Mr. T. H. Blakesley on Magnetic Lag. 39 



A 



Substituting the electric quantities for the geometrical, 



— ??iL cos BAF =??ili — 5 — nlc, cos 6 + in 2 !* ; 

 r± n z r x 



multiply through by ^ 



EIj cos BAF _ m IJ* cos fl rj^ 



2 V - 5 + TT 



But the term on the left is the expression for the total power, 

 and those on the right hand may be expressed in terms of 

 the dynamometer observations. 

 Thus the total power 



= r 1 Aa 1 + r 2 — ta 3 . 

 n 



The first term here is obviously the power at work heating 

 the primary coil. 



?* 2 B« 2 is as obviously the power heating the secondary coil. 



If, therefore, we write the total power 



= r 1 Au l + ?' 2 Ba 2 + r 2 i ™ Ca 3 — Ba 2 j- , 

 we see that the power involved with the magnetic lag is 



-i{=ck-m}, 



the form showing that it disappears if the lag does so. 



Thus we are led to the conclusion that a magnetic lag 

 involves a loss of power, and any loss of power due to mole- 

 cular action in the core taking place in the course of the 

 alternations of magnetization must necessarily produce lag. 



Now if the changing magnetization does work it must do 

 it against a force, and this force must be of the character 

 which of itself would produce magnetization, i. e. magnetic 



