waters of high thermal gradients. Certain recent anchor stations indicate a need 

 to investigate the rate of response further. Incorporation of rate of response into 

 the testing procedures seems advisable as part of the procedure of checking all 

 phases of operation of the Bathythermograph. 



6.1.8. Reproducibility Tests 



The simple procedure of running a Bathythermograph through tvi^o simul- 

 taneous cycles would give adequate determination of the ability of the Bathy- 

 thermograph to reproduce results, and an indication of its stability. It is a fairly 

 well established fact that when a Bathythermograph is repaired, especially when a 

 bellows is replaced, the first flexing under water pressure it receives produces an 

 initial fatigue set. It is almost mandatory that a new or freshly repaired instrument 

 be flexed to overcome this initial fatigue set. 



6.1.9. Smoothness Tests 



Major and minor wiggles have long been observed in the traces of operated 

 Bathythermographs. There is much debate as to whether these wiggles are pres- 

 ent in the ocean or the instrument. 



The same tests that would be conducted for hysteresis would also show the 

 smoothness of response, and would resolve the origin of the wiggles as to in- 

 strument or ocean. Operationally, the smoothness test would show if the instru- 

 ment had any inclination to hang or catch along its temperature depth route. This 

 is especially important in the very top layers, where small amounts of friction and 

 inertia will prevent the instrument from responding. 



6.1.10. Standardization of Testing Procedure 



It appears well in order that the whole picture of calibration be thoroughly 

 studied with a view to recommending the best and most desired testing proce- 

 dures. Adoption of such recommendations would serve to standardize the entire 

 testing program, giving more uniform and more reliable results. 



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