A WAY OF MAKING MALEABLE IRON FROM PIG OR SOW METAL, COMMONLY CALLED CAST IRON, BY A METHOD INTIRELY NEW
Year: 1761

page_text: WOOD, of Wednesbury, in the County of Stafford, Ironmaster, send greeting.
WHEREAS I, the said John Wood, did by Petition to Ilis present Majesty
humbly shew that I had invented "A WAY OF MAKING MALEABLE IRON FROM PIG
OR SOW METAL, COMMONLY CALLED CAST IRON, BY A METHOD INTIRELY NEW,"
and therefore, as well as for other reasons contained in the said petition, did
pray His said Majesty to grant unto me, my executors, adiñors, and assigns,
His Royal Letters Patent for the sole use and benefit of the said Invention,
within that part of Great Britain called England, Dominion of Wales, and
Town of Berwick-upon-Tweed, and also within His Majesty's Plantations and
Colonies abroad, for the term of fourteen years; to the prayer of which
petition His said Majesty was most graciously pleased to condescend, and
Leters Patent agreable thereto have accordingly passed the Great Seal.
NOW KNOW YE, that I, the said John Wood, in compliance with and in
performance of a proviso or condition contained in the said Letters Patent, do
hereby describe and ascertain my said Invention in manner following, viz' :-
In my process for converting brittle iron cast into pigs or masses of any
other form (commonly called cast metal) into a maleable state, with fires of
pitt or fossil coal, several operations are performed, some of which are
preparatory, and others more peculiarly essential to my method of working.
The preparatory operations are various, either according to the nature of
the cast iron applied, or else according to the intention of the operator, to
make the malleable iron hard or soft, or of such other qualities as are required
for different uses. By these preparatory operations the iron is prepared and

page_text: fitted for those other operations which are essentially necessary in my way of
working, and peculiar thereto, which are constantly performed in the same
manner, and having been by me invented, therefore distinguish my method
from all others that have been put in practice or discovered.
By these last-mentioned operations, which are more peculiar to my method,
the cast iron is refined and rendred pure, and its malleability is finished and
perfected; and as the fuel used is raw pitt coal, these operations are therefore
performed in close vessells, by which means the iron is prevented from coming
into immediate contact with the fuel or its flame, and preserved from the acid
and sulphureous steams of the coal, which are found to have pernicious effects
on this metal, and to obstruct its being brought into a malleable state.
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"The vessells which I use in these operations are potts, moulds, or covers,
"made of such materials as will best resist the force of the fire; some are of
pure clay when it can be had of a proper quality, others of clay earth, horse
dung, and other mixtures; the pots are baked or burnt in the fire; the
"moulds or covers are used wet, without baking.
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"
"
"These vessells I fill with cast iron, first duly prepared, and mixed when
necessary with the fluxes and other additions hereafter mentioned. The
" vessells being filled, I carefully close them up with covers of the same
"materials of which they are made; I then place them in an air furnace, and
heat them with a strong fire made with pitt or fossil coal until the
impurities contained in the iron, and the fluxes and other heterogenous
"substances applied thereto, are fused and run together into a cinder or slag,
" and the iron is brought into a tough and malleable state; I then take the
"vessells out of the furnace and work the iron into barrs or any other proper
" form under the hammer.
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As to the preparatory operations that in my process are necessary in order
to render the cast iron fit and proper for the above-mentioned operations in
close vessells, 1 perform them in several ways as below related :-
1stly. I take pig or sow iron or other cast metal; this I flourish or heat
and work in a coñon finery with a blast and a fire of raw pitt coal until it is
refined in some measure from its dross, and brought near to a malleable state,
which the artists call bringing it into nature. The iron thus flourished, I put
into close vessells, (either potts, moulds, or covers,) and further refine it, and
render it perfectly malleable in an air furnace, with fires of raw pitt coal, by
the methods before described.
2dly. To the iron thus flourished I sometimes add a due proportion of
small pieces of malleable iron, when the cast metal used was very brittle, or
the coals applied very sulphureous.

page_text: 3dly. I also take the same cast metal, and melt it down in an air furnace
with a fire of pitt coal; the melted metal I reduce into small grains (accord-
ing to art) by pouring it into water, upon a wheel or roller turned briskly
round; the granulated metal I mix with various fluxes, according to its
nature and the uses for which the iron is intended, as with iron slag or
cinder, scaled or scoria of iron, fuisible sand, and lime, kelp, soapers waste;
these I put with the granulated metal into close vessells and work them in
an air furnace, in the same manner as before related.
4thly. I also take the same cast iron formed into thin plates, these I break
into small pieces, and put them into the pots, moulds, or covers, with a due
proportion of the fluxes and additions before mentioned; the vessells being
closed and placed in an air furnace, the iron contained in them is reduced to a
malleable state, after the manner before described.
And I, the said John Wood, do hereby averr and declare that the above
is a true, full, and perfect description of the nature and practise of my said
Invention.
In witness whereof, I, the said John Wood, have hereunto sett my
hand and seal, the Eighteenth day of May, One thousand seven
hundred and sixty-one.
JOHN WOOD. (L.S.)
Sealed and delivered (upon paper duly stampt),
in the presence of
THO' COBB.
JN ADEY a Master Extraordinary in the High Court of Chancery.
Inrolled the Twenty-third day of May, in the year above written.