210 
REMARKS ON STEAM AND HOT WATER. 
These circumstances having been proved by experience, engineers 
have employed themselves in contriving the best form and size of 
boilers, and the means by which the burning fuel shall have the most 
direct action on them. One eminent engineer has invented a most simple 
apparatus, to which no boiler at all is used, a coil only of an endless 
pipe being placed in the fire. The pipe used is small—is air and water¬ 
tight, with an expansion tube attached. The action of this apparatus 
is impetuous, and, for the diffusion of heat, most surprising. The coil 
of pipe in the fire is sometimes red-hot, so that the water is circulated 
with wonderful rapidity. This invention is secured by a patent, and 
has been erected in many places with great success, when worked with 
care and moderation. Boilers formed of pipes are also coming into use, 
which are very quick in action, and may be worked at a small expense 
for fuel. In short, such is the variety of forms and powers of hot water 
machinery, that almost any degree of heat may be obtained for any 
purpose, and in any place. All the expedients for preserving or forcing 
early fruits or flowers in gardens may be certainly accomplished by the 
aid of a hot water apparatus properly constructed, and erected in fit and 
proper buildings, from the raising of small salad in the winter months, 
up to the growth and maturation of the largest pine-apple. 
It is most material, however, that the machinery be adapted to the 
purpose for which it is wanted. For the service of a common green¬ 
house, peach-house, or vinery, an apparatus of the simplest construction 
and most substantial material should be chosen. Here instantaneous 
action, or very high temperature, or many dips or turnings of the pipes 
are not at all wanted; but merely a steady heat uniformly evolved, 
and capable of being raised twelve or fifteen degrees when necessary. 
But when it is intended that the same fire shall heat several houses— 
when there is much branching of the pipes, with stop-cocks for turning 
the current off, or for allowing it to pass onward,—then, indeed, the 
whole apparatus must be more complex; and the boiler, whatever its 
form, must be of corresponding dimensions and capacity. 
For the purpose of hotbed forcing, for pits and hot-houses—in all 
which some fermenting substances are used, and for which the heat of 
steam or hot water is intended to be substituted,—the principle before 
alluded to is equally applicable ; but the place of the boiler, the position 
and evolutions of the pipes under the bed on which the plants are to 
grow or be placed, must all be well considered and planned; the accu¬ 
mulated body of heat must be thrown into a chamber below the plants, 
and which is either left vacant or filled with round pebbles, or other 
substances which shall be receptive and retentive of the heat discharged 
from the pipes, and readily admit its ascent through the body of mate- 
