The Chemistry of the Primeval Earth. 363 



these acids. Indeed, the action would probably be very energetic, 

 and would go on until the whole of the affinity of the acid 

 was saturated at the expense of the lime, magnesia, and soda, and 

 other metallic bases which form a portion of this crystalline scoria- 

 ceous mass — ^this primary slaggy surface. The silica separated at 

 this high temperature, if we may judge from the investigations of 

 chemists, would take the crystalline form, and you would thus have, 

 naturally, great deposits at the surface of the earth of silica, pro- 

 bably in the form of crystalline or granular quartz ; and you would 

 thus have a separation of quartz on the one hand, and on the other 

 hand you would have the waters of the primeval ocean intensely 

 impregnated with chlorides and sulphates of all the bases which 

 were at first combined with this quartz — with this siliceous matter. 

 This process is a submarine one ; that is to say, it would take place 

 only in the depressions of the earth's surface where these waters 

 accumulated. And it would be a very rapid process. The action 

 would very soon be exhausted, because the affinities of these acids — 

 hydrochloric acid, and sulphurous acid, and perhaps sulphuric acid 

 — formed at that temperature would soon be satisfied. Then comes 

 another and a slower process, which would be effected upon the 

 exposed portions of the crust by the carbonic acid in the atmosphere, 

 combined with the moisture there present, — a process of slow decay 

 and transformation of all these silicates which are thus exposed; 

 and that is a process similar to that which is now going on at the 

 surface of the earth by which our hardest granites and gniesses, 

 hard felspathic and pyroxenic rocks, are broken down and converted 

 into clay — a process which even makes the granites of Cornwall 

 crumble into Kaolin. In the elimination from these felspathic rocks 

 of the alkali which they contain — the lime, magnesia, and soda — 

 there would be a separation of silica and alumina in the form of 

 clay, which remains insoluble at the surface of the earth, and the 

 formation of carbonates of soda, of lime, and of magnesia, these 

 carbonates being formed at the expense of the carbonic acid in the 

 atmosphere, which is absorbed by these bases at the moment they 

 are liberated ; — and these, through the condensing waters or rains 

 which are falling upon the surfaces exposed to subaerial action, are 

 carried down into the sea, where their first act would be to pre- 

 cipitate alumiuous matters, — to precipitate at that high temperature 

 all the denser metals, and, finally, to give us a sea which would 

 consist only of lime, magnesia and soda. 



Now, that process is still going on — has been continued down to 

 our present time, and it is one which is constantly operative at the 

 surface of the planet, — slowly, very slowly, at the present day, it is 

 true, because the amount of carbonic acid in the atmosphere is now 

 very much less than it was at this former time. 



Thus you see the result of this subaerial decomposition of these 

 rocks gives rise to clay ; but the carbonate of soda going down into 

 the sea decomposes the lime-salts in the sea : and precipitates 

 carbonate of lime, — in other words, limestone. First, the action 

 gives rise to solid quartz-silica ; secondly, to the formation of clay ; 



