94 IXTERNATIONAL ICE OBSERVATION AND ICE PATROL SERVICE. 



though it can not be denied thnt future experience may call for 

 modification. 



The ice-observation vessel on its February cruise succeeded in 

 locatin*!^ and charting the surface and subsurface shape of the 

 Labrador Current in tne vicinity of the Great Bank. We definitely 

 ascertained that this current did not extend south of the Tail of 

 the Bank during February; though at that time it completely 

 flooded the northern and northeastern parts of the bank, and pro- 

 jected out over the slope to the eastward for 40 miles. The Labrador 

 Current was thickest on the rounded northeast promontory of the bank 

 where it extended down the slope 170 meters (93 fathoms). Thence, 

 southward its esistern and western walls quickly converged, fonning 

 a narrow fingerlike extension over the 200-fathom contour, reaching 

 southward only to 43° 15' N., 49° 40' W. 



Much to our surprise upon the return of the ice-observation vessel 

 to the Great Bank the middle of March, icebergs were discovered 

 aroimd the Tail. A line of stations run from the Tail to the south- 

 east gave the explanation by showing that during the interval between 

 the two i-ruises, i. e. P'ebruary 25 and March 17, a great augmentation 

 of the Labrador Current had taken place, extending south along the 

 slope from its earlier limit, 43° 15' N., as far as the Tail of the Bank. 

 It was this propulsion of water out of the north which bore the first 

 icebergs down to the Tail. 



Two weeks later this northern cm rent had increased to such 

 proportions that it extended on the suiiace 30 miles south of the Tail 

 and to a maximum depth of 500 meters (255 fathoms) down the 

 slope. Its most striking feature was that it was no longer confined 

 on the west by the slope, but had spread inward over the bank, 

 displacing the bank water. By this process it had not oTily pushed 

 diagonally across the Tail of the Bank, but it had also sunk down the 

 slope to a de])th of 400 meters. The trunk of the current, like other 

 ocean currents, seeks the steepest part of the slope, the excess ac- 

 cumulation of water crowding in over the bank, and curving in a 

 southwest and west flow. Its efl'ect was apparent ft)r 30 miles 

 out over the southwest slope of the bank as far west as 43° 00' N., 

 51° 00' W., beyond which there was no trace of it. 



From the middle of April on to the end of the patrol, when obser- 

 vations were necessarily disc(mtinued, the Labrador Current was 

 constantly present in the vicinity of the Grand Banks of Newfound- 

 land; though during this period it was subject to many variations in 

 position, form, and strength. By the first part of May the current 

 exhibited a tendency to spread to the southw ard in a shallow sui-face 

 layer around the Tail of the Bank, extending then 70 miles south of 

 the slope and ou the average SO meters (44 fathoms) Ihick. By the 

 last of May there was a weakening of the Labrador (\nTent west of 

 \]\v 'i'ail. On the southwest slope where it had Mowed so strongly in 

 April, it was now no longer apparent. The polar water previously 

 found there had been warmed up beyond recognition by mixture with 

 the local water of higher temperatm-e. liy June the Labrador 

 Current was confined to the slope and to the bank, a state of affairs 

 f|uite similar to that which existed the first part of April, there being 

 in June no Arctic water on the southwest slope. The fact tliat there 

 was no Arctic, water over the southwest slope in June, argues for an 

 actual recession to the eastward. 



