94 



point north of the Grand Banks. This was later verified to the extent 

 that Dr. Harold Thompson, director of the Newfoundland Fisheries 

 Research Laboratory, stated there was a greater abundance of arctic 

 forms of plankton along the Avalon Peninsula. The change in hydro- 

 dynamic conditions east of the Grand Banks came abruptly about the 

 beginning of May. 



In the current map for June, figure 21, the weaknes:? of the Labrador 

 Current in the northern part of the map is again noticeable, the posi- 

 tion of maxmium velocity having progressed southward to about lati- 

 tude 44°N. In spite of this, however, the current extends all the way 

 to the tail of the Grand Banks. The intrusion of Gulf Stream water, 

 although still present in about latitude 44° N., decreased in area from 

 what it was in May. This fact, combined with the previously men- 

 tioned existence of the Labrador Current all along the eastern edge of 

 the Grand Banks, meant that in 1935 the current situation was such 

 that the ice patrol could only be discontinued on the basis of scarcity 

 of ice, rather than on the basis of deflecting currents which would not 

 permit bergs to drift southward into the steamer lanes. 



In the following table of oceanographic data collected at stations 

 occupied in 1935 the corrected values of the actual observations of 

 temperature and salinity are given in addition to the scaled values. 

 The individual station headings give the station number, date, 

 geographical position, depth of water, and the dynamic height of the 

 sea surface above the reference surface used in the construction of 

 the dynamic topographic charts shown in figures 19, 20, 21, and 23. 

 For stations 1771 to 1937, inclusive, the sea surface is referred to the 

 1,000-decibar surface and the depth of water is the uncorrected sonic 

 sounding based on a sounding velocity of approximately 1,442 meters 

 per second. For stations 1938 to 2047, inclusive, the sea surface is 

 referred to the 1,500-decibar surface and the depth of water is the 

 sonic sounding corrected for draft and sounding velocity. It will be 

 noted that at station 2031 the depth of water is given as 1,940 meters 

 and the depth of the deepest observation is given at 2,000 meters. 

 This apparent discrepancy has been allowed to remain inasmuch as 

 the difference is considered to be about equal to the combined errors 

 in the sonic sounding and in the method of determining depths by 

 unprotected thermometers. Consideration was also given the fact 

 that the sonic sounding was not simultaneous with the reversal of 

 the deepest bottle. Where the depths of scaled values are enclosed 

 in parentheses, the data are based on extrapolated vertical distribu- 

 tion curves of temperature and salinity. Asterisks appearing before 

 observed temperatures indicate that these temperatures were deter- 

 mined from the depth of reversal and the corrected reading of an un- 

 protected thermometer. The symbol o-t signifies 1,000 (density — 1). 



