A Bechuana may meet a troop of Bakalahari, and domineer over the whole with impunity; but when he meets a Bushman he is fain to adopt a more humble tone, well knowing that if the request for tobacco is refused, the free son of the desert may endeavour to obtain it by a poisoned arrow.
TOWER IN AGADES.
CHAPTER X.
THE SAHARA.
Its uncertain Limits—Caravan Routes—Ephemeral Streams—Oases—Inundations—Luxuriant Vegetation of the Oases contrasted with the surrounding Desert—Harsh contrasts of Light and Shade—Sublimity of the Desert—Feelings of the Traveller while crossing the Desert—Its charms and terrors—Sand-Spouts—The Simoom—The ‘Sea of the Devil’—The Gazelle—Its chase—The Porcupine—Fluctuation of Animal Life according to the Seasons—The Tibbos and the Tuaregs—Their contempt of the sedentary Berbers.
From the Nile to the Senegal, and from the vicinity of Agades or of Timbuctoo to the southern slopes of the Atlas, extends the desert which above all others has been named the Great.
Surpassing the neighbouring Mediterranean at least three times in extent, and partly situated within the tropical zone, partly bordering on its confines, its limits are in many places as undetermined as the depths of its hidden solitudes. No European has ever travelled along its southern boundary, nor is its interior known, except only along a few roads, traced for many a century by the wandering caravans.
In general the desert may be said to extend in breadth from the thirty-ninth to the seventeenth degree of northern latitude; but while in many parts it passes these bounds, in others fruitful districts penetrate far into its bosom, like large peninsulas or promontories jutting into the sea.
Until within the last few years, it was supposed to be a low plain, partly situated even below the level of the ocean; but the journeys of Barth, Overweg, and Vogel have proved it, on the contrary, to be a high table-land, rising 1,000 or 2,000 feet above the sea. Nor is it the uniform sand-plain which former descriptions led one to imagine; for it is frequently traversed by chains of hills, as desolate and wild as the expanse from which they emerge. But the plains also have a different character in various parts: sometimes over a vast extent of country the ground is strewed with blocks of stone or small boulders, no less fatiguing to the traveller than the loose drift sand, which, particularly in its western part (most likely in consequence of the prevailing east winds), covers the dreary waste of the Sahara. Often also the plain is rent by deep chasms, or hollowed into vast basins. In the former, particularly on the northern limits of the desert, the rain descending from the gulleys of the Atlas, sometimes forms streams, which are soon swallowed up by the thirsty sands, or dried by the burning sunbeams. In spite of this short duration, the sudden appearance of these streams is not unfrequently the cause of serious distress to the oases which border the northern limits of the desert.