INTERN ATTONAIj ICE OBSERVATION AND ICE PATROL SERVICK. 85 



Temperature. — At the outer end of the section we find a surface 

 layer > 10° C. and 100 meters thick. This is so marked by high 

 salinity and temperature that we can unhesitatingly state it is Gulf 

 Stream drift. Chart "H" of surface temperatures m the vicinity of 

 the Grand Banks precisely agrees with Profile No. 2, showing a 

 rounded area of Gulf Stream water which had intruded westward to 

 47° 30' W. between 43° 30' N. and 44° 30' N. The current observa- 

 tions from astronomical positions at this point gave evidence of a 

 northeasterly set of 0.8 knot per hour. Note should be taken of the 

 8° C. and 6° C. isotherms whicli graphically illustrate the action of 

 heat loss by the Gulf Stream wnicn occurs concurrently with its 

 northern progress. Cold water normal for this latitude was found at 

 stations 167 to 170, to the westward of and on the bank. At station 

 175 a minimum of 1.5° C. was observed on the surface, warming to 

 4.1° C. at 750 meters. 



The striking feature of the profile is the absence of any evidence 

 indicating the presence of polar water where it is to be expected 

 during the greater part of the year. It is unfortunate that no station 

 was located nearer the slope of the bank, since station 175 may be 

 too far off to detect the presence of an attenuated tongue of Labrador 

 Current lying close to the slope. Examination of the surface tem- 

 perature chart "H," however, shows a narrow, tapering tongue of 

 30° F. (1.1° C.) water extending southward on the east slope to 

 43° 15' N., 49° 40' W. Tliis is sufficient to show that in all prob- 

 ability there was a weak and shallow attenuation of Labrador Current 

 next to the slope, which ceased completely at 43° 15' N., 49° 40' W. 

 It may be added that the navigator found no southerly set from 

 astronomical observations. 



PROFILE NO. 3. STATIONS 172, 173, 174. 



This section runs SSE. from the NE. extremity of the Grand Banks 

 over the slope into deep water. It was taken February 20-21. (See 

 chart "A.") Very stormy, cold weather was encountered, making 

 the oceanographic work hazardous and difficult. This line of stations 

 was especially sought in an endeavor to obtain a cut across the polar 

 current. 



Salinity. — Unlike the preceding profile, no sudden changes of water 

 are met. The saltest water lies at the outer end of the section; the 

 freshest water is over the bank. The bank station 172 is flooded by 

 water, which on the surface is 33.06 "/oo and at the bottom 33.27 °/oo. 

 This is Salter than characteristic bank water, but, on the other hand, 

 quite typical of water from the north, i. e., the Labrador Current. 



Temperature. — The warm surface layer (10° C.) is to be noted at 

 station 174. Station 173 at the surface had a negative temperature, 

 — 0.3° C, which fell to a minimum of —0.6° C. at 50 meters; then 

 rose to 4.9° C. at 750 meters depth. This is quite indicative of the 

 presence of polar water, although restricted to a surface layer only 

 50-75 meters in thickness. On the bank, polar water flooded station 

 172, causing negative temperatures from surface to bottom. 



We may here review conditions in the area at the time of the ice 

 observation cruise, February 8-26. The Labrador Current was found 

 setting diagonally across and around the northeast promontory of the 

 Grand Banks in a weak and shallow flow, the effect of which extended 



