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<div class="lesson">LESSON XLII.</div>
<div class="chaphead">MORE ABOUT THINGS FOUND IN THE EARTH.</div>
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<td><SPAN href="images/079_l.gif" target="_blank" id="ill79"><ANTIMG src=
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<div class="caption">A GRANITE QUARRY</div>
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<p>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 <i>quarry.</i></p>
<p>The more common stones are granite, sandstone; limestone, marble,
and slate.</p>
<p>We will first examine a piece of <i>granite.</i></p>
<p>How hard and firm it is! What a beautiful clean surface when
polished!</p>
<p>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?</p>
<p>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?</p>
<p>This is a piece of <i>sandstone</i>, 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.</p>
<p>And this is the common gray <i>limestone</i> 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?</p>
<p>Here are three pieces of <i>marble</i>. 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.</p>
<p>Marble is beautiful when polished.</p>
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<td><SPAN href="images/080_l.gif" target="_blank" id="ill80"><ANTIMG src=
"images/080.jpg" border="0" alt="A MARBLE QUARRY." /></SPAN></td>
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<div class="caption">A MARBLE QUARRY.</div>
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<p>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?</p>
<p>Marble and granite are the most beautiful and enduring of all
building stones.</p>
<p><i>Chalk</i> is a variety of limestone. Could it be used as a
building stone? Is chalk harder or softer than other stone?</p>
<p>You need not to be told the name of this dark stone. You could not
get along well in school without <i>slate</i>. Slate is easily
split into thin plates, and has a smooth, firm surface.</p>
<p>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?</p>
<p>We must not forget <i>brick</i> 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.</p>
<p>Have you ever seen a brick-yard? What are some of the uses of
bricks? What is the man called who builds houses of bricks?</p>
<p>Is glass taken out of a mine or quarry? No; but glass is made from
sand; which is also a part of the ground.</p>
<p>In laying brick or stone, the mason uses <i>mortar</i>. Mortar is
made chiefly of lime. Lime is made of stone which comes out of the
ground.</p>
<p>If possible, visit mines and quarries. Take careful notice of all
you see, and on your return to school tell what you have
learned.</p>
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