The horned viper (vipera cerastes) is thus named on account of the two horns or protuberances on its forehead, which give it a physiognomy more hideous, perhaps, than that of any of its congeners. It attains the length of two to three feet. Its head is depressed, very obtuse, swollen behind the eyes, and, so to speak, truncated in front. Its body, cased in shells of a tawny-like yellow, marked with brown spots, blends curiously with the sand, half-buried in which it lurks to surprise its prey or escape from its enemies. The cerastes frequents the deserts of Lybia, Arabia, the Sahara, and the valley of the Nile. Its bite is exceedingly dangerous.
The varans, or monitors, called also tupinambis by the ancient naturalists, form a genus represented in tropical climes by several species of great size. English writers commonly designate them monitors, the French sauvegardes, because they frequent the haunts of crocodiles and alligators, and give warning of their approach by a whistling sound. Two species belong to Africa: one, aquatic, the varan of the Nile (varanus dracæna); the other, sand-burrowing, the varan of the Desert (varanus sunius, or arenarius), called by the Arabs onaran-el-ard. Their usual size is from three feet to three feet four inches. The varan of the Nile wears an armour of alternately green and black scales. Its congener exhibits a mixture of brown and yellow, more suitable to its sandy lairs. It is rare in the Sahara, but common enough in the deserts of Egypt, Syria, and Nubia.
Poor as may be the Fauna of the Desert, there is yet cause enough for astonishment that the species which compose it, especially the herbivora, should be able to find subsistence in these seas of sand, where they can find but a few saline plants scattered at rare intervals, and where fresh water is almost wholly wanting. It is, however, well known now-a-days that the wilderness provides its denizens with an aliment, which is sometimes very abundant, suitable for man, the camel, and the beasts, and is considered identical by many authorities with the manna of the Bible.[75] This substance is a cryptogamous vegetable, variously christened lichen esculentus (Acharius), lecanora esculenta (Pallas), luttarut (by the Arabs), and vasseh-el-ard, or “earth-dung” (by the Algerines). It sometimes forms on the sand, in the morning, a layer one or two inches in thickness, and appears to have dropped from heaven, or to have sprung spontaneously from the soil, during the night. It is probable that its spores, transported by the wind, are developed by the humidity which is condensed through the nocturnal coldness.
A shower of this lichen was observed, in April 1846, in the Russian government of Wilna. It covered the soil for three or four inches in depth, and the inhabitants lived upon it for several days. Its form is that of a small, anfractuous, rounded grain, about the size of a pea, externally of a gray colour, but white and farinaceous within. Its taste is weak, amygdalaceous, with a faint, mushroom-like aroma. Boiled in water, it swells, becomes gelatinous, and may be served up in various ways. In the Sahara, as well as in Arabia, it adheres to any foreign body. Cattle feed upon it eagerly. It certainly facilitates digestion, and contains all the assimilating principles which form the constituents of the wholesomest vegetable food. Such as it is, the lichen esculentus is an inestimable boon to the wandering tribes of the Desert, who would perish of hunger in years of famine but for its heaven-sent nutriment.
CHAPTER VII.
THE MEN OF THE DESERT.
WHEN I use the terms “Men of the Desert,” “Populations of the Desert,” evidently I must not be understood to employ them in their absolute sense. Man, no more than that other so-called “lord of animals”—the lion, makes a voluntary sojourn in countries where game, verdure, and fresh water are wanting. The peoples whom we entitle “Inhabitants of the Desert” are then, in reality, those who dwell upon its borders or in its oases, but whom the necessity of traversing and frequently abiding in it has familiarized with its gloom and its peril, as a similar necessity has familiarized the mariner with the ocean. We have seen, however, that some pastoral tribes pitch their tents and pasture their flocks in those districts where vegetation is favoured and cherished by a supply of rain or subterranean waters, and which should more accurately be designated as Steppes than Deserts. Some authorities have, indeed, affixed the name of “the Saharan Steppe” to the region of high table-lands which lies at the base of the Atlas range.
Other groups, who are partly shepherds and partly hunters, inhabit, in the Southern and Western Sahara, those plateaux where ostriches, gazelles, and hares abound. The more peaceful and industrious tribes occupy the oases. As for those who encamp or habitually wander in the Sandy Desert—where all cultivation is impossible, where the herds can obtain but an insufficient pasture, where game very seldom shows itself-the reader will suppose that they can only subsist by plundering or ransoming the caravans. These are the rovers, the pirates of the Sea of Sand. There are “land-rats,” Shakspeare tells us, as well as “water-rats.” Others, again, there are who seem convinced that “honesty is the best policy,” who give themselves up exclusively to commercial transactions, and act as agents and intermediaries between nations separated from one another by leagues of rock and sand, for the exchange of their respective products. It might be said of these that they discharged a useful and honourable function, if the purchase and sale of slaves were not the most ordinary, and unfortunately the most lucrative, of their operations.