PHYSICAL CONTEMPLATION OF THK UNIVERSE. 123 



"Tie existence of the Arabian Gulf as the result of tho ir- 

 iy tion of the Indian Ocean through the Straits of Bab-el- 

 Mandeb belongs to a series of great physical phenomena, 

 which could alone have been revealed to us by modern geog- 

 nosy. The European continent has its main axis directed 

 from northeast to southwest ; but almost at right angles to 

 this direction there is a system of fissures, which have given 

 occasion partly to a penetration of sea-water, and partly to 

 the elevation of parallel mountain chains. This inverse line 

 of strike, directed from the southeast to the northwest, is dis- 

 cernible from the Indian Ocean to the efflux of the Elbe in 

 Northern Germany ; in the Red Sea, the southern part of 

 which is inclosed on both sides by volcanic rocks ; in the Per- 

 sian Gulf, with the deep valleys of the double streams of the 

 Euphrates and the Tigris ; in the Zagros chain in Luristan ; 

 in the mountain chains of Hellas, and in the neighboring isl- 

 ands of the Archipelago ; and, lastly, in the Adriatic Sea, 

 and the Dalmatian calcareous Alps. The intersection* of 

 these two systems of geodetic lines directed from N.E. to S.W., 

 and from S.E. to N.W. (the latter of which I consider to be 

 the more recent of the two), and whose cause must undoubt- 

 edly be traced to disturbances in the interior of our planet, has 

 exercised the most important influence on the destiny of man- 

 kind, and in facilitating intercourse among different nations. 

 This relative position, and the unequal degrees of heat experi- 

 enced by Eastern Africa, Arabia, and the peninsula of West 

 ern India at different periods of the year, occasion a regular 

 alternation of currents of air (monsoons), favoring navigation 

 to the Myrrhifera Regio of the Adramites in Southern Arabia, 

 to the Persian Gulf, India, and Ceylon ; for, at the season of 

 the year (from April and May to October) when north winds 

 are prevailing in the Red Sea, the southwest monsoon is 

 blowing from Eastern Africa to the coast of Malabar, while 

 the northeast monsoon (from October to April), which favors 

 the return passage, corresponds with the period of the- south 

 winds between the Straits of Bab-el-Mandeb and the Isthmus 

 of Suez. 



After having sketched that portion of the earth to which 

 foreign elements of civilization arid geographical knowledge 

 might have been conveyed to the Greeks from so many different 

 directions, we will first turn to the consideration of those na- 

 tions inhabiting the coasts of the Mediterranean who enjoyed 



* Leopold von Buch, Ueber die Geognoslischen Systeme von Deutsch- 

 land, s. xi. ; Humboldt, Asie Centrale, t. i., p. 284-286. 



