IMPROVEMENTS IN THE PRODUCTION OF YELLOW AND ORANGE COLORING MATTERS
Year: 1863

page_text: LETTERS PATENT to John William Slater, of Huddersfield, in the County
of York, Manufacturer of Mordants and Colours, for the Invention of
"IMPROVEMENTS IN THE PRODUCTION OF YELLOW AND ORANGE COLORING
MATTERS."
Sealed the 2nd February 1864, and dated the 7th August 1863.
PROVISIONAL SPECIFICATION left by the said John William Slater at
the Office of the Commissioners of Patents, with his Petition, on the
7th August 1868.
I, JOHN WILLIAM SLATER, of Huddersfield, in the County of York,
Manufacturer of Mordants and Colours, do hereby declaro the nature of the
said Invention for "IMPROVEMENTS IN THE PRODUCTION OF YELLOW AND ORANGE
COLORING MATTERS," to be as follows:--
My improvements have for their object the production of certain yellow
and orange coloring matters from substances, which have not been hitherto
employed for such purposes, and consist in submitting hides or leather or the
refuse or clippings of the same, or other similar animal substances to the action
of nitric acid, whereby I obtain oxalic acid, and amongst other products the
said yellow and orange coloring matters.
In carrying out my Invention, I employ hides, or leather, or clippings, or
the refuse thereof by preference in a state of division, and nitric acid by pre-
ference of a strength of about 62 degrees Twaddle, and I employ such divided
animal matters in the proportion by preference of about one pound in weight to
every three or four pounds by weight of nitric acid, of the strength before

page_text: mentioned. I add the animal substances before mentioned to the nitric acid
in a large vessel taking care that the operation be so conducted that the tem-
perature does not become too elevated by reason of such reaction. When
the action of the nitric acid on the animal substances has ceased the products
are allowed to cool, and any fatty or other bodies that may rise to the surface
are to be skimmed off and removed. The clear liquor after filtration or
decantation is to be concentrated by the application of heat, and the oxalic
acid formed is to be crystallized out as far as practicable. The mother liquor
will contain the coloring matters, and they may be employed atonce for the
dyeing of silk, wool, or of textile fabrics, or the coloring matters may be
subjected to further purification before being so employed.
I do not confine myself exactly to the above-mentioned proportions of
the said substances, and acid, or to the above-mentioned strength of the
acid, as such proportions and strength will differ according to the animal
substances employed, and with reference to the colors it may be desired to
obtain.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John William Slater in the Great Seal Patent Office
on the 6th February 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
WILLIAM SLATER, of Huddersfield, in the County of York, Manufacturer of
Mordants and Colours, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of August, in the year of our Lord One
thousand eight hundred and sixty-three, in the twenty-seventh year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
John William Slater, Her special license that I, the said John William
Slater, my executors, administrators, and assigns, or such others as I, the said
John William Slater, my executors, administrators, or 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 "Ix-
PROVEMENTS IN THE PRODUCTION OF YELLOW AND ORANGE COLOURING MATTERS,"
upon the condition (amongst others) that I, the said John William Slater,
my executors or administrators, by an instrument in writing under my

page_text: hand and seal, or under the hand and seal of one of them, 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 John William Slater, do hereby
declare the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement, that is to say :-
My said Invention has for its object the production of certain yellow and
orange coloring matters from substances which have not been hitherto employed
for such purposes, and consists in submitting hides or leather, or the refuse or
chippings of the same, or other similar animal substances to the action of nitric
acid, whereby I obtain oxalic acid, and amongst other products the said yellow
and orange coloring matters.
In carrying out my Invention I employ hides, or leather, or chippings or
the refuse thereof by preference in a state of division, and nitric acid by pre-
ference of a strength of about 62 degrees Twaddle, and I employ such divided
animal matters in the proportion by preference of about one pound in weight
to every three or four pounds by weight of nitric acid of the strength before
mentioned, I add the animal substances before mentioned to the nitric acid
in a large vessel, taking care that the operation be so conducted that the
temperature does not become too elevated by reason of such reaction. If
leather be used it must not have been dyed or stained with any prepara-
tion of iron, as such leather would produce a buff dye instead of a pure yellow.
When the action of the nitric acid on the animal substances has ceased the
products are allowed to cool, and any fatty or other bodies that may rise to
the surface are to be skimmed off and removed. The clear liquor after filtra-
tion or decantation is to be concentrated nearly to dryness by the application
of a very gentle heat, and the oxalic acid formed is to be crystallized out as
far as practicable. This concentration is best not performed continuously
but should be interrupted from time to time, and the liquid allowed to cool
to facilitate the separation of the oxalic acid. The oxalic acid thus formed
allowed to drain, the drainings
may be placed in an earthenware strainer and
being added to the mother liquor. The thick mother liquor will contain
the coloring matters, and they may be at once after being diluted with
water employed for the dyeing of silk, wool, or of textile fabrics, or the
coloring matters may be subjected to further purification before being so
employed.

page_text: If it be desired to obtain the colour in a state of greater purity the mother
liquor is evaporated very cautiously to dryness to remove nitric acid, is
redissolved in water, and to the solution powdered chalk is added until no
further oxalic acid can be found in the liquid by the tests usually employed
by chemists. The clear yellow liquid is then decanted off from the white
sediment, which is washed in pure water, and tho washings are added to
the clear liquid. From the white sediment, which is oxalate of lime, the
oxalic acid may be recovered by the addition of sulphuric acid as is well
known to chemists.
I do not confine myself exactly to the above-mentioned proportions of
the said substances and acid, or to the above-mentioned strength of the
acid, as such proportions and strength will differ according to the animal
substances employed, and with reference to the colors it may be desired to
obtain,
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe in conclusion that what I consider to be novel
and original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent, is, the treatment of hides and
leather, and the refuse or chippings of the same, and other similar animal
substances for the production of yellow and orange coloring matters therefrom
substantially in the manner herein-before described.
In witness whereof, I, the said John William Slater, have hereunto
set my hand and seal, the Fourth day of February, Ono thousand
eight hundred and sixty-four.
AVE STATED
JOHN WH
THE STATED
SL
TRENG TAL