, if the course
of the brook were turned, so that it would run in a current over any
part of the soil, it might carry away more than it deposited, and thus
prove injurious. Small streams turned on to land, from the washing of
roads, or from elevated springs, are good means of irrigation, and
produce increased fertility, except where the soil is of such a
character as to prevent the water from passing away, in which case it
should be under-drained.

Irrigation was one of the oldest means of fertility ever used by man,
and still continues in great favor wherever its effects have been
witnessed.

MIXING SOILS.

[How are soils improved by mixing?]

The _mixing of soils_ is often all that is necessary to render them
fertile, and to improve their _mechanical_ condition. For instance,
soils deficient in potash, or any other constituent, may have that
deficiency supplied, by mixing with them soil containing this
constituent in excess.

It is very frequently the case, that such means of improvement are
easily availed of. While these chemical effects are being produced,
there may be an equal improvement in the mechanical character of the
soil. Thus stiff clay soils are rendered lighter, and more easily
workable, by an admixture of sand, while light blowy sands are
compacted, and made more retentive of manure, by a dressing of clay or
of muck.

[Why may the same effect sometimes be produced by deep
plowing?

What is absolutely necessary to economical manuring?]

Of course, this cannot be depended on as a sure means of chemical
improvement, unless the soils are previously analyzed, so as to know
their requirements; but, in a majority of cases, the soil will be
benefited, by mixing with it soil of a different character. It is not
always necessary to go to other locations to procure the soil to be
applied, as the subsoil is often very different from the surface soil,
and simple deep plowing will suffice, in such cases, to produce the
required admixture, by bringing up the earth from below to mingle it
with that of a different character at the surface.

* * * * *

In the foregoing remarks on the subject of mineral manures, the writer
has endeavored to point out such a course as would produce the "greatest
good to the greatest number," and, consequently, has neglected much
which might discourage the farmer with the idea, that the whole system
of scientific agriculture is too expensive for