APPENDIX A 



A-l NOTES ON MALFUNCTIONAL BE- 

 HAVIOR AND ITS CORRECTION IN DEEP- 

 SEA REVERSING THERMOMETERS.— The 



following notes on malfuiictional behavior and 

 its correction in deep-sea reversing thermom- 

 eters (Whitney, 1952) are given here in the 

 entirety. 



A-2 Introduction. — In the course of work- 

 ing with and calibrating some 400 deep-sea 

 reversing thermometers of various types and 

 manufacture during the past year or so, oppor- 

 tunity has been afforded to study the different 

 types of malfunctions occurring in reversing 

 thermometers, and to investigate various correc- 

 tive measures to restore proper functioning. 

 It is thought that the results of this investi- 

 gation may be of interest and assistance to 

 oceanographic personnel who have occasion to 

 work with these instruments. 



Malfunctions, which may be described as 

 failure of the mercury column of the main 

 thermometer to break correctly at reversal, 

 are a source of annoyance to observers. When 

 the mercury thread breaks very near but not at 

 the correct breaking point, a false reading 

 occurs which is not readily detectable as such, 

 and may result in false information being 

 entered on the station data sheets. 



A-3 Types of Malfunctions. — There may be 

 considered to be four basic types of malfunc- 

 tions, as follows: 



1. The mercury breaks either on the stem or 

 reservoir side of the appendix or constriction; 

 if on the reservoir side or in the throat of the 

 reservoir, the mercury runs out of the appendix 

 or entirely clears the constriction. 



2. The mercury breaks on the reservoir side 

 of the appendix or constriction or in the throat 

 of the reservoir; some mercury remains (sticks) 

 in the appendix or in the constriction. 



3. The mercury column does not break at 

 all at reversal, but runs down filling the entire 

 capillary system, leaving a visible bubble in 

 the reservoii-. 



4. The mercury column neither moves nor 

 breaks at reversal unless or until the instrument 

 is jarred, sometimes quite solidly, which jarring 

 will usually cause the instrument to function 

 incorrectly in 1 of the 3 ways described above. 



H. O. 607 



A-4 Definitions. — To insure clarity, the 

 terms which will be used in this discussion are 

 here defined. 



Reservoir: The usually cylindroid glass por- 

 tion of the thermometer which holds the prin- 

 cipal body of mercury. The reservoir is at 

 the bottom when the instrument is in its 

 upright position. 



Bulb: The small expansion chamber at the 

 opposite end of the thermometer from the 

 reservoir, which is at the top when the instru- 

 ment is in its upright position. 



Upright: That vertical position of the instru- 

 ment in which the zero point of the main ther- 

 mometer is near the top of the instrument. To 

 right is to move the instrument to the upright 

 position. 



Reversed: That vertical position of the instru- 

 ment in which the zero point of the main 

 thermometer is near the bottom of the instru- 

 ment. (The thermometer is always read in the 

 reversed position.) To reverse is to move the 

 instrument to the reversed position. 



Appendix: The small branch, or dead-arm, 

 off the main capillary channel near the reservoir. 

 The mercury is supposed to break on reversal 

 at the junction of the appendix with the capillary. 



Constriction (sometimes referred to as the 

 collar button from its general appearance) : A 

 type of breakoff point made by pinching the 

 capillary together while plastic to deform it 

 and reduce its nominal diameter. In this 

 discussion, unless reference to this particular 

 type of construction is specifically intended, 

 the word appendix will be broadly used in 

 connection with either type of breakoff point. 



Pigtail: The 360° turn, or equivalent thereof, 

 as an S shape, between the appendix and stem 

 which acts as a trap for any mercury extruding 

 from beyond the appendix as the result of a 

 temperature rise after reversal. 



Capillary: The bore of the thermometer from 

 reservoir to bulb, in which the mercury moves. 



Stem: The straight, graduated section of the 

 thermometer. 



Throat of the bulb: The point at which the 

 straight capillary diameter of the stem begins 

 to open out to form the bulb. 



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