THE NEBULA OF ORION. 265 



Mr. Lassell's drawing (Fig. 6) exhibits the same characteristics as 

 Herschel's in one respect. He has noted some very faint stars, par- 

 ticularly one, of which we will speak further, but he has omitted others 

 much brighter (at least, brighter in 1874, and also brighter when 

 mapped by Bond in 1865). We must attribute this to a desire to de- 

 pict the form of the nebula itself, and a neglect of the stars in com- 

 parison ; and yet this is difficult to do, since Lassell has given us a 

 map of new stars which he found, some of which have never been seen 

 by any observer since, and presumably do not exist, or have van- 

 ished. Lassell, again, finds no trace of resolvability in this nebula. 



N 

 Nebula Orionis. (Lassell, 1852.) 



It will be noticed that Lassell has a large number of small stars 

 above and to the left of the trapezium. These are put in the map by 

 eye-estimates of their position, and it is somewhat difficult to identify 

 them with Bond's stars in this place, but I have no doubt that all of 

 them are real. Lassell's h and g have never been seen by any later 

 observer, and probably they do not exist, a' of Lassell's map was 

 not even noted by him as a new discovery, but it remained unseen 

 even by the keen vision of Bond and Struve, until the mounting of 

 the great Alvan Clark refractor (18| inches aperture) in 1862, when 

 Alvan Clark, Jr., found this star by the aid of that instrument. 



His observation has been verified by the great Clark refractor, at 

 Washington (26 inches aperture). 



In 1848, Mr. W. C. Bond, Director of Harvard College Observa- 

 tory, made, by the aid of the 15-inch refractor, a map and a drawing 



