The morning star and Catholic messenger. [volume] (New Orleans [La.]) 1868-1881, 1874-02-01
MORNING STAR CATHOLIC MESSENGER SUNDAY FEBRUARY
Tho Aurors Boreahs.

Tho Aurora Boreahs.
From the Catholic world.I
Although many ancient writers allude to
appearances in the sky which, there is NO
doubt, were identical with the aurora, we
have not any very accurate descriptions
the phenomena having been regarded from
superstitious rather than scien tifc point
Of view. The first of these displays of
which we have q careful and scientific
account, is one that occurred A: D: 1860;
but the particulars were not published till
ninety years afterwards, when they ap.
peared in q book called "a Description Of
Meteors." In 1921 the name of Aurora
Borealis was given to this phenomenon, by
Gassendi, the French philosopher, on the
occasion of a remarkable display visible
over great part of Europe. None seem
to have been observed after this till the
year 1907 but during the last century it
mas been by no means uncommon.
1t occurs generally in the spring or
autumn. particularly after dry year. In
the Arctic regions, however, it is the usual
accompaniment of a clear winters night,
and is familiar to the Inhabitants even of
the Shetland Isles. Lights Of a similar
character have been observed towards the
South Pole. Mr.. Forester, in voyage
with Captain Cook, had an opportunity of
observing the Aurora Australis, as it has
been termed, and thus describes it's ap-
pearance: q" 1t consisted of long columns
of clear white light, shooting up from the
horizon to the eastward almost to the
zenith, and gradually spreading over the
whole southern part of the skv. These
columns were sometimes bent sideways at
their upper extremities, and though in
most respects similar to the northern lights
Of our hemisphere, yet differed from them
in being always of q whitish color, whereas
ours assume various tines, especially those
of a fiery and purple hue"
1t is, however, in the no,thern hemis-
phere that there have been most opportuni-
ties of taking minute observations of this
phenomenon, and it is from these that we
are able to form some idea of the natural
operations to which it owes it's existence.
The flashes of light which constitute the
aurora are now generally allowed to be
within the region of the terrestrial atmos
phere though they we're at one time con-
sidered to be far beyond it, as it was
thought that they could not otherwise be
visible at such height from the horizon.
over such an extended area. 1t would
appear, however, that the aurora covers a
larger extent of sky than an observer
except certain arc with its flaming and
streaming off-shoots. It's visibility has,
perhaps, some analogy to that of the rain
bow, which, as is we'll known, appears to
two observers to be of different height,
their positions requiring the light to be re-
nOSOou AAOh OluoIouC p&EGS VI UHo Sky 10
make the angles of incidence and reflection
equal in the case of each. There are
circumstances attending the auroral pheno-
mena which may be accepted as proofs of
their electric nature. 1t is supposed that
the lights seen are flashes of electricity
passing through the higher strata of the at
mospheEe, which are, of course. highly
rarefed; and an experiment whereby
stream of electricity is passed through a
glass tube from which the air has been
exhausted strengthens this view, appear
ances similar to those of the aurora having
been noted.
The position of the arc is observed to
bear remarkable relation to the magnetic
pole; it generally lies east and west, hav-
ing its vertex on the magnetic meridian,
but it appears at all times to have the
magnetic pole for it's centre. The earth
c orrents of electricity, which often inter
fere with the working of electric telegraphs.
are most frequent at the time of display
of the aurora sometimes causing an entire
stoppage in the working of the wires un-
less the electric circuit can, by using double
wires, be rendered independent of the
earth The magnetic compass is also affec-
ted during the display of an aurora, and
often in places where the latter is invisible.
Sir John Franklin, who made some minute
observations in the Arctic regions upon the
of the needle, which are often
30 slight as to require microscopic ex
animation, stated that the motions
were not sudden; but that after an
aurora the needle would travel slowly
in certain direction, aud as slowly
recover its position after several hours. He
also remarked that when the arc was not at
right angles to the magnetic meridian, but
inclined to east or west, the needle deviated
towards that end of the arc which was
D carer to the magnetic pole; after devia-
ton, it would be assisted in recovering it's
position if an aurora occurred in a direction
opposite to the former. He observed that
when the arc seemed to be exactly at right
angles to the meridian, the needle was gen.
orally inclined to the west. The prevalence
of pink, violet. and blue in the colors of the
lights, seems to confirm the probability
that they result from a discharge Of
and the noise affirmed by some
to have been heard at the time of an aurora
display, seems to have resembled some what
the cracking sound heard when sparks
are taken from a Leyden jar, or the con-
dnctor of an electric machine. The hearers
have compared it to the sound made by rub
bling one piece of silk on another and to the
discharge of fire works. Some, however,
including Captains Parry an0 Franklin,
onR