244 MARINE BIOLOGICAL LABORATORY. 



ments of the currents, tides, winds, etc., all affect the 

 changes which occur to such an extent, that they must 

 be studied simultaneously and over a considerable area, 

 and also during the various seasonal changes before any 

 adequate idea can be obtained of even the limits of the 

 problem. 



The physical, mechanical, and chemical changes which 

 take place are all the result of the operation of laws, 

 which are so complicated in their action and interaction 

 that their study in combination becomes an interesting 

 as well as profitable occupation. 



If some relation could be found to exist between the 

 meteorological conditions upon the land (which are being 

 constantly observed and discussed) and the changes 

 which occur in the bodies of water, the information 

 would be of the greatest service to our fishermen. It 

 would prevent many fruitless searches for schools of 

 fish in regions unfitted by the temperature of the water 

 for the distribution of the food of these fishes, and 

 consequently of the fish themselves. As the tempera- 

 ture of the water, doubtless, controls this distribution, a 

 systematic study of the various causes of its changes, 

 and the means by which they are brought about, be- 

 comes an eminently proper subject for investigation. 



Thus a definite object has been kept in view in the 

 prosecution of the physical inquiries of the Commission. 

 This became necessary as the work of the Commission 

 developed. At first it was quite right that the investi- 

 gations should be experimental and tentative, and only 

 as the problems assumed shape could some positive 

 object be given to each research along definite lines, 

 with the view of uniting the results into a studied 



