THE fresh spirit of maritime adventure which marked the last decade of the fifteenth century and the first quarter of the sixteenth century, owed its origin to mistaken theories as to the distance between the west of Europe and the east of Asia. Columbus believed that the land which he first discovered was an island on the coast of Japan; and he seems never to have relinquished this idea. The contemporary geographers all cherished the same mistake; and the early maps give a much better representation of the coast-line of Asia than they do of the shores of North America.[185] It is a curious fact that the true position and form of South America were familiar to cartographers long before there was any exact knowledge of the northern half of the continent. North America was regarded as an island or a collection of islands, through which it would not be difficult to find a short passage to Zipangu and Cathay,—the modern Japan and China.[186] Gradually these mistakes yielded to more correct views; but it was still believed that a feasible passage existed around the northern shore of the new continent. This belief was the inspiring motive of all the early northwestern explorations, and it lingered almost to our own time, long after every one knew that such a passage would be of no practical use. At length the problem has been solved; but the introduction of new methods of ocean and land trade and travel has deprived it of all but a purely scientific and geographical interest. Meanwhile the search for a northwest passage has developed an heroic endurance and a perseverance in surmounting obstacles scarcely paralleled anywhere else, and has added largely to the stores of human knowledge. At the head of the long list of explorers for a northwest passage stand the names of the Cabots; but the intricate questions as to the measure of just fame to be assigned to father and son have been fully treated in another chapter of this work,[187] and neither John nor Sebastian penetrated the more northern waters with which our inquiry is mainly concerned. It is enough now to recall their names as the leaders in an enterprise in which for nearly three centuries England took a foremost part, and that so early as 1497 John Cabot set sail in the hope of this great discovery. Within the next half century he was followed by his son Sebastian, the Cortereals, Cartier, and Hore, not one of whom sought to reach a high northern latitude. It was not until Frobisher sailed on his first voyage that the real northwest explorations can be said fairly to have begun. Since that time more than one hundred voyages and land journeys have been undertaken in this vain quest.