59 
VII. 
THE AURORA. 
By Proressor ARTHUR Scuuster, F.R.S. 
For an account of the general appearance of the aurora we cannot do 
better than transcribe Lieutenant Weyprecht’s description (Payer’s 
‘New Lands within the Arctic Circle’), as quoted in Mr. Rand 
Capron’s book on the Aurora. 
“There in the south, low on the horizon, stands a faint arch of 
light. It looks as it were the upper limit of a dark segment of a 
circle; but the stars, which shine through it in undiminished bril- 
liancy, convince us that the darkness of the segment is a delusion 
produced by contrast. Gradually the arch of light grows in intensity 
and rises to the zenith. It is perfectly regular; its two ends almost 
touch the horizon, and advance to the east and west in proportion as 
the arch rises. No beams are to be discovered in it, but the whole 
consists of an almost uniform light of a delicious tender colour. It 
is transparent white with a shade of light green, not unlike the pale 
green of a young plant which germinates in the dark. The light of 
the moon appears yellow contrasted with this tender colour, so pleas- 
ing to the eye and so indescribable in words, a colour which nature 
appears to have given only to the Polar Regions by way of compensa- 
tion. The arch is broad, thrice the breadth, perhaps, of the rainbow, 
and its distinctly marked edges are strongly defined on the profound 
darkness of the Arctic heavens. The stars shine through it with 
undiminished brilliancy. The arch mounts higher and higher. An 
air of repose seems spread over the whole phenomenon; here and 
there only a wave of light rolls slowly from one side to the other. It 
begins to grow clear over the ice; some of its groups are discernible. 
The arch is still distant from the zenith, a second detaches itself from 
the dark segment, and this is gradually succeeded by others. All 
now rise towards the zenith; the first passes beyond it, then sinks 
slowly towards the Northern horizon, and as it sinks loses its inten- 
sity. Arches of light are now stretched over the whole heavens; 
