source, and in 1869 Winwood Reade crossed the Joliba itself within 110 miles from its origin. Ten years later, Zweifel and Moustier came within sight of the Tembikundu hill, the fountain-head of the sacred river; but the spirit of the waters, represented by a suspicious high-priest, barred their farther advance. Of the upper course the best known section is naturally that which forms the present boundary of French Sudan for a distance of about 300 miles between Falaba and Sansandig. But even here the side branches and eastern affluents have been traced on the maps only from the reports of native traders. Below Timbuktu the
course of the stream has been more accurately determined by Barth's survey in 1854; but the space of about 165 miles, between the towns of Sai and Gamba, at the Sokoto confluence, has never been revisited by any European since Mungo Park's expedition.
All the lower reaches, except some of the secondary branches of the delta, are well known, having been ascended from the sea by Laird in 1832 and Oldfield in 1834, and since then by numerous other explorers, including Joseph Thomson, who, in spite of many obstacles, made his way from the coast to Sokoto and back
