Scientific Intelligence — -Geology. 399 



and 1 7 1 -t feet ; the relative depths of these respectively are only 

 626 and 260. The absolute depth of the rich workings in Joach- 

 inisthal, Bohemia, is 1919 feet ; but taking the height of the surface 

 upon Declieu's estimate at 2250 feet above the level of the sea, it is 

 obvious that there the sea level has not even been attained. In the 

 Ilarz, the workings in the Samson pit, at Andreasberg, are carried 

 on at the absolute depth of 2062 feet. In Old Spanish America, 

 I know of no deeper mines than those of Valenciana, near Guanax- 

 uato, Mexico ; I found the Planes de San Bernard 1582 feet deep ; 

 but this mine does not reach the level of the sea by 5592 feet. If 

 we compare the depth of the old Kuttenberg works (a depth which 

 exceeds the height of the Brocken, and only falls short of that of 

 Etna by 200 feet) with the heights of the loftiest buildings that 

 have been reared by man (the Pyramid of Cheops and the Minster 

 at Strasburg\ we find that the mines are to these in proportion of 

 8 to 1. 



Basin-shaped curved strata, which dip down on one hand and rise 

 at a measureable distance, although not penetrated by mines or 

 shafts, still suffice to give us accurate information of the constitution 

 of the crust of the earth at great depths from the surface. I have 

 to thank the excellent geologist M. Von Dechen for the following : — 

 He writes to me, " The depth of the coal measures at Mont St Gilles, 

 Liege, which our friend M. Von Oeynhausen has estimated at 3650 

 feet below the surface, must lie at the deptli of 3250 feet below the 

 sea level, inasmuch as Mont St Gilles is certainly not 400 feet 

 high ; and thecoal basin at Mens lies fully 1750 feet deeper. These 

 depressions, however, are trifling when compared with that of the 

 coal strata of the Saar-Revier (Saarbriicken). After i-epeated trials, 

 have found that the lowest coal strata known in the country of Dutt- 

 weiler near Bettingen, north-eastward from Saarlouis, dip 19,406, 

 and 20,656 feet under the level of the sea." This conclusion ex- 

 ceeds by 8000 feet the estimate which I have given in the text of 

 Cosmos for the basin of Devonian strata. These Belgian coal mea- 

 sures, therefore, lie as far below the level of the sea as Chimborazo 

 rises above it, at a depth where the temperature of the earth must 

 be 224^ C. (435° F.). From the highest summit of the Himalaya 

 to the bottom of this basin, containing vegetable remains of the 

 primeval world, we have a perpendicular depth of 45,000 feet, I. e., 

 jyy of the semi-diameter of the earth. 



I have thought it important thus to bring together these data in 

 relation to the absolute and relative depths that have been reached 

 by man, a subject in connection with which many errors have been 

 constantly committed, principally, as it seems, through faulty reduc- 

 tions of the measurements from one standard to another. On pro- 

 ceeding eastward from Jerusalem toward the Dead Sea, a prospect is 

 gained which, according to our present hypsonietrical knowledge, is 

 unparalleled on the face of the earth. Tiicre, on approaching the 



