1014 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [14] 
(4.) To find whether there is any connection between the settling of a 
greater and smaller quantity of oyster spat and the following: 
a. The nature of the bottom. 
b. Phenomena of the current. 
ce. Changes in the temperature of the water; and, 
d. Changes in the density of the water. 
These four points, which are here given in the order in which the diffi- 
culty of their explanation increases, give an outline of the problem, the 
solution of which we are seeking. The fourth point at the same time 
indicates what results long-continued and carefully made comparative 
observations may possibly lead to. These results, however, will, in our 
opinion, not be reached in the near future, although we feel convinced 
that any positive results in this direction will not only be of importance 
to oyster culture in its present state, but will also serve as a guide in 
exploring other localities, where in former years profitable oyster fish- 
eries were carried on, which at present have entirely disappeared. 
From the causes already referred to we are stillless able to return an 
answer to the question mentioned under No. 3. Our observations of the 
temperature and density of the water are as yet not numerous enough, 
and in some respects not reliable enough, to justify us in basing upon 
them comparisons such as are there indicated. The observations with 
which we have been occupied during the past sumraer are principally 
those mentioned under Nos. land 2. As has been said before, we were 
obliged not only to determine the respective value of our different in- 
struments, but also to endeavor to arrive at some definite result as to 
the manner in which long-continued observations of this kind should be 
regulated—who should take such observations, and how they should 
betaken. Knowing that we could only spend a few short summer months 
in the localities where the observations must be taken, and fully aware 
of the great importance of obtaining full data also from other seasons 
of the year (especially autumn and spring), we made inquiries of a num- 
ber of oyster cultivators, whether among their employés suitable per- 
sons could be found who would permanently take charge of these obser- 
vations, and thus furnish us with the desired data. From different 
parties we obtained highly valuable aid in this respect. In the first 
place we must here mention Mr. Wagtho, of Tholen, who took observa- 
tions during the whole summer, and still continues to do so; further- 
more Messrs. ’. Leo de Leeuw, of Wemeldinge, C. L. de Meulemeester, of 
Bergen op Zoom, and the watchmen of the firms of Hagan & Brand and 
Bolier & de Groot. All of their observations, taken during the past 
year, have been tabulated, and will be appended to our first report in 
that shape. We shall, as a matter of course, in continuing these obser- 
vations, have to rely on the active co-operation of the oyster cultivators. 
‘The importance of their aid cannot be overestimated, and the results of 
such observations will undoubtedly gain in value, if based on a broad 
basis of facts, carefully and patiently gathered during a long period of 
