148 The National Geographic Magazine 



the continent." Today it is known 

 that this central area forms part of the 

 great Kongo Basin, with a population 

 of more than forty millions. 



In outlining the march of exploration 

 toward the interior of the " Dark Con- 

 tinent " only the most succinct account 

 is possible. For clearness of statement, 

 explorations are treated under five gen- 

 eral heads : First, trans-Saharan, from 

 the Mediterranean ; second', the Niger 

 regions ; third, the lake regions near 

 the Upper White Nile ; fourth, the 

 Zambezian region, and, fifth, the Kongo 

 Basin. 



According to different definitions of a 

 desert, the Sahara varies in area from 

 2,500,000 to 3,500,000 square miles, of 

 which the eastern third is generally 

 known as the Libyan Desert Hitherto 

 this desert area, with scant water, in- 

 tense heat, and whirling duststorms, 

 interposed an inaccessible barrier be- 

 tween the Hemitic nations of the Medi- 

 terranean coast and the negro tribes of 

 the Sudan. 



SAHARA'S BARRIERS OVERCOME 



Explorations of the Sahara were fruit- 

 less until Oudney, Denham, and Clap- 

 perton crossed (i 822-' 24) from Tripoli 

 to L,ake Chad, in the Sudan. Laing, fol- 

 lowing, crossed from Tripoli via Ghad- 

 ames and Tuat to Timbuktu, the mys- 

 terious city of strangely exaggerated 

 importance from previous centuries. 

 Panet, Vincent, Duveyrier, and Lenz 

 explored the desert between Senegal 

 and Southeastern Algeria. 



It was Barth who gave the first defi- 

 nite account of the Saharan region after 

 a journey of great extent and impor-' 

 tance. Starting from Tripoli, he crossed 

 the Sahara to Lake Chad, passed North- 

 ern Hausaland to the Niger at vSay, and 

 thence reached Timbuktu. Returning 

 northeast through Sokoto to Kukawa, 

 he explored Bornu. Barth 's journeys 

 w^ere of great value, for he not only made 



known to the world the existence and 

 accessibility of hundreds of thousands of 

 square miles of fertile territory, but he 

 also gave in five volumes an enormous 

 amount of geographical information, in 

 which he treated quite thoroughl}' the 

 ethnology of the various tribes of the 

 Central Sudan. His successor, Rohlfs, 

 after exploring Southern Morocco, pene- 

 trated the Sahara to the oases of Tuat 

 and Ghadames, and those of the districts 

 of Fezzan and Tibesti. He then crossed 

 from the Mediterranean to the Guinea 

 coast via Bornu and Dagos, on the Niger, 

 the first European to make the journey. 

 Later (1 873-' 78) he explored the oases 

 in the Libyan Desert. 



The Sahara, instead of being a low^ 

 desert of marine origin, is an elevated 

 plateau, which has been enormously de- 

 nudated by the disintegration of its rocks 

 through temperature changes and the 

 distribution of its dust by hr'gh winds. It 

 is not entirely rainless ; has many fertile 

 oases and onl}^ needs abundant water to 

 produce luxuriant vegetation. 



The first Europeans to cross Africa 

 from east to west north of the equator 

 were Matteucci and Massari, who trav- 

 eled from Suakin via Kordofan, Wadai, 

 and Kano to the Niger. Nachtigal 

 ( 1 869-' 70) made a journej^ from Tripoli 

 via Fezzan to the Libyan Desert, where 

 he explored the remarkable mountain- 

 ous region of Tibesti. Examining the 

 Lake Chad district, he reached Egypt 

 via Wadai and Darfur. 



NIGER AND NILE AN OPEN BOOK 



The mystery of the Niger, long er; 

 roneously supposed to flow through the 

 Sudan to the west, was partly solved by 

 Mungo Park, who, starting from Gam- 

 bia, in his first journey reached Segu, 

 on the Niger. His second expedition 

 (1805) ended in failure. Clappertoii,, 

 renewing the survey, perished, but his 

 faithful assistant, Richard. Lander, defi- 

 nitely solved (1830) the mystery, of the 



