IMPROVE- MENTS IN THE MANUFACTURE OF IRON AND STEEL
Year: 1856

page_text: LETTERS PATENT to Henry Bessemer, of Queen Street Place, New
Cannon Street, in the City of London, for the Invention of "IMPROVE-
MENTS IN THE MANUFACTURE OF IRON AND STEEL."
Sealed the 25th November 1856, and dated the 19th August 1856.
PROVISIONAL SPECIFICATION left by the said Henry Bessemer at the
Office of the Commissioners of Patents, with his Petition, on tho
19th August 1856.
I, HENRY BESSEMER, of Queen Street Place, New Cannon Street, in the
City of London, do hereby declare the nature of the Invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF IRON AND STEEL," to be as follows:-
The process of puddling iron in Great Britain is generally carried on in
furnaces which reverberate the flame and gaseous matters evolved by the
combustion of mineral coal on to the fluid or semi-fluid metal, whereby the
iron is found to be more or less injured by the gaseous matters thus brought
in contact with it, while the consumption of coal adds greatly to the cost of
the process.
Now, the object of my present Invention is to render the crude molten iron
obtained from the smelting furnace, or to render remelted pig or refined iron,
malleable in part by the process of puddling, or by a process producing a
similar effect, and in part by forcing into and among the particles of such fluid
iron, jets or currents of air, or of some other gaseous matter containing or

page_text: capable of evolving sufficient oxygen to raise the temperature of the metal so
far as to admit of the puddling or other analogous process being carried on
without the use of any fuel or heat other than is obtained by the introduction
of oxygen into the metal.
In carrying my Invention into practical operation, I prefer to use an iron
vessel or chamber lined with fire bricks or other suitable refractory substances,
and to close over such vessel or chamber so as to prevent as far as possible the
loss of heat; there must, however, be left one or more apertures for the escape
of the gaseous matters conducted into or evolved by the metal during the
process. Into the lower part of the vessel I insert one or more tuyeres or jet
pipes made of fire clay or other suitable refractory substance, or they may be
made of iron, and be protected by the passage of water through them, as
already practised in making tuyeres. Through these tuyeres I force the
aforesaid gaseous matters, alone or in combination with any solid substances
capable of evolving oxygen, such substances, being first reduced to powder, may
be carried by the currents of gaseous matter into the fluid metal; I also put
into the vessel or chamber some of the fused oxide of iron or scoria, formed
during the preceding operation in the same vessel, which will assist in the
decarbonization of the crude metal; hydrogen gas, or any matter capable of
evolving hydrogen may also be used, either alone or in combination with other
gaseous matter containing oxygen, for the purpose of combining with the
sulphur contained in the crude metal, or for the purpose of adding to its
temperature. By these means the fluid crude iron may be decarbonized and
rendered malleable, or the process may be discontinued at an earlier stage of
the process, and before the malleable condition is obtained; in either case, I
prefer to pour or run the charge of metal so treated into another chamber or
vessel constructed of iron, and lined with fire brick or other suitable material
not easily acted upon by the metal or scoria. This chamber or vessel may be
heated, previous to the commencement of the process, by passing the waste heat
of the converting vessel into or through it, or such waste heat may be applied
throughout the puddling or other analogous process in this last named vessel
or chamber; the metal may be stirred or raked about until it passes from the
fluid to the pasty or solid condition, and is broken or divided into small
fragments, the fluid scoria obtained in the first operation diffusing itself
throughout the mass, and thereby assisting in the decarbonization of the metal,
and in rendering the disjointed mass suitable for the after processes to which
it is subjected. The workman well fashion the mass into one or more pieces
with an implement such as is used in the ordinary process of puddling, and
remove the same from the puddling vessel or chamber, to be squeezed or

page_text: otherwise treated as commonly practised in the manufacture of iron; or in lieu
of the raking and stirring process, the chamber or vessel may be so constructed
as to rotate on an axis or to move to and fro, so that by such movement of the
vessel the metal will be prevented from becoming solidified in a single mass,
but will become broken up into fragments and mixed with the scoria, and
thus resemble an ordinary puddle ball, but of much larger dimensions; or the
mass so agitated may be turned out of the vessel into a mould or die, in which
it may be subjected to powerful pressure or repeated heavy blows by any
suitable apparatus, and while still in a highly heated state may be rolled into
bars, plates, or rods; or in lieu of this stirring or agitation of the metal,
it may continue to have steam or other gaseous matters forced into it in
quantities not sufficient to keep up the fluid condition of the metal, so that a
spongy or granular mass will be produced, and which may be treated in a
similar manner to an ordinary puddle ball by squeezing and rolling.
In the process of making malleable iron and steel by the forcing of oxygen
into the fluid metal, I have found that the heat evolved may be advantageously
applied to the remelting of pig iron by allowing such waste heat to enter a
reverberatory arch or chamber, built in immediate connection with the
couverting vessel, in which arch the pigs of iron may be so placed as to bo
exposed to the full action of the heated matters which escape from the
converting vessel. The iron, so melted, may be afterwards rendered malleable
by running it into the converting vessel, and there forcing into it currents of
gaseous oxygen, as before described, so that the waste heat of one converting
operation may be made available for the remelting of the crude iron required
for the next, or the waste heat may be applied to a suitably constructed boiler,
for the purpose of generating steam to be used for the production of motive
power, or for other purposes in the manufacture of iron and steel. I have
found that the slag or scoria which is thrown out of vessels used for the
conversion of crude iron into malleable iron or steel, by forcing air or other
gaseous matters into the fluid metal, contains a great many small grains of
metallic iron, and that such slags also contain a large quantity of oxide of iron,
which it is desirable to recover or convert into metallic iron. For this purposo
I either construct a chamber in immediate connection with the converting
vessel, so that such slags may be thrown therein, or I construct such chamber
beyond and in connection with the remelting arch herein-before described. In
either case, the slag which is thrown therein in a heated state is to be mixed
with anthracite coal, or other carbonaceous matter, in sufficient quantity to
reduce the oxide and form metallic iron. The carbonaceous matters used for
this purpose should be thrust below the fluid scoria, in order as far as possible

page_text: to prevent combustion; the reduced metal in the state of crude iron may be
tapped out at the lower part of the chamber from time to time, and the slag,
after the metal has been obtained therefrom, may be run off at a higher level;
or in lieu of introducing solid carbonaceous matters into the fluid scoria, coal
gas or any other carbonaceous fluid or gaseous matter may be forced through
suitable tuyeres into the fluid scoria, and the metallic iron be thereby separated
from the slag. I have also found that the grains or lumps of metallic iron may
be readily separated by crushing the spongy slags when cold, and sifting. or
winnowing the crushed matter, or by the use of magnets. .I have also found
the rich oxydized slags, produced in the converting vessel; useful in preventing
the injurious effects of mineral fuel in the furnaces employed in reheating or
retaining the heat of ingots or masses of metallic iron and steel that have been
made from crude iron by forcing currents of air or other gaseous matters.
therein, are generally more or less spongy or cellular on their external surfaces,
I therefore throw on to such ingots or masses of iron and steel, when in the
reheating furnace, some broken slags, so that they may fuse and run or spread
over the surface of the ingots; or I form a shallow bath on the bed of the
reheating furnace, in which the ingots may be placed, and be turned over, so as
to become coated with the fluid slag contained therein, and be thus defended
from the action of the vapours of the furnace. It will also be found that the
cavities on the surface of the ingots or masses will, in consequence of the
presence of the fluid scoria, be easier welded or closed up, and the bar of iron
or steel thereby improved. In this way borax, glass, or other saline or vitreous
matters may be used to defend the surface of the ingots or masses of iron and
steel, and assist in the closing up of any fissures or cavities that originally
existed in them, or which may be made during the hammering or rolling of
such ingots or masses of metal.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Bessemer in the Great Seal Patent Office on the
19th February 1857.
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 Nineteenth day of August, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her reign,

page_text: 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 IRON AND STEEL," 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, 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 per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
The process of puddling iron in Great Britain is generally carried on
in furnaces which reverberate the flame and gaseous matters evolved by the
combustion of mineral coal on to the fluid or semi-fluid metal, whereby
the iron is found to be more or less injured by the 'gaseous matters thus
brought in contact with it, while the consumption of coal adds greatly to the
cost of the process.
Now, the object of my present Invention is to render the crude molten iron
obtained from the smelting furnace, or to render remelted pig or refined iron,
malleable in part by the process of puddling, or by a process producing a
similar effect, and in part by forcing into and among the particles of such fluid
iron, jets or currents of air, or of some other gaseous matter containing
or capable of evolving sufficient oxygen to raise the temperature of the metal
so far as to admit of the puddling or other analagous process being carried on
without the use of any fuel or heat other than is obtained by the introduction
of oxygen into the metal, or by the introduction of hydrogen therein, in the
manner herein-after more particularly described.
In carrying my Invention into practical operation I prefer to use an iron
vessel or chamber lined with fire bricks or other suitable refractory substances,
and to close over such vessel or chamber so as to prevent as far as possible the
loss of heat; there must, however, be left one or more apertures for the escape

page_text: of gaseous matters conducted into or evolved by the metal during the process.
Into the lower part of the vessel I insert one or more tuyeres or jet pipės,
nade of fire clay or other suitable refractory substance, or they may be made
of iron, and be protected by the passage of water through them, as already prac-
tised in making tuyeres. Through these tuyeres I force the aforesaid gaseous
matters alone, or in combination with any solid substances capable of evolving
oxygen; such substances, being first reduced to powder, may be carried by the
currents of gaseous matter into the fluid metal. I also put into the vessel or
chamber some of the fused oxide of iron or scoria formed during the pre-
ceeding operation in the same vessel, which will assist in the decarbonization
of the crude metal; bydrogen gas, or any matter capable of evolving hydrogen,
may also be used, either alone or in combination with other gaseous matter
containing oxygen, for the purpose of combining with the sulphur contained
in the crude metal, or for the purpose of adding to its temperature.
By these means the fluid crude iron may be decarbonized and rendered
malleable, or the process may be discontinued at an earlier stage of the process,
and before the malleable condition is obtained; in either case, I prefer to pour
or run the charge of metal so treated into another chamber or vessel con-
structed of iron, and lined with fire brick or other suitable material not easily
acted upon by the metal or scoria; this chamber or vessel may be heated
previous to the commencement of the process by passing the waste heat of the
converting vessel into or through it, or such waste heat may be applied throughout
the puddling or other analagous process; in this last-named vessel or chamber
the metal may be stirred or raked about until it passes from the fluid to
the pasty or solid condition, and is broken or divided into small fragments, the
fluid scoria obtained in the first operation diffusing itself throughout the mass,
and thereby assisting in the decarbonization of the metal, and in rendering the
disjointed mass suitable for the after processes to which it is subjected.
In order that the apparatus which I prefer to employ in carrying this part
of my said Invention into practical operation may be fully understood, I have
on the annexed Sheet of Drawings shewn a vertical section thereof at
Figure 1, taken on the line A, B, of Figure 2, which is a horizontal section of
the same, taken on the line C, D, of Figure 1. a is the exterior shell of the
apparatus, which is constructed of iron plates, and is lined with fire bricks b; it
is divided into two chambers c and d by a partition wall *; the upper part of
the double chamber is arched over in such a manner as to leave a space at e,
by means of which a communication is formed between the two chambers.
Into the lower part of the chamber c are inserted fire clay or other tuyere
pipes f, each of which have fitted to them the conical end of the branch pipes

page_text: g; these pipes descend at 9* below the floor level, and are there joined
to a main blast pipe through which atmospheric air, or any gaseous matter
containing or capable of evolving oxygen or hydrogen, may be forced into the
fluid metal occupying the lower part of the chamber c, and be made to bubble
up and ascend through and among the particles of such fluid metal, after the
manner described in a former Patent granted to me, and bearing date the
Twelfth of February One thousand eight hundred and fifty-six. When atmo-
spheric air is thus forced into the fluid metal the carbon, silicon, and some
other impurities will be rapidly driven off, and the temperature of the metal will
be greatly raised; should the crude iron subjected to this process be known
to contain sulphur, it will be found advantageous to pass hydrogen gas from
time to time through the tuyeres into the metal, in order that the same
may combine with the sulphur and carry it off; this application of hydrogen
gas may precede the decarbonization of the crude iron by oxygen in the
chamber c, because the metal will in its crude or carbonized state be less
liable to solidify by the abstraction of a portion of its heat by the passage of
gas through it. The use of hydrogen gas will also be found useful during
and after the decarbonization of the metal by oxygen, as it will not only assist
in the removal of any remaining portions of sulphur, but will also act upon and
assist in the removal of the phosphorous or phosphoric acid, if the same
be present in the crude metal. I have observed that the forcing of atmospheric
air through molten iron so operates upon the metal, that on the completion of
the process, and after the forcing in of the air has ceased, that the metal
so operated upon is in a state of ebullition arising from the disengagement of
carbonic oxide or other gaseous matter, and that tho stirring or agitation
of the metal greatly promotes this disengagement of gas, I therefore prefer to
use the desulphurizing process, by forcing in hydrogen after the atmospheric
air or other matters containing oxygen have been used, because the mechanical
agitation produced by its passage through the metal, as well as the chemical
action it exerts, will promote the disengagement of the aforesaid gaseous
matters, and otherwise assist in the purification of the metal. Hydrogen gas,
for the purposes of my Invention, may be obtained by the action of dilute
sulphuric acid on metallic zinc, or by other well-known means.
In using the apparatus represented at Figures 1 and 2, the fluid iron from
whatever source obtained is allowed to flow into the spout h, and from thence
into the chamber c, the blast having been turned on, and the chamber heated
previous to the commencement of the process; the forcing in of the
atmospheric air and the hydrogen gas may take place at alternate intervals, or
in such manner as may be found best suited by the workman to the particular

page_text: quality of iron under treatment. Care must be taken, however, that the
bydrogen is not used for too long a time at the completion of the process, as
the absorbtion of heat by it may solidify the metal; to avoid this, and also to
obtain an additional degree of heat, the tuyere pipes f may be arranged in
pairs, and be placed near to, and at such an angle with each other, that a jet
of hydrogen propelled through one of them, and a jet of atmospheric air pro-
pelled through the other, would unite at a point a little in advance of the
orifice of each pair of tuyeres, and by the combustion of the combined gases
rapidly raise the temperature of the metal. It will be found, also, that the
slags produced in this process may be advantageously used in the next
operation; the mill scale produced in rolling bars may also be used with each
charge of metal in the proportion in which it is produced, these matters being
introduced into the vessel c at the opening h, which is then closed with a stopper.
The flame and heated gases which arise from the surface of the metal in
the chamber c will pass through the opening e, and descend on to the hearth
or floor of the chamber d, and raise its temperature; the slags and granules
of metal thrown over at the time of the boil will also collect there, while the
flame and gases will find an escape on the two opposite sides of the chamber,
through openings j, into the low chimneys k. As soon as the metal has been
purified and heated to the desired extent, the workman will raise the sliding
door, and remove the stopping of sand m, and allow the metal and the
molten slag to flow into the chamber d, in which the workman will fashion
the mass into one or more pieces with an implement such as is used in the
ordinary process of puddling, and remove the same from the puddling vessel or
chamber, to be squeezed or otherwise treated as commonly practised in the
manufacture of iron.
The malleable condition of the metal when let down from the chamber c will
render the stirring or puddling of the mass a much less laborious and more
rapid process than the puddling of crude or finery iron as at present carried
on, while the admixture of cinder with the granular mass will in the after
process of rolling give to the iron that peculiar lamelar texture considered
by some persons to be an essential peculiarity of bar iron. Or, in lieu of
the raking or stirring process, the chamber or vessel may be so con-
structed as to rotate on an axis, or to move to and fro, so that by such
movement of the vessel the metal will be prevented from becoming solidified
in a single mass, but will become broken up into fragments and mixed with
the scoria, and thus resemble an ordinary puddle ball, but of much larger
dimensions, or the mass so agitated may be turned out of the vessel into a
mould or die in which it may be subjected to powerful pressure or repeated

page_text: heavy blows by any suitable apparatus, and while still in a highly heated state
may be rolled into bars, plates, or rods.
In order that the mode by which I prefer to carry out this part of my said
Invention may be fully understood, I have represented, on the Sheet of
Drawings hereunto annexed, an apparatus suitable for that purpose at Figure
3, which is shewn partly in elevation and partly in vertical section, Figure 4
being a plan of the same. m, m, are plummer blocks supporting the shaft n,
on one end of which is keyed the frame r, the ends of which are formed into
plummer blocks *, and serve to support the axis s; on one end of this axis is a
revolving conical vessel t, formed of iron, and keyed on to the axis s; it is lined
with fire bricks t*, and has an open mouth at u; and on the opposite end of
the axis there is keyed a drum v, for the purpose of giving motion to the axis s,
the drum being made heavy enough to counterbalance the vessel t. When
the iron is sufficiently purified by the forcing therein jets of air or gas, it is to
be run by a spout from the converting vessel through the mouth u into the
vessel t, the fluid scoria produced in the process being also allowed to run in
with it; rotary motion is then communicated to the vessel t by a strap acting
on the drum v; by this means the metal will roll over the interior surface of
the vessel t, and will become granulated and mixed with 'the cinder, and may
in that state be discharged from the vessel by moving the apparatus on the
shaft n until the axis s passes from the horizontal to the vertical position.
Or, in lieu of this stirring or agitation of the metal, it may continue to have
steam or other gaseous matters forced into it in quantities not sufficient to
keep up the fluid condition of the metal, so that a spongy or granular mass
will be produced, and which may be treated in a similar manner to an ordinary
puddle ball by squeezing and rolling.
In the process of making malleable iron and steel by the forcing of oxygen
into the fluid metal, I have found that the heat evolved may be advantageously
applied to the remelting of pig iron by allowing such waste heat to enter a
reverberatory arch or chamber built in immediate connection with the converting
vessel, in which arch the pigs of iron may be so placed as to be exposed to the
full action of the heated matters which escape from the converting vessel; the
iron so melted may be afterwards rendered malleable by running it into the
converting vessel, and there forcing into it currents of gaseous oxygen, as
before described, so that the waste heat of one converting operation may be
made available for the remelting of the crude iron required for the next, or the
waste heat may be applied to a suitably constructed boiler, for the purpose of
generating steam to be used for the production of motive power, or for other
purposes in the manufacture of iron and steel.

page_text: An apparatus suitable for carrying into practical operation the remelting of
iron by the waste heat of the converting process is represented at Figures 5
and 6 of the annexed Sheet of Drawings; Figure 5 being a vertical section,
on the line E, F, of Figure 6, and Figure 6 is a horizontal section, taken on
the line X, Y, of Figure 5. A represents a mass of brickwork enclosed within
or strapped together with iron; at one end is formed the converting vessel B,
having an arched roof so made as to reverberate the flame and heated gases
on to the hearth of the melting chamber C; the converting chamber is provided
with tuyeres D in the usual way, and with proper openings for the reception
of and for the discharge of the metal therefrom. Previous to running the first
charge of metal into the converting vessel, the pig iron intended to form the
next charge is introduced through the door E into the chamber C, and as soon
as the blast is introduced through the tuyeres into the molten metal in the
converting vessel, the flame and heated gases arising therefrom will be
reverberated upon the pigs of iron in the chamber C, and melt them, the flame
finally escaping by the opening F. After the completion of the process, the
metal in the chamber C may be run off at the opening G, and may be con-
verted into iron or steel without the use of the fuel that would otherwise havo
been required for the purpose of melting the metal.
I have found that the slag or scoria which is thrown out of vessels used for
the conversion of crude iron into malleable iron or steel, by forcing air or
other gaseous matter, into the fluid metal, contains a great many small grains
of metallic iron, and that such slags also contain a large quantity of oxide of
iron, which it is desirable to recover or convert into metallic iron. For this
purpose, I either construct a chamber in immediate conuection with the con-
verting vessel, so that such slags may be thrown therein, or I construct such
chamber beyond and in connection with the remelting arch herein-before
described; in either case, the slag which is thrown therein in a heated state is
to be mixed with anthracite coal, or other carbonaceous matter, in sufficient
quantity to reduce the oxide and form metallic iron; the carbonaceous matters
used for this purpose should be thrust below the fluid scoria, in order as far as
possible to prevent combustion; the reduced metal in the state of crude iron
may be tapped out at the lower part of the chamber from time to time, and
the slag, after the metal has been obtained therefrom, may be run off at a higher
level; or in lieu of introducing solid carbonaceous matters into the fluid scoria,
coal gas, or any other carbonaceous fluid or gaseous matter may be forced
through suitable tuyeres into the fluid scoria, and the metallic iron be thereby
separated from the slag.
In order that the method which I prefer to employ for reducing the oxides

page_text: of iron, formed in the conversion of crude iron into malleable iron or steel, by
forcing currents of air or other gaseous matters into molten iron, may be fully
understood, I have shewn on the annexed Sheet of Drawings an apparatus
suitable for that purpose; Figure 7 being a vertical section of the same, taken
on the line I, J, of Figure 8; and Figure 8 being a horizontal section, on the
ine K, L, of Figure 7. The apparatus consists of an outer shell of plate
iron M, having a lining of fire bricks N, so arranged as to form the interior
into two chambers P and Q; the chamber P is provided with an opening R,
by which fluid iron is run therein, and a discharge spout at S, through which
the molten malleable metal may be drawn off, when required. The roof of the
two chambers is arched over, and the partition wall N* does not rise so high as
the roof, so that the flame and heated matters arising from the metal may pass
over the wall N, and be directed on to the lower part of the chamber Q, where
the slags thrown over during the boil will also be deposited; the flame, after
heating the chamber Q, makes its escape by the openings T, which are formed
on opposite sides of the chamber. Atmospheric air is to be forced through the
tuyeres U into the fluid iron, whereby it becomes highly heated and converted
into malleable iron or steel, a portion of the metal being formed into an oxide,
which combines with silicon and other substances present, and forms by such
union a fluid slag or cinder. When it is judged that the metal is sufficiently
decarbonized and purified it may be drawn off at the opening S, which should
be closed with a lump of moist loam as soon as the metal has run out; the
workman will then open the door V, and with an iron rod remove the stopping
of loam from the opening W, and allow the fluid cinder to flow into the
chamber Q, which is provided also with tuyere pipes at X, through which coal
gas, the waste gases from the blast furnace or other carbonaceous gases are
forced, so as to bubble up among the particles of fluid cinder, and whereby the
oxide of iron will be cemented or converted into metallic iron; the fluidity of
the cinder may be increased by the use of lime, salt, soda, or other fluxes, so
as to favour the subsidence of the fluid iron, after which the metal and refuse
cinder may be run off at the discharge hole Y. In lieu of the carbonaceous
gases, any fluid or powdered substances capable of yielding carburetted
hydrogen or other carbonaceous gases may be used; but where it can con-
veniently be effected, I prefer to reduce the fluid oxide of iron or cinder by
forcing into it the carbonic oxide given off in excess from the ordinary blast
furnace, by conveying such gases by means of a pipe situated at a suitable
height in the blast furnace, and communicating directly with the tuyeres, the
fluid cinder being in that case of no greater height above the orifice of the
tuyeres than the pressure in the blast furnace will readily overcome. Although

page_text: I have described and prefer to use a double chamber, it will be obvious that
the reduction of the metallic oxide contained in the fluid cinder may be effected
in the chamber used to decarbonize the iron, by allowing the carbonaceous
gases to enter by the same tuyeres that are used for the air.
I have also found that the grains or lumps of metallic iron may be readily
separated by crushing the spongy slags when cold, and sifting or winnowing
the crushed matter, or by the use of magnets. I have also found the rich
oxydized slags, produced in the converting vessel, useful in preventing the
injurious effects of mineral fuel in the furnaces employed in reheating or
retaining the heat of ingots or masses of metallic iron and steel that have been
made from crude iron by forcing currents of air or other gaseous matters
therein, are generally more or less spongy or cellular on their external surfaces.
I therefore throw on to such ingots or masses of iron and steel, when in the
reheating furnace, some broken slags, so that they may fuse and run, or spread
. over the surface of the ingots, or I form a shallow bath on the bed of the
reheating furnace, in which the ingots may be placed, and be turned over so
as to become coated with the fluid slag contained therein, and be thus defended
from the action of the vapours of the furnace. It will also be found that the
cavities on the surface of the ingots or masses will, in consequence of the
presence of the fluid scoria, be easier welded or closed up, and the bar of iron
or steel thereby improved. In this way borax, glass, or other saline or vitreous
matters may be used to defend the surface of the ingots or masses of iron and
steel, and assist in the closing up of any fissures or cavities that originally
existed in them, or which may be made during the hammering or rolling of
such ingots or masses of metal.
Having described the manner in which the several parts of my said Invention
may be carried into practical operation, I desire it to be understood that I do
not confine myself to the precise details herein-before described, but what I
claim is,
First, the puddling or granulating iron mixed with fluid cinder in a chamber
or vessel without the use of fuel, such iron having been decarbonized while in
a fluid state, by forcing into it atmospheric air, steam, or hydrogen gas.
Second, I claim the application of streams of hydrogen gas into fluid iron,
previous to puddling such fluid iron, without the use of fuel, as herein
explained.
Third, I claim the. granulating and mixing of molten malleable iron with
fluid cinder or scoria in revolving or moving vessels, without using fuel to heat
such vessel or the iron therein.
Fourth, I claim remelting pig iron in a reverberatory or other suitable

page_text: chamber, by means of the heat given off in the process of converting crude
iron into malleable iron or steel by streams or jets of air, or steam forced
through fluid crude iron.
Fifth, I claim the means herein described of obtaining metallic iron from
the fluid cinder or scoria produced by forcing air or steam into fluid iron and
matters containing iron.
In witness whereof, I, the said Henry Bessemer, have hereunto set my
hand and seal, this Nineteenth day of February, in the year of our
Lord One thousand eight hundred and fifty-seven.
Witness,
JA. ADDINGTON,
12, Cursitor S, Chancery Lane.
HENRY BESSEMER. (L.s.)