( 32G ) 



An Attempt to determine the mean height of Continents. By 

 Baron Von Humboldt. 



At the meeting of the Berlin Academy of Sciences, on 18th 

 July 1842, a memoir by M. de Humboldt was read, of which 

 we think it necessary to give a somewhat lengthened account. 

 It is entitled " An attempt at determining the mean height 

 of Continents." 



" Among the numerical elements on which the progress of 

 physical geography appears more particularly to depend, there 

 is one which no attempt has been hitherto made to determine. 

 The notion which seemed to prevail, that it was impossible 

 to come to such a determination, has perhaps been the prin- 

 cipal cause of the subject being neglected. However, the ex- 

 tension of our orographical knowledge, as well as the great- 

 er accuracy of the maps which represent large portions of 

 country, determined me, says M. de Humboldt, to undertake, 

 some years ago, a work of great labour, and in appearance 

 barren in results, the object of which is the knowledge of the 

 mean height of continents, and the determination of the mean 

 height of the centre of gravity of their volume. In such a case 

 as this, as with many others, such as the dimensions of the 

 globe, the probable distance of the fixed stars, the mean tem- 

 perature of the poles of the earth, the thickness of the atmo- 

 spheric stratum above the level of the sea, or the enumeration 

 of the general population of the globe, we arrive at limited 

 numbers, between which the results must fall. In like man- 

 ner, it is by the perfect knowledge of the geometrical and 

 hjpsometrical surface of a country, of France, for example, 

 that we may thus be led, by analog}^ to extend the conclu- 

 sions to a great part of Europe and America, and ai'e en- 

 abled to establish numerical data, which have recently been 

 completed in a very satisfactory manner in regard to central 

 and western Asia. 



" It was likewise necessary to collect, with the greatest care, 

 astronomical determinations of the height of places, in order 

 to establish, to about 300 or 400 metres of absolute height, 

 the limits between the acclivities of the mountains and the 

 edges of the valleys. I long since demonstrated the possibi- 



