1868.] On the Spectra of some of the Southerm Nebulce. 



4-17. 



V. "Observations of the Spectra of some of the Southern Nebulae/^ 

 By Lieut. John Herschel, E.E. Communicated by W. Hug- 

 gins, Esq. Received May 20, 1868. 



[Lieut. Herschel, to whom the observations of the solar echpse of August 

 next have been entrusted by the Royal Society, has already employed the 

 instruments, placed in his hands by the Royal Society for the observations 

 of the eclipse, to good account by commencing an examination of some of 

 the brightest of the nebulse of the southern heavens. The first results of 

 this examination, which are contained in the present paper, were obtained at 

 Bangalore, Madras Presidency, during the months of March and April 1868. 

 The instruments consist of an equatorially mounted telescope of 5 inches 

 aperture, driven by a clock furnished with a pendulum-governor by Cooke 

 and Sons, and a spectroscope by Messrs. Simms furnished with one dense 

 prism of flint glass, and with a micrometev-screw and photographic scale for 

 measuring the lines. The nebulae No. 4390 and No. 2102 have been de- 

 scribed by me, Phil. Trans. 1864, p. 439, and Phil. Trans. 1866, p. 383. 

 — W. IL] 



No. 3531. [M 13^19^^: N.P.'D. 136° 37':!!; globular cluster of 

 stars ; w Centaur i.] 

 March 25. A large cluster visible to the naked eye, oval-shaped, brighter 

 towards the central part. Spectrum mi indefinahle haze ; no lines. 



No. 2197. [yll 10'^ 40^ : N.P.D. 148° 57' : great nebula in Argus.] 

 Spectrum : lines distinctly visible, but not clear enough to be separated ; 

 approximate position D + l-8 + '3 (D = 2-30, E= 3-68, 6 = 3'97, F=5-03). 

 An unsatisfactory observation : to be looked for again. 



No. 2017. [/RlO'^r^: N.P.D. 129° 47': !!; planetary nebula, very 

 bright, very large, little extended, * 9M.] 

 March 31. Found with difficulty in the spectroscope. After a minute or 

 two's examination the tube was accidentally disturbed, and before direction 

 could be again obtained, clouds had gathered and work was stopped. Appear- 

 ance in telescope : a nebulous-looking star ; under a higher power a nebu- 

 lous-looking object with a much brighter nucleus or centre. In spectroscope : 

 a conti?iuous streak with a blotch of light nearly in the middle of its lengthy 

 two-fifths, by estimation, from the red end ; slit quite wide. 



No. 2581. [/R 11^M4"^: N.P.D. 146° 27' : a planetary nebula, small, 

 round; blue=:*7M.] 

 April 2. A pretty ivell-defined and bright short line was distinctly 

 visible in the spectroscope, accompanied by a considerably fainter and more 

 refrangible companion. Principal line measured with the wires and found 

 to be D + 2-l = 4-4 (6 = 3-97, F = 5-03), i. e. 6-f 0-4. 



No. 4083. 15'^ 12"^ : N.P.D. 87° 25' : ! ! ; globular cluster, very bright, 

 large, extremely compressed in the middle.] 



