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conductor, namely over its surface $\Sigma$, so that in the interior no electric force is acting. If we take this distribution for the system $S_{2}$ and derive from it a system $S_{1}$ by the above-discussed transformation, then also in this one an excess of positive ions only exists at a certain surface $\Sigma$, while in all interior points the electric force ${\mathfrak {E}}$ vanishes. The fact that an electric charge is located at the surface of a conductor, won't be changed by the translation of ponderable matter.

Similar considerations apply to two or more bodies. If a conductor C is confronted with a charged body K, then there exists, according to a known theorem, always a certain amount of charge on the surface of C, which together with K exerts no action on the ions in the interior of the conductor. This theorem remains valid, if the ponderable matter is moving, and it is even still allowed to assume that, under the influence of K, an "induced" charge is formed by itself upon C, which just cancels the effect of K on the interior points.

Since by (22) the components of ${\mathfrak {E}}$ are proportional to the derivative of ω, we can also say that inducing and inducted charges together cause a constant ω at all points of C. It follows then by means of equations (20), (21) and (V_a), that also a moving ion in the interior of C does not experience any force-action from the two charges.

Finally, it should be noted that by our formulas, the distribution of a charge over a given conductor, as well as the attraction or repulsion of charged bodies by the motion of the earth, must be changed. But this influence is limited to the second order, namely if the fraction ${\mathfrak {p}}/V$ is called a magnitude of first order, and thus the fraction ${\mathfrak {p}}^{2}/V^{2}$ is called a magnitude of second order.

Since ${\mathfrak {p}}/V=1/10000$, we may not hope, neglecting some very special cases, to find with respect to electrical and optical phenomena an influence of earth's motion that depends on ${\mathfrak {p}}^{2}/V^{2}$. The only thing that could be