NOVUM ORGANUM. 193 



to equalize the pressure, is more correctly assigned to the 

 motion of liberty. 



Let the fifteenth motion be that of transmission, or of 

 passage, by which the powers of bodies are more or less 

 impeded or advanced by the medium, according to the na 

 ture of the bodies and their effective powers, and also ac 

 cording to that of the medium. For one medium is adapted 

 to light, another to sound, another to heat and cold, another 

 to magnetic action, and so on with regard to the other 

 actions. 



Let the sixteenth be that which we term the royal or 

 political motion, by which the predominant and governing 

 parts of any body check, subdue, reduce, and regulate the 

 others, and force them to unite, separate, stand still, move, 

 or assume a certain position, not from any inclination of 

 their own, but according to a certain order, and as best suits 

 the convenience of the governing part, so that there is a sort 

 of dominion and civil government exercised by the ruling 

 part over its subjects. This motion is very conspicuous in 

 the spirits of animals, where, as long as it is in force, it 

 tempers all the motions of the other parts. It is found in 

 a less degree in other bodies, as we have observed in blood 

 and urine, which are not decomposed until the spirit, which 

 mixed and retained their parts, has been emitted or extin 

 guished. Nor is this motion peculiar to spirits only, al 

 though in most bodies the spirit predominates, owing to its 

 rapid motion and penetration ; for the grosser parts predo 

 minate in denser bodies, which are not filled with a quick 

 and active spirit (such as exists in quicksilver or vitriol), so 

 that unless this check or yoke be thrown off by some con 

 trivance, there is no hope of any transformation of such 

 bodies. And let not any one suppose that we have forgotten 

 our subject, because we speak of predominance in this clas 

 sification of motions, which is made entirely with the view 

 of assisting the investigation of wrestling instances, or in 

 stances of predominance. For we do not now treat of 

 the general predominance of motions or powers, but of that 

 of parts in whole bodies, which constitutes the particular 

 species here considered. 



Let the seventeenth motion be the spontaneous motion of 

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

 placed in a favourable situation, enjoy their peculiar nature, 

 pursuing themselves and nothing else, and seeking as it 

 were to embrace themselves. For bodies seem either to 

 move without any limit, or to tend towards a limit, arrived 



VOL. xiv. o 



