660 



BULLETIN OF THE BUEEAU 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 three representative stations (5, 10, and 18 to 18A) in the southern side 

 of Massachusetts Bay on January 6 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 HawTc 

 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 IJ^ 



