"كتيّب الجزيرة العربية. المجلد I. ١٩١٧" [‎٢‎٠‎٠] (٧٤٨/٢٠٩)

200
ADEN AND THE INTERIOR
of Sheikh 'Othman and small village of Hiswahon the north-east, at
a radius roughly of ten miles from Aden town. The island of
Socotra, in the Arabian Sea, passed under the protection of the
British Government in virtue of a treaty concluded with the Sultan
of Mahrah in 1886 (p. 205).
The peninsula of Aden proper is an irregular oval, 15 miles in
circumference, with a diameter of from 3 to 5 miles, connected with
the mainland by a neck of land about 1,350 yards wide, but at
one place nearly covered at high spring tides. The causeway and
aqueduct, however, are always above, although at some seasons
only just above, water level. The peninsula consists of a huge crater
walled round by precipices, the highest point being 1,775 feet above
the sea ; and rugged spurs, with valleys between, radiate from the
centre. A great gap in the circumference of the crater has been
rent on its eastern sea-face by some later volcanic disturbance.
The town of Aden and part of the military cantonment lie within
the crater, and consequently are surrounded on all sides by rocky
hills. Lavas, spongy breccias, and tufas form the materials of this
volcanic -fortress. The natural vegetation is very scanty and
resembles that of Arabia Petrsea.
The average shade temperature of Aden is 87°—the mean monthly
range being from 75° in January to 98° in June, with occasional
variations up to or exceeding 102°. The lulls between the monsoon
periods, in May and September, are specially oppressive. The
mortality among Europeans, although greatly increased by the sick
or dying from the passengers and crews of ships, amounts to only
7*2 per thousand. Aden, in fact, ranks as a rather healthy station
for troops, though on first arrival they are subject to sandfly-
fever, and it is a well-ascertained fact that long residence impairs
the faculties and undermines the constitution of Europeans.
The climate during the north-east monsoon, or from October to
April, is cool and pleasant, particularly in November, December,
and January. During the remainder of the year (the period of the
south-west monsoon), hot sandy winds, known as (north),
prevail within the crater, but on the western or Steamer Point side
the breezes come directly off the sea and are fairly cool. The
rainfall may be said to vary from J inch to 8| inches, with an
irregular average of about 3 inches ; the irregularity and smallness
of the yearly rainfall is borne out by the fact that the tanks, since
their restoration in 1856, have only been filled six times—in May
1866 and 1870, and September 1877, 1889, 1893, and 1897. The
Settlement is exceptionally free from infectious diseases and epi
demics. The absence of vegetation, the dryness of the soil, and the