IMPROVEMENTS IN UNHAIRING AND PREPARING SKINS, AND IN TANNING
Year: 1856

page_text: LETTERS PATENT to Charles Augustus Preller, of Lant 'Street, in the
Borough of Southwark. Leather Manufacturer, for the Invention of
"IMPROVEMENTS IN UNHAIRING AND PREPARING SKINS, AND IN TANNING."-
Dale communication
"IMPROVEMENTS IN UNHAIRING AND PREPARING SKINS, AND IN TANNING."
Partly communication
PROVISIONAL SPECIFICATION left by the said Charles Augustus Preller
at the Office of the Commissioners of Patents, with his Petition, on the
27th June 1856.
☐
I CHARLES AUGUSTUS PRELLER, of Lant Street, in the Borough of Southwark,
Leather Manufacturer; do; hereby declare the nature of the said Invention for
"IMPROVEMENTS IN UNHAIRING AND, PREPARING SKINS, AND IN TANNING," (partly
communicated to me by a foreigner residing abroad), to be as follows:-:
'
This Invention consists in the employment of cod oil, horse grease, or other
fatty substances in. combination, with lime, and soda, for the purpose of un-
hairing, and for preparing for tanning or tawing, and.in the employment of cod
oil, horse grease, 'or.: other fatty substances combined with soda and the usual
materials containing tannic acid, such as oak bark, mimosa bark, terra japonica,
cutch, divi-divi, sumach, &c.," for the purpose of tanning. Warm water is

page_text: employed for making the solutions and extracts of these materials, and the
skins are agitated while immersed in the liquid, either in cylinders, having
on their inner surfaces projections or pegs, and kept rotating, or in open
vessels or pits, by manual labour, or by any other suitable means.
Instead of soda, other alkalies may be used, but always in combination with
oily or greasy matters.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Augustus Preller in the Great Seal Patent Office on
the 27th December 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
AUGUSTUS PRELLER, of Lant Street, in the Borough of Southwark, Leather
Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-seventh day of June, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Charles Augustus Preller, Her special licence that I, the said Charles
Augustus Preller, my executors, administrators, and assigns, or such others as
I, the said Charles Augustus Preller, 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 "IM-
PROVEMENTS IN UNHAIRING AND PREPARING SKINS, AND IN TANNING," partly com-
municated to me, upon the condition (amongst others) that I, the said
Charles Augustus Preller, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, 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 Augustus Preller, do hereby declare
the nature of the 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 thereof, that is to say:-
This Invention consists in the employment of cod oil, horse grease, or other

page_text: fatty or greasy substance in combination with lime and soda or other alkali,
for the purpose of unhairing skins, and for preparing them for tawing or
tanning, and in the employment of cod oil, horse grease, or other fatty or
greasy substance in combination with soda or other alkali, and the usual
materials containing tannic acid, (such as oak bark, minosa bark, terra japonica,
cutch, divi-divi, sumach, &c.,) for the purpose of tanning. Warm water is
employed for making the solutions and extracts of these materials, and the
skins are agitated while immersed in the liquid, either in cylinders, with pro- .
jections or pegs on their inner surface, and kept rotating, or in open vessels or
pits, or by manual labor, or by any other suitable means.
For the purpose of preparing the skins, cod oil or other fatty substance is
added to a solution of lime and water; and for tanning, I use extracts of the
materials containing tannic acid, made with warm water, and carbonate of
soda, and oil or grease.
The manner in which this Invention is carried into effect is as follows:-
If, for example, 25 calf skins, or 4 ox hides, or 7 ox butts, or about the same
weight of other skins are to be unhaired and prepared, four pounds newly
burnt carbonate of lime in lumps are to be placed in an earthenware pan, and
a small quantity of cold water sprinkled over it, in order to produce hydrate of
lime. When the lumps break up more water is to be added, so as to form. a
white paste, to which are to be added four ounces of cod oil, and the whole is
to be well mixed. This is stirred into about 224 lbs. of water at a temperature
of 100° Fahrenheit, contained in a tub or pit, and 4 lbs. of carbonate of soda
(previously dissolved in a separate pan) are well mixed with it. The green
skins or hides do not require to be washed first, but are, in preference, steeped
into this liquor as they have been taken off the animal, and well moved about
in it, so that every part of them may be exposed to the action of the liquor as
well in the lower as in the upper part of the tub or pit. For the first fifteen
minutes it would be useful to have the skins stamped with a wooden stamp or
pestle hollowed out at bottom, but afterwards the skins will only require to
be stirred about and lifted out to be replaced in a reversed order every ten
minutes, until (if they are large skins or hides) they have been in about one*
hour (but a less time would suffice for small skins), and the hair will then be
found to be loose in most parts of the skins. By working for a little longer, or
by making the liquor stronger by the employment of more soda or less water,
the hair might be removed; soon after, however, I prefer to leave the skins
at rest in the tub or pit for the purpose of swelling, after having first added
about 112 lbs. water at about 100° Fahrenheit, so that all the skins may be

page_text: perfectly covered by the liquor, which would not injure the skins even if:left;in
for several days; however, 12 to 14 hours will be sufficient to loosen the hair
and the epidermis, and to swell the true skin, which, after having been,washed,
unhaired, and fleshed, will thus be further prepared, and quite ready for tanning
or 'tawing.
qui
It is well known that lime, if left in the skins after unhairing, opposes the
penetration of tannin, as the lime when combined with the greasy matter of
the skins is difficult to be removed, and forms, when..left, tannate of -lime,
which makes the leather hard and dry. To purge or work out every particle
of lime previous to tanning is therefore necessary,when.supple leather, is
required; and a variety of processes have been recommended for this purpose.
I find that the compound of hydrate of lime with grease or oil and an addition
of soda is more soluble, and therefore may be-simply.and.ieasily removed by
merely washing out.
Dry hides and skins may be treated in the same manner for unhairing
'and swelling by the same liquor, which will be found to. soften them,very
expeditiously.
The stamping or stirring and tossing about of the skins-for.. unliairing,, as
well as for tanning; may be done by machinery such as is now used, or may be
suitable to be used for the purpose. The tanning-of the skins may be effected
by any well-known process, or in the following: manner, which is, however,
more particularly applicable to skins of light weight: An extract of any
of the usual tanning materials is to be made by adding sufficient quantity of
water of a temperature of 100° Fahrenheit, to which is added-carbonate of soda
in combination with cod oil, or other grease or oil; for instance, ifioak bark
is used, to 800 lbs. of such bark 8 lbs. of carbonate of soda and.5 oz. of cod
oil are, added. .
The skins are first placed for some hours in a weak liquor of this description,
or in liquor which, having. been used in a previous operation, has become
weakened by it, and is gradually made stronger. The skins are:stirred about
in this liquor (képt at about 100° Fahrenheit temperature) by manual labor or
mechanical means, and lifted out at intervals of about eight hours, to be
sleeked, and hung up for a few hours, and immersed again until sufficiently
done, which will be according to the thickness of the skins, in about 18.to.5.0
hours of immersion in the liquor."
:
And having now described the nature of the said Invention, and the manner
in which the same may be performed, I declare that I am aware that lime in
combination with soda or other alkalies has been-before-used for unhairing

page_text: and preparing, and that soda has been used for making extracts for tanning,
and I do not, therefore, claim the use of any of these substances separately;
but what I do claim is,-
First, the employment of oil, grease, or other fatty substance in combination
with lime and soda, or other alkali, for the purpose of unhairing or preparing
skins.
Second, the employment of oil, grease, or other fatty substance in combina-
tion with soda or other alkali, and with materials containing tannic acid, for
the purpose of tanning skins, as herein-before described.
In witness whereof, I, the said Charles Augustus Preller, have hereunto
set my hand and seal, this Twenty-sixth day of December, One
thousand eight hundred and fifty-six.
C. A. PRELLER. (LS.)