equal to it XCy, the angle ICk, and the place k, in which the body will then be found. Q. E. I.
We ſuppoſe in theſe propoſitions the centripetal force to vary in its receſs from the centre according to ſome law, which any one may imagine at pleaſure; but at equal diſtances from the centre to be every where the ſame.
I have hitherto conſidered the motions of bodies in immovable orbits. It remains now to add ſomething concerning their motions in orbits which revolve round the centres of force.
