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pit is closed below with slabs of stone (e). Tlie pit is heated by ching-liniugs ( / ) ,
enclosed by walls (g), and kept diy by drains (h), and by a gutter to the sashes (i).
The plants ai'C inserted in a liill (k), and gi-adually earthed up in the usual manner.
This pit is much cheaper than MTliaiFs, especially if tho retaining walls (g) arc omitted.
1996. The essential portable structures arc the common hotbed frame with fiat sashes ;
and next in order, the canvas curtain, or netting-screen.
SuRSECT. 2. Structures partly Movable.
1997. Plant structures, partly movable, are pits and adapted frames. The characteristic
of the pit is, that it is sun-ounded by a wall of earth or masomy, enclosing a pit or bed
for containing dung or bark. The characteristic of the adapted frame is, as the name
imports, a hotbed frame, adapted to some structure of timber, masonry, or iron.
1998. O f the p i t The species are the eaith, walled, flued, vaulted, and pillar-pit.
1999. The cold p it with earthen sides is in part sunk in the earth, and in part raised above
it by walls of loam or turf. On these walls, glass frames are sometimes placed ; and at
other times, only mats or canvas frames. Such pits are used by nurserymen and
market-gardeners, and answer perfectly for the preservation
of half-hardy plants. A pit of this Idnd,
used at Valleyfield (Jig. 561.), is a sunk walled excavation,
3^ ft. wide, 3 ft. deep at the back, and
1 ft. 9 in. in front. I t is covered with thatched
movable fi-ames, wliich are tilted at pleasm-e by a
notched prop. I t is used as a kind of store-place
for all culiuai-y vegetables in leaf which are liable to
be destroyed by frost, such as cauliflower, broccoli,
lettuce, endive, &c. These, before the winter sets in,
are taken up from the open ground, with halls of
earth, and embedded on a bottom layer of rich soil,
filling up the vacancies between and among the stems
with old bark or decayed leaves. An- is given, on all occasions, when it can be done
with safety; and, in severe frosts, additional coverings of litter are put on.
2000. The common cold p it is also pai-tly sunk in the gi-ound, and in part raised above
i t ; but instead of earth or tu rf walls, they arc formed of brick or stone, finished witli
a wooden coping the width of the wall, in which cross rafters arc mortised to support
the sashes.
2001. The flu ed p it (fig. 562.) is the
same as the last described, with the
addition of a flue, which either makes
the cfrcuit of the pit, or runs along
and retm-ns by its back wall.
2002. The vaidted pit, in its simplest
foi-m, is the walled pit with an arch
thrown from the front to the back waU.
Under the ai-ch the fire is made, or
steam admitted; or, in some cases,
fermenting litter thi-own in.
2003. O f adapted frames, there are MThail’s, or the frame with dung-flucs; the pit
with a rising fram e; and the frame with props.
2004. MPhaiVs frame (Jig. 563.) consists of two pai-ts, the fi-ame (a a) and lights (b),
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which arc of wood, and not different fi-om those used for gi-owing cucumbers, or other
similar purposes; and the basement (c d) on which the frame is placed consists of flues
of brickwork, with the outer wall uniformly perforated, or, as it is commonly called,
pigeon-holed, as shown at f . Against these perforated fines Immgs of dung aie
formed, the steam of which enters tho flue, aud heats tho eai'th (e e e) in the ccntio of
each light. The chief obicctions to this plan are tho first cost and the greater consumption
of dung, wliich some allege is required to keep np tho p rq ic r heat. Its advantages
are, that hot dung may he used without any preparation, by which much heat is gam ed ;
and, that in the winter months, when a powerful artificial heat is requuud, which (in the
case of common hotbeds) is apt to burn the plants, they are here in the coldest paj-t of
the soil, and cannot possibly be injured hy any degree of heat which can be communicated
M o o ? ' The p it with a rising frame (fig. 664.) contains a basement-wall of brickwork,
of the height of the dung or hark (a a) ; and in this is a perpendicular vacuity (b b), m
which a common frame (e c ) is placed, and, by a spindle pinion, &c. ( J d), may he raised
¿ lo w e r e d at pleasm-e. Its object is the samo as that of Weeks’s frame, already
Leserited and which it attains with less risk to the plaifrs, hut at a great compai-ative
expense. This variety of pit is the invention of John Nmrn (Hort. 7>-ons., vol. iii.),
who has had it executed, and heated by sun-ounding tubes (e e) fllled wnth steam.
2006. Athinson’s melon pits (fig. 565.) are fonned of brick heated by dung, and consist
of four external walls, of which the back and sides are four inches thick, ancl built
L the M o M t e tn a n n i (a). The front is a hollow fourteen-inch wall, open at top
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withinside (6), and externally fomed with thin bricks set on edge in cement (c)
Against these waUs the dung is applied as u su a l; by which means diy heated ¡m is
communicated to the pit from the front, and the damp warmth ft-cim the steam of the
dung penetrates the pit at the hack and sides. This contrivance is simple, and free fiom
the fbjectionablo points in M'Phail’s pits, especially in hcing much less expensive and
P‘1“ fi"" cucumbers and melons (fig. 666.) may he of any conveinent
length, according to the mode in which they ai-e heated. On the snpposition that
smoke-flues are employed, the length may he from 30 to 40 ft. and the coLses’
incluaing the brick path. Each pit has one fire ancl a flue, which makes 1 / “
two nnder the pit (a a), and one along tho pathway, to heat the an J™ " M
Over this last flue is a nan-ow pit or box, m the way of hoi'der (c), “ M i
for the cucumhers or small melons, which ai-e framed to wires suspended
(d). The soil in this border may he increased hy laying one or more courses of bucks
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