The electrons themselves do not escape this contraction, although the observer, since he participates in the same motion, naturally cannot notice it.

Lorentz supposes, besides, that all forces, whatever their origin, are affected by a translation in the same way as electromagnetic forces.

M.Langevin and M.H.
Poincare have studied this same question and have noted with precision various delicate consequences of it.

The singularity of the hypotheses which we are thus led to construct in no way constitutes an argument against the theory of Lorentz; but it has, we must acknowledge, discouraged some of the more timid partisans of this theory.[48] [Footnote 48: An objection not here noticed has lately been formulated with much frankness by Professor Lorentz himself.

It is one of the pillars of his theory that only the negative electrons move when an electric current passes through a metal, and that the positive electrons (if any such there be) remain motionless.