IMPROVEMENTS IN CLEANSING, POLISHING, COLOURINH, DYEING BUILDINGS, TOMBS, AND ARTICLES OF MARBLE, STONE, AND OTHER MATERIALS, WORKING AND DYEING MARBLE AND STONE FOR THE SAME
Year: 1881

page_text: LETTERS PATENT to Guillaume Joseph Conrad Marie Baron de Liebhaber,
Engineer, of Avallon (Yonne), France, for an Invention of IMPROVEMENTS IN
CLEANSING, POLISHING, COLOURINH, DYEING BUILDINGS, TOMBS, AND ARTICLES
OF MARBLE, STONE, AND OTHER MATERIALS, WORKING AND DYEING MARBLE
AND STONE FOR THE SAME."
PROVISIONAL SPECIFICATION left by the said Guillaume Joseph Conrad
Marie Baron de Liebhaber at the Office of the Commissioners of Patents on
the 23rd September 1881.
GUILLAUME JOSEPH CONRAD MARIE BARON DE LIEBHABER, Engineer, of
Avallon (Yonne), France. IMPROVEMENTS IN CLEANSING, POLISHING, COLOURING,
DYEING BUILDINGS, TOMBS, AND ARTICLES OF MARBLE, STONE, AND OTHER
MATERIALS, WORKING AND DYEING MARBLE AND STONE FOR THE SAME."
My Invention consists in the employment of certain chemical agents and
apparatus or appliances for bringing these agents into action on the surface of
stones or materials of like kind, for the purpose of cleansing, polishing, working,
colouring, or dyeing them.
In order to produce a white tint I apply sulphuric acid, which acts on the
superficial carbonate of lime, converting it into sulphate of lime, which is whito
and adheres to the stone.
In order to cleanse soiled stone facings I apply sulphuric acid diluted with
water and mixed with common salt or salt petre, or with other chlorides or
nitrates, or even with hydrochloric or nitric acid, the effect of these additions
being to prevent the sulphate of lime from adhering to the stone. I then remove
the sulphate along with the impurities by washing and rubbing.
In certain cases use hydrochloric acid of the strength of one part of gas to
4 to 9 parts water. To prevent the acid from acting irrugularly employ linen
or other flexible material arranged in a frame, suited to the surface treated, to

page_text: maintain the acid on the paris to be acted on, and to remove the soiled liquid
resulting from the chemical action and the subsequent washing.
I generally prefer however to employ a mixture of hydrochloric and sulphuric
acids and water, which require no special apparatus for its application. The
proportions of the mixture should be nearly as follows:-
375 parts by volume of hydrochloric acid at 20° to 21°,
50 parts by volume of sulphuric acid at 64° to 65°,
And water sufficient to make the mixture at 15° to 16°.
I apply this mixture first in a thin layer, which produces a kind of coating. I
then pour it on in larger quantity, causing a thick paste to form on the stone.
After a little time I sprinkle this with a little water to promote the reaction, and
finally I wash and brush the stone, which then appears with its original colour.
Sulphate of alumina or other sulphates may be used instead of sulphuric acid.
By adding chloride or other salt of peroxide of iron I give the stone a yellow
tint, and by adding sulphate of copper obtain a greenish tint.
For the purpose of merely cleansing, giving polish or brilliancy, I apply vapour
of hydrochloric acid, produced by boiling in a bath of chloride of calcium, liquid
hydrochloric acid, of the strength of one part of gas to four of water.
I direct this vapour on the surface by a nozzle at the end of a flexible tube,
which may consist of a number of lengths of copper or glass tubes with caoutchouc
junctions. The nozzle should not touch the stone, but should be kept at a little
distance from it, such as a quarter of an inch, or less. When it is desired to
cleanse or polish only, the nozzlo is moved rapidly over the surface; when it is
desired to work or shape the surface, the nozzle is directed and kept directed on
the parts to be hollowed until the stone is corroded to the required depth.
Instead of thus vaporising a solution of hydrochloric acid, 1 may obtain the
acid gas for use as above described by the action of concentrated sulphuric acid
on the chloride of ammonium, calcium, magnesium, or other chloride. I bring
the gas thus generated to act on the surface which is previously wetted with
water, or may direct a current of steam along with the acid gas, so as to
produce more energetic action.
For operating on stone that is not readily acted on by acids, I direct on the
points to be acted on a current of superheated steam (which may be generated
from water or from the combustion of hydrogen or hydrogenous compounds)
with or without the aid of oxidising substances or chemical reagents.
In order to give new or cleaned stone a green colour, 1 employ a solution of
chloride or nitrate of copper, or of compounds producing either of these. The
solution may be applied to the surface by a brush, or the stone may have its
surface immersed in a bath of the solution. Otherwise a piece of linen or other
porous material soaked in the solution may be applied repeatedly to the surface.
or a paste may be made consisting of sulphate of copper mixed with chloride of
calcium or nitrate of lime, and this paste may be spread over the surface, to
which it will adhere, and left to act till it loses its colour.
Stone thus dyed green can be rendered black by application of sodium sulphide
or other hydro-sulphate compounds. By employing sodium sulphide of suitable
strength, and stopping the operation at a certain point, and then washing and
rubbing, a blue colour can be obtained.
The green tint is suitable for architectural ornament, and the black for tombs,
monuments, and the like, or for inscriptions or lines of architectural ornament.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Guillaume Joseph Conrad Marie Baron de Liebhaber in the Great
Seal Patent Office on the 21st March 1882.
GUILLAUME JOSEPH CONRAD MARIE BARON DE LIEBHABER, Engineer, of
Avallon (Yonne), France. "IMPROVEMENTS IN CLEANSING, POLISHING, COLOURING,
DYEING BUILDINGS, TOMBS, AND ARTICLES OF MARBLE, STONE, AND OTHER
MATERIALS, WORKING AND DYEING MARBLE AND STONE FOR THE SAME."
My Invention consists in the use of certain chemical agents hereinafter named,
and of certain apparatus or appliances for bringing these agents into action on the
surface of stone or other materials for the purpose of cleaning, polishing, colour-
ing, or dyeing, or otherwise treating thein.
1. In order to produce a more or less white tint on the surfaces I employ pure
sulphuric acid; for this purpose it is simply spread by means of a brush in a thin
layer on the surface, thus transforming to a slight depth the carbonate of lime
into sulphate of lime, which adheres to the stone and renders it white. When
it is desired to clean the stone without whitening it I employ sulphuric acid
diluted with from 4 to 6 times its weight of water, in which salt, saltpetre, or
any other chlorinated or nitrated body has been dissolved. The effect of this
mixture is to prevent the sulphate of lime formed from adhering to the stone.
It is removed, together with the dirt and impurities, by washing and rubbing.
2. In certain cases I employ cold liquid hydrochloric acid for cleansing. For
this purpose I take the hydrochloric acid, perfectly free from iron, and as much
as possible from other metals. I dilute it with at least 4 times, and at most
9 times, its weight of water, and I apply it to the stone to be cleaned by means
of cloths that are held in frames, whereby the acid is made to act for a longer
time and more uniformly. The acid is poured on the cloth in a thin stream or a
line spray. For surfaces of small extent I employ simply a brush passed over
several times with or without the use of a cloth.
Figs. 1, 2 and 3 of the accompanying Drawings shew in front view, vertical
transverse section, and horizontal section, an apparatus adapted for this pur-
pose intended for a vertical surface.
3. I employ more generally a mixture formed of 375 parts by volume of hydro-
chloric acid, of 20° to 21° Beaumé, and of 50 parts by volume of sulphuric acid,
of 64° to 65°, together with sufficient water to bring the mixture to 15° to 16°.
For part or the whole of the sulphuric acid may be substituted a chemically
equivalent quantity of an earthy sulphate, in particular the sulphate of alumina,
which I prefer for delicate work. I add perchloride of iron if it is desired to
impart a yellow tint, and 1 use pure acids if the stone is to retain its natural
tint. I apply this mixture first by means of a brush in a thin layer, producing
a kind of coating, upon which I pour a larger quantity of the mixture by means
of an injector such as that shewn at Fig. 4, or of similar apparatus. c is a vessel
filled with the acid mixture; d is a handle held in the hand; f, a tube entering
the vessel, but not dipping in the liquid; g is a caoutchouc pump worked by the
other hand for producing pressure in the vessel; i, a removeable part screwed on
to the end of the spout, and having one or more very fine jets. By the above
means a thick paste is formed which acts on the stone, and which is revivified
after some time by pouring on water. After the action has ceased the surface
is washed and scrubbed, taking care to use brushes having no iron in their con-
struction.
Fig. 5 shews a form of brush constructed with gutta percha a, and having a
hood for preventing the scattering of the liquid.
4. When cleaning mouldings, sculpture, or surfaces that require to remain or

page_text: become very uniform, or that require to be very brilliant, or for which the use
of cold acid is insufficient, I employ the vapour of hydrated hydrochloric acid, or
dry hydrochloric acid gas combined on the spot with water or steam, as will be
presently described, which means constitute the most powerful agent of those
described, and which form the most important part of my Invention. This
vapour is produced by heating in a bath of chloride of calcium or dilute sulphuric
acid hydrochloric acid perfectly free from iron, having 13° to 14°, and contain-
ing one part of gas to 4 parts of water. The vapour thus produced is conveyed
by a flexible tube to the part to be cleansed, the tube having a conical nozzle
when recessed or hollow surfaces are to be acted upon, as at Fig. 7, or spreading
nozzle (Fig. 8) for surfaces with projections; or I employ a plate having conical
perforations (Fig. 9) for smooth surfaces, taking care that the nozzle or plate
does not come in immediate contact with the stone, but that a small space is left
between them. The nozzle or perforated plate is moved slowly and uniformly
over the part to be cleaned or polished, taking care to remove at once the dirty
liquid produced by means of a brush, and if necessary to wash. When it is
desired to impart brilliancy to a part already cleaned I pass the steam over it in
the same manner, but I then dry without washing. Fig. shews an apparatus
for this purpose. Instead of hydrochloric acid vapour I can use dry hydrochloric
acid gas produced by the action of sulphuric acid upon chloride of ammonium,
magnesium, calcium, or other chloride. I convey this gas, like the acid vapour,
to the parts to be cleansed, préviously moistened, or I apply simultaneously a jet
of steam.
5. When imperfectly cut or polished stone is to be acted upon, in order to
render it smooth and shining I employ the vapour of acid, as described with
reference to the cleaning process, but I apply it by means of a perforated plate
provided with a handle, as indicated in longitudinal section and plan at Figs. 10
and 11. This plate ; may, by way of example, be made about 10 inches long
and 6 to 7 wide, formed of vulcanite, porcelain, or other material that will resist
the acid vapour. It is provided with a rim about inch wide on the side
applied to the stone, and it has conical holes about one inch apart, to which aro
attached tubes m for conveying the acid vapour thereto, which tubes are con-
nected to the socket n communicating with the supply pipe o
This plate is
passed to and fro over the surface, while bearing with its rim against the rough
surface until this is sufficiently smooth and shining.
6. When the objects to be cleaned are covered with organic matter, such as
carbon or fatty substances that withstand the action of the above named chemi-
cals, 1 effect or facilitate their removal by directing upon them a jet of steam
superheated to the degree at which it becomes oxidising, or a jet of any other
oxidising gas, such as vapour of nitric acid, so as to burn, decompose, or dis-
aggregate the said substances. This oxidising jet can be produced by a blow
pipe or other known apparatus used in the arts.
7. I employ the deuto chloride or the nitrate of copper, or mixtures forming
such compounds for dyeing the stone green, by transforming the carbonate of
limo to a slight depth into hydrocarbonate of copper; after which, by means of
the latter, I obtain black, bronze, or blue colours. For this purpose I apply to
the surface to be dyed a solution of deuto-chloride of copper, or of nitrate of
copper or aqua regia, in which the copper is dissolved, applying the same several
times by means of a brush, or by covering the surface with a cloth saturated with
the solution, which is again saturated when discolored; or I apply the liquid as
a bath by means of a box hermetically attached to the stone; or I employ a paste
formed of sulphate of copper and of chloride of calcium applied to the stone, to
which it adheres after a time, losing its color. The stone thus dyed green is
rendered black by putting it in contact with a dilute solution of sodium sulphide,
or of any other hydrosulphate, and in only partially carrying out this process I
obtain a bronze tint. I obtain a blue color in applying to the green tinted stone
a solution of caustic soda; or I employ during a very short time sodium sulphide

page_text: partially decomposed, containing soda in a caustic state, after which the surface
is washed.
8. I complete the cleansing process by applying a coating of chlorido of lime
for removing the coloring matters which have penetrated more or less deeply
into the stone, and have not disappeared on removing the superficial coating.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim in respect of the cleansing, polishing, coloring,
dyeing, and working of natural or artificial stone or cement,-
-
First. The use of sulphuric acid, either in a pure state or mixed with chlorides
or nitrates, for cleansing or whitening.
Second. The use of pure liquid hydrochloric acid suitably diluted for cleansing
either with the brush or by means of cloths saturated with the acid.
Third. The use of hydrochloric acid mixed with sulphuric acid or aluminium or
other sulphate, and acting on the stone in the form of adhesive paste, for
cleansing the same.
Fourth. The use of hydrochloric acid vapour for cleansing, by means of the
described or other apparatus, for imparting lustre and preserving the stone.
Fifth. The use for treating stone of dry hydrochloric acid gas and steam or
water applied separately.
Sixth. The use of acid vapour for dressing the surface of stone, and imparting
thereto smoothness and brilliancy.
Seventh. The use of a jet of superheated steam or of an oxidizing gas for
facilitating the removal of the carbonaceous or other impurities on the surface to
be treated.
Eighth. The use of nitrate and deuto chloride of copper for dyeing stone green,
and of sulphides and caustic alkalies for producing black, bronze, and blue
colors.
Ninth. The use of the hereindescribed processes for cleansing or beautifying
buildings, tombs, and other objects of calcareous stone, or of artificial stone or
calcareous cements.
In witness whereof I, the said Guillaume Joseph Conrad Marie, Baron de
Liebhaber, have hereunto set my hand and seal, this Twentieth day of
March, in the year of our Lord One thousand eight hundred and eighty-
BS. DE LIEBHABER. (L.S.)