er course, it is easy to learn all that is necessary
to form a good foundation for a thorough acquaintance with the subject.
If this foundation is laid thoroughly, the learner will regard plants
and soils as old acquaintances, with whose formation and properties he
is as familiar as with the construction of a building or simple machine.
A simple spear of grass will become an object of interest, forming
itself into a perfect plant, with full development of roots, stem,
leaves, and seeds, by processes with which he feels acquainted. The soil
will cease to be mere dirt; it will be viewed as a compound substance,
whose composition is a matter of interest, and whose care is productive
of intellectual pleasure. The commencement of study in any science must
necessarily be wearisome to the young mind, but its more advanced stages
amply repay the trouble of early exertions.

FOOTNOTES:

[M] The spaces between the particles.

[N] In very many instances the crevices and seams of rocks are permeated
by roots, which, by decaying and thus inducing the growth of other
roots, cause these crevices to become filled with organic matter. This,
by the absorption of moisture, may expand with sufficient power to burst
the rock.

[O] Some rocks contain sulphur, phosphorus, etc., and these may,
perhaps, be considered as organic matter.

[P] These distinctions are not essential to be learned, but are often
convenient.

CHAPTER II.

USES OF ORGANIC MATTER.

[What proportion of organic matter is required for fertility?

How does the soil obtain its organic matter?

How does the growth of clover, etc., affect the soil?]

It will be recollected that, in addition to its mineral portions, the
soil contains organic matter in varied quantities. It may be fertile
with but one and a half per cent. of organic matter, and some peaty
soils contain more than fifty per cent. or more than one half of the
whole.

The precise amount necessary cannot be fixed at any particular sum;
perhaps five parts in a hundred would be as good a quantity as could be
recommended.

The soil obtains its organic matter in two ways. First, by the decay of
roots and dead plants, also of leaves, which have been brought to it by
wind, etc. Second, by the application of organic manures.

[When organic matter decays in the soil, what becomes of it?

Is charcoal taken up by plants?

Are humus and humic acid of great practical importance?]

When a crop of clo