AN IMPROVED MODE OF MANUFACTURING CEMENT
Year: 1856

page_text: LETTERS PATENT to Henry Young Darracott Scott, of Brompton Barracks,
Chatham, in the County of Kent, Captain in the Royal Engineers, for
the Invention of "AN IMPROVED MODE OF MANUFACTURING CEMENT."
Sealed the 14th October 1856, and dated the 17th April 1856.
PROVISIONAL SPECIFICATION left by the said Henry Young Darracott
Scott, at the Office of the Commissioners of Patents, with his Petition,
on the 17th April 1856.
I, HENRY YOUNG DARRACOTT SCOTT, of Brompton Barracks, Chatham, in
the County of Kent, Captain in the Royal Engineers, do hereby declare the
nature of the said Invention for AN IMPROVED MODE OF MANUFACTURING CEMENT,
to be as follows:-
My Invention consists in subjecting lime (in which term I include every
variety of lime prepared from what are ordinarily called limestones or chalks),
while in a heated state, to the action of sulphurous acid gas, obtained in any

page_text: suitable manner, and mixed or not with other gases accompanying its pro-
duction. By this process I am enabled to obtain a cement (which will set
somewhat after the manner of Portland cement) at a small cost, and of a
uniform color.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Young Darracott Scott in the Great Seal Patent Office
on the 17th October 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
YOUNG DARRACOTT SCOTT, of Brompton Barracks, Chatham, in the County of
Kent, Captain in the Royal Engineers, send greeting.]
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of April, 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 Henry Young Darracott Scott, Her special license that I, the said Henry
Young Darracott Scott, my executors, administrators, and assigns, or such
others as I, the said Henry Young Darracott Scott, my executors, admini-
strators, 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 "AN IMPROVED MODE OF MANUFACTURING CEMENT," upon the con-
dition (amongst others) that I, the said Henry Young Darracott Scott, 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 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 Henry Young Darracott Scott, 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 (that is to say):-
The object of this Invention is to prepare from common quick lime a
substance which will, when ground to powder and made up. with water, set
somewhat after the manner of Portland cement, and gradually attain a very

page_text: great degree of hardness, thus differing essentially in its action from the pre-
paration of lime as ordinarily used..
In carrying out the Invention, I take quick lime, prepared by any of the
ordinary methods, and introduce.it between two perforated and perpendicular
brick walls contained in a kiln, which is also furnished with a fire-place, to
allow of the lime being raised to the required temperature. The roof of the
kiln is arched, to reverberate the heat through the lime, and the distance
between the perforated walls containing it may vary from one to two feet and
upwards, according to the size of the kiln. When the lime is raised to a dull
or cherry red heat, the firing is raked out, and iron pots containing ignited
sulphur are then to be introduced into the kiln, taking care that they are
so placed as to be protected from such a heat as would cause very rapid
cbullition of the sulphur, and allowing no further access of air than will find
its way into the kiln when the flue is shut and the ash-pit and fire door closed.
It is manifest that such a process as this may be carried on in kilns of
various forms, and indeed a more equable distribution of the sulphurous acid
is obtained when the lime is placed on perforated horizontal floors, the above-
described form being used only on account of the greater facility which it
offers for charging and discharging. The effect can also be produced on the
lime while still in the kiln in which it has been burned, but I have found this
method of procedure precarious, from the difficulty apparently of adjusting
the temperature, and of producing regularity of action by the sulphurous acid
throughout the mass. The lime may be used in lumps of the size of a cocoa
nut, more or less, and in a well constructed dry kiln, one pound of sulphur is
a fair allowance for each bushel of lime operated on, but the larger the kiln,
the more the process should be prolonged.
In a laboratory experiment where a rapid current of sulphurous acid can be
passed through a heated glass tube containing the lime, the required change
can be effected in a few minutes. When four or five bushels are operated
upon in a kiln, as above described, I continue the process for two and a half
hours, and with a kiln containing two yards, or thereabouts, I think it
advisable to continue it for six or seven hours, more or less. Limes prepared
from argillaceous limestones or chalks give better results than pure lime, but
of course where the clay is present in sufficient quantity to yield a cement by
ordinary burning simply, nothing would be gained by making use of the above
process also.
Having now described my Invention of "An Improved Mode of Manufac-
turing Cement," I wish it to be understood that under the above in part

page_text: recited Letters Patent, I claim subjecting quick lime, in a heated state, to the
action of sulphurous acid, for the purpose above set forth.
In witness whereof, I, the said Henry Young Darracott Scott, have
hereunto set my hand and seal, the Fifteenth day of October, in the
year of our Lord One thousand eight hundred and fifty-six.
HENRY Y. D. SCOTT. (L.S.)