[ 3 2 3 
■ / 
111 An Account of feme luminous Arches. In a Letter from 
'Mr. William Hey, F. K. S. to the Rev. Jofeph Prieftley, 
LL . D. F. R. S. 
Read December 14, 1786. 
REV. AND DEAR SIR, Leeds, Dec. 31, 1783. 
B EFORE I deferibe the luminous arches which I have 
fee a fmee the commencement of this year, I (hall give 
vou a fhort account of two, which I faw iome years ago, 
though I made no obfervations upon them which could at all 
illuftrate their origin. 
While 1 was at Buxton, in March 1774* 1 was called out 
bv feme gentlemen, about half pad eight in the morning, to 
fee a luminous arch, which appeared very beautiful in the 
atmofphere. Being then indifpofed, I durlt not flay out of 
doors any confiderable time to examine it, and only made the 
following obfervations refpe&ing it. Its colour was white, 
inclining to yellow; its breadth in the crown apparently equal 
to that of the rainbow. As it approached the horizon, each 
leg of the arch became gradually broader. It was Rational y 
while 1 viewed it, and free from any fenfible corufcations. Its 
direction feemed to be from about the N.E. to the S.W. at 
lead its eaftern leg was inclined to the north, and its weftern 
to the fouth. Its crown, or mod elevated part, was not far 
from the zenith. The evening was clear, and the ftars 
A 
