DIPPING. 
lime, when not too old, and too long expofed to the air, is 
the be&. It fhould. be veil fified, and freed from ftones and 
lumps. 
After two or three hours repole, the vat fhould be again 
well heey It will now exhibit figns of incipient folution ; 
inftead of black, it will appear of a dark bottle green, and 
the faeface will break into marbled veins of blue. Thefe 
appearances will increafe each time pa = is dee which 
fhould be three or four times a day 
each time the suet of the hs will aes ad mi paler, 
ke 
the marbled or veined appearance become more marked and 
ftrong, and when the fo lution is compleat, and ready for 
working, the colour, when raked up, will be a yellowith 
green. After a ‘ia of ten or twelve par to allow the 
ue, the 
n tage whatever attends 
which is now a nverflly difcarded, except by 
Of dark Blue ground, and while. 
Dark blue grounds, with fpots or figures of white, were 
amongft the firft attempts at calico-printing in the Eaft, and 
were produced, as we have before remarked, firlt, by tyin 
knots on the part intended to remain white, and afterwards 
his procefs 
O great inconveniencies, arifing from the unma- 
nageable ane of the compofition, which required keeping 
fluid by heat during the time it was applied, and could ports 
be ufed in certain plain figures, fuch as round {pots, ovals, 
&e, he defigns were of courfe rude and miler, Tittle va- 
riety being praCticable where (aes ftalks, leaves, or any 
eel more figured than a fpot or oval, could not be ob- 
taine 
. At what time the patie or referve now in general ufe was 
introduced, is not known 
ugh the rcnarin . 
ie aldol. preparing i de 
peculiar to himfelf, yet they are all effentially t de fan a 
cai Pec of one kind or another being the 3 prc 
fitance of ie pafte, which prevents the ciites of fading 
7 ee the fibres of the cloth, but from the chemical 
a of the oxyd of copper, which imparting oxygen to 
he cine. reftores it to its former blue ftate,.in which it 
poffeffes neither folubility i in pr nor Psi panies to yobd 
ida the cloth. bieae is gee of the o 
eer, The inftant the two folutions are “mixed, the indigo 
is revived, and precipitated in its original blue ftate, having 
acquired from the copper that principle of which . a ae en 
deprived by the folution of fulphate of iron. 
or referve, therefore, for dark blue grounds, mari aly 
contain oxyd of copper; we give the following lonadia as: 
moft approved of oa inu 
I. To » gallon of water add, 
of oe of copper, 
i of pipe clay. 
Boil the whole up ne a thick pafte, ftrain ape are a cloth, 
and add to it half a pint of fulphuric acid; an e pints 
of thick gum water. Mix all well together, “and {train 
again before printing, 
II or Seger of vinegar = 
an verdigrea 
of fulphate of co 
Diffolve them aly the ae and thicken wit ee ibs. of pipe- 
clay, finely gro 
he patte is act fine and {mooth, run it through the 
mill, and add to it, whilft hot, 8-ozs. ae linfeed oil, and two 
uarts of thick gum water, Strain it carefully through a 
cloth before printing. 
Ill. Tox gallon of water add, 
1 Z 
a them well in : copper pan, and, if neceffary, grind. 
hem fmooth, and add three quarts of thick gum water. 
Strain the gic very well before printin 
The firft of thefe formule contains fulphate of copper 
only, the folubility of which is increafed by the addition of 
a little fulphuric acid, which pr ea the cryttallization of 
the pafte. The fecond, which is ronger, contains alfo- 
acetate of copper; and the third, in peta to both thefe 
falts, contains a portion of nitrate of copper r formed by the 
ci e verdigreafe.. 
up the print or 
In working this, pa? the mall, or mallet, fhould be ufed 
very lightly, or not at all, if the pattern will admit of it. 
A gentle tap with the hand, fo as to leave the pafte wholly on 
the sees of the cloth, will produce the beft work. 
cloth may be dipped an hour or two aoe printing, 
if Saud, but the whites are feldom fo good as when kept: 
three or four days. The patte ‘gets hard and firm, part of 
the acid evaporates, and tne ura of copper becomes 
more intimately incorporated with the cloth. 
Derk blues, in gencral, require > from five en dips, or 
immerfions, according to we fhade of blue a or the 
firength of the vats employ 
f° the vats are aren ne orat-‘moft fix dips, will give a 
ery: 
