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communication with the atmospheric ingredients, or, in other
words, manures ought to be applied which in part decrease the
binding power of the clay, by which means the earth becomes
looser and more porous.

This effect will be produced by the application of a marl, which
contains more sand than clay, besides a proper quantity of carbon-
ate of lime, or, in the absence of this, air-slaked lime, which has
nearly the same influence, and it seems to me that the application
of this substance is especially appropriated to this class of soils of
which I presently speak. The carbonate of lime in the marl
takes its place between the clay, humus and sand particles of the
soil, and tempers by its presence the tenacity and binding power
of the clay; inconsequence of which the soil may easily crumble,
and its impenetrability to water and the ingredients of the atmos-
phere may decrease; whilst the proportion of sand and clay in
this kind of marl supports this effect. The analyses of these soils
always show a deficiency of lime relative to the proportion of sand
and alumina in them.

The soils of Alleghany county are those which are formed by
fragments of clay slates, of gray sandstone, red sandstone, lime-
stones, &c. They are loamy, rather calcareous soils, as we see
by their analyses above given, and show, as a consequence of their
composition, that they are, pervious to the influence of air, and
permit the rain-water to penetrate them intimately, not to rest
upon them, so that wet seasons will not do any harm here: a dry
season is rather to be feared.

The defect in these kinds of soil, is especially their little depth
and the want of uniformity of their particles, inasmuch as we find
large fragments of rocks intermingled with fine and coarse ones,
as the constituents of their body. In this matter, therefore, our
point of view ought to be directed especially to the deepening of
the soil, and to the restoration of its uniformity, both of which
will be done by means of a decomposition of the rocks. We have
previously seen that the decomposition of volcanic rocks was done
by the action of water slaked lime on them; here a chemical
action, that of lime, was induced to a chemical compound (sili-
cates), and the good result was the consequence of a chemical pro-
cess. In this case, however, the chief compounds present are not
chemical compounds. Those rocks above named, consist princi-
pally of a merely mechanical mixture of substances which we
also find in soils, and their separation, of course, must therefore
also be done by a mechanical process. The application of lime
on these soils would also be inadmissible, for a second and third
reason, inasmuch as lime is already in abundance present in them,
and the whole action of the lime would restrict itself to the de-
composition of the humus, the quantity of which is rather de-
ficient. Lime would act on this soil as on many other soils, for