IMPROVEMENTS IN THE PRODUCTION AND APPLICATION OF TANNIN OR TANNIC
Year: 1858

page_text: LETTERS PATENT to Henry Constantine Jennings, of No. 8, Great Tower
Street, in the City of London, Practical Chemist, for the Invention of
LETTERS PATENT to Henry Constantine Jennings, of No. 8, Great Tower
Street, in the City of London, Practical Chemist, for the Invention of
IMPROVEMENTS IN THE PRODUCTION AND APPLICATION OF TANNIN OR TANNIC
"
Street, in the City of London, Practical Chemist, for the Invention of
"IMPROVEMENTS IN THE PRODUCTION AND APPLICATION OF TANNIN OR TANNIC
NAVA
"
Sealed the 15th June 1858, and dated the 6th January 1858.
PROVISIONAL SPECIFICATION left by the said Henry Constantine Jennings
at the Office of the Commissioners of Patents, with his Petition, on the
6th January 1858.
I; HENRY CONSTANTINE JENNINGS, of No. 8, Great Tower Street, in the City.
of London, Practical Chemist, do hereby declare the nature of the Invention
for "IMPROVEMENTS IN THE PRODUCTION AND APPLICATION OF TANNIN OR TANNIC
ACID," to be as follows:
I take dense bog peat, preferring that called black bog peat to the light-
colored or superficial peat, in fact, the peat which contains the greatest
amount of paraffine, bitumen, and oily matters; this is exposed to the air in
discs or slabs as taken from the bogs, about two inches thick, and when
thoroughly dried by the atmosphere is ground into a fine powder; I then add
from 10,15,to 20. per centum of nitric acid of commerce, stirring and
mixing the whole together, in a few minutes a great heat will be generated,
and yellow or orange-colored vapours will be given off in abundance, which must
be kept in the vessel by covering the top; when the heat subsides, about ten
times its weight of water is added, and, the whole stirred to insure the perfect

page_text: mixture and saturation of the matters operated upon. The insoluble peat will
now be soluble, and give out tannin and tannic acid, and extractive of a deep
brown yellow colour; a small portion of hydrochloric acid and sulphuric acid
may be occasionally added. Heat, either by the naked fire or the use of steam,
may be employed to aid the decomposition. Into the tannin or tannic acid
and extractive thus produced I put the skins to be tanned, freed from hair,
offal, flesh, grease, &c. by lime and water in the usual manner.
I place a frame of basket or wicker to separate one skin from the other,
in case the skins are very large, so that they shall not press upon each
other; I then prepare another tank containing a solution of soda ashes or
common crystallized soda of commerce, made to contain from 30 to 40 per
cent. of soda, to which the skins are then subjected, and afterwards returned
into the tanning solution, this alternate process being repeated until the tanning
is complete.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Constantine Jennings in the Great Seal Patent
Office on the 5th July 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
CONSTANTINE JENNINGS, of No. 8, Great Tower Street, in the City of London,
Practical Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of January, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Henry Constantine Jennings, Her special licence, that I, the said Henry
Constantine Jennings, my executors, administrators, and assigns, or such others
as I, the said Henry Constantine Jennings, 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 THE PRODUCTION AND APPLICATION OF TANNIN
OR TANNIC ACID," upon the condition (amongst others) that I, the said Henry
Constantine Jennings, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly describe and ascertain the nature of the said Invention, and in

page_text: 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 imme-
diately after the date of the said Letters Patent.
:
NOW KNOW YE, that I, the said Henry Constantine Jennings, do hereby
declare the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
This Invention has for its object the production or development of a tanning
liquid or principle, a species of tannic acid, and some extractive or coloring
matter; the liquid to be so produced has the property of chemically combining
with the gelatine and animal fibre contained in skins, &c., and rendering the
gelatine and fibre insoluble, elastic, and indecomposable either by water
or atmospheric action, thereby producing leather. I take the bog peat that
has the greatest specific gravity or weight, commonly called deep black bog
peat, in preference to the light-colored or superficial peat, in fact, the peat
which is known to contain the greatest amount of paraffine, bitumen, and oil:
It is to be exposed to the atmosphere in slabs or dises from 2 to 4 inches
thick. If it can be conveniently practised, when thoroughly dried by the air,
it is to be reduced to a coarse powder by any mechanical means, as by stones
or by the bark mill. I then add nitric acid say, from 10 to 15, or 20 per
centum of the weight of the powdered peat to be operated upon, employing the
less or greater quantity of nitric acid according to the less or greater oily
quality of the peat, taking care to sprinkle the nitric acid gradually and
équally over the surface of the peat; and then stirring or mixing the acid
with the peat so as to distribute the liquid acid as much as possible amongst
the whole mass. In a few minutes a considerable action will take place,
the whole mass will heat and throw off orange-colored fumes in abundance;
when these begin to appear, a strong cover of wood is put over the vessel in
which the operation is performed, and weights are put upon the cover to
keep the fumes within the vessel as much as possible. When these fumes
begin to subside or have subsided; add about six to ten times as much water as
the acid that has been employed, taking care to sprinkle it over the surface as
much as possible, and in a few minutes stir the whole mass so as to combine
the water with the peat and acid; 'when a complete saturation of the mass is
effected, the vessel is to be supplied with more water until it rises to the upper
surface of the mixture; and it will then be useful to heat the whole mass up
to the boiling point, which may be done either in a pan or by passing steam
through earthenware tubes or coils; this heat may be continued for four
hours or even longer, the only intention thereof being to extract as much as

page_text: possible of tanning principle; after this operation a large portion of the bog
peat which was before insoluble in water has become soluble, and yields a
large quantity of tannin and extractive. If fresh peat just taken from the
bog, and containing a large quantity of water, is to be operated upon, it should
be put into a pan or a wooden vat with a steam coil, and five per cent. of
sulphuric acid of commerce mixed with the peat, and then heated to from
180° to 212° Fahrenheit, and kept acted upon by heat for about two hours
or more; the heat is then withdrawn, and from 10 to 15 per cent, of nitric acid
added, and well stirred or mixed and incorporated; after an hour has elapsed
the heat is again applied and continued until orange vapours begin to form,
which vapors are to be kept within the pan or vessel by means of a cover and
weights. When the liquid matter gives a decidedly brown or yellow color to
water, the heat may be withdrawn and the mass left to cool gradually; after
some hours (or as soon as the mass is cool) water is added to dissolve all the
extractive and tanning matter that has formed, and it will be most advan-
tageous to employ only so much water as will afford a liquid that has the density
of 25° of the barkometer or any hydrometer that gives the real density of
liquids; but it is to be observed that long-continued boiling will always furnish
the largest supply of tannic acid, and give the greatest density.
To remove the extractive or coloring matter that has been generated, I
add from 2 to 3 per cent. of chloride of tin (muriate of tin), and boil this
salt for a few minutes with the tanning extract produced by the above process;
the liquor is then of a very pale color, and produces a very light bright-colored
leather. It can also be used with advantage by adding sulphate of alumina
and common salt (muriate of soda), which equally tend to deposit the coloring
matter, or from 15 to 20 per cent. of hydrochloric acid may be employed for
the above purpose. When I have produced the tannic acid, tannin or tanning
liquor in the manner above mentioned, I employ a solution of the density of
12° of the barkometer (or any other instrument or means by which the
specific gravity of liquids may be ascertained); this liquor is put into a tank;
the skins freed from the hair or offal in the usual manner are put into the
liquid, those that are heavy being laid in an inner box or frame that has a
perforated bottom, with a frame of wicker or basketwork interposed between
each skin, so as to prevent them from pressing upon each other. I then have
another tank like the former; this tank contains a solution of carbonate of
soda, or soda ashes, or carbonate of potassa if cheap; the quantity of soda of
commerce to be dissolved is about 30 to 40 per centum. After the skins
have been exposed for 20 or 22 hours to the tanning liquor above mentioned,
I lift the portable and perforated frame by means of a small crane out of the

page_text: liquor; I let it drain for some time, when it no longer drops I swing it round
and let it descend into the tank that contains the carbonated alkali, say, soda,
and when it has remained immersed from one to two hours I lift it out, let it
drain, and then swing it round and let it descend into the original tanning
liquor, so on alternately every day, until the skins are completely tanned; it is
necessary that as the tannic acid gets into the skins or becomes expended,
fresh liquor shall be added, and it will be found most advantageous to increase
the density of the tanning liquor as the process proceeds, as it considerably
increases the weight of the goods and renders the leather more solid. By
means of changing or alternating the skins in the alkaline solution as above
mentioned, the combination of the tannic acid with the gelatine and animal
fibre is facilitated, as a double decomposition takes place; at each change of
solution or liquid the tannic acid takes up the soda, and gives off carbonic
acid, which, as it escapes, opens or ruptures the cells and permits the tanning
to enter and chemically combine with the gelatine.
Having now described the nature of the said Invention, and in what manner
the same is to be performed, I claim the production of tannin or tannic acid
from bog peat, and the application thereof to tanning purposes.
In witness whereof, I, the said Henry Constantine Jennings, have here-
unto set my hand and seal, this Fifth day of July, in the year of our
Lord One thousand eight hundred and fifty-eight.
Witness,
GEO. PITT.
H. C. JENNINGS. (L.S.)