Mossotti-Lorentz Gravity

Everyone interested in gravity and the link between gravity and electrodynamics ought to read the 1900 paper by Hendrik Antoon Lorentz. An English translation can be downloaded from the digital library in the Hague in the Netherlands under the History of science and scholarship in the Netherlands. Starting in Section 5 of the paper Lorentz derives two sets of Maxwell equations for gravity based on the idea that gravity is nothing more than a small residual of electric forces wherein the attractive forces between unlike charges are just slightly larger than the repulsive forces between like charges. He gives full credit to Mossotti for this idea and credit to Weber and Zollner for further development. Naturally, the result looks like Newton's Law (like Coulomb's Law) but with extra terms. Lorentz calculated the effect of the modified theory on the orbit of Mercury; it was common knowledge that Mercury's orbit has a slow rotation of the slightly elliptical orbit that doesn't fit Newton's Law. Lorentz needed to select a speed and direction of the motion of the solar system through the medium. [Remember this was just before Poincaire, Einstein, and everyone else decided that they didn't need a medium for light propagation.] Lacking anything else, it seems that Lorentz chose the 'proper motion' of the sun, i.e., the motion of the sun with respect to the local group of stars in our neighborhood of the galaxy. The speed is about 16km/s. The number he obtained for the 'advance of the perihelion of Mercury', was way too small. It is interesting to note that if one uses a much larger value, like the speed of the solar system with respect to the microwave background radiation, one gets much closer to the observed value. There seems to have been only a little follow-up to Lorentz' paper. To me it seems a shame that the whole idea was not vigorously pursued.