NOVUM ORGANUM 249 



does not penetrate the pores of solid vessels at once, but 

 only by long-continued insinuation. 



Let the sixth be that which we term the motion of acqui 

 sition, or the motion of need. 81 It is that by which bodies 

 placed among others of a heterogeneous and, as it were, 

 hostile nature, if they meet with the means or opportunity 

 of avoiding them, and uniting themselves with others of 

 a more analogous nature, even when these latter are not 

 closely allied to them, immediately seize and, as it were, 

 select them, and appear to consider it as something acquired 

 (whence we derive the name), and to have need of these 

 latter bodies. For instance, gold, or any other metal in 

 leaf, does not like the neighborhood of air; if, therefore, 

 they meet with any tangible and thick substance (such as 

 the finger, paper, or the like), they immediately adhere to 

 it, and are not easily torn from it. Paper, too, and cloth, 

 and the like, do not agree with the air, which is inherent 

 and mixed in their pores. They readily, therefore, imbibe 

 water or other liquids, and get rid of the air. Sugar, or a 

 sponge, dipped in water or wine, and though part of it be 

 out of the water or wine, and at some height above it, will 

 yet gradually absorb them. 82 



Hence an excellent rule is derived for the opening 

 and dissolution of bodies; for (not to mention corrosive 

 and strong waters, which force their way) if a body can 

 be found which is more adapted, suited, and friendly to 

 a given solid, than that with which it is by some necessity 

 united, the given solid immediately opens and dissolves 



81 As far as this motion results from attraction and repulsion, it is only a 

 simple consequence of the last two. Ed. 



82 These two cases are now resolved into the property of the capillary tubes 

 and present only another feature of the law of attraction. Ed. 



