MOUNTAIN SYSTEMS. 365 



practical seamen on the actual depths of tlie ocean ; and chapter 

 soundings have been made to a depth of 8540 feet ^^^'^^^- 

 without finding a bottom ; so that, so far from the ocean Soimdinga 

 being only a repetition, in an inverse ratio, on an infe- " ''ocean, 

 rior scale, of relative depressions corresponding to the 

 elevation on the earth's surface, it seems now probable 

 that the bed of the ocean exceeds in depth, by five or 

 six times, the elevation of the earth's heights. 



Manj' of the most remarkable investigations pursued Abstruse 

 by Humboldt, as the results of his study of the pheno- yons. 

 mena noted by him during his residence on the Asiatic 

 continent, are of so complex and abstruse a nature, as to 

 render it extremely difficult to reduce them to a popular 

 form. The conclusions, however, are in all cases re- 

 markable, and frequently of great practical value. Re- 

 marking on the singularity and uniformity of arrange- 

 ment discoverable in the mountain systems of Asia, our 

 traveller points out their apparent natural subdivision in- 

 to four systems, all running from west to east, along the 

 greatest breadth of the surface of the land ; while these, 

 again, are crossed by other mountain chains having a 

 meridional direction. Aiming at the discovery of some General 

 clearly pronounced indications of general laws, Hum- 

 boldt arrives at the conclusion that, in a portion of the 

 Asiatic continent most effectively surveyed by him, a 

 predominance of auriferous and platiniferous deposits is 

 clearly demonstrable in the latter mountain chains, or 

 those having a meridional direction. In these, as in so 

 many others of his most important conclusions as to 

 general laws, Humboldt was greatly assisted by his pre- 

 vious observation of the same class of phenomena, exhi- 

 bited on so gigantic a scale in the New World. In the Phenomena 



of the New 

 Andes, in the southern AUeghanies, and in the moun- world. 



tains of Brazil, all his conclusions pointed to similar 

 results, and led to his adopting the opinion that this 

 remarkable law was demonstrable in regard to the auri- 

 ferous alluvions of the American continent. Hence the 

 great value of the conclusion, put forth in the " Re- 



