22 COSMOS. 



« 



schel engaged at the Cape of Good Hope in exploring the 

 whole of the visible firmament with a colossal twenty-feet 

 reflector, and adding 1708 determinations of position to his 

 previous catalogue of 2307 nebulae and clusters of stars !* 

 Only one third of the southern nebulae and clusters of stars 

 in Dunlop's catalogue (containing 629 nebulous bodies, ob- 

 served from 1825-1827, at Paramatta, with a nine-feet re- 

 flector, having a nine-inch speculumf) were inserted in Sir 

 John Herschel's work. 



A third great epoch in our knowledge of these mysterious 

 cosmical bodies commenced with the construction of the mar- 

 velous fifty-three feet telescope^ of the Earl of Rosse, at Par- 

 sonstown. All that had ever been advanced on either side 

 of the question, during the long fluctuation of opinions in the 

 different stages of the development of cosmical contem.plation, 

 was now made the -subject of keen discussion in the contest 

 regardmg the nebular hypothesis and its asserted untenabil- 

 ity. It appears, from all the notices I have been able to col- 

 lect from the works of distinguished astronomers long accus- 

 tomed to the observation of nebulous spots, that out of a large 

 number of nebulae indiscriminately taken from among all the 

 classes contained in the catalogue of 1833, and regarded as 

 irresolvable, almost all (Dr. Robinson, the Director of the Ar- 

 magh Observatory, enumerates more than 40 such) have been 

 perfectly resolved. § Sir John Herschel maintains the same 



* The numbers which I here give include the objects enumerated 

 from Nos. 1 to 2307 in the European, Northern Catalogue of 1833, and 

 those from Nos. 2308 to 4015 in the African, Southern Catalogue. — Ob- 

 servations at the Cape, p. 51-128. 



t James Duulop, in the Philos. Transact, for 1828, p. 113-151. 



t Compare Cosmos, vol. iii., p. 65, and note. 



$ See ^« Account of the Earl of Rosse's great Telescope, -p. 14-17, 

 which gives a list of the nebulae resolved by Dr. Robinson and Sir James 

 South in March, 1845. " Dr. Robinson could not leave this part of his 

 subject without calling attention to the fact that no real nebula seemed 

 to exist among so many of these objects chosen without any bias : all 

 appeared to be clusters of stars, and every additional one which shall be 

 resolved will be an additional argument against the "existence of any 

 such." — Schumacher, Astr. Nachr., No. 536. In the Notice sur les 

 grands Telescopes de Lord Oxmantown, aujourd^hui Earl of Rosse {Bib- 

 Itothdque Universelle de Geneve, tom. Ivii., 1845, p. 342-357), we find the 

 following passage: " Sir James South rappelle que jamais il n'a vu de 

 representations sidexdales aussi magnifiques que celles que lui offrait 

 I'instrument de Parsonstown; qu'une bonne partie des nebuleuses se 

 presentaient comme des amas ou groupes d'etoiles, tandis que quelques 

 autres, k ses yeux du moins, n'ofFraient aucune apparence de resolution 

 en ^toiles." "Sir James South remarks that he never beheld more mag- 

 nificent representations of the stars than tliose he saw in the Parsoni*. 



