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SAHARA
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SAHARA , the See also:great See also:desert of See also:northern See also:Africa. The Sahara are connected with the See also:lower ranges of See also:Borku and Ennedi, which has an See also:area, according to Dr A. Bludau's calculation of the areas See also:merge into the plains of See also:Wadai and See also:Darfur. The slopes are See also:bare and rocky. By some authorities the Tasili of the Asjer, the Tummo, of See also:African See also:river basins, of 3,459,500 sq. m., made up as follows: See also:Tibesti and Borku ranges are considered " the orographic backbone " Sq. m. of the Sahara. Drainage or slope to See also:Atlantic . . 131,000 In addition to the plateaus and ranges named, there are several Drainage or slope to Mediterranean. 502,000 disconnected See also:mountain masses. Midway between the Atakor-'n- Drainage inland . . 2,602,500 Ahaggar and See also:Nigeria are the See also:Air or Asben hills in which Dr Erwin Slope to See also:Niger See also:basin . 224,000 von Bary discovered (1877) the distinct volcanic See also:crater of Teginjir with a vast See also:lava-See also:bed down its eastern See also:side. By some writers Air See also:Total . 3,459,500 (q.v.) is not included in the Sahara, as it lies within the limit of the This includes See also:Tripoli and See also:Fezzan, which practically belong to tropical rains; but the districts farther See also:south have all the See also:character-the desert See also:zone, but does not include arid portions of the basins istics of the desert. See also:West of Air, and See also:north-See also:east of the See also:bend of the of the See also:Nile and Niger, in which the drainage is at most inter- Niger, lies the hilly region sometimes known as See also:Adrar of the floras mittent, and which might with See also:reason be included in the Sahara. or of the Awellimiden (the See also:southern confederacy of the See also:Tuareg). To the N.E., in FEZZAN (q.v.), are the dark mountains of See also:Jebel-es- The area would thus be brought up to at least 3i million sq. in., Soda, which are continued S.E. towards Kufra by the similar range about the area of See also:Europe minus the Scandinavian See also:peninsula. of the Harui; and in the extreme S.W., at no great distance from the The See also:physical limits of this region are in some directions marked Atlantic, is the hilly See also:country of the western Adrar (q.v.). with great precision, as in parts of See also:Morocco and See also:Algeria, where Nearly all the See also:rest of the Sahara consists in the See also:main of undulating surfaces of See also:rock (distinguished as hammada), vast tracts of See also:water- the southern edge of the See also:Atlas range looks out on what worn pebbles (serir) and regions of sandy See also:dunes (variously called Area and has almost the See also:appearance of a boundless See also:sea, and ma hter, erg or are , i idi, and in the east rhart , which occupy 8 % & g ) py about See also:mss, forms, as it were, a bold See also:coast-See also:line, whose sheltered bays one-ninth or one-tenth of the total area. The following is the and commanding promontories are occupied by a See also:series See also:general See also:distribution of the dunes: — From a point on the Atlantic coast south of Cape Blanco a broad of towns and villages—Tizgi, Figuig, El Aghuat, &c. In other See also:belt extends N.E. for about 1300 m., with a breadth varying from directions the boundaries are vague, conventional and disputed. 50 to 300 M. This is usually called the Igidi or Gidi, See also:sana This is especially the See also:case towards the south, where the desert from the See also:Berber word for dunes. In See also:part it runs parallel dunes-. sometimes comes to a See also:close as suddenly as if it had been cut off with the Atlas mountains. Eastward it is continued, with a See also:knife, but at other times merges gradually and irregularly separated sprby a Algeria and See also:Tunisia, narrow valley a at t the Golea. Western South o and Eastern Erg; th of the Eastern Erg into the well-watered and fertile lands of the See also:Sudan. While (which extends as far north as the neighbourhood of the Gulf of towards the east the valley of the Nile at first sight seems to See also:Gabes) the continuity of the sandy See also:tract is completely broken by afford a natural frontier, the characteristics of what is usually the Hammada al-Homra (or Red Rock See also:Plateau), but to the south of called the Nubian desert are so identical in most respects with extend region to gion See also:lie Murzuthek in dunes Fezzan. South which, h, the with slight hammada of Murzuk intofrthose of the Sahara proper that some authorities extend this the dunes of Murzuk stretch south-east. This series of tracts may designation to the shores of the Red Sea. The desert, indeed, be called the northern zone of the Sahara; it forms a See also:kind of See also:bow, does not end with Africa, but is prolonged eastwards through with its extremities respectively at the Atlantic and the Libyan See also:Arabia towards the desert of See also:Sind. As the Nubian region is desert and its See also:apex in the south of Tunisia. In the south are the Juf (depressions), covering a vast area to the south-east of the described under SUDAN: § Anglo-See also:Egyptian, the See also:present See also:article is See also:middle portion of the Igidi, another area between the Adghagh confined to the country west of the Nile Valley, the Libyan plateau and the Ahaggar, and a third between Air and Tibesti. desert inclusive. Its greatest length, along the loth parallel of The Juf or depressions are not, except in rare instances, below sea- level. In the Libyan desert is a vast region of dunes of unascertained north See also:latitude, is some 3200 m.; its breadth north to south varies limits; the characteristics of the Libyan desert being thought typical from Boo to 1400 M. of the whole of the Sahara originated the See also:idea of " a sea of shifting The sea-like aspect of certain portions of the Sahara has given See also:sand " as descriptive of the entire desert. Here a region of over rise to much popular misconception, and has even affected the 500,000 sq. in. extending east from the Tibesti mountains to the ideas and phraseology of scientific writers. Instead of valley of the Nile, bounded south by Wadai and Darfur and north (letters, being a boundless See also:plain broken only by See also:wave-like and d Fezzan and e increasingl t covered bY 1CduneseaTherre is onlY n one know sroute aspect. mounds of sand hardly more See also:stable than the waves through this dreadful See also:wilderness—one See also:running "north and south of ocean, the Sahara is a region of the most varied See also:surface to the oases of Kufra, which lie in its centre." The dunes in the and irregular See also:relief, ranging from 100 ft. below to Libyan desert, so far as is known, run N.N.W. and S.S.E. In .the 5000 and Eastern Erg the dunes also lie in See also:long lines in a N.N.W. and S.S.E. 6000 and even in isolated instances to 8000 ft. above the sea- direction, presenting a See also:gradual slope to windward and an abrupt level, and, besides sand-dunes and oases, containing rocky descent to leeward. There they are generally about 6o or 70 ft. plateaus, vast tracts of loose stones and pebbles, ranges of the high, but in other parts of the Sahara they are said to attain a height most dissimilar types, and valleys through which abundant Under s of unwardh of 300 ft: the See also:influence of the See also:wind the surface of the dunes is subject watercourses must once have flowed. to continual See also:change, but in the See also:mass they have attained such a See also:state In the centre of the Sahara is a vast mountain region known as of See also:comparative See also:equilibrium that their topographic distribution may the Ahaggar (Hoggar) Tasili or plateau. The culminating peaks be considered as permanent, and some of them, such as See also:Gera (See also:Peak) of this plateau, Mounts Watellen and Hikena, are about 900 in. in al-Shuf and Gern Abd-al-Kader, to the south of Golea, have names a straight line almost due S. of the See also:city of See also:Algiers and about 1200 M. of their own. The popular stories about caravans and armies being due N. of the mouth of the Niger. They also occupy, speaking engulfed in the moving sands are regarded as apocryphal (See also:save roughly, a central position between the Atlantic and the Nile. perhaps in some instances in the Libyan desert), but there is abundant See also:evidence against the theory of M. Vatonne as to the dunes having been formed in situ. Although now mainly waterless, the Sahara possesses the See also:skeleton of s See also:regular river-See also:system. From the north side of the Atakor-'n-SkeJeion Ahaggar, through which runs the " water-parting" river- 'between the basins of the Mediterranean and Atlantic, system. begins See also:Wadi Igharghar, which, runping northwards between the Tasili plateau and the Irawen mountains, appears to lose itself in the sands of the Eastern Erg, but can be traced northwards for hundreds of See also:miles. Its bed contains rolled fragments of lava and See also:freshwater shells (Cyrena and Planorbis). In a line almost parallel to Wadi Igharghar, Wadi Mya descends from the plateau of Tademayt, and' shows the importance of its See also:ancient current by deep erosion of the Cretaceous rocks, in which a large number of See also:left-See also:hand tributaries have also left their See also:mark. The streams flowing south from the Atlas, which seem to be absorbed in the sands of the desert, evidently find a. series of underground reservoirs or basins capable of being tapped by artesian See also:wells over very extensive areas. As See also:Olympiodorus (quoted by See also:Photius) mentions that the inhabitants of the Sahara used to make excavations from See also:ioo to 120 ft. deep, out of which jets of pure water See also:rose in columns, it is clear that this state of matters is (historically) of ancient date. Since 1856 See also:French See also:engineers have carried on a series of borings which have resulted in the fertilizing of extensive tracts. In Wadi Righ (otherwise Rhir), which runs for 8o m. towards the south-west of the Shat Melrir (See also:department of See also:Constantine, Algeria), the water-bearing stratum is among permeable sands, which are covered to a See also:depth of 200 ft. by impermeable marls, by which the water is kept under pressure. In this valley many artesian wells have been sunk by the French. Connexions probably exist with subterranean water-supplies in the mountains to the north. That the water in the artesian reservoirs is kept aerated is shown by the existence below ground of fishes, crabs and freshwater molluscs, all of which were ejected by the well called Mezer in Wadi Righ. Further west the Wadis Zusfana and Ghir unite to See also:form the Saura, known in See also:Tuat as the Messaud. These See also:rivers still carry water as far as the northern part of Tuat; thence the course of the Messaud was, apparently, S.W. to the eastern Juf. There are also well-marked river-beds in the central Sahara. The Wadi Telemsi, rising in Adrar, of the Iforas, apparently joined the Niger nearGao, while the Wadi Taffassassent, which rose in the Ahaggar mountains, is believed to have been the ancient upper course of the lower Niger. The oases are also proofs of the presence of a steady See also:supply of underground moisture, for vegetation under the Saharan See also:climate (beyond the few See also:plants specially adapted to desert conditions) is exceptionally thirsty. The existence of these wadis or river-beds is a See also:factor in the See also:consideration of the cause of the desert nature of the country. In all parts of the Sahara there is evidence of denudation carried Dene out on a See also:scale of unusual magnitude. The present surface of the desert has been exposed to the protracted See also:wear and See also:tear of the elements. But to determine the exact method by which the elements have done their See also:work has hitherto proved beyond the See also:power of See also:science. The theory of submarine denudation was accepted by many scientists of the See also:mid-Victorian era. The sand-dunes, the See also:salt efflorescence and deposits, and the See also:local occurrence of certain See also:modern marine molluscs all go to help the See also:hypothesis of a diluvial sea. Nor is evidence lacking that in cretaceous times portions of the Sahara were covered by the sea. See also:Colonel P. L. See also:Monteil brought See also:home (1892) a fossil sea-urchin from See also:Bilma. In 1902 at Tamaske, some 250 m. W. of See also:Zinder, and a little north of See also:Sokoto, a See also:nautilus and four sea-urchins (fossils) were found by See also:Captain Gaden in a See also:limestone bed. Similar fossils occur in the, region between Zinder and Air, and others of the same See also:age have been found near See also:Dakar. Basing his conclusions on these and other facts, de See also:Lapparent held that an See also:arm of the sea extended inland from the Atlantic to the eastern Sahara. This sea was bounded on the north and east by the mountains of Air, Ahaggar, the Asjer Tasili, &c. An extensive acquaintance with Saharan characteristics shows, however, that a sea for the Sahara as a whole is impossible. See also:Henri See also:Schirmer, who in 1893 published an admirable See also:summary of Saharan See also:geography up to that date, argued that the desert nature of the Sahara is due to forces which have been at work for ages, although, as in all deserts, the dryness is probably progressively increasing. The See also:primary cause is to be sought in the existing distribution of See also:land and sea, the great land mass of North Africa causin an outflow of air in all directions (and consequent See also:absence of See also:rain) in See also:winter, and an in-See also:draught in summer, when the surface is intensely heated and the relative humidity of the See also:atmosphere becomes so small that condensation is all but impossible. The vicinity of the comparatively cool Mediterranean in the north accentuates the f"orce of the winds from that direction, which, blowing towards a lower latitude, are in their very nature dry winds. The influence of mountain ranges, such as the Atlas, See also:round the border of the desert, is thus but a sub-See also:ordinate cause of the latter's dryness, which would probably be little diminished did the Atlas not exist. This dryness reacts again on the temperature conditions of the Sahara, accentuating both the daily and See also:annual variation. The intense See also:heat of the See also:day is compensated by the See also:cold of the nights, so that the mean annual temperature is not excessive. The difference between the mean temperature ofthe hottest and coldest See also:month Ms been found to be as high as 45° F., and the extreme range at least 90° F., See also:maxima of I12 and over having been frequently observed. As a result of the extreme dryness of the air, evaporation is excessive, and, being greater than the precipitation, involves a progressive See also:desiccation of the Sahara.. The surface of the rocks, heated by the See also:sun and suddenly chilled by rapid See also:radiation at See also:night, gets fractured and crumbled; elsewhere the cliffs have been scored and the sand thus formed is at once turned by the wind into an active See also:instrument of See also:abrasion. in many places it has planed the See also:flat rocks of the hammada as smooth as See also:ice. Elsewhere it has scored the See also:vertical faces of the cliffs with curious imitations of glacial striation, and helped to undercut the See also:pillar or table-like eminences—remains of former more extensive plateaus—which, under the name gur, are among the most See also:familiar products of Saharan erosion. The softer See also:quartz rocks of the See also:Quaternary and Cretaceous series have been made to yield the sand which, drifted and sifted by the winds, has taken on the form of dunes. The slighest See also:breeze is enough to make the. surface ":See also:smoke " with dust; and at times the weird singing of the sands, waxing louder and louder, tells the scientific traveller that the See also:motion is not See also:con-fined to the superficial particles. The dry wind of the Sahara is known in southern Europe as the See also:Sirocco. It brings with it clouds of See also:fine red dust, as noted long since by See also:Idrisi, the Arabian geographer. Dr See also:Theobald See also:Fischer and Dr Oscar See also:Fraas agree in believing that the desiccation has markedly increased in historic times. Evidence derived from ancient monuments combined with the statements of See also:Herodotus and See also:Pliny are held to prove that the See also:elephant, the See also:rhinoceros, and the See also:crocodile existed in North African regions where the environment is now utterly See also:alien, and on the other hand that the See also:camel is a See also:late introduction. Any See also:attempt to improve the See also:climatic conditions of the Sahara as a whole can hardly meet with success when the causes of its desiccation are considered. Much may, however, be done to modify local conditions, and fairly satisfactory results have been obtained in the direction of fixing the dunes and covering them with a growth of vegetation. Experiments carried out by the French at See also:Ain Sefra, on the northern border of the desert, have shown that by protecting the sand from the See also:action of the wind by a See also:litter of alfa grass, See also:time is given for the See also:establishment of suitable trees, which include the See also:tamarisk, See also:acacia, See also:eucalyptus, prickly See also:pear, See also:peach and See also:aspen See also:poplar, the last-named having proved the most capable of all of resisting the desert conditions. Such planting operations can only be carried out in favourable localities, such as' valleys in which a certain amount of water is available. Wide areas like the arid stony plateaus (hammada) must be abandoned as hopeless. As already stated, the popular conception of the Sahara as a sand desert is erroneous. It is really a stony, wind-swept See also:waste with much bare rock visible, the actual area of pure sand fleolo forming a relatively small portion. A broad belt of gical Archaean rocks extends throughout the desert, appearing structure' at intervals in the form of hills and plateaus from beneath the superficial sands and Quaternary deposits Examples are the See also:granite of Air and the See also:gneiss and See also:mica-See also:schists of this See also:massif and of the Ahaggar plateau. Flanking this zone are immense tracts occupied by rocks of Devonian and Carboniferous ages, from which characteristic marine fossils have been obtained at the springs of El Hassi and between See also:Wad Draa and the dunes of Igidi. Productus See also:africanus is a See also:common fossil of the Carboniferous rocks. At the close of the Carboniferous See also:period it has been generally considered that the southern and central Sahara became dry land and has remained so up to the present day. Marine fossils of Cretaceous age have, however, been found within See also:recent years in the central ;regions; while See also:Eocene echinoids have been obtained near Sokoto (Geol. Mag., 1904). During Lower Cretaceous times the Mediterranean covered the Algerian and Tripolitan Sahara and the northern portion of the eastern desert; the extensive development of the Cretaceous system being, one of the most striking features of Saharan See also:geology. At,the close of the Cretaceous period the Tripolitan Sahara completely emerged,' but parts of the Tunisian and Algerian Sahara seem to have remained below sea-level until the end of the Lower Eocene. Only on the extreme See also:borders of the desert, however, do See also:tertiary formations See also:play any prominent part. During the Quaternary, period the Sahara possessed a moister climate than the present. This is shown by the numerous water-cut valleys, now dry, and by the remains of See also:hippopotamus in the Quaternary deposits. The idea so long held that the Sahara represented the recently dried-up bed of an See also:extension of the Mediterranean has been disproved by the investigations of French geologists. The sand is mainly derived from the wide expanse of Cretaceous sandstones, which become rapidly disintegrated by the contraction caused by the wide range of temperature between day and night. The loose sands of the Quaternary deposits also furnish abundant material. The true dune sand is remarkable for the uniformity of its See also:composition and the geometrical regularity of its grains, which measure less than •03937 in. While individually these appear transparent or reddish yellow (from the presence of See also:iron), they have in the mass a See also:rich See also:golden See also:hue. According to Tissandier See also:animal organisms, such as the microscopic shells of See also:Rhizopoda, abundant in sea-sand, are strikingly absent:
Botanically the Sahara is the See also:meeting-ground of representatives
of the " Mediterranean " and the " Tropical " floras which have accommodated themselves to the See also:peculiar climatic conditions. The line of demarcation between the two floral areas, almost coinciding in the west with the Tropic of See also:Cancer and in the east
Botanyand bdipping y far the greater portion of the area to " Mediterranean ne assigns See also:Zoology. infuences. Uniformity, in spite of See also:differences of See also:altitude and See also:soil, is a general characteristic of the vegetation, which outside of the oases consists mainly of plants with a tufty, dry, stiff See also:habit of growth. The oases are the See also:special home of the date-See also:palm, of which there are about 4,000,000 in the Algerian oases alone. In See also:company with this See also:tree, without which See also:life in the Sahara would be practically impossible, are grown apples, peaches, oranges, citrons, See also:figs, grapes, pomegranates, &c. From See also:December to See also: Zoologically the Sahara is also partly Mediterranean, partly Tropical. Apart from the domestic animals (camels, asses, &c., and very noticeably a See also:black breed of See also:cattle in Adrar), the See also:list of fifteen mammals comprises the See also:jerboa, the fennek or See also:fox, the See also:jackal, the sand See also:rat (Psammomys obesus), the See also:hare, the See also:wild See also:ass and three species of See also:antelope. In Borku, Air, &c., baboons, hyaenas and mountain See also:sheep are not uncommon. Without counting migratory visitants, about eighty species of birds have been registered—the See also:ostrich, the Certhilauda deserti or desert-See also:lark (which often surprises the traveller with its See also:song), Emberiza Saharae, three species of Dromolea, &c. Tortoises, lizards, chameleons, geckos, skinks, &c. of fifteen different species were collected by the single See also:Rohlfs expedition of 1873–1874; the serpents comprise the horned See also:viper, Psammophis sibilans, Coelopeltis lacertina, the See also:python and several other species. The edible See also:frog also occurs. Cyprinodon dispar, a See also:fish not unlike Cyprinodon calaritanus, is found In all the brackish See also:waters of north Sahara and swarms in the See also:lake of the See also:Siwa See also:oasis. The See also:chief centres of See also:population in the Sahara are, firstly, the oases, which occupy positions where the underground water makes its way to the surface or is readily reached by See also:tees See also:boring; and, secondly, certain mountainous districts of popula- tion. where the atmospheric moisture is condensed,'and a moderate rainfall is the result. Except in the south of Algeria, where cultivation has been extended by means of artesian wells, the See also:condition of the Sahara oases is far from prosperous. See also:Prior to the French occupation, a feeling of in-See also:security had been engendered by the marauding habits of the See also:nomad tribes; cultivation had become more restricted; and the decline of the See also:caravan See also:trade had brought ruin to certain centres, such as Murzuk. The most important are the oases of the Tuat region, especially Insalah; those of See also:Ghat and See also:Ghadames on the route from Tripoli to See also:Tinder; and of Kufra, in eastern Sahara (see TUAT and Tx1Ponr). The various confederations of the Tuareg, in the central Sahara, are grouped round hilly districts. The most important are the Awellimiden, on the left See also:bank of the Middle Niger; and the Kel-Ui, grouped around the mountainous districts of Air or Asben; the two northern con-federations, those of the Ahaggar and Asjer, being less powerful. Much See also:information respecting the Awellimiden See also:confederation was obtained during the voyage down the Niger, in 1896, of See also:Lieutenant Hourst of the French See also:Navy, who was much struck with its powerful organization under the chief Madidu. North-west of See also:Timbuktu in the See also:district or " See also:Kingdom " of Biru is the oasis and See also:town of Walata, a Tuareg See also:settlement. Other mountainous districts in which a certain amount of rain falls regularly, and which contain a population above the See also:average for the Sahara, are Tibesti and Borku, in the east centre, and Adrar in the west. Tibesti and Borku are peopled by Tibbus; the western Adrar by See also:Moors (See also:Berbers). The northern portions of the Sahara are inhabited by nomad See also:Arabs. Attempts have been made by many explorers and writers to trace in certain of the existing inhabitants the remnants of an aboriginal See also:race of See also:negro See also:affinities, which inhabited the See also:Ethnology. Sahara before the arrival of the Berbers and Arabs. E. F. See also:Gautier, See also:writing in 1908, maintained that the evidence available (for the central Sahara) rendered probable the hypothesis that at a period perhaps as recent as the See also:Roman See also:conquest of North Africa the Sahara was still See also:neolithic and peopled by a race of agricultural negroes, who extended to the confines of Algeria. Negro influence is undoubtedly seen in various parts of the Sahara, but it may date from a much more recent perio8 than has been supposed. For example, the connexion between many of the See also:place-names in Fezzan and the See also:language of See also:Bornu is attributable to the northward extension of the influence of the Bornu-Kanem See also:empire between the See also:firth and 14th centuries A.D. The allusions by classical writers to Ethiopians as inhabitants of the Sahara prove little, in view of the very vague and general meaning attached to the word. The physical characteristics, and especially the dark See also:colour, of many of the Saharan populations is apparently a stronger See also:argument, but even this is capable of another explanation. Caravans of negro slaves from time immemorial passed northwards along the main desert routes, and it is just in the oases on these routes that the dark See also:element in the population is chiefly found. It may there-fore be attributed to the intermarriage of the See also:original lighter inhabitants of the oases with such slaves. The See also:Tibbu (q.v.) or Tebu, once thought to be almost pure negroes, proved, when examined by Gustav See also:Nachtigal in Tibesti, where they are found in greatest purity, to be a See also:superior race with well-formed features and figures, of a See also:light or dark See also:bronze rather than black. Their language is related to that of the See also:Kanuri in Bornu, but it appears that the Kanuri have derived theirs from the Tibbu, not the Tibbu from the Kanuri. Physically, the Tibbu appear to resemble somewhat the Tuareg, and there is little doubt that they are a Hamitic, not a negro, See also:people. The See also:commerce of the Sahara is not inconsiderable. Among the more important trade routes are (1) from Morocco to See also:Cairo by Insalah and Ghadames, which is followed by the Comamera. pilgrims of western Africa See also:bound for See also:Mecca; this route has been largely superseded by the sea route from See also:Tangier to . See also:Alexandria; (2) from See also:Kuka (Lake See also:Chad) to Murzuk and Tripoli; (3) from See also:Kano and Zinder to Tripoli by Air and Ghat; (4) from Timbuktu to Insalah, Ghadames and Tripoli;(5) from Timbuktu to Insalah and thence to Algeria and Tunisia; (6) from Timbuktu to Morocco. The See also:Senussi See also:movement brought into prominence the desert routes between Wadai in the south and Jalo and Benghazi in the north, which partially superseded some of the older routes. Other causes tended to reduce the importance of the old routes. The long-established route from Darfur to the See also:Kharga and Dakhila oases See also:fell into disuse on the closing of the eastern Sudan by the Mandist troubles. The great route leading from Tripoli via Ghadames and Ghat, to Zinder, Kano, and other great centres of the See also:Hausa States maintains its importance, but the opening of trade from the side of the Niger by the See also:British in the See also:early years of the loth See also:century affected its value. The route across the western Sahara to Timbuktu is less used than formerly owing to the establishment by the French of a route from See also:Senegal via Nioro to the Upper Niger. The old route, however, retains some importance on See also:account of the salt trade from the Sahara, which centres at Timbuktu. Salt and date palms are the chief products of the Sahara. The See also:principal See also:sources of the salt supply are the rock-salt deposits of the Juf (especially Taudeni), the lakes of Kufra and the rock salt and brine of Bilma (q.v.). The See also:hope of an eventual commercial exploitation of the Sahara rests mainly on the possible existence of See also:mineral See also:wealth. To supply easy communication between Algeria and Nigeria the Trans. construction of a railway across the desert has found Saharan many See also:advocates. Two principal routes have been Rauwgy suggested, the one taking an easterly line from See also:Biskra schemes. through See also:Wargla to Air (Agades) and Zinder—generally, the route followed by Foureau (see below); the other starting from the See also:terminus of the most See also:westerly railway already existing, and reaching Timbuktu via Igli and the Tuat oases. A third suggested route is one from Igli to the Senegal, still farther west. Reference may also be made to the proposal, strenuously advocated between 187o and 1885, to open up the region to the south of Algeria and Tunisia by the construction of an inland sea. The According to Colonel See also:Francois Roudaire (1836-1885), the Floedlag author of this See also:scheme, deceptively styled the " flooding of the of the Sahara," it was possible to create an inland sea Sahara with an average depth of 78 ft. and an area of 3100 sq. in., or about fourteen times the See also:size of the Lake of See also:Geneva. A French See also:government See also:commission decided that the excavation of the necessary See also:canal would not be difficult, and that in spite of silting-up processes the canal when cut would at least last loon to 1500 years. See also: A further agreement in 1904 again modified the frontier in favour of France. To the north-east and east the boundary of the French See also:sphere was extended, by an Anglo-French See also:Declaration of March 1899, and defined as running south-east, from the intersection of the Tropic of Cancer with 16° E., until it meets the See also:meridian of 24° E., following this south to the frontier of Darfur. French Sahara is thus connected with the French possessions in West Africa and with the See also:Congo-See also:Shari territories of France on the south-east. On the west, where See also:Spain claimed the Sahara coast between Capes Blanco and Bojador, the inland frontier was defined by the Franco-See also:Spanish agreement of 1900, whereby Spain was apportioned a See also:Hinterland with an average depth of 240 M. from the sea-See also:shore. It is impossible to ascertain the extent of the knowledge of the Sahara possessed by the ancients. The Egyptians penetrated the Libyan and Nubian deserts at points, and Carthaginians Dragons" and Phoenicians were acquainted with the northern d'n' fringe of the desert in the west. See also:European exploration See also:dates from the beginning of the 19th century. In 1819 Captain G. F. See also:Lyon and See also:Joseph See also:Ritchie penetrated from Tripoli to Murzuk, where Ritchie died. In 1822 came the great See also:journey of See also:Walter Oudney,See also:Hugh Clapper ton and See also:Dixon See also:Denham, from Tripoli to Lake Chad, and a See also:year or two later See also:Major A. G. See also:Laing succeeded in reaching Timbuktu, also from Tripoli. In 1828 Rene Caillie crossed from Timbuktu to Morocco. Heinrich See also:Barth in the course of his great journey (1849-1856), commenced from Tripoli under the leadership of See also: This journey was undertaken in pursuance of the efforts of the French to obtain effective See also:control of the Sahara. South of Algeria military posts had been gradually pushed into the desert, Golea being until 1900 the farthest point which acknowledged French See also:rule. The great desideratum was the opening up of a route to the Niger countries which might in time divert the trade from Tripoli to Algeria, but all attempts long proved fruitless, owing to the opposition of the tribes inhabiting central Sahara. In 1886 Lieutenant Palat was murdered a little south of Gurara, and in 188o the same See also:fate befell Camille Douls in Tidikelt (Tuat) in his attempt to reach Timbuktu from the north. In 1890 Foureau —who in 1883 had undertaken a first journey of explorationsouth of Wargla—reached the Tademayt plateau in 28° N., fixing the position of 35 places, and in 1892-1893 came the first of his long series of expeditions undertaken with a view of penetrating the country of the Azjer Tuareg, the powerful confederacy which See also:lay on the route to Air and Lake Chad, never traversed in its entirety by a European. All efforts to obtain a passage were unavailing until in 1898-1899 Foureau, accompanied by an escort of troops under Major Lamy, at last attained his See also:object, finally reaching Zinder, the important trade centre on the borders of Nigeria, and midway between the river Niger and Lake Chad, on the 2nd of See also:November 1899. The important See also:section of Foureau's route began at Ain El-Hajaj, in about 264° N., immediately beyond which the frowning massif of Tindesset had to be crossed by a most difficult route among a See also:chaos of rocks and ravines, the See also:geological formation being principally See also:sandstone. After descending the southern escarpment of the " Tasili," the expedition crossed the mountainous region named Anahef, composed of quartz and granite, through which the line of See also:partition between the basins of the Mediterranean and Atlantic was found to run. Thence the route lay across the wide plain of quartz See also:gravel, strewn with blocks of granite, known to the Tuareg as Tiniri, to the well of In-Azaua, beyond which a march of eleven days, with a water-supply at one point only, led to the first See also:village of Air, where the Tuareg proved hostile. Agades, the See also:capital of Air, was reached by a march through difficult mountains, with valleys which gradually opened into a wide plain. From Agades to Zinder the route lay, first, through the bare and arid district of Azauak; next, through the See also:bush-covered Tagama, a district abounding in See also:game; and, lastly, through the cultivated country of Darnerghu. Zinder had only once before been reached by way of Air—by Barth's expedition in 185o. It was now occupied by a French force which had advanced from the Niger (see SENEGAL, : See also:Colony). Foureau's achievement was quickly followed by increased See also:political activity of the French in the Sahara south of Algeria, where, in addition to the work of other explorers, surveys had been carried by French See also:officers (especially Captains Germain and Laperrine in 1898) as far as the important centre of Insalah, the position of which had, as a result, been shifted some 25 M. E. of its former position on the maps, being found to lie in 20 16' E., 20° 17' 3o"N. Early in 190o G. B. M. Flamand, who had been entrusted with a scientific See also:mission to the Tuat oases, came into collision with the natives, and Insalah was occupied by the military escort which accompanied him. This was quickly followed by the occupation of Tuat, and Igli (see TUAT). Simultaneously with these events, an attempt was made to pave the way for the establishment of French influence in western Sahara by the expedition of Paul Blanchet to Adrar, which had not been visited since the middle of the 19th century. It returned in See also:September 1900, only partially successful, Blanchet and his companions having been detained for some time as virtual prisoners on the borders of Adrar. The See also:leader almost immediately succumbed to See also:fever. In 1903-1909 the country N. of the lower Senegal, including Adrar, was brought under French control and organized as the territory of See also:Mauretania. The most marked progress was, however, effected in the central Sahara, where the French posts were gradually pushed farther south under a military organization, which resulted in the See also:complete pacification of the Tuareg countries. Travel was thus made possible from one border of the desert to the other, and a number of successful expeditions gathered a rich See also:harvest of results respecting the mapping, geology, and other features of this part of the Sahara. Some of the best work was done by Laperrine, See also:Arnaud, Cortier and Nieger on the military side, and, on the civilian, by Villatte, Gautier and Chudeau. Apart from these French enterprises, Hanns See also:Vischer, a Swiss in the service of British Nigeria, in 1906 travelled from Tripoli to Bornu through Murzuk and Bilma. In 1910 Capt. A. H. See also:Haywood traversed the Sahara, being the first Englishman to See also:cross the desert from See also:Gao to Insalah. AuTHolITLEs.—Vatonne, Mission de Ghadames (1863); H. Duveyrier, See also:Les Touaregs du See also:Nord (1864) ; Ville, Ex See also:plot.. geologique du Msab, &c. (1867) ; A. Pomel, Le Sahara (1872) ; F. G. Rohlfs, Quer See also:lurch Afrika (1874), Drei Monate See also:im libyschen Wuste (1875) and Kufra (1881); V. Largeau, Le Pays de Rirha-Ouargla( i 879) ; G. Nachtigal, Sdhdrd and S4ddn (3 vols., 1879-1889) ; G. See also:Rolland, " Le Cretace du Sahara septentrional " (with geological See also:map of the Central Sahara), in See also:Bull. de la See also:Soc. Geol. de France (1881) ; Roudaire. Rapport sur la dernierd expect. See also:des Chotts (1881) (and other reports by the same author); Tchihatchef, " The Deserts of Africa and See also:Asia," in British Association Reports (See also:Southampton, 1882); Derrecagaix, " Explor. du Sahara: les deux See also:missions du Lieut.-Colonel Flatters," in Bull. de la Soc. de Geogr. (1882); O. Lenz, Timbuktu. Reise durch Marokko, &c. (1884) ; and E. L. See also:Reclus, Nouv. Geographie univ. xi. (i886); H. Schirmer, Le Sahara (See also:Paris, 1893); P. Vuillot, L'Exploration du Sahara (Paris, 1895) ; P. L. Monteil, De See also:Saint-See also: See also:Zittel, Palaontologie der libyschen Wiiste (See also:Cassel, 1893) ; G. Rolland, Chemin de fer transsaharien, geologie du Sahara algerien, et apercu
feologique sur le Sahara de l'ocean atlantique a la mer See also:rouge (Paris, mp. Nat., 1891); J. See also:Walther, See also:Die Denudation in der Wiiste (See also:Leipzig, 1900) ; M. Honore, Le Transsaharien et la penetration francaise en Afrique (Paris, 1901); E. Durkop, Die wirtschafts- and handelsgeographischen Provinzen der Sahara (See also:Wolfenbuttel, 1902) ; W. J. See also:Harding See also: 447-517; J. Lahache, " Le Dessechement de l'Afrique francaise est-il demontre?" Bul. Soc. Geogr. Marseille, 31 (1907), pp. 149-185; E. Arnaud and M. Cortier, Mission Arnaud-Cortier; nos confins sahariens (Paris, 1908) ; E. F. Gautier and R. Chudeau, Missions au Sahara, t. i. " Sahara algerien," par E. F. Gautier (Paris, 1908), t. ii. " Sahara sudanais," par R. Chudeau (Paris, 1909) ; H. Vischer, Across the Sahara from Tripoli to Bornu (London, 1910) ; H. J. LI. Beadnell, " Sand Dunes of the Libyan Desert," Geog. Jour. (See also:April 1910) ; E. Fallot, " Le Commerce du Sahara," Ques. See also:dip. et See also:col. t. 15 (1903), pp. 209-225. (E. HE.; F. R. Additional information and CommentsThere are no comments yet for this article.
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