438 On Indigo. 
The liquid is now transferred into a tall cy- 
lindric jar, of about | inch internal diame- 
ter; more water is poured in till the mixture 
becomes sufficiently dilute to shew the figure 
of the flame of a candle through it Tben 
the liquid oxymuriate is mixed with the li 
quid gradually and by measure, agitating 
duly each time, and never putting any more 
in till the smell of the preceding has vanished, 
The liquid soon becomes transparent and of 
a beautiful greenish-yellow appearance: after 
the dross has subsided, the clear liquid may 
be poured off, and a little more water put to 
the sediment, with afew drops of oxymuriate 
of lime, and a drop of dilute sulphuric acid; 
if more yellow liquid is produced, it arises 
from particles of indigo which have escaped 
the action of the oxymuriate before, and 
must be added to the rest. 
The value of the indigo I consider in pro- 
portion to the quantity of real oxymuriate of 
lime necessary to destroy its colour. The 
value also may be well estimated by the quan- 
tity and intensity of the amber-coloured hi- 
quid which the indigo produces, and this is 
found independently of any valuation of the 
oxymuriate of lime. 
