282 THE CANADIAN NATURALIST. [Aug. 



the waters of the primeval sea, and when set free, as we may- 

 suppose by the decomposition of its silicated compounds existing 

 in the primitive crust, (§81) its soluble bicarbonate carried 

 down to the sea would there be precipitated by the sulphates 

 present. A similar process must still go on with all the dissolved 

 barytic salts which find their way to the ocean. 



The sulphate of baryta thus accumulated in sedimentary 

 strata, may be partially decomposed by infiltrating solutions of 

 alkaline carbonates, and thus be rendered capable of being sub- 

 sequently dissolved as carbonate ; but the most probable mode of 

 its solution, is, we conceive, through its previous reduction by 

 organic matters to the form of a soluble sulphuret (§ 10), ready to 

 be converted into carbonate or chlorid of barium. In this way 

 we may explain the frequent occurrence of baryta salts in the 

 saline waters of the first three classes, and the consequent absence 

 of sulphates, which will be further considered in § 61. From 

 the similarity of its chemical re-actions, the preceding remarks 

 apply to strontia as well as baryta. 



§ 58. Iron, Manganese, Alumina and Phosphates. — None 

 of the waters of the four classes here described contain any notable 

 quantity of iron, yet this element is never wanting in those waters 

 which contain earthy carbonates. Whenever a portion of one of 

 these waters, or better the earthy precipitate separated from it by 

 boiling, is evaporated to dryness with an excess of hydrochloric 

 acid, the residue treated with acidulated water yields a portion of 

 silica, and the solution will then be found to yield with ammonia 

 a precipitate. This, which is partially soluble in caustic alkalies, 

 is often colorless, and will be found to consist of alumina and 

 peroxyd of iron, with phosphoric acid and a trace of manganese, 

 which latter metal is seldom or never absent. The small quantity 

 of alumina which these waters contain appears not to be derived 

 from suspended argillaceous matters, but to be held in a state of 

 solution. 



The phosphates are generally present only in very small 

 quantities in these waters, for the reason pointed out in § 5. The 

 largest amount which I have met with was in an alkaline water 

 from Fitzroy (§ 43, No. 4); where it is equal to -0124 of tribasic 

 phosphate of soda in 1000 parts of water. 



§ 59. Bromids and Iodids. — The chlorids in these ancient 

 mineral waters are always accompanied by bromids and iodids, 

 but the proportion of the bromids to the chlorids appears to be 



