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.
| 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?
We must not forget brick in our talks about things that come out of the ground. Brick is not found in the earth, as the metals and stone are found; but it is made of clay, which is itself a part of the ground.