ue to the line of vision to be seen, especially as
all the rays to the northward of the observer can contribute nothing to
increase the effect. That it is of the nature of rays very much
diffused, can hardly be doubted; and, therefore, if only of a few miles
in depth, its impressions are too faint to be sensible. By referring to
the record of the weather in the second section of this work, an auroral
display will be found on July 12th, the central vortex having passed a
little to the northward the same evening, and the next day passing south
_descending_. On that occasion the author saw an inclined column, in
profile, due east, and between himself and a line of bluffs and timber,
about eight miles distant; And, he has not any doubt that the mass of
rays began where he stood. As in a shower, every drop, passing through a
conical surface, whose axis passes through the sun and through the eye,
contributes to form the apparently distant rainbow.

The altitude of this meteor has been much exaggerated, especially of
those rings or luminous arches, which are often detached completely from
the luminous bank. On the 24th of May, a bright aurora was visible at
Ottawa, but the author's attention was engrossed by the most brilliant
arch of light he had ever seen. It was all the time south of the zenith,
and had no visible connection with the aurora north. At 9 hours, 59
minutes, 30 seconds mean solar time, Arcturus was in the exact centre of
the band, at which time it was very bright, and full 7d wide. At the
same time, Prof. G.W. Wheeler observed the aurora in Perryville, in the
State of Missouri, only 1d of longitude to the westward, but did not see
the arch.[31] The difference of latitude between the two places being 3d
30', and the weather, as he states, clear and still, there is only one
reason why he did not see the arch: it must have been too _low_, and had
become merged in the bank of light. At the time mentioned, the altitude
of Arcturus was 68d 30', and, as Prof. Wheeler assigns only 10d as the
altitude of the bank, the maximum elevation of the arch, on the
supposition of its composing a part of the bank, was 43 miles. At
Perryville, the bank and streamers had disappeared at 10 o'clock. At
Ottawa, the arch or bow disappeared at 10 h. 5 m., differing only the
fraction of a minute from the time at Perryville; but, the bank was
still visible, but low and faint, the greatest altitude having been over
30d. To show the rapid flu