1889.] of the various Species of Heavenly Bodies. 197 



the comet approached the sun, the perihelion passage occurring on 

 June 10th. 



The perihelion passage occurred under such conditions that the 

 spectrum of the comet could not be satisfactorily observed on account 

 of the interference of daylight. Detailed observations, however, 

 were made when the comet was near perihelion and its temperature 

 sufficiently high to give bright lines. 



I have already discussed the spectrum of this comet when the lines 

 were best seen (May 31st), and the discussion shows that we had 

 remnants of the fluting of magnesium at 500, and of the blue carbon 

 band at 468. The line of carbon at 426 was probably also visible, and 

 the temperature was high enough for the appearance of iron. 



As the comet approached perihelion the conditions of observation 

 became less favourable. Between June 5th and June llth, the 

 perihelion passage occurring on June 10th, nothing but the D lines 

 were recorded. After June llth the comet was lost. 



The Great Comet of 1882. 



The spectrum of the Great Comet of 1882 was first observed on 

 September 18, a day after perihelion, by Copeland.* 



The spectrum consisted of bright and dark lines, among which was 

 the bright yellow line of sodium, several bright lines in the green, E, 

 and some prominent iron lines and five well-defined bright iines on 

 the red side of D. These have already been referred to. In addition 

 there were two dark lines on the redward side of 558 and 560, which 

 were most likely the edges of the first two maxima of the manganese 

 absorption fluting at 558. No more observations could be made at 

 Dun Echt until September 29, and in the interval most of the bright 

 lines in the spectrum had disappeared, whilst the carbon bands had 

 made their appearance. The D lines were still bright, but E and the 

 other lines had vanished. There was, however, something which is 

 described as " almost a line" at 610*3 ; this, no doubt, was the iron 

 fluting at 615. 



The next observations of the comet were made by Vogel,t on the 

 1st, 5th, 6th, and 7th October. On each of these occasions D was 

 still visible as a bright double line, in addition to the ordinary cometary 

 flutings. 



When the next observation was made on October 16th, by Hassel- 

 berg,J D had disappeared. On the 22nd and 23rd October, Copeland 

 again observed the spectrum, and it then consisted of -the three ordi- 

 nary cometary bands ; the citron band had a maximum at about 

 wave-length 557. Here Mn radiation had evidently commenced. 



* ' Copernicus,' vol. 2, p. 237. 

 t ' Astr. Nachr.,' No. 2466. 

 t ' Astr. Nadir.,' No. 2473. 



