350 HUMBOLDT'S COSMOS : 



on Comets there is a full account of the extraordinary phe- 

 nomenon witnessed in January, 1846; the separation, or 

 splitting, of Biela's comet into two distinct bodies assuming 

 different lines of movement. Here Humboldt expresses the 

 anxiety, common to all. astronomers, for the evidence de- 

 rivable from the next return of these twin comets within our 

 sphere of observation. This return took place, as calculated, 

 in the autumn of 1852 ; the two nuclei were re-discovered, 

 one of them three weeks after the other; much farther 

 separated in space, and affording a strong presumption that 

 these two bodies are detached from one another for ever. 

 The phenomenon, as regards our knowledge, is unique and 

 not reducible to any ascertained law ; though, perhaps, not 

 wholly without relation to some of the aspects and changes 

 noted in certain other comets of our own time. 



We scarcely know whether to be satisfied or not with our 

 author's account of Mr. Adams's participation in the dis- 

 covery of the planet Neptune. The passages alluding to it, 

 both in the text and note's, have obviously been carefully 

 studied in the phrases employed; yet hardly give an ade- 

 quate explanation of the peculiar circumstances of this great 

 astronomical event. We quote from the text a few lines on 

 the subject. 



I think it right to forbear in this work from more than an 

 allusion to the certainly earlier, but unpublished labours not, 

 therefore, crowned by recognised success of the highly distinguished 

 and acute English geometrician, Adams, of St. John's College, Cam- 

 bridge. The historical facts relating to these labours, and to Le- 

 verrier's and Galle's happy discovery of the new planet, are related 

 circumstantially, impartially, and from well-assured sources of au- 

 thority, in two Memoirs, by the Astronomer-Eoyal, Airy, and by 

 Bernhard von Lindenau. Intellectual labours, directed almost at the 

 same time to the same great object, offer, besides the spectacle of a 

 competition honourable to both competitors, an interest the more vivid 

 because the selection of the processes employed testifies the brilliant 

 state of the higher mathematical knowledge at the present epoch. 



