ants; for it is a function of the vegetable kingdom by the action of
their leaves, when under the influence of light, to decompose carbonic
acid, the oxygen of which is liberated, and the carbon fixed in the living
tissue. It is therefore probable that a supply of carbonic acid,
artificially maintained about the leaves and stems of plants, may be
beneficial to them, by furnishing them directly with a portion of carbon,
which they cannot absorb in a seperate state. When the charcoal is made
from twigs, and the small branches of trees, its decomposition is often
more rapid, than when it is obtained by the usual course of manufactering
it: if the latter kind of charcoal is employed, it should be broken into
pieces of a small size; and in ordinary cases, it should not be used in
larger proportion than with about twice its bulk of soil, with which it
should be intimately blended.

Besides its chemical action, which is probably beneficial, charcoal has a
decidedly advantageous mechanical action in the composition of soils, and
this is of a twofold nature:--first, in common with any similar
materials, it renders the soil "open," and thus effectually favours the
free passage of water through its mass: secondly, it serves as a perpetual
reservoir of moisture in the soil, for in consequence of its being
extremely porous, it imbibes a great quantity of water, by its force of
attraction, and this it parts with slowly to the soil; in this way, there
is no doubt that its action is most salutary. Probably a few pieces of
charcoal placed perpendicularly in the soil, and kept continually _wet_,
by the action of some little capillary contrivance, would serve as the
best possible means of conducting moisture, and distributing it to the
roots of plants.

It will be observed that the application of dung, in any way whatever, has
not been recommended; neither do I consider it to be at all requisite, or
desirable, in the culture of winter Cucumbers: luxuriance is not a
consummation which it is at all desirable to attain to, a moderate, well
matured growth, being far preferable; and as some care is supposed to be
used to provide suitable soil, it should be of such a nature as to possess
the properties, which are requisite to effect the desired end. Dung
containing as it does fertilizing properties, may do well to renew the
fertility of exhausted soils, which may have been under a long course of
cultivation; but it is questionable, whether it o