something of the power of the soil to absorb and hold moisture for the
use of the plant. Also the importance of knowing if we can in any way
control or influence the water-holding power of the soil for the good
of the plant.


SOURCES OF SOIL WATER

From what sources does the soil receive water? From the air above, in
the form of rain, dew, hail and snow, falling on the surface, and from
the lower soil. This water enters the soil more or less rapidly.


ATTITUDE OF THE SOILS TOWARDS WATER

Which soils have the greater power to take in the rain which falls on
their surface?

[Illustration: FIG. 21.
To show what becomes of the water taken from the soil by roots.
Moisture, sent up from the roots, has been given off by the leaves and
has condensed on the glass.]

[Illustration: FIG. 22.--PERCOLATION EXPERIMENT.
To show the relative powers of soils to take in water falling on the
surface. _A_, sand; _B_, clay; _C_, humus; _D_, garden soil.]

=Experiment.=--Take four student-lamp chimneys. (In case the chimneys
cannot be found get some slender bottles like salad oil bottles or
wine bottles and cut the bottoms off with a hot rod. While the rod