PORTION OF THE COSMOS. ZODIACAL LIGHT. 413 



IV. 



RING OF ZODIACAL LIGHT. 



TN our richly varied Solar System, several of the distinct 

 classes of bodies of which it consists have only been recognised 

 by us in their existence, place, and form, at successive inter- 

 vals of time, in the last two centuries and a half. There 

 have thus been made known to us : First, subordinate or 

 particular systems, in which, in analogy with the chief or 

 general system of the solar domain, smaller cosmical sphereo- 

 dised bodies revolve around a larger one ; next, the exist- 

 ence of concentric rings surrounding one of the less dense 

 exterior planets, being also the one amongst them which is 

 most rich in satellites ; next, the existence and the probable 

 material cause of the mild, pyramidally shaped, Zodiacal 

 Light, very visible to the unassisted eye ; next, the mutually 

 intersecting orbits of what are called the small planets or 

 asteroids, situated beyond the zodiacal zone, and included 

 between the domains of two primary planets ; and lastly, 

 the remarkable group of inner comets, whose aphelia are less 



