PHYSICAL GEOGRAPHY. 293 



shall be less surprised at the imperfect condition of meteor- 

 ology before the beginning of the present century ; since it is 

 only during the subsequent period that numerous accurate 

 observations on the temperature of the sea at different lati- 

 tudes and at different seasons, have been made and numeri- 

 cally compared together. 



The horizontal configuration of continents in their general 

 relations of extension, was already made a subject of intellec- 

 tual contemplation by the ancient Greeks. Conjectures were 

 advanced regarding the maximum of the extension from west 

 to east, and DicaBarchus placed it, according to the testimony 

 of Agathemerus, in the latitude of Rhodes, in the direction of 

 a line passing from the pillars of Hercules to Thine. This 

 line, which has been termed the parallel of the diaphragm of 

 Dictearchus, is laid down with an astronomical accuracy of 

 position, which, as I have stated in another work, is well 

 worthy of exciting surprise and admiration.* Strabo, who 

 was probably influenced by Eratosthenes, appears to have 

 been so firmly convinced that this parallel of 36 was the 

 maximum of the extension of the then existing world, that 

 he supposed it had some intimate connection with the form of 

 the earth, and, therefore, places under this line the continent 

 whose existence he divined in the northern hemisphere, 

 between Theria and the coasts of Thine. f 



As we have already remarked, one hemisphere of the 

 earth (whether we divide the sphere through the equator 

 or through the meridian of Teneriffe,) has a much greater 

 expansion of elevated land than the opposite one : these 

 two vast ocean-girt tracts of land, which we term the east- 

 ern and western, or the old and new continents, present, 

 however, conjointly with the most striking contrasts of con- 

 figuration and position of their axes, some similarities of 



Esdras. Columbus, who derived a great portion of his cosmographical 

 knowledge from the Cardinal's work, was much interested in upholding 

 this idea of the smallness of the sea, to which the misunderstood expres- 

 sion of " the ocean stream" contributed not a little. See Humboldt, 

 Examen critique de I' Hist, de la Geographic, t. i. p. 186. 



* Agathemerus, in Hudson, Geographi minores, t. ii. p. 4; see Hum- 

 boldt, Asie centr., t. i. pp. 120-125. 



t Strabo, lib. i. p. 65, Casaub; see Humboldt, Examen cr it., t. i. 

 p. 152. 



