114 



classified as belonging to the Gulf Stream. Its northern face pre- 

 sented a nearly vertical temperature boundary, a phenomenon which 

 is characteristic of late winter and early spring when convectional 

 circulation has attained its maximum influence, and a state which is 

 strikingly illustrated by vertical profile No. 3. At the time this sec- 

 tion was made, the '''cold wall" was approximately 90 miles south of 

 the Grand Bank, which is 10 miles farther from the slope than west 

 of the Tail. (See profile No. 2.) Water colder than 0° lay on the 

 slope and downwards to a depth of 650 meters (350 fathoms) . Its Urn 

 temperature of - 1.5° and its high saUnity of 34° /oo, further substan- 

 tiated by a minimum temperature below the surface followed by a 

 successive rise, identifies this water as Labrador Current which was 

 washing the Tail of the Bank at this time both down the slope and in 

 over the bottom. 



A comparison with profile No. 2, taken normal to the continental 

 edge two days earlier and at a point 30 miles to the westward of the 

 Tail, portrays a greater range and degree of contrast of isohalines and 

 isotherms than that noted in profile No. 3. Such a condition signifies 

 intense activity of the water masses and permits us to state that at 

 this time there was much more circulatory activity on the southwest 

 slope of the Bank than at the Tail. Further comparison discloses a 

 greater volume of Arctic water to the westward than at the Tail and, 

 since it is well established that the direction of flow is from the Tail 

 to the westward (see Treasury Bull. No. 10), we are justified in con- 

 cluding that a maximum flow of Arctic water occurred at a date prior 

 to April 14-15, and when this investigation was made there had b('(>n 

 a slacking in the current from the north around the Tail. This is 

 an example of the irregular variations manifested by the southern 

 extensions of the I>abrador Current in the vicinity of the Tail of the 

 Grand Bank. 



PROFILE NO. 3a. STATIONS 257. 260, 265, AND 266. 



This section runs parallel to the southwest slope of the Grand Bank 

 and at a distance of 10 miles out from the continental edge, where the 

 maximum volume of polar water is usually situated. The section was 

 occupied April 14-16 and gives a picture of the extreme extension, in 

 longitudinal section, of the Labrador Current, in this direction, after 

 it has curled around the Tail and flowed to the northwest along the 

 southwest slope of the Grand Bank. 



SaUnity. -'W titer 33.28''/„o to 33.5"/o„ lay on the surface as a mere 

 surface film, 20 meters (11 fathoms) thick at the Tail, but increasing 

 to 135 metei-s (74 fathoms) at the station farthest to the northwest. 

 266. All deptlis below the 300 meter (164 fathoms) plane are flooded 

 by 347oo water, except around the Tivil, where the 34"/„„ water has 

 overridden the fresher 33.5"/„o water, which is to be seen at all depths 



