Magnet on Electric Currents. 201 
a fluid it will move in obedience to this force, and this motion 
may or may not be accompanied with a change of position of 
the electric current which it carries. But if the current itself 
be free to choose any path through a fixed solid conductor or a 
network of wires, then, when a constant magnetic force is made 
to act on the system, the path of the current through the con- 
ductors is not permanently altered, but after certain transient 
phenomena, called induction currents, have subsided, the dis- 
tribution of the current will be found to be the same as if no 
magnetic force were in action. The only force which acts on 
electric currents is electromotive force, which must be distin- 
guished from the mechanical force, which is the subject of this 
chapter.” 
This statement seemed to me to be contrary to the most natu- 
ral supposition in the case considered, taking into account the 
fact that a wire not bearing a current is in general not affected 
Y 4 magnet and that a wire bearing a current is affected ex- 
actly in proportion to the strength of the current, while the size 
and, in general, the material of the wire are matters of indiffer- 
ence. Moreover in explaining the phenomena of statical elec- 
tricity it is customary to say that charged bodies are attracted 
toward each other or the contrary solely by the attraction or re- 
pulsion of the charges for each other. 
Soon after reading the above statement in Maxwell I read an 
article by Prof. Edlund, entitled “ Unipolar Induction ” i 
Mag., Jet., 1878, or Annales de Chemie et de Physique, Jan., 
1879), in which the author evidently assumes that a magnet acts 
—_ 
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of the =e and therefore the resistance experienced should be 
ease . 
