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An Account of the Appearance of federal Unufual 
Parhelia 5 or Mock-Suns, together with federal 
Circular Arches lately fee^ in the Air by E: Hallej. 
ON the Eighth of April, this preftnt Year, i yo%, walking 
in London Streets about ten in the Morning, the Air 
being clear, I obferved the Sun to (hine faintly, or as we call 
it, waterifh; whereupon calling up myEye^ I perceived feve- 
ral /irches of Circles abou tt im. I made what haft I could to get 
on the top of a Houft, which I did at Mr. Mordens by the Roy- 
al Exchange^ and found the Appearance as isdefcrib^d in Fi- 
gure 4, 3° wherein 
& is the true Sun, Z the Zenith* 
5 TP Fa great, white Circle paffiog through the Sun, and 
as near as \ could judge, parallel to the Horizon. It was very 
diftind and entire, about two Degrees broad m^^t Northern 
part about/', -and held much the fame breadth in the Eafl and 
Wefl, but grew narrower towards the vSun, its edges were not 
very well defined, the whole appearing hke a faint whiteCloud^ 
and a part of it would have been taken for fuch, but the whole 
Circle (een in the pure Azure Sky was a very furprizing fight. 
V T^X T a Halo, or rather Iris^ that was likewife an inttre 
Circle, having the Sun for its Center. I meafurcd the Semidi- 
ameter of this to be much about %z Degrees: the breath of this 
Arch which was well defined, was by eftimate equal to the 
Suns Diameter, and it was coloured with the Colours of the 
/m, but nothing near io vivid as in the common Rainbow. 
Irhe were next the Sun, and theS/wj in the outward 
Litnb. Within this Circle the Sky appeared fomewhat ob- 
fcure,efpecially near the Arch 5 and 1 take it, that the caufeof 
that 
