164 COSMOS 



The aisoovery of a fifteenth new planet (Eunomia) hat 

 just been announced. It was discovered by De Gasparis 

 upon the 19th of July, 1851. The elements, which have 

 been calculated by Riimker, are the following : 



Epoch of mean longitude in mean Greenwich time. ) o t 1 -f) 



Mean longitude 321° 25' 29" 



Longitude of perihelion 27 35 38 



Longitude of ascending node 293 52 55 



Inclination 11 48 43 



Eccentricity 0-188402 



Half major axis 2-64758 



Mean of motion 823-C30 



Period of revolution 1574 days. 



The mutual relation of the orbits of the asteroids and the 

 enumeration of the individual pairs of orbits has been made 

 the subject of acute investigation, first by Gould^ in 1848, and 

 more recently by D'Arrest. The latter says, " The strongest 

 evidence of the intimate connection of the whole group of 

 small planets appears to be, that if the orbits are supposed to 

 be represented materially as hoops, they all hang together in 

 such a manner that the whole group may be replaced by an^ 

 given one. If it so happened that Iris, which Hind discov- 

 ered in August, 1847, was still unknown, as many other bod- 

 ies in this region certainly are, the group would consist of two 

 separate parts — a result which must appear so much the more 

 unexpected, as the zone which these orbits occupy in the solar 

 system is wide."t 



We can not take leave of this wonderful group of planets 

 without mentioning, in this fragmentary enumeration of the 

 individual members of the solar system, the bold view of a 

 gifted and deeply investigating astronomer as to the origin of 

 the asteroids and their intersecting orbits. A result deduced 

 from the calculations of Gauss, that Ceres approaches extreme- 

 ly near to Pallas in her ascending passage through the plane 

 of that planet's orbit, led Olbers to form the conjecture that 

 " both planets, Ceres and Pallas, maybe fragments of a sin- 

 gle large principal planet which has been destroyed by some 

 natural force, and formerly occupied the gap between Mars 

 and Jupiter, and that the discovery of an additional number 

 of similar fragments which describe elliptical orbits round the 

 Sun, in the same region, may be expected."! 



* Benjamin Althorpe Gould (now at Cambridge, Massachusetts, 

 U. S.), Untersuchungen uber die gegeruseitige Lage der Bahnen zwischen 

 Mars und Jupiter, 1848, p. 9-12. t D'Arrest, op. cit., p. 30. 



X Zach, Monatl. Ccrresp., bd> vi., p. 88. 



