50 



bulletin: museum of comparative zoology. 



chusetts Bay in the first half of July, (Station 2 ^) shows (fig. 8, 11) that 

 there is a very rapid decline in temperature from the surface where it 

 is about 65°, to 49° at about ten fathoms, followed by a rather slower 

 decrease to 40.3° at about thirty-five fathoms, from which point down- 

 ward to the bottom there is no further change. In the shallower parts 

 of Massachusetts Bay in July, Stations 5 and 6 (fig. 9) the cooling 

 between the surface and ten fathoms is even more rapid, the drop 

 being from 61° to 43.4°; and it then declines less rapidly just as at 

 Station 2, to the bottom in twenty-thirty fathoms, at which point the 

 lowest temperature, 41.3° is reached, the temperature at this level 



Fig. 11. — Temperature sections in the mouth of Massachusetts Bay (Station 

 2), and west of Jeffrey's Ledge (Stations 11, 14). 



being the same as it was at Station 2. In the Bay at the end of 

 August conditions are different, as pointed out below. At Station 1 

 the temperature curve is practically the same as at Stations 5 and 6, 

 the temperature at the bottom in thirty-five fathoms being 40.6°, 

 very nearly what it is at Station 2 at a corresponding depth. 



The section in the 100 fathom basin off Cape Ann, Station 7, 

 (fig. 10) shows that the surface layer of warm water was slightly 

 thicker here, the drop from the surface to 10 fathoms being only from 

 64° to about 53°; and the rate of decrease diminishing slowly until 

 the minimum of 40.3° is reached at fifty fathoms, instead of at thirty- 



1 To agree with the station numbers of the U. S. Bureau of Fisheries 10000 

 should be added to the numbers given in this report, e. g. 10002. 



