But Jack Darrow noticed a certain fact. That was that the debris from the spouter was not shot so high as at first. Therefore, it was not being spread abroad so far. Only small stones, now, were dropping around the tool shed. And the rear wall of the shanty was made of the most flimsy material. Suddenly he slipped down to one side and got upon the level of the valley. Nobody but Mark noticed his movements for a minute, and to him Jack had given a warning glance. The boy had crossed to the back of the tool-shed before the men of the party noticed his absence from the knoll. "Look at that reckless fellow!" ejaculated the professor. "Come back here, Jack!" But Master Jack was already at the shed. He tore away a part of the rear wall in a moment. The mud rained down upon him, but fortunately no rock came his way. There was light enough yet for him to see inside the hut. Andy Sudds had already started after Jack, and when the latter dragged the small forge out of the shelter, the old hunter picked it up, flung it upon his shoulder, and trotted back to the highland. "Come away! Come away, Jack!" cried the professor again. But the youth stopped long enough to obtain a sledge hammer and other tools that he knew they should need. As he ran from the hut two stones shot out by the geyser crashed through the roof; but he escaped all injury. He was plastered with mud from head to foot, however, when he regained the high land. "It was worth it," Jack declared, laughing, when he was safe. "I want to get away from this neighborhood just as quick as we can. And if we can fix the _Snowbird_ let us do it this very night and take our flight for other climes. We don't know when another earthquake or volcanic eruption will occur." "Very true, my boy," admitted the professor, with a sigh. "At least, we will endeavor to repair the damage done to your flying machine at once. But there is much going on here that interests me." Andy and Jack set up the forge and in a few minutes they had a glowing fire in it. Then the boys set to work welding the broken rods and straightening those that had become bent. Meanwhile Mr. Roebach hauled out his sled and whipped the dogs into line so that he could gear them up. The canines acted badly because they were more used to their Indian masters. When the boys had done their work, however, the oil man was ready to transport them all up the mountainside to the plateau where the _Snowbird_ lay. His cabin was by this time riddled by the flying stones and everything in and about it was plastered with mud. It would have been foolhardy indeed to attempt to get at the provisions. "You see," Mark said, "we are forced to get away in the _Snowbird_ at once, or to escape to some town where we can get food. There isn't much left of our stores on the flying machine." "And what will Mr. Roebach do about his dogs? They must be fed," said Jack. "He'll have to abandon them if he goes with us on the _Snowbird_," returned his chum.