South of Siwa, beyond the shifting yellow sand-hills, there is a vast stretch of desert without a single shred of vegetation which reaches down to the Sudan. Only the first hundred miles has been explored, beyond that is _terra incognita_. The Arabs call this the Devil’s country, and rightly so. In these huge silent spaces one sees incessant mirage, for which the native name is Devil’s water, and frequently “the genii of the storm, urging the rage of whirlwind,” sends a high hurricane of hot stinging sand tearing across the desert, smothering men and beasts in blinding dust, snatching up anything that is loose and bearing it away. “In solitary length the Desert lies, Where Desolation keeps his empty court. No bloom of spring, o’er all the thirsty vast Nor spiry grass is found; but sands instead In sterile hills, and rough rocks rising grey. A land of fears! where visionary forms, Of grisly spectres from air, flood and fire Swarm; and before them speechless Horror stalks. Here, night by night, beneath the starless dusk, The secret hag and sorcerer unblest Their Sabbath hold, and potent spells compose, Spoils of the violated graves——” I once trekked down here in summer-time on the track of some gun-runners who were supposed to be making for Egypt from the west. It is a dreary region, horribly dead and monotonous, consisting of alternate stretches of hard ground covered with shining black pebbles, and white sand-dunes, stretching east and west, where the sand is so soft and powdery that camels and men sink deep into it, and the surface is so hot that one can hardly bear to feel it. There are no tracks or mashrabs, and we were the first party to set up cairns on the hills, wherever there were stones. If one travelled on and on for about a thousand miles one would arrive at Darfur, in the north-west corner of the Sudan. Until the war Darfur was an independent kingdom whose Sultan, Ali Dinar, reigned from his capital El Fasher in a similar manner to the Sultan of Wadai.