CERTAIN IMPROVEMENTS IN THE MANUFACTURE OF MATERIALS USED IN THE DYING OF BLUE AND OTHER COLOURS
Year: 1838

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
WATSON Junior, of Leeds, in the County of York, Manufacturing Chemist,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters*
Patent under the Great Seal of Great Britain, bearing date at Westminster,
the Eighth day of November, in the second year of Her reign, did, for Her-
self, Her heirs and successors, give and grant unto me, the said William
Watson, Her especial licence, full power, sole privilege and authority, that
I, the said William Watson, my executors, administrators, and assigns, and
such others as I, the said William Watson, my executors, administrators,
and assigns, should at any time agree with, and no others, from time to time
and at all times during the term of years therein expressed, should and
lawfully might make, use, exercise, and vend, within England, Wales, and
the Town of Berwick-upon-Tweed, my Invention of "CERTAIN IMPROVEMENTS
IN THE MANUFACTURE OF MATERIALS USED IN THE DYING OF BLUE AND OTHER
COLOURS;" in which said Letters Patent is contained a proviso that I, the
said William Watson, shall cause a particular description of the nature of
my said Invention, and in what manner the same is to be performed, to
be inrolled in Her Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the said in part recited
Letters Patent, as in and by the same, reference being thereunto had, will
more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said.
William Watson, do hereby declare that the nature of the said Invention, an:l¨

page_text: the manner in which the same is to be performed, is particularly described
and ascertained in the following explanation thereof, that is to say:
My Improvements in the Manufacture of Materials used in the Dyeing of
Blue and other Colours consist in certain processes of preparing indigo in
order to render it more applicable to the purposes of dyeing wool, cotton, silk,
and other similar materials, either in the raw. or manufactured state, and also
in adapting such materials to the general demand of commerce and manufac-
turers upon a large scale. In order that the improvements may be more
readily understood, I deem it necessary to describe one ordinary manner of
operating upon indigo. to improve its colour, and make it more available for
the purposes of dyeing; which has hitherto been as follows:-The indigo is
ordinarily dissolved in sulphuric acid, and by filtering the solution, which has
been previously diluted with water, the grosser and impure parts of the indigo
are separated from the finer. To this filtered solution is afterwards added
some salt or alkali, which precipitates the blue colouring matter in combina-
tion with the sulphuric acid: The precipitate being collected upon à filtër, is
How of the consistency of paste; and known in commerce as "extract of
indigo." The excess of uncombined acid which this produce contains is
sometimes for the still further improvement of the colour, and also for the
convenience of dyers, removed by various operations; the details of which it is
not necessary here to pursue: Now my improvement in this process; and in
order to ensure the complete neutralization of the acid, thus rendering the
colour thore Beautiful and pure; and securing the absence of all free uncom
Bined acid, is as follows I employ the hydrate of alumina in the manufac
ture of extract of indigo;" and in the following simple manner :---When
the indigo has been dissolved in sulphuric acid; passed through the process
already described, and the uncombined acid removed as much as possible by
the ordinary, means; I add to it hydrate of alumina, or allum and ammonia,
potash or soda, or any other materials which by their mutual decomposition
produce the hydrate of alumina, and, after mixing these well together, I place
the mixture upon a filter, and allow it to remain until the paste is of sufficient
'consistency for sale or use.
Another method I employ in order to improve the colour and quality of
indigo to be used for dyeing is, instead of dissolving the indigo in sulphuric
acid, as above described as the ordinary practice, I 'dissolve it in water by the
assistance of copperas and lime, or orpiment and lime, or by other agents by
which indigo may be dissolved in water, such as potash, soda, or ammonia, tin;
Woad, &c.; and when such solution is made it is allowed to remain at rest
until the insoluble part of the indigo and materials employed have subsided.

page_text: I then draw off the clear liquor, and by exposing it to the action of the
atmosphere the blue colouring matter of the indigo is precipitated, which
precipitate is to be collected upon a filter, mixed with diluted sulphuric or
muriatic or any other acid, washed with water, and, lastly, dried, by which
refining process I produce a beautiful and very pure indigo. And also for a
still further improvement of the colour of indigo, and for the more convenient
use of it, I take indigo refined by the process just described, and dissolve it in
concentrated sulphuric acid, and this solution of refined or purified indigo in
sulphuric acid I call liquid extract of indigo.
Lastly, I desire it to be understood that I do not intend to claim such
common or known processes as have been above alluded to, but the adapta-
tion of such process or processes upon a large scale for the purpose of
commerce and manufactures, and applying the product to the purposes of
dyeing, and also the manufacture and application of liquid extract of indigo
to the purposes of dyeing wool, woollen cloths, silk, cotton, or other goods or
materials.
In witness whereof, I, the said William Watson, have hereunto set my
hand and seal, this First day of May, in the year of our Lord One
thousand eight hundred and thirty-nine.
AND BE IT REMEMBERED, that on the First day of May, in the
second year of the reign of Her Majesty Queen Victoria, the said William
Watson came before our said Lady the Queen in Her Chancery, and
acknowledged the Instrument aforesaid, and all and every thing therein
contained and specified, in form above written. And also the Instrument
aforesaid was stamped according to the tenor of the Statute made in the fifty-
fifth year of the reign of His late Majesty King George the Third.