= 
i PITS. 
state of growth, it is said to have 
the grass fine. 
Fig. 42.—Piping of a Carnation. 
Piera’ntHus. — Legumindse. — 
A handsome haif-hardy tree with 
large yellow pea-flowers. It will 
grow in any common soil, but it 
requires a slight protection during 
winter. 
Pisra‘cra.—- Terebiathicee—-The 
Pistaccia Nut-tree. Very hand- 
some trees, which abound in tur- 
pentine in their native country, but 
which are only half-hardy in Eng- 
land. 
Pits are structures either sunk 
in the ground, or raised above it 
with brick walls on all sides, and 
with a glass cover. For the pur- 
pose of preserving plants from the 
frost, they do not require flues, beds 
of tan or dung, or any other artificial 
mode of heating; but they do re- 
quire artificial heat when they are 
employed for preserving greenhouse 
plants, for growing hothouse plants, 
or for forcing hardy herbaceous 
flowers or shrubs into premature 
bloom. ‘They are also used as a 
substitute for hotbeds in bringing 
forward tender annuals, and in rais- 
ing seeds. For all these purposes 
wy 
321 
PITS 
some mode of artificial heating is 
required; and this may either be 
accomplished by smoke flues, the 
circulation of hot water in pipes of 
iron or earthenware, or by the in- 
troduction of beds of fermenting 
materials, such as tan or dung 
The most convenient mode of heat- 
ing is unquestionably by hot water, 
because by this mode there is less 
danger of producing excessive heat; 
and the heat, from being accompa- 
nied by moisture, is more congenial 
to vegetation than the dry heat of 
smoke-flues. Where hot-water pipes 
cannot be conveniently procured, 
or in the given locality are more 
expensive than smoke-flues, then 
these may be adopted ; taking care 
to supply moisture to the atmosphere 
of the pit by placing pans of water 
on the flues; or by keeping the sur- 
face of the soil, or the path, if there 
be one, moist by the supply of water 
from time to time. The construc- 
tion and the heating of pits are so 
well known to gardeners, builders, 
and ironmongers, that very little 
need be said on the subject. They 
may be of any convenient length— 
six feet, eight feet, or ten feet in 
width, three feet high above the 
surface of the ground behind, and 
of such a height in front as that 
the slope of the glass may form an 
angle with the horizon of between 
20° and 30°. The depth to which 
the pit is ‘sunk in the soil will de- 
pend on the uses to which it is to 
be applied. When it is merely to 
preserve plants from the frost of 
winter, it need not be sunk into 
the soil at all; but when it is to 
contain a bark-bed, the depth of 
that bed, which may be between 
two feet and three feet, should be 
excavated from the soil. When 
the pit is to be entered by the gar- 
dener, in order that he may walk 
upright, there should be a path um- 
mediately under the back wall, and 
this will require the pit to be at 
