NOVUM ORGANUM 265 



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 missiles, as in darts, musket- 

 balls, and the like, we refer entirely to the motion of liberty. 



Let the eighteenth motion be that of trepidation, 90 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 dar 

 ing 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. 



Let the nineteenth and last motion be one which can 

 scarcely be termed a motion, and yet is one; and which we 

 may call the motion of repose, or of abhorrence of motion. 

 It is by this motion that the earth stands by its own weight, 

 while its extremes move toward the middle, not to an im 

 aginary centre, but in order to unite. It is owing to the 

 same tendency, that all bodies of considerable density 

 abhor motion, and their only tendency is not to move, 

 which nature they preserve, although excited and urged 



90 The motion of trepidation, as Bacon calls it, was attributed by the ancient 

 astronomers to the eight spheres, relative to the precession of the equinoxes. 

 Galileo was the first to observe this kind of lunar motion. Ed. 



