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. Fill the tubes with the same kinds
of dry sifted soils. Then pour water into the pan or dish beneath the
tubes until it rises a quarter of an inch above the lower end of the
tubes (Fig. 24). Watch the water rise in the soils. The water will be
found to rise rapidly in the sand about two or three inches and then