THE PLANETS. 465 



peculiar causes, which may, perhaps, always remain unknown 

 to us. 



The orbits of the secondary planets which belong to the 

 same group, have very different degrees of excentricity. In 

 the Jovial system, the orbits of the first and second satellites 

 are nearly circular, while the excentricities of those of the 

 third and fourth satellites amount to 0'0013 and 0-0072. In 

 the Saturnian system, the orbit of the satellite nearest to the 

 primary (Mimas), is considerably more excentric than the 

 orbits of Enceladus and Titan, the largest and first discovered, 

 whose orbit was so accurately determined by Bessel. The 

 excentricity of the orbit of the sixth satellite of Saturn, is 

 only O02922. According to all these data, which are among 

 those that may be relied upon, Mimas only is more excentric 

 than the Earth's Moon (0-05484); the latter possesses the 

 peculiarity that its orbit round the Earth has a greater 

 excentricity, in comparison with that of its primary, than 

 any other satellite. Mimas revolves round Saturn in an orbit 

 whose excentricity is 0'068, while that of the orbit of its 

 primary is 0-056; but the orbit of our Moon has an 

 excentricity of 0'054, while the excentricity of that of the 

 Earth is only 0-016. With regard to the distances of the 

 satellites from their primaries, compare Cosmos, vol. i. 

 pp. 78-83. The distance of the satellite nearest to Saturn 

 (Mimas), is now no longer taken as 80,088 geographical 

 miles, but as 102,400 ; whence its distance from the ring, this 

 being calculated as 24,188 miles broad, and at a distance of 

 18,376 miles from the surface of the planet, will be 28,000 

 miles.* Remarkable anomalies, together with a certain 

 correspondence, are also presented in the position of the 

 orbits of the satellites in the Jovial system, in which very 



80 In the earlier data ( Cosmos, vol. i. p. 82) the equatorial 

 diameter was taken as a basis. 



