DYEING. 
After the dyeing is finished, the silk is 
srinced, by taming and shaking it in a vessel 
of cold water. 
Silk when dyed is extremely harsh ; to 
soften it a solution of four or five pounds of 
soap to every hundred pounds of silk is 
poured through a cloth into a large vessel 
of water ; being well mixed, the silk is put 
in, and left about a quarter of an hour, after 
which it is wraug out and dried. 
When raw silk is dyed, the galling is per* 
formed with cold liquor, to preserve its na- 
tural gum, and the elasticity which it causes. 
If the gall liquor is vreak, the silk is left in 
it for several days ; liquor that has been 
employed for other silk is generally used, 
and silk which has naturally a yellow hue is 
preferred. The raw silk thus prepared is 
dyed in the cold bath ; it takes the dye 
readily, and the water in which other silk 
has been rinced suffices to communicate it, 
if sulphate of iron be added. It requires 
more or less time to lie in the rincings, ac- 
cording to their strength ; sometimes three 
or four days are necessary, after which it is 
washed, and beetled once or twice ; but not 
wrung, that its elasticity may not be injured. 
It may be dyed more speedily by shaking 
it over in the cold bath after galling, and 
then airing it, and repeating tl)ese opera- 
tions a few times ; after which it is to be 
washed and dried as above. 
Macquer describes a more simple pro- 
cess, with which they dye velvet black, at 
Genoa ; it is as follows ; 
For an hundred pounds of silk, twenty 
pounds of Aleppo galls, in powder, are to be 
boiled an hour in a sufficient quantity of 
water. The bath is then left to settle till 
the galls have fallen to the bottom, when 
they are taken out, and two pounds and a 
half of English vitriol of iron, twelve pounds 
of iron filings, and twenty pounds of gum, 
are put into a copper cullender with two 
handles, and immersed in the bath; the 
cullendbr is supported by sticks, that it may 
not touch the bottom, and an hour is al- 
lowed for dissolving the gum, which is oc- 
casionally stirred. If all the gum be dis- 
solved m that time, three or four pounds 
more may be added. The cullender is only 
removed during the dyeing, and is put in 
again after it ; the copper is kept hot the 
whole time, but not suffered to boil ; the 
silk is galled with one-third of Aleppo galls, 
and left in the liquor six hours the first 
time, and twelve the second. The rest of 
the process is conducted in tlie common 
method. Thb gum is useful to keep the 
dye suspended in the liquor; but, it is pro- 
bable, a smaller quantity might answer. 
As galls are expensive, the following me- 
thod has been used to lessen their consump- 
tion. The silk, after being boiled and 
washed in the river, is prepared by im- 
mersing it in a strong decoction of walnut 
peels till the colour is exhausted ; it is then 
wrung, dried, and again washed in the river ; 
after which it is left in a solution of two 
ounces of verdegris for every pound of silk, 
in. cold water, for two hours, and then dip- 
ped in a strong decoction of logwood, which 
gives it a blue ground; it is then wrung 
out, dried, and washed in the river. The 
black bath for it is prepared by macerating 
two pounds of galls and three of sumach in 
twenty-five gallons of water, over a slow 
fire, for twelve hours; after straining, 
three pounds of sulphate of iron and as much 
gum arabic are dissolved in it. In this solu- 
tion the silk is dipped at two different times, 
left two hours in the bath each time, and 
aired and dried after each dipping; it is tlien 
beetled twice at the river, dipped again, 
and left in the bath four or five hours; 
drained, dried, and again beetled twice as 
before. The heat of the bath must not 
exceed 122 Fahrenheit. Before each of 
the last dippings, half a pound of sulphate 
of iron, and as much gum arabic, should be 
added. Some think that the galls are only 
added to increase the weight, and that the 
sumach is sufficient for the dye. 
Of dyeing Cotton and Linen black. 
Cotton and linen do not take a black tiiat 
will resist soap. The weakness of their af- 
finity for iron renders a solution of it neces- 
sary, in dyeing them, in some acid, to which 
it has less attraction than to the sulphuric. 
This solution is prepared with iron and 
vinegar, or alegar from small beer or fer- 
mented worts, according as the country 
where the process is carried on affords them 
cheapest. (Pyrolignous acid, or the acid 
liquor procured in distilling spirits of tur- 
pentine, has also been used for the same 
purpose with success.) Pieces of old iron 
are thrown into the acid liquor, and they 
are allowed to remain in it six weeks or 
two months before it is used, that it may 
be fully saturated with the iron. This so- 
iution is called iron liquor in this country. 
The process for dyeing linen and cotton 
thread black at Rouen is the following. 
It is first dyed sky blue ; then wrung out 
and dried, (a deep blue is thought to be 
better) ; it is next galled, using four ounces 
Pp 2 
