a 
Steam Engine, 
Description of a Furnace for Steam-Engines^ ^c* zvhich 
effectually consumes the smoke arising from it* In a 
letter to the editors, from Mr. Wili^iam Thomson^ 
of Bow-Lane* 4>Ilep. Arts, 1796* 
^ WITH A PLATE. 
AS steam-engines are much made use of in this king- 
dom, and, at the same time, are often found very disagree- 
able on account of their smoke ; I herewith send you a 
description, and drawing, of a furnace which will effec- 
tually consume the smoke arising from it, without requi- 
ring more coals than usual, as has been the case with for- 
mer contrivances for that purpose. It may be adapted 
to any boiler or copper already set up, and at a very small 
expence. 
Fig. 1, is a section of an oblong boiler, and fire-place. 
aa a a. The brick work in which boilers are usually 
set. 
A A. The boiler. Two iron flues run through this 
boiler, and also go round it. 
B B. The fire-place;: which must te about one third 
longer than they are generally made, 
C. An arch, which runs across the fire-place, two 
inches lower than the bottom of the flue under the boiler, 
and about the middle of the fire-place. 
D D D D. Flues through which the hot air ascends, and 
spends its heat on the boiler, 
E. The door of the fire-place ; which must have a 
small shutter in it. Through this shutter the coals must 
be gently stirred up, by the slice or poker, taking care not 
to inj ure the arch, nor to raise too great a quantity of coals 
at once. 
F is a small space left behind the fire, for a current of 
air to come through, as in the patent lamps. 
