Letter, from Henry Oldenburg to Francis Vernon, dated at London Glad that Picard is going to perfect his observations to measure the earth; concerning the doctrine of motion; about the Parisian academics who are working on gravity and percussion; anticipating Cassini's ephemerides of the satellites of Jupiter and about the apogees of the planets; concerning Mercater's cycloid in pendulum watches; concerning Winthrop's gift of curiosities from New England 28 February 1670