218 Mr. J. N. Lockyer. On the Spectra of 



length, and was found by direct comparisons to be coincident with 

 the carbon band near A 564. From this point of view, therefore, the 

 observations have not supplied us with any new facts, and, as the 

 comet is calculated to have passed perihelion on June 3, it is not 

 likely that any phenomena will be seen beyond the usual diminution 

 in brightness of the carbon flutings. 



The observations which have been made, however, showed such 

 a striking similarity between the spectrum of the comet and that of 

 the Nebula in Andromeda that advantage was taken of its presence 

 to compare its spectrum with that of an adjacent nebula, Gr. C. 4058 

 (R. A. 15 h. 3 m. 24 s., Decl. + 56 11'), which closely resembles the 

 Andromeda Nebula. 



In my paper of January, 1889 (p. 216), I referred to some observa- 

 tions of the spectrum of the Nebula in Andromeda which were 

 suggested by the discussion of cometary spectra. These observations 

 showed that the spectrum of the Nebula was really a cometary one ; 

 that is to say, that it consisted of the chief bands of carbon, with 

 a slight modification of the citron band. This result was first ob- 

 tained by Mr. Fowler in November, 1888, and was subsequently 

 confirmed by Mr. Taylor. The bright bands are superposed on a 

 continuous spectrum which is not much fainter, and they had conse- 

 quently escaped observation until specially looked for. The other 

 nebula with which a comparison has been made is comparatively 

 near to the comet, and, as its spectrum strongly resembles that of the 

 Nebula in Andromeda, it affords a good opportunity for observing the 

 similarity. 



The following extracts from the Observatory note-book will show 

 how close the resemblance is, and I communicate this note to the 

 Society in order that anyone possessing a telescope with an aperture 

 of 10 inches or more may see for himself while the comet is with us 

 that we are dealing with the radiation of carbon vapour in one case 

 as well as in the other : 



May 21. The comet was something like the Nebula in Andromeda 

 in general appearance, with the exception of the elongation. It was 

 whitish and round, but brightened in the middle to an ill-defined 

 nucleus. No further structure could be seen. With the direct- 

 vision spectroscope, a moderately bright continuous spectrum was 

 visible, with bright flutings superposed. The tiutings extended from 

 the nucleus to the boundaries of the comet, but they were very faint, 

 except in the nucleus itself, and there they were not very clearly 

 defined on account of the continuous spectrum. Made several direct 

 comparisons with the blue base of a spirit-lamp flame by means of the 

 microscopic glass reflector in front of the slit. The three flutings in 

 the spectrum of the comet were quite coincident with those in the 

 flame. The fluting near A. 517 was much brighter than the other two, 



