108 Chemical examination of the water of the 



It cannot be determined whether this water contains carbonic 

 acid, before the quantities of soda and lime are ascertained by anal- 

 ysis. It may be regarded as doubtful however, whether there is 

 any considerable excess of the acid generally present over and above 

 what is necessary to constitute the carbonate of soda a bi-carbonate, 

 and to render the carbonate of lime soluble. 



The sulphuric acid, which must be present in very small quantity, 

 is probably engaged with the soda, forming sulphate of soda ; inas- 

 much as this acid has a stronger affinity for soda than for lime, and 

 as the sulphate of soda is a more soluble salt than sulphate of lime. 



The chlorine may be regarded as divided between the calcium 

 and the sodium as is usual in mineral waters, forming the chloride of 

 calcium and the chloride of sodium. 



The silicic acid, though capable of solution in water to a small 

 extent, is probably maintained in solution by the carbonate of soda; 

 and when in a state of precipitation, appears to be partly free, and 

 in part in combination with oxide of iron, forming a silicate of iron. 



The crenic acid when in solution must be engaged by soda or lime ; 

 but that it also exists in the precipitate, appears from the odor of 

 the heated precipitate, in which condition it is probably united with 

 per-oxide of iron with which base it forms an insoluble compound. 



In what way the alumina is combined, or whether it be merely a 

 mechanical element, I shall not attempt to explain. 



It would seem most consistent with chemical theory to suppose, 

 that the iron was originally held in solution by the crenic and car- 

 bonic acids ; but that the access of the hydro-sulphuric acid had 

 completely decomposed these salts and given rise to the sulphuret 

 of iron. 



The appearance and disappearance of the precipitate in the water, 

 as mentioned at the connnencement of this article, and which is 

 chiefly silicic acid, may probably be explained by supposing the 

 quantity of carbonic acid subject to fluctuation ; when most abun- 

 dant, the bi-carbonate of soda may be formed, and the silicic acid 

 previously held in solution by it, deposited. When less abundant, 

 or when its escape is formed by a more elevated temperature in the 

 atmosphere as from frequent agitation, the carbonic acid may be ex- 

 pelled and the silicic, redissolved. Or, probably a hydro-sulphuret 

 of sodium may be formed, which occasions the precipitation of the 

 silicic acid, and on the decomposition of the hydro-sulphuret from a 

 higher temperature in the water or agitation, carbonate of soda may 

 combine anew with the silicic acid. 



