1888.] of the various Species of Heavenly Bodies, 



4L 



of the spectrum as it appeared to him, and a curve showing the 

 variation of intensity of the light throughout the spectrum. 



The wave-lengths given by Yogel are 582 and 570, and a band 

 with its brightest part at 464, fading off in both directions and 

 according to the sketch having its red limit at 473. In the light 

 curve Vogel not only shows the 582 and 570 lines, but also bright 

 lines in positions which by a curve have been found to correspond to 

 wave-lengths 540 and 636. Yogel indicates in his sketch a dark 

 band extending from 486 to the bright band 473, and an apparent 

 absorption on the blue side of the 570 line, this absorption being 

 ended at 564. These two bands agree in position with the dark 

 spaces observed by Messrs. Wolf and Rayet. The bright band in the 

 blue at 473 is most probably the carbon band appearing bright upon 

 a faint continuous spectrum, this producing the apparent absorption 

 from 486 to 473. If the bright carbon really accounts for the appear- 

 ance of a (contrast) dark band between the bright 570 and 564 in this 

 star, all the apparent absorption is explained as due to contrast 

 of bright bands on a fainter continuous spectrum due to red-hot 

 meteorites. 



The line at, 540 is the only line of manganese visible in the bunsen 

 burner, and the 580 line is the strongest low-temperature iron line. 

 The 570 Hue is most probably the green sodium line 569, the absence 

 of the yellow sodium being explained by the half-and-half absorption 

 and radiation mentioned in the discussion of the causes which mask 

 and prevent the appearance of the lines in a spectrum. 



The line at 636 is in the red just at the end of the continuous 

 spectrum, and as yet no origin has been found for it, although it has 

 been observed as a bright line in the Limerick meteorite at the 

 temperature of the o.xxhydrogen blowpipe. 



This star therefore gives a continuous spectrum due to radiation 

 from meteorites, and on this we get bright carbon (with one carbon 

 band appearing separate as being beyond the continuous spectrum 

 in the blue), with bright lines of iron, manganese, sodium, and 

 some as yet undetermined substance giving a line at 636 in the oxy- 

 hydrogen blowpipe. 



Wolf and Rayet's results are given in the { Comptes Rendus,' 

 vol. 65, p. 292. 



Dr. Vogel's are from the 1 Publicationen des Astrophysikalischen 

 Observatoriums zu Potsdam,' vol. 4, Xo. 14, p. 19. 



3rd Cygnus. — B.D. -f 36°, No. 3956. — This is one of the three stars 

 observed by Messrs. Wolf and Rayet, in 1867, as having bright lines 

 in their spectra, but they do not give measurements of the wave- 

 lengths of the lines. They give, however, lines at 581, 573, 540, and 

 470, as present in 2nd Cygnus, so we can reasonably infer these wave- 



