IX.] CHEMISTEY OF NATURAL WATERS. 137 



in this paper is the very small amount of potassium in the 

 strongly saline muriated waters of the first three classes, which 

 we conceive to be more or less directly derived from the waters 

 of the ancient ocean. To this primeval sea, almost destitute 

 of potassium, the process of mineral decay has been for ages 

 adding potash-salts, and, despite the partial elimination of 

 these by vegetation ( 5), and by the formation of glauconite, 

 we find a notable proportion of potash in the waters of the 

 modern ocean. 



In the analyses of the saline waters here given lithia was 

 sought for in a few instances, and was detected in the waters 

 of Varennes. Most of these analyses were made before the 

 discovery of the new metals caesium and rubidium. 



54. SALTS OF CALCIUM AND MAGNESIUM. We have to 

 consider under this head the relations both of the chlorides 

 and the carbonates of these bases. The bitter saline waters 

 of the first class, although containing large quantities of chlo- 

 rides of calcium and magnesium, are, as we have seen, gener- 

 ally destitute of earthy carbonates. These latter, however, are 

 found in small quantities in the alkaline waters of the fourth 

 class, and in somewhat larger amounts in those intermediate 

 waters which form Classes II. and III., and are apparently 

 formed by admixtures of the two classes previously mentioned. 

 Besides the carbonates of lime and magnesia which the waters 

 of the fourth class hold in solution, the carbonate of soda 

 which they contain gives rise, by its reaction with the chlo- 

 rides of calcium and magnesium, to additional quantities of 

 the carbonates of these bases. In the bitter saline waters of 

 Kingston (described in the original paper) a large amount 

 of chloride of calcium is associated with earthy carbonates, 

 and these waters thus offer a passage from the first to the sec- 

 ond class. 



In most of the waters of the second class, as will be seen 

 from the table in 42, there appears but a small amount of 

 chloride of calcium ; and even this depends upon the manner 

 in which the analysis has been conducted. We may suppose 

 in the recent water such a partition of bases between the chlo- 



