Chapter II 

 INSTRUMENTS AND METHODS 



A report of some of tlie oceanographic apparatus of the Marion 

 Expedition 1928 is contained in the narrative of the cruise. (See 

 Ricketts and Trask, 1932. 



The subsurface temperatures were taken with deep-sea ther- 

 mometers belonging to the International Ice Patrol and manufac- 

 tured by Negretti & Zambra, Schmidt & Vossberg, and Richter & 

 Wiese. Most of the instruments were of the Negretti & Zambra make 

 with no auxiliary thermometer and graduated into two-tenths of a 

 degree centigrade. The remainder of the supply were fitted with 

 auxiliary thermometers, their main stems graduated in one-tenth of 

 a degree centigrade. There were a sufficient number of these latter 

 to pair with the former in each water bottle. Test certificates were 

 available for all thermometers, and readings were corrected to the 

 nearest one one-hundredth of a degree centigrade from prepared 

 correction graphs in the usual manner. 



The surface temperatures were taken with a dip bucket and a 

 thermometer of known calibration, graduated into tenths of a degree 

 centigrade. The corrected temperatures are so shown in the station 

 tables. 



As a result of the above-described methods, the record of tem- 

 peratures contained in the 1928 station tables are considered accurate 

 to within 0.03° C. An exception is to be noted, however, in the case 

 of station 1016, the only deep-water station taken north of the Davis 

 Strait Ridge. Proceeding downward at station 1016 the temperature 

 dropped to a minimum at 60 meters and then immediately rose to a 

 negative fraction which prevailed to bottom. Such a vertical distri- 

 bution of temperature does not agree with that at several nearby 

 stations taken by the Danish ship Godthaab (Conseil Permanent 

 International, 1929) prior and subsequent to the date of station 1016. 

 Nor do the Marion's temperatures agree with those of the typical 

 summer-time column in Baffin Bay which is characterized by a posi- 

 tive temperatured mid-depth layer. The constant increase of salinity 

 with depth at station 1016, on the other hand, precluded the most 

 probable interpretation, that the water bottles may have tripped be- 

 fore reaching the recorded depths. A comparison between the tem- 

 peratures at Marion station 1016 and Michael Sars station 46 and 

 Godthaab stations 162 and 163 has permitted corrections to be made 

 to some of those of station 1016, and, so qualified, they have been 

 allowed to enter the dynamic calculations. 



Water samples were stoppered in newly rubber-gasketed citrate 

 bottles and all salinities were determined by means of electric con- 

 ductivity. The two salinometers on board the Marion were con- 

 structed and calibrated at the United States Bureau of Standards, 



13 



