CERTAIN HARMONIES OF THE SOLAR SYSTEM. 



23 



same process of rending, the attraction of material outward, i.e., toward the more 

 dense Earth-forming mass, may itself have been efficient.^ 



3. The division of material into two half-planet portions, would very probably 

 take place, at what, with reference to the revolution around the sun, was the centre 

 (or rather the central line) of gyration of the whole mass (at the distance 8C in 

 the figure) ; leaving the material on the one side and the other of that limit, to be 

 gathered into the half-planet masses, 



each around its own special centre Fig- 8. 



of gyration (at C and C") ; which 

 special centre would be that due to 

 the half-planet itself, when formed. 



Making use, then, of the half- 

 planets themselves (gathered at C' 

 and G")^ and finding their centre 

 of gyration, we shall approximate 

 to the former position of ((7) the 

 centre of gyration of the whole 

 mass. But that would be the posi- 

 tion of the whole planet, if the 

 material had all gone to form it, 

 i.e., the limit (©?) in Table (B), 

 so that the centre of gyration of 

 the two half-planets should be found 

 very near to the limit (©?) in 

 Table (B), in (14). 



Now — with the masses of the Earth and of Venus as given in Table (A), in (3), 

 and their distances as given in the column of Law in Table (B) in (14) — from Eq. 

 C in (17), we have for the distance from the sun of the centre of gyration of the 

 Earth and Venus, 



with sun's horizontal parallax = 8".848, C = 0.88665 

 " " " " ==8.78, C = 0.88579. 



And the position due to the whole planetary limit (®?) in Table (B), in accord- 

 ance with Laxv ls< (10), is 



(©9) = 0.85101. 



4. But the separation of the material into two half-planet portions would, withal, 

 take place at the limit where the attractive forces of the forming half-planets were 

 in equilibrio ; on one side of which limit the material would be gathered (by the 

 excess of attractive force on that side) in the formation of a half-planet toward 

 that side ; and on the other side of (the neutral) limit, in the formation of another 



' A writer in the Wedminater Revieio, vol. Ixx. (July, 1858), has introduced the idea of a greatly 

 inclined rotation in a thick ring, or even a retrograde rotation ; but he has applied it in a region of 

 the system in which the conditions which he introduces are misplaced. A different explanation is 

 applicable in the instance of Uranus, as will be shown hereafter. 



*" Which will scarcely differ, in either case, from the very centre of the planet itself. 



