PORTION OV THE COSMOS. THE SOLAE DOMAIN. 259 



. The Solar Domain. 



Planets and their satellites, comets, ring of zodiacal 

 light, and meteoric asteroids. 



When in the Uranological portion of the physical descrip- 

 tion of the Universe we descend from the heaven of the 

 fixed stars to our solar and planetary system, we pass from the 

 great and universal to the relatively small and special. The 

 domain of the Sun is the domain of a single fixed star 

 among the myriads which the telescope discloses to our 

 view ; it is the limited space within which cosmical bodies 

 of very different kinds, obeying the immediate attraction of 

 one central body, revolve around the same in wider or nar- 

 rower orbits, either alone or accompanied by other bodies 

 similar to themselves and revolving round them. In the side- 

 real portion of Uranology which I have attempted to treat 

 in the earlier part of the present volume, I have indeed de- 

 scribed among the millions of telescopic fixed stars, one 

 class, that of double stars, which also presents particular 

 systems, either binary or consisting of more than two mem- 

 bers : but these, notwithstanding the analogy of their 

 impelling forces, are yet in their nature different from our 

 solar system. In them, self-luminous fixed stars move 

 around a common centre of gravity which is not occu- 

 pied by visible matter; in the solar system, dark cos- 



