NOVUM ORGANUM 237 



with their degrees, are to be observed and examined in the 

 investigation of nature, either to a certainty, or by esti 

 mation, or comparison, as opportunity permits. 



XLY1. In the twenty-second rank of prerogative in 

 stances we will place the instances of the course, which 

 we are also wont to call water instances, borrowing our 

 expression from the water hour-glasses employed by the 

 ancients instead of those with sand. They are such as 

 measure nature by the moments of time, as the last in 

 stances do by the degrees of space. For all motion or nat 

 ural action takes place in time, more or less rapidly, but 

 still in determined moments well ascertained by nature. 

 Even those actions which appear to take effect suddenly, 

 and in the twinkling of an eye (as we express it), are 

 found to admit of greater or less rapidity. 



In the first place, then, we see that the return of the 

 heavenly bodies to the same place takes place in regular 

 times, as does the flood and ebb of the sea. The descent 

 of heavy bodies toward the earth, and the ascent of light 

 bodies toward the heavenly sphere, take place in definite 

 times, 77 according to the nature of the body, and of the 

 medium through which it moves. The sailing of ships, 

 the motions of animals, the transmission of projectiles, all 



77 We have already alluded, in a note prefixed to the same aphorism of the 

 first book, to Newton s error of the absolute lightness of bodies. In speaking 

 again of the volatile or spiritual substances (Aph. xl. b. ii.), which he sup 

 posed with the Platonists and some of the schoolmen to enter into the composi 

 tion of every body, he ascribes to them a power of lessening the weight of the 

 material coating in which he supposes them inclosed. It would appear from 

 these passages and the text that Bacon had no idea of the relative density of 

 bodies, and the capability which some have to diminish the specific gravity of 

 the heavier substances by the dilation of their parts ; or if he had, the reveries 

 in which Aristotle indulged in treating of the soul, about the appetency of 

 bodies to fly to kindred substances flame and spirit to the sky, and solid 

 opaque substances to the earth, must have vitiated his mind. Ed. 



