288 THE CANADIAN NATURALIST. [Aug. 



the carbonic acid present; while the falling off in the amount of 

 carbonates in 1865 is such that only .191 of carbonic acid, or just 

 about one-third of the carbonic acid present, is required for the 

 neutral carbonate. Nor is this change due entirely to a less 

 amount of carbonate of soda ; the carbonates of lime and magnesia 

 in 1847 required .246, and in 1865 only .153 of carbonic acid 

 The changed conditions which we here meet with may be explained 

 by supposing that the carbonated bases are due to the mingling in 

 different proportions of neutral carbonate of soda (generated by the 

 reaction indicated in § 13,) with an earthy saline water holding a 

 constant amount of free carbonic acid ; which, in some cases, is 

 more tban is required to form bicarbonates, but in others, as we 

 have seen above, presents a deficiency. 



§ 66. If we admit, as I have already assumed, that the waters 

 of the second and third classes have been generated by the ming- 

 ling of solutions of carbonate of soda with waters of the first class, 

 it can readily be shown that these solutions contained chiefly or 

 exclusively the neutral carbonate. If we add a solution of bicarbonate 

 of soda to earthy saline waters of the first class it is 

 easy to obtain solutions of holding twenty grams or more of 

 bicarbonate of magnesia to the litre ; while in none of the 

 natural waters of the second class do our analyses show the 

 existence of much over one gram to the litre. Again, if we sup- 

 pose any considerable amount of chlorid of calcium to be decom- 

 posed by bicarbonate of soda, the separation of the lime in the form 

 of neutral carbonate, and the liberation of the second equivalent 

 of carbonic acid, would yield waters holding an excess of carbonic 

 acid above that required to form the bicarbonates of the solution. 

 From the absence of such an excess, as appears in the case of the 

 waters of Caledonia, Yarennes, St. Leon and Caxton, and from the 

 small amount of bicarbonate of magnesia in these waters, it may be 

 concluded that the alkaline salt whose addition has changed their 

 character was the neutral carbonate of soda. 



§ 67. Examples are not wanting of waters in which, as in those 

 of Caledonia in 1847, the carbonic acid is insufficient to form 

 bicarbonates, or even neutral carbonates, with the bases uncombined 

 with sulphuric acid or chlorine. Thus, according to Pagenstecher 

 and Muller, the spring and well-waters of Berne do not contain 

 sufficient carbonic acid for the lime present, a part of which they 

 suppose to be held in solution as a silicate, See Bischof, Chem. 

 Geology, i. 5 ; who remarks that Lowig seems to have observed the 



