PHYSICAL, OCEANOGRAPHY OF THE GULF OP MAINE 579 



Temperatures (°C.) 17 miles southwesterly from Cape Fourchu in 1907, from Dawson {1922, p. 8S) 



The source of this cold indraft is found near Cape Sable — by Dawson's records 

 10 miles south from Brazil Eock on the 26th and 27th, quoted below^which also 

 shows an interesting variation in temperature at different stages of the tide. 



Temperatures (°C.) 10 miles south of Brazil Rock (from Dawson) 



Depth 



June 26, 

 high 

 water 



June 27, 



low 



water 



Surface—. 

 9 meters.. 

 18 meters 

 27 meters. 

 66 meters 



8.6 

 4.7 

 2.8 

 2.6 

 1.4 



7.8 

 7.6 

 17 

 3.9 

 1.9 



It is probable that when belated overflows of the cold Nova Scotian water into 

 the gulf do occur after early June they are of brief duration, for we have found no 

 evidence of such an event later in the season on our recent cruises. 



Dawson's June temperatures likewise afford an interesting illustration of the rate 

 at which the surface water may be expected to warm along the Nova Scotian coast 

 sector between Yarmouth and Cape Sable during the month of June. Thus, the 

 surface there was 4.4° to 5° on the 7th of the month ia 1904, though it had already 

 risen to 6° at the mouth of Yarmouth Harbor by that date. In 1907 the surface 

 was 5° to 6° in the offing of Yarmouth on the 11th to 15th; 6° to 7.8° on the 22d 

 (warmest close in to the land) ; 6.5° to 8° to the eastward of Cape Sable by the end 

 of that month; but the tide-swept region close to the cape was still only 4.2° to 5°, 

 and this cold pool reappears on our charts for August (p. 592) . 



In 1915 the temperature of the surface water had risen to 10° over Browns Bank 

 and the Eastern Channel (stations 10296 and 10297) by June 24 to 25, which is 3.5° 

 cooler than the expectation for Massachusetts Bay at that date, and the water that 

 filled the trough of the channel at depths greater than 100 meters was about 1 to 2 

 degrees warmer (7° to 8°) than on April 16, 1920 (station 20107). On Browns Bank, 

 too, the temperature of the bottom water was about 4° higher at the June station 

 than at the April station (stations 10296 and 20106), but the 40-meter reading 

 was actually lower in June (2.8°) — colder, iu fact, than any June reading in the iuner 

 parts of the Gulf of Maine. The presence of a cold mid stratum at this particular 

 locality sandwiched between water of 7.36° on bottom at 80 meters, 10° at the 

 surface, is unmistakable evidence of an extension of the cold Nova Scotian water 

 from the eastward out over the bank, indenting into the higher temperatures that 



