1065 
periods appear could not be predicted and one would always be 
uncertain whether the end of a regular series is near. Fortunately 
however these disturbances seem to be anything but irregular in 
their appearance, so that there exists a possibility of announcing 
them in advance. This may be seen from the comparison of the 
barometercurve I with the curve II, which represents Wo1r’s relative 
numbers of sunspots. Jt is remarkable that the disturbances in the 
barometercurve coincide with the maxima of the sunspotcurve, whereas 
during the periods with small sunspot intensity the regular barometric 
wave is developed undisturbedly. 
It cannot be denied that the number of sunspot periods over which 
this comparison is possible, is but small, however there seems to 
be every reason to suppose that we have here to do with a real 
and not with an accidental connection. Indeed it is a matter of fact 
known already since Jong that there exists a connection between 
the number of sunspots and different meteorological phenomena, 
and the above mentioned result agrees with what has been found 
in earlier researches. At the close of this communication this con- 
nection will be still further considered. 
One would be inclined to go back, beginning with the year 1876 
and examine still more closely the connection between sunspots and 
disturbed barometerperiods by means of the observations made at 
other stations with longer records. For this purpose i.a. the stations 
Batavia, Adelaide, Bombay, and Madras would be adapted. As 
however at these stations the oscillation itself is less regular, it is 
very difficult to distinguish what is disturbed by the sunspots and 
what is not, and the results would not be very convincing. 
Now the question arises how the rainfall is affected with regard 
to the barometer oscillations. In answering this question the disturbed 
periods in whieh the connection is less distinct will be left out of 
account and only the regular waves will be considered. In curve V 
the rainfall deviations in West-Java (6 ‘monthly means, calculated in 
the same manner as the deviations of curve I, accordingly reduced 
to one month) have been represented monthly ; for the years 1875— 
1878 the curve is based on the Batavia observations only. 
The curve shows clearly that the connection between rainfall and 
airpressure is different in the West- and the Eastmonsoon, it may 
serve to illustrate the numbers which are given below. 
The investigation may be divided into three parts according to 
the schematic barometer curve. 
1. The Eastmonsoons of the years in which the barometer is 
moving from maximum to minimum; these are years of transition. 
