n,
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]

[Sidenote: Desert markets.]

If