Feb, 16, 1882] NATURE 309 
and the belt showing a tendency to divide into parallel | The rays which sometimes, but rarely, appeared during 
bands, whilst its brilliancy remained the same towards | the arc-aurora also confirms the supposition. They were 
the lower and upper edges; Nordenskjéld considers | usually cast from the interior arc towards the exterior and 
therefore as most probable that all the luminous sheet | reached its edge, but never went beyond it. On the con- 
afforded by these arcs was in the same plane. trary, when the aurora was intense, new rays were cast 
Fic. 3.—-Aurora at the /’egu’s winter-quarters, March 3, 1879. at g p.m. 
Fic. 5.—Elliptic aurora seen on March 21, 1879, at 2 15 a.m. 
Fic. 6.—The same, at 3 a.m, 
from the exterior arc, as well towards the interior one, as are in the same plane which passes through. both lumi- 
in the upper space. These phenomena render it most nous circles. If these two circles were situated. in the 
probable that these rays (which must not be confounded | same upper strata of our atmosphere, it would be-reason- 
with those which form the draperies during strong aurore) able to suppose that the rays which flow from one to 
