Febeuaet 26, 1909] 



SCIENCE 



325 



America in the south, but in Europe, in 

 the north. The southwest winds blow in 

 peninsular North America mostly during 

 the summer; in Europe, however, during 

 the winter, just at the time when cold 

 northwest winds bring cold waves to the 

 United States, and similar temperature is 

 met with in very different latitudes of both 

 sides of the Atlantic. Indeed, the climate 

 on both sides of an ocean can not be the 

 same; there must be differences between 

 the east and west shores of the continents. 

 Europe has the true climate of the west 

 coast of a continent. The climate of this 

 side of the Atlantic has its exact counter- 

 part in North America in British Colum- 

 bia, and the Mediterranean climate reoc- 

 curs in all of its characteristic features 

 farther south in California. The high 

 elevations of the mountains of British 

 Columbia and of the Sierra Nevada, how- 

 ever, hinder the extension of these climatic 

 conditions into the interior of the conti- 

 nent, while the open west of Europe allows 

 the western winds to carry their moisture 

 very far into the interior, and the long 

 extent of the Mediterranean Sea is accom- 

 panied by a climate like that of California 

 from the south of Spain over the south of 

 Italy and Greece as far as Asia Minor. 

 Thus one very large climatic province of 

 very uniform character extends between 

 the Atlantic Ocean and those semi-arid 

 regions in which the higher civilization of 

 the Orient in ancient times was born. And 

 this climatic province possesses many fea- 

 tures similar to those of semi-arid regions. 

 This fact is of the greatest importance for 

 the evolution of civilization in Europe. 



"We can trace back the European popula- 

 tion very far. Man witnessed in Europe 

 ' that set of climatic changes which charac- 

 terize the great ice age, but while it is still 

 open to discussion whether the present pop- 

 ulation of Europe had its origin in that 



very old one or whether it came from Asia, 

 there can be no doubt that the European 

 civilization has its root in the Orient. Here 

 in Mesopotamia and in Egypt an early 

 civilization arose under arid and semi-arid 

 conditions, based on irrigation; this civil- 

 ization was brought by early navigators 

 over the whole basin of the Mediterranean 

 and it found congenial conditions every- 

 where along the shores. In America such 

 an evolution was impossible. Indeed, an 

 original civilization has grown up here 

 under semi-arid conditions, and it was 

 based, too, on irrigation. This is not sur- 

 prising. Irrigation is the easiest way to 

 introduce agriculture. It is only necessary 

 to distribute water and crops become pos- 

 sible. There is not necessary the very dif- 

 ficult work of clearing the forests. But a 

 certain political organization is necessary 

 which begins at the moment when the rules 

 are established according to which the 

 water is distributed. 



The conditions under which the early 

 civilization on the plateau of Mexico was 

 developed are, indeed, in many respects 

 similar to those of the Orient. That civil- 

 ization, however, was not only far more 

 feeble than that of the Orient, but it could 

 not extend in the same way. The Amer- 

 ican Mediterranean is far larger than that 

 between Europe and Africa, and early 

 navigation did not find here the same land- 

 marks which allowed the Phoenicians and 

 Greeks to sail so far, but above all the 

 shores of that sea were not as inviting to 

 settlers as those of Greece, Italy, Spain or 

 northern Africa. They are covered for a 

 wide extent by dense, tropical, nearly im- 

 penetrable forests, and a belt of those vir- 

 gin forests hindered the Mexicans from 

 extending their civilization down to the 

 Gulf of Mexico. At no time has this sea 

 played a role similar to the Mediterranean ; 

 a Roman empire could never grow up east 

 of the cradle of the American civilization 



