BIGELOW: EXPLORATIONS OF THE COAST WATERS. 



219 



perature as a whole was lower along this line as well as over the 

 slope, in June than in the preceding August, as might have been 

 expected ; while had it not been for solar warming of the previous few 

 weeks, the surface would doubtless have been nearly as cold as the 

 60 meter-level, as is probably the case in winter. But in June this 

 cold Cabot Current water has no apparent effect on the temperature 

 of the Gulf at any depth, there being a sudden transition in the North- 

 ern Channel and over Brown's Bank from the low temperatures (2.°) 

 of the one to warmer water of the other (Fig. 56, 57). 



Fig. 62. — Salinity at 40 meters, May, 1915. 



Judging from the experiences in past years, the temperature of the 

 upper layers had probably passed its midsummer maximum and 

 autumn cooling had commenced by late August, and early September, 

 when we made our third oceanographic cruise in 1915, as is illustrated 

 by comparing the surface temperatures for July and August, 1914 

 (Fig. 1) with the chart for September 1915 (Fig. 58). But while the 

 western part of the Gulf had cooled by about 2°, cooling had not 

 penetrated downward to any distance, for the 40 meter-level (Fig. 59) 



