Electrical Currents through Iron and Steel. 19 
electric currrent circulating through the helix B. When the 
circuit, therefore, was made through B and C, an induced eur- 
rent — through the helix A and the galvanometer, which 
was due to the magnetism of the core at the distance of 25 cm. 
from the face of the helix B. The iron core was then made a 
portion of an independent electrical current. Thus it was pos- 
sible to magnetize the iron core by the helix B, and to send a 
current through it in the axial direction by the independent 
circuit. We shall call the magnetizing circuit circuit a, and 
the axial circuit circuit f. | 
The circuit a was first made and the deflection of the gal- 
vanometer noted; it was then broken. The following table 
shows the results obtained: 6, represents the deflection pro- 
duced by the magnetism of the bar, 6’, after the circuit # was 
made, 6’, after the breaking of the circuit 6. Two Grove cells 
were used upon the circuit f. 
TABLE I, 
é 0” é”” 
110 150 155 
110 145 150 
110 150 155 
110 150 155 
This table shows that the instantaneous passage of the axial 
current through the iron bar gave rise to an increase in its 
magnetism. This phenomenon was apparent both at making 
d ng the axial circuit. e Increase of magnetism 
rent # was sufficient to produce the increase of magnetism. 
The following table shows the effects produced by allowing 
