182 THE WORLD-ENERGY 



plexity of relation between attraction and repulsion. 

 To this it is now to be added that the grouping 

 of particles known as crystallization, takes place for 

 each of the crystallizable substances at a single defi- 

 nitely fixed temperature of the substance, provided 

 always that the pressure is the same. That is, for every 

 crystallizable substance, the process of crystallization 

 can take place, only upon the establishment of a defi- 

 nite fixed relation between attraction and repulsion 

 within the substance. With any excess of repulsion 

 above that point, the crystals dissolve if already 

 formed, or refuse to form if the substance is in the 

 liquid state. 



Crystallization, then, is a special phase of the solid- 

 ification of bodies, a process which takes place only upon 

 the reduction of the repulsion between their particles to 

 such degree as to leave the attraction predominant, and 

 thus allow the particles to cohere in fixed relations. 

 These fixed relations again constitute a tendency to 

 break up a larger mass into a multitude of smaller 

 masses. Within the larger mass certain groups of par- 

 ticles combine into relatively small masses of perfectly 

 definite shape; the shape being fixed for each particular 

 kind of crystallizable matter. Thus the larger mass is 

 differentiated into a multitude of smaller masses, which 

 yet cohere in irregular groupings, leaving unoccupied 

 spaces between them, and thus thrusting the boundaries 

 of the entire mass outward on all sides. Thus, while 

 the matter in cooling to or below the point of crystal- 

 lization becomes more dense, and really occupies less 

 space, yet the bulk of the entire mass is increased; or, 

 in crystallizing, the body " expands," but without really 



