140 
r U R N A C E. 
find it bed to life a fniall proportion of charcoal, fome- 
titnes fo little as a two luindrcdth part of the weight of t!ie 
irort : Reel produced with any proportion of cliarcoal, not 
exceeding one hundredth^ will generally be found to pof- 
fefs every property tiecelfary to its being calf into tliofe 
ihapes which require great eladifity, drength, and foli- 
dity ; it will alio be found generally capable of fudain- 
sng a white heat and of being welded like malleable iron, 
and indeed as the proportionof charcoal brother carbona- 
ceous matter is reduced, the qualities of the deel will be 
found to approach nehrer to thofe of cominou malleable 
iron. By further purfuing the principle of my new in¬ 
vention, I fufe down rnalieable bar or ferap iron, in a 
crucible, w’itliout any vilible addition of carbonaceous 
matter, and run it into bar, ingot, or other, moulds; in 
this date the metal is nearly of the fame (juality as when 
put in, only altered by the combination of a fmal! por¬ 
tion of carbonaceous matter wluch rlie irort by its chemi¬ 
cal affinity attrcibfs from the ignited fuel, or from the ig¬ 
nited carbonic gas of the furnace,■ and which enters by 
the mouth or through t!ie pores of the crucible, proba¬ 
bly didbived in caloric at a very high temperature ; but 
whether fo didbived or not, tlie fact is, that a propor¬ 
tion of tire carbon pallesfrom the fire into union with the 
iron, and thereby converts it into an extier.iely foft deel. 
Beddes the different modes of operation above fpecified, 
I further reduce iron-ore, bar-iron, or fcrap-iion, by the 
addition of lime, or chalk, or other carbonates, or of car- 
buters with clay, glafs, and other fluxes, in various pro¬ 
portions, ami form all the various qualities of deel for¬ 
merly enumerated. If the various kinds and qualities of 
deel obt.'iined'by the procefs or procelTes above-mention- 
ed, be introduced into the common converting or other 
■fteel furnaces, in contaft with carbonaceous matter, or 
with earths, and heated for five days, more or lefs, ac¬ 
cording to-the thicknefs of the bars or other forms, and 
the quantity introduced, the bars, ingots, or other 
diapes, being then taken from the furnace, will be found 
to poli'efs all the folidity which they were formerly pof- 
feflTed of as caft-deel, with that property of welding pecu¬ 
liar to blidexed-faggot, or German-fteel, of the ufual 
mode of manufaiffure. 
“ By tiiis invention I obtain deel, which for folidity may 
be tiled for ilie purpofes of cad-deel, uniting at the fame 
time the property of welding without dedroying the foli¬ 
dity or quality of tiie metal, a circumftance of the higheft 
importance to our manufadtures. Ingots, bars, plates, 
and every diape into which this deel is cad, rolled, or 
hammered, will be podeded of uniformity of quality 
without thofe ntimerotis reeds, flaws, bliders, and dif- 
joined laminas, found in deel made by tlie proceflTes in 
life before my invention. When pit-coal cokes are to be 
ufed in any of the foregoing operations, either in mixture 
with the ore, or with the iron, or for fuel in tlie furna- 
ces, in which the crucibles containing the mixture are ex- 
pofed to the adtion of the fire, it is of the utmod import¬ 
ance rhat the cokes be properly prepared. The procefs 
wliich I have found toanfwer bed for this purpofe, though 
common cokes will alfo do, is founded upon the principle 
that all accefs of oxygen to the coals to be coked (hoiild 
be prevented : this end is gained by preparing the cokes 
in iron veflels in the fame manner as wood is now cliarred 
for the purpofe of being employed in the manufadhire of 
gun-powder ; the bitumens, or coal-tar, as it is common¬ 
ly called, which is volatilized from the coals to be coked 
by the heat applied to the exterior of the iron veflel, or 
other chamber, containing the faid coals, is thus faved, 
indead of being burnt or dillipated in the atmofphere, as 
is the cafe in the common procefs of coaking, in which 
the coals are expofed to combudion in open heaps, and 
which all'o partially, though in a lefs degree, takes place 
in the piocels, commonly known by the name of “ Lord 
Piindonald’s procefs for preparing coal-tar;” but as it is 
X)f importance in large manufailories that the procefs of 
coaking diouldkeep pace with the other procefles con. 
nedted with metallurgy, that a fufficient quantity of 
cokes may always be at command, of an uniform quality, 
it may be necelfary in many cafes to prepare furnaces 
foniewhat different in condrudlion, but agreeing in princi¬ 
ple with the one for preparing charcoal, which has above 
been generally alluded to.” The following condriidlion 
of a coaking furnace, but which may be varied in form 
according to the form of the feite of particular manufac¬ 
tories, and other circumdances, will be found calculated 
to produce cokes of an excellent quality, aaid at the fame 
time a faving of all tlie bitumen, or coal-t.ir, volatilized 
by the procefs, and where circumdances render it advifa- 
ble, will admit of metallic ores being roaded at the fame 
time, along with the coals-to be coked in the interior of 
the drutture, or with fuch a proportion of coally matter 
as Amply to tonify the ores, or iion doiies, for the blad- 
furnace. 
Fig. 9, in the preceding Plate II. reprefenrsan end fec- 
tion of this furnace. A, the adi-pir, (ix feet wide at the 
bottom, and narrowing to four feet at the bearer, which ;i 
placed acrofs to fupport the furnace bars. B, the iron 
bearer. C, the fire-place. D D, tiie commencement of 
the flue, whicli furrounds the interior building of the fur¬ 
nace fix inches high, and two feet broad; of thefe flues 
there are eight in the length of the prefent furnace, and 
their number may be extended or diminillied in propor¬ 
tion as the furnace is condrufted of a larger or fmaller 
fize, as thefe flues conduct the flame and heat from the 
ignited coals upon the grates, the interior part of the fur- 
iiace and its contents become thoroughly lieated. The 
vapour arifing from the coals or ores expofed to ignition, 
together with the flame and fmoke of the coals ufed for 
fuel, efcape by the aperture E, of which there are alfo 
eight in the extreme length of the prefent furnace: any 
greater length of chimney may be added above the pre¬ 
fent, as circumdances may point out ; the fame apertures 
may alfo ferve to ciiarge the furnace. F, a final 1 door in 
the front of the furnace, which ferves to empty it of its 
contents. G, plate of cad iron which ferves for tlte bot¬ 
tom of the furnace, and on which the fide walls are built ; 
the under furface of tliis plate is cad with a number of 
fiiiali protuberances, which, when covered with a'coating 
of clay, keep hold of the fame, and prevent the oxyda. 
tion of the iron, although expofed to a conliderable de¬ 
gree of heat. In place of an iron plate, an arch of fire 
bricks on edge may be fubdituted, particularly where 
there is no fcarcity of fmall-coal or other fuel; indead of 
making the Tides of fire bricks as reprefented in the en¬ 
graving, cad-iron plates with flanges may be fubdituted, 
which will tranfmit the heat with greater facility than 
brick. Fig. lo, exhibits a top view of the furnace cut 
acrofs at the fpring of the arch. DD, D D, D D, the 
fide flues as tliey rife from the Tides of the furnace, to con¬ 
vey the heat and flame betwixt the inner and outer arches. 
E, E, E, apertures by which the fmoke and vapour, 
arifing from the fide flues, and from the cavi;y of the fur¬ 
nace,niaketheir efcape ; their dimenfions are twelve inch¬ 
es, and may be either round or Iquare; in order to fa- 
cilitate the ignition of the materials acted upon for didil- 
lation, it will be necelfary to introduce into every fecond 
flue, a wooden plug, to red with its under end upon the 
bottom of the furnace, which are withdrawn w hen the 
furnace is filled. The fire is then laid upon the grates at 
C, and fed with culm or wade coals; in a lliort time the 
cavity of the furnace, oi coaker, and its contents, become 
completely ignited, vapour and fmoke are diiengaged in 
large quantities, and carried off through the apertures 
E, E, E. 
Fig. II, reprefents a furnace of a fimilar diape, and 
condrutiled upon the fame principles, but which is calcu¬ 
lated to colletf and coiidenfe the Imoke and vapour into 
pit-coal tar, which is volatilized in this new procefs of 
charring. A, theadi-pit. B, the bearing bar, or plate. 
C, the fire-place. D, D, the fide flues, as deferibed in 
fig. 9. E, E, flues by which the fmoke arifing from the 
1 fuel 
