That actually was the main thing to worry about. And even when the party had reached the brink of the gorge and fortunately found a traversable path to the bottom of it and came in sight of the flying boat, the question as to whether or no they could get the _Winged Arrow_ into the air again was the all-important subject of their thoughts. CHAPTER XXIII STILL CRIPPLED Brannigan and his associates had become extremely anxious because of the absence of the captain of the flying boat and his friends. And when they reappeared at the bottom of the gorge with five of the lost men of whom they had been in search, the mechanicians were inclined to think it almost a miraculous happening. It was, however, rather a serious occasion. The fact that two of the castaways, as well as thirty thousand dollars in treasure, were utterly lost cast a cloud over all their minds. Besides, although the mechanicians had repaired the airtight pontoon and rigged it to the end of the seaplane wing again, there was a question in all their minds as to whether the big flying boat could be raised from the bottom of the ice gorge without bringing her into collision again with the walls. The five new passengers crowded the carrying quarters of the seaplane, too. She had not been built with the idea of carrying more than twelve people, and now there were sixteen. Tom believed that under a fair test the _Winged Arrow_ would sail with several tons more weight than she had ever yet carried. But this jump-off was going to be no fair test. “We’ve got to take a chance,” said the young inventor. “If only we are successful!” murmured Ned. When they were all inside and the doors were closed, the young inventor went over the machinery with great care, personally trying out each part. He dared not empty the compressed air tanks, although he would have liked to do that until the plane had risen above the walls of the gorge. The air was needed for balance, however; he was confident of that. There was not room to turn the plane around as she rested on her wheels and tail, the ice cliffs were too near together; while ahead of her was a very short straight run for her to gain the speed to fly. It was a ticklish undertaking. If, under the thrust of her powerful motors, she went head on into one wall or the other of the cañon, Tom was pretty sure that the _Winged Arrow_ would never get out of the heart of this giant iceberg. “If we leave both the plane and Mr. Damon’s treasure here in the ice, we shall certainly have to mark this venture down as a total loss,” murmured Tom, to his chum. “Huh! we won’t mark anything down,” replied Ned. “We will have a hot time ever getting to land. Don’t forget that.” “I am not likely to overlook it,” confessed the young inventor. “I never had one of my inventions put to so severe a test before. And our lives, you must remember, depend upon the thing working right.”