IMPROVEMENTS IN THE TREAT- MENT OF GAS PRODUCED BY THE DISTILLATION OF COAL, CANNEL, BITUMINOUS SHALE, BOGHEAD MINERAL, OILS, PETROLEUM, OR OTHER COMBUSTIBLE SUB- STANCES, AND FOR THE OBTAINING OF CERTAIN PRODUCTS THEREPROM
Year: 1863

page_text: LETTERS PATENT to John Leigh, of the City of Manchester, in the County of
Lancaster, Gentleman, for the Invention of "IMPROVEMENTS IN THE TREAT-
MENT OF GAS PRODUCED BY THE DISTILLATION OF COAL, CANNEL, BITUMINOUS
SHALE, BOGHEAD MINERAL, OILS, PETROLEUM, OR OTHER COMBUSTIBLE SUB-
STANCES, AND FOR THE OBTAINING OF CERTAIN PRODUCTS THEREPROM."
Sealed the 30th June 1863, and dated the 6th January 1863.
PROVISIONAL SPECIFICATION left by the said John Leigh at the
Office of the Commissioners of Patents, with his Petition, on the
6th January 1863.
I, JOHN LEIGH, of the City of Manchester, in the County of Lancaster,
Gentleman, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN THE TREATMENT OF GAS PRODUCED BY THE DISTILLATION OF COAL, CANNEL,
BITUMINOUS SHALE, BOGHEAD MINERAL, OILS, PETROLEUM, OR OTHER COMBUSTIBLE
SUBSTANCES, AND FOR THE OBTAINING OF CERTAIN PRODUCTS THEREFROM," to be
as follows:-
I pass the gas obtained by the distillation of these substances, whether pro-

page_text: duced for the purposes of illumination in the ordinary way in gasworks, or
specially to be produced for the purpose of making nitro-benzole therefrom,
through suitable vessels containing fuming nitric acid, ordinary commercial
nitric acid, or a mixture of sulphuric and nitric acids, causing the gas to be
brought into contact with these acids as much as possible, by which means
nitro-benzole and other substances are obtained, which may be used in the
arts, and by which the gas is also freed from certain impurities.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Leigh in the Great Seal Patent Office on the 4th
July 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
LEIGH, of the City of Manchester, in the County of Lancaster, Gentleman,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of January, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-sixth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said John Leigh, Her special licence, that I, the said John Leigh, my
executors, administrators, and assigns, or such others as I, the said John
Leigh, 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 Invention for "IMPROVEMENTS IN THE TREATMENT
OY GAS PRODUCED BY THE DISTILLATION OF COAL, CANNEL, BITUMINOUS SHALE, BOG-
HEAD MINERAL, OILS, PETROLEUM, OR OTHER COMBUSTIBLE SUBSTANCES, AND FOR THE
OBTAINING OF CERTAIN PRODUCTS THEREFROM," upon the condition (amongst
others) that I, the said John Leigh, my executors or administrators, by
an instrument in writing under my, or their, or one of their bands and seals,
should particularly 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
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Leigh, do hereby declare
the nature of my said Invention, and in what manner the same is to be

page_text: performed, to be particularly described and ascertained in and by the
following statement (that is to say) :-
My Invention consists in the subjection of the gas obtained in the dis-
tillation of coal, cannel, bituminous shale, boghead mineral, oils, petroleum,
or other combustible substances to the action of nitric acid, or of a mixture
of nitric and sulphuric acids, by which nitro-benzole and certain other com-
pounds are obtained, and in the course of which certain substances are
removed from the gas employed.
And for the carrying out of this my Invention I proceed in the manner
following:-Into a series of earthenware vessels of the form and arranged in
the manner of Woulfe's bottles, I introduce a quantity of fuming nitric acid, or
a mixture of commercial nitric and of sulphuric acids, and through this I pass
a current of gas produced from any of the materials before named, continuing
the operation so long as any action is exerted by the acids upon the gas.
When the operation is completed I remove the nitro-benzole and other pro-
ducts separating themselves from the acid liquid, and which acid liquid may
be employed after the removal of the products above mentioned, for purposes
where weak nitric acid or a mixture of weak nitric and oxalic acids may be
required, containing as it does a considerable quantity of the latter acid; or
the oxalic acid may be separated therefrom by well-known methods.
The process described may be used for the formation of the products of the
action of the gas or gases upon the acid or acids alone; but where the purifi-
cation of the gas or gases is desired for the purposes of illumination I prefer
to use fuming nitric acid alone, which removes from the gas or gases certain
constituents, which render the gas or gases more liable to give off smoke in
their combustion, and by which operation the odour of the gas is improved,
and under these circumstances I prefer a very brief contact of the gas or gases
with the acid. In the process described a quantity of acid vapour is mecha-
nically carried forward with the gas, which acid vapour may be brought into
contact with alkalies or mineral salts capable of removing it from the gases.
Although I have found earthenware vessels, of the form and arranged in the
manner of Woulfe's. apparatus and provided with suitable tubes, to answer in
the process described, yet any other arrangement by which the gas may be
brought into good contact with the acid or acids may be employed, and I do
not claim any particular form of apparatus for the carrying out of my said
Invention.
Where a mixture of commercial nitric acid and of commercial rectified
sulphuric acid is employed, I prefer to use one part of nitric to two parts of

page_text: sulphuric acid; and when fuming nitric acid is employed I prefer to use the
strongest.
In witness whereof, I, the said John Leigh, have hereunto set my
hand and seal, this Second day of July, in the year of our Lord One
thousand eight hundred and sixty-three.
Signed, sealed, and delivered,
by the within-named John
Leigh, in the presence of
E. J. HUGHES,
Patent Agent,
Manchester.
JOHN LEIGH. (L.S.)