A CERTAIN IMPROVEMENT OR IMPROVEMENTS, OR PROCESS OR PROCESSES, APPLICABLE TO THE PRINTING OF COTTON AND OTHER CLOTHS, AND TO OTHER PURPOSES
Year: 1818

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSHUA
ROWE, of Torpoint, in the County of Cornwall, Merchant, send greeting:
WHEREAS His present Majesty King George the Third did, by His
Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Fourth day of May now last past, for Himself, His heirs
and successors; give and grant unto me, the said Joshua Rowe, His especial
licence that I, the said Joshua Rowe, my executors, administrators, and
assigns, or such others as I or they should at any time agree with, and no others,
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 "A CERTAIN IMPROVEMENT OR IMPROVEMENTS, OR
PROCESS OR PROCESSES, APPLICABLE TO THE PRINTING OF COTTON AND OTHER CLOTHS,
AND TO OTHER PURPOSES;" in which said Letters Patent there' is contained a
proviso obliging me, the said Joshua Rowe, by an instrument in writing under
my hand and seal, particularly to describe and ascertain the nature of my said
Invention, and in what manner the same is to be performed, and to cause the
same to be inrolled in His Majesty's High Court of Chancery within six
calendar months next and immediately after the date of the said Léttérs
Patent, as in and by the same, reference being thereto. had, will' more fully
and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Joshua Rowe, do hereby declare that my said Invention is fully and
particularly described in manner and form following, that is to say:-
My Invention consists in making an aluminous sulphate proper to be used
as a substitute for alum in the processes of printing calico or other cloths;
and this I effect by a direct combination of the acid known in commerce by
the name of oil of vitriol with any aluminous earth, as the Cornish porcelain
earth or pipe clay, or any other clay not charged with much iron, though even
these will answer the purpose, but not so well, unless when it may be desirable
to produce a larger quantity of Prussian blue in the said process or processes,
as described hereafter; and the said combination is effected in manner follow-
ing: Mix in a lead vessel oil of vitriol with clay, previously pulverized, in
such proportions that when thoroughly mixed the mass may be of the con-
sistence of a thick paste or soft clay. If the porcelain clay be that which is
employed, it answers best in the state in which it is when prepared for sale to
the potters. If any other clay, it should be pulverized as already stated.
Make the paste into cakes of a few pounds weight each, and lay them in any
convenient situation for some days, taking care to sift or strew previously
upon the boards, stones, or tiles on which they are laid some powdered clay.
These cakes are then to be put into any oven or furnace in which they may con-
veniently be brought to a dull red heat, taking care not to suffer any fuliginous
or coaly matter to mix with them, and the possibility of this happening may
be prevented by inclosing the cakes in earthen vessels of any convenient
size before putting them into the oven or furnace. The cakes, whether inclosed
in earthen vessels or not, should be powdered over with pulverized clay, to
assist in preventing any unnecessary waste of acid. Let the fire bo raised by
degrees, and when the required heat has been obtained, and has been main-
tained for about half an hour or from that to an hour, then withdraw the fire,
and suffer the whole to cool, pulverize the baked composition, expose it for a
few days to the atmosphere, turning or stirring it from time to time, and then
in a lead cistern pour over it water (either hot or cold, but hot answers best,)
in the proportion of about one gallon to every pound of the oil of vitriol used.
Stir the whole well, and afterwards draw off the liquor; add more water, and
proceed as before, and repeat this washing till the water when drawn off is
almost or quite tasteless. The liquor thus obtained is a solution of
aluminous sulphate, produced by the chemical union of the acid with the
aluminous earth of the clay employed, and the whole (previously filtered, when
that may be necessary,) is to be evaporated till concentrated to its required
strength, if to be used on or near the spot, but if to be afterwards removed to

page_text: thousand eight hundred and eighteen.
JOSHUA ROWE. (L.S.)
AND BE IT REMEMBERED, that on the same Fourth day of November,
in the year above mentioned, the aforesaid Joshua Rowe came before our Lord
the King in His Chancery, and acknowledged the Specification aforesaid, and
all and every thing therein contained, in form above written. And also the
Specification aforesaid was stamped according to the tenor of the Statute in
that case made and promised.