AFRICAN EXPLORERS OF THE NINETEENTH CENTURY. 213 
Into the valuable work accomplished by the immediate 
successors of these pioneers in North Africa, Richardson, 
Barth, Oberweg, and their companions, we need not at 
TEE XILE. 
present enter. To Barth especially we are indebted for 
much of the knowledge we have of the Sahara, and the 
region around Lake Tchad and the Niger. 
