Year: 1855

page_text: Sealed the 18th December 1855, and dated the 18th June 1855.

page_text: vertical position, or as nearly so as will admit of the descent of the said pieces
of iron and charcoal through them by the force of gravity whenever the lower
portion of the vertical column of materials is removed. The upper and lower
parts of the said retorts, tubes, or chambers are to be kept cool, by placing
them in a tank of water or by exposing their outer surfaces to the atmosphere,
while the central portion is exposed to a red heat in a suitable furnace or
oven. The parts exposed to the action of the fire, I prefer to construct of fire-
clay, while the top and bottom ends of the retorts, tubes, or chambers may be
made of iron, to facilitate the cooling of them. The lower ends of the said
retorts,, tubes, or chambers should be provided with sliders or stop pieces
below the tubes, for the discharge of a portion of the materials from time to
time. When a portion of the charge of materials is thus allowed to escape from
the lower ends of the retorts, tubes, or chambers, a fresh portion should be
admitted into the upper end of them, and thus the process rendered continuous
after the process of cementation. The charcoal may be separated from the
converted iron by allowing the mixed materials to fall into water, from the
surface of which the charcoal may be removed, or the separation may be
otherwise accomplished. In some cases, however, I dispense with the process
of conversion by cementation, and in lieu thereof I do not carry the process
of puddling iron so far as to entirely deprive it of its carbon; but I stop the
process of puddling at that point when the workmen judge from its appearance
that it contains fully as much carbon as is contained in ordinary steel. Such
puddled iron may be used alone or mixed in any proportion with steel that
has been converted by the process of cementation; in either case the smelting
of the metal so treated is to be effected in close pots or vessels, from which the
atmosphere and vapours of the furnace are excluded during the melting
process. When puddled, scrap, or other iron has been converted into steel by
cementation in upright retorts, as herein-before described, or by any other
convenient means, or when iron is partially deprived of its carbon by puddling,
or when iron bars are converted into blister steel by cementation, I proceed to
melt the same in order that the crude steel so produced may be cast-into- ingots
for the purpose of being rolled or tilted into sheets, bars, or rods, or in order
that the molten steel may be run into moulds for the production of various
articles in cast steel by the process of founding; for which purpose I con-
struct a furnace divided into a number of compartments or chambers, each one
having a separate fire-grate and flue, so that each compartment may be worked
independently of the other. This furnace is, by preference, of a circular form,
having a large cone rising from its centre, around which the separate compart-
ments are arranged; the mouth of each one is on a level or nearly so with the

page_text: floor of the foundry, and below ground is a large "cave," into which the ash-
pits of the several fire-grates open, and by means of which the workmen get
access to the under side of the fire-grates; the cave also serves as a means of
supplying air to the furnace, the air descending through gratings in the
foundry floor. The central cone is so constructed that separate flues for each
compartment of the furnace are formed in the thickness of its walls; the
central part is open at the top to the air, and the space within the cone at
its base forms, the casting pit, in which the moulds are placed; accèss is had.
to the casting pit through an arched opening on one side of the cone. Into
each compartment of the furnace I place a fire-clay or black lead melting
pot or vessel, which should be raised above the fire-bars on a hollow fire-clay
support; the pots or vessels are to have a tapping hole in the lower part of
them, which may be stopped up with damp sand, loam, or luting, access to
which may be had through the hollow support of the pot from the under side
of the fire-bars when the tapping hole is placed vertically, but when placed
in a horizontal direction the tapping hole may be opened by introducing a
rod through a hole made in the front of the furnace for that purpose. I,
however, prefer that the hole in the pot should have one end of a long fire-
clay plug inserted in it, the top end of the plug rising thro' the metal to the
top of the pot, which plug may be taken hold of by a pair of tongs and lifted.
up when the metal is to be discharged; the joint formed by the conical end
of the plug and the conical tapping hole may be kept tight by a little bottle,
glass, or luting, which may be renewed after each emptying of the pot. The
upper part of the pot I form of a dome or hemispherical form, having a
central hole for the plug to pass through, and one or more feeding holes with
suitable plugs to close them air-tight; in some cases it may be found con-
venient to stop the tap hole with an iron plug from below, the end of
which is protected by some loam, luting, or other similar matters. The different
chambers may be of a segmental form, but I prefer to make their interior of a
barrel form, and to have a revolving circular cover with a small excentric
feed hole for the supply of fuel, and a central hole to allow access to the pot..
The cover should be mounted on wheels, and have a rim or flange fitting so
close to the top of the furnace as to exclude the air as far as possible, or a sand
joint may be formed. At the back of the ash-pit of each compartment there
is an opening in the wall of the conc, through which at the time of casting I
place an iron gutter lined with loam, one end of each gutter being placed
below the tap hole of one of the melting pots, while the other end of the gutters
communicate with the gate of the mould, so that on a signal being given the
workmen simultaneously open the tapping holes of all the melting pots, the

page_text: --
contents of which may thus be rapidly accumulated in a single casting when
required; but when small castings are required, the tap hole should be stopped
with a long fire-clay plug, as before described, which may be used as a. valve
to let out as much metal as is required at a time; the plug keeping the tap hole
shut until another mould is ready. In order to obtain the intense heat requisite
to melt steel, I place good hard coke all around the melting pot, and also
cover over the top of it, so that the pot may be completely enveloped in the
burning fuel. When a mixture of iron with the steel is to be made, I put the
iron at the top of the charge of steel, so that when it melts it will run down
and fill the interstices between the pieces of steel and assist in their fusion, or
the iron may be melted in another furnace, and poured in a fluid state into the
melting pot among the pieces of highly heated steel. Although I have herein
described a furnace consisting of several compartments with melting' vessels in
each of them, and which is particularly adapted for the production of heavy
castings, I nevertheless wish it to be understood that in carrying out the
melting of steel or a mixture of steel and iron on a small scale, a single pot and
chamber may be used in lieu of the combination of pots and chambers before
described, such pot being set in the furnace and provided with a tapping hole
for the discharge of the metal.
In order that my said Invention may be carried out with economy in those
situations where coke is more expensive than coal as a fuel for melting, I make
such alterations in the form of the melting vessels and furnace as will admit of
the use of coal in its raw state; the vessels or retorts used in this case being
also made with closed tops to exclude the atmosphere and gases of the furnace,
and are in like manner provided with tapping holes for the discharge of the
fluid metal from them..
In order to carry out this part of my said Invention, I construct a furnace
similar in form to the reverberatory furnaces in common use for puddling iron,
the part behind the fire bridge being occupied with fire-clay vessels or retorts,
-which-should-be-placed-crosswise of the furnace,-and-be supported-at-different
parts, so as to form a series of flues beneath them, while the flame is also allowed
to pass over and envelope them as much as possible. The vessels or retorts should
be made with closed ends and tops, with the exception of a feeding or charging
hole. near the upper part, and a small tapping hole at the bottom part, which is
to be plugged with loam, damp sand, or a plug of fire-clay during the melting
of the materials, after which the tapping holes are opened, and the contents of
the melting vessels may be run into a ladle or direct into the mould; or the
after part of the furnace may be so formed as to melt down the iron, or to
receive a charge of melted iron from another furnace; and the steel may in that

page_text: case be melted alone, and be afterwards tapped out and allowed to flow into
the fluid iron in the after part of the furnace, from which the whole may be
run into moulds, whereby cast steel articles may be produced, or articles
composed of a mixture of steel and iron.
.
by the said Henry Bessemer in the Great Seal Patent Office on the
18th December 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Queen Street Place, New Cannon Street, in the City of London,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of June, in the year of our Lord One
thousand eight hundred and fifty-five, in the eighteenth 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, administrators, 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 CAST STEEL, AND MIXTURES OF STEEL AND CAST IRON," upon the
condition (amongst others) that I, the said Henry Bessemer, by an instrument
in writing under my hand and seal, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to be
performed, 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 consist, firstly, in preparing the iron for its conversion
into steel; for which purpose I put bar, plate, hoop, or scrap. iron between a
pair of slitting rolls," whereby they are cut into narrow strips, which are
afterwards put crosswise through the same rolls, so as to cut the metal into

page_text: small pieces; or instead of this last operation a revolving cutter or other suitable
shearing machinè may be used; but pieces of scrap iron, such as are punched
out for rivit holes, malleable iron turnings, and other pieces sufficiently small,
to be conveniently put through the converting retorts, herein-after described,
will not require this process of cutting up. In some cases I use granulated
puddled iron in lieu of the small pieces of bar, plate, hoop, or scrap iron. The
metal so granulated or cut will then be in a condition suitable for its conversion
into steel by the process of cementation with charcoal or other carbonaceons
substances in close retorts, tubes, or chambers placed in a vertical position, or
as nearly so as will admit of the descent of the said picces of iron and charcoal
through them by the force of gravity whenever the lower portion of the vertical
column of materials is removed. The upper and lower parts of the said retorts,
tubes, or chambers are to be kept cool, by placing them in a tank of water, or
by exposing their outer surfaces to the atmosphere, while the central portion is
exposed to a red heat in a suitable furnace or oven. The parts exposed to the
action of the fire I prefer to construct of fire-clay, while the top and bottom
ends of the retorts, tubes, or chambers may be made of iron to facilitate the
cooling of them. The lower ends of the said retorts, tubes, or chambers should
be provided with sliders or stop pieces below the tubes for the discharge of a
portion of the materials from time to time. When a portion of the charge of
materials is thus allowed to escape from the lower end of the retoris, tubes, or
chambers, a fresh portion should be admitted into the upper end of them, and
thus the process rendered continuous after the process of cementation. The
charcoal may be separated from the converted iron by allowing the mixed
materials to fall into water, from the surface of which the charcoal may be
removed, or the separation may be otherwise accomplished.
On Sheet A of the annexed Drawings I have represented an apparatus for
the conversion into steel of the small pieces of iron herein-before referred to;
on which Sheet Figure 1 is a vertical cross section on the line A, B, of
Figure 4 Figure 2-is-a-longitudinal-section-on-the-line C, D, of Figure4;
Figure 3 is a side elevation; Figure 4 is a horizontal section on the line E, F,
of Figure 2; Figure 5 is a horizontal section on the crooked line G, H, of
Figure 1; and Figure 6 is an end elevation of the same.
a, a, a, are fire-clay retorts or tubes, placed in a vertical position, the lower
ends of which are inserted in flange ring formed on the upper side of the
cast-iron tanks b. On the inside of these tanks there are tubes of iron c, c, c,
of the same internal diameter as the interior of the retorts a, with which they
communicate. The lower end of the tubes c pass out through the bottom of
the tank band are left open. The upper end of the fire-clay retorts a pass up

page_text: through the arched roof of the oven d, and are bolted to the iron feeding tubes
e, e, the upper ends of which are secured to the iron stage f, surrounded by a
railing, on which the materials to be used in the process are laid, and on which
the workmen who fill the tubes are stationed. g, g, are fire-grates, one at each
end, having feeding doors h, and ash-pits i, i; above the fire-grates there is
formed an arch of fire-brick i, j, having square holes formed therein for the
escape of heated matters into the large chamber or oven d. k, k, are hori-
zontal passages leading from the fire-grates to the outer walls of the oven;
these passages have outlets *, by means of which the heated matters are
conducted to and pass up between the outer wall and retorts, and thus tend
to distribute and equalize the temperature. m, m, are small plugs of fire-clay,
by removing which access may be had to the flues h, k, for the purpose of
clearing them; the products of combustion escape into the chimneys n, n,
through the openings r, r. The upper part of the chimneys are shewn broken
off; they should rise about twenty feet above the oven, and be provided at top
with damper plates, so that the workmen may with facility regulate the tem-
perature of the oven; the operation of which is as follows:-The small pieces
of scrap or puddled iron to be cemented are mixed with granulated charcoal
or otlier suitable carbonaceous matter, and hoisted in any convenient way on to
the stage f, and are then to be shovelled into the feeding tubes; the materials
will fall down as far as the stop pieces s, s, and gradually accumulate above
them until the tubes c, c, c, and the retorts a, a, a, and feeding tubes e, e, e, are
all filled to the top; the fires having gradually been got up, must be main-
tained steadily until the materials within the retorts a, a, a, have become heated
to a bright red heat; the workmen will then proceed to rake off a portion of
the materials from the supports s, s, which will slide down to the mouth of the
arched opening t, from which they are to be removed. These first portions in
commencing work with a new oven must be again put into the feeding
tubes, which are in all cases to be kept filled; after a few hours a portion
more of the materials are to be removed from the stop pieces s, in doing
which the whole column of materials will be lowered, the red-hot portions which
occupy the retorts a will be lowered down into the cooling tubes c, c, c, which
are surrounded by water, and by which the heat of the materials will be
absorbed previous to their discharge from the space left between the lower
ends of the tubes c and stop s. Whenever any portion of the cemented steel is
thus withdrawn, the workmen on the stage will immediately fill up the space
left in the tubes e, e, e, by the sinking down of the material, and thus exclude
the atmosphere from that portion of them which occupy the red-hot retorts, so
that the operation of the apparatus may go on continuously.

page_text: The time during which the pieces of iron mixed with charcoal are exposed
to the cementing process in the retorts being regulated by the quantity removed
each time from the lower end of the tubes, and the interval allowed to take
place between the times of discharge, by an examination of the fracture of
the pieces of steel, it will at once be seen how far the process of conversion
has been carried, and thus afford the necessary guide for the workmen to regulate
the time of the passage of the materials through the retorts. In some cases,
however, I dispense with the process of conversion by cementation, and in lieu
thereof I do not carry the process of puddling iron so far as to entirely deprive
it of its carbon, but I stop the process of puddling at that point when the
workmen judge from its appearance that it contains fully as much carbon as is
contained in ordinary steel; such puddled iron may be used alone or mixed in
any proportion with steel that has been converted by the process of cementa-
tion; in either case the smelting of the metal so treated is to be effected in close
- pots or vessels, from which the atmosphere and vapours of the furnace are
excluded during the melting process. When puddled, scrap, or other iron has
been converted into steel by cementation in upright retorts, as herein-before
described, or by any other convenient means, or when iron is partially
deprived of its carbon by puddling, or when iron bars are converted into
blister steel by cementation, I proceed to melt the sand, in order that
the crude steel so produced may be cast into ingots for the purpose of
being rolled or tilted into sheets, bars, or rods, or in order that the molten
steel may be run into moulds for the production of various articles in cast
steel by the process of founding, for which purpose I construct a furnace
divided into a number of compartments or chambers, each one having a
separate fire-grate and flue, so that each compartment may be worked inde-
pendently of the other. This furnace is of (by preference) a circular form,
having a large cone rising from its centre, around which the separate com-
partments are arranged. The mouth of each one is on a level or nearly so with
the floor of the foundry, and below ground is a large "cave," into which the
ash-pits of the several fire-grates open, and by means of which the workmen
get access to the under side of the fire-grates; the cave also serves as a means
of supplying air to the furnace, the air descending through gratings.in the
foundry floor; the central cone is so constructed that separate flues for each
compartment of the furnace are formed in the thickness of its walls; the
central part is open at the top to the air, and the space within the cone at its
base forms the casting pit in which the moulds are placed; access is had to the
casting pit through an arched opening on one side of the cone. Into each
compartment of the furnace I place a fire-clay or black lead melting pot or

page_text: vessel, which should be raised above the fire-bars on a hollow fire-clay support;
the pots or vessels are to have a tapping hole in the lower part of them,
which may be stopped up with damp sand, loam, or luting, access to which
may be had through the hollow support of the pot from the under side of the
fire-bars when the tapping hole is placed vertically, but when placed in a
horizontal direction the tapping hole may be opened by introducing a rod
through a hole made in the front of the furnace for that purpose. I, however,
prefer that the hole in the pot should have one end of a long fire-clay plug
inserted in it, the top end of the plug rising through the metal to the top
of the pot, which plug may be taken hold of by a pair of tongs, and lifted up
when the metal is to be discharged; the joint formed by the conical end of the
plug and the conical tapping hole may be kept tight by a little bottle glass,
or luting, which may be renewed after each emptying of the pot. The upper
part of the pot I form of a dome or hemispherical form, having a central
hole for the plug to pass through, and one or more feeding holes with suitable
plugs to close them air-tight; in some cases it may be found convenient to
stop the tap hole with an iron plug from below, the end of which is protected
The different chambers may
by some loam, luting, or other similar matters.
be of a segmental form, but I prefer to make their interior of a barrel form,
and to have a revolving circular cover with a small excentric feed hole for the
supply of fuel, and a central hole to allow access to the pot. The cover should
be mounted on wheels, and have a rim or flange fitting so close to the top of
the furnace as to exclude the air as far as possible; or a sand joint may be
formed. At the back of the ash-pit of each compartment there is an opening
in the wall of the cone, through which at the time of the casting I place an
iron gutter lined with loam, one. end of each gutter being placed below the tap
hole. of one of the melting pots, while the other end of the gutters communi-
cate with the gate of the mould, so that on a signal being given, the workmen
simultaneously open the tapping holes of all the melting pots, the contents of
which may thus be rapidly accumulated in a single casting when required;
but when small castings are required, the tap hole should be stopped with a
long fire-clay plug, as before described, which may be used as a valve to let
out as much metal as is required at a time, the plug keeping the tap hole shut
until another mould is ready.
In order to obtain the intense heat requisite to melt steel, I place good hard.
coke all around the melting pot, and also cover over the top of it, so that the
pot may be completely enveloped in the burning fuel. When a mixture of iron
with the steel is to be made, I put the iron at the top of the charge of steel,
--so that when it melts it will run down and fill the interstices between the

page_text: pieces of steel and assist in their fusion; or the iron may be melted in another
furnace, and poured in a fluid state into the melting pot among the pieces of
highly heated steel. Although I have herein described a furnace consisting of
several compartments with melting vessels in each of them, and which is
particularly adapted for the production of heavy castings, I nevertheless. wish
it to, be understood that in carrying out the melting of steel or a mixture of
steel and iron on a small scale, a single pot and chamber may be used, in lieu
of the combination of pots and chambers before described, such pot being
set in the furnace and provided with a tapping hole for the discharge of the
metal.
The mode of arranging the various parts of my improved furnace for melt-
ing steel, and the way in which the contents of several melting pois are run
into one casting, is shown on Sheet B of the annexed Drawings; where
Figure I is a vertical section, taken through the centre thereof; Figure 2 is a
horizontal section, taken on the crooked line A, B, of Figure 1; and Figure 3
is a vertical section of the melting vessel and one compartament of the fur-
nace, on a larger scale: Figure 4 is a plan of the revolving cover of the same;
and Figure 5 is a plan of the fire-grate. a, a, are the walls of the large cone;
in which the separate chimneys bare formed; c, c, are the barrel-shaped
chambers or compartments in which the melting pots or crucibles are placed
on a fire-clay support d; e, e, are the ash-pits, and the circular cave to which
access may be had by steps, not shewn in the Drawings. The central cone
rises above the roof g of the foundry, and has a covered top, formed of iron,
so arranged as to give egress to the vapours from the flues b, and also allow
the escape of hot air from the central part of the cone, the lower part of
which forms the casting pit in which the moulds are placed. h, h, are openings
in the wall of the cone, through which the iron gutters i, i, pass. These gutters
are covered, or are formed tubular at that end which comes beneath .the
melting pot, while the other portion is left open.
or sand, and are placed in a position inclining
the-mould, so as to cause a rapid flow of the metal in that direction. m is a
vessel of iron, lined with loam, over the exterior edge of which the lower ends of
the gutters project. In its centre there is a hole, which is stopped up at the time
of commencing to found with a plug of iron coated with loam. Beneath the
vessel m is placed the mould in which the object desired is to be cast. For
the purpose of illustration, I have shewn at n in the Drawing a section of a
cannon moulded in loam, enclosed in an iron case or flask, and retained in an
erect position by struts o. When using this furnace for casting large objects,
such as the gun represented, each separate compartment is heated by a fire
The gutters are lined with loam
downwards towards the gate of

page_text: being made therein; the melting pots are heated to a bright red heat in a suit-
able oven or pot arch, in a manner well understood, and are then transferred
to the separate compartments before named. It will be observed, by reference
to Figure 3, that the pots are formed with a conical hole in the bottom of
them; into this hole the end of the plug r is placed. This plug extends
upwards, through the top of the pot, and has a square end for the facility
of holding it when required by a pair of tongs. In the top of the pot there
is also an opening, secured by a fire-clay stopper s, for the purpose of charging
the pots with metal. As soon as the pots are placed upon the fire-clay
support d, and the plug rods r put into their places, the stoppers s are
removed, and a small quantity of broken bottle glass, slag, or other vitreous
matter should be thrown into the pot, which on melting will run down and
keep good the joint formed by the plug rod r; after this, the steel or a mix-
ture of steel and iron in any desired proportion may be put in at the opening
in the top of the pot, and the plugs replaced; the fires of the separate com-
partments must then be urged, until the contents of the several pots arė
melted. The mould, having been secured in place, a plug is put into the
central hole of the vessel m, which forms the gate of the mould. On a signal
from the founder, the plug rods of the separate pots are to be lifted simul-
taneously, when a rapid flow of molten steel will take place and accumulate in
the vessel m; the founder will then raise the plug, by which the luting round
the top of it will be loosened, and admit air into the pot, and allow the metal
to flow into the mould, and thus cast or found the gun or other article. The
plug, rods are then to be lowered again into their seats and preparations
made, for repeating the process. By reference to Figures 3 and 4, it will be
seen that there is an opening u, having a stepper v fitted to it, for the purpose of
supplying fuel to the furnace; and in order that this aperture might supply all
parts of the furnace with facility, and allow a poker to be introduced to push
down the fuel, I mount the cover of the furnace on wheels x, which run
upon a circular rail y, formed on the top iron plate of the furnace. In the
centre of this cover is another aperture with a stopper z, which is for the
purpose of admitting a pair of tongs to lift up the plug rod r at the time of
discharging the metal, at Figure 5, which shews a plan of the fire-grate. It
will be seen that four fire-bars are cast in one piece, having a hole p for the
purpose of allowing the melted steel to flow uninterruptedly into the gutters.
In order that my said Invention may be carried out with economy in those
situations where coke is more expensive than coal as a fuel for melting, I make
such alterations in the form of the melting vessels and furnace as will admit of
the use of coal-in its raw-state, the vessels or retorts used in this case being

page_text: also made with closed tops to exclude the atmosphere and gases of the furnace,
and are in like manner provided..with tapping holes for the discharge of the
fluid metal from them.
H....
. In order to carry out this part of my said Invention, I construct a furnace
.similar in form to the reverberatory furnaces in common use for puddling iron
the part behind the fire bridge being occupied with fire-clay vessels or retorts,
which. should be placed crosswise of the furnace, and be supported at different
parts, so as to form a series of flues beneath them, while the flame is also
allowed to pass over and envelope them as much as possible. The vessels or
retorts should be made, with closed ends and tops, with the exception of a
feeding or charging hole near the upper part, and a small tapping hole at the
bottom part, which is to be plugged with loam, damp sand, or a plug of fire-
clay during the melting of the materials; after which the tapping holes are
opened, and the contents of the melting vessels may be run into a ladle or
direct into the mould; or the after part of the furnace may be so formed as to
melt down the iron, or to receive a charge of melted iron from another furnace;
and the steel may in that case be melted alone and be afterwards tapped out
and allowed to flow into the fluid iron in the after part of the furnace, from
which the whole may be run into moulds, whereby the cast steel articles may
be produced, or articles composed of a mixture of steel and iron.
In order that this mode of melting with (raw coal) steel, or mixtures of
steel and cast or pig iron, may be fully understood, I have shewn on Sheet C
of the annexed Drawings a longitudinal section of the furnace I use for that
purpose at Figure 1. Figure 2 is a cross section on the line A, B, of Figure 3;
and Figure 3 is a horizontal section on the line C, D, of Figure 1.
a is the
fire-grate, with an arched roof above it, similar to the usual construction of
reverberatory furnaces; b, b, are fire-clay retorts, supported at their ends on a
projection cof outer walls c, and also by two small walls d, d, which form
between them the flues e, e, c, leading beneath the retorts; f, is the roof or
arch over the retorts, beneath which the flame'is conducted to the chimney g
after having passed along the flues e, e. The retorts are placed so near together
as to leave only a very small passage for the flame between them. h, h, are
openings in the side of the furnace, by which access may be had to the mouth
of the retorts. This mouth-piece is. closed. with a stopper, which may be
removed at the time of putting in the metal. . On the opposite side of the furnace
there are openings i, i; through which the stoppers may be removed from the
lower part of the retorts at the time of discharging the molten metal there-
from. These apertures may be plugged with moist sand or loam, as is practised
in cupola furnaces used for melting iron. m is a projecting lip, which may be

page_text: covered with loam, and to which a gutter may be joined to lead off the fluid
metal to the mould.
Having now described, my Invention, and the manner in which the same is
to be carried into effect, I desire it to be understood that I do not confine
myself to the precise details herein specified, so long as the peculiar character
of my said Invention is retained; but what I do claim is,-
First, the conversion of iron into steel in retorts, tubes, or chambers placed
in a vertical position, or as nearly so as will allow the iron or steel under
operation to descend through them by the force of gravity, and thus allow the
process of cementation to go on continuously.
Secondly. I claim the melting in close pots or vessels (either alone or mixed
with steel that has been otherwise manufactured) steel made by puddling, pig.
or refined iron until so much carbon only is left in combination with it as to
constitute steel.
Thirdly, I claim the arrangement of separate compartments or pot chambers
in a furnace for founding steel or mixtures of steel and cast iron, and the mode
of conveying the molten metal to the mould, as described.
Fourthly, I claim the discharge of fluid steel, or a mixture of steel and cast.
iron, from a hole in the lower part of the pot or vessel in which it is melted,
and the closing of such hole by a plug or valve of fire-clay, or a stopping of
loam or lute of any suitable kind.
Fifthly, I claim mounting the cover of the furnace on wheels, and the use
of the excentric feeding hole, as described.
Lastly, I claim melting steel, or mixtures of Steel or cast iron, in retorts, as
described.
In witness whereof, I. the said Henry Bessemer, have hereunto set my
hand and seal, this Seventeenth day of December, in the year of our
Lord One thousand eight hundred and fifty-five.
Witness,
T. D. BRANGWIN.
HENRY BESSEMER. (L.S.)