39 ° 
The Source of Electric Energy . [July, 
neutral, and all the charge is confined to the surface. The 
portion of the charge on any one surface by its induCtive 
action tends to disturb the energies of all interior molecules, 
and to produce an induced charge upon the opposite surface. 
But the portion of the charge on this surface exerts an equal 
influence in the opposite dire(5tion. Thus the internal mole- 
cules, not being able to respond simultaneously to two 
exactly opposite and equal influences, remain unaffected, 
and all the eledtric charge is confined to the surface. The 
force which confines it there is not really a mutual repulsion 
of the surface charge, but pradtically it produces the effeCt 
of such a repulsion. 
The case of the approach of two similarly charged con- 
ductors is essentially the same as the above. If brought 
into contaCt they aCt precisely like a single body, opposed 
induCtive energies affedt the molecules in contadt, and their 
charge is transferred to the remaining surfaces. But, as 
there is in this case a decrease in the extent of available 
surface, the vigour of charge on each portion of the surface 
is increased. Possibly the abnormal vibrations swing 
through a wider space in consequence of this crowding of 
their energy into a more contracted region. If the charged 
conductors be slightly separated, the effeCt is simply to 
introduce an element of resistance into the problem. The 
induCtive effedts on the adjacent surface of each of xhe bodies 
differ in degree, since in the one diredtion it is induction 
through the conductor only, in the other it adts through the 
condudtor and the dieledtric medium. This difference in 
induCtive vigour results in a return of a portion of the 
charge to these adjacent surfaces, and this increases rapidly 
as the bodies are further separated and the dielectric 
resistance increased. No matter how closely two such 
bodies may be brought together, there is still a slight resist- 
ance, and thus a remnant of charge. And even in the 
interior of the best conductor a slight resistance exists. 
Therefore the induCtive effedts cannot be exadtly balanced, 
even within the interior of a good condudtor, except at its 
central portion. For near one surface the indudtion from 
that surface is at its strongest, that from the opposite sur- 
face at its weakest, since the latter has felt the resistance 
of all the molecules of the mass. Thus there is a slight 
difference in effeCt, and the surface charge may slightly 
penetrate into the interior. In good conductors, however, 
this effeCt is perhaps inappreciably small. 
The same principles apply to the contiguity of two oppo- 
sitely charged conductors. Each aCts upon the other as if 
