IN A COAL MINE.
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.