184 Trowbridge and Adams — Circular Magnetization, etc. 



It might be supposed that we could have made a known 

 change in the current by employing one-half the battery to 

 charge the condenser. One-half, however, was not sufficient 

 to charge the condenser to such a degree that sufficient light 

 could be obtained in the spark. We believe that the following 

 inference, however, is correct : the permeability is seen to 

 increase with increasing field strength, in spite of the increase 

 of frequency. But the increase, of permeability with increase 

 of field strength is seen to be much less rapid than in the case 

 of steady currents. For, from the table of Klemencic, a per- 

 meability of 327 corresponds to a maximum current of about 

 0*8 amperes, while a permeability of 711 corresponds to a cur- 

 rent of about 14 amperes. But in the case of an oscillatory 

 discharge, these two values of the permeability correspond to 

 maximum currents of 140 and 742 amperes respectively. This 

 clearly shows the effect of period in diminishing the perme- 

 ability ; for the same change of permeability is produced by 

 increasing the currents in the ratio 8 : 14 with steady currents 

 as is produced by increasing the currents in the ratio 1 : 5 in 

 the case of oscillatory currents. 

 Jefferson Physical Laboratory, Harvard University. 



