CERTAIN HARMONIES OF THE SOLAR SYSTEM. 29 



tance of more than 64 radii of Saturn from his centre ; while the distance of the 

 outermost satellite of Jupiter, measured in the same way, is scarcely 27 radii of its 

 primary. 



And the comparatively feeble light of this same outermost satellite of Saturn is 

 withal consistent with a low density of that satellite;^ a fact also in place, in view 

 of the acquisition of a less dense material from the planetary region exterior to the 

 ancient Saturn \^ : the outermost satellite, in the view of the hypothesis as to its 

 formation, being most probably constituted of the portion the least dense of all. 



7. 



Such being the special form and constitution of the Saturn-forming mass — the 

 formation of the extensive system of satellites might have been nearly completed, 

 in advance of the ^'•abandonment" of the viaterial which now constitutes Saturn's 

 rings f or that satellite formation, at least have gone so far, as to keep the rings 

 in their forin and general arrangemeiit, while Saturn, condensing, shrank away 

 from the rings, yet with his central position with regard to them (or rather their 

 corresponding arrangement around him) preserved; the conservatire power of the 

 satellites, in these respects, being exerted in those very ancient times, even as now.^ 



It was then, it would seem, the drawing over and inward of the material which 

 else had constituted the half-planet between Saturn and Uranus, that, as has been 

 said, gave to Saturn and to his system the special form and arrangements that ren- 

 dered the retaining of the rings as rings a possibility; which has made them an 

 actuality; made Saturn what the author of the Novum Organum would term an 

 '•'■ instantia solitaQ'is," in the solar system. 



The same processes of the transference and combination of material here insisted 

 upon, seem also to have affected the inclination of Saturn'' s own equator, and that 

 of almost the whole Saturnian System, to the plane of the planefs orbit. 



For this great planet's equator, and his rings, and the orbits of his satellites* are 

 inclined at an angle of more than 28° with the plane of his orbit ; while the incli- 

 nation of Jupiter's equator, and that of the orbits of three of his satellites, does 

 not much differ from 8°. 



9. 



Another relation may possibly have some significance in this connexion; viz., 

 the ratio of the periodic time of the interior half-planet gj to the periodic time of 

 the ancient Saturn i^. 



' Not that the phenomenon of a comparatively feeble light would absolutely require the supposi- 

 tion of a low density ; but, as stated, the one thing would be consistent with the other. 



= There being material for that so far outward in the direction of the plane of the equator of the 

 very oblate spheroid, or near to that ; the spheroid being made so very oblate hij the acquisition from 

 without of the material of Si. 



' For " no planet can have a ring, unless it is surrounded by a sufficient number of properly-arranged 

 satellites. Saturn seems to be the only planet which is in this category ; and it is the only one, 

 therefore, which could sustain a ring." — Prof. Peirce, On the Constitution of Saturn's Ring, in the 

 Astronomical Journal No 27, p. IS. * All but that of the outer one. 



