 | The South-west |  |
Note F.—Page 241.
To the politeness of Dr. William Dunbar, a planter of Mississippi,
the author is indebted for many important papers relating to
this region, formerly in the possession of his father—a gentleman
well known to the philosophic world as the author of several valuable
scientific papers upon the natural history and meteorology
of this country. Among the manuscripts of this gentleman in the
author's possession, is the following account of the manufacture
of Indigo, written by himself, then an extensive indigo planter,
near New-Orleans.
“The reservoir water in or near the field where the indigo plant
is cultivated, is prepared, in lower Louisiana, by digging a canal from
eighty to one hundred feet long, and 25 or 30 feet wide. The plant
is in its strength when in full blossom: it is then cut down, and
disposed regularly in a wooden or brick vault, about ten feet square,
and three feet deep; water is then poured or pumped over it until
the plant is covered; it is suffered to remain until it has undergone
a fermentation, analogous to the vinous fermentation. If it
stands too long, a second fermentation commences, bearing affinity
to the acetous fermentation: your liquor is then spoiled, and
will yield you but little matter of a bad quality—sometimes none
at all. The great difficulty is to know this proper point of fermentation,
which cannot sometimes be ascertained to any degree
of certainty; when the plant is rich, and the weather warm, a tolerable
judgment may be formed by the ascent or swelling of the
liquor in the vat; at other times no alteration is observed. But
to return; the liquor is at length drawn off into another vat, called
the beater; it may remain in the first vat, called the steeper, from
ten to fifteen hours, and even twenty-four hours, in the cool weather
of autumn. The liquor is agitated in the beater in a manner
similar to the churning of butter; when first drawn off, it is of a
pale straw colour, but gradually turns to a pale green, from thence
to a deeper green, and at length to a deep blue. This is occasioned
by the grains of indigo, at first dissolved in the water, and
afterward extricated by beating. The indigo is now ready to fall
to the bottom by its superior specific gravity; but a precipitant is
often used to cause a more hasty decomposition, and consequent
precipitation. This is effected most powerfully by lime-water,
but it may also be done by any mucillaginous substance, as the
many others indigenous in this country. The saliva produces the
same effects. A few hours after the precipitation, the water standing
above the indigo is drawn off by holes perforated for that purpose;
the indigo matter is then swept out and farther drained,
either by putting it in bags of Russia duck, or more commodiously
in wooden cases with a bottom of cloth; after which it is put in a
wooden frame, with a loose Osnaburg cloth between it and the
frame, and subjected to a considerable press—light at first, but
heavy at the last; and when solid enough, cut into squares, which
shrink up in drying to half their first bulk. After it appears to be
dry, it is put up in heaps to sweat and dry the second time; it is
then fit for market. All that has not been injured by missing the
true point of fermentation, sells here generally at a dollar a pound.
The planter often, by mistake, makes his indigo of a superior
quality, so as to be equal to the Guatimala indigo, and be worth
from one dollar and a quarter to two dollars. This happens from
the indigo maker's drawing off his water from the steeper too
soon, before it has arrived at its due point of fermentation. In
this case the quantity is so much lessened, as by no means to render
the planter compensated by the superior quality. The grand
desideratum to bring the making of indigo to some degree of
certainty, is the discovery of some chymical test, that shall demonstrate
the passing of the liquor from the first to the second fermentation.
This test will probably be discovered in some saline
body, but which, or in what quantity, it is yet difficult to ascertain.”
| The South-west | |