£ 45 ] 
V. An Account of a luminous Arch. In a Letter from the Rev, 
Mr. B. Hutchinfon to Sir Jofeph Banks, Bart. P. R. S. 
Read December 14, 1 786. 
c T ^ Kimbokorij Feb. 24? 1 7 
L AST night (Monday 23.) at nine o’clock, a very un- 
common aurora borealis appeared here. When I was 
called clown to fee it, it had formed a perfedt, uniform femi- 
circle, of the apparent breadth of half a yard, reaching like 
the rainbow (which it entirely refembled, only that its colour 
was Ample), from the W.S.W. horizon to that of the E.N.E. 
Some of the brighteft ftars of the Bull only juft could be feen 
through it. The whole hemifphere was without a cloud ; 
calm ; b the wind had gone down at weft ; a flight fro ft, after a 
warm thaw, was taking place; and, what was moft extiaordi- 
nary, there was no other aurora boieans in the neaveus till 
this began to fade away, which then, however, arofe a little, 
due N., but without any ftreamers; the ring had no vibratory 
motion. If this phenomenon Ihould have luckily been ob- 
ferved at London or Greenwich, data may be had to determine 
its height from the earth. 
With this view I ran for my quadrant, and found its zenith 
diftance on the meridian fouth 1 1 degrees. Kimbolton is 63 
miles N.N.W. of London, latitude 52 0 ao'. 
I have the honour to be, &c. 
B. HUTCHINSON, 
