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these minerals and metals came down in just the form and order that 

 we have indicated, or that they were regularly deposited, and left the 

 orderly traces that perhaps our hasty sketch would seem to imply. 

 There were unquestionably constant and profound commotions in the 

 atmosphere, and the commingling of the most diverse elements. 

 There were doubtless repeated meltings and chemical recombinations 

 at the surface, and the rending and comminuting of the newly-formed 

 crust by internal forces. The history of the earth's irregularities and 

 disorders forms the greater part of geology. But what we do claim 

 as certain is, that all the constituents of the outer shell of our globe 

 existed at one time as elemental gases above a sea of matter that was 

 held in condensation by superincumbent pressure ; that, as the earth 

 gradually cooled, these gases condensed somewhat in the order, in- 

 versely of their volatility, and directly of their nearness to the outer 

 bounds of the atmosphere, and fell to the surface like rain and snow 

 from water-clouds ; that they formed chemical combinations at the in- 

 stant of their condensation, or subsequently according to the power 

 of their affinities or the elements that were present ; and that, except- 

 ing the more recent displacements by mechanical forces, they now lie 

 in the earth as they fell from the heavens. 



The silica and silicates, which form the base, and by far the greater 

 part of the earth's crust, became oxides of their several elements be- 

 cause oxygen was the superabundant gas in its composition. There 

 have been worlds made up apparently without oxygen ; for the mete- 

 orites, which must be regarded as sample specimens from some stranger 

 world, however they may have been dispatched to us, are mostly com- 

 posed of pure crystalline and malleable iron, which could have cooled 

 into that condition only where there was no oxygen nor carbonic gases. 

 If chlorine had been our superabundant gas, the silicon would perhaps 

 quite as readily have united with it, and formed as stable a compound 

 as with oxygen. But the product, instead of being the hardest of 

 rocks, would have been a liquid very much resembling water, a little 

 heavier, and nearly as volatile, as the common ethers. In this case 

 there could have been no dry land, and no living beings that we can 

 conceive t>f. Eternal clouds and storms would have covered the face 

 of a surging boundless ocean. 



Hitherto, in our accounts of terrestrial phenomena, water has 

 played no part. It is probable that it was early formed, and in the 

 condition of vapor or steam diffused through the upper air. In this 

 state it bears the highest degree of heat that we can produce, without 

 decomposition. Hydrogen is the lightest of all the gases, and un- 

 questionably took its place on the outer limits of the atmosphere. 

 There it was brought into contact with oxygen by the commotion 

 of the elements, and converted into steam as fast as its lowering tem- 

 perature allowed of the combination. As we might expect from the 

 respective positions of the gases, all the hydrogen which fell to the 



