But, as everybody knows, it is in the Arctic regions that the Aurora,
or the ``Northern Lights,'' can best be seen. There, in the long polar
night, when for months together the sun does not rise, the strange
coruscations in the sky often afford a kind of spectral daylight in
unison with the weird scenery of the world of ice. The pages in the
narratives of Arctic exploration that are devoted to descriptions of
the wonderful effects of the Northern Lights are second to none that
man has ever penned in their fascination. The lights, as I have
already intimated, display astonishing colors, particularly shades of
red and green, as they flit from place to place in the sky. The
discovery that the magnetic needle is affected by the Aurora,
quivering and darting about in a state of extraordinary excitement
when the lights are playing in the sky, only added to the mystery of
the phenomenon until its electro-magnetic nature had been established.
This became evident as soon as it was known that the focus of the
displays was the magnetic pole; and when the far South was visited the
Aurora Australis was found, having its center at the South Magnetic
Pole. Then, if not before, it was clear that the earth was a great
globular magnet, having its poles of opposite magnetism, and that the
auroral lights, whatever their precise cause might be, were
manifestations of the magnetic activity of our planet. After the
invention of magnetic telegraphy it was found that whenever a great
Aurora occurred the telegraph lines were interrupted in their
operation, and the ocean cables ceased to work. Such a phenomenon is
called a ``magnetic storm.''

The interest excited by the Aurora in scientific circles was greatly
stimulated when, in the last half of the nineteenth century, it was
discovered that it is a phenomenon intimately associated with
disturbances on the sun. The ancient ``Zurich Chronicles,'' extending