ation is now carried on through all portions of
the United States where the rainfall is light and streams of water
are available.

To one who has lived in a country where there is plenty of rain,
it seems to involve a great deal of work to prepare the land and
to conduct water to it. One may feel pity for the farmer who has
to support himself in this manner in so barren a country. I am
sure, however, that if any such person will stop to think, he will
remember times when in his own fertile home the expected rain did
not come, and the vegetation wilted and dried up. He may have become
discouraged because of a number of "dry years," but probably never
thought that he had the means at hand to make up, at least in part,
for the shortcomings of Nature, in sending too much rain one year,
and another year too little.

[Illustration: FIG. 113.--WATER-WHEEL FOR LIFTING WATER FOR IRRIGATION,
VIRGIN RIVER, SOUTHERN UTAH]

It would doubtless have paid such a farmer many fold to have been
prepared at the coming of a dry year to turn the water from a
neighboring stream over his lands. This process would have involved
a good deal of labor; but how the plants would have rejoiced, and
how abundantly they would have repaid him for the extra trouble!

The showers come without regard to the time when growing things
need them most, but with irrigation the crops are independent of
the weather. The farmer may be sure that, if he prepares the ground
properly and sows the seed, the returns will be all that he can
wish. In many localities several crops may be raised in a year
by this method where otherwise only one would grow.

Now let us see how the water is taken from the streams and what
are the different methods employed to distribute it over the land.
Almost every valley is traversed by a stream, great or small. It
may be a river, with a large volume of water, or a creek which
completely dries up during the long, rainless summers of the West.

[Illustration: FIG. 114.--GARDEN IRRIGATION, LAS CRUCES, NEW MEXICO]

In rare cases the stream may flow upon a built-up channel which
is as high as the valley, but usually it is sunken below the level
of the floor of the valley, and enclosed by banks of greater or
less height. How is the water to be sent over the land? Where the
current is swift you may sometimes see a slowly turning water-wheel,
having at the ends of the spokes little cups, which dip up the
water as the wheel revolves and po