402 THEORIES RESPECTING THE NIGER* 
lake of Nigritia, (Nigrites Palus,) which lies in lat. 
15°, long. 18°. 
" And has formed two derivations* to the north, 
viz. to the mountains Sagapola and Usurgala — and 
one to the east upon the lake of Libya, (Libya Pa- 
lus,) which lies in lat. 35°, long. 16° 30'," 
Never, perhaps, has a more singular and unappro- 
priate description been given of a river, than this 
of its joining two mountains together. Ptolemy 
seems evidently to have considered merely the geo- 
metrical line described by the river course across 
Africa, without viewing it as a body in motion, 
His description can be correct only on one suppo- 
sition ; that of two rivers meeting in a common 
receptacle. With regard to the direction of the 
streams, the only ground on which an inference 
can be made, seems to be the following. There is 
no lake or other receptacle in the whole line of 
stream, except that of Nigritia, (Nigrites Palus,) for 
the Libya Palus is represented as situated in one of 
its tributaries. As it is placed very near the west- 
ern extremity, the greater portion, in order to find 
in it a receptacle, must flow westward. This is 
corroborated by the expression that the Niger forms 
* Exrgoiroi, divertigia. It deserves notice, that this term, 
though it seems to convey an opposite idea, has merely the 
common signification of a tributary stream. Thus (Lib. IV. 
c. 16.) we have " divertigium ad Emodos montes. Fons vero 
" in iis," and similar instances in the same and other chap- 
ter?, 
