Indigo.

American Farmer, 10.9.1828.

On the method of Manufacturing Indigo on the coast of Coromandel, in India, and Senegal, under the auspices of the French government, by George M. Gibbes, of Combahee, S. C. - addressed to William Washington, Esq, and by him politely handed to us for publication.

Combahee, Dec. 3, 1827.

* See Bancroft on Permanent Dyes, and Mungo Park's Mission to Africa, page 143, for another mode practised in that country.Sir, - The importance of multiplying the staple productions of the Southern states, induces me to suggest to the consideration of the Agricultural Society of South Carolina, the expediency of encouraging experiments in the cultivation of indigo; and particularly of manufacturing it from the dry leaves, as practised on the coast of Coromandel, in India; and recently, in Senegal, under the immediate auspices of the French government - instead of from the green weed, as was formerly done in this state. According to information obtained from a highly respectable proprietor, and extensive practical manufacturer, during a period of fourteen years in the former country, (and now resident in this,) almost the whole of the indigo made in Coromandel, is manufactured from the leaves of the plant only, after they have been dried, packed, and transported to the factories by the farmers, and, in most instances, from distant parts of the country. After the plant is cut, it is spread out to dry in the sun, on a space of ground left for the purpose, for about six or eight hours, when it is threshed or shaken in the hand to break off the leaves, which crumble easily: the stems are then raked off as useless, the impression being, from various experiments, that this part of the plant contains little or none of the colouring matter, and the leaves are packed away in the house, as tight as possible, so as to preserve them from the air, until the harvest is completed and the farmer is at leisure either to manufacture himself, or to transport them to the regular factories. If the season is wet, drying the house is resorted to; and when the leaves crumble in the hand, it is considered indication of their being sufficiently cured. The advantages of thus separating the two operations of harvest and manufacture (which otherwise go together, from the necessity of steeping the green plants as soon as cut), the saving of transportation of the heaviest portion of the plant from the field to the vats, as well as the postponement of the manufacturing process, until the healthy season, when the superintendence of the proprietor may be obtained, will be at once apparent to the practical agriculturist. And if the cultivation only could be confined to the plantation, and the manufacture performed at regular factories where the business could be conducted on a larger scale, there is little doubt but that (as in almost all other operations of the kind) superiority in the quality of the article made and economy in the use of the raw material, would be the consequence. The great objections of our old planters to the pursuit viz: the uncertainty or the result, and disagreeableness, if not unhealthfulness of the fermenting process would be removed, and the simplicity of the whole business promoted. When a view to this end, a distinguished professional [-] of New York, Mr. William Partridge, has offered to receive, to the amount of several tons, [-] the next season, and cured according to the foregoing directions; and will return to the [-] two-thirds of any profits which may result from the experiments made. This gentleman has obtained a Patent for dyeing from the leaf, either dried, or, in its fermented state, according to the African mode of preparing it, which is by simply moistening and grinding the dry leaves sufficiently to produce fermentation and adhesion, so as to permit of its being rolled into balls, and packed for market;* and which is the same process generally pursued in preparing woad in England, and in which state the woad imported into this country is received. As it is believed that no experiments in preparing indigo for market by this latter mode have been made public, it is presumed to be equally entitled to trial as any other, especially when it is considered that the African blue dyes are superior to those obtained from the best Madras indigo.

The great superiority in the quality of indigo now made, over that which was formerly produced either in India or America, its enhancement in value, and the constantly increasing demand, would seem sufficiently important considerations to induce a partial return to its cultivation, in the present depressed state of the cotton market, independent of the benefit which may be expected to the land itself by a change of crop. It is true, that considerable doubt has been entertained whether the superiority of the indigo now made, is owing to greater skill, or to the more favourable soil and climate of India.

There are two circumstances which appear calculated to promote a belief, that the former is the chief, if not the only cause; viz. that previous to 1779, the year in which the East India Company commenced making indigo in India, the article there was inferior to that made in the United States, from whence Great Britain received her principal supplies; and also, that of what is now made in Carolina, a portion is of the very first quality, as admitted by the dyers in the Northern states, who are in the habit of using, annually, the small quantity which is still produced in our upper districts.

The difficulty of obtaining accurate information as to the most improved modes of preparing indigo, now practised in other parts of the world, renders it impossible to institute a comparison with that which was customary in Carolina, before it was abandoned as a staple, from which the extent of those improvements may be estimated. But it is reasonable to conclude, that under the patronage of the British government, and with the aid of chemistry, they must have been considerable. As far as I have been able to learn from the various sources consulted, they consist chiefly in the period of cutting the plant, as a subject of the very first importance; and next, in the steeping and beating process - size of the vats, &c. It is universally admitted, however, that perfection in the art of indigo making, is more a matter of experience than of science, and that no particular rules will prevail at all times, even in the same country; that nothing, indeed, short of long practice and minute attention, can possibly lead to successful results.

As regards the proper time of cutting the plant, there is much variety of opinion. In Coromandel, it is not considered lit to cut, until the plant is in full blossom, and just before seeding; whilst, in India, generally, (as stated in Loudon's Encyclopaedia of Agriculture,) the plants are not allowed to come to flower, as the leaf in that case becomes dry and hard, and the indigo produced is of less value." - The improvement lately introduced into France by M. Morina, an Italian, in obtaining indigo from the woad plant, by cutting the leaves when very green, instead of when ripe, as formerly, may, perhaps, add more strength to the latter opinion, from the similarity of the two plants. In a memoir on indigo, lately received from a cultivator in the neighbourhood of Caraccas, it is observed, that "the weed is cut about three and a half months after planting; and the most certain method of knowing the period of its maturity, is, by squeezing the young shoots in the hand; if it cakes, it is not ripe; but if it pulverizes, it is then fit to cut."

When the green weed is to be steeped, from the necessity of doing so the same day on which it is cut, it is evidently impossible to harvest the whole crop at the precise period of its perfection, as this operation must be dependent on the progress of the manufacture; which circumstance, with the difficulty of obtaining skill in the manufacture, as well as the scarcity of clear and soft water in the low country, which is so indispensable in making good indigo, afford additional reasons for confining the planter to its cultivation only, should the plan proposed be found practicable.

The improvements which are stated to have taken place in the large factories in India, are chiefly in the attention to cleanliness, by which all extraneous matter is excluded, and the expedition with which the beating process is performed, by means of machinery, and on which the quality of the indigo is said so much to depend: for, in the process of oxigizing, by which it is converted from the green to the blue state, the rapidity with which it is exposed to the atmosphere, is considered by chemists as allimportant to the perfect separation which should take place of the colouring matter from the salts and extraneous liquor: and to the slow mode of doing which, as formerly practised in Carolina, as well as to the too great quantities or lime used to facilitate the precipitation or the feculæ, has been, in a great measure, ascribed to the inferiority of the article made. In India, lime-water only is used, and that sparingly; and, in testing the perfection of this stage, it is observed that the most certain indication, next to that of the apparent separation of the dregs, is the colour of the water, which should be that or brandy; and if either green or black, that there has been a defect, and the indigo will not be good. If my information is correct, that it was customary, formerly, in this country, to continue the beating after the precipitation was observed to have taken place, it may be considered as another great defect, as it is now well understood, that in this event a reversion of the particles, and consequent formation ensues, which completely spoils the colour.

Similar expedition is attended to in the previous steeping of the weed, as twenty minutes only is pre scribed as proper to be allowed for filling the vats. It is in this branch or the business, that the greatest advantage results from the use or the dry leaves; for, in steeping them, only one or two hours is requisite to extract the colouring matter, and no fermentation takes place: whereas, in fermenting the green weed, twelve hours or more is required. Be sides which, there is always some uncertainty in the success of the latter process - for, if the fermentation is too great, the quantity is increased, but the quality certainly injured.

The dimensions of the vats (which can be furnished, if desired,) are proportioned to each other, and greater success is found to exist, when the business is conducted on a large, than on a small scale.

In the cultivation of the plant, there does not appear any material difference in the different countries where it grows, other than such as local circumstances render necessary - and the probability is, that the mode best suited to our soil is that which was practised.

In the State of Salvador, (the crop of which, for the year 1825, was valued at $2,400,000,) a rich, moist soil is required - the seed is sown three or four inches deep, and the plant flowers in two months. In Coromandel, a cool soil is preferred, by which is meant, that where water is found at a short distance below the surface; and the height which the plant attains, is a strong indication or the quantity or colouring matter to be expected - it being observed, that four feet was the best height, and that when it reached eight feet, the quantity and quality of indigo made were both deficient. The quantity of indigo made to the acre is not easily ascertained. In the West Indies, where it is cut three or four times, the yield has been as high as five hundred pounds - and, in some of the interior provinces of Hindostan, when they have as many as nine cuttings, it is said to be still greater.

When it is considered that the estimated value of the indigo annually consumed in the United States, is upwards of §4,000,000, and that the in creasing demand is likely to keep pace with the in crease of manufactures generally; that a protecting duty of fifteen cents a pound already exists, and that complete security from foreign competition must ensue, should the contemplated commercial policy of the country go into effect, the expectation may not be chimerical, that this valuable plant, which is indigenous to the soil of Carolina, will once more become a source of wealth and prosperity to the state.

With great respect, I am, sir,
Your obed't serv't,

GEORGE M. GIBBES.

P. S. - I send you a few roots of the madder, which, as well as the wild plant, and the Sicily sumach, are articles of increasing consumption in the manufactories of the north, and may be well worth trial in this climate. Several very profitable experiments have been made with them recently at the north; and the wild sumach has been cultivated to some extent, although the quality in that climate is so inferior as to command only one half the price of that which is imported from the more mild regions of Portugal and Sicily.