Coal has many uses. Mention all you can think of. From which kind is gas obtained, hard or soft coal?

What is coal? Some day you will be able to understand how coal was made, and how it got deep down in the earth.

What article used with food is found in mines? Does all _salt_ come out of the mines? How is the salt made that is not found in mines?

There are salt mines where men, women, and children live all their lives, and never see sun or sky. Many great rooms and galleries, with tall pillars to hold up the roof, are cut out of the salt. When lighted up with torches, they glitter as if studded with precious stones. It is like a fairy palace.

Some minerals are called metals. Iron, gold, silver, copper, tin, and mercury are metals.

Iron is the most useful of all metals. Did you ever think what we should do without this hard, strong metal? The following lines tell some of the uses of iron:

[Ill.u.s.tration: IRON MINE.]

Iron vessels cross the ocean.

Iron engines give them motion; Iron pipe our gas delivers, Iron bridges span our rivers, Iron horses draw our loads, Iron rails compose our roads; Iron houses, iron walls, Iron cannon, iron b.a.l.l.s, Iron lightning rods on spires, Iron telegraphic wires, Iron hammers, nails, and screws, Iron everything we use.

Steel is iron made very hard. Knives, axes, hatchets, and other tools are made of steel. Many little things are made of steel. Mention some of them.

Which is the most valuable of all metals? Is all the gold made into money? Is money made of pure gold? Why? Name articles of ornament made of gold. Articles of use. Are gold watches, chains, and rings usually made of pure gold? Why? What do you call the man who makes these articles?

[Ill.u.s.tration: CASTING IRON FROM THE ORE.]

Silver is the whitest and most l.u.s.trous of all the metals. What does "l.u.s.trous" mean? Is iron l.u.s.trous? Are silver articles usually made of pure silver? Why?

Silver and gold are found among the mountains in the west. Sometimes they are dug out of the ground. Sometimes they are found in rocks, and the rocks must be broken up before they can be taken out.

[Ill.u.s.tration: "SOMETIMES MEN WASH DOWN THE HILLS."]

Sometimes men wash down the hills with streams of water in order to get at the silver or gold among the rocks.

Gold and silver are called the _precious metals_ because they do not rust, and on account of their scarcity.

Tin is white and bright, but too soft to make articles which shall be light and strong. Therefore, thin plates of iron are dipped into melted tin. The tin adheres to the iron and makes it bright like tin itself.

A thin sheet of iron, covered with tin, is called tin-plate. It is of this that our tin cups, pans, and kitchen utensils are made. A tin cup is really made of iron.

Lead is a very heavy metal. It is so soft that it can be cut with a knife. It is used in making shot, and water pipes.

Do you know how shot is made? Did you ever see a shot-tower? Small shot is made by dropping melted lead through a sieve in rapid motion, from the top of a high tower. The drops fall into a vessel of water below.

They are next polished and made black, and then are ready for sale.

You think, I suppose, that the lead pencil with which you write is made of lead. It is not made of lead, but of graphite, which is a kind of coal.

Copper is softer than iron, but harder than lead. It will not rust.

Cooking vessels are often made of copper.

Zinc is another valuable metal, and is almost the color of tin. Bra.s.s is made by mixing copper and zinc together.

Mention some articles made of bra.s.s.

Write five lines about tin.

Write five or more lines about coal.

Write what you know of iron, gold, silver, copper, lead.

LESSON XLII.

MORE ABOUT THINGS FOUND IN THE EARTH.

[Ill.u.s.tration: A GRANITE QUARRY.]

We have seen that there are many kinds of metals. There are also many kinds of stone. Those which are strong and do not crumble by exposure are useful for building. The place from which stones are taken for building is called a _quarry._

The more common stones are granite, sandstone; limestone, marble, and slate.

We will first examine a piece of _granite._

How hard and firm it is! What a beautiful clean surface when polished!

Granite is used for steps, for paving streets, and for sidewalk curbings. Are houses ever built of granite? Can you think of other uses of granite?

Why is granite used for these purposes? It is easily shaped. It is hard enough to give strength. It is enduring. What does "enduring" mean?

This is a piece of _sandstone_, made of little grains of sand. It will crumble more easily than granite. What does "crumble" mean? Brownstone, used in building, is a kind of sandstone.

And this is the common gray _limestone_ of which lime used in building is made. The large oven in which lime is burned is called a lime-kiln.

Did you ever see one? Can you tell how the lime is made?

Here are three pieces of _marble_. This piece is pure white. This is colored. It is marked by many strange forms, as you see in your mantel-pieces and table-tops. In this piece, you see many colored spots--mottled it may be called.

Marble is beautiful when polished.

[Ill.u.s.tration: A MARBLE QUARRY.]

In what different ways have you seen marble used? What parts of furniture are sometimes marble? Why is it suitable for this? Is marble ever used for building houses? Do you think it would be good for that purpose? Why? Which, do you think, is the best of all building stones?

Why?

Marble and granite are the most beautiful and enduring of all building stones.

_Chalk_ is a variety of limestone. Could it be used as a building stone?

Is chalk harder or softer than other stone?

You need not to be told the name of this dark stone. You could not get along well in school without _slate_. Slate is easily split into thin plates, and has a smooth, firm surface.

Slate is used to write on. It is used in house building. What part of a house is sometimes slate? Think of other uses. Why is it useful for these purposes?