274 THE NEBULAR HYPOTHESIS. 



true that this change in the ratio, depending on the degree 



of contraction each planet has undergone, has in no two 



cases been the same ; yet we may fairly conclude that 



where the ratio is still the greatest, it has been the greatest 



from the beginning. The satellite-forming tendency which 



each planet had, will be approximately indicated by the 



proportion now existing in it between the aggregating 



power, and the power that has opposed aggregation. On 



making the requisite calculations, a remarkable harmony 



with this inference comes out. The following table shows 



what fraction the centrifugal force is of the centrij^etal force 



in every case ; and the relation which that fraction bears 



to the number of satellites. 



Mercury. Yenus. Earth. Mars. Jupiter. Saturn. Uranus. 

 Ill 1 111 



362 282 289 326 14 6-2 9 



1 4 8 4 (or 6 ac- 



Satellite. Satellites. Satellites cording to 



and three Herschel.) 

 rings. 



Thus, taking as our standard of comparison the Earth 

 <vith its one moon, we see that Mercury and Mars, in which 

 the centrifugal force is relatively less, have no moons. Ju- 

 piter, in which it is far greater, has four moons. Uranus, 

 in which it is greater still, has certainly four, and probably 

 more than four. Saturn, in which it is the greatest, being 

 nearly one-sixth of gravity, has, including his rings, eleven 

 attendants. The only instance in which there is imperfect 

 conformity with observation is that of Venus. Here it ap- 

 pears that the centrifugal force is relatively a very little 

 greater than in the Earth ; and according to the hypothesis, 

 Venus ought, therefore, to have a satellite. Of this seem- 

 mg anomaly there are two explanations. Xot a few astron- 

 omers have asserted that Venus has a satellite. Cassini, 

 Short, Montaigne of Limoges, Roedkier, and Montbarron, 

 professed to have seen it \ and Lambert calculated its ele- 



