A NEW OR IMPROVED PROCESS IN UNHAIRING OR DEPILATING SKINS
Year: 1880

page_text: LETTERS PATENT to Victor Lesage, of Paris, in the Republic of France, Civil
Engineer, for an Invention of "A NEW OR IMPROVED PROCESS IN UNHAIRING OR
DEPILATING SKINS." A communication from Emile Chesnay, of 88, Boulevard
St. Marcel, Paris, in the Republic aforesaid.
PROVISIONAL SPECIFICATION left by the said Victor Lesage at the Office
of the Commissioners of Patents on the 1st November 1880.
VICTOR LESAGE, of Paris, in the Republic of France, Civil Engineer. "A NEW
OR IMPROVED PROCESS IN UNHAIRING OR DEPILATING SKINS." A communication
by Emile Chesnay, of 88, Boulevard St. Marcel, Paris, in the Republic aforesaid.
The Invention relates to a new or improved process in depilating or separating
green or dry skins from the hair or wool, and consists in plunging the skins with
the air on into a bath composed of a mixture, in weight, of from two to ten parts
of liquid ammonia of commerce, four to five parts of sulphuric acid, and one
hundred parts water, for a longer or shorter time, according to the thickness and
tenacity of the skins and the density of the mixture; or in bedaubing wool skins
on the flesh side, so as not to injure the wool, with a thick layer of the solution
concentrated, or with a paste made with the said solution and argil or any other
neutre matter suitable, after having first softened the skin, if necessary, with warm
or cold water upon the flesh side. The air or wool detaches and falls of itself,
and all that remains necessary is to expose the skins to a washing in running
water.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Victor Lesage in the Great Seal Patent Office on the 20th April
1881.
VICTOR LESAGE, of Paris, in the Republic of France, Civil Engineer. "A NEW
OR IMPROVED PROCESS IN UNHAIRING OR DEPILATING SKINS." A communication
by Emile Chesnay, of 88, Boulevard St. Marcel, Paris, in the Republic aforesaid.
The Invention relates to a new or improved process in depilating or separating
green or dry skins from the hair or wool, and consists in plunging the skins with
the hair on into a bath composed of a mixture, in weight, of from two to ten parts
of liquid ammonia of commerce, four to five parts of sulphuric acid, and one
hundred parts water, for a longer or shorter time, according to the thickness and
tenacity of the skins and the density of the mixture, or in bedaubing wool skins
on the flesh side, so as not to injure the wool, with a thick layer of the solution
concentrated, or with a paste made with the said solution and argile or any other
neutre matter suitable, after having first softened the skin, if necessary, with warm
or cold water upon the flesh side. The hair or wool detaches and falls of itself,
and all that remains necessary is to expose the skins to a washing in running
water.
The new and improved process above described is of very easy and simple
application, and the depilation, so to say, is instantaneous; besides, the skin is
soaked so as to absorb more regularly and completely the tannic matter.
Before subjecting the skins to the action of the sulphite of animonium, the dry
skins ought to be softened down. After being unhaired the skins may be tanned
according to the ordinary processes known.
The ammonia of the sulphite may be replaced by any of the derivatives of
ammonia, such as ammoniacal salts, sulphates, chlorydrates, oxalates or other
equivalents.
Hence, as it follows and may be understood by the preceding description, this
new and improved process does not present any of the inconveniences of the
processes in use to this day, of which the least was the time required.
Thus the process most generally applied is to put the skins into a lime-water
bath, which swells them and allows of removing the hair or wool with a blunt
scraping knife, but this method has the drawback of necessitating multiplied
labor and an extended time, since the treatment has to be kept up for three or four
weeks. This process has moreover for wool skins the disadvantage of moistening
the fleece, and thus cause it to lose part of its value.
Other processes based upon the use of different chemical compounds give results
but little satisfactory as to industrial applications, or seriously expose the health of
the workman, as these compounds nearly always contain sulphates of arsenic, or
sulphides and cyanides of calcium, which may, if certain precautions are neglected,
disengage prussic acid.
These matters may even produce a considerable waste upon the fleece by attacking
and corroding it wherever they touch. The barbarous method of subjecting skins to
a commencement of putrefaction, followed by a scraping, which, in spite of all
precautions, greatly damages the skins and thus interferes with the ulterior
operations of tanning.
Having thus described the nature of the said Invention and the manner of
performing the same, I would have it understood that I do not confine myself
to the precise details above enumerated, as these may obviously be modified
without departing from the principle of the Invention, but what I claim is,-
A new or improved process for depilating or separating dry or green skins from

page_text: the hair or wool, a bath of sulphite of ammonium, composed of a mixture of liquid
ammonia, sulphuric acid and water, more or less concentrated, and in the proportions
and manner substantially as above specified.
In witness whereof, I, the said Victor Lesage, have hereunto set my hand
and seal, this Twentysixth day of April, in the year of our Lord One
thousand eight hundred and eighty-one.
VICTOR LESAGE. (L.S.)