COMPOSITION OF RIA^ER WATERS 



[6i 



ter does not exist in nature. That of lakes and rivers suitable for 

 drinking purposes (by man) always contains in the neighborhood of 

 O.I permille of mineral matter, especially calcium carbonate. Wa- 

 ter above 0.15 or 0.2 permille cannot be considered potable, espe- 

 cially if the percentage of sodium chloride is high. (Bibliography 

 V-44.) The average composition of fresh-water lakes is shown by 

 the following analyses of the w^aters of Lake Baikal, the American 

 Great Lakes and Lake Champlain. ( Clarke-4 : 61, 81.) 



Table of Average Composition of Lake Waters. 



III. Composition of River Water. 



The composition of river water varies in accordance with the 

 character of the rock, over or in which the river flows, and the na- 

 ture of the supply. Though different rivers show varying amounts 

 in the totality of solids, this is never very high, while at the same 

 time the relative preponderance of the salts does not change greatly. 

 The following table gives the totality of solids in a number of rivers, 

 together with the predominant element or compounds in each. 

 (Russell-30, Table A; Clarke-4 :(5o-6'i'. ) 



