IMPROVEMENTS IN PREPARING SKINS AND ANIMAL SUBSTANCES FOR OBTAINING GELATINE, SIZE, AND GLUE, AND IN PRE- PARING SKINS FOR TANNING
Year: 1841

page_text: DEAN, of Dover, in the County of Kent, Chemist, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twenty-third day of February, in the fourth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said John Dean, Her especial licence, full power, sole privilege and authority,
that I, the said John Dean, my executors, administrators, and assigns, and
such others as I, the said John Dean, my executors, administrators, or assigns,
should at any time agree with, and no others, from time to time and at
all times 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 in all Her Majesty's Colonies and Plantations
abroad, my Invention of "IMPROVEMENTS IN PREPARING SKINS AND
ANIMAL SUBSTANCES FOR OBTAINING GELATINE, SIZE, AND GLUE, AND IN PRE-
PARING SKINS FOR TANNING;" in which said Letters Patent is contained a
proviso, obliging me, the said John Dean, by an instrument in writing under
my hand 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 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
John Dean, do hereby declare that the nature of my said Invention, and the
manner in which the same is to be performed, are particularly described

page_text: and ascertained in and by the following description thereof, reference being
had to the Drawing hereunto annexed, and to the letters and figures marked
thereon (that is to say) :-
In the first place, for the preparation of hides and skins and other animal
substances for the manufacture of gelatine, size, and glue, I take all such
hides and skins, or pieces of hides or skins or other animal substances, as the
tendons of the fect, as are usually employed in the manufacture of gelatine, size,
or glue, and, if not already done, I deprive them of their horns, hoofs, bony or
fatty matters or parts, and if the hides, skins, or pieces which I may intend to
use have not been deprived of hair, I place them in a solution of lime, or of
the alkalies potass or soda, or combined proportions of either, diffused in water
in the proportion of eight to twenty-six pounds of lime, and from four to six-
teen pounds of potass or soda to every fifty gallons of water, and I permit the
hides or animal substances to remain in this solution not less than twenty-four
hours, by which time the hair will be slightly loosened. The animal sub-
stances, together with a quantity of the said solution, or a similar solution, are
then placed in a rotating cylinder constructed like the Figures in the Drawing
annexed; Fig. 1 being a longitudinal section of the cylinder mounted in proper
bearings in the framework, and Fig. 2 a vertical section. The cylinder is
formed of bars of wood or suitable metal, set at short distances apart, and
secured to strong circular ends of from two to four feet in diameter; some of
these bars must be moveable to allow of the admission of the skins, &c. A per-
forated surface of wood, secured in a similar way to the bars, may be adapted,
in which case a door must be made for the admission of the skins. The cylinder
may revolve by the agency of any required mechanical or manual power in a
case, vat, or trough of any suitable material. This being done, the cylinder is
made to revolve by the action of the before-mentioned power until, by the
action of the lime or the alkalies potass or soda, assisted by the friction of the
internal surface of the cylinder and the animal substances against each other,
the hair becomes removed, together with some of the albumen which such
animal substances contain. The hides, skins, or pieces thus treated are then
taken out of the cylinder and cleansed, fleshed, or shaved, in the ordinary or
any other method, and washed and soaked in water until thoroughly cleansed.
When the hides, skins, or pieces have had the hair removed by the ordinary
method, they only require to be placed in the same or a similar rotating cylin
der to the one before mentioned, and, instead of being washed in a lime or
alkaline solution, they are washed in clear water until properly cleansed. The
hides, skins, or pieces prepared according to either of the two preceding
methods, or the animal substances, such as the tendons, which do not require

page_text: unhairing, are then steeped in a large or suitable vat or tank, and allowed to
remain in water until a slight putrescence is evident; they are then placed in
suitable receivers, constructed either of wood or metal, or some vitrified sub-
stance, as glass or earthenware, and covered with water, and upon them is
poured from six to twenty-eight or thirty pounds of hydrochloric acid for every
one hundred pounds weight of animal substance that the receivers contain ; or
the hydrochloric acid, in either of the above-mentioned proportions, may be
combined with a sufficient quantity of water in a seperate suitable vessel, and
poured upon the hides or skins, or other animal substances, and stirred round
in order to give the mixture access to all parts of their surface. The vessel is
then covered over, and the animal substances exposed to the action of the
acidulated water for a suitable time, varying, according to the kind and age of
the skins, hides, and animal substances, from eight to twenty-four hours. While
experience tells me that the above-mentioned spaces of time are sufficient for
the exposure of those animal substances which are in general use, let the hides
and pieces of the buffalo and other animals, when of unusual bulk or thickness,
will require to be again exposed to the action of a similar solution, and in that
case it would be desirable to wash them carefully before such the exposure.
When the skins and animal substances have been sufficiently exposed to the
action of this mixture, they assume generally a whitened semi-transparent
appearance. The hides, skins, pieces, and animal substances next require to be
washed thoroughly in clear cold water, and in order to do so effectually I know
of no more convenient machine than a rotating cylinder, such as I have before:
described, although stampers or other agents may be used for the same pur-
pose, but in any case the washing should be continued until the water passes
through them perfectly clear and limpid. This washing being completed, the
animal substances are deposited in a tun, vat, or tank accessible to a con-
stantly flowing current of clear fresh water, which is allowed to conver them,
and in which they may remain one, two, or three days, when they are ready to
have their gelatine, size, or glue extracted from them.
Hides or skins intended to be tanned must be submitted to a process like to
the one herein-before described, in order to deprive the hides and skins of their
hair; namely, by the assistance of a rotating cylinder and a solution of lime, or
the alkalies soda and potass; and also a similar process is made use of by the
application of the hydrochloric acid or the acid solution, the proportions in either
case being the same, and dependant upon the same circumstances. When these
processes are completed, the hides and skins are ready to be manufactured into
leather by being exposed to or operated upon by the tanning principle or tannin
in the ordinary way.

page_text: Though I have particularly described the application of the hydrochloric acid
in solution, yet a similar effect may be produced by the exposure of the hides
and skins and other animal substances, in a suitable close vessel, to the action
of the hydrochloric acid gas generated by the usual method, by the action of sul-
phuric acid upon the chloride of sodium, or the same gas may be disengaged
and afterwards absorbed by water, and the animal substances may then be
exposed to its action.
I claim as my Invention, the use of a rotating perforated or other cylinder,
as before described, for the purpose of unhairing the skins or hides or picces to
be used in the manufacture of gelatine, size, or glue, when used in combination
with a solution of lime, potass, or soda, or combined partions of either.
I also claim as my Invention, the application of hydrochloric acid or
hydrochloric acid gas, or hydrochloric acid or hydrochloric acid gas diffused.
in water, in whatsoever manner it may be employed, when applied to hides,
skins, or other animal substances, for the purpose of preparing them for the
manufacture of gelatine, size, or glue.
I also claim as my Invention, the sole application of the above-mentioned
acid and acid gas to hides and skins, for the purpose of preparing them for
being tanned.
And I would observe that I do not limit myself to the employment of these
Inventions in connexion with each other, but I also claim them seperately
and independantly, each being able to be used by itself with effect in conducting
my improved process.
In witness whereof, I, the said John Dean, have hereunto set my hand
and seal, this Twentieth day of August, in the year of our Lord One