IMPROVEMENTS IN THE MANUFACTURE OF MALLEABLE IRON AND STEEL, AND IN FURNACES AND APPARATUS EMPLOYED FOR THEIR FUSION AND TREATMENT
Year: 1869

page_text: LETTERS PATENT to Henry Bessemer, of Queen Street Place, Cannon
Street, in the City of London, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF MALLEABLE IRON AND STEEL, AND IN FURNACES
AND APPARATUS EMPLOYED FOR THEIR FUSION AND TREATMENT."
Sealed the 6th July 1869, and dated the 10th May 1869.
PROVISIONAL SPECIFICATION left by the said Henty Bessemer at
the Office of the Commissioners of Patents, with his Petition, on
the 10th May 1869.
I, HENRY BESSEMER, of Queen Street Place, Cannon Street, in the
City of London, do hereby declare the nature of the said. Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF MALLEABLE IRON AND STEEL, AND
IN FURNACES AND APPARATUS EMPLOYED FOR THEIR FUSION AND TREATMENT," to
be as follows:-
These improvements relate to the fusion of malleable iron and steel,
and other carburets of iron, in furnaces in which the gaseous products
of combustion are retained under a pressure exceeding that of the ex-
ternal atmosphere, as in the high-pressure furnaces described in a Patent
/

page_text: granted to me, and bearing date the 10th day of November 1868 and
numbered 3419.
The improvements constituting my present Invention consists,―
Firstly. In certain modified forms of the reverberatory furnace, and
in each and every of such modifications I employ an outer shell or
casing constructed of plates of iron or steel securely rivetted together,
or of cast iron secured by hoops, bolts, or ties of malleable iron or steel,
the shell in either case being well caulked and rendered air-tight at all
laps and joints, and of sufficient strength to resist safely an internal
pressure of one or more atmospheres in excess of the external atmo-
pheric pressure, as set forth in the Patent herein-before referred to.
The lining of all such modified form of furnaces may be made with fire-
brick, plumbago, or ganister, or other refractory materials, and the
tuyeres for conveying a blast of air therein may also be made in
the manner set forth in the Specification of my former Patent before
referred to.
In one modification of the furnaces so constructed I form a feeding
chamber of the whole or nearly the whole breadth of the hearth of the
furnace, from which it rises vertically near that part usually called the
fire-bridge. I prefer it to be a rectangular chamber sufficiently large to
contain the greater part of the charge of the metal to be melted, it may
be lined with brickwork or in a similar manner to the rest of furnace,
and at top may have a door, through which the metal is put in, and
which is then closed by a simple metal fitting, which may be protected
from the effects of heat by the leakage inwards of air or steam, or the
iron doors lined with fire-brick may be luted with lime or clay slip, and
be secured against the internal pressure by cottered studs, or by bolts
and nuts, or by any other suitable and convenient mode of fastening.
The fire chamber may be circular or D-shaped, the straight side of
the D being next the hearth. I prefer to make a low roof to such
furnaces in order to keep the flame well down upon the metal on the
hearth when melted. The escape aperture being at the end of the
furnace furthest from the fire chamber the flame and heated matters will
have to pass through the interstices of the loose heap of scrap or other
metal which descends from the feeding chamber and intercepts the free
passage of the flame to the exit aperture. As the lower part of the mass
fuses the remainder of the metal sinks down and takes its place until
all is fused.

page_text: In the second modification I omit the feeding chamber, and in lieu
thereof I make a feeding door at the end farthest from the fire chamber,
using by preference a nearly flat shallow hearth. The scrap, wrought,
or malleable iron, and steel, or other kind or quality of metal, I make
into small piles on a board or tile, or on pieces of plate metal, and these
I introduce on a peel or shovel, commencing to pack them first near the
fire bridge in rows near each other until the whole charge is put in.
I prefer that a space be left beneath the piles, which may be for that
purpose propped up on wood, brick, or metal pieces, so as to allow the
flame to pass under, between, and over the piles, well heating the hearth
and the lower part of the piles before fusion takes place. The escape
apertures I prefer to make one on each side of the furnace, or to make
one only at the top or roof near the feeding door.
In the third modification of the reverberatory furnace I make the
whole of the roof moveable, so that by means of an over-head crane the
metal shell of the furnace roof and the lining of that part may be readily
removed by loosening a series of cottered studs or bolts and nuts. This
roof may be replaced by another while the former one is undergoing
repair, the joint where the roof unites with the other portion of the
furnace being rendered sound and air-tight by a mixture of 3 to 6 parts
of ganister to one of fire-clay made into the consistancy of mortar and
evenly spread between the flanges. The hearth and fire-chamber may
by the removal of the roof be quickly cooled down and repaired.
prefer to line the roof and other parts of the furnace with a much less
thickness of lining than is usual in reverberatory furnaces, and to cool
the external shell of such furnaces by a close or open jacket, through
which water flows for the lining, if made thin enough to allow some of
the heat absorbed by it to escape outwardly, and in consequence to
prevent the lining rising to a destructive temperature, thus by the loss of
a little heat a much greater durability will be given to the furnace lining.
I
In each of the three modifications of the reverberatory furnace before
described the fire may be made in a well or chamber with coke, a blast
of air being introduced at several tuyeres; the furnace door may also
be closed in each case in the manner described in my former Patent of
the 10th of November 1868, and before referred to, in which case it is
desirable to obtain a greater length of flame than can be obtained from
the combustion of coke alone, I therefore when not employing a liquid
hydrocarbon for that purpose prefer to employ pulverized coal in a fine

page_text: granular state or completely reduced to fine powder. I introduce the
coal into the blast pipe by means of a small wheel having radial blades
which fit accurately into a race or groove, the blades projecting into
the blast pipe, so that the blast may carry forward the coal at the speed
at which the wheel delivers it. I prefer to make the blast pipe so small
in diameter as to ensure a powerful current between the feed wheel and
the tuyeres, the coal powder may thus be forced in among the lumps of
incandescent coke in any desired proportion, or the coal powder may be
burned in a suitable chamber alone, as now practised in other furnaces.
Or in lieu of this mode of burning coke and coal mixed, or coal
alone, in the form of powder, I construct the reverberatory furnaces after
either of the modifications herein-before described, except in so far as
the fire chambers thereof are concerned, using in lieu thereof a fire-grate
and ash-pit made after the manner of fire-grates of ordinary rever-
beratory or puddling furnaces, such fire-grate and ash-pit being arranged
with a suitable door or slide, so as to allow the ash-pit to be cleaned
out when required, and be closed air-tight or sufficiently so for the
purposes of my Invention, and in which furnace I am enabled to burn
the ordinary furnace coal used in reverberatory furnaces. I also make
a door or slide in order to gain ready access to the fire-bars, so that the
workman may remove the clinkers and adjust or remove a fire-bar if
necessary. When using a fire-grate I prefer to introduce the air for
combustion in a diffused state through numerous openings into the ash-
pit, and I also prefer to employ a chimney with an opening leading
from the after part of the furnace into it, in addition to the restricted
opening, through which alone the gaseous products of combustion pass
while the furnace is working under high pressure. With a furnace so
arranged I am enabled to first heat the hearth and body of the furnace
and the piles of metal to be fused therein by using the chimney draught,
the door in the ash-pit being open, so that the metal may be heated up
to a welding heat without a forced blast, the fire may then have fresh
fuel put on to it, and all doors securely closed, and the blast applied,
using, by preference, a very high pressure for a short time, so as to
rapidly fuse the charge of heated metal and give it a high temperature.
During the open furnace heating there will be generally a tendency to
oxydise the metal somewhat, so that by this mode of working a very
mild metal may be obtained, or a proportionately larger quantity of pig
or other carburet of iron may be combined with it.

page_text: In reverberatory furnaces in which these improvements are used white
or grey pig iron may be melted on the hearth (slowly if desired), or it
may be supplied in a molten state to the furnace, and in either case be
more or less decarburized by the action of free oxygen passing over it
along with the furnace gases, the pressure may then be put on and the
heat increased, and the scrap or other malleable metal forming part of
the charge be fused and incorporated with the partially decarburized
pig iron so employed, a blast of air to facilitate the decarburation of the
metal may be let in at the fire bridge or at the feeding door, and so
also red ore or other oxidising materials may be employed with the
charge of pig metal to facilitate its decarburation.
Another improvement in reverberatory and other furnaces working
under high pressure consists in forming a second heating or melting
chamber, into which the flame and heated gaseous products of com-
bustion from the furnace proper are allowed to flow, the second chamber
being provided, by preference, with the restricted escape aperture, the
passage or opening leading from the furnace proper to the second
chamber being large enough in that case to offer little obstruction to
the passage of the gaseous products from one part to the other, where,
however, a much lower temperature in the second chamber is desirable.
The aperture from the furnace proper should be much contracted, and
the escape from the second chamber left almost free, such second
chamber will be useful for melting spiegel eisen to be added to the
molten metal and determine the state of carburation of the steel
obtained by fusion in such furnaces; or the second chamber may be
employed to heat scrap or other malleable metal to be afterwards
added to any partially decarburized pig iron in the hearth of the furnace
proper.
One of the forms or modifications of melting furnace which con-
stitutes a part of my present improvements, and partakes both of the
cupola and reverberatory character of furnace combined in one, that is,
the fire chamber consists of an upright cylinder, to which both the fuel
and the malleable iron or steel to be melted are supplied, thus occupying
one common chamber, as in the fixed reverberatory furnace described
in my former Patent for high-pressure furnaces, dated the 10th day of
November 1868; the lower part of the furnace, instead of forming a
receptacle for the fused. metal, is slightly inclined to one side, and at
the foot of this incline one or more openings are made leading direct

page_text: into a shallow hearth covered by a low reverberatory arch or roof, the
small exit aperture for the escape of the gaseous products of combustion
being at the end of the hearth farthest from the cupola part of the
furnace. By this arrangement the metal as it fuses will flow down the
inclined bed of the cupola and run into the hearth; the flame and
heated products of combustion will also pass into this compartment of
the furnace through the openings before named, and heat the metal as
it accumulates there. By this means the tendency of the molten metal
to become too much carburized in the bed of the cupola will be pre-
vented. In order to promote the combustion of the fuel in the upper
part of the cupola a portion of the products of combustion may also be
allowed to escape from the upper portion of it.
My Invention also consists in certain other modifications of the
high-pressure cupola furnace employed for the fusion of malleable
iron or steel. I make the furnace sufficiently high to contain the whole
or a greater part of the charge of fuel and metal, which may be charged
on at once, and the upper part of the furnace be then closed with
a suitable door and fastened down until the complete fusion of the
charge of metal is effected. I prefer to form a contracted part in such
furnace, gencrally termed the boshes, at a small distance above the
tuyeres, so as to prevent the charge of materials pressing in an un-
broken column on the bottom of the furnace or on the molten metal
contained there. In order to prevent an undue amount of carburation
of the metal consequent on the height of the column of materials in the
furnace a small quantity of air or steam is allowed to flow through a
suitable valve into the upper part of the furnace and find its way down-
wards to the small escape apertures which are situated between the
boshes, and hence there will be no ascent of heated carbonic oxide gas
to act on and carburize the metal in the upper part of the furnace. The
tuyeres which supply blast under high pressure, as well as the escape
aperture or apertures are each below the boshes or contracted part. In
some cases the tuyeres are at the lower level, and in other cases they
may be at the higher level, and the escape apertures only a little above
the surface of the fluid metal when a full charge is collected in the
hearth, suitable flues being provided to conduct the products of com-
bustion away, the regulation of the pressure being effected by a restricted
escape aperture, as described in my former Patent, dated November
10th, 1868, and herein-before referred to.

page_text: In some cases I contract the exterior casing of the furnace at the
boshes, and I then make the escape apertures open upward at this part.
For the better regulation of the pressure of the gaseous products of
combustion in high-pressure melting furnaces I employ a mercurial
gauge. The gases of the furnace have access to an iron pipe of about
one inch in diameter, which is connected with the cistern containing
the mercury which supplies the glass gauge, and in order to prevent
the mercury from becoming unduly heated I conduct by means of a
very small pipe and cock a current of air from the main blast pipe into
the iron pipe first named, the jet entering it at about a foot above the
level of the mercury, the air in the main blast pipe will always be at a
somewhat higher pressure than the gaseous matters in the furnace, so that
a gentle current of cold air will constantly pass up the pipe first named
into the furnace, and so prevent the flame and hot gases from ever
descending into the mercury cistern. The flow of air by the small pipe
is too gentle to sensibly alter the pressure indicated by the mercurial
column in the ordinary glass tube. The state of the furnace, and the
operations going on in its interior may be seen by making one or more
eye holes" of a conical form through the lining of the furnace, the
outer end having a piece of stout plate glass forming a sort of eye piece
fitted to it, and being also provided with a small pipe and cock, by
which.compressed air may enter in front of the eye piece, and prevent by
its motion in an opposite direction the passage of sparks or flame up the
conical aperture through which the sight is directed, thus keeping the
glass cool and free from injury.
$5
It has been found that the escape of a large body of flame and heated
products of combustion from furnaces working under compression,
as described in my former Patent, dated 10th of November 1868, and
before referred to, produces such a loud and continuous roar as to
prevent the workmen attending to it from hearing any directions given
to them when standing near the furnace while in blast. I have, how-o
ever, found that this inconvenience is prevented or very much lessened
by uniting a tube or flue to the mouth of the escape aperture, or to the
parts adjacent, so that the escaping flame and gases are thereby cut off
from immediate contact or communication with the surrounding atmo-
sphere of the room or building in which the furnace is worked. For this
purpose I employ an iron pipe lined with bricks and form a cross branch
therefrom, either fixed or moveable, so as to be readily connected or

page_text: disconnected from the furnace; this lined pipe may either pass under-
ground or be directed at once upward through the roof of the building.
I prefer to give the pipe a taper form, so as to allow the gases to
expand gradually before their final exit into the atmosphere. In some
cases it may be found desirable to form the restricted escape aperture
at the outer end of this pipe, instead of forming it at a point immediately
adjoining the furnace.
I sometimes make the escape orifices of high-pressure furnaces in a
metal block or plate having a water passage formed in the metal around
the orifice, through which water is made rapidly to flow, so as to keep
the orifice cool.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Bessemer in the Great Seal Patent
Office on the 10th November 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Queen Street Place, Cannon Street, in the City of London,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of May, in the year of
our Lord One thousand eight hundred and sixty-nine, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Henry Bessemer, Her special
licence that I, the said Henry Bessemer, my executors, adminis-
trators, and assigns, or such others as I, the said Henry Bessemer, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF MALLEABLE IRON AND STEEL, AND IN FURNACES AND APPARATUS
EMPLOYED FOR THEIR FUSION AND TREATMENT," upon the condition (amongst
others) that I, the said Henry Bessemer, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands
and seals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed,

page_text: and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Henry Bessemer, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, that is to say:-
These improvements relate to the fusion of malleable iron and steel
and other carburets of iron in furnaces in which the gaseous products of
combustion are retained under a pressure exceeding that of the external
atmosphere, as in the high-pressure furnaces described in a Patent
granted to me, and bearing date the 10th day of November 1868, and
numbered 3419.
The improvements constituting my present Invention consist,-
Firstly. In certain modified forms of the reverberatory furnace, and in
each and every of such modifications I employ an outer shell or casing con-
structed of plates of iron or steel securely rivetted together, or of cast iron
secured by hoops, bolts, or ties of malleable iron or steel; the shell in
either case being well caulked and rendered air-tight at all laps and
joints, and of sufficient strength to resist safely an internal pressure of
one or more atmospheres in excess of the external atmospheric pressure,
as set forth in the Patent herein-before referred to. The lining of all
such modified form of furnaces may be made with fire-brick, plumbago,
or ganister, or other refractory materials, and the tuyeres for conveying
a blast of air therein may also be made in the manner set forth in the
Specification of my former Patent, before referred to.
In one modification of the furnaces so constructed I form a feeding
chamber for the supply of metal to be melted of the whole or nearly
the whole breadth of the hearth of the furnace, from which it rises
vertically near that part usually called the fire-bridge. I prefer it to be
a rectangular chamber sufficiently large to contain the whole or greater
part of the charge of the metal to be melted at one operation. It may
be lined with brickwork, or in a similar manner to the rest of the
furnace, and at top may have a door through which the metal is put in,
and which is then closed by a simple metal fitting, which may be pro-
tected from the effects of heat by the leakage inward of air or steam,
or the iron door lined with fire-brick may be luted with lime or clay
slip, and be secured against the internal pressure by cottered studs, or

page_text: by bolts and nuts, or by any other suitable and convenient mode of
fastening. The fire-chamber may be circular or D-shaped, the straight
side of the D being next the hearth. I prefer to make a low roof to
such furnace in order to keep the flame well down upon the metal in the
hearth when melted. The escape aperture being at the end of the
furnace furthest from the fire-chamber the flame and heated matters will
have to pass through the interstices of the loose heap of scrap or other
metal which descends from the feeding chamber' and intercepts the free
passage of the flame to the exit aperture. As the lower part of the mass
fuses the remainder of the metal sinks down and takes its place until
all is fused.
And in order that the mode of constructing such furnaces may be
fully understood, I have represented the same on Sheet A. of the
Drawings hereunto annexed, where Figure 1 represents a vertical lon-
gitudinal section on the line A, B, of Figure 3, and Figure 2 a vertical
cross section on the line C, D, of Figure 1; a horizontal section is also
shown at Figure 3, in all of which Figures the same letters of reference
are used to indicate a repetition of the parts shewn.
The outer shell a of the furnace is composed of stout plate iron or
steel securely caulked and rivetted; b is the lining of fire-brick, ganister,
or other refractory material. The fire-chamber c may be of a circular
form having a groove or hollow across the lower part to facilitate the
running out of the fluid slags produced by the fusion of the impurities
of the fuel at a suitable tap hole, not shown; such fusion being assisted
by the use of lime as in ordinary cupola furnaces. The upper part of
the fire-chamber has an opening at c* for the admission of fuel, this
opening is closed by a fire-tile d fitted to a metal ring or case e, and is
forced down upon the upper iron ring of the furnace by means of a
compound screw arrangement actuated by the handles g, the whole of
which apparatus at the time of putting on a fresh supply of fuel is
moved on one side on the axis or crane post h. The cooling of the
metal ring by the circulation of water, and the prevention of the
escape of heated gases at the junction of the rings e and f being pre-
vented by a blast of air conveyed into the annular passage e*. The
whole of the arrangements of the feeding door, its screw apparatus,
crane post, feeding cylinder, and circulation of air and water being
precisely the same as described in a former Patent granted to me, and
bearing date the 10th day of November 1868, and numbered 3419, and

page_text: therefore of itself forms no part of my present Invention. The com-
bustion of coke or other fuel in the fire-chamber c is kept up by forcing
in a blast of air under considerable pressure at the tuyeres i, i. These
tuyeres are formed by preference of burned fire-clay, and are caulked at
their outer ends into the iron frames j, and are held in place by the
cross arms k, by which the blast pipes are screwed up and held in
close contact with the end of the tuyeres; m is a vertical rectangular
chamber tapering from the top downwards, it is covered by a fire-tile n
let into an iron frame o, and is held firmly in place by cotter bolts, which
pass upward from the iron ring p, the latter being securely rivetted to
the outer casing a* of the rectangular chamber m; two loops q, q, arc
provided for lifting off the cover by a small crane or lever; when the
furnace is well heated the frame or cover o is removed, and the charge
of metal to be melted is introduced, as shown at r, the lower portion
resting on the inclined slope of the furnace hearth; the cover is put on
and cottered down, a little clay or lime luting having first been smeared
over the surfaces coming in contact; a powerful blast is then forced
through the tuyere i into the fire, the flame and heated gaseous pro-
ducts of combustion passing through the interstices of the scrap metal
at 1, and passing over the bath where the fused metal accumulates at s,
and finally escapes at the small opening t, the size of this opening being
such as to prevent the free escape of the gases, penning them back until
the pressure within the furnace rises by preference from 10 to 30 lbs. per
square inch in excess of the pressure of the external atmosphere, whereby
the temperature of the products of combustion will be greatly increased,
and the fusion of the malleable iron or steel readily effected; the mass
sinking down and leaving the chamber m as the fusion goes on until the
whole is collected in a fluid state in the hearth s, into which some spiegel
eisen, or other carburet of iron may be run, or either of these carburets
of iron may be charged into the hearth at the time of commencing the
melting operation. When the metal is at the most advantageous
temperature for forming into ingots or castings it may be drawn off at a
tap hole as usual in reverberatory furnaces.
In the second modification I omit the feeding chamber, and in licu
thereof I make a feeding door at the end furthest from the fire-chamber,
using by preference a nearly flat shallow hearth. The scrap, wrought,
or malleable iron and steel, or other kind or quality of metal I make
into small piles on a board or tile, or on pieces of plate metal, or crop

page_text: ends of rails. I introduce these piles on a peel or shovel, commencing
to pack them first near the fire-bridge in rows near each other until the
whole charge is put in. I prefer that a space be left beneath the piles,
which may be for that purpose propped up on wood, brick, or metal
pieces, so as to allow the flame to pass under, between, and over the
piles, well heating the hearth and the lower part of the piles before
fusion takes place. The escape apertures I prefer to make one on each
side of the furnace, or to make one only at the top or roof near the
feeding door or in the feeding door itself. This modification of the
furnace is represented on Sheet B. of the annexed Drawings, where
Figure 1 is a longitudinal vertical section on the line A, B, of Figure 3;
Figure 2 is a vertical cross section on the line C, D, of Figure 1, and
Figure 3 a plan in section; in all of which Figures the same letters of
reference are employed to denote a repetition of the parts shown.
a, a, is the outer case or shell of the furnace of stout plate iron or steel
securely caulked at all jomis; o, the lining of fire-bricks, ganister, or
other refractory material. The fire-chamber c is made somewhat
D-shaped, as shown in Figure 3, the flattened side being formed by the
fire-bridge d. The arrangements for the supply of fuel, including fire-
door, screw apparatus, crane arm, feeding cylinder and passages for
escape of air and circulation of water are similar to those described in
reference to the furnace shown on Sheet A. of the Drawings annexed,
the details of which arrangement are also more fully described in my
former Patent of the 10th day of November 1868, and numbered 3419,
and herein-before referred to; but in lieu of employing the vertical
feeding chamber, as shown on Sheet A., I introduce the metal to be
fused at the fire-door at the end of the furnace. This fire-door consists
of a stout iron frame e dovetailed internally for the purpose of retaining
in place the fire-tile f, which is moulded with a central conical hole g,
forming the escape, opening for the compressed gaseous products of com-
bustion; a plate h is rivetted to the frame e, through which cotter bolts
pass for the purpose of securing the fire door firmly on to the end of the
furnace. The door so constructed may be removed by a small swing
crane, and when the workman has placed the piles of scrap or other
metal m evenly over the hearth the door is luted and cottered on to its
seat; the blast is then applied until fusion is effected, as before described
in reference to the furnace shewn on Sheet A.
In the third modification of the reverberatory furnace I make the

page_text: whole of the roof moveable, so that by means of an overhead crane the
metal shell of the furnace roof and the lining of that part may be readily
removed by loosening a series of cottered studs or bolts and nuts. This
roof may be replaced by another while the former one is 'undergoing
repair. The joint where the roof unites with the other portion of the
furnace being rendered sound and air-tight by a mixture of three to six
parts of ganister to one of fire-clay made into the consistency of mortar,
and evenly spread between the flanges. The bath and fire-chamber may
by the removal of the roof be quickly cooled down and repaired. I
prefer to line the roof and other parts of the furnace with a much less
thickness of lining than is usual in reverberatory furnaces, and to cool
the external shell of such furnaces by a close or open jacket, through
which water flows. For the lining (if made thin enough) to allow
some of the heat absorbed by it to escape outwardly, and in consequence
to prevent the lining rising to a destructive temperature, thus by the
loss of a little heat a much greater durability will be given to the furnace
lining.
In cither of the modifications of the reverberatory furnace, before
described, the fire may be made in a well or chamber with coke, a blast
of air being introduced at several tuyeres. The furnace door may also
be closed in each case in the manner described in my former Patent of
the 10th of November 1868, and herein-before referred to, in which
case it is desirable to obtain a greater length of flame than can be
obtained from the combustion of coke alone. I therefore when not
employing a liquid hydrocarbon for that purpose prefer to employ pul-
verized coal in a fine granular state, or completely reduced to fine
powder. I introduce the coal into the blast pipe by means of a small
wheel having radial blades, which fit accurately into a race or groove,
the blades projecting into the blast pipe, so that the blast may carry
forward the coal at the speed at which the wheel delivers it. I prefer
to make the blast pipe so small in diameter as to insure a powerful
current between the feed wheel and the tuyeres. The coal powder may
thus be forced in among the lumps of incandescent coke in any desired
proportions, or the coal powder may be burned in a suitable chamber
alone as now practised in other furnaces. This mode of feeding coal
powder into furnaces working under high pressure is represented in
section at Figure 5, Sheet D., of the Drawings hereunto annexed, where
P represents the main blast pipe leading to the furnace in the direction

page_text: indicated by arrows. On the upper side of the pipe a chamber is formed,
in which the wheel Q is fitted, having an axis R, which passes through
the sides of the chamber T, and is there connected by a strap or wheels
to any first mover. The chamber above the wheel Q may be enlarged
upward so as to contain as much coal powder as will be required during
the fusion of a charge of metal. A close cover is screwed on to the
chamber T, and a small pipe leading from the blast pipe P enters the
upper part of the chamber T for the purpose of equalizing the pressure
of air above and below the wheel Q, which in revolving takes in as much
powder between its radial blades as fills the cavity formed between them
and the race in which it works; as the wheel revolves the spaces are
filled with coal powder, and on descending into the pipe P the blast
carries the powder forward in a dense cloud along the pipe into the
furnace, where the volatile parts are instantly converted into combustible
gas, and becoming ignited produce a powerful flame.
In lieu of this mode of burning coke and coal mixed or coal alone in
the form of powder, I construct the reverberatory furnaces after either
of the modifications herein-before described, except in so far as the
fire-chambers thereof are concerned, using in lieu thereof a fire-grate
and ash-pit made after the manner of the fire-grates of ordinary rever-
beratory or puddling furnaces, such fire-grate and ash-pit being arranged
with a suitable door or slide so as to allow the ash-pit to be cleaned out
when required, and be closed air-tight or sufficiently so for the purposes
of my Invention; and in which furnace I am enabled to burn the
ordinary furnace coal used in reverberatory furnaces. I also make a
door or slide in order to gain ready access to the fire-bars, so that the
workman may remove the clinkers and adjust or remove a fire-bar if
necessary. When using a fire-grate I prefer to introduce the air for
combustion in a diffused state through numerous openings into the ash-
pit; and I also prefer to employ a chimney with an opening leading
from the after part of the furnace into it in addition to the restricted
opening, through which alone the gaseous products of combustion pass
while the furnace is working under high pressure. With a furnace
so arranged I am enabled to first heat the hearth and body of the furnace
and the piles of metal to be fused therein by using the chimney draught,
the doors in the ash-pit being open, so that the metal may be heated up
to a welding heat without a forced blast. The fire may then have fresh
fuel put on to it, and all doors securely closed and the blast applied,

page_text: using by preference a very high pressure for a short time, so as to rapidly
fuse the charge of heated metal and give it a high temperature. During
the open furnace heating there will be generally a tendency to oxidise
the metal somewhat, so that by this mode of working a very mild metal
may be obtained or a proportionably large quantity of pig or other
carburet of iron may be combined with it.
In reverberatory furnaces in which these improvements are used white
or grey pig iron may be melted on the hearth (slowly if desired) or it
may be supplied in a molten state to the furnace, and in either case be
more or less decarburized by the action of free oxygen passing over it
along with the furnace gases; the pressure may then be put on and the
heat increased, and the scrap or other malleable metal forming part of
the charge be fused and incorporated with the partially decarburized
pig iron so employed; a blast of air to facilitate the decarburation of
the metal may be let in at the fire-bridge or at the feeding door, and
so also red ore or other oxidising materials may be employed with the
charge of pig metal to facilitate its decarburation.
And in order that the mode of constructing furnaces with a moveable
roof or arch, and capable also of burning coal and working with an
ordinary chimney draught at one stage of the melting process, and
under great pressure at another stage may be fully understood, I have
shown on Sheet C. of the Drawings hereunto annexed a furnace in which
these several objects may be obtained, Figure 1 being a longitudinal
vertical section of the furnace and flue, as arranged for working with a
chimney draught, and Figure 2 shows the same when working under a
pressure considerably above that of the external atmosphere, and Figure
3 is a side elevation of the same; Figure 4 is an end elevation, the
chimney being removed in order that the arrangement of flues may be
more clearly shown; Figure 5 is a vertical cross section on the line A, B,
of Figure 1, and Figure 6 an elevation of that end of the furnace where
the fire chamber is situated; all letters of reference on Sheet C., when
repeated, indicate a repetition of the same parts.
a is the outer shell of the furnace formed in part of stout plate iron or
steel rivetted and caulked, the cast iron end plates a* being also firmly
secured to the rest of the shell so as to prevent the escape of any heated
gaseous matters at the joints; the furnace lining 6 is composed of fire-
bricks, ganister, or other refractory materials usually employed in iron
melting furnaces; c is a rectangular fire chamber, the fuel resting on

page_text: wrought-iron fire-bars d supported on wrought-iron bearers e; the ends
of these bearers pass through the flat sides of the shell a at e* and serve
as stay rods to support them; an additional stay rod f is also shewn
passing through the ash-pit g; the fire-bridge 6* has a water tube h
passing through it to keep the brickwork from being overheated. The
hearth m of the furnace is nearly flat at bottom sinking only as it
approaches the tap hole n. The moveable roof or arch of the furnace a
is made of strong steel or iron plates further stiffened by T ribs a³, the
stout angle flanges a' forming a skewback for the lining of bricks b², and
serving also to secure the moveable arch to the other portion of the
furnace by means of the cottered studs i, i; these studs or bolts pass
through the massive flange a to which the lower portion of the furnace
shell is rivetted, the ends of the moveable roof or arch being secured in
a similar manner, so that at any time when necessary the cotters i can
be withdrawn, and by means of an overhead crane the roof of the furnace
may be removed and fresh lined, its removal also affording great facility
for repairs of the fire chamber and shallow hearth, which would other-
wise be almost inaccessible; the junction of the moveable roof with the
other part of the furnace is rendered air-tight by a luting of fire-clay or
lime; at the hearth of the furnace narrows terminating at j* in a
circular opening, through which the piles k or other pieces of metal to
be melted are introduced to the furnace; at this part the cast-iron end
plate a* of the furnace is also circular in form having a hollow channel
7. formed around it; into this channel air under pressure may be admitted
by the pipe and cock o, the face of the channel nearest the flue is
turned truly, and is perforated with numerous small holes *, as shown,
for the purpose of conducting air into the channel formed on the sliding
ring s, so that when the furnace is working under pressure the escape
of compressed air between the surfaces of the rings and face plate a*
will prevent the passage outward of the heated gaseous products of com-
bustion by reason of the pressure of the air conveyed by the pipe l
exceeding the pressure of such gases.
In order to change the working of the furnace from the ordinary
chimney draught to high pressure I employ the double moveable flues
A and B mounted on an axis C, which is supported by brackets D
bolted to the under side of the floor plates E; the flues A and B are
formed of rivetted plate iron lined with segmental fire-bricks F. On
one end of the flue tube A is the flange A*, and on the tube B a similar

page_text: flange B*, both of which are for the purpose of forming a joint with the
iron hoop G, which is fitted on to a ring of brickwork H projecting from
the chimney H*; at the opposite end of the flue tubes are sliding rings s,
one side of them is provided with a semicircular groove as before named,
and the opposite side is formed into a series of inclined surfaces, see s*,
Figure 3; these inclined surfaces are fitted to similar ones formed on the
edge of the hoops u, which are rivetted on each of the flue tubes A and
B, by inserting a lever in the hole the ring s may be moved round,
and by means of the inclined surfaces will be forced in close contact
with the face of the channel r. The flues A and B are mounted on an
iron frame w through bosses in which the axis C passes; between the
lower ends of the frame wa counterweight y is fixed for the purpose
of balancing the double flue tubes and admitting of their easy move-
ment on their axes, the weight by preference being somewhat greater
than the flues, in order to keep them in an erect position. z is a pit
below the floor plates for the counterweight y to move in, slots being
made in the plate E to allow the movement of the frame w. The length
of the flue tubes should be such as to afford ample space between the
furnace and chimney for the workmen to stand when charging on the
metal. When these tubes are moved on one side, as seen in Figure 4,
where the opening j* is shown uncovered and readily accessible to the
workman, so soon as the piles or other pieces of metal to be melted are
introduced through the opening j*, the workman will move the flue
tube A opposite the opening j* and tighten it up by turning round the
rings with a lever, as described; this will bring the apparatus into the
position shewn in Figure 1, and establish a free communication between
the fire chamber c and the chimney H*. The ash-pit g is supplied
with air through the open door L moved by the handle M; this door fits
against a truly surfaced face formed on the inside of the end plate a*, so
as to keep it air-tight when required; the fire is supplied with fuel through
the opening c*, which at other times is closed by a door N, which slides
horizontally by means of the handle O, shown in Figure 6; the back
part of the door fits accurately to the faced surface of the plate a*; a
fire-tile N✶ shields the iron door from the too powerful action of the
radiated heat of the fire. The ashes may be removed at the end of the
day's work by removing the plate P at the lower part of the ash-pit.
The action of the furnace will be as follows:-The several moveable
parts referred to being in the position shewn in Figure 1, the workman

page_text: will keep up the fire by ordinary chimney draught, clearing his fire-bars
from time to time through the open door L, and supplying coal or other
fuel from time to time, as required, through the fire-door N and
opening *, the very low roof of the furnace will keep the flame well
down upon the metal, and if arranged in piles mounted on the crop ends
of rails, as shewn, or on other pieces the flame and heated matters will
pass along the surface of the hearth beneath the piles and greatly raise
its temperature, while the piles will be completely enveloped in the flame
and be rapidly brought up to a welding heat; as soon as this tem-
perature, is arrived at the workman will charge on a good supply of fuel
and immediately proceed to close the door L, stopping all access of air
to the ash-pit through this opening; he will then slacken the ring s and
push over the flue tubes until he brings the tube B opposite the
opening *; he will next tighten the joint by moving the ring s, turn
on air through the cock o and channel r, the position of the several
parts of the furnace then being, as shewn in Figure 2, he will open a
large sluice valve, not shewn in the Drawings, whereby a blast of aid
under pressure (of 20 to 50 lbs. per square inch by preference) will pass
up the pipe Q, and through the numerous perforations shewn, and will
diffuse itself throughout the ash-pit and pass up through the fire-bars,
the whole of the gaseous products in the interior of the furnace will be
thus brought up to a pressure nearly equal to that of the blast in con-
sequence of the outlet to the chimney in the tube B being greatly
diminished, as shown at R. This outlet is formed in a piece of well-
burned fire-clay R*, and can be readily replaced when worn out; the
opening R may be of about one square inch area for every square foot
area of fire-grate; but this will depend on the pressure at which the
furnace is to be worked. The gaseous products of combustion being
thus prevented from expanding freely will retain in this dense form an
extremely high temperature, which acting on the previously highly heated
metal will rapidly bring it to a state of fusion, after which it may be run
off at the tap hole n, and be mixed with molten spiegel eisen, as is well
understood in steel making, or the spiegel eisen or other pig, or carburet
of iron or alloy of iron may be put into the furnace and there fused and
form part of the charge.
Another improvement in reverberatory and other furnaces working
under high pressure consists in forming a second heating or melting
chamber, into which the flame and heated gaseous products of com-
bustion from the furnace proper are allowed to flow, the second chamber

page_text: being provided, by preference, with the restricted escape aperture, the
passage or opening leading from the furnace proper to the second
chamber being large enough in that case to offer little obstruction to
the passage of the gaseous products from one part to the other; where
however a much lower temperature in the second chamber is desirable
the aperture from the furnace proper should be much contracted, and
the escape from the second chamber left almost free, such second
chamber will be useful for melting spiegel eisen to be added to the
molten metal, and determine the state of carburation of the steel
obtained by fusion in such furnaces; or the second chamber may be
employed to heat scrap or other malleable metal to be afterwards added
to any partially decarburized pig iron in the hearth of the furnace proper.
The second or heating chamber to high pressure melting furnaces will
vary in size and form, both with regard to the kind of furnace to which
they may be applied, and also to suit the purpose to which they may be
required.
One of the forms or modifications of melting furnaces which con-
stitutes a part of my present improvements, partakes of the cupola and
reverberatory character of furnace combined in one, that is, the fire
chamber consists of an upright cylinder, to which both the fuel and the
malleable iron or steel to be melted are supplied, thus occupying one
common chamber, as in the fixed cupola furnace described in my former
Patent for high-pressure furnaces, dated the 10th day of November 1868,
the lower part of the furnace instead of forming a receptacle for the
fused metal is slightly inclined to one side, and at the foot of this incline
one or more openings are made leading direct into a shallow hearth
covered by a low reverberatory arch or roof, the small exit aperture for
the escape of the gaseous products of combustion being at the end of the
hearth farthest from the cupola part of the furnace; by this arrangement
the metal as it fuses will flow down the inclined bed of the cupola and
run into the hearth, the flame and heated products of combustion will
also pass into, this compartment of the furnace through the openings
before named, and heat the metal as it accumulates there.
By this
means the tendency of the molten metal to become too much carburized
on the bed of the cupola will be prevented. In order to promote the
combustion of the fuel in the upper part of the cupola a portion of the
products of combustion may also be allowed to escape from the upper
portion of it.

page_text: And in order that this modification of the high-pressure melting
furnace may be fully understood, I have shewn on Sheet D. of the
Drawings hereunto annexed, a longitudinal vertical section of the same
at Figure 1, and a cross section at Figure 2, taken on the line A, B, of
Figure 1, from which it will be seen that the upper part
of the
cylindrical fire chamber a is provided with a door and screw apparatus
for closing it against the internal pressure arranged with cooling passages
and supply of air under pressure to the joint in precisely the same
manner as herein-before described in reference to Figures 1 and 2 on
Sheet A. of the annexed Drawings, and more fully described in a Patent
granted to me, and bearing date the 10th day of November 1868, and
numbered 3419; the shell b of the furnace, the lining c, and the arrange-
ments of the fire-clay tuyeres h being also constructed in the manner
described in the last-mentioned Patent, and consequently of themselves
form no part of my present Invention, which in this case consists simply
in combining the reverberatory roof d and hearth e with the cupola
fire chamber a, whereby the metal fused in the chamber a instead of
accumulating in the lower part of that chamber and being there exposed
to the carburizing action of the incandescent fuel runs down as soon as
it is melted into the reverberatory hearth e, the heated products of
combustion passing over it on their way to the escape aperture f, which
is so small as to pen back the gaseous products of combustion until a
considerable pressure is obtained; a portion of these gases may be
allowed to escape also by the small opening g near the top of the
chamber a.
My Invention also consists in certain other modifications of the high-
pressure cupola furnace employed for the fusion of malleable iron or
steel. I make the furnace sufficiently high to contain the whole or a
greater part of the charge of fuel and metal which may be charged on
at once, and the upper part of the furnace be then closed with a suitable
door and fastened down until the complete fusion of the charge of metal
is effected. I prefer to form a contracted part in such furnace, generally
termed the boshes, at a small distance above the tuyeres, so as to prevent
the charge of materials pressing in an unbroken column on the bottom
of the furnace or on the'molten metal contained there. In order to
prevent an undue amount of carburation of the metal consequent on
the height of the column of materials in the furnace, a small quantity of
air or steam is allowed to flow through a suitable valve or opening into

page_text: the upper part of the furnace, and find its way downwards to the small
escape apertures, which are situated below the boshes, and hence there
will be no ascent of heated carbonic oxide gas to act on and carburize the
metal in the upper part of the furnace. The tuyeres which supply blast
under high pressure, as well as the escape aperture or apertures, are
each below the boshes or contracted part; in some cases the tuyeres are
at the lower level, and in other cases they may be at the higher level,
and the escape apertures only a little above the surface of the fluid metal
when a full charge is collected in the hearth, suitable flues being
provided to conduct the products of combustion away, the regulations
of the pressure being effected by a restricted escape aperture, as
described in my former Patent, dated November 10th, 1868, and herein-
before referred to. In some cases I contract the exterior casing of the
furnace at the boshes, and I then make the escape apertures open
upward at this part.
And in order that this mode of constructing high-pressure cupola
melting furnaces may be fully understood, I have shewn a vertical
section of one at Figure 3 on Sheet D. of the annexed Drawings, where
a represents the rivetted iron shell lined with fire-brick or other
refractory material b; the opening c is for the admission of fuel, and
the metal to be fused, a full charge is put on at once, and the door or
cover is cottered down with a little lute in the joint to prevent escape
of air; the blast to support combustion is supplied by the tuyeres g,
which are arranged in the manner herein-before described and referred
to. Below the contracted part or boshes the escape apertures h are
situated so that the combustion of the fuel is for the most part or wholly
confined to the lower portion of the furnace, the materials falling into
the lower part of the furnace as the fusing of the metal and combustion
of the fuel goes on, a small quantity of air or steam being admitted at
the opening i to prevent the ascent of carbonic oxide among the pieces
of unfused metal; by this mode of working a whole charge at once the
labour and loss of time consequent on feeding in successive charges of
metal and fuel are avoided.
For the better regulation of the pressure of the gaseous products of
combustion in high-pressure melting furnaces, I employ a mercurial
gauge, the gases of the furnace have access to an iron pipe of about
one inch in diameter, which is connected with the cistern containing the
mercury which supplies the glass gauge, and in order to prevent the

page_text: mercury becoming unduly heated, I conduct by means of a very small
pipe and cock a current of air from the main blast pipe into the iron
pipe first named, the jet entering it at about a foot above the level of
the mercury, the air in the main blast pipe will always be at a some-
what higher pressure than the gaseous matters in the furnace, so that a
gentle current of cold air will constantly pass up the pipe first named
into the furnace, and so prevent the flame and hot gases from ever
descending into the mercury cistern. The flow of air by the small pipe
is too gentle to sensibly alter the pressure indicated by the mercurial
column in the ordinary glass tube.
A mercurial gauge so constructed is shown at Figure 4 on Sheet D.,
where A is the mercury cistern secured to the shell B of the furnace;
C is a large iron pipe communicating with the interior of the furnace
at C* at its upper end, and with the mercury cistern at its lower end;
E is the glass tube, and F the scale of inches, showing the amount
of pressure in inches of mercury, a small pipe H leading from the main
blast pipe enters one side of the pipe C above the mercury and allows
cncugh cold air under pressure to pass up the pipe C into the furnace as
will prevent the hot furnace gases descending to the mercury, the
quantity of air admitted is so small compared with the capacity of the
pipe C as not to sensibly alter the indicated pressure, but it nevertheless
effectually protects the mercury from the intensely heated gases of the
furnace. The state of the furnace and the operations going on in its
interior may be seen by making one or more "eye holes" of a conical
form through the lining of the furnace, the outer end having a piece of
stout plate glass forming a sort of eye piece fitted to it, and being also
provided with a small pipe and cock by which compressed air may enter
in front of the eyc piece and prevent by its motion in an opposite
direction the passage of sparks or flame up the conical aperture through
which the sight is directed, thus keeping the glass cool and free from
injury.
The mode of constructing the peep hole is shown at Figure 6, Sheet D.,
which represents a section of a portion of the shell and lining J of a
high-pressure furnace taken through the centre of the peep hole. K is
an iron ring with an annular passage L formed in it; into this passage
air is conducted by a small, pipe from the main blast pipe; numerous
small holes are drilled into this passage for the escape of air into the
centre part; a piece of blue giass M is..held.in place by the plate N;
through this glass.the sight is directed, and also through the fire-clay

page_text: cone O, which is bricked into the lining of the furnace; through such
an opening the fusion of the metal may be observed without difficulty
from time to time as the operation proceeds, the current of air keeping
the glass cool and preventing its being obscured by smoke and dust.
It has been found that the escape of a large body of flame and heated
products of combustion from furnaces working under compression, as
described in my former Patent, dated the 10th of November 1868, and
before referred to, produces such a loud and continuous roar as to
prevent the workmen attending to it from hearing any directions given
to them when standing near the furnace while in blast; I have,
however, found that this inconvenience is prevented or very much
lessened by uniting a tube or flue to the mouth of the escape aperture,
or to the parts adjacent, so that the escaping flame and gases are thereby
cut off from immediate contact or communication with the surround-
ing atmosphere of the room or building in which the furnace is worked.
For this purpose I employ an iron pipe lined with bricks, and form a
cross branch therefrom, either fixed or moveable, so as to be readily
connected or disconnected from the furnace; this lined pipe may either
pass underground or be directed at once upward through the roof of the
building. I prefer to give the pipe a taper form, so as to allow the gases
to expand gradually before their final exit into the atmosphere. In
some cases it may be found desirable to form the restricted escape
aperture at the outer end of this pipe instead of forming it at a point
immediately adjoining the furnace. The flue tubes shown on Sheet C
of the annexed Drawings for connecting the escape aperture of the
furnace with the chimney effectually checks this unbearable noise, and
by their ready movement admit free access to the escape aperture when
required.
I sometimes make the escape orifices of high-pressure furnaces in a
metal block or plate having a water passage formed in the metal around
the orifice, through which water is made rapidly to flow so as to keep
the orifice cool. This mode of constructing the escape openings of high-
pressure furnaces is shown at Figure 7 on Sheet D., where 7 represents
a portion of the furnace plate and lining s. A wrought iron or cast
steel plate t is bolted to the plate r, and is formed with an annular
passage u for the circulation of cold water supplied by the pipe and
carried off by the pipe w, the metal escape hole is preferable, being less
likely to alter in size than fire-clay outlets.

page_text: Having described my Invention, and the manner in which the several
parts thereof may be carried into practical operation, I desire it to be
understood that I do not confine myself to the precise details given, so
long as the peculiar character thereof be retained; but I claim as my
Invention of improvements in the manufacture of malleable iron and
steel, and in furnaces and apparatus employed for their fusion and
treatment
Firstly. The employment of a vertical feeding chamber for supplying
scrap or other decarburized or uncarburized malleable iron or steel to
reverberatory furnaces, where its fusion takes place under high pressure
of confined gaseous matters.
Secondly. The arranging piles of scrap or other malleable iron or steel
raised on supports on the hearths of reverberatory furnaces, in which
the fusion of the metal is effected under high pressure of gaseous matters
confined therein, and the forming such furnaces with a feeding door at
their ends to facilitate the introduction of such piles.
Thirdly. The constructing reverberatory high-pressure furnaces em-
ployed for the fusion of scrap or other decarburized or uncarburized
malleable iron or steel, with a moveable roof or arch.
Fourthly. The cooling the outer shell or iron casing of reverberatory
high-pressure furnaces employed for the fusion of scrap or other decar-
burized or uncarburized malleable iron or steel by water circulating in
contact therewith.
Fifthly. The construction and employment of reverberatory furnaces
for the fusion of scrap or other decarburized or uncarburized malleable
iron or steel in such manner as to admit of fuel being burnt on fire-bars
by ordinary chimney draught at the commencement of the process, and
also to admit of the fuel being burnt under a high pressure of confined
gaseous matters towards the close of the fusing operation.
Sixthly. The employment of a moveable double flue tube for changing
the draught and opening the feed hole of furnaces employed for the
fusion of scrap or other decarburized or uncarburized malleable iron or
steel for the purpose of obtaining ingots or other masses of malleable
iron or steel.
Seventhly. The decarburation or partial decarburation of molten pig
or other carburet of iron on the hearths of reverberatory furnaces, and
the subsequent fusion of scrap or other decarburized or uncarburized

page_text: malleable iron or steel therein under the pressure of confined gaseous
matters for the purpose of obtaining malleable iron or steel by their
union.
Eighthly. The general arrangement and combination of the several
parts constituting the improved melting furnace represented on Sheet C.
of the annexed Drawings.
Ninthly. The employment of the combined cupola and reverberatory
furnace, constructed as shown at Figures 1 and 2 on Sheet D., and
working under pressure of confined gaseous matters, for the purposes and
in the manner described.
Tenthly. The employment of cupola furnaces constructed as shewn at
Figure 3, Sheet D., such furnaces working under pressure of confined
gaseous matters, for the purposes and in the manner described.
Eleventhly. The mode herein described of constructing mercurial
gauges to indicate the pressure of gaseous matters in furnaces employed
for the purposes described.
Twelfthly. The constructing the peep holes of high-pressure furnaces
in the manner described.
Thirteenthly. The enclosing the orifices by which the products of com-
bustion escape from furnaces used in the manufacture of malleable iron
and steel, and working under high pressure in suitable tubes or passages
to lessen the noise produced by their escape.
Fourteenthly. The forming the escape apertures of high-pressure
furnaces used in the manufacture of malleable iron and steel in metal,
having water passages formed therein to prevent their rapid destruction
by heat.
In witness whereof, I, the said Henry Bessemer, have hereunto set
my hand and seal, this Tenth day of November, in the year of our
Lord One thousand eight hundred and sixty-nine.
HENRY BESSEMER. (L.S.)