August 13, 1885 | 
is furrowed transversely by waves of energy following in 
rapid succession, under the influence of which the 
streamers momentarily flare up. If this be the case, or 
the streamers really move, it is impossible to tell. 
“ The longitudinal course of the streamers is not appa- 
rently only, but in reality, very nearly vertical, as several 
facts prove that they point in the same direction as the 
magnetic inclination needle.” . . . “In regions near the 
magnetic pole, where the magnetic inclination is greater, 
the streamers stand more perpendicularly than in more 
southern latitudes, where they form a smaller angle with 
the surface of the earth. 
“Some students, as, for instance, Baron Nordenskjéld, 
have advanced the theory that the streamers do not 
occupy this position, but lie more parallel with the earth ; 
NATURE 
352 
and, indeed, when observing an apparently perpendicular 
streamer in the north, it may in reality form any angle 
with the horizon, and still seem to the eye to stand per- 
pendicular. But from various circumstances it is clear 
that the direction of the streamers is, as I have stated 
above—viz. parallel with the inclination needle. This is, 
in fact, demonstrated not only by the streamers high in 
the sky, which form the upper part of the corona, but also 
by those which, under intense auroree, stand either in the 
east or west, and which are then seen ‘from the side, so 
to speak, z.e. they stand very nearly perpendicularly, as 
indicated to all appearances by the streamers seen to the 
north ‘ 27 front.” 
The auroral covova, the grandest sight of all, is found 
at the instant a band or broken band forming a colonnade 
of streamers reaches the magnetic zenith in its progress 
from the north :— 
“Quick as lightning streamers break forth at the same 
moment on the southern side of the magnetic zenith, 
and as the aurora travels further and further southwards, | 
the corona becomes more and more complete. In northern 
regions, where the aurora frequently appears high in the 
sky, in a northerly or southerly direction, there is often 
an opportunity of seeing this form of the phenomenon, 
when a band of streamers passes the magnetic zenith in 
its course north or southwards. It is, however, not 
always that the aurora’s passing of the zenith has the 
effect of producing the corona; it is seldom the case 
when a band constituted of diffuse luminous matter 
passes this point. It is, in fact, the streamers which 
create the corona.” ... 
B 
Fic. 9.—Cororas (Koutokzino). 
“Tf it be borne in mind that the course ot the auroral 
streamers is identical with that of the magnetic inclina- 
tion needle, it is easy to perceive the origin of the 
ordinary radiating aurora as well as the corona.” . . . 
“This form of the Aurora Borealis, which generally 
indicates, at all events in southern latitudes, the culmina- 
tion of the aurora as regards splendour, colour, and deve- 
lopment, is produced by the streamers shooting from 
every part of the sky towards a common point—viz. the 
magnetic zenith. With this point as centre they seem to 
radiate in every direction ; some are very long, others 
short, while some form rays or bands one above the other. 
The heaven thereby assumes the appearance of a huge 
cupola, or tent of fire. In reality the streamers are all 
parallel ; their appearance of radiating in all directions 
from a central point with various angles being due to 
