(NOIllSOd 



0Nld3M0"l NI) 



ENLARGED SECTION SHOW- 

 ING PIG-TAIL (A) APPENDIX 

 DEAD ARM (B) AND BREAK- 

 OFF POINT (C). 



■i®--- 



-®l 



ENLARGED SECTION SHOW- 

 ING READINGS ON MAIN 

 STEM (D) AND AUXILIARY 



- GLASS JACKET 



(IN REVERSED POSITION) 



UNPROTECTED 



Figure D-1. Protected and unprotected deep sea re- 

 versing thermometers. 



water temperature in sitxi. The temperature 

 scales of main protected reversing thermometers 

 range from -2° C. to as high as 32° C. 



D-6 Unprotected Reversing Thermome- 

 ters. — An unpi'otected reversing tliermometer 

 is similar to the protected except that the 

 heavy glass jacket that encloses the main and 

 auxiliary stems is open at one end, and it has no 

 meiTury surrounding the reservoir. Since the 

 unprotected thermometer is in direct contact 

 with the water and is subject to hydrostatic 

 pressure, it does not give a true temperature 

 reading; instead, it gives a reading which is in- 

 creased approximately 1° C. for each 100 meters 

 of depth. The unprotected thermometer, when 

 used with a protected thermometer, is a pres- 

 sure gage for determining the exact depth of 

 the thermometers at the time of reversal. The 



temperature scales of main unprotected revers- 

 ing thermometers range from -2° C. to as high 

 as 60° C. For extremely deep measurements 

 (ocean trenches), specially developed ther- 

 mometers with expanded scales to as high as 

 80° C. are used. 



D-7 Handling, Storing, and Transporting 

 Deep Sea Reversing Thermometers. — Deep 

 sea reversing thermometers are delicate pre- 

 cision instruments and must be handled with 

 care. Special carrying cases are used for storing 

 and transporting thermometers. Thermometers 

 always are hand carrie<l to and from tlie survey 

 ship. 



When handling a reversing thermometer, 

 never lay it on its side. The construction of 

 the thermometer is such that in a horizontal 

 position the mercury in the main thermometer 



D-2 



