832 BULLETIN OF THE BUREAU OP FISHERIES 



from Halifax, and one from Gloucester Harbor, where it was picked up on August 

 14.'' Although two of the bottles from this line drifted to Newfoundland, showing 

 a division, this does not detract from the evidence of the Gloucester recovery. 



Clearer evidence that the cold tongue that skirts Nova Scotia and flows past 

 Cape Sable into the Gulf in Maine in spring is actually an overflow from the icy 

 pool that develops from Cabot Strait out over Banquereau Bank, when the ice is 

 coming out of the Gulf of St. Lawrence, could hardly be asked than results from the 

 temperatures, salinities, and bottle drifts just discussed. 



I believe it now sufficiently demonstrated that while this cold pool (fig. 167) 

 owes its low temperature, to some extent, to the direct outflow of icy water from 

 the Gulf of St Lawrence via the Cape Breton side of Cabot Strait, it more directly 

 muTors the chilling effect of the field ice from the Gulf of St. Lawrence as this 

 melts in the region between Banquereau Bank and Sable Island. Consequently, 

 cold water that reaches the Gulf of Maine from the east is, in fact, ice-chilled, 

 though this takes place 300 miles or more to the eastward of the eastern portal to 

 the gulf. 



It is to this cold band skii'ting Nova Scotia that the name " Nova Scotian cur- 

 rent" is applied in the preceding pages. During the spring a large volume of water 

 enters the eastern side of the Gulf of Maine from this source, producing the efi'ects on 

 salinity and temperature described in the chapters on those physical features; and 

 this is certainly the chief source that contributes cold water of northern origin to the 

 Gulf of Maine — almost certainly the only source making a contribution of this sort 

 suflicient in amount and cold enough to exert any appreciable effect on the tempera- 

 ture of the gulf (p. 682). 



This current flows into the gulf in volume during only a few weeks in spring — 

 earlier in some years, later in others. As its fluctuations are referred to repeatedly 

 in the preceding pages a summary will suffice here. 



In 1920 (a late season) icy water (<1°) from this source had spread west- 

 ward as far as the offing of Shelburne, Nova Scotia, by the last week in March; but 

 neither the temperature nor the salinity of the eastern side of the Gulf of Maine give 

 any evidence that it had commenced to flood past Cape Sable up to that date, nor 

 do the isohalines for that April suggest any drift of water of low salinity into the gulf 

 from the east. The coastal zone, also, warmed about as rapidly in the one side of 

 the gulf as in the other during that month (p. 553). Conditions seem, then, to have 

 remained comparatively static off Cape Sable through the first two months of the 

 spring of 1920, and if the Nova Scotian current discharged at all into the gulf in that 

 yeai- this did not happen until May or later. In 1919, however, an early season, its 

 western expansion culminated before the last of March, and had slackened, if not 

 ceased, by the end of April (p. 568). In this respect 1915 seems to have been inter- 

 mediate (so may be taken as a representative spring), with the Nova Scotian current 

 exerting its chief chilling effect on the eastern side of the gulf before the first week 

 in May (p. 560), and slackening from May to June, as indicated by the contraction 

 (to the eastward) of the area inclosed by the surface isohaline for 32 per mille (cf. 

 fig. 120 with fig. 128). 



" Information kindly supplied by Dr. A. G. Huntsman. 



