1012 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [TI2] 
spat in certain localities and the local currents in such places, and to 
submit them to the greater experience of these gentlemen who were 
better acquainted with the Eastern Scheldt. After we had consulted 
with these gentlemen as to the best way of making the desired observa- 
tions, and had visited various points on the Eastern Scheldt, on the 16th 
of August, with them, we felt that we must-no longer trespass on their 
time, when (as mentioned above) we were gladdened by the letter from 
the minister, during the latter part of August. We intend to embody 
the results of these investigations in our final report as soon as they 
have been communicated to us. It is hardly necessary to say that, as 
long as we are not in possession of these results (we hope to receive 
them during the first months of the year 1882), no connection can be 
traced between them and the facts mentioned in this report, and that 
we cannot attempt to draw up a plan for the observations to be taken 
on the oyster beds during the following years, but that nevertheless we 
may entertain the hope that we may come to know some of those gen- 
eral laws which govern the distribution of the oyster in this and other 
localities. 
We have still to report our observations on the temperature and den- 
sity of the sea water. Prof. Buys Ballot, Director of the Meteorologi- 
cal Institute, told us that, if such observations taken at different points 
of the Scheldt were to be really valuable, they must be taken three 
times a day, at high water, low water, and at 2 p. m., by the sun-dial, 
when the heat of the sun is supposed to have exercised its most power- 
ful influence. In reporting such observations it should also be men- 
tioned what the state of the weather was at the time, as rain and wind 
may have a considerable influence on the temperature and density of 
the sea-water. 
As regards the areometer above referred to, and manufactured at 
Utrecht by Mr. Olland, Prof. Buys Ballot advised us to get in addition 
one of the large areometers which are used by the German ‘‘ Commis- 
sion for the investigation of the German waters” in the German Ocean, 
and which are fully described and highly praised in their official report. 
The relative value of these different instruments could, however, only 
be ascertained by practically testing them in the observations which we 
had before us. Mr. Steger, of Kiel (Germany), furnished us this instrument 
as well as a set of areometers, which had also been recommended by 
the German commission. In using these instruments it has been found 
desirable to make some slight modifications, which were made by the 
engineer of the torpedo service No. I. 
Prof. Buys Ballot also advised us to use the maximum and minimum 
thermometers according to the Negrettt and Zambra system. As the 
water in the Eastern Scheldt is, comparatively speaking, not very deep, 
he thought it would be sufficient to observe the temperature of the water 
in the areometer, provided it is sufficiently thick and is drawn up quick 
4 
