n bar some day, and easily root it up.

In the middle of the wood was a fine spring of water, which gushed from
a rock, and then spread out into a little pool, so clear and quiet, that
the smallest stones could be seen at the bottom. Samuel tasted the
water, and found it cold and refreshing. He asked his cousin how so much
water could come out of the rock.

"It does not come from the rock," replied Thomas; "but only runs through
it. Father says, that spring water often comes from the hills and
mountains, running under the ground through cracks and holes in the
rocks, until it finds some outlet. I suppose this water runs down from
the tops of the hills near the iron mine."

"But this is not rain water," said his cousin. "It neither tastes nor
looks like it."

"It has become changed while passing under the ground," replied Thomas.
"After a heavy shower the water soaks into the earth until it reaches
the sand, or rock underneath, then it runs through every little crack
down the hill, and under the ground to some place like this where it can
escape. The sand and gravel, which it meets with, make it pure and the
lime and other substances of the rocks, alter its taste."

[Illustration]

CHAPTER V

WHAT UNCLE HARVEY SAID ABOUT RAIN.

When the boys reached the house, Mr. Harvey was in his study. Samuel was
anxious to ask him some questions about springs, but he would not go up
stairs to disturb him. But after dinner his uncle came into the parlor
where the boys were, and then Samuel asked him where all the water comes
from that flows in the rivers and other streams.

"From the ocean," answered Mr. Harvey. "I suppose you have seen water
boiling, Samuel."

"Yes, sir."

"And have you seen the steam rise up from the water into the air?"
Samuel said that he had. His uncle continued:

"Whenever water is heated, it is turned into steam, or vapor, as it is
sometimes called. If there is enough of heat to make water boil, the
vapor passes off very fast, until the water is gone. Now the sun is
continually changing the water of rivers, ponds, lakes, and of the
ocean, into vapor. This vapor rises. The air about a mile above the
earth, is much colder than it is on the earth; so when the hot vapor
from the ocean meets the cold air, it again becomes water, and forms
clouds. I see you are ready with a question, John."

"Yes, sir," said John. "I cannot see, father, how the clouds can float
in the air if they are nothing