Except for one most alarming experience, when in a terrific gale the ice made a stupendous attempt against the invading ship, the winter was spent rather with anxiety about the future than with worry about the present. No wonder that Peary speculated over what awaited him when he started upon his great march. After leaving Cape Columbia, over 400 miles separated him from his goal, and these miles had to be travelled over the ice of the Polar sea. "There is no land," he writes, "_between Cape Columbia and the North Pole, and no smooth and very little level ice._" But even ice through which the traveller must sometimes pick-axe his way is not the most serious impediment to those who would reach the Pole. The great obstacles--the ever-present source of anxiety--are the "leads" which constantly appear. These "leads" are really patches of open water, varying in extent, which the winds and tides cause in the ice's movement. For no reason that is apparent, these dangerous obstacles suddenly block the explorer's advance, and little can be done save to wait for them to remove themselves. These "leads" were to be Peary's greatest impediment in his march, and were destined to be fatal to one valued member of his party. The final attack on the Pole began on 15th February, 1909, when Bartlett, with a pioneer party, left the Roosevelt, and a week later Peary started on his way. At this time 7 members of the expedition, 19 Eskimos, 140 dogs, and 28 sledges, divided into various parties, were engaged in the great effort to reach the Pole. It was arranged that all of these parties should meet Peary at Cape Columbia on the last day of February; and on that day Bartlett and Borop started from the cape with advance parties. The duties of these advance parties were as onerous as they were important. For it was to Bartlett that Peary looked for a trail by which the main party could travel. On the second day's march, after Peary had left Cape Columbia and the land behind him, he met with his first open "lead," and a slight delay occurred. But on the following day this "lead" was covered with young ice, and Peary determined to cross it. "If the reader," he wrote, "will imagine crossing a river on a succession of gigantic shingles, one, two, or three deep, and all afloat and moving, he will perhaps form an idea of the uncertain surface over which we crossed this 'lead.' Such a passage is distinctly trying, as any moment may lose a sledge and its team, or plunge a member of the party into the icy water." And later on, when Borop was crossing an open crack, his dogs fell into the water, and the loss both of the dogs and the sledge with its invaluable load of provisions was only prevented by Borop's exceptional quickness and strength.