Page:Popular Science Monthly Volume 4.djvu/542

524 into sulphuric acid as the temperature moderated. Inasmuch as seasalt, 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 various minerals would crystallize out from it while cooling. By loss of heat the slag would contract irregularly, and there would be inequalities 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 throughout, the concentric zones having been essentially segregated in the nebulous period.

The atmosphere may possibly have been arranged in zones. Containing the present gases encircling the crust, the carbonic acid derived from coal and the carbonates, the sulphurous and hydrochloric acids, water converted into steam, and possibly volatilizable compounds, 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., sulphuric 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 radiation 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 aggregate 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 terrible 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