ELEMENTS OF ELECTRICAL ENGINEERING. 



(a) The part a is the original uniform field M. The lines of 

 force of this field are shown by the parallel straight lines in Fig. 8. 

 The amount of magnetic flux which passes out from the end of 

 the rod because of this uniform field M is Ms lines. 



Fig. 8. 



(b) The part b is the magnetic field due to the pole m of the rod. 

 The lines of force of this field are shown by the radiating straight 

 lines in Fig. 8. The amount of magnetic flux which passes out 

 from the end of the rod because of this field is ^inn lines, as 

 explained in Art. 7, Chapter I. 



The total magnetic flux 4> passing through the rod is equal to 

 the sum of the two parts, a and b, so that we have : 



(5) 



-f Ms 



or, since m 3s from equation (4), we have : 



Ms 



The part ^.irm or qrrds of the flux through an iron rod is 

 due to the magnetized condition of the rod, and the part Ms is 

 due to the magnetizing force directly. This part, Ms, is the 

 amount of flux which would pass through the region occupied by 

 the rod if the rod were removed. 



