Non-spherical earth

Earth shape suggested as oblate spheroid. When Richer traveled to Cayenne to determine Mars parallax, found pendelum beats slower there than in Paris. Newton suggested that this was due to difference in gravity at equator vs. at poles. This would mean earth would bulge.
 Isaac Newton England 1687 Non-spherical earth

Earth shape suggested as oblate spheroid. When Richer traveled to Cayenne to determine Mars parallax, found pendelum beats slower there than in Paris. Newton suggested that this was due to difference in gravity at equator vs. at poles. This would mean earth would bulge.