138 LETTERS ON NATURAL MAGIC. 



the hill behind it must undoubtedly have come to 

 the eye, yet the strength of the image of the 

 castle so far obscured the background, that it made 

 no sensible impression on the observers. Their 

 attention was of course principally directed to the 

 image of the castle ; but if the hill behind had 

 been at all visible, Dr. Vince conceives that it 

 could not have escaped their observation, as they 

 continued to look at it for a considerable time 

 with a good telescope. 



Hitherto our aerial visions have been seen only 

 in their erect and natural positions, either pro- 

 jected against the ground or elevated in the air; 



Fig. 32, 



but cases have occurred in which both erect and 

 inverted images of objects have been seen in 

 the air, sometimes singly, sometimes combined, 

 sometimes when the real object was invisible, and 

 sometimes when a part of it had begun to show 

 itself to the spectator. 



In the year 1793, Mr. Huddart, when residing 

 at Allonby, in Cumberland, perceived the inverted 



