264 NOVUM ORQANUM 



of revolution, by which bodies having a tendency to move, 

 and placed in a favorable situation, enjoy their peculiar 

 nature, pursuing themselves and nothing else, and seek 

 ing, as it were, to embrace themselves. For bodies seem 

 either to move without any limit, or to tend toward a limit, 

 arrived at which they either revolve according to their 

 peculiar nature, or rest. Those which are favorably situ 

 ated, and have a tendency to motion, move in a circle with 

 an eternal and unlimited motion; those which are favor 

 ably situated and abhor motion, rest. Those which are 

 not favorably situated move in a straight line (as their 

 shortest path), in order to unite with others of a congenial 

 nature. This motion of revolution admits of nine differ 

 ences: 1, with regard to the centre about which the bodies 

 move; 2, the poles round which they move; 3, the circum 

 ference or orbit relatively to its distance from the centre; 

 4, the velocity, or greater or less speed with which they 

 revolve; 5, the direction of the motion as from east to 

 west, or the reverse; 6, the deviation from a perfect circle, 

 by spiral lines at a greater or less distance from the centre; 

 7, the deviation from the circle, by spiral lines at a greater 

 or less distance from the poles; 8, the greater or less dis 

 tance of these spirals from each other; 9, and lastly, the 

 variation of the poles if they be movable; which, however, 

 only affects revolution when circular. The motion in ques 

 tion is, according to common and long-received opinion, 

 considered to be that of the heavenly bodies. There ex 

 ists, however, with regard to this, a considerable dispute 

 between some of the ancients as well as moderns, who have 

 attributed a motion of revolution to the earth. A much 

 more reasonable controversy, perhaps, exists (if it be not a 

 matter beyond dispute), whether the motion in question (on 



