"In the present motions of the bodies which constitute the solar system there are motions in planes inclined to that equatorial plane.... The effort to eliminate the comets from the solar system, so as to avoid the responsibility of accounting for their origin, is a confession of the hypothesis [nebular hypothesis that all planetary motion began in one plane – the plane of the equator of the cosmical [[sphere] But the stability of the solar systems supposed to have been demonstrated by mathematical analysis."