44(> REGULARITY OF HEAT AND ECONOMY OF FUEL. 
you, with a drawing of its construction, and more particularly to the 
reports of Messrs. Wihnot of Isleworth, M’ Intosh, Claremont, and 
other practical and celebrated horticulturalists, which must convince 
you of the great importance and utility of this furnace for all purposes. 
The great injury and annoyance arising to conservatories, gardens, 
and neighbouring dwellings, under all preceding constructions of fur¬ 
naces or stoves, arc, by this invention, wholly and most perfectly re¬ 
moved. In the interior, under the highest temperature ever re¬ 
quired, the heat is genial and bland; no particle of smoke or suffo¬ 
cating vapour is perceptible to the senses, or by those tests which 
can, under such circumstances, be applied. The flue has been 
opened, and at 80 degs. appears to contain or convey nothing but a 
perfectly sweet moist heat; nothing escapes from the chimney but a 
slight steam, and probably carbonic acid gas, as pale and as harm¬ 
less as the steam from the waste pipe of an engine. A similar relict 
from nuisances, and from much greater injury, is obtained by the 
adoption of this furnace in delicate manufactures, in dying, bleaching, 
washing, brewing, &c. &c. and in chemical manufactures. With 
regard to the profit arising from a diminished consumption of fuel, 
the advantage, varying from one quarter to one-third, is common to 
all cases whatever, from the domestic stove to the vast engines which, 
in their operation, render the mines of our country almost as valuable 
as its surface. 
In order to justify the foregoing statement, it will be necessary to 
refer to former usages, and point out whence the present advantages 
arise. The common furnace has usually consisted of a large grate, 
which formed the floor and support of the fire, and it was generally 
surmounted by an arch or boiler, or any body to be heated. It fre¬ 
quently, but not always, had two doors, one to admit the fuel, the 
other to facilitate the stoking, and to draw the ashes; but this exces¬ 
sive extent of grate admits too much air, by which the fire is kept 
helow the temperature required to consume the smoke; and omitting 
all consideration of the clouds of smoke vomited during the first 
kindling and raising the fire, a similar emission of clouds occurs 
whenever a fresh supply of fuel is required, until the parts of the 
coal, which sublime in dense smoke and soot, are dispersed in nuis¬ 
ance and waste. The great cause of this is, that the moment the 
door of the furnace is thrown open, a vast rush of cold air sweeps 
under the boiler, or through the flues, and carries away the heat; 
then the cold, raw, or perhaps wet coal is thrown into the centre 
of the fire, which reduces the temperature, destroying in one moment 
all the effect required, liberating the product of the coal in an impel- 
