A certain Process or Processes, Method or Methods of combining various Materials so as to form Stuccoės, Plasters, or Cements, and for the Manufacture of Artificial Stones, Marble, and other like Substances used in Buildings, Decorations, or other similar Purposes
Year: 1840

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
FREEN MARTIN, of Derby, in the County of Derby, Gentleman, send greeting.
WHEREAS His late Majesty William the Fourth did, by His Letters
Patent, of date the Eighth day of October, One thousand eight hundred and
thirty-four, grant unto me, my exors, admors, and assigns, the sole and ex-
clusive privilege, for the term of fourteen years thereafter, of making, using,
exercising, and vending, within that part of the United Kingdom of Great
Britain and Ireland called England, His Dominion of Wales, and Town of
Berwick-upon-Tweed, "A certain Process or Processes, Method or Methods
of combining various Materials so as to form Stuccoės, Plasters, or Cements,
and for the Manufacture of Artificial Stones, Marble, and other like Substances
used in Buildings, Decorations, or other similar Purposes," of which process
or processes, method or methods, and others, a particular Specification was
directed to be and was inrolled in the High Court of Chancery within six
months after the date of the said Letters Patent, as in and by the same,
reference being thereunto had, will more fully and large appear.
And whereas Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Second day of June, in the third year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said Richard
Freen Martin, my exors, admors, and assigns, Her especial licence, full power,
sole privilege and authority that I, the said Richard Freen Martin, my
exors, adñiors, and assigns, and such others as I, the said Richard Freen

page_text: Martin, my exors, adñiors, or assigns, should at any time agree with, and
no others, should and lawfully might make, use, exercise, and vend, within
that part of Her Majesty's United Kingdom of Great Britain and Ireland
called England, Her Dominion of Wales, Town of Berwick-upon-Tweed, or
in any of Iler said Majesty's Colonies and Plantations abroad, my Invention
of "CERTAIN IMPROVEMENTS IN THE MANUFACTURE OF CERTAIN DESCRIPTIONS OP
CEMENT;" in which said Letters Patent is contained a proviso that I, the said
Richard Freen Martin, shall cause a particular description of the nature of
my said Invention, and in what manner the same is to be performed, to be
inrolled in Her said Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the said in part recited
Letters Patent, as in and by the same, reference being thereunto had, will
more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso contained
in the said last recited Letters Patents, I, the said Richard Freen Martin,
do hereby declare that the improvements for which the same have been
granted relate more particularly to those descriptions of cement for which
the said Letters Patent of the Eighth day of October, One thousand eight
hundred and thirty-four were granted, but are also applicable to other
cements, as herein-after explained; and I declare that the following is a
particular description of the said improvements and of the manner in which
they are to be performed, that is to say:-Whereas by the Specification of
the first herein-before recited Letters Patent, I directed, in order to the
production of certain hard cements, that gypsum, either in its natural stato
or in its manufactured state of plaster of Paris, or limestone, or chalk,
or lime, should be first reduced into a state of powder and then mixed with
a solution of any strong alkali neutralized by means of an acid (preferring for
the purpose American pearlash and sulphuric acid, but claiming all such
other alkalis and acids as would answer the purpose,) and that water should be
added to the mixture till it attained a consistence or state suitable for moulding
into cakes or bricks or other forms, which were to be afterwards dried and
burnt in manner therein described. And whereas I also stated that the
solution of the alkali might be employed without the addition of any acid, or
an acid solution without mixture with any alkaline solution, but that cements
so made would not be so good as those made by the combination of the alkali
and acid. Now I have since discovered that the said processes may be
facilitated and shortened as well as the cost of them reduced by the means
and in manner following: :-
First, instead of employing the alkalis and acids in a state of solution and

page_text: afterwards adding water to the intermixed materials, I use the alkalis and
acids in a solid state, and do not use water at all in any stage of my operations,
excepting only such water as the materials themselves may contain, and I either
use the alkalis and acids in such solid state, previously combined in proper
proportions, or I add them separately in the same proportions to the gypsum,
or limestone, or chalk, or lime.
And, second, I dispense in a certain case with the alkaline addition altogether,
and in a certain other case with the addition of both the alkali and acid, and
depend on the quantities of these ingredients incorporated in the substances
themselves which form the basis of the cements. And with reference to the
first of the said inprovements, I declare that in order to obtain a solid com-
pound containing the due proportions of alkali and acid, I pursue the following
process: I dissolvo a quantity of pearlash in water and add as much sul-
phuric acid as is requisite to neutralize the same or can be neutralized by
it, and afterwards by boiling I evaporate this solution to dryness, when a
residuum is left which is the compound required. When it is desired to add
the alkali and acid separately and in a solid state to the gypsum, or limestone,
or chalk, or lime, I obtain the alkaline constituent by using any of the known
alkalis in an undissolved state (preferring pearlash), or where cements of
superior density are required using a portion some of the alkaline earths (as
barytes for instance), and I obtain the acid constituent by employing either
sulphur or sulphuric acid in a state of solid combination with other substances
(as pyrites and mineral sulphates, for example), or sulphur by itself, or some
solid compound containing both an acid and an alkali, as alum or some mixture
of two or more of the said or similar ingredients. And in proportioning
the said constituents, the one to the other, it is necessary to observe this
general rule, that the acid which is added or which may result from the com-
bination of the said materials, or any of them, shall be only just sufficient to
neutralize or be neutralized by the alkali with which it is brought in com-
bination, so that where any of the substances employed contain both an acid and
an alkali, such as alum, the quantity of the superadded alkali must be reduced
in proportion to the quantity of alkali incorporated in such acid alkaline sub-
stance itself. And having provided from the sources and in manner before
described, supplies the alkaline and acid matters in a solid state, I proceed as
follows: Where gypsum in its natural state or limestone or chalk is to bo
used as the basis of the cement, I take any given quantity of any one of these.
substances, and I add thereto as much solid alkali and acid, either in a com-
bined state or separately, as that for every part by weight or thereabouts of
alkali, of the strength of the best American pearlash, there shall be one:

page_text: hundred and fifty parts or thereabouts of the gypsum or limestone or chalk,
and I grind the said materials together (by any of the means ordinarily
employed for grinding) to a fine and well-mixed powder. I next calcine the
said powder, which is most conveniently done by spreading it on a hot hearth
or stove similar to such as are employed by colour manufacturers, for a short
time, and afterwards transferring it to an iron cylinder of any convenient size
(similar to such as are used in manufacturing plaster of Paris), which is set in
a furnace in such manner as to be enveloped by the flames or nearly so, and
easily kept at a red heat. In one end of this cylinder there is a door made to
fit very close, through which the powder is introduced, and near to the centre
of it there are two apertures of about half an inch in diameter, which serve
the double purpose of allowing any vapours which may be evolved in the
process of calcination to escape, and a polished iron rod to be thrust through
either of them (without opening the door), in order to ascertain whether the
said process is complete, of which completeness this may be taken as a certain
criterion, that the iron on being withdrawn has no appearance of damp or
moisture upon it. For the sake of heating the cylinder and its contents more
equally, it is kept continuing revolving during the process of calcination, either
by hand or any other suitable means. In directing that either gypsum or
limestone or chalk may be used as aforesaid, for the basis of the cement, I
must be understood as speaking of that description of limestone which
is known in and about London by the name of grey limestone, but limestones
of other qualities may be also used; and with regard to some of these it may be
found advantageous to incorporate a little clay or other earthy substance, which
should be done at the time of grinding the materials together; and instead of
using gypsum or limestone or chalk as the basis of the cement, I occasionally
use gypsum and lime together in equal portions, adding the alkali and acid in
the manner and according to the proportions before specified.
And now to describe the second of my before specified improvements. I
declare that cements may be formed by combining gypsum and lime with a
third substance containing or producing acid, or by combining gypsum and
lime alone, without the addition of any third substance whatever, whether of
an acid or alkaline quality (that is to say) :-To make a cement from gypsum
and lime, with the addition of a third substance containing or producing acid,
about two parts, by weight, of gypsum are to be mixed with about one part of
lime, and for every hundred parts of the lime or thereabouts there is to be
added one part of sulphur, or of some other substance from the addition of
which acid is produced, taking care to increase or reduce the quantity of the
said substance, according as it is superior or inferior to sulphur in its acid

page_text: producing properties. And to make a cement from gypsum and lime alone,
without the addition of any third substance whatever, the gypsum must be
apportioned to the lime according to this rule, that the moisture given
out by the gypsum in the course of calcining them together shall be just
sufficient to slake the lime. Where the lime employed is that which is known
in and about London by the name of the greystone lime, I find that about
two parts of gypsum are required for each part of lime. In the case of both
the cements I have last described, the materials are to be ground together,
calcined, and finished in the same way as has been herein before directed to
be done with respect to the class of cements comprehended under the first head
of my present Specification.
And having described in the Specification of the Patent first herein-before
recited the modes of using the cements resulting from the various combinations
of materials and processes therein described, I declare that the same modes
are equally applicable to the cements produced by the new and improved com-
binations and processes herein-before specified, and that I find it in general of
advantage to use none of the cements in a fresh state.
And having now described the nature of my said invented improvements,
and the manner in which the same are to be performed, I declare that what
I claim under my present Letters Patent, being that second herein-before
described, is,
First, the manufacture of cements from gypsum in its natural state, or from
limestone, or from chalk, or from gypsum and lime in combination with
alkalis and acids in a solid state, without the use of water in any stage of the
operations, excepting only such water as the materials themselves may contain,
and that whether the said alkalis and acids are added in a compound state or
separately.
And second, the manufacture of a cement from gypsum and lime, with the
addition of a third substance containing acid, or producing acid from its com-
bination therewith, but without the addition of any third substance containing
alkali; and also the manufacture of a cement from gypsum and lime alone,
without the addition of any more alkali or acid than is embodied in the said
materials themselves.
And such my said invented improvements being, to the best of my know-
ledge and belief, entirely new, and never before used within that part of Iler
Majesty's United Kingdom of Great Britain and Ireland called England, Her
Dominion of Wales, Town of Berwick-upon-Tweed, or in any of Her said
Majesty's Colonies and Plantations abroad, I do hereby declare this to be my
Specification of the same, and that I do verily believe this my said Specifica-

page_text: tion doth comply fully and in all respects, without reserve or disguise, with the
proviso in the said herein-before in part recited Letters Patent contained.
Wherefore I hereby claim to maintain exclusive right and privilege to my
said Invention.
In witness whereof, I, the said Richard Freen Martin, have hereunto set
my hand and seal, this Second day of December, One thousand eight
hundred and forty.