OF THE UN/VERSE. ROMAN EMPIRE. 187 



this intercourse the knowledge of the Greek sphere, the 

 Greek zodiac, and the astrological planetary week, extended 

 to the last-named countries in the first centuries of our 

 era. ( 288 ) The great Indian mathematicians Warahamihira, 

 Bramagupta, and perhaps even Aryabhatta, are later than the 

 period of which we are treating ; ( 289 ) but it is also possible 

 that a partial knowledge of discoveries earlier made, in ways 

 distinct and apart in India itself and originally belonging 

 to that anciently civilized nation, may have been conveyed 

 to the countries of the West before Diophantus, through the 

 extensive commercial intercourse which took place under the 

 Lagidse and the Caesars. We do not here undertake to dis- 

 tinguish accurately what belongs to each nation and to each 

 epoch ; it is enough if we point out the channels which were 

 opened to the communication and interchange of ideas. 



The gigantic works of Strabo and of Ptolemy testify in 

 the most lively manner the increase which had taken place 

 in these channels and in general international intercourse. 

 The ingenious geographer of Amasia had not Hipparchus's 

 exactness of measurements or the mathematical views of 

 Ptolemy ; but his work surpasses all the geographical writings 

 of antiquity both in grandeur of plan and in the variety and 

 abundance of materials. Strabo, as he takes pleasure in 

 telling us, had seen with his own eyes a considerable part of 

 the Koman empire, " from Armenia to the Tyrrhenian coasts, 

 and from the Euxine to the borders of Ethiopia." After 

 having completed forty-three bocks of history as a continuation 

 of Polybius, he had the courage in the eighty-third year of 

 his age ( 29 ) to commence his great geographical work. 

 He reminds liis readers " that in his time the power of the 

 Eomans and of the Parthians had opened the world even 



VOL. II. O 



