an unusual horizontal Refraction of the Air. 2 1 
Daring the remainder of my stay at Ramsgate, which was 
about five weeks, I continued daily to examine all the ships in 
sight; but I discovered no phsenomena similar to those which 
I have here given a description of. The phaenomenon of the 
ship observed by Mr. Huddart, differed altogether from those 
above described, as the inverted image which he observed was 
below the ship itself. An appearance of this kind I observed 
on August the 17th, about half an hour after three o'clock in 
the afternoon, of which fig. 9. is a representation. The real 
ship is represented by A, and the image by B; er,mv, the hulks; 
s t the flag, and wx its image, just touching it, with the sea xy 
below. Between the two hulks, some faint dark spots and lines 
appeared, but I could not discover what they were the repre- 
sentatives of. The vessel, at the time of this appearance, was 
not quite come up to the horizon ; and, as it approached it, the 
image gradually diminished, and totally disappeared when the 
ship arrived at the horizon. / 
It remains now, that we inquire into the causes which might 
produce the very extraordinary effects which have been above 
related. From the phsenomena, we are immediately led to the 
nature of the path of the rays of light to produce them ; and 
we may conceive, that the air may possibly be in such a state 
as will account for the unusual tract which, they must have de- 
scribed. For, let h z (fig. 10.) be the surface of the sea ; a b an 
object ; E the place of the eye ; ar E, b s E, the progress of two 
rays, by the usual refraction, from the extreme parts of the ob- 
ject to the eye ; to these curves draw the tangents Ea', E b', 
and a' b' will be the image of the object, as uspally formed. 
Now, if we take the case represented in fig. 4, let a" b" repre- 
sent the inverted image, and a'" b"' the erect image ; join a" E, 
