( H* V 
the Sun, then below the Horizon. L& Its/f£w reach- 
ed fifteen or twenty Degrees above the Horizon : It 
was throughout of a rufty red Colour, at firft pretty 
vivid and ftrong,but the Top part much fainter than 
the Bottom nearer the Horizon. He did not remem- 
ber he ever faw any thing like it, except the white 
Pyramidal Glade, which is now entitled by the Name 
of the Aurora Borealis, that being like it except in 
Colour and Length. Again, on the 20th of March , 
171^, in the Evening, he efpied a very odd Sort of 
Light in the Conftellation of ’Taurus. This Glade of 
Light had the fame Motion that the Heavens had, 
and was much like the Tail of a Comet, but pointed 
at the upper End. This Light, I doubt not, is fuch 
as Dr. Childrey firft obferved in England , and Caf- 
fini and others afterwards in France. 
Mr. Mairan proceeds to give an Account of the 
true Figure, Extent, Situation, &c. of this Light, 
or Atmofphere of the Sun. Its true Figure he judges, 
with Mr. Fatioy to be lenticular, and gives a Pro- 
jection of it upon the Plane of the Sun’s Equator, the 
Eye being fuppofed in the Axis of the Sun produ- 
ced through his South Pole at fuch a Diftance as 
makes the Solar Atmofphere appear under the Angle 
of forty-five Degrees. In it you have a View of the 
Nodes, Poles, Limits, Declination and Extent, paf- 
fing through and beyond the Orbits of Mercury and 
Venus, and in fome Parts beyond the Orbis Mag- 
nus. This laft Article of its Extent he demonftrates 
from feveral Obfervations of the Elongations of the A- 
pex of this Pyramid from the Centre of the Sun. This 
has been found to be fometimes double that of Ve- 
nus, and other times 90 Deg- and once or twice- above 
100 , 
