AN IMPROVEMENT OR IMPROVEMENTS IN THE MANUFAC- TURE OF LEATHER
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
WILKINS, late of Blue Anchor Road, Bermondsey, in the County of Surrey,
but now of No. 26, Surrey Place, Old Kent Road, in the same County,
Tanner, send greeting.
! WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at.
Westminster, the Twenty-second day of May, in the eighth year of Her reign, did,.
for Herself, Her heirs and successors, give and grant unto me, the said Edward
Wilkins. Her especial license, full power, sole privilege and authority, that I,
the said Edward Wilkins, my executors, administrators, and assigns, and such
others as I, the said Edward Wilkins, my executors, administrators, or assigns,
should at any time agree with, and no others, from time to time and at all times
during the term of years therein mentioned, should and lawfully might make,
use, exercise, and vend, within England, Wales, and the Town of Berwick-upon-
Tweed, my Invention of "AN IMPROVEMENT OR IMPROVEMENTS IN THE MANUFAC-
TURE OF LEATHER;" in which said Letters Patent is contained a proviso obliging
me, the said Edward Wilkins, by an instrument in writing under my hand and
seal, particularly to describe and ascertain, the nature of my said Invention,
and in what manner the same is to be performed, and to cause the same.
to be inrolled in Her Majesty's High Court of Chancery within six calendar
months next. and immediately after the date of the said in part recited
Letters Patent, as in, and by the same, reference being thereunto had, will
more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Edward Wilkins, do hereby declare that the nature of my said Invention, and

page_text: the manner in which the same same is to be performed, is particularly
described and ascertained in and by the following description thereof (that is
to say):-
My Improvements in the Manufacture of Leather consist,―
Firstly, in softening and preparing dried hides, kips, or other skins, pre-
viously to their being subjected to the unhairing process.
Secondly, in the improved modes of unhairing, or depriving of hair, hides,
kips, or other skins, as herein-after mentioned.
Thirdly, in the mode of impregnating hides, kips, or skins (whether tanned
or untanned), with oil, as herein-after mentioned.
Fourthly, in the mode of drying hides, kips, and skins, which have been
tanned or impregnated with oil, as herein-after described.
I will now proceed to shew the manner in which I carry my said improve-
ments respectively into effect.
And, firstly, as to my improved methods of softening hides, kips, and other
skins, and preparing them (when necessary) for the unhairing process. In pre-
paring dried skins for the unhairing process, they are usually submitted to
the action of beating stocks, but sometimes they are softened by soaking
merely, which is usually a long, tedious operation. According to my improved
method, I construct an air-tight cylinder or pit, which is furnished with
an air pump, and this cylinder or pit I heat by a steam pipe or other conve-
nient means. In the cylinder or pit I place the hides or skins, and proceed to
exhaust the air therefrom, and the more perfect the exhaustion the better
the effect. will be. When the air has been very considerably exhausted I fill
the cylinder or pit with warm water (of 80 degrees of Fahrenheit), from any
tank or vessel connected therewith. The skins after remaining a little time
(from about twenty-four to forty-eight hours) in the water will become soft
and ready for the next operation.
My said improvements in the process of unhairing, or deriving of hair,
hides, kips, or other skins, consist in the employment of lime-water, or any
other known depilatory, at the temperature of about eighty degrees of Fahren-
heit, instead of such depilatories being applied cold as hitherto; and also
consist in the use of such acid solution (whether warm or cold) and such
weak tan liquor as depilatories, as herein-after described.
I will first describe my mode of using warm lime-water for the unhairing
skins. It is well known that a cold solution of lime has been long used for
removing the hair from hides or skins, but by my improved plan a considerable
saving of time is effected, and the injury which frequently happens to the hides
from long immersion in the lime-water is altogether avoided. The mode which

page_text: I prefer for carrying this improvement into effect is as follows:-Having pre-
pared a pit of any convenient dimensions, I place within it a tank, made either
of wood, metal, or other suitable material. The tank must be supported upon
bearers or by other convenient means, and suspended from about six to twelve
inches from the bottom of the pit; the tank also must be of such a size and
so placed within the pit that there shall be a space of about twelve inches
between every side of the tank and the sides of the pit within which it is
placed. I then conduct a steam pipe (which communicates with some adja-
cent steam boiler) round the pit, and in contact with or near to the bottom of
the tank. Into the tank the lime solution is poured, and the skins are to be
placed in it, and the steam being let into the pipe already described, will raise
the temperature of the contents of the tank, and the heating ought to be
continued until a temperature of eighty degrees Fahrenheit has been obtained,
after which the steam must be diminished or turned off, and let on again
occasionally, so as to preserve a uniform temperature of about eighty degrees
Fahrenheit. This process must be kept up for about twenty-four hours, the
skins (as usual) being occasionally moved, and at the end of that time the hair
will readily come off, and the skins may then be taken out of the tank.
Instead of the peculiar construction of pit just described, an ordinary tanner's
pit may be used; and for this purpose it ought to be provided with a moveable
cover, and a coil of steam pipe for heating the lime solution by means of
steam. The application of any other warm depilatory for the purpose
of unhairing skins may be effected in the same way as herein-before de-
scribed with reference to lime-water, the tank or other vessel used being made
of a proper material, according to the nature of the depilatory which is
employed; as, if the depilatory be an acid, the vessel must be made of some
material which will resist the acid.
Another of my improvements in unhairing hides or skins consists in the
employment of a solution of either warm or cold acid made from tan
liquor, which liquor, when exposed to the air in a warm place, and fer-
mented with yeast, will become acid in from ten to twelve days. For the
purpose of applying this acid solution to the hides or other skins, I con-
struct a vessel or vessels of glazed earthenware or glass (which will resist
the action of the acid), and place therein the hides or skins; and the acid
liquor just described, if too strong (as will generally be the case) must be
diluted with water, and it will usually require about three parts of water to
one of the acid. This depilatory may be applied warm, in a similar manner
as herein-before described with reference to lime-water. While the acid is
operating upon the skins I have found that gelatine is being formed, and the
quality of the skin is improving. After hides or skins have been subjected to

page_text: either of the depilatories already mentioned for unhairing, 1 place them in an
air-tight tank or other proper vessel, and exhaust the air therefrom in the same
manner as herein-before described for the purpose of softening dried skins. I
then, by means of a force pump communicating with the tank, force warm water
into it, which, penetrating the skins, will remove the lime or acid contained
therein. The degree of pressure which I think sufficient to apply by means of
inch.
square
the force pump is about sixty pounds to the
Another of my improvements in unhairing skins consists in the employment,
as a depilatory, of weak tan liquor of about the strength of from two to three
degrees by the bark hydrometer, and this depilatory is to be used warm, and
of the temperature of about eighty degrees of Fahrenheit. And to obtain the
most advantageous effect from this depilatory I place the bides or skins in an
air-tight tank or other vessel of sufficient strength, and having exhausted the
air in the same manner as herein-before described with reference to my mode
of softening dried skins, I let in the weak tan liquor, and keep it up to a tempera-
ture of about eighty degrees Fahrenheit. During the application of any of the
depilatories herein-before described the skins are to be moved or handled
in the ordinary way. When lime-water is applied as herein-before described,
the hair may generally be removed from the skins in about thirty-six hours;
and when tan acid or weak tan liquor is used, the hair may generally be
removed after forty-eight hours' application.
My third improvement consists in impregnating hides, kips, or other skins
(whether tanned or untanned) with oil, as herein-after described (that is 'to
say), the hides or skins are placed in an air-tight tank or other vessel of suffi-
cient strength, and having an air pump and also a force pump connected
therewith. The air in the tank is then to be exhausted in manner herein-
before described, and cod or other oil is to be forced into 'the 'tank by a
pressure of about sixty pounds to the square inch, 'so that the oil may enter
the skins and expel the water or other liquid therefrom. During this opera-
tion the temperature is to be maintained by steam pipes, or any other
convenient means, at about eighty degrees Fahrenheit..
The fourth part of my improvements consists of a mode of drying hïdes,
skins, and leather. For the purpose of performing this operation I construct
an air-tight chamber or room of any required size, and of sufficient -strength,
and provide it with moveable frames, upon which I hang the hides, skins, or
leather. This air-tight chamber or room may be made of brick, stone, cast
iron, or any other suitable material as thought most desirable. It is to 'be
'furnished with a door, in order to enter the chamber and place the substances
to be dried upon the frames. When the chamber is sufficiently filled the door
is 'to be closed and the crevices made air-tight. In the upper part of the

page_text: chamber one end of a pipe provided with a stopcock is inserted; its other end
leads to an air pump or exhauster; and at one end of the chamber, near the
bottom, a steam pipe proceeding from a boiler, and having a stopcock, enters
the chamber, and after traversing the sides and further end of the chamber,
makes its exit therefrom. Having hung up the hides or leather upon the
frames, and closed the door air-tight as above explained, I proceed to exhaust
the chamber of air by means of the air pump, and also turn on steam from the
boiler into the steam pipe, so as to raise the temperature of the chamber to
about eighty degrees Fahrenheit, at which temperature, or nearly so, it ought
to be maintained. The combined action of the heat from the steam pipe and
the exhaustion of the air pump will cause vapour quickly to arise from the
hides and leather; and as the vapour rises I continue to draw it out from the
chamber by means of the air pump, until the goods contained therein are dry,
which will be readily ascertained by the practice of the workmen, or by means.
of glass fixed in the sides or ends of the chamber.
And I hereby declare that I do not claim, as essential to my Invention, the
peculiar forin or construction of any of the pits, tanks, vessels, or instruments
herein-before mentioned; and that I have only described such pits, tanks,
vessels and instruments for the purpose of describing the modes in which my
said several improvements are respectively to be performed or carried into
effect.
In witness whereof, I, the said Edward Wilkins, have hereunto set my
hand and seal, this Twenty-second day of November, One thousand