MISCELLANEOUS PHENOMENA OF THE POLAR SEAS AND REGIONS--THE AURORA
BOREALIS--ICE-BLINK--OPTICAL ILLUSIONS--ANECDOTE OF SCORESBY--HALOES--
CORONAE--MOCK SUNS--REFRACTION--FROSTS.
Owing to the intensity of the cold in the arctic regions, there are, as
we may readily believe, many singular appearances connected with the
ocean and the atmosphere, which are worthy of special notice.
Chief, perhaps, among the phenomena of those regions is the _Aurora
Borealis_.
Ever mindful of the welfare of the creatures whom he has formed, the
Almighty has appointed a light to mitigate the darkness of the polar
regions when the sun, in its appointed course, withdraws for a season.
What the aurora borealis is no one knows, although many have hazarded
opinions regarding it.
What it is like is known even to ourselves, though the faint indications
of it which sometimes seen in our own heavens are not to be compared to
the brilliancy of the spectacle that is occasionally presented in the
northern skies.
The most ordinary aspect of the aurora is that of a band of pale-green
light extending irregularly over part of the sky, and marked by wavy
motions, as well as by varying brightness. Sometimes one part of this
band becomes more bright than another part. Sometimes the whole seems
to move gently, like the undulations of a flag in a light breeze; at
other times more vigorous action takes place, and pointed tongues of
light shoot vividly up into the zenith. This sometimes takes place so
frequently, and the tongues are so long and numerous, that the aurora
has been popularly termed the "northern streamers."
Although pale-green is the most frequent colour, the aurora borealis has
often been observed with blue and red hues; and the sky has been seen
suffused with an intense crimson colour by it.
Captains Parry and Lyon saw these northern lights in full splendour
during their residence in the arctic regions. They tell us that "the
aurora had a tendency to form an irregular arch, which, in calm weather,
was very often distinct, though its upper boundary was seldom well
defined; but whenever the air was agitated, showers of rays spread in
every direction with the rapidity of lightning, but always appearing to
move to and from a fixed point, somewhat like a ribbon held in the hand
and shaken with an undulatory motion. No rule, however, could be traced
in the movement of those lighter parcels called the `merry dancers,'
which flew about perpetually towards every quarter; becoming in stormy
weather more rapid in their motions, and sharing all the wildness of the
blast. They gave an indescribable air of magic to the whole scene, and
made it not wonderful that, by the untaught Indian, they should be
viewed as `the spirits of his fathers roaming through the land of
souls.'"
We are told by some that the aurora borealis is accompanied by a loud
hissing and crackling sound and Captain Lyon says that the sudden glare
and rapid bursts of those wondrous showers of fire make it difficult to
believe that their movements are wholly without sound. Yet such would
seem to be the case, for the same authority tells us that he stood on
the ice for hours listening intently and could hear nothing. He was
thoroughly convinced that no sound proceeds from the aurora, and most
intelligent voyagers support him in this opinion.
That the aurora dims the lustre of the stars seen through it, is a fact
which was ascertained clearly by the same gentleman; and that it moves
in a region beyond the clouds is also evident from the fact that when
the latter covered the sky the aurora disappeared.
But some of the most singular appearances of the sea and sky in the
polar regions are presented in summer. During that season the perpetual
presence of the sun and the large tracts of ice floating about on the
sea exert their opposing influences so as to produce the most
astonishing results.
One part of the sea being covered with ice, produces a cold atmosphere;
another part being free from ice, produces a warmer atmosphere.
Refraction is the result of viewing objects through those different
media, and very curious appearances follow. When Scoresby was in
Greenland a singular atmospheric phenomenon occurred, whereby he became
aware of the approach of his father's ship some time before it rose
above the horizon. He had reached Greenland before his father, who
followed him in the _Fame_. The following is his account of the
circumstance:
"On my return to the ship, about eleven o'clock, the night was
beautifully fine and the air quite mild. The atmosphere, in consequence
of the warmth, being in a highly refractive state, a great many curious
appearances were presented by the land and icebergs. The most
extraordinary effect of this state of the atmosphere, however, was the
distinct inverted image of a ship in the clear sky, over the middle of
the large bay or inlet, the ship itself being entirely beyond the
horizon. Appearances of this kind I have before noticed, but the
peculiarities of this were the perfection of the image, and the great
distance of the vessel that it represented. It was so extremely well
defined, that, when examined with a telescope, I could distinguish every
sail, the general `rig of the ship,' and its peculiar character;
insomuch that I confidently pronounced it to be my father's ship the
_Fame_, which it afterwards proved to be, though, on comparing notes
with my father, I found that our relative positions at the time gave our
distance from one another very nearly thirty miles, being about
seventeen miles beyond the horizon, and some leagues beyond the line of
direct vision."
Scoresby was, perhaps, one of the most persevering and intelligent
observers of nature that ever went to the polar seas. His various
accounts of what he saw are most interesting. We cannot do better than
quote his remarks upon _ice-blink_, that curious appearance of white
light on the horizon, whereby voyagers are led to infer the presence of
ice:--
"This appearance of the _ice-blink_," says he, "occurred on the 13th of
June 1820, in latitude 76 degrees north. The sky aloft was covered with
dense, uniform, hazy cloud, which indeed occupied the whole of the
heavens, excepting a portion near the horizon, where it seemed to be
repelled. The upper white blink referred to ice about six miles
distant, being beyond the horizon; the narrow yellowish portions
referred to floes and compact ice; the lowest yellow blink, which in
brightness and colour resembled the moon, was the reflection of a field
at the distance of thirty miles, to which, directed by the blink, we
made way in the _Baffin_, through the channels of water represented in
the sky by bluish-grey streaks. The field we found to be a sheet of ice
150 miles in circumference!"
Another very singular appearance observed occasionally in foggy weather
is a series of bright circles, or coronae, surrounding the heads or
persons of individuals in certain positions. We have, while standing at
the mast-head of a vessel in Hudson's Straits, observed our own shadow
thrown on the sea with a bright halo round it. The day was bright and
hazy at the time. Referring to a particular case of this kind, Scoresby
says:
"During the month of July 1820, the weather being often foggy, with a
bright sun sometimes shining at the height of the day, some
extraordinary coronae were observed from the mast-head. These occurred
opposite to the sun, the centre of all the circles being in a line drawn
from the sun through the eye of the observer. On one occasion four
coloured luminous circles were observed. The exterior one might be
twenty degrees in diameter. It exhibited all the colours of the
spectrum. The next, a little within it, was of a whitish-grey colour;
the third was only four or five degrees in diameter, and though it
exhibited the colours of the spectrum, these colours were not very
brilliant. The fourth was extremely beautiful and brilliant. The
interior colour was yellow, then orange, red, violet, etcetera. The
colours of the whole three coronae were, I think, in the same order, but
of this I am not very certain. Indeed, on reflection, I suspect that
the second circle must have been in the reverse order of the first; the
first and the fourth being the same. The third was not coloured. In
the midst of these beautiful coronae I observed my own shadow, the head
surrounded by a glory. All the coronae were evidently produced by the
fog; my shadow was impressed on the surface of the sea."
The cause of these phenomena is "the reflection of the sun's rays,
decomposed by different refractions in minute globules of water, of
which the mist, wherein the coronae occur, in a great measure appears to
consist."
Mock suns, or _parhelia_, are common appearances in northern skies.
Sometimes two of these mock suns are seen, one on each side of their
great original, glowing so brightly that either of them, if we could
suppose it to have shone in the sky alone, would have made a very
respectable sun indeed! Even four of these "sun-dogs"--as they are some
times called--have been seen surrounding the sun; one on each side of
it, one directly above, and one immediately below, with a ring of light
connecting them together, a streak of light passing horizontally and
another passing perpendicularly between them, thus forming a luminous
cross, in the centre of which was the sun itself. This magnificent
spectacle is sometimes enhanced by a second circle of light enclosing
the whole, and the edges of several outer circles springing in faint
light therefrom until gradually lost, leaving the imagination to call up
the idea of an endless series of glories extending over the whole sky.
Refraction frequently causes grotesque as well as wonderful and
beautiful appearances. Ships are sometimes seen with their hulls
flattened and their masts and sails drawn out to monstrous dimensions;
or the hulls are heightened so as to appear like heavy castle walls,
while the masts and sails are rendered ludicrously squat and
disproportioned; and not only so, but ships are often seen with their
images inverted over their own masts, so that to the observer it appears
as if one ship were balancing another upside down--mast-head to
mast-head. Land and icebergs assume the same curious appearances--peaks
touching peaks, one set pointing upwards, the other set pointing down,
while the broad bases are elevated in the air. At other times the whole
mass of land and ice on the horizon is more or less broken up and
scattered about as if in confusion, yet with a certain amount of
regularity in the midst of it all, arising from the fact of every object
being presented in duplicate, sometimes triplicate, and occasionally,
though seldom, four-fold.
When sharp sudden frosts occur in those regions, the splendour of the
scenery is still further enhanced by the formation of innumerable minute
crystals which sparkle literally with as much lustrous beauty as the
diamond. On one occasion Scoresby's ship was decorated with uncommon
magnificence, and in a peculiarly interesting manner.
"In the course of the night," he writes, "the rigging of the ship was
most splendidly decorated with a fringe of delicate crystals. The
general form of these was that of a feather having half of the vane
removed. Near the surface of the ropes was first a small direct line of
very white particles, constituting the stem or shaft of the feather; and
from each of these fibres, in another plane, proceeded a short delicate
range of spiculae or rays, discoverable only by the help of a
microscope, with which the elegant texture and systematic construction
of the feather were completed. Many of these crystals, possessing a
perfect arrangement of the different parts corresponding with the shaft,
vane, and rachis of a feather, were upwards of an inch in length, and
three-fourths of an inch in breadth. Some consisted of a single flake
or feather, but many of them gave rise to other feathers, which sprang
from the surface of the vane at the usual angle. There seemed to be no
limit to the magnitude of these feathers, so long as the producing cause
continued to operate, until their weight because so great, or the action
of the wind so forcible, that they were broken off and fell in flakes to
the deck of the ship."
It is impossible for the mind to conceive the effect of such a galaxy of
curious, and bright, and eminently beautiful combinations as are
sometimes displayed in the arctic regions. None of the fabulous
conceptions of man, even though profoundly elaborated and brightly
gilded with the coruscations of the most sparkling genius and fancy,
ever produced so gorgeous a spectacle as may be witnessed there every
summer day. Four or five suns in the blue sky, with lines and circles
of light shooting from or circling round them! Ice in all its quaint,
majestic, and shining forms, rendered still more quaint and grand by the
influence of refraction; and, by the same power, ships sailing in the
sky, sometimes, as if Nature's laws were abrogated, with their keels
upwards, and their masts pointing to the sea! Walls of pure ice
hundreds of feet high, many miles in extent, clear as crystal, and
sending back the rays of heaven's luminaries in broad blazing beams;
while the icebergs' pinnacles reflect them in sparkling points! White
luminous fogs, like curtains of gauze, too thin to dim the general
brightness, yet dense enough to invest the whole scene with a silver
robe of mystery, and to refract the light and compel it to shine in
great circles of prismatic colours! And everything--from the nature of
the materials of which the gay scenery is composed--either white or
blue, varying in all gradations from the fairest snow to the deepest
azure, save where the rainbow's delicate hues are allowed to intermingle
enough of pink, yellow, purple, orange, and green to relieve the eye and
enable it more fully to appreciate the virgin drapery of the scene. All
this, seen in detail--seen frequently in rapid succession--sometimes
seen almost all at one moment,--all this is absolutely beyond
conception, and utterly beyond adequate description. Yet all this is
seen at times in those realms of ice and snow, which are, as we have
already said, too much represented as the "gloomy, forbidding,
inhospitable polar regions."
There are two sides to every picture. We take leave of this particular
branch of our sun with the remark, that if the shady side of the far
north is dreadfully dark and dreary, its bright side is intensely
brilliant and beautiful.