the former existence of a lake, the barrier of which was probably near Hererât. I noticed also, at the point where the Wadi Es-Sleh enters the plain of El Gâa, unmistakable signs of an ancient lake. The wadi emerges suddenly from the mountain-range, and a circular depression from thirty to fifty feet deep, with a perfectly level sandy bottom and bounded by nearly vertical gravel cliffs, now marks the bed of a small lake.
The uninhabitability of the peninsula is due to its sterility rather than to its climate. Its sterility is due, I imagine, more to the unequal annual distribution of the water than to its absence, and, should the population warrant it, storage-dams, easily constructed in the narrow granite-walled wadis, would to a great degree remedy this defect. Perhaps at some future day, when a crowded world thrusts its surplus population into regions now hardly regarded as habitable, Arabia Petræa will bloom like a garden. Granite and limestone furnish valuable soil-ingredients, and the climate is not unfavorable to semi-tropical cultivation.
The flora and fauna of the desert have been often described, yet I imagine that much remains to be studied; the variety, beauty, and fragrance of the shrubs and flowers which the traveler meets in the most forbidding and unexpected spots were to my unprepared mind a remarkable feature. In March I gathered dandelions and daisies at Wadi Useit, also "butter and eggs"; in Wadi Tayyibeh, near saline water, spearmint; and in Wadi Feiran, on the hillsides, sorrel.
The oases with their date-palms, tarfa (or tamarisk) yielding manna, seyâl (or acacia) yielding gum arabic, gharkad shrubs, and thickets of tall reeds, are veritable islands of fertility in an ocean of desolation. At the monastery, cypresses, oranges, peaches, and vines are cultivated, although five thousand feet above the sea-level.
Naturalists enumerate a number of large animals that live in the oases of the desert, among them the gazelle, ibex, jackal, and fox. I met with the head of a gazelle and numerous horns of ibexes, and in Wadi Es-Sleh a Bedouin suddenly appeared with two little half-tamed ibexes about fourteen days old; my traveling companion bought them, but they were unable to withstand the novelty of camel-riding, and, though kindly cared for, died within a few days. Their skins were preserved. I noted on the journey a large field-mouse, a small light-yellow snake two and a half feet long, and a peculiar kind of lizard (?). At Assouan I killed an intensely energetic scorpion, and at many places noted chameleons basking in the sun. Of the numerous and curious fish in the Red Sea, I can only say that some of them proved to be excellent food.