[This is the southwest corner of a folding map, 16 × 12 inches, entitled “The Platt of Sayling for the discoverye of a passage into the South Sea, 1631,1632,” which belongs to James’s _Strange and Dangerous Voyage_, London, 1633. Mr. Charles Deane has two copies, both with photographic fac-similes of the map made from the copy now in the Barlow Library, New York. The Harvard College copy is defective. The map has a portrait of James, “ætatis suæ, 40.” (Cf. Sabin’s _Dictionary_, ix. 35,711; _Carter-Brown Catalogue_, ii. no. 400. Quaritch priced it in 1872, £36.) The narrative was reprinted in 1740, and is in the Collections of Churchill and Harris.—ED.]] Both voyages were substantially failures, and their want of success nearly put an end to northwestern explorations. It was more than a hundred years before the matter was again taken up in any deliberate and efficient manner. But in the long list of Arctic navigators there are no greater names than those of Frobisher, Davis, Hudson, and Baffin. With means utterly disproportioned, as it now seems, to the task which they undertook, these men accomplished results which have called forth the admiration of more than one of their successors. They did not find the new and more direct way to Cathay which they sought for; but they dispelled many geographical illusions, and every fresh advance in our knowledge of the Arctic regions has only confirmed the accuracy of their statements. The story of these later explorations belongs to another part of this History; and we shall there see an energy and perseverance and an heroic endurance of hardship for the solution of great geographical problems not unworthy of the men whose voyages have been here narrated. CRITICAL ESSAY ON THE SOURCES OF INFORMATION. A COMPLETE bibliography of the northwest explorations is apart from our present purpose.[202] The principal works used in the preparation of the preceding narrative were almost all of them written by the men who were the chief actors in the scenes and incidents described, or are based on the original journals of those men. Their general accuracy and trustworthiness have never been challenged, and with some unimportant exceptions the statements of the early navigators have been confirmed by their successors. The men who first encountered the perils of those unknown seas were men of plain, straightforward character, who told in simple and unpretentious words what they saw and did. Some rectifications of their opinions and descriptions have, it is true, become necessary; in part through the imperfections of the early astronomical instruments, and in part through the difficulty, often very great, of deciding what was land and what water, even from the most careful observation. As a general rule, the early latitudes are given too high from the first of these causes; but the longitudes are substantially correct.