AN IMPROVEMENT IN COMPOSITIONS FOR TANNING SKINS AND HIDES OF ALL DESCRIPTIONS
Year: 1860

page_text: LETTERS PATENT to William Edward Newton, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Civil Engineer, for the
Invention of "AN IMPROVEMENT IN COMPOSITIONS FOR TANNING SKINS AND
HIDES OF ALL DESCRIPTIONS."-A communication from abroad by C. L.
Robinson and T. G. Eggleston, both of Fox Lake, Dodge County, State
⚫ of Wisconsin, United States of America.
Sealed the 31st January 1861, and dated the 31st August 1860.
PROVISIONAL SPECIFICATION left by the said William Edward Newton
at the Office of the Commissioners of Patents, with his Petition, on
the 31st August 1860.
I, WILLIAM EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Civil Engineer, do hereby declare the nature
of the said Invention for "AN IMPROVEMENT IN COMPOSITIONS FOR TANNING SKINS
AND HIDES OF ALL DESCRIPTIONS," to be as follows:-
This Invention of an improvement in compositions for tanning skins and
hides of all descriptions, consists in the employment, in combination with
terra japonica (also called catechu and cutch as the tanning agent) of sulphuric
acid for the purpose of removing certain injurious impurities in the catechu;
carbonate, sulphate, or calcined magnesia, and sulphate of potassa are also
added and employed as plumping and alterant agents. These materials are
combined and used in the following manner :-Dissolve in about one hundred
gallons of water about fifteen or twenty pounds of terra japonica, heat and stir
the mixture until the terra japonica is dissolved; then cautiously add a small
quantity of sulphuric acid; stir the liquid rapidly, and bring it to the boiling

page_text: point; then skim off the scum, and run the liquor into a tank, and allow it
to cool, when the impurities will fall to the bottom in the form of a sediment.
Then rack off the clear liquor into another vessel, and add a small quantity of
carbonate or calcined magnesia, and a smaller quantity of sulphate of potassa
and add more water. The hides or skins may then be placed in this liquor,
and moved about from time to time to prevent them from spotting; adding
occasionally fresh liquor with the addition of a little sulphate of magnesia.
When the hides are perfectly. tanned they are to be taken out and treated in
the same way as in ordinary tanning.
The object of the employment of the sulphuric acid is to remove or throw
down from the terra japonica or catchu the resins, lime, and other impu-
rities it contains, and the leather produced is then more durable, flexible, and
stronger than leather tanned in the ordinary way; it is also free from brittle-
ness. Some of the salts will harden. the leather, and make it more useful for
sole leather. The proportions of the several ingredients must depend upon
the description or kind of leather required.
SPECIFICATION' in pursuance of the conditions of the Letters. Patent, filed
by the said William Edward Newton in the Great Seal Patent Office on
the 27th February 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane, in the County
of Middlesex, Civil Engineer, send greeting.
WHEREAS Her most Excellent. Majesty Queen Victoria, by Her Letters
Patent, bearing. date the Thirty-first day of August, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-fourth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said William Edward Newton, Her special license that I, the said
William Edward Newton, my executors, administrators, and assigns, or such
others as I, the said William Edward Newton, my executors, administrators,
and assigns, should at any timé 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 "AN IMPROVEMENT IN COMPOSITIONS FOR TANNING SKINS AND HIDES
OF ALL DESCRIPTIONS," being a communication from abroad, upon the condition
(amongst others) that I, the said William. Edward Newton, by an instrument

page_text: in writing under my hand and seal, 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 William Edward Newton, 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 (that is to say):-
This Invention of "An Improvement in Compositions for Tanning Skins
and Hides of all Descriptions," consists in the employment, in combination
with terra japonica (also called catechu and cutch) as the tanning agent of
sulphuric acid for the purpose of removing certain injurious impurities .n the
catechu; carbonate, sulphate, or calcined magnesia, and sulphate of potassa are
also added and employed as plumping and alterant agents. These materials
are combined and used in the following manner :-First, make up the terra
japonica tanning liquor, which I will call No. 1, as follows:-Put about one
hundred and twelve gallons of water into a suitable kettle placed over a fire,
and add. fifteen pounds of common terra japonica to it, and while the heat in
the fire is continued, stir up the liquor until the terra japonica is dissolved;
add to this three ounces of common sulphuric acid very cautiously, and. stir
the liquor very rapidly. It is dangerous to pour strong sulphuric acid into
hot water, therefore it should either be poured in when the water is cold, or it
should be greatly diluted; this combines with the impurities, and precipitates
them. Now bring this liquor to the boiling point, and skim off all the froth
which rises to the surface; then pour out the liquor into a large tank or
wooden vessel to cool. During this period of cooling a considerable amount
of sediment falls to the bottom; this consists of insoluble impurities, which
not only retard the tanning process, but injure the quality of the leather, if
retained in the tanning vats. These impurities consist of lime, alumina,
gummy and resinous matter, and sometimes starch which is employed for
the purpose of adulteration, and they frequently amount to from thirty to forty
per cent. of the solid parts of the terra japonica. The lime and the resin
tend to render the color of leather very dark, and they also make it very
brittle. In precipitating them with sulphuric acid, use such a
quantity of the
latter as will not sensibly affect the tannin, while it removes the injurious
substance. Now rack off the clear liquor from the cooling tank into a vat,
leaving the sediment behind, and use it as follows:-For upper leather, add
to the quantity of racked-off liquor described above as No. 1, about one-fourth

page_text: of an ounce of dissolved carbonate or calcined magnesia and about the sixteenth
of an ounce of sulphate of potassa, and then add as much water, as will reduce the
liquor No. 1 to one-half its strength, which will be about a sufficient quantity
for ten good sized hides. The whole is now stirred up, and forms. the tanning
liquor No. 2. The hides are now placed in this liquor, and are moved fre-
quently the first two days, so as to allow the substances in the liquor to act
uniformly, and at the same time prevent the .hides from becoming .spotted on.
those places where they come in contact with each other.
Fresh clear liquor No. 1 must always be kept prepared and at hand to keep
up and increase the strength of the vat liquor No. 2, in which the hides are
being tanned. About thirty-five gallons of it are added every second day at
the early stage of the process, and one ounce of sulphate of magnesia. The
hides are lifted out to put in the fresh liquor. The quantity of magnesian
salt added will depend upon the amount of plumping, which the hides require,
and the practical tanner will judge of this by inspection. Greater quantities
of fresh liquor are added toward the end of the process, so as to increase the
strength of liquor No. 2. The same practice is pursued in this-respect-as-in
tànning with oak and hemlock liquor. When the hides are perfectly tanned,
they are lifted out of the liquor, and are afterwards 'treated exactly like hides
tanned by common processes. It requires from two to four weeks to tan cow
hides for upper leather, as described, and when the operation is effected per-
fectly, the tanner can judge, by examining the hide, whether the
process has
been effective. This method of tanning is suitable for all upper leather for
calf, sheep, and other skins with the hair removed, or with the fur retained;
furs. tanned in this manner are free from the attacks of moths and insects.
In tanning calf, goat, sheep, and other skins and furs, it is preferable to
employ a liquor somewhat weaker than No. 2, but otherwise the process.is
exactly the same. The length of time required for effecting the complete
tanning of any skin depends much on its size and thickness, but it is only by
the usual method of inspection that a tanner cap judge when the skin is com-
pletely tanned. About one hundred skins or fifty calf skins may be tanned
in the same quantity of liquor as that for the ten hides' already described.
Such leather as harness and sole leather is made harder and more firm than
upper leather, but the liquor for cow and ox hides is made up exactly like
No. 2, as described, and the process is conducted in the same manner, with
the exception that two ounces of sulphate of potassa is employed or added to
the first liquor. which the hides receive. This salt renders the sole leather
hard and firm; if a large quantity were used for upper leather, it would make
it too hard. In tanning sole leather, the same method of operating is pursued

page_text: as for upper leather, the liquor being made stronger towards the end of the
process. It takes from four to eight weeks to tan harness leather, and from
six weeks to three months to tan sole leather with this improved liquor. Fur
and sheep skins may be tanned in from ten to fourteen days. The sulphuric
acid acts the part of an alterant as well as a purifier of the catechu, or the
colours produced in the hides and skins tanned by this process are a beautiful
dark cream.
This improvement does not quicken the process of tanning materially from
the old method, although it is somewhat quicker, but it makes far superior
leather to that which has hitherto been produced. By removing the resin,
the lime, and other impurities from terra japonica, as described, the leather
produced is free from all brittleness, is more flexible, stronger, and more
durable than common bark tanned or other catechu tanned leather. In
making up new vats old liquors are used in place of water, when these can be
obtained. In tanning with terra japonica, the operations are more cleanly,
simple, and less laborious than in tanning with bark; and, besides, the business
may be conducted wherever water can be obtained altogether independent
of hemlock and oak barks.
Having now described this Invention of an improvement in compositions.
for tanning skins and hides of all descriptions, and having explained the
manner of carrying the same into effect, as communicated to me by my
foreign correspondent, I would observe, that I do not claim the use of sulphuric
acid in tanning, except when the same is used in the manner or for the
purpose herein described; but what I consider to be new in the above
described process, and therefore desire to claim as the Invention secured to
me by Letters Patent as aforesaid, is, the employment of terra japonica in
combination with sulphuric acid and the magnesian and potassium salts, as
above described.
'
1
In witness whereof, I, the said William Edward Newton, have here-
unto set my hand and seal, the Twenty-seventh day of February, in
the year of our Lord One thousand eight hundred and sixty-one.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
W. E. NEWTON. (L.S.)