292 ANNUAL OP SCIENTIFIC DISCOVERY. 



the large quantities of sal-ammoniac that are known to occur; but, rather, he 

 argues by analogy that probably not only titanium, but other metals, such as 

 iron, and probably even hydrogen, may combine directly with nitrogen in the 

 interior of the globe, under conditions of great pressure, and other circum- 

 stances likely to modify the nature of those reactions which take place under 

 our eyes. In a postscript the author adverted to the recently discovered fact, 

 that boron, like titanium, has the property of combining directly with the 

 nitrogen of the air, and that the compound which it forms with it also pos- 

 sesses the property of evolving ammonia under the influence of the alkaline 

 hydrates. 



ON THE CHEMISTRY OF THE PRIMEVAL EARTH. 



The primitive rocks which filled so large a place in the geological systems 

 of the last century, are now being forgotten. We have learned that the old- 

 est visible portions of the earth's crust are made up of sediments, the ruins 

 of still older rocks, which were as varied in their character as are their deriv- 

 atives. The primeval substratum has thus constantly receded before ad- 

 vancing science, and we are led to the conclusion that mechanical and chem- 

 ical conditions similar to those of the present epoch presided over the forma- 

 tion of the most ancient rocks known. 



But although the materia prima of the sedimentary rocks has long since 

 been buried beneath its own ruins, its nature offers an interesting subject of 

 consideration to the chemical geologist. If we admit the igneous theory of 

 the earth, we may obtain a conception of the nature of the once liquid globe 

 and of its atmosphere, by supposing the now existing matters of the earth's 

 crust and surrounding fluids to be made to react upon one another under the 

 influence of an intense heat. The quartz would decompose the carbonate of 

 lime with the production of silicate and the liberation of carbonic acid, 

 whose volume would be farther augmented by the combustion of all the 

 mineral carbon at the expense of the atmospheric oxygen. The reaction 

 between quartz and the chlorids of the sea, in the presence of aqueous' vapor, 

 would result in the formation of silicates and hydrochloric acid, while the 

 sulphur would likewise be liberated as a volatile acid. 



From these reactions there would result on the one hand a more or less 

 homogeneous mass of silicates of alumina and alkalies, with silicates of lime, 

 magnesia and iron, a mixture probably resembling dolerite, while the atmos- 

 phere would be made up of watery vapor, nitrogen, a probable excess of 

 oxygen, with carbonic, sulphuric and hydrochloric acids, representing all the 

 carbon, sulphur, and chlorine of the globe. 



When the cooling of the globe had so far advanced as to allow of the pre- 

 cipitation of water from this dense atmosphere, it would descend as an acid 

 rain, which attacking, at an elevated temperature, the silicates, would give 

 rise to chlorids of calcium, magnesium and sodium, mingled with sulphates 

 of these bases. The liberated silica would probably separate during the 

 cooling of the heated waters in the form of quartz. 



The subsequent decomposition of the exposed portion of the primeval 

 crust would result in the conversion of its feldspar into kaolin, and a soluble 

 alkaline silicate, which, decomposed by excess of carbonic acid, would be 

 carried to the sea as a bicarbonate; where, decomposing the lime salt, it 

 would give rise to chlorid of sodium and bicarbonate of lime", which would 

 be partly precipitated in a crystalline form, and partly secreted by marine 



