AN IMPROVED PROCESS FOR PRODUCING ARTIFICIAL MARBLE
Year: 1877

page_text: A
LETTERS PATENT to William Edward Newton, of the Office for Patents, 66,
Chancery Lane, in the County of Middlesex, Civil Engineer, for the Inven-
tion of AN IMPROVED PROCESS FOR PRODUCING ARTIFICIAL MARBLE."
cominunication from abroad by Harriet G. Hosmer, of Rome, in the Kingdom
of Italy.
t
led the 20th November 1877, and dated the 30th June 1877.
PROVISIONAL SPECIFICATION left by the said William Edward Newton at
the Office of the Commissioners of Patents on the 30th June 1877.
WILLIAM EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Civil Engineer. "AN IMPROVED PROCESS FOR PRODUCING
ARTIFICIAL MARBLE." [A communication from abroad by Harriet G. Hosmer, of
Kome, in the Kingdom of Italy.]
Artificial marbles are usually composed of cement or plaster mixed with other
materials, so that the compound may be cast or moulded into any desired forin;
or an ornamental marbled surface may be produced on any suitable hard surface
by a process of enamelling."
The present Invention differs from these processes, inasmuch as ordinary lime-
stone in a solid state is the foundation of the artificial marble.
In carrying out the Invention the limestone is cut into any desired form, such
as slabs or tessera for pavements, or in the form of vases, blocks, pedestals, figures,
mouldings, or cornices. The pieces of limestone are placed in a boiler supplied
with water, and heated until the pressure within has reached 5 degrees of atmo-
spheric pressure. The limestone is to remain in this bath for from 12 to 18 hours,
and when taken out it is to be placed in another bath consisting of a solution of
alum in water, in which it must remain for 24 hours or longer. It may be left in
this bath for a week, or even a month, as it will daily acquire greater strength and
hardness.
Instead of boiling the limestone in water under pressure it may be subjected to
the action of steam under pressure, the object of this part of the process being to
subject the articles to the action of a damp or wet heat under pressure for several
hours.

page_text: The stone when taken from the alun bath may pass into the hands of the
polisher if in the shape of plain blocks or slabs, but if it be in the form of a statue,
vase, or other ornamental work of art, it may be placed in the hands of an artist
to finish, as the stone does not attain its greatest hardness until it has become
perfectly dry, which will require a fortnight, more or less, according to the size of
The object.
The above process will not appreciably alter the natural colour of the limestone ;
but if it be desired to give the appearance of colored marbles the alum bath must
have added to it coloring matters, so as to produce on the surface of the stone the
color desired.
A black color may be produced by a mixture of red wood, fustick wood, the
sulphates of iron and copper, and acetic tincture of iron. This mixture will harden
as well as colour the stone.
The various aniline colors dissolved in water may also be used for coloring and
bardening the stone.
Dye woods of various colors, with the addition of carbonate or tartrate of potash
and borax, may also be used, as also may indigo and other coloring matters.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Edward Newton in the Great Seal Patent Office on the
29th December 1877.
WILLIAM EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the
AN IMPROVED PROCESS FOR PRODUCING
County of Middlesex, Civil Engineer.
ARTIFICIAL MARBLE." A communication from abroad by Harriet G. Hosmer, of
Rome, in the Kingdom of Italy.
Artificial marbles are usually composed of cement or plaster mixed with other
materials, so that the compound may be cast or moulded into any desired form ;
or an ornamental marbled surface may be produced on any suitable hard surface by
a process of enamelling.
The present Invention differs from these processes, inasmuch as ordinary lime-
stone in a solid state is the foundation of the artificial marble.
The Invention may therefore be described as consisting in an improved method
or process for preparing limestone or any other stone of like nature, or having lime
for its basis, by which process the hardness and beauty of natural marble in its
various colors may be obtained.
In carrying out the Invention the limestone, or other stone having lime for its
basis, is taken in its natural state and reduced to whatever forṛn may be desired,
whether as statues, monuments, fountains, vases, pedestals, architectural decorations
of all kinds, columns for gateways, jambs for doors, slabs for steps, or other purposes,
squares, octagons, or other forms of tesseræ for pavements or any other form
whatsoever.
The limestone or other substance may be brought to the desired form by means
of the chisel, the saw, the lathe, the plane, or by any other instrument which may
prove more convenient, and the work should be carefully finished before it is sub-
mitted to the process of petrifaction hereafter described. The objects thus prepared,

page_text: or reduced to the desired forin are placed in a boiler of suitable dimensions to
receive them.
The boiler should be furnished with a safety valve and manometer, so that the
pressure therein may be noted and controlled as may be required.
The objects may be placed in the boiler, either enclosed in a cage in which they
are packed or they may be placed in the boiler without the cage.
In either case it is more convenient to fill the boiler with water after the
articles have been packed in. The boiler is then filled with pure water at
the ordinary temperature, care being taken that there is no mineral deposit
introduced with the water. Care must also be taken that the water completely
covers the objects placed within the boiler. The boiler is then hermetically sealed,
and it is well that there should be a strip of lead between the lid and the body of
the boiler. The fire is then applied and the water allowed to boil until the mano-
meter indicates five degrees of atmospheric pressure if the objects are small, and six
or seven degrees of pressure if the objects are large. When the heat reaches the
above-mentioned point the water is allowed to cool until the pressure indicated by
the manometer returns to zero. The water is then taken out of the boiler either
by means of a pump or a syphon. The objects are then to be removed from the
boiler preparatory to being placed in the alum or colored bath. If, however, steam
alone can be introduced into the boiler (always maintaining the above-mentioned
degree of heat and pressure) the result attained will be the same, the action of
steam, not the presence of water, being necessary for acting on the stone.
If steam can be supplied (from a neighbouring engine), for instance, the process
would be more economical.
It is necessary here to remark that care must be taken that the boiler be lined
in such a manner that no rust can discolor the water, and there should be a grating
placed at the bottom of the boiler and raised a few inches above the actual bottom,
so that the earthy particles which become detached from the stone articles in the
process of boiling or steaming, should not adhere to the lower pieces or articles..
=
When it is desired that the objects should retain the natural color of the stone,
the alum bath, in which they are then placed, should consist of pure water con-
taining five degrees of alum, as indicated by the areometer. The articles must
remain in this bath at least twenty-four hours, but they may be left in the same
bath for a week, or for.a month even, by which time they will acquire still greater
hardness; the stone will however have become sufficiently petrified for all ordinary
purposes in the space of the above-mentioned twenty-four hours.
If pure water be used in the boiler, according to the process first described, instead
of steam, the alum bath may be effected in the boiler itself, thus avoiding the
necessity of removing the objects; but it must be remembered that the application
of alum is only admissible when it is intended to preserve the natural color of the
stone. In such case the alum is put in the water before the boiling commences; and
the objects must remain in the boiler for twenty-four hours after the pressure, as
indicated by the manometer, returns to zero.
The articles when taken from the alun bath may pass into the hands of the
polisher if in the form of plain blocks, slabs, or flat pieces; but if they be in the
form of statues, busts, vases, columns, or other ornamental works of art, they may
be placed in the bands of an artist to finish, if required, as the stone does not
attain its greatest hardness until it has become perfectly dry, which will require a
fortnight, more or less, according to the size of the object.
When it is desired to impart color to the stone the colored baths are prepared in
the manner indicated below, in which the objects must be immersed and must
remain therein at least twenty-four hours. The colored baths must be boiling, or
very nearly so, and it is better to remove the objects to be colored from the first
Loiler and place them in the colored liquid while they are still warm from the
team or water. There is no danger, however, of injuring the stone even if it
should be put into boiling liquid while cold, or into cold water while the articles

page_text: are still heated, but the colour penetrates deeper when both stone and bath are in a
heated state.
oven at a
If it be desired to place an object a second time in the coloured bath in order
that it may acquire a deeper colour, it should first be placed in an
temperature of from eighty to ninety degrees, in which it may remain ten minutes, a
after which it may be immersed in the colored bath.
To produce black or dark grey colour,-
Take of pure water
Red wood
Fustick wood
=
-
Sulphate of iron
Sulphate of copper
litres,
2.
grammes, 300,
grammes, 120.
"2
ود
10.
21.
Boil the red wood and the fustick wood for an hour and a half, then add the
sulphites, and continue the boiling until all the salts are dissolved. Three or four
minutes will probably be sufficient for this purpose; the solution may then be passed
through a sieve, and half a tumbler of acetic tincture of iron added. This acetic
tincture of iron may be made by putting small pieces of rusty iron in strong
vinegar, leaving them in for a length of time. The longer the iron remains in the
vinegar the stronger of course will be the solution.
Stone color or lighter grey is made in the same manner and with the same
quantity of water, but with half the quantity of all the other substances; but care
must be taken to refill the vase in which the liquid is prepared, as the water
evaporates by boiling.
In order to prepare a red coloring solution, take of,—
Pure water
Brazilian wood
Scotaus
Cream of tartar
Alum
3 litres.
grammes, 330.
5.
"
gramme,
1.
1.
23
Boil the mixture until all the colour of the wood is extracted, and then pass the
solution through the sieve in order to remove therefrom any solid matters that may
be held in suspension therein.
A yellow color is obtained by adding to,-.
Three litres of pure water,
Extract of yellow wood of Cuba
Sulphite of magnesia or alum
-
"
grammes, 20.
10.
"
The mixture must be boiled until complete solution of extract is effected.
In order to obtain a green color dissolve in,--
Three litres of pure water,
Extract of yellow wood of Cuba, twenty grammes; and
Ten gramines of alum.
Boil the ingredients as above, and then add carefully (by means of a wooden
spoon, and keeping at a certain distance) as many drops of acid sulphate of indigo
(Saxon blue) as may be necessary to give tone of color desired.
To ascertain the depth of colour pour a few drops upon white paper or dip a piece
of dry plaster of paris in the solution.
For a blue color dissolve,-
Alum
grammes, 10.
Acid sulphite of indigo, 20 grammes in 8 litres of water, until the
desired color is obtained.
As all the varied colors of aniline penetrate the stone perfectly, they may be used
at pleasure. It is only necessary to dissolve the colour selected in a little alcohol,
which is afterwards diluted with warm water, in which alum is dissolved in the
The solution may
proportion of twenty-four grains of alum to every litre of water.
be even stronger of alum; this is for colours which are insoluble in water.
such aniline colours as are soluble in water no alcohol is necessary.
For

page_text: They may be dissolved in boiling water in which a little alum or sulphate of
magnesia is introduced; care must be taken to select only those colors which are
duable. The same colors which are permanent in cloth are permanent in stone,
and in general the same rules which apply to the art of dyeing cloth may be
applied to the art of dyeing stone.
Pavements which are colored, particularly if the color is very delicate and if
there be fear of dampness, are better laid down in cement of a light colour. For the
darker colors the cheaper darker cement is equally good. For the stone, of which
the natural color is preserved, no cement is absolutely necessary unless the place in
which they are to be laid is particularly damp.
After the objects have been taken out of their respective baths they are allowed
to dry, during which process the work may be retouched, if necessary. When dry
they are reduced to a fine surface by means of pumice stone, after which a still finer
surface may be given by means of a piece of slate, or still better, of lead, after
which they may be rubbed with oil.
When the oil is dry the articles may be rubbed with phosphate of lime, and the
lustre will be rendered perfect.
The ordinary methods of polishing marble will apply to the polishing of petrified
marbles prepared by the above improved process.
Having now described the Invention of this improved process for producing
artificial marble, which has been communicated to me from abroad, and having
explained the manner of carrying the same into effect, I claim as the Invention
secured to me by Letters Patent as aforesaid,―
Producing artificial marble by subjecting limestone or other calcareous substances
to the action of steam or boiling water under pressure, subsequently to a solution
of alum, as and for the purpose herein set forth.
I also claim subjecting limestone or other calcareous substances to the action of
steam or boiling water, and then steeping the articles or substances so treated in
solutions of coloring matters for the purpose of imparting color thereto, as herein
set forth.
In witness whereof, I, the said William Edward Newton, have hereunto set
my hand and seal, the Twenty-eighth day of December, in the year of our
Lord One thousand eight hundred and seventy-seven.
W. E. NEWTON. (L..S.)