1865.] CHEMISTRY OF NATURAL WATERS. 281 



excess of carbonic acid. The power of alkaline chlorids and of 

 chlorid of calcium to prevent the precipitation of chlorid of 

 calcium by carbonate of soda has already been observed by Storer, 

 (Dictionary of Solubilities, p. 110). I have found that the precipi- 

 tate produced by the admixture of solutions of these two salts is 

 readily dissolved, when recent, by a solution of chlorid of calcium, 

 or of sulphate of magnesia ; and thus liquids may be prepared 

 holding at the same time from 1.0 to 1.2 grams of neutral carbonate 

 of lime, and 1.00 of neutral carbonate of magnesia, in presence of 

 sulphate of magnesia. These solutions of carbonate of lime, which 

 are strongly alkaline, may be kept for twelve hours or more without 

 perceptible change at ordinary temperatures, but after a time 

 deposit crystals of hydrated carbonate of lime. The addition 

 of alcohol immediately throws down the whole of the carbonate of 

 lime in an amorphous condition. 



The carbonate of magnesia is still more soluble than the carbo- 

 nate of lime under similar conditions, and it is possible to obtain 

 5.0 grams of neutral carbonate of magnesia dissolved in a litre of 

 water holding seven per cent of hydrated sulphate of magnesia, 

 without any carbonic acid. These solutions, which are strongly 

 alkaline to test-papers, yield a precipitate by heat, which re-dis- 

 solves on cooling. 



It is evident that the mingling of saline and alkaline waters may 

 give rise to solutions like those just described, and thus explain 

 apparent anomalies in composition like that of the Kingston water. 

 See also in this connection the observations of Bineau, and my 

 own on the properties of solutions of sesqui-carbonate of magnesia. 

 (Silliman's Journal [2] xxvii. 173.) 



§ 57. Salts of Barium and Strontiu3I. — As will be seen from 

 the preceding tables, the salts of these two bases are found in very 

 many of the saline and alkaline waters of Canada. Their carbon- 

 ates probably sustain to the magnesian chlorid a similar relation with 

 that of calcium, and hence these bases appear in some of the analyses 

 partly as carbonates, and partly as chlorids of barium and strontium. 

 The precipitate formed in the concentrated and acidulated water 

 by dilute sulphuric acid was, whenever submitted to analysis, 

 found to contain both barium and strontium. For the separation of 

 these the mixed sulphates were first converted into chlorids ; the 

 barium was then thrown down as silico-fluorid, and the strontium 

 subsequently precipitated by a solution of gypsum. 



The insolubility of its sulphate must have excluded baryta from 



