is admitted whenever the sashes of an ordinary frame or of a pit,
are opened, in order to bestow these necessary attentions. It may be urged
that a dung bed has still the advantage, on the ground of economy; but
when a fair calculation is made of labour and loss or anxiety on the one
hand, and of duration on the other, such an assumption, will be quite
untenable. Neatness, convenience, certainty, and economy, are the
principal points of advantage which are gained by the adoption of pits
heated by means of hot water, over those of a structure, depending for its
supply of heat, on the aid of fermenting masses; whilst the attainment of
a still greater degree both of convenience, and of certainty, which may be
secured by cultivation in forcing houses, point out at once the advantages
which render such houses, preferable to pits.

The application of the gutter system of heating, was not long since
thought to be an improvement of great importance, and there can be no
question but that it affords a means of regulating the moisture of the
atmosphere of hothouses, in conjunction with the temperature, which prior
to its introduction had not been attained; and as such, it is worthy of
extensive adoption: it requires however some judgement in its adaptation
to particular structures, and to render, it suitable, to effect any
particular object for which it may be employed.

The tank system as a means of applying bottom heat, employed either in
conjunction with the gutters, or with ordinary piping, to supply heat to
the atmosphere, is the most important advance which has hitherto been made
towards supplying the wants of those plants, which require such peculiar
aid; and with reference to the Cucumber, it may be regarded as furnishing
a new era in its cultivation.

The importance of bottom heat in the culture of tender plants, has always
been well known by its practical effects. The mean temperature of the
soil, at a slight distance below the surface, is universally above that of
the superincumbent air; and consequently some degree of bottom heat is
always supplied to plants, in a state of nature. Naturally, by means of
subterraneous heat, and also by the absorption of the sun's rays during
the time they are forcibly directed towards the earth, it possesses the
means whereby any material degree of cold at the roots of plants is
prevented; and when the soil is acted on by the unveiled sun of an eastern
sky, we cannot but feel certain,