(Anas caudacuta et glacialis), the latest visitors of the season. These birds generally take their departure in the same order as they arrive. The period of their stay is but short, but their presence imparts a wonderfully cheerful aspect to regions at other times so deserted and dreary. As soon as the young are sufficiently fledged, they again betake themselves to the southward; the character of the season much influencing the period of their departure.

As far as man has penetrated, on the most northern islets of Spitzbergen, or on the ice-blocked shores of Kennedy Channel, the eider duck and others of the Arctic anatidæ build their nests; and there is no reason to doubt that, if the pole has breeding-places for them, it re-echoes with their cries. Nor need they fear to plunge into the very heart of the Arctic zone, for the flight of a goose being forty or fifty miles an hour, these birds may breed in the remotest northern solitude, and in a few hours, on a fall of deep autumn snow, convey themselves by their swiftness of wing to better feeding grounds.

One of the most interesting of the Arctic birds is the snowbunting (Plectrophanes nivalis), which may properly be called the polar singing bird, as it breeds in the most northern isles, such as Spitzbergen and Novaja Zemlya, or on the highest mountains of the Dovrefjeld in Scandinavia, where it enlivens the fugitive summer with its short but agreeable notes, sounding doubly sweet from the treeless wastes in which they are heard. It invariably builds its nest, which it lines with feathers and down, in the fissures of mountain rocks or under large stones, and the entrance is generally so narrow as merely to allow the parent birds to pass. The remarkably dense winter plumage of the snow-bunting especially qualifies it for a northern residence, and when in captivity it will rather bear the severest cold than even a moderate degree of warmth. In its breeding-places it lives almost exclusively on insects, particularly gnats: during the winter it feeds on all sorts of seeds, and then famine frequently compels it to wander to a less rigorous climate.

The Lapland bunting (Centrophanes lapponicus), whose white and black plumage is agreeably diversified with red, is likewise an inhabitant of the higher latitudes, where it is frequently seen in the barren grounds and tundras. Both

these birds are distinguished by the very long claw of their hind toe, a structure which enables them to run about with the snow.

ease upon

Among the raptorial birds of the Arctic regions, the seaeagle (Haliatus albicilla) holds a conspicuous rank. At his approach the gull and the auk conceal themselves in the fissures of the rocks, but are frequently dragged forth by their relentless enemy. The divers are, according to Wahlengren, more imperilled from his attacks than those seabirds which do not plunge, for the latter rise into the air as soon as their piercing eye espies the universally dreaded tyrant, and thus escape; while the former, blindly trusting to the element in which they are capable of finding a temporary refuge, allow him to approach, and then suddenly diving, fancy themselves in safety, while the eagle is only waiting for the moment of their reappearance to repeat his attack. Twice or thrice they may possibly escape his claws by a rapid plunge, but when for the fourth time they dive out of the water, and remain but one instant above the surface, that instant seals their doom. The sea-eagle is equally formidable to the denizens of the ocean, but sometimes too great a confidence in his strength leads to his destruction, for Kittlitz was informed by the inhabitants of Kamtschatka that, pouncing upon a dolphin, he is not seldom dragged down into the water by the diving cetacean in whose skin his talons remain fixed.

Dangers peculiar to the Arctic Sea Ice-fields-Hummocks-Collision of Icefields-Ice-bergs-Their Origin-Their Size-The Glaciers which give them Birth-Their Beauty-Sometimes useful Auxiliaries to the Mariner-Dangers of Anchoring to a Berg-A crumbling Berg-The Ice-blink-Fogs-Transparency of the Atmosphere-Phenomena of Reflection and Refraction-Causes which prevent the Accumulation of Polar Ice-Tides-Currents-Ice a bad Conductor of Heat-Wise Provisions of Nature.

THE

HE heart of the first navigator, says Horace, must have been shielded with threefold brass-and yet the poet knew but the sunny Mediterranean, with its tepid floods and smiling shores how, then, would he have found words to express his astonishment at the intrepid seamen who, to open new vistas to science or new roads to commerce, first ventured to face the unknown terrors of the Arctic main?

In every part of the ocean the mariner has to guard against the perils of hidden shoals and sunken cliffs, but the high northern waters are doubly and trebly dangerous; for here, besides those rocks which are firmly rooted to the ground,

there are others which, freely floating about, threaten to crush his vessel to pieces, or to force it along with them in helpless bondage.

The Arctic navigators have given various names to these movable shoals, which are the cause of so much delay and danger. They are ice-bergs when they tower to a considerable height above the waters, and ice-fields when they have a vast horizontal extension. A floe is a detached portion of a field; pack-ice, a large area of floes or smaller fragments closely driven together so as to oppose a firm barrier to the progress of a ship; and drift-ice, loose ice in motion, but not so firmly packed as to prevent a vessel from making her way through its yielding masses.

The large ice-fields which the whaler encounters in Baffin's Bay, or on the seas between Spitzbergen and Greenland, constitute one of the marvels of the deep. There is a solemn grandeur in the slow majestic motion with which they are drifted by the currents to the south; and their enormous masses, as mile after mile comes floating by, impress the spectator with the idea of a boundless extent and an irresistible power. But, vast and mighty as they are, they are unable to withstand the elements combined for their destruction, and their apparently triumphal march leads them only to their ruin.

When they first descend from their northern strongholds, the ice of which they are composed is of the average thickness of from ten to fifteen feet, and their surface is sometimes tolerably smooth and even, but in general it is covered with numberless ice-blocks or hummocks piled upon each other in wild confusion to a height of forty or fifty feet, the result of repeated collisions before flakes and floes were soldered into fields. Before the end of June they are covered with snow, sometimes six feet deep, which melting during the summer forms small ponds or lakes upon their surface.

Not seldom ice-fields are whirled about in rotatory motion, which causes their circumference to gyrate with a velocity of several miles per hour. When a field thus sweeping through the waters comes into collision with another which may possibly be revolving with equal rapidity in an opposite direction-when masses not seldom twenty or thirty miles in

ICE-BERGS AND ICE-FIELDS.

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diameter, and each weighing many millions of tons, clash together, imagination can hardly conceive a more appalling scene. The whalers at all times require unremitting vigilance to secure their safety, but scarcely in any situation so much as when navigating amidst these fields, which are more particularly dangerous in foggy weather, as their motions cannot then be distinctly observed. No wonder that since the establishment of the fishery numbers of vessels have been crushed to pieces between two fields in motion, for the strongest ship ever built must needs be utterly unable to resist their power. Some have been uplifted and thrown upon the ice; some have had their hulls completely torn open; and others have been overrun by the ice, and buried beneath the fragments piled upon their wreck.

The ice-bergs, which, as their name indicates, rise above the water to a much more considerable height than the icefields, have a very different origin, as they are not formed in the sea itself, but by the glaciers of the northern highlands. As our rivers are continually pouring their streams into the ocean, so many of the glaciers or ice-rivers of the Arctic zone, descending to the water-edge, are slowly but constantly forcing themselves further and further into the sea. In the summer season, when the ice is particularly fragile, the force of cohesion is often overcome by the weight of the prodigious masses that overhang the sea or have been undermined by its waters; and in the winter, when the air is probably 40° or 50° below zero and the sea from 28° to 30° above, the unequal expansion of those parts of the mass exposed to so great a difference of temperature cannot fail to produce the separation of large portions.

Most of these swimming glacier-fragments, or ice-bergs, which are met with by the whaler in the Northern Atlantic, are formed on the mountainous west coast of Greenland by the large glaciers which discharge themselves into the fiords from Smith's Sound to Disco Bay, as here the sea is sufficiently deep to float them away, in spite of the enormous magnitude they frequently attain. As they drift along down Baffin's Bay and Davis's Strait, they not seldom run aground on some shallow shore, where, bidding defiance to the short summer, they frequently remain for many a year.