42 NOETH-WEST AFRICA. surface is here and there broken by a few volcanic heights, which, however, do not form a mountain range, as is usually represented on the maps. North-eastwards another Jebel Msid, also highly venerated and crowned with a zawya or moslom monastery, limits the Tar-hona plain on the one hand and on the other the Bondara and Mesellata hills, whose spurs terminate on the sea- coast. One of these advanced eminences, whose summit is disposed in three distinct crests, Barth is disposed to identify with the mountain of the Three Graces mentioned by Herodotus, who, however, places it much farther inland. Hydrographic System. Although more than half the size of France, Tripolitana, properly so-called, has not a single perennial stream. But during the rainy season superb cascades are seen tumbling down the rocky sides of Ghurian and Yefren into the lower gorges, •and the muddy waters are frequently copious enough to force their way seawards through the sand accumulated in their beds. Barth reports, on the authority of the natives, that in the year 1806 the Wady-el-Ghasas, flowing from the Jebel Yefren, united with the other torrents of the valley in a powerful stream which reached the coast across the Zonzur palm-groves west of Tripoli, and discoloured the sea with its alluvia for 120 miles, as fur as the island of Jerba. Most of the watercourses have broad channels confined between high banks, a l)roof of the large volume sent down during the floods. Nevertheless travellers usually take the winding bods of these wadies when their route lies in the same direction, and except in the rainy season they have little occasion to regret the ruined state of the Roman bridges met here and there along the more frequented tracks. / Far more useful than the restoration of these bridges would be that of the dams and dykes, which retain the temporary waters of the inundations at the outlets of the upland valleys. At the foot of tKe Jebel Ghurian, Barth saw one of these reservoirs, of Arab construction, whose ruined ramparts are now traversed by the caravan route. The only receptacles at present known to the people of Tripolitana are the maj/ens, or stone cisterns, whose gates are carefully kept under lock and key for the drv season. In several districts the art is also understood of excavating: the so-called fogarats, or underground galleries, in which the fluid is collected, and which communicate with the surface through wells sunk at intervals in the ground. These galleries are similar to the knnafs met in the arid districts of Persia and Afghanistan. Amongst the "extinct" rivers which formerly rolled down considerable volumes, but whose beds have now for most of the year tg be excavated for a little brackish fluid, there are several whose course has been completely effaced before reaching the seaward area of drainage. On the Mediterranean slope of Tripolitana all the wadies, whatever be the quantity of water flooding their channels after sudden downpours or protracted rains, reach the sea, or at least the sebkhas on the coast. Some of them have even vast basins, in comparison with which those of the Italian
