IMPROVEMENTS IN REMOVING HAIRS FROM HIDES AND SKINS
Year: 1855

page_text: LETTERS PATENT to Charles Claus, of Liverpool, in the County of
Lancaster, Practical Chemist, for the Invention of "IMPROVEMENTS IN
REMOVING HAIRS FROM HIDES AND SKINS"
Sealed the 19th February 1856, and dated the 23rd August 1855.
PROVISIONAL SPECIFICATION left by the said Charles Claus at the
Office of the Commissioners of Patents, with his Petition, on the 23rd
August 1855.
I, the said CHARLES CLAUS, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN REMOVING HAIRS FROM HIDES AND SKINS" to be as follows:-
My Invention consists in the use of certain substances for unhairing hides
and skins. For that purpose I employ waste lime arising from the manu-
facture of gas; also gypsum reduced with coke or other carbonaceous sub-
stances; also a product obtained by fluxing sulphur with lime and pyrites, or
other combinations of iron and sulphur fluxed with lime.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Claus in the Great Seal Patent Office on the
23rd February 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
5 CLAUS, of Liverpool, in the County of Lancaster, Practical Chemist, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of August, in the year of our Lord

page_text: One thousand eight hundred and fifty-five, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Charles Claus, Her especial license that I, the said Charles Claus, my
executors, administrators, and assigns, or such others as I, the said Charles
Claus, 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 "IMPROVEMENTS IN
REMOVING HAIRS FROM HIDES AND SKINS," upon the condition (amongst others).
that I, the said Charles Claus, 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 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 Claus, do. hereby. declare the.
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement (that is to say) :-
My Invention consists in the use of certain substances for the depilation
of hides and skins; and I shall in the first place describe the methods of
producing them, and subsequently the mode of application.
Firstly, I flux carbonate of lime or caustic lime, under exclusion of air or
under a cover of small coal, with sulphur, in the proportion of one part of
sulphur to two, three, or four of lime; an exact proportion being immaterial;
a compound of one sulphur to one and a half or two of lime is, however, the
most economical for use. The fluxing may be executed in a suitable furnace
or in retorts:
"
Secondly, I flux pyrites, under exclusion of air or under a cover of slag, in
a suitable furnace, or in clay, brick, or iron retorts, with carbonate of lime or
caustic lime, in the proportion of one part of lime to one or two of pyrites;
but in this case it is also a mere matter of economy to adhere to that
proportion, as a greater admixture of lime does not alter the action of the
compound.
Thirdly, I reduce sulphate of lime or gypsum at a red heat with carbona-
ceous matters, as coal or coke, &c.; thus depriving it of its oxygen. I also
employ occasionally the refuse lime which has served for the purification of gas.
Those coals which are commonly used for the manufacture of gas contain
sometimes small quantities of pyrites, which, when distilled, evolve sulphureted

page_text: hydrogen; this, in passing through the purifiers' containing the lime, is
absorbed by the same, forming a compound, which, when present in sufficient
quantity in the refuse lime, may serve as a material for the depilation of
hides. Great caution, however, should be taken in the choice and in the
use of the said material, as it frequently contains substances which act very
injuriously on the gelatinous tissue of the pelt, and which become very trouble-
some in the subsequent process of tanning, by causing a shrinking of the
grain and the appearance of dark marks. In using the substances as described
above as the first; second, and third, I submit them either to a direct and
repeated lixiviation with hot water, or I allow them, after being reduced to a
coarse powder, to lay in large heaps, and exposed on all sides to atmospheric
air, whilst water in the shape of rain is kept running upon them. By the
latter treatment a partial decomposition of the substances ensues, and the pro-
ducts thereof are subsequently washed out of the same by the continual stream.
of water; the liquid obtained by such operation is collected in suitable tanks
as it runs out of the heaps, and may then be used for unhairing, in the manner
hereafter. to be described.
.
.
In using the substance mentioned as the fourth, I dissolve the active or
depilating part of the said substance, leaving the remainder as refuse, and
also separate from tlie obtained solution all products of the distillation of coals,
such as creosote, empyreumatic oils, &c., which are very injurious to leather.
Formerly, when milk of lime was used for the purification of gas, the same.
might have been employed after it had served such purpose for depilating
hides and skins, by merely plastering it on the hair side, but as dry slacked.
lime is now generally employed this procedure cannot be adopted. The mode
in which I proceed to obtain the unhairing solution from the said substance
is as follows: I put a certain quantity of the same in its fresh state into a
suitable tank or vessel, pour boiling water upon it, and keep it hot by a steam
pipe. As soon as the liquor has reached a sufficient concentration, it is run off,
and when cool is ready for use: This operation is repeated as often as useful
liquor is obtained from it, which, is easily ascertained by a small trial with a
piece of skin. The solution might also be made, with cold water; but the
advantage I obtain by using hot water is that, a more concentrated liquid is
procured, and free from the greater part of the empyreumatic impurities; the
remaining part may be skinned or run off the top of the liquid. Besides the
presence of these empyreumatic bodies- in gas lime; other circumstances are
frequently against its use, and make the application of the substances named
as the first, second, and third, preferable, for there is occasionally a total absence
of the active unhairing compound in the lime of the purifier. In order to

page_text: unhair hides and skins in the solutions of the substances named under one,
two, three, and four, and prepared in the manner above described, I plunge
the same into pits filled with the said solutions, until the hair comes off freely,
which can be effected in a few hours. The hair becomes partly destroyed by
the action of the liquor, and the pelt is rendered beautifully soft. The mode
of plunging the hides in this way is particularly applicable for dried goods,
which are brought by it into their natural softness. For fresh or salted hides,
or such in which the preservation of the hair is a consideration, I proceed as
follows:-I prepare a paste by mixing any of the above-named solutions of
plaster of paris, or with any suitable substance which in itself would have no
injurious action on the pelt. The plaster of paris or such other substance is
quite neutral as regards the epilating action; it merely serves as a vehicle
for any of the above named solutions; for that reason a coarse thick cloth,
saturated with any of the said solutions, would answer the same purpose. This
paste, or any other vehicle of the unhairing solutions, is then laid in a thin
film on to the flesh side of the hide or skin, in the same way as has been prac-
tised before with milk of lime and other substances for sheep skins. After
this treatment I put the so prepared hides or skins, flesh side to flesh side, in
pile of not more than six or eight in number, in order to prevent by piling
up too many the possibility of an injurious sweating. After they have been
laying for one or two days in that manner, the hair will come off easily, and
as it is left in its natural state is applicable for many purposes. The liquor
passing through the hide loosens the epidermis along with the hair, and
produces thus a beautiful clean grain.
a
Having thus described and ascertained the nature of my said Invention,
and the manner in which the same is to be performed, I desire it to be under-
stood, although I have in the foregoing description mentioned certain propor-
tions of the materials employed, I do not confine myself thereto; that which
I claim being the employment of substances obtained substantially as herein-
before described for the purpose above set forth.
In witness whereof, I, the said Charles Claus, have hereunto set my
hand and seal, this Twenty-second day of February, in the year of
our Lord One thousand eight hundred and fifty-six.
CHARLES CLAUS. (L.S.)