[Illustration: A SANDY RIVER-BED, IN THE MOUNTAINS, SHORTLY AFTER RAIN HAS SWEPT DOWN IT NOTE HOW PASSAGE OF CURRENT HAS RIPPLED THE SAND] On the other hand, I noted that places of water—wells, and, particularly, oozing surface springs in river-beds, often salt and chemical bearing, were more numerous in Ahaggar than in Aïr, and where such conditions exist there is also more domestic, garden-plot cultivation, executed chiefly by _Zakummeran_ and _Imrad_ tribes, and not by the haughty nomadic Tuaregs. As a whole, these mountains of the Sahara attract more rain than the desert, on the rare occasions when the rain condescends to fall from the sky. But that advantage is almost momentary, for, owing to the naked, growthless, and soilless slopes, and the quick fall of the intricate network of mountain brooks and river-courses, so soon as rain touches the bare hills it streams down, to be swept away out into estuaries on the desert that drink in water with a thirst that knows no quenching. Nevertheless, a frugal benefit is left behind, for the passing of mountain torrents leaves some moisture in the river-banks, and pools in the best of deep-gullied streams, and in a brief week green vegetation springs to life in thin lines in places, and grows quickly to maturity. And it is this that is the grazing supply of the year—whether browsed over then or in the long, dreary months that follow, when grass and plants, in scattered tussocks, lie hay-dry and uninviting, but are the best that the country has to offer. I noted in Ahaggar that clouds were often in the sky; which I had not remarked in Aïr, or, for that matter, anywhere farther south, except at the season of rains (July-August) in the Western Sudan—rains which sometimes move northwards over parts of the Sahara. It may be that out-thrown influences of the northern hemisphere, despatched from the Mediterranean over the Atlas Mountains, reach southward to about the latitude of Ahaggar. Later on, when marching to the north of the Algerian Sahara, I noted in my diary the _coolness_ of north winds, when they blew, and imagined I sensed a tang of the sea in my nostrils. (Born and reared by the sea, my senses are acutely tuned in that respect.) In conclusion, the Sahara is, in entirety, a vast waste land in its interior; its greater area made up of broken, desolate plains; its features of relief extraordinary mountain-lands of rugged grandeur. Throughout the whole decay appears insistent and sure, and the increase of sand incessant. It has been shown to be a land containing considerable rock surface, and wherever one goes much of such country is disintegrating and crumbling away; thus forming more and more sand, which accumulates, at the whim of the prevailing wind, to bank up and choke out the plant life of the country. In places one may dig down at the roots of shrubs and plants that are dead and find that the old surface of the ground is a foot or so beneath that of to-day. [Diagram]