194 NOVUM OKGANUM. 



at which they either revolve according to their peculiar na 

 ture, or rest. Those which are favourably situated, and have 

 a tendency to motion 5 move in a circle with an eternal and 

 unlimited motion ; those which are favourably situated and 

 abhor motion, rest. Those which are not favourably 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 differences ; 1. with regard to the 

 centre about which the bodies move; 2. the poles round 

 which they move ; 3. the circumference 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 distance of these spirals from each 

 other ; 9. and lastly, the variation of the poles if they be 

 moveable ; which, however, only affects revolution when cir 

 cular. The motion in question is, according to common 

 and long received opinion, considered to be that of the 

 heavenly bodies. There exists, 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 the hypothesis of the earth s being 

 fixed) is confined to the heavens, or rather descends and is 

 communicated to the air and water. The rotation of mis 

 siles, as in darts, musket balls, and the like, we refer en 

 tirely to the motion of liberty. 



Let the eighteenth motion be that of trepidation, to which 

 (in the sense assigned to it by astronomers) we do not give 

 much credit ; but in our serious and general search after the 

 tendencies of natural bodies, this motion occurs and appears 

 worthy of forming a distinct species. It is the motion of 

 an (as it were) eternal captivity; when bodies, for instance, 

 being placed not altogether according to their nature, and 

 yet not exactly ill, constantly tremble, and are restless, not 

 contented with their position, and yet not daring to advance. 

 Such is the motion of the heart and pulse of animals, and 

 it must necessarily occur in all bodies which are situated 

 in a mean state, between conveniences and inconveniences; 

 so that being removed from their proper position, they strive 

 to escape, are repulsed, and again continue to make the 

 attempt. 



