One after the other all said they were willing to abide by whatever the inventor did. Accordingly he made his preparations. Washington, with a hammer and chisel, was set to cutting a fair sized hole in the big rock, as far away from the ship as possible. He was two days at the job, and, during this time those on the stranded _Porpoise_ watched in vain for the sight of a vessel. "I am going to put the dynamite in," announced Mr. Henderson one morning. "We must all get into the small boat and row some distance away, as there is no telling what the result of the explosion may be." "Suppose the submarine is destroyed?" asked Mrs. Johnson. "Then we will have to sail for the nearest land in the small boat," replied the captain. "I will provision it and we will take all the precautions we can." It was with anxious hearts that the little party embarked in the little craft that was carried on the _Porpoise_. It was barely large enough to hold them. The professor was the last in, and he lighted a long fuse that led to the dynamite before taking his seat. Then with Tom and Bill at the oars the little craft moved away. "How long before the explosion will take place?" asked Jack. "I timed the fuse for ten minutes," answered Mr. Henderson. "That will enable us to get far enough away so we will not be swamped by a wave." Five minutes later Mark, who was intently watching the volcanic rock, gave a loud cry. "There she goes!" he shouted. They all looked to behold a wonderful thing. As easily as though it was some conjuring trick the rock began to settle down in the water. Lower and lower it went until only the tallest jagged points showed above the waves, whose crested tops the keel of the ship now almost touched. "That isn't the explosion!" exclaimed the professor. "The fuse has not had time to get to the powder yet." "But the rock is disappearing!" yelled Andy. As he spoke the big pile of volcanic stone vanished completely and the _Porpoise_ floated easily on the surface of the sea. "Hurrah!" cried Mark. "It am de most kloslostrous occurranceness dat eber transpositioned itself!" exploded Washington. "Let's row back to the ship now!" cried Mark. "Not yet!" said the professor quickly. "The dynamite has not gone off yet." "There it goes now," remarked Jack. At that instant a big column of water shot upward and a dull rumbling could be heard. A few seconds later the little boat rocked violently from the effects of the waves. Then the sea became calm, and the _Porpoise_ could be seen dancing up and down on the heaving billows. "Now we can go back in safety," spoke Mr. Henderson, and Tom and Bill bent to the oars. "What happened?" asked Mrs. Johnson. "The rock seemed to disappear before the explosion occurred."