Things Found in the Earth
T HE earth contains many things that are of great value to us. These we must find and dig out.
The coal we burn in our grates to warm us; iron, from which so many useful things are made; gold, silver, tin, lead, and copper,—all come out of the earth.
But these are not all the valuable things hidden away in the earth.
From salt wells we get a great deal of the salt used on our tables. From oil wells is obtained the oil we use in our lamps to give us light. Diamonds which sparkle so beautifully, and the stone we use in building, are also taken from the earth.
Coal, iron, gold, silver, lead, tin, copper, mercury, and salt are called minerals.
The opening dug in the earth from which minerals, except stone, are taken, is called a mine.
One of the most useful of minerals is coal. Did you ever stop to think how much hard work coal does for us? It grinds our wheat, it weaves our cloth, it carries us by sea and by land over the earth. Hardly any labor can be done without coal.
You have noticed that some coal burns with a great deal of flame and smoke. That is called soft or bituminous coal. That hard, clean-looking coal, which burns with little blaze, yet gives out such great heat, is anthracite coal.
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:
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?
Silver is the whitest and most lustrous of all the metals. What does "lustrous" mean? Is iron lustrous? 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. 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. Brass is made by mixing copper and zinc together.
Mention some articles made of brass.
Write five lines about tin.
Write five or more lines about coal.
Write what you know of iron, gold, silver, copper, lead.