Frequently large pieces detach themselves spontaneously from an iceberg and fall into the sea with a tremendous noise. When this circumstance, called “calving,” takes place, the iceberg loses its equilibrium, sometimes turns on one side, and is occasionally inverted.
Dr. Hayes witnessed the crumbling of an immense berg, resembling in its general appearance the British House of Parliament. First one lofty tower came tumbling into the water, starting from its surface an immense flock of gulls; then another followed; and at length, after five hours of rolling and crashing, there remained of this splendid mass of congelation not a fragment that rose fifty feet above the water.
One of the most remarkable phenomena of the Polar Sea is the ice-blink, or reflection of the ice against the sky. A stripe of light, similar to the early dawn of morning, but without its redness, appears above the horizon, and traces a complete aërial map of the ice to a distance of many miles beyond the ordinary reach of vision. To the experienced navigator the “blink” is frequently of the greatest use, as it not only points out the vicinity of the drift-ice, but indicates its nature, whether compact or loose, continuous or open. Thus Scoresby relates that on the 7th of June, 1821, he saw so distinct an ice-blink, that as far as twenty or thirty miles all round the horizon he was able to ascertain the figure and probable extent of each ice-field. The packed ice was distinguished from the larger fields by a more obscure and yellow color; while each water-lane or open passage was indicated by a deep blue stripe or patch. By this means he was enabled to find his way out of the vast masses of ice in which he had been detained for several days, and to emerge into the open sea.
The tendency of the pack-ice to separate in calm weather, so that one might almost be tempted to believe in a mutual repulsive power of the individual blocks, is likewise favorable to the Arctic navigator. The perpetual daylight of summer is another advantage, but unfortunately the sun is too often veiled by dense mists, which frequently obscure the air for weeks together, particularly in July. These fogs, which are a great impediment to the whaler’s operations, have a very depressing influence upon the spirits; and as they are attended with a low temperature, which even at noon does not rise much above freezing-point, the damp cold is also physically extremely unpleasant.
At other times the sun sweeps two or three times round the pole without being for a moment obscured by a cloud, and then the transparency of the air is such that objects the most remote may be seen perfectly distinct and clear. A ship’s top-gallant mast, at the distance of five or six leagues, may be discerned when just appearing above the horizon with a common perspective-glass, and the summits of mountains are visible at the distance of from sixty to a hundred miles.
On such sunny days, the strong contrasts of light and shade between the glistening snow and the dark protruding rocks produce a remarkable deception in the apparent distance of the land, along a steep mountainous coast. When at the distance of twenty miles from Spitzbergen, for instance, it would be easy to induce even a judicious stranger to undertake a passage in a boat to the shore, from a belief that he was within a league of the land. At this distance the portions of rock and patches of snow, as well as the contour of the different hills, are as distinctly marked as similar objects in many other countries, not having snow about them, would be at a fourth or a fifth part of the distance.
Nothing can be more wonderful than the phenomena of the atmosphere dependent on reflection and refraction, which are frequently observed in the Arctic seas, particularly at the commencement or approach of easterly winds. They are probably occasioned by the commixture, near the surface of the land or sea, of two streams of air of different temperatures, so as to occasion an irregular deposition of imperfectly condensed vapor, which when passing the verge of the horizon apparently raises the objects there situated to a considerable distance above it, or extends their height beyond their natural dimensions. Ice, land, ships, boats, and other objects, when thus enlarged and elevated, are said to loom. The lower part of looming objects are sometimes connected with the horizon by an apparent fibrous or columnar extension of their parts; at other times they appear to be quite lifted into the air, a void space being seen between them and the horizon.
A most remarkable delusion of this kind was observed by Scoresby while sailing through the open ice, far from land. Suddenly an immense amphitheatre inclosed by high walls of basaltic ice, so like natural rock as to deceive one of his most experienced officers, rose around the ship. Sometimes the refraction produced on all sides a similar effect, but still more frequently remarkable contrasts. Single ice-blocks expanded into architectural figures of an extraordinary height, and sometimes the distant, deeply indented ice-border looked like a number of towers or minarets, or like a dense forest of naked trees. Scarcely had an object acquired a distinct form, when it began to dissolve into another.
It is well known that similar causes produce similar effects in the warmer regions of the earth. In the midst of the tropical ocean, the mariner sees verdant islands rise from the waters, and in the treeless desert fantastic palm-groves wave their fronds, as if in mockery of the thirsty caravan.
When we consider the intense cold which reigns during the greatest part of the year in the Arctic regions, we might naturally, expect to find the whole of the Polar Sea covered, during the winter at least, with one solid unbroken sheet of ice. But experience teaches us that this is by no means the case; for the currents, the tides, the winds, and the swell of a turbulent ocean are mighty causes of disruption, or strong impediments to congelation. Both Lieutenant de Haven and Sir Francis M’Clintock[1] were helplessly carried along, in the depth of winter, by the pack-ice in Lancaster Sound and Baffin’s Bay. A berg impelled by a strong under-current rips open an ice-field as if it were a thin sheet of glass; and in channels, or on coasts where the tides rise to a considerable height, their flux and reflux is continually opening crevices and lanes in the ice which covers the waters. That even in the highest latitudes the sea does not close except when at rest, was fully experienced by Dr. Hayes during his wintering at Port Foulke; for at all times, even when the temperature of the air was below the freezing-point of mercury, he could hear from the deck of his schooner the roar of the beating waves. From all these causes there has at no point within the Arctic Circle been found a firm ice-belt extending, either in winter or in summer, more than from fifty to a hundred miles from land. And even in the narrow channels separating the islands of the Parry Archipelago, or at the mouth of Smith Sound, the waters will not freeze over, except when sheltered by the land, or when an ice-pack, accumulated by long continuance of winds from one quarter, affords the same protection.