i.53 D Y 
come weakly acidulated : it is to be again turned in it on 
the Ikein dicks, or wound upon the winch when in the 
piece; in this way the -colour becomes more lively, and 
fixes better ; the cotton ntuft then be walked flightly, and 
dried by means of a dove. 
The new method of dying cotton yellow, as recom¬ 
mended by Dr. Bancroft, is much more advantageous, 
and yields permanent and beautiful colours at a finaller 
expence. The mordant he ufes is acetit of alumina, 
prepared by diflolving one part of acetit of lead, and three 
parts of alum, in a diffident quantity of water.' This 
folution ffiould be heated to the temperature of ioo°, the 
cloth diould be foaked in it for two hours, then wrung 
out and dried. The "foaking may be repeated, and the 
cloth 3gain dried as before. It is then to be barely wetted 
with lime-water, and afterwards dried. The foaking in 
the acetit of alumina may be again repeated ; and if the 
ffiade of yellow is required to be very bright and durable, 
the alternate wetting with lime-water, and foaking in the 
mordant, may be repeated three or four times. By this 
contrivance a fufficient quantity of alumina is combined 
with the cotton, and the combination is rendered more 
permanent by the addition of lime. The dying bath is 
prepared by putting twelve or eighteen parts of querci¬ 
tron bark, (according to the depth of the lhade required,) 
tied up in a bag, into a fufficient quantity of cold water. 
Into this bath the cotton is to be put, and turned round 
in it for an hour, while its temperature is gradually raifed 
to about 120°. It is then to be brought to a boiling heat, 
and the cotton allowed to remain in it after that only a 
few minutes. If it be kept long at a boiling heat, the 
yellow acquires a ffiade of brown. 
Another way of dying cotton very permanent yellows, 
would be to imitate the method adopted for dying cot¬ 
ton in the eaft. That method is indeed exceedingly 
tedious, but it might be very much fliortened by care¬ 
fully attending to the ufes of the ingredients. The e.Ten- 
tial part of the procefs is to caufe thS alumina to com¬ 
bine in fufficient quantity with the fabric, and to adhere 
with fufficient firnmef’s to enfure a permanent colour. 
This is accompliffied by ufing three mordants; firft oil, 
then tan, and laftly alum. The combination of thefe 
three fubftances produces a mordant which enfures a very 
permanent colour. The cotton is firft foaked in a bath 
conipofed of a fufficient quantity of oil, and mixed with 
a weak folution of foda. Animal oil feems to anfwer bed 
for the purpofe. Vogler found that glue anlwered ex¬ 
tremely well. The foda ffiould be cauftic: in that date 
it combines with the oil, and enables the cotton to abforb 
it equally. It is then, after being walked, put into an 
infufion of nut-galls, (the whiter the better.) The tan 
combines with the oil, while the gallic acid carries off 
the alkali that may remain attached to the cloth. The 
infufion ought to be hot; and the cotton, after coming 
out of it, ffiould be dried as quick as podible. Care ffiould 
be taken that the quantity of galls do not exceed a jud 
proportion compared with the oil, otherwife the colour 
will be darkened. The cotton, thus prepared, is to be 
put into a folution of alum. There is a drong affinity be¬ 
tween tan and alumina ; in confequence of which, the 
alum is decompofed, and the alumina combines with the 
tan in fufficient abundance. The cotton, thus prepared, 
is to be dyed, as above deferibed, with quercitron bark. 
Mr. Chaptal, whole ingenious labours have contributed 
exceedingly to elucidate the theory of dying, has pro- 
pofed an exceedingly dimple and cheap method of dying- 
cotton a fine permanent nankeen yellow. His procefs is 
as follows : Cotton has Co drong an affinity for oxyd of 
iron, that if put into a folution of that oxyd in any acid 
whatever, it decompofes the fait, abforbs the iron, and 
acquires a yellow colour. The cotton to be dyed is 
to be put into a cold folution of fulphat of iron, of the 
fp. gr. 1-020; it is then wrung out, and put diredtly into 
a ley of potafh, of the fp. gr. i-oio, into which a folu¬ 
tion of alum has been poured till it was faturated with 
I N G. 
it. After the cotton has remained in this bath four or 
five hours, it may be taken out, walked, and dried. By 
this procefs cotton may be dyed all the different lhades 
of nankeen, by varying the proportion of the fulphat of 
iron. This colour has the advantage of not being in¬ 
jured by walking, and of being exceedingly cheap. 
To dye cotton Red, madder is the principal ingre¬ 
dient, as well as for giving many other colours by dif¬ 
ferent admixtures. The madder red on cotton is dif- 
tinguiflied into two kinds ; the one is called fimple 
madder red ; the other, which is much brighter, is called 
Turkey or Adrianople red, becaufe it comes from the 
Levant, and has feldom been equalled in briglitnefs or 
durability. The reds introduced by madder differ very 
much in briglitnefs and permanency, according to the 
proceffes employed. The great difficulty conliffs in the 
application of the mordant, which is by far the moll 
complicated of any in the whole art of dying. We are 
indebted to Mr. Vogler, of Weilburg, for fome very in- 
terefting experiments on this fubjedt. He firft confiders 
the bales or mordants, and afterwards the preparation 
of the madder bath. The firft mordant that was tried 
confided of a folution of three drachms of Roman alum 
in fourteen ounces of water. Cottons boiled for fome 
minutes in this folution, and afterwards paffed through 
the different madder baths, took a flight poppy-coloured 
red. The author obferved in this, and many other 
experiments, that Roman alum was much better than 
common alum, and gave greater briglitnefs to the colours. 
The addition of the fmalleft quantity of any kind of acid 
rendered it paler; the addition of arfenic produced no 
eft'eiffi; fiieep and cow dung, and album grecuvi , added to. 
the mordant, as alfo urine employed inftead of water to 
dilfolve the alum, contributed to ftrengthen the colour. 
Muriat of foda and ammoniacal muriat had more effect, 
but thefe falts rendered the colour more dull ; lime- 
water.adted very much in the fame way. The fubftances 
which had the belt eft'eft were gum arabic, (larch, fenu¬ 
greek-feed, and, above all, glue. The gaftric juice, and 
the ferous part of the blood of animals, aft in a manner 
finiilar to glue, and ferve to aniitialife the cotton. Thread 
and cotton may be foaked alternately in a folution of glue 
and a folution of alum, or the glue may be dilfolved 
with the alum, in the proportion of from one drachm 
and a half to four drachms, with the quantity of alum 
direfted. It is neceffary to choofe fine glue. This fub- 
ftance ufed with alum produces a more faturated colour, 
but without alum the red is of a dufky colour. It is 
alfo found that muriat and nitrat of alurrrincffiot only pro¬ 
duce a more intenle and durable red than alum, but the 
tint is pleafanter, more efpecially when the nitrat is em¬ 
ployed. In general, muriats render the colour darker, 
more faturated, and more durable. Corrofive mercurial 
muriat produces an effect of a fimilar kind. Having dif- 
folved in a ftrong ley of pot-afh as much powdered while 
arfenic as it would take up with the affiffance of heat, 
and having mixed this folution, which had been diluted 
with two parts of water, with a faturated folution of 
alum, the mixture became turbid, and of the confidence 
of jelly; it recovered its transparency on a folution of 
alum being gradually added. It was found that thread 
and cotton foaked for twelve hours in this mordant, when 
waffled and dried, received from madder a beautiful red 
colour. Thread and cotton which had been for lix hours 
in nitro-muriatic acid, and afterwards waffled and dried, 
took from madder a more beautiful and durable colour 
than that which dyers obtain from anotta; even da¬ 
maged madder, by means of this mordant, afforded a yel- 
lowilh brown, that had a ffiade very agreeable. 
This colour is capable of being changed into a poppy- 
coloured red, which may vie with the moll beautiful co¬ 
lours of this line obtained from Braiil-wood and cochi¬ 
neal, by firft foaking the fluff in a folution of alum and 
common fait, and boiling it a fecond time with madder. 
Mr. Vogler macerated for a night three drachms of pot- 
