[ 84 ° ] 
20° from th t Zenith : Out of thefe arofe three beau- 
tiful Pyramids of Light, which extended very near 
the Zenith'? the middle of thefe Pyramids were of a 
beautiful Sea-green, which went off gradually in 
lighter Shades towards the Edges, which were of a 
bright White; the Colour of thefe very much refem- 
bled the Light of Rhofphorus. I obferved thefe 
Columns for fomeMinutes, and then, going in a-dcors, 
faw no more of the Phenomenon ; and was told, half 
an Hour after, that it was all over; but have been 
informed fmce, that it returned again about Ten } 
when the Rednefs fpread, almoft univerfally, over the 
Southern Parts of the Heavens. 
XXIV. A Letter from Mr.JohnMartyn, F.R.S. 
Prof. Botan. Cantab, to John Machin, _Efq^ 
Seer. R. S. andV rof. Aftron. Grefham. con- 
cerning an Aurora Auftralis, feen March 1 8 a 
173 8-p. ^Chelfea^ near London. 
SIR, 
I Now trouble you with a rude Account of the 
Aurora Auftralis, or what other Name you chufe 
to call it by, which was mentioned at the Society 
laft Thurftday. 
Sunday , March 18. 17; 8-9. at half an Hour paft 
Eight, being informed, That there was a great Fire 
towards London , I made hafte towards an upper 
Window that looked to the North North-caft : I found 
an extraordinary Rednefs in the Air, but of too de- 
termined 
7 
