ME. W. HUGGINS ON THE SPECTEA OF SOME OF THE NEBULiE. 
439 
[No. 4390. 2000 h. X 6. R.A. 18 b 5“ 17 s *8. N.P.D. 83° 10' 53"-5. A planetary nebula; 
very bright ; very small ; round ; little hazy.] In Taurus Poniatowskii. 
The spectrum is essentially the same as that of No. 4373. 
The three bright lines occupy the same positions in the spectrum, which was deter- 
mined by direct comparison with the spectrum of the induction spark. These lines 
have also the same relative intensity. They are exceedingly sharp and well defined. 
The presence of an extremely faint spectrum was suspected. In connexion with this 
it is important to remark that this nebula does not possess a distinct nucleus. 
The colour of this nebula is greenish blue. 
[No. 4514. 2050 h. 73 H. IV. R.A. 19 b 41 m 7 s -5. N.P.D. 39° 49' 41"-7. A planetary 
nebula with a central star. Bright ; pretty large ; round ; star of the 11th magnitude in 
the middle.] In Cygnus. 
The same three bright lines were seen. Their positions in the spectrum were verified 
by direct comparison with the induction spark. In addition to these a spectrum could 
be traced Rom about D to about G of the solar spectrum. This spectrum is much 
stronger than the corresponding spectrum of 4373. This agrees with the greater bright- 
ness of the central star, or nucleus. The opinion that the faint continuous spectrum is 
formed alone by the light from the bright central point was confirmed by the following 
observation. When the cylindrical lens was removed, the three bright lines remained 
of considerable length, corresponding to the diameter of the telescopic image of the 
nebula ; but the faint spectrum became as narrow as a line, showing that this spectrum 
is formed by light which comes from an object of which the image in the telescope is a 
point. 
Lord Posse remarks of this nebula, “ A very remarkable object, perhaps analogous 
to H. 450”*. 
The colour of this nebula is greenish blue. 
[No. 4510. 2047 h. 51 H. IY. R.A. 19 h 36 m 3 s -0. N.P.D. 104° 28' 52"-5. A planet- 
ary nebula. Bright ; very small ; round.] In Sagittarius. 
This nebula is less bright than those which have been described. The two brighter of 
the lines were well defined, and were directly compared with the induction spark. The 
third line was seen only by glimpses. I had a suspicion of an exceedingly faint spectrum. 
The colour of this nebula is greenish blue. 
Lord Rosse remarks, “ Centre rather dark. The dark part is a little north pre- 
ceding the middle ”f . 
[No. 4628. 2098 h. 1 H. IY. R.A. 20 b 56 in 31 s -2. N.P.D. 101° 55' 4"-8. An 
exceedingly interesting object. Planetary; very bright; small; elliptic.] In Aqua- 
rius. 
The three bright lines very sharp and distinct. They were compared for position 
with the induction spark. Though this object is bright, an indication only of the faint 
* Philosophical Transactions, Part III. 1861, p. 733. For a figure of H. 450 see Philosophical Transactions, 
1850, Plate XXXVIII. fig. 15. 
f Ibid. 1861, Part III. p. 732. 
MDCCCLXIV. 3 n 
