( 186 ) 
Besides the constants for Telok-Betong these quantities are given 
also for the tidal station Java’s 4% Point, situated too in Sunda- 
strait; they have been computed from a five-year series of observations. 
A comparison between the data for the two places exhibit some 
important differences, whilst a look at the chart would show that 
their situation with respect to the tidal wave, progressing from the 
Ocean in the strait, is about the same. 
For the differences of time, Telol:-Betong minus Java’s 4 Point, 
we find: 
Sz — 18° = —0.6 hours. 
My -+ 12° = 0.4 » 
Ky + 43° = 2.9 > 
O + 49° = 9.9 » 
The single diurnal tides in the Lampong-bay therefore lag behind 
those near Java's 4% Point in quite another way than the moon’s 
semi-diurnal tide My and this again in another way than the semi- 
diurnal solar tide S,, which is in advance. 
An estimation of the tides for the one place based on those of 
the other by assuming a constant difference of time — as is usually 
done along a coast — is therefore quite inadmissable here, as 
the differences of time are by no means constant, but variable 
according to the moon’s phase and declination. 
If we look at the hindrance which Sumatra’s most southerly neck 
of land offers to the free propagation of the mono-diurnal tide-wave 
from the Java-sea into the Lampong-bay, we should expect a stronger 
influence of the K, wave near Java’s 4 Point than on the road 
of Telok-Betong, but, on the contrary, the tide near the latter place 
may be regarded as twice as “monodiurnal” as the tide in the 
strait, as in shown by the proportion: 
Ampl. —~———_ == 0,51 near Telok Betong, 
— 0.28 near Java's Ath point, 
Pp 
This prevailing influenee of the Java-sea on the tides in the bay 
does not, however, give an explanation of the peculiar fact, that the S> 
tide in the bay causes high water earlier than in the strait proper, 
whereas the other tides occur later. 
If we assume that the S, wave finds its way into the bay in the 
same way as the other waves, it ought to have rather a retarding 
effect, because near Duizend-eilanden the kappanumber of Sg is ELS 
