360 Literary and Philosophical Society. 



dation of properties observable in certain groups of elements 

 clearly shows that elementary species are not eternal, but 

 have a history which it is the proper object of physical 

 science to unfold. 



'One of the principal facts which to my mind establishes 

 the nebular theory of the formation of planetary systems on 

 a firm basis, is Bode's empirical law of the distances of the 

 members of the solar system from each other and from the 

 central body, as in this law is comprehended the idea of 

 nebular condensation in definite proportions. Now, if ele- 

 mentary species were created from a homogeneous substance 

 possessing a capacity for change in definite proportions, it 

 is probable that the greater number of elements would be 

 formed during, or after, the transition of the nebular matter 

 from the annular to the spheroidal form. Moreover, as 

 great cosmic transitions are not made per saltinUy it might 

 be expected that some modification of the law of nebular 

 condensation into planetary systems as exhibited in Bode's 

 law, would be found on the further condensation of the pri- 

 mitive matter into elementary species. 



* That relations such as I have indicated exist between 

 the nebular and elementary condensations, represented by 

 the planetary distances on the one hand, with the atomic 

 weights of well-defined groups of elementary substances on 

 the other, will be evident on comparing the numbers in the 

 following table : — 



I. 



O" o* 4 = 4 Mercury. 



1 X 3 + 4 = 7 Venus. 



2 X 3 + 4= 10 Earth. 

 4 X 3 + 4= 16 Mars. 



8x3 + 4 = 28 Ceres, Pallas, &c. 

 16x3 + 4 = 52 Jupiter. 

 32 X 3 + 4 = 100 Saturn. 

 64x3 + 4=196 Uranus. 



' In the above table the numbers expressing the relative 

 distances of the planetary bodies from the sun, and from 



