The chief Asiatic deserts are in Persia and Arabia, the former of which countries contains three of considerable extent and celebrity. The first of these commences on the east of the Tigris, in latitude thirty-three, and extends to the north of Shuster. The second reaches from the vicinity of Korn very nearly to the Zurra, in a line, from east to west, of about four hundred English miles, and from north to south, of about two hundred and fifty. In the latter direction it joins the great desert of Kerman, which, alone, extends over a tract of three hundred and fifty miles. The two may, therefore, be considered as forming one common desert, stretching north-west and south-east, over a space of about seven hundred miles; thus intersecting this wide empire into two nearly equal portions. This vast region is impregnated with niter and other salts, which taint the neighboring lakes and rivers, and has, on that account, been denominated the Great Saline Desert.

ARABIAN DESERTS.

The sandy deserts of Arabia form one of the most striking objects of that country. From the hills of Omon, which appear to be a continuation of those on the other side of the Persian gulf, as far as Mecca, the greater part of Negad is one prodigious desert, interrupted, toward the frontiers of Hejaz and Yemen, or Arabia Felix, by Kirge, containing the district of Sursa, and several oases, or fertile spots. The north-west part of Negad presents almost a continued desert, and is considered as a prolongation of the one above mentioned.

The Beled el Haram, or Holy Land of Islam, of which Mecca is the capital, is comprehended between the Red sea, and an irregular line which, commencing at Arabog, about sixty miles to the north of Djedda, forms a bend from the north-east to the south-east, in passing by Yelemlem, two days’ journey to the north-east of Mecca. It thence continues to Karna, nearly seventy miles to the east of the same place, and twenty-four miles to the west of Taif, which is without the limit of the Holy Land; after which, turning to the south-west, it passes by Drataerk, and terminates at Mehherma upon the coast, at the port named Almarsa Ibrahim, about ninety miles to the south-east of Djedda.

It therefore appears that the holy land is about one hundred and seventy miles in length, from the north-west to the south-east, and eighty-four miles in breadth, from the north-east to the south-west; which space is comprehended in that part of Arabia known by the name of El[El] Hedjeaz, or the Land of Pilgrimage, and includes the cities of Medina[Medina] and Taif. It has not any river; and the only water to be found, is that of some inconsiderable springs, which are not numerous, and the brackish water obtained from the deep wells. Thus it is a real desert. It is at Mecca and Medina alone, that cisterns have been wrought to preserve the rain-water; on which account, a garden is very rarely to be seen throughout this vast territory. The plains are composed either of sand, or barren earth, entirely abandoned; and, as the inhabitants do not, in any part of the country, sow any description of grain, they are supplied with flour, &c., from upper Egypt, Yemen and India.

AFRICAN DESERTS.

The most striking feature of Africa consists of the immense deserts which pervade its surface, and which are supposed to comprise the one-half of its whole extent. The chief of these is, by way of eminence, called Sahara, or the Desert. It stretches from the shores of the Atlantic, with few interruptions, to the confines of Egypt, a space of more than forty-five degrees, or about three thousand miles, by a breadth of twelve degrees, or about nine hundred miles; its whole extent being two-thirds as large as that of the United States. It is one prodigious expanse of red sand, and sandstone rock, of the granulations of which the red sand consists. It is, in truth, an empire of sand which seems to defy every exertion of human power or industry, although it is interspersed with various islands, and fertile and cultivated spots of different sizes, where water collects in springs or pools, around which vegetation springs up. These places, which present a delightful contrast to the surrounding sterility, and cheer the eye of the weary traveler, are called oases. Fezzan, or Fessan, is the chief of those which have been hitherto explored.

Nearly in the center of the southern line of this sandy ocean, and about midway between the Mediterranean sea and the coast of Guinea, rise the walls of Timbuctoo, a city which constitutes the great mart for the commerce of all the interior of Africa. To maintain this commerce is the laborious work of the akkabaars, or caravans, which cross this enormous desert from almost every part of the African coast. The mode in which it is traversed is highly curious. The caravans consist of several hundred loaded camels, accompanied by the Arabs who let them out to the merchants for the transportation of their goods. During their route, they are often exposed to the attacks of the roving Arabs of Sahara, who generally commit their depredations on the approach to the confines of the desert. In this tiresome journey, the caravans do not proceed to the place of their destination, in a direct line across the trackless desert, but turn occasionally eastward or westward, according to the situation of the oases of which we have spoken, which are interspersed in various parts of the Sahara, like islands in the ocean. These serve as watering-places to the men, as well as to feed, refresh and replenish the hardy and patient camel. At each of these cultivated spots, the caravan sojourns several days, and then proceeds on its journey, until it reaches another spot of the same description. In the intermediate journeys, the hot winds, denominated shume, or simoom, are often so violent and penetrating, as considerably, if not entirely, to exhale the water carried in skins by the camels for the use of the passengers and drivers. On these occasions, it is affirmed by the Arabs, five hundred dollars have been frequently given for a draught of water, and that ten or twenty dollars are often paid, when a partial exhalation has occurred. These scorching winds are sometimes called the samiel, and are supposed by some, to be pestilential in their nature.

In 1805, a caravan proceeding from Timbuctoo to Tafilet, was disappointed in not finding water at one of the usual watering-places, when, horrible to relate, the whole of the persons belonging to it, two thousand in number, besides one thousand eight hundred camels, perished of thirst! Accidents of this nature, account for the vast quantities of human and other bones which are found heaped together in various parts of the desert.

The following is the general route of the caravans, in crossing the great desert. Having left the city of Fez, they proceed at the rate of three miles and a half an hour, and travel seven hours each day. In the space of eighteen days they reach Akka, where they remain a month, as this is the place of rendezvous at which they are formed into one grand accumulated caravan. In proceeding from Akka to Tagassa, sixteen days are employed; and here again, the caravan sojourns fifteen days to refresh the camels. It then directs its course to the oasis and well of Taudeny, which is reached in seven days; and, after another stay of fifteen days, it proceeds to Arawan, a watering-place, situated at a like distance. After having sojourned there fifteen days, it sets out, and reaches Timbuctoo on the sixth day, after having performed a journey of fifty-four days of actual traveling, and seventy-five of repose; making, altogether, from Fez to Timbuctoo, one hundred and twenty-nine days, or four lunar months and nine days. Another caravan sets out from Wedinoon and Sok Assa, traversing the desert between the Black mountains of Cape Bojador and Gualata: it touches at Tagassa and El Garbie, or West Tagassa, where having staid to collect salt, it proceeds to Timbuctoo. The time occupied by this caravan is five or six months, as it proceeds as far as Gibbelel-bied, or the White mountains, near Cape Blanco, through the deserts of Mograffa and Woled Abusebah, to a place named Agadeen, where it sojourns twenty days.