SUNIER: Marine fish-ponds of Batavia. 167 
such as those of KüCHLER, on board the Valdivia amounted to 0.2 °/,9, 
on board the Danish lightships to 0.27 °/,). The largest error in salinity- 
determinations by means of KiiCHLER areometers, found by the investigators 
of the Scripps Institution in California, amounted to about 0.32 °/,, (43). 
In 1915 Mr. P. C. VAN KOESVELD, the captain of the Government 
Investigation Steamer “Brak”, and myself determined, with a KiiCHLER 
areometer, the salinity of two samples of sea-water, each divided into 12 
portions, The temperatures of the different portions, which had been kept 
for some time near the hatches of the engine-room, were rather various. 
As a result, the areometer-readings naturally varied also, so that the observer 
could not know, already after the first 3 or 4 readings, how high he might 
beforehand expect the following areometer-readings to be. Now the values 
found for the salinities varied as follows: 
Ist sample. 2nd sample. 
STONE SANS ES 
SJ HOME 3434 go 
Sal 20%, 54.32, 0, 
SMOS SS | 200 
SOAs SHS Olas 
SOZ 3423 ee 
SON OS 3422400 
067000) SANS) ES 
SLO Seed Olas 
See 1260 Sey So, 
OSE OS S414 so 
33a, Oley ZAND 
The greatest difference found between the salinity of any two portions 
of the same sample of sea-water was therefore in the first case 0.315 °/,, 
and in the second case 0.245 oo. 
Further I found 32.4 °/,,, by means of a KüCHLER areometer, for the 
salinity of one half of a sample of sea-water, which I caused to be taken 
on the beach just west of the Old Harbour Canal of Batavia, at hieh 
tide on October 21st 1918. Mr. K. M. VAN WEEL, our hydrographic 
assistant, determined by MOHR’s titrimetric method the amount of chlorine 
of the other half of this sample. The salinity, according to the tables of 
KNUDSEN ('°), belonging to the amount of chlorine found, was 32.52 |... 
The discrepancy in the results of the two methods as applied to the same 
sample of sea-water, therefore amounted in this case to 0.12 %/yo- 
Moreover at the end of 1915 DR. A. WUNDERLICH of the Commer- 
cial Laboratory (Handelslaboratorium) at Buitenzorg, determined with a 
pyenometer the specific gravity of three portions of the same sample of 
sea-water, which specific gravity was also determined by the captain of 
our Investigation Steamer and myself by means of a KUCHLER areometer. 
The result may be tabulated thus: 
