CHEMISTRY 99 



atoms it is the atoms themselves, and not the electrons, which 

 vary in mass. 



The electric and also the magnetic forces play no appre- 

 ciable part in the motions of the heavenly bodies. It may well 

 be, however, that the sun's positive electric charge just bal- 

 ances the negative charges of the planets, in which case the 

 solar system would represent a neutral atom. 



The scale by which the visible universe would have to be 

 reduced to get it down to microscopic dimensions is 10-- to 1. 

 The radius of the solar system is roughly 10^^ cm. This on 

 dividing by 10-- becomes 10'^ cm., the radius of an atom. 

 Neptune, one of the most detachable planets, may be likened 

 to a detachable electron. Its radius is about 10^ cm., and this 

 reduced in the same proportion, becomes 10"^^ cm., the radius 

 of an electron. The mass of Neptune bears about the same 

 ratio to that of the solar system that an electron bears to an 

 atom of oxygen. The analogy still holds good. The distance 

 between the sun and the nearest fixed star is about 10^^ cm., 

 and this divided by 10-- becomes 10'^ cm. or 0.001 mm. which 

 is the mean free path of a molecule of a gas on a high moun- 

 tain. If, besides reducing the linear dimensions from 10^^ 

 to 1, it is supposed that the present velocities of the planets be 

 maintained, some interesting results are obtained. Since Nep- 

 tune takes some 220 years to revolve once round the sun, 

 its "frequency" of revolution (that is, revolutions per second) 

 is 1.5 X lO"!*^. Since the path is reduced lO^^ times, the fre- 

 quency of describing it will be increased in the same propor- 

 tion and will become 1.5 x 10^-. This is the frequency of 

 some infra-red waves of light. The frequency of Mercury 

 will become 1.25 x 10^^ which lies in the ultra violet. All the 

 other planets will produce spectrum lines intermediate between 

 these, that is, lying in the visible spectrum. The asteroids 

 will produce a broad band instead of a line, and there will 

 be certain extra lines dues to perturbations of the planets by 

 each other. The solar system will present a spectrum much 



