NEW MEANS AND PROCESSES OF TANNING HIDES AND SKINSHICH A GRADUATED IMPERMEABILITY OF LEATHERS IS OBTAINED
Year: 1860

page_text: LETTERS PATENT to Gilbert Lucien Pierre Coopman, Merchant, and
President of the Commercial Court at Constantine, (Algéria,) for the
Invention of "NEW MEANS AND PROCESSES OF TANNING HIDES AND SKINS, BY
Sealed the 1st March 1861, and dated the 11th September 1860.
PROVISIONAL SPECIFICATION left by the said Gilbert Lucien Pierre
Coopman at the Office of the Commissioners of Patents, with his
Petition, on the 11th September 1860.
I, GILBERT LUCIEN PIERRE COOPMAN, Merchant, and President of the
Commercial Court at Constantine (Algéria), do hereby declare the nature of
the said Invention for "NEW MEANS AND PROCESSES OF TANNING HIDES AND
SKINS BY WHICH A GRADUATED IMPERMEABILITY OF LEATHERS IS OBTAINED," to be
as follows:-
My Invention relates to the use of the sea onion or sea squill for tanning
purposes, which contains about 35% of tanning matter, and about 30% of
gummy or fatty matters. I use in tanning instead of the ordinary bark tan the
skins or coats of the sea squill, the outer thin coats which are dry, & of a red
tint containing the greatest amount of tannin and colouring matter. The next
inner coats are thicker, and contain a certain quantity of tannin, but they lose
considerably in weight in drying. The middle layers or coats are white and
glutinous, and contain a gummy matter, which being an irritant prevents the

page_text: too rapid combination of the tannin with the skin, and thus prevents the
leather from burning. This gummy or mucilaginous matter, in consequence
of the unctuous or fatty matters it also contains, renders the hide impervious
on its application thereto. By thus stripping or separating the bulb of the sea
squill I am enabled, by using a large quantity of the outer skins, to effect the
tanning operation with great rapidity, while if I would proceed by a slower
process, I mix the outer coats with intermediate ones, and further, to
render leather impervious I moderate the action of the tannin, and at the
same time to act as an irritant on the hide I employ the white glutinous
layers containing the fatty and gummy matters. For this purpose the pro-
portions of the tanning matters are arranged accordingly as it is required to
effect the tanning with more or less rapidity, or to render the leather more or
less impervious. The leather is thus specially prepared and tanned as usual,
according to the various purposes required; for instance, shoe leather for
summer wear should be well tanned, and but slightly impervious, and leather
for winter wear to repel the damp should be well tanned and completely
impervious.
The application of the tanning matters is regulated according to require-
ments in such manner that the impermeability may be obtained during the
tanning process, which the fatty layers of the squill contribute in effecting.
The squill further contains besides the large quantity of tanning, both acid
coloring matters and saccharine matters, which greatly assist in hastening the
tanning process, but which acids would be liable to burn the leather were their
action not regulated by the fatty and gummy matter also contained. These
various combinations constitute the superiority of the squill as a tanning
agent, as they permit of the action of the tanning being moderated when too
strong, and at the same time accelerating the tanning process & increasing
the suppleness and impermeability of the leather as required.
By my process I am enabled to tan calves skins in 20 days, ordinary skins in
45 days, and obtain large hides in about 3 months. When the tanning of the
leather is nearly completed I subject it to a treatment with the ordinary tan.
The splitting or separation of the bulbs of the sea squill may be effected either
by hand or by means of a root cutter, which reduces them to strips more or
less fine, and then reduce them to a powder by means of a crusher. I use the
layers of the squill either whole or subdivided in a raw state, and then reduce
them into pulp by means of a press; I also employ these parts of the squill
either whole or subdivided, after having dried them in the sun in a dry place
suitably prepared for the purpose, or by drying them (always cut up into strips)
in a stove at a moderate heat, care being taken to preserve them in either case

page_text: from damp of the ground or atmosphere, and having reduced them to powder,.
I use them instead of bark; I also obtain tanning juices from these layers
by means of ordinary processes for obtaining such concentration.
My improved process does not interfere with the washing and vatting opera-
tions, but care should be taken that the skins do not contain the smallest
quantity of lime, and that the tanning operations be effected partly under
I effect the tanning generally in wooden vats, and resort to agitation
by suitable means.
First method. By preparing the juices either by infusion or decoction, com-
prising six operations, with a finishing process.
Second method. Tanning by means of tan in powder made from the layers.
of the squill, dry, either mixed or separate, six operations comprising the
finishing process.
Third method. Tanning either by employing the layers of the squill fresh or
dried, either mixed or separate, by means of a more or less continuous fulling
operation.
Currying. Before the leather is completely dried they are dipped, and after-
wards treated as in ordinary; care should especially be taken that the drying
of the leather be effected under cover in summer, and the same accompanied
with a slight heat in winter.
When the leather emits a slight acid odour, like that of a cider vat, it may
be certain that the leather is equally dried, it being always necessary that it
reach that state before being used.
Leather may thus be obtained of great suppleness, never cracking, nor
pervious to damp or strong heat, & not susceptible of breaking; it may also-bé
cleaned with a sponge and water, and further, does not require greasing.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Gilbert Lucien Pierre Coopman, in the Great Seal Patent
Office on the 9th March 1861..
TO ALL TO WHOM THESE. PRESENTS SHALL COME, I, GILBERT
LUCIEN PIERRE COOPMAN, Merchant, and President of the Commercial Court
at Constantine (Algeria), send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of September, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-fourth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the

page_text: said Gilbert Lucien Pierre Coopman, Her special licence that I, the said
Gilbert Lucien Pierre Coopman, my executors, administrators, and assigns,
or such others as I, the said Gilbert Lucien Pierre Coopman, my executors,
administrators, and assigns, should at any time agree with, and no others, from
time to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain. and Ireland, the Channel Islands, and Isle of
Man, an Invention for "NEW MEANS AND PROCESSES OF TANNING HIDES AND
SKINS, BY WHICH A GRADUATED IMPERMEABILITY OF LEATHERS IS OBTAINED," upon
the condition (amongst others) that I, the said Gilbert Lucien Pierre
Coopman, my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, should particularly describe
and ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said Gilbert Lucien Pierre Coopman, do
hereby declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement :-
My Invention relates to the use of the sea onion or sea squill for tanning
purposes, which contains about 35 per cent. of tanning matter, and about 30
per cent. of gummy or fatty matter. I use in tanning instead of the ordinary
bark tan the skins or coats of the sea squill, the outer thin coats, which are
dry and of a red tint, containing the greatest amount of tannin and coloring
matter. The next inner coats are thicker, and contain a certain quantity of
tannin, but they lose considerably in weight in drying. The middle layers or
coats are white and glutinous, and contain a gummy matter, which, being an
irritant, prevents the two rapid combination of the tannin with the skin, and
thus prevents the leather from burning. This gummy or mucilaginous matter
in consequence of the unctious or fatty matter it also contains, renders the
hide impervious on its application thereto. By thus stripping or separating
the bulb of the sea squill, I am enabled, by using a large quantity of the outer
skins, to effect the tanning operation with great rapidity, while, if I would
proceed by a slower process, I mix the outer coats with intermediate ones, and
further to render leather impervious, moderate the action of the tannin, and at
the same time to act as an irritant on the bide, I employ the white glutinous
layers containing the fatty and gummy matters; for this purpose, the proportions
of the tanning matters are arranged accordingly as it is required to effect the

page_text: tanning with more or less rapidity, or to render the leather more or less
impervious. The leather is thus specially prepared and tanned as usual,
according to the various purposes required; for instance, shoe leather for
summer wear should be well tanned and but slightly impervious, and leather
for winter wear, to repel the damp, should be well tanned, and completely
impervious.
The application of the tanning matters is regulated according to require-
ments in such manner that the impermeability may be obtained during the
tanning process, which the fatty layers of the squill contribute in effecting. The
squill further contains, besides the large quantity of tannin, both acid coloring
matters and saccharine matters, which greatly assist in hastening the tanning
process, but which acids would be liable to turn the leather were their action
not regulated by the fatty and gummy matter also contained. These various
combinations constitute the superiority of the squill as a tanning agent, as they
permit of the action of the tanning being moderated when too strong, and at
same time accelerating the tanning process, and increasing the suppleness and
impermeability of the leather, as required.
By my process I am enabled to tan calves' skins in twenty days, ordinary
skins in forty-five days, and obtain large hides in about three months. When
the tanning of the leather is nearly completed, I subject it to a treatment with
the ordinary tan. The splitting or separation of the bulbs of the sea squill
may be effected either by hand or by means of a root cutter, which reduces
them to strips more or less fine, and then reduces them to powder by means
of a crusher. I use the layers of the squill either whole or subdivided after
having dried them in the sun in a dry place suitably prepared for the purpose,
only drying them (always cut up into strips) in a stove at a moderate heat,
care being taken to preserve them in either from damp of the ground or
atmosphere, and having reduced them to powder, I use them instead of bark.
I also obtain tanning juices from these layers by means of ordinary processes
for obtaining such concentration. My improved process does not interfere with
the washing and vatting operations, but care should be taken that the skins
do not contain the smallest quantity of lime, and that the tanning operations
be effected partly under cover. I effect the tanning generally in wooden vats,
and resort to agitation by suitable means.
First method. By preparing the juices either by infusion or decoction,
comprising six operations, with finishing process.
Second method. Tanning by means of tan in powder, made from the layers
of the squill, dry, either mixed or separate, six operations, comprising the
finishing process.

page_text: Third method. Tanning either by employing the layers of the squill fresh.
or dried, either mixed or separate, by means of a more or less continuous
fulling operation.
Currying. Before the leathers are completely dried, they are dipped and
afterwards treated as usual; care should be taken especially that the drying of
the leather be effected under cover in summer, and the same accompanied
with a slight heat in winter. When the leather emits a slight acid odour like
that of a cider vat it may be certain that the leather is equally dried, it being
necessary always to finish the drying by hand work. Leather may thus be
obtained of great suppleness, never cracking, nor pervious to damp or strong
heat, and not susceptible of breaking; it may also be cleaned with a sponge
and water, and, further, does not require greasing.
My said process consists, as already said, in the use of the sea squill for
tanning purposes as a substitute for tan, but this substance is not a mere
substitution, for the sea squill does not contain only acid astringent tanning
matters, but it also contains gummy mucilaginous substances, which hasten
the distension, render the leather impervious, and by their being combined
with each other, constitute a superior tanning.
The first or outside coats are, as already said, thinner, red, dry, and contain
a greater amount of tannin and coloring matters, while the next or middle
ones, being white, glutinous, will chiefly contain a gummy mucilaginous irritant
matter, which produces a notable distension of the hides & skins.
Now, so much having been said, and the separation of the squill in several
parts being effected as described, the distension of the hides is to be obtained
to tanning for opening the pores and allowing of the introduction of the
tannin. There is but little, very little, difference with the ordinary river work,
care is only to be taken that the hides and skins be well deprived of lime.
The distension of the hides and skins effected by the river work is obtained
by their being dipped into juices prepared twenty-four hours at least in
advance; such juices are to be very thick, and contain the coats, which is
preferable, so as to constitute together a sort of pulp, into which the hides and
skins are to be immersed completely, and be as much as possible insulated
from the contact of the air.
When fresh squills are used a greater or lesser amount of white glutinous
gummy coats is of no great consequence, the distension will ever be great
enough, but when dry coats are employed it is more proper to make use of the
intermediate ones in a larger proportion, say, three-quarters. This being done,
and the hides and skins being thus immersed, it is proper that they should be
moved and turned about for two hours in the morning, and so much in the

page_text: evening until the grain is formed; but this last operation is not of absolute
necessity. After a number of days the hides grow distended and the juices
frothed; they must be left in this state till the coats are somewhat rotten
spungious, till they have yielded up their force and the juices froth no longer;
at that time a sort of redoing takes place, which must be carefully looked to
so as to prevent all lowering or sinking in the distending work. This operation
is to last a fortnight or more, and as soon as the coats look, as it were,
exhausted, and the hides and skins are keeping still, the coats are to be thrown
away and replaced by dry or fresh ones, but chiefly among the first or outside
coats, and such as are more red, thin, dry, and contain more tannin. The
hides and skins should be immersed completely into the pulp, turned about for
nearly two hours in the morning and so much in the evening, or even more.
They may be also turned upside-down, the chief point being, since a con-
siderable distension is obtained, to cause the tannin to penetrate the hides.
When the leathers thrive well then no turning is required. After eight or ten
days of such immersion, if any diminution were remarked in the distending
progress, it would be necessary to use a certain quantity of glutinous middle
coats, and the distension soon goes on again, and then first and second coats
or layers are again to be made use of. In this manner will the operations
continue every ten days, about until the tanning is completed and the leather
formed, the distension being obtained chiefly by glutinous layers, and the main
tanning by the use of the first coats. This multiplicity of operations varies.
according to the bulk and the quality of the leathers, and it will suffice to keep
constantly by means of a hydrometer the juice or pulp one degree higher at
least than the leather in each operation. The better reduced into a pulp the
coats are the more efficiently they will be acted upon. By so operating forty-
five days are scarcely requisite for tanning hides, being from twenty-four to
thirty pounds in weight. The pulpy juice is not to be changed unless under-
going decomposition; its form is only to be increased in proportion as the
tannin progresses, both tanning and drying begin to take place in the shade
or under cover. As the gummy mucilaginous matters are mostly yielding
imperviousness, more or less glutinous or middle coats shall be used in pro-
portion as it may be desired to obtain more or less impervious leathers, and
although the tanning work be not done quite so speedily, yet a considerable
weight shall be obtained. When it is desired to accomplish speedy work,
then a greater amount of the first coats is to be employed. As soon as it
appears evident that the tanning work is half done, then I may apply some
tan, some common bark from Aleppo firs or oak, &c., in conjunction with the
first coats, and whereby a considerable weight is also obtained; this I call the

page_text: redoing. It is fit also that after the second operation has taken place a
certain proportion of potash should be used, which proportion is not to exceed
a tenth when applied in conjunction with dry squills, nor go beyond a
twentieth when applied in conjunction with viscous ones. When the hides
are tanned it is proper they should abide for a time in tepid water, and when
the leathers are dripped the fibres are to be broken or crushed, either by
fulling or otherwise. In currying the leathers are to be dipped before they
are quite dried, and the drying should be completed by hand work and at a
soft temperature. This method of tanning, and also of currying, will admit of
all ordinary makings or hand work. The mucilaginous layers, mixed with the
first coats in unequal proportions, or used alternately according to require-
ments of hide and skin, do constitute, as before alluded to, the groundwork of
my system.
Having thus described the nature of my Invention, and the manner in which
the same is to be carried into effect, I wish it to be distinctly understood that
I do not confine myself to the precise details herein described, as such may be
varied or modified without departing from the principle of action thereof; but
I claim as being new and of my Invention.
First, tanning hides and skins of all sorts and description, by the use of the
sea onion or sea squill as a substitute for tannin and others.
Secondly, the various preparations of the tanning matter and of the hides
and skins, substantially as and for the purposes herein specified.
In witness whereof, I, the said Gilbert Lucien Pierre Coopman, have
hereunto set my hand and seal, this Fourth day of March, in the year
of our Lord One thousand eight hundred and sixty-one.
G. L. P. COOPMAN. (L.S.)