62 DISCOVERIES OF THE PORTUGUESE* 
through toils and perils, on the shores of these bar- 
barous rivers, what a diligent search would easily 
have enabled them to discover at home in equal 
abundance. 
The great desert is also described. It is repre- 
sented as beginning at Cape Blanco, whence, spread- 
ing like a robe, with the river Senegal for its bor- 
der, it wraps round the continent till it comes to 
drink the waters of the Nile, which communicate 
to it some portion of moisture. The territory, how- 
ever, is not so wholly barren, but that it is peopled 
in spots called Abeses (oases). Of this territory, 
there are three kinds : That which is poorly co- 
vered with grass and shrubs, is called Azagar ; 
that composed of fine sand without verdure, Sa- 
hel ; that formed of small stones in the form of 
gravel, Sahara. 
Meanwhile, the progress of discovery was car- 
ried on rapidly in another direction. * The castle 
of Mina, upon the Gold coast, had been establish- 
ed as the centre of the Portuguese power, and as 
the point whence all further advances were to be 
made. It was now a long time since the sovereign 
pontiff had granted to the kings of Portugal the 
full dominion of all the lands which they should 
discover, from Cape Bojador to the Indies inclusive. 
This grant, made first to Henry, grandfather 
*Di Barros, III. 3. 
