XJRBANISM CLERGET. 



655 



on the Euphrates, to return to Seleucia on the Tigris. Even to-day 

 all the rivers bring together the most intense economic life. 



M. Paul Alougeolle has with i-eason remarked that at each succes- 

 sive period of the general history of the Western Empire the principal 

 centers of civilization have extended farther and farther from the 

 Tropics toward the polar circle.- This is shown by the following 

 table: 



FIRST PERIOD. 



SECOND PERIOD. 



THIRD PERIOD. 



In many ancient cities agriculture surpassed industrial and 

 commercial activities. Everywhere within the ancient cities were 

 found common pasturage lands, as at Palmyra, and it was the same 

 in many old medieval cities in France (Douai, Amiens, Aurillac, 

 Dole, etc.), in England, in Germany, and in Italy. Not only were 

 the inliabitants of the cities agriculturists, possessing fields outside 

 the cities, but urban space itself was in great part under cultivation. 

 The ancient writings make frequent mention of wide cultivated 

 tracts or of agricultural undertakings. These are chiefly gardens 

 and vineyards, but mention of arable fields are not rare. Sometimes 

 these cultivated tracts serve to separate the various quarters of the 



' Paul Mougeolle: Statique des civilisations. ParLs, 1883. 



