“Go on. Do your worst,” urged Ned. “If I am to spend the rest of my natural life on this chunk of ice, I want to know it as soon as possible. Let’s get it over.” Tom would not do a thing in haste, however. Not until he had made sure that the mechanism would work perfectly did he signal Brannigan to start his motors. He stood at the controls until the motors were roaring well before he started the propellers. The huge boat began to move slowly. Almost at once she lifted under the pressure of the propellers. Her nose came up like the head of a spirited horse. Mr. Wakefield Damon gave voice to one of his excited explosions: “Bless all my kites and balloons, she’s going up!” “That’s what we want!” exclaimed Ned. “The higher, the better!” She was going up! Better than she had ever taken the air before. Everybody in the pilot room broke into a cheer, and Tom Swift was as proud as ever he had felt before in his life over anything he had built. Put to the severest sort of test, the _Winged Arrow_ was making good. How proud his father would be when he told him of this jump-off from the bottom of the cleft in the huge iceberg! And Mary! Aside from the exploration party finding and rescuing her father, Tom knew that Mary Nestor would comprehend the feelings of the inventor of the flying boat which had made this success possible. On a short slant skyward, the plane rose higher and higher. The long Arctic day was just ended, the sun had dropped below the horizon’s edge, and a number of pale stars were showing in the vault above. The flying boat scaled the heights of the ice cliffs and finally poised over the deep cleft in which they had spent so many uncertain hours. Tom believed that his task here was done. He meant to fly now to Iceland, as he had promised Captain Karofsen, and leave the schooner captain and his men at some handy port. The young inventor had no intention of being entangled in any plot engendered by the Russian Government or its agents. Let all that be explained from America. He was sure that Monsieur Polansky had never obtained his credentials from the Navy Department by fair means and that there would be no real trouble awaiting him when he got back to Shopton. He smiled upon Ned, who stood beside him, and began to wheel the flying boat till her nose pointed to the east. Somewhere in that direction—so far away that he could not see it—lay Iceland. “What is that?” demanded Mr. Wakefield Damon suddenly. “Look at that smoke. Why, you’d think that ice mountain was a crater of a volcano! Bless my smokepipes! it is the equal of old Mount Hekla.” The phenomenon to which Mr. Damon pointed startled them all. A spiral of smoke seemed to be rising, as he said, out of the higher pinnacle of ice. The _Winged Arrow_ was circling that peak. How was it possible for smoke to come out of a hole in the ice when, as far as they knew, there was no living human being on the berg they were leaving?