IMPROVEMENT OF SOUR TANNIN SOLUTIONS AND FOR PLUMPING HIDES THEREBY
Year: 1877

page_text: LETTERS PATENT to William Emery Nickerson, of the State of Massachusetts,
of the United States of America, for the Invention of THE IMPROVEMENT OF
SOUR TANNIN SOLUTIONS AND FOR PLUMPING HIDES THEREBY."
led the 18th January 1878, and dated the 26th November 1877.
"
COMPLETE SPECIFICATION filed by the said William Emery Nickerson at
the Office of the Commissioners of Patents on the 26th November 1877.
WILLIAM EMERY NICKERSON, of the State of Massachusetts, of the United States
of America. "THE IMPROVEMENT OF SOUR TANNIN SOLUTIONS, AND FOR PLUMPING
HIDES THEREBY."
The barks of many wooded plants, shrubs, and trees, when subjected to infusion
or decoction, yield, among other matters, a solution known in the arts as "tannin,"
and in chemistry as "tannic acid." It is this substance in solution by which
tanners accomplish the tanning of hides for converting them into leather, the tannic
acid during the process being combined with the gelatine of the hide.
Such solutions, after a short period of time, generally become more or less changed
in their character or nature, the resultants being liquids in which tannic, gallic, acetic,
and carbonic acids, essential oil of turpentine, gums, or resinous substances, and
alkalies, more or less abound, combined with decaying vegetable or putrescent
animal matter.
The presence in the tannic solution of the decaying vegetable and animal sub-
stances, besides liable to injure the bides, often seriously interferes with the proper
action of the tannic acid and other matters of the solution that are useful in the
tanning process.
Prior to tanning the heavier kinds of hides, such as are used for the manufacture of
or for conversion into sole leather, they, after having been relieved of hair and
properly "fleshed," are generally submitted to what is termed "plumping" or
raising," the object of which is to extend and soften their fibres, in order to enable
the tannin to have full or proper access to the gelatine therein.
This "plumping" or "raising" has usually been accomplished heretofore in various
ways. In one of these, tanning liquor, which may have been in use, and in which

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the gallic and acetic acids have been developed, is employed, it usually being termed
tailings" or sour liquor." Into this the hides, after having been depilated and
fleshed," have been immersed and allowed to remain for a sufficient time to
produce the desired effect. In such "sour liquor" however, the animal and vegetable
matters, particularly when putrescent, seriously interfere with the proper operations
of the other constituents of the solution. It becomes, therefore, very desirable to
separate from the "sour liquor" before using it, such matters as are thus deleterious
to the process of "raising" or "plumping" the hides by means of it. This I have
discovered can be effected by distillation..
.
To accomplish such distillation, I make use of a still or distilling apparatus of
any proper kind. In this, I prefer to heat the sour liquor by means of steam let
into pipe coiled within the body of the vessel holding the liquor; the vapors liberated
from the liquor being conducted from the still to and through a condenser, whose
temperature is to be maintained at a sufficiently low point for their proper
condensation.
"
The distillate thus produced is a new manufacture or composition for the purpose of
effecting the "raising" or "plumping" of hides or skins, and its use for such effects is
new and productive of valuable and important results, for by it the hides after being
plumped" are in a better state for the reception of the tanning liquor subsequently
employed in effecting the tanning of them. In using the distillate, it, in a sufficiently
diluted condition, is to have the hides immersed in it, they being removed from the
solution or solutions used, and these latter to be suffered to drain from them (the
hides), as may be necessary to complete the process; to facilitate which, especially
in cool weather, if desirable, heat may be employed, to keep the solution moderately
warm, or at the proper or best temperature.
The number of vats used, and the number of steepings of the hides therein, and
the times taken for such will depend on circumstances, well understood by tanners.
The quality of the leather produced under my improvement, or by the use of the
aforesaid distillate in the "plumping" or "raising" of the hides, will be found to be
much better than when the acid liquor in its normal condition is used.
I claim as of my discovery or Invention as follows:-
First. The described improved liquid compound or distillate from the sour liquor
herein-before mentioned.
"
Second. The described improvement in the process of "raising" or "plumping"
hides, such involving the use or employment, as explained, of the distillate from the
sour tanning liquor, substantially as set forth.
Third. The described improved manufacture, or a hide or skin "plumped" or
"raised" by means of a distillate, as set forth, applied to it, essentially as specified.
In witness whereof, I, the said William Emery Nickerson, have hereunto set
my hand and seal, this Ninth day of November 1877.