HOW THE WATEKS OF THE OCEAN BECAME SALT. 49 



13 We must, I think, concur with Dr. Hunt that from some 

 cause or other, chlorine largely abonnded in the waters of 

 the primasval ocean, as by far the greater proportion of the 

 salts are chlorides, and chlorine is but very slightly repre- 

 sented in river waters at the present day. 



14 In contrast to the above, which may be called '' the 

 chemical theory," we may now consider that which may be 

 called "the geological theory,'' though it very much depends 

 upon certain chemical processes. 



15 If we compare the analyses of waters brought down by 

 rivers into the ocean at various parts of the globe we shall 

 find that the matters in solution are very much the same as 

 those which we find dissolved in oceanic waters ; the pro- 

 portions are doubtless immensely different, but the ingre- 

 dients are essentially similar. Now, what are the dissolved 

 ingredients of river Avaters ? They are calcium, magnesium, 

 sodium, potassium, a little iron, silica, alumina, and other 

 matters, in combination Avith carbon-dioxide (carbonic acid 

 gas), sulphuric acid, hydrochloric acid. Of these the carbon- 

 ates of lime and magnesia are the most abundant, but 

 chlorides of sodium and magnesium are almost always 

 present even in waters where there can be no suspicion that 

 they have been introduced by any artificial means. These 

 constituents are also found in even larger proportions in the 

 Avaters of natural springs ; and in such chlorine occurs, some- 

 times in considerable cpiantity, in combination Avith sodium, 

 magnesium, and jDotassium. Spring water coming as it does 

 directly from the strata, or from rocks of A^arious kinds, is 



dated ?) certain furnace slags or volcanic glasses. The atmosphere charged 

 with acid gases which surrounded this primitive rock must have been of 

 great density. Under the pressure of a high barometric column con- 

 densation could take place at a temperature much above the 2)resent 

 boiling point of water, and the depressed portions of the half-cooled crust 

 would be flooded with a highly heated solution of hydrochloric and 

 sulphuric acids, wdiose action in decomposing the silicates can easily be 

 understood. The formation of the chlorides and suli)hates of the various 

 bases and the separation of silica would go on mitil the afliuities of the 

 acids were satisfied, and there would be a separation of silica taking the 

 form of quartz, and the production of sea-water holding in solution, 

 besides the chloiides and the sulphates of sodium, calcium, and mag- 

 nesium, salts of aluminium and other metallic bases. The atmosi)here 

 being thus deprived of its volatile chlorme and sul[)hur compounds, would 

 gradually approximate to that of our own time, but would differ in the 

 greater amount of caibonic acid gas." Chemical wid Geological Essays, 

 p. 40 (1875). 



