Water was about a quarter of a mile away at the head of a sandy inlet. A bird of good omen swung slowly in the air over it: the White Vulture, that is known to the nomads as _Kargi Mulet_. Tuareg folklore teaches that: “If a traveller is in country that he is not familiar with and sees _Kargi Mulet_ planing slowly to and fro in the sky, it is sure news that water, or people, or game will be found beneath where it flies. Wherefore, if anyone is lost, the sight of this bird is an omen of succour near at hand.” To find permanent open water is very surprising in such surroundings, consequently the conditions under which it exists are of the utmost interest. A few such rock-pools and ancient wells, for the most part separated about five, six, or seven days’ march, afford the only means of obtaining water in the uttermost interior of the Sahara. Tamengouit is on latitude 20°. A chasm, that carries heavy weight of water during rare storms, leads from the distant hills out to the level sand. Just above the mouth it narrows to a long, deep gulch with high walls that completely shut out the sun. It is so narrow that it can be leapt across overhead. Down in the bottom, all along its length, lie deep black waters, inaccessible, because of the cliff walls, except at the mouth and at the top end. One or two specimens, shot while flying overhead, pitched into the chasm and could not be gathered. There is no seepage through the rocks, and the secret of the water’s permanent existence is surely in the fact that the all-absorbing sun cannot reach it. Gloomy and cool, the chasm interior is as a thick-walled tank that no influence of the elements can penetrate. Remarkable in itself, this rock basin is equally remarkable on account of bird life. In camp on the first night I heard Sandgrouse calling at dusk, and in the night; and knew they were flighting out of the clear sky, from unknown feeding grounds, to slake their thirst in the still chasm. Their presence was certain assurance of water known to the wild, and I turned to sleep expectant of a busy day on the morrow. And I was not disappointed. Early morning found me at the pool, where a few Coronated Sandgrouse and Barred Sandgrouse still remained from the flocks of overnight. Otherwise all was yet quiet, but I could foresee change whenever the morning feeding time was over, for there were plenty of feathers and toe-prints at the water’s edge, to tell that numerous birds were in the habit of drinking there. [Illustration: TWO MALE OSTRICHES COLLECTED ON THE SOUTHERN SHORES OF THE SAHARA] I spent the time searching for Nightjars among the rocky flats beyond the chasm. Those nocturnal birds are very difficult to find, because of their perfect protective colouring among the rocks where they hide during the day, and their habit of remaining still until almost trodden upon. My search proved fruitless, and I returned to the water.