60 THE ANTARCTIC MANUAL. 
seven are apparent at the same time on the sky, though of inferior 
intensity. The lower they sink towards the North the paler they 
grow, till at last they utterly fade away. Often they all return 
over the zenith, and become extinct just as they came. 
“Tt is seldom, however, that an Aurora runs a course 80 ealm and 
so regular. The typical dark segment, which we see in treatises on 
the subject, in most cases does nét exist. A thin bank of clouds lies 
on the horizon. The upper edge is illuminated ; out of it is developed 
a band of light, which expands, increases in intensity of colour, and 
rises to the zenith. The colour is the same as in the areh, but the 
intensity of the colour is stronger. The colours of the band change 
in a never-ceasing play, but place and form remain unaltered. The 
band is broad, and its intense pale green stands out with wonderful 
beauty on the dark background. Now the band is twisted into many 
convolutions, but the innermost folds are still to be seen distinctly 
through the others. Waves of light continually undulate rapidly 
through its whole extent, sometimes from right to left, sometimes 
from left to right. Then, again, it rolls itself up in graceful folds. 
It seems almost as if breezes high in the air played and sported with 
the broad flaming streamers, the ends of which are lost far off on the 
horizon. The light grows in intensity, the waves of light follow each 
other more rapidly, prismatic colours appear on the upper and lower 
edge of the band, the brilliant white of the centre is enclosed between 
narrow stripes of red and green. Out of one band have now grown 
two. The upper continually approaches the zenith, rays begin to 
shoot forth from it towards a point near the zenith to which the 
South Pole of the magnetic needle, freely suspended, points. 
“The band has nearly reached it, and now begins a brilliant play of 
rays lasting for a short time, the central point of which is the magnetic 
Pole—a sign of the intimate connection of the whole phenomenon 
with the magnetic forces of the earth. Round the magnetic Pole 
short rays flash and flare on all sides, prismatic colours are discernible 
on all their edges, longer and shorter rays alternate with each other, 
waves of light roll round it as a centre. What we see is the auroral 
corona, and it is almost always seen when a band passes over the 
magnetic pole. This peculiar phenomenon lasts but a short time. 
The band now lies on the Northern side of the firmament; gradually 
it sinks, and pales as it sinks; it returns again to the South to change 
and play as before. So it goes on for hours: the aurora incessantly 
changes place, form and intensity. It often entirely disappears for 
a short time, only to appear again suddenly, without the observers 
clearly perceiving how it came and where it went; simply, it is there. 
