OCEAN TEMPERATURES AND CURRENTS. 249 



have been made upon the atmospheric conditions, atten- 

 tion paid to wind velocity, tidal movements, and also to 

 the direction and velocity of the currents. This light- 

 ship occupies the most exposed position upon our coast, 

 being twenty-one miles southeast of the island of Nan- 

 tucket, and affords a fine opportunity for the study of 

 these phenomena. 



Many interesting results are expected from this inves- 

 tigation, which, while they will be of scientific value in 

 other directions, will be welcome sources of information 

 to aid in the solution of the problems of the Fish Com- 

 mission. 



The physical investigations in Long Island Sound can 

 be described in a few words. 



For several years a decrease has been noticed in the 

 oyster crop from that body of water. At first it was be- 

 lieved that the natural enemies of the oyster, such as 

 the star fish, the drills, etc., were the main cause of the 

 evil. After investigation it was seen that where the 

 oyster beds were properly cared for, their enemies did 

 not exist in sufficient numbers to cause the trouble, 

 though the oysters continued to disappear from these 

 beds, masses of empty shells being brought up in the 

 dredges. While the Fish Commission steamer Fish 

 Hawk was investigating this matter last year, they 

 occasionally brought up in their dredge great quantities 

 of decomposing matter, which was so offensive that it 

 had to be instantly washed back into the water. It 

 should be remembered that for several years past the 

 river mouths and harbors along the Sound have been 

 dredged, and the matter obtained dumped into the 

 deeper portions of the Sound ; and further, that the 



