IN CENTRAL AFRICA. 323 
sition of the caravans^ and the physical condition of the 
travellers ; but^ as it was impossible to perform this work 
correctly, it would also have been useless. Besides, the 
reflections which I have already made tend to shew that, 
by following a uniform plan of reduction from one end of 
the route to the other, one must arrive at a result nearly 
approaching to the truth. 
All that I have hitherto advanced relates solely to 
that part of the general map, which represents the space 
travelled over by M. Caillie ; I have now to speak of the 
remainder, namely, the extremity of the map towards the 
north, and that towards the S. W. The former portion, 
or the country of Morocco, has been chiefly extracted' 
from the fine map of M. Brue,* but reduced to much 
fewer details j we know that he sought his data in the 
best Spanish and English maps, and in the works of 
Badia, Jackson, Walckenaer, Ritter, &c. ; authorities 
which furnish excellent materials, but which, the former 
especially, must not always be employed without the 
assistance of criticism. 
The second part, to the south of the Rio-Nunez, has 
been drawn from the Senegambie of M. Dufour, who has 
skilfully combined the materials of Major Laing with those 
of preceding English travellers : it will be seen by com- 
paring our two maps, that I have been obliged to differ 
from him with respect to the situations and names of 
several countries. 1 have also been necessitated, as well for 
* Carte generale des Etats da Nord de VAfrique, 8fc, 
Y 2 
