1868.] Examination of Southern Nehulce luith the Spectroscope. 451 



IX. "Results of Examination of Southern Nebulae with the Spec- 

 troscope/^ By Lieut. J. Herschel. Communicated by Prof. 

 G. G. Stokes, Sec. R.S. Received June 1, 1868. 



No. 1179. April 9, 1868. [Great nebula in Orion.] All three lines seen 

 remarkably well, and measured as follows : — 



^.ggl 4-65;477l 4.g2. 5.24. D = 2-46. 

 4-67J ^^^j 



[Note.— 5=1) + \'67, Y = b-{-\'06.'] 

 No. 1225. April 9. [''Planetary; pretty bright ; very small ; very Httle 

 extended ; barely resolvable ?"] Not found. 

 April 4. Seen ; faint, but unmistakeable. Not seen in spec- 

 troscope, though most carefully placed and intently looked 

 for. 



No. 1565. March 30. ['' Planetary ; pretty bright ; pretty small; ex- 

 tremely little extended ; barely resolvable ; 3'-75 diam."] 

 Not seen. 



April 18. Seen, but not considered bright enough : some 



doubt about identity. 

 April 23. What was seen on the 18th looks more than ever 

 doubtful : a faint haze in a cluster. 

 No. 1567. April 23. ['* Planetary ; considerably bright ; not very well 

 defined."] Linear spectrum, 

 4-66, D=2'50 



No. 1783*. ["Remarkable; planetary; pretty bright; = star 



9 mag. ; very small ; round."] Looked for three times, but 

 not seen. 



No. 1801. [''Remarkable; planetary; pretty bright; pretty 



large ; round."] Looked for twice, but not seen. 



No. 2008. April 12. [" Very bright ; large ; very much extended, 45°."] 

 Well placed, but not seen with spectroscope ; focus sus- 

 pected, but not enough to prevent lines being seen. 

 April 23. Easily visible in telescope. I am almost certain I 

 must have seen this one if it has a linear spectrum. Conti- 

 nuous spectrum suspected. 



No. 2017. March 31. ["Very remarkable; planetary; very bright; very 

 large; little extended ; star 9mag. in the middle ; 4'-0diani."] 

 Slight haze and moonlight. Found with difficulty in spec- 

 troscope : examination interrupted. A continuous streak 

 with blotcli of light f from the red end. 



No. 2102. April 4. ["Remarkable; planetary; very bright; little ex- 



* 1783. May 4. Seen as a monochromatic light — faint, but beyond doubt. Rough 

 measurement, D-f-2"0» 



VOL. XVI, 2 R 



