292 THE CANADIAN NATURALIST. [Aug. 



fortieth there still remained in solution from 10.000 parts of water,. 

 •075 of silica and .028 of lime. Similar results were observed with 

 the alkaline saline waters of Varennes and Fitzroy ; and all of these 

 yielded, by further evaporation, precipitates containing silica and 

 lime, and in one instance magnesia. 



It is not however from alkaline waters like these, but from 

 neutral sea-water that the silicates of magnesia (and of lime), 

 which abound in stratified rocks, have been for the most part formed. 

 See farther on this point, § 41. 



§ 71. Organic Matters. In § 44 we have described some 

 of the reactions of the organic matter found in the Chambly water, 

 and it is to be remarked that small portions of a similar substance 

 were found in all alkaline waters of the third and fourth classes, 

 and caused them to become brownish when evaporated to a small 

 volume. This, it has been already suggested, may have a super- 

 ficial origin, the organic matters carried down by surface-waters 

 being kept in solution by the alkaline salts ; it is not however 

 impossible that this same menstruum may remove the organic 

 matters which abound in the pyroschists and other materials of 

 organie origin in the ancient rocks. Thus for example the copro- 

 lites of the Lower Silurian limestones contain so much animal 

 matter as to evolve an odor like burning horn when exposed to 

 heat. (Geology of Canada, 462). 



The Ottawa water (§ 45, No. 5), 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 addition 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 deposit opaque films of silicate of 

 ime. The finally dried residue was dark brown in color, and car- 

 bonized 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 

 orgjnic matter. 



No chemical examination was made of this matter held in solu- 

 tion by the concentrated water. From the late researches of 



