Attempt to determine the mean height of Continents. 335 



not been sufficiently observed, is the continuity of a consider- 

 able elevation, east and west, between 35" and 36^° of lati- 

 tude, from Takbialoudag, in ancient Lycia, as far as the Chinese 

 province of Houpih, an elevation thrice intersected by meridian 

 chains (Zagros, in Western Persia, Bolos, in AflFghanistan, and 

 the chain of Assam, in the valley of Dzangho) from the west 

 to the east of this chain, from the parallel of Dicearchus, which 

 is at the same time that of Rhodes, Taurus, Elbrouz, Hindou- 

 Kho, and Kouen-Lun or A-Neoutha. In the third book of the 

 geography of Eratosthenes, we find the first germ of the no- 

 tion of a chain of mountains (Strabo, xv. p. 689, Cas.) run- 

 ning in a continuous manner, and dividing Asia into two 

 parts. Dicearchus perceived the connection between the 

 Taurus of Asia Minor and the snow-covered mountains of 

 Asia, which had acquired so mvxch celebrity among the Greeks 

 by the false accounts of those who had accompanied the 

 Macedonians. Importance was assigned to the parallel of 

 Rhodes, and to the direction of this endless chain of moun- 

 tains. The chlamy de of Asia ought to be found further on under 

 this parallel (Strabo, xi. p. 519), and perhaps, says Strabo, a 

 little more to the east there may be another continent. The 

 Taurus and the plateaux of Asia Minor disclosed for the first 

 time to the Greek philosophers the influence of height on tem- 

 perature. " Even in the southern latitudes/' says the gi-eat 

 geographer of Amasis, (Strabo, ii. p. 73) when the climate of 

 the northern coasts of Cappadocia is compared with that of the 

 plains of Argaios, situated 3000 stadia further south, the 

 mountains and all the elevated lands are cold, even when 

 these lands consist of plains." Strabo is the only one among 

 Greek authors who has made use of the word ogomdtot or 

 mountain plain. 



According to the final result of the whole of M. de Hum- 

 boldt's investigations, the maximum assigned by Laplace for 

 the mean height of continents is too considerable by two-thirds. 

 He found the following numerical elements for the three 

 quarters of the world which have been the object of his cal- 

 culations (Africa not yet presenting a sufficient number of 

 data to be included). 



