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. [Illustration: 20. THE SEA-EAGLE.] 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. [Illustration: 21. ARCTIC NAVIGATION.] CHAPTER III. THE ARCTIC SEAS. 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?