36 Mr. J. N. Lockyer. Comparison of the Spectra of [Dec. 19, 



follows*: — "The carbon band at 5164 was coincident (within the 

 limits of observation with this dispersion) with the bright space 

 towards the bine of Band VI (Duner's band 7), and the sodinm lines 

 were clearly represented by two dark lines near the middle of Band II 

 (Duner's band 3), bnt the two manganese bands observed, not only 

 did not coincide with any great band of the spectrum, but were very 

 far distant from any of them. There were, indeed, faint lines about 

 the neighbourhood of either manganese band, but the entire spectrum 

 is full of such lines, and no fluting, nor anything corresponding to one, 

 could be detected near the place of these two bands. A third manga- 

 nese band was very close to Band II (Duner's band 3) of the stellar 

 spectrum." On the other hand, Yogel measured the position of the 

 sharp edge of a fluting in a-Orionis as 559*1, and Duner's measures 

 for the same vary from 557'5 to 559*3, none of which can be described 

 as " very far distant " from the manganese fluting near 558. Mr. 

 Maunder's observation can only be explained by assuming that the 

 band in question is variable. This might be produced by variations 

 in the intensity of the carbon flutings ; the manganese fluting falJs 

 on the carbon fluting near 564, and, according to their relative 

 intensities, the manganese fluting will be visible or will be marked 

 by the carbon. According to Gore, the star was at a minimum in 

 December, 1887. 



The fluting near 586 corresponds to Duner's band 2, for which 

 Duner measures wave-lengths varying from 585*4 to 585*1. It 

 apparently escaped Mr. Maunder's notice, at the time he made his 

 observations, that no reference was made in my paper of November, 

 1887, to any band in the star spectra which fell near the third fluting 

 of manganese near 535. The first two flutings, near 558 and 586, 

 fell so near to two of the dark bands in the spectra of the stars of 

 Group II that there was strong ground for believing them to be due 

 to manganese. This has since been abundantly confirmed by Mr. 

 Fowler's direct comparisons of the manganese flutings with the 

 spectra of several stars of the group. — December 9.] 



Under the heading of "Duner's Bands" I give the mean wave- 

 lengths measured by Duner for the dark bands, and the limits of the 

 bright spaces which are due to carbon. 



The figures first given refer to the sharp edges of the flutings ; 

 the other figures indicate approximately where the flutings fade 

 away. 



This comparison shows that there is a very close relation between 

 comets and Group II independent of the probable origins suggested. 

 Bright carbon flutings, the manganese fluting at 558, the lead fluting 

 at 546, the iron fluting at 615, and the magnesium fluting 521 are 

 common. 



* ' Greenwich Observations,' 1887, p. 22. 



