NATIVE AND EUROPEAN METHODS 





Pmrtag. 



INDIGOFERA 



Manufacture : 

 WctProoaM 



tin- hand beating has been to a certain extent replaced by Machinery. 

 !n'. it in:'. Whore this is employed, there is a single beating vat 

 wlnrh runs tin- length of the range of vats and is divided along itH length 



in two walls, the number depending on whether one or two ben 

 wheels are employed. These walls stop short of the two ends of the vat 

 and urv simplv employed to give din-etion to the circulation set up by 

 tin- \\heels. The wheels themselves consist of small flat discs of wood 

 at tin -hoi to the ends of a number of spokes radiating from the axle. By 

 this method beating is complete in about one hour. More recently the 



us: has lii-eii replaced by blowing a mixture of air and steam through Blowing. 

 the liquor ; and, later still, in 1902, this process, modified so as to blow 

 ammonia through the liquor, was introduced by Rawson. Neither of these Ammonia. 

 hitter processes have, however, been universally adopted, and the wheel 

 beating is still most commonly employed. 



tor beating is complete, the liquor is allowed to stand until the 

 precipitated indigo the mal has settled, leaving a clear, red, supernatant xoi. 

 liquor. This ' mail/a pani ' is drained off and the residual ' mal ' is 

 pumped into boilers where it is mixed with clean water and boiled, either Boiling. 

 hv the direct action of heat or by injecting steam. The boiling and sub- 

 sequent stages in the manufacture take place within the factory building. 

 When the boiling is complete, the contents of the boilers are run on to the 

 ' table.' This consists of a heavy canvas sheet which has been previously 

 wetted and spread on a support of split bamboo. The cloth acts as a Filtering. 

 filter, allowing the clear water to drain off and retaining the indigo as a 

 thick paste which is now transferred to the press. This is a square 

 wooden box, the walls and bottom of which are perforated by numerous 

 holes. The interior is lined with damp cloth and the mal is then poured 

 in to a depth of 8 or 9 inches. The lid, which fits the interior accurately, 

 is then put on and screwed home by means of a screw worked by a long 

 lever. This is turned at intervals during 5 to 6 hours, in which time the 

 mal will be pressed into a hard cake 3 to 3 inches thick. The sides 

 of the press are now removed and the cake is transferred to a table where 

 it is cut by wire into cubes of about 3 inches. These are removed and 

 placed on open shelves to dry in an airy room. The air admission is so 

 regulated that slow drying is effected. This is essential if cracking and Drying. 

 subsequent breakage of the cakes are to be avoided. During the process 

 of drying, the cake becomes covered with a dense growth of mould. Before 

 packing this is brushed off by coolies. The final stage consists in packing Packing. 

 the dried and cleaned cakes into specially constructed cases which are 

 weighed and forwarded to Calcutta for disposal " (Leake). 



DRY PROCESS. The wet method just described by Leake is that 

 which is almost universally employed, though in Madras the dry-leaf 

 process is still pursued to a limited extent. From the historic chapter 

 given above it will be seen, moreover, that during the first century of the 

 industry as fostered by the East India Company, the dry process was 

 apparently universally adopted. It was even upheld that to that fact F 

 was attributable the high merit of the Indian as compared with other 

 indigoes the stems and twigs used in the wet vat system detracted, so it 

 was then believed, very greatly from the merit of the dye. During the 

 second century, when the industry had been conveyed from the West 

 Indies back to India, or rather to Bengal, the wet process was alone that 

 employed. It is significant that throughout all this rise and fall of the 



681 



Cutting into 

 CMML 



Dry 



Process. 



