Around the end of the 19th century, the view was widespread that all forces in nature are of electromagnetic origin (the " electromagnetic worldview "), especially in the works of Joseph Larmor (1897) and Wilhelm Wien (1900). This was apparently confirmed by the experiments of Walter Kaufmann (1901–1903), who measured an increase of the mass of a body with velocity which was consistent with the hypothesis that the mass was generated by its electromagnetic field. Max Abraham (1902) subsequently sketched a theoretical explanation of Kaufmann's result in which the electron was considered as rigid and spherical. However, it was found that this model was incompatible with the results of many experiments (including the Michelson–Morley experiment, the Experiments of Rayleigh and Brace, and the Trouton–Noble experiment), according to which no motion of an observer with respect to the luminiferous aether ("aether drift") had been observed despite numerous attempts to do so. Henri Poincaré (1902) conjectured that this failure arose from a general law of nature, which he called "the principle of relativity ". Hendrik Antoon Lorentz (1904) created a detailed theory of electrodynamics (Lorentz ether theory) that was premised on the existence of an immobile aether and employed a set of space and time coordinate transformations that Poincaré called the Lorentz transformations, including the effects of length contraction and local time. However, Lorentz's theory only partially satisfied the relativity principle, because his transformation formulas for velocity and charge density were incorrect. This was corrected by Poincaré (1905) who obtained full Lorentz covariance of the electrodynamic equations.