_Western Ennedi._—It only remained to me to cross the central part of Ennedi in order to have a clear outline of the general physiognomy of the country, thanks to the aid of surveys previously executed on its western borders by several officers who had taken part in military operations in Western Ennedi under the orders of Major Hilaire and Major Colonna de Léca. With this end in view, I marched in the direction of the military post of Fada by Boro and Archeï. For a week our route lay through a maze of sandstone rocks where no track existed, and through which our guides zigzagged from crest to crest with remarkable sureness. Sometimes we made a long _détour_ to cross a wadi near its source; sometimes we marched straight for the obstacle, dropping down steep ledges that inspired little confidence in our animals, or crossing difficult ridges that the camels could only climb after being unloaded. Everywhere were narrow gorges and jagged crests, with here and there a few leagues of easy going in the neighbourhood of the temporary pools that usually marked the convergence of certain important ravines. In this uneven ground with its narrow horizons one pasture-ground succeeded another, but we saw no trace of inhabitants. And yet water was not wanting, whether in natural cisterns or in great pools like that of Kossom Yasko. We skirted on the south the tableland of Basso, higher, according to our guides, and harder to climb than that of Erdébé, but, so far as I could judge at a guess, its height is not likely to be as much as 5000 feet. We took a day’s rest in the excellent pastures of Boro before leaving the central plateau of Ennedi to drop down to the next level, 400 or 500 feet below. Then our way lay along a fine river of white sand, between banks 60 or 80 yards high, where the traces of the last flow of water could be seen 6 or 7 feet up the bank. The coming of the floods is so sudden, and the banks so steep and smooth, that it is dangerous to take that road in the rainy season. No winter passes without some heedless wayfarers being surprised and carried away by the rushing torrent that comes sweeping down the valley with the speed of a galloping horse. After this splendid sand-road came a stretch of rocky going, followed by a zone of waterfalls we had to get round by a march on the plateau. The lower we got the more picturesque the landscape became; the cliffs, gaining in height what we lost in altitude, grew more and more imposing, the crests more jagged, the ridges more often broken by gaps. Isolated peaks appeared here and there, whose pure outlines and bold summits put climbing out of the question. On all sides there rose in the distance rocks, some broad, some slender, but all of the same height and grouped irregularly, so that sometimes, when very close together, they looked like groups of men.