AjDpendix A. 



astroiiomif studies the eity of Alexuiidria aiul the oonimeieial empoiiuin of 

 Khapta, lead of themselves to tlie hj-pothesis that, ))esides the details gatliered 

 from the Greek seafarers along the east coast of Africa, the Alexandrian 

 Geographer also utilized the information obtained in the valley of the great 

 river itself. Nor will this assumption appear too liold if we l>ear in mind that 

 long before the time of Ptolemy, the great Eratosthenes, speaking of the chief 

 branch of the Nile, expressed himself thus : " Two waterways fall into the 

 Nile : they l>oth come from certain lakes lying far to the east and enclosing a 

 verv large island known bj- the name of Weroe. One of these waterways, 

 called Astaboras, forms the east side of the island, the other is called Astapus. 

 Some authors, however, gi\e to the latter the name of Astasobas, and apply 

 the name Astapus to another waterway, which they l)ring from the lakes lying 

 in the region of the south, and regard it in some way as the main stream or 

 else as the chief branch of the Nile, adding that its periodical floods are due to 

 the summer rains." ('■') If, as seems beyond diml>t, the Astaboras is to be 

 identified with the Atbara, the Astasolias with the Bahr el-Azrek or Blue Nile, 

 and the Astapus with the White Nile or Bahr el-Abiad (main branch of the 

 Nile), Ptolemy would have liut repeated on the whole what three centuries 

 Jiefore him had been so well expressed bj^ the Librarian of Alexandria, merely 

 adding on his own part the positions — latitude and longitude — of the two 

 lakes lying in the region of the south, that is, south of the equinoxial line 

 whose waters feed the chief artery of the all-important fluvial system. 



At this point we meet with an appaiently serious olijection. According to 

 the authors alluded to by Eratosthenes the name Astapus is given to the 

 principal luaneh of the Nile flowing from the south, whereas Ptolemy applies it 

 to an affluent of the Nile which, issuing from Lake Coloe under the ccjuinoxial 

 line, falls into the main stream at latitude 12° N. But, as above stated, the 

 objection is only apparent. Eratosthenes, speaking for himself, had already 

 given the name of Astapus to the river marking the west (and south-west) side 

 of the island (peninsula) of Meroe, that is to say, the Abai or Bahr el-Azrek. 

 Ptolem}', on his part, did not think it right to depart from the opinion of his 

 predecessor, and so kept the name of Astapus for the subordinate river. It 

 might be more important to notice in the (Geography of the Alexandrian two 

 errors, one of which aft'ects the Lake Coloe (Lake Tana or Tsana in the heart 

 of Abyssinia), which he places under the ccpiinoxial line. The other mistake 

 consists in describing the Astaboras as a river which mingles its waters with the 

 Astapus. But an enquiry into all these matters, besides reqtiiring too great a 

 development, would be foreign to the question of the lakes, sources of the Nile, 

 and to that of the MoiiiU.-iins of the Moon. Notice can only l)e taken of the 



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