"Then I can learn too. Perhaps there's a man in the steel what lives there and makes it cut."
"If there is, he must have a pretty warm berth sometimes."
"Father, when you learn and I learn, can I make me a hatchet?"
"And me too?" said Robert.
"Yes, I guess so."
Now we intend as briefly as possible to answer Clem's first question. It would be very ridiculous, if a good-looking, nice-feeling boy in the high school, being asked what made his knife cut, should have to stick his thumb in his mouth, look like a dunce, and say, "I don't know."
We must begin with and say a few things in relation to iron, from which steel is made.
The iron ore is put into the furnace, a layer of iron ore and another of coal, together with lime, either in the shape of oyster-shells or stone lime. It is there melted and run into large junks called pigs. The lime causes all the flint, sand, and earthy matters to melt and separate from the iron, which, being heaviest, drops to the bottom of the furnace, while the slag, that is lighter; floats on top, and is taken off. This is cast iron; you see pigs of it piled up on the wharves in seaports, the outside incrusted with the sand in which it was run, and looking as rough, some of it, as the cinders of a smith's forge. It is highly charged with carbon, coarse, hard, and brittle; can neither be filed, welded, nor worked, under the hammer; is more or less filled with slag and other impurities, and fit only, when melted again and purified, to be cast into pots, pans, stoves, wheels, and various articles. It is now melted two or three times more, and slightly hammered, to beat off some of the slag. Then it is made red hot, and put under steam-hammers. In old times it was hammered by water power, or by men with sledges. This is done in order to take out the carbon, that renders it hard and brittle.
Probably by this time you wish to know what carbon is, to extract which from the iron has cost so much labor. Should I give you the definition of the books, you would probably want that definition defined.
Many boys have seen a diamond: that is carbon in a solid form: pit coal is solid carbon mixed with sulphur, phosphoros, and other elements. Charcoal is solid carbon in a nearly pure state. Carbon has so strong an affinity for oxygen, that when any of the substances that contain it are burned, they give up their carbon, that instantly mingles with the oxygen of the air.