INVERTED IMAGE OP A SHIP. 



139 



image of a ship beneath the image, as shown in 

 Fig. 32; but Dr. Vince, who afterwards observed 

 this phenomenon under a greater variety of forms, 

 found that the ship, which was here considered the 



Fig. 33. 



real one, was only an erect image of the real ship, 

 which was at that time beneath the horizon, and 

 wholly invisible. 



In August, 1798, Dr. Vince observed a great 

 variety of these aerial images of vessels approach- 

 ing the horizon. Sometimes there was seen only 

 one inverted image above the real ship, and this 

 was generally the case when the real ship was full 



