The ascent of the nearest iceberg was not such a difficult piece of work as it would have been in the days when Sammy Block and Captain Hubbell were boys. The climbers wore ice-shoes with leather suckers on the soles, such as the feet of flies are furnished with, so that it was almost impossible for them to slip; and when they came to a sloping surface, where it was too steep for them to climb, they made use of a motor sledge furnished with a wheel different from the others. Instead of points, this wheel had on its outer rim a series of suckers, similar to those upon the soles of the shoes of the party. As the wheel, which was of extraordinary strength, revolved, it held its rim tightly to whatever surface it was pressed against, without reference to the angle of said surface. In 1941, with such a sledge, Martin Gallinet, a Swiss guide, ascended seventy-five feet of a perpendicular rock face on Monte Rosa. The sledge, slowly propelled by its wheel, went up the face of the rock as if it had been a fly climbing up a pane of glass, and Gallinet, suspended below this sledge by a strap under his arms, was hauled to the top of the precipice. It was not necessary to climb any such precipices in ascending an iceberg, but there were some steep slopes, and up these the party were safely carried, one by one, by what they called their Fly-foot Sledge. After an hour or two of climbing, our party safely reached the topmost point of the iceberg, and began to gaze about them. They soon found that beyond them there were other peaks and pinnacles, and that it would have been difficult to make a circuit which would enable them to continue Mr. Marcy's plan of a canal along the level ice. Far beyond them, to the south, ice hills and ice mountains were scattered here and there. Suddenly Mr. Gibbs gave a shout of surprise. “I have been here before,” said he. “Of course you have,” replied Mr. Marcy. “This is Lake Shiver. Don't you see, away over there on the other side of the open water below us, that little dark spot in the icy wall? That is the frozen polar bear. Take your glass and see if it isn't.” CHAPTER XIX. THE ICY GATEWAY When Mr. Gibbs and his party returned to the Dipsey, after descending the iceberg, their report created a lively sensation. “Why, it's like goin' home,” said Mrs. Block. “Perhaps I may find my shoes.” It was not a very strange thing that they should have again met with this little ice-locked lake, for they had endeavored to return by a route as directly south as the other had been directly north. But no one had expected to see the lake again, and they were not only surprised, but pleased and encouraged. Here was a spot where they knew the water was deep enough for perfectly safe submarine navigation, and if they could start here under the ice they would feel quite sure that they would meet with no obstacles on the rest of their voyage.