The exploration of Tibesti, Erdi, Borkou, and Ennedi in 1912-1917 : a mission entrusted to the author by the French Institute

At a 1920 Royal Geographical Society meeting, a French lieutenant‑colonel recounts the first years of a daring six‑year expedition across the remote Tibesti, Erdi, Borkou and Ennedi regions of central Africa. The mission was commissioned to test a puzzling hypothesis: that the low‑lying desert plains northeast of Lake Chad might once have drained into the Nile, linking two great river basins. Early observations of unusual sea‑level differences, a trench that traced an ancient valley, and a Nile‑type shrimp in Chad’s waters set the stage for a scientific quest unlike any before.

The explorer’s enthusiasm is rooted in childhood sermons about France’s duty and the legend of early African pioneers such as de Brazza, which sparked a lifelong fascination with the continent’s blank maps. After service in Madagascar and along the Niger, he finally set out in 1912, driven to chart a precise geographical chain from the Niger, through Chad, to the Nile. Listeners are invited to share his first encounters with towering volcanic ranges, nomadic caravans, and the stark beauty of a desert that still held more questions than answers.