660 
BULLETIN OF THE BUBEAU OF FISHERIES 
that separates Cape Cod from Stellwagen Bank was responsible for this unexpected 
warmth of the bottom water at the tip of the cape. 
The facts that the inshore stations for the last week of February were slightly 
warmer at all levels than they had been three weeks previous, and that the water 
was slightly warmer inside Gloucester Harbor (2.78°) than a mile or two off the 
mouth (2.2°), instead of the reverse, are sufficient evidence that the coastal belt had 
begun to gain heat from the sun faster than it was losing heat by radiation from its 
surface. This gain was not yet rapid enough, however, to have produced any general 
differentiation in temperature between surface and underlying water in the moderate 
depths of Massachusetts Bay; and periods of severely cold weather may be expected to 
cause temporary reversals during the first weeks. In fact, a setback of this sort seems 
Fig. 85. — Temperature at tbree representative stations (5, 10, and 18 to 18A) in the southern side 
of Massachusetts Bay on January 0 and 7, 1925 (solid curves), and on February 6 and 7 
(broken curves), to show change in one month 
to have occurred between the 25th and 27th of that February, because the Fish Hawk 
once more found the water off the mouth of Plymouth Harbor coldest at the surface 
on the latter date, after three days of severe cold accompanied by a northwest gale 
Thus, the shoals seem to have acted as a temporary center for cooling there, as 
might be expected. 
The winter of 1912-13 seems to have been about as cool as 1924-25 in Massachu- 
setts Bay, minimum temperatures slightly higher (2.8° at surface and at 46 meters, 
3.11° at 82 meters, February 13, 1913) being associated with the situation of the 
standard station well out in the mouth of the bay. February, 1921, was measur- 
ably warmer, with 3.3° at the surface, 3.52° at 20 meters, and 3.63° at 40 meters ljH> 
