FURNACE. 
feeing fuch as are in common ufe, Tliefe new-invented 
fire-pjaces are alfo applicable to furnaces for almoft every 
other purpofe. 
An inventionofa fimilarkind has alfo been prefented to 
the public by Mr. W, ThompfoiijOf Bow-lane, London. 
He defcribes it to be “ a furnace which will effeblually 
confume the fmoke arifing from it, without requiring 
more coals than ufual, as has been the cafe with former 
contrivances for that purpofe. It may be adapted to any 
boiler or copper already fet up, and at a very final 1 ex¬ 
pence. Fig. 7, in the engraving, is a leftion of an oblong 
boiler and fire-place; aaaa, the brick-work in which 
boilers.are ufually fet. A A, the boiler. Two iron flues 
run'through this boiler, and alfo go round it. B B, tlie 
fire-place; which mufl; be about one-third longer than 
they are generally made. C, an arch, which runs acrofs 
the fire-place, two inches lower than the bottom of tlie 
flue under the boiler, and about the middle of the fire¬ 
place. DDDD, flues through which the liot air af- 
cends, and fpends its heat on the boiler. E, the door of 
the fire-place; which muft have a fmall fliuiter in it. 
Through tliis fhutter the coals muft be gently flirted up, 
by the dice or poker, taking care not to injure the arch, 
nor to raife too great a quantity of coals at once. F, is a 
fmall fpace left behind the fire for a current of air to come 
through, as in the patent lamps. G, a brick placed with 
its whole length acrofs the fire-place, to hinder the coals 
from falling down the fpace F, and choking it. Fig. 8, 
is a front view of the fame boiler and fire-place, in which 
the fame letters reprefent the fame parts. H H, are two 
Hides, the one fliifting backwards, the other forwards, to 
make the fpace F, for the current of air, larger ©r fmall- 
er, ashy pradlice may be found neceflary. 
“ The manner in which this furnace operates is thus : 
The arch C, hinders the fmoke from going up the chim¬ 
ney, and obliges it to pafs through the fire behind it ; 
which has a very ftrong draught, and burns the fmoke as 
it pafiesthrough. The air which comes up through the 
fpace F, gives trefh vigour to the flame, which confumes 
any fmoke that may be left. It mufl be obferved that 
too much air will have a very bad efiedf, as it will cool 
the flame; therefore the Aides H H, muft be regulated in 
fucb a manner as the operator may find moft advantage¬ 
ous. The fluitter in the door E, muft alfo be of a pro¬ 
per fize ; as its being too large, or too fmall, will be pre¬ 
judicial.” 
A further improvement on Furnaces has been recently 
made by Mr. David Mufliet, of Glafgow, fbr the pur- 
pofes of metallurgy, in forming bars, ingots, &c. The 
inventor defcribes it as follov/s : “The general princi¬ 
ples of tny proceffes are, the fufion of malleable iron, or 
of iron ore, in fuch manner as immediately to convert them 
wXo cajl-jieel •, and likewife, in certain cafes, the after ce¬ 
mentation of this fteel, to give it malleability, and the 
property of welding, in order to fit it for fuch pur- 
pofes as require fteel poirefting thofe properties. Tb.efe 
principles can be afted upon for the produddion of the va¬ 
rious qualities of fteel, in a variety of ways; but the prin¬ 
ciple of my invention, and the mode of operation, may be 
fully underftood by the inftances which I ftiall adduce, 
and which will enable any perfon to perform tlie fame, 
and to vary and alter the mode of operation, according 
to his intention, and the particular quality of fteel he may 
with to manufadlure. Thus caft-fteel may be made by 
taking any convenient quantity of malleable iioii, ac 
cording to the fize of the furnace and crucible to be em¬ 
ployed, and introducing it into the crucible, along witii 
a proper proportion of charcoal, charcoal-duft, pit-coal, 
pit-coal duft, black-lead, or plumbago, or of any fub- 
flance containing the coally or carbonaceous principle; 
but in general charcoal, pit-coal, pit-coal cokes, efpe. 
dally if prepared in the manner hereafter deferibed, 
will be found to anfwer beft ; for this procefs not only bar- 
iron may be employed, but alfo what is commonly called 
feraps or wajtc iron j but when the latter is ufed, a little 
1 
more carbonaceous matter muft be added to the mixture 
to revive the ruft or oxyd of iron adhering to the (craps: 
tlie mixture in the crucible nnift fee put into a furnace 
capable of giving a fufliciently intenfe degree of heat to 
run down or fufe the mixture, which muft be tlien pour- 
ed out into bar, ingot, or otlier, moulds, according as 1 h.e 
maniifadiuer intends to produce bars or ingots, or vari¬ 
ous articles or utenlils that are or may be made of caft- 
fteel; for the whole iron by fufion, with the charcoal or 
other fubftances, or things containing caibonaceous mat- 
ter, will be found to have palfed into the ftate of caft- 
fteel. If caft into bars or ingots, and a proper quantity of 
ch.ircoal or other fubftances or things containing carbona¬ 
ceous matter has been employed, fuch bars, or ingots, 
will be found in a ftate ready to take the hammer, and to 
be drawn or rolled into other (hapes, according to the in¬ 
tention of the manufadturer. In fome cafes, efpecially 
wliere a heavy charge is to be run down, the cruci¬ 
bles muft be previoufly difpofed in the furnace, and tlie 
mixture introduced into them afterwards by the procefs 
before deferibed, and wliicli may be v.iried by any pru¬ 
dent operator. Caft-fteel -may be made in a few liour.s, 
which by the procelfes hitherto difeovered, has uliially 
required many days, and fometimes weeks ; for caft (ieel 
by the commdn method of manufacture has been hitherto 
made from bar-fteel which liad previoufly required for its 
own converfion into that ftate, from the ftate of bar-iron 
or ferap-iron, a tedious cementation with charcoal in a 
furnace coijftrudled for the purpofe, and ufually known 
among manufafturers by the name of a convcrtuig iiwnoico. 
It cannot therefore efcape obfervation, that this is not 
the only favitig in point of time and expeace gained by 
my procefs or proceffes ; for wlien I meet with or pro- 
cure iroii-ftones, or iron-ores, fufliciently rich, and free 
from foreign mixtures, I fave even the time and expence 
necelfary for the converfion of fuch iron-done, or iron- 
ore, firft into caft or pig iron, and afterwards by a tedious 
and expenfive procefs, accompanied with a great wafte of 
metal, into bar-iron ; for fuel) ore, or iron-ftones, being 
previouily roafted or torrified, when that procefs may be 
found necelfary, may be fubftituted for the bar-iron 
feraps, or wafte iron, as before deferibed, and the refult 
will be caft-fteel, if a proper.quantity of charcoal, char- 
coal-di’.ft, pit-coal, pit-coal duft, plumbago or black- 
lead, or of any fubftances or things containing carbona¬ 
ceous matter, had been ufed for tlie common and ordina¬ 
ry qualities of caft-fteel ; a much fmallcr quantity of car¬ 
bonaceous matter is requifite in the mixture than perhaps 
would have been fufpected, before my invention: wlien 
charcoal from wood is employed, a I'eventieth to a nineti¬ 
eth of the weight of the iron will generally be found fuf- 
ficient : when the quantity of tlie carbonaceous matter or 
principle exceeds one feventietli, and is increafed from 
one fixtieth to one fortieth or more of the weight of the 
iron, the fteel becomes lb completely fufible that it may 
be run into moulds of any lhape, and be capable after¬ 
wards of being filed and polilhed. Hence by calling may 
beconftrubted ftoves, grates, kitchen utenfils, many kinds 
of wheels, and mill works, a great variety of (mail ma¬ 
chinery, and many otlier articles, which could not be lo 
made fey the procelfes before in ufe, and which way of 
making fuch articles conftitutes a part of my invention. 
By my procefs various kinds of fteel, differing as much 
from each other in their qualities as the various kinds of 
pig orcaft-iron differ from each other, can be formed by 
merely varying the proportion of carbonaceous matter, 
Caft-fteel of the common and ordinary quality is lo vola¬ 
tile when in fufion, as to admit of being run into any 
lhape, except llraight moulds of a confiderable diameter; 
but fteel of fuch denlity as to admit of being caft into any 
form may be produced by my procefs, by increafing the 
quantity of charcoal or matter containing the carbonace¬ 
ous principle, and then fufing the mixture as before di- 
refted. When I wilh to produce qualities of fteel lofter 
than is ufually manufaiflured by the common procefs, ! 
find. 
