108 
REV. JAMES FARQUHARSON ON THE AURORA BOREALIS. 
across the heavens from east to west, about 8° or 10° north of the zenith ; its 
western end resting on a low cloud, and the eastern one descending with a full 
rich light close to the visible horizon. As this was the first time I had seen 
such an elevated arch reach to the horizon, that circumstance, and some others, 
excited my attention particularly. The eastern extremity of the arch was of 
unusual breadth, about 20°, for about the same number of degrees upwards, — 
seeming to falsify the conclusions, which I had derived from former observations, 
regarding the thinness of the fringe of vertical rays. Another arch appeared 
further north, about 40° high, and 20° or 25° broad, composed of streamers all 
directed to a point south of the zenith. This last had the peculiarity of being 
suddenly bent downwards, and narrowed in its western part from a point near 
the magnetic meridian. The horizon near the magnetic meridian was at the 
same time brightly illuminated under the arches. 
A quick progress towards the south became immediately sensible in both 
arches. The highest arch in a few minutes reached the zenith, and appeared 
there much narrower and better defined in its edges ; and when at this height, 
its eastern broad end became resolved into two separate and nearly vertical 
columns of light, the most southerly of which was the continuation of the arch 
itself, and the most northerly a low column of about 20° in height. Each of 
these columns, when in their progress south they attained their narrowest di- 
mensions, was about 5° broad, and the interval which separated them a little 
more. Here then were two vertical fringes of rays, following each other at a 
comparatively short interval ; or what is rendered more probable, from a cir- 
cumstance which will be presently stated regarding the more northerly arch, 
two fringes, preserving parallel planes, and simultaneously moving southward, 
but the one placed both to the north and the east in relation to the other. This 
arch was both broader and more irregular in its edges at the zenith than any I 
had formerly seen, being at least 6° in breadth. Its progress southward was 
very evidently occasioned by the formation of patches, and even very narrow 
parallel zones of light at its southern edge, sometimes considerably beyond its 
line, and the extinction of patches at the northern edge*. Its progress southward 
was very quick, ranging over 40° in about ten minutes. It reached about 30° 
south of the zenith, and then slowly disappeared ; previously to which, how- 
* I have often in other cases seen this peculiar manner of progress. 
