8 HISTORY of the SOCIElT: 



•This appearance continued for more than 20 minutes, when 

 it gradually vanifhed, giving place to thin fcattered vapours, 

 which, towards fun-fet, began to overfpread the fky. Through 

 the enfuing night, I could not difcern the fmallefl trace of thefe 

 meteors in the fky. 



This appearance, I find, is not altogether new. In the Annual 

 Regifter for 1789, there is an account, extracted from the Philo- 

 Jophical Tranfaflions, of an aurora borealis feen by day-light in 

 Ireland, by Dr Henry Usher, who, considering himfelf as the 

 nrft obferver of this phenomenon, requefls that any perfon to 

 whom a fimilar appearance may occur would communicate his 

 obfervations. There is indeed reafon to believe, that the phe- 

 nomenon occurs not unfrequently ; but unlefs it is attended to 

 very accurately, it will in general efcape obfervation; nor fhould 



1 have at this time remarked it, had I not been engaged in ob- 

 ferving the folar halo. Whenever the fky, being for the mofl 

 part cloudlefs, is fuffufed with thin pale vapours, efpecially if 

 difpofed in longitudinal ftreaks, obfervers fhould look out for 

 this phenomenon," 



1800. An account of two interfering rainbows, feen at Dunglafs 



Jan. 6. j n £ a ft- Lothian in July laft, was communicated by Profeffor 



I nenomenon ot •» » » 



two intei-fedl- PlAYFAIR. 



nig rainbows. 



" At Dunglafs, where I happened to be in the beginning of 

 July lad, our attention was called one evening, a little before 

 funfet, to a very large and beautiful rainbow, formed on a 

 cloud which hung over the fea, and from which a fhower was 

 falling at a confiderable diftance to the S. E. The fun was about 



2 ° high, fo that the arch was not much lefs than a femicircle, 

 with its higheft point elevated about 40 °. At the point where 

 the northern extremity of this arch touched the horizon, ano- 

 ther arch feemed alfo to fpring from the fea, diverging from 

 the former at an angle of 3° or 4% on the fide toward the fun. 



This 



