ME. "W. HUG GINS ON THE SPECTEA OF SOIVIE OF THE NEBULJi:. 387 



The spectrum of this nebula, or at least of some parts of it, is almost certainly of the 

 order which indicates that the source of the light is gaseous matter. I believe that the 

 spectrum consists of one bright line. The object, however, is very faint, and the deter- 

 mination of its spectrum with my instrument very difficult. I examined the light of 

 this nebula several times, with eyepieces of different powers applied to the small tele- 

 scope of the spectroscope, but in all the observations I was confirmed in the opinion 

 that the greater part at least of the light is monochromatic. 



Probably there is, in addition to the bright line or lines, a faint continuous spectrum, 

 which may belong to the stars which are visible within the nebula. 



[No. 4827. 2178 h. 705 H. II. R.A. 22'- 35™ 6»-6. N.P.D. 29° 27' 5"-4. Bright; 

 small ; round ; gradually very little brighter in the middle ; easily resolvable.] 



" Planetary ?"— Lord EosSE ♦. 



" Three stars preceding. Resolvable ]" — Lord Oxmantown. 



One bright line only was distinctly seen in the spectroscope. 



On account of the faintness of the object, I am unable to say whether any other 

 fainter lines are also present, or a faint continuous spectrum. 



[No. 4627. 2099 h. 192 H. I. R.A. 20'' 56"" 17^-5. N.P.D. 35° 59' 39"-6. Con- 

 siderably bright ; large ; barely resolvable ; two stars attached.] 



" Has an appearance of two nuclei or points of greatest condensation ; it touches a 

 fine double star." — Sir Johx Herschel f . 



" The nebula has three knots in it." — Lord Rosse J. 



" No mention of resolvability." — Lord Oxmantown. 



The different knots of this nebula give a spectrum indicating gaseity, though in the 

 examination of some parts of the nebula I suspected the presence of a faint continuous 

 spectrum as well. The continuous spectrum may possibly belong to the small stars which 

 are represented in Lord Rosse's drawing of this object. 



One bright line only was distinctly seen, of apparently the same refrangibility as the 

 brightest of the nitrogen line. This bright line appeared by glimpses to be double. 

 Possibly this appearance was due to the presence near it of a second line. The faintness 

 of the light did not permit the slit to be made sufficiently narrow for the determination 

 of this point. 



[[No. 385. 76 M. R.A. 1" SB"' 28'-5. N.P.D. 39° 8' 52"-4. Very bright ; preceding 

 of double nebula. 



No. 386. 193 H. 1. R.A. 1" 33" 37^-5. N.P.D. 39° 7' 27"-4. Very bright; following 

 of double nebula.] 



Both parts of this double nebula give a gaseous spectrum. The brightest only of the 

 three lines usually present was certainly seen. The second line is probably also present. 



I suspected a faint continuous spectrum at the preceding edge of No. 386. 



• Philosophical Transactions, 1861, p. 735. t Ibid. 1833, p. 469. 



t Ibid. 1861, p. 734, and Plate XXX. fig. 37. 



