IX.] CHEMISTRY OF NATURAL WATERS. 141 



waters. See also in this connection the observations of Bineau, 

 and my own on the properties of solutions of sesqui-carbonate 

 of magnesia. (Amer. Jour, Science (2), XXVII. 173.) 



57. SALTS OF BARIUM AND STRONTIUM. The salts of 

 these two bases are found in very many of the saline and 

 alkaline waters of Canada. Their carbonates probably sustain 

 to the magnesian chloride a similar relation with that of cal- 

 cium, and hence these bases appear in some of the analyses 

 partly as carbonates, and partly as chlorides of barium and 

 strontium. The precipitate formed in the concentrated and 

 acidulated water by dilute sulphuric acid was, whenever sub- 

 mitted to analysis, found to contain both barium and stron- 

 tium. For the separation of these, the mixed sulphates were 

 first converted into chlorides ; the barium was then thrown 

 down as silico-fluoride, and the strontium subsequently pre- 

 cipitated by a solution of gypsum. 



The insolubility of its sulphate must have excluded baryta 

 from the waters of the primeval sea, and when set free, as we 

 may suppose, by the decomposition of its silicated compounds 

 existing in the primitive crust ( 12), its soluble bicarbonate 

 carried down to the sea would there be precipitated by the 

 sulphates present. A similar process must still go on with 

 all the dissolved barytic salts which find their way to the 

 ocean. 



The sulphate of baryta thus accumulated in sedimentary 

 strata may be partially decomposed by infiltrating solutions 

 of alkaline carbonates, and thus be rendered capable of being 

 subsequently dissolved as carbonate; but the most probable 

 mode of its solution is, we conceive, through its previous re- 

 duction by organic matters to the form of a soluble sulphuret 

 ( 10), ready to be converted into carbonate or chloride of 

 barium. In this way we may explain the frequent occurrence 

 of baryta-salts in the saline waters of the first three classes, 

 and the consequent absence of sulphates, which will be further 

 considered in 61. From the similarity of its chemical re- 

 actions, the preceding remarks apply to strontia as well as 

 baryta. 



