in the Chukchi Sea represent a considerable increase in the 

 oceanographic information available concerning this area. 



Also shown on figure 13 is the location of the line of 

 bathythermograms obtained in the run from Adak north to the 

 southern edge of the extensive shallow water area of the Bering 

 Sea. It was in this shallow water region, north from the area 

 of the Pribilof Islands, that all the hydrographic stations in 

 the Bering Sea were obtained. At each hydrographic station 

 vertical water temperatures were obtained from both bathy- 

 thermograms and reversing thermometers. The bathythermo- 

 graph observations are extremely valuable from the standpoint 

 of description of the thermal structure, since a continuous 

 temperature trace with depth is obtained. Because of this 

 greater detail given by the bathythermograph observations, 

 all vertical cross sections are based on bathythermograms 

 and the isotherms are in degrees F. 



The accuracy of the temperatures from bathythermograms 

 varies with the calibration and construction of the instrument. 

 Instruments which have developed a temperature set are 

 compensated for, in printing of bathythermograms, by adjusting 

 all temperatures by the amount of the average set, based on 

 the average difference between the surface trace and the 

 surface bucket temperatures. The accuracy of temperatures 

 from bathythermograms is thought to be within O.Z to 0.3 de- 

 gree F by compensating for sets. The bathythermograph 

 depth recordings, aside from adjustments in setting the top 

 of the trace on the zero depth line, were not calibrated while 

 in use. All depths are based on the previous calibrations of 

 the individual instruments. 



Temperatures taken by means of reversing thermometers 

 were more accurate than those taken by means of bathythermo- 

 graphs. Both German- and American-made thermometers 

 were used. Because of the low temperature water encoun- 

 tered, the thermometers were allowed in all cases to come 

 to equilibrium for 15 minutes before tripping. By comparing 

 duplicate readings and from previous experience with similar 

 thermometers, it is believed that the accuracy of the German 

 thermometers is within 0.02 degree C and that the accuracy 

 of the American thermometers is within 0.05 degree C. When- 

 ever readings were taken using only American thermometers, 

 these readings are noted in the tabulation of temperature data 

 with an asterisk. The greater accuracy of the temperatures 

 obtained by the use of reversing thermometers simultaneously 

 with the taking of water samples is needed for computations 

 of density and dynamic topography. 



