ICO COSMOS. 



of the sea, and thai the calcareous and the curved strata of 

 the Devonian basin penetrate twice that depth. If we com- 

 pare these subterranean basins with the summits of mountains 

 that have hitherto been considered as the most elevated por- 

 tions of the raised crust of the Earth, we obtain a distance of 

 37,000 feet (about seven miles), that is, about the j-^th of 

 the Earth's radius. These, therefore, would be the limits of 

 vertical depth and of the superposition of mineral strata to 

 which geognostical inquiry could penstrate, even" if the gener- 

 al elevation of the upper surface of the earth were equal to 

 the height of the Dhawalagiri .n the Himalaya, or of the 

 Sorata in Bolivia. All that lies at a greater depth below the 

 level of the sea than the shafts or the basins of which I have 

 spoken, the limits to which man's labors have penetrated, 01 

 than the depths to which the sea has in some few instances 

 oeen sounded (Sir James Ross was unable to find bottom with 

 *,7,600 feet of line), is as much unknown to us as the interior 

 \>f the other planets of our solar system. We only know the 

 xiass of the whole Earth and its mean density by comparing 

 1 1 with the open strata, which alone are accessible to us. In 

 the interior of the Earth, where all knowledge of its chemical 

 and mineralogical character fails, we are again limited to as 

 pure conjecture, as in the remotest bodies that revolve round 

 the Sun. We can determine nothing with certainty regard- 

 ing the depth at which the geological strata must be supposed 

 to be in state of softening or of liquid fusion, of the cavities 

 occupied by elastic vapor, of the condition of fluids when 

 heated under an enormous pressure, or of the law of the in- 



nosist, Von Dechen, for the following observations. " The depth of 

 the coal basin of Liege, at Mont St. Gules, which I, in conjunction with 

 our friend Von Oeynhausen, have ascertained to be 3890 feet below 

 the surface, extends 3464 feet below the surface of the sea, for the ab- 

 solute height of Mont St. Gilles certainly does not much exceed 400 

 feet ; the coal basin of Mons is fully 1865 feet deeper. But all these 

 depths are trifling compared with those which are presented by the 

 coal strata of Saar-Revier (S.iarbrUcken). I have found, after repeated 

 examinations, that the lowest coal stratum which is known in the neigh- 

 borhood of Duttweiler, near Bettingen, northeast of Saarlouis, must de- 

 scend tc depths of 20,682 and 22,015 feet (or 3-6 geographical miles) 

 below the level of the sea." This result exceeds, by more than 8000 

 feet, the assumption made in the text regarding the basin of the D- 

 vonian strata. This coal-field is therefore sunk as far below the sur- 

 face of the sea as Chimborazo is elevated above it at a depth at which 

 the Earth's temperature must be as high as 435 F. Hence, from the 

 highest pinnacles of the Himalaya to the lowest basins containing tha 

 revelation of an earlier world, there is a vertical distance of abouJ 

 . 48 000 feet, cr of the 435th part of the Earth's radius. 



