AN IMPROVE- MENT OR IMPROVEMENTS IN TANNING HIDES AND SKINS
Year: 1831

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
DRAKE, of Bedminster, near the City of Bristol, Tanner, send greeting.
WHEREAS His present most Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Seventh day of October, in the second year of His reign,
did, for Himself, His heirs and successors, give and grant unto me, the said
William Drake, His especial licence that I, the said William Drake, my
exors, admors, and assigns, or such others as I, the said William Drake,
my exors, adiñors, 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 expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, my Invention of "AN IMPROVE-
MENT OR IMPROVEMENTS IN TANNING HIDES AND SKINS;" in which said Letters
Patent is contained a proviso obliging me, the said William Drake, 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 said Majesty's
High Court of Chancery within six calendar months next and immediately
after the date of the said 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 Drake, do hereby declare the nature of my said Invention to consist
in causing tannin to enter into hides or skins, by supplying cold tan liquor to

page_text: one side of the skin, and evaporating by artificial heat from the other side of a
portion of the moisture which oozes through it, whereby the strongest portion
of the tannin is left in the hide or skin, while the strength of the liquor
continually increases during the tanning process, instead of becoming weaker,
as in the ordinary course of proceeding. By this improved process a hide or
skin may be tanned in ten days as completely as it would require ten months
to perform by the usual method.
And in further compliance with the said proviso, I, the said William Drake,
do hereby describe the manner in which my said Invention is to be performed
by the following description thereof, reference being had to the Drawing
annexed, and to the figures and letters marked thereon, that is to say :-
The skins or hides intended to be tanned, after undergoing the usual and
well-known mode of preparation by liming and other processes, are immersed
in a backward or weak tan liquor. By frequent and continued handling whilst
in this state, they become saturated with liquor, and receive their preparatory
coloring before their intended submission to the improved process. The skin or
bide, being thus cleansed or otherwise prepared, is to be carefully examined,
and should any holes be found in it, they are to be sown up or otherwise
stopped by means well known, in order to prevent the liquor with which they
are intended to be filled from escaping, except through the pores of the hide
or skin. Should it be intended to tan the hides or skins as butts, middlings,
or in any other shape than the natural one, the shape which it is intended they
shall assume when tanned must be given them at this part of the process by
rounding or cutting off the extraneous parts.
DESCRIPTION OF THE DRAWING.
Figure 1 represents two hides so prepared as aforesaid, undergoing my
improved process of tanning; for I find the most economical plan is to perform
the operation upon two hides at once. Having procured two hides as nearly
of the same size and shape as possible, in order to avoid waste, and having
prepared them as aforesaid, I place them grain to grain, and sew their
corresponding edges firmly together all round with shoemakers waxed thread,
so as to form a bag sufficiently tight to hold tan liquor, in the same manner as
used formerly to be practised when the plan of churning skins made into bags
and filled with tan liquor was adopted. This bag. I hang, by means of loops
sewed on to the shoulder end of it, upon pegs S, S, S, S, resting on the bar A,
as will be better shewn in the other Figures herein-after explained: This bar
A, which I call the head rail, it will be seen forms the upper part of the
wooden-barred rack A, B, C, and at the other side of the hides is a similar

page_text: barred rack. The bag, formed of the two hides as aforesaid, being suspended
in manner here shown, between these two barred racks, the racks are drawn
together by the screws E, E, E, E, E, E, sufficiently near to each other to
prevent the bag when filled with liquor from distending, and thus being
stretched out of its proper shape. I should state, that about an inch of the
bag should be left unsewed at the upper or shoulder end, for the purpose of
introducing the funnel or tun dish D, which should always be kept cool, in
order to fill the bag with the cold tan liquor, and it will perhaps be found more
convenient to introduce the small collar or ferrel shown at Figure 2 into this
hole, and sew the edges close up to it in the first instance, to facilitate the use
of the funnell.
Figure 3 is a side view in section of the barred racks, with the bag made, as
aforesaid, of two hides, suspended between them upon the pegs, one of which
is here shown colored pink, and marked S. These pegs, it will be seen, merely
rest across the top or head rails of the barred racks. It is only necessary with
reference to these barred racks further to state, that the inner part of the bars
should be cut to an edge, and that they should all be hollowed out a little, as
shown in Figure 4, except the three or four outer bars on each side, which
may be straight, for the hides are thicker in that part technically called
the pins than elsewhere, and therefore require this accommodation, the bag
being so suspended and the barred racks screwed up as aforesaid. A funnel
or tun dish should be applied to the collar or hole in the upper edge or
shoulder end of the bag, and cold tan liquor poured in till the bag is full.
After the expiration of an uncertain time, which varies according as the hides
are more or less pervious, it will be observed that their external parts will
become moist and damp, and the moisture which escapes through the pores of
the hides will run down and drop at the lowest point of the hides, and will run
off into the gutter H (shewn in Figure 1), which should conduct it into some
suitable vessel acting the part of a refrigerator, whence it may be again poured
when cold into the bag, to supply the deficiency occasioned by this oozing out,
for it should be stated that the bag should be kept constantly full of cold liquor
by fresh supplies through the funnel, as occasion may require. When the
hides are observed to feel hard and firm, and every part of them appears
equally damp and wet, the air of the tanning apartment in which the hides are
operated upon, and which should be furnished with good ventilation, to allow
the vapour to escape, is to be heated by any artificial means known to a
temperature gradually increasing from 70 to 150 degrees of Farenheits. This
heat is to be maintained until the hides become firmer and harder in all parts,
and when they begin to assume in different parts a blackness of appearance,

page_text: and the tan liquor in the bag exhibits little progressive diminution in quantity,
and the hides are found to be tanned, the liquor is to be let off from the bag
by opening a small aperture in the stitches at the bottom or butt end of the bag,
which, when emptied, is to be removed from the racks, and the outer edges of
the hides or skins, so far as they were sewn together, are to be pared off or
rounded, and then they are to be dried and finished in the usual way. Par-
ticular care must be taken during the time the hides are inclosed between the
racks that they be at different times moved or shifted a little to the right or
left from the position in which they are at first placed, in order that the liquor and
heated atmosphere may operate on all parts alike; and as it will be seen that the
inner edges of the bars of the racks will have corresponding indentations in the
exterior surface of the hides, the shifting of or varying the positions of the hides
will be found to have a very useful effect in preventing the indentations from
being so fixedly imprinted as to render them incapable of obliteration. The
time required to finish this process, from the time the hides or skins are hung
up or inclosed between the racks, will vary according to the thickness of the
hides or skins, the strength of the liquor used, and the attention paid to the
management of the heat, and the shifting of the hides between the bars,
together with the other general management which any practitioner of ordinary
skill in the art of tanning will easily understand.
Figure 5 represents a sectional plan of the barred racks, B, B, being the
bottom rails, and the parts marked c the bars, which, it will be seen, are not
placed exactly opposite to each other, but occupy alternate spaces.
Now whereas I do not claim as my Invention the sewing of the hides into
bags, nor the filling of them with tan liquor. But whereas I do claim as.
my Invention,-
First (as regards the process), tanning by causing evaporation to take place
by means of artificial heat on one side of the hide while tanning liquor is
supplied to the other side of it, as herein-before described; and,
Secondly (as regards the apparatus necessary to carry this process into
operation), the bars acting upon the surface of the hides, in manner herein-
before described and shown in the Drawing hereunto annexed.
And such my Invention being, to the best of my knowledge and belief,
entirely new, and never before used in that part of His said Majesty's United
Kingdom of Great Britain and Ireland called England, His said Dominion of
Wales, or Town of Berwick-upon-Tweed, I do hereby declare this to be my
Specification of the same, and that I do verily believe this my said Specifica-
tion doth comply in all respects, fully and without reserve or disguise, with the
said proviso in the said herein-before in part recited Letters Patent contained.

page_text: Inrolled the Seventh day of April, in the year of our Lord One thousand
eight hundred and thirty-two.