250 The National Geographic Magazine 



is very large — arid it is larger in the case 

 of Europe than any other — the access of 

 perturbing influence will be frequent ; 

 if it is small the reverse will be true.^ 



Asia, largest in absolute area, stands 

 midway with reference to the ratio which 

 its coast-line bears to its area between 

 the six great divisions into which the 

 earth's surface is usually divided, three 

 of which were known to the earliest 

 geographers of the region of which we 

 are treating — a region which stands at 

 the junction of the three. The ratio 

 is smaller than it is in the case of Eu- 

 rope or North America ; it is larger 

 than that of Australia, Africa, or 

 South America. A priori, therefore, 

 we might simply, with these relations 

 before us, if we were dealing with the 

 affairs of an unknown planet of which 

 we knew only the facts presented by 

 these areas and circles, conclude that the 

 most mobile conditions would exist in 

 the continent named Europe ; that these 

 would be shared by North America ; 

 that the affairs of Asia would offer a 

 mean between the extreme activity of 

 Europe and the extreme immobility in 

 the history and development of Austra- 

 lia. The problem which we have to con- 

 sider with our larger knowledge is to 

 determine the interaction which these 

 varying relations of area and coast-line 

 have created between the three contig- 

 uous continents with which we have to 



deal, whose natural mean term and link 

 is southwestern Asia. 



THE RED SEA RIFT 



With the general characteristics of 

 Asia you are already familiar. As I 

 present to you the Eurasian conti- 

 nent,^ you recognize instantly that its 

 central core is that great east-and-west 

 uplift whose western center is the Alps 

 and whose eastern upheaval is the great 

 boss of central Asia, too large to be desig- 

 nated by any one term. This great and 

 continuous chain is crossed at right an- 

 gles upon the earth's spheroid by that 

 long drawn rift or gap which extends 

 from the hollow valleys of Coele-Syria to 

 lyake Tanganyika and beyond, to which 

 attention was first called by Suess, and 

 which has been more fully discussed by 

 the English geographer, Mr. J. W. 

 Gregory.* This range extends in its 

 subordinate forms to the very edge of 

 that other great rift — part of that circle 

 of fire which rings the Pacific. Prop- 

 erly speaking, one might say there are 

 three great lines of volcanic action : 

 one old, which lies at right angles to 

 the great Eurasian uplift, and which 

 is in a condition which, in the case of 

 a river, we should call its last stage ; 

 one in its mid-stage of activity, extend- 

 ing parallel to it along the eastern coast 

 of Asia, and a third, which appears. 



"The figures as to the area of the continents are necessarily mere approximations, 

 following table gives the outline as presentedby M. Elisee Reclus : 



The 



Europe. 



Asia. 



Africa. 



N. America. IS. America. 



Australia. 



Total area, square miles . 



Mainland, square miles. 



Development of coast- 

 line, miles 



Accessible coasts 



Ratio of the geometrical 

 to the actual contour . 



4,005,100 

 3,758,300 



18,600 

 17,610 



I :2.5 



17,308,400 

 15,966,000 



34.110 

 28,200 



I :2.5 



11,542,400 

 11,293,930 



16,480 

 18,480 



9-376,850 

 7,973,700 



30,890 

 26,510 



I :3.i 



6,803,570 

 6,731,470 



16,390 

 . 16,390 



3,450,130 

 2,934,500 



io,57<3 

 14,400 



I.: 1.7 



'Relief Sketch Map of Eurasia, Lambert's Projection, Butler's School Geographies. 



' " Das Antlitz der Erde," Suess, Edouard, and "The Great Rift Valley," Gregory, J. W.,1896. 



