Have you ever seen a brook or creek? A river? Is there a brook or river
near here? Who can tell where it begins? where the water conies from
that fills it? where it goes? Let us try to understand this.

As vapor rises into high, cool air, or is carried with the air in winds
up the sides of mountains, it turns into water again, and comes falling
down as rain.

Now think where the rain that falls on mountains must go. Some of the
water runs off on the surface, down the mountain slope. Some sinks into
the ground, and runs along in little streams below the surface. It will
appear again, bubbling out of the mountain side as a _spring_. The
spring is the beginning of a river.

Did you ever see a spring? Where was it? Was it shaded by trees? Where
did the water come from? Did you drink from it? Was the water pure and
cold? Where did the water go after leaving the spring?

[Illustration: "DID YOU EVER SEE A SPRING?"]

From the spring flows a tiny, thread-like stream, so small that we can
easily step across it. This little stream is called a _rill_.

Other rills meet this, and form a larger stream, which is called a
_brook_ or _creek_.

[Illustration: RIVER FROM ITS SOURCE TO ITS MOUTH.]

As the brook flows on, it is joined by other streams, until, little by
little, it becomes a wide and deep _river_ on which large boats may