104 HANDBOOK OF MAGNETIC COMPASS 



by securing each of the degaussing coils by a reversal and daTnping 

 process as follows : 



TO SECUKE COILS 



(1) Start with maximum DG current used since the DG coil 

 was last secured. Reduce the current to zero and energize to same 

 value in the reverse direction. 



(2) Reduce the current to zero and energize to three-fourths 

 value in original direction. 



(3) Reduce the current to zero and energize to one-half value 

 in reverse direction. 



(4) Reduce the current to zero and energize to one-fourth value 

 in original direction. 



(5) Reduce the current to zero and then energize to one-eighth 

 value in reverse direction. 



(6) Reduce the current to zero and open switch. 



To eliminate possible residual, this procedure should be employed 

 every time a degaussing coil is secured, if necessary. This procedure 

 may not always be possible, as with some switch-type installations. 



