474 Sir Oliver J. Lodge [Feb. 28, 



independence of intensity otherwise — seems to require a fair range of 

 frequency in those rays ; for their effect on a revolving electron would 

 naturally be to increase its angular speed and so throw it out of tune 

 with the particular disturbance to which it initially responded. The 

 sectorial area swept out would increase, the radius vector would 

 increase, the linear speed would therefore diminish in spite of the 

 resonant effort to increase ic. Unless indeed, under the pecuhar 

 conditions in an atom, there may be some compromise. The alter- 

 native would be for the electron to be constrained, under conditions 

 of stability, to maintain its frequency unaltered, either proceeding in 

 an outward spiral towards a position of Planckian instability, or 

 trying still to obey the law of inverse squares by increasing the ex- 

 centricity of its orbit with given axis major until it becomes practically 

 parabolic. {See Appendix II.) 



This could represent an inversion of the process by which the 

 electron may have been originally bound, according to Bohr's theory 

 of what happened before the atom became neutral. For it is to be 

 presumed that a positively charged a particle, after ejectment, 

 neutralises itself bv accretion and settles down. 



COXCLUSIOX. 



I have led you over a great deal of territory in a hurried manner, 

 and occasionally have entered on regions where the ground is not 

 yet solid and secure. Let it be granted that the chemist may 

 naturally object to an astronomical atom and may prefer a more static 

 or geometrical structure, although such a structure would have less 

 clear and explicable properties. The static or Boscovich atom, with 

 purely hypothetical interior fluctuations of force, leaves everything in 

 the dark, and is therefore less tempting to a physicist, until some 

 physical explanation of those fluctuations can be given. At present 

 they seem to be postulated merely in order to secure positions of 

 equilibrium in which an electron can settle down. Orbital revolution 

 achieves the same end, in apparently a more complicated but really a 

 more tractable manner. Moreover it confers upon an atom the sort 

 of energy and structural velocities which are conspicuous in the 

 various types of radio-activity. True, it is a working hypothesis 

 at present, and nothing more, but it seems likely to be a fruitful 

 one ; and that is its present justification. 



The subject is in the nascent or rapidly growing stage ; and, pro- 

 vided we refrain from dogmatism, it is legitimate thus tentatively to 

 survey and explore the boundary between knowledge and ignorance, 

 and to speculate as to what may be the next stages in the exhilarating 

 pursuit. 



The apparent resemblance between an atom and the solar 

 system opens up extraordinary vistas for further enquiry. Optics and 



