324 On Electromagnetic Effects due to the Motion of the Earth. 
to one another exactly hke a quantity of electricity inside and outside a closed 
conductor, each induces on the conductor exactly such a charge as to neutralise its 
action on the other. The outstanding action on the conductor is exactly the same 
as if there were no internal charge at all. Hence it seems that the action ona 
magnet would be independent of its magnetization, and would be only that feeble 
force due to the electromagnetic action of the superficial induced charge. It is 
useless then to expect to obtain measurable forces by the action of electricity on 
magnets, when both are carried along by the earth. 
it seems hardly necessary to point out that the action of two conduction currents 
upon one another is unaffected by their common motion, as equal quantities or 
positive and negative electricities are present at each point, and there is con- 
sequently no convection action. 
I have throughout this investigation left out of account, as too small to be worth 
including, the self-induction of the displacement currents produced in the dielectrics. 
It is, however, very desirable that their action should be completely investigated, in 
order to see whether they can produce measurable effects, for instance in the case 
of powerful electromagnets. 
