The oceanographic work was under the supervision of Oceanog- 

 rapher Floyd M. Soule United States Coast Guard who was assisted 

 by Lt. Robertson P. Dinsmore, U. S. C. G., Lt. Rudolph E. Lenczyk, 

 U. S. C. G. and Lt. Jay H. Bramson, U. S. C. G. Other assistants 

 in the observational work were Francis N. Brown, yeoman second 

 class; Lewis M. Lawday, aerographer's mate, second class; Donald 

 M. McGill, aerographer's mate, third class; Hugh R. McCartney Jr., 

 aerographer's mate, third class; and Joseph R. Stefanick, seaman, 

 all United States Coast Guard. 



Of the 381 stations occupied during the season and postseason 

 cruises, the 24 stations comprising the section across the Labrador 

 Sea we're occupied from the surface to as near bottom as was prac- 

 ticable, and at the remaining 357 stations the observations extended 

 to a depth of about 1,500 meters where the depth of water permitted. 

 As in previous years the intended depths of observation, in meters, 

 were 0, 25, 50, 75, 100, 150, 200, 300, 400, 600, 800, 1,000, and thence 

 by 500-meter intervals. For the first survey, the dynamic topography 

 oi" the southern shallower part has been referred to the 1000-decibar 

 surface and the northern deeper part has been referred to the 1500- 

 decibar surface. The results have been presented in two charts havuig 

 sufficient overlap to provide continuity in their interpretation. The 

 1,500-decibar surface has been used for reference in the section across 

 tiie Labrador Sea. For all other stations the dynamic heights have 

 been referred to the 1,000-decibar surface. 



In addition to the usual measurements of temperature and salinity, 

 696 samples during the second cruise, and 288 samples during the 

 postseason cruise, were taken for ultimate determination of total 

 phosphorus concentration. 



Temperatures were measured with deep sea reversing thermometers. 

 Most of the protected thermometers were of Richter and Wiese man- 

 facture but a small percentage were manufactured by Negretti and 

 Zambra, G. M. Manufacturing Co., and the Kahl Scientific Instru- 

 ment Corp. The depths of observation were based on Richter and 

 Wiese unprotected thermometers. The thermometers were used m 

 pairs. The thermometers were shifted periodically so that a ther- 

 mometer eventually was paired with several other thermometers thus 

 providing rather extensive intercomparison. This program permitted 

 recognition of those thermometers which were not functioning properly 

 and also permitted a determination of consistent errors in the scale 

 correction in use. The series of intercomparisons provided means of 

 estimating the precision of the temperature measurements. Consider- 

 ing 2 458 comparisons the probable difference between the corrected 

 readings of a pair of thermometers was ±0.012° C. As many of the 

 thermometers had recent laboratory comparisons with thermometers 

 tested by the National Bureau of Standards, and as m most cases 

 the temperatures are the means of the corrected readings of a pair ot 



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