(185 ) 
A systematical investigation of the normal and abnormal motions 
of the mean water-level, if extended over a large area and over 
some years, might prove of great importance with respect to two 
interesting problems. 
In the first place it would appear from such an inquiry that it 
will be always impossible to predict with great accuracy the absolute 
water-level at a given: place even when the periodic terms of the 
tidal components are fully known; therefore it can be of no use to 
carry on the calculations in behalf of tidal prediction to an astro- 
nomical degree of accuracy; in the second place an inquiry into the 
aperiodic departures from the average normal values might lead to 
a better knowledge of the important and varying meteorological 
influences which prevail on the ocean, than by means of the in- 
complete and scattered observations taken on board ship. 
It is not improbable that the variations of the water-level e.g. in 
the Gulf of Bengal and the Arabian Sea, which must be dependent 
on the “vis a tergo” in the Indian Ocean in and south of the area 
of the trade-winds, might give a clue to the prediction of the periods 
of drought to which the climate of India is subject. 
f. In recapitulating the results obtained, it must be kept in 
mind that the zero-point of the tide-gauge is on the upper end, so 
that low figures denote high water. If positive numbers are to 
correspond with high, negative numbers with low water, the argu- 
ment of the formulae must be augmented or decreased by 180° and 
the corrected monthly values subtracted from an arbitrary number. 
After reduction to the conventional origin of time, application of 
the augmenting factor WR to the amplitudes of the annual variations, 
reduction to average values of the constants in so far as they are 
dependent on the moon’s declination and, finally, inversion of the 
sign, the following tidal constants are found for Telok-Betong: 
Telok Betong. Java’s 4th Point 
H x H x 
Si 2.7 em. PA Oa — — 
So 13.7 262° 12.8 c.m. 280° 
Ms 32.1 222° 24.2 210° 
Ky 15.5 269° 6.8 226° 
O 7.8 265° 3.4 216° 
d= 4.2 231° Lee Tel? 
N 5.6 192° 4.1 190° 
Ky 5.3 246° 2.5 299° 
Sa 5.6 263° 1.4 220° 
Ssa 9.5 120° 5.6 149° 
W Eins 53.9 
