PORTION OF THE COSMOS. NEBULA. 245 



" Dumb-bell" from its apparent shape as seen with a reflector 

 of eighteen inches aperture (Phil. Trans., 1833, No. 2060, 

 fig. 26; Outlines, 881). The resemblance to a Dumb-bell 

 entirely disappeared when viewed with a 3 -feet reflector of Lord 

 Rosse ( 433 ), for whose recent and important representation of 

 this nebula see Phil. Trans. 1850, PL xxxviii. fig. 17. It was 

 resolved by the same telescope into numerous stars, inter- 

 spersed amongst still subsisting nebulous appearance. 



Spiral nebula in the northern Cants venations. This 

 nebula was first observed by Messier on the 1 3th of October, 

 1773 (on the occasion of the comet discovered by him) : it is 

 in the left ear of Asterion, very near the star n (Benetnasch) 

 in the tail of the Great Bear, (No 51 Messier, and 1622 of the 

 great Catalogue in the Phil. Trans. ] 833, p. 496, fig. 25). It 

 is one of the most remarkable phenomena in the firmament, 

 as well on account of its wonderful configuration, as of the 

 unexpected transforming effect exerted upon its appearance by 

 Lord Rosse' s 6-foot speculum. In the 18-inch reflector of Sir 

 John Herschel this nebula appeared globular, and surrounded 

 by a widely detached ring ; thus affording as it were an 

 image or counterpart of our sidereal stratum and Milky Way 

 ( 434 ). In the spring of 1845, however, the great telescope 

 of Lord Rosse transformed the entire object into a luminous 

 spiral, in which the convolutions are not symmetrically dis- 

 posed, but prolonged in one direction, and the two extre- 

 mities, one near the centre and the other towards the exterior, 

 terminate in dense, granular, rounded nuclei. Dr. Nichol 

 has published a drawing of this object (the same which was 

 presented by Lord Rosse to the meeting of the British Asso- 

 ciation at Cambridge in 1845) ( 435 ) ; but the most perfect 

 representation is that by Mr. Johnstone Stoney in the Phil. 



