Nebular and Stellar Spectra. 389 



cluster -was any trace of bright lines [i. e. } the indication of 

 gaseous matter] detected." 



No. 20 (Int. Obs. vi. 117). 13 M. 4230 Gen. Cat. 

 " Spectrum ends abruptly in the orange. The light of the 

 brighter part is not uniform ; probably it is crossed either by 

 bright lines or by lines of absorption.-" 



No. 25 (Int. Obs. vi. 347). 56 M. 4485 Gen. Cat. "Sus- 

 picion of unusual brightness in the middle part of the 

 spectrum." 



No. 26 (Int. Obs. vi. 348). 81 M. 1949 Gen. Cat. "The 

 red end of the spectrum wanting or very faint." 



No. 27 (Int. Obs. vi. 348). 82 M. 1950 Gen. Cat. " The 

 absence or great faintness of the red portion of the spectrum 

 more marked than in the spectrum of No. 1949." 



No. 29 (Int. Obs. viii. 207). 51 M. 3572 Gen. Cat. "A 

 suspicion that some parts of the spectrum [of each of the 

 bright centres] were abnormally bright relatively to the other 

 parts." 



Such is the result of prismatic analysis applied to nebulae 

 and clusters with which we have been made familiar. In a 

 very remarkable and suggestive note the author states that the 

 peculiar appearance of the continuous spectra of some of the 

 nebulae and clusters has suggested to him, from his first 

 examination, that possibly the luminous points into which the 

 telescope resolves some of them, may not be of the same nature 

 as the true stars. The spectrum of the great nebula in 

 Andromeda and its small companion was recorded in August 

 1864 as ending abruptly in the orange: and throughout its 

 length not uniform, but evidently crossed, either by lines of 

 absorption, or by bright lines. The same characters, he adds 

 (as we have already seen), have since been found in several of 

 the brighter nebulae and clusters : it would be possible to 

 explain the absence of the less refrangible rays by absorption 

 through vapour ; but the apparently complete want of light at 

 that end, and the unequal, mottled appearance of the brighter 

 parts suggest rather a gaseous source ; and that the spectrum 

 consists of numerous bright lines : they are too faint, however, 

 to admit of a sufficient contraction of the slit to determine 

 this point. But some quite recent observations (June, 1866) 

 not yet complete, appear to support the view that the bright 

 points of some clusters may not be similar in constitution to 

 the sun, or the brighter stars. 



Thus it would seem that a new and unsuspected, and most 

 singular field of inquiry is opened to the view of those whose 

 instrumental means admit of its investigation. Such means, 

 indeed, are rare. But if, where they exist, they were pushed 

 to their full capability, much valuable aid might be given to 



