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HANDBOOK OF MAGNETIC COMPASS 



29. The nature, magnitude, and polarity of all these induced effects 

 are dependrait upon the disposition of metal, the symmetry or assym- 

 metry of the ship, the location of the binnacle, the strength of the 

 earth's magnetic field, and the angle of dip. 



30. Certain heeling errors^ in addition to those resulting from per- 

 manent magnetism, are created by the presence of both horizontal 

 and 'vertical soft iron which experience changing induction as the 



North heading by Northeast heading East heading by Southeast heading 

 • compass. by compass. compass. by compass. 



Compass 



-W. Dev. 



Compass 

 Needle 



Hods of 

 Soft Iron 



Maximum devia- 

 tion easterly. 



E 

 (r) 



Deg, 

 Dev. 



W 

 (-) 



No deviation. 



"E" Deviations 



ilaximum devia- 

 tion westerly. 



No deviation. 



N NE 



Compass Heading - Degrees 

 Figure 17. — Effects of unsymmetrical horizontal E induced magnetism. 



ship rolls in the earth's magnetic field. This part of the heeling 

 error will naturally change in magnitude with changes of magnetic 

 latitude of the ship. Oscillation effects accompanying roll are maxi- 

 mum on north and south headings, just as with the permanent mag- 

 netic heeling errors. 



31. Adjustments and correctors. — Since some magnetic effects 

 remain constant for all magnetic latitudes and others vary with 

 changes of magnetic latitude, each individual effect should be cor- 



