IMPROVEMENT IN THE TREATMENT OF WOOL
Year: 1855

page_text: LETTERS PATENT to Thomas Barrows, of the State of Massachusetts, of
the United States of America, for the Invention of "IMPROVEMENT IN THE
TREATMENT OF WOOL."
Sealed the 26th November 1855, and dated the 5th June 1855.
PROVISIONAL SPECIFICATION left by the said Thomas Barrows at the
Office of the Commissioners of Patents, with his Petition, on the 5th
June 1855.
I, THOMAS BARROWS, of the State of Massachusetts, of the United States of
America, do hereby declare the nature of the Invention or "IMPROVEMENT IN
THE TREATMENT OF WOOL" to be as follows:-
After wool has been cleansed in the usual way, by washing in warm brine,
or soap and water, or weak alkaline solutions, there remains at the points
where the imbrecations of the fibres are most close a certain portion of grease
or "yolk" combined with an earthy base, which neither of the agents above
named will remove; and this substance usually passing all the operations of
manufacturing and dyeing, can be found in the finished cloths, preventing the
softness of carefully purified wool from being observable in the finished
cloths.

page_text: The locks of the wool and portions of every fleece from the adhesion of
manure or other causes present curled and yellow colored ends, called "dead
wool," which do not readily receive dyes, a fact which is more especially
evident in dyeing with indigo. The most carefully cleansed wool of any fleece
takes under the same conditions of treatment various shades of color, some
portions even remaining nearly white. It has been the general impression
among wool manufacturers that the parts of the fleece which have thus
become "dead wool" were oxidized and changed in a manner preventing
them from being restored to their former condition or natural state. I
find, from experiments made on many varieties of wool, both foreign and
domestic, that the property of deadness and general injury is due to a
reductive or hydrogenating effect, often the result of putrefactive fermen-
tation, and that by proper oxidizing agents the natural condition can be
restored.
Having thus premised, I will proceed to detail the steps of a method by
which wool can be rendered much softer than usual, and prepared to receive
dyes quite uniformly throughout the fleece. Two hundred pounds of sorted.
fleece wool having been cleansed will, when dried weigh about 150 lbs. In
cases where the wool loses less weight in the scouring operation, I have
regard to this loss in proportioning the quantity of the oxidizing agent
employed, using so much-more of the latter as will make it equal for given
weight of clean dry wool. The wet wool, resulting from two hundred pounds of
fleece wool which has been-scoured by brine or soap or in any ordinary manner,
is to be passed after a careful rincing into a bath prepared as follows:-In a
scouring tub of wood, fitted as usual for heating by steam, and containing so
much water as will cover the wool, I dissolve six pounds of saltpetre, nitrate
of soda, chlorate of potash, or other oxidizing salt, raising the temperature of
the bath to 150° or.
160° Fahrenheit, Into this bath the rinced wool from
two hundred pounds of fleece wool is passed, and with occasional moving by.
the "pole" is allowed to repose thirty or forty minutes: it is next to be
removed to the extractor," when the water is, expelled, and afterwards dried
as usual. 'Successive parcels, each resulting from two hundred pounds of fleece
wool are thus to be passed through the öxidizing bath, an addition of two
pounds of the saltpetre or other oxidizing salt being made before each parcel
of wool is placed in it. Very bad wool, or that containing much "dead wool,"
requires longer time in the baths, practice enabling any one to apportion time
to quality.
The affect of this bath of a hot solution of saltnefre is to produce a decom-
>

page_text: 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 OR IMPROVE
MENT, WHEREBY WOOL MAY BE NOT ONLY CLEANSED, SOFTENED, AN PREPARED IN
AN IMPROVED MANNER FOR PERFECTING THE FINISH OF WOOL GOODS, BUT ENABED TO
TAKE DYES UNIFORMLY AND TO GREAT ADVANTAGE," upon the condition [amongst
others] that I, the said Thomas Barrows, by an instrument in writing under
my hand and seal, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same is 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 Thomas Barrows, do hereby declare that
the nature of my said Invention, and the manner in which the same is to be
performed, to be particularly described and ascertained in and by the following
statement (that is to say):
=
..After wool has been cleansed in the usual way, by-washing in warm brine,
or soap and water, or weak alkaline solutions, there remains at the points
where the imbrications of the fibres are most close a certain portion of grease
or "yolk" combined with an earthy base, which neither of the agents above
named will remove; and this substance usually passing all the operations of
manufacturing and dyeing, can be found in the finished cloths, preventing the
softness of carefully purified wool from being observable in them. The locks
of the wool and portion of every fleece, from the adhesion of manure or other
causes, present curled and yellow ends, called "dead wool," which do not
readily receive dyes, a fact which is more especially evident in dyeing with
indigo. The most carefully cleansed wool of any fleece takes, under the same
conditions of treatment, various shades of color, some portions even remaining
nearly white. It has been the general impression among wool manufacturers
that the parts of the fleece which have thus become "dead wool "were oxidized
and changed in a manner preventing them from being restored to their former
condition or natural state. I find, from experiments made on many varieties
of wool, both foreign and domestic, that the property of deadness and general
injury is due to a reductive or bydrogenating effect, often the result of putre-
factive fermentation, and that by proper oxidizing agents the natural conditions
can be restored.
Having thus premised, I will proceed to detail the steps of a method by
which wool can be rendered much softer than usual, and prepared to receive
dyes quite uniformly throughout the fleece. Two hundred pounds of sorted fleece

page_text: wool having been cleansed, will when dryed weight about one hundred and fifty
pounds. In cases where wool loses less weight in the scouring operation, I have
regard to this loss in proportioning the quantity of the oxidizing agent employed,
using so much more of the latter as will make it. equal for a given weight
of clean dry wool. The wet wool; resulting from two hundred pounds of fleece
wool which has been scoured by brine or soap, or in any ordinary manner, is to
be passed after a careful rinsing into a bath prepared as follows:-In a scouring
tub of wood fitted as usual. for heating by steam, and containing so much
water as will cover the wool, I dissolve six pounds of saltpetre, nitrate of soda,
chlorate of potash, or other oxidizing salt, such as nitrate of ammonia, or an
equivalent which will cause the deoxodized wool to receive oxygen in the air,
raising the temperature of the bath to 150° or 160° Fahrenheit. Into this
bath the rinsed wool from two hundred pounds of fleece wool is passed, and
with occasional moving by the "pole" is allowed to repose thirty or forty
minutes; it is next to be-removed to the "extractor," when the water is
expelled, and afterwards dried as usual. Successive parcels, each resulting
from two hundred pounds of fleece wool; are thus to be passed through the
oxidizing bath, an addition of two pounds of the saltpetre or other oxidizing
salt being made before each parcel of wool is placed in it. Very bad wool, or
that containing much "dead wool," requires longer time in the bath, practice
enabling any one to apportion time to quality. The effect of this bath of a hot
solution of saltpetre is to produce a decomposition of the earthy soap existing
in the closest interstices between the lapping of the scales or imbrications of
the fibres, a soluble earthy salt being formed with the acid of the oxidizing
salt, at the same time that the alkali of this salt unites to the organic acid of
the soap or yolk to form another soluble or miscible salt, so that the matter is
mostly removed. The saltpetre or other oxidizing salt left in the wool as it
dries also acts on any remaining portion of insoluble soap to render it soluble
in subsequent operations, and experiments show in the bath liquor the presence
of the changed salts. Another effect of the oxidizing bath explains why I use
oxidizing salts instead of saline compounds of another class, such as sal
ammoniac, which will partially remove the earthy soap; it is a specific oxidizing
or changing effect on the "hurls," "dead" ends, or "dead" wool, which is
thus produced in the use of oxidizing salts. The "dead" wool after treatment
in the oxidizing bath will take the dyes generally as well as the "natural"
wool; and so well marked is this effect, that I can produce it in the mordanting
bath, or even dye bath, on wool which has not been treated in the oxidizing
bath, but prefer the use of the latter in all cases. The wool to be dyed need

page_text: not be dried from the oxidizing bath, it being sufficient to extract the water or
allow the wool to drain over night.
What I claim as my Invention or discovery is, the application of nitre or
any of its equivalent salts as set forth to wool in a warm bath, for the purpose
of restoring the wool when it has become changed, as well as for cleansing,
softening, and preparing it, so as to better adapt it to recieve dyes, and being
finished into fabrics.
In testimony whereof, 1 have hereunto set my signature and seal, this
Fifth day of October, A.D. 1855.