chap, iv.] WEST INDIES. 107 
long poles;—but far more convenient machines are 
now constructed, in which the levers are worked 
by a cog-wheel, and kept in motion by a horse or 
mule. When the fluid has, by such means, been 
well churned for the space of fifteen or twenty mi¬ 
nutes, and, being tried in a cup or plate, appears 
curdled or coagulated, a strong impregnation of 
lime-water is gradually added, not only to promote 
a separation, but likewise to fix the colour and pre¬ 
serve it from putrefaction. But the planters (as 
Brown observes) “ must carefully distinguish the 
different stages of this part of the operation also, 
and attentively examine the appearance and colour 
as the work advances, for the grain passes gradu¬ 
ally from a greenish to a fine purple, which is the 
proper colour when the liquor is sufficiently work¬ 
ed; too small a degree of agitation leaving the in¬ 
digo green and coarse; while too vigorous an ac¬ 
tion brings it to be almost black.” 
The liquor being properly and sufficiently work¬ 
ed, and the pulp granulated, it is left undisturbed 
until the flakes, or jloculae, settle at the bottom, 
when the incumbent water is drawn off, and the 
indigo distributed into small linen bags to drain, 
after which it is carefully put into little square 
boxes or moulds, and suffered to dry gradually in 
the shade; and this finishes the manufacture.* 
* The following observations of Dr. Roxburgh of Bengal, con¬ 
cerning the first process, seem to have been made with great accuracy: 
« When the indigo plant is committed to cold water .in the steeping 
vat, the following appearances take place: in a few hours a slight 
