IX.] CHEMISTRY OF NATURAL WATERS. 153 



The Ottawa water ( 46), when boiled to one tenth, deposits 

 a precipitate in small bright brown iridescent scales. This was 

 found to contain silica, carbonate of lime, and a small portion 

 of an organic substance which was dissolved in dilute potash 

 ley. The brown solution thus obtained was not disturbed by 

 acetic acid and acetate of copper, but by the subsequent ad- 

 dition of carbonate of ammonia yielded a white precipitate. 

 The concentrated water retained a large proportion of organic 

 matter, and when reduced to a small bulk was dark brown, 

 alkaline to turmeric-paper, and continued by evaporation to de- 

 posit opaque films of silicate of lime. The finally dried residue 

 was dark brown in color, and carbonized by heat, burning like 

 tinder and diffusing an agreeable odor. The residue of 10,000 

 parts dried at 300 F. weighed .6974, and lost by gentle 

 ignition .1635, consisting partly of organic matter. No chemi- 

 cal examination was made of this matter held in solution by 

 the concentrated water. From the late researches of Peligot, 

 however, it appears that the organic matter precipitated by 

 nitrate of lead from the water of the Seine has nearly the com- 

 position of the apocrenic acid of Berzelius. It gave, on analy- 

 sis, carbon 53.1, hydrogen 2.7, nitrogen 2.4, oxygen 41.8, and 

 is evidently related to the soluble form of vegetable huinus. 

 (Comptes Rendus, April 25, 1864.) When exposed to heat 

 this substance evolved ammonia, with the odor of burning 

 wool, while the organic matter from the Ottawa water, on the 

 contrary, gave an odor like burning turf. 



GEOLOGICAL POSITIONS OF THE PRECEDING WATERS. 



72. The palaeozoic area from which the above-described 

 waters are derived includes the basin of the St. Lawrence from 

 Lake Erie to near Quebec, with its extensions in the valleys of 

 the Lower Ottawa and Lake Champlain. Over the greater part 

 of this champaign region the strata are nearly horizontal, but 

 towards its eastern part there are various minor folds and un- 

 dulations. It is in this disturbed region that by far the greater 

 7* 



