IMPROVEMENTS IN MAKING IRON CASTINGS
Year: 1859

page_text: LETTERS PATENT to Sir Francis Charles Knowles, of Lovell Hill, in the
County of Berks, Baronet, for the Invention of "IMPROVEMENTS IN
MAKING IRON CASTINGS."
Sealed the 4th January 1860, and dated the 7th July 1859.
PROVISIONAL SPECIFICATION left by the said Sir Francis Charles
Knowles at the Office of the Commissioners of Patents, with his Petition
on the 7th July 1859.
I, Sir FRANCIS CHARLES KNOWLES, of Lovell Hill, in the County of Berks,
Baronet, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN MAKING IRON CASTINGS," to be as follows:-
The process which I employ for the purification of the iron used in the
castings, and the strengthening of the castings themselves, as well as giving to
them cleaner edges and surfaces and better defined mouldings, is the use
of nitrate of soda or nitrate of potash in the ladle or other receptacle for the
metal before casting. The quantity which I employ depends on the degree or
state of carbonization of the metal used, on its supposed impurities, and on the
degrees of hardness or softness sought to be obtained in the castings; there-
fore I do not confine myself to any definite quantity, but the impurities and
carbon being known, it is easy to calculate, from the oxygen required to oxidize
the former completely, and to saturate the requisite quantity of carbon, how
much of the nitrate is to be used. The nitrate must be stirred or agitated
among the molten metal until all visible chemical action shall have ceased.
I

page_text: do not restrict myself from using other substances either before or after
these nitrates, or in conjunction with them where any other special quality
is to be obtained, as, for example, any of the cyanides or ferro-cyanides, if the
decarbonization should by accident be carried too far.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Sir Francis Charles Knowles in the Great Seal Patent
Office on the 7th January 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, Sir FRANCIS
CHARLES KNOWLES, of Lovell Hill, in the County of Berks, Baronet, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of July, in the year of our Lord One
thousand eight bundred and fifty-nine in the twenty-third year of Her reign.
did, for Herself, Her heirs and successors, give and grant unto me, the
said Sir Francis Charles Knowles, Her special licence that I, the said Sir
Francis Charles Knowles, my executors, administrators, and assigns, or such
others as I, the said Sir Francis Charles Knowles, my executors, adminis-
trators, 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 "IMPROVEMENTS IN MAKING IRON CASTINGS," upon the condition (amongst
others) that I, the said Sir Francis Charles Knowles, my executors or administra-
tors, 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 Inven-
tion, 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 Sir Francis Charles Knowles, do
hereby declare the nature of my 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:-
The process which I employ for the purification of the iron used in the
castings and the strengthening of the castings themselves, as well as giving to
them cleaner edges and surfaces and better defined mouldings, is the use of
nitrate of soda or nitrate of potash in the ladle or other receptacle for the

page_text: metal before casting. The quantity which I employ depends on the degree or
state of carbonization of the metal used, on its supposed impurities, and on the
degree of hardness or softness sought to be obtained in the castings; therefore
I do not confine myself to any definite quantity, but the impurities and carbon
being known, it is easy to calculate from the oxygen required to oxydize the
former completely, and to saturate the requisite quantity of carbon how much
of the nitrate is to be used. The nitrate must be stirred or agitated among
the molten metal until all visible chemical action shall have ceased. I do
not restrict myself from using other substances either before or after these
nitrates, or in conjunction with them, where any other special quality is to be
obtained, as, for example, any of the cyanides or ferro-cyanides if the decarbo-
nization should by accident be carried too far.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I claim, the purification
of molten cast iron as aforesaid, and I claim the said purification with nitrate
of soda or nitrate of potash alone or jointly with other substances, and whether
the metal be used directly or remelted after being run into pigs or moulds.
In witness whereof, I, the sd Sir Francis Charles Knowles, have here-
unto set my hand and seal, this Fourth day of January, One thousand
eight hundred and sixty.
FRANCIS CHARLES KNOWLES. (L.S.)