44 THE WOKLD-EKEBGY 



that it would seem as if (1) must be driven from (2) still 

 more powerfully than (2) is driven toward (1). At the 

 same time, however, it must be remembered that (1) is the 

 limiting particle of the series on one side. As such its 

 repulsion for (2) and for the remaining particles in the 

 series must be less than that of (2) for those remaining 

 particles. For the repulsion of (2) for (3), (4) and (5) 

 is intensified by the repulsion between (1) and (2), which 

 thrusts (2) back upon (3), but only to be the more pow- 

 erfully urged toward (1) again. 



Thus the tendency of the repulsion between (2) and 

 the particles of the series beyond (2) is to cause an actual 

 approach of (2) toward (1). And it is to be also noted, at 

 the same time, that the repulsion between (1) and (2) 

 counteracts in a measure the tendency toward separation 

 between (2) and (3) ; and so throughout the series. 



But, again, it has already been incidentally observed 

 that each intermediate particle in the series exerts its 

 repulsion in two precisely opposite directions. In the case 

 of (3), indeed, these repulsions in opposite directions 

 must balance each other. Hence, (3) is the point of 

 equilibrium in the series. And it is to be noticed especially 

 that the repulsion of this middle particle for those on either 

 side presents this peculiar aspect : that in thus exerting its 

 power of repulsion in opposite directions, it necessarily 

 concentrates upon itself. And this brings to explicit utter- 

 ance the truth that no particle, under any conditions 

 whatever, can push outward in any direction from itself 

 save by pressing in upon itself in the same act. 



Repulsion, then, even in so inadequate an example as 

 the one assumed, proves to be something more than a mere 

 tendency toward indefinite diffusion. Instead of being 



