14-1 



1873.] J.rxi [Chase. 



The intermediate planets are arranged at distances proportioned to 

 orbital times at reciprocal centres of oscillation and suspension. Jupiter's 



mean distance is nearly 3- X Earth's; that of Uranus, (3 2 J 2 X that 

 of Venus. 



Intermediate Planetary Positions. 



Theoretical. Observed. 



Uranus 19.30* 19.19 



Jupiter 5.20 5.20 



Venus .72 .72 



The aphelion distances of Neptune, Uranus and Saturn, are at one ex- 

 tremity and centres of oscillation of a simple pendulum. The distance 

 of Uranus, or the mean length of the pendulum, represents the length of 

 a light undulation which is synchronous with a planetary oscilla- 

 tion at the Sun's surface. Jupiter's perihelion distance is one-sixth of 

 Neptune's. The significance of this coincidence is the more interesting, 

 in view of Stockwell's discovery that the mean perihelion longitudes of 

 Jupiter and Uranus differ by exactly 180°, and, therefore, Jupiter's peri- 

 helion is properly comparable with the aphelion of Uranus. 



The following table shows the accordance of these relations. 



Nodal Points op Planetary Oscillation. 



Theoretical. Observed. 



Neptune, mean aphelion 30.38 30.30 



Uranus, " " 20.26 20.05 



Saturn, " " 10.13 9.94 



Light, Undulation 20.26 20.20 



Jupiter, mean perihelion 4.96 4.98 



The principal planetary masses are so placed as to exhibit simple rela- 

 tions between their orbital moments of inertia. The mean moments 

 of Jupiter and Saturn are nearly equal ; Neptune's is about s times as 

 great as that of Uranus ; the sum of the moments of Venus and Mars 

 is about two-thirds as great as that of Earth and Mercury ; the centre of> 

 inertia of the planetary system is within the orbit of Saturn. 



Planetary Inertia. 



Jupiter, mean moment 258, 200 



Saturn, " " 259,627 



Uranus, " " X~ 482,378 



Neptune, " " 480,439 



| (Earth -f Mercury) 21.5 



Venus 4 Mars 20.8 



Mean centre of inertia 9.35 



Mean distance of Saturn 9.54 



* . 955 x 20. 20. See next table. 



