THE NEW STAR WHICH FADED INTO STAR-MIST. 125 



a simultaneous process of combustion. If this process is of 

 short duration, then the continuous spectrum, as was the 

 case with the new star of 1876, will very quickly decrease in 

 intensity down to a certain limit, while the bright lines in the 

 spectrum, which result from the incandescent gases that 

 have emanated in enormous quantities from the interior, will 

 continue for some time." 



It thus appears that Herr Vogel regarded the observa- 

 tions which had been made on this remarkable star up to 

 March 10 as indicating that first there had been an outburst 

 of glowing gaseous matter from the interior, producing the 

 part of the light which gave the bright lines indicative of 

 gaseity, and that then there had followed, as a consequence, 

 the combustion of a portion of the solid and relatively cool 

 crust, causing the continuous part of the spectrum. We 

 may compare what had taken place, on this hypothesis, with 

 the outburst of intensely hot gases from the ulterior of a 

 volcanic crater, and the incandescence of the lips of the 

 crater in consequence of the intense heat of the out-rushing 

 gases. Any one viewing such a crater from a distance, with 

 a spectroscope, would see the bright lines belonging to the 

 out-rushing gases superposed upon the continuous spectrum 

 due to the crater's burning lips. Vogel further supposes 

 that the burning parts of the star soon cooled, the majority 

 of the remaining light (or at any rate the part of the re- 

 maining light spectroscopically most effective) being that 

 which came from the glowing gases which had emanated in 

 vast quantities from the star's interior. 



" The observations of the spectrum show, beyond doubt," 

 he says, "that the decrease in the light of the star corre- 

 sponds with the cooling of its surface. The violet and blue 

 parts decreased more rapidly in intensity than the other 

 parts ; and the absorption-bands which crossed the spectrum 

 have gradually become darker and darker." 



The reasoning, however, if not altogether unsatisfactory, 

 is by no means so conclusive as Herr Vogel appears to think. 

 It is not clear how the incandescent portion of the surface 



