Poincaré, the dynamics of the electron, and relativity

On 5 June 1905 Poincaré presented a Note to the Académie des Sciences entitled Sur la dynamique de l'électron (“On the dynamics of the electron”). After briefly recalling the context that led Poincaré to write this Note, we comment its content. We emphasize that Poincaré's electron model consists in assuming that the interior of the worldtube of the (hollow) electron is filled with a positive cosmological constant . We then discuss the several novel contributions to the physico-mathematical aspects of Special Relativity that are sketched in the Note, though they are downplayed by Poincaré, who describes them as having only completed the May 1904 results of Lorentz dans quelques points de détail (“in a few points of detail”).