AN IMPROVED MODE OF CONVERTING CAST IRON INTO SOFT MALLEABLE IRON WITHOUT CHANGE OF FORM
Year: 1859

page_text: LETTERS PATENT to John Talbot Pitman, of the American & European
Patent Offices, No. 67, Gracechurch Street, London, for the Invention
of "AN IMPROVED MODE OF CONVERTING CAST IRON INTO SOFT MALLEABLE
IRON WITHOUT CHANGE OF FORM."-A communication from abroad by
J. A. K. Eaton, of the City, County, and State of New York, in the
United States of America.
Sealed the 11th April 1860, and dated the 21st October 1859.
PROVISIONAL SPECIFICATION left by the said John Talbot Pitman
at the Office of the Commissioners of Patents, with his Petition, on
the 21st October 1859.
હા.
I, JOHN TALBOT PITMAN, of the American & European Patent Offices,
No. 67, Gracechurch Street, London, do hereby declare the nature of the
said Invention for "AN IMPROVED MODE OF CONVERTING CAST IRON INTO SOFT
MALLEABLE IRON WITHOUT CHANGE OF FORM," a communication from abroad
by J. A. K. Eaton, of the City, County, & State of New York, in the United
States of America, to be as follows:-
The nature of my Invention consists in the use of oxyd of zinc alone or
combined with the oxyd of iron as a decarbonizing agent. Instead of the pure
oxyd of zinc the crude oxyds or the carbonate may be used. Castings of any.
form of the variety called white cast iron may be packed in iron boxes,
crucibles, or otherwise, as in the well-known process of making malleable cast
iron, except that oxyd of zinc, or a mixture of oxyd of zinc and oxyd of iron is
used instead of the ordinary material, the whole being exposed to a bright red
heat in any suitable furnace, the cast iron is rapidly decarbonized at the

page_text: expense of the oxygen of the oxyd of zinc. The metallic zinc thus produced
may be allowed to distil over, and be collected as pure metal; or it may be re-
oxydized as it passes off by contact with heated air, and produce white oxyd
of zinc.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Talbot Pitman in the Great Seal Patent Office on the
21st April 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
TALBOT PITMAN, of the American and European Patent Offices, No. 67,
Gracechurch Street, London, send greeting.
year of Her
grant unto him,
the said John
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of October, in the year of our Lord
One thousand eight hundred and fifty-nine, in the
reign, did, for Herself, Her heirs and successors, give and
the said John Talbot Pitman, Her special licence that
Talbot Pitman, my executors, administrators, and assigns, or such others
as I, the said John Talbot Pitman, 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 Inven-
tion for "AN IMPROVED MODE OF CONVERTING CAST IRON INTO SOFT MALLEABLE
IRON WITHOUT CHANGE OF FORM," a communication from abroad by A. K. Eaton,
of the City, County, & State of New York, in the United States of America,
upon the condition (amongst others) that I, the said John Talbot Pitman, 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 per-
formed, 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 John Talbot Pitman, 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 :-
It consists in the use of oxyd of zinc alone, or combined with the oxyd of

page_text: iron as a decarbonizing agent. Castings of any desired form of the variety
called white cast iron may be packed in iron boxes, crucibles, or otherwise, as
in the well-known process for making malleable cast iron, except that oxyd of
zinc, or a mixture of oxyd of zinc and oxyd of iron is used instead of the
ordinary material, the whole being exposed to a bright red heat in any suitable
furnace, the cast iron is rapidly decarbonized at the expense of the oxygen of
the oxyd of zinc. The metallic zinc thus produced may be allowed to distil
over, and be collected as pure metal; or it may be re-oxydized as it
by contact with heated air, and produce white oxyd of zinc.
passes off
The cast iron after being subjected to this process has the softness, flexibility,
and malleability of wrought iron. It is not necessary or desirable that the
pure oxyd of zinc be used, since the crude oxyds, or even the carbonate,
may be as successfully used, and with much greater economy. An elevated
temperature readily converts the carbonate of zinc into an oxyd of that metal.
The oxyd of zinc acts much more thoroughly as a decarbonizing agent than
oxyd of iron, since the volatile metallic zine passes off as soon as formed,
presenting fresh oxyd to the surface of the iron, whilst the oxyd of iron, if that
substance be used alone, by its reduction, surrounds the casting with a fixed
envelope of porous iron, which greatly retards the process of decarbonization.
Having now herein fully described the Invention as communicated to me,
what I claim and desire to secure under the herein-before in part recited
Letters Patent, is, the employment of oxyd of zinc in the production of
malleable iron castings in the manner specified, so that the articles whilst
under this treatment will have continually presented to them a fresh supply of
decarbonizing material.
In witness whereof, I, the said John Talbot Pitman, have hereunto set
my hand and seal, on this First day of March, Anno Domini, One
thousand eight hundred and sixty.
JOHN TALBOT PITMAN. (L.S.)