IMPROVEMENTS IN PREPARING SOLUTIONS AND EXTRACTS OF THE COLOURING MATTER OF MADDER AND OTHER TINCTORIAL SUBSTANCES FOR DYEING AND PRINTING
Year: 1857

page_text: LETTERS PATENT to Charles Cowper, of No. 20, Southampton Buildings,
Chancery Lane, in the County of Middlesex, Patent Agent, for the
Invention of "IMPROVEMENTS IN PREPARING SOLUTIONS AND EXTRACTS OF
THE COLOURING MATTER OF MADDER AND OTHER TINCTORIAL SUBSTANCES FOR
DYEING AND PRINTING."-A communication from Ferdinand Mitscherlich,
of Eilenburg, in Prussia.
Sealed the 10th November 1857, and dated the 16th May 1857.
PROVISIONAL SPECIFICATION left by the said Charles Cowper at the
Office of the Commissioners of Patents, with his Petition, on the
16th May 1857.
"
I, CHARLES COWPER, of No. 20, Southampton Buildings, Chancery Lane, in
the County of Middlesex, Patent Agent, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN PREPARING SOLUTIONS AND EXTRACTS OF
THE COLOURING MATTER OF MADDER AND OTHER TINCTORIAL SUBSTANCES FOR
DYEING AND PRINTING," to be as follows:-
I have found that the phosphate of soda and other soluble phosphates, and
also the alkaline arseniates, exercise a powerful solvent action upon madder
and its preparations, and upon other tinctorial substances.
I employ solutions of the aforesaid phosphates and arseniates to extract or

page_text: dissolve the colouring matter from madder, flowers of madder, garancine,
garancene, alizarine, and other tinctorial substances, and I thus obtain richer
and stronger, solutions or, extracts than those ordinarily obtained. I employ
these solutions or extracts for dyeing and printing in the ordinary manner.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Cowper in the Great Seal Patent Office on the
11th November 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
COOPER, of No. 20, Southampton Buildings, Chancery Lane, in the County of
Middlesex, Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of May, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twentieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Charles Cowper, Her special licence that I, the said Charles Cowper,
my executors, administrators, and assigns, or such others as I, the said
Charles Cowper, 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
PREPARING SOLUTIONS AND EXTRACTS OF THE COLOURING MATTER OF MADDER AND
OTHER TINCTORIAL SUBSTANCES FOR DYEING AND PRINTING," communicated to
me from Ferdinand Mitscherlich, of Eilenburg, in Prussia, upon the condition
(amongst others) that I, the said Charles Cowper, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly 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 Charles Cowper, do hereby declare
the nature of the 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 thereof, that is to say:→
The madder is first reduced to powder and freed from some of the impurities,
such as salts, sugar, gum, and mucilage, by treating it with water, which

page_text: after a maceration of about a day may be squeezed out; or water acidulated
by sulphuric or other acid may be employed, or both water and acidulated
water may be used in succession. The acid mixture may be beated to the
boiling point if necessary to facilitate the action of the acid, which is afterwards
drawn off or separated by filtration, and the residue is washed until the last
washings are no longer acid. The madder thus purified is ready for the
second process.
The various concentrated preparations or extracts of madder, known in
commerce under the various names of flower of madder, garancine, garancene,
alizarine, and the impure extracts obtained by the solvent action of alcohol
or wood spirit, and the caustic alkalies on madder, and the residues of madder
after dyeing, are only submitted to the aforesaid process if they still contain
impurities, but are otherwise treated at once by the second process in the
following manner :-The purified madder or any of the aforesaid preparations
is mixed. with a quantity of hot water equal to from ten to twenty times its
weight, considered in a dry state, and the mixture is well stirred. The last
traces of acid, if any was employed before, and which can never be entirely
removed by washing, are then neutralized by a small quantity of caustic
alkali or alkaline carbonate. Phosphate of soda or other alkaline phosphate;
calcined or not, or an alkaline arseniate, is then added, in quantity equal to
from one to three per cent. of the weight of the water employed. The
colouring matter is thus dissolved. The mixture is well stirred, and steam
is passed through it, and the whole is then filtered through a felted tissue
or other porous material. The filtration may be accelerated by pressure or
a centrifugal hydro-extractor. These operations are repeated if necessary till
the water no longer extracts any colour.
The solution of colouring matter thus obtained may be concentrated in
various ways, either by evaporation or by employing it to dissolve a fresh
quantity of colouring material, or by adding a salt of alumina or tin or iron
to obtain a precipitate or lake, or, more advantageously, by adding sulphuric
or other suitable acid, or common salt or other suitable salt, which precipitates
the colouring matter in a flocculent state, and it is then collected on a filter.
It may be dried or not, and washed if necessary. To obtain a strong solution
of it an alkaline phosphate should be employed. These products may be
employed in various ways for dycing and printing.
The colouring matter can be purified by digesting the aforesaid dried
product in alcohol or wood spirit, which dissolves the colouring matter, which
is obtained in a paste or in a dry state by precipitating it by the addition of
water. A strong solution of it or of the aforesaid impure extracts, which

page_text: may be employed in printing and dyeing, is obtained by dissolving either of
them in a solution of phosphate of soda or other alkaline phosphate. This
mode of proceeding is also applicable to the extraction of the colouring
matter of some other tinctorial substances, such as munjeet, wild madder, or
bedstraw...
The herein-before mentioned proportions are found to produce a good
result, but they admit of being varied to a considerable extent without much
difference in the result.
Having now described the nature of the Invention, and in what manner
the same is to be performed, I wish it to be understood that what I claim is,
preparing solutions and extracts of the colouring matter of madder and other
tinctorial substances for dyeing and printing by means of the alkaline phos-
phates and arseniates, as herein-before described.
In witness whereof, I, the said Charles Cowper, have hereunto set my
hand and seal, this Eleventh day of November, in the year of our
- Lord One thousand eight hundred and fifty-seven.
CHARLES COWPER. (L.S.)