277 COTTER: SODA INDUSTRY OF SIND. 



In the cases of Lambro, Nainwaro, and the old chaniho heaps of 

 Dabhiwari, the so-called chaniho is mainly sulphate; the alkali 

 in the chaniho of Lambro must be largely natron or a partially 

 dehydrated product of natron. 



The analysis of the Barko chaniho is interesting. We have 

 3een from the analysis of the water of Barko that the dhand is 

 deficient in bicarbonate. In consequence, the chaniho of Barko 

 is largely normal carbonate, which must have crystallised as natron 

 from the dhand. 



The chaniho of Ganwarwaro was collected from the dried up 

 dhand, and represents the solid residue of the total dissolved salts. 

 The chaniho of Laiwari appears to have been collected from dried 

 up pools at the sides of the dhand. The dhand itself, from which 

 a specimen of water was taken, did not dry up at all. Consequently 

 the chaniho of this dhand represents an impure residual deposit. 



The chaniho of Bagarwaro is also an impure deposit. 



I have remarked in chapter II that there were from 8,000 to 9,000 

 maunds of chaniho on the southern shore of Lambro, which was of 

 " second grade " quality. That is to say, it is classed as second 

 grade by the local people. It is however impossible to see how 

 Lambro could produce anything except a largely sulphatic deposit, 

 considering the analysis of its water (see ante). The classing into 

 grades appears to be a purely physical classification based upon 

 the hardness and texture of the deposit, and freedom from solid 

 impurities, such as sand. No one seems to be able to distinguish 

 sulphate from carbonate of soda. 



The specimens analysed above are not average samples, but are 

 pieces picked at random from one of the chaniho stacks. Before 

 collection, they had been exposed to the ary air and sun's heat 

 for several months, and probably lost some of their volatile con- 

 stituents. 



It is perhaps worth while to recapitulate briefly the various 



views put forward regarding the formation of 



Formation of alka- alkalis in desert regions. It is generally recoo-- 



iino carbonates. , ° , J © 



insed that efflorescent salt characterises arid 

 areas of imperfect drainage where water rising to the surface by 

 capillary attraction is evaporated, leaving its burden of dissolved 

 salts as a crust on the surface of the soil. This crust is known in 

 North West India as reh, and in Sind as kalar. Land rendered 

 barren by the presence of such salts is termed usar land. Analyses 



