i88i.] 
The Source of Electric Energy . 519 
sistance produces a reverse eleCtric current. But to under- 
stand the exa Ct relations between the molecules of the magnet 
and those of the coil a more definite acquaintance with the 
true character of magnetic motion would be requisite. It is, 
doubtless, a resistance to the magnetic rotation analogous to 
that which displays itself in the case of current induction, 
but one which cannot be properly comprehended without a 
clear idea of the character of the centripetal motions of 
molecules and atoms, and their mutual attractive relations. 
And as the production of harmonious relations between 
the molecules of a coil and of a magnet is accompanied by 
the formation of a momentary eleCtric current, so in the case 
of a substance rotating near the poles of a magnet there is 
a constant change of relations, since the rotation constantly 
brings new sets of molecules into propinquity to those of the 
magnet. There arises, therefore, a constant eleCtric current, 
made up of a continued series of temporary induced cur- 
rents. It is not the internal motions of the magnet, but the 
rotary motion of the other mass, which is here converted, 
first into electricity, but finally into heat. The magnet, in 
faCt, seems to exert an attractive resistance on the move- 
ment of the other body, which, under some circumstances, 
results in an immediate conversion of this movement into 
heat ; but where the substance is an unbroken eleCtric con- 
ductor, it yields first an eleCtric current, and finally heat. 
This eleCtric current shows that the magnet not only exerts 
an attractive resistance to the motion, but that it also pro- 
duces an eleCtric disturbance in the molecular energies. The 
result therefore is not increased heat-vibration, but eleCtric 
neutralisation, and the phenomenon of the eleCtric current. 
Electricity is principally concerned with the relations of 
solid and liquid surfaces. It produces little other effeCt upon 
gases than induction. Light and radiant heat are concerned 
with the relations of solids or liquids to gases, or perhaps 
only to that ultra-gaseous form called ether. Therefore, al- 
though the innate character of this mode of motion may be 
the same, its vibratory pitch may widely differ, and the con- 
ditions of the substance which it affeCts are so widely different 
from those of eleCtric substance that we cannot apply to 
these two series of phenomena the same methods of inves- 
tigation. The movements of static electricity are towards 
the surfaces of a conductor. When these surfaces are ac- 
cordantly electrified the energy ceases to be transmitted, and 
becomes truly static ; but if the conductor were infinite in 
extent it would take an infinite period to produce this surface 
accordance, and the eleCtric movement would continue inde* 
