IMPROVEMENTS IN THE MANUFACTURE OF CEMENT AND MORTAR
Year: 1870

page_text: LETTERS PATENT to Henry Young Darracott Scott, of Ealing, in
66
the County of Middlesex, Lieutenant-Colonel Royal Engineers, for
the Invention of IMPROVEMENTS IN THE MANUFACTURE OF CEMENT
AND MORTAR."
PROVISIONAL SPECIFICATION left by the said Henry Young Darracott
Scott at the Office of the Commissioners of Patents, with his Petition,
on the 21st December 1870.
I, HENRY YOUNG DARRACOTT SCOTT, of Ealing, in the County of
Middlesex, Lieutenant-Colonel Royal Engineers, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
CEMENT AND MORTAR," to be as follows:-
These improvements have reference to processes for which Letters
Patent, dated April 26th, 1870, and Numbered 1204 and 1205, re-
spectively were granted to me. The first or selenitic mortar process
relates to an improved method of preparing mortar by controlling the
slacking action of water upon the quicklime by means of a thin slip of
sulphate of lime or other equivalent sulphate or compound capable of
yielding sulphuric acid to the limo.

page_text: According to my present Invention I make use of calcarcous shales
or marls which are for the most part at present reburied in quarrying
for limestone or chalk. In these shales or marls whilst the quantity of
carbonate of lime is insufficient (without further preparation or admix-
ture) to enable the calcined material to be used as a lime or cement, it
is yet sufficient, under the action of heat to bring the silex contained
in the clay into that state in which it will gelatinize when treated
with hydrochloric acid.
In carrying out my present improvements for my selenitic mortar
process which have special reference to the purer descriptions of lime,
I proceed to make a selenitic slip in the way I have already described,
and I add thereto of the calcined and ground shale about three times
the bulk of the quicklime employed, I then introduce into this compound
such proportions of sand as the particular application of the mortar may
render advisable. The second or selenitic cement process deals with the
preparation of cement by the calcination of compounds of chalk or
quicklime and clay to which a small percentage of sulphate of lime or
other soluble sulphate has been added.
In applying my present improvements to this process I proceed
somewhat differently. In this case I grind together 20 to 30 parts of
chalk or lime and of the above-mentioned calcarcous shales from 60
to 80 parts, and of sulphate of lime or other equivalent sulphate about
one part. These substances I triturate and grind with water in the
manner I have already set forth, and reduce them to a homogeneous
paste, and I proceed with the manufacture as before described. In either
case I sometimes make use of a small quantity of alkaline silicate to
increase the hydraulic action of the mortar. This silicate I introduce
along with the materials in the grinding mill.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
YOUNG DARRACOTT SCOTT, of Ealing, in the County of Middlesex,
Lieutenant-Colonel Royal Engineers, send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of December, in the
year of our Lord One thousand eight hundred and seventy, in the thirty-.
fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Henry Young Darracott Scott, Her
special licence that I, the said Henry Young Darracott Scott, my exe-
cutors, administrators, and assigns, or such others as I, the said Henry
Young Darracott Scott, 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 CEMENT AND MORTAR,"
upon the condition (amongst others) that I, the said Henry Young
Darracott Scott, 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 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):-
These improvements have reference to processes for which Letters
Patent, dated April Twenty-sixth, One thousand eight hundred and
seventy, and Numbered 1204 and 1205 respectively were granted to
me. The first or selenitic mortar process relates to an improved method.
of preparing mortar by controlling the slaking action of water upon.
the quicklime by means of a thin slip of sulphate of lime or other
equivalent sulphate or compound capable of yielding sulphuric acid to
the lime.
'
According to my present Invention I make use of calcareous shales
These shales
or marls for the manufacture of cement and mortar.
or marls are for the most part at present reburied in quarrying for
limestone or chalk after the latter have been removed from the quarry.
In these shales or marls whilst the quantity of carbonate of lime is
insufficient (without further preparation or admixture) to enable the

page_text: calcined material to be used as a lime or cement it is yet sufficient
(under the action of heat) to bring the silex contained in the clay into
that state in which it will gelatinize when treated with hydrochloric
acid.
In carrying out my present improvements for making selenitic mortar
I burn these shales or marls either in heaps or in kilns and reduce them
to a powder. Having the calcined marls thus prepared I then proceed
to make a selenitic slip in the following manner:-Into about half a
pail of water I introduce a small quantity of plaster of Paris or some
other equivalent sulphate, equal in bulk to about one-twentieth part of
the lime intended to be employed or an equivalent quantity of sulphuric
acid, and after well stirring these ingredients I throw them into the
pan of an ordinary mortar mill. To this mixture I add from two to
four pails of water, according to the size of the mill, and then gradually
introduce the lime which should be of the kind usually known as a pure
or fat lime; I then grind the whole for three or four minutes to the con-
sistency of a creamy paste; I add thereto the following proportions of
the calcined and ground shale above mentioned. If the shale contains
forty per cent. of lime I use one part of prepared shale to two parts
of the lime employed in making the selenitic slip. If the shale contains
fifty per cent. of lime I use one part of the prepared shale to one and
a half parts of the lime employed, and if the shale contains sixty per
cent. of lime I use one part of shale to one part of the lime employed.
But I may in certain cases use from three to four parts of the shale
with very good effect, and I have obtained very good results from using
three parts of shale and three parts of sand to one of lime, which is the
proportion I prefer for common mortar. Having intimately mixed the
lime and calcined shale or marl, I then introduce into this compound
such proportions of sand as the particular application of the mortar may
render advisable. The second or selenitic cement process deals with the
preparation of cement by the calcination of compounds of chalk or
quicklime and clay to which a small percentage of sulphate of lime or
other soluble sulphate has been added.
In applying my present improvements to this process I proceed some-
what differently. In this case in using chalk I grind together twenty
parts of chalk, and of shales rich in lime eighty parts, or if the shale
contain less lime I use from thirty to forty parts of chalk and of sulphate
of lime one part. In employing quicklime I may use about fifteen

page_text: parts of lime with rich shales and thirty-five parts with poor shales, and
one part of sulphate of lime as before. These substances I triturate and
grind with water in the manner I have already set forth in the Specifi-
cation of my Patent dated April Twenty-sixth, One thousand eight
hundred and seventy, No. 1204, and I reduce them to a homogeneous
paste, and I proceed with the manufacture of the cement as described
in my former Patent for making cement. When I make use of the
mortar, I sometimes employ a small quantity of alkaline silicate to
increase the hydraulic action of the mortar. This silicate I introduce
along with the material in the grinding, mill.
Having now described my Invention of " Improvements in the
Manufacture of Cement and Mortar," and having explained the means
whereby I propose to carry the same into effect, I wish it to be under-
stood that I claim as the Invention secured to me by Letters Patent
as aforesaid,
First. The use of the calcareous marls or shales herein-before referred
to in conjunction with pure or fat limes for the preparation of mortar
and plaster as herein set forth.
Second. The manufacture of cements from the marls or shales above
referred to in conjunction with quicklime or chalk as herein set forth.
Third. I claim the use of the silicates of potash and soda in con-
junction with the selenitic process in the preparation of mortar and
plaster as herein set forth.
In witness whereof, I, the said Henry Young Darracott Scott,
have hereunto set my hand and seal, the Twenty-first day of
June, in the year of our Lord One thousand eight hundred and
seventy-one.