IMPROVEMENTS IN THE MANUFACTURE OF GAS AND QUICKLIME
Year: 1873

page_text: LETTERS PATENT to the Rev. Granville Hamilton Forbes, of Brough-
ton Rectory, in the County of Northampton, Clerk in Holy Orders,
for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF GAS AND
QUICKLIME."
Sealed the 16th June 1874, and dated the 18th December 1873.
PROVISIONAL SPECIFICATION left by the Revd. Granville Hamilton
Forbes at the Office of the Commissioners of Patents, with his
Petition, on the 18th December 1873.
I, The Rev. GRANVILLE HAMILTON FORBES, of Broughton Rectory,
in the County of Northampton, Clerk in Holy Orders, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE
OF GAS AND QUICKLIME," to be as follows:-
My said Invention relates to a compound of chalk or limestone and
tar, pitch, or similar bituminous substance with or without certain other

page_text: ingredients herein-after specified. The said compound is designed to
serve as a substitute for coal in the manufacture of gas or for making
quicklime.
The said improved compound is made as follows:-I take any desired
quantity of chalk or limestone and combine the same with tar or pitch,
or similar bituminous substance, or a mixture of any two or more of
them. I may also incorporate with the above ingredients a small
quantity of naphtha or petroleum, or other light hydrocarbon oil or
spirit, or vegetable, or animal oil or fat or fatty matter, or a combination
of any two or more of them. The said compound may be formed into
blocks or pieces of any convenient size and shape; it is finally subjected
to distillation in a retort for the manufacture of gas, and the residue left
from the distillation forms quicklime, or the said compound may be
calcined simply for the manufacture of quicklime.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the Revd. Granville Hamilton Forbes in the Great Seal Patent
Office on the 17th June 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, the Rev.
GRANVILLE HAMILTON FORBES, of Broughton Rectory, in the County of
Northampton, Clerk in Holy Orders, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of December, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Revd. 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 Invention
for “IMPROVEMENTS IN THE MANUFACTURE OF GAS AND QUICKLIME," upon the

page_text: condition (amongst others) that I, the said Granville Hamilton Forbes,
my executors or administrators, 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 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 compound of chalk and tar, pitch, or
similar bituminous substance with or without certain other ingredients
herein-after specified. The said compound is designed to serve as a
substitute for coal in the manufacture of gas or for making quicklime.
In
In carrying my said Invention into practise I take any desired
quantity of chalk and combine the same with coal tar or mineral tar, or
mineral pitch, or similar bituminous substance, or with a mixture of any
two or more of them. I effect this combination of the chalk and the
tar or pitch, or similar bituminous substance either by the process of
absorption or by grinding the materials together in a mortar mill. When
I use the process of absorption I proceed in the manner fully described
by me in the Specification of Letters Patent, No. 3110, A.D. 1873.
addition to the tar, pitch, or similar bituminous substance, I sometimes
use a small quantity of naphtha or petroleum, or other light hydrocarbon
oil, or spirit, or vegetable or animal oil or fat or fatty matter, or a com-
bination of any two or more of them. The oil or spirit is mixed with
the tar or pitch or similar bituminous substance before the chalk is
placed in the same. When fat or fatty matter is used it is previously
melted, and is then mixed with the tar or mineral pitch or bituminous
substance. This compound is then heated to boiling point and the chalk
is placed in it, the heat being maintained until sufficient liquid has been
absorbed by the chalk. When pitch is used it is rendered liquid by
hoot

page_text: After the process of distillation is completed the solid residue remain-
ing in the retorts is calcined either by removing the lids of the retorts to
admit the air (the ascension pipes being closed) or by removing the
contents from the retorts and burning them with coke or any other fuel
in a furnace or kiln. Quicklime is then formed.
-I
Instead of using the compound for the manufacture of gas in the
first instance it is sometimes once calcined for the production of quick-
lime. In this case I make use of the following combination only:-
combine chalk with coal-tar, or mineral tar, or mineral pitch, or similar
bituminous substance, and vegetable or mineral oil, or fat, or fatty
matter. I effect this combination by the process of absorbtion as before-
described, and afterwards calcine the compound in a furnace or kiln.
Having thus fully described the nature of my said Invention, and
the manner of performing the same, I wish it understood that I
claim,―
First. The combination of chalk with coal tar or mineral tar, or
mineral pitch, or similar bituminous substance, or a mixture of any two
or more of them by the process of absorption as herein described for the
purpose of manufacturing gas.
Second. The combination of chalk with coal tar or mineral tar, or
mineral pitch, or similar bituminous substance, or a mixture of any two
or more of them, and naphtha or petroleum, or other light hydrocarbon
oil or spirit, or vegetable or animal oil, or fat or fatty matter, or a com-
bination of any two or more of them by the process of absorption, as
herein described for the purpose of manufacturing gas.
Third. The combination of chalk or limestone with coal tar or mineral
tar, or mineral pitch, or similar bituminous substance, or a mixture of
any two or more of them, and naphtha or petroleum, or other light
hydrocarbon oil or spirit, or vegetable or animal oil, or fat or fatter
O matter, or a combination of any two or more of them by the second
process herein specified, namely, by reducing the chalk or limestone to
powder and grinding it with the other specified materials, as herein
described for the purposes of manufacturing gas.
Fourth. The combination of chalk with coal tar or mineral tar, or
5 mineral pitch, or similar bituminous substance, or a mixture of any two
or more of them, and vegetable or animal oil, or fat or fatty matter by

page_text: the process of absorption, as herein described for the purpose of manu-
facturing quicklime.
In witness whereof, I, the said Granville Hamilton Forbes, have
hereunto set my hand and seal, this Sixteenth day of June, in
the year of our Lord One thousand eight hundred and seventy-
four.
Witness,
HENRY SHAW,
GRANVILLE HAMILTON FORBES. (L.s.)
Schoolmaster,
Broughton,
Northamptonshire.