IMPROVEMENTS IN COLOURING STONES FOR BUILDING AND OTHER PURPOSES
Year: 1884

page_text: I LOUIS ERNEST ARTHUR ERICH DANIEL DE LIEBHABER, Gentleman of
2 Bellevue Terrace, Crondance Road, Fulham, London S.W. in the county of
Middlesex do hereby declare the nature of my invention for IMPROVEMENTS
IN COLOURING STONES FOR BUILDING AND OTHER PURPOSES, to be as follows:-
The object of my invention is to change, particularly into red, the colour of
certain sorts of Bath-stones yellow sandstones and other stones, so as to make
them more suitable for architectural purposes, without impairing their quality.
I obtain this result by the mere action of heat properly applied without the
introduction of any dying or other substance and I proceed as follows:
In a box or any other suitable receptacle 6 feet long and 4 feet wide or such
other size as may be found convenient, constructed of any substance resisting a
moderate fire, iron or brick for example, heated underneath or on the sides by any
known means, I introduce lead in sufficient quantity to make, when melted, a bath,
say 6 to 10 inches deep, and I heat it till it becomes liquid. I then bring by
means of a crane or rollers or otherwise, the stones to be treated, either raw or in
their approximate or definitive shape, as the case may be, in the box or receptacle
and let them float on the lead first on one side and then on the other side or sides
by turning them over at proper intervals. According to the nature of the stone or
the desired tint, the lead must be kept at the melting point (a temperature
generally convenient) or it may be heated over that point, what is easily done by
properly conducting the fire. Or when operating on a constant sort of stone
requiring a fixed degree of heat (which should be ascertained before) the melting
point may be lowered or increased at that degree by adding to the lead a propor-
tion of tin in one case or of iron in the other.
The box had better be closed or covered, so as to prevent a useless deperdition of
heat, though it is not material the change in the stone taking place at the surface
in contact with the lead and propagating itself inwards above the surface of the
bath.
After a stone has been submitted in this way to the action of heat for a time
which depends on its nature and size and the intensity of the colour required,
generally 2 hours or about, it is taken out of the bath and others substituted in its
stead, noting the time at which each stone is brought in and the manufacturing
process may go on without interruption,

page_text: Instead of a bath of melted lead, I may use any other sort of oven or furnace to
heat the stone provided by some means the temperature around the stone is
maintained at the proper degree as stated before and long enough to penetrate to
the core.
The stone will be found red inside as well as outside and will keep that
colour in air or water just as the natural sandstone or other red stones which have
been probably reddened of old, after their formation, by some such agency as the
one now artificially applied.
To enhance the shade of the stone, I may after it has been taken out of the box
or the oven, immerge it in a solution of chloride of calcium which has the effect of
keeping the stone moist and then giving it a deeper tint.
The stones thus prepared, either dry or moistened by chloride of calcium can be
cut, shaped, or sculptured and used for building, for ornaments or other purposes
and will be found to harmonize better than white or yellow stone, with the red
brick now in use.
.
• They may be ground to a red or pink powder which may be used for stuccoes
and artificial stone.
Tender Bath-stone and other similar stuffs reddened in the same way can be
used in lieu of what is commonly known under the name of hearthstone, to, whiten
the stairs, copings, window-sills etc., in front of the houses to which they will
impart a pink or reddish tint pleasing to the eye.

page_text: I LOUIS ERNEST ARTHUR ERIC DANIEL DE LIEBHABER, Gentleman of 2 Belle-
vue Terrace, Crondance Road Fulham S.W. in the county of Middlesex do hereby
declare the nature of my invention for IMPROVEMENTS IN COLOURING STONES
FOR BUILDING AND OTHER PURPOSES and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
The object of my invention is to change, particularly into red or pink, the colour
of certain sorts of Bathstone yellow sandstones and other stones, so as to make
them more suitable for architectural purposes, without impairing their quality.
I obtain this result by the mere action of heat properly applied, without the
introduction of any dyeing or other substance: and I proceed as follows:
In a tank or any other suitable receptacle, 6 feet long and 4 feet wide or such
other size as may be found convenient, constructed of any substance resisting a
moderate fire, iron or brick for example, and heated underneath or on the sides by
any known means, I introduce lead in sufficient quantity to make, when molten, a
bath aay 6 to 10 inches deep and I heat it till it becomes liquid. I then bring by
means of a crane, of rollers or otherwise, the stones to be treated either in blocks
or in their approximative or definitive shape, as the case may be, in the tank and
let them float on the lead first on one side and then on the other side or sides by
turning them over at proper intervals. Instead of allowing the stones to float on
the lead, I may immerse them entirely in the bath by means of some system of
machinery producing a pressure over them, in which case they will be brought
more rapidly to the required degree of temperature and the operation consequently
hastened. According to the nature of the stone, the lead must be kept at its
melting point (a temperature generally convenient) or it may be heated over that
point, which is easily done by properly conducting the fire. Or when operating on
a constant sort of stone requiring a fixed degree of heat (which should be ascer-
tained before) the melting point may be lowered or increased to that degree by
adding to the lead a proportion of tin in one case or of zink in the other.
The tank or receptacle used should be closed or covered so as to prevent a useless
deperdition of heat though it is not material, since the change in the stone takes
place at the surface in contact with the lead and propagates itself inwards above
the surface of the bath.
After a stone has been submitted in this way to the action of heat for a time
which depends upon its nature and size (about 2 hours for a column 8 inches in
diameter) it is taken out of the bath and others are substituted in its stead, noting
the time at which each stone is brought in and the manufacturing process may
thus go on without interruption.
Instead of a bath of molten lead I may use any other sort of oven or furnace to
heat the stone, provided by some means the temperature around the stone be
maintained at the proper degree as stated before and long enough to penetrate to
the core.

page_text: The stone will then be found red inside as well as outside and will keep that
colour in air or water just as the natural red sandstone or other red stones which
have probably been reddened of old after their formation by some such agency as
the one now artifically applied.
The stones thus prepared can be cut, shaped and carved and used for building
purposes, and will be found to harmonize better than white or yellow stone with
the bricks now in use..
They may also be ground to a red or pink powder which may used in lieu of
what is commonly known under the name of hearthstone for the purpose of
whitening the stairs, landings, copings window-sills etc. in front of houses, to
which they will impart a pink or reddish tint pleasant to the eye.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. Changing the colour of Bathstone yellow sandstone and certain other stones,
by submitting them to the action of heat at a proper temperature as stated
before.
2. Using for that purpose a bath of molten lead or of any alloy fusible at the
required temperature.
3. Using stone reddened by this process and ground for making artificial stone
stuccoes, hearthstone or other compositions.