THE NEW STAR WHICH FADED INTO STAR-MIST. 129 



is monochromatic, and after passing through the prisms 

 remains concentrated in a bright line." A more careful 

 examination showed that not far from the bright line was 

 a much fainter line; and beyond this, again, a third ex- 

 ceedingly faint line was seen. The brightest of the three 

 lines was a line of nitrogen corresponding in position with 

 the brightest of the lines in the spectrum of our own air. 

 The faintest corresponded in position with a line of hydrogen. 

 The other has not yet been associated with a known line 

 of any element Besides the faint lines, Dr. Huggins per- 

 ceived an exceedingly faint continuous spectrum on both 

 sides of the group of bright lines; he suspected, however, 

 that this faint spectrum was not continuous, but crossed by 

 dark spaces. Later observations on other nebulae induced 

 him to regard this faint continuous spectrum as due to the 

 solid or liquid matter of the nucleus, and as quite distinct 

 from the bright lines into which nearly the whole of the 

 light from the nebula is concentrated. The fainter parts of 

 the spectrum of the gaseous nebulae, in fact, correspond to 

 those parts of the spectrum of the " new star " in Cygnus 

 which last remained visible, before the light assumed its 

 present monochromatic colour. 



Now let us consider the significance of the evidence 

 afforded by this discovery not perhaps hoping at once 

 to perceive the full meaning of the discovery, but endea- 

 vouring to advance as far as we safely can in the direction 

 in which it seems to point 



We have, then, these broad facts : where no star had 

 been known, an object has for a while shone with stellar 

 lustre, in this sense, that its light gave a rainbow-tinted 

 spectrum not unlike that which is given by a certain 

 order of stars; this object has gradually parted with its 

 new lustre, and in so doing the character of its spectrum 

 has slowly altered, the continuous portion becoming fainter, 

 and the chief lustre of the bright-line portion shifting from 

 the hydrogen lines to a line which, there is every reason to 

 believe, is absolutely identical with the nebula nitrogen line : 



K 



