northern desert, which belongs geographically to
Arabia rather than to Syria; while on the same grounds lower Mesopotamia
and Irak, although occupied by an Arab population, are excluded.

In shape, the peninsula forms a rough trapezium, with its greatest
length from north-west to south-east. The length of its western side
from Port Said to Aden is 1500 m.; its base from the Straits of
Bab-el-Mandeb (or Bab al Mandab) to Ras el Had is 1300 m., its northern
side from Port Said to the Euphrates 600 m.; its total area
approximately 1,200,000 sq. m.

GEOGRAPHY

_General Features._--In general terms Arabia may be described as a
plateau sloping gently from south-west to north-east, and attaining its
greatest elevation in the extreme south-west. The western escarpment of
the plateau rises steeply from the Red Sea littoral to a height of from
4000 to 8000 ft., leaving a narrow belt of lowland rarely exceeding 30
m. in width between the shore and the foot-hills. On the north-east and
east the plateau shelves gradually to the Euphrates and the Persian
Gulf; only in the extreme east is this general easterly slope arrested
by the lofty range of Jebel Akhdar, which from Ras Musandan to Ras el
Had borders the coast of Oman.

Its chief characteristic is the bareness and aridity of its surface;
one-third of the whole desert, and of the remainder only a small
proportion is suited to settled life, owing to its scanty water-supply
and uncertain rainfall. Its mountains are insufficient in elevation and
extent to attract their full share of the monsoon rains, which fall so
abundantly on the Abyssinian highlands on the other side of the Red Sea;
for this reason Arabia has neither lakes nor forests to control the
water-supply and prevent its too rapid dissipation, and the rivers are
mere torrent beds sweeping down occasionally in heavy floods, but
otherwise dry.

The country falls naturally into three main divisions, a northern, a
central and a southern; the first includes the area between the Midian
coast on the west and the head of the Persian Gulf on the east, a desert
tract throughout, stony in the north, sandy in the south, but furnishing
at certain seasons excellent pasturage; its population is almost
entirely nomad and pastoral. The central zone includes Hejaz (or Hijaz),
Nejd and El Hasa; much of it is a dry, stony or sandy steppe, with few
wells or watering-places, and only occupied by nomad tribes; but the
great wadis which