74 NORTH-WEST AFRICA. also so brackish that strangers find it very unpalatable. In several places it rises to the surface, spreading out in sebkhas or swamps, which are usually fringed by a crystalline zone of salt. The Ilofro, with its eastern prolongation, the Sherkiya, lies south of the last great oasis in Fezzan. Along the route towards the plateau, 2,500 feet high, which separates this region from the Tibbu domain, caravans meet nothing but a few wells and the two small oases of Gatrodn and Tejerri. Eastwards, in the direction of Kufra, the desert is even more dreary than towards the south. Serirs, dunes, saline depressions follow in succession for a space of over 120 miles before the traveller reaches a first oasis, that of AVau-el-Kebir, or, " the Great Wau,", which was unknown to geographers before the journey of Beurmann in 1862. It was occupied by a Negroid Tibbu population down to the year 1841, when they were driven out by marauding Arab tribes, who made it the centre of their raiding expeditions. The Tibbus attempted in vain to recover this oasis, although the conquering tribe was expelled in its turn, and at the time of Beurmann's visit Wau was held by members of the Senusiya brotherhood, who, being all celibates, allowed no women to reside in the place. Beurmann was informed that at a distance of three days' march westwards there was another oasis, known by the name of Wau-es-Serir, " the little "VVau," or Wau-Namus, " Mosquito Wau ; " but no one in the district was able to show him the route to follow, the only person acquainted with the oasis having recently died at an advanced age. This lost depression is the same that was rediscovered in the year 1876 by the Arab Mohammed Tarhoni, aided by a few voluntary explorers from Zella. Unlike Great Wau, it is uninhabited, although numerous potherbs and palm groves cleared of their undergrowth show that until recently it supported a small population, probably of Tibbu stock. Besides date-palms, its flora comprises acacias and tiiraarisks, as well as shrubs of smaller growth. In the rocks is found a deposit of " fine yellow sulphur," while a small lake in the centre of the oases accounts for the swarms of winged insects, whence it takes its name. The former inhabitants had settled on " a very high mountain " above the lake and the clouds of mosquitoes. According to local tradition, there exists to the south-east another oasis, the Wau-IIarir, a valley clothed with a rich vegetation, and inhabited by a large number of animals, such as moufUons, gazelles, and antelopes, which have not yet learnt to fear man, and allow themselves to be attacked and speared. Camels which have lapsed into the wild state are also said to herd beneath the shade of the palms along the banks of the streamlets watering this mysterious oasis. Climate of Fezzan. Lying under a more southern latitude than Tripolitana, properly so called, Fezzan has naturally a higher temperature, ranging from 81° to 83*^ F. Never- theless the cold is more intense, both on account of its greater distance from the sea, which always exercises a moderating influence on climates, and also in consequence of the greater purity of the atmosphere causing at night a free
