IMPROVEMENTS IN THE PROCESS OF DYEING WOOL AND WOOLLEN FABRICS YELLOW
Year: 1834

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HERMAN
HENDRIKS, of the Strand, in the County of Middlesex, Gentleman, send
greeting.
WHEREAS His present most Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Eighth day of April, in the fourth year of His reign, did,
for Himself, His heirs and successors, give and grant unto me, the said
Herman Hendriks, His especial licence, full power, sole privilege and
authority, that I, the said Herman Hendriks, my exors, adors, and
assigns, or such others as I, the said Herman Hendriks, my exors, admors,
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 might make, use, exercise, and vend, within England, Wales,
and the Town of Berwick-upon-Tweed, the Invention of "IMPROVEMENTS
IN THE PROCESS OF DYEING WOOL AND WOOLLEN FABRICS YELLOW," communicated
to me by a certain Foreigner residing abroad; in which said Letters Patent
is contained a proviso that I, the said Herman Hendriks, shall cause a
particular description of the nature of the said Invention, and in what
manner the same is to be performed, to be inrolled in His said 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
Herman Hendriks, do hereby declare that the nature of the said Invention,

page_text: and the manner in which the same is to be performed, are described and
ascertained as follows, that is to say :-
The Improvements in Dyeing Wool and Woollen Fabrics Yellow consists
in the application of the process of double decomposition of the cromate of
potash or the bicromate of potash or the cromate of soda and a soluble salt
of lead to the process of dyeing wool and woollen fabrics yellow. But in order
that the Invention may be fully understood, I will now describe the process to
be pursued.
Prepare the following baths, say No. 1. with the acetate of lead (or any
other soluble salt of lead) of the specific gravity of about two degrees of
Beaume's arcometer for salts, and this bath is to be heated by the contact
of steam, not condensed, to about one hundred or one hundred and five degrees
of Fahrenheit.
Bath No. 2 to be prepared with the cromate of potash or the bicromate of
potash (the cromate of soda will answer equally well) of the specific gravity
of about three degrees of Beaume's areometer for salts, and this bath is to be
heated by the same means as No. 1 to about one hundred and sixty degrees
Fahrenheit.
Bath No. 3 consists of water which may be used at the ordinary temperature
or a little warmer, say sixty to seventy degrees of Fahrenheit.
Bath No. 4 consists of water slightly acidulated with the acetate of lead, so
as only to be of a very feight acid taste.
The baths Numbers 1 and 2 will serve for a great many operations on
adding to them such quantity of the matter with which they are formed as is
requisite to keep them in the state of specific gravity before mentioned, but
whenever it may be desired to empty the vessels, the contents of the two
vessels or baths may be mixed together, and the deposit therefrom will be the
cromate of lead, known as an article of commerce for painting, &c., and when
it is necessary to change the waters in baths Numbers 3 and 4, the cromate of
lead will also be obtained by mixing them together, and if necessary to
cause a quick deposit a small quantity of the liquid contained in baths Nos. 1
and 2, (both or either), may be added (experience will be the best guide as
regards the quantity of either or both these liquids). The baths Numbers
3 and 4 are only used for economy, and where it may be found inconvenient
to place them they may be dispensed with, and the material dyed may be
washed in water in any convenient manner, such as is ordinarily resorted to in
dyeing by the ordinary methods.
Process to be pursued for dyeing wool in the flock or fleece:-The baths
shu'd be formed in round vessels. For cloth stuffs, &c. in the piece, the

page_text: baths Numbers 1 and 2 should be forined in oblong square vessels, with a
roller near the bottom under which the cloth stuff, &c. must pass, and from
thence to pressing rollers placed on the upper part of the vessels to distributo
and equalise the liquid and express it as much as possible on passing from the
one bath to the other.
For skeins, the baths may be formed in any vessels, for instance, the round
ones intended for wool will answer.
Process of dyeing wool in the flock or fleece.-After the wool has been
perfectly freed from grease, and well washed in plenty of water, by the ordinary
means, it should be placed in an open circular vessel pierced with holes all
round and at the bottom (the vessel to be made of a corresponding size with
those in which the baths are formed, that is to say, so much smaller as is
necessary to admit of its entering those vessels with facility), and by means
of a crane or pulley or any other convenient method the vessel containing the
wool should be lowered into the bath No. 1, and remain there eight or ten
minutes, during which time it is adviseable to raise and descend the vessel
once or twice, then allow the wool to drain for some few minutes, and after-
wards pass it into bath No. 2 in the same manner, where it should remain
for about the same time as in No. 1; and after being raised out of the liquid,
and allowed to drain for a few minutes, the wool is to be passed in the same
way into bath No. 3 to be washed, from thence to No. 4 for the same purpose,
and afterwards to be washed in a loose state in plenty of cold water. The
latter operation should be resorted to immediately after the use of the bath
No. 2 if Nos. 3 and 4 are not used. The wool after having been passed into
the two first baths will generally have required the desired intensity of color,
if such should not be the case, the operation must be repeated, and when it is
desired to obtain lighter colours the baths Nos. 1 and 2 are to be prepared
of a less specific gravity than has been stated.
Process of dyeing in the piece.-The baths being prepared as directed, the
cloth, stuff, &c. is to be passed by means of a small cord under the roller near
the bottom of the vessel containing the liquid which forms the bath No. 1
having passed this roller, the cloth, &c. is conducted between the pressing
rollers, and, by the application of a pinion on the end of one of such pressing
rollers, the cloth will be passed regularly through them, and then into bath
No. 2, where it should be treated in the same manner, and from thence to
baths Nos. 3 and 4 (if they are intended to be used). The cloth, &c. is then
to be washed and cleansed with fullers' earth in the same way as is resorted to
by dyers when operating by any other process, or it may be passed through a
soap bath, such as is recommended for skeins.