150 COSMOS. 



greater than those to which human labour has been enabled 

 to penetrate. We are able to give in numbers the depth of 

 the shaft where the strata of coal, after penetrating a certain 

 way, rise again at a distance that admits of being accurately 

 defined by measurements. These dips show that the carbo- 

 niferous strata, together with the fossil organic remains which 



biihel reached England at an early period, for I find it remarked in Gilbert, 

 de Magnets, that men have penetrated 2400 or even 3000 feet into the 

 crust of the earth. (' ' Exigua videtur terrse portio, quse unquam hominibus 

 spectanda emerget aut eruitur; cum profundius in ejus viscera, ultra efflo- 

 rescentis extremitatis corruptelam, aut propter aquas in magnis fodinis, 

 tanquam per venas scaturientes aut propter aeris salubrioris ad vitam ope- 

 rariorum sustinendam necessarii defectum, aut propter ingentes sumptus 

 ad tantos labores exantlandos, multasque difficultates, ad profundiores 

 terra? partes penetrare non possumus ; adeo ut quadringentas aut [quod 

 rarissime] quingentas orgyas in quibusdam metallis descendisse, stupendus 

 omnibus videatur conatus." Gulielmi Gilberti, Colcestrensis, de Magnete 

 Physiologia nova. Lond., 1600, p. 40.) 



The absolute depth of the mines in the Saxon Erzgebirge, near Freiburg, 

 are : in the Thurmhofer mines, 1944 feet ; in the Honenbirker mines, 

 1827 feet ; the relative depths are only 677 and 277 feet, if, in order to 

 calculate the elevation of the mine's mouth above the level of the sea, we 

 regard the elevation of Freiburg as determined by Reich's recent observa- 

 tions to be 1269 feet. The absolute depth of the celebrated mine of 

 Joachimsthal in Bohemia (Verkreuzung des Jung Hauer Zechen-und 

 Andreasganges), is full 2120 feet; so that, as Von Dechen's measurements 

 show that its surface is about 2388 feet above the level of the sea, it fol- 

 lows that the excavations have not as yet reached that point. In the Harz, 

 the Samson mine at Andreasberg, has an absolute depth of 2197 feet. In 

 what was formerly Spanish America, I know of no mine deeper than the 

 Valenciana, near Guanaxuato (Mexico), where I found the absolute depth 

 of the Planes de San Bernardo to be 1686 feet ; but these planes are 5960 

 feet above the level of the sea. If we compare the depth of the old Kut- 

 tenberger mine (a depth greater than the height of our Brocken, and only 

 200 feet less than that of Vesuvius) with the loftiest structures that the 

 hands of man have erected, (with the Pyramid of Cheops and with the 

 Cathedral of Strasburg,) we find that they stand in the ratio of eight to 

 one. In this note I have collected all the certain information I could find 

 regarding the greatest absolute and relative depths of mines and borings. 

 In descending eastward from Jerusalem, towards the Dead Sea, a view 

 presents itself to the eye, which, according to our present hypsometrical 

 knowledge of the surface of our planet, is unrivalled in any country ; as 

 we approach the open ravine through which the Jordan takes its course, 

 we tread, with the open sky above us, on rocks which, according to the 

 barometric measurements of Berton and Russegger, are 1385 feet below 

 the level of the Mediterranean. (Humboldt, Asie CentraJe, th. ii. p. 323.) 



