528 Mr. W. Huggins on the Spectra 



Minute points of light have been observed in this nebula by 

 Lord Rosse, Otto Struve, and others ; the spectra of these bright 

 points, especially if continuous like those of stars, are doubtless 

 invisible from excessive faintness. 



By suitable movements given to the telescope, different por- 

 tions of the image of the nebula formed in the telescope were 

 caused successively to fall upon the opening of the slit, which 

 was about ^ inch by -3^ inch. This method of observation 

 showed that the light from different parts of the nebula is iden- 

 tical in refrangibility, and varies alone in degree of intensity *• 



In addition to these objects the following were also observed : — 



[No. 4294. 92 M. R.A. 17 h 12 m 56 s -9. N.P.D. 46° 43' 31";2.] 

 In Hercules. Very bright globular cluster of stars. The bright 

 central portion was brought upon the slit. A faint spectrum 

 similar to that of a star. The light could be traced from between 

 C and D to about G. 



Too faint for the observation of lines of absorption. 



[No. 4244. 50 H. IV. R.A. 16 h 43 ra 6 S «4. N.P.D. 42° 8' 38"-8. 

 Very bright; large; round.] In Hercules. The spectrum 

 similar to that of a faint star. No indication of bright lines. 



[No. 116. 50h.31M. R.A.0 h 35« 1 3 s 9.N.P.D.49 o 29'45"-7.] 

 The brightest part of the great nebula in Andromeda was brought 

 upon the slit. 



The spectrum could be traced from about D to F. The light 

 appeared to cease very abruptly in the orange ; this may be due 

 to the smaller luminosity of this part of the spectrum. No in- 

 dication of the bright lines. 



[No. 117. 51 h. 32 M. R.A. h 35 m 5*-3. N.P.D. 49°54'12"'7. 

 Very very bright ; large ; round ; pretty suddenly much brighter 

 in the middle.] 



This small but very bright companion of the great nebula in 

 Andromeda presents a spectrum apparently exactly similar to 

 that of 31 M. 



The spectrum appears to end abruptly in the orange, and, 



* The author found, on November 23, 1864, that the light of the great 

 nebula in Orion is resolved by the prism into three bright lines. — Proceed- 

 ings of the Royal Society, vol. xiv. p. 39. 



During 1865 he discovered that the nebulae which follow have similar 

 spectra, consisting of one, two, or three bright lines, in addition to which, 

 in the case of some of them, a continuous spectrum was visible. 



2102. . . . 



27 H. IV. 



4499.... 



38 H. VI 



4234. . . . 



5 2. 



4827. . . . 



705 H. I. 



4403. . . . 



17 M. 



4627. . . . 



192 H. I. 



4572.... 



16 H. IV. 







— Proceedings of the Royal Society, vol. xv. p. 18. 



