110 SCIENTIFIC REPORTS OF THE AGRICULTURAL RESEARCH 



hot water extraction, but the economics of this method 

 would have to be worked out before recommending its adop- 

 tion as a factory procedure. 



it became clear very early in this enquiry that no advance 

 could be made in the absence of an experimental factory. 

 Designs were accordingly made and sanction obtained for 

 the necessary expenditure; it is unfortunate that owing to 

 various and numerous sources of delay it has not been found 

 possible to complete the erection and equipment of the fac- 

 tory in time for manufacture of Java plant at the time when 

 it was ready for cutting; it is hoped that even with over- 

 mature plant some results of value may be obtained. The 

 factory consists of one range of six vats with six corre- 

 sponding separate khazanas and blowing vats. Four vats 

 are of 100 cubic feet capacity and two of 50 cubic feet. 

 Blowing was preferred to beating on account of the mechan- 

 ical difficulties of the latter in several small vats, and of the 

 greater possibility of controlling the oxidation and ensur- 

 ing comparable conditions in all the vats. 



Apart from the actual indigo produced the Indigo 

 Research Chemist has kindly undertaken to arrange for 

 complete analytical control of the whole series of operations 

 in each experiment which will naturally afford more insight 

 into the causes underlying differences in the results obtained 

 by variations in the method of manufacture than could be 

 secured merely by weighment of the indigo produced. 



The lines of enquiry which will be adopted will aim at 

 determining : — 



(1) The possibility of increasing the yield of indigo by 



introducing specific bacteria into the steeping 

 vats. 



(2) The best way of doing this on a factory scale and 



under factory conditions. 



There are indications that the second part of this 

 enquiry will form the major problem and may require a 

 considerable amount of time and labour to bring to a suc- 

 cessful issue. It is also evident that should hot water 

 extraction prove economically feasible the difficulties 



