THE HORSESHOE NEBULA IN SAGITTARIUS. 271 



the same thing occur among the nebula? ? And if such changes were 

 once established, would not an important increase of our knowledge 

 accrue, concerning these objects of which almost nothing was known ? 

 It was one of the avowed objects of Sir John Herschel's celebrated 

 journey to the Cape of Good Hope to figure the nebulae of the southern 

 sky, and, while there, the drawing given in Fig. 2 was made, although 

 it was not published until 1847. 



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As we have said, Herschel's paper of 1833 created a wide-spread 

 interest among astronomers, and about 1836 two monographic studies 

 of the Horseshoe Nebula were begun, under circumstances so different 

 as to deserve our attention, Lamont, the accomplished director of 

 the Observatory of Munich, and Mason, an undergraduate of Yale 

 College, commenced observations at about the same time : one being 

 supplied with all the appliances which were known to astronomers. 



