THE HUMAN SPECIES. 79 



CURRENTS OF THE MEDITERRANEAN. 



BUT the isthmus, connecting Egypt with Asia, did not 

 exist at the commencement of the present geological 

 arrangement. TJie Arabian prolongation of volcanic 

 galleries, may, indeed, have dug the channel of the Red 

 Sea, since, on the Abyssinian sides, mephitic lakes and 

 a sulphurous soil, reach from the coast to the mountains, 

 and chains of dormant craters, pass behind the coast, 

 in a south-east direction, even beyond the equator. 

 vSo, likewise, on the west of the Nile, extensive tracts, 

 bordering on the desert, manifest igneous activity, not 

 far below the surface, in ebullitions assuming various 

 fantastic forms. From the period, however, when the 

 Straits of Calpe, the Bisepharat of Phoenician naviga- 

 tors, admitted the Western Ocean to give the present 

 form and extent to the Mediterranean, anteriorly sup- 

 plied with very little fresh water, it may be supposed, 

 that the evaporation, being more counterbalanced by 

 the influx, passing mostly eastward in the straits, and 

 still more at a great depth below the surface, raised the 

 sea to a higher level, and caused the circular course, 

 which now flowing eastward, along the coast of Bar- 

 bary, casts all river deposits brought down that shore 

 into the recess of the two Syrtes, and near the summit 

 of the Mediterranean, sweeps onwards all the Nilotic 

 discharges. At the commencement of the present super- 

 ficial terrene system, when the current first acted upon 



