XI. The Orbit and Motion of the Georgium Sidus determined directly from Observations, after a very easy and simple Method

Abstract

The accuracy of modern observations has discovered irregularities in the motions of Jupiter and Saturn, which our knowledge of the laws of planetary gravitation has not as yet enabled us to explain. I have, therefore, long thought it probable that there may be planets without the orbit of Saturn, of sufficient magnitude to occasion these irregularities. This conjecture is confirmed by the discovery of a new planet.