102 INDUCTION SHOCKS 
For Z m the expression is 
M M 
L L__ ^ 
2000 + |f ~~ 2001.8 
The difference between the stimulating intensities of the 
two sects of shocks is in this case less than one-tenth of 
one per cent. Compare now the values of Z& and Z m when 
a primary current of 0.4 ampere at 2 volts is used. The 
expression for Z b is M_ 
L_ 
2-5' 
and for Z m is 
M M 
L L 
2.5+ 5 2 6 - 20.5 
In this case the break shock is more than eight times as 
intense as the make. 
The above illustrations present in concrete form the 
effects upon the relation between break and make stim- 
uli of variations in intensity and voltage of the primary 
current. These effects may be stated in general thus: 
The higher the voltage of the primary current and the less 
its intensity, the more nearly will make shocks equal break 
shocks: conversely, the lower the voltage of the primary 
current and the greater its intensity, the more will break 
shocks exceed make shocks. 
