Hardly had it been learned that Columbus was mistaken in his belief, and that the shores he had discovered were not those of India and Cathay, when vigorous efforts began to find some easy route to the rich lands of the Orient. Balboa, in 1513, crossed the continent at its narrow neck, and gazed, with astounded eyes, upon the mighty ocean that lay beyond,--the world's greatest sea. Magellan, in 1520, sailed round the continent at its southern extremity, and turned his daring prows into that world of waters of seemingly illimitable width. But the route thus laid out was far too long for the feeble commerce of that early day, and various efforts were made to pass the line of the continent at some northern point. The great rivers of North America, the James, the Hudson, and others, were explored in the eager hope that they might prove to be liquid canals between the two great seas. But a more promising hope was that which hinted that America might be circumnavigated at the north as well as at the south, and the Pacific be reached by way of the icy channel of the northern seas. This hope, born so long ago, has but died out in our own days. Much of the most thrilling literature of adventure of the nineteenth century comes from the persistent efforts to traverse these perilous Arctic ocean wastes. Let us go back to the oldest of the daring navigators of this frozen sea, the worthy knight Sir Martin Frobisher, and tell the story of his notable efforts to discover a Northwest Passage, "the only thing left undone," as he quaintly says, "whereby a notable mind might become famous and fortunate." As an interesting preface to our story we may quote from that curious old tome, "Purchas his Pilgrimage," the following quaintly imaginative passage,--