SAHARA. 



Ttere M however tnct soross the desert, in which thM dangers 

 an comparatively uuulL It liat between 18 and 16 E. long., and 

 owns iu advantages partly to iu climate and parti; to iU soil It is 

 ble that thU tract oocun where no elevated country lies 

 the Mediterranean and the Sahara, but only the low range of 

 the HarnUh, which join* that arm of the Sahara that reached the 

 norm of the Mediterranean. The country along the shores of the 

 Golf of Sidra, between IS* and 19 E. long., and between the Gulf 

 and the Sahara, doe* not appear to riae in any part more than 1000 

 fset, and in most parta it is much lower. Through this wide gap the 

 northern wind*, which frequently blow a gale, and bring moisture 

 from the oountries north of the Mediterranean, which at that season 

 are drenched with rain, find access to the Sahara, and produce a con- 

 aiderable degree of cold even a* far south a* llourzuk. To these winds 

 alto we may probably ascribe the rain which falls in this season in the 

 dom of Feuan, and renders it the most fertile tract of the Sahara. 



kingdom 

 Thee* rains 



Thee* rains appear to extend to 21 N. lat, and as te nortern m 

 of the tropical rains occurs near 16 N. lat, the tract between the two 

 limits of rain does not exceed 5 degrees of latitude, whilst in other 

 places it occupies more than double that extent The advantages of 

 this tnct as a thoroughfare for cafiUs consist in the smaller extent of 

 the sandy tract* and of the continuous or broken ridges of rocks. 

 Though the rocky parts within the rainless region resemble the sandy 

 tracts in being without vegetation, the wells which occur between 

 them are more numerous, and rarely more than a few days' jour icy 

 from one another. The road through this country gives the easiest 

 access to the interior of Africa from the north. This road, after leaving 

 the town of Tripoli, runs south-east to the northern boundary of 

 Penan, over a country which partakes in some degree of the nature 

 of the Sahara, presenting a succession of plains and ridges of hills. 

 The hills are of inconsiderable height, generally not exceeding 400 

 feet, and never rising above 600 feet Many of them consist of lime- 

 stone overtopped by lava ; others are only sand-hills. They are without 

 vegetation, but contain between them many fertile valleys. This 

 country, which extends to the town of Sokna in Fezzan, has abundance 

 of wells and water. South of this place extends the Haruteh Assouat, 

 or Moos Niger, occupying a width of about 35 miles in a straight line. 

 Penan, which extends from this mountain tract to the northern tropic, 

 oonrirts of numerous small oases separated from each other by com- 

 paratively narrow tracts of sand. [KEZZAN.] Water is abundant, 

 except towards the southern boundary, where a level desert occurs, 

 which can only be traversed in four days ; but in the middle of it 

 there is a small place called Gatrone, surrounded by sandy hills and 

 mounds covered with small trees. At Kasrowa and Tegerhy there are 

 extensive plantations of date-trees and abundance of water. From the 

 southern boundary of Fezzan to the town of Bilma, or from 23 to 

 18* 80' N. lat, a continuous ridge of steep rocky hills, elevated from 

 $00 to $00 feet above the plain, runs almost due north and south ; and 

 from 6 to 20 miles east of this ridge there are isolated hills, mostly 

 composed of sand, but in some places of rock. Between these rocka 

 the road runs over a stony plain without the least vegetation, but 

 Denham says that after the rains a gras quickly springs up, which 

 is sereral feet high, and that the rains fall in torrents as far as the 

 Tiggerindumma Hills. It would therefore appear that in this tract the 

 northern rains extend to 21 N. lat No part of this country is 

 inhabited, but wells of drinkable water occur at distances of three or 

 four days' journey. Near 19 N. lat. however there are several small 

 towns or villages, which owe their existence not so much to a certain 

 degree of fertility in the soil, as to numerous small lakes which lie 

 along the foot of the rocky range, and in which trona crystallises. In 

 the vicinity of some of these lakes there are groves of date-trees and 

 pasture-ground for cattle. In some parts the soil is covered with 

 incrustations of pure trona, which extend for several miles in every 

 direction. In a few places mimosa-trees are .found. Bilma is noted 

 fcr ' t V*^*' Ta "^P't* [Bam], and in its vicinity there are a few 

 pou covered with vegetation. South of Bilma the road runs over 

 loose bill* of fine sand, in which the camels sink nearly knee-deep. 

 The hills sometimes disappear in a single night by the drifting of the 

 sand, and all traces of the passage, even of a large caravan, vanish in 

 a few hours. Wells are rare. After four days' travelling from Bilma 

 the wells of Dibla are met with ; and after four days more those of 

 Aghadem. The last-mentioned wells are abundant, and situated iu a 

 wooded valley, which however is not inhabited. After three days 

 more the country is reached which enjoys a small portion of the 

 tropical rains, and the soil improves. At first the sandy soil is inter- 

 spersed with clumps of grass, and here and there with low bushes ; 

 trees soon appear, and then increase in number. Thus the desert ceases 

 N. 1st, but no permanent habitations are met with until the 

 vicinity of Lari is reached, a town which is situated a short distance 

 from Lake Tchad (14 20' N. lat). The desert between Bilma and Lari 

 is called the Desert of Tintutna. 



The tnct just noticed ss traversing the desert from north to south, 

 divides the Sahara into two unequal portions, of which the western 

 and larger is known among the natives by the name of Sahel, and 

 theeasUrn sod smaller among geographers by that of the Libyan 

 Desert. 



Cbasf. Until lately many misconceptions prevailed respecting this 

 coast, which extends perhaps more than 1200 miles along the Atlantic. 



Modern surveys of the shore have shown that nearly the whole of the 

 coast is elevated, and consists of sandstone, which in most parts rises 

 to the height of 100 feet and more, but in some does not exceed 

 60 or 80 feet. A low coast only occurs between Cape Mirik (19 N. 

 lat) and the mouth of the river Senegal, but here, as at some other 

 parts of the coast, dunes, or sand-hills, are found at no great distance 

 from the shore, and behind these the flat country seems to have a con- 

 siderable elevation above the sea. The whole coast, as far south as 

 Cape Blanco, is free from sand-banks and shoals, and has regular 

 soundings. The depth gradually increases from the beach, and at the 

 distance of 4 miles there are from 30 to 34 fathoms ; at 12 miles from 

 50 to 60 fathoms; and at the distance of 30 miles about 100 fathoms. 

 The water then deepens very suddenly. A large sand-bank however 

 extends from Greyhound Bay (21 N. lat.) to Cape Mirik ; it is known 

 by the name of the Bank of Arguin, and on it the French frigate 

 Medusa was lost in 1816. The currents generally follow the direction 

 of the coast East of Cape Juby is a sudden bend of the coast, which 

 is the most dangerous place in the whole coast-line, as the swell is 

 almost invariably from the north-west, and consequently almost directly 

 on the coast ; besides this, the fine particles of sand which cover the 

 desert being blown into the sea and mingling with the haze occasioned 

 by the heavy surf, render this coast very indistinct. The greatest 

 strength of the current is usually at the distance of 3 to 6 miles from 

 the land, and it gradually decreases as it recedes from it The wind 

 generally blows from the north-west or west, and frequently in hard 

 gales, especially in the night. It is supposed that the rarefaction of 

 the air produced by the arid soil of the Sahara being heated to an 

 extraordinary degree by the almost perpendicular rays of the sun, 

 gives rise to the westerly winds along the coast of the Sahara. 



Soil. The Sahel, or western part of the desert, is by far the worst 

 part of the Sahara. It docs not appear that in all this vast extent a 

 single oasis occurs the soil of which is fit for agriculture or for the 

 growth of date-trees. The soil however varies greatly, passing from 

 a fine to a coarse sand and gravel, and then gradually to a bare layer 

 of broken stones and rocks. In many places hills of moderate eleva- 

 tion occur. Some of them consist of sand, and are subject to be 

 changed in size and form by the winds ; others consist of rocks, 

 frequently of granite and quartz. All these soils are destitute of 

 vegetation, which only appears in the depressions between the hills 

 and sometimes at the base of the rocky elevations, but it consists only 

 of a few grasses and shrubs. There appear to be numerous tracts, 

 though of small extent, which are fit for pasture ; for, according to all 

 accounts, the number of individuals who find subsistence in this part 

 of the Sahara is considerable, and they subsist altogether on the pro- 

 duce of their herds. It is stated, and with some degree of probability, 

 that the caravan-road has been purposely formed through the worst 

 part of the desert, the merchants being less afraid of the dangers of 

 the country than those which they would have to encounter if they 

 traversed a tract which is inhabited by numerous independent tribes, 

 each of which is eager to enrich itself by plundering the caravans or 

 subjecting them to a heavy tax for a free passage through their terri- 

 tories. It would appear that at no great distance from the sea the 

 country contains extensive pasture grounds, though of very inferior 

 quality, and frequently interrupted by tracts which are completely 

 sterile. Farther inland desert tracts entirely destitute of vegetation 

 and inhabitants are scattered over a much greater portion of the 

 couutry, but it is perfectly sterile and uninhabited only along the 

 caravan-road, so that the cafilas generally terminate their long journey 

 without meeting with a single person. The different tracts covered 

 with sand, gravel, and rocks, as well as the ridges of low hills which 

 occur along the caravan-road, run east and west, a fact which may 

 perhaps be accounted for by the circumstance of the wind almost 

 without exception blowing from the east. The couutry between this 

 road and the above-mentioned country between Tripoli and Lari is 

 inhabited by numerous tribes of Tuaricks. 



The Libyan Desert, or eastern part of the Sahara, contains a con- 

 siderable number of oases or fertile tracts, which support a moderate 

 population. Nearly all of them contain extensive groves of date-trees 

 and fields in which dhurra is grown. [EGYPT ; AUQILA.] 



Climate. It has been ascertained that no rain falls along the coast 

 south of Cape Juby. Some showers fall annually iu the countries south 

 of Mount Atlas, but it is not known how far inland they extend. 

 These showers fall between August and November. Along the coast 

 heavy dews occur in the summer mouths. In the interior the wind 

 blows almost without interruption from the east, and iu the day-time 

 frequently with the violence of a gale, which however is generally 

 followed by a dead calm after sunset. The strong wind moderates the 

 Ueat of the burning sun, and hence the nights are usually more insup- 

 portable than the noon-day heat. The violent gales frequently raise the 

 loose sand in such quantities that a layer of nearly equal portions of sand 

 and air, and rising about 20 feet above the surface of the ground, 

 seems to divide the purer atmosphere from the solid earth. This sand, 

 when agitated by whirlwinds, sometimes buries cafilas, and often puts 

 them into the greatest confusion. The degree of heat to whicli these 

 oountries are subject is variously stated. On the southern border of 

 the Sahara the thermometer at noon in summer rises to 107" ; iu .ome 

 other places to 120 and 140. The greatest degree of beat which is 

 experienced in the interior of the Sahara seems to occur in August 



