dras; but the Arctic fox (Canis lagopus) almost exclusively inhabits the treeless wastes that fringe the Polar Ocean, and is found on almost all the islands that lie buried in its bosom. This pretty little creature, which in winter grows perfectly white, knows how to protect itself against the most intense cold, either by seeking a refuge in the clefts of rocks, or by burrowing to a considerable depth in a sandy soil. It principally preys upon lemmings, stoats, polar hares, as well as upon all kinds of water-fowl and their eggs; but when pinched by hunger, it does not disdain the carcasses of fish, or the molluscs and crustaceans it may chance to pick up on the shore. Its enemies are the glutton, the snowy owl, and man, who, from the Equator to the poles, leaves no creature unmolested that can in any way satisfy his wants.

The lemmings, of which there are many species, are small rodents, peculiar to the Arctic regions, both in the New and in the Old World, where they are found as far to the north as vegetation extends. They live on grass, roots, the shoots of the willow, and the dwarf birch, but chiefly on lichens. They do not gather hoards of provisions for the winter, but live upon what they find beneath the snow. They seldom prove injurious to man, as the regions they inhabit are generally situated beyond the limits of agriculture. From the voles, to whom they are closely allied, they are distinguished by having the foot-sole covered with stiff hairs, and by the strong crooked claws with which their fore feet are armed. The best known species is the Norwegian lemming (Lemmus norwegicus), which is found on the high mountains of the Dovrefjeld, and farther to the north on the dry parts of the tundra, where it inhabits small burrows under stones or in the moss. Its long and thick hair is of a tawny color, and prettily marked with black spots. The migrations of the lemming have been grossly exaggerated by Olaus Magnus and Pontoppidan, to whom the natural history of the North owes so many fables. As they breed several times in the year, producing five or six at a birth, they of course multiply very fast under favorable circumstances, and are then forced to leave the district which is no longer able to afford them food. But this takes place very seldom, for when Mr. Brehm visited Scandinavia, the people on the Dovrefjeld knew nothing about the migrations of the lemming, and his inquiries on the subject proved equally fruitless in Lapland and in Finland. At all events, it is a fortunate circumstance that the lemmings have so many enemies, as their rapid multiplication might else endanger the balance of existence in the northern regions. The inclemencies of the climate are a chief means for keeping them in check. A wet summer, an early cold and snowless autumn destroy them by millions, and then of course years are necessary to recruit their numbers. With the exception of the bear and the hedgehog, they are pursued by all the northern carnivora. The wolf, the fox, the glutton, the marten, the ermine devour them with avidity, and a good lemming season is a time of unusual plenty for the hungry Laplander's dog. The snowy owl, whose dense plumage enables it to be a constant resident on the tundra, almost exclusively frequents those places where lemmings, its favorite food, are to be found; the buzzards are constantly active in their destruction; the crow feeds its young with lemmings; and even the poor Lap, when pressed by hunger, seizes a stick, and,

for want of better game, goes out lemming-hunting, and rejoices when he can kill a sufficient number for his dinner.

Several birds, such as the snowy owl and the ptarmigan (Lagopus albus), which can easily procure its food under the snow, winter in the highest latitudes; but by far the greater number are merely summer visitants of the Arctic regions. After the little bunting, the first arrivals in spring are the snowgeese, who likewise are the first to leave the dreary regions of the north on their southerly migration. The common and king eider-duck, the Brent geese,

the great northern black and red throated divers, are the next to make their appearance, followed by the pintail and longtail ducks (Anas caudacuta and 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 snow-bunting (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 ccld 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.

BERNIDE GOOSE.

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 ease upon the snow.

Among the raptorial birds of the Arctic regions, the sea-eagle (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 sea-birds 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 re-appearance 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 Kamschatka 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.

J.W.ORF.X.Y.

Dangers peculiar to the Arctic Sea.-Ice-fields.-Hummocks.-Collision of Ice-fields.-Icebergs.-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 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 icebergs 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 con

fusion 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.