Dar Guimer is hardly more than a gently undulating plain of somewhat uniform appearance, 100 miles across from east to west, and 20 from north to south. The inhabitants, few in number, if I may accept the accounts given me, seem less inclined to tillage than to cattle-raising. The soil is usually clayey, very marshy from the end of July to December, but almost completely waterless from April to July. The valleys come down fanwise from the tablelands of Tama on the west, of Zagawa on the north, and northern Dar Four on the east. They meet on a level with the Djebel Kichkich (Hadjer Moull) to form the Wadi Kadja, one of the parent branches of the Bahr-Salamat, which is one of the most important valleys on the right bank of the Shari, the main affluent of the Chad. During the morning of June 25 we reached the southern limit of Dar Guimer at the wells of Taziriba; only 3 yards deep and flowing abundantly at all seasons, they were situated in a valley where there are no trees of any size, but an abundant growth of scrub. The wells, usually silted up, had been dug out afresh a few days previously, on the occasion of the Sultan Idriss’ visit to Dar Four. Having thus been able to water our camels and renew our own supply, we left the territory of Guimer the same evening, to go and sleep half a score of miles further on. _Between Guimer and Dar Four._—It is interesting to notice that the tribes whose territories separate Wadai from Dar Four (Massalit, Tama, and Guimer) have always left a wide belt of uninhabited country between themselves and Dar Four. At some points its width exceeds 100 miles, while no similar solution of continuity exists between them and Wadai. It should not be concluded, as is sometimes done, that these territories are desert-like in character, for they are watered every year by the summer rains and covered with an abundant vegetation, for the most part thorny and stunted, it is true. These lands are not incapable even of settled habitation, for it would suffice to bore a few wells, around each of which men could take up their quarters in permanence, with fields of grain and cotton and pasturage for cattle. Such unpeopled regions are common in Central Africa, and each of them constitutes a neutral zone, a sort of “no man’s land” that separates the territories of two hostile tribes.