CHAPTERS ON THE STARS. 



23 



boundary of the preceding end of the main ring. Sweeping around 

 to the north end of the minor axis, it becomes very bright, perhaps by 

 superposition on the broader main ring of the nebula at this place. 

 It crosses this ring obliquely, forming the brightest part of the whole 



Fig. 13. The Triphid Nebula and. its Surroundings, as Photographed 



by Barnard. 



nebula, and then forms the inner boundary of the main ellipse toward 



its following end. The remaining part of the ring is not so easily 



traced, as several other rings interlace on the south end of the ellipse. 



The central star of this nebula has excited some interest. Its light 



