M. Trémaux observed this curious phenomenon in the ravines of Korosko, but it probably occurs elsewhere under similar conditions. On closely examining the carcasses which he met at every step, he was astonished to find them covered with their skin, and presenting still their natural forms, as if the animals had been stuffed or embalmed. He readily distinguished horses, oxen, asses, camels. He observed with no less surprise that these corpses exhaled no odour. They had been dried by the heat before decomposition could commence its frightful work. The skin had hardened; the muscles and internal organs had been reduced into dust and gradually blown away by the wind through the yawning apertures at the two extremities of the body. There remained nothing more, literally, but skin and bone.
“This skin had such a consistency,” says our author, “such a degree of solidity, that all my efforts to split it were without result. The heaviest stones which I could raise rebounded upon their carcasses with a loud noise, but did not pierce them. If a man dies while a caravan is on its march, he is buried in the sand. I have had no opportunity of examining whether the desert-heat produces the same effect upon his body as upon the corpses of the animals just mentioned; but it ought not to be so, since the human skin has not the same consistency.”
On issuing from these gorges, we enter upon the Desert proper by a sandy plain which the Djellahs have named the “River without Water,” and which, very low at first, slowly rises into a plateau of very slight elevation, intersected by some veins of a sandstone similar to that of the conical mountains. Then the plain declines anew, and we emerge upon the Sea of Sand, where the pulverized sandstone alternates with fields of rotted or broken pebbles, and mounds of porphyry and granite. At the foot of one of these mounds, the Tallat-el-Guindé, flourish a few wretched vegetables, among others some gum-trees and doum-palms. The latter trees are also found in solitary mournfulness scattered about the plain. Otherwise the Desert of Korosko is wholly deprived of vegetable life, of
“The glory in the grass, and the splendour in the flower.”
As for water, it must needs be content with that of a few brackish wells, grouped, about twelve in number, at a spot called El-Mourath. It is there only that the caravans can fill their ill-tanned leather-bottles, in which the already nauseating liquid grows hot, and quickly becomes putrid. Its stench and its taste are then so disgustful that the very camels reject it several times before they can constrain themselves to drink of it.
The Desert of Bahiouda, situated in about the same latitude as that of Korosko, but on the other bank of the Nile, is of a less absolute aridity and nakedness. Water is more abundant and less brackish; vegetation is less scanty; and one meets on every side with giraffes, gazelles, wild cattle, and even, it is said, with lions and elephants. Great numbers of reptiles, lizards, serpents, and tortoises inhabit the sand and the crevices of the rocks.
South of the above-named Deserts, towards 17° N. lat., is placed the limit of the Rainless District. Under the 18th parallel the rains do not last above one or two months in the year, and in some years are absolutely wanting; but when they do fall, it is generally in impetuous torrents. As we advance towards the Equator they become more regular, and last for longer periods. According to Humboldt, the average yearly rainfall in 19° N. lat. measures 80 inches; under the equator, 96 inches. In these tropical climes the year is divided into two seasons—one of excessive drought, and one of excessive rain. During the former, the sky is ever cloudless; during the latter, completely overcast.
There are, in fact, two rainless belts or districts, one on each side of the Equator. In the old world, the northern belt commences on the west side of Africa; includes the Sahara between 16° and 28° of latitude; and narrowing as it extends easterly, comprises on the banks of the Nile from 19° to 27°. It also embraces the low coast; and portions of the interior of Arabia; passes through Beloochistan to the base of the Himalayas, and terminates with the rainless tableland of Thibet. The southern district occurs north of the Gareep or Orange River in South Africa, and includes wide tracts in Australia, and a narrow belt in South America.