e* 



A CCOUNT or TWO HALOS, 



proportion to the whole refraelion ; nor can it be thought a 

 fufficient reafon for rejecting one corre6lion propofed, that 

 there may yet remain other fmall errors, to which all methods 

 are equally liable, but which it is not the obje6l of the prefent 

 dilFertation to re6tify. 



IX. 



A)i Account of Two Halos, with Parhelia. Bj/ Sir H. C. 

 Englefield, Ba7-t. F. R. S *. 



Uncommon V>^N the 20th of November, 1802, at two o'clock in the 

 ^los round the afternoon, going out of doors, at Richmond in Surry, I per- 

 ceived the fun, accompanied by uncommon halos and parhelia, 

 The weather was fliowery, and the iky had that peculiar 

 turbid appearance, which is the certain forerunner of heavy 

 and long continued rain. The fun flione with a faint and 

 watery light, was very ill defined, and appeared rather elon- 

 gated in a vertical dire6tion. A very denfe cloud occupied 

 all that quarter of the horizon, and rofe up pretty near to the 

 fun. Very heavy clouds covered the eaflern part of the 

 heavens, extending quite to the north, and were proceeding 

 gradually towards the fouth wefi;. The wind was about eaft. 



The altitude of the fun was 14°. The circle nearefl; the 

 . fun was diftant from him nearly 24-°, and was about a der 

 gree in breadth. It was of a pale yellowifli light, but had 

 po tendency to prifmatic colours. 



On the left hand, it extended below a line drawn through 

 the fun parallel to the horizon. To the right, it terminated 

 in denfe clouds confiderabJy above that line. 



The exterior circle was 48° from the fun, and it might be 

 l|o in breadth, as it was evidently broader than the inner 

 circle. It terminated on either hand at nearly the fame 

 height as the interior one. It was tinged throughout with 

 the prifmatic colours, though only red, green, and blue, were 

 diftindly vifible. The red was neareft the fun. The blue 

 very faint. The brightnefs of this circle was about that of the 

 fecondary rainbow, to a bright common bow. 



* Royal Inftitutien. IL 1< 



In 



