ection of Horticultural
buildings of all classes and for all purposes, from the low priced
commercial shed to the finished crystal palaces, that adorn our finest
country seats, has led us to a more thorough investigation of this now
very important subject, and we have been enabled by a long practical
experience in the construction and practical management of Horticultural
buildings to reach conclusions relative to form, combination, heating
and management that could not be arrived at in any other manner.

We have illustrated examples of the straight and curvilinear roofs, and
now give the polyprosopic roof, in which manner we have erected some
half dozen graperies and plant houses.

[Illustration: FIG. 25.--_Perspective._]

This particular form of hot houses was described by Mr. Loudon in his
encyclopedia of gardening some thirty years ago, and he says, "he
considers it to be the _ne plus ultra_ of improvement as far as air and
light are concerned."

Mr. Leuchars in his practical treaties on hot-houses published some
twelve or fifteen years since, illustrates this form of house and says:
"It is by some considered superior to all other forms for winter
forcing."

[Illustration: FIG. 26.--_Section._]

Mr. James Cranston of Birmingham, England, has also adopted this form of
construction, which in many respects he considers ahead of all others.
It seems to have been very generally known and used by many builders of
glass-houses, and its numerous combinations of sliding, lifting, and
permanently fastened sash, has been public property for upwards of
thirty years. Although nearly approaching to the curvilinear, form it
lacks the graceful beauty of a continuous curved line, and as excessive
ventilation so necessary in the climate of England, is not required in
our dry sunny atmosphere, the lifting or sliding sash roof is not
considered so desirable as the continuous fixed roof, which is at once
the most beautiful and the most economical roof yet introduced.

The principal advantage of the Polyprosopic roof, is its portability,
that is, it can be made in sashes, and transported to any portion of the
country, thus obviating the necessity of painting and glazing in the hot
atmosphere of the interior, or loss of time from storms, etc., on
outside work. The fixed roof house can be sent anywhere primed, but the
glazing and second coat of paint must be done after the erection of the
building; either house we think equally wel