III
ON THE DISTRIBUTION OF ELECTRICITY OVER
THE SURFACE OF MOVING CONDUCTORS
(Wiedemann's Annalen, 13, pp. 266-275, 1881.)
IF conductors charged with electricity are in motion re-
latively to one another, the distribution of free electricity at
the surface varies from instant to instant. This change pro-
duces currents inside the conductors which, on their part
again, presuppose differences of potential, unless the specific
resistance of the conductors be vanishingly small.
Hence we
may draw these inferences:-
1. That the distribution of electricity at the surface of
moving conductors is at each instant different from that at the
surface of similar conductors at rest in similar positions. In
particular, the potential at the surface and inside is no longer
constant, so that a hollow conductor does not entirely screen
its interior from external influence when it is in motion.
2. That the motion of charged conductors is attended by
a continual development of heat. Hence continual motions of
such conductors are possible only by a supply of external work,
and under the sole action of internal forces a system of such
conductors must come to rest.
The changes which the motion of conductors compels us
to make in the conclusions of electrostatics are especially
noticeable in those cases where the geometrical relations be-
tween the surfaces are invariable, that is, for surfaces of revolu-
tion rotating about their axes. Such bodies will have a
tendency to drag with them in their motion electrically.