Page:Popular Science Monthly Volume 4.djvu/543

Rh properly belongs; the waters above are to be separated by the "firmament" from the seas beneath. Next, we may observe chemical reactions. The condensed steam, in falling through the lower zones, would dissolve the sulphuric and hydrochloric gases, and convert the rain into powerful acids. When these fall upon the slaggy crust, the excrescences will not only be removed, to be deposited as sediment in the hollows, but a large percentage of the surface will enter into solution, giving rise, not to an acid ocean, but one containing sulphates and chlorides. The more soluble silicates would be converted into chlorides, leaving upon the slaggy floor piles of silica. The sulphates may have been largely of the heavier metals, not excluding the others.



Prof. Wurtz thinks the first ocean would be characterized by the predominance of sulphates. Granting this, we can understand the conversion of the sulphates into sulphurets in subsequent periods, as well as into gypsum. Aqueous deposits of sulphurets of copper, iron, lead, antimony, etc., are common in Eozoic and Paleozoic strata. The action of carbonic acid must not be overlooked. The liquid acids may have disintegrated the silicates of the alkalies and alkaline earths; but the compounds of silica, with alumina and iron, are not so easily decomposed. As soon as the carbonic acid could act upon feldspar compounds, we should have the potash and soda dissolved out as