384 MR. w. lira GINS on the spectra of some of the nebula. 



unable to ascertain satisfactorily whether any other fainter lines were also present in 

 the spectrum. 



Sir John Hekschel describes its appearance as " somewhat hazy, with a slight nebu- 

 lous atmosphere"*. 



D'Aebest's measures of the diameter are — January 13, 1856, =25", and March 11, 

 1856, =27" f. 



[On March 14, 1866, I examined this nebula with my refractor of 8 inches aperture. 

 Powers of 600 and 920 diameters showed that the nebula is annular. It appears to 

 consist of an oval ring of brighter matter surrounded by a broad margin of faint nebu- 

 losity. The area enclosed by the ring, like that of the annular nebula in Lyra, is filled 

 with faintly luminous matter. The faint nebulosity surrounding the ring appears cir- 

 cular, or nearly so, suggesting that the ring, seen obliquely from our system, exists 

 within a globular mass of faint nebulous material. 



When the spectroscope was applied, in addition to the bright line seen in 1865, the 

 two other bright lines which are present in many nebulae, were also observed. When 

 the slit was made sufficiently narrow for these bright lines to appear defined, no trace 

 of a continuous spectrum was detected. With a wide slit, however, I suspected a faint 

 and broad continuous spectrum. — June 1866.] 



[No. 4234. 1970 h. 5 2. E. A. 16'' 38'° 36'. N.P.D. 65° 56' 10". A planetary nebula ; 

 very bright ; very small ; disk and border.] 



I observed this nebula, and all the objects which follow in this paper, with my 

 refractor of 8 inches aperture. 



On this nebula powers up to 1000 diameters were employed. With low powers this 

 object appeared small, round, intensely bright, and decidedly blue in colour. Higher 

 powers showed a uniform disk surrounded with a faint nebulous halo. 



The prism resolves the light of this nebula into three bright lines, occupying the 

 same positions in the spectrum as the bright lines of nebula No. 4373 J. The two 

 brightest lines are bright, and differ not very greatly in intensity ; the less refrangible 

 of the lines is the brighter. The most refrangible of the three lines is much fainter 

 than the others. 



A very faint continuous spectrum was seen by glimpses. 



Lord RossE describes this nebula : — " Intense blue centre fading off to some distance 

 all around. I found once or twice there were projections. (N.B. The existence of these 

 not satisfactorily proved "§.) 



Sir John Herschel gives its diameter =8" ||. 



D'Aebest's measures of its diameter are — 1856, March 12, =6", June 1, =8"^. 



• Results of Astronomical Observations at the Cape of Good Hope, p. 94, and pi. 6, fig. 5. 



t Resultate aus Beobachtungen der Nebelflecken und Stemhaufen, p. 326. 



J Philosophical Transactions, 1864, p. 438. § Ibid. 1861, p. 732. || Ibid. 1833, p. 458. 



% Beobachtungen der Nebelflecken und Stemhaufen, p. 341. 



