INDIGO. 



501 



of Indigo was opened liy the French, who then 

 began to import cotton and indigo from their 

 settlement at Goree, on the coast of Africa. This 

 dye was pronounced by the English dyers to be 

 almost equal to that of Guatiraala, and superior 

 to every kind of West India indigo. 



Englandjthough now occupying so commanding 

 a position in the commercial and manufacturing 

 world, was for a long time slow not only in ori- 

 ginating inventions and improvements, but even 

 in adopting those of other nations. A long 

 period elapsed after the discovery of America, 

 before indigo began to take its rank among the 

 most useful ingredients of the English dye-house. 

 Richard Hakluyt, at the close of the sixteenth 

 century, mentions it as an object deserving of 

 inquiry, as at that time it was not known in 

 this country what plant produced the indigo. 

 Instructions were therefore given to discover 

 whether " Anile, that blue colour, be a natural 

 commodity, or, if it be compounded of an herb, 

 to send the seed or root with the order of sow- 

 ing." The French name of indigo is anil ; it is 

 known under that term, or simply nil, in South 

 America, whence it was adopted by the French 

 and Portuguese. It is remarkable that Nile is 

 the Arabic name of the same plant. The name 

 by which it is designated in English is evidently 

 a con-uption of the ancient indicum, but on its 

 first introduction into England from America, it 

 was usually known as anil. In Chinese it is 

 called tien haam, which signifies sky blue. 



Indigo from America was for a long period 

 very superior to that obtained from the East ; 

 and although this dyeing ingredient was recog- 

 nised in commerce as coming from the East 

 Indies, it was imported thence in small quanti- 

 ties, and of so indifferent a quality, as not in any 

 way to compete with the western production. 

 Scarcely twenty years ago, this was the relative 

 position of the indigoes from America and Asia. 

 Since then the judicious and spirited exertions 

 of a few enlightened individuals, have shown, 

 that by careful cultivation and preparation, its 

 character might be essentially improved in the 

 British possessions in India. At the present 

 day this article ranks among the most important 

 objects of our commerce with the East Indies, 

 while its quality has been raised far above that 

 received from South America. 



Indigo has long been cultivated in Spain, but 

 is on the decline in that country, owing to the 

 more favourable circumstances attending its cul- 

 tiire in the East and West Indies. During the 

 reign of Bonaparte, and his attempted restric- 

 tions of commerce, it was also tried in the south 

 of France and Italy, but proved a failure. 



Tlie colouring matter is obtained from the 

 whole plant. There are two modes used for its 

 extraction — it is fermented, or it is scalded. The 

 first method is universally practised in South 



America and the West Indies ; and almost 

 wliolly by the English factors in the East. 



In an indigo house, where the fermenting 

 process is pursued, the chief apparatus consists of 

 three wooden vats of different sizes, placed on 

 different levels, so that the contents of the first 

 may flow into the second, and those of the second 

 into the third. Tlie plants, on being cut, are 

 laid in the first or steeping vat, in sufficient 

 quantity to fill it without receiving pressure, 

 and water is poured over them ui;til it rises about 

 three inches above the level of the top plants. 

 A frame of heavy wooden bars is then laid on 

 the vat to prevent the plants from rising when 

 in fermentation. This state is generally induced 

 in less than eighteen hours. The contents swell 

 and foam; lai-ge bubbles of gas are formed, which 

 on being disengaged appear of a lively green, 

 and tinge the whole vat of the same colour. 

 When at the highest, the fermenting mass is 

 covered with a brilliant copper-coloured scum, 

 which passes into violet towards the end, but 

 the pulp and liquor remain green. The gas 

 given off during the process is inflammable. 

 The heaving of the scum is so powerful as often 

 to lift up the heavy wooden frame above men- 

 tioned. This fermentation is carried on for the 

 purpose of extracting all the grain or colouring 

 matter from the plant, and it is a nice point to 

 ascertain the exact period when it ought to 

 cease. If the fluid be drawn off too soon, much 

 of the pulp is left behind, and if too late, the 

 tender tops of the plant occasion putrefaction, 

 by which all the dye is destroyed. Many plans 

 have been suggested to discover to a scientific 

 certainty the most advantageous degree of fer- 

 mentation. Experiments were made at St 

 Domingo, when the French possessed that island, 

 under the sanction and encouragement of the 

 Chamber of Agriculture; but the unsatisfactory 

 result only served to convince practical men that 

 they could not with safety tnist to any test save 

 that of experience. In order to ascertain the 

 state of fermentation, it was recommended to 

 dip a pen, at intervals of every quarter of an 

 hour, into the contents of the vat, and to make 

 with it a few strokes on paper : when the marks 

 thus made are colourless, it is the proper period 

 for arresting the fermentation. Much practical 

 skill is required in seizing on this moment, in 

 which the fermenting mixture assumes the 

 appearance of a liquor, holding in suspension 

 a distinct green pulp, which by slight agitation 

 speedily and completely separates and falls to 

 the bottom, leaving a clear gold-coloured super- 

 natant fluid. The whole of the turbid green 

 liquor is then discharged from the steeping vat, 

 and passes into the second vessel. The first 

 vat is then immediately cleansed, fresh plants 

 are thro-mi in, and the work proceeds without 

 intermission. Tlie refuse matter is carefully 



