176 TREUBIA VOL. II, 2—4. 
Again I could notice that before October 15th, in connection with the fact 
that, owing to the tides not rising high enough, hardly any water could 
be admitted from the sea, measures had been taken to admit water from 
the land-side into the ponds A and B of Map Il from the Muara Karang, 
which caused the salinity of the water in these two ponds to diminish 
a little after September 24th. 
It was not until after October 28th and before November 18th (a 
therefore as appears from Diagram I about November 6th) that it prove 
feasible to admit so much sea-water as to lower the salinity considerably 
in all the ponds except in the small fry-ponds C. The water admitted 
from the landside from the Muara Karang had a salinity of 32.3 % 
on November 18th. We may therefore state that in 1918 the flood-tides 
had to reach at least the level of the spring-tide of November Oth, or slightly 
more than the level of the spring-tide of April 28th, before considerable 
quantities of sea-water could be let into Mr. Görs’s ponds dealt with here. 
The fact that the canals through which the sea-water has to be led to 
the ponds are but narrow, that they silt up soon, especially their mouths, 
and that they are not always perhaps dredged out sufficiently and in due 
time, is of course not without significance for this problem. 
As we have already seen, in 1918 the salinity in six ponds reached its 
maximum between October 28th and November 18th. In pond B of Map II 
this maximum was reached already before October 15th, in the fry-ponds C 
only after November 18th, 
This decrease of the salinities in October, November and also in Decem- 
ber 1918, was dependent almost exclusively on the possibility of admitting 
sea-water towards the end of the year when the floodtides rose higher. 
The effect of the West-monsoon rains was not noticeable till after 
February 4th, but then very markedly, as we shall see below from an 
other series of observations (cf. Table IV). On the 10th of February 1919 
the salinity in the most landward ponds was still a little higher than in the 
ponds nearest the sea. When on April 17th next | came once more in the 
pond-system of Mr. Görs, this was no longer the case. So then the last 
trace of the high salinities that developed during the East-Monsoon (the dry 
season) of 1918 had disappeared. In 1919 the decrease of the salinities in this 
pond-system continued at least till July 2nd. On August 12th following, evapo- 
ration, under the influence of the regular prevalence of the East-monsoon dry 
winds, had acted so powerfully again, that in the fry-ponds C and C’ salinities 
were once more found surpassing those of the sea-water on the beach. 
Then in October and especially in November 1919 higher salinities of up- 
wards of 40°/,, to 74.5°/), begin to appear again everywhere. | even ascer- 
tained the occurrence of salinities as high as 81°/,, and 93.2°/,, in the 
fry-ponds C, on the 20th of October and the 4th of November 1919 
respectively. However, at the time when I observed these extreme salinities, 
these fry-ponds contained no fish. 
