DYING. 
155 
a browning, and foretimes logwood is added : thefe co¬ 
lours are l'ometimes made to incline towards purple and 
erimfon, by dying them in the remains of a cochineal 
bath, or by putting a little madder or cochineal into the 
bath ; by a little tartar the colour is rendered lighter. 
For hazel colours, galls, fultic, and logwood mull be 
mixed, and more or lefs madder, with a little alum, are 
to be put in. 
To produce a violet colour, Mr. Guhliche alums a 
pound of woollen duff in a folution of two ounces of 
alum; he makes a bath with, an ounce of cochineal, and 
adds an equal quantity of folution of iron, in which he 
keeps the fluff until it has acquired a proper fhade. Li¬ 
lacs may be dyed with the remainder. If a colour with 
lefs of a brown call be required, a fmall quantity of folu¬ 
tion of iron is employed, and an ounce of nitre mud be 
introduced. Brazil-wood, the colour of which has been 
extrafted by means of the aceto-citric or nitro-muriatic 
acid, may alfo be employed in the fame manner. 
A puce colour may be obtained from madder, giving a 
pound of woollen duff a boiling in a mixture compofed 
of two ounces of alum, a certain quantity of vinegar, 
and folution of iron. After a quarter of an hour’s ebul¬ 
lition, it is left twelve hours in the mordant. A bath is 
made with the deception of two ounces pf white galls 
poured off clear from the fediment, in which four ounces 
of good madder are'mixed ; and when it begins to grow 
hot, the dud’ is dipped when taken out of the mordant, 
and fud’ered to remain there, gradually increafing the 
heat, until it has taken the defired colour ; It is then 
boiled for two minutes, walked and dried in the fun. 
The colour obtained by this procefs is very durable. If 
the alum and vinegar of the mordant be omitted, a deeper 
brown is produced : f after thefe colours the lighter (hades 
are dyed. It is alfo found, that brazil and logwood em¬ 
ployed in equal quantities, or in other proportions, give 
different brown colours of tolerable durability, when 
more or lefs folution of iron is mixed with a decottion of 
them, and the wool previoudy alumed and galled, is 
dyed in it; thefe colours have not, however, the dura¬ 
bility of the former. Various (hades of mor-dore and 
capucine may be given to the above colours, by dipping 
them, as foon as taken out of the dye, in a bath compofed 
of annotta. 
Of DYING SILK. 
The fibres of filk are naturally covered with a kind of 
varnifh, or gummy fubftance; and almoft the whole of 
what we know in Europe is tinged of a yellow colour, 
which it is neceffary to remove, as well as the vamifh, 
for mod of the purpofes to which filk ps applied. This 
is commonly done by fubmitting it to the aftion of foap, 
in circumftances which are already fufficiently known. 
When filk has been freed from both its gummy varnifh 
and its yellow colour, it is fometimes neceffary to whiten 
it dill farther, by the fumes of fulphur applied to it, and 
confined in a dove. But though fulphureous acid gas, 
applied in this way, readily whitens the filk, and thereby 
renders it more fit to exhibit lively colours, a portion of 
fulphur adheres to it, which mud be removed by foaking 
and agitation, for a conliderable time, in warm water, 
that it may not tarnifh the colours intended to be given 
by dying; an effett which fulphur generally produces, 
both to thofe of wool and filk. The ludre fo much de¬ 
fired in colours dyed upon filk, feems, in a great degree, 
to refuIt from the glofs and polidt of its furface, which 
acids, alkalies, and other chemical agents (particularly 
the folutions or oxyds of tin), contribute to impair, and 
are therefore to be fparingly ufed. Silk, in its difpofition 
to receive and retain colours for dying, feems to partake 
of a middle nature between that of the animal and vege¬ 
table fubdances: by its abundance of azot and hydro¬ 
gen, it polfeffes, like wool, a drong attraction for colour¬ 
ing matters; but its fibres having neither a fimilar orga¬ 
nization, nor an equal degree of elafticity, it is capable 
of imbibing colour?, like linen and cotton, without any 
previous dilatation of its pores by hot water, but, like 
them, it parts with the colours fo imbibed the more eafily, 
-in confequence of this natural opennefs, or the want of 
contraction, in its pores; though, upon the whole, co¬ 
lours dyed in filk are more lading than when dyed in linen 
and cotton, on account of its greater affinity with colour¬ 
ing matters, refulting from its animal nature. 
Blue Silks are ufually dyed by the following procefs : 
Six parts of bran, and fix of indigo, with nearly one pars 
of madder, are dirred into a fufficient quantity of water, 
in which fix parts of common potalh of commerce is dif- 
folved. The liquid is kept at a temperature proper for 
fermentation. When the indigo, deprived of its oxygen 
by the fermentation, is diffolved by the potafli, the liquid 
alfumesa green colour. The filk, previoudy well fcoured, 
is put into the folution in fmall quantities at a time; 
then wrung out of the dye, and hung up in the open air, 
till the green colour which it has at fil'd is changed into 
blue. Some dyers ufe the vats when grown weak to dye 
lighter (hades : but the blue obtained in that cafe is lefs 
beautiful, and lefs permanent, than when fredi vats con¬ 
taining a fmaller quantity of indigo are made ufe of: but 
indigo alone is incapable of giving filk a deep blue : there¬ 
fore, when this is required, it is neceffary to prepare it 
by previoudy giving it a ground colour. For the Turkey 
blue, which is the deeped, a very drong archil bath is firft 
prepared ; and for the royal blue one of the fame kind, 
but weaker. All light blues are dyed without any 
ground being previoudy given. There is, however, a 
blue made as de p p as the royal blue, for the ground of 
which cochineal is ufed indead of archil, in order to ren¬ 
der it more permanent, whence the title bleu fin has been 
given it: a blue of little durability may be given to (ilie 
by means of verdegris and logwood ; but it might be 
made more lading, by fird giving it a lighter (hade than 
is intended in a bath of this kind, afterwards dipping it 
in an archil bath, and in the vat after that. 
Yellow Silks, of many did'erent (hades, are dyed 
either by weld, or quercitron bark, but the lad is the 
cheaped of the two. The proportion diould be from one 
to two parts of bark to twelve parts of filk, according 
to the (hade. The bark, tied up in a bag, ffiould be put 
into the dying veffel while the water which it contains 
is cold, and when it has acquired the heat of about one 
hundred degrees, the filk, previoudy alumed, (hould be 
dipped in, and continued till it affumes the wifhed-for 
colour. When the (hade required is deep, a little chalk 
or pearl-afh diould be added towards the end of the ope¬ 
ration. When a very lively yellow is wanted, a little 
murio-fulphat of tin (hould be added, but not too much, 
becaule tin always injures the gloffinefs of filk. The 
proportions may be four parts of bark, three of alum, 
and two of murio-fulphat of tin. Silk is dyed fine 
orange, jonquille, and aurora, colours by annotta. The 
procefs is merely dipping the (ilk into an alkaline folu¬ 
tion of annotta. To produce the orange (hade, the alkali 
is faturated with lemon juice. The colours thus pro¬ 
duced are exceedingly beautiful, but they are apt to want 
permanency. 
A very bright, (tuning, and durable yellow dye, very 
convenient for filk, has been lately extradited from yellow 
muflirooms. Thefe are pretty large, and grow commonly 
under walnut and apple-trees. Its colouring matter is 
contained in abundance, not only in the tubular part, but 
alfo in the parenchyma of the body of the mufnroom. 
In order to extract it, the muffiroom is pounded in a 
mortar, and the liquor thence obtained is boiled fora 
quarter of an hour in water. An ounce of liquor is fuf¬ 
ficient to communicate colouring-matter to fix pounds of 
water. When the liquor has been (trained, the (tuff to 
be dyed is put into it, and boiled for a quarter of an hour. 
All kinds of (tuff receive this colour and retain it, but on 
linen and cotton it is lefs bright. This colour may be 
modified, in a very agreeable manner by the effect of 
mordants. 
