184 RADIATION FROM ELECTRONS [CH. xix. 



stability is impossible at any speed, so long as there 

 are only six present ; but if one of the six, or if a 

 seventh, be placed as a centre to the ring, then they 

 become stable again ; and at a proper speed there can 

 now be seven or even eight corpuscles in a ring, but not 

 more, unless more corpuscles be placed in the centre. 

 Suppose, for instance, that three be put in the centre : 

 they will there form a triangle, and round them there 

 may be a ring of as many as ten others. But to get 

 a stable ring of twelve corpuscles, you must have 

 seven inside altogether ; of which six or five can be in 

 another ring, with one or two at the centre of that. 

 By this means a large number of corpuscles, all in 

 rapid rotation, can be arranged in a series of rings ;. 

 but if the speed of any ring falls below a certain 

 critical value it becomes unstable, and then there 

 has to be a readjustment of corpuscles into another 

 pattern, which must give rise to a sudden con- 

 vulsion in the hypothetical structure of the atom. 

 This readjustment involves a decrease of potential 

 energy and consequent increase of kinetic energy, 

 and hence might result in the expulsion of some 

 corpuscles. 



Note that such a convulsion, on this theory, must 

 undoubtedly occur from time to time, though it may 

 be a rare occurrence in the life of any one atom ; 

 because revolving charges of electricity necessarily 

 radiate energy to some extent though usually to a 

 very small extent, and accordingly their speed must 

 gradually be reduced, until sooner or later it arrives at 

 the critical value at which a convulsion must occur. 

 The convulsion is followed by readjustment into 

 another pattern, and consequent transmutation into 

 another element, or at least into an allotropic form 

 of the first element if no fragment is lost ; and the 



