essel that contains it. To
allay this violent fermentation, oil is thrown in as the froth rises,
which instantly sinks it. When this beating has continued for twenty,
thirty, or thirty-five minutes, according to the state of the weather
(for in cool weather it requires the longest continued beating), a
small muddy grain begins to be formed; the salts and other particles
of the plant united, dissolved, and before mixed with the water, are
now re-united together, and begin to granulate. To discover these
particles the better, and to find when the liquor is sufficiently
beaten, they take up some of it from time to time on a plate, or in a
glass; when it appears in a hopeful condition, they let loose some
lime water from an adjacent vessel, gently stirring the whole, which
wonderfully facilitates the operation; the indigo granulates more
fully, the liquor assumes a purplish color, and the whole is troubled
and muddy; it is now suffered to settle; then the clearer part is
permitted to run off into another succession of vessels, from whence
the water is conveyed away as fast as it clears on the top, until
nothing remains but a thick mud, which is put into bags of coarse
linen. These are hung up and left for some time until the moisture is
entirely drained off.

"To finish the drying, this mud is turned out of the bags, and worked
upon boards of some porous timber, with a wooden spatula; it is
frequently exposed to the morning and evening sun, but for a short
time only; and then it is put into boxes or frames, which is called
the curing, exposed again to the sun in the same cautious manner,
until, with great labor and attention the operation is finished, and
the valuable drug fitted for the market. The greatest skill and care
is required in every part of the process, or there may be great danger
of ruining the whole; the water must not be suffered to remain too
short or too long a time, either in the steeper or beater; the beating
itself must be nicely managed, so as not to exceed or fall short; and
in the curing the exact medium between too much or too little drying
is not easily attained. Nothing but experience can make the overseers
skilful in these matters. There are two methods of trying the goodness
of indigo; by fire and by water. If it swims it is good, if it sinks
it is inferior, the heavier the worse; so if it wholly dissolves in
water it is good. Another way of proving it, is by the fire ordeal; if
it entirely burn