THE STELLAR UNIVERSE. 



Another most extraordinary spiral nebula is shown in tig. o<3, p. 17. 

 It has been the subject of examination by all eminent observers 



Pig. 33. 



Fig. 34. 



since the time of Messier, in whose catalogue it is No. 99. The 

 spiral form of the nebula, represented in tig. 32, was discovered 

 by Lord Rosse, in the early part of 1845. In the spring of 1846, 

 that represented in the present figure was discovered. The spiral 

 form is here also presented, but of a different character. Lord 

 Rosse conjectures, that the nebula No. 2370, and 3239 of Herschel's 

 southern catalogue, are very probably objects of a similar cha- 

 racter. As Herschel's telescope did not reveal any trace of the 

 form of this nebula, it is not surprising that it did not disclose the 

 spiral form presumed to belong to the others, and it is not, there- 

 fore unreasonable to hope, according to his lordship, that whenever 

 the southern hemisphere shall be re-examined with instruments of 

 greater power, these two remarkable nebulae will yield some inte- 

 resting results. 



Lord Rosse has discovered other spiral nebulae, but they are 

 comparatively difficult to be seen, and the greatest powers of the 

 instrument are required to bring out the details. 



In fig. 36 is another nebula having the spiral character, and a 

 most singular form. Its situation is KA l h 24 m NPD 60 31', 

 and is therefore in the northern part of the constellation Pisces. 

 It is of great magnitude, having a diameter not less than half 

 that of the moon. This object has been the subject of observa- 

 tion by all the eminent observers* Sir John Herschel describes it 

 as enormously large, growing very gradually brighter towards 

 the middle, and having a star of the 12th magnitude, north , 

 following the nucleus, and being characterised by irregularities 





