134 CHEMISTRY OF NATURAL WATERS. [IX. 



pkur spring which issues from a mound of calcareous tufa in 

 Brant, in Ontario, overlying the Corniferous limestone, is dis- 

 tinguished by the absence of any trace of chlorides ; in which 

 respect it resembles the acid waters of the fifth class from the 

 adjacent region. A partial analysis of a portion of it collected 

 in 1861 gave, for 1,000 parts, sulphate of lime 1.240, sulphate 

 of magnesia .207, and carbonate of lime .198. From a slight 

 excess in the amount of sulphuric acid, it is probable that a 

 little sulphate of soda was also present. 



Of waters of this class, in which sulphate of magnesia pre- 

 dominates, but few have yet been observed in this country. 

 A remarkable example of this kind, from Hamilton, Ontario, 

 was examined by Professor Croft, of Toronto, and described 

 by him in the Canadian Journal for 1853 (page 153). It 

 had a specific gravity of 1006.4, and gave, for l',000 parts, 



Chloride of sodium '. .5098 



Sulphate of soda 1.6985 



lime . . . . . . 1:1246 



" magnesia 4.7799 



8.1128 



The rocks exposed at Hamilton include the Medina sand- 

 stone and the Niagara limestone, with the intermediate Clin- 

 ton group. Along the outcrop of the latter, crystalline crusts 

 of nearly pure sulphate of magnesia are observed to form in 

 many localities, during the dry season of the year. (Geology 

 of Canada, 460.) 



