IMPROVEMENTS IN TANNING AND PRESERVING HIDES OR SKINS, WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO THE PRESERVATION OF Books, PAPERS, AND THE LIKE
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by John Henry Johnson at the Office
of the Commissioners of Patents on the 20th April 1880. A communication
from abroad by Paul Lacroix and Nicolas Beller, both of Paris, in the Republio
of France.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN TANNING AND PRESERVING HIDES OR SKINS,
WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO THE PRESERVATION OF Books,
PAPERS, AND THE LIKE." A communication from abroad by Paul Lacroix and
Nicolas Beller, both of Paris, in the Republic of France.
This Invention relates chiefly to the tanning of hides or skins and effecting their
preservation by the employment of a very rich tanning matter existing in the
bark of the pomegranate plant, whether in the condition of a tree or of a shrub,
and in the rind of the fruit of the same.
By means of the improved process goatskin, calf skin, sheep skin, and the like
may be tanned without being colored.
The rind of pomegranates and the root of the pomegranate are employed,
according to this Invention, for protecting manuscripts, printed books, and book
bindings from the attacks of worms.
It has not heretofore been possible to tan the skins hereinbefore referred to, as
they are tanned according to this Invention, without coloring them.
By employing however the rind of the fruit of the pomegranate plant, and even the
bark of the pomegranate tree or ahrub, and more especially of the shrub, according to
this Invention, from about fifteen and a half to about seventeen and a half pounds of
this substance previously reduced to powder is sufficient for the purpose of tanning
one dozen of skins, and in this quantity of the tanning substance an inappreciable
quantity only of coloring matter is contained.
A new tanning substance of great richness is thus obtained which is extracted
from the plant, and not from the bark of the plant only, but also from the rind of
its fruit.
The great importance of this novel application consists however more particularly
in the reduced quantity of coloring matter necessarily employed with the tanning
substance, in consequence of which the skins do not undergo the coloring which
always takes place in the processes heretofore employed; and by means of this
Invention a colourless tanning process is obtained yielding an entirely new product
LD.

page_text: capable of receiving the most rich and the most delicate shades of color, a result
which is unattainable by the means heretofore employed.
In carrying out this Invention it is preferred to adopt the process of treatment
hereinafter described. In order to treat morocco leather with powdered pome-
granate rind a large cask or a large tank is employed capable of containing about
two hundred and twenty gallons of water, and supported by arms provided at the
upper part with bearings for the reception of the crank shaft of a wheel carrying
arms or stirrers.
About two hundred and twenty gallons of water is a sufficient quantity for
treating eighteen dozen of average skins, and the water should be soft, in the first
place, and be subsequently raised to a temperature of from twelve to fifteen degreos
centigrade.
The water having been placed in the tank half the total quantity of pomegranate
rind necessary for tanning eighteen dozen skins is added, that is to say, about 157
pounds, allowing the ample proportion of about 17, pounds per dozen. The
pulverized pomegranate rind is then well mixed with the water, and the skins to
be tanned are afterwards introduced into the tank.
The mechanical stirrer or agitator is then placed in the bearings provided on the
arms of the tank, and motion is imparted to the stirrer by means of the crank, tho
stirrer being caused to act with some force at first and afterwards more gently, as
when the operations are commenced in the morning it is necessary to continue the
rotation all the day; after which the skins are removed from the tank, care being
taken to avoid any waste of the liquid.
The remaining 157 pounds of pulverized rind are then added to the liquid in the
tank, and the skins are replaced in the same. The stirrer, which will have been
removed in order to facilitate these operations, is then replaced and caused to
rotate for about 2 hours, after which it is left in repose for the night.
The operation lasts for about four days, during which time the skins should be
kept in motion, except during the night, and the tanning is then complete; it will be
simply necessary to take the skins out of the tank and spread thein on trestles to
allow the moisture to drain off, and afterwards dry them in the usual manner on
books.
The process may be varied whilst still employing the improved tanning
substances.
By means of this Invention a new industrial product is obtained consisting of
hides or skins which are tanned without being colored, and are capable of being
colored and shaded with the most rich and exquisite colors. It is also proposed to
preserve paper and the binding of books in the following manner :-
(1) By employing the action of the astringent properties of pomegranate rind
and of the root of the pomegranate tree, which is employed in the tanning of the
skins destined for the binding of books. Books already bound cither in calf,
morocco, or sheep skin may also be treated in the same manner.
(2) By the action of a mixture of a concentrated decoction of the same rind or
roots with the various kinds of paste employed in the binding.
(3) By soaking or pasting blank and printed paper in or with the said
decoction of the rind or roots.