516 The Source of Electric Energy. [September, 
exist, and every molecule is tied to every adjacent molecule 
by close ties of affinity. The tendency to produce conformity 
of molecular condition, to which we have ascribed the pro- 
duction of eleCtric phenomena, goes further, and yields a 
resistance to every change in the motive conditions of one 
substance which is calculated to destroy its harmony with 
the motive conditions of adjacent substances. To this prin- 
ciple are probably due certain other effects, which are known 
as current induction and magnetic induction. Suppose, for 
instance, that two aggregates of molecules have produced 
their full effeCt upon each other, in accordance with their 
relations of position and constitution, and that now some 
new and special motive condition be given to the molecules 
of one of the masses. What will result ? Their relations 
of condition will evidently be changed, and a new conformity 
must be established between them. Yet it seems equally 
evident that a resistance to this change in condition will be 
exerted, the two sets of molecules striving to preserve their 
former relations. There is a principle of inertia here dis- 
played, and the new motion added to the one is partly 
prevented by, and in the same degree imposed upon, the 
other. There is a general principle of resistance to such 
changes, such as the movement of one body while the other 
continues at rest, or a new movement of the molecules of 
one while those of the other are undisturbed. And this 
principle of resistance produces very marked results. 
If, for instance, two wires be placed in close relations of 
contiguity, an influence is at once exerted by each upon the 
other, and a certain conformity of condition established be- 
tween their molecules. But if, now, one be made the con- 
ductor of an eleCtric current, every phase of the establishment 
of this current will be resisted by the molecules of the second 
wire, and the molecules of this second wire will be forced 
into new relations of conformity with the changed conditions 
of the first. The establishment of the current is preceded 
by an induCtive aCtion. This is resisted by the second, and 
produces an opposite induction upon the second. The posi- 
tive and negative polar conditions in the first are met by 
negative and positive polar conditions in the second. This 
condition in the first is followed by the current flow of posi- 
tive force in one direction and of negative in the other. But 
this, too, is resisted. The positive poles of the molecules of 
the first are attractively related to the negative poles of the 
molecules of the second. When these positive poles of the 
first move forward they are retarded in their movement by 
the negative poles of the second, and drag these forward to 
