In Nº 13 of the Information Bulletin for the Southern Hemisphere I have given an outline of this method. Let there be thee mass points S = Sun, J = Jupiter, and A = Asteroid (or Satellite) and let us suppose that the orbital plane of Jupiter is taken as a fixed plane of reference in which a frame of fixed axes has been chosen in such a way that the X axis is oriented towards the perihelion of Jupiter. This system will be called “System I”.