the Distances between the Planets and Sun. 465 



It will be seen that this Table corresponds to our anticipa- 

 tions, except in the case of Saturn, where the difference is — 

 instead of + , and of the Earth, which is nearer to the Sun 

 than we should expect from the relative distances of Mars and 

 Venus. But in both these cases a probable explanation of the 

 anomaly is supplied by the circumstance of these planets re- 

 spectively possessing a greater amount of satellitary attendance 

 than their companions. If the satellites have been formed 

 during the consolidation of their primaries, it must be supposed 

 that there was something in the masses composing the Earth 

 and Saturn giving them a greater tendency to throw off satel- 

 lites than that belonging to their neighbours. It is probable 

 that this something was connected with a greater spheroidicity 

 in the form of the consolidating masses. Hence, since every 

 planetary mass must for a long time have moved in a medium 

 offering a considerable resistance, the form of the masses which 

 have produced Saturn and the Earth would retard their move- 

 ments more than those of their more spherical companions, and 

 thus diminish the relative magnitude of their orbits. 



Thus the anomalies in the distances of Saturn and the Earth 

 strengthen instead of embarrassing the hypothesis suggested, 

 being such as, from the peculiarities of these planets, must be 

 expected to exist if the hypothesis be true. It remains to explain 

 the position of Mercury. Now, since the distance from Mercury 

 to Juno is, according to the theory, one-twelfth of that from 

 Juno to Neptune, the symmetry of the system requires that the 

 distance between Mercury and the Sun should be one- twelfth 

 of that between Mercury and Juno. But if the great extension 

 of the orbit of Venus beyond that theoretically assigned to this 

 planet is due to the expansive force of the heat produced during 

 the latter stages of the process of solar condensation, the orbit 

 of Mercury ought to show a still greater expansion, as is the 

 case. For while, according to the theory, the normal place of Mer- 

 cury is represented by 2, its actual place is represented by 3*87, 

 equal to an expansion of 93 per cent. Thus do theory and ob- 

 servation again accord. 



I subjoin a Table exhibiting the distances of each planet from 

 the Sun according to the theory and to observation, and the dif- 

 ferences between the two sets of places in terms of the Earth's 

 radius, and in those of the theoretical radius for each planet, — the 

 proportions stated above being considerably modified when the 

 orbit of Mercury is taken into account, in consequence of its great 

 expansion. 



