AN IMPROVEMENT OR IMPROVEMENTS IN TANNING HIDES AND SKINS
Year: 1836

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HINKES Cox, of Bedminster, near 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 Fifteenth day of September, in the seventh year of His
reign, did, for Himself, His heirs and successors, give and grant unto me, the
said William Hinkes Cox, His especial licence, full power, sole privilege and
authority, that I, the said William Hinkes Cox, my exors, adñors, and
assigns, or such others as I, the said William Hinkes Cox, my exors, admors,
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 IMPROVEMENT
OR IMPROVEMENTS IN TANNING HIDES AND SKINS;" in which said Letters
Patent is contained a proviso that I, the said William Hinkes Cox, 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 His said Ma-
jesty's High Court of Chancery within six calendar months next and imme-
diately 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 Hinkes Cox, do hereby declare the nature of my Invention, and the

page_text: manner in which the same is to be performd, are fully described and
ascertained in and by the following statement thereof (that is to say):
According to the ordinary means now most generally pursued for tanning
hides and skins, the same, when they have been deprived of hair and otherwise
prepared, are submitted to a process of continued steeping in pits, till by the
operation of the tanning liquor the hides or skins (as the case may be) are con-
sidered sufficiently tanned, which is readily judged of by those conversant with
the process of tanning. This process is of long duration, taking several months
before the hides or skins are sufficiently tanned. Many processes have,
however, been proposed for quickening the operation of the tanning process.
One method was by combining two hides or skins together at their edges by
means of metallic clamps or frames, thus producing bag into which (they
being suspended) tanning liquor was filled, and thus by hydrostatic pressure
the tanning liquor was caused to press more or less, as the operator might
consider desirable, by which means the tanning liquor was caused to penetrate
quickly into the hides and skins, and produce its effects thereon; but that
process was liable to the objection that such pressure tended to distend and
separate the particles composing the hides and skins, owing to their being only
supported at the outer edges, which was prejudicial to the object to be accom-
plished, it being desirable to condense the hides and skins rather than distend
them, or any portion thereof, and this effect was still more seriously injurious
when there were weak places in the hides or skins; hence the advantages
which this Invention appeared capable of producing were not realized, and
there has since been a mode proposed for giving support to hides or skins
made into bags, such support being by means of a series of rigid bars, with
spaces between them, the bag or hides being placed between two rows of such
bars, or, as they were called, barred racks, by which means it was intended to
counteract the prejudicial strain consequent on the process last described, but
by this apparatus those parts of the hides or skins which were not actually
touching, and, consequently, unsupported by the racks or bars, were pressed
between the bars, and more or less distended, whilst those parts which were
pressed in actual contact with the bars were not so effectually acted on by the
tanning liquor; and although it was proposed from time to time to vary the
position of the skins or hides in respect to the bars, in order thereby to
equalize the tanning process, but no even effect. could be obtained, hence the
same was rendered a very imperfect process.
Now the object of my Invention is to apply to such bags (produced by the
sewing or fastening together of the edges of one or more hides or skins) a
covering of fibrous materials, which, giving support to the hides or skins on

page_text: one side when pressed, and acted on the other side by tanning liquor, also
freely permits the tanning liquor to percolate through and pass away, such
fibrous materials being sufficiently pliant or flexible, in order to accommodate
to the figure or shape of the bag of hides or skins without permitting one part
to be pressed on more than another.
The material which I prefer to use, and which I have in practice found
fully to answer, is coarse canvass, of rather an open texture, that is, wherein
the warp threads are not closely pressed one against the other, and wherin
the warp is not beaten up hard so as to press on each other, such a fabric being
at once suitable to give close and equal support to every part of a bag com-
posed of hides or skins, and also admitting of a free passage for the flowing
away of the tanning liquor after it has passed or percolated through the pores
I take a hide or skin which has been prepared in a backward ooze in order
to give it a good leather color, and bring it to a suitable condition to be fit for
stronger liquor, as is well understood, and, having sewed the outer edges
tightly together with waxed thread, leaving a small opening at one end for
the introduction of the tanning liquor, and if there are any holes, the same are
to be sewed up; and I prefer the flesh side to be inwards. The hide or skin
thus made into a bag is then to be suspended on two hooks, so as to hang
clear of the ground, which should have gutters formed therein so as to cause
the tanning liquor to flow into a pit or other receiver as it drops from the
hides or skins. The hides or skins being thus suspended, I place round the
same a covering of course canvas, in the edges of which eyelet holes are formed
for a lacing string, by which the cover may be laced closely around the bag,
and its inequality of shape accommodated in order to give equal support to all
parts. The hide or skin or bag is then to be filled with tanning liquor by a
suitable pipe or trough from a tank suitably placed for that purpose; and in
order to carry on the process with as much expedition as possible, I recom-
mend that the premises or shed or building should be conveniently arranged
for having a number of such bags hung in a row, so that one common trough
or pipe with suitable branches may be employed; and to the upper part of each
bag I apply a stopcock, which being open during the flow of tanning liquor
into the bag, permits the air to pass off. The supply pipe being fixed within
the upper part of the bag, the pressure of the tanning liquor will be as the
perpendicular height of the column of liquor, as is well understood. The stop-
cock being closed so soon as the bag is full of tauning liquor, the tanning

page_text: liquor will quickly percolate through the pores of the hides or skins, and rapidly
produce its effect thereon, which with any leakage at the joints will produce
a decreased quantity in the bag, which is to be replaced from time to time by
allowing fresh tanning liquor to flow into the bag. The time to be allowed
for completing the process of tanning will depend on the nature, thickness, and
quality of the hides or skins, and other causes, as is the case in tanning hides
and skins generally; but those engaged in the process know when the desired
result is obtained to the hides or skins; but a correct judgment of the extent
of effect produced will readily be ascertained by cutting away a small portion
of the outer surface in order to see the effect at the middle of the thickness,
the tanner will then at once be able to judge whether the hide or skin is
sufficiently tanned.
When the hides or skins appear sufficiently tanned, part
of the sewing at the lower end of the bag is to be cut to permit of the flowing
off of the tanning liquor or ooze, the wrapper or covering is to be removed,
and the hides or skins separated, and the edges thereof removed by cutting;
the hides or skins are then to be finished and dried in the usual way.
From the foregoing description it will be evident that my Invention offers
all the advantages of a quick process of tanning without the prejudicial effects
heretofore consequent on the pressure of the fluid in the hides or skins; for
every portion of the bag, whether made of one or more skins or hides, will be
equally supported by the external covering, which being of a pliant nature,
may readily be made to assume the figure of the bag sufficiently to obtain the
object desired, that of giving equal and close support to the whole surface of
the hides or skins, yet allowing the tanning liquor to flow freely away after it
has passed through the pores of such skins or hides.
Having thus described the nature of my Invention, and the manner of
carrying the same into effect, I would remark that it will be evident that
materials composed of fibres other than that above described may be employed
as the external covering and supporting of bags made of hides or skins when
undergoing the process of tanning, without departing from my Invention,
though I believe the material above described to be the best for the purpose,
I do not therefore confine myself to any particular material for the covering and
giving support to the hides or skins, and for permitting the liquor to flow
away after it has passed through the hides or skins as above described; at the
same time I would have it understood that I lay no claim to the forming of
hides or skins into bags in order to their being suspended that they may be
filled with tanning liquor, nor do I claim the giving external support thereto
when the same is perfomed by bars or rigid surfaces pressing on parts and
leaving other parts unsupported, and thus producing an unequal effect of tanning;

page_text: but what I do claim is the application of a covering or support made of fibres
which is capable of giving an even and close support to all parts of hides
or skins on one side thereof, when pressed on the other side by tanning
liquor, at the same time such cover of fibres will allow of the tanning liquor
readily flowing away through it after having passed through the pores of the
hides or skins, as above described.
In witness whereof, I, the said William Hinkes Cox, have hereunto set
my hand and seal, this Thirteenth day of March, One thousand eight
Inrolled the Fourteenth day of March, in the year of our Lord One
thousand eight hundred and thirty-seven.