All the Saharan tribes are marauders, whether Arabs, Berber Tuaregs, or Negroid Tibbus. The desert has made them so. The Tuaregs are chronic freebooters; they keep the Sahara and especially the caravan routes in constant insecurity. They stretch a cordon across these routes from Ghadames and Ghat in the east to the great oases of Insalah and Twat in the west; and from the oases and hills forming their headquarters they spread for pasturage and blackmail over the desert.1078 They exact toll over and over again from a caravan, provide it with a military escort of their own tribesmen, and then pillage it on the way.1079 This has been the experience of Barth1080 and other explorers. Caravans have not been their only prey. The agricultural peoples in the Niger flood-plain, the commerce on the river, and the markets of Timbuctoo long suffered from the raids of the Tuaregs of the Sahara. They collected tribute in the form of grain, salt, garments, horses and gold, typical needs of a desert people, imposed tolls on caravans and on merchant fleets passing down the Niger to Timbuctoo. In 1770 they began to move from the desert and appropriate the fertile plains in the northern part of the Niger Valley, and in 1800 they conquered Timbuctoo; but soon they had to yield to another tribe of pastoral nomads, the Fulbes from the Senegal, who in 1813 established a short-lived but well organized empire on the ruins of the Tuareg dominion.1081 [See map page 105.] The other agricultural states of the Sudan have had the same experience. The Tibbus, predatory nomads of the French Sahara just north of Lake Chad and the River Yo, mounted on camels and ponies, cross the shrunken river in the dry season and raid Bornu for cattle, carry off women and children to sell as slaves, pillage the weekly markets on the Yo, and plunder caravans of pilgrims moving eastward to Mecca.1082 Nowhere can desert nomads and the civilized peoples of agricultural plains dwell side by side in peace. Raids, encroachments, reprisals, finally conquest from one side or the other is the formula for their history. [See map page 487.]

The raided territory, if a modern civilized state, organizes its border communities into a native mounted police, as the English have done in Bornu, Sokoto and the Egyptian Sudan, and as the Russians did with their Cossack riders along the successive frontiers of Muscovite advance into the steppes; or it takes into its employ, as we have seen, the nearest nomad tribes to repress or punish every hostile movement beyond. Among the ancient states the method was generally different. Since the nomad invaders came with their flocks and herds, a barrier often sufficed to block their progress. For this purpose Sesostris built the long wall of 1500 stadia from Pelusium to Heliopolis as a barricade against the Arabians.1083 Ancient Carthage constructed a ditch to check the depredations of the nomads of Numidia.1084 The early kings of Assyria built a barrier across the plains of the Euphrates above Babylon to secure their dominion from the incursions of the desert Medes.1085 In the fifth century of our era, the "Red Wall" was constructed near the northern frontier of Persia as a bulwark against the Huns. It stretched for a hundred and fifty miles from the Caspian Sea at the ancient port of Aboskun eastward to the mountains, and thus enclosed the populous valley of the Gurgen River.1086 In remote ages the neck of the Crimean Peninsula was fortified by a wall against the irruptions of the Tauro-Scythians.1087 The Russians early in their national history used the same means of defense against Tartar incursions. One wall was built from Pensa on the Sura River to Simbirsk on the Volga, just south of Kazan; another, further strengthened by a foss and palisades, extended from the fortress of Tsaritzin at the southern elbow of the Volga across the fifty-mile interval to the Don, and was still defended in 1794 by the Cossacks of the Don against the neighboring Kirghis hordes.1088 The classic example of such fortifications against pastoral nomads, however, is the Great Wall of China.

The nomad is economically a herdsman, politically a conqueror, and chronically a fighter. Strife over pasturage and wells meets us in the typical history of Abraham, Lot and Isaac;1089 it exists within and without the clan. The necessity of guarding the pastures, which are only intermittently occupied, involves a persistent military organization. The nation is a quiescent army, the army a mobilized nation.1090 It carries with it a self-transporting commissariat in its flocks and herds. Constant practice in riding, scouting and the use of arms, physical endurance tested by centuries of exertion and hardship, make every nomad a soldier. Cavalry and camel corps add to the swiftness and vigor of their onslaught, make their military strategy that of sudden attack and swifter retreat, to be met only by wariness and extreme mobility. The ancient Scythians of the lower Danubian steppes were all horse archers, like the Parthians. "If the Scythians were united, there is no nation which could compare with them or would be capable of resisting them; I do not say in Europe, but even in Asia," said Thucydides.1091 In this opinion Herodotus concurred.1092 The nomad's whole existence breeds courage. The independent, hazardous life of the desert makes the Arab the bravest of mankind, but the settled, agricultural Arab of Egypt and Mohammedan Spain lost most of his fighting qualities.1093

The daily life of a nomad horde is a training school for military organization. In the evening the flocks and herds are distributed with system around the camp to prevent confusion. The difficult art of a well ordered march, of making and breaking camp, and of foraging is practiced almost daily in their constant migrations.1094 The usual order of the Bedouin march could scarcely be surpassed by an army. In advance of the caravan moves a body of armed horsemen, five or seven kilometers ahead; then follows the main body of the tribesmen mounted on horses and camels, then the female camels, and after these the beasts of burden with the women and children. The encampment of tents with the places for men, arms and herds is also carefully regulated. More than this, the horde is organized into companies with their superior and subordinate leaders.1095 John de Carpini describes Genghis Khan's military organization of his vast Tartar horde by tens, hundreds and thousands, his absolute dominion over his conquered subjects, and prompt absorption of them into his fighting force, by the compulsory enlistment of soldiers out of every freshly subjugated nation.1096 In the same way the Hebrew tribes, when preparing for the conquest of Canaan, adopted from the desert Midianites the organization of the horde into tens, hundreds and thousands under judges, who were also military leaders in time of war.

Thus certain geographic conditions produce directly the habitual and systematic migration of the nomads, and through this indirectly that military and political organization which has given the shepherd races of the earth their great historical mission of political consolidation. Agriculture, though underlying all permanent advance in civilization, is handicapped by the lack of courage, mobility, enterprise and large political outlook characterizing early tillers of the soil. All these qualities the nomad possesses. Hence the union of these two elements, imperious pastor superimposed upon peaceful tiller, has made the only stable governments among savage and semi-civilized races.1097 The politically invertebrate peoples of dark Africa have secured the back-bone to erect states only from nomad conquerors. The history of the Sudan cannot be understood apart from a knowledge of the Sahara and its peoples. All the Sudanese states were formed by invaders from the northern desert, Hamitic or Semitic. [See map page 487.] The Galla or Wahuma herdsmen of East Africa founded and maintained the relatively stable states of Uganda, Kittara, Karague, and Uzinza in the equatorial district; the conquerors remained herders while they lorded it over the agricultural aborigines.1098 In prehistoric times when the various peoples of the Aryan linguistic family were spreading over Europe and southern Asia, the superiority of the shepherd races must have been especially marked, because in that era only the unobstructed surface of the steppes permitted the concentration of men on a vast scale for migration and conquest. Everywhere else regions of broken relief and dense forests harbored small, isolated peoples, to whom both the idea and the technique of combined movement were foreign.

The rapidity and wide scope of such conquests is explained largely by the fact that nomads try to displace only the ruling classes in the subjugated territory, leaving the mass of the population practically undisturbed. Thus they spread themselves thin over a wide area. How lasting are the results of such conquests depends upon the degree of social evolution attained by the herdsmen. Genghis Khan and Tamerlane, after the manner of overlords, organized their conquered nations, but left them under the control of local princes,1099 while their tribute gatherers annually swept the country like typical nomad marauders. The Turks are still only encamped in Europe. They too make taxation despoliation. And though their dominion has produced no assimilation between victor and vanquished, it has given political consolidation to a large area occupied by varied peoples. The Hyksos conquest of Egypt found the Nile Valley divided into several petty principalities under a nominal king. The nomad conquerors possessed political capacity and gave to Egypt a strong, centralized government, which laid the basis for the power and glory of the Eighteenth Dynasty. The Tartars in 1279 A.D. and the Manchus in 1664 conquered China, extended its boundaries, governed the country as a ruling class, and left the established order of things undisturbed. The Saracen conquest of North Africa and Spain showed for a time organization and a permanence due to the advanced cultural status of the sedentary Arabs drawn into the movement by religious enthusiasm. The environment of Spain tended to conserve the knowledge of agriculture, industry, architecture, and science which they brought in and which might have cemented Spaniard and Moor, had it not been for the intense religious antagonism existing between the two races.

The history of nomad conquerors shows that they become weakened by the enervating climate and the effeminating luxury of the moist and fertile lowlands. They lose eventually their warlike spirit, like the Fellatah or Fulbe founders of the Sudanese states,1100 and are either displaced from their insecure thrones by other conquerors sprung from the same nomad-breeding steppe, as the Aryan princes of India by the Mongol Emperor, and the Saracen invaders of Mesopotamia by the victorious Turkomans; or they are expelled in time by their conquered subjects, as the Tartars were from Russia, the Moors from Spain, and the Turks from the Danube Valley.

Nomad hordes unite for concerted action to resist encroachment upon their pastures, or for marauding expeditions, or for widespread conquest; but such unions are from their nature temporary, though a career of conquest may be sustained for decades. The geographically determined mobility which facilitates such concentration favors also dispersal, decentralization. This is the paradox in nomadism. Geographic conditions in arid lands necessitate sparse distribution of population and of herds. Pastoral life requires large spaces and small social groups. When Abraham and Lot went to Canaan from Egypt, "the land was not able to bear them that they might dwell together, for their substance was great." Strife for the pasturage ensued between their respective herdsmen, so the two sheiks separated, Lot taking the plains of Jordan and Abraham the hill pastures of Hebron. Jacob and Esau separated for the same reason. The encampment of the Kirghis shepherds rarely averages over five or six tents, except on the best grazing grounds at the best season of the year. The flow of spring, well or stream also helps to regulate their size. The groups of Mongol yurts or felt tents along the piedmont margin of the Gobi vary from four tents to a large encampment, according to water and grass.1101 Prevalsky mentions a population of 70 families or 300 souls in the Lob Nor district distributed in 11 villages, or less than 28 in each group.1102 Barth noticed the smallness of all the oasis towns of the Sahara, even those occupying favorable locations for trade on the caravan routes.1103

The nature-made necessity of scattering in small groups to seek pasturage induces in the nomad a spirit of independence. The Bedouin is personally free. The power of the sheik is only nominal,1104 and depends much upon his personal qualities. The gift of eloquence among the ancient Arabs has been attributed to the necessity of persuading a people to whom restraint was irksome.1105 Political organization is conspicuously lacking among the Tibbus of the Sahara1106 and the Turkoman tribes of the Trans-Caspian steppes. "We are a people without a head," they say. The title of sheik is an empty one. Custom and usage are their rulers.1107 Though the temporary union of nomadic tribes forms an effective army, the union is short-lived. Groups form, dissolve and re-form, with little inner cohesion. The Boers in South African grasslands showed the same development. The government of the Dutch East India Company in Cape Colony found it difficult to control the wandering cattlemen of the interior plateau. They loved independence and isolation; their dissociative instincts, bred by the lonely life of the thin-pastured veldt, were overcome only by the necessity of defense against the Bushmen. Then they organized themselves into commandos and sallied out on punitive expeditions, like the Cossack tribes of the Don against marauding Tartars. Scattered over wide tracts of pasture land, they were exempt from the control of either Dutch or English authority; but when an energetic administration pursued them into their widespread ranches, they eluded control by trekking.1108 Here was the independent spirit of the steppe, reinforced by the spirit of the frontier.

Though the desert and steppe have bred conquerors, they are the last parts of the earth's surface to yield to conquest from without. The untameable spirit of freedom in the shepherd tribes finds an ally against aggression in the trackless sands, meager water and food supply of their wilderness. Pursuit of the retreating tribesmen is dangerous and often futile. They need only to burn off the pasture and fill up or pollute the water-holes to cripple the transportation and commissariat of the invading army. This is the way the Damaras have fought the German subjugation of Southwest Africa.1109 Moreover, the paucity of economic and political possibilities in deserts and grasslands discourages conquest. Conquest pays only where it is a police measure to check depredations on the bordering agricultural lands, or where such barren areas are transit lands to a desirable territory beyond. It is chiefly the "Gates of Herat" and the lure of India which have drawn Russian dominion across the scorched plains of Turkestan. France has assumed the big task of controlling the Sahara to secure a safe passway between French Tunisia and the rich Niger basin of the French Sudan. The recent British-Egyptian expansion southward across the Nubian steppes had for its objective the better watered districts of the upper Nile above Khartum. This desert advance is essentially a latter day phenomenon, the outcome of modern territorial standards; it is attended or secured by the railroad. To this fact the projected Trans-Saharan line is the strongest witness.

Nature everywhere postpones, obstructs, jeopardizes the political conquest of arid lands. The unstable, fanatical tribesmen of the Egyptian Sudan, temporarily but effectively united under the Mahdi, made it necessary for Kitchener to do again in 1898 the work of subjugation which Gordon had done thirty years before. The body of the Arabian people is still free. The Turkish sovereignty over them to-day is nominal, rather an alliance with a people whom it is dangerous to provoke and difficult to attack. Only the coast provinces of Hejaz, Yemen and Hasa are subject to Turkey, while the tribes of the interior and of the southeastern seaboard are wholly independent.1110 The Turkoman tribes of Trans-Caspia have been subordinated to Russia largely by a process of extermination.1111 China is satisfied with a nominal dominion over the roaming populations of Mongolia and Chinese Turkestan. The French pacification and control of Northwest Africa meets a peculiar problem, due to the extreme restlessness and restiveness of the dominant Arab race. The whole population is unstable as water; a disturbance or movement in one tribe is soon communicated to the whole mass.1112

The steppe or desert policy for the curtailment of nomadism, and the reclamation of both land and people is to encourage or enforce sedentary life. The French, to settle the wandering tribes on the Atlas border of the Sahara, have opened a vast number of artesian wells through the agency of skillful engineers, and thus created oases in which the fecund sands support abundant date-palm groves.1113 The method pursued energetically by the Russians is to compress the tribes into ever narrowing limits of territory, taking away their area of plunder and then so restricting their pasture lands, that they are forced to the drudgery of irrigation and tillage. In this way the Yomuts and Goklans occupying the Caspian border of Trans-Caspia have been compelled to abandon their old marauding, nomadic life and become to some extent agriculturists.1114 The method of the Chinese is to push forward the frontier of agricultural settlement into the grasslands, dislodging the shepherd tribes into poorer pastures. They have thus reclaimed for grain and poppy fields considerable parts of the Ordos country in the great northern bend of the Hoangho, which used to be a nursery for nomadic invaders. A similar substitution of agriculture for pastoral nomadism of another type has in recent decades taken place in the semi-arid plains of the American West. Sheep-grazing on open range was with difficulty dislodged from the San Joaquin Valley of California by expanding farms in the sixties. More recently "dry farming" and scientific agriculture adapted to semi-arid conditions have "pushed the desert off the map" in Kansas, and advanced the frontier of tillage across the previous domain of natural pastures to the western border of the state.

Pastoral nomadism has been gradually dislodged from Europe, except in the salt steppes of the Caspian depression, where a vast tract, 300,000 square miles in area and wholly unfit for agriculture, still harbors a sparse population of Asiatic Kalmuck and Kirghis hordes, leading the life of the Asiatic steppes.1115 In Asia, too, the regions of pastoral nomadism have been curtailed, but in Africa they still maintain for the most part the growing, expanding geographical forms which they once showed in Europe, when nomadism prevailed as far as the Alps and the Rhine. In Africa shepherd tribes cover not only the natural grasslands, but lap over into many districts destined by nature for agriculture. Hence it is safe to predict that a conspicuous part of the future economic and cultural history of the Dark Continent will consist in the release of agricultural regions from nomad occupancy and dominion.

Though agriculture is regarded with contempt and aversion by pastoral nomads and is resorted to for a livelihood only when they lose their herds by a pest or robbery, or find their pasture lands seriously curtailed, nevertheless nomadism yields such a precarious and monotonous subsistence that it is not infrequently combined with a primitive, shifting tillage. The Kalmucks of the Russian steppes employ men to harvest hay for the winter feeding. The Nogai Tartars practice a little haphazard tillage on the alluvial hem of the steppe streams.1116 Certain Arab tribes living east of the Atbara and Gash Rivers resort with their herds during the dry season to the fruitful region of Cassala, which is inundated by the drainage streams from Abyssinia, and there they cultivate dourra and other grains.1117 The Bechuana tribes inhabiting the rich, streamless grassland of the so-called Kalahari Desert rear small herds of goats and cultivate melons and pumpkins; among the other Bechuana tribes on the eastern margin of the desert, the men hunt, herd the cattle and milk the cows, while the women raise dourra, maize, pumpkins, melons, cucumbers and beans.1118 [Compare maps pages 105, 487.]

Such supplementary agriculture usually shifts with the nomad group. But where high mountains border rainless tracts, their piedmont districts regularly develop permanent cultivation. Here periodic rains or melting snows on the ranges fill the drainage streams, whose inundation often converts their alluvial banks into ready-made fields. The reliability of the water supply anchors here the winter villages of the nomads, which become centers of a limited agriculture, while the pasture lands beyond the irrigated strips support his flocks and herds. Where the piedmont of the Kuen Lun Mountains draws a zone of vegetation around the southern rim of the Takla Makan Desert, Mongol shepherds raise some wheat, maize and melons as an adjunct to their cattle and sheep; but their tillage is often rendered intermittent by the salinity of the irrigating streams.1119 Along the base of the Tian Shan Mountains, the felt yurt of the Gobi nomad gives place to Turki houses with wheat and rice fields, and orchards of various fruits; so that the whole piedmont highway from Hami to Yarkand presents an alternation of desert and oasis settlement.1120 Even the heart of arid Arabia shows fertile oases under cultivation where the lofty Nejd Plateau, with its rain-gathering peaks over five thousand feet high, varies its wide pastures with well tilled valleys abounding in grain fields and date-palm groves.1121 Along the whole Saharan slope of the Atlas piedmont a series of parallel wadis and, farther out in the desert, a zone of artesian wells, sunk to the underground bed of hidden drainage streams from the same range, form oases which are the seat of permanent agriculture and more or less settled populations. The Saharan highlands of Tibesti, whose mountains rise to 8,300 feet, condense a little rain and permit the Tibbus to raise some grain and dates in the narrow valleys.1122

The few and limited spots where the desert or steppe affords water for cultivation require artificial irrigation, the importation of plants, and careful tillage, to make the limited area support even a small social group. Hence they could have been utilized by man only after he had made considerable progress in civilization.1123 Oasis agriculture is predominantly intensive. Gardens and orchards tend to prevail over field tillage. The restricted soil and water must be forced to yield their utmost. While on the rainy or northern slope of the Atlas in Algiers and Tunis farms abound, on the Saharan piedmont are chiefly plantations of vegetables, orchards and palm groves.1124 In Fezzan at the oasis of Ghat, Barth found kitchen gardens of considerable extent, large palm groves, but limited fields of grain, all raised by irrigation; and in the flat hollow basin forming the oasis of Murzuk, he found also fig and peach trees, vegetables, besides fields of wheat and barley cultivated with much labor.1125 In northern Fezzan, where the mountains back of Tripoli provide a supply of water, saffron and olive trees are the staple articles of tillage. The slopes are terraced and irrigated, laid out in orchards of figs, pomegranates, almonds and grapes, while fields of wheat and barley border the lower courses of the wadis.1126 In the "cup oases" or depressions of the Sahara, the village is always built on the slope, because the alluvial soil in the basin is too precious to be used for house sites.1127

The water supply in deserts and steppes, on which permanent agriculture depends, is so scant that even a slight diminution causes the area of tillage to shrink. Here a fluctuation of snowfall or rainfall that in a moist region would be negligible, has conspicuous or even tragic results. English engineers who examined the utilization of the Afghan streams for irrigation reported that the natives had exploited their water supply to the last drop; that irrigation converted the Kabul River and the Heri-rud at certain seasons of the year into dry channels.1128 In the Turkoman steppes it has been observed that expanding tillage, by the multiplication of irrigation canals, increased the loss of water by evaporation, and hence diminished the supply. Facts like these reveal the narrow margin between food and famine, which makes the uncertain basis of life for the steppe agriculturist. Even slight desiccation contracts the volume and shortens the course of interior drainage streams; therefore it narrows the piedmont zone of vegetation and the hem of tillage along the river banks. The previous frontier of field and garden is marked by abandoned hamlets and sand-buried cities, like those which border the dry beds of the shrunken Khotan rivers of the Tarim basin.1129 The steppe regions in the New World as well as the Old show great numbers of these ruins. Barth found them in the northern Sahara, dating from Roman days.1130 They occur in such numbers in the Syrian Desert, in the Sistan of Persia, in Baluchistan, the Gobi, Takla Makan Desert, Turfan and the Lop Nor basin, that they indicate a marked but irregular desiccation of central and western Asia during the historical period.1131

If a scant water supply places sedentary agriculture in arid lands upon an insecure basis, it makes the nomad's sources of subsistence even more precarious. It keeps him persistently on low rations, while the drought that burns his pastures and dries up well and wadi brings him face to face with famine. The daily food of the Bedouin is meal cooked in sour camel's milk, to which bread and meat are added only when guests arrive. His moderation in eating is so great that one meal of a European would suffice for six Arabs.1132 The daily food of the shepherd agriculturists on the Kuen Lun margin of the Takla Makan Desert is bread and milk; meat is indulged in only three or four times a month.1133 The Tartars, even in their days of widest conquest, showed the same habitual frugality. "Their victuals are all things that may be eaten, for we saw some of them eat lice." The flesh of all animals dying a natural death is used as food; in summer it is sun-dried for winter use, because at that time the Tartars live exclusively on mare's milk which is then abundant. A cup or two of milk in the morning suffices till evening, when each man has a little meat. One ram serves as a meal for fifty or a hundred men. Bones are gnawed till they are burnished, "so that no whit of their food may come to naught." Genghis Khan enacted that neither blood nor entrails nor any other part of a beast which might be eaten should be thrown away.1134 Scarcity of food among the Tibetan and Mongolian nomads is reflected in their habit of removing every particle of meat from the bone when eating.1135 A thin decoction of hot tea, butter and flour is their staple food. Many Turkoman nomads, despite outward appearance of wealth, eat only dried fish, and get bread only once a month, while for the poor wheat is prohibited on account of its cost.1136 The Saharan Tibbus, usually on a starvation diet, eat the skin and powdered bones of their dead animals.1137

The privations and hardships of life in the deserts and steppes discourage obesity. The Koko-Nor Mongols of the high Tibetan plateau are of slight build, never fat.1138 The Bedouin's physical ideal of a man is spare, sinewy, energetic and vigorous, "lean-sided and thin," as the Arab poet expresses it.1139 The nomadic tribesmen throughout the Sahara, whether of Hamitic, Semitic or Negro race, show this type, and retain it even after several generations of settlement in the river valleys of the Sudan. The Bushmen, who inhabit the Kalahari Desert, have thin wiry forms and are capable of great exertion and privations.1140

Though the conquering propensities of nomadic tribes make large families desirable, in order to increase the military strength of the horde, and though shepherd folk acquiring new and rich pastures develop patriarchal families, as did the Jews after the conquest of Canaan, nevertheless the limited water and food supply of desert and grassland, as well as the relatively low-grade economy of pastoral life, impose an iron-bound restriction upon population, so that as a matter of fact patriarchal families are rare. When natural increase finds no vent in emigration and dispersal, marriage among nomads becomes less fruitful.1141 Artificial limitation of population occurs frequently among desert-dwellers. In the Libyan oasis of Farafeah, the inhabitants never exceed eighty males, a limit fixed by a certain Sheik Murzuk.1142 Poverty of food supply explains the small number of children in the typical Turkoman family. Among the Koko-Nor Tibetans, monogamy is the rule, polygamy the exception and confined to the few rich, while families never include more than two or three children.1143 According to Burckhardt, three children constitute a large family among the Bedouins, much to the regret of the Bedouins themselves. Mohammedans though they are, few practice polygamy, while polyandry and female infanticide existed in heathen times.1144 Desert peoples seem to be naturally monogamous.1145

The prevailing poverty, monotony and unreliability of subsistence in desert and steppe, as well as the low industrial status, necessitate trade with bordering agricultural lands. The Bedouins of Arabia buy flour, barley for horse feed, coffee and clothing, paying for them largely with butter and male colts. The northern tribes resort every year to the confines of Syria, when they are visited by pedlers from Damascus and Aleppo.1146 The tribes from Hasa and the Nejd pasture land bring horses, cattle and sheep to the city of Koweit at the head of the Persian Gulf to barter for dates, clothing and firearms; and large encampments of them are always to be seen near this town.1147 Arabia and the Desert of Kedar sold lambs, rams and goats to the markets of ancient Tyre.1148 The pastoral tribes of ancient Judea in times of scarcity went to Egypt for grain, which they purchased either with money or cattle. The picture of Jacob's sons returning from Egypt to Canaan with their long lines of asses laden with sacks of corn is typical for pastoral nomads; so is their ultimate settlement, owing to protracted famine, in the delta land of Goshen. The Kirghis of the Russian and Asiatic steppes barter horses and sheep for cereals, fine articles of clothing, and coarse wooden utensils in the cities of Bukhara and the border districts of Russia. Occasionally the land of the nomad yields other products than those of the flocks and herds, which enter therefore into their trade. Such is the salt of the Sahara, secured at Taudeni and Bilma, the gums of the Indus desert, and balm of Gilead from the dry plateau east of Jordan.

The systematic migrations of nomads, their numerous beasts of burden, and the paucity of desert and steppe products determine pastoral tribes for the office of middlemen;1149 and as such they appear in all parts of the world. The contrast of products in arid regions and in the bordering agricultural land, as also in the districts on opposite sides of these vast barriers, stimulates exchanges. This contrast may rest on a difference of geographic conditions, or of economic development, or both. The reindeer Chukches of Arctic Siberia take Russian manufactured wares from the fur stations on the Lena River to trade at the coast markets on Bering Sea for Alaskan pelts. The sons of Jacob, pasturing their flocks on the Judean plateau, saw "a company of Ishmaelites come from Gilead with their camels bearing spicery and balm and myrrh, going to carry it down to Egypt."1150 This caravan of Arabian merchants purchased Joseph as a slave, a characteristic commodity in desert commerce from ancient times to the present. The predatory expeditions of nomads provide them with abundant captives, only few of which can be utilized as slaves in their pastoral economy. In the same way the Kirghis manage the caravan trade between Russia and Bukhara, sometimes adding captured travelers to their other wares. In ancient times Nubian shepherd folk acted as migrant middlemen between Egypt and Meroe near the junction of the Atbara River and the Nile, as did also the desert tribe of the Nasamones between Carthage and interior Africa.1151 From remote ages an active caravan trade was carried on between the productive districts of Arabia Felix and the cities of Mesopotamia, Syria and Egypt. Mohammed himself was a caravan leader; in the faith which he established religious pilgrimages and commercial ventures were inextricably united, while to the mercantile spirit it gave a fresh and vigorous impetus.1152 The caravan trade of the Sahara was first organized by Moorish and Arab tribes who dwelt on the northern margin of the desert, rearing herds of camels. These they hired to merchants for the journey between Morocco and Timbuctoo, in return for cereals and clothing. Hence Morocco has been the chief customer of the great desert town near the Niger, and sends thither numerous caravans from Tendouf (Taredant) Morocco, Fez and Tafilet. Algiers dominates the less important route via the oasis of Twat, and Tripolis that through Ghadames to the busy towns in the Lake Chad basin.1153

If the camel is "the ship of the desert," the market towns on the margin of the sandy wastes are the ports of the desert. Their bazaars hold everything that the nomad needs. Their suburbs are a shifting series of shepherd encampments or extensive caravanseries for merchant and pack animal, like the abaradion of Timbuctoo, which receives annually from fifty to sixty thousand camels.1154 Their industries develop partly in response to the demand of the desert or trans-desert population. The fine blades of Damascus reflected the Bedouin's need of the best weapon. Each city has its sphere of desert influence. The province of Nejd in Central Arabia is commercially subservient to Bagdad, Busrah, Koweit and Bahrein.1155 The bazaars of Samarkand and Tashkent exist largely for the scattered nomads of Turkestan. Ancient Gaza1156 and Askelon fattened on the Egyptian trade across the Desert of Shur, as Petra, Bostra and Damascus on the thin but steady streams of nomad products flowing in from the Syrian Desert.