AFRICAN EXPLORERS OF THE NINETEENTH CENTURY. 135 
empire in the north and west of Africa, and also that 
beyond a doubt they did not belong to the negro race. 
The study of their language, and its resemblance to 
certain idioms not of African origin, will some day throw 
a light on the migration of races. Lastly, Lake Tchad 
had been discovered, and though not entirely examined, 
the greater part of its shores had been explored. It had 
been ascertained to have two tributaries : the Yeou, part 
of whose course had been traced, whilst its source had 
been pointed out by the natives, and the Shari, the 
mouth and lower portion of which had been carefully 
examined by Denham. With regard to the Niger, the 
information collected by Clapperton from the natives 
was still very contradictory, but the balance of evidence 
was in favour of its flowing into the Gulf of Benin. How¬ 
ever, Clapperton intended, after a short rest in England, 
to return to Africa, and landing on the western coast, 
make his way up the Quorra, or Djoliba, as the natives 
call the Niger ; to set at rest once for all the dispute as 
to whether that river was or was not identical with the 
Nile; to connect his new discoveries with those of 
Denham, and lastly to cross Africa, taking a diagonal 
course from Tripoli to the Gulf of Benin. 
