IMPROVEMENTS IN THE MANUFACTURE OF PIGMENTS
Year: 1864

page_text: LETTERS PATENT to Ludwig Schad, of Cassel, in the Electorate of
Hesse, at present residing temporarily at Warrington, in the County of
Lancaster, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
PIGMENTS."
Sealed the 3rd January 1865, and dated the 12th July 1864.
PROVISIONAL SPECIFICATION left by the said Ludwig Schad at the
Office of the Commissioners of Patents, with his Petition, on the 12th
July 1864.
I, LUDWIG SCHAD, of Cassel, in the Electorate of Hesse, at present residing
temporarily at Warrington, in the County of Lancaster, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
PIGMENTS," to be as follows:-
My Invention consists in the production and in the application of a green
pigment or colouring matter the chief constituent of which is manganate of
baryta. To obtain this pigment, which I call Cassel green, I proceed in the
following way:-Any of the oxides of manganese, or hydrates of the oxides of
manganese, or carbonate of manganese, is intimately mixed with nitrate, or,
though not so conveniently, with nitrite of baryta. The mixture spread out
in an uniform thin layer on a suitable surface is ignited till it is converted
into a green product. To prevent the mixture from melting, and to ensure a
good and uniform product, either an inactive compound, like sulphate of
baryta and china clay, or oxide of baryum or other suitable substance, is

page_text: previously added to the mixture. I prefer a mixture in the following pro-
portions by weight-Eighty parts of nitrate of baryta, fourteen parts of
oxide of manganese, and six parts of sulphate of baryta. The green product
thus obtained is scraped off from the surface upon which it has been heated
and ground in a mill with water to the desired state of powder. It is essential
for the stability of the product to add a certain quantity, either of gum arabic,
dextrine, silicate of soda and potassa, or other suitable substance, to the moist
pigment. In the case of employing gum arabic I prefer an addition of about
five per cent. The pigment thus obtained is either dried at a temperature of
about 212° F., then powdered and sifted, or it may be used at once in the form
of paste. On drying the moist pigment the caustic baryta contained in it is
almost completely converted into carbonate of baryta. The pigment or
colouring matter obtained in the way herein-before described may be used
conveniently for staining papers, as an oil colour, and for calico printing, and
similar purposes.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Ludwig Schad in the Great Seal Patent Office on the
11th January 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LUDWIG
SCHAD, of Cassel, in the Electorate of Hesse, at present residing temporarily
at Warrington, in the County of Lancaster, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twelfth day of July, in the year of our Lord One
thousand eight hundred and sixty-four, in the twenty-eighth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Ludwig Schad, Her special license that I, the said Ludwig Schad,
my executors, administrators, and assigns, or such others as I, the said Ludwig
Schad, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN THE MANU-
FACTURE OF PIGMENTS," upon the condition (amongst others) that I, the said
Ludwig Schad, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly

page_text: describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Ludwig Schad, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement (that is to say): :-
My Invention consists in the production and in the application of a green
pigment the chief constituent of which is manganate of barium. To produce
this pigment, which I call "Cassel green," I proceed in the following manner:
-I heat an intimate mixture of any of the oxides or hydrated oxides of
manganese or carbonate, nitrate, or other suitable salt of manganese and
nitrate of barium. To prevent the mixture from fusing, and to ensure a good
and uniform product, either an inactive compound, like sulphate of barium
and china clay, or another suitable substance, is previously added to the
mixture.
In using a mixture of oxide of manganese, nitrate of barium, and sulphate
of barium, I prefer the following proportions by weight:-Fourteen parts of
oxide of manganese; eighty parts of nitrate of barium; and six parts of
sulphate of barium.
In using a mixture of nitrate of manganese, nitrate of barium, and sulphate
of barium, I prefer the following proportions by weight:-Twenty-four parts
of nitrate of manganese; forty-six parts of nitrate of barium; and thirty parts
of sulphate of barium. Any of these mixtures are heated in a suitable furnace
till it has assumed a uniform green color. The green product thus obtained
is ground in a mill with water to the required state of fineness. It is essential
for the stability of the product to add a certain quantity of gum arabic,
dextrine, or other similar substance to the moist pigment. In the case of
employing gum arabic I prefer an addition of about five per centum. The
pigment thus obtained is either dried at a temperature of about 212° Fahren-
heit, then powdered and sifted, or it may be used at once in the form of a
paste. The pigment produced as herein described may be used for staining
papers, as an oil color, for calico printing, and similar purposes.
Having thus described the nature of my Invention, and the manner in which
the same is to be carried into effect, I wish it to be understood that I do not
confine myself to the precise details herein-before described, as they may be
varied or modified without departing from the principle of my Invention, but I

page_text: claim the practical production and the application of a green pigment the chief
constituent of which is manganate of barium in the manner herein described.
In witness whereof, I, the said Ludwig Schad, have hereunto set my
hand and seal, this Twenty-seventh day of December, in the year of
our Lord One thousand eight hundred and sixty-four.
Signed, sealed, and delivered by the
within-named Ludwig Schad, in
the presence of
G. SEPTIMUS HUGHES,
Patent Agent,
Manchester.
LUDWIG SCHAD. (L.S.)