Ixxxii NOTES. 



the nebula also abounding with stars, and exhibiting the characteristics of 

 resolvability strongly marked." 



t 385 ) p. 22?. Compare Edinburgh Review, Vol. Ixxxvii. 1848, p. 186. 



C 386 ) p. 227. Kosmos, Bd. iii. S. 183 and 212, Anm. 84 (English edit. 

 p. 125, Note 250). 



C 38 ?) p. 227. Kosmos, Bd. iii. S. 44 (English edit. p. 35). 



(s 88 ) p. 228. Newton, Philos. Nat., Principia mathematics, 1760, T. iii. 

 p. 671. 



C 389 ) p. 228. Kosmos, Bd. i. S. 146 (Engl. edit. p. 131). 



(3 90 ) p. 228. Kosmos, Bd. i. S. 412, Anm. 66 (Engl. edit. Note 96). 



t 391 ) p. 228. Sir John Herschel, Cape Observations, 109111. 



P 2 ) p. 229. It may be proper to explain here the grounds on which this 

 enumeration is based. The three Catalogues of Sir William Herschel contain 

 2500 objects ; viz. 2303 nebulae, and 197 star-clusters (Madler, Astr. S. 448). 

 These numbers underwent alteration in a later and much more exact review 

 of the heavens by Sir John Herschel (Observations of Nebulae and Clusters 

 of Stars made at Slough with a Twenty-feet Reflector, between the years 

 1825 and 1833 -. Phil. Trans. 1833, p. 365481). About 1800 objects 

 were identical with those of the three earlier catalogues ; but from three to 

 four hundred were provisionally excluded, and more than five hundred newly 

 discovered ones had their Right Ascension and Declination determined 

 (Struve, Astr. stellaire, p. 48). The Northern catalogue contains 152 clusters 

 of stars, consequently 2307 152 = 2155 nebulas; but in the Southern cata- 

 logue (Cape Observ. p. 3, 6 and 7) we have to deduct from 4015-2307 

 = 1708 objects (among which there are 236 star-clusters) 233 (viz. 89 + 

 135 + 9 : see Cape Observ. p. 3, 6 and 7, and p. 128) as belonging to the 

 Northern catalogue, observed by Sir William and Sir John Herschel at Slough, 

 and by Messier at Paris. There thus remain for the Cape Observations, 

 1708- 233 = 1475 nebulae and clusters, or 1239 nebulas only. To the 2307 

 objects of the Northern catalogue of Slough we have to add, on the other hand, 

 135 + 9 = 144. Thus this Northern list becomes increased to 2451 objects, 

 containing, after deducting 152 clusters, 2299 nebulae; which numbers, how- 

 ever, do not apply to a very strict limit of the horizon according to the 

 height of the Pole at Slough. If in the topography of the firmament it 

 is deemed proper to assign numerical ratios to the two hemispheres, the 

 author thinks that it is right to do so carefully, although the numbers 

 in question must always be expected to vary at different epochs, and 

 according to the progress of observation. It belongs to the general design of 



