151 
D Y 1 
fuperfede the ufe of that plant. The method of ufing 
each of thele dye-lhiffs is nearly the fame. 
Wool may be dyed yellow by the followin gprocefs : 
Let it be boiled for an Hour, or more, with about one- 
iixth of its weight of alum, dilfolved in a fufficient quan¬ 
tity of water. It is then to be plunged, without being 
rinced, into a bath of warm water, containing in it as 
much quercitron bark as equals the weight of the alum 
employed as a mordant. The cloth is to be turned 
through the boiling liquid till it has acquired the in¬ 
tended colour. Then a quantity of clean powdered chalk, 
equal to the hundredth part of the weight of the cloth, 
is to be ftirred in, and the operation of dying continued 
for eight or ten minutes longer. By this method a deep 
and lively yellow may be given, fully as permanent as 
weld yellow. 
For very bright orange, or golden yellow, it is necef- 
fary to have recourfe to the oxyd of tin as a mordant. A 
fine orange yellow may be given to woollen cloth, by 
putting, for every ten parts of cloth, one part of bark 
into a fufficient quantity of hot water; after a few mi¬ 
nutes, an equal weight of murio-fulphat of tin is.to be 
added, and the mixture well llirred. The cloth acquires 
the wifhed-for colour in a few minutes when brilkly turn¬ 
ed in this bath. The fame procefs will ferve for pro¬ 
ducing a bright golden yellow ; only fome alum mull be 
added along with the tin. For the brighteft golden yel¬ 
low, the proportions fufficient for dying one hundred parts 
of cloth are, ten parts of bark, feven parts of murio-ful¬ 
phat of tin, and five parts of alum. All the poffible 
lhades of golden yellow may be given to cloth merely by 
varying the proportion of the ingredients according to the 
ffiade. 
lit order to give the yellow that delicate green fliade 
fo much admired for certain purpofes, the fame procefs 
may be followed, only tartar mull be added in different 
proportions according to the (hade. Thus to dye one 
hundred parts of cloth a full-bright yellow, delicately 
inclining to green, eight parts of bark, fix of murio-ful¬ 
phat, fix of alum, and four of tartar, are to be employed. 
The tartar is to be added at the fame time with the other 
mordants. If the proportion of alum and tartar be in- 
creafed, the green ffiade is more iively : to render it as 
lively as poflible, all the four ingredients ought to be 
employed in equal proportions. As tliefe fine lemon- 
yellows are generally required only pale, ten parts of 
each of the ingredients will be fufficient to dye about 
three hundred parts of cloth. By adding a fmall pro¬ 
portion of cochineal, the colour may be railed to a fine 
orange, or even'an aurora. 
Of RED. 
The principal colouring matters employed in dying 
red are, kermes, cochineal, archil, madder, carthamus. 
and Brazil wood. In different parts of Alia and the 1 'outh 
of Europe, there grows a fmall fpecies of oak, to which 
Linnaeus gives the name of quercus cocciferci. On this oak 
relides a fmall infeef, of a reddilh brown colour ; in com¬ 
merce it is known by the name of kermes. This inlett is 
a fpecies of coccus : Linnaeus called it coccus ilicis. Thefe 
infeeds are gathered in the month of June, when the fe¬ 
male, which alone is ufeful, is levelled with eggs. They 
are lleeped for ten or twelve hours in vinegar to kill the 
young infefts contained in the eggs, and afterwards dried 
on a linen-cloth. In this ftate they are fold to the dyer. 
Kermes readily gives out its colouring matter to water 
or alcohol. It was much uled by the ancients in dying; 
the colours which it produced were highly elteemed, be¬ 
ing inferior in price only to their celebrated purple. The 
colour which it communicates to cloth is exceedingly 
permanent, but being far inferior in beauty to thole 
which may be obtained from cochineal, it has been but 
little employed by dyers lince that Iplendid pigment 
came into common ufe. 
Cochineal is likewil'e an infe£J, a fpecies of coccus. 
N G. 
Linnaeus diftinguiffies it by the name coccus caSli. It in¬ 
habits different fpecies of cadti, but the mod: perfect va¬ 
riety is confined to the cactus coccinillifcr. The cochineal 
infect was firlt dil'covered in Mexico ; the natives had 
employed it in their red dyes before the arrival of the 
Spaniards. It became known in Europe foon after the 
conqueffiof Mexico ; and thrtbeauty of the colour which 
it communicates to cl-oth very foon artradted general at¬ 
tention. For many years it was miftaken for a vegetable 
production, as had been the cafe alio with the kermes. 
Different accounts of its real nature had indeed appeared 
very early in the Philofophical Tranfadtions; but the 
opinion of Pomet, who infilled that it was the feed of a 
particular plant, gained fo much credit, that it was not 
entirely deltroyed till the publication of Mr. Ellis’s pa¬ 
per, in the fifty-fecond volume of the Philofophical Tranf- 
adtions. For figures of the cochineal infedt, the mode 
of cultivating it, and the plant on which it propagates, 
fee the article Coccus, vol. iv. p. 721, &c.* 
The quantity of cochineal difpol'ed of in Europe is very" 
great. Bancrott informs us, that the Spaniards annually 
bring to market about 6oo,oooibs. of it. Hitherto the 
rearing of the infe'dts has belonged almolt excltifively to 
that nafion. Other nations have indeed attempted to 
fhare it with them, but without any remarkable fuccefs ; 
as the Spaniards.uie every precaution to confine the true 
cochineal, and even the fpecies of cadtus on which it 
feeds, to Mexico. Mr. Thiery de Menonville Was for¬ 
tunate enough to procure fome fpecimens of both, and 
to transfer them in fafety to St. Domingo ; and feveral 
fpirited Britilh gentlemen have lately contrived to pro¬ 
cure the infedt; and vigorous efforts are making to rear 
it in the Ealt Indies. 
Cochineal readily gives out its colouring matter to 
water. The decodtion is of a crimfon colour, inclining 
to violet: it may be kept for a long time without putri- 
fying or lofing its tranfparency. Sulphuric acid gives it 
a red colour inclining to yellow, and occalions a fmall fine 
red precipitate. Tartar gives it a yellowifh red colour, 
which becomes yellow after a fmall quantity of red pow¬ 
der has fubfided. Alum brightens the colour of the de- 
codlion, and occafions a crimfon precipitate. Muriat of 
tin gives a copious fine red precipitate ; fulphat of iron, 
a brownilh violet precipitate; fulphat of zinc, a deep 
violet; acetit of lead, and fulphat of copper, violet pre¬ 
cipitates. Water is not capable of extracting the whole 
ol the colouring matter of cochineal ; but the addition of 
a little alkali, or tartar, enables the water to extradt the 
whole of it. See the article Chemistry, vol. iv. p. 345; 
and Cochineal, p. 730, of the fame volume. 
Archil is a pall^,formed of the lichen roccella, pound¬ 
ed and kept moilt for fome time with Hale urine. It gives 
out its colouring matter to water, to alcohol, and to a 
folution of ammonia in water. The tindture of archil is 
ufed for making fpirit of wine thermometers. It is a lin¬ 
gular fadl, that this tindture becomes gradually colour- 
lefs when excluded from the contact of air, and that it 
again recovers its colour when expofed to the atmo- 
fphere. The phenomenon was firlt obferved by the abbe 
Nollet, and deferibed by him in an ell'ay, publilhed among 
the Memoirs of the Academy of Sciences for 1742. The 
lichen roccella grows abundantly in the Canary Elands, 
from which it is imported and fold to the dyers. Other 
lichens are likewil'e ufed to dye red, efpeeially the parel- 
lus, from which the pigment called litmus , and by che- 
milts turnfolc, is prepared ; the oniphalodes and tartareus, 
which are often employed ip this country to dye coarl'e 
cloths. 
The rubia tinEloruui is a fmall well-known plant, cul¬ 
tivated in different parts of Europe for the lake of its 
roots, which are known by tile name of madder. They 
are about the thicknefs of a goole quill, lomewhas 
tranfparent, of a reddilh. colour, and a ftrong 1 ’mell. 
They are dried, cleaned, ground in a mill, and in that 
ftate ufed by dyers. Madder gives out its colouring 
3 mattes- 
