CERTAIN IMPROVEMENTS IN TANNING
Year: 1826

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
JOHN KNOWLYS, of Trinity College, Oxford, Esquire, send greeting.
WHEREAS His present most Excellent Majesty King George the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the First day of August, in the seventh year of His reign, did,
for Himself, His heirs and successors, give and grant unto me, the said
Thomas John Knowlys, and also to WILLIAM DUESBURY, of Bonsal, in the
County of Derby, Colour Manufacturer, His especial licence that we, tho said
Thomas John Knowlys and William Duesbury, our exors, adñiors, and
assigns, or such others as we, the said Thomas John Knowlys and William
Duesbury, our exors, adñiors, or assigns, should at any time agree with,
and no others, from time to time and at all times during the term of
years therein expressed, should and lawfully night make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, our
Invention of "CERTAIN IMPROVEMENTS IN TANNING;" in which said Letters Patent
is contained a proviso obliging us, or one of us, the said Thomas John Knowlys
and William Duesbury, by an instrument in writing under our or one of our
hands and seals, particularly to describe and ascertain the nature of our said
Invention, and in what manner the same is to be performed, and to cause
the same to be inrolled in lis said Majesty's High Court of Chancery within
six calendar months next and immediately after the date of the said recited
Letters Patent, as in and by the same, reference being thereunto had, will
more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said

page_text: Thomas John Knowlys, do hereby declare the nature of our said Invention to
consist in the following improvements in tanning, that is to say:-In causing
tan liquor to enter more speedily into the pores of hides or skins in the process
of tanning by previously exhausting the air from the said pores; and in
further compliance with the said proviso I do hereby describe the manner in
which our said Invention is to be performed by the following description of
the same improvements, reference being had to the Drawing annexed, and to
the figures and letters marked thereon, that is to say:-
DESCRIPTION OF THE DRAWING.
Figure 1 is the section of an air-tight vat fitted with our said improvements.
A is the tanning liquor. B is a manhole to put the hides in at and clean the
vat out by. C is the cover to this manhole, which fits into a rabbit, and being
lined round the edge with leather is kept tight down by tho pressure of the ex-
ternal atmospheric air when the air in the vat is exhausted. D is a pipe and
air cock which leads to an air pump or other exhausting apparatus. E is an air
cock for the re-admission of air into the vat. F is a pump to draw off the tan
liquor when required. G, G, are two hooks for suspending the hides edgeways
in the vat. H is the hide so suspended, and r, r, r, r, r, r, are leaden weights
to keep the hide from being buoyed up by the liquor. Fig. 2 is a plan of
Fig. 1.
Having described the Drawing annexed I will proceed to explain the process
to be adopted as follows (that is to say):-After the hides have undergone the
ordinary preparations, such as lining or other processes, for the purpose of
taking off the air, we immerse them in the said air-tight vat, filled all but two
or three inches with tan liquor; we then close the vat, and by means of an air
-pump or other means of exhaustion applied to the pipe D, we draw out the air
contained in the vat, and the pores of the hides, whereby the tan liquor more
readily enters these same pores. The first liquor that is used must be weak,
and the strength encreased daily. The liquor should be drawn off or pumped
away every day, and the hides left to hang an hour or more in the vat, so that
the liquor may drop from them, and that they may imbibe the air again, which
air is again to be pumped out or exhausted after fresh liquor has been intro-
duced into the vat (some oil or grease should be put upon the surface of the
tan liquor in the vat for the purpose of breaking the bubbles which are raised
by the air as it escapes from the pores of the hides, and which would other-
wise rise and enter into the pipe communicating with the air pump). The vat
may be made of copper or wood, but no iron should be used anywhere in its
construction, as that metal affects the colour of the hides.

page_text: Now whereas we claim as our Invention the quickening the process of
tanning by exhausting the air contained in the hides by means of the improve-
ments herein-before described. And such Invention being, to the best of our
knowledge and belief, entirely new, and never before used within that part of
Ilis said Majesty's United Kingdom of Great Britain and Ireland called
England, His said Dominion of Wales, or Town of Berwick-upon-Tweed, I
do hereby declare this to be our Specification of the same, and that I do verily
believe this our said Specification doth comply, in all respects, fully and without
reserve or disguise, with the proviso in the said hercin-before in part recited
Letters Patent contained; wherefore we hereby claim to maintain exclusive
right and privilege to our said Invention.
In witness whereof, I, the said Thomas John Knowlys, have hereunto
set my hand and seal, this Twenty-seventh day of January, in tho
year of our Lord One thousand eight hundred and twenty-seven.
THOMAS JOHN (L.S.) KNOWLYS.
AND BE IT REMEMBERED, that on the Twenty-seventh day of January,
in the year of our Lord 1827, the aforesaid Thomas John Knowlys came
before our said Lord the King in His Chancery, and acknowledged the
Specification aforesaid, and all and every thing therein contained and specified,
in form above written. And also the Specification aforesaid was stamped
according to the tenor of the Statute made for that purpose.
Inrolled the First day of February, in the year of our Lord One
thousand eight hundred and twenty-seven