The China Sea directory - Sabrizain.org

CHAP. III.] WINDS AND WEATHER. 153
directly on shore ;
north-westers, with few exceptions, are the only winds
that blow with violence. Westward of the outlying islands the winds are
from S.S.E. to S.W. The rainy season ends in August.
South of the Equator.—From October to April the N.W. monsoon
of the Indian Ocean prevails on the west coast of Sumatra south of
the equator, and is ushered in by thunderstorms and heavy rain. Land
and sea breezes are occasionally experienced, and bad weather with rain
and heavy squalls occur at night. Near the equator the winds are
variable with frequent calms.
During the period from May to September the S.E. trade wind prevails
on the west coast south of the equator, and blows from S.S.13. to S.S.W.
with fine weather. In this season N.W. winds with bad weather are
occasionally experienced at full and change of the moon. Land and sea
breezes occasionally blow in May and September.
Cyclones, occur in the South Indian Ocean between the months of
November and April, but none are recorded as being met with on the west
coast of Sumatra. The nearest approach is one noted in November 187l,
at about 100 miles S.W. of the Pagi islands. In July the same year (a
most unusual period) one is recorded at 300 miles westward of Siberut
strait, thence taking the usual westerly direction. No others are recorded
within 500 miles of the coast. They are not unknown at the Keeling
islands.* See page 226.
CURRENTS.—On the west coast of Sumatra the current is influenced
greatly by the winds, and seldom runs to the northward, in either
monsoon, except when the wind is blowing strong from southward. When
N.W. winds prevail, the current runs with the wind to the S.E., and it
generally sets in this direction along the coast in both monsoons particu-
larly in north latitude, but seldom exceeds 12 to 18 miles a day. To the
northward of the equator, when the current is setting to the southward
betwixt the coast and the islands, it is frequently at the same time running
to the northward in the open sea, far outside of them.
In October, November,, and December, it is often tedious getting to the
northward, particularly from the equator to Aehi head, for baffling N.W.
winds and southerly currents are often found to extend a considerable dis-
tance from the coast in these months, particularly in the channels among the
large islands in the offing, where the current sets to the South and S.W.
but in June and July, between Analabu and Achi head, the current has
been found to set to the N.W. from 20 to 30 miles per day.
To the southward of the equator, when at times the southerly winds
blow with considerable strength from June to October, a drain of current
is impelled to the northward, at which time it is difficult to work to the
southward along the coast.
* See A'lmiraltj- wind and cureent charts.