128 SCIENTIFIC REPORTS OE THE AGRICULTURAL RESEARCH 



cipitation; mere storage in reservoirs also reduces them in 

 quantity. Most factories use their khazanas or reservoirs 

 as settling tanks, drawing oft' the water from the top by 

 surface drainers; this is intended to remove suspended mud 

 which would contaminate the indigo, but an extension of 

 the method would undoubtedly serve to reduce the bacterial 

 numbers, and in cases where bad fermentation sometimes 

 followed by bad settling in the beating vat is a common 

 experience of the factory, the use of khazanas of greater 

 capacity and designed to effect more complete settling of 

 the suspended matter in the water, would almost certainly 

 lead to improved manufacture. Larger reservoirs would 

 also reduce the proportion of water directly pumped with- 

 out settling from the river or lake, which in many cases 

 appears to be responsible for bad fermentation. It is a 

 frequently observed fact that certain vats habitually give 

 better fermentation than others in the same factory; vari- 

 ous explanations have been given of this difference but the 

 following one which does not seem to have been suggested 

 appears to fit in with the conditions in many cases. In 

 many factories the khazana is not large enough to supply 

 water to all the vats in use at one time, so that a certain 

 number of the latter are filled with water which has stood 

 for several hours in the khazana, the remainder being 

 watered by practically direct pumping from the outside 

 source, whether river, lake, or tank. This would at once 

 tend to create differences in the bacterial content of the 

 steeping vats, which might very well be of a sufficiently 

 high order to produce variations in the fermentation going 

 on in the latter. Such variations would be reduced together 

 with the number of bacteria by the use of khazanas of ade- 

 quate capacity, allowing of settling the whole amount of 

 water used each day. It is suggested that the not infre- 

 quent superiority of the yield of small factories and small 

 vats may be traced to the very generally adequate size of 

 their khazanas. 



Apart from the bacteria present in the water it is to be 

 remembered that the plant itself introduces an enormous 



