J836.] the Sdmar lake salt-works. 803 



B No. 1, from an old deep pit re-opened after 100 years. Examination by tests. 



Nitrate of silver, Copious precipitate. 



Nitrate of barytes, Very copious ditto. 



Oxalate of ammonia, No change. 



Prussiate of potash, Ditto ditto. 



Litmus paper, Ditto ditto. 



Turmeric ditto, Ditto ditto. 



A fair average sample was taken through the whole thickness of the lump. 

 100 grains exposed to a gentle heat lost 5.5 grains moisture. 

 100 grains treated with nitrate of barytes gave a precipitate, which after 

 having been well washed and dried, weighed 136 = 83 sulphate of soda. 



The filtered solution treated with nitrate of silver produced a precipitate of 

 chloride of silver, which after having been well washed and dried, weighed 22 

 grains = 10.4 muriate of soda. 



The composition of this sample is then as follows : 



Insoluble matter 1 



Moisture, 5 5 



Sulphate of soda, (and carbonate ?) ,... 83 



Muriate of soda, 10 4 



Loss, 1 



100 

 A No. 6. — The salt of which got mixed with scum while forming, appeared 

 very wet. 



When tested, this sample appeared to contain a considerable portion of alkali, 

 especially the reddish coloured part called scum in the list. 



100 grains dissolved, and the insoluble matter separated by the filter, washed 

 and dried, gave 2 grains. 



To the filtered solution was added acetic acid till the alkali became neutralized ; 

 after which it was treated with nitrate of barytes ; the sulphate of barytes was 

 precipitated, and having been well washed and dried, weighed 84 grains = 51 

 sulphate of soda. 



Nitrate of silver threw down a precipitate of chloride of silver that weighed 

 (after washing and drying) 30 grains = 14 muriate of soda. 



In order to ascertain the quantity of alkali in this sample, 100 grains were 

 dissolved in pure water, and treated (drop by drop) with sulphuric acid of speci- 

 fic gravity 1116 till the exact point of saturation was ascertained, by frequent- 

 ly testing with litmus paper. Towards the point of saturation a strong effer- 

 vescence took place. The solution was neutralized after 96 grains of the acid 

 test liquor had been used, which is equal to 10 per cent, of carbonate of soda. 



This sample being very wet, the moisture was ascertained in the usual way, 

 and amounted to 23 per cent. 



This sample, or rather what is called scum in the list, is composed of 



Sulphate of soda, 51 



Muriate of soda, 14 



Carbonate of soda, 10 



Insoluble matter, 2 



Moisture, 23 



100 

 5 m 2 



