Chap. 10.] Mock Suns. 287 



Jarge white circle, parallel to the horizon, which pafTes 

 through all the parhelia ; and, if it was entire, would 

 go through the center of the fun; fometimes there are 

 arches of fmaller circles concentric to this, and touch- 

 ing the coloured circles which furround the fun ; they 

 are alfo tinged with colours, and contain other par- 

 helia. 



One of the molt remarkable appearances of this kind 

 was that which was obferved at Rome by^Scheiner, as 

 intimated above, and this may ferve as a fufficient in- 

 fiance of the parhelion. 



This celebrated phenomenon is reprefented in Plate 

 XXV. Fig. 56. in which A is the place of the' ob- 

 ferver, B his zenith, C the true fun, A B a plane paf- 

 fing through the obferver's eye, the true fun, and the 

 zenith. About the fun C, there appeared two concen- 

 tric rings, not compleat, but diverfified with colours. 

 The leffer of them, D E F, was fuller, and more per- 

 fect ; and though it was open from D to F, yet thofe 

 ends were perpetually endeavouring to unite, and fome- 

 times they did fo. The outer of thefe rings was much 

 fainter, fo as fcarcely to be difcernible. It had, how- 

 ever, a variety of colours, but was very inconltant. 

 The third circle, KLMN, was very large, and en- 

 tirely white, pafTing through the middle of the fun, and 

 every where parallel to the horizon. At firll this circle 

 was entire ; but towards the end of the phenomenon 

 it was weak and ragged, fo as hardly to be perceived 

 from M towards N.. 



In the interfeclion of this circle, and the outward iris 

 G K I, there broke out two parhelia, or mock funs, 

 N and K, not quite perfect, K being rather weak, but 

 N ihone brighter and ftronger. The brightnefs of the 

 jniddle of them was fomething like that of the fun, but 



towards 



