55^ Transactions of the Canadian Institute. [Vol. VII. 



partially, by regions in which pre-Cambrian formations occur, or are 

 the only apparent rocks, the potassium predominates over the sodium. 

 For example, in the water from Reindeer Lake, which is situated 400 

 miles directly north of Lake Winnipeg, Professor Adams found the 

 potassium to exceed very greatly the sodium. In the water from the 

 Churchill River, as well as in the water from the Saskatchewan River 

 above the junction of the Big Stone River, the potassium is much richer 

 than the sodium.* These rivers drain rocky areas chiefly of the pre- 

 Cambrian type. Rocks of the primitive kind, therefore, contrary to the 

 prevailing opinion,j- supply to the water which comes in contact with 

 them more potassium than sodium. 



Even in the case of Lake Superior which draws its supply not only 

 from the primitive rock region on its northern side, but also from the 

 areas covered with soils of alluvial and drift origin on the south, the 

 potassium is about equivalent to the sodium. In the lakes of the 

 Bavarian Highlands, Rachel See, Wlirm See and Ronig See, the 

 potassium is twice in amount that of the sodium. In Lake Zurich the 

 potassium exceeds the .sodium. In Lake Geneva, in Pyrenean and 

 Vosgean Lakes and in those of Russia, Armenia and Central Asia the 

 potassium is approximately two-thirds of the sodium. It is probable 

 that if proper methods for estimating potassium had been current in his 

 day, C. Schmidt would have found for the lakes of Russia, Armenia and 

 Central Asia a higher potassium value than he obtained, for the 

 methods then in vogue for the determination of the element in the 

 presence of sodium were very faulty and gave very low results. It is 

 probable also that this may explain the low value found by Sterry Hunt 

 for the potassium of the Ottawa River, whose waters, as well known, are 

 derived largely from Archaean regions. 



The Tables A and B show further that, in nearly all cases, the 

 calcium is very abundant. In the Nile only, amongst the rivers, is it 

 less than the sodium, while it very greatly exceeds it in the rest. In the 

 lakes it is very abundant relatively, with the exception of the Rachel See 

 and Lake Onega. In the Bavarian lakes, Lake Geneva, Lake Zurich, 

 and some others, it is exceedingly abundant relatively. 



The magnesium is always less than the calcium, and the relative 

 difference is sometimes very great. It may fall below the sodium, but, 

 as a rule, it is greater in amount. 



These proportions, one can readily understand, must have been 



* F. D. Adams Geo. and Nat. Hist. Survey ot Canada, 1880-2, p. 6, 4. 



t This opinion is based largely on the fact that the potash feldspars are difficult to decompose while 

 the soda feldspars readily undergo decomposition. 



