High Quality Content by WIKIPEDIA articles! De motu corporum in gyrum (Latin: "On the motion of bodies in an orbit") is the (presumed) title of a manuscript by Isaac Newton sent to Edmond Halley in November 1684. It followed a visit by Halley earlier in that year, when Halley had questioned Newton about problems then exercising the minds of Halley and his scientific circle in London, including Sir Christopher Wren and Robert Hooke.