IMPROVEMENTS IN THE PREPARATION OF RED AND PURPLE DYES."
Year: 1860

page_text: LETTERS PATENT to Henry Medlock, of Great Marlborough Street, in
the County of Middlesex, Analytical Chemist, for the Invention
"IMPROVEMENTS IN THE PREPARATION OF RED AND PURPLE DYES."
PROVISIONAL SPECIFICATION left by the said Henry Medlock at the
Office of the Commissioners of Patents, with his Petition, on the
18th January 1860.
I, HENRY MEDLOCK, of Great Marlborough Street, in the County of
Middlesex, Analytical Chemist, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE PREPARATION OF RED AND PURPLE DYES,"
to be as follows:-
I mix anilene with dry arsenic acid, and allow the mixture to stand for
some time, or I'accelerate the operation by heating it to or near to its boiling
point until it assumes a rich purple colour, and I then mix it with boiling
water and allow the mixture to cool, when cold it is filtered or decanted.
The aqueous solution which passes through the filter contaius a red.colouring
matter or dye, while a tarry substance remains on the filter; this tarry sub:
stance dissolved in alcohol, methylated spirit, or other suitable spirit furnishes
a purple die. These solutions of colouring matter may be used. at once in
the process of dyeing, concentrated: or diluted according to the tints required.

page_text: The mixture of anileno and arsenic acid after being heated may be allowed to
cool, and then forms a paste which may be preserved; when required for use
it is mixed with boiling water and treated as above described.
.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Medlock in the Great Seal Patent Office on the
17th July 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
MEDLOCK, of Great Marlborough Street, in the County of Middlesex,
Analytical Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of January, in the year of our
Lord One thousand eight hundred and sixty, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Henry Medlock, Her special licence that I, the said Henry Medlock,
my executors, administrators, and assigns, or such others as I, the said
Henry Medlock, 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
PREPARATION OF RED AND PURPLE DYES," upon the condition (amongst others) that
I, the said Henry Medlock, my executors or administrators, 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 Henry Medlock, do hereby declare the
nature of the said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement
thereof, that is to say:-
I mix aniline with dry arsenic acid and allow the mixture to stand for some
time, or I accelerate the operation by heating it to or near to its boiling
point until it assumes a rich purple colour, and I then mix it with boiling
water and allow the mixture to cool, when cold it is filtered or decanted. The
aqueous solution. which passes through the filter contains a red colouring

page_text: matter or die, while a tarry substance remains on the filter, this tarry sub-
stance dissolved in alcohol, methylated spirit, or other suitable spirit, furnishes
a purple dye. These solutions of colouring matter may be used at once in
the process of dyeing, concentrated or diluted according to the tints required.
The mixture of aniline and arsenic acid after being heated may be allowed to
cool, and then forms a paste which may be preserved; when required for use
it is mixed with boiling water and treated as above described.
I have found that the proportion of two parts by weight of aniline to one
part by weight of arsenic acid yields a good result, but I do not confine myself
to that proportion as it admits of variation.
Having now described the nature of my said Invention, and in what manner
the same is to be performed, I wish it to be understood that what I claim is, the
manufacture or preparation of red and purple dies by treating aniline with
arsenic acid as herein-before described.
In witness whereof, I, the said Henry Medlock, have hereunto set my
hand and seal, this Sixteenth day of July, in the year of our Lord One
thousand eight hundred and sixty.
HENRY MEDLOCK. (L.S.)