306 
MANUFACTURING INDIGO. 
For the American Agriculturist. 
MANUFACTURING INDIGO. 
About the year 1797, I bought in London two 
chests of indigo, said by the seller to have been 
manufactured by the late General Wade Hamp¬ 
ton of South Carolina. It was a brilliant, copper- 
colored indigo, and proved in consumption equal 
to any Bengal I ever used. Some twenty years 
since I opened a correspondence with General 
Hampton on the subject of manufacturing indigo 
in this country, when he informed me “ that rais¬ 
ing cotton paid the planter much better than culti¬ 
vating the indigo plant; that the manufacture was 
injurious to the health of the workmen; and that 
the art of manufacturing it was lost in this coun¬ 
try, at least in the most essential particulars, for 
want of a continuous practice.” 
In the year 1828 I corresponded with Elias Hor¬ 
ry, Esq., then chairman of the Charleston Agri¬ 
cultural Society, on the subject of indigo and mad¬ 
der. The following is an extract from Mr. Hor¬ 
ry’s letter in answer : “ Our Agricultural Society 
will consider itself much obliged by the important 
and scientific information which you have commu¬ 
nicated, respecting those valuable dye-stuffs. I 
have placed your letter into the hands of the Editor 
of the Southern Agriculturist, in order that the in¬ 
formation it affords respecting indigo and madder 
may be known as soon as possible.” 
In the month of March, 1830, I sent an article 
to B. Silliman, Esq., Editor of the Journal of Sci¬ 
ence, more extended than the former, which was 
published in the number for May of that year. 
In the years 1828 and 1830, cotton afforded to 
the planter so large a profit, that no attention was 
then paid to the cultivation of minor articles; but 
so little profit is now derived from this cultivation, 
that madder, sumach, and indigo, particularly the 
two last, as being annual crops, will be far more 
lucrative. I am induced, therefore, to send you a 
copy of what I have formerly written on indigo, 
that it may be again brought to the notice of our 
southern agriculturists. 
The value of the indigo consumed in this coun¬ 
try in 1829, can not be estimated at less than two 
millions of dollars. Of the quantity consumed, 
there was made in the United States about two 
hundred thousand pounds, or one tenth part of the 
consumption. As the consumption is rapidly in¬ 
creasing, from the increase of population from the 
extension of manufactures already established, and 
from the introduction of new articles of manufac¬ 
ture, I consider it an object of national importance, 
that it should be better made, and more extensive¬ 
ly cultivated in this country. 
I have been acquainted with the indigo market 
for more than thirty years, and never remember it 
in so depressed a state as it has been for the last 
twelve months. The average price of the sales 
for the last year can not have been much over one 
dollar per pound. The average price of the im¬ 
ported has been about one dollar and fifteen cents, 
and of that made in this country, about fifty cents. 
To endeavor to give such instruction to the plant¬ 
ers as will enable them to make an article fully 
equal to the imported, is the object of this com¬ 
munication. 
The quantity of indigo made from an acre of the 
plant has been differently estimated by almost 
every maker from whom I have obtained informa¬ 
tion. General Wade Hampton, who many years 
since made the article in South Carolina, informed 
me, that he obtained sixteen pounds of fine indigo 
from the plant taken from a half acre, or thirty- 
two pounds per acre. Other estimates make the 
quantity much larger, some nearly two hundred 
pounds to the acre. Taking the average of the 
different estimates, it would be at least fifty pounds. 
It will appear by this estimate, that it would re 
quire forty thousand acres of land to raise a sup¬ 
ply for the present consumption; and as the de¬ 
mand is rapidly increasing, it is more than proba¬ 
ble, that in ten years, it will require the product 
of eighty thousand acres to raise a supply for home 
consumption. 
There are four points to be attended to in the 
making of indigo, which require much judgment, 
aided by practical skill. These are, the time of 
cutting the plant, the degree of fermentation to be 
given in the steeper, the degree of oxydizement 
of the coloring fecuke, and the extrication of for¬ 
eign matter from the pulp after the indigo is made. 
Three of these processes being purely chemical, 
it is not, therefore, surprising that ordinary work¬ 
men should frequently fail in producing a good 
article. There is probably more loss sustained by 
our planters from the ignorance of the operators, 
than the whole value of the article now sold. 
The plant should be cut when at maturity, as 
it will then afford a fine color; but if cut too late, 
a portion of the color is then lost, and an indigo of 
worse quality is obtained. Mr. Dalrymple inform¬ 
ed me, that the plant should be cut when in full 
flower, after the weather for some days has been 
dry. Another celebrated maker of indigo, asserts 
that if the plants are suffered to stand till they run 
into flower, the leaves become too dry and hard, 
and the indigo obtained from them proves less in 
quantity and less beautiful; the due point of ma¬ 
turity is known by the leaves beginning to grow 
less supple, or more brittle. 
It appears that the makers of indigo differ as to 
the time of gathering the plant. It is greatly to 
the interest of our planter that they should ascer¬ 
tain, by direct experiment, the proper time of 
gathering the plant. 
When the plant is gathered, it has to undergo 
a process by immersion in water, for the purpose* 
of extracting its coloring matter. This operation 
is performed in two ways—by fermenting the 
green plant in a steeper, or by first drying the 
leaves and then simmering them in a boiler. The 
latter process is now pursued by some of the best 
makers in Bengal, and has apparently an advan¬ 
tage over the old process. 
When the green plant is fermented in a steeper, 
and the process is carried a little too far, the col¬ 
oring matter will become dark, and is said to be 
burnt—if carried a slight degree farther it will be 
black, and of course the indigo will be very much 
injured. Nine tenths of the indigo made in the 
United States partakes more or less of this char¬ 
acter, and has evidently been injured by an exces¬ 
sive fermentation. To observe a due degree of 
