The Ocean and its Wonders, Robert Michael Ballantyne [portable ebook reader txt] 📗

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 passage 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, passed 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--passed the largest within five hundred yards--returned along the coast of Prince Albert's Land--and finally froze in at latitude 70 degrees 50 minutes north, longitude 117 degrees 55 minutes west, on the 30th September; during which circumnavigation they received many severe "nips," and were frequently driven close to the shore, from which their dear friend the iceberg, small though he was, kept them off.

Icebergs assume 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 passive 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 Titanic stones. These boulders are frequently found upon the loose sands of the sea-shore, 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 passed 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.

This question will be answered at once, and one of the phenomena of arctic ice and oceanic agency will be exhibited, by reference to the recent discoveries of the celebrated arctic voyager, Dr Kane of the American Navy.

While wintering far beyond the head of Baffin's Bay, and beyond the most northerly point, in that direction, that had at that time been reached by any previous traveller, Dr Kane made many interesting observations and discoveries. He seems to have penetrated deep into the heart of Nature's northern secrets. Among other things, he ascertained the manner in which boulders are transported from their northern home.

The slow, creeping movement of glaciers, to which we have already referred, is one means whereby large boulders are formed. At the lower edge of one of the glaciers of Norway we saw boulders, thirty or forty feet in diameter, which had been rolled and forced, probably for ages, down the valley by the glacier, and thrust out on the sea-beach, where they lay with their angles and corners rubbed off and their surfaces rounded and smoothed as completely as those of the pebbles by which they were surrounded.

Had these boulders been formed in the arctic regions, they might have been thrust out upon the thick solid crust of the frozen sea, which in time would have been broken off and floated away; thus rafting the boulders to other shores. The formation of boulders, and their positions, are facts that we have seen. Their being carried out to sea by ice-rafts is a fact that Dr Kane has seen and recorded. On the wild rocky shores where his ship was set fast, there was a belt of ice lining the margin of the sea, which he termed the "ice-belt," or the "ice-foot." This belt never melted completely, and was usually fast to the shore. In fact it was that portion of the sea-ice which was left behind each spring when the general body of ice was broken up and swept away. Referring to this, he writes:

"The spot at which we landed I have called Cape James Kent. It was a lofty headland, and the land-ice which hugged its base was covered with rocks from the cliffs above. As I looked over this ice-belt, losing itself in the far distance, and covered with its millions of tons of rubbish, greenstones, limestones, chlorite, slates, rounded and angular, massive and ground to powder, its importance as a geological agent, in the transportation of drift, struck me with great force.

"Its whole substance was studded with these varied contributions from the shore; and further to the south, upon the now frozen waters of Marshall Bay, I could recognise raft after raft from the last year's ice-belt which had been caught by the winter, each one laden with its heavy freight of foreign material.

"The water torrents and thaws of summer unite with the tides in disengaging the ice-belt from the coast; but it is not uncommon for large bergs to drive against it and carry away the growths of many years. I have found masses that had been detached in this way, floating many miles out at sea--long, symmetrical tables, two hundred feet long by eighty broad, covered with large angular rocks and boulders, and seemingly impregnated throughout with detrited matter. These rafts in Marshall Bay were so numerous, that could they have melted as I saw them, the bottom of the sea would have presented a more curious study for the geologist than the boulder-covered lines of our middle latitudes. One boulder in particular had had its origin in a valley where rounded fragments of water-washed greenstone had been poured out by the torrents and frozen into the coast-ice of the belt. The attrition of subsequent matter had truncated the great egg-shaped rock, and worn its sides into a striated face, whose scratches still indicated the line of water-flow."

So, then, when we next meet with a huge isolated boulder on any of our flat beaches, we may gaze at it with additional interest, when we reflect that, perchance, it was carried thither by the ocean, countless ages ago, from the arctic regions, on a gigantic raft of ice; after having been, at a still more remote period, torn from its cliffs by some mighty glacier and slowly rolled and rounded, for hundreds of years perhaps down the scarred slopes of its native valley.

The primary cause of the intense and prolonged cold of the arctic regions is the shortness of the time during which they are under the influence of the sun's rays. For a few months in summer the sun shines brightly, but, owing to the position of the globe, obliquely on the poles. During part of that period it shines at mid-night as well as at mid-day. Put during the greater part of the year its beams throw but a feeble light there, and for several months in winter there is absolutely no day at all--nothing but one long dismal night of darkness, that seems as if the bright orb of day had vanished from the heavens for ever.

The length of this prolonged day in summer, and this dreary night in winter, depends, of course, upon latitude. The length of both increases as we approach the poles. The long daylight in summer is exceedingly delightful. We once saw the sun describe an almost unbroken circle in the sky for many days and nights, and had we been a few degrees further north we should have seen it describe an entire circle. As it was, it only disappeared for twenty minutes. It set about midnight, and in twenty minutes it rose again so that there was no night, not even twilight, but a bright, beautiful blazing day, for several weeks together.

Dr Kane describes the midnight sun thus: "On our road we were favoured with a gorgeous spectacle, which hardly any excitement of peril could have made us overlook. The midnight sun came out over the northern crest of the great berg, our late `fast friend,' kindling variously-coloured fires on every part of its surface, and making the ice around us one great resplendency of gem-work--blazing carbuncles and rubies, and molten gold."

Very different indeed is the aspect of the winter night. Let the same authority speak, for he had great experience thereof.

On December 15th he writes: "We have lost the last vestige of our mid-day twilight. We cannot see print, and hardly paper. The fingers cannot be counted a foot front the eyes. Noonday and midnight are alike; and, except a vague glimmer on the sky, that seems to define the hill-outlines to the south, we have nothing to tell us that this arctic world of ours has a sun. In one week more we shall reach the midnight of the year...