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HE Sandy Deserts may with equal, nay, with greater accuracy, be entitled Salt Deserts, Rainless Deserts, Seas of Sand; for they present at one and the same time all these characters, and the three last, though less generally known than the first, are the most essential.

The soil is generally covered with a thick stratum of sand; but in several places it also exhibits great walls of rock, and in others masses of rolled or shattered pebbles. The subsoil is nearly always of a gypseous or calcareous nature, rarely clayey; wherever it is porous and permeable, it is impregnated with salt, which rises to the surface, or is held in solution in the subterranean basins of water, the thermal springs, the ponds, and the lakes. The saline efflorescences of the deserts of Persia and Oriental Asia not only suffice for the wants of the inhabitants, but supply the great Asiatic caravans with their principal article of exportation.

The atmosphere of the Deserts is not less dry than their sands and rocks. The sky wears a perennial azure, more or less veiled in haze, or rather spotted with a few clouds. Johnstone represents them, in his admirable “Physical Atlas,” by two white unequal bands, characterised as “Rainless Districts.” Of these the larger occupies all the northern region of Africa, and the greater portion of Arabia, Syria, Persia, and Beloochistan, embracing an area of 80° of longitude over 17° of latitude. The other extends over the table-lands of Thibet and the Gobi. It is in form an irregular ellipsis, obliquely inclined from south-west to north-east. Its length is about 1100 leagues; its width, 450. From the former it is only separated by a narrow belt. In the region marked by these two species rain is an extraordinary phenomenon; several years will pass without the clouds shedding a single drop of water. This permanent, and nearly absolute, aridity, establishes a very marked difference between the Deserts properly so called, and the Landes, Steppes, and Prairies, condemned as these are during the hot season to a deadly dryness, but in winter inundated with rain or covered with snow; and in spring converted into immense marshes, where an exuberant vegetation makes its appearance, frequently capable of resisting the action of the summer sun and the withering winds.

In the Rainless Districts vegetation is a nullity; it becomes reduced to a very small number of saline plants and dwarf bushes, nourished by the brackish waters which, the soil conceals. Finally, the desert region may not only be compared to a sea in its aspect and immensity, but it is a true sea, or at least the bed of an ancient sea, which formerly communicated, and, perhaps, was confounded with the Mediterranean, and whose drying up, though still incomplete, took place at a recent geological epoch. We may reasonably conclude that, owing to a series of gradual upheavals, this sea was at first broken up into vast lagoons; that most of these successively disappeared, but not without leaving some certain evidences of the primitive submersion of the continent. “If we might hazard a conjecture,” says a recent writer,[41] “it would be that the same convulsions and upheavals which at the close of the tertiary epoch indented the southern coasts of Europe, at the same time drained the ocean which hitherto had rolled over the plains of the Sahara, and submerged the low-lying lands, which probably united the Canaries and Madeira to the mainland.” To a similar cause must be attributed the existence of the subterranean waters, springs, ponds, and salt lakes, of which I have already spoken, and of the inland seas—the Caspian, the Sea of Aral, and the Dead Sea; while the Black Sea and its offshoots, the Sea of Azov and the Sea of Marmora, must have had the same origin. I shall discuss this subject further when describing the Great Sahara.

In Eastern and Central Asia, the Sandy or Salt Deserts alternate with the Steppes, and with lands susceptible of a certain amount of cultivation. The vast region which geographers designate the Great Gobi, or the Shamo, is intersected by many grassy Steppes and even by fertile fields, where the sedentary Mongols, and especially the Artons, yearly sow and gather hemp, millet, and buckwheat. The sombre picture of “a barren plain of shifting sand blown into high ridges where the summer sun is scorching, no rain falls, and when thick fog occurs it is only the precursor of fierce winds,”[42] is true only of special districts, such as the Han-hai, or “Dry Sea,” or the Desert of Sarkha. There, for instance, we meet with no other vegetable than the salsolæ, or salt-worts, which flourish around the small saline pools. Of these pools, when seen from a distance, Mr. Atkinson notices a remarkable characteristic: the salt crystals which accrete upon their banks frequently reflect the orange or crimson hues of flowers, and resemble glowing rubies set in a rich mounting.

As we advance in a south-easterly direction, we find the features of the desert region more prominently marked.

Immense plains of sand, with a bare and brackish surface, called Bejaban, traverse the whole of Persia, from the Caspian Sea to the Indus. They comprise the Deserts of Kerusan, Seistan, Beloochistan, and Mekran, rich in salts with a basis of soda. “The coasts of the Persian Gulf,” as Mrs. Somerville remarks, “are burning hot sandy solitudes, so completely barren, that the country from Bassora to the Indus, a distance of 1200 miles, is nearly a sterile waste. Three-tenths of Persia is a desert, and the tableland is nearly a wide scene of desolation. A great salt-desert occupies 27,000 square miles between Irak and Khorasan, of which the soil is a stiff clay, covered with efflorescence of common salt and nitre, often an inch thick, varied only by a few saline plants and patches of verdure in the hollows. This dreary waste joins the large sandy and equally dreary desert of Kerman. Khelat, the capital of Beloochistan, is 7000 feet above the level of the sea; round it there is cultivation, but the greater part of that country is a lifeless plain, over which the brick-red sand is drifted by the north wind into ridges like the waves of the sea, often twelve feet high, without a vestige of vegetation. The blast of the desert, whose hot and pestilential breath is fatal to man and animals, renders these dismal sands impassable at certain seasons.”

The Desert of Mekran is separated from that of Moultan by the Indus. That which lies to the east of Kom, in the centre of Persia, is more than sixty leagues in extent. Of Persia, M. Forgues observes that the actual reality differs strangely from those glowing eastern landscapes which poets and romancists love to paint. Even in those provinces where the winter rains encourage the growth of vegetation, the scene would hardly remind the traveller of