22 AUSTEALASIA. 



West of Borneo and the Philippines the meteorological conditions are again 

 modified by the differences in the outlines and elevations of the great insular 

 masses. Here mariners no longer speak of trade winds, and recognise the 

 monsoons alone. That of the south-west, sweeping over the Sunda Strait and 

 Sumatra, prevails somewhat regularly from the middle of April to the middle of 

 October, in the more open waters stretching away to Formosa. But it is occasion- 

 ally interrupted by the south-eastern winds, and on the insular and continental 

 seaboards its course is fringed b}^ lateral breezes, eddies, and back- currents, which 

 enable sailing craft to beat up against the monsoon. 



This south-west wind which prevails in summer is followed in winter by the 

 north-east monsoon, which is in fact the normal polar current. Like the south- 

 west monsoon it blows throughout half the year, although most intensely in 

 December and January. Both seasons are accompanied by rains, as well as by 

 sudden gales and storms. But the terrific cyclonic movements of the China Sea, 

 here known as typhoons, that is, tai fang, or " great winds," occur chiefly during 

 the south-west monsoon in June or July, or else towards the September equinox 

 when the normal annual currents are reversed. These fierce whirlwinds, which 

 are generally developed in the east, move with spiral action in the direction of the 

 west or north-west. They are usually more intense in the vicinity of the land 

 than on the high seas, and fall off rapidly towards the south. Hence the 

 typhoons rarely extend their range towards the equatorial regions in the waters 

 stretching south of Luçon, largest of the Philippine Islands. 



Beyond the Sunda Archipelago, that is, in the ojoeu space presented by the 

 Indian Ocean as far as the Mascarenhas and JNIadagascar, the winds are less 

 influenced by insular or continental seaboards, and consequently here acquire a far 

 more regular course. The zone of the south-east trades, which occupies the 

 section of the ocean comprised between Australia, Madagascar, and the equator, is 

 uniformly displaced northwards and southwards according to the alternation of the 

 seasons themselves. Thus it is shifted to the north of the equator with the 

 movement of the sun towards the northern hemisphere, while at other times its 

 range seldom extends much beyond the 5" of south latitude. 



Bui, round about the central part of the ocean, dominated by the regular 

 system of the south-east trades, there stretches the vast semicircle of lands between 

 South Africa and Australia, which are fringed by a zone of alternating monsoons 

 setting landwards during the hot and seawards during the cold season. In no 

 region of the globe have the monsoons a more regular course than in the northern 

 section of the Indian Ocean between Somaliland and Sumatra. The south-west 

 monsoon with its escort of thunderstorms and rains prevails from the middle of 

 April to the middle of September throughout the Arabian Sea and the Bay of 

 Bengal. It is followed by that of the north-east, that is, the polar current, which 

 lasts from the middle of October to the middle of March. But in the southern 

 hemisphere the atmospheric system is less regular on the coasts of Australia, 

 Madagascar, and the African mainland ; nor is the contrast between land and 

 water so sharply marked in this region. Here also, as in the China Sea, the clash 



