We now enter the Desert of Erosion, a mass of mountainous highlands; of ridges, peaks, and cols, intersected and, as it were, gashed by ravines where roll the winter torrents and the rivers which the heats of summer dry up, and which, hollowing and gnawing into the stony soil, spread themselves over the valleys and awake a transitory vegetation. The erosive action of the waters is, then, the special characteristic of this part of the desert, which the Arabs call Kifar, or “the abandoned country.” Most of the streams which water it have their sources in Mounts Aurès and Zibans, which form its northern boundary. They have excavated wide intermingling furrows, whose intervening spaces are occupied by gypseous plateaux. The formations of less resisting power, the marls, clays, and sands, have been washed away.
The waters, whether proceeding from rain, or the melting of the snows on the loftiest peaks, are very pure at first, and roll in deep beds with vertical sides; when they reach the plains, their channels grow wider and shallower. In the wet season, the floods burst the banks, and overflowing, carry down immense quantities of rolled pebbles, which are distributed over an extensive area; in ordinary weather they are reduced to thin threads of silver, which, on arriving in the desert, vanish completely. You must excavate the soil to obtain a supply of water, and when found, it is brackish. Frequently the beds unite, forming basins of greater or less extent and depth, which fill themselves at the close of the winter floods, and a few of which preserve, even in the winter season, a certain quantity of water. Elsewhere, the soil is only humid, thanks to the abundance of salt, which retains the moisture. In such places numerous slimy marshes occur, where the traveller may not adventure without peril. But in general the surface is dry, cracked, cloven, and completely parched.
The Desert of Erosion is not completely inhabited. At intervals you meet with a few squalid villages, and a multitude of camel’s-skin tents are scattered like black spots over the yellow or grayish plains, on the borders of the chotts or scanty water-courses. Herds of goats and flocks of sheep wander in the valleys, browsing on the rare short grass. Columns of smoke arise from the Arab bivouacs, and the women of the Sahara group themselves around the wells and springs to fill the water-bags with which they load their asses.
When, from the summit of the rocks which fence round and bristle over the Desert of Erosion, we perceive for the first time the Desert of Sand, the impression is very similar to that which we derive from the sight of ocean. M. Martins had already become sensible of this peculiar effect when, from the Col de Sfa, he had gazed down upon the Desert of the Plateaux. “A grand circular arch,” he says, “extended before us, bounding a violet surface, smooth as the sea, and blending at the horizon with the azure of heaven; it was the Sahara. The arc eastward rested against the chain of the Aurès; westward, against that of the Zibans, some of whose offshoots, in the neighbourhood of Biskra, arose like reefs upon that sea which seemed to have been frozen suddenly into immobility. The actual sea ever trembles and shivers on the surface; a light wavering, imperceptible to the eye, propels towards the shore the expiring wave, fringed with a border of foam. Here, nothing like this may be seen; it is a motionless, a congealed sea, or, rather, it is the smooth bed of a sea whose waters have disappeared. Science teaches us that such is the fact; and now as ever the expression of the reality is more picturesque, more eloquent than all the comparisons created by the imagination.”[56]
An eminent French artist, M. Fromentin, whose skill with the pen equals his talent with the brush, has also painted this “congealed sea” in grand and poetic language. “The first impression,” he says, “produced by this glowing lifeless picture, composed of the sun, space, and solitude, is keen, and cannot be compared to any other. Little by little, however, the eye grows accustomed to the grandeur of the lines, to the emptiness of space, to the denudation of the earth; and if anything can still astonish, it is that one becomes sensible to effects which change so little, and is so powerfully affected by spectacles in reality of the simplest character.”[57]
I must also enumerate among the “artists in words” who have painted the wonders of the Sahara, General Daumas, not one of the least distinguished of the Franco-Algerine warriors. He describes it in the following language:—“It is a naked and barren immensity,—this sea of sand, whose eternal waves, agitated to-day by the choub, will to-morrow be heaped up immovable, and which are slowly furrowed by those fleets called caravans.”
General Daumas, it is evident, confines himself to the scientific realism, which M. Martins prefers to the glowing and inexact imagery of the poets, and conveys in a few words an accurate yet very picturesque idea of that arid sea, where the wind stirs up rolling waves of sand instead of foaming billows, and which the Arabs call Falat. I shall place before the reader, however, the description given by M. Martins himself, for it represents both the ensemble and the details of the picture.
“If the Desert of the Plateaux,” he says,[58] “be the image of a sea suddenly fixed during a level calm, the Desert of Sand represents to us a sea which may have been solidified during a violent tempest. The Dunes, or sand-hills, like waves, rise one behind another even to the limits of the horizon, separated by narrow valleys which represent the depressions of the great billows of the ocean, all whose various aspects they simulate. Sometimes they narrow themselves into keen-edged crests, or shoot upwards in pyramids, or swell into cylindrical domes. Seen from a distance, these Dunes also remind us at times of the appearances of the névé (or granulated snow) in the amphitheatres and on the ridges which lie contiguous to the loftiest Alpine summits. Their colours still further enhance the illusion. Moulded by the winds, the burning sands of the desert assume the same forms as the névés of the glaciers.”