CERTAIN NEW PROCESSES AND NEW MODES OF EMPLOYING PROCESSES ALREADY KNOWN APPLICABLE TO METAL- LURGY OR THE MANUFACTURING OF METAL OR METALS, NOT ONLY FROM THEIR METALLIC STATE OR STATES, TO THE COMPLETION OF THE VARIOUS ARTICLES OR UTENSILS USUALLY MADE, OR WHICH MAY BE MADE, OF SUCH METAL OR METALS; ALSO CERTAIN NEW FURNACES, OR IMPROVEMENTS ON FURNACES, APPLICABLE TO THE ROASTING OR PRE- PARING OF ORES FOR THE PURPOSES OF METALLURGY, AND TO THE PREPARING OR MAKING OF COKES AND CHARCOAL, AND MINERAL AND VEGETABLE TAR, AND TO OTHER USEFUL PURPOSES
Year: 1800

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME. I, DAVID
MUSHET, of the City of Glasgow, in the County of Lanark, Scotland, Gentle-
man, send greeting.
WHEREAS His present Majesty King George the Third, by His Letters
Patent under the Great Seal of Great Britain, bearing date at Westminster,
the Thirteenth day of November now last past, hath given and granted unto
me, the said David Mushet, my executors, administrators, and assigns, special
licence, full power, sole privilege and authority, to make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, during
the term of years therein expressed, 'my Invention of "CERTAIN NEW PROCESSES
AND NEW MODES OF EMPLOYING PROCESSES ALREADY KNOWN APPLICABLE TO METAL-
LURGY OR THE MANUFACTURING OF METAL OR METALS, NOT ONLY FROM THEIR METALLIC
STATE OR STATES, TO THE COMPLETION OF THE VARIOUS ARTICLES OR UTENSILS USUALLY
MADE, OR WHICH MAY BE MADE, OF SUCH METAL OR METALS; ALSO CERTAIN NEW
FURNACES, OR IMPROVEMENTS ON FURNACES, APPLICABLE TO THE ROASTING OR PRE-
PARING OF ORES FOR THE PURPOSES OF METALLURGY, AND TO THE PREPARING OR
MAKING OF COKES AND CHARCOAL, AND MINERAL AND VEGETABLE TAR, AND TO OTHER
USEFUL PURPOSES;" in which said Letters Patent there is contained a proviso
obliging me, the said David Mushet, by an instrument in writing under my
hand and seal, to cause a particular description of the nature of my said
Invention, and in what manner the same is to be performed, to be inrolled in
His Majesty's High Court of Chancery, within four calendar months next

page_text: after the date of the said recited Letters Patent, as in and by the same
(reference being thereunto had) may more fully and at large appear.
NOW KNOW YE, that I, the said David Mushet, in compliance with
the said proviso, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, is particularly described and
ascertained in the Drawings hereunto annexed, and the following description
of them, and of the said process or processes (that is to say :-
The general principles of my process or processes are the fusion of malleable
iron, or of iron ore, in such manner and by such means as immediately to
convert them into cast steel, and likewise in certain cases the after cementation
of this steel to give it malleability and the property of welding, in order to fit
it for such purposes as require steel possessing those properties. The principles
can be acted upon for the production of the various qualities of steel in a
variety of ways, but the principle of my Invention, and the mode of operation,
may be fully understood by the instances which I shall adduce, and which will
enable any person to perform the same, and to vary and alter the mode of
operation according to his intention and the particular quality of steel he may
wich to manufacture. Thus, cast steel may be made by taking any conve
nient quantity of malleable iron, according to the size of the furnace and
crucible or crucibles to be employed, and introducing it into the crucible or
crucibles along with a proper proportion of charcoal, charcoal dust, pit coal,
pit coal dust, black lead or plumbago, or of any substance containing the
coally or carbonaceous principle; but in general charcoal, pit coal, or pit coal
cokes especially, if prepared in the manner herein-after described, will be
found to answer best. For this process not only bar iron may be employed,
but also what is commonly called scraps or waste iron; but when the latter is
used, a little more carbonaceous matter must be added to the mixture to revive
the rust or oxyde of iron adhering to the scraps. The mixture in the crucible
or crucibles must then be put into a furnace capable of giving a sufficiently
intense degree of heat to run down or fuse the mixture, which must then be
poured out into the bar, ingot, or other moulds, according as the manufacturer
intends to produce bars or ingots, or various articles or utensils that are or may
be made of cast steel, for the whole iron, by fusion with the charcoal or other
substances or things containing carbonaceous matter, will be found to have
passed into the state of cast steel. If cast into bars or ingots, and a proper
quantity of charcoal, or other substances or things containing carbonaceous
matter. had been employed. such bars or ingots will be found in a state ready
to take the hammer, and to be drawn or rolled into other shapes according to
the intention of the manufacturer. In some cases, especially where a heavy

page_text: charge is to be run down, the crucibles must be previously properly disposed
in the furnace, and the mixture introduced into them afterwards by the process
before described, and which may be varied with circumstances by any prudent
operator. Cast steel may be made in a few hours, which, by the process or
processes hitherto discovered, has usually required many days, and sometimes
weeks, for cast steel, by the common method of manufacture, has been
hitherto made from bar steel, which had previously required for its own
conversion into that state from the state of bar iron or scrap iron a tedious
cementation with charcoal in a furnace constructed for the purpose, and
usually known among manufacturers by the name of a converting furnace.
It cannot here escape observation that this is not the only saving in point
of time and expence gained by my process or processes, for when I meet with
or procure iron stones or iron ores sufficiently rich and free from foreign mix-
tures, I save even the time and expence necessary for the conversion of such
ironstone or iron ore, first into cast or pig iron, and afterwards, by a tedious
and expensive process, accompanied with a great waste of metal, into .bar iron.
For such ore or ironstones, being previously roasted .or.torrified, when that
process may be found necessary, which will often happen, may be substituted
for the bar iron, scrap, or-waste iron, as before described, and the result will be
cast steel, if a proper quantity.of.charcoal, charcoal dust, pit,coal, pit coal.dust;
plumbago or black lead, or of any substance or things containing, carbonaceous
matter, has been used. For the common and ordinary qualities, of cast steel a
much smaller quantity of carbonaceous matter,is.requisite in the,mixture, than
perhaps would have been suspected before my Invention. When charcoal
.
from wood is employed, a seventieth to a ninetieth of the weight of the iron
will generally be found sufficient. When the quantity of the carbonaceous
matter or principle exceeds one seventieth, and is increased to from one
sixtieth to one fortieth, or more of the weight of the iron, the steel becomes so
completely fusible that it may be run into moulds of any shape, and, be, capable
afterwards of being filed and polished. Hence, by casting, may be constructed
stoves, grates; kitchen utensils, many kinds of wheels and millworks, a great
variety of small machinery, and many other articles, which could not be so
made by the processes now in use, and which way of making such articles
constitutes a part of my Invention. By my process various kinds of steel,
differing as much from each other in their qualities, as the various kinds of
pig, or cast iron differ from each other,, can be formed by merely varying the
proportion of carbonaceous matter. Cast, steel of the common and ordinary
qualities is too volatile when in fusion to, admit of, being run into any shape,
except straight moulds of.a considerable diameter; but steel of such density as

page_text: to admit of being cast into any form may be produced by my process, by
increasing the quantity of charcoal or matter containing the carbonaceous
When I wish to
principle, and then fusing the mixture as before directed.
produce qualities of steel softer than is usually manufactured by the common
processes, I find it best to use a small proportion of charcoal, sometimes so little
as a two hundredth part of the weight of the iron. Steel, produced with any
proportion of charcoal not exceeding a one hundredth, will generally be found
to possess every property necessary to its being cast into those shapes which
require great elasticity, strength, and solidity; it will also be found generally
capable of sustaining a white heat, and of being welded like maleable iron; and
indeed, as the proportion of charcoal or other carbonaceous matter is reduced,
the qualities of the steel will be found to approach nearer to those of conimon
maleable iron. By further pursuing the principle of my new Invention, I fuse
down maleable bar or scrap iron in a crucible or crucibles, without any visible
addition of carbonaceous matter, and run it into bar, ingot, or other moulds.
In this state the metal is nearly of the same quality as when put in, only
altered by the combination of a small portion of carbonaceous matter, which
the iron, by its chemical affinity, attracts from the ignited fuel, or from the
ignited carbonic gas of the furnace, and which enters by the mouth or through
the pores of the crucible or crucibles, probably dissolved in caloric at a very
high temperature. But whether so dissolved or not, the fact is that a propor-
tion of the carbon passes from the fire into union with the iron, and thereby
converts it into an extremely soft steel. Besides the different modes of operation
above specified, I further reduce iron ore, bar iron, or scrap iron, by the addi-
tion of lime or chalk, or other carbonates or of carburets, with clay, glass, and
other fluxes in various proportions, and form all the various qualities of steel
formerly enumerated. If the various kinds and qualities of steel obtained by
the process or processes above mentioned be introduced into the common con-
verting or other steel furnaces, in contract with carbonaceous matter, or with
earths, and heated for five days, or more or less, according to the thickness of
the bars or other forms, and the quantity introduced, the bars, ingots, or other
shapes; being then taken from the furnace, will. be found to possess all the
solldity which they formerly were possessed of as cast steel, with that property
of welding peculiar to blistered, faggot, or German steel, of the usual mode of
manufacture. By this Invention I obtain steel which, for solidity, may be
used for the purposes of cast steel, uniting at the same time the property of
welding, without destroying the solidity or quality of the metal,-a circum-
stance of the highest importance to our manufacturers. Ingots, bars, plates,
and every shape into which this steel is cast, rolled, or hammered, will

page_text: be possessed of uniformity of quality without those numerous reeds,
flaws, blisters, and disjoined laminæ found in steel made by the processes
in use before my Invention. When pit coal cokes are to be used in any of
the foregoing operations, either in mixture with the ore or with the iron or for
fuel in the furnaces, in which the crucibles containing the mixture are
exposed to the action of the fire, it is of the utmost importance that the cokes
be properly prepared. The process which I have found to answer best for
this purpose, though common cokes will also do, is founded upon the principle
that all access of oxygen to the coals to be coked should be prevented. "This
end is gained by preparing the cokes in iron vessels in the same manner as.
wood is now charred for the purpose of being employed in the manufacture of
gunpowder, the bitumens, or coal tar as it is commonly called, which is
volatilized from the coals to be coked by the heat applied to the exterior of the
iron vessel or other chamber containing the said coals, is thus saved, instead of
being burnt or dissipated in the atmosphere, as is the case in the common
process of coaking, in which the coals are exposed to combustion in open
heaps, and which also partially, though in a less degree, takes place in
the process commonly known by the name of Lord Dundonald's process for
preparing coal tar. But as it is of importance in large manufactories that the
process of coaking should keep pace with the other processes connected with
metallurgy, that a sufficient quantity of cokes may always be at command of
an uniform quality, it may be necessary in many cases to prepare furnaces
somewhat different in construction but agreeing in principle with the one for
preparing charcoal which has above been generally alluded to. The following
construction of a coaking furnace, but which may be varied in form according
to the form of the scite of particular manufactories and other circumstances,
will be found calculated to produce cokes of an excellent quality, and at the
same time a saving of all the bitumen or coal tar volatilized by the process;
and, where circumstances render it adviseable, will admit of metallic ores being
roasted at the same time along with the coals to be coked in the interior of
the structure, or with such a proportion of coally matter as simply to torrify
the ores or ironstones for the blast furnace.
Figure 1st of the Drawing hereunto annexed represents an end section
of the furnace. A, the ash-pit, six feet wide at bottom and narrowing
to four feet at the bearer, which is placed across to support the furnace
bars. B, the iron bearer. C, the fire-place. D, D, the commencement
of the flue which surrounds the interior building of the furnace. six inches
high and two feet broad. Of these flues there are eight in the length
of the present furnace, and there number may be extended or dimi-
:

page_text: nished in proportion as the furnace is constructed of a larger or of a
smaller size. As these flues conduct the flame and heat from the ignited
coals upon the grates, the interior part of the furnace and its contents become
thoroughly heated. The vapour arising from the coals or ores exposed to
ignition, together with the flame and smoke of the coals used for fuel, escape
by the aperture E, of which there are also eight in the extreme length of the
present furnace. Any greater length of chimney may be added above the
present as circumstances may point out; the same apertures may also serve to
charge the furnace. F, a small door in the front of the furnace, which serves
to empty it of it's contents. G, plate of cast iron, which serves for the
bottom of the furnace, and on which the side walls are built. The under
surface of this plate is cast with a number of small protuberances, which when
covered with a coating of clay keep hold of the same and prevent the oxydator
of 'the iron, although exposed to a considerable degree of heat. In place of
an iron plate an arch of fire bricks on edge may be substituted, particularly
where there is no scarcity of small coal or other fuel. Instead of making the
sides of fire bricks as represented in the Drawing, cast iron plates with flanges
may be substituted, which will transmit the heat with greater facility than
brick.
Figure 2nd, top view of the furnace cut across at the spring of the
arch. D, D, D, 'D, D, D, the side flues as they rise from the sides of the
furnace, to convey the heat and flame betwixt the inner and outer arches.
E, E, E, apertures by which the smoke and vapour arising from the side flues
and from the cavity of the furnace makes it escape. 'Their dimensions are
twelve inches, and may be either round or square. In order to facilitate the
ignition of the material acted upon for distillation, it will be necessary in
charging the furnace to introduce into every second flue a wooden plug to
rest with its under end-upon the bottom of the furnace, which are withdrawn
when the furnace is filled. The fire is then laid upon the grates at C, and fed
with culm or waste coals. In a short time the cavity of the furnace or coaker
and its contents become completely ignited; vapour and smoke are disengaged
in large quantities, and carried off through the apertures.E, E, E.
Figure 3d represents a furnace of a similar shape, and constructed upon the
same principles, but which is calculated to collect and condense the smoke and
vapour into pit coal tar, which is volatilized in this new.process of charing. A,
the ash-pit. B, the bearing tar or plate. C, the fire-place. .D, D, the side flues,
as described in Figure 1st. .E, E, flues by which, the smoke arising from the
fach may be easily conducted into adjoining chambers, and the soot collected for
forming. lamp black. This is easily facilitated, by shutting the corresponding

page_text: dampers at the furnace top till nearly all the smoke has entered the chamber.
F, the furnace bottom, an arch of fire bricks upon edge, in place of of a cast
iron plate described in Figure 1st. G, view of one of the apertures by the
smoke and vapour rises from the cavity of the furnace. The damper is kept
shut upon the top of the pipe or chimney H, and the smoke is conducted
along the horizontal pipe I, and enters the cylinder K. The external cylinder
L, L, being constantly kept full of cold water condenses the smoke in K,
which falling down the internal sides of the tapered cylinder issues out below,
and is conducted by means of a rhone or pipe to a general receiver. A fur-
nace of the present size has eight flues in all, four of which serve to conduct
the smoke of the cavity to the condensers. The other four are simply
mounted with dampers for alternately forcing the smoke of the fuel into the
vault M, and for admitting the free circulation of air necessary to maintain
the combustion of the grates.
In operating with furnaces of this construction, I shall remark upon the
whole, that when the furnace without the condensing apparatus is used, the
cokes preparing in the interior of the furnace ought to be exposed some hours
after the smoke has disappeared, but the necessary length of time will
immediately depend upon the quality of the coal submitted to be coked.
The same precaution is necessary in using the condensing furnace; for this end
all the dampers ought to be opened and remain so for a considerable space
after the smoke and vapour have disappeared.
In witness whereof, I, the said David Mushet, have hereunto set my hand
and seal, this Seventeenth day of December, in the year of our Lord
One thousand eight hundred.
Taken and acknowledged by the said
David Mushet, at Glasgow, Scotland,
the Seventeenth day of December,
One thousand eight hundred, before
DAVID MUSHET. (L.S.)
MAT
BAILLIE,
J. P.
Inrolled the Third day of February, in the year of our Lord One
thousand eight hundred and one.