386 
GEOGRAPHICAL SYSTEMS 
very ample opportunities of becoming acquainted 
with this part of the continent. They have left, 
accordingly, fuller descriptions than the ancients 
of the known parts, and have adopted, with regard 
to the unknown, an entirely different train of hy- 
potheses. While Herodotus, Mela, and Pliny, 
made the central river of Africa run towards the 
east, and fall into the Nile, the Arabians, on the 
contrary, supposed it to flow westward from a com- 
mon source with that river. To both they applied 
the common name of Nile ; one being the Nile 
of Egypt, and the other the Nile of the Negroes, 
Gana, situated upon the Nile of the Negroes, near- 
ly midway between its point of separation from that 
of Egypt and its termination, was the metropo- 
lis of all the Mahometan kingdoms, the main 
channel of communication with Northern Africa, 
and, consequently, the grand source from which 
information was drawn. At the distance of forty 
days' journey westward from Gana, this river fell 
into the sea, and near its mouth was Ulil, resort- 
ed to by all the states along the Nile for a supply 
of salt. If the position of Ulil could be fixed, it 
would afford a key to the whole system of Ara- 
bian geography ; but the investigation is attend- 
ed with considerable difficulty. The distances of 
forty days from Gana, and of one month from 
Agades, seem to place totally out of the question 
the idea of its being situated on the ocean j 
