g disease, was reduced to commercial fertilizer, it would supply
the equivalent of from six to nine pounds of rock phosphate per year for
every acre of cultivated land in the United States. And this valuable
product is now totally lost, and worse than lost, since it menaces the
life and health of great numbers of our people.

There still remain to be considered the rock phosphates, the form in
which phosphorus is found in separate deposits. The only large deposits
that have been used are in Florida, South Carolina, and Tennessee, and
from them about two and a quarter million tons were mined in 1907.
Unfortunately, however, there is no law that prevents its export from
this country, and almost half of this found its way to Europe, where it
is eagerly sought at high prices.

Within a short time valuable phosphate beds, more extensive than any
before known to exist in this country, have been discovered in Utah,
Wyoming, and Idaho. Professor Van Hise, who is one of the highest
authorities on the subject, says of these deposits that with the
exception of our coal and iron lands, they are our most precious mineral
possession; that every ounce should be saved for the time which is
coming when the population will have outgrown the capacity of the land,
and means of increasing its fertility in order to prevent famine will be
sought from every possible source.

The other great waste of the soil is by erosion, or the wearing away of
the soil by stream-flow. We can all see this in a small way by wandering
along the shore of any swift-running stream and noticing how the banks
are worn away, and what deep gullies and ravines are cut into them by
the water running down from the fields above. Another way in which we
can observe the effect of this waste is by noticing the muddy yellow
color of streams during floods and after heavy rains, and comparing it
with the clear blue of the same stream at ordinary times.

When we realize that this muddy color always means that the water is
filled with soil, all that it will hold in solution, that it is carrying
away the top soil, which is best for agriculture, and, finally, that
every little streamlet and creek, as well as the mightiest river, is
carrying this rich soil-deposit downward toward the sea in its flow, we
begin to see how great a factor erosion is in the wasting of the land.

The Missouri River, which drains a large area of wheat and corn land, is
notable as a muddy, yellow river