70 AUSTEALASIA. 



known, at least in their outward aspects, than many regions of Eastern Europe. 

 But on the other hand the interior of several islands is delineated on our maps, 

 not from accurate surveys, but from incomplete itineraries or vague native reports. 

 Nevertheless, the geodetic network is gradually spreading from island to island 

 across the Malay lands, and sooner or later the whole of the archipelago will be 

 represented with the same accuracy and minuteness of detail as Java and some 

 parts of Sumatra and even of Celebes, which are already figured on excellent 

 topographical and geological charts. Meanwhile, as to the population, it is still 

 impossible to give even a rough estimate of the actual numbers for the whole area. 

 The official statistics distinguish for the different islands the number of inhabitants 

 returned by the regular census, a systematic calculation or a more or less plausible 

 estimate. Lastly, there are regions for which not even a conjecture can be hazarded. 



Climate of Indonesia. 



The Sunda Islands lie within the zone of the alternating trade winds and 

 monsoons. But the normal course of the aerial currents is constantly modified by 

 the shifting of the centres of attraction due to the returning seasons and to local 

 phenomena. At Batavia, taken as the headquarters of the hundred and fifty-one 

 meteorological stations scattered over the Archipelago, the "good monsoon," that 

 is, the south-east trade wind, prevails during the northern summer months, and 

 especially from June to September. At this time the atmosphere is usually drier 

 than during the " bad monsoon," which mainly comprises the period from 

 December to March, when a much larger quantity of moisture is precipitated. 



Nevertheless, this contrast of the seasons is not always very sharply defined, 

 especially in the interior of the large islands. No month is altogether rainless, 

 and even during the so-called dry season the atmosphere along the seaboard is 

 charged with 80 per cent, of relative humidity, while during the rainy season 

 it is nearly at the point of saturation. For the whole of Indonesia the mean 

 rainfall, according to Voyeïkov, exceeds 120 inches. But in many regions it 

 is verv difficult to distinguish the true alternation of the seasons, and form a 

 correct idea of the normal succession of wet and fine weather. Even to the east 

 of Celebes the moisture is brought chiefly by the south-east trades, while the west 

 monsoon is accompanied by clear skies. In a shifting and uncertain zone between 

 Sumatra and Timor the two opposing currents are, as a rule, accompanied by about 

 an equal quantity of moisture. On the other hand, in the endless labyrinth of 

 islands, the normal direction of the lower winds and marine breezes is modified by 

 every strait and streamlet. 



In a vertical direction also — that is, ascending from the sea-level to the 

 mountain tops — considerable changes are observed in the general course of the 

 winds. The western monsoon affects the lower atmospheric masses only, its 

 thickness never exceeding 6,500 feet. Hence its force is mainly felt about the 

 foot and lower slopes of the hills, as for instance at Buitenzorg (920 feet) in the 

 western part of Java. In this district, one of the most abundantly watered in the 



