INTERNATIONAL ICE OBSERVATION AND ICE PATROL SERVICE. 95 



Tlie eastern boundary of the current from the north is yet to be 

 (iiscussed. There appears to be more mixino: and interdigitation of 

 pohir and Athmtic water to the eastward of the Great Bank than in 

 any other area. Consequently, the boundary between the two 

 waters is one which is very difficult to determine. The Labrador 

 Current impinges itself at the Tail of the Bank on the northern edge 

 of the Gulf Stream. At times the push is strong enough to split the 

 Labrador Current into an east and west branch; in this case the 

 stronger branch determines the berg drift, the relative strength of the 

 branches probably depending to a great extent on the angle of im- 

 pingement of the Labrador Current against the Gulf Stream. An 

 illustration of this appears on berg chart "E," showing two bergs, 

 ''F" and ''G," both of which took the east branch, which was 

 evidently the dominating factor at that time. 



The conflict of the two currents, together with the position of the 

 bank produces a frictional arresting of the Gulf Stream on its northern 

 edge, which in turn swings it in sharply to the north and northwest 

 immediately after passing the Tail. This inshore westward swirl of 

 frictional bands of the Gulf Stream sets up an interlacing movement 

 between the two waters. The surface temperature charts "H" to 

 '•P" show the curling, eddylike character of the western boundary 

 of the Gulf Stream east of the Great Bank and indicate the general 

 form. But they can not depict the more detailed projections and 

 eddies that must be a constant accompaniment of the active inter- 

 digitation. Profiles Nos. 8 and 12 indicate the subsurface mixing. 



L^nlike the eastern area, the body of water between the Great Bank 

 and the Nova Scotia Bank is comparatively free from disturbing 

 mixings, except just west of the Tail, where the western extension of 

 the Labrador Current is active at times, and also farther south, where 

 heads of Gulf Stream water protrude in undulating form north of the 

 43° parallel. Their shapes and positions are variable, but they extend 

 farthest north during summer and autumn, when warm tropical 

 water is found close to the Nova Scotia and Newfoundland slopes. 



The polar water and Atlantic water as represented by the Labrador 

 Current and the Gulf Stream, respectively, have been discussed. 

 There is a third kind of water present which it is necessary to consider, 

 namely, bank water. The Great Bank extends 250 miles south- 

 southeasterly from Newfoundland. It is the largest bank promontory 

 in the world. Like other banks, it is normally covered by a mass of 

 water which, from its low salinity is known as bank water. This 

 water possesses characteristics which are definite and striking. 



The profiles for 1922 show that the bank water is subject to great 

 ranges in temperature. In winter the cold northwest winds from 

 Canada chill it to 0.0° C. from surface to bottom, while in August, 

 under the influence of southwest winds and solar warming, its tem- 

 perature rises to 12° "14° C. Contrasted with this is the annual 

 rang^e of the Gulf Stream in the locality, which is not greater than 

 6° C. — less than one-half that of the bank water. The latter is 

 subject to fluctuations in temperature caused by seasonal changes or 

 by water admixtures. 



The characterizing feature of this water is the persistence of its 

 low salinity, which even the salter water from the north, east, or 

 south does not appreciably alter, except near the slopes. It is true 

 that the Labrador Current floods the northern part of the bank most 



