wo. TO, 1882] ~ 
three hours in the south-east. The observations of the 
Swedish expedition at Mussel Bay (Spitzbergen) were but 
very incompletely published, but they were also in accord- 
ance with the present views of Nordenskjoéld. The in- 
terior circle of the bow which was seen from the Vega, 
and which was but 5° above the horizon, must be seen 
from Mussel Bay, close by the zenith, and therefore nearly 
invisible; while the exterior part of the common arc 
appeared as a bow of regularly spread light in the mag- 
netic south. Rays of light were spread from it towards 
the interior circle, and gave rise to the beautiful draperies 
which so often were seen at Mussel Bay. When the 
aurora became still stronger, rays of light were sent out 
even in the interior circle, from the zenith towards the 
magnetic north, and then a crown appeared, whose rays 
seemed to meet together at the place where the inclina- 
tion needle was directed. 
The third regicn (III of the map) is situated between 
two circles drawn from the aurora-pole by radii 16° and 
NATURE 
371 
20° long. In this region the common arc must be in the 
zenith, and, as has already been pointed out, it must be 
less often seen as a bow than as a diffuse light spread 
upon the sky; but this light is so small in comparison 
with the ray-auroree which begin in this region, that it 
must draw but little attention. The second interior circle 
of the glory must appear in this region as a bow in the 
magnetic south, and the common, or the interior one, as a 
luminous arc in the magnetic north, and both arcs must 
cast rays to one another through the zenith, from north to 
south, or wzce versd. The region comprises the northern 
parts of British America, the middle parts of Davis Strait, 
a part of Southern Greenland, Southern Spitzbergen, and 
Franz Joseph Land; Maguire, Tobiessen, and Payer 
wintered in this region. As is known, Weyprecht has 
given avery good 7ésumé of the meteorological observations 
of the expedition, which correspond to a maximum year of 
aurore. There were, during 1872-74, fifty-eight arc- 
aurore, thirteen of which had the summits of their arcs 
Fic. 7.—Map showing the visibility of the common aurora-glory in the northern hemisphere (reduced from Nordenskjild’s map). 
in the magnetic north, and twenty-eight in the south, 
whilst the arcs of seventeen other auroras passed through 
the zenith, or communicated by rays through the zenith 
from north to south, or vice versd. Besides, the aurora 
often began with a diffused light which Weyprecht has 
described as Nordlichtdunst (aurora-mist), and which 
spread over great parts of the sky. Weyprecht draws 
special attention to the arc-aurore, and says: ‘“ Separate 
Yays are not‘seen inthem. The arc has but a moderate 
brilliancy, which is equally distributed throughout its 
surface. Intense aurorze never appear in the shape of 
arcs. The arc characterises the regular and quiet form 
of the phenomenon.’ ! 
The fourth region (IV. of Fig. 7) is a belt drawn by 
two radii 20° and 28° long. It passes through Northern 
Siberia, British America, the southern extremity of 
Greenland, Iceland, Northern Scandinavia, and Novaya 
- * “Die Nordlicht Beobachtungen der Osterr. Ung. Arct. Exped.,” in the 
Deabeebatien der Math.-Wiss. Classe der k. Acad. der Wiss., Wien,” Bd. 
Xxxv., 1878. 
Zemlya. In this region the aurore usually begin with a 
luminous bow in the magnetic north, out of which spread 
radiant beams of more or less intense light, either into 
free space or to another ring parallel to the former, but 
lying higher above the earth’s surface. The observations 
of Wrangel and Anjou, and those of the Vega were made 
in this region, as well as those made in Iceland, Southern 
Greenland, and in the middle parts of British America ; 
but Nordenskjéld did not have these last at his disposal. 
Wrangel has given much attention to auroree and, so far 
as can be judged from the incomplete information pub- 
lished in his ‘Travels’? and in Parrot’s account of 
Wrangel’s physical observations, they confirm the exist- 
ence of a permanent luminous ring around a certain 
point of the earth’s surface, in the neighbourhood of the 
magnetic pole. During his travels on the shore east of 
the Lena mouth, Wrangel mostly saw bow-shaped auroree, 
the summit of which was in the direction N. 12°-22° E. 
(true). 
The fifth region (V. of our map) is inclosed between the 
