rn
peoples. The Great Trek of the South African Boers in 1836, by which
they renounced not only their unwelcome allegiance to England, but also
their land,[1061] was another exodus in accordance with the instinct of a
pastoral people. They adopted no strange or difficult course, but
traveled with their families as they were wont in their every day life
of cattle-tenders, took all their chattels with them, and headed for the
thin pastures of the far-reaching veldt. The Russian government has had
to contend with a like fluidity in her Cossack tribes of the steppes,
who have been up and off when imperial authority became oppressive. In
the summer of 1878 West Siberia lost about 9000 Kirghis, who left the
province Semipalatinsk to seek Mongolia.

[Sidenote: Seasonal migrations.]

Environment determines the nomadic habits of the dweller of desert and
steppe. The distribution of pasture and water fixes the scope and the
rate of his wandering; these in turn depend upon geographic conditions
and vary with the season. The Papago Indians of southern Arizona range
with their cattle over a territory 100 by 150 miles in extent, and
wander across the border into Mexico. When their main water supply,
derived from wells or artificial reservoirs near their summer villages,
is exhausted, they migrate to the water-holes, springs or streams in the
canons. There the cattle graze out on the plains and return to the
canons to drink.[1062] Every Mongol tribe and clan has its seasonal
migration. In winter the heavier precipitation and fuller streams enable
them to collect in considerable groups in protected valleys; but the dry
summer disperses them over the widest area possible, in order to utilize
every water-hole and grass spot. The hotter regions of the plains are
abandoned in summer for highlands, where the short period of warmth
yields temporary pastures and where alone water can be found. The
Kirghis of Russian Turkestan resort in summer to the slopes and high
valleys of the Altai Mountains, where their auls or tent villages may be
seen surrounded by big flocks of sheep, goats, camels, horses and
cattle.[1063] The Pamir in the warm months is the gathering place for the
nomads of Central Asia. The naked desert of Arabia yields a rare herbage
during the rainy season, when the Bedouin tribes resort to it for
pasturage;[1064] but during the succeeding drought they scatter to the
hills of Yemen, Syria and Palestine,[1065] or migrate to the v