eae is neceffary to free them from the laf{t remains of 
pafte, and give a brightnefs * finifh to the whites. A 
Chien of fulphuric acid, weak enough o be borne in ane 
mouth adds inconvenience, is fafficient to diffolve. 
8 
cellence of this kind of work depends on the each and 
purity of the white, and on the fulnefs “and evennefs of the 
blue. The direGtions we have given are, with ordinary care 
and eat waaele fufficient forthe attainment of this. 
en the vats have become exhaufted by working, they 
muf be re sebed If a vat contains a tolerable charge of 
indigo, copperas, and lime, and has been are cae once, 
raking up alone will be fufficient to put it in a ftate for work- 
When again exhaufted, cosnees and lime muft 
igo. The quantity mutt 
t, and ai {uppofed quantity 
0 to 40 lbs. of cop- 
° 
i) 
fore 
2: 
oq 
: 
rakin 
IF Sail i lao of copperas and lime have been ufed 
when the vat was formed at firft, and three parts lime added 
) aa — any other addition of 
ele Some idea may be formed of the 
"by ohne its appearance 
when raked up. In general, if it looks dark green or black, 
it may be prefumed it contains a quantity of revived or un- 
diffolved indigo, and vlad and lime are therefore necef- 
eke a iene a gear rthelefs be occa- 
cele 30 
iron, othe oa a which, when Agi pais as by lime, 
is dark green; as this, how ife only through 
great onne or he ates - is not phen likely to be the 
cafe, as the quantity of copperas required to produce this 
effe& oa be very great in 
navat rakes up ene or very pale bch ie 
it Is faapet: y fome ‘to contain too much co 
mutt be corrected by the addition of more lime. 
ee. as we have before obferved, to fay a vat contains an 
excefs of copperas, fince this falt cannot exift in folution 
j A want lime, and in this cafe it will 
be very weak, of a pale yellowith ae produce a very feeble 
blue, and the pafte will invariably creep, to ule the dyers’ 
phrafe, or in other words, will rua, aad lofe the tharpnefs 
pace of = impreffion, the cinerea : is entered in t 
vat. This may be the cafe at thet e vat contains : 
quantity of ele indigo alfo, and as up black, fo that 
no certain co ema can be drawn from the yellowith ap- 
pearance afor 
If a vat ce wreak, the froth which forms at the top during 
raking, is pale fy blue ; the furface does not lamer break 
arble veins, nor is it foon covered with a blue 
rN trong well conditioned vat, on the contrary, when raked 
up, becomes aeine dire&tly with a permanent . a 
froth, the colour of which varies from a deep blue, when 
the vat is of odie ftrength, to a baal Bee ane 
which is always characteriftic of a very ftrong folution, and 
the furface, when {ki 
thick fi 
cop 
digo, — is called - Eker’ of the eid by the old d 
In fkimming, ¢ be taken tee is carefully 
ieee: and ad aa into the an at the time they 
are refrethed 
When a ‘eit becomes fo exhaufted that further additions of 
lime and copperas have no cffe& in increafing the ftre ngthy. 
frefh acne muit be added, with the proportions of lime and 
eral — unworked and without ° 
raking, it will abfo a Gace ough from the air to pres 
cipitate the indigo from the Pua fo that, to the depth 
of ro or 12 inches from the furface, it will confit of lime-~ 
When the dregs have accumulated fo much as to prevent 
the vat from clearing in 24, or at om 36 hours, and when 
the frame begins to touch'the m 
the 
opperas, fo as to get out all the aes ie the 
t dregs are thrown away as exhautted 
Of Pale Blue.. 
Pale blues are, in Lg safes at a fingle dip; they 
require lets. indigo and labour than the pre ceding ftyle of 
work, but more care and management to do them well.. 
They are liable to be uneven and {potted in ane ground, and’ 
the proper tone and fhade of colour is a matter of great im- 
portance, and alfo of no {mall difficulty 
a fhall ape firft of pale biues meh white, intended to 
nifhed up with cia ser or not.—The pafte for eee 
bor Gee Wee me : 
ve 
already given, w 
ood u ~~ other folution of copper 
ill t be equally. efficacious, but the fulphate,.as being the: 
cheapeft, may be confidered as the bett.. ° 
The preparation, or rather the condition of the cloth, is. 
a matter of the greateft importance in pale blue dipping.. 
If imperfeQly bleached, or ftained or impregnated with any: 
earthy or metallic fubfance that will obfiru€t. the entrance. 
. the dye, the blue will infallibly be uneven. A diffe 
n the clhre! of [ e hairy in the finenefs of the weft, or 
in the hardnefs o ich the cloth is made, 
will per con edeetien aos in the fhade a 
defeat every att n the part of 
jaftice to his work, To guard as much as poffible againft 
this, the cloth, in the "gl place, fhould be feleéted pur= 
pofely, rejeGting all thofe pieces which thew unevenmels in: 
eae or variation in the quality of the materials 
s fhould be in the beft poflible ftate fr aa 
e eee 
take a ftiff calendering.. 
venient, they fhould be removed from the warm fhop.to a 
cool fituation, where they will not.get parched and dry, andi 
dipped at furtheit the following day. 
ll thefe precautions, however, are inadequate to fecure 
an even and level ground, without fecouile to the improved: 
