459 
the opposite occurs. The difference namely of the barometric devia- 
tions at Batavia and Singapore changes in an irregular manner and 
points to a transitional region between these two places, whereas the 
difference between the deviations at Port-Blair (Andaman Islands), 
and those observed at Singapore, runs parallel with the barometric 
deviations at Port-Darwin, although with a small correlation (r==0,15). 
While the atmospheric pressure goes through its 3 to 5-yearly 
cycle, during the maximum in the South, Middle and East air- 
currents from the South would be superposed on the general flow 
of the monsoon and in the North-East, although to a smaller extent, 
from the North and currents from opposite directions during the 
minimum. Between the two currents a rising or falling movement 
should appear. The predominant positive correlation during the whole 
year in the Padang Highlands and in group 8 (Pontianak and Sing- 
kawang), which are approximately situated on the border line, might 
be a consequence of this vertical movement of the air. The corre- 
lation factors in the North-western exceptional region are small 
however, so that not much importance must be attached to these 
speculations. 
Nor can we expect much for this region in the way of predictions, 
at any rate on the lines here developed. Matters are quite different 
for the remaining part of the Archipelago, where the correlation under- 
goes regular changes and reaches fairly considerable values. 
The great question thus remains how we can obtain sufficient cer- 
tainty about coming changes in the atmospheric pressure. Very likely 
we shall have to pay less attention than was done until now to the 
sun and the changes occurring there, but we shall have to look 
especially for a terrestrial cause and shall have to study the coope- 
ration of metereological phenomena over the whole world. 
For the temperature changes, observed in British India, the Archi- 
pelago and Australia find a natural explanation from the fluctua- 
tions in the general circulation of the atmosphere, accompanying the 
barometric changes, while it is difficult to bring them into relation 
with changes in the solar radiation, which surely would reveal 
themselves in a direct manner in temperature changes. 
These temperature changes are of a twofold nature: 
1. In this tropical region, where long-period changes in the 
atmospheric pressure are brought about not dynamically, but enti- 
rely thermally, these must be accompanied by simultaneous tem- 
perature changes of opposite sign in the air-column above the 
spot of observation. In agreement with this we find e.g. from a 
comparison of the changes in atmospheric pressure at the mountain 
