The Weekly Kansas chief. [volume] (Troy, Kan.) 1872-1918, 1882-08-24
NoRDEnsKJoID ON THE AURORA.

The general opinion of scientific men in regard
to the aurora boreals, of which we had a brief
though brilliant exhibition last evening, is in
general the one that was first put forth by DIR.
HALEY over a century aud half ago, that il is
Of magnetic or electrical origin. Still the OBJ
servafions of DIR. Nordenskjold during the yoy-
age of the Vega, have thrown new light on the
subject. The term aurora borealis is too excln-
sive, since there is also an aurora australis
which was observed by the Swedish expedition
in ls7273, Mt Muss-l Bay. II usually begaa in
the shape Of an arched band of light at a small
height above the southern horizon. whence as it
rose higher IL became less regular and more
brilliant and divided into bundles of light.
which had a tendency to meet together in the
zenith of the inclination needle. The beams of
light continually changed their places, increas-
ing in number and size. and finally there ap-
peared what is called the beautiful 'draperiess
If rays Sometimes the aurora consisted simply
Of luminous, halo-like arc, quiet aud not brill
liant With only one exception this latter was
the form seen during the Vega expedition. Dr.
Nordenskjold's conclusion from the whole of the
phenomena which he studied was that the earth,
even during year when auroras are very infre-
quent, is adorned with an almost constant
crown of light-single, double or multiple
whose inner edge is usually at . height of about
three one-hundre,lths of the earth's radius
above the surface of the globe, whose surface is
somewhat under the earth's surface, little
north Of the magnetic pole, and which, with n
diameter Of about thirty-two one-hundreths of
the earth's radius extending in plane pcrlrn
dicnlar to the earth's radius, which passes
through the centre of this luminous ring The
double luminous crown is nanied, 10y Nordens-
kjold, the 'aurora glory and of the two rings
Of which it is composed, the interior one. or the
common arc" is the most regular, and il is al
most permanent. IL is, however, visible only
far to the North, which is not commonly inhab-
tied by the people of European origin, aud this
circumstance, together with its feeble brillian-
cy is the cause Of its not having hitber received
much attention. As tn the ray-Guroras visible
in more southern regions, they are but Partic-
ular form of the aurora considered as 4 whole,
and are only emissions of rays from the crowns
of light or aurora slories that surrounded the
polar regions. Various circumstances led Nor
denskiold to conclude that the aurora glory
does not coincide with the magnetic pole, but is
situated ut about Il degrees north latitude and
20 degrees east longitude. and TO this pole, in
order to avoid mistakes, he gives the name of
"Auroral Pole" The SUBMITS of the common
aurora arc being visible in the direction Of the
magnetic north when seen from places situated
beyond the projection of the glory on the earth's
surface, aud in the magnetic south for the OBJ
servers situated within this projection, it is
most probable that the centre of the glory is
within the ellipse which circumscribes that part
of the Arctic regions where the inclination is 80
degrees. But a glance on a map representing
the magnetic meridians shows that this hypOth-
ess is far better satisfied when admitting that
the aurora pole is situated ut the above mention
ed place than if we admit that it comedies with
the magnetic pole. The sections of the great
circles tangential to the magnetic meridians at
a distance of twenty to thirty degrees from the
magnetic pole, meet the surface of the earth
about this same place. But il should be remem-
bercd that the section of the luminous crown, as
also the position of its centre, undergo certain
changes. Under ordinary circumstances these
changes are slow and within certain narrow
limits; but during aurora storms they are both
rapid and wide. In these eases luminous ares
having different centres may appear at once. 1t
is probable that it would not be difficult to de-
tsrmine. From observations made ut two dis
tant places, the laws of these changes; but with
the measurements we have now at our disposalit
is impossible.
The above Describes the interior arc. The sec
ond is nearly parallel to it, and separated from
it by an unlighted space which is sometimes
crowned by rays of light.
1t is most important to determine where, and
under what aspect, the aurora-glOry is visible in
different parts of our globe, and NordenskiOld
gives special attention to the subject. The sec
Ond (outer) ring and its rays can be seen over a
very great surface of the Northern Hemisphere.
If the rays which were seen from the Vega as
flowing from this ring to the zenith were east in
the plane of the glory, and if they were east
from all parts of the ring, they must have been
seen over a circle drawn from the aurora pole by
n radius measuring 5000 kilometres ON the sur
face of the earth. This circle would include
North America as far as California, England,
France, and the northern parts of the lberian
Peninsula, Austri-Hungary, Crimea, Siberia,
and Northern Sakhalin. But the rays often
passed beyond the zenith of the Vega, and thus
the region of their visibility mnst lie still fur
ther increased. including Mexico, Spain, Moroc-
co. Greece, Asia Minor, part of Turkestan, aud
Mantchuria; that is, even such tracts where
auroras very rarely occur. But NOrdenskiold
does not maintain that all anroras observed in
Europe were due to rays east from the glory in
its plane. He thinks it would he too bold an
assertion. it would mean that thousands of
observers in error rs to the idea they got of
the direction of rays But it is probable that
certain part of radent anroras observed in
Europe are due to rays cast in the plane of the
glory, aud not tn rays east in the direction ofthe
inclination needle. As TO the drapery aurora,
which once during the Vegas winter
ing, il seemed to have its seat NEARER To the
face of the earth. such auroras are obviously
in the same relations 10 the common the
irregular winds and storms of the North are to
the regular trade winds of the South.-Ncr York
Graphic.