THE MEASUREMENT OF MAKE SHOCKS 95 
Z as applied to make shocks shall represent stimuli 
equal in intensity to those given by break shocks in 
which the value of Z is determined as above. The ex- 
perimental procedure by which the problem was solved 
was as follows: A series of equal make stimuli were 
obtained with the secondary coil at various distances 
from the primary. The " calibration number" for each 
secondary position was then multiplied by the intensity 
of primary current employed at that position, and the 
products for each experiment were set down in a table.* 
For the inner positions of the secondary coil, positions 
M 
which have relatively large values of - > the product 
Li 
X / was nearly constant; as the secondary coil was 
Li 
moved out into the parts of the field where the values 
of are small, the product X / became progressively 
Li L* 
larger the farther out the secondary coil was pushed, and 
M 
consequently the smaller were the values of Nu- 
LI 
merous repetitions of the experiment gave precisely sim- 
ilar results. 
These experiments indicated quite clearly the exist- 
ence of a comparatively simple relationship between 
make and break stimuli, and also suggested a method 
* For experimental data see Martin: Loc. tit., p. 272, 
