AN IMPROVED COMPOUND POR TANNING LEATHER
Year: 1868

page_text: LETTERS PATENT to Alexander Clark, of 53, Chancery Lane, in
the County of Middlesex, Engineer, for the Invention of "AN
IMPROVED COMPOUND POR TANNING LEATHER."-A communication from
abroad by Louis Henry Dennis and Otho Richard Brown, both of
Stafford Springs, Tolland County, State of Connecticut, United
States of America.
Sealed the 8th January 1869, and dated the 19th August 1868.
PROVISIONAL SPECIFICATION left by the said Alexander Clark at
the Office of the Commissioners of Patents, with his Petition, on the
19th August 1868.
I, ALEXANDER CLARK, of 53, Chancery Lane, in the County of
Middlesex, Engineer, do hereby declare the nature of the said Invention
for "AN IMPROVED COMPOUND FOR TANNING LEATHER," to be as follows:-
The object of this Invention is to produce a tanning compound by
which the leather can be completely and satisfactorily tanned without
requiring the use of the ordinary bark extract now used.
The Invention consists in a combination of catechu, commonly known
under the name of cutch, with common lye in various proportions. This
mixture is or may be used alone or together with coloring matter, such

page_text: as alum, and with salt or other material that will serve to plump the
leather, if so desired; but I desire it to be understood that the com-
bination of cutch and lye is the substance of the present Invention, the
other ingredients being merely dependent upon certain special results to
be obtained.
The proportions in which these ingredients are mixed vary with the
kind of leather to be tanned. I will mention the proper receipts for the
most important varieties of leather.
For tanning harness leather I mix the substances in the following
proportions 4 pounds cutch, 3 pints common lye, 4 ounces of alum.
For wax leather (split leather) I use with 3 pounds of cutch 2 pints
of lye and 3 ounces of alum.
For calfskins I use with 2 pounds of cutch 1 pint of lye and 2 ounces
of alum.
For sheepskin I use with one pound of cutch one pint of lye and one
ounce of alum.
In either case the proportions may be varied to produce certain desired
results. The cutch alone will make the leather brittle and hard. The
lye will soften it to the required degree. The alum being only used for
coloring can be dispensed with, or other matter may be used in its place.
Salt may be used in variable quantities to plump up the leather and to
make it spongy when so desired. The whole mixture is in either case
boiled together, and the leather is then immersed in it long enough to
be thoroughly tanned, for which purpose the harness leather should be
steeped for from 18 to 20 days, the wax leather for from 12 to 14 days,
the calfskin during 7 to 3 days, and the sheepskins from 2 to 4 days.
When the leather has been thus tanned it is ready to be submitted to
the ordinary process of finishing.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Clark in the Great Seal Patent Office on
the 13th February 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of August, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alexander Clark, Her special licence
that I, the said Alexander Clark, my executors, administrators,
and assigns, or such others as I, the said Alexander Clark, 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 "AN IMPROVED
COMPOUND FOR TANNING LEATHER," a communication to me from abroad by
Louis Henry Dennis and Otho Richard Brown, both of Stafford Springs,
Tolland County, State of Connecticut, United States of America, upon the
condition (amongst others) that I, the said Alexander Clark, 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 Alexander Clark, 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):
*-
The object of this Invention is to produce a tanning compound by
which the leather can be completely and satisfactorily tanned without
requiring the use of the ordinary bark extract now used.
The Invention consists in a combination of catechu, commonly known
under the name of cutch, with common lye in various proportions. This
mixture is or may be used alone or together with coloring matter, such
as alum, and with salt or other material that will serve to plump the
leather, if so desired; but I desire it to be understood that the com-
bination of cutch and lye is the substance of the present Invention, the
other ingredients being merely dependant upon certain special results
to be obtained,

page_text: The proportions in which these ingredients are mixed vary with the
kind of leather to be tanned. I will mention the proper receipts for the
most important varieties of leather.
For tanning harness leather I mix the substances in the following
proportions-Four pounds of cutch, three pints of common lye, four
ounces of alum.
For wax leather (split leather) I use with three pounds of cutch two
pints of lye and three ounces of alum.
For calfskins I use with two pounds of cutch one pint of lye and two
ounces of alum.
For sheepskins I use with one pound of cutch one pint of lye and one
ounce of alum.
In either case the proportions may be varied to produce certain desired
results. The cutch alone will make the leather brittle and hard. The
lye will soften it to the required degree. The alum being only used for
coloring can be dispensed with, or other matter may be used in its place.
Salt may be used in variable quantities to plump up the leather and to
make it spongy when so desired. The whole mixture is in either case
boiled together, and the leather is then immersed in it long enough to
be thoroughly tanned, for which purpose the harness leather, should be
steeped for from eighteen to twenty days, the wax leather for from twelve
to fourteen days, the calfskins during seven to nine days, and the sheep-
skins from two to four days. When the leather has been thus tanned it
is ready to be submitted to the ordinary process of finishing.
Having described the nature of this Invention, and the manner of
performing the same, I declare that what I claim as the Invention to be
protected by the herein-before in part recited Letters Patent is, the
tanning compound composed of the ingredients in about the proportions
set forth.
In witness whereof, I, the said Alexander Clark, have hereunto
set my hand and seal, this Thirteenth day of February, in the
year of our Lord One thousand eight hundred and sixty-nine.
ALEXB. CLARK. (L.S.)