233 On the Manufacturing of Indigo in this Country. 



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it will require the product of eighty thousand acres to raise a sup- 

 ply for home consumption. 



There are four points to be attended to in the making of indigo^ which 

 require much judgment, aided by practical skill. These are, the 

 time of cutting the plant, the degree of fermentation to be given in 

 the steeper, the degree of oxidisement of the coloring feculse, and 

 the extrication of foreign matter from the pulp after the indigo is 

 made. Three of these processes being purely chemical, it is not 

 therefore, surprising, that ordinary workmen should frequently fail in 

 producing a good article. There is probably more loss sustained by 

 our planters, from the ignorance of the operators, tlian the whole 

 value of the article now sold. 



The plant should be cut when at maturity, as it will then afford a 

 fine color ; but if cut too late, a portion of tlie color is then lost, and 



an indigo of worse quality is obtained. Mr. Dalrymple informed me, 



tljat the plant should be cut when in full flower, after tlie weather for 



some days has been dry. 



Another celebrated maker of indigo, asserts, " that If the plants 

 are suffered to stand till they run into flower, tlie leaves become too 

 dry and Iiard, and the indigo obtained from them proves less in quan- 

 tity and less beautiful — the due point of maturity is known by tlie 

 leaves beginning to grow less supple, or more brittle. 



It appears, that the makers of indigo differ as to the time of gath- 

 ering the plant. It is greatly to tlie interest of our planters that they 

 should ascertain, by direct experiment, the proper time of gathering 

 the plant. ' ^ 



When the plant is gathered, it has to undergo a process by immer- 

 sion in water, for the purpose of exti'acting its coloring matter. This 

 operation is performed in two ways — by fermenting the green plant 

 in a steeper, or by first dryhig the leaves and then simmering them 

 in a boiler. The latter process is now pursued by some of the best 

 makers in Bengal, and has apparently an advantage over the old 



process- 

 When tlie green plant is fermented m a steeper, and the process 

 is carried a litde too far, the coloring matter will become dark, 

 and is said to be burnt — if carried a slight degree fartlier it will be 

 black, and of course the indigo will be very much injured. Nine 

 tenths of the indigo made in tlie United States partakes more or less 



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of this character, and has evidently been injured by an excessive 

 fermentation. To observe a ^wo. degree of fermentation in the steep- 



