REV. JAMES FARQUHARSON ON THE AURORA BOREALIS. 107 
this arch gradually faded and became extinct, about 10° or 12° southwards of 
the zenith. 
The other arch of this evening was in its general outline parallel to the one 
now described, but much lower in the heavens. It also ended abruptly at its 
western extremity, on a point of the compass much nearer the north than the 
termination of the other. Its vertex was on the magnetic meridian raised 
about 25° or 30° above the horizon ; and its eastern extremity ended at the 
horizon considerably to the eastward of north. In breadth it at first occupied 
a space of probably 15° or 20°; but this could not be correctly estimated, as 
its northern and southern edges were very irregular and variable, owing to the 
incessant shortening and lengthening of the streamers of which it was com- 
posed, which were nearly vertical, and therefore at right angles to the general 
direction and line of the arch. This was its first appearance ; but it gradually 
rose in the heavens, and became much enlarged both in length and breadth, 
increasing the azimuth distance of its extremities from the north, as its vertex 
rose higher in the heavens, but still remaining abruptly broken short at the 
western extremity, and lengthening its vertical streamers till its middle part 
reached an elevation of about 45°. In the mean time, however, the streamers 
near the extremities were gradually changing the angle they made with the 
line of the arch, constantly directing themselves, whatever position the arch 
was in, to a point somewhat south of the zenith. After passing the elevation 
of 45°, the streamers again gradually became shorter at the vertex ; and those 
at the extremities going on at the same time to diminish their angle with the 
line of the arch, the breadth of that became at all points gradually less. This 
order of appearances went on till this arch had attained nearly the first position 
and appearance of the one first described, when it rather suddenly became ex- 
tinct about fifteen minutes after the other had disappeared. 
A luminous space near the north point of the magnetic meridian, appeared 
at this time to promise the formation of a third arch, beginning to show a few 
streamers ; but it soon gradually faded. 
On the evening of the 9th of September, 1827, at 11 o’clock, I witnessed a 
very brilliant, and, with the exception of the one last described, the most in- 
structive aurora borealis which it has fallen to my lot to observe. When first 
seen, a bright arch of light of various width, and jagged at its edges, stretched 
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