Effects of Unequal Refraction at Bridlington Quay. 13 



lower. Shortly after mid-day, it appeared so striking from the 

 level of the street, (ten feet below the sitting-room), that it be- 

 gan to attract the notice of all the inhabitants in the neighbour- 

 hood. 



From 2 until 5 p. M., the phenomena were more indistinct, and 

 less interesting ; but as the heat began to abate (towards 6 p. M.), 

 the appearances observed in the morning were in a great mea- 

 sure repeated. 



On several other occasions, the coast of Holderness was seen 

 through unequally refractive media ; but there was no appear- 

 ance so interesting as the one above described. 



No other cause requires to be sought for, in explanation of 

 the phenomena, than that of different parallel strata of air, of un- 

 equal density, so ably demonstrated and illustrated by Dr WOL- 

 LASTON (Phil. Trans, for 1810) ; and so strikingly exemplified 

 by Dr BREWSTER, in his experiments resembling the very effect 

 in nature, with hot and cold strata of water or glass. 



Nor is the striking peculiarity observed on the Holderness 

 Coast, of the phenomena being confined to a particular level in 

 the position of the observer, of difficult explanation. In this 

 case, it is perhaps only necessary to suppose, (I speak doubtful- 

 ly, however), that the distant coast, observed from the upper al- 

 titude, was seen altogether through an upper stratum of air, of 

 pretty uniform density ; and also observed from the lower sta- 

 tion, that it was either seen chiefly through a lower stratum, or 

 through different strata, amid which the rays of light passed from 

 the distant coast converging, but not having arrived at a focus ; 

 but that from the middle altitude, the rays from the land passed 

 so obliquely out of one medium into the other, that a part was 

 refracted back again into the former medium, so as to double the 

 object, by presenting an inverted image. 



The occasion of the frequency of these phenomena, during 

 the last summer, and of their extraordinary character, may, per- 



