Lesson 51 A Lump Of Coal
第51课 一块煤
Let us take a lump of coal in our hand. It is black in colour, and it will dirty our fingers a little, but we must not mind that. Coal is hard; but it breaks into pieces if we strike it with a hammer, and so we say that it is brittle.
小朋友，咱们把一块煤拿在手里看看。这块煤是黑色的，会把手指也染黑一点儿，可不要在意。煤是很硬的，但如果拿锤子敲，就能敲碎，所以我们说煤很“脆”。
Where does coal come from? It is found in beds, or layers, or seams, deep down in the earth. The seams of coal are often from three to eight feet thick, and there are layers of sandstone or of clay between them.
煤是哪儿来的？是从深深的地下的“矿床”或者叫“煤层”中找到的。煤层的厚度一般是3英尺到8英尺，煤层之间是砂岩或者粘土。
Look at each lump of coal before you place it on the fire, and some day you may find the mark of a leaf, a fern, or a piece of bark on the coal.
把每一块煤放在火上烧之前，先看看煤块。有时候，兴许你能在煤块上找到一片叶子，一片蕨类植物，或者一块树皮的痕迹呢！
Coal is now called a mineral, for it is found deep down under the ground; but it was made from trees and plants that grew long ago on the surface of the earth in denseforests. These trees grew up and died and fell down, and others grew on the top of them, till at last a mass of wood was formed many feet in thickness.
煤是一种“矿物”，因为它是在深深的地底下找到的，但它在很久很久以前，是地球表面茂密森林中长着的树和草。树先是长大，然后死去，倒下了，又有别的树长在这些树的上面，最后就积累了许多英尺厚的木头。
Then the land on which these old forests grew sank slowly down, and the sea washed up sand and mud on the top of the mass of wood. Since then the wood has been so squeezed and heated, deep down in the earth, that it has been changed from wood to coal.
后来，这些古老森林下面的陆地，慢慢地沉了下去，海水将泥沙冲到了木头的上面。然后，这些木头在深深的地下被用力挤压，加热，于是就从木头变成了煤。