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 Grant reached Gondokoro in Southern Sudan, where he met Samuel Baker and his "wife". (Her name was Florence von Sass and she had been rescued by Baker from a slave market in Vidin during a hunting trip in Bulgaria.) Speke had expected to meet John Petherick and his wife Katherine at Gondokoro, as they had been sent by the RGS south along the Nile to meet Speke and Grant. However the Pethericks were not there but on a side expedition to trade ivory, as they had run out of funds for their expedition. This caused some hard feelings between Pethrick