2^2 The National Geographic Magazine 



SUR La 



part of Europe. China is throughout 

 a thickly populated country, but its 

 greater cities are drawn toward the coast 

 and lie principally in a crescent-shaped 

 mass from the mouth of the Hoang-ho 

 to the mouth of the Si-kiang. In the 

 same way the cities of India crowd into 

 the valley of the Ganges, and the great 

 bulk of the city population of Europe 

 lies in the narrow ellipse of which 

 Berlin and lyondon are the two foci. 



THREE ORGANIZED AREAS 



The area which we are considering, 

 therefore, instead of being one of a gen- 

 eral and indiscriminate population , is dif- 

 ferentiated into three masses, into cities 

 far apart on the east, the west, and the 

 south of the Eurasian mass. The history 

 of the world for many thousand years 

 has been the history of the interaction 

 of these three great masses of city popu- 

 lation. Each demands in part what only 

 the other two can furnish. For each 

 of the three great masses, as in all 

 economic integers, prosperity rests not 

 merely upon the continuous and sym- 

 metrical development of internal re- 

 sources, but also and still more upon 

 that narrow margin of advance and 



profit which comes 

 from advantage- 

 ous exchange. 

 When these three 

 masses of popula- 

 tion, which early 

 formed themselves 

 into cities — for the 

 present cities of 

 northern Europe 

 are the direct de- 

 scendants of a sim- 

 ilar ellipse of cities 

 along the Mediter- 

 ranean and which 

 still have their rep- 

 resentatives there 

 — enjoy a full, un- 

 broken exchange, 

 these three groups 

 are prosperous. When an interruption 

 occurs in this exchange, there come, in 

 any one of the three which is in a posi- 

 tion most to feel the interruption, eco- 

 nomic depression, disaster, revolution, 

 extending perhaps to a social cata- 

 clysm. This often arises not because 

 interruption of free intercourse between 

 these three great groups of cities would 

 alone have caused catastrophe, but be- 

 cause when many other causes of an in- 

 ternal character had combined to weaken 

 the social fabric, the shock which came 

 by the loss of this profit was sufficient 

 to destroy unstable equilibrium and to 

 bring a sudden ruin which otherwise 

 would have gone through a normal de- 

 generation and deterioration. So far as 

 these groups appear on an ordinary map, 

 communication appears easy. A broad 

 extent of land connects all three, and 

 the ordinar}^ impression is one of con- 

 nection, and not separation, between the 

 different parts of this great land mass. . 



THE CORE OF ASIA 



These city groups lie outside the main 

 core of the continent. If the rude tra- 

 pezium which can be inscribed within 

 the continental mass of Asia be drawn 



