It is necessary here to interpolate a few remarks in explanation of the difficulties which beset the Baffin Bay route of Arctic exploration. Geographers assert, and the assertion seems confirmed by the experience of navigators, that a surface-current is constantly flowing down this bay, and carrying great fleets of icebergs and shoals of ice-floes into the Atlantic from its southern channels--Lancaster, Jones, and Smith Sounds. Hence, at the head of the bay there exists a considerable open and navigable expanse, which extends for some distance up Lancaster and Smith Sounds during the summer and early winter, and is known as the “North Water.” But between this open expanse and Davis Strait lies an immense mass of ice, averaging from one hundred and seventy to two hundred miles in width, and blocking up the centre of Baffin Bay, so as to interrupt the approach to the north-west end. This is known as the “middle pack,” and consists of some ancient floe-pieces of great thickness, which may have been brought down from a distant part of the Arctic seas; of a wide extent of ice accumulated during each winter, about six or eight feet in thickness; and of the grand and gigantic icebergs which are so characteristic a feature of the Melville Bay scenery. A very large quantity of this pack is destroyed in each succeeding summer by the thaws, or by the swell and warm temperature of the Atlantic as the ice drifts southward. It is remarked of the Baffin Bay ice, that it is much lighter than that found in the Spitzbergen seas. The latter often occurs in single sheets, solid, transparent, and from twenty to thirty, and even forty, feet in thickness. In Baffin Bay the average thickness of the floes does not exceed five or six feet, and eight or ten feet is of very rare occurrence. From Baffin’s voyage, in 1616, until 1817, no attempt was made to force this “middle pack” and enter the North Water; but now the voyage is made every year, and three routes have been opened up. The first is called the “North-about Passage,” and lies along the Greenland coast; the second, or “Middle Passage,” only possible late in the season, is by entering the drift-ice in the centre of the bay; and the third, or “Southern Passage,” also only possible late in the season, along the west side of Baffin Bay. Once in the North Water, whichever route be attempted, all obstacles to an exploration of the unknown region may be considered at an end. From Cape York to Smith Sound the sea is always navigable in the summer months. It will thus be seen that the great highways to the Pole were discovered by William Baffin.