390 SPECIAL RESULTS IN THE URANOLOG1CAL 



and the Cape of Good Hope by Sir John Herschel, and subse- 

 quently by Lamont at Munich, and Lassell at Liverpool. The 

 1st satellite of Uranus was rediscovered and observed by 

 Lassell from the 14th of September to the 9th of November, 

 1847, and by Otto Struve from the 8th of October to the 

 10th of December, of the same year ; and the outermost, or 

 6th satellite, by Lamont, on the 1st of October, 1837. The 

 5th satellite does not appear to have been seen again at 

 all; and the 3d not with sufficient certainty ( 635 ). These 

 details are not without importance, as suggesting fresh mo- 

 tives for not giving too much weight to so-called negative 

 evidence."* 



Neptune. 



The merit of the successful working out and earliest 

 publication of an inverse problem of perturbation, (viz. the 

 problem of deducing from given perturbations of a known 

 planet the elements of the unknown perturbing one), and 

 even of having occasioned, by a bold prediction, the great 

 discovery of Neptune by Galle, on the 23d of September, 

 1846, belongs to the acute powers of combination, and to 

 the persevering labours, of Le Verrier ( 636 ). It is, as Encke 

 has expressed it, the most brilliant of all planetary disco- 

 veries, because purely theoretical investigations caused the 

 antecedent prediction of the existence and the place of the 

 new and yet unknown planet. The promptitude of the 



* [See at the close of the present volume a note containing an account of 

 the discovery, by Mr. Lassell, of two more satellites of Uranus, communicated 

 to M. de Humboldt whilst the volume in the original was passing through 

 the press, but after this section had been printed. EDITOK.J 



