave the colonists more wood than was needed for fires and for lumber. She added that every acre of ground that they wished to plant with Indian corn or rye, with potatoes or squashes, must first be freed from the trees. Before the land could be plowed it must be cleared. If, then, the trees furnished more wood than could be used, it was natural for the farmer to burn the trees and stumps in the fields.

If there had been but few settlers and if they had been widely scattered over a large territory, no harm would have resulted. But the colonists came over by the thousands and had large families of children. By the time the country had been settled a hundred years, great gaps had been made in the forests. A few of the most foresighted of the colonists began to think about the future and to wonder what they would do for fuel if the wood should give out. In fact, trees began to be scarce in the neighborhood of the larger towns, and firewood as well as lumber became expensive.

"Suppose that all the forests in this country had been destroyed," the class was asked, "what would the people have done for fuel?"

"Used coal," replied a boy from a back seat.

"Yes," said Miss Turner, "if there were any coal, and if the colonists knew where to find it and how to use it. But what is this coal and where does it come from?"

"We owe all our knowledge of the origin of coal to the geologists, who have made a careful study of the surface of the earth," continued Miss Turner. "They tell us that there was a time when human beings did not live on the earth; when not even animals that need to breathe the air could exist. The atmosphere which surrounded the earth in those days was different from the air which we breathe. We need the oxygen that is in our air to sustain life; poor ventilation in our rooms or halls soon renders them uncomfortable and often causes our heads to ache. The reason for this is the presence in the air of too large a quantity of a gas called carbonic acid gas; an extra amount of it makes the air unfit to breathe, but a certain amount is necessary to sustain plant life.

"In the coal-forming or carboniferous age the atmosphere around the earth contained less oxygen than at present and great quantities of carbonic acid gas. For this reason, as I have said, animals did not exist, but plants—large shrubs, great ferns, and huge trees—lived and grew vigorously. If we have ever seen thick woods we need only imagine all the bushes and trees of the forest to be of enormous size in order to have some idea of the vegetable growth of the carboniferous age. The earth was preparing vast quantities of fuel to be ready, thousands of years later, for the millions of men that were to come.

"The growth of the forests was but one step in the preparation of coal. The second step was the submerging of the forests, covering them with water as if at the bottom of the sea. Then the streams brought gravel, sand, and mud into this ocean, and these were hardened into clay and sandstone by the pressure of the water, perhaps aided by the heat of the earth itself. The trees and ferns were bent down and pressed together and driven into the most compact condition possible.

"But again earthquakes came and the water disappeared. The layer of clay and sandstone was covered with soil which became dry enough to produce other forests, growing as rank as the first. These were again overwhelmed and covered first with water, then with rocks and soil, only to be lifted again for another growth. This process was repeated in some cases many times, as we can see with a little study."

Here Miss Turner stopped and said: "Next Saturday, if it is pleasant, we will have our annual spring picnic. We will go to a new place this time. We will try Howland's Grove, and then in the afternoon we will go down into the Jefferson mine and see what it is like."

We have not time to read about the picnic, nor of the interest that the class showed before the appointed Saturday, as well as all the forenoon of that day. Nor can we tell how the children went down the shaft of the mine, and how they were at first so quiet that hardly a word was said. The teacher showed them a layer of coal in the mine which was about three feet thick. Just above it was a rock which was different from the coal. This they were told was sandstone, the hardened sand which had been heaped upon the forests so many thousand years before. Then below the coal was another rock which was entirely unlike either the coal or the sandstone. This was the seat-stone, the rock made out of the soil in which the forest had grown. Then below this they found three more layers, sandstone, coal, and seat-stone, and so on until the bottom of the mine was reached.

By this time the children were ready to ask questions.

"Oh, Miss Turner, what is this curious-looking thing in this part of the seat-stone?" asked one of the boys.

Miss Turner replied: "That is a fossil. It is part of a root of a tree, and has retained its shape and appearance all these thousands and thousands of years."

One of the miners who had been listening to the conversation said: "If you will step this way, madam, I can show you the whole of a tree-trunk in the coal."

The children eagerly crowded around as the miner showed the fossilized trunk of a tree still standing just as it grew, with its roots in the seat-stone and its top in the sandstone above the coal—for here the layer of coal was several feet in thickness.

A few minutes afterward, as the children were looking carefully at the sides of the mine to see if they could find more fossils, the shy little girl said quietly to the teacher: "I think that I have found something, Miss Turner; won't you please see?"

She led the way to a trunk which showed the various stages in the process of change. One end was still almost like wood, the middle part was a very soft brown coal, while the other end was true coal.

"That helps us to understand more about the way in which the forests were changed to coal," said Miss Turner. "Now here is one more proof that coal was formed out of wood."

The teacher picked up a piece of coal and broke it with a hammer. Then she showed on the new surface some patches of a black substance. "Does not that look like charcoal?" she asked. "You know that charcoal is wood partly burned."

Thus the class learned how nature, ages and ages ago, began to prepare for the use of man a fuel which seems inexhaustible, is superior to wood in many respects, and is freely distributed in various portions of the world. This coal, which has taken the place of wood to a great extent in furnishing heat for our houses and stores, is found in large quantities in the United States, but was not mined or used here until the middle of the last century.