AN IMPROVED PROCESS OF TANNING HIDES AND SKINS
Year: 1872

page_text: LETTERS PATENT to Charles de Sainte Marie, of Port Ste. Marie, in
the Departement of Lot-et-Garonne (France), Doctor, for the In-
vention of "AN IMPROVED PROCESS OF TANNING HIDES AND SKINS."
Sealed the 6th May 1873, and dated the 9th November 1872.

page_text: shall be so soft and supple as to be eminently prepared for the tanning
operation, and produce superior results.
Secondly. The employment of combined solutions of sulphate of soda
and sulphate of ammonia for cleansing, preparing, and de-alkalizing
mucous, papillary, or other membranes which are capable of being used
as furred skins, or for any other purpose.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles de Sainte Marie in the Great Seal Patent
Office on the 9th May 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
DE SAINTE MARIE, of Port Ste. Maric, in the Departement of Lot-et-
Garonne (France), Doctor, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Ninth day of November, in the
year of our Lord One thousand eight hundred and seventy-two, in the
thirty-sixth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Charles de Sainte Marie,
Her special license that I, the said Charles de Sainte Marie, my
executors, administrators, and assigns, or such others as I, the said
Charles de Sainte Marie, 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 tlie United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of Man, an Invention for "AN IMPROVED PROCESS OF TANNING HIDES AND
SKINS," upon the condition (amongst others) that I, the said Charles
de Sainte Marie; 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 the said Charles de Sainte Marie, do
hereby declare the nature of the said Invention, and in what manner

page_text: the same is to be performed, to be particularly described and ascertained
in and by the following statement thereof (that is to say):-
This Invention consists,―
First. In the employment of solutions of the salts of ammonia, such as
the chloride, acetate, azotate, and oxalate, but especially the sulphate, for
the purpose of neutralizing the alkalies used for removing the hair, so
that when the hides and skins are well washed, pressed, and beaten, they
shall be so soft and supple as to be eminently prepared for the tanning
operation, and produce superior results.
Secondly. The employment of combined solutions of sulphate of soda.
and sulphate of ammonia for cleansing, preparing, and de-alkalizing
mucous, papillary, or other membranes which are capable of being used
as furred skins, or for any other purpose.
My improved processes for preparing hides and skins in general arc
especially useful for treating the bellies, stomachs, and mucous and
papillary membranes of ruminating animals, and thereby enable the
waste pieces from slaughter houses and tanneries to be profitably
used.
The improvements relate, first, to the removal of the hair; secondly,
the cleansing of the skins and membranes; thirdly, the removal of the
fleshy matters; and, fourthly, the tanning.
When the object is to take off or depilate the hair rapidly, and make
the hides and skins of superior quality, I prefer to use soda or potash,
but in general I employ lime on account of its low cost and facility of
working. After the hair is removed the next part of the process is
cleansing and de-alkalizing the hides and skins, and this operation, which
forms the essence and superiority of my Invention, has for its object the
complete separation from the hides and skins of the alkaline matters
contained in them after the removal of the hair.
The cleansing operation is effected by the immersion of the depilated
bides or skins for a greater or lesser length of time in solutions of salts
of ammonia, such as the chloride, acetate, azotate, and oxalate, but I
give the preference to the sulphate of ammonia on account, first, of its
comparative cheapness; secondly, the sufficient solubility of the com-
pound formed of sulphuric acid, ammonia, and lime; thirdly, the
softening influence of this compound on the fibres; and fourthly, the

page_text: incontestable advantage when it is used for neutralizing the effects of
potash and soda, the sulphates of which have favorable effect on the
fibres, and therefore in certain cases I mix solutions of sulphate of
ammonia and sulphate of soda together. With these conditions after a
time, varying from some hours to two or three days according to the
thickness of the hides or skins, the latter become entirely softened or
suppled after some washings and pressings, which take off the soluble and
insoluble substances or combinations of alkaline salts. Thus the remark-
able characteristic of this mode of cleansing is that the hide or skin
previously impregnated with alkali yields entirely and resembles wet
cloth or fresh skins which have had a prolonged immersion in purc
water.
The quantity of the solution of sulphate of ammonia depends upon the
quantity of lime which remains in the skin after repeated washings;
but at the outset a solution can be made by dissolving from six to eleven
pounds of sulphate of ammonia in from eight hundred to a thousand
quarts of water, but I do not limit myself to this proportion, and the
same solution can be used until the action of the sulphate ceases, or as
long as the phenomenon of the softening of the skins take place.
The fleshy substances are removed from the skins in the ordinary
manner, either after the cleansing or after the removal of the hair, and
the drying operation terminates this part of the treatment.
These operations, which can be effected in all places where hides and
skins are collected or accumulated, enable the said hides or skins to be
easily transported to or preserved in the tanneries with a certainty of
their being in the best condition, in fact, these three operations are so
distinct from tanning that they can be kept from it for the most
exacting length of time.
The mode of preparation before described can be modified in various
ways, and one plan amongst others which can be employed when treating
mucous or papillary membranes is as follows:-At the commencement
the epithelium is taken away, and, if desired, the flesh removed from the
fresh skin by means of alkalies. As in the cases before described, the
sulphate of ammonia bath is used, but it is followed or accompanied with
a bath of sulphate of soda.
The sulphates of ammonia and soda are used in the proportion of
cleven to twenty-two pounds dissolved in cight hundred to a thousand or

page_text: more quarts of water, the solutions of potash and soda having a base of
one to three per cent.
The effect of sulphate of soda is analogous to that of alum, and for the
manufacture of furred skins or peltrys it has the advantage of pre-
disposing the skins for being alumed or tanned. If the object is to alum
the goods lime ought not to be used, recourse being had to one of the
other alkalies; but if lime has been used the matters should be immersed
in solutions of sulphates of ammonia and soda. The skins or membranes
thus prepared are adapted for all ulterior operations, and particularly
that of dyeing or colouring of any required colours, thereby adapting
them for the manufacture of morocco sheaths or other articles required.
The tanning of the hides and skins is effected by the means generally
in use, but with much greater rapidity and success, inasmuch as the
tanning solutions are enabled to be more concentrated even at the com-
mencement of the process.
The preparing operations before described abridge considerably the time
required for tanning, for according to the temperature and the accessory
amelioration the skins of sheep and goats can be tanned in from three to
eight days, those of oxen or cows in from seven weeks to four months,
and the skins of calves in intermediate lengths of time.
Among the numerous advantages of my preparing process the fol-
lowing are of great importance-First, the separation or removal of the
alkali from the hides or skins is so complete that the leathers have their
most natural colour taken in connection with the tanning substances
employed; secondly, the leathers have increased solidity, strength, sup-
pleness, and condensation of their tissues, thereby establishing their
superiority; and, lastly, the quantity of the tanning matter absorbed is
increased, for on comparing the weight of the tanned skins with those
which have been cleansed and dried I have found a difference of 47 per
cent.
The steeping in alum solutions can also be easily and thoroughly
effected without requiring heat or loss of alum, and the quality of the
hides and skins leaves nothing to be desired.
It will be understood that my preparing process, founded as it is by
an entire change of proceeding, realizes to a great extent an amelioration
and benefit in all accessory details, such as diminution of pressure, the

page_text: moderation of heat, less agitation, greater concentration of liquids, and
the rich nature of the tanning substances of whatever colour they
may be.
Having thus described the nature of my Invention, I desire to be
understood that in the preparation of hides and skins comprising the
following four operations, that is to say, the removal or depilation of the
hair, the cleansing or de-alkilizing of the hides or skins, the removable of
the fleshy matters, and the tanning, I claim,-
First. The employment of the salts of ammonia, and the sulphate,
especially, for the object of effecting in the most efficacious manner the
cleansing and de-alkalization of the hides and skius previously to their
being tanned.
Secondly. The employment of sulphate of soda combined with the
sulphate of ammonia as preliminary agents for preparing furred skins or
peltrys, and especially for mucous or papillary membranes.
And thirdly. The products resulting from the application of the
treatment before described to mucous, papillary, and other membranes
for the manufacture of morocco sheaths and other articles.
In witness whereof, I, the said Charles de Sainte Marie, have here-
unto set my hand and seal, this Twenty-fifth day of April One
thousand eight hundred and seventy-three.
Witness,
CH. DE SAINTE MARIE. (L.S.)
ALBERT CAHEN,
Civil Engineer,
32, Boulevard Magenta,
at Paris.