INDUCTION SHOCKS 
TABLE II 
Effect of the Iron Core on the Rate of Change of Stimulation 
Intensity in the " Critical Region " of the Inductorium 
Iron core absent. 
Iron core present. 
Position of sec- 
ondary in cen- 
timeters. 
Kronecker 
graduation. 
Percentage de- 
crease per centi- 
meter. 
Author's cali- 
bration. 
Percentage de- 
crease per centi- 
meter. 
8 
6190 
6240 
9 
5150 
17.0 
5340 
14.4 
10 
4I5 
19.4 
4500 
15-7 
ii 
3250 
21.7 
3600 
20 
12 
2375 
27.0 
2640 
26. 7 
13 
1570 
33-9 
1920 
27-3 
14 
IOOO 
36.3 
1270 
33-8 
15 
625 
37-5 
860 
32.1- 
16 
435 
30-4 
600 
30.3 
17 
310 
28.7 
455 
24.2 
18 
230 
25-7 
35 
23.1 
iQ 
178 
22.7 
280 
20.0 
Table II gives a comparison of the calibrations in the 
" critical region" of one inductorium made without and 
with the iron core. The primary coil of this instrument 
was 14 cm. long. The table shows clearly that the rate 
of decrease of stimulation intensity from point to point 
is greater when the iron core is absent than when it 
is present. Table III is the record of experimental 
verification of the same fact. Stimulation intensities 
were compared in these experiments according to the 
v. Fleischl method (p. 56), namely by comparing the 
primary currents required to produce stimuli of equal 
value with the secondary coil at different positions. 
