1888.] of the various Species of Heavenly Bodies. 



43 



lengths are fairly correct for this star, especially as Dr. Vogel's 

 measurements of the bright lines are 582 and 569 with a bright band 

 commencing at 468. Vogel, in addition to his wave-lengths, also 

 gives a sketch of the spectrum in which he shows the bright 540 line; 

 and a light curve showing the variations of the intensity of the light 

 throughout the spectrum, in which curve he indicates all the lines 

 above-mentioned, and an additional bright line at 636. 



The sketch shows also a dark band in the spectrum from about 

 488 to 473, another from 553 to 556, and a third on the blue side of 

 570 extending from that line to 564. These dark spaces are confirmed 

 in the light curve, and two of them, 488 to 473, and 570 to 564, agree 

 with the dark spaces observed by Messrs. Wolf and Rayet in 2nd 

 Cygnus. 



The bright band at 470 is the carbon band in the blue commencing 

 at 474, with its maximum at about 468, as observed and photographed 

 at Kensington, and between this and 488 is the dark space which is 

 most probably due to absence of radiation rather than to any 

 absorption. The carbon at 517 asserts itself by a rise in the light 

 curve at that point, while the 564 carbon is also seen to produce a 

 sudden rise in the curve. 



The 564 carbon and the 558 manganese fluting uniting produce 

 a bright band of light between those wave-lengths, and this 

 on the faint continuous spectrum produces an apparent dark 

 space on each side, thus accounting for the dark appearances 

 at 554 — 557 and 564 — 570, these being contrast appearances 

 only and not absorption bands. The 540 line is the manganese 

 line seen in the bunsen burner. The line at 570 is most pro- 

 bably the green sodium line, the yellow sodium being rendered 

 invisible by the half-and-half absorption and radiation masking pre- 

 viously mentioned. The 580 line is most probably the strongest low- 

 temperature line of iron, 579 ; while the 636 line has been seen in the 

 Limerick meteorite when heated in the oxyhydrogen flame, although 

 its origin has not yet been determined. 



In this star, therefore, we have continuous spectrum from the 

 meteorites ; carbon bands at 474, 517, and 564, rendering them- 

 selves apparent in the light curve ; the low-temperature manganese 

 line and the strongest manganese fluting ; the low-temperature iron 

 line, the green sodium, and a line the origin of which is unknown, 

 all appearing bright. There is no absorption. 



Vogel's results are given in the £ Publicationen des Astrophysikal- 

 ischen Observatoriums zu Potsdam,' vol. 4, No. 14, p. 19. 



7 Cassiojpeice. — Secchi at the very commencement of his work at 

 stellar spectra noticed the bright lines in the spectrum of this star. 

 He records the presence of bright lines of hydrogen and of the bright 



