Page:Poincaré - La Science et l’Hypothèse.djvu/298

 the failure of all experiments up to now, sufficiently justifies his view. Thus let us consider this impossibility as a general law of nature, let us take it as a postulate. Which consequences follow from that? This question was further investigated by Lorentz; he found that all atoms as well as all positive and negative electrons have an inertia, which (for all of them) varies with velocity by the same laws. Any material atom would therefore be composed by small and heavy positive electrons, and when the observable matter doesn't appear to us as electric, then this is caused by the fact that both kinds of electrons are present in approximately the same amount. They all have no measures, and their inertia is borrowed from the aether. In this system there is no actual matter, there are only holes in the aether.

According to Langevin, matter is liquefied aether that has changed its properties; when matter is moving, then it is not the liquefied mass that travels in the aether, but the liquefaction still affects new parts of the aether; and the aether that is located behind moving matter (and which was liquefied before) has returned to its earlier rigid state. Therefore, moving matter doesn't remain identical with itself.

This was the state of facts until recently; but now Kaufmann arrives with new experiments. The negative electron, whose velocity is extraordinarily great, must also suffer the contraction assumed by Fitzgerald, and by that the relation between velocity and