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sufficiently air-tight to prevent the escape of aqueous
exhalations ; a leaden pipe, pierced with small holes,
should therefore be carried round the building, at as
great a height as may be found practicable, and this
pipe connected with a reservoir, so that an artificial
shower could be produced at pleasure ; if an increase
of temperature were considered necessary, it might
readily be attained by the introduction of hot-water
pipes in the usual way.
So great is the advantage of this plan, that the
plants of tropical regions can now be cultivated in
London with the most perfect success ; and, what is
of still greater importance, may be conveyed, uninjured
by extremes of heat and cold, and without any
additional supply of moisture, from the most distant
parts of the earth. Mr. Ward, and Messrs. Loddiges
of Hackney, have, in their glass cases, transmitted
our plants to the most distant countries, and have
received the same cases in return filled with valuable
exotics, many of which have never previously reached
this country in a living state.
But the most pleasing character of this mode of cultivation
is, that it can be adapted to any spot that fancy
may dictate : plants in this way may be grown in a
drawing-room, without ever making the least litter or
apparent untidiness, and without the trouble attendant
on watering. If the cases were opened annually it
would be sufficiently often, and the decayed fronds,
or a too luxuriant growth, might be removed, and a
little water added, if there appeared a necessity for it.
Ferns, mosses, and all kinds of cryptogamous plants,
seem to spring up spontaneously in these cases ; and
the surface of the earth speedily becomes clothed not
only with a beautiful but a highly interesting vegetation.
The raising of Ferns from seed, in the manner
hereafter described, offers a ready way of ascertaining
beyond question the value and limits of each
species.
It has often been considered somewhat unaccountable
that plants should thrive when deprived of air.
I beheve a philosopher would smile at the idea of a
vacuum existing in a vessel containing abundance of
earth, water, and living vegetables; but let us consider
the subject, without reference to any philosophical
inquiry. It must, then, be understood as an
unquestionable fact, that in closing the vessel no
attempt is ever made to exclude the air which it contains,
or even by any experiment to diminish its
quantity; therefore, admitting the property of air to
press equally in all directions, we must take it for
granted that there is as much air in the vessel as in
an equal space outside the vessel; and so, the idea
that the ferns are living without air not being based
on fact, requires no refutation. The next source of
wonder is, that a fern should thrive deprived of that
fresh air, or that change of air, which, in a state of
nature, it is constantly enjoying. The term fresh
air, though so continually used, has no very definite
meaning. If it applies to air that has not been
breathed by animals, I believe we shall find that
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