PEIRCE. — ESTABLISHMENT OF CURRENT IN COIL. 



163 



unit, and 100 ampere-turns as the horizontal unit. In consideration 

 of the units here chosen the growth of the excitation in the core (in 

 ampere-turns) would be given by the equation 



JfTi 

 U(T)dT 

 o 



(12) 



Therefore, it is clear that the area, between the limits of T = and 

 T = jTi, divided by 20 gives the time in seconds for the excitation to 

 grow from to TV The third column of the table contains a number 



Figure 8. Magnetization curve for the finely divided core of the trans- 

 former (DN) which at the outset is in a neutral state. The dotted curve 

 represents, on an arbitrary scale the slopes of the other. 



