IMPROVED ARTIFICIAL GRANITE, STONE, MARBLE, OR CONCRETE
Year: 1839

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
ROBERT D'HARCOURT, of Howland Street, Fitzroy Square, in the County
of Middlesex, Gentleman, send greeting.
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 Sixth day of March, in the third year of the reign, did, for
Herself, Her heirs, and successors, give and grant unto me, the said George
Robert D'Harcourt, Her especial licence, full power, sole privilege and
authority, that I, the said Georgo Robert D'Harcourt, my exors, admors,
and assigns, or such others as I, the said George Robert D'Harcourt, my exors,
admors, or assigns, should at any time agree with, and no others, from time to
time and at all times during the term of years therein mentioned, should and
lawfully might make, use, exercise, and vend, within England, Wales, and.
the Town of Berwick-upon-Tweed, and also in all Her Majesty's Colonies and
Plantations abroad, my Invention of "IMPROVED ARTIFICIAL GRANITE, STONE,
MARBLE, OR CONCRETE;" in which said Letters Patent is contained a proviso,
that I, the said George Robert D'Harcourt, shall and will cause a particular
description of the nature of my said Invention, and the manner in which 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, I, the said
George Robert D'Harcourt, do hereby declare the nature of my said Invention,.,

page_text: and the manner in which the same is to be performed, are fully ascertained
and set forth in and by the following description of the mode of making my
improved artificial granite, stone, marble, or concrete, and of applying the
same to various purposes, that is to say:-
I first cast a quantity of resin into a melting pot, and when the resin is
perfectly melted I add linseed oil or tallow thereto in proportion to the degree
of ductility I wish to give the mixture. The quantity of oil which may be
added, is from one pint to one gallon to a ton of resin, and the quantity of
tallow, about from one pound to eight pounds to a ton of resin. The purpose
of adding the linseed oil or tallow being to give the resin such a degree of
ductility as will enable it to mix with the other ingredients herein subsequently
directed to be added; the exact proportions to be used will depend greatly on
circumstances, and must be left to the experience and judgment of the operator.
I next add to this liquidised resin about twice its weight of whiting or chalk
well pulverized, and stir or agitate the whole till the resin, the oil or tallow, and
the whiting or chalk are thoroughly mixed and incorporated with one another,
taking particular care to distribute the whiting or chalk as equally as possible
throughout the whole mass, and that none of it is left in the state of lumps or
patches. I now leave this composition or mastic to stand for about one hour,
and then withdraw it from the melting pot in the form of loaves by means of
wooden or other moulds; these loaves are now ready for going through the
following additional processes, in order to convert them into artificial granite
or stone; I put one or more of these loaves again into the melting pot, and
when they are perfectly melted I add well picked oakum or other suitable
fibrous substance in the proportion of about ten pounds to a ton of the other
material, stirring all the while the ingredients of the pot with a spatula or
other agitator. When the oakum or other fibrous material has been well
incorporated with and diffused throughout the mastic, I add from six to eight
times the weight of the mastic of perfectly dry sand, stirring again till the
sand is thoroughly mixed with the other materials. The whole of this com-
position or mixture is then left to boil for about two hours, after which it is
in a state fit to be applied as a substitute for natural granite or stone in
manner following, that is to say:-
For pavements. The ground having been duly prepared, a first layer of
the composition is spread thereon, (being taken from the melting pot in a
fluid or semi-fluid state,) to the thickness of about one-fourth of that intended
to be given to the whole block or stone. Another layer is afterwards added of
three-fourths the thickness of the first, and its surface smooth by means of

page_text: hot irons. Railway blocks, columns, pillars, urns, slabs, blocks for building,
or other articles usually cut or hewn out of natural stone or granite may be
made of this composition by casting it in moulds of the desired shape.
To make artificial marble.-I take the mastic or composition made as first
herein before directed and melt it in a clean melting pot, taking great care in
the course of melting that no particles of soot, coal, wood, or other foreign
matter get into the composition, which might make the polishing of the
artificial marble, into which it is to be formed, difficult if not impossible. When
the mastic or composition is perfectly fluid, I add thereto thrice its weight
of pulverized whiting, and stir the whole well together, after which the pot is
to be left to boil for about two hours; I then add natural marble of different
colours broken into small pieces, in the proportion of two parts for each part
of the resinous and chalky composition; the pieces into which the natural
marble is broken must not be so large as that any of them shall get detached
in the course of polishing the artificial marble, as herein-after directed, so as
to leave holes and flaws in the surface thereof. Instead of the broken marble
small pebbles, or large pebbles, or flint, broken into small pieces may be used;
in which case the flint or pebbles must be perfectly clean and dry, with no
particles of earth, or rt, or sand adhering to them. This mixture must be
left to boil for about an hour, and must be stirred the while so as thoroughly
to intermix and incorporate the ingredients with one another.
The mode of applying this composition so as to produce an artificial marble
suitable for tesselated or other pavements is as follows:-The ground or floor
upon which it is intended to lay the pavement being duly prepared, the whole sur-
face is to be covered with a first layer or foundation of the artificial marble com-
position, of about one-fourth of. the entire thickness of the intended pavement.
The design or pattern desired to be given to the pavement is formed in zinc or tin
moulds or frames, of three-fourths the depth of the first layer or foundation,
and these moulds or frames being placed upon the first layer or foundation,
the fluid composition, prepared as aforesaid, is to be poured into them; as
soon as the contents of one set of patterns or designs is hard and dry, the
metal frames or moulds are to be removed; and a further portion of the
pattern proceeded with, and so on to the outer border or edge of the piece of
pavement or parquetry to be formed. The surface of pavement so formed
being perfectly dry and hard, may be ground and polished in the same way
that natural marbles are polished. When the surface is made perfectly
smooth and to the eye perfectly homogenous, a varnish of gum lac may be
passed over it. The artificial marble whether employed for pavement or other
purposes will be, to a certain degree, of the colours of the materials of which

page_text: it is composed, but in every case the appearance will be more or less that of
natural marble.
And having now fully described my said Invention, and the manner in which
the same is to be performed, I declare that what I claim as new and of my
Invention is, the mode or modes herein-before described of making an artificial
granite, stone, marble, or concrete; and I declare that I do not confine myself
to the precise proportions of ingredients herein-before indicated, or the pre-
scribed order of their addition to one another, or to the precise lengths of
times which they are directed to remain combined between each operation
herein-before described, although those which I have stated are what I would
recommend, and have found in practice to be most beneficial; and such my
Invention. being, to the best of my knowledge and belief, entirely new and
never before used within that part of Her said 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 Specification doth comply in all
respects fully and 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 George Robert D'Harcourt, have here-
unto set my hand and seal, this Sixth day of September, One thousand
eight hundred and thirty-nine.