A NEW OR IMPROVED COMPOUND FOR USE AS FUEL, OR FOR THE MANUFACTURE OF GAS FOR HEATING AND ILLUMINATING PURPOSES, CAPABLE ALSO OF BEING USED IN THE PRODUCTION OF A MATERIAL SUITABLE FOR THE PURIFICATION OF GAS
Year: 1874

page_text: LETTERS PATENT to the Revd. Granville Hamilton Forbes, Clerk in
Holy Orders, Rector of Brougliton, in the County of Northampton, for
the Invention of "A NEW OR IMPROVED COMPOUND FOR USE AS FUEL, OR
FOR THE MANUFACTURE OF GAS FOR HEATING AND ILLUMINATING PURPOSES,
CAPABLE ALSO OF BEING USED IN THE PRODUCTION OF A MATERIAL SUITABLE FOR
THE PURIFICATION OF GAS."
Scaled the 28th April 1874, and dated the 4th March 1874.
PROVISIONAL SPECIFICATION left by the said Rev. Granville
Hamilton Forbes at the Office of the Commissioners of Patents,
with his Petition, on the 4th March 1874.
I, Revd. GRANVILLE HAMILTON FORBES, Clerk in Holy Orders, Rector
of Broughton, in the County of Northampton, do hereby declare the
nature of the said Invention for "A NEW OR IMPROVED COMPOUND FOR USE AS
FUEL, OR FOR THE MANUFACTURE OF GAS FOR HEATING AND ILLUMINATING PURPOSES,
CAPABLE ALSO OF BEING USED IN THE PRODUCTION OF A MATERIAL SUITABLE FOR THE
PURIFICATION OF GAS," to be as follows:-
.
M.. said Invention refers to a combination of chalk or the refuse

page_text: (chloride of sodium) and saltpetre (nitrate of potassa) or nitrate of soda
or its equivalent; or (instead of the above mixture) with common soda
(carbonate of soda) or equivalent, with or without tar or similar
bituminous substance. The compound thus formed is used as a fuel
together with coal or any other fuel; or it may be used for the manu-
facture of gas for heating and illuminating purposes together with coal
or its equivalent; or it may be burnt, and the residuum of the com-
bustion may be used for purifying gas.
In carrying out this Invention I break the chalk into pieces of a
suitable size and place them in water, in which common salt and salt-
petre or nitrate of soda or its equivalent have been dissolved. I allow
the chalk to remain in this solution until it has absorbed sufficient of
the liquid, I then remove the chalk and dry it, when it is fit for use for
any of the purposes above specified.
Instead of a solution of common salt and saltpetre or nitrate of soda
or its equivalent I sometimes use a solution of common soda. The
proportions of the above-named salts will vary considerably. I may use
a saturated solution of common soda or a solution of any lesser degree
of strength. In like manner I may use a solution of the first-named
salts of any degree of strength, but in this solution the proportion which
the saltpetre or nitrate of soda or its equivalent bears to the common
salt will be not more than ten per cent.
I may sometimes soak the chalk (after treating it in the manner above
described) in tar or similar bituminous substance.
Instead of chalk I sometimes use refuse or foul lime. I treat the
lumps or pieces of refuse lime in the same manner as the chalk. When
the refuse lime is in powder I mix it with either of the solutions above
-specified by any convenient means, and afterwards dry the compound
thus formed. Tar or its equivalent may be added.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the Rev. Granville Hamilton Forbes in the Great Seal
Patent Office on the 3rd September 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, the Revd.
GRANVILLE HAMILTON FORBES, Clerk in Holy Orders, Rector of
Broughton, in the County of Northampton, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourth day of March, in the year of
our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,.
give and grant unto me, the said Granville Hamilton Forbes, Her special
licence, that I, the said Granville Hamilton Forbes, my executors,
administrators, and assigns, or such others as I, the said Granville
Hamilton Forbes, 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 In-
vention for "A NEW OR IMPROVED COMPOUND FOR USE AS FUEL OR FOR THE
MANUFACTURE OF GAS FOR HEATING AND ILLUMINATING PURPOSES, CAPABLE ALSO OF
BEING USED IN THE PRODUCTION OF A MATERIAL SUITABLE FOR THE PURIFICATION OF
GAS," upon the condition (amongst others) that I, the said. Granvillo
Hamilton Forbes, my executors or administrators, by an instrument - in
writing under my, or their, or one of their hands and scals, 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 immediately after the date of the said Letters Patent.'
NOW KNOW YE, that I, the said Granville Hamilton Forbes, 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:-
My-said Invention relates to a combination of chalk or the refuse
lime of gasworks with a saline mixturo composed of common salt
(chloride of sodium) and saltpetre (nitrate of potash) or nitrate of soda;
or (instead of the above mixture of salts) with common soda (carbonate

page_text: of soda) or carbonate of potash, the compound so produced being used
with or without a certain proportion of tar or some similar bituminous
substance. The compound thus formed is used as a fuel together with
coal or any other fuel; or it is used for the manufacture of gas for
heating and illuminating purposes together with coal or bituminous schist
or schale or other similar bituminous substance, or it is burnt, and the
residuum of the combustion used for purifying gas.
In carrying out this Invention I break the chalk into pieces of a
suitable size and place them in a solution of common salt and saltpetre
or nitrate of soda or alkaline carbonate, as specified above. I allow the
chalk to remain in this solution until it has absorbed sufficient of the
saline liquid. I then remove the chalk and dry it, either by exposure to
the sun and air or by artificial heat; when dry it is fit for use as
fuel or for burning for the production of a lime suitable for use in the
purification of gas.
When the compound is intended for the manufacture of gas I also
combine tar or similar bituminous substance with it, as herein-after
more particularly described. The proportions of the above-named salts
will vary considerably. .I sometimes use a saturated solution of
carbonate of soda; sometimes I use a solution of a lesser degree of
strength. In like manner I use a solution of the first-named salts of
any degree of strength, but in this solution the proportion which the
nitrate of potash bears to the common salt will be not more than ten
per cent.
When nitrate of soda is used instead of nitrate of potash I employ
such proportions of the former as will give a chemical equivalent for
the latter, for example, for ten parts of nitrate of potash I use nine and
one-tenth (9.1) parts of nitrate of soda, and so on in like manner.
When carbonate of potash is used instead of carbonate of soda for
ten parts of the latter I employ eleven and four-tenths (11·4) parts of
the former.
When the compound is designed for the manufacture of gas in those
cases where common salt and saltpetre are employed I prefer to use a
saturated solution of common salt with ten per cent. of nitrate of potash
(by weight). When carbonate of soda (or carbonate of potash) is
employed I prefer to use a saturated solution diluted with about an
equal weight of water, but I do not restrict myself to use always these

page_text: exact proportions. When however the compound is designed for fuel
or for the production of a lime suitable for the purification of gas, in
those cases where common salt and nitrate of potash (or nitrate of soda).
are employed, I prefer to use from about five to ten per cent. of nitrate.
of potash or the equivalent proportion of nitrate of soda. In those cases.
where carbonate of soda (or carbonate of potash) is employed I some
times use a saturated solution of the former (or the equivalent of the.
latter).
I sometimes soak the chalk (after treating it in the manner above
described) in coal tar or mineral tar or some bituminous substance,
which is either naturally liquid or which can be rendered liquid by heat.
For this purpose I place the prepared chalk in the tar or other suitablo
bituminous substance and allow it to remain until it is thoroughly
penetrated by the liquid. I then remove the saturated chalk and allow
it to dry by exposure to the air. It is then fit for use, either as fuel or
for mixing with coal or bituminous matter of the proper kind for the
manufacture of gas or for burning for the production of a lime suitable
for the purification of gas.
When the compound is designed for fuel, instead of chalk I some-
times use the refuse or "foul" lime of gasworks or of soap and chemical
works. I treat the lumps or pieces of foul lime in the manner above
described, that is to say, I place them in the saline solution already
described and allow them to remain until they are saturated by the
liquid. They are afterwards removed and dried, either with or without
artificial heat, and they are then fit for use as fuel.
Sometimes after saturating the lumps or pieces of refuse or foul lime
with the solution of the salts above specified and subsequently drying
them I soak them in coal tar, or mineral tar, or some suitable bituminous
substance in the manner above described in reference to the chalk.
When the refuse or foul lime is in a pulverized state I mix it with
either of the saline solutions above specified, either by hand or by any
convenient machine for grinding or mixing, such as a mortar mill or by
any other convenient means. It is then pressed or moulded into balls
or blocks. It is afterwards dried. It will harden and dry to some
extent by exposure to the sun and air, but I prefer to dry it by a
moderate degree of artificial heat. It is then fit for use. I sometimes
also mix with it coal tar, or mineral tar, or other suitable bituminous

page_text: substance. The foul lime is first mixed with the solution of salts, then
dried (by a moderate degree of artificial heat) in a loose state and after-
wards mixed with the tar or other suitable bituminous substance by.
hand or by machinery. It is then formed into balls or pieces of a con-
venient size and shape. For mixing and agglomerating the tar (or other
bituminous substance) with the other materials. I prefer to use one of
Anderson's Patent breeze and tar fuel machines, but any other suitable.
machine may be used.
When the chalk, prepared as above described, is used for the manu-
facture of gas I break it into pieces about the size of a hen's egg and
use it with coal or other suitable bituminous material (as specified) in
the retorts usually employed for making coal gas. The pieces of pre-
pared chalk and coal or other material should be well intermingled in
the retorts. The temperature of the retorts should be not lower than
that which is usual in ordinary gas making, and the purification of the
gas is carried on in the usual manner. The proportions that I prefer.
to use are from one to two parts by weight of the compound to two.
parts of coal or other bituminous substance proper for my purpose,.
in proportions according to the richness of the same as a gas yielding
material.
After the process of distillation in the retorts is completed their
contents may be used in the furnaces for heating the same and the
calcination of the chalk thus completed. The prepared chalk and the
coke will be found to have great heating power as a fuel. The quick-
lime thus produced may be used in the purification of gás. For the
purposes of this Invention I use cither common culinary salt or rock
salt.
When the prepared compound is used simply as a fuel it is mixed in
burning with coal or coke or cinders.
When the compound is designed for the production of a lime suitable
for the purification of gas I employ chalk in every case. The compound
is calcined either in a kiln or furnace or stove, and the calcined material
is slaked and used in the purifiers in the usual way.
Having thus fully described my said Invention and the manner of
performing the same, I wish it to be understood that I claim,-
First. The combination of common salt (chloride of sodium) and
saltpetre (nitrate of potassa) or nitrate of soda or carbonate of soda or

page_text: carbonate of potash with chalk or the foul or refuse lime of gasworks,
and with or without tar or other suitable bituminous substance for use
as fuel, as herein described.
Second. The combination of common salt and saltpetre or nitrate of
soda or carbonate of soda or carbonate of potash with chalk and tar or
other suitable bituminous matter for use in the manufacture of gas, in
the manner hercin described.
Third. The combination of common salt and saltpetre or nitrate of
soda or carbonate of soda or carbonate of potash with chalk, and with or
without tar or similar bituminous substance for the purpose of making a
compound to be calcined for the production of a material suitable for the
purification of gas, as herein described.
In witness whereof, I, the said Granville Hamilton Forbes, have
hereunto set my hand and seal, this First day of September,
in the year of our Lord One thousand eight hundred and seventy-
four.
GRANVILLE HAMILTON FORBES. (L.S.)
Witness,
'
JOSEPH BLACK,
Coast Guardsman,
Hunstanton,
Norfolk.