Permanent Contraction of the Planetary Orbits. 101 



Airy and Herschel rightly said that Bode's law is not 

 founded upon any theory which correlates it either with 

 Kepler's laws, the gravitating force, or any other known 

 physical law. This want of connexion, however, is no 

 reason for rejecting it, any more than the law of gravitation 

 is to be rejected because natural philosophers are not yet 

 agreed whether the orbital moving force of planetary bodies 

 is to be measured by the simple velocity, or the square of 

 the velocity. 



Notwithstanding the departure from the law of multiple 

 proportions of the planetary distances in the case of 

 Neptune, where the difference between the theoretic and 

 actual numbers is as 38 to 30, no seriously reflective mind 

 can consider the approximate binary progression of dis- 

 tances shown in the table as entirely fortuitous. For, just 

 as the trained eye of a geologist, from his observation of a 

 few mammillated rocks and the distribution of moraine 

 matter, perceives with the certainty of a geometrical 

 demonstration the former existence of glaciers in many an 

 English valley, when all other record is obliterated, so 

 abundant evidence of exact purposive law is revealed in the 

 close approximation of the planetary distances to a law of 

 multiple proportions. 



I am quite sensible of the danger of importing teleologi- 

 cal arguments into strictly scientific discussions, from their 

 liability to abuse, but the idea of purposiveness comes out 

 so strongly in this law, from its complete isolation from all 

 known physical laws, the correlation of which originates 

 the idea of necessary connexion, that I was induced to 



Kelvin), after warmly supporting Sabine's conclusions so recently as April, 

 1891 {Popular Lectures and Addresses, vol, 3, p. 276), by an elaborate com- 

 putation, wholly unsupported by observational evidence, persuaded himself, in 

 the following year, that " the connection between sun-spots and terrestrial 

 magnetic disturbances is unreal, and that the seeming agreement between 

 the periods has been a mere coincidence." — Address delivered at the Anni- 

 versary Meeting of the Royal Society. Roy. Soc. Proc, vol. lii., p. 308. 



