The Ocean and its Wonders Part 6

"On the 16th, another rush drove irresistibly on the larboard quarter and stern, and forcing the ship ahead, raised her on the ice. A chaotic ruin followed... The ship was careened fully four streaks, and sprang a leak as before. Scarcely were ten minutes left us for the expression of our astonishment that anything of human build could outlive such a.s.saults, when another equally violent rush succeeded; and in its way toward the starboard quarter threw up a rolling wave thirty feet high, crowned by a blue square ma.s.s of many tons, resembling the entire side of a house, which, after hanging for some time in doubtful poise on the ridge, at length fell with a crash into the hollow, in which, as in a cavern, the after-part of the ship seemed embedded. It was, indeed, an awful crisis, rendered more frightful from the mistiness of the night and dimness of the moon.

"The poor ship cracked and trembled violently, and no one could say that the next minute would not be her last--and, indeed, his own too, for with her our means of safety would probably perish."

It is unnecessary to give additional instances of this kind, in order to show the terrible power of field-ice. Indeed, it requires little in the way of illumination to prove that ma.s.ses of solid matter, many thousands of tons in weight, can, when in motion, utterly destroy the most powerful engines of human construction.

We shall now turn our attention to another, and a very prominent form, in which arctic ice presents itself--namely, that of icebergs.

CHAPTER TEN.

ICEBERGS--THEIR APPEARANCE AND FORMS--THEIR CAUSE--GLACIERS--THEIR NATURE AND ORIGIN--ANECDOTE OF SCORESBY--RISK AMONG ICEBERGS--MCCLURE'S EXPERIENCE.

There are not only ice-fields, ice-floes, etcetera, in the polar seas, but there are ice-mountains, or bergs.

It was long a matter of uncertainty as to where and how those immense mountains, that are met with occasionally at sea, were formed. We are now in a position to tell definitely where they originate, and how they are produced. They are not ma.s.ses of frozen sea water. Their birth-place is in the valleys of the far north, and they are formed by the acc.u.mulation of the snows and ice of ages. This is a somewhat general way of stating the matter; but our subsequent explanations will, we trust, make our meaning abundantly clear.

Icebergs are found floating in great numbers in the arctic seas. They drift southward each spring with the general body of polar ice, and frequently travel pretty far south in the Atlantic before the heat of the water and atmosphere united accomplishes their dissolution. They sometimes travel as far south as Florida with the southerly current that flows along that coast; but the warm waters of the Gulf Stream, together with its northerly flow, form an impa.s.sable barrier between these ice-mountains and Europe.

Icebergs a.s.sume every variety of form, and almost every size. They sometimes resemble castles, sometimes churches with glittering spires, and sometimes the peaked and jagged mountains of Norway. They are also frequently seen in the form of immense misshapen and top-heavy ma.s.ses.

In size they vary from one hundred to seven or eight hundred feet in height. One iceberg, seen by Ross in Baffin's Bay, was above two miles in length, nearly the same in width, and fifty feet high. But in stating this, we have not given the reader any idea of its vast proportions; for it is well known that all icebergs, or ma.s.ses of ice, have a much greater proportion of their bulk under than above water--in other words, they sink very deep. The relative proportion that sinks depends on the nature of the ice. Of some kinds, there is usually ten times as much below as there is above water; of other kinds, there may be eight or five parts below. In all cases there is much more below than above so that a mountain of a hundred feet high--if afloat--may be safely calculated to be a ma.s.s of ice not far short of a thousand feet thick.

As these bergs float southward with the currents, they melt very rapidly. The heat of the sun and the action of the waves gradually round off the sharp angles and topple down the spires that characterised them in the land of their birth. The process of dissolution, too, is carried on internally; for rain and melted water on the surface percolates through the ma.s.s, rendering it porous. As the waves cut away the base, the centre of gravity is thrown out, and the whole berg turns over with a terrible crash. Sometimes loud reports like cannon-shots are heard, and the huge mountain splits asunder; while, not unfrequently, the whole berg falls into a heap of chaotic ruins, and floats away in a ma.s.s of smaller pieces which disappear gradually in their parent sea.

The formation of icebergs has, as we have said, puzzled mankind for many years. Their existence has long been known: for, even before men dared to venture their lives in the polar regions, navigators, in crossing the Atlantic Ocean, frequently met with these marble-like mountains; and, what is worse, sometimes ran at full speed against them, and were sunk with all on board. Bergs are frequently enveloped in dense fogs, caused by the cold atmosphere by which they are surrounded condensing the moisture of the warmer atmosphere which they encounter on their voyage southward; hence they are exceedingly dangerous to navigation. But now to speak of their formation.

Many of the great valleys of the far north are completely filled up with solid ice. Observe, we do not say that they are merely covered over with ice; they are absolutely filled up with it from top to bottom.

Those ice-ma.s.ses are known by the name of glaciers; and they are found in most of the elevated regions of the Earth,--on the Alps and the mountains of Norway, for instance,--but they exist in greater abundance about the poles than elsewhere.

Glaciers _never_ melt. They have existed for unknown ages, probably since the world began; and they will, in all likelihood, continue to exist until the world comes to an end,--at least until the present economy of the world terminates. They began with the first fall of snow, and as falls of snow during the long winters of the polar regions are frequent and heavy, the acc.u.mulated ma.s.ses are many feet deep, especially in places where drifts are gathered--sometimes fifteen, twenty, thirty, and even forty feet deep. The summer sun could not melt such drifts entirely. New snow was added each winter, until the valleys of the far north were filled up; and so they remain filled up to this day.

In order to understand the nature of glaciers clearly, let us turn back to those remote ages that rolled over this Earth long before man was created. Let us in spirit leap back to the time when no living creature existed, even before the great mastodon began to leave his huge foot-prints on the sands of time.

We have reached one of the large valleys of the arctic regions. It is solemn, grand, and still. No merry birds, no prowling creatures, are there to disturb the universal calm. The Creator has not yet formed the living creatures and p.r.o.nounced them "very good." It is the world's first winter. As we look upward to the sky, we observe the first white snow-flakes falling gently to the ground. They reach it, and, for the first time, that valley is covered with a garment of virgin snow. The valley is upwards of two miles broad. It rises from the sea, and goes far back into the mountains, perhaps to the extent of ten or twelve miles. The mountains that flank it are five or six thousand feet high.

We have seen such valleys in Norway, within the arctic circle. Before that first winter has pa.s.sed, many and many a fall of snow has thickened and pressed down that first coat; and many a furious storm has caught up the snow from the mountain-tops and swept it into the valley, adding to and piling up the ma.s.s, and packing it firmly down.

Spring arrives. The short but warm arctic summer bursts upon that vale, melting the surface of the snow; and the water thus produced sinks through the ma.s.s, converting it into a sort of thick slush--half snow, half water,--not liquid, yet not solid; just solid enough to lie there apparently without motion; yet just liquid enough to creep by slow, absolutely imperceptible degrees, down the valley. The snow in all the mountain gorges is similarly affected: it creeps (it cannot be said to flow) out and joins that in the vale. But we cannot perceive any of the motion of which we are writing. The ma.s.s of snow seems to be as still and motionless as the rocks on which we stand; nay, if we choose we may walk on its hard surface almost without leaving the slightest print of our foot. But if we throw a large stone on the surface of the snow and mark the spot, and return again after many days, we shall find that the stone has descended the valley a short distance. We shall also observe that the snow has now a variety of markings on its surface; which might lead us to fancy, had we not known better, that it had once been a river, which, while raging down to the sea with all its curling rapids and whirling eddies, had been arrested in all instant by the ice-king and frozen solid,--in fact, it has all the graceful lines and forms of fluidity, with all the steady, motionless aspect of solidity. It really moves, this vast body of snow; but, like the hour hand of a watch, its motion cannot be recognised, though we should observe it with prolonged, unflagging attention. We have called it a vast body of snow, but this is only comparatively speaking. It will be vaster yet before we have done with it. At present it is but a thick semi-fluid covering, lying at the bottom of this ancient arctic vale.

The brief summer ends. Much of the winter snow has been melted and returned to the sea; but much, very much more, is still lying deep upon the ground. The world's second winter comes. The first frost effectually puts a stop to all the melting and moving that we have been describing. The snow-river no longer moves--it is arrested. The water no longer percolates through the snow--it is frozen. The ma.s.s is no longer semi-fluid--it is solid ice; and the first step in the process of a glacier's formation is begun.

Thereafter this process is continued from year to year, each winter adding _largely_ to its bulk, each summer deducting _slightly_ therefrom. The growing ma.s.s of ice ascends the mountain-sides, swallows the rocks and shrubs and trees in its progress, until its body becomes a thousand feet thick: the extreme summits of the mountain-peaks alone tower above the snowy waste, and the ma.s.s at the bottom is now, by the pressure of superinc.u.mbent ma.s.ses, pure ice, hard and clear as crystal.

When the great glacier grows old it still maintains its stealthy downward motion during every summer. It has reached the sh.o.r.e, and has been pushed, like a huge white tongue, out into the sea.

"But what has all this to do with icebergs?" it may be inquired. Much, very much. It is common enough, in commenting on a child, to speak of the parent. The glacier is the _mother_ of the iceberg.

When, in the world's early morning, the embryo glacier reached the sea, its thin edges were easily broken off by the waves; but as it increased and still further encroached, these edges became thicker and thicker, until at last a wall of pure ice, several hundred feet high, presented its glittering front to the ocean. It was hard and ma.s.sive; the sun of summer had little effect on its frigid face, and it seemed to bid defiance to the sea itself. But things often are not what they seem.

Each billow sapped its foundation; it soon began to overhang its base.

At length the cohesion of the ma.s.s was not sufficient to sustain its weight. A rending, accompanied by sounds like heaven's artillery, took place; the crystal mountain bowed its brow and fell with thunderous crash upon the water; then, rocking slowly under the impulse of its dread plunge, the first iceberg floated off to sea!

It is right to remark here that this explanation is, to some extent, disputed--at least there is a difference of opinion as to the _manner_ in which the iceberg leaves its parent glacier. There is no dispute as to its origin. This difference will be explained shortly in a quotation from Dr Kane's work; meanwhile, in support of the present theory, let us listen to the words of one who saw with his own eyes something similar to what has been described. Dr Scoresby, than whom a better man never explored the arctic seas, says:--

"In July 1818, I was particularly fortunate in witnessing one of the grandest effects which these polar glaciers ever present. A strong north-westerly swell, having for some hours been beating on the sh.o.r.e, had loosened a number of fragments attached to the iceberg, and various heaps of broken ice denoted recent shoots of the seaward edge. As we advanced towards it, with a view of proceeding close to its base, I observed a few little pieces fall from the top; and while my eye was fixed upon the place, an immense column, probably fifty feet square, and one hundred and fifty feet high, began to leave the parent ice at the top, and, leaning majestically forward, with an accelerated velocity fell, with an awful crash, into the sea.

"The water into which it plunged was converted into an appearance of vapour or smoke, like that from a furious cannonading. The noise was equal to that of thunder, which it nearly resembled. The column which fell was nearly square, and in magnitude resembled a church. It broke into thousands of pieces. This circ.u.mstance was a happy caution, for we might inadvertently have gone to the very base of the icy cliff from whence ma.s.ses of considerable magnitude were continually breaking!"

Now, this incident suggests the probability, that, had the face of the glacier projected into deep water, the ma.s.s which broke off might have fallen into the sea without being broken to pieces, and might have floated away as a berg. We confess, however, to be partial to the view expressed by some writers, that the great glaciers continue year by year to thrust their thick tongues out to sea, until the projecting ma.s.ses reach water sufficiently deep to float them, when they are quietly cracked off from their parent and carried away without any fall or plunge. The following remarks by Dr Kane will make this more clear.

Writing of the iceberg, he says:

"So far from falling into the sea, broken by its weight from the parent glacier, it rises from the sea. The process is at once gradual and comparatively quiet. The idea of icebergs being discharged, so universal among systematic writers, and so recently admitted by myself, seems to me at variance with the regulated and progressive action of nature. Developed by such a process, the thousands of bergs which throng these seas should keep the air and water in perpetual commotion-- one fearful succession of explosive detonations and propagated waves.

But it is only the lesser ma.s.ses falling into deep waters which could justify the popular opinion. The enormous ma.s.ses of the Great Glacier [of Greenland] are propelled step by step, and year by year, until, reaching water capable of supporting them, they are floated off, to be lost in the temperatures of other regions...

"The height of the ice-wall at the nearest point was about three hundred feet, measured from the water's edge; and the unbroken right line of its diminishing perspective showed that this might be regarded as its constant measurement. It seemed, in fact, a great icy table-land, ab.u.t.ting with a clean precipice against the sea. This is, indeed, characteristic of all those arctic glaciers which issue from central reservoirs, or _mers de glace_, upon the fords or bays, and is strikingly in contrast with the dependent or hanging glacier of the ravines."

Elsewhere the same writer speaks of this glacier as a line of cliff, rising in a solid gla.s.sy wall to a height of three hundred feet above the water-level, and with an _unfathomable_ depth below it; and its curved face, sixty miles in length, from Cape Aga.s.siz to Cape Forbes, vanished into unknown s.p.a.ce at not more than a single day's rail-road travel from the pole. The interior with which it communicated, and from which it issued, was an unsurveyed _mer de glace_, or sea of ice, of apparently boundless dimensions; and from one part of this great cliff he _saw_ long lines of huge bergs floating slowly away.

Here, we think, is ice enough and of sufficient dimensions to account for the largest bergs that were ever beheld.

It will be at once seen, then, that icebergs, though found floating in the sea, are not necessarily of the sea. They are composed entirely of fresh water, and arctic ships can at any time procure a plentiful supply of good soft drinkable water from the pools that are formed in the hollows of the bergs.

The risk of approaching icebergs in the arctic regions is not so great as when they are found floating further south; because when in their native regions they are comparatively tough, whereas on their southern journeys they become more or less disintegrated--in fact, the blow of an axe is sometimes sufficient to cause a rent, which in its turn will induce other rents and failings asunder, so that the whole ma.s.s runs the risk of being entirely broken up. Hence the danger of ships, in certain circ.u.mstances, venturing to anchor to them. Nevertheless this is a common practice--sometimes a necessity--among discovery ships and whalers. It is a convenient practice too; for many a vessel has been saved from absolute destruction by getting under the lee of a good sound iceberg, where she has lain as safely, for the time being, as if in a harbour.

When Captain McClure was endeavouring to make the north-west pa.s.sage in 1851, he was saved, from what appeared to be at least very probable destruction, by a small iceberg. On the 17th of September he writes:

"There were several heavy floes in the vicinity. One, full six miles in length, pa.s.sed at the rate of two knots, crushing everything that impeded its progress, and grazed our starboard-bow. Fortunately there was but young ice upon the opposite side, which yielded to the pressure; had it otherwise occurred, the vessel must inevitably have been cut asunder. In the afternoon we secured to a moderately-sized iceberg, drawing eight fathoms, which appeared to offer a fair refuge, and from which we never afterwards parted."

To this lump of ice the ship clung with the tenacity of a bosom friend, and followed it, literally, through thick and thin! There is something almost ludicrous, as well as striking, in McClure's account of their connection with this bit of ice. It conveyed them to their furthest north-east position, and back round the Princess Royal Islands--pa.s.sed the largest within five hundred yards--returned along the coast of Prince Albert's Land--and finally froze in at lat.i.tude 70 degrees 50 minutes north, longitude 117 degrees 55 minutes west, on the 30th September; during which circ.u.mnavigation they received many severe "nips," and were frequently driven close to the sh.o.r.e, from which their dear friend the iceberg, small though he was, kept them off.

Icebergs a.s.sume almost every conceivable form, and are seen of every size--sometimes, also, in great numbers. Scoresby mentions one occasion on which he was surrounded by bergs to the number of several hundreds.

Now, all this ice that we have been speaking of, besides being, in a secondary way, a pa.s.sive agent in the affairs of man (chiefly in barring his progress northward), is one of the most potent agents in the economy of nature. It is the means by which the world is kept cool enough for man and beast to dwell in. The polar regions--north and south--are, as it were, the world's refrigerators; tempering the heated air of the south, and, in connection with the torrid zone, spreading throughout the Earth those beneficial influences which gladden the sphere of man's temporal existence.

CHAPTER ELEVEN.

ICE AN AGENT IN TRANSPORTING BOULDERS--HOW THIS COMES ABOUT--DR. KANE'S OBSERVATIONS--LONG NIGHT IN WINTER AND LONG DAY IN SUMMER--EXTREME DARKNESS--INFLUENCE ON DOGS--INTENSE COLD--EFFECT ON THE SEA.

There are many things in this world which, up to within a few years back, have been to men a source of surprise and mystery.

Some of these problems have been solved by recent travellers, and not a few of them are referable to polar oceans and ice.

In many parts of our coasts we find very striking and enormously large boulder-stones lying on the beach, perfectly isolated, and their edges rounded away like pebbles, as if they had been rolled on some antediluvian beach strewn with t.i.tanic stones. These boulders are frequently found upon the loose sands of the sea-sh.o.r.e, far removed from any rocks or mountains from which they might be supposed to have been broken; and, more than that, totally different in their nature from the geological formations of the districts in which they are found. "Whence came these?" has been the question of the inquisitive of all ages, "and how came they there?"

There may, for aught we know to the contrary, be more than one answer to these questions; but there is at least one which is quite satisfactory as to how and whence at least some of them have come. Ice was the means of conveying these boulders to their present positions.

It has been said that once upon a time a large part of this country was under the dominion of ice, even as the polar regions and some of the mountains and valleys of Norway are at the present day; that the boulders we see in elevated places were conveyed thither by glacier action; and that when the glacial period pa.s.sed away, they were left there on the hill-sides--sometimes almost on the mountain-tops. But this is not the question we are considering just now. We are now inquiring into the origin of those huge boulders that are found upon our coasts and on the coasts of other lands--boulders which could not have rolled down from the hills, for there are no hills at all near many of them; and those hills that are near some of them are of different geological formation.