EARTH’S VAST OCEAN
“Thou great strong sea.”--AUBERON HERBERT.
“Drop by drop He counts
The flood of Ocean as it mounts.”--C. ROSSETTI.
In these days we know the Ocean as one vast whole. Not like our early
forefathers, standing on the brink, to gaze with awe-stricken eyes into
mysterious distances, and to speculate upon the unknown.
Minor oceans do exist, certainly. We have the Atlantic, North and
South; the Pacific, North and South; the Arctic, the Antarctic, and the
Indian. Yet for us there is but one great world-wide OCEAN, encircling
the Earth, every part being in connection with every other part.
A drop of water which to-day floats in southern seas may, months or
years hence, have found its way by currents into the far north. A speck
of ice, at this moment fast in the rigid embrace of polar berg or floe,
may, months or years hence, be washing to and fro in tropical waters.
A much greater area of water than of land is found upon the Earth’s
surface. So vast is the amount of the former that, if the whole had to
be put into separate vessels, each vessel being one cubic mile in size,
the number of such vessels required would amount to no less than _three
hundred and thirty-five millions_. This very large order speaks for
itself.
The outer Crust of our Earth, taking land and sea together, may be
divided into three distinct parts. Like most such divisions in Nature,
the one is often found to glide by gentle stages into another.
We have, first, Land, rising above the sea-level, and consisting of
plains, undulations, hills, mountains. It covers altogether less than
one-third of the Earth’s surface, and it is called THE CONTINENTAL
AREA, though Islands as well as Continents belong to it.
We have, secondly, the Ocean-floor under deeper parts of the Ocean;
that which lies beyond a depth of about two miles. This division has
been described as the “great submerged plain,” and it comprises about
one-half of the Earth’s surface. It is known as THE ABYSMAL AREA.
We have, thirdly, a middle region, which may be spoken of as a kind
of borderland under the sea, connecting the dry land with the greater
ocean-depths. It amounts to about one-sixth of the Earth’s surface, and
it has been named THE TRANSITIONAL AREA.
By “connecting” the two, I do not mean that it must always be between
the two. It does very generally so lie, but there are exceptions. Some
deeper portions of the sea are close to land, and some parts of the
Transitional Area are found far out at sea.
The meaning of the word “Continental” needs no explanation; and the
very word “Abysmal” carries its own sense. More, however, will be
said in future chapters about those reaches of ocean known as the
“Transitional Area.”
A curious law seems to have governed the grouping of land and water.
Putting aside innumerable small islands, scattered about, we find that
the great mass of land clusters towards and round the north pole, with
a water-and-ice-filled hollow for its centre. While, on the contrary,
the greater mass of water may be said to cluster towards and round the
south pole, with--so far as we can conjecture--a large extent of land
for its centre. The conditions of north and south thus seem to be
exactly reversed.
Not long ago it was believed that the ocean’s floor might be a fairly
close imitation of that which we see on land. The differences, however,
have been found to be greater than was expected. Perhaps it is not
surprising, when one thinks of the immense levelling power of water.
That must be a firm make of rock which can permanently resist the
effect of sea waves breaking upon or near the shore. And even deeper
down, where waves are not and currents may be slow, some movement must
still exist, since the ocean is nowhere quite stagnant. Such movements,
no matter how gentle, would tend to shift all loose and soft substances.
The ocean-bed is held to be generally flat, though with gradual slopes
here and there, leading up or down to higher or lower levels. Many
submarine mountains rear their heads, sometimes near the surface,
sometimes above it. In places high mountain-ridges run for a long
distance below the sea, with profound depths on either side; and these
again often show their peaks, forming groups of islands.
Broad reaches of the ocean are between two and three miles deep, and
here and there spots are found where the sounding-line goes sheer down
three miles, four miles, five miles, even six miles, before touching
bottom. These greater depressions have been named “Deeps.”
At least fifteen of them are known in the Atlantic, and twenty-four
in the Pacific; many of the latter lying close to islands. Some are
long in shape, some short; some are broad, some narrow. One of the
most profound, and almost the only one known to exceed five thousand
fathoms, lies towards the south-east of the Friendly Islands. A
depth there has been found five hundred and thirty feet beyond five
geographical miles; and five geographical miles are equal to almost six
of our common miles.
For a good while the notion was entertained that, probably, the
loftiest mountain-peak on land, and the deepest depth in the ocean,
would about match one another, reckoned from the sea-level. But this
particular “deep” in the Pacific sinks two thousand feet lower than
the topmost peak on Earth rises. Mount Everest, in the Himalayas,
is twenty-nine thousand feet high; and this ocean-depth is about
thirty-one thousand feet deep. Only one other equal to it has yet been
discovered.
No abyss divides England from France. The “silver streak,” though
sufficient for purposes of defence, is comparatively shallow. All
West Europe, indeed, rises from a plateau, reaching from Norway into
the Atlantic, on no part of which is the water more than six hundred
feet in depth. The “transitional area” in this case makes a true
stepping-stone or ledge between dry land and ocean’s abyss.
But another great plateau in the Atlantic, which may be called the
“backbone” of that Ocean, is far from land, running roughly from north
to south. It follows the outlines of the eastern and western shores,
and rises often to within a mile and a half of the surface. On either
side of the “backbone,” which seems to be largely volcanic, is a deep
trough, lying north and south, and varying in depth from two to four
miles. This plateau unites Europe with Iceland; and it forms a bond
between the Islands of the Azores, Ascension, and Tristan D’Acunha.
If by any means the whole ocean-surface could be lowered six hundred
feet, remarkable results would be seen.
At once the British Isles would cease to be Islands. They would become
a part of the Continent of Europe, joined thereto by dry land. The
Hebrides, the Orkneys, the Shetlands, would share in this change. The
Continents of Asia and North America would be united at the Behring
Straits; Ceylon would find itself a part of India; Papua and Tasmania
would be one with Australia; and all places hitherto on the coasts of
different countries would find themselves six hundred feet above the
sea.
Such a change in the position of the British Isles, transforming them
into a Continental Country, would mean far-reaching consequences to
ourselves as a People. One such consequence may be briefly given in
the words of a recent newspaper article: “Dry up the Atlantic to
the 100-fathom line, and in six months we should bear the load of
Conscription as cheerfully and more efficiently than any nation in
Europe.”
Suppose that another great fall in the ocean-surface could follow. Not
this time to six hundred feet, but to three thousand feet, below its
present level. The resulting alterations would be still more sweeping.
Not only Iceland and the Färoe Islands, but Greenland also--and not
only Greenland, but the Continent of North America itself--would become
one with the Continent of Europe, no longer cut off from the Old World.
A word as to measurements. Two kinds of “miles” have been mentioned.
There is the ordinary “Statute mile,” used in common conversation,
which is 880 fathoms, or 1,760 yards, in length. There is also the
“Geographical” or “Nautical” mile--the “knot” of our Navy--which is
1,013 fathoms or 2,026 yards in length.
The difference between the two is not far from one-eighth of a statute
mile. Roughly, seven miles are equal to six knots. A fathom is six feet
or two yards.