248 CALYCIFLOR^E. 



on a white soup plate. A quantity of lime water is now added, 

 and the blue floccules are allowed to subside. The clear water 

 is then drawn off by plugs placed at different heights in the 

 cistern, and the sediment is drained in sieves made of horse 

 hair. It is after this put into coarse linen bags, and having 

 remained for some time suspended in the shade, is subjected to 

 pressure in order to get rid of as much of the moisture as 

 possible. Lastly the Indigo, having been converted into a stiff 

 consistent mass, is cut into small squares, and allowed to dry in 

 the shade. 



The 2nd method of manufacturing Indigo is known by the 

 name of the scalding process. It appears to be a revival of the 

 ancient Indian mode, as practised at Ambore, and described by 

 Col. Martine in the third volume of the Asiatic reseai'ches. He 

 there mentions, that the natives boil the plant in earthen pots 

 of 18 inches diameter, till the colouring matter has been ex- 

 tracted : it is then removed into larger jars, and agitated by 

 means of a bamboo, until a granulation of the fecula takes place. 

 A precipitant of red earth and water is then added, and the 

 fecula is allowed to subside. The clear liquid is lastly drawn 

 off, and the Indigo is dried in small bags suspended in the shade. 



The modern process is conducted on similar principles. 

 Large coppers are about two- thirds filled with the branches of 

 the Indigo, which are not to be pressed down. Cold water is 

 then added to within a few inches of the brim, and the fire is 

 lighted and kept up rather briskly, till the liquor acquires a 

 deep green colour. During this part of the process, the mass 

 must be constantly stirred, otherwise the bottom will be over- 

 scalded before the surface is ready. The fire is now to be 

 withdrawn, and the liquor passed through a hair-cloth into the 

 beating vat, where it must, while still hot, be agitated in the 

 common way for half an hour. Lime water is now to be added, 

 and after standing for about two hours and a half, the superna- 

 tant liquor, which is of a Madeira wine colour, is to be drawn 

 off'. The rest of the process is similar to that followed in pre- 

 paring common fermented Indigo. 



The advantages of the scalding over the fermenting process, 

 are, according to Dr Roxburgh, that: — 1. The produce is 

 larger. 2. Tiie health of the labourers is not endangered by 

 the noxious effluvia, as is the case in the fermenting process. 

 3. Much less agitation, and very little precipitant is neces- 

 sary. 4. The operation may be performed several times in 

 the course of the day. 5. The Indigo dries quickly, without 

 acquiring a bad smell. 6. Indigo so prepared has not the flinty 

 appearance common to fermented Indigo, but in softness and 

 levity is equal to Spanish^ora. 



The 3d manner of manufacturing Indigo is called the dry 

 process, and is that at present followed in the large factories in 

 the southern provinces of India. It is described at great length 



