^42 Dr. Marcet on an Aluminous Chalybeate Spring 



7. Since therefore, the whole of the murlat of soda, as was before 

 computed (§ XIII. 2), amounted only to 4 grains in a pint, the 

 quantity of crystallized sulphat of soda contained in each pint of the 

 water will be 16 grains. 



§ XV. Comparison of the quantities of Acid actually obtained 

 from the water by precipitation^ with the quantities inferred from 

 the precipitation of the bases. 



1 . It appears evident, from all that precedes, that the only acids 

 contained in the water are the sulphuric and muriatic. The whole 

 of the muriatic acid having been shewn to exist in the form of mu- 

 riat of soda, nothing further remains to be said on this head. But 

 it will be curious to examine how far the total amount of sulphuric 

 acid, obtained from a portion of the water, would coincide with 

 that which might be inferred from the quantities of bases with which 

 it was combined. This inquiry will give rise to the statement of 

 certain results respecting the proportions of acid and base in some of 

 the salts concerned, and the precipitates obtained from their decom- 

 position, which, from their general import in chemical analysis, 

 appear to deserye some attention. 



2. It was ascertained by a direct experiment (§ XIII. 1), that the 

 whole of the sulphuric acid contained in a pint of the water, formed, 

 when precipitated by a barytic salt, a quantity of sulphat of barytes, 

 which, after being ignited, weighed 74 grains. 



I shall now recapitulate the several sulphats discovered in the 

 water, and from the quantities of each, compute the quantities of 

 barytic sulphat which would result from their decomposition. 



