lamp chimneys may be used for the experiment by tying the cloth over
the tops; then invert them, fill them with soil and set in plates or
pans. The sand will take the water in and let it run through quickly;
the clay is very slow to take it in and let it run through; the humus
soil takes the water in quite readily. Repeat the experiment with one
of the soils, packing the soil tightly in one tube and leaving it
loose in another. The water will be found to penetrate the loose soil
more rapidly than the packed soil. We see then that the power of the
soil to take in rainfall depends on its texture or the size and
compactness of the particles.

If the soil of our farm is largely clay, what happens to the rain that
falls on it? The clay takes the water in so slowly that most of it
runs off and is lost. Very likely it carries with it some of the
surface soil which it has soaked and loosened, and thus leaves the
farm washed and gullied.

What can we do for our clay soils to help them to absorb the rain more
rapidly? For immediate results we can plow them and keep them loose
and open with the tillage tools. For more permanent results we may mix
sand with them, but sand is not always to be obtained and is expensive
to haul. The best method is to mix organic matter with them by plowing
in stable manures, or woods soil, or decayed leaves, or by growing
crops and turning them under. The organic matter not only loosens the
soil but also adds plant food to it, and during its decay produces
carbonic acid which helps to dissolve the mineral matter and make
available the plant food that is in it.

Clay soils can also be made loose and open by applying lime to them.

=Experiment.=--Take two bottles or jars, put therein a few spoonsful
of clay soil, fill with water, put a little lime in one of them, shake
both and set them on the table. It will be noticed that the clay in
the bottle containing lime settles in flakes or crumbs, and much
faster than in the other bottle. In the same manner, lime applied to a
field of clay has a tendency to collect the very fine particles of
soil into flakes or crumbs and give it somewhat the open texture of a
sandy soil. Lime is applied to soil for this purpose at the rate of
twenty bushels per acre once in four or five years.

Which soils have the greater power to absorb or pump moisture from
below?

=Experiment.=--Use the same or a similar set of tubes as in the
experiment illustrated in Fig. 23. F