104 COSMOS. 



law of nature, which (like the beautiful law which connects 

 the square of the periods of revolution with the cube of the 

 major axes) represents the above-named elements of the order 

 of succession of the individual planetary bodies of each group 

 in their dependence upon the distances. Although the planet 

 which is nearest to the Sun (Mercury) is the densest, even 

 six or eight times denser than some of the exterior planets, 

 Jupiter, Saturn, Uranus, and Neptune, the order of succes- 

 sion, in the case of Yenus,' the Earth, and Mars," or Jupiter, 

 Saturn, and Uranus, is very irregular. The absolute mag- 

 nitudes do generally, as Kepler has already observed (Har- 

 monice Mundi, vol. iv., p. 194 ; Cosmos, vol. i., p. 93-97), 

 increase with the distances; but this does not hold good 

 when the planets are considered individually. Mars is small- 

 er than the Earth, Uranus smaller than Saturn, Saturn small- 

 er than Jupiter, and succeeds immediately to a host of plan- 

 ets, which, on account of their smallness, are almost im- 

 measurable. It is true the period of rotation generally in- 

 creases with the distance from the Sun ; but it is, in the case 

 of Mars, slower than in that of the Earth, slower in Saturn 

 than in Jupiter. 



The external world of forms, I again repeat it, can only 

 be represented in the enumeration of relations of space, as 

 something actually existing in nature, and not as the subject 

 of intellectual deductions of previously known causal rela- 

 tions. No universal law for the cosmical regions is here 

 traced, any more than for terrestrial regions in the culmina- 

 ting points of mountain chains, or. in the configuration of con- 

 tinents. These are natural facts which have resulted from 

 the conflict of numerous attractive and repulsive forces, un- 

 der conditions which are unknown to us. We here enter with 

 eager and unsatisfied curiosity upon the obscure domain of 

 incipient foTTnation. It is to t;hese phenomena that the so- 

 frequently misused term of natural facts may be applied in 

 its strictest sense, cosmical processes which have taken place 

 during spaces of time of, to us, immeasurable extent. If the 

 planets have been formed from revolving rings of nebulous 

 matter, it must, after having commenced to aggregate into 

 globes, according to the preponderating influence of individ- 

 ual centers of attraction, have passed through an intermina- 

 ble series of conditions in order to have formed sometimes 

 simple, sometimes interwoven orbits, planets of such diflerent 

 magnitudes, flattening, and density, with and without moons, 

 and even, in one case, to blend the satellites into a solid ring. 



