IX.] CHEMISTRY OF NATURAL WATERS. 147 



65. CARBONATES. In examining in 1847 the alkaline- 

 saline waters of Caledonia, it was found that these contained a 

 quantity of carbonic acid insufficient to form bicarbonates 

 with the carbonated bases present. It was partly with this 

 fact in view that, after an interval of more than seventeen 

 years, I undertook the new analyses of these waters, which in 

 47 are given side by side with the earlier results. In these 

 later analyses, as there remarked, a slight excess of carbonic 

 acid was met with. In the interval the springs had under- 

 gone changes in composition, and while the third one still 

 retained in a slight degree its alkaline character, the other two 

 had become waters of the second class, holding, instead of 

 carbonate and sulphate of soda, chloride of magnesium, and 

 baryta salts. The amount of carbonic acid had, however, 

 undergone but little change ; and as will be seen by compar- 

 ing the figures below with those in the table in 47, the slight 

 diminution in the first and third corresponds very closely with 

 the falling off in the amount of solid matters between 1847 and 

 1865 ; while, on the contrary, the augmentation in the amount 

 of carbonic acid in the second is accompanied with a corre- 

 sponding increase in the amount of fixed matters present. 



CARBONIC ACID IN ONE LITRE OF THE CALEDONIA WATERS. 



1847. 1865. 



Gas Spring 705 grammes. .671 grammes. 



Saline Spring 648 " .664 " 



Sulphur Spring 590 " .573 " 



While the amounts of fixed matters and of carbonic acid in 

 the several waters have undergone but little change, we find, 

 however, that there has been a great diminution in the pro- 

 portion of carbonated bases. Thus in the Gas Spring in 

 1847 the carbonic acid required for the neutral carbonates 

 found in the analysis was .356, while for the same water in 

 1865 only .278 of carbonic acid was required. In the Sul- 

 phur Spring, in like manner, the neutral carbonates required 

 .449, or more than three fourths of the carbonic acid present ; 

 while the falling off in the amount of carbonates in 1865 is 



