VARIOUS IMPROVEMENTS IN THE ART OF TANNING ALL MANNER OF HYDES AND SKINS, AND IN THE CONSTRUCTION OF TAN PITS OR VATS, WITH SEVERAL UTENSILS APPERTAINING TO THE SAME
Year: 1797

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
MURPHY, of Hertford Street, in the Parish of Saint Pancras, in the County of
Middlesex, send greeting.
WHEREAS His most Excellent Majesty King George the Third did, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Twenty-seventh day of January, in the thirty-seventh year of His
reign, give and grant unto me, the said James Murphy, His especial licence
that the said James Murphy, during the term of years therein mentioned,
should and lawfully might use, exercise, and vend, within England, Wales, and
the Town of Berwick-upon-Tweed, my Invention of "VARIOUS IMPROVEMENTS IN
THE ART OF TANNING ALL MANNER OF HYDES AND SKINS, AND IN THE CONSTRUCTION
OF TAN PITS OR VATS, WITH SEVERAL UTENSILS APPERTAINING TO THE SAME;" in
which said Letters Patent there is contained a proviso, obliging me, the said
James Murphy, by an instrument in writing under my hand and scal, to
cause a particular description of the nature of my said Invention, and in what
manner the same is to be performed, to be inrolled. in His Majesty's High
Court of Chancery within six calendar months after the date of the said
recited Letters Patent, as in and by the same, relation being thereunto had,
may more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
James Murphy, do hereby declare that my said Invention is hereby parti-
ticularly described under five general heads, that is to say :-

page_text: .
First, the manner of constructing the tannery, with the several utensils for
heating the same.
Secondly, the manner of preparing an alkaline ley, to be used as a menstruum
in tanning.
Thirdly, the manner of extracting an astringent liquor or ouse from certain
vegetable substances herein-after named.
Fourthly, the manner of concentrating the sail astringent liquor.
Fifthly, the manner of combining the astringent particles of the ouse with hides
and skins, so as to produce leather of a superior quality in a very short time.
First. It being admitted by all conversant in the tanner's art, that a
degree of warmth of the temperature of the living animal body conduces both
to accelerate the operation of tanning and to produce leather of a superior
quality, which is evident from the process being performed more speedily and
effectually in warm weather than in cold. "it is obvious, therefore, that a
tannery so constructed as to embrace these advantages will be a great
nequisition in this important art, and this, according to my Invention, may be
done by means at once simple and economical. The designs hereunto annexed
will help to illustrate this part of my Invention. N. B., similar letters refer to
different parts in the plans, sections, and elevation respectively: 1", let the
quadrangle A, B, C, D, represent the general plan of the tannery; No. 1, the
plan of half the substructure, around which are formed subterranean sewers to.
carry off the moisture of the circunjacent ground; No. 2; the ground plan, being
the top of the vats; No. 3, 'the longitudinal section on the line L, M; No. 4,
the elevation on the line A, B; No. 5, the transverse section on the line
.N, O; this section shews that the hither part of the manufactory is raised two
stories high, of which the upper story is for drying the leather. 2, E, a
furnace from whence heated air and smoke are conveyed along the
manufactory by the subterranean flues F, F, to the vertical flue at G;
these flues are covered with tiles or flags of about two inches thick, leaving
apertures a, a, for the heat to ascend to the bottom of the vats. The joints
between are filled up with a strong cement. 34, immediately over the flues arc
placed the vats distributed in the manner expressed in the plan No. 2; b, b,
are the vats for the hides; c, c, the vats for the skins; d, d, aro cisterns. Both
vats and cisterns may be formed of sound oak, or beach, or deal, made very
tight in the joints, the external surface covered with paint, and over this a coat
of thin sheet lead or copper, or some other metallic coating; m, m (transverse
suction, No. 5), are pipes of wood, by means of which the exhausted ouso or
water may be discharged from the vats on opening the plugs at a, n. 4th, all
the solid parts about the vats should be composed of pulverized sea coal or

page_text: charcoal, or else of coal ashes or some other substance of a dry, warm, and
uncorrosive nature. 5th, H is a common boiler or steam kettle, of iron or
copper, fixed over the furnace E, in the usual manner, which being partly filled
with water, a fire is lighted in the furnace, and the water made to boil gently.
The steam thus generated is conveyed among the vats by an horizontal pipe of
copper or lead II, K, I, having one end pierced through the side of the boiler,
and soldered thereto above the surface of the water. From the said pipe H, K, I,
a number of lateral tubes E, E, branch out and distribute the steam into the
hollow spaces at the sides and ends of the vats; 9, 9, are cocks or valves to
admit the steam to or exclude it from any particular vat;,, are ventholes
for the steam to ascend to prevent the pipes from bursting. All the superfluous
steam is carried away by the vertical flue at I; in proportion as the water in the
boiler evaporates, a supply is furnished by an adjacent cistern, and the same
quantity incessantly preserved by means of a cock and floating ball fixed in the
boiler. 6th, should the subterranean flues F, F, want cleaning at any time, a
ventilator, placed at an aperture at G or I, will effect that purpose. Hero
also must be a sliding plate of iron to shut up the vertical flue I, occasionally,
in order to prevent the evaporation of the heat; and at the apertures K, K,
in the furnace E, are metallic doors for similar purposes. Thus by concentrat-
ing the licated air, smoke, and steam, issuing from the said two furnaces and
two boilers, a series of seventy-six vats may be constantly kept in a moderate
degree of heat, which, however, should never exceed 140 of Farenheit's scale.
The annexed designs will fully explain all other parts of the tannery, whose
several dimensions may be ascertained by the scale. 7th, although I have here
illustrated my Invention for a tannery only by a quadrangular plan, yet a
circular or polygonal or mixed figure will answer the same purpose, the propor-
tions of which may be varied at discretion; and they may be constantly kept
warm in the manner above described, or in any other more expedient mode of
distributing heated air, sınoke, and steam. As to the several other appurtenences
requisite for a tanning manufactory, I form them in the usual manner, with
the difference, however, that I apply the power communicated by the rotary
motion of the bark mill to work a pump for raising of water into an elevated
cistern for supplying the boiler.
Secondly. The manner of preparing an alkaline ley:-1 Take of the best
weed or wood ashes that have been burnt within door, and immediately after
laid by in a covered vessel of wood 20lb., lixiviate them with twenty gallons
of boiling water, to which add six ounces of quick lime; let the extract when
cool be drawn off into a covered cistern, and kept for use: if the ashes contain'
any more alkali the lixiviation should be continued. 2nd. If a more caustic

page_text: menstruum be required, add one pound or more of fresh burnt lime to every
twenty pound of the ashes. 3. Or if a very caustic menstruum be required.
add, in place of lime, one pound of sulphur to every twenty-five pound of the
ashes. 4. Or in place of the above may be used a dilute solution of vegetable
alkali, obtained from refined wood or weed ashes, or Dantzic pearlash. 5th. Or
a dilute solution of mineral alkali, obtained from sweet barilha, crystallized
sod, or kelp. 6. Great care must be taken that all the lime has subsided,
and that the ley be perfectly limpid before it is used, otherwise it will be apt
to blacken the leather. A drop of the solution of corrosive sublimate let fall
into a glassful of the liquor will be turned into a liver colour mixed with yellow,
if any particles of the lime be present; to remedy this, add a little of the
unmixed ley, and it will effectually precipitate the lime.
.
Thirdly. The manner of extracting an astringent liquor or ouse:-1 Take
of the first alkaline menstruum above mentioned twenty gallons, of soft water
twenty gallons, of oak bark, finely ground, thirty pounds; let the whole be put
in a wooden vessel and gradually made to boil in a bath heat, taking care to
agitate the bark often; let the heat be discontinued, and draw off the super-
natant liquor by a leather tube, at the mouth of which is fixed a strainer, and
let it be preserved in casks or other vessels of wood till wanted for use, or else
conveyed immediately into the vats, whilst it is milk warm. A second extract is
made in a similar manner, by adding half of the above quantity of ley and water;
after this, the residuum is removed into a cistern and there left to macerate in ley
until the virtue of the bark is wholly extracted. Both these decoctions are to
be used in tanning the strongest and best hides. 24. Or instead of the above
process, use the following: put thirty pounds of ground oak bark into a cistern,
and let twenty gallons of the aforesaid ley, mixed with twenty gallons of soft
water, be heated in a separate vessel, aud when the liquor is on the point of
boiling pour it on the bark and agitate the mixture till it cools, then decant the
decoction, repeat the operation, and apply the ouse obtained from the residuum
in making a fresh extract. 3rd. Or the said alkaline menstruum may be sub-
stituted for water in the tan pits after the hides are placed therein between strata
of powdered bark in the usual way. This method may be advantageously adopted
in the common tan yards. The effects of the menstruum in either case will
eventually be the same, namely, to extract from the bark all its astringent and
resinous properties, and to accelerate the combination of these properties with the
hides and skins. 4th. The ouse for tanning calves skins, horses skins, is thus
prepared: Take twenty gallons of the first mild vegetable ley, to which ad
thirty gallons of soft water; the mixture being heated pour it on twenty pounds
of the best oak bark, finely powdered, draw off the decoction through a hair

page_text: strainer, and convey it to the vats; the second extract must be used in tanning
hides. 5th. In place of oak bark, either of the following substances.niay be
used with the alkaline menstruum in tanning hides or skins, videlicet: .1*t the
bark of the plane tree; 2nd, the bark of elm; 3rd, the bark of beech; 4th, the
bark of poplar; 5th the bark of horse chesnut; 6th the bark of willow; 7th, the
bark of alder; 8th. sumach; 9th, oak sawdust; 10th, oak leaves; .11, .walnut
rinds; 12, tormental root; 13th sweet broom, dried and pulverized. The
astringent properties of these substances may be extracted either by decoction
or infusion in the said alkaline ley, which ley should be more or less caustic in
proportion to the tenacity of the substance.
Fourthly. The manner of concentrating the astringent liquor:-1st. This
I perform by distillation thus: I take a portion of the liquid extract of either
of the above vegetable substances, made either by decoction or infusion, in one
or other of the said alkaline menstruums, or in pure water, which extract
being put into a retort of wood or stone, or fictile ware, and a heat applied
thereto sufficient to make it boil, the astringent matter will rise and pour out
copiously into the receiver; when the liquor begins to come out clear, the
residuum must be taken out and a fresh supply of the extract put into the
retort. The distillation made from an infusion or decoction of oak bark in
water, or very weak vegetable ley, I use for tanning of the skins of horses,
calves, sheep, goats, &c. 2nd. Or, take of either of the most tenacious vegetable
substances above named one pound, and let it steep four or five hours in a quart
of the caustic vegetable alkaline ley before mentioned, or in a quart of dilute
solution of liver of sulphur; put the mixture into a retort and perform the
distillation as before, taking care to add fresh ley from time to time till the
vegetable substance yields no more astringent matter. The strongest hides
may be tanned in this distillation effectually in a very short time. Thus the
astringent property of several tons weight of bark, and other vegetable sub-
stances proper for tanning, may be condensed into a small compass, to the great
convenience of inland carriage and exportation. A sufficient quantity of the
menstruum or soft water must be added to reduce it to the proper strength for
tanning.
Fifthly, and lastly. The manner of combining the astringent particles of
the ouse with hides and skins:-1 The hides, whether of oxen, cows, or
steers, and the skins of horses, calves, goats, seals, &c., must, in the first place,
be deprived of all extraneous matter, and perfectly depurated in the manner.
generally practised. The next operation is the swelling of them, ⚫ upon
which depends in a great measure their speedy and effectual transmutation into
leather.
This operation is performed, according to my Invention, in the

page_text: following manner:-Take twenty pound of chrystalized alum, finely powdered,
and dissolve it in thirty gallons of warm water; let the mixture be well stirred,
and, before it cools, pour it into a vat or cistern in which is put twenty gallons
of the first vegetable ley. The hides are immersed in this liquor for the space of
fifteen or twenty hours, or until their pores be sufficiently dilated, and an alu-
minous mordant lodged therein. After this they are immersed in a vertical or
horizontal position in the tanning vats, with the ouse milk warm; the astrin-
gent matter being attracted by the mordant, soon quits the other principles to
which it was united, and becomes permanently combined with the hides. Tho
residuum is then discharged from the vats, and a fresh ouse admitted in its place,
stronger than the first, and after this a third ouse, still stronger, and so on till the
hides are perfectly tanned. As this process is very expeditious the workmen
must pay more than ordinary attention to the manipulation. There is very little
danger, however, of corrugation taking place, which happens in common when
the pores of the hides are not sufficiently saturated with the astringent matter.
2nd. As a substitute for alum, add one pint of vitriolic acid to fifty gallons of
the caustic vegetable ley, prepared as directed in the second article of the
second section. This liquor may be used instead of the above for swelling
the hiles, and as a inordant. 3rd. A portion of either of these liquors, diluted
with an equal portion of water, will answer for swelling and preparing the
skins for the action of the ouse. Or, if the skins be swelled with lime in the
common.mode, a dilute solution of the said vegetablo ley may be substituted
for pidgeon's dung as an emollient.
With respect to the relative degrees of strength requisite for the ouse for
tanning of hides and skins, no specific rule can possibly be laid down. Let it
suffico to say, that the strength of the tan liquor must be proportioned to the
quality of the materials intended to be immersed in it, and the time they have
been subject to its action: 4th. When the hides are found to be sufficiently
tanned they are suspended over the vats till all the superabundant liquor has
drained. After this they are carried to the drying loft, and rubbed on both
sides with as much oil as they can imbibe, from time to time; or they may be
immersed at different times in oil during the process of tanning, or after they
are brought to the drying loft, and then prepared in the usual way for the
market.
For the skins, one immersion in oil, or one cont of the unction rubbed on
both sides with a sponge after they are tanned, will be. suflicient. The appli-
cation of oil in this operation is of the utmost importance to the quality of the
materials: it neutralizos the alkali with which they are impregnated. forming in
the pores of the leather a kind of soapy matter, which, incorporating with tho

page_text: astringent matter, forms an indissolvable mass that renders the sole leather at
once solid, durable, and in a manner impervious to water, and gives to the upper
leather that pliability and toughness which constitutes its superior excellence.
According to the method above described I have tanned pieces of the skins of
calves and of cows into leather, admitted to be of the best quality, in a very
short space of time. The latter took from twelve to sixteen days-the former
from two to three days.
In witness whereof, I, the said James Murphy, have hereunto set my
hand and seal, this Twenty-sixth day of July, in the year of our Lord
JAMES MURPHY. (L.S.)
AND BE IT REMEMBERED, that on the Twenty sixth day of July, in the
thirty-seventh year of the reign of His Majesty King George the Third, tho
said James Murphy came before our said Lord the King in His Chancery,
and acknowledged. the Instrument aforesaid, and all and every thing therein
contained and specified, in form above written.. And also the Instrument
aforesaid was stamped according to the tenor of the several Statutes made in
the sixth year of the reign of the late King and Queen William and Mary of
England, and so forth, and in the seventeenth, twenty-third, and thirty-seventh
years of the reign of His present Majesty King George the Third.
Inrolled the Twenty-sixth day of July, in the year last above written.