PEIRCE. — MANNER OF GROWTH OP A CURRENT. 



515 



values of jx the current would decay very slowly. The actual values of 

 the ordinates of any curve would depend of course upon the number of 

 turns in the secondary, the resistance of its circuit, and the magnetic con- 

 stants of the solenoid. If for a fixed point in the core a curve be drawn, 

 by plotting q against t, for each of a number of different values of /j, the 

 ordinates of all these curves will have equal values at points where t/fi 

 has the same value. The maximum value of q, if it has one, is inde- 

 pendent of /A. 



At a point distant one tenth of the radius of the core from the axis 



Figure 5. 



Ho 



2 -k a 



* 'It? a .*■£* J x (n p a) 

 and ignoring algebraic signs, we have 



■AdV^q) H _ H S f 



27ra' 



(19) 



log 



log 



Jt iip a 



0.5141 

 0.5009 

 0.4473 

 0.3395 

 0.1378 

 9.6398 



