s 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."

"That's exactly what it was," explained the inventor. "By some strange
freak of nature the volcanic mass dropped back into the ocean a little
before I was ready to blow it to pieces. In settling dow