salt, would be lost; if on the other hand, it was agitated too long, the different parts would be again mixed and form a new combination, and the salt reacting on the dregs would excite a second fermentation, that would alter the dye, spoil its colour, and make what is called burnt indigo. The precaution consists in the attention of the manufacturers from time to time to drawing off a little to examine in a clean vessel; when they perceive that the coloured particles are separated from the rest of the liquor, they leave off shaking the buckets, to allow time to the blue dregs to precipitate to the bottom of the tub, where they are left to settle till the water is quite clear. After the superfluous liquor is run off, the dregs remaining at the bottom having acquired the consistence of a thick muddy liquid, it is then drawn off into a settler; after it is again cleared of its superfluous liquid, it is drained into sacks, from whence, when water no longer filters through the cloth, and it becomes of a thick consistence, it is put into chests, where it entirely loses its moisture, and at the end of three months is fit for sale.

That which is known by the name of Guitamala indigo, the name of the place whence it comes, is the most perfect of all. There are several sorts made in the East-Indies, but that from the Isle of Java is the best, but its price renders it little used by dyers. The best ought to float on the surface of the water, and its colour ought to be a very dark blue inclining to violet, bright and sparkling, especially when broken. It may be tried by dissolving a little in a glass of water; if pure, it will mix equally, but if not, it will separate and fall to the bottom; the pounded is much more subject to adulteration than that sold in cakes.

The following account of an essential improvement in the preparation of indigo, is a translation from the French of citizen Balley. It will undoubtedly be heard with astonishment, that although indigo has been manufactured during the space of nearly a century, its preparation still consists in such imperfect approximations, that amongst the best manufacturers, even ten, fifteen, and twenty tubs fail out of a hundred. Sometimes, either owing to want of experience, or the contrarieties of temperature, even a much larger number of tubs fail, and ruin the proprietor;

but through the exertions of the colonial proprietor of St. Domingo, Nazon, a means of preventing this failure is laid down. After describing the first process of cutting and macerating plants, similar to the one before related, he thus proceeds: "To bring the maceration to its ultimate point requires from fifteen to thirty-six hours, according to the temperature of the atmosphere at the time of the operation. It is also necessary to take into the consideration, the quality of the indigo plant, the nature of the soil that has produced it, and that of the water in which it is immersed. The first indication from which it is judged, that the process of maceration approaches its ultimate point, is the sinking of the scum, which has elevated itself into the space of about half a foot, which was left unfilled in the vat. When this scum has become a kind of crust, of a copper blue colour, it is then thought to be sufficiently macerated. However this plan was often insufficient, and there was another method on which greater reliance could be placed; this consisted in drawing off a small quantity of the water, by means of a cock in the lower part of the vat; this being received in a silver cup, notice is taken whether the fecula tends to precipitate itself to the bottom of the cup, from whence the maceration is then supposed to be perfect. Such was the process most generally practised, but it often led into error. To avoid this, we have seen means, which consists in accurately observing the water contained in the cup; five or six minutes after it has been poured therein, it forms round the sides a ring or edge, which is at first of a green colour, but afterwards it becomes blue. So long as the maceration has not produced its proper effect, this ring detaches itself with difficulty from the sides of the cup, but at last it is seen to precipitate and concentrate itself at the bottom of the vessel, always toward the centre, under the water, which is become limpid, though with a yellowish tinge. When these appearances are observed, they infallibly indicate the success of this first operation. The water is then drawn off into a second bason or tub, placed beneath the first. This second tub is termed the batterie, as its use is for beating the water, still charged with the fecula. In order that it may separate quickly, it is agitated, either by hand labour or the pow

er of a mill, taking care not to agitate it too long, in which case the fecula would be remixed with the water, and instead of indigo, nothing more than muddy water would be produced; but to avoid this, it only requires attention. It is afterwards drawn off from the batterie, to a third or smaller receiver, called the diablotin; we then find the batterie covered with a very liquid blue paste, which is put into bags of coarse linen cloth of the form of inverted cones, which suffer the watery parts to run off; these bags are afterwards emptied of their contents upon tables in the drying rooms, where this blue paste is kneaded, and after it has acquired a denser consistence, it is spread out and cut into small squares, in order that it may dry the sooner; after which it is ready for sale.* .*

A set of expériments on the solution of indigo, in different kinds of sulphuric acid [oil of vitriol] were made by Mr. Bucholz, in 1805, who found that the British sulphuric acid was a bad solvent, unless it had been previously boiled with sulphur; that the acid manufactured in the north of Europe dissolved it well in its natural state; but when deprived of the sulphurous acid gas, it became as inefficacious as the English. Hence it appears, that the presence of this gas promoted the solution; of course the common sulphuric acid, in the state in which it is usually employed by the dyers, namely, blackened with vegetable matter, answers their purpose better than the purest.

[For the following original account of indigo, as an article of trade, the Editor is indebted to a commercial friend in this city.] THE Commercial world is supplied with indigo from Manilla, Batavia, Bengal, and Isle of France; likewise from Lima, and Guatimala ;-from most parts and ports in the province of Caraccas; from St. Domingo, from New-Orleans, and from SouthCarolina. Of all these sources, Guatimala, Bengal, and Caraccas are the most abundant, and their quality vastly superior. Manilla formerly produced a considerable supply, and was once es

The above mode of preparing indigo is different from that given by Bry an Edwards in his account of the West-Indies, to which the cultivator ought to have recourse. EDITOR.

teemed on account of the richness of its dye; for some years past it has decreased in quantity and quality. Batavia does not afford a quantity worthy of mentioning, and its quality is various,

Bengal manufactures a very large quantity; when exported it is packed in chests, weighing from 100 to 250 pounds net; it is subject to sworn inspection, and differs more in price than any description of indigo. I have seen Bengal indigo not much inferior to the very best of Guatimala, but the general run of their first qualities is about equal to the Sobriente of Caraccas: their middling is equal to Isle of France; and their inferior ranks with that made at New-Orleans. Bengal indigo finds a ready sale at most of the European markets; it is put up in square pieces.

The Isle of France formerly produced a considerable supply, but the effects of the revolution have reduced the quantity so, that the Island is not any longer looked to for any supply of consequence.

The interruption of trade with Lima, occasioned as well by the present war as the revolutions in old and new Spain, has prevented any supply of indigo from that quarter.

Guatimala has long afforded to the commercial world, a very extensive and rich supply of indigo. Its quality, generally speaking, is superior to all others; and there appears to be more dye and better colours produced from this indigo: when prepared for use from the vats, its form is in small pieces of very singular size and shape, but remarkable for their firmness and consisten-⚫ cy; its package is in seroons, a species of bale made from a hide, and originally shaped when the skin was in a humid state; their weights are various, from 100 to 240 pounds Spanish weight. Indigo at Guatimala is subject to inspection, and the scroons haye marks, descriptive of their various qualities.

The qualities are Flora, Sobriente, and Cortes--the meaning of which as well describes their value as their colour. Flora, or Fleur, is that indigo which produces the most exquisite blue; and which, on being pressed between your fingers, instantly pulverizes into the finest particles. Of this quality, their inspectors make three grades.

The second quality, Sobriente, signifies purple; its dye is not either as rich or as deep in colour as the Flores; but as the quantity is much larger than the first sort, and as its application is more various, this description of indigo meets with a more ready sale. Inspectors make likewise three grades of this quality.

The third quality is called Cortes, which signifies copper. It is the lowest kind of indigo, and used for inferior purposes; it is liable to the same remarks on the subject of inspection, as the two preceding.

In times of peace, the indigo produced in this extensive part of the Spanish dominions, is all shipped to Old Spain: it is transported from Guatimala to Bodigas Altas in Gulfo Dulce; and from thence carried to the mouth of that wonderful largoon which empties itself into the Bay of Honduras. Ships of 100 guns can lay with safety off the entrance, but none can enter that draw more than from 5 feet 6 inches to 6 feet water. When over the bar, there is 15 fathom water.

Caraccas indigo, as it is generally called, from being the produce of that extensive province, is shipped from La Guira and Porto Cavello, and generally from all the ports in the Spanish Main. The quality of this indigo is somewhat inferior to that of Guatimala; but this difference is not great, as the European prices current will prove. There is an inspector at Caraccas; but since the existence of the present war, I have seen large quantities without the inspector's mark. There are three quali、 ties, and of these the inspectors make on the two first three grades, and on the last two, the following marks:

In purchasing the article, where an inspection has taken place,

these marks may prove very serviceable. The seroon generally