英文科学读本 第一册·Lesson 33 Coal Ⅱ

Lesson 33 Coal Ⅱ

You know, said Fred, "that coal is mineral; it is dug out of deep mines."

Yes, said Norah, "so are clay, and stone, and sand, and iron, and rock-salt."

But, said Fred, "these things We always in the ground. Coal was not always in the ground. Teacher has been telling us fine stories of a time when the coal-beds were great forests of trees."

Yes, Willie joined in, "and he showed us some pieces of coal, with the shape leaves and ferns on them."

The forests some time or other sank down and got buried, and now they are changed into coal, added Fred.

How strange! said his sister, "And is it all true?"

Yes, teacher says it is quite true.

Would you like to see something very funny? Fred went on.

That I should, said his sister.

Then watch me, he said.

He brought out, in a very sly way, one of his father's clay pipes, with a long stem. He had filled the bowl with small dusty coal, and closed it up with clay, just as he had seen teacher do.

He put the bowl of the pipe into the middle of the bright red fire.

Now, little girl, said he, "just watch."

In a little while they saw some puffs of yellow smoke come out at the end of the stem. The bowl too got red-hot. Then the pipe left off smoking.

Now, Norah, said Fred, "watch again."

He put a light to the end of the pipe. A bright yellow flame burst out in a moment, and Norah gave quite a start.

Whatever is that? she said.

Ah, said her brother, "we knew we should give you a surprise."

That is gas burning at the mouth of the pipe—the very gas that burns in our streets, and shops, and houses.

Norah had another surprise when the pipe was taken out of the fire. After it had got cool, Fred broke the bowl, and showed her that it was full of coke.

SUMMARY

Coal was not always in the ground, as it is now. It has been formed from the remains of great forests, which once grew on the earth. The trees, long, long ago, sank down and got buried and changed into coal.

Coal gives us gas to light our streets, and shops, and houses; and coke to burn in our fires.