thermometers. (Experiments have shown this time to be 

 adequate. ) Then the vessel is reversed, the pressure is 

 released, and the rack removed from the vessel and placed 

 on a pivot behind the tank window. Here the thermometers 

 are read through the telescope while still immersed in 0°C 

 water. This procedure is followed twice at each pressure, 

 and the tests are continued, increasing the pressure by- 

 increments of 100 kg/ cm' to the limit of the thermometer 

 scales. The Q factor is determined from the readings and 

 the data noted on the individual calibration sheets. 



DISTRIBUTION 



All original calibration sheets are kept at this 

 Center to form histories of each thermometer. A Xerox 

 copy of the most recent calibration data sheet is issued 

 with each instrument. 



THERMOMETER CARE 



Thermometers are stored in a special reversing 

 rack which holds 210 thermometers in a vertical position 

 (fig. 11), They are reversed weekly to keep the mercury 

 flowing freely through the capillary. Seventy thermometers 

 can be tripped simultaneously. 



CALIBRATION OF OTHER SENSORS 



The NUWC Temperature Calibration Facility is 

 being increasingly used to calibrate oceanographic devices 

 other than deep-sea reversing thermometers, for example, 

 thermistor beads. Forty-eight of these heat-sensing probes 

 are spread along the NUWC Thermistor Chain, which is 

 suspended from the fantail of the oceanographic research 

 vessel USS MARYSVILLE and used in the study of the 

 temperature structure of the oceans. In addition, numerous 

 vertical and horizontal arrays of temperature sensors are 



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