1888.] 



of the various Species of Heavenly Bodies. 



47 



Gothard noticed it; so after all it maybe probable that Konkoly's 

 record of magnesium absorption at b was right, and that in Sherman's 

 observation it was masked by the carbon band. 



Sherman, in £ Astr, Nachr.,' No. 1707, gives a list of fifteen bright 

 Hues in 7 Cassiopeiae, the wave-lengths of which he has determined as 

 accurately as possible. He says, " the difficulties of the observation 

 and the roughness of the recording apparatus have hindered the 

 completely satisfactory identification of the lines. Assuming the 

 position of the hydrogen lines and D 3 , and on their basis constructing 

 a curve connecting scale-reading and wave-length, the mean of nine 

 observations upon 7 Cassiopeiae affords the following approximate 

 wave-lengths." (See map.) 



The line in the yellow being assumed as D 3 at 5875, instead of the 

 5870 manganese, causes an error running all through the measurements, 

 but not sufficient to invalidate any conclusions based on the corrected 

 wave-lengths. 



The hydrogen lines seen are C, F, hydrogen G, and h. We have 

 the manganese at 558 and 586 (D 3 ), as well as the low-temperature 

 line (bunsen) at 540. Iron is represented by lines at 527, 579, and 

 616, these being the strongest low-temperature lines. Magnesium is 

 responsible for the 500 line while the carbon accounts for the 517, 

 thus leaving only the 636 and the 463 lines unaccounted for. 



The line at 636 has been seen in the Limerick meteorite, although 

 its origin has not yet been determined, while the 463 line is bright in 

 R Geminorum, but has up to the present not been detected in any 

 experiment with meteorites. In the spectrum of the first of Wolf 

 and Rayet's stars in Cygnus (B.D. 35°, No. 4001), Yogel has observed 

 the manganese lines at 540 and 558, the iron lines at 527 and 579, 

 and the hydrogen F, all of which are present in 7 Cassiopeiae, the 

 only additional lines seen in 1st Cygnus being the sodium green, 569, 

 and cadmium, 507. 



On the Sequence of Temperature of the §tars in Cygnus. 



The three "bright line stars" in Cygnus, discovered by MM. 

 Wolf and Rayet in 1867, present differences in their spectra, which 

 raise some very interesting questions for discussion. Wolf and Rayet 

 did not observe any great differences in the spectra, simply recording 

 the fact that the second star gave the lines most brilliantly : but 

 Dr. Yogel bas, in his investigations, brought out very striking ones. 



Thus the first of these stars, B.D. + 35°, No. 4001, has seven bright 

 lines in its spectrum, as shown on his light curve, besides the bright 

 band at 468. One of the bright lines is hydrogen F (486). The 

 second, B.D. + 35°, No. 4013, a,nd third, B.D. + 36°, No. 3956, stars 

 have only four bright lines, and the bright band ; the hydrogen (F) 

 line being absent. 



