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]

[Sidenote:  Spirit of independence among nomads.]

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 Sahara[1106] 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.