Mr. Whelpley on the Idea of an Atom. 365 



with the two kinds of forces whose difference of distance occa- 

 sion the relation of gravity. Let two gravitant atoms, 

 C C 



p ; W, p' ; n' 



have the forces p p' developed in excess over those of n n' . They 

 will begin to repel each other, when that excess surpasses the 

 force of their mutual gravitation. But if p is developed more 

 than n, it must be at the expense of n. Now, take away the 

 cause of this excessive development of p or w, and the equilib- 

 rium will be instantly restored, and the forces be equals as before. 

 There are, then, two kinds of repulsion, that of pp' in excess, and 

 that of n n' in excess, corresponding with the repulsions of posi- 

 tively and of negatively excited bodies. 



Attraction will be occasioned by the excess of one of the powers^ 

 {p for example,) in one of the atoms. If n be in excess, the 

 force of p is proportionately diminished ; and the result is, that, 

 while the cause of this difference continues, repulsion pp' is di- 

 minished, as much as repulsion n n' is increased ; but, that at- 

 traction n p' is increased more than that of p n' is diminished — 

 a difference remaining in favor of the attraction p n'. This, then, 

 is the. cause of electrical attraction. But if the cause of this 

 disturbance is removed, a resolution instantly follows. Such 

 resolutions must take place across vacant space, for the atoms 

 C C develope each the forces of the other. Electric discharge 

 is this resolution of p n, and, that there is a constant tendency 

 to such a resolution, is proved, by the fact, that p n develope each 

 other equally in an isolated moving atom. 



General conclusions. 



If it is enquired, why the forces of an atom shoot into crystal- 

 line axes, the answer is, that if such an event is brought about 

 in one atom, it must of necessity happen in others that are in 

 immediate contact with it, for all forces develope each other.* 

 In physics, motion has neither beginning nor end, and the 

 cause of every motion is a previous one of the same kind. That 

 a nucleus may assume any state, it needs only to be in contact 



* It is at present necessary to assume, that when the nuclei are contracted to a 

 certain size, their forces will be axially developed : but the law is not without ex- 

 ceptions, and therefore must, (like gravity,) admit an analysis of its causes. 



Vol. xLviii, No. 2.— Jan.-March, 1845. 47 



