1865.] 



CHEMISTRY OF NATURAL WATERS. 



175 



causes it to assume a bright brown color when reduced by evapo- 

 ration. Acetic acid gave no precipitate with the concentrated 

 and filtered water ; but the subsequent addition of acetate of cop- 

 per yielded a brown precipitate of what was regarded as apocrenate 

 of copper. The organic matter of this and of many other mineral 

 springs has probably a superficial origin. The carbonic acid was 

 determined in the third analysis, and was equal in two trials to 

 .903 and .905. The neutral carbonates in this water require .452 

 parts of carbonic acid. 



§ 45. In the following table are given the analyses of several 

 other waters which belong like the last to the fourth class. 



TABLE IV.— WATERS OF THE FOURTH CLASS. 



1. This spring was met with some years since in constructing 

 a lock on the Richelieu River at St. Ours, and was enclosed 

 in such a way that it is only accessible through a pump ; so 

 that it is impossible to determine the amount of water furnished 

 by the spring, or its freedom from admixture. The water was 

 obtained in November 1852, and is remarkable for the large pro- 

 portion of potassium salts. 1000 parts of the water gave of alkalies 

 determined as chlorids, 0.2250; of which 0.0565 parts, or 25.11 

 per cent, were chlorid of potassium. Another trial gave 24.52 

 per cent, ; while a portion of the water taken from the spring three 



