"We must use dynamite," he declared. "If we stay here on this desolate rock we are bound to perish sooner or later, for our food cannot last many months, though we have a large supply. We are out of the path of steamers and only by chance would one pass here. With care we may be able to blast the rock so that the ship will not be permanently damaged. What do you all say? I would like your advice, for this concerns all of us."
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.