DYEING. 
tion of till, but in smaller proportion than 
for dyeing scarlet. To render the crimson 
deeper and give it more bloom, archil and 
potash are frequently used, but this bloom 
is extremely fugacious. 
To produce a crimson from a scarlet, the 
alkalies, alum, and earthy salts are used, 
all of which have this effect. Crimson is 
the natural colour of the cochineal, and to 
produce it from a stutf dyed scarlet, the 
stuff is boiled for an hour in a solution of 
alum, the strength of which is to be regu- 
lated by the depth of shade required. 
Of dyeing Silk red. 
The red colour obtained from madder 
does not possess sufficient brightness for 
silk ; one of the best processes for its use is 
the following of M. Guhliche : for every 
pound of silk, four ounces of alum and one 
of solution of tin are to be mixed with 
water ; when the liquor has become clear 
it is decantetl, and the silk is soaked in it 
for twelve hours, after which it is immersed 
in a bath of half a pound of madder to each 
pound of silk, softened by boiling with an 
infusion of galls in white wine. The bath 
is to be kept moderately hot for an hour, and 
then made to boil for two minutes. The 
silk is then to be taken out, washed in a 
stream of water, and dried in the sun. The 
colour thus obtained is very permanent. 
By leaving out the galls it is clearer. 
Crimson produced on silk by cochineal 
is called grain crimson, to distinguish it 
from a colour called false crimson, dyed 
with Brazil wood. For tlie grain crimson, 
the silk being well cleansed from soap at 
the river, is to be immersed for a night in 
alum liquor of the full strength ; it is then 
to be washed, and twice beetled at the 
river. The bath is prepared by filling a 
long boiler two-thirds with W'ater, to which 
are added, when it boils, from half an ounce 
to two ounces of powdered white galls for 
every pound of silk. When it has boiled 
for a few moments, from two to three 
ounces of cochineal, pow'dered and sifted, 
are put in for every pound of silk, and after- 
wards one ounce of tartar for every pound 
of cochineal. When the tartar is dissolved, 
one ounce of solution of tin is added for 
every ounce of tartar. Macquer recom- 
mends this solution of tin to be made by 
dissolving six ounces of fine grain tin, wdtli 
two ounces of sal ammoniac, in a pound of 
nitric acid, diluted with twelve ounces of 
water. When these ingredients are mixed 
togetlrer, the boiler is to be filled with cold 
water, the proportion of which, for every 
pound of silk is about eight or ten quarts. 
In this bath the silk is to be immediately 
immersed, and turned on the winch till it 
appears of an unifortn colour ; the fire is 
then encreased, and the bath is kept boiling 
for two hours, taking care to turn the silk 
occasionally ; the fire is afterwards put 
out, and the silk immersed in the bath, 
where it is suffered to remain a few hours 
longer ; it is then taken out, washed at the 
river, twice beetled and dried. 
To obtain other shades of red, the above 
processes must be varied. If, after the silk 
has been w'rung out of the solution of tin, 
it is steeped for a night in a cold solution 
of alum, in the proportion of one ounce to 
a quart of water, wrung, dried, then washed 
and boiled with cochineal, it will appear of 
a pale poppy colour. But a fine poppy-red 
may be procured by steeping it tw'elve 
hours in the solution of tin, diluted with 
eight parts of w'ater, then leaving it all night 
in the solution of alum, after which it is to 
be washed, dried, and passed through two 
baths of cochineal, taking care to add to 
the second bath a small quantity of sulphu- 
ric acid. 
The colour that comes nearest to scarlet 
has been produced on silk, by first dyeing it 
crimson and then dyeing it with carthamus, 
and afterw'ards submitting it to a yellow 
bath without heat. The colour thus given 
is very fine, but the dye of carthamus is not 
permanent. In Dr. Bancroft’s process, the 
silk is soaked for two hours in a solution of 
tin, in the murio-sulphuric acid, after which 
it is wrung out and dried partially. It is 
then to be dyed in a bath prepared with 
four parts of cochineal and three of quer- 
citron bark. In this way a colour approach- 
ing to scarlet is obtained. To give the 
colour more body, the immersion may be 
repeated in the solution of tin, and in the 
dyeing bath : the brightness of the scarlet is 
increased by the addition of carthamus. A 
lively rose colour is produced by omitting 
the quercitron bark, and dyeing with tho 
cochineal alone. 
Of dyeing Cotton and Linen red. 
To dye cotton and linen red, madder is 
used ; which cotton attracts more strongly 
than linen. The madder-red of cotton is 
distinguished into two kinds, the one is call- 
ed simple madder-red; the other, which 
is much brighter, is called Turkey, or 
Adrianople red. 
The process used at Rouen for the sim- 
