nd forests in its course;
But it blows the windmills strong,
And it sends big ships along.

Watch the pretty snowflakes fall,
Some are large and some are small;
Look, they cover all the ground,
Miles of dazzling white around;
But this covering, I am told,
Keeps the earth from frost and cold.

Ah! and I must work alway,
Life's not meant to spend in play;
Every moment's fleeting fast,
And our day will soon be past;
If our work is truly done,
It will last though ages run.

Of what use is rain? Of what use is snow? Of what use is wind?

LESSON XIV.

HOW WATER IS CHANGED TO VAPOR.

What happens when a kettle of water is put on a hot stove?

The water gets hot and boils away.

Where does it go? Is it destroyed?

The water is changed, but it is not destroyed. Coal burns, but we do not
get rid of it altogether. It is changed into gas and smoke and ashes.

What is the water changed into?

It is changed to vapor. If we let the kettle remain on the fire long
enough, the water it contains will all pass away as vapor.

Where does the vapor go? The water, though turned into vapor, must be
somewhere.

It is floating about in the air of the room, though we cannot see it.
The air holds the vapor, just as a sponge holds water.

Heat expands or swells air. Warm air, therefore, can contain more vapor
than cold air. On a warm day there may be many times as much moisture in
the air as on a cold day.

Moisten your slate with a damp sponge. Observe the disappearance of the
moisture.

Dip your hand in water, and wave it in the air. The water on your hand
disappears. Where has it gone?

When wet clothes are hung on the line, they soon become dry. What
becomes of the water in the clothes?

If we set a plate of water out in the sunshine, what happens? Is the
water lost?

The streets and roads were wet and muddy, now they are dry. What has
become of the water? Has it all sunk into the ground?

Sometimes we see leaves and grass sparkle with water-drops, early in the
morning, When the sun shines out and warms the air; what happens?

Why does vapor rise into the air?

Why does smoke go up? Because it is lighter than air. As vapor is
lighter than air; what do you think ought to happen to it?

LESSON XV.

HOW VAPOR IS CHANGED TO WATER,

Heat, as you have learned, changes water into vapor. You must also know
that cold turns vapor back into water again.

[Illustration: "THINK