CERTAIN IMPROVEMENTS IN THE TREATMENT AND PREPARATION OF CERTAIN NATURAL OR ARTIFICIAL STONES, TO RENDER THEM APPLICABLE TO VARIOUS USEFUL AND ORNAMENTAL PURPOSES
Year: 1853

page_text: PROVISIONAL SPECIFICATION left by Charles Videgrain at the
Office of the Commissioners of Patents, with his Petition, on the
4th May 1858.
(Void by reason of notice to proceed not having been given within the
time prescribed by the Act.)
I. CHARLES VIDEGRAIN, of Paris, in the Empire of France, and of
16, Castle Street, Holborn, (City,) London, do hereby declare the nature
of the said Invention for "CERTAIN IMPROVEMENTS IN THE TREATMENT
AND PREPARATION OF CERTAIN NATURAL OR ARTIFICIAL STONES, TO RENDER
THEM APPLICABLE TO VARIOUS USEFUL AND ORNAMENTAL PURPOSES," to be as
follows, viz
:
The substances used in this process to impregnate the natural or
artificial stone, plaster, &c., are all materials susceptible of being put
into ebullition or fusion, but more particularly those which are resinous
5 or bituminous. These substances are cast separately or mixed into a.
cauldron mounted over a furnace; its form and dimensions may be varied
according to the objects which it is desired to impregnate.
I-have succeeded in impregnating soft stones, natural or artificial, in
all kinds of -cauldrons, but I have observed that in a cauldron about
fifteen feet deep filled with matter to about three feet of the brim gives
the best result, as thus a certain pressure resulting from the weight of

page_text: the matter in fusion is obtained, and that there is less danger of the
dross, which is disengaged at the commencement of the operation,
running over, and which would then become ignited. When the
matter is in a state of fusion it is fit for the operation. There is no
occasion to purify the bituminous or resinous substances used for the
impregnation; it is better to choose those containing much volatile oil,
which penetrating first assists the mixing of the more dense materials,
and then evaporates in the course of the operation of impregnation.
The following method of operating answers well, viz., to soak the objects
in the volatile oils in a state of ebullition, to immerse them in bituminous
or resinous substances purified from their volatile oils, and to keep them
there until the latter are substituted for the former.
APPARATUS FOR PLACING AND WITHDRAWING THE SUBSTANCES FOR
IMPREGNATION IN AND FROM THE CAULDRON.
The objects to be impregnated should be as much as possible freed
from dampness. They should be deposited upon a stand in the form of
a table or framework of wood or iron. This stand has one or several
stages, and arranged so as to receive the objects which it is desired to
impregnate; at its upper part there is a peg or ring, so that by means of
a pulley or other means it may be raised or held suspended with the
objects in the cauldron. This stand or framework should be constructed
with such arrangements that the objects which it is desired to impreg-
nate may not be in contact in the cauldron with its sides or base, because
the objects touching the cauldron would stick to it; this would entail
other inconveniences not less serious. When the stand or framework
is desired to be raised, the part adhering remaining fixed against the
cauldron, the stone becomes uneven; and as this piece becomes an
obstacle it causes a very tiresome displacing of the objects, for during
the impregnation the stones are softened, and thus any displacing can
scarcely be effected without injury to the shape of the article.
It is advisable that the pulley be fixed to a car rolling upon rails
supported by a timberwork, so that the table or loaded framework may
be readily approached and removed from the cauldron.
A crane
turning on an axis could at all events replace the movable pulley.

page_text: MODE OF CONDUCTING THE OPERATION OF IMPREGNATION.
The objects being suspended or immersed in the cauldron the im-
pregnation commences; and that this may be under the best circum-
stances it should take place in the following manner :-The most liquid
and volatile portions of the matter in fusion penetrate first; they are
followed and then replaced by the more dense portions. The impreg
nation having arrived at this point the suspending chain is agitated
with care, so as to clear the objects from the thick substance which
becomes deposited on their surfaces; this agitation causes no injurious
results if the stones are regularly placed. Then the stand or framework,
with the objects which it contains, are withdrawn by the pulley, tackle,
or other apparatus which was used to place them in the cauldron. As
these objects are very soft they are placed with care upon an even
surface, or left to cool; they solidify and pass to the state of hard stone,
having a crystalline appearance. The operation is then continued by
adding to the matter to make up any deficiency, and by placing in the
cauldron another stand or framework furnished with objects to be
impregnated, which have been prepared during the preceding operation
of impregnation, and so on for successive operations.
In case a complete impregnation should not be desired, but solely a
superficial one, that is to say, of the thickness of some lines upon blocks
of a certain dimension, it is essential for this kind of work to employ
substances purified from their volatile oils. This precaution is indis-
pensible, because when the impregnation is stopped before it is completed
the surfaces are hardly penetrated with fixed substances to some lines
that already the essential oils have more deeply penetrated; the parts
penetrated with bituminous or resinous matters remain after the cooling
hard and impermeable. But those penetrated solely by the volatile oils
become and remain soft. In impregnating with matters freed from
their volatile oils this inconvenience does not take place; the impregna-
tion is then limited to the depth desired.
The impregnation taking place under the conditions which I have
just indicated, it cannot be doubted that there would be at and after
the period of their employment, an evaporation of the substances which

page_text: have penetrated the bodies. The impregnated soft stones may be
shaped before they get cool. Plaster articles moulded, or any articles of
a-plaster substance. These articles should be placed in a kind of iron
framework. The moulded articles should first be steeped in.volatile oils.
This will be useless-if- they be placed first in: the cauldron. Then the
matter, either in powder, or small fragments, or liquid, but cold,
be introduced and afterwards heated. 'The articles, when taken out of
the cauldron and cooled, should be rubbed with a hard brush, dry or
with water; then rub the surfaces with a piece of cloth; thus a fine
polish is given. Should the articles not be solid it would be necessary
to make small holes in them to prevent their bursting from the vapours
entering them.
Artificial stone may be made by a process thus:-Chips and frag-
inents of soft stone amalgamated with water or with glutinous matter,
and thrown in the state of a paste into moulds, then impregnated by
the above described process. .
The matter may be coloured.
The stones may be polished, 1st, by being rubbed with..a piece of
fine gritstone: with water and fine sand. 2ndly, by passing over the
surfaces pumice stone dipped in.. water. 3rdly, by rubbing afterwards
with a piece of cloth.
VARNISHING THE STONES OR OTHER ARTICLES IMPREGNATED.
They may be covered with the following varnish
600 grains.of common copal varnish.
400 do. of essence of turpentine.
Impregnated stones to be used for paving purposes should be well
steeped in bitumen before laying them down.