CERTAIN IMPROVEMENTS IN TANNING
Year: 1852

page_text: LETTERS PATENT to Charles Edmond Magnant, of Paris, in the
Empire of France, and No. 69, Cornhill, London, for the Inven-
tion of " CERTAIN TYDDANNETTA "
Sealed the 16th April 1853, and dated the 14th December 1852.
PROVISIONAL SPECIFICATION left by the said Charles Edmond
Magnant at the Office of the Commissioners of Patents, with
his Petition, on the 14th December, 1852.
I, CHARLES EDMOND MAGNANT, of Paris, in the Empire of France,
and 69, Cornhill, London, do hereby declare the nature of the said
Invention for "CERTAIN IMPROVEMENTS IN TANNING" to be as follows:-
My researches and studies in chemistry have demonstrated, in
the most precise manner, that molasses have not only the property
of keeping skins in a perfect state of freshness, but still of opening all
the fibres and consequently of hastening the tanning. Acetous acids
have not only the property of drawing from the bark employed in
the tanning of skins all the tanning qualities it possesses.
I operate therefore with the aid of these two substances combined
with bark, and I obtain not only a much more quick tanning and
more perfect, but still soaking is considerably diminished, as, without

page_text: any other work than an immersion in water slightly saturated with
the above mentioned substances, I obtain the most complete extrac-
tion of the whole of the lime remaining in the skins worked by this
latter corrosive.
For the removing of the hair of the skins of oxen, I obtain this
with the aid of the same substances. Put this lime into a part of
luke warm water. This operation is a real lye. In twenty-four hours
the hair comes off with an extraordinary facility, and even during
the hardest frosts.
For the tanning of all skins for upper leather, I only give them one
powdering; then I throw over them liquor prepared beforehand in
a different pit to the one in which the skins are replaced.
For the formation of my liquor pits, I employ bark ground as
fine as possible, acetous acids in a very small quantity, and, lastly,
some molasses.
The skins of calves remain in the pits a month, those of cows or
horses six weeks or two months. During the whole time of tanning
my liquor is constantly carried from the leather pit to the liquor
pit; this continuous movement causes the extraction of the tan con-
tained in the bark to be operated more speedily, and consequently
gives more strength to the liquor. This to and fro movement given
to the liquor is done by the means of a pump.
For the tanning of the skins of oxen, I give them two powderings,
each of which last two months, and the work is the same as that
described above for upper leather.
I will further add, that the hides and skins tanned by these means
and with the substances indicated, possess all the qualities required for
commerce; that they have more weight; that the imperviousness is
greater; and that, lastly, I obtain an economy of about twenty per
cent. in the bark employed habitually. They may, besides, be sub-
mitted to all currying purposes and be employed for all usages.

page_text: SPECIFICATION in pursuance of the conditions of the Letters
Patent, filed by the said Charles Edmond Magnant in the Great
Seal Patent Office on the 14th June 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
CHARLES EDMOND MAGNANT, of the Empire of France, and No. 69,
Cornhill, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent bearing date the Fourteenth day of December, in the
year of our Lord One thousand eight hundred and fifty-two, in the
sixteenth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Charles Edmond Magnant,
Her special licence that I, the said Charles Edmond Magnant, my
executors, administrators, and assigns, or such others as I, the said
Charles Edmond Magnant, 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 "CERTAIN IMPROVEMENTS IN TANNING,"
upon the condition (amongst others) that I, the said Charles
Edmond Magnant, by an instrument in writing under my hand and
scal, 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 Charles Edmond Magnant, 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 (that is to say):
The new process in question is divided into two distinct parts: the
first comprises all the operations which the skins for soft work are
to undergo; the second, all those concerning thick leather and the
tanning of these different sorts of leather.

page_text: As by the usual processes, the skins, in coming from the slaughter
house, must be put into the water to soak, and to take away the dung
and dirt with which they are soiled; they must be left in the water
a few hours only, then thoroughly cleaned with a broom rinsed in
changing the water several times, and, as soon as they are drained
(one hour is sufficient), immediately put to peel. The preparation,
weak at first, must not contain too much lime; but the strength must
be gradually increased every twenty-four hours during the first three
days. Four or five days in the peeling tub will be sufficient to obtain
easily the coming off of the hair. The skins must be taken out once
or twice a day, during one hour, i.e., out of the peeling tub. When
they come out of the peeling tub, the skins must be well rinsed, in
order to take away the greater part of the lime, with which they
always remain imbibed; then they must be scraped, and the thick
flesh cut off only; rinsed on the wooden leg, to take away the hair
and the flesh; they must be, after this work, submitted to the bath
of complete extraction of the lime infiltrated into the fibres. This
bath must be composed of six hundred to seven hundred grammes
(1lb.) of molasses (treacle) per one hundred kilogrammes (2 cwt.)
of skins fresh from the slaughter house, or the equivalent weight in
dry skins brought back to a fresh state by the ordinary means.
It
is understood that this quantity molasses indicated must be dissolved
in two or three quarts of warm water, and added in this state to the
quantity of cold water necessary to cover the skins put into this
bath. They must be left from twenty-four to thirty-six hours, for
the action of the temperature giving the more extent to the fermen-
tation. As this temperature increases in heat, our bath acts more or
less energetically. The skins must be taken out on planks twice
during the operation; and they come out of this bath the exercised
hand of the practical man will be surprised at the softness, and the
body these skins will have taken. They must be immediately well
fleshed, or scraped; then, in rubbing them lightly with a hone, will

page_text: take away entirely the lime they might still contain. Here the
soaking work is finished. We are are now going to pass on to the
swelling out, for which request a scrupulous attention.
Swelling out of Upper Leather.
One tub is enough for this work (as much of course as the
quantity of goods worked does not exceed what the tub can hold).
We increase progressively the strength of the liquor, as will be seen
by the particulars of the operation. Let us say at once, that the
quantity of bark necessary for this work (or rather the tan) must
be the same as that usually employed. It must be divided into
three equal parts of weight. The skins finished soaking, as we have
explained, must be put into the tub, which must contain, the first
day, very weak liquor to color them, and at the same time, to avoid
a too quick taking of grain, which, on that account, would be coarse
and irregular; all things which we obtain in a remarkable perfec-
tion, and which is obtained by the malleability which we can give
our skins, in getting out of them the least atom of lime; thence also
the superiority so remarkable of the over weight which we obtain,
and the excellent quality of our produce; for, freed for ever of the
corrosive which destroys the fibre, which our good bath takes from
it, in opening all the pores, the tanning liquor penetrates, runs
abundantly and with facility by all pipes, and gives consequently
the strength, the softness, and the enormous weight which we
obtain.
The skins must be much and frequently moved the first day, in
order that they may take all over them a good and equal color; the
second day must be put into the tub a first part of the bark or tan
destined for the swelling out, and two pounds treacle per two
hundred weight of fresh skins from the butchery, or the equivalent
weight, as we have said above, and also six ounces of acetous acid
of 7°, according to the best acids. The substances which are put
into the tub must be well moved, and only poured in when the
skins are on the planks. The skins must be left in this tub
so prepared four or five days, according as the tan has lost more

page_text: or less of its strength. The first bark must be taken out with a
net, or with a bucket with a hole in the bottom for the liquor
to run out, and it must be replaced immediately by a second
part, two pounds of treacle, and six ounces of acetous acid must be
added, as in the first place; and, in leaving these skins four or five
days in this tub, this bark must equally be taken out to be replaced
by the third and last tan, to which must still be added two pounds of
treacle, and six ounces of acetous acid. After they have been five
days in the latter place, the skins will have a fine color, an equal
and well formed grain, and will have already acquired a good be-
ginning of tanning. During the swelling out the skins must be taken
up on planks morning and night, but only the time to take them
up and put them down immediately. Care must be taken only to
put into each tub skins of about the same strength; for the liquor
must be stronger or weaker, according to the strength of the skins.
The doses indicated of acid and molasses, per two hundred weight
of skins, are for strong calves skins and small cows skins. These
doses must be a little smaller for small calves skins; and conse-
quently larger for large cows skins and oxen skins for soft purposes;
small calves skins for varnishing, and which on that account are sold
by the dozen, do not require to gain in weight, may very well be
tanned in this tub; the only thing to be done for that, is to increase
a little the quantity of bark, which we have indicated in the
swelling out. In coming out of the swelling tubs, the skins may
be put to rest till there is enough to fill a pit.
Instead of heating, means generally employed for getting the hair
off oxen skins, and which we condemn, because it is the beginning
of putrifaction, which not only reduces weight, but also attacks
sometimes the grain (a skin weighing two hundred weight just
coming from the slaughter house will lose twenty-two, twenty-four,
and even twenty-six pounds, by heating, whilst by the means which

page_text: we employ it loses but the hair; the fact is easy to verify), a
wooden tub is made about two yards diameter, which tub can
hold from ten to twelve skins weighing one hundred weight each.
This tub must be placed upon two tressels high enough to be
able to put under a bucket to receive and contain a part of
liquid of the solution which we are going to indicate; which
solution will run out slowly of the tub into the bucket by the
means of a hole made at the bottom of this tub, and closed by
a peg surrounded with straw. A bath cylinder must be placed
in this bucket, to warm the liquid; or, if preferred, the water
can be warmed in a large cauldron or boiler. The liquid ne-
cessary to cover the skins must be warmed 20° at the utmost, and
must be poured upon them, in taking care to stir sufficiently for the
water to warm all the skins over, and never to seize them. This
first water, poured on with a temperature of 20°, will lose almost
instantaneously 15° by the action of the skins with which it
will find itself in contact; also it is necessary to leave it run out
pretty quickly into the bucket, to warın it again immediately, and
to come gradually to a kept up heat of 20°, but never more; in
summer, 8° to 10° are quite sufficient. We add, that if the skins
were warmed too fast, and more than we indicate, the work would
not be hastened for that, and the skins might lose their grain, and
become full of holes.
The solution must be composed of one pound of treacle for.cach
skin. This treacle must be dissolved in water, the tub shut with a
wooden lid, in the middle of which a hole having the form of a
funnel must be made to pour in the liquid with a bucket, and to
throw it constantly over the skins. It is seen that the hole made
at the bottom of the tub, and which the peg surrounded with
straw only closes imperfectly, the liquor is put back into the tub
as fast as it runs out into the bucket. The fermenting action
which the treacle produces dilates the skins, opens the pores, and
facilitates, in a degree superior to all the other means, the coming
off of the hair, which is obtained in twenty to twenty-four hours,
some times in ten to twelve. It is necessary to stir the skins up

page_text: frequently; as much, however, as their weight allows.
After
they have been in this wash six hours (for it is a real wash),
some parts will commence falling off. To obtain easily the coming
off of the hair, the work must be done when the skins are still
warm. Our sweet preparation goes through the skins, and facilitates
so well the thinning off of the hair, that the grain can never be
attacked; besides, the skins, after this operation, are as white and as
fresh as skins from cattle that have just been slaughtered. The
fleshing must be done immediately after the hair is off; then a
rub must be given, to clean the skins. The soaking operation ends
here. We avoid, as it is seen, several very expensive dressings,
giving at the same time more quality, more beauty, to the produce
frequently; as much, however, as their weight allows.
After
they have been in this wash six hours (for it is a real wash),
some parts will commence falling off. To obtain easily the coming
off of the hair, the work must be done when the skins are still
warm. Our sweet preparation goes through the skins, and facilitates
so well the thinning off of the hair, that the grain can never be
attacked; besides, the skins, after this operation, are as white and as
fresh as skins from cattle that have just been slaughtered. The
fleshing must be done immediately after the hair is off; then a
rub must be given, to clean the skins. The soaking operation ends
here. We avoid, as it is seen, several very expensive dressings,
giving at the same time more quality, more beauty, to the produce
treated by our methods.
Swelling out of Thick Skins.
Four tubs alone form our swelling out course to work alternately
thirty-two thick skins. We suppose these tubs to hold about three
hundred and thirty gallons, the skins excepted.
The first, which must hold two hundred and sixty four gallons of
pure water and twenty-two gallons of liquor (the same strength as
that generally used for this work), we put eight thick skins, which
we leave in twenty-four hours, taking care to take them up night
and m orning, and to put them in again immediately. The second
day we add in this tub twenty-two gallons of liquor, three pounds
of treacle, and one pound of acetous acid of 7°; and we leave
our skins for three days, taking them up night and morning, and
putting them down after they have been aired a few minutes, and
the liquor (or ooze) has been well stirred up. The fifth day, the
skins must be put into the
Second tub, composed of two hundred and forty gallons of pure
water, sixty-six gallons of ooze, and five pounds of treacle, and one
pound four ounces of acetous acid. They must be taken up on boards
night and morning, and put down again as soon as the liquor has
been well stirred up again. The second day they have been in this
tub, according to what we have indicated for the first swelling out.

page_text: twenty two gallons of liquor must be added. The skins must still
remain in this tub three days, but must be taken out night and
morning, and put in again as soon as the liquid has been well stirred
up. The eleventh day they must be put into the
Third tub, which must be composed of two hundred and twenty
gallons of water, eighty eight gallons of ooze, and seven pounds of
treacle, and one pound eight ounces of acetous acid. They must be
taken out on boards night and morning, and put in again as soon as
the liquid has been well stirred up. The second day they have
been in this tub twenty two gallons of liquor must be added. The
skins must still be left in this tub three days, taken out night and
morning, and then put in again when the liquid has been well
moved. The sixteenth day these skins must be passed into the
Fourth and last tub, which must contain one hundred ands eventy
six gallons of water, one hundred and thirty two gallons of ooze,
seven pounds of treacle, and one pound twelve ounces of acetous
acid. They must be taken out night and morning, and put down
after the liquid has been well moved. The second day after they
have been in this tub twenty two gallons of liquor must be added.
The skins must still remain three days in this tub, and taken out
morning and night, and put in again after the liquid has been well
moved. The second day after they have been in this tub twenty
two gallons of liquor must be added. The skins must still remain
in this tub three days, and be taken out morning and night, and
put in again as soon as the liquid has been well moved. They will
come out of this tub with a fine color, without the least grain, and
swollen out in a remarkable manner. They will not be as stiff as
skins generally are when swollen out with sulphurated acid; but
they will take their natural strength in tanning. They will still
take more strength, if left only eight days longer in the tubs, till
the number necessary to fill the pit is ready.

page_text: same tanning strength, and as some contains much, whilst others
possess less, it therefore would be impossible for us to give an exact
proportion, as it may vary greatly. The tanner will have to do
this himself, in always taking for basis, whatever might be the
quantity that he habitually uses, a saving of one fifth.
This once well understood, we therefore say, that the quantity of
bark necessary to tan a number of skins being fixed according to
this basis, must be divided into three equal parts.
The first is to prepare and to keep up to the same degree of strength
the liquor pit, by the frequent additions which we introduce of this
part of bark powder. During the tanning, the two other parts are
used for the two powderings which we give our skins; once in
putting them into the pits, the other, when we take them up to put
them down again in fresh powder.
The pits must have a double bottom; and those which have none
must have one made with boards placed upon ledges cight or ten
inches high, in order that there may be really this distance between
the firm bottom and that which supports the skins, and that so it
may be
with a pump,
easy
which will plunge into the lowest bottom
to deprive the skins of liquor, as we shall soon state. Holes must
be made in this double bottom three or four lines diameter on its
whole surface, in order to facilitate the running out of the liquor.
This bottom must be covered over with a coarse cloth, to hinder
the powder from getting through these holes into the lowest bottom.
The skins must be put down again into the pits, as they generally
are for the first powdering, and more powder must be put on the
thick and hard parts than on the thin parts. One third of the whole
of the bark mentioned above must be used for this. The pit, when
full, must be imbibed with the liquor prepared in another pit, till
the liquor covers entirely the skins. This covering can be done
easily with a hand pump, or much more savingly with a syphon.
The distance of the liquor pits from those containing the skins
will ever be a difficulty, as it is with a gutter, to send the liquor
from one pit to the other.
We will observe, that each pit, whether it contains liquor or skins,

page_text: must be provided with a chimney, by which either the pump or the
syphon will work alternatively. This chimney must be made with
two boards running from top to bottom; and several holes must be
made in the bottom part, in order for the liquid to come into it
easily.
Every other day the liquor contained in the leather pits must be
taken out with the pump (and this must be done during the whole
time of tanning), and put into the liquor pits, where it must be left
from twenty to twenty four hours, to get stronger with the bottoms
of these pits and the bark that remains in continually, and which,
on account of the substances we add, throws out totally all the tan
it contains. The liquor must be put on the skins again after the
twenty or twenty four hours are elapsed, and left on two days.
The first powder must be left on the calves skins a fortnight,
three weeks on the cows skins, and six wecks on the thick skins
(oxen, bulls, and horses). After this time is elapsed, the skins
must be taken up on the sides of the pits, and the tan thrown into
the liquor pits (always to lose nothing). Then the skins must be
put down again in the second and last powder. In using the third
part of 'powder, and in following for this second putting down the
instructions indicated for the first, as well for the pits containing
the skins as for those containing the liquor. After the skins have
been this time in the pits as long as the first, they may be taken out
and perfectly well tanned; they will have a fine color, and especially
an over weight, which can be explained, as we use neither sulphu-
rated acid nor heating; in a word, we do not fear to have them com-
pared with the best skins tanned in ten, fifteen, or eighteen months.
Preparing of the Liquor Pits.
Out of the part of bark powder with which it is intended to make
the liquor in the first place, two thirds must be put into this pit.
One pound eight ounces of treacle must be added, dissolved in a
little lukewarm water, and five ounces of acetous acid per two
hundred weight of skins in the pit. Then the quantity of water
necessary to cover the skins well must be poured on.

page_text: If the liquor required for two pits containing skins is prepared in
the same pit, it will consequently be necessary to put also in this pit
the doses indicated for the number of skins to be tanned; and to keep
this liquor an equal strength, the remaining part of the bark
must be thrown into the liquor pit by equal parts every ten days,
as well as one pound eight ounces of treacle and five ounces of
acetous acid, divided, the same as this bark, between ten and twelve
days, during the whole time of tanning. It will be therefore three
parts to make for calves skins, five for cow skins, and nine for thick
skins (oxen, bulls, and horses).
A great saving of bark cannot be expected during the first
operation; but it will be still greater than we announce in the
following; for our pit liquor, after it has been used for tanning,
will do very well for soaking out.
The dry skins called Buenos Ayres hydes, or any other foreign
skins, may be treated by our process. They must be previously
brought to a fresh state by being fulled, and not to spoil the grain,
so often attacked, inust be left in a bath of fresh water twenty-four
hours, acidulated with twenty-five drams of acetous acid per skin.
The same bath, with fifty drams per ox or cows skins, fresh from
the slaughter house, in twenty-five drams per calves skins, will
preserve them in the height of summer, during a fortnight and
more, from putrefaction.
In witness whereof, I, the said Charles Edmond Magnant, have
hereunto set my hand and seal, this Fourteenth day of June,
in the year of our Lord One thousand eight hundred and
fifty-three
CHARLES MAGNANT. (L.S.)