A sandy heath of various levels, in some places naked and bare, but much more frequently covered with an odoriferous plant, which the Arabs call the Shé, and which, though far superior in fragrance, has at least a remote resemblance to the wild thyme of Europe, constitutes the general appearance of the Desart. The exceptions, however, are interesting and important: for besides the diversity that arises from the different shrubs, which are often scantily intermixed with the Shé, and of which the thorny plant that forms the harsh food of the camel appears to be the most common, an essential variation is furnished by the comparative fertility of some particular districts, and by the total barrenness of others. [Sidenote: Imhammed and Ben Alli.] In some portions of the general wilderness, thousands of sheep, and goats, and cows, are seen to pasture; while in others nothing is presented to the eye but desolate hills of shifting sand. [Sidenote: Imhammed.] To the last of these the name of _Desarts without Water_ is emphatically given; a name that conveys to an Arab ear the fearful idea of an intense and suffocating heat, of the total absence of vegetable life, and of the hazard of a dreadful death. For though the movement of the shifting sands is not so rapid as to endanger the safety of the caravan, yet as the scorching heat of the sun-beams, confined and reflected by the hills of sand, hourly diminishes the store of water, and as the breadth of several of those desarts is that of a ten days journey, the hazard of perishing with thirst is sometimes fatally experienced. [Sidenote: Imhammed.] All means of ascertaining the rout by land-marks, the usual guides in other parts of the wilderness, are here destroyed by the varying forms and shifting position of the hills; but from anxious observation and continued practice, the camel-drivers acquire a sufficient knowledge of the bearings of the sun and stars to direct them in their way. Such are the expedients by which the difficulties of the Desart are in general overcome: those which are presented by the broad current of the impetuous Niger, though much more easily, are not so frequently surmounted. [Sidenote: Imhammed.] [Sidenote: Imhammed and Ben Alli.] [Sidenote: Imhammed.] [Sidenote: Imhammed.]