NEBULA. 305 



maintains the same vipjy, as well in his opening address 

 before the British Association at Cambridge in 1845, as in 

 the Outlines of Astronomy, 1849, where he expresses him- 

 self as follows : "The magnificent reflecting telescope con- 

 structed by Lord Rosse, six feet in aperture, has resolved or 

 rendered resolvable multitudes of nebulae which had resisted 

 all inferior powers. . . . Although, therefore, nebula? do exist 

 which, even in this powerful telescope, appear as nebula?, 

 without any sign of resolution, it may very reasonably be 

 doubted whether there be really any essential physical dis- 

 tinction between nebula? and clusters of stars." * 



sur les grands Telescopes de Lord Oxmantoivn, aujourd'hm 

 Earl of Rosse (Bibliotheque universelle de Geneve, torn. Ivii. 

 1845, pp. 342-357), we find the following passage: "Sir 

 James South rappelle que jamais il n'a vu de representations 

 sideriales aussi magnifiques que celles que lui offrait 1'instru- 

 ment de Parsonstown; qu'une bonne partie des nebuleuses 

 se presentaient comnie des amas ou groupes d'etoiles, tandis 

 que quelques autres, a ses yeux du moius, n'ofiraient aucune 

 apparence de resolution en etoiles." "Sir James South 

 remarks that he never beheld more magnificent representa- 

 tions of the stars than those he saw in the Parsonstown 

 telescope, and that a great number of nebula? appeared like 

 clusters or groups of stars, whilst others, at least to his 

 sight, presented no appearance of resolution." 



26 See Outlines, pp. 597, 598 ; also the Report of the 

 Fifteenth Meeting of the British Association held at Cambridge 

 in June, 1845, p. xxxvi. : " By far the major part," savs 

 Sir John Herschel, " probably, at least, nine-tenths, of the 

 nebulous contents of the heavens consist of nebula? of spherical 

 or elliptical forms, presenting every variety of elongation and 

 central condensation. Of these a great number have been 

 resolved into distant stars (by the reflector of the Earl of 

 Rosse) and a vast multitude more have been found to present 

 that mottled appearance which renders it almost a matter of 

 certainty that an increase of optical power would show them 



