AN IMPROVED MODE OF OBTAINING NITROUS ACID GAS FOR MAKING SULPHURIC ACID
Year: 1861

page_text: LETTERS PATENT to Robert Laing and George Horwood Cossins, of Ince,
near Wigan, in the County of Lancaster, for the Invention of "AN
IMPROVED MODE OF OBTAINING NITROUS ACID GAS FOR MAKING SULPHURIC
ACID."
Sealed the 11th January 1862, and dated the 19th July 1861.
PROVISIONAL SPECIFICATION left by the said Robert Laing and George
Horward Cossins at the Office of the Commissioners of Patents, with
their Petition, on the 19th July 1861.
We, ROBERT LAING and GEORGE HORWOOD COSSINS, of Ince, near Wigan,
in the County of Lancaster, do hereby declare the nature of the said Inven-
tion for "AN IMPROVED MODE OF OBTAINING NITROUS ACID GAS FOR MAKING
SULPHURIC ACID," to be as follows:-
Our Invention relates to certain methods for decomposing nitrate of soda or
nitrate of potash, for the purpose of obtaining nitrous acid gas therefrom, to
be used in the ordinary and well-known way for making sulphuric acid, and
consists, first, in the use of arsenious acid, or arsenic acid to decompose nitrate
of soda, or nitrate of potash, by which means we obtain nitrous acid gas, fit to
be used in the manufacture of sulphuric acid and arseniate of soda, or arseniate
of potash as a residuum.
Secondly, in the use of ground or powdered chrome iron ore to decompose·
nitrate of soda, or nitrate of potash, by which means we obtain nitrous acid
gas, as above, and chromate of soda or chromate of potash as a residuum.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Laing and George Horwood Cossins in the Great
Seal Patent Office on the 17th January 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, wc, ROBERT
LAING and GEORGE HORWOOD COSSINS, of Ince, near Wigan, in the County of
Lancaster, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth day of July, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fifth year of
Iler reign, did, for Herself, Her heirs and successors, give and grant unto
us, the said Robert Laing and George Horwood Cossius, Her special licence
that we, the said Robert Laing and George Horwood Cossins, our executors,
administrators, and assigns, or such others as we, the said Robert Laing and
George Horwood Cossins, our 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 "AN
IMPROVED MODE OF OBTAINING NITROUS ACID GAS FOR MAKING SULPHURIC ACID,"
upon the condition (amongst others) that we, the said Robert Laing and
George Horwood Cossins, our executors or administrators, by an instrument in
writing under our, or their, or one of our or their hands and seals, should par-
ticularly 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said George Horwood Cossins, do hereby
declare the nature of our said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement (that is to say):-
First, we use arsenious acid or arsenic acid to decompose nitrate of soda or
nitrate of potash. If nitrate of soda be decomposed, we prefer to use the pro-
portions of seven parts nitrate soda to five parts of arsenious acid, or six parts
of arsenic acid. If nitrate of potass be decomposed, we prefer to use the pro-
portions of seven parts nitrate of potash to four parts of arsenious acid.
In performing the above decompositions, we prefer to use a muffle or retort,
so placed as to be heated by the furnaces or kilns in which the pyrites are
burnt, and to allow the gas to issue from the retort through a small tube bent

page_text: in the direction of the draught. Our object in using a close vessel and a tube,
is to prevent any sulphurous acid gas from coming in contact with the mixture,
as in that case sulphate of soda would be formed, which would vitiate the
result.
Secondly, we use chrome iron ore to decompose nitrate of soda or nitrato
of potash.
In performing this decomposition the proportions must be regulated by the
per-centage of chromium contained in the ore employed.
For the purpose of effecting this decomposition we prefer to use a small
reverberatory furnace separate from the pyrites kilns.
Having thus described the nature of our said Invention, and the manner in
which the same is to be performed, we would have it to be distinctly understood
that we do not claim any particular mode or method for carrying out the same,
and that all we claim is, the use and application in the manufacture of
sulphuric acid of the nitrous acid gas arising from the decomposition of nitrate
of soda, or of nitrate of potash by arsenious acid, arsenic acid, or chrome
iron ore.
In witness whereof, I, the said George Horwood Cossins, have here-
unto set my hand and seal, this Fourteenth day of January, in the
year of our Lord One thousand eight hundred and sixty-two.
GEORGE HORWOOD COSSINS. (L.S.)
Signed, sealed, and delivered, by the within-
named George Horwood Cossins, in the
presence of
E. J. HUGHES,
Patent Agent,
Manchester.