IMPROVEMENTS IN COMPOUNDS DESIGNED FOR THE MANU- FACTURE OF CEMENTS, PLASTER, OR ARTIFICIAL STONE; CAPABLE ALSO OF BEING USED FOR ARTIFICIAL Fuel
Year: 1874

page_text: LETTERS PATENT to Granville Hamilton Forbes, Clerk in Holy Orders,
Rector of Broughton, in the County of Northampton, for the
Invention of "IMPROVEMENTS IN COMPOUNDS DESIGNED FOR THE MANU-
FACTURE OF CEMENTS, PLASTER, OR ARTIFICIAL STONE; CAPABLE ALSO OF
BEING USED FOR ARTIFICIAL Fuel.”
Sealed the 5th June 1874; and dated the 2nd January 1874.
PROVISIONAL SPECIFICATION left by the said Granville Hamilton
Forbes at the Office of the Commissioners of Patents, with his
Petition, on the 2nd January 1874.
I, 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 "IMPROVEMENTS IN COMPOUNDS DESIGNED FOR THE
MANUFACTURE OF CEMENTS, PLASTER, OR ARTIFICIAL STONE; CAPABLE ALSO OF
BEING USED FOR ARTIFICIAL FUEL," to be as follows:-
.
My said Invention is a further developement of my former Inventions
for which Letters Patent, Numbers 1816 and 1832, A.D. 1873, were
granted to me..

page_text: According to my aforesaid Inventions I combined the foul or refuse
lime of gas works with coal tar or the tar produced in the distillation of
a mixture of coal and bitumen, and as described in the Specification of
Letters Patent, Number 1832, with chalk or limestone also.
According to my present Invention I combine the foul lime of gas
works or its equivalent with coke, with or without chalk or limestone,
with or without tar or pitch or similar bituminous substance, or a
combination of any two or more of such substances, and with or without
petroleum or other hydrocarbon oil or spirit, or a mixiure of any two or
more of them.
In practising my said Invention I mix the materials either by hand or
by suitable machinery. The compound is then burnt either in a grate,
or stove, or furnace, or kiln, and when sufficiently burnt is reduced to
powder for use, as cement or plaster or artificial stone.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Granville Hamilton Forbes in the Great Seal
Patent Office on the 2nd July 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, 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 Second day of January, in the
year of our Lord One thousand eight hundred and seventy-four, in
the thirty-seventh year of Her reigu, 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
Invention for "IMPROVEMENTS IN COMPOUNDS DESIGNED FOR THE MANUFACTURE

page_text: OF CEMENTS, PLASTER, OR ARTIFICIAL STONE; CAPABLE ALSO OF BEING USED FOR
ARTIFICIAL FUEL," upon the condition (amongst others) that I, the said
Granville Hamilton Forbes, my executors or administrators, by an instru-
ment 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 is a further development of my former Inventions
for which Letters Patent, Nos. 1816 and 1832, in the year of our Lord
One thousand eight hundred and seventy-three, were granted to me.
According to my aforesaid Inventions I combined the foul or refuse
lime of gas works with coal tar or the tar produced in the distillation of
a mixture of coal and bitumen, and as described in the Specification of
Letters Patent, No. 1832, with chalk or limestone also.
of
According to my present Invention I combine the foul lime of gas
works with coke, with or without chalk or limestone, for the purpose
forming a compound or compounds suitable for the manufacture of
cement, plaster, or artificial stone; capable also of being used for
artificial fuel.
The compound or compounds produced by my Invention may be used
simply for the purpose of manufacturing cement, plaster, or artificial
stone, or may be burnt as artificial fuel together with coal or any other
fuel, and the residue of the combustion of the said compound or com-
pounds may be used as cement or plaster or for making artificial stone.
In carrying this my said Invention into effect I proceed as follows :-
I grind the foul lime of gas works together with coke and chalk or
limestone in a mortar mill with sufficient water to mix the materials
intimately. When sufficiently mixed the compound is taken from the
mill and left to dry, or is dried by artificial heat in an oven or by any
other convenient means.. It is then burnt, together with coal of

page_text: other fuel in a grate or furnace or kiln. When sufficiently burnt it is
ground to a very fine powder by hand or by machinery. It is then ready
for use as cement or plaster or for making artificial stone. When used
for any of these purposes it is mixed with water. The coke which I
employ in this process is gas coke from the distillation of the Derbyshire
deep main coal (Riddings' colliery) or from any other coal producing
coke of a similar or nearly similar nature, or any other coke the ash of
which mainly consists of silicate of lime, alumina, and oxide of iron, or
of silicate of alumina, or of silicate of alumina, lime, and oxide of iron,
or of silicate of alumina and oxide of iron. The presence of nitrate of
cobalt or any equivalent is immaterial. The refuse or small coke of gas
works commonly termed coke breeze is better suited to the purposes of
Invention than that portion of the coke which is usually sold for
fuel, and accordingly I use the former in preference. I prepare it for
use in the following manner :-I first separate the coke dust from the
breeze by finely screeing or sifting the material. I then place the
breeze in water, when the lighter portion of it will float and the heavier
portion will sink. I reject the latter and make use only of that which
does not sink at once when it is placed in the water.
my
One advantage of using the coke breeze is that the separation of the
suitable from the unsuitable portion of it is more easily effected than is
the case with the larger coke. I do not however reject the use of the
larger coke for the purposes of my Invention. When I employ it I
break or crush it into small pieces. I subject these to the same test,
rejecting those which sink at once in water, and using only the lighter
portions. The dust of the coke breeze is prepared for use by being again
sifted or screened more finely than before. When used it should be used
separately from the other coke.
The proportions of the foul lime and the other ingredients used will
vary according to the object for which the compound is designed.
When the compound is designed for the manufacture of cements
instead of chalk I use a good hydraulic limestone. The proportion in
this case will be about as follows:-Three parts of foul lime, two parts
of hydraulic limestone, from one to two and a half parts of coke, pre-
pared as above. For this purpose I employ coke, the ash of which consists
of silicate of alumina or silicate of lime and alumina, with only a small
proportion of oxide of iron. When I use the coke of the Derbyshire

page_text: coal before specified or any other coke of a similar or nearly similar
nature, I employ only the light portion of the breeze, prepared as before
described.
When the compound is designed for the manufacture of plaster or
artificial stone I use the following ingredients and proportions:-Two
parts of foul lime, one part of chalk, and one and a half parts of the
light portion of coke breeze; but I do not tie myself to use always these
exact proportions. I do not however at any time employ a larger pro-
portion of coke than that last specified.
When the compound is designed for the manufacture of artificial
stone only I sometimes employ the following mixture:-Two parts of
foul lime and one part of the light portion of coke breeze. Instead of
this I sometimes use the following:-Two parts of foul lime with one
part of the dust of the breeze sifted through a very fine hair sieve; or
two parts of foul lime, one part of limestone of the blue lias formation,
and from one to one and a half parts of the light portion of breeze, or
the same proportion of the dust, sifted as before. I give these propor-
tions as examples, but do not tie myself to use always the exact
proportions here given.
In all the above cases the proportions are by weight.
The proportion of foul lime used in all the above specified compounds
may be varied within certain limits. It is necessary to reserve to myself
this right in consequence of the variable quality of the foul lime. The
proportions of foul lime given above are intended to yield in the calcined
compound from about ten to about twenty per cent. of sulphate of lime.
For this reason I do not employ for the purposes of my Invention any
foul lime which contains an unusually low per centage of sulphur or
compounds of sulphur. When the foul lime used does not contain
enough sulphur or sulphur compounds I increase the proportion of it.
accordingly, reducing the proportion of chalk used with it in the same
ratio.
In calcining the compounds care must be taken not to overburn
them.
Having now particularly described and ascertained the nature and
object of my Invention, and the manner in which the same is to be
performed or put in practice, I wish it understood that I claim,-

page_text: First. The combination of the herein specified coke with the foul lime
of gas works and the herein specified limestone for the purpose of
manufacturing cements, as herein described.
Second. The combination of the herein specified coke with the afore-
said foul lime and chalk for the purpose of manufacturing plaster or
artificial stone, as herein described.
Third. The combination of the herein specified coke with the aforesaid
foul lime, with or without the herein specified limestone, for the purpose.
of manufacturing artificial stone, as herein described.
In witness whereof, I, the said Granville Hamilton Forbes, have
hereunto set my hand and seal, this First day of July, in the
year of our Lord One thousand eight hundred and seventy-four.
GRANVILLE HAMILTON FORBES. (L.S.)
Witness,
HENRY SHAW,
Schoolmaster,
Broughton,
Northamptonshire.