Geological Survey of Canada. 98 



The dried residue from the evaporation of this water is of a deep brown 

 color, when ignited, the organic matter which it contains burns like 

 tinder, diffusing an agreable vegetable odour, and leaving a little carbon. 

 The water was not examined for nitrates ; but the absence of any defla- 

 gration during the ignition of the residue, showed that if present they 

 were in very small amount. The season moreover at which the water 

 was collected (being at the end of a winter of four months of unremit- 

 ting frost), would not be favorable to the formation of nitrates 



The following numbers are deduced from the means of two or more 

 concordant determinations made upon quantities of two and four litres 

 of the Ottawa, and calculated for ten litres or 10-000 grammes. 



Carbonate of lime, 0-2480 grms. 



" " magnesia, -0696 



Chlorine, -00^6 



Sulphuric acid, '0161 



Silica, -2060 



Chlorid of sodium, -0607 



" " potassium, -0293 



Residue dried at 300° F., -Q2*lb 



. " ignited, -5340 



The amounts of silica remaining dissolved in the water evaporated to 

 one-twentieth and one-thirtieth, were found to be 0-019 and 0-020 for 

 four litres, giving for the ten litres a mean of 0-046 grammes of silica 

 thus retained in solution. The amount of lime remaining dissolved in 

 this quantity of the water thus evaporated, was equal to 0-023 of carbo- 

 nate of lime. 



The chlorine and sulphuric acid present in this water are sufficient to 

 neutralize only about one-half of the alkaline bases present. The remain- 

 ing portion may be regarded as existing in combination either with silica 

 or with the organic acids present ; and it is probably in a similar state of 

 combination that a portion of the lime remains dissolved in the evapo- 

 rated water. 



In the following table the lime and the excess of alkalies are however 

 represented as carbonates, and we have for 10-000 parts, 



Carbonate of lime, 0-2480 



" " magnesia, -0696 



Silica, '. -2060 



Chlorid of potassium, -0160 



Sulphate of potash, , -0122 



" ''soda, -0188 



Carbonate of soda, -0410 



Alumina and oxyd of iron, (traces) 



Manganese and phosphoric acid, " 



0-6116 

 The water of the St. Lawrence was collected on the 30th of March, on 

 the south side of the Pointe des Cascades (Vaudreuil). Tbe rapid cur- 

 rent had here left an opening in the ice, from which the water was taken 



