[ 53S I 
IV. Part of a Letter from Mr Gray, concerning 
an unufual ?2Lxhdion anc/ Halo. 
Canterhury^ May ^th^ l6(^^» 
SIR, 
I Had fcarce thought the account I fent you of the 
Parhelia I obferv*d the 26th of February laft, worth 
your notice, had I not been prompted to think fo by 
the inftigation of my .friends, for I find they are fre- 
quently feen, tho this is the firft I ever faw. But what 
I am now going to relate, is that which fo rarely hap- 
pens, that I cannot think it unworthy your cogni- 
zance. 
April the 7th, 1699. between 4 and 5 of the clock, - 
I firft perceived, and atterwards ftiewed to feveral others 
the following Phsenomena. 
There appeared on each fide the Sun a Parhelion^ 
connefted by an Balo of theufual diameter 5 they had 
each of them a tail of a whitifh colour, extended op- 
pofite to the Sun, of about 15 or 20 degrees in lengthy 
the upper part of the Halo was touched by the arch of 
a Circle, whofe ends were turned towards the Zenith ^ 
t it had the colours of the Iris but faintly, betwixt this 
and the Zenith was another portion of a Circle, which 
had the colours of the Iris with greater vivacity than 
the former 5 the appearance may not be altogether un- 
fitly reprefented by figure 2. where A is to be fuppofed . 
the Sun, B C the Parthelia with their trains, D the co- 
loured arch touching the Halo BD C, E the more vivid 
arch that paft betwixt D and the Zenith Z. 
O o o o 
V. Part 
