CERTAIN IMPROVE- MENTS IN THE MANUFACTURE OF A COMPOSITION APPLICABLE AS A CEMENT OB PLASTER, AND TO OTHER PURPOSES
Year: 1856

page_text: LETTERS PATENT to Alfred Francis, of Encomb Terrace, Wandsworth
Road, Cement Manufacturer, for the Invention of "CERTAIN IMPROVE-
MENTS IN THE MANUFACTURE OF A COMPOSITION APPLICABLE AS A CEMENT OB
PLASTER, AND TO OTHER PURPOSES."
Sealed the 6th May 1856, and dated the 1st March 1856.
PROVISIONAL SPECIFICATION left by the said Alfred Francis at the
Office of the Commissioners of Patents, with his Petition, on the
1st March 1856.
I, ALFRED FRANCIS, of Encomb Terrace, Wandsworth Road, Cement
Manufacturer, do hereby declare the nature of the said Invention for
"CERTAIN IMPROVEMENTS IN THE MANUFACTURE OF A COMPOSITION APPLICABLE AS
A CEMENT OR PLASTER, AND TO OTHER PURPOSES," to be as follows:-
The Invention relates to the combination of borax with gypsum (sulphate of
lime) & other calcareous substances, and I would here state that I am aware it
has heretofore been proposed to combine borax with gypsum by first forming.
a solution of the borax, with which was mixed a solution of cream of tartar,
and then placing therein the gypsum, which had been by heat deprived of the
water of crystallization, and allowing it to remain there a considerable time
for the absorption of such liquid, when gypsum thus treated was heated to a
red heat, and then reduced to powder, but such process is found laborious and

page_text: expensive. And my improvements consist in first subjecting the gypsum or
other calcareous substance to heat to calcine it, and afterwards mixing there-
with dry borax, ground or otherwise reduced to a granulated or powdered
state without the aid of heat, or cream of tartar, or other such acid, by which
a considerable economy of manufacture is obtained with the production of
a superior composition applicable to various purposes, such as for which
plater of paris has been used, but which is capable of receiving hard
enamelled surfaces.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alfred Francis in the Great Seal Patent Office on the
1st September 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
FRANCIS, of Encomb Terrace, Wandsworth Road, Cement Manufacturer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the First day of March, 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.
Alfred Francis, Her special licence that I, the said Alfred Francis, my
executors, administrators, and assigns, or such others as I, the said Alfred
Francis, 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 "CERTAIN IMPROVEMENTS IN THE
MANUFACTURE OF A COMPOSITION APPLICABLE AS A CEMENT OR PLASTER, AND TO
OTHER PURPOSES," upon the condition (amongst others) that I, the said
Alfred Francis, 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.

page_text: NOW KNOW YE, that I, the said Alfred Francis, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
The Invention relates to a combination of borax with gypsum (sulphate
of lime), and other calcareous substances for the production of a composition
to be used as a cement or plaster. And I would here state that I am aware
it has heretofore been proposed to combine borax with gypsum to produce
cement or plaster, but in such case a solution of the borax was first obtained,
with which was combined a solution of cream of tartar, and the gypsum
(deprived by heat of the water of crystallization), was then placed in the
compound solution, in order to its combining therewith by absorption, for
which purpose it was necessary that the gypsum be allowed to remain a
considerable time in such solution. The gypsum thus treated was then
subjected to a red heat, and afterwards reduced to powder by suitable means.
But such process has been found laborious and expensive, and my improve-
ments consist in combining the borax with the gypsum in a dry state, for
which purpose I first subject the gypsum or other calcareous substance to
heat to calcine it, and then mixing therewith the dry borax, ground or other-
wise reduced to a granulated or powdered state without the aid of heat thereto,
or of the cream of tartar or other such acid, whereby I effect considerable
economy in manufacture, and am enabled to produce a superior composition
applicable to various purposes, such as for which plaster of paris has hereto-
fore been employed, but much more durable and better capable of receiving a
hard and enamelled surface.
I find it important to reduce the dry borax to a very fine powder, and then
to sift it by means of a very fine sieve before mixing it, and in this finely powdered
state I mix it with calcined gypsum or other calcareous substance, reduced by
grinding or otherwise to a fine powder, and I effect the mixing by means of a
machine, such as ordinarily used in mixing other compositions for cement, or
by other suitable means, by which to insure the matters being well mixed.
The proportions of the compositions which I have found to answer well are
40 to 50 lbs. of the dry borax to 20 cwt. of calcined gypsum, but these pro-
portions may be varied.
Having thus described the nature of my said Invention, and the means
which I adopt in carrying the same into effect, I would have it understood
that I do not claim generally the combination of borax with gypsum or such
like calcareous substance for the manufacture of cement or plaster. But what

page_text: I do claim is, the combination of dry borax with calcined gypsum or other
calcarcous substance, as and for the purpose, explained.
In witness whereof, I, the said Alfred Francis, have hereunto set my
hand and seal, this Thirtieth day of. August, in the year of our
'Lord One thousand eight hundred and fifty-six:
ALFRED FRANCIS. (L.S.)
Witness,
R. WOODWARD, Sol",
28, Great James Street, Bedford Row.