510 COSMOS. 



The possibility of determining by calculation, even approxi- 

 matively, the epoch of such a cosmical event, which it is sup- 

 posed would be at the same time the epoch of the formation 

 of the small planets, remains more than doubtful, from the 

 complication produced by the already large number of the 

 " fragments " known, the secular retrogression of the apsides, 

 and motion of the nodes. 66 Olbers describes the region of the 

 nodes of the orbits of Ceres and Pallas, as corresponding to 

 the northern wing of the Virgin and the constellation of the 

 Whale. Certainly Juno was discovered, in the latter by 

 Harding, though accidentally, in the construction of a star- 

 catalogue, scarcely two years after the discovery of Pallas, and 

 even Vesta, in the former after a long search during five 

 years, conducted upon hypothesis. This is not the place to 

 determine whether these results alone are sufficient to esta- 

 blish the hypothesis. The cometary clouds, in which the 

 small planets were at first supposed to be enveloped, have 

 disappeared on investigation with more perfect instruments. 

 The considerable changes of light to which they were said 

 to be subject, were ascribed by Olbers to their irregular 

 figure as being "fragments of a single destroyed planet."* 7 



64 Gauss, Monatl. Corresp. Bd. xxvi. p. 299. 



67 Mr^ Daniel Kirkwood (of the Pottsville Academy) has 

 ventured upon the undertaking of restoring the exploded 

 primitive planet from the fragmentary remains in the same 

 manner as the animals of the primitive Earth. He finds for 

 it a diameter greater than Mars (of more than 4,320 geogra- 

 phical miles), and the slowest rotation of all the principal 

 planets a length of day of fifty -seven hours and a half. 

 (.Report of the British Asloc. I860, p. xxxv.) 



