IMPROVEMENTS IN TANNING SKINS AND HIDES
Year: 1874

page_text: LETTERS PATENT to Joseph Lambert De Montoison, of Thurloc
Square, London, for the Invention of "IMPROVEMENTS IN TANNING
SKINS AND HIDES."
Scaled the 8th June 1875, and dated the 11th December 1874.
PROVISIONAL SPECIFICATION left by the said Joseph Lambert De
Montoison at the Office of the Commissioners of Patents, with his
Petition, on the 11th December 1874.
I, JOSEPH LAMBERT DE MONTOISON, of Thurloc Square, London, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
TANNING SKINS AND HIDES," to be as follows:-
. After separating the hair or wool from the skins or hides in the usual way
or by the process or processes described in the Specification of a Patent
granted to me for separating the hair or wool from fresh or dry skins, and
preserving the hair or wool in its natural state as if cut from a live
animal, numbered 2746, August 8th 1874, and scaled October 30th 1874,
the skins are fleshed and scoured, then washed in water saturated with

page_text: lime for the purpose of neutralising the remaining alkali in the skins,
which are then washed with clean water and placed in a vessel containing
chloride of sodium, sulphuric acid, and sulphate of aluminum; or I may
employ other acids and other chlorides to neutralise the lime, the skins
are then passed through a bath or baths of warm water and soap, washed
again, and placed in or passed through a bath of tungstate of soda, then
in a bath of carbonate of soda; the fibrine of the skin will be thoroughly
tanned by such processes and be left perfectly white ready to send where
required in a fresh state, or they may be dried for immediate use. But
if a tanning by acid is wanted the skins are immediately passed through
a vessel containing tanic or other acid, and the gelatine will be quickly
tanned without injuring the fibrine as effectually and in much less time
than is required by the ordinary processes. And for the purpose of
killing the grease in the skins I proceed as follows:-Before placing the
skins in the tanic or other acid bath I place them in a bath of wood or
other spirit, which at the same time gives an odour or perfume to the
skins. In the same bath I may employ empyrometic oil which will
give an odour or perfume to the skins like Russia leather. And for the
purpose of producing light coloured tanned skins I place in the baths of
tungstato of soda and carbonate of soda zine filings before placing the
skins therein.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Joseph Lambert De Montoison in the Great Scal
Patent Office on the 11th June 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
LAMBERT DE MONTOISON, of Thurloc Square, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of December, in the year
of our Lord One thousand eight hundred and seventy-four, in the thirty-
ninth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Joseph Lambert De Montoison, Her
special license that I, the said Joseph Lambert De Montoison, my
executors, administrators, and assigns, or such others as I; the said
Joseph Lambert De Montoison, my executors, administrators, and
•

page_text: 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 "IMPROVEMENTS IN TANNING SKINS
AND HIDES," upon the condition (amongst others) that I, the said Joseph
Lambert De Montoison, by an instrument in writing under my hand
and seal, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same is 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 Joseph Lambert De Montoison, do
hereby declare the nature of the 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:-
My Invention relates to the manufacture of leather from skins or
hides herein-after termed skins, and has for one of its objects to expedite
and facilitate such operations.
My said Invention is applicable in the treatment of skins from which
the wool, fur, or hair has been separated by ordinary means, or in the
treatment of the skins which have been subjected to the improved
depilatory process for which Her Majesty's Royal Letters Patent bearing
date the Eighth of August in the year last ended, and numbered 2746,
have been granted to me.
According to my present Invention I first subject the skins after they
have been fleshed and scoured in the ordinary or in a suitable manner
to a washing in lime water. Skins or hides which have been subjected
to my process previously patented as aforesaid should be immersed in
water for about twenty-four hours previously to the fleshing and scouring
processes. They are then washed or rinsed in water and are placed in a
vessel or cistern containing acidulated water, and are then transferred
successively to vessels or cisterns containing solutions of chloride of
sodium and of alum, or the skins may be treated with a single bath
3 containing acid and the said two salts.
Various chlorides and alums derived from various bases might be
employed, but chloride of sodium and ordinary commerical alum being

page_text: comparatively cheap are very suitable. The skins are then treated in a
warm solution of soap, and are again rinsed in water to remove the
excess of soap. The skins are then treated in a bath of tungstate of
soda followed by a bath of carbonate of soda or in a bath containing both
salts. If the goods are required to be light in colour I add metallić zinc
to the solution or solutions of tungstate and carbonate of soda. If it be
required to extract the oil or grease remaining in the skins I remove the
same by pressure or by treatment with a solvent spirit, such for example
as wood, naptha, or by both means. If it be desired to impart an odour
to the skins or leather, as in the case of "Russia leather" I add a
suitable oil or matter to the said spirit. This treatment may be made
to precede the immersion in the solution of tungstate of soda if
preferred.
For some purposes or if preferred the skins treated as aforesaid may
be subsequently treated with tannic acid. The proportions and strengths
of the agents employed and the duration of the treatment will vary
according to the nature and thickness of the skins and to the degree of
effect required. By way of example when treating thin skins, such as
those of sheep, lambs, goats, kids, and rabbits, after agitating the skins in
a saturated aqueous solution of lime until any alkali remaining in the
skins is neutralised, I wash the skins in water containing about six per
cent. by weight of sulphuric acid of ordinary commercial strength. The
skins are then immersed in an aqueous solution containing about twenty
per cent. of chloride of sodium and are moved about therein for a few
minutes. The skins are next.agitated for a few minutes in a solution of
alum containing about four per cent. of ordinary commercial alum.
The skins are then immersed in water having a temperature of about
thirty degrees centigrade and containing about ten per cent. of soap in
solution. The skins are moved about and agitated in the saponaceous
solution for such a period as may be considered sufficient or until the
soap has been absorbed by the skins. The skins are then well washed
and rinsed in water and are immersed in a solution of tungstate of soda
marking about six degrees "Twaddell."
If a leather of light colour be required zinc filings or zinc in small
pieces or particles amounting to about four per cent. of the solution
reckoning by weight is added to the solution. The skins are agitated in
the solution for a few minutes, say for example ten minutes, and are
then transferred to a solution of carbonate of soda. The strength of this

page_text: solution may vary to some extent, but I prefer to use a saturated or
nearly saturated solution. The skins are agitated in the solution for a
few minutes as in the case of the treatment with tungstate of soda, zinc
being also present if desired. I may employ a single bath containing both
the tungstate of soda and carbonate of soda, in which case I prefer to
prepare a solution of tungstate of soda of the strength indicated, and to
saturate such solution with carbonate of soda. If it be desirable to
discharge the oil or grease or a portion thereof from the skins, they may
now be subjected to hydraulic pressure in the ordinary or in a suitable
manner to remove the grease or be passed between rollers, or be otherwise
treated to effect the same object. The skins may be treated with wood
naptha, potatoe, or corn, or other spirit diluted with water, say for
example, to a strength of about forty degrees centigrade, this treatment
either following the operation of pressing or being substituted therefor
as preferred. To impart an odour to the skins I add a suitable quantity
of "birch oil" or of any other known or suitable oil substance or material
which will have the desired effect. For some uses the oil or grease may
remain in the leather in which case the processes for the extraction of
the said oil or grease would-be dispensed with. After the treatment
with the bath or baths of tungstate and carbonate of soda, the skins will
have been converted into leather, the fibrine and gelatine being preserved
more completely than by ordinary processes, and if the zinc have been
employed the said leather will be white or nearly so.
For some purposes it may be necessary or advisable to subject the
skins to a further treatment in order to tan them more completely; in
which case I immerse the said skins in a bath containing tannic acid, as
for example, in an infusion of bark, sumach, catechu, or other well
known astringent, or I may treat the said skins with the " foots'
remaining from the operation of refining oil. The duration of this part
of the treatment will vary according as it may be required to tan the
skins partially or completely.
د,
For thin skins such as herein-before indicated the duration of the
treatment may be about twenty minutes, thicker skins remaining under
treatment for a longer time. The thicker skins will also require to be
treated for a longer time than herein-before indicated in the previous
stages of the complete process, the periods of time stated having only
been furnished for the guidance of the operator, and although a few
minutes treatment in some of the stages is sufficient for thin skins I

page_text: must not be understood to mean that the skins may not remain in the
liquors for a longer period within reasonable limits, if it be not con-
venient to remove them so soon as they are ready for removal.
The leather produced in manner as herein-before indicated will be
found to have lost less weight, and to be stronger as compared with 5
leather tanned by ordinary processes.
I prefer to employ an agitator revolving within the pits, cisterns, or
vessels within which the treatment of the skins is effected.
Having now described and indicated the nature of my said Invention
and methods of carrying the same into practical effect, I would in 1
conclusion have it to be understood that I claim the process or processes
for partially or completely tanning skins or hides, or for converting
the same into leather, substantially as herein-before set forth and
indicated.
In witness whereof, I, the said Joseph Lambert De Montoison, ]
have hereunto set my hand and seal, this Ninth day of June,
in the year of our Lord One thousand eight hundred and seventy-
five.
Signed and sealed by the said
Joseph Lambert de Montoison,
in the presence of
HUGH GRANT,
J. L. DE MONTOISON. (L.S.)
Clerk to Edward K. Dutton,
Agent to the Patentee,
3, Princess Street,
Manchester.