Almost the whole of the explorations which we have hitherto described or referred to had for their motive some practical purpose, whether to reach the Spice Islands or to hunt big game. Even the excursions of Davis, Frobisher, Hudson, and Baffin in pursuit of the north-west passage, and of Barentz and Chancellor in search of the north-east passage, were really in pursuit of mercantile ends. It is only with James Cook that the era of purely scientific exploration begins, though it is fair to qualify this statement by observing that the Russian expedition under Behring, already referred to, was ordered by Peter the Great to determine a strictly geographical problem, though doubtless it had its bearings on Russian ambitions. Behring and Cook between them, as we have seen, settled the problem of the relations existing between the ends of the two continents Asia and America, but what remained still to the north of _terra firma_ within the Arctic Circle? That was the problem which the nineteenth century set itself to solve, and has very nearly succeeded in the solution. For the Arctic Circle we now possess maps that only show blanks over a few thousand square miles. This knowledge has been gained by slow degrees, and by the exercise of the most heroic courage and endurance. It is a heroic tate, in which love of adventure and zeal for science have combated with and conquered the horrors of an Arctic winter, the six months' darkness in silence and desolation, the excessive cold, and the dangers of starvation. It is impossible here to go into any of the details which rendered the tale of Arctic voyages one of the most stirring in human history. All we are concerned with here is the amount of new knowledge brought back by successive expeditions within the Arctic Circle. This region of the earth's surface is distinguished by a number of large islands in the eastern hemisphere, most of which were discovered at an early date. We have seen how the Norsemen landed and settled upon Greenland as early as the tenth century. Burrough sighted Nova Zembla in 1556; in one of the voyages in search of the north-east passage, though the very name (Russian for Newfoundland) implies that it had previously been sighted and named by Russian seamen. Barentz is credited with having sighted Spitzbergen. The numerous islands to the north of Siberia became known through the Russian investigations of Discheneff, Behring, and their followers; while the intricate network of islands to the north of the continent of North America had been slowly worked out during the search for the north-west passage. It was indeed in pursuit of this will-of-the-wisp that most of the discoveries in the Arctic Circle were made, and a general impetus given to Arctic exploration.