STAR-SYSTEMS. NEBULAE. 



187 



the figure to the left. A similar transformation was effected in the case of the Dumb-bell 

 Nebula. 



CRAB NEBULA. 



Sir John Herschel. 



Lord Rosse. 



DUMB-BELL NEBULA. 



Sir John Herschel. 



Lord Rosse. 



