Five Weeks in a Balloon the need to release gas or throw ballast overboard to control his altitude, allows very long trips to be taken. This voyage is meant to link together the voyages of Sir Richard Burton and John Hanning Speke in East Africa with those of Heinrich Barth in the regions of the Sahara and Chad. The trip begins in Zanzibar on the east coast, and passes across Lake Victoria, Lake Chad, Agadez, Timbuktu, Djenné and Ségou to St Louis in modern-day Senegal on the west coast. The book describes the unknown interior of Africa near modern-day Central African Republic as a desert,
John Hanning Speke highlands of today's Rwanda and Burundi into the Lake across the Kagera Region of today's Tanzania. Much of Speke's "Journal of the Discovery of the Source of the Nile" is a description of the physical features of Africa's races, in whose condition he found "a strikingly existing proof of the Holy Scriptures." Living alongside the negroes, Speke found a "superior race" of "men who were as unlike as they could be from the common order of the natives" due to their "fine oval faces, large eyes, and high noses, denoting the best blood of Abyssinia" –; that is, Ethiopia. This