If the reader would further pursue the inquiry, let him place one leg of a pair of dividers on the map near the North Pole (say in latitude 86°, longitude 160° W.), and inscribe a circle two thousand miles in diameter, and he will have touched the margin of the land and the mean line of the ice-belt throughout its wide circuit, and have covered an area of more than three millions of square miles. Although this ice-belt has not been broken through, it has been penetrated in many places, and its southern margin has been followed, partly along the waters formed near the land by the discharging rivers of the Arctic water-sheds of Asia and America, and partly by working through the ice which is always more or less loosened by the summer. It was in this manner that various navigators have attempted the northwest passage; and it was after following the coast line from Behring Strait to Banks Land, and then pushing through the broken ice that Sir Robert McClure finally succeeded in effecting this long-sought-for passage--not, however, by carrying his ship completely through, but by traveling over the winter ice three hundred miles to Wellington Channel, whence he returned home through Baffin Bay in a ship that had come from the eastward. And it was in this same manner that Captain Collinson, passing from west to east, reached almost to the spot where perished Franklin, who had entered the ice from the opposite direction. And it is thus, also, that the Russians have explored the coasts of Siberia, meeting but two insurmountable obstacles to the navigation from the Atlantic to the Pacific side, namely, Cape Jakan, against which the ice is always jammed, and which Behring tried in vain to pass, and Cape Ceverro Vostochnoi, which the gallant young Lieutenant Prondtschikoff made such heroic efforts to surmount. And it was by the same method of navigation that the Amsterdam pilot, earnest old William Barentz, strove, in 1598, to find by the northeast a passage to Cathay. [Sidenote: ICE NAVIGATION.]