<Li> James Frederic Elton (1840--1877) </Li> <Li> Ignatius Knoblecher (1819--1858), explored the White Nile basin </Li> <Li> Alexander Gordon Laing (1793--1826) </Li> <Li> Richard Lemon Lander (1804--1834) </Li>

What role did the geography of sub-saharan africa play in its history