The Sultan of Asoudee has detained many of En-Noor's young people, to protect the country in case there be any troubles with the Kalfadaï. Several pieces of scoria, or lava, were found on the road, showing a district here once to have had active volcanoes. The granite begins to disappear, to be replaced by sandstone. This sandstone, generally, according to Overweg, forms plateaux; whereas granite is found in rocks and ridges in the midst of valleys. _28th._--We started early. The camels move on at the beginning of their day's work to the beating of the _kanga_, or drum. We have two or three drums, but the drummers have little skill, and the beating is always the same monotonous sound. Our course varied from S.E. to S.W., but lay always southward, through shallow valleys, or low, indented, or scooped-out plains; the whole country being what the people call _hamadah_, or plateau. All the large trees have disappeared with the doom-palm. Nevertheless there are everywhere the marks of water. Yet the rain cannot fall here so much as in the mountainous regions which we have left behind, for it is high ground only which brings down the rain in Africa; except, indeed, near the equator. As yesterday, the sand and soft earth are covered with the footmarks of gazelles, ostriches, the habara, and even the giraffe. The people, in fact, say we shall see the giraffe before we arrive at Damerghou. But of these animals, who have left thus the impression of their feet on the sand, we saw not one. Indeed it is quite a matter of luck to fall in with animals in the desert. I have seen but very few. My colleagues have both encountered lions and monkeys, neither of which have I seen. We have come to-day seven hours and a-half, a very good march for En-Noor. The nights are cold enough; there is also a fresh breeze, generally from north-east, every day: nevertheless, the sun burns hot. The sky has always now a few clouds, and the atmosphere is a little thick and misty. We have with us various queer characters; amongst the rest, a fellow who boasts of his having killed many people with poisoned arrows. When I come near him I always attack him, not, indeed, with his favourite weapon, but with irony. I tell him, "Ah! poisoned arrows kill many people.--What matters it?--There is no God" (looking up, and saying _Babo Allah!_) This has had its effect once or twice, and he has confessed it is not so very fine to kill people with poisoned arrows.