116 



below the 450 meter (246 fathoms), at station 260. This suggests an 

 intrusion in the intermediate levels, just south of the Tail of the Bank, 

 by a body of Salter water whose source necessarily is the south. 

 (See discussion of profile No. 3.) The area to the northwest and 

 below the 300 meter (164 fathoms) plane was flooded by water salter 

 than 34*'/oo, which from its high salinity identifies this as Atlantic 

 water, on top of which the .\i-ctic water has spread in a gradually 

 thinning surface stream northwestward along the slope and away 

 from the Tail. 



Te)yiperature.—The predominance of water colder than 0° is the 

 most noteworthy feature of this profile. The salinity of less than 

 34''/oo and the temperature below 0° incloses a section of water 

 in the profile which is chiefly Arctic in origin. (See page 112.) 

 The correspondence between these two bounds attracts attention and, 

 like the salinity profile, it shows a gradually thinning volume of icy 

 water from the Tail to the northwest. At several levels at station 

 266, farthest to the northwest, was found the warmest water of 

 the section, which suggests that had the investigation been extended 

 a little farther we w^ould have run out of all Arctic water in a grad- 

 uall}^ thinning surface pool. 



PROFILE NO. 4— STATIONS 258, 266, 267, AND 268. 



The section runs from station 258, located in on the southwest slope 

 of the Bank, westerly into deep water. It was occupied April 14-17, 

 one of the objects being the location of the northwestern extension of 

 polar water, provided it had flowed to such a distance from the Tail. 



Salinity. — Fresh water < 33 "Uo salinity was found in on the Bank 

 from the surface to the bottom. The isohalines in the deep water 

 off the Bank assumed a more horizontal position than they do 

 farther southward around the Tail,, where normall}* the lines are 

 more vertical. The fact that there is no 34 %c water above the 250- 

 meter (137 fathoms) plane, even at the ofi'shore station, 268, would 

 lend support to the belief that the Gulf Stream la}^ a considerable 

 distance to the southward. 



Temperature. — Inshore on the Bank we foun<l no water as cold as 

 0°, hence consideration of both salinity and temperatures forbid the 

 presence of Ai'ctic water in over the Bank at this time and place. 

 (See p. 146.) The water colder then 0°, shown shadetl in the profile, 

 clearly reveals the presence and defines the bounds of a large quantity 

 of polar water, for water to be so coUi and so salt, 33.5 "/oo to 34 "/qq, 

 must have come from the Arctic. It was mostly restricted to the 

 upper 250 meters (137 fathoms), but it spread out for the unusually 

 great distance of 120 miles seaward from the edge of the Bank. 

 Since no polar water was found in on the Bank, it must havx been 

 ti'ansportctl to this locality, 120 miles west-iiorthwest of the Tail, 



