1865.] CHEMISTRY OF NATURAL WATERS. 183 



1000 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 predomi- 

 nates, but few have yet been observed in this country. A remark- 

 able example of this kind from Hamilton, C. W., was examined by 

 Prof. 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 1000 parts, 



Chlorid of sodium , « -5098 



Sulphate of soda 1-6985 



" lime 1-1246 



" magnesia 4-7799 



8-1128 

 The rocks exposed at Hamilton include the Medina sandstone 

 and the Niagara limestone, with the intermediate Clinton 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, p. 460.) 

 According to Emmons, the post-tertiary clays near Crown 

 Point, on the western shore of Lake Champlain, are during dry 

 weather covered with efflorescences of sulphate of magnesia, which 

 impregnates several springs in the vicinity. The water of one of 

 these, according to Emmons, had a specific gravity of 1014.0, and 

 contained in 1000 parts, 18.78 of saline matter, which was chiefly 

 sulphate of magnesia, with some sulphate of lime (cited by Beck, 

 Mineralogy of New York, p. 252). The strata underlying the clays 

 of this region belong according to the State geological map, to the 

 Potsdam, Calciferous, and Trenton formations ; but the source of 

 the magnesian salt is, not improbably, to be found in the clays 

 themselves. 



In the third and concluding part of this paper it is proposed to 

 notice briefly some of the more important points in the chemistry 

 of the various waters which have been here described, and to 

 inquire into their geological relations. — SilUman's Journal. 



