Oct.] the HOT-HOUSE. 553 
day. It should be filled with fresh well prepared tan, to the depth, 
of three feet when settled, and the pots plunged therein to their 
rims, the smallest sized plants in front, the largest towards the 
back part. 
The frame should be entirely surrounded with a large quantity 
of the fallen leaves of trees to its full height, having still more in. 
reserve to add, as the others sink and contract in bulk, in conse- 
quence of fermentation and pressure, always keeping them full up 
to the top of the frame on every side; the leaves will soon heat and 
cause the tan to ferment, and between both a fine glow of warmth 
will be kept up in the frame during the whole winter; this, with the 
assistance of a suitable covering of mats, boards, &c. at night and 
in severe weather, will keep the most tender plants in health and 
good condition. 
Linings of hot horse-dung may be substituted in place of leaves, 
but the latter is preferable on account of its slow, steady and long 
continued heat. 
Oak Leaves used as a substitute for Tan. 
As oak leaves abound in almost every part of the United States, 
it is of some importance to know that they may be used in forcing 
pits of every kind, in place of tanner's bark, and with advantage, 
their heat being constant, regular, and continuing for a long time, 
often for an entire year; whereas bark generally turns cold soon 
after its violent heat is gone oif, which obliges the gardener to fork 
it up frequently in order to revive the heat. 
The Sooner the leaves are raked up after they fall from the trees 
the better, as the quality and fermenting substance will naturally 
decrease during the time they are exposed to the weather. 
When raked up they should be carried immediately into some 
open shed, and there thrown into a heap to settle and ferment. — 
In this place tread them well, and water them a little if you find 
they are rather dry. The heap should be at least six or seven feet 
in thickness, and covered with old mats, as well to promote a gene- 
ral fermentation as to prevent the upper leaves from being blown 
away by the wind. They should be suffered to remain in this state 
for four or five weeks, by which time they will be properly pre- 
pared for the pits, and will not settle down much after. In put- 
ting them into the pits, if they appear dry, water them a little and 
tread them in layers, exceedingly well, till the pits are quite full: 
then cover the whole with tan to the thickness of two inches, and 
tread it well till the surface becomes smooth and even. On this 
place your pots of pines or other tender plants in the manner they 
are to stand, filling up the spaces between them with tan as you 
proceed, row by row. 
After this, the leaves require no farther trouble the whole season 
through, as they will retain a constant and regular heat for twelve 
months, without either stirring or turning. 
Leaves mixed with stable dung make excellent hot-beds, which 
preserve their heat much longer than when made of dung only. 
3 X 
