NOVUM ORGANUM 251 



any body separate themselves from the heterogeneous and 

 unite together, and whole bodies of a similar substance 

 coalesce and tend toward each other, and are sometimes 

 congregated, attracted, and meet, from some distance; thus 

 in milk the cream rises after a certain time, and in wine the 

 dregs and tartar sink; which effects are not to be attributed 

 to gravity and levity only, so as to account for the rising 

 of some parts and the sinking of others, but much more to 

 the desire of the homogeneous bodies to meet and unite. 

 This motion differs from that of need in two points: 1st, 

 because the latter is the stimulus of a malignant and con 

 trary nature, while in this of which we treat (if there be no 

 impediment or restraint), the parts are united by their 

 affinity, although there be no foreign nature to create a 

 struggle; 2dly, because the union is closer and more 

 select. For in the other motion, bodies which have no 

 great affinity unite, if they can but avoid the hostile body, 

 while in this, substances which are connected by a decided 

 kindred resemblance come together and are molded into 

 one. It is a motion existing in all compound bodies, and 

 would be readily seen in each, if it were not confined and 

 checked by the other affections and necessities of bodies 

 which disturb the union. 



This motion is usually confined in the three following 

 manners: by the torpor of the bodies; by the power of the 

 predominating body; by external motion. With regard to 

 the first, it is certain that there is more or less sluggishness 

 in tangible bodies, and an abhorrence of locomotion; so that 

 unless excited they prefer remaining contented with their 

 actual state, to placing themselves in a better position. 

 There are three means of breaking through this sluggish 

 ness heat; the active power of a similar body; vivid and 



