APPENDIX. 
VU 
same region with that which he describes,* and who had entered more into the 
detail of the African geography, than any other, would, according to the 
Osual mode of decision, on such pretensions, be preferred to those who went 
before him, and had treated the subject in a more general way. Mankind had 
no criterion by which to judge of the truth. 
Since then the Arabian geographer, who had written the most extensively on 
the subject, had conducted the Niger into the Adantic, we cannot wonder 
that the early Portuguese discoverers, who doubdess learnt from the Arabian 
authors the pardculars of African geography, should adopt the same idea ; 
and that they should regard the Senegal river as the Niger-, as we find it, in 
the histories of their discoveries in the fifteenth century. The Portuguese, 
who at this period took the lead, in matters of navigation and discovery, 
might well be expected to set the fashion, in what related to African geography. 
So that in despite of Ptolemy, and of the ancients in general, the great inland 
river of Africa was described to run to the west; and to form the head of the 
Senegal river. Nay more, it was at last supposed to be the parent stock of 
all the great zvestern rivers of Africa. 
Sanuto, whose Geography of Africa, is dated 1 588, describes one branch 
of the Niger to be the Rio Grande, the other the river of Sestos ; regard- 
ing the Senegal as a different river. 
M. Delisle's map of Africa (1707) gives the Niger a direct coui"se 
through Africa, from Bornou, in the east, and terminating in the river of 
Senegal on the west. But in his maps of 1722 and 1727, this was corrected : 
the source of the Senegal was placed at a shallow lake named Materia, be- 
tween the 14th and 15th degrees of longitude east of Cape Verdj and in lati- 
tude 12"; whilst the river of'ToMBUcxoo, named Guien,wa.s described to issue 
from another lake, in the same neighbourhood, and to flow toivards Bornou, 
where it terminated in a third lake. 
The cause of this change, may be easily traced, in the intelligence collect- 
ed by the French traders and settlers in Gal lam :t the substance of which 
* He was commonly called the Nubian Geographer. 
f Gallam is one of the names of the country in which Fort St. Joseph is situated; and 
is often applied to the^ettlement itself. 
