101 



genommen. Vom 16. Mai angefangen, nahm das zusammenhängende 

 Spectrum rascher an Helligkeit ab, als das Gasspectrum, so dass am 

 23. Mai, obgleich das Spectrum im Ganzen schon sehr matt („faint") 

 war, die hellen Linien glänzend erschienen im Vergleiche mit dem 

 zusammenhängenden Spectrum. 



Bei der ersten Beobachtung am 16. Mai bemerkten übrigens Hug- 

 gins und Miller einen matten Nebel, welcher sich in geringer Ent- 

 fernung rings um den Stern erstreckte und an der äusseren Grenze 

 stufenweise verschwand. Die sorgfältige Vergleichung mit den benach- 

 barten Sternen ergab, dass diese Erscheinung eines sehr matt leuchten- 

 den Nebels in der That dem Sterne selbst angehörte. Am 17. Mai war 

 dieser Nebel nur noch zu vermuthen; am 19. und 21. Mai war er nicht 

 mehr zu sehen 1 ). 



Descriplion of the G a s eous Spectrum. A bright line much 

 brighter than the pari of the principal spectrum where it occurs, 

 coincides with Frauenhofens I' 1 . Af rather more than one fourih of 

 the distance betteeen JP 1 and (jf a second and less brillant line ums seen. 

 Beyond this line and at less than a third of its distance from F a third 

 bright line still faint er , and either double or nebulous, was abserved. A 

 fourih bright line was seen by glimpses in the more refrangible part of the 

 spectrum. In the red, in the position of Frauen ho fers (Ja bright red 

 band was seen. 



It is well known that CJ and f 1 of the solar spectrum coincide with 

 lines of hydrogen. On the evening of the 17 May I observed the lines of 

 hydrogen healed by the induetion spark in the Instrument simullaneously 

 with the brighl line of this remarkable star. The brighlest line coincided 

 wilh the centre of the indefined hydrogen line in the green. On aecount of 

 the faintness of the stellar spectrum the coincidence of the red band could 

 not be delermined with certainty, but it appeared to agree in position in 

 the spectrum wilh the red line of hydrogen. If hydrogen be really the gas 

 from which the lines of this star emanate , the conditious ünder wich it. 

 has become luminous are probably different from those of terrestrial flam- 

 mes. The line in the star is brillant and well defined af the edges, but the 

 green line of hydrogen is usually mor expanded and less luminous than 

 the slrong red line, urich characterises the spectrum of this gas. The faint 

 line seen by glimpses in the more refrangible part of the spectrum of the 

 star, may correspond icilh the blue line of hydrogen. 

 ') Bezüglich der Farbe des Lichtes dieses Sternes bemerkt Huggins 

 (Astron. Nachr. Nr. 1592): The position of the groups of dark lines 



