524 THE POPULAR SCIENCE MONTHLY. 



into sulphuric acid as the temperature moderated. Inasmuch as sea- 

 salt, water and silica, when heated together in a confined space, form 

 hydrochloric acid and sodium silicate, it is probable that in these early 

 times the saline residues were decomposed, and the chlorine set free to 

 combine with the hydrogen, and thus manufacture hydrochloric acid 

 on a large scale. The solid bases, therefore — lime, magnesia, soda, 

 potash, and the metals — would be combined into a great slag, and va- 

 rious minerals would crystallize out from it while cooling. By loss 

 of heat the slag would contract irregularly, and there would be ine- 

 qualities upon the surface, hills and valleys without system or order. 



Some authors think the salt would be volatilized, and form a zone 

 at the base of the atmosphere. The papers of Hunt, Forbes, Wurtz, 

 Winchell, and others, show that authors cannot yet agree upon the 

 details of those wonderful changes. The sources of our information 

 are meagre, and the opportunity for diverse views is easy, where such 

 immense periods of time are concerned, so that this discordance is not 

 strange. We cannot regard Dr. Hunt's illustration as perfect, since 

 the earth may never have been a fused mass of equal density through- 

 out, the concentric zones having been essentially segregated in the 

 nebulous period. 



The atmosphere may possibly have been arranged in zones. Con- 

 taining the present gases encircling the crust, the carbonic acid de- 

 rived from coal and the carbonates, the sulphurous and hydrochloric 

 acids, water converted into steam, and possibly volatilizable com- 

 pounds, it would constitute an atmosphere of extraordinary density 

 and insalubrity, perhaps six or seven times heavier than at present. 

 We may suppose that the law of diffusion of gases is subordinate to 

 that of gravitation ; whence there would result four zones, viz., sul- 

 phuric and hydrochloric acids at the base, surmounted first by carbonic 

 acid, and then by a mixture of nitrogen and oxygen ; and, lastly, by 

 steam. This dense gaseous covering would prevent much of the ra- 

 diation of heat from the earth, and produce a universal tropical climate. 



As the steam lies nearest the cooling influences of space, it would 

 be the first to be affected by radiation. Drops of water would aggre- 

 gate and descend, which would be vaporized again explosively, when 

 brought in contact with hot surfaces. The cooling influence increasing 

 its power, the number of falling drops increases, but they continuously 

 return to the outer envelope, till the crust is sufficiently thick and cool 

 to retain them. Thus, at the beginning of this age, there was a terri- 

 ble conflict between the clouds and the earth, the former pouring down 

 streams of water, which the latter refuse to receive ; but the clouds 

 eventually gain the mastery, and the earth sullenly evolves simmering 

 masses of vapor from a hot-water bath. 



Imagine, now, the earth capable of holding the falling drops. The 

 water will descend in torrents, for there is to be a transference of the 

 entire ocean from the upper atmospheric zone to the solid earth, where it 



