dtjiant Objeiis at Sea. 14 S 



did not at the fame time fee the motion of thefe images,' and that of the fog, yet from memory, 

 I judged the motions to be equal; and they were alfo in the fame diredion. A fog, which by 

 producing an unufual refra£tion, might form thefe images, would, by its motion, produce a 

 correfponding motion of the images. 



I have here defcribed all the different phenomena which I obferved from the unufual rc- 

 fraiSion, of moft of which I faw a great many inflances. Every fhip which I obferved on the 

 other fide of the horizon of the fea, exhibited phenomena of the kind here defcribed, but not in 

 the fame degree. Of ttvofhips, which in different parts were eijually funk below the horizon, 

 the inverted image of one would but juft begin to appear, whilft that of the other would reprefent 

 nearly the whole of the fhip. But this I obferved, in general, that as the fhip gradually defcended 

 below the horizon, more of the image gradually appeared, and it afcended; and the contrary, 

 when the fliips were afcending upon the horizon in different parts, one (hip would have a 

 complete inverted image ; another would have only a partial image ;j and a third would have 

 no image at all. The images were in general extremely well defined, and frequently appeared 

 as clear and fharp as the (hips tbemfelves, and of the fame magnitude. Of the fhips on this 

 fide of the horizon, no phenomena of this kind appeared ; there was no fog upon our coaft, 

 and the fhips in the Downs, and the Soiith Foreland, exhibited no uncommon appearances. 

 The ufual refradion at the fame time was uncommonly great, for the tide was high, and at the 

 very edge of the water I could fee the cliffs at Calais a very confiderable height above the 

 horizon ; whereas they are frequently not to be feen, in clear weather, from the high lands 

 about the place. The French coaft alfo appeared both ways to a much greater diftance than 

 I ever obferved it at any other time, particularly towards the eafl, on which part alfo the 

 unufual refradlion was the flrongefl. 



During the remainder of my flay at Ramfgate, which was about five weeks, I continued 

 daily to examine all the fhips in fight ; but I difcovered no phenomena fimilar to thofe which I 

 have here given a defcription of. The phenomenon of the fhip, obferved by Mr. Huddart, 

 differed altogether from thofe above defcribed, as the inverted image which he obferved was 

 below the fhip itfelf. An appearance of this kind I obferved on Auguft the 17th, about half an 

 hour after three o'clock in the afternoon, of which fig. 9 is a reprefcntation. The real fhip 

 is reprefented by A, and the image by B ; e r, ot v, the hulks ; s t, the flag ; and %v x, its 

 image, juft touching it, with the fea, x ;•, below. Between the two hulks, fome faint dark 

 fpots, and lines appeared, but 1 could not difcover what they were. The reprefentatives of the 

 veffel, at the time of this appearance, was not quite come up to the horizon ; and as it ap- 

 proached it, the image gradually diminifhed, and totally difappeared when the fhip arrived at the 

 horizon. 



It remains now, that we enquire into the caufes which might produce the very extraordi- 

 nary effedts which have been above related. From the phenomena, 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 pofTibly be in fuch a ftate as will account for the unufual trad which they muft have 



defcribed. 



