PLANETARY SYSTEMS. 79 



coincides with the plane of its orbit, and Jupiter, whose axis 

 of rotation is nearly perpendicular to it. 



in this enumeration of the forms which compose the world 

 in space, we have delineated them as possessing an actual ex- 

 istence, and not as objects of intellectual contemplation, or as 

 mere links of a mental and causal chain of connexion. The 

 planetary system in its relations of absolute size, and relative 

 position of the axes, density, time of rotation, and different 

 degrees of eccentricity of the orbits, does not appear to offer 

 to our apprehension any stronger evidence of a natural neces- 

 sity than the proportion observed in the distribution of land 

 and water on the Earth, the configuration of continents, or 

 the height of mountain chains. In these respects we can dis- 

 cover no common law in the regions of space or in the ine- 

 qualities of the earth's crust. They are facts in nature, that 

 have arisen from the conflict of manifold forces acting under 

 unknown conditions ; although man considers as accidental 

 whatever he is unable to explain in the planetary formation on 

 purely genetic principles. If the planets have been formed 

 out of separate rings of vaporous mattei revolving round the 

 Sun, we may conjecture that the different thickness, unequal 

 density, temperature, and electro-magnetic tension of these 

 rings may have given occasion to the most various agglomera- 

 tions of matter, in the same manner as the amount of tangential 

 velocity and small variations in its direction have produced 

 so great a difference in the forms and inclinations of the 

 elliptic orbits. Attractions of mass and laws of gravitation 

 have no doubt exercised an influence here, no less than in the 

 geognostic relations of the elevations of continents ; but we 

 are unable from present forms to draw any conclusions regard- 

 ing the series of conditions through which they have passed. 

 Even the so-called law of the distances of the planets from the 

 Sun, the law of progression, (which led Kepler to conjec- 

 ture the existence of a planet supplying the link that was 

 wanting in the chain of connexion between Mars and Jupiter) 

 has been found numerically inexact for the distances between 

 Mercury, Venus, and the Earth, and at variance with the con- 

 ception of a series owing to the necessity for a supposition in 

 the case of the first member. 



The hitherto discovered principal planets that revolve round 

 our Sun, are attended certainly by fourteen, and probably 



