

cyftwo hot Mineral Springs in India. 97 



solution was highly alkaline from the presence of carbonate of 

 soda, and had a pale yellow colour derived from the organic 

 matter. On digesting the solution for a few minutes with car- 

 bonate of ammonia, so as to saturate the soda with carbonic acid, 

 a gelatinous precipitate subsided, which had all the characters 

 of pure silica. The alkaline solution, after being acidulated 

 with nitric acid, yielded white precipitates with the nitrates of 

 silver and baryta, and hence must have contained muriatic and 

 sulphuric acid. I could not detect any nitric or hydriodic 

 acid. The portion which was insoluble in water, equally resisted 

 the action of muriatic acid, and proved on examination to be 

 siliceous earth. Traces of iron and lime were separated from 

 it by the acid. 



The properties just enumerated demonstrate, that the so- 

 lid contents of the hot spring of Pinnarkoon consist of silica, 

 soda, chloride of sodium, sulphuric and carbonic acids, a small 

 quantity of animal and vegetable matter, water, and traces of 

 lime and iron. The relative proportion of these ingredients 

 was ascertained in the following manner. 



10.172 grains of the solid matter heated to redness, lost 

 2.1 12 grains or 20.76 per cent. The residue effervesced slightly 

 with dilute sulphuric acid, and the loss in carbonic acid amount- 

 ed to 2.57 per cent. Before exposure to heat 22.09 grains, 

 when treated by dilute sulphuric acid, lost 1.72 grains, or 7.786 

 per cent, of carbonic acid. Consequently it follows, that the 

 total loss in water, and a little organic matter, occasioned by 

 heat, amounts to 15.544 per cent. The quantity of carbonic 

 acid was ascertained by the method described to the society 

 on a former occasion, and which admits of minute accuracy. 



To discover the proportion of soda, 8.525 grains of the so- 

 lid contents of the spring were dissolved in dilute sulphuric 

 acid, the solution evaporated to dryness, and the residue ex- 

 posed to a red heat. The sulphate of soda, separated from a 

 trace of iron and siliceous matter, amounted to 6.72 grains ; 

 equivalent to 2.987 grains, or 35.05 per cent, of pure soda. 



The quantity of silica was ascertained by acting upon the 

 saline mass with muriatic acid, evaporating to dryness, and 

 after digesting the silica in acidulated water, collecting it on 

 a filter, and exposing it to a red heat. The pure siliceous 



VOL. IX. NO. I. JULY 1828. c 



