IMPROVEMENTS IN MANUFACTURING LEATHER
Year: 1849

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Mechanical Draughtsman, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Seventeenth day of November, in the thirteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
.said Alfred Vincent Newton, Her especial license, full power, sole privilege
and authority, that I, the said Alfred Vincent Newton, my exors, adiñors,
and assigns, and such others as I, the said Alfred Vincent Newton, my exors,
.adñors, 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 mentioned, should
and lawfully might make, use, exercise, and vend, within England, Wales,
the Town of Berwick-upon-Tweed, and in all Her Majesty's Colonies and
Plantations abroad, and in the Islands of Jersey, Guernsey, Alderney, Sark,
and Man, an Invention of "IMPROVEMENTS IN MANUFACTURING LEATHER,"
being a communication from abroad; in which said Letters Patent is contained
a proviso obliging me, the said Alfred Vincent Newton, by an instrument in

page_text: writing under my hand and seal, particularly to describe and ascertain the
nature of the said Invention, and in what manner the same is to be
performed, and to cause the same to be inrolled in Her Majesty's High Court
of Chancery within six calendar months next and immediately after the date
of the said in part 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
Alfred Vincent Newton, do hereby declare that the nature of the said Invention,
and the manner in which the same is to be performed, is particularly
described and ascertained in and by the following description thereof (that is
to say):
*--
The nature of this Invention of "Improvements in Manufacturing Leather,"
as communicated to me by my Foreign Correspondent, will be clearly under-
stood from the following description thereof:-The objects designed to be
obtained by the present improvements are, the expediting of the operation,
lessening the cost of manufacture, and at the same time producing leather of
superior quality. I am not aware that these three objects have hitherto been
attained by one operation, as it appears that whenever either the duration or
expense of the operation has been diminished the leather has proved to be of
inferior quality. The above objects are fully obtained by the proposed
improvements, which are applicable to the manufacture of every kind of
leather. And in order that they may be perfectly intelligible, I will describe
the operation as applied to leather intended for currying.
I shall suppose one hundred calf skins are to be operated upon, each weigh-
ing (when in a fresh state and with the hair on) about eight pounds. These
skins having been deprived of the hair, and perfectly freed from lime
(supposing that substance to have been employed for the removal of the hair),
and having been properly dressed, are submitted to the tanning operation.
For this purpose the following ingredients are to be mixed with a quantity.of
water sufficient for their complete solution, viz, twenty pounds of the
sulphate of alumina and potash (alum), and ten pounds of chloride, of sodium.
This solution is to be poured into a vat which I shall call No. 1. Into a
second vat, which I shall call No. 2, pour a solution formed of one hundred
pounds of mimosa catechu, rich in tannin and coloring matter (supposing this
to be the substance employed in tanning). Into a third vat, which I shall call
No. 3, pour a solution of four pounds of sulphate of alumina, either alone or
in combination with two pounds of chloride of sodium. Now take one fifth
part of the contents of the vessel No. 1 (that is to say), a quantity of fluid

page_text: equal to four pounds of the sulphate of alumina and potash (alum), and two
pounds of chloride of sodium; one tenth part of the contents of the vessel.
No. 2, which would contain ten pounds of mimosa catechu; one fourth of
the contents of the vessel No. 3, equivalent to a pound of sulphate of alumina
and half a pound of chloride of sodium. Pour the whole into a large vessel
suitable for soaking the skins. This I shall call the vat A. Add a quantity
of water sufficient to cover the hundred skins above mentioned, and heat the
liquid in the vat A to about twenty-five degrees Beaumé; then take the skins
which are ready for tanning and dip them one by one in the vat A and leave
then therein. Three or four men placed round the vat, each armed with a
stick rounded at the end, must then move the skins round as near as possible
to the edge of the vat, and continue this rotary movement for about an hour,.
or instead thereof any suitable mechanical arrangement may be employed if
thought desirable. At the expiration of the hour remove the skins from thíc
vat. Next take one fifth part of the contents of the vat No. 1, equal to four
pounds of the sulphate of alumina and potash (alum), and two pounds of
chloride of sodium; one tenth part of the contents of the vat No. 2, viz, ten.
pounds of mimosa catechu; one fourth part of the vat No. 3, equal to one
pound of sulphate of alumina and half a pound of chloride of sodium. Pour
the whole into the vat A; keep its contents at a temperature of about twenty-
five degrees Beaumé; place the skins again in 'the vat, and recommence the
stirring, which is to be continued for several hours. The skins are then again
taken out, and afterwards re-immersed in the vat A, where they are allowed
to remain until the next morning. The next day remove the skins; heat
the liquor in the vat A to a lukewarm temperature; pour into it one fifth of"
the contents of the vat No. 1 (that is to say), a quantity of its contents equal
to four pounds of the sulphate of alumina and potash (alum), and two pounds
of chloride of sodium; one fifth of the contents of the vat No. 2, equivalent to
twenty pounds of mimosa catechu. Continue the soaking operation for some
hours, take out the skins, and afterwards return them to the vat A, laying them
flat in the vessel, where they must remain until the next day. If the tanning
operation is to be continued in the vat A, remove the skins at least once a day,
and before re-immersing them stir the liquor briskly and lay the skins in the
vessel as flat and evenly as possible. At the sixth or seventh day from the
commencement of the operation take the skins out and pour into the vat A.
the remainder of the contents of the vat No. 1, equivalent to eight pounds of
the sulphate of alumina and potash (alum); and four pounds of chloride of
sodium. The remainder of the contents of the vat No. 3, equal to two pounds.

page_text: of sulphate of alumina and one pound of chloride of sodium; also one fifth of
the contents of the vat No. 2, equal to twenty pounds of mimosa catechu.
Stir these together and soak the skins therein for some hours; continue the
operation, removing the skins for a few moments every day, if possible. On
the fourteenth or fifteenth day add to the contents of the vat A about two
fifths of the contents of the vat No. 2, equal to twenty pounds of mimosa catechu,
and six or seven days afterwards add the remaining two fifths, viz, twenty
pounds of mimosa catechu. At the expiration of five or six days from the
commencement of the treatment examine the skins carefully, cutting slits in
their thickest parts, in order to observe the progress of the operation. Keep
up the strength of the tanning liquor in order that the leather may not loose
its swelling or thickening so that it would sink; for this purpose a fresh dose
of mimosa catechu may be added if requisite. At the expiration of about four
or five weeks from the commencement of the operation the conversion of the
skins into leather will be completed. This may be ascertained by making
incisions in the thickest parts of the skins, which ought to be impregnated
uniformly in every part. The hides thus prepared will prove of fine color and
quality. When the operation is completed, and the skins are required to be
curried, hang them for about twenty-four hours on the frame; they will
then be ready for currying.
from.
I shall now describe another method of converting hides or skins into
leather, by which the mode ordinarily employed is not very materially departed
When about the tenth day of the operation has arrived, and the skins
have been subjected to the various successive immersions in the fluids prepared
according to the directions already given, and with the precautions and peculiar
manipulation above described, take them from the vat A, and lay them in
powdered bark, in the proportion of two or three pounds to each skin; the
powder is to be damped with a portion of the liquor from the vat A, or with
bark liquor sharpened a little. The tan pit is to be provided with a wooden
hand pump of the kind usually employed by tanners, and every two or three
days the liquor should be pumped from the bottom of the pit and allowed to
fall into it again in order to maintain a perfect mixture of the liquor, and
render it throughout as homogenous as possible. The above described opera-
tion will be the same for all soft leather, no matter whether the skins operated
upon be calf skins, goat skins, sheep skins, cow hides, heifer skins, or seal
skins. The proportions of the substances will, however, vary for different
kinds of skins as follows:-For one hundred goat skins, sheep skins, or seal
skins, dissolve in a sufficient quantity of water from eight to ten pounds of

page_text: the sulphate of alumina and potash (alum), six pounds of chloride of sodium,
and from fifty to sixty pounds of mimosa catechu. For one hundred calf skins;
each weighing (in the fresh state, and with the hair on,) about eight pounds
the proportions have been already given. For one hundred cow hides, each
weighing (in the fresh state, and with the hair on,) about forty-eight pounds,
and intended for the upper leathers of shoes and boots, the proportions will be
sulphate of alumina and potash (alum) one hundred pounds, chloride of sodium
fifty pounds, mimosa about five hundred pounds. If it be desired to, tan by
laying the skins in the tan pit, proceed as described above when speaking of
that operation, the proportion of bark to be employed being about three pounds
for every eight pounds of skins (fresh, and with the hair on). If it be
desired to tán strong leather to be curried for harness or trunk making,
for every hundred skins take from two hundred to three hundred pounds
of the sulphate of alumina and potash (alum), and about one hundred
pounds chloride of sodium (one half the quantity of chloride of sodium
may be employed, substituting therefor an equal quantity of sulphate of
soda or magnesia, if a brighter color and a firmer or harder quality of
leather be required); sulphate of alumina may, however, always be employed
for calf skin. When it is required to tan skins for the preparation of soft
leather, such as calf or goat skins, for boots and shoes, for every hundred skins
take from two to three pounds of the sulphate of alumina and potash (alum),
and an equal quantity of chloride of sodium; for every hundred cow hides from
forty to fifty pounds of sulphate of alumina and potash (alum), and one half
the quantity of chloride of sodium. (The tannin and coloring matter may be
applied in the form of liquid extract of bark, if found more convenient for
the coloring of the products). It may be here remarked that after the com-
pletion of the tanning operation the liquors employed still retain a fifth or sixth
part of their strength, and that advantage must be taken of this by diminishing
the quantity of the different ingredients in proportion, and thus utilizing the
liquor which had been before employed. The operation above described may
be divided into two distinct operations as follows:-First operation, white tan-
ning or dressing: in this case dissolve only the sulphate of alumina and potash
(alum) and the chloride of sodium; if these ingredients be employed in 'the
proportions indicated, the skins must be treated in the manner required for
dressing. Second operation, coloring, tanning, or immersion of the skins in
mimosa catechu, which must be employed in the manner and proportions above
mentioned, until the skins are completely saturated. For the manufacture of
hard leather employ.as far as possible skins unhaired when dry, as they must
not be abated. For ox hides, weighing two hundred pounds, from fourteen to

page_text: sixteen pounds of sulphate of alumina and potash (alum) must be employed;
and five per cent. of chloride of sodium; (that is to say,) supposing forty
pounds of sulphate of alumina and potash be employed, only two pounds of
chloride of sodium will be required, and from ten to twelve pounds of
mimosa catechu; place them in a flat vat, and treat them in the same manner
as is required for the manufacture of Hungary leather, having previously
soaked them only a sufficient time to produce a uniform color free from stains
or spots. When the above-described operations are completed, the skins are
to be left in the above-mentioned solutions, and at the expiration of seven or
eight days sixty pounds of mimosa catechu in solution are to be added. At
the end of about twenty days, during which time the skins must be occasionally
raised, they must be laid in the tanpit as already mentioned. The quantity
of bark employed will be about thirty pounds for each skin. I would observe,
in conclusion, that the operations above described being of novel character,
both in science and manufacture, I shall call the process for treating soft
leather Megisso-tanning, and for hard leather Hongroyo-tanning.
Having now described the nature of the Invention communicated to me by
my Foreign Correspondent, I wish it to be understood that I claim under the
above in part recited Letters Patent the manufacture of leather by effecting
the tanning operation in the following manner, viz:-By employing substances
which act immediately upon the albuminous matter of the skins (such as sul-
phate of alumina, sulphate of alumina and potash (alum), chloride of sodium,
chloride of potassium, the sulphates of soda, potash, or magnesia, chloride of
zinc, or of aluminium, &c., either alone or in mixture, and perfectly neutral,
sulphite of soda may also be employed) in combination with substances con-
taining tannin, and intended to act upon the gelatine of the skins (such as
mimosa catechu, the bark of various kinds of oak, and also their leaves and fruit,
the bark of the beech, poplar, chestnut, birch, maple, spurge laurel, sumach, &c.,
and in fact any substance containing tannin), which matters containing tannin
must be employed in proportions varying according to their known richness,
taking as a standard mimosa catechu of good quality, which contains about
fifty per cent. of tannin, and which is to be employed in the proportions set
forth in the body of the Specification.
In witness whereof, I, the said Alfred Vincent Newton, have hereunto set
my hand and seal, this Seventeenth day of May, in the year of our
Lord One thousand eight hundred and fifty.
(L.S.) A. V. NEWTON.

page_text: AND BE IT REMEMBERED, that on the Seventeenth day of May, in
the year of our Lord 1850, the aforesaid Alfred Vincent Newton came before
our said Lady the Queen in Her 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.
Enrolled the Seventeenth day of May, in the year of our Lord One
thousand eight hundred and fifty.