CERTAIN IMPROVEMENTS IN THE MANU- PACTURE OF SILK HATS
Year: 1823

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
HOPPER, of Reading, in the County of Berks, Esquire, send greeting.
WHEREAS His most Excellent Majesty King George the Fourth did,
by His Letters Patent under the Great Seal of that part of the United
Kingdom of Great Britain and Ireland, called England, bearing date at West-
minster, the Twentieth day of November, One thousand eight hundred and
twenty-three, in the fourth year of His reign, give and grant unto me, the
said Thomas Hopper, my exors, admors, and assigns, His especial licence, full
power, sole privilege and authority, that I, the said Thomas Hopper, my exors,
admors, and assigns, during the term of years therein mentioned, should and
lawfully might make, use, exercise, and vend, within England, Wales, and the
Town of Berwick-upon-Tweed, and also in all His Majesty's Colonies and
Plantations abroad my Invention of "CERTAIN IMPROVEMENTS IN THE MANU-
PACTURE OF SILK HATS;" in which said Letters Patent there is contained
a proviso, that if I, the said Thomas Hopper, shall not particularly describe
and ascertain the nature of my said Invention, and in what manner the
same is to be performed, by an instrument in writing, under my hand and
seal, and cause the same to be enrolled in His Majesty's High Court of
Chancery within six calendar months next and immediately after the date of
the said Letters Patent, that then the said Letters Patent, and all liberties
and advantages whatsoever thereby granted shall utterly cease, determine, and
become void, as in and by the same, relation being thereunto had, will more
fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Thomas Hopper, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, are particularly described
and ascertained in the following description thereof, that is to say):-
METHOD OF MANUFACTURING THE NEW PATENT SILK HATS,
The woollen substance which forms the basis is first to be boiled in a solu-
tion of the supersulphate of alumine and potas's (common alum) for about
two hours, in the proportion of two or three pounds of alum to a gallon of
water, it is then to be taken out, well rinsed in clear water, and wrung,
and immediately dipped in a solution of isinglass or glue, of variable strength,
at à boiling heat, and put on a frame to dry and give it a shape. The
cloth thus prepared, and before or when it becomes quite dry, may be
again immersed in a strong solution of acetate or tartrate of alumine. The
acetate thus made:-Alum about three pounds, sugar of lead one pound, dis-
solved seperately in a gallon of water, & then mixed and decanted.) (The tar-
trate thus made:-Dissolve about two pounds and a half of alum and one pound
& a half of cream of tartar in a gallon of boiling water; this need not be
strained) or supersulphate, and allowed to remain in the liquor for a few
hours; it may then be rinsed and dried as before. This liquor must not be hot.
A third method is to dip the cloth (previously alumed) in a solution of
gelatin and one of the aluminous salts added together; when wrung immerse it
once or twice in an alkaline lixivium; afterwards dry as before. By these pro-
cesses the gelatin is set or fixed in what may be termed the first, second, and
third degree; and the manufacturer may use the first singly or combined with
the second, as directed, or the third only. In the last process a double
chemical change is effected, the acid of the aluminous salt leaves it and
attaches itself to the alkali, while its base, the alumine, combines with the
gelatin, renders it insoluble in water, and together with it remains affixed
to the cloth. Various important advantages appear to be derived from the
alumining process; it effectually removes the grease from the wool, by which
conjoined with its strong affinity for the cloth and gelatin, between which there
exists but little naturally,-it acts as a powerful intermedium in fixing the latter,
enables it to resist the action of water, from the absorption of which, when
used in its simple state, and consequent increase of volume, appears to arise one
of the principal causes of the disjunction and falling to powder of the resinous
gums,-it
prevents the cloth from shrinking in any sensible degree when sub-
sequently wetted facilitates the adhesion of the gums with the wool, and serves to
equipoise those materials that are fusible by heat. The resinous gums may now

page_text: be applied in the same manner as at present practised, or they may be used in
the humid way dissolved in a spirituous menstruum with a portion of Venice
turpentine. It is usual to mix a third or fourth part of rosin or sandarack with
the lac, but the mastiche is preferable, not curling up in cooling like the sanda-
rack, and possessing more tenacity than either; it contains a substance analagous
to caoutchoue. Caoutchoue or elastic gum. Dissolved in rectified oil of turpen-
tine, and rendered drying by pure alumine by washed olther, or which is more
economical, as much acetate of alumine as it will absorb; they should be
rubbed together. It is intended for the rim, but a discretion is left with the
manufacturer in its application. Between the resinous gums and the varnish
an intervening substance, not fusible by heat, is necessary to prevent the latter
from subsiding; isinglass dissolved in weak spirits, gum, acacia, simple or pure
aluminous paste, &c. suffice; the pure alumine is also used inside mixed with
common or resinous paste. Pure alumine is obtained by pouring on a solu-
tion of alum a solution of potass, soda, or ammonia, washing the precipitated
powder once or twice with boiling water, and after filtering, drying the
powder. The varnish, either that in common use or the following, may be
employed, asphaltum four parts, gum mastiche or animi two or three parts,
drying linseed oil from two to three parts; melt the bitumen and gum in an
iron vessel over a charcoal fire; then add the oil; when all mixed remove the
vessel from the fire; add Venice turpentine two parts, and gradually six or
eight parts of essential oil; strain; if it should be too thick when cool, add more
of the essential oil. The proportions here given admit of being varied.
In witness whereof, I, the said Thomas Hopper, have hereunto set my
hand and seal, this Nineteenth day of May, in the year of our
Lord One thousand eight hundred and twenty-four