48 
THE FLORIST S JOURNAL. 
rigorous weather, when the heat of their dung-casings is de¬ 
clining, they are, as it were, almost at the peril of their plants, 
dared to touch it, for fear of increasing the evil; they know at 
any rate that if, at an immense sacrifice of labour, they do suc¬ 
ceed in replenishing it piece by piece, it is at least two or three 
days before it is again in a proper and effectual state of action ; 
and even this period will be lengthened, if they have not on 
hand a plentiful supply of materials ready for use: they must 
know likewise, even though they may never have had the 
benefit of experiencing it, that a fire could be made up, and 
would produce the effect required, by means of the tank, in as 
many hours as it would take days to do so by following the old 
plan. And mark this — for it is a point of the utmost import¬ 
ance — the tank system will effect this : thus much can now be 
very safely asserted. 
We sometimes hear of the more humid kind of heat given 
out from hot-water pipes than is the case with other appliances, 
such, for instance, as a flue. It is not unfrequently asserted, 
that the heat thus imparted is so moist, so genial, so peculiarly 
adapted to plants. Without doubt, the heat thus obtained is in¬ 
finitely more suited to the development of plants than that de¬ 
rived from a flue : but its superiority consists in its purity, that 
is, its freeness from noxious gases, and not in its possessing a 
greater degree of moisture ; the pipes are composed of a mate¬ 
rial not to any extent porous, and they give off the caloric only, 
which is transmitted from the fire to the water, from the water 
to the pipes, and from these latter to the atmosphere; it is next 
to impossible to conceive any thing more thoroughly devoid of 
moisture than the heat thus communicated to the atmosphere. 
On the other hand, flues are constructed of porous materials, 
and smoke, which contains a considerable portion of the elements 
of water, penetrates more or less through them, and thus the heat 
imparted from a flue, except where it is in immediate vicinage 
to the furnace, or direct source of caloric, will be found to be 
certainly not less, but in a degree more, humid than that from hot- 
water pipes. Its impurity, however, renders it far less desirable ; 
for moisture can be added to the dry heat of hot-water pipes. 
The engraving will perhaps be rendered more intelligible 
by a few descriptive remarks, in addition to the reference 
to the letters. First, I would say that the house should be pro¬ 
vided with a tank near the front, in which a circulation of 
