INDIGO. 189 
The culture of indigo is an object of considerable 
importance in the West Indian islands, and in some 
parts of America. The grounds appropriated to it 
are sown about the middle of March, in rows fifteen 
inches asunder. The plants come into flower about 
three months afterwards, and are in a state to be cut 
about the month of August. They are cut with a kind 
of reaping hook, a few inches above the root. The 
plants are then laid in strata, in a vat or cistern con- 
structed of strong mason-work, and so much water 
is poured in as will cover them. In this state they are 
left to ferment, and the fluid or pulp, which is first 
green, afterwards becomes of deep blue colour. It is 
now drawn off into another vat, where it is strongly 
and incessantly beaten and agitated, until the colour- 
ing matter is united into a body. The water is then, 
let off by cocks in the sides of the vat; and the indigo, 
after undergoing some further preparations, is cast, in 
boxes or moulds, into small pieces, each about an inch 
square, and packed up for sale. The vapour which 
issues from the fermented liquor is extremely injurious 
to the negroes who attend the process ; and as peculiar 
attention is requisite both to this and the granulating of 
the pulp, many indigo-planters have failed in the ma- 
nufacture of this article. 
Indigo is employed by dyers, calico-printers, and 
paper-stainers, to an extent so great that nearly 500,000 
pounds' weight of it are annually imported into this 
kingdom. The stone-blue used by laundresses, and the 
colours called Saxon-blue, and green, are made from 
indigo. Painters use it as a water-colour. This article 
is frequently adulterated with earth, ashes, and pound- 
ed slate. The genuine drug ought to be of rich, dark 
blue colour, approaching to black ; and, when broken, 
should display the lustre of copper. It ought not to 
sink in water, nor to leave any sediment when dis- 
solved. 
