The districts of Kishnagar, Jessore, and Moorshedabad, in Bengal, ranging from 88 to 90 degs. E. lat.i.tude, and 22 to 24 degs. N.

longitude, produce the finest indigo. That from the districts about Burdwan and Benares is of a coa.r.s.er or harsher grain. Tirhoot, in lat.i.tude 26 degs., yields a tolerably good article. The portion of Bengal most propitious to the cultivation of indigo, lies between the river Hooghly and the main stream of the Ganges.

In the East Indies, after having ploughed the ground in October, November, and the beginning of December, they sow the seed in the last half of March and the beginning of April, while the soil, being neither too hot nor too dry, is most propitious to its germination. A light mould answers best; and sunshine, with occasional light showers, are most favorable to its growth. Twelve pounds of seed are sufficient for sowing an acre of land. The plants grow rapidly, and will bear to be cut for the first time at the beginning of July; nay, in some districts so early as the middle of June. The indications of maturity are the bursting forth of the flower buds, and the expansion of the blossoms; at which period the plant abounds most in the dyeing principle. Another indication is taken from the leaves, which, if they break across when doubled flat, denote a state of maturity. But this character is somewhat fallacious, and depends upon the poverty or richness of the soil. When much rain falls, the plants grow too rapidly, and do not sufficiently elaborate the blue pigment. Bright sunshine is most advantageous to its production.

The first cropping of the plants is the best; after two months a second is made; after another interval a third, and even a fourth; but each of these is of diminished value.

_Culture in India._--For the following excellent account of the modes of culture, and practice, &c., in Bengal, and other parts of India, I am indebted to Mr. G. W. Johnson, one of the correspondents of my "Colonial Magazine." Mr. Johnson, besides his own Indian experience, has consulted all the best authorities, and the opinions of contributors to the leading periodicals of Calcutta on this important subject:--

When America became known to Europeans, its indigo became to them a princ.i.p.al object of cultivation, and against their skill the native Hindostanee had nothing to oppose, but the cheapness of his simple process of manufacture. The profit and extent of the trade soon induced Europeans to brave the perils of distance and climate to cultivate the plant in Hindostan; but these obstacles, added to the superior article manufactured by the French and Spaniards in the West Indies, would long have held its produce in India in subordination, if the anarchy and wars incident to the French Revolution, especially when they reached St. Domingo, had not almost annihilated the trade from the West, and consequently proportionally fostered that in the East. The indigo produce of St. Domingo was nearly as large as that of all the other West India islands together. From the time that the negroes revolted in that island, the cultivation of indigo has increased in Hindostan, until it has become one of its princ.i.p.al exports, and the quality of the article manufactured is not inferior to that of any other part of the world.

The most general mode of obtaining the necessary supply of _weed_, as it is called by the planter, is as follows:--The land attached to the factory is parcelled out among the ryots or farmers, who contract to devote a certain portion of their farm to the cultivation of indigo, and to deliver it, for a fixed price per bundle, at the factory; a sum of money, usually equal to half the probable produce, has to be advanced to the ryot by the planter, to enable him to accomplish the cultivation, and to subsist upon until the crop is ready for cutting.

If, as is generally the case, sufficient land is not attached to the factory to supply it with plant, the owner obtains what he requires by inducing the ryots in his vicinity to cultivate it upon a part of their land. Yet it is with them far from a favorite object of cultivation; and, indeed, if it were not for the money advanced to each ryot by the planter, to provide seed, &c., and which gives him a little ready money, bearing no interest, it is doubtful whether he would engage in the cultivation at all. Even this advance of money does not induce him to appropriate it to any but the worst part of his farm, nor to bestow upon it more than the smallest possible amount of labor. The reasons for this neglect are valid, for the grain crops are more profitable to the ryot, and indigo is one of the most precarious of India's vegetable products.

In Bengal the usual terms of contract between the manufacturer and the ryot are, that the latter, receiving at the time a certain advance of money, perhaps one rupee (2s.) per biggah, with promise of a similar sum at a more advanced period of the season, undertakes to have a certain quant.i.ty of land suitably and seasonably prepared for sowing, to attend and receive seed whenever occasion requires, and to deliver the crop, when called upon, at the factory, at a specified price per bundle or 100 bundles. The particular conditions of these contracts vary generally in Bengal; they amount to advancing the ryot two rupees for every biggah of land, furnishing him with seed at about one-third its cost, on an engagement from him to return whatever his lands may produce (which, as has been said, is generally none at all), at the price charged, and receiving the plant from him at six, seven, eight, or sometimes nine bundles for a rupee--much oftener the former than the latter rates. A ryot cultivating alluvial lands, and having no seed, can hardly ever repay his advances; but it does not follow that he has been a loser, for he, perhaps, could not value his time, labor, and rent altogether at half the amount; and as long as this system is kept within moderate bounds, it answers much better than private cultivation to the manufacturer, and has many contingent advantages to the cultivator.

In Tirhoot similar engagements are entered into with the ryots, who are there called _a.s.samees_. These engagements with a.s.samees are generally made in the month of September, on a written instrument called a _noviskaun_, by which they agree for a certain quant.i.ty of land, for five years, to be cultivated with indigo plant, and for which they are to be paid at the rate of six rupees per biggah, for every full field of plant measured by a luggie or measuring-rod. The luggie, it must be observed, varies in size throughout the district.

In the southern and eastern divisions of Tirhoot and Sarun it is eight-and-a-half to ten feet long; and in the northern and western from twelve to fourteen feet. The a.s.samee receives, on the day of making his _bundobust_, or settlement, three rupees advance on each biggah he contracts for, another rupee per biggah when the crop is fit to weed, and the remaining two rupees at the ensuing settlement of accounts. Exclusive of the price of his maul or plant, the a.s.samee is ent.i.tled to receive two or three rupees per biggah (as may be agreed on) for gurkee, or lands that have failed, as a remuneration for his trouble, and to enable him to pay his rent. The foregoing are the princ.i.p.al stipulations of the noviskaun, but the a.s.samee further engages to give you such land as you may select, prepare it according to instructions from the factory, sow and weed as often as he is required, cut the plant and load the hackeries at his own cost, and in every other respect conform to the orders of the planter or his aumlah (managing man). The a.s.samee is not charged for seed, the cartage of his plants, or for the cost of drilling. I should mention that a penalty is attached to the non-fulfilment of the a.s.samees engagements, commonly called _hurjah_, viz., twelve rupees for every biggah short of his agreement, and this for every year that the noviskaun has to run. This is, however, seldom recoverable, for if you sue the a.s.samee in court and obtain a decree (a most expensive and dilatory process), he can in most instances easily evade it by a fict.i.tious transfer of his property to other hands.

The planter generally finds it his interest to get the Zemindar of the village in which he proposes cultivating, to join in the noviskaun, as a further security; or he engages with a jytedar, or head a.s.samee, having several others subordinate to him, and for whose conduct he is responsible. But a still better system is lately gaining ground in this district, I mean that of taking villages in ticka, or farm, by far the best and cheapest plan that has ever been resorted to for the cultivation of indigo.

When the planter cultivates the ground himself, it is called in Tirhoot _Zerant_ cultivation. _Zerants_, or _Neiz_, are taken on a pottah or lease for five years, at the average rent of three rupees per biggah. The heavy cost attending this cultivation has occasioned its decrease in most factories in Tirhoot and particularly since the fall in prices. About a third, I believe, was the proportion it formerly bore to the whole cultivation of the district, but of late such factories only have retained it as cannot procure sufficient good land under the a.s.samewar system; but now that the plan of taking villages in farm is becoming more and more prevalent here, it is very likely that Zerants will be entirely abandoned. From all the information I have been able to collect, the cost of a biggah of Zerant (ten feet luggie) may be estimated at sixteen rupees; that of a.s.samewar is generally twenty-five per cent. less, both exclusive of interest, agents' charges, and private expenses.

It can only be the reluctance of the ryot to cultivate indigo that induces a manufacturer to grow it himself, for it has been found an expensive plan, profitable only when the dye is at its highest rate, and even then scarcely furnishing an adequate return. They not only could not cultivate so cheaply as the native laboring husbandman, but ordinarily had to engage extensive tracts of land, much of which was not suitable for their purpose, or, perhaps, for any other, and consequently, although the average rate of rent was even low on the whole, it const.i.tuted a very heavy charge on the portion from which they obtained their return.

In Oude there are three systems of obtaining a supply of the plant, viz., _Kush Kurreea_, _Bighowty_, and _Nij_; but the latter is a mere trifle in proportion to the others, and is, therefore, not worth mentioning. On the _Bighowty_ system, which prevails chiefly in the Meerut and Mooradabad districts, the planter advances for a biggah of _Jumowah_ (irrigated sowings) nine rupees, and for a biggah of _a.s.saroo_ (rain sowings) five rupees four annas. The next year's plant, or _khoonti_, becomes his on an additional payment of eight annas per biggah. He also supplies the seed at the rate of six seers per biggah, being almost double the quant.i.ty made use of in Bengal, but which is necessary to make up for the destruction of the plant the year following by the frost, white ants, hot winds, gra.s.s cutters, and, I may add, the village cattle, which are let loose to graze on the khoonte during the latter period, when not a blade of gra.s.s or vegetation is to be seen anywhere left.

The Bighowty system is a sadly ruinous one, as, independently of the attempts to a.s.similate a.s.saroo, at five rupees four annas, with _Jumowah_, at nine rupees per biggah, which is very easily effected if the planter is not very vigilant, he is obliged to maintain an extensive and imposing establishment of servants, not only to enforce the sowings, weeding, and cutting, but also to look after his khoonte, and protect it from being destroyed by bullocks and gra.s.s cutters, or from being ploughed up clandestinely by the Zemindars themselves.

The Kush Kurreea system again has its evils, as the planter never gets plant for the full amount of his advances, and hence often leads to his ruin.

_Soils._--Indigo delights in a fresh soil; new lands, of similar staple to others before cultivated, always surpa.s.s them in the amount and quality of their produce. Hence arises the superior productiveness of the lands annually overflowed by the Ganges, the earthy and saline deposits from which in effect renovate the soil.

The further we recede from the influence of the inundation, the less adapted is the soil for the cultivation of indigo. The staple of the soil ought to be silicious, fertile, and deep. Mr. Ballard, writing on the indigo soils of Tirhoot, says that high "s...o...b..," or light soils, are generally preferred, being from their nature and level less exposed to the risk of rain or river inundation; but they are difficult to procure, and, moreover, require particular care in the preparation. Next in estimation is "doruss," a nearly equal mixture of light earth and clay; a soil more retentive of moisture in a dry season than any other. "Muttyaur," or heavy clay soils, are generally avoided, although in certain seasons, with mild showers of rain, they have been known to answer. The safest selection I should conceive to be an equal portion of s...o...b.. and doruss. In a country, however, interspersed with jheels and nullahs, it is difficult to form a cultivation without a considerable mixture of low lands, more or less, according to the situation of the a.s.samee's fields. Great care should be taken, at all events, to guard against oosur lands, or such as abound with saltpetre; these can be most easily detected in the dry months. _Puchkatak_, that is, lands slightly touched with _oosur_, have been known to answer, as partaking more of the nature of _doruss_ soil; but the crop is generally thin, although strong and branchy.

There is another description of land that should be cautiously avoided. It goes by the name of _jaung_, and is a light soil, with a substratum of sand from six to twelve inches below the surface. The plant generally looks very fine in such fields till it gets a foot high, when the root touching the sand, and having no moisture to sustain it, either dies away altogether, or becomes so stunted and impoverished as to yield little or nothing in the cutting. Of the _daub_ or _dearab_ (alluvial) land, says Mr. Ballard, there is scarcely any in the district except what falls to the lot of my own factories, being situated on the banks of the Ganges and Great Gunduck. Of _bungur_, a stiff reddish clay soil, there is little in Tirhoot; it pervades the western provinces, and is best adapted for a.s.saroo sowings, which do not succeed in Tirhoot.

_Preparation of the soil._--The root of the indigo plant being fusiform, and extending to about a foot in length, requires the soil to be loosened thoroughly to that depth at least. Experience teaches that the fineness of the tilth to which the soil is reduced previously to the seed being committed to it, is one very influential operation for the obtaining a productive crop. Yet in some districts of Bengal, particularly about Furudpore, the sowing is performed without any previous ploughing. This is where the river, when receded, has left the soil and deposit so deep, that about October, or a little later, the seed being forcibly discharged from the sower's hand, buries itself, and requires no after covering by means of the rake or harrow.

In Tirhoot they are indefatigable in this first step of the cultivation. Mr. Ballard says, that the preparation of indigo lands should commence in September, as soon as the cessation of the rains will permit; and as we do not rely on rain for our sowings (as is the custom in Bengal and elsewhere, and irrigation is never resorted to, from the heavy expense attending it), our princ.i.p.al aim is to preserve as much moisture in the fields as possible. They should receive, for this purpose, not less than eight ploughings, besides a thorough turning up with the spade, after the fourth ploughing, to clear the field from stubble, gra.s.s and weeds. It is absolutely indispensable to get all this done on our light soils, especially before the end of October, and have the land carefully harrowed down, so as to prevent the moisture escaping.

Should there be heavy rains between the interval of preparing and sowing, it will be necessary to turn the fields up with either one or two ploughings, and harrow them down as before. If only a slight shower, running the harrow over them will be sufficient to break the crust formed on the surface, and which, if allowed to remain, would quickly exhaust the moisture. This, with the occasional use of the weeding-hook, is all that the lands will require till the time of sowing.--("Transactions of the Agri.-Hort. Society of Calcutta,"

vol. ii., p. 22.)

_Sowing_.--The time when the seed is committed to the soil varies in different parts of India, and, even in the same place, admits of being performed at two different seasons. The periods of sowing in Bengal are first immediately after the rains, from about the latter end of October. The rivers are then rapidly retiring within their beds, and as soon as the soft deposit of the year has drained itself into a consistency, though not solid enough to keep a man from sinking up to his knees in it, they begin to scatter the seed broadcast. This is continued until the ground has become too hard for the seed to bury itself; the plough is then used to loosen the crust, and the sowing continued to about the middle, or even the end of November, from which period the weather is considered too cold, until February. These autumnal sowings are called October sowings, from the month in which they generally commence. Much of the plant perishes during the months of December and January, and more again in the spring, unless there are early and moderate showers. The crop that remains is not so productive ordinarily in the vat, as that obtained from spring sowings, and some think the quality of the produce inferior. But there is no expense of cultivation, and the liabilities of the crop to failure are such a discouragement to cost and labor in rearing it, that the October sowing is followed by most planters who can obtain suitable land. The second period of sowing is the spring, with the first rains of March, or even the end of February. The land having been measured and placed under its slight course of tillage during the two or three preceding mouths, is sown broadcast as soon as the ground has been well moistened, or even in prospect of approaching rain. The quant.i.ty of seed used for this autumn sowing is generally more than what is considered requisite for spring sowing; six seers at the former and four at the latter season per biggah, in Bengal, is the quant.i.ty usually allowed.

Some cultivators commence the autumn sowing as early as at the close of September, or as soon as the low lands are in a state to permit the operation after the inundation has subsided. This seed time may be said to continue until the end of December, and the crops from these sowings often yield an average produce, if the lands are not very low and wet. If they are, the sowing had better be delayed until January, or even February, for the crops from these latter sowings are usually the most productive, and the dye obtained from them the finest. The object for thus delaying the sowing is, that the young plants may have a more genial season for vegetation. Those who prefer sowing earlier, and yet are aware of the importance of saving the young plants as much as possible from the comparative low temperature of the season, sow some other crop with their indigo.

Til, the country linseed, is good for this purpose in high lying soils. But I never knew an intermixture of crops that was not attended by inconveniences and injuries more than was compensated by the advantages gained.

The success of sowings during March and April is very doubtful. It depends entirely upon the occurrence of rain, which in those months is proverbially uncertain. If the season should be sufficiently wet, the sowing may be performed in May; but a June sowing is very rarely remunerating. The rains setting in during the latter part of this month so promote the growth of weeds, that the young plants are choked and generally destroyed. The exceptions only occur in high lands, in unusually propitious seasons, and ought never to be relied upon except when the earlier sowings have failed. To protract the manufacturing season, some planters begin sowing upon low lying lands in the hot season, for the chance of a crop at the commencement of the rains; and they sow at the close of the rains with the hope of, as it were, stealing another in the next year. In the western provinces sowing necessarily occurs in the dry weather, usually in March and April, though occasionally either a little earlier or later.

In Tirhoot the sowings commence about the latter end of February or the beginning of March, if by that time there is sufficient warmth in the atmosphere to ensure a healthy vegetation. Light soils are sown on one close ploughing; heavy soils on two, with from four to eight seers of seed, in proportion to the size of the biggah. After strewing the seed, the field should be harrowed down by two turns of the harrow, and then again by two turns more after the third day. In case of rain before the plant appears (which it ought to do on the sixth or seventh day), if a slight shower, the harrow should be used again; if very heavy, it were best to turn up the ground and re-sow.

If rain fall after the appearance of the plant, and before it has got past four leaves, and attained sufficient strength to resist the hard crust before alluded to, immediate recourse must be had to drilling. In fact, the closest attention is required to watch the state of the young crop for a month at least after the sowings; if it yield the least, or a.s.sume a sickly appearance, drills are the only resource. These, if applied in time, in all March, for instance, or before the middle of April at latest, are generally successful, not only in restoring plants, but recovering such as may have become sickly from want or excess of moisture, or any other cause. In dry seasons they have been known to give a crop when broadcast sowings have failed. Each drill, with a good pair of bullocks, should do five biggahs a day. They are regulated to throw from three to four seers per biggah, but the quant.i.ty can be increased or diminished at pleasure. The natives do not employ them in their grain sowings, but commonly adopt a contrivance with their own plough for sowing in furrows, whenever their fields are deficient in moisture. The drill employed in Tirhoot resembles considerably the implement known by that name in England. It is found not only to effect a great saving of seed, ten seers being there sown broad-cost on a biggah of 57,600 feet square, and only seven seers by this drill; but also materially to improve the quality and regularity of the growth of the plant. Experience has demonstrated, that the more lateral room the plants have, the more abundant is their produce of leaves, in which the coloring matter chiefly resides. The seed employed should always be as new as possible, for though, if carefully preserved, it vegetates when one year old, and even when nearly two years old has produced a moderate crop, yet this has been under circ.u.mstances of an unusually favorable season and soil. The plants from old seed rarely attain a height of more than a foot before they wither and die. As frauds are very likely to be practised by giving old seed the glossiness and general appearance of new, great circ.u.mspection should be shown by the planter, who does not grow his own, in obtaining seed from known parties.

Planters in the lower provinces are induced to use up-country seed, because, coming from a colder climate, it vegetates, and the plants ripen rapidly, so as to be harvested more certainly before the annual inundation, but they employ one-fourth more. Three seers per Bengal biggah are sufficient, if it is "Da.s.see" seed; but four is not too much if it is up-country seed. A Bengal biggah is only a third of the size of that of Tirhoot. If the weather is dry, the seed very often does not germinate until the occurrence of rain, and it has been known in a dry, light soil, to remain in the ground without injury for six weeks. If seasonable showers occur, the plants make their appearance in four days, or even less; and they must be watched, in order that they may be weeded on the earliest day that they are sufficiently established to allow the operation to be safely performed. In dry weather, it must not be done while they are very young, otherwise many of the seedlings will have their roots disturbed, and perish from the drought. However, not more than a fortnight should be allowed to pa.s.s, after the seedlings have appeared, before the weeds are carefully removed, and this clearing should be frequently repeated until the plants so overshadow the ground that they of themselves keep back the advance of the weeds.

The first weeding is best performed immediately after a shower of rain.

Irrigation is rarely adopted for the indigo crops in the lower provinces of Bengal, unless they happen to be grown in some situation very favorable to the operation, such as the bank of a river. It is much more attended to in the western provinces, and in Oude, the water being obtained from wells, which are dug in nearly every cultivated plot. In Oude, Mr. Ballard says that a biggah of land employs three persons to irrigate it, and occupies never less than six days. The ryot, or cultivator, requires for the work a pair of bullocks, which cost him at least 32s., a bucket made of a white bullock hide, at 2s., and a rope for 2s. more, both of which do not last him above a year. He never pays less than 8s. for the rent of a biggah of land near a well.

In Bengal the plant requires three months to attain its highest state of perfection for manufacturing, but is often cut, from necessity, within half that time; for the approach of the river compels the premature removal of the crop, unless, indeed, its growth has been so r.e.t.a.r.ded that it would not pay the expense of working. Most indigo factories have consequently to begin in June, or early in July, whenever they may have effected their spring sowings, and the labors of the season are commonly terminated by the middle or end of August.

When the plants begin to flower is considered the best time for cutting them, and this is just what the botanist would have suggested, because then the proper sap of all plants is most abundant, and most rich in their several peculiar secretions. A vividly green, abundant and healthy foliage, downy at the back, is the surest intimation of the plants being rich in indigo. Plants that are ready for cutting in July and August, are usually the most productive.

In the western provinces from sixteen to twenty maunds of plant is considered a good produce per biggah. In the upper provinces the produce of the best crop, which is sown directly the rains commence, is not more then ten maunds per biggah. The factory maund is equal to about seventy-eight pounds. One thousand maunds of plant are considered as producing quite an average quant.i.ty of indigo if this amounts to four maunds. Adopting another mode of estimate, Mr.

Ballard says, that in Bengal an average crop may he considered to be from ten to twelve bundles, over an extensive cultivation, in a good season, from each Bengal biggah; the sheaf or bundle being measured by a six-feet cord or chain. Speaking of the produce in Tirhoot, the same gentleman says the "luggie," or measuring rod, varies throughout the district. The common Tirhoot biggah, is, I believe, equal to two-and-a-half or three Bengal biggahs (about an English acre). Its produce varies according to the size of the luggie, the fertility of the soil, and accidents of season; eight to ten hackery loads, however, is generally considered a good average return. South and east of Tirhoot, one hundred maunds from six hundred biggahs, including "khoonti," or a second cutting, is reckoned a successful result. In another part of the district, including Sarun, where the "luggie" is larger, the average produce is about one-third better.

As we measure our plant on the ground (he adds), the bundle system is unknown here; but, I believe, forty-five or fifty Tirhoot hackery loads of plants (estimated to yield a maund of dry indigo), will be found equal to two hundred Bengal bundles.--("Trans. Agri. Hort.

Soc., vol. ii. p. 23.")

In Oude the _jamowah_, or crop sown in May, yields on an average twenty maunds, or say thirteen bundles, per biggah (160 feet square). The "a.s.saroo," or rain sowings, producing a very inferior plant, the average return is not more than three maunds, or two bundles. The "khoonti," or crop of the next year from the same plants, averages fifteen maunds, or ten bundles per biggah.

In Central and Western India, the plants are allowed to produce the second and even the third year, according to some statements; but in Bengal the same stocks are rarely suffered to yield a second crop: being nearly all on lands that are under water in the height of the inundation, the stock is rotted in the ground. Mr. Ballard, speaking of the duration of the plant, says that, as for three years' plant and "khoonti," it is a mere chimera, like the many others with which the planters have hitherto deluded themselves, and which it only requires a little reflection to overthrow. A biggah may be cut here and there, on an extensive cultivation, but it can never be relied upon as forming a part of the cultivation.

The uncertainty of the indigo crop has been already noticed, and is, indeed, as proverbial as that from the hop plant in England. In Bengal the crop is particularly subject to be destroyed by the annual inundation of the river, if it occurs earlier than usual. A storm of wind, accompanied by rain and hail, as completely ruins the crop as if devoured by the locust; neither from this latter scourge is the crop exempt.

This p.r.o.neness to injury extends throughout its growth. The seedlings are liable to be destroyed by an insect closely resembling the turnip-fly, as well as by the frog. Caterpillars feed upon the leaves of older plants, and the white ant destroys them by consuming their roots. To these destructive visitations are to be added the more than ordinary liability of the plant to injury, not merely from atmospheric commotions, but even from apparently less inimical visitations. Thus not only do storms of wind, heavy rains, and hail, destroy the indigo planter's prospects, but even sunshine, if it pours out fervently after showers of rain, is apt, as it is properly termed, to _scorch_ the plants; and if it occurs during the first month of their growth, is most injurious to their future advance.

The reason of this effect appears to be the violent change from a state of imbibing to a rapid transpiration of moisture. No human invention or foresight can preserve the crop from the atmospheric visitations. To destroy and drive away the little coleopterous insects which attack the seedlings, it would be a successful method to spread dry gra.s.s, &c., over the surface intended to be cultivated, and to burn the litter immediately before the sowing.

The heat and smoke produced has been found perfectly efficacious against the turnip-fly in England. To destroy the caterpillar, slacked lime dusted over the leaves, while the dew is upon them, is an effectual application. The white ants may be driven away or destroyed by frequent hoeings, which is the best preventive of the scorching, for hoeing preserves the soil in an equable and fitting state of moisture.

The great supply of seed for Bengal cultivation is obtained from the western provinces, and forms an article of trade of no inconsiderable magnitude. The stubble in the low lands of Bengal is generally submerged before it has time to throw out fresh shoots, on which the blossom and subsequent seed-pod are formed. There are, however, some high tracts reserved for that purpose, and on these the plant is found well in flower in September, and the seed fit to gather in November or early in December.

Two methods are pursued to extract the indigo from the plant; the first effects it by fermentation of the fresh leaves and stems; the second, by maceration of the dried leaves; the latter process being most advantageous. They are thus described by Dr. Ure, in his "Dictionary of Arts and Manufactures:"--

1. _From the recent leaves._--In the indigo factories of Bengal, there are two large stone-built cisterns, the bottom of the first being nearly upon a level with the top of the second, in order to allow the liquid contents to be run out of the one into the other.

The uppermost is called the fermenting vat, or the steeper; its area is twenty feet square, and its depth three feet; the lowermost, called the beater or beating vat, is as broad as the other, but one-third longer. The cuttings of the plant, as they come from the field, are stratified in the steeper, till this be filled within five or six inches of its brim. In order that the plant, during its fermentation, may not swell and rise out of the vat, beams of wood and twigs of bamboo are braced tight over the surface of the plants, after which water is pumped upon them till it stands within three or four inches of the edge of the vessel. An active fermentation speedily commences, which is completed within fourteen or fifteen hours; a little longer or shorter, according to the temperature of the air, the prevailing winds, the quality of the water, and the ripeness of the plants. Nine or ten hours after the immersion of the plant, the condition of the vat must be examined; frothy bubbles appear, which rise like little pyramids, are at first of a white colour, but soon become grey, blue, and then deep purple red. The fermentation is at this time violent, the fluid is in constant commotion, apparently boiling, innumerable bubbles mount to the surface, and a copper colored dense sc.u.m covers the whole. As long as the liquor is agitated, the fermentation must not be disturbed, but when it becomes more tranquil, the liquor is to be drawn off into the lower cistern. It is of the utmost consequence not to push the fermentation too far, because the quality of the whole indigo is deteriorated; but rather to cut it short, in which case there is, indeed, a loss of weight, but the article is better. The liquor possesses now a glistening yellow color, which, when the indigo precipitates, changes to green. The average temperature of the liquor is commonly 85 deg. Fahr.; its specific gravity at the surface is 1.0015; and at the bottom 1.003.

As soon as the liquor has been run into the lower cistern, ten men are set to work to beat it with oars, or shovels four feet long, called _busquets_. Paddle wheels have also been employed for the same purpose. Meanwhile two other laborers clear away the compressing beams and bamboos from the surface of the upper vat, remove the exhausted plant, set it to dry for fuel, clean out the vessel, and stratify fresh plants in it. The fermented plant appears still green, but it has lost three-fourths of its bulk in the process, or from twelve to fourteen per cent. of its weight, chiefly water and extractive matter.

The liquor in the lower vat must be strongly beaten for an hour and a half, when the indigo begins to agglomerate in flocks, and to precipitate. This is the moment for judging whether there has been any error committed in the fermentation, which must be corrected by the operation of beating. If the fermentation has been defective, much froth rises in the beating, which must be allayed with a little oil, and then a reddish tinge appears. If large round granulations are formed, the beating is continued, in order to see if they will grow smaller. If they become as small as fine sand, and if the water clears up, the indigo is allowed quietly to subside. Should the vat have been over-fermented, a thick fat-looking crust covers the liquor, which does not disappear by the introduction of a flask of oil. In such a case the beating must be moderated. Whenever the granulations become round, and begin to subside, and the liquor clears up, the beating must be discontinued. The froth or sc.u.m diffuses itself spontaneously into separate minute particles, that move about the surface of the liquor, which are marks of an excessive fermentation. On the other hand, a rightly fermented vat is easy to work; the froth, though abundant, vanishes whenever the granulations make their appearance. The color of the liquor, when drawn out of the steeper into the beater, is bright green; but as soon as the agglomerations of the indigo commence, it a.s.sumes the color of Madeira wine; and speedily afterwards, in the course of beating, a small round grain is formed, which, on separating, makes the water transparent, and falls down, when all the turbidity and froth vanish.

The object of the beating is three-fold; first, it tends to disengage a great quant.i.ty of carbonic acid present in the liquor; secondly, to give the newly-developed indigo its requisite dose of oxygen by the most extensive exposure of its particles to the atmosphere; thirdly, to agglomerate the indigo in distinct flocks or granulations. In order to hasten the precipitation, lime water is occasionally added to the fermented liquor in the progress of beating, but it is not indispensable, and has been supposed capable of deteriorating the indigo. In the front of the beater a beam is fixed upright, in which three or more holes are pierced, a few inches in diameter. These are closed with plugs during the beating, but two or three hours after it, as the indigo subsides, the upper plug is withdrawn to run off the supernatant liquor, and then the lower plugs in succession. The state of this liquor being examined, affords an indication of the success of both the processes. When the whole liquor is run off, a laborer enters the vat, sweeps all the precipitate into one corner, and enters the thinner part into a spout which leads into a cistern, alongside of a boiler, twenty feet long, three feet wide, and three feet deep. When all this liquor is once collected, it is pumped through a bag, for retaining the impurities, into the boiler, and heated to ebullition. The froth soon subsides, and shows an oily looking film on the liquor. The indigo is by this process not only freed from the yellow extractive matter, but is enriched in the intensity of its color, and increased in weight. From the boiler the mixture is run, after two or three hours, into a general receiver called the _dripping vat_, or table, which, for a factory of twelve pairs of preparation vats, is twenty feet long, ten feet wide, and three feet deep, having a false bottom two feet under the top edge. This cistern stands in a basin of masonry (made water-tight with Chunam, hydraulic cement), the bottom of which slopes to one end, in order to facilitate the drainage. A thick woollen web is stretched along the bottom of the inner vessel, to act as a filter. As long as the liquor pa.s.ses through turbid, it is pumped back into the receiver; whenever it runs clear, the receiver is covered with another piece of cloth to exclude the dust, and allowed to drain at its leisure. Next morning the drained magma is put into a strong bag, and squeezed in a press. The indigo is then carefully taken out of the bag, and cut with a bra.s.s wire into bits, about three inches cube, which are dried in an airy house, upon shelves of wicker work. During the drying a whitish effloresence comes upon the pieces, which must be carefully removed with a brush. In some places, particularly on the coast of Coromandel, the dried indigo lumps are allowed to effloresce in a cask for some time, and when they become hard they are wiped and packed for exportation.

2. _Indigo from dried leaves._--The ripe plant being cropped, is to be dried in sunshine from nine o'clock in the morning till four in the afternoon, during two days, and threshed to separate the stems from the leaves, which are then stored up in magazines till a sufficient quant.i.ty he collected for manufacturing operations. The newly dried leaves must be free from spots, and friable between the fingers. When kept dry, the leaves undergo, in the course of four weeks, a material change, their beautiful green tint turning into a pale blue-grey, previous to which the leaves afford no indigo by maceration in water, but subsequently a large quant.i.ty. Afterwards the product becomes less considerable.

The following process is pursued to extract indigo from the dried leaves:--They are infused in the steeping vat with six times their bulk of water, and allowed to macerate for two hours, with continual stirring, till all the floating leaves sink. The fine green liquor is then drawn off into the beater vat, for if it stood longer in the steeper, some of the indigo would settle among the leaves and be lost. Hot water, as employed by some manufacturers, is not necessary. The process with dry leaves possesses this advantage, that a provision of the plant may be made at the most suitable times, independently of the vicissitudes of the weather, and the indigo may be uniformly made; and, moreover, that the fermentation of the fresh leaves, often capricious in its course, is superseded by a much shorter period of simple maceration.

PRODUCTION OF INDIGO IN INDIA.

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1840 120,000 1841 162,318 1842 79,000 1843 143,207 1844 127,862 1845 127,862 1846 101,328 1847 110,000 1848 126,565 1849 126,000