C 4<5j ] 
of the primary Iris } he is of Opinion, that the Sun's 
Rays, refratted and reflected as above, entered the 
Eye at half the aforefaid Angle, by the Eye’s being 
placed beyond the Point, where the Rays met with 
the Axis. For thus the Order of the Colours is pre- 
ferved, and this Iris is but half the Size of the 
common one. 
As an Appendix to this Trad, Profeftor Weidler 
adds the following Account of the remarkable red 
Lights on the "^December 1737. feen not only by 
him at Wittemberg . , but here at London , and in mod 
Parts of Europe . 
December 9.1737. the Barometer was remarkably 
lowj 'viz . 28 Inches 8 Lines Engiifh Mcafure. k 
rained all that Day v-ry plentifully $ and from thence 
to the End of the Month the Sky was much loaded 
with thick Vapours. But on the 16th, the little 
Wind there was being atNorth-weft, and the Baro- 
meter at 30 Inches 2 Lines j London Meafure, foon 
after Sun-fet, (the Moon in its laft Quarter) the Sky 
began to appear very red ; and, from Seven to Nine, 
gave a Light as ftrong as that of the Full Moon be- 
hind a thin Cloud. The whole Sky was of that 
Colour, which is occafioned by a Fire feen at a 
Diftance in the Night. Such an uncommon Sight 
put the Inhabitants of this Town in great Tenor. 
The greateft Brightnefs here was about 8 h. 45 ' ; from 
which Time it gradually decreafed ; and at a Quarter 
after Nine it feemed almoft diffipated. But it re- 
turned now-and-then, and continued, by Intervals, 
all Night. Now though the whole Face of the Hea- 
vens was remarkably red, yet the greateft Brightnefs 
was 
