THE PRE- OF PURPLE COLOURING MATTER BY CHLORIDE OF CALCIUM
Year: 1858

page_text: LETTERS PATENT to William Spence, of 50, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "THE PRE-
OF PURPLE COLOURING MATTER BY CHLORIDE OF CALCIUM."-A
communication.
Sealed the 26th October 1858, and dated the 9th August 1858.
PROVISIONAL SPECIFICATION left by the said William Spence at the
Office of the Commissioners of Patents, with his Petition, on the 9th
August 1858.
I, WILLIAM SPENCE, of 50, Chancery Lane, in the County of Middlesex,
Patent Agent, do hereby declare the nature of the said Invention for "THE
PRECIPITATION OF PURPLE COLOURING MATTER BY CHLORIDE OF CALCIUM," (being a
communication from a foreigner residing abroad,) to be as follows:—
Powerful basis, such as lime, magnesia, potash, soda, barytes, strontium,
have heretofore been employed, whether in the manufacture of orchil, or in
the processes of fixing colouring matter on tissues. Thus, in the manufacture.
of orchil, lime has often been employed to regulate the fermentation, or to
obtain particular tints or shades of this colouring matter. Magnesia, potash,
soda, barytes, strontium, &c., have often been used in printing and dyeing as
media, whether for turning the colour, or as tending to fix it when once
deposited on the fibre.
Now, in this Invention metallic oxides are used, and particularly lime in the
state of a salt, but with quite another object. The colour is extracted and
developed according to the process described in the Patent granted to me, as
a communication from abroad, for "Improvements in the Production and

page_text: Application of a Material called French Purple, and in the Process employed in
obtaining it," and bearing date 1st May 1858. Then, in order to extract and
separate the violet colouring principle in its purest state, and freed from the
pale red colouring matter which accompanies it, there is added to the ammo-
niacal coloured liquor a suitable quantity of chloride of calcium, which gives
rise to a double decomposition; first, an insoluble precipitate which contains
the violet matter; secondly, a solution, more or less coloured, in which is
found all the pale red matter.
The precipitate is gathered or collected on a filter, washed with hot or cold
water, then dried with care, and presents the external characteristics of a
light indigo, susceptible of becoming coppered when rubbed with the nail,
and only to be distinguished from indigo from its violet colour. It is in this.
form that it is supplied as an article of commerce. For its use in dyeing, it
is sufficient to dilute it with suitable proportions of water and quantities of
acid necessary to saturate the lime which is found in it. The acids which
may be used for the purpose are principally sulphuric and oxalic, although
any acid may be employed of sufficient energy to seize upon the base..
It has been mentioned, that preference is given to salt of lime, but other
saline compounds may be used that will answer the purpose, whether of pre-
cipitating the violet matter while the pale red matter is in solution, or the
converse, that is to say, of rendering the latter insoluble whilst the violet
matter is held in solution.
In order, however, to avoid all misunderstanding, it may be desirable to
specify these salts which may be used for the purpose, viz., those formed with
one of the oxides of barytes, strontium, magnesium, zinc, bismuth, lead, &c.,
in a word, with powerful salifiable bases.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Spence in the Great Seal Patent Office on the
7th-February-1859..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
SPENCE, of 50, 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 Ninth day of August, in the year of our Lord One
thousand eight hundred and fifty-eight, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto 'me'

page_text: the said William Spence, Her special license that I, the said William Spence,
my executors, administrators, and assigns, or such others as I, the said William
Spence, 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 "THE PRECIPITATION OF PURPLE
COLOURING MATTER BY CHLORIDE OF CALCIUM," being a communication from a
foreigner residing abroad, upon the condition (amongst others) that I, the
said William Spence, by an instrument in writing under my hand and seal,
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 William Spence, 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 (that is to say):-
This Invention for "The Precipitation of Purple Colouring Matter by
Chloride of Calcium," consists in the process herein-after described. Powerful
bases, such as lime, magnesia, potash, soda, barytes, strontium, have heretofore
been employed, whether in the manufacture of orchil, or in the processes of
fixing colouring matter on tissues. Thus, in the manufacture of orchil, lime
has often been employed to regulate the fermentation, or to obtain particular
tints or shades of this colouring matter; magnesia, potash, soda, barytes,
strontium, &c., have often been used in printing and dyeing as media, whether
for turning the colour, or as tending to fix it when once deposited on the
fibre.
66
Now, in this Invention metallic oxides are used, and particularly lime in
the state of a salt, but with quite another object. The colour is extracted
and developed according to the process described in the Specification of a
Patent granted to me, as the receiver of a communication from abroad, for
Improvements in the Production and Application of a Material called
French Purple, and in the Process employed in obtaining it," and bearing
date the First of May, One thousand eight hundred and fifty-eight. Then, in
order to extract and separate the violet colouring principle or agent in its
purest state, and freed from the pale red colouring matter which accompanies
it, there is added to the ammoniacal coloured liquor a suitable quantity of
chloride of calcium, which gives rise to a double decomposition; first, au
:

page_text: insoluble precipitate, which contains the violet matter; and, secondly, a
solution, more or less coloured, in which is found all the pale red matter.
The precipitate is gathered or collected on a filter, washed with hot or cold
water, then dried with care, and presents the external characteristics of a
light indigo, susceptible of becoming coppered when rubbed with the nail,
and only to be distinguished from indigo by its violet colour. It is in this
form that it is supplied as an article of commerce. For its use in dyeing, it
is sufficient to dilute it with suitable proportions of water and quantities of
acid necessary to saturate the lime which is found in it. The acids which
may be used for the purpose are principally sulphuric and oxalic, although
any acid may be employed which is of sufficient energy to seize upon the base.
It has been stated that preference is given to salt of lime, but other saline
compounds may be used that will answer the purpose, whether of precipitating
the violet matter while the pale red matter is in solution, or the converse,
that is to say, of rendering the latter insoluble whilst the violet matter is held
in solution.
In order to prevent misunderstanding, it may be desirable to specify the
following salts which may be used for the purpose, (viz.,) those formed with one
of the oxides of barytes, strontium, magnesium, zinc, bismuth, lead, &c., in
a word, with powerful salifiable bases.
Having thus described the nature of the said Invention communicated
to me as aforesaid, I would have it understood that what I claim under the
above in part recited Letters Patent is, the process herein-before described,
whereby the purple colouring matter is precipitated and freed from the pale
red matter.
In witness whereof, I, the said William Spence, have hereunto set my
hand and seal, the Seventh day of February, in the year of our Lord
One thousand eight hundred and fifty-nine.
Witness,
GEORGE BEDELL COULCHER,
50, Chancery Lane,
Law Stationer.
WILLIAM SPENCE. (L.S.)