1 50 Analysis of the water of Rio Vinagre. 



zIhc filings, produces hydrogen gas. ' The reagents indicate sulphu- 

 ric and hydrochloric (muriatic) acids, with hme and alumina, and 

 traces of iron and magnesia. 



Quantitative results of an analysis at Purace, April, 1831. — 422 

 grammes* of the water gave, with nitrate of silver, 2.01 grs. of 

 chloride of silver, equivalent to 0.384 gr. hydrochloric acid. 422 

 grammes, treated by chloride of barium, gave 1.35 gr. sulphate 

 barytes, containing 0.464 gr. sulphuric acid. 



422 grammes, concentrated by evaporation, were treated with 

 caustic ammonia, and gave a precipitate of alumina weighing 0.17 gr. 

 which contained traces of iron and magnesia ; from the fluid, depri- 

 ved of the alumina, oxalate of ammonia precipitated lime ; the oxa- 

 late of lime, changed into a carbonate, weighed 0.10 gr., containing 

 0.056 gr. lime ; the liquid was now evaporated and the ammoniacal 

 salts driven off, and there was a residuum of alkaline sails of soda ; 

 these were changed to a sulphate ; the sulphate of soda weighed 

 0.13 gr., but in dissolving in Water lost 0.01 gr. of silex, and was. 

 thus reduced to 0.12 gr., representing 0.05 gr. of soda. 



The water of the Rio Vinagre containsj according to this analysis. 

 Sulphuric acid, - - - 0.00110 



Hydrochloric acid, - - - ' .00091 



Alumina, - - - - .00040 . . 



Lime, - _ _ - .00013 



Soda, - - - - - .00012 



Silica, - - - - .00023 



Oxides of iron and magnesia, traces. 

 Or, supposing the alumina and lime to be combined with the sul- 

 phuric acid, the composition of the water may be given thus : 

 Sulphate of alumina, - - - 0.00131 



Sulphate of lime, - - - .00031 



Chloride of sodium, - . - - .00022 



Silica, " - - - - .00023 



Hydrochloric acid, - - - .00081 



But it is not only possible, but even probable, that the "acidity of 

 the water of the Pasambio is owing more to the sulphuric than to 

 the hydrochloric acid, since free hydrochloric acid could not be 

 found in the products of the volcano of Purace, and I have discov- 

 ered in the crater of the volcano of Pasto a great quantity of an 

 acid sulphate of alumina," which communfcates to the water an acid 

 and astringent taste. 



* The gramme is about 15^ grs. Troy. 



