Feb, 22, 1883] 
NATURE 
395 
complying with this request arises from the fact that I 
had this winter changed my residence from Bergen, 
where the communication was directed, to this spot— 
Kautokeino, in Ultima Thule. 
Since September -last I have, for the sake of the 
aurora borealis, been residing here in North Finmarken 
(69° N. lat., 23° E. long ), in a quarter, therefore, where the 
auroree attain their maxima, and where the phenomena, 
consequently, are so frequent and on such a scale that 
there cannot be 2 question of selecting and analysing one 
in particular. I therefore prefer to give briefly a descrip- 
tion of its general appearance here, its character and 
occurrence. 
My winter sojourn here has two objects in view—viz. 
firstly, to frame a pendant to the observations of the 
aurorze made at Bossekop, 1838-39, by the French Com- 
mission du Nord (‘Voyages en Scandinavie,” &c.), 
which, by the bye, later students of the phenomenon seem 
to have entirely ignored ; and secondly, by means of alti- 
tudinal measurements corresponding with those now 
being made at the Norwegian Meteorological Station at 
Bossekop, to procure sufficient materials for fixing the 
parallax of the aurora borealis. I choose the remote 
Kautokeino for my observatory for several reasons—viz. 
that this place is situated almost exactly south of 
Bossekop, while the distance between the two places is 
very nearly a degree, a distance which is exactly suited 
to the opinion I have formed as to the height of the 
aurora, viz. 150 kilometres, and also for the reason that 
Kautokeino possesses a very free horizon, and that its 
situation, very far inland, would insure favourable weather 
conditions. 
As previously stated, observations are made simul- 
taneously here and at Bossekop on a common pre- 
arranged plan, and measurements made in the common 
vertical plane by the so-called auroral theodolite, con- 
structed by Prof. Mobn. A similar arrangement has also 
been effected with the Finnish Meteorological Station at 
Sodankyla, which is, however, situated at a great distance 
from this place and in a somewhat unfavourable direc- 
tion (about 45° S.E.). We shall not, of course, be able 
to compare notes before the spring, so I am unable at 
present to lay before the reader the final results ; but 
Judging from my own researches here, I feel convinced, 
in spite of assertions made by scientists to the contrary, 
that the exact height of the aurora may be ascertained 
by the method I advocate, and that from the observations 
made at these three stations we shail glean sufficient 
materials to solve a problem hitherto deemed an insoluble 
one. 
Aurore occur here, I may say without exaggeration, 
every night, and an evening without them would be a 
phenomenon as remarkable as their appearance under the 
equator. Unfortunately, however, unfavourable weather 
has during the last two months, accompanied by cloud 
masses unusual in these latitudes, sadly interfered with 
the number and completeness of my observations. Still, 
the magnitude of the aurorz is not the same every night. 
Sometimes they appear as short, faint, arc-shaped pheno- 
mena, similar to those so frequently seen in South Norway, 
while at others they assume an extent and grandeur which 
mocks every attempt at description. 
In one respect my researches here have been of great 
moment to me, ze. with regard to understanding the 
various types of the aurore, their real strike and shape, 
and their exterior appearance, which changes in the dif- 
ferent altitudes above the horizon ; while on account of 
their frequency, and the circumstance that they now 
appear in the north, then in the south, and at last in 
zenith, there is a splendid opportunity to study the modi- 
fications which one particular form of aurora is subjected 
to when changing its position to the observer. It appears 
now conclusive to me that the many forms usually de- 
scribed in researches may be reduced to a few, almost 
similar, types. In most instances the aurora runs in 
zones, belts, in the direction of the magnetic east-west, 
and either as a more or less diffuse luminosity, or as thin 
shining bands, which I have found to be parallel with the 
indication of the inclination needle. But the appearance 
which the phenomenon assumes is entirely dependent on 
the relative position which the observer occupies to the 
same. If he is thus greatly distanced from the aurora 
he will only observe, a few degrees above the horizon, a 
continuous arc with streamers, but if he approaches 
nearer, he will notice several such arcs with clearly 
defined constituents and a greater vibratory motion, 
and if still closer, he will see the “ belts’’ or bands men- 
tioned by Weyprecht far above the horizon; and if these 
then travel towards /zs zenith, he will distinctly see the 
auroral “ corona.” I have just stated that the main strike of 
the aurorze is magnetic east-west; this is, however, only 
stated as a general rule, particularly with those of the 
luminous or “ glory’? type, while the “ belts’’ may, besides 
their slight folds, be twisted and slung in almost any 
direction. I have thus seen them stretch from north to 
south, and even form a continuous circle, which, with 
zenith as centrum, has engirdled the entire heavens at an 
elevation of about 30°. The variable position of these 
luminous belts is the cause of the many peculiarities and 
the deviations from the normal which are so frequently 
observed with the arcs, as, for instance, their unsymmetri- 
cal position in relation to the magnetic meridian, and their 
uneven shape, viz. that they are often bent ecliptically 
back at the points, or even take the appearance of regular 
eclipses. I ought, however, to point out that the faint 
retrograding bend which great arcs assume near the 
horizon is due simply to optical causes. The study of 
the auroral corona here is very instructive. When a belt 
of streamers travels towards the <nagnetic zenith, the 
radiations seem to become shorter and shorter, caused 
by the circumstance that they are seen obliquely, and 
when the belt passes the magnetic zenith, its lower rim 
only is seen, which makes it appear as a bent and folded 
luminous belt. In this position one may observe that 
every individual streamer has only a very limited depth, 
but that the belt consists of several, sometimes of a great 
number, of luminous ‘‘sheets” in a parallel position to 
one another. 
Besides this form of aurora, which thus embraces two 
kinds, viz. the continuous and the radiating, I know only 
one more of a character distinctly differing from the 
same. I do not thus consider the individual knots of ray- 
aurore, or the streamers, as anything but incomplete 
belts ; while the luminous gatherings I consider are 
merely remnants, so to say, of previously radiant aurore. 
I may also here state that the large purple auroral clouds 
peculiar to this phenomenon, when observed during con- 
siderable electrical disturbances in southern climes, 
have never seen at Kautokeino. 
Of quite-a different nature is, however, the phenomenon 
which I have named “coruscation.” This phase of the 
aurora, which almost without exception belongs to the 
earliest hours of the morning, and after large and ex- 
tended oscillations of the aurora, is developed, I believe, 
by the luminous clouds. But while these remain quiet, 
or show at least subdued oscillations, the “ coruscation,” 
as I term it, is so violent and of such a peculiar nature, 
that I have not even yet succeeded in ascertaining 
whether the motion is horizontal or vertical, or whether it 
is the luminous clouds themselves which flood the heavens, 
or their merely momentary “ blazing up’’ under the influ- 
ence of some passing waves of energy. The entire 
heaven is sometimes for hours a bath of liquid fire by 
this force, which seems, by the bye, to possess the same 
remarkable rapidity around zenith as at lower elevations. 
As regard the colours of the aurora, I have only noticed, 
when the substance of light is great, and when the oscil- 
lations are very rapid, two well-known forms, viz. green 
