observed ahoiU the San an J. Moon. S6l 



tutlng the boiinciarv of a large corona : it is generally of less 

 diameter than iisiisl, and (ifteti coloured with the tints of 

 the his. A beautili'.l one appeared nn the 22d of Decem- 

 ber i 809, about midnight, during the passage of a cirro- 

 stratus before the moon. 



Corona. Def. Discus Ivcidiis, vd portio cirailaris nu' 

 bis reliqua lucidior, in cvjus centro sol out luva videtur. 



Olser. When the sun or moon is seen through a thin 

 cloud, a portion of tlie cloud, more immediately round the 

 sun or moon, appears much lighter than the rest of it: this 

 luminous disk, if I may be allowed the expression, I call a 

 corona. 



Coronas are of various sizes, according to the peculiarities 

 of the refracting vapour: but they seldom exceed 10^ in 

 diameter; thev are lienerally faintly coloured at their edges. 



Frequently, when there is a haio encirchug the moon, 

 there is a small corona more immedialelv round it. Co- 

 ronae, as well as haloncs, have been always observed to pro- 

 gnosticate rain, hail, or snow. As far as I can observe, they 

 arc generally seen m the cirrostratus cloud. 



Corona duplex, Def. Discus lucidus, alium discum 

 paulo lucidiorem ac minorem includcns, in quorum cen- 

 tro commiiTii sol vel luna observatjir. 

 Olser. A double corona is very common; but I never 

 remember to have seen a triple one. 



Parhelion. Def. Imago solis falsa, vel pliires imagines 

 ejusdem generis circa :>olem circtdatim dispositce, et ma- 

 gis mintisvc lialonibiis aliisqne lucidis vittis co-mitatrB. 

 Obser. Parhelia vary considerably in general appearance; 

 sometimes the sun is encircled by a large halo, in the cir- 

 cumference of which the mock suns usually appear: these 

 have ol'tcn small halones round them: they have usually a 

 horizontal band of while light of a pyramidal figure extend- 

 ing from them: sometimes a large semicircular band of 

 light, like an inverted arch, seems to rest upon the halo 

 which encircles the sun : but tliese phsenomena vary too 

 much to be particularly described here: their peculiarities 

 ouiihl to be minutely observed and noted down in a meteo- 

 rological journal. 



Paraselene. Def. Lunce imago falsa, vel plures ima- 

 gines /iitji/s generis circa lunarn dispositce, et magis 

 viiniisve haUnnbus aliisque lucidis vitiis comitatce. 

 Obser. The paraselene, the parhelion, and the several 

 kinds of halo and corona, all appear to be the consequence 

 K 3 of 



