IMPROVEMENTS IN THE MANUFACTURE OF ILLUMINATING GAS
Year: 1856

page_text: LETTERS PATENT to George Clark, of Great Cambridge Street, Hackney
Road, in the County of Middlesex, Gas Engineer, for the Invention of
PROVISIONAL SPECIFICATION left by the said George Clark at the
Office of the Commissioners of Patents, with his Petition, on the 19th
May 1856.
I, GEORGE CLARK, of Great Cambridge Street, Hackney Road, in the
County of Middlesex, Gas Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF ILLUMINATING GAS," to
be as follows:-
The object of this Invention is to enable public institutions, private families,
and persons on shipboard to manufacture gas for their own consumption,
without the necessity for costly apparatus or the exercise of skill in the
manufacture. To this end I prepare a marketable tar or oily product by
distilling rich bituminous coal or other substance at a low temperature in a
retort, and I apply this oil in its crude state to the production of illuminating
gas, by causing it to flow in a small stream into a retort set over a fire place,
like a common copper or boiler. The oil when subjected to heat in this retort
will be converted into gas, and it may then be conducted directly to the

page_text: burners to be consumed, or passed first through water or other cooling or
purifying medium. The supply of oil to the gas retort must be regulated by a
tap, so as to ensure a supply commensurate with the consumption, and I
propose in some cases to make the supply self-adjusting by connecting the
supply cock with a gas regulator, which, as the pressure of the
therein, will proportionately reduce the supply of oil to the retort.
gas increases
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Clark in the Great Seal Patent Office on the
19th November 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
CLARK, of Great Cambridge Street, Hackney Road, in the County of Middlesex,
Gas Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth day of May, in the year of our Lord One
thousand eight hundred and fifty-six, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
George Clark, Her special license that I, the said George Clark, my
executors, administrators, and assigns, or such others as I, the said George
Clark, 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 MANU-
¡FACTURE OF ILLUMINATING GAS," upon the condition (amongst others) that I,
the said George Clark, by an instrument in writing under my hand and seal,
should particularly describe and ascertain the nature of the said Invention, and
in what manner the same was to be performed, and causo 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 George Clark, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawing hereunto annexed (that is
to say):
The object of this Invention is to provide a means for enabling the servants
of public institutions, and private families, and also ships' crews, to manufacture

page_text: gas for their own consumption in an economical and efficient manner, without
the necessity for costly apparatus or the exercise of skill in the manufacture.
To this end I provide a gas-yielding oil, which, unlike the vegetable oils
heretofore proposed to be used in the manufacture of illuminating gas, does not
contain oxygen, and will not, therefore, yield in any appreciable quantity
carbonic acid gas; and, on the other hand, does not like coal tar (the well-
known oily product produced by the distillation of coal in ordinary gas-making)
contain sulphur. From an oil thus free of oxygen and sulphur (the presence
of which in gas renders an elaborate system of purification absolutely neces-
sary) I generate illuminating gas, and that in general at a rate that will about
equal the rate of consumption, so that the use of a gas-holder where space is
an object may be dispensed with. The oil I prepare by distilling the rich
bituminous coal, known as Boghead coal, or other bituminous substance, in a
retort heated to a dull red heat, and as the vapour comes over, I condense
it in any well-known manner. This oil I apply in its crude state to the
production of illuminating gas by causing it to flow in a small stream on to
lumps of fire-brick, coke, or other porous matter, placed in a suitable retort
set in a furnace, as shown in front clevation and cross section in the accom-
panying Drawing. The oil is subjected in this retort to a cherry red heat, and
being distributed over a large heating surface will be quickly converted into
gas, and it may then be conducted directly to the burners to be consumed, or
passed first through water or other cooling or purifying melium. The supply
of oil to the gas retort must be regulated by a tap or valve, so as to ensure a
supply commensurate with the consumption, and I propose in some cases to
make the supply self-adjusting, by connecting the supply cock with a gas
regulator, which, as the pressure of the gas increases therein, will propor-
tionately reduce the supply of oil to the retort. The oil enters the retort
through a syphon or any other convenient form of "seal valve," communicating
with the supply pipe and the interior of the retort.
I would remark that I do not claim as any part of my Invention the dis-
tilling of bituminous substances at -a, low temperature as above described, and
thus obtaining a mineral oil free of sulphur; neither do I claim the appa-
ratus shewn for the conversion of mineral oil into illuminating gas; but,
inasmuch as I have found by repeated experiments that an oil so distilled is
eminently suited to the production of illuminating gas, both from its small
cost in comparison with vegetable oils, its freedom from deleterious com-
pounds, and its property of volatilizing at a low temperature (whereby the
rapid destruction of the retorts is prevented,) it is the introduction of this
oil into the gas manufacture, and particularly in those ocalities and situations

page_text: -(as for example on ship board), where a public supply is not available to the
consumer, that constitutes the subject matter of my Invention.
Having now set forth the nature and object of my Invention of "Im-
provements in the Manufacture of Illuminating Gas," and explained the
manner of carrying the same into effect, I wish it to be understood that under
the above in part recited Letters Patent, I claim the application to gas-making
of mineral oils distilled from Boghead coal or other bituminous substance at a
dull red heat, whereby I am enabled. to effect the improvements in gas-
-making above enumerated.
In witness whereof, I, the said George Clark, have hereunto set my.
hand and seal, the Nineteenth day of November, in the year of our
Lord One thousand eight hundred and fifty-six.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
GEO. CLARK. (L.S.)