126 CHEMISTRY OF NATURAL WATERS. [IX. 



The analyses of the three given below may be taken as addi- 

 tional examples of this class. That of St. Ours is remarkable 

 for a large proportion of potassium-salts, about twenty-five per 

 cent of the alkalies, determined as chlorides, being chloride of 

 potassium.] 



Waters of Class IV. St. Ours. Joly. Nicolet. 



Chloride of sodium 0207 .0347 .3920 



potassium 0496 .0076 .0318 



Sulphate of potash 0081 



Carbonate of soda 1340 .1952 1.1353 



" lime 1740 .0710 undet. 



" magnesia 1287 .0278 " 



Iron-oxide, alumina, and phosphates . traces 



Silica .0161 .0110 



In 1,000 parts 5311 .3473 1.5591 



To the above may be joined, for comparison, the analysis 

 of the waters of a large river, the Ottawa, which drains a 

 region occupied chiefly by crystalline rocks, covered by ex- 

 tensive forests and marshes. The soluble matters which it 

 contains are therefore derived in part from the superficial de- 

 composition of these rocks, and in part from the decaying 

 vegetation. The water, which was taken at the head of the 

 St. Anne's rapids, on the 9th of March, 1854, before the melt- 

 ing of the winter's snows had begun, had a pale amber-yellow 

 hue, from dissolved organic matter, which gave a dark brown 

 color to the residue after evaporation. The weight of this 

 residue from 10,000 parts, dried at 300 F., was .6975, which 

 after ignition was reduced to .5340 parts. As seen in the 

 table below, one half of the solid matters in this water were 

 earthy carbonates, and more than one third was silica, so that 

 the whole amount of salts of alkaline bases was .088 (of which 

 nearly one half is carbonate of soda) ; while the St. Ours water, 

 which resembles that of the Ottawa in its alkaline salts, con- 

 tains in the same quantity 4.248, or more than forty-eight 

 times as much. The alkalies of the Ottawa water equalled 

 as chlorides .0900, of which .0293, or 32.5 per cent, were 

 chloride of potassium. The results of some observations on 



