The Commercial Products of the Vegetable Kingdom / Considered in Their Various Uses to Man and in Their Relation to the Arts and Manufactures; Forming a Practical Treatise & Handbook of Reference for the Colonist, Manufacturer, Merchant, and Consumer, on the Cultivation, Preparation for Shipment, and Commercial Value, &c. of the Various Substances Obtained From Trees and Plants, Entering into the Husbandry of Tropical and Sub-tropical Regions, &c.

by P. L. Simmonds

"The time of planting the indigo is generally after the first rains succeeding the vernal equinox; the seed is sown in small straight trenches, about eighteen or twenty inches asunder; when it is at its height, it is generally eighteen inches tall. It is fit for cutting, if all things answer well, in the beginning of July.

"Towards the end of August a second cutting is obtained, and if they have a mild autumn, there is a third cutting at Michaelmas. The indigo land must be weeded every day, the plants cleansed from worms, and the plantation attended with the greatest care and diligence. About twenty-five hands may manage a plantation of fifty acres, and complete the manufacture of the drug, besides providing their own necessary subsistence and that of the planter's family.

"Each acre yields, if the land be very good, 60 or 70 lbs. weight of indigo, at a medium the produce is 50 lbs. This however, is reckoned by many skilful planters but a very indifferent crop.

"When the plant is beginning to blossom it is fit for cutting, and when cut great care ought to be taken to bring it to the steeper without pressing or shaking it, as great part of the beauty of the indigo depends upon the fine farina, which adheres to the leaves of this plant. The apparatus for making indigo is inconsiderable and not expensive, for besides a pump, the whole consists only of vats and tubs of cypress wood, common and cheap in this country.

"The indigo, when cut, is first laid in a vat, about twelve or fourteen feet long and four feet deep, to the height of about fourteen inches, to macerate and digest; then this vessel, which is called the steeper, is filled with water; the whole having laid from about twelve to sixteen hours, according to the weather, begins to ferment, swell, rise, and grow sensibly warm. At this time spars of wood are run across, to mark the highest point of its ascent; when it falls below this mark, they judge that the fermentation has attained its due pitch, and begins to abate; this directs the manager to open a cock, and let off the water into another vat, which is called the beater; the gross matter that remains in the first vat is carried off to manure the ground, for which purpose it is excellent, and new cuttings are put in, as long as the harvest of the weed continues. When the water, strongly impregnated with the particles of indigo, has run into the second vat or beater, they attend with a sort of bottomless buckets, with long handles, to work and agitate it, when it froths, ferments, and rises above the rim of the vessel 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 burns away it is good, the adulterations remain untouched."

Indigo to the extent of 220,000 lbs. per annum is grown in Egypt. The leaves are there thrown into earthen vessels, which are buried in pits and filled with water; heat is applied, and the liquid is boiled away until the indigo becomes of a fit consistence, when it is pressed into shape and dried. Many Armenians have been invited from the East Indies to teach the fellahs the best mode of preparation, and, in consequence, nine indigo works have been established belonging to the government.

The indigo plant is found scattered like a weed abundantly over the face of the country in the district of Natal, Eastern Africa. It is said that there are no less than ten varieties of the plant commonly to be met with there. Mr. Blaine submitted, in 1848, to the Manchester Chamber of Commerce, a small specimen of this dye-stuff, which had been extracted by a rude process from a native plant, which was pronounced by good authority to be of superior quality, and worth 3s. 4d. per pound. Mr. W. Wilson, a settler at Natal, in a letter to the editor of the Natal Witness, thus speaks of the culture:—

"My attention was first forcibly drawn to the cultivation of indigo by some seed imported by Mr. Kinlock, from India. This seed, on trial, I found to grow luxuriantly; and after a few experiments I succeeded in manufacturing the dye. The success which thus attended my first attempts has encouraged me to try indigo planting on a more extensive scale. For this purpose I am allowing all the plants of this season to run to seed, and intend to plant equal quantities of Bengal and native indigo.

While my attention was engaged in these preliminary experiments, I observed that the country abounded in a variety of species of indigo, and by a series of experiments found it rich and abundant, and have since learnt that it is known and in use among the natives, and called by them Umpekumbeto.